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. 119 ** 120 ** See also: [sqlite3_libversion()], 121 ** [sqlite3_libversion_number()], [sqlite3_sourceid()], 122 ** [sqlite_version()] and [sqlite_source_id()]. 123 */ 124 #define SQLITE_VERSION "3.20.0" 125 #define SQLITE_VERSION_NUMBER 3020000 126 #define SQLITE_SOURCE_ID "2017-08-01 13:24:15 9501e22dfeebdcefa783575e47c60b514d7c2e0cad73b2a496c0bc4b680900a8" 127 128 /* 129 ** CAPI3REF: Run-Time Library Version Numbers 130 ** KEYWORDS: sqlite3_version sqlite3_sourceid 131 ** 132 ** These interfaces provide the same information as the [SQLITE_VERSION], 133 ** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros 134 ** but are associated with the library instead of the header file. ^(Cautious 135 ** programmers might include assert() statements in their application to 136 ** verify that values returned by these interfaces match the macros in 137 ** the header, and thus ensure that the application is 138 ** compiled with matching library and header files. 139 ** 140 ** <blockquote><pre> 141 ** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER ); 142 ** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 ); 143 ** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 ); 144 ** </pre></blockquote>)^ 145 ** 146 ** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION] 147 ** macro. ^The sqlite3_libversion() function returns a pointer to the 148 ** to the sqlite3_version[] string constant. The sqlite3_libversion() 149 ** function is provided for use in DLLs since DLL users usually do not have 150 ** direct access to string constants within the DLL. ^The 151 ** sqlite3_libversion_number() function returns an integer equal to 152 ** [SQLITE_VERSION_NUMBER]. ^The sqlite3_sourceid() function returns 153 ** a pointer to a string constant whose value is the same as the 154 ** [SQLITE_SOURCE_ID] C preprocessor macro. 155 ** 156 ** See also: [sqlite_version()] and [sqlite_source_id()]. 157 */ 158 SQLITE_API SQLITE_EXTERN const char sqlite3_version[]; 159 SQLITE_API const char *sqlite3_libversion(void); 160 SQLITE_API const char *sqlite3_sourceid(void); 161 SQLITE_API int sqlite3_libversion_number(void); 162 163 /* 164 ** CAPI3REF: Run-Time Library Compilation Options Diagnostics 165 ** 166 ** ^The sqlite3_compileoption_used() function returns 0 or 1 167 ** indicating whether the specified option was defined at 168 ** compile time. ^The SQLITE_ prefix may be omitted from the 169 ** option name passed to sqlite3_compileoption_used(). 170 ** 171 ** ^The sqlite3_compileoption_get() function allows iterating 172 ** over the list of options that were defined at compile time by 173 ** returning the N-th compile time option string. ^If N is out of range, 174 ** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_ 175 ** prefix is omitted from any strings returned by 176 ** sqlite3_compileoption_get(). 177 ** 178 ** ^Support for the diagnostic functions sqlite3_compileoption_used() 179 ** and sqlite3_compileoption_get() may be omitted by specifying the 180 ** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time. 181 ** 182 ** See also: SQL functions [sqlite_compileoption_used()] and 183 ** [sqlite_compileoption_get()] and the [compile_options pragma]. 184 */ 185 #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS 186 SQLITE_API int sqlite3_compileoption_used(const char *zOptName); 187 SQLITE_API const char *sqlite3_compileoption_get(int N); 188 #endif 189 190 /* 191 ** CAPI3REF: Test To See If The Library Is Threadsafe 192 ** 193 ** ^The sqlite3_threadsafe() function returns zero if and only if 194 ** SQLite was compiled with mutexing code omitted due to the 195 ** [SQLITE_THREADSAFE] compile-time option being set to 0. 196 ** 197 ** SQLite can be compiled with or without mutexes. When 198 ** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes 199 ** are enabled and SQLite is threadsafe. When the 200 ** [SQLITE_THREADSAFE] macro is 0, 201 ** the mutexes are omitted. Without the mutexes, it is not safe 202 ** to use SQLite concurrently from more than one thread. 203 ** 204 ** Enabling mutexes incurs a measurable performance penalty. 205 ** So if speed is of utmost importance, it makes sense to disable 206 ** the mutexes. But for maximum safety, mutexes should be enabled. 207 ** ^The default behavior is for mutexes to be enabled. 208 ** 209 ** This interface can be used by an application to make sure that the 210 ** version of SQLite that it is linking against was compiled with 211 ** the desired setting of the [SQLITE_THREADSAFE] macro. 212 ** 213 ** This interface only reports on the compile-time mutex setting 214 ** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with 215 ** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but 216 ** can be fully or partially disabled using a call to [sqlite3_config()] 217 ** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], 218 ** or [SQLITE_CONFIG_SERIALIZED]. ^(The return value of the 219 ** sqlite3_threadsafe() function shows only the compile-time setting of 220 ** thread safety, not any run-time changes to that setting made by 221 ** sqlite3_config(). In other words, the return value from sqlite3_threadsafe() 222 ** is unchanged by calls to sqlite3_config().)^ 223 ** 224 ** See the [threading mode] documentation for additional information. 225 */ 226 SQLITE_API int sqlite3_threadsafe(void); 227 228 /* 229 ** CAPI3REF: Database Connection Handle 230 ** KEYWORDS: {database connection} {database connections} 231 ** 232 ** Each open SQLite database is represented by a pointer to an instance of 233 ** the opaque structure named "sqlite3". It is useful to think of an sqlite3 234 ** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and 235 ** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] 236 ** and [sqlite3_close_v2()] are its destructors. There are many other 237 ** interfaces (such as 238 ** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 239 ** [sqlite3_busy_timeout()] to name but three) that are methods on an 240 ** sqlite3 object. 241 */ 242 typedef struct sqlite3 sqlite3; 243 244 /* 245 ** CAPI3REF: 64-Bit Integer Types 246 ** KEYWORDS: sqlite_int64 sqlite_uint64 247 ** 248 ** Because there is no cross-platform way to specify 64-bit integer types 249 ** SQLite includes typedefs for 64-bit signed and unsigned integers. 250 ** 251 ** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 252 ** The sqlite_int64 and sqlite_uint64 types are supported for backwards 253 ** compatibility only. 254 ** 255 ** ^The sqlite3_int64 and sqlite_int64 types can store integer values 256 ** between -9223372036854775808 and +9223372036854775807 inclusive. ^The 257 ** sqlite3_uint64 and sqlite_uint64 types can store integer values 258 ** between 0 and +18446744073709551615 inclusive. 259 */ 260 #ifdef SQLITE_INT64_TYPE 261 typedef SQLITE_INT64_TYPE sqlite_int64; 262 # ifdef SQLITE_UINT64_TYPE 263 typedef SQLITE_UINT64_TYPE sqlite_uint64; 264 # else 265 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 266 # endif 267 #elif defined(_MSC_VER) || defined(__BORLANDC__) 268 typedef __int64 sqlite_int64; 269 typedef unsigned __int64 sqlite_uint64; 270 #else 271 typedef long long int sqlite_int64; 272 typedef unsigned long long int sqlite_uint64; 273 #endif 274 typedef sqlite_int64 sqlite3_int64; 275 typedef sqlite_uint64 sqlite3_uint64; 276 277 /* 278 ** If compiling for a processor that lacks floating point support, 279 ** substitute integer for floating-point. 280 */ 281 #ifdef SQLITE_OMIT_FLOATING_POINT 282 # define double sqlite3_int64 283 #endif 284 285 /* 286 ** CAPI3REF: Closing A Database Connection 287 ** DESTRUCTOR: sqlite3 288 ** 289 ** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors 290 ** for the [sqlite3] object. 291 ** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if 292 ** the [sqlite3] object is successfully destroyed and all associated 293 ** resources are deallocated. 294 ** 295 ** ^If the database connection is associated with unfinalized prepared 296 ** statements or unfinished sqlite3_backup objects then sqlite3_close() 297 ** will leave the database connection open and return [SQLITE_BUSY]. 298 ** ^If sqlite3_close_v2() is called with unfinalized prepared statements 299 ** and/or unfinished sqlite3_backups, then the database connection becomes 300 ** an unusable "zombie" which will automatically be deallocated when the 301 ** last prepared statement is finalized or the last sqlite3_backup is 302 ** finished. The sqlite3_close_v2() interface is intended for use with 303 ** host languages that are garbage collected, and where the order in which 304 ** destructors are called is arbitrary. 305 ** 306 ** Applications should [sqlite3_finalize | finalize] all [prepared statements], 307 ** [sqlite3_blob_close | close] all [BLOB handles], and 308 ** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated 309 ** with the [sqlite3] object prior to attempting to close the object. ^If 310 ** sqlite3_close_v2() is called on a [database connection] that still has 311 ** outstanding [prepared statements], [BLOB handles], and/or 312 ** [sqlite3_backup] objects then it returns [SQLITE_OK] and the deallocation 313 ** of resources is deferred until all [prepared statements], [BLOB handles], 314 ** and [sqlite3_backup] objects are also destroyed. 315 ** 316 ** ^If an [sqlite3] object is destroyed while a transaction is open, 317 ** the transaction is automatically rolled back. 318 ** 319 ** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)] 320 ** must be either a NULL 321 ** pointer or an [sqlite3] object pointer obtained 322 ** from [sqlite3_open()], [sqlite3_open16()], or 323 ** [sqlite3_open_v2()], and not previously closed. 324 ** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer 325 ** argument is a harmless no-op. 326 */ 327 SQLITE_API int sqlite3_close(sqlite3*); 328 SQLITE_API int sqlite3_close_v2(sqlite3*); 329 330 /* 331 ** The type for a callback function. 332 ** This is legacy and deprecated. It is included for historical 333 ** compatibility and is not documented. 334 */ 335 typedef int (*sqlite3_callback)(void*,int,char**, char**); 336 337 /* 338 ** CAPI3REF: One-Step Query Execution Interface 339 ** METHOD: sqlite3 340 ** 341 ** The sqlite3_exec() interface is a convenience wrapper around 342 ** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], 343 ** that allows an application to run multiple statements of SQL 344 ** without having to use a lot of C code. 345 ** 346 ** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, 347 ** semicolon-separate SQL statements passed into its 2nd argument, 348 ** in the context of the [database connection] passed in as its 1st 349 ** argument. ^If the callback function of the 3rd argument to 350 ** sqlite3_exec() is not NULL, then it is invoked for each result row 351 ** coming out of the evaluated SQL statements. ^The 4th argument to 352 ** sqlite3_exec() is relayed through to the 1st argument of each 353 ** callback invocation. ^If the callback pointer to sqlite3_exec() 354 ** is NULL, then no callback is ever invoked and result rows are 355 ** ignored. 356 ** 357 ** ^If an error occurs while evaluating the SQL statements passed into 358 ** sqlite3_exec(), then execution of the current statement stops and 359 ** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() 360 ** is not NULL then any error message is written into memory obtained 361 ** from [sqlite3_malloc()] and passed back through the 5th parameter. 362 ** To avoid memory leaks, the application should invoke [sqlite3_free()] 363 ** on error message strings returned through the 5th parameter of 364 ** sqlite3_exec() after the error message string is no longer needed. 365 ** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors 366 ** occur, then sqlite3_exec() sets the pointer in its 5th parameter to 367 ** NULL before returning. 368 ** 369 ** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() 370 ** routine returns SQLITE_ABORT without invoking the callback again and 371 ** without running any subsequent SQL statements. 372 ** 373 ** ^The 2nd argument to the sqlite3_exec() callback function is the 374 ** number of columns in the result. ^The 3rd argument to the sqlite3_exec() 375 ** callback is an array of pointers to strings obtained as if from 376 ** [sqlite3_column_text()], one for each column. ^If an element of a 377 ** result row is NULL then the corresponding string pointer for the 378 ** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the 379 ** sqlite3_exec() callback is an array of pointers to strings where each 380 ** entry represents the name of corresponding result column as obtained 381 ** from [sqlite3_column_name()]. 382 ** 383 ** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer 384 ** to an empty string, or a pointer that contains only whitespace and/or 385 ** SQL comments, then no SQL statements are evaluated and the database 386 ** is not changed. 387 ** 388 ** Restrictions: 389 ** 390 ** <ul> 391 ** <li> The application must ensure that the 1st parameter to sqlite3_exec() 392 ** is a valid and open [database connection]. 393 ** <li> The application must not close the [database connection] specified by 394 ** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running. 395 ** <li> The application must not modify the SQL statement text passed into 396 ** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running. 397 ** </ul> 398 */ 399 SQLITE_API int sqlite3_exec( 400 sqlite3*, /* An open database */ 401 const char *sql, /* SQL to be evaluated */ 402 int (*callback)(void*,int,char**,char**), /* Callback function */ 403 void *, /* 1st argument to callback */ 404 char **errmsg /* Error msg written here */ 405 ); 406 407 /* 408 ** CAPI3REF: Result Codes 409 ** KEYWORDS: {result code definitions} 410 ** 411 ** Many SQLite functions return an integer result code from the set shown 412 ** here in order to indicate success or failure. 413 ** 414 ** New error codes may be added in future versions of SQLite. 415 ** 416 ** See also: [extended result code definitions] 417 */ 418 #define SQLITE_OK 0 /* Successful result */ 419 /* beginning-of-error-codes */ 420 #define SQLITE_ERROR 1 /* Generic error */ 421 #define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 422 #define SQLITE_PERM 3 /* Access permission denied */ 423 #define SQLITE_ABORT 4 /* Callback routine requested an abort */ 424 #define SQLITE_BUSY 5 /* The database file is locked */ 425 #define SQLITE_LOCKED 6 /* A table in the database is locked */ 426 #define SQLITE_NOMEM 7 /* A malloc() failed */ 427 #define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 428 #define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 429 #define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 430 #define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 431 #define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */ 432 #define SQLITE_FULL 13 /* Insertion failed because database is full */ 433 #define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 434 #define SQLITE_PROTOCOL 15 /* Database lock protocol error */ 435 #define SQLITE_EMPTY 16 /* Not used */ 436 #define SQLITE_SCHEMA 17 /* The database schema changed */ 437 #define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 438 #define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 439 #define SQLITE_MISMATCH 20 /* Data type mismatch */ 440 #define SQLITE_MISUSE 21 /* Library used incorrectly */ 441 #define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 442 #define SQLITE_AUTH 23 /* Authorization denied */ 443 #define SQLITE_FORMAT 24 /* Not used */ 444 #define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 445 #define SQLITE_NOTADB 26 /* File opened that is not a database file */ 446 #define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */ 447 #define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */ 448 #define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 449 #define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 450 /* end-of-error-codes */ 451 452 /* 453 ** CAPI3REF: Extended Result Codes 454 ** KEYWORDS: {extended result code definitions} 455 ** 456 ** In its default configuration, SQLite API routines return one of 30 integer 457 ** [result codes]. However, experience has shown that many of 458 ** these result codes are too coarse-grained. They do not provide as 459 ** much information about problems as programmers might like. In an effort to 460 ** address this, newer versions of SQLite (version 3.3.8 [dateof:3.3.8] 461 ** and later) include 462 ** support for additional result codes that provide more detailed information 463 ** about errors. These [extended result codes] are enabled or disabled 464 ** on a per database connection basis using the 465 ** [sqlite3_extended_result_codes()] API. Or, the extended code for 466 ** the most recent error can be obtained using 467 ** [sqlite3_extended_errcode()]. 468 */ 469 #define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 470 #define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 471 #define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 472 #define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 473 #define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 474 #define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 475 #define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 476 #define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 477 #define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 478 #define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 479 #define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 480 #define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 481 #define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 482 #define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 483 #define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 484 #define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 485 #define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 486 #define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) 487 #define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) 488 #define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) 489 #define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8)) 490 #define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8)) 491 #define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8)) 492 #define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8)) 493 #define SQLITE_IOERR_GETTEMPPATH (SQLITE_IOERR | (25<<8)) 494 #define SQLITE_IOERR_CONVPATH (SQLITE_IOERR | (26<<8)) 495 #define SQLITE_IOERR_VNODE (SQLITE_IOERR | (27<<8)) 496 #define SQLITE_IOERR_AUTH (SQLITE_IOERR | (28<<8)) 497 #define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) 498 #define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) 499 #define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY | (2<<8)) 500 #define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) 501 #define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8)) 502 #define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8)) 503 #define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN | (4<<8)) 504 #define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8)) 505 #define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8)) 506 #define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8)) 507 #define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8)) 508 #define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8)) 509 #define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8)) 510 #define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8)) 511 #define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8)) 512 #define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8)) 513 #define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8)) 514 #define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8)) 515 #define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8)) 516 #define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8)) 517 #define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8)) 518 #define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8)) 519 #define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT |(10<<8)) 520 #define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8)) 521 #define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8)) 522 #define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING | (1<<8)) 523 #define SQLITE_AUTH_USER (SQLITE_AUTH | (1<<8)) 524 #define SQLITE_OK_LOAD_PERMANENTLY (SQLITE_OK | (1<<8)) 525 526 /* 527 ** CAPI3REF: Flags For File Open Operations 528 ** 529 ** These bit values are intended for use in the 530 ** 3rd parameter to the [sqlite3_open_v2()] interface and 531 ** in the 4th parameter to the [sqlite3_vfs.xOpen] method. 532 */ 533 #define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 534 #define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 535 #define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 536 #define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 537 #define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 538 #define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 539 #define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */ 540 #define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */ 541 #define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 542 #define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 543 #define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 544 #define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 545 #define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 546 #define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 547 #define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 548 #define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 549 #define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 550 #define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 551 #define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 552 #define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ 553 554 /* Reserved: 0x00F00000 */ 555 556 /* 557 ** CAPI3REF: Device Characteristics 558 ** 559 ** The xDeviceCharacteristics method of the [sqlite3_io_methods] 560 ** object returns an integer which is a vector of these 561 ** bit values expressing I/O characteristics of the mass storage 562 ** device that holds the file that the [sqlite3_io_methods] 563 ** refers to. 564 ** 565 ** The SQLITE_IOCAP_ATOMIC property means that all writes of 566 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 567 ** mean that writes of blocks that are nnn bytes in size and 568 ** are aligned to an address which is an integer multiple of 569 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 570 ** that when data is appended to a file, the data is appended 571 ** first then the size of the file is extended, never the other 572 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 573 ** information is written to disk in the same order as calls 574 ** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that 575 ** after reboot following a crash or power loss, the only bytes in a 576 ** file that were written at the application level might have changed 577 ** and that adjacent bytes, even bytes within the same sector are 578 ** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 579 ** flag indicates that a file cannot be deleted when open. The 580 ** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on 581 ** read-only media and cannot be changed even by processes with 582 ** elevated privileges. 583 */ 584 #define SQLITE_IOCAP_ATOMIC 0x00000001 585 #define SQLITE_IOCAP_ATOMIC512 0x00000002 586 #define SQLITE_IOCAP_ATOMIC1K 0x00000004 587 #define SQLITE_IOCAP_ATOMIC2K 0x00000008 588 #define SQLITE_IOCAP_ATOMIC4K 0x00000010 589 #define SQLITE_IOCAP_ATOMIC8K 0x00000020 590 #define SQLITE_IOCAP_ATOMIC16K 0x00000040 591 #define SQLITE_IOCAP_ATOMIC32K 0x00000080 592 #define SQLITE_IOCAP_ATOMIC64K 0x00000100 593 #define SQLITE_IOCAP_SAFE_APPEND 0x00000200 594 #define SQLITE_IOCAP_SEQUENTIAL 0x00000400 595 #define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 596 #define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000 597 #define SQLITE_IOCAP_IMMUTABLE 0x00002000 598 599 /* 600 ** CAPI3REF: File Locking Levels 601 ** 602 ** SQLite uses one of these integer values as the second 603 ** argument to calls it makes to the xLock() and xUnlock() methods 604 ** of an [sqlite3_io_methods] object. 605 */ 606 #define SQLITE_LOCK_NONE 0 607 #define SQLITE_LOCK_SHARED 1 608 #define SQLITE_LOCK_RESERVED 2 609 #define SQLITE_LOCK_PENDING 3 610 #define SQLITE_LOCK_EXCLUSIVE 4 611 612 /* 613 ** CAPI3REF: Synchronization Type Flags 614 ** 615 ** When SQLite invokes the xSync() method of an 616 ** [sqlite3_io_methods] object it uses a combination of 617 ** these integer values as the second argument. 618 ** 619 ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 620 ** sync operation only needs to flush data to mass storage. Inode 621 ** information need not be flushed. If the lower four bits of the flag 622 ** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 623 ** If the lower four bits equal SQLITE_SYNC_FULL, that means 624 ** to use Mac OS X style fullsync instead of fsync(). 625 ** 626 ** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags 627 ** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL 628 ** settings. The [synchronous pragma] determines when calls to the 629 ** xSync VFS method occur and applies uniformly across all platforms. 630 ** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how 631 ** energetic or rigorous or forceful the sync operations are and 632 ** only make a difference on Mac OSX for the default SQLite code. 633 ** (Third-party VFS implementations might also make the distinction 634 ** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the 635 ** operating systems natively supported by SQLite, only Mac OSX 636 ** cares about the difference.) 637 */ 638 #define SQLITE_SYNC_NORMAL 0x00002 639 #define SQLITE_SYNC_FULL 0x00003 640 #define SQLITE_SYNC_DATAONLY 0x00010 641 642 /* 643 ** CAPI3REF: OS Interface Open File Handle 644 ** 645 ** An [sqlite3_file] object represents an open file in the 646 ** [sqlite3_vfs | OS interface layer]. Individual OS interface 647 ** implementations will 648 ** want to subclass this object by appending additional fields 649 ** for their own use. The pMethods entry is a pointer to an 650 ** [sqlite3_io_methods] object that defines methods for performing 651 ** I/O operations on the open file. 652 */ 653 typedef struct sqlite3_file sqlite3_file; 654 struct sqlite3_file { 655 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 656 }; 657 658 /* 659 ** CAPI3REF: OS Interface File Virtual Methods Object 660 ** 661 ** Every file opened by the [sqlite3_vfs.xOpen] method populates an 662 ** [sqlite3_file] object (or, more commonly, a subclass of the 663 ** [sqlite3_file] object) with a pointer to an instance of this object. 664 ** This object defines the methods used to perform various operations 665 ** against the open file represented by the [sqlite3_file] object. 666 ** 667 ** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 668 ** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 669 ** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The 670 ** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen] 671 ** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element 672 ** to NULL. 673 ** 674 ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 675 ** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 676 ** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 677 ** flag may be ORed in to indicate that only the data of the file 678 ** and not its inode needs to be synced. 679 ** 680 ** The integer values to xLock() and xUnlock() are one of 681 ** <ul> 682 ** <li> [SQLITE_LOCK_NONE], 683 ** <li> [SQLITE_LOCK_SHARED], 684 ** <li> [SQLITE_LOCK_RESERVED], 685 ** <li> [SQLITE_LOCK_PENDING], or 686 ** <li> [SQLITE_LOCK_EXCLUSIVE]. 687 ** </ul> 688 ** xLock() increases the lock. xUnlock() decreases the lock. 689 ** The xCheckReservedLock() method checks whether any database connection, 690 ** either in this process or in some other process, is holding a RESERVED, 691 ** PENDING, or EXCLUSIVE lock on the file. It returns true 692 ** if such a lock exists and false otherwise. 693 ** 694 ** The xFileControl() method is a generic interface that allows custom 695 ** VFS implementations to directly control an open file using the 696 ** [sqlite3_file_control()] interface. The second "op" argument is an 697 ** integer opcode. The third argument is a generic pointer intended to 698 ** point to a structure that may contain arguments or space in which to 699 ** write return values. Potential uses for xFileControl() might be 700 ** functions to enable blocking locks with timeouts, to change the 701 ** locking strategy (for example to use dot-file locks), to inquire 702 ** about the status of a lock, or to break stale locks. The SQLite 703 ** core reserves all opcodes less than 100 for its own use. 704 ** A [file control opcodes | list of opcodes] less than 100 is available. 705 ** Applications that define a custom xFileControl method should use opcodes 706 ** greater than 100 to avoid conflicts. VFS implementations should 707 ** return [SQLITE_NOTFOUND] for file control opcodes that they do not 708 ** recognize. 709 ** 710 ** The xSectorSize() method returns the sector size of the 711 ** device that underlies the file. The sector size is the 712 ** minimum write that can be performed without disturbing 713 ** other bytes in the file. The xDeviceCharacteristics() 714 ** method returns a bit vector describing behaviors of the 715 ** underlying device: 716 ** 717 ** <ul> 718 ** <li> [SQLITE_IOCAP_ATOMIC] 719 ** <li> [SQLITE_IOCAP_ATOMIC512] 720 ** <li> [SQLITE_IOCAP_ATOMIC1K] 721 ** <li> [SQLITE_IOCAP_ATOMIC2K] 722 ** <li> [SQLITE_IOCAP_ATOMIC4K] 723 ** <li> [SQLITE_IOCAP_ATOMIC8K] 724 ** <li> [SQLITE_IOCAP_ATOMIC16K] 725 ** <li> [SQLITE_IOCAP_ATOMIC32K] 726 ** <li> [SQLITE_IOCAP_ATOMIC64K] 727 ** <li> [SQLITE_IOCAP_SAFE_APPEND] 728 ** <li> [SQLITE_IOCAP_SEQUENTIAL] 729 ** <li> [SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN] 730 ** <li> [SQLITE_IOCAP_POWERSAFE_OVERWRITE] 731 ** <li> [SQLITE_IOCAP_IMMUTABLE] 732 ** </ul> 733 ** 734 ** The SQLITE_IOCAP_ATOMIC property means that all writes of 735 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 736 ** mean that writes of blocks that are nnn bytes in size and 737 ** are aligned to an address which is an integer multiple of 738 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 739 ** that when data is appended to a file, the data is appended 740 ** first then the size of the file is extended, never the other 741 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 742 ** information is written to disk in the same order as calls 743 ** to xWrite(). 744 ** 745 ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 746 ** in the unread portions of the buffer with zeros. A VFS that 747 ** fails to zero-fill short reads might seem to work. However, 748 ** failure to zero-fill short reads will eventually lead to 749 ** database corruption. 750 */ 751 typedef struct sqlite3_io_methods sqlite3_io_methods; 752 struct sqlite3_io_methods { 753 int iVersion; 754 int (*xClose)(sqlite3_file*); 755 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 756 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 757 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 758 int (*xSync)(sqlite3_file*, int flags); 759 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 760 int (*xLock)(sqlite3_file*, int); 761 int (*xUnlock)(sqlite3_file*, int); 762 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 763 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 764 int (*xSectorSize)(sqlite3_file*); 765 int (*xDeviceCharacteristics)(sqlite3_file*); 766 /* Methods above are valid for version 1 */ 767 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 768 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 769 void (*xShmBarrier)(sqlite3_file*); 770 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); 771 /* Methods above are valid for version 2 */ 772 int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp); 773 int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p); 774 /* Methods above are valid for version 3 */ 775 /* Additional methods may be added in future releases */ 776 }; 777 778 /* 779 ** CAPI3REF: Standard File Control Opcodes 780 ** KEYWORDS: {file control opcodes} {file control opcode} 781 ** 782 ** These integer constants are opcodes for the xFileControl method 783 ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 784 ** interface. 785 ** 786 ** <ul> 787 ** <li>[[SQLITE_FCNTL_LOCKSTATE]] 788 ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 789 ** opcode causes the xFileControl method to write the current state of 790 ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 791 ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 792 ** into an integer that the pArg argument points to. This capability 793 ** is used during testing and is only available when the SQLITE_TEST 794 ** compile-time option is used. 795 ** 796 ** <li>[[SQLITE_FCNTL_SIZE_HINT]] 797 ** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 798 ** layer a hint of how large the database file will grow to be during the 799 ** current transaction. This hint is not guaranteed to be accurate but it 800 ** is often close. The underlying VFS might choose to preallocate database 801 ** file space based on this hint in order to help writes to the database 802 ** file run faster. 803 ** 804 ** <li>[[SQLITE_FCNTL_CHUNK_SIZE]] 805 ** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 806 ** extends and truncates the database file in chunks of a size specified 807 ** by the user. The fourth argument to [sqlite3_file_control()] should 808 ** point to an integer (type int) containing the new chunk-size to use 809 ** for the nominated database. Allocating database file space in large 810 ** chunks (say 1MB at a time), may reduce file-system fragmentation and 811 ** improve performance on some systems. 812 ** 813 ** <li>[[SQLITE_FCNTL_FILE_POINTER]] 814 ** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer 815 ** to the [sqlite3_file] object associated with a particular database 816 ** connection. See also [SQLITE_FCNTL_JOURNAL_POINTER]. 817 ** 818 ** <li>[[SQLITE_FCNTL_JOURNAL_POINTER]] 819 ** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer 820 ** to the [sqlite3_file] object associated with the journal file (either 821 ** the [rollback journal] or the [write-ahead log]) for a particular database 822 ** connection. See also [SQLITE_FCNTL_FILE_POINTER]. 823 ** 824 ** <li>[[SQLITE_FCNTL_SYNC_OMITTED]] 825 ** No longer in use. 826 ** 827 ** <li>[[SQLITE_FCNTL_SYNC]] 828 ** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and 829 ** sent to the VFS immediately before the xSync method is invoked on a 830 ** database file descriptor. Or, if the xSync method is not invoked 831 ** because the user has configured SQLite with 832 ** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place 833 ** of the xSync method. In most cases, the pointer argument passed with 834 ** this file-control is NULL. However, if the database file is being synced 835 ** as part of a multi-database commit, the argument points to a nul-terminated 836 ** string containing the transactions master-journal file name. VFSes that 837 ** do not need this signal should silently ignore this opcode. Applications 838 ** should not call [sqlite3_file_control()] with this opcode as doing so may 839 ** disrupt the operation of the specialized VFSes that do require it. 840 ** 841 ** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]] 842 ** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite 843 ** and sent to the VFS after a transaction has been committed immediately 844 ** but before the database is unlocked. VFSes that do not need this signal 845 ** should silently ignore this opcode. Applications should not call 846 ** [sqlite3_file_control()] with this opcode as doing so may disrupt the 847 ** operation of the specialized VFSes that do require it. 848 ** 849 ** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]] 850 ** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic 851 ** retry counts and intervals for certain disk I/O operations for the 852 ** windows [VFS] in order to provide robustness in the presence of 853 ** anti-virus programs. By default, the windows VFS will retry file read, 854 ** file write, and file delete operations up to 10 times, with a delay 855 ** of 25 milliseconds before the first retry and with the delay increasing 856 ** by an additional 25 milliseconds with each subsequent retry. This 857 ** opcode allows these two values (10 retries and 25 milliseconds of delay) 858 ** to be adjusted. The values are changed for all database connections 859 ** within the same process. The argument is a pointer to an array of two 860 ** integers where the first integer is the new retry count and the second 861 ** integer is the delay. If either integer is negative, then the setting 862 ** is not changed but instead the prior value of that setting is written 863 ** into the array entry, allowing the current retry settings to be 864 ** interrogated. The zDbName parameter is ignored. 865 ** 866 ** <li>[[SQLITE_FCNTL_PERSIST_WAL]] 867 ** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the 868 ** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary 869 ** write ahead log and shared memory files used for transaction control 870 ** are automatically deleted when the latest connection to the database 871 ** closes. Setting persistent WAL mode causes those files to persist after 872 ** close. Persisting the files is useful when other processes that do not 873 ** have write permission on the directory containing the database file want 874 ** to read the database file, as the WAL and shared memory files must exist 875 ** in order for the database to be readable. The fourth parameter to 876 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 877 ** That integer is 0 to disable persistent WAL mode or 1 to enable persistent 878 ** WAL mode. If the integer is -1, then it is overwritten with the current 879 ** WAL persistence setting. 880 ** 881 ** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]] 882 ** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the 883 ** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting 884 ** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the 885 ** xDeviceCharacteristics methods. The fourth parameter to 886 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 887 ** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage 888 ** mode. If the integer is -1, then it is overwritten with the current 889 ** zero-damage mode setting. 890 ** 891 ** <li>[[SQLITE_FCNTL_OVERWRITE]] 892 ** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening 893 ** a write transaction to indicate that, unless it is rolled back for some 894 ** reason, the entire database file will be overwritten by the current 895 ** transaction. This is used by VACUUM operations. 896 ** 897 ** <li>[[SQLITE_FCNTL_VFSNAME]] 898 ** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of 899 ** all [VFSes] in the VFS stack. The names are of all VFS shims and the 900 ** final bottom-level VFS are written into memory obtained from 901 ** [sqlite3_malloc()] and the result is stored in the char* variable 902 ** that the fourth parameter of [sqlite3_file_control()] points to. 903 ** The caller is responsible for freeing the memory when done. As with 904 ** all file-control actions, there is no guarantee that this will actually 905 ** do anything. Callers should initialize the char* variable to a NULL 906 ** pointer in case this file-control is not implemented. This file-control 907 ** is intended for diagnostic use only. 908 ** 909 ** <li>[[SQLITE_FCNTL_VFS_POINTER]] 910 ** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level 911 ** [VFSes] currently in use. ^(The argument X in 912 ** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be 913 ** of type "[sqlite3_vfs] **". This opcodes will set *X 914 ** to a pointer to the top-level VFS.)^ 915 ** ^When there are multiple VFS shims in the stack, this opcode finds the 916 ** upper-most shim only. 917 ** 918 ** <li>[[SQLITE_FCNTL_PRAGMA]] 919 ** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA] 920 ** file control is sent to the open [sqlite3_file] object corresponding 921 ** to the database file to which the pragma statement refers. ^The argument 922 ** to the [SQLITE_FCNTL_PRAGMA] file control is an array of 923 ** pointers to strings (char**) in which the second element of the array 924 ** is the name of the pragma and the third element is the argument to the 925 ** pragma or NULL if the pragma has no argument. ^The handler for an 926 ** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element 927 ** of the char** argument point to a string obtained from [sqlite3_mprintf()] 928 ** or the equivalent and that string will become the result of the pragma or 929 ** the error message if the pragma fails. ^If the 930 ** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal 931 ** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA] 932 ** file control returns [SQLITE_OK], then the parser assumes that the 933 ** VFS has handled the PRAGMA itself and the parser generates a no-op 934 ** prepared statement if result string is NULL, or that returns a copy 935 ** of the result string if the string is non-NULL. 936 ** ^If the [SQLITE_FCNTL_PRAGMA] file control returns 937 ** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means 938 ** that the VFS encountered an error while handling the [PRAGMA] and the 939 ** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA] 940 ** file control occurs at the beginning of pragma statement analysis and so 941 ** it is able to override built-in [PRAGMA] statements. 942 ** 943 ** <li>[[SQLITE_FCNTL_BUSYHANDLER]] 944 ** ^The [SQLITE_FCNTL_BUSYHANDLER] 945 ** file-control may be invoked by SQLite on the database file handle 946 ** shortly after it is opened in order to provide a custom VFS with access 947 ** to the connections busy-handler callback. The argument is of type (void **) 948 ** - an array of two (void *) values. The first (void *) actually points 949 ** to a function of type (int (*)(void *)). In order to invoke the connections 950 ** busy-handler, this function should be invoked with the second (void *) in 951 ** the array as the only argument. If it returns non-zero, then the operation 952 ** should be retried. If it returns zero, the custom VFS should abandon the 953 ** current operation. 954 ** 955 ** <li>[[SQLITE_FCNTL_TEMPFILENAME]] 956 ** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control 957 ** to have SQLite generate a 958 ** temporary filename using the same algorithm that is followed to generate 959 ** temporary filenames for TEMP tables and other internal uses. The 960 ** argument should be a char** which will be filled with the filename 961 ** written into memory obtained from [sqlite3_malloc()]. The caller should 962 ** invoke [sqlite3_free()] on the result to avoid a memory leak. 963 ** 964 ** <li>[[SQLITE_FCNTL_MMAP_SIZE]] 965 ** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the 966 ** maximum number of bytes that will be used for memory-mapped I/O. 967 ** The argument is a pointer to a value of type sqlite3_int64 that 968 ** is an advisory maximum number of bytes in the file to memory map. The 969 ** pointer is overwritten with the old value. The limit is not changed if 970 ** the value originally pointed to is negative, and so the current limit 971 ** can be queried by passing in a pointer to a negative number. This 972 ** file-control is used internally to implement [PRAGMA mmap_size]. 973 ** 974 ** <li>[[SQLITE_FCNTL_TRACE]] 975 ** The [SQLITE_FCNTL_TRACE] file control provides advisory information 976 ** to the VFS about what the higher layers of the SQLite stack are doing. 977 ** This file control is used by some VFS activity tracing [shims]. 978 ** The argument is a zero-terminated string. Higher layers in the 979 ** SQLite stack may generate instances of this file control if 980 ** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled. 981 ** 982 ** <li>[[SQLITE_FCNTL_HAS_MOVED]] 983 ** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a 984 ** pointer to an integer and it writes a boolean into that integer depending 985 ** on whether or not the file has been renamed, moved, or deleted since it 986 ** was first opened. 987 ** 988 ** <li>[[SQLITE_FCNTL_WIN32_GET_HANDLE]] 989 ** The [SQLITE_FCNTL_WIN32_GET_HANDLE] opcode can be used to obtain the 990 ** underlying native file handle associated with a file handle. This file 991 ** control interprets its argument as a pointer to a native file handle and 992 ** writes the resulting value there. 993 ** 994 ** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]] 995 ** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This 996 ** opcode causes the xFileControl method to swap the file handle with the one 997 ** pointed to by the pArg argument. This capability is used during testing 998 ** and only needs to be supported when SQLITE_TEST is defined. 999 ** 1000 ** <li>[[SQLITE_FCNTL_WAL_BLOCK]] 1001 ** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might 1002 ** be advantageous to block on the next WAL lock if the lock is not immediately 1003 ** available. The WAL subsystem issues this signal during rare 1004 ** circumstances in order to fix a problem with priority inversion. 1005 ** Applications should <em>not</em> use this file-control. 1006 ** 1007 ** <li>[[SQLITE_FCNTL_ZIPVFS]] 1008 ** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other 1009 ** VFS should return SQLITE_NOTFOUND for this opcode. 1010 ** 1011 ** <li>[[SQLITE_FCNTL_RBU]] 1012 ** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by 1013 ** the RBU extension only. All other VFS should return SQLITE_NOTFOUND for 1014 ** this opcode. 1015 ** </ul> 1016 */ 1017 #define SQLITE_FCNTL_LOCKSTATE 1 1018 #define SQLITE_FCNTL_GET_LOCKPROXYFILE 2 1019 #define SQLITE_FCNTL_SET_LOCKPROXYFILE 3 1020 #define SQLITE_FCNTL_LAST_ERRNO 4 1021 #define SQLITE_FCNTL_SIZE_HINT 5 1022 #define SQLITE_FCNTL_CHUNK_SIZE 6 1023 #define SQLITE_FCNTL_FILE_POINTER 7 1024 #define SQLITE_FCNTL_SYNC_OMITTED 8 1025 #define SQLITE_FCNTL_WIN32_AV_RETRY 9 1026 #define SQLITE_FCNTL_PERSIST_WAL 10 1027 #define SQLITE_FCNTL_OVERWRITE 11 1028 #define SQLITE_FCNTL_VFSNAME 12 1029 #define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13 1030 #define SQLITE_FCNTL_PRAGMA 14 1031 #define SQLITE_FCNTL_BUSYHANDLER 15 1032 #define SQLITE_FCNTL_TEMPFILENAME 16 1033 #define SQLITE_FCNTL_MMAP_SIZE 18 1034 #define SQLITE_FCNTL_TRACE 19 1035 #define SQLITE_FCNTL_HAS_MOVED 20 1036 #define SQLITE_FCNTL_SYNC 21 1037 #define SQLITE_FCNTL_COMMIT_PHASETWO 22 1038 #define SQLITE_FCNTL_WIN32_SET_HANDLE 23 1039 #define SQLITE_FCNTL_WAL_BLOCK 24 1040 #define SQLITE_FCNTL_ZIPVFS 25 1041 #define SQLITE_FCNTL_RBU 26 1042 #define SQLITE_FCNTL_VFS_POINTER 27 1043 #define SQLITE_FCNTL_JOURNAL_POINTER 28 1044 #define SQLITE_FCNTL_WIN32_GET_HANDLE 29 1045 #define SQLITE_FCNTL_PDB 30 1046 1047 /* deprecated names */ 1048 #define SQLITE_GET_LOCKPROXYFILE SQLITE_FCNTL_GET_LOCKPROXYFILE 1049 #define SQLITE_SET_LOCKPROXYFILE SQLITE_FCNTL_SET_LOCKPROXYFILE 1050 #define SQLITE_LAST_ERRNO SQLITE_FCNTL_LAST_ERRNO 1051 1052 1053 /* 1054 ** CAPI3REF: Mutex Handle 1055 ** 1056 ** The mutex module within SQLite defines [sqlite3_mutex] to be an 1057 ** abstract type for a mutex object. The SQLite core never looks 1058 ** at the internal representation of an [sqlite3_mutex]. It only 1059 ** deals with pointers to the [sqlite3_mutex] object. 1060 ** 1061 ** Mutexes are created using [sqlite3_mutex_alloc()]. 1062 */ 1063 typedef struct sqlite3_mutex sqlite3_mutex; 1064 1065 /* 1066 ** CAPI3REF: Loadable Extension Thunk 1067 ** 1068 ** A pointer to the opaque sqlite3_api_routines structure is passed as 1069 ** the third parameter to entry points of [loadable extensions]. This 1070 ** structure must be typedefed in order to work around compiler warnings 1071 ** on some platforms. 1072 */ 1073 typedef struct sqlite3_api_routines sqlite3_api_routines; 1074 1075 /* 1076 ** CAPI3REF: OS Interface Object 1077 ** 1078 ** An instance of the sqlite3_vfs object defines the interface between 1079 ** the SQLite core and the underlying operating system. The "vfs" 1080 ** in the name of the object stands for "virtual file system". See 1081 ** the [VFS | VFS documentation] for further information. 1082 ** 1083 ** The value of the iVersion field is initially 1 but may be larger in 1084 ** future versions of SQLite. Additional fields may be appended to this 1085 ** object when the iVersion value is increased. Note that the structure 1086 ** of the sqlite3_vfs object changes in the transaction between 1087 ** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 1088 ** modified. 1089 ** 1090 ** The szOsFile field is the size of the subclassed [sqlite3_file] 1091 ** structure used by this VFS. mxPathname is the maximum length of 1092 ** a pathname in this VFS. 1093 ** 1094 ** Registered sqlite3_vfs objects are kept on a linked list formed by 1095 ** the pNext pointer. The [sqlite3_vfs_register()] 1096 ** and [sqlite3_vfs_unregister()] interfaces manage this list 1097 ** in a thread-safe way. The [sqlite3_vfs_find()] interface 1098 ** searches the list. Neither the application code nor the VFS 1099 ** implementation should use the pNext pointer. 1100 ** 1101 ** The pNext field is the only field in the sqlite3_vfs 1102 ** structure that SQLite will ever modify. SQLite will only access 1103 ** or modify this field while holding a particular static mutex. 1104 ** The application should never modify anything within the sqlite3_vfs 1105 ** object once the object has been registered. 1106 ** 1107 ** The zName field holds the name of the VFS module. The name must 1108 ** be unique across all VFS modules. 1109 ** 1110 ** [[sqlite3_vfs.xOpen]] 1111 ** ^SQLite guarantees that the zFilename parameter to xOpen 1112 ** is either a NULL pointer or string obtained 1113 ** from xFullPathname() with an optional suffix added. 1114 ** ^If a suffix is added to the zFilename parameter, it will 1115 ** consist of a single "-" character followed by no more than 1116 ** 11 alphanumeric and/or "-" characters. 1117 ** ^SQLite further guarantees that 1118 ** the string will be valid and unchanged until xClose() is 1119 ** called. Because of the previous sentence, 1120 ** the [sqlite3_file] can safely store a pointer to the 1121 ** filename if it needs to remember the filename for some reason. 1122 ** If the zFilename parameter to xOpen is a NULL pointer then xOpen 1123 ** must invent its own temporary name for the file. ^Whenever the 1124 ** xFilename parameter is NULL it will also be the case that the 1125 ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 1126 ** 1127 ** The flags argument to xOpen() includes all bits set in 1128 ** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 1129 ** or [sqlite3_open16()] is used, then flags includes at least 1130 ** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 1131 ** If xOpen() opens a file read-only then it sets *pOutFlags to 1132 ** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 1133 ** 1134 ** ^(SQLite will also add one of the following flags to the xOpen() 1135 ** call, depending on the object being opened: 1136 ** 1137 ** <ul> 1138 ** <li> [SQLITE_OPEN_MAIN_DB] 1139 ** <li> [SQLITE_OPEN_MAIN_JOURNAL] 1140 ** <li> [SQLITE_OPEN_TEMP_DB] 1141 ** <li> [SQLITE_OPEN_TEMP_JOURNAL] 1142 ** <li> [SQLITE_OPEN_TRANSIENT_DB] 1143 ** <li> [SQLITE_OPEN_SUBJOURNAL] 1144 ** <li> [SQLITE_OPEN_MASTER_JOURNAL] 1145 ** <li> [SQLITE_OPEN_WAL] 1146 ** </ul>)^ 1147 ** 1148 ** The file I/O implementation can use the object type flags to 1149 ** change the way it deals with files. For example, an application 1150 ** that does not care about crash recovery or rollback might make 1151 ** the open of a journal file a no-op. Writes to this journal would 1152 ** also be no-ops, and any attempt to read the journal would return 1153 ** SQLITE_IOERR. Or the implementation might recognize that a database 1154 ** file will be doing page-aligned sector reads and writes in a random 1155 ** order and set up its I/O subsystem accordingly. 1156 ** 1157 ** SQLite might also add one of the following flags to the xOpen method: 1158 ** 1159 ** <ul> 1160 ** <li> [SQLITE_OPEN_DELETEONCLOSE] 1161 ** <li> [SQLITE_OPEN_EXCLUSIVE] 1162 ** </ul> 1163 ** 1164 ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 1165 ** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 1166 ** will be set for TEMP databases and their journals, transient 1167 ** databases, and subjournals. 1168 ** 1169 ** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 1170 ** with the [SQLITE_OPEN_CREATE] flag, which are both directly 1171 ** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 1172 ** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 1173 ** SQLITE_OPEN_CREATE, is used to indicate that file should always 1174 ** be created, and that it is an error if it already exists. 1175 ** It is <i>not</i> used to indicate the file should be opened 1176 ** for exclusive access. 1177 ** 1178 ** ^At least szOsFile bytes of memory are allocated by SQLite 1179 ** to hold the [sqlite3_file] structure passed as the third 1180 ** argument to xOpen. The xOpen method does not have to 1181 ** allocate the structure; it should just fill it in. Note that 1182 ** the xOpen method must set the sqlite3_file.pMethods to either 1183 ** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 1184 ** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 1185 ** element will be valid after xOpen returns regardless of the success 1186 ** or failure of the xOpen call. 1187 ** 1188 ** [[sqlite3_vfs.xAccess]] 1189 ** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 1190 ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 1191 ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 1192 ** to test whether a file is at least readable. The file can be a 1193 ** directory. 1194 ** 1195 ** ^SQLite will always allocate at least mxPathname+1 bytes for the 1196 ** output buffer xFullPathname. The exact size of the output buffer 1197 ** is also passed as a parameter to both methods. If the output buffer 1198 ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 1199 ** handled as a fatal error by SQLite, vfs implementations should endeavor 1200 ** to prevent this by setting mxPathname to a sufficiently large value. 1201 ** 1202 ** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 1203 ** interfaces are not strictly a part of the filesystem, but they are 1204 ** included in the VFS structure for completeness. 1205 ** The xRandomness() function attempts to return nBytes bytes 1206 ** of good-quality randomness into zOut. The return value is 1207 ** the actual number of bytes of randomness obtained. 1208 ** The xSleep() method causes the calling thread to sleep for at 1209 ** least the number of microseconds given. ^The xCurrentTime() 1210 ** method returns a Julian Day Number for the current date and time as 1211 ** a floating point value. 1212 ** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 1213 ** Day Number multiplied by 86400000 (the number of milliseconds in 1214 ** a 24-hour day). 1215 ** ^SQLite will use the xCurrentTimeInt64() method to get the current 1216 ** date and time if that method is available (if iVersion is 2 or 1217 ** greater and the function pointer is not NULL) and will fall back 1218 ** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 1219 ** 1220 ** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 1221 ** are not used by the SQLite core. These optional interfaces are provided 1222 ** by some VFSes to facilitate testing of the VFS code. By overriding 1223 ** system calls with functions under its control, a test program can 1224 ** simulate faults and error conditions that would otherwise be difficult 1225 ** or impossible to induce. The set of system calls that can be overridden 1226 ** varies from one VFS to another, and from one version of the same VFS to the 1227 ** next. Applications that use these interfaces must be prepared for any 1228 ** or all of these interfaces to be NULL or for their behavior to change 1229 ** from one release to the next. Applications must not attempt to access 1230 ** any of these methods if the iVersion of the VFS is less than 3. 1231 */ 1232 typedef struct sqlite3_vfs sqlite3_vfs; 1233 typedef void (*sqlite3_syscall_ptr)(void); 1234 struct sqlite3_vfs { 1235 int iVersion; /* Structure version number (currently 3) */ 1236 int szOsFile; /* Size of subclassed sqlite3_file */ 1237 int mxPathname; /* Maximum file pathname length */ 1238 sqlite3_vfs *pNext; /* Next registered VFS */ 1239 const char *zName; /* Name of this virtual file system */ 1240 void *pAppData; /* Pointer to application-specific data */ 1241 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 1242 int flags, int *pOutFlags); 1243 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 1244 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 1245 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 1246 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 1247 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 1248 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 1249 void (*xDlClose)(sqlite3_vfs*, void*); 1250 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 1251 int (*xSleep)(sqlite3_vfs*, int microseconds); 1252 int (*xCurrentTime)(sqlite3_vfs*, double*); 1253 int (*xGetLastError)(sqlite3_vfs*, int, char *); 1254 /* 1255 ** The methods above are in version 1 of the sqlite_vfs object 1256 ** definition. Those that follow are added in version 2 or later 1257 */ 1258 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 1259 /* 1260 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 1261 ** Those below are for version 3 and greater. 1262 */ 1263 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 1264 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 1265 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 1266 /* 1267 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 1268 ** New fields may be appended in future versions. The iVersion 1269 ** value will increment whenever this happens. 1270 */ 1271 }; 1272 1273 /* 1274 ** CAPI3REF: Flags for the xAccess VFS method 1275 ** 1276 ** These integer constants can be used as the third parameter to 1277 ** the xAccess method of an [sqlite3_vfs] object. They determine 1278 ** what kind of permissions the xAccess method is looking for. 1279 ** With SQLITE_ACCESS_EXISTS, the xAccess method 1280 ** simply checks whether the file exists. 1281 ** With SQLITE_ACCESS_READWRITE, the xAccess method 1282 ** checks whether the named directory is both readable and writable 1283 ** (in other words, if files can be added, removed, and renamed within 1284 ** the directory). 1285 ** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1286 ** [temp_store_directory pragma], though this could change in a future 1287 ** release of SQLite. 1288 ** With SQLITE_ACCESS_READ, the xAccess method 1289 ** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1290 ** currently unused, though it might be used in a future release of 1291 ** SQLite. 1292 */ 1293 #define SQLITE_ACCESS_EXISTS 0 1294 #define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1295 #define SQLITE_ACCESS_READ 2 /* Unused */ 1296 1297 /* 1298 ** CAPI3REF: Flags for the xShmLock VFS method 1299 ** 1300 ** These integer constants define the various locking operations 1301 ** allowed by the xShmLock method of [sqlite3_io_methods]. The 1302 ** following are the only legal combinations of flags to the 1303 ** xShmLock method: 1304 ** 1305 ** <ul> 1306 ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1307 ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1308 ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1309 ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1310 ** </ul> 1311 ** 1312 ** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1313 ** was given on the corresponding lock. 1314 ** 1315 ** The xShmLock method can transition between unlocked and SHARED or 1316 ** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1317 ** and EXCLUSIVE. 1318 */ 1319 #define SQLITE_SHM_UNLOCK 1 1320 #define SQLITE_SHM_LOCK 2 1321 #define SQLITE_SHM_SHARED 4 1322 #define SQLITE_SHM_EXCLUSIVE 8 1323 1324 /* 1325 ** CAPI3REF: Maximum xShmLock index 1326 ** 1327 ** The xShmLock method on [sqlite3_io_methods] may use values 1328 ** between 0 and this upper bound as its "offset" argument. 1329 ** The SQLite core will never attempt to acquire or release a 1330 ** lock outside of this range 1331 */ 1332 #define SQLITE_SHM_NLOCK 8 1333 1334 1335 /* 1336 ** CAPI3REF: Initialize The SQLite Library 1337 ** 1338 ** ^The sqlite3_initialize() routine initializes the 1339 ** SQLite library. ^The sqlite3_shutdown() routine 1340 ** deallocates any resources that were allocated by sqlite3_initialize(). 1341 ** These routines are designed to aid in process initialization and 1342 ** shutdown on embedded systems. Workstation applications using 1343 ** SQLite normally do not need to invoke either of these routines. 1344 ** 1345 ** A call to sqlite3_initialize() is an "effective" call if it is 1346 ** the first time sqlite3_initialize() is invoked during the lifetime of 1347 ** the process, or if it is the first time sqlite3_initialize() is invoked 1348 ** following a call to sqlite3_shutdown(). ^(Only an effective call 1349 ** of sqlite3_initialize() does any initialization. All other calls 1350 ** are harmless no-ops.)^ 1351 ** 1352 ** A call to sqlite3_shutdown() is an "effective" call if it is the first 1353 ** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1354 ** an effective call to sqlite3_shutdown() does any deinitialization. 1355 ** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1356 ** 1357 ** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1358 ** is not. The sqlite3_shutdown() interface must only be called from a 1359 ** single thread. All open [database connections] must be closed and all 1360 ** other SQLite resources must be deallocated prior to invoking 1361 ** sqlite3_shutdown(). 1362 ** 1363 ** Among other things, ^sqlite3_initialize() will invoke 1364 ** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1365 ** will invoke sqlite3_os_end(). 1366 ** 1367 ** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1368 ** ^If for some reason, sqlite3_initialize() is unable to initialize 1369 ** the library (perhaps it is unable to allocate a needed resource such 1370 ** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1371 ** 1372 ** ^The sqlite3_initialize() routine is called internally by many other 1373 ** SQLite interfaces so that an application usually does not need to 1374 ** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1375 ** calls sqlite3_initialize() so the SQLite library will be automatically 1376 ** initialized when [sqlite3_open()] is called if it has not be initialized 1377 ** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1378 ** compile-time option, then the automatic calls to sqlite3_initialize() 1379 ** are omitted and the application must call sqlite3_initialize() directly 1380 ** prior to using any other SQLite interface. For maximum portability, 1381 ** it is recommended that applications always invoke sqlite3_initialize() 1382 ** directly prior to using any other SQLite interface. Future releases 1383 ** of SQLite may require this. In other words, the behavior exhibited 1384 ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1385 ** default behavior in some future release of SQLite. 1386 ** 1387 ** The sqlite3_os_init() routine does operating-system specific 1388 ** initialization of the SQLite library. The sqlite3_os_end() 1389 ** routine undoes the effect of sqlite3_os_init(). Typical tasks 1390 ** performed by these routines include allocation or deallocation 1391 ** of static resources, initialization of global variables, 1392 ** setting up a default [sqlite3_vfs] module, or setting up 1393 ** a default configuration using [sqlite3_config()]. 1394 ** 1395 ** The application should never invoke either sqlite3_os_init() 1396 ** or sqlite3_os_end() directly. The application should only invoke 1397 ** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1398 ** interface is called automatically by sqlite3_initialize() and 1399 ** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1400 ** implementations for sqlite3_os_init() and sqlite3_os_end() 1401 ** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1402 ** When [custom builds | built for other platforms] 1403 ** (using the [SQLITE_OS_OTHER=1] compile-time 1404 ** option) the application must supply a suitable implementation for 1405 ** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1406 ** implementation of sqlite3_os_init() or sqlite3_os_end() 1407 ** must return [SQLITE_OK] on success and some other [error code] upon 1408 ** failure. 1409 */ 1410 SQLITE_API int sqlite3_initialize(void); 1411 SQLITE_API int sqlite3_shutdown(void); 1412 SQLITE_API int sqlite3_os_init(void); 1413 SQLITE_API int sqlite3_os_end(void); 1414 1415 /* 1416 ** CAPI3REF: Configuring The SQLite Library 1417 ** 1418 ** The sqlite3_config() interface is used to make global configuration 1419 ** changes to SQLite in order to tune SQLite to the specific needs of 1420 ** the application. The default configuration is recommended for most 1421 ** applications and so this routine is usually not necessary. It is 1422 ** provided to support rare applications with unusual needs. 1423 ** 1424 ** <b>The sqlite3_config() interface is not threadsafe. The application 1425 ** must ensure that no other SQLite interfaces are invoked by other 1426 ** threads while sqlite3_config() is running.</b> 1427 ** 1428 ** The sqlite3_config() interface 1429 ** may only be invoked prior to library initialization using 1430 ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1431 ** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1432 ** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1433 ** Note, however, that ^sqlite3_config() can be called as part of the 1434 ** implementation of an application-defined [sqlite3_os_init()]. 1435 ** 1436 ** The first argument to sqlite3_config() is an integer 1437 ** [configuration option] that determines 1438 ** what property of SQLite is to be configured. Subsequent arguments 1439 ** vary depending on the [configuration option] 1440 ** in the first argument. 1441 ** 1442 ** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1443 ** ^If the option is unknown or SQLite is unable to set the option 1444 ** then this routine returns a non-zero [error code]. 1445 */ 1446 SQLITE_API int sqlite3_config(int, ...); 1447 1448 /* 1449 ** CAPI3REF: Configure database connections 1450 ** METHOD: sqlite3 1451 ** 1452 ** The sqlite3_db_config() interface is used to make configuration 1453 ** changes to a [database connection]. The interface is similar to 1454 ** [sqlite3_config()] except that the changes apply to a single 1455 ** [database connection] (specified in the first argument). 1456 ** 1457 ** The second argument to sqlite3_db_config(D,V,...) is the 1458 ** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1459 ** that indicates what aspect of the [database connection] is being configured. 1460 ** Subsequent arguments vary depending on the configuration verb. 1461 ** 1462 ** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1463 ** the call is considered successful. 1464 */ 1465 SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...); 1466 1467 /* 1468 ** CAPI3REF: Memory Allocation Routines 1469 ** 1470 ** An instance of this object defines the interface between SQLite 1471 ** and low-level memory allocation routines. 1472 ** 1473 ** This object is used in only one place in the SQLite interface. 1474 ** A pointer to an instance of this object is the argument to 1475 ** [sqlite3_config()] when the configuration option is 1476 ** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1477 ** By creating an instance of this object 1478 ** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1479 ** during configuration, an application can specify an alternative 1480 ** memory allocation subsystem for SQLite to use for all of its 1481 ** dynamic memory needs. 1482 ** 1483 ** Note that SQLite comes with several [built-in memory allocators] 1484 ** that are perfectly adequate for the overwhelming majority of applications 1485 ** and that this object is only useful to a tiny minority of applications 1486 ** with specialized memory allocation requirements. This object is 1487 ** also used during testing of SQLite in order to specify an alternative 1488 ** memory allocator that simulates memory out-of-memory conditions in 1489 ** order to verify that SQLite recovers gracefully from such 1490 ** conditions. 1491 ** 1492 ** The xMalloc, xRealloc, and xFree methods must work like the 1493 ** malloc(), realloc() and free() functions from the standard C library. 1494 ** ^SQLite guarantees that the second argument to 1495 ** xRealloc is always a value returned by a prior call to xRoundup. 1496 ** 1497 ** xSize should return the allocated size of a memory allocation 1498 ** previously obtained from xMalloc or xRealloc. The allocated size 1499 ** is always at least as big as the requested size but may be larger. 1500 ** 1501 ** The xRoundup method returns what would be the allocated size of 1502 ** a memory allocation given a particular requested size. Most memory 1503 ** allocators round up memory allocations at least to the next multiple 1504 ** of 8. Some allocators round up to a larger multiple or to a power of 2. 1505 ** Every memory allocation request coming in through [sqlite3_malloc()] 1506 ** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1507 ** that causes the corresponding memory allocation to fail. 1508 ** 1509 ** The xInit method initializes the memory allocator. For example, 1510 ** it might allocate any require mutexes or initialize internal data 1511 ** structures. The xShutdown method is invoked (indirectly) by 1512 ** [sqlite3_shutdown()] and should deallocate any resources acquired 1513 ** by xInit. The pAppData pointer is used as the only parameter to 1514 ** xInit and xShutdown. 1515 ** 1516 ** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1517 ** the xInit method, so the xInit method need not be threadsafe. The 1518 ** xShutdown method is only called from [sqlite3_shutdown()] so it does 1519 ** not need to be threadsafe either. For all other methods, SQLite 1520 ** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1521 ** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1522 ** it is by default) and so the methods are automatically serialized. 1523 ** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1524 ** methods must be threadsafe or else make their own arrangements for 1525 ** serialization. 1526 ** 1527 ** SQLite will never invoke xInit() more than once without an intervening 1528 ** call to xShutdown(). 1529 */ 1530 typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1531 struct sqlite3_mem_methods { 1532 void *(*xMalloc)(int); /* Memory allocation function */ 1533 void (*xFree)(void*); /* Free a prior allocation */ 1534 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1535 int (*xSize)(void*); /* Return the size of an allocation */ 1536 int (*xRoundup)(int); /* Round up request size to allocation size */ 1537 int (*xInit)(void*); /* Initialize the memory allocator */ 1538 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1539 void *pAppData; /* Argument to xInit() and xShutdown() */ 1540 }; 1541 1542 /* 1543 ** CAPI3REF: Configuration Options 1544 ** KEYWORDS: {configuration option} 1545 ** 1546 ** These constants are the available integer configuration options that 1547 ** can be passed as the first argument to the [sqlite3_config()] interface. 1548 ** 1549 ** New configuration options may be added in future releases of SQLite. 1550 ** Existing configuration options might be discontinued. Applications 1551 ** should check the return code from [sqlite3_config()] to make sure that 1552 ** the call worked. The [sqlite3_config()] interface will return a 1553 ** non-zero [error code] if a discontinued or unsupported configuration option 1554 ** is invoked. 1555 ** 1556 ** <dl> 1557 ** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1558 ** <dd>There are no arguments to this option. ^This option sets the 1559 ** [threading mode] to Single-thread. In other words, it disables 1560 ** all mutexing and puts SQLite into a mode where it can only be used 1561 ** by a single thread. ^If SQLite is compiled with 1562 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1563 ** it is not possible to change the [threading mode] from its default 1564 ** value of Single-thread and so [sqlite3_config()] will return 1565 ** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1566 ** configuration option.</dd> 1567 ** 1568 ** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1569 ** <dd>There are no arguments to this option. ^This option sets the 1570 ** [threading mode] to Multi-thread. In other words, it disables 1571 ** mutexing on [database connection] and [prepared statement] objects. 1572 ** The application is responsible for serializing access to 1573 ** [database connections] and [prepared statements]. But other mutexes 1574 ** are enabled so that SQLite will be safe to use in a multi-threaded 1575 ** environment as long as no two threads attempt to use the same 1576 ** [database connection] at the same time. ^If SQLite is compiled with 1577 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1578 ** it is not possible to set the Multi-thread [threading mode] and 1579 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1580 ** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1581 ** 1582 ** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1583 ** <dd>There are no arguments to this option. ^This option sets the 1584 ** [threading mode] to Serialized. In other words, this option enables 1585 ** all mutexes including the recursive 1586 ** mutexes on [database connection] and [prepared statement] objects. 1587 ** In this mode (which is the default when SQLite is compiled with 1588 ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1589 ** to [database connections] and [prepared statements] so that the 1590 ** application is free to use the same [database connection] or the 1591 ** same [prepared statement] in different threads at the same time. 1592 ** ^If SQLite is compiled with 1593 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1594 ** it is not possible to set the Serialized [threading mode] and 1595 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1596 ** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1597 ** 1598 ** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1599 ** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is 1600 ** a pointer to an instance of the [sqlite3_mem_methods] structure. 1601 ** The argument specifies 1602 ** alternative low-level memory allocation routines to be used in place of 1603 ** the memory allocation routines built into SQLite.)^ ^SQLite makes 1604 ** its own private copy of the content of the [sqlite3_mem_methods] structure 1605 ** before the [sqlite3_config()] call returns.</dd> 1606 ** 1607 ** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1608 ** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which 1609 ** is a pointer to an instance of the [sqlite3_mem_methods] structure. 1610 ** The [sqlite3_mem_methods] 1611 ** structure is filled with the currently defined memory allocation routines.)^ 1612 ** This option can be used to overload the default memory allocation 1613 ** routines with a wrapper that simulations memory allocation failure or 1614 ** tracks memory usage, for example. </dd> 1615 ** 1616 ** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1617 ** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int, 1618 ** interpreted as a boolean, which enables or disables the collection of 1619 ** memory allocation statistics. ^(When memory allocation statistics are 1620 ** disabled, the following SQLite interfaces become non-operational: 1621 ** <ul> 1622 ** <li> [sqlite3_memory_used()] 1623 ** <li> [sqlite3_memory_highwater()] 1624 ** <li> [sqlite3_soft_heap_limit64()] 1625 ** <li> [sqlite3_status64()] 1626 ** </ul>)^ 1627 ** ^Memory allocation statistics are enabled by default unless SQLite is 1628 ** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1629 ** allocation statistics are disabled by default. 1630 ** </dd> 1631 ** 1632 ** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1633 ** <dd> ^The SQLITE_CONFIG_SCRATCH option specifies a static memory buffer 1634 ** that SQLite can use for scratch memory. ^(There are three arguments 1635 ** to SQLITE_CONFIG_SCRATCH: A pointer an 8-byte 1636 ** aligned memory buffer from which the scratch allocations will be 1637 ** drawn, the size of each scratch allocation (sz), 1638 ** and the maximum number of scratch allocations (N).)^ 1639 ** The first argument must be a pointer to an 8-byte aligned buffer 1640 ** of at least sz*N bytes of memory. 1641 ** ^SQLite will not use more than one scratch buffers per thread. 1642 ** ^SQLite will never request a scratch buffer that is more than 6 1643 ** times the database page size. 1644 ** ^If SQLite needs needs additional 1645 ** scratch memory beyond what is provided by this configuration option, then 1646 ** [sqlite3_malloc()] will be used to obtain the memory needed.<p> 1647 ** ^When the application provides any amount of scratch memory using 1648 ** SQLITE_CONFIG_SCRATCH, SQLite avoids unnecessary large 1649 ** [sqlite3_malloc|heap allocations]. 1650 ** This can help [Robson proof|prevent memory allocation failures] due to heap 1651 ** fragmentation in low-memory embedded systems. 1652 ** </dd> 1653 ** 1654 ** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1655 ** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool 1656 ** that SQLite can use for the database page cache with the default page 1657 ** cache implementation. 1658 ** This configuration option is a no-op if an application-define page 1659 ** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2]. 1660 ** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to 1661 ** 8-byte aligned memory (pMem), the size of each page cache line (sz), 1662 ** and the number of cache lines (N). 1663 ** The sz argument should be the size of the largest database page 1664 ** (a power of two between 512 and 65536) plus some extra bytes for each 1665 ** page header. ^The number of extra bytes needed by the page header 1666 ** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ]. 1667 ** ^It is harmless, apart from the wasted memory, 1668 ** for the sz parameter to be larger than necessary. The pMem 1669 ** argument must be either a NULL pointer or a pointer to an 8-byte 1670 ** aligned block of memory of at least sz*N bytes, otherwise 1671 ** subsequent behavior is undefined. 1672 ** ^When pMem is not NULL, SQLite will strive to use the memory provided 1673 ** to satisfy page cache needs, falling back to [sqlite3_malloc()] if 1674 ** a page cache line is larger than sz bytes or if all of the pMem buffer 1675 ** is exhausted. 1676 ** ^If pMem is NULL and N is non-zero, then each database connection 1677 ** does an initial bulk allocation for page cache memory 1678 ** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or 1679 ** of -1024*N bytes if N is negative, . ^If additional 1680 ** page cache memory is needed beyond what is provided by the initial 1681 ** allocation, then SQLite goes to [sqlite3_malloc()] separately for each 1682 ** additional cache line. </dd> 1683 ** 1684 ** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1685 ** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer 1686 ** that SQLite will use for all of its dynamic memory allocation needs 1687 ** beyond those provided for by [SQLITE_CONFIG_SCRATCH] and 1688 ** [SQLITE_CONFIG_PAGECACHE]. 1689 ** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled 1690 ** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns 1691 ** [SQLITE_ERROR] if invoked otherwise. 1692 ** ^There are three arguments to SQLITE_CONFIG_HEAP: 1693 ** An 8-byte aligned pointer to the memory, 1694 ** the number of bytes in the memory buffer, and the minimum allocation size. 1695 ** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1696 ** to using its default memory allocator (the system malloc() implementation), 1697 ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1698 ** memory pointer is not NULL then the alternative memory 1699 ** allocator is engaged to handle all of SQLites memory allocation needs. 1700 ** The first pointer (the memory pointer) must be aligned to an 8-byte 1701 ** boundary or subsequent behavior of SQLite will be undefined. 1702 ** The minimum allocation size is capped at 2**12. Reasonable values 1703 ** for the minimum allocation size are 2**5 through 2**8.</dd> 1704 ** 1705 ** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1706 ** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a 1707 ** pointer to an instance of the [sqlite3_mutex_methods] structure. 1708 ** The argument specifies alternative low-level mutex routines to be used 1709 ** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of 1710 ** the content of the [sqlite3_mutex_methods] structure before the call to 1711 ** [sqlite3_config()] returns. ^If SQLite is compiled with 1712 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1713 ** the entire mutexing subsystem is omitted from the build and hence calls to 1714 ** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1715 ** return [SQLITE_ERROR].</dd> 1716 ** 1717 ** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1718 ** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which 1719 ** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The 1720 ** [sqlite3_mutex_methods] 1721 ** structure is filled with the currently defined mutex routines.)^ 1722 ** This option can be used to overload the default mutex allocation 1723 ** routines with a wrapper used to track mutex usage for performance 1724 ** profiling or testing, for example. ^If SQLite is compiled with 1725 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1726 ** the entire mutexing subsystem is omitted from the build and hence calls to 1727 ** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1728 ** return [SQLITE_ERROR].</dd> 1729 ** 1730 ** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1731 ** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine 1732 ** the default size of lookaside memory on each [database connection]. 1733 ** The first argument is the 1734 ** size of each lookaside buffer slot and the second is the number of 1735 ** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE 1736 ** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1737 ** option to [sqlite3_db_config()] can be used to change the lookaside 1738 ** configuration on individual connections.)^ </dd> 1739 ** 1740 ** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> 1741 ** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is 1742 ** a pointer to an [sqlite3_pcache_methods2] object. This object specifies 1743 ** the interface to a custom page cache implementation.)^ 1744 ** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd> 1745 ** 1746 ** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> 1747 ** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which 1748 ** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of 1749 ** the current page cache implementation into that object.)^ </dd> 1750 ** 1751 ** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1752 ** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite 1753 ** global [error log]. 1754 ** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1755 ** function with a call signature of void(*)(void*,int,const char*), 1756 ** and a pointer to void. ^If the function pointer is not NULL, it is 1757 ** invoked by [sqlite3_log()] to process each logging event. ^If the 1758 ** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1759 ** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1760 ** passed through as the first parameter to the application-defined logger 1761 ** function whenever that function is invoked. ^The second parameter to 1762 ** the logger function is a copy of the first parameter to the corresponding 1763 ** [sqlite3_log()] call and is intended to be a [result code] or an 1764 ** [extended result code]. ^The third parameter passed to the logger is 1765 ** log message after formatting via [sqlite3_snprintf()]. 1766 ** The SQLite logging interface is not reentrant; the logger function 1767 ** supplied by the application must not invoke any SQLite interface. 1768 ** In a multi-threaded application, the application-defined logger 1769 ** function must be threadsafe. </dd> 1770 ** 1771 ** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1772 ** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int. 1773 ** If non-zero, then URI handling is globally enabled. If the parameter is zero, 1774 ** then URI handling is globally disabled.)^ ^If URI handling is globally 1775 ** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()], 1776 ** [sqlite3_open16()] or 1777 ** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1778 ** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1779 ** connection is opened. ^If it is globally disabled, filenames are 1780 ** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1781 ** database connection is opened. ^(By default, URI handling is globally 1782 ** disabled. The default value may be changed by compiling with the 1783 ** [SQLITE_USE_URI] symbol defined.)^ 1784 ** 1785 ** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN 1786 ** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer 1787 ** argument which is interpreted as a boolean in order to enable or disable 1788 ** the use of covering indices for full table scans in the query optimizer. 1789 ** ^The default setting is determined 1790 ** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on" 1791 ** if that compile-time option is omitted. 1792 ** The ability to disable the use of covering indices for full table scans 1793 ** is because some incorrectly coded legacy applications might malfunction 1794 ** when the optimization is enabled. Providing the ability to 1795 ** disable the optimization allows the older, buggy application code to work 1796 ** without change even with newer versions of SQLite. 1797 ** 1798 ** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]] 1799 ** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE 1800 ** <dd> These options are obsolete and should not be used by new code. 1801 ** They are retained for backwards compatibility but are now no-ops. 1802 ** </dd> 1803 ** 1804 ** [[SQLITE_CONFIG_SQLLOG]] 1805 ** <dt>SQLITE_CONFIG_SQLLOG 1806 ** <dd>This option is only available if sqlite is compiled with the 1807 ** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should 1808 ** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int). 1809 ** The second should be of type (void*). The callback is invoked by the library 1810 ** in three separate circumstances, identified by the value passed as the 1811 ** fourth parameter. If the fourth parameter is 0, then the database connection 1812 ** passed as the second argument has just been opened. The third argument 1813 ** points to a buffer containing the name of the main database file. If the 1814 ** fourth parameter is 1, then the SQL statement that the third parameter 1815 ** points to has just been executed. Or, if the fourth parameter is 2, then 1816 ** the connection being passed as the second parameter is being closed. The 1817 ** third parameter is passed NULL In this case. An example of using this 1818 ** configuration option can be seen in the "test_sqllog.c" source file in 1819 ** the canonical SQLite source tree.</dd> 1820 ** 1821 ** [[SQLITE_CONFIG_MMAP_SIZE]] 1822 ** <dt>SQLITE_CONFIG_MMAP_SIZE 1823 ** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values 1824 ** that are the default mmap size limit (the default setting for 1825 ** [PRAGMA mmap_size]) and the maximum allowed mmap size limit. 1826 ** ^The default setting can be overridden by each database connection using 1827 ** either the [PRAGMA mmap_size] command, or by using the 1828 ** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size 1829 ** will be silently truncated if necessary so that it does not exceed the 1830 ** compile-time maximum mmap size set by the 1831 ** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^ 1832 ** ^If either argument to this option is negative, then that argument is 1833 ** changed to its compile-time default. 1834 ** 1835 ** [[SQLITE_CONFIG_WIN32_HEAPSIZE]] 1836 ** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE 1837 ** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is 1838 ** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro 1839 ** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value 1840 ** that specifies the maximum size of the created heap. 1841 ** 1842 ** [[SQLITE_CONFIG_PCACHE_HDRSZ]] 1843 ** <dt>SQLITE_CONFIG_PCACHE_HDRSZ 1844 ** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which 1845 ** is a pointer to an integer and writes into that integer the number of extra 1846 ** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE]. 1847 ** The amount of extra space required can change depending on the compiler, 1848 ** target platform, and SQLite version. 1849 ** 1850 ** [[SQLITE_CONFIG_PMASZ]] 1851 ** <dt>SQLITE_CONFIG_PMASZ 1852 ** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which 1853 ** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded 1854 ** sorter to that integer. The default minimum PMA Size is set by the 1855 ** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched 1856 ** to help with sort operations when multithreaded sorting 1857 ** is enabled (using the [PRAGMA threads] command) and the amount of content 1858 ** to be sorted exceeds the page size times the minimum of the 1859 ** [PRAGMA cache_size] setting and this value. 1860 ** 1861 ** [[SQLITE_CONFIG_STMTJRNL_SPILL]] 1862 ** <dt>SQLITE_CONFIG_STMTJRNL_SPILL 1863 ** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which 1864 ** becomes the [statement journal] spill-to-disk threshold. 1865 ** [Statement journals] are held in memory until their size (in bytes) 1866 ** exceeds this threshold, at which point they are written to disk. 1867 ** Or if the threshold is -1, statement journals are always held 1868 ** exclusively in memory. 1869 ** Since many statement journals never become large, setting the spill 1870 ** threshold to a value such as 64KiB can greatly reduce the amount of 1871 ** I/O required to support statement rollback. 1872 ** The default value for this setting is controlled by the 1873 ** [SQLITE_STMTJRNL_SPILL] compile-time option. 1874 ** </dl> 1875 */ 1876 #define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1877 #define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1878 #define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1879 #define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1880 #define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1881 #define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1882 #define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1883 #define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1884 #define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1885 #define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1886 #define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1887 /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1888 #define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1889 #define SQLITE_CONFIG_PCACHE 14 /* no-op */ 1890 #define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 1891 #define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1892 #define SQLITE_CONFIG_URI 17 /* int */ 1893 #define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 1894 #define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 1895 #define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */ 1896 #define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */ 1897 #define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */ 1898 #define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */ 1899 #define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */ 1900 #define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */ 1901 #define SQLITE_CONFIG_STMTJRNL_SPILL 26 /* int nByte */ 1902 1903 /* 1904 ** CAPI3REF: Database Connection Configuration Options 1905 ** 1906 ** These constants are the available integer configuration options that 1907 ** can be passed as the second argument to the [sqlite3_db_config()] interface. 1908 ** 1909 ** New configuration options may be added in future releases of SQLite. 1910 ** Existing configuration options might be discontinued. Applications 1911 ** should check the return code from [sqlite3_db_config()] to make sure that 1912 ** the call worked. ^The [sqlite3_db_config()] interface will return a 1913 ** non-zero [error code] if a discontinued or unsupported configuration option 1914 ** is invoked. 1915 ** 1916 ** <dl> 1917 ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1918 ** <dd> ^This option takes three additional arguments that determine the 1919 ** [lookaside memory allocator] configuration for the [database connection]. 1920 ** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1921 ** pointer to a memory buffer to use for lookaside memory. 1922 ** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1923 ** may be NULL in which case SQLite will allocate the 1924 ** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1925 ** size of each lookaside buffer slot. ^The third argument is the number of 1926 ** slots. The size of the buffer in the first argument must be greater than 1927 ** or equal to the product of the second and third arguments. The buffer 1928 ** must be aligned to an 8-byte boundary. ^If the second argument to 1929 ** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1930 ** rounded down to the next smaller multiple of 8. ^(The lookaside memory 1931 ** configuration for a database connection can only be changed when that 1932 ** connection is not currently using lookaside memory, or in other words 1933 ** when the "current value" returned by 1934 ** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 1935 ** Any attempt to change the lookaside memory configuration when lookaside 1936 ** memory is in use leaves the configuration unchanged and returns 1937 ** [SQLITE_BUSY].)^</dd> 1938 ** 1939 ** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 1940 ** <dd> ^This option is used to enable or disable the enforcement of 1941 ** [foreign key constraints]. There should be two additional arguments. 1942 ** The first argument is an integer which is 0 to disable FK enforcement, 1943 ** positive to enable FK enforcement or negative to leave FK enforcement 1944 ** unchanged. The second parameter is a pointer to an integer into which 1945 ** is written 0 or 1 to indicate whether FK enforcement is off or on 1946 ** following this call. The second parameter may be a NULL pointer, in 1947 ** which case the FK enforcement setting is not reported back. </dd> 1948 ** 1949 ** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 1950 ** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 1951 ** There should be two additional arguments. 1952 ** The first argument is an integer which is 0 to disable triggers, 1953 ** positive to enable triggers or negative to leave the setting unchanged. 1954 ** The second parameter is a pointer to an integer into which 1955 ** is written 0 or 1 to indicate whether triggers are disabled or enabled 1956 ** following this call. The second parameter may be a NULL pointer, in 1957 ** which case the trigger setting is not reported back. </dd> 1958 ** 1959 ** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt> 1960 ** <dd> ^This option is used to enable or disable the two-argument 1961 ** version of the [fts3_tokenizer()] function which is part of the 1962 ** [FTS3] full-text search engine extension. 1963 ** There should be two additional arguments. 1964 ** The first argument is an integer which is 0 to disable fts3_tokenizer() or 1965 ** positive to enable fts3_tokenizer() or negative to leave the setting 1966 ** unchanged. 1967 ** The second parameter is a pointer to an integer into which 1968 ** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled 1969 ** following this call. The second parameter may be a NULL pointer, in 1970 ** which case the new setting is not reported back. </dd> 1971 ** 1972 ** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt> 1973 ** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()] 1974 ** interface independently of the [load_extension()] SQL function. 1975 ** The [sqlite3_enable_load_extension()] API enables or disables both the 1976 ** C-API [sqlite3_load_extension()] and the SQL function [load_extension()]. 1977 ** There should be two additional arguments. 1978 ** When the first argument to this interface is 1, then only the C-API is 1979 ** enabled and the SQL function remains disabled. If the first argument to 1980 ** this interface is 0, then both the C-API and the SQL function are disabled. 1981 ** If the first argument is -1, then no changes are made to state of either the 1982 ** C-API or the SQL function. 1983 ** The second parameter is a pointer to an integer into which 1984 ** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface 1985 ** is disabled or enabled following this call. The second parameter may 1986 ** be a NULL pointer, in which case the new setting is not reported back. 1987 ** </dd> 1988 ** 1989 ** <dt>SQLITE_DBCONFIG_MAINDBNAME</dt> 1990 ** <dd> ^This option is used to change the name of the "main" database 1991 ** schema. ^The sole argument is a pointer to a constant UTF8 string 1992 ** which will become the new schema name in place of "main". ^SQLite 1993 ** does not make a copy of the new main schema name string, so the application 1994 ** must ensure that the argument passed into this DBCONFIG option is unchanged 1995 ** until after the database connection closes. 1996 ** </dd> 1997 ** 1998 ** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt> 1999 ** <dd> Usually, when a database in wal mode is closed or detached from a 2000 ** database handle, SQLite checks if this will mean that there are now no 2001 ** connections at all to the database. If so, it performs a checkpoint 2002 ** operation before closing the connection. This option may be used to 2003 ** override this behaviour. The first parameter passed to this operation 2004 ** is an integer - non-zero to disable checkpoints-on-close, or zero (the 2005 ** default) to enable them. The second parameter is a pointer to an integer 2006 ** into which is written 0 or 1 to indicate whether checkpoints-on-close 2007 ** have been disabled - 0 if they are not disabled, 1 if they are. 2008 ** </dd> 2009 ** 2010 ** <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt> 2011 ** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates 2012 ** the [query planner stability guarantee] (QPSG). When the QPSG is active, 2013 ** a single SQL query statement will always use the same algorithm regardless 2014 ** of values of [bound parameters].)^ The QPSG disables some query optimizations 2015 ** that look at the values of bound parameters, which can make some queries 2016 ** slower. But the QPSG has the advantage of more predictable behavior. With 2017 ** the QPSG active, SQLite will always use the same query plan in the field as 2018 ** was used during testing in the lab. 2019 ** </dd> 2020 ** 2021 ** </dl> 2022 */ 2023 #define SQLITE_DBCONFIG_MAINDBNAME 1000 /* const char* */ 2024 #define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 2025 #define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 2026 #define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 2027 #define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */ 2028 #define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */ 2029 #define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE 1006 /* int int* */ 2030 #define SQLITE_DBCONFIG_ENABLE_QPSG 1007 /* int int* */ 2031 2032 2033 /* 2034 ** CAPI3REF: Enable Or Disable Extended Result Codes 2035 ** METHOD: sqlite3 2036 ** 2037 ** ^The sqlite3_extended_result_codes() routine enables or disables the 2038 ** [extended result codes] feature of SQLite. ^The extended result 2039 ** codes are disabled by default for historical compatibility. 2040 */ 2041 SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff); 2042 2043 /* 2044 ** CAPI3REF: Last Insert Rowid 2045 ** METHOD: sqlite3 2046 ** 2047 ** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables) 2048 ** has a unique 64-bit signed 2049 ** integer key called the [ROWID | "rowid"]. ^The rowid is always available 2050 ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 2051 ** names are not also used by explicitly declared columns. ^If 2052 ** the table has a column of type [INTEGER PRIMARY KEY] then that column 2053 ** is another alias for the rowid. 2054 ** 2055 ** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of 2056 ** the most recent successful [INSERT] into a rowid table or [virtual table] 2057 ** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not 2058 ** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred 2059 ** on the database connection D, then sqlite3_last_insert_rowid(D) returns 2060 ** zero. 2061 ** 2062 ** As well as being set automatically as rows are inserted into database 2063 ** tables, the value returned by this function may be set explicitly by 2064 ** [sqlite3_set_last_insert_rowid()] 2065 ** 2066 ** Some virtual table implementations may INSERT rows into rowid tables as 2067 ** part of committing a transaction (e.g. to flush data accumulated in memory 2068 ** to disk). In this case subsequent calls to this function return the rowid 2069 ** associated with these internal INSERT operations, which leads to 2070 ** unintuitive results. Virtual table implementations that do write to rowid 2071 ** tables in this way can avoid this problem by restoring the original 2072 ** rowid value using [sqlite3_set_last_insert_rowid()] before returning 2073 ** control to the user. 2074 ** 2075 ** ^(If an [INSERT] occurs within a trigger then this routine will 2076 ** return the [rowid] of the inserted row as long as the trigger is 2077 ** running. Once the trigger program ends, the value returned 2078 ** by this routine reverts to what it was before the trigger was fired.)^ 2079 ** 2080 ** ^An [INSERT] that fails due to a constraint violation is not a 2081 ** successful [INSERT] and does not change the value returned by this 2082 ** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 2083 ** and INSERT OR ABORT make no changes to the return value of this 2084 ** routine when their insertion fails. ^(When INSERT OR REPLACE 2085 ** encounters a constraint violation, it does not fail. The 2086 ** INSERT continues to completion after deleting rows that caused 2087 ** the constraint problem so INSERT OR REPLACE will always change 2088 ** the return value of this interface.)^ 2089 ** 2090 ** ^For the purposes of this routine, an [INSERT] is considered to 2091 ** be successful even if it is subsequently rolled back. 2092 ** 2093 ** This function is accessible to SQL statements via the 2094 ** [last_insert_rowid() SQL function]. 2095 ** 2096 ** If a separate thread performs a new [INSERT] on the same 2097 ** database connection while the [sqlite3_last_insert_rowid()] 2098 ** function is running and thus changes the last insert [rowid], 2099 ** then the value returned by [sqlite3_last_insert_rowid()] is 2100 ** unpredictable and might not equal either the old or the new 2101 ** last insert [rowid]. 2102 */ 2103 SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 2104 2105 /* 2106 ** CAPI3REF: Set the Last Insert Rowid value. 2107 ** METHOD: sqlite3 2108 ** 2109 ** The sqlite3_set_last_insert_rowid(D, R) method allows the application to 2110 ** set the value returned by calling sqlite3_last_insert_rowid(D) to R 2111 ** without inserting a row into the database. 2112 */ 2113 SQLITE_API void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64); 2114 2115 /* 2116 ** CAPI3REF: Count The Number Of Rows Modified 2117 ** METHOD: sqlite3 2118 ** 2119 ** ^This function returns the number of rows modified, inserted or 2120 ** deleted by the most recently completed INSERT, UPDATE or DELETE 2121 ** statement on the database connection specified by the only parameter. 2122 ** ^Executing any other type of SQL statement does not modify the value 2123 ** returned by this function. 2124 ** 2125 ** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are 2126 ** considered - auxiliary changes caused by [CREATE TRIGGER | triggers], 2127 ** [foreign key actions] or [REPLACE] constraint resolution are not counted. 2128 ** 2129 ** Changes to a view that are intercepted by 2130 ** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value 2131 ** returned by sqlite3_changes() immediately after an INSERT, UPDATE or 2132 ** DELETE statement run on a view is always zero. Only changes made to real 2133 ** tables are counted. 2134 ** 2135 ** Things are more complicated if the sqlite3_changes() function is 2136 ** executed while a trigger program is running. This may happen if the 2137 ** program uses the [changes() SQL function], or if some other callback 2138 ** function invokes sqlite3_changes() directly. Essentially: 2139 ** 2140 ** <ul> 2141 ** <li> ^(Before entering a trigger program the value returned by 2142 ** sqlite3_changes() function is saved. After the trigger program 2143 ** has finished, the original value is restored.)^ 2144 ** 2145 ** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE 2146 ** statement sets the value returned by sqlite3_changes() 2147 ** upon completion as normal. Of course, this value will not include 2148 ** any changes performed by sub-triggers, as the sqlite3_changes() 2149 ** value will be saved and restored after each sub-trigger has run.)^ 2150 ** </ul> 2151 ** 2152 ** ^This means that if the changes() SQL function (or similar) is used 2153 ** by the first INSERT, UPDATE or DELETE statement within a trigger, it 2154 ** returns the value as set when the calling statement began executing. 2155 ** ^If it is used by the second or subsequent such statement within a trigger 2156 ** program, the value returned reflects the number of rows modified by the 2157 ** previous INSERT, UPDATE or DELETE statement within the same trigger. 2158 ** 2159 ** See also the [sqlite3_total_changes()] interface, the 2160 ** [count_changes pragma], and the [changes() SQL function]. 2161 ** 2162 ** If a separate thread makes changes on the same database connection 2163 ** while [sqlite3_changes()] is running then the value returned 2164 ** is unpredictable and not meaningful. 2165 */ 2166 SQLITE_API int sqlite3_changes(sqlite3*); 2167 2168 /* 2169 ** CAPI3REF: Total Number Of Rows Modified 2170 ** METHOD: sqlite3 2171 ** 2172 ** ^This function returns the total number of rows inserted, modified or 2173 ** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed 2174 ** since the database connection was opened, including those executed as 2175 ** part of trigger programs. ^Executing any other type of SQL statement 2176 ** does not affect the value returned by sqlite3_total_changes(). 2177 ** 2178 ** ^Changes made as part of [foreign key actions] are included in the 2179 ** count, but those made as part of REPLACE constraint resolution are 2180 ** not. ^Changes to a view that are intercepted by INSTEAD OF triggers 2181 ** are not counted. 2182 ** 2183 ** See also the [sqlite3_changes()] interface, the 2184 ** [count_changes pragma], and the [total_changes() SQL function]. 2185 ** 2186 ** If a separate thread makes changes on the same database connection 2187 ** while [sqlite3_total_changes()] is running then the value 2188 ** returned is unpredictable and not meaningful. 2189 */ 2190 SQLITE_API int sqlite3_total_changes(sqlite3*); 2191 2192 /* 2193 ** CAPI3REF: Interrupt A Long-Running Query 2194 ** METHOD: sqlite3 2195 ** 2196 ** ^This function causes any pending database operation to abort and 2197 ** return at its earliest opportunity. This routine is typically 2198 ** called in response to a user action such as pressing "Cancel" 2199 ** or Ctrl-C where the user wants a long query operation to halt 2200 ** immediately. 2201 ** 2202 ** ^It is safe to call this routine from a thread different from the 2203 ** thread that is currently running the database operation. But it 2204 ** is not safe to call this routine with a [database connection] that 2205 ** is closed or might close before sqlite3_interrupt() returns. 2206 ** 2207 ** ^If an SQL operation is very nearly finished at the time when 2208 ** sqlite3_interrupt() is called, then it might not have an opportunity 2209 ** to be interrupted and might continue to completion. 2210 ** 2211 ** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 2212 ** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 2213 ** that is inside an explicit transaction, then the entire transaction 2214 ** will be rolled back automatically. 2215 ** 2216 ** ^The sqlite3_interrupt(D) call is in effect until all currently running 2217 ** SQL statements on [database connection] D complete. ^Any new SQL statements 2218 ** that are started after the sqlite3_interrupt() call and before the 2219 ** running statements reaches zero are interrupted as if they had been 2220 ** running prior to the sqlite3_interrupt() call. ^New SQL statements 2221 ** that are started after the running statement count reaches zero are 2222 ** not effected by the sqlite3_interrupt(). 2223 ** ^A call to sqlite3_interrupt(D) that occurs when there are no running 2224 ** SQL statements is a no-op and has no effect on SQL statements 2225 ** that are started after the sqlite3_interrupt() call returns. 2226 */ 2227 SQLITE_API void sqlite3_interrupt(sqlite3*); 2228 2229 /* 2230 ** CAPI3REF: Determine If An SQL Statement Is Complete 2231 ** 2232 ** These routines are useful during command-line input to determine if the 2233 ** currently entered text seems to form a complete SQL statement or 2234 ** if additional input is needed before sending the text into 2235 ** SQLite for parsing. ^These routines return 1 if the input string 2236 ** appears to be a complete SQL statement. ^A statement is judged to be 2237 ** complete if it ends with a semicolon token and is not a prefix of a 2238 ** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 2239 ** string literals or quoted identifier names or comments are not 2240 ** independent tokens (they are part of the token in which they are 2241 ** embedded) and thus do not count as a statement terminator. ^Whitespace 2242 ** and comments that follow the final semicolon are ignored. 2243 ** 2244 ** ^These routines return 0 if the statement is incomplete. ^If a 2245 ** memory allocation fails, then SQLITE_NOMEM is returned. 2246 ** 2247 ** ^These routines do not parse the SQL statements thus 2248 ** will not detect syntactically incorrect SQL. 2249 ** 2250 ** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 2251 ** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 2252 ** automatically by sqlite3_complete16(). If that initialization fails, 2253 ** then the return value from sqlite3_complete16() will be non-zero 2254 ** regardless of whether or not the input SQL is complete.)^ 2255 ** 2256 ** The input to [sqlite3_complete()] must be a zero-terminated 2257 ** UTF-8 string. 2258 ** 2259 ** The input to [sqlite3_complete16()] must be a zero-terminated 2260 ** UTF-16 string in native byte order. 2261 */ 2262 SQLITE_API int sqlite3_complete(const char *sql); 2263 SQLITE_API int sqlite3_complete16(const void *sql); 2264 2265 /* 2266 ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 2267 ** KEYWORDS: {busy-handler callback} {busy handler} 2268 ** METHOD: sqlite3 2269 ** 2270 ** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X 2271 ** that might be invoked with argument P whenever 2272 ** an attempt is made to access a database table associated with 2273 ** [database connection] D when another thread 2274 ** or process has the table locked. 2275 ** The sqlite3_busy_handler() interface is used to implement 2276 ** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout]. 2277 ** 2278 ** ^If the busy callback is NULL, then [SQLITE_BUSY] 2279 ** is returned immediately upon encountering the lock. ^If the busy callback 2280 ** is not NULL, then the callback might be invoked with two arguments. 2281 ** 2282 ** ^The first argument to the busy handler is a copy of the void* pointer which 2283 ** is the third argument to sqlite3_busy_handler(). ^The second argument to 2284 ** the busy handler callback is the number of times that the busy handler has 2285 ** been invoked previously for the same locking event. ^If the 2286 ** busy callback returns 0, then no additional attempts are made to 2287 ** access the database and [SQLITE_BUSY] is returned 2288 ** to the application. 2289 ** ^If the callback returns non-zero, then another attempt 2290 ** is made to access the database and the cycle repeats. 2291 ** 2292 ** The presence of a busy handler does not guarantee that it will be invoked 2293 ** when there is lock contention. ^If SQLite determines that invoking the busy 2294 ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 2295 ** to the application instead of invoking the 2296 ** busy handler. 2297 ** Consider a scenario where one process is holding a read lock that 2298 ** it is trying to promote to a reserved lock and 2299 ** a second process is holding a reserved lock that it is trying 2300 ** to promote to an exclusive lock. The first process cannot proceed 2301 ** because it is blocked by the second and the second process cannot 2302 ** proceed because it is blocked by the first. If both processes 2303 ** invoke the busy handlers, neither will make any progress. Therefore, 2304 ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 2305 ** will induce the first process to release its read lock and allow 2306 ** the second process to proceed. 2307 ** 2308 ** ^The default busy callback is NULL. 2309 ** 2310 ** ^(There can only be a single busy handler defined for each 2311 ** [database connection]. Setting a new busy handler clears any 2312 ** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 2313 ** or evaluating [PRAGMA busy_timeout=N] will change the 2314 ** busy handler and thus clear any previously set busy handler. 2315 ** 2316 ** The busy callback should not take any actions which modify the 2317 ** database connection that invoked the busy handler. In other words, 2318 ** the busy handler is not reentrant. Any such actions 2319 ** result in undefined behavior. 2320 ** 2321 ** A busy handler must not close the database connection 2322 ** or [prepared statement] that invoked the busy handler. 2323 */ 2324 SQLITE_API int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*); 2325 2326 /* 2327 ** CAPI3REF: Set A Busy Timeout 2328 ** METHOD: sqlite3 2329 ** 2330 ** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 2331 ** for a specified amount of time when a table is locked. ^The handler 2332 ** will sleep multiple times until at least "ms" milliseconds of sleeping 2333 ** have accumulated. ^After at least "ms" milliseconds of sleeping, 2334 ** the handler returns 0 which causes [sqlite3_step()] to return 2335 ** [SQLITE_BUSY]. 2336 ** 2337 ** ^Calling this routine with an argument less than or equal to zero 2338 ** turns off all busy handlers. 2339 ** 2340 ** ^(There can only be a single busy handler for a particular 2341 ** [database connection] at any given moment. If another busy handler 2342 ** was defined (using [sqlite3_busy_handler()]) prior to calling 2343 ** this routine, that other busy handler is cleared.)^ 2344 ** 2345 ** See also: [PRAGMA busy_timeout] 2346 */ 2347 SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms); 2348 2349 /* 2350 ** CAPI3REF: Convenience Routines For Running Queries 2351 ** METHOD: sqlite3 2352 ** 2353 ** This is a legacy interface that is preserved for backwards compatibility. 2354 ** Use of this interface is not recommended. 2355 ** 2356 ** Definition: A <b>result table</b> is memory data structure created by the 2357 ** [sqlite3_get_table()] interface. A result table records the 2358 ** complete query results from one or more queries. 2359 ** 2360 ** The table conceptually has a number of rows and columns. But 2361 ** these numbers are not part of the result table itself. These 2362 ** numbers are obtained separately. Let N be the number of rows 2363 ** and M be the number of columns. 2364 ** 2365 ** A result table is an array of pointers to zero-terminated UTF-8 strings. 2366 ** There are (N+1)*M elements in the array. The first M pointers point 2367 ** to zero-terminated strings that contain the names of the columns. 2368 ** The remaining entries all point to query results. NULL values result 2369 ** in NULL pointers. All other values are in their UTF-8 zero-terminated 2370 ** string representation as returned by [sqlite3_column_text()]. 2371 ** 2372 ** A result table might consist of one or more memory allocations. 2373 ** It is not safe to pass a result table directly to [sqlite3_free()]. 2374 ** A result table should be deallocated using [sqlite3_free_table()]. 2375 ** 2376 ** ^(As an example of the result table format, suppose a query result 2377 ** is as follows: 2378 ** 2379 ** <blockquote><pre> 2380 ** Name | Age 2381 ** ----------------------- 2382 ** Alice | 43 2383 ** Bob | 28 2384 ** Cindy | 21 2385 ** </pre></blockquote> 2386 ** 2387 ** There are two column (M==2) and three rows (N==3). Thus the 2388 ** result table has 8 entries. Suppose the result table is stored 2389 ** in an array names azResult. Then azResult holds this content: 2390 ** 2391 ** <blockquote><pre> 2392 ** azResult[0] = "Name"; 2393 ** azResult[1] = "Age"; 2394 ** azResult[2] = "Alice"; 2395 ** azResult[3] = "43"; 2396 ** azResult[4] = "Bob"; 2397 ** azResult[5] = "28"; 2398 ** azResult[6] = "Cindy"; 2399 ** azResult[7] = "21"; 2400 ** </pre></blockquote>)^ 2401 ** 2402 ** ^The sqlite3_get_table() function evaluates one or more 2403 ** semicolon-separated SQL statements in the zero-terminated UTF-8 2404 ** string of its 2nd parameter and returns a result table to the 2405 ** pointer given in its 3rd parameter. 2406 ** 2407 ** After the application has finished with the result from sqlite3_get_table(), 2408 ** it must pass the result table pointer to sqlite3_free_table() in order to 2409 ** release the memory that was malloced. Because of the way the 2410 ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 2411 ** function must not try to call [sqlite3_free()] directly. Only 2412 ** [sqlite3_free_table()] is able to release the memory properly and safely. 2413 ** 2414 ** The sqlite3_get_table() interface is implemented as a wrapper around 2415 ** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2416 ** to any internal data structures of SQLite. It uses only the public 2417 ** interface defined here. As a consequence, errors that occur in the 2418 ** wrapper layer outside of the internal [sqlite3_exec()] call are not 2419 ** reflected in subsequent calls to [sqlite3_errcode()] or 2420 ** [sqlite3_errmsg()]. 2421 */ 2422 SQLITE_API int sqlite3_get_table( 2423 sqlite3 *db, /* An open database */ 2424 const char *zSql, /* SQL to be evaluated */ 2425 char ***pazResult, /* Results of the query */ 2426 int *pnRow, /* Number of result rows written here */ 2427 int *pnColumn, /* Number of result columns written here */ 2428 char **pzErrmsg /* Error msg written here */ 2429 ); 2430 SQLITE_API void sqlite3_free_table(char **result); 2431 2432 /* 2433 ** CAPI3REF: Formatted String Printing Functions 2434 ** 2435 ** These routines are work-alikes of the "printf()" family of functions 2436 ** from the standard C library. 2437 ** These routines understand most of the common K&R formatting options, 2438 ** plus some additional non-standard formats, detailed below. 2439 ** Note that some of the more obscure formatting options from recent 2440 ** C-library standards are omitted from this implementation. 2441 ** 2442 ** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2443 ** results into memory obtained from [sqlite3_malloc()]. 2444 ** The strings returned by these two routines should be 2445 ** released by [sqlite3_free()]. ^Both routines return a 2446 ** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 2447 ** memory to hold the resulting string. 2448 ** 2449 ** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2450 ** the standard C library. The result is written into the 2451 ** buffer supplied as the second parameter whose size is given by 2452 ** the first parameter. Note that the order of the 2453 ** first two parameters is reversed from snprintf().)^ This is an 2454 ** historical accident that cannot be fixed without breaking 2455 ** backwards compatibility. ^(Note also that sqlite3_snprintf() 2456 ** returns a pointer to its buffer instead of the number of 2457 ** characters actually written into the buffer.)^ We admit that 2458 ** the number of characters written would be a more useful return 2459 ** value but we cannot change the implementation of sqlite3_snprintf() 2460 ** now without breaking compatibility. 2461 ** 2462 ** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2463 ** guarantees that the buffer is always zero-terminated. ^The first 2464 ** parameter "n" is the total size of the buffer, including space for 2465 ** the zero terminator. So the longest string that can be completely 2466 ** written will be n-1 characters. 2467 ** 2468 ** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2469 ** 2470 ** These routines all implement some additional formatting 2471 ** options that are useful for constructing SQL statements. 2472 ** All of the usual printf() formatting options apply. In addition, there 2473 ** is are "%q", "%Q", "%w" and "%z" options. 2474 ** 2475 ** ^(The %q option works like %s in that it substitutes a nul-terminated 2476 ** string from the argument list. But %q also doubles every '\'' character. 2477 ** %q is designed for use inside a string literal.)^ By doubling each '\'' 2478 ** character it escapes that character and allows it to be inserted into 2479 ** the string. 2480 ** 2481 ** For example, assume the string variable zText contains text as follows: 2482 ** 2483 ** <blockquote><pre> 2484 ** char *zText = "It's a happy day!"; 2485 ** </pre></blockquote> 2486 ** 2487 ** One can use this text in an SQL statement as follows: 2488 ** 2489 ** <blockquote><pre> 2490 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 2491 ** sqlite3_exec(db, zSQL, 0, 0, 0); 2492 ** sqlite3_free(zSQL); 2493 ** </pre></blockquote> 2494 ** 2495 ** Because the %q format string is used, the '\'' character in zText 2496 ** is escaped and the SQL generated is as follows: 2497 ** 2498 ** <blockquote><pre> 2499 ** INSERT INTO table1 VALUES('It''s a happy day!') 2500 ** </pre></blockquote> 2501 ** 2502 ** This is correct. Had we used %s instead of %q, the generated SQL 2503 ** would have looked like this: 2504 ** 2505 ** <blockquote><pre> 2506 ** INSERT INTO table1 VALUES('It's a happy day!'); 2507 ** </pre></blockquote> 2508 ** 2509 ** This second example is an SQL syntax error. As a general rule you should 2510 ** always use %q instead of %s when inserting text into a string literal. 2511 ** 2512 ** ^(The %Q option works like %q except it also adds single quotes around 2513 ** the outside of the total string. Additionally, if the parameter in the 2514 ** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 2515 ** single quotes).)^ So, for example, one could say: 2516 ** 2517 ** <blockquote><pre> 2518 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 2519 ** sqlite3_exec(db, zSQL, 0, 0, 0); 2520 ** sqlite3_free(zSQL); 2521 ** </pre></blockquote> 2522 ** 2523 ** The code above will render a correct SQL statement in the zSQL 2524 ** variable even if the zText variable is a NULL pointer. 2525 ** 2526 ** ^(The "%w" formatting option is like "%q" except that it expects to 2527 ** be contained within double-quotes instead of single quotes, and it 2528 ** escapes the double-quote character instead of the single-quote 2529 ** character.)^ The "%w" formatting option is intended for safely inserting 2530 ** table and column names into a constructed SQL statement. 2531 ** 2532 ** ^(The "%z" formatting option works like "%s" but with the 2533 ** addition that after the string has been read and copied into 2534 ** the result, [sqlite3_free()] is called on the input string.)^ 2535 */ 2536 SQLITE_API char *sqlite3_mprintf(const char*,...); 2537 SQLITE_API char *sqlite3_vmprintf(const char*, va_list); 2538 SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...); 2539 SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2540 2541 /* 2542 ** CAPI3REF: Memory Allocation Subsystem 2543 ** 2544 ** The SQLite core uses these three routines for all of its own 2545 ** internal memory allocation needs. "Core" in the previous sentence 2546 ** does not include operating-system specific VFS implementation. The 2547 ** Windows VFS uses native malloc() and free() for some operations. 2548 ** 2549 ** ^The sqlite3_malloc() routine returns a pointer to a block 2550 ** of memory at least N bytes in length, where N is the parameter. 2551 ** ^If sqlite3_malloc() is unable to obtain sufficient free 2552 ** memory, it returns a NULL pointer. ^If the parameter N to 2553 ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2554 ** a NULL pointer. 2555 ** 2556 ** ^The sqlite3_malloc64(N) routine works just like 2557 ** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead 2558 ** of a signed 32-bit integer. 2559 ** 2560 ** ^Calling sqlite3_free() with a pointer previously returned 2561 ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2562 ** that it might be reused. ^The sqlite3_free() routine is 2563 ** a no-op if is called with a NULL pointer. Passing a NULL pointer 2564 ** to sqlite3_free() is harmless. After being freed, memory 2565 ** should neither be read nor written. Even reading previously freed 2566 ** memory might result in a segmentation fault or other severe error. 2567 ** Memory corruption, a segmentation fault, or other severe error 2568 ** might result if sqlite3_free() is called with a non-NULL pointer that 2569 ** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2570 ** 2571 ** ^The sqlite3_realloc(X,N) interface attempts to resize a 2572 ** prior memory allocation X to be at least N bytes. 2573 ** ^If the X parameter to sqlite3_realloc(X,N) 2574 ** is a NULL pointer then its behavior is identical to calling 2575 ** sqlite3_malloc(N). 2576 ** ^If the N parameter to sqlite3_realloc(X,N) is zero or 2577 ** negative then the behavior is exactly the same as calling 2578 ** sqlite3_free(X). 2579 ** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation 2580 ** of at least N bytes in size or NULL if insufficient memory is available. 2581 ** ^If M is the size of the prior allocation, then min(N,M) bytes 2582 ** of the prior allocation are copied into the beginning of buffer returned 2583 ** by sqlite3_realloc(X,N) and the prior allocation is freed. 2584 ** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the 2585 ** prior allocation is not freed. 2586 ** 2587 ** ^The sqlite3_realloc64(X,N) interfaces works the same as 2588 ** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead 2589 ** of a 32-bit signed integer. 2590 ** 2591 ** ^If X is a memory allocation previously obtained from sqlite3_malloc(), 2592 ** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then 2593 ** sqlite3_msize(X) returns the size of that memory allocation in bytes. 2594 ** ^The value returned by sqlite3_msize(X) might be larger than the number 2595 ** of bytes requested when X was allocated. ^If X is a NULL pointer then 2596 ** sqlite3_msize(X) returns zero. If X points to something that is not 2597 ** the beginning of memory allocation, or if it points to a formerly 2598 ** valid memory allocation that has now been freed, then the behavior 2599 ** of sqlite3_msize(X) is undefined and possibly harmful. 2600 ** 2601 ** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(), 2602 ** sqlite3_malloc64(), and sqlite3_realloc64() 2603 ** is always aligned to at least an 8 byte boundary, or to a 2604 ** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2605 ** option is used. 2606 ** 2607 ** In SQLite version 3.5.0 and 3.5.1, it was possible to define 2608 ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 2609 ** implementation of these routines to be omitted. That capability 2610 ** is no longer provided. Only built-in memory allocators can be used. 2611 ** 2612 ** Prior to SQLite version 3.7.10, the Windows OS interface layer called 2613 ** the system malloc() and free() directly when converting 2614 ** filenames between the UTF-8 encoding used by SQLite 2615 ** and whatever filename encoding is used by the particular Windows 2616 ** installation. Memory allocation errors were detected, but 2617 ** they were reported back as [SQLITE_CANTOPEN] or 2618 ** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 2619 ** 2620 ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2621 ** must be either NULL or else pointers obtained from a prior 2622 ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2623 ** not yet been released. 2624 ** 2625 ** The application must not read or write any part of 2626 ** a block of memory after it has been released using 2627 ** [sqlite3_free()] or [sqlite3_realloc()]. 2628 */ 2629 SQLITE_API void *sqlite3_malloc(int); 2630 SQLITE_API void *sqlite3_malloc64(sqlite3_uint64); 2631 SQLITE_API void *sqlite3_realloc(void*, int); 2632 SQLITE_API void *sqlite3_realloc64(void*, sqlite3_uint64); 2633 SQLITE_API void sqlite3_free(void*); 2634 SQLITE_API sqlite3_uint64 sqlite3_msize(void*); 2635 2636 /* 2637 ** CAPI3REF: Memory Allocator Statistics 2638 ** 2639 ** SQLite provides these two interfaces for reporting on the status 2640 ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2641 ** routines, which form the built-in memory allocation subsystem. 2642 ** 2643 ** ^The [sqlite3_memory_used()] routine returns the number of bytes 2644 ** of memory currently outstanding (malloced but not freed). 2645 ** ^The [sqlite3_memory_highwater()] routine returns the maximum 2646 ** value of [sqlite3_memory_used()] since the high-water mark 2647 ** was last reset. ^The values returned by [sqlite3_memory_used()] and 2648 ** [sqlite3_memory_highwater()] include any overhead 2649 ** added by SQLite in its implementation of [sqlite3_malloc()], 2650 ** but not overhead added by the any underlying system library 2651 ** routines that [sqlite3_malloc()] may call. 2652 ** 2653 ** ^The memory high-water mark is reset to the current value of 2654 ** [sqlite3_memory_used()] if and only if the parameter to 2655 ** [sqlite3_memory_highwater()] is true. ^The value returned 2656 ** by [sqlite3_memory_highwater(1)] is the high-water mark 2657 ** prior to the reset. 2658 */ 2659 SQLITE_API sqlite3_int64 sqlite3_memory_used(void); 2660 SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2661 2662 /* 2663 ** CAPI3REF: Pseudo-Random Number Generator 2664 ** 2665 ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2666 ** select random [ROWID | ROWIDs] when inserting new records into a table that 2667 ** already uses the largest possible [ROWID]. The PRNG is also used for 2668 ** the build-in random() and randomblob() SQL functions. This interface allows 2669 ** applications to access the same PRNG for other purposes. 2670 ** 2671 ** ^A call to this routine stores N bytes of randomness into buffer P. 2672 ** ^The P parameter can be a NULL pointer. 2673 ** 2674 ** ^If this routine has not been previously called or if the previous 2675 ** call had N less than one or a NULL pointer for P, then the PRNG is 2676 ** seeded using randomness obtained from the xRandomness method of 2677 ** the default [sqlite3_vfs] object. 2678 ** ^If the previous call to this routine had an N of 1 or more and a 2679 ** non-NULL P then the pseudo-randomness is generated 2680 ** internally and without recourse to the [sqlite3_vfs] xRandomness 2681 ** method. 2682 */ 2683 SQLITE_API void sqlite3_randomness(int N, void *P); 2684 2685 /* 2686 ** CAPI3REF: Compile-Time Authorization Callbacks 2687 ** METHOD: sqlite3 2688 ** KEYWORDS: {authorizer callback} 2689 ** 2690 ** ^This routine registers an authorizer callback with a particular 2691 ** [database connection], supplied in the first argument. 2692 ** ^The authorizer callback is invoked as SQL statements are being compiled 2693 ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2694 ** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()], 2695 ** and [sqlite3_prepare16_v3()]. ^At various 2696 ** points during the compilation process, as logic is being created 2697 ** to perform various actions, the authorizer callback is invoked to 2698 ** see if those actions are allowed. ^The authorizer callback should 2699 ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2700 ** specific action but allow the SQL statement to continue to be 2701 ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2702 ** rejected with an error. ^If the authorizer callback returns 2703 ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2704 ** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2705 ** the authorizer will fail with an error message. 2706 ** 2707 ** When the callback returns [SQLITE_OK], that means the operation 2708 ** requested is ok. ^When the callback returns [SQLITE_DENY], the 2709 ** [sqlite3_prepare_v2()] or equivalent call that triggered the 2710 ** authorizer will fail with an error message explaining that 2711 ** access is denied. 2712 ** 2713 ** ^The first parameter to the authorizer callback is a copy of the third 2714 ** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2715 ** to the callback is an integer [SQLITE_COPY | action code] that specifies 2716 ** the particular action to be authorized. ^The third through sixth parameters 2717 ** to the callback are either NULL pointers or zero-terminated strings 2718 ** that contain additional details about the action to be authorized. 2719 ** Applications must always be prepared to encounter a NULL pointer in any 2720 ** of the third through the sixth parameters of the authorization callback. 2721 ** 2722 ** ^If the action code is [SQLITE_READ] 2723 ** and the callback returns [SQLITE_IGNORE] then the 2724 ** [prepared statement] statement is constructed to substitute 2725 ** a NULL value in place of the table column that would have 2726 ** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2727 ** return can be used to deny an untrusted user access to individual 2728 ** columns of a table. 2729 ** ^When a table is referenced by a [SELECT] but no column values are 2730 ** extracted from that table (for example in a query like 2731 ** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback 2732 ** is invoked once for that table with a column name that is an empty string. 2733 ** ^If the action code is [SQLITE_DELETE] and the callback returns 2734 ** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2735 ** [truncate optimization] is disabled and all rows are deleted individually. 2736 ** 2737 ** An authorizer is used when [sqlite3_prepare | preparing] 2738 ** SQL statements from an untrusted source, to ensure that the SQL statements 2739 ** do not try to access data they are not allowed to see, or that they do not 2740 ** try to execute malicious statements that damage the database. For 2741 ** example, an application may allow a user to enter arbitrary 2742 ** SQL queries for evaluation by a database. But the application does 2743 ** not want the user to be able to make arbitrary changes to the 2744 ** database. An authorizer could then be put in place while the 2745 ** user-entered SQL is being [sqlite3_prepare | prepared] that 2746 ** disallows everything except [SELECT] statements. 2747 ** 2748 ** Applications that need to process SQL from untrusted sources 2749 ** might also consider lowering resource limits using [sqlite3_limit()] 2750 ** and limiting database size using the [max_page_count] [PRAGMA] 2751 ** in addition to using an authorizer. 2752 ** 2753 ** ^(Only a single authorizer can be in place on a database connection 2754 ** at a time. Each call to sqlite3_set_authorizer overrides the 2755 ** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2756 ** The authorizer is disabled by default. 2757 ** 2758 ** The authorizer callback must not do anything that will modify 2759 ** the database connection that invoked the authorizer callback. 2760 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2761 ** database connections for the meaning of "modify" in this paragraph. 2762 ** 2763 ** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2764 ** statement might be re-prepared during [sqlite3_step()] due to a 2765 ** schema change. Hence, the application should ensure that the 2766 ** correct authorizer callback remains in place during the [sqlite3_step()]. 2767 ** 2768 ** ^Note that the authorizer callback is invoked only during 2769 ** [sqlite3_prepare()] or its variants. Authorization is not 2770 ** performed during statement evaluation in [sqlite3_step()], unless 2771 ** as stated in the previous paragraph, sqlite3_step() invokes 2772 ** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2773 */ 2774 SQLITE_API int sqlite3_set_authorizer( 2775 sqlite3*, 2776 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2777 void *pUserData 2778 ); 2779 2780 /* 2781 ** CAPI3REF: Authorizer Return Codes 2782 ** 2783 ** The [sqlite3_set_authorizer | authorizer callback function] must 2784 ** return either [SQLITE_OK] or one of these two constants in order 2785 ** to signal SQLite whether or not the action is permitted. See the 2786 ** [sqlite3_set_authorizer | authorizer documentation] for additional 2787 ** information. 2788 ** 2789 ** Note that SQLITE_IGNORE is also used as a [conflict resolution mode] 2790 ** returned from the [sqlite3_vtab_on_conflict()] interface. 2791 */ 2792 #define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2793 #define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2794 2795 /* 2796 ** CAPI3REF: Authorizer Action Codes 2797 ** 2798 ** The [sqlite3_set_authorizer()] interface registers a callback function 2799 ** that is invoked to authorize certain SQL statement actions. The 2800 ** second parameter to the callback is an integer code that specifies 2801 ** what action is being authorized. These are the integer action codes that 2802 ** the authorizer callback may be passed. 2803 ** 2804 ** These action code values signify what kind of operation is to be 2805 ** authorized. The 3rd and 4th parameters to the authorization 2806 ** callback function will be parameters or NULL depending on which of these 2807 ** codes is used as the second parameter. ^(The 5th parameter to the 2808 ** authorizer callback is the name of the database ("main", "temp", 2809 ** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2810 ** is the name of the inner-most trigger or view that is responsible for 2811 ** the access attempt or NULL if this access attempt is directly from 2812 ** top-level SQL code. 2813 */ 2814 /******************************************* 3rd ************ 4th ***********/ 2815 #define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2816 #define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2817 #define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2818 #define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2819 #define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2820 #define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2821 #define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2822 #define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2823 #define SQLITE_DELETE 9 /* Table Name NULL */ 2824 #define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2825 #define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2826 #define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2827 #define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2828 #define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2829 #define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2830 #define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2831 #define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2832 #define SQLITE_INSERT 18 /* Table Name NULL */ 2833 #define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2834 #define SQLITE_READ 20 /* Table Name Column Name */ 2835 #define SQLITE_SELECT 21 /* NULL NULL */ 2836 #define SQLITE_TRANSACTION 22 /* Operation NULL */ 2837 #define SQLITE_UPDATE 23 /* Table Name Column Name */ 2838 #define SQLITE_ATTACH 24 /* Filename NULL */ 2839 #define SQLITE_DETACH 25 /* Database Name NULL */ 2840 #define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2841 #define SQLITE_REINDEX 27 /* Index Name NULL */ 2842 #define SQLITE_ANALYZE 28 /* Table Name NULL */ 2843 #define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2844 #define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2845 #define SQLITE_FUNCTION 31 /* NULL Function Name */ 2846 #define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2847 #define SQLITE_COPY 0 /* No longer used */ 2848 #define SQLITE_RECURSIVE 33 /* NULL NULL */ 2849 2850 /* 2851 ** CAPI3REF: Tracing And Profiling Functions 2852 ** METHOD: sqlite3 2853 ** 2854 ** These routines are deprecated. Use the [sqlite3_trace_v2()] interface 2855 ** instead of the routines described here. 2856 ** 2857 ** These routines register callback functions that can be used for 2858 ** tracing and profiling the execution of SQL statements. 2859 ** 2860 ** ^The callback function registered by sqlite3_trace() is invoked at 2861 ** various times when an SQL statement is being run by [sqlite3_step()]. 2862 ** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2863 ** SQL statement text as the statement first begins executing. 2864 ** ^(Additional sqlite3_trace() callbacks might occur 2865 ** as each triggered subprogram is entered. The callbacks for triggers 2866 ** contain a UTF-8 SQL comment that identifies the trigger.)^ 2867 ** 2868 ** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit 2869 ** the length of [bound parameter] expansion in the output of sqlite3_trace(). 2870 ** 2871 ** ^The callback function registered by sqlite3_profile() is invoked 2872 ** as each SQL statement finishes. ^The profile callback contains 2873 ** the original statement text and an estimate of wall-clock time 2874 ** of how long that statement took to run. ^The profile callback 2875 ** time is in units of nanoseconds, however the current implementation 2876 ** is only capable of millisecond resolution so the six least significant 2877 ** digits in the time are meaningless. Future versions of SQLite 2878 ** might provide greater resolution on the profiler callback. The 2879 ** sqlite3_profile() function is considered experimental and is 2880 ** subject to change in future versions of SQLite. 2881 */ 2882 SQLITE_API SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*, 2883 void(*xTrace)(void*,const char*), void*); 2884 SQLITE_API SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*, 2885 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2886 2887 /* 2888 ** CAPI3REF: SQL Trace Event Codes 2889 ** KEYWORDS: SQLITE_TRACE 2890 ** 2891 ** These constants identify classes of events that can be monitored 2892 ** using the [sqlite3_trace_v2()] tracing logic. The third argument 2893 ** to [sqlite3_trace_v2()] is an OR-ed combination of one or more of 2894 ** the following constants. ^The first argument to the trace callback 2895 ** is one of the following constants. 2896 ** 2897 ** New tracing constants may be added in future releases. 2898 ** 2899 ** ^A trace callback has four arguments: xCallback(T,C,P,X). 2900 ** ^The T argument is one of the integer type codes above. 2901 ** ^The C argument is a copy of the context pointer passed in as the 2902 ** fourth argument to [sqlite3_trace_v2()]. 2903 ** The P and X arguments are pointers whose meanings depend on T. 2904 ** 2905 ** <dl> 2906 ** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt> 2907 ** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement 2908 ** first begins running and possibly at other times during the 2909 ** execution of the prepared statement, such as at the start of each 2910 ** trigger subprogram. ^The P argument is a pointer to the 2911 ** [prepared statement]. ^The X argument is a pointer to a string which 2912 ** is the unexpanded SQL text of the prepared statement or an SQL comment 2913 ** that indicates the invocation of a trigger. ^The callback can compute 2914 ** the same text that would have been returned by the legacy [sqlite3_trace()] 2915 ** interface by using the X argument when X begins with "--" and invoking 2916 ** [sqlite3_expanded_sql(P)] otherwise. 2917 ** 2918 ** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt> 2919 ** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same 2920 ** information as is provided by the [sqlite3_profile()] callback. 2921 ** ^The P argument is a pointer to the [prepared statement] and the 2922 ** X argument points to a 64-bit integer which is the estimated of 2923 ** the number of nanosecond that the prepared statement took to run. 2924 ** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes. 2925 ** 2926 ** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt> 2927 ** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared 2928 ** statement generates a single row of result. 2929 ** ^The P argument is a pointer to the [prepared statement] and the 2930 ** X argument is unused. 2931 ** 2932 ** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt> 2933 ** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database 2934 ** connection closes. 2935 ** ^The P argument is a pointer to the [database connection] object 2936 ** and the X argument is unused. 2937 ** </dl> 2938 */ 2939 #define SQLITE_TRACE_STMT 0x01 2940 #define SQLITE_TRACE_PROFILE 0x02 2941 #define SQLITE_TRACE_ROW 0x04 2942 #define SQLITE_TRACE_CLOSE 0x08 2943 2944 /* 2945 ** CAPI3REF: SQL Trace Hook 2946 ** METHOD: sqlite3 2947 ** 2948 ** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback 2949 ** function X against [database connection] D, using property mask M 2950 ** and context pointer P. ^If the X callback is 2951 ** NULL or if the M mask is zero, then tracing is disabled. The 2952 ** M argument should be the bitwise OR-ed combination of 2953 ** zero or more [SQLITE_TRACE] constants. 2954 ** 2955 ** ^Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides 2956 ** (cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2(). 2957 ** 2958 ** ^The X callback is invoked whenever any of the events identified by 2959 ** mask M occur. ^The integer return value from the callback is currently 2960 ** ignored, though this may change in future releases. Callback 2961 ** implementations should return zero to ensure future compatibility. 2962 ** 2963 ** ^A trace callback is invoked with four arguments: callback(T,C,P,X). 2964 ** ^The T argument is one of the [SQLITE_TRACE] 2965 ** constants to indicate why the callback was invoked. 2966 ** ^The C argument is a copy of the context pointer. 2967 ** The P and X arguments are pointers whose meanings depend on T. 2968 ** 2969 ** The sqlite3_trace_v2() interface is intended to replace the legacy 2970 ** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which 2971 ** are deprecated. 2972 */ 2973 SQLITE_API int sqlite3_trace_v2( 2974 sqlite3*, 2975 unsigned uMask, 2976 int(*xCallback)(unsigned,void*,void*,void*), 2977 void *pCtx 2978 ); 2979 2980 /* 2981 ** CAPI3REF: Query Progress Callbacks 2982 ** METHOD: sqlite3 2983 ** 2984 ** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 2985 ** function X to be invoked periodically during long running calls to 2986 ** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 2987 ** database connection D. An example use for this 2988 ** interface is to keep a GUI updated during a large query. 2989 ** 2990 ** ^The parameter P is passed through as the only parameter to the 2991 ** callback function X. ^The parameter N is the approximate number of 2992 ** [virtual machine instructions] that are evaluated between successive 2993 ** invocations of the callback X. ^If N is less than one then the progress 2994 ** handler is disabled. 2995 ** 2996 ** ^Only a single progress handler may be defined at one time per 2997 ** [database connection]; setting a new progress handler cancels the 2998 ** old one. ^Setting parameter X to NULL disables the progress handler. 2999 ** ^The progress handler is also disabled by setting N to a value less 3000 ** than 1. 3001 ** 3002 ** ^If the progress callback returns non-zero, the operation is 3003 ** interrupted. This feature can be used to implement a 3004 ** "Cancel" button on a GUI progress dialog box. 3005 ** 3006 ** The progress handler callback must not do anything that will modify 3007 ** the database connection that invoked the progress handler. 3008 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3009 ** database connections for the meaning of "modify" in this paragraph. 3010 ** 3011 */ 3012 SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 3013 3014 /* 3015 ** CAPI3REF: Opening A New Database Connection 3016 ** CONSTRUCTOR: sqlite3 3017 ** 3018 ** ^These routines open an SQLite database file as specified by the 3019 ** filename argument. ^The filename argument is interpreted as UTF-8 for 3020 ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 3021 ** order for sqlite3_open16(). ^(A [database connection] handle is usually 3022 ** returned in *ppDb, even if an error occurs. The only exception is that 3023 ** if SQLite is unable to allocate memory to hold the [sqlite3] object, 3024 ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 3025 ** object.)^ ^(If the database is opened (and/or created) successfully, then 3026 ** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 3027 ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 3028 ** an English language description of the error following a failure of any 3029 ** of the sqlite3_open() routines. 3030 ** 3031 ** ^The default encoding will be UTF-8 for databases created using 3032 ** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases 3033 ** created using sqlite3_open16() will be UTF-16 in the native byte order. 3034 ** 3035 ** Whether or not an error occurs when it is opened, resources 3036 ** associated with the [database connection] handle should be released by 3037 ** passing it to [sqlite3_close()] when it is no longer required. 3038 ** 3039 ** The sqlite3_open_v2() interface works like sqlite3_open() 3040 ** except that it accepts two additional parameters for additional control 3041 ** over the new database connection. ^(The flags parameter to 3042 ** sqlite3_open_v2() can take one of 3043 ** the following three values, optionally combined with the 3044 ** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 3045 ** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 3046 ** 3047 ** <dl> 3048 ** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 3049 ** <dd>The database is opened in read-only mode. If the database does not 3050 ** already exist, an error is returned.</dd>)^ 3051 ** 3052 ** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 3053 ** <dd>The database is opened for reading and writing if possible, or reading 3054 ** only if the file is write protected by the operating system. In either 3055 ** case the database must already exist, otherwise an error is returned.</dd>)^ 3056 ** 3057 ** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 3058 ** <dd>The database is opened for reading and writing, and is created if 3059 ** it does not already exist. This is the behavior that is always used for 3060 ** sqlite3_open() and sqlite3_open16().</dd>)^ 3061 ** </dl> 3062 ** 3063 ** If the 3rd parameter to sqlite3_open_v2() is not one of the 3064 ** combinations shown above optionally combined with other 3065 ** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 3066 ** then the behavior is undefined. 3067 ** 3068 ** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 3069 ** opens in the multi-thread [threading mode] as long as the single-thread 3070 ** mode has not been set at compile-time or start-time. ^If the 3071 ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 3072 ** in the serialized [threading mode] unless single-thread was 3073 ** previously selected at compile-time or start-time. 3074 ** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 3075 ** eligible to use [shared cache mode], regardless of whether or not shared 3076 ** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 3077 ** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 3078 ** participate in [shared cache mode] even if it is enabled. 3079 ** 3080 ** ^The fourth parameter to sqlite3_open_v2() is the name of the 3081 ** [sqlite3_vfs] object that defines the operating system interface that 3082 ** the new database connection should use. ^If the fourth parameter is 3083 ** a NULL pointer then the default [sqlite3_vfs] object is used. 3084 ** 3085 ** ^If the filename is ":memory:", then a private, temporary in-memory database 3086 ** is created for the connection. ^This in-memory database will vanish when 3087 ** the database connection is closed. Future versions of SQLite might 3088 ** make use of additional special filenames that begin with the ":" character. 3089 ** It is recommended that when a database filename actually does begin with 3090 ** a ":" character you should prefix the filename with a pathname such as 3091 ** "./" to avoid ambiguity. 3092 ** 3093 ** ^If the filename is an empty string, then a private, temporary 3094 ** on-disk database will be created. ^This private database will be 3095 ** automatically deleted as soon as the database connection is closed. 3096 ** 3097 ** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 3098 ** 3099 ** ^If [URI filename] interpretation is enabled, and the filename argument 3100 ** begins with "file:", then the filename is interpreted as a URI. ^URI 3101 ** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 3102 ** set in the fourth argument to sqlite3_open_v2(), or if it has 3103 ** been enabled globally using the [SQLITE_CONFIG_URI] option with the 3104 ** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 3105 ** As of SQLite version 3.7.7, URI filename interpretation is turned off 3106 ** by default, but future releases of SQLite might enable URI filename 3107 ** interpretation by default. See "[URI filenames]" for additional 3108 ** information. 3109 ** 3110 ** URI filenames are parsed according to RFC 3986. ^If the URI contains an 3111 ** authority, then it must be either an empty string or the string 3112 ** "localhost". ^If the authority is not an empty string or "localhost", an 3113 ** error is returned to the caller. ^The fragment component of a URI, if 3114 ** present, is ignored. 3115 ** 3116 ** ^SQLite uses the path component of the URI as the name of the disk file 3117 ** which contains the database. ^If the path begins with a '/' character, 3118 ** then it is interpreted as an absolute path. ^If the path does not begin 3119 ** with a '/' (meaning that the authority section is omitted from the URI) 3120 ** then the path is interpreted as a relative path. 3121 ** ^(On windows, the first component of an absolute path 3122 ** is a drive specification (e.g. "C:").)^ 3123 ** 3124 ** [[core URI query parameters]] 3125 ** The query component of a URI may contain parameters that are interpreted 3126 ** either by SQLite itself, or by a [VFS | custom VFS implementation]. 3127 ** SQLite and its built-in [VFSes] interpret the 3128 ** following query parameters: 3129 ** 3130 ** <ul> 3131 ** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 3132 ** a VFS object that provides the operating system interface that should 3133 ** be used to access the database file on disk. ^If this option is set to 3134 ** an empty string the default VFS object is used. ^Specifying an unknown 3135 ** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 3136 ** present, then the VFS specified by the option takes precedence over 3137 ** the value passed as the fourth parameter to sqlite3_open_v2(). 3138 ** 3139 ** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 3140 ** "rwc", or "memory". Attempting to set it to any other value is 3141 ** an error)^. 3142 ** ^If "ro" is specified, then the database is opened for read-only 3143 ** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 3144 ** third argument to sqlite3_open_v2(). ^If the mode option is set to 3145 ** "rw", then the database is opened for read-write (but not create) 3146 ** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 3147 ** been set. ^Value "rwc" is equivalent to setting both 3148 ** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 3149 ** set to "memory" then a pure [in-memory database] that never reads 3150 ** or writes from disk is used. ^It is an error to specify a value for 3151 ** the mode parameter that is less restrictive than that specified by 3152 ** the flags passed in the third parameter to sqlite3_open_v2(). 3153 ** 3154 ** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 3155 ** "private". ^Setting it to "shared" is equivalent to setting the 3156 ** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 3157 ** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 3158 ** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 3159 ** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 3160 ** a URI filename, its value overrides any behavior requested by setting 3161 ** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 3162 ** 3163 ** <li> <b>psow</b>: ^The psow parameter indicates whether or not the 3164 ** [powersafe overwrite] property does or does not apply to the 3165 ** storage media on which the database file resides. 3166 ** 3167 ** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter 3168 ** which if set disables file locking in rollback journal modes. This 3169 ** is useful for accessing a database on a filesystem that does not 3170 ** support locking. Caution: Database corruption might result if two 3171 ** or more processes write to the same database and any one of those 3172 ** processes uses nolock=1. 3173 ** 3174 ** <li> <b>immutable</b>: ^The immutable parameter is a boolean query 3175 ** parameter that indicates that the database file is stored on 3176 ** read-only media. ^When immutable is set, SQLite assumes that the 3177 ** database file cannot be changed, even by a process with higher 3178 ** privilege, and so the database is opened read-only and all locking 3179 ** and change detection is disabled. Caution: Setting the immutable 3180 ** property on a database file that does in fact change can result 3181 ** in incorrect query results and/or [SQLITE_CORRUPT] errors. 3182 ** See also: [SQLITE_IOCAP_IMMUTABLE]. 3183 ** 3184 ** </ul> 3185 ** 3186 ** ^Specifying an unknown parameter in the query component of a URI is not an 3187 ** error. Future versions of SQLite might understand additional query 3188 ** parameters. See "[query parameters with special meaning to SQLite]" for 3189 ** additional information. 3190 ** 3191 ** [[URI filename examples]] <h3>URI filename examples</h3> 3192 ** 3193 ** <table border="1" align=center cellpadding=5> 3194 ** <tr><th> URI filenames <th> Results 3195 ** <tr><td> file:data.db <td> 3196 ** Open the file "data.db" in the current directory. 3197 ** <tr><td> file:/home/fred/data.db<br> 3198 ** file:///home/fred/data.db <br> 3199 ** file://localhost/home/fred/data.db <br> <td> 3200 ** Open the database file "/home/fred/data.db". 3201 ** <tr><td> file://darkstar/home/fred/data.db <td> 3202 ** An error. "darkstar" is not a recognized authority. 3203 ** <tr><td style="white-space:nowrap"> 3204 ** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 3205 ** <td> Windows only: Open the file "data.db" on fred's desktop on drive 3206 ** C:. Note that the %20 escaping in this example is not strictly 3207 ** necessary - space characters can be used literally 3208 ** in URI filenames. 3209 ** <tr><td> file:data.db?mode=ro&cache=private <td> 3210 ** Open file "data.db" in the current directory for read-only access. 3211 ** Regardless of whether or not shared-cache mode is enabled by 3212 ** default, use a private cache. 3213 ** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td> 3214 ** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile" 3215 ** that uses dot-files in place of posix advisory locking. 3216 ** <tr><td> file:data.db?mode=readonly <td> 3217 ** An error. "readonly" is not a valid option for the "mode" parameter. 3218 ** </table> 3219 ** 3220 ** ^URI hexadecimal escape sequences (%HH) are supported within the path and 3221 ** query components of a URI. A hexadecimal escape sequence consists of a 3222 ** percent sign - "%" - followed by exactly two hexadecimal digits 3223 ** specifying an octet value. ^Before the path or query components of a 3224 ** URI filename are interpreted, they are encoded using UTF-8 and all 3225 ** hexadecimal escape sequences replaced by a single byte containing the 3226 ** corresponding octet. If this process generates an invalid UTF-8 encoding, 3227 ** the results are undefined. 3228 ** 3229 ** <b>Note to Windows users:</b> The encoding used for the filename argument 3230 ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 3231 ** codepage is currently defined. Filenames containing international 3232 ** characters must be converted to UTF-8 prior to passing them into 3233 ** sqlite3_open() or sqlite3_open_v2(). 3234 ** 3235 ** <b>Note to Windows Runtime users:</b> The temporary directory must be set 3236 ** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various 3237 ** features that require the use of temporary files may fail. 3238 ** 3239 ** See also: [sqlite3_temp_directory] 3240 */ 3241 SQLITE_API int sqlite3_open( 3242 const char *filename, /* Database filename (UTF-8) */ 3243 sqlite3 **ppDb /* OUT: SQLite db handle */ 3244 ); 3245 SQLITE_API int sqlite3_open16( 3246 const void *filename, /* Database filename (UTF-16) */ 3247 sqlite3 **ppDb /* OUT: SQLite db handle */ 3248 ); 3249 SQLITE_API int sqlite3_open_v2( 3250 const char *filename, /* Database filename (UTF-8) */ 3251 sqlite3 **ppDb, /* OUT: SQLite db handle */ 3252 int flags, /* Flags */ 3253 const char *zVfs /* Name of VFS module to use */ 3254 ); 3255 3256 /* 3257 ** CAPI3REF: Obtain Values For URI Parameters 3258 ** 3259 ** These are utility routines, useful to VFS implementations, that check 3260 ** to see if a database file was a URI that contained a specific query 3261 ** parameter, and if so obtains the value of that query parameter. 3262 ** 3263 ** If F is the database filename pointer passed into the xOpen() method of 3264 ** a VFS implementation when the flags parameter to xOpen() has one or 3265 ** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and 3266 ** P is the name of the query parameter, then 3267 ** sqlite3_uri_parameter(F,P) returns the value of the P 3268 ** parameter if it exists or a NULL pointer if P does not appear as a 3269 ** query parameter on F. If P is a query parameter of F 3270 ** has no explicit value, then sqlite3_uri_parameter(F,P) returns 3271 ** a pointer to an empty string. 3272 ** 3273 ** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 3274 ** parameter and returns true (1) or false (0) according to the value 3275 ** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 3276 ** value of query parameter P is one of "yes", "true", or "on" in any 3277 ** case or if the value begins with a non-zero number. The 3278 ** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 3279 ** query parameter P is one of "no", "false", or "off" in any case or 3280 ** if the value begins with a numeric zero. If P is not a query 3281 ** parameter on F or if the value of P is does not match any of the 3282 ** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 3283 ** 3284 ** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 3285 ** 64-bit signed integer and returns that integer, or D if P does not 3286 ** exist. If the value of P is something other than an integer, then 3287 ** zero is returned. 3288 ** 3289 ** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 3290 ** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 3291 ** is not a database file pathname pointer that SQLite passed into the xOpen 3292 ** VFS method, then the behavior of this routine is undefined and probably 3293 ** undesirable. 3294 */ 3295 SQLITE_API const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 3296 SQLITE_API int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 3297 SQLITE_API sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 3298 3299 3300 /* 3301 ** CAPI3REF: Error Codes And Messages 3302 ** METHOD: sqlite3 3303 ** 3304 ** ^If the most recent sqlite3_* API call associated with 3305 ** [database connection] D failed, then the sqlite3_errcode(D) interface 3306 ** returns the numeric [result code] or [extended result code] for that 3307 ** API call. 3308 ** If the most recent API call was successful, 3309 ** then the return value from sqlite3_errcode() is undefined. 3310 ** ^The sqlite3_extended_errcode() 3311 ** interface is the same except that it always returns the 3312 ** [extended result code] even when extended result codes are 3313 ** disabled. 3314 ** 3315 ** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 3316 ** text that describes the error, as either UTF-8 or UTF-16 respectively. 3317 ** ^(Memory to hold the error message string is managed internally. 3318 ** The application does not need to worry about freeing the result. 3319 ** However, the error string might be overwritten or deallocated by 3320 ** subsequent calls to other SQLite interface functions.)^ 3321 ** 3322 ** ^The sqlite3_errstr() interface returns the English-language text 3323 ** that describes the [result code], as UTF-8. 3324 ** ^(Memory to hold the error message string is managed internally 3325 ** and must not be freed by the application)^. 3326 ** 3327 ** When the serialized [threading mode] is in use, it might be the 3328 ** case that a second error occurs on a separate thread in between 3329 ** the time of the first error and the call to these interfaces. 3330 ** When that happens, the second error will be reported since these 3331 ** interfaces always report the most recent result. To avoid 3332 ** this, each thread can obtain exclusive use of the [database connection] D 3333 ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 3334 ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 3335 ** all calls to the interfaces listed here are completed. 3336 ** 3337 ** If an interface fails with SQLITE_MISUSE, that means the interface 3338 ** was invoked incorrectly by the application. In that case, the 3339 ** error code and message may or may not be set. 3340 */ 3341 SQLITE_API int sqlite3_errcode(sqlite3 *db); 3342 SQLITE_API int sqlite3_extended_errcode(sqlite3 *db); 3343 SQLITE_API const char *sqlite3_errmsg(sqlite3*); 3344 SQLITE_API const void *sqlite3_errmsg16(sqlite3*); 3345 SQLITE_API const char *sqlite3_errstr(int); 3346 3347 /* 3348 ** CAPI3REF: Prepared Statement Object 3349 ** KEYWORDS: {prepared statement} {prepared statements} 3350 ** 3351 ** An instance of this object represents a single SQL statement that 3352 ** has been compiled into binary form and is ready to be evaluated. 3353 ** 3354 ** Think of each SQL statement as a separate computer program. The 3355 ** original SQL text is source code. A prepared statement object 3356 ** is the compiled object code. All SQL must be converted into a 3357 ** prepared statement before it can be run. 3358 ** 3359 ** The life-cycle of a prepared statement object usually goes like this: 3360 ** 3361 ** <ol> 3362 ** <li> Create the prepared statement object using [sqlite3_prepare_v2()]. 3363 ** <li> Bind values to [parameters] using the sqlite3_bind_*() 3364 ** interfaces. 3365 ** <li> Run the SQL by calling [sqlite3_step()] one or more times. 3366 ** <li> Reset the prepared statement using [sqlite3_reset()] then go back 3367 ** to step 2. Do this zero or more times. 3368 ** <li> Destroy the object using [sqlite3_finalize()]. 3369 ** </ol> 3370 */ 3371 typedef struct sqlite3_stmt sqlite3_stmt; 3372 3373 /* 3374 ** CAPI3REF: Run-time Limits 3375 ** METHOD: sqlite3 3376 ** 3377 ** ^(This interface allows the size of various constructs to be limited 3378 ** on a connection by connection basis. The first parameter is the 3379 ** [database connection] whose limit is to be set or queried. The 3380 ** second parameter is one of the [limit categories] that define a 3381 ** class of constructs to be size limited. The third parameter is the 3382 ** new limit for that construct.)^ 3383 ** 3384 ** ^If the new limit is a negative number, the limit is unchanged. 3385 ** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 3386 ** [limits | hard upper bound] 3387 ** set at compile-time by a C preprocessor macro called 3388 ** [limits | SQLITE_MAX_<i>NAME</i>]. 3389 ** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 3390 ** ^Attempts to increase a limit above its hard upper bound are 3391 ** silently truncated to the hard upper bound. 3392 ** 3393 ** ^Regardless of whether or not the limit was changed, the 3394 ** [sqlite3_limit()] interface returns the prior value of the limit. 3395 ** ^Hence, to find the current value of a limit without changing it, 3396 ** simply invoke this interface with the third parameter set to -1. 3397 ** 3398 ** Run-time limits are intended for use in applications that manage 3399 ** both their own internal database and also databases that are controlled 3400 ** by untrusted external sources. An example application might be a 3401 ** web browser that has its own databases for storing history and 3402 ** separate databases controlled by JavaScript applications downloaded 3403 ** off the Internet. The internal databases can be given the 3404 ** large, default limits. Databases managed by external sources can 3405 ** be given much smaller limits designed to prevent a denial of service 3406 ** attack. Developers might also want to use the [sqlite3_set_authorizer()] 3407 ** interface to further control untrusted SQL. The size of the database 3408 ** created by an untrusted script can be contained using the 3409 ** [max_page_count] [PRAGMA]. 3410 ** 3411 ** New run-time limit categories may be added in future releases. 3412 */ 3413 SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal); 3414 3415 /* 3416 ** CAPI3REF: Run-Time Limit Categories 3417 ** KEYWORDS: {limit category} {*limit categories} 3418 ** 3419 ** These constants define various performance limits 3420 ** that can be lowered at run-time using [sqlite3_limit()]. 3421 ** The synopsis of the meanings of the various limits is shown below. 3422 ** Additional information is available at [limits | Limits in SQLite]. 3423 ** 3424 ** <dl> 3425 ** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 3426 ** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 3427 ** 3428 ** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 3429 ** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 3430 ** 3431 ** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 3432 ** <dd>The maximum number of columns in a table definition or in the 3433 ** result set of a [SELECT] or the maximum number of columns in an index 3434 ** or in an ORDER BY or GROUP BY clause.</dd>)^ 3435 ** 3436 ** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 3437 ** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 3438 ** 3439 ** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 3440 ** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 3441 ** 3442 ** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 3443 ** <dd>The maximum number of instructions in a virtual machine program 3444 ** used to implement an SQL statement. If [sqlite3_prepare_v2()] or 3445 ** the equivalent tries to allocate space for more than this many opcodes 3446 ** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^ 3447 ** 3448 ** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 3449 ** <dd>The maximum number of arguments on a function.</dd>)^ 3450 ** 3451 ** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 3452 ** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 3453 ** 3454 ** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 3455 ** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 3456 ** <dd>The maximum length of the pattern argument to the [LIKE] or 3457 ** [GLOB] operators.</dd>)^ 3458 ** 3459 ** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 3460 ** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 3461 ** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 3462 ** 3463 ** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 3464 ** <dd>The maximum depth of recursion for triggers.</dd>)^ 3465 ** 3466 ** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt> 3467 ** <dd>The maximum number of auxiliary worker threads that a single 3468 ** [prepared statement] may start.</dd>)^ 3469 ** </dl> 3470 */ 3471 #define SQLITE_LIMIT_LENGTH 0 3472 #define SQLITE_LIMIT_SQL_LENGTH 1 3473 #define SQLITE_LIMIT_COLUMN 2 3474 #define SQLITE_LIMIT_EXPR_DEPTH 3 3475 #define SQLITE_LIMIT_COMPOUND_SELECT 4 3476 #define SQLITE_LIMIT_VDBE_OP 5 3477 #define SQLITE_LIMIT_FUNCTION_ARG 6 3478 #define SQLITE_LIMIT_ATTACHED 7 3479 #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 3480 #define SQLITE_LIMIT_VARIABLE_NUMBER 9 3481 #define SQLITE_LIMIT_TRIGGER_DEPTH 10 3482 #define SQLITE_LIMIT_WORKER_THREADS 11 3483 3484 /* 3485 ** CAPI3REF: Prepare Flags 3486 ** 3487 ** These constants define various flags that can be passed into 3488 ** "prepFlags" parameter of the [sqlite3_prepare_v3()] and 3489 ** [sqlite3_prepare16_v3()] interfaces. 3490 ** 3491 ** New flags may be added in future releases of SQLite. 3492 ** 3493 ** <dl> 3494 ** [[SQLITE_PREPARE_PERSISTENT]] ^(<dt>SQLITE_PREPARE_PERSISTENT</dt> 3495 ** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner 3496 ** that the prepared statement will be retained for a long time and 3497 ** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()] 3498 ** and [sqlite3_prepare16_v3()] assume that the prepared statement will 3499 ** be used just once or at most a few times and then destroyed using 3500 ** [sqlite3_finalize()] relatively soon. The current implementation acts 3501 ** on this hint by avoiding the use of [lookaside memory] so as not to 3502 ** deplete the limited store of lookaside memory. Future versions of 3503 ** SQLite may act on this hint differently. 3504 ** </dl> 3505 */ 3506 #define SQLITE_PREPARE_PERSISTENT 0x01 3507 3508 /* 3509 ** CAPI3REF: Compiling An SQL Statement 3510 ** KEYWORDS: {SQL statement compiler} 3511 ** METHOD: sqlite3 3512 ** CONSTRUCTOR: sqlite3_stmt 3513 ** 3514 ** To execute an SQL statement, it must first be compiled into a byte-code 3515 ** program using one of these routines. Or, in other words, these routines 3516 ** are constructors for the [prepared statement] object. 3517 ** 3518 ** The preferred routine to use is [sqlite3_prepare_v2()]. The 3519 ** [sqlite3_prepare()] interface is legacy and should be avoided. 3520 ** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used 3521 ** for special purposes. 3522 ** 3523 ** The use of the UTF-8 interfaces is preferred, as SQLite currently 3524 ** does all parsing using UTF-8. The UTF-16 interfaces are provided 3525 ** as a convenience. The UTF-16 interfaces work by converting the 3526 ** input text into UTF-8, then invoking the corresponding UTF-8 interface. 3527 ** 3528 ** The first argument, "db", is a [database connection] obtained from a 3529 ** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 3530 ** [sqlite3_open16()]. The database connection must not have been closed. 3531 ** 3532 ** The second argument, "zSql", is the statement to be compiled, encoded 3533 ** as either UTF-8 or UTF-16. The sqlite3_prepare(), sqlite3_prepare_v2(), 3534 ** and sqlite3_prepare_v3() 3535 ** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(), 3536 ** and sqlite3_prepare16_v3() use UTF-16. 3537 ** 3538 ** ^If the nByte argument is negative, then zSql is read up to the 3539 ** first zero terminator. ^If nByte is positive, then it is the 3540 ** number of bytes read from zSql. ^If nByte is zero, then no prepared 3541 ** statement is generated. 3542 ** If the caller knows that the supplied string is nul-terminated, then 3543 ** there is a small performance advantage to passing an nByte parameter that 3544 ** is the number of bytes in the input string <i>including</i> 3545 ** the nul-terminator. 3546 ** 3547 ** ^If pzTail is not NULL then *pzTail is made to point to the first byte 3548 ** past the end of the first SQL statement in zSql. These routines only 3549 ** compile the first statement in zSql, so *pzTail is left pointing to 3550 ** what remains uncompiled. 3551 ** 3552 ** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 3553 ** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 3554 ** to NULL. ^If the input text contains no SQL (if the input is an empty 3555 ** string or a comment) then *ppStmt is set to NULL. 3556 ** The calling procedure is responsible for deleting the compiled 3557 ** SQL statement using [sqlite3_finalize()] after it has finished with it. 3558 ** ppStmt may not be NULL. 3559 ** 3560 ** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 3561 ** otherwise an [error code] is returned. 3562 ** 3563 ** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(), 3564 ** and sqlite3_prepare16_v3() interfaces are recommended for all new programs. 3565 ** The older interfaces (sqlite3_prepare() and sqlite3_prepare16()) 3566 ** are retained for backwards compatibility, but their use is discouraged. 3567 ** ^In the "vX" interfaces, the prepared statement 3568 ** that is returned (the [sqlite3_stmt] object) contains a copy of the 3569 ** original SQL text. This causes the [sqlite3_step()] interface to 3570 ** behave differently in three ways: 3571 ** 3572 ** <ol> 3573 ** <li> 3574 ** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 3575 ** always used to do, [sqlite3_step()] will automatically recompile the SQL 3576 ** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY] 3577 ** retries will occur before sqlite3_step() gives up and returns an error. 3578 ** </li> 3579 ** 3580 ** <li> 3581 ** ^When an error occurs, [sqlite3_step()] will return one of the detailed 3582 ** [error codes] or [extended error codes]. ^The legacy behavior was that 3583 ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 3584 ** and the application would have to make a second call to [sqlite3_reset()] 3585 ** in order to find the underlying cause of the problem. With the "v2" prepare 3586 ** interfaces, the underlying reason for the error is returned immediately. 3587 ** </li> 3588 ** 3589 ** <li> 3590 ** ^If the specific value bound to [parameter | host parameter] in the 3591 ** WHERE clause might influence the choice of query plan for a statement, 3592 ** then the statement will be automatically recompiled, as if there had been 3593 ** a schema change, on the first [sqlite3_step()] call following any change 3594 ** to the [sqlite3_bind_text | bindings] of that [parameter]. 3595 ** ^The specific value of WHERE-clause [parameter] might influence the 3596 ** choice of query plan if the parameter is the left-hand side of a [LIKE] 3597 ** or [GLOB] operator or if the parameter is compared to an indexed column 3598 ** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled. 3599 ** </li> 3600 ** 3601 ** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having 3602 ** the extra prepFlags parameter, which is a bit array consisting of zero or 3603 ** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags. ^The 3604 ** sqlite3_prepare_v2() interface works exactly the same as 3605 ** sqlite3_prepare_v3() with a zero prepFlags parameter. 3606 ** </ol> 3607 */ 3608 SQLITE_API int sqlite3_prepare( 3609 sqlite3 *db, /* Database handle */ 3610 const char *zSql, /* SQL statement, UTF-8 encoded */ 3611 int nByte, /* Maximum length of zSql in bytes. */ 3612 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3613 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3614 ); 3615 SQLITE_API int sqlite3_prepare_v2( 3616 sqlite3 *db, /* Database handle */ 3617 const char *zSql, /* SQL statement, UTF-8 encoded */ 3618 int nByte, /* Maximum length of zSql in bytes. */ 3619 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3620 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3621 ); 3622 SQLITE_API int sqlite3_prepare_v3( 3623 sqlite3 *db, /* Database handle */ 3624 const char *zSql, /* SQL statement, UTF-8 encoded */ 3625 int nByte, /* Maximum length of zSql in bytes. */ 3626 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 3627 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3628 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3629 ); 3630 SQLITE_API int sqlite3_prepare16( 3631 sqlite3 *db, /* Database handle */ 3632 const void *zSql, /* SQL statement, UTF-16 encoded */ 3633 int nByte, /* Maximum length of zSql in bytes. */ 3634 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3635 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3636 ); 3637 SQLITE_API int sqlite3_prepare16_v2( 3638 sqlite3 *db, /* Database handle */ 3639 const void *zSql, /* SQL statement, UTF-16 encoded */ 3640 int nByte, /* Maximum length of zSql in bytes. */ 3641 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3642 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3643 ); 3644 SQLITE_API int sqlite3_prepare16_v3( 3645 sqlite3 *db, /* Database handle */ 3646 const void *zSql, /* SQL statement, UTF-16 encoded */ 3647 int nByte, /* Maximum length of zSql in bytes. */ 3648 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 3649 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3650 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3651 ); 3652 3653 /* 3654 ** CAPI3REF: Retrieving Statement SQL 3655 ** METHOD: sqlite3_stmt 3656 ** 3657 ** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8 3658 ** SQL text used to create [prepared statement] P if P was 3659 ** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], 3660 ** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 3661 ** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8 3662 ** string containing the SQL text of prepared statement P with 3663 ** [bound parameters] expanded. 3664 ** 3665 ** ^(For example, if a prepared statement is created using the SQL 3666 ** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345 3667 ** and parameter :xyz is unbound, then sqlite3_sql() will return 3668 ** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql() 3669 ** will return "SELECT 2345,NULL".)^ 3670 ** 3671 ** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory 3672 ** is available to hold the result, or if the result would exceed the 3673 ** the maximum string length determined by the [SQLITE_LIMIT_LENGTH]. 3674 ** 3675 ** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of 3676 ** bound parameter expansions. ^The [SQLITE_OMIT_TRACE] compile-time 3677 ** option causes sqlite3_expanded_sql() to always return NULL. 3678 ** 3679 ** ^The string returned by sqlite3_sql(P) is managed by SQLite and is 3680 ** automatically freed when the prepared statement is finalized. 3681 ** ^The string returned by sqlite3_expanded_sql(P), on the other hand, 3682 ** is obtained from [sqlite3_malloc()] and must be free by the application 3683 ** by passing it to [sqlite3_free()]. 3684 */ 3685 SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt); 3686 SQLITE_API char *sqlite3_expanded_sql(sqlite3_stmt *pStmt); 3687 3688 /* 3689 ** CAPI3REF: Determine If An SQL Statement Writes The Database 3690 ** METHOD: sqlite3_stmt 3691 ** 3692 ** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 3693 ** and only if the [prepared statement] X makes no direct changes to 3694 ** the content of the database file. 3695 ** 3696 ** Note that [application-defined SQL functions] or 3697 ** [virtual tables] might change the database indirectly as a side effect. 3698 ** ^(For example, if an application defines a function "eval()" that 3699 ** calls [sqlite3_exec()], then the following SQL statement would 3700 ** change the database file through side-effects: 3701 ** 3702 ** <blockquote><pre> 3703 ** SELECT eval('DELETE FROM t1') FROM t2; 3704 ** </pre></blockquote> 3705 ** 3706 ** But because the [SELECT] statement does not change the database file 3707 ** directly, sqlite3_stmt_readonly() would still return true.)^ 3708 ** 3709 ** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 3710 ** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 3711 ** since the statements themselves do not actually modify the database but 3712 ** rather they control the timing of when other statements modify the 3713 ** database. ^The [ATTACH] and [DETACH] statements also cause 3714 ** sqlite3_stmt_readonly() to return true since, while those statements 3715 ** change the configuration of a database connection, they do not make 3716 ** changes to the content of the database files on disk. 3717 ** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since 3718 ** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and 3719 ** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so 3720 ** sqlite3_stmt_readonly() returns false for those commands. 3721 */ 3722 SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 3723 3724 /* 3725 ** CAPI3REF: Determine If A Prepared Statement Has Been Reset 3726 ** METHOD: sqlite3_stmt 3727 ** 3728 ** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 3729 ** [prepared statement] S has been stepped at least once using 3730 ** [sqlite3_step(S)] but has neither run to completion (returned 3731 ** [SQLITE_DONE] from [sqlite3_step(S)]) nor 3732 ** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 3733 ** interface returns false if S is a NULL pointer. If S is not a 3734 ** NULL pointer and is not a pointer to a valid [prepared statement] 3735 ** object, then the behavior is undefined and probably undesirable. 3736 ** 3737 ** This interface can be used in combination [sqlite3_next_stmt()] 3738 ** to locate all prepared statements associated with a database 3739 ** connection that are in need of being reset. This can be used, 3740 ** for example, in diagnostic routines to search for prepared 3741 ** statements that are holding a transaction open. 3742 */ 3743 SQLITE_API int sqlite3_stmt_busy(sqlite3_stmt*); 3744 3745 /* 3746 ** CAPI3REF: Dynamically Typed Value Object 3747 ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 3748 ** 3749 ** SQLite uses the sqlite3_value object to represent all values 3750 ** that can be stored in a database table. SQLite uses dynamic typing 3751 ** for the values it stores. ^Values stored in sqlite3_value objects 3752 ** can be integers, floating point values, strings, BLOBs, or NULL. 3753 ** 3754 ** An sqlite3_value object may be either "protected" or "unprotected". 3755 ** Some interfaces require a protected sqlite3_value. Other interfaces 3756 ** will accept either a protected or an unprotected sqlite3_value. 3757 ** Every interface that accepts sqlite3_value arguments specifies 3758 ** whether or not it requires a protected sqlite3_value. The 3759 ** [sqlite3_value_dup()] interface can be used to construct a new 3760 ** protected sqlite3_value from an unprotected sqlite3_value. 3761 ** 3762 ** The terms "protected" and "unprotected" refer to whether or not 3763 ** a mutex is held. An internal mutex is held for a protected 3764 ** sqlite3_value object but no mutex is held for an unprotected 3765 ** sqlite3_value object. If SQLite is compiled to be single-threaded 3766 ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 3767 ** or if SQLite is run in one of reduced mutex modes 3768 ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 3769 ** then there is no distinction between protected and unprotected 3770 ** sqlite3_value objects and they can be used interchangeably. However, 3771 ** for maximum code portability it is recommended that applications 3772 ** still make the distinction between protected and unprotected 3773 ** sqlite3_value objects even when not strictly required. 3774 ** 3775 ** ^The sqlite3_value objects that are passed as parameters into the 3776 ** implementation of [application-defined SQL functions] are protected. 3777 ** ^The sqlite3_value object returned by 3778 ** [sqlite3_column_value()] is unprotected. 3779 ** Unprotected sqlite3_value objects may only be used with 3780 ** [sqlite3_result_value()] and [sqlite3_bind_value()]. 3781 ** The [sqlite3_value_blob | sqlite3_value_type()] family of 3782 ** interfaces require protected sqlite3_value objects. 3783 */ 3784 typedef struct sqlite3_value sqlite3_value; 3785 3786 /* 3787 ** CAPI3REF: SQL Function Context Object 3788 ** 3789 ** The context in which an SQL function executes is stored in an 3790 ** sqlite3_context object. ^A pointer to an sqlite3_context object 3791 ** is always first parameter to [application-defined SQL functions]. 3792 ** The application-defined SQL function implementation will pass this 3793 ** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 3794 ** [sqlite3_aggregate_context()], [sqlite3_user_data()], 3795 ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 3796 ** and/or [sqlite3_set_auxdata()]. 3797 */ 3798 typedef struct sqlite3_context sqlite3_context; 3799 3800 /* 3801 ** CAPI3REF: Binding Values To Prepared Statements 3802 ** KEYWORDS: {host parameter} {host parameters} {host parameter name} 3803 ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 3804 ** METHOD: sqlite3_stmt 3805 ** 3806 ** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 3807 ** literals may be replaced by a [parameter] that matches one of following 3808 ** templates: 3809 ** 3810 ** <ul> 3811 ** <li> ? 3812 ** <li> ?NNN 3813 ** <li> :VVV 3814 ** <li> @VVV 3815 ** <li> $VVV 3816 ** </ul> 3817 ** 3818 ** In the templates above, NNN represents an integer literal, 3819 ** and VVV represents an alphanumeric identifier.)^ ^The values of these 3820 ** parameters (also called "host parameter names" or "SQL parameters") 3821 ** can be set using the sqlite3_bind_*() routines defined here. 3822 ** 3823 ** ^The first argument to the sqlite3_bind_*() routines is always 3824 ** a pointer to the [sqlite3_stmt] object returned from 3825 ** [sqlite3_prepare_v2()] or its variants. 3826 ** 3827 ** ^The second argument is the index of the SQL parameter to be set. 3828 ** ^The leftmost SQL parameter has an index of 1. ^When the same named 3829 ** SQL parameter is used more than once, second and subsequent 3830 ** occurrences have the same index as the first occurrence. 3831 ** ^The index for named parameters can be looked up using the 3832 ** [sqlite3_bind_parameter_index()] API if desired. ^The index 3833 ** for "?NNN" parameters is the value of NNN. 3834 ** ^The NNN value must be between 1 and the [sqlite3_limit()] 3835 ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 3836 ** 3837 ** ^The third argument is the value to bind to the parameter. 3838 ** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3839 ** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter 3840 ** is ignored and the end result is the same as sqlite3_bind_null(). 3841 ** 3842 ** ^(In those routines that have a fourth argument, its value is the 3843 ** number of bytes in the parameter. To be clear: the value is the 3844 ** number of <u>bytes</u> in the value, not the number of characters.)^ 3845 ** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3846 ** is negative, then the length of the string is 3847 ** the number of bytes up to the first zero terminator. 3848 ** If the fourth parameter to sqlite3_bind_blob() is negative, then 3849 ** the behavior is undefined. 3850 ** If a non-negative fourth parameter is provided to sqlite3_bind_text() 3851 ** or sqlite3_bind_text16() or sqlite3_bind_text64() then 3852 ** that parameter must be the byte offset 3853 ** where the NUL terminator would occur assuming the string were NUL 3854 ** terminated. If any NUL characters occur at byte offsets less than 3855 ** the value of the fourth parameter then the resulting string value will 3856 ** contain embedded NULs. The result of expressions involving strings 3857 ** with embedded NULs is undefined. 3858 ** 3859 ** ^The fifth argument to the BLOB and string binding interfaces 3860 ** is a destructor used to dispose of the BLOB or 3861 ** string after SQLite has finished with it. ^The destructor is called 3862 ** to dispose of the BLOB or string even if the call to bind API fails. 3863 ** ^If the fifth argument is 3864 ** the special value [SQLITE_STATIC], then SQLite assumes that the 3865 ** information is in static, unmanaged space and does not need to be freed. 3866 ** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 3867 ** SQLite makes its own private copy of the data immediately, before 3868 ** the sqlite3_bind_*() routine returns. 3869 ** 3870 ** ^The sixth argument to sqlite3_bind_text64() must be one of 3871 ** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE] 3872 ** to specify the encoding of the text in the third parameter. If 3873 ** the sixth argument to sqlite3_bind_text64() is not one of the 3874 ** allowed values shown above, or if the text encoding is different 3875 ** from the encoding specified by the sixth parameter, then the behavior 3876 ** is undefined. 3877 ** 3878 ** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 3879 ** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 3880 ** (just an integer to hold its size) while it is being processed. 3881 ** Zeroblobs are intended to serve as placeholders for BLOBs whose 3882 ** content is later written using 3883 ** [sqlite3_blob_open | incremental BLOB I/O] routines. 3884 ** ^A negative value for the zeroblob results in a zero-length BLOB. 3885 ** 3886 ** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in 3887 ** [prepared statement] S to have an SQL value of NULL, but to also be 3888 ** associated with the pointer P of type T. ^D is either a NULL pointer or 3889 ** a pointer to a destructor function for P. ^SQLite will invoke the 3890 ** destructor D with a single argument of P when it is finished using 3891 ** P. The T parameter should be a static string, preferably a string 3892 ** literal. The sqlite3_bind_pointer() routine is part of the 3893 ** [pointer passing interface] added for SQLite 3.20.0. 3894 ** 3895 ** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 3896 ** for the [prepared statement] or with a prepared statement for which 3897 ** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 3898 ** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 3899 ** routine is passed a [prepared statement] that has been finalized, the 3900 ** result is undefined and probably harmful. 3901 ** 3902 ** ^Bindings are not cleared by the [sqlite3_reset()] routine. 3903 ** ^Unbound parameters are interpreted as NULL. 3904 ** 3905 ** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 3906 ** [error code] if anything goes wrong. 3907 ** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB 3908 ** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or 3909 ** [SQLITE_MAX_LENGTH]. 3910 ** ^[SQLITE_RANGE] is returned if the parameter 3911 ** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 3912 ** 3913 ** See also: [sqlite3_bind_parameter_count()], 3914 ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 3915 */ 3916 SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 3917 SQLITE_API int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64, 3918 void(*)(void*)); 3919 SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double); 3920 SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int); 3921 SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 3922 SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int); 3923 SQLITE_API int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*)); 3924 SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 3925 SQLITE_API int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64, 3926 void(*)(void*), unsigned char encoding); 3927 SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 3928 SQLITE_API int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*)); 3929 SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 3930 SQLITE_API int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64); 3931 3932 /* 3933 ** CAPI3REF: Number Of SQL Parameters 3934 ** METHOD: sqlite3_stmt 3935 ** 3936 ** ^This routine can be used to find the number of [SQL parameters] 3937 ** in a [prepared statement]. SQL parameters are tokens of the 3938 ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 3939 ** placeholders for values that are [sqlite3_bind_blob | bound] 3940 ** to the parameters at a later time. 3941 ** 3942 ** ^(This routine actually returns the index of the largest (rightmost) 3943 ** parameter. For all forms except ?NNN, this will correspond to the 3944 ** number of unique parameters. If parameters of the ?NNN form are used, 3945 ** there may be gaps in the list.)^ 3946 ** 3947 ** See also: [sqlite3_bind_blob|sqlite3_bind()], 3948 ** [sqlite3_bind_parameter_name()], and 3949 ** [sqlite3_bind_parameter_index()]. 3950 */ 3951 SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*); 3952 3953 /* 3954 ** CAPI3REF: Name Of A Host Parameter 3955 ** METHOD: sqlite3_stmt 3956 ** 3957 ** ^The sqlite3_bind_parameter_name(P,N) interface returns 3958 ** the name of the N-th [SQL parameter] in the [prepared statement] P. 3959 ** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 3960 ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 3961 ** respectively. 3962 ** In other words, the initial ":" or "$" or "@" or "?" 3963 ** is included as part of the name.)^ 3964 ** ^Parameters of the form "?" without a following integer have no name 3965 ** and are referred to as "nameless" or "anonymous parameters". 3966 ** 3967 ** ^The first host parameter has an index of 1, not 0. 3968 ** 3969 ** ^If the value N is out of range or if the N-th parameter is 3970 ** nameless, then NULL is returned. ^The returned string is 3971 ** always in UTF-8 encoding even if the named parameter was 3972 ** originally specified as UTF-16 in [sqlite3_prepare16()], 3973 ** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 3974 ** 3975 ** See also: [sqlite3_bind_blob|sqlite3_bind()], 3976 ** [sqlite3_bind_parameter_count()], and 3977 ** [sqlite3_bind_parameter_index()]. 3978 */ 3979 SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 3980 3981 /* 3982 ** CAPI3REF: Index Of A Parameter With A Given Name 3983 ** METHOD: sqlite3_stmt 3984 ** 3985 ** ^Return the index of an SQL parameter given its name. ^The 3986 ** index value returned is suitable for use as the second 3987 ** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 3988 ** is returned if no matching parameter is found. ^The parameter 3989 ** name must be given in UTF-8 even if the original statement 3990 ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or 3991 ** [sqlite3_prepare16_v3()]. 3992 ** 3993 ** See also: [sqlite3_bind_blob|sqlite3_bind()], 3994 ** [sqlite3_bind_parameter_count()], and 3995 ** [sqlite3_bind_parameter_name()]. 3996 */ 3997 SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 3998 3999 /* 4000 ** CAPI3REF: Reset All Bindings On A Prepared Statement 4001 ** METHOD: sqlite3_stmt 4002 ** 4003 ** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 4004 ** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 4005 ** ^Use this routine to reset all host parameters to NULL. 4006 */ 4007 SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*); 4008 4009 /* 4010 ** CAPI3REF: Number Of Columns In A Result Set 4011 ** METHOD: sqlite3_stmt 4012 ** 4013 ** ^Return the number of columns in the result set returned by the 4014 ** [prepared statement]. ^If this routine returns 0, that means the 4015 ** [prepared statement] returns no data (for example an [UPDATE]). 4016 ** ^However, just because this routine returns a positive number does not 4017 ** mean that one or more rows of data will be returned. ^A SELECT statement 4018 ** will always have a positive sqlite3_column_count() but depending on the 4019 ** WHERE clause constraints and the table content, it might return no rows. 4020 ** 4021 ** See also: [sqlite3_data_count()] 4022 */ 4023 SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt); 4024 4025 /* 4026 ** CAPI3REF: Column Names In A Result Set 4027 ** METHOD: sqlite3_stmt 4028 ** 4029 ** ^These routines return the name assigned to a particular column 4030 ** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 4031 ** interface returns a pointer to a zero-terminated UTF-8 string 4032 ** and sqlite3_column_name16() returns a pointer to a zero-terminated 4033 ** UTF-16 string. ^The first parameter is the [prepared statement] 4034 ** that implements the [SELECT] statement. ^The second parameter is the 4035 ** column number. ^The leftmost column is number 0. 4036 ** 4037 ** ^The returned string pointer is valid until either the [prepared statement] 4038 ** is destroyed by [sqlite3_finalize()] or until the statement is automatically 4039 ** reprepared by the first call to [sqlite3_step()] for a particular run 4040 ** or until the next call to 4041 ** sqlite3_column_name() or sqlite3_column_name16() on the same column. 4042 ** 4043 ** ^If sqlite3_malloc() fails during the processing of either routine 4044 ** (for example during a conversion from UTF-8 to UTF-16) then a 4045 ** NULL pointer is returned. 4046 ** 4047 ** ^The name of a result column is the value of the "AS" clause for 4048 ** that column, if there is an AS clause. If there is no AS clause 4049 ** then the name of the column is unspecified and may change from 4050 ** one release of SQLite to the next. 4051 */ 4052 SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N); 4053 SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N); 4054 4055 /* 4056 ** CAPI3REF: Source Of Data In A Query Result 4057 ** METHOD: sqlite3_stmt 4058 ** 4059 ** ^These routines provide a means to determine the database, table, and 4060 ** table column that is the origin of a particular result column in 4061 ** [SELECT] statement. 4062 ** ^The name of the database or table or column can be returned as 4063 ** either a UTF-8 or UTF-16 string. ^The _database_ routines return 4064 ** the database name, the _table_ routines return the table name, and 4065 ** the origin_ routines return the column name. 4066 ** ^The returned string is valid until the [prepared statement] is destroyed 4067 ** using [sqlite3_finalize()] or until the statement is automatically 4068 ** reprepared by the first call to [sqlite3_step()] for a particular run 4069 ** or until the same information is requested 4070 ** again in a different encoding. 4071 ** 4072 ** ^The names returned are the original un-aliased names of the 4073 ** database, table, and column. 4074 ** 4075 ** ^The first argument to these interfaces is a [prepared statement]. 4076 ** ^These functions return information about the Nth result column returned by 4077 ** the statement, where N is the second function argument. 4078 ** ^The left-most column is column 0 for these routines. 4079 ** 4080 ** ^If the Nth column returned by the statement is an expression or 4081 ** subquery and is not a column value, then all of these functions return 4082 ** NULL. ^These routine might also return NULL if a memory allocation error 4083 ** occurs. ^Otherwise, they return the name of the attached database, table, 4084 ** or column that query result column was extracted from. 4085 ** 4086 ** ^As with all other SQLite APIs, those whose names end with "16" return 4087 ** UTF-16 encoded strings and the other functions return UTF-8. 4088 ** 4089 ** ^These APIs are only available if the library was compiled with the 4090 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 4091 ** 4092 ** If two or more threads call one or more of these routines against the same 4093 ** prepared statement and column at the same time then the results are 4094 ** undefined. 4095 ** 4096 ** If two or more threads call one or more 4097 ** [sqlite3_column_database_name | column metadata interfaces] 4098 ** for the same [prepared statement] and result column 4099 ** at the same time then the results are undefined. 4100 */ 4101 SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int); 4102 SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 4103 SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int); 4104 SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 4105 SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 4106 SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 4107 4108 /* 4109 ** CAPI3REF: Declared Datatype Of A Query Result 4110 ** METHOD: sqlite3_stmt 4111 ** 4112 ** ^(The first parameter is a [prepared statement]. 4113 ** If this statement is a [SELECT] statement and the Nth column of the 4114 ** returned result set of that [SELECT] is a table column (not an 4115 ** expression or subquery) then the declared type of the table 4116 ** column is returned.)^ ^If the Nth column of the result set is an 4117 ** expression or subquery, then a NULL pointer is returned. 4118 ** ^The returned string is always UTF-8 encoded. 4119 ** 4120 ** ^(For example, given the database schema: 4121 ** 4122 ** CREATE TABLE t1(c1 VARIANT); 4123 ** 4124 ** and the following statement to be compiled: 4125 ** 4126 ** SELECT c1 + 1, c1 FROM t1; 4127 ** 4128 ** this routine would return the string "VARIANT" for the second result 4129 ** column (i==1), and a NULL pointer for the first result column (i==0).)^ 4130 ** 4131 ** ^SQLite uses dynamic run-time typing. ^So just because a column 4132 ** is declared to contain a particular type does not mean that the 4133 ** data stored in that column is of the declared type. SQLite is 4134 ** strongly typed, but the typing is dynamic not static. ^Type 4135 ** is associated with individual values, not with the containers 4136 ** used to hold those values. 4137 */ 4138 SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int); 4139 SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 4140 4141 /* 4142 ** CAPI3REF: Evaluate An SQL Statement 4143 ** METHOD: sqlite3_stmt 4144 ** 4145 ** After a [prepared statement] has been prepared using any of 4146 ** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()], 4147 ** or [sqlite3_prepare16_v3()] or one of the legacy 4148 ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 4149 ** must be called one or more times to evaluate the statement. 4150 ** 4151 ** The details of the behavior of the sqlite3_step() interface depend 4152 ** on whether the statement was prepared using the newer "vX" interfaces 4153 ** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()], 4154 ** [sqlite3_prepare16_v2()] or the older legacy 4155 ** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 4156 ** new "vX" interface is recommended for new applications but the legacy 4157 ** interface will continue to be supported. 4158 ** 4159 ** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 4160 ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 4161 ** ^With the "v2" interface, any of the other [result codes] or 4162 ** [extended result codes] might be returned as well. 4163 ** 4164 ** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 4165 ** database locks it needs to do its job. ^If the statement is a [COMMIT] 4166 ** or occurs outside of an explicit transaction, then you can retry the 4167 ** statement. If the statement is not a [COMMIT] and occurs within an 4168 ** explicit transaction then you should rollback the transaction before 4169 ** continuing. 4170 ** 4171 ** ^[SQLITE_DONE] means that the statement has finished executing 4172 ** successfully. sqlite3_step() should not be called again on this virtual 4173 ** machine without first calling [sqlite3_reset()] to reset the virtual 4174 ** machine back to its initial state. 4175 ** 4176 ** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 4177 ** is returned each time a new row of data is ready for processing by the 4178 ** caller. The values may be accessed using the [column access functions]. 4179 ** sqlite3_step() is called again to retrieve the next row of data. 4180 ** 4181 ** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 4182 ** violation) has occurred. sqlite3_step() should not be called again on 4183 ** the VM. More information may be found by calling [sqlite3_errmsg()]. 4184 ** ^With the legacy interface, a more specific error code (for example, 4185 ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 4186 ** can be obtained by calling [sqlite3_reset()] on the 4187 ** [prepared statement]. ^In the "v2" interface, 4188 ** the more specific error code is returned directly by sqlite3_step(). 4189 ** 4190 ** [SQLITE_MISUSE] means that the this routine was called inappropriately. 4191 ** Perhaps it was called on a [prepared statement] that has 4192 ** already been [sqlite3_finalize | finalized] or on one that had 4193 ** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 4194 ** be the case that the same database connection is being used by two or 4195 ** more threads at the same moment in time. 4196 ** 4197 ** For all versions of SQLite up to and including 3.6.23.1, a call to 4198 ** [sqlite3_reset()] was required after sqlite3_step() returned anything 4199 ** other than [SQLITE_ROW] before any subsequent invocation of 4200 ** sqlite3_step(). Failure to reset the prepared statement using 4201 ** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 4202 ** sqlite3_step(). But after [version 3.6.23.1] ([dateof:3.6.23.1]), 4203 ** sqlite3_step() began 4204 ** calling [sqlite3_reset()] automatically in this circumstance rather 4205 ** than returning [SQLITE_MISUSE]. This is not considered a compatibility 4206 ** break because any application that ever receives an SQLITE_MISUSE error 4207 ** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 4208 ** can be used to restore the legacy behavior. 4209 ** 4210 ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 4211 ** API always returns a generic error code, [SQLITE_ERROR], following any 4212 ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 4213 ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 4214 ** specific [error codes] that better describes the error. 4215 ** We admit that this is a goofy design. The problem has been fixed 4216 ** with the "v2" interface. If you prepare all of your SQL statements 4217 ** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()] 4218 ** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead 4219 ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 4220 ** then the more specific [error codes] are returned directly 4221 ** by sqlite3_step(). The use of the "vX" interfaces is recommended. 4222 */ 4223 SQLITE_API int sqlite3_step(sqlite3_stmt*); 4224 4225 /* 4226 ** CAPI3REF: Number of columns in a result set 4227 ** METHOD: sqlite3_stmt 4228 ** 4229 ** ^The sqlite3_data_count(P) interface returns the number of columns in the 4230 ** current row of the result set of [prepared statement] P. 4231 ** ^If prepared statement P does not have results ready to return 4232 ** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 4233 ** interfaces) then sqlite3_data_count(P) returns 0. 4234 ** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 4235 ** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 4236 ** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 4237 ** will return non-zero if previous call to [sqlite3_step](P) returned 4238 ** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 4239 ** where it always returns zero since each step of that multi-step 4240 ** pragma returns 0 columns of data. 4241 ** 4242 ** See also: [sqlite3_column_count()] 4243 */ 4244 SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt); 4245 4246 /* 4247 ** CAPI3REF: Fundamental Datatypes 4248 ** KEYWORDS: SQLITE_TEXT 4249 ** 4250 ** ^(Every value in SQLite has one of five fundamental datatypes: 4251 ** 4252 ** <ul> 4253 ** <li> 64-bit signed integer 4254 ** <li> 64-bit IEEE floating point number 4255 ** <li> string 4256 ** <li> BLOB 4257 ** <li> NULL 4258 ** </ul>)^ 4259 ** 4260 ** These constants are codes for each of those types. 4261 ** 4262 ** Note that the SQLITE_TEXT constant was also used in SQLite version 2 4263 ** for a completely different meaning. Software that links against both 4264 ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 4265 ** SQLITE_TEXT. 4266 */ 4267 #define SQLITE_INTEGER 1 4268 #define SQLITE_FLOAT 2 4269 #define SQLITE_BLOB 4 4270 #define SQLITE_NULL 5 4271 #ifdef SQLITE_TEXT 4272 # undef SQLITE_TEXT 4273 #else 4274 # define SQLITE_TEXT 3 4275 #endif 4276 #define SQLITE3_TEXT 3 4277 4278 /* 4279 ** CAPI3REF: Result Values From A Query 4280 ** KEYWORDS: {column access functions} 4281 ** METHOD: sqlite3_stmt 4282 ** 4283 ** <b>Summary:</b> 4284 ** <blockquote><table border=0 cellpadding=0 cellspacing=0> 4285 ** <tr><td><b>sqlite3_column_blob</b><td>→<td>BLOB result 4286 ** <tr><td><b>sqlite3_column_double</b><td>→<td>REAL result 4287 ** <tr><td><b>sqlite3_column_int</b><td>→<td>32-bit INTEGER result 4288 ** <tr><td><b>sqlite3_column_int64</b><td>→<td>64-bit INTEGER result 4289 ** <tr><td><b>sqlite3_column_text</b><td>→<td>UTF-8 TEXT result 4290 ** <tr><td><b>sqlite3_column_text16</b><td>→<td>UTF-16 TEXT result 4291 ** <tr><td><b>sqlite3_column_value</b><td>→<td>The result as an 4292 ** [sqlite3_value|unprotected sqlite3_value] object. 4293 ** <tr><td> <td> <td> 4294 ** <tr><td><b>sqlite3_column_bytes</b><td>→<td>Size of a BLOB 4295 ** or a UTF-8 TEXT result in bytes 4296 ** <tr><td><b>sqlite3_column_bytes16 </b> 4297 ** <td>→ <td>Size of UTF-16 4298 ** TEXT in bytes 4299 ** <tr><td><b>sqlite3_column_type</b><td>→<td>Default 4300 ** datatype of the result 4301 ** </table></blockquote> 4302 ** 4303 ** <b>Details:</b> 4304 ** 4305 ** ^These routines return information about a single column of the current 4306 ** result row of a query. ^In every case the first argument is a pointer 4307 ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 4308 ** that was returned from [sqlite3_prepare_v2()] or one of its variants) 4309 ** and the second argument is the index of the column for which information 4310 ** should be returned. ^The leftmost column of the result set has the index 0. 4311 ** ^The number of columns in the result can be determined using 4312 ** [sqlite3_column_count()]. 4313 ** 4314 ** If the SQL statement does not currently point to a valid row, or if the 4315 ** column index is out of range, the result is undefined. 4316 ** These routines may only be called when the most recent call to 4317 ** [sqlite3_step()] has returned [SQLITE_ROW] and neither 4318 ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 4319 ** If any of these routines are called after [sqlite3_reset()] or 4320 ** [sqlite3_finalize()] or after [sqlite3_step()] has returned 4321 ** something other than [SQLITE_ROW], the results are undefined. 4322 ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 4323 ** are called from a different thread while any of these routines 4324 ** are pending, then the results are undefined. 4325 ** 4326 ** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16) 4327 ** each return the value of a result column in a specific data format. If 4328 ** the result column is not initially in the requested format (for example, 4329 ** if the query returns an integer but the sqlite3_column_text() interface 4330 ** is used to extract the value) then an automatic type conversion is performed. 4331 ** 4332 ** ^The sqlite3_column_type() routine returns the 4333 ** [SQLITE_INTEGER | datatype code] for the initial data type 4334 ** of the result column. ^The returned value is one of [SQLITE_INTEGER], 4335 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. 4336 ** The return value of sqlite3_column_type() can be used to decide which 4337 ** of the first six interface should be used to extract the column value. 4338 ** The value returned by sqlite3_column_type() is only meaningful if no 4339 ** automatic type conversions have occurred for the value in question. 4340 ** After a type conversion, the result of calling sqlite3_column_type() 4341 ** is undefined, though harmless. Future 4342 ** versions of SQLite may change the behavior of sqlite3_column_type() 4343 ** following a type conversion. 4344 ** 4345 ** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes() 4346 ** or sqlite3_column_bytes16() interfaces can be used to determine the size 4347 ** of that BLOB or string. 4348 ** 4349 ** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 4350 ** routine returns the number of bytes in that BLOB or string. 4351 ** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 4352 ** the string to UTF-8 and then returns the number of bytes. 4353 ** ^If the result is a numeric value then sqlite3_column_bytes() uses 4354 ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 4355 ** the number of bytes in that string. 4356 ** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 4357 ** 4358 ** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 4359 ** routine returns the number of bytes in that BLOB or string. 4360 ** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 4361 ** the string to UTF-16 and then returns the number of bytes. 4362 ** ^If the result is a numeric value then sqlite3_column_bytes16() uses 4363 ** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 4364 ** the number of bytes in that string. 4365 ** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 4366 ** 4367 ** ^The values returned by [sqlite3_column_bytes()] and 4368 ** [sqlite3_column_bytes16()] do not include the zero terminators at the end 4369 ** of the string. ^For clarity: the values returned by 4370 ** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 4371 ** bytes in the string, not the number of characters. 4372 ** 4373 ** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 4374 ** even empty strings, are always zero-terminated. ^The return 4375 ** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 4376 ** 4377 ** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an 4378 ** [unprotected sqlite3_value] object. In a multithreaded environment, 4379 ** an unprotected sqlite3_value object may only be used safely with 4380 ** [sqlite3_bind_value()] and [sqlite3_result_value()]. 4381 ** If the [unprotected sqlite3_value] object returned by 4382 ** [sqlite3_column_value()] is used in any other way, including calls 4383 ** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 4384 ** or [sqlite3_value_bytes()], the behavior is not threadsafe. 4385 ** Hence, the sqlite3_column_value() interface 4386 ** is normally only useful within the implementation of 4387 ** [application-defined SQL functions] or [virtual tables], not within 4388 ** top-level application code. 4389 ** 4390 ** The these routines may attempt to convert the datatype of the result. 4391 ** ^For example, if the internal representation is FLOAT and a text result 4392 ** is requested, [sqlite3_snprintf()] is used internally to perform the 4393 ** conversion automatically. ^(The following table details the conversions 4394 ** that are applied: 4395 ** 4396 ** <blockquote> 4397 ** <table border="1"> 4398 ** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 4399 ** 4400 ** <tr><td> NULL <td> INTEGER <td> Result is 0 4401 ** <tr><td> NULL <td> FLOAT <td> Result is 0.0 4402 ** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer 4403 ** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer 4404 ** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 4405 ** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 4406 ** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 4407 ** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER 4408 ** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 4409 ** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB 4410 ** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER 4411 ** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL 4412 ** <tr><td> TEXT <td> BLOB <td> No change 4413 ** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER 4414 ** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL 4415 ** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 4416 ** </table> 4417 ** </blockquote>)^ 4418 ** 4419 ** Note that when type conversions occur, pointers returned by prior 4420 ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 4421 ** sqlite3_column_text16() may be invalidated. 4422 ** Type conversions and pointer invalidations might occur 4423 ** in the following cases: 4424 ** 4425 ** <ul> 4426 ** <li> The initial content is a BLOB and sqlite3_column_text() or 4427 ** sqlite3_column_text16() is called. A zero-terminator might 4428 ** need to be added to the string.</li> 4429 ** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 4430 ** sqlite3_column_text16() is called. The content must be converted 4431 ** to UTF-16.</li> 4432 ** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 4433 ** sqlite3_column_text() is called. The content must be converted 4434 ** to UTF-8.</li> 4435 ** </ul> 4436 ** 4437 ** ^Conversions between UTF-16be and UTF-16le are always done in place and do 4438 ** not invalidate a prior pointer, though of course the content of the buffer 4439 ** that the prior pointer references will have been modified. Other kinds 4440 ** of conversion are done in place when it is possible, but sometimes they 4441 ** are not possible and in those cases prior pointers are invalidated. 4442 ** 4443 ** The safest policy is to invoke these routines 4444 ** in one of the following ways: 4445 ** 4446 ** <ul> 4447 ** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 4448 ** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 4449 ** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 4450 ** </ul> 4451 ** 4452 ** In other words, you should call sqlite3_column_text(), 4453 ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 4454 ** into the desired format, then invoke sqlite3_column_bytes() or 4455 ** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 4456 ** to sqlite3_column_text() or sqlite3_column_blob() with calls to 4457 ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 4458 ** with calls to sqlite3_column_bytes(). 4459 ** 4460 ** ^The pointers returned are valid until a type conversion occurs as 4461 ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 4462 ** [sqlite3_finalize()] is called. ^The memory space used to hold strings 4463 ** and BLOBs is freed automatically. Do not pass the pointers returned 4464 ** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 4465 ** [sqlite3_free()]. 4466 ** 4467 ** ^(If a memory allocation error occurs during the evaluation of any 4468 ** of these routines, a default value is returned. The default value 4469 ** is either the integer 0, the floating point number 0.0, or a NULL 4470 ** pointer. Subsequent calls to [sqlite3_errcode()] will return 4471 ** [SQLITE_NOMEM].)^ 4472 */ 4473 SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 4474 SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol); 4475 SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol); 4476 SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 4477 SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 4478 SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 4479 SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 4480 SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 4481 SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 4482 SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol); 4483 4484 /* 4485 ** CAPI3REF: Destroy A Prepared Statement Object 4486 ** DESTRUCTOR: sqlite3_stmt 4487 ** 4488 ** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 4489 ** ^If the most recent evaluation of the statement encountered no errors 4490 ** or if the statement is never been evaluated, then sqlite3_finalize() returns 4491 ** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 4492 ** sqlite3_finalize(S) returns the appropriate [error code] or 4493 ** [extended error code]. 4494 ** 4495 ** ^The sqlite3_finalize(S) routine can be called at any point during 4496 ** the life cycle of [prepared statement] S: 4497 ** before statement S is ever evaluated, after 4498 ** one or more calls to [sqlite3_reset()], or after any call 4499 ** to [sqlite3_step()] regardless of whether or not the statement has 4500 ** completed execution. 4501 ** 4502 ** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 4503 ** 4504 ** The application must finalize every [prepared statement] in order to avoid 4505 ** resource leaks. It is a grievous error for the application to try to use 4506 ** a prepared statement after it has been finalized. Any use of a prepared 4507 ** statement after it has been finalized can result in undefined and 4508 ** undesirable behavior such as segfaults and heap corruption. 4509 */ 4510 SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt); 4511 4512 /* 4513 ** CAPI3REF: Reset A Prepared Statement Object 4514 ** METHOD: sqlite3_stmt 4515 ** 4516 ** The sqlite3_reset() function is called to reset a [prepared statement] 4517 ** object back to its initial state, ready to be re-executed. 4518 ** ^Any SQL statement variables that had values bound to them using 4519 ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 4520 ** Use [sqlite3_clear_bindings()] to reset the bindings. 4521 ** 4522 ** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 4523 ** back to the beginning of its program. 4524 ** 4525 ** ^If the most recent call to [sqlite3_step(S)] for the 4526 ** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 4527 ** or if [sqlite3_step(S)] has never before been called on S, 4528 ** then [sqlite3_reset(S)] returns [SQLITE_OK]. 4529 ** 4530 ** ^If the most recent call to [sqlite3_step(S)] for the 4531 ** [prepared statement] S indicated an error, then 4532 ** [sqlite3_reset(S)] returns an appropriate [error code]. 4533 ** 4534 ** ^The [sqlite3_reset(S)] interface does not change the values 4535 ** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 4536 */ 4537 SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt); 4538 4539 /* 4540 ** CAPI3REF: Create Or Redefine SQL Functions 4541 ** KEYWORDS: {function creation routines} 4542 ** KEYWORDS: {application-defined SQL function} 4543 ** KEYWORDS: {application-defined SQL functions} 4544 ** METHOD: sqlite3 4545 ** 4546 ** ^These functions (collectively known as "function creation routines") 4547 ** are used to add SQL functions or aggregates or to redefine the behavior 4548 ** of existing SQL functions or aggregates. The only differences between 4549 ** these routines are the text encoding expected for 4550 ** the second parameter (the name of the function being created) 4551 ** and the presence or absence of a destructor callback for 4552 ** the application data pointer. 4553 ** 4554 ** ^The first parameter is the [database connection] to which the SQL 4555 ** function is to be added. ^If an application uses more than one database 4556 ** connection then application-defined SQL functions must be added 4557 ** to each database connection separately. 4558 ** 4559 ** ^The second parameter is the name of the SQL function to be created or 4560 ** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 4561 ** representation, exclusive of the zero-terminator. ^Note that the name 4562 ** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 4563 ** ^Any attempt to create a function with a longer name 4564 ** will result in [SQLITE_MISUSE] being returned. 4565 ** 4566 ** ^The third parameter (nArg) 4567 ** is the number of arguments that the SQL function or 4568 ** aggregate takes. ^If this parameter is -1, then the SQL function or 4569 ** aggregate may take any number of arguments between 0 and the limit 4570 ** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 4571 ** parameter is less than -1 or greater than 127 then the behavior is 4572 ** undefined. 4573 ** 4574 ** ^The fourth parameter, eTextRep, specifies what 4575 ** [SQLITE_UTF8 | text encoding] this SQL function prefers for 4576 ** its parameters. The application should set this parameter to 4577 ** [SQLITE_UTF16LE] if the function implementation invokes 4578 ** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the 4579 ** implementation invokes [sqlite3_value_text16be()] on an input, or 4580 ** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8] 4581 ** otherwise. ^The same SQL function may be registered multiple times using 4582 ** different preferred text encodings, with different implementations for 4583 ** each encoding. 4584 ** ^When multiple implementations of the same function are available, SQLite 4585 ** will pick the one that involves the least amount of data conversion. 4586 ** 4587 ** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC] 4588 ** to signal that the function will always return the same result given 4589 ** the same inputs within a single SQL statement. Most SQL functions are 4590 ** deterministic. The built-in [random()] SQL function is an example of a 4591 ** function that is not deterministic. The SQLite query planner is able to 4592 ** perform additional optimizations on deterministic functions, so use 4593 ** of the [SQLITE_DETERMINISTIC] flag is recommended where possible. 4594 ** 4595 ** ^(The fifth parameter is an arbitrary pointer. The implementation of the 4596 ** function can gain access to this pointer using [sqlite3_user_data()].)^ 4597 ** 4598 ** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are 4599 ** pointers to C-language functions that implement the SQL function or 4600 ** aggregate. ^A scalar SQL function requires an implementation of the xFunc 4601 ** callback only; NULL pointers must be passed as the xStep and xFinal 4602 ** parameters. ^An aggregate SQL function requires an implementation of xStep 4603 ** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 4604 ** SQL function or aggregate, pass NULL pointers for all three function 4605 ** callbacks. 4606 ** 4607 ** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL, 4608 ** then it is destructor for the application data pointer. 4609 ** The destructor is invoked when the function is deleted, either by being 4610 ** overloaded or when the database connection closes.)^ 4611 ** ^The destructor is also invoked if the call to 4612 ** sqlite3_create_function_v2() fails. 4613 ** ^When the destructor callback of the tenth parameter is invoked, it 4614 ** is passed a single argument which is a copy of the application data 4615 ** pointer which was the fifth parameter to sqlite3_create_function_v2(). 4616 ** 4617 ** ^It is permitted to register multiple implementations of the same 4618 ** functions with the same name but with either differing numbers of 4619 ** arguments or differing preferred text encodings. ^SQLite will use 4620 ** the implementation that most closely matches the way in which the 4621 ** SQL function is used. ^A function implementation with a non-negative 4622 ** nArg parameter is a better match than a function implementation with 4623 ** a negative nArg. ^A function where the preferred text encoding 4624 ** matches the database encoding is a better 4625 ** match than a function where the encoding is different. 4626 ** ^A function where the encoding difference is between UTF16le and UTF16be 4627 ** is a closer match than a function where the encoding difference is 4628 ** between UTF8 and UTF16. 4629 ** 4630 ** ^Built-in functions may be overloaded by new application-defined functions. 4631 ** 4632 ** ^An application-defined function is permitted to call other 4633 ** SQLite interfaces. However, such calls must not 4634 ** close the database connection nor finalize or reset the prepared 4635 ** statement in which the function is running. 4636 */ 4637 SQLITE_API int sqlite3_create_function( 4638 sqlite3 *db, 4639 const char *zFunctionName, 4640 int nArg, 4641 int eTextRep, 4642 void *pApp, 4643 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4644 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4645 void (*xFinal)(sqlite3_context*) 4646 ); 4647 SQLITE_API int sqlite3_create_function16( 4648 sqlite3 *db, 4649 const void *zFunctionName, 4650 int nArg, 4651 int eTextRep, 4652 void *pApp, 4653 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4654 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4655 void (*xFinal)(sqlite3_context*) 4656 ); 4657 SQLITE_API int sqlite3_create_function_v2( 4658 sqlite3 *db, 4659 const char *zFunctionName, 4660 int nArg, 4661 int eTextRep, 4662 void *pApp, 4663 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4664 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4665 void (*xFinal)(sqlite3_context*), 4666 void(*xDestroy)(void*) 4667 ); 4668 4669 /* 4670 ** CAPI3REF: Text Encodings 4671 ** 4672 ** These constant define integer codes that represent the various 4673 ** text encodings supported by SQLite. 4674 */ 4675 #define SQLITE_UTF8 1 /* IMP: R-37514-35566 */ 4676 #define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */ 4677 #define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */ 4678 #define SQLITE_UTF16 4 /* Use native byte order */ 4679 #define SQLITE_ANY 5 /* Deprecated */ 4680 #define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 4681 4682 /* 4683 ** CAPI3REF: Function Flags 4684 ** 4685 ** These constants may be ORed together with the 4686 ** [SQLITE_UTF8 | preferred text encoding] as the fourth argument 4687 ** to [sqlite3_create_function()], [sqlite3_create_function16()], or 4688 ** [sqlite3_create_function_v2()]. 4689 */ 4690 #define SQLITE_DETERMINISTIC 0x800 4691 4692 /* 4693 ** CAPI3REF: Deprecated Functions 4694 ** DEPRECATED 4695 ** 4696 ** These functions are [deprecated]. In order to maintain 4697 ** backwards compatibility with older code, these functions continue 4698 ** to be supported. However, new applications should avoid 4699 ** the use of these functions. To encourage programmers to avoid 4700 ** these functions, we will not explain what they do. 4701 */ 4702 #ifndef SQLITE_OMIT_DEPRECATED 4703 SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 4704 SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 4705 SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 4706 SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void); 4707 SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 4708 SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int), 4709 void*,sqlite3_int64); 4710 #endif 4711 4712 /* 4713 ** CAPI3REF: Obtaining SQL Values 4714 ** METHOD: sqlite3_value 4715 ** 4716 ** <b>Summary:</b> 4717 ** <blockquote><table border=0 cellpadding=0 cellspacing=0> 4718 ** <tr><td><b>sqlite3_value_blob</b><td>→<td>BLOB value 4719 ** <tr><td><b>sqlite3_value_double</b><td>→<td>REAL value 4720 ** <tr><td><b>sqlite3_value_int</b><td>→<td>32-bit INTEGER value 4721 ** <tr><td><b>sqlite3_value_int64</b><td>→<td>64-bit INTEGER value 4722 ** <tr><td><b>sqlite3_value_pointer</b><td>→<td>Pointer value 4723 ** <tr><td><b>sqlite3_value_text</b><td>→<td>UTF-8 TEXT value 4724 ** <tr><td><b>sqlite3_value_text16</b><td>→<td>UTF-16 TEXT value in 4725 ** the native byteorder 4726 ** <tr><td><b>sqlite3_value_text16be</b><td>→<td>UTF-16be TEXT value 4727 ** <tr><td><b>sqlite3_value_text16le</b><td>→<td>UTF-16le TEXT value 4728 ** <tr><td> <td> <td> 4729 ** <tr><td><b>sqlite3_value_bytes</b><td>→<td>Size of a BLOB 4730 ** or a UTF-8 TEXT in bytes 4731 ** <tr><td><b>sqlite3_value_bytes16 </b> 4732 ** <td>→ <td>Size of UTF-16 4733 ** TEXT in bytes 4734 ** <tr><td><b>sqlite3_value_type</b><td>→<td>Default 4735 ** datatype of the value 4736 ** <tr><td><b>sqlite3_value_numeric_type </b> 4737 ** <td>→ <td>Best numeric datatype of the value 4738 ** </table></blockquote> 4739 ** 4740 ** <b>Details:</b> 4741 ** 4742 ** These routines extract type, size, and content information from 4743 ** [protected sqlite3_value] objects. Protected sqlite3_value objects 4744 ** are used to pass parameter information into implementation of 4745 ** [application-defined SQL functions] and [virtual tables]. 4746 ** 4747 ** These routines work only with [protected sqlite3_value] objects. 4748 ** Any attempt to use these routines on an [unprotected sqlite3_value] 4749 ** is not threadsafe. 4750 ** 4751 ** ^These routines work just like the corresponding [column access functions] 4752 ** except that these routines take a single [protected sqlite3_value] object 4753 ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 4754 ** 4755 ** ^The sqlite3_value_text16() interface extracts a UTF-16 string 4756 ** in the native byte-order of the host machine. ^The 4757 ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 4758 ** extract UTF-16 strings as big-endian and little-endian respectively. 4759 ** 4760 ** ^If [sqlite3_value] object V was initialized 4761 ** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)] 4762 ** and if X and Y are strings that compare equal according to strcmp(X,Y), 4763 ** then sqlite3_value_pointer(V,Y) will return the pointer P. ^Otherwise, 4764 ** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer() 4765 ** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 4766 ** 4767 ** ^(The sqlite3_value_type(V) interface returns the 4768 ** [SQLITE_INTEGER | datatype code] for the initial datatype of the 4769 ** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER], 4770 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^ 4771 ** Other interfaces might change the datatype for an sqlite3_value object. 4772 ** For example, if the datatype is initially SQLITE_INTEGER and 4773 ** sqlite3_value_text(V) is called to extract a text value for that 4774 ** integer, then subsequent calls to sqlite3_value_type(V) might return 4775 ** SQLITE_TEXT. Whether or not a persistent internal datatype conversion 4776 ** occurs is undefined and may change from one release of SQLite to the next. 4777 ** 4778 ** ^(The sqlite3_value_numeric_type() interface attempts to apply 4779 ** numeric affinity to the value. This means that an attempt is 4780 ** made to convert the value to an integer or floating point. If 4781 ** such a conversion is possible without loss of information (in other 4782 ** words, if the value is a string that looks like a number) 4783 ** then the conversion is performed. Otherwise no conversion occurs. 4784 ** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 4785 ** 4786 ** Please pay particular attention to the fact that the pointer returned 4787 ** from [sqlite3_value_blob()], [sqlite3_value_text()], or 4788 ** [sqlite3_value_text16()] can be invalidated by a subsequent call to 4789 ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 4790 ** or [sqlite3_value_text16()]. 4791 ** 4792 ** These routines must be called from the same thread as 4793 ** the SQL function that supplied the [sqlite3_value*] parameters. 4794 */ 4795 SQLITE_API const void *sqlite3_value_blob(sqlite3_value*); 4796 SQLITE_API double sqlite3_value_double(sqlite3_value*); 4797 SQLITE_API int sqlite3_value_int(sqlite3_value*); 4798 SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 4799 SQLITE_API void *sqlite3_value_pointer(sqlite3_value*, const char*); 4800 SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*); 4801 SQLITE_API const void *sqlite3_value_text16(sqlite3_value*); 4802 SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*); 4803 SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*); 4804 SQLITE_API int sqlite3_value_bytes(sqlite3_value*); 4805 SQLITE_API int sqlite3_value_bytes16(sqlite3_value*); 4806 SQLITE_API int sqlite3_value_type(sqlite3_value*); 4807 SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*); 4808 4809 /* 4810 ** CAPI3REF: Finding The Subtype Of SQL Values 4811 ** METHOD: sqlite3_value 4812 ** 4813 ** The sqlite3_value_subtype(V) function returns the subtype for 4814 ** an [application-defined SQL function] argument V. The subtype 4815 ** information can be used to pass a limited amount of context from 4816 ** one SQL function to another. Use the [sqlite3_result_subtype()] 4817 ** routine to set the subtype for the return value of an SQL function. 4818 */ 4819 SQLITE_API unsigned int sqlite3_value_subtype(sqlite3_value*); 4820 4821 /* 4822 ** CAPI3REF: Copy And Free SQL Values 4823 ** METHOD: sqlite3_value 4824 ** 4825 ** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value] 4826 ** object D and returns a pointer to that copy. ^The [sqlite3_value] returned 4827 ** is a [protected sqlite3_value] object even if the input is not. 4828 ** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a 4829 ** memory allocation fails. 4830 ** 4831 ** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object 4832 ** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer 4833 ** then sqlite3_value_free(V) is a harmless no-op. 4834 */ 4835 SQLITE_API sqlite3_value *sqlite3_value_dup(const sqlite3_value*); 4836 SQLITE_API void sqlite3_value_free(sqlite3_value*); 4837 4838 /* 4839 ** CAPI3REF: Obtain Aggregate Function Context 4840 ** METHOD: sqlite3_context 4841 ** 4842 ** Implementations of aggregate SQL functions use this 4843 ** routine to allocate memory for storing their state. 4844 ** 4845 ** ^The first time the sqlite3_aggregate_context(C,N) routine is called 4846 ** for a particular aggregate function, SQLite 4847 ** allocates N of memory, zeroes out that memory, and returns a pointer 4848 ** to the new memory. ^On second and subsequent calls to 4849 ** sqlite3_aggregate_context() for the same aggregate function instance, 4850 ** the same buffer is returned. Sqlite3_aggregate_context() is normally 4851 ** called once for each invocation of the xStep callback and then one 4852 ** last time when the xFinal callback is invoked. ^(When no rows match 4853 ** an aggregate query, the xStep() callback of the aggregate function 4854 ** implementation is never called and xFinal() is called exactly once. 4855 ** In those cases, sqlite3_aggregate_context() might be called for the 4856 ** first time from within xFinal().)^ 4857 ** 4858 ** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 4859 ** when first called if N is less than or equal to zero or if a memory 4860 ** allocate error occurs. 4861 ** 4862 ** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 4863 ** determined by the N parameter on first successful call. Changing the 4864 ** value of N in subsequent call to sqlite3_aggregate_context() within 4865 ** the same aggregate function instance will not resize the memory 4866 ** allocation.)^ Within the xFinal callback, it is customary to set 4867 ** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 4868 ** pointless memory allocations occur. 4869 ** 4870 ** ^SQLite automatically frees the memory allocated by 4871 ** sqlite3_aggregate_context() when the aggregate query concludes. 4872 ** 4873 ** The first parameter must be a copy of the 4874 ** [sqlite3_context | SQL function context] that is the first parameter 4875 ** to the xStep or xFinal callback routine that implements the aggregate 4876 ** function. 4877 ** 4878 ** This routine must be called from the same thread in which 4879 ** the aggregate SQL function is running. 4880 */ 4881 SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 4882 4883 /* 4884 ** CAPI3REF: User Data For Functions 4885 ** METHOD: sqlite3_context 4886 ** 4887 ** ^The sqlite3_user_data() interface returns a copy of 4888 ** the pointer that was the pUserData parameter (the 5th parameter) 4889 ** of the [sqlite3_create_function()] 4890 ** and [sqlite3_create_function16()] routines that originally 4891 ** registered the application defined function. 4892 ** 4893 ** This routine must be called from the same thread in which 4894 ** the application-defined function is running. 4895 */ 4896 SQLITE_API void *sqlite3_user_data(sqlite3_context*); 4897 4898 /* 4899 ** CAPI3REF: Database Connection For Functions 4900 ** METHOD: sqlite3_context 4901 ** 4902 ** ^The sqlite3_context_db_handle() interface returns a copy of 4903 ** the pointer to the [database connection] (the 1st parameter) 4904 ** of the [sqlite3_create_function()] 4905 ** and [sqlite3_create_function16()] routines that originally 4906 ** registered the application defined function. 4907 */ 4908 SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 4909 4910 /* 4911 ** CAPI3REF: Function Auxiliary Data 4912 ** METHOD: sqlite3_context 4913 ** 4914 ** These functions may be used by (non-aggregate) SQL functions to 4915 ** associate metadata with argument values. If the same value is passed to 4916 ** multiple invocations of the same SQL function during query execution, under 4917 ** some circumstances the associated metadata may be preserved. An example 4918 ** of where this might be useful is in a regular-expression matching 4919 ** function. The compiled version of the regular expression can be stored as 4920 ** metadata associated with the pattern string. 4921 ** Then as long as the pattern string remains the same, 4922 ** the compiled regular expression can be reused on multiple 4923 ** invocations of the same function. 4924 ** 4925 ** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the metadata 4926 ** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument 4927 ** value to the application-defined function. ^N is zero for the left-most 4928 ** function argument. ^If there is no metadata 4929 ** associated with the function argument, the sqlite3_get_auxdata(C,N) interface 4930 ** returns a NULL pointer. 4931 ** 4932 ** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th 4933 ** argument of the application-defined function. ^Subsequent 4934 ** calls to sqlite3_get_auxdata(C,N) return P from the most recent 4935 ** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or 4936 ** NULL if the metadata has been discarded. 4937 ** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL, 4938 ** SQLite will invoke the destructor function X with parameter P exactly 4939 ** once, when the metadata is discarded. 4940 ** SQLite is free to discard the metadata at any time, including: <ul> 4941 ** <li> ^(when the corresponding function parameter changes)^, or 4942 ** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the 4943 ** SQL statement)^, or 4944 ** <li> ^(when sqlite3_set_auxdata() is invoked again on the same 4945 ** parameter)^, or 4946 ** <li> ^(during the original sqlite3_set_auxdata() call when a memory 4947 ** allocation error occurs.)^ </ul> 4948 ** 4949 ** Note the last bullet in particular. The destructor X in 4950 ** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the 4951 ** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata() 4952 ** should be called near the end of the function implementation and the 4953 ** function implementation should not make any use of P after 4954 ** sqlite3_set_auxdata() has been called. 4955 ** 4956 ** ^(In practice, metadata is preserved between function calls for 4957 ** function parameters that are compile-time constants, including literal 4958 ** values and [parameters] and expressions composed from the same.)^ 4959 ** 4960 ** The value of the N parameter to these interfaces should be non-negative. 4961 ** Future enhancements may make use of negative N values to define new 4962 ** kinds of function caching behavior. 4963 ** 4964 ** These routines must be called from the same thread in which 4965 ** the SQL function is running. 4966 */ 4967 SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N); 4968 SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 4969 4970 4971 /* 4972 ** CAPI3REF: Constants Defining Special Destructor Behavior 4973 ** 4974 ** These are special values for the destructor that is passed in as the 4975 ** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 4976 ** argument is SQLITE_STATIC, it means that the content pointer is constant 4977 ** and will never change. It does not need to be destroyed. ^The 4978 ** SQLITE_TRANSIENT value means that the content will likely change in 4979 ** the near future and that SQLite should make its own private copy of 4980 ** the content before returning. 4981 ** 4982 ** The typedef is necessary to work around problems in certain 4983 ** C++ compilers. 4984 */ 4985 typedef void (*sqlite3_destructor_type)(void*); 4986 #define SQLITE_STATIC ((sqlite3_destructor_type)0) 4987 #define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 4988 4989 /* 4990 ** CAPI3REF: Setting The Result Of An SQL Function 4991 ** METHOD: sqlite3_context 4992 ** 4993 ** These routines are used by the xFunc or xFinal callbacks that 4994 ** implement SQL functions and aggregates. See 4995 ** [sqlite3_create_function()] and [sqlite3_create_function16()] 4996 ** for additional information. 4997 ** 4998 ** These functions work very much like the [parameter binding] family of 4999 ** functions used to bind values to host parameters in prepared statements. 5000 ** Refer to the [SQL parameter] documentation for additional information. 5001 ** 5002 ** ^The sqlite3_result_blob() interface sets the result from 5003 ** an application-defined function to be the BLOB whose content is pointed 5004 ** to by the second parameter and which is N bytes long where N is the 5005 ** third parameter. 5006 ** 5007 ** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N) 5008 ** interfaces set the result of the application-defined function to be 5009 ** a BLOB containing all zero bytes and N bytes in size. 5010 ** 5011 ** ^The sqlite3_result_double() interface sets the result from 5012 ** an application-defined function to be a floating point value specified 5013 ** by its 2nd argument. 5014 ** 5015 ** ^The sqlite3_result_error() and sqlite3_result_error16() functions 5016 ** cause the implemented SQL function to throw an exception. 5017 ** ^SQLite uses the string pointed to by the 5018 ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 5019 ** as the text of an error message. ^SQLite interprets the error 5020 ** message string from sqlite3_result_error() as UTF-8. ^SQLite 5021 ** interprets the string from sqlite3_result_error16() as UTF-16 in native 5022 ** byte order. ^If the third parameter to sqlite3_result_error() 5023 ** or sqlite3_result_error16() is negative then SQLite takes as the error 5024 ** message all text up through the first zero character. 5025 ** ^If the third parameter to sqlite3_result_error() or 5026 ** sqlite3_result_error16() is non-negative then SQLite takes that many 5027 ** bytes (not characters) from the 2nd parameter as the error message. 5028 ** ^The sqlite3_result_error() and sqlite3_result_error16() 5029 ** routines make a private copy of the error message text before 5030 ** they return. Hence, the calling function can deallocate or 5031 ** modify the text after they return without harm. 5032 ** ^The sqlite3_result_error_code() function changes the error code 5033 ** returned by SQLite as a result of an error in a function. ^By default, 5034 ** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 5035 ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 5036 ** 5037 ** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 5038 ** error indicating that a string or BLOB is too long to represent. 5039 ** 5040 ** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 5041 ** error indicating that a memory allocation failed. 5042 ** 5043 ** ^The sqlite3_result_int() interface sets the return value 5044 ** of the application-defined function to be the 32-bit signed integer 5045 ** value given in the 2nd argument. 5046 ** ^The sqlite3_result_int64() interface sets the return value 5047 ** of the application-defined function to be the 64-bit signed integer 5048 ** value given in the 2nd argument. 5049 ** 5050 ** ^The sqlite3_result_null() interface sets the return value 5051 ** of the application-defined function to be NULL. 5052 ** 5053 ** ^The sqlite3_result_text(), sqlite3_result_text16(), 5054 ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 5055 ** set the return value of the application-defined function to be 5056 ** a text string which is represented as UTF-8, UTF-16 native byte order, 5057 ** UTF-16 little endian, or UTF-16 big endian, respectively. 5058 ** ^The sqlite3_result_text64() interface sets the return value of an 5059 ** application-defined function to be a text string in an encoding 5060 ** specified by the fifth (and last) parameter, which must be one 5061 ** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]. 5062 ** ^SQLite takes the text result from the application from 5063 ** the 2nd parameter of the sqlite3_result_text* interfaces. 5064 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5065 ** is negative, then SQLite takes result text from the 2nd parameter 5066 ** through the first zero character. 5067 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5068 ** is non-negative, then as many bytes (not characters) of the text 5069 ** pointed to by the 2nd parameter are taken as the application-defined 5070 ** function result. If the 3rd parameter is non-negative, then it 5071 ** must be the byte offset into the string where the NUL terminator would 5072 ** appear if the string where NUL terminated. If any NUL characters occur 5073 ** in the string at a byte offset that is less than the value of the 3rd 5074 ** parameter, then the resulting string will contain embedded NULs and the 5075 ** result of expressions operating on strings with embedded NULs is undefined. 5076 ** ^If the 4th parameter to the sqlite3_result_text* interfaces 5077 ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 5078 ** function as the destructor on the text or BLOB result when it has 5079 ** finished using that result. 5080 ** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 5081 ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 5082 ** assumes that the text or BLOB result is in constant space and does not 5083 ** copy the content of the parameter nor call a destructor on the content 5084 ** when it has finished using that result. 5085 ** ^If the 4th parameter to the sqlite3_result_text* interfaces 5086 ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 5087 ** then SQLite makes a copy of the result into space obtained 5088 ** from [sqlite3_malloc()] before it returns. 5089 ** 5090 ** ^The sqlite3_result_value() interface sets the result of 5091 ** the application-defined function to be a copy of the 5092 ** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 5093 ** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 5094 ** so that the [sqlite3_value] specified in the parameter may change or 5095 ** be deallocated after sqlite3_result_value() returns without harm. 5096 ** ^A [protected sqlite3_value] object may always be used where an 5097 ** [unprotected sqlite3_value] object is required, so either 5098 ** kind of [sqlite3_value] object can be used with this interface. 5099 ** 5100 ** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an 5101 ** SQL NULL value, just like [sqlite3_result_null(C)], except that it 5102 ** also associates the host-language pointer P or type T with that 5103 ** NULL value such that the pointer can be retrieved within an 5104 ** [application-defined SQL function] using [sqlite3_value_pointer()]. 5105 ** ^If the D parameter is not NULL, then it is a pointer to a destructor 5106 ** for the P parameter. ^SQLite invokes D with P as its only argument 5107 ** when SQLite is finished with P. The T parameter should be a static 5108 ** string and preferably a string literal. The sqlite3_result_pointer() 5109 ** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 5110 ** 5111 ** If these routines are called from within the different thread 5112 ** than the one containing the application-defined function that received 5113 ** the [sqlite3_context] pointer, the results are undefined. 5114 */ 5115 SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 5116 SQLITE_API void sqlite3_result_blob64(sqlite3_context*,const void*, 5117 sqlite3_uint64,void(*)(void*)); 5118 SQLITE_API void sqlite3_result_double(sqlite3_context*, double); 5119 SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int); 5120 SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int); 5121 SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*); 5122 SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*); 5123 SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int); 5124 SQLITE_API void sqlite3_result_int(sqlite3_context*, int); 5125 SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 5126 SQLITE_API void sqlite3_result_null(sqlite3_context*); 5127 SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 5128 SQLITE_API void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64, 5129 void(*)(void*), unsigned char encoding); 5130 SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 5131 SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 5132 SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 5133 SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 5134 SQLITE_API void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*)); 5135 SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n); 5136 SQLITE_API int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n); 5137 5138 5139 /* 5140 ** CAPI3REF: Setting The Subtype Of An SQL Function 5141 ** METHOD: sqlite3_context 5142 ** 5143 ** The sqlite3_result_subtype(C,T) function causes the subtype of 5144 ** the result from the [application-defined SQL function] with 5145 ** [sqlite3_context] C to be the value T. Only the lower 8 bits 5146 ** of the subtype T are preserved in current versions of SQLite; 5147 ** higher order bits are discarded. 5148 ** The number of subtype bytes preserved by SQLite might increase 5149 ** in future releases of SQLite. 5150 */ 5151 SQLITE_API void sqlite3_result_subtype(sqlite3_context*,unsigned int); 5152 5153 /* 5154 ** CAPI3REF: Define New Collating Sequences 5155 ** METHOD: sqlite3 5156 ** 5157 ** ^These functions add, remove, or modify a [collation] associated 5158 ** with the [database connection] specified as the first argument. 5159 ** 5160 ** ^The name of the collation is a UTF-8 string 5161 ** for sqlite3_create_collation() and sqlite3_create_collation_v2() 5162 ** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 5163 ** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 5164 ** considered to be the same name. 5165 ** 5166 ** ^(The third argument (eTextRep) must be one of the constants: 5167 ** <ul> 5168 ** <li> [SQLITE_UTF8], 5169 ** <li> [SQLITE_UTF16LE], 5170 ** <li> [SQLITE_UTF16BE], 5171 ** <li> [SQLITE_UTF16], or 5172 ** <li> [SQLITE_UTF16_ALIGNED]. 5173 ** </ul>)^ 5174 ** ^The eTextRep argument determines the encoding of strings passed 5175 ** to the collating function callback, xCallback. 5176 ** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 5177 ** force strings to be UTF16 with native byte order. 5178 ** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 5179 ** on an even byte address. 5180 ** 5181 ** ^The fourth argument, pArg, is an application data pointer that is passed 5182 ** through as the first argument to the collating function callback. 5183 ** 5184 ** ^The fifth argument, xCallback, is a pointer to the collating function. 5185 ** ^Multiple collating functions can be registered using the same name but 5186 ** with different eTextRep parameters and SQLite will use whichever 5187 ** function requires the least amount of data transformation. 5188 ** ^If the xCallback argument is NULL then the collating function is 5189 ** deleted. ^When all collating functions having the same name are deleted, 5190 ** that collation is no longer usable. 5191 ** 5192 ** ^The collating function callback is invoked with a copy of the pArg 5193 ** application data pointer and with two strings in the encoding specified 5194 ** by the eTextRep argument. The collating function must return an 5195 ** integer that is negative, zero, or positive 5196 ** if the first string is less than, equal to, or greater than the second, 5197 ** respectively. A collating function must always return the same answer 5198 ** given the same inputs. If two or more collating functions are registered 5199 ** to the same collation name (using different eTextRep values) then all 5200 ** must give an equivalent answer when invoked with equivalent strings. 5201 ** The collating function must obey the following properties for all 5202 ** strings A, B, and C: 5203 ** 5204 ** <ol> 5205 ** <li> If A==B then B==A. 5206 ** <li> If A==B and B==C then A==C. 5207 ** <li> If A<B THEN B>A. 5208 ** <li> If A<B and B<C then A<C. 5209 ** </ol> 5210 ** 5211 ** If a collating function fails any of the above constraints and that 5212 ** collating function is registered and used, then the behavior of SQLite 5213 ** is undefined. 5214 ** 5215 ** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 5216 ** with the addition that the xDestroy callback is invoked on pArg when 5217 ** the collating function is deleted. 5218 ** ^Collating functions are deleted when they are overridden by later 5219 ** calls to the collation creation functions or when the 5220 ** [database connection] is closed using [sqlite3_close()]. 5221 ** 5222 ** ^The xDestroy callback is <u>not</u> called if the 5223 ** sqlite3_create_collation_v2() function fails. Applications that invoke 5224 ** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 5225 ** check the return code and dispose of the application data pointer 5226 ** themselves rather than expecting SQLite to deal with it for them. 5227 ** This is different from every other SQLite interface. The inconsistency 5228 ** is unfortunate but cannot be changed without breaking backwards 5229 ** compatibility. 5230 ** 5231 ** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 5232 */ 5233 SQLITE_API int sqlite3_create_collation( 5234 sqlite3*, 5235 const char *zName, 5236 int eTextRep, 5237 void *pArg, 5238 int(*xCompare)(void*,int,const void*,int,const void*) 5239 ); 5240 SQLITE_API int sqlite3_create_collation_v2( 5241 sqlite3*, 5242 const char *zName, 5243 int eTextRep, 5244 void *pArg, 5245 int(*xCompare)(void*,int,const void*,int,const void*), 5246 void(*xDestroy)(void*) 5247 ); 5248 SQLITE_API int sqlite3_create_collation16( 5249 sqlite3*, 5250 const void *zName, 5251 int eTextRep, 5252 void *pArg, 5253 int(*xCompare)(void*,int,const void*,int,const void*) 5254 ); 5255 5256 /* 5257 ** CAPI3REF: Collation Needed Callbacks 5258 ** METHOD: sqlite3 5259 ** 5260 ** ^To avoid having to register all collation sequences before a database 5261 ** can be used, a single callback function may be registered with the 5262 ** [database connection] to be invoked whenever an undefined collation 5263 ** sequence is required. 5264 ** 5265 ** ^If the function is registered using the sqlite3_collation_needed() API, 5266 ** then it is passed the names of undefined collation sequences as strings 5267 ** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 5268 ** the names are passed as UTF-16 in machine native byte order. 5269 ** ^A call to either function replaces the existing collation-needed callback. 5270 ** 5271 ** ^(When the callback is invoked, the first argument passed is a copy 5272 ** of the second argument to sqlite3_collation_needed() or 5273 ** sqlite3_collation_needed16(). The second argument is the database 5274 ** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 5275 ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 5276 ** sequence function required. The fourth parameter is the name of the 5277 ** required collation sequence.)^ 5278 ** 5279 ** The callback function should register the desired collation using 5280 ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 5281 ** [sqlite3_create_collation_v2()]. 5282 */ 5283 SQLITE_API int sqlite3_collation_needed( 5284 sqlite3*, 5285 void*, 5286 void(*)(void*,sqlite3*,int eTextRep,const char*) 5287 ); 5288 SQLITE_API int sqlite3_collation_needed16( 5289 sqlite3*, 5290 void*, 5291 void(*)(void*,sqlite3*,int eTextRep,const void*) 5292 ); 5293 5294 #ifdef SQLITE_HAS_CODEC 5295 /* 5296 ** Specify the key for an encrypted database. This routine should be 5297 ** called right after sqlite3_open(). 5298 ** 5299 ** The code to implement this API is not available in the public release 5300 ** of SQLite. 5301 */ 5302 SQLITE_API int sqlite3_key( 5303 sqlite3 *db, /* Database to be rekeyed */ 5304 const void *pKey, int nKey /* The key */ 5305 ); 5306 SQLITE_API int sqlite3_key_v2( 5307 sqlite3 *db, /* Database to be rekeyed */ 5308 const char *zDbName, /* Name of the database */ 5309 const void *pKey, int nKey /* The key */ 5310 ); 5311 5312 /* 5313 ** Change the key on an open database. If the current database is not 5314 ** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 5315 ** database is decrypted. 5316 ** 5317 ** The code to implement this API is not available in the public release 5318 ** of SQLite. 5319 */ 5320 SQLITE_API int sqlite3_rekey( 5321 sqlite3 *db, /* Database to be rekeyed */ 5322 const void *pKey, int nKey /* The new key */ 5323 ); 5324 SQLITE_API int sqlite3_rekey_v2( 5325 sqlite3 *db, /* Database to be rekeyed */ 5326 const char *zDbName, /* Name of the database */ 5327 const void *pKey, int nKey /* The new key */ 5328 ); 5329 5330 /* 5331 ** Specify the activation key for a SEE database. Unless 5332 ** activated, none of the SEE routines will work. 5333 */ 5334 SQLITE_API void sqlite3_activate_see( 5335 const char *zPassPhrase /* Activation phrase */ 5336 ); 5337 #endif 5338 5339 #ifdef SQLITE_ENABLE_CEROD 5340 /* 5341 ** Specify the activation key for a CEROD database. Unless 5342 ** activated, none of the CEROD routines will work. 5343 */ 5344 SQLITE_API void sqlite3_activate_cerod( 5345 const char *zPassPhrase /* Activation phrase */ 5346 ); 5347 #endif 5348 5349 /* 5350 ** CAPI3REF: Suspend Execution For A Short Time 5351 ** 5352 ** The sqlite3_sleep() function causes the current thread to suspend execution 5353 ** for at least a number of milliseconds specified in its parameter. 5354 ** 5355 ** If the operating system does not support sleep requests with 5356 ** millisecond time resolution, then the time will be rounded up to 5357 ** the nearest second. The number of milliseconds of sleep actually 5358 ** requested from the operating system is returned. 5359 ** 5360 ** ^SQLite implements this interface by calling the xSleep() 5361 ** method of the default [sqlite3_vfs] object. If the xSleep() method 5362 ** of the default VFS is not implemented correctly, or not implemented at 5363 ** all, then the behavior of sqlite3_sleep() may deviate from the description 5364 ** in the previous paragraphs. 5365 */ 5366 SQLITE_API int sqlite3_sleep(int); 5367 5368 /* 5369 ** CAPI3REF: Name Of The Folder Holding Temporary Files 5370 ** 5371 ** ^(If this global variable is made to point to a string which is 5372 ** the name of a folder (a.k.a. directory), then all temporary files 5373 ** created by SQLite when using a built-in [sqlite3_vfs | VFS] 5374 ** will be placed in that directory.)^ ^If this variable 5375 ** is a NULL pointer, then SQLite performs a search for an appropriate 5376 ** temporary file directory. 5377 ** 5378 ** Applications are strongly discouraged from using this global variable. 5379 ** It is required to set a temporary folder on Windows Runtime (WinRT). 5380 ** But for all other platforms, it is highly recommended that applications 5381 ** neither read nor write this variable. This global variable is a relic 5382 ** that exists for backwards compatibility of legacy applications and should 5383 ** be avoided in new projects. 5384 ** 5385 ** It is not safe to read or modify this variable in more than one 5386 ** thread at a time. It is not safe to read or modify this variable 5387 ** if a [database connection] is being used at the same time in a separate 5388 ** thread. 5389 ** It is intended that this variable be set once 5390 ** as part of process initialization and before any SQLite interface 5391 ** routines have been called and that this variable remain unchanged 5392 ** thereafter. 5393 ** 5394 ** ^The [temp_store_directory pragma] may modify this variable and cause 5395 ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 5396 ** the [temp_store_directory pragma] always assumes that any string 5397 ** that this variable points to is held in memory obtained from 5398 ** [sqlite3_malloc] and the pragma may attempt to free that memory 5399 ** using [sqlite3_free]. 5400 ** Hence, if this variable is modified directly, either it should be 5401 ** made NULL or made to point to memory obtained from [sqlite3_malloc] 5402 ** or else the use of the [temp_store_directory pragma] should be avoided. 5403 ** Except when requested by the [temp_store_directory pragma], SQLite 5404 ** does not free the memory that sqlite3_temp_directory points to. If 5405 ** the application wants that memory to be freed, it must do 5406 ** so itself, taking care to only do so after all [database connection] 5407 ** objects have been destroyed. 5408 ** 5409 ** <b>Note to Windows Runtime users:</b> The temporary directory must be set 5410 ** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 5411 ** features that require the use of temporary files may fail. Here is an 5412 ** example of how to do this using C++ with the Windows Runtime: 5413 ** 5414 ** <blockquote><pre> 5415 ** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 5416 ** TemporaryFolder->Path->Data(); 5417 ** char zPathBuf[MAX_PATH + 1]; 5418 ** memset(zPathBuf, 0, sizeof(zPathBuf)); 5419 ** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 5420 ** NULL, NULL); 5421 ** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 5422 ** </pre></blockquote> 5423 */ 5424 SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory; 5425 5426 /* 5427 ** CAPI3REF: Name Of The Folder Holding Database Files 5428 ** 5429 ** ^(If this global variable is made to point to a string which is 5430 ** the name of a folder (a.k.a. directory), then all database files 5431 ** specified with a relative pathname and created or accessed by 5432 ** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 5433 ** to be relative to that directory.)^ ^If this variable is a NULL 5434 ** pointer, then SQLite assumes that all database files specified 5435 ** with a relative pathname are relative to the current directory 5436 ** for the process. Only the windows VFS makes use of this global 5437 ** variable; it is ignored by the unix VFS. 5438 ** 5439 ** Changing the value of this variable while a database connection is 5440 ** open can result in a corrupt database. 5441 ** 5442 ** It is not safe to read or modify this variable in more than one 5443 ** thread at a time. It is not safe to read or modify this variable 5444 ** if a [database connection] is being used at the same time in a separate 5445 ** thread. 5446 ** It is intended that this variable be set once 5447 ** as part of process initialization and before any SQLite interface 5448 ** routines have been called and that this variable remain unchanged 5449 ** thereafter. 5450 ** 5451 ** ^The [data_store_directory pragma] may modify this variable and cause 5452 ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 5453 ** the [data_store_directory pragma] always assumes that any string 5454 ** that this variable points to is held in memory obtained from 5455 ** [sqlite3_malloc] and the pragma may attempt to free that memory 5456 ** using [sqlite3_free]. 5457 ** Hence, if this variable is modified directly, either it should be 5458 ** made NULL or made to point to memory obtained from [sqlite3_malloc] 5459 ** or else the use of the [data_store_directory pragma] should be avoided. 5460 */ 5461 SQLITE_API SQLITE_EXTERN char *sqlite3_data_directory; 5462 5463 /* 5464 ** CAPI3REF: Test For Auto-Commit Mode 5465 ** KEYWORDS: {autocommit mode} 5466 ** METHOD: sqlite3 5467 ** 5468 ** ^The sqlite3_get_autocommit() interface returns non-zero or 5469 ** zero if the given database connection is or is not in autocommit mode, 5470 ** respectively. ^Autocommit mode is on by default. 5471 ** ^Autocommit mode is disabled by a [BEGIN] statement. 5472 ** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 5473 ** 5474 ** If certain kinds of errors occur on a statement within a multi-statement 5475 ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 5476 ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 5477 ** transaction might be rolled back automatically. The only way to 5478 ** find out whether SQLite automatically rolled back the transaction after 5479 ** an error is to use this function. 5480 ** 5481 ** If another thread changes the autocommit status of the database 5482 ** connection while this routine is running, then the return value 5483 ** is undefined. 5484 */ 5485 SQLITE_API int sqlite3_get_autocommit(sqlite3*); 5486 5487 /* 5488 ** CAPI3REF: Find The Database Handle Of A Prepared Statement 5489 ** METHOD: sqlite3_stmt 5490 ** 5491 ** ^The sqlite3_db_handle interface returns the [database connection] handle 5492 ** to which a [prepared statement] belongs. ^The [database connection] 5493 ** returned by sqlite3_db_handle is the same [database connection] 5494 ** that was the first argument 5495 ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 5496 ** create the statement in the first place. 5497 */ 5498 SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 5499 5500 /* 5501 ** CAPI3REF: Return The Filename For A Database Connection 5502 ** METHOD: sqlite3 5503 ** 5504 ** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename 5505 ** associated with database N of connection D. ^The main database file 5506 ** has the name "main". If there is no attached database N on the database 5507 ** connection D, or if database N is a temporary or in-memory database, then 5508 ** a NULL pointer is returned. 5509 ** 5510 ** ^The filename returned by this function is the output of the 5511 ** xFullPathname method of the [VFS]. ^In other words, the filename 5512 ** will be an absolute pathname, even if the filename used 5513 ** to open the database originally was a URI or relative pathname. 5514 */ 5515 SQLITE_API const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 5516 5517 /* 5518 ** CAPI3REF: Determine if a database is read-only 5519 ** METHOD: sqlite3 5520 ** 5521 ** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 5522 ** of connection D is read-only, 0 if it is read/write, or -1 if N is not 5523 ** the name of a database on connection D. 5524 */ 5525 SQLITE_API int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 5526 5527 /* 5528 ** CAPI3REF: Find the next prepared statement 5529 ** METHOD: sqlite3 5530 ** 5531 ** ^This interface returns a pointer to the next [prepared statement] after 5532 ** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 5533 ** then this interface returns a pointer to the first prepared statement 5534 ** associated with the database connection pDb. ^If no prepared statement 5535 ** satisfies the conditions of this routine, it returns NULL. 5536 ** 5537 ** The [database connection] pointer D in a call to 5538 ** [sqlite3_next_stmt(D,S)] must refer to an open database 5539 ** connection and in particular must not be a NULL pointer. 5540 */ 5541 SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 5542 5543 /* 5544 ** CAPI3REF: Commit And Rollback Notification Callbacks 5545 ** METHOD: sqlite3 5546 ** 5547 ** ^The sqlite3_commit_hook() interface registers a callback 5548 ** function to be invoked whenever a transaction is [COMMIT | committed]. 5549 ** ^Any callback set by a previous call to sqlite3_commit_hook() 5550 ** for the same database connection is overridden. 5551 ** ^The sqlite3_rollback_hook() interface registers a callback 5552 ** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 5553 ** ^Any callback set by a previous call to sqlite3_rollback_hook() 5554 ** for the same database connection is overridden. 5555 ** ^The pArg argument is passed through to the callback. 5556 ** ^If the callback on a commit hook function returns non-zero, 5557 ** then the commit is converted into a rollback. 5558 ** 5559 ** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 5560 ** return the P argument from the previous call of the same function 5561 ** on the same [database connection] D, or NULL for 5562 ** the first call for each function on D. 5563 ** 5564 ** The commit and rollback hook callbacks are not reentrant. 5565 ** The callback implementation must not do anything that will modify 5566 ** the database connection that invoked the callback. Any actions 5567 ** to modify the database connection must be deferred until after the 5568 ** completion of the [sqlite3_step()] call that triggered the commit 5569 ** or rollback hook in the first place. 5570 ** Note that running any other SQL statements, including SELECT statements, 5571 ** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 5572 ** the database connections for the meaning of "modify" in this paragraph. 5573 ** 5574 ** ^Registering a NULL function disables the callback. 5575 ** 5576 ** ^When the commit hook callback routine returns zero, the [COMMIT] 5577 ** operation is allowed to continue normally. ^If the commit hook 5578 ** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 5579 ** ^The rollback hook is invoked on a rollback that results from a commit 5580 ** hook returning non-zero, just as it would be with any other rollback. 5581 ** 5582 ** ^For the purposes of this API, a transaction is said to have been 5583 ** rolled back if an explicit "ROLLBACK" statement is executed, or 5584 ** an error or constraint causes an implicit rollback to occur. 5585 ** ^The rollback callback is not invoked if a transaction is 5586 ** automatically rolled back because the database connection is closed. 5587 ** 5588 ** See also the [sqlite3_update_hook()] interface. 5589 */ 5590 SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 5591 SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 5592 5593 /* 5594 ** CAPI3REF: Data Change Notification Callbacks 5595 ** METHOD: sqlite3 5596 ** 5597 ** ^The sqlite3_update_hook() interface registers a callback function 5598 ** with the [database connection] identified by the first argument 5599 ** to be invoked whenever a row is updated, inserted or deleted in 5600 ** a [rowid table]. 5601 ** ^Any callback set by a previous call to this function 5602 ** for the same database connection is overridden. 5603 ** 5604 ** ^The second argument is a pointer to the function to invoke when a 5605 ** row is updated, inserted or deleted in a rowid table. 5606 ** ^The first argument to the callback is a copy of the third argument 5607 ** to sqlite3_update_hook(). 5608 ** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 5609 ** or [SQLITE_UPDATE], depending on the operation that caused the callback 5610 ** to be invoked. 5611 ** ^The third and fourth arguments to the callback contain pointers to the 5612 ** database and table name containing the affected row. 5613 ** ^The final callback parameter is the [rowid] of the row. 5614 ** ^In the case of an update, this is the [rowid] after the update takes place. 5615 ** 5616 ** ^(The update hook is not invoked when internal system tables are 5617 ** modified (i.e. sqlite_master and sqlite_sequence).)^ 5618 ** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified. 5619 ** 5620 ** ^In the current implementation, the update hook 5621 ** is not invoked when conflicting rows are deleted because of an 5622 ** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 5623 ** invoked when rows are deleted using the [truncate optimization]. 5624 ** The exceptions defined in this paragraph might change in a future 5625 ** release of SQLite. 5626 ** 5627 ** The update hook implementation must not do anything that will modify 5628 ** the database connection that invoked the update hook. Any actions 5629 ** to modify the database connection must be deferred until after the 5630 ** completion of the [sqlite3_step()] call that triggered the update hook. 5631 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 5632 ** database connections for the meaning of "modify" in this paragraph. 5633 ** 5634 ** ^The sqlite3_update_hook(D,C,P) function 5635 ** returns the P argument from the previous call 5636 ** on the same [database connection] D, or NULL for 5637 ** the first call on D. 5638 ** 5639 ** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()], 5640 ** and [sqlite3_preupdate_hook()] interfaces. 5641 */ 5642 SQLITE_API void *sqlite3_update_hook( 5643 sqlite3*, 5644 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 5645 void* 5646 ); 5647 5648 /* 5649 ** CAPI3REF: Enable Or Disable Shared Pager Cache 5650 ** 5651 ** ^(This routine enables or disables the sharing of the database cache 5652 ** and schema data structures between [database connection | connections] 5653 ** to the same database. Sharing is enabled if the argument is true 5654 ** and disabled if the argument is false.)^ 5655 ** 5656 ** ^Cache sharing is enabled and disabled for an entire process. 5657 ** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]). 5658 ** In prior versions of SQLite, 5659 ** sharing was enabled or disabled for each thread separately. 5660 ** 5661 ** ^(The cache sharing mode set by this interface effects all subsequent 5662 ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 5663 ** Existing database connections continue use the sharing mode 5664 ** that was in effect at the time they were opened.)^ 5665 ** 5666 ** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 5667 ** successfully. An [error code] is returned otherwise.)^ 5668 ** 5669 ** ^Shared cache is disabled by default. But this might change in 5670 ** future releases of SQLite. Applications that care about shared 5671 ** cache setting should set it explicitly. 5672 ** 5673 ** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0 5674 ** and will always return SQLITE_MISUSE. On those systems, 5675 ** shared cache mode should be enabled per-database connection via 5676 ** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE]. 5677 ** 5678 ** This interface is threadsafe on processors where writing a 5679 ** 32-bit integer is atomic. 5680 ** 5681 ** See Also: [SQLite Shared-Cache Mode] 5682 */ 5683 SQLITE_API int sqlite3_enable_shared_cache(int); 5684 5685 /* 5686 ** CAPI3REF: Attempt To Free Heap Memory 5687 ** 5688 ** ^The sqlite3_release_memory() interface attempts to free N bytes 5689 ** of heap memory by deallocating non-essential memory allocations 5690 ** held by the database library. Memory used to cache database 5691 ** pages to improve performance is an example of non-essential memory. 5692 ** ^sqlite3_release_memory() returns the number of bytes actually freed, 5693 ** which might be more or less than the amount requested. 5694 ** ^The sqlite3_release_memory() routine is a no-op returning zero 5695 ** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5696 ** 5697 ** See also: [sqlite3_db_release_memory()] 5698 */ 5699 SQLITE_API int sqlite3_release_memory(int); 5700 5701 /* 5702 ** CAPI3REF: Free Memory Used By A Database Connection 5703 ** METHOD: sqlite3 5704 ** 5705 ** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 5706 ** memory as possible from database connection D. Unlike the 5707 ** [sqlite3_release_memory()] interface, this interface is in effect even 5708 ** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 5709 ** omitted. 5710 ** 5711 ** See also: [sqlite3_release_memory()] 5712 */ 5713 SQLITE_API int sqlite3_db_release_memory(sqlite3*); 5714 5715 /* 5716 ** CAPI3REF: Impose A Limit On Heap Size 5717 ** 5718 ** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 5719 ** soft limit on the amount of heap memory that may be allocated by SQLite. 5720 ** ^SQLite strives to keep heap memory utilization below the soft heap 5721 ** limit by reducing the number of pages held in the page cache 5722 ** as heap memory usages approaches the limit. 5723 ** ^The soft heap limit is "soft" because even though SQLite strives to stay 5724 ** below the limit, it will exceed the limit rather than generate 5725 ** an [SQLITE_NOMEM] error. In other words, the soft heap limit 5726 ** is advisory only. 5727 ** 5728 ** ^The return value from sqlite3_soft_heap_limit64() is the size of 5729 ** the soft heap limit prior to the call, or negative in the case of an 5730 ** error. ^If the argument N is negative 5731 ** then no change is made to the soft heap limit. Hence, the current 5732 ** size of the soft heap limit can be determined by invoking 5733 ** sqlite3_soft_heap_limit64() with a negative argument. 5734 ** 5735 ** ^If the argument N is zero then the soft heap limit is disabled. 5736 ** 5737 ** ^(The soft heap limit is not enforced in the current implementation 5738 ** if one or more of following conditions are true: 5739 ** 5740 ** <ul> 5741 ** <li> The soft heap limit is set to zero. 5742 ** <li> Memory accounting is disabled using a combination of the 5743 ** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 5744 ** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 5745 ** <li> An alternative page cache implementation is specified using 5746 ** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 5747 ** <li> The page cache allocates from its own memory pool supplied 5748 ** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 5749 ** from the heap. 5750 ** </ul>)^ 5751 ** 5752 ** Beginning with SQLite [version 3.7.3] ([dateof:3.7.3]), 5753 ** the soft heap limit is enforced 5754 ** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 5755 ** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 5756 ** the soft heap limit is enforced on every memory allocation. Without 5757 ** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 5758 ** when memory is allocated by the page cache. Testing suggests that because 5759 ** the page cache is the predominate memory user in SQLite, most 5760 ** applications will achieve adequate soft heap limit enforcement without 5761 ** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5762 ** 5763 ** The circumstances under which SQLite will enforce the soft heap limit may 5764 ** changes in future releases of SQLite. 5765 */ 5766 SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 5767 5768 /* 5769 ** CAPI3REF: Deprecated Soft Heap Limit Interface 5770 ** DEPRECATED 5771 ** 5772 ** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 5773 ** interface. This routine is provided for historical compatibility 5774 ** only. All new applications should use the 5775 ** [sqlite3_soft_heap_limit64()] interface rather than this one. 5776 */ 5777 SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 5778 5779 5780 /* 5781 ** CAPI3REF: Extract Metadata About A Column Of A Table 5782 ** METHOD: sqlite3 5783 ** 5784 ** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns 5785 ** information about column C of table T in database D 5786 ** on [database connection] X.)^ ^The sqlite3_table_column_metadata() 5787 ** interface returns SQLITE_OK and fills in the non-NULL pointers in 5788 ** the final five arguments with appropriate values if the specified 5789 ** column exists. ^The sqlite3_table_column_metadata() interface returns 5790 ** SQLITE_ERROR and if the specified column does not exist. 5791 ** ^If the column-name parameter to sqlite3_table_column_metadata() is a 5792 ** NULL pointer, then this routine simply checks for the existence of the 5793 ** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it 5794 ** does not. If the table name parameter T in a call to 5795 ** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is 5796 ** undefined behavior. 5797 ** 5798 ** ^The column is identified by the second, third and fourth parameters to 5799 ** this function. ^(The second parameter is either the name of the database 5800 ** (i.e. "main", "temp", or an attached database) containing the specified 5801 ** table or NULL.)^ ^If it is NULL, then all attached databases are searched 5802 ** for the table using the same algorithm used by the database engine to 5803 ** resolve unqualified table references. 5804 ** 5805 ** ^The third and fourth parameters to this function are the table and column 5806 ** name of the desired column, respectively. 5807 ** 5808 ** ^Metadata is returned by writing to the memory locations passed as the 5th 5809 ** and subsequent parameters to this function. ^Any of these arguments may be 5810 ** NULL, in which case the corresponding element of metadata is omitted. 5811 ** 5812 ** ^(<blockquote> 5813 ** <table border="1"> 5814 ** <tr><th> Parameter <th> Output<br>Type <th> Description 5815 ** 5816 ** <tr><td> 5th <td> const char* <td> Data type 5817 ** <tr><td> 6th <td> const char* <td> Name of default collation sequence 5818 ** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 5819 ** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 5820 ** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 5821 ** </table> 5822 ** </blockquote>)^ 5823 ** 5824 ** ^The memory pointed to by the character pointers returned for the 5825 ** declaration type and collation sequence is valid until the next 5826 ** call to any SQLite API function. 5827 ** 5828 ** ^If the specified table is actually a view, an [error code] is returned. 5829 ** 5830 ** ^If the specified column is "rowid", "oid" or "_rowid_" and the table 5831 ** is not a [WITHOUT ROWID] table and an 5832 ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 5833 ** parameters are set for the explicitly declared column. ^(If there is no 5834 ** [INTEGER PRIMARY KEY] column, then the outputs 5835 ** for the [rowid] are set as follows: 5836 ** 5837 ** <pre> 5838 ** data type: "INTEGER" 5839 ** collation sequence: "BINARY" 5840 ** not null: 0 5841 ** primary key: 1 5842 ** auto increment: 0 5843 ** </pre>)^ 5844 ** 5845 ** ^This function causes all database schemas to be read from disk and 5846 ** parsed, if that has not already been done, and returns an error if 5847 ** any errors are encountered while loading the schema. 5848 */ 5849 SQLITE_API int sqlite3_table_column_metadata( 5850 sqlite3 *db, /* Connection handle */ 5851 const char *zDbName, /* Database name or NULL */ 5852 const char *zTableName, /* Table name */ 5853 const char *zColumnName, /* Column name */ 5854 char const **pzDataType, /* OUTPUT: Declared data type */ 5855 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 5856 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 5857 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 5858 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 5859 ); 5860 5861 /* 5862 ** CAPI3REF: Load An Extension 5863 ** METHOD: sqlite3 5864 ** 5865 ** ^This interface loads an SQLite extension library from the named file. 5866 ** 5867 ** ^The sqlite3_load_extension() interface attempts to load an 5868 ** [SQLite extension] library contained in the file zFile. If 5869 ** the file cannot be loaded directly, attempts are made to load 5870 ** with various operating-system specific extensions added. 5871 ** So for example, if "samplelib" cannot be loaded, then names like 5872 ** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might 5873 ** be tried also. 5874 ** 5875 ** ^The entry point is zProc. 5876 ** ^(zProc may be 0, in which case SQLite will try to come up with an 5877 ** entry point name on its own. It first tries "sqlite3_extension_init". 5878 ** If that does not work, it constructs a name "sqlite3_X_init" where the 5879 ** X is consists of the lower-case equivalent of all ASCII alphabetic 5880 ** characters in the filename from the last "/" to the first following 5881 ** "." and omitting any initial "lib".)^ 5882 ** ^The sqlite3_load_extension() interface returns 5883 ** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 5884 ** ^If an error occurs and pzErrMsg is not 0, then the 5885 ** [sqlite3_load_extension()] interface shall attempt to 5886 ** fill *pzErrMsg with error message text stored in memory 5887 ** obtained from [sqlite3_malloc()]. The calling function 5888 ** should free this memory by calling [sqlite3_free()]. 5889 ** 5890 ** ^Extension loading must be enabled using 5891 ** [sqlite3_enable_load_extension()] or 5892 ** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL) 5893 ** prior to calling this API, 5894 ** otherwise an error will be returned. 5895 ** 5896 ** <b>Security warning:</b> It is recommended that the 5897 ** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this 5898 ** interface. The use of the [sqlite3_enable_load_extension()] interface 5899 ** should be avoided. This will keep the SQL function [load_extension()] 5900 ** disabled and prevent SQL injections from giving attackers 5901 ** access to extension loading capabilities. 5902 ** 5903 ** See also the [load_extension() SQL function]. 5904 */ 5905 SQLITE_API int sqlite3_load_extension( 5906 sqlite3 *db, /* Load the extension into this database connection */ 5907 const char *zFile, /* Name of the shared library containing extension */ 5908 const char *zProc, /* Entry point. Derived from zFile if 0 */ 5909 char **pzErrMsg /* Put error message here if not 0 */ 5910 ); 5911 5912 /* 5913 ** CAPI3REF: Enable Or Disable Extension Loading 5914 ** METHOD: sqlite3 5915 ** 5916 ** ^So as not to open security holes in older applications that are 5917 ** unprepared to deal with [extension loading], and as a means of disabling 5918 ** [extension loading] while evaluating user-entered SQL, the following API 5919 ** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 5920 ** 5921 ** ^Extension loading is off by default. 5922 ** ^Call the sqlite3_enable_load_extension() routine with onoff==1 5923 ** to turn extension loading on and call it with onoff==0 to turn 5924 ** it back off again. 5925 ** 5926 ** ^This interface enables or disables both the C-API 5927 ** [sqlite3_load_extension()] and the SQL function [load_extension()]. 5928 ** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..) 5929 ** to enable or disable only the C-API.)^ 5930 ** 5931 ** <b>Security warning:</b> It is recommended that extension loading 5932 ** be disabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method 5933 ** rather than this interface, so the [load_extension()] SQL function 5934 ** remains disabled. This will prevent SQL injections from giving attackers 5935 ** access to extension loading capabilities. 5936 */ 5937 SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 5938 5939 /* 5940 ** CAPI3REF: Automatically Load Statically Linked Extensions 5941 ** 5942 ** ^This interface causes the xEntryPoint() function to be invoked for 5943 ** each new [database connection] that is created. The idea here is that 5944 ** xEntryPoint() is the entry point for a statically linked [SQLite extension] 5945 ** that is to be automatically loaded into all new database connections. 5946 ** 5947 ** ^(Even though the function prototype shows that xEntryPoint() takes 5948 ** no arguments and returns void, SQLite invokes xEntryPoint() with three 5949 ** arguments and expects an integer result as if the signature of the 5950 ** entry point where as follows: 5951 ** 5952 ** <blockquote><pre> 5953 ** int xEntryPoint( 5954 ** sqlite3 *db, 5955 ** const char **pzErrMsg, 5956 ** const struct sqlite3_api_routines *pThunk 5957 ** ); 5958 ** </pre></blockquote>)^ 5959 ** 5960 ** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 5961 ** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 5962 ** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 5963 ** is NULL before calling the xEntryPoint(). ^SQLite will invoke 5964 ** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 5965 ** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 5966 ** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 5967 ** 5968 ** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 5969 ** on the list of automatic extensions is a harmless no-op. ^No entry point 5970 ** will be called more than once for each database connection that is opened. 5971 ** 5972 ** See also: [sqlite3_reset_auto_extension()] 5973 ** and [sqlite3_cancel_auto_extension()] 5974 */ 5975 SQLITE_API int sqlite3_auto_extension(void(*xEntryPoint)(void)); 5976 5977 /* 5978 ** CAPI3REF: Cancel Automatic Extension Loading 5979 ** 5980 ** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the 5981 ** initialization routine X that was registered using a prior call to 5982 ** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)] 5983 ** routine returns 1 if initialization routine X was successfully 5984 ** unregistered and it returns 0 if X was not on the list of initialization 5985 ** routines. 5986 */ 5987 SQLITE_API int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void)); 5988 5989 /* 5990 ** CAPI3REF: Reset Automatic Extension Loading 5991 ** 5992 ** ^This interface disables all automatic extensions previously 5993 ** registered using [sqlite3_auto_extension()]. 5994 */ 5995 SQLITE_API void sqlite3_reset_auto_extension(void); 5996 5997 /* 5998 ** The interface to the virtual-table mechanism is currently considered 5999 ** to be experimental. The interface might change in incompatible ways. 6000 ** If this is a problem for you, do not use the interface at this time. 6001 ** 6002 ** When the virtual-table mechanism stabilizes, we will declare the 6003 ** interface fixed, support it indefinitely, and remove this comment. 6004 */ 6005 6006 /* 6007 ** Structures used by the virtual table interface 6008 */ 6009 typedef struct sqlite3_vtab sqlite3_vtab; 6010 typedef struct sqlite3_index_info sqlite3_index_info; 6011 typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 6012 typedef struct sqlite3_module sqlite3_module; 6013 6014 /* 6015 ** CAPI3REF: Virtual Table Object 6016 ** KEYWORDS: sqlite3_module {virtual table module} 6017 ** 6018 ** This structure, sometimes called a "virtual table module", 6019 ** defines the implementation of a [virtual tables]. 6020 ** This structure consists mostly of methods for the module. 6021 ** 6022 ** ^A virtual table module is created by filling in a persistent 6023 ** instance of this structure and passing a pointer to that instance 6024 ** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 6025 ** ^The registration remains valid until it is replaced by a different 6026 ** module or until the [database connection] closes. The content 6027 ** of this structure must not change while it is registered with 6028 ** any database connection. 6029 */ 6030 struct sqlite3_module { 6031 int iVersion; 6032 int (*xCreate)(sqlite3*, void *pAux, 6033 int argc, const char *const*argv, 6034 sqlite3_vtab **ppVTab, char**); 6035 int (*xConnect)(sqlite3*, void *pAux, 6036 int argc, const char *const*argv, 6037 sqlite3_vtab **ppVTab, char**); 6038 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 6039 int (*xDisconnect)(sqlite3_vtab *pVTab); 6040 int (*xDestroy)(sqlite3_vtab *pVTab); 6041 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 6042 int (*xClose)(sqlite3_vtab_cursor*); 6043 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 6044 int argc, sqlite3_value **argv); 6045 int (*xNext)(sqlite3_vtab_cursor*); 6046 int (*xEof)(sqlite3_vtab_cursor*); 6047 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 6048 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 6049 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 6050 int (*xBegin)(sqlite3_vtab *pVTab); 6051 int (*xSync)(sqlite3_vtab *pVTab); 6052 int (*xCommit)(sqlite3_vtab *pVTab); 6053 int (*xRollback)(sqlite3_vtab *pVTab); 6054 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 6055 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 6056 void **ppArg); 6057 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 6058 /* The methods above are in version 1 of the sqlite_module object. Those 6059 ** below are for version 2 and greater. */ 6060 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 6061 int (*xRelease)(sqlite3_vtab *pVTab, int); 6062 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 6063 }; 6064 6065 /* 6066 ** CAPI3REF: Virtual Table Indexing Information 6067 ** KEYWORDS: sqlite3_index_info 6068 ** 6069 ** The sqlite3_index_info structure and its substructures is used as part 6070 ** of the [virtual table] interface to 6071 ** pass information into and receive the reply from the [xBestIndex] 6072 ** method of a [virtual table module]. The fields under **Inputs** are the 6073 ** inputs to xBestIndex and are read-only. xBestIndex inserts its 6074 ** results into the **Outputs** fields. 6075 ** 6076 ** ^(The aConstraint[] array records WHERE clause constraints of the form: 6077 ** 6078 ** <blockquote>column OP expr</blockquote> 6079 ** 6080 ** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 6081 ** stored in aConstraint[].op using one of the 6082 ** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 6083 ** ^(The index of the column is stored in 6084 ** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 6085 ** expr on the right-hand side can be evaluated (and thus the constraint 6086 ** is usable) and false if it cannot.)^ 6087 ** 6088 ** ^The optimizer automatically inverts terms of the form "expr OP column" 6089 ** and makes other simplifications to the WHERE clause in an attempt to 6090 ** get as many WHERE clause terms into the form shown above as possible. 6091 ** ^The aConstraint[] array only reports WHERE clause terms that are 6092 ** relevant to the particular virtual table being queried. 6093 ** 6094 ** ^Information about the ORDER BY clause is stored in aOrderBy[]. 6095 ** ^Each term of aOrderBy records a column of the ORDER BY clause. 6096 ** 6097 ** The colUsed field indicates which columns of the virtual table may be 6098 ** required by the current scan. Virtual table columns are numbered from 6099 ** zero in the order in which they appear within the CREATE TABLE statement 6100 ** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62), 6101 ** the corresponding bit is set within the colUsed mask if the column may be 6102 ** required by SQLite. If the table has at least 64 columns and any column 6103 ** to the right of the first 63 is required, then bit 63 of colUsed is also 6104 ** set. In other words, column iCol may be required if the expression 6105 ** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to 6106 ** non-zero. 6107 ** 6108 ** The [xBestIndex] method must fill aConstraintUsage[] with information 6109 ** about what parameters to pass to xFilter. ^If argvIndex>0 then 6110 ** the right-hand side of the corresponding aConstraint[] is evaluated 6111 ** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 6112 ** is true, then the constraint is assumed to be fully handled by the 6113 ** virtual table and is not checked again by SQLite.)^ 6114 ** 6115 ** ^The idxNum and idxPtr values are recorded and passed into the 6116 ** [xFilter] method. 6117 ** ^[sqlite3_free()] is used to free idxPtr if and only if 6118 ** needToFreeIdxPtr is true. 6119 ** 6120 ** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 6121 ** the correct order to satisfy the ORDER BY clause so that no separate 6122 ** sorting step is required. 6123 ** 6124 ** ^The estimatedCost value is an estimate of the cost of a particular 6125 ** strategy. A cost of N indicates that the cost of the strategy is similar 6126 ** to a linear scan of an SQLite table with N rows. A cost of log(N) 6127 ** indicates that the expense of the operation is similar to that of a 6128 ** binary search on a unique indexed field of an SQLite table with N rows. 6129 ** 6130 ** ^The estimatedRows value is an estimate of the number of rows that 6131 ** will be returned by the strategy. 6132 ** 6133 ** The xBestIndex method may optionally populate the idxFlags field with a 6134 ** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag - 6135 ** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite 6136 ** assumes that the strategy may visit at most one row. 6137 ** 6138 ** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then 6139 ** SQLite also assumes that if a call to the xUpdate() method is made as 6140 ** part of the same statement to delete or update a virtual table row and the 6141 ** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback 6142 ** any database changes. In other words, if the xUpdate() returns 6143 ** SQLITE_CONSTRAINT, the database contents must be exactly as they were 6144 ** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not 6145 ** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by 6146 ** the xUpdate method are automatically rolled back by SQLite. 6147 ** 6148 ** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info 6149 ** structure for SQLite [version 3.8.2] ([dateof:3.8.2]). 6150 ** If a virtual table extension is 6151 ** used with an SQLite version earlier than 3.8.2, the results of attempting 6152 ** to read or write the estimatedRows field are undefined (but are likely 6153 ** to included crashing the application). The estimatedRows field should 6154 ** therefore only be used if [sqlite3_libversion_number()] returns a 6155 ** value greater than or equal to 3008002. Similarly, the idxFlags field 6156 ** was added for [version 3.9.0] ([dateof:3.9.0]). 6157 ** It may therefore only be used if 6158 ** sqlite3_libversion_number() returns a value greater than or equal to 6159 ** 3009000. 6160 */ 6161 struct sqlite3_index_info { 6162 /* Inputs */ 6163 int nConstraint; /* Number of entries in aConstraint */ 6164 struct sqlite3_index_constraint { 6165 int iColumn; /* Column constrained. -1 for ROWID */ 6166 unsigned char op; /* Constraint operator */ 6167 unsigned char usable; /* True if this constraint is usable */ 6168 int iTermOffset; /* Used internally - xBestIndex should ignore */ 6169 } *aConstraint; /* Table of WHERE clause constraints */ 6170 int nOrderBy; /* Number of terms in the ORDER BY clause */ 6171 struct sqlite3_index_orderby { 6172 int iColumn; /* Column number */ 6173 unsigned char desc; /* True for DESC. False for ASC. */ 6174 } *aOrderBy; /* The ORDER BY clause */ 6175 /* Outputs */ 6176 struct sqlite3_index_constraint_usage { 6177 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 6178 unsigned char omit; /* Do not code a test for this constraint */ 6179 } *aConstraintUsage; 6180 int idxNum; /* Number used to identify the index */ 6181 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 6182 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 6183 int orderByConsumed; /* True if output is already ordered */ 6184 double estimatedCost; /* Estimated cost of using this index */ 6185 /* Fields below are only available in SQLite 3.8.2 and later */ 6186 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */ 6187 /* Fields below are only available in SQLite 3.9.0 and later */ 6188 int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */ 6189 /* Fields below are only available in SQLite 3.10.0 and later */ 6190 sqlite3_uint64 colUsed; /* Input: Mask of columns used by statement */ 6191 }; 6192 6193 /* 6194 ** CAPI3REF: Virtual Table Scan Flags 6195 */ 6196 #define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */ 6197 6198 /* 6199 ** CAPI3REF: Virtual Table Constraint Operator Codes 6200 ** 6201 ** These macros defined the allowed values for the 6202 ** [sqlite3_index_info].aConstraint[].op field. Each value represents 6203 ** an operator that is part of a constraint term in the wHERE clause of 6204 ** a query that uses a [virtual table]. 6205 */ 6206 #define SQLITE_INDEX_CONSTRAINT_EQ 2 6207 #define SQLITE_INDEX_CONSTRAINT_GT 4 6208 #define SQLITE_INDEX_CONSTRAINT_LE 8 6209 #define SQLITE_INDEX_CONSTRAINT_LT 16 6210 #define SQLITE_INDEX_CONSTRAINT_GE 32 6211 #define SQLITE_INDEX_CONSTRAINT_MATCH 64 6212 #define SQLITE_INDEX_CONSTRAINT_LIKE 65 6213 #define SQLITE_INDEX_CONSTRAINT_GLOB 66 6214 #define SQLITE_INDEX_CONSTRAINT_REGEXP 67 6215 6216 /* 6217 ** CAPI3REF: Register A Virtual Table Implementation 6218 ** METHOD: sqlite3 6219 ** 6220 ** ^These routines are used to register a new [virtual table module] name. 6221 ** ^Module names must be registered before 6222 ** creating a new [virtual table] using the module and before using a 6223 ** preexisting [virtual table] for the module. 6224 ** 6225 ** ^The module name is registered on the [database connection] specified 6226 ** by the first parameter. ^The name of the module is given by the 6227 ** second parameter. ^The third parameter is a pointer to 6228 ** the implementation of the [virtual table module]. ^The fourth 6229 ** parameter is an arbitrary client data pointer that is passed through 6230 ** into the [xCreate] and [xConnect] methods of the virtual table module 6231 ** when a new virtual table is be being created or reinitialized. 6232 ** 6233 ** ^The sqlite3_create_module_v2() interface has a fifth parameter which 6234 ** is a pointer to a destructor for the pClientData. ^SQLite will 6235 ** invoke the destructor function (if it is not NULL) when SQLite 6236 ** no longer needs the pClientData pointer. ^The destructor will also 6237 ** be invoked if the call to sqlite3_create_module_v2() fails. 6238 ** ^The sqlite3_create_module() 6239 ** interface is equivalent to sqlite3_create_module_v2() with a NULL 6240 ** destructor. 6241 */ 6242 SQLITE_API int sqlite3_create_module( 6243 sqlite3 *db, /* SQLite connection to register module with */ 6244 const char *zName, /* Name of the module */ 6245 const sqlite3_module *p, /* Methods for the module */ 6246 void *pClientData /* Client data for xCreate/xConnect */ 6247 ); 6248 SQLITE_API int sqlite3_create_module_v2( 6249 sqlite3 *db, /* SQLite connection to register module with */ 6250 const char *zName, /* Name of the module */ 6251 const sqlite3_module *p, /* Methods for the module */ 6252 void *pClientData, /* Client data for xCreate/xConnect */ 6253 void(*xDestroy)(void*) /* Module destructor function */ 6254 ); 6255 6256 /* 6257 ** CAPI3REF: Virtual Table Instance Object 6258 ** KEYWORDS: sqlite3_vtab 6259 ** 6260 ** Every [virtual table module] implementation uses a subclass 6261 ** of this object to describe a particular instance 6262 ** of the [virtual table]. Each subclass will 6263 ** be tailored to the specific needs of the module implementation. 6264 ** The purpose of this superclass is to define certain fields that are 6265 ** common to all module implementations. 6266 ** 6267 ** ^Virtual tables methods can set an error message by assigning a 6268 ** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 6269 ** take care that any prior string is freed by a call to [sqlite3_free()] 6270 ** prior to assigning a new string to zErrMsg. ^After the error message 6271 ** is delivered up to the client application, the string will be automatically 6272 ** freed by sqlite3_free() and the zErrMsg field will be zeroed. 6273 */ 6274 struct sqlite3_vtab { 6275 const sqlite3_module *pModule; /* The module for this virtual table */ 6276 int nRef; /* Number of open cursors */ 6277 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 6278 /* Virtual table implementations will typically add additional fields */ 6279 }; 6280 6281 /* 6282 ** CAPI3REF: Virtual Table Cursor Object 6283 ** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 6284 ** 6285 ** Every [virtual table module] implementation uses a subclass of the 6286 ** following structure to describe cursors that point into the 6287 ** [virtual table] and are used 6288 ** to loop through the virtual table. Cursors are created using the 6289 ** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 6290 ** by the [sqlite3_module.xClose | xClose] method. Cursors are used 6291 ** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 6292 ** of the module. Each module implementation will define 6293 ** the content of a cursor structure to suit its own needs. 6294 ** 6295 ** This superclass exists in order to define fields of the cursor that 6296 ** are common to all implementations. 6297 */ 6298 struct sqlite3_vtab_cursor { 6299 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 6300 /* Virtual table implementations will typically add additional fields */ 6301 }; 6302 6303 /* 6304 ** CAPI3REF: Declare The Schema Of A Virtual Table 6305 ** 6306 ** ^The [xCreate] and [xConnect] methods of a 6307 ** [virtual table module] call this interface 6308 ** to declare the format (the names and datatypes of the columns) of 6309 ** the virtual tables they implement. 6310 */ 6311 SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 6312 6313 /* 6314 ** CAPI3REF: Overload A Function For A Virtual Table 6315 ** METHOD: sqlite3 6316 ** 6317 ** ^(Virtual tables can provide alternative implementations of functions 6318 ** using the [xFindFunction] method of the [virtual table module]. 6319 ** But global versions of those functions 6320 ** must exist in order to be overloaded.)^ 6321 ** 6322 ** ^(This API makes sure a global version of a function with a particular 6323 ** name and number of parameters exists. If no such function exists 6324 ** before this API is called, a new function is created.)^ ^The implementation 6325 ** of the new function always causes an exception to be thrown. So 6326 ** the new function is not good for anything by itself. Its only 6327 ** purpose is to be a placeholder function that can be overloaded 6328 ** by a [virtual table]. 6329 */ 6330 SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 6331 6332 /* 6333 ** The interface to the virtual-table mechanism defined above (back up 6334 ** to a comment remarkably similar to this one) is currently considered 6335 ** to be experimental. The interface might change in incompatible ways. 6336 ** If this is a problem for you, do not use the interface at this time. 6337 ** 6338 ** When the virtual-table mechanism stabilizes, we will declare the 6339 ** interface fixed, support it indefinitely, and remove this comment. 6340 */ 6341 6342 /* 6343 ** CAPI3REF: A Handle To An Open BLOB 6344 ** KEYWORDS: {BLOB handle} {BLOB handles} 6345 ** 6346 ** An instance of this object represents an open BLOB on which 6347 ** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 6348 ** ^Objects of this type are created by [sqlite3_blob_open()] 6349 ** and destroyed by [sqlite3_blob_close()]. 6350 ** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 6351 ** can be used to read or write small subsections of the BLOB. 6352 ** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 6353 */ 6354 typedef struct sqlite3_blob sqlite3_blob; 6355 6356 /* 6357 ** CAPI3REF: Open A BLOB For Incremental I/O 6358 ** METHOD: sqlite3 6359 ** CONSTRUCTOR: sqlite3_blob 6360 ** 6361 ** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 6362 ** in row iRow, column zColumn, table zTable in database zDb; 6363 ** in other words, the same BLOB that would be selected by: 6364 ** 6365 ** <pre> 6366 ** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 6367 ** </pre>)^ 6368 ** 6369 ** ^(Parameter zDb is not the filename that contains the database, but 6370 ** rather the symbolic name of the database. For attached databases, this is 6371 ** the name that appears after the AS keyword in the [ATTACH] statement. 6372 ** For the main database file, the database name is "main". For TEMP 6373 ** tables, the database name is "temp".)^ 6374 ** 6375 ** ^If the flags parameter is non-zero, then the BLOB is opened for read 6376 ** and write access. ^If the flags parameter is zero, the BLOB is opened for 6377 ** read-only access. 6378 ** 6379 ** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored 6380 ** in *ppBlob. Otherwise an [error code] is returned and, unless the error 6381 ** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided 6382 ** the API is not misused, it is always safe to call [sqlite3_blob_close()] 6383 ** on *ppBlob after this function it returns. 6384 ** 6385 ** This function fails with SQLITE_ERROR if any of the following are true: 6386 ** <ul> 6387 ** <li> ^(Database zDb does not exist)^, 6388 ** <li> ^(Table zTable does not exist within database zDb)^, 6389 ** <li> ^(Table zTable is a WITHOUT ROWID table)^, 6390 ** <li> ^(Column zColumn does not exist)^, 6391 ** <li> ^(Row iRow is not present in the table)^, 6392 ** <li> ^(The specified column of row iRow contains a value that is not 6393 ** a TEXT or BLOB value)^, 6394 ** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE 6395 ** constraint and the blob is being opened for read/write access)^, 6396 ** <li> ^([foreign key constraints | Foreign key constraints] are enabled, 6397 ** column zColumn is part of a [child key] definition and the blob is 6398 ** being opened for read/write access)^. 6399 ** </ul> 6400 ** 6401 ** ^Unless it returns SQLITE_MISUSE, this function sets the 6402 ** [database connection] error code and message accessible via 6403 ** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 6404 ** 6405 ** A BLOB referenced by sqlite3_blob_open() may be read using the 6406 ** [sqlite3_blob_read()] interface and modified by using 6407 ** [sqlite3_blob_write()]. The [BLOB handle] can be moved to a 6408 ** different row of the same table using the [sqlite3_blob_reopen()] 6409 ** interface. However, the column, table, or database of a [BLOB handle] 6410 ** cannot be changed after the [BLOB handle] is opened. 6411 ** 6412 ** ^(If the row that a BLOB handle points to is modified by an 6413 ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 6414 ** then the BLOB handle is marked as "expired". 6415 ** This is true if any column of the row is changed, even a column 6416 ** other than the one the BLOB handle is open on.)^ 6417 ** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 6418 ** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 6419 ** ^(Changes written into a BLOB prior to the BLOB expiring are not 6420 ** rolled back by the expiration of the BLOB. Such changes will eventually 6421 ** commit if the transaction continues to completion.)^ 6422 ** 6423 ** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 6424 ** the opened blob. ^The size of a blob may not be changed by this 6425 ** interface. Use the [UPDATE] SQL command to change the size of a 6426 ** blob. 6427 ** 6428 ** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 6429 ** and the built-in [zeroblob] SQL function may be used to create a 6430 ** zero-filled blob to read or write using the incremental-blob interface. 6431 ** 6432 ** To avoid a resource leak, every open [BLOB handle] should eventually 6433 ** be released by a call to [sqlite3_blob_close()]. 6434 ** 6435 ** See also: [sqlite3_blob_close()], 6436 ** [sqlite3_blob_reopen()], [sqlite3_blob_read()], 6437 ** [sqlite3_blob_bytes()], [sqlite3_blob_write()]. 6438 */ 6439 SQLITE_API int sqlite3_blob_open( 6440 sqlite3*, 6441 const char *zDb, 6442 const char *zTable, 6443 const char *zColumn, 6444 sqlite3_int64 iRow, 6445 int flags, 6446 sqlite3_blob **ppBlob 6447 ); 6448 6449 /* 6450 ** CAPI3REF: Move a BLOB Handle to a New Row 6451 ** METHOD: sqlite3_blob 6452 ** 6453 ** ^This function is used to move an existing [BLOB handle] so that it points 6454 ** to a different row of the same database table. ^The new row is identified 6455 ** by the rowid value passed as the second argument. Only the row can be 6456 ** changed. ^The database, table and column on which the blob handle is open 6457 ** remain the same. Moving an existing [BLOB handle] to a new row is 6458 ** faster than closing the existing handle and opening a new one. 6459 ** 6460 ** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 6461 ** it must exist and there must be either a blob or text value stored in 6462 ** the nominated column.)^ ^If the new row is not present in the table, or if 6463 ** it does not contain a blob or text value, or if another error occurs, an 6464 ** SQLite error code is returned and the blob handle is considered aborted. 6465 ** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 6466 ** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 6467 ** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 6468 ** always returns zero. 6469 ** 6470 ** ^This function sets the database handle error code and message. 6471 */ 6472 SQLITE_API int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 6473 6474 /* 6475 ** CAPI3REF: Close A BLOB Handle 6476 ** DESTRUCTOR: sqlite3_blob 6477 ** 6478 ** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed 6479 ** unconditionally. Even if this routine returns an error code, the 6480 ** handle is still closed.)^ 6481 ** 6482 ** ^If the blob handle being closed was opened for read-write access, and if 6483 ** the database is in auto-commit mode and there are no other open read-write 6484 ** blob handles or active write statements, the current transaction is 6485 ** committed. ^If an error occurs while committing the transaction, an error 6486 ** code is returned and the transaction rolled back. 6487 ** 6488 ** Calling this function with an argument that is not a NULL pointer or an 6489 ** open blob handle results in undefined behaviour. ^Calling this routine 6490 ** with a null pointer (such as would be returned by a failed call to 6491 ** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function 6492 ** is passed a valid open blob handle, the values returned by the 6493 ** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning. 6494 */ 6495 SQLITE_API int sqlite3_blob_close(sqlite3_blob *); 6496 6497 /* 6498 ** CAPI3REF: Return The Size Of An Open BLOB 6499 ** METHOD: sqlite3_blob 6500 ** 6501 ** ^Returns the size in bytes of the BLOB accessible via the 6502 ** successfully opened [BLOB handle] in its only argument. ^The 6503 ** incremental blob I/O routines can only read or overwriting existing 6504 ** blob content; they cannot change the size of a blob. 6505 ** 6506 ** This routine only works on a [BLOB handle] which has been created 6507 ** by a prior successful call to [sqlite3_blob_open()] and which has not 6508 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6509 ** to this routine results in undefined and probably undesirable behavior. 6510 */ 6511 SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *); 6512 6513 /* 6514 ** CAPI3REF: Read Data From A BLOB Incrementally 6515 ** METHOD: sqlite3_blob 6516 ** 6517 ** ^(This function is used to read data from an open [BLOB handle] into a 6518 ** caller-supplied buffer. N bytes of data are copied into buffer Z 6519 ** from the open BLOB, starting at offset iOffset.)^ 6520 ** 6521 ** ^If offset iOffset is less than N bytes from the end of the BLOB, 6522 ** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 6523 ** less than zero, [SQLITE_ERROR] is returned and no data is read. 6524 ** ^The size of the blob (and hence the maximum value of N+iOffset) 6525 ** can be determined using the [sqlite3_blob_bytes()] interface. 6526 ** 6527 ** ^An attempt to read from an expired [BLOB handle] fails with an 6528 ** error code of [SQLITE_ABORT]. 6529 ** 6530 ** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 6531 ** Otherwise, an [error code] or an [extended error code] is returned.)^ 6532 ** 6533 ** This routine only works on a [BLOB handle] which has been created 6534 ** by a prior successful call to [sqlite3_blob_open()] and which has not 6535 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6536 ** to this routine results in undefined and probably undesirable behavior. 6537 ** 6538 ** See also: [sqlite3_blob_write()]. 6539 */ 6540 SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 6541 6542 /* 6543 ** CAPI3REF: Write Data Into A BLOB Incrementally 6544 ** METHOD: sqlite3_blob 6545 ** 6546 ** ^(This function is used to write data into an open [BLOB handle] from a 6547 ** caller-supplied buffer. N bytes of data are copied from the buffer Z 6548 ** into the open BLOB, starting at offset iOffset.)^ 6549 ** 6550 ** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 6551 ** Otherwise, an [error code] or an [extended error code] is returned.)^ 6552 ** ^Unless SQLITE_MISUSE is returned, this function sets the 6553 ** [database connection] error code and message accessible via 6554 ** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 6555 ** 6556 ** ^If the [BLOB handle] passed as the first argument was not opened for 6557 ** writing (the flags parameter to [sqlite3_blob_open()] was zero), 6558 ** this function returns [SQLITE_READONLY]. 6559 ** 6560 ** This function may only modify the contents of the BLOB; it is 6561 ** not possible to increase the size of a BLOB using this API. 6562 ** ^If offset iOffset is less than N bytes from the end of the BLOB, 6563 ** [SQLITE_ERROR] is returned and no data is written. The size of the 6564 ** BLOB (and hence the maximum value of N+iOffset) can be determined 6565 ** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less 6566 ** than zero [SQLITE_ERROR] is returned and no data is written. 6567 ** 6568 ** ^An attempt to write to an expired [BLOB handle] fails with an 6569 ** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 6570 ** before the [BLOB handle] expired are not rolled back by the 6571 ** expiration of the handle, though of course those changes might 6572 ** have been overwritten by the statement that expired the BLOB handle 6573 ** or by other independent statements. 6574 ** 6575 ** This routine only works on a [BLOB handle] which has been created 6576 ** by a prior successful call to [sqlite3_blob_open()] and which has not 6577 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6578 ** to this routine results in undefined and probably undesirable behavior. 6579 ** 6580 ** See also: [sqlite3_blob_read()]. 6581 */ 6582 SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 6583 6584 /* 6585 ** CAPI3REF: Virtual File System Objects 6586 ** 6587 ** A virtual filesystem (VFS) is an [sqlite3_vfs] object 6588 ** that SQLite uses to interact 6589 ** with the underlying operating system. Most SQLite builds come with a 6590 ** single default VFS that is appropriate for the host computer. 6591 ** New VFSes can be registered and existing VFSes can be unregistered. 6592 ** The following interfaces are provided. 6593 ** 6594 ** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 6595 ** ^Names are case sensitive. 6596 ** ^Names are zero-terminated UTF-8 strings. 6597 ** ^If there is no match, a NULL pointer is returned. 6598 ** ^If zVfsName is NULL then the default VFS is returned. 6599 ** 6600 ** ^New VFSes are registered with sqlite3_vfs_register(). 6601 ** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 6602 ** ^The same VFS can be registered multiple times without injury. 6603 ** ^To make an existing VFS into the default VFS, register it again 6604 ** with the makeDflt flag set. If two different VFSes with the 6605 ** same name are registered, the behavior is undefined. If a 6606 ** VFS is registered with a name that is NULL or an empty string, 6607 ** then the behavior is undefined. 6608 ** 6609 ** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 6610 ** ^(If the default VFS is unregistered, another VFS is chosen as 6611 ** the default. The choice for the new VFS is arbitrary.)^ 6612 */ 6613 SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 6614 SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 6615 SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*); 6616 6617 /* 6618 ** CAPI3REF: Mutexes 6619 ** 6620 ** The SQLite core uses these routines for thread 6621 ** synchronization. Though they are intended for internal 6622 ** use by SQLite, code that links against SQLite is 6623 ** permitted to use any of these routines. 6624 ** 6625 ** The SQLite source code contains multiple implementations 6626 ** of these mutex routines. An appropriate implementation 6627 ** is selected automatically at compile-time. The following 6628 ** implementations are available in the SQLite core: 6629 ** 6630 ** <ul> 6631 ** <li> SQLITE_MUTEX_PTHREADS 6632 ** <li> SQLITE_MUTEX_W32 6633 ** <li> SQLITE_MUTEX_NOOP 6634 ** </ul> 6635 ** 6636 ** The SQLITE_MUTEX_NOOP implementation is a set of routines 6637 ** that does no real locking and is appropriate for use in 6638 ** a single-threaded application. The SQLITE_MUTEX_PTHREADS and 6639 ** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 6640 ** and Windows. 6641 ** 6642 ** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 6643 ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 6644 ** implementation is included with the library. In this case the 6645 ** application must supply a custom mutex implementation using the 6646 ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 6647 ** before calling sqlite3_initialize() or any other public sqlite3_ 6648 ** function that calls sqlite3_initialize(). 6649 ** 6650 ** ^The sqlite3_mutex_alloc() routine allocates a new 6651 ** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc() 6652 ** routine returns NULL if it is unable to allocate the requested 6653 ** mutex. The argument to sqlite3_mutex_alloc() must one of these 6654 ** integer constants: 6655 ** 6656 ** <ul> 6657 ** <li> SQLITE_MUTEX_FAST 6658 ** <li> SQLITE_MUTEX_RECURSIVE 6659 ** <li> SQLITE_MUTEX_STATIC_MASTER 6660 ** <li> SQLITE_MUTEX_STATIC_MEM 6661 ** <li> SQLITE_MUTEX_STATIC_OPEN 6662 ** <li> SQLITE_MUTEX_STATIC_PRNG 6663 ** <li> SQLITE_MUTEX_STATIC_LRU 6664 ** <li> SQLITE_MUTEX_STATIC_PMEM 6665 ** <li> SQLITE_MUTEX_STATIC_APP1 6666 ** <li> SQLITE_MUTEX_STATIC_APP2 6667 ** <li> SQLITE_MUTEX_STATIC_APP3 6668 ** <li> SQLITE_MUTEX_STATIC_VFS1 6669 ** <li> SQLITE_MUTEX_STATIC_VFS2 6670 ** <li> SQLITE_MUTEX_STATIC_VFS3 6671 ** </ul> 6672 ** 6673 ** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 6674 ** cause sqlite3_mutex_alloc() to create 6675 ** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 6676 ** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 6677 ** The mutex implementation does not need to make a distinction 6678 ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 6679 ** not want to. SQLite will only request a recursive mutex in 6680 ** cases where it really needs one. If a faster non-recursive mutex 6681 ** implementation is available on the host platform, the mutex subsystem 6682 ** might return such a mutex in response to SQLITE_MUTEX_FAST. 6683 ** 6684 ** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 6685 ** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 6686 ** a pointer to a static preexisting mutex. ^Nine static mutexes are 6687 ** used by the current version of SQLite. Future versions of SQLite 6688 ** may add additional static mutexes. Static mutexes are for internal 6689 ** use by SQLite only. Applications that use SQLite mutexes should 6690 ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 6691 ** SQLITE_MUTEX_RECURSIVE. 6692 ** 6693 ** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 6694 ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 6695 ** returns a different mutex on every call. ^For the static 6696 ** mutex types, the same mutex is returned on every call that has 6697 ** the same type number. 6698 ** 6699 ** ^The sqlite3_mutex_free() routine deallocates a previously 6700 ** allocated dynamic mutex. Attempting to deallocate a static 6701 ** mutex results in undefined behavior. 6702 ** 6703 ** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 6704 ** to enter a mutex. ^If another thread is already within the mutex, 6705 ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 6706 ** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 6707 ** upon successful entry. ^(Mutexes created using 6708 ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 6709 ** In such cases, the 6710 ** mutex must be exited an equal number of times before another thread 6711 ** can enter.)^ If the same thread tries to enter any mutex other 6712 ** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined. 6713 ** 6714 ** ^(Some systems (for example, Windows 95) do not support the operation 6715 ** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 6716 ** will always return SQLITE_BUSY. The SQLite core only ever uses 6717 ** sqlite3_mutex_try() as an optimization so this is acceptable 6718 ** behavior.)^ 6719 ** 6720 ** ^The sqlite3_mutex_leave() routine exits a mutex that was 6721 ** previously entered by the same thread. The behavior 6722 ** is undefined if the mutex is not currently entered by the 6723 ** calling thread or is not currently allocated. 6724 ** 6725 ** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 6726 ** sqlite3_mutex_leave() is a NULL pointer, then all three routines 6727 ** behave as no-ops. 6728 ** 6729 ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 6730 */ 6731 SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int); 6732 SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*); 6733 SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*); 6734 SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*); 6735 SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*); 6736 6737 /* 6738 ** CAPI3REF: Mutex Methods Object 6739 ** 6740 ** An instance of this structure defines the low-level routines 6741 ** used to allocate and use mutexes. 6742 ** 6743 ** Usually, the default mutex implementations provided by SQLite are 6744 ** sufficient, however the application has the option of substituting a custom 6745 ** implementation for specialized deployments or systems for which SQLite 6746 ** does not provide a suitable implementation. In this case, the application 6747 ** creates and populates an instance of this structure to pass 6748 ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 6749 ** Additionally, an instance of this structure can be used as an 6750 ** output variable when querying the system for the current mutex 6751 ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 6752 ** 6753 ** ^The xMutexInit method defined by this structure is invoked as 6754 ** part of system initialization by the sqlite3_initialize() function. 6755 ** ^The xMutexInit routine is called by SQLite exactly once for each 6756 ** effective call to [sqlite3_initialize()]. 6757 ** 6758 ** ^The xMutexEnd method defined by this structure is invoked as 6759 ** part of system shutdown by the sqlite3_shutdown() function. The 6760 ** implementation of this method is expected to release all outstanding 6761 ** resources obtained by the mutex methods implementation, especially 6762 ** those obtained by the xMutexInit method. ^The xMutexEnd() 6763 ** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 6764 ** 6765 ** ^(The remaining seven methods defined by this structure (xMutexAlloc, 6766 ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 6767 ** xMutexNotheld) implement the following interfaces (respectively): 6768 ** 6769 ** <ul> 6770 ** <li> [sqlite3_mutex_alloc()] </li> 6771 ** <li> [sqlite3_mutex_free()] </li> 6772 ** <li> [sqlite3_mutex_enter()] </li> 6773 ** <li> [sqlite3_mutex_try()] </li> 6774 ** <li> [sqlite3_mutex_leave()] </li> 6775 ** <li> [sqlite3_mutex_held()] </li> 6776 ** <li> [sqlite3_mutex_notheld()] </li> 6777 ** </ul>)^ 6778 ** 6779 ** The only difference is that the public sqlite3_XXX functions enumerated 6780 ** above silently ignore any invocations that pass a NULL pointer instead 6781 ** of a valid mutex handle. The implementations of the methods defined 6782 ** by this structure are not required to handle this case, the results 6783 ** of passing a NULL pointer instead of a valid mutex handle are undefined 6784 ** (i.e. it is acceptable to provide an implementation that segfaults if 6785 ** it is passed a NULL pointer). 6786 ** 6787 ** The xMutexInit() method must be threadsafe. It must be harmless to 6788 ** invoke xMutexInit() multiple times within the same process and without 6789 ** intervening calls to xMutexEnd(). Second and subsequent calls to 6790 ** xMutexInit() must be no-ops. 6791 ** 6792 ** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 6793 ** and its associates). Similarly, xMutexAlloc() must not use SQLite memory 6794 ** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 6795 ** memory allocation for a fast or recursive mutex. 6796 ** 6797 ** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 6798 ** called, but only if the prior call to xMutexInit returned SQLITE_OK. 6799 ** If xMutexInit fails in any way, it is expected to clean up after itself 6800 ** prior to returning. 6801 */ 6802 typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 6803 struct sqlite3_mutex_methods { 6804 int (*xMutexInit)(void); 6805 int (*xMutexEnd)(void); 6806 sqlite3_mutex *(*xMutexAlloc)(int); 6807 void (*xMutexFree)(sqlite3_mutex *); 6808 void (*xMutexEnter)(sqlite3_mutex *); 6809 int (*xMutexTry)(sqlite3_mutex *); 6810 void (*xMutexLeave)(sqlite3_mutex *); 6811 int (*xMutexHeld)(sqlite3_mutex *); 6812 int (*xMutexNotheld)(sqlite3_mutex *); 6813 }; 6814 6815 /* 6816 ** CAPI3REF: Mutex Verification Routines 6817 ** 6818 ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 6819 ** are intended for use inside assert() statements. The SQLite core 6820 ** never uses these routines except inside an assert() and applications 6821 ** are advised to follow the lead of the core. The SQLite core only 6822 ** provides implementations for these routines when it is compiled 6823 ** with the SQLITE_DEBUG flag. External mutex implementations 6824 ** are only required to provide these routines if SQLITE_DEBUG is 6825 ** defined and if NDEBUG is not defined. 6826 ** 6827 ** These routines should return true if the mutex in their argument 6828 ** is held or not held, respectively, by the calling thread. 6829 ** 6830 ** The implementation is not required to provide versions of these 6831 ** routines that actually work. If the implementation does not provide working 6832 ** versions of these routines, it should at least provide stubs that always 6833 ** return true so that one does not get spurious assertion failures. 6834 ** 6835 ** If the argument to sqlite3_mutex_held() is a NULL pointer then 6836 ** the routine should return 1. This seems counter-intuitive since 6837 ** clearly the mutex cannot be held if it does not exist. But 6838 ** the reason the mutex does not exist is because the build is not 6839 ** using mutexes. And we do not want the assert() containing the 6840 ** call to sqlite3_mutex_held() to fail, so a non-zero return is 6841 ** the appropriate thing to do. The sqlite3_mutex_notheld() 6842 ** interface should also return 1 when given a NULL pointer. 6843 */ 6844 #ifndef NDEBUG 6845 SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*); 6846 SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*); 6847 #endif 6848 6849 /* 6850 ** CAPI3REF: Mutex Types 6851 ** 6852 ** The [sqlite3_mutex_alloc()] interface takes a single argument 6853 ** which is one of these integer constants. 6854 ** 6855 ** The set of static mutexes may change from one SQLite release to the 6856 ** next. Applications that override the built-in mutex logic must be 6857 ** prepared to accommodate additional static mutexes. 6858 */ 6859 #define SQLITE_MUTEX_FAST 0 6860 #define SQLITE_MUTEX_RECURSIVE 1 6861 #define SQLITE_MUTEX_STATIC_MASTER 2 6862 #define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 6863 #define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 6864 #define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 6865 #define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_randomness() */ 6866 #define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 6867 #define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 6868 #define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 6869 #define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */ 6870 #define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */ 6871 #define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */ 6872 #define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */ 6873 #define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */ 6874 #define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */ 6875 6876 /* 6877 ** CAPI3REF: Retrieve the mutex for a database connection 6878 ** METHOD: sqlite3 6879 ** 6880 ** ^This interface returns a pointer the [sqlite3_mutex] object that 6881 ** serializes access to the [database connection] given in the argument 6882 ** when the [threading mode] is Serialized. 6883 ** ^If the [threading mode] is Single-thread or Multi-thread then this 6884 ** routine returns a NULL pointer. 6885 */ 6886 SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 6887 6888 /* 6889 ** CAPI3REF: Low-Level Control Of Database Files 6890 ** METHOD: sqlite3 6891 ** 6892 ** ^The [sqlite3_file_control()] interface makes a direct call to the 6893 ** xFileControl method for the [sqlite3_io_methods] object associated 6894 ** with a particular database identified by the second argument. ^The 6895 ** name of the database is "main" for the main database or "temp" for the 6896 ** TEMP database, or the name that appears after the AS keyword for 6897 ** databases that are added using the [ATTACH] SQL command. 6898 ** ^A NULL pointer can be used in place of "main" to refer to the 6899 ** main database file. 6900 ** ^The third and fourth parameters to this routine 6901 ** are passed directly through to the second and third parameters of 6902 ** the xFileControl method. ^The return value of the xFileControl 6903 ** method becomes the return value of this routine. 6904 ** 6905 ** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes 6906 ** a pointer to the underlying [sqlite3_file] object to be written into 6907 ** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER 6908 ** case is a short-circuit path which does not actually invoke the 6909 ** underlying sqlite3_io_methods.xFileControl method. 6910 ** 6911 ** ^If the second parameter (zDbName) does not match the name of any 6912 ** open database file, then SQLITE_ERROR is returned. ^This error 6913 ** code is not remembered and will not be recalled by [sqlite3_errcode()] 6914 ** or [sqlite3_errmsg()]. The underlying xFileControl method might 6915 ** also return SQLITE_ERROR. There is no way to distinguish between 6916 ** an incorrect zDbName and an SQLITE_ERROR return from the underlying 6917 ** xFileControl method. 6918 ** 6919 ** See also: [SQLITE_FCNTL_LOCKSTATE] 6920 */ 6921 SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 6922 6923 /* 6924 ** CAPI3REF: Testing Interface 6925 ** 6926 ** ^The sqlite3_test_control() interface is used to read out internal 6927 ** state of SQLite and to inject faults into SQLite for testing 6928 ** purposes. ^The first parameter is an operation code that determines 6929 ** the number, meaning, and operation of all subsequent parameters. 6930 ** 6931 ** This interface is not for use by applications. It exists solely 6932 ** for verifying the correct operation of the SQLite library. Depending 6933 ** on how the SQLite library is compiled, this interface might not exist. 6934 ** 6935 ** The details of the operation codes, their meanings, the parameters 6936 ** they take, and what they do are all subject to change without notice. 6937 ** Unlike most of the SQLite API, this function is not guaranteed to 6938 ** operate consistently from one release to the next. 6939 */ 6940 SQLITE_API int sqlite3_test_control(int op, ...); 6941 6942 /* 6943 ** CAPI3REF: Testing Interface Operation Codes 6944 ** 6945 ** These constants are the valid operation code parameters used 6946 ** as the first argument to [sqlite3_test_control()]. 6947 ** 6948 ** These parameters and their meanings are subject to change 6949 ** without notice. These values are for testing purposes only. 6950 ** Applications should not use any of these parameters or the 6951 ** [sqlite3_test_control()] interface. 6952 */ 6953 #define SQLITE_TESTCTRL_FIRST 5 6954 #define SQLITE_TESTCTRL_PRNG_SAVE 5 6955 #define SQLITE_TESTCTRL_PRNG_RESTORE 6 6956 #define SQLITE_TESTCTRL_PRNG_RESET 7 6957 #define SQLITE_TESTCTRL_BITVEC_TEST 8 6958 #define SQLITE_TESTCTRL_FAULT_INSTALL 9 6959 #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 6960 #define SQLITE_TESTCTRL_PENDING_BYTE 11 6961 #define SQLITE_TESTCTRL_ASSERT 12 6962 #define SQLITE_TESTCTRL_ALWAYS 13 6963 #define SQLITE_TESTCTRL_RESERVE 14 6964 #define SQLITE_TESTCTRL_OPTIMIZATIONS 15 6965 #define SQLITE_TESTCTRL_ISKEYWORD 16 6966 #define SQLITE_TESTCTRL_SCRATCHMALLOC 17 6967 #define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 6968 #define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */ 6969 #define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD 19 6970 #define SQLITE_TESTCTRL_NEVER_CORRUPT 20 6971 #define SQLITE_TESTCTRL_VDBE_COVERAGE 21 6972 #define SQLITE_TESTCTRL_BYTEORDER 22 6973 #define SQLITE_TESTCTRL_ISINIT 23 6974 #define SQLITE_TESTCTRL_SORTER_MMAP 24 6975 #define SQLITE_TESTCTRL_IMPOSTER 25 6976 #define SQLITE_TESTCTRL_LAST 25 6977 6978 /* 6979 ** CAPI3REF: SQLite Runtime Status 6980 ** 6981 ** ^These interfaces are used to retrieve runtime status information 6982 ** about the performance of SQLite, and optionally to reset various 6983 ** highwater marks. ^The first argument is an integer code for 6984 ** the specific parameter to measure. ^(Recognized integer codes 6985 ** are of the form [status parameters | SQLITE_STATUS_...].)^ 6986 ** ^The current value of the parameter is returned into *pCurrent. 6987 ** ^The highest recorded value is returned in *pHighwater. ^If the 6988 ** resetFlag is true, then the highest record value is reset after 6989 ** *pHighwater is written. ^(Some parameters do not record the highest 6990 ** value. For those parameters 6991 ** nothing is written into *pHighwater and the resetFlag is ignored.)^ 6992 ** ^(Other parameters record only the highwater mark and not the current 6993 ** value. For these latter parameters nothing is written into *pCurrent.)^ 6994 ** 6995 ** ^The sqlite3_status() and sqlite3_status64() routines return 6996 ** SQLITE_OK on success and a non-zero [error code] on failure. 6997 ** 6998 ** If either the current value or the highwater mark is too large to 6999 ** be represented by a 32-bit integer, then the values returned by 7000 ** sqlite3_status() are undefined. 7001 ** 7002 ** See also: [sqlite3_db_status()] 7003 */ 7004 SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 7005 SQLITE_API int sqlite3_status64( 7006 int op, 7007 sqlite3_int64 *pCurrent, 7008 sqlite3_int64 *pHighwater, 7009 int resetFlag 7010 ); 7011 7012 7013 /* 7014 ** CAPI3REF: Status Parameters 7015 ** KEYWORDS: {status parameters} 7016 ** 7017 ** These integer constants designate various run-time status parameters 7018 ** that can be returned by [sqlite3_status()]. 7019 ** 7020 ** <dl> 7021 ** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 7022 ** <dd>This parameter is the current amount of memory checked out 7023 ** using [sqlite3_malloc()], either directly or indirectly. The 7024 ** figure includes calls made to [sqlite3_malloc()] by the application 7025 ** and internal memory usage by the SQLite library. Scratch memory 7026 ** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 7027 ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 7028 ** this parameter. The amount returned is the sum of the allocation 7029 ** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 7030 ** 7031 ** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 7032 ** <dd>This parameter records the largest memory allocation request 7033 ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 7034 ** internal equivalents). Only the value returned in the 7035 ** *pHighwater parameter to [sqlite3_status()] is of interest. 7036 ** The value written into the *pCurrent parameter is undefined.</dd>)^ 7037 ** 7038 ** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 7039 ** <dd>This parameter records the number of separate memory allocations 7040 ** currently checked out.</dd>)^ 7041 ** 7042 ** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 7043 ** <dd>This parameter returns the number of pages used out of the 7044 ** [pagecache memory allocator] that was configured using 7045 ** [SQLITE_CONFIG_PAGECACHE]. The 7046 ** value returned is in pages, not in bytes.</dd>)^ 7047 ** 7048 ** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 7049 ** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 7050 ** <dd>This parameter returns the number of bytes of page cache 7051 ** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 7052 ** buffer and where forced to overflow to [sqlite3_malloc()]. The 7053 ** returned value includes allocations that overflowed because they 7054 ** where too large (they were larger than the "sz" parameter to 7055 ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 7056 ** no space was left in the page cache.</dd>)^ 7057 ** 7058 ** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 7059 ** <dd>This parameter records the largest memory allocation request 7060 ** handed to [pagecache memory allocator]. Only the value returned in the 7061 ** *pHighwater parameter to [sqlite3_status()] is of interest. 7062 ** The value written into the *pCurrent parameter is undefined.</dd>)^ 7063 ** 7064 ** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt> 7065 ** <dd>This parameter returns the number of allocations used out of the 7066 ** [scratch memory allocator] configured using 7067 ** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 7068 ** in bytes. Since a single thread may only have one scratch allocation 7069 ** outstanding at time, this parameter also reports the number of threads 7070 ** using scratch memory at the same time.</dd>)^ 7071 ** 7072 ** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 7073 ** <dd>This parameter returns the number of bytes of scratch memory 7074 ** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH] 7075 ** buffer and where forced to overflow to [sqlite3_malloc()]. The values 7076 ** returned include overflows because the requested allocation was too 7077 ** larger (that is, because the requested allocation was larger than the 7078 ** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 7079 ** slots were available. 7080 ** </dd>)^ 7081 ** 7082 ** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 7083 ** <dd>This parameter records the largest memory allocation request 7084 ** handed to [scratch memory allocator]. Only the value returned in the 7085 ** *pHighwater parameter to [sqlite3_status()] is of interest. 7086 ** The value written into the *pCurrent parameter is undefined.</dd>)^ 7087 ** 7088 ** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 7089 ** <dd>The *pHighwater parameter records the deepest parser stack. 7090 ** The *pCurrent value is undefined. The *pHighwater value is only 7091 ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 7092 ** </dl> 7093 ** 7094 ** New status parameters may be added from time to time. 7095 */ 7096 #define SQLITE_STATUS_MEMORY_USED 0 7097 #define SQLITE_STATUS_PAGECACHE_USED 1 7098 #define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 7099 #define SQLITE_STATUS_SCRATCH_USED 3 7100 #define SQLITE_STATUS_SCRATCH_OVERFLOW 4 7101 #define SQLITE_STATUS_MALLOC_SIZE 5 7102 #define SQLITE_STATUS_PARSER_STACK 6 7103 #define SQLITE_STATUS_PAGECACHE_SIZE 7 7104 #define SQLITE_STATUS_SCRATCH_SIZE 8 7105 #define SQLITE_STATUS_MALLOC_COUNT 9 7106 7107 /* 7108 ** CAPI3REF: Database Connection Status 7109 ** METHOD: sqlite3 7110 ** 7111 ** ^This interface is used to retrieve runtime status information 7112 ** about a single [database connection]. ^The first argument is the 7113 ** database connection object to be interrogated. ^The second argument 7114 ** is an integer constant, taken from the set of 7115 ** [SQLITE_DBSTATUS options], that 7116 ** determines the parameter to interrogate. The set of 7117 ** [SQLITE_DBSTATUS options] is likely 7118 ** to grow in future releases of SQLite. 7119 ** 7120 ** ^The current value of the requested parameter is written into *pCur 7121 ** and the highest instantaneous value is written into *pHiwtr. ^If 7122 ** the resetFlg is true, then the highest instantaneous value is 7123 ** reset back down to the current value. 7124 ** 7125 ** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 7126 ** non-zero [error code] on failure. 7127 ** 7128 ** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 7129 */ 7130 SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 7131 7132 /* 7133 ** CAPI3REF: Status Parameters for database connections 7134 ** KEYWORDS: {SQLITE_DBSTATUS options} 7135 ** 7136 ** These constants are the available integer "verbs" that can be passed as 7137 ** the second argument to the [sqlite3_db_status()] interface. 7138 ** 7139 ** New verbs may be added in future releases of SQLite. Existing verbs 7140 ** might be discontinued. Applications should check the return code from 7141 ** [sqlite3_db_status()] to make sure that the call worked. 7142 ** The [sqlite3_db_status()] interface will return a non-zero error code 7143 ** if a discontinued or unsupported verb is invoked. 7144 ** 7145 ** <dl> 7146 ** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 7147 ** <dd>This parameter returns the number of lookaside memory slots currently 7148 ** checked out.</dd>)^ 7149 ** 7150 ** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 7151 ** <dd>This parameter returns the number malloc attempts that were 7152 ** satisfied using lookaside memory. Only the high-water value is meaningful; 7153 ** the current value is always zero.)^ 7154 ** 7155 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 7156 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 7157 ** <dd>This parameter returns the number malloc attempts that might have 7158 ** been satisfied using lookaside memory but failed due to the amount of 7159 ** memory requested being larger than the lookaside slot size. 7160 ** Only the high-water value is meaningful; 7161 ** the current value is always zero.)^ 7162 ** 7163 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 7164 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 7165 ** <dd>This parameter returns the number malloc attempts that might have 7166 ** been satisfied using lookaside memory but failed due to all lookaside 7167 ** memory already being in use. 7168 ** Only the high-water value is meaningful; 7169 ** the current value is always zero.)^ 7170 ** 7171 ** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 7172 ** <dd>This parameter returns the approximate number of bytes of heap 7173 ** memory used by all pager caches associated with the database connection.)^ 7174 ** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 7175 ** 7176 ** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]] 7177 ** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt> 7178 ** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a 7179 ** pager cache is shared between two or more connections the bytes of heap 7180 ** memory used by that pager cache is divided evenly between the attached 7181 ** connections.)^ In other words, if none of the pager caches associated 7182 ** with the database connection are shared, this request returns the same 7183 ** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are 7184 ** shared, the value returned by this call will be smaller than that returned 7185 ** by DBSTATUS_CACHE_USED. ^The highwater mark associated with 7186 ** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0. 7187 ** 7188 ** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 7189 ** <dd>This parameter returns the approximate number of bytes of heap 7190 ** memory used to store the schema for all databases associated 7191 ** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 7192 ** ^The full amount of memory used by the schemas is reported, even if the 7193 ** schema memory is shared with other database connections due to 7194 ** [shared cache mode] being enabled. 7195 ** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 7196 ** 7197 ** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 7198 ** <dd>This parameter returns the approximate number of bytes of heap 7199 ** and lookaside memory used by all prepared statements associated with 7200 ** the database connection.)^ 7201 ** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 7202 ** </dd> 7203 ** 7204 ** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 7205 ** <dd>This parameter returns the number of pager cache hits that have 7206 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 7207 ** is always 0. 7208 ** </dd> 7209 ** 7210 ** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 7211 ** <dd>This parameter returns the number of pager cache misses that have 7212 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 7213 ** is always 0. 7214 ** </dd> 7215 ** 7216 ** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 7217 ** <dd>This parameter returns the number of dirty cache entries that have 7218 ** been written to disk. Specifically, the number of pages written to the 7219 ** wal file in wal mode databases, or the number of pages written to the 7220 ** database file in rollback mode databases. Any pages written as part of 7221 ** transaction rollback or database recovery operations are not included. 7222 ** If an IO or other error occurs while writing a page to disk, the effect 7223 ** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 7224 ** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 7225 ** </dd> 7226 ** 7227 ** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt> 7228 ** <dd>This parameter returns zero for the current value if and only if 7229 ** all foreign key constraints (deferred or immediate) have been 7230 ** resolved.)^ ^The highwater mark is always 0. 7231 ** </dd> 7232 ** </dl> 7233 */ 7234 #define SQLITE_DBSTATUS_LOOKASIDE_USED 0 7235 #define SQLITE_DBSTATUS_CACHE_USED 1 7236 #define SQLITE_DBSTATUS_SCHEMA_USED 2 7237 #define SQLITE_DBSTATUS_STMT_USED 3 7238 #define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 7239 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 7240 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 7241 #define SQLITE_DBSTATUS_CACHE_HIT 7 7242 #define SQLITE_DBSTATUS_CACHE_MISS 8 7243 #define SQLITE_DBSTATUS_CACHE_WRITE 9 7244 #define SQLITE_DBSTATUS_DEFERRED_FKS 10 7245 #define SQLITE_DBSTATUS_CACHE_USED_SHARED 11 7246 #define SQLITE_DBSTATUS_MAX 11 /* Largest defined DBSTATUS */ 7247 7248 7249 /* 7250 ** CAPI3REF: Prepared Statement Status 7251 ** METHOD: sqlite3_stmt 7252 ** 7253 ** ^(Each prepared statement maintains various 7254 ** [SQLITE_STMTSTATUS counters] that measure the number 7255 ** of times it has performed specific operations.)^ These counters can 7256 ** be used to monitor the performance characteristics of the prepared 7257 ** statements. For example, if the number of table steps greatly exceeds 7258 ** the number of table searches or result rows, that would tend to indicate 7259 ** that the prepared statement is using a full table scan rather than 7260 ** an index. 7261 ** 7262 ** ^(This interface is used to retrieve and reset counter values from 7263 ** a [prepared statement]. The first argument is the prepared statement 7264 ** object to be interrogated. The second argument 7265 ** is an integer code for a specific [SQLITE_STMTSTATUS counter] 7266 ** to be interrogated.)^ 7267 ** ^The current value of the requested counter is returned. 7268 ** ^If the resetFlg is true, then the counter is reset to zero after this 7269 ** interface call returns. 7270 ** 7271 ** See also: [sqlite3_status()] and [sqlite3_db_status()]. 7272 */ 7273 SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 7274 7275 /* 7276 ** CAPI3REF: Status Parameters for prepared statements 7277 ** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 7278 ** 7279 ** These preprocessor macros define integer codes that name counter 7280 ** values associated with the [sqlite3_stmt_status()] interface. 7281 ** The meanings of the various counters are as follows: 7282 ** 7283 ** <dl> 7284 ** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 7285 ** <dd>^This is the number of times that SQLite has stepped forward in 7286 ** a table as part of a full table scan. Large numbers for this counter 7287 ** may indicate opportunities for performance improvement through 7288 ** careful use of indices.</dd> 7289 ** 7290 ** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 7291 ** <dd>^This is the number of sort operations that have occurred. 7292 ** A non-zero value in this counter may indicate an opportunity to 7293 ** improvement performance through careful use of indices.</dd> 7294 ** 7295 ** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 7296 ** <dd>^This is the number of rows inserted into transient indices that 7297 ** were created automatically in order to help joins run faster. 7298 ** A non-zero value in this counter may indicate an opportunity to 7299 ** improvement performance by adding permanent indices that do not 7300 ** need to be reinitialized each time the statement is run.</dd> 7301 ** 7302 ** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt> 7303 ** <dd>^This is the number of virtual machine operations executed 7304 ** by the prepared statement if that number is less than or equal 7305 ** to 2147483647. The number of virtual machine operations can be 7306 ** used as a proxy for the total work done by the prepared statement. 7307 ** If the number of virtual machine operations exceeds 2147483647 7308 ** then the value returned by this statement status code is undefined. 7309 ** 7310 ** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt> 7311 ** <dd>^This is the number of times that the prepare statement has been 7312 ** automatically regenerated due to schema changes or change to 7313 ** [bound parameters] that might affect the query plan. 7314 ** 7315 ** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt> 7316 ** <dd>^This is the number of times that the prepared statement has 7317 ** been run. A single "run" for the purposes of this counter is one 7318 ** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()]. 7319 ** The counter is incremented on the first [sqlite3_step()] call of each 7320 ** cycle. 7321 ** 7322 ** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt> 7323 ** <dd>^This is the approximate number of bytes of heap memory 7324 ** used to store the prepared statement. ^This value is not actually 7325 ** a counter, and so the resetFlg parameter to sqlite3_stmt_status() 7326 ** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED. 7327 ** </dd> 7328 ** </dl> 7329 */ 7330 #define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 7331 #define SQLITE_STMTSTATUS_SORT 2 7332 #define SQLITE_STMTSTATUS_AUTOINDEX 3 7333 #define SQLITE_STMTSTATUS_VM_STEP 4 7334 #define SQLITE_STMTSTATUS_REPREPARE 5 7335 #define SQLITE_STMTSTATUS_RUN 6 7336 #define SQLITE_STMTSTATUS_MEMUSED 99 7337 7338 /* 7339 ** CAPI3REF: Custom Page Cache Object 7340 ** 7341 ** The sqlite3_pcache type is opaque. It is implemented by 7342 ** the pluggable module. The SQLite core has no knowledge of 7343 ** its size or internal structure and never deals with the 7344 ** sqlite3_pcache object except by holding and passing pointers 7345 ** to the object. 7346 ** 7347 ** See [sqlite3_pcache_methods2] for additional information. 7348 */ 7349 typedef struct sqlite3_pcache sqlite3_pcache; 7350 7351 /* 7352 ** CAPI3REF: Custom Page Cache Object 7353 ** 7354 ** The sqlite3_pcache_page object represents a single page in the 7355 ** page cache. The page cache will allocate instances of this 7356 ** object. Various methods of the page cache use pointers to instances 7357 ** of this object as parameters or as their return value. 7358 ** 7359 ** See [sqlite3_pcache_methods2] for additional information. 7360 */ 7361 typedef struct sqlite3_pcache_page sqlite3_pcache_page; 7362 struct sqlite3_pcache_page { 7363 void *pBuf; /* The content of the page */ 7364 void *pExtra; /* Extra information associated with the page */ 7365 }; 7366 7367 /* 7368 ** CAPI3REF: Application Defined Page Cache. 7369 ** KEYWORDS: {page cache} 7370 ** 7371 ** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 7372 ** register an alternative page cache implementation by passing in an 7373 ** instance of the sqlite3_pcache_methods2 structure.)^ 7374 ** In many applications, most of the heap memory allocated by 7375 ** SQLite is used for the page cache. 7376 ** By implementing a 7377 ** custom page cache using this API, an application can better control 7378 ** the amount of memory consumed by SQLite, the way in which 7379 ** that memory is allocated and released, and the policies used to 7380 ** determine exactly which parts of a database file are cached and for 7381 ** how long. 7382 ** 7383 ** The alternative page cache mechanism is an 7384 ** extreme measure that is only needed by the most demanding applications. 7385 ** The built-in page cache is recommended for most uses. 7386 ** 7387 ** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 7388 ** internal buffer by SQLite within the call to [sqlite3_config]. Hence 7389 ** the application may discard the parameter after the call to 7390 ** [sqlite3_config()] returns.)^ 7391 ** 7392 ** [[the xInit() page cache method]] 7393 ** ^(The xInit() method is called once for each effective 7394 ** call to [sqlite3_initialize()])^ 7395 ** (usually only once during the lifetime of the process). ^(The xInit() 7396 ** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 7397 ** The intent of the xInit() method is to set up global data structures 7398 ** required by the custom page cache implementation. 7399 ** ^(If the xInit() method is NULL, then the 7400 ** built-in default page cache is used instead of the application defined 7401 ** page cache.)^ 7402 ** 7403 ** [[the xShutdown() page cache method]] 7404 ** ^The xShutdown() method is called by [sqlite3_shutdown()]. 7405 ** It can be used to clean up 7406 ** any outstanding resources before process shutdown, if required. 7407 ** ^The xShutdown() method may be NULL. 7408 ** 7409 ** ^SQLite automatically serializes calls to the xInit method, 7410 ** so the xInit method need not be threadsafe. ^The 7411 ** xShutdown method is only called from [sqlite3_shutdown()] so it does 7412 ** not need to be threadsafe either. All other methods must be threadsafe 7413 ** in multithreaded applications. 7414 ** 7415 ** ^SQLite will never invoke xInit() more than once without an intervening 7416 ** call to xShutdown(). 7417 ** 7418 ** [[the xCreate() page cache methods]] 7419 ** ^SQLite invokes the xCreate() method to construct a new cache instance. 7420 ** SQLite will typically create one cache instance for each open database file, 7421 ** though this is not guaranteed. ^The 7422 ** first parameter, szPage, is the size in bytes of the pages that must 7423 ** be allocated by the cache. ^szPage will always a power of two. ^The 7424 ** second parameter szExtra is a number of bytes of extra storage 7425 ** associated with each page cache entry. ^The szExtra parameter will 7426 ** a number less than 250. SQLite will use the 7427 ** extra szExtra bytes on each page to store metadata about the underlying 7428 ** database page on disk. The value passed into szExtra depends 7429 ** on the SQLite version, the target platform, and how SQLite was compiled. 7430 ** ^The third argument to xCreate(), bPurgeable, is true if the cache being 7431 ** created will be used to cache database pages of a file stored on disk, or 7432 ** false if it is used for an in-memory database. The cache implementation 7433 ** does not have to do anything special based with the value of bPurgeable; 7434 ** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 7435 ** never invoke xUnpin() except to deliberately delete a page. 7436 ** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 7437 ** false will always have the "discard" flag set to true. 7438 ** ^Hence, a cache created with bPurgeable false will 7439 ** never contain any unpinned pages. 7440 ** 7441 ** [[the xCachesize() page cache method]] 7442 ** ^(The xCachesize() method may be called at any time by SQLite to set the 7443 ** suggested maximum cache-size (number of pages stored by) the cache 7444 ** instance passed as the first argument. This is the value configured using 7445 ** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 7446 ** parameter, the implementation is not required to do anything with this 7447 ** value; it is advisory only. 7448 ** 7449 ** [[the xPagecount() page cache methods]] 7450 ** The xPagecount() method must return the number of pages currently 7451 ** stored in the cache, both pinned and unpinned. 7452 ** 7453 ** [[the xFetch() page cache methods]] 7454 ** The xFetch() method locates a page in the cache and returns a pointer to 7455 ** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 7456 ** The pBuf element of the returned sqlite3_pcache_page object will be a 7457 ** pointer to a buffer of szPage bytes used to store the content of a 7458 ** single database page. The pExtra element of sqlite3_pcache_page will be 7459 ** a pointer to the szExtra bytes of extra storage that SQLite has requested 7460 ** for each entry in the page cache. 7461 ** 7462 ** The page to be fetched is determined by the key. ^The minimum key value 7463 ** is 1. After it has been retrieved using xFetch, the page is considered 7464 ** to be "pinned". 7465 ** 7466 ** If the requested page is already in the page cache, then the page cache 7467 ** implementation must return a pointer to the page buffer with its content 7468 ** intact. If the requested page is not already in the cache, then the 7469 ** cache implementation should use the value of the createFlag 7470 ** parameter to help it determined what action to take: 7471 ** 7472 ** <table border=1 width=85% align=center> 7473 ** <tr><th> createFlag <th> Behavior when page is not already in cache 7474 ** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 7475 ** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 7476 ** Otherwise return NULL. 7477 ** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 7478 ** NULL if allocating a new page is effectively impossible. 7479 ** </table> 7480 ** 7481 ** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 7482 ** will only use a createFlag of 2 after a prior call with a createFlag of 1 7483 ** failed.)^ In between the to xFetch() calls, SQLite may 7484 ** attempt to unpin one or more cache pages by spilling the content of 7485 ** pinned pages to disk and synching the operating system disk cache. 7486 ** 7487 ** [[the xUnpin() page cache method]] 7488 ** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 7489 ** as its second argument. If the third parameter, discard, is non-zero, 7490 ** then the page must be evicted from the cache. 7491 ** ^If the discard parameter is 7492 ** zero, then the page may be discarded or retained at the discretion of 7493 ** page cache implementation. ^The page cache implementation 7494 ** may choose to evict unpinned pages at any time. 7495 ** 7496 ** The cache must not perform any reference counting. A single 7497 ** call to xUnpin() unpins the page regardless of the number of prior calls 7498 ** to xFetch(). 7499 ** 7500 ** [[the xRekey() page cache methods]] 7501 ** The xRekey() method is used to change the key value associated with the 7502 ** page passed as the second argument. If the cache 7503 ** previously contains an entry associated with newKey, it must be 7504 ** discarded. ^Any prior cache entry associated with newKey is guaranteed not 7505 ** to be pinned. 7506 ** 7507 ** When SQLite calls the xTruncate() method, the cache must discard all 7508 ** existing cache entries with page numbers (keys) greater than or equal 7509 ** to the value of the iLimit parameter passed to xTruncate(). If any 7510 ** of these pages are pinned, they are implicitly unpinned, meaning that 7511 ** they can be safely discarded. 7512 ** 7513 ** [[the xDestroy() page cache method]] 7514 ** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 7515 ** All resources associated with the specified cache should be freed. ^After 7516 ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 7517 ** handle invalid, and will not use it with any other sqlite3_pcache_methods2 7518 ** functions. 7519 ** 7520 ** [[the xShrink() page cache method]] 7521 ** ^SQLite invokes the xShrink() method when it wants the page cache to 7522 ** free up as much of heap memory as possible. The page cache implementation 7523 ** is not obligated to free any memory, but well-behaved implementations should 7524 ** do their best. 7525 */ 7526 typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 7527 struct sqlite3_pcache_methods2 { 7528 int iVersion; 7529 void *pArg; 7530 int (*xInit)(void*); 7531 void (*xShutdown)(void*); 7532 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 7533 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 7534 int (*xPagecount)(sqlite3_pcache*); 7535 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 7536 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 7537 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 7538 unsigned oldKey, unsigned newKey); 7539 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 7540 void (*xDestroy)(sqlite3_pcache*); 7541 void (*xShrink)(sqlite3_pcache*); 7542 }; 7543 7544 /* 7545 ** This is the obsolete pcache_methods object that has now been replaced 7546 ** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 7547 ** retained in the header file for backwards compatibility only. 7548 */ 7549 typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 7550 struct sqlite3_pcache_methods { 7551 void *pArg; 7552 int (*xInit)(void*); 7553 void (*xShutdown)(void*); 7554 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 7555 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 7556 int (*xPagecount)(sqlite3_pcache*); 7557 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 7558 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 7559 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 7560 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 7561 void (*xDestroy)(sqlite3_pcache*); 7562 }; 7563 7564 7565 /* 7566 ** CAPI3REF: Online Backup Object 7567 ** 7568 ** The sqlite3_backup object records state information about an ongoing 7569 ** online backup operation. ^The sqlite3_backup object is created by 7570 ** a call to [sqlite3_backup_init()] and is destroyed by a call to 7571 ** [sqlite3_backup_finish()]. 7572 ** 7573 ** See Also: [Using the SQLite Online Backup API] 7574 */ 7575 typedef struct sqlite3_backup sqlite3_backup; 7576 7577 /* 7578 ** CAPI3REF: Online Backup API. 7579 ** 7580 ** The backup API copies the content of one database into another. 7581 ** It is useful either for creating backups of databases or 7582 ** for copying in-memory databases to or from persistent files. 7583 ** 7584 ** See Also: [Using the SQLite Online Backup API] 7585 ** 7586 ** ^SQLite holds a write transaction open on the destination database file 7587 ** for the duration of the backup operation. 7588 ** ^The source database is read-locked only while it is being read; 7589 ** it is not locked continuously for the entire backup operation. 7590 ** ^Thus, the backup may be performed on a live source database without 7591 ** preventing other database connections from 7592 ** reading or writing to the source database while the backup is underway. 7593 ** 7594 ** ^(To perform a backup operation: 7595 ** <ol> 7596 ** <li><b>sqlite3_backup_init()</b> is called once to initialize the 7597 ** backup, 7598 ** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 7599 ** the data between the two databases, and finally 7600 ** <li><b>sqlite3_backup_finish()</b> is called to release all resources 7601 ** associated with the backup operation. 7602 ** </ol>)^ 7603 ** There should be exactly one call to sqlite3_backup_finish() for each 7604 ** successful call to sqlite3_backup_init(). 7605 ** 7606 ** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 7607 ** 7608 ** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 7609 ** [database connection] associated with the destination database 7610 ** and the database name, respectively. 7611 ** ^The database name is "main" for the main database, "temp" for the 7612 ** temporary database, or the name specified after the AS keyword in 7613 ** an [ATTACH] statement for an attached database. 7614 ** ^The S and M arguments passed to 7615 ** sqlite3_backup_init(D,N,S,M) identify the [database connection] 7616 ** and database name of the source database, respectively. 7617 ** ^The source and destination [database connections] (parameters S and D) 7618 ** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 7619 ** an error. 7620 ** 7621 ** ^A call to sqlite3_backup_init() will fail, returning NULL, if 7622 ** there is already a read or read-write transaction open on the 7623 ** destination database. 7624 ** 7625 ** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 7626 ** returned and an error code and error message are stored in the 7627 ** destination [database connection] D. 7628 ** ^The error code and message for the failed call to sqlite3_backup_init() 7629 ** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 7630 ** [sqlite3_errmsg16()] functions. 7631 ** ^A successful call to sqlite3_backup_init() returns a pointer to an 7632 ** [sqlite3_backup] object. 7633 ** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 7634 ** sqlite3_backup_finish() functions to perform the specified backup 7635 ** operation. 7636 ** 7637 ** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 7638 ** 7639 ** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 7640 ** the source and destination databases specified by [sqlite3_backup] object B. 7641 ** ^If N is negative, all remaining source pages are copied. 7642 ** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 7643 ** are still more pages to be copied, then the function returns [SQLITE_OK]. 7644 ** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 7645 ** from source to destination, then it returns [SQLITE_DONE]. 7646 ** ^If an error occurs while running sqlite3_backup_step(B,N), 7647 ** then an [error code] is returned. ^As well as [SQLITE_OK] and 7648 ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 7649 ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 7650 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 7651 ** 7652 ** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 7653 ** <ol> 7654 ** <li> the destination database was opened read-only, or 7655 ** <li> the destination database is using write-ahead-log journaling 7656 ** and the destination and source page sizes differ, or 7657 ** <li> the destination database is an in-memory database and the 7658 ** destination and source page sizes differ. 7659 ** </ol>)^ 7660 ** 7661 ** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 7662 ** the [sqlite3_busy_handler | busy-handler function] 7663 ** is invoked (if one is specified). ^If the 7664 ** busy-handler returns non-zero before the lock is available, then 7665 ** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 7666 ** sqlite3_backup_step() can be retried later. ^If the source 7667 ** [database connection] 7668 ** is being used to write to the source database when sqlite3_backup_step() 7669 ** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 7670 ** case the call to sqlite3_backup_step() can be retried later on. ^(If 7671 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 7672 ** [SQLITE_READONLY] is returned, then 7673 ** there is no point in retrying the call to sqlite3_backup_step(). These 7674 ** errors are considered fatal.)^ The application must accept 7675 ** that the backup operation has failed and pass the backup operation handle 7676 ** to the sqlite3_backup_finish() to release associated resources. 7677 ** 7678 ** ^The first call to sqlite3_backup_step() obtains an exclusive lock 7679 ** on the destination file. ^The exclusive lock is not released until either 7680 ** sqlite3_backup_finish() is called or the backup operation is complete 7681 ** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 7682 ** sqlite3_backup_step() obtains a [shared lock] on the source database that 7683 ** lasts for the duration of the sqlite3_backup_step() call. 7684 ** ^Because the source database is not locked between calls to 7685 ** sqlite3_backup_step(), the source database may be modified mid-way 7686 ** through the backup process. ^If the source database is modified by an 7687 ** external process or via a database connection other than the one being 7688 ** used by the backup operation, then the backup will be automatically 7689 ** restarted by the next call to sqlite3_backup_step(). ^If the source 7690 ** database is modified by the using the same database connection as is used 7691 ** by the backup operation, then the backup database is automatically 7692 ** updated at the same time. 7693 ** 7694 ** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 7695 ** 7696 ** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 7697 ** application wishes to abandon the backup operation, the application 7698 ** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 7699 ** ^The sqlite3_backup_finish() interfaces releases all 7700 ** resources associated with the [sqlite3_backup] object. 7701 ** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 7702 ** active write-transaction on the destination database is rolled back. 7703 ** The [sqlite3_backup] object is invalid 7704 ** and may not be used following a call to sqlite3_backup_finish(). 7705 ** 7706 ** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 7707 ** sqlite3_backup_step() errors occurred, regardless or whether or not 7708 ** sqlite3_backup_step() completed. 7709 ** ^If an out-of-memory condition or IO error occurred during any prior 7710 ** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 7711 ** sqlite3_backup_finish() returns the corresponding [error code]. 7712 ** 7713 ** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 7714 ** is not a permanent error and does not affect the return value of 7715 ** sqlite3_backup_finish(). 7716 ** 7717 ** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]] 7718 ** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 7719 ** 7720 ** ^The sqlite3_backup_remaining() routine returns the number of pages still 7721 ** to be backed up at the conclusion of the most recent sqlite3_backup_step(). 7722 ** ^The sqlite3_backup_pagecount() routine returns the total number of pages 7723 ** in the source database at the conclusion of the most recent 7724 ** sqlite3_backup_step(). 7725 ** ^(The values returned by these functions are only updated by 7726 ** sqlite3_backup_step(). If the source database is modified in a way that 7727 ** changes the size of the source database or the number of pages remaining, 7728 ** those changes are not reflected in the output of sqlite3_backup_pagecount() 7729 ** and sqlite3_backup_remaining() until after the next 7730 ** sqlite3_backup_step().)^ 7731 ** 7732 ** <b>Concurrent Usage of Database Handles</b> 7733 ** 7734 ** ^The source [database connection] may be used by the application for other 7735 ** purposes while a backup operation is underway or being initialized. 7736 ** ^If SQLite is compiled and configured to support threadsafe database 7737 ** connections, then the source database connection may be used concurrently 7738 ** from within other threads. 7739 ** 7740 ** However, the application must guarantee that the destination 7741 ** [database connection] is not passed to any other API (by any thread) after 7742 ** sqlite3_backup_init() is called and before the corresponding call to 7743 ** sqlite3_backup_finish(). SQLite does not currently check to see 7744 ** if the application incorrectly accesses the destination [database connection] 7745 ** and so no error code is reported, but the operations may malfunction 7746 ** nevertheless. Use of the destination database connection while a 7747 ** backup is in progress might also also cause a mutex deadlock. 7748 ** 7749 ** If running in [shared cache mode], the application must 7750 ** guarantee that the shared cache used by the destination database 7751 ** is not accessed while the backup is running. In practice this means 7752 ** that the application must guarantee that the disk file being 7753 ** backed up to is not accessed by any connection within the process, 7754 ** not just the specific connection that was passed to sqlite3_backup_init(). 7755 ** 7756 ** The [sqlite3_backup] object itself is partially threadsafe. Multiple 7757 ** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 7758 ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 7759 ** APIs are not strictly speaking threadsafe. If they are invoked at the 7760 ** same time as another thread is invoking sqlite3_backup_step() it is 7761 ** possible that they return invalid values. 7762 */ 7763 SQLITE_API sqlite3_backup *sqlite3_backup_init( 7764 sqlite3 *pDest, /* Destination database handle */ 7765 const char *zDestName, /* Destination database name */ 7766 sqlite3 *pSource, /* Source database handle */ 7767 const char *zSourceName /* Source database name */ 7768 ); 7769 SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage); 7770 SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p); 7771 SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p); 7772 SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p); 7773 7774 /* 7775 ** CAPI3REF: Unlock Notification 7776 ** METHOD: sqlite3 7777 ** 7778 ** ^When running in shared-cache mode, a database operation may fail with 7779 ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 7780 ** individual tables within the shared-cache cannot be obtained. See 7781 ** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 7782 ** ^This API may be used to register a callback that SQLite will invoke 7783 ** when the connection currently holding the required lock relinquishes it. 7784 ** ^This API is only available if the library was compiled with the 7785 ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 7786 ** 7787 ** See Also: [Using the SQLite Unlock Notification Feature]. 7788 ** 7789 ** ^Shared-cache locks are released when a database connection concludes 7790 ** its current transaction, either by committing it or rolling it back. 7791 ** 7792 ** ^When a connection (known as the blocked connection) fails to obtain a 7793 ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 7794 ** identity of the database connection (the blocking connection) that 7795 ** has locked the required resource is stored internally. ^After an 7796 ** application receives an SQLITE_LOCKED error, it may call the 7797 ** sqlite3_unlock_notify() method with the blocked connection handle as 7798 ** the first argument to register for a callback that will be invoked 7799 ** when the blocking connections current transaction is concluded. ^The 7800 ** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 7801 ** call that concludes the blocking connections transaction. 7802 ** 7803 ** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 7804 ** there is a chance that the blocking connection will have already 7805 ** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 7806 ** If this happens, then the specified callback is invoked immediately, 7807 ** from within the call to sqlite3_unlock_notify().)^ 7808 ** 7809 ** ^If the blocked connection is attempting to obtain a write-lock on a 7810 ** shared-cache table, and more than one other connection currently holds 7811 ** a read-lock on the same table, then SQLite arbitrarily selects one of 7812 ** the other connections to use as the blocking connection. 7813 ** 7814 ** ^(There may be at most one unlock-notify callback registered by a 7815 ** blocked connection. If sqlite3_unlock_notify() is called when the 7816 ** blocked connection already has a registered unlock-notify callback, 7817 ** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 7818 ** called with a NULL pointer as its second argument, then any existing 7819 ** unlock-notify callback is canceled. ^The blocked connections 7820 ** unlock-notify callback may also be canceled by closing the blocked 7821 ** connection using [sqlite3_close()]. 7822 ** 7823 ** The unlock-notify callback is not reentrant. If an application invokes 7824 ** any sqlite3_xxx API functions from within an unlock-notify callback, a 7825 ** crash or deadlock may be the result. 7826 ** 7827 ** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 7828 ** returns SQLITE_OK. 7829 ** 7830 ** <b>Callback Invocation Details</b> 7831 ** 7832 ** When an unlock-notify callback is registered, the application provides a 7833 ** single void* pointer that is passed to the callback when it is invoked. 7834 ** However, the signature of the callback function allows SQLite to pass 7835 ** it an array of void* context pointers. The first argument passed to 7836 ** an unlock-notify callback is a pointer to an array of void* pointers, 7837 ** and the second is the number of entries in the array. 7838 ** 7839 ** When a blocking connections transaction is concluded, there may be 7840 ** more than one blocked connection that has registered for an unlock-notify 7841 ** callback. ^If two or more such blocked connections have specified the 7842 ** same callback function, then instead of invoking the callback function 7843 ** multiple times, it is invoked once with the set of void* context pointers 7844 ** specified by the blocked connections bundled together into an array. 7845 ** This gives the application an opportunity to prioritize any actions 7846 ** related to the set of unblocked database connections. 7847 ** 7848 ** <b>Deadlock Detection</b> 7849 ** 7850 ** Assuming that after registering for an unlock-notify callback a 7851 ** database waits for the callback to be issued before taking any further 7852 ** action (a reasonable assumption), then using this API may cause the 7853 ** application to deadlock. For example, if connection X is waiting for 7854 ** connection Y's transaction to be concluded, and similarly connection 7855 ** Y is waiting on connection X's transaction, then neither connection 7856 ** will proceed and the system may remain deadlocked indefinitely. 7857 ** 7858 ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 7859 ** detection. ^If a given call to sqlite3_unlock_notify() would put the 7860 ** system in a deadlocked state, then SQLITE_LOCKED is returned and no 7861 ** unlock-notify callback is registered. The system is said to be in 7862 ** a deadlocked state if connection A has registered for an unlock-notify 7863 ** callback on the conclusion of connection B's transaction, and connection 7864 ** B has itself registered for an unlock-notify callback when connection 7865 ** A's transaction is concluded. ^Indirect deadlock is also detected, so 7866 ** the system is also considered to be deadlocked if connection B has 7867 ** registered for an unlock-notify callback on the conclusion of connection 7868 ** C's transaction, where connection C is waiting on connection A. ^Any 7869 ** number of levels of indirection are allowed. 7870 ** 7871 ** <b>The "DROP TABLE" Exception</b> 7872 ** 7873 ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 7874 ** always appropriate to call sqlite3_unlock_notify(). There is however, 7875 ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 7876 ** SQLite checks if there are any currently executing SELECT statements 7877 ** that belong to the same connection. If there are, SQLITE_LOCKED is 7878 ** returned. In this case there is no "blocking connection", so invoking 7879 ** sqlite3_unlock_notify() results in the unlock-notify callback being 7880 ** invoked immediately. If the application then re-attempts the "DROP TABLE" 7881 ** or "DROP INDEX" query, an infinite loop might be the result. 7882 ** 7883 ** One way around this problem is to check the extended error code returned 7884 ** by an sqlite3_step() call. ^(If there is a blocking connection, then the 7885 ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 7886 ** the special "DROP TABLE/INDEX" case, the extended error code is just 7887 ** SQLITE_LOCKED.)^ 7888 */ 7889 SQLITE_API int sqlite3_unlock_notify( 7890 sqlite3 *pBlocked, /* Waiting connection */ 7891 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 7892 void *pNotifyArg /* Argument to pass to xNotify */ 7893 ); 7894 7895 7896 /* 7897 ** CAPI3REF: String Comparison 7898 ** 7899 ** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 7900 ** and extensions to compare the contents of two buffers containing UTF-8 7901 ** strings in a case-independent fashion, using the same definition of "case 7902 ** independence" that SQLite uses internally when comparing identifiers. 7903 */ 7904 SQLITE_API int sqlite3_stricmp(const char *, const char *); 7905 SQLITE_API int sqlite3_strnicmp(const char *, const char *, int); 7906 7907 /* 7908 ** CAPI3REF: String Globbing 7909 * 7910 ** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if 7911 ** string X matches the [GLOB] pattern P. 7912 ** ^The definition of [GLOB] pattern matching used in 7913 ** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the 7914 ** SQL dialect understood by SQLite. ^The [sqlite3_strglob(P,X)] function 7915 ** is case sensitive. 7916 ** 7917 ** Note that this routine returns zero on a match and non-zero if the strings 7918 ** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 7919 ** 7920 ** See also: [sqlite3_strlike()]. 7921 */ 7922 SQLITE_API int sqlite3_strglob(const char *zGlob, const char *zStr); 7923 7924 /* 7925 ** CAPI3REF: String LIKE Matching 7926 * 7927 ** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if 7928 ** string X matches the [LIKE] pattern P with escape character E. 7929 ** ^The definition of [LIKE] pattern matching used in 7930 ** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E" 7931 ** operator in the SQL dialect understood by SQLite. ^For "X LIKE P" without 7932 ** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0. 7933 ** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case 7934 ** insensitive - equivalent upper and lower case ASCII characters match 7935 ** one another. 7936 ** 7937 ** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though 7938 ** only ASCII characters are case folded. 7939 ** 7940 ** Note that this routine returns zero on a match and non-zero if the strings 7941 ** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 7942 ** 7943 ** See also: [sqlite3_strglob()]. 7944 */ 7945 SQLITE_API int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc); 7946 7947 /* 7948 ** CAPI3REF: Error Logging Interface 7949 ** 7950 ** ^The [sqlite3_log()] interface writes a message into the [error log] 7951 ** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 7952 ** ^If logging is enabled, the zFormat string and subsequent arguments are 7953 ** used with [sqlite3_snprintf()] to generate the final output string. 7954 ** 7955 ** The sqlite3_log() interface is intended for use by extensions such as 7956 ** virtual tables, collating functions, and SQL functions. While there is 7957 ** nothing to prevent an application from calling sqlite3_log(), doing so 7958 ** is considered bad form. 7959 ** 7960 ** The zFormat string must not be NULL. 7961 ** 7962 ** To avoid deadlocks and other threading problems, the sqlite3_log() routine 7963 ** will not use dynamically allocated memory. The log message is stored in 7964 ** a fixed-length buffer on the stack. If the log message is longer than 7965 ** a few hundred characters, it will be truncated to the length of the 7966 ** buffer. 7967 */ 7968 SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...); 7969 7970 /* 7971 ** CAPI3REF: Write-Ahead Log Commit Hook 7972 ** METHOD: sqlite3 7973 ** 7974 ** ^The [sqlite3_wal_hook()] function is used to register a callback that 7975 ** is invoked each time data is committed to a database in wal mode. 7976 ** 7977 ** ^(The callback is invoked by SQLite after the commit has taken place and 7978 ** the associated write-lock on the database released)^, so the implementation 7979 ** may read, write or [checkpoint] the database as required. 7980 ** 7981 ** ^The first parameter passed to the callback function when it is invoked 7982 ** is a copy of the third parameter passed to sqlite3_wal_hook() when 7983 ** registering the callback. ^The second is a copy of the database handle. 7984 ** ^The third parameter is the name of the database that was written to - 7985 ** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 7986 ** is the number of pages currently in the write-ahead log file, 7987 ** including those that were just committed. 7988 ** 7989 ** The callback function should normally return [SQLITE_OK]. ^If an error 7990 ** code is returned, that error will propagate back up through the 7991 ** SQLite code base to cause the statement that provoked the callback 7992 ** to report an error, though the commit will have still occurred. If the 7993 ** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 7994 ** that does not correspond to any valid SQLite error code, the results 7995 ** are undefined. 7996 ** 7997 ** A single database handle may have at most a single write-ahead log callback 7998 ** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 7999 ** previously registered write-ahead log callback. ^Note that the 8000 ** [sqlite3_wal_autocheckpoint()] interface and the 8001 ** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 8002 ** overwrite any prior [sqlite3_wal_hook()] settings. 8003 */ 8004 SQLITE_API void *sqlite3_wal_hook( 8005 sqlite3*, 8006 int(*)(void *,sqlite3*,const char*,int), 8007 void* 8008 ); 8009 8010 /* 8011 ** CAPI3REF: Configure an auto-checkpoint 8012 ** METHOD: sqlite3 8013 ** 8014 ** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 8015 ** [sqlite3_wal_hook()] that causes any database on [database connection] D 8016 ** to automatically [checkpoint] 8017 ** after committing a transaction if there are N or 8018 ** more frames in the [write-ahead log] file. ^Passing zero or 8019 ** a negative value as the nFrame parameter disables automatic 8020 ** checkpoints entirely. 8021 ** 8022 ** ^The callback registered by this function replaces any existing callback 8023 ** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 8024 ** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 8025 ** configured by this function. 8026 ** 8027 ** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 8028 ** from SQL. 8029 ** 8030 ** ^Checkpoints initiated by this mechanism are 8031 ** [sqlite3_wal_checkpoint_v2|PASSIVE]. 8032 ** 8033 ** ^Every new [database connection] defaults to having the auto-checkpoint 8034 ** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 8035 ** pages. The use of this interface 8036 ** is only necessary if the default setting is found to be suboptimal 8037 ** for a particular application. 8038 */ 8039 SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 8040 8041 /* 8042 ** CAPI3REF: Checkpoint a database 8043 ** METHOD: sqlite3 8044 ** 8045 ** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to 8046 ** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^ 8047 ** 8048 ** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the 8049 ** [write-ahead log] for database X on [database connection] D to be 8050 ** transferred into the database file and for the write-ahead log to 8051 ** be reset. See the [checkpointing] documentation for addition 8052 ** information. 8053 ** 8054 ** This interface used to be the only way to cause a checkpoint to 8055 ** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()] 8056 ** interface was added. This interface is retained for backwards 8057 ** compatibility and as a convenience for applications that need to manually 8058 ** start a callback but which do not need the full power (and corresponding 8059 ** complication) of [sqlite3_wal_checkpoint_v2()]. 8060 */ 8061 SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 8062 8063 /* 8064 ** CAPI3REF: Checkpoint a database 8065 ** METHOD: sqlite3 8066 ** 8067 ** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint 8068 ** operation on database X of [database connection] D in mode M. Status 8069 ** information is written back into integers pointed to by L and C.)^ 8070 ** ^(The M parameter must be a valid [checkpoint mode]:)^ 8071 ** 8072 ** <dl> 8073 ** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 8074 ** ^Checkpoint as many frames as possible without waiting for any database 8075 ** readers or writers to finish, then sync the database file if all frames 8076 ** in the log were checkpointed. ^The [busy-handler callback] 8077 ** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode. 8078 ** ^On the other hand, passive mode might leave the checkpoint unfinished 8079 ** if there are concurrent readers or writers. 8080 ** 8081 ** <dt>SQLITE_CHECKPOINT_FULL<dd> 8082 ** ^This mode blocks (it invokes the 8083 ** [sqlite3_busy_handler|busy-handler callback]) until there is no 8084 ** database writer and all readers are reading from the most recent database 8085 ** snapshot. ^It then checkpoints all frames in the log file and syncs the 8086 ** database file. ^This mode blocks new database writers while it is pending, 8087 ** but new database readers are allowed to continue unimpeded. 8088 ** 8089 ** <dt>SQLITE_CHECKPOINT_RESTART<dd> 8090 ** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition 8091 ** that after checkpointing the log file it blocks (calls the 8092 ** [busy-handler callback]) 8093 ** until all readers are reading from the database file only. ^This ensures 8094 ** that the next writer will restart the log file from the beginning. 8095 ** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new 8096 ** database writer attempts while it is pending, but does not impede readers. 8097 ** 8098 ** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd> 8099 ** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the 8100 ** addition that it also truncates the log file to zero bytes just prior 8101 ** to a successful return. 8102 ** </dl> 8103 ** 8104 ** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in 8105 ** the log file or to -1 if the checkpoint could not run because 8106 ** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not 8107 ** NULL,then *pnCkpt is set to the total number of checkpointed frames in the 8108 ** log file (including any that were already checkpointed before the function 8109 ** was called) or to -1 if the checkpoint could not run due to an error or 8110 ** because the database is not in WAL mode. ^Note that upon successful 8111 ** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been 8112 ** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero. 8113 ** 8114 ** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If 8115 ** any other process is running a checkpoint operation at the same time, the 8116 ** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a 8117 ** busy-handler configured, it will not be invoked in this case. 8118 ** 8119 ** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the 8120 ** exclusive "writer" lock on the database file. ^If the writer lock cannot be 8121 ** obtained immediately, and a busy-handler is configured, it is invoked and 8122 ** the writer lock retried until either the busy-handler returns 0 or the lock 8123 ** is successfully obtained. ^The busy-handler is also invoked while waiting for 8124 ** database readers as described above. ^If the busy-handler returns 0 before 8125 ** the writer lock is obtained or while waiting for database readers, the 8126 ** checkpoint operation proceeds from that point in the same way as 8127 ** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 8128 ** without blocking any further. ^SQLITE_BUSY is returned in this case. 8129 ** 8130 ** ^If parameter zDb is NULL or points to a zero length string, then the 8131 ** specified operation is attempted on all WAL databases [attached] to 8132 ** [database connection] db. In this case the 8133 ** values written to output parameters *pnLog and *pnCkpt are undefined. ^If 8134 ** an SQLITE_BUSY error is encountered when processing one or more of the 8135 ** attached WAL databases, the operation is still attempted on any remaining 8136 ** attached databases and SQLITE_BUSY is returned at the end. ^If any other 8137 ** error occurs while processing an attached database, processing is abandoned 8138 ** and the error code is returned to the caller immediately. ^If no error 8139 ** (SQLITE_BUSY or otherwise) is encountered while processing the attached 8140 ** databases, SQLITE_OK is returned. 8141 ** 8142 ** ^If database zDb is the name of an attached database that is not in WAL 8143 ** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If 8144 ** zDb is not NULL (or a zero length string) and is not the name of any 8145 ** attached database, SQLITE_ERROR is returned to the caller. 8146 ** 8147 ** ^Unless it returns SQLITE_MISUSE, 8148 ** the sqlite3_wal_checkpoint_v2() interface 8149 ** sets the error information that is queried by 8150 ** [sqlite3_errcode()] and [sqlite3_errmsg()]. 8151 ** 8152 ** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface 8153 ** from SQL. 8154 */ 8155 SQLITE_API int sqlite3_wal_checkpoint_v2( 8156 sqlite3 *db, /* Database handle */ 8157 const char *zDb, /* Name of attached database (or NULL) */ 8158 int eMode, /* SQLITE_CHECKPOINT_* value */ 8159 int *pnLog, /* OUT: Size of WAL log in frames */ 8160 int *pnCkpt /* OUT: Total number of frames checkpointed */ 8161 ); 8162 8163 /* 8164 ** CAPI3REF: Checkpoint Mode Values 8165 ** KEYWORDS: {checkpoint mode} 8166 ** 8167 ** These constants define all valid values for the "checkpoint mode" passed 8168 ** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface. 8169 ** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the 8170 ** meaning of each of these checkpoint modes. 8171 */ 8172 #define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */ 8173 #define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */ 8174 #define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */ 8175 #define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */ 8176 8177 /* 8178 ** CAPI3REF: Virtual Table Interface Configuration 8179 ** 8180 ** This function may be called by either the [xConnect] or [xCreate] method 8181 ** of a [virtual table] implementation to configure 8182 ** various facets of the virtual table interface. 8183 ** 8184 ** If this interface is invoked outside the context of an xConnect or 8185 ** xCreate virtual table method then the behavior is undefined. 8186 ** 8187 ** At present, there is only one option that may be configured using 8188 ** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 8189 ** may be added in the future. 8190 */ 8191 SQLITE_API int sqlite3_vtab_config(sqlite3*, int op, ...); 8192 8193 /* 8194 ** CAPI3REF: Virtual Table Configuration Options 8195 ** 8196 ** These macros define the various options to the 8197 ** [sqlite3_vtab_config()] interface that [virtual table] implementations 8198 ** can use to customize and optimize their behavior. 8199 ** 8200 ** <dl> 8201 ** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 8202 ** <dd>Calls of the form 8203 ** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 8204 ** where X is an integer. If X is zero, then the [virtual table] whose 8205 ** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 8206 ** support constraints. In this configuration (which is the default) if 8207 ** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 8208 ** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 8209 ** specified as part of the users SQL statement, regardless of the actual 8210 ** ON CONFLICT mode specified. 8211 ** 8212 ** If X is non-zero, then the virtual table implementation guarantees 8213 ** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 8214 ** any modifications to internal or persistent data structures have been made. 8215 ** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 8216 ** is able to roll back a statement or database transaction, and abandon 8217 ** or continue processing the current SQL statement as appropriate. 8218 ** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 8219 ** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 8220 ** had been ABORT. 8221 ** 8222 ** Virtual table implementations that are required to handle OR REPLACE 8223 ** must do so within the [xUpdate] method. If a call to the 8224 ** [sqlite3_vtab_on_conflict()] function indicates that the current ON 8225 ** CONFLICT policy is REPLACE, the virtual table implementation should 8226 ** silently replace the appropriate rows within the xUpdate callback and 8227 ** return SQLITE_OK. Or, if this is not possible, it may return 8228 ** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 8229 ** constraint handling. 8230 ** </dl> 8231 */ 8232 #define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 8233 8234 /* 8235 ** CAPI3REF: Determine The Virtual Table Conflict Policy 8236 ** 8237 ** This function may only be called from within a call to the [xUpdate] method 8238 ** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 8239 ** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 8240 ** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 8241 ** of the SQL statement that triggered the call to the [xUpdate] method of the 8242 ** [virtual table]. 8243 */ 8244 SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *); 8245 8246 /* 8247 ** CAPI3REF: Conflict resolution modes 8248 ** KEYWORDS: {conflict resolution mode} 8249 ** 8250 ** These constants are returned by [sqlite3_vtab_on_conflict()] to 8251 ** inform a [virtual table] implementation what the [ON CONFLICT] mode 8252 ** is for the SQL statement being evaluated. 8253 ** 8254 ** Note that the [SQLITE_IGNORE] constant is also used as a potential 8255 ** return value from the [sqlite3_set_authorizer()] callback and that 8256 ** [SQLITE_ABORT] is also a [result code]. 8257 */ 8258 #define SQLITE_ROLLBACK 1 8259 /* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 8260 #define SQLITE_FAIL 3 8261 /* #define SQLITE_ABORT 4 // Also an error code */ 8262 #define SQLITE_REPLACE 5 8263 8264 /* 8265 ** CAPI3REF: Prepared Statement Scan Status Opcodes 8266 ** KEYWORDS: {scanstatus options} 8267 ** 8268 ** The following constants can be used for the T parameter to the 8269 ** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a 8270 ** different metric for sqlite3_stmt_scanstatus() to return. 8271 ** 8272 ** When the value returned to V is a string, space to hold that string is 8273 ** managed by the prepared statement S and will be automatically freed when 8274 ** S is finalized. 8275 ** 8276 ** <dl> 8277 ** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt> 8278 ** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be 8279 ** set to the total number of times that the X-th loop has run.</dd> 8280 ** 8281 ** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt> 8282 ** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set 8283 ** to the total number of rows examined by all iterations of the X-th loop.</dd> 8284 ** 8285 ** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt> 8286 ** <dd>^The "double" variable pointed to by the T parameter will be set to the 8287 ** query planner's estimate for the average number of rows output from each 8288 ** iteration of the X-th loop. If the query planner's estimates was accurate, 8289 ** then this value will approximate the quotient NVISIT/NLOOP and the 8290 ** product of this value for all prior loops with the same SELECTID will 8291 ** be the NLOOP value for the current loop. 8292 ** 8293 ** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt> 8294 ** <dd>^The "const char *" variable pointed to by the T parameter will be set 8295 ** to a zero-terminated UTF-8 string containing the name of the index or table 8296 ** used for the X-th loop. 8297 ** 8298 ** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt> 8299 ** <dd>^The "const char *" variable pointed to by the T parameter will be set 8300 ** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN] 8301 ** description for the X-th loop. 8302 ** 8303 ** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt> 8304 ** <dd>^The "int" variable pointed to by the T parameter will be set to the 8305 ** "select-id" for the X-th loop. The select-id identifies which query or 8306 ** subquery the loop is part of. The main query has a select-id of zero. 8307 ** The select-id is the same value as is output in the first column 8308 ** of an [EXPLAIN QUERY PLAN] query. 8309 ** </dl> 8310 */ 8311 #define SQLITE_SCANSTAT_NLOOP 0 8312 #define SQLITE_SCANSTAT_NVISIT 1 8313 #define SQLITE_SCANSTAT_EST 2 8314 #define SQLITE_SCANSTAT_NAME 3 8315 #define SQLITE_SCANSTAT_EXPLAIN 4 8316 #define SQLITE_SCANSTAT_SELECTID 5 8317 8318 /* 8319 ** CAPI3REF: Prepared Statement Scan Status 8320 ** METHOD: sqlite3_stmt 8321 ** 8322 ** This interface returns information about the predicted and measured 8323 ** performance for pStmt. Advanced applications can use this 8324 ** interface to compare the predicted and the measured performance and 8325 ** issue warnings and/or rerun [ANALYZE] if discrepancies are found. 8326 ** 8327 ** Since this interface is expected to be rarely used, it is only 8328 ** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS] 8329 ** compile-time option. 8330 ** 8331 ** The "iScanStatusOp" parameter determines which status information to return. 8332 ** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior 8333 ** of this interface is undefined. 8334 ** ^The requested measurement is written into a variable pointed to by 8335 ** the "pOut" parameter. 8336 ** Parameter "idx" identifies the specific loop to retrieve statistics for. 8337 ** Loops are numbered starting from zero. ^If idx is out of range - less than 8338 ** zero or greater than or equal to the total number of loops used to implement 8339 ** the statement - a non-zero value is returned and the variable that pOut 8340 ** points to is unchanged. 8341 ** 8342 ** ^Statistics might not be available for all loops in all statements. ^In cases 8343 ** where there exist loops with no available statistics, this function behaves 8344 ** as if the loop did not exist - it returns non-zero and leave the variable 8345 ** that pOut points to unchanged. 8346 ** 8347 ** See also: [sqlite3_stmt_scanstatus_reset()] 8348 */ 8349 SQLITE_API int sqlite3_stmt_scanstatus( 8350 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */ 8351 int idx, /* Index of loop to report on */ 8352 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */ 8353 void *pOut /* Result written here */ 8354 ); 8355 8356 /* 8357 ** CAPI3REF: Zero Scan-Status Counters 8358 ** METHOD: sqlite3_stmt 8359 ** 8360 ** ^Zero all [sqlite3_stmt_scanstatus()] related event counters. 8361 ** 8362 ** This API is only available if the library is built with pre-processor 8363 ** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined. 8364 */ 8365 SQLITE_API void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*); 8366 8367 /* 8368 ** CAPI3REF: Flush caches to disk mid-transaction 8369 ** 8370 ** ^If a write-transaction is open on [database connection] D when the 8371 ** [sqlite3_db_cacheflush(D)] interface invoked, any dirty 8372 ** pages in the pager-cache that are not currently in use are written out 8373 ** to disk. A dirty page may be in use if a database cursor created by an 8374 ** active SQL statement is reading from it, or if it is page 1 of a database 8375 ** file (page 1 is always "in use"). ^The [sqlite3_db_cacheflush(D)] 8376 ** interface flushes caches for all schemas - "main", "temp", and 8377 ** any [attached] databases. 8378 ** 8379 ** ^If this function needs to obtain extra database locks before dirty pages 8380 ** can be flushed to disk, it does so. ^If those locks cannot be obtained 8381 ** immediately and there is a busy-handler callback configured, it is invoked 8382 ** in the usual manner. ^If the required lock still cannot be obtained, then 8383 ** the database is skipped and an attempt made to flush any dirty pages 8384 ** belonging to the next (if any) database. ^If any databases are skipped 8385 ** because locks cannot be obtained, but no other error occurs, this 8386 ** function returns SQLITE_BUSY. 8387 ** 8388 ** ^If any other error occurs while flushing dirty pages to disk (for 8389 ** example an IO error or out-of-memory condition), then processing is 8390 ** abandoned and an SQLite [error code] is returned to the caller immediately. 8391 ** 8392 ** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK. 8393 ** 8394 ** ^This function does not set the database handle error code or message 8395 ** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions. 8396 */ 8397 SQLITE_API int sqlite3_db_cacheflush(sqlite3*); 8398 8399 /* 8400 ** CAPI3REF: The pre-update hook. 8401 ** 8402 ** ^These interfaces are only available if SQLite is compiled using the 8403 ** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option. 8404 ** 8405 ** ^The [sqlite3_preupdate_hook()] interface registers a callback function 8406 ** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation 8407 ** on a database table. 8408 ** ^At most one preupdate hook may be registered at a time on a single 8409 ** [database connection]; each call to [sqlite3_preupdate_hook()] overrides 8410 ** the previous setting. 8411 ** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()] 8412 ** with a NULL pointer as the second parameter. 8413 ** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as 8414 ** the first parameter to callbacks. 8415 ** 8416 ** ^The preupdate hook only fires for changes to real database tables; the 8417 ** preupdate hook is not invoked for changes to [virtual tables] or to 8418 ** system tables like sqlite_master or sqlite_stat1. 8419 ** 8420 ** ^The second parameter to the preupdate callback is a pointer to 8421 ** the [database connection] that registered the preupdate hook. 8422 ** ^The third parameter to the preupdate callback is one of the constants 8423 ** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the 8424 ** kind of update operation that is about to occur. 8425 ** ^(The fourth parameter to the preupdate callback is the name of the 8426 ** database within the database connection that is being modified. This 8427 ** will be "main" for the main database or "temp" for TEMP tables or 8428 ** the name given after the AS keyword in the [ATTACH] statement for attached 8429 ** databases.)^ 8430 ** ^The fifth parameter to the preupdate callback is the name of the 8431 ** table that is being modified. 8432 ** 8433 ** For an UPDATE or DELETE operation on a [rowid table], the sixth 8434 ** parameter passed to the preupdate callback is the initial [rowid] of the 8435 ** row being modified or deleted. For an INSERT operation on a rowid table, 8436 ** or any operation on a WITHOUT ROWID table, the value of the sixth 8437 ** parameter is undefined. For an INSERT or UPDATE on a rowid table the 8438 ** seventh parameter is the final rowid value of the row being inserted 8439 ** or updated. The value of the seventh parameter passed to the callback 8440 ** function is not defined for operations on WITHOUT ROWID tables, or for 8441 ** INSERT operations on rowid tables. 8442 ** 8443 ** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()], 8444 ** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces 8445 ** provide additional information about a preupdate event. These routines 8446 ** may only be called from within a preupdate callback. Invoking any of 8447 ** these routines from outside of a preupdate callback or with a 8448 ** [database connection] pointer that is different from the one supplied 8449 ** to the preupdate callback results in undefined and probably undesirable 8450 ** behavior. 8451 ** 8452 ** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns 8453 ** in the row that is being inserted, updated, or deleted. 8454 ** 8455 ** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to 8456 ** a [protected sqlite3_value] that contains the value of the Nth column of 8457 ** the table row before it is updated. The N parameter must be between 0 8458 ** and one less than the number of columns or the behavior will be 8459 ** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE 8460 ** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the 8461 ** behavior is undefined. The [sqlite3_value] that P points to 8462 ** will be destroyed when the preupdate callback returns. 8463 ** 8464 ** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to 8465 ** a [protected sqlite3_value] that contains the value of the Nth column of 8466 ** the table row after it is updated. The N parameter must be between 0 8467 ** and one less than the number of columns or the behavior will be 8468 ** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE 8469 ** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the 8470 ** behavior is undefined. The [sqlite3_value] that P points to 8471 ** will be destroyed when the preupdate callback returns. 8472 ** 8473 ** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate 8474 ** callback was invoked as a result of a direct insert, update, or delete 8475 ** operation; or 1 for inserts, updates, or deletes invoked by top-level 8476 ** triggers; or 2 for changes resulting from triggers called by top-level 8477 ** triggers; and so forth. 8478 ** 8479 ** See also: [sqlite3_update_hook()] 8480 */ 8481 #if defined(SQLITE_ENABLE_PREUPDATE_HOOK) 8482 SQLITE_API void *sqlite3_preupdate_hook( 8483 sqlite3 *db, 8484 void(*xPreUpdate)( 8485 void *pCtx, /* Copy of third arg to preupdate_hook() */ 8486 sqlite3 *db, /* Database handle */ 8487 int op, /* SQLITE_UPDATE, DELETE or INSERT */ 8488 char const *zDb, /* Database name */ 8489 char const *zName, /* Table name */ 8490 sqlite3_int64 iKey1, /* Rowid of row about to be deleted/updated */ 8491 sqlite3_int64 iKey2 /* New rowid value (for a rowid UPDATE) */ 8492 ), 8493 void* 8494 ); 8495 SQLITE_API int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **); 8496 SQLITE_API int sqlite3_preupdate_count(sqlite3 *); 8497 SQLITE_API int sqlite3_preupdate_depth(sqlite3 *); 8498 SQLITE_API int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **); 8499 #endif 8500 8501 /* 8502 ** CAPI3REF: Low-level system error code 8503 ** 8504 ** ^Attempt to return the underlying operating system error code or error 8505 ** number that caused the most recent I/O error or failure to open a file. 8506 ** The return value is OS-dependent. For example, on unix systems, after 8507 ** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be 8508 ** called to get back the underlying "errno" that caused the problem, such 8509 ** as ENOSPC, EAUTH, EISDIR, and so forth. 8510 */ 8511 SQLITE_API int sqlite3_system_errno(sqlite3*); 8512 8513 /* 8514 ** CAPI3REF: Database Snapshot 8515 ** KEYWORDS: {snapshot} {sqlite3_snapshot} 8516 ** EXPERIMENTAL 8517 ** 8518 ** An instance of the snapshot object records the state of a [WAL mode] 8519 ** database for some specific point in history. 8520 ** 8521 ** In [WAL mode], multiple [database connections] that are open on the 8522 ** same database file can each be reading a different historical version 8523 ** of the database file. When a [database connection] begins a read 8524 ** transaction, that connection sees an unchanging copy of the database 8525 ** as it existed for the point in time when the transaction first started. 8526 ** Subsequent changes to the database from other connections are not seen 8527 ** by the reader until a new read transaction is started. 8528 ** 8529 ** The sqlite3_snapshot object records state information about an historical 8530 ** version of the database file so that it is possible to later open a new read 8531 ** transaction that sees that historical version of the database rather than 8532 ** the most recent version. 8533 ** 8534 ** The constructor for this object is [sqlite3_snapshot_get()]. The 8535 ** [sqlite3_snapshot_open()] method causes a fresh read transaction to refer 8536 ** to an historical snapshot (if possible). The destructor for 8537 ** sqlite3_snapshot objects is [sqlite3_snapshot_free()]. 8538 */ 8539 typedef struct sqlite3_snapshot { 8540 unsigned char hidden[48]; 8541 } sqlite3_snapshot; 8542 8543 /* 8544 ** CAPI3REF: Record A Database Snapshot 8545 ** EXPERIMENTAL 8546 ** 8547 ** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a 8548 ** new [sqlite3_snapshot] object that records the current state of 8549 ** schema S in database connection D. ^On success, the 8550 ** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly 8551 ** created [sqlite3_snapshot] object into *P and returns SQLITE_OK. 8552 ** If there is not already a read-transaction open on schema S when 8553 ** this function is called, one is opened automatically. 8554 ** 8555 ** The following must be true for this function to succeed. If any of 8556 ** the following statements are false when sqlite3_snapshot_get() is 8557 ** called, SQLITE_ERROR is returned. The final value of *P is undefined 8558 ** in this case. 8559 ** 8560 ** <ul> 8561 ** <li> The database handle must be in [autocommit mode]. 8562 ** 8563 ** <li> Schema S of [database connection] D must be a [WAL mode] database. 8564 ** 8565 ** <li> There must not be a write transaction open on schema S of database 8566 ** connection D. 8567 ** 8568 ** <li> One or more transactions must have been written to the current wal 8569 ** file since it was created on disk (by any connection). This means 8570 ** that a snapshot cannot be taken on a wal mode database with no wal 8571 ** file immediately after it is first opened. At least one transaction 8572 ** must be written to it first. 8573 ** </ul> 8574 ** 8575 ** This function may also return SQLITE_NOMEM. If it is called with the 8576 ** database handle in autocommit mode but fails for some other reason, 8577 ** whether or not a read transaction is opened on schema S is undefined. 8578 ** 8579 ** The [sqlite3_snapshot] object returned from a successful call to 8580 ** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()] 8581 ** to avoid a memory leak. 8582 ** 8583 ** The [sqlite3_snapshot_get()] interface is only available when the 8584 ** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8585 */ 8586 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_get( 8587 sqlite3 *db, 8588 const char *zSchema, 8589 sqlite3_snapshot **ppSnapshot 8590 ); 8591 8592 /* 8593 ** CAPI3REF: Start a read transaction on an historical snapshot 8594 ** EXPERIMENTAL 8595 ** 8596 ** ^The [sqlite3_snapshot_open(D,S,P)] interface starts a 8597 ** read transaction for schema S of 8598 ** [database connection] D such that the read transaction 8599 ** refers to historical [snapshot] P, rather than the most 8600 ** recent change to the database. 8601 ** ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK on success 8602 ** or an appropriate [error code] if it fails. 8603 ** 8604 ** ^In order to succeed, a call to [sqlite3_snapshot_open(D,S,P)] must be 8605 ** the first operation following the [BEGIN] that takes the schema S 8606 ** out of [autocommit mode]. 8607 ** ^In other words, schema S must not currently be in 8608 ** a transaction for [sqlite3_snapshot_open(D,S,P)] to work, but the 8609 ** database connection D must be out of [autocommit mode]. 8610 ** ^A [snapshot] will fail to open if it has been overwritten by a 8611 ** [checkpoint]. 8612 ** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the 8613 ** database connection D does not know that the database file for 8614 ** schema S is in [WAL mode]. A database connection might not know 8615 ** that the database file is in [WAL mode] if there has been no prior 8616 ** I/O on that database connection, or if the database entered [WAL mode] 8617 ** after the most recent I/O on the database connection.)^ 8618 ** (Hint: Run "[PRAGMA application_id]" against a newly opened 8619 ** database connection in order to make it ready to use snapshots.) 8620 ** 8621 ** The [sqlite3_snapshot_open()] interface is only available when the 8622 ** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8623 */ 8624 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_open( 8625 sqlite3 *db, 8626 const char *zSchema, 8627 sqlite3_snapshot *pSnapshot 8628 ); 8629 8630 /* 8631 ** CAPI3REF: Destroy a snapshot 8632 ** EXPERIMENTAL 8633 ** 8634 ** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P. 8635 ** The application must eventually free every [sqlite3_snapshot] object 8636 ** using this routine to avoid a memory leak. 8637 ** 8638 ** The [sqlite3_snapshot_free()] interface is only available when the 8639 ** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8640 */ 8641 SQLITE_API SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*); 8642 8643 /* 8644 ** CAPI3REF: Compare the ages of two snapshot handles. 8645 ** EXPERIMENTAL 8646 ** 8647 ** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages 8648 ** of two valid snapshot handles. 8649 ** 8650 ** If the two snapshot handles are not associated with the same database 8651 ** file, the result of the comparison is undefined. 8652 ** 8653 ** Additionally, the result of the comparison is only valid if both of the 8654 ** snapshot handles were obtained by calling sqlite3_snapshot_get() since the 8655 ** last time the wal file was deleted. The wal file is deleted when the 8656 ** database is changed back to rollback mode or when the number of database 8657 ** clients drops to zero. If either snapshot handle was obtained before the 8658 ** wal file was last deleted, the value returned by this function 8659 ** is undefined. 8660 ** 8661 ** Otherwise, this API returns a negative value if P1 refers to an older 8662 ** snapshot than P2, zero if the two handles refer to the same database 8663 ** snapshot, and a positive value if P1 is a newer snapshot than P2. 8664 */ 8665 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp( 8666 sqlite3_snapshot *p1, 8667 sqlite3_snapshot *p2 8668 ); 8669 8670 /* 8671 ** CAPI3REF: Recover snapshots from a wal file 8672 ** EXPERIMENTAL 8673 ** 8674 ** If all connections disconnect from a database file but do not perform 8675 ** a checkpoint, the existing wal file is opened along with the database 8676 ** file the next time the database is opened. At this point it is only 8677 ** possible to successfully call sqlite3_snapshot_open() to open the most 8678 ** recent snapshot of the database (the one at the head of the wal file), 8679 ** even though the wal file may contain other valid snapshots for which 8680 ** clients have sqlite3_snapshot handles. 8681 ** 8682 ** This function attempts to scan the wal file associated with database zDb 8683 ** of database handle db and make all valid snapshots available to 8684 ** sqlite3_snapshot_open(). It is an error if there is already a read 8685 ** transaction open on the database, or if the database is not a wal mode 8686 ** database. 8687 ** 8688 ** SQLITE_OK is returned if successful, or an SQLite error code otherwise. 8689 */ 8690 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb); 8691 8692 /* 8693 ** Undo the hack that converts floating point types to integer for 8694 ** builds on processors without floating point support. 8695 */ 8696 #ifdef SQLITE_OMIT_FLOATING_POINT 8697 # undef double 8698 #endif 8699 8700 #ifdef __cplusplus 8701 } /* End of the 'extern "C"' block */ 8702 #endif 8703 #endif /* SQLITE3_H */ 8704 8705 /******** Begin file sqlite3rtree.h *********/ 8706 /* 8707 ** 2010 August 30 8708 ** 8709 ** The author disclaims copyright to this source code. In place of 8710 ** a legal notice, here is a blessing: 8711 ** 8712 ** May you do good and not evil. 8713 ** May you find forgiveness for yourself and forgive others. 8714 ** May you share freely, never taking more than you give. 8715 ** 8716 ************************************************************************* 8717 */ 8718 8719 #ifndef _SQLITE3RTREE_H_ 8720 #define _SQLITE3RTREE_H_ 8721 8722 8723 #ifdef __cplusplus 8724 extern "C" { 8725 #endif 8726 8727 typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry; 8728 typedef struct sqlite3_rtree_query_info sqlite3_rtree_query_info; 8729 8730 /* The double-precision datatype used by RTree depends on the 8731 ** SQLITE_RTREE_INT_ONLY compile-time option. 8732 */ 8733 #ifdef SQLITE_RTREE_INT_ONLY 8734 typedef sqlite3_int64 sqlite3_rtree_dbl; 8735 #else 8736 typedef double sqlite3_rtree_dbl; 8737 #endif 8738 8739 /* 8740 ** Register a geometry callback named zGeom that can be used as part of an 8741 ** R-Tree geometry query as follows: 8742 ** 8743 ** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...) 8744 */ 8745 SQLITE_API int sqlite3_rtree_geometry_callback( 8746 sqlite3 *db, 8747 const char *zGeom, 8748 int (*xGeom)(sqlite3_rtree_geometry*, int, sqlite3_rtree_dbl*,int*), 8749 void *pContext 8750 ); 8751 8752 8753 /* 8754 ** A pointer to a structure of the following type is passed as the first 8755 ** argument to callbacks registered using rtree_geometry_callback(). 8756 */ 8757 struct sqlite3_rtree_geometry { 8758 void *pContext; /* Copy of pContext passed to s_r_g_c() */ 8759 int nParam; /* Size of array aParam[] */ 8760 sqlite3_rtree_dbl *aParam; /* Parameters passed to SQL geom function */ 8761 void *pUser; /* Callback implementation user data */ 8762 void (*xDelUser)(void *); /* Called by SQLite to clean up pUser */ 8763 }; 8764 8765 /* 8766 ** Register a 2nd-generation geometry callback named zScore that can be 8767 ** used as part of an R-Tree geometry query as follows: 8768 ** 8769 ** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zQueryFunc(... params ...) 8770 */ 8771 SQLITE_API int sqlite3_rtree_query_callback( 8772 sqlite3 *db, 8773 const char *zQueryFunc, 8774 int (*xQueryFunc)(sqlite3_rtree_query_info*), 8775 void *pContext, 8776 void (*xDestructor)(void*) 8777 ); 8778 8779 8780 /* 8781 ** A pointer to a structure of the following type is passed as the 8782 ** argument to scored geometry callback registered using 8783 ** sqlite3_rtree_query_callback(). 8784 ** 8785 ** Note that the first 5 fields of this structure are identical to 8786 ** sqlite3_rtree_geometry. This structure is a subclass of 8787 ** sqlite3_rtree_geometry. 8788 */ 8789 struct sqlite3_rtree_query_info { 8790 void *pContext; /* pContext from when function registered */ 8791 int nParam; /* Number of function parameters */ 8792 sqlite3_rtree_dbl *aParam; /* value of function parameters */ 8793 void *pUser; /* callback can use this, if desired */ 8794 void (*xDelUser)(void*); /* function to free pUser */ 8795 sqlite3_rtree_dbl *aCoord; /* Coordinates of node or entry to check */ 8796 unsigned int *anQueue; /* Number of pending entries in the queue */ 8797 int nCoord; /* Number of coordinates */ 8798 int iLevel; /* Level of current node or entry */ 8799 int mxLevel; /* The largest iLevel value in the tree */ 8800 sqlite3_int64 iRowid; /* Rowid for current entry */ 8801 sqlite3_rtree_dbl rParentScore; /* Score of parent node */ 8802 int eParentWithin; /* Visibility of parent node */ 8803 int eWithin; /* OUT: Visiblity */ 8804 sqlite3_rtree_dbl rScore; /* OUT: Write the score here */ 8805 /* The following fields are only available in 3.8.11 and later */ 8806 sqlite3_value **apSqlParam; /* Original SQL values of parameters */ 8807 }; 8808 8809 /* 8810 ** Allowed values for sqlite3_rtree_query.eWithin and .eParentWithin. 8811 */ 8812 #define NOT_WITHIN 0 /* Object completely outside of query region */ 8813 #define PARTLY_WITHIN 1 /* Object partially overlaps query region */ 8814 #define FULLY_WITHIN 2 /* Object fully contained within query region */ 8815 8816 8817 #ifdef __cplusplus 8818 } /* end of the 'extern "C"' block */ 8819 #endif 8820 8821 #endif /* ifndef _SQLITE3RTREE_H_ */ 8822 8823 /******** End of sqlite3rtree.h *********/ 8824 /******** Begin file sqlite3session.h *********/ 8825 8826 #if !defined(__SQLITESESSION_H_) && defined(SQLITE_ENABLE_SESSION) 8827 #define __SQLITESESSION_H_ 1 8828 8829 /* 8830 ** Make sure we can call this stuff from C++. 8831 */ 8832 #ifdef __cplusplus 8833 extern "C" { 8834 #endif 8835 8836 8837 /* 8838 ** CAPI3REF: Session Object Handle 8839 */ 8840 typedef struct sqlite3_session sqlite3_session; 8841 8842 /* 8843 ** CAPI3REF: Changeset Iterator Handle 8844 */ 8845 typedef struct sqlite3_changeset_iter sqlite3_changeset_iter; 8846 8847 /* 8848 ** CAPI3REF: Create A New Session Object 8849 ** 8850 ** Create a new session object attached to database handle db. If successful, 8851 ** a pointer to the new object is written to *ppSession and SQLITE_OK is 8852 ** returned. If an error occurs, *ppSession is set to NULL and an SQLite 8853 ** error code (e.g. SQLITE_NOMEM) is returned. 8854 ** 8855 ** It is possible to create multiple session objects attached to a single 8856 ** database handle. 8857 ** 8858 ** Session objects created using this function should be deleted using the 8859 ** [sqlite3session_delete()] function before the database handle that they 8860 ** are attached to is itself closed. If the database handle is closed before 8861 ** the session object is deleted, then the results of calling any session 8862 ** module function, including [sqlite3session_delete()] on the session object 8863 ** are undefined. 8864 ** 8865 ** Because the session module uses the [sqlite3_preupdate_hook()] API, it 8866 ** is not possible for an application to register a pre-update hook on a 8867 ** database handle that has one or more session objects attached. Nor is 8868 ** it possible to create a session object attached to a database handle for 8869 ** which a pre-update hook is already defined. The results of attempting 8870 ** either of these things are undefined. 8871 ** 8872 ** The session object will be used to create changesets for tables in 8873 ** database zDb, where zDb is either "main", or "temp", or the name of an 8874 ** attached database. It is not an error if database zDb is not attached 8875 ** to the database when the session object is created. 8876 */ 8877 SQLITE_API int sqlite3session_create( 8878 sqlite3 *db, /* Database handle */ 8879 const char *zDb, /* Name of db (e.g. "main") */ 8880 sqlite3_session **ppSession /* OUT: New session object */ 8881 ); 8882 8883 /* 8884 ** CAPI3REF: Delete A Session Object 8885 ** 8886 ** Delete a session object previously allocated using 8887 ** [sqlite3session_create()]. Once a session object has been deleted, the 8888 ** results of attempting to use pSession with any other session module 8889 ** function are undefined. 8890 ** 8891 ** Session objects must be deleted before the database handle to which they 8892 ** are attached is closed. Refer to the documentation for 8893 ** [sqlite3session_create()] for details. 8894 */ 8895 SQLITE_API void sqlite3session_delete(sqlite3_session *pSession); 8896 8897 8898 /* 8899 ** CAPI3REF: Enable Or Disable A Session Object 8900 ** 8901 ** Enable or disable the recording of changes by a session object. When 8902 ** enabled, a session object records changes made to the database. When 8903 ** disabled - it does not. A newly created session object is enabled. 8904 ** Refer to the documentation for [sqlite3session_changeset()] for further 8905 ** details regarding how enabling and disabling a session object affects 8906 ** the eventual changesets. 8907 ** 8908 ** Passing zero to this function disables the session. Passing a value 8909 ** greater than zero enables it. Passing a value less than zero is a 8910 ** no-op, and may be used to query the current state of the session. 8911 ** 8912 ** The return value indicates the final state of the session object: 0 if 8913 ** the session is disabled, or 1 if it is enabled. 8914 */ 8915 SQLITE_API int sqlite3session_enable(sqlite3_session *pSession, int bEnable); 8916 8917 /* 8918 ** CAPI3REF: Set Or Clear the Indirect Change Flag 8919 ** 8920 ** Each change recorded by a session object is marked as either direct or 8921 ** indirect. A change is marked as indirect if either: 8922 ** 8923 ** <ul> 8924 ** <li> The session object "indirect" flag is set when the change is 8925 ** made, or 8926 ** <li> The change is made by an SQL trigger or foreign key action 8927 ** instead of directly as a result of a users SQL statement. 8928 ** </ul> 8929 ** 8930 ** If a single row is affected by more than one operation within a session, 8931 ** then the change is considered indirect if all operations meet the criteria 8932 ** for an indirect change above, or direct otherwise. 8933 ** 8934 ** This function is used to set, clear or query the session object indirect 8935 ** flag. If the second argument passed to this function is zero, then the 8936 ** indirect flag is cleared. If it is greater than zero, the indirect flag 8937 ** is set. Passing a value less than zero does not modify the current value 8938 ** of the indirect flag, and may be used to query the current state of the 8939 ** indirect flag for the specified session object. 8940 ** 8941 ** The return value indicates the final state of the indirect flag: 0 if 8942 ** it is clear, or 1 if it is set. 8943 */ 8944 SQLITE_API int sqlite3session_indirect(sqlite3_session *pSession, int bIndirect); 8945 8946 /* 8947 ** CAPI3REF: Attach A Table To A Session Object 8948 ** 8949 ** If argument zTab is not NULL, then it is the name of a table to attach 8950 ** to the session object passed as the first argument. All subsequent changes 8951 ** made to the table while the session object is enabled will be recorded. See 8952 ** documentation for [sqlite3session_changeset()] for further details. 8953 ** 8954 ** Or, if argument zTab is NULL, then changes are recorded for all tables 8955 ** in the database. If additional tables are added to the database (by 8956 ** executing "CREATE TABLE" statements) after this call is made, changes for 8957 ** the new tables are also recorded. 8958 ** 8959 ** Changes can only be recorded for tables that have a PRIMARY KEY explicitly 8960 ** defined as part of their CREATE TABLE statement. It does not matter if the 8961 ** PRIMARY KEY is an "INTEGER PRIMARY KEY" (rowid alias) or not. The PRIMARY 8962 ** KEY may consist of a single column, or may be a composite key. 8963 ** 8964 ** It is not an error if the named table does not exist in the database. Nor 8965 ** is it an error if the named table does not have a PRIMARY KEY. However, 8966 ** no changes will be recorded in either of these scenarios. 8967 ** 8968 ** Changes are not recorded for individual rows that have NULL values stored 8969 ** in one or more of their PRIMARY KEY columns. 8970 ** 8971 ** SQLITE_OK is returned if the call completes without error. Or, if an error 8972 ** occurs, an SQLite error code (e.g. SQLITE_NOMEM) is returned. 8973 */ 8974 SQLITE_API int sqlite3session_attach( 8975 sqlite3_session *pSession, /* Session object */ 8976 const char *zTab /* Table name */ 8977 ); 8978 8979 /* 8980 ** CAPI3REF: Set a table filter on a Session Object. 8981 ** 8982 ** The second argument (xFilter) is the "filter callback". For changes to rows 8983 ** in tables that are not attached to the Session object, the filter is called 8984 ** to determine whether changes to the table's rows should be tracked or not. 8985 ** If xFilter returns 0, changes is not tracked. Note that once a table is 8986 ** attached, xFilter will not be called again. 8987 */ 8988 SQLITE_API void sqlite3session_table_filter( 8989 sqlite3_session *pSession, /* Session object */ 8990 int(*xFilter)( 8991 void *pCtx, /* Copy of third arg to _filter_table() */ 8992 const char *zTab /* Table name */ 8993 ), 8994 void *pCtx /* First argument passed to xFilter */ 8995 ); 8996 8997 /* 8998 ** CAPI3REF: Generate A Changeset From A Session Object 8999 ** 9000 ** Obtain a changeset containing changes to the tables attached to the 9001 ** session object passed as the first argument. If successful, 9002 ** set *ppChangeset to point to a buffer containing the changeset 9003 ** and *pnChangeset to the size of the changeset in bytes before returning 9004 ** SQLITE_OK. If an error occurs, set both *ppChangeset and *pnChangeset to 9005 ** zero and return an SQLite error code. 9006 ** 9007 ** A changeset consists of zero or more INSERT, UPDATE and/or DELETE changes, 9008 ** each representing a change to a single row of an attached table. An INSERT 9009 ** change contains the values of each field of a new database row. A DELETE 9010 ** contains the original values of each field of a deleted database row. An 9011 ** UPDATE change contains the original values of each field of an updated 9012 ** database row along with the updated values for each updated non-primary-key 9013 ** column. It is not possible for an UPDATE change to represent a change that 9014 ** modifies the values of primary key columns. If such a change is made, it 9015 ** is represented in a changeset as a DELETE followed by an INSERT. 9016 ** 9017 ** Changes are not recorded for rows that have NULL values stored in one or 9018 ** more of their PRIMARY KEY columns. If such a row is inserted or deleted, 9019 ** no corresponding change is present in the changesets returned by this 9020 ** function. If an existing row with one or more NULL values stored in 9021 ** PRIMARY KEY columns is updated so that all PRIMARY KEY columns are non-NULL, 9022 ** only an INSERT is appears in the changeset. Similarly, if an existing row 9023 ** with non-NULL PRIMARY KEY values is updated so that one or more of its 9024 ** PRIMARY KEY columns are set to NULL, the resulting changeset contains a 9025 ** DELETE change only. 9026 ** 9027 ** The contents of a changeset may be traversed using an iterator created 9028 ** using the [sqlite3changeset_start()] API. A changeset may be applied to 9029 ** a database with a compatible schema using the [sqlite3changeset_apply()] 9030 ** API. 9031 ** 9032 ** Within a changeset generated by this function, all changes related to a 9033 ** single table are grouped together. In other words, when iterating through 9034 ** a changeset or when applying a changeset to a database, all changes related 9035 ** to a single table are processed before moving on to the next table. Tables 9036 ** are sorted in the same order in which they were attached (or auto-attached) 9037 ** to the sqlite3_session object. The order in which the changes related to 9038 ** a single table are stored is undefined. 9039 ** 9040 ** Following a successful call to this function, it is the responsibility of 9041 ** the caller to eventually free the buffer that *ppChangeset points to using 9042 ** [sqlite3_free()]. 9043 ** 9044 ** <h3>Changeset Generation</h3> 9045 ** 9046 ** Once a table has been attached to a session object, the session object 9047 ** records the primary key values of all new rows inserted into the table. 9048 ** It also records the original primary key and other column values of any 9049 ** deleted or updated rows. For each unique primary key value, data is only 9050 ** recorded once - the first time a row with said primary key is inserted, 9051 ** updated or deleted in the lifetime of the session. 9052 ** 9053 ** There is one exception to the previous paragraph: when a row is inserted, 9054 ** updated or deleted, if one or more of its primary key columns contain a 9055 ** NULL value, no record of the change is made. 9056 ** 9057 ** The session object therefore accumulates two types of records - those 9058 ** that consist of primary key values only (created when the user inserts 9059 ** a new record) and those that consist of the primary key values and the 9060 ** original values of other table columns (created when the users deletes 9061 ** or updates a record). 9062 ** 9063 ** When this function is called, the requested changeset is created using 9064 ** both the accumulated records and the current contents of the database 9065 ** file. Specifically: 9066 ** 9067 ** <ul> 9068 ** <li> For each record generated by an insert, the database is queried 9069 ** for a row with a matching primary key. If one is found, an INSERT 9070 ** change is added to the changeset. If no such row is found, no change 9071 ** is added to the changeset. 9072 ** 9073 ** <li> For each record generated by an update or delete, the database is 9074 ** queried for a row with a matching primary key. If such a row is 9075 ** found and one or more of the non-primary key fields have been 9076 ** modified from their original values, an UPDATE change is added to 9077 ** the changeset. Or, if no such row is found in the table, a DELETE 9078 ** change is added to the changeset. If there is a row with a matching 9079 ** primary key in the database, but all fields contain their original 9080 ** values, no change is added to the changeset. 9081 ** </ul> 9082 ** 9083 ** This means, amongst other things, that if a row is inserted and then later 9084 ** deleted while a session object is active, neither the insert nor the delete 9085 ** will be present in the changeset. Or if a row is deleted and then later a 9086 ** row with the same primary key values inserted while a session object is 9087 ** active, the resulting changeset will contain an UPDATE change instead of 9088 ** a DELETE and an INSERT. 9089 ** 9090 ** When a session object is disabled (see the [sqlite3session_enable()] API), 9091 ** it does not accumulate records when rows are inserted, updated or deleted. 9092 ** This may appear to have some counter-intuitive effects if a single row 9093 ** is written to more than once during a session. For example, if a row 9094 ** is inserted while a session object is enabled, then later deleted while 9095 ** the same session object is disabled, no INSERT record will appear in the 9096 ** changeset, even though the delete took place while the session was disabled. 9097 ** Or, if one field of a row is updated while a session is disabled, and 9098 ** another field of the same row is updated while the session is enabled, the 9099 ** resulting changeset will contain an UPDATE change that updates both fields. 9100 */ 9101 SQLITE_API int sqlite3session_changeset( 9102 sqlite3_session *pSession, /* Session object */ 9103 int *pnChangeset, /* OUT: Size of buffer at *ppChangeset */ 9104 void **ppChangeset /* OUT: Buffer containing changeset */ 9105 ); 9106 9107 /* 9108 ** CAPI3REF: Load The Difference Between Tables Into A Session 9109 ** 9110 ** If it is not already attached to the session object passed as the first 9111 ** argument, this function attaches table zTbl in the same manner as the 9112 ** [sqlite3session_attach()] function. If zTbl does not exist, or if it 9113 ** does not have a primary key, this function is a no-op (but does not return 9114 ** an error). 9115 ** 9116 ** Argument zFromDb must be the name of a database ("main", "temp" etc.) 9117 ** attached to the same database handle as the session object that contains 9118 ** a table compatible with the table attached to the session by this function. 9119 ** A table is considered compatible if it: 9120 ** 9121 ** <ul> 9122 ** <li> Has the same name, 9123 ** <li> Has the same set of columns declared in the same order, and 9124 ** <li> Has the same PRIMARY KEY definition. 9125 ** </ul> 9126 ** 9127 ** If the tables are not compatible, SQLITE_SCHEMA is returned. If the tables 9128 ** are compatible but do not have any PRIMARY KEY columns, it is not an error 9129 ** but no changes are added to the session object. As with other session 9130 ** APIs, tables without PRIMARY KEYs are simply ignored. 9131 ** 9132 ** This function adds a set of changes to the session object that could be 9133 ** used to update the table in database zFrom (call this the "from-table") 9134 ** so that its content is the same as the table attached to the session 9135 ** object (call this the "to-table"). Specifically: 9136 ** 9137 ** <ul> 9138 ** <li> For each row (primary key) that exists in the to-table but not in 9139 ** the from-table, an INSERT record is added to the session object. 9140 ** 9141 ** <li> For each row (primary key) that exists in the to-table but not in 9142 ** the from-table, a DELETE record is added to the session object. 9143 ** 9144 ** <li> For each row (primary key) that exists in both tables, but features 9145 ** different non-PK values in each, an UPDATE record is added to the 9146 ** session. 9147 ** </ul> 9148 ** 9149 ** To clarify, if this function is called and then a changeset constructed 9150 ** using [sqlite3session_changeset()], then after applying that changeset to 9151 ** database zFrom the contents of the two compatible tables would be 9152 ** identical. 9153 ** 9154 ** It an error if database zFrom does not exist or does not contain the 9155 ** required compatible table. 9156 ** 9157 ** If the operation successful, SQLITE_OK is returned. Otherwise, an SQLite 9158 ** error code. In this case, if argument pzErrMsg is not NULL, *pzErrMsg 9159 ** may be set to point to a buffer containing an English language error 9160 ** message. It is the responsibility of the caller to free this buffer using 9161 ** sqlite3_free(). 9162 */ 9163 SQLITE_API int sqlite3session_diff( 9164 sqlite3_session *pSession, 9165 const char *zFromDb, 9166 const char *zTbl, 9167 char **pzErrMsg 9168 ); 9169 9170 9171 /* 9172 ** CAPI3REF: Generate A Patchset From A Session Object 9173 ** 9174 ** The differences between a patchset and a changeset are that: 9175 ** 9176 ** <ul> 9177 ** <li> DELETE records consist of the primary key fields only. The 9178 ** original values of other fields are omitted. 9179 ** <li> The original values of any modified fields are omitted from 9180 ** UPDATE records. 9181 ** </ul> 9182 ** 9183 ** A patchset blob may be used with up to date versions of all 9184 ** sqlite3changeset_xxx API functions except for sqlite3changeset_invert(), 9185 ** which returns SQLITE_CORRUPT if it is passed a patchset. Similarly, 9186 ** attempting to use a patchset blob with old versions of the 9187 ** sqlite3changeset_xxx APIs also provokes an SQLITE_CORRUPT error. 9188 ** 9189 ** Because the non-primary key "old.*" fields are omitted, no 9190 ** SQLITE_CHANGESET_DATA conflicts can be detected or reported if a patchset 9191 ** is passed to the sqlite3changeset_apply() API. Other conflict types work 9192 ** in the same way as for changesets. 9193 ** 9194 ** Changes within a patchset are ordered in the same way as for changesets 9195 ** generated by the sqlite3session_changeset() function (i.e. all changes for 9196 ** a single table are grouped together, tables appear in the order in which 9197 ** they were attached to the session object). 9198 */ 9199 SQLITE_API int sqlite3session_patchset( 9200 sqlite3_session *pSession, /* Session object */ 9201 int *pnPatchset, /* OUT: Size of buffer at *ppChangeset */ 9202 void **ppPatchset /* OUT: Buffer containing changeset */ 9203 ); 9204 9205 /* 9206 ** CAPI3REF: Test if a changeset has recorded any changes. 9207 ** 9208 ** Return non-zero if no changes to attached tables have been recorded by 9209 ** the session object passed as the first argument. Otherwise, if one or 9210 ** more changes have been recorded, return zero. 9211 ** 9212 ** Even if this function returns zero, it is possible that calling 9213 ** [sqlite3session_changeset()] on the session handle may still return a 9214 ** changeset that contains no changes. This can happen when a row in 9215 ** an attached table is modified and then later on the original values 9216 ** are restored. However, if this function returns non-zero, then it is 9217 ** guaranteed that a call to sqlite3session_changeset() will return a 9218 ** changeset containing zero changes. 9219 */ 9220 SQLITE_API int sqlite3session_isempty(sqlite3_session *pSession); 9221 9222 /* 9223 ** CAPI3REF: Create An Iterator To Traverse A Changeset 9224 ** 9225 ** Create an iterator used to iterate through the contents of a changeset. 9226 ** If successful, *pp is set to point to the iterator handle and SQLITE_OK 9227 ** is returned. Otherwise, if an error occurs, *pp is set to zero and an 9228 ** SQLite error code is returned. 9229 ** 9230 ** The following functions can be used to advance and query a changeset 9231 ** iterator created by this function: 9232 ** 9233 ** <ul> 9234 ** <li> [sqlite3changeset_next()] 9235 ** <li> [sqlite3changeset_op()] 9236 ** <li> [sqlite3changeset_new()] 9237 ** <li> [sqlite3changeset_old()] 9238 ** </ul> 9239 ** 9240 ** It is the responsibility of the caller to eventually destroy the iterator 9241 ** by passing it to [sqlite3changeset_finalize()]. The buffer containing the 9242 ** changeset (pChangeset) must remain valid until after the iterator is 9243 ** destroyed. 9244 ** 9245 ** Assuming the changeset blob was created by one of the 9246 ** [sqlite3session_changeset()], [sqlite3changeset_concat()] or 9247 ** [sqlite3changeset_invert()] functions, all changes within the changeset 9248 ** that apply to a single table are grouped together. This means that when 9249 ** an application iterates through a changeset using an iterator created by 9250 ** this function, all changes that relate to a single table are visited 9251 ** consecutively. There is no chance that the iterator will visit a change 9252 ** the applies to table X, then one for table Y, and then later on visit 9253 ** another change for table X. 9254 */ 9255 SQLITE_API int sqlite3changeset_start( 9256 sqlite3_changeset_iter **pp, /* OUT: New changeset iterator handle */ 9257 int nChangeset, /* Size of changeset blob in bytes */ 9258 void *pChangeset /* Pointer to blob containing changeset */ 9259 ); 9260 9261 9262 /* 9263 ** CAPI3REF: Advance A Changeset Iterator 9264 ** 9265 ** This function may only be used with iterators created by function 9266 ** [sqlite3changeset_start()]. If it is called on an iterator passed to 9267 ** a conflict-handler callback by [sqlite3changeset_apply()], SQLITE_MISUSE 9268 ** is returned and the call has no effect. 9269 ** 9270 ** Immediately after an iterator is created by sqlite3changeset_start(), it 9271 ** does not point to any change in the changeset. Assuming the changeset 9272 ** is not empty, the first call to this function advances the iterator to 9273 ** point to the first change in the changeset. Each subsequent call advances 9274 ** the iterator to point to the next change in the changeset (if any). If 9275 ** no error occurs and the iterator points to a valid change after a call 9276 ** to sqlite3changeset_next() has advanced it, SQLITE_ROW is returned. 9277 ** Otherwise, if all changes in the changeset have already been visited, 9278 ** SQLITE_DONE is returned. 9279 ** 9280 ** If an error occurs, an SQLite error code is returned. Possible error 9281 ** codes include SQLITE_CORRUPT (if the changeset buffer is corrupt) or 9282 ** SQLITE_NOMEM. 9283 */ 9284 SQLITE_API int sqlite3changeset_next(sqlite3_changeset_iter *pIter); 9285 9286 /* 9287 ** CAPI3REF: Obtain The Current Operation From A Changeset Iterator 9288 ** 9289 ** The pIter argument passed to this function may either be an iterator 9290 ** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator 9291 ** created by [sqlite3changeset_start()]. In the latter case, the most recent 9292 ** call to [sqlite3changeset_next()] must have returned [SQLITE_ROW]. If this 9293 ** is not the case, this function returns [SQLITE_MISUSE]. 9294 ** 9295 ** If argument pzTab is not NULL, then *pzTab is set to point to a 9296 ** nul-terminated utf-8 encoded string containing the name of the table 9297 ** affected by the current change. The buffer remains valid until either 9298 ** sqlite3changeset_next() is called on the iterator or until the 9299 ** conflict-handler function returns. If pnCol is not NULL, then *pnCol is 9300 ** set to the number of columns in the table affected by the change. If 9301 ** pbIncorrect is not NULL, then *pbIndirect is set to true (1) if the change 9302 ** is an indirect change, or false (0) otherwise. See the documentation for 9303 ** [sqlite3session_indirect()] for a description of direct and indirect 9304 ** changes. Finally, if pOp is not NULL, then *pOp is set to one of 9305 ** [SQLITE_INSERT], [SQLITE_DELETE] or [SQLITE_UPDATE], depending on the 9306 ** type of change that the iterator currently points to. 9307 ** 9308 ** If no error occurs, SQLITE_OK is returned. If an error does occur, an 9309 ** SQLite error code is returned. The values of the output variables may not 9310 ** be trusted in this case. 9311 */ 9312 SQLITE_API int sqlite3changeset_op( 9313 sqlite3_changeset_iter *pIter, /* Iterator object */ 9314 const char **pzTab, /* OUT: Pointer to table name */ 9315 int *pnCol, /* OUT: Number of columns in table */ 9316 int *pOp, /* OUT: SQLITE_INSERT, DELETE or UPDATE */ 9317 int *pbIndirect /* OUT: True for an 'indirect' change */ 9318 ); 9319 9320 /* 9321 ** CAPI3REF: Obtain The Primary Key Definition Of A Table 9322 ** 9323 ** For each modified table, a changeset includes the following: 9324 ** 9325 ** <ul> 9326 ** <li> The number of columns in the table, and 9327 ** <li> Which of those columns make up the tables PRIMARY KEY. 9328 ** </ul> 9329 ** 9330 ** This function is used to find which columns comprise the PRIMARY KEY of 9331 ** the table modified by the change that iterator pIter currently points to. 9332 ** If successful, *pabPK is set to point to an array of nCol entries, where 9333 ** nCol is the number of columns in the table. Elements of *pabPK are set to 9334 ** 0x01 if the corresponding column is part of the tables primary key, or 9335 ** 0x00 if it is not. 9336 ** 9337 ** If argument pnCol is not NULL, then *pnCol is set to the number of columns 9338 ** in the table. 9339 ** 9340 ** If this function is called when the iterator does not point to a valid 9341 ** entry, SQLITE_MISUSE is returned and the output variables zeroed. Otherwise, 9342 ** SQLITE_OK is returned and the output variables populated as described 9343 ** above. 9344 */ 9345 SQLITE_API int sqlite3changeset_pk( 9346 sqlite3_changeset_iter *pIter, /* Iterator object */ 9347 unsigned char **pabPK, /* OUT: Array of boolean - true for PK cols */ 9348 int *pnCol /* OUT: Number of entries in output array */ 9349 ); 9350 9351 /* 9352 ** CAPI3REF: Obtain old.* Values From A Changeset Iterator 9353 ** 9354 ** The pIter argument passed to this function may either be an iterator 9355 ** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator 9356 ** created by [sqlite3changeset_start()]. In the latter case, the most recent 9357 ** call to [sqlite3changeset_next()] must have returned SQLITE_ROW. 9358 ** Furthermore, it may only be called if the type of change that the iterator 9359 ** currently points to is either [SQLITE_DELETE] or [SQLITE_UPDATE]. Otherwise, 9360 ** this function returns [SQLITE_MISUSE] and sets *ppValue to NULL. 9361 ** 9362 ** Argument iVal must be greater than or equal to 0, and less than the number 9363 ** of columns in the table affected by the current change. Otherwise, 9364 ** [SQLITE_RANGE] is returned and *ppValue is set to NULL. 9365 ** 9366 ** If successful, this function sets *ppValue to point to a protected 9367 ** sqlite3_value object containing the iVal'th value from the vector of 9368 ** original row values stored as part of the UPDATE or DELETE change and 9369 ** returns SQLITE_OK. The name of the function comes from the fact that this 9370 ** is similar to the "old.*" columns available to update or delete triggers. 9371 ** 9372 ** If some other error occurs (e.g. an OOM condition), an SQLite error code 9373 ** is returned and *ppValue is set to NULL. 9374 */ 9375 SQLITE_API int sqlite3changeset_old( 9376 sqlite3_changeset_iter *pIter, /* Changeset iterator */ 9377 int iVal, /* Column number */ 9378 sqlite3_value **ppValue /* OUT: Old value (or NULL pointer) */ 9379 ); 9380 9381 /* 9382 ** CAPI3REF: Obtain new.* Values From A Changeset Iterator 9383 ** 9384 ** The pIter argument passed to this function may either be an iterator 9385 ** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator 9386 ** created by [sqlite3changeset_start()]. In the latter case, the most recent 9387 ** call to [sqlite3changeset_next()] must have returned SQLITE_ROW. 9388 ** Furthermore, it may only be called if the type of change that the iterator 9389 ** currently points to is either [SQLITE_UPDATE] or [SQLITE_INSERT]. Otherwise, 9390 ** this function returns [SQLITE_MISUSE] and sets *ppValue to NULL. 9391 ** 9392 ** Argument iVal must be greater than or equal to 0, and less than the number 9393 ** of columns in the table affected by the current change. Otherwise, 9394 ** [SQLITE_RANGE] is returned and *ppValue is set to NULL. 9395 ** 9396 ** If successful, this function sets *ppValue to point to a protected 9397 ** sqlite3_value object containing the iVal'th value from the vector of 9398 ** new row values stored as part of the UPDATE or INSERT change and 9399 ** returns SQLITE_OK. If the change is an UPDATE and does not include 9400 ** a new value for the requested column, *ppValue is set to NULL and 9401 ** SQLITE_OK returned. The name of the function comes from the fact that 9402 ** this is similar to the "new.*" columns available to update or delete 9403 ** triggers. 9404 ** 9405 ** If some other error occurs (e.g. an OOM condition), an SQLite error code 9406 ** is returned and *ppValue is set to NULL. 9407 */ 9408 SQLITE_API int sqlite3changeset_new( 9409 sqlite3_changeset_iter *pIter, /* Changeset iterator */ 9410 int iVal, /* Column number */ 9411 sqlite3_value **ppValue /* OUT: New value (or NULL pointer) */ 9412 ); 9413 9414 /* 9415 ** CAPI3REF: Obtain Conflicting Row Values From A Changeset Iterator 9416 ** 9417 ** This function should only be used with iterator objects passed to a 9418 ** conflict-handler callback by [sqlite3changeset_apply()] with either 9419 ** [SQLITE_CHANGESET_DATA] or [SQLITE_CHANGESET_CONFLICT]. If this function 9420 ** is called on any other iterator, [SQLITE_MISUSE] is returned and *ppValue 9421 ** is set to NULL. 9422 ** 9423 ** Argument iVal must be greater than or equal to 0, and less than the number 9424 ** of columns in the table affected by the current change. Otherwise, 9425 ** [SQLITE_RANGE] is returned and *ppValue is set to NULL. 9426 ** 9427 ** If successful, this function sets *ppValue to point to a protected 9428 ** sqlite3_value object containing the iVal'th value from the 9429 ** "conflicting row" associated with the current conflict-handler callback 9430 ** and returns SQLITE_OK. 9431 ** 9432 ** If some other error occurs (e.g. an OOM condition), an SQLite error code 9433 ** is returned and *ppValue is set to NULL. 9434 */ 9435 SQLITE_API int sqlite3changeset_conflict( 9436 sqlite3_changeset_iter *pIter, /* Changeset iterator */ 9437 int iVal, /* Column number */ 9438 sqlite3_value **ppValue /* OUT: Value from conflicting row */ 9439 ); 9440 9441 /* 9442 ** CAPI3REF: Determine The Number Of Foreign Key Constraint Violations 9443 ** 9444 ** This function may only be called with an iterator passed to an 9445 ** SQLITE_CHANGESET_FOREIGN_KEY conflict handler callback. In this case 9446 ** it sets the output variable to the total number of known foreign key 9447 ** violations in the destination database and returns SQLITE_OK. 9448 ** 9449 ** In all other cases this function returns SQLITE_MISUSE. 9450 */ 9451 SQLITE_API int sqlite3changeset_fk_conflicts( 9452 sqlite3_changeset_iter *pIter, /* Changeset iterator */ 9453 int *pnOut /* OUT: Number of FK violations */ 9454 ); 9455 9456 9457 /* 9458 ** CAPI3REF: Finalize A Changeset Iterator 9459 ** 9460 ** This function is used to finalize an iterator allocated with 9461 ** [sqlite3changeset_start()]. 9462 ** 9463 ** This function should only be called on iterators created using the 9464 ** [sqlite3changeset_start()] function. If an application calls this 9465 ** function with an iterator passed to a conflict-handler by 9466 ** [sqlite3changeset_apply()], [SQLITE_MISUSE] is immediately returned and the 9467 ** call has no effect. 9468 ** 9469 ** If an error was encountered within a call to an sqlite3changeset_xxx() 9470 ** function (for example an [SQLITE_CORRUPT] in [sqlite3changeset_next()] or an 9471 ** [SQLITE_NOMEM] in [sqlite3changeset_new()]) then an error code corresponding 9472 ** to that error is returned by this function. Otherwise, SQLITE_OK is 9473 ** returned. This is to allow the following pattern (pseudo-code): 9474 ** 9475 ** sqlite3changeset_start(); 9476 ** while( SQLITE_ROW==sqlite3changeset_next() ){ 9477 ** // Do something with change. 9478 ** } 9479 ** rc = sqlite3changeset_finalize(); 9480 ** if( rc!=SQLITE_OK ){ 9481 ** // An error has occurred 9482 ** } 9483 */ 9484 SQLITE_API int sqlite3changeset_finalize(sqlite3_changeset_iter *pIter); 9485 9486 /* 9487 ** CAPI3REF: Invert A Changeset 9488 ** 9489 ** This function is used to "invert" a changeset object. Applying an inverted 9490 ** changeset to a database reverses the effects of applying the uninverted 9491 ** changeset. Specifically: 9492 ** 9493 ** <ul> 9494 ** <li> Each DELETE change is changed to an INSERT, and 9495 ** <li> Each INSERT change is changed to a DELETE, and 9496 ** <li> For each UPDATE change, the old.* and new.* values are exchanged. 9497 ** </ul> 9498 ** 9499 ** This function does not change the order in which changes appear within 9500 ** the changeset. It merely reverses the sense of each individual change. 9501 ** 9502 ** If successful, a pointer to a buffer containing the inverted changeset 9503 ** is stored in *ppOut, the size of the same buffer is stored in *pnOut, and 9504 ** SQLITE_OK is returned. If an error occurs, both *pnOut and *ppOut are 9505 ** zeroed and an SQLite error code returned. 9506 ** 9507 ** It is the responsibility of the caller to eventually call sqlite3_free() 9508 ** on the *ppOut pointer to free the buffer allocation following a successful 9509 ** call to this function. 9510 ** 9511 ** WARNING/TODO: This function currently assumes that the input is a valid 9512 ** changeset. If it is not, the results are undefined. 9513 */ 9514 SQLITE_API int sqlite3changeset_invert( 9515 int nIn, const void *pIn, /* Input changeset */ 9516 int *pnOut, void **ppOut /* OUT: Inverse of input */ 9517 ); 9518 9519 /* 9520 ** CAPI3REF: Concatenate Two Changeset Objects 9521 ** 9522 ** This function is used to concatenate two changesets, A and B, into a 9523 ** single changeset. The result is a changeset equivalent to applying 9524 ** changeset A followed by changeset B. 9525 ** 9526 ** This function combines the two input changesets using an 9527 ** sqlite3_changegroup object. Calling it produces similar results as the 9528 ** following code fragment: 9529 ** 9530 ** sqlite3_changegroup *pGrp; 9531 ** rc = sqlite3_changegroup_new(&pGrp); 9532 ** if( rc==SQLITE_OK ) rc = sqlite3changegroup_add(pGrp, nA, pA); 9533 ** if( rc==SQLITE_OK ) rc = sqlite3changegroup_add(pGrp, nB, pB); 9534 ** if( rc==SQLITE_OK ){ 9535 ** rc = sqlite3changegroup_output(pGrp, pnOut, ppOut); 9536 ** }else{ 9537 ** *ppOut = 0; 9538 ** *pnOut = 0; 9539 ** } 9540 ** 9541 ** Refer to the sqlite3_changegroup documentation below for details. 9542 */ 9543 SQLITE_API int sqlite3changeset_concat( 9544 int nA, /* Number of bytes in buffer pA */ 9545 void *pA, /* Pointer to buffer containing changeset A */ 9546 int nB, /* Number of bytes in buffer pB */ 9547 void *pB, /* Pointer to buffer containing changeset B */ 9548 int *pnOut, /* OUT: Number of bytes in output changeset */ 9549 void **ppOut /* OUT: Buffer containing output changeset */ 9550 ); 9551 9552 9553 /* 9554 ** CAPI3REF: Changegroup Handle 9555 */ 9556 typedef struct sqlite3_changegroup sqlite3_changegroup; 9557 9558 /* 9559 ** CAPI3REF: Create A New Changegroup Object 9560 ** 9561 ** An sqlite3_changegroup object is used to combine two or more changesets 9562 ** (or patchsets) into a single changeset (or patchset). A single changegroup 9563 ** object may combine changesets or patchsets, but not both. The output is 9564 ** always in the same format as the input. 9565 ** 9566 ** If successful, this function returns SQLITE_OK and populates (*pp) with 9567 ** a pointer to a new sqlite3_changegroup object before returning. The caller 9568 ** should eventually free the returned object using a call to 9569 ** sqlite3changegroup_delete(). If an error occurs, an SQLite error code 9570 ** (i.e. SQLITE_NOMEM) is returned and *pp is set to NULL. 9571 ** 9572 ** The usual usage pattern for an sqlite3_changegroup object is as follows: 9573 ** 9574 ** <ul> 9575 ** <li> It is created using a call to sqlite3changegroup_new(). 9576 ** 9577 ** <li> Zero or more changesets (or patchsets) are added to the object 9578 ** by calling sqlite3changegroup_add(). 9579 ** 9580 ** <li> The result of combining all input changesets together is obtained 9581 ** by the application via a call to sqlite3changegroup_output(). 9582 ** 9583 ** <li> The object is deleted using a call to sqlite3changegroup_delete(). 9584 ** </ul> 9585 ** 9586 ** Any number of calls to add() and output() may be made between the calls to 9587 ** new() and delete(), and in any order. 9588 ** 9589 ** As well as the regular sqlite3changegroup_add() and 9590 ** sqlite3changegroup_output() functions, also available are the streaming 9591 ** versions sqlite3changegroup_add_strm() and sqlite3changegroup_output_strm(). 9592 */ 9593 SQLITE_API int sqlite3changegroup_new(sqlite3_changegroup **pp); 9594 9595 /* 9596 ** CAPI3REF: Add A Changeset To A Changegroup 9597 ** 9598 ** Add all changes within the changeset (or patchset) in buffer pData (size 9599 ** nData bytes) to the changegroup. 9600 ** 9601 ** If the buffer contains a patchset, then all prior calls to this function 9602 ** on the same changegroup object must also have specified patchsets. Or, if 9603 ** the buffer contains a changeset, so must have the earlier calls to this 9604 ** function. Otherwise, SQLITE_ERROR is returned and no changes are added 9605 ** to the changegroup. 9606 ** 9607 ** Rows within the changeset and changegroup are identified by the values in 9608 ** their PRIMARY KEY columns. A change in the changeset is considered to 9609 ** apply to the same row as a change already present in the changegroup if 9610 ** the two rows have the same primary key. 9611 ** 9612 ** Changes to rows that do not already appear in the changegroup are 9613 ** simply copied into it. Or, if both the new changeset and the changegroup 9614 ** contain changes that apply to a single row, the final contents of the 9615 ** changegroup depends on the type of each change, as follows: 9616 ** 9617 ** <table border=1 style="margin-left:8ex;margin-right:8ex"> 9618 ** <tr><th style="white-space:pre">Existing Change </th> 9619 ** <th style="white-space:pre">New Change </th> 9620 ** <th>Output Change 9621 ** <tr><td>INSERT <td>INSERT <td> 9622 ** The new change is ignored. This case does not occur if the new 9623 ** changeset was recorded immediately after the changesets already 9624 ** added to the changegroup. 9625 ** <tr><td>INSERT <td>UPDATE <td> 9626 ** The INSERT change remains in the changegroup. The values in the 9627 ** INSERT change are modified as if the row was inserted by the 9628 ** existing change and then updated according to the new change. 9629 ** <tr><td>INSERT <td>DELETE <td> 9630 ** The existing INSERT is removed from the changegroup. The DELETE is 9631 ** not added. 9632 ** <tr><td>UPDATE <td>INSERT <td> 9633 ** The new change is ignored. This case does not occur if the new 9634 ** changeset was recorded immediately after the changesets already 9635 ** added to the changegroup. 9636 ** <tr><td>UPDATE <td>UPDATE <td> 9637 ** The existing UPDATE remains within the changegroup. It is amended 9638 ** so that the accompanying values are as if the row was updated once 9639 ** by the existing change and then again by the new change. 9640 ** <tr><td>UPDATE <td>DELETE <td> 9641 ** The existing UPDATE is replaced by the new DELETE within the 9642 ** changegroup. 9643 ** <tr><td>DELETE <td>INSERT <td> 9644 ** If one or more of the column values in the row inserted by the 9645 ** new change differ from those in the row deleted by the existing 9646 ** change, the existing DELETE is replaced by an UPDATE within the 9647 ** changegroup. Otherwise, if the inserted row is exactly the same 9648 ** as the deleted row, the existing DELETE is simply discarded. 9649 ** <tr><td>DELETE <td>UPDATE <td> 9650 ** The new change is ignored. This case does not occur if the new 9651 ** changeset was recorded immediately after the changesets already 9652 ** added to the changegroup. 9653 ** <tr><td>DELETE <td>DELETE <td> 9654 ** The new change is ignored. This case does not occur if the new 9655 ** changeset was recorded immediately after the changesets already 9656 ** added to the changegroup. 9657 ** </table> 9658 ** 9659 ** If the new changeset contains changes to a table that is already present 9660 ** in the changegroup, then the number of columns and the position of the 9661 ** primary key columns for the table must be consistent. If this is not the 9662 ** case, this function fails with SQLITE_SCHEMA. If the input changeset 9663 ** appears to be corrupt and the corruption is detected, SQLITE_CORRUPT is 9664 ** returned. Or, if an out-of-memory condition occurs during processing, this 9665 ** function returns SQLITE_NOMEM. In all cases, if an error occurs the 9666 ** final contents of the changegroup is undefined. 9667 ** 9668 ** If no error occurs, SQLITE_OK is returned. 9669 */ 9670 SQLITE_API int sqlite3changegroup_add(sqlite3_changegroup*, int nData, void *pData); 9671 9672 /* 9673 ** CAPI3REF: Obtain A Composite Changeset From A Changegroup 9674 ** 9675 ** Obtain a buffer containing a changeset (or patchset) representing the 9676 ** current contents of the changegroup. If the inputs to the changegroup 9677 ** were themselves changesets, the output is a changeset. Or, if the 9678 ** inputs were patchsets, the output is also a patchset. 9679 ** 9680 ** As with the output of the sqlite3session_changeset() and 9681 ** sqlite3session_patchset() functions, all changes related to a single 9682 ** table are grouped together in the output of this function. Tables appear 9683 ** in the same order as for the very first changeset added to the changegroup. 9684 ** If the second or subsequent changesets added to the changegroup contain 9685 ** changes for tables that do not appear in the first changeset, they are 9686 ** appended onto the end of the output changeset, again in the order in 9687 ** which they are first encountered. 9688 ** 9689 ** If an error occurs, an SQLite error code is returned and the output 9690 ** variables (*pnData) and (*ppData) are set to 0. Otherwise, SQLITE_OK 9691 ** is returned and the output variables are set to the size of and a 9692 ** pointer to the output buffer, respectively. In this case it is the 9693 ** responsibility of the caller to eventually free the buffer using a 9694 ** call to sqlite3_free(). 9695 */ 9696 SQLITE_API int sqlite3changegroup_output( 9697 sqlite3_changegroup*, 9698 int *pnData, /* OUT: Size of output buffer in bytes */ 9699 void **ppData /* OUT: Pointer to output buffer */ 9700 ); 9701 9702 /* 9703 ** CAPI3REF: Delete A Changegroup Object 9704 */ 9705 SQLITE_API void sqlite3changegroup_delete(sqlite3_changegroup*); 9706 9707 /* 9708 ** CAPI3REF: Apply A Changeset To A Database 9709 ** 9710 ** Apply a changeset to a database. This function attempts to update the 9711 ** "main" database attached to handle db with the changes found in the 9712 ** changeset passed via the second and third arguments. 9713 ** 9714 ** The fourth argument (xFilter) passed to this function is the "filter 9715 ** callback". If it is not NULL, then for each table affected by at least one 9716 ** change in the changeset, the filter callback is invoked with 9717 ** the table name as the second argument, and a copy of the context pointer 9718 ** passed as the sixth argument to this function as the first. If the "filter 9719 ** callback" returns zero, then no attempt is made to apply any changes to 9720 ** the table. Otherwise, if the return value is non-zero or the xFilter 9721 ** argument to this function is NULL, all changes related to the table are 9722 ** attempted. 9723 ** 9724 ** For each table that is not excluded by the filter callback, this function 9725 ** tests that the target database contains a compatible table. A table is 9726 ** considered compatible if all of the following are true: 9727 ** 9728 ** <ul> 9729 ** <li> The table has the same name as the name recorded in the 9730 ** changeset, and 9731 ** <li> The table has at least as many columns as recorded in the 9732 ** changeset, and 9733 ** <li> The table has primary key columns in the same position as 9734 ** recorded in the changeset. 9735 ** </ul> 9736 ** 9737 ** If there is no compatible table, it is not an error, but none of the 9738 ** changes associated with the table are applied. A warning message is issued 9739 ** via the sqlite3_log() mechanism with the error code SQLITE_SCHEMA. At most 9740 ** one such warning is issued for each table in the changeset. 9741 ** 9742 ** For each change for which there is a compatible table, an attempt is made 9743 ** to modify the table contents according to the UPDATE, INSERT or DELETE 9744 ** change. If a change cannot be applied cleanly, the conflict handler 9745 ** function passed as the fifth argument to sqlite3changeset_apply() may be 9746 ** invoked. A description of exactly when the conflict handler is invoked for 9747 ** each type of change is below. 9748 ** 9749 ** Unlike the xFilter argument, xConflict may not be passed NULL. The results 9750 ** of passing anything other than a valid function pointer as the xConflict 9751 ** argument are undefined. 9752 ** 9753 ** Each time the conflict handler function is invoked, it must return one 9754 ** of [SQLITE_CHANGESET_OMIT], [SQLITE_CHANGESET_ABORT] or 9755 ** [SQLITE_CHANGESET_REPLACE]. SQLITE_CHANGESET_REPLACE may only be returned 9756 ** if the second argument passed to the conflict handler is either 9757 ** SQLITE_CHANGESET_DATA or SQLITE_CHANGESET_CONFLICT. If the conflict-handler 9758 ** returns an illegal value, any changes already made are rolled back and 9759 ** the call to sqlite3changeset_apply() returns SQLITE_MISUSE. Different 9760 ** actions are taken by sqlite3changeset_apply() depending on the value 9761 ** returned by each invocation of the conflict-handler function. Refer to 9762 ** the documentation for the three 9763 ** [SQLITE_CHANGESET_OMIT|available return values] for details. 9764 ** 9765 ** <dl> 9766 ** <dt>DELETE Changes<dd> 9767 ** For each DELETE change, this function checks if the target database 9768 ** contains a row with the same primary key value (or values) as the 9769 ** original row values stored in the changeset. If it does, and the values 9770 ** stored in all non-primary key columns also match the values stored in 9771 ** the changeset the row is deleted from the target database. 9772 ** 9773 ** If a row with matching primary key values is found, but one or more of 9774 ** the non-primary key fields contains a value different from the original 9775 ** row value stored in the changeset, the conflict-handler function is 9776 ** invoked with [SQLITE_CHANGESET_DATA] as the second argument. If the 9777 ** database table has more columns than are recorded in the changeset, 9778 ** only the values of those non-primary key fields are compared against 9779 ** the current database contents - any trailing database table columns 9780 ** are ignored. 9781 ** 9782 ** If no row with matching primary key values is found in the database, 9783 ** the conflict-handler function is invoked with [SQLITE_CHANGESET_NOTFOUND] 9784 ** passed as the second argument. 9785 ** 9786 ** If the DELETE operation is attempted, but SQLite returns SQLITE_CONSTRAINT 9787 ** (which can only happen if a foreign key constraint is violated), the 9788 ** conflict-handler function is invoked with [SQLITE_CHANGESET_CONSTRAINT] 9789 ** passed as the second argument. This includes the case where the DELETE 9790 ** operation is attempted because an earlier call to the conflict handler 9791 ** function returned [SQLITE_CHANGESET_REPLACE]. 9792 ** 9793 ** <dt>INSERT Changes<dd> 9794 ** For each INSERT change, an attempt is made to insert the new row into 9795 ** the database. If the changeset row contains fewer fields than the 9796 ** database table, the trailing fields are populated with their default 9797 ** values. 9798 ** 9799 ** If the attempt to insert the row fails because the database already 9800 ** contains a row with the same primary key values, the conflict handler 9801 ** function is invoked with the second argument set to 9802 ** [SQLITE_CHANGESET_CONFLICT]. 9803 ** 9804 ** If the attempt to insert the row fails because of some other constraint 9805 ** violation (e.g. NOT NULL or UNIQUE), the conflict handler function is 9806 ** invoked with the second argument set to [SQLITE_CHANGESET_CONSTRAINT]. 9807 ** This includes the case where the INSERT operation is re-attempted because 9808 ** an earlier call to the conflict handler function returned 9809 ** [SQLITE_CHANGESET_REPLACE]. 9810 ** 9811 ** <dt>UPDATE Changes<dd> 9812 ** For each UPDATE change, this function checks if the target database 9813 ** contains a row with the same primary key value (or values) as the 9814 ** original row values stored in the changeset. If it does, and the values 9815 ** stored in all modified non-primary key columns also match the values 9816 ** stored in the changeset the row is updated within the target database. 9817 ** 9818 ** If a row with matching primary key values is found, but one or more of 9819 ** the modified non-primary key fields contains a value different from an 9820 ** original row value stored in the changeset, the conflict-handler function 9821 ** is invoked with [SQLITE_CHANGESET_DATA] as the second argument. Since 9822 ** UPDATE changes only contain values for non-primary key fields that are 9823 ** to be modified, only those fields need to match the original values to 9824 ** avoid the SQLITE_CHANGESET_DATA conflict-handler callback. 9825 ** 9826 ** If no row with matching primary key values is found in the database, 9827 ** the conflict-handler function is invoked with [SQLITE_CHANGESET_NOTFOUND] 9828 ** passed as the second argument. 9829 ** 9830 ** If the UPDATE operation is attempted, but SQLite returns 9831 ** SQLITE_CONSTRAINT, the conflict-handler function is invoked with 9832 ** [SQLITE_CHANGESET_CONSTRAINT] passed as the second argument. 9833 ** This includes the case where the UPDATE operation is attempted after 9834 ** an earlier call to the conflict handler function returned 9835 ** [SQLITE_CHANGESET_REPLACE]. 9836 ** </dl> 9837 ** 9838 ** It is safe to execute SQL statements, including those that write to the 9839 ** table that the callback related to, from within the xConflict callback. 9840 ** This can be used to further customize the applications conflict 9841 ** resolution strategy. 9842 ** 9843 ** All changes made by this function are enclosed in a savepoint transaction. 9844 ** If any other error (aside from a constraint failure when attempting to 9845 ** write to the target database) occurs, then the savepoint transaction is 9846 ** rolled back, restoring the target database to its original state, and an 9847 ** SQLite error code returned. 9848 */ 9849 SQLITE_API int sqlite3changeset_apply( 9850 sqlite3 *db, /* Apply change to "main" db of this handle */ 9851 int nChangeset, /* Size of changeset in bytes */ 9852 void *pChangeset, /* Changeset blob */ 9853 int(*xFilter)( 9854 void *pCtx, /* Copy of sixth arg to _apply() */ 9855 const char *zTab /* Table name */ 9856 ), 9857 int(*xConflict)( 9858 void *pCtx, /* Copy of sixth arg to _apply() */ 9859 int eConflict, /* DATA, MISSING, CONFLICT, CONSTRAINT */ 9860 sqlite3_changeset_iter *p /* Handle describing change and conflict */ 9861 ), 9862 void *pCtx /* First argument passed to xConflict */ 9863 ); 9864 9865 /* 9866 ** CAPI3REF: Constants Passed To The Conflict Handler 9867 ** 9868 ** Values that may be passed as the second argument to a conflict-handler. 9869 ** 9870 ** <dl> 9871 ** <dt>SQLITE_CHANGESET_DATA<dd> 9872 ** The conflict handler is invoked with CHANGESET_DATA as the second argument 9873 ** when processing a DELETE or UPDATE change if a row with the required 9874 ** PRIMARY KEY fields is present in the database, but one or more other 9875 ** (non primary-key) fields modified by the update do not contain the 9876 ** expected "before" values. 9877 ** 9878 ** The conflicting row, in this case, is the database row with the matching 9879 ** primary key. 9880 ** 9881 ** <dt>SQLITE_CHANGESET_NOTFOUND<dd> 9882 ** The conflict handler is invoked with CHANGESET_NOTFOUND as the second 9883 ** argument when processing a DELETE or UPDATE change if a row with the 9884 ** required PRIMARY KEY fields is not present in the database. 9885 ** 9886 ** There is no conflicting row in this case. The results of invoking the 9887 ** sqlite3changeset_conflict() API are undefined. 9888 ** 9889 ** <dt>SQLITE_CHANGESET_CONFLICT<dd> 9890 ** CHANGESET_CONFLICT is passed as the second argument to the conflict 9891 ** handler while processing an INSERT change if the operation would result 9892 ** in duplicate primary key values. 9893 ** 9894 ** The conflicting row in this case is the database row with the matching 9895 ** primary key. 9896 ** 9897 ** <dt>SQLITE_CHANGESET_FOREIGN_KEY<dd> 9898 ** If foreign key handling is enabled, and applying a changeset leaves the 9899 ** database in a state containing foreign key violations, the conflict 9900 ** handler is invoked with CHANGESET_FOREIGN_KEY as the second argument 9901 ** exactly once before the changeset is committed. If the conflict handler 9902 ** returns CHANGESET_OMIT, the changes, including those that caused the 9903 ** foreign key constraint violation, are committed. Or, if it returns 9904 ** CHANGESET_ABORT, the changeset is rolled back. 9905 ** 9906 ** No current or conflicting row information is provided. The only function 9907 ** it is possible to call on the supplied sqlite3_changeset_iter handle 9908 ** is sqlite3changeset_fk_conflicts(). 9909 ** 9910 ** <dt>SQLITE_CHANGESET_CONSTRAINT<dd> 9911 ** If any other constraint violation occurs while applying a change (i.e. 9912 ** a UNIQUE, CHECK or NOT NULL constraint), the conflict handler is 9913 ** invoked with CHANGESET_CONSTRAINT as the second argument. 9914 ** 9915 ** There is no conflicting row in this case. The results of invoking the 9916 ** sqlite3changeset_conflict() API are undefined. 9917 ** 9918 ** </dl> 9919 */ 9920 #define SQLITE_CHANGESET_DATA 1 9921 #define SQLITE_CHANGESET_NOTFOUND 2 9922 #define SQLITE_CHANGESET_CONFLICT 3 9923 #define SQLITE_CHANGESET_CONSTRAINT 4 9924 #define SQLITE_CHANGESET_FOREIGN_KEY 5 9925 9926 /* 9927 ** CAPI3REF: Constants Returned By The Conflict Handler 9928 ** 9929 ** A conflict handler callback must return one of the following three values. 9930 ** 9931 ** <dl> 9932 ** <dt>SQLITE_CHANGESET_OMIT<dd> 9933 ** If a conflict handler returns this value no special action is taken. The 9934 ** change that caused the conflict is not applied. The session module 9935 ** continues to the next change in the changeset. 9936 ** 9937 ** <dt>SQLITE_CHANGESET_REPLACE<dd> 9938 ** This value may only be returned if the second argument to the conflict 9939 ** handler was SQLITE_CHANGESET_DATA or SQLITE_CHANGESET_CONFLICT. If this 9940 ** is not the case, any changes applied so far are rolled back and the 9941 ** call to sqlite3changeset_apply() returns SQLITE_MISUSE. 9942 ** 9943 ** If CHANGESET_REPLACE is returned by an SQLITE_CHANGESET_DATA conflict 9944 ** handler, then the conflicting row is either updated or deleted, depending 9945 ** on the type of change. 9946 ** 9947 ** If CHANGESET_REPLACE is returned by an SQLITE_CHANGESET_CONFLICT conflict 9948 ** handler, then the conflicting row is removed from the database and a 9949 ** second attempt to apply the change is made. If this second attempt fails, 9950 ** the original row is restored to the database before continuing. 9951 ** 9952 ** <dt>SQLITE_CHANGESET_ABORT<dd> 9953 ** If this value is returned, any changes applied so far are rolled back 9954 ** and the call to sqlite3changeset_apply() returns SQLITE_ABORT. 9955 ** </dl> 9956 */ 9957 #define SQLITE_CHANGESET_OMIT 0 9958 #define SQLITE_CHANGESET_REPLACE 1 9959 #define SQLITE_CHANGESET_ABORT 2 9960 9961 /* 9962 ** CAPI3REF: Streaming Versions of API functions. 9963 ** 9964 ** The six streaming API xxx_strm() functions serve similar purposes to the 9965 ** corresponding non-streaming API functions: 9966 ** 9967 ** <table border=1 style="margin-left:8ex;margin-right:8ex"> 9968 ** <tr><th>Streaming function<th>Non-streaming equivalent</th> 9969 ** <tr><td>sqlite3changeset_apply_str<td>[sqlite3changeset_apply] 9970 ** <tr><td>sqlite3changeset_concat_str<td>[sqlite3changeset_concat] 9971 ** <tr><td>sqlite3changeset_invert_str<td>[sqlite3changeset_invert] 9972 ** <tr><td>sqlite3changeset_start_str<td>[sqlite3changeset_start] 9973 ** <tr><td>sqlite3session_changeset_str<td>[sqlite3session_changeset] 9974 ** <tr><td>sqlite3session_patchset_str<td>[sqlite3session_patchset] 9975 ** </table> 9976 ** 9977 ** Non-streaming functions that accept changesets (or patchsets) as input 9978 ** require that the entire changeset be stored in a single buffer in memory. 9979 ** Similarly, those that return a changeset or patchset do so by returning 9980 ** a pointer to a single large buffer allocated using sqlite3_malloc(). 9981 ** Normally this is convenient. However, if an application running in a 9982 ** low-memory environment is required to handle very large changesets, the 9983 ** large contiguous memory allocations required can become onerous. 9984 ** 9985 ** In order to avoid this problem, instead of a single large buffer, input 9986 ** is passed to a streaming API functions by way of a callback function that 9987 ** the sessions module invokes to incrementally request input data as it is 9988 ** required. In all cases, a pair of API function parameters such as 9989 ** 9990 ** <pre> 9991 ** int nChangeset, 9992 ** void *pChangeset, 9993 ** </pre> 9994 ** 9995 ** Is replaced by: 9996 ** 9997 ** <pre> 9998 ** int (*xInput)(void *pIn, void *pData, int *pnData), 9999 ** void *pIn, 10000 ** </pre> 10001 ** 10002 ** Each time the xInput callback is invoked by the sessions module, the first 10003 ** argument passed is a copy of the supplied pIn context pointer. The second 10004 ** argument, pData, points to a buffer (*pnData) bytes in size. Assuming no 10005 ** error occurs the xInput method should copy up to (*pnData) bytes of data 10006 ** into the buffer and set (*pnData) to the actual number of bytes copied 10007 ** before returning SQLITE_OK. If the input is completely exhausted, (*pnData) 10008 ** should be set to zero to indicate this. Or, if an error occurs, an SQLite 10009 ** error code should be returned. In all cases, if an xInput callback returns 10010 ** an error, all processing is abandoned and the streaming API function 10011 ** returns a copy of the error code to the caller. 10012 ** 10013 ** In the case of sqlite3changeset_start_strm(), the xInput callback may be 10014 ** invoked by the sessions module at any point during the lifetime of the 10015 ** iterator. If such an xInput callback returns an error, the iterator enters 10016 ** an error state, whereby all subsequent calls to iterator functions 10017 ** immediately fail with the same error code as returned by xInput. 10018 ** 10019 ** Similarly, streaming API functions that return changesets (or patchsets) 10020 ** return them in chunks by way of a callback function instead of via a 10021 ** pointer to a single large buffer. In this case, a pair of parameters such 10022 ** as: 10023 ** 10024 ** <pre> 10025 ** int *pnChangeset, 10026 ** void **ppChangeset, 10027 ** </pre> 10028 ** 10029 ** Is replaced by: 10030 ** 10031 ** <pre> 10032 ** int (*xOutput)(void *pOut, const void *pData, int nData), 10033 ** void *pOut 10034 ** </pre> 10035 ** 10036 ** The xOutput callback is invoked zero or more times to return data to 10037 ** the application. The first parameter passed to each call is a copy of the 10038 ** pOut pointer supplied by the application. The second parameter, pData, 10039 ** points to a buffer nData bytes in size containing the chunk of output 10040 ** data being returned. If the xOutput callback successfully processes the 10041 ** supplied data, it should return SQLITE_OK to indicate success. Otherwise, 10042 ** it should return some other SQLite error code. In this case processing 10043 ** is immediately abandoned and the streaming API function returns a copy 10044 ** of the xOutput error code to the application. 10045 ** 10046 ** The sessions module never invokes an xOutput callback with the third 10047 ** parameter set to a value less than or equal to zero. Other than this, 10048 ** no guarantees are made as to the size of the chunks of data returned. 10049 */ 10050 SQLITE_API int sqlite3changeset_apply_strm( 10051 sqlite3 *db, /* Apply change to "main" db of this handle */ 10052 int (*xInput)(void *pIn, void *pData, int *pnData), /* Input function */ 10053 void *pIn, /* First arg for xInput */ 10054 int(*xFilter)( 10055 void *pCtx, /* Copy of sixth arg to _apply() */ 10056 const char *zTab /* Table name */ 10057 ), 10058 int(*xConflict)( 10059 void *pCtx, /* Copy of sixth arg to _apply() */ 10060 int eConflict, /* DATA, MISSING, CONFLICT, CONSTRAINT */ 10061 sqlite3_changeset_iter *p /* Handle describing change and conflict */ 10062 ), 10063 void *pCtx /* First argument passed to xConflict */ 10064 ); 10065 SQLITE_API int sqlite3changeset_concat_strm( 10066 int (*xInputA)(void *pIn, void *pData, int *pnData), 10067 void *pInA, 10068 int (*xInputB)(void *pIn, void *pData, int *pnData), 10069 void *pInB, 10070 int (*xOutput)(void *pOut, const void *pData, int nData), 10071 void *pOut 10072 ); 10073 SQLITE_API int sqlite3changeset_invert_strm( 10074 int (*xInput)(void *pIn, void *pData, int *pnData), 10075 void *pIn, 10076 int (*xOutput)(void *pOut, const void *pData, int nData), 10077 void *pOut 10078 ); 10079 SQLITE_API int sqlite3changeset_start_strm( 10080 sqlite3_changeset_iter **pp, 10081 int (*xInput)(void *pIn, void *pData, int *pnData), 10082 void *pIn 10083 ); 10084 SQLITE_API int sqlite3session_changeset_strm( 10085 sqlite3_session *pSession, 10086 int (*xOutput)(void *pOut, const void *pData, int nData), 10087 void *pOut 10088 ); 10089 SQLITE_API int sqlite3session_patchset_strm( 10090 sqlite3_session *pSession, 10091 int (*xOutput)(void *pOut, const void *pData, int nData), 10092 void *pOut 10093 ); 10094 SQLITE_API int sqlite3changegroup_add_strm(sqlite3_changegroup*, 10095 int (*xInput)(void *pIn, void *pData, int *pnData), 10096 void *pIn 10097 ); 10098 SQLITE_API int sqlite3changegroup_output_strm(sqlite3_changegroup*, 10099 int (*xOutput)(void *pOut, const void *pData, int nData), 10100 void *pOut 10101 ); 10102 10103 10104 /* 10105 ** Make sure we can call this stuff from C++. 10106 */ 10107 #ifdef __cplusplus 10108 } 10109 #endif 10110 10111 #endif /* !defined(__SQLITESESSION_H_) && defined(SQLITE_ENABLE_SESSION) */ 10112 10113 /******** End of sqlite3session.h *********/ 10114 /******** Begin file fts5.h *********/ 10115 /* 10116 ** 2014 May 31 10117 ** 10118 ** The author disclaims copyright to this source code. In place of 10119 ** a legal notice, here is a blessing: 10120 ** 10121 ** May you do good and not evil. 10122 ** May you find forgiveness for yourself and forgive others. 10123 ** May you share freely, never taking more than you give. 10124 ** 10125 ****************************************************************************** 10126 ** 10127 ** Interfaces to extend FTS5. Using the interfaces defined in this file, 10128 ** FTS5 may be extended with: 10129 ** 10130 ** * custom tokenizers, and 10131 ** * custom auxiliary functions. 10132 */ 10133 10134 10135 #ifndef _FTS5_H 10136 #define _FTS5_H 10137 10138 10139 #ifdef __cplusplus 10140 extern "C" { 10141 #endif 10142 10143 /************************************************************************* 10144 ** CUSTOM AUXILIARY FUNCTIONS 10145 ** 10146 ** Virtual table implementations may overload SQL functions by implementing 10147 ** the sqlite3_module.xFindFunction() method. 10148 */ 10149 10150 typedef struct Fts5ExtensionApi Fts5ExtensionApi; 10151 typedef struct Fts5Context Fts5Context; 10152 typedef struct Fts5PhraseIter Fts5PhraseIter; 10153 10154 typedef void (*fts5_extension_function)( 10155 const Fts5ExtensionApi *pApi, /* API offered by current FTS version */ 10156 Fts5Context *pFts, /* First arg to pass to pApi functions */ 10157 sqlite3_context *pCtx, /* Context for returning result/error */ 10158 int nVal, /* Number of values in apVal[] array */ 10159 sqlite3_value **apVal /* Array of trailing arguments */ 10160 ); 10161 10162 struct Fts5PhraseIter { 10163 const unsigned char *a; 10164 const unsigned char *b; 10165 }; 10166 10167 /* 10168 ** EXTENSION API FUNCTIONS 10169 ** 10170 ** xUserData(pFts): 10171 ** Return a copy of the context pointer the extension function was 10172 ** registered with. 10173 ** 10174 ** xColumnTotalSize(pFts, iCol, pnToken): 10175 ** If parameter iCol is less than zero, set output variable *pnToken 10176 ** to the total number of tokens in the FTS5 table. Or, if iCol is 10177 ** non-negative but less than the number of columns in the table, return 10178 ** the total number of tokens in column iCol, considering all rows in 10179 ** the FTS5 table. 10180 ** 10181 ** If parameter iCol is greater than or equal to the number of columns 10182 ** in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g. 10183 ** an OOM condition or IO error), an appropriate SQLite error code is 10184 ** returned. 10185 ** 10186 ** xColumnCount(pFts): 10187 ** Return the number of columns in the table. 10188 ** 10189 ** xColumnSize(pFts, iCol, pnToken): 10190 ** If parameter iCol is less than zero, set output variable *pnToken 10191 ** to the total number of tokens in the current row. Or, if iCol is 10192 ** non-negative but less than the number of columns in the table, set 10193 ** *pnToken to the number of tokens in column iCol of the current row. 10194 ** 10195 ** If parameter iCol is greater than or equal to the number of columns 10196 ** in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g. 10197 ** an OOM condition or IO error), an appropriate SQLite error code is 10198 ** returned. 10199 ** 10200 ** This function may be quite inefficient if used with an FTS5 table 10201 ** created with the "columnsize=0" option. 10202 ** 10203 ** xColumnText: 10204 ** This function attempts to retrieve the text of column iCol of the 10205 ** current document. If successful, (*pz) is set to point to a buffer 10206 ** containing the text in utf-8 encoding, (*pn) is set to the size in bytes 10207 ** (not characters) of the buffer and SQLITE_OK is returned. Otherwise, 10208 ** if an error occurs, an SQLite error code is returned and the final values 10209 ** of (*pz) and (*pn) are undefined. 10210 ** 10211 ** xPhraseCount: 10212 ** Returns the number of phrases in the current query expression. 10213 ** 10214 ** xPhraseSize: 10215 ** Returns the number of tokens in phrase iPhrase of the query. Phrases 10216 ** are numbered starting from zero. 10217 ** 10218 ** xInstCount: 10219 ** Set *pnInst to the total number of occurrences of all phrases within 10220 ** the query within the current row. Return SQLITE_OK if successful, or 10221 ** an error code (i.e. SQLITE_NOMEM) if an error occurs. 10222 ** 10223 ** This API can be quite slow if used with an FTS5 table created with the 10224 ** "detail=none" or "detail=column" option. If the FTS5 table is created 10225 ** with either "detail=none" or "detail=column" and "content=" option 10226 ** (i.e. if it is a contentless table), then this API always returns 0. 10227 ** 10228 ** xInst: 10229 ** Query for the details of phrase match iIdx within the current row. 10230 ** Phrase matches are numbered starting from zero, so the iIdx argument 10231 ** should be greater than or equal to zero and smaller than the value 10232 ** output by xInstCount(). 10233 ** 10234 ** Usually, output parameter *piPhrase is set to the phrase number, *piCol 10235 ** to the column in which it occurs and *piOff the token offset of the 10236 ** first token of the phrase. The exception is if the table was created 10237 ** with the offsets=0 option specified. In this case *piOff is always 10238 ** set to -1. 10239 ** 10240 ** Returns SQLITE_OK if successful, or an error code (i.e. SQLITE_NOMEM) 10241 ** if an error occurs. 10242 ** 10243 ** This API can be quite slow if used with an FTS5 table created with the 10244 ** "detail=none" or "detail=column" option. 10245 ** 10246 ** xRowid: 10247 ** Returns the rowid of the current row. 10248 ** 10249 ** xTokenize: 10250 ** Tokenize text using the tokenizer belonging to the FTS5 table. 10251 ** 10252 ** xQueryPhrase(pFts5, iPhrase, pUserData, xCallback): 10253 ** This API function is used to query the FTS table for phrase iPhrase 10254 ** of the current query. Specifically, a query equivalent to: 10255 ** 10256 ** ... FROM ftstable WHERE ftstable MATCH $p ORDER BY rowid 10257 ** 10258 ** with $p set to a phrase equivalent to the phrase iPhrase of the 10259 ** current query is executed. Any column filter that applies to 10260 ** phrase iPhrase of the current query is included in $p. For each 10261 ** row visited, the callback function passed as the fourth argument 10262 ** is invoked. The context and API objects passed to the callback 10263 ** function may be used to access the properties of each matched row. 10264 ** Invoking Api.xUserData() returns a copy of the pointer passed as 10265 ** the third argument to pUserData. 10266 ** 10267 ** If the callback function returns any value other than SQLITE_OK, the 10268 ** query is abandoned and the xQueryPhrase function returns immediately. 10269 ** If the returned value is SQLITE_DONE, xQueryPhrase returns SQLITE_OK. 10270 ** Otherwise, the error code is propagated upwards. 10271 ** 10272 ** If the query runs to completion without incident, SQLITE_OK is returned. 10273 ** Or, if some error occurs before the query completes or is aborted by 10274 ** the callback, an SQLite error code is returned. 10275 ** 10276 ** 10277 ** xSetAuxdata(pFts5, pAux, xDelete) 10278 ** 10279 ** Save the pointer passed as the second argument as the extension functions 10280 ** "auxiliary data". The pointer may then be retrieved by the current or any 10281 ** future invocation of the same fts5 extension function made as part of 10282 ** of the same MATCH query using the xGetAuxdata() API. 10283 ** 10284 ** Each extension function is allocated a single auxiliary data slot for 10285 ** each FTS query (MATCH expression). If the extension function is invoked 10286 ** more than once for a single FTS query, then all invocations share a 10287 ** single auxiliary data context. 10288 ** 10289 ** If there is already an auxiliary data pointer when this function is 10290 ** invoked, then it is replaced by the new pointer. If an xDelete callback 10291 ** was specified along with the original pointer, it is invoked at this 10292 ** point. 10293 ** 10294 ** The xDelete callback, if one is specified, is also invoked on the 10295 ** auxiliary data pointer after the FTS5 query has finished. 10296 ** 10297 ** If an error (e.g. an OOM condition) occurs within this function, an 10298 ** the auxiliary data is set to NULL and an error code returned. If the 10299 ** xDelete parameter was not NULL, it is invoked on the auxiliary data 10300 ** pointer before returning. 10301 ** 10302 ** 10303 ** xGetAuxdata(pFts5, bClear) 10304 ** 10305 ** Returns the current auxiliary data pointer for the fts5 extension 10306 ** function. See the xSetAuxdata() method for details. 10307 ** 10308 ** If the bClear argument is non-zero, then the auxiliary data is cleared 10309 ** (set to NULL) before this function returns. In this case the xDelete, 10310 ** if any, is not invoked. 10311 ** 10312 ** 10313 ** xRowCount(pFts5, pnRow) 10314 ** 10315 ** This function is used to retrieve the total number of rows in the table. 10316 ** In other words, the same value that would be returned by: 10317 ** 10318 ** SELECT count(*) FROM ftstable; 10319 ** 10320 ** xPhraseFirst() 10321 ** This function is used, along with type Fts5PhraseIter and the xPhraseNext 10322 ** method, to iterate through all instances of a single query phrase within 10323 ** the current row. This is the same information as is accessible via the 10324 ** xInstCount/xInst APIs. While the xInstCount/xInst APIs are more convenient 10325 ** to use, this API may be faster under some circumstances. To iterate 10326 ** through instances of phrase iPhrase, use the following code: 10327 ** 10328 ** Fts5PhraseIter iter; 10329 ** int iCol, iOff; 10330 ** for(pApi->xPhraseFirst(pFts, iPhrase, &iter, &iCol, &iOff); 10331 ** iCol>=0; 10332 ** pApi->xPhraseNext(pFts, &iter, &iCol, &iOff) 10333 ** ){ 10334 ** // An instance of phrase iPhrase at offset iOff of column iCol 10335 ** } 10336 ** 10337 ** The Fts5PhraseIter structure is defined above. Applications should not 10338 ** modify this structure directly - it should only be used as shown above 10339 ** with the xPhraseFirst() and xPhraseNext() API methods (and by 10340 ** xPhraseFirstColumn() and xPhraseNextColumn() as illustrated below). 10341 ** 10342 ** This API can be quite slow if used with an FTS5 table created with the 10343 ** "detail=none" or "detail=column" option. If the FTS5 table is created 10344 ** with either "detail=none" or "detail=column" and "content=" option 10345 ** (i.e. if it is a contentless table), then this API always iterates 10346 ** through an empty set (all calls to xPhraseFirst() set iCol to -1). 10347 ** 10348 ** xPhraseNext() 10349 ** See xPhraseFirst above. 10350 ** 10351 ** xPhraseFirstColumn() 10352 ** This function and xPhraseNextColumn() are similar to the xPhraseFirst() 10353 ** and xPhraseNext() APIs described above. The difference is that instead 10354 ** of iterating through all instances of a phrase in the current row, these 10355 ** APIs are used to iterate through the set of columns in the current row 10356 ** that contain one or more instances of a specified phrase. For example: 10357 ** 10358 ** Fts5PhraseIter iter; 10359 ** int iCol; 10360 ** for(pApi->xPhraseFirstColumn(pFts, iPhrase, &iter, &iCol); 10361 ** iCol>=0; 10362 ** pApi->xPhraseNextColumn(pFts, &iter, &iCol) 10363 ** ){ 10364 ** // Column iCol contains at least one instance of phrase iPhrase 10365 ** } 10366 ** 10367 ** This API can be quite slow if used with an FTS5 table created with the 10368 ** "detail=none" option. If the FTS5 table is created with either 10369 ** "detail=none" "content=" option (i.e. if it is a contentless table), 10370 ** then this API always iterates through an empty set (all calls to 10371 ** xPhraseFirstColumn() set iCol to -1). 10372 ** 10373 ** The information accessed using this API and its companion 10374 ** xPhraseFirstColumn() may also be obtained using xPhraseFirst/xPhraseNext 10375 ** (or xInst/xInstCount). The chief advantage of this API is that it is 10376 ** significantly more efficient than those alternatives when used with 10377 ** "detail=column" tables. 10378 ** 10379 ** xPhraseNextColumn() 10380 ** See xPhraseFirstColumn above. 10381 */ 10382 struct Fts5ExtensionApi { 10383 int iVersion; /* Currently always set to 3 */ 10384 10385 void *(*xUserData)(Fts5Context*); 10386 10387 int (*xColumnCount)(Fts5Context*); 10388 int (*xRowCount)(Fts5Context*, sqlite3_int64 *pnRow); 10389 int (*xColumnTotalSize)(Fts5Context*, int iCol, sqlite3_int64 *pnToken); 10390 10391 int (*xTokenize)(Fts5Context*, 10392 const char *pText, int nText, /* Text to tokenize */ 10393 void *pCtx, /* Context passed to xToken() */ 10394 int (*xToken)(void*, int, const char*, int, int, int) /* Callback */ 10395 ); 10396 10397 int (*xPhraseCount)(Fts5Context*); 10398 int (*xPhraseSize)(Fts5Context*, int iPhrase); 10399 10400 int (*xInstCount)(Fts5Context*, int *pnInst); 10401 int (*xInst)(Fts5Context*, int iIdx, int *piPhrase, int *piCol, int *piOff); 10402 10403 sqlite3_int64 (*xRowid)(Fts5Context*); 10404 int (*xColumnText)(Fts5Context*, int iCol, const char **pz, int *pn); 10405 int (*xColumnSize)(Fts5Context*, int iCol, int *pnToken); 10406 10407 int (*xQueryPhrase)(Fts5Context*, int iPhrase, void *pUserData, 10408 int(*)(const Fts5ExtensionApi*,Fts5Context*,void*) 10409 ); 10410 int (*xSetAuxdata)(Fts5Context*, void *pAux, void(*xDelete)(void*)); 10411 void *(*xGetAuxdata)(Fts5Context*, int bClear); 10412 10413 int (*xPhraseFirst)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*, int*); 10414 void (*xPhraseNext)(Fts5Context*, Fts5PhraseIter*, int *piCol, int *piOff); 10415 10416 int (*xPhraseFirstColumn)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*); 10417 void (*xPhraseNextColumn)(Fts5Context*, Fts5PhraseIter*, int *piCol); 10418 }; 10419 10420 /* 10421 ** CUSTOM AUXILIARY FUNCTIONS 10422 *************************************************************************/ 10423 10424 /************************************************************************* 10425 ** CUSTOM TOKENIZERS 10426 ** 10427 ** Applications may also register custom tokenizer types. A tokenizer 10428 ** is registered by providing fts5 with a populated instance of the 10429 ** following structure. All structure methods must be defined, setting 10430 ** any member of the fts5_tokenizer struct to NULL leads to undefined 10431 ** behaviour. The structure methods are expected to function as follows: 10432 ** 10433 ** xCreate: 10434 ** This function is used to allocate and initialize a tokenizer instance. 10435 ** A tokenizer instance is required to actually tokenize text. 10436 ** 10437 ** The first argument passed to this function is a copy of the (void*) 10438 ** pointer provided by the application when the fts5_tokenizer object 10439 ** was registered with FTS5 (the third argument to xCreateTokenizer()). 10440 ** The second and third arguments are an array of nul-terminated strings 10441 ** containing the tokenizer arguments, if any, specified following the 10442 ** tokenizer name as part of the CREATE VIRTUAL TABLE statement used 10443 ** to create the FTS5 table. 10444 ** 10445 ** The final argument is an output variable. If successful, (*ppOut) 10446 ** should be set to point to the new tokenizer handle and SQLITE_OK 10447 ** returned. If an error occurs, some value other than SQLITE_OK should 10448 ** be returned. In this case, fts5 assumes that the final value of *ppOut 10449 ** is undefined. 10450 ** 10451 ** xDelete: 10452 ** This function is invoked to delete a tokenizer handle previously 10453 ** allocated using xCreate(). Fts5 guarantees that this function will 10454 ** be invoked exactly once for each successful call to xCreate(). 10455 ** 10456 ** xTokenize: 10457 ** This function is expected to tokenize the nText byte string indicated 10458 ** by argument pText. pText may or may not be nul-terminated. The first 10459 ** argument passed to this function is a pointer to an Fts5Tokenizer object 10460 ** returned by an earlier call to xCreate(). 10461 ** 10462 ** The second argument indicates the reason that FTS5 is requesting 10463 ** tokenization of the supplied text. This is always one of the following 10464 ** four values: 10465 ** 10466 ** <ul><li> <b>FTS5_TOKENIZE_DOCUMENT</b> - A document is being inserted into 10467 ** or removed from the FTS table. The tokenizer is being invoked to 10468 ** determine the set of tokens to add to (or delete from) the 10469 ** FTS index. 10470 ** 10471 ** <li> <b>FTS5_TOKENIZE_QUERY</b> - A MATCH query is being executed 10472 ** against the FTS index. The tokenizer is being called to tokenize 10473 ** a bareword or quoted string specified as part of the query. 10474 ** 10475 ** <li> <b>(FTS5_TOKENIZE_QUERY | FTS5_TOKENIZE_PREFIX)</b> - Same as 10476 ** FTS5_TOKENIZE_QUERY, except that the bareword or quoted string is 10477 ** followed by a "*" character, indicating that the last token 10478 ** returned by the tokenizer will be treated as a token prefix. 10479 ** 10480 ** <li> <b>FTS5_TOKENIZE_AUX</b> - The tokenizer is being invoked to 10481 ** satisfy an fts5_api.xTokenize() request made by an auxiliary 10482 ** function. Or an fts5_api.xColumnSize() request made by the same 10483 ** on a columnsize=0 database. 10484 ** </ul> 10485 ** 10486 ** For each token in the input string, the supplied callback xToken() must 10487 ** be invoked. The first argument to it should be a copy of the pointer 10488 ** passed as the second argument to xTokenize(). The third and fourth 10489 ** arguments are a pointer to a buffer containing the token text, and the 10490 ** size of the token in bytes. The 4th and 5th arguments are the byte offsets 10491 ** of the first byte of and first byte immediately following the text from 10492 ** which the token is derived within the input. 10493 ** 10494 ** The second argument passed to the xToken() callback ("tflags") should 10495 ** normally be set to 0. The exception is if the tokenizer supports 10496 ** synonyms. In this case see the discussion below for details. 10497 ** 10498 ** FTS5 assumes the xToken() callback is invoked for each token in the 10499 ** order that they occur within the input text. 10500 ** 10501 ** If an xToken() callback returns any value other than SQLITE_OK, then 10502 ** the tokenization should be abandoned and the xTokenize() method should 10503 ** immediately return a copy of the xToken() return value. Or, if the 10504 ** input buffer is exhausted, xTokenize() should return SQLITE_OK. Finally, 10505 ** if an error occurs with the xTokenize() implementation itself, it 10506 ** may abandon the tokenization and return any error code other than 10507 ** SQLITE_OK or SQLITE_DONE. 10508 ** 10509 ** SYNONYM SUPPORT 10510 ** 10511 ** Custom tokenizers may also support synonyms. Consider a case in which a 10512 ** user wishes to query for a phrase such as "first place". Using the 10513 ** built-in tokenizers, the FTS5 query 'first + place' will match instances 10514 ** of "first place" within the document set, but not alternative forms 10515 ** such as "1st place". In some applications, it would be better to match 10516 ** all instances of "first place" or "1st place" regardless of which form 10517 ** the user specified in the MATCH query text. 10518 ** 10519 ** There are several ways to approach this in FTS5: 10520 ** 10521 ** <ol><li> By mapping all synonyms to a single token. In this case, the 10522 ** In the above example, this means that the tokenizer returns the 10523 ** same token for inputs "first" and "1st". Say that token is in 10524 ** fact "first", so that when the user inserts the document "I won 10525 ** 1st place" entries are added to the index for tokens "i", "won", 10526 ** "first" and "place". If the user then queries for '1st + place', 10527 ** the tokenizer substitutes "first" for "1st" and the query works 10528 ** as expected. 10529 ** 10530 ** <li> By adding multiple synonyms for a single term to the FTS index. 10531 ** In this case, when tokenizing query text, the tokenizer may 10532 ** provide multiple synonyms for a single term within the document. 10533 ** FTS5 then queries the index for each synonym individually. For 10534 ** example, faced with the query: 10535 ** 10536 ** <codeblock> 10537 ** ... MATCH 'first place'</codeblock> 10538 ** 10539 ** the tokenizer offers both "1st" and "first" as synonyms for the 10540 ** first token in the MATCH query and FTS5 effectively runs a query 10541 ** similar to: 10542 ** 10543 ** <codeblock> 10544 ** ... MATCH '(first OR 1st) place'</codeblock> 10545 ** 10546 ** except that, for the purposes of auxiliary functions, the query 10547 ** still appears to contain just two phrases - "(first OR 1st)" 10548 ** being treated as a single phrase. 10549 ** 10550 ** <li> By adding multiple synonyms for a single term to the FTS index. 10551 ** Using this method, when tokenizing document text, the tokenizer 10552 ** provides multiple synonyms for each token. So that when a 10553 ** document such as "I won first place" is tokenized, entries are 10554 ** added to the FTS index for "i", "won", "first", "1st" and 10555 ** "place". 10556 ** 10557 ** This way, even if the tokenizer does not provide synonyms 10558 ** when tokenizing query text (it should not - to do would be 10559 ** inefficient), it doesn't matter if the user queries for 10560 ** 'first + place' or '1st + place', as there are entires in the 10561 ** FTS index corresponding to both forms of the first token. 10562 ** </ol> 10563 ** 10564 ** Whether it is parsing document or query text, any call to xToken that 10565 ** specifies a <i>tflags</i> argument with the FTS5_TOKEN_COLOCATED bit 10566 ** is considered to supply a synonym for the previous token. For example, 10567 ** when parsing the document "I won first place", a tokenizer that supports 10568 ** synonyms would call xToken() 5 times, as follows: 10569 ** 10570 ** <codeblock> 10571 ** xToken(pCtx, 0, "i", 1, 0, 1); 10572 ** xToken(pCtx, 0, "won", 3, 2, 5); 10573 ** xToken(pCtx, 0, "first", 5, 6, 11); 10574 ** xToken(pCtx, FTS5_TOKEN_COLOCATED, "1st", 3, 6, 11); 10575 ** xToken(pCtx, 0, "place", 5, 12, 17); 10576 **</codeblock> 10577 ** 10578 ** It is an error to specify the FTS5_TOKEN_COLOCATED flag the first time 10579 ** xToken() is called. Multiple synonyms may be specified for a single token 10580 ** by making multiple calls to xToken(FTS5_TOKEN_COLOCATED) in sequence. 10581 ** There is no limit to the number of synonyms that may be provided for a 10582 ** single token. 10583 ** 10584 ** In many cases, method (1) above is the best approach. It does not add 10585 ** extra data to the FTS index or require FTS5 to query for multiple terms, 10586 ** so it is efficient in terms of disk space and query speed. However, it 10587 ** does not support prefix queries very well. If, as suggested above, the 10588 ** token "first" is subsituted for "1st" by the tokenizer, then the query: 10589 ** 10590 ** <codeblock> 10591 ** ... MATCH '1s*'</codeblock> 10592 ** 10593 ** will not match documents that contain the token "1st" (as the tokenizer 10594 ** will probably not map "1s" to any prefix of "first"). 10595 ** 10596 ** For full prefix support, method (3) may be preferred. In this case, 10597 ** because the index contains entries for both "first" and "1st", prefix 10598 ** queries such as 'fi*' or '1s*' will match correctly. However, because 10599 ** extra entries are added to the FTS index, this method uses more space 10600 ** within the database. 10601 ** 10602 ** Method (2) offers a midpoint between (1) and (3). Using this method, 10603 ** a query such as '1s*' will match documents that contain the literal 10604 ** token "1st", but not "first" (assuming the tokenizer is not able to 10605 ** provide synonyms for prefixes). However, a non-prefix query like '1st' 10606 ** will match against "1st" and "first". This method does not require 10607 ** extra disk space, as no extra entries are added to the FTS index. 10608 ** On the other hand, it may require more CPU cycles to run MATCH queries, 10609 ** as separate queries of the FTS index are required for each synonym. 10610 ** 10611 ** When using methods (2) or (3), it is important that the tokenizer only 10612 ** provide synonyms when tokenizing document text (method (2)) or query 10613 ** text (method (3)), not both. Doing so will not cause any errors, but is 10614 ** inefficient. 10615 */ 10616 typedef struct Fts5Tokenizer Fts5Tokenizer; 10617 typedef struct fts5_tokenizer fts5_tokenizer; 10618 struct fts5_tokenizer { 10619 int (*xCreate)(void*, const char **azArg, int nArg, Fts5Tokenizer **ppOut); 10620 void (*xDelete)(Fts5Tokenizer*); 10621 int (*xTokenize)(Fts5Tokenizer*, 10622 void *pCtx, 10623 int flags, /* Mask of FTS5_TOKENIZE_* flags */ 10624 const char *pText, int nText, 10625 int (*xToken)( 10626 void *pCtx, /* Copy of 2nd argument to xTokenize() */ 10627 int tflags, /* Mask of FTS5_TOKEN_* flags */ 10628 const char *pToken, /* Pointer to buffer containing token */ 10629 int nToken, /* Size of token in bytes */ 10630 int iStart, /* Byte offset of token within input text */ 10631 int iEnd /* Byte offset of end of token within input text */ 10632 ) 10633 ); 10634 }; 10635 10636 /* Flags that may be passed as the third argument to xTokenize() */ 10637 #define FTS5_TOKENIZE_QUERY 0x0001 10638 #define FTS5_TOKENIZE_PREFIX 0x0002 10639 #define FTS5_TOKENIZE_DOCUMENT 0x0004 10640 #define FTS5_TOKENIZE_AUX 0x0008 10641 10642 /* Flags that may be passed by the tokenizer implementation back to FTS5 10643 ** as the third argument to the supplied xToken callback. */ 10644 #define FTS5_TOKEN_COLOCATED 0x0001 /* Same position as prev. token */ 10645 10646 /* 10647 ** END OF CUSTOM TOKENIZERS 10648 *************************************************************************/ 10649 10650 /************************************************************************* 10651 ** FTS5 EXTENSION REGISTRATION API 10652 */ 10653 typedef struct fts5_api fts5_api; 10654 struct fts5_api { 10655 int iVersion; /* Currently always set to 2 */ 10656 10657 /* Create a new tokenizer */ 10658 int (*xCreateTokenizer)( 10659 fts5_api *pApi, 10660 const char *zName, 10661 void *pContext, 10662 fts5_tokenizer *pTokenizer, 10663 void (*xDestroy)(void*) 10664 ); 10665 10666 /* Find an existing tokenizer */ 10667 int (*xFindTokenizer)( 10668 fts5_api *pApi, 10669 const char *zName, 10670 void **ppContext, 10671 fts5_tokenizer *pTokenizer 10672 ); 10673 10674 /* Create a new auxiliary function */ 10675 int (*xCreateFunction)( 10676 fts5_api *pApi, 10677 const char *zName, 10678 void *pContext, 10679 fts5_extension_function xFunction, 10680 void (*xDestroy)(void*) 10681 ); 10682 }; 10683 10684 /* 10685 ** END OF REGISTRATION API 10686 *************************************************************************/ 10687 10688 #ifdef __cplusplus 10689 } /* end of the 'extern "C"' block */ 10690 #endif 10691 10692 #endif /* _FTS5_H */ 10693 10694 /******** End of fts5.h *********/ 10695