xref: /freebsd/contrib/sqlite3/sqlite3.h (revision 744bfb213144c63cbaf38d91a1c4f7aebb9b9fbc)
1 /*
2 ** 2001-09-15
3 **
4 ** The author disclaims copyright to this source code.  In place of
5 ** a legal notice, here is a blessing:
6 **
7 **    May you do good and not evil.
8 **    May you find forgiveness for yourself and forgive others.
9 **    May you share freely, never taking more than you give.
10 **
11 *************************************************************************
12 ** This header file defines the interface that the SQLite library
13 ** presents to client programs.  If a C-function, structure, datatype,
14 ** or constant definition does not appear in this file, then it is
15 ** not a published API of SQLite, is subject to change without
16 ** notice, and should not be referenced by programs that use SQLite.
17 **
18 ** Some of the definitions that are in this file are marked as
19 ** "experimental".  Experimental interfaces are normally new
20 ** features recently added to SQLite.  We do not anticipate changes
21 ** to experimental interfaces but reserve the right to make minor changes
22 ** if experience from use "in the wild" suggest such changes are prudent.
23 **
24 ** The official C-language API documentation for SQLite is derived
25 ** from comments in this file.  This file is the authoritative source
26 ** on how SQLite interfaces are supposed to operate.
27 **
28 ** The name of this file under configuration management is "sqlite.h.in".
29 ** The makefile makes some minor changes to this file (such as inserting
30 ** the version number) and changes its name to "sqlite3.h" as
31 ** part of the build process.
32 */
33 #ifndef SQLITE3_H
34 #define SQLITE3_H
35 #include <stdarg.h>     /* Needed for the definition of va_list */
36 
37 /*
38 ** Make sure we can call this stuff from C++.
39 */
40 #ifdef __cplusplus
41 extern "C" {
42 #endif
43 
44 
45 /*
46 ** Facilitate override of interface linkage and calling conventions.
47 ** Be aware that these macros may not be used within this particular
48 ** translation of the amalgamation and its associated header file.
49 **
50 ** The SQLITE_EXTERN and SQLITE_API macros are used to instruct the
51 ** compiler that the target identifier should have external linkage.
52 **
53 ** The SQLITE_CDECL macro is used to set the calling convention for
54 ** public functions that accept a variable number of arguments.
55 **
56 ** The SQLITE_APICALL macro is used to set the calling convention for
57 ** public functions that accept a fixed number of arguments.
58 **
59 ** The SQLITE_STDCALL macro is no longer used and is now deprecated.
60 **
61 ** The SQLITE_CALLBACK macro is used to set the calling convention for
62 ** function pointers.
63 **
64 ** The SQLITE_SYSAPI macro is used to set the calling convention for
65 ** functions provided by the operating system.
66 **
67 ** Currently, the SQLITE_CDECL, SQLITE_APICALL, SQLITE_CALLBACK, and
68 ** SQLITE_SYSAPI macros are used only when building for environments
69 ** that require non-default calling conventions.
70 */
71 #ifndef SQLITE_EXTERN
72 # define SQLITE_EXTERN extern
73 #endif
74 #ifndef SQLITE_API
75 # define SQLITE_API
76 #endif
77 #ifndef SQLITE_CDECL
78 # define SQLITE_CDECL
79 #endif
80 #ifndef SQLITE_APICALL
81 # define SQLITE_APICALL
82 #endif
83 #ifndef SQLITE_STDCALL
84 # define SQLITE_STDCALL SQLITE_APICALL
85 #endif
86 #ifndef SQLITE_CALLBACK
87 # define SQLITE_CALLBACK
88 #endif
89 #ifndef SQLITE_SYSAPI
90 # define SQLITE_SYSAPI
91 #endif
92 
93 /*
94 ** These no-op macros are used in front of interfaces to mark those
95 ** interfaces as either deprecated or experimental.  New applications
96 ** should not use deprecated interfaces - they are supported for backwards
97 ** compatibility only.  Application writers should be aware that
98 ** experimental interfaces are subject to change in point releases.
99 **
100 ** These macros used to resolve to various kinds of compiler magic that
101 ** would generate warning messages when they were used.  But that
102 ** compiler magic ended up generating such a flurry of bug reports
103 ** that we have taken it all out and gone back to using simple
104 ** noop macros.
105 */
106 #define SQLITE_DEPRECATED
107 #define SQLITE_EXPERIMENTAL
108 
109 /*
110 ** Ensure these symbols were not defined by some previous header file.
111 */
112 #ifdef SQLITE_VERSION
113 # undef SQLITE_VERSION
114 #endif
115 #ifdef SQLITE_VERSION_NUMBER
116 # undef SQLITE_VERSION_NUMBER
117 #endif
118 
119 /*
120 ** CAPI3REF: Compile-Time Library Version Numbers
121 **
122 ** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header
123 ** evaluates to a string literal that is the SQLite version in the
124 ** format "X.Y.Z" where X is the major version number (always 3 for
125 ** SQLite3) and Y is the minor version number and Z is the release number.)^
126 ** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer
127 ** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same
128 ** numbers used in [SQLITE_VERSION].)^
129 ** The SQLITE_VERSION_NUMBER for any given release of SQLite will also
130 ** be larger than the release from which it is derived.  Either Y will
131 ** be held constant and Z will be incremented or else Y will be incremented
132 ** and Z will be reset to zero.
133 **
134 ** Since [version 3.6.18] ([dateof:3.6.18]),
135 ** SQLite source code has been stored in the
136 ** <a href="http://www.fossil-scm.org/">Fossil configuration management
137 ** system</a>.  ^The SQLITE_SOURCE_ID macro evaluates to
138 ** a string which identifies a particular check-in of SQLite
139 ** within its configuration management system.  ^The SQLITE_SOURCE_ID
140 ** string contains the date and time of the check-in (UTC) and a SHA1
141 ** or SHA3-256 hash of the entire source tree.  If the source code has
142 ** been edited in any way since it was last checked in, then the last
143 ** four hexadecimal digits of the hash may be modified.
144 **
145 ** See also: [sqlite3_libversion()],
146 ** [sqlite3_libversion_number()], [sqlite3_sourceid()],
147 ** [sqlite_version()] and [sqlite_source_id()].
148 */
149 #define SQLITE_VERSION        "3.39.3"
150 #define SQLITE_VERSION_NUMBER 3039003
151 #define SQLITE_SOURCE_ID      "2022-09-05 11:02:23 4635f4a69c8c2a8df242b384a992aea71224e39a2ccab42d8c0b0602f1e826e8"
152 
153 /*
154 ** CAPI3REF: Run-Time Library Version Numbers
155 ** KEYWORDS: sqlite3_version sqlite3_sourceid
156 **
157 ** These interfaces provide the same information as the [SQLITE_VERSION],
158 ** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros
159 ** but are associated with the library instead of the header file.  ^(Cautious
160 ** programmers might include assert() statements in their application to
161 ** verify that values returned by these interfaces match the macros in
162 ** the header, and thus ensure that the application is
163 ** compiled with matching library and header files.
164 **
165 ** <blockquote><pre>
166 ** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
167 ** assert( strncmp(sqlite3_sourceid(),SQLITE_SOURCE_ID,80)==0 );
168 ** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
169 ** </pre></blockquote>)^
170 **
171 ** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION]
172 ** macro.  ^The sqlite3_libversion() function returns a pointer to the
173 ** to the sqlite3_version[] string constant.  The sqlite3_libversion()
174 ** function is provided for use in DLLs since DLL users usually do not have
175 ** direct access to string constants within the DLL.  ^The
176 ** sqlite3_libversion_number() function returns an integer equal to
177 ** [SQLITE_VERSION_NUMBER].  ^(The sqlite3_sourceid() function returns
178 ** a pointer to a string constant whose value is the same as the
179 ** [SQLITE_SOURCE_ID] C preprocessor macro.  Except if SQLite is built
180 ** using an edited copy of [the amalgamation], then the last four characters
181 ** of the hash might be different from [SQLITE_SOURCE_ID].)^
182 **
183 ** See also: [sqlite_version()] and [sqlite_source_id()].
184 */
185 SQLITE_API SQLITE_EXTERN const char sqlite3_version[];
186 SQLITE_API const char *sqlite3_libversion(void);
187 SQLITE_API const char *sqlite3_sourceid(void);
188 SQLITE_API int sqlite3_libversion_number(void);
189 
190 /*
191 ** CAPI3REF: Run-Time Library Compilation Options Diagnostics
192 **
193 ** ^The sqlite3_compileoption_used() function returns 0 or 1
194 ** indicating whether the specified option was defined at
195 ** compile time.  ^The SQLITE_ prefix may be omitted from the
196 ** option name passed to sqlite3_compileoption_used().
197 **
198 ** ^The sqlite3_compileoption_get() function allows iterating
199 ** over the list of options that were defined at compile time by
200 ** returning the N-th compile time option string.  ^If N is out of range,
201 ** sqlite3_compileoption_get() returns a NULL pointer.  ^The SQLITE_
202 ** prefix is omitted from any strings returned by
203 ** sqlite3_compileoption_get().
204 **
205 ** ^Support for the diagnostic functions sqlite3_compileoption_used()
206 ** and sqlite3_compileoption_get() may be omitted by specifying the
207 ** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time.
208 **
209 ** See also: SQL functions [sqlite_compileoption_used()] and
210 ** [sqlite_compileoption_get()] and the [compile_options pragma].
211 */
212 #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
213 SQLITE_API int sqlite3_compileoption_used(const char *zOptName);
214 SQLITE_API const char *sqlite3_compileoption_get(int N);
215 #else
216 # define sqlite3_compileoption_used(X) 0
217 # define sqlite3_compileoption_get(X)  ((void*)0)
218 #endif
219 
220 /*
221 ** CAPI3REF: Test To See If The Library Is Threadsafe
222 **
223 ** ^The sqlite3_threadsafe() function returns zero if and only if
224 ** SQLite was compiled with mutexing code omitted due to the
225 ** [SQLITE_THREADSAFE] compile-time option being set to 0.
226 **
227 ** SQLite can be compiled with or without mutexes.  When
228 ** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
229 ** are enabled and SQLite is threadsafe.  When the
230 ** [SQLITE_THREADSAFE] macro is 0,
231 ** the mutexes are omitted.  Without the mutexes, it is not safe
232 ** to use SQLite concurrently from more than one thread.
233 **
234 ** Enabling mutexes incurs a measurable performance penalty.
235 ** So if speed is of utmost importance, it makes sense to disable
236 ** the mutexes.  But for maximum safety, mutexes should be enabled.
237 ** ^The default behavior is for mutexes to be enabled.
238 **
239 ** This interface can be used by an application to make sure that the
240 ** version of SQLite that it is linking against was compiled with
241 ** the desired setting of the [SQLITE_THREADSAFE] macro.
242 **
243 ** This interface only reports on the compile-time mutex setting
244 ** of the [SQLITE_THREADSAFE] flag.  If SQLite is compiled with
245 ** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
246 ** can be fully or partially disabled using a call to [sqlite3_config()]
247 ** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD],
248 ** or [SQLITE_CONFIG_SERIALIZED].  ^(The return value of the
249 ** sqlite3_threadsafe() function shows only the compile-time setting of
250 ** thread safety, not any run-time changes to that setting made by
251 ** sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
252 ** is unchanged by calls to sqlite3_config().)^
253 **
254 ** See the [threading mode] documentation for additional information.
255 */
256 SQLITE_API int sqlite3_threadsafe(void);
257 
258 /*
259 ** CAPI3REF: Database Connection Handle
260 ** KEYWORDS: {database connection} {database connections}
261 **
262 ** Each open SQLite database is represented by a pointer to an instance of
263 ** the opaque structure named "sqlite3".  It is useful to think of an sqlite3
264 ** pointer as an object.  The [sqlite3_open()], [sqlite3_open16()], and
265 ** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
266 ** and [sqlite3_close_v2()] are its destructors.  There are many other
267 ** interfaces (such as
268 ** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
269 ** [sqlite3_busy_timeout()] to name but three) that are methods on an
270 ** sqlite3 object.
271 */
272 typedef struct sqlite3 sqlite3;
273 
274 /*
275 ** CAPI3REF: 64-Bit Integer Types
276 ** KEYWORDS: sqlite_int64 sqlite_uint64
277 **
278 ** Because there is no cross-platform way to specify 64-bit integer types
279 ** SQLite includes typedefs for 64-bit signed and unsigned integers.
280 **
281 ** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
282 ** The sqlite_int64 and sqlite_uint64 types are supported for backwards
283 ** compatibility only.
284 **
285 ** ^The sqlite3_int64 and sqlite_int64 types can store integer values
286 ** between -9223372036854775808 and +9223372036854775807 inclusive.  ^The
287 ** sqlite3_uint64 and sqlite_uint64 types can store integer values
288 ** between 0 and +18446744073709551615 inclusive.
289 */
290 #ifdef SQLITE_INT64_TYPE
291   typedef SQLITE_INT64_TYPE sqlite_int64;
292 # ifdef SQLITE_UINT64_TYPE
293     typedef SQLITE_UINT64_TYPE sqlite_uint64;
294 # else
295     typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
296 # endif
297 #elif defined(_MSC_VER) || defined(__BORLANDC__)
298   typedef __int64 sqlite_int64;
299   typedef unsigned __int64 sqlite_uint64;
300 #else
301   typedef long long int sqlite_int64;
302   typedef unsigned long long int sqlite_uint64;
303 #endif
304 typedef sqlite_int64 sqlite3_int64;
305 typedef sqlite_uint64 sqlite3_uint64;
306 
307 /*
308 ** If compiling for a processor that lacks floating point support,
309 ** substitute integer for floating-point.
310 */
311 #ifdef SQLITE_OMIT_FLOATING_POINT
312 # define double sqlite3_int64
313 #endif
314 
315 /*
316 ** CAPI3REF: Closing A Database Connection
317 ** DESTRUCTOR: sqlite3
318 **
319 ** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors
320 ** for the [sqlite3] object.
321 ** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if
322 ** the [sqlite3] object is successfully destroyed and all associated
323 ** resources are deallocated.
324 **
325 ** Ideally, applications should [sqlite3_finalize | finalize] all
326 ** [prepared statements], [sqlite3_blob_close | close] all [BLOB handles], and
327 ** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated
328 ** with the [sqlite3] object prior to attempting to close the object.
329 ** ^If the database connection is associated with unfinalized prepared
330 ** statements, BLOB handlers, and/or unfinished sqlite3_backup objects then
331 ** sqlite3_close() will leave the database connection open and return
332 ** [SQLITE_BUSY]. ^If sqlite3_close_v2() is called with unfinalized prepared
333 ** statements, unclosed BLOB handlers, and/or unfinished sqlite3_backups,
334 ** it returns [SQLITE_OK] regardless, but instead of deallocating the database
335 ** connection immediately, it marks the database connection as an unusable
336 ** "zombie" and makes arrangements to automatically deallocate the database
337 ** connection after all prepared statements are finalized, all BLOB handles
338 ** are closed, and all backups have finished. The sqlite3_close_v2() interface
339 ** is intended for use with host languages that are garbage collected, and
340 ** where the order in which destructors are called is arbitrary.
341 **
342 ** ^If an [sqlite3] object is destroyed while a transaction is open,
343 ** the transaction is automatically rolled back.
344 **
345 ** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)]
346 ** must be either a NULL
347 ** pointer or an [sqlite3] object pointer obtained
348 ** from [sqlite3_open()], [sqlite3_open16()], or
349 ** [sqlite3_open_v2()], and not previously closed.
350 ** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer
351 ** argument is a harmless no-op.
352 */
353 SQLITE_API int sqlite3_close(sqlite3*);
354 SQLITE_API int sqlite3_close_v2(sqlite3*);
355 
356 /*
357 ** The type for a callback function.
358 ** This is legacy and deprecated.  It is included for historical
359 ** compatibility and is not documented.
360 */
361 typedef int (*sqlite3_callback)(void*,int,char**, char**);
362 
363 /*
364 ** CAPI3REF: One-Step Query Execution Interface
365 ** METHOD: sqlite3
366 **
367 ** The sqlite3_exec() interface is a convenience wrapper around
368 ** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
369 ** that allows an application to run multiple statements of SQL
370 ** without having to use a lot of C code.
371 **
372 ** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
373 ** semicolon-separate SQL statements passed into its 2nd argument,
374 ** in the context of the [database connection] passed in as its 1st
375 ** argument.  ^If the callback function of the 3rd argument to
376 ** sqlite3_exec() is not NULL, then it is invoked for each result row
377 ** coming out of the evaluated SQL statements.  ^The 4th argument to
378 ** sqlite3_exec() is relayed through to the 1st argument of each
379 ** callback invocation.  ^If the callback pointer to sqlite3_exec()
380 ** is NULL, then no callback is ever invoked and result rows are
381 ** ignored.
382 **
383 ** ^If an error occurs while evaluating the SQL statements passed into
384 ** sqlite3_exec(), then execution of the current statement stops and
385 ** subsequent statements are skipped.  ^If the 5th parameter to sqlite3_exec()
386 ** is not NULL then any error message is written into memory obtained
387 ** from [sqlite3_malloc()] and passed back through the 5th parameter.
388 ** To avoid memory leaks, the application should invoke [sqlite3_free()]
389 ** on error message strings returned through the 5th parameter of
390 ** sqlite3_exec() after the error message string is no longer needed.
391 ** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
392 ** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
393 ** NULL before returning.
394 **
395 ** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
396 ** routine returns SQLITE_ABORT without invoking the callback again and
397 ** without running any subsequent SQL statements.
398 **
399 ** ^The 2nd argument to the sqlite3_exec() callback function is the
400 ** number of columns in the result.  ^The 3rd argument to the sqlite3_exec()
401 ** callback is an array of pointers to strings obtained as if from
402 ** [sqlite3_column_text()], one for each column.  ^If an element of a
403 ** result row is NULL then the corresponding string pointer for the
404 ** sqlite3_exec() callback is a NULL pointer.  ^The 4th argument to the
405 ** sqlite3_exec() callback is an array of pointers to strings where each
406 ** entry represents the name of corresponding result column as obtained
407 ** from [sqlite3_column_name()].
408 **
409 ** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
410 ** to an empty string, or a pointer that contains only whitespace and/or
411 ** SQL comments, then no SQL statements are evaluated and the database
412 ** is not changed.
413 **
414 ** Restrictions:
415 **
416 ** <ul>
417 ** <li> The application must ensure that the 1st parameter to sqlite3_exec()
418 **      is a valid and open [database connection].
419 ** <li> The application must not close the [database connection] specified by
420 **      the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
421 ** <li> The application must not modify the SQL statement text passed into
422 **      the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
423 ** </ul>
424 */
425 SQLITE_API int sqlite3_exec(
426   sqlite3*,                                  /* An open database */
427   const char *sql,                           /* SQL to be evaluated */
428   int (*callback)(void*,int,char**,char**),  /* Callback function */
429   void *,                                    /* 1st argument to callback */
430   char **errmsg                              /* Error msg written here */
431 );
432 
433 /*
434 ** CAPI3REF: Result Codes
435 ** KEYWORDS: {result code definitions}
436 **
437 ** Many SQLite functions return an integer result code from the set shown
438 ** here in order to indicate success or failure.
439 **
440 ** New error codes may be added in future versions of SQLite.
441 **
442 ** See also: [extended result code definitions]
443 */
444 #define SQLITE_OK           0   /* Successful result */
445 /* beginning-of-error-codes */
446 #define SQLITE_ERROR        1   /* Generic error */
447 #define SQLITE_INTERNAL     2   /* Internal logic error in SQLite */
448 #define SQLITE_PERM         3   /* Access permission denied */
449 #define SQLITE_ABORT        4   /* Callback routine requested an abort */
450 #define SQLITE_BUSY         5   /* The database file is locked */
451 #define SQLITE_LOCKED       6   /* A table in the database is locked */
452 #define SQLITE_NOMEM        7   /* A malloc() failed */
453 #define SQLITE_READONLY     8   /* Attempt to write a readonly database */
454 #define SQLITE_INTERRUPT    9   /* Operation terminated by sqlite3_interrupt()*/
455 #define SQLITE_IOERR       10   /* Some kind of disk I/O error occurred */
456 #define SQLITE_CORRUPT     11   /* The database disk image is malformed */
457 #define SQLITE_NOTFOUND    12   /* Unknown opcode in sqlite3_file_control() */
458 #define SQLITE_FULL        13   /* Insertion failed because database is full */
459 #define SQLITE_CANTOPEN    14   /* Unable to open the database file */
460 #define SQLITE_PROTOCOL    15   /* Database lock protocol error */
461 #define SQLITE_EMPTY       16   /* Internal use only */
462 #define SQLITE_SCHEMA      17   /* The database schema changed */
463 #define SQLITE_TOOBIG      18   /* String or BLOB exceeds size limit */
464 #define SQLITE_CONSTRAINT  19   /* Abort due to constraint violation */
465 #define SQLITE_MISMATCH    20   /* Data type mismatch */
466 #define SQLITE_MISUSE      21   /* Library used incorrectly */
467 #define SQLITE_NOLFS       22   /* Uses OS features not supported on host */
468 #define SQLITE_AUTH        23   /* Authorization denied */
469 #define SQLITE_FORMAT      24   /* Not used */
470 #define SQLITE_RANGE       25   /* 2nd parameter to sqlite3_bind out of range */
471 #define SQLITE_NOTADB      26   /* File opened that is not a database file */
472 #define SQLITE_NOTICE      27   /* Notifications from sqlite3_log() */
473 #define SQLITE_WARNING     28   /* Warnings from sqlite3_log() */
474 #define SQLITE_ROW         100  /* sqlite3_step() has another row ready */
475 #define SQLITE_DONE        101  /* sqlite3_step() has finished executing */
476 /* end-of-error-codes */
477 
478 /*
479 ** CAPI3REF: Extended Result Codes
480 ** KEYWORDS: {extended result code definitions}
481 **
482 ** In its default configuration, SQLite API routines return one of 30 integer
483 ** [result codes].  However, experience has shown that many of
484 ** these result codes are too coarse-grained.  They do not provide as
485 ** much information about problems as programmers might like.  In an effort to
486 ** address this, newer versions of SQLite (version 3.3.8 [dateof:3.3.8]
487 ** and later) include
488 ** support for additional result codes that provide more detailed information
489 ** about errors. These [extended result codes] are enabled or disabled
490 ** on a per database connection basis using the
491 ** [sqlite3_extended_result_codes()] API.  Or, the extended code for
492 ** the most recent error can be obtained using
493 ** [sqlite3_extended_errcode()].
494 */
495 #define SQLITE_ERROR_MISSING_COLLSEQ   (SQLITE_ERROR | (1<<8))
496 #define SQLITE_ERROR_RETRY             (SQLITE_ERROR | (2<<8))
497 #define SQLITE_ERROR_SNAPSHOT          (SQLITE_ERROR | (3<<8))
498 #define SQLITE_IOERR_READ              (SQLITE_IOERR | (1<<8))
499 #define SQLITE_IOERR_SHORT_READ        (SQLITE_IOERR | (2<<8))
500 #define SQLITE_IOERR_WRITE             (SQLITE_IOERR | (3<<8))
501 #define SQLITE_IOERR_FSYNC             (SQLITE_IOERR | (4<<8))
502 #define SQLITE_IOERR_DIR_FSYNC         (SQLITE_IOERR | (5<<8))
503 #define SQLITE_IOERR_TRUNCATE          (SQLITE_IOERR | (6<<8))
504 #define SQLITE_IOERR_FSTAT             (SQLITE_IOERR | (7<<8))
505 #define SQLITE_IOERR_UNLOCK            (SQLITE_IOERR | (8<<8))
506 #define SQLITE_IOERR_RDLOCK            (SQLITE_IOERR | (9<<8))
507 #define SQLITE_IOERR_DELETE            (SQLITE_IOERR | (10<<8))
508 #define SQLITE_IOERR_BLOCKED           (SQLITE_IOERR | (11<<8))
509 #define SQLITE_IOERR_NOMEM             (SQLITE_IOERR | (12<<8))
510 #define SQLITE_IOERR_ACCESS            (SQLITE_IOERR | (13<<8))
511 #define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
512 #define SQLITE_IOERR_LOCK              (SQLITE_IOERR | (15<<8))
513 #define SQLITE_IOERR_CLOSE             (SQLITE_IOERR | (16<<8))
514 #define SQLITE_IOERR_DIR_CLOSE         (SQLITE_IOERR | (17<<8))
515 #define SQLITE_IOERR_SHMOPEN           (SQLITE_IOERR | (18<<8))
516 #define SQLITE_IOERR_SHMSIZE           (SQLITE_IOERR | (19<<8))
517 #define SQLITE_IOERR_SHMLOCK           (SQLITE_IOERR | (20<<8))
518 #define SQLITE_IOERR_SHMMAP            (SQLITE_IOERR | (21<<8))
519 #define SQLITE_IOERR_SEEK              (SQLITE_IOERR | (22<<8))
520 #define SQLITE_IOERR_DELETE_NOENT      (SQLITE_IOERR | (23<<8))
521 #define SQLITE_IOERR_MMAP              (SQLITE_IOERR | (24<<8))
522 #define SQLITE_IOERR_GETTEMPPATH       (SQLITE_IOERR | (25<<8))
523 #define SQLITE_IOERR_CONVPATH          (SQLITE_IOERR | (26<<8))
524 #define SQLITE_IOERR_VNODE             (SQLITE_IOERR | (27<<8))
525 #define SQLITE_IOERR_AUTH              (SQLITE_IOERR | (28<<8))
526 #define SQLITE_IOERR_BEGIN_ATOMIC      (SQLITE_IOERR | (29<<8))
527 #define SQLITE_IOERR_COMMIT_ATOMIC     (SQLITE_IOERR | (30<<8))
528 #define SQLITE_IOERR_ROLLBACK_ATOMIC   (SQLITE_IOERR | (31<<8))
529 #define SQLITE_IOERR_DATA              (SQLITE_IOERR | (32<<8))
530 #define SQLITE_IOERR_CORRUPTFS         (SQLITE_IOERR | (33<<8))
531 #define SQLITE_LOCKED_SHAREDCACHE      (SQLITE_LOCKED |  (1<<8))
532 #define SQLITE_LOCKED_VTAB             (SQLITE_LOCKED |  (2<<8))
533 #define SQLITE_BUSY_RECOVERY           (SQLITE_BUSY   |  (1<<8))
534 #define SQLITE_BUSY_SNAPSHOT           (SQLITE_BUSY   |  (2<<8))
535 #define SQLITE_BUSY_TIMEOUT            (SQLITE_BUSY   |  (3<<8))
536 #define SQLITE_CANTOPEN_NOTEMPDIR      (SQLITE_CANTOPEN | (1<<8))
537 #define SQLITE_CANTOPEN_ISDIR          (SQLITE_CANTOPEN | (2<<8))
538 #define SQLITE_CANTOPEN_FULLPATH       (SQLITE_CANTOPEN | (3<<8))
539 #define SQLITE_CANTOPEN_CONVPATH       (SQLITE_CANTOPEN | (4<<8))
540 #define SQLITE_CANTOPEN_DIRTYWAL       (SQLITE_CANTOPEN | (5<<8)) /* Not Used */
541 #define SQLITE_CANTOPEN_SYMLINK        (SQLITE_CANTOPEN | (6<<8))
542 #define SQLITE_CORRUPT_VTAB            (SQLITE_CORRUPT | (1<<8))
543 #define SQLITE_CORRUPT_SEQUENCE        (SQLITE_CORRUPT | (2<<8))
544 #define SQLITE_CORRUPT_INDEX           (SQLITE_CORRUPT | (3<<8))
545 #define SQLITE_READONLY_RECOVERY       (SQLITE_READONLY | (1<<8))
546 #define SQLITE_READONLY_CANTLOCK       (SQLITE_READONLY | (2<<8))
547 #define SQLITE_READONLY_ROLLBACK       (SQLITE_READONLY | (3<<8))
548 #define SQLITE_READONLY_DBMOVED        (SQLITE_READONLY | (4<<8))
549 #define SQLITE_READONLY_CANTINIT       (SQLITE_READONLY | (5<<8))
550 #define SQLITE_READONLY_DIRECTORY      (SQLITE_READONLY | (6<<8))
551 #define SQLITE_ABORT_ROLLBACK          (SQLITE_ABORT | (2<<8))
552 #define SQLITE_CONSTRAINT_CHECK        (SQLITE_CONSTRAINT | (1<<8))
553 #define SQLITE_CONSTRAINT_COMMITHOOK   (SQLITE_CONSTRAINT | (2<<8))
554 #define SQLITE_CONSTRAINT_FOREIGNKEY   (SQLITE_CONSTRAINT | (3<<8))
555 #define SQLITE_CONSTRAINT_FUNCTION     (SQLITE_CONSTRAINT | (4<<8))
556 #define SQLITE_CONSTRAINT_NOTNULL      (SQLITE_CONSTRAINT | (5<<8))
557 #define SQLITE_CONSTRAINT_PRIMARYKEY   (SQLITE_CONSTRAINT | (6<<8))
558 #define SQLITE_CONSTRAINT_TRIGGER      (SQLITE_CONSTRAINT | (7<<8))
559 #define SQLITE_CONSTRAINT_UNIQUE       (SQLITE_CONSTRAINT | (8<<8))
560 #define SQLITE_CONSTRAINT_VTAB         (SQLITE_CONSTRAINT | (9<<8))
561 #define SQLITE_CONSTRAINT_ROWID        (SQLITE_CONSTRAINT |(10<<8))
562 #define SQLITE_CONSTRAINT_PINNED       (SQLITE_CONSTRAINT |(11<<8))
563 #define SQLITE_CONSTRAINT_DATATYPE     (SQLITE_CONSTRAINT |(12<<8))
564 #define SQLITE_NOTICE_RECOVER_WAL      (SQLITE_NOTICE | (1<<8))
565 #define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8))
566 #define SQLITE_WARNING_AUTOINDEX       (SQLITE_WARNING | (1<<8))
567 #define SQLITE_AUTH_USER               (SQLITE_AUTH | (1<<8))
568 #define SQLITE_OK_LOAD_PERMANENTLY     (SQLITE_OK | (1<<8))
569 #define SQLITE_OK_SYMLINK              (SQLITE_OK | (2<<8)) /* internal use only */
570 
571 /*
572 ** CAPI3REF: Flags For File Open Operations
573 **
574 ** These bit values are intended for use in the
575 ** 3rd parameter to the [sqlite3_open_v2()] interface and
576 ** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
577 **
578 ** Only those flags marked as "Ok for sqlite3_open_v2()" may be
579 ** used as the third argument to the [sqlite3_open_v2()] interface.
580 ** The other flags have historically been ignored by sqlite3_open_v2(),
581 ** though future versions of SQLite might change so that an error is
582 ** raised if any of the disallowed bits are passed into sqlite3_open_v2().
583 ** Applications should not depend on the historical behavior.
584 **
585 ** Note in particular that passing the SQLITE_OPEN_EXCLUSIVE flag into
586 ** [sqlite3_open_v2()] does *not* cause the underlying database file
587 ** to be opened using O_EXCL.  Passing SQLITE_OPEN_EXCLUSIVE into
588 ** [sqlite3_open_v2()] has historically be a no-op and might become an
589 ** error in future versions of SQLite.
590 */
591 #define SQLITE_OPEN_READONLY         0x00000001  /* Ok for sqlite3_open_v2() */
592 #define SQLITE_OPEN_READWRITE        0x00000002  /* Ok for sqlite3_open_v2() */
593 #define SQLITE_OPEN_CREATE           0x00000004  /* Ok for sqlite3_open_v2() */
594 #define SQLITE_OPEN_DELETEONCLOSE    0x00000008  /* VFS only */
595 #define SQLITE_OPEN_EXCLUSIVE        0x00000010  /* VFS only */
596 #define SQLITE_OPEN_AUTOPROXY        0x00000020  /* VFS only */
597 #define SQLITE_OPEN_URI              0x00000040  /* Ok for sqlite3_open_v2() */
598 #define SQLITE_OPEN_MEMORY           0x00000080  /* Ok for sqlite3_open_v2() */
599 #define SQLITE_OPEN_MAIN_DB          0x00000100  /* VFS only */
600 #define SQLITE_OPEN_TEMP_DB          0x00000200  /* VFS only */
601 #define SQLITE_OPEN_TRANSIENT_DB     0x00000400  /* VFS only */
602 #define SQLITE_OPEN_MAIN_JOURNAL     0x00000800  /* VFS only */
603 #define SQLITE_OPEN_TEMP_JOURNAL     0x00001000  /* VFS only */
604 #define SQLITE_OPEN_SUBJOURNAL       0x00002000  /* VFS only */
605 #define SQLITE_OPEN_SUPER_JOURNAL    0x00004000  /* VFS only */
606 #define SQLITE_OPEN_NOMUTEX          0x00008000  /* Ok for sqlite3_open_v2() */
607 #define SQLITE_OPEN_FULLMUTEX        0x00010000  /* Ok for sqlite3_open_v2() */
608 #define SQLITE_OPEN_SHAREDCACHE      0x00020000  /* Ok for sqlite3_open_v2() */
609 #define SQLITE_OPEN_PRIVATECACHE     0x00040000  /* Ok for sqlite3_open_v2() */
610 #define SQLITE_OPEN_WAL              0x00080000  /* VFS only */
611 #define SQLITE_OPEN_NOFOLLOW         0x01000000  /* Ok for sqlite3_open_v2() */
612 #define SQLITE_OPEN_EXRESCODE        0x02000000  /* Extended result codes */
613 
614 /* Reserved:                         0x00F00000 */
615 /* Legacy compatibility: */
616 #define SQLITE_OPEN_MASTER_JOURNAL   0x00004000  /* VFS only */
617 
618 
619 /*
620 ** CAPI3REF: Device Characteristics
621 **
622 ** The xDeviceCharacteristics method of the [sqlite3_io_methods]
623 ** object returns an integer which is a vector of these
624 ** bit values expressing I/O characteristics of the mass storage
625 ** device that holds the file that the [sqlite3_io_methods]
626 ** refers to.
627 **
628 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
629 ** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
630 ** mean that writes of blocks that are nnn bytes in size and
631 ** are aligned to an address which is an integer multiple of
632 ** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
633 ** that when data is appended to a file, the data is appended
634 ** first then the size of the file is extended, never the other
635 ** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
636 ** information is written to disk in the same order as calls
637 ** to xWrite().  The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
638 ** after reboot following a crash or power loss, the only bytes in a
639 ** file that were written at the application level might have changed
640 ** and that adjacent bytes, even bytes within the same sector are
641 ** guaranteed to be unchanged.  The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN
642 ** flag indicates that a file cannot be deleted when open.  The
643 ** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on
644 ** read-only media and cannot be changed even by processes with
645 ** elevated privileges.
646 **
647 ** The SQLITE_IOCAP_BATCH_ATOMIC property means that the underlying
648 ** filesystem supports doing multiple write operations atomically when those
649 ** write operations are bracketed by [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] and
650 ** [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE].
651 */
652 #define SQLITE_IOCAP_ATOMIC                 0x00000001
653 #define SQLITE_IOCAP_ATOMIC512              0x00000002
654 #define SQLITE_IOCAP_ATOMIC1K               0x00000004
655 #define SQLITE_IOCAP_ATOMIC2K               0x00000008
656 #define SQLITE_IOCAP_ATOMIC4K               0x00000010
657 #define SQLITE_IOCAP_ATOMIC8K               0x00000020
658 #define SQLITE_IOCAP_ATOMIC16K              0x00000040
659 #define SQLITE_IOCAP_ATOMIC32K              0x00000080
660 #define SQLITE_IOCAP_ATOMIC64K              0x00000100
661 #define SQLITE_IOCAP_SAFE_APPEND            0x00000200
662 #define SQLITE_IOCAP_SEQUENTIAL             0x00000400
663 #define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN  0x00000800
664 #define SQLITE_IOCAP_POWERSAFE_OVERWRITE    0x00001000
665 #define SQLITE_IOCAP_IMMUTABLE              0x00002000
666 #define SQLITE_IOCAP_BATCH_ATOMIC           0x00004000
667 
668 /*
669 ** CAPI3REF: File Locking Levels
670 **
671 ** SQLite uses one of these integer values as the second
672 ** argument to calls it makes to the xLock() and xUnlock() methods
673 ** of an [sqlite3_io_methods] object.
674 */
675 #define SQLITE_LOCK_NONE          0
676 #define SQLITE_LOCK_SHARED        1
677 #define SQLITE_LOCK_RESERVED      2
678 #define SQLITE_LOCK_PENDING       3
679 #define SQLITE_LOCK_EXCLUSIVE     4
680 
681 /*
682 ** CAPI3REF: Synchronization Type Flags
683 **
684 ** When SQLite invokes the xSync() method of an
685 ** [sqlite3_io_methods] object it uses a combination of
686 ** these integer values as the second argument.
687 **
688 ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
689 ** sync operation only needs to flush data to mass storage.  Inode
690 ** information need not be flushed. If the lower four bits of the flag
691 ** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
692 ** If the lower four bits equal SQLITE_SYNC_FULL, that means
693 ** to use Mac OS X style fullsync instead of fsync().
694 **
695 ** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
696 ** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
697 ** settings.  The [synchronous pragma] determines when calls to the
698 ** xSync VFS method occur and applies uniformly across all platforms.
699 ** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
700 ** energetic or rigorous or forceful the sync operations are and
701 ** only make a difference on Mac OSX for the default SQLite code.
702 ** (Third-party VFS implementations might also make the distinction
703 ** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
704 ** operating systems natively supported by SQLite, only Mac OSX
705 ** cares about the difference.)
706 */
707 #define SQLITE_SYNC_NORMAL        0x00002
708 #define SQLITE_SYNC_FULL          0x00003
709 #define SQLITE_SYNC_DATAONLY      0x00010
710 
711 /*
712 ** CAPI3REF: OS Interface Open File Handle
713 **
714 ** An [sqlite3_file] object represents an open file in the
715 ** [sqlite3_vfs | OS interface layer].  Individual OS interface
716 ** implementations will
717 ** want to subclass this object by appending additional fields
718 ** for their own use.  The pMethods entry is a pointer to an
719 ** [sqlite3_io_methods] object that defines methods for performing
720 ** I/O operations on the open file.
721 */
722 typedef struct sqlite3_file sqlite3_file;
723 struct sqlite3_file {
724   const struct sqlite3_io_methods *pMethods;  /* Methods for an open file */
725 };
726 
727 /*
728 ** CAPI3REF: OS Interface File Virtual Methods Object
729 **
730 ** Every file opened by the [sqlite3_vfs.xOpen] method populates an
731 ** [sqlite3_file] object (or, more commonly, a subclass of the
732 ** [sqlite3_file] object) with a pointer to an instance of this object.
733 ** This object defines the methods used to perform various operations
734 ** against the open file represented by the [sqlite3_file] object.
735 **
736 ** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element
737 ** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
738 ** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed.  The
739 ** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
740 ** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
741 ** to NULL.
742 **
743 ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
744 ** [SQLITE_SYNC_FULL].  The first choice is the normal fsync().
745 ** The second choice is a Mac OS X style fullsync.  The [SQLITE_SYNC_DATAONLY]
746 ** flag may be ORed in to indicate that only the data of the file
747 ** and not its inode needs to be synced.
748 **
749 ** The integer values to xLock() and xUnlock() are one of
750 ** <ul>
751 ** <li> [SQLITE_LOCK_NONE],
752 ** <li> [SQLITE_LOCK_SHARED],
753 ** <li> [SQLITE_LOCK_RESERVED],
754 ** <li> [SQLITE_LOCK_PENDING], or
755 ** <li> [SQLITE_LOCK_EXCLUSIVE].
756 ** </ul>
757 ** xLock() increases the lock. xUnlock() decreases the lock.
758 ** The xCheckReservedLock() method checks whether any database connection,
759 ** either in this process or in some other process, is holding a RESERVED,
760 ** PENDING, or EXCLUSIVE lock on the file.  It returns true
761 ** if such a lock exists and false otherwise.
762 **
763 ** The xFileControl() method is a generic interface that allows custom
764 ** VFS implementations to directly control an open file using the
765 ** [sqlite3_file_control()] interface.  The second "op" argument is an
766 ** integer opcode.  The third argument is a generic pointer intended to
767 ** point to a structure that may contain arguments or space in which to
768 ** write return values.  Potential uses for xFileControl() might be
769 ** functions to enable blocking locks with timeouts, to change the
770 ** locking strategy (for example to use dot-file locks), to inquire
771 ** about the status of a lock, or to break stale locks.  The SQLite
772 ** core reserves all opcodes less than 100 for its own use.
773 ** A [file control opcodes | list of opcodes] less than 100 is available.
774 ** Applications that define a custom xFileControl method should use opcodes
775 ** greater than 100 to avoid conflicts.  VFS implementations should
776 ** return [SQLITE_NOTFOUND] for file control opcodes that they do not
777 ** recognize.
778 **
779 ** The xSectorSize() method returns the sector size of the
780 ** device that underlies the file.  The sector size is the
781 ** minimum write that can be performed without disturbing
782 ** other bytes in the file.  The xDeviceCharacteristics()
783 ** method returns a bit vector describing behaviors of the
784 ** underlying device:
785 **
786 ** <ul>
787 ** <li> [SQLITE_IOCAP_ATOMIC]
788 ** <li> [SQLITE_IOCAP_ATOMIC512]
789 ** <li> [SQLITE_IOCAP_ATOMIC1K]
790 ** <li> [SQLITE_IOCAP_ATOMIC2K]
791 ** <li> [SQLITE_IOCAP_ATOMIC4K]
792 ** <li> [SQLITE_IOCAP_ATOMIC8K]
793 ** <li> [SQLITE_IOCAP_ATOMIC16K]
794 ** <li> [SQLITE_IOCAP_ATOMIC32K]
795 ** <li> [SQLITE_IOCAP_ATOMIC64K]
796 ** <li> [SQLITE_IOCAP_SAFE_APPEND]
797 ** <li> [SQLITE_IOCAP_SEQUENTIAL]
798 ** <li> [SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN]
799 ** <li> [SQLITE_IOCAP_POWERSAFE_OVERWRITE]
800 ** <li> [SQLITE_IOCAP_IMMUTABLE]
801 ** <li> [SQLITE_IOCAP_BATCH_ATOMIC]
802 ** </ul>
803 **
804 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
805 ** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
806 ** mean that writes of blocks that are nnn bytes in size and
807 ** are aligned to an address which is an integer multiple of
808 ** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
809 ** that when data is appended to a file, the data is appended
810 ** first then the size of the file is extended, never the other
811 ** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
812 ** information is written to disk in the same order as calls
813 ** to xWrite().
814 **
815 ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
816 ** in the unread portions of the buffer with zeros.  A VFS that
817 ** fails to zero-fill short reads might seem to work.  However,
818 ** failure to zero-fill short reads will eventually lead to
819 ** database corruption.
820 */
821 typedef struct sqlite3_io_methods sqlite3_io_methods;
822 struct sqlite3_io_methods {
823   int iVersion;
824   int (*xClose)(sqlite3_file*);
825   int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
826   int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
827   int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
828   int (*xSync)(sqlite3_file*, int flags);
829   int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
830   int (*xLock)(sqlite3_file*, int);
831   int (*xUnlock)(sqlite3_file*, int);
832   int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
833   int (*xFileControl)(sqlite3_file*, int op, void *pArg);
834   int (*xSectorSize)(sqlite3_file*);
835   int (*xDeviceCharacteristics)(sqlite3_file*);
836   /* Methods above are valid for version 1 */
837   int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
838   int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
839   void (*xShmBarrier)(sqlite3_file*);
840   int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
841   /* Methods above are valid for version 2 */
842   int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp);
843   int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p);
844   /* Methods above are valid for version 3 */
845   /* Additional methods may be added in future releases */
846 };
847 
848 /*
849 ** CAPI3REF: Standard File Control Opcodes
850 ** KEYWORDS: {file control opcodes} {file control opcode}
851 **
852 ** These integer constants are opcodes for the xFileControl method
853 ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
854 ** interface.
855 **
856 ** <ul>
857 ** <li>[[SQLITE_FCNTL_LOCKSTATE]]
858 ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging.  This
859 ** opcode causes the xFileControl method to write the current state of
860 ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
861 ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
862 ** into an integer that the pArg argument points to. This capability
863 ** is used during testing and is only available when the SQLITE_TEST
864 ** compile-time option is used.
865 **
866 ** <li>[[SQLITE_FCNTL_SIZE_HINT]]
867 ** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
868 ** layer a hint of how large the database file will grow to be during the
869 ** current transaction.  This hint is not guaranteed to be accurate but it
870 ** is often close.  The underlying VFS might choose to preallocate database
871 ** file space based on this hint in order to help writes to the database
872 ** file run faster.
873 **
874 ** <li>[[SQLITE_FCNTL_SIZE_LIMIT]]
875 ** The [SQLITE_FCNTL_SIZE_LIMIT] opcode is used by in-memory VFS that
876 ** implements [sqlite3_deserialize()] to set an upper bound on the size
877 ** of the in-memory database.  The argument is a pointer to a [sqlite3_int64].
878 ** If the integer pointed to is negative, then it is filled in with the
879 ** current limit.  Otherwise the limit is set to the larger of the value
880 ** of the integer pointed to and the current database size.  The integer
881 ** pointed to is set to the new limit.
882 **
883 ** <li>[[SQLITE_FCNTL_CHUNK_SIZE]]
884 ** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
885 ** extends and truncates the database file in chunks of a size specified
886 ** by the user. The fourth argument to [sqlite3_file_control()] should
887 ** point to an integer (type int) containing the new chunk-size to use
888 ** for the nominated database. Allocating database file space in large
889 ** chunks (say 1MB at a time), may reduce file-system fragmentation and
890 ** improve performance on some systems.
891 **
892 ** <li>[[SQLITE_FCNTL_FILE_POINTER]]
893 ** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
894 ** to the [sqlite3_file] object associated with a particular database
895 ** connection.  See also [SQLITE_FCNTL_JOURNAL_POINTER].
896 **
897 ** <li>[[SQLITE_FCNTL_JOURNAL_POINTER]]
898 ** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer
899 ** to the [sqlite3_file] object associated with the journal file (either
900 ** the [rollback journal] or the [write-ahead log]) for a particular database
901 ** connection.  See also [SQLITE_FCNTL_FILE_POINTER].
902 **
903 ** <li>[[SQLITE_FCNTL_SYNC_OMITTED]]
904 ** No longer in use.
905 **
906 ** <li>[[SQLITE_FCNTL_SYNC]]
907 ** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and
908 ** sent to the VFS immediately before the xSync method is invoked on a
909 ** database file descriptor. Or, if the xSync method is not invoked
910 ** because the user has configured SQLite with
911 ** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place
912 ** of the xSync method. In most cases, the pointer argument passed with
913 ** this file-control is NULL. However, if the database file is being synced
914 ** as part of a multi-database commit, the argument points to a nul-terminated
915 ** string containing the transactions super-journal file name. VFSes that
916 ** do not need this signal should silently ignore this opcode. Applications
917 ** should not call [sqlite3_file_control()] with this opcode as doing so may
918 ** disrupt the operation of the specialized VFSes that do require it.
919 **
920 ** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]]
921 ** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite
922 ** and sent to the VFS after a transaction has been committed immediately
923 ** but before the database is unlocked. VFSes that do not need this signal
924 ** should silently ignore this opcode. Applications should not call
925 ** [sqlite3_file_control()] with this opcode as doing so may disrupt the
926 ** operation of the specialized VFSes that do require it.
927 **
928 ** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]]
929 ** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
930 ** retry counts and intervals for certain disk I/O operations for the
931 ** windows [VFS] in order to provide robustness in the presence of
932 ** anti-virus programs.  By default, the windows VFS will retry file read,
933 ** file write, and file delete operations up to 10 times, with a delay
934 ** of 25 milliseconds before the first retry and with the delay increasing
935 ** by an additional 25 milliseconds with each subsequent retry.  This
936 ** opcode allows these two values (10 retries and 25 milliseconds of delay)
937 ** to be adjusted.  The values are changed for all database connections
938 ** within the same process.  The argument is a pointer to an array of two
939 ** integers where the first integer is the new retry count and the second
940 ** integer is the delay.  If either integer is negative, then the setting
941 ** is not changed but instead the prior value of that setting is written
942 ** into the array entry, allowing the current retry settings to be
943 ** interrogated.  The zDbName parameter is ignored.
944 **
945 ** <li>[[SQLITE_FCNTL_PERSIST_WAL]]
946 ** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
947 ** persistent [WAL | Write Ahead Log] setting.  By default, the auxiliary
948 ** write ahead log ([WAL file]) and shared memory
949 ** files used for transaction control
950 ** are automatically deleted when the latest connection to the database
951 ** closes.  Setting persistent WAL mode causes those files to persist after
952 ** close.  Persisting the files is useful when other processes that do not
953 ** have write permission on the directory containing the database file want
954 ** to read the database file, as the WAL and shared memory files must exist
955 ** in order for the database to be readable.  The fourth parameter to
956 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
957 ** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
958 ** WAL mode.  If the integer is -1, then it is overwritten with the current
959 ** WAL persistence setting.
960 **
961 ** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]]
962 ** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
963 ** persistent "powersafe-overwrite" or "PSOW" setting.  The PSOW setting
964 ** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
965 ** xDeviceCharacteristics methods. The fourth parameter to
966 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
967 ** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
968 ** mode.  If the integer is -1, then it is overwritten with the current
969 ** zero-damage mode setting.
970 **
971 ** <li>[[SQLITE_FCNTL_OVERWRITE]]
972 ** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
973 ** a write transaction to indicate that, unless it is rolled back for some
974 ** reason, the entire database file will be overwritten by the current
975 ** transaction. This is used by VACUUM operations.
976 **
977 ** <li>[[SQLITE_FCNTL_VFSNAME]]
978 ** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
979 ** all [VFSes] in the VFS stack.  The names are of all VFS shims and the
980 ** final bottom-level VFS are written into memory obtained from
981 ** [sqlite3_malloc()] and the result is stored in the char* variable
982 ** that the fourth parameter of [sqlite3_file_control()] points to.
983 ** The caller is responsible for freeing the memory when done.  As with
984 ** all file-control actions, there is no guarantee that this will actually
985 ** do anything.  Callers should initialize the char* variable to a NULL
986 ** pointer in case this file-control is not implemented.  This file-control
987 ** is intended for diagnostic use only.
988 **
989 ** <li>[[SQLITE_FCNTL_VFS_POINTER]]
990 ** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level
991 ** [VFSes] currently in use.  ^(The argument X in
992 ** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be
993 ** of type "[sqlite3_vfs] **".  This opcodes will set *X
994 ** to a pointer to the top-level VFS.)^
995 ** ^When there are multiple VFS shims in the stack, this opcode finds the
996 ** upper-most shim only.
997 **
998 ** <li>[[SQLITE_FCNTL_PRAGMA]]
999 ** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA]
1000 ** file control is sent to the open [sqlite3_file] object corresponding
1001 ** to the database file to which the pragma statement refers. ^The argument
1002 ** to the [SQLITE_FCNTL_PRAGMA] file control is an array of
1003 ** pointers to strings (char**) in which the second element of the array
1004 ** is the name of the pragma and the third element is the argument to the
1005 ** pragma or NULL if the pragma has no argument.  ^The handler for an
1006 ** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element
1007 ** of the char** argument point to a string obtained from [sqlite3_mprintf()]
1008 ** or the equivalent and that string will become the result of the pragma or
1009 ** the error message if the pragma fails. ^If the
1010 ** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal
1011 ** [PRAGMA] processing continues.  ^If the [SQLITE_FCNTL_PRAGMA]
1012 ** file control returns [SQLITE_OK], then the parser assumes that the
1013 ** VFS has handled the PRAGMA itself and the parser generates a no-op
1014 ** prepared statement if result string is NULL, or that returns a copy
1015 ** of the result string if the string is non-NULL.
1016 ** ^If the [SQLITE_FCNTL_PRAGMA] file control returns
1017 ** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means
1018 ** that the VFS encountered an error while handling the [PRAGMA] and the
1019 ** compilation of the PRAGMA fails with an error.  ^The [SQLITE_FCNTL_PRAGMA]
1020 ** file control occurs at the beginning of pragma statement analysis and so
1021 ** it is able to override built-in [PRAGMA] statements.
1022 **
1023 ** <li>[[SQLITE_FCNTL_BUSYHANDLER]]
1024 ** ^The [SQLITE_FCNTL_BUSYHANDLER]
1025 ** file-control may be invoked by SQLite on the database file handle
1026 ** shortly after it is opened in order to provide a custom VFS with access
1027 ** to the connection's busy-handler callback. The argument is of type (void**)
1028 ** - an array of two (void *) values. The first (void *) actually points
1029 ** to a function of type (int (*)(void *)). In order to invoke the connection's
1030 ** busy-handler, this function should be invoked with the second (void *) in
1031 ** the array as the only argument. If it returns non-zero, then the operation
1032 ** should be retried. If it returns zero, the custom VFS should abandon the
1033 ** current operation.
1034 **
1035 ** <li>[[SQLITE_FCNTL_TEMPFILENAME]]
1036 ** ^Applications can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control
1037 ** to have SQLite generate a
1038 ** temporary filename using the same algorithm that is followed to generate
1039 ** temporary filenames for TEMP tables and other internal uses.  The
1040 ** argument should be a char** which will be filled with the filename
1041 ** written into memory obtained from [sqlite3_malloc()].  The caller should
1042 ** invoke [sqlite3_free()] on the result to avoid a memory leak.
1043 **
1044 ** <li>[[SQLITE_FCNTL_MMAP_SIZE]]
1045 ** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the
1046 ** maximum number of bytes that will be used for memory-mapped I/O.
1047 ** The argument is a pointer to a value of type sqlite3_int64 that
1048 ** is an advisory maximum number of bytes in the file to memory map.  The
1049 ** pointer is overwritten with the old value.  The limit is not changed if
1050 ** the value originally pointed to is negative, and so the current limit
1051 ** can be queried by passing in a pointer to a negative number.  This
1052 ** file-control is used internally to implement [PRAGMA mmap_size].
1053 **
1054 ** <li>[[SQLITE_FCNTL_TRACE]]
1055 ** The [SQLITE_FCNTL_TRACE] file control provides advisory information
1056 ** to the VFS about what the higher layers of the SQLite stack are doing.
1057 ** This file control is used by some VFS activity tracing [shims].
1058 ** The argument is a zero-terminated string.  Higher layers in the
1059 ** SQLite stack may generate instances of this file control if
1060 ** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled.
1061 **
1062 ** <li>[[SQLITE_FCNTL_HAS_MOVED]]
1063 ** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a
1064 ** pointer to an integer and it writes a boolean into that integer depending
1065 ** on whether or not the file has been renamed, moved, or deleted since it
1066 ** was first opened.
1067 **
1068 ** <li>[[SQLITE_FCNTL_WIN32_GET_HANDLE]]
1069 ** The [SQLITE_FCNTL_WIN32_GET_HANDLE] opcode can be used to obtain the
1070 ** underlying native file handle associated with a file handle.  This file
1071 ** control interprets its argument as a pointer to a native file handle and
1072 ** writes the resulting value there.
1073 **
1074 ** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]]
1075 ** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging.  This
1076 ** opcode causes the xFileControl method to swap the file handle with the one
1077 ** pointed to by the pArg argument.  This capability is used during testing
1078 ** and only needs to be supported when SQLITE_TEST is defined.
1079 **
1080 ** <li>[[SQLITE_FCNTL_WAL_BLOCK]]
1081 ** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might
1082 ** be advantageous to block on the next WAL lock if the lock is not immediately
1083 ** available.  The WAL subsystem issues this signal during rare
1084 ** circumstances in order to fix a problem with priority inversion.
1085 ** Applications should <em>not</em> use this file-control.
1086 **
1087 ** <li>[[SQLITE_FCNTL_ZIPVFS]]
1088 ** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other
1089 ** VFS should return SQLITE_NOTFOUND for this opcode.
1090 **
1091 ** <li>[[SQLITE_FCNTL_RBU]]
1092 ** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by
1093 ** the RBU extension only.  All other VFS should return SQLITE_NOTFOUND for
1094 ** this opcode.
1095 **
1096 ** <li>[[SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]]
1097 ** If the [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] opcode returns SQLITE_OK, then
1098 ** the file descriptor is placed in "batch write mode", which
1099 ** means all subsequent write operations will be deferred and done
1100 ** atomically at the next [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE].  Systems
1101 ** that do not support batch atomic writes will return SQLITE_NOTFOUND.
1102 ** ^Following a successful SQLITE_FCNTL_BEGIN_ATOMIC_WRITE and prior to
1103 ** the closing [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] or
1104 ** [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE], SQLite will make
1105 ** no VFS interface calls on the same [sqlite3_file] file descriptor
1106 ** except for calls to the xWrite method and the xFileControl method
1107 ** with [SQLITE_FCNTL_SIZE_HINT].
1108 **
1109 ** <li>[[SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]]
1110 ** The [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] opcode causes all write
1111 ** operations since the previous successful call to
1112 ** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be performed atomically.
1113 ** This file control returns [SQLITE_OK] if and only if the writes were
1114 ** all performed successfully and have been committed to persistent storage.
1115 ** ^Regardless of whether or not it is successful, this file control takes
1116 ** the file descriptor out of batch write mode so that all subsequent
1117 ** write operations are independent.
1118 ** ^SQLite will never invoke SQLITE_FCNTL_COMMIT_ATOMIC_WRITE without
1119 ** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE].
1120 **
1121 ** <li>[[SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE]]
1122 ** The [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE] opcode causes all write
1123 ** operations since the previous successful call to
1124 ** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be rolled back.
1125 ** ^This file control takes the file descriptor out of batch write mode
1126 ** so that all subsequent write operations are independent.
1127 ** ^SQLite will never invoke SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE without
1128 ** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE].
1129 **
1130 ** <li>[[SQLITE_FCNTL_LOCK_TIMEOUT]]
1131 ** The [SQLITE_FCNTL_LOCK_TIMEOUT] opcode is used to configure a VFS
1132 ** to block for up to M milliseconds before failing when attempting to
1133 ** obtain a file lock using the xLock or xShmLock methods of the VFS.
1134 ** The parameter is a pointer to a 32-bit signed integer that contains
1135 ** the value that M is to be set to. Before returning, the 32-bit signed
1136 ** integer is overwritten with the previous value of M.
1137 **
1138 ** <li>[[SQLITE_FCNTL_DATA_VERSION]]
1139 ** The [SQLITE_FCNTL_DATA_VERSION] opcode is used to detect changes to
1140 ** a database file.  The argument is a pointer to a 32-bit unsigned integer.
1141 ** The "data version" for the pager is written into the pointer.  The
1142 ** "data version" changes whenever any change occurs to the corresponding
1143 ** database file, either through SQL statements on the same database
1144 ** connection or through transactions committed by separate database
1145 ** connections possibly in other processes. The [sqlite3_total_changes()]
1146 ** interface can be used to find if any database on the connection has changed,
1147 ** but that interface responds to changes on TEMP as well as MAIN and does
1148 ** not provide a mechanism to detect changes to MAIN only.  Also, the
1149 ** [sqlite3_total_changes()] interface responds to internal changes only and
1150 ** omits changes made by other database connections.  The
1151 ** [PRAGMA data_version] command provides a mechanism to detect changes to
1152 ** a single attached database that occur due to other database connections,
1153 ** but omits changes implemented by the database connection on which it is
1154 ** called.  This file control is the only mechanism to detect changes that
1155 ** happen either internally or externally and that are associated with
1156 ** a particular attached database.
1157 **
1158 ** <li>[[SQLITE_FCNTL_CKPT_START]]
1159 ** The [SQLITE_FCNTL_CKPT_START] opcode is invoked from within a checkpoint
1160 ** in wal mode before the client starts to copy pages from the wal
1161 ** file to the database file.
1162 **
1163 ** <li>[[SQLITE_FCNTL_CKPT_DONE]]
1164 ** The [SQLITE_FCNTL_CKPT_DONE] opcode is invoked from within a checkpoint
1165 ** in wal mode after the client has finished copying pages from the wal
1166 ** file to the database file, but before the *-shm file is updated to
1167 ** record the fact that the pages have been checkpointed.
1168 ** </ul>
1169 **
1170 ** <li>[[SQLITE_FCNTL_EXTERNAL_READER]]
1171 ** The EXPERIMENTAL [SQLITE_FCNTL_EXTERNAL_READER] opcode is used to detect
1172 ** whether or not there is a database client in another process with a wal-mode
1173 ** transaction open on the database or not. It is only available on unix.The
1174 ** (void*) argument passed with this file-control should be a pointer to a
1175 ** value of type (int). The integer value is set to 1 if the database is a wal
1176 ** mode database and there exists at least one client in another process that
1177 ** currently has an SQL transaction open on the database. It is set to 0 if
1178 ** the database is not a wal-mode db, or if there is no such connection in any
1179 ** other process. This opcode cannot be used to detect transactions opened
1180 ** by clients within the current process, only within other processes.
1181 ** </ul>
1182 **
1183 ** <li>[[SQLITE_FCNTL_CKSM_FILE]]
1184 ** Used by the cksmvfs VFS module only.
1185 ** </ul>
1186 */
1187 #define SQLITE_FCNTL_LOCKSTATE               1
1188 #define SQLITE_FCNTL_GET_LOCKPROXYFILE       2
1189 #define SQLITE_FCNTL_SET_LOCKPROXYFILE       3
1190 #define SQLITE_FCNTL_LAST_ERRNO              4
1191 #define SQLITE_FCNTL_SIZE_HINT               5
1192 #define SQLITE_FCNTL_CHUNK_SIZE              6
1193 #define SQLITE_FCNTL_FILE_POINTER            7
1194 #define SQLITE_FCNTL_SYNC_OMITTED            8
1195 #define SQLITE_FCNTL_WIN32_AV_RETRY          9
1196 #define SQLITE_FCNTL_PERSIST_WAL            10
1197 #define SQLITE_FCNTL_OVERWRITE              11
1198 #define SQLITE_FCNTL_VFSNAME                12
1199 #define SQLITE_FCNTL_POWERSAFE_OVERWRITE    13
1200 #define SQLITE_FCNTL_PRAGMA                 14
1201 #define SQLITE_FCNTL_BUSYHANDLER            15
1202 #define SQLITE_FCNTL_TEMPFILENAME           16
1203 #define SQLITE_FCNTL_MMAP_SIZE              18
1204 #define SQLITE_FCNTL_TRACE                  19
1205 #define SQLITE_FCNTL_HAS_MOVED              20
1206 #define SQLITE_FCNTL_SYNC                   21
1207 #define SQLITE_FCNTL_COMMIT_PHASETWO        22
1208 #define SQLITE_FCNTL_WIN32_SET_HANDLE       23
1209 #define SQLITE_FCNTL_WAL_BLOCK              24
1210 #define SQLITE_FCNTL_ZIPVFS                 25
1211 #define SQLITE_FCNTL_RBU                    26
1212 #define SQLITE_FCNTL_VFS_POINTER            27
1213 #define SQLITE_FCNTL_JOURNAL_POINTER        28
1214 #define SQLITE_FCNTL_WIN32_GET_HANDLE       29
1215 #define SQLITE_FCNTL_PDB                    30
1216 #define SQLITE_FCNTL_BEGIN_ATOMIC_WRITE     31
1217 #define SQLITE_FCNTL_COMMIT_ATOMIC_WRITE    32
1218 #define SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE  33
1219 #define SQLITE_FCNTL_LOCK_TIMEOUT           34
1220 #define SQLITE_FCNTL_DATA_VERSION           35
1221 #define SQLITE_FCNTL_SIZE_LIMIT             36
1222 #define SQLITE_FCNTL_CKPT_DONE              37
1223 #define SQLITE_FCNTL_RESERVE_BYTES          38
1224 #define SQLITE_FCNTL_CKPT_START             39
1225 #define SQLITE_FCNTL_EXTERNAL_READER        40
1226 #define SQLITE_FCNTL_CKSM_FILE              41
1227 
1228 /* deprecated names */
1229 #define SQLITE_GET_LOCKPROXYFILE      SQLITE_FCNTL_GET_LOCKPROXYFILE
1230 #define SQLITE_SET_LOCKPROXYFILE      SQLITE_FCNTL_SET_LOCKPROXYFILE
1231 #define SQLITE_LAST_ERRNO             SQLITE_FCNTL_LAST_ERRNO
1232 
1233 
1234 /*
1235 ** CAPI3REF: Mutex Handle
1236 **
1237 ** The mutex module within SQLite defines [sqlite3_mutex] to be an
1238 ** abstract type for a mutex object.  The SQLite core never looks
1239 ** at the internal representation of an [sqlite3_mutex].  It only
1240 ** deals with pointers to the [sqlite3_mutex] object.
1241 **
1242 ** Mutexes are created using [sqlite3_mutex_alloc()].
1243 */
1244 typedef struct sqlite3_mutex sqlite3_mutex;
1245 
1246 /*
1247 ** CAPI3REF: Loadable Extension Thunk
1248 **
1249 ** A pointer to the opaque sqlite3_api_routines structure is passed as
1250 ** the third parameter to entry points of [loadable extensions].  This
1251 ** structure must be typedefed in order to work around compiler warnings
1252 ** on some platforms.
1253 */
1254 typedef struct sqlite3_api_routines sqlite3_api_routines;
1255 
1256 /*
1257 ** CAPI3REF: OS Interface Object
1258 **
1259 ** An instance of the sqlite3_vfs object defines the interface between
1260 ** the SQLite core and the underlying operating system.  The "vfs"
1261 ** in the name of the object stands for "virtual file system".  See
1262 ** the [VFS | VFS documentation] for further information.
1263 **
1264 ** The VFS interface is sometimes extended by adding new methods onto
1265 ** the end.  Each time such an extension occurs, the iVersion field
1266 ** is incremented.  The iVersion value started out as 1 in
1267 ** SQLite [version 3.5.0] on [dateof:3.5.0], then increased to 2
1268 ** with SQLite [version 3.7.0] on [dateof:3.7.0], and then increased
1269 ** to 3 with SQLite [version 3.7.6] on [dateof:3.7.6].  Additional fields
1270 ** may be appended to the sqlite3_vfs object and the iVersion value
1271 ** may increase again in future versions of SQLite.
1272 ** Note that due to an oversight, the structure
1273 ** of the sqlite3_vfs object changed in the transition from
1274 ** SQLite [version 3.5.9] to [version 3.6.0] on [dateof:3.6.0]
1275 ** and yet the iVersion field was not increased.
1276 **
1277 ** The szOsFile field is the size of the subclassed [sqlite3_file]
1278 ** structure used by this VFS.  mxPathname is the maximum length of
1279 ** a pathname in this VFS.
1280 **
1281 ** Registered sqlite3_vfs objects are kept on a linked list formed by
1282 ** the pNext pointer.  The [sqlite3_vfs_register()]
1283 ** and [sqlite3_vfs_unregister()] interfaces manage this list
1284 ** in a thread-safe way.  The [sqlite3_vfs_find()] interface
1285 ** searches the list.  Neither the application code nor the VFS
1286 ** implementation should use the pNext pointer.
1287 **
1288 ** The pNext field is the only field in the sqlite3_vfs
1289 ** structure that SQLite will ever modify.  SQLite will only access
1290 ** or modify this field while holding a particular static mutex.
1291 ** The application should never modify anything within the sqlite3_vfs
1292 ** object once the object has been registered.
1293 **
1294 ** The zName field holds the name of the VFS module.  The name must
1295 ** be unique across all VFS modules.
1296 **
1297 ** [[sqlite3_vfs.xOpen]]
1298 ** ^SQLite guarantees that the zFilename parameter to xOpen
1299 ** is either a NULL pointer or string obtained
1300 ** from xFullPathname() with an optional suffix added.
1301 ** ^If a suffix is added to the zFilename parameter, it will
1302 ** consist of a single "-" character followed by no more than
1303 ** 11 alphanumeric and/or "-" characters.
1304 ** ^SQLite further guarantees that
1305 ** the string will be valid and unchanged until xClose() is
1306 ** called. Because of the previous sentence,
1307 ** the [sqlite3_file] can safely store a pointer to the
1308 ** filename if it needs to remember the filename for some reason.
1309 ** If the zFilename parameter to xOpen is a NULL pointer then xOpen
1310 ** must invent its own temporary name for the file.  ^Whenever the
1311 ** xFilename parameter is NULL it will also be the case that the
1312 ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
1313 **
1314 ** The flags argument to xOpen() includes all bits set in
1315 ** the flags argument to [sqlite3_open_v2()].  Or if [sqlite3_open()]
1316 ** or [sqlite3_open16()] is used, then flags includes at least
1317 ** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE].
1318 ** If xOpen() opens a file read-only then it sets *pOutFlags to
1319 ** include [SQLITE_OPEN_READONLY].  Other bits in *pOutFlags may be set.
1320 **
1321 ** ^(SQLite will also add one of the following flags to the xOpen()
1322 ** call, depending on the object being opened:
1323 **
1324 ** <ul>
1325 ** <li>  [SQLITE_OPEN_MAIN_DB]
1326 ** <li>  [SQLITE_OPEN_MAIN_JOURNAL]
1327 ** <li>  [SQLITE_OPEN_TEMP_DB]
1328 ** <li>  [SQLITE_OPEN_TEMP_JOURNAL]
1329 ** <li>  [SQLITE_OPEN_TRANSIENT_DB]
1330 ** <li>  [SQLITE_OPEN_SUBJOURNAL]
1331 ** <li>  [SQLITE_OPEN_SUPER_JOURNAL]
1332 ** <li>  [SQLITE_OPEN_WAL]
1333 ** </ul>)^
1334 **
1335 ** The file I/O implementation can use the object type flags to
1336 ** change the way it deals with files.  For example, an application
1337 ** that does not care about crash recovery or rollback might make
1338 ** the open of a journal file a no-op.  Writes to this journal would
1339 ** also be no-ops, and any attempt to read the journal would return
1340 ** SQLITE_IOERR.  Or the implementation might recognize that a database
1341 ** file will be doing page-aligned sector reads and writes in a random
1342 ** order and set up its I/O subsystem accordingly.
1343 **
1344 ** SQLite might also add one of the following flags to the xOpen method:
1345 **
1346 ** <ul>
1347 ** <li> [SQLITE_OPEN_DELETEONCLOSE]
1348 ** <li> [SQLITE_OPEN_EXCLUSIVE]
1349 ** </ul>
1350 **
1351 ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
1352 ** deleted when it is closed.  ^The [SQLITE_OPEN_DELETEONCLOSE]
1353 ** will be set for TEMP databases and their journals, transient
1354 ** databases, and subjournals.
1355 **
1356 ** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
1357 ** with the [SQLITE_OPEN_CREATE] flag, which are both directly
1358 ** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
1359 ** API.  The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
1360 ** SQLITE_OPEN_CREATE, is used to indicate that file should always
1361 ** be created, and that it is an error if it already exists.
1362 ** It is <i>not</i> used to indicate the file should be opened
1363 ** for exclusive access.
1364 **
1365 ** ^At least szOsFile bytes of memory are allocated by SQLite
1366 ** to hold the [sqlite3_file] structure passed as the third
1367 ** argument to xOpen.  The xOpen method does not have to
1368 ** allocate the structure; it should just fill it in.  Note that
1369 ** the xOpen method must set the sqlite3_file.pMethods to either
1370 ** a valid [sqlite3_io_methods] object or to NULL.  xOpen must do
1371 ** this even if the open fails.  SQLite expects that the sqlite3_file.pMethods
1372 ** element will be valid after xOpen returns regardless of the success
1373 ** or failure of the xOpen call.
1374 **
1375 ** [[sqlite3_vfs.xAccess]]
1376 ** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
1377 ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
1378 ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
1379 ** to test whether a file is at least readable.  The SQLITE_ACCESS_READ
1380 ** flag is never actually used and is not implemented in the built-in
1381 ** VFSes of SQLite.  The file is named by the second argument and can be a
1382 ** directory. The xAccess method returns [SQLITE_OK] on success or some
1383 ** non-zero error code if there is an I/O error or if the name of
1384 ** the file given in the second argument is illegal.  If SQLITE_OK
1385 ** is returned, then non-zero or zero is written into *pResOut to indicate
1386 ** whether or not the file is accessible.
1387 **
1388 ** ^SQLite will always allocate at least mxPathname+1 bytes for the
1389 ** output buffer xFullPathname.  The exact size of the output buffer
1390 ** is also passed as a parameter to both  methods. If the output buffer
1391 ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
1392 ** handled as a fatal error by SQLite, vfs implementations should endeavor
1393 ** to prevent this by setting mxPathname to a sufficiently large value.
1394 **
1395 ** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
1396 ** interfaces are not strictly a part of the filesystem, but they are
1397 ** included in the VFS structure for completeness.
1398 ** The xRandomness() function attempts to return nBytes bytes
1399 ** of good-quality randomness into zOut.  The return value is
1400 ** the actual number of bytes of randomness obtained.
1401 ** The xSleep() method causes the calling thread to sleep for at
1402 ** least the number of microseconds given.  ^The xCurrentTime()
1403 ** method returns a Julian Day Number for the current date and time as
1404 ** a floating point value.
1405 ** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
1406 ** Day Number multiplied by 86400000 (the number of milliseconds in
1407 ** a 24-hour day).
1408 ** ^SQLite will use the xCurrentTimeInt64() method to get the current
1409 ** date and time if that method is available (if iVersion is 2 or
1410 ** greater and the function pointer is not NULL) and will fall back
1411 ** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
1412 **
1413 ** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
1414 ** are not used by the SQLite core.  These optional interfaces are provided
1415 ** by some VFSes to facilitate testing of the VFS code. By overriding
1416 ** system calls with functions under its control, a test program can
1417 ** simulate faults and error conditions that would otherwise be difficult
1418 ** or impossible to induce.  The set of system calls that can be overridden
1419 ** varies from one VFS to another, and from one version of the same VFS to the
1420 ** next.  Applications that use these interfaces must be prepared for any
1421 ** or all of these interfaces to be NULL or for their behavior to change
1422 ** from one release to the next.  Applications must not attempt to access
1423 ** any of these methods if the iVersion of the VFS is less than 3.
1424 */
1425 typedef struct sqlite3_vfs sqlite3_vfs;
1426 typedef void (*sqlite3_syscall_ptr)(void);
1427 struct sqlite3_vfs {
1428   int iVersion;            /* Structure version number (currently 3) */
1429   int szOsFile;            /* Size of subclassed sqlite3_file */
1430   int mxPathname;          /* Maximum file pathname length */
1431   sqlite3_vfs *pNext;      /* Next registered VFS */
1432   const char *zName;       /* Name of this virtual file system */
1433   void *pAppData;          /* Pointer to application-specific data */
1434   int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
1435                int flags, int *pOutFlags);
1436   int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
1437   int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
1438   int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
1439   void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
1440   void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
1441   void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
1442   void (*xDlClose)(sqlite3_vfs*, void*);
1443   int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
1444   int (*xSleep)(sqlite3_vfs*, int microseconds);
1445   int (*xCurrentTime)(sqlite3_vfs*, double*);
1446   int (*xGetLastError)(sqlite3_vfs*, int, char *);
1447   /*
1448   ** The methods above are in version 1 of the sqlite_vfs object
1449   ** definition.  Those that follow are added in version 2 or later
1450   */
1451   int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
1452   /*
1453   ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
1454   ** Those below are for version 3 and greater.
1455   */
1456   int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
1457   sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
1458   const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
1459   /*
1460   ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
1461   ** New fields may be appended in future versions.  The iVersion
1462   ** value will increment whenever this happens.
1463   */
1464 };
1465 
1466 /*
1467 ** CAPI3REF: Flags for the xAccess VFS method
1468 **
1469 ** These integer constants can be used as the third parameter to
1470 ** the xAccess method of an [sqlite3_vfs] object.  They determine
1471 ** what kind of permissions the xAccess method is looking for.
1472 ** With SQLITE_ACCESS_EXISTS, the xAccess method
1473 ** simply checks whether the file exists.
1474 ** With SQLITE_ACCESS_READWRITE, the xAccess method
1475 ** checks whether the named directory is both readable and writable
1476 ** (in other words, if files can be added, removed, and renamed within
1477 ** the directory).
1478 ** The SQLITE_ACCESS_READWRITE constant is currently used only by the
1479 ** [temp_store_directory pragma], though this could change in a future
1480 ** release of SQLite.
1481 ** With SQLITE_ACCESS_READ, the xAccess method
1482 ** checks whether the file is readable.  The SQLITE_ACCESS_READ constant is
1483 ** currently unused, though it might be used in a future release of
1484 ** SQLite.
1485 */
1486 #define SQLITE_ACCESS_EXISTS    0
1487 #define SQLITE_ACCESS_READWRITE 1   /* Used by PRAGMA temp_store_directory */
1488 #define SQLITE_ACCESS_READ      2   /* Unused */
1489 
1490 /*
1491 ** CAPI3REF: Flags for the xShmLock VFS method
1492 **
1493 ** These integer constants define the various locking operations
1494 ** allowed by the xShmLock method of [sqlite3_io_methods].  The
1495 ** following are the only legal combinations of flags to the
1496 ** xShmLock method:
1497 **
1498 ** <ul>
1499 ** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
1500 ** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
1501 ** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
1502 ** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
1503 ** </ul>
1504 **
1505 ** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
1506 ** was given on the corresponding lock.
1507 **
1508 ** The xShmLock method can transition between unlocked and SHARED or
1509 ** between unlocked and EXCLUSIVE.  It cannot transition between SHARED
1510 ** and EXCLUSIVE.
1511 */
1512 #define SQLITE_SHM_UNLOCK       1
1513 #define SQLITE_SHM_LOCK         2
1514 #define SQLITE_SHM_SHARED       4
1515 #define SQLITE_SHM_EXCLUSIVE    8
1516 
1517 /*
1518 ** CAPI3REF: Maximum xShmLock index
1519 **
1520 ** The xShmLock method on [sqlite3_io_methods] may use values
1521 ** between 0 and this upper bound as its "offset" argument.
1522 ** The SQLite core will never attempt to acquire or release a
1523 ** lock outside of this range
1524 */
1525 #define SQLITE_SHM_NLOCK        8
1526 
1527 
1528 /*
1529 ** CAPI3REF: Initialize The SQLite Library
1530 **
1531 ** ^The sqlite3_initialize() routine initializes the
1532 ** SQLite library.  ^The sqlite3_shutdown() routine
1533 ** deallocates any resources that were allocated by sqlite3_initialize().
1534 ** These routines are designed to aid in process initialization and
1535 ** shutdown on embedded systems.  Workstation applications using
1536 ** SQLite normally do not need to invoke either of these routines.
1537 **
1538 ** A call to sqlite3_initialize() is an "effective" call if it is
1539 ** the first time sqlite3_initialize() is invoked during the lifetime of
1540 ** the process, or if it is the first time sqlite3_initialize() is invoked
1541 ** following a call to sqlite3_shutdown().  ^(Only an effective call
1542 ** of sqlite3_initialize() does any initialization.  All other calls
1543 ** are harmless no-ops.)^
1544 **
1545 ** A call to sqlite3_shutdown() is an "effective" call if it is the first
1546 ** call to sqlite3_shutdown() since the last sqlite3_initialize().  ^(Only
1547 ** an effective call to sqlite3_shutdown() does any deinitialization.
1548 ** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
1549 **
1550 ** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
1551 ** is not.  The sqlite3_shutdown() interface must only be called from a
1552 ** single thread.  All open [database connections] must be closed and all
1553 ** other SQLite resources must be deallocated prior to invoking
1554 ** sqlite3_shutdown().
1555 **
1556 ** Among other things, ^sqlite3_initialize() will invoke
1557 ** sqlite3_os_init().  Similarly, ^sqlite3_shutdown()
1558 ** will invoke sqlite3_os_end().
1559 **
1560 ** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
1561 ** ^If for some reason, sqlite3_initialize() is unable to initialize
1562 ** the library (perhaps it is unable to allocate a needed resource such
1563 ** as a mutex) it returns an [error code] other than [SQLITE_OK].
1564 **
1565 ** ^The sqlite3_initialize() routine is called internally by many other
1566 ** SQLite interfaces so that an application usually does not need to
1567 ** invoke sqlite3_initialize() directly.  For example, [sqlite3_open()]
1568 ** calls sqlite3_initialize() so the SQLite library will be automatically
1569 ** initialized when [sqlite3_open()] is called if it has not be initialized
1570 ** already.  ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
1571 ** compile-time option, then the automatic calls to sqlite3_initialize()
1572 ** are omitted and the application must call sqlite3_initialize() directly
1573 ** prior to using any other SQLite interface.  For maximum portability,
1574 ** it is recommended that applications always invoke sqlite3_initialize()
1575 ** directly prior to using any other SQLite interface.  Future releases
1576 ** of SQLite may require this.  In other words, the behavior exhibited
1577 ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
1578 ** default behavior in some future release of SQLite.
1579 **
1580 ** The sqlite3_os_init() routine does operating-system specific
1581 ** initialization of the SQLite library.  The sqlite3_os_end()
1582 ** routine undoes the effect of sqlite3_os_init().  Typical tasks
1583 ** performed by these routines include allocation or deallocation
1584 ** of static resources, initialization of global variables,
1585 ** setting up a default [sqlite3_vfs] module, or setting up
1586 ** a default configuration using [sqlite3_config()].
1587 **
1588 ** The application should never invoke either sqlite3_os_init()
1589 ** or sqlite3_os_end() directly.  The application should only invoke
1590 ** sqlite3_initialize() and sqlite3_shutdown().  The sqlite3_os_init()
1591 ** interface is called automatically by sqlite3_initialize() and
1592 ** sqlite3_os_end() is called by sqlite3_shutdown().  Appropriate
1593 ** implementations for sqlite3_os_init() and sqlite3_os_end()
1594 ** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
1595 ** When [custom builds | built for other platforms]
1596 ** (using the [SQLITE_OS_OTHER=1] compile-time
1597 ** option) the application must supply a suitable implementation for
1598 ** sqlite3_os_init() and sqlite3_os_end().  An application-supplied
1599 ** implementation of sqlite3_os_init() or sqlite3_os_end()
1600 ** must return [SQLITE_OK] on success and some other [error code] upon
1601 ** failure.
1602 */
1603 SQLITE_API int sqlite3_initialize(void);
1604 SQLITE_API int sqlite3_shutdown(void);
1605 SQLITE_API int sqlite3_os_init(void);
1606 SQLITE_API int sqlite3_os_end(void);
1607 
1608 /*
1609 ** CAPI3REF: Configuring The SQLite Library
1610 **
1611 ** The sqlite3_config() interface is used to make global configuration
1612 ** changes to SQLite in order to tune SQLite to the specific needs of
1613 ** the application.  The default configuration is recommended for most
1614 ** applications and so this routine is usually not necessary.  It is
1615 ** provided to support rare applications with unusual needs.
1616 **
1617 ** <b>The sqlite3_config() interface is not threadsafe. The application
1618 ** must ensure that no other SQLite interfaces are invoked by other
1619 ** threads while sqlite3_config() is running.</b>
1620 **
1621 ** The sqlite3_config() interface
1622 ** may only be invoked prior to library initialization using
1623 ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
1624 ** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
1625 ** [sqlite3_shutdown()] then it will return SQLITE_MISUSE.
1626 ** Note, however, that ^sqlite3_config() can be called as part of the
1627 ** implementation of an application-defined [sqlite3_os_init()].
1628 **
1629 ** The first argument to sqlite3_config() is an integer
1630 ** [configuration option] that determines
1631 ** what property of SQLite is to be configured.  Subsequent arguments
1632 ** vary depending on the [configuration option]
1633 ** in the first argument.
1634 **
1635 ** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
1636 ** ^If the option is unknown or SQLite is unable to set the option
1637 ** then this routine returns a non-zero [error code].
1638 */
1639 SQLITE_API int sqlite3_config(int, ...);
1640 
1641 /*
1642 ** CAPI3REF: Configure database connections
1643 ** METHOD: sqlite3
1644 **
1645 ** The sqlite3_db_config() interface is used to make configuration
1646 ** changes to a [database connection].  The interface is similar to
1647 ** [sqlite3_config()] except that the changes apply to a single
1648 ** [database connection] (specified in the first argument).
1649 **
1650 ** The second argument to sqlite3_db_config(D,V,...)  is the
1651 ** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code
1652 ** that indicates what aspect of the [database connection] is being configured.
1653 ** Subsequent arguments vary depending on the configuration verb.
1654 **
1655 ** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
1656 ** the call is considered successful.
1657 */
1658 SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...);
1659 
1660 /*
1661 ** CAPI3REF: Memory Allocation Routines
1662 **
1663 ** An instance of this object defines the interface between SQLite
1664 ** and low-level memory allocation routines.
1665 **
1666 ** This object is used in only one place in the SQLite interface.
1667 ** A pointer to an instance of this object is the argument to
1668 ** [sqlite3_config()] when the configuration option is
1669 ** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].
1670 ** By creating an instance of this object
1671 ** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
1672 ** during configuration, an application can specify an alternative
1673 ** memory allocation subsystem for SQLite to use for all of its
1674 ** dynamic memory needs.
1675 **
1676 ** Note that SQLite comes with several [built-in memory allocators]
1677 ** that are perfectly adequate for the overwhelming majority of applications
1678 ** and that this object is only useful to a tiny minority of applications
1679 ** with specialized memory allocation requirements.  This object is
1680 ** also used during testing of SQLite in order to specify an alternative
1681 ** memory allocator that simulates memory out-of-memory conditions in
1682 ** order to verify that SQLite recovers gracefully from such
1683 ** conditions.
1684 **
1685 ** The xMalloc, xRealloc, and xFree methods must work like the
1686 ** malloc(), realloc() and free() functions from the standard C library.
1687 ** ^SQLite guarantees that the second argument to
1688 ** xRealloc is always a value returned by a prior call to xRoundup.
1689 **
1690 ** xSize should return the allocated size of a memory allocation
1691 ** previously obtained from xMalloc or xRealloc.  The allocated size
1692 ** is always at least as big as the requested size but may be larger.
1693 **
1694 ** The xRoundup method returns what would be the allocated size of
1695 ** a memory allocation given a particular requested size.  Most memory
1696 ** allocators round up memory allocations at least to the next multiple
1697 ** of 8.  Some allocators round up to a larger multiple or to a power of 2.
1698 ** Every memory allocation request coming in through [sqlite3_malloc()]
1699 ** or [sqlite3_realloc()] first calls xRoundup.  If xRoundup returns 0,
1700 ** that causes the corresponding memory allocation to fail.
1701 **
1702 ** The xInit method initializes the memory allocator.  For example,
1703 ** it might allocate any required mutexes or initialize internal data
1704 ** structures.  The xShutdown method is invoked (indirectly) by
1705 ** [sqlite3_shutdown()] and should deallocate any resources acquired
1706 ** by xInit.  The pAppData pointer is used as the only parameter to
1707 ** xInit and xShutdown.
1708 **
1709 ** SQLite holds the [SQLITE_MUTEX_STATIC_MAIN] mutex when it invokes
1710 ** the xInit method, so the xInit method need not be threadsafe.  The
1711 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
1712 ** not need to be threadsafe either.  For all other methods, SQLite
1713 ** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
1714 ** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
1715 ** it is by default) and so the methods are automatically serialized.
1716 ** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
1717 ** methods must be threadsafe or else make their own arrangements for
1718 ** serialization.
1719 **
1720 ** SQLite will never invoke xInit() more than once without an intervening
1721 ** call to xShutdown().
1722 */
1723 typedef struct sqlite3_mem_methods sqlite3_mem_methods;
1724 struct sqlite3_mem_methods {
1725   void *(*xMalloc)(int);         /* Memory allocation function */
1726   void (*xFree)(void*);          /* Free a prior allocation */
1727   void *(*xRealloc)(void*,int);  /* Resize an allocation */
1728   int (*xSize)(void*);           /* Return the size of an allocation */
1729   int (*xRoundup)(int);          /* Round up request size to allocation size */
1730   int (*xInit)(void*);           /* Initialize the memory allocator */
1731   void (*xShutdown)(void*);      /* Deinitialize the memory allocator */
1732   void *pAppData;                /* Argument to xInit() and xShutdown() */
1733 };
1734 
1735 /*
1736 ** CAPI3REF: Configuration Options
1737 ** KEYWORDS: {configuration option}
1738 **
1739 ** These constants are the available integer configuration options that
1740 ** can be passed as the first argument to the [sqlite3_config()] interface.
1741 **
1742 ** New configuration options may be added in future releases of SQLite.
1743 ** Existing configuration options might be discontinued.  Applications
1744 ** should check the return code from [sqlite3_config()] to make sure that
1745 ** the call worked.  The [sqlite3_config()] interface will return a
1746 ** non-zero [error code] if a discontinued or unsupported configuration option
1747 ** is invoked.
1748 **
1749 ** <dl>
1750 ** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
1751 ** <dd>There are no arguments to this option.  ^This option sets the
1752 ** [threading mode] to Single-thread.  In other words, it disables
1753 ** all mutexing and puts SQLite into a mode where it can only be used
1754 ** by a single thread.   ^If SQLite is compiled with
1755 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1756 ** it is not possible to change the [threading mode] from its default
1757 ** value of Single-thread and so [sqlite3_config()] will return
1758 ** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
1759 ** configuration option.</dd>
1760 **
1761 ** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt>
1762 ** <dd>There are no arguments to this option.  ^This option sets the
1763 ** [threading mode] to Multi-thread.  In other words, it disables
1764 ** mutexing on [database connection] and [prepared statement] objects.
1765 ** The application is responsible for serializing access to
1766 ** [database connections] and [prepared statements].  But other mutexes
1767 ** are enabled so that SQLite will be safe to use in a multi-threaded
1768 ** environment as long as no two threads attempt to use the same
1769 ** [database connection] at the same time.  ^If SQLite is compiled with
1770 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1771 ** it is not possible to set the Multi-thread [threading mode] and
1772 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1773 ** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
1774 **
1775 ** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt>
1776 ** <dd>There are no arguments to this option.  ^This option sets the
1777 ** [threading mode] to Serialized. In other words, this option enables
1778 ** all mutexes including the recursive
1779 ** mutexes on [database connection] and [prepared statement] objects.
1780 ** In this mode (which is the default when SQLite is compiled with
1781 ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
1782 ** to [database connections] and [prepared statements] so that the
1783 ** application is free to use the same [database connection] or the
1784 ** same [prepared statement] in different threads at the same time.
1785 ** ^If SQLite is compiled with
1786 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1787 ** it is not possible to set the Serialized [threading mode] and
1788 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1789 ** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
1790 **
1791 ** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt>
1792 ** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is
1793 ** a pointer to an instance of the [sqlite3_mem_methods] structure.
1794 ** The argument specifies
1795 ** alternative low-level memory allocation routines to be used in place of
1796 ** the memory allocation routines built into SQLite.)^ ^SQLite makes
1797 ** its own private copy of the content of the [sqlite3_mem_methods] structure
1798 ** before the [sqlite3_config()] call returns.</dd>
1799 **
1800 ** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt>
1801 ** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which
1802 ** is a pointer to an instance of the [sqlite3_mem_methods] structure.
1803 ** The [sqlite3_mem_methods]
1804 ** structure is filled with the currently defined memory allocation routines.)^
1805 ** This option can be used to overload the default memory allocation
1806 ** routines with a wrapper that simulations memory allocation failure or
1807 ** tracks memory usage, for example. </dd>
1808 **
1809 ** [[SQLITE_CONFIG_SMALL_MALLOC]] <dt>SQLITE_CONFIG_SMALL_MALLOC</dt>
1810 ** <dd> ^The SQLITE_CONFIG_SMALL_MALLOC option takes single argument of
1811 ** type int, interpreted as a boolean, which if true provides a hint to
1812 ** SQLite that it should avoid large memory allocations if possible.
1813 ** SQLite will run faster if it is free to make large memory allocations,
1814 ** but some application might prefer to run slower in exchange for
1815 ** guarantees about memory fragmentation that are possible if large
1816 ** allocations are avoided.  This hint is normally off.
1817 ** </dd>
1818 **
1819 ** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt>
1820 ** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int,
1821 ** interpreted as a boolean, which enables or disables the collection of
1822 ** memory allocation statistics. ^(When memory allocation statistics are
1823 ** disabled, the following SQLite interfaces become non-operational:
1824 **   <ul>
1825 **   <li> [sqlite3_hard_heap_limit64()]
1826 **   <li> [sqlite3_memory_used()]
1827 **   <li> [sqlite3_memory_highwater()]
1828 **   <li> [sqlite3_soft_heap_limit64()]
1829 **   <li> [sqlite3_status64()]
1830 **   </ul>)^
1831 ** ^Memory allocation statistics are enabled by default unless SQLite is
1832 ** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
1833 ** allocation statistics are disabled by default.
1834 ** </dd>
1835 **
1836 ** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt>
1837 ** <dd> The SQLITE_CONFIG_SCRATCH option is no longer used.
1838 ** </dd>
1839 **
1840 ** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>
1841 ** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool
1842 ** that SQLite can use for the database page cache with the default page
1843 ** cache implementation.
1844 ** This configuration option is a no-op if an application-defined page
1845 ** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2].
1846 ** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to
1847 ** 8-byte aligned memory (pMem), the size of each page cache line (sz),
1848 ** and the number of cache lines (N).
1849 ** The sz argument should be the size of the largest database page
1850 ** (a power of two between 512 and 65536) plus some extra bytes for each
1851 ** page header.  ^The number of extra bytes needed by the page header
1852 ** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ].
1853 ** ^It is harmless, apart from the wasted memory,
1854 ** for the sz parameter to be larger than necessary.  The pMem
1855 ** argument must be either a NULL pointer or a pointer to an 8-byte
1856 ** aligned block of memory of at least sz*N bytes, otherwise
1857 ** subsequent behavior is undefined.
1858 ** ^When pMem is not NULL, SQLite will strive to use the memory provided
1859 ** to satisfy page cache needs, falling back to [sqlite3_malloc()] if
1860 ** a page cache line is larger than sz bytes or if all of the pMem buffer
1861 ** is exhausted.
1862 ** ^If pMem is NULL and N is non-zero, then each database connection
1863 ** does an initial bulk allocation for page cache memory
1864 ** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or
1865 ** of -1024*N bytes if N is negative, . ^If additional
1866 ** page cache memory is needed beyond what is provided by the initial
1867 ** allocation, then SQLite goes to [sqlite3_malloc()] separately for each
1868 ** additional cache line. </dd>
1869 **
1870 ** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt>
1871 ** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer
1872 ** that SQLite will use for all of its dynamic memory allocation needs
1873 ** beyond those provided for by [SQLITE_CONFIG_PAGECACHE].
1874 ** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled
1875 ** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns
1876 ** [SQLITE_ERROR] if invoked otherwise.
1877 ** ^There are three arguments to SQLITE_CONFIG_HEAP:
1878 ** An 8-byte aligned pointer to the memory,
1879 ** the number of bytes in the memory buffer, and the minimum allocation size.
1880 ** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
1881 ** to using its default memory allocator (the system malloc() implementation),
1882 ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC].  ^If the
1883 ** memory pointer is not NULL then the alternative memory
1884 ** allocator is engaged to handle all of SQLites memory allocation needs.
1885 ** The first pointer (the memory pointer) must be aligned to an 8-byte
1886 ** boundary or subsequent behavior of SQLite will be undefined.
1887 ** The minimum allocation size is capped at 2**12. Reasonable values
1888 ** for the minimum allocation size are 2**5 through 2**8.</dd>
1889 **
1890 ** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt>
1891 ** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a
1892 ** pointer to an instance of the [sqlite3_mutex_methods] structure.
1893 ** The argument specifies alternative low-level mutex routines to be used
1894 ** in place the mutex routines built into SQLite.)^  ^SQLite makes a copy of
1895 ** the content of the [sqlite3_mutex_methods] structure before the call to
1896 ** [sqlite3_config()] returns. ^If SQLite is compiled with
1897 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1898 ** the entire mutexing subsystem is omitted from the build and hence calls to
1899 ** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
1900 ** return [SQLITE_ERROR].</dd>
1901 **
1902 ** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt>
1903 ** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which
1904 ** is a pointer to an instance of the [sqlite3_mutex_methods] structure.  The
1905 ** [sqlite3_mutex_methods]
1906 ** structure is filled with the currently defined mutex routines.)^
1907 ** This option can be used to overload the default mutex allocation
1908 ** routines with a wrapper used to track mutex usage for performance
1909 ** profiling or testing, for example.   ^If SQLite is compiled with
1910 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1911 ** the entire mutexing subsystem is omitted from the build and hence calls to
1912 ** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
1913 ** return [SQLITE_ERROR].</dd>
1914 **
1915 ** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt>
1916 ** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine
1917 ** the default size of lookaside memory on each [database connection].
1918 ** The first argument is the
1919 ** size of each lookaside buffer slot and the second is the number of
1920 ** slots allocated to each database connection.)^  ^(SQLITE_CONFIG_LOOKASIDE
1921 ** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
1922 ** option to [sqlite3_db_config()] can be used to change the lookaside
1923 ** configuration on individual connections.)^ </dd>
1924 **
1925 ** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt>
1926 ** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is
1927 ** a pointer to an [sqlite3_pcache_methods2] object.  This object specifies
1928 ** the interface to a custom page cache implementation.)^
1929 ** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd>
1930 **
1931 ** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt>
1932 ** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which
1933 ** is a pointer to an [sqlite3_pcache_methods2] object.  SQLite copies of
1934 ** the current page cache implementation into that object.)^ </dd>
1935 **
1936 ** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>
1937 ** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite
1938 ** global [error log].
1939 ** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
1940 ** function with a call signature of void(*)(void*,int,const char*),
1941 ** and a pointer to void. ^If the function pointer is not NULL, it is
1942 ** invoked by [sqlite3_log()] to process each logging event.  ^If the
1943 ** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
1944 ** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
1945 ** passed through as the first parameter to the application-defined logger
1946 ** function whenever that function is invoked.  ^The second parameter to
1947 ** the logger function is a copy of the first parameter to the corresponding
1948 ** [sqlite3_log()] call and is intended to be a [result code] or an
1949 ** [extended result code].  ^The third parameter passed to the logger is
1950 ** log message after formatting via [sqlite3_snprintf()].
1951 ** The SQLite logging interface is not reentrant; the logger function
1952 ** supplied by the application must not invoke any SQLite interface.
1953 ** In a multi-threaded application, the application-defined logger
1954 ** function must be threadsafe. </dd>
1955 **
1956 ** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI
1957 ** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int.
1958 ** If non-zero, then URI handling is globally enabled. If the parameter is zero,
1959 ** then URI handling is globally disabled.)^ ^If URI handling is globally
1960 ** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()],
1961 ** [sqlite3_open16()] or
1962 ** specified as part of [ATTACH] commands are interpreted as URIs, regardless
1963 ** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
1964 ** connection is opened. ^If it is globally disabled, filenames are
1965 ** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
1966 ** database connection is opened. ^(By default, URI handling is globally
1967 ** disabled. The default value may be changed by compiling with the
1968 ** [SQLITE_USE_URI] symbol defined.)^
1969 **
1970 ** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN
1971 ** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer
1972 ** argument which is interpreted as a boolean in order to enable or disable
1973 ** the use of covering indices for full table scans in the query optimizer.
1974 ** ^The default setting is determined
1975 ** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on"
1976 ** if that compile-time option is omitted.
1977 ** The ability to disable the use of covering indices for full table scans
1978 ** is because some incorrectly coded legacy applications might malfunction
1979 ** when the optimization is enabled.  Providing the ability to
1980 ** disable the optimization allows the older, buggy application code to work
1981 ** without change even with newer versions of SQLite.
1982 **
1983 ** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]]
1984 ** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE
1985 ** <dd> These options are obsolete and should not be used by new code.
1986 ** They are retained for backwards compatibility but are now no-ops.
1987 ** </dd>
1988 **
1989 ** [[SQLITE_CONFIG_SQLLOG]]
1990 ** <dt>SQLITE_CONFIG_SQLLOG
1991 ** <dd>This option is only available if sqlite is compiled with the
1992 ** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should
1993 ** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int).
1994 ** The second should be of type (void*). The callback is invoked by the library
1995 ** in three separate circumstances, identified by the value passed as the
1996 ** fourth parameter. If the fourth parameter is 0, then the database connection
1997 ** passed as the second argument has just been opened. The third argument
1998 ** points to a buffer containing the name of the main database file. If the
1999 ** fourth parameter is 1, then the SQL statement that the third parameter
2000 ** points to has just been executed. Or, if the fourth parameter is 2, then
2001 ** the connection being passed as the second parameter is being closed. The
2002 ** third parameter is passed NULL In this case.  An example of using this
2003 ** configuration option can be seen in the "test_sqllog.c" source file in
2004 ** the canonical SQLite source tree.</dd>
2005 **
2006 ** [[SQLITE_CONFIG_MMAP_SIZE]]
2007 ** <dt>SQLITE_CONFIG_MMAP_SIZE
2008 ** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values
2009 ** that are the default mmap size limit (the default setting for
2010 ** [PRAGMA mmap_size]) and the maximum allowed mmap size limit.
2011 ** ^The default setting can be overridden by each database connection using
2012 ** either the [PRAGMA mmap_size] command, or by using the
2013 ** [SQLITE_FCNTL_MMAP_SIZE] file control.  ^(The maximum allowed mmap size
2014 ** will be silently truncated if necessary so that it does not exceed the
2015 ** compile-time maximum mmap size set by the
2016 ** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^
2017 ** ^If either argument to this option is negative, then that argument is
2018 ** changed to its compile-time default.
2019 **
2020 ** [[SQLITE_CONFIG_WIN32_HEAPSIZE]]
2021 ** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE
2022 ** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is
2023 ** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro
2024 ** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value
2025 ** that specifies the maximum size of the created heap.
2026 **
2027 ** [[SQLITE_CONFIG_PCACHE_HDRSZ]]
2028 ** <dt>SQLITE_CONFIG_PCACHE_HDRSZ
2029 ** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which
2030 ** is a pointer to an integer and writes into that integer the number of extra
2031 ** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE].
2032 ** The amount of extra space required can change depending on the compiler,
2033 ** target platform, and SQLite version.
2034 **
2035 ** [[SQLITE_CONFIG_PMASZ]]
2036 ** <dt>SQLITE_CONFIG_PMASZ
2037 ** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which
2038 ** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded
2039 ** sorter to that integer.  The default minimum PMA Size is set by the
2040 ** [SQLITE_SORTER_PMASZ] compile-time option.  New threads are launched
2041 ** to help with sort operations when multithreaded sorting
2042 ** is enabled (using the [PRAGMA threads] command) and the amount of content
2043 ** to be sorted exceeds the page size times the minimum of the
2044 ** [PRAGMA cache_size] setting and this value.
2045 **
2046 ** [[SQLITE_CONFIG_STMTJRNL_SPILL]]
2047 ** <dt>SQLITE_CONFIG_STMTJRNL_SPILL
2048 ** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which
2049 ** becomes the [statement journal] spill-to-disk threshold.
2050 ** [Statement journals] are held in memory until their size (in bytes)
2051 ** exceeds this threshold, at which point they are written to disk.
2052 ** Or if the threshold is -1, statement journals are always held
2053 ** exclusively in memory.
2054 ** Since many statement journals never become large, setting the spill
2055 ** threshold to a value such as 64KiB can greatly reduce the amount of
2056 ** I/O required to support statement rollback.
2057 ** The default value for this setting is controlled by the
2058 ** [SQLITE_STMTJRNL_SPILL] compile-time option.
2059 **
2060 ** [[SQLITE_CONFIG_SORTERREF_SIZE]]
2061 ** <dt>SQLITE_CONFIG_SORTERREF_SIZE
2062 ** <dd>The SQLITE_CONFIG_SORTERREF_SIZE option accepts a single parameter
2063 ** of type (int) - the new value of the sorter-reference size threshold.
2064 ** Usually, when SQLite uses an external sort to order records according
2065 ** to an ORDER BY clause, all fields required by the caller are present in the
2066 ** sorted records. However, if SQLite determines based on the declared type
2067 ** of a table column that its values are likely to be very large - larger
2068 ** than the configured sorter-reference size threshold - then a reference
2069 ** is stored in each sorted record and the required column values loaded
2070 ** from the database as records are returned in sorted order. The default
2071 ** value for this option is to never use this optimization. Specifying a
2072 ** negative value for this option restores the default behaviour.
2073 ** This option is only available if SQLite is compiled with the
2074 ** [SQLITE_ENABLE_SORTER_REFERENCES] compile-time option.
2075 **
2076 ** [[SQLITE_CONFIG_MEMDB_MAXSIZE]]
2077 ** <dt>SQLITE_CONFIG_MEMDB_MAXSIZE
2078 ** <dd>The SQLITE_CONFIG_MEMDB_MAXSIZE option accepts a single parameter
2079 ** [sqlite3_int64] parameter which is the default maximum size for an in-memory
2080 ** database created using [sqlite3_deserialize()].  This default maximum
2081 ** size can be adjusted up or down for individual databases using the
2082 ** [SQLITE_FCNTL_SIZE_LIMIT] [sqlite3_file_control|file-control].  If this
2083 ** configuration setting is never used, then the default maximum is determined
2084 ** by the [SQLITE_MEMDB_DEFAULT_MAXSIZE] compile-time option.  If that
2085 ** compile-time option is not set, then the default maximum is 1073741824.
2086 ** </dl>
2087 */
2088 #define SQLITE_CONFIG_SINGLETHREAD  1  /* nil */
2089 #define SQLITE_CONFIG_MULTITHREAD   2  /* nil */
2090 #define SQLITE_CONFIG_SERIALIZED    3  /* nil */
2091 #define SQLITE_CONFIG_MALLOC        4  /* sqlite3_mem_methods* */
2092 #define SQLITE_CONFIG_GETMALLOC     5  /* sqlite3_mem_methods* */
2093 #define SQLITE_CONFIG_SCRATCH       6  /* No longer used */
2094 #define SQLITE_CONFIG_PAGECACHE     7  /* void*, int sz, int N */
2095 #define SQLITE_CONFIG_HEAP          8  /* void*, int nByte, int min */
2096 #define SQLITE_CONFIG_MEMSTATUS     9  /* boolean */
2097 #define SQLITE_CONFIG_MUTEX        10  /* sqlite3_mutex_methods* */
2098 #define SQLITE_CONFIG_GETMUTEX     11  /* sqlite3_mutex_methods* */
2099 /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */
2100 #define SQLITE_CONFIG_LOOKASIDE    13  /* int int */
2101 #define SQLITE_CONFIG_PCACHE       14  /* no-op */
2102 #define SQLITE_CONFIG_GETPCACHE    15  /* no-op */
2103 #define SQLITE_CONFIG_LOG          16  /* xFunc, void* */
2104 #define SQLITE_CONFIG_URI          17  /* int */
2105 #define SQLITE_CONFIG_PCACHE2      18  /* sqlite3_pcache_methods2* */
2106 #define SQLITE_CONFIG_GETPCACHE2   19  /* sqlite3_pcache_methods2* */
2107 #define SQLITE_CONFIG_COVERING_INDEX_SCAN 20  /* int */
2108 #define SQLITE_CONFIG_SQLLOG       21  /* xSqllog, void* */
2109 #define SQLITE_CONFIG_MMAP_SIZE    22  /* sqlite3_int64, sqlite3_int64 */
2110 #define SQLITE_CONFIG_WIN32_HEAPSIZE      23  /* int nByte */
2111 #define SQLITE_CONFIG_PCACHE_HDRSZ        24  /* int *psz */
2112 #define SQLITE_CONFIG_PMASZ               25  /* unsigned int szPma */
2113 #define SQLITE_CONFIG_STMTJRNL_SPILL      26  /* int nByte */
2114 #define SQLITE_CONFIG_SMALL_MALLOC        27  /* boolean */
2115 #define SQLITE_CONFIG_SORTERREF_SIZE      28  /* int nByte */
2116 #define SQLITE_CONFIG_MEMDB_MAXSIZE       29  /* sqlite3_int64 */
2117 
2118 /*
2119 ** CAPI3REF: Database Connection Configuration Options
2120 **
2121 ** These constants are the available integer configuration options that
2122 ** can be passed as the second argument to the [sqlite3_db_config()] interface.
2123 **
2124 ** New configuration options may be added in future releases of SQLite.
2125 ** Existing configuration options might be discontinued.  Applications
2126 ** should check the return code from [sqlite3_db_config()] to make sure that
2127 ** the call worked.  ^The [sqlite3_db_config()] interface will return a
2128 ** non-zero [error code] if a discontinued or unsupported configuration option
2129 ** is invoked.
2130 **
2131 ** <dl>
2132 ** [[SQLITE_DBCONFIG_LOOKASIDE]]
2133 ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
2134 ** <dd> ^This option takes three additional arguments that determine the
2135 ** [lookaside memory allocator] configuration for the [database connection].
2136 ** ^The first argument (the third parameter to [sqlite3_db_config()] is a
2137 ** pointer to a memory buffer to use for lookaside memory.
2138 ** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
2139 ** may be NULL in which case SQLite will allocate the
2140 ** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
2141 ** size of each lookaside buffer slot.  ^The third argument is the number of
2142 ** slots.  The size of the buffer in the first argument must be greater than
2143 ** or equal to the product of the second and third arguments.  The buffer
2144 ** must be aligned to an 8-byte boundary.  ^If the second argument to
2145 ** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
2146 ** rounded down to the next smaller multiple of 8.  ^(The lookaside memory
2147 ** configuration for a database connection can only be changed when that
2148 ** connection is not currently using lookaside memory, or in other words
2149 ** when the "current value" returned by
2150 ** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero.
2151 ** Any attempt to change the lookaside memory configuration when lookaside
2152 ** memory is in use leaves the configuration unchanged and returns
2153 ** [SQLITE_BUSY].)^</dd>
2154 **
2155 ** [[SQLITE_DBCONFIG_ENABLE_FKEY]]
2156 ** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
2157 ** <dd> ^This option is used to enable or disable the enforcement of
2158 ** [foreign key constraints].  There should be two additional arguments.
2159 ** The first argument is an integer which is 0 to disable FK enforcement,
2160 ** positive to enable FK enforcement or negative to leave FK enforcement
2161 ** unchanged.  The second parameter is a pointer to an integer into which
2162 ** is written 0 or 1 to indicate whether FK enforcement is off or on
2163 ** following this call.  The second parameter may be a NULL pointer, in
2164 ** which case the FK enforcement setting is not reported back. </dd>
2165 **
2166 ** [[SQLITE_DBCONFIG_ENABLE_TRIGGER]]
2167 ** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
2168 ** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
2169 ** There should be two additional arguments.
2170 ** The first argument is an integer which is 0 to disable triggers,
2171 ** positive to enable triggers or negative to leave the setting unchanged.
2172 ** The second parameter is a pointer to an integer into which
2173 ** is written 0 or 1 to indicate whether triggers are disabled or enabled
2174 ** following this call.  The second parameter may be a NULL pointer, in
2175 ** which case the trigger setting is not reported back.
2176 **
2177 ** <p>Originally this option disabled all triggers.  ^(However, since
2178 ** SQLite version 3.35.0, TEMP triggers are still allowed even if
2179 ** this option is off.  So, in other words, this option now only disables
2180 ** triggers in the main database schema or in the schemas of ATTACH-ed
2181 ** databases.)^ </dd>
2182 **
2183 ** [[SQLITE_DBCONFIG_ENABLE_VIEW]]
2184 ** <dt>SQLITE_DBCONFIG_ENABLE_VIEW</dt>
2185 ** <dd> ^This option is used to enable or disable [CREATE VIEW | views].
2186 ** There should be two additional arguments.
2187 ** The first argument is an integer which is 0 to disable views,
2188 ** positive to enable views or negative to leave the setting unchanged.
2189 ** The second parameter is a pointer to an integer into which
2190 ** is written 0 or 1 to indicate whether views are disabled or enabled
2191 ** following this call.  The second parameter may be a NULL pointer, in
2192 ** which case the view setting is not reported back.
2193 **
2194 ** <p>Originally this option disabled all views.  ^(However, since
2195 ** SQLite version 3.35.0, TEMP views are still allowed even if
2196 ** this option is off.  So, in other words, this option now only disables
2197 ** views in the main database schema or in the schemas of ATTACH-ed
2198 ** databases.)^ </dd>
2199 **
2200 ** [[SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER]]
2201 ** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt>
2202 ** <dd> ^This option is used to enable or disable the
2203 ** [fts3_tokenizer()] function which is part of the
2204 ** [FTS3] full-text search engine extension.
2205 ** There should be two additional arguments.
2206 ** The first argument is an integer which is 0 to disable fts3_tokenizer() or
2207 ** positive to enable fts3_tokenizer() or negative to leave the setting
2208 ** unchanged.
2209 ** The second parameter is a pointer to an integer into which
2210 ** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled
2211 ** following this call.  The second parameter may be a NULL pointer, in
2212 ** which case the new setting is not reported back. </dd>
2213 **
2214 ** [[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION]]
2215 ** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt>
2216 ** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()]
2217 ** interface independently of the [load_extension()] SQL function.
2218 ** The [sqlite3_enable_load_extension()] API enables or disables both the
2219 ** C-API [sqlite3_load_extension()] and the SQL function [load_extension()].
2220 ** There should be two additional arguments.
2221 ** When the first argument to this interface is 1, then only the C-API is
2222 ** enabled and the SQL function remains disabled.  If the first argument to
2223 ** this interface is 0, then both the C-API and the SQL function are disabled.
2224 ** If the first argument is -1, then no changes are made to state of either the
2225 ** C-API or the SQL function.
2226 ** The second parameter is a pointer to an integer into which
2227 ** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface
2228 ** is disabled or enabled following this call.  The second parameter may
2229 ** be a NULL pointer, in which case the new setting is not reported back.
2230 ** </dd>
2231 **
2232 ** [[SQLITE_DBCONFIG_MAINDBNAME]] <dt>SQLITE_DBCONFIG_MAINDBNAME</dt>
2233 ** <dd> ^This option is used to change the name of the "main" database
2234 ** schema.  ^The sole argument is a pointer to a constant UTF8 string
2235 ** which will become the new schema name in place of "main".  ^SQLite
2236 ** does not make a copy of the new main schema name string, so the application
2237 ** must ensure that the argument passed into this DBCONFIG option is unchanged
2238 ** until after the database connection closes.
2239 ** </dd>
2240 **
2241 ** [[SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE]]
2242 ** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt>
2243 ** <dd> Usually, when a database in wal mode is closed or detached from a
2244 ** database handle, SQLite checks if this will mean that there are now no
2245 ** connections at all to the database. If so, it performs a checkpoint
2246 ** operation before closing the connection. This option may be used to
2247 ** override this behaviour. The first parameter passed to this operation
2248 ** is an integer - positive to disable checkpoints-on-close, or zero (the
2249 ** default) to enable them, and negative to leave the setting unchanged.
2250 ** The second parameter is a pointer to an integer
2251 ** into which is written 0 or 1 to indicate whether checkpoints-on-close
2252 ** have been disabled - 0 if they are not disabled, 1 if they are.
2253 ** </dd>
2254 **
2255 ** [[SQLITE_DBCONFIG_ENABLE_QPSG]] <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt>
2256 ** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates
2257 ** the [query planner stability guarantee] (QPSG).  When the QPSG is active,
2258 ** a single SQL query statement will always use the same algorithm regardless
2259 ** of values of [bound parameters].)^ The QPSG disables some query optimizations
2260 ** that look at the values of bound parameters, which can make some queries
2261 ** slower.  But the QPSG has the advantage of more predictable behavior.  With
2262 ** the QPSG active, SQLite will always use the same query plan in the field as
2263 ** was used during testing in the lab.
2264 ** The first argument to this setting is an integer which is 0 to disable
2265 ** the QPSG, positive to enable QPSG, or negative to leave the setting
2266 ** unchanged. The second parameter is a pointer to an integer into which
2267 ** is written 0 or 1 to indicate whether the QPSG is disabled or enabled
2268 ** following this call.
2269 ** </dd>
2270 **
2271 ** [[SQLITE_DBCONFIG_TRIGGER_EQP]] <dt>SQLITE_DBCONFIG_TRIGGER_EQP</dt>
2272 ** <dd> By default, the output of EXPLAIN QUERY PLAN commands does not
2273 ** include output for any operations performed by trigger programs. This
2274 ** option is used to set or clear (the default) a flag that governs this
2275 ** behavior. The first parameter passed to this operation is an integer -
2276 ** positive to enable output for trigger programs, or zero to disable it,
2277 ** or negative to leave the setting unchanged.
2278 ** The second parameter is a pointer to an integer into which is written
2279 ** 0 or 1 to indicate whether output-for-triggers has been disabled - 0 if
2280 ** it is not disabled, 1 if it is.
2281 ** </dd>
2282 **
2283 ** [[SQLITE_DBCONFIG_RESET_DATABASE]] <dt>SQLITE_DBCONFIG_RESET_DATABASE</dt>
2284 ** <dd> Set the SQLITE_DBCONFIG_RESET_DATABASE flag and then run
2285 ** [VACUUM] in order to reset a database back to an empty database
2286 ** with no schema and no content. The following process works even for
2287 ** a badly corrupted database file:
2288 ** <ol>
2289 ** <li> If the database connection is newly opened, make sure it has read the
2290 **      database schema by preparing then discarding some query against the
2291 **      database, or calling sqlite3_table_column_metadata(), ignoring any
2292 **      errors.  This step is only necessary if the application desires to keep
2293 **      the database in WAL mode after the reset if it was in WAL mode before
2294 **      the reset.
2295 ** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 1, 0);
2296 ** <li> [sqlite3_exec](db, "[VACUUM]", 0, 0, 0);
2297 ** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 0, 0);
2298 ** </ol>
2299 ** Because resetting a database is destructive and irreversible, the
2300 ** process requires the use of this obscure API and multiple steps to help
2301 ** ensure that it does not happen by accident.
2302 **
2303 ** [[SQLITE_DBCONFIG_DEFENSIVE]] <dt>SQLITE_DBCONFIG_DEFENSIVE</dt>
2304 ** <dd>The SQLITE_DBCONFIG_DEFENSIVE option activates or deactivates the
2305 ** "defensive" flag for a database connection.  When the defensive
2306 ** flag is enabled, language features that allow ordinary SQL to
2307 ** deliberately corrupt the database file are disabled.  The disabled
2308 ** features include but are not limited to the following:
2309 ** <ul>
2310 ** <li> The [PRAGMA writable_schema=ON] statement.
2311 ** <li> The [PRAGMA journal_mode=OFF] statement.
2312 ** <li> Writes to the [sqlite_dbpage] virtual table.
2313 ** <li> Direct writes to [shadow tables].
2314 ** </ul>
2315 ** </dd>
2316 **
2317 ** [[SQLITE_DBCONFIG_WRITABLE_SCHEMA]] <dt>SQLITE_DBCONFIG_WRITABLE_SCHEMA</dt>
2318 ** <dd>The SQLITE_DBCONFIG_WRITABLE_SCHEMA option activates or deactivates the
2319 ** "writable_schema" flag. This has the same effect and is logically equivalent
2320 ** to setting [PRAGMA writable_schema=ON] or [PRAGMA writable_schema=OFF].
2321 ** The first argument to this setting is an integer which is 0 to disable
2322 ** the writable_schema, positive to enable writable_schema, or negative to
2323 ** leave the setting unchanged. The second parameter is a pointer to an
2324 ** integer into which is written 0 or 1 to indicate whether the writable_schema
2325 ** is enabled or disabled following this call.
2326 ** </dd>
2327 **
2328 ** [[SQLITE_DBCONFIG_LEGACY_ALTER_TABLE]]
2329 ** <dt>SQLITE_DBCONFIG_LEGACY_ALTER_TABLE</dt>
2330 ** <dd>The SQLITE_DBCONFIG_LEGACY_ALTER_TABLE option activates or deactivates
2331 ** the legacy behavior of the [ALTER TABLE RENAME] command such it
2332 ** behaves as it did prior to [version 3.24.0] (2018-06-04).  See the
2333 ** "Compatibility Notice" on the [ALTER TABLE RENAME documentation] for
2334 ** additional information. This feature can also be turned on and off
2335 ** using the [PRAGMA legacy_alter_table] statement.
2336 ** </dd>
2337 **
2338 ** [[SQLITE_DBCONFIG_DQS_DML]]
2339 ** <dt>SQLITE_DBCONFIG_DQS_DML</td>
2340 ** <dd>The SQLITE_DBCONFIG_DQS_DML option activates or deactivates
2341 ** the legacy [double-quoted string literal] misfeature for DML statements
2342 ** only, that is DELETE, INSERT, SELECT, and UPDATE statements. The
2343 ** default value of this setting is determined by the [-DSQLITE_DQS]
2344 ** compile-time option.
2345 ** </dd>
2346 **
2347 ** [[SQLITE_DBCONFIG_DQS_DDL]]
2348 ** <dt>SQLITE_DBCONFIG_DQS_DDL</td>
2349 ** <dd>The SQLITE_DBCONFIG_DQS option activates or deactivates
2350 ** the legacy [double-quoted string literal] misfeature for DDL statements,
2351 ** such as CREATE TABLE and CREATE INDEX. The
2352 ** default value of this setting is determined by the [-DSQLITE_DQS]
2353 ** compile-time option.
2354 ** </dd>
2355 **
2356 ** [[SQLITE_DBCONFIG_TRUSTED_SCHEMA]]
2357 ** <dt>SQLITE_DBCONFIG_TRUSTED_SCHEMA</td>
2358 ** <dd>The SQLITE_DBCONFIG_TRUSTED_SCHEMA option tells SQLite to
2359 ** assume that database schemas are untainted by malicious content.
2360 ** When the SQLITE_DBCONFIG_TRUSTED_SCHEMA option is disabled, SQLite
2361 ** takes additional defensive steps to protect the application from harm
2362 ** including:
2363 ** <ul>
2364 ** <li> Prohibit the use of SQL functions inside triggers, views,
2365 ** CHECK constraints, DEFAULT clauses, expression indexes,
2366 ** partial indexes, or generated columns
2367 ** unless those functions are tagged with [SQLITE_INNOCUOUS].
2368 ** <li> Prohibit the use of virtual tables inside of triggers or views
2369 ** unless those virtual tables are tagged with [SQLITE_VTAB_INNOCUOUS].
2370 ** </ul>
2371 ** This setting defaults to "on" for legacy compatibility, however
2372 ** all applications are advised to turn it off if possible. This setting
2373 ** can also be controlled using the [PRAGMA trusted_schema] statement.
2374 ** </dd>
2375 **
2376 ** [[SQLITE_DBCONFIG_LEGACY_FILE_FORMAT]]
2377 ** <dt>SQLITE_DBCONFIG_LEGACY_FILE_FORMAT</td>
2378 ** <dd>The SQLITE_DBCONFIG_LEGACY_FILE_FORMAT option activates or deactivates
2379 ** the legacy file format flag.  When activated, this flag causes all newly
2380 ** created database file to have a schema format version number (the 4-byte
2381 ** integer found at offset 44 into the database header) of 1.  This in turn
2382 ** means that the resulting database file will be readable and writable by
2383 ** any SQLite version back to 3.0.0 ([dateof:3.0.0]).  Without this setting,
2384 ** newly created databases are generally not understandable by SQLite versions
2385 ** prior to 3.3.0 ([dateof:3.3.0]).  As these words are written, there
2386 ** is now scarcely any need to generated database files that are compatible
2387 ** all the way back to version 3.0.0, and so this setting is of little
2388 ** practical use, but is provided so that SQLite can continue to claim the
2389 ** ability to generate new database files that are compatible with  version
2390 ** 3.0.0.
2391 ** <p>Note that when the SQLITE_DBCONFIG_LEGACY_FILE_FORMAT setting is on,
2392 ** the [VACUUM] command will fail with an obscure error when attempting to
2393 ** process a table with generated columns and a descending index.  This is
2394 ** not considered a bug since SQLite versions 3.3.0 and earlier do not support
2395 ** either generated columns or decending indexes.
2396 ** </dd>
2397 ** </dl>
2398 */
2399 #define SQLITE_DBCONFIG_MAINDBNAME            1000 /* const char* */
2400 #define SQLITE_DBCONFIG_LOOKASIDE             1001 /* void* int int */
2401 #define SQLITE_DBCONFIG_ENABLE_FKEY           1002 /* int int* */
2402 #define SQLITE_DBCONFIG_ENABLE_TRIGGER        1003 /* int int* */
2403 #define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */
2404 #define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */
2405 #define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE      1006 /* int int* */
2406 #define SQLITE_DBCONFIG_ENABLE_QPSG           1007 /* int int* */
2407 #define SQLITE_DBCONFIG_TRIGGER_EQP           1008 /* int int* */
2408 #define SQLITE_DBCONFIG_RESET_DATABASE        1009 /* int int* */
2409 #define SQLITE_DBCONFIG_DEFENSIVE             1010 /* int int* */
2410 #define SQLITE_DBCONFIG_WRITABLE_SCHEMA       1011 /* int int* */
2411 #define SQLITE_DBCONFIG_LEGACY_ALTER_TABLE    1012 /* int int* */
2412 #define SQLITE_DBCONFIG_DQS_DML               1013 /* int int* */
2413 #define SQLITE_DBCONFIG_DQS_DDL               1014 /* int int* */
2414 #define SQLITE_DBCONFIG_ENABLE_VIEW           1015 /* int int* */
2415 #define SQLITE_DBCONFIG_LEGACY_FILE_FORMAT    1016 /* int int* */
2416 #define SQLITE_DBCONFIG_TRUSTED_SCHEMA        1017 /* int int* */
2417 #define SQLITE_DBCONFIG_MAX                   1017 /* Largest DBCONFIG */
2418 
2419 /*
2420 ** CAPI3REF: Enable Or Disable Extended Result Codes
2421 ** METHOD: sqlite3
2422 **
2423 ** ^The sqlite3_extended_result_codes() routine enables or disables the
2424 ** [extended result codes] feature of SQLite. ^The extended result
2425 ** codes are disabled by default for historical compatibility.
2426 */
2427 SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff);
2428 
2429 /*
2430 ** CAPI3REF: Last Insert Rowid
2431 ** METHOD: sqlite3
2432 **
2433 ** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables)
2434 ** has a unique 64-bit signed
2435 ** integer key called the [ROWID | "rowid"]. ^The rowid is always available
2436 ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
2437 ** names are not also used by explicitly declared columns. ^If
2438 ** the table has a column of type [INTEGER PRIMARY KEY] then that column
2439 ** is another alias for the rowid.
2440 **
2441 ** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of
2442 ** the most recent successful [INSERT] into a rowid table or [virtual table]
2443 ** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not
2444 ** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred
2445 ** on the database connection D, then sqlite3_last_insert_rowid(D) returns
2446 ** zero.
2447 **
2448 ** As well as being set automatically as rows are inserted into database
2449 ** tables, the value returned by this function may be set explicitly by
2450 ** [sqlite3_set_last_insert_rowid()]
2451 **
2452 ** Some virtual table implementations may INSERT rows into rowid tables as
2453 ** part of committing a transaction (e.g. to flush data accumulated in memory
2454 ** to disk). In this case subsequent calls to this function return the rowid
2455 ** associated with these internal INSERT operations, which leads to
2456 ** unintuitive results. Virtual table implementations that do write to rowid
2457 ** tables in this way can avoid this problem by restoring the original
2458 ** rowid value using [sqlite3_set_last_insert_rowid()] before returning
2459 ** control to the user.
2460 **
2461 ** ^(If an [INSERT] occurs within a trigger then this routine will
2462 ** return the [rowid] of the inserted row as long as the trigger is
2463 ** running. Once the trigger program ends, the value returned
2464 ** by this routine reverts to what it was before the trigger was fired.)^
2465 **
2466 ** ^An [INSERT] that fails due to a constraint violation is not a
2467 ** successful [INSERT] and does not change the value returned by this
2468 ** routine.  ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
2469 ** and INSERT OR ABORT make no changes to the return value of this
2470 ** routine when their insertion fails.  ^(When INSERT OR REPLACE
2471 ** encounters a constraint violation, it does not fail.  The
2472 ** INSERT continues to completion after deleting rows that caused
2473 ** the constraint problem so INSERT OR REPLACE will always change
2474 ** the return value of this interface.)^
2475 **
2476 ** ^For the purposes of this routine, an [INSERT] is considered to
2477 ** be successful even if it is subsequently rolled back.
2478 **
2479 ** This function is accessible to SQL statements via the
2480 ** [last_insert_rowid() SQL function].
2481 **
2482 ** If a separate thread performs a new [INSERT] on the same
2483 ** database connection while the [sqlite3_last_insert_rowid()]
2484 ** function is running and thus changes the last insert [rowid],
2485 ** then the value returned by [sqlite3_last_insert_rowid()] is
2486 ** unpredictable and might not equal either the old or the new
2487 ** last insert [rowid].
2488 */
2489 SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
2490 
2491 /*
2492 ** CAPI3REF: Set the Last Insert Rowid value.
2493 ** METHOD: sqlite3
2494 **
2495 ** The sqlite3_set_last_insert_rowid(D, R) method allows the application to
2496 ** set the value returned by calling sqlite3_last_insert_rowid(D) to R
2497 ** without inserting a row into the database.
2498 */
2499 SQLITE_API void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64);
2500 
2501 /*
2502 ** CAPI3REF: Count The Number Of Rows Modified
2503 ** METHOD: sqlite3
2504 **
2505 ** ^These functions return the number of rows modified, inserted or
2506 ** deleted by the most recently completed INSERT, UPDATE or DELETE
2507 ** statement on the database connection specified by the only parameter.
2508 ** The two functions are identical except for the type of the return value
2509 ** and that if the number of rows modified by the most recent INSERT, UPDATE
2510 ** or DELETE is greater than the maximum value supported by type "int", then
2511 ** the return value of sqlite3_changes() is undefined. ^Executing any other
2512 ** type of SQL statement does not modify the value returned by these functions.
2513 **
2514 ** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are
2515 ** considered - auxiliary changes caused by [CREATE TRIGGER | triggers],
2516 ** [foreign key actions] or [REPLACE] constraint resolution are not counted.
2517 **
2518 ** Changes to a view that are intercepted by
2519 ** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value
2520 ** returned by sqlite3_changes() immediately after an INSERT, UPDATE or
2521 ** DELETE statement run on a view is always zero. Only changes made to real
2522 ** tables are counted.
2523 **
2524 ** Things are more complicated if the sqlite3_changes() function is
2525 ** executed while a trigger program is running. This may happen if the
2526 ** program uses the [changes() SQL function], or if some other callback
2527 ** function invokes sqlite3_changes() directly. Essentially:
2528 **
2529 ** <ul>
2530 **   <li> ^(Before entering a trigger program the value returned by
2531 **        sqlite3_changes() function is saved. After the trigger program
2532 **        has finished, the original value is restored.)^
2533 **
2534 **   <li> ^(Within a trigger program each INSERT, UPDATE and DELETE
2535 **        statement sets the value returned by sqlite3_changes()
2536 **        upon completion as normal. Of course, this value will not include
2537 **        any changes performed by sub-triggers, as the sqlite3_changes()
2538 **        value will be saved and restored after each sub-trigger has run.)^
2539 ** </ul>
2540 **
2541 ** ^This means that if the changes() SQL function (or similar) is used
2542 ** by the first INSERT, UPDATE or DELETE statement within a trigger, it
2543 ** returns the value as set when the calling statement began executing.
2544 ** ^If it is used by the second or subsequent such statement within a trigger
2545 ** program, the value returned reflects the number of rows modified by the
2546 ** previous INSERT, UPDATE or DELETE statement within the same trigger.
2547 **
2548 ** If a separate thread makes changes on the same database connection
2549 ** while [sqlite3_changes()] is running then the value returned
2550 ** is unpredictable and not meaningful.
2551 **
2552 ** See also:
2553 ** <ul>
2554 ** <li> the [sqlite3_total_changes()] interface
2555 ** <li> the [count_changes pragma]
2556 ** <li> the [changes() SQL function]
2557 ** <li> the [data_version pragma]
2558 ** </ul>
2559 */
2560 SQLITE_API int sqlite3_changes(sqlite3*);
2561 SQLITE_API sqlite3_int64 sqlite3_changes64(sqlite3*);
2562 
2563 /*
2564 ** CAPI3REF: Total Number Of Rows Modified
2565 ** METHOD: sqlite3
2566 **
2567 ** ^These functions return the total number of rows inserted, modified or
2568 ** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed
2569 ** since the database connection was opened, including those executed as
2570 ** part of trigger programs. The two functions are identical except for the
2571 ** type of the return value and that if the number of rows modified by the
2572 ** connection exceeds the maximum value supported by type "int", then
2573 ** the return value of sqlite3_total_changes() is undefined. ^Executing
2574 ** any other type of SQL statement does not affect the value returned by
2575 ** sqlite3_total_changes().
2576 **
2577 ** ^Changes made as part of [foreign key actions] are included in the
2578 ** count, but those made as part of REPLACE constraint resolution are
2579 ** not. ^Changes to a view that are intercepted by INSTEAD OF triggers
2580 ** are not counted.
2581 **
2582 ** The [sqlite3_total_changes(D)] interface only reports the number
2583 ** of rows that changed due to SQL statement run against database
2584 ** connection D.  Any changes by other database connections are ignored.
2585 ** To detect changes against a database file from other database
2586 ** connections use the [PRAGMA data_version] command or the
2587 ** [SQLITE_FCNTL_DATA_VERSION] [file control].
2588 **
2589 ** If a separate thread makes changes on the same database connection
2590 ** while [sqlite3_total_changes()] is running then the value
2591 ** returned is unpredictable and not meaningful.
2592 **
2593 ** See also:
2594 ** <ul>
2595 ** <li> the [sqlite3_changes()] interface
2596 ** <li> the [count_changes pragma]
2597 ** <li> the [changes() SQL function]
2598 ** <li> the [data_version pragma]
2599 ** <li> the [SQLITE_FCNTL_DATA_VERSION] [file control]
2600 ** </ul>
2601 */
2602 SQLITE_API int sqlite3_total_changes(sqlite3*);
2603 SQLITE_API sqlite3_int64 sqlite3_total_changes64(sqlite3*);
2604 
2605 /*
2606 ** CAPI3REF: Interrupt A Long-Running Query
2607 ** METHOD: sqlite3
2608 **
2609 ** ^This function causes any pending database operation to abort and
2610 ** return at its earliest opportunity. This routine is typically
2611 ** called in response to a user action such as pressing "Cancel"
2612 ** or Ctrl-C where the user wants a long query operation to halt
2613 ** immediately.
2614 **
2615 ** ^It is safe to call this routine from a thread different from the
2616 ** thread that is currently running the database operation.  But it
2617 ** is not safe to call this routine with a [database connection] that
2618 ** is closed or might close before sqlite3_interrupt() returns.
2619 **
2620 ** ^If an SQL operation is very nearly finished at the time when
2621 ** sqlite3_interrupt() is called, then it might not have an opportunity
2622 ** to be interrupted and might continue to completion.
2623 **
2624 ** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
2625 ** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
2626 ** that is inside an explicit transaction, then the entire transaction
2627 ** will be rolled back automatically.
2628 **
2629 ** ^The sqlite3_interrupt(D) call is in effect until all currently running
2630 ** SQL statements on [database connection] D complete.  ^Any new SQL statements
2631 ** that are started after the sqlite3_interrupt() call and before the
2632 ** running statement count reaches zero are interrupted as if they had been
2633 ** running prior to the sqlite3_interrupt() call.  ^New SQL statements
2634 ** that are started after the running statement count reaches zero are
2635 ** not effected by the sqlite3_interrupt().
2636 ** ^A call to sqlite3_interrupt(D) that occurs when there are no running
2637 ** SQL statements is a no-op and has no effect on SQL statements
2638 ** that are started after the sqlite3_interrupt() call returns.
2639 */
2640 SQLITE_API void sqlite3_interrupt(sqlite3*);
2641 
2642 /*
2643 ** CAPI3REF: Determine If An SQL Statement Is Complete
2644 **
2645 ** These routines are useful during command-line input to determine if the
2646 ** currently entered text seems to form a complete SQL statement or
2647 ** if additional input is needed before sending the text into
2648 ** SQLite for parsing.  ^These routines return 1 if the input string
2649 ** appears to be a complete SQL statement.  ^A statement is judged to be
2650 ** complete if it ends with a semicolon token and is not a prefix of a
2651 ** well-formed CREATE TRIGGER statement.  ^Semicolons that are embedded within
2652 ** string literals or quoted identifier names or comments are not
2653 ** independent tokens (they are part of the token in which they are
2654 ** embedded) and thus do not count as a statement terminator.  ^Whitespace
2655 ** and comments that follow the final semicolon are ignored.
2656 **
2657 ** ^These routines return 0 if the statement is incomplete.  ^If a
2658 ** memory allocation fails, then SQLITE_NOMEM is returned.
2659 **
2660 ** ^These routines do not parse the SQL statements thus
2661 ** will not detect syntactically incorrect SQL.
2662 **
2663 ** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior
2664 ** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
2665 ** automatically by sqlite3_complete16().  If that initialization fails,
2666 ** then the return value from sqlite3_complete16() will be non-zero
2667 ** regardless of whether or not the input SQL is complete.)^
2668 **
2669 ** The input to [sqlite3_complete()] must be a zero-terminated
2670 ** UTF-8 string.
2671 **
2672 ** The input to [sqlite3_complete16()] must be a zero-terminated
2673 ** UTF-16 string in native byte order.
2674 */
2675 SQLITE_API int sqlite3_complete(const char *sql);
2676 SQLITE_API int sqlite3_complete16(const void *sql);
2677 
2678 /*
2679 ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
2680 ** KEYWORDS: {busy-handler callback} {busy handler}
2681 ** METHOD: sqlite3
2682 **
2683 ** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X
2684 ** that might be invoked with argument P whenever
2685 ** an attempt is made to access a database table associated with
2686 ** [database connection] D when another thread
2687 ** or process has the table locked.
2688 ** The sqlite3_busy_handler() interface is used to implement
2689 ** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout].
2690 **
2691 ** ^If the busy callback is NULL, then [SQLITE_BUSY]
2692 ** is returned immediately upon encountering the lock.  ^If the busy callback
2693 ** is not NULL, then the callback might be invoked with two arguments.
2694 **
2695 ** ^The first argument to the busy handler is a copy of the void* pointer which
2696 ** is the third argument to sqlite3_busy_handler().  ^The second argument to
2697 ** the busy handler callback is the number of times that the busy handler has
2698 ** been invoked previously for the same locking event.  ^If the
2699 ** busy callback returns 0, then no additional attempts are made to
2700 ** access the database and [SQLITE_BUSY] is returned
2701 ** to the application.
2702 ** ^If the callback returns non-zero, then another attempt
2703 ** is made to access the database and the cycle repeats.
2704 **
2705 ** The presence of a busy handler does not guarantee that it will be invoked
2706 ** when there is lock contention. ^If SQLite determines that invoking the busy
2707 ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
2708 ** to the application instead of invoking the
2709 ** busy handler.
2710 ** Consider a scenario where one process is holding a read lock that
2711 ** it is trying to promote to a reserved lock and
2712 ** a second process is holding a reserved lock that it is trying
2713 ** to promote to an exclusive lock.  The first process cannot proceed
2714 ** because it is blocked by the second and the second process cannot
2715 ** proceed because it is blocked by the first.  If both processes
2716 ** invoke the busy handlers, neither will make any progress.  Therefore,
2717 ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
2718 ** will induce the first process to release its read lock and allow
2719 ** the second process to proceed.
2720 **
2721 ** ^The default busy callback is NULL.
2722 **
2723 ** ^(There can only be a single busy handler defined for each
2724 ** [database connection].  Setting a new busy handler clears any
2725 ** previously set handler.)^  ^Note that calling [sqlite3_busy_timeout()]
2726 ** or evaluating [PRAGMA busy_timeout=N] will change the
2727 ** busy handler and thus clear any previously set busy handler.
2728 **
2729 ** The busy callback should not take any actions which modify the
2730 ** database connection that invoked the busy handler.  In other words,
2731 ** the busy handler is not reentrant.  Any such actions
2732 ** result in undefined behavior.
2733 **
2734 ** A busy handler must not close the database connection
2735 ** or [prepared statement] that invoked the busy handler.
2736 */
2737 SQLITE_API int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*);
2738 
2739 /*
2740 ** CAPI3REF: Set A Busy Timeout
2741 ** METHOD: sqlite3
2742 **
2743 ** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
2744 ** for a specified amount of time when a table is locked.  ^The handler
2745 ** will sleep multiple times until at least "ms" milliseconds of sleeping
2746 ** have accumulated.  ^After at least "ms" milliseconds of sleeping,
2747 ** the handler returns 0 which causes [sqlite3_step()] to return
2748 ** [SQLITE_BUSY].
2749 **
2750 ** ^Calling this routine with an argument less than or equal to zero
2751 ** turns off all busy handlers.
2752 **
2753 ** ^(There can only be a single busy handler for a particular
2754 ** [database connection] at any given moment.  If another busy handler
2755 ** was defined  (using [sqlite3_busy_handler()]) prior to calling
2756 ** this routine, that other busy handler is cleared.)^
2757 **
2758 ** See also:  [PRAGMA busy_timeout]
2759 */
2760 SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms);
2761 
2762 /*
2763 ** CAPI3REF: Convenience Routines For Running Queries
2764 ** METHOD: sqlite3
2765 **
2766 ** This is a legacy interface that is preserved for backwards compatibility.
2767 ** Use of this interface is not recommended.
2768 **
2769 ** Definition: A <b>result table</b> is memory data structure created by the
2770 ** [sqlite3_get_table()] interface.  A result table records the
2771 ** complete query results from one or more queries.
2772 **
2773 ** The table conceptually has a number of rows and columns.  But
2774 ** these numbers are not part of the result table itself.  These
2775 ** numbers are obtained separately.  Let N be the number of rows
2776 ** and M be the number of columns.
2777 **
2778 ** A result table is an array of pointers to zero-terminated UTF-8 strings.
2779 ** There are (N+1)*M elements in the array.  The first M pointers point
2780 ** to zero-terminated strings that  contain the names of the columns.
2781 ** The remaining entries all point to query results.  NULL values result
2782 ** in NULL pointers.  All other values are in their UTF-8 zero-terminated
2783 ** string representation as returned by [sqlite3_column_text()].
2784 **
2785 ** A result table might consist of one or more memory allocations.
2786 ** It is not safe to pass a result table directly to [sqlite3_free()].
2787 ** A result table should be deallocated using [sqlite3_free_table()].
2788 **
2789 ** ^(As an example of the result table format, suppose a query result
2790 ** is as follows:
2791 **
2792 ** <blockquote><pre>
2793 **        Name        | Age
2794 **        -----------------------
2795 **        Alice       | 43
2796 **        Bob         | 28
2797 **        Cindy       | 21
2798 ** </pre></blockquote>
2799 **
2800 ** There are two columns (M==2) and three rows (N==3).  Thus the
2801 ** result table has 8 entries.  Suppose the result table is stored
2802 ** in an array named azResult.  Then azResult holds this content:
2803 **
2804 ** <blockquote><pre>
2805 **        azResult&#91;0] = "Name";
2806 **        azResult&#91;1] = "Age";
2807 **        azResult&#91;2] = "Alice";
2808 **        azResult&#91;3] = "43";
2809 **        azResult&#91;4] = "Bob";
2810 **        azResult&#91;5] = "28";
2811 **        azResult&#91;6] = "Cindy";
2812 **        azResult&#91;7] = "21";
2813 ** </pre></blockquote>)^
2814 **
2815 ** ^The sqlite3_get_table() function evaluates one or more
2816 ** semicolon-separated SQL statements in the zero-terminated UTF-8
2817 ** string of its 2nd parameter and returns a result table to the
2818 ** pointer given in its 3rd parameter.
2819 **
2820 ** After the application has finished with the result from sqlite3_get_table(),
2821 ** it must pass the result table pointer to sqlite3_free_table() in order to
2822 ** release the memory that was malloced.  Because of the way the
2823 ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
2824 ** function must not try to call [sqlite3_free()] directly.  Only
2825 ** [sqlite3_free_table()] is able to release the memory properly and safely.
2826 **
2827 ** The sqlite3_get_table() interface is implemented as a wrapper around
2828 ** [sqlite3_exec()].  The sqlite3_get_table() routine does not have access
2829 ** to any internal data structures of SQLite.  It uses only the public
2830 ** interface defined here.  As a consequence, errors that occur in the
2831 ** wrapper layer outside of the internal [sqlite3_exec()] call are not
2832 ** reflected in subsequent calls to [sqlite3_errcode()] or
2833 ** [sqlite3_errmsg()].
2834 */
2835 SQLITE_API int sqlite3_get_table(
2836   sqlite3 *db,          /* An open database */
2837   const char *zSql,     /* SQL to be evaluated */
2838   char ***pazResult,    /* Results of the query */
2839   int *pnRow,           /* Number of result rows written here */
2840   int *pnColumn,        /* Number of result columns written here */
2841   char **pzErrmsg       /* Error msg written here */
2842 );
2843 SQLITE_API void sqlite3_free_table(char **result);
2844 
2845 /*
2846 ** CAPI3REF: Formatted String Printing Functions
2847 **
2848 ** These routines are work-alikes of the "printf()" family of functions
2849 ** from the standard C library.
2850 ** These routines understand most of the common formatting options from
2851 ** the standard library printf()
2852 ** plus some additional non-standard formats ([%q], [%Q], [%w], and [%z]).
2853 ** See the [built-in printf()] documentation for details.
2854 **
2855 ** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
2856 ** results into memory obtained from [sqlite3_malloc64()].
2857 ** The strings returned by these two routines should be
2858 ** released by [sqlite3_free()].  ^Both routines return a
2859 ** NULL pointer if [sqlite3_malloc64()] is unable to allocate enough
2860 ** memory to hold the resulting string.
2861 **
2862 ** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
2863 ** the standard C library.  The result is written into the
2864 ** buffer supplied as the second parameter whose size is given by
2865 ** the first parameter. Note that the order of the
2866 ** first two parameters is reversed from snprintf().)^  This is an
2867 ** historical accident that cannot be fixed without breaking
2868 ** backwards compatibility.  ^(Note also that sqlite3_snprintf()
2869 ** returns a pointer to its buffer instead of the number of
2870 ** characters actually written into the buffer.)^  We admit that
2871 ** the number of characters written would be a more useful return
2872 ** value but we cannot change the implementation of sqlite3_snprintf()
2873 ** now without breaking compatibility.
2874 **
2875 ** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
2876 ** guarantees that the buffer is always zero-terminated.  ^The first
2877 ** parameter "n" is the total size of the buffer, including space for
2878 ** the zero terminator.  So the longest string that can be completely
2879 ** written will be n-1 characters.
2880 **
2881 ** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
2882 **
2883 ** See also:  [built-in printf()], [printf() SQL function]
2884 */
2885 SQLITE_API char *sqlite3_mprintf(const char*,...);
2886 SQLITE_API char *sqlite3_vmprintf(const char*, va_list);
2887 SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...);
2888 SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list);
2889 
2890 /*
2891 ** CAPI3REF: Memory Allocation Subsystem
2892 **
2893 ** The SQLite core uses these three routines for all of its own
2894 ** internal memory allocation needs. "Core" in the previous sentence
2895 ** does not include operating-system specific [VFS] implementation.  The
2896 ** Windows VFS uses native malloc() and free() for some operations.
2897 **
2898 ** ^The sqlite3_malloc() routine returns a pointer to a block
2899 ** of memory at least N bytes in length, where N is the parameter.
2900 ** ^If sqlite3_malloc() is unable to obtain sufficient free
2901 ** memory, it returns a NULL pointer.  ^If the parameter N to
2902 ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
2903 ** a NULL pointer.
2904 **
2905 ** ^The sqlite3_malloc64(N) routine works just like
2906 ** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead
2907 ** of a signed 32-bit integer.
2908 **
2909 ** ^Calling sqlite3_free() with a pointer previously returned
2910 ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
2911 ** that it might be reused.  ^The sqlite3_free() routine is
2912 ** a no-op if is called with a NULL pointer.  Passing a NULL pointer
2913 ** to sqlite3_free() is harmless.  After being freed, memory
2914 ** should neither be read nor written.  Even reading previously freed
2915 ** memory might result in a segmentation fault or other severe error.
2916 ** Memory corruption, a segmentation fault, or other severe error
2917 ** might result if sqlite3_free() is called with a non-NULL pointer that
2918 ** was not obtained from sqlite3_malloc() or sqlite3_realloc().
2919 **
2920 ** ^The sqlite3_realloc(X,N) interface attempts to resize a
2921 ** prior memory allocation X to be at least N bytes.
2922 ** ^If the X parameter to sqlite3_realloc(X,N)
2923 ** is a NULL pointer then its behavior is identical to calling
2924 ** sqlite3_malloc(N).
2925 ** ^If the N parameter to sqlite3_realloc(X,N) is zero or
2926 ** negative then the behavior is exactly the same as calling
2927 ** sqlite3_free(X).
2928 ** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation
2929 ** of at least N bytes in size or NULL if insufficient memory is available.
2930 ** ^If M is the size of the prior allocation, then min(N,M) bytes
2931 ** of the prior allocation are copied into the beginning of buffer returned
2932 ** by sqlite3_realloc(X,N) and the prior allocation is freed.
2933 ** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the
2934 ** prior allocation is not freed.
2935 **
2936 ** ^The sqlite3_realloc64(X,N) interfaces works the same as
2937 ** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead
2938 ** of a 32-bit signed integer.
2939 **
2940 ** ^If X is a memory allocation previously obtained from sqlite3_malloc(),
2941 ** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then
2942 ** sqlite3_msize(X) returns the size of that memory allocation in bytes.
2943 ** ^The value returned by sqlite3_msize(X) might be larger than the number
2944 ** of bytes requested when X was allocated.  ^If X is a NULL pointer then
2945 ** sqlite3_msize(X) returns zero.  If X points to something that is not
2946 ** the beginning of memory allocation, or if it points to a formerly
2947 ** valid memory allocation that has now been freed, then the behavior
2948 ** of sqlite3_msize(X) is undefined and possibly harmful.
2949 **
2950 ** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(),
2951 ** sqlite3_malloc64(), and sqlite3_realloc64()
2952 ** is always aligned to at least an 8 byte boundary, or to a
2953 ** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
2954 ** option is used.
2955 **
2956 ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
2957 ** must be either NULL or else pointers obtained from a prior
2958 ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
2959 ** not yet been released.
2960 **
2961 ** The application must not read or write any part of
2962 ** a block of memory after it has been released using
2963 ** [sqlite3_free()] or [sqlite3_realloc()].
2964 */
2965 SQLITE_API void *sqlite3_malloc(int);
2966 SQLITE_API void *sqlite3_malloc64(sqlite3_uint64);
2967 SQLITE_API void *sqlite3_realloc(void*, int);
2968 SQLITE_API void *sqlite3_realloc64(void*, sqlite3_uint64);
2969 SQLITE_API void sqlite3_free(void*);
2970 SQLITE_API sqlite3_uint64 sqlite3_msize(void*);
2971 
2972 /*
2973 ** CAPI3REF: Memory Allocator Statistics
2974 **
2975 ** SQLite provides these two interfaces for reporting on the status
2976 ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
2977 ** routines, which form the built-in memory allocation subsystem.
2978 **
2979 ** ^The [sqlite3_memory_used()] routine returns the number of bytes
2980 ** of memory currently outstanding (malloced but not freed).
2981 ** ^The [sqlite3_memory_highwater()] routine returns the maximum
2982 ** value of [sqlite3_memory_used()] since the high-water mark
2983 ** was last reset.  ^The values returned by [sqlite3_memory_used()] and
2984 ** [sqlite3_memory_highwater()] include any overhead
2985 ** added by SQLite in its implementation of [sqlite3_malloc()],
2986 ** but not overhead added by the any underlying system library
2987 ** routines that [sqlite3_malloc()] may call.
2988 **
2989 ** ^The memory high-water mark is reset to the current value of
2990 ** [sqlite3_memory_used()] if and only if the parameter to
2991 ** [sqlite3_memory_highwater()] is true.  ^The value returned
2992 ** by [sqlite3_memory_highwater(1)] is the high-water mark
2993 ** prior to the reset.
2994 */
2995 SQLITE_API sqlite3_int64 sqlite3_memory_used(void);
2996 SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
2997 
2998 /*
2999 ** CAPI3REF: Pseudo-Random Number Generator
3000 **
3001 ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
3002 ** select random [ROWID | ROWIDs] when inserting new records into a table that
3003 ** already uses the largest possible [ROWID].  The PRNG is also used for
3004 ** the built-in random() and randomblob() SQL functions.  This interface allows
3005 ** applications to access the same PRNG for other purposes.
3006 **
3007 ** ^A call to this routine stores N bytes of randomness into buffer P.
3008 ** ^The P parameter can be a NULL pointer.
3009 **
3010 ** ^If this routine has not been previously called or if the previous
3011 ** call had N less than one or a NULL pointer for P, then the PRNG is
3012 ** seeded using randomness obtained from the xRandomness method of
3013 ** the default [sqlite3_vfs] object.
3014 ** ^If the previous call to this routine had an N of 1 or more and a
3015 ** non-NULL P then the pseudo-randomness is generated
3016 ** internally and without recourse to the [sqlite3_vfs] xRandomness
3017 ** method.
3018 */
3019 SQLITE_API void sqlite3_randomness(int N, void *P);
3020 
3021 /*
3022 ** CAPI3REF: Compile-Time Authorization Callbacks
3023 ** METHOD: sqlite3
3024 ** KEYWORDS: {authorizer callback}
3025 **
3026 ** ^This routine registers an authorizer callback with a particular
3027 ** [database connection], supplied in the first argument.
3028 ** ^The authorizer callback is invoked as SQL statements are being compiled
3029 ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
3030 ** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()],
3031 ** and [sqlite3_prepare16_v3()].  ^At various
3032 ** points during the compilation process, as logic is being created
3033 ** to perform various actions, the authorizer callback is invoked to
3034 ** see if those actions are allowed.  ^The authorizer callback should
3035 ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
3036 ** specific action but allow the SQL statement to continue to be
3037 ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
3038 ** rejected with an error.  ^If the authorizer callback returns
3039 ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
3040 ** then the [sqlite3_prepare_v2()] or equivalent call that triggered
3041 ** the authorizer will fail with an error message.
3042 **
3043 ** When the callback returns [SQLITE_OK], that means the operation
3044 ** requested is ok.  ^When the callback returns [SQLITE_DENY], the
3045 ** [sqlite3_prepare_v2()] or equivalent call that triggered the
3046 ** authorizer will fail with an error message explaining that
3047 ** access is denied.
3048 **
3049 ** ^The first parameter to the authorizer callback is a copy of the third
3050 ** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
3051 ** to the callback is an integer [SQLITE_COPY | action code] that specifies
3052 ** the particular action to be authorized. ^The third through sixth parameters
3053 ** to the callback are either NULL pointers or zero-terminated strings
3054 ** that contain additional details about the action to be authorized.
3055 ** Applications must always be prepared to encounter a NULL pointer in any
3056 ** of the third through the sixth parameters of the authorization callback.
3057 **
3058 ** ^If the action code is [SQLITE_READ]
3059 ** and the callback returns [SQLITE_IGNORE] then the
3060 ** [prepared statement] statement is constructed to substitute
3061 ** a NULL value in place of the table column that would have
3062 ** been read if [SQLITE_OK] had been returned.  The [SQLITE_IGNORE]
3063 ** return can be used to deny an untrusted user access to individual
3064 ** columns of a table.
3065 ** ^When a table is referenced by a [SELECT] but no column values are
3066 ** extracted from that table (for example in a query like
3067 ** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback
3068 ** is invoked once for that table with a column name that is an empty string.
3069 ** ^If the action code is [SQLITE_DELETE] and the callback returns
3070 ** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
3071 ** [truncate optimization] is disabled and all rows are deleted individually.
3072 **
3073 ** An authorizer is used when [sqlite3_prepare | preparing]
3074 ** SQL statements from an untrusted source, to ensure that the SQL statements
3075 ** do not try to access data they are not allowed to see, or that they do not
3076 ** try to execute malicious statements that damage the database.  For
3077 ** example, an application may allow a user to enter arbitrary
3078 ** SQL queries for evaluation by a database.  But the application does
3079 ** not want the user to be able to make arbitrary changes to the
3080 ** database.  An authorizer could then be put in place while the
3081 ** user-entered SQL is being [sqlite3_prepare | prepared] that
3082 ** disallows everything except [SELECT] statements.
3083 **
3084 ** Applications that need to process SQL from untrusted sources
3085 ** might also consider lowering resource limits using [sqlite3_limit()]
3086 ** and limiting database size using the [max_page_count] [PRAGMA]
3087 ** in addition to using an authorizer.
3088 **
3089 ** ^(Only a single authorizer can be in place on a database connection
3090 ** at a time.  Each call to sqlite3_set_authorizer overrides the
3091 ** previous call.)^  ^Disable the authorizer by installing a NULL callback.
3092 ** The authorizer is disabled by default.
3093 **
3094 ** The authorizer callback must not do anything that will modify
3095 ** the database connection that invoked the authorizer callback.
3096 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
3097 ** database connections for the meaning of "modify" in this paragraph.
3098 **
3099 ** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
3100 ** statement might be re-prepared during [sqlite3_step()] due to a
3101 ** schema change.  Hence, the application should ensure that the
3102 ** correct authorizer callback remains in place during the [sqlite3_step()].
3103 **
3104 ** ^Note that the authorizer callback is invoked only during
3105 ** [sqlite3_prepare()] or its variants.  Authorization is not
3106 ** performed during statement evaluation in [sqlite3_step()], unless
3107 ** as stated in the previous paragraph, sqlite3_step() invokes
3108 ** sqlite3_prepare_v2() to reprepare a statement after a schema change.
3109 */
3110 SQLITE_API int sqlite3_set_authorizer(
3111   sqlite3*,
3112   int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
3113   void *pUserData
3114 );
3115 
3116 /*
3117 ** CAPI3REF: Authorizer Return Codes
3118 **
3119 ** The [sqlite3_set_authorizer | authorizer callback function] must
3120 ** return either [SQLITE_OK] or one of these two constants in order
3121 ** to signal SQLite whether or not the action is permitted.  See the
3122 ** [sqlite3_set_authorizer | authorizer documentation] for additional
3123 ** information.
3124 **
3125 ** Note that SQLITE_IGNORE is also used as a [conflict resolution mode]
3126 ** returned from the [sqlite3_vtab_on_conflict()] interface.
3127 */
3128 #define SQLITE_DENY   1   /* Abort the SQL statement with an error */
3129 #define SQLITE_IGNORE 2   /* Don't allow access, but don't generate an error */
3130 
3131 /*
3132 ** CAPI3REF: Authorizer Action Codes
3133 **
3134 ** The [sqlite3_set_authorizer()] interface registers a callback function
3135 ** that is invoked to authorize certain SQL statement actions.  The
3136 ** second parameter to the callback is an integer code that specifies
3137 ** what action is being authorized.  These are the integer action codes that
3138 ** the authorizer callback may be passed.
3139 **
3140 ** These action code values signify what kind of operation is to be
3141 ** authorized.  The 3rd and 4th parameters to the authorization
3142 ** callback function will be parameters or NULL depending on which of these
3143 ** codes is used as the second parameter.  ^(The 5th parameter to the
3144 ** authorizer callback is the name of the database ("main", "temp",
3145 ** etc.) if applicable.)^  ^The 6th parameter to the authorizer callback
3146 ** is the name of the inner-most trigger or view that is responsible for
3147 ** the access attempt or NULL if this access attempt is directly from
3148 ** top-level SQL code.
3149 */
3150 /******************************************* 3rd ************ 4th ***********/
3151 #define SQLITE_CREATE_INDEX          1   /* Index Name      Table Name      */
3152 #define SQLITE_CREATE_TABLE          2   /* Table Name      NULL            */
3153 #define SQLITE_CREATE_TEMP_INDEX     3   /* Index Name      Table Name      */
3154 #define SQLITE_CREATE_TEMP_TABLE     4   /* Table Name      NULL            */
3155 #define SQLITE_CREATE_TEMP_TRIGGER   5   /* Trigger Name    Table Name      */
3156 #define SQLITE_CREATE_TEMP_VIEW      6   /* View Name       NULL            */
3157 #define SQLITE_CREATE_TRIGGER        7   /* Trigger Name    Table Name      */
3158 #define SQLITE_CREATE_VIEW           8   /* View Name       NULL            */
3159 #define SQLITE_DELETE                9   /* Table Name      NULL            */
3160 #define SQLITE_DROP_INDEX           10   /* Index Name      Table Name      */
3161 #define SQLITE_DROP_TABLE           11   /* Table Name      NULL            */
3162 #define SQLITE_DROP_TEMP_INDEX      12   /* Index Name      Table Name      */
3163 #define SQLITE_DROP_TEMP_TABLE      13   /* Table Name      NULL            */
3164 #define SQLITE_DROP_TEMP_TRIGGER    14   /* Trigger Name    Table Name      */
3165 #define SQLITE_DROP_TEMP_VIEW       15   /* View Name       NULL            */
3166 #define SQLITE_DROP_TRIGGER         16   /* Trigger Name    Table Name      */
3167 #define SQLITE_DROP_VIEW            17   /* View Name       NULL            */
3168 #define SQLITE_INSERT               18   /* Table Name      NULL            */
3169 #define SQLITE_PRAGMA               19   /* Pragma Name     1st arg or NULL */
3170 #define SQLITE_READ                 20   /* Table Name      Column Name     */
3171 #define SQLITE_SELECT               21   /* NULL            NULL            */
3172 #define SQLITE_TRANSACTION          22   /* Operation       NULL            */
3173 #define SQLITE_UPDATE               23   /* Table Name      Column Name     */
3174 #define SQLITE_ATTACH               24   /* Filename        NULL            */
3175 #define SQLITE_DETACH               25   /* Database Name   NULL            */
3176 #define SQLITE_ALTER_TABLE          26   /* Database Name   Table Name      */
3177 #define SQLITE_REINDEX              27   /* Index Name      NULL            */
3178 #define SQLITE_ANALYZE              28   /* Table Name      NULL            */
3179 #define SQLITE_CREATE_VTABLE        29   /* Table Name      Module Name     */
3180 #define SQLITE_DROP_VTABLE          30   /* Table Name      Module Name     */
3181 #define SQLITE_FUNCTION             31   /* NULL            Function Name   */
3182 #define SQLITE_SAVEPOINT            32   /* Operation       Savepoint Name  */
3183 #define SQLITE_COPY                  0   /* No longer used */
3184 #define SQLITE_RECURSIVE            33   /* NULL            NULL            */
3185 
3186 /*
3187 ** CAPI3REF: Tracing And Profiling Functions
3188 ** METHOD: sqlite3
3189 **
3190 ** These routines are deprecated. Use the [sqlite3_trace_v2()] interface
3191 ** instead of the routines described here.
3192 **
3193 ** These routines register callback functions that can be used for
3194 ** tracing and profiling the execution of SQL statements.
3195 **
3196 ** ^The callback function registered by sqlite3_trace() is invoked at
3197 ** various times when an SQL statement is being run by [sqlite3_step()].
3198 ** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
3199 ** SQL statement text as the statement first begins executing.
3200 ** ^(Additional sqlite3_trace() callbacks might occur
3201 ** as each triggered subprogram is entered.  The callbacks for triggers
3202 ** contain a UTF-8 SQL comment that identifies the trigger.)^
3203 **
3204 ** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit
3205 ** the length of [bound parameter] expansion in the output of sqlite3_trace().
3206 **
3207 ** ^The callback function registered by sqlite3_profile() is invoked
3208 ** as each SQL statement finishes.  ^The profile callback contains
3209 ** the original statement text and an estimate of wall-clock time
3210 ** of how long that statement took to run.  ^The profile callback
3211 ** time is in units of nanoseconds, however the current implementation
3212 ** is only capable of millisecond resolution so the six least significant
3213 ** digits in the time are meaningless.  Future versions of SQLite
3214 ** might provide greater resolution on the profiler callback.  Invoking
3215 ** either [sqlite3_trace()] or [sqlite3_trace_v2()] will cancel the
3216 ** profile callback.
3217 */
3218 SQLITE_API SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*,
3219    void(*xTrace)(void*,const char*), void*);
3220 SQLITE_API SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*,
3221    void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
3222 
3223 /*
3224 ** CAPI3REF: SQL Trace Event Codes
3225 ** KEYWORDS: SQLITE_TRACE
3226 **
3227 ** These constants identify classes of events that can be monitored
3228 ** using the [sqlite3_trace_v2()] tracing logic.  The M argument
3229 ** to [sqlite3_trace_v2(D,M,X,P)] is an OR-ed combination of one or more of
3230 ** the following constants.  ^The first argument to the trace callback
3231 ** is one of the following constants.
3232 **
3233 ** New tracing constants may be added in future releases.
3234 **
3235 ** ^A trace callback has four arguments: xCallback(T,C,P,X).
3236 ** ^The T argument is one of the integer type codes above.
3237 ** ^The C argument is a copy of the context pointer passed in as the
3238 ** fourth argument to [sqlite3_trace_v2()].
3239 ** The P and X arguments are pointers whose meanings depend on T.
3240 **
3241 ** <dl>
3242 ** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt>
3243 ** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement
3244 ** first begins running and possibly at other times during the
3245 ** execution of the prepared statement, such as at the start of each
3246 ** trigger subprogram. ^The P argument is a pointer to the
3247 ** [prepared statement]. ^The X argument is a pointer to a string which
3248 ** is the unexpanded SQL text of the prepared statement or an SQL comment
3249 ** that indicates the invocation of a trigger.  ^The callback can compute
3250 ** the same text that would have been returned by the legacy [sqlite3_trace()]
3251 ** interface by using the X argument when X begins with "--" and invoking
3252 ** [sqlite3_expanded_sql(P)] otherwise.
3253 **
3254 ** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt>
3255 ** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same
3256 ** information as is provided by the [sqlite3_profile()] callback.
3257 ** ^The P argument is a pointer to the [prepared statement] and the
3258 ** X argument points to a 64-bit integer which is the estimated of
3259 ** the number of nanosecond that the prepared statement took to run.
3260 ** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes.
3261 **
3262 ** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt>
3263 ** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared
3264 ** statement generates a single row of result.
3265 ** ^The P argument is a pointer to the [prepared statement] and the
3266 ** X argument is unused.
3267 **
3268 ** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt>
3269 ** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database
3270 ** connection closes.
3271 ** ^The P argument is a pointer to the [database connection] object
3272 ** and the X argument is unused.
3273 ** </dl>
3274 */
3275 #define SQLITE_TRACE_STMT       0x01
3276 #define SQLITE_TRACE_PROFILE    0x02
3277 #define SQLITE_TRACE_ROW        0x04
3278 #define SQLITE_TRACE_CLOSE      0x08
3279 
3280 /*
3281 ** CAPI3REF: SQL Trace Hook
3282 ** METHOD: sqlite3
3283 **
3284 ** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback
3285 ** function X against [database connection] D, using property mask M
3286 ** and context pointer P.  ^If the X callback is
3287 ** NULL or if the M mask is zero, then tracing is disabled.  The
3288 ** M argument should be the bitwise OR-ed combination of
3289 ** zero or more [SQLITE_TRACE] constants.
3290 **
3291 ** ^Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides
3292 ** (cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2().
3293 **
3294 ** ^The X callback is invoked whenever any of the events identified by
3295 ** mask M occur.  ^The integer return value from the callback is currently
3296 ** ignored, though this may change in future releases.  Callback
3297 ** implementations should return zero to ensure future compatibility.
3298 **
3299 ** ^A trace callback is invoked with four arguments: callback(T,C,P,X).
3300 ** ^The T argument is one of the [SQLITE_TRACE]
3301 ** constants to indicate why the callback was invoked.
3302 ** ^The C argument is a copy of the context pointer.
3303 ** The P and X arguments are pointers whose meanings depend on T.
3304 **
3305 ** The sqlite3_trace_v2() interface is intended to replace the legacy
3306 ** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which
3307 ** are deprecated.
3308 */
3309 SQLITE_API int sqlite3_trace_v2(
3310   sqlite3*,
3311   unsigned uMask,
3312   int(*xCallback)(unsigned,void*,void*,void*),
3313   void *pCtx
3314 );
3315 
3316 /*
3317 ** CAPI3REF: Query Progress Callbacks
3318 ** METHOD: sqlite3
3319 **
3320 ** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
3321 ** function X to be invoked periodically during long running calls to
3322 ** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for
3323 ** database connection D.  An example use for this
3324 ** interface is to keep a GUI updated during a large query.
3325 **
3326 ** ^The parameter P is passed through as the only parameter to the
3327 ** callback function X.  ^The parameter N is the approximate number of
3328 ** [virtual machine instructions] that are evaluated between successive
3329 ** invocations of the callback X.  ^If N is less than one then the progress
3330 ** handler is disabled.
3331 **
3332 ** ^Only a single progress handler may be defined at one time per
3333 ** [database connection]; setting a new progress handler cancels the
3334 ** old one.  ^Setting parameter X to NULL disables the progress handler.
3335 ** ^The progress handler is also disabled by setting N to a value less
3336 ** than 1.
3337 **
3338 ** ^If the progress callback returns non-zero, the operation is
3339 ** interrupted.  This feature can be used to implement a
3340 ** "Cancel" button on a GUI progress dialog box.
3341 **
3342 ** The progress handler callback must not do anything that will modify
3343 ** the database connection that invoked the progress handler.
3344 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
3345 ** database connections for the meaning of "modify" in this paragraph.
3346 **
3347 */
3348 SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
3349 
3350 /*
3351 ** CAPI3REF: Opening A New Database Connection
3352 ** CONSTRUCTOR: sqlite3
3353 **
3354 ** ^These routines open an SQLite database file as specified by the
3355 ** filename argument. ^The filename argument is interpreted as UTF-8 for
3356 ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
3357 ** order for sqlite3_open16(). ^(A [database connection] handle is usually
3358 ** returned in *ppDb, even if an error occurs.  The only exception is that
3359 ** if SQLite is unable to allocate memory to hold the [sqlite3] object,
3360 ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
3361 ** object.)^ ^(If the database is opened (and/or created) successfully, then
3362 ** [SQLITE_OK] is returned.  Otherwise an [error code] is returned.)^ ^The
3363 ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
3364 ** an English language description of the error following a failure of any
3365 ** of the sqlite3_open() routines.
3366 **
3367 ** ^The default encoding will be UTF-8 for databases created using
3368 ** sqlite3_open() or sqlite3_open_v2().  ^The default encoding for databases
3369 ** created using sqlite3_open16() will be UTF-16 in the native byte order.
3370 **
3371 ** Whether or not an error occurs when it is opened, resources
3372 ** associated with the [database connection] handle should be released by
3373 ** passing it to [sqlite3_close()] when it is no longer required.
3374 **
3375 ** The sqlite3_open_v2() interface works like sqlite3_open()
3376 ** except that it accepts two additional parameters for additional control
3377 ** over the new database connection.  ^(The flags parameter to
3378 ** sqlite3_open_v2() must include, at a minimum, one of the following
3379 ** three flag combinations:)^
3380 **
3381 ** <dl>
3382 ** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
3383 ** <dd>The database is opened in read-only mode.  If the database does not
3384 ** already exist, an error is returned.</dd>)^
3385 **
3386 ** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
3387 ** <dd>The database is opened for reading and writing if possible, or reading
3388 ** only if the file is write protected by the operating system.  In either
3389 ** case the database must already exist, otherwise an error is returned.</dd>)^
3390 **
3391 ** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
3392 ** <dd>The database is opened for reading and writing, and is created if
3393 ** it does not already exist. This is the behavior that is always used for
3394 ** sqlite3_open() and sqlite3_open16().</dd>)^
3395 ** </dl>
3396 **
3397 ** In addition to the required flags, the following optional flags are
3398 ** also supported:
3399 **
3400 ** <dl>
3401 ** ^(<dt>[SQLITE_OPEN_URI]</dt>
3402 ** <dd>The filename can be interpreted as a URI if this flag is set.</dd>)^
3403 **
3404 ** ^(<dt>[SQLITE_OPEN_MEMORY]</dt>
3405 ** <dd>The database will be opened as an in-memory database.  The database
3406 ** is named by the "filename" argument for the purposes of cache-sharing,
3407 ** if shared cache mode is enabled, but the "filename" is otherwise ignored.
3408 ** </dd>)^
3409 **
3410 ** ^(<dt>[SQLITE_OPEN_NOMUTEX]</dt>
3411 ** <dd>The new database connection will use the "multi-thread"
3412 ** [threading mode].)^  This means that separate threads are allowed
3413 ** to use SQLite at the same time, as long as each thread is using
3414 ** a different [database connection].
3415 **
3416 ** ^(<dt>[SQLITE_OPEN_FULLMUTEX]</dt>
3417 ** <dd>The new database connection will use the "serialized"
3418 ** [threading mode].)^  This means the multiple threads can safely
3419 ** attempt to use the same database connection at the same time.
3420 ** (Mutexes will block any actual concurrency, but in this mode
3421 ** there is no harm in trying.)
3422 **
3423 ** ^(<dt>[SQLITE_OPEN_SHAREDCACHE]</dt>
3424 ** <dd>The database is opened [shared cache] enabled, overriding
3425 ** the default shared cache setting provided by
3426 ** [sqlite3_enable_shared_cache()].)^
3427 **
3428 ** ^(<dt>[SQLITE_OPEN_PRIVATECACHE]</dt>
3429 ** <dd>The database is opened [shared cache] disabled, overriding
3430 ** the default shared cache setting provided by
3431 ** [sqlite3_enable_shared_cache()].)^
3432 **
3433 ** [[OPEN_EXRESCODE]] ^(<dt>[SQLITE_OPEN_EXRESCODE]</dt>
3434 ** <dd>The database connection comes up in "extended result code mode".
3435 ** In other words, the database behaves has if
3436 ** [sqlite3_extended_result_codes(db,1)] where called on the database
3437 ** connection as soon as the connection is created. In addition to setting
3438 ** the extended result code mode, this flag also causes [sqlite3_open_v2()]
3439 ** to return an extended result code.</dd>
3440 **
3441 ** [[OPEN_NOFOLLOW]] ^(<dt>[SQLITE_OPEN_NOFOLLOW]</dt>
3442 ** <dd>The database filename is not allowed to be a symbolic link</dd>
3443 ** </dl>)^
3444 **
3445 ** If the 3rd parameter to sqlite3_open_v2() is not one of the
3446 ** required combinations shown above optionally combined with other
3447 ** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits]
3448 ** then the behavior is undefined.  Historic versions of SQLite
3449 ** have silently ignored surplus bits in the flags parameter to
3450 ** sqlite3_open_v2(), however that behavior might not be carried through
3451 ** into future versions of SQLite and so applications should not rely
3452 ** upon it.  Note in particular that the SQLITE_OPEN_EXCLUSIVE flag is a no-op
3453 ** for sqlite3_open_v2().  The SQLITE_OPEN_EXCLUSIVE does *not* cause
3454 ** the open to fail if the database already exists.  The SQLITE_OPEN_EXCLUSIVE
3455 ** flag is intended for use by the [sqlite3_vfs|VFS interface] only, and not
3456 ** by sqlite3_open_v2().
3457 **
3458 ** ^The fourth parameter to sqlite3_open_v2() is the name of the
3459 ** [sqlite3_vfs] object that defines the operating system interface that
3460 ** the new database connection should use.  ^If the fourth parameter is
3461 ** a NULL pointer then the default [sqlite3_vfs] object is used.
3462 **
3463 ** ^If the filename is ":memory:", then a private, temporary in-memory database
3464 ** is created for the connection.  ^This in-memory database will vanish when
3465 ** the database connection is closed.  Future versions of SQLite might
3466 ** make use of additional special filenames that begin with the ":" character.
3467 ** It is recommended that when a database filename actually does begin with
3468 ** a ":" character you should prefix the filename with a pathname such as
3469 ** "./" to avoid ambiguity.
3470 **
3471 ** ^If the filename is an empty string, then a private, temporary
3472 ** on-disk database will be created.  ^This private database will be
3473 ** automatically deleted as soon as the database connection is closed.
3474 **
3475 ** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
3476 **
3477 ** ^If [URI filename] interpretation is enabled, and the filename argument
3478 ** begins with "file:", then the filename is interpreted as a URI. ^URI
3479 ** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
3480 ** set in the third argument to sqlite3_open_v2(), or if it has
3481 ** been enabled globally using the [SQLITE_CONFIG_URI] option with the
3482 ** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
3483 ** URI filename interpretation is turned off
3484 ** by default, but future releases of SQLite might enable URI filename
3485 ** interpretation by default.  See "[URI filenames]" for additional
3486 ** information.
3487 **
3488 ** URI filenames are parsed according to RFC 3986. ^If the URI contains an
3489 ** authority, then it must be either an empty string or the string
3490 ** "localhost". ^If the authority is not an empty string or "localhost", an
3491 ** error is returned to the caller. ^The fragment component of a URI, if
3492 ** present, is ignored.
3493 **
3494 ** ^SQLite uses the path component of the URI as the name of the disk file
3495 ** which contains the database. ^If the path begins with a '/' character,
3496 ** then it is interpreted as an absolute path. ^If the path does not begin
3497 ** with a '/' (meaning that the authority section is omitted from the URI)
3498 ** then the path is interpreted as a relative path.
3499 ** ^(On windows, the first component of an absolute path
3500 ** is a drive specification (e.g. "C:").)^
3501 **
3502 ** [[core URI query parameters]]
3503 ** The query component of a URI may contain parameters that are interpreted
3504 ** either by SQLite itself, or by a [VFS | custom VFS implementation].
3505 ** SQLite and its built-in [VFSes] interpret the
3506 ** following query parameters:
3507 **
3508 ** <ul>
3509 **   <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
3510 **     a VFS object that provides the operating system interface that should
3511 **     be used to access the database file on disk. ^If this option is set to
3512 **     an empty string the default VFS object is used. ^Specifying an unknown
3513 **     VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
3514 **     present, then the VFS specified by the option takes precedence over
3515 **     the value passed as the fourth parameter to sqlite3_open_v2().
3516 **
3517 **   <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw",
3518 **     "rwc", or "memory". Attempting to set it to any other value is
3519 **     an error)^.
3520 **     ^If "ro" is specified, then the database is opened for read-only
3521 **     access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the
3522 **     third argument to sqlite3_open_v2(). ^If the mode option is set to
3523 **     "rw", then the database is opened for read-write (but not create)
3524 **     access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had
3525 **     been set. ^Value "rwc" is equivalent to setting both
3526 **     SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE.  ^If the mode option is
3527 **     set to "memory" then a pure [in-memory database] that never reads
3528 **     or writes from disk is used. ^It is an error to specify a value for
3529 **     the mode parameter that is less restrictive than that specified by
3530 **     the flags passed in the third parameter to sqlite3_open_v2().
3531 **
3532 **   <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
3533 **     "private". ^Setting it to "shared" is equivalent to setting the
3534 **     SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
3535 **     sqlite3_open_v2(). ^Setting the cache parameter to "private" is
3536 **     equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
3537 **     ^If sqlite3_open_v2() is used and the "cache" parameter is present in
3538 **     a URI filename, its value overrides any behavior requested by setting
3539 **     SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.
3540 **
3541 **  <li> <b>psow</b>: ^The psow parameter indicates whether or not the
3542 **     [powersafe overwrite] property does or does not apply to the
3543 **     storage media on which the database file resides.
3544 **
3545 **  <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter
3546 **     which if set disables file locking in rollback journal modes.  This
3547 **     is useful for accessing a database on a filesystem that does not
3548 **     support locking.  Caution:  Database corruption might result if two
3549 **     or more processes write to the same database and any one of those
3550 **     processes uses nolock=1.
3551 **
3552 **  <li> <b>immutable</b>: ^The immutable parameter is a boolean query
3553 **     parameter that indicates that the database file is stored on
3554 **     read-only media.  ^When immutable is set, SQLite assumes that the
3555 **     database file cannot be changed, even by a process with higher
3556 **     privilege, and so the database is opened read-only and all locking
3557 **     and change detection is disabled.  Caution: Setting the immutable
3558 **     property on a database file that does in fact change can result
3559 **     in incorrect query results and/or [SQLITE_CORRUPT] errors.
3560 **     See also: [SQLITE_IOCAP_IMMUTABLE].
3561 **
3562 ** </ul>
3563 **
3564 ** ^Specifying an unknown parameter in the query component of a URI is not an
3565 ** error.  Future versions of SQLite might understand additional query
3566 ** parameters.  See "[query parameters with special meaning to SQLite]" for
3567 ** additional information.
3568 **
3569 ** [[URI filename examples]] <h3>URI filename examples</h3>
3570 **
3571 ** <table border="1" align=center cellpadding=5>
3572 ** <tr><th> URI filenames <th> Results
3573 ** <tr><td> file:data.db <td>
3574 **          Open the file "data.db" in the current directory.
3575 ** <tr><td> file:/home/fred/data.db<br>
3576 **          file:///home/fred/data.db <br>
3577 **          file://localhost/home/fred/data.db <br> <td>
3578 **          Open the database file "/home/fred/data.db".
3579 ** <tr><td> file://darkstar/home/fred/data.db <td>
3580 **          An error. "darkstar" is not a recognized authority.
3581 ** <tr><td style="white-space:nowrap">
3582 **          file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
3583 **     <td> Windows only: Open the file "data.db" on fred's desktop on drive
3584 **          C:. Note that the %20 escaping in this example is not strictly
3585 **          necessary - space characters can be used literally
3586 **          in URI filenames.
3587 ** <tr><td> file:data.db?mode=ro&cache=private <td>
3588 **          Open file "data.db" in the current directory for read-only access.
3589 **          Regardless of whether or not shared-cache mode is enabled by
3590 **          default, use a private cache.
3591 ** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td>
3592 **          Open file "/home/fred/data.db". Use the special VFS "unix-dotfile"
3593 **          that uses dot-files in place of posix advisory locking.
3594 ** <tr><td> file:data.db?mode=readonly <td>
3595 **          An error. "readonly" is not a valid option for the "mode" parameter.
3596 **          Use "ro" instead:  "file:data.db?mode=ro".
3597 ** </table>
3598 **
3599 ** ^URI hexadecimal escape sequences (%HH) are supported within the path and
3600 ** query components of a URI. A hexadecimal escape sequence consists of a
3601 ** percent sign - "%" - followed by exactly two hexadecimal digits
3602 ** specifying an octet value. ^Before the path or query components of a
3603 ** URI filename are interpreted, they are encoded using UTF-8 and all
3604 ** hexadecimal escape sequences replaced by a single byte containing the
3605 ** corresponding octet. If this process generates an invalid UTF-8 encoding,
3606 ** the results are undefined.
3607 **
3608 ** <b>Note to Windows users:</b>  The encoding used for the filename argument
3609 ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
3610 ** codepage is currently defined.  Filenames containing international
3611 ** characters must be converted to UTF-8 prior to passing them into
3612 ** sqlite3_open() or sqlite3_open_v2().
3613 **
3614 ** <b>Note to Windows Runtime users:</b>  The temporary directory must be set
3615 ** prior to calling sqlite3_open() or sqlite3_open_v2().  Otherwise, various
3616 ** features that require the use of temporary files may fail.
3617 **
3618 ** See also: [sqlite3_temp_directory]
3619 */
3620 SQLITE_API int sqlite3_open(
3621   const char *filename,   /* Database filename (UTF-8) */
3622   sqlite3 **ppDb          /* OUT: SQLite db handle */
3623 );
3624 SQLITE_API int sqlite3_open16(
3625   const void *filename,   /* Database filename (UTF-16) */
3626   sqlite3 **ppDb          /* OUT: SQLite db handle */
3627 );
3628 SQLITE_API int sqlite3_open_v2(
3629   const char *filename,   /* Database filename (UTF-8) */
3630   sqlite3 **ppDb,         /* OUT: SQLite db handle */
3631   int flags,              /* Flags */
3632   const char *zVfs        /* Name of VFS module to use */
3633 );
3634 
3635 /*
3636 ** CAPI3REF: Obtain Values For URI Parameters
3637 **
3638 ** These are utility routines, useful to [VFS|custom VFS implementations],
3639 ** that check if a database file was a URI that contained a specific query
3640 ** parameter, and if so obtains the value of that query parameter.
3641 **
3642 ** The first parameter to these interfaces (hereafter referred to
3643 ** as F) must be one of:
3644 ** <ul>
3645 ** <li> A database filename pointer created by the SQLite core and
3646 ** passed into the xOpen() method of a VFS implemention, or
3647 ** <li> A filename obtained from [sqlite3_db_filename()], or
3648 ** <li> A new filename constructed using [sqlite3_create_filename()].
3649 ** </ul>
3650 ** If the F parameter is not one of the above, then the behavior is
3651 ** undefined and probably undesirable.  Older versions of SQLite were
3652 ** more tolerant of invalid F parameters than newer versions.
3653 **
3654 ** If F is a suitable filename (as described in the previous paragraph)
3655 ** and if P is the name of the query parameter, then
3656 ** sqlite3_uri_parameter(F,P) returns the value of the P
3657 ** parameter if it exists or a NULL pointer if P does not appear as a
3658 ** query parameter on F.  If P is a query parameter of F and it
3659 ** has no explicit value, then sqlite3_uri_parameter(F,P) returns
3660 ** a pointer to an empty string.
3661 **
3662 ** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
3663 ** parameter and returns true (1) or false (0) according to the value
3664 ** of P.  The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
3665 ** value of query parameter P is one of "yes", "true", or "on" in any
3666 ** case or if the value begins with a non-zero number.  The
3667 ** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
3668 ** query parameter P is one of "no", "false", or "off" in any case or
3669 ** if the value begins with a numeric zero.  If P is not a query
3670 ** parameter on F or if the value of P does not match any of the
3671 ** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).
3672 **
3673 ** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
3674 ** 64-bit signed integer and returns that integer, or D if P does not
3675 ** exist.  If the value of P is something other than an integer, then
3676 ** zero is returned.
3677 **
3678 ** The sqlite3_uri_key(F,N) returns a pointer to the name (not
3679 ** the value) of the N-th query parameter for filename F, or a NULL
3680 ** pointer if N is less than zero or greater than the number of query
3681 ** parameters minus 1.  The N value is zero-based so N should be 0 to obtain
3682 ** the name of the first query parameter, 1 for the second parameter, and
3683 ** so forth.
3684 **
3685 ** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
3686 ** sqlite3_uri_boolean(F,P,B) returns B.  If F is not a NULL pointer and
3687 ** is not a database file pathname pointer that the SQLite core passed
3688 ** into the xOpen VFS method, then the behavior of this routine is undefined
3689 ** and probably undesirable.
3690 **
3691 ** Beginning with SQLite [version 3.31.0] ([dateof:3.31.0]) the input F
3692 ** parameter can also be the name of a rollback journal file or WAL file
3693 ** in addition to the main database file.  Prior to version 3.31.0, these
3694 ** routines would only work if F was the name of the main database file.
3695 ** When the F parameter is the name of the rollback journal or WAL file,
3696 ** it has access to all the same query parameters as were found on the
3697 ** main database file.
3698 **
3699 ** See the [URI filename] documentation for additional information.
3700 */
3701 SQLITE_API const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam);
3702 SQLITE_API int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault);
3703 SQLITE_API sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64);
3704 SQLITE_API const char *sqlite3_uri_key(const char *zFilename, int N);
3705 
3706 /*
3707 ** CAPI3REF:  Translate filenames
3708 **
3709 ** These routines are available to [VFS|custom VFS implementations] for
3710 ** translating filenames between the main database file, the journal file,
3711 ** and the WAL file.
3712 **
3713 ** If F is the name of an sqlite database file, journal file, or WAL file
3714 ** passed by the SQLite core into the VFS, then sqlite3_filename_database(F)
3715 ** returns the name of the corresponding database file.
3716 **
3717 ** If F is the name of an sqlite database file, journal file, or WAL file
3718 ** passed by the SQLite core into the VFS, or if F is a database filename
3719 ** obtained from [sqlite3_db_filename()], then sqlite3_filename_journal(F)
3720 ** returns the name of the corresponding rollback journal file.
3721 **
3722 ** If F is the name of an sqlite database file, journal file, or WAL file
3723 ** that was passed by the SQLite core into the VFS, or if F is a database
3724 ** filename obtained from [sqlite3_db_filename()], then
3725 ** sqlite3_filename_wal(F) returns the name of the corresponding
3726 ** WAL file.
3727 **
3728 ** In all of the above, if F is not the name of a database, journal or WAL
3729 ** filename passed into the VFS from the SQLite core and F is not the
3730 ** return value from [sqlite3_db_filename()], then the result is
3731 ** undefined and is likely a memory access violation.
3732 */
3733 SQLITE_API const char *sqlite3_filename_database(const char*);
3734 SQLITE_API const char *sqlite3_filename_journal(const char*);
3735 SQLITE_API const char *sqlite3_filename_wal(const char*);
3736 
3737 /*
3738 ** CAPI3REF:  Database File Corresponding To A Journal
3739 **
3740 ** ^If X is the name of a rollback or WAL-mode journal file that is
3741 ** passed into the xOpen method of [sqlite3_vfs], then
3742 ** sqlite3_database_file_object(X) returns a pointer to the [sqlite3_file]
3743 ** object that represents the main database file.
3744 **
3745 ** This routine is intended for use in custom [VFS] implementations
3746 ** only.  It is not a general-purpose interface.
3747 ** The argument sqlite3_file_object(X) must be a filename pointer that
3748 ** has been passed into [sqlite3_vfs].xOpen method where the
3749 ** flags parameter to xOpen contains one of the bits
3750 ** [SQLITE_OPEN_MAIN_JOURNAL] or [SQLITE_OPEN_WAL].  Any other use
3751 ** of this routine results in undefined and probably undesirable
3752 ** behavior.
3753 */
3754 SQLITE_API sqlite3_file *sqlite3_database_file_object(const char*);
3755 
3756 /*
3757 ** CAPI3REF: Create and Destroy VFS Filenames
3758 **
3759 ** These interfces are provided for use by [VFS shim] implementations and
3760 ** are not useful outside of that context.
3761 **
3762 ** The sqlite3_create_filename(D,J,W,N,P) allocates memory to hold a version of
3763 ** database filename D with corresponding journal file J and WAL file W and
3764 ** with N URI parameters key/values pairs in the array P.  The result from
3765 ** sqlite3_create_filename(D,J,W,N,P) is a pointer to a database filename that
3766 ** is safe to pass to routines like:
3767 ** <ul>
3768 ** <li> [sqlite3_uri_parameter()],
3769 ** <li> [sqlite3_uri_boolean()],
3770 ** <li> [sqlite3_uri_int64()],
3771 ** <li> [sqlite3_uri_key()],
3772 ** <li> [sqlite3_filename_database()],
3773 ** <li> [sqlite3_filename_journal()], or
3774 ** <li> [sqlite3_filename_wal()].
3775 ** </ul>
3776 ** If a memory allocation error occurs, sqlite3_create_filename() might
3777 ** return a NULL pointer.  The memory obtained from sqlite3_create_filename(X)
3778 ** must be released by a corresponding call to sqlite3_free_filename(Y).
3779 **
3780 ** The P parameter in sqlite3_create_filename(D,J,W,N,P) should be an array
3781 ** of 2*N pointers to strings.  Each pair of pointers in this array corresponds
3782 ** to a key and value for a query parameter.  The P parameter may be a NULL
3783 ** pointer if N is zero.  None of the 2*N pointers in the P array may be
3784 ** NULL pointers and key pointers should not be empty strings.
3785 ** None of the D, J, or W parameters to sqlite3_create_filename(D,J,W,N,P) may
3786 ** be NULL pointers, though they can be empty strings.
3787 **
3788 ** The sqlite3_free_filename(Y) routine releases a memory allocation
3789 ** previously obtained from sqlite3_create_filename().  Invoking
3790 ** sqlite3_free_filename(Y) where Y is a NULL pointer is a harmless no-op.
3791 **
3792 ** If the Y parameter to sqlite3_free_filename(Y) is anything other
3793 ** than a NULL pointer or a pointer previously acquired from
3794 ** sqlite3_create_filename(), then bad things such as heap
3795 ** corruption or segfaults may occur. The value Y should not be
3796 ** used again after sqlite3_free_filename(Y) has been called.  This means
3797 ** that if the [sqlite3_vfs.xOpen()] method of a VFS has been called using Y,
3798 ** then the corresponding [sqlite3_module.xClose() method should also be
3799 ** invoked prior to calling sqlite3_free_filename(Y).
3800 */
3801 SQLITE_API char *sqlite3_create_filename(
3802   const char *zDatabase,
3803   const char *zJournal,
3804   const char *zWal,
3805   int nParam,
3806   const char **azParam
3807 );
3808 SQLITE_API void sqlite3_free_filename(char*);
3809 
3810 /*
3811 ** CAPI3REF: Error Codes And Messages
3812 ** METHOD: sqlite3
3813 **
3814 ** ^If the most recent sqlite3_* API call associated with
3815 ** [database connection] D failed, then the sqlite3_errcode(D) interface
3816 ** returns the numeric [result code] or [extended result code] for that
3817 ** API call.
3818 ** ^The sqlite3_extended_errcode()
3819 ** interface is the same except that it always returns the
3820 ** [extended result code] even when extended result codes are
3821 ** disabled.
3822 **
3823 ** The values returned by sqlite3_errcode() and/or
3824 ** sqlite3_extended_errcode() might change with each API call.
3825 ** Except, there are some interfaces that are guaranteed to never
3826 ** change the value of the error code.  The error-code preserving
3827 ** interfaces include the following:
3828 **
3829 ** <ul>
3830 ** <li> sqlite3_errcode()
3831 ** <li> sqlite3_extended_errcode()
3832 ** <li> sqlite3_errmsg()
3833 ** <li> sqlite3_errmsg16()
3834 ** <li> sqlite3_error_offset()
3835 ** </ul>
3836 **
3837 ** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
3838 ** text that describes the error, as either UTF-8 or UTF-16 respectively.
3839 ** ^(Memory to hold the error message string is managed internally.
3840 ** The application does not need to worry about freeing the result.
3841 ** However, the error string might be overwritten or deallocated by
3842 ** subsequent calls to other SQLite interface functions.)^
3843 **
3844 ** ^The sqlite3_errstr() interface returns the English-language text
3845 ** that describes the [result code], as UTF-8.
3846 ** ^(Memory to hold the error message string is managed internally
3847 ** and must not be freed by the application)^.
3848 **
3849 ** ^If the most recent error references a specific token in the input
3850 ** SQL, the sqlite3_error_offset() interface returns the byte offset
3851 ** of the start of that token.  ^The byte offset returned by
3852 ** sqlite3_error_offset() assumes that the input SQL is UTF8.
3853 ** ^If the most recent error does not reference a specific token in the input
3854 ** SQL, then the sqlite3_error_offset() function returns -1.
3855 **
3856 ** When the serialized [threading mode] is in use, it might be the
3857 ** case that a second error occurs on a separate thread in between
3858 ** the time of the first error and the call to these interfaces.
3859 ** When that happens, the second error will be reported since these
3860 ** interfaces always report the most recent result.  To avoid
3861 ** this, each thread can obtain exclusive use of the [database connection] D
3862 ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
3863 ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
3864 ** all calls to the interfaces listed here are completed.
3865 **
3866 ** If an interface fails with SQLITE_MISUSE, that means the interface
3867 ** was invoked incorrectly by the application.  In that case, the
3868 ** error code and message may or may not be set.
3869 */
3870 SQLITE_API int sqlite3_errcode(sqlite3 *db);
3871 SQLITE_API int sqlite3_extended_errcode(sqlite3 *db);
3872 SQLITE_API const char *sqlite3_errmsg(sqlite3*);
3873 SQLITE_API const void *sqlite3_errmsg16(sqlite3*);
3874 SQLITE_API const char *sqlite3_errstr(int);
3875 SQLITE_API int sqlite3_error_offset(sqlite3 *db);
3876 
3877 /*
3878 ** CAPI3REF: Prepared Statement Object
3879 ** KEYWORDS: {prepared statement} {prepared statements}
3880 **
3881 ** An instance of this object represents a single SQL statement that
3882 ** has been compiled into binary form and is ready to be evaluated.
3883 **
3884 ** Think of each SQL statement as a separate computer program.  The
3885 ** original SQL text is source code.  A prepared statement object
3886 ** is the compiled object code.  All SQL must be converted into a
3887 ** prepared statement before it can be run.
3888 **
3889 ** The life-cycle of a prepared statement object usually goes like this:
3890 **
3891 ** <ol>
3892 ** <li> Create the prepared statement object using [sqlite3_prepare_v2()].
3893 ** <li> Bind values to [parameters] using the sqlite3_bind_*()
3894 **      interfaces.
3895 ** <li> Run the SQL by calling [sqlite3_step()] one or more times.
3896 ** <li> Reset the prepared statement using [sqlite3_reset()] then go back
3897 **      to step 2.  Do this zero or more times.
3898 ** <li> Destroy the object using [sqlite3_finalize()].
3899 ** </ol>
3900 */
3901 typedef struct sqlite3_stmt sqlite3_stmt;
3902 
3903 /*
3904 ** CAPI3REF: Run-time Limits
3905 ** METHOD: sqlite3
3906 **
3907 ** ^(This interface allows the size of various constructs to be limited
3908 ** on a connection by connection basis.  The first parameter is the
3909 ** [database connection] whose limit is to be set or queried.  The
3910 ** second parameter is one of the [limit categories] that define a
3911 ** class of constructs to be size limited.  The third parameter is the
3912 ** new limit for that construct.)^
3913 **
3914 ** ^If the new limit is a negative number, the limit is unchanged.
3915 ** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
3916 ** [limits | hard upper bound]
3917 ** set at compile-time by a C preprocessor macro called
3918 ** [limits | SQLITE_MAX_<i>NAME</i>].
3919 ** (The "_LIMIT_" in the name is changed to "_MAX_".))^
3920 ** ^Attempts to increase a limit above its hard upper bound are
3921 ** silently truncated to the hard upper bound.
3922 **
3923 ** ^Regardless of whether or not the limit was changed, the
3924 ** [sqlite3_limit()] interface returns the prior value of the limit.
3925 ** ^Hence, to find the current value of a limit without changing it,
3926 ** simply invoke this interface with the third parameter set to -1.
3927 **
3928 ** Run-time limits are intended for use in applications that manage
3929 ** both their own internal database and also databases that are controlled
3930 ** by untrusted external sources.  An example application might be a
3931 ** web browser that has its own databases for storing history and
3932 ** separate databases controlled by JavaScript applications downloaded
3933 ** off the Internet.  The internal databases can be given the
3934 ** large, default limits.  Databases managed by external sources can
3935 ** be given much smaller limits designed to prevent a denial of service
3936 ** attack.  Developers might also want to use the [sqlite3_set_authorizer()]
3937 ** interface to further control untrusted SQL.  The size of the database
3938 ** created by an untrusted script can be contained using the
3939 ** [max_page_count] [PRAGMA].
3940 **
3941 ** New run-time limit categories may be added in future releases.
3942 */
3943 SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal);
3944 
3945 /*
3946 ** CAPI3REF: Run-Time Limit Categories
3947 ** KEYWORDS: {limit category} {*limit categories}
3948 **
3949 ** These constants define various performance limits
3950 ** that can be lowered at run-time using [sqlite3_limit()].
3951 ** The synopsis of the meanings of the various limits is shown below.
3952 ** Additional information is available at [limits | Limits in SQLite].
3953 **
3954 ** <dl>
3955 ** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt>
3956 ** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
3957 **
3958 ** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
3959 ** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
3960 **
3961 ** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt>
3962 ** <dd>The maximum number of columns in a table definition or in the
3963 ** result set of a [SELECT] or the maximum number of columns in an index
3964 ** or in an ORDER BY or GROUP BY clause.</dd>)^
3965 **
3966 ** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
3967 ** <dd>The maximum depth of the parse tree on any expression.</dd>)^
3968 **
3969 ** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
3970 ** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
3971 **
3972 ** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
3973 ** <dd>The maximum number of instructions in a virtual machine program
3974 ** used to implement an SQL statement.  If [sqlite3_prepare_v2()] or
3975 ** the equivalent tries to allocate space for more than this many opcodes
3976 ** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^
3977 **
3978 ** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
3979 ** <dd>The maximum number of arguments on a function.</dd>)^
3980 **
3981 ** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
3982 ** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
3983 **
3984 ** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]]
3985 ** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
3986 ** <dd>The maximum length of the pattern argument to the [LIKE] or
3987 ** [GLOB] operators.</dd>)^
3988 **
3989 ** [[SQLITE_LIMIT_VARIABLE_NUMBER]]
3990 ** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
3991 ** <dd>The maximum index number of any [parameter] in an SQL statement.)^
3992 **
3993 ** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
3994 ** <dd>The maximum depth of recursion for triggers.</dd>)^
3995 **
3996 ** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt>
3997 ** <dd>The maximum number of auxiliary worker threads that a single
3998 ** [prepared statement] may start.</dd>)^
3999 ** </dl>
4000 */
4001 #define SQLITE_LIMIT_LENGTH                    0
4002 #define SQLITE_LIMIT_SQL_LENGTH                1
4003 #define SQLITE_LIMIT_COLUMN                    2
4004 #define SQLITE_LIMIT_EXPR_DEPTH                3
4005 #define SQLITE_LIMIT_COMPOUND_SELECT           4
4006 #define SQLITE_LIMIT_VDBE_OP                   5
4007 #define SQLITE_LIMIT_FUNCTION_ARG              6
4008 #define SQLITE_LIMIT_ATTACHED                  7
4009 #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH       8
4010 #define SQLITE_LIMIT_VARIABLE_NUMBER           9
4011 #define SQLITE_LIMIT_TRIGGER_DEPTH            10
4012 #define SQLITE_LIMIT_WORKER_THREADS           11
4013 
4014 /*
4015 ** CAPI3REF: Prepare Flags
4016 **
4017 ** These constants define various flags that can be passed into
4018 ** "prepFlags" parameter of the [sqlite3_prepare_v3()] and
4019 ** [sqlite3_prepare16_v3()] interfaces.
4020 **
4021 ** New flags may be added in future releases of SQLite.
4022 **
4023 ** <dl>
4024 ** [[SQLITE_PREPARE_PERSISTENT]] ^(<dt>SQLITE_PREPARE_PERSISTENT</dt>
4025 ** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner
4026 ** that the prepared statement will be retained for a long time and
4027 ** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()]
4028 ** and [sqlite3_prepare16_v3()] assume that the prepared statement will
4029 ** be used just once or at most a few times and then destroyed using
4030 ** [sqlite3_finalize()] relatively soon. The current implementation acts
4031 ** on this hint by avoiding the use of [lookaside memory] so as not to
4032 ** deplete the limited store of lookaside memory. Future versions of
4033 ** SQLite may act on this hint differently.
4034 **
4035 ** [[SQLITE_PREPARE_NORMALIZE]] <dt>SQLITE_PREPARE_NORMALIZE</dt>
4036 ** <dd>The SQLITE_PREPARE_NORMALIZE flag is a no-op. This flag used
4037 ** to be required for any prepared statement that wanted to use the
4038 ** [sqlite3_normalized_sql()] interface.  However, the
4039 ** [sqlite3_normalized_sql()] interface is now available to all
4040 ** prepared statements, regardless of whether or not they use this
4041 ** flag.
4042 **
4043 ** [[SQLITE_PREPARE_NO_VTAB]] <dt>SQLITE_PREPARE_NO_VTAB</dt>
4044 ** <dd>The SQLITE_PREPARE_NO_VTAB flag causes the SQL compiler
4045 ** to return an error (error code SQLITE_ERROR) if the statement uses
4046 ** any virtual tables.
4047 ** </dl>
4048 */
4049 #define SQLITE_PREPARE_PERSISTENT              0x01
4050 #define SQLITE_PREPARE_NORMALIZE               0x02
4051 #define SQLITE_PREPARE_NO_VTAB                 0x04
4052 
4053 /*
4054 ** CAPI3REF: Compiling An SQL Statement
4055 ** KEYWORDS: {SQL statement compiler}
4056 ** METHOD: sqlite3
4057 ** CONSTRUCTOR: sqlite3_stmt
4058 **
4059 ** To execute an SQL statement, it must first be compiled into a byte-code
4060 ** program using one of these routines.  Or, in other words, these routines
4061 ** are constructors for the [prepared statement] object.
4062 **
4063 ** The preferred routine to use is [sqlite3_prepare_v2()].  The
4064 ** [sqlite3_prepare()] interface is legacy and should be avoided.
4065 ** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used
4066 ** for special purposes.
4067 **
4068 ** The use of the UTF-8 interfaces is preferred, as SQLite currently
4069 ** does all parsing using UTF-8.  The UTF-16 interfaces are provided
4070 ** as a convenience.  The UTF-16 interfaces work by converting the
4071 ** input text into UTF-8, then invoking the corresponding UTF-8 interface.
4072 **
4073 ** The first argument, "db", is a [database connection] obtained from a
4074 ** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
4075 ** [sqlite3_open16()].  The database connection must not have been closed.
4076 **
4077 ** The second argument, "zSql", is the statement to be compiled, encoded
4078 ** as either UTF-8 or UTF-16.  The sqlite3_prepare(), sqlite3_prepare_v2(),
4079 ** and sqlite3_prepare_v3()
4080 ** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(),
4081 ** and sqlite3_prepare16_v3() use UTF-16.
4082 **
4083 ** ^If the nByte argument is negative, then zSql is read up to the
4084 ** first zero terminator. ^If nByte is positive, then it is the
4085 ** number of bytes read from zSql.  ^If nByte is zero, then no prepared
4086 ** statement is generated.
4087 ** If the caller knows that the supplied string is nul-terminated, then
4088 ** there is a small performance advantage to passing an nByte parameter that
4089 ** is the number of bytes in the input string <i>including</i>
4090 ** the nul-terminator.
4091 **
4092 ** ^If pzTail is not NULL then *pzTail is made to point to the first byte
4093 ** past the end of the first SQL statement in zSql.  These routines only
4094 ** compile the first statement in zSql, so *pzTail is left pointing to
4095 ** what remains uncompiled.
4096 **
4097 ** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
4098 ** executed using [sqlite3_step()].  ^If there is an error, *ppStmt is set
4099 ** to NULL.  ^If the input text contains no SQL (if the input is an empty
4100 ** string or a comment) then *ppStmt is set to NULL.
4101 ** The calling procedure is responsible for deleting the compiled
4102 ** SQL statement using [sqlite3_finalize()] after it has finished with it.
4103 ** ppStmt may not be NULL.
4104 **
4105 ** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
4106 ** otherwise an [error code] is returned.
4107 **
4108 ** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(),
4109 ** and sqlite3_prepare16_v3() interfaces are recommended for all new programs.
4110 ** The older interfaces (sqlite3_prepare() and sqlite3_prepare16())
4111 ** are retained for backwards compatibility, but their use is discouraged.
4112 ** ^In the "vX" interfaces, the prepared statement
4113 ** that is returned (the [sqlite3_stmt] object) contains a copy of the
4114 ** original SQL text. This causes the [sqlite3_step()] interface to
4115 ** behave differently in three ways:
4116 **
4117 ** <ol>
4118 ** <li>
4119 ** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
4120 ** always used to do, [sqlite3_step()] will automatically recompile the SQL
4121 ** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY]
4122 ** retries will occur before sqlite3_step() gives up and returns an error.
4123 ** </li>
4124 **
4125 ** <li>
4126 ** ^When an error occurs, [sqlite3_step()] will return one of the detailed
4127 ** [error codes] or [extended error codes].  ^The legacy behavior was that
4128 ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
4129 ** and the application would have to make a second call to [sqlite3_reset()]
4130 ** in order to find the underlying cause of the problem. With the "v2" prepare
4131 ** interfaces, the underlying reason for the error is returned immediately.
4132 ** </li>
4133 **
4134 ** <li>
4135 ** ^If the specific value bound to a [parameter | host parameter] in the
4136 ** WHERE clause might influence the choice of query plan for a statement,
4137 ** then the statement will be automatically recompiled, as if there had been
4138 ** a schema change, on the first [sqlite3_step()] call following any change
4139 ** to the [sqlite3_bind_text | bindings] of that [parameter].
4140 ** ^The specific value of a WHERE-clause [parameter] might influence the
4141 ** choice of query plan if the parameter is the left-hand side of a [LIKE]
4142 ** or [GLOB] operator or if the parameter is compared to an indexed column
4143 ** and the [SQLITE_ENABLE_STAT4] compile-time option is enabled.
4144 ** </li>
4145 ** </ol>
4146 **
4147 ** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having
4148 ** the extra prepFlags parameter, which is a bit array consisting of zero or
4149 ** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags.  ^The
4150 ** sqlite3_prepare_v2() interface works exactly the same as
4151 ** sqlite3_prepare_v3() with a zero prepFlags parameter.
4152 */
4153 SQLITE_API int sqlite3_prepare(
4154   sqlite3 *db,            /* Database handle */
4155   const char *zSql,       /* SQL statement, UTF-8 encoded */
4156   int nByte,              /* Maximum length of zSql in bytes. */
4157   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
4158   const char **pzTail     /* OUT: Pointer to unused portion of zSql */
4159 );
4160 SQLITE_API int sqlite3_prepare_v2(
4161   sqlite3 *db,            /* Database handle */
4162   const char *zSql,       /* SQL statement, UTF-8 encoded */
4163   int nByte,              /* Maximum length of zSql in bytes. */
4164   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
4165   const char **pzTail     /* OUT: Pointer to unused portion of zSql */
4166 );
4167 SQLITE_API int sqlite3_prepare_v3(
4168   sqlite3 *db,            /* Database handle */
4169   const char *zSql,       /* SQL statement, UTF-8 encoded */
4170   int nByte,              /* Maximum length of zSql in bytes. */
4171   unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
4172   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
4173   const char **pzTail     /* OUT: Pointer to unused portion of zSql */
4174 );
4175 SQLITE_API int sqlite3_prepare16(
4176   sqlite3 *db,            /* Database handle */
4177   const void *zSql,       /* SQL statement, UTF-16 encoded */
4178   int nByte,              /* Maximum length of zSql in bytes. */
4179   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
4180   const void **pzTail     /* OUT: Pointer to unused portion of zSql */
4181 );
4182 SQLITE_API int sqlite3_prepare16_v2(
4183   sqlite3 *db,            /* Database handle */
4184   const void *zSql,       /* SQL statement, UTF-16 encoded */
4185   int nByte,              /* Maximum length of zSql in bytes. */
4186   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
4187   const void **pzTail     /* OUT: Pointer to unused portion of zSql */
4188 );
4189 SQLITE_API int sqlite3_prepare16_v3(
4190   sqlite3 *db,            /* Database handle */
4191   const void *zSql,       /* SQL statement, UTF-16 encoded */
4192   int nByte,              /* Maximum length of zSql in bytes. */
4193   unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
4194   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
4195   const void **pzTail     /* OUT: Pointer to unused portion of zSql */
4196 );
4197 
4198 /*
4199 ** CAPI3REF: Retrieving Statement SQL
4200 ** METHOD: sqlite3_stmt
4201 **
4202 ** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8
4203 ** SQL text used to create [prepared statement] P if P was
4204 ** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()],
4205 ** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()].
4206 ** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8
4207 ** string containing the SQL text of prepared statement P with
4208 ** [bound parameters] expanded.
4209 ** ^The sqlite3_normalized_sql(P) interface returns a pointer to a UTF-8
4210 ** string containing the normalized SQL text of prepared statement P.  The
4211 ** semantics used to normalize a SQL statement are unspecified and subject
4212 ** to change.  At a minimum, literal values will be replaced with suitable
4213 ** placeholders.
4214 **
4215 ** ^(For example, if a prepared statement is created using the SQL
4216 ** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345
4217 ** and parameter :xyz is unbound, then sqlite3_sql() will return
4218 ** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql()
4219 ** will return "SELECT 2345,NULL".)^
4220 **
4221 ** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory
4222 ** is available to hold the result, or if the result would exceed the
4223 ** the maximum string length determined by the [SQLITE_LIMIT_LENGTH].
4224 **
4225 ** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of
4226 ** bound parameter expansions.  ^The [SQLITE_OMIT_TRACE] compile-time
4227 ** option causes sqlite3_expanded_sql() to always return NULL.
4228 **
4229 ** ^The strings returned by sqlite3_sql(P) and sqlite3_normalized_sql(P)
4230 ** are managed by SQLite and are automatically freed when the prepared
4231 ** statement is finalized.
4232 ** ^The string returned by sqlite3_expanded_sql(P), on the other hand,
4233 ** is obtained from [sqlite3_malloc()] and must be freed by the application
4234 ** by passing it to [sqlite3_free()].
4235 **
4236 ** ^The sqlite3_normalized_sql() interface is only available if
4237 ** the [SQLITE_ENABLE_NORMALIZE] compile-time option is defined.
4238 */
4239 SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt);
4240 SQLITE_API char *sqlite3_expanded_sql(sqlite3_stmt *pStmt);
4241 #ifdef SQLITE_ENABLE_NORMALIZE
4242 SQLITE_API const char *sqlite3_normalized_sql(sqlite3_stmt *pStmt);
4243 #endif
4244 
4245 /*
4246 ** CAPI3REF: Determine If An SQL Statement Writes The Database
4247 ** METHOD: sqlite3_stmt
4248 **
4249 ** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
4250 ** and only if the [prepared statement] X makes no direct changes to
4251 ** the content of the database file.
4252 **
4253 ** Note that [application-defined SQL functions] or
4254 ** [virtual tables] might change the database indirectly as a side effect.
4255 ** ^(For example, if an application defines a function "eval()" that
4256 ** calls [sqlite3_exec()], then the following SQL statement would
4257 ** change the database file through side-effects:
4258 **
4259 ** <blockquote><pre>
4260 **    SELECT eval('DELETE FROM t1') FROM t2;
4261 ** </pre></blockquote>
4262 **
4263 ** But because the [SELECT] statement does not change the database file
4264 ** directly, sqlite3_stmt_readonly() would still return true.)^
4265 **
4266 ** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
4267 ** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
4268 ** since the statements themselves do not actually modify the database but
4269 ** rather they control the timing of when other statements modify the
4270 ** database.  ^The [ATTACH] and [DETACH] statements also cause
4271 ** sqlite3_stmt_readonly() to return true since, while those statements
4272 ** change the configuration of a database connection, they do not make
4273 ** changes to the content of the database files on disk.
4274 ** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since
4275 ** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and
4276 ** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so
4277 ** sqlite3_stmt_readonly() returns false for those commands.
4278 **
4279 ** ^This routine returns false if there is any possibility that the
4280 ** statement might change the database file.  ^A false return does
4281 ** not guarantee that the statement will change the database file.
4282 ** ^For example, an UPDATE statement might have a WHERE clause that
4283 ** makes it a no-op, but the sqlite3_stmt_readonly() result would still
4284 ** be false.  ^Similarly, a CREATE TABLE IF NOT EXISTS statement is a
4285 ** read-only no-op if the table already exists, but
4286 ** sqlite3_stmt_readonly() still returns false for such a statement.
4287 **
4288 ** ^If prepared statement X is an [EXPLAIN] or [EXPLAIN QUERY PLAN]
4289 ** statement, then sqlite3_stmt_readonly(X) returns the same value as
4290 ** if the EXPLAIN or EXPLAIN QUERY PLAN prefix were omitted.
4291 */
4292 SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
4293 
4294 /*
4295 ** CAPI3REF: Query The EXPLAIN Setting For A Prepared Statement
4296 ** METHOD: sqlite3_stmt
4297 **
4298 ** ^The sqlite3_stmt_isexplain(S) interface returns 1 if the
4299 ** prepared statement S is an EXPLAIN statement, or 2 if the
4300 ** statement S is an EXPLAIN QUERY PLAN.
4301 ** ^The sqlite3_stmt_isexplain(S) interface returns 0 if S is
4302 ** an ordinary statement or a NULL pointer.
4303 */
4304 SQLITE_API int sqlite3_stmt_isexplain(sqlite3_stmt *pStmt);
4305 
4306 /*
4307 ** CAPI3REF: Determine If A Prepared Statement Has Been Reset
4308 ** METHOD: sqlite3_stmt
4309 **
4310 ** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
4311 ** [prepared statement] S has been stepped at least once using
4312 ** [sqlite3_step(S)] but has neither run to completion (returned
4313 ** [SQLITE_DONE] from [sqlite3_step(S)]) nor
4314 ** been reset using [sqlite3_reset(S)].  ^The sqlite3_stmt_busy(S)
4315 ** interface returns false if S is a NULL pointer.  If S is not a
4316 ** NULL pointer and is not a pointer to a valid [prepared statement]
4317 ** object, then the behavior is undefined and probably undesirable.
4318 **
4319 ** This interface can be used in combination [sqlite3_next_stmt()]
4320 ** to locate all prepared statements associated with a database
4321 ** connection that are in need of being reset.  This can be used,
4322 ** for example, in diagnostic routines to search for prepared
4323 ** statements that are holding a transaction open.
4324 */
4325 SQLITE_API int sqlite3_stmt_busy(sqlite3_stmt*);
4326 
4327 /*
4328 ** CAPI3REF: Dynamically Typed Value Object
4329 ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
4330 **
4331 ** SQLite uses the sqlite3_value object to represent all values
4332 ** that can be stored in a database table. SQLite uses dynamic typing
4333 ** for the values it stores.  ^Values stored in sqlite3_value objects
4334 ** can be integers, floating point values, strings, BLOBs, or NULL.
4335 **
4336 ** An sqlite3_value object may be either "protected" or "unprotected".
4337 ** Some interfaces require a protected sqlite3_value.  Other interfaces
4338 ** will accept either a protected or an unprotected sqlite3_value.
4339 ** Every interface that accepts sqlite3_value arguments specifies
4340 ** whether or not it requires a protected sqlite3_value.  The
4341 ** [sqlite3_value_dup()] interface can be used to construct a new
4342 ** protected sqlite3_value from an unprotected sqlite3_value.
4343 **
4344 ** The terms "protected" and "unprotected" refer to whether or not
4345 ** a mutex is held.  An internal mutex is held for a protected
4346 ** sqlite3_value object but no mutex is held for an unprotected
4347 ** sqlite3_value object.  If SQLite is compiled to be single-threaded
4348 ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
4349 ** or if SQLite is run in one of reduced mutex modes
4350 ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
4351 ** then there is no distinction between protected and unprotected
4352 ** sqlite3_value objects and they can be used interchangeably.  However,
4353 ** for maximum code portability it is recommended that applications
4354 ** still make the distinction between protected and unprotected
4355 ** sqlite3_value objects even when not strictly required.
4356 **
4357 ** ^The sqlite3_value objects that are passed as parameters into the
4358 ** implementation of [application-defined SQL functions] are protected.
4359 ** ^The sqlite3_value objects returned by [sqlite3_vtab_rhs_value()]
4360 ** are protected.
4361 ** ^The sqlite3_value object returned by
4362 ** [sqlite3_column_value()] is unprotected.
4363 ** Unprotected sqlite3_value objects may only be used as arguments
4364 ** to [sqlite3_result_value()], [sqlite3_bind_value()], and
4365 ** [sqlite3_value_dup()].
4366 ** The [sqlite3_value_blob | sqlite3_value_type()] family of
4367 ** interfaces require protected sqlite3_value objects.
4368 */
4369 typedef struct sqlite3_value sqlite3_value;
4370 
4371 /*
4372 ** CAPI3REF: SQL Function Context Object
4373 **
4374 ** The context in which an SQL function executes is stored in an
4375 ** sqlite3_context object.  ^A pointer to an sqlite3_context object
4376 ** is always first parameter to [application-defined SQL functions].
4377 ** The application-defined SQL function implementation will pass this
4378 ** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
4379 ** [sqlite3_aggregate_context()], [sqlite3_user_data()],
4380 ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
4381 ** and/or [sqlite3_set_auxdata()].
4382 */
4383 typedef struct sqlite3_context sqlite3_context;
4384 
4385 /*
4386 ** CAPI3REF: Binding Values To Prepared Statements
4387 ** KEYWORDS: {host parameter} {host parameters} {host parameter name}
4388 ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
4389 ** METHOD: sqlite3_stmt
4390 **
4391 ** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
4392 ** literals may be replaced by a [parameter] that matches one of following
4393 ** templates:
4394 **
4395 ** <ul>
4396 ** <li>  ?
4397 ** <li>  ?NNN
4398 ** <li>  :VVV
4399 ** <li>  @VVV
4400 ** <li>  $VVV
4401 ** </ul>
4402 **
4403 ** In the templates above, NNN represents an integer literal,
4404 ** and VVV represents an alphanumeric identifier.)^  ^The values of these
4405 ** parameters (also called "host parameter names" or "SQL parameters")
4406 ** can be set using the sqlite3_bind_*() routines defined here.
4407 **
4408 ** ^The first argument to the sqlite3_bind_*() routines is always
4409 ** a pointer to the [sqlite3_stmt] object returned from
4410 ** [sqlite3_prepare_v2()] or its variants.
4411 **
4412 ** ^The second argument is the index of the SQL parameter to be set.
4413 ** ^The leftmost SQL parameter has an index of 1.  ^When the same named
4414 ** SQL parameter is used more than once, second and subsequent
4415 ** occurrences have the same index as the first occurrence.
4416 ** ^The index for named parameters can be looked up using the
4417 ** [sqlite3_bind_parameter_index()] API if desired.  ^The index
4418 ** for "?NNN" parameters is the value of NNN.
4419 ** ^The NNN value must be between 1 and the [sqlite3_limit()]
4420 ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 32766).
4421 **
4422 ** ^The third argument is the value to bind to the parameter.
4423 ** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16()
4424 ** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter
4425 ** is ignored and the end result is the same as sqlite3_bind_null().
4426 ** ^If the third parameter to sqlite3_bind_text() is not NULL, then
4427 ** it should be a pointer to well-formed UTF8 text.
4428 ** ^If the third parameter to sqlite3_bind_text16() is not NULL, then
4429 ** it should be a pointer to well-formed UTF16 text.
4430 ** ^If the third parameter to sqlite3_bind_text64() is not NULL, then
4431 ** it should be a pointer to a well-formed unicode string that is
4432 ** either UTF8 if the sixth parameter is SQLITE_UTF8, or UTF16
4433 ** otherwise.
4434 **
4435 ** [[byte-order determination rules]] ^The byte-order of
4436 ** UTF16 input text is determined by the byte-order mark (BOM, U+FEFF)
4437 ** found in first character, which is removed, or in the absence of a BOM
4438 ** the byte order is the native byte order of the host
4439 ** machine for sqlite3_bind_text16() or the byte order specified in
4440 ** the 6th parameter for sqlite3_bind_text64().)^
4441 ** ^If UTF16 input text contains invalid unicode
4442 ** characters, then SQLite might change those invalid characters
4443 ** into the unicode replacement character: U+FFFD.
4444 **
4445 ** ^(In those routines that have a fourth argument, its value is the
4446 ** number of bytes in the parameter.  To be clear: the value is the
4447 ** number of <u>bytes</u> in the value, not the number of characters.)^
4448 ** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()
4449 ** is negative, then the length of the string is
4450 ** the number of bytes up to the first zero terminator.
4451 ** If the fourth parameter to sqlite3_bind_blob() is negative, then
4452 ** the behavior is undefined.
4453 ** If a non-negative fourth parameter is provided to sqlite3_bind_text()
4454 ** or sqlite3_bind_text16() or sqlite3_bind_text64() then
4455 ** that parameter must be the byte offset
4456 ** where the NUL terminator would occur assuming the string were NUL
4457 ** terminated.  If any NUL characters occurs at byte offsets less than
4458 ** the value of the fourth parameter then the resulting string value will
4459 ** contain embedded NULs.  The result of expressions involving strings
4460 ** with embedded NULs is undefined.
4461 **
4462 ** ^The fifth argument to the BLOB and string binding interfaces controls
4463 ** or indicates the lifetime of the object referenced by the third parameter.
4464 ** These three options exist:
4465 ** ^ (1) A destructor to dispose of the BLOB or string after SQLite has finished
4466 ** with it may be passed. ^It is called to dispose of the BLOB or string even
4467 ** if the call to the bind API fails, except the destructor is not called if
4468 ** the third parameter is a NULL pointer or the fourth parameter is negative.
4469 ** ^ (2) The special constant, [SQLITE_STATIC], may be passsed to indicate that
4470 ** the application remains responsible for disposing of the object. ^In this
4471 ** case, the object and the provided pointer to it must remain valid until
4472 ** either the prepared statement is finalized or the same SQL parameter is
4473 ** bound to something else, whichever occurs sooner.
4474 ** ^ (3) The constant, [SQLITE_TRANSIENT], may be passed to indicate that the
4475 ** object is to be copied prior to the return from sqlite3_bind_*(). ^The
4476 ** object and pointer to it must remain valid until then. ^SQLite will then
4477 ** manage the lifetime of its private copy.
4478 **
4479 ** ^The sixth argument to sqlite3_bind_text64() must be one of
4480 ** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]
4481 ** to specify the encoding of the text in the third parameter.  If
4482 ** the sixth argument to sqlite3_bind_text64() is not one of the
4483 ** allowed values shown above, or if the text encoding is different
4484 ** from the encoding specified by the sixth parameter, then the behavior
4485 ** is undefined.
4486 **
4487 ** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
4488 ** is filled with zeroes.  ^A zeroblob uses a fixed amount of memory
4489 ** (just an integer to hold its size) while it is being processed.
4490 ** Zeroblobs are intended to serve as placeholders for BLOBs whose
4491 ** content is later written using
4492 ** [sqlite3_blob_open | incremental BLOB I/O] routines.
4493 ** ^A negative value for the zeroblob results in a zero-length BLOB.
4494 **
4495 ** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in
4496 ** [prepared statement] S to have an SQL value of NULL, but to also be
4497 ** associated with the pointer P of type T.  ^D is either a NULL pointer or
4498 ** a pointer to a destructor function for P. ^SQLite will invoke the
4499 ** destructor D with a single argument of P when it is finished using
4500 ** P.  The T parameter should be a static string, preferably a string
4501 ** literal. The sqlite3_bind_pointer() routine is part of the
4502 ** [pointer passing interface] added for SQLite 3.20.0.
4503 **
4504 ** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
4505 ** for the [prepared statement] or with a prepared statement for which
4506 ** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
4507 ** then the call will return [SQLITE_MISUSE].  If any sqlite3_bind_()
4508 ** routine is passed a [prepared statement] that has been finalized, the
4509 ** result is undefined and probably harmful.
4510 **
4511 ** ^Bindings are not cleared by the [sqlite3_reset()] routine.
4512 ** ^Unbound parameters are interpreted as NULL.
4513 **
4514 ** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
4515 ** [error code] if anything goes wrong.
4516 ** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB
4517 ** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or
4518 ** [SQLITE_MAX_LENGTH].
4519 ** ^[SQLITE_RANGE] is returned if the parameter
4520 ** index is out of range.  ^[SQLITE_NOMEM] is returned if malloc() fails.
4521 **
4522 ** See also: [sqlite3_bind_parameter_count()],
4523 ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
4524 */
4525 SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
4526 SQLITE_API int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64,
4527                         void(*)(void*));
4528 SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double);
4529 SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int);
4530 SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
4531 SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int);
4532 SQLITE_API int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*));
4533 SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
4534 SQLITE_API int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64,
4535                          void(*)(void*), unsigned char encoding);
4536 SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
4537 SQLITE_API int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*));
4538 SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
4539 SQLITE_API int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64);
4540 
4541 /*
4542 ** CAPI3REF: Number Of SQL Parameters
4543 ** METHOD: sqlite3_stmt
4544 **
4545 ** ^This routine can be used to find the number of [SQL parameters]
4546 ** in a [prepared statement].  SQL parameters are tokens of the
4547 ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
4548 ** placeholders for values that are [sqlite3_bind_blob | bound]
4549 ** to the parameters at a later time.
4550 **
4551 ** ^(This routine actually returns the index of the largest (rightmost)
4552 ** parameter. For all forms except ?NNN, this will correspond to the
4553 ** number of unique parameters.  If parameters of the ?NNN form are used,
4554 ** there may be gaps in the list.)^
4555 **
4556 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
4557 ** [sqlite3_bind_parameter_name()], and
4558 ** [sqlite3_bind_parameter_index()].
4559 */
4560 SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*);
4561 
4562 /*
4563 ** CAPI3REF: Name Of A Host Parameter
4564 ** METHOD: sqlite3_stmt
4565 **
4566 ** ^The sqlite3_bind_parameter_name(P,N) interface returns
4567 ** the name of the N-th [SQL parameter] in the [prepared statement] P.
4568 ** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
4569 ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
4570 ** respectively.
4571 ** In other words, the initial ":" or "$" or "@" or "?"
4572 ** is included as part of the name.)^
4573 ** ^Parameters of the form "?" without a following integer have no name
4574 ** and are referred to as "nameless" or "anonymous parameters".
4575 **
4576 ** ^The first host parameter has an index of 1, not 0.
4577 **
4578 ** ^If the value N is out of range or if the N-th parameter is
4579 ** nameless, then NULL is returned.  ^The returned string is
4580 ** always in UTF-8 encoding even if the named parameter was
4581 ** originally specified as UTF-16 in [sqlite3_prepare16()],
4582 ** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()].
4583 **
4584 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
4585 ** [sqlite3_bind_parameter_count()], and
4586 ** [sqlite3_bind_parameter_index()].
4587 */
4588 SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
4589 
4590 /*
4591 ** CAPI3REF: Index Of A Parameter With A Given Name
4592 ** METHOD: sqlite3_stmt
4593 **
4594 ** ^Return the index of an SQL parameter given its name.  ^The
4595 ** index value returned is suitable for use as the second
4596 ** parameter to [sqlite3_bind_blob|sqlite3_bind()].  ^A zero
4597 ** is returned if no matching parameter is found.  ^The parameter
4598 ** name must be given in UTF-8 even if the original statement
4599 ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or
4600 ** [sqlite3_prepare16_v3()].
4601 **
4602 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
4603 ** [sqlite3_bind_parameter_count()], and
4604 ** [sqlite3_bind_parameter_name()].
4605 */
4606 SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
4607 
4608 /*
4609 ** CAPI3REF: Reset All Bindings On A Prepared Statement
4610 ** METHOD: sqlite3_stmt
4611 **
4612 ** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
4613 ** the [sqlite3_bind_blob | bindings] on a [prepared statement].
4614 ** ^Use this routine to reset all host parameters to NULL.
4615 */
4616 SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*);
4617 
4618 /*
4619 ** CAPI3REF: Number Of Columns In A Result Set
4620 ** METHOD: sqlite3_stmt
4621 **
4622 ** ^Return the number of columns in the result set returned by the
4623 ** [prepared statement]. ^If this routine returns 0, that means the
4624 ** [prepared statement] returns no data (for example an [UPDATE]).
4625 ** ^However, just because this routine returns a positive number does not
4626 ** mean that one or more rows of data will be returned.  ^A SELECT statement
4627 ** will always have a positive sqlite3_column_count() but depending on the
4628 ** WHERE clause constraints and the table content, it might return no rows.
4629 **
4630 ** See also: [sqlite3_data_count()]
4631 */
4632 SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt);
4633 
4634 /*
4635 ** CAPI3REF: Column Names In A Result Set
4636 ** METHOD: sqlite3_stmt
4637 **
4638 ** ^These routines return the name assigned to a particular column
4639 ** in the result set of a [SELECT] statement.  ^The sqlite3_column_name()
4640 ** interface returns a pointer to a zero-terminated UTF-8 string
4641 ** and sqlite3_column_name16() returns a pointer to a zero-terminated
4642 ** UTF-16 string.  ^The first parameter is the [prepared statement]
4643 ** that implements the [SELECT] statement. ^The second parameter is the
4644 ** column number.  ^The leftmost column is number 0.
4645 **
4646 ** ^The returned string pointer is valid until either the [prepared statement]
4647 ** is destroyed by [sqlite3_finalize()] or until the statement is automatically
4648 ** reprepared by the first call to [sqlite3_step()] for a particular run
4649 ** or until the next call to
4650 ** sqlite3_column_name() or sqlite3_column_name16() on the same column.
4651 **
4652 ** ^If sqlite3_malloc() fails during the processing of either routine
4653 ** (for example during a conversion from UTF-8 to UTF-16) then a
4654 ** NULL pointer is returned.
4655 **
4656 ** ^The name of a result column is the value of the "AS" clause for
4657 ** that column, if there is an AS clause.  If there is no AS clause
4658 ** then the name of the column is unspecified and may change from
4659 ** one release of SQLite to the next.
4660 */
4661 SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N);
4662 SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N);
4663 
4664 /*
4665 ** CAPI3REF: Source Of Data In A Query Result
4666 ** METHOD: sqlite3_stmt
4667 **
4668 ** ^These routines provide a means to determine the database, table, and
4669 ** table column that is the origin of a particular result column in
4670 ** [SELECT] statement.
4671 ** ^The name of the database or table or column can be returned as
4672 ** either a UTF-8 or UTF-16 string.  ^The _database_ routines return
4673 ** the database name, the _table_ routines return the table name, and
4674 ** the origin_ routines return the column name.
4675 ** ^The returned string is valid until the [prepared statement] is destroyed
4676 ** using [sqlite3_finalize()] or until the statement is automatically
4677 ** reprepared by the first call to [sqlite3_step()] for a particular run
4678 ** or until the same information is requested
4679 ** again in a different encoding.
4680 **
4681 ** ^The names returned are the original un-aliased names of the
4682 ** database, table, and column.
4683 **
4684 ** ^The first argument to these interfaces is a [prepared statement].
4685 ** ^These functions return information about the Nth result column returned by
4686 ** the statement, where N is the second function argument.
4687 ** ^The left-most column is column 0 for these routines.
4688 **
4689 ** ^If the Nth column returned by the statement is an expression or
4690 ** subquery and is not a column value, then all of these functions return
4691 ** NULL.  ^These routines might also return NULL if a memory allocation error
4692 ** occurs.  ^Otherwise, they return the name of the attached database, table,
4693 ** or column that query result column was extracted from.
4694 **
4695 ** ^As with all other SQLite APIs, those whose names end with "16" return
4696 ** UTF-16 encoded strings and the other functions return UTF-8.
4697 **
4698 ** ^These APIs are only available if the library was compiled with the
4699 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
4700 **
4701 ** If two or more threads call one or more
4702 ** [sqlite3_column_database_name | column metadata interfaces]
4703 ** for the same [prepared statement] and result column
4704 ** at the same time then the results are undefined.
4705 */
4706 SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int);
4707 SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
4708 SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int);
4709 SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
4710 SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
4711 SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
4712 
4713 /*
4714 ** CAPI3REF: Declared Datatype Of A Query Result
4715 ** METHOD: sqlite3_stmt
4716 **
4717 ** ^(The first parameter is a [prepared statement].
4718 ** If this statement is a [SELECT] statement and the Nth column of the
4719 ** returned result set of that [SELECT] is a table column (not an
4720 ** expression or subquery) then the declared type of the table
4721 ** column is returned.)^  ^If the Nth column of the result set is an
4722 ** expression or subquery, then a NULL pointer is returned.
4723 ** ^The returned string is always UTF-8 encoded.
4724 **
4725 ** ^(For example, given the database schema:
4726 **
4727 ** CREATE TABLE t1(c1 VARIANT);
4728 **
4729 ** and the following statement to be compiled:
4730 **
4731 ** SELECT c1 + 1, c1 FROM t1;
4732 **
4733 ** this routine would return the string "VARIANT" for the second result
4734 ** column (i==1), and a NULL pointer for the first result column (i==0).)^
4735 **
4736 ** ^SQLite uses dynamic run-time typing.  ^So just because a column
4737 ** is declared to contain a particular type does not mean that the
4738 ** data stored in that column is of the declared type.  SQLite is
4739 ** strongly typed, but the typing is dynamic not static.  ^Type
4740 ** is associated with individual values, not with the containers
4741 ** used to hold those values.
4742 */
4743 SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int);
4744 SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
4745 
4746 /*
4747 ** CAPI3REF: Evaluate An SQL Statement
4748 ** METHOD: sqlite3_stmt
4749 **
4750 ** After a [prepared statement] has been prepared using any of
4751 ** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()],
4752 ** or [sqlite3_prepare16_v3()] or one of the legacy
4753 ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
4754 ** must be called one or more times to evaluate the statement.
4755 **
4756 ** The details of the behavior of the sqlite3_step() interface depend
4757 ** on whether the statement was prepared using the newer "vX" interfaces
4758 ** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()],
4759 ** [sqlite3_prepare16_v2()] or the older legacy
4760 ** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()].  The use of the
4761 ** new "vX" interface is recommended for new applications but the legacy
4762 ** interface will continue to be supported.
4763 **
4764 ** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
4765 ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
4766 ** ^With the "v2" interface, any of the other [result codes] or
4767 ** [extended result codes] might be returned as well.
4768 **
4769 ** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
4770 ** database locks it needs to do its job.  ^If the statement is a [COMMIT]
4771 ** or occurs outside of an explicit transaction, then you can retry the
4772 ** statement.  If the statement is not a [COMMIT] and occurs within an
4773 ** explicit transaction then you should rollback the transaction before
4774 ** continuing.
4775 **
4776 ** ^[SQLITE_DONE] means that the statement has finished executing
4777 ** successfully.  sqlite3_step() should not be called again on this virtual
4778 ** machine without first calling [sqlite3_reset()] to reset the virtual
4779 ** machine back to its initial state.
4780 **
4781 ** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
4782 ** is returned each time a new row of data is ready for processing by the
4783 ** caller. The values may be accessed using the [column access functions].
4784 ** sqlite3_step() is called again to retrieve the next row of data.
4785 **
4786 ** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
4787 ** violation) has occurred.  sqlite3_step() should not be called again on
4788 ** the VM. More information may be found by calling [sqlite3_errmsg()].
4789 ** ^With the legacy interface, a more specific error code (for example,
4790 ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
4791 ** can be obtained by calling [sqlite3_reset()] on the
4792 ** [prepared statement].  ^In the "v2" interface,
4793 ** the more specific error code is returned directly by sqlite3_step().
4794 **
4795 ** [SQLITE_MISUSE] means that the this routine was called inappropriately.
4796 ** Perhaps it was called on a [prepared statement] that has
4797 ** already been [sqlite3_finalize | finalized] or on one that had
4798 ** previously returned [SQLITE_ERROR] or [SQLITE_DONE].  Or it could
4799 ** be the case that the same database connection is being used by two or
4800 ** more threads at the same moment in time.
4801 **
4802 ** For all versions of SQLite up to and including 3.6.23.1, a call to
4803 ** [sqlite3_reset()] was required after sqlite3_step() returned anything
4804 ** other than [SQLITE_ROW] before any subsequent invocation of
4805 ** sqlite3_step().  Failure to reset the prepared statement using
4806 ** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
4807 ** sqlite3_step().  But after [version 3.6.23.1] ([dateof:3.6.23.1],
4808 ** sqlite3_step() began
4809 ** calling [sqlite3_reset()] automatically in this circumstance rather
4810 ** than returning [SQLITE_MISUSE].  This is not considered a compatibility
4811 ** break because any application that ever receives an SQLITE_MISUSE error
4812 ** is broken by definition.  The [SQLITE_OMIT_AUTORESET] compile-time option
4813 ** can be used to restore the legacy behavior.
4814 **
4815 ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
4816 ** API always returns a generic error code, [SQLITE_ERROR], following any
4817 ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE].  You must call
4818 ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
4819 ** specific [error codes] that better describes the error.
4820 ** We admit that this is a goofy design.  The problem has been fixed
4821 ** with the "v2" interface.  If you prepare all of your SQL statements
4822 ** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()]
4823 ** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead
4824 ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
4825 ** then the more specific [error codes] are returned directly
4826 ** by sqlite3_step().  The use of the "vX" interfaces is recommended.
4827 */
4828 SQLITE_API int sqlite3_step(sqlite3_stmt*);
4829 
4830 /*
4831 ** CAPI3REF: Number of columns in a result set
4832 ** METHOD: sqlite3_stmt
4833 **
4834 ** ^The sqlite3_data_count(P) interface returns the number of columns in the
4835 ** current row of the result set of [prepared statement] P.
4836 ** ^If prepared statement P does not have results ready to return
4837 ** (via calls to the [sqlite3_column_int | sqlite3_column()] family of
4838 ** interfaces) then sqlite3_data_count(P) returns 0.
4839 ** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
4840 ** ^The sqlite3_data_count(P) routine returns 0 if the previous call to
4841 ** [sqlite3_step](P) returned [SQLITE_DONE].  ^The sqlite3_data_count(P)
4842 ** will return non-zero if previous call to [sqlite3_step](P) returned
4843 ** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum]
4844 ** where it always returns zero since each step of that multi-step
4845 ** pragma returns 0 columns of data.
4846 **
4847 ** See also: [sqlite3_column_count()]
4848 */
4849 SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
4850 
4851 /*
4852 ** CAPI3REF: Fundamental Datatypes
4853 ** KEYWORDS: SQLITE_TEXT
4854 **
4855 ** ^(Every value in SQLite has one of five fundamental datatypes:
4856 **
4857 ** <ul>
4858 ** <li> 64-bit signed integer
4859 ** <li> 64-bit IEEE floating point number
4860 ** <li> string
4861 ** <li> BLOB
4862 ** <li> NULL
4863 ** </ul>)^
4864 **
4865 ** These constants are codes for each of those types.
4866 **
4867 ** Note that the SQLITE_TEXT constant was also used in SQLite version 2
4868 ** for a completely different meaning.  Software that links against both
4869 ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
4870 ** SQLITE_TEXT.
4871 */
4872 #define SQLITE_INTEGER  1
4873 #define SQLITE_FLOAT    2
4874 #define SQLITE_BLOB     4
4875 #define SQLITE_NULL     5
4876 #ifdef SQLITE_TEXT
4877 # undef SQLITE_TEXT
4878 #else
4879 # define SQLITE_TEXT     3
4880 #endif
4881 #define SQLITE3_TEXT     3
4882 
4883 /*
4884 ** CAPI3REF: Result Values From A Query
4885 ** KEYWORDS: {column access functions}
4886 ** METHOD: sqlite3_stmt
4887 **
4888 ** <b>Summary:</b>
4889 ** <blockquote><table border=0 cellpadding=0 cellspacing=0>
4890 ** <tr><td><b>sqlite3_column_blob</b><td>&rarr;<td>BLOB result
4891 ** <tr><td><b>sqlite3_column_double</b><td>&rarr;<td>REAL result
4892 ** <tr><td><b>sqlite3_column_int</b><td>&rarr;<td>32-bit INTEGER result
4893 ** <tr><td><b>sqlite3_column_int64</b><td>&rarr;<td>64-bit INTEGER result
4894 ** <tr><td><b>sqlite3_column_text</b><td>&rarr;<td>UTF-8 TEXT result
4895 ** <tr><td><b>sqlite3_column_text16</b><td>&rarr;<td>UTF-16 TEXT result
4896 ** <tr><td><b>sqlite3_column_value</b><td>&rarr;<td>The result as an
4897 ** [sqlite3_value|unprotected sqlite3_value] object.
4898 ** <tr><td>&nbsp;<td>&nbsp;<td>&nbsp;
4899 ** <tr><td><b>sqlite3_column_bytes</b><td>&rarr;<td>Size of a BLOB
4900 ** or a UTF-8 TEXT result in bytes
4901 ** <tr><td><b>sqlite3_column_bytes16&nbsp;&nbsp;</b>
4902 ** <td>&rarr;&nbsp;&nbsp;<td>Size of UTF-16
4903 ** TEXT in bytes
4904 ** <tr><td><b>sqlite3_column_type</b><td>&rarr;<td>Default
4905 ** datatype of the result
4906 ** </table></blockquote>
4907 **
4908 ** <b>Details:</b>
4909 **
4910 ** ^These routines return information about a single column of the current
4911 ** result row of a query.  ^In every case the first argument is a pointer
4912 ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
4913 ** that was returned from [sqlite3_prepare_v2()] or one of its variants)
4914 ** and the second argument is the index of the column for which information
4915 ** should be returned. ^The leftmost column of the result set has the index 0.
4916 ** ^The number of columns in the result can be determined using
4917 ** [sqlite3_column_count()].
4918 **
4919 ** If the SQL statement does not currently point to a valid row, or if the
4920 ** column index is out of range, the result is undefined.
4921 ** These routines may only be called when the most recent call to
4922 ** [sqlite3_step()] has returned [SQLITE_ROW] and neither
4923 ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
4924 ** If any of these routines are called after [sqlite3_reset()] or
4925 ** [sqlite3_finalize()] or after [sqlite3_step()] has returned
4926 ** something other than [SQLITE_ROW], the results are undefined.
4927 ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
4928 ** are called from a different thread while any of these routines
4929 ** are pending, then the results are undefined.
4930 **
4931 ** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16)
4932 ** each return the value of a result column in a specific data format.  If
4933 ** the result column is not initially in the requested format (for example,
4934 ** if the query returns an integer but the sqlite3_column_text() interface
4935 ** is used to extract the value) then an automatic type conversion is performed.
4936 **
4937 ** ^The sqlite3_column_type() routine returns the
4938 ** [SQLITE_INTEGER | datatype code] for the initial data type
4939 ** of the result column.  ^The returned value is one of [SQLITE_INTEGER],
4940 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].
4941 ** The return value of sqlite3_column_type() can be used to decide which
4942 ** of the first six interface should be used to extract the column value.
4943 ** The value returned by sqlite3_column_type() is only meaningful if no
4944 ** automatic type conversions have occurred for the value in question.
4945 ** After a type conversion, the result of calling sqlite3_column_type()
4946 ** is undefined, though harmless.  Future
4947 ** versions of SQLite may change the behavior of sqlite3_column_type()
4948 ** following a type conversion.
4949 **
4950 ** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes()
4951 ** or sqlite3_column_bytes16() interfaces can be used to determine the size
4952 ** of that BLOB or string.
4953 **
4954 ** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
4955 ** routine returns the number of bytes in that BLOB or string.
4956 ** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
4957 ** the string to UTF-8 and then returns the number of bytes.
4958 ** ^If the result is a numeric value then sqlite3_column_bytes() uses
4959 ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
4960 ** the number of bytes in that string.
4961 ** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
4962 **
4963 ** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
4964 ** routine returns the number of bytes in that BLOB or string.
4965 ** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
4966 ** the string to UTF-16 and then returns the number of bytes.
4967 ** ^If the result is a numeric value then sqlite3_column_bytes16() uses
4968 ** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
4969 ** the number of bytes in that string.
4970 ** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
4971 **
4972 ** ^The values returned by [sqlite3_column_bytes()] and
4973 ** [sqlite3_column_bytes16()] do not include the zero terminators at the end
4974 ** of the string.  ^For clarity: the values returned by
4975 ** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
4976 ** bytes in the string, not the number of characters.
4977 **
4978 ** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
4979 ** even empty strings, are always zero-terminated.  ^The return
4980 ** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
4981 **
4982 ** ^Strings returned by sqlite3_column_text16() always have the endianness
4983 ** which is native to the platform, regardless of the text encoding set
4984 ** for the database.
4985 **
4986 ** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an
4987 ** [unprotected sqlite3_value] object.  In a multithreaded environment,
4988 ** an unprotected sqlite3_value object may only be used safely with
4989 ** [sqlite3_bind_value()] and [sqlite3_result_value()].
4990 ** If the [unprotected sqlite3_value] object returned by
4991 ** [sqlite3_column_value()] is used in any other way, including calls
4992 ** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
4993 ** or [sqlite3_value_bytes()], the behavior is not threadsafe.
4994 ** Hence, the sqlite3_column_value() interface
4995 ** is normally only useful within the implementation of
4996 ** [application-defined SQL functions] or [virtual tables], not within
4997 ** top-level application code.
4998 **
4999 ** These routines may attempt to convert the datatype of the result.
5000 ** ^For example, if the internal representation is FLOAT and a text result
5001 ** is requested, [sqlite3_snprintf()] is used internally to perform the
5002 ** conversion automatically.  ^(The following table details the conversions
5003 ** that are applied:
5004 **
5005 ** <blockquote>
5006 ** <table border="1">
5007 ** <tr><th> Internal<br>Type <th> Requested<br>Type <th>  Conversion
5008 **
5009 ** <tr><td>  NULL    <td> INTEGER   <td> Result is 0
5010 ** <tr><td>  NULL    <td>  FLOAT    <td> Result is 0.0
5011 ** <tr><td>  NULL    <td>   TEXT    <td> Result is a NULL pointer
5012 ** <tr><td>  NULL    <td>   BLOB    <td> Result is a NULL pointer
5013 ** <tr><td> INTEGER  <td>  FLOAT    <td> Convert from integer to float
5014 ** <tr><td> INTEGER  <td>   TEXT    <td> ASCII rendering of the integer
5015 ** <tr><td> INTEGER  <td>   BLOB    <td> Same as INTEGER->TEXT
5016 ** <tr><td>  FLOAT   <td> INTEGER   <td> [CAST] to INTEGER
5017 ** <tr><td>  FLOAT   <td>   TEXT    <td> ASCII rendering of the float
5018 ** <tr><td>  FLOAT   <td>   BLOB    <td> [CAST] to BLOB
5019 ** <tr><td>  TEXT    <td> INTEGER   <td> [CAST] to INTEGER
5020 ** <tr><td>  TEXT    <td>  FLOAT    <td> [CAST] to REAL
5021 ** <tr><td>  TEXT    <td>   BLOB    <td> No change
5022 ** <tr><td>  BLOB    <td> INTEGER   <td> [CAST] to INTEGER
5023 ** <tr><td>  BLOB    <td>  FLOAT    <td> [CAST] to REAL
5024 ** <tr><td>  BLOB    <td>   TEXT    <td> [CAST] to TEXT, ensure zero terminator
5025 ** </table>
5026 ** </blockquote>)^
5027 **
5028 ** Note that when type conversions occur, pointers returned by prior
5029 ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
5030 ** sqlite3_column_text16() may be invalidated.
5031 ** Type conversions and pointer invalidations might occur
5032 ** in the following cases:
5033 **
5034 ** <ul>
5035 ** <li> The initial content is a BLOB and sqlite3_column_text() or
5036 **      sqlite3_column_text16() is called.  A zero-terminator might
5037 **      need to be added to the string.</li>
5038 ** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
5039 **      sqlite3_column_text16() is called.  The content must be converted
5040 **      to UTF-16.</li>
5041 ** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
5042 **      sqlite3_column_text() is called.  The content must be converted
5043 **      to UTF-8.</li>
5044 ** </ul>
5045 **
5046 ** ^Conversions between UTF-16be and UTF-16le are always done in place and do
5047 ** not invalidate a prior pointer, though of course the content of the buffer
5048 ** that the prior pointer references will have been modified.  Other kinds
5049 ** of conversion are done in place when it is possible, but sometimes they
5050 ** are not possible and in those cases prior pointers are invalidated.
5051 **
5052 ** The safest policy is to invoke these routines
5053 ** in one of the following ways:
5054 **
5055 ** <ul>
5056 **  <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
5057 **  <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
5058 **  <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
5059 ** </ul>
5060 **
5061 ** In other words, you should call sqlite3_column_text(),
5062 ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
5063 ** into the desired format, then invoke sqlite3_column_bytes() or
5064 ** sqlite3_column_bytes16() to find the size of the result.  Do not mix calls
5065 ** to sqlite3_column_text() or sqlite3_column_blob() with calls to
5066 ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
5067 ** with calls to sqlite3_column_bytes().
5068 **
5069 ** ^The pointers returned are valid until a type conversion occurs as
5070 ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
5071 ** [sqlite3_finalize()] is called.  ^The memory space used to hold strings
5072 ** and BLOBs is freed automatically.  Do not pass the pointers returned
5073 ** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
5074 ** [sqlite3_free()].
5075 **
5076 ** As long as the input parameters are correct, these routines will only
5077 ** fail if an out-of-memory error occurs during a format conversion.
5078 ** Only the following subset of interfaces are subject to out-of-memory
5079 ** errors:
5080 **
5081 ** <ul>
5082 ** <li> sqlite3_column_blob()
5083 ** <li> sqlite3_column_text()
5084 ** <li> sqlite3_column_text16()
5085 ** <li> sqlite3_column_bytes()
5086 ** <li> sqlite3_column_bytes16()
5087 ** </ul>
5088 **
5089 ** If an out-of-memory error occurs, then the return value from these
5090 ** routines is the same as if the column had contained an SQL NULL value.
5091 ** Valid SQL NULL returns can be distinguished from out-of-memory errors
5092 ** by invoking the [sqlite3_errcode()] immediately after the suspect
5093 ** return value is obtained and before any
5094 ** other SQLite interface is called on the same [database connection].
5095 */
5096 SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
5097 SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol);
5098 SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol);
5099 SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
5100 SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
5101 SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
5102 SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
5103 SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
5104 SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
5105 SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol);
5106 
5107 /*
5108 ** CAPI3REF: Destroy A Prepared Statement Object
5109 ** DESTRUCTOR: sqlite3_stmt
5110 **
5111 ** ^The sqlite3_finalize() function is called to delete a [prepared statement].
5112 ** ^If the most recent evaluation of the statement encountered no errors
5113 ** or if the statement is never been evaluated, then sqlite3_finalize() returns
5114 ** SQLITE_OK.  ^If the most recent evaluation of statement S failed, then
5115 ** sqlite3_finalize(S) returns the appropriate [error code] or
5116 ** [extended error code].
5117 **
5118 ** ^The sqlite3_finalize(S) routine can be called at any point during
5119 ** the life cycle of [prepared statement] S:
5120 ** before statement S is ever evaluated, after
5121 ** one or more calls to [sqlite3_reset()], or after any call
5122 ** to [sqlite3_step()] regardless of whether or not the statement has
5123 ** completed execution.
5124 **
5125 ** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
5126 **
5127 ** The application must finalize every [prepared statement] in order to avoid
5128 ** resource leaks.  It is a grievous error for the application to try to use
5129 ** a prepared statement after it has been finalized.  Any use of a prepared
5130 ** statement after it has been finalized can result in undefined and
5131 ** undesirable behavior such as segfaults and heap corruption.
5132 */
5133 SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt);
5134 
5135 /*
5136 ** CAPI3REF: Reset A Prepared Statement Object
5137 ** METHOD: sqlite3_stmt
5138 **
5139 ** The sqlite3_reset() function is called to reset a [prepared statement]
5140 ** object back to its initial state, ready to be re-executed.
5141 ** ^Any SQL statement variables that had values bound to them using
5142 ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
5143 ** Use [sqlite3_clear_bindings()] to reset the bindings.
5144 **
5145 ** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
5146 ** back to the beginning of its program.
5147 **
5148 ** ^If the most recent call to [sqlite3_step(S)] for the
5149 ** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
5150 ** or if [sqlite3_step(S)] has never before been called on S,
5151 ** then [sqlite3_reset(S)] returns [SQLITE_OK].
5152 **
5153 ** ^If the most recent call to [sqlite3_step(S)] for the
5154 ** [prepared statement] S indicated an error, then
5155 ** [sqlite3_reset(S)] returns an appropriate [error code].
5156 **
5157 ** ^The [sqlite3_reset(S)] interface does not change the values
5158 ** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
5159 */
5160 SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt);
5161 
5162 /*
5163 ** CAPI3REF: Create Or Redefine SQL Functions
5164 ** KEYWORDS: {function creation routines}
5165 ** METHOD: sqlite3
5166 **
5167 ** ^These functions (collectively known as "function creation routines")
5168 ** are used to add SQL functions or aggregates or to redefine the behavior
5169 ** of existing SQL functions or aggregates. The only differences between
5170 ** the three "sqlite3_create_function*" routines are the text encoding
5171 ** expected for the second parameter (the name of the function being
5172 ** created) and the presence or absence of a destructor callback for
5173 ** the application data pointer. Function sqlite3_create_window_function()
5174 ** is similar, but allows the user to supply the extra callback functions
5175 ** needed by [aggregate window functions].
5176 **
5177 ** ^The first parameter is the [database connection] to which the SQL
5178 ** function is to be added.  ^If an application uses more than one database
5179 ** connection then application-defined SQL functions must be added
5180 ** to each database connection separately.
5181 **
5182 ** ^The second parameter is the name of the SQL function to be created or
5183 ** redefined.  ^The length of the name is limited to 255 bytes in a UTF-8
5184 ** representation, exclusive of the zero-terminator.  ^Note that the name
5185 ** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
5186 ** ^Any attempt to create a function with a longer name
5187 ** will result in [SQLITE_MISUSE] being returned.
5188 **
5189 ** ^The third parameter (nArg)
5190 ** is the number of arguments that the SQL function or
5191 ** aggregate takes. ^If this parameter is -1, then the SQL function or
5192 ** aggregate may take any number of arguments between 0 and the limit
5193 ** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]).  If the third
5194 ** parameter is less than -1 or greater than 127 then the behavior is
5195 ** undefined.
5196 **
5197 ** ^The fourth parameter, eTextRep, specifies what
5198 ** [SQLITE_UTF8 | text encoding] this SQL function prefers for
5199 ** its parameters.  The application should set this parameter to
5200 ** [SQLITE_UTF16LE] if the function implementation invokes
5201 ** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the
5202 ** implementation invokes [sqlite3_value_text16be()] on an input, or
5203 ** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8]
5204 ** otherwise.  ^The same SQL function may be registered multiple times using
5205 ** different preferred text encodings, with different implementations for
5206 ** each encoding.
5207 ** ^When multiple implementations of the same function are available, SQLite
5208 ** will pick the one that involves the least amount of data conversion.
5209 **
5210 ** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC]
5211 ** to signal that the function will always return the same result given
5212 ** the same inputs within a single SQL statement.  Most SQL functions are
5213 ** deterministic.  The built-in [random()] SQL function is an example of a
5214 ** function that is not deterministic.  The SQLite query planner is able to
5215 ** perform additional optimizations on deterministic functions, so use
5216 ** of the [SQLITE_DETERMINISTIC] flag is recommended where possible.
5217 **
5218 ** ^The fourth parameter may also optionally include the [SQLITE_DIRECTONLY]
5219 ** flag, which if present prevents the function from being invoked from
5220 ** within VIEWs, TRIGGERs, CHECK constraints, generated column expressions,
5221 ** index expressions, or the WHERE clause of partial indexes.
5222 **
5223 ** For best security, the [SQLITE_DIRECTONLY] flag is recommended for
5224 ** all application-defined SQL functions that do not need to be
5225 ** used inside of triggers, view, CHECK constraints, or other elements of
5226 ** the database schema.  This flags is especially recommended for SQL
5227 ** functions that have side effects or reveal internal application state.
5228 ** Without this flag, an attacker might be able to modify the schema of
5229 ** a database file to include invocations of the function with parameters
5230 ** chosen by the attacker, which the application will then execute when
5231 ** the database file is opened and read.
5232 **
5233 ** ^(The fifth parameter is an arbitrary pointer.  The implementation of the
5234 ** function can gain access to this pointer using [sqlite3_user_data()].)^
5235 **
5236 ** ^The sixth, seventh and eighth parameters passed to the three
5237 ** "sqlite3_create_function*" functions, xFunc, xStep and xFinal, are
5238 ** pointers to C-language functions that implement the SQL function or
5239 ** aggregate. ^A scalar SQL function requires an implementation of the xFunc
5240 ** callback only; NULL pointers must be passed as the xStep and xFinal
5241 ** parameters. ^An aggregate SQL function requires an implementation of xStep
5242 ** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
5243 ** SQL function or aggregate, pass NULL pointers for all three function
5244 ** callbacks.
5245 **
5246 ** ^The sixth, seventh, eighth and ninth parameters (xStep, xFinal, xValue
5247 ** and xInverse) passed to sqlite3_create_window_function are pointers to
5248 ** C-language callbacks that implement the new function. xStep and xFinal
5249 ** must both be non-NULL. xValue and xInverse may either both be NULL, in
5250 ** which case a regular aggregate function is created, or must both be
5251 ** non-NULL, in which case the new function may be used as either an aggregate
5252 ** or aggregate window function. More details regarding the implementation
5253 ** of aggregate window functions are
5254 ** [user-defined window functions|available here].
5255 **
5256 ** ^(If the final parameter to sqlite3_create_function_v2() or
5257 ** sqlite3_create_window_function() is not NULL, then it is destructor for
5258 ** the application data pointer. The destructor is invoked when the function
5259 ** is deleted, either by being overloaded or when the database connection
5260 ** closes.)^ ^The destructor is also invoked if the call to
5261 ** sqlite3_create_function_v2() fails.  ^When the destructor callback is
5262 ** invoked, it is passed a single argument which is a copy of the application
5263 ** data pointer which was the fifth parameter to sqlite3_create_function_v2().
5264 **
5265 ** ^It is permitted to register multiple implementations of the same
5266 ** functions with the same name but with either differing numbers of
5267 ** arguments or differing preferred text encodings.  ^SQLite will use
5268 ** the implementation that most closely matches the way in which the
5269 ** SQL function is used.  ^A function implementation with a non-negative
5270 ** nArg parameter is a better match than a function implementation with
5271 ** a negative nArg.  ^A function where the preferred text encoding
5272 ** matches the database encoding is a better
5273 ** match than a function where the encoding is different.
5274 ** ^A function where the encoding difference is between UTF16le and UTF16be
5275 ** is a closer match than a function where the encoding difference is
5276 ** between UTF8 and UTF16.
5277 **
5278 ** ^Built-in functions may be overloaded by new application-defined functions.
5279 **
5280 ** ^An application-defined function is permitted to call other
5281 ** SQLite interfaces.  However, such calls must not
5282 ** close the database connection nor finalize or reset the prepared
5283 ** statement in which the function is running.
5284 */
5285 SQLITE_API int sqlite3_create_function(
5286   sqlite3 *db,
5287   const char *zFunctionName,
5288   int nArg,
5289   int eTextRep,
5290   void *pApp,
5291   void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
5292   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
5293   void (*xFinal)(sqlite3_context*)
5294 );
5295 SQLITE_API int sqlite3_create_function16(
5296   sqlite3 *db,
5297   const void *zFunctionName,
5298   int nArg,
5299   int eTextRep,
5300   void *pApp,
5301   void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
5302   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
5303   void (*xFinal)(sqlite3_context*)
5304 );
5305 SQLITE_API int sqlite3_create_function_v2(
5306   sqlite3 *db,
5307   const char *zFunctionName,
5308   int nArg,
5309   int eTextRep,
5310   void *pApp,
5311   void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
5312   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
5313   void (*xFinal)(sqlite3_context*),
5314   void(*xDestroy)(void*)
5315 );
5316 SQLITE_API int sqlite3_create_window_function(
5317   sqlite3 *db,
5318   const char *zFunctionName,
5319   int nArg,
5320   int eTextRep,
5321   void *pApp,
5322   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
5323   void (*xFinal)(sqlite3_context*),
5324   void (*xValue)(sqlite3_context*),
5325   void (*xInverse)(sqlite3_context*,int,sqlite3_value**),
5326   void(*xDestroy)(void*)
5327 );
5328 
5329 /*
5330 ** CAPI3REF: Text Encodings
5331 **
5332 ** These constant define integer codes that represent the various
5333 ** text encodings supported by SQLite.
5334 */
5335 #define SQLITE_UTF8           1    /* IMP: R-37514-35566 */
5336 #define SQLITE_UTF16LE        2    /* IMP: R-03371-37637 */
5337 #define SQLITE_UTF16BE        3    /* IMP: R-51971-34154 */
5338 #define SQLITE_UTF16          4    /* Use native byte order */
5339 #define SQLITE_ANY            5    /* Deprecated */
5340 #define SQLITE_UTF16_ALIGNED  8    /* sqlite3_create_collation only */
5341 
5342 /*
5343 ** CAPI3REF: Function Flags
5344 **
5345 ** These constants may be ORed together with the
5346 ** [SQLITE_UTF8 | preferred text encoding] as the fourth argument
5347 ** to [sqlite3_create_function()], [sqlite3_create_function16()], or
5348 ** [sqlite3_create_function_v2()].
5349 **
5350 ** <dl>
5351 ** [[SQLITE_DETERMINISTIC]] <dt>SQLITE_DETERMINISTIC</dt><dd>
5352 ** The SQLITE_DETERMINISTIC flag means that the new function always gives
5353 ** the same output when the input parameters are the same.
5354 ** The [abs|abs() function] is deterministic, for example, but
5355 ** [randomblob|randomblob()] is not.  Functions must
5356 ** be deterministic in order to be used in certain contexts such as
5357 ** with the WHERE clause of [partial indexes] or in [generated columns].
5358 ** SQLite might also optimize deterministic functions by factoring them
5359 ** out of inner loops.
5360 ** </dd>
5361 **
5362 ** [[SQLITE_DIRECTONLY]] <dt>SQLITE_DIRECTONLY</dt><dd>
5363 ** The SQLITE_DIRECTONLY flag means that the function may only be invoked
5364 ** from top-level SQL, and cannot be used in VIEWs or TRIGGERs nor in
5365 ** schema structures such as [CHECK constraints], [DEFAULT clauses],
5366 ** [expression indexes], [partial indexes], or [generated columns].
5367 ** The SQLITE_DIRECTONLY flags is a security feature which is recommended
5368 ** for all [application-defined SQL functions], and especially for functions
5369 ** that have side-effects or that could potentially leak sensitive
5370 ** information.
5371 ** </dd>
5372 **
5373 ** [[SQLITE_INNOCUOUS]] <dt>SQLITE_INNOCUOUS</dt><dd>
5374 ** The SQLITE_INNOCUOUS flag means that the function is unlikely
5375 ** to cause problems even if misused.  An innocuous function should have
5376 ** no side effects and should not depend on any values other than its
5377 ** input parameters. The [abs|abs() function] is an example of an
5378 ** innocuous function.
5379 ** The [load_extension() SQL function] is not innocuous because of its
5380 ** side effects.
5381 ** <p> SQLITE_INNOCUOUS is similar to SQLITE_DETERMINISTIC, but is not
5382 ** exactly the same.  The [random|random() function] is an example of a
5383 ** function that is innocuous but not deterministic.
5384 ** <p>Some heightened security settings
5385 ** ([SQLITE_DBCONFIG_TRUSTED_SCHEMA] and [PRAGMA trusted_schema=OFF])
5386 ** disable the use of SQL functions inside views and triggers and in
5387 ** schema structures such as [CHECK constraints], [DEFAULT clauses],
5388 ** [expression indexes], [partial indexes], and [generated columns] unless
5389 ** the function is tagged with SQLITE_INNOCUOUS.  Most built-in functions
5390 ** are innocuous.  Developers are advised to avoid using the
5391 ** SQLITE_INNOCUOUS flag for application-defined functions unless the
5392 ** function has been carefully audited and found to be free of potentially
5393 ** security-adverse side-effects and information-leaks.
5394 ** </dd>
5395 **
5396 ** [[SQLITE_SUBTYPE]] <dt>SQLITE_SUBTYPE</dt><dd>
5397 ** The SQLITE_SUBTYPE flag indicates to SQLite that a function may call
5398 ** [sqlite3_value_subtype()] to inspect the sub-types of its arguments.
5399 ** Specifying this flag makes no difference for scalar or aggregate user
5400 ** functions. However, if it is not specified for a user-defined window
5401 ** function, then any sub-types belonging to arguments passed to the window
5402 ** function may be discarded before the window function is called (i.e.
5403 ** sqlite3_value_subtype() will always return 0).
5404 ** </dd>
5405 ** </dl>
5406 */
5407 #define SQLITE_DETERMINISTIC    0x000000800
5408 #define SQLITE_DIRECTONLY       0x000080000
5409 #define SQLITE_SUBTYPE          0x000100000
5410 #define SQLITE_INNOCUOUS        0x000200000
5411 
5412 /*
5413 ** CAPI3REF: Deprecated Functions
5414 ** DEPRECATED
5415 **
5416 ** These functions are [deprecated].  In order to maintain
5417 ** backwards compatibility with older code, these functions continue
5418 ** to be supported.  However, new applications should avoid
5419 ** the use of these functions.  To encourage programmers to avoid
5420 ** these functions, we will not explain what they do.
5421 */
5422 #ifndef SQLITE_OMIT_DEPRECATED
5423 SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
5424 SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
5425 SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
5426 SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void);
5427 SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
5428 SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),
5429                       void*,sqlite3_int64);
5430 #endif
5431 
5432 /*
5433 ** CAPI3REF: Obtaining SQL Values
5434 ** METHOD: sqlite3_value
5435 **
5436 ** <b>Summary:</b>
5437 ** <blockquote><table border=0 cellpadding=0 cellspacing=0>
5438 ** <tr><td><b>sqlite3_value_blob</b><td>&rarr;<td>BLOB value
5439 ** <tr><td><b>sqlite3_value_double</b><td>&rarr;<td>REAL value
5440 ** <tr><td><b>sqlite3_value_int</b><td>&rarr;<td>32-bit INTEGER value
5441 ** <tr><td><b>sqlite3_value_int64</b><td>&rarr;<td>64-bit INTEGER value
5442 ** <tr><td><b>sqlite3_value_pointer</b><td>&rarr;<td>Pointer value
5443 ** <tr><td><b>sqlite3_value_text</b><td>&rarr;<td>UTF-8 TEXT value
5444 ** <tr><td><b>sqlite3_value_text16</b><td>&rarr;<td>UTF-16 TEXT value in
5445 ** the native byteorder
5446 ** <tr><td><b>sqlite3_value_text16be</b><td>&rarr;<td>UTF-16be TEXT value
5447 ** <tr><td><b>sqlite3_value_text16le</b><td>&rarr;<td>UTF-16le TEXT value
5448 ** <tr><td>&nbsp;<td>&nbsp;<td>&nbsp;
5449 ** <tr><td><b>sqlite3_value_bytes</b><td>&rarr;<td>Size of a BLOB
5450 ** or a UTF-8 TEXT in bytes
5451 ** <tr><td><b>sqlite3_value_bytes16&nbsp;&nbsp;</b>
5452 ** <td>&rarr;&nbsp;&nbsp;<td>Size of UTF-16
5453 ** TEXT in bytes
5454 ** <tr><td><b>sqlite3_value_type</b><td>&rarr;<td>Default
5455 ** datatype of the value
5456 ** <tr><td><b>sqlite3_value_numeric_type&nbsp;&nbsp;</b>
5457 ** <td>&rarr;&nbsp;&nbsp;<td>Best numeric datatype of the value
5458 ** <tr><td><b>sqlite3_value_nochange&nbsp;&nbsp;</b>
5459 ** <td>&rarr;&nbsp;&nbsp;<td>True if the column is unchanged in an UPDATE
5460 ** against a virtual table.
5461 ** <tr><td><b>sqlite3_value_frombind&nbsp;&nbsp;</b>
5462 ** <td>&rarr;&nbsp;&nbsp;<td>True if value originated from a [bound parameter]
5463 ** </table></blockquote>
5464 **
5465 ** <b>Details:</b>
5466 **
5467 ** These routines extract type, size, and content information from
5468 ** [protected sqlite3_value] objects.  Protected sqlite3_value objects
5469 ** are used to pass parameter information into the functions that
5470 ** implement [application-defined SQL functions] and [virtual tables].
5471 **
5472 ** These routines work only with [protected sqlite3_value] objects.
5473 ** Any attempt to use these routines on an [unprotected sqlite3_value]
5474 ** is not threadsafe.
5475 **
5476 ** ^These routines work just like the corresponding [column access functions]
5477 ** except that these routines take a single [protected sqlite3_value] object
5478 ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
5479 **
5480 ** ^The sqlite3_value_text16() interface extracts a UTF-16 string
5481 ** in the native byte-order of the host machine.  ^The
5482 ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
5483 ** extract UTF-16 strings as big-endian and little-endian respectively.
5484 **
5485 ** ^If [sqlite3_value] object V was initialized
5486 ** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)]
5487 ** and if X and Y are strings that compare equal according to strcmp(X,Y),
5488 ** then sqlite3_value_pointer(V,Y) will return the pointer P.  ^Otherwise,
5489 ** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer()
5490 ** routine is part of the [pointer passing interface] added for SQLite 3.20.0.
5491 **
5492 ** ^(The sqlite3_value_type(V) interface returns the
5493 ** [SQLITE_INTEGER | datatype code] for the initial datatype of the
5494 ** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER],
5495 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^
5496 ** Other interfaces might change the datatype for an sqlite3_value object.
5497 ** For example, if the datatype is initially SQLITE_INTEGER and
5498 ** sqlite3_value_text(V) is called to extract a text value for that
5499 ** integer, then subsequent calls to sqlite3_value_type(V) might return
5500 ** SQLITE_TEXT.  Whether or not a persistent internal datatype conversion
5501 ** occurs is undefined and may change from one release of SQLite to the next.
5502 **
5503 ** ^(The sqlite3_value_numeric_type() interface attempts to apply
5504 ** numeric affinity to the value.  This means that an attempt is
5505 ** made to convert the value to an integer or floating point.  If
5506 ** such a conversion is possible without loss of information (in other
5507 ** words, if the value is a string that looks like a number)
5508 ** then the conversion is performed.  Otherwise no conversion occurs.
5509 ** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
5510 **
5511 ** ^Within the [xUpdate] method of a [virtual table], the
5512 ** sqlite3_value_nochange(X) interface returns true if and only if
5513 ** the column corresponding to X is unchanged by the UPDATE operation
5514 ** that the xUpdate method call was invoked to implement and if
5515 ** and the prior [xColumn] method call that was invoked to extracted
5516 ** the value for that column returned without setting a result (probably
5517 ** because it queried [sqlite3_vtab_nochange()] and found that the column
5518 ** was unchanging).  ^Within an [xUpdate] method, any value for which
5519 ** sqlite3_value_nochange(X) is true will in all other respects appear
5520 ** to be a NULL value.  If sqlite3_value_nochange(X) is invoked anywhere other
5521 ** than within an [xUpdate] method call for an UPDATE statement, then
5522 ** the return value is arbitrary and meaningless.
5523 **
5524 ** ^The sqlite3_value_frombind(X) interface returns non-zero if the
5525 ** value X originated from one of the [sqlite3_bind_int|sqlite3_bind()]
5526 ** interfaces.  ^If X comes from an SQL literal value, or a table column,
5527 ** or an expression, then sqlite3_value_frombind(X) returns zero.
5528 **
5529 ** Please pay particular attention to the fact that the pointer returned
5530 ** from [sqlite3_value_blob()], [sqlite3_value_text()], or
5531 ** [sqlite3_value_text16()] can be invalidated by a subsequent call to
5532 ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
5533 ** or [sqlite3_value_text16()].
5534 **
5535 ** These routines must be called from the same thread as
5536 ** the SQL function that supplied the [sqlite3_value*] parameters.
5537 **
5538 ** As long as the input parameter is correct, these routines can only
5539 ** fail if an out-of-memory error occurs during a format conversion.
5540 ** Only the following subset of interfaces are subject to out-of-memory
5541 ** errors:
5542 **
5543 ** <ul>
5544 ** <li> sqlite3_value_blob()
5545 ** <li> sqlite3_value_text()
5546 ** <li> sqlite3_value_text16()
5547 ** <li> sqlite3_value_text16le()
5548 ** <li> sqlite3_value_text16be()
5549 ** <li> sqlite3_value_bytes()
5550 ** <li> sqlite3_value_bytes16()
5551 ** </ul>
5552 **
5553 ** If an out-of-memory error occurs, then the return value from these
5554 ** routines is the same as if the column had contained an SQL NULL value.
5555 ** Valid SQL NULL returns can be distinguished from out-of-memory errors
5556 ** by invoking the [sqlite3_errcode()] immediately after the suspect
5557 ** return value is obtained and before any
5558 ** other SQLite interface is called on the same [database connection].
5559 */
5560 SQLITE_API const void *sqlite3_value_blob(sqlite3_value*);
5561 SQLITE_API double sqlite3_value_double(sqlite3_value*);
5562 SQLITE_API int sqlite3_value_int(sqlite3_value*);
5563 SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
5564 SQLITE_API void *sqlite3_value_pointer(sqlite3_value*, const char*);
5565 SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*);
5566 SQLITE_API const void *sqlite3_value_text16(sqlite3_value*);
5567 SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*);
5568 SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*);
5569 SQLITE_API int sqlite3_value_bytes(sqlite3_value*);
5570 SQLITE_API int sqlite3_value_bytes16(sqlite3_value*);
5571 SQLITE_API int sqlite3_value_type(sqlite3_value*);
5572 SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*);
5573 SQLITE_API int sqlite3_value_nochange(sqlite3_value*);
5574 SQLITE_API int sqlite3_value_frombind(sqlite3_value*);
5575 
5576 /*
5577 ** CAPI3REF: Finding The Subtype Of SQL Values
5578 ** METHOD: sqlite3_value
5579 **
5580 ** The sqlite3_value_subtype(V) function returns the subtype for
5581 ** an [application-defined SQL function] argument V.  The subtype
5582 ** information can be used to pass a limited amount of context from
5583 ** one SQL function to another.  Use the [sqlite3_result_subtype()]
5584 ** routine to set the subtype for the return value of an SQL function.
5585 */
5586 SQLITE_API unsigned int sqlite3_value_subtype(sqlite3_value*);
5587 
5588 /*
5589 ** CAPI3REF: Copy And Free SQL Values
5590 ** METHOD: sqlite3_value
5591 **
5592 ** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value]
5593 ** object D and returns a pointer to that copy.  ^The [sqlite3_value] returned
5594 ** is a [protected sqlite3_value] object even if the input is not.
5595 ** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a
5596 ** memory allocation fails. ^If V is a [pointer value], then the result
5597 ** of sqlite3_value_dup(V) is a NULL value.
5598 **
5599 ** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object
5600 ** previously obtained from [sqlite3_value_dup()].  ^If V is a NULL pointer
5601 ** then sqlite3_value_free(V) is a harmless no-op.
5602 */
5603 SQLITE_API sqlite3_value *sqlite3_value_dup(const sqlite3_value*);
5604 SQLITE_API void sqlite3_value_free(sqlite3_value*);
5605 
5606 /*
5607 ** CAPI3REF: Obtain Aggregate Function Context
5608 ** METHOD: sqlite3_context
5609 **
5610 ** Implementations of aggregate SQL functions use this
5611 ** routine to allocate memory for storing their state.
5612 **
5613 ** ^The first time the sqlite3_aggregate_context(C,N) routine is called
5614 ** for a particular aggregate function, SQLite allocates
5615 ** N bytes of memory, zeroes out that memory, and returns a pointer
5616 ** to the new memory. ^On second and subsequent calls to
5617 ** sqlite3_aggregate_context() for the same aggregate function instance,
5618 ** the same buffer is returned.  Sqlite3_aggregate_context() is normally
5619 ** called once for each invocation of the xStep callback and then one
5620 ** last time when the xFinal callback is invoked.  ^(When no rows match
5621 ** an aggregate query, the xStep() callback of the aggregate function
5622 ** implementation is never called and xFinal() is called exactly once.
5623 ** In those cases, sqlite3_aggregate_context() might be called for the
5624 ** first time from within xFinal().)^
5625 **
5626 ** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer
5627 ** when first called if N is less than or equal to zero or if a memory
5628 ** allocate error occurs.
5629 **
5630 ** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
5631 ** determined by the N parameter on first successful call.  Changing the
5632 ** value of N in any subsequent call to sqlite3_aggregate_context() within
5633 ** the same aggregate function instance will not resize the memory
5634 ** allocation.)^  Within the xFinal callback, it is customary to set
5635 ** N=0 in calls to sqlite3_aggregate_context(C,N) so that no
5636 ** pointless memory allocations occur.
5637 **
5638 ** ^SQLite automatically frees the memory allocated by
5639 ** sqlite3_aggregate_context() when the aggregate query concludes.
5640 **
5641 ** The first parameter must be a copy of the
5642 ** [sqlite3_context | SQL function context] that is the first parameter
5643 ** to the xStep or xFinal callback routine that implements the aggregate
5644 ** function.
5645 **
5646 ** This routine must be called from the same thread in which
5647 ** the aggregate SQL function is running.
5648 */
5649 SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
5650 
5651 /*
5652 ** CAPI3REF: User Data For Functions
5653 ** METHOD: sqlite3_context
5654 **
5655 ** ^The sqlite3_user_data() interface returns a copy of
5656 ** the pointer that was the pUserData parameter (the 5th parameter)
5657 ** of the [sqlite3_create_function()]
5658 ** and [sqlite3_create_function16()] routines that originally
5659 ** registered the application defined function.
5660 **
5661 ** This routine must be called from the same thread in which
5662 ** the application-defined function is running.
5663 */
5664 SQLITE_API void *sqlite3_user_data(sqlite3_context*);
5665 
5666 /*
5667 ** CAPI3REF: Database Connection For Functions
5668 ** METHOD: sqlite3_context
5669 **
5670 ** ^The sqlite3_context_db_handle() interface returns a copy of
5671 ** the pointer to the [database connection] (the 1st parameter)
5672 ** of the [sqlite3_create_function()]
5673 ** and [sqlite3_create_function16()] routines that originally
5674 ** registered the application defined function.
5675 */
5676 SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
5677 
5678 /*
5679 ** CAPI3REF: Function Auxiliary Data
5680 ** METHOD: sqlite3_context
5681 **
5682 ** These functions may be used by (non-aggregate) SQL functions to
5683 ** associate metadata with argument values. If the same value is passed to
5684 ** multiple invocations of the same SQL function during query execution, under
5685 ** some circumstances the associated metadata may be preserved.  An example
5686 ** of where this might be useful is in a regular-expression matching
5687 ** function. The compiled version of the regular expression can be stored as
5688 ** metadata associated with the pattern string.
5689 ** Then as long as the pattern string remains the same,
5690 ** the compiled regular expression can be reused on multiple
5691 ** invocations of the same function.
5692 **
5693 ** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the metadata
5694 ** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument
5695 ** value to the application-defined function.  ^N is zero for the left-most
5696 ** function argument.  ^If there is no metadata
5697 ** associated with the function argument, the sqlite3_get_auxdata(C,N) interface
5698 ** returns a NULL pointer.
5699 **
5700 ** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th
5701 ** argument of the application-defined function.  ^Subsequent
5702 ** calls to sqlite3_get_auxdata(C,N) return P from the most recent
5703 ** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or
5704 ** NULL if the metadata has been discarded.
5705 ** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL,
5706 ** SQLite will invoke the destructor function X with parameter P exactly
5707 ** once, when the metadata is discarded.
5708 ** SQLite is free to discard the metadata at any time, including: <ul>
5709 ** <li> ^(when the corresponding function parameter changes)^, or
5710 ** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the
5711 **      SQL statement)^, or
5712 ** <li> ^(when sqlite3_set_auxdata() is invoked again on the same
5713 **       parameter)^, or
5714 ** <li> ^(during the original sqlite3_set_auxdata() call when a memory
5715 **      allocation error occurs.)^ </ul>
5716 **
5717 ** Note the last bullet in particular.  The destructor X in
5718 ** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the
5719 ** sqlite3_set_auxdata() interface even returns.  Hence sqlite3_set_auxdata()
5720 ** should be called near the end of the function implementation and the
5721 ** function implementation should not make any use of P after
5722 ** sqlite3_set_auxdata() has been called.
5723 **
5724 ** ^(In practice, metadata is preserved between function calls for
5725 ** function parameters that are compile-time constants, including literal
5726 ** values and [parameters] and expressions composed from the same.)^
5727 **
5728 ** The value of the N parameter to these interfaces should be non-negative.
5729 ** Future enhancements may make use of negative N values to define new
5730 ** kinds of function caching behavior.
5731 **
5732 ** These routines must be called from the same thread in which
5733 ** the SQL function is running.
5734 */
5735 SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N);
5736 SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
5737 
5738 
5739 /*
5740 ** CAPI3REF: Constants Defining Special Destructor Behavior
5741 **
5742 ** These are special values for the destructor that is passed in as the
5743 ** final argument to routines like [sqlite3_result_blob()].  ^If the destructor
5744 ** argument is SQLITE_STATIC, it means that the content pointer is constant
5745 ** and will never change.  It does not need to be destroyed.  ^The
5746 ** SQLITE_TRANSIENT value means that the content will likely change in
5747 ** the near future and that SQLite should make its own private copy of
5748 ** the content before returning.
5749 **
5750 ** The typedef is necessary to work around problems in certain
5751 ** C++ compilers.
5752 */
5753 typedef void (*sqlite3_destructor_type)(void*);
5754 #define SQLITE_STATIC      ((sqlite3_destructor_type)0)
5755 #define SQLITE_TRANSIENT   ((sqlite3_destructor_type)-1)
5756 
5757 /*
5758 ** CAPI3REF: Setting The Result Of An SQL Function
5759 ** METHOD: sqlite3_context
5760 **
5761 ** These routines are used by the xFunc or xFinal callbacks that
5762 ** implement SQL functions and aggregates.  See
5763 ** [sqlite3_create_function()] and [sqlite3_create_function16()]
5764 ** for additional information.
5765 **
5766 ** These functions work very much like the [parameter binding] family of
5767 ** functions used to bind values to host parameters in prepared statements.
5768 ** Refer to the [SQL parameter] documentation for additional information.
5769 **
5770 ** ^The sqlite3_result_blob() interface sets the result from
5771 ** an application-defined function to be the BLOB whose content is pointed
5772 ** to by the second parameter and which is N bytes long where N is the
5773 ** third parameter.
5774 **
5775 ** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N)
5776 ** interfaces set the result of the application-defined function to be
5777 ** a BLOB containing all zero bytes and N bytes in size.
5778 **
5779 ** ^The sqlite3_result_double() interface sets the result from
5780 ** an application-defined function to be a floating point value specified
5781 ** by its 2nd argument.
5782 **
5783 ** ^The sqlite3_result_error() and sqlite3_result_error16() functions
5784 ** cause the implemented SQL function to throw an exception.
5785 ** ^SQLite uses the string pointed to by the
5786 ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
5787 ** as the text of an error message.  ^SQLite interprets the error
5788 ** message string from sqlite3_result_error() as UTF-8. ^SQLite
5789 ** interprets the string from sqlite3_result_error16() as UTF-16 using
5790 ** the same [byte-order determination rules] as [sqlite3_bind_text16()].
5791 ** ^If the third parameter to sqlite3_result_error()
5792 ** or sqlite3_result_error16() is negative then SQLite takes as the error
5793 ** message all text up through the first zero character.
5794 ** ^If the third parameter to sqlite3_result_error() or
5795 ** sqlite3_result_error16() is non-negative then SQLite takes that many
5796 ** bytes (not characters) from the 2nd parameter as the error message.
5797 ** ^The sqlite3_result_error() and sqlite3_result_error16()
5798 ** routines make a private copy of the error message text before
5799 ** they return.  Hence, the calling function can deallocate or
5800 ** modify the text after they return without harm.
5801 ** ^The sqlite3_result_error_code() function changes the error code
5802 ** returned by SQLite as a result of an error in a function.  ^By default,
5803 ** the error code is SQLITE_ERROR.  ^A subsequent call to sqlite3_result_error()
5804 ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
5805 **
5806 ** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an
5807 ** error indicating that a string or BLOB is too long to represent.
5808 **
5809 ** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an
5810 ** error indicating that a memory allocation failed.
5811 **
5812 ** ^The sqlite3_result_int() interface sets the return value
5813 ** of the application-defined function to be the 32-bit signed integer
5814 ** value given in the 2nd argument.
5815 ** ^The sqlite3_result_int64() interface sets the return value
5816 ** of the application-defined function to be the 64-bit signed integer
5817 ** value given in the 2nd argument.
5818 **
5819 ** ^The sqlite3_result_null() interface sets the return value
5820 ** of the application-defined function to be NULL.
5821 **
5822 ** ^The sqlite3_result_text(), sqlite3_result_text16(),
5823 ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
5824 ** set the return value of the application-defined function to be
5825 ** a text string which is represented as UTF-8, UTF-16 native byte order,
5826 ** UTF-16 little endian, or UTF-16 big endian, respectively.
5827 ** ^The sqlite3_result_text64() interface sets the return value of an
5828 ** application-defined function to be a text string in an encoding
5829 ** specified by the fifth (and last) parameter, which must be one
5830 ** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE].
5831 ** ^SQLite takes the text result from the application from
5832 ** the 2nd parameter of the sqlite3_result_text* interfaces.
5833 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
5834 ** is negative, then SQLite takes result text from the 2nd parameter
5835 ** through the first zero character.
5836 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
5837 ** is non-negative, then as many bytes (not characters) of the text
5838 ** pointed to by the 2nd parameter are taken as the application-defined
5839 ** function result.  If the 3rd parameter is non-negative, then it
5840 ** must be the byte offset into the string where the NUL terminator would
5841 ** appear if the string where NUL terminated.  If any NUL characters occur
5842 ** in the string at a byte offset that is less than the value of the 3rd
5843 ** parameter, then the resulting string will contain embedded NULs and the
5844 ** result of expressions operating on strings with embedded NULs is undefined.
5845 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
5846 ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
5847 ** function as the destructor on the text or BLOB result when it has
5848 ** finished using that result.
5849 ** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
5850 ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
5851 ** assumes that the text or BLOB result is in constant space and does not
5852 ** copy the content of the parameter nor call a destructor on the content
5853 ** when it has finished using that result.
5854 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
5855 ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
5856 ** then SQLite makes a copy of the result into space obtained
5857 ** from [sqlite3_malloc()] before it returns.
5858 **
5859 ** ^For the sqlite3_result_text16(), sqlite3_result_text16le(), and
5860 ** sqlite3_result_text16be() routines, and for sqlite3_result_text64()
5861 ** when the encoding is not UTF8, if the input UTF16 begins with a
5862 ** byte-order mark (BOM, U+FEFF) then the BOM is removed from the
5863 ** string and the rest of the string is interpreted according to the
5864 ** byte-order specified by the BOM.  ^The byte-order specified by
5865 ** the BOM at the beginning of the text overrides the byte-order
5866 ** specified by the interface procedure.  ^So, for example, if
5867 ** sqlite3_result_text16le() is invoked with text that begins
5868 ** with bytes 0xfe, 0xff (a big-endian byte-order mark) then the
5869 ** first two bytes of input are skipped and the remaining input
5870 ** is interpreted as UTF16BE text.
5871 **
5872 ** ^For UTF16 input text to the sqlite3_result_text16(),
5873 ** sqlite3_result_text16be(), sqlite3_result_text16le(), and
5874 ** sqlite3_result_text64() routines, if the text contains invalid
5875 ** UTF16 characters, the invalid characters might be converted
5876 ** into the unicode replacement character, U+FFFD.
5877 **
5878 ** ^The sqlite3_result_value() interface sets the result of
5879 ** the application-defined function to be a copy of the
5880 ** [unprotected sqlite3_value] object specified by the 2nd parameter.  ^The
5881 ** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
5882 ** so that the [sqlite3_value] specified in the parameter may change or
5883 ** be deallocated after sqlite3_result_value() returns without harm.
5884 ** ^A [protected sqlite3_value] object may always be used where an
5885 ** [unprotected sqlite3_value] object is required, so either
5886 ** kind of [sqlite3_value] object can be used with this interface.
5887 **
5888 ** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an
5889 ** SQL NULL value, just like [sqlite3_result_null(C)], except that it
5890 ** also associates the host-language pointer P or type T with that
5891 ** NULL value such that the pointer can be retrieved within an
5892 ** [application-defined SQL function] using [sqlite3_value_pointer()].
5893 ** ^If the D parameter is not NULL, then it is a pointer to a destructor
5894 ** for the P parameter.  ^SQLite invokes D with P as its only argument
5895 ** when SQLite is finished with P.  The T parameter should be a static
5896 ** string and preferably a string literal. The sqlite3_result_pointer()
5897 ** routine is part of the [pointer passing interface] added for SQLite 3.20.0.
5898 **
5899 ** If these routines are called from within the different thread
5900 ** than the one containing the application-defined function that received
5901 ** the [sqlite3_context] pointer, the results are undefined.
5902 */
5903 SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
5904 SQLITE_API void sqlite3_result_blob64(sqlite3_context*,const void*,
5905                            sqlite3_uint64,void(*)(void*));
5906 SQLITE_API void sqlite3_result_double(sqlite3_context*, double);
5907 SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int);
5908 SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int);
5909 SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*);
5910 SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*);
5911 SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int);
5912 SQLITE_API void sqlite3_result_int(sqlite3_context*, int);
5913 SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
5914 SQLITE_API void sqlite3_result_null(sqlite3_context*);
5915 SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
5916 SQLITE_API void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64,
5917                            void(*)(void*), unsigned char encoding);
5918 SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
5919 SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
5920 SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
5921 SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
5922 SQLITE_API void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*));
5923 SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n);
5924 SQLITE_API int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n);
5925 
5926 
5927 /*
5928 ** CAPI3REF: Setting The Subtype Of An SQL Function
5929 ** METHOD: sqlite3_context
5930 **
5931 ** The sqlite3_result_subtype(C,T) function causes the subtype of
5932 ** the result from the [application-defined SQL function] with
5933 ** [sqlite3_context] C to be the value T.  Only the lower 8 bits
5934 ** of the subtype T are preserved in current versions of SQLite;
5935 ** higher order bits are discarded.
5936 ** The number of subtype bytes preserved by SQLite might increase
5937 ** in future releases of SQLite.
5938 */
5939 SQLITE_API void sqlite3_result_subtype(sqlite3_context*,unsigned int);
5940 
5941 /*
5942 ** CAPI3REF: Define New Collating Sequences
5943 ** METHOD: sqlite3
5944 **
5945 ** ^These functions add, remove, or modify a [collation] associated
5946 ** with the [database connection] specified as the first argument.
5947 **
5948 ** ^The name of the collation is a UTF-8 string
5949 ** for sqlite3_create_collation() and sqlite3_create_collation_v2()
5950 ** and a UTF-16 string in native byte order for sqlite3_create_collation16().
5951 ** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
5952 ** considered to be the same name.
5953 **
5954 ** ^(The third argument (eTextRep) must be one of the constants:
5955 ** <ul>
5956 ** <li> [SQLITE_UTF8],
5957 ** <li> [SQLITE_UTF16LE],
5958 ** <li> [SQLITE_UTF16BE],
5959 ** <li> [SQLITE_UTF16], or
5960 ** <li> [SQLITE_UTF16_ALIGNED].
5961 ** </ul>)^
5962 ** ^The eTextRep argument determines the encoding of strings passed
5963 ** to the collating function callback, xCompare.
5964 ** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
5965 ** force strings to be UTF16 with native byte order.
5966 ** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
5967 ** on an even byte address.
5968 **
5969 ** ^The fourth argument, pArg, is an application data pointer that is passed
5970 ** through as the first argument to the collating function callback.
5971 **
5972 ** ^The fifth argument, xCompare, is a pointer to the collating function.
5973 ** ^Multiple collating functions can be registered using the same name but
5974 ** with different eTextRep parameters and SQLite will use whichever
5975 ** function requires the least amount of data transformation.
5976 ** ^If the xCompare argument is NULL then the collating function is
5977 ** deleted.  ^When all collating functions having the same name are deleted,
5978 ** that collation is no longer usable.
5979 **
5980 ** ^The collating function callback is invoked with a copy of the pArg
5981 ** application data pointer and with two strings in the encoding specified
5982 ** by the eTextRep argument.  The two integer parameters to the collating
5983 ** function callback are the length of the two strings, in bytes. The collating
5984 ** function must return an integer that is negative, zero, or positive
5985 ** if the first string is less than, equal to, or greater than the second,
5986 ** respectively.  A collating function must always return the same answer
5987 ** given the same inputs.  If two or more collating functions are registered
5988 ** to the same collation name (using different eTextRep values) then all
5989 ** must give an equivalent answer when invoked with equivalent strings.
5990 ** The collating function must obey the following properties for all
5991 ** strings A, B, and C:
5992 **
5993 ** <ol>
5994 ** <li> If A==B then B==A.
5995 ** <li> If A==B and B==C then A==C.
5996 ** <li> If A&lt;B THEN B&gt;A.
5997 ** <li> If A&lt;B and B&lt;C then A&lt;C.
5998 ** </ol>
5999 **
6000 ** If a collating function fails any of the above constraints and that
6001 ** collating function is registered and used, then the behavior of SQLite
6002 ** is undefined.
6003 **
6004 ** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
6005 ** with the addition that the xDestroy callback is invoked on pArg when
6006 ** the collating function is deleted.
6007 ** ^Collating functions are deleted when they are overridden by later
6008 ** calls to the collation creation functions or when the
6009 ** [database connection] is closed using [sqlite3_close()].
6010 **
6011 ** ^The xDestroy callback is <u>not</u> called if the
6012 ** sqlite3_create_collation_v2() function fails.  Applications that invoke
6013 ** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
6014 ** check the return code and dispose of the application data pointer
6015 ** themselves rather than expecting SQLite to deal with it for them.
6016 ** This is different from every other SQLite interface.  The inconsistency
6017 ** is unfortunate but cannot be changed without breaking backwards
6018 ** compatibility.
6019 **
6020 ** See also:  [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
6021 */
6022 SQLITE_API int sqlite3_create_collation(
6023   sqlite3*,
6024   const char *zName,
6025   int eTextRep,
6026   void *pArg,
6027   int(*xCompare)(void*,int,const void*,int,const void*)
6028 );
6029 SQLITE_API int sqlite3_create_collation_v2(
6030   sqlite3*,
6031   const char *zName,
6032   int eTextRep,
6033   void *pArg,
6034   int(*xCompare)(void*,int,const void*,int,const void*),
6035   void(*xDestroy)(void*)
6036 );
6037 SQLITE_API int sqlite3_create_collation16(
6038   sqlite3*,
6039   const void *zName,
6040   int eTextRep,
6041   void *pArg,
6042   int(*xCompare)(void*,int,const void*,int,const void*)
6043 );
6044 
6045 /*
6046 ** CAPI3REF: Collation Needed Callbacks
6047 ** METHOD: sqlite3
6048 **
6049 ** ^To avoid having to register all collation sequences before a database
6050 ** can be used, a single callback function may be registered with the
6051 ** [database connection] to be invoked whenever an undefined collation
6052 ** sequence is required.
6053 **
6054 ** ^If the function is registered using the sqlite3_collation_needed() API,
6055 ** then it is passed the names of undefined collation sequences as strings
6056 ** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
6057 ** the names are passed as UTF-16 in machine native byte order.
6058 ** ^A call to either function replaces the existing collation-needed callback.
6059 **
6060 ** ^(When the callback is invoked, the first argument passed is a copy
6061 ** of the second argument to sqlite3_collation_needed() or
6062 ** sqlite3_collation_needed16().  The second argument is the database
6063 ** connection.  The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
6064 ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
6065 ** sequence function required.  The fourth parameter is the name of the
6066 ** required collation sequence.)^
6067 **
6068 ** The callback function should register the desired collation using
6069 ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
6070 ** [sqlite3_create_collation_v2()].
6071 */
6072 SQLITE_API int sqlite3_collation_needed(
6073   sqlite3*,
6074   void*,
6075   void(*)(void*,sqlite3*,int eTextRep,const char*)
6076 );
6077 SQLITE_API int sqlite3_collation_needed16(
6078   sqlite3*,
6079   void*,
6080   void(*)(void*,sqlite3*,int eTextRep,const void*)
6081 );
6082 
6083 #ifdef SQLITE_ENABLE_CEROD
6084 /*
6085 ** Specify the activation key for a CEROD database.  Unless
6086 ** activated, none of the CEROD routines will work.
6087 */
6088 SQLITE_API void sqlite3_activate_cerod(
6089   const char *zPassPhrase        /* Activation phrase */
6090 );
6091 #endif
6092 
6093 /*
6094 ** CAPI3REF: Suspend Execution For A Short Time
6095 **
6096 ** The sqlite3_sleep() function causes the current thread to suspend execution
6097 ** for at least a number of milliseconds specified in its parameter.
6098 **
6099 ** If the operating system does not support sleep requests with
6100 ** millisecond time resolution, then the time will be rounded up to
6101 ** the nearest second. The number of milliseconds of sleep actually
6102 ** requested from the operating system is returned.
6103 **
6104 ** ^SQLite implements this interface by calling the xSleep()
6105 ** method of the default [sqlite3_vfs] object.  If the xSleep() method
6106 ** of the default VFS is not implemented correctly, or not implemented at
6107 ** all, then the behavior of sqlite3_sleep() may deviate from the description
6108 ** in the previous paragraphs.
6109 */
6110 SQLITE_API int sqlite3_sleep(int);
6111 
6112 /*
6113 ** CAPI3REF: Name Of The Folder Holding Temporary Files
6114 **
6115 ** ^(If this global variable is made to point to a string which is
6116 ** the name of a folder (a.k.a. directory), then all temporary files
6117 ** created by SQLite when using a built-in [sqlite3_vfs | VFS]
6118 ** will be placed in that directory.)^  ^If this variable
6119 ** is a NULL pointer, then SQLite performs a search for an appropriate
6120 ** temporary file directory.
6121 **
6122 ** Applications are strongly discouraged from using this global variable.
6123 ** It is required to set a temporary folder on Windows Runtime (WinRT).
6124 ** But for all other platforms, it is highly recommended that applications
6125 ** neither read nor write this variable.  This global variable is a relic
6126 ** that exists for backwards compatibility of legacy applications and should
6127 ** be avoided in new projects.
6128 **
6129 ** It is not safe to read or modify this variable in more than one
6130 ** thread at a time.  It is not safe to read or modify this variable
6131 ** if a [database connection] is being used at the same time in a separate
6132 ** thread.
6133 ** It is intended that this variable be set once
6134 ** as part of process initialization and before any SQLite interface
6135 ** routines have been called and that this variable remain unchanged
6136 ** thereafter.
6137 **
6138 ** ^The [temp_store_directory pragma] may modify this variable and cause
6139 ** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
6140 ** the [temp_store_directory pragma] always assumes that any string
6141 ** that this variable points to is held in memory obtained from
6142 ** [sqlite3_malloc] and the pragma may attempt to free that memory
6143 ** using [sqlite3_free].
6144 ** Hence, if this variable is modified directly, either it should be
6145 ** made NULL or made to point to memory obtained from [sqlite3_malloc]
6146 ** or else the use of the [temp_store_directory pragma] should be avoided.
6147 ** Except when requested by the [temp_store_directory pragma], SQLite
6148 ** does not free the memory that sqlite3_temp_directory points to.  If
6149 ** the application wants that memory to be freed, it must do
6150 ** so itself, taking care to only do so after all [database connection]
6151 ** objects have been destroyed.
6152 **
6153 ** <b>Note to Windows Runtime users:</b>  The temporary directory must be set
6154 ** prior to calling [sqlite3_open] or [sqlite3_open_v2].  Otherwise, various
6155 ** features that require the use of temporary files may fail.  Here is an
6156 ** example of how to do this using C++ with the Windows Runtime:
6157 **
6158 ** <blockquote><pre>
6159 ** LPCWSTR zPath = Windows::Storage::ApplicationData::Current->
6160 ** &nbsp;     TemporaryFolder->Path->Data();
6161 ** char zPathBuf&#91;MAX_PATH + 1&#93;;
6162 ** memset(zPathBuf, 0, sizeof(zPathBuf));
6163 ** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),
6164 ** &nbsp;     NULL, NULL);
6165 ** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);
6166 ** </pre></blockquote>
6167 */
6168 SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory;
6169 
6170 /*
6171 ** CAPI3REF: Name Of The Folder Holding Database Files
6172 **
6173 ** ^(If this global variable is made to point to a string which is
6174 ** the name of a folder (a.k.a. directory), then all database files
6175 ** specified with a relative pathname and created or accessed by
6176 ** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed
6177 ** to be relative to that directory.)^ ^If this variable is a NULL
6178 ** pointer, then SQLite assumes that all database files specified
6179 ** with a relative pathname are relative to the current directory
6180 ** for the process.  Only the windows VFS makes use of this global
6181 ** variable; it is ignored by the unix VFS.
6182 **
6183 ** Changing the value of this variable while a database connection is
6184 ** open can result in a corrupt database.
6185 **
6186 ** It is not safe to read or modify this variable in more than one
6187 ** thread at a time.  It is not safe to read or modify this variable
6188 ** if a [database connection] is being used at the same time in a separate
6189 ** thread.
6190 ** It is intended that this variable be set once
6191 ** as part of process initialization and before any SQLite interface
6192 ** routines have been called and that this variable remain unchanged
6193 ** thereafter.
6194 **
6195 ** ^The [data_store_directory pragma] may modify this variable and cause
6196 ** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
6197 ** the [data_store_directory pragma] always assumes that any string
6198 ** that this variable points to is held in memory obtained from
6199 ** [sqlite3_malloc] and the pragma may attempt to free that memory
6200 ** using [sqlite3_free].
6201 ** Hence, if this variable is modified directly, either it should be
6202 ** made NULL or made to point to memory obtained from [sqlite3_malloc]
6203 ** or else the use of the [data_store_directory pragma] should be avoided.
6204 */
6205 SQLITE_API SQLITE_EXTERN char *sqlite3_data_directory;
6206 
6207 /*
6208 ** CAPI3REF: Win32 Specific Interface
6209 **
6210 ** These interfaces are available only on Windows.  The
6211 ** [sqlite3_win32_set_directory] interface is used to set the value associated
6212 ** with the [sqlite3_temp_directory] or [sqlite3_data_directory] variable, to
6213 ** zValue, depending on the value of the type parameter.  The zValue parameter
6214 ** should be NULL to cause the previous value to be freed via [sqlite3_free];
6215 ** a non-NULL value will be copied into memory obtained from [sqlite3_malloc]
6216 ** prior to being used.  The [sqlite3_win32_set_directory] interface returns
6217 ** [SQLITE_OK] to indicate success, [SQLITE_ERROR] if the type is unsupported,
6218 ** or [SQLITE_NOMEM] if memory could not be allocated.  The value of the
6219 ** [sqlite3_data_directory] variable is intended to act as a replacement for
6220 ** the current directory on the sub-platforms of Win32 where that concept is
6221 ** not present, e.g. WinRT and UWP.  The [sqlite3_win32_set_directory8] and
6222 ** [sqlite3_win32_set_directory16] interfaces behave exactly the same as the
6223 ** sqlite3_win32_set_directory interface except the string parameter must be
6224 ** UTF-8 or UTF-16, respectively.
6225 */
6226 SQLITE_API int sqlite3_win32_set_directory(
6227   unsigned long type, /* Identifier for directory being set or reset */
6228   void *zValue        /* New value for directory being set or reset */
6229 );
6230 SQLITE_API int sqlite3_win32_set_directory8(unsigned long type, const char *zValue);
6231 SQLITE_API int sqlite3_win32_set_directory16(unsigned long type, const void *zValue);
6232 
6233 /*
6234 ** CAPI3REF: Win32 Directory Types
6235 **
6236 ** These macros are only available on Windows.  They define the allowed values
6237 ** for the type argument to the [sqlite3_win32_set_directory] interface.
6238 */
6239 #define SQLITE_WIN32_DATA_DIRECTORY_TYPE  1
6240 #define SQLITE_WIN32_TEMP_DIRECTORY_TYPE  2
6241 
6242 /*
6243 ** CAPI3REF: Test For Auto-Commit Mode
6244 ** KEYWORDS: {autocommit mode}
6245 ** METHOD: sqlite3
6246 **
6247 ** ^The sqlite3_get_autocommit() interface returns non-zero or
6248 ** zero if the given database connection is or is not in autocommit mode,
6249 ** respectively.  ^Autocommit mode is on by default.
6250 ** ^Autocommit mode is disabled by a [BEGIN] statement.
6251 ** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
6252 **
6253 ** If certain kinds of errors occur on a statement within a multi-statement
6254 ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
6255 ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
6256 ** transaction might be rolled back automatically.  The only way to
6257 ** find out whether SQLite automatically rolled back the transaction after
6258 ** an error is to use this function.
6259 **
6260 ** If another thread changes the autocommit status of the database
6261 ** connection while this routine is running, then the return value
6262 ** is undefined.
6263 */
6264 SQLITE_API int sqlite3_get_autocommit(sqlite3*);
6265 
6266 /*
6267 ** CAPI3REF: Find The Database Handle Of A Prepared Statement
6268 ** METHOD: sqlite3_stmt
6269 **
6270 ** ^The sqlite3_db_handle interface returns the [database connection] handle
6271 ** to which a [prepared statement] belongs.  ^The [database connection]
6272 ** returned by sqlite3_db_handle is the same [database connection]
6273 ** that was the first argument
6274 ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
6275 ** create the statement in the first place.
6276 */
6277 SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
6278 
6279 /*
6280 ** CAPI3REF: Return The Schema Name For A Database Connection
6281 ** METHOD: sqlite3
6282 **
6283 ** ^The sqlite3_db_name(D,N) interface returns a pointer to the schema name
6284 ** for the N-th database on database connection D, or a NULL pointer of N is
6285 ** out of range.  An N value of 0 means the main database file.  An N of 1 is
6286 ** the "temp" schema.  Larger values of N correspond to various ATTACH-ed
6287 ** databases.
6288 **
6289 ** Space to hold the string that is returned by sqlite3_db_name() is managed
6290 ** by SQLite itself.  The string might be deallocated by any operation that
6291 ** changes the schema, including [ATTACH] or [DETACH] or calls to
6292 ** [sqlite3_serialize()] or [sqlite3_deserialize()], even operations that
6293 ** occur on a different thread.  Applications that need to
6294 ** remember the string long-term should make their own copy.  Applications that
6295 ** are accessing the same database connection simultaneously on multiple
6296 ** threads should mutex-protect calls to this API and should make their own
6297 ** private copy of the result prior to releasing the mutex.
6298 */
6299 SQLITE_API const char *sqlite3_db_name(sqlite3 *db, int N);
6300 
6301 /*
6302 ** CAPI3REF: Return The Filename For A Database Connection
6303 ** METHOD: sqlite3
6304 **
6305 ** ^The sqlite3_db_filename(D,N) interface returns a pointer to the filename
6306 ** associated with database N of connection D.
6307 ** ^If there is no attached database N on the database
6308 ** connection D, or if database N is a temporary or in-memory database, then
6309 ** this function will return either a NULL pointer or an empty string.
6310 **
6311 ** ^The string value returned by this routine is owned and managed by
6312 ** the database connection.  ^The value will be valid until the database N
6313 ** is [DETACH]-ed or until the database connection closes.
6314 **
6315 ** ^The filename returned by this function is the output of the
6316 ** xFullPathname method of the [VFS].  ^In other words, the filename
6317 ** will be an absolute pathname, even if the filename used
6318 ** to open the database originally was a URI or relative pathname.
6319 **
6320 ** If the filename pointer returned by this routine is not NULL, then it
6321 ** can be used as the filename input parameter to these routines:
6322 ** <ul>
6323 ** <li> [sqlite3_uri_parameter()]
6324 ** <li> [sqlite3_uri_boolean()]
6325 ** <li> [sqlite3_uri_int64()]
6326 ** <li> [sqlite3_filename_database()]
6327 ** <li> [sqlite3_filename_journal()]
6328 ** <li> [sqlite3_filename_wal()]
6329 ** </ul>
6330 */
6331 SQLITE_API const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName);
6332 
6333 /*
6334 ** CAPI3REF: Determine if a database is read-only
6335 ** METHOD: sqlite3
6336 **
6337 ** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N
6338 ** of connection D is read-only, 0 if it is read/write, or -1 if N is not
6339 ** the name of a database on connection D.
6340 */
6341 SQLITE_API int sqlite3_db_readonly(sqlite3 *db, const char *zDbName);
6342 
6343 /*
6344 ** CAPI3REF: Determine the transaction state of a database
6345 ** METHOD: sqlite3
6346 **
6347 ** ^The sqlite3_txn_state(D,S) interface returns the current
6348 ** [transaction state] of schema S in database connection D.  ^If S is NULL,
6349 ** then the highest transaction state of any schema on database connection D
6350 ** is returned.  Transaction states are (in order of lowest to highest):
6351 ** <ol>
6352 ** <li value="0"> SQLITE_TXN_NONE
6353 ** <li value="1"> SQLITE_TXN_READ
6354 ** <li value="2"> SQLITE_TXN_WRITE
6355 ** </ol>
6356 ** ^If the S argument to sqlite3_txn_state(D,S) is not the name of
6357 ** a valid schema, then -1 is returned.
6358 */
6359 SQLITE_API int sqlite3_txn_state(sqlite3*,const char *zSchema);
6360 
6361 /*
6362 ** CAPI3REF: Allowed return values from [sqlite3_txn_state()]
6363 ** KEYWORDS: {transaction state}
6364 **
6365 ** These constants define the current transaction state of a database file.
6366 ** ^The [sqlite3_txn_state(D,S)] interface returns one of these
6367 ** constants in order to describe the transaction state of schema S
6368 ** in [database connection] D.
6369 **
6370 ** <dl>
6371 ** [[SQLITE_TXN_NONE]] <dt>SQLITE_TXN_NONE</dt>
6372 ** <dd>The SQLITE_TXN_NONE state means that no transaction is currently
6373 ** pending.</dd>
6374 **
6375 ** [[SQLITE_TXN_READ]] <dt>SQLITE_TXN_READ</dt>
6376 ** <dd>The SQLITE_TXN_READ state means that the database is currently
6377 ** in a read transaction.  Content has been read from the database file
6378 ** but nothing in the database file has changed.  The transaction state
6379 ** will advanced to SQLITE_TXN_WRITE if any changes occur and there are
6380 ** no other conflicting concurrent write transactions.  The transaction
6381 ** state will revert to SQLITE_TXN_NONE following a [ROLLBACK] or
6382 ** [COMMIT].</dd>
6383 **
6384 ** [[SQLITE_TXN_WRITE]] <dt>SQLITE_TXN_WRITE</dt>
6385 ** <dd>The SQLITE_TXN_WRITE state means that the database is currently
6386 ** in a write transaction.  Content has been written to the database file
6387 ** but has not yet committed.  The transaction state will change to
6388 ** to SQLITE_TXN_NONE at the next [ROLLBACK] or [COMMIT].</dd>
6389 */
6390 #define SQLITE_TXN_NONE  0
6391 #define SQLITE_TXN_READ  1
6392 #define SQLITE_TXN_WRITE 2
6393 
6394 /*
6395 ** CAPI3REF: Find the next prepared statement
6396 ** METHOD: sqlite3
6397 **
6398 ** ^This interface returns a pointer to the next [prepared statement] after
6399 ** pStmt associated with the [database connection] pDb.  ^If pStmt is NULL
6400 ** then this interface returns a pointer to the first prepared statement
6401 ** associated with the database connection pDb.  ^If no prepared statement
6402 ** satisfies the conditions of this routine, it returns NULL.
6403 **
6404 ** The [database connection] pointer D in a call to
6405 ** [sqlite3_next_stmt(D,S)] must refer to an open database
6406 ** connection and in particular must not be a NULL pointer.
6407 */
6408 SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
6409 
6410 /*
6411 ** CAPI3REF: Commit And Rollback Notification Callbacks
6412 ** METHOD: sqlite3
6413 **
6414 ** ^The sqlite3_commit_hook() interface registers a callback
6415 ** function to be invoked whenever a transaction is [COMMIT | committed].
6416 ** ^Any callback set by a previous call to sqlite3_commit_hook()
6417 ** for the same database connection is overridden.
6418 ** ^The sqlite3_rollback_hook() interface registers a callback
6419 ** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
6420 ** ^Any callback set by a previous call to sqlite3_rollback_hook()
6421 ** for the same database connection is overridden.
6422 ** ^The pArg argument is passed through to the callback.
6423 ** ^If the callback on a commit hook function returns non-zero,
6424 ** then the commit is converted into a rollback.
6425 **
6426 ** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
6427 ** return the P argument from the previous call of the same function
6428 ** on the same [database connection] D, or NULL for
6429 ** the first call for each function on D.
6430 **
6431 ** The commit and rollback hook callbacks are not reentrant.
6432 ** The callback implementation must not do anything that will modify
6433 ** the database connection that invoked the callback.  Any actions
6434 ** to modify the database connection must be deferred until after the
6435 ** completion of the [sqlite3_step()] call that triggered the commit
6436 ** or rollback hook in the first place.
6437 ** Note that running any other SQL statements, including SELECT statements,
6438 ** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
6439 ** the database connections for the meaning of "modify" in this paragraph.
6440 **
6441 ** ^Registering a NULL function disables the callback.
6442 **
6443 ** ^When the commit hook callback routine returns zero, the [COMMIT]
6444 ** operation is allowed to continue normally.  ^If the commit hook
6445 ** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
6446 ** ^The rollback hook is invoked on a rollback that results from a commit
6447 ** hook returning non-zero, just as it would be with any other rollback.
6448 **
6449 ** ^For the purposes of this API, a transaction is said to have been
6450 ** rolled back if an explicit "ROLLBACK" statement is executed, or
6451 ** an error or constraint causes an implicit rollback to occur.
6452 ** ^The rollback callback is not invoked if a transaction is
6453 ** automatically rolled back because the database connection is closed.
6454 **
6455 ** See also the [sqlite3_update_hook()] interface.
6456 */
6457 SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
6458 SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
6459 
6460 /*
6461 ** CAPI3REF: Autovacuum Compaction Amount Callback
6462 ** METHOD: sqlite3
6463 **
6464 ** ^The sqlite3_autovacuum_pages(D,C,P,X) interface registers a callback
6465 ** function C that is invoked prior to each autovacuum of the database
6466 ** file.  ^The callback is passed a copy of the generic data pointer (P),
6467 ** the schema-name of the attached database that is being autovacuumed,
6468 ** the the size of the database file in pages, the number of free pages,
6469 ** and the number of bytes per page, respectively.  The callback should
6470 ** return the number of free pages that should be removed by the
6471 ** autovacuum.  ^If the callback returns zero, then no autovacuum happens.
6472 ** ^If the value returned is greater than or equal to the number of
6473 ** free pages, then a complete autovacuum happens.
6474 **
6475 ** <p>^If there are multiple ATTACH-ed database files that are being
6476 ** modified as part of a transaction commit, then the autovacuum pages
6477 ** callback is invoked separately for each file.
6478 **
6479 ** <p><b>The callback is not reentrant.</b> The callback function should
6480 ** not attempt to invoke any other SQLite interface.  If it does, bad
6481 ** things may happen, including segmentation faults and corrupt database
6482 ** files.  The callback function should be a simple function that
6483 ** does some arithmetic on its input parameters and returns a result.
6484 **
6485 ** ^The X parameter to sqlite3_autovacuum_pages(D,C,P,X) is an optional
6486 ** destructor for the P parameter.  ^If X is not NULL, then X(P) is
6487 ** invoked whenever the database connection closes or when the callback
6488 ** is overwritten by another invocation of sqlite3_autovacuum_pages().
6489 **
6490 ** <p>^There is only one autovacuum pages callback per database connection.
6491 ** ^Each call to the sqlite3_autovacuum_pages() interface overrides all
6492 ** previous invocations for that database connection.  ^If the callback
6493 ** argument (C) to sqlite3_autovacuum_pages(D,C,P,X) is a NULL pointer,
6494 ** then the autovacuum steps callback is cancelled.  The return value
6495 ** from sqlite3_autovacuum_pages() is normally SQLITE_OK, but might
6496 ** be some other error code if something goes wrong.  The current
6497 ** implementation will only return SQLITE_OK or SQLITE_MISUSE, but other
6498 ** return codes might be added in future releases.
6499 **
6500 ** <p>If no autovacuum pages callback is specified (the usual case) or
6501 ** a NULL pointer is provided for the callback,
6502 ** then the default behavior is to vacuum all free pages.  So, in other
6503 ** words, the default behavior is the same as if the callback function
6504 ** were something like this:
6505 **
6506 ** <blockquote><pre>
6507 ** &nbsp;   unsigned int demonstration_autovac_pages_callback(
6508 ** &nbsp;     void *pClientData,
6509 ** &nbsp;     const char *zSchema,
6510 ** &nbsp;     unsigned int nDbPage,
6511 ** &nbsp;     unsigned int nFreePage,
6512 ** &nbsp;     unsigned int nBytePerPage
6513 ** &nbsp;   ){
6514 ** &nbsp;     return nFreePage;
6515 ** &nbsp;   }
6516 ** </pre></blockquote>
6517 */
6518 SQLITE_API int sqlite3_autovacuum_pages(
6519   sqlite3 *db,
6520   unsigned int(*)(void*,const char*,unsigned int,unsigned int,unsigned int),
6521   void*,
6522   void(*)(void*)
6523 );
6524 
6525 
6526 /*
6527 ** CAPI3REF: Data Change Notification Callbacks
6528 ** METHOD: sqlite3
6529 **
6530 ** ^The sqlite3_update_hook() interface registers a callback function
6531 ** with the [database connection] identified by the first argument
6532 ** to be invoked whenever a row is updated, inserted or deleted in
6533 ** a [rowid table].
6534 ** ^Any callback set by a previous call to this function
6535 ** for the same database connection is overridden.
6536 **
6537 ** ^The second argument is a pointer to the function to invoke when a
6538 ** row is updated, inserted or deleted in a rowid table.
6539 ** ^The first argument to the callback is a copy of the third argument
6540 ** to sqlite3_update_hook().
6541 ** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
6542 ** or [SQLITE_UPDATE], depending on the operation that caused the callback
6543 ** to be invoked.
6544 ** ^The third and fourth arguments to the callback contain pointers to the
6545 ** database and table name containing the affected row.
6546 ** ^The final callback parameter is the [rowid] of the row.
6547 ** ^In the case of an update, this is the [rowid] after the update takes place.
6548 **
6549 ** ^(The update hook is not invoked when internal system tables are
6550 ** modified (i.e. sqlite_sequence).)^
6551 ** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified.
6552 **
6553 ** ^In the current implementation, the update hook
6554 ** is not invoked when conflicting rows are deleted because of an
6555 ** [ON CONFLICT | ON CONFLICT REPLACE] clause.  ^Nor is the update hook
6556 ** invoked when rows are deleted using the [truncate optimization].
6557 ** The exceptions defined in this paragraph might change in a future
6558 ** release of SQLite.
6559 **
6560 ** The update hook implementation must not do anything that will modify
6561 ** the database connection that invoked the update hook.  Any actions
6562 ** to modify the database connection must be deferred until after the
6563 ** completion of the [sqlite3_step()] call that triggered the update hook.
6564 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
6565 ** database connections for the meaning of "modify" in this paragraph.
6566 **
6567 ** ^The sqlite3_update_hook(D,C,P) function
6568 ** returns the P argument from the previous call
6569 ** on the same [database connection] D, or NULL for
6570 ** the first call on D.
6571 **
6572 ** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()],
6573 ** and [sqlite3_preupdate_hook()] interfaces.
6574 */
6575 SQLITE_API void *sqlite3_update_hook(
6576   sqlite3*,
6577   void(*)(void *,int ,char const *,char const *,sqlite3_int64),
6578   void*
6579 );
6580 
6581 /*
6582 ** CAPI3REF: Enable Or Disable Shared Pager Cache
6583 **
6584 ** ^(This routine enables or disables the sharing of the database cache
6585 ** and schema data structures between [database connection | connections]
6586 ** to the same database. Sharing is enabled if the argument is true
6587 ** and disabled if the argument is false.)^
6588 **
6589 ** ^Cache sharing is enabled and disabled for an entire process.
6590 ** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]).
6591 ** In prior versions of SQLite,
6592 ** sharing was enabled or disabled for each thread separately.
6593 **
6594 ** ^(The cache sharing mode set by this interface effects all subsequent
6595 ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
6596 ** Existing database connections continue to use the sharing mode
6597 ** that was in effect at the time they were opened.)^
6598 **
6599 ** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
6600 ** successfully.  An [error code] is returned otherwise.)^
6601 **
6602 ** ^Shared cache is disabled by default. It is recommended that it stay
6603 ** that way.  In other words, do not use this routine.  This interface
6604 ** continues to be provided for historical compatibility, but its use is
6605 ** discouraged.  Any use of shared cache is discouraged.  If shared cache
6606 ** must be used, it is recommended that shared cache only be enabled for
6607 ** individual database connections using the [sqlite3_open_v2()] interface
6608 ** with the [SQLITE_OPEN_SHAREDCACHE] flag.
6609 **
6610 ** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0
6611 ** and will always return SQLITE_MISUSE. On those systems,
6612 ** shared cache mode should be enabled per-database connection via
6613 ** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE].
6614 **
6615 ** This interface is threadsafe on processors where writing a
6616 ** 32-bit integer is atomic.
6617 **
6618 ** See Also:  [SQLite Shared-Cache Mode]
6619 */
6620 SQLITE_API int sqlite3_enable_shared_cache(int);
6621 
6622 /*
6623 ** CAPI3REF: Attempt To Free Heap Memory
6624 **
6625 ** ^The sqlite3_release_memory() interface attempts to free N bytes
6626 ** of heap memory by deallocating non-essential memory allocations
6627 ** held by the database library.   Memory used to cache database
6628 ** pages to improve performance is an example of non-essential memory.
6629 ** ^sqlite3_release_memory() returns the number of bytes actually freed,
6630 ** which might be more or less than the amount requested.
6631 ** ^The sqlite3_release_memory() routine is a no-op returning zero
6632 ** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
6633 **
6634 ** See also: [sqlite3_db_release_memory()]
6635 */
6636 SQLITE_API int sqlite3_release_memory(int);
6637 
6638 /*
6639 ** CAPI3REF: Free Memory Used By A Database Connection
6640 ** METHOD: sqlite3
6641 **
6642 ** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap
6643 ** memory as possible from database connection D. Unlike the
6644 ** [sqlite3_release_memory()] interface, this interface is in effect even
6645 ** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
6646 ** omitted.
6647 **
6648 ** See also: [sqlite3_release_memory()]
6649 */
6650 SQLITE_API int sqlite3_db_release_memory(sqlite3*);
6651 
6652 /*
6653 ** CAPI3REF: Impose A Limit On Heap Size
6654 **
6655 ** These interfaces impose limits on the amount of heap memory that will be
6656 ** by all database connections within a single process.
6657 **
6658 ** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
6659 ** soft limit on the amount of heap memory that may be allocated by SQLite.
6660 ** ^SQLite strives to keep heap memory utilization below the soft heap
6661 ** limit by reducing the number of pages held in the page cache
6662 ** as heap memory usages approaches the limit.
6663 ** ^The soft heap limit is "soft" because even though SQLite strives to stay
6664 ** below the limit, it will exceed the limit rather than generate
6665 ** an [SQLITE_NOMEM] error.  In other words, the soft heap limit
6666 ** is advisory only.
6667 **
6668 ** ^The sqlite3_hard_heap_limit64(N) interface sets a hard upper bound of
6669 ** N bytes on the amount of memory that will be allocated.  ^The
6670 ** sqlite3_hard_heap_limit64(N) interface is similar to
6671 ** sqlite3_soft_heap_limit64(N) except that memory allocations will fail
6672 ** when the hard heap limit is reached.
6673 **
6674 ** ^The return value from both sqlite3_soft_heap_limit64() and
6675 ** sqlite3_hard_heap_limit64() is the size of
6676 ** the heap limit prior to the call, or negative in the case of an
6677 ** error.  ^If the argument N is negative
6678 ** then no change is made to the heap limit.  Hence, the current
6679 ** size of heap limits can be determined by invoking
6680 ** sqlite3_soft_heap_limit64(-1) or sqlite3_hard_heap_limit(-1).
6681 **
6682 ** ^Setting the heap limits to zero disables the heap limiter mechanism.
6683 **
6684 ** ^The soft heap limit may not be greater than the hard heap limit.
6685 ** ^If the hard heap limit is enabled and if sqlite3_soft_heap_limit(N)
6686 ** is invoked with a value of N that is greater than the hard heap limit,
6687 ** the the soft heap limit is set to the value of the hard heap limit.
6688 ** ^The soft heap limit is automatically enabled whenever the hard heap
6689 ** limit is enabled. ^When sqlite3_hard_heap_limit64(N) is invoked and
6690 ** the soft heap limit is outside the range of 1..N, then the soft heap
6691 ** limit is set to N.  ^Invoking sqlite3_soft_heap_limit64(0) when the
6692 ** hard heap limit is enabled makes the soft heap limit equal to the
6693 ** hard heap limit.
6694 **
6695 ** The memory allocation limits can also be adjusted using
6696 ** [PRAGMA soft_heap_limit] and [PRAGMA hard_heap_limit].
6697 **
6698 ** ^(The heap limits are not enforced in the current implementation
6699 ** if one or more of following conditions are true:
6700 **
6701 ** <ul>
6702 ** <li> The limit value is set to zero.
6703 ** <li> Memory accounting is disabled using a combination of the
6704 **      [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
6705 **      the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
6706 ** <li> An alternative page cache implementation is specified using
6707 **      [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
6708 ** <li> The page cache allocates from its own memory pool supplied
6709 **      by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
6710 **      from the heap.
6711 ** </ul>)^
6712 **
6713 ** The circumstances under which SQLite will enforce the heap limits may
6714 ** changes in future releases of SQLite.
6715 */
6716 SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);
6717 SQLITE_API sqlite3_int64 sqlite3_hard_heap_limit64(sqlite3_int64 N);
6718 
6719 /*
6720 ** CAPI3REF: Deprecated Soft Heap Limit Interface
6721 ** DEPRECATED
6722 **
6723 ** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
6724 ** interface.  This routine is provided for historical compatibility
6725 ** only.  All new applications should use the
6726 ** [sqlite3_soft_heap_limit64()] interface rather than this one.
6727 */
6728 SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N);
6729 
6730 
6731 /*
6732 ** CAPI3REF: Extract Metadata About A Column Of A Table
6733 ** METHOD: sqlite3
6734 **
6735 ** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns
6736 ** information about column C of table T in database D
6737 ** on [database connection] X.)^  ^The sqlite3_table_column_metadata()
6738 ** interface returns SQLITE_OK and fills in the non-NULL pointers in
6739 ** the final five arguments with appropriate values if the specified
6740 ** column exists.  ^The sqlite3_table_column_metadata() interface returns
6741 ** SQLITE_ERROR if the specified column does not exist.
6742 ** ^If the column-name parameter to sqlite3_table_column_metadata() is a
6743 ** NULL pointer, then this routine simply checks for the existence of the
6744 ** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it
6745 ** does not.  If the table name parameter T in a call to
6746 ** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is
6747 ** undefined behavior.
6748 **
6749 ** ^The column is identified by the second, third and fourth parameters to
6750 ** this function. ^(The second parameter is either the name of the database
6751 ** (i.e. "main", "temp", or an attached database) containing the specified
6752 ** table or NULL.)^ ^If it is NULL, then all attached databases are searched
6753 ** for the table using the same algorithm used by the database engine to
6754 ** resolve unqualified table references.
6755 **
6756 ** ^The third and fourth parameters to this function are the table and column
6757 ** name of the desired column, respectively.
6758 **
6759 ** ^Metadata is returned by writing to the memory locations passed as the 5th
6760 ** and subsequent parameters to this function. ^Any of these arguments may be
6761 ** NULL, in which case the corresponding element of metadata is omitted.
6762 **
6763 ** ^(<blockquote>
6764 ** <table border="1">
6765 ** <tr><th> Parameter <th> Output<br>Type <th>  Description
6766 **
6767 ** <tr><td> 5th <td> const char* <td> Data type
6768 ** <tr><td> 6th <td> const char* <td> Name of default collation sequence
6769 ** <tr><td> 7th <td> int         <td> True if column has a NOT NULL constraint
6770 ** <tr><td> 8th <td> int         <td> True if column is part of the PRIMARY KEY
6771 ** <tr><td> 9th <td> int         <td> True if column is [AUTOINCREMENT]
6772 ** </table>
6773 ** </blockquote>)^
6774 **
6775 ** ^The memory pointed to by the character pointers returned for the
6776 ** declaration type and collation sequence is valid until the next
6777 ** call to any SQLite API function.
6778 **
6779 ** ^If the specified table is actually a view, an [error code] is returned.
6780 **
6781 ** ^If the specified column is "rowid", "oid" or "_rowid_" and the table
6782 ** is not a [WITHOUT ROWID] table and an
6783 ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
6784 ** parameters are set for the explicitly declared column. ^(If there is no
6785 ** [INTEGER PRIMARY KEY] column, then the outputs
6786 ** for the [rowid] are set as follows:
6787 **
6788 ** <pre>
6789 **     data type: "INTEGER"
6790 **     collation sequence: "BINARY"
6791 **     not null: 0
6792 **     primary key: 1
6793 **     auto increment: 0
6794 ** </pre>)^
6795 **
6796 ** ^This function causes all database schemas to be read from disk and
6797 ** parsed, if that has not already been done, and returns an error if
6798 ** any errors are encountered while loading the schema.
6799 */
6800 SQLITE_API int sqlite3_table_column_metadata(
6801   sqlite3 *db,                /* Connection handle */
6802   const char *zDbName,        /* Database name or NULL */
6803   const char *zTableName,     /* Table name */
6804   const char *zColumnName,    /* Column name */
6805   char const **pzDataType,    /* OUTPUT: Declared data type */
6806   char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
6807   int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
6808   int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
6809   int *pAutoinc               /* OUTPUT: True if column is auto-increment */
6810 );
6811 
6812 /*
6813 ** CAPI3REF: Load An Extension
6814 ** METHOD: sqlite3
6815 **
6816 ** ^This interface loads an SQLite extension library from the named file.
6817 **
6818 ** ^The sqlite3_load_extension() interface attempts to load an
6819 ** [SQLite extension] library contained in the file zFile.  If
6820 ** the file cannot be loaded directly, attempts are made to load
6821 ** with various operating-system specific extensions added.
6822 ** So for example, if "samplelib" cannot be loaded, then names like
6823 ** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might
6824 ** be tried also.
6825 **
6826 ** ^The entry point is zProc.
6827 ** ^(zProc may be 0, in which case SQLite will try to come up with an
6828 ** entry point name on its own.  It first tries "sqlite3_extension_init".
6829 ** If that does not work, it constructs a name "sqlite3_X_init" where the
6830 ** X is consists of the lower-case equivalent of all ASCII alphabetic
6831 ** characters in the filename from the last "/" to the first following
6832 ** "." and omitting any initial "lib".)^
6833 ** ^The sqlite3_load_extension() interface returns
6834 ** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
6835 ** ^If an error occurs and pzErrMsg is not 0, then the
6836 ** [sqlite3_load_extension()] interface shall attempt to
6837 ** fill *pzErrMsg with error message text stored in memory
6838 ** obtained from [sqlite3_malloc()]. The calling function
6839 ** should free this memory by calling [sqlite3_free()].
6840 **
6841 ** ^Extension loading must be enabled using
6842 ** [sqlite3_enable_load_extension()] or
6843 ** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL)
6844 ** prior to calling this API,
6845 ** otherwise an error will be returned.
6846 **
6847 ** <b>Security warning:</b> It is recommended that the
6848 ** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this
6849 ** interface.  The use of the [sqlite3_enable_load_extension()] interface
6850 ** should be avoided.  This will keep the SQL function [load_extension()]
6851 ** disabled and prevent SQL injections from giving attackers
6852 ** access to extension loading capabilities.
6853 **
6854 ** See also the [load_extension() SQL function].
6855 */
6856 SQLITE_API int sqlite3_load_extension(
6857   sqlite3 *db,          /* Load the extension into this database connection */
6858   const char *zFile,    /* Name of the shared library containing extension */
6859   const char *zProc,    /* Entry point.  Derived from zFile if 0 */
6860   char **pzErrMsg       /* Put error message here if not 0 */
6861 );
6862 
6863 /*
6864 ** CAPI3REF: Enable Or Disable Extension Loading
6865 ** METHOD: sqlite3
6866 **
6867 ** ^So as not to open security holes in older applications that are
6868 ** unprepared to deal with [extension loading], and as a means of disabling
6869 ** [extension loading] while evaluating user-entered SQL, the following API
6870 ** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
6871 **
6872 ** ^Extension loading is off by default.
6873 ** ^Call the sqlite3_enable_load_extension() routine with onoff==1
6874 ** to turn extension loading on and call it with onoff==0 to turn
6875 ** it back off again.
6876 **
6877 ** ^This interface enables or disables both the C-API
6878 ** [sqlite3_load_extension()] and the SQL function [load_extension()].
6879 ** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..)
6880 ** to enable or disable only the C-API.)^
6881 **
6882 ** <b>Security warning:</b> It is recommended that extension loading
6883 ** be enabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method
6884 ** rather than this interface, so the [load_extension()] SQL function
6885 ** remains disabled. This will prevent SQL injections from giving attackers
6886 ** access to extension loading capabilities.
6887 */
6888 SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
6889 
6890 /*
6891 ** CAPI3REF: Automatically Load Statically Linked Extensions
6892 **
6893 ** ^This interface causes the xEntryPoint() function to be invoked for
6894 ** each new [database connection] that is created.  The idea here is that
6895 ** xEntryPoint() is the entry point for a statically linked [SQLite extension]
6896 ** that is to be automatically loaded into all new database connections.
6897 **
6898 ** ^(Even though the function prototype shows that xEntryPoint() takes
6899 ** no arguments and returns void, SQLite invokes xEntryPoint() with three
6900 ** arguments and expects an integer result as if the signature of the
6901 ** entry point where as follows:
6902 **
6903 ** <blockquote><pre>
6904 ** &nbsp;  int xEntryPoint(
6905 ** &nbsp;    sqlite3 *db,
6906 ** &nbsp;    const char **pzErrMsg,
6907 ** &nbsp;    const struct sqlite3_api_routines *pThunk
6908 ** &nbsp;  );
6909 ** </pre></blockquote>)^
6910 **
6911 ** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
6912 ** point to an appropriate error message (obtained from [sqlite3_mprintf()])
6913 ** and return an appropriate [error code].  ^SQLite ensures that *pzErrMsg
6914 ** is NULL before calling the xEntryPoint().  ^SQLite will invoke
6915 ** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns.  ^If any
6916 ** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
6917 ** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
6918 **
6919 ** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
6920 ** on the list of automatic extensions is a harmless no-op. ^No entry point
6921 ** will be called more than once for each database connection that is opened.
6922 **
6923 ** See also: [sqlite3_reset_auto_extension()]
6924 ** and [sqlite3_cancel_auto_extension()]
6925 */
6926 SQLITE_API int sqlite3_auto_extension(void(*xEntryPoint)(void));
6927 
6928 /*
6929 ** CAPI3REF: Cancel Automatic Extension Loading
6930 **
6931 ** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the
6932 ** initialization routine X that was registered using a prior call to
6933 ** [sqlite3_auto_extension(X)].  ^The [sqlite3_cancel_auto_extension(X)]
6934 ** routine returns 1 if initialization routine X was successfully
6935 ** unregistered and it returns 0 if X was not on the list of initialization
6936 ** routines.
6937 */
6938 SQLITE_API int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void));
6939 
6940 /*
6941 ** CAPI3REF: Reset Automatic Extension Loading
6942 **
6943 ** ^This interface disables all automatic extensions previously
6944 ** registered using [sqlite3_auto_extension()].
6945 */
6946 SQLITE_API void sqlite3_reset_auto_extension(void);
6947 
6948 /*
6949 ** The interface to the virtual-table mechanism is currently considered
6950 ** to be experimental.  The interface might change in incompatible ways.
6951 ** If this is a problem for you, do not use the interface at this time.
6952 **
6953 ** When the virtual-table mechanism stabilizes, we will declare the
6954 ** interface fixed, support it indefinitely, and remove this comment.
6955 */
6956 
6957 /*
6958 ** Structures used by the virtual table interface
6959 */
6960 typedef struct sqlite3_vtab sqlite3_vtab;
6961 typedef struct sqlite3_index_info sqlite3_index_info;
6962 typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
6963 typedef struct sqlite3_module sqlite3_module;
6964 
6965 /*
6966 ** CAPI3REF: Virtual Table Object
6967 ** KEYWORDS: sqlite3_module {virtual table module}
6968 **
6969 ** This structure, sometimes called a "virtual table module",
6970 ** defines the implementation of a [virtual table].
6971 ** This structure consists mostly of methods for the module.
6972 **
6973 ** ^A virtual table module is created by filling in a persistent
6974 ** instance of this structure and passing a pointer to that instance
6975 ** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
6976 ** ^The registration remains valid until it is replaced by a different
6977 ** module or until the [database connection] closes.  The content
6978 ** of this structure must not change while it is registered with
6979 ** any database connection.
6980 */
6981 struct sqlite3_module {
6982   int iVersion;
6983   int (*xCreate)(sqlite3*, void *pAux,
6984                int argc, const char *const*argv,
6985                sqlite3_vtab **ppVTab, char**);
6986   int (*xConnect)(sqlite3*, void *pAux,
6987                int argc, const char *const*argv,
6988                sqlite3_vtab **ppVTab, char**);
6989   int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
6990   int (*xDisconnect)(sqlite3_vtab *pVTab);
6991   int (*xDestroy)(sqlite3_vtab *pVTab);
6992   int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
6993   int (*xClose)(sqlite3_vtab_cursor*);
6994   int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
6995                 int argc, sqlite3_value **argv);
6996   int (*xNext)(sqlite3_vtab_cursor*);
6997   int (*xEof)(sqlite3_vtab_cursor*);
6998   int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
6999   int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
7000   int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
7001   int (*xBegin)(sqlite3_vtab *pVTab);
7002   int (*xSync)(sqlite3_vtab *pVTab);
7003   int (*xCommit)(sqlite3_vtab *pVTab);
7004   int (*xRollback)(sqlite3_vtab *pVTab);
7005   int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
7006                        void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
7007                        void **ppArg);
7008   int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
7009   /* The methods above are in version 1 of the sqlite_module object. Those
7010   ** below are for version 2 and greater. */
7011   int (*xSavepoint)(sqlite3_vtab *pVTab, int);
7012   int (*xRelease)(sqlite3_vtab *pVTab, int);
7013   int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
7014   /* The methods above are in versions 1 and 2 of the sqlite_module object.
7015   ** Those below are for version 3 and greater. */
7016   int (*xShadowName)(const char*);
7017 };
7018 
7019 /*
7020 ** CAPI3REF: Virtual Table Indexing Information
7021 ** KEYWORDS: sqlite3_index_info
7022 **
7023 ** The sqlite3_index_info structure and its substructures is used as part
7024 ** of the [virtual table] interface to
7025 ** pass information into and receive the reply from the [xBestIndex]
7026 ** method of a [virtual table module].  The fields under **Inputs** are the
7027 ** inputs to xBestIndex and are read-only.  xBestIndex inserts its
7028 ** results into the **Outputs** fields.
7029 **
7030 ** ^(The aConstraint[] array records WHERE clause constraints of the form:
7031 **
7032 ** <blockquote>column OP expr</blockquote>
7033 **
7034 ** where OP is =, &lt;, &lt;=, &gt;, or &gt;=.)^  ^(The particular operator is
7035 ** stored in aConstraint[].op using one of the
7036 ** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
7037 ** ^(The index of the column is stored in
7038 ** aConstraint[].iColumn.)^  ^(aConstraint[].usable is TRUE if the
7039 ** expr on the right-hand side can be evaluated (and thus the constraint
7040 ** is usable) and false if it cannot.)^
7041 **
7042 ** ^The optimizer automatically inverts terms of the form "expr OP column"
7043 ** and makes other simplifications to the WHERE clause in an attempt to
7044 ** get as many WHERE clause terms into the form shown above as possible.
7045 ** ^The aConstraint[] array only reports WHERE clause terms that are
7046 ** relevant to the particular virtual table being queried.
7047 **
7048 ** ^Information about the ORDER BY clause is stored in aOrderBy[].
7049 ** ^Each term of aOrderBy records a column of the ORDER BY clause.
7050 **
7051 ** The colUsed field indicates which columns of the virtual table may be
7052 ** required by the current scan. Virtual table columns are numbered from
7053 ** zero in the order in which they appear within the CREATE TABLE statement
7054 ** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62),
7055 ** the corresponding bit is set within the colUsed mask if the column may be
7056 ** required by SQLite. If the table has at least 64 columns and any column
7057 ** to the right of the first 63 is required, then bit 63 of colUsed is also
7058 ** set. In other words, column iCol may be required if the expression
7059 ** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to
7060 ** non-zero.
7061 **
7062 ** The [xBestIndex] method must fill aConstraintUsage[] with information
7063 ** about what parameters to pass to xFilter.  ^If argvIndex>0 then
7064 ** the right-hand side of the corresponding aConstraint[] is evaluated
7065 ** and becomes the argvIndex-th entry in argv.  ^(If aConstraintUsage[].omit
7066 ** is true, then the constraint is assumed to be fully handled by the
7067 ** virtual table and might not be checked again by the byte code.)^ ^(The
7068 ** aConstraintUsage[].omit flag is an optimization hint. When the omit flag
7069 ** is left in its default setting of false, the constraint will always be
7070 ** checked separately in byte code.  If the omit flag is change to true, then
7071 ** the constraint may or may not be checked in byte code.  In other words,
7072 ** when the omit flag is true there is no guarantee that the constraint will
7073 ** not be checked again using byte code.)^
7074 **
7075 ** ^The idxNum and idxPtr values are recorded and passed into the
7076 ** [xFilter] method.
7077 ** ^[sqlite3_free()] is used to free idxPtr if and only if
7078 ** needToFreeIdxPtr is true.
7079 **
7080 ** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
7081 ** the correct order to satisfy the ORDER BY clause so that no separate
7082 ** sorting step is required.
7083 **
7084 ** ^The estimatedCost value is an estimate of the cost of a particular
7085 ** strategy. A cost of N indicates that the cost of the strategy is similar
7086 ** to a linear scan of an SQLite table with N rows. A cost of log(N)
7087 ** indicates that the expense of the operation is similar to that of a
7088 ** binary search on a unique indexed field of an SQLite table with N rows.
7089 **
7090 ** ^The estimatedRows value is an estimate of the number of rows that
7091 ** will be returned by the strategy.
7092 **
7093 ** The xBestIndex method may optionally populate the idxFlags field with a
7094 ** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag -
7095 ** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite
7096 ** assumes that the strategy may visit at most one row.
7097 **
7098 ** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then
7099 ** SQLite also assumes that if a call to the xUpdate() method is made as
7100 ** part of the same statement to delete or update a virtual table row and the
7101 ** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback
7102 ** any database changes. In other words, if the xUpdate() returns
7103 ** SQLITE_CONSTRAINT, the database contents must be exactly as they were
7104 ** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not
7105 ** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by
7106 ** the xUpdate method are automatically rolled back by SQLite.
7107 **
7108 ** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info
7109 ** structure for SQLite [version 3.8.2] ([dateof:3.8.2]).
7110 ** If a virtual table extension is
7111 ** used with an SQLite version earlier than 3.8.2, the results of attempting
7112 ** to read or write the estimatedRows field are undefined (but are likely
7113 ** to include crashing the application). The estimatedRows field should
7114 ** therefore only be used if [sqlite3_libversion_number()] returns a
7115 ** value greater than or equal to 3008002. Similarly, the idxFlags field
7116 ** was added for [version 3.9.0] ([dateof:3.9.0]).
7117 ** It may therefore only be used if
7118 ** sqlite3_libversion_number() returns a value greater than or equal to
7119 ** 3009000.
7120 */
7121 struct sqlite3_index_info {
7122   /* Inputs */
7123   int nConstraint;           /* Number of entries in aConstraint */
7124   struct sqlite3_index_constraint {
7125      int iColumn;              /* Column constrained.  -1 for ROWID */
7126      unsigned char op;         /* Constraint operator */
7127      unsigned char usable;     /* True if this constraint is usable */
7128      int iTermOffset;          /* Used internally - xBestIndex should ignore */
7129   } *aConstraint;            /* Table of WHERE clause constraints */
7130   int nOrderBy;              /* Number of terms in the ORDER BY clause */
7131   struct sqlite3_index_orderby {
7132      int iColumn;              /* Column number */
7133      unsigned char desc;       /* True for DESC.  False for ASC. */
7134   } *aOrderBy;               /* The ORDER BY clause */
7135   /* Outputs */
7136   struct sqlite3_index_constraint_usage {
7137     int argvIndex;           /* if >0, constraint is part of argv to xFilter */
7138     unsigned char omit;      /* Do not code a test for this constraint */
7139   } *aConstraintUsage;
7140   int idxNum;                /* Number used to identify the index */
7141   char *idxStr;              /* String, possibly obtained from sqlite3_malloc */
7142   int needToFreeIdxStr;      /* Free idxStr using sqlite3_free() if true */
7143   int orderByConsumed;       /* True if output is already ordered */
7144   double estimatedCost;           /* Estimated cost of using this index */
7145   /* Fields below are only available in SQLite 3.8.2 and later */
7146   sqlite3_int64 estimatedRows;    /* Estimated number of rows returned */
7147   /* Fields below are only available in SQLite 3.9.0 and later */
7148   int idxFlags;              /* Mask of SQLITE_INDEX_SCAN_* flags */
7149   /* Fields below are only available in SQLite 3.10.0 and later */
7150   sqlite3_uint64 colUsed;    /* Input: Mask of columns used by statement */
7151 };
7152 
7153 /*
7154 ** CAPI3REF: Virtual Table Scan Flags
7155 **
7156 ** Virtual table implementations are allowed to set the
7157 ** [sqlite3_index_info].idxFlags field to some combination of
7158 ** these bits.
7159 */
7160 #define SQLITE_INDEX_SCAN_UNIQUE      1     /* Scan visits at most 1 row */
7161 
7162 /*
7163 ** CAPI3REF: Virtual Table Constraint Operator Codes
7164 **
7165 ** These macros define the allowed values for the
7166 ** [sqlite3_index_info].aConstraint[].op field.  Each value represents
7167 ** an operator that is part of a constraint term in the WHERE clause of
7168 ** a query that uses a [virtual table].
7169 **
7170 ** ^The left-hand operand of the operator is given by the corresponding
7171 ** aConstraint[].iColumn field.  ^An iColumn of -1 indicates the left-hand
7172 ** operand is the rowid.
7173 ** The SQLITE_INDEX_CONSTRAINT_LIMIT and SQLITE_INDEX_CONSTRAINT_OFFSET
7174 ** operators have no left-hand operand, and so for those operators the
7175 ** corresponding aConstraint[].iColumn is meaningless and should not be
7176 ** used.
7177 **
7178 ** All operator values from SQLITE_INDEX_CONSTRAINT_FUNCTION through
7179 ** value 255 are reserved to represent functions that are overloaded
7180 ** by the [xFindFunction|xFindFunction method] of the virtual table
7181 ** implementation.
7182 **
7183 ** The right-hand operands for each constraint might be accessible using
7184 ** the [sqlite3_vtab_rhs_value()] interface.  Usually the right-hand
7185 ** operand is only available if it appears as a single constant literal
7186 ** in the input SQL.  If the right-hand operand is another column or an
7187 ** expression (even a constant expression) or a parameter, then the
7188 ** sqlite3_vtab_rhs_value() probably will not be able to extract it.
7189 ** ^The SQLITE_INDEX_CONSTRAINT_ISNULL and
7190 ** SQLITE_INDEX_CONSTRAINT_ISNOTNULL operators have no right-hand operand
7191 ** and hence calls to sqlite3_vtab_rhs_value() for those operators will
7192 ** always return SQLITE_NOTFOUND.
7193 **
7194 ** The collating sequence to be used for comparison can be found using
7195 ** the [sqlite3_vtab_collation()] interface.  For most real-world virtual
7196 ** tables, the collating sequence of constraints does not matter (for example
7197 ** because the constraints are numeric) and so the sqlite3_vtab_collation()
7198 ** interface is no commonly needed.
7199 */
7200 #define SQLITE_INDEX_CONSTRAINT_EQ          2
7201 #define SQLITE_INDEX_CONSTRAINT_GT          4
7202 #define SQLITE_INDEX_CONSTRAINT_LE          8
7203 #define SQLITE_INDEX_CONSTRAINT_LT         16
7204 #define SQLITE_INDEX_CONSTRAINT_GE         32
7205 #define SQLITE_INDEX_CONSTRAINT_MATCH      64
7206 #define SQLITE_INDEX_CONSTRAINT_LIKE       65
7207 #define SQLITE_INDEX_CONSTRAINT_GLOB       66
7208 #define SQLITE_INDEX_CONSTRAINT_REGEXP     67
7209 #define SQLITE_INDEX_CONSTRAINT_NE         68
7210 #define SQLITE_INDEX_CONSTRAINT_ISNOT      69
7211 #define SQLITE_INDEX_CONSTRAINT_ISNOTNULL  70
7212 #define SQLITE_INDEX_CONSTRAINT_ISNULL     71
7213 #define SQLITE_INDEX_CONSTRAINT_IS         72
7214 #define SQLITE_INDEX_CONSTRAINT_LIMIT      73
7215 #define SQLITE_INDEX_CONSTRAINT_OFFSET     74
7216 #define SQLITE_INDEX_CONSTRAINT_FUNCTION  150
7217 
7218 /*
7219 ** CAPI3REF: Register A Virtual Table Implementation
7220 ** METHOD: sqlite3
7221 **
7222 ** ^These routines are used to register a new [virtual table module] name.
7223 ** ^Module names must be registered before
7224 ** creating a new [virtual table] using the module and before using a
7225 ** preexisting [virtual table] for the module.
7226 **
7227 ** ^The module name is registered on the [database connection] specified
7228 ** by the first parameter.  ^The name of the module is given by the
7229 ** second parameter.  ^The third parameter is a pointer to
7230 ** the implementation of the [virtual table module].   ^The fourth
7231 ** parameter is an arbitrary client data pointer that is passed through
7232 ** into the [xCreate] and [xConnect] methods of the virtual table module
7233 ** when a new virtual table is be being created or reinitialized.
7234 **
7235 ** ^The sqlite3_create_module_v2() interface has a fifth parameter which
7236 ** is a pointer to a destructor for the pClientData.  ^SQLite will
7237 ** invoke the destructor function (if it is not NULL) when SQLite
7238 ** no longer needs the pClientData pointer.  ^The destructor will also
7239 ** be invoked if the call to sqlite3_create_module_v2() fails.
7240 ** ^The sqlite3_create_module()
7241 ** interface is equivalent to sqlite3_create_module_v2() with a NULL
7242 ** destructor.
7243 **
7244 ** ^If the third parameter (the pointer to the sqlite3_module object) is
7245 ** NULL then no new module is created and any existing modules with the
7246 ** same name are dropped.
7247 **
7248 ** See also: [sqlite3_drop_modules()]
7249 */
7250 SQLITE_API int sqlite3_create_module(
7251   sqlite3 *db,               /* SQLite connection to register module with */
7252   const char *zName,         /* Name of the module */
7253   const sqlite3_module *p,   /* Methods for the module */
7254   void *pClientData          /* Client data for xCreate/xConnect */
7255 );
7256 SQLITE_API int sqlite3_create_module_v2(
7257   sqlite3 *db,               /* SQLite connection to register module with */
7258   const char *zName,         /* Name of the module */
7259   const sqlite3_module *p,   /* Methods for the module */
7260   void *pClientData,         /* Client data for xCreate/xConnect */
7261   void(*xDestroy)(void*)     /* Module destructor function */
7262 );
7263 
7264 /*
7265 ** CAPI3REF: Remove Unnecessary Virtual Table Implementations
7266 ** METHOD: sqlite3
7267 **
7268 ** ^The sqlite3_drop_modules(D,L) interface removes all virtual
7269 ** table modules from database connection D except those named on list L.
7270 ** The L parameter must be either NULL or a pointer to an array of pointers
7271 ** to strings where the array is terminated by a single NULL pointer.
7272 ** ^If the L parameter is NULL, then all virtual table modules are removed.
7273 **
7274 ** See also: [sqlite3_create_module()]
7275 */
7276 SQLITE_API int sqlite3_drop_modules(
7277   sqlite3 *db,                /* Remove modules from this connection */
7278   const char **azKeep         /* Except, do not remove the ones named here */
7279 );
7280 
7281 /*
7282 ** CAPI3REF: Virtual Table Instance Object
7283 ** KEYWORDS: sqlite3_vtab
7284 **
7285 ** Every [virtual table module] implementation uses a subclass
7286 ** of this object to describe a particular instance
7287 ** of the [virtual table].  Each subclass will
7288 ** be tailored to the specific needs of the module implementation.
7289 ** The purpose of this superclass is to define certain fields that are
7290 ** common to all module implementations.
7291 **
7292 ** ^Virtual tables methods can set an error message by assigning a
7293 ** string obtained from [sqlite3_mprintf()] to zErrMsg.  The method should
7294 ** take care that any prior string is freed by a call to [sqlite3_free()]
7295 ** prior to assigning a new string to zErrMsg.  ^After the error message
7296 ** is delivered up to the client application, the string will be automatically
7297 ** freed by sqlite3_free() and the zErrMsg field will be zeroed.
7298 */
7299 struct sqlite3_vtab {
7300   const sqlite3_module *pModule;  /* The module for this virtual table */
7301   int nRef;                       /* Number of open cursors */
7302   char *zErrMsg;                  /* Error message from sqlite3_mprintf() */
7303   /* Virtual table implementations will typically add additional fields */
7304 };
7305 
7306 /*
7307 ** CAPI3REF: Virtual Table Cursor Object
7308 ** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
7309 **
7310 ** Every [virtual table module] implementation uses a subclass of the
7311 ** following structure to describe cursors that point into the
7312 ** [virtual table] and are used
7313 ** to loop through the virtual table.  Cursors are created using the
7314 ** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
7315 ** by the [sqlite3_module.xClose | xClose] method.  Cursors are used
7316 ** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
7317 ** of the module.  Each module implementation will define
7318 ** the content of a cursor structure to suit its own needs.
7319 **
7320 ** This superclass exists in order to define fields of the cursor that
7321 ** are common to all implementations.
7322 */
7323 struct sqlite3_vtab_cursor {
7324   sqlite3_vtab *pVtab;      /* Virtual table of this cursor */
7325   /* Virtual table implementations will typically add additional fields */
7326 };
7327 
7328 /*
7329 ** CAPI3REF: Declare The Schema Of A Virtual Table
7330 **
7331 ** ^The [xCreate] and [xConnect] methods of a
7332 ** [virtual table module] call this interface
7333 ** to declare the format (the names and datatypes of the columns) of
7334 ** the virtual tables they implement.
7335 */
7336 SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
7337 
7338 /*
7339 ** CAPI3REF: Overload A Function For A Virtual Table
7340 ** METHOD: sqlite3
7341 **
7342 ** ^(Virtual tables can provide alternative implementations of functions
7343 ** using the [xFindFunction] method of the [virtual table module].
7344 ** But global versions of those functions
7345 ** must exist in order to be overloaded.)^
7346 **
7347 ** ^(This API makes sure a global version of a function with a particular
7348 ** name and number of parameters exists.  If no such function exists
7349 ** before this API is called, a new function is created.)^  ^The implementation
7350 ** of the new function always causes an exception to be thrown.  So
7351 ** the new function is not good for anything by itself.  Its only
7352 ** purpose is to be a placeholder function that can be overloaded
7353 ** by a [virtual table].
7354 */
7355 SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
7356 
7357 /*
7358 ** The interface to the virtual-table mechanism defined above (back up
7359 ** to a comment remarkably similar to this one) is currently considered
7360 ** to be experimental.  The interface might change in incompatible ways.
7361 ** If this is a problem for you, do not use the interface at this time.
7362 **
7363 ** When the virtual-table mechanism stabilizes, we will declare the
7364 ** interface fixed, support it indefinitely, and remove this comment.
7365 */
7366 
7367 /*
7368 ** CAPI3REF: A Handle To An Open BLOB
7369 ** KEYWORDS: {BLOB handle} {BLOB handles}
7370 **
7371 ** An instance of this object represents an open BLOB on which
7372 ** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
7373 ** ^Objects of this type are created by [sqlite3_blob_open()]
7374 ** and destroyed by [sqlite3_blob_close()].
7375 ** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
7376 ** can be used to read or write small subsections of the BLOB.
7377 ** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
7378 */
7379 typedef struct sqlite3_blob sqlite3_blob;
7380 
7381 /*
7382 ** CAPI3REF: Open A BLOB For Incremental I/O
7383 ** METHOD: sqlite3
7384 ** CONSTRUCTOR: sqlite3_blob
7385 **
7386 ** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
7387 ** in row iRow, column zColumn, table zTable in database zDb;
7388 ** in other words, the same BLOB that would be selected by:
7389 **
7390 ** <pre>
7391 **     SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
7392 ** </pre>)^
7393 **
7394 ** ^(Parameter zDb is not the filename that contains the database, but
7395 ** rather the symbolic name of the database. For attached databases, this is
7396 ** the name that appears after the AS keyword in the [ATTACH] statement.
7397 ** For the main database file, the database name is "main". For TEMP
7398 ** tables, the database name is "temp".)^
7399 **
7400 ** ^If the flags parameter is non-zero, then the BLOB is opened for read
7401 ** and write access. ^If the flags parameter is zero, the BLOB is opened for
7402 ** read-only access.
7403 **
7404 ** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored
7405 ** in *ppBlob. Otherwise an [error code] is returned and, unless the error
7406 ** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided
7407 ** the API is not misused, it is always safe to call [sqlite3_blob_close()]
7408 ** on *ppBlob after this function it returns.
7409 **
7410 ** This function fails with SQLITE_ERROR if any of the following are true:
7411 ** <ul>
7412 **   <li> ^(Database zDb does not exist)^,
7413 **   <li> ^(Table zTable does not exist within database zDb)^,
7414 **   <li> ^(Table zTable is a WITHOUT ROWID table)^,
7415 **   <li> ^(Column zColumn does not exist)^,
7416 **   <li> ^(Row iRow is not present in the table)^,
7417 **   <li> ^(The specified column of row iRow contains a value that is not
7418 **         a TEXT or BLOB value)^,
7419 **   <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE
7420 **         constraint and the blob is being opened for read/write access)^,
7421 **   <li> ^([foreign key constraints | Foreign key constraints] are enabled,
7422 **         column zColumn is part of a [child key] definition and the blob is
7423 **         being opened for read/write access)^.
7424 ** </ul>
7425 **
7426 ** ^Unless it returns SQLITE_MISUSE, this function sets the
7427 ** [database connection] error code and message accessible via
7428 ** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
7429 **
7430 ** A BLOB referenced by sqlite3_blob_open() may be read using the
7431 ** [sqlite3_blob_read()] interface and modified by using
7432 ** [sqlite3_blob_write()].  The [BLOB handle] can be moved to a
7433 ** different row of the same table using the [sqlite3_blob_reopen()]
7434 ** interface.  However, the column, table, or database of a [BLOB handle]
7435 ** cannot be changed after the [BLOB handle] is opened.
7436 **
7437 ** ^(If the row that a BLOB handle points to is modified by an
7438 ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
7439 ** then the BLOB handle is marked as "expired".
7440 ** This is true if any column of the row is changed, even a column
7441 ** other than the one the BLOB handle is open on.)^
7442 ** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
7443 ** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
7444 ** ^(Changes written into a BLOB prior to the BLOB expiring are not
7445 ** rolled back by the expiration of the BLOB.  Such changes will eventually
7446 ** commit if the transaction continues to completion.)^
7447 **
7448 ** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
7449 ** the opened blob.  ^The size of a blob may not be changed by this
7450 ** interface.  Use the [UPDATE] SQL command to change the size of a
7451 ** blob.
7452 **
7453 ** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
7454 ** and the built-in [zeroblob] SQL function may be used to create a
7455 ** zero-filled blob to read or write using the incremental-blob interface.
7456 **
7457 ** To avoid a resource leak, every open [BLOB handle] should eventually
7458 ** be released by a call to [sqlite3_blob_close()].
7459 **
7460 ** See also: [sqlite3_blob_close()],
7461 ** [sqlite3_blob_reopen()], [sqlite3_blob_read()],
7462 ** [sqlite3_blob_bytes()], [sqlite3_blob_write()].
7463 */
7464 SQLITE_API int sqlite3_blob_open(
7465   sqlite3*,
7466   const char *zDb,
7467   const char *zTable,
7468   const char *zColumn,
7469   sqlite3_int64 iRow,
7470   int flags,
7471   sqlite3_blob **ppBlob
7472 );
7473 
7474 /*
7475 ** CAPI3REF: Move a BLOB Handle to a New Row
7476 ** METHOD: sqlite3_blob
7477 **
7478 ** ^This function is used to move an existing [BLOB handle] so that it points
7479 ** to a different row of the same database table. ^The new row is identified
7480 ** by the rowid value passed as the second argument. Only the row can be
7481 ** changed. ^The database, table and column on which the blob handle is open
7482 ** remain the same. Moving an existing [BLOB handle] to a new row is
7483 ** faster than closing the existing handle and opening a new one.
7484 **
7485 ** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
7486 ** it must exist and there must be either a blob or text value stored in
7487 ** the nominated column.)^ ^If the new row is not present in the table, or if
7488 ** it does not contain a blob or text value, or if another error occurs, an
7489 ** SQLite error code is returned and the blob handle is considered aborted.
7490 ** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
7491 ** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
7492 ** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
7493 ** always returns zero.
7494 **
7495 ** ^This function sets the database handle error code and message.
7496 */
7497 SQLITE_API int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
7498 
7499 /*
7500 ** CAPI3REF: Close A BLOB Handle
7501 ** DESTRUCTOR: sqlite3_blob
7502 **
7503 ** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed
7504 ** unconditionally.  Even if this routine returns an error code, the
7505 ** handle is still closed.)^
7506 **
7507 ** ^If the blob handle being closed was opened for read-write access, and if
7508 ** the database is in auto-commit mode and there are no other open read-write
7509 ** blob handles or active write statements, the current transaction is
7510 ** committed. ^If an error occurs while committing the transaction, an error
7511 ** code is returned and the transaction rolled back.
7512 **
7513 ** Calling this function with an argument that is not a NULL pointer or an
7514 ** open blob handle results in undefined behaviour. ^Calling this routine
7515 ** with a null pointer (such as would be returned by a failed call to
7516 ** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function
7517 ** is passed a valid open blob handle, the values returned by the
7518 ** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning.
7519 */
7520 SQLITE_API int sqlite3_blob_close(sqlite3_blob *);
7521 
7522 /*
7523 ** CAPI3REF: Return The Size Of An Open BLOB
7524 ** METHOD: sqlite3_blob
7525 **
7526 ** ^Returns the size in bytes of the BLOB accessible via the
7527 ** successfully opened [BLOB handle] in its only argument.  ^The
7528 ** incremental blob I/O routines can only read or overwriting existing
7529 ** blob content; they cannot change the size of a blob.
7530 **
7531 ** This routine only works on a [BLOB handle] which has been created
7532 ** by a prior successful call to [sqlite3_blob_open()] and which has not
7533 ** been closed by [sqlite3_blob_close()].  Passing any other pointer in
7534 ** to this routine results in undefined and probably undesirable behavior.
7535 */
7536 SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *);
7537 
7538 /*
7539 ** CAPI3REF: Read Data From A BLOB Incrementally
7540 ** METHOD: sqlite3_blob
7541 **
7542 ** ^(This function is used to read data from an open [BLOB handle] into a
7543 ** caller-supplied buffer. N bytes of data are copied into buffer Z
7544 ** from the open BLOB, starting at offset iOffset.)^
7545 **
7546 ** ^If offset iOffset is less than N bytes from the end of the BLOB,
7547 ** [SQLITE_ERROR] is returned and no data is read.  ^If N or iOffset is
7548 ** less than zero, [SQLITE_ERROR] is returned and no data is read.
7549 ** ^The size of the blob (and hence the maximum value of N+iOffset)
7550 ** can be determined using the [sqlite3_blob_bytes()] interface.
7551 **
7552 ** ^An attempt to read from an expired [BLOB handle] fails with an
7553 ** error code of [SQLITE_ABORT].
7554 **
7555 ** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
7556 ** Otherwise, an [error code] or an [extended error code] is returned.)^
7557 **
7558 ** This routine only works on a [BLOB handle] which has been created
7559 ** by a prior successful call to [sqlite3_blob_open()] and which has not
7560 ** been closed by [sqlite3_blob_close()].  Passing any other pointer in
7561 ** to this routine results in undefined and probably undesirable behavior.
7562 **
7563 ** See also: [sqlite3_blob_write()].
7564 */
7565 SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
7566 
7567 /*
7568 ** CAPI3REF: Write Data Into A BLOB Incrementally
7569 ** METHOD: sqlite3_blob
7570 **
7571 ** ^(This function is used to write data into an open [BLOB handle] from a
7572 ** caller-supplied buffer. N bytes of data are copied from the buffer Z
7573 ** into the open BLOB, starting at offset iOffset.)^
7574 **
7575 ** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
7576 ** Otherwise, an  [error code] or an [extended error code] is returned.)^
7577 ** ^Unless SQLITE_MISUSE is returned, this function sets the
7578 ** [database connection] error code and message accessible via
7579 ** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
7580 **
7581 ** ^If the [BLOB handle] passed as the first argument was not opened for
7582 ** writing (the flags parameter to [sqlite3_blob_open()] was zero),
7583 ** this function returns [SQLITE_READONLY].
7584 **
7585 ** This function may only modify the contents of the BLOB; it is
7586 ** not possible to increase the size of a BLOB using this API.
7587 ** ^If offset iOffset is less than N bytes from the end of the BLOB,
7588 ** [SQLITE_ERROR] is returned and no data is written. The size of the
7589 ** BLOB (and hence the maximum value of N+iOffset) can be determined
7590 ** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less
7591 ** than zero [SQLITE_ERROR] is returned and no data is written.
7592 **
7593 ** ^An attempt to write to an expired [BLOB handle] fails with an
7594 ** error code of [SQLITE_ABORT].  ^Writes to the BLOB that occurred
7595 ** before the [BLOB handle] expired are not rolled back by the
7596 ** expiration of the handle, though of course those changes might
7597 ** have been overwritten by the statement that expired the BLOB handle
7598 ** or by other independent statements.
7599 **
7600 ** This routine only works on a [BLOB handle] which has been created
7601 ** by a prior successful call to [sqlite3_blob_open()] and which has not
7602 ** been closed by [sqlite3_blob_close()].  Passing any other pointer in
7603 ** to this routine results in undefined and probably undesirable behavior.
7604 **
7605 ** See also: [sqlite3_blob_read()].
7606 */
7607 SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
7608 
7609 /*
7610 ** CAPI3REF: Virtual File System Objects
7611 **
7612 ** A virtual filesystem (VFS) is an [sqlite3_vfs] object
7613 ** that SQLite uses to interact
7614 ** with the underlying operating system.  Most SQLite builds come with a
7615 ** single default VFS that is appropriate for the host computer.
7616 ** New VFSes can be registered and existing VFSes can be unregistered.
7617 ** The following interfaces are provided.
7618 **
7619 ** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
7620 ** ^Names are case sensitive.
7621 ** ^Names are zero-terminated UTF-8 strings.
7622 ** ^If there is no match, a NULL pointer is returned.
7623 ** ^If zVfsName is NULL then the default VFS is returned.
7624 **
7625 ** ^New VFSes are registered with sqlite3_vfs_register().
7626 ** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
7627 ** ^The same VFS can be registered multiple times without injury.
7628 ** ^To make an existing VFS into the default VFS, register it again
7629 ** with the makeDflt flag set.  If two different VFSes with the
7630 ** same name are registered, the behavior is undefined.  If a
7631 ** VFS is registered with a name that is NULL or an empty string,
7632 ** then the behavior is undefined.
7633 **
7634 ** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
7635 ** ^(If the default VFS is unregistered, another VFS is chosen as
7636 ** the default.  The choice for the new VFS is arbitrary.)^
7637 */
7638 SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
7639 SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
7640 SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*);
7641 
7642 /*
7643 ** CAPI3REF: Mutexes
7644 **
7645 ** The SQLite core uses these routines for thread
7646 ** synchronization. Though they are intended for internal
7647 ** use by SQLite, code that links against SQLite is
7648 ** permitted to use any of these routines.
7649 **
7650 ** The SQLite source code contains multiple implementations
7651 ** of these mutex routines.  An appropriate implementation
7652 ** is selected automatically at compile-time.  The following
7653 ** implementations are available in the SQLite core:
7654 **
7655 ** <ul>
7656 ** <li>   SQLITE_MUTEX_PTHREADS
7657 ** <li>   SQLITE_MUTEX_W32
7658 ** <li>   SQLITE_MUTEX_NOOP
7659 ** </ul>
7660 **
7661 ** The SQLITE_MUTEX_NOOP implementation is a set of routines
7662 ** that does no real locking and is appropriate for use in
7663 ** a single-threaded application.  The SQLITE_MUTEX_PTHREADS and
7664 ** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
7665 ** and Windows.
7666 **
7667 ** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
7668 ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
7669 ** implementation is included with the library. In this case the
7670 ** application must supply a custom mutex implementation using the
7671 ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
7672 ** before calling sqlite3_initialize() or any other public sqlite3_
7673 ** function that calls sqlite3_initialize().
7674 **
7675 ** ^The sqlite3_mutex_alloc() routine allocates a new
7676 ** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc()
7677 ** routine returns NULL if it is unable to allocate the requested
7678 ** mutex.  The argument to sqlite3_mutex_alloc() must one of these
7679 ** integer constants:
7680 **
7681 ** <ul>
7682 ** <li>  SQLITE_MUTEX_FAST
7683 ** <li>  SQLITE_MUTEX_RECURSIVE
7684 ** <li>  SQLITE_MUTEX_STATIC_MAIN
7685 ** <li>  SQLITE_MUTEX_STATIC_MEM
7686 ** <li>  SQLITE_MUTEX_STATIC_OPEN
7687 ** <li>  SQLITE_MUTEX_STATIC_PRNG
7688 ** <li>  SQLITE_MUTEX_STATIC_LRU
7689 ** <li>  SQLITE_MUTEX_STATIC_PMEM
7690 ** <li>  SQLITE_MUTEX_STATIC_APP1
7691 ** <li>  SQLITE_MUTEX_STATIC_APP2
7692 ** <li>  SQLITE_MUTEX_STATIC_APP3
7693 ** <li>  SQLITE_MUTEX_STATIC_VFS1
7694 ** <li>  SQLITE_MUTEX_STATIC_VFS2
7695 ** <li>  SQLITE_MUTEX_STATIC_VFS3
7696 ** </ul>
7697 **
7698 ** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
7699 ** cause sqlite3_mutex_alloc() to create
7700 ** a new mutex.  ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
7701 ** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
7702 ** The mutex implementation does not need to make a distinction
7703 ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
7704 ** not want to.  SQLite will only request a recursive mutex in
7705 ** cases where it really needs one.  If a faster non-recursive mutex
7706 ** implementation is available on the host platform, the mutex subsystem
7707 ** might return such a mutex in response to SQLITE_MUTEX_FAST.
7708 **
7709 ** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
7710 ** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
7711 ** a pointer to a static preexisting mutex.  ^Nine static mutexes are
7712 ** used by the current version of SQLite.  Future versions of SQLite
7713 ** may add additional static mutexes.  Static mutexes are for internal
7714 ** use by SQLite only.  Applications that use SQLite mutexes should
7715 ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
7716 ** SQLITE_MUTEX_RECURSIVE.
7717 **
7718 ** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
7719 ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
7720 ** returns a different mutex on every call.  ^For the static
7721 ** mutex types, the same mutex is returned on every call that has
7722 ** the same type number.
7723 **
7724 ** ^The sqlite3_mutex_free() routine deallocates a previously
7725 ** allocated dynamic mutex.  Attempting to deallocate a static
7726 ** mutex results in undefined behavior.
7727 **
7728 ** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
7729 ** to enter a mutex.  ^If another thread is already within the mutex,
7730 ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
7731 ** SQLITE_BUSY.  ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
7732 ** upon successful entry.  ^(Mutexes created using
7733 ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
7734 ** In such cases, the
7735 ** mutex must be exited an equal number of times before another thread
7736 ** can enter.)^  If the same thread tries to enter any mutex other
7737 ** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined.
7738 **
7739 ** ^(Some systems (for example, Windows 95) do not support the operation
7740 ** implemented by sqlite3_mutex_try().  On those systems, sqlite3_mutex_try()
7741 ** will always return SQLITE_BUSY. The SQLite core only ever uses
7742 ** sqlite3_mutex_try() as an optimization so this is acceptable
7743 ** behavior.)^
7744 **
7745 ** ^The sqlite3_mutex_leave() routine exits a mutex that was
7746 ** previously entered by the same thread.   The behavior
7747 ** is undefined if the mutex is not currently entered by the
7748 ** calling thread or is not currently allocated.
7749 **
7750 ** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
7751 ** sqlite3_mutex_leave() is a NULL pointer, then all three routines
7752 ** behave as no-ops.
7753 **
7754 ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
7755 */
7756 SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int);
7757 SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*);
7758 SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*);
7759 SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*);
7760 SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*);
7761 
7762 /*
7763 ** CAPI3REF: Mutex Methods Object
7764 **
7765 ** An instance of this structure defines the low-level routines
7766 ** used to allocate and use mutexes.
7767 **
7768 ** Usually, the default mutex implementations provided by SQLite are
7769 ** sufficient, however the application has the option of substituting a custom
7770 ** implementation for specialized deployments or systems for which SQLite
7771 ** does not provide a suitable implementation. In this case, the application
7772 ** creates and populates an instance of this structure to pass
7773 ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
7774 ** Additionally, an instance of this structure can be used as an
7775 ** output variable when querying the system for the current mutex
7776 ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
7777 **
7778 ** ^The xMutexInit method defined by this structure is invoked as
7779 ** part of system initialization by the sqlite3_initialize() function.
7780 ** ^The xMutexInit routine is called by SQLite exactly once for each
7781 ** effective call to [sqlite3_initialize()].
7782 **
7783 ** ^The xMutexEnd method defined by this structure is invoked as
7784 ** part of system shutdown by the sqlite3_shutdown() function. The
7785 ** implementation of this method is expected to release all outstanding
7786 ** resources obtained by the mutex methods implementation, especially
7787 ** those obtained by the xMutexInit method.  ^The xMutexEnd()
7788 ** interface is invoked exactly once for each call to [sqlite3_shutdown()].
7789 **
7790 ** ^(The remaining seven methods defined by this structure (xMutexAlloc,
7791 ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
7792 ** xMutexNotheld) implement the following interfaces (respectively):
7793 **
7794 ** <ul>
7795 **   <li>  [sqlite3_mutex_alloc()] </li>
7796 **   <li>  [sqlite3_mutex_free()] </li>
7797 **   <li>  [sqlite3_mutex_enter()] </li>
7798 **   <li>  [sqlite3_mutex_try()] </li>
7799 **   <li>  [sqlite3_mutex_leave()] </li>
7800 **   <li>  [sqlite3_mutex_held()] </li>
7801 **   <li>  [sqlite3_mutex_notheld()] </li>
7802 ** </ul>)^
7803 **
7804 ** The only difference is that the public sqlite3_XXX functions enumerated
7805 ** above silently ignore any invocations that pass a NULL pointer instead
7806 ** of a valid mutex handle. The implementations of the methods defined
7807 ** by this structure are not required to handle this case. The results
7808 ** of passing a NULL pointer instead of a valid mutex handle are undefined
7809 ** (i.e. it is acceptable to provide an implementation that segfaults if
7810 ** it is passed a NULL pointer).
7811 **
7812 ** The xMutexInit() method must be threadsafe.  It must be harmless to
7813 ** invoke xMutexInit() multiple times within the same process and without
7814 ** intervening calls to xMutexEnd().  Second and subsequent calls to
7815 ** xMutexInit() must be no-ops.
7816 **
7817 ** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
7818 ** and its associates).  Similarly, xMutexAlloc() must not use SQLite memory
7819 ** allocation for a static mutex.  ^However xMutexAlloc() may use SQLite
7820 ** memory allocation for a fast or recursive mutex.
7821 **
7822 ** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
7823 ** called, but only if the prior call to xMutexInit returned SQLITE_OK.
7824 ** If xMutexInit fails in any way, it is expected to clean up after itself
7825 ** prior to returning.
7826 */
7827 typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
7828 struct sqlite3_mutex_methods {
7829   int (*xMutexInit)(void);
7830   int (*xMutexEnd)(void);
7831   sqlite3_mutex *(*xMutexAlloc)(int);
7832   void (*xMutexFree)(sqlite3_mutex *);
7833   void (*xMutexEnter)(sqlite3_mutex *);
7834   int (*xMutexTry)(sqlite3_mutex *);
7835   void (*xMutexLeave)(sqlite3_mutex *);
7836   int (*xMutexHeld)(sqlite3_mutex *);
7837   int (*xMutexNotheld)(sqlite3_mutex *);
7838 };
7839 
7840 /*
7841 ** CAPI3REF: Mutex Verification Routines
7842 **
7843 ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
7844 ** are intended for use inside assert() statements.  The SQLite core
7845 ** never uses these routines except inside an assert() and applications
7846 ** are advised to follow the lead of the core.  The SQLite core only
7847 ** provides implementations for these routines when it is compiled
7848 ** with the SQLITE_DEBUG flag.  External mutex implementations
7849 ** are only required to provide these routines if SQLITE_DEBUG is
7850 ** defined and if NDEBUG is not defined.
7851 **
7852 ** These routines should return true if the mutex in their argument
7853 ** is held or not held, respectively, by the calling thread.
7854 **
7855 ** The implementation is not required to provide versions of these
7856 ** routines that actually work. If the implementation does not provide working
7857 ** versions of these routines, it should at least provide stubs that always
7858 ** return true so that one does not get spurious assertion failures.
7859 **
7860 ** If the argument to sqlite3_mutex_held() is a NULL pointer then
7861 ** the routine should return 1.   This seems counter-intuitive since
7862 ** clearly the mutex cannot be held if it does not exist.  But
7863 ** the reason the mutex does not exist is because the build is not
7864 ** using mutexes.  And we do not want the assert() containing the
7865 ** call to sqlite3_mutex_held() to fail, so a non-zero return is
7866 ** the appropriate thing to do.  The sqlite3_mutex_notheld()
7867 ** interface should also return 1 when given a NULL pointer.
7868 */
7869 #ifndef NDEBUG
7870 SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*);
7871 SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*);
7872 #endif
7873 
7874 /*
7875 ** CAPI3REF: Mutex Types
7876 **
7877 ** The [sqlite3_mutex_alloc()] interface takes a single argument
7878 ** which is one of these integer constants.
7879 **
7880 ** The set of static mutexes may change from one SQLite release to the
7881 ** next.  Applications that override the built-in mutex logic must be
7882 ** prepared to accommodate additional static mutexes.
7883 */
7884 #define SQLITE_MUTEX_FAST             0
7885 #define SQLITE_MUTEX_RECURSIVE        1
7886 #define SQLITE_MUTEX_STATIC_MAIN      2
7887 #define SQLITE_MUTEX_STATIC_MEM       3  /* sqlite3_malloc() */
7888 #define SQLITE_MUTEX_STATIC_MEM2      4  /* NOT USED */
7889 #define SQLITE_MUTEX_STATIC_OPEN      4  /* sqlite3BtreeOpen() */
7890 #define SQLITE_MUTEX_STATIC_PRNG      5  /* sqlite3_randomness() */
7891 #define SQLITE_MUTEX_STATIC_LRU       6  /* lru page list */
7892 #define SQLITE_MUTEX_STATIC_LRU2      7  /* NOT USED */
7893 #define SQLITE_MUTEX_STATIC_PMEM      7  /* sqlite3PageMalloc() */
7894 #define SQLITE_MUTEX_STATIC_APP1      8  /* For use by application */
7895 #define SQLITE_MUTEX_STATIC_APP2      9  /* For use by application */
7896 #define SQLITE_MUTEX_STATIC_APP3     10  /* For use by application */
7897 #define SQLITE_MUTEX_STATIC_VFS1     11  /* For use by built-in VFS */
7898 #define SQLITE_MUTEX_STATIC_VFS2     12  /* For use by extension VFS */
7899 #define SQLITE_MUTEX_STATIC_VFS3     13  /* For use by application VFS */
7900 
7901 /* Legacy compatibility: */
7902 #define SQLITE_MUTEX_STATIC_MASTER    2
7903 
7904 
7905 /*
7906 ** CAPI3REF: Retrieve the mutex for a database connection
7907 ** METHOD: sqlite3
7908 **
7909 ** ^This interface returns a pointer the [sqlite3_mutex] object that
7910 ** serializes access to the [database connection] given in the argument
7911 ** when the [threading mode] is Serialized.
7912 ** ^If the [threading mode] is Single-thread or Multi-thread then this
7913 ** routine returns a NULL pointer.
7914 */
7915 SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
7916 
7917 /*
7918 ** CAPI3REF: Low-Level Control Of Database Files
7919 ** METHOD: sqlite3
7920 ** KEYWORDS: {file control}
7921 **
7922 ** ^The [sqlite3_file_control()] interface makes a direct call to the
7923 ** xFileControl method for the [sqlite3_io_methods] object associated
7924 ** with a particular database identified by the second argument. ^The
7925 ** name of the database is "main" for the main database or "temp" for the
7926 ** TEMP database, or the name that appears after the AS keyword for
7927 ** databases that are added using the [ATTACH] SQL command.
7928 ** ^A NULL pointer can be used in place of "main" to refer to the
7929 ** main database file.
7930 ** ^The third and fourth parameters to this routine
7931 ** are passed directly through to the second and third parameters of
7932 ** the xFileControl method.  ^The return value of the xFileControl
7933 ** method becomes the return value of this routine.
7934 **
7935 ** A few opcodes for [sqlite3_file_control()] are handled directly
7936 ** by the SQLite core and never invoke the
7937 ** sqlite3_io_methods.xFileControl method.
7938 ** ^The [SQLITE_FCNTL_FILE_POINTER] value for the op parameter causes
7939 ** a pointer to the underlying [sqlite3_file] object to be written into
7940 ** the space pointed to by the 4th parameter.  The
7941 ** [SQLITE_FCNTL_JOURNAL_POINTER] works similarly except that it returns
7942 ** the [sqlite3_file] object associated with the journal file instead of
7943 ** the main database.  The [SQLITE_FCNTL_VFS_POINTER] opcode returns
7944 ** a pointer to the underlying [sqlite3_vfs] object for the file.
7945 ** The [SQLITE_FCNTL_DATA_VERSION] returns the data version counter
7946 ** from the pager.
7947 **
7948 ** ^If the second parameter (zDbName) does not match the name of any
7949 ** open database file, then SQLITE_ERROR is returned.  ^This error
7950 ** code is not remembered and will not be recalled by [sqlite3_errcode()]
7951 ** or [sqlite3_errmsg()].  The underlying xFileControl method might
7952 ** also return SQLITE_ERROR.  There is no way to distinguish between
7953 ** an incorrect zDbName and an SQLITE_ERROR return from the underlying
7954 ** xFileControl method.
7955 **
7956 ** See also: [file control opcodes]
7957 */
7958 SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
7959 
7960 /*
7961 ** CAPI3REF: Testing Interface
7962 **
7963 ** ^The sqlite3_test_control() interface is used to read out internal
7964 ** state of SQLite and to inject faults into SQLite for testing
7965 ** purposes.  ^The first parameter is an operation code that determines
7966 ** the number, meaning, and operation of all subsequent parameters.
7967 **
7968 ** This interface is not for use by applications.  It exists solely
7969 ** for verifying the correct operation of the SQLite library.  Depending
7970 ** on how the SQLite library is compiled, this interface might not exist.
7971 **
7972 ** The details of the operation codes, their meanings, the parameters
7973 ** they take, and what they do are all subject to change without notice.
7974 ** Unlike most of the SQLite API, this function is not guaranteed to
7975 ** operate consistently from one release to the next.
7976 */
7977 SQLITE_API int sqlite3_test_control(int op, ...);
7978 
7979 /*
7980 ** CAPI3REF: Testing Interface Operation Codes
7981 **
7982 ** These constants are the valid operation code parameters used
7983 ** as the first argument to [sqlite3_test_control()].
7984 **
7985 ** These parameters and their meanings are subject to change
7986 ** without notice.  These values are for testing purposes only.
7987 ** Applications should not use any of these parameters or the
7988 ** [sqlite3_test_control()] interface.
7989 */
7990 #define SQLITE_TESTCTRL_FIRST                    5
7991 #define SQLITE_TESTCTRL_PRNG_SAVE                5
7992 #define SQLITE_TESTCTRL_PRNG_RESTORE             6
7993 #define SQLITE_TESTCTRL_PRNG_RESET               7  /* NOT USED */
7994 #define SQLITE_TESTCTRL_BITVEC_TEST              8
7995 #define SQLITE_TESTCTRL_FAULT_INSTALL            9
7996 #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS     10
7997 #define SQLITE_TESTCTRL_PENDING_BYTE            11
7998 #define SQLITE_TESTCTRL_ASSERT                  12
7999 #define SQLITE_TESTCTRL_ALWAYS                  13
8000 #define SQLITE_TESTCTRL_RESERVE                 14  /* NOT USED */
8001 #define SQLITE_TESTCTRL_OPTIMIZATIONS           15
8002 #define SQLITE_TESTCTRL_ISKEYWORD               16  /* NOT USED */
8003 #define SQLITE_TESTCTRL_SCRATCHMALLOC           17  /* NOT USED */
8004 #define SQLITE_TESTCTRL_INTERNAL_FUNCTIONS      17
8005 #define SQLITE_TESTCTRL_LOCALTIME_FAULT         18
8006 #define SQLITE_TESTCTRL_EXPLAIN_STMT            19  /* NOT USED */
8007 #define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD    19
8008 #define SQLITE_TESTCTRL_NEVER_CORRUPT           20
8009 #define SQLITE_TESTCTRL_VDBE_COVERAGE           21
8010 #define SQLITE_TESTCTRL_BYTEORDER               22
8011 #define SQLITE_TESTCTRL_ISINIT                  23
8012 #define SQLITE_TESTCTRL_SORTER_MMAP             24
8013 #define SQLITE_TESTCTRL_IMPOSTER                25
8014 #define SQLITE_TESTCTRL_PARSER_COVERAGE         26
8015 #define SQLITE_TESTCTRL_RESULT_INTREAL          27
8016 #define SQLITE_TESTCTRL_PRNG_SEED               28
8017 #define SQLITE_TESTCTRL_EXTRA_SCHEMA_CHECKS     29
8018 #define SQLITE_TESTCTRL_SEEK_COUNT              30
8019 #define SQLITE_TESTCTRL_TRACEFLAGS              31
8020 #define SQLITE_TESTCTRL_TUNE                    32
8021 #define SQLITE_TESTCTRL_LOGEST                  33
8022 #define SQLITE_TESTCTRL_LAST                    33  /* Largest TESTCTRL */
8023 
8024 /*
8025 ** CAPI3REF: SQL Keyword Checking
8026 **
8027 ** These routines provide access to the set of SQL language keywords
8028 ** recognized by SQLite.  Applications can uses these routines to determine
8029 ** whether or not a specific identifier needs to be escaped (for example,
8030 ** by enclosing in double-quotes) so as not to confuse the parser.
8031 **
8032 ** The sqlite3_keyword_count() interface returns the number of distinct
8033 ** keywords understood by SQLite.
8034 **
8035 ** The sqlite3_keyword_name(N,Z,L) interface finds the N-th keyword and
8036 ** makes *Z point to that keyword expressed as UTF8 and writes the number
8037 ** of bytes in the keyword into *L.  The string that *Z points to is not
8038 ** zero-terminated.  The sqlite3_keyword_name(N,Z,L) routine returns
8039 ** SQLITE_OK if N is within bounds and SQLITE_ERROR if not. If either Z
8040 ** or L are NULL or invalid pointers then calls to
8041 ** sqlite3_keyword_name(N,Z,L) result in undefined behavior.
8042 **
8043 ** The sqlite3_keyword_check(Z,L) interface checks to see whether or not
8044 ** the L-byte UTF8 identifier that Z points to is a keyword, returning non-zero
8045 ** if it is and zero if not.
8046 **
8047 ** The parser used by SQLite is forgiving.  It is often possible to use
8048 ** a keyword as an identifier as long as such use does not result in a
8049 ** parsing ambiguity.  For example, the statement
8050 ** "CREATE TABLE BEGIN(REPLACE,PRAGMA,END);" is accepted by SQLite, and
8051 ** creates a new table named "BEGIN" with three columns named
8052 ** "REPLACE", "PRAGMA", and "END".  Nevertheless, best practice is to avoid
8053 ** using keywords as identifiers.  Common techniques used to avoid keyword
8054 ** name collisions include:
8055 ** <ul>
8056 ** <li> Put all identifier names inside double-quotes.  This is the official
8057 **      SQL way to escape identifier names.
8058 ** <li> Put identifier names inside &#91;...&#93;.  This is not standard SQL,
8059 **      but it is what SQL Server does and so lots of programmers use this
8060 **      technique.
8061 ** <li> Begin every identifier with the letter "Z" as no SQL keywords start
8062 **      with "Z".
8063 ** <li> Include a digit somewhere in every identifier name.
8064 ** </ul>
8065 **
8066 ** Note that the number of keywords understood by SQLite can depend on
8067 ** compile-time options.  For example, "VACUUM" is not a keyword if
8068 ** SQLite is compiled with the [-DSQLITE_OMIT_VACUUM] option.  Also,
8069 ** new keywords may be added to future releases of SQLite.
8070 */
8071 SQLITE_API int sqlite3_keyword_count(void);
8072 SQLITE_API int sqlite3_keyword_name(int,const char**,int*);
8073 SQLITE_API int sqlite3_keyword_check(const char*,int);
8074 
8075 /*
8076 ** CAPI3REF: Dynamic String Object
8077 ** KEYWORDS: {dynamic string}
8078 **
8079 ** An instance of the sqlite3_str object contains a dynamically-sized
8080 ** string under construction.
8081 **
8082 ** The lifecycle of an sqlite3_str object is as follows:
8083 ** <ol>
8084 ** <li> ^The sqlite3_str object is created using [sqlite3_str_new()].
8085 ** <li> ^Text is appended to the sqlite3_str object using various
8086 ** methods, such as [sqlite3_str_appendf()].
8087 ** <li> ^The sqlite3_str object is destroyed and the string it created
8088 ** is returned using the [sqlite3_str_finish()] interface.
8089 ** </ol>
8090 */
8091 typedef struct sqlite3_str sqlite3_str;
8092 
8093 /*
8094 ** CAPI3REF: Create A New Dynamic String Object
8095 ** CONSTRUCTOR: sqlite3_str
8096 **
8097 ** ^The [sqlite3_str_new(D)] interface allocates and initializes
8098 ** a new [sqlite3_str] object.  To avoid memory leaks, the object returned by
8099 ** [sqlite3_str_new()] must be freed by a subsequent call to
8100 ** [sqlite3_str_finish(X)].
8101 **
8102 ** ^The [sqlite3_str_new(D)] interface always returns a pointer to a
8103 ** valid [sqlite3_str] object, though in the event of an out-of-memory
8104 ** error the returned object might be a special singleton that will
8105 ** silently reject new text, always return SQLITE_NOMEM from
8106 ** [sqlite3_str_errcode()], always return 0 for
8107 ** [sqlite3_str_length()], and always return NULL from
8108 ** [sqlite3_str_finish(X)].  It is always safe to use the value
8109 ** returned by [sqlite3_str_new(D)] as the sqlite3_str parameter
8110 ** to any of the other [sqlite3_str] methods.
8111 **
8112 ** The D parameter to [sqlite3_str_new(D)] may be NULL.  If the
8113 ** D parameter in [sqlite3_str_new(D)] is not NULL, then the maximum
8114 ** length of the string contained in the [sqlite3_str] object will be
8115 ** the value set for [sqlite3_limit](D,[SQLITE_LIMIT_LENGTH]) instead
8116 ** of [SQLITE_MAX_LENGTH].
8117 */
8118 SQLITE_API sqlite3_str *sqlite3_str_new(sqlite3*);
8119 
8120 /*
8121 ** CAPI3REF: Finalize A Dynamic String
8122 ** DESTRUCTOR: sqlite3_str
8123 **
8124 ** ^The [sqlite3_str_finish(X)] interface destroys the sqlite3_str object X
8125 ** and returns a pointer to a memory buffer obtained from [sqlite3_malloc64()]
8126 ** that contains the constructed string.  The calling application should
8127 ** pass the returned value to [sqlite3_free()] to avoid a memory leak.
8128 ** ^The [sqlite3_str_finish(X)] interface may return a NULL pointer if any
8129 ** errors were encountered during construction of the string.  ^The
8130 ** [sqlite3_str_finish(X)] interface will also return a NULL pointer if the
8131 ** string in [sqlite3_str] object X is zero bytes long.
8132 */
8133 SQLITE_API char *sqlite3_str_finish(sqlite3_str*);
8134 
8135 /*
8136 ** CAPI3REF: Add Content To A Dynamic String
8137 ** METHOD: sqlite3_str
8138 **
8139 ** These interfaces add content to an sqlite3_str object previously obtained
8140 ** from [sqlite3_str_new()].
8141 **
8142 ** ^The [sqlite3_str_appendf(X,F,...)] and
8143 ** [sqlite3_str_vappendf(X,F,V)] interfaces uses the [built-in printf]
8144 ** functionality of SQLite to append formatted text onto the end of
8145 ** [sqlite3_str] object X.
8146 **
8147 ** ^The [sqlite3_str_append(X,S,N)] method appends exactly N bytes from string S
8148 ** onto the end of the [sqlite3_str] object X.  N must be non-negative.
8149 ** S must contain at least N non-zero bytes of content.  To append a
8150 ** zero-terminated string in its entirety, use the [sqlite3_str_appendall()]
8151 ** method instead.
8152 **
8153 ** ^The [sqlite3_str_appendall(X,S)] method appends the complete content of
8154 ** zero-terminated string S onto the end of [sqlite3_str] object X.
8155 **
8156 ** ^The [sqlite3_str_appendchar(X,N,C)] method appends N copies of the
8157 ** single-byte character C onto the end of [sqlite3_str] object X.
8158 ** ^This method can be used, for example, to add whitespace indentation.
8159 **
8160 ** ^The [sqlite3_str_reset(X)] method resets the string under construction
8161 ** inside [sqlite3_str] object X back to zero bytes in length.
8162 **
8163 ** These methods do not return a result code.  ^If an error occurs, that fact
8164 ** is recorded in the [sqlite3_str] object and can be recovered by a
8165 ** subsequent call to [sqlite3_str_errcode(X)].
8166 */
8167 SQLITE_API void sqlite3_str_appendf(sqlite3_str*, const char *zFormat, ...);
8168 SQLITE_API void sqlite3_str_vappendf(sqlite3_str*, const char *zFormat, va_list);
8169 SQLITE_API void sqlite3_str_append(sqlite3_str*, const char *zIn, int N);
8170 SQLITE_API void sqlite3_str_appendall(sqlite3_str*, const char *zIn);
8171 SQLITE_API void sqlite3_str_appendchar(sqlite3_str*, int N, char C);
8172 SQLITE_API void sqlite3_str_reset(sqlite3_str*);
8173 
8174 /*
8175 ** CAPI3REF: Status Of A Dynamic String
8176 ** METHOD: sqlite3_str
8177 **
8178 ** These interfaces return the current status of an [sqlite3_str] object.
8179 **
8180 ** ^If any prior errors have occurred while constructing the dynamic string
8181 ** in sqlite3_str X, then the [sqlite3_str_errcode(X)] method will return
8182 ** an appropriate error code.  ^The [sqlite3_str_errcode(X)] method returns
8183 ** [SQLITE_NOMEM] following any out-of-memory error, or
8184 ** [SQLITE_TOOBIG] if the size of the dynamic string exceeds
8185 ** [SQLITE_MAX_LENGTH], or [SQLITE_OK] if there have been no errors.
8186 **
8187 ** ^The [sqlite3_str_length(X)] method returns the current length, in bytes,
8188 ** of the dynamic string under construction in [sqlite3_str] object X.
8189 ** ^The length returned by [sqlite3_str_length(X)] does not include the
8190 ** zero-termination byte.
8191 **
8192 ** ^The [sqlite3_str_value(X)] method returns a pointer to the current
8193 ** content of the dynamic string under construction in X.  The value
8194 ** returned by [sqlite3_str_value(X)] is managed by the sqlite3_str object X
8195 ** and might be freed or altered by any subsequent method on the same
8196 ** [sqlite3_str] object.  Applications must not used the pointer returned
8197 ** [sqlite3_str_value(X)] after any subsequent method call on the same
8198 ** object.  ^Applications may change the content of the string returned
8199 ** by [sqlite3_str_value(X)] as long as they do not write into any bytes
8200 ** outside the range of 0 to [sqlite3_str_length(X)] and do not read or
8201 ** write any byte after any subsequent sqlite3_str method call.
8202 */
8203 SQLITE_API int sqlite3_str_errcode(sqlite3_str*);
8204 SQLITE_API int sqlite3_str_length(sqlite3_str*);
8205 SQLITE_API char *sqlite3_str_value(sqlite3_str*);
8206 
8207 /*
8208 ** CAPI3REF: SQLite Runtime Status
8209 **
8210 ** ^These interfaces are used to retrieve runtime status information
8211 ** about the performance of SQLite, and optionally to reset various
8212 ** highwater marks.  ^The first argument is an integer code for
8213 ** the specific parameter to measure.  ^(Recognized integer codes
8214 ** are of the form [status parameters | SQLITE_STATUS_...].)^
8215 ** ^The current value of the parameter is returned into *pCurrent.
8216 ** ^The highest recorded value is returned in *pHighwater.  ^If the
8217 ** resetFlag is true, then the highest record value is reset after
8218 ** *pHighwater is written.  ^(Some parameters do not record the highest
8219 ** value.  For those parameters
8220 ** nothing is written into *pHighwater and the resetFlag is ignored.)^
8221 ** ^(Other parameters record only the highwater mark and not the current
8222 ** value.  For these latter parameters nothing is written into *pCurrent.)^
8223 **
8224 ** ^The sqlite3_status() and sqlite3_status64() routines return
8225 ** SQLITE_OK on success and a non-zero [error code] on failure.
8226 **
8227 ** If either the current value or the highwater mark is too large to
8228 ** be represented by a 32-bit integer, then the values returned by
8229 ** sqlite3_status() are undefined.
8230 **
8231 ** See also: [sqlite3_db_status()]
8232 */
8233 SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
8234 SQLITE_API int sqlite3_status64(
8235   int op,
8236   sqlite3_int64 *pCurrent,
8237   sqlite3_int64 *pHighwater,
8238   int resetFlag
8239 );
8240 
8241 
8242 /*
8243 ** CAPI3REF: Status Parameters
8244 ** KEYWORDS: {status parameters}
8245 **
8246 ** These integer constants designate various run-time status parameters
8247 ** that can be returned by [sqlite3_status()].
8248 **
8249 ** <dl>
8250 ** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
8251 ** <dd>This parameter is the current amount of memory checked out
8252 ** using [sqlite3_malloc()], either directly or indirectly.  The
8253 ** figure includes calls made to [sqlite3_malloc()] by the application
8254 ** and internal memory usage by the SQLite library.  Auxiliary page-cache
8255 ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
8256 ** this parameter.  The amount returned is the sum of the allocation
8257 ** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
8258 **
8259 ** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
8260 ** <dd>This parameter records the largest memory allocation request
8261 ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
8262 ** internal equivalents).  Only the value returned in the
8263 ** *pHighwater parameter to [sqlite3_status()] is of interest.
8264 ** The value written into the *pCurrent parameter is undefined.</dd>)^
8265 **
8266 ** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
8267 ** <dd>This parameter records the number of separate memory allocations
8268 ** currently checked out.</dd>)^
8269 **
8270 ** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
8271 ** <dd>This parameter returns the number of pages used out of the
8272 ** [pagecache memory allocator] that was configured using
8273 ** [SQLITE_CONFIG_PAGECACHE].  The
8274 ** value returned is in pages, not in bytes.</dd>)^
8275 **
8276 ** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]]
8277 ** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
8278 ** <dd>This parameter returns the number of bytes of page cache
8279 ** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
8280 ** buffer and where forced to overflow to [sqlite3_malloc()].  The
8281 ** returned value includes allocations that overflowed because they
8282 ** where too large (they were larger than the "sz" parameter to
8283 ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
8284 ** no space was left in the page cache.</dd>)^
8285 **
8286 ** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
8287 ** <dd>This parameter records the largest memory allocation request
8288 ** handed to the [pagecache memory allocator].  Only the value returned in the
8289 ** *pHighwater parameter to [sqlite3_status()] is of interest.
8290 ** The value written into the *pCurrent parameter is undefined.</dd>)^
8291 **
8292 ** [[SQLITE_STATUS_SCRATCH_USED]] <dt>SQLITE_STATUS_SCRATCH_USED</dt>
8293 ** <dd>No longer used.</dd>
8294 **
8295 ** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
8296 ** <dd>No longer used.</dd>
8297 **
8298 ** [[SQLITE_STATUS_SCRATCH_SIZE]] <dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
8299 ** <dd>No longer used.</dd>
8300 **
8301 ** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
8302 ** <dd>The *pHighwater parameter records the deepest parser stack.
8303 ** The *pCurrent value is undefined.  The *pHighwater value is only
8304 ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
8305 ** </dl>
8306 **
8307 ** New status parameters may be added from time to time.
8308 */
8309 #define SQLITE_STATUS_MEMORY_USED          0
8310 #define SQLITE_STATUS_PAGECACHE_USED       1
8311 #define SQLITE_STATUS_PAGECACHE_OVERFLOW   2
8312 #define SQLITE_STATUS_SCRATCH_USED         3  /* NOT USED */
8313 #define SQLITE_STATUS_SCRATCH_OVERFLOW     4  /* NOT USED */
8314 #define SQLITE_STATUS_MALLOC_SIZE          5
8315 #define SQLITE_STATUS_PARSER_STACK         6
8316 #define SQLITE_STATUS_PAGECACHE_SIZE       7
8317 #define SQLITE_STATUS_SCRATCH_SIZE         8  /* NOT USED */
8318 #define SQLITE_STATUS_MALLOC_COUNT         9
8319 
8320 /*
8321 ** CAPI3REF: Database Connection Status
8322 ** METHOD: sqlite3
8323 **
8324 ** ^This interface is used to retrieve runtime status information
8325 ** about a single [database connection].  ^The first argument is the
8326 ** database connection object to be interrogated.  ^The second argument
8327 ** is an integer constant, taken from the set of
8328 ** [SQLITE_DBSTATUS options], that
8329 ** determines the parameter to interrogate.  The set of
8330 ** [SQLITE_DBSTATUS options] is likely
8331 ** to grow in future releases of SQLite.
8332 **
8333 ** ^The current value of the requested parameter is written into *pCur
8334 ** and the highest instantaneous value is written into *pHiwtr.  ^If
8335 ** the resetFlg is true, then the highest instantaneous value is
8336 ** reset back down to the current value.
8337 **
8338 ** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
8339 ** non-zero [error code] on failure.
8340 **
8341 ** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
8342 */
8343 SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
8344 
8345 /*
8346 ** CAPI3REF: Status Parameters for database connections
8347 ** KEYWORDS: {SQLITE_DBSTATUS options}
8348 **
8349 ** These constants are the available integer "verbs" that can be passed as
8350 ** the second argument to the [sqlite3_db_status()] interface.
8351 **
8352 ** New verbs may be added in future releases of SQLite. Existing verbs
8353 ** might be discontinued. Applications should check the return code from
8354 ** [sqlite3_db_status()] to make sure that the call worked.
8355 ** The [sqlite3_db_status()] interface will return a non-zero error code
8356 ** if a discontinued or unsupported verb is invoked.
8357 **
8358 ** <dl>
8359 ** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
8360 ** <dd>This parameter returns the number of lookaside memory slots currently
8361 ** checked out.</dd>)^
8362 **
8363 ** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
8364 ** <dd>This parameter returns the number of malloc attempts that were
8365 ** satisfied using lookaside memory. Only the high-water value is meaningful;
8366 ** the current value is always zero.)^
8367 **
8368 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]]
8369 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
8370 ** <dd>This parameter returns the number malloc attempts that might have
8371 ** been satisfied using lookaside memory but failed due to the amount of
8372 ** memory requested being larger than the lookaside slot size.
8373 ** Only the high-water value is meaningful;
8374 ** the current value is always zero.)^
8375 **
8376 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]]
8377 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
8378 ** <dd>This parameter returns the number malloc attempts that might have
8379 ** been satisfied using lookaside memory but failed due to all lookaside
8380 ** memory already being in use.
8381 ** Only the high-water value is meaningful;
8382 ** the current value is always zero.)^
8383 **
8384 ** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
8385 ** <dd>This parameter returns the approximate number of bytes of heap
8386 ** memory used by all pager caches associated with the database connection.)^
8387 ** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
8388 **
8389 ** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]]
8390 ** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt>
8391 ** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a
8392 ** pager cache is shared between two or more connections the bytes of heap
8393 ** memory used by that pager cache is divided evenly between the attached
8394 ** connections.)^  In other words, if none of the pager caches associated
8395 ** with the database connection are shared, this request returns the same
8396 ** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are
8397 ** shared, the value returned by this call will be smaller than that returned
8398 ** by DBSTATUS_CACHE_USED. ^The highwater mark associated with
8399 ** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0.
8400 **
8401 ** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
8402 ** <dd>This parameter returns the approximate number of bytes of heap
8403 ** memory used to store the schema for all databases associated
8404 ** with the connection - main, temp, and any [ATTACH]-ed databases.)^
8405 ** ^The full amount of memory used by the schemas is reported, even if the
8406 ** schema memory is shared with other database connections due to
8407 ** [shared cache mode] being enabled.
8408 ** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
8409 **
8410 ** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
8411 ** <dd>This parameter returns the approximate number of bytes of heap
8412 ** and lookaside memory used by all prepared statements associated with
8413 ** the database connection.)^
8414 ** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
8415 ** </dd>
8416 **
8417 ** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt>
8418 ** <dd>This parameter returns the number of pager cache hits that have
8419 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT
8420 ** is always 0.
8421 ** </dd>
8422 **
8423 ** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt>
8424 ** <dd>This parameter returns the number of pager cache misses that have
8425 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS
8426 ** is always 0.
8427 ** </dd>
8428 **
8429 ** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt>
8430 ** <dd>This parameter returns the number of dirty cache entries that have
8431 ** been written to disk. Specifically, the number of pages written to the
8432 ** wal file in wal mode databases, or the number of pages written to the
8433 ** database file in rollback mode databases. Any pages written as part of
8434 ** transaction rollback or database recovery operations are not included.
8435 ** If an IO or other error occurs while writing a page to disk, the effect
8436 ** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The
8437 ** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0.
8438 ** </dd>
8439 **
8440 ** [[SQLITE_DBSTATUS_CACHE_SPILL]] ^(<dt>SQLITE_DBSTATUS_CACHE_SPILL</dt>
8441 ** <dd>This parameter returns the number of dirty cache entries that have
8442 ** been written to disk in the middle of a transaction due to the page
8443 ** cache overflowing. Transactions are more efficient if they are written
8444 ** to disk all at once. When pages spill mid-transaction, that introduces
8445 ** additional overhead. This parameter can be used help identify
8446 ** inefficiencies that can be resolved by increasing the cache size.
8447 ** </dd>
8448 **
8449 ** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt>
8450 ** <dd>This parameter returns zero for the current value if and only if
8451 ** all foreign key constraints (deferred or immediate) have been
8452 ** resolved.)^  ^The highwater mark is always 0.
8453 ** </dd>
8454 ** </dl>
8455 */
8456 #define SQLITE_DBSTATUS_LOOKASIDE_USED       0
8457 #define SQLITE_DBSTATUS_CACHE_USED           1
8458 #define SQLITE_DBSTATUS_SCHEMA_USED          2
8459 #define SQLITE_DBSTATUS_STMT_USED            3
8460 #define SQLITE_DBSTATUS_LOOKASIDE_HIT        4
8461 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE  5
8462 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL  6
8463 #define SQLITE_DBSTATUS_CACHE_HIT            7
8464 #define SQLITE_DBSTATUS_CACHE_MISS           8
8465 #define SQLITE_DBSTATUS_CACHE_WRITE          9
8466 #define SQLITE_DBSTATUS_DEFERRED_FKS        10
8467 #define SQLITE_DBSTATUS_CACHE_USED_SHARED   11
8468 #define SQLITE_DBSTATUS_CACHE_SPILL         12
8469 #define SQLITE_DBSTATUS_MAX                 12   /* Largest defined DBSTATUS */
8470 
8471 
8472 /*
8473 ** CAPI3REF: Prepared Statement Status
8474 ** METHOD: sqlite3_stmt
8475 **
8476 ** ^(Each prepared statement maintains various
8477 ** [SQLITE_STMTSTATUS counters] that measure the number
8478 ** of times it has performed specific operations.)^  These counters can
8479 ** be used to monitor the performance characteristics of the prepared
8480 ** statements.  For example, if the number of table steps greatly exceeds
8481 ** the number of table searches or result rows, that would tend to indicate
8482 ** that the prepared statement is using a full table scan rather than
8483 ** an index.
8484 **
8485 ** ^(This interface is used to retrieve and reset counter values from
8486 ** a [prepared statement].  The first argument is the prepared statement
8487 ** object to be interrogated.  The second argument
8488 ** is an integer code for a specific [SQLITE_STMTSTATUS counter]
8489 ** to be interrogated.)^
8490 ** ^The current value of the requested counter is returned.
8491 ** ^If the resetFlg is true, then the counter is reset to zero after this
8492 ** interface call returns.
8493 **
8494 ** See also: [sqlite3_status()] and [sqlite3_db_status()].
8495 */
8496 SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
8497 
8498 /*
8499 ** CAPI3REF: Status Parameters for prepared statements
8500 ** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters}
8501 **
8502 ** These preprocessor macros define integer codes that name counter
8503 ** values associated with the [sqlite3_stmt_status()] interface.
8504 ** The meanings of the various counters are as follows:
8505 **
8506 ** <dl>
8507 ** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
8508 ** <dd>^This is the number of times that SQLite has stepped forward in
8509 ** a table as part of a full table scan.  Large numbers for this counter
8510 ** may indicate opportunities for performance improvement through
8511 ** careful use of indices.</dd>
8512 **
8513 ** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt>
8514 ** <dd>^This is the number of sort operations that have occurred.
8515 ** A non-zero value in this counter may indicate an opportunity to
8516 ** improvement performance through careful use of indices.</dd>
8517 **
8518 ** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
8519 ** <dd>^This is the number of rows inserted into transient indices that
8520 ** were created automatically in order to help joins run faster.
8521 ** A non-zero value in this counter may indicate an opportunity to
8522 ** improvement performance by adding permanent indices that do not
8523 ** need to be reinitialized each time the statement is run.</dd>
8524 **
8525 ** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt>
8526 ** <dd>^This is the number of virtual machine operations executed
8527 ** by the prepared statement if that number is less than or equal
8528 ** to 2147483647.  The number of virtual machine operations can be
8529 ** used as a proxy for the total work done by the prepared statement.
8530 ** If the number of virtual machine operations exceeds 2147483647
8531 ** then the value returned by this statement status code is undefined.
8532 **
8533 ** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt>
8534 ** <dd>^This is the number of times that the prepare statement has been
8535 ** automatically regenerated due to schema changes or changes to
8536 ** [bound parameters] that might affect the query plan.
8537 **
8538 ** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt>
8539 ** <dd>^This is the number of times that the prepared statement has
8540 ** been run.  A single "run" for the purposes of this counter is one
8541 ** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()].
8542 ** The counter is incremented on the first [sqlite3_step()] call of each
8543 ** cycle.
8544 **
8545 ** [[SQLITE_STMTSTATUS_FILTER_MISS]]
8546 ** [[SQLITE_STMTSTATUS_FILTER HIT]]
8547 ** <dt>SQLITE_STMTSTATUS_FILTER_HIT<br>
8548 ** SQLITE_STMTSTATUS_FILTER_MISS</dt>
8549 ** <dd>^SQLITE_STMTSTATUS_FILTER_HIT is the number of times that a join
8550 ** step was bypassed because a Bloom filter returned not-found.  The
8551 ** corresponding SQLITE_STMTSTATUS_FILTER_MISS value is the number of
8552 ** times that the Bloom filter returned a find, and thus the join step
8553 ** had to be processed as normal.
8554 **
8555 ** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt>
8556 ** <dd>^This is the approximate number of bytes of heap memory
8557 ** used to store the prepared statement.  ^This value is not actually
8558 ** a counter, and so the resetFlg parameter to sqlite3_stmt_status()
8559 ** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED.
8560 ** </dd>
8561 ** </dl>
8562 */
8563 #define SQLITE_STMTSTATUS_FULLSCAN_STEP     1
8564 #define SQLITE_STMTSTATUS_SORT              2
8565 #define SQLITE_STMTSTATUS_AUTOINDEX         3
8566 #define SQLITE_STMTSTATUS_VM_STEP           4
8567 #define SQLITE_STMTSTATUS_REPREPARE         5
8568 #define SQLITE_STMTSTATUS_RUN               6
8569 #define SQLITE_STMTSTATUS_FILTER_MISS       7
8570 #define SQLITE_STMTSTATUS_FILTER_HIT        8
8571 #define SQLITE_STMTSTATUS_MEMUSED           99
8572 
8573 /*
8574 ** CAPI3REF: Custom Page Cache Object
8575 **
8576 ** The sqlite3_pcache type is opaque.  It is implemented by
8577 ** the pluggable module.  The SQLite core has no knowledge of
8578 ** its size or internal structure and never deals with the
8579 ** sqlite3_pcache object except by holding and passing pointers
8580 ** to the object.
8581 **
8582 ** See [sqlite3_pcache_methods2] for additional information.
8583 */
8584 typedef struct sqlite3_pcache sqlite3_pcache;
8585 
8586 /*
8587 ** CAPI3REF: Custom Page Cache Object
8588 **
8589 ** The sqlite3_pcache_page object represents a single page in the
8590 ** page cache.  The page cache will allocate instances of this
8591 ** object.  Various methods of the page cache use pointers to instances
8592 ** of this object as parameters or as their return value.
8593 **
8594 ** See [sqlite3_pcache_methods2] for additional information.
8595 */
8596 typedef struct sqlite3_pcache_page sqlite3_pcache_page;
8597 struct sqlite3_pcache_page {
8598   void *pBuf;        /* The content of the page */
8599   void *pExtra;      /* Extra information associated with the page */
8600 };
8601 
8602 /*
8603 ** CAPI3REF: Application Defined Page Cache.
8604 ** KEYWORDS: {page cache}
8605 **
8606 ** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can
8607 ** register an alternative page cache implementation by passing in an
8608 ** instance of the sqlite3_pcache_methods2 structure.)^
8609 ** In many applications, most of the heap memory allocated by
8610 ** SQLite is used for the page cache.
8611 ** By implementing a
8612 ** custom page cache using this API, an application can better control
8613 ** the amount of memory consumed by SQLite, the way in which
8614 ** that memory is allocated and released, and the policies used to
8615 ** determine exactly which parts of a database file are cached and for
8616 ** how long.
8617 **
8618 ** The alternative page cache mechanism is an
8619 ** extreme measure that is only needed by the most demanding applications.
8620 ** The built-in page cache is recommended for most uses.
8621 **
8622 ** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an
8623 ** internal buffer by SQLite within the call to [sqlite3_config].  Hence
8624 ** the application may discard the parameter after the call to
8625 ** [sqlite3_config()] returns.)^
8626 **
8627 ** [[the xInit() page cache method]]
8628 ** ^(The xInit() method is called once for each effective
8629 ** call to [sqlite3_initialize()])^
8630 ** (usually only once during the lifetime of the process). ^(The xInit()
8631 ** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^
8632 ** The intent of the xInit() method is to set up global data structures
8633 ** required by the custom page cache implementation.
8634 ** ^(If the xInit() method is NULL, then the
8635 ** built-in default page cache is used instead of the application defined
8636 ** page cache.)^
8637 **
8638 ** [[the xShutdown() page cache method]]
8639 ** ^The xShutdown() method is called by [sqlite3_shutdown()].
8640 ** It can be used to clean up
8641 ** any outstanding resources before process shutdown, if required.
8642 ** ^The xShutdown() method may be NULL.
8643 **
8644 ** ^SQLite automatically serializes calls to the xInit method,
8645 ** so the xInit method need not be threadsafe.  ^The
8646 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
8647 ** not need to be threadsafe either.  All other methods must be threadsafe
8648 ** in multithreaded applications.
8649 **
8650 ** ^SQLite will never invoke xInit() more than once without an intervening
8651 ** call to xShutdown().
8652 **
8653 ** [[the xCreate() page cache methods]]
8654 ** ^SQLite invokes the xCreate() method to construct a new cache instance.
8655 ** SQLite will typically create one cache instance for each open database file,
8656 ** though this is not guaranteed. ^The
8657 ** first parameter, szPage, is the size in bytes of the pages that must
8658 ** be allocated by the cache.  ^szPage will always a power of two.  ^The
8659 ** second parameter szExtra is a number of bytes of extra storage
8660 ** associated with each page cache entry.  ^The szExtra parameter will
8661 ** a number less than 250.  SQLite will use the
8662 ** extra szExtra bytes on each page to store metadata about the underlying
8663 ** database page on disk.  The value passed into szExtra depends
8664 ** on the SQLite version, the target platform, and how SQLite was compiled.
8665 ** ^The third argument to xCreate(), bPurgeable, is true if the cache being
8666 ** created will be used to cache database pages of a file stored on disk, or
8667 ** false if it is used for an in-memory database. The cache implementation
8668 ** does not have to do anything special based with the value of bPurgeable;
8669 ** it is purely advisory.  ^On a cache where bPurgeable is false, SQLite will
8670 ** never invoke xUnpin() except to deliberately delete a page.
8671 ** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
8672 ** false will always have the "discard" flag set to true.
8673 ** ^Hence, a cache created with bPurgeable false will
8674 ** never contain any unpinned pages.
8675 **
8676 ** [[the xCachesize() page cache method]]
8677 ** ^(The xCachesize() method may be called at any time by SQLite to set the
8678 ** suggested maximum cache-size (number of pages stored by) the cache
8679 ** instance passed as the first argument. This is the value configured using
8680 ** the SQLite "[PRAGMA cache_size]" command.)^  As with the bPurgeable
8681 ** parameter, the implementation is not required to do anything with this
8682 ** value; it is advisory only.
8683 **
8684 ** [[the xPagecount() page cache methods]]
8685 ** The xPagecount() method must return the number of pages currently
8686 ** stored in the cache, both pinned and unpinned.
8687 **
8688 ** [[the xFetch() page cache methods]]
8689 ** The xFetch() method locates a page in the cache and returns a pointer to
8690 ** an sqlite3_pcache_page object associated with that page, or a NULL pointer.
8691 ** The pBuf element of the returned sqlite3_pcache_page object will be a
8692 ** pointer to a buffer of szPage bytes used to store the content of a
8693 ** single database page.  The pExtra element of sqlite3_pcache_page will be
8694 ** a pointer to the szExtra bytes of extra storage that SQLite has requested
8695 ** for each entry in the page cache.
8696 **
8697 ** The page to be fetched is determined by the key. ^The minimum key value
8698 ** is 1.  After it has been retrieved using xFetch, the page is considered
8699 ** to be "pinned".
8700 **
8701 ** If the requested page is already in the page cache, then the page cache
8702 ** implementation must return a pointer to the page buffer with its content
8703 ** intact.  If the requested page is not already in the cache, then the
8704 ** cache implementation should use the value of the createFlag
8705 ** parameter to help it determined what action to take:
8706 **
8707 ** <table border=1 width=85% align=center>
8708 ** <tr><th> createFlag <th> Behavior when page is not already in cache
8709 ** <tr><td> 0 <td> Do not allocate a new page.  Return NULL.
8710 ** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
8711 **                 Otherwise return NULL.
8712 ** <tr><td> 2 <td> Make every effort to allocate a new page.  Only return
8713 **                 NULL if allocating a new page is effectively impossible.
8714 ** </table>
8715 **
8716 ** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1.  SQLite
8717 ** will only use a createFlag of 2 after a prior call with a createFlag of 1
8718 ** failed.)^  In between the xFetch() calls, SQLite may
8719 ** attempt to unpin one or more cache pages by spilling the content of
8720 ** pinned pages to disk and synching the operating system disk cache.
8721 **
8722 ** [[the xUnpin() page cache method]]
8723 ** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
8724 ** as its second argument.  If the third parameter, discard, is non-zero,
8725 ** then the page must be evicted from the cache.
8726 ** ^If the discard parameter is
8727 ** zero, then the page may be discarded or retained at the discretion of
8728 ** page cache implementation. ^The page cache implementation
8729 ** may choose to evict unpinned pages at any time.
8730 **
8731 ** The cache must not perform any reference counting. A single
8732 ** call to xUnpin() unpins the page regardless of the number of prior calls
8733 ** to xFetch().
8734 **
8735 ** [[the xRekey() page cache methods]]
8736 ** The xRekey() method is used to change the key value associated with the
8737 ** page passed as the second argument. If the cache
8738 ** previously contains an entry associated with newKey, it must be
8739 ** discarded. ^Any prior cache entry associated with newKey is guaranteed not
8740 ** to be pinned.
8741 **
8742 ** When SQLite calls the xTruncate() method, the cache must discard all
8743 ** existing cache entries with page numbers (keys) greater than or equal
8744 ** to the value of the iLimit parameter passed to xTruncate(). If any
8745 ** of these pages are pinned, they are implicitly unpinned, meaning that
8746 ** they can be safely discarded.
8747 **
8748 ** [[the xDestroy() page cache method]]
8749 ** ^The xDestroy() method is used to delete a cache allocated by xCreate().
8750 ** All resources associated with the specified cache should be freed. ^After
8751 ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
8752 ** handle invalid, and will not use it with any other sqlite3_pcache_methods2
8753 ** functions.
8754 **
8755 ** [[the xShrink() page cache method]]
8756 ** ^SQLite invokes the xShrink() method when it wants the page cache to
8757 ** free up as much of heap memory as possible.  The page cache implementation
8758 ** is not obligated to free any memory, but well-behaved implementations should
8759 ** do their best.
8760 */
8761 typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
8762 struct sqlite3_pcache_methods2 {
8763   int iVersion;
8764   void *pArg;
8765   int (*xInit)(void*);
8766   void (*xShutdown)(void*);
8767   sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
8768   void (*xCachesize)(sqlite3_pcache*, int nCachesize);
8769   int (*xPagecount)(sqlite3_pcache*);
8770   sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
8771   void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
8772   void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*,
8773       unsigned oldKey, unsigned newKey);
8774   void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
8775   void (*xDestroy)(sqlite3_pcache*);
8776   void (*xShrink)(sqlite3_pcache*);
8777 };
8778 
8779 /*
8780 ** This is the obsolete pcache_methods object that has now been replaced
8781 ** by sqlite3_pcache_methods2.  This object is not used by SQLite.  It is
8782 ** retained in the header file for backwards compatibility only.
8783 */
8784 typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
8785 struct sqlite3_pcache_methods {
8786   void *pArg;
8787   int (*xInit)(void*);
8788   void (*xShutdown)(void*);
8789   sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
8790   void (*xCachesize)(sqlite3_pcache*, int nCachesize);
8791   int (*xPagecount)(sqlite3_pcache*);
8792   void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
8793   void (*xUnpin)(sqlite3_pcache*, void*, int discard);
8794   void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
8795   void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
8796   void (*xDestroy)(sqlite3_pcache*);
8797 };
8798 
8799 
8800 /*
8801 ** CAPI3REF: Online Backup Object
8802 **
8803 ** The sqlite3_backup object records state information about an ongoing
8804 ** online backup operation.  ^The sqlite3_backup object is created by
8805 ** a call to [sqlite3_backup_init()] and is destroyed by a call to
8806 ** [sqlite3_backup_finish()].
8807 **
8808 ** See Also: [Using the SQLite Online Backup API]
8809 */
8810 typedef struct sqlite3_backup sqlite3_backup;
8811 
8812 /*
8813 ** CAPI3REF: Online Backup API.
8814 **
8815 ** The backup API copies the content of one database into another.
8816 ** It is useful either for creating backups of databases or
8817 ** for copying in-memory databases to or from persistent files.
8818 **
8819 ** See Also: [Using the SQLite Online Backup API]
8820 **
8821 ** ^SQLite holds a write transaction open on the destination database file
8822 ** for the duration of the backup operation.
8823 ** ^The source database is read-locked only while it is being read;
8824 ** it is not locked continuously for the entire backup operation.
8825 ** ^Thus, the backup may be performed on a live source database without
8826 ** preventing other database connections from
8827 ** reading or writing to the source database while the backup is underway.
8828 **
8829 ** ^(To perform a backup operation:
8830 **   <ol>
8831 **     <li><b>sqlite3_backup_init()</b> is called once to initialize the
8832 **         backup,
8833 **     <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
8834 **         the data between the two databases, and finally
8835 **     <li><b>sqlite3_backup_finish()</b> is called to release all resources
8836 **         associated with the backup operation.
8837 **   </ol>)^
8838 ** There should be exactly one call to sqlite3_backup_finish() for each
8839 ** successful call to sqlite3_backup_init().
8840 **
8841 ** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
8842 **
8843 ** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
8844 ** [database connection] associated with the destination database
8845 ** and the database name, respectively.
8846 ** ^The database name is "main" for the main database, "temp" for the
8847 ** temporary database, or the name specified after the AS keyword in
8848 ** an [ATTACH] statement for an attached database.
8849 ** ^The S and M arguments passed to
8850 ** sqlite3_backup_init(D,N,S,M) identify the [database connection]
8851 ** and database name of the source database, respectively.
8852 ** ^The source and destination [database connections] (parameters S and D)
8853 ** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
8854 ** an error.
8855 **
8856 ** ^A call to sqlite3_backup_init() will fail, returning NULL, if
8857 ** there is already a read or read-write transaction open on the
8858 ** destination database.
8859 **
8860 ** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
8861 ** returned and an error code and error message are stored in the
8862 ** destination [database connection] D.
8863 ** ^The error code and message for the failed call to sqlite3_backup_init()
8864 ** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
8865 ** [sqlite3_errmsg16()] functions.
8866 ** ^A successful call to sqlite3_backup_init() returns a pointer to an
8867 ** [sqlite3_backup] object.
8868 ** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
8869 ** sqlite3_backup_finish() functions to perform the specified backup
8870 ** operation.
8871 **
8872 ** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
8873 **
8874 ** ^Function sqlite3_backup_step(B,N) will copy up to N pages between
8875 ** the source and destination databases specified by [sqlite3_backup] object B.
8876 ** ^If N is negative, all remaining source pages are copied.
8877 ** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
8878 ** are still more pages to be copied, then the function returns [SQLITE_OK].
8879 ** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
8880 ** from source to destination, then it returns [SQLITE_DONE].
8881 ** ^If an error occurs while running sqlite3_backup_step(B,N),
8882 ** then an [error code] is returned. ^As well as [SQLITE_OK] and
8883 ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
8884 ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
8885 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
8886 **
8887 ** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
8888 ** <ol>
8889 ** <li> the destination database was opened read-only, or
8890 ** <li> the destination database is using write-ahead-log journaling
8891 ** and the destination and source page sizes differ, or
8892 ** <li> the destination database is an in-memory database and the
8893 ** destination and source page sizes differ.
8894 ** </ol>)^
8895 **
8896 ** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
8897 ** the [sqlite3_busy_handler | busy-handler function]
8898 ** is invoked (if one is specified). ^If the
8899 ** busy-handler returns non-zero before the lock is available, then
8900 ** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
8901 ** sqlite3_backup_step() can be retried later. ^If the source
8902 ** [database connection]
8903 ** is being used to write to the source database when sqlite3_backup_step()
8904 ** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
8905 ** case the call to sqlite3_backup_step() can be retried later on. ^(If
8906 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
8907 ** [SQLITE_READONLY] is returned, then
8908 ** there is no point in retrying the call to sqlite3_backup_step(). These
8909 ** errors are considered fatal.)^  The application must accept
8910 ** that the backup operation has failed and pass the backup operation handle
8911 ** to the sqlite3_backup_finish() to release associated resources.
8912 **
8913 ** ^The first call to sqlite3_backup_step() obtains an exclusive lock
8914 ** on the destination file. ^The exclusive lock is not released until either
8915 ** sqlite3_backup_finish() is called or the backup operation is complete
8916 ** and sqlite3_backup_step() returns [SQLITE_DONE].  ^Every call to
8917 ** sqlite3_backup_step() obtains a [shared lock] on the source database that
8918 ** lasts for the duration of the sqlite3_backup_step() call.
8919 ** ^Because the source database is not locked between calls to
8920 ** sqlite3_backup_step(), the source database may be modified mid-way
8921 ** through the backup process.  ^If the source database is modified by an
8922 ** external process or via a database connection other than the one being
8923 ** used by the backup operation, then the backup will be automatically
8924 ** restarted by the next call to sqlite3_backup_step(). ^If the source
8925 ** database is modified by the using the same database connection as is used
8926 ** by the backup operation, then the backup database is automatically
8927 ** updated at the same time.
8928 **
8929 ** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
8930 **
8931 ** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the
8932 ** application wishes to abandon the backup operation, the application
8933 ** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
8934 ** ^The sqlite3_backup_finish() interfaces releases all
8935 ** resources associated with the [sqlite3_backup] object.
8936 ** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
8937 ** active write-transaction on the destination database is rolled back.
8938 ** The [sqlite3_backup] object is invalid
8939 ** and may not be used following a call to sqlite3_backup_finish().
8940 **
8941 ** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
8942 ** sqlite3_backup_step() errors occurred, regardless or whether or not
8943 ** sqlite3_backup_step() completed.
8944 ** ^If an out-of-memory condition or IO error occurred during any prior
8945 ** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
8946 ** sqlite3_backup_finish() returns the corresponding [error code].
8947 **
8948 ** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
8949 ** is not a permanent error and does not affect the return value of
8950 ** sqlite3_backup_finish().
8951 **
8952 ** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]]
8953 ** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
8954 **
8955 ** ^The sqlite3_backup_remaining() routine returns the number of pages still
8956 ** to be backed up at the conclusion of the most recent sqlite3_backup_step().
8957 ** ^The sqlite3_backup_pagecount() routine returns the total number of pages
8958 ** in the source database at the conclusion of the most recent
8959 ** sqlite3_backup_step().
8960 ** ^(The values returned by these functions are only updated by
8961 ** sqlite3_backup_step(). If the source database is modified in a way that
8962 ** changes the size of the source database or the number of pages remaining,
8963 ** those changes are not reflected in the output of sqlite3_backup_pagecount()
8964 ** and sqlite3_backup_remaining() until after the next
8965 ** sqlite3_backup_step().)^
8966 **
8967 ** <b>Concurrent Usage of Database Handles</b>
8968 **
8969 ** ^The source [database connection] may be used by the application for other
8970 ** purposes while a backup operation is underway or being initialized.
8971 ** ^If SQLite is compiled and configured to support threadsafe database
8972 ** connections, then the source database connection may be used concurrently
8973 ** from within other threads.
8974 **
8975 ** However, the application must guarantee that the destination
8976 ** [database connection] is not passed to any other API (by any thread) after
8977 ** sqlite3_backup_init() is called and before the corresponding call to
8978 ** sqlite3_backup_finish().  SQLite does not currently check to see
8979 ** if the application incorrectly accesses the destination [database connection]
8980 ** and so no error code is reported, but the operations may malfunction
8981 ** nevertheless.  Use of the destination database connection while a
8982 ** backup is in progress might also also cause a mutex deadlock.
8983 **
8984 ** If running in [shared cache mode], the application must
8985 ** guarantee that the shared cache used by the destination database
8986 ** is not accessed while the backup is running. In practice this means
8987 ** that the application must guarantee that the disk file being
8988 ** backed up to is not accessed by any connection within the process,
8989 ** not just the specific connection that was passed to sqlite3_backup_init().
8990 **
8991 ** The [sqlite3_backup] object itself is partially threadsafe. Multiple
8992 ** threads may safely make multiple concurrent calls to sqlite3_backup_step().
8993 ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
8994 ** APIs are not strictly speaking threadsafe. If they are invoked at the
8995 ** same time as another thread is invoking sqlite3_backup_step() it is
8996 ** possible that they return invalid values.
8997 */
8998 SQLITE_API sqlite3_backup *sqlite3_backup_init(
8999   sqlite3 *pDest,                        /* Destination database handle */
9000   const char *zDestName,                 /* Destination database name */
9001   sqlite3 *pSource,                      /* Source database handle */
9002   const char *zSourceName                /* Source database name */
9003 );
9004 SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage);
9005 SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p);
9006 SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p);
9007 SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p);
9008 
9009 /*
9010 ** CAPI3REF: Unlock Notification
9011 ** METHOD: sqlite3
9012 **
9013 ** ^When running in shared-cache mode, a database operation may fail with
9014 ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
9015 ** individual tables within the shared-cache cannot be obtained. See
9016 ** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
9017 ** ^This API may be used to register a callback that SQLite will invoke
9018 ** when the connection currently holding the required lock relinquishes it.
9019 ** ^This API is only available if the library was compiled with the
9020 ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
9021 **
9022 ** See Also: [Using the SQLite Unlock Notification Feature].
9023 **
9024 ** ^Shared-cache locks are released when a database connection concludes
9025 ** its current transaction, either by committing it or rolling it back.
9026 **
9027 ** ^When a connection (known as the blocked connection) fails to obtain a
9028 ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
9029 ** identity of the database connection (the blocking connection) that
9030 ** has locked the required resource is stored internally. ^After an
9031 ** application receives an SQLITE_LOCKED error, it may call the
9032 ** sqlite3_unlock_notify() method with the blocked connection handle as
9033 ** the first argument to register for a callback that will be invoked
9034 ** when the blocking connections current transaction is concluded. ^The
9035 ** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
9036 ** call that concludes the blocking connection's transaction.
9037 **
9038 ** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
9039 ** there is a chance that the blocking connection will have already
9040 ** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
9041 ** If this happens, then the specified callback is invoked immediately,
9042 ** from within the call to sqlite3_unlock_notify().)^
9043 **
9044 ** ^If the blocked connection is attempting to obtain a write-lock on a
9045 ** shared-cache table, and more than one other connection currently holds
9046 ** a read-lock on the same table, then SQLite arbitrarily selects one of
9047 ** the other connections to use as the blocking connection.
9048 **
9049 ** ^(There may be at most one unlock-notify callback registered by a
9050 ** blocked connection. If sqlite3_unlock_notify() is called when the
9051 ** blocked connection already has a registered unlock-notify callback,
9052 ** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
9053 ** called with a NULL pointer as its second argument, then any existing
9054 ** unlock-notify callback is canceled. ^The blocked connections
9055 ** unlock-notify callback may also be canceled by closing the blocked
9056 ** connection using [sqlite3_close()].
9057 **
9058 ** The unlock-notify callback is not reentrant. If an application invokes
9059 ** any sqlite3_xxx API functions from within an unlock-notify callback, a
9060 ** crash or deadlock may be the result.
9061 **
9062 ** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
9063 ** returns SQLITE_OK.
9064 **
9065 ** <b>Callback Invocation Details</b>
9066 **
9067 ** When an unlock-notify callback is registered, the application provides a
9068 ** single void* pointer that is passed to the callback when it is invoked.
9069 ** However, the signature of the callback function allows SQLite to pass
9070 ** it an array of void* context pointers. The first argument passed to
9071 ** an unlock-notify callback is a pointer to an array of void* pointers,
9072 ** and the second is the number of entries in the array.
9073 **
9074 ** When a blocking connection's transaction is concluded, there may be
9075 ** more than one blocked connection that has registered for an unlock-notify
9076 ** callback. ^If two or more such blocked connections have specified the
9077 ** same callback function, then instead of invoking the callback function
9078 ** multiple times, it is invoked once with the set of void* context pointers
9079 ** specified by the blocked connections bundled together into an array.
9080 ** This gives the application an opportunity to prioritize any actions
9081 ** related to the set of unblocked database connections.
9082 **
9083 ** <b>Deadlock Detection</b>
9084 **
9085 ** Assuming that after registering for an unlock-notify callback a
9086 ** database waits for the callback to be issued before taking any further
9087 ** action (a reasonable assumption), then using this API may cause the
9088 ** application to deadlock. For example, if connection X is waiting for
9089 ** connection Y's transaction to be concluded, and similarly connection
9090 ** Y is waiting on connection X's transaction, then neither connection
9091 ** will proceed and the system may remain deadlocked indefinitely.
9092 **
9093 ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
9094 ** detection. ^If a given call to sqlite3_unlock_notify() would put the
9095 ** system in a deadlocked state, then SQLITE_LOCKED is returned and no
9096 ** unlock-notify callback is registered. The system is said to be in
9097 ** a deadlocked state if connection A has registered for an unlock-notify
9098 ** callback on the conclusion of connection B's transaction, and connection
9099 ** B has itself registered for an unlock-notify callback when connection
9100 ** A's transaction is concluded. ^Indirect deadlock is also detected, so
9101 ** the system is also considered to be deadlocked if connection B has
9102 ** registered for an unlock-notify callback on the conclusion of connection
9103 ** C's transaction, where connection C is waiting on connection A. ^Any
9104 ** number of levels of indirection are allowed.
9105 **
9106 ** <b>The "DROP TABLE" Exception</b>
9107 **
9108 ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost
9109 ** always appropriate to call sqlite3_unlock_notify(). There is however,
9110 ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
9111 ** SQLite checks if there are any currently executing SELECT statements
9112 ** that belong to the same connection. If there are, SQLITE_LOCKED is
9113 ** returned. In this case there is no "blocking connection", so invoking
9114 ** sqlite3_unlock_notify() results in the unlock-notify callback being
9115 ** invoked immediately. If the application then re-attempts the "DROP TABLE"
9116 ** or "DROP INDEX" query, an infinite loop might be the result.
9117 **
9118 ** One way around this problem is to check the extended error code returned
9119 ** by an sqlite3_step() call. ^(If there is a blocking connection, then the
9120 ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
9121 ** the special "DROP TABLE/INDEX" case, the extended error code is just
9122 ** SQLITE_LOCKED.)^
9123 */
9124 SQLITE_API int sqlite3_unlock_notify(
9125   sqlite3 *pBlocked,                          /* Waiting connection */
9126   void (*xNotify)(void **apArg, int nArg),    /* Callback function to invoke */
9127   void *pNotifyArg                            /* Argument to pass to xNotify */
9128 );
9129 
9130 
9131 /*
9132 ** CAPI3REF: String Comparison
9133 **
9134 ** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications
9135 ** and extensions to compare the contents of two buffers containing UTF-8
9136 ** strings in a case-independent fashion, using the same definition of "case
9137 ** independence" that SQLite uses internally when comparing identifiers.
9138 */
9139 SQLITE_API int sqlite3_stricmp(const char *, const char *);
9140 SQLITE_API int sqlite3_strnicmp(const char *, const char *, int);
9141 
9142 /*
9143 ** CAPI3REF: String Globbing
9144 *
9145 ** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if
9146 ** string X matches the [GLOB] pattern P.
9147 ** ^The definition of [GLOB] pattern matching used in
9148 ** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the
9149 ** SQL dialect understood by SQLite.  ^The [sqlite3_strglob(P,X)] function
9150 ** is case sensitive.
9151 **
9152 ** Note that this routine returns zero on a match and non-zero if the strings
9153 ** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
9154 **
9155 ** See also: [sqlite3_strlike()].
9156 */
9157 SQLITE_API int sqlite3_strglob(const char *zGlob, const char *zStr);
9158 
9159 /*
9160 ** CAPI3REF: String LIKE Matching
9161 *
9162 ** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if
9163 ** string X matches the [LIKE] pattern P with escape character E.
9164 ** ^The definition of [LIKE] pattern matching used in
9165 ** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E"
9166 ** operator in the SQL dialect understood by SQLite.  ^For "X LIKE P" without
9167 ** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0.
9168 ** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case
9169 ** insensitive - equivalent upper and lower case ASCII characters match
9170 ** one another.
9171 **
9172 ** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though
9173 ** only ASCII characters are case folded.
9174 **
9175 ** Note that this routine returns zero on a match and non-zero if the strings
9176 ** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
9177 **
9178 ** See also: [sqlite3_strglob()].
9179 */
9180 SQLITE_API int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc);
9181 
9182 /*
9183 ** CAPI3REF: Error Logging Interface
9184 **
9185 ** ^The [sqlite3_log()] interface writes a message into the [error log]
9186 ** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
9187 ** ^If logging is enabled, the zFormat string and subsequent arguments are
9188 ** used with [sqlite3_snprintf()] to generate the final output string.
9189 **
9190 ** The sqlite3_log() interface is intended for use by extensions such as
9191 ** virtual tables, collating functions, and SQL functions.  While there is
9192 ** nothing to prevent an application from calling sqlite3_log(), doing so
9193 ** is considered bad form.
9194 **
9195 ** The zFormat string must not be NULL.
9196 **
9197 ** To avoid deadlocks and other threading problems, the sqlite3_log() routine
9198 ** will not use dynamically allocated memory.  The log message is stored in
9199 ** a fixed-length buffer on the stack.  If the log message is longer than
9200 ** a few hundred characters, it will be truncated to the length of the
9201 ** buffer.
9202 */
9203 SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...);
9204 
9205 /*
9206 ** CAPI3REF: Write-Ahead Log Commit Hook
9207 ** METHOD: sqlite3
9208 **
9209 ** ^The [sqlite3_wal_hook()] function is used to register a callback that
9210 ** is invoked each time data is committed to a database in wal mode.
9211 **
9212 ** ^(The callback is invoked by SQLite after the commit has taken place and
9213 ** the associated write-lock on the database released)^, so the implementation
9214 ** may read, write or [checkpoint] the database as required.
9215 **
9216 ** ^The first parameter passed to the callback function when it is invoked
9217 ** is a copy of the third parameter passed to sqlite3_wal_hook() when
9218 ** registering the callback. ^The second is a copy of the database handle.
9219 ** ^The third parameter is the name of the database that was written to -
9220 ** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
9221 ** is the number of pages currently in the write-ahead log file,
9222 ** including those that were just committed.
9223 **
9224 ** The callback function should normally return [SQLITE_OK].  ^If an error
9225 ** code is returned, that error will propagate back up through the
9226 ** SQLite code base to cause the statement that provoked the callback
9227 ** to report an error, though the commit will have still occurred. If the
9228 ** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
9229 ** that does not correspond to any valid SQLite error code, the results
9230 ** are undefined.
9231 **
9232 ** A single database handle may have at most a single write-ahead log callback
9233 ** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
9234 ** previously registered write-ahead log callback. ^The return value is
9235 ** a copy of the third parameter from the previous call, if any, or 0.
9236 ** ^Note that the [sqlite3_wal_autocheckpoint()] interface and the
9237 ** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
9238 ** overwrite any prior [sqlite3_wal_hook()] settings.
9239 */
9240 SQLITE_API void *sqlite3_wal_hook(
9241   sqlite3*,
9242   int(*)(void *,sqlite3*,const char*,int),
9243   void*
9244 );
9245 
9246 /*
9247 ** CAPI3REF: Configure an auto-checkpoint
9248 ** METHOD: sqlite3
9249 **
9250 ** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
9251 ** [sqlite3_wal_hook()] that causes any database on [database connection] D
9252 ** to automatically [checkpoint]
9253 ** after committing a transaction if there are N or
9254 ** more frames in the [write-ahead log] file.  ^Passing zero or
9255 ** a negative value as the nFrame parameter disables automatic
9256 ** checkpoints entirely.
9257 **
9258 ** ^The callback registered by this function replaces any existing callback
9259 ** registered using [sqlite3_wal_hook()].  ^Likewise, registering a callback
9260 ** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
9261 ** configured by this function.
9262 **
9263 ** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
9264 ** from SQL.
9265 **
9266 ** ^Checkpoints initiated by this mechanism are
9267 ** [sqlite3_wal_checkpoint_v2|PASSIVE].
9268 **
9269 ** ^Every new [database connection] defaults to having the auto-checkpoint
9270 ** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
9271 ** pages.  The use of this interface
9272 ** is only necessary if the default setting is found to be suboptimal
9273 ** for a particular application.
9274 */
9275 SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
9276 
9277 /*
9278 ** CAPI3REF: Checkpoint a database
9279 ** METHOD: sqlite3
9280 **
9281 ** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to
9282 ** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^
9283 **
9284 ** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the
9285 ** [write-ahead log] for database X on [database connection] D to be
9286 ** transferred into the database file and for the write-ahead log to
9287 ** be reset.  See the [checkpointing] documentation for addition
9288 ** information.
9289 **
9290 ** This interface used to be the only way to cause a checkpoint to
9291 ** occur.  But then the newer and more powerful [sqlite3_wal_checkpoint_v2()]
9292 ** interface was added.  This interface is retained for backwards
9293 ** compatibility and as a convenience for applications that need to manually
9294 ** start a callback but which do not need the full power (and corresponding
9295 ** complication) of [sqlite3_wal_checkpoint_v2()].
9296 */
9297 SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
9298 
9299 /*
9300 ** CAPI3REF: Checkpoint a database
9301 ** METHOD: sqlite3
9302 **
9303 ** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint
9304 ** operation on database X of [database connection] D in mode M.  Status
9305 ** information is written back into integers pointed to by L and C.)^
9306 ** ^(The M parameter must be a valid [checkpoint mode]:)^
9307 **
9308 ** <dl>
9309 ** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
9310 **   ^Checkpoint as many frames as possible without waiting for any database
9311 **   readers or writers to finish, then sync the database file if all frames
9312 **   in the log were checkpointed. ^The [busy-handler callback]
9313 **   is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode.
9314 **   ^On the other hand, passive mode might leave the checkpoint unfinished
9315 **   if there are concurrent readers or writers.
9316 **
9317 ** <dt>SQLITE_CHECKPOINT_FULL<dd>
9318 **   ^This mode blocks (it invokes the
9319 **   [sqlite3_busy_handler|busy-handler callback]) until there is no
9320 **   database writer and all readers are reading from the most recent database
9321 **   snapshot. ^It then checkpoints all frames in the log file and syncs the
9322 **   database file. ^This mode blocks new database writers while it is pending,
9323 **   but new database readers are allowed to continue unimpeded.
9324 **
9325 ** <dt>SQLITE_CHECKPOINT_RESTART<dd>
9326 **   ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition
9327 **   that after checkpointing the log file it blocks (calls the
9328 **   [busy-handler callback])
9329 **   until all readers are reading from the database file only. ^This ensures
9330 **   that the next writer will restart the log file from the beginning.
9331 **   ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new
9332 **   database writer attempts while it is pending, but does not impede readers.
9333 **
9334 ** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd>
9335 **   ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the
9336 **   addition that it also truncates the log file to zero bytes just prior
9337 **   to a successful return.
9338 ** </dl>
9339 **
9340 ** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in
9341 ** the log file or to -1 if the checkpoint could not run because
9342 ** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not
9343 ** NULL,then *pnCkpt is set to the total number of checkpointed frames in the
9344 ** log file (including any that were already checkpointed before the function
9345 ** was called) or to -1 if the checkpoint could not run due to an error or
9346 ** because the database is not in WAL mode. ^Note that upon successful
9347 ** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been
9348 ** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero.
9349 **
9350 ** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If
9351 ** any other process is running a checkpoint operation at the same time, the
9352 ** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a
9353 ** busy-handler configured, it will not be invoked in this case.
9354 **
9355 ** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the
9356 ** exclusive "writer" lock on the database file. ^If the writer lock cannot be
9357 ** obtained immediately, and a busy-handler is configured, it is invoked and
9358 ** the writer lock retried until either the busy-handler returns 0 or the lock
9359 ** is successfully obtained. ^The busy-handler is also invoked while waiting for
9360 ** database readers as described above. ^If the busy-handler returns 0 before
9361 ** the writer lock is obtained or while waiting for database readers, the
9362 ** checkpoint operation proceeds from that point in the same way as
9363 ** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible
9364 ** without blocking any further. ^SQLITE_BUSY is returned in this case.
9365 **
9366 ** ^If parameter zDb is NULL or points to a zero length string, then the
9367 ** specified operation is attempted on all WAL databases [attached] to
9368 ** [database connection] db.  In this case the
9369 ** values written to output parameters *pnLog and *pnCkpt are undefined. ^If
9370 ** an SQLITE_BUSY error is encountered when processing one or more of the
9371 ** attached WAL databases, the operation is still attempted on any remaining
9372 ** attached databases and SQLITE_BUSY is returned at the end. ^If any other
9373 ** error occurs while processing an attached database, processing is abandoned
9374 ** and the error code is returned to the caller immediately. ^If no error
9375 ** (SQLITE_BUSY or otherwise) is encountered while processing the attached
9376 ** databases, SQLITE_OK is returned.
9377 **
9378 ** ^If database zDb is the name of an attached database that is not in WAL
9379 ** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If
9380 ** zDb is not NULL (or a zero length string) and is not the name of any
9381 ** attached database, SQLITE_ERROR is returned to the caller.
9382 **
9383 ** ^Unless it returns SQLITE_MISUSE,
9384 ** the sqlite3_wal_checkpoint_v2() interface
9385 ** sets the error information that is queried by
9386 ** [sqlite3_errcode()] and [sqlite3_errmsg()].
9387 **
9388 ** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface
9389 ** from SQL.
9390 */
9391 SQLITE_API int sqlite3_wal_checkpoint_v2(
9392   sqlite3 *db,                    /* Database handle */
9393   const char *zDb,                /* Name of attached database (or NULL) */
9394   int eMode,                      /* SQLITE_CHECKPOINT_* value */
9395   int *pnLog,                     /* OUT: Size of WAL log in frames */
9396   int *pnCkpt                     /* OUT: Total number of frames checkpointed */
9397 );
9398 
9399 /*
9400 ** CAPI3REF: Checkpoint Mode Values
9401 ** KEYWORDS: {checkpoint mode}
9402 **
9403 ** These constants define all valid values for the "checkpoint mode" passed
9404 ** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface.
9405 ** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the
9406 ** meaning of each of these checkpoint modes.
9407 */
9408 #define SQLITE_CHECKPOINT_PASSIVE  0  /* Do as much as possible w/o blocking */
9409 #define SQLITE_CHECKPOINT_FULL     1  /* Wait for writers, then checkpoint */
9410 #define SQLITE_CHECKPOINT_RESTART  2  /* Like FULL but wait for for readers */
9411 #define SQLITE_CHECKPOINT_TRUNCATE 3  /* Like RESTART but also truncate WAL */
9412 
9413 /*
9414 ** CAPI3REF: Virtual Table Interface Configuration
9415 **
9416 ** This function may be called by either the [xConnect] or [xCreate] method
9417 ** of a [virtual table] implementation to configure
9418 ** various facets of the virtual table interface.
9419 **
9420 ** If this interface is invoked outside the context of an xConnect or
9421 ** xCreate virtual table method then the behavior is undefined.
9422 **
9423 ** In the call sqlite3_vtab_config(D,C,...) the D parameter is the
9424 ** [database connection] in which the virtual table is being created and
9425 ** which is passed in as the first argument to the [xConnect] or [xCreate]
9426 ** method that is invoking sqlite3_vtab_config().  The C parameter is one
9427 ** of the [virtual table configuration options].  The presence and meaning
9428 ** of parameters after C depend on which [virtual table configuration option]
9429 ** is used.
9430 */
9431 SQLITE_API int sqlite3_vtab_config(sqlite3*, int op, ...);
9432 
9433 /*
9434 ** CAPI3REF: Virtual Table Configuration Options
9435 ** KEYWORDS: {virtual table configuration options}
9436 ** KEYWORDS: {virtual table configuration option}
9437 **
9438 ** These macros define the various options to the
9439 ** [sqlite3_vtab_config()] interface that [virtual table] implementations
9440 ** can use to customize and optimize their behavior.
9441 **
9442 ** <dl>
9443 ** [[SQLITE_VTAB_CONSTRAINT_SUPPORT]]
9444 ** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT</dt>
9445 ** <dd>Calls of the form
9446 ** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
9447 ** where X is an integer.  If X is zero, then the [virtual table] whose
9448 ** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not
9449 ** support constraints.  In this configuration (which is the default) if
9450 ** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire
9451 ** statement is rolled back as if [ON CONFLICT | OR ABORT] had been
9452 ** specified as part of the users SQL statement, regardless of the actual
9453 ** ON CONFLICT mode specified.
9454 **
9455 ** If X is non-zero, then the virtual table implementation guarantees
9456 ** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before
9457 ** any modifications to internal or persistent data structures have been made.
9458 ** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite
9459 ** is able to roll back a statement or database transaction, and abandon
9460 ** or continue processing the current SQL statement as appropriate.
9461 ** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns
9462 ** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode
9463 ** had been ABORT.
9464 **
9465 ** Virtual table implementations that are required to handle OR REPLACE
9466 ** must do so within the [xUpdate] method. If a call to the
9467 ** [sqlite3_vtab_on_conflict()] function indicates that the current ON
9468 ** CONFLICT policy is REPLACE, the virtual table implementation should
9469 ** silently replace the appropriate rows within the xUpdate callback and
9470 ** return SQLITE_OK. Or, if this is not possible, it may return
9471 ** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT
9472 ** constraint handling.
9473 ** </dd>
9474 **
9475 ** [[SQLITE_VTAB_DIRECTONLY]]<dt>SQLITE_VTAB_DIRECTONLY</dt>
9476 ** <dd>Calls of the form
9477 ** [sqlite3_vtab_config](db,SQLITE_VTAB_DIRECTONLY) from within the
9478 ** the [xConnect] or [xCreate] methods of a [virtual table] implmentation
9479 ** prohibits that virtual table from being used from within triggers and
9480 ** views.
9481 ** </dd>
9482 **
9483 ** [[SQLITE_VTAB_INNOCUOUS]]<dt>SQLITE_VTAB_INNOCUOUS</dt>
9484 ** <dd>Calls of the form
9485 ** [sqlite3_vtab_config](db,SQLITE_VTAB_INNOCUOUS) from within the
9486 ** the [xConnect] or [xCreate] methods of a [virtual table] implmentation
9487 ** identify that virtual table as being safe to use from within triggers
9488 ** and views.  Conceptually, the SQLITE_VTAB_INNOCUOUS tag means that the
9489 ** virtual table can do no serious harm even if it is controlled by a
9490 ** malicious hacker.  Developers should avoid setting the SQLITE_VTAB_INNOCUOUS
9491 ** flag unless absolutely necessary.
9492 ** </dd>
9493 ** </dl>
9494 */
9495 #define SQLITE_VTAB_CONSTRAINT_SUPPORT 1
9496 #define SQLITE_VTAB_INNOCUOUS          2
9497 #define SQLITE_VTAB_DIRECTONLY         3
9498 
9499 /*
9500 ** CAPI3REF: Determine The Virtual Table Conflict Policy
9501 **
9502 ** This function may only be called from within a call to the [xUpdate] method
9503 ** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The
9504 ** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
9505 ** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
9506 ** of the SQL statement that triggered the call to the [xUpdate] method of the
9507 ** [virtual table].
9508 */
9509 SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *);
9510 
9511 /*
9512 ** CAPI3REF: Determine If Virtual Table Column Access Is For UPDATE
9513 **
9514 ** If the sqlite3_vtab_nochange(X) routine is called within the [xColumn]
9515 ** method of a [virtual table], then it might return true if the
9516 ** column is being fetched as part of an UPDATE operation during which the
9517 ** column value will not change.  The virtual table implementation can use
9518 ** this hint as permission to substitute a return value that is less
9519 ** expensive to compute and that the corresponding
9520 ** [xUpdate] method understands as a "no-change" value.
9521 **
9522 ** If the [xColumn] method calls sqlite3_vtab_nochange() and finds that
9523 ** the column is not changed by the UPDATE statement, then the xColumn
9524 ** method can optionally return without setting a result, without calling
9525 ** any of the [sqlite3_result_int|sqlite3_result_xxxxx() interfaces].
9526 ** In that case, [sqlite3_value_nochange(X)] will return true for the
9527 ** same column in the [xUpdate] method.
9528 **
9529 ** The sqlite3_vtab_nochange() routine is an optimization.  Virtual table
9530 ** implementations should continue to give a correct answer even if the
9531 ** sqlite3_vtab_nochange() interface were to always return false.  In the
9532 ** current implementation, the sqlite3_vtab_nochange() interface does always
9533 ** returns false for the enhanced [UPDATE FROM] statement.
9534 */
9535 SQLITE_API int sqlite3_vtab_nochange(sqlite3_context*);
9536 
9537 /*
9538 ** CAPI3REF: Determine The Collation For a Virtual Table Constraint
9539 ** METHOD: sqlite3_index_info
9540 **
9541 ** This function may only be called from within a call to the [xBestIndex]
9542 ** method of a [virtual table].  This function returns a pointer to a string
9543 ** that is the name of the appropriate collation sequence to use for text
9544 ** comparisons on the constraint identified by its arguments.
9545 **
9546 ** The first argument must be the pointer to the [sqlite3_index_info] object
9547 ** that is the first parameter to the xBestIndex() method. The second argument
9548 ** must be an index into the aConstraint[] array belonging to the
9549 ** sqlite3_index_info structure passed to xBestIndex.
9550 **
9551 ** Important:
9552 ** The first parameter must be the same pointer that is passed into the
9553 ** xBestMethod() method.  The first parameter may not be a pointer to a
9554 ** different [sqlite3_index_info] object, even an exact copy.
9555 **
9556 ** The return value is computed as follows:
9557 **
9558 ** <ol>
9559 ** <li><p> If the constraint comes from a WHERE clause expression that contains
9560 **         a [COLLATE operator], then the name of the collation specified by
9561 **         that COLLATE operator is returned.
9562 ** <li><p> If there is no COLLATE operator, but the column that is the subject
9563 **         of the constraint specifies an alternative collating sequence via
9564 **         a [COLLATE clause] on the column definition within the CREATE TABLE
9565 **         statement that was passed into [sqlite3_declare_vtab()], then the
9566 **         name of that alternative collating sequence is returned.
9567 ** <li><p> Otherwise, "BINARY" is returned.
9568 ** </ol>
9569 */
9570 SQLITE_API SQLITE_EXPERIMENTAL const char *sqlite3_vtab_collation(sqlite3_index_info*,int);
9571 
9572 /*
9573 ** CAPI3REF: Determine if a virtual table query is DISTINCT
9574 ** METHOD: sqlite3_index_info
9575 **
9576 ** This API may only be used from within an [xBestIndex|xBestIndex method]
9577 ** of a [virtual table] implementation. The result of calling this
9578 ** interface from outside of xBestIndex() is undefined and probably harmful.
9579 **
9580 ** ^The sqlite3_vtab_distinct() interface returns an integer between 0 and
9581 ** 3.  The integer returned by sqlite3_vtab_distinct()
9582 ** gives the virtual table additional information about how the query
9583 ** planner wants the output to be ordered. As long as the virtual table
9584 ** can meet the ordering requirements of the query planner, it may set
9585 ** the "orderByConsumed" flag.
9586 **
9587 ** <ol><li value="0"><p>
9588 ** ^If the sqlite3_vtab_distinct() interface returns 0, that means
9589 ** that the query planner needs the virtual table to return all rows in the
9590 ** sort order defined by the "nOrderBy" and "aOrderBy" fields of the
9591 ** [sqlite3_index_info] object.  This is the default expectation.  If the
9592 ** virtual table outputs all rows in sorted order, then it is always safe for
9593 ** the xBestIndex method to set the "orderByConsumed" flag, regardless of
9594 ** the return value from sqlite3_vtab_distinct().
9595 ** <li value="1"><p>
9596 ** ^(If the sqlite3_vtab_distinct() interface returns 1, that means
9597 ** that the query planner does not need the rows to be returned in sorted order
9598 ** as long as all rows with the same values in all columns identified by the
9599 ** "aOrderBy" field are adjacent.)^  This mode is used when the query planner
9600 ** is doing a GROUP BY.
9601 ** <li value="2"><p>
9602 ** ^(If the sqlite3_vtab_distinct() interface returns 2, that means
9603 ** that the query planner does not need the rows returned in any particular
9604 ** order, as long as rows with the same values in all "aOrderBy" columns
9605 ** are adjacent.)^  ^(Furthermore, only a single row for each particular
9606 ** combination of values in the columns identified by the "aOrderBy" field
9607 ** needs to be returned.)^  ^It is always ok for two or more rows with the same
9608 ** values in all "aOrderBy" columns to be returned, as long as all such rows
9609 ** are adjacent.  ^The virtual table may, if it chooses, omit extra rows
9610 ** that have the same value for all columns identified by "aOrderBy".
9611 ** ^However omitting the extra rows is optional.
9612 ** This mode is used for a DISTINCT query.
9613 ** <li value="3"><p>
9614 ** ^(If the sqlite3_vtab_distinct() interface returns 3, that means
9615 ** that the query planner needs only distinct rows but it does need the
9616 ** rows to be sorted.)^ ^The virtual table implementation is free to omit
9617 ** rows that are identical in all aOrderBy columns, if it wants to, but
9618 ** it is not required to omit any rows.  This mode is used for queries
9619 ** that have both DISTINCT and ORDER BY clauses.
9620 ** </ol>
9621 **
9622 ** ^For the purposes of comparing virtual table output values to see if the
9623 ** values are same value for sorting purposes, two NULL values are considered
9624 ** to be the same.  In other words, the comparison operator is "IS"
9625 ** (or "IS NOT DISTINCT FROM") and not "==".
9626 **
9627 ** If a virtual table implementation is unable to meet the requirements
9628 ** specified above, then it must not set the "orderByConsumed" flag in the
9629 ** [sqlite3_index_info] object or an incorrect answer may result.
9630 **
9631 ** ^A virtual table implementation is always free to return rows in any order
9632 ** it wants, as long as the "orderByConsumed" flag is not set.  ^When the
9633 ** the "orderByConsumed" flag is unset, the query planner will add extra
9634 ** [bytecode] to ensure that the final results returned by the SQL query are
9635 ** ordered correctly.  The use of the "orderByConsumed" flag and the
9636 ** sqlite3_vtab_distinct() interface is merely an optimization.  ^Careful
9637 ** use of the sqlite3_vtab_distinct() interface and the "orderByConsumed"
9638 ** flag might help queries against a virtual table to run faster.  Being
9639 ** overly aggressive and setting the "orderByConsumed" flag when it is not
9640 ** valid to do so, on the other hand, might cause SQLite to return incorrect
9641 ** results.
9642 */
9643 SQLITE_API int sqlite3_vtab_distinct(sqlite3_index_info*);
9644 
9645 /*
9646 ** CAPI3REF: Identify and handle IN constraints in xBestIndex
9647 **
9648 ** This interface may only be used from within an
9649 ** [xBestIndex|xBestIndex() method] of a [virtual table] implementation.
9650 ** The result of invoking this interface from any other context is
9651 ** undefined and probably harmful.
9652 **
9653 ** ^(A constraint on a virtual table of the form
9654 ** "[IN operator|column IN (...)]" is
9655 ** communicated to the xBestIndex method as a
9656 ** [SQLITE_INDEX_CONSTRAINT_EQ] constraint.)^  If xBestIndex wants to use
9657 ** this constraint, it must set the corresponding
9658 ** aConstraintUsage[].argvIndex to a postive integer.  ^(Then, under
9659 ** the usual mode of handling IN operators, SQLite generates [bytecode]
9660 ** that invokes the [xFilter|xFilter() method] once for each value
9661 ** on the right-hand side of the IN operator.)^  Thus the virtual table
9662 ** only sees a single value from the right-hand side of the IN operator
9663 ** at a time.
9664 **
9665 ** In some cases, however, it would be advantageous for the virtual
9666 ** table to see all values on the right-hand of the IN operator all at
9667 ** once.  The sqlite3_vtab_in() interfaces facilitates this in two ways:
9668 **
9669 ** <ol>
9670 ** <li><p>
9671 **   ^A call to sqlite3_vtab_in(P,N,-1) will return true (non-zero)
9672 **   if and only if the [sqlite3_index_info|P->aConstraint][N] constraint
9673 **   is an [IN operator] that can be processed all at once.  ^In other words,
9674 **   sqlite3_vtab_in() with -1 in the third argument is a mechanism
9675 **   by which the virtual table can ask SQLite if all-at-once processing
9676 **   of the IN operator is even possible.
9677 **
9678 ** <li><p>
9679 **   ^A call to sqlite3_vtab_in(P,N,F) with F==1 or F==0 indicates
9680 **   to SQLite that the virtual table does or does not want to process
9681 **   the IN operator all-at-once, respectively.  ^Thus when the third
9682 **   parameter (F) is non-negative, this interface is the mechanism by
9683 **   which the virtual table tells SQLite how it wants to process the
9684 **   IN operator.
9685 ** </ol>
9686 **
9687 ** ^The sqlite3_vtab_in(P,N,F) interface can be invoked multiple times
9688 ** within the same xBestIndex method call.  ^For any given P,N pair,
9689 ** the return value from sqlite3_vtab_in(P,N,F) will always be the same
9690 ** within the same xBestIndex call.  ^If the interface returns true
9691 ** (non-zero), that means that the constraint is an IN operator
9692 ** that can be processed all-at-once.  ^If the constraint is not an IN
9693 ** operator or cannot be processed all-at-once, then the interface returns
9694 ** false.
9695 **
9696 ** ^(All-at-once processing of the IN operator is selected if both of the
9697 ** following conditions are met:
9698 **
9699 ** <ol>
9700 ** <li><p> The P->aConstraintUsage[N].argvIndex value is set to a positive
9701 ** integer.  This is how the virtual table tells SQLite that it wants to
9702 ** use the N-th constraint.
9703 **
9704 ** <li><p> The last call to sqlite3_vtab_in(P,N,F) for which F was
9705 ** non-negative had F>=1.
9706 ** </ol>)^
9707 **
9708 ** ^If either or both of the conditions above are false, then SQLite uses
9709 ** the traditional one-at-a-time processing strategy for the IN constraint.
9710 ** ^If both conditions are true, then the argvIndex-th parameter to the
9711 ** xFilter method will be an [sqlite3_value] that appears to be NULL,
9712 ** but which can be passed to [sqlite3_vtab_in_first()] and
9713 ** [sqlite3_vtab_in_next()] to find all values on the right-hand side
9714 ** of the IN constraint.
9715 */
9716 SQLITE_API int sqlite3_vtab_in(sqlite3_index_info*, int iCons, int bHandle);
9717 
9718 /*
9719 ** CAPI3REF: Find all elements on the right-hand side of an IN constraint.
9720 **
9721 ** These interfaces are only useful from within the
9722 ** [xFilter|xFilter() method] of a [virtual table] implementation.
9723 ** The result of invoking these interfaces from any other context
9724 ** is undefined and probably harmful.
9725 **
9726 ** The X parameter in a call to sqlite3_vtab_in_first(X,P) or
9727 ** sqlite3_vtab_in_next(X,P) must be one of the parameters to the
9728 ** xFilter method which invokes these routines, and specifically
9729 ** a parameter that was previously selected for all-at-once IN constraint
9730 ** processing use the [sqlite3_vtab_in()] interface in the
9731 ** [xBestIndex|xBestIndex method].  ^(If the X parameter is not
9732 ** an xFilter argument that was selected for all-at-once IN constraint
9733 ** processing, then these routines return [SQLITE_MISUSE])^ or perhaps
9734 ** exhibit some other undefined or harmful behavior.
9735 **
9736 ** ^(Use these routines to access all values on the right-hand side
9737 ** of the IN constraint using code like the following:
9738 **
9739 ** <blockquote><pre>
9740 ** &nbsp;  for(rc=sqlite3_vtab_in_first(pList, &pVal);
9741 ** &nbsp;      rc==SQLITE_OK && pVal
9742 ** &nbsp;      rc=sqlite3_vtab_in_next(pList, &pVal)
9743 ** &nbsp;  ){
9744 ** &nbsp;    // do something with pVal
9745 ** &nbsp;  }
9746 ** &nbsp;  if( rc!=SQLITE_OK ){
9747 ** &nbsp;    // an error has occurred
9748 ** &nbsp;  }
9749 ** </pre></blockquote>)^
9750 **
9751 ** ^On success, the sqlite3_vtab_in_first(X,P) and sqlite3_vtab_in_next(X,P)
9752 ** routines return SQLITE_OK and set *P to point to the first or next value
9753 ** on the RHS of the IN constraint.  ^If there are no more values on the
9754 ** right hand side of the IN constraint, then *P is set to NULL and these
9755 ** routines return [SQLITE_DONE].  ^The return value might be
9756 ** some other value, such as SQLITE_NOMEM, in the event of a malfunction.
9757 **
9758 ** The *ppOut values returned by these routines are only valid until the
9759 ** next call to either of these routines or until the end of the xFilter
9760 ** method from which these routines were called.  If the virtual table
9761 ** implementation needs to retain the *ppOut values for longer, it must make
9762 ** copies.  The *ppOut values are [protected sqlite3_value|protected].
9763 */
9764 SQLITE_API int sqlite3_vtab_in_first(sqlite3_value *pVal, sqlite3_value **ppOut);
9765 SQLITE_API int sqlite3_vtab_in_next(sqlite3_value *pVal, sqlite3_value **ppOut);
9766 
9767 /*
9768 ** CAPI3REF: Constraint values in xBestIndex()
9769 ** METHOD: sqlite3_index_info
9770 **
9771 ** This API may only be used from within the [xBestIndex|xBestIndex method]
9772 ** of a [virtual table] implementation. The result of calling this interface
9773 ** from outside of an xBestIndex method are undefined and probably harmful.
9774 **
9775 ** ^When the sqlite3_vtab_rhs_value(P,J,V) interface is invoked from within
9776 ** the [xBestIndex] method of a [virtual table] implementation, with P being
9777 ** a copy of the [sqlite3_index_info] object pointer passed into xBestIndex and
9778 ** J being a 0-based index into P->aConstraint[], then this routine
9779 ** attempts to set *V to the value of the right-hand operand of
9780 ** that constraint if the right-hand operand is known.  ^If the
9781 ** right-hand operand is not known, then *V is set to a NULL pointer.
9782 ** ^The sqlite3_vtab_rhs_value(P,J,V) interface returns SQLITE_OK if
9783 ** and only if *V is set to a value.  ^The sqlite3_vtab_rhs_value(P,J,V)
9784 ** inteface returns SQLITE_NOTFOUND if the right-hand side of the J-th
9785 ** constraint is not available.  ^The sqlite3_vtab_rhs_value() interface
9786 ** can return an result code other than SQLITE_OK or SQLITE_NOTFOUND if
9787 ** something goes wrong.
9788 **
9789 ** The sqlite3_vtab_rhs_value() interface is usually only successful if
9790 ** the right-hand operand of a constraint is a literal value in the original
9791 ** SQL statement.  If the right-hand operand is an expression or a reference
9792 ** to some other column or a [host parameter], then sqlite3_vtab_rhs_value()
9793 ** will probably return [SQLITE_NOTFOUND].
9794 **
9795 ** ^(Some constraints, such as [SQLITE_INDEX_CONSTRAINT_ISNULL] and
9796 ** [SQLITE_INDEX_CONSTRAINT_ISNOTNULL], have no right-hand operand.  For such
9797 ** constraints, sqlite3_vtab_rhs_value() always returns SQLITE_NOTFOUND.)^
9798 **
9799 ** ^The [sqlite3_value] object returned in *V is a protected sqlite3_value
9800 ** and remains valid for the duration of the xBestIndex method call.
9801 ** ^When xBestIndex returns, the sqlite3_value object returned by
9802 ** sqlite3_vtab_rhs_value() is automatically deallocated.
9803 **
9804 ** The "_rhs_" in the name of this routine is an abbreviation for
9805 ** "Right-Hand Side".
9806 */
9807 SQLITE_API int sqlite3_vtab_rhs_value(sqlite3_index_info*, int, sqlite3_value **ppVal);
9808 
9809 /*
9810 ** CAPI3REF: Conflict resolution modes
9811 ** KEYWORDS: {conflict resolution mode}
9812 **
9813 ** These constants are returned by [sqlite3_vtab_on_conflict()] to
9814 ** inform a [virtual table] implementation what the [ON CONFLICT] mode
9815 ** is for the SQL statement being evaluated.
9816 **
9817 ** Note that the [SQLITE_IGNORE] constant is also used as a potential
9818 ** return value from the [sqlite3_set_authorizer()] callback and that
9819 ** [SQLITE_ABORT] is also a [result code].
9820 */
9821 #define SQLITE_ROLLBACK 1
9822 /* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
9823 #define SQLITE_FAIL     3
9824 /* #define SQLITE_ABORT 4  // Also an error code */
9825 #define SQLITE_REPLACE  5
9826 
9827 /*
9828 ** CAPI3REF: Prepared Statement Scan Status Opcodes
9829 ** KEYWORDS: {scanstatus options}
9830 **
9831 ** The following constants can be used for the T parameter to the
9832 ** [sqlite3_stmt_scanstatus(S,X,T,V)] interface.  Each constant designates a
9833 ** different metric for sqlite3_stmt_scanstatus() to return.
9834 **
9835 ** When the value returned to V is a string, space to hold that string is
9836 ** managed by the prepared statement S and will be automatically freed when
9837 ** S is finalized.
9838 **
9839 ** <dl>
9840 ** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt>
9841 ** <dd>^The [sqlite3_int64] variable pointed to by the V parameter will be
9842 ** set to the total number of times that the X-th loop has run.</dd>
9843 **
9844 ** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt>
9845 ** <dd>^The [sqlite3_int64] variable pointed to by the V parameter will be set
9846 ** to the total number of rows examined by all iterations of the X-th loop.</dd>
9847 **
9848 ** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt>
9849 ** <dd>^The "double" variable pointed to by the V parameter will be set to the
9850 ** query planner's estimate for the average number of rows output from each
9851 ** iteration of the X-th loop.  If the query planner's estimates was accurate,
9852 ** then this value will approximate the quotient NVISIT/NLOOP and the
9853 ** product of this value for all prior loops with the same SELECTID will
9854 ** be the NLOOP value for the current loop.
9855 **
9856 ** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt>
9857 ** <dd>^The "const char *" variable pointed to by the V parameter will be set
9858 ** to a zero-terminated UTF-8 string containing the name of the index or table
9859 ** used for the X-th loop.
9860 **
9861 ** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt>
9862 ** <dd>^The "const char *" variable pointed to by the V parameter will be set
9863 ** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN]
9864 ** description for the X-th loop.
9865 **
9866 ** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt>
9867 ** <dd>^The "int" variable pointed to by the V parameter will be set to the
9868 ** "select-id" for the X-th loop.  The select-id identifies which query or
9869 ** subquery the loop is part of.  The main query has a select-id of zero.
9870 ** The select-id is the same value as is output in the first column
9871 ** of an [EXPLAIN QUERY PLAN] query.
9872 ** </dl>
9873 */
9874 #define SQLITE_SCANSTAT_NLOOP    0
9875 #define SQLITE_SCANSTAT_NVISIT   1
9876 #define SQLITE_SCANSTAT_EST      2
9877 #define SQLITE_SCANSTAT_NAME     3
9878 #define SQLITE_SCANSTAT_EXPLAIN  4
9879 #define SQLITE_SCANSTAT_SELECTID 5
9880 
9881 /*
9882 ** CAPI3REF: Prepared Statement Scan Status
9883 ** METHOD: sqlite3_stmt
9884 **
9885 ** This interface returns information about the predicted and measured
9886 ** performance for pStmt.  Advanced applications can use this
9887 ** interface to compare the predicted and the measured performance and
9888 ** issue warnings and/or rerun [ANALYZE] if discrepancies are found.
9889 **
9890 ** Since this interface is expected to be rarely used, it is only
9891 ** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS]
9892 ** compile-time option.
9893 **
9894 ** The "iScanStatusOp" parameter determines which status information to return.
9895 ** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior
9896 ** of this interface is undefined.
9897 ** ^The requested measurement is written into a variable pointed to by
9898 ** the "pOut" parameter.
9899 ** Parameter "idx" identifies the specific loop to retrieve statistics for.
9900 ** Loops are numbered starting from zero. ^If idx is out of range - less than
9901 ** zero or greater than or equal to the total number of loops used to implement
9902 ** the statement - a non-zero value is returned and the variable that pOut
9903 ** points to is unchanged.
9904 **
9905 ** ^Statistics might not be available for all loops in all statements. ^In cases
9906 ** where there exist loops with no available statistics, this function behaves
9907 ** as if the loop did not exist - it returns non-zero and leave the variable
9908 ** that pOut points to unchanged.
9909 **
9910 ** See also: [sqlite3_stmt_scanstatus_reset()]
9911 */
9912 SQLITE_API int sqlite3_stmt_scanstatus(
9913   sqlite3_stmt *pStmt,      /* Prepared statement for which info desired */
9914   int idx,                  /* Index of loop to report on */
9915   int iScanStatusOp,        /* Information desired.  SQLITE_SCANSTAT_* */
9916   void *pOut                /* Result written here */
9917 );
9918 
9919 /*
9920 ** CAPI3REF: Zero Scan-Status Counters
9921 ** METHOD: sqlite3_stmt
9922 **
9923 ** ^Zero all [sqlite3_stmt_scanstatus()] related event counters.
9924 **
9925 ** This API is only available if the library is built with pre-processor
9926 ** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined.
9927 */
9928 SQLITE_API void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*);
9929 
9930 /*
9931 ** CAPI3REF: Flush caches to disk mid-transaction
9932 ** METHOD: sqlite3
9933 **
9934 ** ^If a write-transaction is open on [database connection] D when the
9935 ** [sqlite3_db_cacheflush(D)] interface invoked, any dirty
9936 ** pages in the pager-cache that are not currently in use are written out
9937 ** to disk. A dirty page may be in use if a database cursor created by an
9938 ** active SQL statement is reading from it, or if it is page 1 of a database
9939 ** file (page 1 is always "in use").  ^The [sqlite3_db_cacheflush(D)]
9940 ** interface flushes caches for all schemas - "main", "temp", and
9941 ** any [attached] databases.
9942 **
9943 ** ^If this function needs to obtain extra database locks before dirty pages
9944 ** can be flushed to disk, it does so. ^If those locks cannot be obtained
9945 ** immediately and there is a busy-handler callback configured, it is invoked
9946 ** in the usual manner. ^If the required lock still cannot be obtained, then
9947 ** the database is skipped and an attempt made to flush any dirty pages
9948 ** belonging to the next (if any) database. ^If any databases are skipped
9949 ** because locks cannot be obtained, but no other error occurs, this
9950 ** function returns SQLITE_BUSY.
9951 **
9952 ** ^If any other error occurs while flushing dirty pages to disk (for
9953 ** example an IO error or out-of-memory condition), then processing is
9954 ** abandoned and an SQLite [error code] is returned to the caller immediately.
9955 **
9956 ** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK.
9957 **
9958 ** ^This function does not set the database handle error code or message
9959 ** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions.
9960 */
9961 SQLITE_API int sqlite3_db_cacheflush(sqlite3*);
9962 
9963 /*
9964 ** CAPI3REF: The pre-update hook.
9965 ** METHOD: sqlite3
9966 **
9967 ** ^These interfaces are only available if SQLite is compiled using the
9968 ** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option.
9969 **
9970 ** ^The [sqlite3_preupdate_hook()] interface registers a callback function
9971 ** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation
9972 ** on a database table.
9973 ** ^At most one preupdate hook may be registered at a time on a single
9974 ** [database connection]; each call to [sqlite3_preupdate_hook()] overrides
9975 ** the previous setting.
9976 ** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()]
9977 ** with a NULL pointer as the second parameter.
9978 ** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as
9979 ** the first parameter to callbacks.
9980 **
9981 ** ^The preupdate hook only fires for changes to real database tables; the
9982 ** preupdate hook is not invoked for changes to [virtual tables] or to
9983 ** system tables like sqlite_sequence or sqlite_stat1.
9984 **
9985 ** ^The second parameter to the preupdate callback is a pointer to
9986 ** the [database connection] that registered the preupdate hook.
9987 ** ^The third parameter to the preupdate callback is one of the constants
9988 ** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the
9989 ** kind of update operation that is about to occur.
9990 ** ^(The fourth parameter to the preupdate callback is the name of the
9991 ** database within the database connection that is being modified.  This
9992 ** will be "main" for the main database or "temp" for TEMP tables or
9993 ** the name given after the AS keyword in the [ATTACH] statement for attached
9994 ** databases.)^
9995 ** ^The fifth parameter to the preupdate callback is the name of the
9996 ** table that is being modified.
9997 **
9998 ** For an UPDATE or DELETE operation on a [rowid table], the sixth
9999 ** parameter passed to the preupdate callback is the initial [rowid] of the
10000 ** row being modified or deleted. For an INSERT operation on a rowid table,
10001 ** or any operation on a WITHOUT ROWID table, the value of the sixth
10002 ** parameter is undefined. For an INSERT or UPDATE on a rowid table the
10003 ** seventh parameter is the final rowid value of the row being inserted
10004 ** or updated. The value of the seventh parameter passed to the callback
10005 ** function is not defined for operations on WITHOUT ROWID tables, or for
10006 ** DELETE operations on rowid tables.
10007 **
10008 ** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()],
10009 ** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces
10010 ** provide additional information about a preupdate event. These routines
10011 ** may only be called from within a preupdate callback.  Invoking any of
10012 ** these routines from outside of a preupdate callback or with a
10013 ** [database connection] pointer that is different from the one supplied
10014 ** to the preupdate callback results in undefined and probably undesirable
10015 ** behavior.
10016 **
10017 ** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns
10018 ** in the row that is being inserted, updated, or deleted.
10019 **
10020 ** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to
10021 ** a [protected sqlite3_value] that contains the value of the Nth column of
10022 ** the table row before it is updated.  The N parameter must be between 0
10023 ** and one less than the number of columns or the behavior will be
10024 ** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE
10025 ** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the
10026 ** behavior is undefined.  The [sqlite3_value] that P points to
10027 ** will be destroyed when the preupdate callback returns.
10028 **
10029 ** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to
10030 ** a [protected sqlite3_value] that contains the value of the Nth column of
10031 ** the table row after it is updated.  The N parameter must be between 0
10032 ** and one less than the number of columns or the behavior will be
10033 ** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE
10034 ** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the
10035 ** behavior is undefined.  The [sqlite3_value] that P points to
10036 ** will be destroyed when the preupdate callback returns.
10037 **
10038 ** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate
10039 ** callback was invoked as a result of a direct insert, update, or delete
10040 ** operation; or 1 for inserts, updates, or deletes invoked by top-level
10041 ** triggers; or 2 for changes resulting from triggers called by top-level
10042 ** triggers; and so forth.
10043 **
10044 ** When the [sqlite3_blob_write()] API is used to update a blob column,
10045 ** the pre-update hook is invoked with SQLITE_DELETE. This is because the
10046 ** in this case the new values are not available. In this case, when a
10047 ** callback made with op==SQLITE_DELETE is actuall a write using the
10048 ** sqlite3_blob_write() API, the [sqlite3_preupdate_blobwrite()] returns
10049 ** the index of the column being written. In other cases, where the
10050 ** pre-update hook is being invoked for some other reason, including a
10051 ** regular DELETE, sqlite3_preupdate_blobwrite() returns -1.
10052 **
10053 ** See also:  [sqlite3_update_hook()]
10054 */
10055 #if defined(SQLITE_ENABLE_PREUPDATE_HOOK)
10056 SQLITE_API void *sqlite3_preupdate_hook(
10057   sqlite3 *db,
10058   void(*xPreUpdate)(
10059     void *pCtx,                   /* Copy of third arg to preupdate_hook() */
10060     sqlite3 *db,                  /* Database handle */
10061     int op,                       /* SQLITE_UPDATE, DELETE or INSERT */
10062     char const *zDb,              /* Database name */
10063     char const *zName,            /* Table name */
10064     sqlite3_int64 iKey1,          /* Rowid of row about to be deleted/updated */
10065     sqlite3_int64 iKey2           /* New rowid value (for a rowid UPDATE) */
10066   ),
10067   void*
10068 );
10069 SQLITE_API int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **);
10070 SQLITE_API int sqlite3_preupdate_count(sqlite3 *);
10071 SQLITE_API int sqlite3_preupdate_depth(sqlite3 *);
10072 SQLITE_API int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **);
10073 SQLITE_API int sqlite3_preupdate_blobwrite(sqlite3 *);
10074 #endif
10075 
10076 /*
10077 ** CAPI3REF: Low-level system error code
10078 ** METHOD: sqlite3
10079 **
10080 ** ^Attempt to return the underlying operating system error code or error
10081 ** number that caused the most recent I/O error or failure to open a file.
10082 ** The return value is OS-dependent.  For example, on unix systems, after
10083 ** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be
10084 ** called to get back the underlying "errno" that caused the problem, such
10085 ** as ENOSPC, EAUTH, EISDIR, and so forth.
10086 */
10087 SQLITE_API int sqlite3_system_errno(sqlite3*);
10088 
10089 /*
10090 ** CAPI3REF: Database Snapshot
10091 ** KEYWORDS: {snapshot} {sqlite3_snapshot}
10092 **
10093 ** An instance of the snapshot object records the state of a [WAL mode]
10094 ** database for some specific point in history.
10095 **
10096 ** In [WAL mode], multiple [database connections] that are open on the
10097 ** same database file can each be reading a different historical version
10098 ** of the database file.  When a [database connection] begins a read
10099 ** transaction, that connection sees an unchanging copy of the database
10100 ** as it existed for the point in time when the transaction first started.
10101 ** Subsequent changes to the database from other connections are not seen
10102 ** by the reader until a new read transaction is started.
10103 **
10104 ** The sqlite3_snapshot object records state information about an historical
10105 ** version of the database file so that it is possible to later open a new read
10106 ** transaction that sees that historical version of the database rather than
10107 ** the most recent version.
10108 */
10109 typedef struct sqlite3_snapshot {
10110   unsigned char hidden[48];
10111 } sqlite3_snapshot;
10112 
10113 /*
10114 ** CAPI3REF: Record A Database Snapshot
10115 ** CONSTRUCTOR: sqlite3_snapshot
10116 **
10117 ** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a
10118 ** new [sqlite3_snapshot] object that records the current state of
10119 ** schema S in database connection D.  ^On success, the
10120 ** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly
10121 ** created [sqlite3_snapshot] object into *P and returns SQLITE_OK.
10122 ** If there is not already a read-transaction open on schema S when
10123 ** this function is called, one is opened automatically.
10124 **
10125 ** The following must be true for this function to succeed. If any of
10126 ** the following statements are false when sqlite3_snapshot_get() is
10127 ** called, SQLITE_ERROR is returned. The final value of *P is undefined
10128 ** in this case.
10129 **
10130 ** <ul>
10131 **   <li> The database handle must not be in [autocommit mode].
10132 **
10133 **   <li> Schema S of [database connection] D must be a [WAL mode] database.
10134 **
10135 **   <li> There must not be a write transaction open on schema S of database
10136 **        connection D.
10137 **
10138 **   <li> One or more transactions must have been written to the current wal
10139 **        file since it was created on disk (by any connection). This means
10140 **        that a snapshot cannot be taken on a wal mode database with no wal
10141 **        file immediately after it is first opened. At least one transaction
10142 **        must be written to it first.
10143 ** </ul>
10144 **
10145 ** This function may also return SQLITE_NOMEM.  If it is called with the
10146 ** database handle in autocommit mode but fails for some other reason,
10147 ** whether or not a read transaction is opened on schema S is undefined.
10148 **
10149 ** The [sqlite3_snapshot] object returned from a successful call to
10150 ** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()]
10151 ** to avoid a memory leak.
10152 **
10153 ** The [sqlite3_snapshot_get()] interface is only available when the
10154 ** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
10155 */
10156 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_get(
10157   sqlite3 *db,
10158   const char *zSchema,
10159   sqlite3_snapshot **ppSnapshot
10160 );
10161 
10162 /*
10163 ** CAPI3REF: Start a read transaction on an historical snapshot
10164 ** METHOD: sqlite3_snapshot
10165 **
10166 ** ^The [sqlite3_snapshot_open(D,S,P)] interface either starts a new read
10167 ** transaction or upgrades an existing one for schema S of
10168 ** [database connection] D such that the read transaction refers to
10169 ** historical [snapshot] P, rather than the most recent change to the
10170 ** database. ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK
10171 ** on success or an appropriate [error code] if it fails.
10172 **
10173 ** ^In order to succeed, the database connection must not be in
10174 ** [autocommit mode] when [sqlite3_snapshot_open(D,S,P)] is called. If there
10175 ** is already a read transaction open on schema S, then the database handle
10176 ** must have no active statements (SELECT statements that have been passed
10177 ** to sqlite3_step() but not sqlite3_reset() or sqlite3_finalize()).
10178 ** SQLITE_ERROR is returned if either of these conditions is violated, or
10179 ** if schema S does not exist, or if the snapshot object is invalid.
10180 **
10181 ** ^A call to sqlite3_snapshot_open() will fail to open if the specified
10182 ** snapshot has been overwritten by a [checkpoint]. In this case
10183 ** SQLITE_ERROR_SNAPSHOT is returned.
10184 **
10185 ** If there is already a read transaction open when this function is
10186 ** invoked, then the same read transaction remains open (on the same
10187 ** database snapshot) if SQLITE_ERROR, SQLITE_BUSY or SQLITE_ERROR_SNAPSHOT
10188 ** is returned. If another error code - for example SQLITE_PROTOCOL or an
10189 ** SQLITE_IOERR error code - is returned, then the final state of the
10190 ** read transaction is undefined. If SQLITE_OK is returned, then the
10191 ** read transaction is now open on database snapshot P.
10192 **
10193 ** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the
10194 ** database connection D does not know that the database file for
10195 ** schema S is in [WAL mode].  A database connection might not know
10196 ** that the database file is in [WAL mode] if there has been no prior
10197 ** I/O on that database connection, or if the database entered [WAL mode]
10198 ** after the most recent I/O on the database connection.)^
10199 ** (Hint: Run "[PRAGMA application_id]" against a newly opened
10200 ** database connection in order to make it ready to use snapshots.)
10201 **
10202 ** The [sqlite3_snapshot_open()] interface is only available when the
10203 ** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
10204 */
10205 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_open(
10206   sqlite3 *db,
10207   const char *zSchema,
10208   sqlite3_snapshot *pSnapshot
10209 );
10210 
10211 /*
10212 ** CAPI3REF: Destroy a snapshot
10213 ** DESTRUCTOR: sqlite3_snapshot
10214 **
10215 ** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P.
10216 ** The application must eventually free every [sqlite3_snapshot] object
10217 ** using this routine to avoid a memory leak.
10218 **
10219 ** The [sqlite3_snapshot_free()] interface is only available when the
10220 ** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
10221 */
10222 SQLITE_API SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*);
10223 
10224 /*
10225 ** CAPI3REF: Compare the ages of two snapshot handles.
10226 ** METHOD: sqlite3_snapshot
10227 **
10228 ** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages
10229 ** of two valid snapshot handles.
10230 **
10231 ** If the two snapshot handles are not associated with the same database
10232 ** file, the result of the comparison is undefined.
10233 **
10234 ** Additionally, the result of the comparison is only valid if both of the
10235 ** snapshot handles were obtained by calling sqlite3_snapshot_get() since the
10236 ** last time the wal file was deleted. The wal file is deleted when the
10237 ** database is changed back to rollback mode or when the number of database
10238 ** clients drops to zero. If either snapshot handle was obtained before the
10239 ** wal file was last deleted, the value returned by this function
10240 ** is undefined.
10241 **
10242 ** Otherwise, this API returns a negative value if P1 refers to an older
10243 ** snapshot than P2, zero if the two handles refer to the same database
10244 ** snapshot, and a positive value if P1 is a newer snapshot than P2.
10245 **
10246 ** This interface is only available if SQLite is compiled with the
10247 ** [SQLITE_ENABLE_SNAPSHOT] option.
10248 */
10249 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp(
10250   sqlite3_snapshot *p1,
10251   sqlite3_snapshot *p2
10252 );
10253 
10254 /*
10255 ** CAPI3REF: Recover snapshots from a wal file
10256 ** METHOD: sqlite3_snapshot
10257 **
10258 ** If a [WAL file] remains on disk after all database connections close
10259 ** (either through the use of the [SQLITE_FCNTL_PERSIST_WAL] [file control]
10260 ** or because the last process to have the database opened exited without
10261 ** calling [sqlite3_close()]) and a new connection is subsequently opened
10262 ** on that database and [WAL file], the [sqlite3_snapshot_open()] interface
10263 ** will only be able to open the last transaction added to the WAL file
10264 ** even though the WAL file contains other valid transactions.
10265 **
10266 ** This function attempts to scan the WAL file associated with database zDb
10267 ** of database handle db and make all valid snapshots available to
10268 ** sqlite3_snapshot_open(). It is an error if there is already a read
10269 ** transaction open on the database, or if the database is not a WAL mode
10270 ** database.
10271 **
10272 ** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
10273 **
10274 ** This interface is only available if SQLite is compiled with the
10275 ** [SQLITE_ENABLE_SNAPSHOT] option.
10276 */
10277 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb);
10278 
10279 /*
10280 ** CAPI3REF: Serialize a database
10281 **
10282 ** The sqlite3_serialize(D,S,P,F) interface returns a pointer to memory
10283 ** that is a serialization of the S database on [database connection] D.
10284 ** If P is not a NULL pointer, then the size of the database in bytes
10285 ** is written into *P.
10286 **
10287 ** For an ordinary on-disk database file, the serialization is just a
10288 ** copy of the disk file.  For an in-memory database or a "TEMP" database,
10289 ** the serialization is the same sequence of bytes which would be written
10290 ** to disk if that database where backed up to disk.
10291 **
10292 ** The usual case is that sqlite3_serialize() copies the serialization of
10293 ** the database into memory obtained from [sqlite3_malloc64()] and returns
10294 ** a pointer to that memory.  The caller is responsible for freeing the
10295 ** returned value to avoid a memory leak.  However, if the F argument
10296 ** contains the SQLITE_SERIALIZE_NOCOPY bit, then no memory allocations
10297 ** are made, and the sqlite3_serialize() function will return a pointer
10298 ** to the contiguous memory representation of the database that SQLite
10299 ** is currently using for that database, or NULL if the no such contiguous
10300 ** memory representation of the database exists.  A contiguous memory
10301 ** representation of the database will usually only exist if there has
10302 ** been a prior call to [sqlite3_deserialize(D,S,...)] with the same
10303 ** values of D and S.
10304 ** The size of the database is written into *P even if the
10305 ** SQLITE_SERIALIZE_NOCOPY bit is set but no contiguous copy
10306 ** of the database exists.
10307 **
10308 ** A call to sqlite3_serialize(D,S,P,F) might return NULL even if the
10309 ** SQLITE_SERIALIZE_NOCOPY bit is omitted from argument F if a memory
10310 ** allocation error occurs.
10311 **
10312 ** This interface is omitted if SQLite is compiled with the
10313 ** [SQLITE_OMIT_DESERIALIZE] option.
10314 */
10315 SQLITE_API unsigned char *sqlite3_serialize(
10316   sqlite3 *db,           /* The database connection */
10317   const char *zSchema,   /* Which DB to serialize. ex: "main", "temp", ... */
10318   sqlite3_int64 *piSize, /* Write size of the DB here, if not NULL */
10319   unsigned int mFlags    /* Zero or more SQLITE_SERIALIZE_* flags */
10320 );
10321 
10322 /*
10323 ** CAPI3REF: Flags for sqlite3_serialize
10324 **
10325 ** Zero or more of the following constants can be OR-ed together for
10326 ** the F argument to [sqlite3_serialize(D,S,P,F)].
10327 **
10328 ** SQLITE_SERIALIZE_NOCOPY means that [sqlite3_serialize()] will return
10329 ** a pointer to contiguous in-memory database that it is currently using,
10330 ** without making a copy of the database.  If SQLite is not currently using
10331 ** a contiguous in-memory database, then this option causes
10332 ** [sqlite3_serialize()] to return a NULL pointer.  SQLite will only be
10333 ** using a contiguous in-memory database if it has been initialized by a
10334 ** prior call to [sqlite3_deserialize()].
10335 */
10336 #define SQLITE_SERIALIZE_NOCOPY 0x001   /* Do no memory allocations */
10337 
10338 /*
10339 ** CAPI3REF: Deserialize a database
10340 **
10341 ** The sqlite3_deserialize(D,S,P,N,M,F) interface causes the
10342 ** [database connection] D to disconnect from database S and then
10343 ** reopen S as an in-memory database based on the serialization contained
10344 ** in P.  The serialized database P is N bytes in size.  M is the size of
10345 ** the buffer P, which might be larger than N.  If M is larger than N, and
10346 ** the SQLITE_DESERIALIZE_READONLY bit is not set in F, then SQLite is
10347 ** permitted to add content to the in-memory database as long as the total
10348 ** size does not exceed M bytes.
10349 **
10350 ** If the SQLITE_DESERIALIZE_FREEONCLOSE bit is set in F, then SQLite will
10351 ** invoke sqlite3_free() on the serialization buffer when the database
10352 ** connection closes.  If the SQLITE_DESERIALIZE_RESIZEABLE bit is set, then
10353 ** SQLite will try to increase the buffer size using sqlite3_realloc64()
10354 ** if writes on the database cause it to grow larger than M bytes.
10355 **
10356 ** The sqlite3_deserialize() interface will fail with SQLITE_BUSY if the
10357 ** database is currently in a read transaction or is involved in a backup
10358 ** operation.
10359 **
10360 ** It is not possible to deserialized into the TEMP database.  If the
10361 ** S argument to sqlite3_deserialize(D,S,P,N,M,F) is "temp" then the
10362 ** function returns SQLITE_ERROR.
10363 **
10364 ** If sqlite3_deserialize(D,S,P,N,M,F) fails for any reason and if the
10365 ** SQLITE_DESERIALIZE_FREEONCLOSE bit is set in argument F, then
10366 ** [sqlite3_free()] is invoked on argument P prior to returning.
10367 **
10368 ** This interface is omitted if SQLite is compiled with the
10369 ** [SQLITE_OMIT_DESERIALIZE] option.
10370 */
10371 SQLITE_API int sqlite3_deserialize(
10372   sqlite3 *db,            /* The database connection */
10373   const char *zSchema,    /* Which DB to reopen with the deserialization */
10374   unsigned char *pData,   /* The serialized database content */
10375   sqlite3_int64 szDb,     /* Number bytes in the deserialization */
10376   sqlite3_int64 szBuf,    /* Total size of buffer pData[] */
10377   unsigned mFlags         /* Zero or more SQLITE_DESERIALIZE_* flags */
10378 );
10379 
10380 /*
10381 ** CAPI3REF: Flags for sqlite3_deserialize()
10382 **
10383 ** The following are allowed values for 6th argument (the F argument) to
10384 ** the [sqlite3_deserialize(D,S,P,N,M,F)] interface.
10385 **
10386 ** The SQLITE_DESERIALIZE_FREEONCLOSE means that the database serialization
10387 ** in the P argument is held in memory obtained from [sqlite3_malloc64()]
10388 ** and that SQLite should take ownership of this memory and automatically
10389 ** free it when it has finished using it.  Without this flag, the caller
10390 ** is responsible for freeing any dynamically allocated memory.
10391 **
10392 ** The SQLITE_DESERIALIZE_RESIZEABLE flag means that SQLite is allowed to
10393 ** grow the size of the database using calls to [sqlite3_realloc64()].  This
10394 ** flag should only be used if SQLITE_DESERIALIZE_FREEONCLOSE is also used.
10395 ** Without this flag, the deserialized database cannot increase in size beyond
10396 ** the number of bytes specified by the M parameter.
10397 **
10398 ** The SQLITE_DESERIALIZE_READONLY flag means that the deserialized database
10399 ** should be treated as read-only.
10400 */
10401 #define SQLITE_DESERIALIZE_FREEONCLOSE 1 /* Call sqlite3_free() on close */
10402 #define SQLITE_DESERIALIZE_RESIZEABLE  2 /* Resize using sqlite3_realloc64() */
10403 #define SQLITE_DESERIALIZE_READONLY    4 /* Database is read-only */
10404 
10405 /*
10406 ** Undo the hack that converts floating point types to integer for
10407 ** builds on processors without floating point support.
10408 */
10409 #ifdef SQLITE_OMIT_FLOATING_POINT
10410 # undef double
10411 #endif
10412 
10413 #ifdef __cplusplus
10414 }  /* End of the 'extern "C"' block */
10415 #endif
10416 #endif /* SQLITE3_H */
10417 
10418 /******** Begin file sqlite3rtree.h *********/
10419 /*
10420 ** 2010 August 30
10421 **
10422 ** The author disclaims copyright to this source code.  In place of
10423 ** a legal notice, here is a blessing:
10424 **
10425 **    May you do good and not evil.
10426 **    May you find forgiveness for yourself and forgive others.
10427 **    May you share freely, never taking more than you give.
10428 **
10429 *************************************************************************
10430 */
10431 
10432 #ifndef _SQLITE3RTREE_H_
10433 #define _SQLITE3RTREE_H_
10434 
10435 
10436 #ifdef __cplusplus
10437 extern "C" {
10438 #endif
10439 
10440 typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry;
10441 typedef struct sqlite3_rtree_query_info sqlite3_rtree_query_info;
10442 
10443 /* The double-precision datatype used by RTree depends on the
10444 ** SQLITE_RTREE_INT_ONLY compile-time option.
10445 */
10446 #ifdef SQLITE_RTREE_INT_ONLY
10447   typedef sqlite3_int64 sqlite3_rtree_dbl;
10448 #else
10449   typedef double sqlite3_rtree_dbl;
10450 #endif
10451 
10452 /*
10453 ** Register a geometry callback named zGeom that can be used as part of an
10454 ** R-Tree geometry query as follows:
10455 **
10456 **   SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...)
10457 */
10458 SQLITE_API int sqlite3_rtree_geometry_callback(
10459   sqlite3 *db,
10460   const char *zGeom,
10461   int (*xGeom)(sqlite3_rtree_geometry*, int, sqlite3_rtree_dbl*,int*),
10462   void *pContext
10463 );
10464 
10465 
10466 /*
10467 ** A pointer to a structure of the following type is passed as the first
10468 ** argument to callbacks registered using rtree_geometry_callback().
10469 */
10470 struct sqlite3_rtree_geometry {
10471   void *pContext;                 /* Copy of pContext passed to s_r_g_c() */
10472   int nParam;                     /* Size of array aParam[] */
10473   sqlite3_rtree_dbl *aParam;      /* Parameters passed to SQL geom function */
10474   void *pUser;                    /* Callback implementation user data */
10475   void (*xDelUser)(void *);       /* Called by SQLite to clean up pUser */
10476 };
10477 
10478 /*
10479 ** Register a 2nd-generation geometry callback named zScore that can be
10480 ** used as part of an R-Tree geometry query as follows:
10481 **
10482 **   SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zQueryFunc(... params ...)
10483 */
10484 SQLITE_API int sqlite3_rtree_query_callback(
10485   sqlite3 *db,
10486   const char *zQueryFunc,
10487   int (*xQueryFunc)(sqlite3_rtree_query_info*),
10488   void *pContext,
10489   void (*xDestructor)(void*)
10490 );
10491 
10492 
10493 /*
10494 ** A pointer to a structure of the following type is passed as the
10495 ** argument to scored geometry callback registered using
10496 ** sqlite3_rtree_query_callback().
10497 **
10498 ** Note that the first 5 fields of this structure are identical to
10499 ** sqlite3_rtree_geometry.  This structure is a subclass of
10500 ** sqlite3_rtree_geometry.
10501 */
10502 struct sqlite3_rtree_query_info {
10503   void *pContext;                   /* pContext from when function registered */
10504   int nParam;                       /* Number of function parameters */
10505   sqlite3_rtree_dbl *aParam;        /* value of function parameters */
10506   void *pUser;                      /* callback can use this, if desired */
10507   void (*xDelUser)(void*);          /* function to free pUser */
10508   sqlite3_rtree_dbl *aCoord;        /* Coordinates of node or entry to check */
10509   unsigned int *anQueue;            /* Number of pending entries in the queue */
10510   int nCoord;                       /* Number of coordinates */
10511   int iLevel;                       /* Level of current node or entry */
10512   int mxLevel;                      /* The largest iLevel value in the tree */
10513   sqlite3_int64 iRowid;             /* Rowid for current entry */
10514   sqlite3_rtree_dbl rParentScore;   /* Score of parent node */
10515   int eParentWithin;                /* Visibility of parent node */
10516   int eWithin;                      /* OUT: Visibility */
10517   sqlite3_rtree_dbl rScore;         /* OUT: Write the score here */
10518   /* The following fields are only available in 3.8.11 and later */
10519   sqlite3_value **apSqlParam;       /* Original SQL values of parameters */
10520 };
10521 
10522 /*
10523 ** Allowed values for sqlite3_rtree_query.eWithin and .eParentWithin.
10524 */
10525 #define NOT_WITHIN       0   /* Object completely outside of query region */
10526 #define PARTLY_WITHIN    1   /* Object partially overlaps query region */
10527 #define FULLY_WITHIN     2   /* Object fully contained within query region */
10528 
10529 
10530 #ifdef __cplusplus
10531 }  /* end of the 'extern "C"' block */
10532 #endif
10533 
10534 #endif  /* ifndef _SQLITE3RTREE_H_ */
10535 
10536 /******** End of sqlite3rtree.h *********/
10537 /******** Begin file sqlite3session.h *********/
10538 
10539 #if !defined(__SQLITESESSION_H_) && defined(SQLITE_ENABLE_SESSION)
10540 #define __SQLITESESSION_H_ 1
10541 
10542 /*
10543 ** Make sure we can call this stuff from C++.
10544 */
10545 #ifdef __cplusplus
10546 extern "C" {
10547 #endif
10548 
10549 
10550 /*
10551 ** CAPI3REF: Session Object Handle
10552 **
10553 ** An instance of this object is a [session] that can be used to
10554 ** record changes to a database.
10555 */
10556 typedef struct sqlite3_session sqlite3_session;
10557 
10558 /*
10559 ** CAPI3REF: Changeset Iterator Handle
10560 **
10561 ** An instance of this object acts as a cursor for iterating
10562 ** over the elements of a [changeset] or [patchset].
10563 */
10564 typedef struct sqlite3_changeset_iter sqlite3_changeset_iter;
10565 
10566 /*
10567 ** CAPI3REF: Create A New Session Object
10568 ** CONSTRUCTOR: sqlite3_session
10569 **
10570 ** Create a new session object attached to database handle db. If successful,
10571 ** a pointer to the new object is written to *ppSession and SQLITE_OK is
10572 ** returned. If an error occurs, *ppSession is set to NULL and an SQLite
10573 ** error code (e.g. SQLITE_NOMEM) is returned.
10574 **
10575 ** It is possible to create multiple session objects attached to a single
10576 ** database handle.
10577 **
10578 ** Session objects created using this function should be deleted using the
10579 ** [sqlite3session_delete()] function before the database handle that they
10580 ** are attached to is itself closed. If the database handle is closed before
10581 ** the session object is deleted, then the results of calling any session
10582 ** module function, including [sqlite3session_delete()] on the session object
10583 ** are undefined.
10584 **
10585 ** Because the session module uses the [sqlite3_preupdate_hook()] API, it
10586 ** is not possible for an application to register a pre-update hook on a
10587 ** database handle that has one or more session objects attached. Nor is
10588 ** it possible to create a session object attached to a database handle for
10589 ** which a pre-update hook is already defined. The results of attempting
10590 ** either of these things are undefined.
10591 **
10592 ** The session object will be used to create changesets for tables in
10593 ** database zDb, where zDb is either "main", or "temp", or the name of an
10594 ** attached database. It is not an error if database zDb is not attached
10595 ** to the database when the session object is created.
10596 */
10597 SQLITE_API int sqlite3session_create(
10598   sqlite3 *db,                    /* Database handle */
10599   const char *zDb,                /* Name of db (e.g. "main") */
10600   sqlite3_session **ppSession     /* OUT: New session object */
10601 );
10602 
10603 /*
10604 ** CAPI3REF: Delete A Session Object
10605 ** DESTRUCTOR: sqlite3_session
10606 **
10607 ** Delete a session object previously allocated using
10608 ** [sqlite3session_create()]. Once a session object has been deleted, the
10609 ** results of attempting to use pSession with any other session module
10610 ** function are undefined.
10611 **
10612 ** Session objects must be deleted before the database handle to which they
10613 ** are attached is closed. Refer to the documentation for
10614 ** [sqlite3session_create()] for details.
10615 */
10616 SQLITE_API void sqlite3session_delete(sqlite3_session *pSession);
10617 
10618 /*
10619 ** CAPIREF: Conigure a Session Object
10620 ** METHOD: sqlite3_session
10621 **
10622 ** This method is used to configure a session object after it has been
10623 ** created. At present the only valid value for the second parameter is
10624 ** [SQLITE_SESSION_OBJCONFIG_SIZE].
10625 **
10626 ** Arguments for sqlite3session_object_config()
10627 **
10628 ** The following values may passed as the the 4th parameter to
10629 ** sqlite3session_object_config().
10630 **
10631 ** <dt>SQLITE_SESSION_OBJCONFIG_SIZE <dd>
10632 **   This option is used to set, clear or query the flag that enables
10633 **   the [sqlite3session_changeset_size()] API. Because it imposes some
10634 **   computational overhead, this API is disabled by default. Argument
10635 **   pArg must point to a value of type (int). If the value is initially
10636 **   0, then the sqlite3session_changeset_size() API is disabled. If it
10637 **   is greater than 0, then the same API is enabled. Or, if the initial
10638 **   value is less than zero, no change is made. In all cases the (int)
10639 **   variable is set to 1 if the sqlite3session_changeset_size() API is
10640 **   enabled following the current call, or 0 otherwise.
10641 **
10642 **   It is an error (SQLITE_MISUSE) to attempt to modify this setting after
10643 **   the first table has been attached to the session object.
10644 */
10645 SQLITE_API int sqlite3session_object_config(sqlite3_session*, int op, void *pArg);
10646 
10647 /*
10648 */
10649 #define SQLITE_SESSION_OBJCONFIG_SIZE 1
10650 
10651 /*
10652 ** CAPI3REF: Enable Or Disable A Session Object
10653 ** METHOD: sqlite3_session
10654 **
10655 ** Enable or disable the recording of changes by a session object. When
10656 ** enabled, a session object records changes made to the database. When
10657 ** disabled - it does not. A newly created session object is enabled.
10658 ** Refer to the documentation for [sqlite3session_changeset()] for further
10659 ** details regarding how enabling and disabling a session object affects
10660 ** the eventual changesets.
10661 **
10662 ** Passing zero to this function disables the session. Passing a value
10663 ** greater than zero enables it. Passing a value less than zero is a
10664 ** no-op, and may be used to query the current state of the session.
10665 **
10666 ** The return value indicates the final state of the session object: 0 if
10667 ** the session is disabled, or 1 if it is enabled.
10668 */
10669 SQLITE_API int sqlite3session_enable(sqlite3_session *pSession, int bEnable);
10670 
10671 /*
10672 ** CAPI3REF: Set Or Clear the Indirect Change Flag
10673 ** METHOD: sqlite3_session
10674 **
10675 ** Each change recorded by a session object is marked as either direct or
10676 ** indirect. A change is marked as indirect if either:
10677 **
10678 ** <ul>
10679 **   <li> The session object "indirect" flag is set when the change is
10680 **        made, or
10681 **   <li> The change is made by an SQL trigger or foreign key action
10682 **        instead of directly as a result of a users SQL statement.
10683 ** </ul>
10684 **
10685 ** If a single row is affected by more than one operation within a session,
10686 ** then the change is considered indirect if all operations meet the criteria
10687 ** for an indirect change above, or direct otherwise.
10688 **
10689 ** This function is used to set, clear or query the session object indirect
10690 ** flag.  If the second argument passed to this function is zero, then the
10691 ** indirect flag is cleared. If it is greater than zero, the indirect flag
10692 ** is set. Passing a value less than zero does not modify the current value
10693 ** of the indirect flag, and may be used to query the current state of the
10694 ** indirect flag for the specified session object.
10695 **
10696 ** The return value indicates the final state of the indirect flag: 0 if
10697 ** it is clear, or 1 if it is set.
10698 */
10699 SQLITE_API int sqlite3session_indirect(sqlite3_session *pSession, int bIndirect);
10700 
10701 /*
10702 ** CAPI3REF: Attach A Table To A Session Object
10703 ** METHOD: sqlite3_session
10704 **
10705 ** If argument zTab is not NULL, then it is the name of a table to attach
10706 ** to the session object passed as the first argument. All subsequent changes
10707 ** made to the table while the session object is enabled will be recorded. See
10708 ** documentation for [sqlite3session_changeset()] for further details.
10709 **
10710 ** Or, if argument zTab is NULL, then changes are recorded for all tables
10711 ** in the database. If additional tables are added to the database (by
10712 ** executing "CREATE TABLE" statements) after this call is made, changes for
10713 ** the new tables are also recorded.
10714 **
10715 ** Changes can only be recorded for tables that have a PRIMARY KEY explicitly
10716 ** defined as part of their CREATE TABLE statement. It does not matter if the
10717 ** PRIMARY KEY is an "INTEGER PRIMARY KEY" (rowid alias) or not. The PRIMARY
10718 ** KEY may consist of a single column, or may be a composite key.
10719 **
10720 ** It is not an error if the named table does not exist in the database. Nor
10721 ** is it an error if the named table does not have a PRIMARY KEY. However,
10722 ** no changes will be recorded in either of these scenarios.
10723 **
10724 ** Changes are not recorded for individual rows that have NULL values stored
10725 ** in one or more of their PRIMARY KEY columns.
10726 **
10727 ** SQLITE_OK is returned if the call completes without error. Or, if an error
10728 ** occurs, an SQLite error code (e.g. SQLITE_NOMEM) is returned.
10729 **
10730 ** <h3>Special sqlite_stat1 Handling</h3>
10731 **
10732 ** As of SQLite version 3.22.0, the "sqlite_stat1" table is an exception to
10733 ** some of the rules above. In SQLite, the schema of sqlite_stat1 is:
10734 **  <pre>
10735 **  &nbsp;     CREATE TABLE sqlite_stat1(tbl,idx,stat)
10736 **  </pre>
10737 **
10738 ** Even though sqlite_stat1 does not have a PRIMARY KEY, changes are
10739 ** recorded for it as if the PRIMARY KEY is (tbl,idx). Additionally, changes
10740 ** are recorded for rows for which (idx IS NULL) is true. However, for such
10741 ** rows a zero-length blob (SQL value X'') is stored in the changeset or
10742 ** patchset instead of a NULL value. This allows such changesets to be
10743 ** manipulated by legacy implementations of sqlite3changeset_invert(),
10744 ** concat() and similar.
10745 **
10746 ** The sqlite3changeset_apply() function automatically converts the
10747 ** zero-length blob back to a NULL value when updating the sqlite_stat1
10748 ** table. However, if the application calls sqlite3changeset_new(),
10749 ** sqlite3changeset_old() or sqlite3changeset_conflict on a changeset
10750 ** iterator directly (including on a changeset iterator passed to a
10751 ** conflict-handler callback) then the X'' value is returned. The application
10752 ** must translate X'' to NULL itself if required.
10753 **
10754 ** Legacy (older than 3.22.0) versions of the sessions module cannot capture
10755 ** changes made to the sqlite_stat1 table. Legacy versions of the
10756 ** sqlite3changeset_apply() function silently ignore any modifications to the
10757 ** sqlite_stat1 table that are part of a changeset or patchset.
10758 */
10759 SQLITE_API int sqlite3session_attach(
10760   sqlite3_session *pSession,      /* Session object */
10761   const char *zTab                /* Table name */
10762 );
10763 
10764 /*
10765 ** CAPI3REF: Set a table filter on a Session Object.
10766 ** METHOD: sqlite3_session
10767 **
10768 ** The second argument (xFilter) is the "filter callback". For changes to rows
10769 ** in tables that are not attached to the Session object, the filter is called
10770 ** to determine whether changes to the table's rows should be tracked or not.
10771 ** If xFilter returns 0, changes are not tracked. Note that once a table is
10772 ** attached, xFilter will not be called again.
10773 */
10774 SQLITE_API void sqlite3session_table_filter(
10775   sqlite3_session *pSession,      /* Session object */
10776   int(*xFilter)(
10777     void *pCtx,                   /* Copy of third arg to _filter_table() */
10778     const char *zTab              /* Table name */
10779   ),
10780   void *pCtx                      /* First argument passed to xFilter */
10781 );
10782 
10783 /*
10784 ** CAPI3REF: Generate A Changeset From A Session Object
10785 ** METHOD: sqlite3_session
10786 **
10787 ** Obtain a changeset containing changes to the tables attached to the
10788 ** session object passed as the first argument. If successful,
10789 ** set *ppChangeset to point to a buffer containing the changeset
10790 ** and *pnChangeset to the size of the changeset in bytes before returning
10791 ** SQLITE_OK. If an error occurs, set both *ppChangeset and *pnChangeset to
10792 ** zero and return an SQLite error code.
10793 **
10794 ** A changeset consists of zero or more INSERT, UPDATE and/or DELETE changes,
10795 ** each representing a change to a single row of an attached table. An INSERT
10796 ** change contains the values of each field of a new database row. A DELETE
10797 ** contains the original values of each field of a deleted database row. An
10798 ** UPDATE change contains the original values of each field of an updated
10799 ** database row along with the updated values for each updated non-primary-key
10800 ** column. It is not possible for an UPDATE change to represent a change that
10801 ** modifies the values of primary key columns. If such a change is made, it
10802 ** is represented in a changeset as a DELETE followed by an INSERT.
10803 **
10804 ** Changes are not recorded for rows that have NULL values stored in one or
10805 ** more of their PRIMARY KEY columns. If such a row is inserted or deleted,
10806 ** no corresponding change is present in the changesets returned by this
10807 ** function. If an existing row with one or more NULL values stored in
10808 ** PRIMARY KEY columns is updated so that all PRIMARY KEY columns are non-NULL,
10809 ** only an INSERT is appears in the changeset. Similarly, if an existing row
10810 ** with non-NULL PRIMARY KEY values is updated so that one or more of its
10811 ** PRIMARY KEY columns are set to NULL, the resulting changeset contains a
10812 ** DELETE change only.
10813 **
10814 ** The contents of a changeset may be traversed using an iterator created
10815 ** using the [sqlite3changeset_start()] API. A changeset may be applied to
10816 ** a database with a compatible schema using the [sqlite3changeset_apply()]
10817 ** API.
10818 **
10819 ** Within a changeset generated by this function, all changes related to a
10820 ** single table are grouped together. In other words, when iterating through
10821 ** a changeset or when applying a changeset to a database, all changes related
10822 ** to a single table are processed before moving on to the next table. Tables
10823 ** are sorted in the same order in which they were attached (or auto-attached)
10824 ** to the sqlite3_session object. The order in which the changes related to
10825 ** a single table are stored is undefined.
10826 **
10827 ** Following a successful call to this function, it is the responsibility of
10828 ** the caller to eventually free the buffer that *ppChangeset points to using
10829 ** [sqlite3_free()].
10830 **
10831 ** <h3>Changeset Generation</h3>
10832 **
10833 ** Once a table has been attached to a session object, the session object
10834 ** records the primary key values of all new rows inserted into the table.
10835 ** It also records the original primary key and other column values of any
10836 ** deleted or updated rows. For each unique primary key value, data is only
10837 ** recorded once - the first time a row with said primary key is inserted,
10838 ** updated or deleted in the lifetime of the session.
10839 **
10840 ** There is one exception to the previous paragraph: when a row is inserted,
10841 ** updated or deleted, if one or more of its primary key columns contain a
10842 ** NULL value, no record of the change is made.
10843 **
10844 ** The session object therefore accumulates two types of records - those
10845 ** that consist of primary key values only (created when the user inserts
10846 ** a new record) and those that consist of the primary key values and the
10847 ** original values of other table columns (created when the users deletes
10848 ** or updates a record).
10849 **
10850 ** When this function is called, the requested changeset is created using
10851 ** both the accumulated records and the current contents of the database
10852 ** file. Specifically:
10853 **
10854 ** <ul>
10855 **   <li> For each record generated by an insert, the database is queried
10856 **        for a row with a matching primary key. If one is found, an INSERT
10857 **        change is added to the changeset. If no such row is found, no change
10858 **        is added to the changeset.
10859 **
10860 **   <li> For each record generated by an update or delete, the database is
10861 **        queried for a row with a matching primary key. If such a row is
10862 **        found and one or more of the non-primary key fields have been
10863 **        modified from their original values, an UPDATE change is added to
10864 **        the changeset. Or, if no such row is found in the table, a DELETE
10865 **        change is added to the changeset. If there is a row with a matching
10866 **        primary key in the database, but all fields contain their original
10867 **        values, no change is added to the changeset.
10868 ** </ul>
10869 **
10870 ** This means, amongst other things, that if a row is inserted and then later
10871 ** deleted while a session object is active, neither the insert nor the delete
10872 ** will be present in the changeset. Or if a row is deleted and then later a
10873 ** row with the same primary key values inserted while a session object is
10874 ** active, the resulting changeset will contain an UPDATE change instead of
10875 ** a DELETE and an INSERT.
10876 **
10877 ** When a session object is disabled (see the [sqlite3session_enable()] API),
10878 ** it does not accumulate records when rows are inserted, updated or deleted.
10879 ** This may appear to have some counter-intuitive effects if a single row
10880 ** is written to more than once during a session. For example, if a row
10881 ** is inserted while a session object is enabled, then later deleted while
10882 ** the same session object is disabled, no INSERT record will appear in the
10883 ** changeset, even though the delete took place while the session was disabled.
10884 ** Or, if one field of a row is updated while a session is disabled, and
10885 ** another field of the same row is updated while the session is enabled, the
10886 ** resulting changeset will contain an UPDATE change that updates both fields.
10887 */
10888 SQLITE_API int sqlite3session_changeset(
10889   sqlite3_session *pSession,      /* Session object */
10890   int *pnChangeset,               /* OUT: Size of buffer at *ppChangeset */
10891   void **ppChangeset              /* OUT: Buffer containing changeset */
10892 );
10893 
10894 /*
10895 ** CAPI3REF: Return An Upper-limit For The Size Of The Changeset
10896 ** METHOD: sqlite3_session
10897 **
10898 ** By default, this function always returns 0. For it to return
10899 ** a useful result, the sqlite3_session object must have been configured
10900 ** to enable this API using sqlite3session_object_config() with the
10901 ** SQLITE_SESSION_OBJCONFIG_SIZE verb.
10902 **
10903 ** When enabled, this function returns an upper limit, in bytes, for the size
10904 ** of the changeset that might be produced if sqlite3session_changeset() were
10905 ** called. The final changeset size might be equal to or smaller than the
10906 ** size in bytes returned by this function.
10907 */
10908 SQLITE_API sqlite3_int64 sqlite3session_changeset_size(sqlite3_session *pSession);
10909 
10910 /*
10911 ** CAPI3REF: Load The Difference Between Tables Into A Session
10912 ** METHOD: sqlite3_session
10913 **
10914 ** If it is not already attached to the session object passed as the first
10915 ** argument, this function attaches table zTbl in the same manner as the
10916 ** [sqlite3session_attach()] function. If zTbl does not exist, or if it
10917 ** does not have a primary key, this function is a no-op (but does not return
10918 ** an error).
10919 **
10920 ** Argument zFromDb must be the name of a database ("main", "temp" etc.)
10921 ** attached to the same database handle as the session object that contains
10922 ** a table compatible with the table attached to the session by this function.
10923 ** A table is considered compatible if it:
10924 **
10925 ** <ul>
10926 **   <li> Has the same name,
10927 **   <li> Has the same set of columns declared in the same order, and
10928 **   <li> Has the same PRIMARY KEY definition.
10929 ** </ul>
10930 **
10931 ** If the tables are not compatible, SQLITE_SCHEMA is returned. If the tables
10932 ** are compatible but do not have any PRIMARY KEY columns, it is not an error
10933 ** but no changes are added to the session object. As with other session
10934 ** APIs, tables without PRIMARY KEYs are simply ignored.
10935 **
10936 ** This function adds a set of changes to the session object that could be
10937 ** used to update the table in database zFrom (call this the "from-table")
10938 ** so that its content is the same as the table attached to the session
10939 ** object (call this the "to-table"). Specifically:
10940 **
10941 ** <ul>
10942 **   <li> For each row (primary key) that exists in the to-table but not in
10943 **     the from-table, an INSERT record is added to the session object.
10944 **
10945 **   <li> For each row (primary key) that exists in the to-table but not in
10946 **     the from-table, a DELETE record is added to the session object.
10947 **
10948 **   <li> For each row (primary key) that exists in both tables, but features
10949 **     different non-PK values in each, an UPDATE record is added to the
10950 **     session.
10951 ** </ul>
10952 **
10953 ** To clarify, if this function is called and then a changeset constructed
10954 ** using [sqlite3session_changeset()], then after applying that changeset to
10955 ** database zFrom the contents of the two compatible tables would be
10956 ** identical.
10957 **
10958 ** It an error if database zFrom does not exist or does not contain the
10959 ** required compatible table.
10960 **
10961 ** If the operation is successful, SQLITE_OK is returned. Otherwise, an SQLite
10962 ** error code. In this case, if argument pzErrMsg is not NULL, *pzErrMsg
10963 ** may be set to point to a buffer containing an English language error
10964 ** message. It is the responsibility of the caller to free this buffer using
10965 ** sqlite3_free().
10966 */
10967 SQLITE_API int sqlite3session_diff(
10968   sqlite3_session *pSession,
10969   const char *zFromDb,
10970   const char *zTbl,
10971   char **pzErrMsg
10972 );
10973 
10974 
10975 /*
10976 ** CAPI3REF: Generate A Patchset From A Session Object
10977 ** METHOD: sqlite3_session
10978 **
10979 ** The differences between a patchset and a changeset are that:
10980 **
10981 ** <ul>
10982 **   <li> DELETE records consist of the primary key fields only. The
10983 **        original values of other fields are omitted.
10984 **   <li> The original values of any modified fields are omitted from
10985 **        UPDATE records.
10986 ** </ul>
10987 **
10988 ** A patchset blob may be used with up to date versions of all
10989 ** sqlite3changeset_xxx API functions except for sqlite3changeset_invert(),
10990 ** which returns SQLITE_CORRUPT if it is passed a patchset. Similarly,
10991 ** attempting to use a patchset blob with old versions of the
10992 ** sqlite3changeset_xxx APIs also provokes an SQLITE_CORRUPT error.
10993 **
10994 ** Because the non-primary key "old.*" fields are omitted, no
10995 ** SQLITE_CHANGESET_DATA conflicts can be detected or reported if a patchset
10996 ** is passed to the sqlite3changeset_apply() API. Other conflict types work
10997 ** in the same way as for changesets.
10998 **
10999 ** Changes within a patchset are ordered in the same way as for changesets
11000 ** generated by the sqlite3session_changeset() function (i.e. all changes for
11001 ** a single table are grouped together, tables appear in the order in which
11002 ** they were attached to the session object).
11003 */
11004 SQLITE_API int sqlite3session_patchset(
11005   sqlite3_session *pSession,      /* Session object */
11006   int *pnPatchset,                /* OUT: Size of buffer at *ppPatchset */
11007   void **ppPatchset               /* OUT: Buffer containing patchset */
11008 );
11009 
11010 /*
11011 ** CAPI3REF: Test if a changeset has recorded any changes.
11012 **
11013 ** Return non-zero if no changes to attached tables have been recorded by
11014 ** the session object passed as the first argument. Otherwise, if one or
11015 ** more changes have been recorded, return zero.
11016 **
11017 ** Even if this function returns zero, it is possible that calling
11018 ** [sqlite3session_changeset()] on the session handle may still return a
11019 ** changeset that contains no changes. This can happen when a row in
11020 ** an attached table is modified and then later on the original values
11021 ** are restored. However, if this function returns non-zero, then it is
11022 ** guaranteed that a call to sqlite3session_changeset() will return a
11023 ** changeset containing zero changes.
11024 */
11025 SQLITE_API int sqlite3session_isempty(sqlite3_session *pSession);
11026 
11027 /*
11028 ** CAPI3REF: Query for the amount of heap memory used by a session object.
11029 **
11030 ** This API returns the total amount of heap memory in bytes currently
11031 ** used by the session object passed as the only argument.
11032 */
11033 SQLITE_API sqlite3_int64 sqlite3session_memory_used(sqlite3_session *pSession);
11034 
11035 /*
11036 ** CAPI3REF: Create An Iterator To Traverse A Changeset
11037 ** CONSTRUCTOR: sqlite3_changeset_iter
11038 **
11039 ** Create an iterator used to iterate through the contents of a changeset.
11040 ** If successful, *pp is set to point to the iterator handle and SQLITE_OK
11041 ** is returned. Otherwise, if an error occurs, *pp is set to zero and an
11042 ** SQLite error code is returned.
11043 **
11044 ** The following functions can be used to advance and query a changeset
11045 ** iterator created by this function:
11046 **
11047 ** <ul>
11048 **   <li> [sqlite3changeset_next()]
11049 **   <li> [sqlite3changeset_op()]
11050 **   <li> [sqlite3changeset_new()]
11051 **   <li> [sqlite3changeset_old()]
11052 ** </ul>
11053 **
11054 ** It is the responsibility of the caller to eventually destroy the iterator
11055 ** by passing it to [sqlite3changeset_finalize()]. The buffer containing the
11056 ** changeset (pChangeset) must remain valid until after the iterator is
11057 ** destroyed.
11058 **
11059 ** Assuming the changeset blob was created by one of the
11060 ** [sqlite3session_changeset()], [sqlite3changeset_concat()] or
11061 ** [sqlite3changeset_invert()] functions, all changes within the changeset
11062 ** that apply to a single table are grouped together. This means that when
11063 ** an application iterates through a changeset using an iterator created by
11064 ** this function, all changes that relate to a single table are visited
11065 ** consecutively. There is no chance that the iterator will visit a change
11066 ** the applies to table X, then one for table Y, and then later on visit
11067 ** another change for table X.
11068 **
11069 ** The behavior of sqlite3changeset_start_v2() and its streaming equivalent
11070 ** may be modified by passing a combination of
11071 ** [SQLITE_CHANGESETSTART_INVERT | supported flags] as the 4th parameter.
11072 **
11073 ** Note that the sqlite3changeset_start_v2() API is still <b>experimental</b>
11074 ** and therefore subject to change.
11075 */
11076 SQLITE_API int sqlite3changeset_start(
11077   sqlite3_changeset_iter **pp,    /* OUT: New changeset iterator handle */
11078   int nChangeset,                 /* Size of changeset blob in bytes */
11079   void *pChangeset                /* Pointer to blob containing changeset */
11080 );
11081 SQLITE_API int sqlite3changeset_start_v2(
11082   sqlite3_changeset_iter **pp,    /* OUT: New changeset iterator handle */
11083   int nChangeset,                 /* Size of changeset blob in bytes */
11084   void *pChangeset,               /* Pointer to blob containing changeset */
11085   int flags                       /* SESSION_CHANGESETSTART_* flags */
11086 );
11087 
11088 /*
11089 ** CAPI3REF: Flags for sqlite3changeset_start_v2
11090 **
11091 ** The following flags may passed via the 4th parameter to
11092 ** [sqlite3changeset_start_v2] and [sqlite3changeset_start_v2_strm]:
11093 **
11094 ** <dt>SQLITE_CHANGESETAPPLY_INVERT <dd>
11095 **   Invert the changeset while iterating through it. This is equivalent to
11096 **   inverting a changeset using sqlite3changeset_invert() before applying it.
11097 **   It is an error to specify this flag with a patchset.
11098 */
11099 #define SQLITE_CHANGESETSTART_INVERT        0x0002
11100 
11101 
11102 /*
11103 ** CAPI3REF: Advance A Changeset Iterator
11104 ** METHOD: sqlite3_changeset_iter
11105 **
11106 ** This function may only be used with iterators created by the function
11107 ** [sqlite3changeset_start()]. If it is called on an iterator passed to
11108 ** a conflict-handler callback by [sqlite3changeset_apply()], SQLITE_MISUSE
11109 ** is returned and the call has no effect.
11110 **
11111 ** Immediately after an iterator is created by sqlite3changeset_start(), it
11112 ** does not point to any change in the changeset. Assuming the changeset
11113 ** is not empty, the first call to this function advances the iterator to
11114 ** point to the first change in the changeset. Each subsequent call advances
11115 ** the iterator to point to the next change in the changeset (if any). If
11116 ** no error occurs and the iterator points to a valid change after a call
11117 ** to sqlite3changeset_next() has advanced it, SQLITE_ROW is returned.
11118 ** Otherwise, if all changes in the changeset have already been visited,
11119 ** SQLITE_DONE is returned.
11120 **
11121 ** If an error occurs, an SQLite error code is returned. Possible error
11122 ** codes include SQLITE_CORRUPT (if the changeset buffer is corrupt) or
11123 ** SQLITE_NOMEM.
11124 */
11125 SQLITE_API int sqlite3changeset_next(sqlite3_changeset_iter *pIter);
11126 
11127 /*
11128 ** CAPI3REF: Obtain The Current Operation From A Changeset Iterator
11129 ** METHOD: sqlite3_changeset_iter
11130 **
11131 ** The pIter argument passed to this function may either be an iterator
11132 ** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
11133 ** created by [sqlite3changeset_start()]. In the latter case, the most recent
11134 ** call to [sqlite3changeset_next()] must have returned [SQLITE_ROW]. If this
11135 ** is not the case, this function returns [SQLITE_MISUSE].
11136 **
11137 ** Arguments pOp, pnCol and pzTab may not be NULL. Upon return, three
11138 ** outputs are set through these pointers:
11139 **
11140 ** *pOp is set to one of [SQLITE_INSERT], [SQLITE_DELETE] or [SQLITE_UPDATE],
11141 ** depending on the type of change that the iterator currently points to;
11142 **
11143 ** *pnCol is set to the number of columns in the table affected by the change; and
11144 **
11145 ** *pzTab is set to point to a nul-terminated utf-8 encoded string containing
11146 ** the name of the table affected by the current change. The buffer remains
11147 ** valid until either sqlite3changeset_next() is called on the iterator
11148 ** or until the conflict-handler function returns.
11149 **
11150 ** If pbIndirect is not NULL, then *pbIndirect is set to true (1) if the change
11151 ** is an indirect change, or false (0) otherwise. See the documentation for
11152 ** [sqlite3session_indirect()] for a description of direct and indirect
11153 ** changes.
11154 **
11155 ** If no error occurs, SQLITE_OK is returned. If an error does occur, an
11156 ** SQLite error code is returned. The values of the output variables may not
11157 ** be trusted in this case.
11158 */
11159 SQLITE_API int sqlite3changeset_op(
11160   sqlite3_changeset_iter *pIter,  /* Iterator object */
11161   const char **pzTab,             /* OUT: Pointer to table name */
11162   int *pnCol,                     /* OUT: Number of columns in table */
11163   int *pOp,                       /* OUT: SQLITE_INSERT, DELETE or UPDATE */
11164   int *pbIndirect                 /* OUT: True for an 'indirect' change */
11165 );
11166 
11167 /*
11168 ** CAPI3REF: Obtain The Primary Key Definition Of A Table
11169 ** METHOD: sqlite3_changeset_iter
11170 **
11171 ** For each modified table, a changeset includes the following:
11172 **
11173 ** <ul>
11174 **   <li> The number of columns in the table, and
11175 **   <li> Which of those columns make up the tables PRIMARY KEY.
11176 ** </ul>
11177 **
11178 ** This function is used to find which columns comprise the PRIMARY KEY of
11179 ** the table modified by the change that iterator pIter currently points to.
11180 ** If successful, *pabPK is set to point to an array of nCol entries, where
11181 ** nCol is the number of columns in the table. Elements of *pabPK are set to
11182 ** 0x01 if the corresponding column is part of the tables primary key, or
11183 ** 0x00 if it is not.
11184 **
11185 ** If argument pnCol is not NULL, then *pnCol is set to the number of columns
11186 ** in the table.
11187 **
11188 ** If this function is called when the iterator does not point to a valid
11189 ** entry, SQLITE_MISUSE is returned and the output variables zeroed. Otherwise,
11190 ** SQLITE_OK is returned and the output variables populated as described
11191 ** above.
11192 */
11193 SQLITE_API int sqlite3changeset_pk(
11194   sqlite3_changeset_iter *pIter,  /* Iterator object */
11195   unsigned char **pabPK,          /* OUT: Array of boolean - true for PK cols */
11196   int *pnCol                      /* OUT: Number of entries in output array */
11197 );
11198 
11199 /*
11200 ** CAPI3REF: Obtain old.* Values From A Changeset Iterator
11201 ** METHOD: sqlite3_changeset_iter
11202 **
11203 ** The pIter argument passed to this function may either be an iterator
11204 ** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
11205 ** created by [sqlite3changeset_start()]. In the latter case, the most recent
11206 ** call to [sqlite3changeset_next()] must have returned SQLITE_ROW.
11207 ** Furthermore, it may only be called if the type of change that the iterator
11208 ** currently points to is either [SQLITE_DELETE] or [SQLITE_UPDATE]. Otherwise,
11209 ** this function returns [SQLITE_MISUSE] and sets *ppValue to NULL.
11210 **
11211 ** Argument iVal must be greater than or equal to 0, and less than the number
11212 ** of columns in the table affected by the current change. Otherwise,
11213 ** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
11214 **
11215 ** If successful, this function sets *ppValue to point to a protected
11216 ** sqlite3_value object containing the iVal'th value from the vector of
11217 ** original row values stored as part of the UPDATE or DELETE change and
11218 ** returns SQLITE_OK. The name of the function comes from the fact that this
11219 ** is similar to the "old.*" columns available to update or delete triggers.
11220 **
11221 ** If some other error occurs (e.g. an OOM condition), an SQLite error code
11222 ** is returned and *ppValue is set to NULL.
11223 */
11224 SQLITE_API int sqlite3changeset_old(
11225   sqlite3_changeset_iter *pIter,  /* Changeset iterator */
11226   int iVal,                       /* Column number */
11227   sqlite3_value **ppValue         /* OUT: Old value (or NULL pointer) */
11228 );
11229 
11230 /*
11231 ** CAPI3REF: Obtain new.* Values From A Changeset Iterator
11232 ** METHOD: sqlite3_changeset_iter
11233 **
11234 ** The pIter argument passed to this function may either be an iterator
11235 ** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
11236 ** created by [sqlite3changeset_start()]. In the latter case, the most recent
11237 ** call to [sqlite3changeset_next()] must have returned SQLITE_ROW.
11238 ** Furthermore, it may only be called if the type of change that the iterator
11239 ** currently points to is either [SQLITE_UPDATE] or [SQLITE_INSERT]. Otherwise,
11240 ** this function returns [SQLITE_MISUSE] and sets *ppValue to NULL.
11241 **
11242 ** Argument iVal must be greater than or equal to 0, and less than the number
11243 ** of columns in the table affected by the current change. Otherwise,
11244 ** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
11245 **
11246 ** If successful, this function sets *ppValue to point to a protected
11247 ** sqlite3_value object containing the iVal'th value from the vector of
11248 ** new row values stored as part of the UPDATE or INSERT change and
11249 ** returns SQLITE_OK. If the change is an UPDATE and does not include
11250 ** a new value for the requested column, *ppValue is set to NULL and
11251 ** SQLITE_OK returned. The name of the function comes from the fact that
11252 ** this is similar to the "new.*" columns available to update or delete
11253 ** triggers.
11254 **
11255 ** If some other error occurs (e.g. an OOM condition), an SQLite error code
11256 ** is returned and *ppValue is set to NULL.
11257 */
11258 SQLITE_API int sqlite3changeset_new(
11259   sqlite3_changeset_iter *pIter,  /* Changeset iterator */
11260   int iVal,                       /* Column number */
11261   sqlite3_value **ppValue         /* OUT: New value (or NULL pointer) */
11262 );
11263 
11264 /*
11265 ** CAPI3REF: Obtain Conflicting Row Values From A Changeset Iterator
11266 ** METHOD: sqlite3_changeset_iter
11267 **
11268 ** This function should only be used with iterator objects passed to a
11269 ** conflict-handler callback by [sqlite3changeset_apply()] with either
11270 ** [SQLITE_CHANGESET_DATA] or [SQLITE_CHANGESET_CONFLICT]. If this function
11271 ** is called on any other iterator, [SQLITE_MISUSE] is returned and *ppValue
11272 ** is set to NULL.
11273 **
11274 ** Argument iVal must be greater than or equal to 0, and less than the number
11275 ** of columns in the table affected by the current change. Otherwise,
11276 ** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
11277 **
11278 ** If successful, this function sets *ppValue to point to a protected
11279 ** sqlite3_value object containing the iVal'th value from the
11280 ** "conflicting row" associated with the current conflict-handler callback
11281 ** and returns SQLITE_OK.
11282 **
11283 ** If some other error occurs (e.g. an OOM condition), an SQLite error code
11284 ** is returned and *ppValue is set to NULL.
11285 */
11286 SQLITE_API int sqlite3changeset_conflict(
11287   sqlite3_changeset_iter *pIter,  /* Changeset iterator */
11288   int iVal,                       /* Column number */
11289   sqlite3_value **ppValue         /* OUT: Value from conflicting row */
11290 );
11291 
11292 /*
11293 ** CAPI3REF: Determine The Number Of Foreign Key Constraint Violations
11294 ** METHOD: sqlite3_changeset_iter
11295 **
11296 ** This function may only be called with an iterator passed to an
11297 ** SQLITE_CHANGESET_FOREIGN_KEY conflict handler callback. In this case
11298 ** it sets the output variable to the total number of known foreign key
11299 ** violations in the destination database and returns SQLITE_OK.
11300 **
11301 ** In all other cases this function returns SQLITE_MISUSE.
11302 */
11303 SQLITE_API int sqlite3changeset_fk_conflicts(
11304   sqlite3_changeset_iter *pIter,  /* Changeset iterator */
11305   int *pnOut                      /* OUT: Number of FK violations */
11306 );
11307 
11308 
11309 /*
11310 ** CAPI3REF: Finalize A Changeset Iterator
11311 ** METHOD: sqlite3_changeset_iter
11312 **
11313 ** This function is used to finalize an iterator allocated with
11314 ** [sqlite3changeset_start()].
11315 **
11316 ** This function should only be called on iterators created using the
11317 ** [sqlite3changeset_start()] function. If an application calls this
11318 ** function with an iterator passed to a conflict-handler by
11319 ** [sqlite3changeset_apply()], [SQLITE_MISUSE] is immediately returned and the
11320 ** call has no effect.
11321 **
11322 ** If an error was encountered within a call to an sqlite3changeset_xxx()
11323 ** function (for example an [SQLITE_CORRUPT] in [sqlite3changeset_next()] or an
11324 ** [SQLITE_NOMEM] in [sqlite3changeset_new()]) then an error code corresponding
11325 ** to that error is returned by this function. Otherwise, SQLITE_OK is
11326 ** returned. This is to allow the following pattern (pseudo-code):
11327 **
11328 ** <pre>
11329 **   sqlite3changeset_start();
11330 **   while( SQLITE_ROW==sqlite3changeset_next() ){
11331 **     // Do something with change.
11332 **   }
11333 **   rc = sqlite3changeset_finalize();
11334 **   if( rc!=SQLITE_OK ){
11335 **     // An error has occurred
11336 **   }
11337 ** </pre>
11338 */
11339 SQLITE_API int sqlite3changeset_finalize(sqlite3_changeset_iter *pIter);
11340 
11341 /*
11342 ** CAPI3REF: Invert A Changeset
11343 **
11344 ** This function is used to "invert" a changeset object. Applying an inverted
11345 ** changeset to a database reverses the effects of applying the uninverted
11346 ** changeset. Specifically:
11347 **
11348 ** <ul>
11349 **   <li> Each DELETE change is changed to an INSERT, and
11350 **   <li> Each INSERT change is changed to a DELETE, and
11351 **   <li> For each UPDATE change, the old.* and new.* values are exchanged.
11352 ** </ul>
11353 **
11354 ** This function does not change the order in which changes appear within
11355 ** the changeset. It merely reverses the sense of each individual change.
11356 **
11357 ** If successful, a pointer to a buffer containing the inverted changeset
11358 ** is stored in *ppOut, the size of the same buffer is stored in *pnOut, and
11359 ** SQLITE_OK is returned. If an error occurs, both *pnOut and *ppOut are
11360 ** zeroed and an SQLite error code returned.
11361 **
11362 ** It is the responsibility of the caller to eventually call sqlite3_free()
11363 ** on the *ppOut pointer to free the buffer allocation following a successful
11364 ** call to this function.
11365 **
11366 ** WARNING/TODO: This function currently assumes that the input is a valid
11367 ** changeset. If it is not, the results are undefined.
11368 */
11369 SQLITE_API int sqlite3changeset_invert(
11370   int nIn, const void *pIn,       /* Input changeset */
11371   int *pnOut, void **ppOut        /* OUT: Inverse of input */
11372 );
11373 
11374 /*
11375 ** CAPI3REF: Concatenate Two Changeset Objects
11376 **
11377 ** This function is used to concatenate two changesets, A and B, into a
11378 ** single changeset. The result is a changeset equivalent to applying
11379 ** changeset A followed by changeset B.
11380 **
11381 ** This function combines the two input changesets using an
11382 ** sqlite3_changegroup object. Calling it produces similar results as the
11383 ** following code fragment:
11384 **
11385 ** <pre>
11386 **   sqlite3_changegroup *pGrp;
11387 **   rc = sqlite3_changegroup_new(&pGrp);
11388 **   if( rc==SQLITE_OK ) rc = sqlite3changegroup_add(pGrp, nA, pA);
11389 **   if( rc==SQLITE_OK ) rc = sqlite3changegroup_add(pGrp, nB, pB);
11390 **   if( rc==SQLITE_OK ){
11391 **     rc = sqlite3changegroup_output(pGrp, pnOut, ppOut);
11392 **   }else{
11393 **     *ppOut = 0;
11394 **     *pnOut = 0;
11395 **   }
11396 ** </pre>
11397 **
11398 ** Refer to the sqlite3_changegroup documentation below for details.
11399 */
11400 SQLITE_API int sqlite3changeset_concat(
11401   int nA,                         /* Number of bytes in buffer pA */
11402   void *pA,                       /* Pointer to buffer containing changeset A */
11403   int nB,                         /* Number of bytes in buffer pB */
11404   void *pB,                       /* Pointer to buffer containing changeset B */
11405   int *pnOut,                     /* OUT: Number of bytes in output changeset */
11406   void **ppOut                    /* OUT: Buffer containing output changeset */
11407 );
11408 
11409 
11410 /*
11411 ** CAPI3REF: Changegroup Handle
11412 **
11413 ** A changegroup is an object used to combine two or more
11414 ** [changesets] or [patchsets]
11415 */
11416 typedef struct sqlite3_changegroup sqlite3_changegroup;
11417 
11418 /*
11419 ** CAPI3REF: Create A New Changegroup Object
11420 ** CONSTRUCTOR: sqlite3_changegroup
11421 **
11422 ** An sqlite3_changegroup object is used to combine two or more changesets
11423 ** (or patchsets) into a single changeset (or patchset). A single changegroup
11424 ** object may combine changesets or patchsets, but not both. The output is
11425 ** always in the same format as the input.
11426 **
11427 ** If successful, this function returns SQLITE_OK and populates (*pp) with
11428 ** a pointer to a new sqlite3_changegroup object before returning. The caller
11429 ** should eventually free the returned object using a call to
11430 ** sqlite3changegroup_delete(). If an error occurs, an SQLite error code
11431 ** (i.e. SQLITE_NOMEM) is returned and *pp is set to NULL.
11432 **
11433 ** The usual usage pattern for an sqlite3_changegroup object is as follows:
11434 **
11435 ** <ul>
11436 **   <li> It is created using a call to sqlite3changegroup_new().
11437 **
11438 **   <li> Zero or more changesets (or patchsets) are added to the object
11439 **        by calling sqlite3changegroup_add().
11440 **
11441 **   <li> The result of combining all input changesets together is obtained
11442 **        by the application via a call to sqlite3changegroup_output().
11443 **
11444 **   <li> The object is deleted using a call to sqlite3changegroup_delete().
11445 ** </ul>
11446 **
11447 ** Any number of calls to add() and output() may be made between the calls to
11448 ** new() and delete(), and in any order.
11449 **
11450 ** As well as the regular sqlite3changegroup_add() and
11451 ** sqlite3changegroup_output() functions, also available are the streaming
11452 ** versions sqlite3changegroup_add_strm() and sqlite3changegroup_output_strm().
11453 */
11454 SQLITE_API int sqlite3changegroup_new(sqlite3_changegroup **pp);
11455 
11456 /*
11457 ** CAPI3REF: Add A Changeset To A Changegroup
11458 ** METHOD: sqlite3_changegroup
11459 **
11460 ** Add all changes within the changeset (or patchset) in buffer pData (size
11461 ** nData bytes) to the changegroup.
11462 **
11463 ** If the buffer contains a patchset, then all prior calls to this function
11464 ** on the same changegroup object must also have specified patchsets. Or, if
11465 ** the buffer contains a changeset, so must have the earlier calls to this
11466 ** function. Otherwise, SQLITE_ERROR is returned and no changes are added
11467 ** to the changegroup.
11468 **
11469 ** Rows within the changeset and changegroup are identified by the values in
11470 ** their PRIMARY KEY columns. A change in the changeset is considered to
11471 ** apply to the same row as a change already present in the changegroup if
11472 ** the two rows have the same primary key.
11473 **
11474 ** Changes to rows that do not already appear in the changegroup are
11475 ** simply copied into it. Or, if both the new changeset and the changegroup
11476 ** contain changes that apply to a single row, the final contents of the
11477 ** changegroup depends on the type of each change, as follows:
11478 **
11479 ** <table border=1 style="margin-left:8ex;margin-right:8ex">
11480 **   <tr><th style="white-space:pre">Existing Change  </th>
11481 **       <th style="white-space:pre">New Change       </th>
11482 **       <th>Output Change
11483 **   <tr><td>INSERT <td>INSERT <td>
11484 **       The new change is ignored. This case does not occur if the new
11485 **       changeset was recorded immediately after the changesets already
11486 **       added to the changegroup.
11487 **   <tr><td>INSERT <td>UPDATE <td>
11488 **       The INSERT change remains in the changegroup. The values in the
11489 **       INSERT change are modified as if the row was inserted by the
11490 **       existing change and then updated according to the new change.
11491 **   <tr><td>INSERT <td>DELETE <td>
11492 **       The existing INSERT is removed from the changegroup. The DELETE is
11493 **       not added.
11494 **   <tr><td>UPDATE <td>INSERT <td>
11495 **       The new change is ignored. This case does not occur if the new
11496 **       changeset was recorded immediately after the changesets already
11497 **       added to the changegroup.
11498 **   <tr><td>UPDATE <td>UPDATE <td>
11499 **       The existing UPDATE remains within the changegroup. It is amended
11500 **       so that the accompanying values are as if the row was updated once
11501 **       by the existing change and then again by the new change.
11502 **   <tr><td>UPDATE <td>DELETE <td>
11503 **       The existing UPDATE is replaced by the new DELETE within the
11504 **       changegroup.
11505 **   <tr><td>DELETE <td>INSERT <td>
11506 **       If one or more of the column values in the row inserted by the
11507 **       new change differ from those in the row deleted by the existing
11508 **       change, the existing DELETE is replaced by an UPDATE within the
11509 **       changegroup. Otherwise, if the inserted row is exactly the same
11510 **       as the deleted row, the existing DELETE is simply discarded.
11511 **   <tr><td>DELETE <td>UPDATE <td>
11512 **       The new change is ignored. This case does not occur if the new
11513 **       changeset was recorded immediately after the changesets already
11514 **       added to the changegroup.
11515 **   <tr><td>DELETE <td>DELETE <td>
11516 **       The new change is ignored. This case does not occur if the new
11517 **       changeset was recorded immediately after the changesets already
11518 **       added to the changegroup.
11519 ** </table>
11520 **
11521 ** If the new changeset contains changes to a table that is already present
11522 ** in the changegroup, then the number of columns and the position of the
11523 ** primary key columns for the table must be consistent. If this is not the
11524 ** case, this function fails with SQLITE_SCHEMA. If the input changeset
11525 ** appears to be corrupt and the corruption is detected, SQLITE_CORRUPT is
11526 ** returned. Or, if an out-of-memory condition occurs during processing, this
11527 ** function returns SQLITE_NOMEM. In all cases, if an error occurs the state
11528 ** of the final contents of the changegroup is undefined.
11529 **
11530 ** If no error occurs, SQLITE_OK is returned.
11531 */
11532 SQLITE_API int sqlite3changegroup_add(sqlite3_changegroup*, int nData, void *pData);
11533 
11534 /*
11535 ** CAPI3REF: Obtain A Composite Changeset From A Changegroup
11536 ** METHOD: sqlite3_changegroup
11537 **
11538 ** Obtain a buffer containing a changeset (or patchset) representing the
11539 ** current contents of the changegroup. If the inputs to the changegroup
11540 ** were themselves changesets, the output is a changeset. Or, if the
11541 ** inputs were patchsets, the output is also a patchset.
11542 **
11543 ** As with the output of the sqlite3session_changeset() and
11544 ** sqlite3session_patchset() functions, all changes related to a single
11545 ** table are grouped together in the output of this function. Tables appear
11546 ** in the same order as for the very first changeset added to the changegroup.
11547 ** If the second or subsequent changesets added to the changegroup contain
11548 ** changes for tables that do not appear in the first changeset, they are
11549 ** appended onto the end of the output changeset, again in the order in
11550 ** which they are first encountered.
11551 **
11552 ** If an error occurs, an SQLite error code is returned and the output
11553 ** variables (*pnData) and (*ppData) are set to 0. Otherwise, SQLITE_OK
11554 ** is returned and the output variables are set to the size of and a
11555 ** pointer to the output buffer, respectively. In this case it is the
11556 ** responsibility of the caller to eventually free the buffer using a
11557 ** call to sqlite3_free().
11558 */
11559 SQLITE_API int sqlite3changegroup_output(
11560   sqlite3_changegroup*,
11561   int *pnData,                    /* OUT: Size of output buffer in bytes */
11562   void **ppData                   /* OUT: Pointer to output buffer */
11563 );
11564 
11565 /*
11566 ** CAPI3REF: Delete A Changegroup Object
11567 ** DESTRUCTOR: sqlite3_changegroup
11568 */
11569 SQLITE_API void sqlite3changegroup_delete(sqlite3_changegroup*);
11570 
11571 /*
11572 ** CAPI3REF: Apply A Changeset To A Database
11573 **
11574 ** Apply a changeset or patchset to a database. These functions attempt to
11575 ** update the "main" database attached to handle db with the changes found in
11576 ** the changeset passed via the second and third arguments.
11577 **
11578 ** The fourth argument (xFilter) passed to these functions is the "filter
11579 ** callback". If it is not NULL, then for each table affected by at least one
11580 ** change in the changeset, the filter callback is invoked with
11581 ** the table name as the second argument, and a copy of the context pointer
11582 ** passed as the sixth argument as the first. If the "filter callback"
11583 ** returns zero, then no attempt is made to apply any changes to the table.
11584 ** Otherwise, if the return value is non-zero or the xFilter argument to
11585 ** is NULL, all changes related to the table are attempted.
11586 **
11587 ** For each table that is not excluded by the filter callback, this function
11588 ** tests that the target database contains a compatible table. A table is
11589 ** considered compatible if all of the following are true:
11590 **
11591 ** <ul>
11592 **   <li> The table has the same name as the name recorded in the
11593 **        changeset, and
11594 **   <li> The table has at least as many columns as recorded in the
11595 **        changeset, and
11596 **   <li> The table has primary key columns in the same position as
11597 **        recorded in the changeset.
11598 ** </ul>
11599 **
11600 ** If there is no compatible table, it is not an error, but none of the
11601 ** changes associated with the table are applied. A warning message is issued
11602 ** via the sqlite3_log() mechanism with the error code SQLITE_SCHEMA. At most
11603 ** one such warning is issued for each table in the changeset.
11604 **
11605 ** For each change for which there is a compatible table, an attempt is made
11606 ** to modify the table contents according to the UPDATE, INSERT or DELETE
11607 ** change. If a change cannot be applied cleanly, the conflict handler
11608 ** function passed as the fifth argument to sqlite3changeset_apply() may be
11609 ** invoked. A description of exactly when the conflict handler is invoked for
11610 ** each type of change is below.
11611 **
11612 ** Unlike the xFilter argument, xConflict may not be passed NULL. The results
11613 ** of passing anything other than a valid function pointer as the xConflict
11614 ** argument are undefined.
11615 **
11616 ** Each time the conflict handler function is invoked, it must return one
11617 ** of [SQLITE_CHANGESET_OMIT], [SQLITE_CHANGESET_ABORT] or
11618 ** [SQLITE_CHANGESET_REPLACE]. SQLITE_CHANGESET_REPLACE may only be returned
11619 ** if the second argument passed to the conflict handler is either
11620 ** SQLITE_CHANGESET_DATA or SQLITE_CHANGESET_CONFLICT. If the conflict-handler
11621 ** returns an illegal value, any changes already made are rolled back and
11622 ** the call to sqlite3changeset_apply() returns SQLITE_MISUSE. Different
11623 ** actions are taken by sqlite3changeset_apply() depending on the value
11624 ** returned by each invocation of the conflict-handler function. Refer to
11625 ** the documentation for the three
11626 ** [SQLITE_CHANGESET_OMIT|available return values] for details.
11627 **
11628 ** <dl>
11629 ** <dt>DELETE Changes<dd>
11630 **   For each DELETE change, the function checks if the target database
11631 **   contains a row with the same primary key value (or values) as the
11632 **   original row values stored in the changeset. If it does, and the values
11633 **   stored in all non-primary key columns also match the values stored in
11634 **   the changeset the row is deleted from the target database.
11635 **
11636 **   If a row with matching primary key values is found, but one or more of
11637 **   the non-primary key fields contains a value different from the original
11638 **   row value stored in the changeset, the conflict-handler function is
11639 **   invoked with [SQLITE_CHANGESET_DATA] as the second argument. If the
11640 **   database table has more columns than are recorded in the changeset,
11641 **   only the values of those non-primary key fields are compared against
11642 **   the current database contents - any trailing database table columns
11643 **   are ignored.
11644 **
11645 **   If no row with matching primary key values is found in the database,
11646 **   the conflict-handler function is invoked with [SQLITE_CHANGESET_NOTFOUND]
11647 **   passed as the second argument.
11648 **
11649 **   If the DELETE operation is attempted, but SQLite returns SQLITE_CONSTRAINT
11650 **   (which can only happen if a foreign key constraint is violated), the
11651 **   conflict-handler function is invoked with [SQLITE_CHANGESET_CONSTRAINT]
11652 **   passed as the second argument. This includes the case where the DELETE
11653 **   operation is attempted because an earlier call to the conflict handler
11654 **   function returned [SQLITE_CHANGESET_REPLACE].
11655 **
11656 ** <dt>INSERT Changes<dd>
11657 **   For each INSERT change, an attempt is made to insert the new row into
11658 **   the database. If the changeset row contains fewer fields than the
11659 **   database table, the trailing fields are populated with their default
11660 **   values.
11661 **
11662 **   If the attempt to insert the row fails because the database already
11663 **   contains a row with the same primary key values, the conflict handler
11664 **   function is invoked with the second argument set to
11665 **   [SQLITE_CHANGESET_CONFLICT].
11666 **
11667 **   If the attempt to insert the row fails because of some other constraint
11668 **   violation (e.g. NOT NULL or UNIQUE), the conflict handler function is
11669 **   invoked with the second argument set to [SQLITE_CHANGESET_CONSTRAINT].
11670 **   This includes the case where the INSERT operation is re-attempted because
11671 **   an earlier call to the conflict handler function returned
11672 **   [SQLITE_CHANGESET_REPLACE].
11673 **
11674 ** <dt>UPDATE Changes<dd>
11675 **   For each UPDATE change, the function checks if the target database
11676 **   contains a row with the same primary key value (or values) as the
11677 **   original row values stored in the changeset. If it does, and the values
11678 **   stored in all modified non-primary key columns also match the values
11679 **   stored in the changeset the row is updated within the target database.
11680 **
11681 **   If a row with matching primary key values is found, but one or more of
11682 **   the modified non-primary key fields contains a value different from an
11683 **   original row value stored in the changeset, the conflict-handler function
11684 **   is invoked with [SQLITE_CHANGESET_DATA] as the second argument. Since
11685 **   UPDATE changes only contain values for non-primary key fields that are
11686 **   to be modified, only those fields need to match the original values to
11687 **   avoid the SQLITE_CHANGESET_DATA conflict-handler callback.
11688 **
11689 **   If no row with matching primary key values is found in the database,
11690 **   the conflict-handler function is invoked with [SQLITE_CHANGESET_NOTFOUND]
11691 **   passed as the second argument.
11692 **
11693 **   If the UPDATE operation is attempted, but SQLite returns
11694 **   SQLITE_CONSTRAINT, the conflict-handler function is invoked with
11695 **   [SQLITE_CHANGESET_CONSTRAINT] passed as the second argument.
11696 **   This includes the case where the UPDATE operation is attempted after
11697 **   an earlier call to the conflict handler function returned
11698 **   [SQLITE_CHANGESET_REPLACE].
11699 ** </dl>
11700 **
11701 ** It is safe to execute SQL statements, including those that write to the
11702 ** table that the callback related to, from within the xConflict callback.
11703 ** This can be used to further customize the application's conflict
11704 ** resolution strategy.
11705 **
11706 ** All changes made by these functions are enclosed in a savepoint transaction.
11707 ** If any other error (aside from a constraint failure when attempting to
11708 ** write to the target database) occurs, then the savepoint transaction is
11709 ** rolled back, restoring the target database to its original state, and an
11710 ** SQLite error code returned.
11711 **
11712 ** If the output parameters (ppRebase) and (pnRebase) are non-NULL and
11713 ** the input is a changeset (not a patchset), then sqlite3changeset_apply_v2()
11714 ** may set (*ppRebase) to point to a "rebase" that may be used with the
11715 ** sqlite3_rebaser APIs buffer before returning. In this case (*pnRebase)
11716 ** is set to the size of the buffer in bytes. It is the responsibility of the
11717 ** caller to eventually free any such buffer using sqlite3_free(). The buffer
11718 ** is only allocated and populated if one or more conflicts were encountered
11719 ** while applying the patchset. See comments surrounding the sqlite3_rebaser
11720 ** APIs for further details.
11721 **
11722 ** The behavior of sqlite3changeset_apply_v2() and its streaming equivalent
11723 ** may be modified by passing a combination of
11724 ** [SQLITE_CHANGESETAPPLY_NOSAVEPOINT | supported flags] as the 9th parameter.
11725 **
11726 ** Note that the sqlite3changeset_apply_v2() API is still <b>experimental</b>
11727 ** and therefore subject to change.
11728 */
11729 SQLITE_API int sqlite3changeset_apply(
11730   sqlite3 *db,                    /* Apply change to "main" db of this handle */
11731   int nChangeset,                 /* Size of changeset in bytes */
11732   void *pChangeset,               /* Changeset blob */
11733   int(*xFilter)(
11734     void *pCtx,                   /* Copy of sixth arg to _apply() */
11735     const char *zTab              /* Table name */
11736   ),
11737   int(*xConflict)(
11738     void *pCtx,                   /* Copy of sixth arg to _apply() */
11739     int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
11740     sqlite3_changeset_iter *p     /* Handle describing change and conflict */
11741   ),
11742   void *pCtx                      /* First argument passed to xConflict */
11743 );
11744 SQLITE_API int sqlite3changeset_apply_v2(
11745   sqlite3 *db,                    /* Apply change to "main" db of this handle */
11746   int nChangeset,                 /* Size of changeset in bytes */
11747   void *pChangeset,               /* Changeset blob */
11748   int(*xFilter)(
11749     void *pCtx,                   /* Copy of sixth arg to _apply() */
11750     const char *zTab              /* Table name */
11751   ),
11752   int(*xConflict)(
11753     void *pCtx,                   /* Copy of sixth arg to _apply() */
11754     int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
11755     sqlite3_changeset_iter *p     /* Handle describing change and conflict */
11756   ),
11757   void *pCtx,                     /* First argument passed to xConflict */
11758   void **ppRebase, int *pnRebase, /* OUT: Rebase data */
11759   int flags                       /* SESSION_CHANGESETAPPLY_* flags */
11760 );
11761 
11762 /*
11763 ** CAPI3REF: Flags for sqlite3changeset_apply_v2
11764 **
11765 ** The following flags may passed via the 9th parameter to
11766 ** [sqlite3changeset_apply_v2] and [sqlite3changeset_apply_v2_strm]:
11767 **
11768 ** <dl>
11769 ** <dt>SQLITE_CHANGESETAPPLY_NOSAVEPOINT <dd>
11770 **   Usually, the sessions module encloses all operations performed by
11771 **   a single call to apply_v2() or apply_v2_strm() in a [SAVEPOINT]. The
11772 **   SAVEPOINT is committed if the changeset or patchset is successfully
11773 **   applied, or rolled back if an error occurs. Specifying this flag
11774 **   causes the sessions module to omit this savepoint. In this case, if the
11775 **   caller has an open transaction or savepoint when apply_v2() is called,
11776 **   it may revert the partially applied changeset by rolling it back.
11777 **
11778 ** <dt>SQLITE_CHANGESETAPPLY_INVERT <dd>
11779 **   Invert the changeset before applying it. This is equivalent to inverting
11780 **   a changeset using sqlite3changeset_invert() before applying it. It is
11781 **   an error to specify this flag with a patchset.
11782 */
11783 #define SQLITE_CHANGESETAPPLY_NOSAVEPOINT   0x0001
11784 #define SQLITE_CHANGESETAPPLY_INVERT        0x0002
11785 
11786 /*
11787 ** CAPI3REF: Constants Passed To The Conflict Handler
11788 **
11789 ** Values that may be passed as the second argument to a conflict-handler.
11790 **
11791 ** <dl>
11792 ** <dt>SQLITE_CHANGESET_DATA<dd>
11793 **   The conflict handler is invoked with CHANGESET_DATA as the second argument
11794 **   when processing a DELETE or UPDATE change if a row with the required
11795 **   PRIMARY KEY fields is present in the database, but one or more other
11796 **   (non primary-key) fields modified by the update do not contain the
11797 **   expected "before" values.
11798 **
11799 **   The conflicting row, in this case, is the database row with the matching
11800 **   primary key.
11801 **
11802 ** <dt>SQLITE_CHANGESET_NOTFOUND<dd>
11803 **   The conflict handler is invoked with CHANGESET_NOTFOUND as the second
11804 **   argument when processing a DELETE or UPDATE change if a row with the
11805 **   required PRIMARY KEY fields is not present in the database.
11806 **
11807 **   There is no conflicting row in this case. The results of invoking the
11808 **   sqlite3changeset_conflict() API are undefined.
11809 **
11810 ** <dt>SQLITE_CHANGESET_CONFLICT<dd>
11811 **   CHANGESET_CONFLICT is passed as the second argument to the conflict
11812 **   handler while processing an INSERT change if the operation would result
11813 **   in duplicate primary key values.
11814 **
11815 **   The conflicting row in this case is the database row with the matching
11816 **   primary key.
11817 **
11818 ** <dt>SQLITE_CHANGESET_FOREIGN_KEY<dd>
11819 **   If foreign key handling is enabled, and applying a changeset leaves the
11820 **   database in a state containing foreign key violations, the conflict
11821 **   handler is invoked with CHANGESET_FOREIGN_KEY as the second argument
11822 **   exactly once before the changeset is committed. If the conflict handler
11823 **   returns CHANGESET_OMIT, the changes, including those that caused the
11824 **   foreign key constraint violation, are committed. Or, if it returns
11825 **   CHANGESET_ABORT, the changeset is rolled back.
11826 **
11827 **   No current or conflicting row information is provided. The only function
11828 **   it is possible to call on the supplied sqlite3_changeset_iter handle
11829 **   is sqlite3changeset_fk_conflicts().
11830 **
11831 ** <dt>SQLITE_CHANGESET_CONSTRAINT<dd>
11832 **   If any other constraint violation occurs while applying a change (i.e.
11833 **   a UNIQUE, CHECK or NOT NULL constraint), the conflict handler is
11834 **   invoked with CHANGESET_CONSTRAINT as the second argument.
11835 **
11836 **   There is no conflicting row in this case. The results of invoking the
11837 **   sqlite3changeset_conflict() API are undefined.
11838 **
11839 ** </dl>
11840 */
11841 #define SQLITE_CHANGESET_DATA        1
11842 #define SQLITE_CHANGESET_NOTFOUND    2
11843 #define SQLITE_CHANGESET_CONFLICT    3
11844 #define SQLITE_CHANGESET_CONSTRAINT  4
11845 #define SQLITE_CHANGESET_FOREIGN_KEY 5
11846 
11847 /*
11848 ** CAPI3REF: Constants Returned By The Conflict Handler
11849 **
11850 ** A conflict handler callback must return one of the following three values.
11851 **
11852 ** <dl>
11853 ** <dt>SQLITE_CHANGESET_OMIT<dd>
11854 **   If a conflict handler returns this value no special action is taken. The
11855 **   change that caused the conflict is not applied. The session module
11856 **   continues to the next change in the changeset.
11857 **
11858 ** <dt>SQLITE_CHANGESET_REPLACE<dd>
11859 **   This value may only be returned if the second argument to the conflict
11860 **   handler was SQLITE_CHANGESET_DATA or SQLITE_CHANGESET_CONFLICT. If this
11861 **   is not the case, any changes applied so far are rolled back and the
11862 **   call to sqlite3changeset_apply() returns SQLITE_MISUSE.
11863 **
11864 **   If CHANGESET_REPLACE is returned by an SQLITE_CHANGESET_DATA conflict
11865 **   handler, then the conflicting row is either updated or deleted, depending
11866 **   on the type of change.
11867 **
11868 **   If CHANGESET_REPLACE is returned by an SQLITE_CHANGESET_CONFLICT conflict
11869 **   handler, then the conflicting row is removed from the database and a
11870 **   second attempt to apply the change is made. If this second attempt fails,
11871 **   the original row is restored to the database before continuing.
11872 **
11873 ** <dt>SQLITE_CHANGESET_ABORT<dd>
11874 **   If this value is returned, any changes applied so far are rolled back
11875 **   and the call to sqlite3changeset_apply() returns SQLITE_ABORT.
11876 ** </dl>
11877 */
11878 #define SQLITE_CHANGESET_OMIT       0
11879 #define SQLITE_CHANGESET_REPLACE    1
11880 #define SQLITE_CHANGESET_ABORT      2
11881 
11882 /*
11883 ** CAPI3REF: Rebasing changesets
11884 ** EXPERIMENTAL
11885 **
11886 ** Suppose there is a site hosting a database in state S0. And that
11887 ** modifications are made that move that database to state S1 and a
11888 ** changeset recorded (the "local" changeset). Then, a changeset based
11889 ** on S0 is received from another site (the "remote" changeset) and
11890 ** applied to the database. The database is then in state
11891 ** (S1+"remote"), where the exact state depends on any conflict
11892 ** resolution decisions (OMIT or REPLACE) made while applying "remote".
11893 ** Rebasing a changeset is to update it to take those conflict
11894 ** resolution decisions into account, so that the same conflicts
11895 ** do not have to be resolved elsewhere in the network.
11896 **
11897 ** For example, if both the local and remote changesets contain an
11898 ** INSERT of the same key on "CREATE TABLE t1(a PRIMARY KEY, b)":
11899 **
11900 **   local:  INSERT INTO t1 VALUES(1, 'v1');
11901 **   remote: INSERT INTO t1 VALUES(1, 'v2');
11902 **
11903 ** and the conflict resolution is REPLACE, then the INSERT change is
11904 ** removed from the local changeset (it was overridden). Or, if the
11905 ** conflict resolution was "OMIT", then the local changeset is modified
11906 ** to instead contain:
11907 **
11908 **           UPDATE t1 SET b = 'v2' WHERE a=1;
11909 **
11910 ** Changes within the local changeset are rebased as follows:
11911 **
11912 ** <dl>
11913 ** <dt>Local INSERT<dd>
11914 **   This may only conflict with a remote INSERT. If the conflict
11915 **   resolution was OMIT, then add an UPDATE change to the rebased
11916 **   changeset. Or, if the conflict resolution was REPLACE, add
11917 **   nothing to the rebased changeset.
11918 **
11919 ** <dt>Local DELETE<dd>
11920 **   This may conflict with a remote UPDATE or DELETE. In both cases the
11921 **   only possible resolution is OMIT. If the remote operation was a
11922 **   DELETE, then add no change to the rebased changeset. If the remote
11923 **   operation was an UPDATE, then the old.* fields of change are updated
11924 **   to reflect the new.* values in the UPDATE.
11925 **
11926 ** <dt>Local UPDATE<dd>
11927 **   This may conflict with a remote UPDATE or DELETE. If it conflicts
11928 **   with a DELETE, and the conflict resolution was OMIT, then the update
11929 **   is changed into an INSERT. Any undefined values in the new.* record
11930 **   from the update change are filled in using the old.* values from
11931 **   the conflicting DELETE. Or, if the conflict resolution was REPLACE,
11932 **   the UPDATE change is simply omitted from the rebased changeset.
11933 **
11934 **   If conflict is with a remote UPDATE and the resolution is OMIT, then
11935 **   the old.* values are rebased using the new.* values in the remote
11936 **   change. Or, if the resolution is REPLACE, then the change is copied
11937 **   into the rebased changeset with updates to columns also updated by
11938 **   the conflicting remote UPDATE removed. If this means no columns would
11939 **   be updated, the change is omitted.
11940 ** </dl>
11941 **
11942 ** A local change may be rebased against multiple remote changes
11943 ** simultaneously. If a single key is modified by multiple remote
11944 ** changesets, they are combined as follows before the local changeset
11945 ** is rebased:
11946 **
11947 ** <ul>
11948 **    <li> If there has been one or more REPLACE resolutions on a
11949 **         key, it is rebased according to a REPLACE.
11950 **
11951 **    <li> If there have been no REPLACE resolutions on a key, then
11952 **         the local changeset is rebased according to the most recent
11953 **         of the OMIT resolutions.
11954 ** </ul>
11955 **
11956 ** Note that conflict resolutions from multiple remote changesets are
11957 ** combined on a per-field basis, not per-row. This means that in the
11958 ** case of multiple remote UPDATE operations, some fields of a single
11959 ** local change may be rebased for REPLACE while others are rebased for
11960 ** OMIT.
11961 **
11962 ** In order to rebase a local changeset, the remote changeset must first
11963 ** be applied to the local database using sqlite3changeset_apply_v2() and
11964 ** the buffer of rebase information captured. Then:
11965 **
11966 ** <ol>
11967 **   <li> An sqlite3_rebaser object is created by calling
11968 **        sqlite3rebaser_create().
11969 **   <li> The new object is configured with the rebase buffer obtained from
11970 **        sqlite3changeset_apply_v2() by calling sqlite3rebaser_configure().
11971 **        If the local changeset is to be rebased against multiple remote
11972 **        changesets, then sqlite3rebaser_configure() should be called
11973 **        multiple times, in the same order that the multiple
11974 **        sqlite3changeset_apply_v2() calls were made.
11975 **   <li> Each local changeset is rebased by calling sqlite3rebaser_rebase().
11976 **   <li> The sqlite3_rebaser object is deleted by calling
11977 **        sqlite3rebaser_delete().
11978 ** </ol>
11979 */
11980 typedef struct sqlite3_rebaser sqlite3_rebaser;
11981 
11982 /*
11983 ** CAPI3REF: Create a changeset rebaser object.
11984 ** EXPERIMENTAL
11985 **
11986 ** Allocate a new changeset rebaser object. If successful, set (*ppNew) to
11987 ** point to the new object and return SQLITE_OK. Otherwise, if an error
11988 ** occurs, return an SQLite error code (e.g. SQLITE_NOMEM) and set (*ppNew)
11989 ** to NULL.
11990 */
11991 SQLITE_API int sqlite3rebaser_create(sqlite3_rebaser **ppNew);
11992 
11993 /*
11994 ** CAPI3REF: Configure a changeset rebaser object.
11995 ** EXPERIMENTAL
11996 **
11997 ** Configure the changeset rebaser object to rebase changesets according
11998 ** to the conflict resolutions described by buffer pRebase (size nRebase
11999 ** bytes), which must have been obtained from a previous call to
12000 ** sqlite3changeset_apply_v2().
12001 */
12002 SQLITE_API int sqlite3rebaser_configure(
12003   sqlite3_rebaser*,
12004   int nRebase, const void *pRebase
12005 );
12006 
12007 /*
12008 ** CAPI3REF: Rebase a changeset
12009 ** EXPERIMENTAL
12010 **
12011 ** Argument pIn must point to a buffer containing a changeset nIn bytes
12012 ** in size. This function allocates and populates a buffer with a copy
12013 ** of the changeset rebased according to the configuration of the
12014 ** rebaser object passed as the first argument. If successful, (*ppOut)
12015 ** is set to point to the new buffer containing the rebased changeset and
12016 ** (*pnOut) to its size in bytes and SQLITE_OK returned. It is the
12017 ** responsibility of the caller to eventually free the new buffer using
12018 ** sqlite3_free(). Otherwise, if an error occurs, (*ppOut) and (*pnOut)
12019 ** are set to zero and an SQLite error code returned.
12020 */
12021 SQLITE_API int sqlite3rebaser_rebase(
12022   sqlite3_rebaser*,
12023   int nIn, const void *pIn,
12024   int *pnOut, void **ppOut
12025 );
12026 
12027 /*
12028 ** CAPI3REF: Delete a changeset rebaser object.
12029 ** EXPERIMENTAL
12030 **
12031 ** Delete the changeset rebaser object and all associated resources. There
12032 ** should be one call to this function for each successful invocation
12033 ** of sqlite3rebaser_create().
12034 */
12035 SQLITE_API void sqlite3rebaser_delete(sqlite3_rebaser *p);
12036 
12037 /*
12038 ** CAPI3REF: Streaming Versions of API functions.
12039 **
12040 ** The six streaming API xxx_strm() functions serve similar purposes to the
12041 ** corresponding non-streaming API functions:
12042 **
12043 ** <table border=1 style="margin-left:8ex;margin-right:8ex">
12044 **   <tr><th>Streaming function<th>Non-streaming equivalent</th>
12045 **   <tr><td>sqlite3changeset_apply_strm<td>[sqlite3changeset_apply]
12046 **   <tr><td>sqlite3changeset_apply_strm_v2<td>[sqlite3changeset_apply_v2]
12047 **   <tr><td>sqlite3changeset_concat_strm<td>[sqlite3changeset_concat]
12048 **   <tr><td>sqlite3changeset_invert_strm<td>[sqlite3changeset_invert]
12049 **   <tr><td>sqlite3changeset_start_strm<td>[sqlite3changeset_start]
12050 **   <tr><td>sqlite3session_changeset_strm<td>[sqlite3session_changeset]
12051 **   <tr><td>sqlite3session_patchset_strm<td>[sqlite3session_patchset]
12052 ** </table>
12053 **
12054 ** Non-streaming functions that accept changesets (or patchsets) as input
12055 ** require that the entire changeset be stored in a single buffer in memory.
12056 ** Similarly, those that return a changeset or patchset do so by returning
12057 ** a pointer to a single large buffer allocated using sqlite3_malloc().
12058 ** Normally this is convenient. However, if an application running in a
12059 ** low-memory environment is required to handle very large changesets, the
12060 ** large contiguous memory allocations required can become onerous.
12061 **
12062 ** In order to avoid this problem, instead of a single large buffer, input
12063 ** is passed to a streaming API functions by way of a callback function that
12064 ** the sessions module invokes to incrementally request input data as it is
12065 ** required. In all cases, a pair of API function parameters such as
12066 **
12067 **  <pre>
12068 **  &nbsp;     int nChangeset,
12069 **  &nbsp;     void *pChangeset,
12070 **  </pre>
12071 **
12072 ** Is replaced by:
12073 **
12074 **  <pre>
12075 **  &nbsp;     int (*xInput)(void *pIn, void *pData, int *pnData),
12076 **  &nbsp;     void *pIn,
12077 **  </pre>
12078 **
12079 ** Each time the xInput callback is invoked by the sessions module, the first
12080 ** argument passed is a copy of the supplied pIn context pointer. The second
12081 ** argument, pData, points to a buffer (*pnData) bytes in size. Assuming no
12082 ** error occurs the xInput method should copy up to (*pnData) bytes of data
12083 ** into the buffer and set (*pnData) to the actual number of bytes copied
12084 ** before returning SQLITE_OK. If the input is completely exhausted, (*pnData)
12085 ** should be set to zero to indicate this. Or, if an error occurs, an SQLite
12086 ** error code should be returned. In all cases, if an xInput callback returns
12087 ** an error, all processing is abandoned and the streaming API function
12088 ** returns a copy of the error code to the caller.
12089 **
12090 ** In the case of sqlite3changeset_start_strm(), the xInput callback may be
12091 ** invoked by the sessions module at any point during the lifetime of the
12092 ** iterator. If such an xInput callback returns an error, the iterator enters
12093 ** an error state, whereby all subsequent calls to iterator functions
12094 ** immediately fail with the same error code as returned by xInput.
12095 **
12096 ** Similarly, streaming API functions that return changesets (or patchsets)
12097 ** return them in chunks by way of a callback function instead of via a
12098 ** pointer to a single large buffer. In this case, a pair of parameters such
12099 ** as:
12100 **
12101 **  <pre>
12102 **  &nbsp;     int *pnChangeset,
12103 **  &nbsp;     void **ppChangeset,
12104 **  </pre>
12105 **
12106 ** Is replaced by:
12107 **
12108 **  <pre>
12109 **  &nbsp;     int (*xOutput)(void *pOut, const void *pData, int nData),
12110 **  &nbsp;     void *pOut
12111 **  </pre>
12112 **
12113 ** The xOutput callback is invoked zero or more times to return data to
12114 ** the application. The first parameter passed to each call is a copy of the
12115 ** pOut pointer supplied by the application. The second parameter, pData,
12116 ** points to a buffer nData bytes in size containing the chunk of output
12117 ** data being returned. If the xOutput callback successfully processes the
12118 ** supplied data, it should return SQLITE_OK to indicate success. Otherwise,
12119 ** it should return some other SQLite error code. In this case processing
12120 ** is immediately abandoned and the streaming API function returns a copy
12121 ** of the xOutput error code to the application.
12122 **
12123 ** The sessions module never invokes an xOutput callback with the third
12124 ** parameter set to a value less than or equal to zero. Other than this,
12125 ** no guarantees are made as to the size of the chunks of data returned.
12126 */
12127 SQLITE_API int sqlite3changeset_apply_strm(
12128   sqlite3 *db,                    /* Apply change to "main" db of this handle */
12129   int (*xInput)(void *pIn, void *pData, int *pnData), /* Input function */
12130   void *pIn,                                          /* First arg for xInput */
12131   int(*xFilter)(
12132     void *pCtx,                   /* Copy of sixth arg to _apply() */
12133     const char *zTab              /* Table name */
12134   ),
12135   int(*xConflict)(
12136     void *pCtx,                   /* Copy of sixth arg to _apply() */
12137     int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
12138     sqlite3_changeset_iter *p     /* Handle describing change and conflict */
12139   ),
12140   void *pCtx                      /* First argument passed to xConflict */
12141 );
12142 SQLITE_API int sqlite3changeset_apply_v2_strm(
12143   sqlite3 *db,                    /* Apply change to "main" db of this handle */
12144   int (*xInput)(void *pIn, void *pData, int *pnData), /* Input function */
12145   void *pIn,                                          /* First arg for xInput */
12146   int(*xFilter)(
12147     void *pCtx,                   /* Copy of sixth arg to _apply() */
12148     const char *zTab              /* Table name */
12149   ),
12150   int(*xConflict)(
12151     void *pCtx,                   /* Copy of sixth arg to _apply() */
12152     int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
12153     sqlite3_changeset_iter *p     /* Handle describing change and conflict */
12154   ),
12155   void *pCtx,                     /* First argument passed to xConflict */
12156   void **ppRebase, int *pnRebase,
12157   int flags
12158 );
12159 SQLITE_API int sqlite3changeset_concat_strm(
12160   int (*xInputA)(void *pIn, void *pData, int *pnData),
12161   void *pInA,
12162   int (*xInputB)(void *pIn, void *pData, int *pnData),
12163   void *pInB,
12164   int (*xOutput)(void *pOut, const void *pData, int nData),
12165   void *pOut
12166 );
12167 SQLITE_API int sqlite3changeset_invert_strm(
12168   int (*xInput)(void *pIn, void *pData, int *pnData),
12169   void *pIn,
12170   int (*xOutput)(void *pOut, const void *pData, int nData),
12171   void *pOut
12172 );
12173 SQLITE_API int sqlite3changeset_start_strm(
12174   sqlite3_changeset_iter **pp,
12175   int (*xInput)(void *pIn, void *pData, int *pnData),
12176   void *pIn
12177 );
12178 SQLITE_API int sqlite3changeset_start_v2_strm(
12179   sqlite3_changeset_iter **pp,
12180   int (*xInput)(void *pIn, void *pData, int *pnData),
12181   void *pIn,
12182   int flags
12183 );
12184 SQLITE_API int sqlite3session_changeset_strm(
12185   sqlite3_session *pSession,
12186   int (*xOutput)(void *pOut, const void *pData, int nData),
12187   void *pOut
12188 );
12189 SQLITE_API int sqlite3session_patchset_strm(
12190   sqlite3_session *pSession,
12191   int (*xOutput)(void *pOut, const void *pData, int nData),
12192   void *pOut
12193 );
12194 SQLITE_API int sqlite3changegroup_add_strm(sqlite3_changegroup*,
12195     int (*xInput)(void *pIn, void *pData, int *pnData),
12196     void *pIn
12197 );
12198 SQLITE_API int sqlite3changegroup_output_strm(sqlite3_changegroup*,
12199     int (*xOutput)(void *pOut, const void *pData, int nData),
12200     void *pOut
12201 );
12202 SQLITE_API int sqlite3rebaser_rebase_strm(
12203   sqlite3_rebaser *pRebaser,
12204   int (*xInput)(void *pIn, void *pData, int *pnData),
12205   void *pIn,
12206   int (*xOutput)(void *pOut, const void *pData, int nData),
12207   void *pOut
12208 );
12209 
12210 /*
12211 ** CAPI3REF: Configure global parameters
12212 **
12213 ** The sqlite3session_config() interface is used to make global configuration
12214 ** changes to the sessions module in order to tune it to the specific needs
12215 ** of the application.
12216 **
12217 ** The sqlite3session_config() interface is not threadsafe. If it is invoked
12218 ** while any other thread is inside any other sessions method then the
12219 ** results are undefined. Furthermore, if it is invoked after any sessions
12220 ** related objects have been created, the results are also undefined.
12221 **
12222 ** The first argument to the sqlite3session_config() function must be one
12223 ** of the SQLITE_SESSION_CONFIG_XXX constants defined below. The
12224 ** interpretation of the (void*) value passed as the second parameter and
12225 ** the effect of calling this function depends on the value of the first
12226 ** parameter.
12227 **
12228 ** <dl>
12229 ** <dt>SQLITE_SESSION_CONFIG_STRMSIZE<dd>
12230 **    By default, the sessions module streaming interfaces attempt to input
12231 **    and output data in approximately 1 KiB chunks. This operand may be used
12232 **    to set and query the value of this configuration setting. The pointer
12233 **    passed as the second argument must point to a value of type (int).
12234 **    If this value is greater than 0, it is used as the new streaming data
12235 **    chunk size for both input and output. Before returning, the (int) value
12236 **    pointed to by pArg is set to the final value of the streaming interface
12237 **    chunk size.
12238 ** </dl>
12239 **
12240 ** This function returns SQLITE_OK if successful, or an SQLite error code
12241 ** otherwise.
12242 */
12243 SQLITE_API int sqlite3session_config(int op, void *pArg);
12244 
12245 /*
12246 ** CAPI3REF: Values for sqlite3session_config().
12247 */
12248 #define SQLITE_SESSION_CONFIG_STRMSIZE 1
12249 
12250 /*
12251 ** Make sure we can call this stuff from C++.
12252 */
12253 #ifdef __cplusplus
12254 }
12255 #endif
12256 
12257 #endif  /* !defined(__SQLITESESSION_H_) && defined(SQLITE_ENABLE_SESSION) */
12258 
12259 /******** End of sqlite3session.h *********/
12260 /******** Begin file fts5.h *********/
12261 /*
12262 ** 2014 May 31
12263 **
12264 ** The author disclaims copyright to this source code.  In place of
12265 ** a legal notice, here is a blessing:
12266 **
12267 **    May you do good and not evil.
12268 **    May you find forgiveness for yourself and forgive others.
12269 **    May you share freely, never taking more than you give.
12270 **
12271 ******************************************************************************
12272 **
12273 ** Interfaces to extend FTS5. Using the interfaces defined in this file,
12274 ** FTS5 may be extended with:
12275 **
12276 **     * custom tokenizers, and
12277 **     * custom auxiliary functions.
12278 */
12279 
12280 
12281 #ifndef _FTS5_H
12282 #define _FTS5_H
12283 
12284 
12285 #ifdef __cplusplus
12286 extern "C" {
12287 #endif
12288 
12289 /*************************************************************************
12290 ** CUSTOM AUXILIARY FUNCTIONS
12291 **
12292 ** Virtual table implementations may overload SQL functions by implementing
12293 ** the sqlite3_module.xFindFunction() method.
12294 */
12295 
12296 typedef struct Fts5ExtensionApi Fts5ExtensionApi;
12297 typedef struct Fts5Context Fts5Context;
12298 typedef struct Fts5PhraseIter Fts5PhraseIter;
12299 
12300 typedef void (*fts5_extension_function)(
12301   const Fts5ExtensionApi *pApi,   /* API offered by current FTS version */
12302   Fts5Context *pFts,              /* First arg to pass to pApi functions */
12303   sqlite3_context *pCtx,          /* Context for returning result/error */
12304   int nVal,                       /* Number of values in apVal[] array */
12305   sqlite3_value **apVal           /* Array of trailing arguments */
12306 );
12307 
12308 struct Fts5PhraseIter {
12309   const unsigned char *a;
12310   const unsigned char *b;
12311 };
12312 
12313 /*
12314 ** EXTENSION API FUNCTIONS
12315 **
12316 ** xUserData(pFts):
12317 **   Return a copy of the context pointer the extension function was
12318 **   registered with.
12319 **
12320 ** xColumnTotalSize(pFts, iCol, pnToken):
12321 **   If parameter iCol is less than zero, set output variable *pnToken
12322 **   to the total number of tokens in the FTS5 table. Or, if iCol is
12323 **   non-negative but less than the number of columns in the table, return
12324 **   the total number of tokens in column iCol, considering all rows in
12325 **   the FTS5 table.
12326 **
12327 **   If parameter iCol is greater than or equal to the number of columns
12328 **   in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g.
12329 **   an OOM condition or IO error), an appropriate SQLite error code is
12330 **   returned.
12331 **
12332 ** xColumnCount(pFts):
12333 **   Return the number of columns in the table.
12334 **
12335 ** xColumnSize(pFts, iCol, pnToken):
12336 **   If parameter iCol is less than zero, set output variable *pnToken
12337 **   to the total number of tokens in the current row. Or, if iCol is
12338 **   non-negative but less than the number of columns in the table, set
12339 **   *pnToken to the number of tokens in column iCol of the current row.
12340 **
12341 **   If parameter iCol is greater than or equal to the number of columns
12342 **   in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g.
12343 **   an OOM condition or IO error), an appropriate SQLite error code is
12344 **   returned.
12345 **
12346 **   This function may be quite inefficient if used with an FTS5 table
12347 **   created with the "columnsize=0" option.
12348 **
12349 ** xColumnText:
12350 **   This function attempts to retrieve the text of column iCol of the
12351 **   current document. If successful, (*pz) is set to point to a buffer
12352 **   containing the text in utf-8 encoding, (*pn) is set to the size in bytes
12353 **   (not characters) of the buffer and SQLITE_OK is returned. Otherwise,
12354 **   if an error occurs, an SQLite error code is returned and the final values
12355 **   of (*pz) and (*pn) are undefined.
12356 **
12357 ** xPhraseCount:
12358 **   Returns the number of phrases in the current query expression.
12359 **
12360 ** xPhraseSize:
12361 **   Returns the number of tokens in phrase iPhrase of the query. Phrases
12362 **   are numbered starting from zero.
12363 **
12364 ** xInstCount:
12365 **   Set *pnInst to the total number of occurrences of all phrases within
12366 **   the query within the current row. Return SQLITE_OK if successful, or
12367 **   an error code (i.e. SQLITE_NOMEM) if an error occurs.
12368 **
12369 **   This API can be quite slow if used with an FTS5 table created with the
12370 **   "detail=none" or "detail=column" option. If the FTS5 table is created
12371 **   with either "detail=none" or "detail=column" and "content=" option
12372 **   (i.e. if it is a contentless table), then this API always returns 0.
12373 **
12374 ** xInst:
12375 **   Query for the details of phrase match iIdx within the current row.
12376 **   Phrase matches are numbered starting from zero, so the iIdx argument
12377 **   should be greater than or equal to zero and smaller than the value
12378 **   output by xInstCount().
12379 **
12380 **   Usually, output parameter *piPhrase is set to the phrase number, *piCol
12381 **   to the column in which it occurs and *piOff the token offset of the
12382 **   first token of the phrase. Returns SQLITE_OK if successful, or an error
12383 **   code (i.e. SQLITE_NOMEM) if an error occurs.
12384 **
12385 **   This API can be quite slow if used with an FTS5 table created with the
12386 **   "detail=none" or "detail=column" option.
12387 **
12388 ** xRowid:
12389 **   Returns the rowid of the current row.
12390 **
12391 ** xTokenize:
12392 **   Tokenize text using the tokenizer belonging to the FTS5 table.
12393 **
12394 ** xQueryPhrase(pFts5, iPhrase, pUserData, xCallback):
12395 **   This API function is used to query the FTS table for phrase iPhrase
12396 **   of the current query. Specifically, a query equivalent to:
12397 **
12398 **       ... FROM ftstable WHERE ftstable MATCH $p ORDER BY rowid
12399 **
12400 **   with $p set to a phrase equivalent to the phrase iPhrase of the
12401 **   current query is executed. Any column filter that applies to
12402 **   phrase iPhrase of the current query is included in $p. For each
12403 **   row visited, the callback function passed as the fourth argument
12404 **   is invoked. The context and API objects passed to the callback
12405 **   function may be used to access the properties of each matched row.
12406 **   Invoking Api.xUserData() returns a copy of the pointer passed as
12407 **   the third argument to pUserData.
12408 **
12409 **   If the callback function returns any value other than SQLITE_OK, the
12410 **   query is abandoned and the xQueryPhrase function returns immediately.
12411 **   If the returned value is SQLITE_DONE, xQueryPhrase returns SQLITE_OK.
12412 **   Otherwise, the error code is propagated upwards.
12413 **
12414 **   If the query runs to completion without incident, SQLITE_OK is returned.
12415 **   Or, if some error occurs before the query completes or is aborted by
12416 **   the callback, an SQLite error code is returned.
12417 **
12418 **
12419 ** xSetAuxdata(pFts5, pAux, xDelete)
12420 **
12421 **   Save the pointer passed as the second argument as the extension function's
12422 **   "auxiliary data". The pointer may then be retrieved by the current or any
12423 **   future invocation of the same fts5 extension function made as part of
12424 **   the same MATCH query using the xGetAuxdata() API.
12425 **
12426 **   Each extension function is allocated a single auxiliary data slot for
12427 **   each FTS query (MATCH expression). If the extension function is invoked
12428 **   more than once for a single FTS query, then all invocations share a
12429 **   single auxiliary data context.
12430 **
12431 **   If there is already an auxiliary data pointer when this function is
12432 **   invoked, then it is replaced by the new pointer. If an xDelete callback
12433 **   was specified along with the original pointer, it is invoked at this
12434 **   point.
12435 **
12436 **   The xDelete callback, if one is specified, is also invoked on the
12437 **   auxiliary data pointer after the FTS5 query has finished.
12438 **
12439 **   If an error (e.g. an OOM condition) occurs within this function,
12440 **   the auxiliary data is set to NULL and an error code returned. If the
12441 **   xDelete parameter was not NULL, it is invoked on the auxiliary data
12442 **   pointer before returning.
12443 **
12444 **
12445 ** xGetAuxdata(pFts5, bClear)
12446 **
12447 **   Returns the current auxiliary data pointer for the fts5 extension
12448 **   function. See the xSetAuxdata() method for details.
12449 **
12450 **   If the bClear argument is non-zero, then the auxiliary data is cleared
12451 **   (set to NULL) before this function returns. In this case the xDelete,
12452 **   if any, is not invoked.
12453 **
12454 **
12455 ** xRowCount(pFts5, pnRow)
12456 **
12457 **   This function is used to retrieve the total number of rows in the table.
12458 **   In other words, the same value that would be returned by:
12459 **
12460 **        SELECT count(*) FROM ftstable;
12461 **
12462 ** xPhraseFirst()
12463 **   This function is used, along with type Fts5PhraseIter and the xPhraseNext
12464 **   method, to iterate through all instances of a single query phrase within
12465 **   the current row. This is the same information as is accessible via the
12466 **   xInstCount/xInst APIs. While the xInstCount/xInst APIs are more convenient
12467 **   to use, this API may be faster under some circumstances. To iterate
12468 **   through instances of phrase iPhrase, use the following code:
12469 **
12470 **       Fts5PhraseIter iter;
12471 **       int iCol, iOff;
12472 **       for(pApi->xPhraseFirst(pFts, iPhrase, &iter, &iCol, &iOff);
12473 **           iCol>=0;
12474 **           pApi->xPhraseNext(pFts, &iter, &iCol, &iOff)
12475 **       ){
12476 **         // An instance of phrase iPhrase at offset iOff of column iCol
12477 **       }
12478 **
12479 **   The Fts5PhraseIter structure is defined above. Applications should not
12480 **   modify this structure directly - it should only be used as shown above
12481 **   with the xPhraseFirst() and xPhraseNext() API methods (and by
12482 **   xPhraseFirstColumn() and xPhraseNextColumn() as illustrated below).
12483 **
12484 **   This API can be quite slow if used with an FTS5 table created with the
12485 **   "detail=none" or "detail=column" option. If the FTS5 table is created
12486 **   with either "detail=none" or "detail=column" and "content=" option
12487 **   (i.e. if it is a contentless table), then this API always iterates
12488 **   through an empty set (all calls to xPhraseFirst() set iCol to -1).
12489 **
12490 ** xPhraseNext()
12491 **   See xPhraseFirst above.
12492 **
12493 ** xPhraseFirstColumn()
12494 **   This function and xPhraseNextColumn() are similar to the xPhraseFirst()
12495 **   and xPhraseNext() APIs described above. The difference is that instead
12496 **   of iterating through all instances of a phrase in the current row, these
12497 **   APIs are used to iterate through the set of columns in the current row
12498 **   that contain one or more instances of a specified phrase. For example:
12499 **
12500 **       Fts5PhraseIter iter;
12501 **       int iCol;
12502 **       for(pApi->xPhraseFirstColumn(pFts, iPhrase, &iter, &iCol);
12503 **           iCol>=0;
12504 **           pApi->xPhraseNextColumn(pFts, &iter, &iCol)
12505 **       ){
12506 **         // Column iCol contains at least one instance of phrase iPhrase
12507 **       }
12508 **
12509 **   This API can be quite slow if used with an FTS5 table created with the
12510 **   "detail=none" option. If the FTS5 table is created with either
12511 **   "detail=none" "content=" option (i.e. if it is a contentless table),
12512 **   then this API always iterates through an empty set (all calls to
12513 **   xPhraseFirstColumn() set iCol to -1).
12514 **
12515 **   The information accessed using this API and its companion
12516 **   xPhraseFirstColumn() may also be obtained using xPhraseFirst/xPhraseNext
12517 **   (or xInst/xInstCount). The chief advantage of this API is that it is
12518 **   significantly more efficient than those alternatives when used with
12519 **   "detail=column" tables.
12520 **
12521 ** xPhraseNextColumn()
12522 **   See xPhraseFirstColumn above.
12523 */
12524 struct Fts5ExtensionApi {
12525   int iVersion;                   /* Currently always set to 3 */
12526 
12527   void *(*xUserData)(Fts5Context*);
12528 
12529   int (*xColumnCount)(Fts5Context*);
12530   int (*xRowCount)(Fts5Context*, sqlite3_int64 *pnRow);
12531   int (*xColumnTotalSize)(Fts5Context*, int iCol, sqlite3_int64 *pnToken);
12532 
12533   int (*xTokenize)(Fts5Context*,
12534     const char *pText, int nText, /* Text to tokenize */
12535     void *pCtx,                   /* Context passed to xToken() */
12536     int (*xToken)(void*, int, const char*, int, int, int)       /* Callback */
12537   );
12538 
12539   int (*xPhraseCount)(Fts5Context*);
12540   int (*xPhraseSize)(Fts5Context*, int iPhrase);
12541 
12542   int (*xInstCount)(Fts5Context*, int *pnInst);
12543   int (*xInst)(Fts5Context*, int iIdx, int *piPhrase, int *piCol, int *piOff);
12544 
12545   sqlite3_int64 (*xRowid)(Fts5Context*);
12546   int (*xColumnText)(Fts5Context*, int iCol, const char **pz, int *pn);
12547   int (*xColumnSize)(Fts5Context*, int iCol, int *pnToken);
12548 
12549   int (*xQueryPhrase)(Fts5Context*, int iPhrase, void *pUserData,
12550     int(*)(const Fts5ExtensionApi*,Fts5Context*,void*)
12551   );
12552   int (*xSetAuxdata)(Fts5Context*, void *pAux, void(*xDelete)(void*));
12553   void *(*xGetAuxdata)(Fts5Context*, int bClear);
12554 
12555   int (*xPhraseFirst)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*, int*);
12556   void (*xPhraseNext)(Fts5Context*, Fts5PhraseIter*, int *piCol, int *piOff);
12557 
12558   int (*xPhraseFirstColumn)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*);
12559   void (*xPhraseNextColumn)(Fts5Context*, Fts5PhraseIter*, int *piCol);
12560 };
12561 
12562 /*
12563 ** CUSTOM AUXILIARY FUNCTIONS
12564 *************************************************************************/
12565 
12566 /*************************************************************************
12567 ** CUSTOM TOKENIZERS
12568 **
12569 ** Applications may also register custom tokenizer types. A tokenizer
12570 ** is registered by providing fts5 with a populated instance of the
12571 ** following structure. All structure methods must be defined, setting
12572 ** any member of the fts5_tokenizer struct to NULL leads to undefined
12573 ** behaviour. The structure methods are expected to function as follows:
12574 **
12575 ** xCreate:
12576 **   This function is used to allocate and initialize a tokenizer instance.
12577 **   A tokenizer instance is required to actually tokenize text.
12578 **
12579 **   The first argument passed to this function is a copy of the (void*)
12580 **   pointer provided by the application when the fts5_tokenizer object
12581 **   was registered with FTS5 (the third argument to xCreateTokenizer()).
12582 **   The second and third arguments are an array of nul-terminated strings
12583 **   containing the tokenizer arguments, if any, specified following the
12584 **   tokenizer name as part of the CREATE VIRTUAL TABLE statement used
12585 **   to create the FTS5 table.
12586 **
12587 **   The final argument is an output variable. If successful, (*ppOut)
12588 **   should be set to point to the new tokenizer handle and SQLITE_OK
12589 **   returned. If an error occurs, some value other than SQLITE_OK should
12590 **   be returned. In this case, fts5 assumes that the final value of *ppOut
12591 **   is undefined.
12592 **
12593 ** xDelete:
12594 **   This function is invoked to delete a tokenizer handle previously
12595 **   allocated using xCreate(). Fts5 guarantees that this function will
12596 **   be invoked exactly once for each successful call to xCreate().
12597 **
12598 ** xTokenize:
12599 **   This function is expected to tokenize the nText byte string indicated
12600 **   by argument pText. pText may or may not be nul-terminated. The first
12601 **   argument passed to this function is a pointer to an Fts5Tokenizer object
12602 **   returned by an earlier call to xCreate().
12603 **
12604 **   The second argument indicates the reason that FTS5 is requesting
12605 **   tokenization of the supplied text. This is always one of the following
12606 **   four values:
12607 **
12608 **   <ul><li> <b>FTS5_TOKENIZE_DOCUMENT</b> - A document is being inserted into
12609 **            or removed from the FTS table. The tokenizer is being invoked to
12610 **            determine the set of tokens to add to (or delete from) the
12611 **            FTS index.
12612 **
12613 **       <li> <b>FTS5_TOKENIZE_QUERY</b> - A MATCH query is being executed
12614 **            against the FTS index. The tokenizer is being called to tokenize
12615 **            a bareword or quoted string specified as part of the query.
12616 **
12617 **       <li> <b>(FTS5_TOKENIZE_QUERY | FTS5_TOKENIZE_PREFIX)</b> - Same as
12618 **            FTS5_TOKENIZE_QUERY, except that the bareword or quoted string is
12619 **            followed by a "*" character, indicating that the last token
12620 **            returned by the tokenizer will be treated as a token prefix.
12621 **
12622 **       <li> <b>FTS5_TOKENIZE_AUX</b> - The tokenizer is being invoked to
12623 **            satisfy an fts5_api.xTokenize() request made by an auxiliary
12624 **            function. Or an fts5_api.xColumnSize() request made by the same
12625 **            on a columnsize=0 database.
12626 **   </ul>
12627 **
12628 **   For each token in the input string, the supplied callback xToken() must
12629 **   be invoked. The first argument to it should be a copy of the pointer
12630 **   passed as the second argument to xTokenize(). The third and fourth
12631 **   arguments are a pointer to a buffer containing the token text, and the
12632 **   size of the token in bytes. The 4th and 5th arguments are the byte offsets
12633 **   of the first byte of and first byte immediately following the text from
12634 **   which the token is derived within the input.
12635 **
12636 **   The second argument passed to the xToken() callback ("tflags") should
12637 **   normally be set to 0. The exception is if the tokenizer supports
12638 **   synonyms. In this case see the discussion below for details.
12639 **
12640 **   FTS5 assumes the xToken() callback is invoked for each token in the
12641 **   order that they occur within the input text.
12642 **
12643 **   If an xToken() callback returns any value other than SQLITE_OK, then
12644 **   the tokenization should be abandoned and the xTokenize() method should
12645 **   immediately return a copy of the xToken() return value. Or, if the
12646 **   input buffer is exhausted, xTokenize() should return SQLITE_OK. Finally,
12647 **   if an error occurs with the xTokenize() implementation itself, it
12648 **   may abandon the tokenization and return any error code other than
12649 **   SQLITE_OK or SQLITE_DONE.
12650 **
12651 ** SYNONYM SUPPORT
12652 **
12653 **   Custom tokenizers may also support synonyms. Consider a case in which a
12654 **   user wishes to query for a phrase such as "first place". Using the
12655 **   built-in tokenizers, the FTS5 query 'first + place' will match instances
12656 **   of "first place" within the document set, but not alternative forms
12657 **   such as "1st place". In some applications, it would be better to match
12658 **   all instances of "first place" or "1st place" regardless of which form
12659 **   the user specified in the MATCH query text.
12660 **
12661 **   There are several ways to approach this in FTS5:
12662 **
12663 **   <ol><li> By mapping all synonyms to a single token. In this case, using
12664 **            the above example, this means that the tokenizer returns the
12665 **            same token for inputs "first" and "1st". Say that token is in
12666 **            fact "first", so that when the user inserts the document "I won
12667 **            1st place" entries are added to the index for tokens "i", "won",
12668 **            "first" and "place". If the user then queries for '1st + place',
12669 **            the tokenizer substitutes "first" for "1st" and the query works
12670 **            as expected.
12671 **
12672 **       <li> By querying the index for all synonyms of each query term
12673 **            separately. In this case, when tokenizing query text, the
12674 **            tokenizer may provide multiple synonyms for a single term
12675 **            within the document. FTS5 then queries the index for each
12676 **            synonym individually. For example, faced with the query:
12677 **
12678 **   <codeblock>
12679 **     ... MATCH 'first place'</codeblock>
12680 **
12681 **            the tokenizer offers both "1st" and "first" as synonyms for the
12682 **            first token in the MATCH query and FTS5 effectively runs a query
12683 **            similar to:
12684 **
12685 **   <codeblock>
12686 **     ... MATCH '(first OR 1st) place'</codeblock>
12687 **
12688 **            except that, for the purposes of auxiliary functions, the query
12689 **            still appears to contain just two phrases - "(first OR 1st)"
12690 **            being treated as a single phrase.
12691 **
12692 **       <li> By adding multiple synonyms for a single term to the FTS index.
12693 **            Using this method, when tokenizing document text, the tokenizer
12694 **            provides multiple synonyms for each token. So that when a
12695 **            document such as "I won first place" is tokenized, entries are
12696 **            added to the FTS index for "i", "won", "first", "1st" and
12697 **            "place".
12698 **
12699 **            This way, even if the tokenizer does not provide synonyms
12700 **            when tokenizing query text (it should not - to do so would be
12701 **            inefficient), it doesn't matter if the user queries for
12702 **            'first + place' or '1st + place', as there are entries in the
12703 **            FTS index corresponding to both forms of the first token.
12704 **   </ol>
12705 **
12706 **   Whether it is parsing document or query text, any call to xToken that
12707 **   specifies a <i>tflags</i> argument with the FTS5_TOKEN_COLOCATED bit
12708 **   is considered to supply a synonym for the previous token. For example,
12709 **   when parsing the document "I won first place", a tokenizer that supports
12710 **   synonyms would call xToken() 5 times, as follows:
12711 **
12712 **   <codeblock>
12713 **       xToken(pCtx, 0, "i",                      1,  0,  1);
12714 **       xToken(pCtx, 0, "won",                    3,  2,  5);
12715 **       xToken(pCtx, 0, "first",                  5,  6, 11);
12716 **       xToken(pCtx, FTS5_TOKEN_COLOCATED, "1st", 3,  6, 11);
12717 **       xToken(pCtx, 0, "place",                  5, 12, 17);
12718 **</codeblock>
12719 **
12720 **   It is an error to specify the FTS5_TOKEN_COLOCATED flag the first time
12721 **   xToken() is called. Multiple synonyms may be specified for a single token
12722 **   by making multiple calls to xToken(FTS5_TOKEN_COLOCATED) in sequence.
12723 **   There is no limit to the number of synonyms that may be provided for a
12724 **   single token.
12725 **
12726 **   In many cases, method (1) above is the best approach. It does not add
12727 **   extra data to the FTS index or require FTS5 to query for multiple terms,
12728 **   so it is efficient in terms of disk space and query speed. However, it
12729 **   does not support prefix queries very well. If, as suggested above, the
12730 **   token "first" is substituted for "1st" by the tokenizer, then the query:
12731 **
12732 **   <codeblock>
12733 **     ... MATCH '1s*'</codeblock>
12734 **
12735 **   will not match documents that contain the token "1st" (as the tokenizer
12736 **   will probably not map "1s" to any prefix of "first").
12737 **
12738 **   For full prefix support, method (3) may be preferred. In this case,
12739 **   because the index contains entries for both "first" and "1st", prefix
12740 **   queries such as 'fi*' or '1s*' will match correctly. However, because
12741 **   extra entries are added to the FTS index, this method uses more space
12742 **   within the database.
12743 **
12744 **   Method (2) offers a midpoint between (1) and (3). Using this method,
12745 **   a query such as '1s*' will match documents that contain the literal
12746 **   token "1st", but not "first" (assuming the tokenizer is not able to
12747 **   provide synonyms for prefixes). However, a non-prefix query like '1st'
12748 **   will match against "1st" and "first". This method does not require
12749 **   extra disk space, as no extra entries are added to the FTS index.
12750 **   On the other hand, it may require more CPU cycles to run MATCH queries,
12751 **   as separate queries of the FTS index are required for each synonym.
12752 **
12753 **   When using methods (2) or (3), it is important that the tokenizer only
12754 **   provide synonyms when tokenizing document text (method (2)) or query
12755 **   text (method (3)), not both. Doing so will not cause any errors, but is
12756 **   inefficient.
12757 */
12758 typedef struct Fts5Tokenizer Fts5Tokenizer;
12759 typedef struct fts5_tokenizer fts5_tokenizer;
12760 struct fts5_tokenizer {
12761   int (*xCreate)(void*, const char **azArg, int nArg, Fts5Tokenizer **ppOut);
12762   void (*xDelete)(Fts5Tokenizer*);
12763   int (*xTokenize)(Fts5Tokenizer*,
12764       void *pCtx,
12765       int flags,            /* Mask of FTS5_TOKENIZE_* flags */
12766       const char *pText, int nText,
12767       int (*xToken)(
12768         void *pCtx,         /* Copy of 2nd argument to xTokenize() */
12769         int tflags,         /* Mask of FTS5_TOKEN_* flags */
12770         const char *pToken, /* Pointer to buffer containing token */
12771         int nToken,         /* Size of token in bytes */
12772         int iStart,         /* Byte offset of token within input text */
12773         int iEnd            /* Byte offset of end of token within input text */
12774       )
12775   );
12776 };
12777 
12778 /* Flags that may be passed as the third argument to xTokenize() */
12779 #define FTS5_TOKENIZE_QUERY     0x0001
12780 #define FTS5_TOKENIZE_PREFIX    0x0002
12781 #define FTS5_TOKENIZE_DOCUMENT  0x0004
12782 #define FTS5_TOKENIZE_AUX       0x0008
12783 
12784 /* Flags that may be passed by the tokenizer implementation back to FTS5
12785 ** as the third argument to the supplied xToken callback. */
12786 #define FTS5_TOKEN_COLOCATED    0x0001      /* Same position as prev. token */
12787 
12788 /*
12789 ** END OF CUSTOM TOKENIZERS
12790 *************************************************************************/
12791 
12792 /*************************************************************************
12793 ** FTS5 EXTENSION REGISTRATION API
12794 */
12795 typedef struct fts5_api fts5_api;
12796 struct fts5_api {
12797   int iVersion;                   /* Currently always set to 2 */
12798 
12799   /* Create a new tokenizer */
12800   int (*xCreateTokenizer)(
12801     fts5_api *pApi,
12802     const char *zName,
12803     void *pContext,
12804     fts5_tokenizer *pTokenizer,
12805     void (*xDestroy)(void*)
12806   );
12807 
12808   /* Find an existing tokenizer */
12809   int (*xFindTokenizer)(
12810     fts5_api *pApi,
12811     const char *zName,
12812     void **ppContext,
12813     fts5_tokenizer *pTokenizer
12814   );
12815 
12816   /* Create a new auxiliary function */
12817   int (*xCreateFunction)(
12818     fts5_api *pApi,
12819     const char *zName,
12820     void *pContext,
12821     fts5_extension_function xFunction,
12822     void (*xDestroy)(void*)
12823   );
12824 };
12825 
12826 /*
12827 ** END OF REGISTRATION API
12828 *************************************************************************/
12829 
12830 #ifdef __cplusplus
12831 }  /* end of the 'extern "C"' block */
12832 #endif
12833 
12834 #endif /* _FTS5_H */
12835 
12836 /******** End of fts5.h *********/
12837