xref: /freebsd/contrib/sqlite3/sqlite3.h (revision 5ab1c5846ff41be24b1f6beb0317bf8258cd4409)
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 ** Provide the ability to override linkage features of the interface.
47 */
48 #ifndef SQLITE_EXTERN
49 # define SQLITE_EXTERN extern
50 #endif
51 #ifndef SQLITE_API
52 # define SQLITE_API
53 #endif
54 #ifndef SQLITE_CDECL
55 # define SQLITE_CDECL
56 #endif
57 #ifndef SQLITE_APICALL
58 # define SQLITE_APICALL
59 #endif
60 #ifndef SQLITE_STDCALL
61 # define SQLITE_STDCALL SQLITE_APICALL
62 #endif
63 #ifndef SQLITE_CALLBACK
64 # define SQLITE_CALLBACK
65 #endif
66 #ifndef SQLITE_SYSAPI
67 # define SQLITE_SYSAPI
68 #endif
69 
70 /*
71 ** These no-op macros are used in front of interfaces to mark those
72 ** interfaces as either deprecated or experimental.  New applications
73 ** should not use deprecated interfaces - they are supported for backwards
74 ** compatibility only.  Application writers should be aware that
75 ** experimental interfaces are subject to change in point releases.
76 **
77 ** These macros used to resolve to various kinds of compiler magic that
78 ** would generate warning messages when they were used.  But that
79 ** compiler magic ended up generating such a flurry of bug reports
80 ** that we have taken it all out and gone back to using simple
81 ** noop macros.
82 */
83 #define SQLITE_DEPRECATED
84 #define SQLITE_EXPERIMENTAL
85 
86 /*
87 ** Ensure these symbols were not defined by some previous header file.
88 */
89 #ifdef SQLITE_VERSION
90 # undef SQLITE_VERSION
91 #endif
92 #ifdef SQLITE_VERSION_NUMBER
93 # undef SQLITE_VERSION_NUMBER
94 #endif
95 
96 /*
97 ** CAPI3REF: Compile-Time Library Version Numbers
98 **
99 ** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header
100 ** evaluates to a string literal that is the SQLite version in the
101 ** format "X.Y.Z" where X is the major version number (always 3 for
102 ** SQLite3) and Y is the minor version number and Z is the release number.)^
103 ** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer
104 ** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same
105 ** numbers used in [SQLITE_VERSION].)^
106 ** The SQLITE_VERSION_NUMBER for any given release of SQLite will also
107 ** be larger than the release from which it is derived.  Either Y will
108 ** be held constant and Z will be incremented or else Y will be incremented
109 ** and Z will be reset to zero.
110 **
111 ** Since [version 3.6.18] ([dateof:3.6.18]),
112 ** SQLite source code has been stored in the
113 ** <a href="http://www.fossil-scm.org/">Fossil configuration management
114 ** system</a>.  ^The SQLITE_SOURCE_ID macro evaluates to
115 ** a string which identifies a particular check-in of SQLite
116 ** within its configuration management system.  ^The SQLITE_SOURCE_ID
117 ** string contains the date and time of the check-in (UTC) and a SHA1
118 ** or SHA3-256 hash of the entire source tree.  If the source code has
119 ** been edited in any way since it was last checked in, then the last
120 ** four hexadecimal digits of the hash may be modified.
121 **
122 ** See also: [sqlite3_libversion()],
123 ** [sqlite3_libversion_number()], [sqlite3_sourceid()],
124 ** [sqlite_version()] and [sqlite_source_id()].
125 */
126 #define SQLITE_VERSION        "3.30.1"
127 #define SQLITE_VERSION_NUMBER 3030001
128 #define SQLITE_SOURCE_ID      "2019-10-10 20:19:45 18db032d058f1436ce3dea84081f4ee5a0f2259ad97301d43c426bc7f3df1b0b"
129 
130 /*
131 ** CAPI3REF: Run-Time Library Version Numbers
132 ** KEYWORDS: sqlite3_version sqlite3_sourceid
133 **
134 ** These interfaces provide the same information as the [SQLITE_VERSION],
135 ** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros
136 ** but are associated with the library instead of the header file.  ^(Cautious
137 ** programmers might include assert() statements in their application to
138 ** verify that values returned by these interfaces match the macros in
139 ** the header, and thus ensure that the application is
140 ** compiled with matching library and header files.
141 **
142 ** <blockquote><pre>
143 ** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
144 ** assert( strncmp(sqlite3_sourceid(),SQLITE_SOURCE_ID,80)==0 );
145 ** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
146 ** </pre></blockquote>)^
147 **
148 ** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION]
149 ** macro.  ^The sqlite3_libversion() function returns a pointer to the
150 ** to the sqlite3_version[] string constant.  The sqlite3_libversion()
151 ** function is provided for use in DLLs since DLL users usually do not have
152 ** direct access to string constants within the DLL.  ^The
153 ** sqlite3_libversion_number() function returns an integer equal to
154 ** [SQLITE_VERSION_NUMBER].  ^(The sqlite3_sourceid() function returns
155 ** a pointer to a string constant whose value is the same as the
156 ** [SQLITE_SOURCE_ID] C preprocessor macro.  Except if SQLite is built
157 ** using an edited copy of [the amalgamation], then the last four characters
158 ** of the hash might be different from [SQLITE_SOURCE_ID].)^
159 **
160 ** See also: [sqlite_version()] and [sqlite_source_id()].
161 */
162 SQLITE_API SQLITE_EXTERN const char sqlite3_version[];
163 SQLITE_API const char *sqlite3_libversion(void);
164 SQLITE_API const char *sqlite3_sourceid(void);
165 SQLITE_API int sqlite3_libversion_number(void);
166 
167 /*
168 ** CAPI3REF: Run-Time Library Compilation Options Diagnostics
169 **
170 ** ^The sqlite3_compileoption_used() function returns 0 or 1
171 ** indicating whether the specified option was defined at
172 ** compile time.  ^The SQLITE_ prefix may be omitted from the
173 ** option name passed to sqlite3_compileoption_used().
174 **
175 ** ^The sqlite3_compileoption_get() function allows iterating
176 ** over the list of options that were defined at compile time by
177 ** returning the N-th compile time option string.  ^If N is out of range,
178 ** sqlite3_compileoption_get() returns a NULL pointer.  ^The SQLITE_
179 ** prefix is omitted from any strings returned by
180 ** sqlite3_compileoption_get().
181 **
182 ** ^Support for the diagnostic functions sqlite3_compileoption_used()
183 ** and sqlite3_compileoption_get() may be omitted by specifying the
184 ** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time.
185 **
186 ** See also: SQL functions [sqlite_compileoption_used()] and
187 ** [sqlite_compileoption_get()] and the [compile_options pragma].
188 */
189 #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
190 SQLITE_API int sqlite3_compileoption_used(const char *zOptName);
191 SQLITE_API const char *sqlite3_compileoption_get(int N);
192 #else
193 # define sqlite3_compileoption_used(X) 0
194 # define sqlite3_compileoption_get(X)  ((void*)0)
195 #endif
196 
197 /*
198 ** CAPI3REF: Test To See If The Library Is Threadsafe
199 **
200 ** ^The sqlite3_threadsafe() function returns zero if and only if
201 ** SQLite was compiled with mutexing code omitted due to the
202 ** [SQLITE_THREADSAFE] compile-time option being set to 0.
203 **
204 ** SQLite can be compiled with or without mutexes.  When
205 ** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
206 ** are enabled and SQLite is threadsafe.  When the
207 ** [SQLITE_THREADSAFE] macro is 0,
208 ** the mutexes are omitted.  Without the mutexes, it is not safe
209 ** to use SQLite concurrently from more than one thread.
210 **
211 ** Enabling mutexes incurs a measurable performance penalty.
212 ** So if speed is of utmost importance, it makes sense to disable
213 ** the mutexes.  But for maximum safety, mutexes should be enabled.
214 ** ^The default behavior is for mutexes to be enabled.
215 **
216 ** This interface can be used by an application to make sure that the
217 ** version of SQLite that it is linking against was compiled with
218 ** the desired setting of the [SQLITE_THREADSAFE] macro.
219 **
220 ** This interface only reports on the compile-time mutex setting
221 ** of the [SQLITE_THREADSAFE] flag.  If SQLite is compiled with
222 ** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
223 ** can be fully or partially disabled using a call to [sqlite3_config()]
224 ** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD],
225 ** or [SQLITE_CONFIG_SERIALIZED].  ^(The return value of the
226 ** sqlite3_threadsafe() function shows only the compile-time setting of
227 ** thread safety, not any run-time changes to that setting made by
228 ** sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
229 ** is unchanged by calls to sqlite3_config().)^
230 **
231 ** See the [threading mode] documentation for additional information.
232 */
233 SQLITE_API int sqlite3_threadsafe(void);
234 
235 /*
236 ** CAPI3REF: Database Connection Handle
237 ** KEYWORDS: {database connection} {database connections}
238 **
239 ** Each open SQLite database is represented by a pointer to an instance of
240 ** the opaque structure named "sqlite3".  It is useful to think of an sqlite3
241 ** pointer as an object.  The [sqlite3_open()], [sqlite3_open16()], and
242 ** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
243 ** and [sqlite3_close_v2()] are its destructors.  There are many other
244 ** interfaces (such as
245 ** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
246 ** [sqlite3_busy_timeout()] to name but three) that are methods on an
247 ** sqlite3 object.
248 */
249 typedef struct sqlite3 sqlite3;
250 
251 /*
252 ** CAPI3REF: 64-Bit Integer Types
253 ** KEYWORDS: sqlite_int64 sqlite_uint64
254 **
255 ** Because there is no cross-platform way to specify 64-bit integer types
256 ** SQLite includes typedefs for 64-bit signed and unsigned integers.
257 **
258 ** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
259 ** The sqlite_int64 and sqlite_uint64 types are supported for backwards
260 ** compatibility only.
261 **
262 ** ^The sqlite3_int64 and sqlite_int64 types can store integer values
263 ** between -9223372036854775808 and +9223372036854775807 inclusive.  ^The
264 ** sqlite3_uint64 and sqlite_uint64 types can store integer values
265 ** between 0 and +18446744073709551615 inclusive.
266 */
267 #ifdef SQLITE_INT64_TYPE
268   typedef SQLITE_INT64_TYPE sqlite_int64;
269 # ifdef SQLITE_UINT64_TYPE
270     typedef SQLITE_UINT64_TYPE sqlite_uint64;
271 # else
272     typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
273 # endif
274 #elif defined(_MSC_VER) || defined(__BORLANDC__)
275   typedef __int64 sqlite_int64;
276   typedef unsigned __int64 sqlite_uint64;
277 #else
278   typedef long long int sqlite_int64;
279   typedef unsigned long long int sqlite_uint64;
280 #endif
281 typedef sqlite_int64 sqlite3_int64;
282 typedef sqlite_uint64 sqlite3_uint64;
283 
284 /*
285 ** If compiling for a processor that lacks floating point support,
286 ** substitute integer for floating-point.
287 */
288 #ifdef SQLITE_OMIT_FLOATING_POINT
289 # define double sqlite3_int64
290 #endif
291 
292 /*
293 ** CAPI3REF: Closing A Database Connection
294 ** DESTRUCTOR: sqlite3
295 **
296 ** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors
297 ** for the [sqlite3] object.
298 ** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if
299 ** the [sqlite3] object is successfully destroyed and all associated
300 ** resources are deallocated.
301 **
302 ** ^If the database connection is associated with unfinalized prepared
303 ** statements or unfinished sqlite3_backup objects then sqlite3_close()
304 ** will leave the database connection open and return [SQLITE_BUSY].
305 ** ^If sqlite3_close_v2() is called with unfinalized prepared statements
306 ** and/or unfinished sqlite3_backups, then the database connection becomes
307 ** an unusable "zombie" which will automatically be deallocated when the
308 ** last prepared statement is finalized or the last sqlite3_backup is
309 ** finished.  The sqlite3_close_v2() interface is intended for use with
310 ** host languages that are garbage collected, and where the order in which
311 ** destructors are called is arbitrary.
312 **
313 ** Applications should [sqlite3_finalize | finalize] all [prepared statements],
314 ** [sqlite3_blob_close | close] all [BLOB handles], and
315 ** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated
316 ** with the [sqlite3] object prior to attempting to close the object.  ^If
317 ** sqlite3_close_v2() is called on a [database connection] that still has
318 ** outstanding [prepared statements], [BLOB handles], and/or
319 ** [sqlite3_backup] objects then it returns [SQLITE_OK] and the deallocation
320 ** of resources is deferred until all [prepared statements], [BLOB handles],
321 ** and [sqlite3_backup] objects are also destroyed.
322 **
323 ** ^If an [sqlite3] object is destroyed while a transaction is open,
324 ** the transaction is automatically rolled back.
325 **
326 ** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)]
327 ** must be either a NULL
328 ** pointer or an [sqlite3] object pointer obtained
329 ** from [sqlite3_open()], [sqlite3_open16()], or
330 ** [sqlite3_open_v2()], and not previously closed.
331 ** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer
332 ** argument is a harmless no-op.
333 */
334 SQLITE_API int sqlite3_close(sqlite3*);
335 SQLITE_API int sqlite3_close_v2(sqlite3*);
336 
337 /*
338 ** The type for a callback function.
339 ** This is legacy and deprecated.  It is included for historical
340 ** compatibility and is not documented.
341 */
342 typedef int (*sqlite3_callback)(void*,int,char**, char**);
343 
344 /*
345 ** CAPI3REF: One-Step Query Execution Interface
346 ** METHOD: sqlite3
347 **
348 ** The sqlite3_exec() interface is a convenience wrapper around
349 ** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
350 ** that allows an application to run multiple statements of SQL
351 ** without having to use a lot of C code.
352 **
353 ** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
354 ** semicolon-separate SQL statements passed into its 2nd argument,
355 ** in the context of the [database connection] passed in as its 1st
356 ** argument.  ^If the callback function of the 3rd argument to
357 ** sqlite3_exec() is not NULL, then it is invoked for each result row
358 ** coming out of the evaluated SQL statements.  ^The 4th argument to
359 ** sqlite3_exec() is relayed through to the 1st argument of each
360 ** callback invocation.  ^If the callback pointer to sqlite3_exec()
361 ** is NULL, then no callback is ever invoked and result rows are
362 ** ignored.
363 **
364 ** ^If an error occurs while evaluating the SQL statements passed into
365 ** sqlite3_exec(), then execution of the current statement stops and
366 ** subsequent statements are skipped.  ^If the 5th parameter to sqlite3_exec()
367 ** is not NULL then any error message is written into memory obtained
368 ** from [sqlite3_malloc()] and passed back through the 5th parameter.
369 ** To avoid memory leaks, the application should invoke [sqlite3_free()]
370 ** on error message strings returned through the 5th parameter of
371 ** sqlite3_exec() after the error message string is no longer needed.
372 ** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
373 ** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
374 ** NULL before returning.
375 **
376 ** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
377 ** routine returns SQLITE_ABORT without invoking the callback again and
378 ** without running any subsequent SQL statements.
379 **
380 ** ^The 2nd argument to the sqlite3_exec() callback function is the
381 ** number of columns in the result.  ^The 3rd argument to the sqlite3_exec()
382 ** callback is an array of pointers to strings obtained as if from
383 ** [sqlite3_column_text()], one for each column.  ^If an element of a
384 ** result row is NULL then the corresponding string pointer for the
385 ** sqlite3_exec() callback is a NULL pointer.  ^The 4th argument to the
386 ** sqlite3_exec() callback is an array of pointers to strings where each
387 ** entry represents the name of corresponding result column as obtained
388 ** from [sqlite3_column_name()].
389 **
390 ** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
391 ** to an empty string, or a pointer that contains only whitespace and/or
392 ** SQL comments, then no SQL statements are evaluated and the database
393 ** is not changed.
394 **
395 ** Restrictions:
396 **
397 ** <ul>
398 ** <li> The application must ensure that the 1st parameter to sqlite3_exec()
399 **      is a valid and open [database connection].
400 ** <li> The application must not close the [database connection] specified by
401 **      the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
402 ** <li> The application must not modify the SQL statement text passed into
403 **      the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
404 ** </ul>
405 */
406 SQLITE_API int sqlite3_exec(
407   sqlite3*,                                  /* An open database */
408   const char *sql,                           /* SQL to be evaluated */
409   int (*callback)(void*,int,char**,char**),  /* Callback function */
410   void *,                                    /* 1st argument to callback */
411   char **errmsg                              /* Error msg written here */
412 );
413 
414 /*
415 ** CAPI3REF: Result Codes
416 ** KEYWORDS: {result code definitions}
417 **
418 ** Many SQLite functions return an integer result code from the set shown
419 ** here in order to indicate success or failure.
420 **
421 ** New error codes may be added in future versions of SQLite.
422 **
423 ** See also: [extended result code definitions]
424 */
425 #define SQLITE_OK           0   /* Successful result */
426 /* beginning-of-error-codes */
427 #define SQLITE_ERROR        1   /* Generic error */
428 #define SQLITE_INTERNAL     2   /* Internal logic error in SQLite */
429 #define SQLITE_PERM         3   /* Access permission denied */
430 #define SQLITE_ABORT        4   /* Callback routine requested an abort */
431 #define SQLITE_BUSY         5   /* The database file is locked */
432 #define SQLITE_LOCKED       6   /* A table in the database is locked */
433 #define SQLITE_NOMEM        7   /* A malloc() failed */
434 #define SQLITE_READONLY     8   /* Attempt to write a readonly database */
435 #define SQLITE_INTERRUPT    9   /* Operation terminated by sqlite3_interrupt()*/
436 #define SQLITE_IOERR       10   /* Some kind of disk I/O error occurred */
437 #define SQLITE_CORRUPT     11   /* The database disk image is malformed */
438 #define SQLITE_NOTFOUND    12   /* Unknown opcode in sqlite3_file_control() */
439 #define SQLITE_FULL        13   /* Insertion failed because database is full */
440 #define SQLITE_CANTOPEN    14   /* Unable to open the database file */
441 #define SQLITE_PROTOCOL    15   /* Database lock protocol error */
442 #define SQLITE_EMPTY       16   /* Internal use only */
443 #define SQLITE_SCHEMA      17   /* The database schema changed */
444 #define SQLITE_TOOBIG      18   /* String or BLOB exceeds size limit */
445 #define SQLITE_CONSTRAINT  19   /* Abort due to constraint violation */
446 #define SQLITE_MISMATCH    20   /* Data type mismatch */
447 #define SQLITE_MISUSE      21   /* Library used incorrectly */
448 #define SQLITE_NOLFS       22   /* Uses OS features not supported on host */
449 #define SQLITE_AUTH        23   /* Authorization denied */
450 #define SQLITE_FORMAT      24   /* Not used */
451 #define SQLITE_RANGE       25   /* 2nd parameter to sqlite3_bind out of range */
452 #define SQLITE_NOTADB      26   /* File opened that is not a database file */
453 #define SQLITE_NOTICE      27   /* Notifications from sqlite3_log() */
454 #define SQLITE_WARNING     28   /* Warnings from sqlite3_log() */
455 #define SQLITE_ROW         100  /* sqlite3_step() has another row ready */
456 #define SQLITE_DONE        101  /* sqlite3_step() has finished executing */
457 /* end-of-error-codes */
458 
459 /*
460 ** CAPI3REF: Extended Result Codes
461 ** KEYWORDS: {extended result code definitions}
462 **
463 ** In its default configuration, SQLite API routines return one of 30 integer
464 ** [result codes].  However, experience has shown that many of
465 ** these result codes are too coarse-grained.  They do not provide as
466 ** much information about problems as programmers might like.  In an effort to
467 ** address this, newer versions of SQLite (version 3.3.8 [dateof:3.3.8]
468 ** and later) include
469 ** support for additional result codes that provide more detailed information
470 ** about errors. These [extended result codes] are enabled or disabled
471 ** on a per database connection basis using the
472 ** [sqlite3_extended_result_codes()] API.  Or, the extended code for
473 ** the most recent error can be obtained using
474 ** [sqlite3_extended_errcode()].
475 */
476 #define SQLITE_ERROR_MISSING_COLLSEQ   (SQLITE_ERROR | (1<<8))
477 #define SQLITE_ERROR_RETRY             (SQLITE_ERROR | (2<<8))
478 #define SQLITE_ERROR_SNAPSHOT          (SQLITE_ERROR | (3<<8))
479 #define SQLITE_IOERR_READ              (SQLITE_IOERR | (1<<8))
480 #define SQLITE_IOERR_SHORT_READ        (SQLITE_IOERR | (2<<8))
481 #define SQLITE_IOERR_WRITE             (SQLITE_IOERR | (3<<8))
482 #define SQLITE_IOERR_FSYNC             (SQLITE_IOERR | (4<<8))
483 #define SQLITE_IOERR_DIR_FSYNC         (SQLITE_IOERR | (5<<8))
484 #define SQLITE_IOERR_TRUNCATE          (SQLITE_IOERR | (6<<8))
485 #define SQLITE_IOERR_FSTAT             (SQLITE_IOERR | (7<<8))
486 #define SQLITE_IOERR_UNLOCK            (SQLITE_IOERR | (8<<8))
487 #define SQLITE_IOERR_RDLOCK            (SQLITE_IOERR | (9<<8))
488 #define SQLITE_IOERR_DELETE            (SQLITE_IOERR | (10<<8))
489 #define SQLITE_IOERR_BLOCKED           (SQLITE_IOERR | (11<<8))
490 #define SQLITE_IOERR_NOMEM             (SQLITE_IOERR | (12<<8))
491 #define SQLITE_IOERR_ACCESS            (SQLITE_IOERR | (13<<8))
492 #define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
493 #define SQLITE_IOERR_LOCK              (SQLITE_IOERR | (15<<8))
494 #define SQLITE_IOERR_CLOSE             (SQLITE_IOERR | (16<<8))
495 #define SQLITE_IOERR_DIR_CLOSE         (SQLITE_IOERR | (17<<8))
496 #define SQLITE_IOERR_SHMOPEN           (SQLITE_IOERR | (18<<8))
497 #define SQLITE_IOERR_SHMSIZE           (SQLITE_IOERR | (19<<8))
498 #define SQLITE_IOERR_SHMLOCK           (SQLITE_IOERR | (20<<8))
499 #define SQLITE_IOERR_SHMMAP            (SQLITE_IOERR | (21<<8))
500 #define SQLITE_IOERR_SEEK              (SQLITE_IOERR | (22<<8))
501 #define SQLITE_IOERR_DELETE_NOENT      (SQLITE_IOERR | (23<<8))
502 #define SQLITE_IOERR_MMAP              (SQLITE_IOERR | (24<<8))
503 #define SQLITE_IOERR_GETTEMPPATH       (SQLITE_IOERR | (25<<8))
504 #define SQLITE_IOERR_CONVPATH          (SQLITE_IOERR | (26<<8))
505 #define SQLITE_IOERR_VNODE             (SQLITE_IOERR | (27<<8))
506 #define SQLITE_IOERR_AUTH              (SQLITE_IOERR | (28<<8))
507 #define SQLITE_IOERR_BEGIN_ATOMIC      (SQLITE_IOERR | (29<<8))
508 #define SQLITE_IOERR_COMMIT_ATOMIC     (SQLITE_IOERR | (30<<8))
509 #define SQLITE_IOERR_ROLLBACK_ATOMIC   (SQLITE_IOERR | (31<<8))
510 #define SQLITE_LOCKED_SHAREDCACHE      (SQLITE_LOCKED |  (1<<8))
511 #define SQLITE_LOCKED_VTAB             (SQLITE_LOCKED |  (2<<8))
512 #define SQLITE_BUSY_RECOVERY           (SQLITE_BUSY   |  (1<<8))
513 #define SQLITE_BUSY_SNAPSHOT           (SQLITE_BUSY   |  (2<<8))
514 #define SQLITE_CANTOPEN_NOTEMPDIR      (SQLITE_CANTOPEN | (1<<8))
515 #define SQLITE_CANTOPEN_ISDIR          (SQLITE_CANTOPEN | (2<<8))
516 #define SQLITE_CANTOPEN_FULLPATH       (SQLITE_CANTOPEN | (3<<8))
517 #define SQLITE_CANTOPEN_CONVPATH       (SQLITE_CANTOPEN | (4<<8))
518 #define SQLITE_CANTOPEN_DIRTYWAL       (SQLITE_CANTOPEN | (5<<8)) /* Not Used */
519 #define SQLITE_CORRUPT_VTAB            (SQLITE_CORRUPT | (1<<8))
520 #define SQLITE_CORRUPT_SEQUENCE        (SQLITE_CORRUPT | (2<<8))
521 #define SQLITE_READONLY_RECOVERY       (SQLITE_READONLY | (1<<8))
522 #define SQLITE_READONLY_CANTLOCK       (SQLITE_READONLY | (2<<8))
523 #define SQLITE_READONLY_ROLLBACK       (SQLITE_READONLY | (3<<8))
524 #define SQLITE_READONLY_DBMOVED        (SQLITE_READONLY | (4<<8))
525 #define SQLITE_READONLY_CANTINIT       (SQLITE_READONLY | (5<<8))
526 #define SQLITE_READONLY_DIRECTORY      (SQLITE_READONLY | (6<<8))
527 #define SQLITE_ABORT_ROLLBACK          (SQLITE_ABORT | (2<<8))
528 #define SQLITE_CONSTRAINT_CHECK        (SQLITE_CONSTRAINT | (1<<8))
529 #define SQLITE_CONSTRAINT_COMMITHOOK   (SQLITE_CONSTRAINT | (2<<8))
530 #define SQLITE_CONSTRAINT_FOREIGNKEY   (SQLITE_CONSTRAINT | (3<<8))
531 #define SQLITE_CONSTRAINT_FUNCTION     (SQLITE_CONSTRAINT | (4<<8))
532 #define SQLITE_CONSTRAINT_NOTNULL      (SQLITE_CONSTRAINT | (5<<8))
533 #define SQLITE_CONSTRAINT_PRIMARYKEY   (SQLITE_CONSTRAINT | (6<<8))
534 #define SQLITE_CONSTRAINT_TRIGGER      (SQLITE_CONSTRAINT | (7<<8))
535 #define SQLITE_CONSTRAINT_UNIQUE       (SQLITE_CONSTRAINT | (8<<8))
536 #define SQLITE_CONSTRAINT_VTAB         (SQLITE_CONSTRAINT | (9<<8))
537 #define SQLITE_CONSTRAINT_ROWID        (SQLITE_CONSTRAINT |(10<<8))
538 #define SQLITE_NOTICE_RECOVER_WAL      (SQLITE_NOTICE | (1<<8))
539 #define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8))
540 #define SQLITE_WARNING_AUTOINDEX       (SQLITE_WARNING | (1<<8))
541 #define SQLITE_AUTH_USER               (SQLITE_AUTH | (1<<8))
542 #define SQLITE_OK_LOAD_PERMANENTLY     (SQLITE_OK | (1<<8))
543 
544 /*
545 ** CAPI3REF: Flags For File Open Operations
546 **
547 ** These bit values are intended for use in the
548 ** 3rd parameter to the [sqlite3_open_v2()] interface and
549 ** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
550 */
551 #define SQLITE_OPEN_READONLY         0x00000001  /* Ok for sqlite3_open_v2() */
552 #define SQLITE_OPEN_READWRITE        0x00000002  /* Ok for sqlite3_open_v2() */
553 #define SQLITE_OPEN_CREATE           0x00000004  /* Ok for sqlite3_open_v2() */
554 #define SQLITE_OPEN_DELETEONCLOSE    0x00000008  /* VFS only */
555 #define SQLITE_OPEN_EXCLUSIVE        0x00000010  /* VFS only */
556 #define SQLITE_OPEN_AUTOPROXY        0x00000020  /* VFS only */
557 #define SQLITE_OPEN_URI              0x00000040  /* Ok for sqlite3_open_v2() */
558 #define SQLITE_OPEN_MEMORY           0x00000080  /* Ok for sqlite3_open_v2() */
559 #define SQLITE_OPEN_MAIN_DB          0x00000100  /* VFS only */
560 #define SQLITE_OPEN_TEMP_DB          0x00000200  /* VFS only */
561 #define SQLITE_OPEN_TRANSIENT_DB     0x00000400  /* VFS only */
562 #define SQLITE_OPEN_MAIN_JOURNAL     0x00000800  /* VFS only */
563 #define SQLITE_OPEN_TEMP_JOURNAL     0x00001000  /* VFS only */
564 #define SQLITE_OPEN_SUBJOURNAL       0x00002000  /* VFS only */
565 #define SQLITE_OPEN_MASTER_JOURNAL   0x00004000  /* VFS only */
566 #define SQLITE_OPEN_NOMUTEX          0x00008000  /* Ok for sqlite3_open_v2() */
567 #define SQLITE_OPEN_FULLMUTEX        0x00010000  /* Ok for sqlite3_open_v2() */
568 #define SQLITE_OPEN_SHAREDCACHE      0x00020000  /* Ok for sqlite3_open_v2() */
569 #define SQLITE_OPEN_PRIVATECACHE     0x00040000  /* Ok for sqlite3_open_v2() */
570 #define SQLITE_OPEN_WAL              0x00080000  /* VFS only */
571 
572 /* Reserved:                         0x00F00000 */
573 
574 /*
575 ** CAPI3REF: Device Characteristics
576 **
577 ** The xDeviceCharacteristics method of the [sqlite3_io_methods]
578 ** object returns an integer which is a vector of these
579 ** bit values expressing I/O characteristics of the mass storage
580 ** device that holds the file that the [sqlite3_io_methods]
581 ** refers to.
582 **
583 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
584 ** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
585 ** mean that writes of blocks that are nnn bytes in size and
586 ** are aligned to an address which is an integer multiple of
587 ** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
588 ** that when data is appended to a file, the data is appended
589 ** first then the size of the file is extended, never the other
590 ** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
591 ** information is written to disk in the same order as calls
592 ** to xWrite().  The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
593 ** after reboot following a crash or power loss, the only bytes in a
594 ** file that were written at the application level might have changed
595 ** and that adjacent bytes, even bytes within the same sector are
596 ** guaranteed to be unchanged.  The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN
597 ** flag indicates that a file cannot be deleted when open.  The
598 ** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on
599 ** read-only media and cannot be changed even by processes with
600 ** elevated privileges.
601 **
602 ** The SQLITE_IOCAP_BATCH_ATOMIC property means that the underlying
603 ** filesystem supports doing multiple write operations atomically when those
604 ** write operations are bracketed by [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] and
605 ** [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE].
606 */
607 #define SQLITE_IOCAP_ATOMIC                 0x00000001
608 #define SQLITE_IOCAP_ATOMIC512              0x00000002
609 #define SQLITE_IOCAP_ATOMIC1K               0x00000004
610 #define SQLITE_IOCAP_ATOMIC2K               0x00000008
611 #define SQLITE_IOCAP_ATOMIC4K               0x00000010
612 #define SQLITE_IOCAP_ATOMIC8K               0x00000020
613 #define SQLITE_IOCAP_ATOMIC16K              0x00000040
614 #define SQLITE_IOCAP_ATOMIC32K              0x00000080
615 #define SQLITE_IOCAP_ATOMIC64K              0x00000100
616 #define SQLITE_IOCAP_SAFE_APPEND            0x00000200
617 #define SQLITE_IOCAP_SEQUENTIAL             0x00000400
618 #define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN  0x00000800
619 #define SQLITE_IOCAP_POWERSAFE_OVERWRITE    0x00001000
620 #define SQLITE_IOCAP_IMMUTABLE              0x00002000
621 #define SQLITE_IOCAP_BATCH_ATOMIC           0x00004000
622 
623 /*
624 ** CAPI3REF: File Locking Levels
625 **
626 ** SQLite uses one of these integer values as the second
627 ** argument to calls it makes to the xLock() and xUnlock() methods
628 ** of an [sqlite3_io_methods] object.
629 */
630 #define SQLITE_LOCK_NONE          0
631 #define SQLITE_LOCK_SHARED        1
632 #define SQLITE_LOCK_RESERVED      2
633 #define SQLITE_LOCK_PENDING       3
634 #define SQLITE_LOCK_EXCLUSIVE     4
635 
636 /*
637 ** CAPI3REF: Synchronization Type Flags
638 **
639 ** When SQLite invokes the xSync() method of an
640 ** [sqlite3_io_methods] object it uses a combination of
641 ** these integer values as the second argument.
642 **
643 ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
644 ** sync operation only needs to flush data to mass storage.  Inode
645 ** information need not be flushed. If the lower four bits of the flag
646 ** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
647 ** If the lower four bits equal SQLITE_SYNC_FULL, that means
648 ** to use Mac OS X style fullsync instead of fsync().
649 **
650 ** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
651 ** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
652 ** settings.  The [synchronous pragma] determines when calls to the
653 ** xSync VFS method occur and applies uniformly across all platforms.
654 ** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
655 ** energetic or rigorous or forceful the sync operations are and
656 ** only make a difference on Mac OSX for the default SQLite code.
657 ** (Third-party VFS implementations might also make the distinction
658 ** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
659 ** operating systems natively supported by SQLite, only Mac OSX
660 ** cares about the difference.)
661 */
662 #define SQLITE_SYNC_NORMAL        0x00002
663 #define SQLITE_SYNC_FULL          0x00003
664 #define SQLITE_SYNC_DATAONLY      0x00010
665 
666 /*
667 ** CAPI3REF: OS Interface Open File Handle
668 **
669 ** An [sqlite3_file] object represents an open file in the
670 ** [sqlite3_vfs | OS interface layer].  Individual OS interface
671 ** implementations will
672 ** want to subclass this object by appending additional fields
673 ** for their own use.  The pMethods entry is a pointer to an
674 ** [sqlite3_io_methods] object that defines methods for performing
675 ** I/O operations on the open file.
676 */
677 typedef struct sqlite3_file sqlite3_file;
678 struct sqlite3_file {
679   const struct sqlite3_io_methods *pMethods;  /* Methods for an open file */
680 };
681 
682 /*
683 ** CAPI3REF: OS Interface File Virtual Methods Object
684 **
685 ** Every file opened by the [sqlite3_vfs.xOpen] method populates an
686 ** [sqlite3_file] object (or, more commonly, a subclass of the
687 ** [sqlite3_file] object) with a pointer to an instance of this object.
688 ** This object defines the methods used to perform various operations
689 ** against the open file represented by the [sqlite3_file] object.
690 **
691 ** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element
692 ** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
693 ** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed.  The
694 ** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
695 ** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
696 ** to NULL.
697 **
698 ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
699 ** [SQLITE_SYNC_FULL].  The first choice is the normal fsync().
700 ** The second choice is a Mac OS X style fullsync.  The [SQLITE_SYNC_DATAONLY]
701 ** flag may be ORed in to indicate that only the data of the file
702 ** and not its inode needs to be synced.
703 **
704 ** The integer values to xLock() and xUnlock() are one of
705 ** <ul>
706 ** <li> [SQLITE_LOCK_NONE],
707 ** <li> [SQLITE_LOCK_SHARED],
708 ** <li> [SQLITE_LOCK_RESERVED],
709 ** <li> [SQLITE_LOCK_PENDING], or
710 ** <li> [SQLITE_LOCK_EXCLUSIVE].
711 ** </ul>
712 ** xLock() increases the lock. xUnlock() decreases the lock.
713 ** The xCheckReservedLock() method checks whether any database connection,
714 ** either in this process or in some other process, is holding a RESERVED,
715 ** PENDING, or EXCLUSIVE lock on the file.  It returns true
716 ** if such a lock exists and false otherwise.
717 **
718 ** The xFileControl() method is a generic interface that allows custom
719 ** VFS implementations to directly control an open file using the
720 ** [sqlite3_file_control()] interface.  The second "op" argument is an
721 ** integer opcode.  The third argument is a generic pointer intended to
722 ** point to a structure that may contain arguments or space in which to
723 ** write return values.  Potential uses for xFileControl() might be
724 ** functions to enable blocking locks with timeouts, to change the
725 ** locking strategy (for example to use dot-file locks), to inquire
726 ** about the status of a lock, or to break stale locks.  The SQLite
727 ** core reserves all opcodes less than 100 for its own use.
728 ** A [file control opcodes | list of opcodes] less than 100 is available.
729 ** Applications that define a custom xFileControl method should use opcodes
730 ** greater than 100 to avoid conflicts.  VFS implementations should
731 ** return [SQLITE_NOTFOUND] for file control opcodes that they do not
732 ** recognize.
733 **
734 ** The xSectorSize() method returns the sector size of the
735 ** device that underlies the file.  The sector size is the
736 ** minimum write that can be performed without disturbing
737 ** other bytes in the file.  The xDeviceCharacteristics()
738 ** method returns a bit vector describing behaviors of the
739 ** underlying device:
740 **
741 ** <ul>
742 ** <li> [SQLITE_IOCAP_ATOMIC]
743 ** <li> [SQLITE_IOCAP_ATOMIC512]
744 ** <li> [SQLITE_IOCAP_ATOMIC1K]
745 ** <li> [SQLITE_IOCAP_ATOMIC2K]
746 ** <li> [SQLITE_IOCAP_ATOMIC4K]
747 ** <li> [SQLITE_IOCAP_ATOMIC8K]
748 ** <li> [SQLITE_IOCAP_ATOMIC16K]
749 ** <li> [SQLITE_IOCAP_ATOMIC32K]
750 ** <li> [SQLITE_IOCAP_ATOMIC64K]
751 ** <li> [SQLITE_IOCAP_SAFE_APPEND]
752 ** <li> [SQLITE_IOCAP_SEQUENTIAL]
753 ** <li> [SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN]
754 ** <li> [SQLITE_IOCAP_POWERSAFE_OVERWRITE]
755 ** <li> [SQLITE_IOCAP_IMMUTABLE]
756 ** <li> [SQLITE_IOCAP_BATCH_ATOMIC]
757 ** </ul>
758 **
759 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
760 ** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
761 ** mean that writes of blocks that are nnn bytes in size and
762 ** are aligned to an address which is an integer multiple of
763 ** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
764 ** that when data is appended to a file, the data is appended
765 ** first then the size of the file is extended, never the other
766 ** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
767 ** information is written to disk in the same order as calls
768 ** to xWrite().
769 **
770 ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
771 ** in the unread portions of the buffer with zeros.  A VFS that
772 ** fails to zero-fill short reads might seem to work.  However,
773 ** failure to zero-fill short reads will eventually lead to
774 ** database corruption.
775 */
776 typedef struct sqlite3_io_methods sqlite3_io_methods;
777 struct sqlite3_io_methods {
778   int iVersion;
779   int (*xClose)(sqlite3_file*);
780   int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
781   int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
782   int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
783   int (*xSync)(sqlite3_file*, int flags);
784   int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
785   int (*xLock)(sqlite3_file*, int);
786   int (*xUnlock)(sqlite3_file*, int);
787   int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
788   int (*xFileControl)(sqlite3_file*, int op, void *pArg);
789   int (*xSectorSize)(sqlite3_file*);
790   int (*xDeviceCharacteristics)(sqlite3_file*);
791   /* Methods above are valid for version 1 */
792   int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
793   int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
794   void (*xShmBarrier)(sqlite3_file*);
795   int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
796   /* Methods above are valid for version 2 */
797   int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp);
798   int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p);
799   /* Methods above are valid for version 3 */
800   /* Additional methods may be added in future releases */
801 };
802 
803 /*
804 ** CAPI3REF: Standard File Control Opcodes
805 ** KEYWORDS: {file control opcodes} {file control opcode}
806 **
807 ** These integer constants are opcodes for the xFileControl method
808 ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
809 ** interface.
810 **
811 ** <ul>
812 ** <li>[[SQLITE_FCNTL_LOCKSTATE]]
813 ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging.  This
814 ** opcode causes the xFileControl method to write the current state of
815 ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
816 ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
817 ** into an integer that the pArg argument points to. This capability
818 ** is used during testing and is only available when the SQLITE_TEST
819 ** compile-time option is used.
820 **
821 ** <li>[[SQLITE_FCNTL_SIZE_HINT]]
822 ** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
823 ** layer a hint of how large the database file will grow to be during the
824 ** current transaction.  This hint is not guaranteed to be accurate but it
825 ** is often close.  The underlying VFS might choose to preallocate database
826 ** file space based on this hint in order to help writes to the database
827 ** file run faster.
828 **
829 ** <li>[[SQLITE_FCNTL_SIZE_LIMIT]]
830 ** The [SQLITE_FCNTL_SIZE_LIMIT] opcode is used by in-memory VFS that
831 ** implements [sqlite3_deserialize()] to set an upper bound on the size
832 ** of the in-memory database.  The argument is a pointer to a [sqlite3_int64].
833 ** If the integer pointed to is negative, then it is filled in with the
834 ** current limit.  Otherwise the limit is set to the larger of the value
835 ** of the integer pointed to and the current database size.  The integer
836 ** pointed to is set to the new limit.
837 **
838 ** <li>[[SQLITE_FCNTL_CHUNK_SIZE]]
839 ** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
840 ** extends and truncates the database file in chunks of a size specified
841 ** by the user. The fourth argument to [sqlite3_file_control()] should
842 ** point to an integer (type int) containing the new chunk-size to use
843 ** for the nominated database. Allocating database file space in large
844 ** chunks (say 1MB at a time), may reduce file-system fragmentation and
845 ** improve performance on some systems.
846 **
847 ** <li>[[SQLITE_FCNTL_FILE_POINTER]]
848 ** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
849 ** to the [sqlite3_file] object associated with a particular database
850 ** connection.  See also [SQLITE_FCNTL_JOURNAL_POINTER].
851 **
852 ** <li>[[SQLITE_FCNTL_JOURNAL_POINTER]]
853 ** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer
854 ** to the [sqlite3_file] object associated with the journal file (either
855 ** the [rollback journal] or the [write-ahead log]) for a particular database
856 ** connection.  See also [SQLITE_FCNTL_FILE_POINTER].
857 **
858 ** <li>[[SQLITE_FCNTL_SYNC_OMITTED]]
859 ** No longer in use.
860 **
861 ** <li>[[SQLITE_FCNTL_SYNC]]
862 ** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and
863 ** sent to the VFS immediately before the xSync method is invoked on a
864 ** database file descriptor. Or, if the xSync method is not invoked
865 ** because the user has configured SQLite with
866 ** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place
867 ** of the xSync method. In most cases, the pointer argument passed with
868 ** this file-control is NULL. However, if the database file is being synced
869 ** as part of a multi-database commit, the argument points to a nul-terminated
870 ** string containing the transactions master-journal file name. VFSes that
871 ** do not need this signal should silently ignore this opcode. Applications
872 ** should not call [sqlite3_file_control()] with this opcode as doing so may
873 ** disrupt the operation of the specialized VFSes that do require it.
874 **
875 ** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]]
876 ** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite
877 ** and sent to the VFS after a transaction has been committed immediately
878 ** but before the database is unlocked. VFSes that do not need this signal
879 ** should silently ignore this opcode. Applications should not call
880 ** [sqlite3_file_control()] with this opcode as doing so may disrupt the
881 ** operation of the specialized VFSes that do require it.
882 **
883 ** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]]
884 ** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
885 ** retry counts and intervals for certain disk I/O operations for the
886 ** windows [VFS] in order to provide robustness in the presence of
887 ** anti-virus programs.  By default, the windows VFS will retry file read,
888 ** file write, and file delete operations up to 10 times, with a delay
889 ** of 25 milliseconds before the first retry and with the delay increasing
890 ** by an additional 25 milliseconds with each subsequent retry.  This
891 ** opcode allows these two values (10 retries and 25 milliseconds of delay)
892 ** to be adjusted.  The values are changed for all database connections
893 ** within the same process.  The argument is a pointer to an array of two
894 ** integers where the first integer is the new retry count and the second
895 ** integer is the delay.  If either integer is negative, then the setting
896 ** is not changed but instead the prior value of that setting is written
897 ** into the array entry, allowing the current retry settings to be
898 ** interrogated.  The zDbName parameter is ignored.
899 **
900 ** <li>[[SQLITE_FCNTL_PERSIST_WAL]]
901 ** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
902 ** persistent [WAL | Write Ahead Log] setting.  By default, the auxiliary
903 ** write ahead log ([WAL file]) and shared memory
904 ** files used for transaction control
905 ** are automatically deleted when the latest connection to the database
906 ** closes.  Setting persistent WAL mode causes those files to persist after
907 ** close.  Persisting the files is useful when other processes that do not
908 ** have write permission on the directory containing the database file want
909 ** to read the database file, as the WAL and shared memory files must exist
910 ** in order for the database to be readable.  The fourth parameter to
911 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
912 ** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
913 ** WAL mode.  If the integer is -1, then it is overwritten with the current
914 ** WAL persistence setting.
915 **
916 ** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]]
917 ** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
918 ** persistent "powersafe-overwrite" or "PSOW" setting.  The PSOW setting
919 ** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
920 ** xDeviceCharacteristics methods. The fourth parameter to
921 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
922 ** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
923 ** mode.  If the integer is -1, then it is overwritten with the current
924 ** zero-damage mode setting.
925 **
926 ** <li>[[SQLITE_FCNTL_OVERWRITE]]
927 ** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
928 ** a write transaction to indicate that, unless it is rolled back for some
929 ** reason, the entire database file will be overwritten by the current
930 ** transaction. This is used by VACUUM operations.
931 **
932 ** <li>[[SQLITE_FCNTL_VFSNAME]]
933 ** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
934 ** all [VFSes] in the VFS stack.  The names are of all VFS shims and the
935 ** final bottom-level VFS are written into memory obtained from
936 ** [sqlite3_malloc()] and the result is stored in the char* variable
937 ** that the fourth parameter of [sqlite3_file_control()] points to.
938 ** The caller is responsible for freeing the memory when done.  As with
939 ** all file-control actions, there is no guarantee that this will actually
940 ** do anything.  Callers should initialize the char* variable to a NULL
941 ** pointer in case this file-control is not implemented.  This file-control
942 ** is intended for diagnostic use only.
943 **
944 ** <li>[[SQLITE_FCNTL_VFS_POINTER]]
945 ** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level
946 ** [VFSes] currently in use.  ^(The argument X in
947 ** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be
948 ** of type "[sqlite3_vfs] **".  This opcodes will set *X
949 ** to a pointer to the top-level VFS.)^
950 ** ^When there are multiple VFS shims in the stack, this opcode finds the
951 ** upper-most shim only.
952 **
953 ** <li>[[SQLITE_FCNTL_PRAGMA]]
954 ** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA]
955 ** file control is sent to the open [sqlite3_file] object corresponding
956 ** to the database file to which the pragma statement refers. ^The argument
957 ** to the [SQLITE_FCNTL_PRAGMA] file control is an array of
958 ** pointers to strings (char**) in which the second element of the array
959 ** is the name of the pragma and the third element is the argument to the
960 ** pragma or NULL if the pragma has no argument.  ^The handler for an
961 ** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element
962 ** of the char** argument point to a string obtained from [sqlite3_mprintf()]
963 ** or the equivalent and that string will become the result of the pragma or
964 ** the error message if the pragma fails. ^If the
965 ** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal
966 ** [PRAGMA] processing continues.  ^If the [SQLITE_FCNTL_PRAGMA]
967 ** file control returns [SQLITE_OK], then the parser assumes that the
968 ** VFS has handled the PRAGMA itself and the parser generates a no-op
969 ** prepared statement if result string is NULL, or that returns a copy
970 ** of the result string if the string is non-NULL.
971 ** ^If the [SQLITE_FCNTL_PRAGMA] file control returns
972 ** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means
973 ** that the VFS encountered an error while handling the [PRAGMA] and the
974 ** compilation of the PRAGMA fails with an error.  ^The [SQLITE_FCNTL_PRAGMA]
975 ** file control occurs at the beginning of pragma statement analysis and so
976 ** it is able to override built-in [PRAGMA] statements.
977 **
978 ** <li>[[SQLITE_FCNTL_BUSYHANDLER]]
979 ** ^The [SQLITE_FCNTL_BUSYHANDLER]
980 ** file-control may be invoked by SQLite on the database file handle
981 ** shortly after it is opened in order to provide a custom VFS with access
982 ** to the connections busy-handler callback. The argument is of type (void **)
983 ** - an array of two (void *) values. The first (void *) actually points
984 ** to a function of type (int (*)(void *)). In order to invoke the connections
985 ** busy-handler, this function should be invoked with the second (void *) in
986 ** the array as the only argument. If it returns non-zero, then the operation
987 ** should be retried. If it returns zero, the custom VFS should abandon the
988 ** current operation.
989 **
990 ** <li>[[SQLITE_FCNTL_TEMPFILENAME]]
991 ** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control
992 ** to have SQLite generate a
993 ** temporary filename using the same algorithm that is followed to generate
994 ** temporary filenames for TEMP tables and other internal uses.  The
995 ** argument should be a char** which will be filled with the filename
996 ** written into memory obtained from [sqlite3_malloc()].  The caller should
997 ** invoke [sqlite3_free()] on the result to avoid a memory leak.
998 **
999 ** <li>[[SQLITE_FCNTL_MMAP_SIZE]]
1000 ** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the
1001 ** maximum number of bytes that will be used for memory-mapped I/O.
1002 ** The argument is a pointer to a value of type sqlite3_int64 that
1003 ** is an advisory maximum number of bytes in the file to memory map.  The
1004 ** pointer is overwritten with the old value.  The limit is not changed if
1005 ** the value originally pointed to is negative, and so the current limit
1006 ** can be queried by passing in a pointer to a negative number.  This
1007 ** file-control is used internally to implement [PRAGMA mmap_size].
1008 **
1009 ** <li>[[SQLITE_FCNTL_TRACE]]
1010 ** The [SQLITE_FCNTL_TRACE] file control provides advisory information
1011 ** to the VFS about what the higher layers of the SQLite stack are doing.
1012 ** This file control is used by some VFS activity tracing [shims].
1013 ** The argument is a zero-terminated string.  Higher layers in the
1014 ** SQLite stack may generate instances of this file control if
1015 ** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled.
1016 **
1017 ** <li>[[SQLITE_FCNTL_HAS_MOVED]]
1018 ** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a
1019 ** pointer to an integer and it writes a boolean into that integer depending
1020 ** on whether or not the file has been renamed, moved, or deleted since it
1021 ** was first opened.
1022 **
1023 ** <li>[[SQLITE_FCNTL_WIN32_GET_HANDLE]]
1024 ** The [SQLITE_FCNTL_WIN32_GET_HANDLE] opcode can be used to obtain the
1025 ** underlying native file handle associated with a file handle.  This file
1026 ** control interprets its argument as a pointer to a native file handle and
1027 ** writes the resulting value there.
1028 **
1029 ** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]]
1030 ** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging.  This
1031 ** opcode causes the xFileControl method to swap the file handle with the one
1032 ** pointed to by the pArg argument.  This capability is used during testing
1033 ** and only needs to be supported when SQLITE_TEST is defined.
1034 **
1035 ** <li>[[SQLITE_FCNTL_WAL_BLOCK]]
1036 ** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might
1037 ** be advantageous to block on the next WAL lock if the lock is not immediately
1038 ** available.  The WAL subsystem issues this signal during rare
1039 ** circumstances in order to fix a problem with priority inversion.
1040 ** Applications should <em>not</em> use this file-control.
1041 **
1042 ** <li>[[SQLITE_FCNTL_ZIPVFS]]
1043 ** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other
1044 ** VFS should return SQLITE_NOTFOUND for this opcode.
1045 **
1046 ** <li>[[SQLITE_FCNTL_RBU]]
1047 ** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by
1048 ** the RBU extension only.  All other VFS should return SQLITE_NOTFOUND for
1049 ** this opcode.
1050 **
1051 ** <li>[[SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]]
1052 ** If the [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] opcode returns SQLITE_OK, then
1053 ** the file descriptor is placed in "batch write mode", which
1054 ** means all subsequent write operations will be deferred and done
1055 ** atomically at the next [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE].  Systems
1056 ** that do not support batch atomic writes will return SQLITE_NOTFOUND.
1057 ** ^Following a successful SQLITE_FCNTL_BEGIN_ATOMIC_WRITE and prior to
1058 ** the closing [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] or
1059 ** [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE], SQLite will make
1060 ** no VFS interface calls on the same [sqlite3_file] file descriptor
1061 ** except for calls to the xWrite method and the xFileControl method
1062 ** with [SQLITE_FCNTL_SIZE_HINT].
1063 **
1064 ** <li>[[SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]]
1065 ** The [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] opcode causes all write
1066 ** operations since the previous successful call to
1067 ** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be performed atomically.
1068 ** This file control returns [SQLITE_OK] if and only if the writes were
1069 ** all performed successfully and have been committed to persistent storage.
1070 ** ^Regardless of whether or not it is successful, this file control takes
1071 ** the file descriptor out of batch write mode so that all subsequent
1072 ** write operations are independent.
1073 ** ^SQLite will never invoke SQLITE_FCNTL_COMMIT_ATOMIC_WRITE without
1074 ** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE].
1075 **
1076 ** <li>[[SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE]]
1077 ** The [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE] opcode causes all write
1078 ** operations since the previous successful call to
1079 ** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be rolled back.
1080 ** ^This file control takes the file descriptor out of batch write mode
1081 ** so that all subsequent write operations are independent.
1082 ** ^SQLite will never invoke SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE without
1083 ** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE].
1084 **
1085 ** <li>[[SQLITE_FCNTL_LOCK_TIMEOUT]]
1086 ** The [SQLITE_FCNTL_LOCK_TIMEOUT] opcode causes attempts to obtain
1087 ** a file lock using the xLock or xShmLock methods of the VFS to wait
1088 ** for up to M milliseconds before failing, where M is the single
1089 ** unsigned integer parameter.
1090 **
1091 ** <li>[[SQLITE_FCNTL_DATA_VERSION]]
1092 ** The [SQLITE_FCNTL_DATA_VERSION] opcode is used to detect changes to
1093 ** a database file.  The argument is a pointer to a 32-bit unsigned integer.
1094 ** The "data version" for the pager is written into the pointer.  The
1095 ** "data version" changes whenever any change occurs to the corresponding
1096 ** database file, either through SQL statements on the same database
1097 ** connection or through transactions committed by separate database
1098 ** connections possibly in other processes. The [sqlite3_total_changes()]
1099 ** interface can be used to find if any database on the connection has changed,
1100 ** but that interface responds to changes on TEMP as well as MAIN and does
1101 ** not provide a mechanism to detect changes to MAIN only.  Also, the
1102 ** [sqlite3_total_changes()] interface responds to internal changes only and
1103 ** omits changes made by other database connections.  The
1104 ** [PRAGMA data_version] command provide a mechanism to detect changes to
1105 ** a single attached database that occur due to other database connections,
1106 ** but omits changes implemented by the database connection on which it is
1107 ** called.  This file control is the only mechanism to detect changes that
1108 ** happen either internally or externally and that are associated with
1109 ** a particular attached database.
1110 ** </ul>
1111 */
1112 #define SQLITE_FCNTL_LOCKSTATE               1
1113 #define SQLITE_FCNTL_GET_LOCKPROXYFILE       2
1114 #define SQLITE_FCNTL_SET_LOCKPROXYFILE       3
1115 #define SQLITE_FCNTL_LAST_ERRNO              4
1116 #define SQLITE_FCNTL_SIZE_HINT               5
1117 #define SQLITE_FCNTL_CHUNK_SIZE              6
1118 #define SQLITE_FCNTL_FILE_POINTER            7
1119 #define SQLITE_FCNTL_SYNC_OMITTED            8
1120 #define SQLITE_FCNTL_WIN32_AV_RETRY          9
1121 #define SQLITE_FCNTL_PERSIST_WAL            10
1122 #define SQLITE_FCNTL_OVERWRITE              11
1123 #define SQLITE_FCNTL_VFSNAME                12
1124 #define SQLITE_FCNTL_POWERSAFE_OVERWRITE    13
1125 #define SQLITE_FCNTL_PRAGMA                 14
1126 #define SQLITE_FCNTL_BUSYHANDLER            15
1127 #define SQLITE_FCNTL_TEMPFILENAME           16
1128 #define SQLITE_FCNTL_MMAP_SIZE              18
1129 #define SQLITE_FCNTL_TRACE                  19
1130 #define SQLITE_FCNTL_HAS_MOVED              20
1131 #define SQLITE_FCNTL_SYNC                   21
1132 #define SQLITE_FCNTL_COMMIT_PHASETWO        22
1133 #define SQLITE_FCNTL_WIN32_SET_HANDLE       23
1134 #define SQLITE_FCNTL_WAL_BLOCK              24
1135 #define SQLITE_FCNTL_ZIPVFS                 25
1136 #define SQLITE_FCNTL_RBU                    26
1137 #define SQLITE_FCNTL_VFS_POINTER            27
1138 #define SQLITE_FCNTL_JOURNAL_POINTER        28
1139 #define SQLITE_FCNTL_WIN32_GET_HANDLE       29
1140 #define SQLITE_FCNTL_PDB                    30
1141 #define SQLITE_FCNTL_BEGIN_ATOMIC_WRITE     31
1142 #define SQLITE_FCNTL_COMMIT_ATOMIC_WRITE    32
1143 #define SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE  33
1144 #define SQLITE_FCNTL_LOCK_TIMEOUT           34
1145 #define SQLITE_FCNTL_DATA_VERSION           35
1146 #define SQLITE_FCNTL_SIZE_LIMIT             36
1147 
1148 /* deprecated names */
1149 #define SQLITE_GET_LOCKPROXYFILE      SQLITE_FCNTL_GET_LOCKPROXYFILE
1150 #define SQLITE_SET_LOCKPROXYFILE      SQLITE_FCNTL_SET_LOCKPROXYFILE
1151 #define SQLITE_LAST_ERRNO             SQLITE_FCNTL_LAST_ERRNO
1152 
1153 
1154 /*
1155 ** CAPI3REF: Mutex Handle
1156 **
1157 ** The mutex module within SQLite defines [sqlite3_mutex] to be an
1158 ** abstract type for a mutex object.  The SQLite core never looks
1159 ** at the internal representation of an [sqlite3_mutex].  It only
1160 ** deals with pointers to the [sqlite3_mutex] object.
1161 **
1162 ** Mutexes are created using [sqlite3_mutex_alloc()].
1163 */
1164 typedef struct sqlite3_mutex sqlite3_mutex;
1165 
1166 /*
1167 ** CAPI3REF: Loadable Extension Thunk
1168 **
1169 ** A pointer to the opaque sqlite3_api_routines structure is passed as
1170 ** the third parameter to entry points of [loadable extensions].  This
1171 ** structure must be typedefed in order to work around compiler warnings
1172 ** on some platforms.
1173 */
1174 typedef struct sqlite3_api_routines sqlite3_api_routines;
1175 
1176 /*
1177 ** CAPI3REF: OS Interface Object
1178 **
1179 ** An instance of the sqlite3_vfs object defines the interface between
1180 ** the SQLite core and the underlying operating system.  The "vfs"
1181 ** in the name of the object stands for "virtual file system".  See
1182 ** the [VFS | VFS documentation] for further information.
1183 **
1184 ** The VFS interface is sometimes extended by adding new methods onto
1185 ** the end.  Each time such an extension occurs, the iVersion field
1186 ** is incremented.  The iVersion value started out as 1 in
1187 ** SQLite [version 3.5.0] on [dateof:3.5.0], then increased to 2
1188 ** with SQLite [version 3.7.0] on [dateof:3.7.0], and then increased
1189 ** to 3 with SQLite [version 3.7.6] on [dateof:3.7.6].  Additional fields
1190 ** may be appended to the sqlite3_vfs object and the iVersion value
1191 ** may increase again in future versions of SQLite.
1192 ** Note that the structure
1193 ** of the sqlite3_vfs object changes in the transition from
1194 ** SQLite [version 3.5.9] to [version 3.6.0] on [dateof:3.6.0]
1195 ** and yet the iVersion field was not modified.
1196 **
1197 ** The szOsFile field is the size of the subclassed [sqlite3_file]
1198 ** structure used by this VFS.  mxPathname is the maximum length of
1199 ** a pathname in this VFS.
1200 **
1201 ** Registered sqlite3_vfs objects are kept on a linked list formed by
1202 ** the pNext pointer.  The [sqlite3_vfs_register()]
1203 ** and [sqlite3_vfs_unregister()] interfaces manage this list
1204 ** in a thread-safe way.  The [sqlite3_vfs_find()] interface
1205 ** searches the list.  Neither the application code nor the VFS
1206 ** implementation should use the pNext pointer.
1207 **
1208 ** The pNext field is the only field in the sqlite3_vfs
1209 ** structure that SQLite will ever modify.  SQLite will only access
1210 ** or modify this field while holding a particular static mutex.
1211 ** The application should never modify anything within the sqlite3_vfs
1212 ** object once the object has been registered.
1213 **
1214 ** The zName field holds the name of the VFS module.  The name must
1215 ** be unique across all VFS modules.
1216 **
1217 ** [[sqlite3_vfs.xOpen]]
1218 ** ^SQLite guarantees that the zFilename parameter to xOpen
1219 ** is either a NULL pointer or string obtained
1220 ** from xFullPathname() with an optional suffix added.
1221 ** ^If a suffix is added to the zFilename parameter, it will
1222 ** consist of a single "-" character followed by no more than
1223 ** 11 alphanumeric and/or "-" characters.
1224 ** ^SQLite further guarantees that
1225 ** the string will be valid and unchanged until xClose() is
1226 ** called. Because of the previous sentence,
1227 ** the [sqlite3_file] can safely store a pointer to the
1228 ** filename if it needs to remember the filename for some reason.
1229 ** If the zFilename parameter to xOpen is a NULL pointer then xOpen
1230 ** must invent its own temporary name for the file.  ^Whenever the
1231 ** xFilename parameter is NULL it will also be the case that the
1232 ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
1233 **
1234 ** The flags argument to xOpen() includes all bits set in
1235 ** the flags argument to [sqlite3_open_v2()].  Or if [sqlite3_open()]
1236 ** or [sqlite3_open16()] is used, then flags includes at least
1237 ** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE].
1238 ** If xOpen() opens a file read-only then it sets *pOutFlags to
1239 ** include [SQLITE_OPEN_READONLY].  Other bits in *pOutFlags may be set.
1240 **
1241 ** ^(SQLite will also add one of the following flags to the xOpen()
1242 ** call, depending on the object being opened:
1243 **
1244 ** <ul>
1245 ** <li>  [SQLITE_OPEN_MAIN_DB]
1246 ** <li>  [SQLITE_OPEN_MAIN_JOURNAL]
1247 ** <li>  [SQLITE_OPEN_TEMP_DB]
1248 ** <li>  [SQLITE_OPEN_TEMP_JOURNAL]
1249 ** <li>  [SQLITE_OPEN_TRANSIENT_DB]
1250 ** <li>  [SQLITE_OPEN_SUBJOURNAL]
1251 ** <li>  [SQLITE_OPEN_MASTER_JOURNAL]
1252 ** <li>  [SQLITE_OPEN_WAL]
1253 ** </ul>)^
1254 **
1255 ** The file I/O implementation can use the object type flags to
1256 ** change the way it deals with files.  For example, an application
1257 ** that does not care about crash recovery or rollback might make
1258 ** the open of a journal file a no-op.  Writes to this journal would
1259 ** also be no-ops, and any attempt to read the journal would return
1260 ** SQLITE_IOERR.  Or the implementation might recognize that a database
1261 ** file will be doing page-aligned sector reads and writes in a random
1262 ** order and set up its I/O subsystem accordingly.
1263 **
1264 ** SQLite might also add one of the following flags to the xOpen method:
1265 **
1266 ** <ul>
1267 ** <li> [SQLITE_OPEN_DELETEONCLOSE]
1268 ** <li> [SQLITE_OPEN_EXCLUSIVE]
1269 ** </ul>
1270 **
1271 ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
1272 ** deleted when it is closed.  ^The [SQLITE_OPEN_DELETEONCLOSE]
1273 ** will be set for TEMP databases and their journals, transient
1274 ** databases, and subjournals.
1275 **
1276 ** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
1277 ** with the [SQLITE_OPEN_CREATE] flag, which are both directly
1278 ** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
1279 ** API.  The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
1280 ** SQLITE_OPEN_CREATE, is used to indicate that file should always
1281 ** be created, and that it is an error if it already exists.
1282 ** It is <i>not</i> used to indicate the file should be opened
1283 ** for exclusive access.
1284 **
1285 ** ^At least szOsFile bytes of memory are allocated by SQLite
1286 ** to hold the  [sqlite3_file] structure passed as the third
1287 ** argument to xOpen.  The xOpen method does not have to
1288 ** allocate the structure; it should just fill it in.  Note that
1289 ** the xOpen method must set the sqlite3_file.pMethods to either
1290 ** a valid [sqlite3_io_methods] object or to NULL.  xOpen must do
1291 ** this even if the open fails.  SQLite expects that the sqlite3_file.pMethods
1292 ** element will be valid after xOpen returns regardless of the success
1293 ** or failure of the xOpen call.
1294 **
1295 ** [[sqlite3_vfs.xAccess]]
1296 ** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
1297 ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
1298 ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
1299 ** to test whether a file is at least readable.  The SQLITE_ACCESS_READ
1300 ** flag is never actually used and is not implemented in the built-in
1301 ** VFSes of SQLite.  The file is named by the second argument and can be a
1302 ** directory. The xAccess method returns [SQLITE_OK] on success or some
1303 ** non-zero error code if there is an I/O error or if the name of
1304 ** the file given in the second argument is illegal.  If SQLITE_OK
1305 ** is returned, then non-zero or zero is written into *pResOut to indicate
1306 ** whether or not the file is accessible.
1307 **
1308 ** ^SQLite will always allocate at least mxPathname+1 bytes for the
1309 ** output buffer xFullPathname.  The exact size of the output buffer
1310 ** is also passed as a parameter to both  methods. If the output buffer
1311 ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
1312 ** handled as a fatal error by SQLite, vfs implementations should endeavor
1313 ** to prevent this by setting mxPathname to a sufficiently large value.
1314 **
1315 ** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
1316 ** interfaces are not strictly a part of the filesystem, but they are
1317 ** included in the VFS structure for completeness.
1318 ** The xRandomness() function attempts to return nBytes bytes
1319 ** of good-quality randomness into zOut.  The return value is
1320 ** the actual number of bytes of randomness obtained.
1321 ** The xSleep() method causes the calling thread to sleep for at
1322 ** least the number of microseconds given.  ^The xCurrentTime()
1323 ** method returns a Julian Day Number for the current date and time as
1324 ** a floating point value.
1325 ** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
1326 ** Day Number multiplied by 86400000 (the number of milliseconds in
1327 ** a 24-hour day).
1328 ** ^SQLite will use the xCurrentTimeInt64() method to get the current
1329 ** date and time if that method is available (if iVersion is 2 or
1330 ** greater and the function pointer is not NULL) and will fall back
1331 ** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
1332 **
1333 ** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
1334 ** are not used by the SQLite core.  These optional interfaces are provided
1335 ** by some VFSes to facilitate testing of the VFS code. By overriding
1336 ** system calls with functions under its control, a test program can
1337 ** simulate faults and error conditions that would otherwise be difficult
1338 ** or impossible to induce.  The set of system calls that can be overridden
1339 ** varies from one VFS to another, and from one version of the same VFS to the
1340 ** next.  Applications that use these interfaces must be prepared for any
1341 ** or all of these interfaces to be NULL or for their behavior to change
1342 ** from one release to the next.  Applications must not attempt to access
1343 ** any of these methods if the iVersion of the VFS is less than 3.
1344 */
1345 typedef struct sqlite3_vfs sqlite3_vfs;
1346 typedef void (*sqlite3_syscall_ptr)(void);
1347 struct sqlite3_vfs {
1348   int iVersion;            /* Structure version number (currently 3) */
1349   int szOsFile;            /* Size of subclassed sqlite3_file */
1350   int mxPathname;          /* Maximum file pathname length */
1351   sqlite3_vfs *pNext;      /* Next registered VFS */
1352   const char *zName;       /* Name of this virtual file system */
1353   void *pAppData;          /* Pointer to application-specific data */
1354   int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
1355                int flags, int *pOutFlags);
1356   int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
1357   int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
1358   int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
1359   void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
1360   void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
1361   void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
1362   void (*xDlClose)(sqlite3_vfs*, void*);
1363   int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
1364   int (*xSleep)(sqlite3_vfs*, int microseconds);
1365   int (*xCurrentTime)(sqlite3_vfs*, double*);
1366   int (*xGetLastError)(sqlite3_vfs*, int, char *);
1367   /*
1368   ** The methods above are in version 1 of the sqlite_vfs object
1369   ** definition.  Those that follow are added in version 2 or later
1370   */
1371   int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
1372   /*
1373   ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
1374   ** Those below are for version 3 and greater.
1375   */
1376   int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
1377   sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
1378   const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
1379   /*
1380   ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
1381   ** New fields may be appended in future versions.  The iVersion
1382   ** value will increment whenever this happens.
1383   */
1384 };
1385 
1386 /*
1387 ** CAPI3REF: Flags for the xAccess VFS method
1388 **
1389 ** These integer constants can be used as the third parameter to
1390 ** the xAccess method of an [sqlite3_vfs] object.  They determine
1391 ** what kind of permissions the xAccess method is looking for.
1392 ** With SQLITE_ACCESS_EXISTS, the xAccess method
1393 ** simply checks whether the file exists.
1394 ** With SQLITE_ACCESS_READWRITE, the xAccess method
1395 ** checks whether the named directory is both readable and writable
1396 ** (in other words, if files can be added, removed, and renamed within
1397 ** the directory).
1398 ** The SQLITE_ACCESS_READWRITE constant is currently used only by the
1399 ** [temp_store_directory pragma], though this could change in a future
1400 ** release of SQLite.
1401 ** With SQLITE_ACCESS_READ, the xAccess method
1402 ** checks whether the file is readable.  The SQLITE_ACCESS_READ constant is
1403 ** currently unused, though it might be used in a future release of
1404 ** SQLite.
1405 */
1406 #define SQLITE_ACCESS_EXISTS    0
1407 #define SQLITE_ACCESS_READWRITE 1   /* Used by PRAGMA temp_store_directory */
1408 #define SQLITE_ACCESS_READ      2   /* Unused */
1409 
1410 /*
1411 ** CAPI3REF: Flags for the xShmLock VFS method
1412 **
1413 ** These integer constants define the various locking operations
1414 ** allowed by the xShmLock method of [sqlite3_io_methods].  The
1415 ** following are the only legal combinations of flags to the
1416 ** xShmLock method:
1417 **
1418 ** <ul>
1419 ** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
1420 ** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
1421 ** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
1422 ** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
1423 ** </ul>
1424 **
1425 ** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
1426 ** was given on the corresponding lock.
1427 **
1428 ** The xShmLock method can transition between unlocked and SHARED or
1429 ** between unlocked and EXCLUSIVE.  It cannot transition between SHARED
1430 ** and EXCLUSIVE.
1431 */
1432 #define SQLITE_SHM_UNLOCK       1
1433 #define SQLITE_SHM_LOCK         2
1434 #define SQLITE_SHM_SHARED       4
1435 #define SQLITE_SHM_EXCLUSIVE    8
1436 
1437 /*
1438 ** CAPI3REF: Maximum xShmLock index
1439 **
1440 ** The xShmLock method on [sqlite3_io_methods] may use values
1441 ** between 0 and this upper bound as its "offset" argument.
1442 ** The SQLite core will never attempt to acquire or release a
1443 ** lock outside of this range
1444 */
1445 #define SQLITE_SHM_NLOCK        8
1446 
1447 
1448 /*
1449 ** CAPI3REF: Initialize The SQLite Library
1450 **
1451 ** ^The sqlite3_initialize() routine initializes the
1452 ** SQLite library.  ^The sqlite3_shutdown() routine
1453 ** deallocates any resources that were allocated by sqlite3_initialize().
1454 ** These routines are designed to aid in process initialization and
1455 ** shutdown on embedded systems.  Workstation applications using
1456 ** SQLite normally do not need to invoke either of these routines.
1457 **
1458 ** A call to sqlite3_initialize() is an "effective" call if it is
1459 ** the first time sqlite3_initialize() is invoked during the lifetime of
1460 ** the process, or if it is the first time sqlite3_initialize() is invoked
1461 ** following a call to sqlite3_shutdown().  ^(Only an effective call
1462 ** of sqlite3_initialize() does any initialization.  All other calls
1463 ** are harmless no-ops.)^
1464 **
1465 ** A call to sqlite3_shutdown() is an "effective" call if it is the first
1466 ** call to sqlite3_shutdown() since the last sqlite3_initialize().  ^(Only
1467 ** an effective call to sqlite3_shutdown() does any deinitialization.
1468 ** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
1469 **
1470 ** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
1471 ** is not.  The sqlite3_shutdown() interface must only be called from a
1472 ** single thread.  All open [database connections] must be closed and all
1473 ** other SQLite resources must be deallocated prior to invoking
1474 ** sqlite3_shutdown().
1475 **
1476 ** Among other things, ^sqlite3_initialize() will invoke
1477 ** sqlite3_os_init().  Similarly, ^sqlite3_shutdown()
1478 ** will invoke sqlite3_os_end().
1479 **
1480 ** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
1481 ** ^If for some reason, sqlite3_initialize() is unable to initialize
1482 ** the library (perhaps it is unable to allocate a needed resource such
1483 ** as a mutex) it returns an [error code] other than [SQLITE_OK].
1484 **
1485 ** ^The sqlite3_initialize() routine is called internally by many other
1486 ** SQLite interfaces so that an application usually does not need to
1487 ** invoke sqlite3_initialize() directly.  For example, [sqlite3_open()]
1488 ** calls sqlite3_initialize() so the SQLite library will be automatically
1489 ** initialized when [sqlite3_open()] is called if it has not be initialized
1490 ** already.  ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
1491 ** compile-time option, then the automatic calls to sqlite3_initialize()
1492 ** are omitted and the application must call sqlite3_initialize() directly
1493 ** prior to using any other SQLite interface.  For maximum portability,
1494 ** it is recommended that applications always invoke sqlite3_initialize()
1495 ** directly prior to using any other SQLite interface.  Future releases
1496 ** of SQLite may require this.  In other words, the behavior exhibited
1497 ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
1498 ** default behavior in some future release of SQLite.
1499 **
1500 ** The sqlite3_os_init() routine does operating-system specific
1501 ** initialization of the SQLite library.  The sqlite3_os_end()
1502 ** routine undoes the effect of sqlite3_os_init().  Typical tasks
1503 ** performed by these routines include allocation or deallocation
1504 ** of static resources, initialization of global variables,
1505 ** setting up a default [sqlite3_vfs] module, or setting up
1506 ** a default configuration using [sqlite3_config()].
1507 **
1508 ** The application should never invoke either sqlite3_os_init()
1509 ** or sqlite3_os_end() directly.  The application should only invoke
1510 ** sqlite3_initialize() and sqlite3_shutdown().  The sqlite3_os_init()
1511 ** interface is called automatically by sqlite3_initialize() and
1512 ** sqlite3_os_end() is called by sqlite3_shutdown().  Appropriate
1513 ** implementations for sqlite3_os_init() and sqlite3_os_end()
1514 ** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
1515 ** When [custom builds | built for other platforms]
1516 ** (using the [SQLITE_OS_OTHER=1] compile-time
1517 ** option) the application must supply a suitable implementation for
1518 ** sqlite3_os_init() and sqlite3_os_end().  An application-supplied
1519 ** implementation of sqlite3_os_init() or sqlite3_os_end()
1520 ** must return [SQLITE_OK] on success and some other [error code] upon
1521 ** failure.
1522 */
1523 SQLITE_API int sqlite3_initialize(void);
1524 SQLITE_API int sqlite3_shutdown(void);
1525 SQLITE_API int sqlite3_os_init(void);
1526 SQLITE_API int sqlite3_os_end(void);
1527 
1528 /*
1529 ** CAPI3REF: Configuring The SQLite Library
1530 **
1531 ** The sqlite3_config() interface is used to make global configuration
1532 ** changes to SQLite in order to tune SQLite to the specific needs of
1533 ** the application.  The default configuration is recommended for most
1534 ** applications and so this routine is usually not necessary.  It is
1535 ** provided to support rare applications with unusual needs.
1536 **
1537 ** <b>The sqlite3_config() interface is not threadsafe. The application
1538 ** must ensure that no other SQLite interfaces are invoked by other
1539 ** threads while sqlite3_config() is running.</b>
1540 **
1541 ** The sqlite3_config() interface
1542 ** may only be invoked prior to library initialization using
1543 ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
1544 ** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
1545 ** [sqlite3_shutdown()] then it will return SQLITE_MISUSE.
1546 ** Note, however, that ^sqlite3_config() can be called as part of the
1547 ** implementation of an application-defined [sqlite3_os_init()].
1548 **
1549 ** The first argument to sqlite3_config() is an integer
1550 ** [configuration option] that determines
1551 ** what property of SQLite is to be configured.  Subsequent arguments
1552 ** vary depending on the [configuration option]
1553 ** in the first argument.
1554 **
1555 ** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
1556 ** ^If the option is unknown or SQLite is unable to set the option
1557 ** then this routine returns a non-zero [error code].
1558 */
1559 SQLITE_API int sqlite3_config(int, ...);
1560 
1561 /*
1562 ** CAPI3REF: Configure database connections
1563 ** METHOD: sqlite3
1564 **
1565 ** The sqlite3_db_config() interface is used to make configuration
1566 ** changes to a [database connection].  The interface is similar to
1567 ** [sqlite3_config()] except that the changes apply to a single
1568 ** [database connection] (specified in the first argument).
1569 **
1570 ** The second argument to sqlite3_db_config(D,V,...)  is the
1571 ** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code
1572 ** that indicates what aspect of the [database connection] is being configured.
1573 ** Subsequent arguments vary depending on the configuration verb.
1574 **
1575 ** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
1576 ** the call is considered successful.
1577 */
1578 SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...);
1579 
1580 /*
1581 ** CAPI3REF: Memory Allocation Routines
1582 **
1583 ** An instance of this object defines the interface between SQLite
1584 ** and low-level memory allocation routines.
1585 **
1586 ** This object is used in only one place in the SQLite interface.
1587 ** A pointer to an instance of this object is the argument to
1588 ** [sqlite3_config()] when the configuration option is
1589 ** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].
1590 ** By creating an instance of this object
1591 ** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
1592 ** during configuration, an application can specify an alternative
1593 ** memory allocation subsystem for SQLite to use for all of its
1594 ** dynamic memory needs.
1595 **
1596 ** Note that SQLite comes with several [built-in memory allocators]
1597 ** that are perfectly adequate for the overwhelming majority of applications
1598 ** and that this object is only useful to a tiny minority of applications
1599 ** with specialized memory allocation requirements.  This object is
1600 ** also used during testing of SQLite in order to specify an alternative
1601 ** memory allocator that simulates memory out-of-memory conditions in
1602 ** order to verify that SQLite recovers gracefully from such
1603 ** conditions.
1604 **
1605 ** The xMalloc, xRealloc, and xFree methods must work like the
1606 ** malloc(), realloc() and free() functions from the standard C library.
1607 ** ^SQLite guarantees that the second argument to
1608 ** xRealloc is always a value returned by a prior call to xRoundup.
1609 **
1610 ** xSize should return the allocated size of a memory allocation
1611 ** previously obtained from xMalloc or xRealloc.  The allocated size
1612 ** is always at least as big as the requested size but may be larger.
1613 **
1614 ** The xRoundup method returns what would be the allocated size of
1615 ** a memory allocation given a particular requested size.  Most memory
1616 ** allocators round up memory allocations at least to the next multiple
1617 ** of 8.  Some allocators round up to a larger multiple or to a power of 2.
1618 ** Every memory allocation request coming in through [sqlite3_malloc()]
1619 ** or [sqlite3_realloc()] first calls xRoundup.  If xRoundup returns 0,
1620 ** that causes the corresponding memory allocation to fail.
1621 **
1622 ** The xInit method initializes the memory allocator.  For example,
1623 ** it might allocate any require mutexes or initialize internal data
1624 ** structures.  The xShutdown method is invoked (indirectly) by
1625 ** [sqlite3_shutdown()] and should deallocate any resources acquired
1626 ** by xInit.  The pAppData pointer is used as the only parameter to
1627 ** xInit and xShutdown.
1628 **
1629 ** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes
1630 ** the xInit method, so the xInit method need not be threadsafe.  The
1631 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
1632 ** not need to be threadsafe either.  For all other methods, SQLite
1633 ** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
1634 ** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
1635 ** it is by default) and so the methods are automatically serialized.
1636 ** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
1637 ** methods must be threadsafe or else make their own arrangements for
1638 ** serialization.
1639 **
1640 ** SQLite will never invoke xInit() more than once without an intervening
1641 ** call to xShutdown().
1642 */
1643 typedef struct sqlite3_mem_methods sqlite3_mem_methods;
1644 struct sqlite3_mem_methods {
1645   void *(*xMalloc)(int);         /* Memory allocation function */
1646   void (*xFree)(void*);          /* Free a prior allocation */
1647   void *(*xRealloc)(void*,int);  /* Resize an allocation */
1648   int (*xSize)(void*);           /* Return the size of an allocation */
1649   int (*xRoundup)(int);          /* Round up request size to allocation size */
1650   int (*xInit)(void*);           /* Initialize the memory allocator */
1651   void (*xShutdown)(void*);      /* Deinitialize the memory allocator */
1652   void *pAppData;                /* Argument to xInit() and xShutdown() */
1653 };
1654 
1655 /*
1656 ** CAPI3REF: Configuration Options
1657 ** KEYWORDS: {configuration option}
1658 **
1659 ** These constants are the available integer configuration options that
1660 ** can be passed as the first argument to the [sqlite3_config()] interface.
1661 **
1662 ** New configuration options may be added in future releases of SQLite.
1663 ** Existing configuration options might be discontinued.  Applications
1664 ** should check the return code from [sqlite3_config()] to make sure that
1665 ** the call worked.  The [sqlite3_config()] interface will return a
1666 ** non-zero [error code] if a discontinued or unsupported configuration option
1667 ** is invoked.
1668 **
1669 ** <dl>
1670 ** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
1671 ** <dd>There are no arguments to this option.  ^This option sets the
1672 ** [threading mode] to Single-thread.  In other words, it disables
1673 ** all mutexing and puts SQLite into a mode where it can only be used
1674 ** by a single thread.   ^If SQLite is compiled with
1675 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1676 ** it is not possible to change the [threading mode] from its default
1677 ** value of Single-thread and so [sqlite3_config()] will return
1678 ** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
1679 ** configuration option.</dd>
1680 **
1681 ** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt>
1682 ** <dd>There are no arguments to this option.  ^This option sets the
1683 ** [threading mode] to Multi-thread.  In other words, it disables
1684 ** mutexing on [database connection] and [prepared statement] objects.
1685 ** The application is responsible for serializing access to
1686 ** [database connections] and [prepared statements].  But other mutexes
1687 ** are enabled so that SQLite will be safe to use in a multi-threaded
1688 ** environment as long as no two threads attempt to use the same
1689 ** [database connection] at the same time.  ^If SQLite is compiled with
1690 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1691 ** it is not possible to set the Multi-thread [threading mode] and
1692 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1693 ** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
1694 **
1695 ** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt>
1696 ** <dd>There are no arguments to this option.  ^This option sets the
1697 ** [threading mode] to Serialized. In other words, this option enables
1698 ** all mutexes including the recursive
1699 ** mutexes on [database connection] and [prepared statement] objects.
1700 ** In this mode (which is the default when SQLite is compiled with
1701 ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
1702 ** to [database connections] and [prepared statements] so that the
1703 ** application is free to use the same [database connection] or the
1704 ** same [prepared statement] in different threads at the same time.
1705 ** ^If SQLite is compiled with
1706 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1707 ** it is not possible to set the Serialized [threading mode] and
1708 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1709 ** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
1710 **
1711 ** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt>
1712 ** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is
1713 ** a pointer to an instance of the [sqlite3_mem_methods] structure.
1714 ** The argument specifies
1715 ** alternative low-level memory allocation routines to be used in place of
1716 ** the memory allocation routines built into SQLite.)^ ^SQLite makes
1717 ** its own private copy of the content of the [sqlite3_mem_methods] structure
1718 ** before the [sqlite3_config()] call returns.</dd>
1719 **
1720 ** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt>
1721 ** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which
1722 ** is a pointer to an instance of the [sqlite3_mem_methods] structure.
1723 ** The [sqlite3_mem_methods]
1724 ** structure is filled with the currently defined memory allocation routines.)^
1725 ** This option can be used to overload the default memory allocation
1726 ** routines with a wrapper that simulations memory allocation failure or
1727 ** tracks memory usage, for example. </dd>
1728 **
1729 ** [[SQLITE_CONFIG_SMALL_MALLOC]] <dt>SQLITE_CONFIG_SMALL_MALLOC</dt>
1730 ** <dd> ^The SQLITE_CONFIG_SMALL_MALLOC option takes single argument of
1731 ** type int, interpreted as a boolean, which if true provides a hint to
1732 ** SQLite that it should avoid large memory allocations if possible.
1733 ** SQLite will run faster if it is free to make large memory allocations,
1734 ** but some application might prefer to run slower in exchange for
1735 ** guarantees about memory fragmentation that are possible if large
1736 ** allocations are avoided.  This hint is normally off.
1737 ** </dd>
1738 **
1739 ** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt>
1740 ** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int,
1741 ** interpreted as a boolean, which enables or disables the collection of
1742 ** memory allocation statistics. ^(When memory allocation statistics are
1743 ** disabled, the following SQLite interfaces become non-operational:
1744 **   <ul>
1745 **   <li> [sqlite3_memory_used()]
1746 **   <li> [sqlite3_memory_highwater()]
1747 **   <li> [sqlite3_soft_heap_limit64()]
1748 **   <li> [sqlite3_status64()]
1749 **   </ul>)^
1750 ** ^Memory allocation statistics are enabled by default unless SQLite is
1751 ** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
1752 ** allocation statistics are disabled by default.
1753 ** </dd>
1754 **
1755 ** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt>
1756 ** <dd> The SQLITE_CONFIG_SCRATCH option is no longer used.
1757 ** </dd>
1758 **
1759 ** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>
1760 ** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool
1761 ** that SQLite can use for the database page cache with the default page
1762 ** cache implementation.
1763 ** This configuration option is a no-op if an application-define page
1764 ** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2].
1765 ** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to
1766 ** 8-byte aligned memory (pMem), the size of each page cache line (sz),
1767 ** and the number of cache lines (N).
1768 ** The sz argument should be the size of the largest database page
1769 ** (a power of two between 512 and 65536) plus some extra bytes for each
1770 ** page header.  ^The number of extra bytes needed by the page header
1771 ** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ].
1772 ** ^It is harmless, apart from the wasted memory,
1773 ** for the sz parameter to be larger than necessary.  The pMem
1774 ** argument must be either a NULL pointer or a pointer to an 8-byte
1775 ** aligned block of memory of at least sz*N bytes, otherwise
1776 ** subsequent behavior is undefined.
1777 ** ^When pMem is not NULL, SQLite will strive to use the memory provided
1778 ** to satisfy page cache needs, falling back to [sqlite3_malloc()] if
1779 ** a page cache line is larger than sz bytes or if all of the pMem buffer
1780 ** is exhausted.
1781 ** ^If pMem is NULL and N is non-zero, then each database connection
1782 ** does an initial bulk allocation for page cache memory
1783 ** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or
1784 ** of -1024*N bytes if N is negative, . ^If additional
1785 ** page cache memory is needed beyond what is provided by the initial
1786 ** allocation, then SQLite goes to [sqlite3_malloc()] separately for each
1787 ** additional cache line. </dd>
1788 **
1789 ** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt>
1790 ** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer
1791 ** that SQLite will use for all of its dynamic memory allocation needs
1792 ** beyond those provided for by [SQLITE_CONFIG_PAGECACHE].
1793 ** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled
1794 ** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns
1795 ** [SQLITE_ERROR] if invoked otherwise.
1796 ** ^There are three arguments to SQLITE_CONFIG_HEAP:
1797 ** An 8-byte aligned pointer to the memory,
1798 ** the number of bytes in the memory buffer, and the minimum allocation size.
1799 ** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
1800 ** to using its default memory allocator (the system malloc() implementation),
1801 ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC].  ^If the
1802 ** memory pointer is not NULL then the alternative memory
1803 ** allocator is engaged to handle all of SQLites memory allocation needs.
1804 ** The first pointer (the memory pointer) must be aligned to an 8-byte
1805 ** boundary or subsequent behavior of SQLite will be undefined.
1806 ** The minimum allocation size is capped at 2**12. Reasonable values
1807 ** for the minimum allocation size are 2**5 through 2**8.</dd>
1808 **
1809 ** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt>
1810 ** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a
1811 ** pointer to an instance of the [sqlite3_mutex_methods] structure.
1812 ** The argument specifies alternative low-level mutex routines to be used
1813 ** in place the mutex routines built into SQLite.)^  ^SQLite makes a copy of
1814 ** the content of the [sqlite3_mutex_methods] structure before the call to
1815 ** [sqlite3_config()] returns. ^If SQLite is compiled with
1816 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1817 ** the entire mutexing subsystem is omitted from the build and hence calls to
1818 ** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
1819 ** return [SQLITE_ERROR].</dd>
1820 **
1821 ** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt>
1822 ** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which
1823 ** is a pointer to an instance of the [sqlite3_mutex_methods] structure.  The
1824 ** [sqlite3_mutex_methods]
1825 ** structure is filled with the currently defined mutex routines.)^
1826 ** This option can be used to overload the default mutex allocation
1827 ** routines with a wrapper used to track mutex usage for performance
1828 ** profiling or testing, for example.   ^If SQLite is compiled with
1829 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1830 ** the entire mutexing subsystem is omitted from the build and hence calls to
1831 ** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
1832 ** return [SQLITE_ERROR].</dd>
1833 **
1834 ** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt>
1835 ** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine
1836 ** the default size of lookaside memory on each [database connection].
1837 ** The first argument is the
1838 ** size of each lookaside buffer slot and the second is the number of
1839 ** slots allocated to each database connection.)^  ^(SQLITE_CONFIG_LOOKASIDE
1840 ** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
1841 ** option to [sqlite3_db_config()] can be used to change the lookaside
1842 ** configuration on individual connections.)^ </dd>
1843 **
1844 ** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt>
1845 ** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is
1846 ** a pointer to an [sqlite3_pcache_methods2] object.  This object specifies
1847 ** the interface to a custom page cache implementation.)^
1848 ** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd>
1849 **
1850 ** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt>
1851 ** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which
1852 ** is a pointer to an [sqlite3_pcache_methods2] object.  SQLite copies of
1853 ** the current page cache implementation into that object.)^ </dd>
1854 **
1855 ** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>
1856 ** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite
1857 ** global [error log].
1858 ** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
1859 ** function with a call signature of void(*)(void*,int,const char*),
1860 ** and a pointer to void. ^If the function pointer is not NULL, it is
1861 ** invoked by [sqlite3_log()] to process each logging event.  ^If the
1862 ** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
1863 ** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
1864 ** passed through as the first parameter to the application-defined logger
1865 ** function whenever that function is invoked.  ^The second parameter to
1866 ** the logger function is a copy of the first parameter to the corresponding
1867 ** [sqlite3_log()] call and is intended to be a [result code] or an
1868 ** [extended result code].  ^The third parameter passed to the logger is
1869 ** log message after formatting via [sqlite3_snprintf()].
1870 ** The SQLite logging interface is not reentrant; the logger function
1871 ** supplied by the application must not invoke any SQLite interface.
1872 ** In a multi-threaded application, the application-defined logger
1873 ** function must be threadsafe. </dd>
1874 **
1875 ** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI
1876 ** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int.
1877 ** If non-zero, then URI handling is globally enabled. If the parameter is zero,
1878 ** then URI handling is globally disabled.)^ ^If URI handling is globally
1879 ** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()],
1880 ** [sqlite3_open16()] or
1881 ** specified as part of [ATTACH] commands are interpreted as URIs, regardless
1882 ** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
1883 ** connection is opened. ^If it is globally disabled, filenames are
1884 ** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
1885 ** database connection is opened. ^(By default, URI handling is globally
1886 ** disabled. The default value may be changed by compiling with the
1887 ** [SQLITE_USE_URI] symbol defined.)^
1888 **
1889 ** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN
1890 ** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer
1891 ** argument which is interpreted as a boolean in order to enable or disable
1892 ** the use of covering indices for full table scans in the query optimizer.
1893 ** ^The default setting is determined
1894 ** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on"
1895 ** if that compile-time option is omitted.
1896 ** The ability to disable the use of covering indices for full table scans
1897 ** is because some incorrectly coded legacy applications might malfunction
1898 ** when the optimization is enabled.  Providing the ability to
1899 ** disable the optimization allows the older, buggy application code to work
1900 ** without change even with newer versions of SQLite.
1901 **
1902 ** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]]
1903 ** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE
1904 ** <dd> These options are obsolete and should not be used by new code.
1905 ** They are retained for backwards compatibility but are now no-ops.
1906 ** </dd>
1907 **
1908 ** [[SQLITE_CONFIG_SQLLOG]]
1909 ** <dt>SQLITE_CONFIG_SQLLOG
1910 ** <dd>This option is only available if sqlite is compiled with the
1911 ** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should
1912 ** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int).
1913 ** The second should be of type (void*). The callback is invoked by the library
1914 ** in three separate circumstances, identified by the value passed as the
1915 ** fourth parameter. If the fourth parameter is 0, then the database connection
1916 ** passed as the second argument has just been opened. The third argument
1917 ** points to a buffer containing the name of the main database file. If the
1918 ** fourth parameter is 1, then the SQL statement that the third parameter
1919 ** points to has just been executed. Or, if the fourth parameter is 2, then
1920 ** the connection being passed as the second parameter is being closed. The
1921 ** third parameter is passed NULL In this case.  An example of using this
1922 ** configuration option can be seen in the "test_sqllog.c" source file in
1923 ** the canonical SQLite source tree.</dd>
1924 **
1925 ** [[SQLITE_CONFIG_MMAP_SIZE]]
1926 ** <dt>SQLITE_CONFIG_MMAP_SIZE
1927 ** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values
1928 ** that are the default mmap size limit (the default setting for
1929 ** [PRAGMA mmap_size]) and the maximum allowed mmap size limit.
1930 ** ^The default setting can be overridden by each database connection using
1931 ** either the [PRAGMA mmap_size] command, or by using the
1932 ** [SQLITE_FCNTL_MMAP_SIZE] file control.  ^(The maximum allowed mmap size
1933 ** will be silently truncated if necessary so that it does not exceed the
1934 ** compile-time maximum mmap size set by the
1935 ** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^
1936 ** ^If either argument to this option is negative, then that argument is
1937 ** changed to its compile-time default.
1938 **
1939 ** [[SQLITE_CONFIG_WIN32_HEAPSIZE]]
1940 ** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE
1941 ** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is
1942 ** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro
1943 ** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value
1944 ** that specifies the maximum size of the created heap.
1945 **
1946 ** [[SQLITE_CONFIG_PCACHE_HDRSZ]]
1947 ** <dt>SQLITE_CONFIG_PCACHE_HDRSZ
1948 ** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which
1949 ** is a pointer to an integer and writes into that integer the number of extra
1950 ** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE].
1951 ** The amount of extra space required can change depending on the compiler,
1952 ** target platform, and SQLite version.
1953 **
1954 ** [[SQLITE_CONFIG_PMASZ]]
1955 ** <dt>SQLITE_CONFIG_PMASZ
1956 ** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which
1957 ** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded
1958 ** sorter to that integer.  The default minimum PMA Size is set by the
1959 ** [SQLITE_SORTER_PMASZ] compile-time option.  New threads are launched
1960 ** to help with sort operations when multithreaded sorting
1961 ** is enabled (using the [PRAGMA threads] command) and the amount of content
1962 ** to be sorted exceeds the page size times the minimum of the
1963 ** [PRAGMA cache_size] setting and this value.
1964 **
1965 ** [[SQLITE_CONFIG_STMTJRNL_SPILL]]
1966 ** <dt>SQLITE_CONFIG_STMTJRNL_SPILL
1967 ** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which
1968 ** becomes the [statement journal] spill-to-disk threshold.
1969 ** [Statement journals] are held in memory until their size (in bytes)
1970 ** exceeds this threshold, at which point they are written to disk.
1971 ** Or if the threshold is -1, statement journals are always held
1972 ** exclusively in memory.
1973 ** Since many statement journals never become large, setting the spill
1974 ** threshold to a value such as 64KiB can greatly reduce the amount of
1975 ** I/O required to support statement rollback.
1976 ** The default value for this setting is controlled by the
1977 ** [SQLITE_STMTJRNL_SPILL] compile-time option.
1978 **
1979 ** [[SQLITE_CONFIG_SORTERREF_SIZE]]
1980 ** <dt>SQLITE_CONFIG_SORTERREF_SIZE
1981 ** <dd>The SQLITE_CONFIG_SORTERREF_SIZE option accepts a single parameter
1982 ** of type (int) - the new value of the sorter-reference size threshold.
1983 ** Usually, when SQLite uses an external sort to order records according
1984 ** to an ORDER BY clause, all fields required by the caller are present in the
1985 ** sorted records. However, if SQLite determines based on the declared type
1986 ** of a table column that its values are likely to be very large - larger
1987 ** than the configured sorter-reference size threshold - then a reference
1988 ** is stored in each sorted record and the required column values loaded
1989 ** from the database as records are returned in sorted order. The default
1990 ** value for this option is to never use this optimization. Specifying a
1991 ** negative value for this option restores the default behaviour.
1992 ** This option is only available if SQLite is compiled with the
1993 ** [SQLITE_ENABLE_SORTER_REFERENCES] compile-time option.
1994 **
1995 ** [[SQLITE_CONFIG_MEMDB_MAXSIZE]]
1996 ** <dt>SQLITE_CONFIG_MEMDB_MAXSIZE
1997 ** <dd>The SQLITE_CONFIG_MEMDB_MAXSIZE option accepts a single parameter
1998 ** [sqlite3_int64] parameter which is the default maximum size for an in-memory
1999 ** database created using [sqlite3_deserialize()].  This default maximum
2000 ** size can be adjusted up or down for individual databases using the
2001 ** [SQLITE_FCNTL_SIZE_LIMIT] [sqlite3_file_control|file-control].  If this
2002 ** configuration setting is never used, then the default maximum is determined
2003 ** by the [SQLITE_MEMDB_DEFAULT_MAXSIZE] compile-time option.  If that
2004 ** compile-time option is not set, then the default maximum is 1073741824.
2005 ** </dl>
2006 */
2007 #define SQLITE_CONFIG_SINGLETHREAD  1  /* nil */
2008 #define SQLITE_CONFIG_MULTITHREAD   2  /* nil */
2009 #define SQLITE_CONFIG_SERIALIZED    3  /* nil */
2010 #define SQLITE_CONFIG_MALLOC        4  /* sqlite3_mem_methods* */
2011 #define SQLITE_CONFIG_GETMALLOC     5  /* sqlite3_mem_methods* */
2012 #define SQLITE_CONFIG_SCRATCH       6  /* No longer used */
2013 #define SQLITE_CONFIG_PAGECACHE     7  /* void*, int sz, int N */
2014 #define SQLITE_CONFIG_HEAP          8  /* void*, int nByte, int min */
2015 #define SQLITE_CONFIG_MEMSTATUS     9  /* boolean */
2016 #define SQLITE_CONFIG_MUTEX        10  /* sqlite3_mutex_methods* */
2017 #define SQLITE_CONFIG_GETMUTEX     11  /* sqlite3_mutex_methods* */
2018 /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */
2019 #define SQLITE_CONFIG_LOOKASIDE    13  /* int int */
2020 #define SQLITE_CONFIG_PCACHE       14  /* no-op */
2021 #define SQLITE_CONFIG_GETPCACHE    15  /* no-op */
2022 #define SQLITE_CONFIG_LOG          16  /* xFunc, void* */
2023 #define SQLITE_CONFIG_URI          17  /* int */
2024 #define SQLITE_CONFIG_PCACHE2      18  /* sqlite3_pcache_methods2* */
2025 #define SQLITE_CONFIG_GETPCACHE2   19  /* sqlite3_pcache_methods2* */
2026 #define SQLITE_CONFIG_COVERING_INDEX_SCAN 20  /* int */
2027 #define SQLITE_CONFIG_SQLLOG       21  /* xSqllog, void* */
2028 #define SQLITE_CONFIG_MMAP_SIZE    22  /* sqlite3_int64, sqlite3_int64 */
2029 #define SQLITE_CONFIG_WIN32_HEAPSIZE      23  /* int nByte */
2030 #define SQLITE_CONFIG_PCACHE_HDRSZ        24  /* int *psz */
2031 #define SQLITE_CONFIG_PMASZ               25  /* unsigned int szPma */
2032 #define SQLITE_CONFIG_STMTJRNL_SPILL      26  /* int nByte */
2033 #define SQLITE_CONFIG_SMALL_MALLOC        27  /* boolean */
2034 #define SQLITE_CONFIG_SORTERREF_SIZE      28  /* int nByte */
2035 #define SQLITE_CONFIG_MEMDB_MAXSIZE       29  /* sqlite3_int64 */
2036 
2037 /*
2038 ** CAPI3REF: Database Connection Configuration Options
2039 **
2040 ** These constants are the available integer configuration options that
2041 ** can be passed as the second argument to the [sqlite3_db_config()] interface.
2042 **
2043 ** New configuration options may be added in future releases of SQLite.
2044 ** Existing configuration options might be discontinued.  Applications
2045 ** should check the return code from [sqlite3_db_config()] to make sure that
2046 ** the call worked.  ^The [sqlite3_db_config()] interface will return a
2047 ** non-zero [error code] if a discontinued or unsupported configuration option
2048 ** is invoked.
2049 **
2050 ** <dl>
2051 ** [[SQLITE_DBCONFIG_LOOKASIDE]]
2052 ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
2053 ** <dd> ^This option takes three additional arguments that determine the
2054 ** [lookaside memory allocator] configuration for the [database connection].
2055 ** ^The first argument (the third parameter to [sqlite3_db_config()] is a
2056 ** pointer to a memory buffer to use for lookaside memory.
2057 ** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
2058 ** may be NULL in which case SQLite will allocate the
2059 ** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
2060 ** size of each lookaside buffer slot.  ^The third argument is the number of
2061 ** slots.  The size of the buffer in the first argument must be greater than
2062 ** or equal to the product of the second and third arguments.  The buffer
2063 ** must be aligned to an 8-byte boundary.  ^If the second argument to
2064 ** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
2065 ** rounded down to the next smaller multiple of 8.  ^(The lookaside memory
2066 ** configuration for a database connection can only be changed when that
2067 ** connection is not currently using lookaside memory, or in other words
2068 ** when the "current value" returned by
2069 ** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero.
2070 ** Any attempt to change the lookaside memory configuration when lookaside
2071 ** memory is in use leaves the configuration unchanged and returns
2072 ** [SQLITE_BUSY].)^</dd>
2073 **
2074 ** [[SQLITE_DBCONFIG_ENABLE_FKEY]]
2075 ** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
2076 ** <dd> ^This option is used to enable or disable the enforcement of
2077 ** [foreign key constraints].  There should be two additional arguments.
2078 ** The first argument is an integer which is 0 to disable FK enforcement,
2079 ** positive to enable FK enforcement or negative to leave FK enforcement
2080 ** unchanged.  The second parameter is a pointer to an integer into which
2081 ** is written 0 or 1 to indicate whether FK enforcement is off or on
2082 ** following this call.  The second parameter may be a NULL pointer, in
2083 ** which case the FK enforcement setting is not reported back. </dd>
2084 **
2085 ** [[SQLITE_DBCONFIG_ENABLE_TRIGGER]]
2086 ** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
2087 ** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
2088 ** There should be two additional arguments.
2089 ** The first argument is an integer which is 0 to disable triggers,
2090 ** positive to enable triggers or negative to leave the setting unchanged.
2091 ** The second parameter is a pointer to an integer into which
2092 ** is written 0 or 1 to indicate whether triggers are disabled or enabled
2093 ** following this call.  The second parameter may be a NULL pointer, in
2094 ** which case the trigger setting is not reported back. </dd>
2095 **
2096 ** [[SQLITE_DBCONFIG_ENABLE_VIEW]]
2097 ** <dt>SQLITE_DBCONFIG_ENABLE_VIEW</dt>
2098 ** <dd> ^This option is used to enable or disable [CREATE VIEW | views].
2099 ** There should be two additional arguments.
2100 ** The first argument is an integer which is 0 to disable views,
2101 ** positive to enable views or negative to leave the setting unchanged.
2102 ** The second parameter is a pointer to an integer into which
2103 ** is written 0 or 1 to indicate whether views are disabled or enabled
2104 ** following this call.  The second parameter may be a NULL pointer, in
2105 ** which case the view setting is not reported back. </dd>
2106 **
2107 ** [[SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER]]
2108 ** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt>
2109 ** <dd> ^This option is used to enable or disable the
2110 ** [fts3_tokenizer()] function which is part of the
2111 ** [FTS3] full-text search engine extension.
2112 ** There should be two additional arguments.
2113 ** The first argument is an integer which is 0 to disable fts3_tokenizer() or
2114 ** positive to enable fts3_tokenizer() or negative to leave the setting
2115 ** unchanged.
2116 ** The second parameter is a pointer to an integer into which
2117 ** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled
2118 ** following this call.  The second parameter may be a NULL pointer, in
2119 ** which case the new setting is not reported back. </dd>
2120 **
2121 ** [[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION]]
2122 ** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt>
2123 ** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()]
2124 ** interface independently of the [load_extension()] SQL function.
2125 ** The [sqlite3_enable_load_extension()] API enables or disables both the
2126 ** C-API [sqlite3_load_extension()] and the SQL function [load_extension()].
2127 ** There should be two additional arguments.
2128 ** When the first argument to this interface is 1, then only the C-API is
2129 ** enabled and the SQL function remains disabled.  If the first argument to
2130 ** this interface is 0, then both the C-API and the SQL function are disabled.
2131 ** If the first argument is -1, then no changes are made to state of either the
2132 ** C-API or the SQL function.
2133 ** The second parameter is a pointer to an integer into which
2134 ** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface
2135 ** is disabled or enabled following this call.  The second parameter may
2136 ** be a NULL pointer, in which case the new setting is not reported back.
2137 ** </dd>
2138 **
2139 ** [[SQLITE_DBCONFIG_MAINDBNAME]] <dt>SQLITE_DBCONFIG_MAINDBNAME</dt>
2140 ** <dd> ^This option is used to change the name of the "main" database
2141 ** schema.  ^The sole argument is a pointer to a constant UTF8 string
2142 ** which will become the new schema name in place of "main".  ^SQLite
2143 ** does not make a copy of the new main schema name string, so the application
2144 ** must ensure that the argument passed into this DBCONFIG option is unchanged
2145 ** until after the database connection closes.
2146 ** </dd>
2147 **
2148 ** [[SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE]]
2149 ** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt>
2150 ** <dd> Usually, when a database in wal mode is closed or detached from a
2151 ** database handle, SQLite checks if this will mean that there are now no
2152 ** connections at all to the database. If so, it performs a checkpoint
2153 ** operation before closing the connection. This option may be used to
2154 ** override this behaviour. The first parameter passed to this operation
2155 ** is an integer - positive to disable checkpoints-on-close, or zero (the
2156 ** default) to enable them, and negative to leave the setting unchanged.
2157 ** The second parameter is a pointer to an integer
2158 ** into which is written 0 or 1 to indicate whether checkpoints-on-close
2159 ** have been disabled - 0 if they are not disabled, 1 if they are.
2160 ** </dd>
2161 **
2162 ** [[SQLITE_DBCONFIG_ENABLE_QPSG]] <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt>
2163 ** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates
2164 ** the [query planner stability guarantee] (QPSG).  When the QPSG is active,
2165 ** a single SQL query statement will always use the same algorithm regardless
2166 ** of values of [bound parameters].)^ The QPSG disables some query optimizations
2167 ** that look at the values of bound parameters, which can make some queries
2168 ** slower.  But the QPSG has the advantage of more predictable behavior.  With
2169 ** the QPSG active, SQLite will always use the same query plan in the field as
2170 ** was used during testing in the lab.
2171 ** The first argument to this setting is an integer which is 0 to disable
2172 ** the QPSG, positive to enable QPSG, or negative to leave the setting
2173 ** unchanged. The second parameter is a pointer to an integer into which
2174 ** is written 0 or 1 to indicate whether the QPSG is disabled or enabled
2175 ** following this call.
2176 ** </dd>
2177 **
2178 ** [[SQLITE_DBCONFIG_TRIGGER_EQP]] <dt>SQLITE_DBCONFIG_TRIGGER_EQP</dt>
2179 ** <dd> By default, the output of EXPLAIN QUERY PLAN commands does not
2180 ** include output for any operations performed by trigger programs. This
2181 ** option is used to set or clear (the default) a flag that governs this
2182 ** behavior. The first parameter passed to this operation is an integer -
2183 ** positive to enable output for trigger programs, or zero to disable it,
2184 ** or negative to leave the setting unchanged.
2185 ** The second parameter is a pointer to an integer into which is written
2186 ** 0 or 1 to indicate whether output-for-triggers has been disabled - 0 if
2187 ** it is not disabled, 1 if it is.
2188 ** </dd>
2189 **
2190 ** [[SQLITE_DBCONFIG_RESET_DATABASE]] <dt>SQLITE_DBCONFIG_RESET_DATABASE</dt>
2191 ** <dd> Set the SQLITE_DBCONFIG_RESET_DATABASE flag and then run
2192 ** [VACUUM] in order to reset a database back to an empty database
2193 ** with no schema and no content. The following process works even for
2194 ** a badly corrupted database file:
2195 ** <ol>
2196 ** <li> If the database connection is newly opened, make sure it has read the
2197 **      database schema by preparing then discarding some query against the
2198 **      database, or calling sqlite3_table_column_metadata(), ignoring any
2199 **      errors.  This step is only necessary if the application desires to keep
2200 **      the database in WAL mode after the reset if it was in WAL mode before
2201 **      the reset.
2202 ** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 1, 0);
2203 ** <li> [sqlite3_exec](db, "[VACUUM]", 0, 0, 0);
2204 ** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 0, 0);
2205 ** </ol>
2206 ** Because resetting a database is destructive and irreversible, the
2207 ** process requires the use of this obscure API and multiple steps to help
2208 ** ensure that it does not happen by accident.
2209 **
2210 ** [[SQLITE_DBCONFIG_DEFENSIVE]] <dt>SQLITE_DBCONFIG_DEFENSIVE</dt>
2211 ** <dd>The SQLITE_DBCONFIG_DEFENSIVE option activates or deactivates the
2212 ** "defensive" flag for a database connection.  When the defensive
2213 ** flag is enabled, language features that allow ordinary SQL to
2214 ** deliberately corrupt the database file are disabled.  The disabled
2215 ** features include but are not limited to the following:
2216 ** <ul>
2217 ** <li> The [PRAGMA writable_schema=ON] statement.
2218 ** <li> The [PRAGMA journal_mode=OFF] statement.
2219 ** <li> Writes to the [sqlite_dbpage] virtual table.
2220 ** <li> Direct writes to [shadow tables].
2221 ** </ul>
2222 ** </dd>
2223 **
2224 ** [[SQLITE_DBCONFIG_WRITABLE_SCHEMA]] <dt>SQLITE_DBCONFIG_WRITABLE_SCHEMA</dt>
2225 ** <dd>The SQLITE_DBCONFIG_WRITABLE_SCHEMA option activates or deactivates the
2226 ** "writable_schema" flag. This has the same effect and is logically equivalent
2227 ** to setting [PRAGMA writable_schema=ON] or [PRAGMA writable_schema=OFF].
2228 ** The first argument to this setting is an integer which is 0 to disable
2229 ** the writable_schema, positive to enable writable_schema, or negative to
2230 ** leave the setting unchanged. The second parameter is a pointer to an
2231 ** integer into which is written 0 or 1 to indicate whether the writable_schema
2232 ** is enabled or disabled following this call.
2233 ** </dd>
2234 **
2235 ** [[SQLITE_DBCONFIG_LEGACY_ALTER_TABLE]]
2236 ** <dt>SQLITE_DBCONFIG_LEGACY_ALTER_TABLE</dt>
2237 ** <dd>The SQLITE_DBCONFIG_LEGACY_ALTER_TABLE option activates or deactivates
2238 ** the legacy behavior of the [ALTER TABLE RENAME] command such it
2239 ** behaves as it did prior to [version 3.24.0] (2018-06-04).  See the
2240 ** "Compatibility Notice" on the [ALTER TABLE RENAME documentation] for
2241 ** additional information. This feature can also be turned on and off
2242 ** using the [PRAGMA legacy_alter_table] statement.
2243 ** </dd>
2244 **
2245 ** [[SQLITE_DBCONFIG_DQS_DML]]
2246 ** <dt>SQLITE_DBCONFIG_DQS_DML</td>
2247 ** <dd>The SQLITE_DBCONFIG_DQS_DML option activates or deactivates
2248 ** the legacy [double-quoted string literal] misfeature for DML statement
2249 ** only, that is DELETE, INSERT, SELECT, and UPDATE statements. The
2250 ** default value of this setting is determined by the [-DSQLITE_DQS]
2251 ** compile-time option.
2252 ** </dd>
2253 **
2254 ** [[SQLITE_DBCONFIG_DQS_DDL]]
2255 ** <dt>SQLITE_DBCONFIG_DQS_DDL</td>
2256 ** <dd>The SQLITE_DBCONFIG_DQS option activates or deactivates
2257 ** the legacy [double-quoted string literal] misfeature for DDL statements,
2258 ** such as CREATE TABLE and CREATE INDEX. The
2259 ** default value of this setting is determined by the [-DSQLITE_DQS]
2260 ** compile-time option.
2261 ** </dd>
2262 ** </dl>
2263 */
2264 #define SQLITE_DBCONFIG_MAINDBNAME            1000 /* const char* */
2265 #define SQLITE_DBCONFIG_LOOKASIDE             1001 /* void* int int */
2266 #define SQLITE_DBCONFIG_ENABLE_FKEY           1002 /* int int* */
2267 #define SQLITE_DBCONFIG_ENABLE_TRIGGER        1003 /* int int* */
2268 #define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */
2269 #define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */
2270 #define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE      1006 /* int int* */
2271 #define SQLITE_DBCONFIG_ENABLE_QPSG           1007 /* int int* */
2272 #define SQLITE_DBCONFIG_TRIGGER_EQP           1008 /* int int* */
2273 #define SQLITE_DBCONFIG_RESET_DATABASE        1009 /* int int* */
2274 #define SQLITE_DBCONFIG_DEFENSIVE             1010 /* int int* */
2275 #define SQLITE_DBCONFIG_WRITABLE_SCHEMA       1011 /* int int* */
2276 #define SQLITE_DBCONFIG_LEGACY_ALTER_TABLE    1012 /* int int* */
2277 #define SQLITE_DBCONFIG_DQS_DML               1013 /* int int* */
2278 #define SQLITE_DBCONFIG_DQS_DDL               1014 /* int int* */
2279 #define SQLITE_DBCONFIG_ENABLE_VIEW           1015 /* int int* */
2280 #define SQLITE_DBCONFIG_MAX                   1015 /* Largest DBCONFIG */
2281 
2282 /*
2283 ** CAPI3REF: Enable Or Disable Extended Result Codes
2284 ** METHOD: sqlite3
2285 **
2286 ** ^The sqlite3_extended_result_codes() routine enables or disables the
2287 ** [extended result codes] feature of SQLite. ^The extended result
2288 ** codes are disabled by default for historical compatibility.
2289 */
2290 SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff);
2291 
2292 /*
2293 ** CAPI3REF: Last Insert Rowid
2294 ** METHOD: sqlite3
2295 **
2296 ** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables)
2297 ** has a unique 64-bit signed
2298 ** integer key called the [ROWID | "rowid"]. ^The rowid is always available
2299 ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
2300 ** names are not also used by explicitly declared columns. ^If
2301 ** the table has a column of type [INTEGER PRIMARY KEY] then that column
2302 ** is another alias for the rowid.
2303 **
2304 ** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of
2305 ** the most recent successful [INSERT] into a rowid table or [virtual table]
2306 ** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not
2307 ** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred
2308 ** on the database connection D, then sqlite3_last_insert_rowid(D) returns
2309 ** zero.
2310 **
2311 ** As well as being set automatically as rows are inserted into database
2312 ** tables, the value returned by this function may be set explicitly by
2313 ** [sqlite3_set_last_insert_rowid()]
2314 **
2315 ** Some virtual table implementations may INSERT rows into rowid tables as
2316 ** part of committing a transaction (e.g. to flush data accumulated in memory
2317 ** to disk). In this case subsequent calls to this function return the rowid
2318 ** associated with these internal INSERT operations, which leads to
2319 ** unintuitive results. Virtual table implementations that do write to rowid
2320 ** tables in this way can avoid this problem by restoring the original
2321 ** rowid value using [sqlite3_set_last_insert_rowid()] before returning
2322 ** control to the user.
2323 **
2324 ** ^(If an [INSERT] occurs within a trigger then this routine will
2325 ** return the [rowid] of the inserted row as long as the trigger is
2326 ** running. Once the trigger program ends, the value returned
2327 ** by this routine reverts to what it was before the trigger was fired.)^
2328 **
2329 ** ^An [INSERT] that fails due to a constraint violation is not a
2330 ** successful [INSERT] and does not change the value returned by this
2331 ** routine.  ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
2332 ** and INSERT OR ABORT make no changes to the return value of this
2333 ** routine when their insertion fails.  ^(When INSERT OR REPLACE
2334 ** encounters a constraint violation, it does not fail.  The
2335 ** INSERT continues to completion after deleting rows that caused
2336 ** the constraint problem so INSERT OR REPLACE will always change
2337 ** the return value of this interface.)^
2338 **
2339 ** ^For the purposes of this routine, an [INSERT] is considered to
2340 ** be successful even if it is subsequently rolled back.
2341 **
2342 ** This function is accessible to SQL statements via the
2343 ** [last_insert_rowid() SQL function].
2344 **
2345 ** If a separate thread performs a new [INSERT] on the same
2346 ** database connection while the [sqlite3_last_insert_rowid()]
2347 ** function is running and thus changes the last insert [rowid],
2348 ** then the value returned by [sqlite3_last_insert_rowid()] is
2349 ** unpredictable and might not equal either the old or the new
2350 ** last insert [rowid].
2351 */
2352 SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
2353 
2354 /*
2355 ** CAPI3REF: Set the Last Insert Rowid value.
2356 ** METHOD: sqlite3
2357 **
2358 ** The sqlite3_set_last_insert_rowid(D, R) method allows the application to
2359 ** set the value returned by calling sqlite3_last_insert_rowid(D) to R
2360 ** without inserting a row into the database.
2361 */
2362 SQLITE_API void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64);
2363 
2364 /*
2365 ** CAPI3REF: Count The Number Of Rows Modified
2366 ** METHOD: sqlite3
2367 **
2368 ** ^This function returns the number of rows modified, inserted or
2369 ** deleted by the most recently completed INSERT, UPDATE or DELETE
2370 ** statement on the database connection specified by the only parameter.
2371 ** ^Executing any other type of SQL statement does not modify the value
2372 ** returned by this function.
2373 **
2374 ** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are
2375 ** considered - auxiliary changes caused by [CREATE TRIGGER | triggers],
2376 ** [foreign key actions] or [REPLACE] constraint resolution are not counted.
2377 **
2378 ** Changes to a view that are intercepted by
2379 ** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value
2380 ** returned by sqlite3_changes() immediately after an INSERT, UPDATE or
2381 ** DELETE statement run on a view is always zero. Only changes made to real
2382 ** tables are counted.
2383 **
2384 ** Things are more complicated if the sqlite3_changes() function is
2385 ** executed while a trigger program is running. This may happen if the
2386 ** program uses the [changes() SQL function], or if some other callback
2387 ** function invokes sqlite3_changes() directly. Essentially:
2388 **
2389 ** <ul>
2390 **   <li> ^(Before entering a trigger program the value returned by
2391 **        sqlite3_changes() function is saved. After the trigger program
2392 **        has finished, the original value is restored.)^
2393 **
2394 **   <li> ^(Within a trigger program each INSERT, UPDATE and DELETE
2395 **        statement sets the value returned by sqlite3_changes()
2396 **        upon completion as normal. Of course, this value will not include
2397 **        any changes performed by sub-triggers, as the sqlite3_changes()
2398 **        value will be saved and restored after each sub-trigger has run.)^
2399 ** </ul>
2400 **
2401 ** ^This means that if the changes() SQL function (or similar) is used
2402 ** by the first INSERT, UPDATE or DELETE statement within a trigger, it
2403 ** returns the value as set when the calling statement began executing.
2404 ** ^If it is used by the second or subsequent such statement within a trigger
2405 ** program, the value returned reflects the number of rows modified by the
2406 ** previous INSERT, UPDATE or DELETE statement within the same trigger.
2407 **
2408 ** If a separate thread makes changes on the same database connection
2409 ** while [sqlite3_changes()] is running then the value returned
2410 ** is unpredictable and not meaningful.
2411 **
2412 ** See also:
2413 ** <ul>
2414 ** <li> the [sqlite3_total_changes()] interface
2415 ** <li> the [count_changes pragma]
2416 ** <li> the [changes() SQL function]
2417 ** <li> the [data_version pragma]
2418 ** </ul>
2419 */
2420 SQLITE_API int sqlite3_changes(sqlite3*);
2421 
2422 /*
2423 ** CAPI3REF: Total Number Of Rows Modified
2424 ** METHOD: sqlite3
2425 **
2426 ** ^This function returns the total number of rows inserted, modified or
2427 ** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed
2428 ** since the database connection was opened, including those executed as
2429 ** part of trigger programs. ^Executing any other type of SQL statement
2430 ** does not affect the value returned by sqlite3_total_changes().
2431 **
2432 ** ^Changes made as part of [foreign key actions] are included in the
2433 ** count, but those made as part of REPLACE constraint resolution are
2434 ** not. ^Changes to a view that are intercepted by INSTEAD OF triggers
2435 ** are not counted.
2436 **
2437 ** The [sqlite3_total_changes(D)] interface only reports the number
2438 ** of rows that changed due to SQL statement run against database
2439 ** connection D.  Any changes by other database connections are ignored.
2440 ** To detect changes against a database file from other database
2441 ** connections use the [PRAGMA data_version] command or the
2442 ** [SQLITE_FCNTL_DATA_VERSION] [file control].
2443 **
2444 ** If a separate thread makes changes on the same database connection
2445 ** while [sqlite3_total_changes()] is running then the value
2446 ** returned is unpredictable and not meaningful.
2447 **
2448 ** See also:
2449 ** <ul>
2450 ** <li> the [sqlite3_changes()] interface
2451 ** <li> the [count_changes pragma]
2452 ** <li> the [changes() SQL function]
2453 ** <li> the [data_version pragma]
2454 ** <li> the [SQLITE_FCNTL_DATA_VERSION] [file control]
2455 ** </ul>
2456 */
2457 SQLITE_API int sqlite3_total_changes(sqlite3*);
2458 
2459 /*
2460 ** CAPI3REF: Interrupt A Long-Running Query
2461 ** METHOD: sqlite3
2462 **
2463 ** ^This function causes any pending database operation to abort and
2464 ** return at its earliest opportunity. This routine is typically
2465 ** called in response to a user action such as pressing "Cancel"
2466 ** or Ctrl-C where the user wants a long query operation to halt
2467 ** immediately.
2468 **
2469 ** ^It is safe to call this routine from a thread different from the
2470 ** thread that is currently running the database operation.  But it
2471 ** is not safe to call this routine with a [database connection] that
2472 ** is closed or might close before sqlite3_interrupt() returns.
2473 **
2474 ** ^If an SQL operation is very nearly finished at the time when
2475 ** sqlite3_interrupt() is called, then it might not have an opportunity
2476 ** to be interrupted and might continue to completion.
2477 **
2478 ** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
2479 ** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
2480 ** that is inside an explicit transaction, then the entire transaction
2481 ** will be rolled back automatically.
2482 **
2483 ** ^The sqlite3_interrupt(D) call is in effect until all currently running
2484 ** SQL statements on [database connection] D complete.  ^Any new SQL statements
2485 ** that are started after the sqlite3_interrupt() call and before the
2486 ** running statements reaches zero are interrupted as if they had been
2487 ** running prior to the sqlite3_interrupt() call.  ^New SQL statements
2488 ** that are started after the running statement count reaches zero are
2489 ** not effected by the sqlite3_interrupt().
2490 ** ^A call to sqlite3_interrupt(D) that occurs when there are no running
2491 ** SQL statements is a no-op and has no effect on SQL statements
2492 ** that are started after the sqlite3_interrupt() call returns.
2493 */
2494 SQLITE_API void sqlite3_interrupt(sqlite3*);
2495 
2496 /*
2497 ** CAPI3REF: Determine If An SQL Statement Is Complete
2498 **
2499 ** These routines are useful during command-line input to determine if the
2500 ** currently entered text seems to form a complete SQL statement or
2501 ** if additional input is needed before sending the text into
2502 ** SQLite for parsing.  ^These routines return 1 if the input string
2503 ** appears to be a complete SQL statement.  ^A statement is judged to be
2504 ** complete if it ends with a semicolon token and is not a prefix of a
2505 ** well-formed CREATE TRIGGER statement.  ^Semicolons that are embedded within
2506 ** string literals or quoted identifier names or comments are not
2507 ** independent tokens (they are part of the token in which they are
2508 ** embedded) and thus do not count as a statement terminator.  ^Whitespace
2509 ** and comments that follow the final semicolon are ignored.
2510 **
2511 ** ^These routines return 0 if the statement is incomplete.  ^If a
2512 ** memory allocation fails, then SQLITE_NOMEM is returned.
2513 **
2514 ** ^These routines do not parse the SQL statements thus
2515 ** will not detect syntactically incorrect SQL.
2516 **
2517 ** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior
2518 ** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
2519 ** automatically by sqlite3_complete16().  If that initialization fails,
2520 ** then the return value from sqlite3_complete16() will be non-zero
2521 ** regardless of whether or not the input SQL is complete.)^
2522 **
2523 ** The input to [sqlite3_complete()] must be a zero-terminated
2524 ** UTF-8 string.
2525 **
2526 ** The input to [sqlite3_complete16()] must be a zero-terminated
2527 ** UTF-16 string in native byte order.
2528 */
2529 SQLITE_API int sqlite3_complete(const char *sql);
2530 SQLITE_API int sqlite3_complete16(const void *sql);
2531 
2532 /*
2533 ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
2534 ** KEYWORDS: {busy-handler callback} {busy handler}
2535 ** METHOD: sqlite3
2536 **
2537 ** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X
2538 ** that might be invoked with argument P whenever
2539 ** an attempt is made to access a database table associated with
2540 ** [database connection] D when another thread
2541 ** or process has the table locked.
2542 ** The sqlite3_busy_handler() interface is used to implement
2543 ** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout].
2544 **
2545 ** ^If the busy callback is NULL, then [SQLITE_BUSY]
2546 ** is returned immediately upon encountering the lock.  ^If the busy callback
2547 ** is not NULL, then the callback might be invoked with two arguments.
2548 **
2549 ** ^The first argument to the busy handler is a copy of the void* pointer which
2550 ** is the third argument to sqlite3_busy_handler().  ^The second argument to
2551 ** the busy handler callback is the number of times that the busy handler has
2552 ** been invoked previously for the same locking event.  ^If the
2553 ** busy callback returns 0, then no additional attempts are made to
2554 ** access the database and [SQLITE_BUSY] is returned
2555 ** to the application.
2556 ** ^If the callback returns non-zero, then another attempt
2557 ** is made to access the database and the cycle repeats.
2558 **
2559 ** The presence of a busy handler does not guarantee that it will be invoked
2560 ** when there is lock contention. ^If SQLite determines that invoking the busy
2561 ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
2562 ** to the application instead of invoking the
2563 ** busy handler.
2564 ** Consider a scenario where one process is holding a read lock that
2565 ** it is trying to promote to a reserved lock and
2566 ** a second process is holding a reserved lock that it is trying
2567 ** to promote to an exclusive lock.  The first process cannot proceed
2568 ** because it is blocked by the second and the second process cannot
2569 ** proceed because it is blocked by the first.  If both processes
2570 ** invoke the busy handlers, neither will make any progress.  Therefore,
2571 ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
2572 ** will induce the first process to release its read lock and allow
2573 ** the second process to proceed.
2574 **
2575 ** ^The default busy callback is NULL.
2576 **
2577 ** ^(There can only be a single busy handler defined for each
2578 ** [database connection].  Setting a new busy handler clears any
2579 ** previously set handler.)^  ^Note that calling [sqlite3_busy_timeout()]
2580 ** or evaluating [PRAGMA busy_timeout=N] will change the
2581 ** busy handler and thus clear any previously set busy handler.
2582 **
2583 ** The busy callback should not take any actions which modify the
2584 ** database connection that invoked the busy handler.  In other words,
2585 ** the busy handler is not reentrant.  Any such actions
2586 ** result in undefined behavior.
2587 **
2588 ** A busy handler must not close the database connection
2589 ** or [prepared statement] that invoked the busy handler.
2590 */
2591 SQLITE_API int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*);
2592 
2593 /*
2594 ** CAPI3REF: Set A Busy Timeout
2595 ** METHOD: sqlite3
2596 **
2597 ** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
2598 ** for a specified amount of time when a table is locked.  ^The handler
2599 ** will sleep multiple times until at least "ms" milliseconds of sleeping
2600 ** have accumulated.  ^After at least "ms" milliseconds of sleeping,
2601 ** the handler returns 0 which causes [sqlite3_step()] to return
2602 ** [SQLITE_BUSY].
2603 **
2604 ** ^Calling this routine with an argument less than or equal to zero
2605 ** turns off all busy handlers.
2606 **
2607 ** ^(There can only be a single busy handler for a particular
2608 ** [database connection] at any given moment.  If another busy handler
2609 ** was defined  (using [sqlite3_busy_handler()]) prior to calling
2610 ** this routine, that other busy handler is cleared.)^
2611 **
2612 ** See also:  [PRAGMA busy_timeout]
2613 */
2614 SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms);
2615 
2616 /*
2617 ** CAPI3REF: Convenience Routines For Running Queries
2618 ** METHOD: sqlite3
2619 **
2620 ** This is a legacy interface that is preserved for backwards compatibility.
2621 ** Use of this interface is not recommended.
2622 **
2623 ** Definition: A <b>result table</b> is memory data structure created by the
2624 ** [sqlite3_get_table()] interface.  A result table records the
2625 ** complete query results from one or more queries.
2626 **
2627 ** The table conceptually has a number of rows and columns.  But
2628 ** these numbers are not part of the result table itself.  These
2629 ** numbers are obtained separately.  Let N be the number of rows
2630 ** and M be the number of columns.
2631 **
2632 ** A result table is an array of pointers to zero-terminated UTF-8 strings.
2633 ** There are (N+1)*M elements in the array.  The first M pointers point
2634 ** to zero-terminated strings that  contain the names of the columns.
2635 ** The remaining entries all point to query results.  NULL values result
2636 ** in NULL pointers.  All other values are in their UTF-8 zero-terminated
2637 ** string representation as returned by [sqlite3_column_text()].
2638 **
2639 ** A result table might consist of one or more memory allocations.
2640 ** It is not safe to pass a result table directly to [sqlite3_free()].
2641 ** A result table should be deallocated using [sqlite3_free_table()].
2642 **
2643 ** ^(As an example of the result table format, suppose a query result
2644 ** is as follows:
2645 **
2646 ** <blockquote><pre>
2647 **        Name        | Age
2648 **        -----------------------
2649 **        Alice       | 43
2650 **        Bob         | 28
2651 **        Cindy       | 21
2652 ** </pre></blockquote>
2653 **
2654 ** There are two column (M==2) and three rows (N==3).  Thus the
2655 ** result table has 8 entries.  Suppose the result table is stored
2656 ** in an array names azResult.  Then azResult holds this content:
2657 **
2658 ** <blockquote><pre>
2659 **        azResult&#91;0] = "Name";
2660 **        azResult&#91;1] = "Age";
2661 **        azResult&#91;2] = "Alice";
2662 **        azResult&#91;3] = "43";
2663 **        azResult&#91;4] = "Bob";
2664 **        azResult&#91;5] = "28";
2665 **        azResult&#91;6] = "Cindy";
2666 **        azResult&#91;7] = "21";
2667 ** </pre></blockquote>)^
2668 **
2669 ** ^The sqlite3_get_table() function evaluates one or more
2670 ** semicolon-separated SQL statements in the zero-terminated UTF-8
2671 ** string of its 2nd parameter and returns a result table to the
2672 ** pointer given in its 3rd parameter.
2673 **
2674 ** After the application has finished with the result from sqlite3_get_table(),
2675 ** it must pass the result table pointer to sqlite3_free_table() in order to
2676 ** release the memory that was malloced.  Because of the way the
2677 ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
2678 ** function must not try to call [sqlite3_free()] directly.  Only
2679 ** [sqlite3_free_table()] is able to release the memory properly and safely.
2680 **
2681 ** The sqlite3_get_table() interface is implemented as a wrapper around
2682 ** [sqlite3_exec()].  The sqlite3_get_table() routine does not have access
2683 ** to any internal data structures of SQLite.  It uses only the public
2684 ** interface defined here.  As a consequence, errors that occur in the
2685 ** wrapper layer outside of the internal [sqlite3_exec()] call are not
2686 ** reflected in subsequent calls to [sqlite3_errcode()] or
2687 ** [sqlite3_errmsg()].
2688 */
2689 SQLITE_API int sqlite3_get_table(
2690   sqlite3 *db,          /* An open database */
2691   const char *zSql,     /* SQL to be evaluated */
2692   char ***pazResult,    /* Results of the query */
2693   int *pnRow,           /* Number of result rows written here */
2694   int *pnColumn,        /* Number of result columns written here */
2695   char **pzErrmsg       /* Error msg written here */
2696 );
2697 SQLITE_API void sqlite3_free_table(char **result);
2698 
2699 /*
2700 ** CAPI3REF: Formatted String Printing Functions
2701 **
2702 ** These routines are work-alikes of the "printf()" family of functions
2703 ** from the standard C library.
2704 ** These routines understand most of the common formatting options from
2705 ** the standard library printf()
2706 ** plus some additional non-standard formats ([%q], [%Q], [%w], and [%z]).
2707 ** See the [built-in printf()] documentation for details.
2708 **
2709 ** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
2710 ** results into memory obtained from [sqlite3_malloc64()].
2711 ** The strings returned by these two routines should be
2712 ** released by [sqlite3_free()].  ^Both routines return a
2713 ** NULL pointer if [sqlite3_malloc64()] is unable to allocate enough
2714 ** memory to hold the resulting string.
2715 **
2716 ** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
2717 ** the standard C library.  The result is written into the
2718 ** buffer supplied as the second parameter whose size is given by
2719 ** the first parameter. Note that the order of the
2720 ** first two parameters is reversed from snprintf().)^  This is an
2721 ** historical accident that cannot be fixed without breaking
2722 ** backwards compatibility.  ^(Note also that sqlite3_snprintf()
2723 ** returns a pointer to its buffer instead of the number of
2724 ** characters actually written into the buffer.)^  We admit that
2725 ** the number of characters written would be a more useful return
2726 ** value but we cannot change the implementation of sqlite3_snprintf()
2727 ** now without breaking compatibility.
2728 **
2729 ** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
2730 ** guarantees that the buffer is always zero-terminated.  ^The first
2731 ** parameter "n" is the total size of the buffer, including space for
2732 ** the zero terminator.  So the longest string that can be completely
2733 ** written will be n-1 characters.
2734 **
2735 ** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
2736 **
2737 ** See also:  [built-in printf()], [printf() SQL function]
2738 */
2739 SQLITE_API char *sqlite3_mprintf(const char*,...);
2740 SQLITE_API char *sqlite3_vmprintf(const char*, va_list);
2741 SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...);
2742 SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list);
2743 
2744 /*
2745 ** CAPI3REF: Memory Allocation Subsystem
2746 **
2747 ** The SQLite core uses these three routines for all of its own
2748 ** internal memory allocation needs. "Core" in the previous sentence
2749 ** does not include operating-system specific VFS implementation.  The
2750 ** Windows VFS uses native malloc() and free() for some operations.
2751 **
2752 ** ^The sqlite3_malloc() routine returns a pointer to a block
2753 ** of memory at least N bytes in length, where N is the parameter.
2754 ** ^If sqlite3_malloc() is unable to obtain sufficient free
2755 ** memory, it returns a NULL pointer.  ^If the parameter N to
2756 ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
2757 ** a NULL pointer.
2758 **
2759 ** ^The sqlite3_malloc64(N) routine works just like
2760 ** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead
2761 ** of a signed 32-bit integer.
2762 **
2763 ** ^Calling sqlite3_free() with a pointer previously returned
2764 ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
2765 ** that it might be reused.  ^The sqlite3_free() routine is
2766 ** a no-op if is called with a NULL pointer.  Passing a NULL pointer
2767 ** to sqlite3_free() is harmless.  After being freed, memory
2768 ** should neither be read nor written.  Even reading previously freed
2769 ** memory might result in a segmentation fault or other severe error.
2770 ** Memory corruption, a segmentation fault, or other severe error
2771 ** might result if sqlite3_free() is called with a non-NULL pointer that
2772 ** was not obtained from sqlite3_malloc() or sqlite3_realloc().
2773 **
2774 ** ^The sqlite3_realloc(X,N) interface attempts to resize a
2775 ** prior memory allocation X to be at least N bytes.
2776 ** ^If the X parameter to sqlite3_realloc(X,N)
2777 ** is a NULL pointer then its behavior is identical to calling
2778 ** sqlite3_malloc(N).
2779 ** ^If the N parameter to sqlite3_realloc(X,N) is zero or
2780 ** negative then the behavior is exactly the same as calling
2781 ** sqlite3_free(X).
2782 ** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation
2783 ** of at least N bytes in size or NULL if insufficient memory is available.
2784 ** ^If M is the size of the prior allocation, then min(N,M) bytes
2785 ** of the prior allocation are copied into the beginning of buffer returned
2786 ** by sqlite3_realloc(X,N) and the prior allocation is freed.
2787 ** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the
2788 ** prior allocation is not freed.
2789 **
2790 ** ^The sqlite3_realloc64(X,N) interfaces works the same as
2791 ** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead
2792 ** of a 32-bit signed integer.
2793 **
2794 ** ^If X is a memory allocation previously obtained from sqlite3_malloc(),
2795 ** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then
2796 ** sqlite3_msize(X) returns the size of that memory allocation in bytes.
2797 ** ^The value returned by sqlite3_msize(X) might be larger than the number
2798 ** of bytes requested when X was allocated.  ^If X is a NULL pointer then
2799 ** sqlite3_msize(X) returns zero.  If X points to something that is not
2800 ** the beginning of memory allocation, or if it points to a formerly
2801 ** valid memory allocation that has now been freed, then the behavior
2802 ** of sqlite3_msize(X) is undefined and possibly harmful.
2803 **
2804 ** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(),
2805 ** sqlite3_malloc64(), and sqlite3_realloc64()
2806 ** is always aligned to at least an 8 byte boundary, or to a
2807 ** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
2808 ** option is used.
2809 **
2810 ** In SQLite version 3.5.0 and 3.5.1, it was possible to define
2811 ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in
2812 ** implementation of these routines to be omitted.  That capability
2813 ** is no longer provided.  Only built-in memory allocators can be used.
2814 **
2815 ** Prior to SQLite version 3.7.10, the Windows OS interface layer called
2816 ** the system malloc() and free() directly when converting
2817 ** filenames between the UTF-8 encoding used by SQLite
2818 ** and whatever filename encoding is used by the particular Windows
2819 ** installation.  Memory allocation errors were detected, but
2820 ** they were reported back as [SQLITE_CANTOPEN] or
2821 ** [SQLITE_IOERR] rather than [SQLITE_NOMEM].
2822 **
2823 ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
2824 ** must be either NULL or else pointers obtained from a prior
2825 ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
2826 ** not yet been released.
2827 **
2828 ** The application must not read or write any part of
2829 ** a block of memory after it has been released using
2830 ** [sqlite3_free()] or [sqlite3_realloc()].
2831 */
2832 SQLITE_API void *sqlite3_malloc(int);
2833 SQLITE_API void *sqlite3_malloc64(sqlite3_uint64);
2834 SQLITE_API void *sqlite3_realloc(void*, int);
2835 SQLITE_API void *sqlite3_realloc64(void*, sqlite3_uint64);
2836 SQLITE_API void sqlite3_free(void*);
2837 SQLITE_API sqlite3_uint64 sqlite3_msize(void*);
2838 
2839 /*
2840 ** CAPI3REF: Memory Allocator Statistics
2841 **
2842 ** SQLite provides these two interfaces for reporting on the status
2843 ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
2844 ** routines, which form the built-in memory allocation subsystem.
2845 **
2846 ** ^The [sqlite3_memory_used()] routine returns the number of bytes
2847 ** of memory currently outstanding (malloced but not freed).
2848 ** ^The [sqlite3_memory_highwater()] routine returns the maximum
2849 ** value of [sqlite3_memory_used()] since the high-water mark
2850 ** was last reset.  ^The values returned by [sqlite3_memory_used()] and
2851 ** [sqlite3_memory_highwater()] include any overhead
2852 ** added by SQLite in its implementation of [sqlite3_malloc()],
2853 ** but not overhead added by the any underlying system library
2854 ** routines that [sqlite3_malloc()] may call.
2855 **
2856 ** ^The memory high-water mark is reset to the current value of
2857 ** [sqlite3_memory_used()] if and only if the parameter to
2858 ** [sqlite3_memory_highwater()] is true.  ^The value returned
2859 ** by [sqlite3_memory_highwater(1)] is the high-water mark
2860 ** prior to the reset.
2861 */
2862 SQLITE_API sqlite3_int64 sqlite3_memory_used(void);
2863 SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
2864 
2865 /*
2866 ** CAPI3REF: Pseudo-Random Number Generator
2867 **
2868 ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
2869 ** select random [ROWID | ROWIDs] when inserting new records into a table that
2870 ** already uses the largest possible [ROWID].  The PRNG is also used for
2871 ** the build-in random() and randomblob() SQL functions.  This interface allows
2872 ** applications to access the same PRNG for other purposes.
2873 **
2874 ** ^A call to this routine stores N bytes of randomness into buffer P.
2875 ** ^The P parameter can be a NULL pointer.
2876 **
2877 ** ^If this routine has not been previously called or if the previous
2878 ** call had N less than one or a NULL pointer for P, then the PRNG is
2879 ** seeded using randomness obtained from the xRandomness method of
2880 ** the default [sqlite3_vfs] object.
2881 ** ^If the previous call to this routine had an N of 1 or more and a
2882 ** non-NULL P then the pseudo-randomness is generated
2883 ** internally and without recourse to the [sqlite3_vfs] xRandomness
2884 ** method.
2885 */
2886 SQLITE_API void sqlite3_randomness(int N, void *P);
2887 
2888 /*
2889 ** CAPI3REF: Compile-Time Authorization Callbacks
2890 ** METHOD: sqlite3
2891 ** KEYWORDS: {authorizer callback}
2892 **
2893 ** ^This routine registers an authorizer callback with a particular
2894 ** [database connection], supplied in the first argument.
2895 ** ^The authorizer callback is invoked as SQL statements are being compiled
2896 ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
2897 ** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()],
2898 ** and [sqlite3_prepare16_v3()].  ^At various
2899 ** points during the compilation process, as logic is being created
2900 ** to perform various actions, the authorizer callback is invoked to
2901 ** see if those actions are allowed.  ^The authorizer callback should
2902 ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
2903 ** specific action but allow the SQL statement to continue to be
2904 ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
2905 ** rejected with an error.  ^If the authorizer callback returns
2906 ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
2907 ** then the [sqlite3_prepare_v2()] or equivalent call that triggered
2908 ** the authorizer will fail with an error message.
2909 **
2910 ** When the callback returns [SQLITE_OK], that means the operation
2911 ** requested is ok.  ^When the callback returns [SQLITE_DENY], the
2912 ** [sqlite3_prepare_v2()] or equivalent call that triggered the
2913 ** authorizer will fail with an error message explaining that
2914 ** access is denied.
2915 **
2916 ** ^The first parameter to the authorizer callback is a copy of the third
2917 ** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
2918 ** to the callback is an integer [SQLITE_COPY | action code] that specifies
2919 ** the particular action to be authorized. ^The third through sixth parameters
2920 ** to the callback are either NULL pointers or zero-terminated strings
2921 ** that contain additional details about the action to be authorized.
2922 ** Applications must always be prepared to encounter a NULL pointer in any
2923 ** of the third through the sixth parameters of the authorization callback.
2924 **
2925 ** ^If the action code is [SQLITE_READ]
2926 ** and the callback returns [SQLITE_IGNORE] then the
2927 ** [prepared statement] statement is constructed to substitute
2928 ** a NULL value in place of the table column that would have
2929 ** been read if [SQLITE_OK] had been returned.  The [SQLITE_IGNORE]
2930 ** return can be used to deny an untrusted user access to individual
2931 ** columns of a table.
2932 ** ^When a table is referenced by a [SELECT] but no column values are
2933 ** extracted from that table (for example in a query like
2934 ** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback
2935 ** is invoked once for that table with a column name that is an empty string.
2936 ** ^If the action code is [SQLITE_DELETE] and the callback returns
2937 ** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
2938 ** [truncate optimization] is disabled and all rows are deleted individually.
2939 **
2940 ** An authorizer is used when [sqlite3_prepare | preparing]
2941 ** SQL statements from an untrusted source, to ensure that the SQL statements
2942 ** do not try to access data they are not allowed to see, or that they do not
2943 ** try to execute malicious statements that damage the database.  For
2944 ** example, an application may allow a user to enter arbitrary
2945 ** SQL queries for evaluation by a database.  But the application does
2946 ** not want the user to be able to make arbitrary changes to the
2947 ** database.  An authorizer could then be put in place while the
2948 ** user-entered SQL is being [sqlite3_prepare | prepared] that
2949 ** disallows everything except [SELECT] statements.
2950 **
2951 ** Applications that need to process SQL from untrusted sources
2952 ** might also consider lowering resource limits using [sqlite3_limit()]
2953 ** and limiting database size using the [max_page_count] [PRAGMA]
2954 ** in addition to using an authorizer.
2955 **
2956 ** ^(Only a single authorizer can be in place on a database connection
2957 ** at a time.  Each call to sqlite3_set_authorizer overrides the
2958 ** previous call.)^  ^Disable the authorizer by installing a NULL callback.
2959 ** The authorizer is disabled by default.
2960 **
2961 ** The authorizer callback must not do anything that will modify
2962 ** the database connection that invoked the authorizer callback.
2963 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2964 ** database connections for the meaning of "modify" in this paragraph.
2965 **
2966 ** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
2967 ** statement might be re-prepared during [sqlite3_step()] due to a
2968 ** schema change.  Hence, the application should ensure that the
2969 ** correct authorizer callback remains in place during the [sqlite3_step()].
2970 **
2971 ** ^Note that the authorizer callback is invoked only during
2972 ** [sqlite3_prepare()] or its variants.  Authorization is not
2973 ** performed during statement evaluation in [sqlite3_step()], unless
2974 ** as stated in the previous paragraph, sqlite3_step() invokes
2975 ** sqlite3_prepare_v2() to reprepare a statement after a schema change.
2976 */
2977 SQLITE_API int sqlite3_set_authorizer(
2978   sqlite3*,
2979   int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
2980   void *pUserData
2981 );
2982 
2983 /*
2984 ** CAPI3REF: Authorizer Return Codes
2985 **
2986 ** The [sqlite3_set_authorizer | authorizer callback function] must
2987 ** return either [SQLITE_OK] or one of these two constants in order
2988 ** to signal SQLite whether or not the action is permitted.  See the
2989 ** [sqlite3_set_authorizer | authorizer documentation] for additional
2990 ** information.
2991 **
2992 ** Note that SQLITE_IGNORE is also used as a [conflict resolution mode]
2993 ** returned from the [sqlite3_vtab_on_conflict()] interface.
2994 */
2995 #define SQLITE_DENY   1   /* Abort the SQL statement with an error */
2996 #define SQLITE_IGNORE 2   /* Don't allow access, but don't generate an error */
2997 
2998 /*
2999 ** CAPI3REF: Authorizer Action Codes
3000 **
3001 ** The [sqlite3_set_authorizer()] interface registers a callback function
3002 ** that is invoked to authorize certain SQL statement actions.  The
3003 ** second parameter to the callback is an integer code that specifies
3004 ** what action is being authorized.  These are the integer action codes that
3005 ** the authorizer callback may be passed.
3006 **
3007 ** These action code values signify what kind of operation is to be
3008 ** authorized.  The 3rd and 4th parameters to the authorization
3009 ** callback function will be parameters or NULL depending on which of these
3010 ** codes is used as the second parameter.  ^(The 5th parameter to the
3011 ** authorizer callback is the name of the database ("main", "temp",
3012 ** etc.) if applicable.)^  ^The 6th parameter to the authorizer callback
3013 ** is the name of the inner-most trigger or view that is responsible for
3014 ** the access attempt or NULL if this access attempt is directly from
3015 ** top-level SQL code.
3016 */
3017 /******************************************* 3rd ************ 4th ***********/
3018 #define SQLITE_CREATE_INDEX          1   /* Index Name      Table Name      */
3019 #define SQLITE_CREATE_TABLE          2   /* Table Name      NULL            */
3020 #define SQLITE_CREATE_TEMP_INDEX     3   /* Index Name      Table Name      */
3021 #define SQLITE_CREATE_TEMP_TABLE     4   /* Table Name      NULL            */
3022 #define SQLITE_CREATE_TEMP_TRIGGER   5   /* Trigger Name    Table Name      */
3023 #define SQLITE_CREATE_TEMP_VIEW      6   /* View Name       NULL            */
3024 #define SQLITE_CREATE_TRIGGER        7   /* Trigger Name    Table Name      */
3025 #define SQLITE_CREATE_VIEW           8   /* View Name       NULL            */
3026 #define SQLITE_DELETE                9   /* Table Name      NULL            */
3027 #define SQLITE_DROP_INDEX           10   /* Index Name      Table Name      */
3028 #define SQLITE_DROP_TABLE           11   /* Table Name      NULL            */
3029 #define SQLITE_DROP_TEMP_INDEX      12   /* Index Name      Table Name      */
3030 #define SQLITE_DROP_TEMP_TABLE      13   /* Table Name      NULL            */
3031 #define SQLITE_DROP_TEMP_TRIGGER    14   /* Trigger Name    Table Name      */
3032 #define SQLITE_DROP_TEMP_VIEW       15   /* View Name       NULL            */
3033 #define SQLITE_DROP_TRIGGER         16   /* Trigger Name    Table Name      */
3034 #define SQLITE_DROP_VIEW            17   /* View Name       NULL            */
3035 #define SQLITE_INSERT               18   /* Table Name      NULL            */
3036 #define SQLITE_PRAGMA               19   /* Pragma Name     1st arg or NULL */
3037 #define SQLITE_READ                 20   /* Table Name      Column Name     */
3038 #define SQLITE_SELECT               21   /* NULL            NULL            */
3039 #define SQLITE_TRANSACTION          22   /* Operation       NULL            */
3040 #define SQLITE_UPDATE               23   /* Table Name      Column Name     */
3041 #define SQLITE_ATTACH               24   /* Filename        NULL            */
3042 #define SQLITE_DETACH               25   /* Database Name   NULL            */
3043 #define SQLITE_ALTER_TABLE          26   /* Database Name   Table Name      */
3044 #define SQLITE_REINDEX              27   /* Index Name      NULL            */
3045 #define SQLITE_ANALYZE              28   /* Table Name      NULL            */
3046 #define SQLITE_CREATE_VTABLE        29   /* Table Name      Module Name     */
3047 #define SQLITE_DROP_VTABLE          30   /* Table Name      Module Name     */
3048 #define SQLITE_FUNCTION             31   /* NULL            Function Name   */
3049 #define SQLITE_SAVEPOINT            32   /* Operation       Savepoint Name  */
3050 #define SQLITE_COPY                  0   /* No longer used */
3051 #define SQLITE_RECURSIVE            33   /* NULL            NULL            */
3052 
3053 /*
3054 ** CAPI3REF: Tracing And Profiling Functions
3055 ** METHOD: sqlite3
3056 **
3057 ** These routines are deprecated. Use the [sqlite3_trace_v2()] interface
3058 ** instead of the routines described here.
3059 **
3060 ** These routines register callback functions that can be used for
3061 ** tracing and profiling the execution of SQL statements.
3062 **
3063 ** ^The callback function registered by sqlite3_trace() is invoked at
3064 ** various times when an SQL statement is being run by [sqlite3_step()].
3065 ** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
3066 ** SQL statement text as the statement first begins executing.
3067 ** ^(Additional sqlite3_trace() callbacks might occur
3068 ** as each triggered subprogram is entered.  The callbacks for triggers
3069 ** contain a UTF-8 SQL comment that identifies the trigger.)^
3070 **
3071 ** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit
3072 ** the length of [bound parameter] expansion in the output of sqlite3_trace().
3073 **
3074 ** ^The callback function registered by sqlite3_profile() is invoked
3075 ** as each SQL statement finishes.  ^The profile callback contains
3076 ** the original statement text and an estimate of wall-clock time
3077 ** of how long that statement took to run.  ^The profile callback
3078 ** time is in units of nanoseconds, however the current implementation
3079 ** is only capable of millisecond resolution so the six least significant
3080 ** digits in the time are meaningless.  Future versions of SQLite
3081 ** might provide greater resolution on the profiler callback.  Invoking
3082 ** either [sqlite3_trace()] or [sqlite3_trace_v2()] will cancel the
3083 ** profile callback.
3084 */
3085 SQLITE_API SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*,
3086    void(*xTrace)(void*,const char*), void*);
3087 SQLITE_API SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*,
3088    void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
3089 
3090 /*
3091 ** CAPI3REF: SQL Trace Event Codes
3092 ** KEYWORDS: SQLITE_TRACE
3093 **
3094 ** These constants identify classes of events that can be monitored
3095 ** using the [sqlite3_trace_v2()] tracing logic.  The M argument
3096 ** to [sqlite3_trace_v2(D,M,X,P)] is an OR-ed combination of one or more of
3097 ** the following constants.  ^The first argument to the trace callback
3098 ** is one of the following constants.
3099 **
3100 ** New tracing constants may be added in future releases.
3101 **
3102 ** ^A trace callback has four arguments: xCallback(T,C,P,X).
3103 ** ^The T argument is one of the integer type codes above.
3104 ** ^The C argument is a copy of the context pointer passed in as the
3105 ** fourth argument to [sqlite3_trace_v2()].
3106 ** The P and X arguments are pointers whose meanings depend on T.
3107 **
3108 ** <dl>
3109 ** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt>
3110 ** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement
3111 ** first begins running and possibly at other times during the
3112 ** execution of the prepared statement, such as at the start of each
3113 ** trigger subprogram. ^The P argument is a pointer to the
3114 ** [prepared statement]. ^The X argument is a pointer to a string which
3115 ** is the unexpanded SQL text of the prepared statement or an SQL comment
3116 ** that indicates the invocation of a trigger.  ^The callback can compute
3117 ** the same text that would have been returned by the legacy [sqlite3_trace()]
3118 ** interface by using the X argument when X begins with "--" and invoking
3119 ** [sqlite3_expanded_sql(P)] otherwise.
3120 **
3121 ** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt>
3122 ** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same
3123 ** information as is provided by the [sqlite3_profile()] callback.
3124 ** ^The P argument is a pointer to the [prepared statement] and the
3125 ** X argument points to a 64-bit integer which is the estimated of
3126 ** the number of nanosecond that the prepared statement took to run.
3127 ** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes.
3128 **
3129 ** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt>
3130 ** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared
3131 ** statement generates a single row of result.
3132 ** ^The P argument is a pointer to the [prepared statement] and the
3133 ** X argument is unused.
3134 **
3135 ** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt>
3136 ** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database
3137 ** connection closes.
3138 ** ^The P argument is a pointer to the [database connection] object
3139 ** and the X argument is unused.
3140 ** </dl>
3141 */
3142 #define SQLITE_TRACE_STMT       0x01
3143 #define SQLITE_TRACE_PROFILE    0x02
3144 #define SQLITE_TRACE_ROW        0x04
3145 #define SQLITE_TRACE_CLOSE      0x08
3146 
3147 /*
3148 ** CAPI3REF: SQL Trace Hook
3149 ** METHOD: sqlite3
3150 **
3151 ** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback
3152 ** function X against [database connection] D, using property mask M
3153 ** and context pointer P.  ^If the X callback is
3154 ** NULL or if the M mask is zero, then tracing is disabled.  The
3155 ** M argument should be the bitwise OR-ed combination of
3156 ** zero or more [SQLITE_TRACE] constants.
3157 **
3158 ** ^Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides
3159 ** (cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2().
3160 **
3161 ** ^The X callback is invoked whenever any of the events identified by
3162 ** mask M occur.  ^The integer return value from the callback is currently
3163 ** ignored, though this may change in future releases.  Callback
3164 ** implementations should return zero to ensure future compatibility.
3165 **
3166 ** ^A trace callback is invoked with four arguments: callback(T,C,P,X).
3167 ** ^The T argument is one of the [SQLITE_TRACE]
3168 ** constants to indicate why the callback was invoked.
3169 ** ^The C argument is a copy of the context pointer.
3170 ** The P and X arguments are pointers whose meanings depend on T.
3171 **
3172 ** The sqlite3_trace_v2() interface is intended to replace the legacy
3173 ** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which
3174 ** are deprecated.
3175 */
3176 SQLITE_API int sqlite3_trace_v2(
3177   sqlite3*,
3178   unsigned uMask,
3179   int(*xCallback)(unsigned,void*,void*,void*),
3180   void *pCtx
3181 );
3182 
3183 /*
3184 ** CAPI3REF: Query Progress Callbacks
3185 ** METHOD: sqlite3
3186 **
3187 ** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
3188 ** function X to be invoked periodically during long running calls to
3189 ** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for
3190 ** database connection D.  An example use for this
3191 ** interface is to keep a GUI updated during a large query.
3192 **
3193 ** ^The parameter P is passed through as the only parameter to the
3194 ** callback function X.  ^The parameter N is the approximate number of
3195 ** [virtual machine instructions] that are evaluated between successive
3196 ** invocations of the callback X.  ^If N is less than one then the progress
3197 ** handler is disabled.
3198 **
3199 ** ^Only a single progress handler may be defined at one time per
3200 ** [database connection]; setting a new progress handler cancels the
3201 ** old one.  ^Setting parameter X to NULL disables the progress handler.
3202 ** ^The progress handler is also disabled by setting N to a value less
3203 ** than 1.
3204 **
3205 ** ^If the progress callback returns non-zero, the operation is
3206 ** interrupted.  This feature can be used to implement a
3207 ** "Cancel" button on a GUI progress dialog box.
3208 **
3209 ** The progress handler callback must not do anything that will modify
3210 ** the database connection that invoked the progress handler.
3211 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
3212 ** database connections for the meaning of "modify" in this paragraph.
3213 **
3214 */
3215 SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
3216 
3217 /*
3218 ** CAPI3REF: Opening A New Database Connection
3219 ** CONSTRUCTOR: sqlite3
3220 **
3221 ** ^These routines open an SQLite database file as specified by the
3222 ** filename argument. ^The filename argument is interpreted as UTF-8 for
3223 ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
3224 ** order for sqlite3_open16(). ^(A [database connection] handle is usually
3225 ** returned in *ppDb, even if an error occurs.  The only exception is that
3226 ** if SQLite is unable to allocate memory to hold the [sqlite3] object,
3227 ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
3228 ** object.)^ ^(If the database is opened (and/or created) successfully, then
3229 ** [SQLITE_OK] is returned.  Otherwise an [error code] is returned.)^ ^The
3230 ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
3231 ** an English language description of the error following a failure of any
3232 ** of the sqlite3_open() routines.
3233 **
3234 ** ^The default encoding will be UTF-8 for databases created using
3235 ** sqlite3_open() or sqlite3_open_v2().  ^The default encoding for databases
3236 ** created using sqlite3_open16() will be UTF-16 in the native byte order.
3237 **
3238 ** Whether or not an error occurs when it is opened, resources
3239 ** associated with the [database connection] handle should be released by
3240 ** passing it to [sqlite3_close()] when it is no longer required.
3241 **
3242 ** The sqlite3_open_v2() interface works like sqlite3_open()
3243 ** except that it accepts two additional parameters for additional control
3244 ** over the new database connection.  ^(The flags parameter to
3245 ** sqlite3_open_v2() can take one of
3246 ** the following three values, optionally combined with the
3247 ** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE],
3248 ** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^
3249 **
3250 ** <dl>
3251 ** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
3252 ** <dd>The database is opened in read-only mode.  If the database does not
3253 ** already exist, an error is returned.</dd>)^
3254 **
3255 ** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
3256 ** <dd>The database is opened for reading and writing if possible, or reading
3257 ** only if the file is write protected by the operating system.  In either
3258 ** case the database must already exist, otherwise an error is returned.</dd>)^
3259 **
3260 ** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
3261 ** <dd>The database is opened for reading and writing, and is created if
3262 ** it does not already exist. This is the behavior that is always used for
3263 ** sqlite3_open() and sqlite3_open16().</dd>)^
3264 ** </dl>
3265 **
3266 ** If the 3rd parameter to sqlite3_open_v2() is not one of the
3267 ** combinations shown above optionally combined with other
3268 ** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits]
3269 ** then the behavior is undefined.
3270 **
3271 ** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection
3272 ** opens in the multi-thread [threading mode] as long as the single-thread
3273 ** mode has not been set at compile-time or start-time.  ^If the
3274 ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens
3275 ** in the serialized [threading mode] unless single-thread was
3276 ** previously selected at compile-time or start-time.
3277 ** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be
3278 ** eligible to use [shared cache mode], regardless of whether or not shared
3279 ** cache is enabled using [sqlite3_enable_shared_cache()].  ^The
3280 ** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not
3281 ** participate in [shared cache mode] even if it is enabled.
3282 **
3283 ** ^The fourth parameter to sqlite3_open_v2() is the name of the
3284 ** [sqlite3_vfs] object that defines the operating system interface that
3285 ** the new database connection should use.  ^If the fourth parameter is
3286 ** a NULL pointer then the default [sqlite3_vfs] object is used.
3287 **
3288 ** ^If the filename is ":memory:", then a private, temporary in-memory database
3289 ** is created for the connection.  ^This in-memory database will vanish when
3290 ** the database connection is closed.  Future versions of SQLite might
3291 ** make use of additional special filenames that begin with the ":" character.
3292 ** It is recommended that when a database filename actually does begin with
3293 ** a ":" character you should prefix the filename with a pathname such as
3294 ** "./" to avoid ambiguity.
3295 **
3296 ** ^If the filename is an empty string, then a private, temporary
3297 ** on-disk database will be created.  ^This private database will be
3298 ** automatically deleted as soon as the database connection is closed.
3299 **
3300 ** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
3301 **
3302 ** ^If [URI filename] interpretation is enabled, and the filename argument
3303 ** begins with "file:", then the filename is interpreted as a URI. ^URI
3304 ** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
3305 ** set in the third argument to sqlite3_open_v2(), or if it has
3306 ** been enabled globally using the [SQLITE_CONFIG_URI] option with the
3307 ** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
3308 ** URI filename interpretation is turned off
3309 ** by default, but future releases of SQLite might enable URI filename
3310 ** interpretation by default.  See "[URI filenames]" for additional
3311 ** information.
3312 **
3313 ** URI filenames are parsed according to RFC 3986. ^If the URI contains an
3314 ** authority, then it must be either an empty string or the string
3315 ** "localhost". ^If the authority is not an empty string or "localhost", an
3316 ** error is returned to the caller. ^The fragment component of a URI, if
3317 ** present, is ignored.
3318 **
3319 ** ^SQLite uses the path component of the URI as the name of the disk file
3320 ** which contains the database. ^If the path begins with a '/' character,
3321 ** then it is interpreted as an absolute path. ^If the path does not begin
3322 ** with a '/' (meaning that the authority section is omitted from the URI)
3323 ** then the path is interpreted as a relative path.
3324 ** ^(On windows, the first component of an absolute path
3325 ** is a drive specification (e.g. "C:").)^
3326 **
3327 ** [[core URI query parameters]]
3328 ** The query component of a URI may contain parameters that are interpreted
3329 ** either by SQLite itself, or by a [VFS | custom VFS implementation].
3330 ** SQLite and its built-in [VFSes] interpret the
3331 ** following query parameters:
3332 **
3333 ** <ul>
3334 **   <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
3335 **     a VFS object that provides the operating system interface that should
3336 **     be used to access the database file on disk. ^If this option is set to
3337 **     an empty string the default VFS object is used. ^Specifying an unknown
3338 **     VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
3339 **     present, then the VFS specified by the option takes precedence over
3340 **     the value passed as the fourth parameter to sqlite3_open_v2().
3341 **
3342 **   <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw",
3343 **     "rwc", or "memory". Attempting to set it to any other value is
3344 **     an error)^.
3345 **     ^If "ro" is specified, then the database is opened for read-only
3346 **     access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the
3347 **     third argument to sqlite3_open_v2(). ^If the mode option is set to
3348 **     "rw", then the database is opened for read-write (but not create)
3349 **     access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had
3350 **     been set. ^Value "rwc" is equivalent to setting both
3351 **     SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE.  ^If the mode option is
3352 **     set to "memory" then a pure [in-memory database] that never reads
3353 **     or writes from disk is used. ^It is an error to specify a value for
3354 **     the mode parameter that is less restrictive than that specified by
3355 **     the flags passed in the third parameter to sqlite3_open_v2().
3356 **
3357 **   <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
3358 **     "private". ^Setting it to "shared" is equivalent to setting the
3359 **     SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
3360 **     sqlite3_open_v2(). ^Setting the cache parameter to "private" is
3361 **     equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
3362 **     ^If sqlite3_open_v2() is used and the "cache" parameter is present in
3363 **     a URI filename, its value overrides any behavior requested by setting
3364 **     SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.
3365 **
3366 **  <li> <b>psow</b>: ^The psow parameter indicates whether or not the
3367 **     [powersafe overwrite] property does or does not apply to the
3368 **     storage media on which the database file resides.
3369 **
3370 **  <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter
3371 **     which if set disables file locking in rollback journal modes.  This
3372 **     is useful for accessing a database on a filesystem that does not
3373 **     support locking.  Caution:  Database corruption might result if two
3374 **     or more processes write to the same database and any one of those
3375 **     processes uses nolock=1.
3376 **
3377 **  <li> <b>immutable</b>: ^The immutable parameter is a boolean query
3378 **     parameter that indicates that the database file is stored on
3379 **     read-only media.  ^When immutable is set, SQLite assumes that the
3380 **     database file cannot be changed, even by a process with higher
3381 **     privilege, and so the database is opened read-only and all locking
3382 **     and change detection is disabled.  Caution: Setting the immutable
3383 **     property on a database file that does in fact change can result
3384 **     in incorrect query results and/or [SQLITE_CORRUPT] errors.
3385 **     See also: [SQLITE_IOCAP_IMMUTABLE].
3386 **
3387 ** </ul>
3388 **
3389 ** ^Specifying an unknown parameter in the query component of a URI is not an
3390 ** error.  Future versions of SQLite might understand additional query
3391 ** parameters.  See "[query parameters with special meaning to SQLite]" for
3392 ** additional information.
3393 **
3394 ** [[URI filename examples]] <h3>URI filename examples</h3>
3395 **
3396 ** <table border="1" align=center cellpadding=5>
3397 ** <tr><th> URI filenames <th> Results
3398 ** <tr><td> file:data.db <td>
3399 **          Open the file "data.db" in the current directory.
3400 ** <tr><td> file:/home/fred/data.db<br>
3401 **          file:///home/fred/data.db <br>
3402 **          file://localhost/home/fred/data.db <br> <td>
3403 **          Open the database file "/home/fred/data.db".
3404 ** <tr><td> file://darkstar/home/fred/data.db <td>
3405 **          An error. "darkstar" is not a recognized authority.
3406 ** <tr><td style="white-space:nowrap">
3407 **          file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
3408 **     <td> Windows only: Open the file "data.db" on fred's desktop on drive
3409 **          C:. Note that the %20 escaping in this example is not strictly
3410 **          necessary - space characters can be used literally
3411 **          in URI filenames.
3412 ** <tr><td> file:data.db?mode=ro&cache=private <td>
3413 **          Open file "data.db" in the current directory for read-only access.
3414 **          Regardless of whether or not shared-cache mode is enabled by
3415 **          default, use a private cache.
3416 ** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td>
3417 **          Open file "/home/fred/data.db". Use the special VFS "unix-dotfile"
3418 **          that uses dot-files in place of posix advisory locking.
3419 ** <tr><td> file:data.db?mode=readonly <td>
3420 **          An error. "readonly" is not a valid option for the "mode" parameter.
3421 ** </table>
3422 **
3423 ** ^URI hexadecimal escape sequences (%HH) are supported within the path and
3424 ** query components of a URI. A hexadecimal escape sequence consists of a
3425 ** percent sign - "%" - followed by exactly two hexadecimal digits
3426 ** specifying an octet value. ^Before the path or query components of a
3427 ** URI filename are interpreted, they are encoded using UTF-8 and all
3428 ** hexadecimal escape sequences replaced by a single byte containing the
3429 ** corresponding octet. If this process generates an invalid UTF-8 encoding,
3430 ** the results are undefined.
3431 **
3432 ** <b>Note to Windows users:</b>  The encoding used for the filename argument
3433 ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
3434 ** codepage is currently defined.  Filenames containing international
3435 ** characters must be converted to UTF-8 prior to passing them into
3436 ** sqlite3_open() or sqlite3_open_v2().
3437 **
3438 ** <b>Note to Windows Runtime users:</b>  The temporary directory must be set
3439 ** prior to calling sqlite3_open() or sqlite3_open_v2().  Otherwise, various
3440 ** features that require the use of temporary files may fail.
3441 **
3442 ** See also: [sqlite3_temp_directory]
3443 */
3444 SQLITE_API int sqlite3_open(
3445   const char *filename,   /* Database filename (UTF-8) */
3446   sqlite3 **ppDb          /* OUT: SQLite db handle */
3447 );
3448 SQLITE_API int sqlite3_open16(
3449   const void *filename,   /* Database filename (UTF-16) */
3450   sqlite3 **ppDb          /* OUT: SQLite db handle */
3451 );
3452 SQLITE_API int sqlite3_open_v2(
3453   const char *filename,   /* Database filename (UTF-8) */
3454   sqlite3 **ppDb,         /* OUT: SQLite db handle */
3455   int flags,              /* Flags */
3456   const char *zVfs        /* Name of VFS module to use */
3457 );
3458 
3459 /*
3460 ** CAPI3REF: Obtain Values For URI Parameters
3461 **
3462 ** These are utility routines, useful to VFS implementations, that check
3463 ** to see if a database file was a URI that contained a specific query
3464 ** parameter, and if so obtains the value of that query parameter.
3465 **
3466 ** If F is the database filename pointer passed into the xOpen() method of
3467 ** a VFS implementation when the flags parameter to xOpen() has one or
3468 ** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and
3469 ** P is the name of the query parameter, then
3470 ** sqlite3_uri_parameter(F,P) returns the value of the P
3471 ** parameter if it exists or a NULL pointer if P does not appear as a
3472 ** query parameter on F.  If P is a query parameter of F
3473 ** has no explicit value, then sqlite3_uri_parameter(F,P) returns
3474 ** a pointer to an empty string.
3475 **
3476 ** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
3477 ** parameter and returns true (1) or false (0) according to the value
3478 ** of P.  The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
3479 ** value of query parameter P is one of "yes", "true", or "on" in any
3480 ** case or if the value begins with a non-zero number.  The
3481 ** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
3482 ** query parameter P is one of "no", "false", or "off" in any case or
3483 ** if the value begins with a numeric zero.  If P is not a query
3484 ** parameter on F or if the value of P is does not match any of the
3485 ** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).
3486 **
3487 ** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
3488 ** 64-bit signed integer and returns that integer, or D if P does not
3489 ** exist.  If the value of P is something other than an integer, then
3490 ** zero is returned.
3491 **
3492 ** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
3493 ** sqlite3_uri_boolean(F,P,B) returns B.  If F is not a NULL pointer and
3494 ** is not a database file pathname pointer that SQLite passed into the xOpen
3495 ** VFS method, then the behavior of this routine is undefined and probably
3496 ** undesirable.
3497 **
3498 ** See the [URI filename] documentation for additional information.
3499 */
3500 SQLITE_API const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam);
3501 SQLITE_API int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault);
3502 SQLITE_API sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64);
3503 
3504 
3505 /*
3506 ** CAPI3REF: Error Codes And Messages
3507 ** METHOD: sqlite3
3508 **
3509 ** ^If the most recent sqlite3_* API call associated with
3510 ** [database connection] D failed, then the sqlite3_errcode(D) interface
3511 ** returns the numeric [result code] or [extended result code] for that
3512 ** API call.
3513 ** ^The sqlite3_extended_errcode()
3514 ** interface is the same except that it always returns the
3515 ** [extended result code] even when extended result codes are
3516 ** disabled.
3517 **
3518 ** The values returned by sqlite3_errcode() and/or
3519 ** sqlite3_extended_errcode() might change with each API call.
3520 ** Except, there are some interfaces that are guaranteed to never
3521 ** change the value of the error code.  The error-code preserving
3522 ** interfaces are:
3523 **
3524 ** <ul>
3525 ** <li> sqlite3_errcode()
3526 ** <li> sqlite3_extended_errcode()
3527 ** <li> sqlite3_errmsg()
3528 ** <li> sqlite3_errmsg16()
3529 ** </ul>
3530 **
3531 ** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
3532 ** text that describes the error, as either UTF-8 or UTF-16 respectively.
3533 ** ^(Memory to hold the error message string is managed internally.
3534 ** The application does not need to worry about freeing the result.
3535 ** However, the error string might be overwritten or deallocated by
3536 ** subsequent calls to other SQLite interface functions.)^
3537 **
3538 ** ^The sqlite3_errstr() interface returns the English-language text
3539 ** that describes the [result code], as UTF-8.
3540 ** ^(Memory to hold the error message string is managed internally
3541 ** and must not be freed by the application)^.
3542 **
3543 ** When the serialized [threading mode] is in use, it might be the
3544 ** case that a second error occurs on a separate thread in between
3545 ** the time of the first error and the call to these interfaces.
3546 ** When that happens, the second error will be reported since these
3547 ** interfaces always report the most recent result.  To avoid
3548 ** this, each thread can obtain exclusive use of the [database connection] D
3549 ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
3550 ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
3551 ** all calls to the interfaces listed here are completed.
3552 **
3553 ** If an interface fails with SQLITE_MISUSE, that means the interface
3554 ** was invoked incorrectly by the application.  In that case, the
3555 ** error code and message may or may not be set.
3556 */
3557 SQLITE_API int sqlite3_errcode(sqlite3 *db);
3558 SQLITE_API int sqlite3_extended_errcode(sqlite3 *db);
3559 SQLITE_API const char *sqlite3_errmsg(sqlite3*);
3560 SQLITE_API const void *sqlite3_errmsg16(sqlite3*);
3561 SQLITE_API const char *sqlite3_errstr(int);
3562 
3563 /*
3564 ** CAPI3REF: Prepared Statement Object
3565 ** KEYWORDS: {prepared statement} {prepared statements}
3566 **
3567 ** An instance of this object represents a single SQL statement that
3568 ** has been compiled into binary form and is ready to be evaluated.
3569 **
3570 ** Think of each SQL statement as a separate computer program.  The
3571 ** original SQL text is source code.  A prepared statement object
3572 ** is the compiled object code.  All SQL must be converted into a
3573 ** prepared statement before it can be run.
3574 **
3575 ** The life-cycle of a prepared statement object usually goes like this:
3576 **
3577 ** <ol>
3578 ** <li> Create the prepared statement object using [sqlite3_prepare_v2()].
3579 ** <li> Bind values to [parameters] using the sqlite3_bind_*()
3580 **      interfaces.
3581 ** <li> Run the SQL by calling [sqlite3_step()] one or more times.
3582 ** <li> Reset the prepared statement using [sqlite3_reset()] then go back
3583 **      to step 2.  Do this zero or more times.
3584 ** <li> Destroy the object using [sqlite3_finalize()].
3585 ** </ol>
3586 */
3587 typedef struct sqlite3_stmt sqlite3_stmt;
3588 
3589 /*
3590 ** CAPI3REF: Run-time Limits
3591 ** METHOD: sqlite3
3592 **
3593 ** ^(This interface allows the size of various constructs to be limited
3594 ** on a connection by connection basis.  The first parameter is the
3595 ** [database connection] whose limit is to be set or queried.  The
3596 ** second parameter is one of the [limit categories] that define a
3597 ** class of constructs to be size limited.  The third parameter is the
3598 ** new limit for that construct.)^
3599 **
3600 ** ^If the new limit is a negative number, the limit is unchanged.
3601 ** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
3602 ** [limits | hard upper bound]
3603 ** set at compile-time by a C preprocessor macro called
3604 ** [limits | SQLITE_MAX_<i>NAME</i>].
3605 ** (The "_LIMIT_" in the name is changed to "_MAX_".))^
3606 ** ^Attempts to increase a limit above its hard upper bound are
3607 ** silently truncated to the hard upper bound.
3608 **
3609 ** ^Regardless of whether or not the limit was changed, the
3610 ** [sqlite3_limit()] interface returns the prior value of the limit.
3611 ** ^Hence, to find the current value of a limit without changing it,
3612 ** simply invoke this interface with the third parameter set to -1.
3613 **
3614 ** Run-time limits are intended for use in applications that manage
3615 ** both their own internal database and also databases that are controlled
3616 ** by untrusted external sources.  An example application might be a
3617 ** web browser that has its own databases for storing history and
3618 ** separate databases controlled by JavaScript applications downloaded
3619 ** off the Internet.  The internal databases can be given the
3620 ** large, default limits.  Databases managed by external sources can
3621 ** be given much smaller limits designed to prevent a denial of service
3622 ** attack.  Developers might also want to use the [sqlite3_set_authorizer()]
3623 ** interface to further control untrusted SQL.  The size of the database
3624 ** created by an untrusted script can be contained using the
3625 ** [max_page_count] [PRAGMA].
3626 **
3627 ** New run-time limit categories may be added in future releases.
3628 */
3629 SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal);
3630 
3631 /*
3632 ** CAPI3REF: Run-Time Limit Categories
3633 ** KEYWORDS: {limit category} {*limit categories}
3634 **
3635 ** These constants define various performance limits
3636 ** that can be lowered at run-time using [sqlite3_limit()].
3637 ** The synopsis of the meanings of the various limits is shown below.
3638 ** Additional information is available at [limits | Limits in SQLite].
3639 **
3640 ** <dl>
3641 ** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt>
3642 ** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
3643 **
3644 ** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
3645 ** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
3646 **
3647 ** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt>
3648 ** <dd>The maximum number of columns in a table definition or in the
3649 ** result set of a [SELECT] or the maximum number of columns in an index
3650 ** or in an ORDER BY or GROUP BY clause.</dd>)^
3651 **
3652 ** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
3653 ** <dd>The maximum depth of the parse tree on any expression.</dd>)^
3654 **
3655 ** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
3656 ** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
3657 **
3658 ** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
3659 ** <dd>The maximum number of instructions in a virtual machine program
3660 ** used to implement an SQL statement.  If [sqlite3_prepare_v2()] or
3661 ** the equivalent tries to allocate space for more than this many opcodes
3662 ** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^
3663 **
3664 ** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
3665 ** <dd>The maximum number of arguments on a function.</dd>)^
3666 **
3667 ** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
3668 ** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
3669 **
3670 ** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]]
3671 ** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
3672 ** <dd>The maximum length of the pattern argument to the [LIKE] or
3673 ** [GLOB] operators.</dd>)^
3674 **
3675 ** [[SQLITE_LIMIT_VARIABLE_NUMBER]]
3676 ** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
3677 ** <dd>The maximum index number of any [parameter] in an SQL statement.)^
3678 **
3679 ** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
3680 ** <dd>The maximum depth of recursion for triggers.</dd>)^
3681 **
3682 ** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt>
3683 ** <dd>The maximum number of auxiliary worker threads that a single
3684 ** [prepared statement] may start.</dd>)^
3685 ** </dl>
3686 */
3687 #define SQLITE_LIMIT_LENGTH                    0
3688 #define SQLITE_LIMIT_SQL_LENGTH                1
3689 #define SQLITE_LIMIT_COLUMN                    2
3690 #define SQLITE_LIMIT_EXPR_DEPTH                3
3691 #define SQLITE_LIMIT_COMPOUND_SELECT           4
3692 #define SQLITE_LIMIT_VDBE_OP                   5
3693 #define SQLITE_LIMIT_FUNCTION_ARG              6
3694 #define SQLITE_LIMIT_ATTACHED                  7
3695 #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH       8
3696 #define SQLITE_LIMIT_VARIABLE_NUMBER           9
3697 #define SQLITE_LIMIT_TRIGGER_DEPTH            10
3698 #define SQLITE_LIMIT_WORKER_THREADS           11
3699 
3700 /*
3701 ** CAPI3REF: Prepare Flags
3702 **
3703 ** These constants define various flags that can be passed into
3704 ** "prepFlags" parameter of the [sqlite3_prepare_v3()] and
3705 ** [sqlite3_prepare16_v3()] interfaces.
3706 **
3707 ** New flags may be added in future releases of SQLite.
3708 **
3709 ** <dl>
3710 ** [[SQLITE_PREPARE_PERSISTENT]] ^(<dt>SQLITE_PREPARE_PERSISTENT</dt>
3711 ** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner
3712 ** that the prepared statement will be retained for a long time and
3713 ** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()]
3714 ** and [sqlite3_prepare16_v3()] assume that the prepared statement will
3715 ** be used just once or at most a few times and then destroyed using
3716 ** [sqlite3_finalize()] relatively soon. The current implementation acts
3717 ** on this hint by avoiding the use of [lookaside memory] so as not to
3718 ** deplete the limited store of lookaside memory. Future versions of
3719 ** SQLite may act on this hint differently.
3720 **
3721 ** [[SQLITE_PREPARE_NORMALIZE]] <dt>SQLITE_PREPARE_NORMALIZE</dt>
3722 ** <dd>The SQLITE_PREPARE_NORMALIZE flag is a no-op. This flag used
3723 ** to be required for any prepared statement that wanted to use the
3724 ** [sqlite3_normalized_sql()] interface.  However, the
3725 ** [sqlite3_normalized_sql()] interface is now available to all
3726 ** prepared statements, regardless of whether or not they use this
3727 ** flag.
3728 **
3729 ** [[SQLITE_PREPARE_NO_VTAB]] <dt>SQLITE_PREPARE_NO_VTAB</dt>
3730 ** <dd>The SQLITE_PREPARE_NO_VTAB flag causes the SQL compiler
3731 ** to return an error (error code SQLITE_ERROR) if the statement uses
3732 ** any virtual tables.
3733 ** </dl>
3734 */
3735 #define SQLITE_PREPARE_PERSISTENT              0x01
3736 #define SQLITE_PREPARE_NORMALIZE               0x02
3737 #define SQLITE_PREPARE_NO_VTAB                 0x04
3738 
3739 /*
3740 ** CAPI3REF: Compiling An SQL Statement
3741 ** KEYWORDS: {SQL statement compiler}
3742 ** METHOD: sqlite3
3743 ** CONSTRUCTOR: sqlite3_stmt
3744 **
3745 ** To execute an SQL statement, it must first be compiled into a byte-code
3746 ** program using one of these routines.  Or, in other words, these routines
3747 ** are constructors for the [prepared statement] object.
3748 **
3749 ** The preferred routine to use is [sqlite3_prepare_v2()].  The
3750 ** [sqlite3_prepare()] interface is legacy and should be avoided.
3751 ** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used
3752 ** for special purposes.
3753 **
3754 ** The use of the UTF-8 interfaces is preferred, as SQLite currently
3755 ** does all parsing using UTF-8.  The UTF-16 interfaces are provided
3756 ** as a convenience.  The UTF-16 interfaces work by converting the
3757 ** input text into UTF-8, then invoking the corresponding UTF-8 interface.
3758 **
3759 ** The first argument, "db", is a [database connection] obtained from a
3760 ** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
3761 ** [sqlite3_open16()].  The database connection must not have been closed.
3762 **
3763 ** The second argument, "zSql", is the statement to be compiled, encoded
3764 ** as either UTF-8 or UTF-16.  The sqlite3_prepare(), sqlite3_prepare_v2(),
3765 ** and sqlite3_prepare_v3()
3766 ** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(),
3767 ** and sqlite3_prepare16_v3() use UTF-16.
3768 **
3769 ** ^If the nByte argument is negative, then zSql is read up to the
3770 ** first zero terminator. ^If nByte is positive, then it is the
3771 ** number of bytes read from zSql.  ^If nByte is zero, then no prepared
3772 ** statement is generated.
3773 ** If the caller knows that the supplied string is nul-terminated, then
3774 ** there is a small performance advantage to passing an nByte parameter that
3775 ** is the number of bytes in the input string <i>including</i>
3776 ** the nul-terminator.
3777 **
3778 ** ^If pzTail is not NULL then *pzTail is made to point to the first byte
3779 ** past the end of the first SQL statement in zSql.  These routines only
3780 ** compile the first statement in zSql, so *pzTail is left pointing to
3781 ** what remains uncompiled.
3782 **
3783 ** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
3784 ** executed using [sqlite3_step()].  ^If there is an error, *ppStmt is set
3785 ** to NULL.  ^If the input text contains no SQL (if the input is an empty
3786 ** string or a comment) then *ppStmt is set to NULL.
3787 ** The calling procedure is responsible for deleting the compiled
3788 ** SQL statement using [sqlite3_finalize()] after it has finished with it.
3789 ** ppStmt may not be NULL.
3790 **
3791 ** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
3792 ** otherwise an [error code] is returned.
3793 **
3794 ** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(),
3795 ** and sqlite3_prepare16_v3() interfaces are recommended for all new programs.
3796 ** The older interfaces (sqlite3_prepare() and sqlite3_prepare16())
3797 ** are retained for backwards compatibility, but their use is discouraged.
3798 ** ^In the "vX" interfaces, the prepared statement
3799 ** that is returned (the [sqlite3_stmt] object) contains a copy of the
3800 ** original SQL text. This causes the [sqlite3_step()] interface to
3801 ** behave differently in three ways:
3802 **
3803 ** <ol>
3804 ** <li>
3805 ** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
3806 ** always used to do, [sqlite3_step()] will automatically recompile the SQL
3807 ** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY]
3808 ** retries will occur before sqlite3_step() gives up and returns an error.
3809 ** </li>
3810 **
3811 ** <li>
3812 ** ^When an error occurs, [sqlite3_step()] will return one of the detailed
3813 ** [error codes] or [extended error codes].  ^The legacy behavior was that
3814 ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
3815 ** and the application would have to make a second call to [sqlite3_reset()]
3816 ** in order to find the underlying cause of the problem. With the "v2" prepare
3817 ** interfaces, the underlying reason for the error is returned immediately.
3818 ** </li>
3819 **
3820 ** <li>
3821 ** ^If the specific value bound to [parameter | host parameter] in the
3822 ** WHERE clause might influence the choice of query plan for a statement,
3823 ** then the statement will be automatically recompiled, as if there had been
3824 ** a schema change, on the first  [sqlite3_step()] call following any change
3825 ** to the [sqlite3_bind_text | bindings] of that [parameter].
3826 ** ^The specific value of WHERE-clause [parameter] might influence the
3827 ** choice of query plan if the parameter is the left-hand side of a [LIKE]
3828 ** or [GLOB] operator or if the parameter is compared to an indexed column
3829 ** and the [SQLITE_ENABLE_STAT4] compile-time option is enabled.
3830 ** </li>
3831 ** </ol>
3832 **
3833 ** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having
3834 ** the extra prepFlags parameter, which is a bit array consisting of zero or
3835 ** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags.  ^The
3836 ** sqlite3_prepare_v2() interface works exactly the same as
3837 ** sqlite3_prepare_v3() with a zero prepFlags parameter.
3838 */
3839 SQLITE_API int sqlite3_prepare(
3840   sqlite3 *db,            /* Database handle */
3841   const char *zSql,       /* SQL statement, UTF-8 encoded */
3842   int nByte,              /* Maximum length of zSql in bytes. */
3843   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
3844   const char **pzTail     /* OUT: Pointer to unused portion of zSql */
3845 );
3846 SQLITE_API int sqlite3_prepare_v2(
3847   sqlite3 *db,            /* Database handle */
3848   const char *zSql,       /* SQL statement, UTF-8 encoded */
3849   int nByte,              /* Maximum length of zSql in bytes. */
3850   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
3851   const char **pzTail     /* OUT: Pointer to unused portion of zSql */
3852 );
3853 SQLITE_API int sqlite3_prepare_v3(
3854   sqlite3 *db,            /* Database handle */
3855   const char *zSql,       /* SQL statement, UTF-8 encoded */
3856   int nByte,              /* Maximum length of zSql in bytes. */
3857   unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
3858   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
3859   const char **pzTail     /* OUT: Pointer to unused portion of zSql */
3860 );
3861 SQLITE_API int sqlite3_prepare16(
3862   sqlite3 *db,            /* Database handle */
3863   const void *zSql,       /* SQL statement, UTF-16 encoded */
3864   int nByte,              /* Maximum length of zSql in bytes. */
3865   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
3866   const void **pzTail     /* OUT: Pointer to unused portion of zSql */
3867 );
3868 SQLITE_API int sqlite3_prepare16_v2(
3869   sqlite3 *db,            /* Database handle */
3870   const void *zSql,       /* SQL statement, UTF-16 encoded */
3871   int nByte,              /* Maximum length of zSql in bytes. */
3872   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
3873   const void **pzTail     /* OUT: Pointer to unused portion of zSql */
3874 );
3875 SQLITE_API int sqlite3_prepare16_v3(
3876   sqlite3 *db,            /* Database handle */
3877   const void *zSql,       /* SQL statement, UTF-16 encoded */
3878   int nByte,              /* Maximum length of zSql in bytes. */
3879   unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
3880   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
3881   const void **pzTail     /* OUT: Pointer to unused portion of zSql */
3882 );
3883 
3884 /*
3885 ** CAPI3REF: Retrieving Statement SQL
3886 ** METHOD: sqlite3_stmt
3887 **
3888 ** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8
3889 ** SQL text used to create [prepared statement] P if P was
3890 ** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()],
3891 ** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()].
3892 ** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8
3893 ** string containing the SQL text of prepared statement P with
3894 ** [bound parameters] expanded.
3895 ** ^The sqlite3_normalized_sql(P) interface returns a pointer to a UTF-8
3896 ** string containing the normalized SQL text of prepared statement P.  The
3897 ** semantics used to normalize a SQL statement are unspecified and subject
3898 ** to change.  At a minimum, literal values will be replaced with suitable
3899 ** placeholders.
3900 **
3901 ** ^(For example, if a prepared statement is created using the SQL
3902 ** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345
3903 ** and parameter :xyz is unbound, then sqlite3_sql() will return
3904 ** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql()
3905 ** will return "SELECT 2345,NULL".)^
3906 **
3907 ** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory
3908 ** is available to hold the result, or if the result would exceed the
3909 ** the maximum string length determined by the [SQLITE_LIMIT_LENGTH].
3910 **
3911 ** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of
3912 ** bound parameter expansions.  ^The [SQLITE_OMIT_TRACE] compile-time
3913 ** option causes sqlite3_expanded_sql() to always return NULL.
3914 **
3915 ** ^The strings returned by sqlite3_sql(P) and sqlite3_normalized_sql(P)
3916 ** are managed by SQLite and are automatically freed when the prepared
3917 ** statement is finalized.
3918 ** ^The string returned by sqlite3_expanded_sql(P), on the other hand,
3919 ** is obtained from [sqlite3_malloc()] and must be free by the application
3920 ** by passing it to [sqlite3_free()].
3921 */
3922 SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt);
3923 SQLITE_API char *sqlite3_expanded_sql(sqlite3_stmt *pStmt);
3924 SQLITE_API const char *sqlite3_normalized_sql(sqlite3_stmt *pStmt);
3925 
3926 /*
3927 ** CAPI3REF: Determine If An SQL Statement Writes The Database
3928 ** METHOD: sqlite3_stmt
3929 **
3930 ** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
3931 ** and only if the [prepared statement] X makes no direct changes to
3932 ** the content of the database file.
3933 **
3934 ** Note that [application-defined SQL functions] or
3935 ** [virtual tables] might change the database indirectly as a side effect.
3936 ** ^(For example, if an application defines a function "eval()" that
3937 ** calls [sqlite3_exec()], then the following SQL statement would
3938 ** change the database file through side-effects:
3939 **
3940 ** <blockquote><pre>
3941 **    SELECT eval('DELETE FROM t1') FROM t2;
3942 ** </pre></blockquote>
3943 **
3944 ** But because the [SELECT] statement does not change the database file
3945 ** directly, sqlite3_stmt_readonly() would still return true.)^
3946 **
3947 ** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
3948 ** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
3949 ** since the statements themselves do not actually modify the database but
3950 ** rather they control the timing of when other statements modify the
3951 ** database.  ^The [ATTACH] and [DETACH] statements also cause
3952 ** sqlite3_stmt_readonly() to return true since, while those statements
3953 ** change the configuration of a database connection, they do not make
3954 ** changes to the content of the database files on disk.
3955 ** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since
3956 ** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and
3957 ** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so
3958 ** sqlite3_stmt_readonly() returns false for those commands.
3959 */
3960 SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
3961 
3962 /*
3963 ** CAPI3REF: Query The EXPLAIN Setting For A Prepared Statement
3964 ** METHOD: sqlite3_stmt
3965 **
3966 ** ^The sqlite3_stmt_isexplain(S) interface returns 1 if the
3967 ** prepared statement S is an EXPLAIN statement, or 2 if the
3968 ** statement S is an EXPLAIN QUERY PLAN.
3969 ** ^The sqlite3_stmt_isexplain(S) interface returns 0 if S is
3970 ** an ordinary statement or a NULL pointer.
3971 */
3972 SQLITE_API int sqlite3_stmt_isexplain(sqlite3_stmt *pStmt);
3973 
3974 /*
3975 ** CAPI3REF: Determine If A Prepared Statement Has Been Reset
3976 ** METHOD: sqlite3_stmt
3977 **
3978 ** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
3979 ** [prepared statement] S has been stepped at least once using
3980 ** [sqlite3_step(S)] but has neither run to completion (returned
3981 ** [SQLITE_DONE] from [sqlite3_step(S)]) nor
3982 ** been reset using [sqlite3_reset(S)].  ^The sqlite3_stmt_busy(S)
3983 ** interface returns false if S is a NULL pointer.  If S is not a
3984 ** NULL pointer and is not a pointer to a valid [prepared statement]
3985 ** object, then the behavior is undefined and probably undesirable.
3986 **
3987 ** This interface can be used in combination [sqlite3_next_stmt()]
3988 ** to locate all prepared statements associated with a database
3989 ** connection that are in need of being reset.  This can be used,
3990 ** for example, in diagnostic routines to search for prepared
3991 ** statements that are holding a transaction open.
3992 */
3993 SQLITE_API int sqlite3_stmt_busy(sqlite3_stmt*);
3994 
3995 /*
3996 ** CAPI3REF: Dynamically Typed Value Object
3997 ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
3998 **
3999 ** SQLite uses the sqlite3_value object to represent all values
4000 ** that can be stored in a database table. SQLite uses dynamic typing
4001 ** for the values it stores.  ^Values stored in sqlite3_value objects
4002 ** can be integers, floating point values, strings, BLOBs, or NULL.
4003 **
4004 ** An sqlite3_value object may be either "protected" or "unprotected".
4005 ** Some interfaces require a protected sqlite3_value.  Other interfaces
4006 ** will accept either a protected or an unprotected sqlite3_value.
4007 ** Every interface that accepts sqlite3_value arguments specifies
4008 ** whether or not it requires a protected sqlite3_value.  The
4009 ** [sqlite3_value_dup()] interface can be used to construct a new
4010 ** protected sqlite3_value from an unprotected sqlite3_value.
4011 **
4012 ** The terms "protected" and "unprotected" refer to whether or not
4013 ** a mutex is held.  An internal mutex is held for a protected
4014 ** sqlite3_value object but no mutex is held for an unprotected
4015 ** sqlite3_value object.  If SQLite is compiled to be single-threaded
4016 ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
4017 ** or if SQLite is run in one of reduced mutex modes
4018 ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
4019 ** then there is no distinction between protected and unprotected
4020 ** sqlite3_value objects and they can be used interchangeably.  However,
4021 ** for maximum code portability it is recommended that applications
4022 ** still make the distinction between protected and unprotected
4023 ** sqlite3_value objects even when not strictly required.
4024 **
4025 ** ^The sqlite3_value objects that are passed as parameters into the
4026 ** implementation of [application-defined SQL functions] are protected.
4027 ** ^The sqlite3_value object returned by
4028 ** [sqlite3_column_value()] is unprotected.
4029 ** Unprotected sqlite3_value objects may only be used as arguments
4030 ** to [sqlite3_result_value()], [sqlite3_bind_value()], and
4031 ** [sqlite3_value_dup()].
4032 ** The [sqlite3_value_blob | sqlite3_value_type()] family of
4033 ** interfaces require protected sqlite3_value objects.
4034 */
4035 typedef struct sqlite3_value sqlite3_value;
4036 
4037 /*
4038 ** CAPI3REF: SQL Function Context Object
4039 **
4040 ** The context in which an SQL function executes is stored in an
4041 ** sqlite3_context object.  ^A pointer to an sqlite3_context object
4042 ** is always first parameter to [application-defined SQL functions].
4043 ** The application-defined SQL function implementation will pass this
4044 ** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
4045 ** [sqlite3_aggregate_context()], [sqlite3_user_data()],
4046 ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
4047 ** and/or [sqlite3_set_auxdata()].
4048 */
4049 typedef struct sqlite3_context sqlite3_context;
4050 
4051 /*
4052 ** CAPI3REF: Binding Values To Prepared Statements
4053 ** KEYWORDS: {host parameter} {host parameters} {host parameter name}
4054 ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
4055 ** METHOD: sqlite3_stmt
4056 **
4057 ** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
4058 ** literals may be replaced by a [parameter] that matches one of following
4059 ** templates:
4060 **
4061 ** <ul>
4062 ** <li>  ?
4063 ** <li>  ?NNN
4064 ** <li>  :VVV
4065 ** <li>  @VVV
4066 ** <li>  $VVV
4067 ** </ul>
4068 **
4069 ** In the templates above, NNN represents an integer literal,
4070 ** and VVV represents an alphanumeric identifier.)^  ^The values of these
4071 ** parameters (also called "host parameter names" or "SQL parameters")
4072 ** can be set using the sqlite3_bind_*() routines defined here.
4073 **
4074 ** ^The first argument to the sqlite3_bind_*() routines is always
4075 ** a pointer to the [sqlite3_stmt] object returned from
4076 ** [sqlite3_prepare_v2()] or its variants.
4077 **
4078 ** ^The second argument is the index of the SQL parameter to be set.
4079 ** ^The leftmost SQL parameter has an index of 1.  ^When the same named
4080 ** SQL parameter is used more than once, second and subsequent
4081 ** occurrences have the same index as the first occurrence.
4082 ** ^The index for named parameters can be looked up using the
4083 ** [sqlite3_bind_parameter_index()] API if desired.  ^The index
4084 ** for "?NNN" parameters is the value of NNN.
4085 ** ^The NNN value must be between 1 and the [sqlite3_limit()]
4086 ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999).
4087 **
4088 ** ^The third argument is the value to bind to the parameter.
4089 ** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16()
4090 ** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter
4091 ** is ignored and the end result is the same as sqlite3_bind_null().
4092 **
4093 ** ^(In those routines that have a fourth argument, its value is the
4094 ** number of bytes in the parameter.  To be clear: the value is the
4095 ** number of <u>bytes</u> in the value, not the number of characters.)^
4096 ** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()
4097 ** is negative, then the length of the string is
4098 ** the number of bytes up to the first zero terminator.
4099 ** If the fourth parameter to sqlite3_bind_blob() is negative, then
4100 ** the behavior is undefined.
4101 ** If a non-negative fourth parameter is provided to sqlite3_bind_text()
4102 ** or sqlite3_bind_text16() or sqlite3_bind_text64() then
4103 ** that parameter must be the byte offset
4104 ** where the NUL terminator would occur assuming the string were NUL
4105 ** terminated.  If any NUL characters occur at byte offsets less than
4106 ** the value of the fourth parameter then the resulting string value will
4107 ** contain embedded NULs.  The result of expressions involving strings
4108 ** with embedded NULs is undefined.
4109 **
4110 ** ^The fifth argument to the BLOB and string binding interfaces
4111 ** is a destructor used to dispose of the BLOB or
4112 ** string after SQLite has finished with it.  ^The destructor is called
4113 ** to dispose of the BLOB or string even if the call to the bind API fails,
4114 ** except the destructor is not called if the third parameter is a NULL
4115 ** pointer or the fourth parameter is negative.
4116 ** ^If the fifth argument is
4117 ** the special value [SQLITE_STATIC], then SQLite assumes that the
4118 ** information is in static, unmanaged space and does not need to be freed.
4119 ** ^If the fifth argument has the value [SQLITE_TRANSIENT], then
4120 ** SQLite makes its own private copy of the data immediately, before
4121 ** the sqlite3_bind_*() routine returns.
4122 **
4123 ** ^The sixth argument to sqlite3_bind_text64() must be one of
4124 ** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]
4125 ** to specify the encoding of the text in the third parameter.  If
4126 ** the sixth argument to sqlite3_bind_text64() is not one of the
4127 ** allowed values shown above, or if the text encoding is different
4128 ** from the encoding specified by the sixth parameter, then the behavior
4129 ** is undefined.
4130 **
4131 ** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
4132 ** is filled with zeroes.  ^A zeroblob uses a fixed amount of memory
4133 ** (just an integer to hold its size) while it is being processed.
4134 ** Zeroblobs are intended to serve as placeholders for BLOBs whose
4135 ** content is later written using
4136 ** [sqlite3_blob_open | incremental BLOB I/O] routines.
4137 ** ^A negative value for the zeroblob results in a zero-length BLOB.
4138 **
4139 ** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in
4140 ** [prepared statement] S to have an SQL value of NULL, but to also be
4141 ** associated with the pointer P of type T.  ^D is either a NULL pointer or
4142 ** a pointer to a destructor function for P. ^SQLite will invoke the
4143 ** destructor D with a single argument of P when it is finished using
4144 ** P.  The T parameter should be a static string, preferably a string
4145 ** literal. The sqlite3_bind_pointer() routine is part of the
4146 ** [pointer passing interface] added for SQLite 3.20.0.
4147 **
4148 ** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
4149 ** for the [prepared statement] or with a prepared statement for which
4150 ** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
4151 ** then the call will return [SQLITE_MISUSE].  If any sqlite3_bind_()
4152 ** routine is passed a [prepared statement] that has been finalized, the
4153 ** result is undefined and probably harmful.
4154 **
4155 ** ^Bindings are not cleared by the [sqlite3_reset()] routine.
4156 ** ^Unbound parameters are interpreted as NULL.
4157 **
4158 ** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
4159 ** [error code] if anything goes wrong.
4160 ** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB
4161 ** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or
4162 ** [SQLITE_MAX_LENGTH].
4163 ** ^[SQLITE_RANGE] is returned if the parameter
4164 ** index is out of range.  ^[SQLITE_NOMEM] is returned if malloc() fails.
4165 **
4166 ** See also: [sqlite3_bind_parameter_count()],
4167 ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
4168 */
4169 SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
4170 SQLITE_API int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64,
4171                         void(*)(void*));
4172 SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double);
4173 SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int);
4174 SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
4175 SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int);
4176 SQLITE_API int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*));
4177 SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
4178 SQLITE_API int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64,
4179                          void(*)(void*), unsigned char encoding);
4180 SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
4181 SQLITE_API int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*));
4182 SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
4183 SQLITE_API int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64);
4184 
4185 /*
4186 ** CAPI3REF: Number Of SQL Parameters
4187 ** METHOD: sqlite3_stmt
4188 **
4189 ** ^This routine can be used to find the number of [SQL parameters]
4190 ** in a [prepared statement].  SQL parameters are tokens of the
4191 ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
4192 ** placeholders for values that are [sqlite3_bind_blob | bound]
4193 ** to the parameters at a later time.
4194 **
4195 ** ^(This routine actually returns the index of the largest (rightmost)
4196 ** parameter. For all forms except ?NNN, this will correspond to the
4197 ** number of unique parameters.  If parameters of the ?NNN form are used,
4198 ** there may be gaps in the list.)^
4199 **
4200 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
4201 ** [sqlite3_bind_parameter_name()], and
4202 ** [sqlite3_bind_parameter_index()].
4203 */
4204 SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*);
4205 
4206 /*
4207 ** CAPI3REF: Name Of A Host Parameter
4208 ** METHOD: sqlite3_stmt
4209 **
4210 ** ^The sqlite3_bind_parameter_name(P,N) interface returns
4211 ** the name of the N-th [SQL parameter] in the [prepared statement] P.
4212 ** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
4213 ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
4214 ** respectively.
4215 ** In other words, the initial ":" or "$" or "@" or "?"
4216 ** is included as part of the name.)^
4217 ** ^Parameters of the form "?" without a following integer have no name
4218 ** and are referred to as "nameless" or "anonymous parameters".
4219 **
4220 ** ^The first host parameter has an index of 1, not 0.
4221 **
4222 ** ^If the value N is out of range or if the N-th parameter is
4223 ** nameless, then NULL is returned.  ^The returned string is
4224 ** always in UTF-8 encoding even if the named parameter was
4225 ** originally specified as UTF-16 in [sqlite3_prepare16()],
4226 ** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()].
4227 **
4228 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
4229 ** [sqlite3_bind_parameter_count()], and
4230 ** [sqlite3_bind_parameter_index()].
4231 */
4232 SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
4233 
4234 /*
4235 ** CAPI3REF: Index Of A Parameter With A Given Name
4236 ** METHOD: sqlite3_stmt
4237 **
4238 ** ^Return the index of an SQL parameter given its name.  ^The
4239 ** index value returned is suitable for use as the second
4240 ** parameter to [sqlite3_bind_blob|sqlite3_bind()].  ^A zero
4241 ** is returned if no matching parameter is found.  ^The parameter
4242 ** name must be given in UTF-8 even if the original statement
4243 ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or
4244 ** [sqlite3_prepare16_v3()].
4245 **
4246 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
4247 ** [sqlite3_bind_parameter_count()], and
4248 ** [sqlite3_bind_parameter_name()].
4249 */
4250 SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
4251 
4252 /*
4253 ** CAPI3REF: Reset All Bindings On A Prepared Statement
4254 ** METHOD: sqlite3_stmt
4255 **
4256 ** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
4257 ** the [sqlite3_bind_blob | bindings] on a [prepared statement].
4258 ** ^Use this routine to reset all host parameters to NULL.
4259 */
4260 SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*);
4261 
4262 /*
4263 ** CAPI3REF: Number Of Columns In A Result Set
4264 ** METHOD: sqlite3_stmt
4265 **
4266 ** ^Return the number of columns in the result set returned by the
4267 ** [prepared statement]. ^If this routine returns 0, that means the
4268 ** [prepared statement] returns no data (for example an [UPDATE]).
4269 ** ^However, just because this routine returns a positive number does not
4270 ** mean that one or more rows of data will be returned.  ^A SELECT statement
4271 ** will always have a positive sqlite3_column_count() but depending on the
4272 ** WHERE clause constraints and the table content, it might return no rows.
4273 **
4274 ** See also: [sqlite3_data_count()]
4275 */
4276 SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt);
4277 
4278 /*
4279 ** CAPI3REF: Column Names In A Result Set
4280 ** METHOD: sqlite3_stmt
4281 **
4282 ** ^These routines return the name assigned to a particular column
4283 ** in the result set of a [SELECT] statement.  ^The sqlite3_column_name()
4284 ** interface returns a pointer to a zero-terminated UTF-8 string
4285 ** and sqlite3_column_name16() returns a pointer to a zero-terminated
4286 ** UTF-16 string.  ^The first parameter is the [prepared statement]
4287 ** that implements the [SELECT] statement. ^The second parameter is the
4288 ** column number.  ^The leftmost column is number 0.
4289 **
4290 ** ^The returned string pointer is valid until either the [prepared statement]
4291 ** is destroyed by [sqlite3_finalize()] or until the statement is automatically
4292 ** reprepared by the first call to [sqlite3_step()] for a particular run
4293 ** or until the next call to
4294 ** sqlite3_column_name() or sqlite3_column_name16() on the same column.
4295 **
4296 ** ^If sqlite3_malloc() fails during the processing of either routine
4297 ** (for example during a conversion from UTF-8 to UTF-16) then a
4298 ** NULL pointer is returned.
4299 **
4300 ** ^The name of a result column is the value of the "AS" clause for
4301 ** that column, if there is an AS clause.  If there is no AS clause
4302 ** then the name of the column is unspecified and may change from
4303 ** one release of SQLite to the next.
4304 */
4305 SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N);
4306 SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N);
4307 
4308 /*
4309 ** CAPI3REF: Source Of Data In A Query Result
4310 ** METHOD: sqlite3_stmt
4311 **
4312 ** ^These routines provide a means to determine the database, table, and
4313 ** table column that is the origin of a particular result column in
4314 ** [SELECT] statement.
4315 ** ^The name of the database or table or column can be returned as
4316 ** either a UTF-8 or UTF-16 string.  ^The _database_ routines return
4317 ** the database name, the _table_ routines return the table name, and
4318 ** the origin_ routines return the column name.
4319 ** ^The returned string is valid until the [prepared statement] is destroyed
4320 ** using [sqlite3_finalize()] or until the statement is automatically
4321 ** reprepared by the first call to [sqlite3_step()] for a particular run
4322 ** or until the same information is requested
4323 ** again in a different encoding.
4324 **
4325 ** ^The names returned are the original un-aliased names of the
4326 ** database, table, and column.
4327 **
4328 ** ^The first argument to these interfaces is a [prepared statement].
4329 ** ^These functions return information about the Nth result column returned by
4330 ** the statement, where N is the second function argument.
4331 ** ^The left-most column is column 0 for these routines.
4332 **
4333 ** ^If the Nth column returned by the statement is an expression or
4334 ** subquery and is not a column value, then all of these functions return
4335 ** NULL.  ^These routine might also return NULL if a memory allocation error
4336 ** occurs.  ^Otherwise, they return the name of the attached database, table,
4337 ** or column that query result column was extracted from.
4338 **
4339 ** ^As with all other SQLite APIs, those whose names end with "16" return
4340 ** UTF-16 encoded strings and the other functions return UTF-8.
4341 **
4342 ** ^These APIs are only available if the library was compiled with the
4343 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
4344 **
4345 ** If two or more threads call one or more of these routines against the same
4346 ** prepared statement and column at the same time then the results are
4347 ** undefined.
4348 **
4349 ** If two or more threads call one or more
4350 ** [sqlite3_column_database_name | column metadata interfaces]
4351 ** for the same [prepared statement] and result column
4352 ** at the same time then the results are undefined.
4353 */
4354 SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int);
4355 SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
4356 SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int);
4357 SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
4358 SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
4359 SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
4360 
4361 /*
4362 ** CAPI3REF: Declared Datatype Of A Query Result
4363 ** METHOD: sqlite3_stmt
4364 **
4365 ** ^(The first parameter is a [prepared statement].
4366 ** If this statement is a [SELECT] statement and the Nth column of the
4367 ** returned result set of that [SELECT] is a table column (not an
4368 ** expression or subquery) then the declared type of the table
4369 ** column is returned.)^  ^If the Nth column of the result set is an
4370 ** expression or subquery, then a NULL pointer is returned.
4371 ** ^The returned string is always UTF-8 encoded.
4372 **
4373 ** ^(For example, given the database schema:
4374 **
4375 ** CREATE TABLE t1(c1 VARIANT);
4376 **
4377 ** and the following statement to be compiled:
4378 **
4379 ** SELECT c1 + 1, c1 FROM t1;
4380 **
4381 ** this routine would return the string "VARIANT" for the second result
4382 ** column (i==1), and a NULL pointer for the first result column (i==0).)^
4383 **
4384 ** ^SQLite uses dynamic run-time typing.  ^So just because a column
4385 ** is declared to contain a particular type does not mean that the
4386 ** data stored in that column is of the declared type.  SQLite is
4387 ** strongly typed, but the typing is dynamic not static.  ^Type
4388 ** is associated with individual values, not with the containers
4389 ** used to hold those values.
4390 */
4391 SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int);
4392 SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
4393 
4394 /*
4395 ** CAPI3REF: Evaluate An SQL Statement
4396 ** METHOD: sqlite3_stmt
4397 **
4398 ** After a [prepared statement] has been prepared using any of
4399 ** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()],
4400 ** or [sqlite3_prepare16_v3()] or one of the legacy
4401 ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
4402 ** must be called one or more times to evaluate the statement.
4403 **
4404 ** The details of the behavior of the sqlite3_step() interface depend
4405 ** on whether the statement was prepared using the newer "vX" interfaces
4406 ** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()],
4407 ** [sqlite3_prepare16_v2()] or the older legacy
4408 ** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()].  The use of the
4409 ** new "vX" interface is recommended for new applications but the legacy
4410 ** interface will continue to be supported.
4411 **
4412 ** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
4413 ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
4414 ** ^With the "v2" interface, any of the other [result codes] or
4415 ** [extended result codes] might be returned as well.
4416 **
4417 ** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
4418 ** database locks it needs to do its job.  ^If the statement is a [COMMIT]
4419 ** or occurs outside of an explicit transaction, then you can retry the
4420 ** statement.  If the statement is not a [COMMIT] and occurs within an
4421 ** explicit transaction then you should rollback the transaction before
4422 ** continuing.
4423 **
4424 ** ^[SQLITE_DONE] means that the statement has finished executing
4425 ** successfully.  sqlite3_step() should not be called again on this virtual
4426 ** machine without first calling [sqlite3_reset()] to reset the virtual
4427 ** machine back to its initial state.
4428 **
4429 ** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
4430 ** is returned each time a new row of data is ready for processing by the
4431 ** caller. The values may be accessed using the [column access functions].
4432 ** sqlite3_step() is called again to retrieve the next row of data.
4433 **
4434 ** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
4435 ** violation) has occurred.  sqlite3_step() should not be called again on
4436 ** the VM. More information may be found by calling [sqlite3_errmsg()].
4437 ** ^With the legacy interface, a more specific error code (for example,
4438 ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
4439 ** can be obtained by calling [sqlite3_reset()] on the
4440 ** [prepared statement].  ^In the "v2" interface,
4441 ** the more specific error code is returned directly by sqlite3_step().
4442 **
4443 ** [SQLITE_MISUSE] means that the this routine was called inappropriately.
4444 ** Perhaps it was called on a [prepared statement] that has
4445 ** already been [sqlite3_finalize | finalized] or on one that had
4446 ** previously returned [SQLITE_ERROR] or [SQLITE_DONE].  Or it could
4447 ** be the case that the same database connection is being used by two or
4448 ** more threads at the same moment in time.
4449 **
4450 ** For all versions of SQLite up to and including 3.6.23.1, a call to
4451 ** [sqlite3_reset()] was required after sqlite3_step() returned anything
4452 ** other than [SQLITE_ROW] before any subsequent invocation of
4453 ** sqlite3_step().  Failure to reset the prepared statement using
4454 ** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
4455 ** sqlite3_step().  But after [version 3.6.23.1] ([dateof:3.6.23.1],
4456 ** sqlite3_step() began
4457 ** calling [sqlite3_reset()] automatically in this circumstance rather
4458 ** than returning [SQLITE_MISUSE].  This is not considered a compatibility
4459 ** break because any application that ever receives an SQLITE_MISUSE error
4460 ** is broken by definition.  The [SQLITE_OMIT_AUTORESET] compile-time option
4461 ** can be used to restore the legacy behavior.
4462 **
4463 ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
4464 ** API always returns a generic error code, [SQLITE_ERROR], following any
4465 ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE].  You must call
4466 ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
4467 ** specific [error codes] that better describes the error.
4468 ** We admit that this is a goofy design.  The problem has been fixed
4469 ** with the "v2" interface.  If you prepare all of your SQL statements
4470 ** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()]
4471 ** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead
4472 ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
4473 ** then the more specific [error codes] are returned directly
4474 ** by sqlite3_step().  The use of the "vX" interfaces is recommended.
4475 */
4476 SQLITE_API int sqlite3_step(sqlite3_stmt*);
4477 
4478 /*
4479 ** CAPI3REF: Number of columns in a result set
4480 ** METHOD: sqlite3_stmt
4481 **
4482 ** ^The sqlite3_data_count(P) interface returns the number of columns in the
4483 ** current row of the result set of [prepared statement] P.
4484 ** ^If prepared statement P does not have results ready to return
4485 ** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of
4486 ** interfaces) then sqlite3_data_count(P) returns 0.
4487 ** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
4488 ** ^The sqlite3_data_count(P) routine returns 0 if the previous call to
4489 ** [sqlite3_step](P) returned [SQLITE_DONE].  ^The sqlite3_data_count(P)
4490 ** will return non-zero if previous call to [sqlite3_step](P) returned
4491 ** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum]
4492 ** where it always returns zero since each step of that multi-step
4493 ** pragma returns 0 columns of data.
4494 **
4495 ** See also: [sqlite3_column_count()]
4496 */
4497 SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
4498 
4499 /*
4500 ** CAPI3REF: Fundamental Datatypes
4501 ** KEYWORDS: SQLITE_TEXT
4502 **
4503 ** ^(Every value in SQLite has one of five fundamental datatypes:
4504 **
4505 ** <ul>
4506 ** <li> 64-bit signed integer
4507 ** <li> 64-bit IEEE floating point number
4508 ** <li> string
4509 ** <li> BLOB
4510 ** <li> NULL
4511 ** </ul>)^
4512 **
4513 ** These constants are codes for each of those types.
4514 **
4515 ** Note that the SQLITE_TEXT constant was also used in SQLite version 2
4516 ** for a completely different meaning.  Software that links against both
4517 ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
4518 ** SQLITE_TEXT.
4519 */
4520 #define SQLITE_INTEGER  1
4521 #define SQLITE_FLOAT    2
4522 #define SQLITE_BLOB     4
4523 #define SQLITE_NULL     5
4524 #ifdef SQLITE_TEXT
4525 # undef SQLITE_TEXT
4526 #else
4527 # define SQLITE_TEXT     3
4528 #endif
4529 #define SQLITE3_TEXT     3
4530 
4531 /*
4532 ** CAPI3REF: Result Values From A Query
4533 ** KEYWORDS: {column access functions}
4534 ** METHOD: sqlite3_stmt
4535 **
4536 ** <b>Summary:</b>
4537 ** <blockquote><table border=0 cellpadding=0 cellspacing=0>
4538 ** <tr><td><b>sqlite3_column_blob</b><td>&rarr;<td>BLOB result
4539 ** <tr><td><b>sqlite3_column_double</b><td>&rarr;<td>REAL result
4540 ** <tr><td><b>sqlite3_column_int</b><td>&rarr;<td>32-bit INTEGER result
4541 ** <tr><td><b>sqlite3_column_int64</b><td>&rarr;<td>64-bit INTEGER result
4542 ** <tr><td><b>sqlite3_column_text</b><td>&rarr;<td>UTF-8 TEXT result
4543 ** <tr><td><b>sqlite3_column_text16</b><td>&rarr;<td>UTF-16 TEXT result
4544 ** <tr><td><b>sqlite3_column_value</b><td>&rarr;<td>The result as an
4545 ** [sqlite3_value|unprotected sqlite3_value] object.
4546 ** <tr><td>&nbsp;<td>&nbsp;<td>&nbsp;
4547 ** <tr><td><b>sqlite3_column_bytes</b><td>&rarr;<td>Size of a BLOB
4548 ** or a UTF-8 TEXT result in bytes
4549 ** <tr><td><b>sqlite3_column_bytes16&nbsp;&nbsp;</b>
4550 ** <td>&rarr;&nbsp;&nbsp;<td>Size of UTF-16
4551 ** TEXT in bytes
4552 ** <tr><td><b>sqlite3_column_type</b><td>&rarr;<td>Default
4553 ** datatype of the result
4554 ** </table></blockquote>
4555 **
4556 ** <b>Details:</b>
4557 **
4558 ** ^These routines return information about a single column of the current
4559 ** result row of a query.  ^In every case the first argument is a pointer
4560 ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
4561 ** that was returned from [sqlite3_prepare_v2()] or one of its variants)
4562 ** and the second argument is the index of the column for which information
4563 ** should be returned. ^The leftmost column of the result set has the index 0.
4564 ** ^The number of columns in the result can be determined using
4565 ** [sqlite3_column_count()].
4566 **
4567 ** If the SQL statement does not currently point to a valid row, or if the
4568 ** column index is out of range, the result is undefined.
4569 ** These routines may only be called when the most recent call to
4570 ** [sqlite3_step()] has returned [SQLITE_ROW] and neither
4571 ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
4572 ** If any of these routines are called after [sqlite3_reset()] or
4573 ** [sqlite3_finalize()] or after [sqlite3_step()] has returned
4574 ** something other than [SQLITE_ROW], the results are undefined.
4575 ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
4576 ** are called from a different thread while any of these routines
4577 ** are pending, then the results are undefined.
4578 **
4579 ** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16)
4580 ** each return the value of a result column in a specific data format.  If
4581 ** the result column is not initially in the requested format (for example,
4582 ** if the query returns an integer but the sqlite3_column_text() interface
4583 ** is used to extract the value) then an automatic type conversion is performed.
4584 **
4585 ** ^The sqlite3_column_type() routine returns the
4586 ** [SQLITE_INTEGER | datatype code] for the initial data type
4587 ** of the result column.  ^The returned value is one of [SQLITE_INTEGER],
4588 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].
4589 ** The return value of sqlite3_column_type() can be used to decide which
4590 ** of the first six interface should be used to extract the column value.
4591 ** The value returned by sqlite3_column_type() is only meaningful if no
4592 ** automatic type conversions have occurred for the value in question.
4593 ** After a type conversion, the result of calling sqlite3_column_type()
4594 ** is undefined, though harmless.  Future
4595 ** versions of SQLite may change the behavior of sqlite3_column_type()
4596 ** following a type conversion.
4597 **
4598 ** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes()
4599 ** or sqlite3_column_bytes16() interfaces can be used to determine the size
4600 ** of that BLOB or string.
4601 **
4602 ** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
4603 ** routine returns the number of bytes in that BLOB or string.
4604 ** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
4605 ** the string to UTF-8 and then returns the number of bytes.
4606 ** ^If the result is a numeric value then sqlite3_column_bytes() uses
4607 ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
4608 ** the number of bytes in that string.
4609 ** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
4610 **
4611 ** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
4612 ** routine returns the number of bytes in that BLOB or string.
4613 ** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
4614 ** the string to UTF-16 and then returns the number of bytes.
4615 ** ^If the result is a numeric value then sqlite3_column_bytes16() uses
4616 ** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
4617 ** the number of bytes in that string.
4618 ** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
4619 **
4620 ** ^The values returned by [sqlite3_column_bytes()] and
4621 ** [sqlite3_column_bytes16()] do not include the zero terminators at the end
4622 ** of the string.  ^For clarity: the values returned by
4623 ** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
4624 ** bytes in the string, not the number of characters.
4625 **
4626 ** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
4627 ** even empty strings, are always zero-terminated.  ^The return
4628 ** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
4629 **
4630 ** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an
4631 ** [unprotected sqlite3_value] object.  In a multithreaded environment,
4632 ** an unprotected sqlite3_value object may only be used safely with
4633 ** [sqlite3_bind_value()] and [sqlite3_result_value()].
4634 ** If the [unprotected sqlite3_value] object returned by
4635 ** [sqlite3_column_value()] is used in any other way, including calls
4636 ** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
4637 ** or [sqlite3_value_bytes()], the behavior is not threadsafe.
4638 ** Hence, the sqlite3_column_value() interface
4639 ** is normally only useful within the implementation of
4640 ** [application-defined SQL functions] or [virtual tables], not within
4641 ** top-level application code.
4642 **
4643 ** The these routines may attempt to convert the datatype of the result.
4644 ** ^For example, if the internal representation is FLOAT and a text result
4645 ** is requested, [sqlite3_snprintf()] is used internally to perform the
4646 ** conversion automatically.  ^(The following table details the conversions
4647 ** that are applied:
4648 **
4649 ** <blockquote>
4650 ** <table border="1">
4651 ** <tr><th> Internal<br>Type <th> Requested<br>Type <th>  Conversion
4652 **
4653 ** <tr><td>  NULL    <td> INTEGER   <td> Result is 0
4654 ** <tr><td>  NULL    <td>  FLOAT    <td> Result is 0.0
4655 ** <tr><td>  NULL    <td>   TEXT    <td> Result is a NULL pointer
4656 ** <tr><td>  NULL    <td>   BLOB    <td> Result is a NULL pointer
4657 ** <tr><td> INTEGER  <td>  FLOAT    <td> Convert from integer to float
4658 ** <tr><td> INTEGER  <td>   TEXT    <td> ASCII rendering of the integer
4659 ** <tr><td> INTEGER  <td>   BLOB    <td> Same as INTEGER->TEXT
4660 ** <tr><td>  FLOAT   <td> INTEGER   <td> [CAST] to INTEGER
4661 ** <tr><td>  FLOAT   <td>   TEXT    <td> ASCII rendering of the float
4662 ** <tr><td>  FLOAT   <td>   BLOB    <td> [CAST] to BLOB
4663 ** <tr><td>  TEXT    <td> INTEGER   <td> [CAST] to INTEGER
4664 ** <tr><td>  TEXT    <td>  FLOAT    <td> [CAST] to REAL
4665 ** <tr><td>  TEXT    <td>   BLOB    <td> No change
4666 ** <tr><td>  BLOB    <td> INTEGER   <td> [CAST] to INTEGER
4667 ** <tr><td>  BLOB    <td>  FLOAT    <td> [CAST] to REAL
4668 ** <tr><td>  BLOB    <td>   TEXT    <td> Add a zero terminator if needed
4669 ** </table>
4670 ** </blockquote>)^
4671 **
4672 ** Note that when type conversions occur, pointers returned by prior
4673 ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
4674 ** sqlite3_column_text16() may be invalidated.
4675 ** Type conversions and pointer invalidations might occur
4676 ** in the following cases:
4677 **
4678 ** <ul>
4679 ** <li> The initial content is a BLOB and sqlite3_column_text() or
4680 **      sqlite3_column_text16() is called.  A zero-terminator might
4681 **      need to be added to the string.</li>
4682 ** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
4683 **      sqlite3_column_text16() is called.  The content must be converted
4684 **      to UTF-16.</li>
4685 ** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
4686 **      sqlite3_column_text() is called.  The content must be converted
4687 **      to UTF-8.</li>
4688 ** </ul>
4689 **
4690 ** ^Conversions between UTF-16be and UTF-16le are always done in place and do
4691 ** not invalidate a prior pointer, though of course the content of the buffer
4692 ** that the prior pointer references will have been modified.  Other kinds
4693 ** of conversion are done in place when it is possible, but sometimes they
4694 ** are not possible and in those cases prior pointers are invalidated.
4695 **
4696 ** The safest policy is to invoke these routines
4697 ** in one of the following ways:
4698 **
4699 ** <ul>
4700 **  <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
4701 **  <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
4702 **  <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
4703 ** </ul>
4704 **
4705 ** In other words, you should call sqlite3_column_text(),
4706 ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
4707 ** into the desired format, then invoke sqlite3_column_bytes() or
4708 ** sqlite3_column_bytes16() to find the size of the result.  Do not mix calls
4709 ** to sqlite3_column_text() or sqlite3_column_blob() with calls to
4710 ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
4711 ** with calls to sqlite3_column_bytes().
4712 **
4713 ** ^The pointers returned are valid until a type conversion occurs as
4714 ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
4715 ** [sqlite3_finalize()] is called.  ^The memory space used to hold strings
4716 ** and BLOBs is freed automatically.  Do not pass the pointers returned
4717 ** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
4718 ** [sqlite3_free()].
4719 **
4720 ** As long as the input parameters are correct, these routines will only
4721 ** fail if an out-of-memory error occurs during a format conversion.
4722 ** Only the following subset of interfaces are subject to out-of-memory
4723 ** errors:
4724 **
4725 ** <ul>
4726 ** <li> sqlite3_column_blob()
4727 ** <li> sqlite3_column_text()
4728 ** <li> sqlite3_column_text16()
4729 ** <li> sqlite3_column_bytes()
4730 ** <li> sqlite3_column_bytes16()
4731 ** </ul>
4732 **
4733 ** If an out-of-memory error occurs, then the return value from these
4734 ** routines is the same as if the column had contained an SQL NULL value.
4735 ** Valid SQL NULL returns can be distinguished from out-of-memory errors
4736 ** by invoking the [sqlite3_errcode()] immediately after the suspect
4737 ** return value is obtained and before any
4738 ** other SQLite interface is called on the same [database connection].
4739 */
4740 SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
4741 SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol);
4742 SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol);
4743 SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
4744 SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
4745 SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
4746 SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
4747 SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
4748 SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
4749 SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol);
4750 
4751 /*
4752 ** CAPI3REF: Destroy A Prepared Statement Object
4753 ** DESTRUCTOR: sqlite3_stmt
4754 **
4755 ** ^The sqlite3_finalize() function is called to delete a [prepared statement].
4756 ** ^If the most recent evaluation of the statement encountered no errors
4757 ** or if the statement is never been evaluated, then sqlite3_finalize() returns
4758 ** SQLITE_OK.  ^If the most recent evaluation of statement S failed, then
4759 ** sqlite3_finalize(S) returns the appropriate [error code] or
4760 ** [extended error code].
4761 **
4762 ** ^The sqlite3_finalize(S) routine can be called at any point during
4763 ** the life cycle of [prepared statement] S:
4764 ** before statement S is ever evaluated, after
4765 ** one or more calls to [sqlite3_reset()], or after any call
4766 ** to [sqlite3_step()] regardless of whether or not the statement has
4767 ** completed execution.
4768 **
4769 ** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
4770 **
4771 ** The application must finalize every [prepared statement] in order to avoid
4772 ** resource leaks.  It is a grievous error for the application to try to use
4773 ** a prepared statement after it has been finalized.  Any use of a prepared
4774 ** statement after it has been finalized can result in undefined and
4775 ** undesirable behavior such as segfaults and heap corruption.
4776 */
4777 SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt);
4778 
4779 /*
4780 ** CAPI3REF: Reset A Prepared Statement Object
4781 ** METHOD: sqlite3_stmt
4782 **
4783 ** The sqlite3_reset() function is called to reset a [prepared statement]
4784 ** object back to its initial state, ready to be re-executed.
4785 ** ^Any SQL statement variables that had values bound to them using
4786 ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
4787 ** Use [sqlite3_clear_bindings()] to reset the bindings.
4788 **
4789 ** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
4790 ** back to the beginning of its program.
4791 **
4792 ** ^If the most recent call to [sqlite3_step(S)] for the
4793 ** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
4794 ** or if [sqlite3_step(S)] has never before been called on S,
4795 ** then [sqlite3_reset(S)] returns [SQLITE_OK].
4796 **
4797 ** ^If the most recent call to [sqlite3_step(S)] for the
4798 ** [prepared statement] S indicated an error, then
4799 ** [sqlite3_reset(S)] returns an appropriate [error code].
4800 **
4801 ** ^The [sqlite3_reset(S)] interface does not change the values
4802 ** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
4803 */
4804 SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt);
4805 
4806 /*
4807 ** CAPI3REF: Create Or Redefine SQL Functions
4808 ** KEYWORDS: {function creation routines}
4809 ** KEYWORDS: {application-defined SQL function}
4810 ** KEYWORDS: {application-defined SQL functions}
4811 ** METHOD: sqlite3
4812 **
4813 ** ^These functions (collectively known as "function creation routines")
4814 ** are used to add SQL functions or aggregates or to redefine the behavior
4815 ** of existing SQL functions or aggregates. The only differences between
4816 ** the three "sqlite3_create_function*" routines are the text encoding
4817 ** expected for the second parameter (the name of the function being
4818 ** created) and the presence or absence of a destructor callback for
4819 ** the application data pointer. Function sqlite3_create_window_function()
4820 ** is similar, but allows the user to supply the extra callback functions
4821 ** needed by [aggregate window functions].
4822 **
4823 ** ^The first parameter is the [database connection] to which the SQL
4824 ** function is to be added.  ^If an application uses more than one database
4825 ** connection then application-defined SQL functions must be added
4826 ** to each database connection separately.
4827 **
4828 ** ^The second parameter is the name of the SQL function to be created or
4829 ** redefined.  ^The length of the name is limited to 255 bytes in a UTF-8
4830 ** representation, exclusive of the zero-terminator.  ^Note that the name
4831 ** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
4832 ** ^Any attempt to create a function with a longer name
4833 ** will result in [SQLITE_MISUSE] being returned.
4834 **
4835 ** ^The third parameter (nArg)
4836 ** is the number of arguments that the SQL function or
4837 ** aggregate takes. ^If this parameter is -1, then the SQL function or
4838 ** aggregate may take any number of arguments between 0 and the limit
4839 ** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]).  If the third
4840 ** parameter is less than -1 or greater than 127 then the behavior is
4841 ** undefined.
4842 **
4843 ** ^The fourth parameter, eTextRep, specifies what
4844 ** [SQLITE_UTF8 | text encoding] this SQL function prefers for
4845 ** its parameters.  The application should set this parameter to
4846 ** [SQLITE_UTF16LE] if the function implementation invokes
4847 ** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the
4848 ** implementation invokes [sqlite3_value_text16be()] on an input, or
4849 ** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8]
4850 ** otherwise.  ^The same SQL function may be registered multiple times using
4851 ** different preferred text encodings, with different implementations for
4852 ** each encoding.
4853 ** ^When multiple implementations of the same function are available, SQLite
4854 ** will pick the one that involves the least amount of data conversion.
4855 **
4856 ** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC]
4857 ** to signal that the function will always return the same result given
4858 ** the same inputs within a single SQL statement.  Most SQL functions are
4859 ** deterministic.  The built-in [random()] SQL function is an example of a
4860 ** function that is not deterministic.  The SQLite query planner is able to
4861 ** perform additional optimizations on deterministic functions, so use
4862 ** of the [SQLITE_DETERMINISTIC] flag is recommended where possible.
4863 **
4864 ** ^The fourth parameter may also optionally include the [SQLITE_DIRECTONLY]
4865 ** flag, which if present prevents the function from being invoked from
4866 ** within VIEWs or TRIGGERs.  For security reasons, the [SQLITE_DIRECTONLY]
4867 ** flag is recommended for any application-defined SQL function that has
4868 ** side-effects.
4869 **
4870 ** ^(The fifth parameter is an arbitrary pointer.  The implementation of the
4871 ** function can gain access to this pointer using [sqlite3_user_data()].)^
4872 **
4873 ** ^The sixth, seventh and eighth parameters passed to the three
4874 ** "sqlite3_create_function*" functions, xFunc, xStep and xFinal, are
4875 ** pointers to C-language functions that implement the SQL function or
4876 ** aggregate. ^A scalar SQL function requires an implementation of the xFunc
4877 ** callback only; NULL pointers must be passed as the xStep and xFinal
4878 ** parameters. ^An aggregate SQL function requires an implementation of xStep
4879 ** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
4880 ** SQL function or aggregate, pass NULL pointers for all three function
4881 ** callbacks.
4882 **
4883 ** ^The sixth, seventh, eighth and ninth parameters (xStep, xFinal, xValue
4884 ** and xInverse) passed to sqlite3_create_window_function are pointers to
4885 ** C-language callbacks that implement the new function. xStep and xFinal
4886 ** must both be non-NULL. xValue and xInverse may either both be NULL, in
4887 ** which case a regular aggregate function is created, or must both be
4888 ** non-NULL, in which case the new function may be used as either an aggregate
4889 ** or aggregate window function. More details regarding the implementation
4890 ** of aggregate window functions are
4891 ** [user-defined window functions|available here].
4892 **
4893 ** ^(If the final parameter to sqlite3_create_function_v2() or
4894 ** sqlite3_create_window_function() is not NULL, then it is destructor for
4895 ** the application data pointer. The destructor is invoked when the function
4896 ** is deleted, either by being overloaded or when the database connection
4897 ** closes.)^ ^The destructor is also invoked if the call to
4898 ** sqlite3_create_function_v2() fails.  ^When the destructor callback is
4899 ** invoked, it is passed a single argument which is a copy of the application
4900 ** data pointer which was the fifth parameter to sqlite3_create_function_v2().
4901 **
4902 ** ^It is permitted to register multiple implementations of the same
4903 ** functions with the same name but with either differing numbers of
4904 ** arguments or differing preferred text encodings.  ^SQLite will use
4905 ** the implementation that most closely matches the way in which the
4906 ** SQL function is used.  ^A function implementation with a non-negative
4907 ** nArg parameter is a better match than a function implementation with
4908 ** a negative nArg.  ^A function where the preferred text encoding
4909 ** matches the database encoding is a better
4910 ** match than a function where the encoding is different.
4911 ** ^A function where the encoding difference is between UTF16le and UTF16be
4912 ** is a closer match than a function where the encoding difference is
4913 ** between UTF8 and UTF16.
4914 **
4915 ** ^Built-in functions may be overloaded by new application-defined functions.
4916 **
4917 ** ^An application-defined function is permitted to call other
4918 ** SQLite interfaces.  However, such calls must not
4919 ** close the database connection nor finalize or reset the prepared
4920 ** statement in which the function is running.
4921 */
4922 SQLITE_API int sqlite3_create_function(
4923   sqlite3 *db,
4924   const char *zFunctionName,
4925   int nArg,
4926   int eTextRep,
4927   void *pApp,
4928   void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4929   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4930   void (*xFinal)(sqlite3_context*)
4931 );
4932 SQLITE_API int sqlite3_create_function16(
4933   sqlite3 *db,
4934   const void *zFunctionName,
4935   int nArg,
4936   int eTextRep,
4937   void *pApp,
4938   void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4939   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4940   void (*xFinal)(sqlite3_context*)
4941 );
4942 SQLITE_API int sqlite3_create_function_v2(
4943   sqlite3 *db,
4944   const char *zFunctionName,
4945   int nArg,
4946   int eTextRep,
4947   void *pApp,
4948   void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4949   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4950   void (*xFinal)(sqlite3_context*),
4951   void(*xDestroy)(void*)
4952 );
4953 SQLITE_API int sqlite3_create_window_function(
4954   sqlite3 *db,
4955   const char *zFunctionName,
4956   int nArg,
4957   int eTextRep,
4958   void *pApp,
4959   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4960   void (*xFinal)(sqlite3_context*),
4961   void (*xValue)(sqlite3_context*),
4962   void (*xInverse)(sqlite3_context*,int,sqlite3_value**),
4963   void(*xDestroy)(void*)
4964 );
4965 
4966 /*
4967 ** CAPI3REF: Text Encodings
4968 **
4969 ** These constant define integer codes that represent the various
4970 ** text encodings supported by SQLite.
4971 */
4972 #define SQLITE_UTF8           1    /* IMP: R-37514-35566 */
4973 #define SQLITE_UTF16LE        2    /* IMP: R-03371-37637 */
4974 #define SQLITE_UTF16BE        3    /* IMP: R-51971-34154 */
4975 #define SQLITE_UTF16          4    /* Use native byte order */
4976 #define SQLITE_ANY            5    /* Deprecated */
4977 #define SQLITE_UTF16_ALIGNED  8    /* sqlite3_create_collation only */
4978 
4979 /*
4980 ** CAPI3REF: Function Flags
4981 **
4982 ** These constants may be ORed together with the
4983 ** [SQLITE_UTF8 | preferred text encoding] as the fourth argument
4984 ** to [sqlite3_create_function()], [sqlite3_create_function16()], or
4985 ** [sqlite3_create_function_v2()].
4986 **
4987 ** The SQLITE_DETERMINISTIC flag means that the new function will always
4988 ** maps the same inputs into the same output.  The abs() function is
4989 ** deterministic, for example, but randomblob() is not.
4990 **
4991 ** The SQLITE_DIRECTONLY flag means that the function may only be invoked
4992 ** from top-level SQL, and cannot be used in VIEWs or TRIGGERs.  This is
4993 ** a security feature which is recommended for all
4994 ** [application-defined SQL functions] that have side-effects.  This flag
4995 ** prevents an attacker from adding triggers and views to a schema then
4996 ** tricking a high-privilege application into causing unintended side-effects
4997 ** while performing ordinary queries.
4998 **
4999 ** The SQLITE_SUBTYPE flag indicates to SQLite that a function may call
5000 ** [sqlite3_value_subtype()] to inspect the sub-types of its arguments.
5001 ** Specifying this flag makes no difference for scalar or aggregate user
5002 ** functions. However, if it is not specified for a user-defined window
5003 ** function, then any sub-types belonging to arguments passed to the window
5004 ** function may be discarded before the window function is called (i.e.
5005 ** sqlite3_value_subtype() will always return 0).
5006 */
5007 #define SQLITE_DETERMINISTIC    0x000000800
5008 #define SQLITE_DIRECTONLY       0x000080000
5009 #define SQLITE_SUBTYPE          0x000100000
5010 
5011 /*
5012 ** CAPI3REF: Deprecated Functions
5013 ** DEPRECATED
5014 **
5015 ** These functions are [deprecated].  In order to maintain
5016 ** backwards compatibility with older code, these functions continue
5017 ** to be supported.  However, new applications should avoid
5018 ** the use of these functions.  To encourage programmers to avoid
5019 ** these functions, we will not explain what they do.
5020 */
5021 #ifndef SQLITE_OMIT_DEPRECATED
5022 SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
5023 SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
5024 SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
5025 SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void);
5026 SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
5027 SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),
5028                       void*,sqlite3_int64);
5029 #endif
5030 
5031 /*
5032 ** CAPI3REF: Obtaining SQL Values
5033 ** METHOD: sqlite3_value
5034 **
5035 ** <b>Summary:</b>
5036 ** <blockquote><table border=0 cellpadding=0 cellspacing=0>
5037 ** <tr><td><b>sqlite3_value_blob</b><td>&rarr;<td>BLOB value
5038 ** <tr><td><b>sqlite3_value_double</b><td>&rarr;<td>REAL value
5039 ** <tr><td><b>sqlite3_value_int</b><td>&rarr;<td>32-bit INTEGER value
5040 ** <tr><td><b>sqlite3_value_int64</b><td>&rarr;<td>64-bit INTEGER value
5041 ** <tr><td><b>sqlite3_value_pointer</b><td>&rarr;<td>Pointer value
5042 ** <tr><td><b>sqlite3_value_text</b><td>&rarr;<td>UTF-8 TEXT value
5043 ** <tr><td><b>sqlite3_value_text16</b><td>&rarr;<td>UTF-16 TEXT value in
5044 ** the native byteorder
5045 ** <tr><td><b>sqlite3_value_text16be</b><td>&rarr;<td>UTF-16be TEXT value
5046 ** <tr><td><b>sqlite3_value_text16le</b><td>&rarr;<td>UTF-16le TEXT value
5047 ** <tr><td>&nbsp;<td>&nbsp;<td>&nbsp;
5048 ** <tr><td><b>sqlite3_value_bytes</b><td>&rarr;<td>Size of a BLOB
5049 ** or a UTF-8 TEXT in bytes
5050 ** <tr><td><b>sqlite3_value_bytes16&nbsp;&nbsp;</b>
5051 ** <td>&rarr;&nbsp;&nbsp;<td>Size of UTF-16
5052 ** TEXT in bytes
5053 ** <tr><td><b>sqlite3_value_type</b><td>&rarr;<td>Default
5054 ** datatype of the value
5055 ** <tr><td><b>sqlite3_value_numeric_type&nbsp;&nbsp;</b>
5056 ** <td>&rarr;&nbsp;&nbsp;<td>Best numeric datatype of the value
5057 ** <tr><td><b>sqlite3_value_nochange&nbsp;&nbsp;</b>
5058 ** <td>&rarr;&nbsp;&nbsp;<td>True if the column is unchanged in an UPDATE
5059 ** against a virtual table.
5060 ** <tr><td><b>sqlite3_value_frombind&nbsp;&nbsp;</b>
5061 ** <td>&rarr;&nbsp;&nbsp;<td>True if value originated from a [bound parameter]
5062 ** </table></blockquote>
5063 **
5064 ** <b>Details:</b>
5065 **
5066 ** These routines extract type, size, and content information from
5067 ** [protected sqlite3_value] objects.  Protected sqlite3_value objects
5068 ** are used to pass parameter information into implementation of
5069 ** [application-defined SQL functions] and [virtual tables].
5070 **
5071 ** These routines work only with [protected sqlite3_value] objects.
5072 ** Any attempt to use these routines on an [unprotected sqlite3_value]
5073 ** is not threadsafe.
5074 **
5075 ** ^These routines work just like the corresponding [column access functions]
5076 ** except that these routines take a single [protected sqlite3_value] object
5077 ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
5078 **
5079 ** ^The sqlite3_value_text16() interface extracts a UTF-16 string
5080 ** in the native byte-order of the host machine.  ^The
5081 ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
5082 ** extract UTF-16 strings as big-endian and little-endian respectively.
5083 **
5084 ** ^If [sqlite3_value] object V was initialized
5085 ** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)]
5086 ** and if X and Y are strings that compare equal according to strcmp(X,Y),
5087 ** then sqlite3_value_pointer(V,Y) will return the pointer P.  ^Otherwise,
5088 ** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer()
5089 ** routine is part of the [pointer passing interface] added for SQLite 3.20.0.
5090 **
5091 ** ^(The sqlite3_value_type(V) interface returns the
5092 ** [SQLITE_INTEGER | datatype code] for the initial datatype of the
5093 ** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER],
5094 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^
5095 ** Other interfaces might change the datatype for an sqlite3_value object.
5096 ** For example, if the datatype is initially SQLITE_INTEGER and
5097 ** sqlite3_value_text(V) is called to extract a text value for that
5098 ** integer, then subsequent calls to sqlite3_value_type(V) might return
5099 ** SQLITE_TEXT.  Whether or not a persistent internal datatype conversion
5100 ** occurs is undefined and may change from one release of SQLite to the next.
5101 **
5102 ** ^(The sqlite3_value_numeric_type() interface attempts to apply
5103 ** numeric affinity to the value.  This means that an attempt is
5104 ** made to convert the value to an integer or floating point.  If
5105 ** such a conversion is possible without loss of information (in other
5106 ** words, if the value is a string that looks like a number)
5107 ** then the conversion is performed.  Otherwise no conversion occurs.
5108 ** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
5109 **
5110 ** ^Within the [xUpdate] method of a [virtual table], the
5111 ** sqlite3_value_nochange(X) interface returns true if and only if
5112 ** the column corresponding to X is unchanged by the UPDATE operation
5113 ** that the xUpdate method call was invoked to implement and if
5114 ** and the prior [xColumn] method call that was invoked to extracted
5115 ** the value for that column returned without setting a result (probably
5116 ** because it queried [sqlite3_vtab_nochange()] and found that the column
5117 ** was unchanging).  ^Within an [xUpdate] method, any value for which
5118 ** sqlite3_value_nochange(X) is true will in all other respects appear
5119 ** to be a NULL value.  If sqlite3_value_nochange(X) is invoked anywhere other
5120 ** than within an [xUpdate] method call for an UPDATE statement, then
5121 ** the return value is arbitrary and meaningless.
5122 **
5123 ** ^The sqlite3_value_frombind(X) interface returns non-zero if the
5124 ** value X originated from one of the [sqlite3_bind_int|sqlite3_bind()]
5125 ** interfaces.  ^If X comes from an SQL literal value, or a table column,
5126 ** and expression, then sqlite3_value_frombind(X) returns zero.
5127 **
5128 ** Please pay particular attention to the fact that the pointer returned
5129 ** from [sqlite3_value_blob()], [sqlite3_value_text()], or
5130 ** [sqlite3_value_text16()] can be invalidated by a subsequent call to
5131 ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
5132 ** or [sqlite3_value_text16()].
5133 **
5134 ** These routines must be called from the same thread as
5135 ** the SQL function that supplied the [sqlite3_value*] parameters.
5136 **
5137 ** As long as the input parameter is correct, these routines can only
5138 ** fail if an out-of-memory error occurs during a format conversion.
5139 ** Only the following subset of interfaces are subject to out-of-memory
5140 ** errors:
5141 **
5142 ** <ul>
5143 ** <li> sqlite3_value_blob()
5144 ** <li> sqlite3_value_text()
5145 ** <li> sqlite3_value_text16()
5146 ** <li> sqlite3_value_text16le()
5147 ** <li> sqlite3_value_text16be()
5148 ** <li> sqlite3_value_bytes()
5149 ** <li> sqlite3_value_bytes16()
5150 ** </ul>
5151 **
5152 ** If an out-of-memory error occurs, then the return value from these
5153 ** routines is the same as if the column had contained an SQL NULL value.
5154 ** Valid SQL NULL returns can be distinguished from out-of-memory errors
5155 ** by invoking the [sqlite3_errcode()] immediately after the suspect
5156 ** return value is obtained and before any
5157 ** other SQLite interface is called on the same [database connection].
5158 */
5159 SQLITE_API const void *sqlite3_value_blob(sqlite3_value*);
5160 SQLITE_API double sqlite3_value_double(sqlite3_value*);
5161 SQLITE_API int sqlite3_value_int(sqlite3_value*);
5162 SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
5163 SQLITE_API void *sqlite3_value_pointer(sqlite3_value*, const char*);
5164 SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*);
5165 SQLITE_API const void *sqlite3_value_text16(sqlite3_value*);
5166 SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*);
5167 SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*);
5168 SQLITE_API int sqlite3_value_bytes(sqlite3_value*);
5169 SQLITE_API int sqlite3_value_bytes16(sqlite3_value*);
5170 SQLITE_API int sqlite3_value_type(sqlite3_value*);
5171 SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*);
5172 SQLITE_API int sqlite3_value_nochange(sqlite3_value*);
5173 SQLITE_API int sqlite3_value_frombind(sqlite3_value*);
5174 
5175 /*
5176 ** CAPI3REF: Finding The Subtype Of SQL Values
5177 ** METHOD: sqlite3_value
5178 **
5179 ** The sqlite3_value_subtype(V) function returns the subtype for
5180 ** an [application-defined SQL function] argument V.  The subtype
5181 ** information can be used to pass a limited amount of context from
5182 ** one SQL function to another.  Use the [sqlite3_result_subtype()]
5183 ** routine to set the subtype for the return value of an SQL function.
5184 */
5185 SQLITE_API unsigned int sqlite3_value_subtype(sqlite3_value*);
5186 
5187 /*
5188 ** CAPI3REF: Copy And Free SQL Values
5189 ** METHOD: sqlite3_value
5190 **
5191 ** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value]
5192 ** object D and returns a pointer to that copy.  ^The [sqlite3_value] returned
5193 ** is a [protected sqlite3_value] object even if the input is not.
5194 ** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a
5195 ** memory allocation fails.
5196 **
5197 ** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object
5198 ** previously obtained from [sqlite3_value_dup()].  ^If V is a NULL pointer
5199 ** then sqlite3_value_free(V) is a harmless no-op.
5200 */
5201 SQLITE_API sqlite3_value *sqlite3_value_dup(const sqlite3_value*);
5202 SQLITE_API void sqlite3_value_free(sqlite3_value*);
5203 
5204 /*
5205 ** CAPI3REF: Obtain Aggregate Function Context
5206 ** METHOD: sqlite3_context
5207 **
5208 ** Implementations of aggregate SQL functions use this
5209 ** routine to allocate memory for storing their state.
5210 **
5211 ** ^The first time the sqlite3_aggregate_context(C,N) routine is called
5212 ** for a particular aggregate function, SQLite
5213 ** allocates N of memory, zeroes out that memory, and returns a pointer
5214 ** to the new memory. ^On second and subsequent calls to
5215 ** sqlite3_aggregate_context() for the same aggregate function instance,
5216 ** the same buffer is returned.  Sqlite3_aggregate_context() is normally
5217 ** called once for each invocation of the xStep callback and then one
5218 ** last time when the xFinal callback is invoked.  ^(When no rows match
5219 ** an aggregate query, the xStep() callback of the aggregate function
5220 ** implementation is never called and xFinal() is called exactly once.
5221 ** In those cases, sqlite3_aggregate_context() might be called for the
5222 ** first time from within xFinal().)^
5223 **
5224 ** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer
5225 ** when first called if N is less than or equal to zero or if a memory
5226 ** allocate error occurs.
5227 **
5228 ** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
5229 ** determined by the N parameter on first successful call.  Changing the
5230 ** value of N in subsequent call to sqlite3_aggregate_context() within
5231 ** the same aggregate function instance will not resize the memory
5232 ** allocation.)^  Within the xFinal callback, it is customary to set
5233 ** N=0 in calls to sqlite3_aggregate_context(C,N) so that no
5234 ** pointless memory allocations occur.
5235 **
5236 ** ^SQLite automatically frees the memory allocated by
5237 ** sqlite3_aggregate_context() when the aggregate query concludes.
5238 **
5239 ** The first parameter must be a copy of the
5240 ** [sqlite3_context | SQL function context] that is the first parameter
5241 ** to the xStep or xFinal callback routine that implements the aggregate
5242 ** function.
5243 **
5244 ** This routine must be called from the same thread in which
5245 ** the aggregate SQL function is running.
5246 */
5247 SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
5248 
5249 /*
5250 ** CAPI3REF: User Data For Functions
5251 ** METHOD: sqlite3_context
5252 **
5253 ** ^The sqlite3_user_data() interface returns a copy of
5254 ** the pointer that was the pUserData parameter (the 5th parameter)
5255 ** of the [sqlite3_create_function()]
5256 ** and [sqlite3_create_function16()] routines that originally
5257 ** registered the application defined function.
5258 **
5259 ** This routine must be called from the same thread in which
5260 ** the application-defined function is running.
5261 */
5262 SQLITE_API void *sqlite3_user_data(sqlite3_context*);
5263 
5264 /*
5265 ** CAPI3REF: Database Connection For Functions
5266 ** METHOD: sqlite3_context
5267 **
5268 ** ^The sqlite3_context_db_handle() interface returns a copy of
5269 ** the pointer to the [database connection] (the 1st parameter)
5270 ** of the [sqlite3_create_function()]
5271 ** and [sqlite3_create_function16()] routines that originally
5272 ** registered the application defined function.
5273 */
5274 SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
5275 
5276 /*
5277 ** CAPI3REF: Function Auxiliary Data
5278 ** METHOD: sqlite3_context
5279 **
5280 ** These functions may be used by (non-aggregate) SQL functions to
5281 ** associate metadata with argument values. If the same value is passed to
5282 ** multiple invocations of the same SQL function during query execution, under
5283 ** some circumstances the associated metadata may be preserved.  An example
5284 ** of where this might be useful is in a regular-expression matching
5285 ** function. The compiled version of the regular expression can be stored as
5286 ** metadata associated with the pattern string.
5287 ** Then as long as the pattern string remains the same,
5288 ** the compiled regular expression can be reused on multiple
5289 ** invocations of the same function.
5290 **
5291 ** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the metadata
5292 ** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument
5293 ** value to the application-defined function.  ^N is zero for the left-most
5294 ** function argument.  ^If there is no metadata
5295 ** associated with the function argument, the sqlite3_get_auxdata(C,N) interface
5296 ** returns a NULL pointer.
5297 **
5298 ** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th
5299 ** argument of the application-defined function.  ^Subsequent
5300 ** calls to sqlite3_get_auxdata(C,N) return P from the most recent
5301 ** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or
5302 ** NULL if the metadata has been discarded.
5303 ** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL,
5304 ** SQLite will invoke the destructor function X with parameter P exactly
5305 ** once, when the metadata is discarded.
5306 ** SQLite is free to discard the metadata at any time, including: <ul>
5307 ** <li> ^(when the corresponding function parameter changes)^, or
5308 ** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the
5309 **      SQL statement)^, or
5310 ** <li> ^(when sqlite3_set_auxdata() is invoked again on the same
5311 **       parameter)^, or
5312 ** <li> ^(during the original sqlite3_set_auxdata() call when a memory
5313 **      allocation error occurs.)^ </ul>
5314 **
5315 ** Note the last bullet in particular.  The destructor X in
5316 ** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the
5317 ** sqlite3_set_auxdata() interface even returns.  Hence sqlite3_set_auxdata()
5318 ** should be called near the end of the function implementation and the
5319 ** function implementation should not make any use of P after
5320 ** sqlite3_set_auxdata() has been called.
5321 **
5322 ** ^(In practice, metadata is preserved between function calls for
5323 ** function parameters that are compile-time constants, including literal
5324 ** values and [parameters] and expressions composed from the same.)^
5325 **
5326 ** The value of the N parameter to these interfaces should be non-negative.
5327 ** Future enhancements may make use of negative N values to define new
5328 ** kinds of function caching behavior.
5329 **
5330 ** These routines must be called from the same thread in which
5331 ** the SQL function is running.
5332 */
5333 SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N);
5334 SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
5335 
5336 
5337 /*
5338 ** CAPI3REF: Constants Defining Special Destructor Behavior
5339 **
5340 ** These are special values for the destructor that is passed in as the
5341 ** final argument to routines like [sqlite3_result_blob()].  ^If the destructor
5342 ** argument is SQLITE_STATIC, it means that the content pointer is constant
5343 ** and will never change.  It does not need to be destroyed.  ^The
5344 ** SQLITE_TRANSIENT value means that the content will likely change in
5345 ** the near future and that SQLite should make its own private copy of
5346 ** the content before returning.
5347 **
5348 ** The typedef is necessary to work around problems in certain
5349 ** C++ compilers.
5350 */
5351 typedef void (*sqlite3_destructor_type)(void*);
5352 #define SQLITE_STATIC      ((sqlite3_destructor_type)0)
5353 #define SQLITE_TRANSIENT   ((sqlite3_destructor_type)-1)
5354 
5355 /*
5356 ** CAPI3REF: Setting The Result Of An SQL Function
5357 ** METHOD: sqlite3_context
5358 **
5359 ** These routines are used by the xFunc or xFinal callbacks that
5360 ** implement SQL functions and aggregates.  See
5361 ** [sqlite3_create_function()] and [sqlite3_create_function16()]
5362 ** for additional information.
5363 **
5364 ** These functions work very much like the [parameter binding] family of
5365 ** functions used to bind values to host parameters in prepared statements.
5366 ** Refer to the [SQL parameter] documentation for additional information.
5367 **
5368 ** ^The sqlite3_result_blob() interface sets the result from
5369 ** an application-defined function to be the BLOB whose content is pointed
5370 ** to by the second parameter and which is N bytes long where N is the
5371 ** third parameter.
5372 **
5373 ** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N)
5374 ** interfaces set the result of the application-defined function to be
5375 ** a BLOB containing all zero bytes and N bytes in size.
5376 **
5377 ** ^The sqlite3_result_double() interface sets the result from
5378 ** an application-defined function to be a floating point value specified
5379 ** by its 2nd argument.
5380 **
5381 ** ^The sqlite3_result_error() and sqlite3_result_error16() functions
5382 ** cause the implemented SQL function to throw an exception.
5383 ** ^SQLite uses the string pointed to by the
5384 ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
5385 ** as the text of an error message.  ^SQLite interprets the error
5386 ** message string from sqlite3_result_error() as UTF-8. ^SQLite
5387 ** interprets the string from sqlite3_result_error16() as UTF-16 in native
5388 ** byte order.  ^If the third parameter to sqlite3_result_error()
5389 ** or sqlite3_result_error16() is negative then SQLite takes as the error
5390 ** message all text up through the first zero character.
5391 ** ^If the third parameter to sqlite3_result_error() or
5392 ** sqlite3_result_error16() is non-negative then SQLite takes that many
5393 ** bytes (not characters) from the 2nd parameter as the error message.
5394 ** ^The sqlite3_result_error() and sqlite3_result_error16()
5395 ** routines make a private copy of the error message text before
5396 ** they return.  Hence, the calling function can deallocate or
5397 ** modify the text after they return without harm.
5398 ** ^The sqlite3_result_error_code() function changes the error code
5399 ** returned by SQLite as a result of an error in a function.  ^By default,
5400 ** the error code is SQLITE_ERROR.  ^A subsequent call to sqlite3_result_error()
5401 ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
5402 **
5403 ** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an
5404 ** error indicating that a string or BLOB is too long to represent.
5405 **
5406 ** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an
5407 ** error indicating that a memory allocation failed.
5408 **
5409 ** ^The sqlite3_result_int() interface sets the return value
5410 ** of the application-defined function to be the 32-bit signed integer
5411 ** value given in the 2nd argument.
5412 ** ^The sqlite3_result_int64() interface sets the return value
5413 ** of the application-defined function to be the 64-bit signed integer
5414 ** value given in the 2nd argument.
5415 **
5416 ** ^The sqlite3_result_null() interface sets the return value
5417 ** of the application-defined function to be NULL.
5418 **
5419 ** ^The sqlite3_result_text(), sqlite3_result_text16(),
5420 ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
5421 ** set the return value of the application-defined function to be
5422 ** a text string which is represented as UTF-8, UTF-16 native byte order,
5423 ** UTF-16 little endian, or UTF-16 big endian, respectively.
5424 ** ^The sqlite3_result_text64() interface sets the return value of an
5425 ** application-defined function to be a text string in an encoding
5426 ** specified by the fifth (and last) parameter, which must be one
5427 ** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE].
5428 ** ^SQLite takes the text result from the application from
5429 ** the 2nd parameter of the sqlite3_result_text* interfaces.
5430 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
5431 ** is negative, then SQLite takes result text from the 2nd parameter
5432 ** through the first zero character.
5433 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
5434 ** is non-negative, then as many bytes (not characters) of the text
5435 ** pointed to by the 2nd parameter are taken as the application-defined
5436 ** function result.  If the 3rd parameter is non-negative, then it
5437 ** must be the byte offset into the string where the NUL terminator would
5438 ** appear if the string where NUL terminated.  If any NUL characters occur
5439 ** in the string at a byte offset that is less than the value of the 3rd
5440 ** parameter, then the resulting string will contain embedded NULs and the
5441 ** result of expressions operating on strings with embedded NULs is undefined.
5442 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
5443 ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
5444 ** function as the destructor on the text or BLOB result when it has
5445 ** finished using that result.
5446 ** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
5447 ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
5448 ** assumes that the text or BLOB result is in constant space and does not
5449 ** copy the content of the parameter nor call a destructor on the content
5450 ** when it has finished using that result.
5451 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
5452 ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
5453 ** then SQLite makes a copy of the result into space obtained
5454 ** from [sqlite3_malloc()] before it returns.
5455 **
5456 ** ^The sqlite3_result_value() interface sets the result of
5457 ** the application-defined function to be a copy of the
5458 ** [unprotected sqlite3_value] object specified by the 2nd parameter.  ^The
5459 ** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
5460 ** so that the [sqlite3_value] specified in the parameter may change or
5461 ** be deallocated after sqlite3_result_value() returns without harm.
5462 ** ^A [protected sqlite3_value] object may always be used where an
5463 ** [unprotected sqlite3_value] object is required, so either
5464 ** kind of [sqlite3_value] object can be used with this interface.
5465 **
5466 ** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an
5467 ** SQL NULL value, just like [sqlite3_result_null(C)], except that it
5468 ** also associates the host-language pointer P or type T with that
5469 ** NULL value such that the pointer can be retrieved within an
5470 ** [application-defined SQL function] using [sqlite3_value_pointer()].
5471 ** ^If the D parameter is not NULL, then it is a pointer to a destructor
5472 ** for the P parameter.  ^SQLite invokes D with P as its only argument
5473 ** when SQLite is finished with P.  The T parameter should be a static
5474 ** string and preferably a string literal. The sqlite3_result_pointer()
5475 ** routine is part of the [pointer passing interface] added for SQLite 3.20.0.
5476 **
5477 ** If these routines are called from within the different thread
5478 ** than the one containing the application-defined function that received
5479 ** the [sqlite3_context] pointer, the results are undefined.
5480 */
5481 SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
5482 SQLITE_API void sqlite3_result_blob64(sqlite3_context*,const void*,
5483                            sqlite3_uint64,void(*)(void*));
5484 SQLITE_API void sqlite3_result_double(sqlite3_context*, double);
5485 SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int);
5486 SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int);
5487 SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*);
5488 SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*);
5489 SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int);
5490 SQLITE_API void sqlite3_result_int(sqlite3_context*, int);
5491 SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
5492 SQLITE_API void sqlite3_result_null(sqlite3_context*);
5493 SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
5494 SQLITE_API void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64,
5495                            void(*)(void*), unsigned char encoding);
5496 SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
5497 SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
5498 SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
5499 SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
5500 SQLITE_API void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*));
5501 SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n);
5502 SQLITE_API int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n);
5503 
5504 
5505 /*
5506 ** CAPI3REF: Setting The Subtype Of An SQL Function
5507 ** METHOD: sqlite3_context
5508 **
5509 ** The sqlite3_result_subtype(C,T) function causes the subtype of
5510 ** the result from the [application-defined SQL function] with
5511 ** [sqlite3_context] C to be the value T.  Only the lower 8 bits
5512 ** of the subtype T are preserved in current versions of SQLite;
5513 ** higher order bits are discarded.
5514 ** The number of subtype bytes preserved by SQLite might increase
5515 ** in future releases of SQLite.
5516 */
5517 SQLITE_API void sqlite3_result_subtype(sqlite3_context*,unsigned int);
5518 
5519 /*
5520 ** CAPI3REF: Define New Collating Sequences
5521 ** METHOD: sqlite3
5522 **
5523 ** ^These functions add, remove, or modify a [collation] associated
5524 ** with the [database connection] specified as the first argument.
5525 **
5526 ** ^The name of the collation is a UTF-8 string
5527 ** for sqlite3_create_collation() and sqlite3_create_collation_v2()
5528 ** and a UTF-16 string in native byte order for sqlite3_create_collation16().
5529 ** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
5530 ** considered to be the same name.
5531 **
5532 ** ^(The third argument (eTextRep) must be one of the constants:
5533 ** <ul>
5534 ** <li> [SQLITE_UTF8],
5535 ** <li> [SQLITE_UTF16LE],
5536 ** <li> [SQLITE_UTF16BE],
5537 ** <li> [SQLITE_UTF16], or
5538 ** <li> [SQLITE_UTF16_ALIGNED].
5539 ** </ul>)^
5540 ** ^The eTextRep argument determines the encoding of strings passed
5541 ** to the collating function callback, xCallback.
5542 ** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
5543 ** force strings to be UTF16 with native byte order.
5544 ** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
5545 ** on an even byte address.
5546 **
5547 ** ^The fourth argument, pArg, is an application data pointer that is passed
5548 ** through as the first argument to the collating function callback.
5549 **
5550 ** ^The fifth argument, xCallback, is a pointer to the collating function.
5551 ** ^Multiple collating functions can be registered using the same name but
5552 ** with different eTextRep parameters and SQLite will use whichever
5553 ** function requires the least amount of data transformation.
5554 ** ^If the xCallback argument is NULL then the collating function is
5555 ** deleted.  ^When all collating functions having the same name are deleted,
5556 ** that collation is no longer usable.
5557 **
5558 ** ^The collating function callback is invoked with a copy of the pArg
5559 ** application data pointer and with two strings in the encoding specified
5560 ** by the eTextRep argument.  The collating function must return an
5561 ** integer that is negative, zero, or positive
5562 ** if the first string is less than, equal to, or greater than the second,
5563 ** respectively.  A collating function must always return the same answer
5564 ** given the same inputs.  If two or more collating functions are registered
5565 ** to the same collation name (using different eTextRep values) then all
5566 ** must give an equivalent answer when invoked with equivalent strings.
5567 ** The collating function must obey the following properties for all
5568 ** strings A, B, and C:
5569 **
5570 ** <ol>
5571 ** <li> If A==B then B==A.
5572 ** <li> If A==B and B==C then A==C.
5573 ** <li> If A&lt;B THEN B&gt;A.
5574 ** <li> If A&lt;B and B&lt;C then A&lt;C.
5575 ** </ol>
5576 **
5577 ** If a collating function fails any of the above constraints and that
5578 ** collating function is  registered and used, then the behavior of SQLite
5579 ** is undefined.
5580 **
5581 ** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
5582 ** with the addition that the xDestroy callback is invoked on pArg when
5583 ** the collating function is deleted.
5584 ** ^Collating functions are deleted when they are overridden by later
5585 ** calls to the collation creation functions or when the
5586 ** [database connection] is closed using [sqlite3_close()].
5587 **
5588 ** ^The xDestroy callback is <u>not</u> called if the
5589 ** sqlite3_create_collation_v2() function fails.  Applications that invoke
5590 ** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
5591 ** check the return code and dispose of the application data pointer
5592 ** themselves rather than expecting SQLite to deal with it for them.
5593 ** This is different from every other SQLite interface.  The inconsistency
5594 ** is unfortunate but cannot be changed without breaking backwards
5595 ** compatibility.
5596 **
5597 ** See also:  [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
5598 */
5599 SQLITE_API int sqlite3_create_collation(
5600   sqlite3*,
5601   const char *zName,
5602   int eTextRep,
5603   void *pArg,
5604   int(*xCompare)(void*,int,const void*,int,const void*)
5605 );
5606 SQLITE_API int sqlite3_create_collation_v2(
5607   sqlite3*,
5608   const char *zName,
5609   int eTextRep,
5610   void *pArg,
5611   int(*xCompare)(void*,int,const void*,int,const void*),
5612   void(*xDestroy)(void*)
5613 );
5614 SQLITE_API int sqlite3_create_collation16(
5615   sqlite3*,
5616   const void *zName,
5617   int eTextRep,
5618   void *pArg,
5619   int(*xCompare)(void*,int,const void*,int,const void*)
5620 );
5621 
5622 /*
5623 ** CAPI3REF: Collation Needed Callbacks
5624 ** METHOD: sqlite3
5625 **
5626 ** ^To avoid having to register all collation sequences before a database
5627 ** can be used, a single callback function may be registered with the
5628 ** [database connection] to be invoked whenever an undefined collation
5629 ** sequence is required.
5630 **
5631 ** ^If the function is registered using the sqlite3_collation_needed() API,
5632 ** then it is passed the names of undefined collation sequences as strings
5633 ** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
5634 ** the names are passed as UTF-16 in machine native byte order.
5635 ** ^A call to either function replaces the existing collation-needed callback.
5636 **
5637 ** ^(When the callback is invoked, the first argument passed is a copy
5638 ** of the second argument to sqlite3_collation_needed() or
5639 ** sqlite3_collation_needed16().  The second argument is the database
5640 ** connection.  The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
5641 ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
5642 ** sequence function required.  The fourth parameter is the name of the
5643 ** required collation sequence.)^
5644 **
5645 ** The callback function should register the desired collation using
5646 ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
5647 ** [sqlite3_create_collation_v2()].
5648 */
5649 SQLITE_API int sqlite3_collation_needed(
5650   sqlite3*,
5651   void*,
5652   void(*)(void*,sqlite3*,int eTextRep,const char*)
5653 );
5654 SQLITE_API int sqlite3_collation_needed16(
5655   sqlite3*,
5656   void*,
5657   void(*)(void*,sqlite3*,int eTextRep,const void*)
5658 );
5659 
5660 #ifdef SQLITE_HAS_CODEC
5661 /*
5662 ** Specify the key for an encrypted database.  This routine should be
5663 ** called right after sqlite3_open().
5664 **
5665 ** The code to implement this API is not available in the public release
5666 ** of SQLite.
5667 */
5668 SQLITE_API int sqlite3_key(
5669   sqlite3 *db,                   /* Database to be rekeyed */
5670   const void *pKey, int nKey     /* The key */
5671 );
5672 SQLITE_API int sqlite3_key_v2(
5673   sqlite3 *db,                   /* Database to be rekeyed */
5674   const char *zDbName,           /* Name of the database */
5675   const void *pKey, int nKey     /* The key */
5676 );
5677 
5678 /*
5679 ** Change the key on an open database.  If the current database is not
5680 ** encrypted, this routine will encrypt it.  If pNew==0 or nNew==0, the
5681 ** database is decrypted.
5682 **
5683 ** The code to implement this API is not available in the public release
5684 ** of SQLite.
5685 */
5686 SQLITE_API int sqlite3_rekey(
5687   sqlite3 *db,                   /* Database to be rekeyed */
5688   const void *pKey, int nKey     /* The new key */
5689 );
5690 SQLITE_API int sqlite3_rekey_v2(
5691   sqlite3 *db,                   /* Database to be rekeyed */
5692   const char *zDbName,           /* Name of the database */
5693   const void *pKey, int nKey     /* The new key */
5694 );
5695 
5696 /*
5697 ** Specify the activation key for a SEE database.  Unless
5698 ** activated, none of the SEE routines will work.
5699 */
5700 SQLITE_API void sqlite3_activate_see(
5701   const char *zPassPhrase        /* Activation phrase */
5702 );
5703 #endif
5704 
5705 #ifdef SQLITE_ENABLE_CEROD
5706 /*
5707 ** Specify the activation key for a CEROD database.  Unless
5708 ** activated, none of the CEROD routines will work.
5709 */
5710 SQLITE_API void sqlite3_activate_cerod(
5711   const char *zPassPhrase        /* Activation phrase */
5712 );
5713 #endif
5714 
5715 /*
5716 ** CAPI3REF: Suspend Execution For A Short Time
5717 **
5718 ** The sqlite3_sleep() function causes the current thread to suspend execution
5719 ** for at least a number of milliseconds specified in its parameter.
5720 **
5721 ** If the operating system does not support sleep requests with
5722 ** millisecond time resolution, then the time will be rounded up to
5723 ** the nearest second. The number of milliseconds of sleep actually
5724 ** requested from the operating system is returned.
5725 **
5726 ** ^SQLite implements this interface by calling the xSleep()
5727 ** method of the default [sqlite3_vfs] object.  If the xSleep() method
5728 ** of the default VFS is not implemented correctly, or not implemented at
5729 ** all, then the behavior of sqlite3_sleep() may deviate from the description
5730 ** in the previous paragraphs.
5731 */
5732 SQLITE_API int sqlite3_sleep(int);
5733 
5734 /*
5735 ** CAPI3REF: Name Of The Folder Holding Temporary Files
5736 **
5737 ** ^(If this global variable is made to point to a string which is
5738 ** the name of a folder (a.k.a. directory), then all temporary files
5739 ** created by SQLite when using a built-in [sqlite3_vfs | VFS]
5740 ** will be placed in that directory.)^  ^If this variable
5741 ** is a NULL pointer, then SQLite performs a search for an appropriate
5742 ** temporary file directory.
5743 **
5744 ** Applications are strongly discouraged from using this global variable.
5745 ** It is required to set a temporary folder on Windows Runtime (WinRT).
5746 ** But for all other platforms, it is highly recommended that applications
5747 ** neither read nor write this variable.  This global variable is a relic
5748 ** that exists for backwards compatibility of legacy applications and should
5749 ** be avoided in new projects.
5750 **
5751 ** It is not safe to read or modify this variable in more than one
5752 ** thread at a time.  It is not safe to read or modify this variable
5753 ** if a [database connection] is being used at the same time in a separate
5754 ** thread.
5755 ** It is intended that this variable be set once
5756 ** as part of process initialization and before any SQLite interface
5757 ** routines have been called and that this variable remain unchanged
5758 ** thereafter.
5759 **
5760 ** ^The [temp_store_directory pragma] may modify this variable and cause
5761 ** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
5762 ** the [temp_store_directory pragma] always assumes that any string
5763 ** that this variable points to is held in memory obtained from
5764 ** [sqlite3_malloc] and the pragma may attempt to free that memory
5765 ** using [sqlite3_free].
5766 ** Hence, if this variable is modified directly, either it should be
5767 ** made NULL or made to point to memory obtained from [sqlite3_malloc]
5768 ** or else the use of the [temp_store_directory pragma] should be avoided.
5769 ** Except when requested by the [temp_store_directory pragma], SQLite
5770 ** does not free the memory that sqlite3_temp_directory points to.  If
5771 ** the application wants that memory to be freed, it must do
5772 ** so itself, taking care to only do so after all [database connection]
5773 ** objects have been destroyed.
5774 **
5775 ** <b>Note to Windows Runtime users:</b>  The temporary directory must be set
5776 ** prior to calling [sqlite3_open] or [sqlite3_open_v2].  Otherwise, various
5777 ** features that require the use of temporary files may fail.  Here is an
5778 ** example of how to do this using C++ with the Windows Runtime:
5779 **
5780 ** <blockquote><pre>
5781 ** LPCWSTR zPath = Windows::Storage::ApplicationData::Current->
5782 ** &nbsp;     TemporaryFolder->Path->Data();
5783 ** char zPathBuf&#91;MAX_PATH + 1&#93;;
5784 ** memset(zPathBuf, 0, sizeof(zPathBuf));
5785 ** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),
5786 ** &nbsp;     NULL, NULL);
5787 ** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);
5788 ** </pre></blockquote>
5789 */
5790 SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory;
5791 
5792 /*
5793 ** CAPI3REF: Name Of The Folder Holding Database Files
5794 **
5795 ** ^(If this global variable is made to point to a string which is
5796 ** the name of a folder (a.k.a. directory), then all database files
5797 ** specified with a relative pathname and created or accessed by
5798 ** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed
5799 ** to be relative to that directory.)^ ^If this variable is a NULL
5800 ** pointer, then SQLite assumes that all database files specified
5801 ** with a relative pathname are relative to the current directory
5802 ** for the process.  Only the windows VFS makes use of this global
5803 ** variable; it is ignored by the unix VFS.
5804 **
5805 ** Changing the value of this variable while a database connection is
5806 ** open can result in a corrupt database.
5807 **
5808 ** It is not safe to read or modify this variable in more than one
5809 ** thread at a time.  It is not safe to read or modify this variable
5810 ** if a [database connection] is being used at the same time in a separate
5811 ** thread.
5812 ** It is intended that this variable be set once
5813 ** as part of process initialization and before any SQLite interface
5814 ** routines have been called and that this variable remain unchanged
5815 ** thereafter.
5816 **
5817 ** ^The [data_store_directory pragma] may modify this variable and cause
5818 ** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
5819 ** the [data_store_directory pragma] always assumes that any string
5820 ** that this variable points to is held in memory obtained from
5821 ** [sqlite3_malloc] and the pragma may attempt to free that memory
5822 ** using [sqlite3_free].
5823 ** Hence, if this variable is modified directly, either it should be
5824 ** made NULL or made to point to memory obtained from [sqlite3_malloc]
5825 ** or else the use of the [data_store_directory pragma] should be avoided.
5826 */
5827 SQLITE_API SQLITE_EXTERN char *sqlite3_data_directory;
5828 
5829 /*
5830 ** CAPI3REF: Win32 Specific Interface
5831 **
5832 ** These interfaces are available only on Windows.  The
5833 ** [sqlite3_win32_set_directory] interface is used to set the value associated
5834 ** with the [sqlite3_temp_directory] or [sqlite3_data_directory] variable, to
5835 ** zValue, depending on the value of the type parameter.  The zValue parameter
5836 ** should be NULL to cause the previous value to be freed via [sqlite3_free];
5837 ** a non-NULL value will be copied into memory obtained from [sqlite3_malloc]
5838 ** prior to being used.  The [sqlite3_win32_set_directory] interface returns
5839 ** [SQLITE_OK] to indicate success, [SQLITE_ERROR] if the type is unsupported,
5840 ** or [SQLITE_NOMEM] if memory could not be allocated.  The value of the
5841 ** [sqlite3_data_directory] variable is intended to act as a replacement for
5842 ** the current directory on the sub-platforms of Win32 where that concept is
5843 ** not present, e.g. WinRT and UWP.  The [sqlite3_win32_set_directory8] and
5844 ** [sqlite3_win32_set_directory16] interfaces behave exactly the same as the
5845 ** sqlite3_win32_set_directory interface except the string parameter must be
5846 ** UTF-8 or UTF-16, respectively.
5847 */
5848 SQLITE_API int sqlite3_win32_set_directory(
5849   unsigned long type, /* Identifier for directory being set or reset */
5850   void *zValue        /* New value for directory being set or reset */
5851 );
5852 SQLITE_API int sqlite3_win32_set_directory8(unsigned long type, const char *zValue);
5853 SQLITE_API int sqlite3_win32_set_directory16(unsigned long type, const void *zValue);
5854 
5855 /*
5856 ** CAPI3REF: Win32 Directory Types
5857 **
5858 ** These macros are only available on Windows.  They define the allowed values
5859 ** for the type argument to the [sqlite3_win32_set_directory] interface.
5860 */
5861 #define SQLITE_WIN32_DATA_DIRECTORY_TYPE  1
5862 #define SQLITE_WIN32_TEMP_DIRECTORY_TYPE  2
5863 
5864 /*
5865 ** CAPI3REF: Test For Auto-Commit Mode
5866 ** KEYWORDS: {autocommit mode}
5867 ** METHOD: sqlite3
5868 **
5869 ** ^The sqlite3_get_autocommit() interface returns non-zero or
5870 ** zero if the given database connection is or is not in autocommit mode,
5871 ** respectively.  ^Autocommit mode is on by default.
5872 ** ^Autocommit mode is disabled by a [BEGIN] statement.
5873 ** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
5874 **
5875 ** If certain kinds of errors occur on a statement within a multi-statement
5876 ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
5877 ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
5878 ** transaction might be rolled back automatically.  The only way to
5879 ** find out whether SQLite automatically rolled back the transaction after
5880 ** an error is to use this function.
5881 **
5882 ** If another thread changes the autocommit status of the database
5883 ** connection while this routine is running, then the return value
5884 ** is undefined.
5885 */
5886 SQLITE_API int sqlite3_get_autocommit(sqlite3*);
5887 
5888 /*
5889 ** CAPI3REF: Find The Database Handle Of A Prepared Statement
5890 ** METHOD: sqlite3_stmt
5891 **
5892 ** ^The sqlite3_db_handle interface returns the [database connection] handle
5893 ** to which a [prepared statement] belongs.  ^The [database connection]
5894 ** returned by sqlite3_db_handle is the same [database connection]
5895 ** that was the first argument
5896 ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
5897 ** create the statement in the first place.
5898 */
5899 SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
5900 
5901 /*
5902 ** CAPI3REF: Return The Filename For A Database Connection
5903 ** METHOD: sqlite3
5904 **
5905 ** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename
5906 ** associated with database N of connection D.  ^The main database file
5907 ** has the name "main".  If there is no attached database N on the database
5908 ** connection D, or if database N is a temporary or in-memory database, then
5909 ** this function will return either a NULL pointer or an empty string.
5910 **
5911 ** ^The filename returned by this function is the output of the
5912 ** xFullPathname method of the [VFS].  ^In other words, the filename
5913 ** will be an absolute pathname, even if the filename used
5914 ** to open the database originally was a URI or relative pathname.
5915 */
5916 SQLITE_API const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName);
5917 
5918 /*
5919 ** CAPI3REF: Determine if a database is read-only
5920 ** METHOD: sqlite3
5921 **
5922 ** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N
5923 ** of connection D is read-only, 0 if it is read/write, or -1 if N is not
5924 ** the name of a database on connection D.
5925 */
5926 SQLITE_API int sqlite3_db_readonly(sqlite3 *db, const char *zDbName);
5927 
5928 /*
5929 ** CAPI3REF: Find the next prepared statement
5930 ** METHOD: sqlite3
5931 **
5932 ** ^This interface returns a pointer to the next [prepared statement] after
5933 ** pStmt associated with the [database connection] pDb.  ^If pStmt is NULL
5934 ** then this interface returns a pointer to the first prepared statement
5935 ** associated with the database connection pDb.  ^If no prepared statement
5936 ** satisfies the conditions of this routine, it returns NULL.
5937 **
5938 ** The [database connection] pointer D in a call to
5939 ** [sqlite3_next_stmt(D,S)] must refer to an open database
5940 ** connection and in particular must not be a NULL pointer.
5941 */
5942 SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
5943 
5944 /*
5945 ** CAPI3REF: Commit And Rollback Notification Callbacks
5946 ** METHOD: sqlite3
5947 **
5948 ** ^The sqlite3_commit_hook() interface registers a callback
5949 ** function to be invoked whenever a transaction is [COMMIT | committed].
5950 ** ^Any callback set by a previous call to sqlite3_commit_hook()
5951 ** for the same database connection is overridden.
5952 ** ^The sqlite3_rollback_hook() interface registers a callback
5953 ** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
5954 ** ^Any callback set by a previous call to sqlite3_rollback_hook()
5955 ** for the same database connection is overridden.
5956 ** ^The pArg argument is passed through to the callback.
5957 ** ^If the callback on a commit hook function returns non-zero,
5958 ** then the commit is converted into a rollback.
5959 **
5960 ** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
5961 ** return the P argument from the previous call of the same function
5962 ** on the same [database connection] D, or NULL for
5963 ** the first call for each function on D.
5964 **
5965 ** The commit and rollback hook callbacks are not reentrant.
5966 ** The callback implementation must not do anything that will modify
5967 ** the database connection that invoked the callback.  Any actions
5968 ** to modify the database connection must be deferred until after the
5969 ** completion of the [sqlite3_step()] call that triggered the commit
5970 ** or rollback hook in the first place.
5971 ** Note that running any other SQL statements, including SELECT statements,
5972 ** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
5973 ** the database connections for the meaning of "modify" in this paragraph.
5974 **
5975 ** ^Registering a NULL function disables the callback.
5976 **
5977 ** ^When the commit hook callback routine returns zero, the [COMMIT]
5978 ** operation is allowed to continue normally.  ^If the commit hook
5979 ** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
5980 ** ^The rollback hook is invoked on a rollback that results from a commit
5981 ** hook returning non-zero, just as it would be with any other rollback.
5982 **
5983 ** ^For the purposes of this API, a transaction is said to have been
5984 ** rolled back if an explicit "ROLLBACK" statement is executed, or
5985 ** an error or constraint causes an implicit rollback to occur.
5986 ** ^The rollback callback is not invoked if a transaction is
5987 ** automatically rolled back because the database connection is closed.
5988 **
5989 ** See also the [sqlite3_update_hook()] interface.
5990 */
5991 SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
5992 SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
5993 
5994 /*
5995 ** CAPI3REF: Data Change Notification Callbacks
5996 ** METHOD: sqlite3
5997 **
5998 ** ^The sqlite3_update_hook() interface registers a callback function
5999 ** with the [database connection] identified by the first argument
6000 ** to be invoked whenever a row is updated, inserted or deleted in
6001 ** a [rowid table].
6002 ** ^Any callback set by a previous call to this function
6003 ** for the same database connection is overridden.
6004 **
6005 ** ^The second argument is a pointer to the function to invoke when a
6006 ** row is updated, inserted or deleted in a rowid table.
6007 ** ^The first argument to the callback is a copy of the third argument
6008 ** to sqlite3_update_hook().
6009 ** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
6010 ** or [SQLITE_UPDATE], depending on the operation that caused the callback
6011 ** to be invoked.
6012 ** ^The third and fourth arguments to the callback contain pointers to the
6013 ** database and table name containing the affected row.
6014 ** ^The final callback parameter is the [rowid] of the row.
6015 ** ^In the case of an update, this is the [rowid] after the update takes place.
6016 **
6017 ** ^(The update hook is not invoked when internal system tables are
6018 ** modified (i.e. sqlite_master and sqlite_sequence).)^
6019 ** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified.
6020 **
6021 ** ^In the current implementation, the update hook
6022 ** is not invoked when conflicting rows are deleted because of an
6023 ** [ON CONFLICT | ON CONFLICT REPLACE] clause.  ^Nor is the update hook
6024 ** invoked when rows are deleted using the [truncate optimization].
6025 ** The exceptions defined in this paragraph might change in a future
6026 ** release of SQLite.
6027 **
6028 ** The update hook implementation must not do anything that will modify
6029 ** the database connection that invoked the update hook.  Any actions
6030 ** to modify the database connection must be deferred until after the
6031 ** completion of the [sqlite3_step()] call that triggered the update hook.
6032 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
6033 ** database connections for the meaning of "modify" in this paragraph.
6034 **
6035 ** ^The sqlite3_update_hook(D,C,P) function
6036 ** returns the P argument from the previous call
6037 ** on the same [database connection] D, or NULL for
6038 ** the first call on D.
6039 **
6040 ** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()],
6041 ** and [sqlite3_preupdate_hook()] interfaces.
6042 */
6043 SQLITE_API void *sqlite3_update_hook(
6044   sqlite3*,
6045   void(*)(void *,int ,char const *,char const *,sqlite3_int64),
6046   void*
6047 );
6048 
6049 /*
6050 ** CAPI3REF: Enable Or Disable Shared Pager Cache
6051 **
6052 ** ^(This routine enables or disables the sharing of the database cache
6053 ** and schema data structures between [database connection | connections]
6054 ** to the same database. Sharing is enabled if the argument is true
6055 ** and disabled if the argument is false.)^
6056 **
6057 ** ^Cache sharing is enabled and disabled for an entire process.
6058 ** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]).
6059 ** In prior versions of SQLite,
6060 ** sharing was enabled or disabled for each thread separately.
6061 **
6062 ** ^(The cache sharing mode set by this interface effects all subsequent
6063 ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
6064 ** Existing database connections continue use the sharing mode
6065 ** that was in effect at the time they were opened.)^
6066 **
6067 ** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
6068 ** successfully.  An [error code] is returned otherwise.)^
6069 **
6070 ** ^Shared cache is disabled by default. But this might change in
6071 ** future releases of SQLite.  Applications that care about shared
6072 ** cache setting should set it explicitly.
6073 **
6074 ** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0
6075 ** and will always return SQLITE_MISUSE. On those systems,
6076 ** shared cache mode should be enabled per-database connection via
6077 ** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE].
6078 **
6079 ** This interface is threadsafe on processors where writing a
6080 ** 32-bit integer is atomic.
6081 **
6082 ** See Also:  [SQLite Shared-Cache Mode]
6083 */
6084 SQLITE_API int sqlite3_enable_shared_cache(int);
6085 
6086 /*
6087 ** CAPI3REF: Attempt To Free Heap Memory
6088 **
6089 ** ^The sqlite3_release_memory() interface attempts to free N bytes
6090 ** of heap memory by deallocating non-essential memory allocations
6091 ** held by the database library.   Memory used to cache database
6092 ** pages to improve performance is an example of non-essential memory.
6093 ** ^sqlite3_release_memory() returns the number of bytes actually freed,
6094 ** which might be more or less than the amount requested.
6095 ** ^The sqlite3_release_memory() routine is a no-op returning zero
6096 ** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
6097 **
6098 ** See also: [sqlite3_db_release_memory()]
6099 */
6100 SQLITE_API int sqlite3_release_memory(int);
6101 
6102 /*
6103 ** CAPI3REF: Free Memory Used By A Database Connection
6104 ** METHOD: sqlite3
6105 **
6106 ** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap
6107 ** memory as possible from database connection D. Unlike the
6108 ** [sqlite3_release_memory()] interface, this interface is in effect even
6109 ** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
6110 ** omitted.
6111 **
6112 ** See also: [sqlite3_release_memory()]
6113 */
6114 SQLITE_API int sqlite3_db_release_memory(sqlite3*);
6115 
6116 /*
6117 ** CAPI3REF: Impose A Limit On Heap Size
6118 **
6119 ** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
6120 ** soft limit on the amount of heap memory that may be allocated by SQLite.
6121 ** ^SQLite strives to keep heap memory utilization below the soft heap
6122 ** limit by reducing the number of pages held in the page cache
6123 ** as heap memory usages approaches the limit.
6124 ** ^The soft heap limit is "soft" because even though SQLite strives to stay
6125 ** below the limit, it will exceed the limit rather than generate
6126 ** an [SQLITE_NOMEM] error.  In other words, the soft heap limit
6127 ** is advisory only.
6128 **
6129 ** ^The return value from sqlite3_soft_heap_limit64() is the size of
6130 ** the soft heap limit prior to the call, or negative in the case of an
6131 ** error.  ^If the argument N is negative
6132 ** then no change is made to the soft heap limit.  Hence, the current
6133 ** size of the soft heap limit can be determined by invoking
6134 ** sqlite3_soft_heap_limit64() with a negative argument.
6135 **
6136 ** ^If the argument N is zero then the soft heap limit is disabled.
6137 **
6138 ** ^(The soft heap limit is not enforced in the current implementation
6139 ** if one or more of following conditions are true:
6140 **
6141 ** <ul>
6142 ** <li> The soft heap limit is set to zero.
6143 ** <li> Memory accounting is disabled using a combination of the
6144 **      [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
6145 **      the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
6146 ** <li> An alternative page cache implementation is specified using
6147 **      [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
6148 ** <li> The page cache allocates from its own memory pool supplied
6149 **      by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
6150 **      from the heap.
6151 ** </ul>)^
6152 **
6153 ** Beginning with SQLite [version 3.7.3] ([dateof:3.7.3]),
6154 ** the soft heap limit is enforced
6155 ** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT]
6156 ** compile-time option is invoked.  With [SQLITE_ENABLE_MEMORY_MANAGEMENT],
6157 ** the soft heap limit is enforced on every memory allocation.  Without
6158 ** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced
6159 ** when memory is allocated by the page cache.  Testing suggests that because
6160 ** the page cache is the predominate memory user in SQLite, most
6161 ** applications will achieve adequate soft heap limit enforcement without
6162 ** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT].
6163 **
6164 ** The circumstances under which SQLite will enforce the soft heap limit may
6165 ** changes in future releases of SQLite.
6166 */
6167 SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);
6168 
6169 /*
6170 ** CAPI3REF: Deprecated Soft Heap Limit Interface
6171 ** DEPRECATED
6172 **
6173 ** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
6174 ** interface.  This routine is provided for historical compatibility
6175 ** only.  All new applications should use the
6176 ** [sqlite3_soft_heap_limit64()] interface rather than this one.
6177 */
6178 SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N);
6179 
6180 
6181 /*
6182 ** CAPI3REF: Extract Metadata About A Column Of A Table
6183 ** METHOD: sqlite3
6184 **
6185 ** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns
6186 ** information about column C of table T in database D
6187 ** on [database connection] X.)^  ^The sqlite3_table_column_metadata()
6188 ** interface returns SQLITE_OK and fills in the non-NULL pointers in
6189 ** the final five arguments with appropriate values if the specified
6190 ** column exists.  ^The sqlite3_table_column_metadata() interface returns
6191 ** SQLITE_ERROR and if the specified column does not exist.
6192 ** ^If the column-name parameter to sqlite3_table_column_metadata() is a
6193 ** NULL pointer, then this routine simply checks for the existence of the
6194 ** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it
6195 ** does not.  If the table name parameter T in a call to
6196 ** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is
6197 ** undefined behavior.
6198 **
6199 ** ^The column is identified by the second, third and fourth parameters to
6200 ** this function. ^(The second parameter is either the name of the database
6201 ** (i.e. "main", "temp", or an attached database) containing the specified
6202 ** table or NULL.)^ ^If it is NULL, then all attached databases are searched
6203 ** for the table using the same algorithm used by the database engine to
6204 ** resolve unqualified table references.
6205 **
6206 ** ^The third and fourth parameters to this function are the table and column
6207 ** name of the desired column, respectively.
6208 **
6209 ** ^Metadata is returned by writing to the memory locations passed as the 5th
6210 ** and subsequent parameters to this function. ^Any of these arguments may be
6211 ** NULL, in which case the corresponding element of metadata is omitted.
6212 **
6213 ** ^(<blockquote>
6214 ** <table border="1">
6215 ** <tr><th> Parameter <th> Output<br>Type <th>  Description
6216 **
6217 ** <tr><td> 5th <td> const char* <td> Data type
6218 ** <tr><td> 6th <td> const char* <td> Name of default collation sequence
6219 ** <tr><td> 7th <td> int         <td> True if column has a NOT NULL constraint
6220 ** <tr><td> 8th <td> int         <td> True if column is part of the PRIMARY KEY
6221 ** <tr><td> 9th <td> int         <td> True if column is [AUTOINCREMENT]
6222 ** </table>
6223 ** </blockquote>)^
6224 **
6225 ** ^The memory pointed to by the character pointers returned for the
6226 ** declaration type and collation sequence is valid until the next
6227 ** call to any SQLite API function.
6228 **
6229 ** ^If the specified table is actually a view, an [error code] is returned.
6230 **
6231 ** ^If the specified column is "rowid", "oid" or "_rowid_" and the table
6232 ** is not a [WITHOUT ROWID] table and an
6233 ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
6234 ** parameters are set for the explicitly declared column. ^(If there is no
6235 ** [INTEGER PRIMARY KEY] column, then the outputs
6236 ** for the [rowid] are set as follows:
6237 **
6238 ** <pre>
6239 **     data type: "INTEGER"
6240 **     collation sequence: "BINARY"
6241 **     not null: 0
6242 **     primary key: 1
6243 **     auto increment: 0
6244 ** </pre>)^
6245 **
6246 ** ^This function causes all database schemas to be read from disk and
6247 ** parsed, if that has not already been done, and returns an error if
6248 ** any errors are encountered while loading the schema.
6249 */
6250 SQLITE_API int sqlite3_table_column_metadata(
6251   sqlite3 *db,                /* Connection handle */
6252   const char *zDbName,        /* Database name or NULL */
6253   const char *zTableName,     /* Table name */
6254   const char *zColumnName,    /* Column name */
6255   char const **pzDataType,    /* OUTPUT: Declared data type */
6256   char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
6257   int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
6258   int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
6259   int *pAutoinc               /* OUTPUT: True if column is auto-increment */
6260 );
6261 
6262 /*
6263 ** CAPI3REF: Load An Extension
6264 ** METHOD: sqlite3
6265 **
6266 ** ^This interface loads an SQLite extension library from the named file.
6267 **
6268 ** ^The sqlite3_load_extension() interface attempts to load an
6269 ** [SQLite extension] library contained in the file zFile.  If
6270 ** the file cannot be loaded directly, attempts are made to load
6271 ** with various operating-system specific extensions added.
6272 ** So for example, if "samplelib" cannot be loaded, then names like
6273 ** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might
6274 ** be tried also.
6275 **
6276 ** ^The entry point is zProc.
6277 ** ^(zProc may be 0, in which case SQLite will try to come up with an
6278 ** entry point name on its own.  It first tries "sqlite3_extension_init".
6279 ** If that does not work, it constructs a name "sqlite3_X_init" where the
6280 ** X is consists of the lower-case equivalent of all ASCII alphabetic
6281 ** characters in the filename from the last "/" to the first following
6282 ** "." and omitting any initial "lib".)^
6283 ** ^The sqlite3_load_extension() interface returns
6284 ** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
6285 ** ^If an error occurs and pzErrMsg is not 0, then the
6286 ** [sqlite3_load_extension()] interface shall attempt to
6287 ** fill *pzErrMsg with error message text stored in memory
6288 ** obtained from [sqlite3_malloc()]. The calling function
6289 ** should free this memory by calling [sqlite3_free()].
6290 **
6291 ** ^Extension loading must be enabled using
6292 ** [sqlite3_enable_load_extension()] or
6293 ** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL)
6294 ** prior to calling this API,
6295 ** otherwise an error will be returned.
6296 **
6297 ** <b>Security warning:</b> It is recommended that the
6298 ** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this
6299 ** interface.  The use of the [sqlite3_enable_load_extension()] interface
6300 ** should be avoided.  This will keep the SQL function [load_extension()]
6301 ** disabled and prevent SQL injections from giving attackers
6302 ** access to extension loading capabilities.
6303 **
6304 ** See also the [load_extension() SQL function].
6305 */
6306 SQLITE_API int sqlite3_load_extension(
6307   sqlite3 *db,          /* Load the extension into this database connection */
6308   const char *zFile,    /* Name of the shared library containing extension */
6309   const char *zProc,    /* Entry point.  Derived from zFile if 0 */
6310   char **pzErrMsg       /* Put error message here if not 0 */
6311 );
6312 
6313 /*
6314 ** CAPI3REF: Enable Or Disable Extension Loading
6315 ** METHOD: sqlite3
6316 **
6317 ** ^So as not to open security holes in older applications that are
6318 ** unprepared to deal with [extension loading], and as a means of disabling
6319 ** [extension loading] while evaluating user-entered SQL, the following API
6320 ** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
6321 **
6322 ** ^Extension loading is off by default.
6323 ** ^Call the sqlite3_enable_load_extension() routine with onoff==1
6324 ** to turn extension loading on and call it with onoff==0 to turn
6325 ** it back off again.
6326 **
6327 ** ^This interface enables or disables both the C-API
6328 ** [sqlite3_load_extension()] and the SQL function [load_extension()].
6329 ** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..)
6330 ** to enable or disable only the C-API.)^
6331 **
6332 ** <b>Security warning:</b> It is recommended that extension loading
6333 ** be disabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method
6334 ** rather than this interface, so the [load_extension()] SQL function
6335 ** remains disabled. This will prevent SQL injections from giving attackers
6336 ** access to extension loading capabilities.
6337 */
6338 SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
6339 
6340 /*
6341 ** CAPI3REF: Automatically Load Statically Linked Extensions
6342 **
6343 ** ^This interface causes the xEntryPoint() function to be invoked for
6344 ** each new [database connection] that is created.  The idea here is that
6345 ** xEntryPoint() is the entry point for a statically linked [SQLite extension]
6346 ** that is to be automatically loaded into all new database connections.
6347 **
6348 ** ^(Even though the function prototype shows that xEntryPoint() takes
6349 ** no arguments and returns void, SQLite invokes xEntryPoint() with three
6350 ** arguments and expects an integer result as if the signature of the
6351 ** entry point where as follows:
6352 **
6353 ** <blockquote><pre>
6354 ** &nbsp;  int xEntryPoint(
6355 ** &nbsp;    sqlite3 *db,
6356 ** &nbsp;    const char **pzErrMsg,
6357 ** &nbsp;    const struct sqlite3_api_routines *pThunk
6358 ** &nbsp;  );
6359 ** </pre></blockquote>)^
6360 **
6361 ** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
6362 ** point to an appropriate error message (obtained from [sqlite3_mprintf()])
6363 ** and return an appropriate [error code].  ^SQLite ensures that *pzErrMsg
6364 ** is NULL before calling the xEntryPoint().  ^SQLite will invoke
6365 ** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns.  ^If any
6366 ** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
6367 ** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
6368 **
6369 ** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
6370 ** on the list of automatic extensions is a harmless no-op. ^No entry point
6371 ** will be called more than once for each database connection that is opened.
6372 **
6373 ** See also: [sqlite3_reset_auto_extension()]
6374 ** and [sqlite3_cancel_auto_extension()]
6375 */
6376 SQLITE_API int sqlite3_auto_extension(void(*xEntryPoint)(void));
6377 
6378 /*
6379 ** CAPI3REF: Cancel Automatic Extension Loading
6380 **
6381 ** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the
6382 ** initialization routine X that was registered using a prior call to
6383 ** [sqlite3_auto_extension(X)].  ^The [sqlite3_cancel_auto_extension(X)]
6384 ** routine returns 1 if initialization routine X was successfully
6385 ** unregistered and it returns 0 if X was not on the list of initialization
6386 ** routines.
6387 */
6388 SQLITE_API int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void));
6389 
6390 /*
6391 ** CAPI3REF: Reset Automatic Extension Loading
6392 **
6393 ** ^This interface disables all automatic extensions previously
6394 ** registered using [sqlite3_auto_extension()].
6395 */
6396 SQLITE_API void sqlite3_reset_auto_extension(void);
6397 
6398 /*
6399 ** The interface to the virtual-table mechanism is currently considered
6400 ** to be experimental.  The interface might change in incompatible ways.
6401 ** If this is a problem for you, do not use the interface at this time.
6402 **
6403 ** When the virtual-table mechanism stabilizes, we will declare the
6404 ** interface fixed, support it indefinitely, and remove this comment.
6405 */
6406 
6407 /*
6408 ** Structures used by the virtual table interface
6409 */
6410 typedef struct sqlite3_vtab sqlite3_vtab;
6411 typedef struct sqlite3_index_info sqlite3_index_info;
6412 typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
6413 typedef struct sqlite3_module sqlite3_module;
6414 
6415 /*
6416 ** CAPI3REF: Virtual Table Object
6417 ** KEYWORDS: sqlite3_module {virtual table module}
6418 **
6419 ** This structure, sometimes called a "virtual table module",
6420 ** defines the implementation of a [virtual tables].
6421 ** This structure consists mostly of methods for the module.
6422 **
6423 ** ^A virtual table module is created by filling in a persistent
6424 ** instance of this structure and passing a pointer to that instance
6425 ** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
6426 ** ^The registration remains valid until it is replaced by a different
6427 ** module or until the [database connection] closes.  The content
6428 ** of this structure must not change while it is registered with
6429 ** any database connection.
6430 */
6431 struct sqlite3_module {
6432   int iVersion;
6433   int (*xCreate)(sqlite3*, void *pAux,
6434                int argc, const char *const*argv,
6435                sqlite3_vtab **ppVTab, char**);
6436   int (*xConnect)(sqlite3*, void *pAux,
6437                int argc, const char *const*argv,
6438                sqlite3_vtab **ppVTab, char**);
6439   int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
6440   int (*xDisconnect)(sqlite3_vtab *pVTab);
6441   int (*xDestroy)(sqlite3_vtab *pVTab);
6442   int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
6443   int (*xClose)(sqlite3_vtab_cursor*);
6444   int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
6445                 int argc, sqlite3_value **argv);
6446   int (*xNext)(sqlite3_vtab_cursor*);
6447   int (*xEof)(sqlite3_vtab_cursor*);
6448   int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
6449   int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
6450   int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
6451   int (*xBegin)(sqlite3_vtab *pVTab);
6452   int (*xSync)(sqlite3_vtab *pVTab);
6453   int (*xCommit)(sqlite3_vtab *pVTab);
6454   int (*xRollback)(sqlite3_vtab *pVTab);
6455   int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
6456                        void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
6457                        void **ppArg);
6458   int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
6459   /* The methods above are in version 1 of the sqlite_module object. Those
6460   ** below are for version 2 and greater. */
6461   int (*xSavepoint)(sqlite3_vtab *pVTab, int);
6462   int (*xRelease)(sqlite3_vtab *pVTab, int);
6463   int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
6464   /* The methods above are in versions 1 and 2 of the sqlite_module object.
6465   ** Those below are for version 3 and greater. */
6466   int (*xShadowName)(const char*);
6467 };
6468 
6469 /*
6470 ** CAPI3REF: Virtual Table Indexing Information
6471 ** KEYWORDS: sqlite3_index_info
6472 **
6473 ** The sqlite3_index_info structure and its substructures is used as part
6474 ** of the [virtual table] interface to
6475 ** pass information into and receive the reply from the [xBestIndex]
6476 ** method of a [virtual table module].  The fields under **Inputs** are the
6477 ** inputs to xBestIndex and are read-only.  xBestIndex inserts its
6478 ** results into the **Outputs** fields.
6479 **
6480 ** ^(The aConstraint[] array records WHERE clause constraints of the form:
6481 **
6482 ** <blockquote>column OP expr</blockquote>
6483 **
6484 ** where OP is =, &lt;, &lt;=, &gt;, or &gt;=.)^  ^(The particular operator is
6485 ** stored in aConstraint[].op using one of the
6486 ** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
6487 ** ^(The index of the column is stored in
6488 ** aConstraint[].iColumn.)^  ^(aConstraint[].usable is TRUE if the
6489 ** expr on the right-hand side can be evaluated (and thus the constraint
6490 ** is usable) and false if it cannot.)^
6491 **
6492 ** ^The optimizer automatically inverts terms of the form "expr OP column"
6493 ** and makes other simplifications to the WHERE clause in an attempt to
6494 ** get as many WHERE clause terms into the form shown above as possible.
6495 ** ^The aConstraint[] array only reports WHERE clause terms that are
6496 ** relevant to the particular virtual table being queried.
6497 **
6498 ** ^Information about the ORDER BY clause is stored in aOrderBy[].
6499 ** ^Each term of aOrderBy records a column of the ORDER BY clause.
6500 **
6501 ** The colUsed field indicates which columns of the virtual table may be
6502 ** required by the current scan. Virtual table columns are numbered from
6503 ** zero in the order in which they appear within the CREATE TABLE statement
6504 ** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62),
6505 ** the corresponding bit is set within the colUsed mask if the column may be
6506 ** required by SQLite. If the table has at least 64 columns and any column
6507 ** to the right of the first 63 is required, then bit 63 of colUsed is also
6508 ** set. In other words, column iCol may be required if the expression
6509 ** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to
6510 ** non-zero.
6511 **
6512 ** The [xBestIndex] method must fill aConstraintUsage[] with information
6513 ** about what parameters to pass to xFilter.  ^If argvIndex>0 then
6514 ** the right-hand side of the corresponding aConstraint[] is evaluated
6515 ** and becomes the argvIndex-th entry in argv.  ^(If aConstraintUsage[].omit
6516 ** is true, then the constraint is assumed to be fully handled by the
6517 ** virtual table and is not checked again by SQLite.)^
6518 **
6519 ** ^The idxNum and idxPtr values are recorded and passed into the
6520 ** [xFilter] method.
6521 ** ^[sqlite3_free()] is used to free idxPtr if and only if
6522 ** needToFreeIdxPtr is true.
6523 **
6524 ** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
6525 ** the correct order to satisfy the ORDER BY clause so that no separate
6526 ** sorting step is required.
6527 **
6528 ** ^The estimatedCost value is an estimate of the cost of a particular
6529 ** strategy. A cost of N indicates that the cost of the strategy is similar
6530 ** to a linear scan of an SQLite table with N rows. A cost of log(N)
6531 ** indicates that the expense of the operation is similar to that of a
6532 ** binary search on a unique indexed field of an SQLite table with N rows.
6533 **
6534 ** ^The estimatedRows value is an estimate of the number of rows that
6535 ** will be returned by the strategy.
6536 **
6537 ** The xBestIndex method may optionally populate the idxFlags field with a
6538 ** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag -
6539 ** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite
6540 ** assumes that the strategy may visit at most one row.
6541 **
6542 ** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then
6543 ** SQLite also assumes that if a call to the xUpdate() method is made as
6544 ** part of the same statement to delete or update a virtual table row and the
6545 ** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback
6546 ** any database changes. In other words, if the xUpdate() returns
6547 ** SQLITE_CONSTRAINT, the database contents must be exactly as they were
6548 ** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not
6549 ** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by
6550 ** the xUpdate method are automatically rolled back by SQLite.
6551 **
6552 ** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info
6553 ** structure for SQLite [version 3.8.2] ([dateof:3.8.2]).
6554 ** If a virtual table extension is
6555 ** used with an SQLite version earlier than 3.8.2, the results of attempting
6556 ** to read or write the estimatedRows field are undefined (but are likely
6557 ** to included crashing the application). The estimatedRows field should
6558 ** therefore only be used if [sqlite3_libversion_number()] returns a
6559 ** value greater than or equal to 3008002. Similarly, the idxFlags field
6560 ** was added for [version 3.9.0] ([dateof:3.9.0]).
6561 ** It may therefore only be used if
6562 ** sqlite3_libversion_number() returns a value greater than or equal to
6563 ** 3009000.
6564 */
6565 struct sqlite3_index_info {
6566   /* Inputs */
6567   int nConstraint;           /* Number of entries in aConstraint */
6568   struct sqlite3_index_constraint {
6569      int iColumn;              /* Column constrained.  -1 for ROWID */
6570      unsigned char op;         /* Constraint operator */
6571      unsigned char usable;     /* True if this constraint is usable */
6572      int iTermOffset;          /* Used internally - xBestIndex should ignore */
6573   } *aConstraint;            /* Table of WHERE clause constraints */
6574   int nOrderBy;              /* Number of terms in the ORDER BY clause */
6575   struct sqlite3_index_orderby {
6576      int iColumn;              /* Column number */
6577      unsigned char desc;       /* True for DESC.  False for ASC. */
6578   } *aOrderBy;               /* The ORDER BY clause */
6579   /* Outputs */
6580   struct sqlite3_index_constraint_usage {
6581     int argvIndex;           /* if >0, constraint is part of argv to xFilter */
6582     unsigned char omit;      /* Do not code a test for this constraint */
6583   } *aConstraintUsage;
6584   int idxNum;                /* Number used to identify the index */
6585   char *idxStr;              /* String, possibly obtained from sqlite3_malloc */
6586   int needToFreeIdxStr;      /* Free idxStr using sqlite3_free() if true */
6587   int orderByConsumed;       /* True if output is already ordered */
6588   double estimatedCost;           /* Estimated cost of using this index */
6589   /* Fields below are only available in SQLite 3.8.2 and later */
6590   sqlite3_int64 estimatedRows;    /* Estimated number of rows returned */
6591   /* Fields below are only available in SQLite 3.9.0 and later */
6592   int idxFlags;              /* Mask of SQLITE_INDEX_SCAN_* flags */
6593   /* Fields below are only available in SQLite 3.10.0 and later */
6594   sqlite3_uint64 colUsed;    /* Input: Mask of columns used by statement */
6595 };
6596 
6597 /*
6598 ** CAPI3REF: Virtual Table Scan Flags
6599 **
6600 ** Virtual table implementations are allowed to set the
6601 ** [sqlite3_index_info].idxFlags field to some combination of
6602 ** these bits.
6603 */
6604 #define SQLITE_INDEX_SCAN_UNIQUE      1     /* Scan visits at most 1 row */
6605 
6606 /*
6607 ** CAPI3REF: Virtual Table Constraint Operator Codes
6608 **
6609 ** These macros defined the allowed values for the
6610 ** [sqlite3_index_info].aConstraint[].op field.  Each value represents
6611 ** an operator that is part of a constraint term in the wHERE clause of
6612 ** a query that uses a [virtual table].
6613 */
6614 #define SQLITE_INDEX_CONSTRAINT_EQ         2
6615 #define SQLITE_INDEX_CONSTRAINT_GT         4
6616 #define SQLITE_INDEX_CONSTRAINT_LE         8
6617 #define SQLITE_INDEX_CONSTRAINT_LT        16
6618 #define SQLITE_INDEX_CONSTRAINT_GE        32
6619 #define SQLITE_INDEX_CONSTRAINT_MATCH     64
6620 #define SQLITE_INDEX_CONSTRAINT_LIKE      65
6621 #define SQLITE_INDEX_CONSTRAINT_GLOB      66
6622 #define SQLITE_INDEX_CONSTRAINT_REGEXP    67
6623 #define SQLITE_INDEX_CONSTRAINT_NE        68
6624 #define SQLITE_INDEX_CONSTRAINT_ISNOT     69
6625 #define SQLITE_INDEX_CONSTRAINT_ISNOTNULL 70
6626 #define SQLITE_INDEX_CONSTRAINT_ISNULL    71
6627 #define SQLITE_INDEX_CONSTRAINT_IS        72
6628 #define SQLITE_INDEX_CONSTRAINT_FUNCTION 150
6629 
6630 /*
6631 ** CAPI3REF: Register A Virtual Table Implementation
6632 ** METHOD: sqlite3
6633 **
6634 ** ^These routines are used to register a new [virtual table module] name.
6635 ** ^Module names must be registered before
6636 ** creating a new [virtual table] using the module and before using a
6637 ** preexisting [virtual table] for the module.
6638 **
6639 ** ^The module name is registered on the [database connection] specified
6640 ** by the first parameter.  ^The name of the module is given by the
6641 ** second parameter.  ^The third parameter is a pointer to
6642 ** the implementation of the [virtual table module].   ^The fourth
6643 ** parameter is an arbitrary client data pointer that is passed through
6644 ** into the [xCreate] and [xConnect] methods of the virtual table module
6645 ** when a new virtual table is be being created or reinitialized.
6646 **
6647 ** ^The sqlite3_create_module_v2() interface has a fifth parameter which
6648 ** is a pointer to a destructor for the pClientData.  ^SQLite will
6649 ** invoke the destructor function (if it is not NULL) when SQLite
6650 ** no longer needs the pClientData pointer.  ^The destructor will also
6651 ** be invoked if the call to sqlite3_create_module_v2() fails.
6652 ** ^The sqlite3_create_module()
6653 ** interface is equivalent to sqlite3_create_module_v2() with a NULL
6654 ** destructor.
6655 **
6656 ** ^If the third parameter (the pointer to the sqlite3_module object) is
6657 ** NULL then no new module is create and any existing modules with the
6658 ** same name are dropped.
6659 **
6660 ** See also: [sqlite3_drop_modules()]
6661 */
6662 SQLITE_API int sqlite3_create_module(
6663   sqlite3 *db,               /* SQLite connection to register module with */
6664   const char *zName,         /* Name of the module */
6665   const sqlite3_module *p,   /* Methods for the module */
6666   void *pClientData          /* Client data for xCreate/xConnect */
6667 );
6668 SQLITE_API int sqlite3_create_module_v2(
6669   sqlite3 *db,               /* SQLite connection to register module with */
6670   const char *zName,         /* Name of the module */
6671   const sqlite3_module *p,   /* Methods for the module */
6672   void *pClientData,         /* Client data for xCreate/xConnect */
6673   void(*xDestroy)(void*)     /* Module destructor function */
6674 );
6675 
6676 /*
6677 ** CAPI3REF: Remove Unnecessary Virtual Table Implementations
6678 ** METHOD: sqlite3
6679 **
6680 ** ^The sqlite3_drop_modules(D,L) interface removes all virtual
6681 ** table modules from database connection D except those named on list L.
6682 ** The L parameter must be either NULL or a pointer to an array of pointers
6683 ** to strings where the array is terminated by a single NULL pointer.
6684 ** ^If the L parameter is NULL, then all virtual table modules are removed.
6685 **
6686 ** See also: [sqlite3_create_module()]
6687 */
6688 SQLITE_API int sqlite3_drop_modules(
6689   sqlite3 *db,                /* Remove modules from this connection */
6690   const char **azKeep         /* Except, do not remove the ones named here */
6691 );
6692 
6693 /*
6694 ** CAPI3REF: Virtual Table Instance Object
6695 ** KEYWORDS: sqlite3_vtab
6696 **
6697 ** Every [virtual table module] implementation uses a subclass
6698 ** of this object to describe a particular instance
6699 ** of the [virtual table].  Each subclass will
6700 ** be tailored to the specific needs of the module implementation.
6701 ** The purpose of this superclass is to define certain fields that are
6702 ** common to all module implementations.
6703 **
6704 ** ^Virtual tables methods can set an error message by assigning a
6705 ** string obtained from [sqlite3_mprintf()] to zErrMsg.  The method should
6706 ** take care that any prior string is freed by a call to [sqlite3_free()]
6707 ** prior to assigning a new string to zErrMsg.  ^After the error message
6708 ** is delivered up to the client application, the string will be automatically
6709 ** freed by sqlite3_free() and the zErrMsg field will be zeroed.
6710 */
6711 struct sqlite3_vtab {
6712   const sqlite3_module *pModule;  /* The module for this virtual table */
6713   int nRef;                       /* Number of open cursors */
6714   char *zErrMsg;                  /* Error message from sqlite3_mprintf() */
6715   /* Virtual table implementations will typically add additional fields */
6716 };
6717 
6718 /*
6719 ** CAPI3REF: Virtual Table Cursor Object
6720 ** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
6721 **
6722 ** Every [virtual table module] implementation uses a subclass of the
6723 ** following structure to describe cursors that point into the
6724 ** [virtual table] and are used
6725 ** to loop through the virtual table.  Cursors are created using the
6726 ** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
6727 ** by the [sqlite3_module.xClose | xClose] method.  Cursors are used
6728 ** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
6729 ** of the module.  Each module implementation will define
6730 ** the content of a cursor structure to suit its own needs.
6731 **
6732 ** This superclass exists in order to define fields of the cursor that
6733 ** are common to all implementations.
6734 */
6735 struct sqlite3_vtab_cursor {
6736   sqlite3_vtab *pVtab;      /* Virtual table of this cursor */
6737   /* Virtual table implementations will typically add additional fields */
6738 };
6739 
6740 /*
6741 ** CAPI3REF: Declare The Schema Of A Virtual Table
6742 **
6743 ** ^The [xCreate] and [xConnect] methods of a
6744 ** [virtual table module] call this interface
6745 ** to declare the format (the names and datatypes of the columns) of
6746 ** the virtual tables they implement.
6747 */
6748 SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
6749 
6750 /*
6751 ** CAPI3REF: Overload A Function For A Virtual Table
6752 ** METHOD: sqlite3
6753 **
6754 ** ^(Virtual tables can provide alternative implementations of functions
6755 ** using the [xFindFunction] method of the [virtual table module].
6756 ** But global versions of those functions
6757 ** must exist in order to be overloaded.)^
6758 **
6759 ** ^(This API makes sure a global version of a function with a particular
6760 ** name and number of parameters exists.  If no such function exists
6761 ** before this API is called, a new function is created.)^  ^The implementation
6762 ** of the new function always causes an exception to be thrown.  So
6763 ** the new function is not good for anything by itself.  Its only
6764 ** purpose is to be a placeholder function that can be overloaded
6765 ** by a [virtual table].
6766 */
6767 SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
6768 
6769 /*
6770 ** The interface to the virtual-table mechanism defined above (back up
6771 ** to a comment remarkably similar to this one) is currently considered
6772 ** to be experimental.  The interface might change in incompatible ways.
6773 ** If this is a problem for you, do not use the interface at this time.
6774 **
6775 ** When the virtual-table mechanism stabilizes, we will declare the
6776 ** interface fixed, support it indefinitely, and remove this comment.
6777 */
6778 
6779 /*
6780 ** CAPI3REF: A Handle To An Open BLOB
6781 ** KEYWORDS: {BLOB handle} {BLOB handles}
6782 **
6783 ** An instance of this object represents an open BLOB on which
6784 ** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
6785 ** ^Objects of this type are created by [sqlite3_blob_open()]
6786 ** and destroyed by [sqlite3_blob_close()].
6787 ** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
6788 ** can be used to read or write small subsections of the BLOB.
6789 ** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
6790 */
6791 typedef struct sqlite3_blob sqlite3_blob;
6792 
6793 /*
6794 ** CAPI3REF: Open A BLOB For Incremental I/O
6795 ** METHOD: sqlite3
6796 ** CONSTRUCTOR: sqlite3_blob
6797 **
6798 ** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
6799 ** in row iRow, column zColumn, table zTable in database zDb;
6800 ** in other words, the same BLOB that would be selected by:
6801 **
6802 ** <pre>
6803 **     SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
6804 ** </pre>)^
6805 **
6806 ** ^(Parameter zDb is not the filename that contains the database, but
6807 ** rather the symbolic name of the database. For attached databases, this is
6808 ** the name that appears after the AS keyword in the [ATTACH] statement.
6809 ** For the main database file, the database name is "main". For TEMP
6810 ** tables, the database name is "temp".)^
6811 **
6812 ** ^If the flags parameter is non-zero, then the BLOB is opened for read
6813 ** and write access. ^If the flags parameter is zero, the BLOB is opened for
6814 ** read-only access.
6815 **
6816 ** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored
6817 ** in *ppBlob. Otherwise an [error code] is returned and, unless the error
6818 ** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided
6819 ** the API is not misused, it is always safe to call [sqlite3_blob_close()]
6820 ** on *ppBlob after this function it returns.
6821 **
6822 ** This function fails with SQLITE_ERROR if any of the following are true:
6823 ** <ul>
6824 **   <li> ^(Database zDb does not exist)^,
6825 **   <li> ^(Table zTable does not exist within database zDb)^,
6826 **   <li> ^(Table zTable is a WITHOUT ROWID table)^,
6827 **   <li> ^(Column zColumn does not exist)^,
6828 **   <li> ^(Row iRow is not present in the table)^,
6829 **   <li> ^(The specified column of row iRow contains a value that is not
6830 **         a TEXT or BLOB value)^,
6831 **   <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE
6832 **         constraint and the blob is being opened for read/write access)^,
6833 **   <li> ^([foreign key constraints | Foreign key constraints] are enabled,
6834 **         column zColumn is part of a [child key] definition and the blob is
6835 **         being opened for read/write access)^.
6836 ** </ul>
6837 **
6838 ** ^Unless it returns SQLITE_MISUSE, this function sets the
6839 ** [database connection] error code and message accessible via
6840 ** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
6841 **
6842 ** A BLOB referenced by sqlite3_blob_open() may be read using the
6843 ** [sqlite3_blob_read()] interface and modified by using
6844 ** [sqlite3_blob_write()].  The [BLOB handle] can be moved to a
6845 ** different row of the same table using the [sqlite3_blob_reopen()]
6846 ** interface.  However, the column, table, or database of a [BLOB handle]
6847 ** cannot be changed after the [BLOB handle] is opened.
6848 **
6849 ** ^(If the row that a BLOB handle points to is modified by an
6850 ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
6851 ** then the BLOB handle is marked as "expired".
6852 ** This is true if any column of the row is changed, even a column
6853 ** other than the one the BLOB handle is open on.)^
6854 ** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
6855 ** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
6856 ** ^(Changes written into a BLOB prior to the BLOB expiring are not
6857 ** rolled back by the expiration of the BLOB.  Such changes will eventually
6858 ** commit if the transaction continues to completion.)^
6859 **
6860 ** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
6861 ** the opened blob.  ^The size of a blob may not be changed by this
6862 ** interface.  Use the [UPDATE] SQL command to change the size of a
6863 ** blob.
6864 **
6865 ** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
6866 ** and the built-in [zeroblob] SQL function may be used to create a
6867 ** zero-filled blob to read or write using the incremental-blob interface.
6868 **
6869 ** To avoid a resource leak, every open [BLOB handle] should eventually
6870 ** be released by a call to [sqlite3_blob_close()].
6871 **
6872 ** See also: [sqlite3_blob_close()],
6873 ** [sqlite3_blob_reopen()], [sqlite3_blob_read()],
6874 ** [sqlite3_blob_bytes()], [sqlite3_blob_write()].
6875 */
6876 SQLITE_API int sqlite3_blob_open(
6877   sqlite3*,
6878   const char *zDb,
6879   const char *zTable,
6880   const char *zColumn,
6881   sqlite3_int64 iRow,
6882   int flags,
6883   sqlite3_blob **ppBlob
6884 );
6885 
6886 /*
6887 ** CAPI3REF: Move a BLOB Handle to a New Row
6888 ** METHOD: sqlite3_blob
6889 **
6890 ** ^This function is used to move an existing [BLOB handle] so that it points
6891 ** to a different row of the same database table. ^The new row is identified
6892 ** by the rowid value passed as the second argument. Only the row can be
6893 ** changed. ^The database, table and column on which the blob handle is open
6894 ** remain the same. Moving an existing [BLOB handle] to a new row is
6895 ** faster than closing the existing handle and opening a new one.
6896 **
6897 ** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
6898 ** it must exist and there must be either a blob or text value stored in
6899 ** the nominated column.)^ ^If the new row is not present in the table, or if
6900 ** it does not contain a blob or text value, or if another error occurs, an
6901 ** SQLite error code is returned and the blob handle is considered aborted.
6902 ** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
6903 ** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
6904 ** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
6905 ** always returns zero.
6906 **
6907 ** ^This function sets the database handle error code and message.
6908 */
6909 SQLITE_API int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
6910 
6911 /*
6912 ** CAPI3REF: Close A BLOB Handle
6913 ** DESTRUCTOR: sqlite3_blob
6914 **
6915 ** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed
6916 ** unconditionally.  Even if this routine returns an error code, the
6917 ** handle is still closed.)^
6918 **
6919 ** ^If the blob handle being closed was opened for read-write access, and if
6920 ** the database is in auto-commit mode and there are no other open read-write
6921 ** blob handles or active write statements, the current transaction is
6922 ** committed. ^If an error occurs while committing the transaction, an error
6923 ** code is returned and the transaction rolled back.
6924 **
6925 ** Calling this function with an argument that is not a NULL pointer or an
6926 ** open blob handle results in undefined behaviour. ^Calling this routine
6927 ** with a null pointer (such as would be returned by a failed call to
6928 ** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function
6929 ** is passed a valid open blob handle, the values returned by the
6930 ** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning.
6931 */
6932 SQLITE_API int sqlite3_blob_close(sqlite3_blob *);
6933 
6934 /*
6935 ** CAPI3REF: Return The Size Of An Open BLOB
6936 ** METHOD: sqlite3_blob
6937 **
6938 ** ^Returns the size in bytes of the BLOB accessible via the
6939 ** successfully opened [BLOB handle] in its only argument.  ^The
6940 ** incremental blob I/O routines can only read or overwriting existing
6941 ** blob content; they cannot change the size of a blob.
6942 **
6943 ** This routine only works on a [BLOB handle] which has been created
6944 ** by a prior successful call to [sqlite3_blob_open()] and which has not
6945 ** been closed by [sqlite3_blob_close()].  Passing any other pointer in
6946 ** to this routine results in undefined and probably undesirable behavior.
6947 */
6948 SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *);
6949 
6950 /*
6951 ** CAPI3REF: Read Data From A BLOB Incrementally
6952 ** METHOD: sqlite3_blob
6953 **
6954 ** ^(This function is used to read data from an open [BLOB handle] into a
6955 ** caller-supplied buffer. N bytes of data are copied into buffer Z
6956 ** from the open BLOB, starting at offset iOffset.)^
6957 **
6958 ** ^If offset iOffset is less than N bytes from the end of the BLOB,
6959 ** [SQLITE_ERROR] is returned and no data is read.  ^If N or iOffset is
6960 ** less than zero, [SQLITE_ERROR] is returned and no data is read.
6961 ** ^The size of the blob (and hence the maximum value of N+iOffset)
6962 ** can be determined using the [sqlite3_blob_bytes()] interface.
6963 **
6964 ** ^An attempt to read from an expired [BLOB handle] fails with an
6965 ** error code of [SQLITE_ABORT].
6966 **
6967 ** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
6968 ** Otherwise, an [error code] or an [extended error code] is returned.)^
6969 **
6970 ** This routine only works on a [BLOB handle] which has been created
6971 ** by a prior successful call to [sqlite3_blob_open()] and which has not
6972 ** been closed by [sqlite3_blob_close()].  Passing any other pointer in
6973 ** to this routine results in undefined and probably undesirable behavior.
6974 **
6975 ** See also: [sqlite3_blob_write()].
6976 */
6977 SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
6978 
6979 /*
6980 ** CAPI3REF: Write Data Into A BLOB Incrementally
6981 ** METHOD: sqlite3_blob
6982 **
6983 ** ^(This function is used to write data into an open [BLOB handle] from a
6984 ** caller-supplied buffer. N bytes of data are copied from the buffer Z
6985 ** into the open BLOB, starting at offset iOffset.)^
6986 **
6987 ** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
6988 ** Otherwise, an  [error code] or an [extended error code] is returned.)^
6989 ** ^Unless SQLITE_MISUSE is returned, this function sets the
6990 ** [database connection] error code and message accessible via
6991 ** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
6992 **
6993 ** ^If the [BLOB handle] passed as the first argument was not opened for
6994 ** writing (the flags parameter to [sqlite3_blob_open()] was zero),
6995 ** this function returns [SQLITE_READONLY].
6996 **
6997 ** This function may only modify the contents of the BLOB; it is
6998 ** not possible to increase the size of a BLOB using this API.
6999 ** ^If offset iOffset is less than N bytes from the end of the BLOB,
7000 ** [SQLITE_ERROR] is returned and no data is written. The size of the
7001 ** BLOB (and hence the maximum value of N+iOffset) can be determined
7002 ** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less
7003 ** than zero [SQLITE_ERROR] is returned and no data is written.
7004 **
7005 ** ^An attempt to write to an expired [BLOB handle] fails with an
7006 ** error code of [SQLITE_ABORT].  ^Writes to the BLOB that occurred
7007 ** before the [BLOB handle] expired are not rolled back by the
7008 ** expiration of the handle, though of course those changes might
7009 ** have been overwritten by the statement that expired the BLOB handle
7010 ** or by other independent statements.
7011 **
7012 ** This routine only works on a [BLOB handle] which has been created
7013 ** by a prior successful call to [sqlite3_blob_open()] and which has not
7014 ** been closed by [sqlite3_blob_close()].  Passing any other pointer in
7015 ** to this routine results in undefined and probably undesirable behavior.
7016 **
7017 ** See also: [sqlite3_blob_read()].
7018 */
7019 SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
7020 
7021 /*
7022 ** CAPI3REF: Virtual File System Objects
7023 **
7024 ** A virtual filesystem (VFS) is an [sqlite3_vfs] object
7025 ** that SQLite uses to interact
7026 ** with the underlying operating system.  Most SQLite builds come with a
7027 ** single default VFS that is appropriate for the host computer.
7028 ** New VFSes can be registered and existing VFSes can be unregistered.
7029 ** The following interfaces are provided.
7030 **
7031 ** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
7032 ** ^Names are case sensitive.
7033 ** ^Names are zero-terminated UTF-8 strings.
7034 ** ^If there is no match, a NULL pointer is returned.
7035 ** ^If zVfsName is NULL then the default VFS is returned.
7036 **
7037 ** ^New VFSes are registered with sqlite3_vfs_register().
7038 ** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
7039 ** ^The same VFS can be registered multiple times without injury.
7040 ** ^To make an existing VFS into the default VFS, register it again
7041 ** with the makeDflt flag set.  If two different VFSes with the
7042 ** same name are registered, the behavior is undefined.  If a
7043 ** VFS is registered with a name that is NULL or an empty string,
7044 ** then the behavior is undefined.
7045 **
7046 ** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
7047 ** ^(If the default VFS is unregistered, another VFS is chosen as
7048 ** the default.  The choice for the new VFS is arbitrary.)^
7049 */
7050 SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
7051 SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
7052 SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*);
7053 
7054 /*
7055 ** CAPI3REF: Mutexes
7056 **
7057 ** The SQLite core uses these routines for thread
7058 ** synchronization. Though they are intended for internal
7059 ** use by SQLite, code that links against SQLite is
7060 ** permitted to use any of these routines.
7061 **
7062 ** The SQLite source code contains multiple implementations
7063 ** of these mutex routines.  An appropriate implementation
7064 ** is selected automatically at compile-time.  The following
7065 ** implementations are available in the SQLite core:
7066 **
7067 ** <ul>
7068 ** <li>   SQLITE_MUTEX_PTHREADS
7069 ** <li>   SQLITE_MUTEX_W32
7070 ** <li>   SQLITE_MUTEX_NOOP
7071 ** </ul>
7072 **
7073 ** The SQLITE_MUTEX_NOOP implementation is a set of routines
7074 ** that does no real locking and is appropriate for use in
7075 ** a single-threaded application.  The SQLITE_MUTEX_PTHREADS and
7076 ** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
7077 ** and Windows.
7078 **
7079 ** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
7080 ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
7081 ** implementation is included with the library. In this case the
7082 ** application must supply a custom mutex implementation using the
7083 ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
7084 ** before calling sqlite3_initialize() or any other public sqlite3_
7085 ** function that calls sqlite3_initialize().
7086 **
7087 ** ^The sqlite3_mutex_alloc() routine allocates a new
7088 ** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc()
7089 ** routine returns NULL if it is unable to allocate the requested
7090 ** mutex.  The argument to sqlite3_mutex_alloc() must one of these
7091 ** integer constants:
7092 **
7093 ** <ul>
7094 ** <li>  SQLITE_MUTEX_FAST
7095 ** <li>  SQLITE_MUTEX_RECURSIVE
7096 ** <li>  SQLITE_MUTEX_STATIC_MASTER
7097 ** <li>  SQLITE_MUTEX_STATIC_MEM
7098 ** <li>  SQLITE_MUTEX_STATIC_OPEN
7099 ** <li>  SQLITE_MUTEX_STATIC_PRNG
7100 ** <li>  SQLITE_MUTEX_STATIC_LRU
7101 ** <li>  SQLITE_MUTEX_STATIC_PMEM
7102 ** <li>  SQLITE_MUTEX_STATIC_APP1
7103 ** <li>  SQLITE_MUTEX_STATIC_APP2
7104 ** <li>  SQLITE_MUTEX_STATIC_APP3
7105 ** <li>  SQLITE_MUTEX_STATIC_VFS1
7106 ** <li>  SQLITE_MUTEX_STATIC_VFS2
7107 ** <li>  SQLITE_MUTEX_STATIC_VFS3
7108 ** </ul>
7109 **
7110 ** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
7111 ** cause sqlite3_mutex_alloc() to create
7112 ** a new mutex.  ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
7113 ** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
7114 ** The mutex implementation does not need to make a distinction
7115 ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
7116 ** not want to.  SQLite will only request a recursive mutex in
7117 ** cases where it really needs one.  If a faster non-recursive mutex
7118 ** implementation is available on the host platform, the mutex subsystem
7119 ** might return such a mutex in response to SQLITE_MUTEX_FAST.
7120 **
7121 ** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
7122 ** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
7123 ** a pointer to a static preexisting mutex.  ^Nine static mutexes are
7124 ** used by the current version of SQLite.  Future versions of SQLite
7125 ** may add additional static mutexes.  Static mutexes are for internal
7126 ** use by SQLite only.  Applications that use SQLite mutexes should
7127 ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
7128 ** SQLITE_MUTEX_RECURSIVE.
7129 **
7130 ** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
7131 ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
7132 ** returns a different mutex on every call.  ^For the static
7133 ** mutex types, the same mutex is returned on every call that has
7134 ** the same type number.
7135 **
7136 ** ^The sqlite3_mutex_free() routine deallocates a previously
7137 ** allocated dynamic mutex.  Attempting to deallocate a static
7138 ** mutex results in undefined behavior.
7139 **
7140 ** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
7141 ** to enter a mutex.  ^If another thread is already within the mutex,
7142 ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
7143 ** SQLITE_BUSY.  ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
7144 ** upon successful entry.  ^(Mutexes created using
7145 ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
7146 ** In such cases, the
7147 ** mutex must be exited an equal number of times before another thread
7148 ** can enter.)^  If the same thread tries to enter any mutex other
7149 ** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined.
7150 **
7151 ** ^(Some systems (for example, Windows 95) do not support the operation
7152 ** implemented by sqlite3_mutex_try().  On those systems, sqlite3_mutex_try()
7153 ** will always return SQLITE_BUSY. The SQLite core only ever uses
7154 ** sqlite3_mutex_try() as an optimization so this is acceptable
7155 ** behavior.)^
7156 **
7157 ** ^The sqlite3_mutex_leave() routine exits a mutex that was
7158 ** previously entered by the same thread.   The behavior
7159 ** is undefined if the mutex is not currently entered by the
7160 ** calling thread or is not currently allocated.
7161 **
7162 ** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
7163 ** sqlite3_mutex_leave() is a NULL pointer, then all three routines
7164 ** behave as no-ops.
7165 **
7166 ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
7167 */
7168 SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int);
7169 SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*);
7170 SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*);
7171 SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*);
7172 SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*);
7173 
7174 /*
7175 ** CAPI3REF: Mutex Methods Object
7176 **
7177 ** An instance of this structure defines the low-level routines
7178 ** used to allocate and use mutexes.
7179 **
7180 ** Usually, the default mutex implementations provided by SQLite are
7181 ** sufficient, however the application has the option of substituting a custom
7182 ** implementation for specialized deployments or systems for which SQLite
7183 ** does not provide a suitable implementation. In this case, the application
7184 ** creates and populates an instance of this structure to pass
7185 ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
7186 ** Additionally, an instance of this structure can be used as an
7187 ** output variable when querying the system for the current mutex
7188 ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
7189 **
7190 ** ^The xMutexInit method defined by this structure is invoked as
7191 ** part of system initialization by the sqlite3_initialize() function.
7192 ** ^The xMutexInit routine is called by SQLite exactly once for each
7193 ** effective call to [sqlite3_initialize()].
7194 **
7195 ** ^The xMutexEnd method defined by this structure is invoked as
7196 ** part of system shutdown by the sqlite3_shutdown() function. The
7197 ** implementation of this method is expected to release all outstanding
7198 ** resources obtained by the mutex methods implementation, especially
7199 ** those obtained by the xMutexInit method.  ^The xMutexEnd()
7200 ** interface is invoked exactly once for each call to [sqlite3_shutdown()].
7201 **
7202 ** ^(The remaining seven methods defined by this structure (xMutexAlloc,
7203 ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
7204 ** xMutexNotheld) implement the following interfaces (respectively):
7205 **
7206 ** <ul>
7207 **   <li>  [sqlite3_mutex_alloc()] </li>
7208 **   <li>  [sqlite3_mutex_free()] </li>
7209 **   <li>  [sqlite3_mutex_enter()] </li>
7210 **   <li>  [sqlite3_mutex_try()] </li>
7211 **   <li>  [sqlite3_mutex_leave()] </li>
7212 **   <li>  [sqlite3_mutex_held()] </li>
7213 **   <li>  [sqlite3_mutex_notheld()] </li>
7214 ** </ul>)^
7215 **
7216 ** The only difference is that the public sqlite3_XXX functions enumerated
7217 ** above silently ignore any invocations that pass a NULL pointer instead
7218 ** of a valid mutex handle. The implementations of the methods defined
7219 ** by this structure are not required to handle this case, the results
7220 ** of passing a NULL pointer instead of a valid mutex handle are undefined
7221 ** (i.e. it is acceptable to provide an implementation that segfaults if
7222 ** it is passed a NULL pointer).
7223 **
7224 ** The xMutexInit() method must be threadsafe.  It must be harmless to
7225 ** invoke xMutexInit() multiple times within the same process and without
7226 ** intervening calls to xMutexEnd().  Second and subsequent calls to
7227 ** xMutexInit() must be no-ops.
7228 **
7229 ** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
7230 ** and its associates).  Similarly, xMutexAlloc() must not use SQLite memory
7231 ** allocation for a static mutex.  ^However xMutexAlloc() may use SQLite
7232 ** memory allocation for a fast or recursive mutex.
7233 **
7234 ** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
7235 ** called, but only if the prior call to xMutexInit returned SQLITE_OK.
7236 ** If xMutexInit fails in any way, it is expected to clean up after itself
7237 ** prior to returning.
7238 */
7239 typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
7240 struct sqlite3_mutex_methods {
7241   int (*xMutexInit)(void);
7242   int (*xMutexEnd)(void);
7243   sqlite3_mutex *(*xMutexAlloc)(int);
7244   void (*xMutexFree)(sqlite3_mutex *);
7245   void (*xMutexEnter)(sqlite3_mutex *);
7246   int (*xMutexTry)(sqlite3_mutex *);
7247   void (*xMutexLeave)(sqlite3_mutex *);
7248   int (*xMutexHeld)(sqlite3_mutex *);
7249   int (*xMutexNotheld)(sqlite3_mutex *);
7250 };
7251 
7252 /*
7253 ** CAPI3REF: Mutex Verification Routines
7254 **
7255 ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
7256 ** are intended for use inside assert() statements.  The SQLite core
7257 ** never uses these routines except inside an assert() and applications
7258 ** are advised to follow the lead of the core.  The SQLite core only
7259 ** provides implementations for these routines when it is compiled
7260 ** with the SQLITE_DEBUG flag.  External mutex implementations
7261 ** are only required to provide these routines if SQLITE_DEBUG is
7262 ** defined and if NDEBUG is not defined.
7263 **
7264 ** These routines should return true if the mutex in their argument
7265 ** is held or not held, respectively, by the calling thread.
7266 **
7267 ** The implementation is not required to provide versions of these
7268 ** routines that actually work. If the implementation does not provide working
7269 ** versions of these routines, it should at least provide stubs that always
7270 ** return true so that one does not get spurious assertion failures.
7271 **
7272 ** If the argument to sqlite3_mutex_held() is a NULL pointer then
7273 ** the routine should return 1.   This seems counter-intuitive since
7274 ** clearly the mutex cannot be held if it does not exist.  But
7275 ** the reason the mutex does not exist is because the build is not
7276 ** using mutexes.  And we do not want the assert() containing the
7277 ** call to sqlite3_mutex_held() to fail, so a non-zero return is
7278 ** the appropriate thing to do.  The sqlite3_mutex_notheld()
7279 ** interface should also return 1 when given a NULL pointer.
7280 */
7281 #ifndef NDEBUG
7282 SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*);
7283 SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*);
7284 #endif
7285 
7286 /*
7287 ** CAPI3REF: Mutex Types
7288 **
7289 ** The [sqlite3_mutex_alloc()] interface takes a single argument
7290 ** which is one of these integer constants.
7291 **
7292 ** The set of static mutexes may change from one SQLite release to the
7293 ** next.  Applications that override the built-in mutex logic must be
7294 ** prepared to accommodate additional static mutexes.
7295 */
7296 #define SQLITE_MUTEX_FAST             0
7297 #define SQLITE_MUTEX_RECURSIVE        1
7298 #define SQLITE_MUTEX_STATIC_MASTER    2
7299 #define SQLITE_MUTEX_STATIC_MEM       3  /* sqlite3_malloc() */
7300 #define SQLITE_MUTEX_STATIC_MEM2      4  /* NOT USED */
7301 #define SQLITE_MUTEX_STATIC_OPEN      4  /* sqlite3BtreeOpen() */
7302 #define SQLITE_MUTEX_STATIC_PRNG      5  /* sqlite3_randomness() */
7303 #define SQLITE_MUTEX_STATIC_LRU       6  /* lru page list */
7304 #define SQLITE_MUTEX_STATIC_LRU2      7  /* NOT USED */
7305 #define SQLITE_MUTEX_STATIC_PMEM      7  /* sqlite3PageMalloc() */
7306 #define SQLITE_MUTEX_STATIC_APP1      8  /* For use by application */
7307 #define SQLITE_MUTEX_STATIC_APP2      9  /* For use by application */
7308 #define SQLITE_MUTEX_STATIC_APP3     10  /* For use by application */
7309 #define SQLITE_MUTEX_STATIC_VFS1     11  /* For use by built-in VFS */
7310 #define SQLITE_MUTEX_STATIC_VFS2     12  /* For use by extension VFS */
7311 #define SQLITE_MUTEX_STATIC_VFS3     13  /* For use by application VFS */
7312 
7313 /*
7314 ** CAPI3REF: Retrieve the mutex for a database connection
7315 ** METHOD: sqlite3
7316 **
7317 ** ^This interface returns a pointer the [sqlite3_mutex] object that
7318 ** serializes access to the [database connection] given in the argument
7319 ** when the [threading mode] is Serialized.
7320 ** ^If the [threading mode] is Single-thread or Multi-thread then this
7321 ** routine returns a NULL pointer.
7322 */
7323 SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
7324 
7325 /*
7326 ** CAPI3REF: Low-Level Control Of Database Files
7327 ** METHOD: sqlite3
7328 ** KEYWORDS: {file control}
7329 **
7330 ** ^The [sqlite3_file_control()] interface makes a direct call to the
7331 ** xFileControl method for the [sqlite3_io_methods] object associated
7332 ** with a particular database identified by the second argument. ^The
7333 ** name of the database is "main" for the main database or "temp" for the
7334 ** TEMP database, or the name that appears after the AS keyword for
7335 ** databases that are added using the [ATTACH] SQL command.
7336 ** ^A NULL pointer can be used in place of "main" to refer to the
7337 ** main database file.
7338 ** ^The third and fourth parameters to this routine
7339 ** are passed directly through to the second and third parameters of
7340 ** the xFileControl method.  ^The return value of the xFileControl
7341 ** method becomes the return value of this routine.
7342 **
7343 ** A few opcodes for [sqlite3_file_control()] are handled directly
7344 ** by the SQLite core and never invoke the
7345 ** sqlite3_io_methods.xFileControl method.
7346 ** ^The [SQLITE_FCNTL_FILE_POINTER] value for the op parameter causes
7347 ** a pointer to the underlying [sqlite3_file] object to be written into
7348 ** the space pointed to by the 4th parameter.  The
7349 ** [SQLITE_FCNTL_JOURNAL_POINTER] works similarly except that it returns
7350 ** the [sqlite3_file] object associated with the journal file instead of
7351 ** the main database.  The [SQLITE_FCNTL_VFS_POINTER] opcode returns
7352 ** a pointer to the underlying [sqlite3_vfs] object for the file.
7353 ** The [SQLITE_FCNTL_DATA_VERSION] returns the data version counter
7354 ** from the pager.
7355 **
7356 ** ^If the second parameter (zDbName) does not match the name of any
7357 ** open database file, then SQLITE_ERROR is returned.  ^This error
7358 ** code is not remembered and will not be recalled by [sqlite3_errcode()]
7359 ** or [sqlite3_errmsg()].  The underlying xFileControl method might
7360 ** also return SQLITE_ERROR.  There is no way to distinguish between
7361 ** an incorrect zDbName and an SQLITE_ERROR return from the underlying
7362 ** xFileControl method.
7363 **
7364 ** See also: [file control opcodes]
7365 */
7366 SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
7367 
7368 /*
7369 ** CAPI3REF: Testing Interface
7370 **
7371 ** ^The sqlite3_test_control() interface is used to read out internal
7372 ** state of SQLite and to inject faults into SQLite for testing
7373 ** purposes.  ^The first parameter is an operation code that determines
7374 ** the number, meaning, and operation of all subsequent parameters.
7375 **
7376 ** This interface is not for use by applications.  It exists solely
7377 ** for verifying the correct operation of the SQLite library.  Depending
7378 ** on how the SQLite library is compiled, this interface might not exist.
7379 **
7380 ** The details of the operation codes, their meanings, the parameters
7381 ** they take, and what they do are all subject to change without notice.
7382 ** Unlike most of the SQLite API, this function is not guaranteed to
7383 ** operate consistently from one release to the next.
7384 */
7385 SQLITE_API int sqlite3_test_control(int op, ...);
7386 
7387 /*
7388 ** CAPI3REF: Testing Interface Operation Codes
7389 **
7390 ** These constants are the valid operation code parameters used
7391 ** as the first argument to [sqlite3_test_control()].
7392 **
7393 ** These parameters and their meanings are subject to change
7394 ** without notice.  These values are for testing purposes only.
7395 ** Applications should not use any of these parameters or the
7396 ** [sqlite3_test_control()] interface.
7397 */
7398 #define SQLITE_TESTCTRL_FIRST                    5
7399 #define SQLITE_TESTCTRL_PRNG_SAVE                5
7400 #define SQLITE_TESTCTRL_PRNG_RESTORE             6
7401 #define SQLITE_TESTCTRL_PRNG_RESET               7  /* NOT USED */
7402 #define SQLITE_TESTCTRL_BITVEC_TEST              8
7403 #define SQLITE_TESTCTRL_FAULT_INSTALL            9
7404 #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS     10
7405 #define SQLITE_TESTCTRL_PENDING_BYTE            11
7406 #define SQLITE_TESTCTRL_ASSERT                  12
7407 #define SQLITE_TESTCTRL_ALWAYS                  13
7408 #define SQLITE_TESTCTRL_RESERVE                 14
7409 #define SQLITE_TESTCTRL_OPTIMIZATIONS           15
7410 #define SQLITE_TESTCTRL_ISKEYWORD               16  /* NOT USED */
7411 #define SQLITE_TESTCTRL_SCRATCHMALLOC           17  /* NOT USED */
7412 #define SQLITE_TESTCTRL_INTERNAL_FUNCTIONS      17
7413 #define SQLITE_TESTCTRL_LOCALTIME_FAULT         18
7414 #define SQLITE_TESTCTRL_EXPLAIN_STMT            19  /* NOT USED */
7415 #define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD    19
7416 #define SQLITE_TESTCTRL_NEVER_CORRUPT           20
7417 #define SQLITE_TESTCTRL_VDBE_COVERAGE           21
7418 #define SQLITE_TESTCTRL_BYTEORDER               22
7419 #define SQLITE_TESTCTRL_ISINIT                  23
7420 #define SQLITE_TESTCTRL_SORTER_MMAP             24
7421 #define SQLITE_TESTCTRL_IMPOSTER                25
7422 #define SQLITE_TESTCTRL_PARSER_COVERAGE         26
7423 #define SQLITE_TESTCTRL_RESULT_INTREAL          27
7424 #define SQLITE_TESTCTRL_PRNG_SEED               28
7425 #define SQLITE_TESTCTRL_EXTRA_SCHEMA_CHECKS     29
7426 #define SQLITE_TESTCTRL_LAST                    29  /* Largest TESTCTRL */
7427 
7428 /*
7429 ** CAPI3REF: SQL Keyword Checking
7430 **
7431 ** These routines provide access to the set of SQL language keywords
7432 ** recognized by SQLite.  Applications can uses these routines to determine
7433 ** whether or not a specific identifier needs to be escaped (for example,
7434 ** by enclosing in double-quotes) so as not to confuse the parser.
7435 **
7436 ** The sqlite3_keyword_count() interface returns the number of distinct
7437 ** keywords understood by SQLite.
7438 **
7439 ** The sqlite3_keyword_name(N,Z,L) interface finds the N-th keyword and
7440 ** makes *Z point to that keyword expressed as UTF8 and writes the number
7441 ** of bytes in the keyword into *L.  The string that *Z points to is not
7442 ** zero-terminated.  The sqlite3_keyword_name(N,Z,L) routine returns
7443 ** SQLITE_OK if N is within bounds and SQLITE_ERROR if not. If either Z
7444 ** or L are NULL or invalid pointers then calls to
7445 ** sqlite3_keyword_name(N,Z,L) result in undefined behavior.
7446 **
7447 ** The sqlite3_keyword_check(Z,L) interface checks to see whether or not
7448 ** the L-byte UTF8 identifier that Z points to is a keyword, returning non-zero
7449 ** if it is and zero if not.
7450 **
7451 ** The parser used by SQLite is forgiving.  It is often possible to use
7452 ** a keyword as an identifier as long as such use does not result in a
7453 ** parsing ambiguity.  For example, the statement
7454 ** "CREATE TABLE BEGIN(REPLACE,PRAGMA,END);" is accepted by SQLite, and
7455 ** creates a new table named "BEGIN" with three columns named
7456 ** "REPLACE", "PRAGMA", and "END".  Nevertheless, best practice is to avoid
7457 ** using keywords as identifiers.  Common techniques used to avoid keyword
7458 ** name collisions include:
7459 ** <ul>
7460 ** <li> Put all identifier names inside double-quotes.  This is the official
7461 **      SQL way to escape identifier names.
7462 ** <li> Put identifier names inside &#91;...&#93;.  This is not standard SQL,
7463 **      but it is what SQL Server does and so lots of programmers use this
7464 **      technique.
7465 ** <li> Begin every identifier with the letter "Z" as no SQL keywords start
7466 **      with "Z".
7467 ** <li> Include a digit somewhere in every identifier name.
7468 ** </ul>
7469 **
7470 ** Note that the number of keywords understood by SQLite can depend on
7471 ** compile-time options.  For example, "VACUUM" is not a keyword if
7472 ** SQLite is compiled with the [-DSQLITE_OMIT_VACUUM] option.  Also,
7473 ** new keywords may be added to future releases of SQLite.
7474 */
7475 SQLITE_API int sqlite3_keyword_count(void);
7476 SQLITE_API int sqlite3_keyword_name(int,const char**,int*);
7477 SQLITE_API int sqlite3_keyword_check(const char*,int);
7478 
7479 /*
7480 ** CAPI3REF: Dynamic String Object
7481 ** KEYWORDS: {dynamic string}
7482 **
7483 ** An instance of the sqlite3_str object contains a dynamically-sized
7484 ** string under construction.
7485 **
7486 ** The lifecycle of an sqlite3_str object is as follows:
7487 ** <ol>
7488 ** <li> ^The sqlite3_str object is created using [sqlite3_str_new()].
7489 ** <li> ^Text is appended to the sqlite3_str object using various
7490 ** methods, such as [sqlite3_str_appendf()].
7491 ** <li> ^The sqlite3_str object is destroyed and the string it created
7492 ** is returned using the [sqlite3_str_finish()] interface.
7493 ** </ol>
7494 */
7495 typedef struct sqlite3_str sqlite3_str;
7496 
7497 /*
7498 ** CAPI3REF: Create A New Dynamic String Object
7499 ** CONSTRUCTOR: sqlite3_str
7500 **
7501 ** ^The [sqlite3_str_new(D)] interface allocates and initializes
7502 ** a new [sqlite3_str] object.  To avoid memory leaks, the object returned by
7503 ** [sqlite3_str_new()] must be freed by a subsequent call to
7504 ** [sqlite3_str_finish(X)].
7505 **
7506 ** ^The [sqlite3_str_new(D)] interface always returns a pointer to a
7507 ** valid [sqlite3_str] object, though in the event of an out-of-memory
7508 ** error the returned object might be a special singleton that will
7509 ** silently reject new text, always return SQLITE_NOMEM from
7510 ** [sqlite3_str_errcode()], always return 0 for
7511 ** [sqlite3_str_length()], and always return NULL from
7512 ** [sqlite3_str_finish(X)].  It is always safe to use the value
7513 ** returned by [sqlite3_str_new(D)] as the sqlite3_str parameter
7514 ** to any of the other [sqlite3_str] methods.
7515 **
7516 ** The D parameter to [sqlite3_str_new(D)] may be NULL.  If the
7517 ** D parameter in [sqlite3_str_new(D)] is not NULL, then the maximum
7518 ** length of the string contained in the [sqlite3_str] object will be
7519 ** the value set for [sqlite3_limit](D,[SQLITE_LIMIT_LENGTH]) instead
7520 ** of [SQLITE_MAX_LENGTH].
7521 */
7522 SQLITE_API sqlite3_str *sqlite3_str_new(sqlite3*);
7523 
7524 /*
7525 ** CAPI3REF: Finalize A Dynamic String
7526 ** DESTRUCTOR: sqlite3_str
7527 **
7528 ** ^The [sqlite3_str_finish(X)] interface destroys the sqlite3_str object X
7529 ** and returns a pointer to a memory buffer obtained from [sqlite3_malloc64()]
7530 ** that contains the constructed string.  The calling application should
7531 ** pass the returned value to [sqlite3_free()] to avoid a memory leak.
7532 ** ^The [sqlite3_str_finish(X)] interface may return a NULL pointer if any
7533 ** errors were encountered during construction of the string.  ^The
7534 ** [sqlite3_str_finish(X)] interface will also return a NULL pointer if the
7535 ** string in [sqlite3_str] object X is zero bytes long.
7536 */
7537 SQLITE_API char *sqlite3_str_finish(sqlite3_str*);
7538 
7539 /*
7540 ** CAPI3REF: Add Content To A Dynamic String
7541 ** METHOD: sqlite3_str
7542 **
7543 ** These interfaces add content to an sqlite3_str object previously obtained
7544 ** from [sqlite3_str_new()].
7545 **
7546 ** ^The [sqlite3_str_appendf(X,F,...)] and
7547 ** [sqlite3_str_vappendf(X,F,V)] interfaces uses the [built-in printf]
7548 ** functionality of SQLite to append formatted text onto the end of
7549 ** [sqlite3_str] object X.
7550 **
7551 ** ^The [sqlite3_str_append(X,S,N)] method appends exactly N bytes from string S
7552 ** onto the end of the [sqlite3_str] object X.  N must be non-negative.
7553 ** S must contain at least N non-zero bytes of content.  To append a
7554 ** zero-terminated string in its entirety, use the [sqlite3_str_appendall()]
7555 ** method instead.
7556 **
7557 ** ^The [sqlite3_str_appendall(X,S)] method appends the complete content of
7558 ** zero-terminated string S onto the end of [sqlite3_str] object X.
7559 **
7560 ** ^The [sqlite3_str_appendchar(X,N,C)] method appends N copies of the
7561 ** single-byte character C onto the end of [sqlite3_str] object X.
7562 ** ^This method can be used, for example, to add whitespace indentation.
7563 **
7564 ** ^The [sqlite3_str_reset(X)] method resets the string under construction
7565 ** inside [sqlite3_str] object X back to zero bytes in length.
7566 **
7567 ** These methods do not return a result code.  ^If an error occurs, that fact
7568 ** is recorded in the [sqlite3_str] object and can be recovered by a
7569 ** subsequent call to [sqlite3_str_errcode(X)].
7570 */
7571 SQLITE_API void sqlite3_str_appendf(sqlite3_str*, const char *zFormat, ...);
7572 SQLITE_API void sqlite3_str_vappendf(sqlite3_str*, const char *zFormat, va_list);
7573 SQLITE_API void sqlite3_str_append(sqlite3_str*, const char *zIn, int N);
7574 SQLITE_API void sqlite3_str_appendall(sqlite3_str*, const char *zIn);
7575 SQLITE_API void sqlite3_str_appendchar(sqlite3_str*, int N, char C);
7576 SQLITE_API void sqlite3_str_reset(sqlite3_str*);
7577 
7578 /*
7579 ** CAPI3REF: Status Of A Dynamic String
7580 ** METHOD: sqlite3_str
7581 **
7582 ** These interfaces return the current status of an [sqlite3_str] object.
7583 **
7584 ** ^If any prior errors have occurred while constructing the dynamic string
7585 ** in sqlite3_str X, then the [sqlite3_str_errcode(X)] method will return
7586 ** an appropriate error code.  ^The [sqlite3_str_errcode(X)] method returns
7587 ** [SQLITE_NOMEM] following any out-of-memory error, or
7588 ** [SQLITE_TOOBIG] if the size of the dynamic string exceeds
7589 ** [SQLITE_MAX_LENGTH], or [SQLITE_OK] if there have been no errors.
7590 **
7591 ** ^The [sqlite3_str_length(X)] method returns the current length, in bytes,
7592 ** of the dynamic string under construction in [sqlite3_str] object X.
7593 ** ^The length returned by [sqlite3_str_length(X)] does not include the
7594 ** zero-termination byte.
7595 **
7596 ** ^The [sqlite3_str_value(X)] method returns a pointer to the current
7597 ** content of the dynamic string under construction in X.  The value
7598 ** returned by [sqlite3_str_value(X)] is managed by the sqlite3_str object X
7599 ** and might be freed or altered by any subsequent method on the same
7600 ** [sqlite3_str] object.  Applications must not used the pointer returned
7601 ** [sqlite3_str_value(X)] after any subsequent method call on the same
7602 ** object.  ^Applications may change the content of the string returned
7603 ** by [sqlite3_str_value(X)] as long as they do not write into any bytes
7604 ** outside the range of 0 to [sqlite3_str_length(X)] and do not read or
7605 ** write any byte after any subsequent sqlite3_str method call.
7606 */
7607 SQLITE_API int sqlite3_str_errcode(sqlite3_str*);
7608 SQLITE_API int sqlite3_str_length(sqlite3_str*);
7609 SQLITE_API char *sqlite3_str_value(sqlite3_str*);
7610 
7611 /*
7612 ** CAPI3REF: SQLite Runtime Status
7613 **
7614 ** ^These interfaces are used to retrieve runtime status information
7615 ** about the performance of SQLite, and optionally to reset various
7616 ** highwater marks.  ^The first argument is an integer code for
7617 ** the specific parameter to measure.  ^(Recognized integer codes
7618 ** are of the form [status parameters | SQLITE_STATUS_...].)^
7619 ** ^The current value of the parameter is returned into *pCurrent.
7620 ** ^The highest recorded value is returned in *pHighwater.  ^If the
7621 ** resetFlag is true, then the highest record value is reset after
7622 ** *pHighwater is written.  ^(Some parameters do not record the highest
7623 ** value.  For those parameters
7624 ** nothing is written into *pHighwater and the resetFlag is ignored.)^
7625 ** ^(Other parameters record only the highwater mark and not the current
7626 ** value.  For these latter parameters nothing is written into *pCurrent.)^
7627 **
7628 ** ^The sqlite3_status() and sqlite3_status64() routines return
7629 ** SQLITE_OK on success and a non-zero [error code] on failure.
7630 **
7631 ** If either the current value or the highwater mark is too large to
7632 ** be represented by a 32-bit integer, then the values returned by
7633 ** sqlite3_status() are undefined.
7634 **
7635 ** See also: [sqlite3_db_status()]
7636 */
7637 SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
7638 SQLITE_API int sqlite3_status64(
7639   int op,
7640   sqlite3_int64 *pCurrent,
7641   sqlite3_int64 *pHighwater,
7642   int resetFlag
7643 );
7644 
7645 
7646 /*
7647 ** CAPI3REF: Status Parameters
7648 ** KEYWORDS: {status parameters}
7649 **
7650 ** These integer constants designate various run-time status parameters
7651 ** that can be returned by [sqlite3_status()].
7652 **
7653 ** <dl>
7654 ** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
7655 ** <dd>This parameter is the current amount of memory checked out
7656 ** using [sqlite3_malloc()], either directly or indirectly.  The
7657 ** figure includes calls made to [sqlite3_malloc()] by the application
7658 ** and internal memory usage by the SQLite library.  Auxiliary page-cache
7659 ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
7660 ** this parameter.  The amount returned is the sum of the allocation
7661 ** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
7662 **
7663 ** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
7664 ** <dd>This parameter records the largest memory allocation request
7665 ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
7666 ** internal equivalents).  Only the value returned in the
7667 ** *pHighwater parameter to [sqlite3_status()] is of interest.
7668 ** The value written into the *pCurrent parameter is undefined.</dd>)^
7669 **
7670 ** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
7671 ** <dd>This parameter records the number of separate memory allocations
7672 ** currently checked out.</dd>)^
7673 **
7674 ** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
7675 ** <dd>This parameter returns the number of pages used out of the
7676 ** [pagecache memory allocator] that was configured using
7677 ** [SQLITE_CONFIG_PAGECACHE].  The
7678 ** value returned is in pages, not in bytes.</dd>)^
7679 **
7680 ** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]]
7681 ** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
7682 ** <dd>This parameter returns the number of bytes of page cache
7683 ** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
7684 ** buffer and where forced to overflow to [sqlite3_malloc()].  The
7685 ** returned value includes allocations that overflowed because they
7686 ** where too large (they were larger than the "sz" parameter to
7687 ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
7688 ** no space was left in the page cache.</dd>)^
7689 **
7690 ** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
7691 ** <dd>This parameter records the largest memory allocation request
7692 ** handed to [pagecache memory allocator].  Only the value returned in the
7693 ** *pHighwater parameter to [sqlite3_status()] is of interest.
7694 ** The value written into the *pCurrent parameter is undefined.</dd>)^
7695 **
7696 ** [[SQLITE_STATUS_SCRATCH_USED]] <dt>SQLITE_STATUS_SCRATCH_USED</dt>
7697 ** <dd>No longer used.</dd>
7698 **
7699 ** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
7700 ** <dd>No longer used.</dd>
7701 **
7702 ** [[SQLITE_STATUS_SCRATCH_SIZE]] <dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
7703 ** <dd>No longer used.</dd>
7704 **
7705 ** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
7706 ** <dd>The *pHighwater parameter records the deepest parser stack.
7707 ** The *pCurrent value is undefined.  The *pHighwater value is only
7708 ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
7709 ** </dl>
7710 **
7711 ** New status parameters may be added from time to time.
7712 */
7713 #define SQLITE_STATUS_MEMORY_USED          0
7714 #define SQLITE_STATUS_PAGECACHE_USED       1
7715 #define SQLITE_STATUS_PAGECACHE_OVERFLOW   2
7716 #define SQLITE_STATUS_SCRATCH_USED         3  /* NOT USED */
7717 #define SQLITE_STATUS_SCRATCH_OVERFLOW     4  /* NOT USED */
7718 #define SQLITE_STATUS_MALLOC_SIZE          5
7719 #define SQLITE_STATUS_PARSER_STACK         6
7720 #define SQLITE_STATUS_PAGECACHE_SIZE       7
7721 #define SQLITE_STATUS_SCRATCH_SIZE         8  /* NOT USED */
7722 #define SQLITE_STATUS_MALLOC_COUNT         9
7723 
7724 /*
7725 ** CAPI3REF: Database Connection Status
7726 ** METHOD: sqlite3
7727 **
7728 ** ^This interface is used to retrieve runtime status information
7729 ** about a single [database connection].  ^The first argument is the
7730 ** database connection object to be interrogated.  ^The second argument
7731 ** is an integer constant, taken from the set of
7732 ** [SQLITE_DBSTATUS options], that
7733 ** determines the parameter to interrogate.  The set of
7734 ** [SQLITE_DBSTATUS options] is likely
7735 ** to grow in future releases of SQLite.
7736 **
7737 ** ^The current value of the requested parameter is written into *pCur
7738 ** and the highest instantaneous value is written into *pHiwtr.  ^If
7739 ** the resetFlg is true, then the highest instantaneous value is
7740 ** reset back down to the current value.
7741 **
7742 ** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
7743 ** non-zero [error code] on failure.
7744 **
7745 ** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
7746 */
7747 SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
7748 
7749 /*
7750 ** CAPI3REF: Status Parameters for database connections
7751 ** KEYWORDS: {SQLITE_DBSTATUS options}
7752 **
7753 ** These constants are the available integer "verbs" that can be passed as
7754 ** the second argument to the [sqlite3_db_status()] interface.
7755 **
7756 ** New verbs may be added in future releases of SQLite. Existing verbs
7757 ** might be discontinued. Applications should check the return code from
7758 ** [sqlite3_db_status()] to make sure that the call worked.
7759 ** The [sqlite3_db_status()] interface will return a non-zero error code
7760 ** if a discontinued or unsupported verb is invoked.
7761 **
7762 ** <dl>
7763 ** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
7764 ** <dd>This parameter returns the number of lookaside memory slots currently
7765 ** checked out.</dd>)^
7766 **
7767 ** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
7768 ** <dd>This parameter returns the number malloc attempts that were
7769 ** satisfied using lookaside memory. Only the high-water value is meaningful;
7770 ** the current value is always zero.)^
7771 **
7772 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]]
7773 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
7774 ** <dd>This parameter returns the number malloc attempts that might have
7775 ** been satisfied using lookaside memory but failed due to the amount of
7776 ** memory requested being larger than the lookaside slot size.
7777 ** Only the high-water value is meaningful;
7778 ** the current value is always zero.)^
7779 **
7780 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]]
7781 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
7782 ** <dd>This parameter returns the number malloc attempts that might have
7783 ** been satisfied using lookaside memory but failed due to all lookaside
7784 ** memory already being in use.
7785 ** Only the high-water value is meaningful;
7786 ** the current value is always zero.)^
7787 **
7788 ** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
7789 ** <dd>This parameter returns the approximate number of bytes of heap
7790 ** memory used by all pager caches associated with the database connection.)^
7791 ** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
7792 **
7793 ** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]]
7794 ** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt>
7795 ** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a
7796 ** pager cache is shared between two or more connections the bytes of heap
7797 ** memory used by that pager cache is divided evenly between the attached
7798 ** connections.)^  In other words, if none of the pager caches associated
7799 ** with the database connection are shared, this request returns the same
7800 ** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are
7801 ** shared, the value returned by this call will be smaller than that returned
7802 ** by DBSTATUS_CACHE_USED. ^The highwater mark associated with
7803 ** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0.
7804 **
7805 ** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
7806 ** <dd>This parameter returns the approximate number of bytes of heap
7807 ** memory used to store the schema for all databases associated
7808 ** with the connection - main, temp, and any [ATTACH]-ed databases.)^
7809 ** ^The full amount of memory used by the schemas is reported, even if the
7810 ** schema memory is shared with other database connections due to
7811 ** [shared cache mode] being enabled.
7812 ** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
7813 **
7814 ** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
7815 ** <dd>This parameter returns the approximate number of bytes of heap
7816 ** and lookaside memory used by all prepared statements associated with
7817 ** the database connection.)^
7818 ** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
7819 ** </dd>
7820 **
7821 ** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt>
7822 ** <dd>This parameter returns the number of pager cache hits that have
7823 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT
7824 ** is always 0.
7825 ** </dd>
7826 **
7827 ** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt>
7828 ** <dd>This parameter returns the number of pager cache misses that have
7829 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS
7830 ** is always 0.
7831 ** </dd>
7832 **
7833 ** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt>
7834 ** <dd>This parameter returns the number of dirty cache entries that have
7835 ** been written to disk. Specifically, the number of pages written to the
7836 ** wal file in wal mode databases, or the number of pages written to the
7837 ** database file in rollback mode databases. Any pages written as part of
7838 ** transaction rollback or database recovery operations are not included.
7839 ** If an IO or other error occurs while writing a page to disk, the effect
7840 ** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The
7841 ** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0.
7842 ** </dd>
7843 **
7844 ** [[SQLITE_DBSTATUS_CACHE_SPILL]] ^(<dt>SQLITE_DBSTATUS_CACHE_SPILL</dt>
7845 ** <dd>This parameter returns the number of dirty cache entries that have
7846 ** been written to disk in the middle of a transaction due to the page
7847 ** cache overflowing. Transactions are more efficient if they are written
7848 ** to disk all at once. When pages spill mid-transaction, that introduces
7849 ** additional overhead. This parameter can be used help identify
7850 ** inefficiencies that can be resolve by increasing the cache size.
7851 ** </dd>
7852 **
7853 ** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt>
7854 ** <dd>This parameter returns zero for the current value if and only if
7855 ** all foreign key constraints (deferred or immediate) have been
7856 ** resolved.)^  ^The highwater mark is always 0.
7857 ** </dd>
7858 ** </dl>
7859 */
7860 #define SQLITE_DBSTATUS_LOOKASIDE_USED       0
7861 #define SQLITE_DBSTATUS_CACHE_USED           1
7862 #define SQLITE_DBSTATUS_SCHEMA_USED          2
7863 #define SQLITE_DBSTATUS_STMT_USED            3
7864 #define SQLITE_DBSTATUS_LOOKASIDE_HIT        4
7865 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE  5
7866 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL  6
7867 #define SQLITE_DBSTATUS_CACHE_HIT            7
7868 #define SQLITE_DBSTATUS_CACHE_MISS           8
7869 #define SQLITE_DBSTATUS_CACHE_WRITE          9
7870 #define SQLITE_DBSTATUS_DEFERRED_FKS        10
7871 #define SQLITE_DBSTATUS_CACHE_USED_SHARED   11
7872 #define SQLITE_DBSTATUS_CACHE_SPILL         12
7873 #define SQLITE_DBSTATUS_MAX                 12   /* Largest defined DBSTATUS */
7874 
7875 
7876 /*
7877 ** CAPI3REF: Prepared Statement Status
7878 ** METHOD: sqlite3_stmt
7879 **
7880 ** ^(Each prepared statement maintains various
7881 ** [SQLITE_STMTSTATUS counters] that measure the number
7882 ** of times it has performed specific operations.)^  These counters can
7883 ** be used to monitor the performance characteristics of the prepared
7884 ** statements.  For example, if the number of table steps greatly exceeds
7885 ** the number of table searches or result rows, that would tend to indicate
7886 ** that the prepared statement is using a full table scan rather than
7887 ** an index.
7888 **
7889 ** ^(This interface is used to retrieve and reset counter values from
7890 ** a [prepared statement].  The first argument is the prepared statement
7891 ** object to be interrogated.  The second argument
7892 ** is an integer code for a specific [SQLITE_STMTSTATUS counter]
7893 ** to be interrogated.)^
7894 ** ^The current value of the requested counter is returned.
7895 ** ^If the resetFlg is true, then the counter is reset to zero after this
7896 ** interface call returns.
7897 **
7898 ** See also: [sqlite3_status()] and [sqlite3_db_status()].
7899 */
7900 SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
7901 
7902 /*
7903 ** CAPI3REF: Status Parameters for prepared statements
7904 ** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters}
7905 **
7906 ** These preprocessor macros define integer codes that name counter
7907 ** values associated with the [sqlite3_stmt_status()] interface.
7908 ** The meanings of the various counters are as follows:
7909 **
7910 ** <dl>
7911 ** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
7912 ** <dd>^This is the number of times that SQLite has stepped forward in
7913 ** a table as part of a full table scan.  Large numbers for this counter
7914 ** may indicate opportunities for performance improvement through
7915 ** careful use of indices.</dd>
7916 **
7917 ** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt>
7918 ** <dd>^This is the number of sort operations that have occurred.
7919 ** A non-zero value in this counter may indicate an opportunity to
7920 ** improvement performance through careful use of indices.</dd>
7921 **
7922 ** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
7923 ** <dd>^This is the number of rows inserted into transient indices that
7924 ** were created automatically in order to help joins run faster.
7925 ** A non-zero value in this counter may indicate an opportunity to
7926 ** improvement performance by adding permanent indices that do not
7927 ** need to be reinitialized each time the statement is run.</dd>
7928 **
7929 ** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt>
7930 ** <dd>^This is the number of virtual machine operations executed
7931 ** by the prepared statement if that number is less than or equal
7932 ** to 2147483647.  The number of virtual machine operations can be
7933 ** used as a proxy for the total work done by the prepared statement.
7934 ** If the number of virtual machine operations exceeds 2147483647
7935 ** then the value returned by this statement status code is undefined.
7936 **
7937 ** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt>
7938 ** <dd>^This is the number of times that the prepare statement has been
7939 ** automatically regenerated due to schema changes or change to
7940 ** [bound parameters] that might affect the query plan.
7941 **
7942 ** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt>
7943 ** <dd>^This is the number of times that the prepared statement has
7944 ** been run.  A single "run" for the purposes of this counter is one
7945 ** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()].
7946 ** The counter is incremented on the first [sqlite3_step()] call of each
7947 ** cycle.
7948 **
7949 ** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt>
7950 ** <dd>^This is the approximate number of bytes of heap memory
7951 ** used to store the prepared statement.  ^This value is not actually
7952 ** a counter, and so the resetFlg parameter to sqlite3_stmt_status()
7953 ** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED.
7954 ** </dd>
7955 ** </dl>
7956 */
7957 #define SQLITE_STMTSTATUS_FULLSCAN_STEP     1
7958 #define SQLITE_STMTSTATUS_SORT              2
7959 #define SQLITE_STMTSTATUS_AUTOINDEX         3
7960 #define SQLITE_STMTSTATUS_VM_STEP           4
7961 #define SQLITE_STMTSTATUS_REPREPARE         5
7962 #define SQLITE_STMTSTATUS_RUN               6
7963 #define SQLITE_STMTSTATUS_MEMUSED           99
7964 
7965 /*
7966 ** CAPI3REF: Custom Page Cache Object
7967 **
7968 ** The sqlite3_pcache type is opaque.  It is implemented by
7969 ** the pluggable module.  The SQLite core has no knowledge of
7970 ** its size or internal structure and never deals with the
7971 ** sqlite3_pcache object except by holding and passing pointers
7972 ** to the object.
7973 **
7974 ** See [sqlite3_pcache_methods2] for additional information.
7975 */
7976 typedef struct sqlite3_pcache sqlite3_pcache;
7977 
7978 /*
7979 ** CAPI3REF: Custom Page Cache Object
7980 **
7981 ** The sqlite3_pcache_page object represents a single page in the
7982 ** page cache.  The page cache will allocate instances of this
7983 ** object.  Various methods of the page cache use pointers to instances
7984 ** of this object as parameters or as their return value.
7985 **
7986 ** See [sqlite3_pcache_methods2] for additional information.
7987 */
7988 typedef struct sqlite3_pcache_page sqlite3_pcache_page;
7989 struct sqlite3_pcache_page {
7990   void *pBuf;        /* The content of the page */
7991   void *pExtra;      /* Extra information associated with the page */
7992 };
7993 
7994 /*
7995 ** CAPI3REF: Application Defined Page Cache.
7996 ** KEYWORDS: {page cache}
7997 **
7998 ** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can
7999 ** register an alternative page cache implementation by passing in an
8000 ** instance of the sqlite3_pcache_methods2 structure.)^
8001 ** In many applications, most of the heap memory allocated by
8002 ** SQLite is used for the page cache.
8003 ** By implementing a
8004 ** custom page cache using this API, an application can better control
8005 ** the amount of memory consumed by SQLite, the way in which
8006 ** that memory is allocated and released, and the policies used to
8007 ** determine exactly which parts of a database file are cached and for
8008 ** how long.
8009 **
8010 ** The alternative page cache mechanism is an
8011 ** extreme measure that is only needed by the most demanding applications.
8012 ** The built-in page cache is recommended for most uses.
8013 **
8014 ** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an
8015 ** internal buffer by SQLite within the call to [sqlite3_config].  Hence
8016 ** the application may discard the parameter after the call to
8017 ** [sqlite3_config()] returns.)^
8018 **
8019 ** [[the xInit() page cache method]]
8020 ** ^(The xInit() method is called once for each effective
8021 ** call to [sqlite3_initialize()])^
8022 ** (usually only once during the lifetime of the process). ^(The xInit()
8023 ** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^
8024 ** The intent of the xInit() method is to set up global data structures
8025 ** required by the custom page cache implementation.
8026 ** ^(If the xInit() method is NULL, then the
8027 ** built-in default page cache is used instead of the application defined
8028 ** page cache.)^
8029 **
8030 ** [[the xShutdown() page cache method]]
8031 ** ^The xShutdown() method is called by [sqlite3_shutdown()].
8032 ** It can be used to clean up
8033 ** any outstanding resources before process shutdown, if required.
8034 ** ^The xShutdown() method may be NULL.
8035 **
8036 ** ^SQLite automatically serializes calls to the xInit method,
8037 ** so the xInit method need not be threadsafe.  ^The
8038 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
8039 ** not need to be threadsafe either.  All other methods must be threadsafe
8040 ** in multithreaded applications.
8041 **
8042 ** ^SQLite will never invoke xInit() more than once without an intervening
8043 ** call to xShutdown().
8044 **
8045 ** [[the xCreate() page cache methods]]
8046 ** ^SQLite invokes the xCreate() method to construct a new cache instance.
8047 ** SQLite will typically create one cache instance for each open database file,
8048 ** though this is not guaranteed. ^The
8049 ** first parameter, szPage, is the size in bytes of the pages that must
8050 ** be allocated by the cache.  ^szPage will always a power of two.  ^The
8051 ** second parameter szExtra is a number of bytes of extra storage
8052 ** associated with each page cache entry.  ^The szExtra parameter will
8053 ** a number less than 250.  SQLite will use the
8054 ** extra szExtra bytes on each page to store metadata about the underlying
8055 ** database page on disk.  The value passed into szExtra depends
8056 ** on the SQLite version, the target platform, and how SQLite was compiled.
8057 ** ^The third argument to xCreate(), bPurgeable, is true if the cache being
8058 ** created will be used to cache database pages of a file stored on disk, or
8059 ** false if it is used for an in-memory database. The cache implementation
8060 ** does not have to do anything special based with the value of bPurgeable;
8061 ** it is purely advisory.  ^On a cache where bPurgeable is false, SQLite will
8062 ** never invoke xUnpin() except to deliberately delete a page.
8063 ** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
8064 ** false will always have the "discard" flag set to true.
8065 ** ^Hence, a cache created with bPurgeable false will
8066 ** never contain any unpinned pages.
8067 **
8068 ** [[the xCachesize() page cache method]]
8069 ** ^(The xCachesize() method may be called at any time by SQLite to set the
8070 ** suggested maximum cache-size (number of pages stored by) the cache
8071 ** instance passed as the first argument. This is the value configured using
8072 ** the SQLite "[PRAGMA cache_size]" command.)^  As with the bPurgeable
8073 ** parameter, the implementation is not required to do anything with this
8074 ** value; it is advisory only.
8075 **
8076 ** [[the xPagecount() page cache methods]]
8077 ** The xPagecount() method must return the number of pages currently
8078 ** stored in the cache, both pinned and unpinned.
8079 **
8080 ** [[the xFetch() page cache methods]]
8081 ** The xFetch() method locates a page in the cache and returns a pointer to
8082 ** an sqlite3_pcache_page object associated with that page, or a NULL pointer.
8083 ** The pBuf element of the returned sqlite3_pcache_page object will be a
8084 ** pointer to a buffer of szPage bytes used to store the content of a
8085 ** single database page.  The pExtra element of sqlite3_pcache_page will be
8086 ** a pointer to the szExtra bytes of extra storage that SQLite has requested
8087 ** for each entry in the page cache.
8088 **
8089 ** The page to be fetched is determined by the key. ^The minimum key value
8090 ** is 1.  After it has been retrieved using xFetch, the page is considered
8091 ** to be "pinned".
8092 **
8093 ** If the requested page is already in the page cache, then the page cache
8094 ** implementation must return a pointer to the page buffer with its content
8095 ** intact.  If the requested page is not already in the cache, then the
8096 ** cache implementation should use the value of the createFlag
8097 ** parameter to help it determined what action to take:
8098 **
8099 ** <table border=1 width=85% align=center>
8100 ** <tr><th> createFlag <th> Behavior when page is not already in cache
8101 ** <tr><td> 0 <td> Do not allocate a new page.  Return NULL.
8102 ** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
8103 **                 Otherwise return NULL.
8104 ** <tr><td> 2 <td> Make every effort to allocate a new page.  Only return
8105 **                 NULL if allocating a new page is effectively impossible.
8106 ** </table>
8107 **
8108 ** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1.  SQLite
8109 ** will only use a createFlag of 2 after a prior call with a createFlag of 1
8110 ** failed.)^  In between the to xFetch() calls, SQLite may
8111 ** attempt to unpin one or more cache pages by spilling the content of
8112 ** pinned pages to disk and synching the operating system disk cache.
8113 **
8114 ** [[the xUnpin() page cache method]]
8115 ** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
8116 ** as its second argument.  If the third parameter, discard, is non-zero,
8117 ** then the page must be evicted from the cache.
8118 ** ^If the discard parameter is
8119 ** zero, then the page may be discarded or retained at the discretion of
8120 ** page cache implementation. ^The page cache implementation
8121 ** may choose to evict unpinned pages at any time.
8122 **
8123 ** The cache must not perform any reference counting. A single
8124 ** call to xUnpin() unpins the page regardless of the number of prior calls
8125 ** to xFetch().
8126 **
8127 ** [[the xRekey() page cache methods]]
8128 ** The xRekey() method is used to change the key value associated with the
8129 ** page passed as the second argument. If the cache
8130 ** previously contains an entry associated with newKey, it must be
8131 ** discarded. ^Any prior cache entry associated with newKey is guaranteed not
8132 ** to be pinned.
8133 **
8134 ** When SQLite calls the xTruncate() method, the cache must discard all
8135 ** existing cache entries with page numbers (keys) greater than or equal
8136 ** to the value of the iLimit parameter passed to xTruncate(). If any
8137 ** of these pages are pinned, they are implicitly unpinned, meaning that
8138 ** they can be safely discarded.
8139 **
8140 ** [[the xDestroy() page cache method]]
8141 ** ^The xDestroy() method is used to delete a cache allocated by xCreate().
8142 ** All resources associated with the specified cache should be freed. ^After
8143 ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
8144 ** handle invalid, and will not use it with any other sqlite3_pcache_methods2
8145 ** functions.
8146 **
8147 ** [[the xShrink() page cache method]]
8148 ** ^SQLite invokes the xShrink() method when it wants the page cache to
8149 ** free up as much of heap memory as possible.  The page cache implementation
8150 ** is not obligated to free any memory, but well-behaved implementations should
8151 ** do their best.
8152 */
8153 typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
8154 struct sqlite3_pcache_methods2 {
8155   int iVersion;
8156   void *pArg;
8157   int (*xInit)(void*);
8158   void (*xShutdown)(void*);
8159   sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
8160   void (*xCachesize)(sqlite3_pcache*, int nCachesize);
8161   int (*xPagecount)(sqlite3_pcache*);
8162   sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
8163   void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
8164   void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*,
8165       unsigned oldKey, unsigned newKey);
8166   void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
8167   void (*xDestroy)(sqlite3_pcache*);
8168   void (*xShrink)(sqlite3_pcache*);
8169 };
8170 
8171 /*
8172 ** This is the obsolete pcache_methods object that has now been replaced
8173 ** by sqlite3_pcache_methods2.  This object is not used by SQLite.  It is
8174 ** retained in the header file for backwards compatibility only.
8175 */
8176 typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
8177 struct sqlite3_pcache_methods {
8178   void *pArg;
8179   int (*xInit)(void*);
8180   void (*xShutdown)(void*);
8181   sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
8182   void (*xCachesize)(sqlite3_pcache*, int nCachesize);
8183   int (*xPagecount)(sqlite3_pcache*);
8184   void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
8185   void (*xUnpin)(sqlite3_pcache*, void*, int discard);
8186   void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
8187   void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
8188   void (*xDestroy)(sqlite3_pcache*);
8189 };
8190 
8191 
8192 /*
8193 ** CAPI3REF: Online Backup Object
8194 **
8195 ** The sqlite3_backup object records state information about an ongoing
8196 ** online backup operation.  ^The sqlite3_backup object is created by
8197 ** a call to [sqlite3_backup_init()] and is destroyed by a call to
8198 ** [sqlite3_backup_finish()].
8199 **
8200 ** See Also: [Using the SQLite Online Backup API]
8201 */
8202 typedef struct sqlite3_backup sqlite3_backup;
8203 
8204 /*
8205 ** CAPI3REF: Online Backup API.
8206 **
8207 ** The backup API copies the content of one database into another.
8208 ** It is useful either for creating backups of databases or
8209 ** for copying in-memory databases to or from persistent files.
8210 **
8211 ** See Also: [Using the SQLite Online Backup API]
8212 **
8213 ** ^SQLite holds a write transaction open on the destination database file
8214 ** for the duration of the backup operation.
8215 ** ^The source database is read-locked only while it is being read;
8216 ** it is not locked continuously for the entire backup operation.
8217 ** ^Thus, the backup may be performed on a live source database without
8218 ** preventing other database connections from
8219 ** reading or writing to the source database while the backup is underway.
8220 **
8221 ** ^(To perform a backup operation:
8222 **   <ol>
8223 **     <li><b>sqlite3_backup_init()</b> is called once to initialize the
8224 **         backup,
8225 **     <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
8226 **         the data between the two databases, and finally
8227 **     <li><b>sqlite3_backup_finish()</b> is called to release all resources
8228 **         associated with the backup operation.
8229 **   </ol>)^
8230 ** There should be exactly one call to sqlite3_backup_finish() for each
8231 ** successful call to sqlite3_backup_init().
8232 **
8233 ** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
8234 **
8235 ** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
8236 ** [database connection] associated with the destination database
8237 ** and the database name, respectively.
8238 ** ^The database name is "main" for the main database, "temp" for the
8239 ** temporary database, or the name specified after the AS keyword in
8240 ** an [ATTACH] statement for an attached database.
8241 ** ^The S and M arguments passed to
8242 ** sqlite3_backup_init(D,N,S,M) identify the [database connection]
8243 ** and database name of the source database, respectively.
8244 ** ^The source and destination [database connections] (parameters S and D)
8245 ** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
8246 ** an error.
8247 **
8248 ** ^A call to sqlite3_backup_init() will fail, returning NULL, if
8249 ** there is already a read or read-write transaction open on the
8250 ** destination database.
8251 **
8252 ** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
8253 ** returned and an error code and error message are stored in the
8254 ** destination [database connection] D.
8255 ** ^The error code and message for the failed call to sqlite3_backup_init()
8256 ** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
8257 ** [sqlite3_errmsg16()] functions.
8258 ** ^A successful call to sqlite3_backup_init() returns a pointer to an
8259 ** [sqlite3_backup] object.
8260 ** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
8261 ** sqlite3_backup_finish() functions to perform the specified backup
8262 ** operation.
8263 **
8264 ** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
8265 **
8266 ** ^Function sqlite3_backup_step(B,N) will copy up to N pages between
8267 ** the source and destination databases specified by [sqlite3_backup] object B.
8268 ** ^If N is negative, all remaining source pages are copied.
8269 ** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
8270 ** are still more pages to be copied, then the function returns [SQLITE_OK].
8271 ** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
8272 ** from source to destination, then it returns [SQLITE_DONE].
8273 ** ^If an error occurs while running sqlite3_backup_step(B,N),
8274 ** then an [error code] is returned. ^As well as [SQLITE_OK] and
8275 ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
8276 ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
8277 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
8278 **
8279 ** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
8280 ** <ol>
8281 ** <li> the destination database was opened read-only, or
8282 ** <li> the destination database is using write-ahead-log journaling
8283 ** and the destination and source page sizes differ, or
8284 ** <li> the destination database is an in-memory database and the
8285 ** destination and source page sizes differ.
8286 ** </ol>)^
8287 **
8288 ** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
8289 ** the [sqlite3_busy_handler | busy-handler function]
8290 ** is invoked (if one is specified). ^If the
8291 ** busy-handler returns non-zero before the lock is available, then
8292 ** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
8293 ** sqlite3_backup_step() can be retried later. ^If the source
8294 ** [database connection]
8295 ** is being used to write to the source database when sqlite3_backup_step()
8296 ** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
8297 ** case the call to sqlite3_backup_step() can be retried later on. ^(If
8298 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
8299 ** [SQLITE_READONLY] is returned, then
8300 ** there is no point in retrying the call to sqlite3_backup_step(). These
8301 ** errors are considered fatal.)^  The application must accept
8302 ** that the backup operation has failed and pass the backup operation handle
8303 ** to the sqlite3_backup_finish() to release associated resources.
8304 **
8305 ** ^The first call to sqlite3_backup_step() obtains an exclusive lock
8306 ** on the destination file. ^The exclusive lock is not released until either
8307 ** sqlite3_backup_finish() is called or the backup operation is complete
8308 ** and sqlite3_backup_step() returns [SQLITE_DONE].  ^Every call to
8309 ** sqlite3_backup_step() obtains a [shared lock] on the source database that
8310 ** lasts for the duration of the sqlite3_backup_step() call.
8311 ** ^Because the source database is not locked between calls to
8312 ** sqlite3_backup_step(), the source database may be modified mid-way
8313 ** through the backup process.  ^If the source database is modified by an
8314 ** external process or via a database connection other than the one being
8315 ** used by the backup operation, then the backup will be automatically
8316 ** restarted by the next call to sqlite3_backup_step(). ^If the source
8317 ** database is modified by the using the same database connection as is used
8318 ** by the backup operation, then the backup database is automatically
8319 ** updated at the same time.
8320 **
8321 ** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
8322 **
8323 ** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the
8324 ** application wishes to abandon the backup operation, the application
8325 ** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
8326 ** ^The sqlite3_backup_finish() interfaces releases all
8327 ** resources associated with the [sqlite3_backup] object.
8328 ** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
8329 ** active write-transaction on the destination database is rolled back.
8330 ** The [sqlite3_backup] object is invalid
8331 ** and may not be used following a call to sqlite3_backup_finish().
8332 **
8333 ** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
8334 ** sqlite3_backup_step() errors occurred, regardless or whether or not
8335 ** sqlite3_backup_step() completed.
8336 ** ^If an out-of-memory condition or IO error occurred during any prior
8337 ** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
8338 ** sqlite3_backup_finish() returns the corresponding [error code].
8339 **
8340 ** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
8341 ** is not a permanent error and does not affect the return value of
8342 ** sqlite3_backup_finish().
8343 **
8344 ** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]]
8345 ** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
8346 **
8347 ** ^The sqlite3_backup_remaining() routine returns the number of pages still
8348 ** to be backed up at the conclusion of the most recent sqlite3_backup_step().
8349 ** ^The sqlite3_backup_pagecount() routine returns the total number of pages
8350 ** in the source database at the conclusion of the most recent
8351 ** sqlite3_backup_step().
8352 ** ^(The values returned by these functions are only updated by
8353 ** sqlite3_backup_step(). If the source database is modified in a way that
8354 ** changes the size of the source database or the number of pages remaining,
8355 ** those changes are not reflected in the output of sqlite3_backup_pagecount()
8356 ** and sqlite3_backup_remaining() until after the next
8357 ** sqlite3_backup_step().)^
8358 **
8359 ** <b>Concurrent Usage of Database Handles</b>
8360 **
8361 ** ^The source [database connection] may be used by the application for other
8362 ** purposes while a backup operation is underway or being initialized.
8363 ** ^If SQLite is compiled and configured to support threadsafe database
8364 ** connections, then the source database connection may be used concurrently
8365 ** from within other threads.
8366 **
8367 ** However, the application must guarantee that the destination
8368 ** [database connection] is not passed to any other API (by any thread) after
8369 ** sqlite3_backup_init() is called and before the corresponding call to
8370 ** sqlite3_backup_finish().  SQLite does not currently check to see
8371 ** if the application incorrectly accesses the destination [database connection]
8372 ** and so no error code is reported, but the operations may malfunction
8373 ** nevertheless.  Use of the destination database connection while a
8374 ** backup is in progress might also also cause a mutex deadlock.
8375 **
8376 ** If running in [shared cache mode], the application must
8377 ** guarantee that the shared cache used by the destination database
8378 ** is not accessed while the backup is running. In practice this means
8379 ** that the application must guarantee that the disk file being
8380 ** backed up to is not accessed by any connection within the process,
8381 ** not just the specific connection that was passed to sqlite3_backup_init().
8382 **
8383 ** The [sqlite3_backup] object itself is partially threadsafe. Multiple
8384 ** threads may safely make multiple concurrent calls to sqlite3_backup_step().
8385 ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
8386 ** APIs are not strictly speaking threadsafe. If they are invoked at the
8387 ** same time as another thread is invoking sqlite3_backup_step() it is
8388 ** possible that they return invalid values.
8389 */
8390 SQLITE_API sqlite3_backup *sqlite3_backup_init(
8391   sqlite3 *pDest,                        /* Destination database handle */
8392   const char *zDestName,                 /* Destination database name */
8393   sqlite3 *pSource,                      /* Source database handle */
8394   const char *zSourceName                /* Source database name */
8395 );
8396 SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage);
8397 SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p);
8398 SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p);
8399 SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p);
8400 
8401 /*
8402 ** CAPI3REF: Unlock Notification
8403 ** METHOD: sqlite3
8404 **
8405 ** ^When running in shared-cache mode, a database operation may fail with
8406 ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
8407 ** individual tables within the shared-cache cannot be obtained. See
8408 ** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
8409 ** ^This API may be used to register a callback that SQLite will invoke
8410 ** when the connection currently holding the required lock relinquishes it.
8411 ** ^This API is only available if the library was compiled with the
8412 ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
8413 **
8414 ** See Also: [Using the SQLite Unlock Notification Feature].
8415 **
8416 ** ^Shared-cache locks are released when a database connection concludes
8417 ** its current transaction, either by committing it or rolling it back.
8418 **
8419 ** ^When a connection (known as the blocked connection) fails to obtain a
8420 ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
8421 ** identity of the database connection (the blocking connection) that
8422 ** has locked the required resource is stored internally. ^After an
8423 ** application receives an SQLITE_LOCKED error, it may call the
8424 ** sqlite3_unlock_notify() method with the blocked connection handle as
8425 ** the first argument to register for a callback that will be invoked
8426 ** when the blocking connections current transaction is concluded. ^The
8427 ** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
8428 ** call that concludes the blocking connections transaction.
8429 **
8430 ** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
8431 ** there is a chance that the blocking connection will have already
8432 ** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
8433 ** If this happens, then the specified callback is invoked immediately,
8434 ** from within the call to sqlite3_unlock_notify().)^
8435 **
8436 ** ^If the blocked connection is attempting to obtain a write-lock on a
8437 ** shared-cache table, and more than one other connection currently holds
8438 ** a read-lock on the same table, then SQLite arbitrarily selects one of
8439 ** the other connections to use as the blocking connection.
8440 **
8441 ** ^(There may be at most one unlock-notify callback registered by a
8442 ** blocked connection. If sqlite3_unlock_notify() is called when the
8443 ** blocked connection already has a registered unlock-notify callback,
8444 ** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
8445 ** called with a NULL pointer as its second argument, then any existing
8446 ** unlock-notify callback is canceled. ^The blocked connections
8447 ** unlock-notify callback may also be canceled by closing the blocked
8448 ** connection using [sqlite3_close()].
8449 **
8450 ** The unlock-notify callback is not reentrant. If an application invokes
8451 ** any sqlite3_xxx API functions from within an unlock-notify callback, a
8452 ** crash or deadlock may be the result.
8453 **
8454 ** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
8455 ** returns SQLITE_OK.
8456 **
8457 ** <b>Callback Invocation Details</b>
8458 **
8459 ** When an unlock-notify callback is registered, the application provides a
8460 ** single void* pointer that is passed to the callback when it is invoked.
8461 ** However, the signature of the callback function allows SQLite to pass
8462 ** it an array of void* context pointers. The first argument passed to
8463 ** an unlock-notify callback is a pointer to an array of void* pointers,
8464 ** and the second is the number of entries in the array.
8465 **
8466 ** When a blocking connections transaction is concluded, there may be
8467 ** more than one blocked connection that has registered for an unlock-notify
8468 ** callback. ^If two or more such blocked connections have specified the
8469 ** same callback function, then instead of invoking the callback function
8470 ** multiple times, it is invoked once with the set of void* context pointers
8471 ** specified by the blocked connections bundled together into an array.
8472 ** This gives the application an opportunity to prioritize any actions
8473 ** related to the set of unblocked database connections.
8474 **
8475 ** <b>Deadlock Detection</b>
8476 **
8477 ** Assuming that after registering for an unlock-notify callback a
8478 ** database waits for the callback to be issued before taking any further
8479 ** action (a reasonable assumption), then using this API may cause the
8480 ** application to deadlock. For example, if connection X is waiting for
8481 ** connection Y's transaction to be concluded, and similarly connection
8482 ** Y is waiting on connection X's transaction, then neither connection
8483 ** will proceed and the system may remain deadlocked indefinitely.
8484 **
8485 ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
8486 ** detection. ^If a given call to sqlite3_unlock_notify() would put the
8487 ** system in a deadlocked state, then SQLITE_LOCKED is returned and no
8488 ** unlock-notify callback is registered. The system is said to be in
8489 ** a deadlocked state if connection A has registered for an unlock-notify
8490 ** callback on the conclusion of connection B's transaction, and connection
8491 ** B has itself registered for an unlock-notify callback when connection
8492 ** A's transaction is concluded. ^Indirect deadlock is also detected, so
8493 ** the system is also considered to be deadlocked if connection B has
8494 ** registered for an unlock-notify callback on the conclusion of connection
8495 ** C's transaction, where connection C is waiting on connection A. ^Any
8496 ** number of levels of indirection are allowed.
8497 **
8498 ** <b>The "DROP TABLE" Exception</b>
8499 **
8500 ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost
8501 ** always appropriate to call sqlite3_unlock_notify(). There is however,
8502 ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
8503 ** SQLite checks if there are any currently executing SELECT statements
8504 ** that belong to the same connection. If there are, SQLITE_LOCKED is
8505 ** returned. In this case there is no "blocking connection", so invoking
8506 ** sqlite3_unlock_notify() results in the unlock-notify callback being
8507 ** invoked immediately. If the application then re-attempts the "DROP TABLE"
8508 ** or "DROP INDEX" query, an infinite loop might be the result.
8509 **
8510 ** One way around this problem is to check the extended error code returned
8511 ** by an sqlite3_step() call. ^(If there is a blocking connection, then the
8512 ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
8513 ** the special "DROP TABLE/INDEX" case, the extended error code is just
8514 ** SQLITE_LOCKED.)^
8515 */
8516 SQLITE_API int sqlite3_unlock_notify(
8517   sqlite3 *pBlocked,                          /* Waiting connection */
8518   void (*xNotify)(void **apArg, int nArg),    /* Callback function to invoke */
8519   void *pNotifyArg                            /* Argument to pass to xNotify */
8520 );
8521 
8522 
8523 /*
8524 ** CAPI3REF: String Comparison
8525 **
8526 ** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications
8527 ** and extensions to compare the contents of two buffers containing UTF-8
8528 ** strings in a case-independent fashion, using the same definition of "case
8529 ** independence" that SQLite uses internally when comparing identifiers.
8530 */
8531 SQLITE_API int sqlite3_stricmp(const char *, const char *);
8532 SQLITE_API int sqlite3_strnicmp(const char *, const char *, int);
8533 
8534 /*
8535 ** CAPI3REF: String Globbing
8536 *
8537 ** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if
8538 ** string X matches the [GLOB] pattern P.
8539 ** ^The definition of [GLOB] pattern matching used in
8540 ** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the
8541 ** SQL dialect understood by SQLite.  ^The [sqlite3_strglob(P,X)] function
8542 ** is case sensitive.
8543 **
8544 ** Note that this routine returns zero on a match and non-zero if the strings
8545 ** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
8546 **
8547 ** See also: [sqlite3_strlike()].
8548 */
8549 SQLITE_API int sqlite3_strglob(const char *zGlob, const char *zStr);
8550 
8551 /*
8552 ** CAPI3REF: String LIKE Matching
8553 *
8554 ** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if
8555 ** string X matches the [LIKE] pattern P with escape character E.
8556 ** ^The definition of [LIKE] pattern matching used in
8557 ** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E"
8558 ** operator in the SQL dialect understood by SQLite.  ^For "X LIKE P" without
8559 ** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0.
8560 ** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case
8561 ** insensitive - equivalent upper and lower case ASCII characters match
8562 ** one another.
8563 **
8564 ** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though
8565 ** only ASCII characters are case folded.
8566 **
8567 ** Note that this routine returns zero on a match and non-zero if the strings
8568 ** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
8569 **
8570 ** See also: [sqlite3_strglob()].
8571 */
8572 SQLITE_API int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc);
8573 
8574 /*
8575 ** CAPI3REF: Error Logging Interface
8576 **
8577 ** ^The [sqlite3_log()] interface writes a message into the [error log]
8578 ** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
8579 ** ^If logging is enabled, the zFormat string and subsequent arguments are
8580 ** used with [sqlite3_snprintf()] to generate the final output string.
8581 **
8582 ** The sqlite3_log() interface is intended for use by extensions such as
8583 ** virtual tables, collating functions, and SQL functions.  While there is
8584 ** nothing to prevent an application from calling sqlite3_log(), doing so
8585 ** is considered bad form.
8586 **
8587 ** The zFormat string must not be NULL.
8588 **
8589 ** To avoid deadlocks and other threading problems, the sqlite3_log() routine
8590 ** will not use dynamically allocated memory.  The log message is stored in
8591 ** a fixed-length buffer on the stack.  If the log message is longer than
8592 ** a few hundred characters, it will be truncated to the length of the
8593 ** buffer.
8594 */
8595 SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...);
8596 
8597 /*
8598 ** CAPI3REF: Write-Ahead Log Commit Hook
8599 ** METHOD: sqlite3
8600 **
8601 ** ^The [sqlite3_wal_hook()] function is used to register a callback that
8602 ** is invoked each time data is committed to a database in wal mode.
8603 **
8604 ** ^(The callback is invoked by SQLite after the commit has taken place and
8605 ** the associated write-lock on the database released)^, so the implementation
8606 ** may read, write or [checkpoint] the database as required.
8607 **
8608 ** ^The first parameter passed to the callback function when it is invoked
8609 ** is a copy of the third parameter passed to sqlite3_wal_hook() when
8610 ** registering the callback. ^The second is a copy of the database handle.
8611 ** ^The third parameter is the name of the database that was written to -
8612 ** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
8613 ** is the number of pages currently in the write-ahead log file,
8614 ** including those that were just committed.
8615 **
8616 ** The callback function should normally return [SQLITE_OK].  ^If an error
8617 ** code is returned, that error will propagate back up through the
8618 ** SQLite code base to cause the statement that provoked the callback
8619 ** to report an error, though the commit will have still occurred. If the
8620 ** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
8621 ** that does not correspond to any valid SQLite error code, the results
8622 ** are undefined.
8623 **
8624 ** A single database handle may have at most a single write-ahead log callback
8625 ** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
8626 ** previously registered write-ahead log callback. ^Note that the
8627 ** [sqlite3_wal_autocheckpoint()] interface and the
8628 ** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
8629 ** overwrite any prior [sqlite3_wal_hook()] settings.
8630 */
8631 SQLITE_API void *sqlite3_wal_hook(
8632   sqlite3*,
8633   int(*)(void *,sqlite3*,const char*,int),
8634   void*
8635 );
8636 
8637 /*
8638 ** CAPI3REF: Configure an auto-checkpoint
8639 ** METHOD: sqlite3
8640 **
8641 ** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
8642 ** [sqlite3_wal_hook()] that causes any database on [database connection] D
8643 ** to automatically [checkpoint]
8644 ** after committing a transaction if there are N or
8645 ** more frames in the [write-ahead log] file.  ^Passing zero or
8646 ** a negative value as the nFrame parameter disables automatic
8647 ** checkpoints entirely.
8648 **
8649 ** ^The callback registered by this function replaces any existing callback
8650 ** registered using [sqlite3_wal_hook()].  ^Likewise, registering a callback
8651 ** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
8652 ** configured by this function.
8653 **
8654 ** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
8655 ** from SQL.
8656 **
8657 ** ^Checkpoints initiated by this mechanism are
8658 ** [sqlite3_wal_checkpoint_v2|PASSIVE].
8659 **
8660 ** ^Every new [database connection] defaults to having the auto-checkpoint
8661 ** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
8662 ** pages.  The use of this interface
8663 ** is only necessary if the default setting is found to be suboptimal
8664 ** for a particular application.
8665 */
8666 SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
8667 
8668 /*
8669 ** CAPI3REF: Checkpoint a database
8670 ** METHOD: sqlite3
8671 **
8672 ** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to
8673 ** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^
8674 **
8675 ** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the
8676 ** [write-ahead log] for database X on [database connection] D to be
8677 ** transferred into the database file and for the write-ahead log to
8678 ** be reset.  See the [checkpointing] documentation for addition
8679 ** information.
8680 **
8681 ** This interface used to be the only way to cause a checkpoint to
8682 ** occur.  But then the newer and more powerful [sqlite3_wal_checkpoint_v2()]
8683 ** interface was added.  This interface is retained for backwards
8684 ** compatibility and as a convenience for applications that need to manually
8685 ** start a callback but which do not need the full power (and corresponding
8686 ** complication) of [sqlite3_wal_checkpoint_v2()].
8687 */
8688 SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
8689 
8690 /*
8691 ** CAPI3REF: Checkpoint a database
8692 ** METHOD: sqlite3
8693 **
8694 ** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint
8695 ** operation on database X of [database connection] D in mode M.  Status
8696 ** information is written back into integers pointed to by L and C.)^
8697 ** ^(The M parameter must be a valid [checkpoint mode]:)^
8698 **
8699 ** <dl>
8700 ** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
8701 **   ^Checkpoint as many frames as possible without waiting for any database
8702 **   readers or writers to finish, then sync the database file if all frames
8703 **   in the log were checkpointed. ^The [busy-handler callback]
8704 **   is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode.
8705 **   ^On the other hand, passive mode might leave the checkpoint unfinished
8706 **   if there are concurrent readers or writers.
8707 **
8708 ** <dt>SQLITE_CHECKPOINT_FULL<dd>
8709 **   ^This mode blocks (it invokes the
8710 **   [sqlite3_busy_handler|busy-handler callback]) until there is no
8711 **   database writer and all readers are reading from the most recent database
8712 **   snapshot. ^It then checkpoints all frames in the log file and syncs the
8713 **   database file. ^This mode blocks new database writers while it is pending,
8714 **   but new database readers are allowed to continue unimpeded.
8715 **
8716 ** <dt>SQLITE_CHECKPOINT_RESTART<dd>
8717 **   ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition
8718 **   that after checkpointing the log file it blocks (calls the
8719 **   [busy-handler callback])
8720 **   until all readers are reading from the database file only. ^This ensures
8721 **   that the next writer will restart the log file from the beginning.
8722 **   ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new
8723 **   database writer attempts while it is pending, but does not impede readers.
8724 **
8725 ** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd>
8726 **   ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the
8727 **   addition that it also truncates the log file to zero bytes just prior
8728 **   to a successful return.
8729 ** </dl>
8730 **
8731 ** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in
8732 ** the log file or to -1 if the checkpoint could not run because
8733 ** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not
8734 ** NULL,then *pnCkpt is set to the total number of checkpointed frames in the
8735 ** log file (including any that were already checkpointed before the function
8736 ** was called) or to -1 if the checkpoint could not run due to an error or
8737 ** because the database is not in WAL mode. ^Note that upon successful
8738 ** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been
8739 ** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero.
8740 **
8741 ** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If
8742 ** any other process is running a checkpoint operation at the same time, the
8743 ** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a
8744 ** busy-handler configured, it will not be invoked in this case.
8745 **
8746 ** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the
8747 ** exclusive "writer" lock on the database file. ^If the writer lock cannot be
8748 ** obtained immediately, and a busy-handler is configured, it is invoked and
8749 ** the writer lock retried until either the busy-handler returns 0 or the lock
8750 ** is successfully obtained. ^The busy-handler is also invoked while waiting for
8751 ** database readers as described above. ^If the busy-handler returns 0 before
8752 ** the writer lock is obtained or while waiting for database readers, the
8753 ** checkpoint operation proceeds from that point in the same way as
8754 ** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible
8755 ** without blocking any further. ^SQLITE_BUSY is returned in this case.
8756 **
8757 ** ^If parameter zDb is NULL or points to a zero length string, then the
8758 ** specified operation is attempted on all WAL databases [attached] to
8759 ** [database connection] db.  In this case the
8760 ** values written to output parameters *pnLog and *pnCkpt are undefined. ^If
8761 ** an SQLITE_BUSY error is encountered when processing one or more of the
8762 ** attached WAL databases, the operation is still attempted on any remaining
8763 ** attached databases and SQLITE_BUSY is returned at the end. ^If any other
8764 ** error occurs while processing an attached database, processing is abandoned
8765 ** and the error code is returned to the caller immediately. ^If no error
8766 ** (SQLITE_BUSY or otherwise) is encountered while processing the attached
8767 ** databases, SQLITE_OK is returned.
8768 **
8769 ** ^If database zDb is the name of an attached database that is not in WAL
8770 ** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If
8771 ** zDb is not NULL (or a zero length string) and is not the name of any
8772 ** attached database, SQLITE_ERROR is returned to the caller.
8773 **
8774 ** ^Unless it returns SQLITE_MISUSE,
8775 ** the sqlite3_wal_checkpoint_v2() interface
8776 ** sets the error information that is queried by
8777 ** [sqlite3_errcode()] and [sqlite3_errmsg()].
8778 **
8779 ** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface
8780 ** from SQL.
8781 */
8782 SQLITE_API int sqlite3_wal_checkpoint_v2(
8783   sqlite3 *db,                    /* Database handle */
8784   const char *zDb,                /* Name of attached database (or NULL) */
8785   int eMode,                      /* SQLITE_CHECKPOINT_* value */
8786   int *pnLog,                     /* OUT: Size of WAL log in frames */
8787   int *pnCkpt                     /* OUT: Total number of frames checkpointed */
8788 );
8789 
8790 /*
8791 ** CAPI3REF: Checkpoint Mode Values
8792 ** KEYWORDS: {checkpoint mode}
8793 **
8794 ** These constants define all valid values for the "checkpoint mode" passed
8795 ** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface.
8796 ** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the
8797 ** meaning of each of these checkpoint modes.
8798 */
8799 #define SQLITE_CHECKPOINT_PASSIVE  0  /* Do as much as possible w/o blocking */
8800 #define SQLITE_CHECKPOINT_FULL     1  /* Wait for writers, then checkpoint */
8801 #define SQLITE_CHECKPOINT_RESTART  2  /* Like FULL but wait for for readers */
8802 #define SQLITE_CHECKPOINT_TRUNCATE 3  /* Like RESTART but also truncate WAL */
8803 
8804 /*
8805 ** CAPI3REF: Virtual Table Interface Configuration
8806 **
8807 ** This function may be called by either the [xConnect] or [xCreate] method
8808 ** of a [virtual table] implementation to configure
8809 ** various facets of the virtual table interface.
8810 **
8811 ** If this interface is invoked outside the context of an xConnect or
8812 ** xCreate virtual table method then the behavior is undefined.
8813 **
8814 ** At present, there is only one option that may be configured using
8815 ** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].)  Further options
8816 ** may be added in the future.
8817 */
8818 SQLITE_API int sqlite3_vtab_config(sqlite3*, int op, ...);
8819 
8820 /*
8821 ** CAPI3REF: Virtual Table Configuration Options
8822 **
8823 ** These macros define the various options to the
8824 ** [sqlite3_vtab_config()] interface that [virtual table] implementations
8825 ** can use to customize and optimize their behavior.
8826 **
8827 ** <dl>
8828 ** [[SQLITE_VTAB_CONSTRAINT_SUPPORT]]
8829 ** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT
8830 ** <dd>Calls of the form
8831 ** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
8832 ** where X is an integer.  If X is zero, then the [virtual table] whose
8833 ** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not
8834 ** support constraints.  In this configuration (which is the default) if
8835 ** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire
8836 ** statement is rolled back as if [ON CONFLICT | OR ABORT] had been
8837 ** specified as part of the users SQL statement, regardless of the actual
8838 ** ON CONFLICT mode specified.
8839 **
8840 ** If X is non-zero, then the virtual table implementation guarantees
8841 ** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before
8842 ** any modifications to internal or persistent data structures have been made.
8843 ** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite
8844 ** is able to roll back a statement or database transaction, and abandon
8845 ** or continue processing the current SQL statement as appropriate.
8846 ** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns
8847 ** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode
8848 ** had been ABORT.
8849 **
8850 ** Virtual table implementations that are required to handle OR REPLACE
8851 ** must do so within the [xUpdate] method. If a call to the
8852 ** [sqlite3_vtab_on_conflict()] function indicates that the current ON
8853 ** CONFLICT policy is REPLACE, the virtual table implementation should
8854 ** silently replace the appropriate rows within the xUpdate callback and
8855 ** return SQLITE_OK. Or, if this is not possible, it may return
8856 ** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT
8857 ** constraint handling.
8858 ** </dl>
8859 */
8860 #define SQLITE_VTAB_CONSTRAINT_SUPPORT 1
8861 
8862 /*
8863 ** CAPI3REF: Determine The Virtual Table Conflict Policy
8864 **
8865 ** This function may only be called from within a call to the [xUpdate] method
8866 ** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The
8867 ** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
8868 ** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
8869 ** of the SQL statement that triggered the call to the [xUpdate] method of the
8870 ** [virtual table].
8871 */
8872 SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *);
8873 
8874 /*
8875 ** CAPI3REF: Determine If Virtual Table Column Access Is For UPDATE
8876 **
8877 ** If the sqlite3_vtab_nochange(X) routine is called within the [xColumn]
8878 ** method of a [virtual table], then it returns true if and only if the
8879 ** column is being fetched as part of an UPDATE operation during which the
8880 ** column value will not change.  Applications might use this to substitute
8881 ** a return value that is less expensive to compute and that the corresponding
8882 ** [xUpdate] method understands as a "no-change" value.
8883 **
8884 ** If the [xColumn] method calls sqlite3_vtab_nochange() and finds that
8885 ** the column is not changed by the UPDATE statement, then the xColumn
8886 ** method can optionally return without setting a result, without calling
8887 ** any of the [sqlite3_result_int|sqlite3_result_xxxxx() interfaces].
8888 ** In that case, [sqlite3_value_nochange(X)] will return true for the
8889 ** same column in the [xUpdate] method.
8890 */
8891 SQLITE_API int sqlite3_vtab_nochange(sqlite3_context*);
8892 
8893 /*
8894 ** CAPI3REF: Determine The Collation For a Virtual Table Constraint
8895 **
8896 ** This function may only be called from within a call to the [xBestIndex]
8897 ** method of a [virtual table].
8898 **
8899 ** The first argument must be the sqlite3_index_info object that is the
8900 ** first parameter to the xBestIndex() method. The second argument must be
8901 ** an index into the aConstraint[] array belonging to the sqlite3_index_info
8902 ** structure passed to xBestIndex. This function returns a pointer to a buffer
8903 ** containing the name of the collation sequence for the corresponding
8904 ** constraint.
8905 */
8906 SQLITE_API SQLITE_EXPERIMENTAL const char *sqlite3_vtab_collation(sqlite3_index_info*,int);
8907 
8908 /*
8909 ** CAPI3REF: Conflict resolution modes
8910 ** KEYWORDS: {conflict resolution mode}
8911 **
8912 ** These constants are returned by [sqlite3_vtab_on_conflict()] to
8913 ** inform a [virtual table] implementation what the [ON CONFLICT] mode
8914 ** is for the SQL statement being evaluated.
8915 **
8916 ** Note that the [SQLITE_IGNORE] constant is also used as a potential
8917 ** return value from the [sqlite3_set_authorizer()] callback and that
8918 ** [SQLITE_ABORT] is also a [result code].
8919 */
8920 #define SQLITE_ROLLBACK 1
8921 /* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
8922 #define SQLITE_FAIL     3
8923 /* #define SQLITE_ABORT 4  // Also an error code */
8924 #define SQLITE_REPLACE  5
8925 
8926 /*
8927 ** CAPI3REF: Prepared Statement Scan Status Opcodes
8928 ** KEYWORDS: {scanstatus options}
8929 **
8930 ** The following constants can be used for the T parameter to the
8931 ** [sqlite3_stmt_scanstatus(S,X,T,V)] interface.  Each constant designates a
8932 ** different metric for sqlite3_stmt_scanstatus() to return.
8933 **
8934 ** When the value returned to V is a string, space to hold that string is
8935 ** managed by the prepared statement S and will be automatically freed when
8936 ** S is finalized.
8937 **
8938 ** <dl>
8939 ** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt>
8940 ** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be
8941 ** set to the total number of times that the X-th loop has run.</dd>
8942 **
8943 ** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt>
8944 ** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set
8945 ** to the total number of rows examined by all iterations of the X-th loop.</dd>
8946 **
8947 ** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt>
8948 ** <dd>^The "double" variable pointed to by the T parameter will be set to the
8949 ** query planner's estimate for the average number of rows output from each
8950 ** iteration of the X-th loop.  If the query planner's estimates was accurate,
8951 ** then this value will approximate the quotient NVISIT/NLOOP and the
8952 ** product of this value for all prior loops with the same SELECTID will
8953 ** be the NLOOP value for the current loop.
8954 **
8955 ** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt>
8956 ** <dd>^The "const char *" variable pointed to by the T parameter will be set
8957 ** to a zero-terminated UTF-8 string containing the name of the index or table
8958 ** used for the X-th loop.
8959 **
8960 ** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt>
8961 ** <dd>^The "const char *" variable pointed to by the T parameter will be set
8962 ** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN]
8963 ** description for the X-th loop.
8964 **
8965 ** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt>
8966 ** <dd>^The "int" variable pointed to by the T parameter will be set to the
8967 ** "select-id" for the X-th loop.  The select-id identifies which query or
8968 ** subquery the loop is part of.  The main query has a select-id of zero.
8969 ** The select-id is the same value as is output in the first column
8970 ** of an [EXPLAIN QUERY PLAN] query.
8971 ** </dl>
8972 */
8973 #define SQLITE_SCANSTAT_NLOOP    0
8974 #define SQLITE_SCANSTAT_NVISIT   1
8975 #define SQLITE_SCANSTAT_EST      2
8976 #define SQLITE_SCANSTAT_NAME     3
8977 #define SQLITE_SCANSTAT_EXPLAIN  4
8978 #define SQLITE_SCANSTAT_SELECTID 5
8979 
8980 /*
8981 ** CAPI3REF: Prepared Statement Scan Status
8982 ** METHOD: sqlite3_stmt
8983 **
8984 ** This interface returns information about the predicted and measured
8985 ** performance for pStmt.  Advanced applications can use this
8986 ** interface to compare the predicted and the measured performance and
8987 ** issue warnings and/or rerun [ANALYZE] if discrepancies are found.
8988 **
8989 ** Since this interface is expected to be rarely used, it is only
8990 ** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS]
8991 ** compile-time option.
8992 **
8993 ** The "iScanStatusOp" parameter determines which status information to return.
8994 ** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior
8995 ** of this interface is undefined.
8996 ** ^The requested measurement is written into a variable pointed to by
8997 ** the "pOut" parameter.
8998 ** Parameter "idx" identifies the specific loop to retrieve statistics for.
8999 ** Loops are numbered starting from zero. ^If idx is out of range - less than
9000 ** zero or greater than or equal to the total number of loops used to implement
9001 ** the statement - a non-zero value is returned and the variable that pOut
9002 ** points to is unchanged.
9003 **
9004 ** ^Statistics might not be available for all loops in all statements. ^In cases
9005 ** where there exist loops with no available statistics, this function behaves
9006 ** as if the loop did not exist - it returns non-zero and leave the variable
9007 ** that pOut points to unchanged.
9008 **
9009 ** See also: [sqlite3_stmt_scanstatus_reset()]
9010 */
9011 SQLITE_API int sqlite3_stmt_scanstatus(
9012   sqlite3_stmt *pStmt,      /* Prepared statement for which info desired */
9013   int idx,                  /* Index of loop to report on */
9014   int iScanStatusOp,        /* Information desired.  SQLITE_SCANSTAT_* */
9015   void *pOut                /* Result written here */
9016 );
9017 
9018 /*
9019 ** CAPI3REF: Zero Scan-Status Counters
9020 ** METHOD: sqlite3_stmt
9021 **
9022 ** ^Zero all [sqlite3_stmt_scanstatus()] related event counters.
9023 **
9024 ** This API is only available if the library is built with pre-processor
9025 ** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined.
9026 */
9027 SQLITE_API void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*);
9028 
9029 /*
9030 ** CAPI3REF: Flush caches to disk mid-transaction
9031 **
9032 ** ^If a write-transaction is open on [database connection] D when the
9033 ** [sqlite3_db_cacheflush(D)] interface invoked, any dirty
9034 ** pages in the pager-cache that are not currently in use are written out
9035 ** to disk. A dirty page may be in use if a database cursor created by an
9036 ** active SQL statement is reading from it, or if it is page 1 of a database
9037 ** file (page 1 is always "in use").  ^The [sqlite3_db_cacheflush(D)]
9038 ** interface flushes caches for all schemas - "main", "temp", and
9039 ** any [attached] databases.
9040 **
9041 ** ^If this function needs to obtain extra database locks before dirty pages
9042 ** can be flushed to disk, it does so. ^If those locks cannot be obtained
9043 ** immediately and there is a busy-handler callback configured, it is invoked
9044 ** in the usual manner. ^If the required lock still cannot be obtained, then
9045 ** the database is skipped and an attempt made to flush any dirty pages
9046 ** belonging to the next (if any) database. ^If any databases are skipped
9047 ** because locks cannot be obtained, but no other error occurs, this
9048 ** function returns SQLITE_BUSY.
9049 **
9050 ** ^If any other error occurs while flushing dirty pages to disk (for
9051 ** example an IO error or out-of-memory condition), then processing is
9052 ** abandoned and an SQLite [error code] is returned to the caller immediately.
9053 **
9054 ** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK.
9055 **
9056 ** ^This function does not set the database handle error code or message
9057 ** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions.
9058 */
9059 SQLITE_API int sqlite3_db_cacheflush(sqlite3*);
9060 
9061 /*
9062 ** CAPI3REF: The pre-update hook.
9063 **
9064 ** ^These interfaces are only available if SQLite is compiled using the
9065 ** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option.
9066 **
9067 ** ^The [sqlite3_preupdate_hook()] interface registers a callback function
9068 ** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation
9069 ** on a database table.
9070 ** ^At most one preupdate hook may be registered at a time on a single
9071 ** [database connection]; each call to [sqlite3_preupdate_hook()] overrides
9072 ** the previous setting.
9073 ** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()]
9074 ** with a NULL pointer as the second parameter.
9075 ** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as
9076 ** the first parameter to callbacks.
9077 **
9078 ** ^The preupdate hook only fires for changes to real database tables; the
9079 ** preupdate hook is not invoked for changes to [virtual tables] or to
9080 ** system tables like sqlite_master or sqlite_stat1.
9081 **
9082 ** ^The second parameter to the preupdate callback is a pointer to
9083 ** the [database connection] that registered the preupdate hook.
9084 ** ^The third parameter to the preupdate callback is one of the constants
9085 ** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the
9086 ** kind of update operation that is about to occur.
9087 ** ^(The fourth parameter to the preupdate callback is the name of the
9088 ** database within the database connection that is being modified.  This
9089 ** will be "main" for the main database or "temp" for TEMP tables or
9090 ** the name given after the AS keyword in the [ATTACH] statement for attached
9091 ** databases.)^
9092 ** ^The fifth parameter to the preupdate callback is the name of the
9093 ** table that is being modified.
9094 **
9095 ** For an UPDATE or DELETE operation on a [rowid table], the sixth
9096 ** parameter passed to the preupdate callback is the initial [rowid] of the
9097 ** row being modified or deleted. For an INSERT operation on a rowid table,
9098 ** or any operation on a WITHOUT ROWID table, the value of the sixth
9099 ** parameter is undefined. For an INSERT or UPDATE on a rowid table the
9100 ** seventh parameter is the final rowid value of the row being inserted
9101 ** or updated. The value of the seventh parameter passed to the callback
9102 ** function is not defined for operations on WITHOUT ROWID tables, or for
9103 ** INSERT operations on rowid tables.
9104 **
9105 ** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()],
9106 ** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces
9107 ** provide additional information about a preupdate event. These routines
9108 ** may only be called from within a preupdate callback.  Invoking any of
9109 ** these routines from outside of a preupdate callback or with a
9110 ** [database connection] pointer that is different from the one supplied
9111 ** to the preupdate callback results in undefined and probably undesirable
9112 ** behavior.
9113 **
9114 ** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns
9115 ** in the row that is being inserted, updated, or deleted.
9116 **
9117 ** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to
9118 ** a [protected sqlite3_value] that contains the value of the Nth column of
9119 ** the table row before it is updated.  The N parameter must be between 0
9120 ** and one less than the number of columns or the behavior will be
9121 ** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE
9122 ** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the
9123 ** behavior is undefined.  The [sqlite3_value] that P points to
9124 ** will be destroyed when the preupdate callback returns.
9125 **
9126 ** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to
9127 ** a [protected sqlite3_value] that contains the value of the Nth column of
9128 ** the table row after it is updated.  The N parameter must be between 0
9129 ** and one less than the number of columns or the behavior will be
9130 ** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE
9131 ** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the
9132 ** behavior is undefined.  The [sqlite3_value] that P points to
9133 ** will be destroyed when the preupdate callback returns.
9134 **
9135 ** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate
9136 ** callback was invoked as a result of a direct insert, update, or delete
9137 ** operation; or 1 for inserts, updates, or deletes invoked by top-level
9138 ** triggers; or 2 for changes resulting from triggers called by top-level
9139 ** triggers; and so forth.
9140 **
9141 ** See also:  [sqlite3_update_hook()]
9142 */
9143 #if defined(SQLITE_ENABLE_PREUPDATE_HOOK)
9144 SQLITE_API void *sqlite3_preupdate_hook(
9145   sqlite3 *db,
9146   void(*xPreUpdate)(
9147     void *pCtx,                   /* Copy of third arg to preupdate_hook() */
9148     sqlite3 *db,                  /* Database handle */
9149     int op,                       /* SQLITE_UPDATE, DELETE or INSERT */
9150     char const *zDb,              /* Database name */
9151     char const *zName,            /* Table name */
9152     sqlite3_int64 iKey1,          /* Rowid of row about to be deleted/updated */
9153     sqlite3_int64 iKey2           /* New rowid value (for a rowid UPDATE) */
9154   ),
9155   void*
9156 );
9157 SQLITE_API int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **);
9158 SQLITE_API int sqlite3_preupdate_count(sqlite3 *);
9159 SQLITE_API int sqlite3_preupdate_depth(sqlite3 *);
9160 SQLITE_API int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **);
9161 #endif
9162 
9163 /*
9164 ** CAPI3REF: Low-level system error code
9165 **
9166 ** ^Attempt to return the underlying operating system error code or error
9167 ** number that caused the most recent I/O error or failure to open a file.
9168 ** The return value is OS-dependent.  For example, on unix systems, after
9169 ** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be
9170 ** called to get back the underlying "errno" that caused the problem, such
9171 ** as ENOSPC, EAUTH, EISDIR, and so forth.
9172 */
9173 SQLITE_API int sqlite3_system_errno(sqlite3*);
9174 
9175 /*
9176 ** CAPI3REF: Database Snapshot
9177 ** KEYWORDS: {snapshot} {sqlite3_snapshot}
9178 **
9179 ** An instance of the snapshot object records the state of a [WAL mode]
9180 ** database for some specific point in history.
9181 **
9182 ** In [WAL mode], multiple [database connections] that are open on the
9183 ** same database file can each be reading a different historical version
9184 ** of the database file.  When a [database connection] begins a read
9185 ** transaction, that connection sees an unchanging copy of the database
9186 ** as it existed for the point in time when the transaction first started.
9187 ** Subsequent changes to the database from other connections are not seen
9188 ** by the reader until a new read transaction is started.
9189 **
9190 ** The sqlite3_snapshot object records state information about an historical
9191 ** version of the database file so that it is possible to later open a new read
9192 ** transaction that sees that historical version of the database rather than
9193 ** the most recent version.
9194 */
9195 typedef struct sqlite3_snapshot {
9196   unsigned char hidden[48];
9197 } sqlite3_snapshot;
9198 
9199 /*
9200 ** CAPI3REF: Record A Database Snapshot
9201 ** CONSTRUCTOR: sqlite3_snapshot
9202 **
9203 ** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a
9204 ** new [sqlite3_snapshot] object that records the current state of
9205 ** schema S in database connection D.  ^On success, the
9206 ** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly
9207 ** created [sqlite3_snapshot] object into *P and returns SQLITE_OK.
9208 ** If there is not already a read-transaction open on schema S when
9209 ** this function is called, one is opened automatically.
9210 **
9211 ** The following must be true for this function to succeed. If any of
9212 ** the following statements are false when sqlite3_snapshot_get() is
9213 ** called, SQLITE_ERROR is returned. The final value of *P is undefined
9214 ** in this case.
9215 **
9216 ** <ul>
9217 **   <li> The database handle must not be in [autocommit mode].
9218 **
9219 **   <li> Schema S of [database connection] D must be a [WAL mode] database.
9220 **
9221 **   <li> There must not be a write transaction open on schema S of database
9222 **        connection D.
9223 **
9224 **   <li> One or more transactions must have been written to the current wal
9225 **        file since it was created on disk (by any connection). This means
9226 **        that a snapshot cannot be taken on a wal mode database with no wal
9227 **        file immediately after it is first opened. At least one transaction
9228 **        must be written to it first.
9229 ** </ul>
9230 **
9231 ** This function may also return SQLITE_NOMEM.  If it is called with the
9232 ** database handle in autocommit mode but fails for some other reason,
9233 ** whether or not a read transaction is opened on schema S is undefined.
9234 **
9235 ** The [sqlite3_snapshot] object returned from a successful call to
9236 ** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()]
9237 ** to avoid a memory leak.
9238 **
9239 ** The [sqlite3_snapshot_get()] interface is only available when the
9240 ** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
9241 */
9242 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_get(
9243   sqlite3 *db,
9244   const char *zSchema,
9245   sqlite3_snapshot **ppSnapshot
9246 );
9247 
9248 /*
9249 ** CAPI3REF: Start a read transaction on an historical snapshot
9250 ** METHOD: sqlite3_snapshot
9251 **
9252 ** ^The [sqlite3_snapshot_open(D,S,P)] interface either starts a new read
9253 ** transaction or upgrades an existing one for schema S of
9254 ** [database connection] D such that the read transaction refers to
9255 ** historical [snapshot] P, rather than the most recent change to the
9256 ** database. ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK
9257 ** on success or an appropriate [error code] if it fails.
9258 **
9259 ** ^In order to succeed, the database connection must not be in
9260 ** [autocommit mode] when [sqlite3_snapshot_open(D,S,P)] is called. If there
9261 ** is already a read transaction open on schema S, then the database handle
9262 ** must have no active statements (SELECT statements that have been passed
9263 ** to sqlite3_step() but not sqlite3_reset() or sqlite3_finalize()).
9264 ** SQLITE_ERROR is returned if either of these conditions is violated, or
9265 ** if schema S does not exist, or if the snapshot object is invalid.
9266 **
9267 ** ^A call to sqlite3_snapshot_open() will fail to open if the specified
9268 ** snapshot has been overwritten by a [checkpoint]. In this case
9269 ** SQLITE_ERROR_SNAPSHOT is returned.
9270 **
9271 ** If there is already a read transaction open when this function is
9272 ** invoked, then the same read transaction remains open (on the same
9273 ** database snapshot) if SQLITE_ERROR, SQLITE_BUSY or SQLITE_ERROR_SNAPSHOT
9274 ** is returned. If another error code - for example SQLITE_PROTOCOL or an
9275 ** SQLITE_IOERR error code - is returned, then the final state of the
9276 ** read transaction is undefined. If SQLITE_OK is returned, then the
9277 ** read transaction is now open on database snapshot P.
9278 **
9279 ** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the
9280 ** database connection D does not know that the database file for
9281 ** schema S is in [WAL mode].  A database connection might not know
9282 ** that the database file is in [WAL mode] if there has been no prior
9283 ** I/O on that database connection, or if the database entered [WAL mode]
9284 ** after the most recent I/O on the database connection.)^
9285 ** (Hint: Run "[PRAGMA application_id]" against a newly opened
9286 ** database connection in order to make it ready to use snapshots.)
9287 **
9288 ** The [sqlite3_snapshot_open()] interface is only available when the
9289 ** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
9290 */
9291 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_open(
9292   sqlite3 *db,
9293   const char *zSchema,
9294   sqlite3_snapshot *pSnapshot
9295 );
9296 
9297 /*
9298 ** CAPI3REF: Destroy a snapshot
9299 ** DESTRUCTOR: sqlite3_snapshot
9300 **
9301 ** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P.
9302 ** The application must eventually free every [sqlite3_snapshot] object
9303 ** using this routine to avoid a memory leak.
9304 **
9305 ** The [sqlite3_snapshot_free()] interface is only available when the
9306 ** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
9307 */
9308 SQLITE_API SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*);
9309 
9310 /*
9311 ** CAPI3REF: Compare the ages of two snapshot handles.
9312 ** METHOD: sqlite3_snapshot
9313 **
9314 ** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages
9315 ** of two valid snapshot handles.
9316 **
9317 ** If the two snapshot handles are not associated with the same database
9318 ** file, the result of the comparison is undefined.
9319 **
9320 ** Additionally, the result of the comparison is only valid if both of the
9321 ** snapshot handles were obtained by calling sqlite3_snapshot_get() since the
9322 ** last time the wal file was deleted. The wal file is deleted when the
9323 ** database is changed back to rollback mode or when the number of database
9324 ** clients drops to zero. If either snapshot handle was obtained before the
9325 ** wal file was last deleted, the value returned by this function
9326 ** is undefined.
9327 **
9328 ** Otherwise, this API returns a negative value if P1 refers to an older
9329 ** snapshot than P2, zero if the two handles refer to the same database
9330 ** snapshot, and a positive value if P1 is a newer snapshot than P2.
9331 **
9332 ** This interface is only available if SQLite is compiled with the
9333 ** [SQLITE_ENABLE_SNAPSHOT] option.
9334 */
9335 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp(
9336   sqlite3_snapshot *p1,
9337   sqlite3_snapshot *p2
9338 );
9339 
9340 /*
9341 ** CAPI3REF: Recover snapshots from a wal file
9342 ** METHOD: sqlite3_snapshot
9343 **
9344 ** If a [WAL file] remains on disk after all database connections close
9345 ** (either through the use of the [SQLITE_FCNTL_PERSIST_WAL] [file control]
9346 ** or because the last process to have the database opened exited without
9347 ** calling [sqlite3_close()]) and a new connection is subsequently opened
9348 ** on that database and [WAL file], the [sqlite3_snapshot_open()] interface
9349 ** will only be able to open the last transaction added to the WAL file
9350 ** even though the WAL file contains other valid transactions.
9351 **
9352 ** This function attempts to scan the WAL file associated with database zDb
9353 ** of database handle db and make all valid snapshots available to
9354 ** sqlite3_snapshot_open(). It is an error if there is already a read
9355 ** transaction open on the database, or if the database is not a WAL mode
9356 ** database.
9357 **
9358 ** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
9359 **
9360 ** This interface is only available if SQLite is compiled with the
9361 ** [SQLITE_ENABLE_SNAPSHOT] option.
9362 */
9363 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb);
9364 
9365 /*
9366 ** CAPI3REF: Serialize a database
9367 **
9368 ** The sqlite3_serialize(D,S,P,F) interface returns a pointer to memory
9369 ** that is a serialization of the S database on [database connection] D.
9370 ** If P is not a NULL pointer, then the size of the database in bytes
9371 ** is written into *P.
9372 **
9373 ** For an ordinary on-disk database file, the serialization is just a
9374 ** copy of the disk file.  For an in-memory database or a "TEMP" database,
9375 ** the serialization is the same sequence of bytes which would be written
9376 ** to disk if that database where backed up to disk.
9377 **
9378 ** The usual case is that sqlite3_serialize() copies the serialization of
9379 ** the database into memory obtained from [sqlite3_malloc64()] and returns
9380 ** a pointer to that memory.  The caller is responsible for freeing the
9381 ** returned value to avoid a memory leak.  However, if the F argument
9382 ** contains the SQLITE_SERIALIZE_NOCOPY bit, then no memory allocations
9383 ** are made, and the sqlite3_serialize() function will return a pointer
9384 ** to the contiguous memory representation of the database that SQLite
9385 ** is currently using for that database, or NULL if the no such contiguous
9386 ** memory representation of the database exists.  A contiguous memory
9387 ** representation of the database will usually only exist if there has
9388 ** been a prior call to [sqlite3_deserialize(D,S,...)] with the same
9389 ** values of D and S.
9390 ** The size of the database is written into *P even if the
9391 ** SQLITE_SERIALIZE_NOCOPY bit is set but no contiguous copy
9392 ** of the database exists.
9393 **
9394 ** A call to sqlite3_serialize(D,S,P,F) might return NULL even if the
9395 ** SQLITE_SERIALIZE_NOCOPY bit is omitted from argument F if a memory
9396 ** allocation error occurs.
9397 **
9398 ** This interface is only available if SQLite is compiled with the
9399 ** [SQLITE_ENABLE_DESERIALIZE] option.
9400 */
9401 SQLITE_API unsigned char *sqlite3_serialize(
9402   sqlite3 *db,           /* The database connection */
9403   const char *zSchema,   /* Which DB to serialize. ex: "main", "temp", ... */
9404   sqlite3_int64 *piSize, /* Write size of the DB here, if not NULL */
9405   unsigned int mFlags    /* Zero or more SQLITE_SERIALIZE_* flags */
9406 );
9407 
9408 /*
9409 ** CAPI3REF: Flags for sqlite3_serialize
9410 **
9411 ** Zero or more of the following constants can be OR-ed together for
9412 ** the F argument to [sqlite3_serialize(D,S,P,F)].
9413 **
9414 ** SQLITE_SERIALIZE_NOCOPY means that [sqlite3_serialize()] will return
9415 ** a pointer to contiguous in-memory database that it is currently using,
9416 ** without making a copy of the database.  If SQLite is not currently using
9417 ** a contiguous in-memory database, then this option causes
9418 ** [sqlite3_serialize()] to return a NULL pointer.  SQLite will only be
9419 ** using a contiguous in-memory database if it has been initialized by a
9420 ** prior call to [sqlite3_deserialize()].
9421 */
9422 #define SQLITE_SERIALIZE_NOCOPY 0x001   /* Do no memory allocations */
9423 
9424 /*
9425 ** CAPI3REF: Deserialize a database
9426 **
9427 ** The sqlite3_deserialize(D,S,P,N,M,F) interface causes the
9428 ** [database connection] D to disconnect from database S and then
9429 ** reopen S as an in-memory database based on the serialization contained
9430 ** in P.  The serialized database P is N bytes in size.  M is the size of
9431 ** the buffer P, which might be larger than N.  If M is larger than N, and
9432 ** the SQLITE_DESERIALIZE_READONLY bit is not set in F, then SQLite is
9433 ** permitted to add content to the in-memory database as long as the total
9434 ** size does not exceed M bytes.
9435 **
9436 ** If the SQLITE_DESERIALIZE_FREEONCLOSE bit is set in F, then SQLite will
9437 ** invoke sqlite3_free() on the serialization buffer when the database
9438 ** connection closes.  If the SQLITE_DESERIALIZE_RESIZEABLE bit is set, then
9439 ** SQLite will try to increase the buffer size using sqlite3_realloc64()
9440 ** if writes on the database cause it to grow larger than M bytes.
9441 **
9442 ** The sqlite3_deserialize() interface will fail with SQLITE_BUSY if the
9443 ** database is currently in a read transaction or is involved in a backup
9444 ** operation.
9445 **
9446 ** If sqlite3_deserialize(D,S,P,N,M,F) fails for any reason and if the
9447 ** SQLITE_DESERIALIZE_FREEONCLOSE bit is set in argument F, then
9448 ** [sqlite3_free()] is invoked on argument P prior to returning.
9449 **
9450 ** This interface is only available if SQLite is compiled with the
9451 ** [SQLITE_ENABLE_DESERIALIZE] option.
9452 */
9453 SQLITE_API int sqlite3_deserialize(
9454   sqlite3 *db,            /* The database connection */
9455   const char *zSchema,    /* Which DB to reopen with the deserialization */
9456   unsigned char *pData,   /* The serialized database content */
9457   sqlite3_int64 szDb,     /* Number bytes in the deserialization */
9458   sqlite3_int64 szBuf,    /* Total size of buffer pData[] */
9459   unsigned mFlags         /* Zero or more SQLITE_DESERIALIZE_* flags */
9460 );
9461 
9462 /*
9463 ** CAPI3REF: Flags for sqlite3_deserialize()
9464 **
9465 ** The following are allowed values for 6th argument (the F argument) to
9466 ** the [sqlite3_deserialize(D,S,P,N,M,F)] interface.
9467 **
9468 ** The SQLITE_DESERIALIZE_FREEONCLOSE means that the database serialization
9469 ** in the P argument is held in memory obtained from [sqlite3_malloc64()]
9470 ** and that SQLite should take ownership of this memory and automatically
9471 ** free it when it has finished using it.  Without this flag, the caller
9472 ** is responsible for freeing any dynamically allocated memory.
9473 **
9474 ** The SQLITE_DESERIALIZE_RESIZEABLE flag means that SQLite is allowed to
9475 ** grow the size of the database using calls to [sqlite3_realloc64()].  This
9476 ** flag should only be used if SQLITE_DESERIALIZE_FREEONCLOSE is also used.
9477 ** Without this flag, the deserialized database cannot increase in size beyond
9478 ** the number of bytes specified by the M parameter.
9479 **
9480 ** The SQLITE_DESERIALIZE_READONLY flag means that the deserialized database
9481 ** should be treated as read-only.
9482 */
9483 #define SQLITE_DESERIALIZE_FREEONCLOSE 1 /* Call sqlite3_free() on close */
9484 #define SQLITE_DESERIALIZE_RESIZEABLE  2 /* Resize using sqlite3_realloc64() */
9485 #define SQLITE_DESERIALIZE_READONLY    4 /* Database is read-only */
9486 
9487 /*
9488 ** Undo the hack that converts floating point types to integer for
9489 ** builds on processors without floating point support.
9490 */
9491 #ifdef SQLITE_OMIT_FLOATING_POINT
9492 # undef double
9493 #endif
9494 
9495 #ifdef __cplusplus
9496 }  /* End of the 'extern "C"' block */
9497 #endif
9498 #endif /* SQLITE3_H */
9499 
9500 /******** Begin file sqlite3rtree.h *********/
9501 /*
9502 ** 2010 August 30
9503 **
9504 ** The author disclaims copyright to this source code.  In place of
9505 ** a legal notice, here is a blessing:
9506 **
9507 **    May you do good and not evil.
9508 **    May you find forgiveness for yourself and forgive others.
9509 **    May you share freely, never taking more than you give.
9510 **
9511 *************************************************************************
9512 */
9513 
9514 #ifndef _SQLITE3RTREE_H_
9515 #define _SQLITE3RTREE_H_
9516 
9517 
9518 #ifdef __cplusplus
9519 extern "C" {
9520 #endif
9521 
9522 typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry;
9523 typedef struct sqlite3_rtree_query_info sqlite3_rtree_query_info;
9524 
9525 /* The double-precision datatype used by RTree depends on the
9526 ** SQLITE_RTREE_INT_ONLY compile-time option.
9527 */
9528 #ifdef SQLITE_RTREE_INT_ONLY
9529   typedef sqlite3_int64 sqlite3_rtree_dbl;
9530 #else
9531   typedef double sqlite3_rtree_dbl;
9532 #endif
9533 
9534 /*
9535 ** Register a geometry callback named zGeom that can be used as part of an
9536 ** R-Tree geometry query as follows:
9537 **
9538 **   SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...)
9539 */
9540 SQLITE_API int sqlite3_rtree_geometry_callback(
9541   sqlite3 *db,
9542   const char *zGeom,
9543   int (*xGeom)(sqlite3_rtree_geometry*, int, sqlite3_rtree_dbl*,int*),
9544   void *pContext
9545 );
9546 
9547 
9548 /*
9549 ** A pointer to a structure of the following type is passed as the first
9550 ** argument to callbacks registered using rtree_geometry_callback().
9551 */
9552 struct sqlite3_rtree_geometry {
9553   void *pContext;                 /* Copy of pContext passed to s_r_g_c() */
9554   int nParam;                     /* Size of array aParam[] */
9555   sqlite3_rtree_dbl *aParam;      /* Parameters passed to SQL geom function */
9556   void *pUser;                    /* Callback implementation user data */
9557   void (*xDelUser)(void *);       /* Called by SQLite to clean up pUser */
9558 };
9559 
9560 /*
9561 ** Register a 2nd-generation geometry callback named zScore that can be
9562 ** used as part of an R-Tree geometry query as follows:
9563 **
9564 **   SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zQueryFunc(... params ...)
9565 */
9566 SQLITE_API int sqlite3_rtree_query_callback(
9567   sqlite3 *db,
9568   const char *zQueryFunc,
9569   int (*xQueryFunc)(sqlite3_rtree_query_info*),
9570   void *pContext,
9571   void (*xDestructor)(void*)
9572 );
9573 
9574 
9575 /*
9576 ** A pointer to a structure of the following type is passed as the
9577 ** argument to scored geometry callback registered using
9578 ** sqlite3_rtree_query_callback().
9579 **
9580 ** Note that the first 5 fields of this structure are identical to
9581 ** sqlite3_rtree_geometry.  This structure is a subclass of
9582 ** sqlite3_rtree_geometry.
9583 */
9584 struct sqlite3_rtree_query_info {
9585   void *pContext;                   /* pContext from when function registered */
9586   int nParam;                       /* Number of function parameters */
9587   sqlite3_rtree_dbl *aParam;        /* value of function parameters */
9588   void *pUser;                      /* callback can use this, if desired */
9589   void (*xDelUser)(void*);          /* function to free pUser */
9590   sqlite3_rtree_dbl *aCoord;        /* Coordinates of node or entry to check */
9591   unsigned int *anQueue;            /* Number of pending entries in the queue */
9592   int nCoord;                       /* Number of coordinates */
9593   int iLevel;                       /* Level of current node or entry */
9594   int mxLevel;                      /* The largest iLevel value in the tree */
9595   sqlite3_int64 iRowid;             /* Rowid for current entry */
9596   sqlite3_rtree_dbl rParentScore;   /* Score of parent node */
9597   int eParentWithin;                /* Visibility of parent node */
9598   int eWithin;                      /* OUT: Visibility */
9599   sqlite3_rtree_dbl rScore;         /* OUT: Write the score here */
9600   /* The following fields are only available in 3.8.11 and later */
9601   sqlite3_value **apSqlParam;       /* Original SQL values of parameters */
9602 };
9603 
9604 /*
9605 ** Allowed values for sqlite3_rtree_query.eWithin and .eParentWithin.
9606 */
9607 #define NOT_WITHIN       0   /* Object completely outside of query region */
9608 #define PARTLY_WITHIN    1   /* Object partially overlaps query region */
9609 #define FULLY_WITHIN     2   /* Object fully contained within query region */
9610 
9611 
9612 #ifdef __cplusplus
9613 }  /* end of the 'extern "C"' block */
9614 #endif
9615 
9616 #endif  /* ifndef _SQLITE3RTREE_H_ */
9617 
9618 /******** End of sqlite3rtree.h *********/
9619 /******** Begin file sqlite3session.h *********/
9620 
9621 #if !defined(__SQLITESESSION_H_) && defined(SQLITE_ENABLE_SESSION)
9622 #define __SQLITESESSION_H_ 1
9623 
9624 /*
9625 ** Make sure we can call this stuff from C++.
9626 */
9627 #ifdef __cplusplus
9628 extern "C" {
9629 #endif
9630 
9631 
9632 /*
9633 ** CAPI3REF: Session Object Handle
9634 **
9635 ** An instance of this object is a [session] that can be used to
9636 ** record changes to a database.
9637 */
9638 typedef struct sqlite3_session sqlite3_session;
9639 
9640 /*
9641 ** CAPI3REF: Changeset Iterator Handle
9642 **
9643 ** An instance of this object acts as a cursor for iterating
9644 ** over the elements of a [changeset] or [patchset].
9645 */
9646 typedef struct sqlite3_changeset_iter sqlite3_changeset_iter;
9647 
9648 /*
9649 ** CAPI3REF: Create A New Session Object
9650 ** CONSTRUCTOR: sqlite3_session
9651 **
9652 ** Create a new session object attached to database handle db. If successful,
9653 ** a pointer to the new object is written to *ppSession and SQLITE_OK is
9654 ** returned. If an error occurs, *ppSession is set to NULL and an SQLite
9655 ** error code (e.g. SQLITE_NOMEM) is returned.
9656 **
9657 ** It is possible to create multiple session objects attached to a single
9658 ** database handle.
9659 **
9660 ** Session objects created using this function should be deleted using the
9661 ** [sqlite3session_delete()] function before the database handle that they
9662 ** are attached to is itself closed. If the database handle is closed before
9663 ** the session object is deleted, then the results of calling any session
9664 ** module function, including [sqlite3session_delete()] on the session object
9665 ** are undefined.
9666 **
9667 ** Because the session module uses the [sqlite3_preupdate_hook()] API, it
9668 ** is not possible for an application to register a pre-update hook on a
9669 ** database handle that has one or more session objects attached. Nor is
9670 ** it possible to create a session object attached to a database handle for
9671 ** which a pre-update hook is already defined. The results of attempting
9672 ** either of these things are undefined.
9673 **
9674 ** The session object will be used to create changesets for tables in
9675 ** database zDb, where zDb is either "main", or "temp", or the name of an
9676 ** attached database. It is not an error if database zDb is not attached
9677 ** to the database when the session object is created.
9678 */
9679 SQLITE_API int sqlite3session_create(
9680   sqlite3 *db,                    /* Database handle */
9681   const char *zDb,                /* Name of db (e.g. "main") */
9682   sqlite3_session **ppSession     /* OUT: New session object */
9683 );
9684 
9685 /*
9686 ** CAPI3REF: Delete A Session Object
9687 ** DESTRUCTOR: sqlite3_session
9688 **
9689 ** Delete a session object previously allocated using
9690 ** [sqlite3session_create()]. Once a session object has been deleted, the
9691 ** results of attempting to use pSession with any other session module
9692 ** function are undefined.
9693 **
9694 ** Session objects must be deleted before the database handle to which they
9695 ** are attached is closed. Refer to the documentation for
9696 ** [sqlite3session_create()] for details.
9697 */
9698 SQLITE_API void sqlite3session_delete(sqlite3_session *pSession);
9699 
9700 
9701 /*
9702 ** CAPI3REF: Enable Or Disable A Session Object
9703 ** METHOD: sqlite3_session
9704 **
9705 ** Enable or disable the recording of changes by a session object. When
9706 ** enabled, a session object records changes made to the database. When
9707 ** disabled - it does not. A newly created session object is enabled.
9708 ** Refer to the documentation for [sqlite3session_changeset()] for further
9709 ** details regarding how enabling and disabling a session object affects
9710 ** the eventual changesets.
9711 **
9712 ** Passing zero to this function disables the session. Passing a value
9713 ** greater than zero enables it. Passing a value less than zero is a
9714 ** no-op, and may be used to query the current state of the session.
9715 **
9716 ** The return value indicates the final state of the session object: 0 if
9717 ** the session is disabled, or 1 if it is enabled.
9718 */
9719 SQLITE_API int sqlite3session_enable(sqlite3_session *pSession, int bEnable);
9720 
9721 /*
9722 ** CAPI3REF: Set Or Clear the Indirect Change Flag
9723 ** METHOD: sqlite3_session
9724 **
9725 ** Each change recorded by a session object is marked as either direct or
9726 ** indirect. A change is marked as indirect if either:
9727 **
9728 ** <ul>
9729 **   <li> The session object "indirect" flag is set when the change is
9730 **        made, or
9731 **   <li> The change is made by an SQL trigger or foreign key action
9732 **        instead of directly as a result of a users SQL statement.
9733 ** </ul>
9734 **
9735 ** If a single row is affected by more than one operation within a session,
9736 ** then the change is considered indirect if all operations meet the criteria
9737 ** for an indirect change above, or direct otherwise.
9738 **
9739 ** This function is used to set, clear or query the session object indirect
9740 ** flag.  If the second argument passed to this function is zero, then the
9741 ** indirect flag is cleared. If it is greater than zero, the indirect flag
9742 ** is set. Passing a value less than zero does not modify the current value
9743 ** of the indirect flag, and may be used to query the current state of the
9744 ** indirect flag for the specified session object.
9745 **
9746 ** The return value indicates the final state of the indirect flag: 0 if
9747 ** it is clear, or 1 if it is set.
9748 */
9749 SQLITE_API int sqlite3session_indirect(sqlite3_session *pSession, int bIndirect);
9750 
9751 /*
9752 ** CAPI3REF: Attach A Table To A Session Object
9753 ** METHOD: sqlite3_session
9754 **
9755 ** If argument zTab is not NULL, then it is the name of a table to attach
9756 ** to the session object passed as the first argument. All subsequent changes
9757 ** made to the table while the session object is enabled will be recorded. See
9758 ** documentation for [sqlite3session_changeset()] for further details.
9759 **
9760 ** Or, if argument zTab is NULL, then changes are recorded for all tables
9761 ** in the database. If additional tables are added to the database (by
9762 ** executing "CREATE TABLE" statements) after this call is made, changes for
9763 ** the new tables are also recorded.
9764 **
9765 ** Changes can only be recorded for tables that have a PRIMARY KEY explicitly
9766 ** defined as part of their CREATE TABLE statement. It does not matter if the
9767 ** PRIMARY KEY is an "INTEGER PRIMARY KEY" (rowid alias) or not. The PRIMARY
9768 ** KEY may consist of a single column, or may be a composite key.
9769 **
9770 ** It is not an error if the named table does not exist in the database. Nor
9771 ** is it an error if the named table does not have a PRIMARY KEY. However,
9772 ** no changes will be recorded in either of these scenarios.
9773 **
9774 ** Changes are not recorded for individual rows that have NULL values stored
9775 ** in one or more of their PRIMARY KEY columns.
9776 **
9777 ** SQLITE_OK is returned if the call completes without error. Or, if an error
9778 ** occurs, an SQLite error code (e.g. SQLITE_NOMEM) is returned.
9779 **
9780 ** <h3>Special sqlite_stat1 Handling</h3>
9781 **
9782 ** As of SQLite version 3.22.0, the "sqlite_stat1" table is an exception to
9783 ** some of the rules above. In SQLite, the schema of sqlite_stat1 is:
9784 **  <pre>
9785 **  &nbsp;     CREATE TABLE sqlite_stat1(tbl,idx,stat)
9786 **  </pre>
9787 **
9788 ** Even though sqlite_stat1 does not have a PRIMARY KEY, changes are
9789 ** recorded for it as if the PRIMARY KEY is (tbl,idx). Additionally, changes
9790 ** are recorded for rows for which (idx IS NULL) is true. However, for such
9791 ** rows a zero-length blob (SQL value X'') is stored in the changeset or
9792 ** patchset instead of a NULL value. This allows such changesets to be
9793 ** manipulated by legacy implementations of sqlite3changeset_invert(),
9794 ** concat() and similar.
9795 **
9796 ** The sqlite3changeset_apply() function automatically converts the
9797 ** zero-length blob back to a NULL value when updating the sqlite_stat1
9798 ** table. However, if the application calls sqlite3changeset_new(),
9799 ** sqlite3changeset_old() or sqlite3changeset_conflict on a changeset
9800 ** iterator directly (including on a changeset iterator passed to a
9801 ** conflict-handler callback) then the X'' value is returned. The application
9802 ** must translate X'' to NULL itself if required.
9803 **
9804 ** Legacy (older than 3.22.0) versions of the sessions module cannot capture
9805 ** changes made to the sqlite_stat1 table. Legacy versions of the
9806 ** sqlite3changeset_apply() function silently ignore any modifications to the
9807 ** sqlite_stat1 table that are part of a changeset or patchset.
9808 */
9809 SQLITE_API int sqlite3session_attach(
9810   sqlite3_session *pSession,      /* Session object */
9811   const char *zTab                /* Table name */
9812 );
9813 
9814 /*
9815 ** CAPI3REF: Set a table filter on a Session Object.
9816 ** METHOD: sqlite3_session
9817 **
9818 ** The second argument (xFilter) is the "filter callback". For changes to rows
9819 ** in tables that are not attached to the Session object, the filter is called
9820 ** to determine whether changes to the table's rows should be tracked or not.
9821 ** If xFilter returns 0, changes is not tracked. Note that once a table is
9822 ** attached, xFilter will not be called again.
9823 */
9824 SQLITE_API void sqlite3session_table_filter(
9825   sqlite3_session *pSession,      /* Session object */
9826   int(*xFilter)(
9827     void *pCtx,                   /* Copy of third arg to _filter_table() */
9828     const char *zTab              /* Table name */
9829   ),
9830   void *pCtx                      /* First argument passed to xFilter */
9831 );
9832 
9833 /*
9834 ** CAPI3REF: Generate A Changeset From A Session Object
9835 ** METHOD: sqlite3_session
9836 **
9837 ** Obtain a changeset containing changes to the tables attached to the
9838 ** session object passed as the first argument. If successful,
9839 ** set *ppChangeset to point to a buffer containing the changeset
9840 ** and *pnChangeset to the size of the changeset in bytes before returning
9841 ** SQLITE_OK. If an error occurs, set both *ppChangeset and *pnChangeset to
9842 ** zero and return an SQLite error code.
9843 **
9844 ** A changeset consists of zero or more INSERT, UPDATE and/or DELETE changes,
9845 ** each representing a change to a single row of an attached table. An INSERT
9846 ** change contains the values of each field of a new database row. A DELETE
9847 ** contains the original values of each field of a deleted database row. An
9848 ** UPDATE change contains the original values of each field of an updated
9849 ** database row along with the updated values for each updated non-primary-key
9850 ** column. It is not possible for an UPDATE change to represent a change that
9851 ** modifies the values of primary key columns. If such a change is made, it
9852 ** is represented in a changeset as a DELETE followed by an INSERT.
9853 **
9854 ** Changes are not recorded for rows that have NULL values stored in one or
9855 ** more of their PRIMARY KEY columns. If such a row is inserted or deleted,
9856 ** no corresponding change is present in the changesets returned by this
9857 ** function. If an existing row with one or more NULL values stored in
9858 ** PRIMARY KEY columns is updated so that all PRIMARY KEY columns are non-NULL,
9859 ** only an INSERT is appears in the changeset. Similarly, if an existing row
9860 ** with non-NULL PRIMARY KEY values is updated so that one or more of its
9861 ** PRIMARY KEY columns are set to NULL, the resulting changeset contains a
9862 ** DELETE change only.
9863 **
9864 ** The contents of a changeset may be traversed using an iterator created
9865 ** using the [sqlite3changeset_start()] API. A changeset may be applied to
9866 ** a database with a compatible schema using the [sqlite3changeset_apply()]
9867 ** API.
9868 **
9869 ** Within a changeset generated by this function, all changes related to a
9870 ** single table are grouped together. In other words, when iterating through
9871 ** a changeset or when applying a changeset to a database, all changes related
9872 ** to a single table are processed before moving on to the next table. Tables
9873 ** are sorted in the same order in which they were attached (or auto-attached)
9874 ** to the sqlite3_session object. The order in which the changes related to
9875 ** a single table are stored is undefined.
9876 **
9877 ** Following a successful call to this function, it is the responsibility of
9878 ** the caller to eventually free the buffer that *ppChangeset points to using
9879 ** [sqlite3_free()].
9880 **
9881 ** <h3>Changeset Generation</h3>
9882 **
9883 ** Once a table has been attached to a session object, the session object
9884 ** records the primary key values of all new rows inserted into the table.
9885 ** It also records the original primary key and other column values of any
9886 ** deleted or updated rows. For each unique primary key value, data is only
9887 ** recorded once - the first time a row with said primary key is inserted,
9888 ** updated or deleted in the lifetime of the session.
9889 **
9890 ** There is one exception to the previous paragraph: when a row is inserted,
9891 ** updated or deleted, if one or more of its primary key columns contain a
9892 ** NULL value, no record of the change is made.
9893 **
9894 ** The session object therefore accumulates two types of records - those
9895 ** that consist of primary key values only (created when the user inserts
9896 ** a new record) and those that consist of the primary key values and the
9897 ** original values of other table columns (created when the users deletes
9898 ** or updates a record).
9899 **
9900 ** When this function is called, the requested changeset is created using
9901 ** both the accumulated records and the current contents of the database
9902 ** file. Specifically:
9903 **
9904 ** <ul>
9905 **   <li> For each record generated by an insert, the database is queried
9906 **        for a row with a matching primary key. If one is found, an INSERT
9907 **        change is added to the changeset. If no such row is found, no change
9908 **        is added to the changeset.
9909 **
9910 **   <li> For each record generated by an update or delete, the database is
9911 **        queried for a row with a matching primary key. If such a row is
9912 **        found and one or more of the non-primary key fields have been
9913 **        modified from their original values, an UPDATE change is added to
9914 **        the changeset. Or, if no such row is found in the table, a DELETE
9915 **        change is added to the changeset. If there is a row with a matching
9916 **        primary key in the database, but all fields contain their original
9917 **        values, no change is added to the changeset.
9918 ** </ul>
9919 **
9920 ** This means, amongst other things, that if a row is inserted and then later
9921 ** deleted while a session object is active, neither the insert nor the delete
9922 ** will be present in the changeset. Or if a row is deleted and then later a
9923 ** row with the same primary key values inserted while a session object is
9924 ** active, the resulting changeset will contain an UPDATE change instead of
9925 ** a DELETE and an INSERT.
9926 **
9927 ** When a session object is disabled (see the [sqlite3session_enable()] API),
9928 ** it does not accumulate records when rows are inserted, updated or deleted.
9929 ** This may appear to have some counter-intuitive effects if a single row
9930 ** is written to more than once during a session. For example, if a row
9931 ** is inserted while a session object is enabled, then later deleted while
9932 ** the same session object is disabled, no INSERT record will appear in the
9933 ** changeset, even though the delete took place while the session was disabled.
9934 ** Or, if one field of a row is updated while a session is disabled, and
9935 ** another field of the same row is updated while the session is enabled, the
9936 ** resulting changeset will contain an UPDATE change that updates both fields.
9937 */
9938 SQLITE_API int sqlite3session_changeset(
9939   sqlite3_session *pSession,      /* Session object */
9940   int *pnChangeset,               /* OUT: Size of buffer at *ppChangeset */
9941   void **ppChangeset              /* OUT: Buffer containing changeset */
9942 );
9943 
9944 /*
9945 ** CAPI3REF: Load The Difference Between Tables Into A Session
9946 ** METHOD: sqlite3_session
9947 **
9948 ** If it is not already attached to the session object passed as the first
9949 ** argument, this function attaches table zTbl in the same manner as the
9950 ** [sqlite3session_attach()] function. If zTbl does not exist, or if it
9951 ** does not have a primary key, this function is a no-op (but does not return
9952 ** an error).
9953 **
9954 ** Argument zFromDb must be the name of a database ("main", "temp" etc.)
9955 ** attached to the same database handle as the session object that contains
9956 ** a table compatible with the table attached to the session by this function.
9957 ** A table is considered compatible if it:
9958 **
9959 ** <ul>
9960 **   <li> Has the same name,
9961 **   <li> Has the same set of columns declared in the same order, and
9962 **   <li> Has the same PRIMARY KEY definition.
9963 ** </ul>
9964 **
9965 ** If the tables are not compatible, SQLITE_SCHEMA is returned. If the tables
9966 ** are compatible but do not have any PRIMARY KEY columns, it is not an error
9967 ** but no changes are added to the session object. As with other session
9968 ** APIs, tables without PRIMARY KEYs are simply ignored.
9969 **
9970 ** This function adds a set of changes to the session object that could be
9971 ** used to update the table in database zFrom (call this the "from-table")
9972 ** so that its content is the same as the table attached to the session
9973 ** object (call this the "to-table"). Specifically:
9974 **
9975 ** <ul>
9976 **   <li> For each row (primary key) that exists in the to-table but not in
9977 **     the from-table, an INSERT record is added to the session object.
9978 **
9979 **   <li> For each row (primary key) that exists in the to-table but not in
9980 **     the from-table, a DELETE record is added to the session object.
9981 **
9982 **   <li> For each row (primary key) that exists in both tables, but features
9983 **     different non-PK values in each, an UPDATE record is added to the
9984 **     session.
9985 ** </ul>
9986 **
9987 ** To clarify, if this function is called and then a changeset constructed
9988 ** using [sqlite3session_changeset()], then after applying that changeset to
9989 ** database zFrom the contents of the two compatible tables would be
9990 ** identical.
9991 **
9992 ** It an error if database zFrom does not exist or does not contain the
9993 ** required compatible table.
9994 **
9995 ** If the operation successful, SQLITE_OK is returned. Otherwise, an SQLite
9996 ** error code. In this case, if argument pzErrMsg is not NULL, *pzErrMsg
9997 ** may be set to point to a buffer containing an English language error
9998 ** message. It is the responsibility of the caller to free this buffer using
9999 ** sqlite3_free().
10000 */
10001 SQLITE_API int sqlite3session_diff(
10002   sqlite3_session *pSession,
10003   const char *zFromDb,
10004   const char *zTbl,
10005   char **pzErrMsg
10006 );
10007 
10008 
10009 /*
10010 ** CAPI3REF: Generate A Patchset From A Session Object
10011 ** METHOD: sqlite3_session
10012 **
10013 ** The differences between a patchset and a changeset are that:
10014 **
10015 ** <ul>
10016 **   <li> DELETE records consist of the primary key fields only. The
10017 **        original values of other fields are omitted.
10018 **   <li> The original values of any modified fields are omitted from
10019 **        UPDATE records.
10020 ** </ul>
10021 **
10022 ** A patchset blob may be used with up to date versions of all
10023 ** sqlite3changeset_xxx API functions except for sqlite3changeset_invert(),
10024 ** which returns SQLITE_CORRUPT if it is passed a patchset. Similarly,
10025 ** attempting to use a patchset blob with old versions of the
10026 ** sqlite3changeset_xxx APIs also provokes an SQLITE_CORRUPT error.
10027 **
10028 ** Because the non-primary key "old.*" fields are omitted, no
10029 ** SQLITE_CHANGESET_DATA conflicts can be detected or reported if a patchset
10030 ** is passed to the sqlite3changeset_apply() API. Other conflict types work
10031 ** in the same way as for changesets.
10032 **
10033 ** Changes within a patchset are ordered in the same way as for changesets
10034 ** generated by the sqlite3session_changeset() function (i.e. all changes for
10035 ** a single table are grouped together, tables appear in the order in which
10036 ** they were attached to the session object).
10037 */
10038 SQLITE_API int sqlite3session_patchset(
10039   sqlite3_session *pSession,      /* Session object */
10040   int *pnPatchset,                /* OUT: Size of buffer at *ppPatchset */
10041   void **ppPatchset               /* OUT: Buffer containing patchset */
10042 );
10043 
10044 /*
10045 ** CAPI3REF: Test if a changeset has recorded any changes.
10046 **
10047 ** Return non-zero if no changes to attached tables have been recorded by
10048 ** the session object passed as the first argument. Otherwise, if one or
10049 ** more changes have been recorded, return zero.
10050 **
10051 ** Even if this function returns zero, it is possible that calling
10052 ** [sqlite3session_changeset()] on the session handle may still return a
10053 ** changeset that contains no changes. This can happen when a row in
10054 ** an attached table is modified and then later on the original values
10055 ** are restored. However, if this function returns non-zero, then it is
10056 ** guaranteed that a call to sqlite3session_changeset() will return a
10057 ** changeset containing zero changes.
10058 */
10059 SQLITE_API int sqlite3session_isempty(sqlite3_session *pSession);
10060 
10061 /*
10062 ** CAPI3REF: Create An Iterator To Traverse A Changeset
10063 ** CONSTRUCTOR: sqlite3_changeset_iter
10064 **
10065 ** Create an iterator used to iterate through the contents of a changeset.
10066 ** If successful, *pp is set to point to the iterator handle and SQLITE_OK
10067 ** is returned. Otherwise, if an error occurs, *pp is set to zero and an
10068 ** SQLite error code is returned.
10069 **
10070 ** The following functions can be used to advance and query a changeset
10071 ** iterator created by this function:
10072 **
10073 ** <ul>
10074 **   <li> [sqlite3changeset_next()]
10075 **   <li> [sqlite3changeset_op()]
10076 **   <li> [sqlite3changeset_new()]
10077 **   <li> [sqlite3changeset_old()]
10078 ** </ul>
10079 **
10080 ** It is the responsibility of the caller to eventually destroy the iterator
10081 ** by passing it to [sqlite3changeset_finalize()]. The buffer containing the
10082 ** changeset (pChangeset) must remain valid until after the iterator is
10083 ** destroyed.
10084 **
10085 ** Assuming the changeset blob was created by one of the
10086 ** [sqlite3session_changeset()], [sqlite3changeset_concat()] or
10087 ** [sqlite3changeset_invert()] functions, all changes within the changeset
10088 ** that apply to a single table are grouped together. This means that when
10089 ** an application iterates through a changeset using an iterator created by
10090 ** this function, all changes that relate to a single table are visited
10091 ** consecutively. There is no chance that the iterator will visit a change
10092 ** the applies to table X, then one for table Y, and then later on visit
10093 ** another change for table X.
10094 **
10095 ** The behavior of sqlite3changeset_start_v2() and its streaming equivalent
10096 ** may be modified by passing a combination of
10097 ** [SQLITE_CHANGESETSTART_INVERT | supported flags] as the 4th parameter.
10098 **
10099 ** Note that the sqlite3changeset_start_v2() API is still <b>experimental</b>
10100 ** and therefore subject to change.
10101 */
10102 SQLITE_API int sqlite3changeset_start(
10103   sqlite3_changeset_iter **pp,    /* OUT: New changeset iterator handle */
10104   int nChangeset,                 /* Size of changeset blob in bytes */
10105   void *pChangeset                /* Pointer to blob containing changeset */
10106 );
10107 SQLITE_API int sqlite3changeset_start_v2(
10108   sqlite3_changeset_iter **pp,    /* OUT: New changeset iterator handle */
10109   int nChangeset,                 /* Size of changeset blob in bytes */
10110   void *pChangeset,               /* Pointer to blob containing changeset */
10111   int flags                       /* SESSION_CHANGESETSTART_* flags */
10112 );
10113 
10114 /*
10115 ** CAPI3REF: Flags for sqlite3changeset_start_v2
10116 **
10117 ** The following flags may passed via the 4th parameter to
10118 ** [sqlite3changeset_start_v2] and [sqlite3changeset_start_v2_strm]:
10119 **
10120 ** <dt>SQLITE_CHANGESETAPPLY_INVERT <dd>
10121 **   Invert the changeset while iterating through it. This is equivalent to
10122 **   inverting a changeset using sqlite3changeset_invert() before applying it.
10123 **   It is an error to specify this flag with a patchset.
10124 */
10125 #define SQLITE_CHANGESETSTART_INVERT        0x0002
10126 
10127 
10128 /*
10129 ** CAPI3REF: Advance A Changeset Iterator
10130 ** METHOD: sqlite3_changeset_iter
10131 **
10132 ** This function may only be used with iterators created by function
10133 ** [sqlite3changeset_start()]. If it is called on an iterator passed to
10134 ** a conflict-handler callback by [sqlite3changeset_apply()], SQLITE_MISUSE
10135 ** is returned and the call has no effect.
10136 **
10137 ** Immediately after an iterator is created by sqlite3changeset_start(), it
10138 ** does not point to any change in the changeset. Assuming the changeset
10139 ** is not empty, the first call to this function advances the iterator to
10140 ** point to the first change in the changeset. Each subsequent call advances
10141 ** the iterator to point to the next change in the changeset (if any). If
10142 ** no error occurs and the iterator points to a valid change after a call
10143 ** to sqlite3changeset_next() has advanced it, SQLITE_ROW is returned.
10144 ** Otherwise, if all changes in the changeset have already been visited,
10145 ** SQLITE_DONE is returned.
10146 **
10147 ** If an error occurs, an SQLite error code is returned. Possible error
10148 ** codes include SQLITE_CORRUPT (if the changeset buffer is corrupt) or
10149 ** SQLITE_NOMEM.
10150 */
10151 SQLITE_API int sqlite3changeset_next(sqlite3_changeset_iter *pIter);
10152 
10153 /*
10154 ** CAPI3REF: Obtain The Current Operation From A Changeset Iterator
10155 ** METHOD: sqlite3_changeset_iter
10156 **
10157 ** The pIter argument passed to this function may either be an iterator
10158 ** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
10159 ** created by [sqlite3changeset_start()]. In the latter case, the most recent
10160 ** call to [sqlite3changeset_next()] must have returned [SQLITE_ROW]. If this
10161 ** is not the case, this function returns [SQLITE_MISUSE].
10162 **
10163 ** If argument pzTab is not NULL, then *pzTab is set to point to a
10164 ** nul-terminated utf-8 encoded string containing the name of the table
10165 ** affected by the current change. The buffer remains valid until either
10166 ** sqlite3changeset_next() is called on the iterator or until the
10167 ** conflict-handler function returns. If pnCol is not NULL, then *pnCol is
10168 ** set to the number of columns in the table affected by the change. If
10169 ** pbIndirect is not NULL, then *pbIndirect is set to true (1) if the change
10170 ** is an indirect change, or false (0) otherwise. See the documentation for
10171 ** [sqlite3session_indirect()] for a description of direct and indirect
10172 ** changes. Finally, if pOp is not NULL, then *pOp is set to one of
10173 ** [SQLITE_INSERT], [SQLITE_DELETE] or [SQLITE_UPDATE], depending on the
10174 ** type of change that the iterator currently points to.
10175 **
10176 ** If no error occurs, SQLITE_OK is returned. If an error does occur, an
10177 ** SQLite error code is returned. The values of the output variables may not
10178 ** be trusted in this case.
10179 */
10180 SQLITE_API int sqlite3changeset_op(
10181   sqlite3_changeset_iter *pIter,  /* Iterator object */
10182   const char **pzTab,             /* OUT: Pointer to table name */
10183   int *pnCol,                     /* OUT: Number of columns in table */
10184   int *pOp,                       /* OUT: SQLITE_INSERT, DELETE or UPDATE */
10185   int *pbIndirect                 /* OUT: True for an 'indirect' change */
10186 );
10187 
10188 /*
10189 ** CAPI3REF: Obtain The Primary Key Definition Of A Table
10190 ** METHOD: sqlite3_changeset_iter
10191 **
10192 ** For each modified table, a changeset includes the following:
10193 **
10194 ** <ul>
10195 **   <li> The number of columns in the table, and
10196 **   <li> Which of those columns make up the tables PRIMARY KEY.
10197 ** </ul>
10198 **
10199 ** This function is used to find which columns comprise the PRIMARY KEY of
10200 ** the table modified by the change that iterator pIter currently points to.
10201 ** If successful, *pabPK is set to point to an array of nCol entries, where
10202 ** nCol is the number of columns in the table. Elements of *pabPK are set to
10203 ** 0x01 if the corresponding column is part of the tables primary key, or
10204 ** 0x00 if it is not.
10205 **
10206 ** If argument pnCol is not NULL, then *pnCol is set to the number of columns
10207 ** in the table.
10208 **
10209 ** If this function is called when the iterator does not point to a valid
10210 ** entry, SQLITE_MISUSE is returned and the output variables zeroed. Otherwise,
10211 ** SQLITE_OK is returned and the output variables populated as described
10212 ** above.
10213 */
10214 SQLITE_API int sqlite3changeset_pk(
10215   sqlite3_changeset_iter *pIter,  /* Iterator object */
10216   unsigned char **pabPK,          /* OUT: Array of boolean - true for PK cols */
10217   int *pnCol                      /* OUT: Number of entries in output array */
10218 );
10219 
10220 /*
10221 ** CAPI3REF: Obtain old.* Values From A Changeset Iterator
10222 ** METHOD: sqlite3_changeset_iter
10223 **
10224 ** The pIter argument passed to this function may either be an iterator
10225 ** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
10226 ** created by [sqlite3changeset_start()]. In the latter case, the most recent
10227 ** call to [sqlite3changeset_next()] must have returned SQLITE_ROW.
10228 ** Furthermore, it may only be called if the type of change that the iterator
10229 ** currently points to is either [SQLITE_DELETE] or [SQLITE_UPDATE]. Otherwise,
10230 ** this function returns [SQLITE_MISUSE] and sets *ppValue to NULL.
10231 **
10232 ** Argument iVal must be greater than or equal to 0, and less than the number
10233 ** of columns in the table affected by the current change. Otherwise,
10234 ** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
10235 **
10236 ** If successful, this function sets *ppValue to point to a protected
10237 ** sqlite3_value object containing the iVal'th value from the vector of
10238 ** original row values stored as part of the UPDATE or DELETE change and
10239 ** returns SQLITE_OK. The name of the function comes from the fact that this
10240 ** is similar to the "old.*" columns available to update or delete triggers.
10241 **
10242 ** If some other error occurs (e.g. an OOM condition), an SQLite error code
10243 ** is returned and *ppValue is set to NULL.
10244 */
10245 SQLITE_API int sqlite3changeset_old(
10246   sqlite3_changeset_iter *pIter,  /* Changeset iterator */
10247   int iVal,                       /* Column number */
10248   sqlite3_value **ppValue         /* OUT: Old value (or NULL pointer) */
10249 );
10250 
10251 /*
10252 ** CAPI3REF: Obtain new.* Values From A Changeset Iterator
10253 ** METHOD: sqlite3_changeset_iter
10254 **
10255 ** The pIter argument passed to this function may either be an iterator
10256 ** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
10257 ** created by [sqlite3changeset_start()]. In the latter case, the most recent
10258 ** call to [sqlite3changeset_next()] must have returned SQLITE_ROW.
10259 ** Furthermore, it may only be called if the type of change that the iterator
10260 ** currently points to is either [SQLITE_UPDATE] or [SQLITE_INSERT]. Otherwise,
10261 ** this function returns [SQLITE_MISUSE] and sets *ppValue to NULL.
10262 **
10263 ** Argument iVal must be greater than or equal to 0, and less than the number
10264 ** of columns in the table affected by the current change. Otherwise,
10265 ** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
10266 **
10267 ** If successful, this function sets *ppValue to point to a protected
10268 ** sqlite3_value object containing the iVal'th value from the vector of
10269 ** new row values stored as part of the UPDATE or INSERT change and
10270 ** returns SQLITE_OK. If the change is an UPDATE and does not include
10271 ** a new value for the requested column, *ppValue is set to NULL and
10272 ** SQLITE_OK returned. The name of the function comes from the fact that
10273 ** this is similar to the "new.*" columns available to update or delete
10274 ** triggers.
10275 **
10276 ** If some other error occurs (e.g. an OOM condition), an SQLite error code
10277 ** is returned and *ppValue is set to NULL.
10278 */
10279 SQLITE_API int sqlite3changeset_new(
10280   sqlite3_changeset_iter *pIter,  /* Changeset iterator */
10281   int iVal,                       /* Column number */
10282   sqlite3_value **ppValue         /* OUT: New value (or NULL pointer) */
10283 );
10284 
10285 /*
10286 ** CAPI3REF: Obtain Conflicting Row Values From A Changeset Iterator
10287 ** METHOD: sqlite3_changeset_iter
10288 **
10289 ** This function should only be used with iterator objects passed to a
10290 ** conflict-handler callback by [sqlite3changeset_apply()] with either
10291 ** [SQLITE_CHANGESET_DATA] or [SQLITE_CHANGESET_CONFLICT]. If this function
10292 ** is called on any other iterator, [SQLITE_MISUSE] is returned and *ppValue
10293 ** is set to NULL.
10294 **
10295 ** Argument iVal must be greater than or equal to 0, and less than the number
10296 ** of columns in the table affected by the current change. Otherwise,
10297 ** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
10298 **
10299 ** If successful, this function sets *ppValue to point to a protected
10300 ** sqlite3_value object containing the iVal'th value from the
10301 ** "conflicting row" associated with the current conflict-handler callback
10302 ** and returns SQLITE_OK.
10303 **
10304 ** If some other error occurs (e.g. an OOM condition), an SQLite error code
10305 ** is returned and *ppValue is set to NULL.
10306 */
10307 SQLITE_API int sqlite3changeset_conflict(
10308   sqlite3_changeset_iter *pIter,  /* Changeset iterator */
10309   int iVal,                       /* Column number */
10310   sqlite3_value **ppValue         /* OUT: Value from conflicting row */
10311 );
10312 
10313 /*
10314 ** CAPI3REF: Determine The Number Of Foreign Key Constraint Violations
10315 ** METHOD: sqlite3_changeset_iter
10316 **
10317 ** This function may only be called with an iterator passed to an
10318 ** SQLITE_CHANGESET_FOREIGN_KEY conflict handler callback. In this case
10319 ** it sets the output variable to the total number of known foreign key
10320 ** violations in the destination database and returns SQLITE_OK.
10321 **
10322 ** In all other cases this function returns SQLITE_MISUSE.
10323 */
10324 SQLITE_API int sqlite3changeset_fk_conflicts(
10325   sqlite3_changeset_iter *pIter,  /* Changeset iterator */
10326   int *pnOut                      /* OUT: Number of FK violations */
10327 );
10328 
10329 
10330 /*
10331 ** CAPI3REF: Finalize A Changeset Iterator
10332 ** METHOD: sqlite3_changeset_iter
10333 **
10334 ** This function is used to finalize an iterator allocated with
10335 ** [sqlite3changeset_start()].
10336 **
10337 ** This function should only be called on iterators created using the
10338 ** [sqlite3changeset_start()] function. If an application calls this
10339 ** function with an iterator passed to a conflict-handler by
10340 ** [sqlite3changeset_apply()], [SQLITE_MISUSE] is immediately returned and the
10341 ** call has no effect.
10342 **
10343 ** If an error was encountered within a call to an sqlite3changeset_xxx()
10344 ** function (for example an [SQLITE_CORRUPT] in [sqlite3changeset_next()] or an
10345 ** [SQLITE_NOMEM] in [sqlite3changeset_new()]) then an error code corresponding
10346 ** to that error is returned by this function. Otherwise, SQLITE_OK is
10347 ** returned. This is to allow the following pattern (pseudo-code):
10348 **
10349 ** <pre>
10350 **   sqlite3changeset_start();
10351 **   while( SQLITE_ROW==sqlite3changeset_next() ){
10352 **     // Do something with change.
10353 **   }
10354 **   rc = sqlite3changeset_finalize();
10355 **   if( rc!=SQLITE_OK ){
10356 **     // An error has occurred
10357 **   }
10358 ** </pre>
10359 */
10360 SQLITE_API int sqlite3changeset_finalize(sqlite3_changeset_iter *pIter);
10361 
10362 /*
10363 ** CAPI3REF: Invert A Changeset
10364 **
10365 ** This function is used to "invert" a changeset object. Applying an inverted
10366 ** changeset to a database reverses the effects of applying the uninverted
10367 ** changeset. Specifically:
10368 **
10369 ** <ul>
10370 **   <li> Each DELETE change is changed to an INSERT, and
10371 **   <li> Each INSERT change is changed to a DELETE, and
10372 **   <li> For each UPDATE change, the old.* and new.* values are exchanged.
10373 ** </ul>
10374 **
10375 ** This function does not change the order in which changes appear within
10376 ** the changeset. It merely reverses the sense of each individual change.
10377 **
10378 ** If successful, a pointer to a buffer containing the inverted changeset
10379 ** is stored in *ppOut, the size of the same buffer is stored in *pnOut, and
10380 ** SQLITE_OK is returned. If an error occurs, both *pnOut and *ppOut are
10381 ** zeroed and an SQLite error code returned.
10382 **
10383 ** It is the responsibility of the caller to eventually call sqlite3_free()
10384 ** on the *ppOut pointer to free the buffer allocation following a successful
10385 ** call to this function.
10386 **
10387 ** WARNING/TODO: This function currently assumes that the input is a valid
10388 ** changeset. If it is not, the results are undefined.
10389 */
10390 SQLITE_API int sqlite3changeset_invert(
10391   int nIn, const void *pIn,       /* Input changeset */
10392   int *pnOut, void **ppOut        /* OUT: Inverse of input */
10393 );
10394 
10395 /*
10396 ** CAPI3REF: Concatenate Two Changeset Objects
10397 **
10398 ** This function is used to concatenate two changesets, A and B, into a
10399 ** single changeset. The result is a changeset equivalent to applying
10400 ** changeset A followed by changeset B.
10401 **
10402 ** This function combines the two input changesets using an
10403 ** sqlite3_changegroup object. Calling it produces similar results as the
10404 ** following code fragment:
10405 **
10406 ** <pre>
10407 **   sqlite3_changegroup *pGrp;
10408 **   rc = sqlite3_changegroup_new(&pGrp);
10409 **   if( rc==SQLITE_OK ) rc = sqlite3changegroup_add(pGrp, nA, pA);
10410 **   if( rc==SQLITE_OK ) rc = sqlite3changegroup_add(pGrp, nB, pB);
10411 **   if( rc==SQLITE_OK ){
10412 **     rc = sqlite3changegroup_output(pGrp, pnOut, ppOut);
10413 **   }else{
10414 **     *ppOut = 0;
10415 **     *pnOut = 0;
10416 **   }
10417 ** </pre>
10418 **
10419 ** Refer to the sqlite3_changegroup documentation below for details.
10420 */
10421 SQLITE_API int sqlite3changeset_concat(
10422   int nA,                         /* Number of bytes in buffer pA */
10423   void *pA,                       /* Pointer to buffer containing changeset A */
10424   int nB,                         /* Number of bytes in buffer pB */
10425   void *pB,                       /* Pointer to buffer containing changeset B */
10426   int *pnOut,                     /* OUT: Number of bytes in output changeset */
10427   void **ppOut                    /* OUT: Buffer containing output changeset */
10428 );
10429 
10430 
10431 /*
10432 ** CAPI3REF: Changegroup Handle
10433 **
10434 ** A changegroup is an object used to combine two or more
10435 ** [changesets] or [patchsets]
10436 */
10437 typedef struct sqlite3_changegroup sqlite3_changegroup;
10438 
10439 /*
10440 ** CAPI3REF: Create A New Changegroup Object
10441 ** CONSTRUCTOR: sqlite3_changegroup
10442 **
10443 ** An sqlite3_changegroup object is used to combine two or more changesets
10444 ** (or patchsets) into a single changeset (or patchset). A single changegroup
10445 ** object may combine changesets or patchsets, but not both. The output is
10446 ** always in the same format as the input.
10447 **
10448 ** If successful, this function returns SQLITE_OK and populates (*pp) with
10449 ** a pointer to a new sqlite3_changegroup object before returning. The caller
10450 ** should eventually free the returned object using a call to
10451 ** sqlite3changegroup_delete(). If an error occurs, an SQLite error code
10452 ** (i.e. SQLITE_NOMEM) is returned and *pp is set to NULL.
10453 **
10454 ** The usual usage pattern for an sqlite3_changegroup object is as follows:
10455 **
10456 ** <ul>
10457 **   <li> It is created using a call to sqlite3changegroup_new().
10458 **
10459 **   <li> Zero or more changesets (or patchsets) are added to the object
10460 **        by calling sqlite3changegroup_add().
10461 **
10462 **   <li> The result of combining all input changesets together is obtained
10463 **        by the application via a call to sqlite3changegroup_output().
10464 **
10465 **   <li> The object is deleted using a call to sqlite3changegroup_delete().
10466 ** </ul>
10467 **
10468 ** Any number of calls to add() and output() may be made between the calls to
10469 ** new() and delete(), and in any order.
10470 **
10471 ** As well as the regular sqlite3changegroup_add() and
10472 ** sqlite3changegroup_output() functions, also available are the streaming
10473 ** versions sqlite3changegroup_add_strm() and sqlite3changegroup_output_strm().
10474 */
10475 SQLITE_API int sqlite3changegroup_new(sqlite3_changegroup **pp);
10476 
10477 /*
10478 ** CAPI3REF: Add A Changeset To A Changegroup
10479 ** METHOD: sqlite3_changegroup
10480 **
10481 ** Add all changes within the changeset (or patchset) in buffer pData (size
10482 ** nData bytes) to the changegroup.
10483 **
10484 ** If the buffer contains a patchset, then all prior calls to this function
10485 ** on the same changegroup object must also have specified patchsets. Or, if
10486 ** the buffer contains a changeset, so must have the earlier calls to this
10487 ** function. Otherwise, SQLITE_ERROR is returned and no changes are added
10488 ** to the changegroup.
10489 **
10490 ** Rows within the changeset and changegroup are identified by the values in
10491 ** their PRIMARY KEY columns. A change in the changeset is considered to
10492 ** apply to the same row as a change already present in the changegroup if
10493 ** the two rows have the same primary key.
10494 **
10495 ** Changes to rows that do not already appear in the changegroup are
10496 ** simply copied into it. Or, if both the new changeset and the changegroup
10497 ** contain changes that apply to a single row, the final contents of the
10498 ** changegroup depends on the type of each change, as follows:
10499 **
10500 ** <table border=1 style="margin-left:8ex;margin-right:8ex">
10501 **   <tr><th style="white-space:pre">Existing Change  </th>
10502 **       <th style="white-space:pre">New Change       </th>
10503 **       <th>Output Change
10504 **   <tr><td>INSERT <td>INSERT <td>
10505 **       The new change is ignored. This case does not occur if the new
10506 **       changeset was recorded immediately after the changesets already
10507 **       added to the changegroup.
10508 **   <tr><td>INSERT <td>UPDATE <td>
10509 **       The INSERT change remains in the changegroup. The values in the
10510 **       INSERT change are modified as if the row was inserted by the
10511 **       existing change and then updated according to the new change.
10512 **   <tr><td>INSERT <td>DELETE <td>
10513 **       The existing INSERT is removed from the changegroup. The DELETE is
10514 **       not added.
10515 **   <tr><td>UPDATE <td>INSERT <td>
10516 **       The new change is ignored. This case does not occur if the new
10517 **       changeset was recorded immediately after the changesets already
10518 **       added to the changegroup.
10519 **   <tr><td>UPDATE <td>UPDATE <td>
10520 **       The existing UPDATE remains within the changegroup. It is amended
10521 **       so that the accompanying values are as if the row was updated once
10522 **       by the existing change and then again by the new change.
10523 **   <tr><td>UPDATE <td>DELETE <td>
10524 **       The existing UPDATE is replaced by the new DELETE within the
10525 **       changegroup.
10526 **   <tr><td>DELETE <td>INSERT <td>
10527 **       If one or more of the column values in the row inserted by the
10528 **       new change differ from those in the row deleted by the existing
10529 **       change, the existing DELETE is replaced by an UPDATE within the
10530 **       changegroup. Otherwise, if the inserted row is exactly the same
10531 **       as the deleted row, the existing DELETE is simply discarded.
10532 **   <tr><td>DELETE <td>UPDATE <td>
10533 **       The new change is ignored. This case does not occur if the new
10534 **       changeset was recorded immediately after the changesets already
10535 **       added to the changegroup.
10536 **   <tr><td>DELETE <td>DELETE <td>
10537 **       The new change is ignored. This case does not occur if the new
10538 **       changeset was recorded immediately after the changesets already
10539 **       added to the changegroup.
10540 ** </table>
10541 **
10542 ** If the new changeset contains changes to a table that is already present
10543 ** in the changegroup, then the number of columns and the position of the
10544 ** primary key columns for the table must be consistent. If this is not the
10545 ** case, this function fails with SQLITE_SCHEMA. If the input changeset
10546 ** appears to be corrupt and the corruption is detected, SQLITE_CORRUPT is
10547 ** returned. Or, if an out-of-memory condition occurs during processing, this
10548 ** function returns SQLITE_NOMEM. In all cases, if an error occurs the
10549 ** final contents of the changegroup is undefined.
10550 **
10551 ** If no error occurs, SQLITE_OK is returned.
10552 */
10553 SQLITE_API int sqlite3changegroup_add(sqlite3_changegroup*, int nData, void *pData);
10554 
10555 /*
10556 ** CAPI3REF: Obtain A Composite Changeset From A Changegroup
10557 ** METHOD: sqlite3_changegroup
10558 **
10559 ** Obtain a buffer containing a changeset (or patchset) representing the
10560 ** current contents of the changegroup. If the inputs to the changegroup
10561 ** were themselves changesets, the output is a changeset. Or, if the
10562 ** inputs were patchsets, the output is also a patchset.
10563 **
10564 ** As with the output of the sqlite3session_changeset() and
10565 ** sqlite3session_patchset() functions, all changes related to a single
10566 ** table are grouped together in the output of this function. Tables appear
10567 ** in the same order as for the very first changeset added to the changegroup.
10568 ** If the second or subsequent changesets added to the changegroup contain
10569 ** changes for tables that do not appear in the first changeset, they are
10570 ** appended onto the end of the output changeset, again in the order in
10571 ** which they are first encountered.
10572 **
10573 ** If an error occurs, an SQLite error code is returned and the output
10574 ** variables (*pnData) and (*ppData) are set to 0. Otherwise, SQLITE_OK
10575 ** is returned and the output variables are set to the size of and a
10576 ** pointer to the output buffer, respectively. In this case it is the
10577 ** responsibility of the caller to eventually free the buffer using a
10578 ** call to sqlite3_free().
10579 */
10580 SQLITE_API int sqlite3changegroup_output(
10581   sqlite3_changegroup*,
10582   int *pnData,                    /* OUT: Size of output buffer in bytes */
10583   void **ppData                   /* OUT: Pointer to output buffer */
10584 );
10585 
10586 /*
10587 ** CAPI3REF: Delete A Changegroup Object
10588 ** DESTRUCTOR: sqlite3_changegroup
10589 */
10590 SQLITE_API void sqlite3changegroup_delete(sqlite3_changegroup*);
10591 
10592 /*
10593 ** CAPI3REF: Apply A Changeset To A Database
10594 **
10595 ** Apply a changeset or patchset to a database. These functions attempt to
10596 ** update the "main" database attached to handle db with the changes found in
10597 ** the changeset passed via the second and third arguments.
10598 **
10599 ** The fourth argument (xFilter) passed to these functions is the "filter
10600 ** callback". If it is not NULL, then for each table affected by at least one
10601 ** change in the changeset, the filter callback is invoked with
10602 ** the table name as the second argument, and a copy of the context pointer
10603 ** passed as the sixth argument as the first. If the "filter callback"
10604 ** returns zero, then no attempt is made to apply any changes to the table.
10605 ** Otherwise, if the return value is non-zero or the xFilter argument to
10606 ** is NULL, all changes related to the table are attempted.
10607 **
10608 ** For each table that is not excluded by the filter callback, this function
10609 ** tests that the target database contains a compatible table. A table is
10610 ** considered compatible if all of the following are true:
10611 **
10612 ** <ul>
10613 **   <li> The table has the same name as the name recorded in the
10614 **        changeset, and
10615 **   <li> The table has at least as many columns as recorded in the
10616 **        changeset, and
10617 **   <li> The table has primary key columns in the same position as
10618 **        recorded in the changeset.
10619 ** </ul>
10620 **
10621 ** If there is no compatible table, it is not an error, but none of the
10622 ** changes associated with the table are applied. A warning message is issued
10623 ** via the sqlite3_log() mechanism with the error code SQLITE_SCHEMA. At most
10624 ** one such warning is issued for each table in the changeset.
10625 **
10626 ** For each change for which there is a compatible table, an attempt is made
10627 ** to modify the table contents according to the UPDATE, INSERT or DELETE
10628 ** change. If a change cannot be applied cleanly, the conflict handler
10629 ** function passed as the fifth argument to sqlite3changeset_apply() may be
10630 ** invoked. A description of exactly when the conflict handler is invoked for
10631 ** each type of change is below.
10632 **
10633 ** Unlike the xFilter argument, xConflict may not be passed NULL. The results
10634 ** of passing anything other than a valid function pointer as the xConflict
10635 ** argument are undefined.
10636 **
10637 ** Each time the conflict handler function is invoked, it must return one
10638 ** of [SQLITE_CHANGESET_OMIT], [SQLITE_CHANGESET_ABORT] or
10639 ** [SQLITE_CHANGESET_REPLACE]. SQLITE_CHANGESET_REPLACE may only be returned
10640 ** if the second argument passed to the conflict handler is either
10641 ** SQLITE_CHANGESET_DATA or SQLITE_CHANGESET_CONFLICT. If the conflict-handler
10642 ** returns an illegal value, any changes already made are rolled back and
10643 ** the call to sqlite3changeset_apply() returns SQLITE_MISUSE. Different
10644 ** actions are taken by sqlite3changeset_apply() depending on the value
10645 ** returned by each invocation of the conflict-handler function. Refer to
10646 ** the documentation for the three
10647 ** [SQLITE_CHANGESET_OMIT|available return values] for details.
10648 **
10649 ** <dl>
10650 ** <dt>DELETE Changes<dd>
10651 **   For each DELETE change, the function checks if the target database
10652 **   contains a row with the same primary key value (or values) as the
10653 **   original row values stored in the changeset. If it does, and the values
10654 **   stored in all non-primary key columns also match the values stored in
10655 **   the changeset the row is deleted from the target database.
10656 **
10657 **   If a row with matching primary key values is found, but one or more of
10658 **   the non-primary key fields contains a value different from the original
10659 **   row value stored in the changeset, the conflict-handler function is
10660 **   invoked with [SQLITE_CHANGESET_DATA] as the second argument. If the
10661 **   database table has more columns than are recorded in the changeset,
10662 **   only the values of those non-primary key fields are compared against
10663 **   the current database contents - any trailing database table columns
10664 **   are ignored.
10665 **
10666 **   If no row with matching primary key values is found in the database,
10667 **   the conflict-handler function is invoked with [SQLITE_CHANGESET_NOTFOUND]
10668 **   passed as the second argument.
10669 **
10670 **   If the DELETE operation is attempted, but SQLite returns SQLITE_CONSTRAINT
10671 **   (which can only happen if a foreign key constraint is violated), the
10672 **   conflict-handler function is invoked with [SQLITE_CHANGESET_CONSTRAINT]
10673 **   passed as the second argument. This includes the case where the DELETE
10674 **   operation is attempted because an earlier call to the conflict handler
10675 **   function returned [SQLITE_CHANGESET_REPLACE].
10676 **
10677 ** <dt>INSERT Changes<dd>
10678 **   For each INSERT change, an attempt is made to insert the new row into
10679 **   the database. If the changeset row contains fewer fields than the
10680 **   database table, the trailing fields are populated with their default
10681 **   values.
10682 **
10683 **   If the attempt to insert the row fails because the database already
10684 **   contains a row with the same primary key values, the conflict handler
10685 **   function is invoked with the second argument set to
10686 **   [SQLITE_CHANGESET_CONFLICT].
10687 **
10688 **   If the attempt to insert the row fails because of some other constraint
10689 **   violation (e.g. NOT NULL or UNIQUE), the conflict handler function is
10690 **   invoked with the second argument set to [SQLITE_CHANGESET_CONSTRAINT].
10691 **   This includes the case where the INSERT operation is re-attempted because
10692 **   an earlier call to the conflict handler function returned
10693 **   [SQLITE_CHANGESET_REPLACE].
10694 **
10695 ** <dt>UPDATE Changes<dd>
10696 **   For each UPDATE change, the function checks if the target database
10697 **   contains a row with the same primary key value (or values) as the
10698 **   original row values stored in the changeset. If it does, and the values
10699 **   stored in all modified non-primary key columns also match the values
10700 **   stored in the changeset the row is updated within the target database.
10701 **
10702 **   If a row with matching primary key values is found, but one or more of
10703 **   the modified non-primary key fields contains a value different from an
10704 **   original row value stored in the changeset, the conflict-handler function
10705 **   is invoked with [SQLITE_CHANGESET_DATA] as the second argument. Since
10706 **   UPDATE changes only contain values for non-primary key fields that are
10707 **   to be modified, only those fields need to match the original values to
10708 **   avoid the SQLITE_CHANGESET_DATA conflict-handler callback.
10709 **
10710 **   If no row with matching primary key values is found in the database,
10711 **   the conflict-handler function is invoked with [SQLITE_CHANGESET_NOTFOUND]
10712 **   passed as the second argument.
10713 **
10714 **   If the UPDATE operation is attempted, but SQLite returns
10715 **   SQLITE_CONSTRAINT, the conflict-handler function is invoked with
10716 **   [SQLITE_CHANGESET_CONSTRAINT] passed as the second argument.
10717 **   This includes the case where the UPDATE operation is attempted after
10718 **   an earlier call to the conflict handler function returned
10719 **   [SQLITE_CHANGESET_REPLACE].
10720 ** </dl>
10721 **
10722 ** It is safe to execute SQL statements, including those that write to the
10723 ** table that the callback related to, from within the xConflict callback.
10724 ** This can be used to further customize the applications conflict
10725 ** resolution strategy.
10726 **
10727 ** All changes made by these functions are enclosed in a savepoint transaction.
10728 ** If any other error (aside from a constraint failure when attempting to
10729 ** write to the target database) occurs, then the savepoint transaction is
10730 ** rolled back, restoring the target database to its original state, and an
10731 ** SQLite error code returned.
10732 **
10733 ** If the output parameters (ppRebase) and (pnRebase) are non-NULL and
10734 ** the input is a changeset (not a patchset), then sqlite3changeset_apply_v2()
10735 ** may set (*ppRebase) to point to a "rebase" that may be used with the
10736 ** sqlite3_rebaser APIs buffer before returning. In this case (*pnRebase)
10737 ** is set to the size of the buffer in bytes. It is the responsibility of the
10738 ** caller to eventually free any such buffer using sqlite3_free(). The buffer
10739 ** is only allocated and populated if one or more conflicts were encountered
10740 ** while applying the patchset. See comments surrounding the sqlite3_rebaser
10741 ** APIs for further details.
10742 **
10743 ** The behavior of sqlite3changeset_apply_v2() and its streaming equivalent
10744 ** may be modified by passing a combination of
10745 ** [SQLITE_CHANGESETAPPLY_NOSAVEPOINT | supported flags] as the 9th parameter.
10746 **
10747 ** Note that the sqlite3changeset_apply_v2() API is still <b>experimental</b>
10748 ** and therefore subject to change.
10749 */
10750 SQLITE_API int sqlite3changeset_apply(
10751   sqlite3 *db,                    /* Apply change to "main" db of this handle */
10752   int nChangeset,                 /* Size of changeset in bytes */
10753   void *pChangeset,               /* Changeset blob */
10754   int(*xFilter)(
10755     void *pCtx,                   /* Copy of sixth arg to _apply() */
10756     const char *zTab              /* Table name */
10757   ),
10758   int(*xConflict)(
10759     void *pCtx,                   /* Copy of sixth arg to _apply() */
10760     int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
10761     sqlite3_changeset_iter *p     /* Handle describing change and conflict */
10762   ),
10763   void *pCtx                      /* First argument passed to xConflict */
10764 );
10765 SQLITE_API int sqlite3changeset_apply_v2(
10766   sqlite3 *db,                    /* Apply change to "main" db of this handle */
10767   int nChangeset,                 /* Size of changeset in bytes */
10768   void *pChangeset,               /* Changeset blob */
10769   int(*xFilter)(
10770     void *pCtx,                   /* Copy of sixth arg to _apply() */
10771     const char *zTab              /* Table name */
10772   ),
10773   int(*xConflict)(
10774     void *pCtx,                   /* Copy of sixth arg to _apply() */
10775     int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
10776     sqlite3_changeset_iter *p     /* Handle describing change and conflict */
10777   ),
10778   void *pCtx,                     /* First argument passed to xConflict */
10779   void **ppRebase, int *pnRebase, /* OUT: Rebase data */
10780   int flags                       /* SESSION_CHANGESETAPPLY_* flags */
10781 );
10782 
10783 /*
10784 ** CAPI3REF: Flags for sqlite3changeset_apply_v2
10785 **
10786 ** The following flags may passed via the 9th parameter to
10787 ** [sqlite3changeset_apply_v2] and [sqlite3changeset_apply_v2_strm]:
10788 **
10789 ** <dl>
10790 ** <dt>SQLITE_CHANGESETAPPLY_NOSAVEPOINT <dd>
10791 **   Usually, the sessions module encloses all operations performed by
10792 **   a single call to apply_v2() or apply_v2_strm() in a [SAVEPOINT]. The
10793 **   SAVEPOINT is committed if the changeset or patchset is successfully
10794 **   applied, or rolled back if an error occurs. Specifying this flag
10795 **   causes the sessions module to omit this savepoint. In this case, if the
10796 **   caller has an open transaction or savepoint when apply_v2() is called,
10797 **   it may revert the partially applied changeset by rolling it back.
10798 **
10799 ** <dt>SQLITE_CHANGESETAPPLY_INVERT <dd>
10800 **   Invert the changeset before applying it. This is equivalent to inverting
10801 **   a changeset using sqlite3changeset_invert() before applying it. It is
10802 **   an error to specify this flag with a patchset.
10803 */
10804 #define SQLITE_CHANGESETAPPLY_NOSAVEPOINT   0x0001
10805 #define SQLITE_CHANGESETAPPLY_INVERT        0x0002
10806 
10807 /*
10808 ** CAPI3REF: Constants Passed To The Conflict Handler
10809 **
10810 ** Values that may be passed as the second argument to a conflict-handler.
10811 **
10812 ** <dl>
10813 ** <dt>SQLITE_CHANGESET_DATA<dd>
10814 **   The conflict handler is invoked with CHANGESET_DATA as the second argument
10815 **   when processing a DELETE or UPDATE change if a row with the required
10816 **   PRIMARY KEY fields is present in the database, but one or more other
10817 **   (non primary-key) fields modified by the update do not contain the
10818 **   expected "before" values.
10819 **
10820 **   The conflicting row, in this case, is the database row with the matching
10821 **   primary key.
10822 **
10823 ** <dt>SQLITE_CHANGESET_NOTFOUND<dd>
10824 **   The conflict handler is invoked with CHANGESET_NOTFOUND as the second
10825 **   argument when processing a DELETE or UPDATE change if a row with the
10826 **   required PRIMARY KEY fields is not present in the database.
10827 **
10828 **   There is no conflicting row in this case. The results of invoking the
10829 **   sqlite3changeset_conflict() API are undefined.
10830 **
10831 ** <dt>SQLITE_CHANGESET_CONFLICT<dd>
10832 **   CHANGESET_CONFLICT is passed as the second argument to the conflict
10833 **   handler while processing an INSERT change if the operation would result
10834 **   in duplicate primary key values.
10835 **
10836 **   The conflicting row in this case is the database row with the matching
10837 **   primary key.
10838 **
10839 ** <dt>SQLITE_CHANGESET_FOREIGN_KEY<dd>
10840 **   If foreign key handling is enabled, and applying a changeset leaves the
10841 **   database in a state containing foreign key violations, the conflict
10842 **   handler is invoked with CHANGESET_FOREIGN_KEY as the second argument
10843 **   exactly once before the changeset is committed. If the conflict handler
10844 **   returns CHANGESET_OMIT, the changes, including those that caused the
10845 **   foreign key constraint violation, are committed. Or, if it returns
10846 **   CHANGESET_ABORT, the changeset is rolled back.
10847 **
10848 **   No current or conflicting row information is provided. The only function
10849 **   it is possible to call on the supplied sqlite3_changeset_iter handle
10850 **   is sqlite3changeset_fk_conflicts().
10851 **
10852 ** <dt>SQLITE_CHANGESET_CONSTRAINT<dd>
10853 **   If any other constraint violation occurs while applying a change (i.e.
10854 **   a UNIQUE, CHECK or NOT NULL constraint), the conflict handler is
10855 **   invoked with CHANGESET_CONSTRAINT as the second argument.
10856 **
10857 **   There is no conflicting row in this case. The results of invoking the
10858 **   sqlite3changeset_conflict() API are undefined.
10859 **
10860 ** </dl>
10861 */
10862 #define SQLITE_CHANGESET_DATA        1
10863 #define SQLITE_CHANGESET_NOTFOUND    2
10864 #define SQLITE_CHANGESET_CONFLICT    3
10865 #define SQLITE_CHANGESET_CONSTRAINT  4
10866 #define SQLITE_CHANGESET_FOREIGN_KEY 5
10867 
10868 /*
10869 ** CAPI3REF: Constants Returned By The Conflict Handler
10870 **
10871 ** A conflict handler callback must return one of the following three values.
10872 **
10873 ** <dl>
10874 ** <dt>SQLITE_CHANGESET_OMIT<dd>
10875 **   If a conflict handler returns this value no special action is taken. The
10876 **   change that caused the conflict is not applied. The session module
10877 **   continues to the next change in the changeset.
10878 **
10879 ** <dt>SQLITE_CHANGESET_REPLACE<dd>
10880 **   This value may only be returned if the second argument to the conflict
10881 **   handler was SQLITE_CHANGESET_DATA or SQLITE_CHANGESET_CONFLICT. If this
10882 **   is not the case, any changes applied so far are rolled back and the
10883 **   call to sqlite3changeset_apply() returns SQLITE_MISUSE.
10884 **
10885 **   If CHANGESET_REPLACE is returned by an SQLITE_CHANGESET_DATA conflict
10886 **   handler, then the conflicting row is either updated or deleted, depending
10887 **   on the type of change.
10888 **
10889 **   If CHANGESET_REPLACE is returned by an SQLITE_CHANGESET_CONFLICT conflict
10890 **   handler, then the conflicting row is removed from the database and a
10891 **   second attempt to apply the change is made. If this second attempt fails,
10892 **   the original row is restored to the database before continuing.
10893 **
10894 ** <dt>SQLITE_CHANGESET_ABORT<dd>
10895 **   If this value is returned, any changes applied so far are rolled back
10896 **   and the call to sqlite3changeset_apply() returns SQLITE_ABORT.
10897 ** </dl>
10898 */
10899 #define SQLITE_CHANGESET_OMIT       0
10900 #define SQLITE_CHANGESET_REPLACE    1
10901 #define SQLITE_CHANGESET_ABORT      2
10902 
10903 /*
10904 ** CAPI3REF: Rebasing changesets
10905 ** EXPERIMENTAL
10906 **
10907 ** Suppose there is a site hosting a database in state S0. And that
10908 ** modifications are made that move that database to state S1 and a
10909 ** changeset recorded (the "local" changeset). Then, a changeset based
10910 ** on S0 is received from another site (the "remote" changeset) and
10911 ** applied to the database. The database is then in state
10912 ** (S1+"remote"), where the exact state depends on any conflict
10913 ** resolution decisions (OMIT or REPLACE) made while applying "remote".
10914 ** Rebasing a changeset is to update it to take those conflict
10915 ** resolution decisions into account, so that the same conflicts
10916 ** do not have to be resolved elsewhere in the network.
10917 **
10918 ** For example, if both the local and remote changesets contain an
10919 ** INSERT of the same key on "CREATE TABLE t1(a PRIMARY KEY, b)":
10920 **
10921 **   local:  INSERT INTO t1 VALUES(1, 'v1');
10922 **   remote: INSERT INTO t1 VALUES(1, 'v2');
10923 **
10924 ** and the conflict resolution is REPLACE, then the INSERT change is
10925 ** removed from the local changeset (it was overridden). Or, if the
10926 ** conflict resolution was "OMIT", then the local changeset is modified
10927 ** to instead contain:
10928 **
10929 **           UPDATE t1 SET b = 'v2' WHERE a=1;
10930 **
10931 ** Changes within the local changeset are rebased as follows:
10932 **
10933 ** <dl>
10934 ** <dt>Local INSERT<dd>
10935 **   This may only conflict with a remote INSERT. If the conflict
10936 **   resolution was OMIT, then add an UPDATE change to the rebased
10937 **   changeset. Or, if the conflict resolution was REPLACE, add
10938 **   nothing to the rebased changeset.
10939 **
10940 ** <dt>Local DELETE<dd>
10941 **   This may conflict with a remote UPDATE or DELETE. In both cases the
10942 **   only possible resolution is OMIT. If the remote operation was a
10943 **   DELETE, then add no change to the rebased changeset. If the remote
10944 **   operation was an UPDATE, then the old.* fields of change are updated
10945 **   to reflect the new.* values in the UPDATE.
10946 **
10947 ** <dt>Local UPDATE<dd>
10948 **   This may conflict with a remote UPDATE or DELETE. If it conflicts
10949 **   with a DELETE, and the conflict resolution was OMIT, then the update
10950 **   is changed into an INSERT. Any undefined values in the new.* record
10951 **   from the update change are filled in using the old.* values from
10952 **   the conflicting DELETE. Or, if the conflict resolution was REPLACE,
10953 **   the UPDATE change is simply omitted from the rebased changeset.
10954 **
10955 **   If conflict is with a remote UPDATE and the resolution is OMIT, then
10956 **   the old.* values are rebased using the new.* values in the remote
10957 **   change. Or, if the resolution is REPLACE, then the change is copied
10958 **   into the rebased changeset with updates to columns also updated by
10959 **   the conflicting remote UPDATE removed. If this means no columns would
10960 **   be updated, the change is omitted.
10961 ** </dl>
10962 **
10963 ** A local change may be rebased against multiple remote changes
10964 ** simultaneously. If a single key is modified by multiple remote
10965 ** changesets, they are combined as follows before the local changeset
10966 ** is rebased:
10967 **
10968 ** <ul>
10969 **    <li> If there has been one or more REPLACE resolutions on a
10970 **         key, it is rebased according to a REPLACE.
10971 **
10972 **    <li> If there have been no REPLACE resolutions on a key, then
10973 **         the local changeset is rebased according to the most recent
10974 **         of the OMIT resolutions.
10975 ** </ul>
10976 **
10977 ** Note that conflict resolutions from multiple remote changesets are
10978 ** combined on a per-field basis, not per-row. This means that in the
10979 ** case of multiple remote UPDATE operations, some fields of a single
10980 ** local change may be rebased for REPLACE while others are rebased for
10981 ** OMIT.
10982 **
10983 ** In order to rebase a local changeset, the remote changeset must first
10984 ** be applied to the local database using sqlite3changeset_apply_v2() and
10985 ** the buffer of rebase information captured. Then:
10986 **
10987 ** <ol>
10988 **   <li> An sqlite3_rebaser object is created by calling
10989 **        sqlite3rebaser_create().
10990 **   <li> The new object is configured with the rebase buffer obtained from
10991 **        sqlite3changeset_apply_v2() by calling sqlite3rebaser_configure().
10992 **        If the local changeset is to be rebased against multiple remote
10993 **        changesets, then sqlite3rebaser_configure() should be called
10994 **        multiple times, in the same order that the multiple
10995 **        sqlite3changeset_apply_v2() calls were made.
10996 **   <li> Each local changeset is rebased by calling sqlite3rebaser_rebase().
10997 **   <li> The sqlite3_rebaser object is deleted by calling
10998 **        sqlite3rebaser_delete().
10999 ** </ol>
11000 */
11001 typedef struct sqlite3_rebaser sqlite3_rebaser;
11002 
11003 /*
11004 ** CAPI3REF: Create a changeset rebaser object.
11005 ** EXPERIMENTAL
11006 **
11007 ** Allocate a new changeset rebaser object. If successful, set (*ppNew) to
11008 ** point to the new object and return SQLITE_OK. Otherwise, if an error
11009 ** occurs, return an SQLite error code (e.g. SQLITE_NOMEM) and set (*ppNew)
11010 ** to NULL.
11011 */
11012 SQLITE_API int sqlite3rebaser_create(sqlite3_rebaser **ppNew);
11013 
11014 /*
11015 ** CAPI3REF: Configure a changeset rebaser object.
11016 ** EXPERIMENTAL
11017 **
11018 ** Configure the changeset rebaser object to rebase changesets according
11019 ** to the conflict resolutions described by buffer pRebase (size nRebase
11020 ** bytes), which must have been obtained from a previous call to
11021 ** sqlite3changeset_apply_v2().
11022 */
11023 SQLITE_API int sqlite3rebaser_configure(
11024   sqlite3_rebaser*,
11025   int nRebase, const void *pRebase
11026 );
11027 
11028 /*
11029 ** CAPI3REF: Rebase a changeset
11030 ** EXPERIMENTAL
11031 **
11032 ** Argument pIn must point to a buffer containing a changeset nIn bytes
11033 ** in size. This function allocates and populates a buffer with a copy
11034 ** of the changeset rebased rebased according to the configuration of the
11035 ** rebaser object passed as the first argument. If successful, (*ppOut)
11036 ** is set to point to the new buffer containing the rebased changeset and
11037 ** (*pnOut) to its size in bytes and SQLITE_OK returned. It is the
11038 ** responsibility of the caller to eventually free the new buffer using
11039 ** sqlite3_free(). Otherwise, if an error occurs, (*ppOut) and (*pnOut)
11040 ** are set to zero and an SQLite error code returned.
11041 */
11042 SQLITE_API int sqlite3rebaser_rebase(
11043   sqlite3_rebaser*,
11044   int nIn, const void *pIn,
11045   int *pnOut, void **ppOut
11046 );
11047 
11048 /*
11049 ** CAPI3REF: Delete a changeset rebaser object.
11050 ** EXPERIMENTAL
11051 **
11052 ** Delete the changeset rebaser object and all associated resources. There
11053 ** should be one call to this function for each successful invocation
11054 ** of sqlite3rebaser_create().
11055 */
11056 SQLITE_API void sqlite3rebaser_delete(sqlite3_rebaser *p);
11057 
11058 /*
11059 ** CAPI3REF: Streaming Versions of API functions.
11060 **
11061 ** The six streaming API xxx_strm() functions serve similar purposes to the
11062 ** corresponding non-streaming API functions:
11063 **
11064 ** <table border=1 style="margin-left:8ex;margin-right:8ex">
11065 **   <tr><th>Streaming function<th>Non-streaming equivalent</th>
11066 **   <tr><td>sqlite3changeset_apply_strm<td>[sqlite3changeset_apply]
11067 **   <tr><td>sqlite3changeset_apply_strm_v2<td>[sqlite3changeset_apply_v2]
11068 **   <tr><td>sqlite3changeset_concat_strm<td>[sqlite3changeset_concat]
11069 **   <tr><td>sqlite3changeset_invert_strm<td>[sqlite3changeset_invert]
11070 **   <tr><td>sqlite3changeset_start_strm<td>[sqlite3changeset_start]
11071 **   <tr><td>sqlite3session_changeset_strm<td>[sqlite3session_changeset]
11072 **   <tr><td>sqlite3session_patchset_strm<td>[sqlite3session_patchset]
11073 ** </table>
11074 **
11075 ** Non-streaming functions that accept changesets (or patchsets) as input
11076 ** require that the entire changeset be stored in a single buffer in memory.
11077 ** Similarly, those that return a changeset or patchset do so by returning
11078 ** a pointer to a single large buffer allocated using sqlite3_malloc().
11079 ** Normally this is convenient. However, if an application running in a
11080 ** low-memory environment is required to handle very large changesets, the
11081 ** large contiguous memory allocations required can become onerous.
11082 **
11083 ** In order to avoid this problem, instead of a single large buffer, input
11084 ** is passed to a streaming API functions by way of a callback function that
11085 ** the sessions module invokes to incrementally request input data as it is
11086 ** required. In all cases, a pair of API function parameters such as
11087 **
11088 **  <pre>
11089 **  &nbsp;     int nChangeset,
11090 **  &nbsp;     void *pChangeset,
11091 **  </pre>
11092 **
11093 ** Is replaced by:
11094 **
11095 **  <pre>
11096 **  &nbsp;     int (*xInput)(void *pIn, void *pData, int *pnData),
11097 **  &nbsp;     void *pIn,
11098 **  </pre>
11099 **
11100 ** Each time the xInput callback is invoked by the sessions module, the first
11101 ** argument passed is a copy of the supplied pIn context pointer. The second
11102 ** argument, pData, points to a buffer (*pnData) bytes in size. Assuming no
11103 ** error occurs the xInput method should copy up to (*pnData) bytes of data
11104 ** into the buffer and set (*pnData) to the actual number of bytes copied
11105 ** before returning SQLITE_OK. If the input is completely exhausted, (*pnData)
11106 ** should be set to zero to indicate this. Or, if an error occurs, an SQLite
11107 ** error code should be returned. In all cases, if an xInput callback returns
11108 ** an error, all processing is abandoned and the streaming API function
11109 ** returns a copy of the error code to the caller.
11110 **
11111 ** In the case of sqlite3changeset_start_strm(), the xInput callback may be
11112 ** invoked by the sessions module at any point during the lifetime of the
11113 ** iterator. If such an xInput callback returns an error, the iterator enters
11114 ** an error state, whereby all subsequent calls to iterator functions
11115 ** immediately fail with the same error code as returned by xInput.
11116 **
11117 ** Similarly, streaming API functions that return changesets (or patchsets)
11118 ** return them in chunks by way of a callback function instead of via a
11119 ** pointer to a single large buffer. In this case, a pair of parameters such
11120 ** as:
11121 **
11122 **  <pre>
11123 **  &nbsp;     int *pnChangeset,
11124 **  &nbsp;     void **ppChangeset,
11125 **  </pre>
11126 **
11127 ** Is replaced by:
11128 **
11129 **  <pre>
11130 **  &nbsp;     int (*xOutput)(void *pOut, const void *pData, int nData),
11131 **  &nbsp;     void *pOut
11132 **  </pre>
11133 **
11134 ** The xOutput callback is invoked zero or more times to return data to
11135 ** the application. The first parameter passed to each call is a copy of the
11136 ** pOut pointer supplied by the application. The second parameter, pData,
11137 ** points to a buffer nData bytes in size containing the chunk of output
11138 ** data being returned. If the xOutput callback successfully processes the
11139 ** supplied data, it should return SQLITE_OK to indicate success. Otherwise,
11140 ** it should return some other SQLite error code. In this case processing
11141 ** is immediately abandoned and the streaming API function returns a copy
11142 ** of the xOutput error code to the application.
11143 **
11144 ** The sessions module never invokes an xOutput callback with the third
11145 ** parameter set to a value less than or equal to zero. Other than this,
11146 ** no guarantees are made as to the size of the chunks of data returned.
11147 */
11148 SQLITE_API int sqlite3changeset_apply_strm(
11149   sqlite3 *db,                    /* Apply change to "main" db of this handle */
11150   int (*xInput)(void *pIn, void *pData, int *pnData), /* Input function */
11151   void *pIn,                                          /* First arg for xInput */
11152   int(*xFilter)(
11153     void *pCtx,                   /* Copy of sixth arg to _apply() */
11154     const char *zTab              /* Table name */
11155   ),
11156   int(*xConflict)(
11157     void *pCtx,                   /* Copy of sixth arg to _apply() */
11158     int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
11159     sqlite3_changeset_iter *p     /* Handle describing change and conflict */
11160   ),
11161   void *pCtx                      /* First argument passed to xConflict */
11162 );
11163 SQLITE_API int sqlite3changeset_apply_v2_strm(
11164   sqlite3 *db,                    /* Apply change to "main" db of this handle */
11165   int (*xInput)(void *pIn, void *pData, int *pnData), /* Input function */
11166   void *pIn,                                          /* First arg for xInput */
11167   int(*xFilter)(
11168     void *pCtx,                   /* Copy of sixth arg to _apply() */
11169     const char *zTab              /* Table name */
11170   ),
11171   int(*xConflict)(
11172     void *pCtx,                   /* Copy of sixth arg to _apply() */
11173     int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
11174     sqlite3_changeset_iter *p     /* Handle describing change and conflict */
11175   ),
11176   void *pCtx,                     /* First argument passed to xConflict */
11177   void **ppRebase, int *pnRebase,
11178   int flags
11179 );
11180 SQLITE_API int sqlite3changeset_concat_strm(
11181   int (*xInputA)(void *pIn, void *pData, int *pnData),
11182   void *pInA,
11183   int (*xInputB)(void *pIn, void *pData, int *pnData),
11184   void *pInB,
11185   int (*xOutput)(void *pOut, const void *pData, int nData),
11186   void *pOut
11187 );
11188 SQLITE_API int sqlite3changeset_invert_strm(
11189   int (*xInput)(void *pIn, void *pData, int *pnData),
11190   void *pIn,
11191   int (*xOutput)(void *pOut, const void *pData, int nData),
11192   void *pOut
11193 );
11194 SQLITE_API int sqlite3changeset_start_strm(
11195   sqlite3_changeset_iter **pp,
11196   int (*xInput)(void *pIn, void *pData, int *pnData),
11197   void *pIn
11198 );
11199 SQLITE_API int sqlite3changeset_start_v2_strm(
11200   sqlite3_changeset_iter **pp,
11201   int (*xInput)(void *pIn, void *pData, int *pnData),
11202   void *pIn,
11203   int flags
11204 );
11205 SQLITE_API int sqlite3session_changeset_strm(
11206   sqlite3_session *pSession,
11207   int (*xOutput)(void *pOut, const void *pData, int nData),
11208   void *pOut
11209 );
11210 SQLITE_API int sqlite3session_patchset_strm(
11211   sqlite3_session *pSession,
11212   int (*xOutput)(void *pOut, const void *pData, int nData),
11213   void *pOut
11214 );
11215 SQLITE_API int sqlite3changegroup_add_strm(sqlite3_changegroup*,
11216     int (*xInput)(void *pIn, void *pData, int *pnData),
11217     void *pIn
11218 );
11219 SQLITE_API int sqlite3changegroup_output_strm(sqlite3_changegroup*,
11220     int (*xOutput)(void *pOut, const void *pData, int nData),
11221     void *pOut
11222 );
11223 SQLITE_API int sqlite3rebaser_rebase_strm(
11224   sqlite3_rebaser *pRebaser,
11225   int (*xInput)(void *pIn, void *pData, int *pnData),
11226   void *pIn,
11227   int (*xOutput)(void *pOut, const void *pData, int nData),
11228   void *pOut
11229 );
11230 
11231 /*
11232 ** CAPI3REF: Configure global parameters
11233 **
11234 ** The sqlite3session_config() interface is used to make global configuration
11235 ** changes to the sessions module in order to tune it to the specific needs
11236 ** of the application.
11237 **
11238 ** The sqlite3session_config() interface is not threadsafe. If it is invoked
11239 ** while any other thread is inside any other sessions method then the
11240 ** results are undefined. Furthermore, if it is invoked after any sessions
11241 ** related objects have been created, the results are also undefined.
11242 **
11243 ** The first argument to the sqlite3session_config() function must be one
11244 ** of the SQLITE_SESSION_CONFIG_XXX constants defined below. The
11245 ** interpretation of the (void*) value passed as the second parameter and
11246 ** the effect of calling this function depends on the value of the first
11247 ** parameter.
11248 **
11249 ** <dl>
11250 ** <dt>SQLITE_SESSION_CONFIG_STRMSIZE<dd>
11251 **    By default, the sessions module streaming interfaces attempt to input
11252 **    and output data in approximately 1 KiB chunks. This operand may be used
11253 **    to set and query the value of this configuration setting. The pointer
11254 **    passed as the second argument must point to a value of type (int).
11255 **    If this value is greater than 0, it is used as the new streaming data
11256 **    chunk size for both input and output. Before returning, the (int) value
11257 **    pointed to by pArg is set to the final value of the streaming interface
11258 **    chunk size.
11259 ** </dl>
11260 **
11261 ** This function returns SQLITE_OK if successful, or an SQLite error code
11262 ** otherwise.
11263 */
11264 SQLITE_API int sqlite3session_config(int op, void *pArg);
11265 
11266 /*
11267 ** CAPI3REF: Values for sqlite3session_config().
11268 */
11269 #define SQLITE_SESSION_CONFIG_STRMSIZE 1
11270 
11271 /*
11272 ** Make sure we can call this stuff from C++.
11273 */
11274 #ifdef __cplusplus
11275 }
11276 #endif
11277 
11278 #endif  /* !defined(__SQLITESESSION_H_) && defined(SQLITE_ENABLE_SESSION) */
11279 
11280 /******** End of sqlite3session.h *********/
11281 /******** Begin file fts5.h *********/
11282 /*
11283 ** 2014 May 31
11284 **
11285 ** The author disclaims copyright to this source code.  In place of
11286 ** a legal notice, here is a blessing:
11287 **
11288 **    May you do good and not evil.
11289 **    May you find forgiveness for yourself and forgive others.
11290 **    May you share freely, never taking more than you give.
11291 **
11292 ******************************************************************************
11293 **
11294 ** Interfaces to extend FTS5. Using the interfaces defined in this file,
11295 ** FTS5 may be extended with:
11296 **
11297 **     * custom tokenizers, and
11298 **     * custom auxiliary functions.
11299 */
11300 
11301 
11302 #ifndef _FTS5_H
11303 #define _FTS5_H
11304 
11305 
11306 #ifdef __cplusplus
11307 extern "C" {
11308 #endif
11309 
11310 /*************************************************************************
11311 ** CUSTOM AUXILIARY FUNCTIONS
11312 **
11313 ** Virtual table implementations may overload SQL functions by implementing
11314 ** the sqlite3_module.xFindFunction() method.
11315 */
11316 
11317 typedef struct Fts5ExtensionApi Fts5ExtensionApi;
11318 typedef struct Fts5Context Fts5Context;
11319 typedef struct Fts5PhraseIter Fts5PhraseIter;
11320 
11321 typedef void (*fts5_extension_function)(
11322   const Fts5ExtensionApi *pApi,   /* API offered by current FTS version */
11323   Fts5Context *pFts,              /* First arg to pass to pApi functions */
11324   sqlite3_context *pCtx,          /* Context for returning result/error */
11325   int nVal,                       /* Number of values in apVal[] array */
11326   sqlite3_value **apVal           /* Array of trailing arguments */
11327 );
11328 
11329 struct Fts5PhraseIter {
11330   const unsigned char *a;
11331   const unsigned char *b;
11332 };
11333 
11334 /*
11335 ** EXTENSION API FUNCTIONS
11336 **
11337 ** xUserData(pFts):
11338 **   Return a copy of the context pointer the extension function was
11339 **   registered with.
11340 **
11341 ** xColumnTotalSize(pFts, iCol, pnToken):
11342 **   If parameter iCol is less than zero, set output variable *pnToken
11343 **   to the total number of tokens in the FTS5 table. Or, if iCol is
11344 **   non-negative but less than the number of columns in the table, return
11345 **   the total number of tokens in column iCol, considering all rows in
11346 **   the FTS5 table.
11347 **
11348 **   If parameter iCol is greater than or equal to the number of columns
11349 **   in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g.
11350 **   an OOM condition or IO error), an appropriate SQLite error code is
11351 **   returned.
11352 **
11353 ** xColumnCount(pFts):
11354 **   Return the number of columns in the table.
11355 **
11356 ** xColumnSize(pFts, iCol, pnToken):
11357 **   If parameter iCol is less than zero, set output variable *pnToken
11358 **   to the total number of tokens in the current row. Or, if iCol is
11359 **   non-negative but less than the number of columns in the table, set
11360 **   *pnToken to the number of tokens in column iCol of the current row.
11361 **
11362 **   If parameter iCol is greater than or equal to the number of columns
11363 **   in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g.
11364 **   an OOM condition or IO error), an appropriate SQLite error code is
11365 **   returned.
11366 **
11367 **   This function may be quite inefficient if used with an FTS5 table
11368 **   created with the "columnsize=0" option.
11369 **
11370 ** xColumnText:
11371 **   This function attempts to retrieve the text of column iCol of the
11372 **   current document. If successful, (*pz) is set to point to a buffer
11373 **   containing the text in utf-8 encoding, (*pn) is set to the size in bytes
11374 **   (not characters) of the buffer and SQLITE_OK is returned. Otherwise,
11375 **   if an error occurs, an SQLite error code is returned and the final values
11376 **   of (*pz) and (*pn) are undefined.
11377 **
11378 ** xPhraseCount:
11379 **   Returns the number of phrases in the current query expression.
11380 **
11381 ** xPhraseSize:
11382 **   Returns the number of tokens in phrase iPhrase of the query. Phrases
11383 **   are numbered starting from zero.
11384 **
11385 ** xInstCount:
11386 **   Set *pnInst to the total number of occurrences of all phrases within
11387 **   the query within the current row. Return SQLITE_OK if successful, or
11388 **   an error code (i.e. SQLITE_NOMEM) if an error occurs.
11389 **
11390 **   This API can be quite slow if used with an FTS5 table created with the
11391 **   "detail=none" or "detail=column" option. If the FTS5 table is created
11392 **   with either "detail=none" or "detail=column" and "content=" option
11393 **   (i.e. if it is a contentless table), then this API always returns 0.
11394 **
11395 ** xInst:
11396 **   Query for the details of phrase match iIdx within the current row.
11397 **   Phrase matches are numbered starting from zero, so the iIdx argument
11398 **   should be greater than or equal to zero and smaller than the value
11399 **   output by xInstCount().
11400 **
11401 **   Usually, output parameter *piPhrase is set to the phrase number, *piCol
11402 **   to the column in which it occurs and *piOff the token offset of the
11403 **   first token of the phrase. Returns SQLITE_OK if successful, or an error
11404 **   code (i.e. SQLITE_NOMEM) if an error occurs.
11405 **
11406 **   This API can be quite slow if used with an FTS5 table created with the
11407 **   "detail=none" or "detail=column" option.
11408 **
11409 ** xRowid:
11410 **   Returns the rowid of the current row.
11411 **
11412 ** xTokenize:
11413 **   Tokenize text using the tokenizer belonging to the FTS5 table.
11414 **
11415 ** xQueryPhrase(pFts5, iPhrase, pUserData, xCallback):
11416 **   This API function is used to query the FTS table for phrase iPhrase
11417 **   of the current query. Specifically, a query equivalent to:
11418 **
11419 **       ... FROM ftstable WHERE ftstable MATCH $p ORDER BY rowid
11420 **
11421 **   with $p set to a phrase equivalent to the phrase iPhrase of the
11422 **   current query is executed. Any column filter that applies to
11423 **   phrase iPhrase of the current query is included in $p. For each
11424 **   row visited, the callback function passed as the fourth argument
11425 **   is invoked. The context and API objects passed to the callback
11426 **   function may be used to access the properties of each matched row.
11427 **   Invoking Api.xUserData() returns a copy of the pointer passed as
11428 **   the third argument to pUserData.
11429 **
11430 **   If the callback function returns any value other than SQLITE_OK, the
11431 **   query is abandoned and the xQueryPhrase function returns immediately.
11432 **   If the returned value is SQLITE_DONE, xQueryPhrase returns SQLITE_OK.
11433 **   Otherwise, the error code is propagated upwards.
11434 **
11435 **   If the query runs to completion without incident, SQLITE_OK is returned.
11436 **   Or, if some error occurs before the query completes or is aborted by
11437 **   the callback, an SQLite error code is returned.
11438 **
11439 **
11440 ** xSetAuxdata(pFts5, pAux, xDelete)
11441 **
11442 **   Save the pointer passed as the second argument as the extension functions
11443 **   "auxiliary data". The pointer may then be retrieved by the current or any
11444 **   future invocation of the same fts5 extension function made as part of
11445 **   the same MATCH query using the xGetAuxdata() API.
11446 **
11447 **   Each extension function is allocated a single auxiliary data slot for
11448 **   each FTS query (MATCH expression). If the extension function is invoked
11449 **   more than once for a single FTS query, then all invocations share a
11450 **   single auxiliary data context.
11451 **
11452 **   If there is already an auxiliary data pointer when this function is
11453 **   invoked, then it is replaced by the new pointer. If an xDelete callback
11454 **   was specified along with the original pointer, it is invoked at this
11455 **   point.
11456 **
11457 **   The xDelete callback, if one is specified, is also invoked on the
11458 **   auxiliary data pointer after the FTS5 query has finished.
11459 **
11460 **   If an error (e.g. an OOM condition) occurs within this function,
11461 **   the auxiliary data is set to NULL and an error code returned. If the
11462 **   xDelete parameter was not NULL, it is invoked on the auxiliary data
11463 **   pointer before returning.
11464 **
11465 **
11466 ** xGetAuxdata(pFts5, bClear)
11467 **
11468 **   Returns the current auxiliary data pointer for the fts5 extension
11469 **   function. See the xSetAuxdata() method for details.
11470 **
11471 **   If the bClear argument is non-zero, then the auxiliary data is cleared
11472 **   (set to NULL) before this function returns. In this case the xDelete,
11473 **   if any, is not invoked.
11474 **
11475 **
11476 ** xRowCount(pFts5, pnRow)
11477 **
11478 **   This function is used to retrieve the total number of rows in the table.
11479 **   In other words, the same value that would be returned by:
11480 **
11481 **        SELECT count(*) FROM ftstable;
11482 **
11483 ** xPhraseFirst()
11484 **   This function is used, along with type Fts5PhraseIter and the xPhraseNext
11485 **   method, to iterate through all instances of a single query phrase within
11486 **   the current row. This is the same information as is accessible via the
11487 **   xInstCount/xInst APIs. While the xInstCount/xInst APIs are more convenient
11488 **   to use, this API may be faster under some circumstances. To iterate
11489 **   through instances of phrase iPhrase, use the following code:
11490 **
11491 **       Fts5PhraseIter iter;
11492 **       int iCol, iOff;
11493 **       for(pApi->xPhraseFirst(pFts, iPhrase, &iter, &iCol, &iOff);
11494 **           iCol>=0;
11495 **           pApi->xPhraseNext(pFts, &iter, &iCol, &iOff)
11496 **       ){
11497 **         // An instance of phrase iPhrase at offset iOff of column iCol
11498 **       }
11499 **
11500 **   The Fts5PhraseIter structure is defined above. Applications should not
11501 **   modify this structure directly - it should only be used as shown above
11502 **   with the xPhraseFirst() and xPhraseNext() API methods (and by
11503 **   xPhraseFirstColumn() and xPhraseNextColumn() as illustrated below).
11504 **
11505 **   This API can be quite slow if used with an FTS5 table created with the
11506 **   "detail=none" or "detail=column" option. If the FTS5 table is created
11507 **   with either "detail=none" or "detail=column" and "content=" option
11508 **   (i.e. if it is a contentless table), then this API always iterates
11509 **   through an empty set (all calls to xPhraseFirst() set iCol to -1).
11510 **
11511 ** xPhraseNext()
11512 **   See xPhraseFirst above.
11513 **
11514 ** xPhraseFirstColumn()
11515 **   This function and xPhraseNextColumn() are similar to the xPhraseFirst()
11516 **   and xPhraseNext() APIs described above. The difference is that instead
11517 **   of iterating through all instances of a phrase in the current row, these
11518 **   APIs are used to iterate through the set of columns in the current row
11519 **   that contain one or more instances of a specified phrase. For example:
11520 **
11521 **       Fts5PhraseIter iter;
11522 **       int iCol;
11523 **       for(pApi->xPhraseFirstColumn(pFts, iPhrase, &iter, &iCol);
11524 **           iCol>=0;
11525 **           pApi->xPhraseNextColumn(pFts, &iter, &iCol)
11526 **       ){
11527 **         // Column iCol contains at least one instance of phrase iPhrase
11528 **       }
11529 **
11530 **   This API can be quite slow if used with an FTS5 table created with the
11531 **   "detail=none" option. If the FTS5 table is created with either
11532 **   "detail=none" "content=" option (i.e. if it is a contentless table),
11533 **   then this API always iterates through an empty set (all calls to
11534 **   xPhraseFirstColumn() set iCol to -1).
11535 **
11536 **   The information accessed using this API and its companion
11537 **   xPhraseFirstColumn() may also be obtained using xPhraseFirst/xPhraseNext
11538 **   (or xInst/xInstCount). The chief advantage of this API is that it is
11539 **   significantly more efficient than those alternatives when used with
11540 **   "detail=column" tables.
11541 **
11542 ** xPhraseNextColumn()
11543 **   See xPhraseFirstColumn above.
11544 */
11545 struct Fts5ExtensionApi {
11546   int iVersion;                   /* Currently always set to 3 */
11547 
11548   void *(*xUserData)(Fts5Context*);
11549 
11550   int (*xColumnCount)(Fts5Context*);
11551   int (*xRowCount)(Fts5Context*, sqlite3_int64 *pnRow);
11552   int (*xColumnTotalSize)(Fts5Context*, int iCol, sqlite3_int64 *pnToken);
11553 
11554   int (*xTokenize)(Fts5Context*,
11555     const char *pText, int nText, /* Text to tokenize */
11556     void *pCtx,                   /* Context passed to xToken() */
11557     int (*xToken)(void*, int, const char*, int, int, int)       /* Callback */
11558   );
11559 
11560   int (*xPhraseCount)(Fts5Context*);
11561   int (*xPhraseSize)(Fts5Context*, int iPhrase);
11562 
11563   int (*xInstCount)(Fts5Context*, int *pnInst);
11564   int (*xInst)(Fts5Context*, int iIdx, int *piPhrase, int *piCol, int *piOff);
11565 
11566   sqlite3_int64 (*xRowid)(Fts5Context*);
11567   int (*xColumnText)(Fts5Context*, int iCol, const char **pz, int *pn);
11568   int (*xColumnSize)(Fts5Context*, int iCol, int *pnToken);
11569 
11570   int (*xQueryPhrase)(Fts5Context*, int iPhrase, void *pUserData,
11571     int(*)(const Fts5ExtensionApi*,Fts5Context*,void*)
11572   );
11573   int (*xSetAuxdata)(Fts5Context*, void *pAux, void(*xDelete)(void*));
11574   void *(*xGetAuxdata)(Fts5Context*, int bClear);
11575 
11576   int (*xPhraseFirst)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*, int*);
11577   void (*xPhraseNext)(Fts5Context*, Fts5PhraseIter*, int *piCol, int *piOff);
11578 
11579   int (*xPhraseFirstColumn)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*);
11580   void (*xPhraseNextColumn)(Fts5Context*, Fts5PhraseIter*, int *piCol);
11581 };
11582 
11583 /*
11584 ** CUSTOM AUXILIARY FUNCTIONS
11585 *************************************************************************/
11586 
11587 /*************************************************************************
11588 ** CUSTOM TOKENIZERS
11589 **
11590 ** Applications may also register custom tokenizer types. A tokenizer
11591 ** is registered by providing fts5 with a populated instance of the
11592 ** following structure. All structure methods must be defined, setting
11593 ** any member of the fts5_tokenizer struct to NULL leads to undefined
11594 ** behaviour. The structure methods are expected to function as follows:
11595 **
11596 ** xCreate:
11597 **   This function is used to allocate and initialize a tokenizer instance.
11598 **   A tokenizer instance is required to actually tokenize text.
11599 **
11600 **   The first argument passed to this function is a copy of the (void*)
11601 **   pointer provided by the application when the fts5_tokenizer object
11602 **   was registered with FTS5 (the third argument to xCreateTokenizer()).
11603 **   The second and third arguments are an array of nul-terminated strings
11604 **   containing the tokenizer arguments, if any, specified following the
11605 **   tokenizer name as part of the CREATE VIRTUAL TABLE statement used
11606 **   to create the FTS5 table.
11607 **
11608 **   The final argument is an output variable. If successful, (*ppOut)
11609 **   should be set to point to the new tokenizer handle and SQLITE_OK
11610 **   returned. If an error occurs, some value other than SQLITE_OK should
11611 **   be returned. In this case, fts5 assumes that the final value of *ppOut
11612 **   is undefined.
11613 **
11614 ** xDelete:
11615 **   This function is invoked to delete a tokenizer handle previously
11616 **   allocated using xCreate(). Fts5 guarantees that this function will
11617 **   be invoked exactly once for each successful call to xCreate().
11618 **
11619 ** xTokenize:
11620 **   This function is expected to tokenize the nText byte string indicated
11621 **   by argument pText. pText may or may not be nul-terminated. The first
11622 **   argument passed to this function is a pointer to an Fts5Tokenizer object
11623 **   returned by an earlier call to xCreate().
11624 **
11625 **   The second argument indicates the reason that FTS5 is requesting
11626 **   tokenization of the supplied text. This is always one of the following
11627 **   four values:
11628 **
11629 **   <ul><li> <b>FTS5_TOKENIZE_DOCUMENT</b> - A document is being inserted into
11630 **            or removed from the FTS table. The tokenizer is being invoked to
11631 **            determine the set of tokens to add to (or delete from) the
11632 **            FTS index.
11633 **
11634 **       <li> <b>FTS5_TOKENIZE_QUERY</b> - A MATCH query is being executed
11635 **            against the FTS index. The tokenizer is being called to tokenize
11636 **            a bareword or quoted string specified as part of the query.
11637 **
11638 **       <li> <b>(FTS5_TOKENIZE_QUERY | FTS5_TOKENIZE_PREFIX)</b> - Same as
11639 **            FTS5_TOKENIZE_QUERY, except that the bareword or quoted string is
11640 **            followed by a "*" character, indicating that the last token
11641 **            returned by the tokenizer will be treated as a token prefix.
11642 **
11643 **       <li> <b>FTS5_TOKENIZE_AUX</b> - The tokenizer is being invoked to
11644 **            satisfy an fts5_api.xTokenize() request made by an auxiliary
11645 **            function. Or an fts5_api.xColumnSize() request made by the same
11646 **            on a columnsize=0 database.
11647 **   </ul>
11648 **
11649 **   For each token in the input string, the supplied callback xToken() must
11650 **   be invoked. The first argument to it should be a copy of the pointer
11651 **   passed as the second argument to xTokenize(). The third and fourth
11652 **   arguments are a pointer to a buffer containing the token text, and the
11653 **   size of the token in bytes. The 4th and 5th arguments are the byte offsets
11654 **   of the first byte of and first byte immediately following the text from
11655 **   which the token is derived within the input.
11656 **
11657 **   The second argument passed to the xToken() callback ("tflags") should
11658 **   normally be set to 0. The exception is if the tokenizer supports
11659 **   synonyms. In this case see the discussion below for details.
11660 **
11661 **   FTS5 assumes the xToken() callback is invoked for each token in the
11662 **   order that they occur within the input text.
11663 **
11664 **   If an xToken() callback returns any value other than SQLITE_OK, then
11665 **   the tokenization should be abandoned and the xTokenize() method should
11666 **   immediately return a copy of the xToken() return value. Or, if the
11667 **   input buffer is exhausted, xTokenize() should return SQLITE_OK. Finally,
11668 **   if an error occurs with the xTokenize() implementation itself, it
11669 **   may abandon the tokenization and return any error code other than
11670 **   SQLITE_OK or SQLITE_DONE.
11671 **
11672 ** SYNONYM SUPPORT
11673 **
11674 **   Custom tokenizers may also support synonyms. Consider a case in which a
11675 **   user wishes to query for a phrase such as "first place". Using the
11676 **   built-in tokenizers, the FTS5 query 'first + place' will match instances
11677 **   of "first place" within the document set, but not alternative forms
11678 **   such as "1st place". In some applications, it would be better to match
11679 **   all instances of "first place" or "1st place" regardless of which form
11680 **   the user specified in the MATCH query text.
11681 **
11682 **   There are several ways to approach this in FTS5:
11683 **
11684 **   <ol><li> By mapping all synonyms to a single token. In this case, the
11685 **            In the above example, this means that the tokenizer returns the
11686 **            same token for inputs "first" and "1st". Say that token is in
11687 **            fact "first", so that when the user inserts the document "I won
11688 **            1st place" entries are added to the index for tokens "i", "won",
11689 **            "first" and "place". If the user then queries for '1st + place',
11690 **            the tokenizer substitutes "first" for "1st" and the query works
11691 **            as expected.
11692 **
11693 **       <li> By querying the index for all synonyms of each query term
11694 **            separately. In this case, when tokenizing query text, the
11695 **            tokenizer may provide multiple synonyms for a single term
11696 **            within the document. FTS5 then queries the index for each
11697 **            synonym individually. For example, faced with the query:
11698 **
11699 **   <codeblock>
11700 **     ... MATCH 'first place'</codeblock>
11701 **
11702 **            the tokenizer offers both "1st" and "first" as synonyms for the
11703 **            first token in the MATCH query and FTS5 effectively runs a query
11704 **            similar to:
11705 **
11706 **   <codeblock>
11707 **     ... MATCH '(first OR 1st) place'</codeblock>
11708 **
11709 **            except that, for the purposes of auxiliary functions, the query
11710 **            still appears to contain just two phrases - "(first OR 1st)"
11711 **            being treated as a single phrase.
11712 **
11713 **       <li> By adding multiple synonyms for a single term to the FTS index.
11714 **            Using this method, when tokenizing document text, the tokenizer
11715 **            provides multiple synonyms for each token. So that when a
11716 **            document such as "I won first place" is tokenized, entries are
11717 **            added to the FTS index for "i", "won", "first", "1st" and
11718 **            "place".
11719 **
11720 **            This way, even if the tokenizer does not provide synonyms
11721 **            when tokenizing query text (it should not - to do so would be
11722 **            inefficient), it doesn't matter if the user queries for
11723 **            'first + place' or '1st + place', as there are entries in the
11724 **            FTS index corresponding to both forms of the first token.
11725 **   </ol>
11726 **
11727 **   Whether it is parsing document or query text, any call to xToken that
11728 **   specifies a <i>tflags</i> argument with the FTS5_TOKEN_COLOCATED bit
11729 **   is considered to supply a synonym for the previous token. For example,
11730 **   when parsing the document "I won first place", a tokenizer that supports
11731 **   synonyms would call xToken() 5 times, as follows:
11732 **
11733 **   <codeblock>
11734 **       xToken(pCtx, 0, "i",                      1,  0,  1);
11735 **       xToken(pCtx, 0, "won",                    3,  2,  5);
11736 **       xToken(pCtx, 0, "first",                  5,  6, 11);
11737 **       xToken(pCtx, FTS5_TOKEN_COLOCATED, "1st", 3,  6, 11);
11738 **       xToken(pCtx, 0, "place",                  5, 12, 17);
11739 **</codeblock>
11740 **
11741 **   It is an error to specify the FTS5_TOKEN_COLOCATED flag the first time
11742 **   xToken() is called. Multiple synonyms may be specified for a single token
11743 **   by making multiple calls to xToken(FTS5_TOKEN_COLOCATED) in sequence.
11744 **   There is no limit to the number of synonyms that may be provided for a
11745 **   single token.
11746 **
11747 **   In many cases, method (1) above is the best approach. It does not add
11748 **   extra data to the FTS index or require FTS5 to query for multiple terms,
11749 **   so it is efficient in terms of disk space and query speed. However, it
11750 **   does not support prefix queries very well. If, as suggested above, the
11751 **   token "first" is substituted for "1st" by the tokenizer, then the query:
11752 **
11753 **   <codeblock>
11754 **     ... MATCH '1s*'</codeblock>
11755 **
11756 **   will not match documents that contain the token "1st" (as the tokenizer
11757 **   will probably not map "1s" to any prefix of "first").
11758 **
11759 **   For full prefix support, method (3) may be preferred. In this case,
11760 **   because the index contains entries for both "first" and "1st", prefix
11761 **   queries such as 'fi*' or '1s*' will match correctly. However, because
11762 **   extra entries are added to the FTS index, this method uses more space
11763 **   within the database.
11764 **
11765 **   Method (2) offers a midpoint between (1) and (3). Using this method,
11766 **   a query such as '1s*' will match documents that contain the literal
11767 **   token "1st", but not "first" (assuming the tokenizer is not able to
11768 **   provide synonyms for prefixes). However, a non-prefix query like '1st'
11769 **   will match against "1st" and "first". This method does not require
11770 **   extra disk space, as no extra entries are added to the FTS index.
11771 **   On the other hand, it may require more CPU cycles to run MATCH queries,
11772 **   as separate queries of the FTS index are required for each synonym.
11773 **
11774 **   When using methods (2) or (3), it is important that the tokenizer only
11775 **   provide synonyms when tokenizing document text (method (2)) or query
11776 **   text (method (3)), not both. Doing so will not cause any errors, but is
11777 **   inefficient.
11778 */
11779 typedef struct Fts5Tokenizer Fts5Tokenizer;
11780 typedef struct fts5_tokenizer fts5_tokenizer;
11781 struct fts5_tokenizer {
11782   int (*xCreate)(void*, const char **azArg, int nArg, Fts5Tokenizer **ppOut);
11783   void (*xDelete)(Fts5Tokenizer*);
11784   int (*xTokenize)(Fts5Tokenizer*,
11785       void *pCtx,
11786       int flags,            /* Mask of FTS5_TOKENIZE_* flags */
11787       const char *pText, int nText,
11788       int (*xToken)(
11789         void *pCtx,         /* Copy of 2nd argument to xTokenize() */
11790         int tflags,         /* Mask of FTS5_TOKEN_* flags */
11791         const char *pToken, /* Pointer to buffer containing token */
11792         int nToken,         /* Size of token in bytes */
11793         int iStart,         /* Byte offset of token within input text */
11794         int iEnd            /* Byte offset of end of token within input text */
11795       )
11796   );
11797 };
11798 
11799 /* Flags that may be passed as the third argument to xTokenize() */
11800 #define FTS5_TOKENIZE_QUERY     0x0001
11801 #define FTS5_TOKENIZE_PREFIX    0x0002
11802 #define FTS5_TOKENIZE_DOCUMENT  0x0004
11803 #define FTS5_TOKENIZE_AUX       0x0008
11804 
11805 /* Flags that may be passed by the tokenizer implementation back to FTS5
11806 ** as the third argument to the supplied xToken callback. */
11807 #define FTS5_TOKEN_COLOCATED    0x0001      /* Same position as prev. token */
11808 
11809 /*
11810 ** END OF CUSTOM TOKENIZERS
11811 *************************************************************************/
11812 
11813 /*************************************************************************
11814 ** FTS5 EXTENSION REGISTRATION API
11815 */
11816 typedef struct fts5_api fts5_api;
11817 struct fts5_api {
11818   int iVersion;                   /* Currently always set to 2 */
11819 
11820   /* Create a new tokenizer */
11821   int (*xCreateTokenizer)(
11822     fts5_api *pApi,
11823     const char *zName,
11824     void *pContext,
11825     fts5_tokenizer *pTokenizer,
11826     void (*xDestroy)(void*)
11827   );
11828 
11829   /* Find an existing tokenizer */
11830   int (*xFindTokenizer)(
11831     fts5_api *pApi,
11832     const char *zName,
11833     void **ppContext,
11834     fts5_tokenizer *pTokenizer
11835   );
11836 
11837   /* Create a new auxiliary function */
11838   int (*xCreateFunction)(
11839     fts5_api *pApi,
11840     const char *zName,
11841     void *pContext,
11842     fts5_extension_function xFunction,
11843     void (*xDestroy)(void*)
11844   );
11845 };
11846 
11847 /*
11848 ** END OF REGISTRATION API
11849 *************************************************************************/
11850 
11851 #ifdef __cplusplus
11852 }  /* end of the 'extern "C"' block */
11853 #endif
11854 
11855 #endif /* _FTS5_H */
11856 
11857 /******** End of fts5.h *********/
11858