third_party/sqlite/sqlite-src-3080704/src/sqlite.h.in - Issue 2363173002: [sqlite] Remove obsolete reference version 3.8.7.4.

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Issue 2363173002: [sqlite] Remove obsolete reference version 3.8.7.4. (Closed)

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1 /*

2 ** 2001 September 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 suppose 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 ** Add the ability to override 'extern'

47 */

48 #ifndef SQLITE_EXTERN

49 # define SQLITE_EXTERN extern

50 #endif

51

52 /*

53 ** These no-op macros are used in front of interfaces to mark those

54 ** interfaces as either deprecated or experimental. New applications

55 ** should not use deprecated interfaces - they are support for backwards

56 ** compatibility only. Application writers should be aware that

57 ** experimental interfaces are subject to change in point releases.

58 **

59 ** These macros used to resolve to various kinds of compiler magic that

60 ** would generate warning messages when they were used. But that

61 ** compiler magic ended up generating such a flurry of bug reports

62 ** that we have taken it all out and gone back to using simple

63 ** noop macros.

64 */

65 #define SQLITE_DEPRECATED

66 #define SQLITE_EXPERIMENTAL

67

68 /*

69 ** Ensure these symbols were not defined by some previous header file.

70 */

71 #ifdef SQLITE_VERSION

72 # undef SQLITE_VERSION

73 #endif

74 #ifdef SQLITE_VERSION_NUMBER

75 # undef SQLITE_VERSION_NUMBER

76 #endif

77

78 /*

79 ** CAPI3REF: Compile-Time Library Version Numbers

80 **

81 ** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header

82 ** evaluates to a string literal that is the SQLite version in the

83 ** format "X.Y.Z" where X is the major version number (always 3 for

84 ** SQLite3) and Y is the minor version number and Z is the release number.)^

85 ** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer

86 ** with the value (X1000000 + Y1000 + Z) where X, Y, and Z are the same

87 ** numbers used in [SQLITE_VERSION].)^

88 ** The SQLITE_VERSION_NUMBER for any given release of SQLite will also

89 ** be larger than the release from which it is derived. Either Y will

90 ** be held constant and Z will be incremented or else Y will be incremented

91 ** and Z will be reset to zero.

92 **

93 ** Since version 3.6.18, SQLite source code has been stored in the

94 ** <a href="http://www.fossil-scm.org/">Fossil configuration management

95 ** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to

96 ** a string which identifies a particular check-in of SQLite

97 ** within its configuration management system. ^The SQLITE_SOURCE_ID

98 ** string contains the date and time of the check-in (UTC) and an SHA1

99 ** hash of the entire source tree.

100 **

101 ** See also: [sqlite3_libversion()],

102 ** [sqlite3_libversion_number()], [sqlite3_sourceid()],

103 ** [sqlite_version()] and [sqlite_source_id()].

104 */

105 #define SQLITE_VERSION "--VERS--"

106 #define SQLITE_VERSION_NUMBER --VERSION-NUMBER--

107 #define SQLITE_SOURCE_ID "--SOURCE-ID--"

108

109 /*

110 ** CAPI3REF: Run-Time Library Version Numbers

111 ** KEYWORDS: sqlite3_version, sqlite3_sourceid

112 **

113 ** These interfaces provide the same information as the [SQLITE_VERSION],

114 ** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros

115 ** but are associated with the library instead of the header file. ^(Cautious

116 ** programmers might include assert() statements in their application to

117 ** verify that values returned by these interfaces match the macros in

118 ** the header, and thus insure that the application is

119 ** compiled with matching library and header files.

120 **

121 ** <blockquote><pre>

122 ** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );

123 ** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 );

124 ** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );

125 ** </pre></blockquote>)^

126 **

127 ** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION]

128 ** macro. ^The sqlite3_libversion() function returns a pointer to the

129 ** to the sqlite3_version[] string constant. The sqlite3_libversion()

130 ** function is provided for use in DLLs since DLL users usually do not have

131 ** direct access to string constants within the DLL. ^The

132 ** sqlite3_libversion_number() function returns an integer equal to

133 ** [SQLITE_VERSION_NUMBER]. ^The sqlite3_sourceid() function returns

134 ** a pointer to a string constant whose value is the same as the

135 ** [SQLITE_SOURCE_ID] C preprocessor macro.

136 **

137 ** See also: [sqlite_version()] and [sqlite_source_id()].

138 */

139 SQLITE_EXTERN const char sqlite3_version[];

140 const char *sqlite3_libversion(void);

141 const char *sqlite3_sourceid(void);

142 int sqlite3_libversion_number(void);

143

144 /*

145 ** CAPI3REF: Run-Time Library Compilation Options Diagnostics

146 **

147 ** ^The sqlite3_compileoption_used() function returns 0 or 1

148 ** indicating whether the specified option was defined at

149 ** compile time. ^The SQLITE_ prefix may be omitted from the

150 ** option name passed to sqlite3_compileoption_used().

151 **

152 ** ^The sqlite3_compileoption_get() function allows iterating

153 ** over the list of options that were defined at compile time by

154 ** returning the N-th compile time option string. ^If N is out of range,

155 ** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_

156 ** prefix is omitted from any strings returned by

157 ** sqlite3_compileoption_get().

158 **

159 ** ^Support for the diagnostic functions sqlite3_compileoption_used()

160 ** and sqlite3_compileoption_get() may be omitted by specifying the

161 ** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time.

162 **

163 ** See also: SQL functions [sqlite_compileoption_used()] and

164 ** [sqlite_compileoption_get()] and the [compile_options pragma].

165 */

166 #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS

167 int sqlite3_compileoption_used(const char *zOptName);

168 const char *sqlite3_compileoption_get(int N);

169 #endif

170

171 /*

172 ** CAPI3REF: Test To See If The Library Is Threadsafe

173 **

174 ** ^The sqlite3_threadsafe() function returns zero if and only if

175 ** SQLite was compiled with mutexing code omitted due to the

176 ** [SQLITE_THREADSAFE] compile-time option being set to 0.

177 **

178 ** SQLite can be compiled with or without mutexes. When

179 ** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes

180 ** are enabled and SQLite is threadsafe. When the

181 ** [SQLITE_THREADSAFE] macro is 0,

182 ** the mutexes are omitted. Without the mutexes, it is not safe

183 ** to use SQLite concurrently from more than one thread.

184 **

185 ** Enabling mutexes incurs a measurable performance penalty.

186 ** So if speed is of utmost importance, it makes sense to disable

187 ** the mutexes. But for maximum safety, mutexes should be enabled.

188 ** ^The default behavior is for mutexes to be enabled.

189 **

190 ** This interface can be used by an application to make sure that the

191 ** version of SQLite that it is linking against was compiled with

192 ** the desired setting of the [SQLITE_THREADSAFE] macro.

193 **

194 ** This interface only reports on the compile-time mutex setting

195 ** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with

196 ** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but

197 ** can be fully or partially disabled using a call to [sqlite3_config()]

198 ** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD],

199 ** or [SQLITE_CONFIG_MUTEX]. ^(The return value of the

200 ** sqlite3_threadsafe() function shows only the compile-time setting of

201 ** thread safety, not any run-time changes to that setting made by

202 ** sqlite3_config(). In other words, the return value from sqlite3_threadsafe()

203 ** is unchanged by calls to sqlite3_config().)^

204 **

205 ** See the [threading mode] documentation for additional information.

206 */

207 int sqlite3_threadsafe(void);

208

209 /*

210 ** CAPI3REF: Database Connection Handle

211 ** KEYWORDS: {database connection} {database connections}

212 **

213 ** Each open SQLite database is represented by a pointer to an instance of

214 ** the opaque structure named "sqlite3". It is useful to think of an sqlite3

215 ** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and

216 ** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]

217 ** and [sqlite3_close_v2()] are its destructors. There are many other

218 ** interfaces (such as

219 ** [sqlite3_prepare_v2()], [sqlite3_create_function()], and

220 ** [sqlite3_busy_timeout()] to name but three) that are methods on an

221 ** sqlite3 object.

222 */

223 typedef struct sqlite3 sqlite3;

224

225 /*

226 ** CAPI3REF: 64-Bit Integer Types

227 ** KEYWORDS: sqlite_int64 sqlite_uint64

228 **

229 ** Because there is no cross-platform way to specify 64-bit integer types

230 ** SQLite includes typedefs for 64-bit signed and unsigned integers.

231 **

232 ** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.

233 ** The sqlite_int64 and sqlite_uint64 types are supported for backwards

234 ** compatibility only.

235 **

236 ** ^The sqlite3_int64 and sqlite_int64 types can store integer values

237 ** between -9223372036854775808 and +9223372036854775807 inclusive. ^The

238 ** sqlite3_uint64 and sqlite_uint64 types can store integer values

239 ** between 0 and +18446744073709551615 inclusive.

240 */

241 #ifdef SQLITE_INT64_TYPE

242 typedef SQLITE_INT64_TYPE sqlite_int64;

243 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;

244 #elif defined(_MSC_VER) \|\| defined(__BORLANDC__)

245 typedef __int64 sqlite_int64;

246 typedef unsigned __int64 sqlite_uint64;

247 #else

248 typedef long long int sqlite_int64;

249 typedef unsigned long long int sqlite_uint64;

250 #endif

251 typedef sqlite_int64 sqlite3_int64;

252 typedef sqlite_uint64 sqlite3_uint64;

253

254 /*

255 ** If compiling for a processor that lacks floating point support,

256 ** substitute integer for floating-point.

257 */

258 #ifdef SQLITE_OMIT_FLOATING_POINT

259 # define double sqlite3_int64

260 #endif

261

262 /*

263 ** CAPI3REF: Closing A Database Connection

264 **

265 ** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors

266 ** for the [sqlite3] object.

267 ** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if

268 ** the [sqlite3] object is successfully destroyed and all associated

269 ** resources are deallocated.

270 **

271 ** ^If the database connection is associated with unfinalized prepared

272 ** statements or unfinished sqlite3_backup objects then sqlite3_close()

273 ** will leave the database connection open and return [SQLITE_BUSY].

274 ** ^If sqlite3_close_v2() is called with unfinalized prepared statements

275 ** and/or unfinished sqlite3_backups, then the database connection becomes

276 ** an unusable "zombie" which will automatically be deallocated when the

277 ** last prepared statement is finalized or the last sqlite3_backup is

278 ** finished. The sqlite3_close_v2() interface is intended for use with

279 ** host languages that are garbage collected, and where the order in which

280 ** destructors are called is arbitrary.

281 **

282 ** Applications should [sqlite3_finalize \| finalize] all [prepared statements],

283 ** [sqlite3_blob_close \| close] all [BLOB handles], and

284 ** [sqlite3_backup_finish \| finish] all [sqlite3_backup] objects associated

285 ** with the [sqlite3] object prior to attempting to close the object. ^If

286 ** sqlite3_close_v2() is called on a [database connection] that still has

287 ** outstanding [prepared statements], [BLOB handles], and/or

288 ** [sqlite3_backup] objects then it returns [SQLITE_OK] and the deallocation

289 ** of resources is deferred until all [prepared statements], [BLOB handles],

290 ** and [sqlite3_backup] objects are also destroyed.

291 **

292 ** ^If an [sqlite3] object is destroyed while a transaction is open,

293 ** the transaction is automatically rolled back.

294 **

295 ** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)]

296 ** must be either a NULL

297 ** pointer or an [sqlite3] object pointer obtained

298 ** from [sqlite3_open()], [sqlite3_open16()], or

299 ** [sqlite3_open_v2()], and not previously closed.

300 ** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer

301 ** argument is a harmless no-op.

302 */

303 int sqlite3_close(sqlite3*);

304 int sqlite3_close_v2(sqlite3*);

305

306 /*

307 ** The type for a callback function.

308 ** This is legacy and deprecated. It is included for historical

309 ** compatibility and is not documented.

310 */

311 typedef int (sqlite3_callback)(void,int,char, char);

312

313 /*

314 ** CAPI3REF: One-Step Query Execution Interface

315 **

316 ** The sqlite3_exec() interface is a convenience wrapper around

317 ** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],

318 ** that allows an application to run multiple statements of SQL

319 ** without having to use a lot of C code.

320 **

321 ** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,

322 ** semicolon-separate SQL statements passed into its 2nd argument,

323 ** in the context of the [database connection] passed in as its 1st

324 ** argument. ^If the callback function of the 3rd argument to

325 ** sqlite3_exec() is not NULL, then it is invoked for each result row

326 ** coming out of the evaluated SQL statements. ^The 4th argument to

327 ** sqlite3_exec() is relayed through to the 1st argument of each

328 ** callback invocation. ^If the callback pointer to sqlite3_exec()

329 ** is NULL, then no callback is ever invoked and result rows are

330 ** ignored.

331 **

332 ** ^If an error occurs while evaluating the SQL statements passed into

333 ** sqlite3_exec(), then execution of the current statement stops and

334 ** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec()

335 ** is not NULL then any error message is written into memory obtained

336 ** from [sqlite3_malloc()] and passed back through the 5th parameter.

337 ** To avoid memory leaks, the application should invoke [sqlite3_free()]

338 ** on error message strings returned through the 5th parameter of

339 ** of sqlite3_exec() after the error message string is no longer needed.

340 ** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors

341 ** occur, then sqlite3_exec() sets the pointer in its 5th parameter to

342 ** NULL before returning.

343 **

344 ** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()

345 ** routine returns SQLITE_ABORT without invoking the callback again and

346 ** without running any subsequent SQL statements.

347 **

348 ** ^The 2nd argument to the sqlite3_exec() callback function is the

349 ** number of columns in the result. ^The 3rd argument to the sqlite3_exec()

350 ** callback is an array of pointers to strings obtained as if from

351 ** [sqlite3_column_text()], one for each column. ^If an element of a

352 ** result row is NULL then the corresponding string pointer for the

353 ** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the

354 ** sqlite3_exec() callback is an array of pointers to strings where each

355 ** entry represents the name of corresponding result column as obtained

356 ** from [sqlite3_column_name()].

357 **

358 ** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer

359 ** to an empty string, or a pointer that contains only whitespace and/or

360 ** SQL comments, then no SQL statements are evaluated and the database

361 ** is not changed.

362 **

363 ** Restrictions:

364 **

365 ** <ul>

366 ** <li> The application must insure that the 1st parameter to sqlite3_exec()

367 ** is a valid and open [database connection].

368 ** <li> The application must not close the [database connection] specified by

369 ** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.

370 ** <li> The application must not modify the SQL statement text passed into

371 ** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.

372 ** </ul>

373 */

374 int sqlite3_exec(

375 sqlite3, / An open database */

376 const char sql, / SQL to be evaluated */

377 int (callback)(void,int,char,char), /* Callback function */

378 void , / 1st argument to callback */

379 char *errmsg / Error msg written here */

380 );

381

382 /*

383 ** CAPI3REF: Result Codes

384 ** KEYWORDS: {result code definitions}

385 **

386 ** Many SQLite functions return an integer result code from the set shown

387 ** here in order to indicate success or failure.

388 **

389 ** New error codes may be added in future versions of SQLite.

390 **

391 ** See also: [extended result code definitions]

392 */

393 #define SQLITE_OK 0 /* Successful result */

394 /* beginning-of-error-codes */

395 #define SQLITE_ERROR 1 /* SQL error or missing database */

396 #define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */

397 #define SQLITE_PERM 3 /* Access permission denied */

398 #define SQLITE_ABORT 4 /* Callback routine requested an abort */

399 #define SQLITE_BUSY 5 /* The database file is locked */

400 #define SQLITE_LOCKED 6 /* A table in the database is locked */

401 #define SQLITE_NOMEM 7 /* A malloc() failed */

402 #define SQLITE_READONLY 8 /* Attempt to write a readonly database */

403 #define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/

404 #define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */

405 #define SQLITE_CORRUPT 11 /* The database disk image is malformed */

406 #define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */

407 #define SQLITE_FULL 13 /* Insertion failed because database is full */

408 #define SQLITE_CANTOPEN 14 /* Unable to open the database file */

409 #define SQLITE_PROTOCOL 15 /* Database lock protocol error */

410 #define SQLITE_EMPTY 16 /* Database is empty */

411 #define SQLITE_SCHEMA 17 /* The database schema changed */

412 #define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */

413 #define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */

414 #define SQLITE_MISMATCH 20 /* Data type mismatch */

415 #define SQLITE_MISUSE 21 /* Library used incorrectly */

416 #define SQLITE_NOLFS 22 /* Uses OS features not supported on host */

417 #define SQLITE_AUTH 23 /* Authorization denied */

418 #define SQLITE_FORMAT 24 /* Auxiliary database format error */

419 #define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */

420 #define SQLITE_NOTADB 26 /* File opened that is not a database file */

421 #define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */

422 #define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */

423 #define SQLITE_ROW 100 /* sqlite3_step() has another row ready */

424 #define SQLITE_DONE 101 /* sqlite3_step() has finished executing */

425 /* end-of-error-codes */

426

427 /*

428 ** CAPI3REF: Extended Result Codes

429 ** KEYWORDS: {extended result code definitions}

430 **

431 ** In its default configuration, SQLite API routines return one of 30 integer

432 ** [result codes]. However, experience has shown that many of

433 ** these result codes are too coarse-grained. They do not provide as

434 ** much information about problems as programmers might like. In an effort to

435 ** address this, newer versions of SQLite (version 3.3.8 and later) include

436 ** support for additional result codes that provide more detailed information

437 ** about errors. These [extended result codes] are enabled or disabled

438 ** on a per database connection basis using the

439 ** [sqlite3_extended_result_codes()] API. Or, the extended code for

440 ** the most recent error can be obtained using

441 ** [sqlite3_extended_errcode()].

442 */

443 #define SQLITE_IOERR_READ (SQLITE_IOERR \| (1<<8))

444 #define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR \| (2<<8))

445 #define SQLITE_IOERR_WRITE (SQLITE_IOERR \| (3<<8))

446 #define SQLITE_IOERR_FSYNC (SQLITE_IOERR \| (4<<8))

447 #define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR \| (5<<8))

448 #define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR \| (6<<8))

449 #define SQLITE_IOERR_FSTAT (SQLITE_IOERR \| (7<<8))

450 #define SQLITE_IOERR_UNLOCK (SQLITE_IOERR \| (8<<8))

451 #define SQLITE_IOERR_RDLOCK (SQLITE_IOERR \| (9<<8))

452 #define SQLITE_IOERR_DELETE (SQLITE_IOERR \| (10<<8))

453 #define SQLITE_IOERR_BLOCKED (SQLITE_IOERR \| (11<<8))

454 #define SQLITE_IOERR_NOMEM (SQLITE_IOERR \| (12<<8))

455 #define SQLITE_IOERR_ACCESS (SQLITE_IOERR \| (13<<8))

456 #define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR \| (14<<8))

457 #define SQLITE_IOERR_LOCK (SQLITE_IOERR \| (15<<8))

458 #define SQLITE_IOERR_CLOSE (SQLITE_IOERR \| (16<<8))

459 #define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR \| (17<<8))

460 #define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR \| (18<<8))

461 #define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR \| (19<<8))

462 #define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR \| (20<<8))

463 #define SQLITE_IOERR_SHMMAP (SQLITE_IOERR \| (21<<8))

464 #define SQLITE_IOERR_SEEK (SQLITE_IOERR \| (22<<8))

465 #define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR \| (23<<8))

466 #define SQLITE_IOERR_MMAP (SQLITE_IOERR \| (24<<8))

467 #define SQLITE_IOERR_GETTEMPPATH (SQLITE_IOERR \| (25<<8))

468 #define SQLITE_IOERR_CONVPATH (SQLITE_IOERR \| (26<<8))

469 #define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED \| (1<<8))

470 #define SQLITE_BUSY_RECOVERY (SQLITE_BUSY \| (1<<8))

471 #define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY \| (2<<8))

472 #define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN \| (1<<8))

473 #define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN \| (2<<8))

474 #define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN \| (3<<8))

475 #define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN \| (4<<8))

476 #define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT \| (1<<8))

477 #define SQLITE_READONLY_RECOVERY (SQLITE_READONLY \| (1<<8))

478 #define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY \| (2<<8))

479 #define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY \| (3<<8))

480 #define SQLITE_READONLY_DBMOVED (SQLITE_READONLY \| (4<<8))

481 #define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT \| (2<<8))

482 #define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT \| (1<<8))

483 #define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT \| (2<<8))

484 #define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT \| (3<<8))

485 #define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT \| (4<<8))

486 #define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT \| (5<<8))

487 #define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT \| (6<<8))

488 #define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT \| (7<<8))

489 #define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT \| (8<<8))

490 #define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT \| (9<<8))

491 #define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT \|(10<<8))

492 #define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE \| (1<<8))

493 #define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE \| (2<<8))

494 #define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING \| (1<<8))

495 #define SQLITE_AUTH_USER (SQLITE_AUTH \| (1<<8))

496

497 /*

498 ** CAPI3REF: Flags For File Open Operations

499 **

500 ** These bit values are intended for use in the

501 ** 3rd parameter to the [sqlite3_open_v2()] interface and

502 ** in the 4th parameter to the [sqlite3_vfs.xOpen] method.

503 */

504 #define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */

505 #define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */

506 #define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */

507 #define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */

508 #define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */

509 #define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */

510 #define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */

511 #define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */

512 #define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */

513 #define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */

514 #define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */

515 #define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */

516 #define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */

517 #define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */

518 #define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */

519 #define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */

520 #define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */

521 #define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */

522 #define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */

523 #define SQLITE_OPEN_WAL 0x00080000 /* VFS only */

524

525 /* Reserved: 0x00F00000 */

526

527 /*

528 ** CAPI3REF: Device Characteristics

529 **

530 ** The xDeviceCharacteristics method of the [sqlite3_io_methods]

531 ** object returns an integer which is a vector of these

532 ** bit values expressing I/O characteristics of the mass storage

533 ** device that holds the file that the [sqlite3_io_methods]

534 ** refers to.

535 **

536 ** The SQLITE_IOCAP_ATOMIC property means that all writes of

537 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values

538 ** mean that writes of blocks that are nnn bytes in size and

539 ** are aligned to an address which is an integer multiple of

540 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means

541 ** that when data is appended to a file, the data is appended

542 ** first then the size of the file is extended, never the other

543 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that

544 ** information is written to disk in the same order as calls

545 ** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that

546 ** after reboot following a crash or power loss, the only bytes in a

547 ** file that were written at the application level might have changed

548 ** and that adjacent bytes, even bytes within the same sector are

549 ** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN

550 ** flag indicate that a file cannot be deleted when open. The

551 ** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on

552 ** read-only media and cannot be changed even by processes with

553 ** elevated privileges.

554 */

555 #define SQLITE_IOCAP_ATOMIC 0x00000001

556 #define SQLITE_IOCAP_ATOMIC512 0x00000002

557 #define SQLITE_IOCAP_ATOMIC1K 0x00000004

558 #define SQLITE_IOCAP_ATOMIC2K 0x00000008

559 #define SQLITE_IOCAP_ATOMIC4K 0x00000010

560 #define SQLITE_IOCAP_ATOMIC8K 0x00000020

561 #define SQLITE_IOCAP_ATOMIC16K 0x00000040

562 #define SQLITE_IOCAP_ATOMIC32K 0x00000080

563 #define SQLITE_IOCAP_ATOMIC64K 0x00000100

564 #define SQLITE_IOCAP_SAFE_APPEND 0x00000200

565 #define SQLITE_IOCAP_SEQUENTIAL 0x00000400

566 #define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800

567 #define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000

568 #define SQLITE_IOCAP_IMMUTABLE 0x00002000

569

570 /*

571 ** CAPI3REF: File Locking Levels

572 **

573 ** SQLite uses one of these integer values as the second

574 ** argument to calls it makes to the xLock() and xUnlock() methods

575 ** of an [sqlite3_io_methods] object.

576 */

577 #define SQLITE_LOCK_NONE 0

578 #define SQLITE_LOCK_SHARED 1

579 #define SQLITE_LOCK_RESERVED 2

580 #define SQLITE_LOCK_PENDING 3

581 #define SQLITE_LOCK_EXCLUSIVE 4

582

583 /*

584 ** CAPI3REF: Synchronization Type Flags

585 **

586 ** When SQLite invokes the xSync() method of an

587 ** [sqlite3_io_methods] object it uses a combination of

588 ** these integer values as the second argument.

589 **

590 ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the

591 ** sync operation only needs to flush data to mass storage. Inode

592 ** information need not be flushed. If the lower four bits of the flag

593 ** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.

594 ** If the lower four bits equal SQLITE_SYNC_FULL, that means

595 ** to use Mac OS X style fullsync instead of fsync().

596 **

597 ** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags

598 ** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL

599 ** settings. The [synchronous pragma] determines when calls to the

600 ** xSync VFS method occur and applies uniformly across all platforms.

601 ** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how

602 ** energetic or rigorous or forceful the sync operations are and

603 ** only make a difference on Mac OSX for the default SQLite code.

604 ** (Third-party VFS implementations might also make the distinction

605 ** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the

606 ** operating systems natively supported by SQLite, only Mac OSX

607 ** cares about the difference.)

608 */

609 #define SQLITE_SYNC_NORMAL 0x00002

610 #define SQLITE_SYNC_FULL 0x00003

611 #define SQLITE_SYNC_DATAONLY 0x00010

612

613 /*

614 ** CAPI3REF: OS Interface Open File Handle

615 **

616 ** An [sqlite3_file] object represents an open file in the

617 ** [sqlite3_vfs \| OS interface layer]. Individual OS interface

618 ** implementations will

619 ** want to subclass this object by appending additional fields

620 ** for their own use. The pMethods entry is a pointer to an

621 ** [sqlite3_io_methods] object that defines methods for performing

622 ** I/O operations on the open file.

623 */

624 typedef struct sqlite3_file sqlite3_file;

625 struct sqlite3_file {

626 const struct sqlite3_io_methods pMethods; / Methods for an open file */

627 };

628

629 /*

630 ** CAPI3REF: OS Interface File Virtual Methods Object

631 **

632 ** Every file opened by the [sqlite3_vfs.xOpen] method populates an

633 ** [sqlite3_file] object (or, more commonly, a subclass of the

634 ** [sqlite3_file] object) with a pointer to an instance of this object.

635 ** This object defines the methods used to perform various operations

636 ** against the open file represented by the [sqlite3_file] object.

637 **

638 ** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element

639 ** to a non-NULL pointer, then the sqlite3_io_methods.xClose method

640 ** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The

641 ** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]

642 ** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element

643 ** to NULL.

644 **

645 ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or

646 ** [SQLITE_SYNC_FULL]. The first choice is the normal fsync().

647 ** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY]

648 ** flag may be ORed in to indicate that only the data of the file

649 ** and not its inode needs to be synced.

650 **

651 ** The integer values to xLock() and xUnlock() are one of

652 ** <ul>

653 ** <li> [SQLITE_LOCK_NONE],

654 ** <li> [SQLITE_LOCK_SHARED],

655 ** <li> [SQLITE_LOCK_RESERVED],

656 ** <li> [SQLITE_LOCK_PENDING], or

657 ** <li> [SQLITE_LOCK_EXCLUSIVE].

658 ** </ul>

659 ** xLock() increases the lock. xUnlock() decreases the lock.

660 ** The xCheckReservedLock() method checks whether any database connection,

661 ** either in this process or in some other process, is holding a RESERVED,

662 ** PENDING, or EXCLUSIVE lock on the file. It returns true

663 ** if such a lock exists and false otherwise.

664 **

665 ** The xFileControl() method is a generic interface that allows custom

666 ** VFS implementations to directly control an open file using the

667 ** [sqlite3_file_control()] interface. The second "op" argument is an

668 ** integer opcode. The third argument is a generic pointer intended to

669 ** point to a structure that may contain arguments or space in which to

670 ** write return values. Potential uses for xFileControl() might be

671 ** functions to enable blocking locks with timeouts, to change the

672 ** locking strategy (for example to use dot-file locks), to inquire

673 ** about the status of a lock, or to break stale locks. The SQLite

674 ** core reserves all opcodes less than 100 for its own use.

675 ** A [file control opcodes \| list of opcodes] less than 100 is available.

676 ** Applications that define a custom xFileControl method should use opcodes

677 ** greater than 100 to avoid conflicts. VFS implementations should

678 ** return [SQLITE_NOTFOUND] for file control opcodes that they do not

679 ** recognize.

680 **

681 ** The xSectorSize() method returns the sector size of the

682 ** device that underlies the file. The sector size is the

683 ** minimum write that can be performed without disturbing

684 ** other bytes in the file. The xDeviceCharacteristics()

685 ** method returns a bit vector describing behaviors of the

686 ** underlying device:

687 **

688 ** <ul>

689 ** <li> [SQLITE_IOCAP_ATOMIC]

690 ** <li> [SQLITE_IOCAP_ATOMIC512]

691 ** <li> [SQLITE_IOCAP_ATOMIC1K]

692 ** <li> [SQLITE_IOCAP_ATOMIC2K]

693 ** <li> [SQLITE_IOCAP_ATOMIC4K]

694 ** <li> [SQLITE_IOCAP_ATOMIC8K]

695 ** <li> [SQLITE_IOCAP_ATOMIC16K]

696 ** <li> [SQLITE_IOCAP_ATOMIC32K]

697 ** <li> [SQLITE_IOCAP_ATOMIC64K]

698 ** <li> [SQLITE_IOCAP_SAFE_APPEND]

699 ** <li> [SQLITE_IOCAP_SEQUENTIAL]

700 ** </ul>

701 **

702 ** The SQLITE_IOCAP_ATOMIC property means that all writes of

703 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values

704 ** mean that writes of blocks that are nnn bytes in size and

705 ** are aligned to an address which is an integer multiple of

706 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means

707 ** that when data is appended to a file, the data is appended

708 ** first then the size of the file is extended, never the other

709 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that

710 ** information is written to disk in the same order as calls

711 ** to xWrite().

712 **

713 ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill

714 ** in the unread portions of the buffer with zeros. A VFS that

715 ** fails to zero-fill short reads might seem to work. However,

716 ** failure to zero-fill short reads will eventually lead to

717 ** database corruption.

718 */

719 typedef struct sqlite3_io_methods sqlite3_io_methods;

720 struct sqlite3_io_methods {

721 int iVersion;

722 int (xClose)(sqlite3_file);

723 int (xRead)(sqlite3_file, void*, int iAmt, sqlite3_int64 iOfst);

724 int (xWrite)(sqlite3_file, const void*, int iAmt, sqlite3_int64 iOfst);

725 int (xTruncate)(sqlite3_file, sqlite3_int64 size);

726 int (xSync)(sqlite3_file, int flags);

727 int (xFileSize)(sqlite3_file, sqlite3_int64 *pSize);

728 int (xLock)(sqlite3_file, int);

729 int (xUnlock)(sqlite3_file, int);

730 int (xCheckReservedLock)(sqlite3_file, int *pResOut);

731 int (xFileControl)(sqlite3_file, int op, void *pArg);

732 int (xSectorSize)(sqlite3_file);

733 int (xDeviceCharacteristics)(sqlite3_file);

734 /* Methods above are valid for version 1 */

735 int (xShmMap)(sqlite3_file, int iPg, int pgsz, int, void volatile**);

736 int (xShmLock)(sqlite3_file, int offset, int n, int flags);

737 void (xShmBarrier)(sqlite3_file);

738 int (xShmUnmap)(sqlite3_file, int deleteFlag);

739 /* Methods above are valid for version 2 */

740 int (xFetch)(sqlite3_file, sqlite3_int64 iOfst, int iAmt, void **pp);

741 int (xUnfetch)(sqlite3_file, sqlite3_int64 iOfst, void *p);

742 /* Methods above are valid for version 3 */

743 /* Additional methods may be added in future releases */

744 };

745

746 /*

747 ** CAPI3REF: Standard File Control Opcodes

748 ** KEYWORDS: {file control opcodes} {file control opcode}

749 **

750 ** These integer constants are opcodes for the xFileControl method

751 ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]

752 ** interface.

753 **

754 ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This

755 ** opcode causes the xFileControl method to write the current state of

756 ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],

757 ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])

758 ** into an integer that the pArg argument points to. This capability

759 ** is used during testing and only needs to be supported when SQLITE_TEST

760 ** is defined.

761 ** <ul>

762 ** <li>[[SQLITE_FCNTL_SIZE_HINT]]

763 ** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS

764 ** layer a hint of how large the database file will grow to be during the

765 ** current transaction. This hint is not guaranteed to be accurate but it

766 ** is often close. The underlying VFS might choose to preallocate database

767 ** file space based on this hint in order to help writes to the database

768 ** file run faster.

769 **

770 ** <li>[[SQLITE_FCNTL_CHUNK_SIZE]]

771 ** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS

772 ** extends and truncates the database file in chunks of a size specified

773 ** by the user. The fourth argument to [sqlite3_file_control()] should

774 ** point to an integer (type int) containing the new chunk-size to use

775 ** for the nominated database. Allocating database file space in large

776 ** chunks (say 1MB at a time), may reduce file-system fragmentation and

777 ** improve performance on some systems.

778 **

779 ** <li>[[SQLITE_FCNTL_FILE_POINTER]]

780 ** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer

781 ** to the [sqlite3_file] object associated with a particular database

782 ** connection. See the [sqlite3_file_control()] documentation for

783 ** additional information.

784 **

785 ** <li>[[SQLITE_FCNTL_SYNC_OMITTED]]

786 ** No longer in use.

787 **

788 ** <li>[[SQLITE_FCNTL_SYNC]]

789 ** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and

790 ** sent to the VFS immediately before the xSync method is invoked on a

791 ** database file descriptor. Or, if the xSync method is not invoked

792 ** because the user has configured SQLite with

793 ** [PRAGMA synchronous \| PRAGMA synchronous=OFF] it is invoked in place

794 ** of the xSync method. In most cases, the pointer argument passed with

795 ** this file-control is NULL. However, if the database file is being synced

796 ** as part of a multi-database commit, the argument points to a nul-terminated

797 ** string containing the transactions master-journal file name. VFSes that

798 ** do not need this signal should silently ignore this opcode. Applications

799 ** should not call [sqlite3_file_control()] with this opcode as doing so may

800 ** disrupt the operation of the specialized VFSes that do require it.

801 **

802 ** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]]

803 ** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite

804 ** and sent to the VFS after a transaction has been committed immediately

805 ** but before the database is unlocked. VFSes that do not need this signal

806 ** should silently ignore this opcode. Applications should not call

807 ** [sqlite3_file_control()] with this opcode as doing so may disrupt the

808 ** operation of the specialized VFSes that do require it.

809 **

810 ** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]]

811 ** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic

812 ** retry counts and intervals for certain disk I/O operations for the

813 ** windows [VFS] in order to provide robustness in the presence of

814 ** anti-virus programs. By default, the windows VFS will retry file read,

815 ** file write, and file delete operations up to 10 times, with a delay

816 ** of 25 milliseconds before the first retry and with the delay increasing

817 ** by an additional 25 milliseconds with each subsequent retry. This

818 ** opcode allows these two values (10 retries and 25 milliseconds of delay)

819 ** to be adjusted. The values are changed for all database connections

820 ** within the same process. The argument is a pointer to an array of two

821 ** integers where the first integer i the new retry count and the second

822 ** integer is the delay. If either integer is negative, then the setting

823 ** is not changed but instead the prior value of that setting is written

824 ** into the array entry, allowing the current retry settings to be

825 ** interrogated. The zDbName parameter is ignored.

826 **

827 ** <li>[[SQLITE_FCNTL_PERSIST_WAL]]

828 ** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the

829 ** persistent [WAL \| Write Ahead Log] setting. By default, the auxiliary

830 ** write ahead log and shared memory files used for transaction control

831 ** are automatically deleted when the latest connection to the database

832 ** closes. Setting persistent WAL mode causes those files to persist after

833 ** close. Persisting the files is useful when other processes that do not

834 ** have write permission on the directory containing the database file want

835 ** to read the database file, as the WAL and shared memory files must exist

836 ** in order for the database to be readable. The fourth parameter to

837 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.

838 ** That integer is 0 to disable persistent WAL mode or 1 to enable persistent

839 ** WAL mode. If the integer is -1, then it is overwritten with the current

840 ** WAL persistence setting.

841 **

842 ** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]]

843 ** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the

844 ** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting

845 ** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the

846 ** xDeviceCharacteristics methods. The fourth parameter to

847 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.

848 ** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage

849 ** mode. If the integer is -1, then it is overwritten with the current

850 ** zero-damage mode setting.

851 **

852 ** <li>[[SQLITE_FCNTL_OVERWRITE]]

853 ** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening

854 ** a write transaction to indicate that, unless it is rolled back for some

855 ** reason, the entire database file will be overwritten by the current

856 ** transaction. This is used by VACUUM operations.

857 **

858 ** <li>[[SQLITE_FCNTL_VFSNAME]]

859 ** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of

860 ** all [VFSes] in the VFS stack. The names are of all VFS shims and the

861 ** final bottom-level VFS are written into memory obtained from

862 ** [sqlite3_malloc()] and the result is stored in the char* variable

863 ** that the fourth parameter of [sqlite3_file_control()] points to.

864 ** The caller is responsible for freeing the memory when done. As with

865 ** all file-control actions, there is no guarantee that this will actually

866 ** do anything. Callers should initialize the char* variable to a NULL

867 ** pointer in case this file-control is not implemented. This file-control

868 ** is intended for diagnostic use only.

869 **

870 ** <li>[[SQLITE_FCNTL_PRAGMA]]

871 ** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA]

872 ** file control is sent to the open [sqlite3_file] object corresponding

873 ** to the database file to which the pragma statement refers. ^The argument

874 ** to the [SQLITE_FCNTL_PRAGMA] file control is an array of

875 pointers to strings (char) in which the second element of the array

876 ** is the name of the pragma and the third element is the argument to the

877 ** pragma or NULL if the pragma has no argument. ^The handler for an

878 ** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element

879 of the char argument point to a string obtained from [sqlite3_mprintf()]

880 ** or the equivalent and that string will become the result of the pragma or

881 ** the error message if the pragma fails. ^If the

882 ** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal

883 ** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA]

884 ** file control returns [SQLITE_OK], then the parser assumes that the

885 ** VFS has handled the PRAGMA itself and the parser generates a no-op

886 ** prepared statement. ^If the [SQLITE_FCNTL_PRAGMA] file control returns

887 ** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means

888 ** that the VFS encountered an error while handling the [PRAGMA] and the

889 ** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA]

890 ** file control occurs at the beginning of pragma statement analysis and so

891 ** it is able to override built-in [PRAGMA] statements.

892 **

893 ** <li>[[SQLITE_FCNTL_BUSYHANDLER]]

894 ** ^The [SQLITE_FCNTL_BUSYHANDLER]

895 ** file-control may be invoked by SQLite on the database file handle

896 ** shortly after it is opened in order to provide a custom VFS with access

897 to the connections busy-handler callback. The argument is of type (void )

898 ** - an array of two (void ) values. The first (void ) actually points

899 ** to a function of type (int ()(void )). In order to invoke the connections

900 ** busy-handler, this function should be invoked with the second (void *) in

901 ** the array as the only argument. If it returns non-zero, then the operation

902 ** should be retried. If it returns zero, the custom VFS should abandon the

903 ** current operation.

904 **

905 ** <li>[[SQLITE_FCNTL_TEMPFILENAME]]

906 ** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control

907 ** to have SQLite generate a

908 ** temporary filename using the same algorithm that is followed to generate

909 ** temporary filenames for TEMP tables and other internal uses. The

910 argument should be a char which will be filled with the filename

911 ** written into memory obtained from [sqlite3_malloc()]. The caller should

912 ** invoke [sqlite3_free()] on the result to avoid a memory leak.

913 **

914 ** <li>[[SQLITE_FCNTL_MMAP_SIZE]]

915 ** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the

916 ** maximum number of bytes that will be used for memory-mapped I/O.

917 ** The argument is a pointer to a value of type sqlite3_int64 that

918 ** is an advisory maximum number of bytes in the file to memory map. The

919 ** pointer is overwritten with the old value. The limit is not changed if

920 ** the value originally pointed to is negative, and so the current limit

921 ** can be queried by passing in a pointer to a negative number. This

922 ** file-control is used internally to implement [PRAGMA mmap_size].

923 **

924 ** <li>[[SQLITE_FCNTL_TRACE]]

925 ** The [SQLITE_FCNTL_TRACE] file control provides advisory information

926 ** to the VFS about what the higher layers of the SQLite stack are doing.

927 ** This file control is used by some VFS activity tracing [shims].

928 ** The argument is a zero-terminated string. Higher layers in the

929 ** SQLite stack may generate instances of this file control if

930 ** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled.

931 **

932 ** <li>[[SQLITE_FCNTL_HAS_MOVED]]

933 ** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a

934 ** pointer to an integer and it writes a boolean into that integer depending

935 ** on whether or not the file has been renamed, moved, or deleted since it

936 ** was first opened.

937 **

938 ** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]]

939 ** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This

940 ** opcode causes the xFileControl method to swap the file handle with the one

941 ** pointed to by the pArg argument. This capability is used during testing

942 ** and only needs to be supported when SQLITE_TEST is defined.

943 **

944 ** </ul>

945 */

946 #define SQLITE_FCNTL_LOCKSTATE 1

947 #define SQLITE_GET_LOCKPROXYFILE 2

948 #define SQLITE_SET_LOCKPROXYFILE 3

949 #define SQLITE_LAST_ERRNO 4

950 #define SQLITE_FCNTL_SIZE_HINT 5

951 #define SQLITE_FCNTL_CHUNK_SIZE 6

952 #define SQLITE_FCNTL_FILE_POINTER 7

953 #define SQLITE_FCNTL_SYNC_OMITTED 8

954 #define SQLITE_FCNTL_WIN32_AV_RETRY 9

955 #define SQLITE_FCNTL_PERSIST_WAL 10

956 #define SQLITE_FCNTL_OVERWRITE 11

957 #define SQLITE_FCNTL_VFSNAME 12

958 #define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13

959 #define SQLITE_FCNTL_PRAGMA 14

960 #define SQLITE_FCNTL_BUSYHANDLER 15

961 #define SQLITE_FCNTL_TEMPFILENAME 16

962 #define SQLITE_FCNTL_MMAP_SIZE 18

963 #define SQLITE_FCNTL_TRACE 19

964 #define SQLITE_FCNTL_HAS_MOVED 20

965 #define SQLITE_FCNTL_SYNC 21

966 #define SQLITE_FCNTL_COMMIT_PHASETWO 22

967 #define SQLITE_FCNTL_WIN32_SET_HANDLE 23

968

969 /*

970 ** CAPI3REF: Mutex Handle

971 **

972 ** The mutex module within SQLite defines [sqlite3_mutex] to be an

973 ** abstract type for a mutex object. The SQLite core never looks

974 ** at the internal representation of an [sqlite3_mutex]. It only

975 ** deals with pointers to the [sqlite3_mutex] object.

976 **

977 ** Mutexes are created using [sqlite3_mutex_alloc()].

978 */

979 typedef struct sqlite3_mutex sqlite3_mutex;

980

981 /*

982 ** CAPI3REF: OS Interface Object

983 **

984 ** An instance of the sqlite3_vfs object defines the interface between

985 ** the SQLite core and the underlying operating system. The "vfs"

986 ** in the name of the object stands for "virtual file system". See

987 ** the [VFS \| VFS documentation] for further information.

988 **

989 ** The value of the iVersion field is initially 1 but may be larger in

990 ** future versions of SQLite. Additional fields may be appended to this

991 ** object when the iVersion value is increased. Note that the structure

992 ** of the sqlite3_vfs object changes in the transaction between

993 ** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not

994 ** modified.

995 **

996 ** The szOsFile field is the size of the subclassed [sqlite3_file]

997 ** structure used by this VFS. mxPathname is the maximum length of

998 ** a pathname in this VFS.

999 **

1000 ** Registered sqlite3_vfs objects are kept on a linked list formed by

1001 ** the pNext pointer. The [sqlite3_vfs_register()]

1002 ** and [sqlite3_vfs_unregister()] interfaces manage this list

1003 ** in a thread-safe way. The [sqlite3_vfs_find()] interface

1004 ** searches the list. Neither the application code nor the VFS

1005 ** implementation should use the pNext pointer.

1006 **

1007 ** The pNext field is the only field in the sqlite3_vfs

1008 ** structure that SQLite will ever modify. SQLite will only access

1009 ** or modify this field while holding a particular static mutex.

1010 ** The application should never modify anything within the sqlite3_vfs

1011 ** object once the object has been registered.

1012 **

1013 ** The zName field holds the name of the VFS module. The name must

1014 ** be unique across all VFS modules.

1015 **

1016 ** [[sqlite3_vfs.xOpen]]

1017 ** ^SQLite guarantees that the zFilename parameter to xOpen

1018 ** is either a NULL pointer or string obtained

1019 ** from xFullPathname() with an optional suffix added.

1020 ** ^If a suffix is added to the zFilename parameter, it will

1021 ** consist of a single "-" character followed by no more than

1022 ** 11 alphanumeric and/or "-" characters.

1023 ** ^SQLite further guarantees that

1024 ** the string will be valid and unchanged until xClose() is

1025 ** called. Because of the previous sentence,

1026 ** the [sqlite3_file] can safely store a pointer to the

1027 ** filename if it needs to remember the filename for some reason.

1028 ** If the zFilename parameter to xOpen is a NULL pointer then xOpen

1029 ** must invent its own temporary name for the file. ^Whenever the

1030 ** xFilename parameter is NULL it will also be the case that the

1031 ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].

1032 **

1033 ** The flags argument to xOpen() includes all bits set in

1034 ** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()]

1035 ** or [sqlite3_open16()] is used, then flags includes at least

1036 ** [SQLITE_OPEN_READWRITE] \| [SQLITE_OPEN_CREATE].

1037 ** If xOpen() opens a file read-only then it sets *pOutFlags to

1038 ** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set.

1039 **

1040 ** ^(SQLite will also add one of the following flags to the xOpen()

1041 ** call, depending on the object being opened:

1042 **

1043 ** <ul>

1044 ** <li> [SQLITE_OPEN_MAIN_DB]

1045 ** <li> [SQLITE_OPEN_MAIN_JOURNAL]

1046 ** <li> [SQLITE_OPEN_TEMP_DB]

1047 ** <li> [SQLITE_OPEN_TEMP_JOURNAL]

1048 ** <li> [SQLITE_OPEN_TRANSIENT_DB]

1049 ** <li> [SQLITE_OPEN_SUBJOURNAL]

1050 ** <li> [SQLITE_OPEN_MASTER_JOURNAL]

1051 ** <li> [SQLITE_OPEN_WAL]

1052 ** </ul>)^

1053 **

1054 ** The file I/O implementation can use the object type flags to

1055 ** change the way it deals with files. For example, an application

1056 ** that does not care about crash recovery or rollback might make

1057 ** the open of a journal file a no-op. Writes to this journal would

1058 ** also be no-ops, and any attempt to read the journal would return

1059 ** SQLITE_IOERR. Or the implementation might recognize that a database

1060 ** file will be doing page-aligned sector reads and writes in a random

1061 ** order and set up its I/O subsystem accordingly.

1062 **

1063 ** SQLite might also add one of the following flags to the xOpen method:

1064 **

1065 ** <ul>

1066 ** <li> [SQLITE_OPEN_DELETEONCLOSE]

1067 ** <li> [SQLITE_OPEN_EXCLUSIVE]

1068 ** </ul>

1069 **

1070 ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be

1071 ** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE]

1072 ** will be set for TEMP databases and their journals, transient

1073 ** databases, and subjournals.

1074 **

1075 ** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction

1076 ** with the [SQLITE_OPEN_CREATE] flag, which are both directly

1077 ** analogous to the O_EXCL and O_CREAT flags of the POSIX open()

1078 ** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the

1079 ** SQLITE_OPEN_CREATE, is used to indicate that file should always

1080 ** be created, and that it is an error if it already exists.

1081 ** It is <i>not</i> used to indicate the file should be opened

1082 ** for exclusive access.

1083 **

1084 ** ^At least szOsFile bytes of memory are allocated by SQLite

1085 ** to hold the [sqlite3_file] structure passed as the third

1086 ** argument to xOpen. The xOpen method does not have to

1087 ** allocate the structure; it should just fill it in. Note that

1088 ** the xOpen method must set the sqlite3_file.pMethods to either

1089 ** a valid [sqlite3_io_methods] object or to NULL. xOpen must do

1090 ** this even if the open fails. SQLite expects that the sqlite3_file.pMethods

1091 ** element will be valid after xOpen returns regardless of the success

1092 ** or failure of the xOpen call.

1093 **

1094 ** [[sqlite3_vfs.xAccess]]

1095 ** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]

1096 ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to

1097 ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]

1098 ** to test whether a file is at least readable. The file can be a

1099 ** directory.

1100 **

1101 ** ^SQLite will always allocate at least mxPathname+1 bytes for the

1102 ** output buffer xFullPathname. The exact size of the output buffer

1103 ** is also passed as a parameter to both methods. If the output buffer

1104 ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is

1105 ** handled as a fatal error by SQLite, vfs implementations should endeavor

1106 ** to prevent this by setting mxPathname to a sufficiently large value.

1107 **

1108 ** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()

1109 ** interfaces are not strictly a part of the filesystem, but they are

1110 ** included in the VFS structure for completeness.

1111 ** The xRandomness() function attempts to return nBytes bytes

1112 ** of good-quality randomness into zOut. The return value is

1113 ** the actual number of bytes of randomness obtained.

1114 ** The xSleep() method causes the calling thread to sleep for at

1115 ** least the number of microseconds given. ^The xCurrentTime()

1116 ** method returns a Julian Day Number for the current date and time as

1117 ** a floating point value.

1118 ** ^The xCurrentTimeInt64() method returns, as an integer, the Julian

1119 ** Day Number multiplied by 86400000 (the number of milliseconds in

1120 ** a 24-hour day).

1121 ** ^SQLite will use the xCurrentTimeInt64() method to get the current

1122 ** date and time if that method is available (if iVersion is 2 or

1123 ** greater and the function pointer is not NULL) and will fall back

1124 ** to xCurrentTime() if xCurrentTimeInt64() is unavailable.

1125 **

1126 ** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces

1127 ** are not used by the SQLite core. These optional interfaces are provided

1128 ** by some VFSes to facilitate testing of the VFS code. By overriding

1129 ** system calls with functions under its control, a test program can

1130 ** simulate faults and error conditions that would otherwise be difficult

1131 ** or impossible to induce. The set of system calls that can be overridden

1132 ** varies from one VFS to another, and from one version of the same VFS to the

1133 ** next. Applications that use these interfaces must be prepared for any

1134 ** or all of these interfaces to be NULL or for their behavior to change

1135 ** from one release to the next. Applications must not attempt to access

1136 ** any of these methods if the iVersion of the VFS is less than 3.

1137 */

1138 typedef struct sqlite3_vfs sqlite3_vfs;

1139 typedef void (*sqlite3_syscall_ptr)(void);

1140 struct sqlite3_vfs {

1141 int iVersion; /* Structure version number (currently 3) */

1142 int szOsFile; /* Size of subclassed sqlite3_file */

1143 int mxPathname; /* Maximum file pathname length */

1144 sqlite3_vfs pNext; / Next registered VFS */

1145 const char zName; / Name of this virtual file system */

1146 void pAppData; / Pointer to application-specific data */

1147 int (xOpen)(sqlite3_vfs, const char zName, sqlite3_file,

1148 int flags, int *pOutFlags);

1149 int (xDelete)(sqlite3_vfs, const char *zName, int syncDir);

1150 int (xAccess)(sqlite3_vfs, const char zName, int flags, int pResOut);

1151 int (xFullPathname)(sqlite3_vfs, const char zName, int nOut, char zOut);

1152 void (xDlOpen)(sqlite3_vfs, const char zFilename);

1153 void (xDlError)(sqlite3_vfs, int nByte, char *zErrMsg);

1154 void ((xDlSym)(sqlite3_vfs,void, const char *zSymbol))(void);

1155 void (xDlClose)(sqlite3_vfs, void*);

1156 int (xRandomness)(sqlite3_vfs, int nByte, char *zOut);

1157 int (xSleep)(sqlite3_vfs, int microseconds);

1158 int (xCurrentTime)(sqlite3_vfs, double*);

1159 int (xGetLastError)(sqlite3_vfs, int, char *);

1160 /*

1161 ** The methods above are in version 1 of the sqlite_vfs object

1162 ** definition. Those that follow are added in version 2 or later

1163 */

1164 int (xCurrentTimeInt64)(sqlite3_vfs, sqlite3_int64*);

1165 /*

1166 ** The methods above are in versions 1 and 2 of the sqlite_vfs object.

1167 ** Those below are for version 3 and greater.

1168 */

1169 int (xSetSystemCall)(sqlite3_vfs, const char *zName, sqlite3_syscall_ptr);

1170 sqlite3_syscall_ptr (xGetSystemCall)(sqlite3_vfs, const char *zName);

1171 const char (xNextSystemCall)(sqlite3_vfs, const char zName);

1172 /*

1173 ** The methods above are in versions 1 through 3 of the sqlite_vfs object.

1174 ** New fields may be appended in figure versions. The iVersion

1175 ** value will increment whenever this happens.

1176 */

1177 };

1178

1179 /*

1180 ** CAPI3REF: Flags for the xAccess VFS method

1181 **

1182 ** These integer constants can be used as the third parameter to

1183 ** the xAccess method of an [sqlite3_vfs] object. They determine

1184 ** what kind of permissions the xAccess method is looking for.

1185 ** With SQLITE_ACCESS_EXISTS, the xAccess method

1186 ** simply checks whether the file exists.

1187 ** With SQLITE_ACCESS_READWRITE, the xAccess method

1188 ** checks whether the named directory is both readable and writable

1189 ** (in other words, if files can be added, removed, and renamed within

1190 ** the directory).

1191 ** The SQLITE_ACCESS_READWRITE constant is currently used only by the

1192 ** [temp_store_directory pragma], though this could change in a future

1193 ** release of SQLite.

1194 ** With SQLITE_ACCESS_READ, the xAccess method

1195 ** checks whether the file is readable. The SQLITE_ACCESS_READ constant is

1196 ** currently unused, though it might be used in a future release of

1197 ** SQLite.

1198 */

1199 #define SQLITE_ACCESS_EXISTS 0

1200 #define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */

1201 #define SQLITE_ACCESS_READ 2 /* Unused */

1202

1203 /*

1204 ** CAPI3REF: Flags for the xShmLock VFS method

1205 **

1206 ** These integer constants define the various locking operations

1207 ** allowed by the xShmLock method of [sqlite3_io_methods]. The

1208 ** following are the only legal combinations of flags to the

1209 ** xShmLock method:

1210 **

1211 ** <ul>

1212 ** <li> SQLITE_SHM_LOCK \| SQLITE_SHM_SHARED

1213 ** <li> SQLITE_SHM_LOCK \| SQLITE_SHM_EXCLUSIVE

1214 ** <li> SQLITE_SHM_UNLOCK \| SQLITE_SHM_SHARED

1215 ** <li> SQLITE_SHM_UNLOCK \| SQLITE_SHM_EXCLUSIVE

1216 ** </ul>

1217 **

1218 ** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as

1219 ** was given no the corresponding lock.

1220 **

1221 ** The xShmLock method can transition between unlocked and SHARED or

1222 ** between unlocked and EXCLUSIVE. It cannot transition between SHARED

1223 ** and EXCLUSIVE.

1224 */

1225 #define SQLITE_SHM_UNLOCK 1

1226 #define SQLITE_SHM_LOCK 2

1227 #define SQLITE_SHM_SHARED 4

1228 #define SQLITE_SHM_EXCLUSIVE 8

1229

1230 /*

1231 ** CAPI3REF: Maximum xShmLock index

1232 **

1233 ** The xShmLock method on [sqlite3_io_methods] may use values

1234 ** between 0 and this upper bound as its "offset" argument.

1235 ** The SQLite core will never attempt to acquire or release a

1236 ** lock outside of this range

1237 */

1238 #define SQLITE_SHM_NLOCK 8

1239

1240

1241 /*

1242 ** CAPI3REF: Initialize The SQLite Library

1243 **

1244 ** ^The sqlite3_initialize() routine initializes the

1245 ** SQLite library. ^The sqlite3_shutdown() routine

1246 ** deallocates any resources that were allocated by sqlite3_initialize().

1247 ** These routines are designed to aid in process initialization and

1248 ** shutdown on embedded systems. Workstation applications using

1249 ** SQLite normally do not need to invoke either of these routines.

1250 **

1251 ** A call to sqlite3_initialize() is an "effective" call if it is

1252 ** the first time sqlite3_initialize() is invoked during the lifetime of

1253 ** the process, or if it is the first time sqlite3_initialize() is invoked

1254 ** following a call to sqlite3_shutdown(). ^(Only an effective call

1255 ** of sqlite3_initialize() does any initialization. All other calls

1256 ** are harmless no-ops.)^

1257 **

1258 ** A call to sqlite3_shutdown() is an "effective" call if it is the first

1259 ** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only

1260 ** an effective call to sqlite3_shutdown() does any deinitialization.

1261 ** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^

1262 **

1263 ** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()

1264 ** is not. The sqlite3_shutdown() interface must only be called from a

1265 ** single thread. All open [database connections] must be closed and all

1266 ** other SQLite resources must be deallocated prior to invoking

1267 ** sqlite3_shutdown().

1268 **

1269 ** Among other things, ^sqlite3_initialize() will invoke

1270 ** sqlite3_os_init(). Similarly, ^sqlite3_shutdown()

1271 ** will invoke sqlite3_os_end().

1272 **

1273 ** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.

1274 ** ^If for some reason, sqlite3_initialize() is unable to initialize

1275 ** the library (perhaps it is unable to allocate a needed resource such

1276 ** as a mutex) it returns an [error code] other than [SQLITE_OK].

1277 **

1278 ** ^The sqlite3_initialize() routine is called internally by many other

1279 ** SQLite interfaces so that an application usually does not need to

1280 ** invoke sqlite3_initialize() directly. For example, [sqlite3_open()]

1281 ** calls sqlite3_initialize() so the SQLite library will be automatically

1282 ** initialized when [sqlite3_open()] is called if it has not be initialized

1283 ** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]

1284 ** compile-time option, then the automatic calls to sqlite3_initialize()

1285 ** are omitted and the application must call sqlite3_initialize() directly

1286 ** prior to using any other SQLite interface. For maximum portability,

1287 ** it is recommended that applications always invoke sqlite3_initialize()

1288 ** directly prior to using any other SQLite interface. Future releases

1289 ** of SQLite may require this. In other words, the behavior exhibited

1290 ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the

1291 ** default behavior in some future release of SQLite.

1292 **

1293 ** The sqlite3_os_init() routine does operating-system specific

1294 ** initialization of the SQLite library. The sqlite3_os_end()

1295 ** routine undoes the effect of sqlite3_os_init(). Typical tasks

1296 ** performed by these routines include allocation or deallocation

1297 ** of static resources, initialization of global variables,

1298 ** setting up a default [sqlite3_vfs] module, or setting up

1299 ** a default configuration using [sqlite3_config()].

1300 **

1301 ** The application should never invoke either sqlite3_os_init()

1302 ** or sqlite3_os_end() directly. The application should only invoke

1303 ** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init()

1304 ** interface is called automatically by sqlite3_initialize() and

1305 ** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate

1306 ** implementations for sqlite3_os_init() and sqlite3_os_end()

1307 ** are built into SQLite when it is compiled for Unix, Windows, or OS/2.

1308 ** When [custom builds \| built for other platforms]

1309 ** (using the [SQLITE_OS_OTHER=1] compile-time

1310 ** option) the application must supply a suitable implementation for

1311 ** sqlite3_os_init() and sqlite3_os_end(). An application-supplied

1312 ** implementation of sqlite3_os_init() or sqlite3_os_end()

1313 ** must return [SQLITE_OK] on success and some other [error code] upon

1314 ** failure.

1315 */

1316 int sqlite3_initialize(void);

1317 int sqlite3_shutdown(void);

1318 int sqlite3_os_init(void);

1319 int sqlite3_os_end(void);

1320

1321 /*

1322 ** CAPI3REF: Configuring The SQLite Library

1323 **

1324 ** The sqlite3_config() interface is used to make global configuration

1325 ** changes to SQLite in order to tune SQLite to the specific needs of

1326 ** the application. The default configuration is recommended for most

1327 ** applications and so this routine is usually not necessary. It is

1328 ** provided to support rare applications with unusual needs.

1329 **

1330 ** The sqlite3_config() interface is not threadsafe. The application

1331 ** must insure that no other SQLite interfaces are invoked by other

1332 ** threads while sqlite3_config() is running. Furthermore, sqlite3_config()

1333 ** may only be invoked prior to library initialization using

1334 ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].

1335 ** ^If sqlite3_config() is called after [sqlite3_initialize()] and before

1336 ** [sqlite3_shutdown()] then it will return SQLITE_MISUSE.

1337 ** Note, however, that ^sqlite3_config() can be called as part of the

1338 ** implementation of an application-defined [sqlite3_os_init()].

1339 **

1340 ** The first argument to sqlite3_config() is an integer

1341 ** [configuration option] that determines

1342 ** what property of SQLite is to be configured. Subsequent arguments

1343 ** vary depending on the [configuration option]

1344 ** in the first argument.

1345 **

1346 ** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].

1347 ** ^If the option is unknown or SQLite is unable to set the option

1348 ** then this routine returns a non-zero [error code].

1349 */

1350 int sqlite3_config(int, ...);

1351

1352 /*

1353 ** CAPI3REF: Configure database connections

1354 **

1355 ** The sqlite3_db_config() interface is used to make configuration

1356 ** changes to a [database connection]. The interface is similar to

1357 ** [sqlite3_config()] except that the changes apply to a single

1358 ** [database connection] (specified in the first argument).

1359 **

1360 ** The second argument to sqlite3_db_config(D,V,...) is the

1361 ** [SQLITE_DBCONFIG_LOOKASIDE \| configuration verb] - an integer code

1362 ** that indicates what aspect of the [database connection] is being configured.

1363 ** Subsequent arguments vary depending on the configuration verb.

1364 **

1365 ** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if

1366 ** the call is considered successful.

1367 */

1368 int sqlite3_db_config(sqlite3*, int op, ...);

1369

1370 /*

1371 ** CAPI3REF: Memory Allocation Routines

1372 **

1373 ** An instance of this object defines the interface between SQLite

1374 ** and low-level memory allocation routines.

1375 **

1376 ** This object is used in only one place in the SQLite interface.

1377 ** A pointer to an instance of this object is the argument to

1378 ** [sqlite3_config()] when the configuration option is

1379 ** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].

1380 ** By creating an instance of this object

1381 ** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])

1382 ** during configuration, an application can specify an alternative

1383 ** memory allocation subsystem for SQLite to use for all of its

1384 ** dynamic memory needs.

1385 **

1386 ** Note that SQLite comes with several [built-in memory allocators]

1387 ** that are perfectly adequate for the overwhelming majority of applications

1388 ** and that this object is only useful to a tiny minority of applications

1389 ** with specialized memory allocation requirements. This object is

1390 ** also used during testing of SQLite in order to specify an alternative

1391 ** memory allocator that simulates memory out-of-memory conditions in

1392 ** order to verify that SQLite recovers gracefully from such

1393 ** conditions.

1394 **

1395 ** The xMalloc, xRealloc, and xFree methods must work like the

1396 ** malloc(), realloc() and free() functions from the standard C library.

1397 ** ^SQLite guarantees that the second argument to

1398 ** xRealloc is always a value returned by a prior call to xRoundup.

1399 **

1400 ** xSize should return the allocated size of a memory allocation

1401 ** previously obtained from xMalloc or xRealloc. The allocated size

1402 ** is always at least as big as the requested size but may be larger.

1403 **

1404 ** The xRoundup method returns what would be the allocated size of

1405 ** a memory allocation given a particular requested size. Most memory

1406 ** allocators round up memory allocations at least to the next multiple

1407 ** of 8. Some allocators round up to a larger multiple or to a power of 2.

1408 ** Every memory allocation request coming in through [sqlite3_malloc()]

1409 ** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0,

1410 ** that causes the corresponding memory allocation to fail.

1411 **

1412 ** The xInit method initializes the memory allocator. For example,

1413 ** it might allocate any require mutexes or initialize internal data

1414 ** structures. The xShutdown method is invoked (indirectly) by

1415 ** [sqlite3_shutdown()] and should deallocate any resources acquired

1416 ** by xInit. The pAppData pointer is used as the only parameter to

1417 ** xInit and xShutdown.

1418 **

1419 ** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes

1420 ** the xInit method, so the xInit method need not be threadsafe. The

1421 ** xShutdown method is only called from [sqlite3_shutdown()] so it does

1422 ** not need to be threadsafe either. For all other methods, SQLite

1423 ** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the

1424 ** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which

1425 ** it is by default) and so the methods are automatically serialized.

1426 ** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other

1427 ** methods must be threadsafe or else make their own arrangements for

1428 ** serialization.

1429 **

1430 ** SQLite will never invoke xInit() more than once without an intervening

1431 ** call to xShutdown().

1432 */

1433 typedef struct sqlite3_mem_methods sqlite3_mem_methods;

1434 struct sqlite3_mem_methods {

1435 void (xMalloc)(int); /* Memory allocation function */

1436 void (xFree)(void); /* Free a prior allocation */

1437 void (xRealloc)(void,int); / Resize an allocation */

1438 int (xSize)(void); /* Return the size of an allocation */

1439 int (xRoundup)(int); / Round up request size to allocation size */

1440 int (xInit)(void); /* Initialize the memory allocator */

1441 void (xShutdown)(void); /* Deinitialize the memory allocator */

1442 void pAppData; / Argument to xInit() and xShutdown() */

1443 };

1444

1445 /*

1446 ** CAPI3REF: Configuration Options

1447 ** KEYWORDS: {configuration option}

1448 **

1449 ** These constants are the available integer configuration options that

1450 ** can be passed as the first argument to the [sqlite3_config()] interface.

1451 **

1452 ** New configuration options may be added in future releases of SQLite.

1453 ** Existing configuration options might be discontinued. Applications

1454 ** should check the return code from [sqlite3_config()] to make sure that

1455 ** the call worked. The [sqlite3_config()] interface will return a

1456 ** non-zero [error code] if a discontinued or unsupported configuration option

1457 ** is invoked.

1458 **

1459 ** <dl>

1460 ** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt>

1461 ** <dd>There are no arguments to this option. ^This option sets the

1462 ** [threading mode] to Single-thread. In other words, it disables

1463 ** all mutexing and puts SQLite into a mode where it can only be used

1464 ** by a single thread. ^If SQLite is compiled with

1465 ** the [SQLITE_THREADSAFE \| SQLITE_THREADSAFE=0] compile-time option then

1466 ** it is not possible to change the [threading mode] from its default

1467 ** value of Single-thread and so [sqlite3_config()] will return

1468 ** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD

1469 ** configuration option.</dd>

1470 **

1471 ** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt>

1472 ** <dd>There are no arguments to this option. ^This option sets the

1473 ** [threading mode] to Multi-thread. In other words, it disables

1474 ** mutexing on [database connection] and [prepared statement] objects.

1475 ** The application is responsible for serializing access to

1476 ** [database connections] and [prepared statements]. But other mutexes

1477 ** are enabled so that SQLite will be safe to use in a multi-threaded

1478 ** environment as long as no two threads attempt to use the same

1479 ** [database connection] at the same time. ^If SQLite is compiled with

1480 ** the [SQLITE_THREADSAFE \| SQLITE_THREADSAFE=0] compile-time option then

1481 ** it is not possible to set the Multi-thread [threading mode] and

1482 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the

1483 ** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>

1484 **

1485 ** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt>

1486 ** <dd>There are no arguments to this option. ^This option sets the

1487 ** [threading mode] to Serialized. In other words, this option enables

1488 ** all mutexes including the recursive

1489 ** mutexes on [database connection] and [prepared statement] objects.

1490 ** In this mode (which is the default when SQLite is compiled with

1491 ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access

1492 ** to [database connections] and [prepared statements] so that the

1493 ** application is free to use the same [database connection] or the

1494 ** same [prepared statement] in different threads at the same time.

1495 ** ^If SQLite is compiled with

1496 ** the [SQLITE_THREADSAFE \| SQLITE_THREADSAFE=0] compile-time option then

1497 ** it is not possible to set the Serialized [threading mode] and

1498 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the

1499 ** SQLITE_CONFIG_SERIALIZED configuration option.</dd>

1500 **

1501 ** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt>

1502 ** <dd> ^(This option takes a single argument which is a pointer to an

1503 ** instance of the [sqlite3_mem_methods] structure. The argument specifies

1504 ** alternative low-level memory allocation routines to be used in place of

1505 ** the memory allocation routines built into SQLite.)^ ^SQLite makes

1506 ** its own private copy of the content of the [sqlite3_mem_methods] structure

1507 ** before the [sqlite3_config()] call returns.</dd>

1508 **

1509 ** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt>

1510 ** <dd> ^(This option takes a single argument which is a pointer to an

1511 ** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods]

1512 ** structure is filled with the currently defined memory allocation routines.)^

1513 ** This option can be used to overload the default memory allocation

1514 ** routines with a wrapper that simulations memory allocation failure or

1515 ** tracks memory usage, for example. </dd>

1516 **

1517 ** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt>

1518 ** <dd> ^This option takes single argument of type int, interpreted as a

1519 ** boolean, which enables or disables the collection of memory allocation

1520 ** statistics. ^(When memory allocation statistics are disabled, the

1521 ** following SQLite interfaces become non-operational:

1522 ** <ul>

1523 ** <li> [sqlite3_memory_used()]

1524 ** <li> [sqlite3_memory_highwater()]

1525 ** <li> [sqlite3_soft_heap_limit64()]

1526 ** <li> [sqlite3_status()]

1527 ** </ul>)^

1528 ** ^Memory allocation statistics are enabled by default unless SQLite is

1529 ** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory

1530 ** allocation statistics are disabled by default.

1531 ** </dd>

1532 **

1533 ** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt>

1534 ** <dd> ^This option specifies a static memory buffer that SQLite can use for

1535 ** scratch memory. There are three arguments: A pointer an 8-byte

1536 ** aligned memory buffer from which the scratch allocations will be

1537 ** drawn, the size of each scratch allocation (sz),

1538 ** and the maximum number of scratch allocations (N). The sz

1539 ** argument must be a multiple of 16.

1540 ** The first argument must be a pointer to an 8-byte aligned buffer

1541 ** of at least sz*N bytes of memory.

1542 ** ^SQLite will use no more than two scratch buffers per thread. So

1543 ** N should be set to twice the expected maximum number of threads.

1544 ** ^SQLite will never require a scratch buffer that is more than 6

1545 ** times the database page size. ^If SQLite needs needs additional

1546 ** scratch memory beyond what is provided by this configuration option, then

1547 ** [sqlite3_malloc()] will be used to obtain the memory needed.</dd>

1548 **

1549 ** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>

1550 ** <dd> ^This option specifies a static memory buffer that SQLite can use for

1551 ** the database page cache with the default page cache implementation.

1552 ** This configuration should not be used if an application-define page

1553 ** cache implementation is loaded using the SQLITE_CONFIG_PCACHE2 option.

1554 ** There are three arguments to this option: A pointer to 8-byte aligned

1555 ** memory, the size of each page buffer (sz), and the number of pages (N).

1556 ** The sz argument should be the size of the largest database page

1557 ** (a power of two between 512 and 32768) plus a little extra for each

1558 ** page header. ^The page header size is 20 to 40 bytes depending on

1559 ** the host architecture. ^It is harmless, apart from the wasted memory,

1560 ** to make sz a little too large. The first

1561 ** argument should point to an allocation of at least sz*N bytes of memory.

1562 ** ^SQLite will use the memory provided by the first argument to satisfy its

1563 ** memory needs for the first N pages that it adds to cache. ^If additional

1564 ** page cache memory is needed beyond what is provided by this option, then

1565 ** SQLite goes to [sqlite3_malloc()] for the additional storage space.

1566 ** The pointer in the first argument must

1567 ** be aligned to an 8-byte boundary or subsequent behavior of SQLite

1568 ** will be undefined.</dd>

1569 **

1570 ** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt>

1571 ** <dd> ^This option specifies a static memory buffer that SQLite will use

1572 ** for all of its dynamic memory allocation needs beyond those provided

1573 ** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE].

1574 ** There are three arguments: An 8-byte aligned pointer to the memory,

1575 ** the number of bytes in the memory buffer, and the minimum allocation size.

1576 ** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts

1577 ** to using its default memory allocator (the system malloc() implementation),

1578 ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the

1579 ** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or

1580 ** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory

1581 ** allocator is engaged to handle all of SQLites memory allocation needs.

1582 ** The first pointer (the memory pointer) must be aligned to an 8-byte

1583 ** boundary or subsequent behavior of SQLite will be undefined.

1584 The minimum allocation size is capped at 212. Reasonable values

1585 for the minimum allocation size are 25 through 2**8.</dd>

1586 **

1587 ** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt>

1588 ** <dd> ^(This option takes a single argument which is a pointer to an

1589 ** instance of the [sqlite3_mutex_methods] structure. The argument specifies

1590 ** alternative low-level mutex routines to be used in place

1591 ** the mutex routines built into SQLite.)^ ^SQLite makes a copy of the

1592 ** content of the [sqlite3_mutex_methods] structure before the call to

1593 ** [sqlite3_config()] returns. ^If SQLite is compiled with

1594 ** the [SQLITE_THREADSAFE \| SQLITE_THREADSAFE=0] compile-time option then

1595 ** the entire mutexing subsystem is omitted from the build and hence calls to

1596 ** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will

1597 ** return [SQLITE_ERROR].</dd>

1598 **

1599 ** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt>

1600 ** <dd> ^(This option takes a single argument which is a pointer to an

1601 ** instance of the [sqlite3_mutex_methods] structure. The

1602 ** [sqlite3_mutex_methods]

1603 ** structure is filled with the currently defined mutex routines.)^

1604 ** This option can be used to overload the default mutex allocation

1605 ** routines with a wrapper used to track mutex usage for performance

1606 ** profiling or testing, for example. ^If SQLite is compiled with

1607 ** the [SQLITE_THREADSAFE \| SQLITE_THREADSAFE=0] compile-time option then

1608 ** the entire mutexing subsystem is omitted from the build and hence calls to

1609 ** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will

1610 ** return [SQLITE_ERROR].</dd>

1611 **

1612 ** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt>

1613 ** <dd> ^(This option takes two arguments that determine the default

1614 ** memory allocation for the lookaside memory allocator on each

1615 ** [database connection]. The first argument is the

1616 ** size of each lookaside buffer slot and the second is the number of

1617 ** slots allocated to each database connection.)^ ^(This option sets the

1618 ** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]

1619 ** verb to [sqlite3_db_config()] can be used to change the lookaside

1620 ** configuration on individual connections.)^ </dd>

1621 **

1622 ** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt>

1623 ** <dd> ^(This option takes a single argument which is a pointer to

1624 ** an [sqlite3_pcache_methods2] object. This object specifies the interface

1625 ** to a custom page cache implementation.)^ ^SQLite makes a copy of the

1626 ** object and uses it for page cache memory allocations.</dd>

1627 **

1628 ** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt>

1629 ** <dd> ^(This option takes a single argument which is a pointer to an

1630 ** [sqlite3_pcache_methods2] object. SQLite copies of the current

1631 ** page cache implementation into that object.)^ </dd>

1632 **

1633 ** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>

1634 ** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite

1635 ** global [error log].

1636 ** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a

1637 ** function with a call signature of void()(void,int,const char*),

1638 ** and a pointer to void. ^If the function pointer is not NULL, it is

1639 ** invoked by [sqlite3_log()] to process each logging event. ^If the

1640 ** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.

1641 ** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is

1642 ** passed through as the first parameter to the application-defined logger

1643 ** function whenever that function is invoked. ^The second parameter to

1644 ** the logger function is a copy of the first parameter to the corresponding

1645 ** [sqlite3_log()] call and is intended to be a [result code] or an

1646 ** [extended result code]. ^The third parameter passed to the logger is

1647 ** log message after formatting via [sqlite3_snprintf()].

1648 ** The SQLite logging interface is not reentrant; the logger function

1649 ** supplied by the application must not invoke any SQLite interface.

1650 ** In a multi-threaded application, the application-defined logger

1651 ** function must be threadsafe. </dd>

1652 **

1653 ** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI

1654 ** <dd>^(This option takes a single argument of type int. If non-zero, then

1655 ** URI handling is globally enabled. If the parameter is zero, then URI handling

1656 ** is globally disabled.)^ ^If URI handling is globally enabled, all filenames

1657 ** passed to [sqlite3_open()], [sqlite3_open_v2()], [sqlite3_open16()] or

1658 ** specified as part of [ATTACH] commands are interpreted as URIs, regardless

1659 ** of whether or not the [SQLITE_OPEN_URI] flag is set when the database

1660 ** connection is opened. ^If it is globally disabled, filenames are

1661 ** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the

1662 ** database connection is opened. ^(By default, URI handling is globally

1663 ** disabled. The default value may be changed by compiling with the

1664 ** [SQLITE_USE_URI] symbol defined.)^

1665 **

1666 ** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN

1667 ** <dd>^This option takes a single integer argument which is interpreted as

1668 ** a boolean in order to enable or disable the use of covering indices for

1669 ** full table scans in the query optimizer. ^The default setting is determined

1670 ** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on"

1671 ** if that compile-time option is omitted.

1672 ** The ability to disable the use of covering indices for full table scans

1673 ** is because some incorrectly coded legacy applications might malfunction

1674 ** when the optimization is enabled. Providing the ability to

1675 ** disable the optimization allows the older, buggy application code to work

1676 ** without change even with newer versions of SQLite.

1677 **

1678 ** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]]

1679 ** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE

1680 ** <dd> These options are obsolete and should not be used by new code.

1681 ** They are retained for backwards compatibility but are now no-ops.

1682 ** </dd>

1683 **

1684 ** [[SQLITE_CONFIG_SQLLOG]]

1685 ** <dt>SQLITE_CONFIG_SQLLOG

1686 ** <dd>This option is only available if sqlite is compiled with the

1687 ** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should

1688 ** be a pointer to a function of type void()(void,sqlite3,const char, int).

1689 ** The second should be of type (void*). The callback is invoked by the library

1690 ** in three separate circumstances, identified by the value passed as the

1691 ** fourth parameter. If the fourth parameter is 0, then the database connection

1692 ** passed as the second argument has just been opened. The third argument

1693 ** points to a buffer containing the name of the main database file. If the

1694 ** fourth parameter is 1, then the SQL statement that the third parameter

1695 ** points to has just been executed. Or, if the fourth parameter is 2, then

1696 ** the connection being passed as the second parameter is being closed. The

1697 ** third parameter is passed NULL In this case. An example of using this

1698 ** configuration option can be seen in the "test_sqllog.c" source file in

1699 ** the canonical SQLite source tree.</dd>

1700 **

1701 ** [[SQLITE_CONFIG_MMAP_SIZE]]

1702 ** <dt>SQLITE_CONFIG_MMAP_SIZE

1703 ** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values

1704 ** that are the default mmap size limit (the default setting for

1705 ** [PRAGMA mmap_size]) and the maximum allowed mmap size limit.

1706 ** ^The default setting can be overridden by each database connection using

1707 ** either the [PRAGMA mmap_size] command, or by using the

1708 ** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size

1709 ** cannot be changed at run-time. Nor may the maximum allowed mmap size

1710 ** exceed the compile-time maximum mmap size set by the

1711 ** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^

1712 ** ^If either argument to this option is negative, then that argument is

1713 ** changed to its compile-time default.

1714 **

1715 ** [[SQLITE_CONFIG_WIN32_HEAPSIZE]]

1716 ** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE

1717 ** <dd>^This option is only available if SQLite is compiled for Windows

1718 ** with the [SQLITE_WIN32_MALLOC] pre-processor macro defined.

1719 ** SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value

1720 ** that specifies the maximum size of the created heap.

1721 ** </dl>

1722 */

1723 #define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */

1724 #define SQLITE_CONFIG_MULTITHREAD 2 /* nil */

1725 #define SQLITE_CONFIG_SERIALIZED 3 /* nil */

1726 #define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */

1727 #define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */

1728 #define SQLITE_CONFIG_SCRATCH 6 /* void, int sz, int N /

1729 #define SQLITE_CONFIG_PAGECACHE 7 /* void, int sz, int N /

1730 #define SQLITE_CONFIG_HEAP 8 /* void, int nByte, int min /

1731 #define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */

1732 #define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */

1733 #define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */

1734 /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */

1735 #define SQLITE_CONFIG_LOOKASIDE 13 /* int int */

1736 #define SQLITE_CONFIG_PCACHE 14 /* no-op */

1737 #define SQLITE_CONFIG_GETPCACHE 15 /* no-op */

1738 #define SQLITE_CONFIG_LOG 16 /* xFunc, void* */

1739 #define SQLITE_CONFIG_URI 17 /* int */

1740 #define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */

1741 #define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */

1742 #define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */

1743 #define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */

1744 #define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */

1745 #define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */

1746

1747 /*

1748 ** CAPI3REF: Database Connection Configuration Options

1749 **

1750 ** These constants are the available integer configuration options that

1751 ** can be passed as the second argument to the [sqlite3_db_config()] interface.

1752 **

1753 ** New configuration options may be added in future releases of SQLite.

1754 ** Existing configuration options might be discontinued. Applications

1755 ** should check the return code from [sqlite3_db_config()] to make sure that

1756 ** the call worked. ^The [sqlite3_db_config()] interface will return a

1757 ** non-zero [error code] if a discontinued or unsupported configuration option

1758 ** is invoked.

1759 **

1760 ** <dl>

1761 ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>

1762 ** <dd> ^This option takes three additional arguments that determine the

1763 ** [lookaside memory allocator] configuration for the [database connection].

1764 ** ^The first argument (the third parameter to [sqlite3_db_config()] is a

1765 ** pointer to a memory buffer to use for lookaside memory.

1766 ** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb

1767 ** may be NULL in which case SQLite will allocate the

1768 ** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the

1769 ** size of each lookaside buffer slot. ^The third argument is the number of

1770 ** slots. The size of the buffer in the first argument must be greater than

1771 ** or equal to the product of the second and third arguments. The buffer

1772 ** must be aligned to an 8-byte boundary. ^If the second argument to

1773 ** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally

1774 ** rounded down to the next smaller multiple of 8. ^(The lookaside memory

1775 ** configuration for a database connection can only be changed when that

1776 ** connection is not currently using lookaside memory, or in other words

1777 ** when the "current value" returned by

1778 ** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero.

1779 ** Any attempt to change the lookaside memory configuration when lookaside

1780 ** memory is in use leaves the configuration unchanged and returns

1781 ** [SQLITE_BUSY].)^</dd>

1782 **

1783 ** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>

1784 ** <dd> ^This option is used to enable or disable the enforcement of

1785 ** [foreign key constraints]. There should be two additional arguments.

1786 ** The first argument is an integer which is 0 to disable FK enforcement,

1787 ** positive to enable FK enforcement or negative to leave FK enforcement

1788 ** unchanged. The second parameter is a pointer to an integer into which

1789 ** is written 0 or 1 to indicate whether FK enforcement is off or on

1790 ** following this call. The second parameter may be a NULL pointer, in

1791 ** which case the FK enforcement setting is not reported back. </dd>

1792 **

1793 ** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>

1794 ** <dd> ^This option is used to enable or disable [CREATE TRIGGER \| triggers].

1795 ** There should be two additional arguments.

1796 ** The first argument is an integer which is 0 to disable triggers,

1797 ** positive to enable triggers or negative to leave the setting unchanged.

1798 ** The second parameter is a pointer to an integer into which

1799 ** is written 0 or 1 to indicate whether triggers are disabled or enabled

1800 ** following this call. The second parameter may be a NULL pointer, in

1801 ** which case the trigger setting is not reported back. </dd>

1802 **

1803 ** </dl>

1804 */

1805 #define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */

1806 #define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */

1807 #define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */

1808

1809

1810 /*

1811 ** CAPI3REF: Enable Or Disable Extended Result Codes

1812 **

1813 ** ^The sqlite3_extended_result_codes() routine enables or disables the

1814 ** [extended result codes] feature of SQLite. ^The extended result

1815 ** codes are disabled by default for historical compatibility.

1816 */

1817 int sqlite3_extended_result_codes(sqlite3*, int onoff);

1818

1819 /*

1820 ** CAPI3REF: Last Insert Rowid

1821 **

1822 ** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables)

1823 ** has a unique 64-bit signed

1824 ** integer key called the [ROWID \| "rowid"]. ^The rowid is always available

1825 ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those

1826 ** names are not also used by explicitly declared columns. ^If

1827 ** the table has a column of type [INTEGER PRIMARY KEY] then that column

1828 ** is another alias for the rowid.

1829 **

1830 ** ^The sqlite3_last_insert_rowid(D) interface returns the [rowid] of the

1831 ** most recent successful [INSERT] into a rowid table or [virtual table]

1832 ** on database connection D.

1833 ** ^Inserts into [WITHOUT ROWID] tables are not recorded.

1834 ** ^If no successful [INSERT]s into rowid tables

1835 ** have ever occurred on the database connection D,

1836 ** then sqlite3_last_insert_rowid(D) returns zero.

1837 **

1838 ** ^(If an [INSERT] occurs within a trigger or within a [virtual table]

1839 ** method, then this routine will return the [rowid] of the inserted

1840 ** row as long as the trigger or virtual table method is running.

1841 ** But once the trigger or virtual table method ends, the value returned

1842 ** by this routine reverts to what it was before the trigger or virtual

1843 ** table method began.)^

1844 **

1845 ** ^An [INSERT] that fails due to a constraint violation is not a

1846 ** successful [INSERT] and does not change the value returned by this

1847 ** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,

1848 ** and INSERT OR ABORT make no changes to the return value of this

1849 ** routine when their insertion fails. ^(When INSERT OR REPLACE

1850 ** encounters a constraint violation, it does not fail. The

1851 ** INSERT continues to completion after deleting rows that caused

1852 ** the constraint problem so INSERT OR REPLACE will always change

1853 ** the return value of this interface.)^

1854 **

1855 ** ^For the purposes of this routine, an [INSERT] is considered to

1856 ** be successful even if it is subsequently rolled back.

1857 **

1858 ** This function is accessible to SQL statements via the

1859 ** [last_insert_rowid() SQL function].

1860 **

1861 ** If a separate thread performs a new [INSERT] on the same

1862 ** database connection while the [sqlite3_last_insert_rowid()]

1863 ** function is running and thus changes the last insert [rowid],

1864 ** then the value returned by [sqlite3_last_insert_rowid()] is

1865 ** unpredictable and might not equal either the old or the new

1866 ** last insert [rowid].

1867 */

1868 sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);

1869

1870 /*

1871 ** CAPI3REF: Count The Number Of Rows Modified

1872 **

1873 ** ^This function returns the number of database rows that were changed

1874 ** or inserted or deleted by the most recently completed SQL statement

1875 ** on the [database connection] specified by the first parameter.

1876 ** ^(Only changes that are directly specified by the [INSERT], [UPDATE],

1877 ** or [DELETE] statement are counted. Auxiliary changes caused by

1878 ** triggers or [foreign key actions] are not counted.)^ Use the

1879 ** [sqlite3_total_changes()] function to find the total number of changes

1880 ** including changes caused by triggers and foreign key actions.

1881 **

1882 ** ^Changes to a view that are simulated by an [INSTEAD OF trigger]

1883 ** are not counted. Only real table changes are counted.

1884 **

1885 ** ^(A "row change" is a change to a single row of a single table

1886 ** caused by an INSERT, DELETE, or UPDATE statement. Rows that

1887 ** are changed as side effects of [REPLACE] constraint resolution,

1888 ** rollback, ABORT processing, [DROP TABLE], or by any other

1889 ** mechanisms do not count as direct row changes.)^

1890 **

1891 ** A "trigger context" is a scope of execution that begins and

1892 ** ends with the script of a [CREATE TRIGGER \| trigger].

1893 ** Most SQL statements are

1894 ** evaluated outside of any trigger. This is the "top level"

1895 ** trigger context. If a trigger fires from the top level, a

1896 ** new trigger context is entered for the duration of that one

1897 ** trigger. Subtriggers create subcontexts for their duration.

1898 **

1899 ** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does

1900 ** not create a new trigger context.

1901 **

1902 ** ^This function returns the number of direct row changes in the

1903 ** most recent INSERT, UPDATE, or DELETE statement within the same

1904 ** trigger context.

1905 **

1906 ** ^Thus, when called from the top level, this function returns the

1907 ** number of changes in the most recent INSERT, UPDATE, or DELETE

1908 ** that also occurred at the top level. ^(Within the body of a trigger,

1909 ** the sqlite3_changes() interface can be called to find the number of

1910 ** changes in the most recently completed INSERT, UPDATE, or DELETE

1911 ** statement within the body of the same trigger.

1912 ** However, the number returned does not include changes

1913 ** caused by subtriggers since those have their own context.)^

1914 **

1915 ** See also the [sqlite3_total_changes()] interface, the

1916 ** [count_changes pragma], and the [changes() SQL function].

1917 **

1918 ** If a separate thread makes changes on the same database connection

1919 ** while [sqlite3_changes()] is running then the value returned

1920 ** is unpredictable and not meaningful.

1921 */

1922 int sqlite3_changes(sqlite3*);

1923

1924 /*

1925 ** CAPI3REF: Total Number Of Rows Modified

1926 **

1927 ** ^This function returns the number of row changes caused by [INSERT],

1928 ** [UPDATE] or [DELETE] statements since the [database connection] was opened.

1929 ** ^(The count returned by sqlite3_total_changes() includes all changes

1930 ** from all [CREATE TRIGGER \| trigger] contexts and changes made by

1931 ** [foreign key actions]. However,

1932 ** the count does not include changes used to implement [REPLACE] constraints,

1933 ** do rollbacks or ABORT processing, or [DROP TABLE] processing. The

1934 ** count does not include rows of views that fire an [INSTEAD OF trigger],

1935 ** though if the INSTEAD OF trigger makes changes of its own, those changes

1936 ** are counted.)^

1937 ** ^The sqlite3_total_changes() function counts the changes as soon as

1938 ** the statement that makes them is completed (when the statement handle

1939 ** is passed to [sqlite3_reset()] or [sqlite3_finalize()]).

1940 **

1941 ** See also the [sqlite3_changes()] interface, the

1942 ** [count_changes pragma], and the [total_changes() SQL function].

1943 **

1944 ** If a separate thread makes changes on the same database connection

1945 ** while [sqlite3_total_changes()] is running then the value

1946 ** returned is unpredictable and not meaningful.

1947 */

1948 int sqlite3_total_changes(sqlite3*);

1949

1950 /*

1951 ** CAPI3REF: Interrupt A Long-Running Query

1952 **

1953 ** ^This function causes any pending database operation to abort and

1954 ** return at its earliest opportunity. This routine is typically

1955 ** called in response to a user action such as pressing "Cancel"

1956 ** or Ctrl-C where the user wants a long query operation to halt

1957 ** immediately.

1958 **

1959 ** ^It is safe to call this routine from a thread different from the

1960 ** thread that is currently running the database operation. But it

1961 ** is not safe to call this routine with a [database connection] that

1962 ** is closed or might close before sqlite3_interrupt() returns.

1963 **

1964 ** ^If an SQL operation is very nearly finished at the time when

1965 ** sqlite3_interrupt() is called, then it might not have an opportunity

1966 ** to be interrupted and might continue to completion.

1967 **

1968 ** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].

1969 ** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE

1970 ** that is inside an explicit transaction, then the entire transaction

1971 ** will be rolled back automatically.

1972 **

1973 ** ^The sqlite3_interrupt(D) call is in effect until all currently running

1974 ** SQL statements on [database connection] D complete. ^Any new SQL statements

1975 ** that are started after the sqlite3_interrupt() call and before the

1976 ** running statements reaches zero are interrupted as if they had been

1977 ** running prior to the sqlite3_interrupt() call. ^New SQL statements

1978 ** that are started after the running statement count reaches zero are

1979 ** not effected by the sqlite3_interrupt().

1980 ** ^A call to sqlite3_interrupt(D) that occurs when there are no running

1981 ** SQL statements is a no-op and has no effect on SQL statements

1982 ** that are started after the sqlite3_interrupt() call returns.

1983 **

1984 ** If the database connection closes while [sqlite3_interrupt()]

1985 ** is running then bad things will likely happen.

1986 */

1987 void sqlite3_interrupt(sqlite3*);

1988

1989 /*

1990 ** CAPI3REF: Determine If An SQL Statement Is Complete

1991 **

1992 ** These routines are useful during command-line input to determine if the

1993 ** currently entered text seems to form a complete SQL statement or

1994 ** if additional input is needed before sending the text into

1995 ** SQLite for parsing. ^These routines return 1 if the input string

1996 ** appears to be a complete SQL statement. ^A statement is judged to be

1997 ** complete if it ends with a semicolon token and is not a prefix of a

1998 ** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within

1999 ** string literals or quoted identifier names or comments are not

2000 ** independent tokens (they are part of the token in which they are

2001 ** embedded) and thus do not count as a statement terminator. ^Whitespace

2002 ** and comments that follow the final semicolon are ignored.

2003 **

2004 ** ^These routines return 0 if the statement is incomplete. ^If a

2005 ** memory allocation fails, then SQLITE_NOMEM is returned.

2006 **

2007 ** ^These routines do not parse the SQL statements thus

2008 ** will not detect syntactically incorrect SQL.

2009 **

2010 ** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior

2011 ** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked

2012 ** automatically by sqlite3_complete16(). If that initialization fails,

2013 ** then the return value from sqlite3_complete16() will be non-zero

2014 ** regardless of whether or not the input SQL is complete.)^

2015 **

2016 ** The input to [sqlite3_complete()] must be a zero-terminated

2017 ** UTF-8 string.

2018 **

2019 ** The input to [sqlite3_complete16()] must be a zero-terminated

2020 ** UTF-16 string in native byte order.

2021 */

2022 int sqlite3_complete(const char *sql);

2023 int sqlite3_complete16(const void *sql);

2024

2025 /*

2026 ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors

2027 **

2028 ** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X

2029 ** that might be invoked with argument P whenever

2030 ** an attempt is made to access a database table associated with

2031 ** [database connection] D when another thread

2032 ** or process has the table locked.

2033 ** The sqlite3_busy_handler() interface is used to implement

2034 ** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout].

2035 **

2036 ** ^If the busy callback is NULL, then [SQLITE_BUSY]

2037 ** is returned immediately upon encountering the lock. ^If the busy callback

2038 ** is not NULL, then the callback might be invoked with two arguments.

2039 **

2040 ** ^The first argument to the busy handler is a copy of the void* pointer which

2041 ** is the third argument to sqlite3_busy_handler(). ^The second argument to

2042 ** the busy handler callback is the number of times that the busy handler has

2043 ** been invoked for the same locking event. ^If the

2044 ** busy callback returns 0, then no additional attempts are made to

2045 ** access the database and [SQLITE_BUSY] is returned

2046 ** to the application.

2047 ** ^If the callback returns non-zero, then another attempt

2048 ** is made to access the database and the cycle repeats.

2049 **

2050 ** The presence of a busy handler does not guarantee that it will be invoked

2051 ** when there is lock contention. ^If SQLite determines that invoking the busy

2052 ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]

2053 ** to the application instead of invoking the

2054 ** busy handler.

2055 ** Consider a scenario where one process is holding a read lock that

2056 ** it is trying to promote to a reserved lock and

2057 ** a second process is holding a reserved lock that it is trying

2058 ** to promote to an exclusive lock. The first process cannot proceed

2059 ** because it is blocked by the second and the second process cannot

2060 ** proceed because it is blocked by the first. If both processes

2061 ** invoke the busy handlers, neither will make any progress. Therefore,

2062 ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this

2063 ** will induce the first process to release its read lock and allow

2064 ** the second process to proceed.

2065 **

2066 ** ^The default busy callback is NULL.

2067 **

2068 ** ^(There can only be a single busy handler defined for each

2069 ** [database connection]. Setting a new busy handler clears any

2070 ** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()]

2071 ** or evaluating [PRAGMA busy_timeout=N] will change the

2072 ** busy handler and thus clear any previously set busy handler.

2073 **

2074 ** The busy callback should not take any actions which modify the

2075 ** database connection that invoked the busy handler. In other words,

2076 ** the busy handler is not reentrant. Any such actions

2077 ** result in undefined behavior.

2078 **

2079 ** A busy handler must not close the database connection

2080 ** or [prepared statement] that invoked the busy handler.

2081 */

2082 int sqlite3_busy_handler(sqlite3, int()(void,int), void);

2083

2084 /*

2085 ** CAPI3REF: Set A Busy Timeout

2086 **

2087 ** ^This routine sets a [sqlite3_busy_handler \| busy handler] that sleeps

2088 ** for a specified amount of time when a table is locked. ^The handler

2089 ** will sleep multiple times until at least "ms" milliseconds of sleeping

2090 ** have accumulated. ^After at least "ms" milliseconds of sleeping,

2091 ** the handler returns 0 which causes [sqlite3_step()] to return

2092 ** [SQLITE_BUSY].

2093 **

2094 ** ^Calling this routine with an argument less than or equal to zero

2095 ** turns off all busy handlers.

2096 **

2097 ** ^(There can only be a single busy handler for a particular

2098 ** [database connection] at any given moment. If another busy handler

2099 ** was defined (using [sqlite3_busy_handler()]) prior to calling

2100 ** this routine, that other busy handler is cleared.)^

2101 **

2102 ** See also: [PRAGMA busy_timeout]

2103 */

2104 int sqlite3_busy_timeout(sqlite3*, int ms);

2105

2106 /*

2107 ** CAPI3REF: Convenience Routines For Running Queries

2108 **

2109 ** This is a legacy interface that is preserved for backwards compatibility.

2110 ** Use of this interface is not recommended.

2111 **

2112 ** Definition: A <b>result table</b> is memory data structure created by the

2113 ** [sqlite3_get_table()] interface. A result table records the

2114 ** complete query results from one or more queries.

2115 **

2116 ** The table conceptually has a number of rows and columns. But

2117 ** these numbers are not part of the result table itself. These

2118 ** numbers are obtained separately. Let N be the number of rows

2119 ** and M be the number of columns.

2120 **

2121 ** A result table is an array of pointers to zero-terminated UTF-8 strings.

2122 ** There are (N+1)*M elements in the array. The first M pointers point

2123 ** to zero-terminated strings that contain the names of the columns.

2124 ** The remaining entries all point to query results. NULL values result

2125 ** in NULL pointers. All other values are in their UTF-8 zero-terminated

2126 ** string representation as returned by [sqlite3_column_text()].

2127 **

2128 ** A result table might consist of one or more memory allocations.

2129 ** It is not safe to pass a result table directly to [sqlite3_free()].

2130 ** A result table should be deallocated using [sqlite3_free_table()].

2131 **

2132 ** ^(As an example of the result table format, suppose a query result

2133 ** is as follows:

2134 **

2135 ** <blockquote><pre>

2136 ** Name \| Age

2137 ** -----------------------

2138 ** Alice \| 43

2139 ** Bob \| 28

2140 ** Cindy \| 21

2141 ** </pre></blockquote>

2142 **

2143 ** There are two column (M==2) and three rows (N==3). Thus the

2144 ** result table has 8 entries. Suppose the result table is stored

2145 ** in an array names azResult. Then azResult holds this content:

2146 **

2147 ** <blockquote><pre>

2148 ** azResult[0] = "Name";

2149 ** azResult[1] = "Age";

2150 ** azResult[2] = "Alice";

2151 ** azResult[3] = "43";

2152 ** azResult[4] = "Bob";

2153 ** azResult[5] = "28";

2154 ** azResult[6] = "Cindy";

2155 ** azResult[7] = "21";

2156 ** </pre></blockquote>)^

2157 **

2158 ** ^The sqlite3_get_table() function evaluates one or more

2159 ** semicolon-separated SQL statements in the zero-terminated UTF-8

2160 ** string of its 2nd parameter and returns a result table to the

2161 ** pointer given in its 3rd parameter.

2162 **

2163 ** After the application has finished with the result from sqlite3_get_table(),

2164 ** it must pass the result table pointer to sqlite3_free_table() in order to

2165 ** release the memory that was malloced. Because of the way the

2166 ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling

2167 ** function must not try to call [sqlite3_free()] directly. Only

2168 ** [sqlite3_free_table()] is able to release the memory properly and safely.

2169 **

2170 ** The sqlite3_get_table() interface is implemented as a wrapper around

2171 ** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access

2172 ** to any internal data structures of SQLite. It uses only the public

2173 ** interface defined here. As a consequence, errors that occur in the

2174 ** wrapper layer outside of the internal [sqlite3_exec()] call are not

2175 ** reflected in subsequent calls to [sqlite3_errcode()] or

2176 ** [sqlite3_errmsg()].

2177 */

2178 int sqlite3_get_table(

2179 sqlite3 db, / An open database */

2180 const char zSql, / SQL to be evaluated */

2181 char **pazResult, / Results of the query */

2182 int pnRow, / Number of result rows written here */

2183 int pnColumn, / Number of result columns written here */

2184 char *pzErrmsg / Error msg written here */

2185 );

2186 void sqlite3_free_table(char **result);

2187

2188 /*

2189 ** CAPI3REF: Formatted String Printing Functions

2190 **

2191 ** These routines are work-alikes of the "printf()" family of functions

2192 ** from the standard C library.

2193 **

2194 ** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their

2195 ** results into memory obtained from [sqlite3_malloc()].

2196 ** The strings returned by these two routines should be

2197 ** released by [sqlite3_free()]. ^Both routines return a

2198 ** NULL pointer if [sqlite3_malloc()] is unable to allocate enough

2199 ** memory to hold the resulting string.

2200 **

2201 ** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from

2202 ** the standard C library. The result is written into the

2203 ** buffer supplied as the second parameter whose size is given by

2204 ** the first parameter. Note that the order of the

2205 ** first two parameters is reversed from snprintf().)^ This is an

2206 ** historical accident that cannot be fixed without breaking

2207 ** backwards compatibility. ^(Note also that sqlite3_snprintf()

2208 ** returns a pointer to its buffer instead of the number of

2209 ** characters actually written into the buffer.)^ We admit that

2210 ** the number of characters written would be a more useful return

2211 ** value but we cannot change the implementation of sqlite3_snprintf()

2212 ** now without breaking compatibility.

2213 **

2214 ** ^As long as the buffer size is greater than zero, sqlite3_snprintf()

2215 ** guarantees that the buffer is always zero-terminated. ^The first

2216 ** parameter "n" is the total size of the buffer, including space for

2217 ** the zero terminator. So the longest string that can be completely

2218 ** written will be n-1 characters.

2219 **

2220 ** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().

2221 **

2222 ** These routines all implement some additional formatting

2223 ** options that are useful for constructing SQL statements.

2224 ** All of the usual printf() formatting options apply. In addition, there

2225 ** is are "%q", "%Q", and "%z" options.

2226 **

2227 ** ^(The %q option works like %s in that it substitutes a nul-terminated

2228 ** string from the argument list. But %q also doubles every '\'' character.

2229 ** %q is designed for use inside a string literal.)^ By doubling each '\''

2230 ** character it escapes that character and allows it to be inserted into

2231 ** the string.

2232 **

2233 ** For example, assume the string variable zText contains text as follows:

2234 **

2235 ** <blockquote><pre>

2236 ** char *zText = "It's a happy day!";

2237 ** </pre></blockquote>

2238 **

2239 ** One can use this text in an SQL statement as follows:

2240 **

2241 ** <blockquote><pre>

2242 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText);

2243 ** sqlite3_exec(db, zSQL, 0, 0, 0);

2244 ** sqlite3_free(zSQL);

2245 ** </pre></blockquote>

2246 **

2247 ** Because the %q format string is used, the '\'' character in zText

2248 ** is escaped and the SQL generated is as follows:

2249 **

2250 ** <blockquote><pre>

2251 ** INSERT INTO table1 VALUES('It''s a happy day!')

2252 ** </pre></blockquote>

2253 **

2254 ** This is correct. Had we used %s instead of %q, the generated SQL

2255 ** would have looked like this:

2256 **

2257 ** <blockquote><pre>

2258 ** INSERT INTO table1 VALUES('It's a happy day!');

2259 ** </pre></blockquote>

2260 **

2261 ** This second example is an SQL syntax error. As a general rule you should

2262 ** always use %q instead of %s when inserting text into a string literal.

2263 **

2264 ** ^(The %Q option works like %q except it also adds single quotes around

2265 ** the outside of the total string. Additionally, if the parameter in the

2266 ** argument list is a NULL pointer, %Q substitutes the text "NULL" (without

2267 ** single quotes).)^ So, for example, one could say:

2268 **

2269 ** <blockquote><pre>

2270 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText);

2271 ** sqlite3_exec(db, zSQL, 0, 0, 0);

2272 ** sqlite3_free(zSQL);

2273 ** </pre></blockquote>

2274 **

2275 ** The code above will render a correct SQL statement in the zSQL

2276 ** variable even if the zText variable is a NULL pointer.

2277 **

2278 ** ^(The "%z" formatting option works like "%s" but with the

2279 ** addition that after the string has been read and copied into

2280 ** the result, [sqlite3_free()] is called on the input string.)^

2281 */

2282 char sqlite3_mprintf(const char,...);

2283 char sqlite3_vmprintf(const char, va_list);

2284 char sqlite3_snprintf(int,char,const char*, ...);

2285 char sqlite3_vsnprintf(int,char,const char*, va_list);

2286

2287 /*

2288 ** CAPI3REF: Memory Allocation Subsystem

2289 **

2290 ** The SQLite core uses these three routines for all of its own

2291 ** internal memory allocation needs. "Core" in the previous sentence

2292 ** does not include operating-system specific VFS implementation. The

2293 ** Windows VFS uses native malloc() and free() for some operations.

2294 **

2295 ** ^The sqlite3_malloc() routine returns a pointer to a block

2296 ** of memory at least N bytes in length, where N is the parameter.

2297 ** ^If sqlite3_malloc() is unable to obtain sufficient free

2298 ** memory, it returns a NULL pointer. ^If the parameter N to

2299 ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns

2300 ** a NULL pointer.

2301 **

2302 ** ^The sqlite3_malloc64(N) routine works just like

2303 ** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead

2304 ** of a signed 32-bit integer.

2305 **

2306 ** ^Calling sqlite3_free() with a pointer previously returned

2307 ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so

2308 ** that it might be reused. ^The sqlite3_free() routine is

2309 ** a no-op if is called with a NULL pointer. Passing a NULL pointer

2310 ** to sqlite3_free() is harmless. After being freed, memory

2311 ** should neither be read nor written. Even reading previously freed

2312 ** memory might result in a segmentation fault or other severe error.

2313 ** Memory corruption, a segmentation fault, or other severe error

2314 ** might result if sqlite3_free() is called with a non-NULL pointer that

2315 ** was not obtained from sqlite3_malloc() or sqlite3_realloc().

2316 **

2317 ** ^The sqlite3_realloc(X,N) interface attempts to resize a

2318 ** prior memory allocation X to be at least N bytes.

2319 ** ^If the X parameter to sqlite3_realloc(X,N)

2320 ** is a NULL pointer then its behavior is identical to calling

2321 ** sqlite3_malloc(N).

2322 ** ^If the N parameter to sqlite3_realloc(X,N) is zero or

2323 ** negative then the behavior is exactly the same as calling

2324 ** sqlite3_free(X).

2325 ** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation

2326 ** of at least N bytes in size or NULL if insufficient memory is available.

2327 ** ^If M is the size of the prior allocation, then min(N,M) bytes

2328 ** of the prior allocation are copied into the beginning of buffer returned

2329 ** by sqlite3_realloc(X,N) and the prior allocation is freed.

2330 ** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the

2331 ** prior allocation is not freed.

2332 **

2333 ** ^The sqlite3_realloc64(X,N) interfaces works the same as

2334 ** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead

2335 ** of a 32-bit signed integer.

2336 **

2337 ** ^If X is a memory allocation previously obtained from sqlite3_malloc(),

2338 ** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then

2339 ** sqlite3_msize(X) returns the size of that memory allocation in bytes.

2340 ** ^The value returned by sqlite3_msize(X) might be larger than the number

2341 ** of bytes requested when X was allocated. ^If X is a NULL pointer then

2342 ** sqlite3_msize(X) returns zero. If X points to something that is not

2343 ** the beginning of memory allocation, or if it points to a formerly

2344 ** valid memory allocation that has now been freed, then the behavior

2345 ** of sqlite3_msize(X) is undefined and possibly harmful.

2346 **

2347 ** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(),

2348 ** sqlite3_malloc64(), and sqlite3_realloc64()

2349 ** is always aligned to at least an 8 byte boundary, or to a

2350 ** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time

2351 ** option is used.

2352 **

2353 ** In SQLite version 3.5.0 and 3.5.1, it was possible to define

2354 ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in

2355 ** implementation of these routines to be omitted. That capability

2356 ** is no longer provided. Only built-in memory allocators can be used.

2357 **

2358 ** Prior to SQLite version 3.7.10, the Windows OS interface layer called

2359 ** the system malloc() and free() directly when converting

2360 ** filenames between the UTF-8 encoding used by SQLite

2361 ** and whatever filename encoding is used by the particular Windows

2362 ** installation. Memory allocation errors were detected, but

2363 ** they were reported back as [SQLITE_CANTOPEN] or

2364 ** [SQLITE_IOERR] rather than [SQLITE_NOMEM].

2365 **

2366 ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]

2367 ** must be either NULL or else pointers obtained from a prior

2368 ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have

2369 ** not yet been released.

2370 **

2371 ** The application must not read or write any part of

2372 ** a block of memory after it has been released using

2373 ** [sqlite3_free()] or [sqlite3_realloc()].

2374 */

2375 void *sqlite3_malloc(int);

2376 void *sqlite3_malloc64(sqlite3_uint64);

2377 void sqlite3_realloc(void, int);

2378 void sqlite3_realloc64(void, sqlite3_uint64);

2379 void sqlite3_free(void*);

2380 sqlite3_uint64 sqlite3_msize(void*);

2381

2382 /*

2383 ** CAPI3REF: Memory Allocator Statistics

2384 **

2385 ** SQLite provides these two interfaces for reporting on the status

2386 ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]

2387 ** routines, which form the built-in memory allocation subsystem.

2388 **

2389 ** ^The [sqlite3_memory_used()] routine returns the number of bytes

2390 ** of memory currently outstanding (malloced but not freed).

2391 ** ^The [sqlite3_memory_highwater()] routine returns the maximum

2392 ** value of [sqlite3_memory_used()] since the high-water mark

2393 ** was last reset. ^The values returned by [sqlite3_memory_used()] and

2394 ** [sqlite3_memory_highwater()] include any overhead

2395 ** added by SQLite in its implementation of [sqlite3_malloc()],

2396 ** but not overhead added by the any underlying system library

2397 ** routines that [sqlite3_malloc()] may call.

2398 **

2399 ** ^The memory high-water mark is reset to the current value of

2400 ** [sqlite3_memory_used()] if and only if the parameter to

2401 ** [sqlite3_memory_highwater()] is true. ^The value returned

2402 ** by [sqlite3_memory_highwater(1)] is the high-water mark

2403 ** prior to the reset.

2404 */

2405 sqlite3_int64 sqlite3_memory_used(void);

2406 sqlite3_int64 sqlite3_memory_highwater(int resetFlag);

2407

2408 /*

2409 ** CAPI3REF: Pseudo-Random Number Generator

2410 **

2411 ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to

2412 ** select random [ROWID \| ROWIDs] when inserting new records into a table that

2413 ** already uses the largest possible [ROWID]. The PRNG is also used for

2414 ** the build-in random() and randomblob() SQL functions. This interface allows

2415 ** applications to access the same PRNG for other purposes.

2416 **

2417 ** ^A call to this routine stores N bytes of randomness into buffer P.

2418 ** ^If N is less than one, then P can be a NULL pointer.

2419 **

2420 ** ^If this routine has not been previously called or if the previous

2421 ** call had N less than one, then the PRNG is seeded using randomness

2422 ** obtained from the xRandomness method of the default [sqlite3_vfs] object.

2423 ** ^If the previous call to this routine had an N of 1 or more then

2424 ** the pseudo-randomness is generated

2425 ** internally and without recourse to the [sqlite3_vfs] xRandomness

2426 ** method.

2427 */

2428 void sqlite3_randomness(int N, void *P);

2429

2430 /*

2431 ** CAPI3REF: Compile-Time Authorization Callbacks

2432 **

2433 ** ^This routine registers an authorizer callback with a particular

2434 ** [database connection], supplied in the first argument.

2435 ** ^The authorizer callback is invoked as SQL statements are being compiled

2436 ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],

2437 ** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various

2438 ** points during the compilation process, as logic is being created

2439 ** to perform various actions, the authorizer callback is invoked to

2440 ** see if those actions are allowed. ^The authorizer callback should

2441 ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the

2442 ** specific action but allow the SQL statement to continue to be

2443 ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be

2444 ** rejected with an error. ^If the authorizer callback returns

2445 ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]

2446 ** then the [sqlite3_prepare_v2()] or equivalent call that triggered

2447 ** the authorizer will fail with an error message.

2448 **

2449 ** When the callback returns [SQLITE_OK], that means the operation

2450 ** requested is ok. ^When the callback returns [SQLITE_DENY], the

2451 ** [sqlite3_prepare_v2()] or equivalent call that triggered the

2452 ** authorizer will fail with an error message explaining that

2453 ** access is denied.

2454 **

2455 ** ^The first parameter to the authorizer callback is a copy of the third

2456 ** parameter to the sqlite3_set_authorizer() interface. ^The second parameter

2457 ** to the callback is an integer [SQLITE_COPY \| action code] that specifies

2458 ** the particular action to be authorized. ^The third through sixth parameters

2459 ** to the callback are zero-terminated strings that contain additional

2460 ** details about the action to be authorized.

2461 **

2462 ** ^If the action code is [SQLITE_READ]

2463 ** and the callback returns [SQLITE_IGNORE] then the

2464 ** [prepared statement] statement is constructed to substitute

2465 ** a NULL value in place of the table column that would have

2466 ** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE]

2467 ** return can be used to deny an untrusted user access to individual

2468 ** columns of a table.

2469 ** ^If the action code is [SQLITE_DELETE] and the callback returns

2470 ** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the

2471 ** [truncate optimization] is disabled and all rows are deleted individually.

2472 **

2473 ** An authorizer is used when [sqlite3_prepare \| preparing]

2474 ** SQL statements from an untrusted source, to ensure that the SQL statements

2475 ** do not try to access data they are not allowed to see, or that they do not

2476 ** try to execute malicious statements that damage the database. For

2477 ** example, an application may allow a user to enter arbitrary

2478 ** SQL queries for evaluation by a database. But the application does

2479 ** not want the user to be able to make arbitrary changes to the

2480 ** database. An authorizer could then be put in place while the

2481 ** user-entered SQL is being [sqlite3_prepare \| prepared] that

2482 ** disallows everything except [SELECT] statements.

2483 **

2484 ** Applications that need to process SQL from untrusted sources

2485 ** might also consider lowering resource limits using [sqlite3_limit()]

2486 ** and limiting database size using the [max_page_count] [PRAGMA]

2487 ** in addition to using an authorizer.

2488 **

2489 ** ^(Only a single authorizer can be in place on a database connection

2490 ** at a time. Each call to sqlite3_set_authorizer overrides the

2491 ** previous call.)^ ^Disable the authorizer by installing a NULL callback.

2492 ** The authorizer is disabled by default.

2493 **

2494 ** The authorizer callback must not do anything that will modify

2495 ** the database connection that invoked the authorizer callback.

2496 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their

2497 ** database connections for the meaning of "modify" in this paragraph.

2498 **

2499 ** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the

2500 ** statement might be re-prepared during [sqlite3_step()] due to a

2501 ** schema change. Hence, the application should ensure that the

2502 ** correct authorizer callback remains in place during the [sqlite3_step()].

2503 **

2504 ** ^Note that the authorizer callback is invoked only during

2505 ** [sqlite3_prepare()] or its variants. Authorization is not

2506 ** performed during statement evaluation in [sqlite3_step()], unless

2507 ** as stated in the previous paragraph, sqlite3_step() invokes

2508 ** sqlite3_prepare_v2() to reprepare a statement after a schema change.

2509 */

2510 int sqlite3_set_authorizer(

2511 sqlite3*,

2512 int (xAuth)(void,int,const char,const char,const char,const char),

2513 void *pUserData

2514 );

2515

2516 /*

2517 ** CAPI3REF: Authorizer Return Codes

2518 **

2519 ** The [sqlite3_set_authorizer \| authorizer callback function] must

2520 ** return either [SQLITE_OK] or one of these two constants in order

2521 ** to signal SQLite whether or not the action is permitted. See the

2522 ** [sqlite3_set_authorizer \| authorizer documentation] for additional

2523 ** information.

2524 **

2525 ** Note that SQLITE_IGNORE is also used as a [conflict resolution mode]

2526 ** returned from the [sqlite3_vtab_on_conflict()] interface.

2527 */

2528 #define SQLITE_DENY 1 /* Abort the SQL statement with an error */

2529 #define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */

2530

2531 /*

2532 ** CAPI3REF: Authorizer Action Codes

2533 **

2534 ** The [sqlite3_set_authorizer()] interface registers a callback function

2535 ** that is invoked to authorize certain SQL statement actions. The

2536 ** second parameter to the callback is an integer code that specifies

2537 ** what action is being authorized. These are the integer action codes that

2538 ** the authorizer callback may be passed.

2539 **

2540 ** These action code values signify what kind of operation is to be

2541 ** authorized. The 3rd and 4th parameters to the authorization

2542 ** callback function will be parameters or NULL depending on which of these

2543 ** codes is used as the second parameter. ^(The 5th parameter to the

2544 ** authorizer callback is the name of the database ("main", "temp",

2545 ** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback

2546 ** is the name of the inner-most trigger or view that is responsible for

2547 ** the access attempt or NULL if this access attempt is directly from

2548 ** top-level SQL code.

2549 */

2550 /***************************************** 3rd ******** 4th *********/

2551 #define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */

2552 #define SQLITE_CREATE_TABLE 2 /* Table Name NULL */

2553 #define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */

2554 #define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */

2555 #define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */

2556 #define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */

2557 #define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */

2558 #define SQLITE_CREATE_VIEW 8 /* View Name NULL */

2559 #define SQLITE_DELETE 9 /* Table Name NULL */

2560 #define SQLITE_DROP_INDEX 10 /* Index Name Table Name */

2561 #define SQLITE_DROP_TABLE 11 /* Table Name NULL */

2562 #define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */

2563 #define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */

2564 #define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */

2565 #define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */

2566 #define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */

2567 #define SQLITE_DROP_VIEW 17 /* View Name NULL */

2568 #define SQLITE_INSERT 18 /* Table Name NULL */

2569 #define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */

2570 #define SQLITE_READ 20 /* Table Name Column Name */

2571 #define SQLITE_SELECT 21 /* NULL NULL */

2572 #define SQLITE_TRANSACTION 22 /* Operation NULL */

2573 #define SQLITE_UPDATE 23 /* Table Name Column Name */

2574 #define SQLITE_ATTACH 24 /* Filename NULL */

2575 #define SQLITE_DETACH 25 /* Database Name NULL */

2576 #define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */

2577 #define SQLITE_REINDEX 27 /* Index Name NULL */

2578 #define SQLITE_ANALYZE 28 /* Table Name NULL */

2579 #define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */

2580 #define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */

2581 #define SQLITE_FUNCTION 31 /* NULL Function Name */

2582 #define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */

2583 #define SQLITE_COPY 0 /* No longer used */

2584 #define SQLITE_RECURSIVE 33 /* NULL NULL */

2585

2586 /*

2587 ** CAPI3REF: Tracing And Profiling Functions

2588 **

2589 ** These routines register callback functions that can be used for

2590 ** tracing and profiling the execution of SQL statements.

2591 **

2592 ** ^The callback function registered by sqlite3_trace() is invoked at

2593 ** various times when an SQL statement is being run by [sqlite3_step()].

2594 ** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the

2595 ** SQL statement text as the statement first begins executing.

2596 ** ^(Additional sqlite3_trace() callbacks might occur

2597 ** as each triggered subprogram is entered. The callbacks for triggers

2598 ** contain a UTF-8 SQL comment that identifies the trigger.)^

2599 **

2600 ** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit

2601 ** the length of [bound parameter] expansion in the output of sqlite3_trace().

2602 **

2603 ** ^The callback function registered by sqlite3_profile() is invoked

2604 ** as each SQL statement finishes. ^The profile callback contains

2605 ** the original statement text and an estimate of wall-clock time

2606 ** of how long that statement took to run. ^The profile callback

2607 ** time is in units of nanoseconds, however the current implementation

2608 ** is only capable of millisecond resolution so the six least significant

2609 ** digits in the time are meaningless. Future versions of SQLite

2610 ** might provide greater resolution on the profiler callback. The

2611 ** sqlite3_profile() function is considered experimental and is

2612 ** subject to change in future versions of SQLite.

2613 */

2614 void sqlite3_trace(sqlite3, void(xTrace)(void,const char), void);

2615 SQLITE_EXPERIMENTAL void sqlite3_profile(sqlite3,

2616 void(xProfile)(void,const char,sqlite3_uint64), void);

2617

2618 /*

2619 ** CAPI3REF: Query Progress Callbacks

2620 **

2621 ** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback

2622 ** function X to be invoked periodically during long running calls to

2623 ** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for

2624 ** database connection D. An example use for this

2625 ** interface is to keep a GUI updated during a large query.

2626 **

2627 ** ^The parameter P is passed through as the only parameter to the

2628 ** callback function X. ^The parameter N is the approximate number of

2629 ** [virtual machine instructions] that are evaluated between successive

2630 ** invocations of the callback X. ^If N is less than one then the progress

2631 ** handler is disabled.

2632 **

2633 ** ^Only a single progress handler may be defined at one time per

2634 ** [database connection]; setting a new progress handler cancels the

2635 ** old one. ^Setting parameter X to NULL disables the progress handler.

2636 ** ^The progress handler is also disabled by setting N to a value less

2637 ** than 1.

2638 **

2639 ** ^If the progress callback returns non-zero, the operation is

2640 ** interrupted. This feature can be used to implement a

2641 ** "Cancel" button on a GUI progress dialog box.

2642 **

2643 ** The progress handler callback must not do anything that will modify

2644 ** the database connection that invoked the progress handler.

2645 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their

2646 ** database connections for the meaning of "modify" in this paragraph.

2647 **

2648 */

2649 void sqlite3_progress_handler(sqlite3, int, int()(void), void);

2650

2651 /*

2652 ** CAPI3REF: Opening A New Database Connection

2653 **

2654 ** ^These routines open an SQLite database file as specified by the

2655 ** filename argument. ^The filename argument is interpreted as UTF-8 for

2656 ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte

2657 ** order for sqlite3_open16(). ^(A [database connection] handle is usually

2658 ** returned in *ppDb, even if an error occurs. The only exception is that

2659 ** if SQLite is unable to allocate memory to hold the [sqlite3] object,

2660 ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]

2661 ** object.)^ ^(If the database is opened (and/or created) successfully, then

2662 ** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The

2663 ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain

2664 ** an English language description of the error following a failure of any

2665 ** of the sqlite3_open() routines.

2666 **

2667 ** ^The default encoding will be UTF-8 for databases created using

2668 ** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases

2669 ** created using sqlite3_open16() will be UTF-16 in the native byte order.

2670 **

2671 ** Whether or not an error occurs when it is opened, resources

2672 ** associated with the [database connection] handle should be released by

2673 ** passing it to [sqlite3_close()] when it is no longer required.

2674 **

2675 ** The sqlite3_open_v2() interface works like sqlite3_open()

2676 ** except that it accepts two additional parameters for additional control

2677 ** over the new database connection. ^(The flags parameter to

2678 ** sqlite3_open_v2() can take one of

2679 ** the following three values, optionally combined with the

2680 ** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE],

2681 ** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^

2682 **

2683 ** <dl>

2684 ** ^(<dt>[SQLITE_OPEN_READONLY]</dt>

2685 ** <dd>The database is opened in read-only mode. If the database does not

2686 ** already exist, an error is returned.</dd>)^

2687 **

2688 ** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>

2689 ** <dd>The database is opened for reading and writing if possible, or reading

2690 ** only if the file is write protected by the operating system. In either

2691 ** case the database must already exist, otherwise an error is returned.</dd>)^

2692 **

2693 ** ^(<dt>[SQLITE_OPEN_READWRITE] \| [SQLITE_OPEN_CREATE]</dt>

2694 ** <dd>The database is opened for reading and writing, and is created if

2695 ** it does not already exist. This is the behavior that is always used for

2696 ** sqlite3_open() and sqlite3_open16().</dd>)^

2697 ** </dl>

2698 **

2699 ** If the 3rd parameter to sqlite3_open_v2() is not one of the

2700 ** combinations shown above optionally combined with other

2701 ** [SQLITE_OPEN_READONLY \| SQLITE_OPEN_* bits]

2702 ** then the behavior is undefined.

2703 **

2704 ** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection

2705 ** opens in the multi-thread [threading mode] as long as the single-thread

2706 ** mode has not been set at compile-time or start-time. ^If the

2707 ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens

2708 ** in the serialized [threading mode] unless single-thread was

2709 ** previously selected at compile-time or start-time.

2710 ** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be

2711 ** eligible to use [shared cache mode], regardless of whether or not shared

2712 ** cache is enabled using [sqlite3_enable_shared_cache()]. ^The

2713 ** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not

2714 ** participate in [shared cache mode] even if it is enabled.

2715 **

2716 ** ^The fourth parameter to sqlite3_open_v2() is the name of the

2717 ** [sqlite3_vfs] object that defines the operating system interface that

2718 ** the new database connection should use. ^If the fourth parameter is

2719 ** a NULL pointer then the default [sqlite3_vfs] object is used.

2720 **

2721 ** ^If the filename is ":memory:", then a private, temporary in-memory database

2722 ** is created for the connection. ^This in-memory database will vanish when

2723 ** the database connection is closed. Future versions of SQLite might

2724 ** make use of additional special filenames that begin with the ":" character.

2725 ** It is recommended that when a database filename actually does begin with

2726 ** a ":" character you should prefix the filename with a pathname such as

2727 ** "./" to avoid ambiguity.

2728 **

2729 ** ^If the filename is an empty string, then a private, temporary

2730 ** on-disk database will be created. ^This private database will be

2731 ** automatically deleted as soon as the database connection is closed.

2732 **

2733 ** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>

2734 **

2735 ** ^If [URI filename] interpretation is enabled, and the filename argument

2736 ** begins with "file:", then the filename is interpreted as a URI. ^URI

2737 ** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is

2738 ** set in the fourth argument to sqlite3_open_v2(), or if it has

2739 ** been enabled globally using the [SQLITE_CONFIG_URI] option with the

2740 ** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.

2741 ** As of SQLite version 3.7.7, URI filename interpretation is turned off

2742 ** by default, but future releases of SQLite might enable URI filename

2743 ** interpretation by default. See "[URI filenames]" for additional

2744 ** information.

2745 **

2746 ** URI filenames are parsed according to RFC 3986. ^If the URI contains an

2747 ** authority, then it must be either an empty string or the string

2748 ** "localhost". ^If the authority is not an empty string or "localhost", an

2749 ** error is returned to the caller. ^The fragment component of a URI, if

2750 ** present, is ignored.

2751 **

2752 ** ^SQLite uses the path component of the URI as the name of the disk file

2753 ** which contains the database. ^If the path begins with a '/' character,

2754 ** then it is interpreted as an absolute path. ^If the path does not begin

2755 ** with a '/' (meaning that the authority section is omitted from the URI)

2756 ** then the path is interpreted as a relative path.

2757 ** ^(On windows, the first component of an absolute path

2758 ** is a drive specification (e.g. "C:").)^

2759 **

2760 ** [[core URI query parameters]]

2761 ** The query component of a URI may contain parameters that are interpreted

2762 ** either by SQLite itself, or by a [VFS \| custom VFS implementation].

2763 ** SQLite and its built-in [VFSes] interpret the

2764 ** following query parameters:

2765 **

2766 ** <ul>

2767 ** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of

2768 ** a VFS object that provides the operating system interface that should

2769 ** be used to access the database file on disk. ^If this option is set to

2770 ** an empty string the default VFS object is used. ^Specifying an unknown

2771 ** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is

2772 ** present, then the VFS specified by the option takes precedence over

2773 ** the value passed as the fourth parameter to sqlite3_open_v2().

2774 **

2775 ** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw",

2776 ** "rwc", or "memory". Attempting to set it to any other value is

2777 ** an error)^.

2778 ** ^If "ro" is specified, then the database is opened for read-only

2779 ** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the

2780 ** third argument to sqlite3_open_v2(). ^If the mode option is set to

2781 ** "rw", then the database is opened for read-write (but not create)

2782 ** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had

2783 ** been set. ^Value "rwc" is equivalent to setting both

2784 ** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is

2785 ** set to "memory" then a pure [in-memory database] that never reads

2786 ** or writes from disk is used. ^It is an error to specify a value for

2787 ** the mode parameter that is less restrictive than that specified by

2788 ** the flags passed in the third parameter to sqlite3_open_v2().

2789 **

2790 ** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or

2791 ** "private". ^Setting it to "shared" is equivalent to setting the

2792 ** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to

2793 ** sqlite3_open_v2(). ^Setting the cache parameter to "private" is

2794 ** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.

2795 ** ^If sqlite3_open_v2() is used and the "cache" parameter is present in

2796 ** a URI filename, its value overrides any behavior requested by setting

2797 ** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.

2798 **

2799 ** <li> <b>psow</b>: ^The psow parameter indicates whether or not the

2800 ** [powersafe overwrite] property does or does not apply to the

2801 ** storage media on which the database file resides.

2802 **

2803 ** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter

2804 ** which if set disables file locking in rollback journal modes. This

2805 ** is useful for accessing a database on a filesystem that does not

2806 ** support locking. Caution: Database corruption might result if two

2807 ** or more processes write to the same database and any one of those

2808 ** processes uses nolock=1.

2809 **

2810 ** <li> <b>immutable</b>: ^The immutable parameter is a boolean query

2811 ** parameter that indicates that the database file is stored on

2812 ** read-only media. ^When immutable is set, SQLite assumes that the

2813 ** database file cannot be changed, even by a process with higher

2814 ** privilege, and so the database is opened read-only and all locking

2815 ** and change detection is disabled. Caution: Setting the immutable

2816 ** property on a database file that does in fact change can result

2817 ** in incorrect query results and/or [SQLITE_CORRUPT] errors.

2818 ** See also: [SQLITE_IOCAP_IMMUTABLE].

2819 **

2820 ** </ul>

2821 **

2822 ** ^Specifying an unknown parameter in the query component of a URI is not an

2823 ** error. Future versions of SQLite might understand additional query

2824 ** parameters. See "[query parameters with special meaning to SQLite]" for

2825 ** additional information.

2826 **

2827 ** [[URI filename examples]] <h3>URI filename examples</h3>

2828 **

2829 ** <table border="1" align=center cellpadding=5>

2830 ** <tr><th> URI filenames <th> Results

2831 ** <tr><td> file:data.db <td>

2832 ** Open the file "data.db" in the current directory.

2833 ** <tr><td> file:/home/fred/data.db<br>

2834 ** file:///home/fred/data.db <br>

2835 ** file://localhost/home/fred/data.db <br> <td>

2836 ** Open the database file "/home/fred/data.db".

2837 ** <tr><td> file://darkstar/home/fred/data.db <td>

2838 ** An error. "darkstar" is not a recognized authority.

2839 ** <tr><td style="white-space:nowrap">

2840 ** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db

2841 ** <td> Windows only: Open the file "data.db" on fred's desktop on drive

2842 ** C:. Note that the %20 escaping in this example is not strictly

2843 ** necessary - space characters can be used literally

2844 ** in URI filenames.

2845 ** <tr><td> file:data.db?mode=ro&cache=private <td>

2846 ** Open file "data.db" in the current directory for read-only access.

2847 ** Regardless of whether or not shared-cache mode is enabled by

2848 ** default, use a private cache.

2849 ** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td>

2850 ** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile"

2851 ** that uses dot-files in place of posix advisory locking.

2852 ** <tr><td> file:data.db?mode=readonly <td>

2853 ** An error. "readonly" is not a valid option for the "mode" parameter.

2854 ** </table>

2855 **

2856 ** ^URI hexadecimal escape sequences (%HH) are supported within the path and

2857 ** query components of a URI. A hexadecimal escape sequence consists of a

2858 ** percent sign - "%" - followed by exactly two hexadecimal digits

2859 ** specifying an octet value. ^Before the path or query components of a

2860 ** URI filename are interpreted, they are encoded using UTF-8 and all

2861 ** hexadecimal escape sequences replaced by a single byte containing the

2862 ** corresponding octet. If this process generates an invalid UTF-8 encoding,

2863 ** the results are undefined.

2864 **

2865 ** <b>Note to Windows users:</b> The encoding used for the filename argument

2866 ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever

2867 ** codepage is currently defined. Filenames containing international

2868 ** characters must be converted to UTF-8 prior to passing them into

2869 ** sqlite3_open() or sqlite3_open_v2().

2870 **

2871 ** <b>Note to Windows Runtime users:</b> The temporary directory must be set

2872 ** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various

2873 ** features that require the use of temporary files may fail.

2874 **

2875 ** See also: [sqlite3_temp_directory]

2876 */

2877 int sqlite3_open(

2878 const char filename, / Database filename (UTF-8) */

2879 sqlite3 *ppDb / OUT: SQLite db handle */

2880 );

2881 int sqlite3_open16(

2882 const void filename, / Database filename (UTF-16) */

2883 sqlite3 *ppDb / OUT: SQLite db handle */

2884 );

2885 int sqlite3_open_v2(

2886 const char filename, / Database filename (UTF-8) */

2887 sqlite3 *ppDb, / OUT: SQLite db handle */

2888 int flags, /* Flags */

2889 const char zVfs / Name of VFS module to use */

2890 );

2891

2892 /*

2893 ** CAPI3REF: Obtain Values For URI Parameters

2894 **

2895 ** These are utility routines, useful to VFS implementations, that check

2896 ** to see if a database file was a URI that contained a specific query

2897 ** parameter, and if so obtains the value of that query parameter.

2898 **

2899 ** If F is the database filename pointer passed into the xOpen() method of

2900 ** a VFS implementation when the flags parameter to xOpen() has one or

2901 ** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and

2902 ** P is the name of the query parameter, then

2903 ** sqlite3_uri_parameter(F,P) returns the value of the P

2904 ** parameter if it exists or a NULL pointer if P does not appear as a

2905 ** query parameter on F. If P is a query parameter of F

2906 ** has no explicit value, then sqlite3_uri_parameter(F,P) returns

2907 ** a pointer to an empty string.

2908 **

2909 ** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean

2910 ** parameter and returns true (1) or false (0) according to the value

2911 ** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the

2912 ** value of query parameter P is one of "yes", "true", or "on" in any

2913 ** case or if the value begins with a non-zero number. The

2914 ** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of

2915 ** query parameter P is one of "no", "false", or "off" in any case or

2916 ** if the value begins with a numeric zero. If P is not a query

2917 ** parameter on F or if the value of P is does not match any of the

2918 ** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).

2919 **

2920 ** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a

2921 ** 64-bit signed integer and returns that integer, or D if P does not

2922 ** exist. If the value of P is something other than an integer, then

2923 ** zero is returned.

2924 **

2925 ** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and

2926 ** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and

2927 ** is not a database file pathname pointer that SQLite passed into the xOpen

2928 ** VFS method, then the behavior of this routine is undefined and probably

2929 ** undesirable.

2930 */

2931 const char sqlite3_uri_parameter(const char zFilename, const char *zParam);

2932 int sqlite3_uri_boolean(const char zFile, const char zParam, int bDefault);

2933 sqlite3_int64 sqlite3_uri_int64(const char, const char, sqlite3_int64);

2934

2935

2936 /*

2937 ** CAPI3REF: Error Codes And Messages

2938 **

2939 ** ^The sqlite3_errcode() interface returns the numeric [result code] or

2940 ** [extended result code] for the most recent failed sqlite3_* API call

2941 ** associated with a [database connection]. If a prior API call failed

2942 ** but the most recent API call succeeded, the return value from

2943 ** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode()

2944 ** interface is the same except that it always returns the

2945 ** [extended result code] even when extended result codes are

2946 ** disabled.

2947 **

2948 ** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language

2949 ** text that describes the error, as either UTF-8 or UTF-16 respectively.

2950 ** ^(Memory to hold the error message string is managed internally.

2951 ** The application does not need to worry about freeing the result.

2952 ** However, the error string might be overwritten or deallocated by

2953 ** subsequent calls to other SQLite interface functions.)^

2954 **

2955 ** ^The sqlite3_errstr() interface returns the English-language text

2956 ** that describes the [result code], as UTF-8.

2957 ** ^(Memory to hold the error message string is managed internally

2958 ** and must not be freed by the application)^.

2959 **

2960 ** When the serialized [threading mode] is in use, it might be the

2961 ** case that a second error occurs on a separate thread in between

2962 ** the time of the first error and the call to these interfaces.

2963 ** When that happens, the second error will be reported since these

2964 ** interfaces always report the most recent result. To avoid

2965 ** this, each thread can obtain exclusive use of the [database connection] D

2966 ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning

2967 ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after

2968 ** all calls to the interfaces listed here are completed.

2969 **

2970 ** If an interface fails with SQLITE_MISUSE, that means the interface

2971 ** was invoked incorrectly by the application. In that case, the

2972 ** error code and message may or may not be set.

2973 */

2974 int sqlite3_errcode(sqlite3 *db);

2975 int sqlite3_extended_errcode(sqlite3 *db);

2976 const char sqlite3_errmsg(sqlite3);

2977 const void sqlite3_errmsg16(sqlite3);

2978 const char *sqlite3_errstr(int);

2979

2980 /*

2981 ** CAPI3REF: SQL Statement Object

2982 ** KEYWORDS: {prepared statement} {prepared statements}

2983 **

2984 ** An instance of this object represents a single SQL statement.

2985 ** This object is variously known as a "prepared statement" or a

2986 ** "compiled SQL statement" or simply as a "statement".

2987 **

2988 ** The life of a statement object goes something like this:

2989 **

2990 ** <ol>

2991 ** <li> Create the object using [sqlite3_prepare_v2()] or a related

2992 ** function.

2993 ** <li> Bind values to [host parameters] using the sqlite3_bind_*()

2994 ** interfaces.

2995 ** <li> Run the SQL by calling [sqlite3_step()] one or more times.

2996 ** <li> Reset the statement using [sqlite3_reset()] then go back

2997 ** to step 2. Do this zero or more times.

2998 ** <li> Destroy the object using [sqlite3_finalize()].

2999 ** </ol>

3000 **

3001 ** Refer to documentation on individual methods above for additional

3002 ** information.

3003 */

3004 typedef struct sqlite3_stmt sqlite3_stmt;

3005

3006 /*

3007 ** CAPI3REF: Run-time Limits

3008 **

3009 ** ^(This interface allows the size of various constructs to be limited

3010 ** on a connection by connection basis. The first parameter is the

3011 ** [database connection] whose limit is to be set or queried. The

3012 ** second parameter is one of the [limit categories] that define a

3013 ** class of constructs to be size limited. The third parameter is the

3014 ** new limit for that construct.)^

3015 **

3016 ** ^If the new limit is a negative number, the limit is unchanged.

3017 ** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a

3018 ** [limits \| hard upper bound]

3019 ** set at compile-time by a C preprocessor macro called

3020 ** [limits \| SQLITE_MAX_<i>NAME</i>].

3021 ** (The "_LIMIT_" in the name is changed to "_MAX_".))^

3022 ** ^Attempts to increase a limit above its hard upper bound are

3023 ** silently truncated to the hard upper bound.

3024 **

3025 ** ^Regardless of whether or not the limit was changed, the

3026 ** [sqlite3_limit()] interface returns the prior value of the limit.

3027 ** ^Hence, to find the current value of a limit without changing it,

3028 ** simply invoke this interface with the third parameter set to -1.

3029 **

3030 ** Run-time limits are intended for use in applications that manage

3031 ** both their own internal database and also databases that are controlled

3032 ** by untrusted external sources. An example application might be a

3033 ** web browser that has its own databases for storing history and

3034 ** separate databases controlled by JavaScript applications downloaded

3035 ** off the Internet. The internal databases can be given the

3036 ** large, default limits. Databases managed by external sources can

3037 ** be given much smaller limits designed to prevent a denial of service

3038 ** attack. Developers might also want to use the [sqlite3_set_authorizer()]

3039 ** interface to further control untrusted SQL. The size of the database

3040 ** created by an untrusted script can be contained using the

3041 ** [max_page_count] [PRAGMA].

3042 **

3043 ** New run-time limit categories may be added in future releases.

3044 */

3045 int sqlite3_limit(sqlite3*, int id, int newVal);

3046

3047 /*

3048 ** CAPI3REF: Run-Time Limit Categories

3049 ** KEYWORDS: {limit category} {*limit categories}

3050 **

3051 ** These constants define various performance limits

3052 ** that can be lowered at run-time using [sqlite3_limit()].

3053 ** The synopsis of the meanings of the various limits is shown below.

3054 ** Additional information is available at [limits \| Limits in SQLite].

3055 **

3056 ** <dl>

3057 ** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt>

3058 ** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^

3059 **

3060 ** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>

3061 ** <dd>The maximum length of an SQL statement, in bytes.</dd>)^

3062 **

3063 ** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt>

3064 ** <dd>The maximum number of columns in a table definition or in the

3065 ** result set of a [SELECT] or the maximum number of columns in an index

3066 ** or in an ORDER BY or GROUP BY clause.</dd>)^

3067 **

3068 ** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>

3069 ** <dd>The maximum depth of the parse tree on any expression.</dd>)^

3070 **

3071 ** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>

3072 ** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^

3073 **

3074 ** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>

3075 ** <dd>The maximum number of instructions in a virtual machine program

3076 ** used to implement an SQL statement. This limit is not currently

3077 ** enforced, though that might be added in some future release of

3078 ** SQLite.</dd>)^

3079 **

3080 ** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>

3081 ** <dd>The maximum number of arguments on a function.</dd>)^

3082 **

3083 ** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt>

3084 ** <dd>The maximum number of [ATTACH \| attached databases].)^</dd>

3085 **

3086 ** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]]

3087 ** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>

3088 ** <dd>The maximum length of the pattern argument to the [LIKE] or

3089 ** [GLOB] operators.</dd>)^

3090 **

3091 ** [[SQLITE_LIMIT_VARIABLE_NUMBER]]

3092 ** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>

3093 ** <dd>The maximum index number of any [parameter] in an SQL statement.)^

3094 **

3095 ** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>

3096 ** <dd>The maximum depth of recursion for triggers.</dd>)^

3097 **

3098 ** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt>

3099 ** <dd>The maximum number of auxiliary worker threads that a single

3100 ** [prepared statement] may start.</dd>)^

3101 ** </dl>

3102 */

3103 #define SQLITE_LIMIT_LENGTH 0

3104 #define SQLITE_LIMIT_SQL_LENGTH 1

3105 #define SQLITE_LIMIT_COLUMN 2

3106 #define SQLITE_LIMIT_EXPR_DEPTH 3

3107 #define SQLITE_LIMIT_COMPOUND_SELECT 4

3108 #define SQLITE_LIMIT_VDBE_OP 5

3109 #define SQLITE_LIMIT_FUNCTION_ARG 6

3110 #define SQLITE_LIMIT_ATTACHED 7

3111 #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8

3112 #define SQLITE_LIMIT_VARIABLE_NUMBER 9

3113 #define SQLITE_LIMIT_TRIGGER_DEPTH 10

3114 #define SQLITE_LIMIT_WORKER_THREADS 11

3115

3116 /*

3117 ** CAPI3REF: Compiling An SQL Statement

3118 ** KEYWORDS: {SQL statement compiler}

3119 **

3120 ** To execute an SQL query, it must first be compiled into a byte-code

3121 ** program using one of these routines.

3122 **

3123 ** The first argument, "db", is a [database connection] obtained from a

3124 ** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or

3125 ** [sqlite3_open16()]. The database connection must not have been closed.

3126 **

3127 ** The second argument, "zSql", is the statement to be compiled, encoded

3128 ** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2()

3129 ** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2()

3130 ** use UTF-16.

3131 **

3132 ** ^If the nByte argument is less than zero, then zSql is read up to the

3133 ** first zero terminator. ^If nByte is non-negative, then it is the maximum

3134 ** number of bytes read from zSql. ^When nByte is non-negative, the

3135 ** zSql string ends at either the first '\000' or '\u0000' character or

3136 ** the nByte-th byte, whichever comes first. If the caller knows

3137 ** that the supplied string is nul-terminated, then there is a small

3138 ** performance advantage to be gained by passing an nByte parameter that

3139 ** is equal to the number of bytes in the input string <i>including</i>

3140 ** the nul-terminator bytes as this saves SQLite from having to

3141 ** make a copy of the input string.

3142 **

3143 ** ^If pzTail is not NULL then *pzTail is made to point to the first byte

3144 ** past the end of the first SQL statement in zSql. These routines only

3145 ** compile the first statement in zSql, so *pzTail is left pointing to

3146 ** what remains uncompiled.

3147 **

3148 ** ^*ppStmt is left pointing to a compiled [prepared statement] that can be

3149 ** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set

3150 ** to NULL. ^If the input text contains no SQL (if the input is an empty

3151 ** string or a comment) then *ppStmt is set to NULL.

3152 ** The calling procedure is responsible for deleting the compiled

3153 ** SQL statement using [sqlite3_finalize()] after it has finished with it.

3154 ** ppStmt may not be NULL.

3155 **

3156 ** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];

3157 ** otherwise an [error code] is returned.

3158 **

3159 ** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are

3160 ** recommended for all new programs. The two older interfaces are retained

3161 ** for backwards compatibility, but their use is discouraged.

3162 ** ^In the "v2" interfaces, the prepared statement

3163 ** that is returned (the [sqlite3_stmt] object) contains a copy of the

3164 ** original SQL text. This causes the [sqlite3_step()] interface to

3165 ** behave differently in three ways:

3166 **

3167 ** <ol>

3168 ** <li>

3169 ** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it

3170 ** always used to do, [sqlite3_step()] will automatically recompile the SQL

3171 ** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY]

3172 ** retries will occur before sqlite3_step() gives up and returns an error.

3173 ** </li>

3174 **

3175 ** <li>

3176 ** ^When an error occurs, [sqlite3_step()] will return one of the detailed

3177 ** [error codes] or [extended error codes]. ^The legacy behavior was that

3178 ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code

3179 ** and the application would have to make a second call to [sqlite3_reset()]

3180 ** in order to find the underlying cause of the problem. With the "v2" prepare

3181 ** interfaces, the underlying reason for the error is returned immediately.

3182 ** </li>

3183 **

3184 ** <li>

3185 ** ^If the specific value bound to [parameter \| host parameter] in the

3186 ** WHERE clause might influence the choice of query plan for a statement,

3187 ** then the statement will be automatically recompiled, as if there had been

3188 ** a schema change, on the first [sqlite3_step()] call following any change

3189 ** to the [sqlite3_bind_text \| bindings] of that [parameter].

3190 ** ^The specific value of WHERE-clause [parameter] might influence the

3191 ** choice of query plan if the parameter is the left-hand side of a [LIKE]

3192 ** or [GLOB] operator or if the parameter is compared to an indexed column

3193 ** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled.

3194 ** </li>

3195 ** </ol>

3196 */

3197 int sqlite3_prepare(

3198 sqlite3 db, / Database handle */

3199 const char zSql, / SQL statement, UTF-8 encoded */

3200 int nByte, /* Maximum length of zSql in bytes. */

3201 sqlite3_stmt *ppStmt, / OUT: Statement handle */

3202 const char *pzTail / OUT: Pointer to unused portion of zSql */

3203 );

3204 int sqlite3_prepare_v2(

3205 sqlite3 db, / Database handle */

3206 const char zSql, / SQL statement, UTF-8 encoded */

3207 int nByte, /* Maximum length of zSql in bytes. */

3208 sqlite3_stmt *ppStmt, / OUT: Statement handle */

3209 const char *pzTail / OUT: Pointer to unused portion of zSql */

3210 );

3211 int sqlite3_prepare16(

3212 sqlite3 db, / Database handle */

3213 const void zSql, / SQL statement, UTF-16 encoded */

3214 int nByte, /* Maximum length of zSql in bytes. */

3215 sqlite3_stmt *ppStmt, / OUT: Statement handle */

3216 const void *pzTail / OUT: Pointer to unused portion of zSql */

3217 );

3218 int sqlite3_prepare16_v2(

3219 sqlite3 db, / Database handle */

3220 const void zSql, / SQL statement, UTF-16 encoded */

3221 int nByte, /* Maximum length of zSql in bytes. */

3222 sqlite3_stmt *ppStmt, / OUT: Statement handle */

3223 const void *pzTail / OUT: Pointer to unused portion of zSql */

3224 );

3225

3226 /*

3227 ** CAPI3REF: Retrieving Statement SQL

3228 **

3229 ** ^This interface can be used to retrieve a saved copy of the original

3230 ** SQL text used to create a [prepared statement] if that statement was

3231 ** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()].

3232 */

3233 const char sqlite3_sql(sqlite3_stmt pStmt);

3234

3235 /*

3236 ** CAPI3REF: Determine If An SQL Statement Writes The Database

3237 **

3238 ** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if

3239 ** and only if the [prepared statement] X makes no direct changes to

3240 ** the content of the database file.

3241 **

3242 ** Note that [application-defined SQL functions] or

3243 ** [virtual tables] might change the database indirectly as a side effect.

3244 ** ^(For example, if an application defines a function "eval()" that

3245 ** calls [sqlite3_exec()], then the following SQL statement would

3246 ** change the database file through side-effects:

3247 **

3248 ** <blockquote><pre>

3249 ** SELECT eval('DELETE FROM t1') FROM t2;

3250 ** </pre></blockquote>

3251 **

3252 ** But because the [SELECT] statement does not change the database file

3253 ** directly, sqlite3_stmt_readonly() would still return true.)^

3254 **

3255 ** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],

3256 ** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,

3257 ** since the statements themselves do not actually modify the database but

3258 ** rather they control the timing of when other statements modify the

3259 ** database. ^The [ATTACH] and [DETACH] statements also cause

3260 ** sqlite3_stmt_readonly() to return true since, while those statements

3261 ** change the configuration of a database connection, they do not make

3262 ** changes to the content of the database files on disk.

3263 */

3264 int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);

3265

3266 /*

3267 ** CAPI3REF: Determine If A Prepared Statement Has Been Reset

3268 **

3269 ** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the

3270 ** [prepared statement] S has been stepped at least once using

3271 ** [sqlite3_step(S)] but has not run to completion and/or has not

3272 ** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S)

3273 ** interface returns false if S is a NULL pointer. If S is not a

3274 ** NULL pointer and is not a pointer to a valid [prepared statement]

3275 ** object, then the behavior is undefined and probably undesirable.

3276 **

3277 ** This interface can be used in combination [sqlite3_next_stmt()]

3278 ** to locate all prepared statements associated with a database

3279 ** connection that are in need of being reset. This can be used,

3280 ** for example, in diagnostic routines to search for prepared

3281 ** statements that are holding a transaction open.

3282 */

3283 int sqlite3_stmt_busy(sqlite3_stmt*);

3284

3285 /*

3286 ** CAPI3REF: Dynamically Typed Value Object

3287 ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}

3288 **

3289 ** SQLite uses the sqlite3_value object to represent all values

3290 ** that can be stored in a database table. SQLite uses dynamic typing

3291 ** for the values it stores. ^Values stored in sqlite3_value objects

3292 ** can be integers, floating point values, strings, BLOBs, or NULL.

3293 **

3294 ** An sqlite3_value object may be either "protected" or "unprotected".

3295 ** Some interfaces require a protected sqlite3_value. Other interfaces

3296 ** will accept either a protected or an unprotected sqlite3_value.

3297 ** Every interface that accepts sqlite3_value arguments specifies

3298 ** whether or not it requires a protected sqlite3_value.

3299 **

3300 ** The terms "protected" and "unprotected" refer to whether or not

3301 ** a mutex is held. An internal mutex is held for a protected

3302 ** sqlite3_value object but no mutex is held for an unprotected

3303 ** sqlite3_value object. If SQLite is compiled to be single-threaded

3304 ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)

3305 ** or if SQLite is run in one of reduced mutex modes

3306 ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]

3307 ** then there is no distinction between protected and unprotected

3308 ** sqlite3_value objects and they can be used interchangeably. However,

3309 ** for maximum code portability it is recommended that applications

3310 ** still make the distinction between protected and unprotected

3311 ** sqlite3_value objects even when not strictly required.

3312 **

3313 ** ^The sqlite3_value objects that are passed as parameters into the

3314 ** implementation of [application-defined SQL functions] are protected.

3315 ** ^The sqlite3_value object returned by

3316 ** [sqlite3_column_value()] is unprotected.

3317 ** Unprotected sqlite3_value objects may only be used with

3318 ** [sqlite3_result_value()] and [sqlite3_bind_value()].

3319 ** The [sqlite3_value_blob \| sqlite3_value_type()] family of

3320 ** interfaces require protected sqlite3_value objects.

3321 */

3322 typedef struct Mem sqlite3_value;

3323

3324 /*

3325 ** CAPI3REF: SQL Function Context Object

3326 **

3327 ** The context in which an SQL function executes is stored in an

3328 ** sqlite3_context object. ^A pointer to an sqlite3_context object

3329 ** is always first parameter to [application-defined SQL functions].

3330 ** The application-defined SQL function implementation will pass this

3331 ** pointer through into calls to [sqlite3_result_int \| sqlite3_result()],

3332 ** [sqlite3_aggregate_context()], [sqlite3_user_data()],

3333 ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],

3334 ** and/or [sqlite3_set_auxdata()].

3335 */

3336 typedef struct sqlite3_context sqlite3_context;

3337

3338 /*

3339 ** CAPI3REF: Binding Values To Prepared Statements

3340 ** KEYWORDS: {host parameter} {host parameters} {host parameter name}

3341 ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}

3342 **

3343 ** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,

3344 ** literals may be replaced by a [parameter] that matches one of following

3345 ** templates:

3346 **

3347 ** <ul>

3348 ** <li> ?

3349 ** <li> ?NNN

3350 ** <li> :VVV

3351 ** <li> @VVV

3352 ** <li> $VVV

3353 ** </ul>

3354 **

3355 ** In the templates above, NNN represents an integer literal,

3356 ** and VVV represents an alphanumeric identifier.)^ ^The values of these

3357 ** parameters (also called "host parameter names" or "SQL parameters")

3358 ** can be set using the sqlite3_bind_*() routines defined here.

3359 **

3360 ** ^The first argument to the sqlite3_bind_*() routines is always

3361 ** a pointer to the [sqlite3_stmt] object returned from

3362 ** [sqlite3_prepare_v2()] or its variants.

3363 **

3364 ** ^The second argument is the index of the SQL parameter to be set.

3365 ** ^The leftmost SQL parameter has an index of 1. ^When the same named

3366 ** SQL parameter is used more than once, second and subsequent

3367 ** occurrences have the same index as the first occurrence.

3368 ** ^The index for named parameters can be looked up using the

3369 ** [sqlite3_bind_parameter_index()] API if desired. ^The index

3370 ** for "?NNN" parameters is the value of NNN.

3371 ** ^The NNN value must be between 1 and the [sqlite3_limit()]

3372 ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999).

3373 **

3374 ** ^The third argument is the value to bind to the parameter.

3375 ** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16()

3376 ** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter

3377 ** is ignored and the end result is the same as sqlite3_bind_null().

3378 **

3379 ** ^(In those routines that have a fourth argument, its value is the

3380 ** number of bytes in the parameter. To be clear: the value is the

3381 ** number of <u>bytes</u> in the value, not the number of characters.)^

3382 ** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()

3383 ** is negative, then the length of the string is

3384 ** the number of bytes up to the first zero terminator.

3385 ** If the fourth parameter to sqlite3_bind_blob() is negative, then

3386 ** the behavior is undefined.

3387 ** If a non-negative fourth parameter is provided to sqlite3_bind_text()

3388 ** or sqlite3_bind_text16() or sqlite3_bind_text64() then

3389 ** that parameter must be the byte offset

3390 ** where the NUL terminator would occur assuming the string were NUL

3391 ** terminated. If any NUL characters occur at byte offsets less than

3392 ** the value of the fourth parameter then the resulting string value will

3393 ** contain embedded NULs. The result of expressions involving strings

3394 ** with embedded NULs is undefined.

3395 **

3396 ** ^The fifth argument to the BLOB and string binding interfaces

3397 ** is a destructor used to dispose of the BLOB or

3398 ** string after SQLite has finished with it. ^The destructor is called

3399 ** to dispose of the BLOB or string even if the call to bind API fails.

3400 ** ^If the fifth argument is

3401 ** the special value [SQLITE_STATIC], then SQLite assumes that the

3402 ** information is in static, unmanaged space and does not need to be freed.

3403 ** ^If the fifth argument has the value [SQLITE_TRANSIENT], then

3404 ** SQLite makes its own private copy of the data immediately, before

3405 ** the sqlite3_bind_*() routine returns.

3406 **

3407 ** ^The sixth argument to sqlite3_bind_text64() must be one of

3408 ** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]

3409 ** to specify the encoding of the text in the third parameter. If

3410 ** the sixth argument to sqlite3_bind_text64() is not one of the

3411 ** allowed values shown above, or if the text encoding is different

3412 ** from the encoding specified by the sixth parameter, then the behavior

3413 ** is undefined.

3414 **

3415 ** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that

3416 ** is filled with zeroes. ^A zeroblob uses a fixed amount of memory

3417 ** (just an integer to hold its size) while it is being processed.

3418 ** Zeroblobs are intended to serve as placeholders for BLOBs whose

3419 ** content is later written using

3420 ** [sqlite3_blob_open \| incremental BLOB I/O] routines.

3421 ** ^A negative value for the zeroblob results in a zero-length BLOB.

3422 **

3423 ** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer

3424 ** for the [prepared statement] or with a prepared statement for which

3425 ** [sqlite3_step()] has been called more recently than [sqlite3_reset()],

3426 ** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_()

3427 ** routine is passed a [prepared statement] that has been finalized, the

3428 ** result is undefined and probably harmful.

3429 **

3430 ** ^Bindings are not cleared by the [sqlite3_reset()] routine.

3431 ** ^Unbound parameters are interpreted as NULL.

3432 **

3433 ** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an

3434 ** [error code] if anything goes wrong.

3435 ** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB

3436 ** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or

3437 ** [SQLITE_MAX_LENGTH].

3438 ** ^[SQLITE_RANGE] is returned if the parameter

3439 ** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails.

3440 **

3441 ** See also: [sqlite3_bind_parameter_count()],

3442 ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].

3443 */

3444 int sqlite3_bind_blob(sqlite3_stmt, int, const void, int n, void()(void));

3445 int sqlite3_bind_blob64(sqlite3_stmt, int, const void, sqlite3_uint64,

3446 void()(void));

3447 int sqlite3_bind_double(sqlite3_stmt*, int, double);

3448 int sqlite3_bind_int(sqlite3_stmt*, int, int);

3449 int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);

3450 int sqlite3_bind_null(sqlite3_stmt*, int);

3451 int sqlite3_bind_text(sqlite3_stmt,int,const char,int,void()(void));

3452 int sqlite3_bind_text16(sqlite3_stmt, int, const void, int, void()(void));

3453 int sqlite3_bind_text64(sqlite3_stmt, int, const char, sqlite3_uint64,

3454 void()(void), unsigned char encoding);

3455 int sqlite3_bind_value(sqlite3_stmt, int, const sqlite3_value);

3456 int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);

3457

3458 /*

3459 ** CAPI3REF: Number Of SQL Parameters

3460 **

3461 ** ^This routine can be used to find the number of [SQL parameters]

3462 ** in a [prepared statement]. SQL parameters are tokens of the

3463 ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as

3464 ** placeholders for values that are [sqlite3_bind_blob \| bound]

3465 ** to the parameters at a later time.

3466 **

3467 ** ^(This routine actually returns the index of the largest (rightmost)

3468 ** parameter. For all forms except ?NNN, this will correspond to the

3469 ** number of unique parameters. If parameters of the ?NNN form are used,

3470 ** there may be gaps in the list.)^

3471 **

3472 ** See also: [sqlite3_bind_blob\|sqlite3_bind()],

3473 ** [sqlite3_bind_parameter_name()], and

3474 ** [sqlite3_bind_parameter_index()].

3475 */

3476 int sqlite3_bind_parameter_count(sqlite3_stmt*);

3477

3478 /*

3479 ** CAPI3REF: Name Of A Host Parameter

3480 **

3481 ** ^The sqlite3_bind_parameter_name(P,N) interface returns

3482 ** the name of the N-th [SQL parameter] in the [prepared statement] P.

3483 ** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"

3484 ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"

3485 ** respectively.

3486 ** In other words, the initial ":" or "$" or "@" or "?"

3487 ** is included as part of the name.)^

3488 ** ^Parameters of the form "?" without a following integer have no name

3489 ** and are referred to as "nameless" or "anonymous parameters".

3490 **

3491 ** ^The first host parameter has an index of 1, not 0.

3492 **

3493 ** ^If the value N is out of range or if the N-th parameter is

3494 ** nameless, then NULL is returned. ^The returned string is

3495 ** always in UTF-8 encoding even if the named parameter was

3496 ** originally specified as UTF-16 in [sqlite3_prepare16()] or

3497 ** [sqlite3_prepare16_v2()].

3498 **

3499 ** See also: [sqlite3_bind_blob\|sqlite3_bind()],

3500 ** [sqlite3_bind_parameter_count()], and

3501 ** [sqlite3_bind_parameter_index()].

3502 */

3503 const char sqlite3_bind_parameter_name(sqlite3_stmt, int);

3504

3505 /*

3506 ** CAPI3REF: Index Of A Parameter With A Given Name

3507 **

3508 ** ^Return the index of an SQL parameter given its name. ^The

3509 ** index value returned is suitable for use as the second

3510 ** parameter to [sqlite3_bind_blob\|sqlite3_bind()]. ^A zero

3511 ** is returned if no matching parameter is found. ^The parameter

3512 ** name must be given in UTF-8 even if the original statement

3513 ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()].

3514 **

3515 ** See also: [sqlite3_bind_blob\|sqlite3_bind()],

3516 ** [sqlite3_bind_parameter_count()], and

3517 ** [sqlite3_bind_parameter_index()].

3518 */

3519 int sqlite3_bind_parameter_index(sqlite3_stmt, const char zName);

3520

3521 /*

3522 ** CAPI3REF: Reset All Bindings On A Prepared Statement

3523 **

3524 ** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset

3525 ** the [sqlite3_bind_blob \| bindings] on a [prepared statement].

3526 ** ^Use this routine to reset all host parameters to NULL.

3527 */

3528 int sqlite3_clear_bindings(sqlite3_stmt*);

3529

3530 /*

3531 ** CAPI3REF: Number Of Columns In A Result Set

3532 **

3533 ** ^Return the number of columns in the result set returned by the

3534 ** [prepared statement]. ^This routine returns 0 if pStmt is an SQL

3535 ** statement that does not return data (for example an [UPDATE]).

3536 **

3537 ** See also: [sqlite3_data_count()]

3538 */

3539 int sqlite3_column_count(sqlite3_stmt *pStmt);

3540

3541 /*

3542 ** CAPI3REF: Column Names In A Result Set

3543 **

3544 ** ^These routines return the name assigned to a particular column

3545 ** in the result set of a [SELECT] statement. ^The sqlite3_column_name()

3546 ** interface returns a pointer to a zero-terminated UTF-8 string

3547 ** and sqlite3_column_name16() returns a pointer to a zero-terminated

3548 ** UTF-16 string. ^The first parameter is the [prepared statement]

3549 ** that implements the [SELECT] statement. ^The second parameter is the

3550 ** column number. ^The leftmost column is number 0.

3551 **

3552 ** ^The returned string pointer is valid until either the [prepared statement]

3553 ** is destroyed by [sqlite3_finalize()] or until the statement is automatically

3554 ** reprepared by the first call to [sqlite3_step()] for a particular run

3555 ** or until the next call to

3556 ** sqlite3_column_name() or sqlite3_column_name16() on the same column.

3557 **

3558 ** ^If sqlite3_malloc() fails during the processing of either routine

3559 ** (for example during a conversion from UTF-8 to UTF-16) then a

3560 ** NULL pointer is returned.

3561 **

3562 ** ^The name of a result column is the value of the "AS" clause for

3563 ** that column, if there is an AS clause. If there is no AS clause

3564 ** then the name of the column is unspecified and may change from

3565 ** one release of SQLite to the next.

3566 */

3567 const char sqlite3_column_name(sqlite3_stmt, int N);

3568 const void sqlite3_column_name16(sqlite3_stmt, int N);

3569

3570 /*

3571 ** CAPI3REF: Source Of Data In A Query Result

3572 **

3573 ** ^These routines provide a means to determine the database, table, and

3574 ** table column that is the origin of a particular result column in

3575 ** [SELECT] statement.

3576 ** ^The name of the database or table or column can be returned as

3577 ** either a UTF-8 or UTF-16 string. ^The _database_ routines return

3578 ** the database name, the _table_ routines return the table name, and

3579 ** the origin_ routines return the column name.

3580 ** ^The returned string is valid until the [prepared statement] is destroyed

3581 ** using [sqlite3_finalize()] or until the statement is automatically

3582 ** reprepared by the first call to [sqlite3_step()] for a particular run

3583 ** or until the same information is requested

3584 ** again in a different encoding.

3585 **

3586 ** ^The names returned are the original un-aliased names of the

3587 ** database, table, and column.

3588 **

3589 ** ^The first argument to these interfaces is a [prepared statement].

3590 ** ^These functions return information about the Nth result column returned by

3591 ** the statement, where N is the second function argument.

3592 ** ^The left-most column is column 0 for these routines.

3593 **

3594 ** ^If the Nth column returned by the statement is an expression or

3595 ** subquery and is not a column value, then all of these functions return

3596 ** NULL. ^These routine might also return NULL if a memory allocation error

3597 ** occurs. ^Otherwise, they return the name of the attached database, table,

3598 ** or column that query result column was extracted from.

3599 **

3600 ** ^As with all other SQLite APIs, those whose names end with "16" return

3601 ** UTF-16 encoded strings and the other functions return UTF-8.

3602 **

3603 ** ^These APIs are only available if the library was compiled with the

3604 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.

3605 **

3606 ** If two or more threads call one or more of these routines against the same

3607 ** prepared statement and column at the same time then the results are

3608 ** undefined.

3609 **

3610 ** If two or more threads call one or more

3611 ** [sqlite3_column_database_name \| column metadata interfaces]

3612 ** for the same [prepared statement] and result column

3613 ** at the same time then the results are undefined.

3614 */

3615 const char sqlite3_column_database_name(sqlite3_stmt,int);

3616 const void sqlite3_column_database_name16(sqlite3_stmt,int);

3617 const char sqlite3_column_table_name(sqlite3_stmt,int);

3618 const void sqlite3_column_table_name16(sqlite3_stmt,int);

3619 const char sqlite3_column_origin_name(sqlite3_stmt,int);

3620 const void sqlite3_column_origin_name16(sqlite3_stmt,int);

3621

3622 /*

3623 ** CAPI3REF: Declared Datatype Of A Query Result

3624 **

3625 ** ^(The first parameter is a [prepared statement].

3626 ** If this statement is a [SELECT] statement and the Nth column of the

3627 ** returned result set of that [SELECT] is a table column (not an

3628 ** expression or subquery) then the declared type of the table

3629 ** column is returned.)^ ^If the Nth column of the result set is an

3630 ** expression or subquery, then a NULL pointer is returned.

3631 ** ^The returned string is always UTF-8 encoded.

3632 **

3633 ** ^(For example, given the database schema:

3634 **

3635 ** CREATE TABLE t1(c1 VARIANT);

3636 **

3637 ** and the following statement to be compiled:

3638 **

3639 ** SELECT c1 + 1, c1 FROM t1;

3640 **

3641 ** this routine would return the string "VARIANT" for the second result

3642 ** column (i==1), and a NULL pointer for the first result column (i==0).)^

3643 **

3644 ** ^SQLite uses dynamic run-time typing. ^So just because a column

3645 ** is declared to contain a particular type does not mean that the

3646 ** data stored in that column is of the declared type. SQLite is

3647 ** strongly typed, but the typing is dynamic not static. ^Type

3648 ** is associated with individual values, not with the containers

3649 ** used to hold those values.

3650 */

3651 const char sqlite3_column_decltype(sqlite3_stmt,int);

3652 const void sqlite3_column_decltype16(sqlite3_stmt,int);

3653

3654 /*

3655 ** CAPI3REF: Evaluate An SQL Statement

3656 **

3657 ** After a [prepared statement] has been prepared using either

3658 ** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy

3659 ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function

3660 ** must be called one or more times to evaluate the statement.

3661 **

3662 ** The details of the behavior of the sqlite3_step() interface depend

3663 ** on whether the statement was prepared using the newer "v2" interface

3664 ** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy

3665 ** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the

3666 ** new "v2" interface is recommended for new applications but the legacy

3667 ** interface will continue to be supported.

3668 **

3669 ** ^In the legacy interface, the return value will be either [SQLITE_BUSY],

3670 ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].

3671 ** ^With the "v2" interface, any of the other [result codes] or

3672 ** [extended result codes] might be returned as well.

3673 **

3674 ** ^[SQLITE_BUSY] means that the database engine was unable to acquire the

3675 ** database locks it needs to do its job. ^If the statement is a [COMMIT]

3676 ** or occurs outside of an explicit transaction, then you can retry the

3677 ** statement. If the statement is not a [COMMIT] and occurs within an

3678 ** explicit transaction then you should rollback the transaction before

3679 ** continuing.

3680 **

3681 ** ^[SQLITE_DONE] means that the statement has finished executing

3682 ** successfully. sqlite3_step() should not be called again on this virtual

3683 ** machine without first calling [sqlite3_reset()] to reset the virtual

3684 ** machine back to its initial state.

3685 **

3686 ** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]

3687 ** is returned each time a new row of data is ready for processing by the

3688 ** caller. The values may be accessed using the [column access functions].

3689 ** sqlite3_step() is called again to retrieve the next row of data.

3690 **

3691 ** ^[SQLITE_ERROR] means that a run-time error (such as a constraint

3692 ** violation) has occurred. sqlite3_step() should not be called again on

3693 ** the VM. More information may be found by calling [sqlite3_errmsg()].

3694 ** ^With the legacy interface, a more specific error code (for example,

3695 ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)

3696 ** can be obtained by calling [sqlite3_reset()] on the

3697 ** [prepared statement]. ^In the "v2" interface,

3698 ** the more specific error code is returned directly by sqlite3_step().

3699 **

3700 ** [SQLITE_MISUSE] means that the this routine was called inappropriately.

3701 ** Perhaps it was called on a [prepared statement] that has

3702 ** already been [sqlite3_finalize \| finalized] or on one that had

3703 ** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could

3704 ** be the case that the same database connection is being used by two or

3705 ** more threads at the same moment in time.

3706 **

3707 ** For all versions of SQLite up to and including 3.6.23.1, a call to

3708 ** [sqlite3_reset()] was required after sqlite3_step() returned anything

3709 ** other than [SQLITE_ROW] before any subsequent invocation of

3710 ** sqlite3_step(). Failure to reset the prepared statement using

3711 ** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from

3712 ** sqlite3_step(). But after version 3.6.23.1, sqlite3_step() began

3713 ** calling [sqlite3_reset()] automatically in this circumstance rather

3714 ** than returning [SQLITE_MISUSE]. This is not considered a compatibility

3715 ** break because any application that ever receives an SQLITE_MISUSE error

3716 ** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option

3717 ** can be used to restore the legacy behavior.

3718 **

3719 ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()

3720 ** API always returns a generic error code, [SQLITE_ERROR], following any

3721 ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call

3722 ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the

3723 ** specific [error codes] that better describes the error.

3724 ** We admit that this is a goofy design. The problem has been fixed

3725 ** with the "v2" interface. If you prepare all of your SQL statements

3726 ** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead

3727 ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,

3728 ** then the more specific [error codes] are returned directly

3729 ** by sqlite3_step(). The use of the "v2" interface is recommended.

3730 */

3731 int sqlite3_step(sqlite3_stmt*);

3732

3733 /*

3734 ** CAPI3REF: Number of columns in a result set

3735 **

3736 ** ^The sqlite3_data_count(P) interface returns the number of columns in the

3737 ** current row of the result set of [prepared statement] P.

3738 ** ^If prepared statement P does not have results ready to return

3739 ** (via calls to the [sqlite3_column_int \| sqlite3_column_*()] of

3740 ** interfaces) then sqlite3_data_count(P) returns 0.

3741 ** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.

3742 ** ^The sqlite3_data_count(P) routine returns 0 if the previous call to

3743 ** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P)

3744 ** will return non-zero if previous call to [sqlite3_step](P) returned

3745 ** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum]

3746 ** where it always returns zero since each step of that multi-step

3747 ** pragma returns 0 columns of data.

3748 **

3749 ** See also: [sqlite3_column_count()]

3750 */

3751 int sqlite3_data_count(sqlite3_stmt *pStmt);

3752

3753 /*

3754 ** CAPI3REF: Fundamental Datatypes

3755 ** KEYWORDS: SQLITE_TEXT

3756 **

3757 ** ^(Every value in SQLite has one of five fundamental datatypes:

3758 **

3759 ** <ul>

3760 ** <li> 64-bit signed integer

3761 ** <li> 64-bit IEEE floating point number

3762 ** <li> string

3763 ** <li> BLOB

3764 ** <li> NULL

3765 ** </ul>)^

3766 **

3767 ** These constants are codes for each of those types.

3768 **

3769 ** Note that the SQLITE_TEXT constant was also used in SQLite version 2

3770 ** for a completely different meaning. Software that links against both

3771 ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not

3772 ** SQLITE_TEXT.

3773 */

3774 #define SQLITE_INTEGER 1

3775 #define SQLITE_FLOAT 2

3776 #define SQLITE_BLOB 4

3777 #define SQLITE_NULL 5

3778 #ifdef SQLITE_TEXT

3779 # undef SQLITE_TEXT

3780 #else

3781 # define SQLITE_TEXT 3

3782 #endif

3783 #define SQLITE3_TEXT 3

3784

3785 /*

3786 ** CAPI3REF: Result Values From A Query

3787 ** KEYWORDS: {column access functions}

3788 **

3789 ** These routines form the "result set" interface.

3790 **

3791 ** ^These routines return information about a single column of the current

3792 ** result row of a query. ^In every case the first argument is a pointer

3793 ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]

3794 ** that was returned from [sqlite3_prepare_v2()] or one of its variants)

3795 ** and the second argument is the index of the column for which information

3796 ** should be returned. ^The leftmost column of the result set has the index 0.

3797 ** ^The number of columns in the result can be determined using

3798 ** [sqlite3_column_count()].

3799 **

3800 ** If the SQL statement does not currently point to a valid row, or if the

3801 ** column index is out of range, the result is undefined.

3802 ** These routines may only be called when the most recent call to

3803 ** [sqlite3_step()] has returned [SQLITE_ROW] and neither

3804 ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.

3805 ** If any of these routines are called after [sqlite3_reset()] or

3806 ** [sqlite3_finalize()] or after [sqlite3_step()] has returned

3807 ** something other than [SQLITE_ROW], the results are undefined.

3808 ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]

3809 ** are called from a different thread while any of these routines

3810 ** are pending, then the results are undefined.

3811 **

3812 ** ^The sqlite3_column_type() routine returns the

3813 ** [SQLITE_INTEGER \| datatype code] for the initial data type

3814 ** of the result column. ^The returned value is one of [SQLITE_INTEGER],

3815 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value

3816 ** returned by sqlite3_column_type() is only meaningful if no type

3817 ** conversions have occurred as described below. After a type conversion,

3818 ** the value returned by sqlite3_column_type() is undefined. Future

3819 ** versions of SQLite may change the behavior of sqlite3_column_type()

3820 ** following a type conversion.

3821 **

3822 ** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()

3823 ** routine returns the number of bytes in that BLOB or string.

3824 ** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts

3825 ** the string to UTF-8 and then returns the number of bytes.

3826 ** ^If the result is a numeric value then sqlite3_column_bytes() uses

3827 ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns

3828 ** the number of bytes in that string.

3829 ** ^If the result is NULL, then sqlite3_column_bytes() returns zero.

3830 **

3831 ** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()

3832 ** routine returns the number of bytes in that BLOB or string.

3833 ** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts

3834 ** the string to UTF-16 and then returns the number of bytes.

3835 ** ^If the result is a numeric value then sqlite3_column_bytes16() uses

3836 ** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns

3837 ** the number of bytes in that string.

3838 ** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.

3839 **

3840 ** ^The values returned by [sqlite3_column_bytes()] and

3841 ** [sqlite3_column_bytes16()] do not include the zero terminators at the end

3842 ** of the string. ^For clarity: the values returned by

3843 ** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of

3844 ** bytes in the string, not the number of characters.

3845 **

3846 ** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),

3847 ** even empty strings, are always zero-terminated. ^The return

3848 ** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.

3849 **

3850 ** ^The object returned by [sqlite3_column_value()] is an

3851 ** [unprotected sqlite3_value] object. An unprotected sqlite3_value object

3852 ** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()].

3853 ** If the [unprotected sqlite3_value] object returned by

3854 ** [sqlite3_column_value()] is used in any other way, including calls

3855 ** to routines like [sqlite3_value_int()], [sqlite3_value_text()],

3856 ** or [sqlite3_value_bytes()], then the behavior is undefined.

3857 **

3858 ** These routines attempt to convert the value where appropriate. ^For

3859 ** example, if the internal representation is FLOAT and a text result

3860 ** is requested, [sqlite3_snprintf()] is used internally to perform the

3861 ** conversion automatically. ^(The following table details the conversions

3862 ** that are applied:

3863 **

3864 ** <blockquote>

3865 ** <table border="1">

3866 ** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion

3867 **

3868 ** <tr><td> NULL <td> INTEGER <td> Result is 0

3869 ** <tr><td> NULL <td> FLOAT <td> Result is 0.0

3870 ** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer

3871 ** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer

3872 ** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float

3873 ** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer

3874 ** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT

3875 ** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER

3876 ** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float

3877 ** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB

3878 ** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER

3879 ** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL

3880 ** <tr><td> TEXT <td> BLOB <td> No change

3881 ** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER

3882 ** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL

3883 ** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed

3884 ** </table>

3885 ** </blockquote>)^

3886 **

3887 ** The table above makes reference to standard C library functions atoi()

3888 ** and atof(). SQLite does not really use these functions. It has its

3889 ** own equivalent internal routines. The atoi() and atof() names are

3890 ** used in the table for brevity and because they are familiar to most

3891 ** C programmers.

3892 **

3893 ** Note that when type conversions occur, pointers returned by prior

3894 ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or

3895 ** sqlite3_column_text16() may be invalidated.

3896 ** Type conversions and pointer invalidations might occur

3897 ** in the following cases:

3898 **

3899 ** <ul>

3900 ** <li> The initial content is a BLOB and sqlite3_column_text() or

3901 ** sqlite3_column_text16() is called. A zero-terminator might

3902 ** need to be added to the string.</li>

3903 ** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or

3904 ** sqlite3_column_text16() is called. The content must be converted

3905 ** to UTF-16.</li>

3906 ** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or

3907 ** sqlite3_column_text() is called. The content must be converted

3908 ** to UTF-8.</li>

3909 ** </ul>

3910 **

3911 ** ^Conversions between UTF-16be and UTF-16le are always done in place and do

3912 ** not invalidate a prior pointer, though of course the content of the buffer

3913 ** that the prior pointer references will have been modified. Other kinds

3914 ** of conversion are done in place when it is possible, but sometimes they

3915 ** are not possible and in those cases prior pointers are invalidated.

3916 **

3917 ** The safest and easiest to remember policy is to invoke these routines

3918 ** in one of the following ways:

3919 **

3920 ** <ul>

3921 ** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>

3922 ** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>

3923 ** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>

3924 ** </ul>

3925 **

3926 ** In other words, you should call sqlite3_column_text(),

3927 ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result

3928 ** into the desired format, then invoke sqlite3_column_bytes() or

3929 ** sqlite3_column_bytes16() to find the size of the result. Do not mix calls

3930 ** to sqlite3_column_text() or sqlite3_column_blob() with calls to

3931 ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()

3932 ** with calls to sqlite3_column_bytes().

3933 **

3934 ** ^The pointers returned are valid until a type conversion occurs as

3935 ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or

3936 ** [sqlite3_finalize()] is called. ^The memory space used to hold strings

3937 ** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned

3938 ** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into

3939 ** [sqlite3_free()].

3940 **

3941 ** ^(If a memory allocation error occurs during the evaluation of any

3942 ** of these routines, a default value is returned. The default value

3943 ** is either the integer 0, the floating point number 0.0, or a NULL

3944 ** pointer. Subsequent calls to [sqlite3_errcode()] will return

3945 ** [SQLITE_NOMEM].)^

3946 */

3947 const void sqlite3_column_blob(sqlite3_stmt, int iCol);

3948 int sqlite3_column_bytes(sqlite3_stmt*, int iCol);

3949 int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);

3950 double sqlite3_column_double(sqlite3_stmt*, int iCol);

3951 int sqlite3_column_int(sqlite3_stmt*, int iCol);

3952 sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);

3953 const unsigned char sqlite3_column_text(sqlite3_stmt, int iCol);

3954 const void sqlite3_column_text16(sqlite3_stmt, int iCol);

3955 int sqlite3_column_type(sqlite3_stmt*, int iCol);

3956 sqlite3_value sqlite3_column_value(sqlite3_stmt, int iCol);

3957

3958 /*

3959 ** CAPI3REF: Destroy A Prepared Statement Object

3960 **

3961 ** ^The sqlite3_finalize() function is called to delete a [prepared statement].

3962 ** ^If the most recent evaluation of the statement encountered no errors

3963 ** or if the statement is never been evaluated, then sqlite3_finalize() returns

3964 ** SQLITE_OK. ^If the most recent evaluation of statement S failed, then

3965 ** sqlite3_finalize(S) returns the appropriate [error code] or

3966 ** [extended error code].

3967 **

3968 ** ^The sqlite3_finalize(S) routine can be called at any point during

3969 ** the life cycle of [prepared statement] S:

3970 ** before statement S is ever evaluated, after

3971 ** one or more calls to [sqlite3_reset()], or after any call

3972 ** to [sqlite3_step()] regardless of whether or not the statement has

3973 ** completed execution.

3974 **

3975 ** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.

3976 **

3977 ** The application must finalize every [prepared statement] in order to avoid

3978 ** resource leaks. It is a grievous error for the application to try to use

3979 ** a prepared statement after it has been finalized. Any use of a prepared

3980 ** statement after it has been finalized can result in undefined and

3981 ** undesirable behavior such as segfaults and heap corruption.

3982 */

3983 int sqlite3_finalize(sqlite3_stmt *pStmt);

3984

3985 /*

3986 ** CAPI3REF: Reset A Prepared Statement Object

3987 **

3988 ** The sqlite3_reset() function is called to reset a [prepared statement]

3989 ** object back to its initial state, ready to be re-executed.

3990 ** ^Any SQL statement variables that had values bound to them using

3991 ** the [sqlite3_bind_blob \| sqlite3_bind_*() API] retain their values.

3992 ** Use [sqlite3_clear_bindings()] to reset the bindings.

3993 **

3994 ** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S

3995 ** back to the beginning of its program.

3996 **

3997 ** ^If the most recent call to [sqlite3_step(S)] for the

3998 ** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],

3999 ** or if [sqlite3_step(S)] has never before been called on S,

4000 ** then [sqlite3_reset(S)] returns [SQLITE_OK].

4001 **

4002 ** ^If the most recent call to [sqlite3_step(S)] for the

4003 ** [prepared statement] S indicated an error, then

4004 ** [sqlite3_reset(S)] returns an appropriate [error code].

4005 **

4006 ** ^The [sqlite3_reset(S)] interface does not change the values

4007 ** of any [sqlite3_bind_blob\|bindings] on the [prepared statement] S.

4008 */

4009 int sqlite3_reset(sqlite3_stmt *pStmt);

4010

4011 /*

4012 ** CAPI3REF: Create Or Redefine SQL Functions

4013 ** KEYWORDS: {function creation routines}

4014 ** KEYWORDS: {application-defined SQL function}

4015 ** KEYWORDS: {application-defined SQL functions}

4016 **

4017 ** ^These functions (collectively known as "function creation routines")

4018 ** are used to add SQL functions or aggregates or to redefine the behavior

4019 ** of existing SQL functions or aggregates. The only differences between

4020 ** these routines are the text encoding expected for

4021 ** the second parameter (the name of the function being created)

4022 ** and the presence or absence of a destructor callback for

4023 ** the application data pointer.

4024 **

4025 ** ^The first parameter is the [database connection] to which the SQL

4026 ** function is to be added. ^If an application uses more than one database

4027 ** connection then application-defined SQL functions must be added

4028 ** to each database connection separately.

4029 **

4030 ** ^The second parameter is the name of the SQL function to be created or

4031 ** redefined. ^The length of the name is limited to 255 bytes in a UTF-8

4032 ** representation, exclusive of the zero-terminator. ^Note that the name

4033 ** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.

4034 ** ^Any attempt to create a function with a longer name

4035 ** will result in [SQLITE_MISUSE] being returned.

4036 **

4037 ** ^The third parameter (nArg)

4038 ** is the number of arguments that the SQL function or

4039 ** aggregate takes. ^If this parameter is -1, then the SQL function or

4040 ** aggregate may take any number of arguments between 0 and the limit

4041 ** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third

4042 ** parameter is less than -1 or greater than 127 then the behavior is

4043 ** undefined.

4044 **

4045 ** ^The fourth parameter, eTextRep, specifies what

4046 ** [SQLITE_UTF8 \| text encoding] this SQL function prefers for

4047 ** its parameters. The application should set this parameter to

4048 ** [SQLITE_UTF16LE] if the function implementation invokes

4049 ** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the

4050 ** implementation invokes [sqlite3_value_text16be()] on an input, or

4051 ** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8]

4052 ** otherwise. ^The same SQL function may be registered multiple times using

4053 ** different preferred text encodings, with different implementations for

4054 ** each encoding.

4055 ** ^When multiple implementations of the same function are available, SQLite

4056 ** will pick the one that involves the least amount of data conversion.

4057 **

4058 ** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC]

4059 ** to signal that the function will always return the same result given

4060 ** the same inputs within a single SQL statement. Most SQL functions are

4061 ** deterministic. The built-in [random()] SQL function is an example of a

4062 ** function that is not deterministic. The SQLite query planner is able to

4063 ** perform additional optimizations on deterministic functions, so use

4064 ** of the [SQLITE_DETERMINISTIC] flag is recommended where possible.

4065 **

4066 ** ^(The fifth parameter is an arbitrary pointer. The implementation of the

4067 ** function can gain access to this pointer using [sqlite3_user_data()].)^

4068 **

4069 ** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are

4070 ** pointers to C-language functions that implement the SQL function or

4071 ** aggregate. ^A scalar SQL function requires an implementation of the xFunc

4072 ** callback only; NULL pointers must be passed as the xStep and xFinal

4073 ** parameters. ^An aggregate SQL function requires an implementation of xStep

4074 ** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing

4075 ** SQL function or aggregate, pass NULL pointers for all three function

4076 ** callbacks.

4077 **

4078 ** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL,

4079 ** then it is destructor for the application data pointer.

4080 ** The destructor is invoked when the function is deleted, either by being

4081 ** overloaded or when the database connection closes.)^

4082 ** ^The destructor is also invoked if the call to

4083 ** sqlite3_create_function_v2() fails.

4084 ** ^When the destructor callback of the tenth parameter is invoked, it

4085 ** is passed a single argument which is a copy of the application data

4086 ** pointer which was the fifth parameter to sqlite3_create_function_v2().

4087 **

4088 ** ^It is permitted to register multiple implementations of the same

4089 ** functions with the same name but with either differing numbers of

4090 ** arguments or differing preferred text encodings. ^SQLite will use

4091 ** the implementation that most closely matches the way in which the

4092 ** SQL function is used. ^A function implementation with a non-negative

4093 ** nArg parameter is a better match than a function implementation with

4094 ** a negative nArg. ^A function where the preferred text encoding

4095 ** matches the database encoding is a better

4096 ** match than a function where the encoding is different.

4097 ** ^A function where the encoding difference is between UTF16le and UTF16be

4098 ** is a closer match than a function where the encoding difference is

4099 ** between UTF8 and UTF16.

4100 **

4101 ** ^Built-in functions may be overloaded by new application-defined functions.

4102 **

4103 ** ^An application-defined function is permitted to call other

4104 ** SQLite interfaces. However, such calls must not

4105 ** close the database connection nor finalize or reset the prepared

4106 ** statement in which the function is running.

4107 */

4108 int sqlite3_create_function(

4109 sqlite3 *db,

4110 const char *zFunctionName,

4111 int nArg,

4112 int eTextRep,

4113 void *pApp,

4114 void (xFunc)(sqlite3_context,int,sqlite3_value**),

4115 void (xStep)(sqlite3_context,int,sqlite3_value**),

4116 void (xFinal)(sqlite3_context)

4117 );

4118 int sqlite3_create_function16(

4119 sqlite3 *db,

4120 const void *zFunctionName,

4121 int nArg,

4122 int eTextRep,

4123 void *pApp,

4124 void (xFunc)(sqlite3_context,int,sqlite3_value**),

4125 void (xStep)(sqlite3_context,int,sqlite3_value**),

4126 void (xFinal)(sqlite3_context)

4127 );

4128 int sqlite3_create_function_v2(

4129 sqlite3 *db,

4130 const char *zFunctionName,

4131 int nArg,

4132 int eTextRep,

4133 void *pApp,

4134 void (xFunc)(sqlite3_context,int,sqlite3_value**),

4135 void (xStep)(sqlite3_context,int,sqlite3_value**),

4136 void (xFinal)(sqlite3_context),

4137 void(xDestroy)(void)

4138 );

4139

4140 /*

4141 ** CAPI3REF: Text Encodings

4142 **

4143 ** These constant define integer codes that represent the various

4144 ** text encodings supported by SQLite.

4145 */

4146 #define SQLITE_UTF8 1

4147 #define SQLITE_UTF16LE 2

4148 #define SQLITE_UTF16BE 3

4149 #define SQLITE_UTF16 4 /* Use native byte order */

4150 #define SQLITE_ANY 5 /* Deprecated */

4151 #define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */

4152

4153 /*

4154 ** CAPI3REF: Function Flags

4155 **

4156 ** These constants may be ORed together with the

4157 ** [SQLITE_UTF8 \| preferred text encoding] as the fourth argument

4158 ** to [sqlite3_create_function()], [sqlite3_create_function16()], or

4159 ** [sqlite3_create_function_v2()].

4160 */

4161 #define SQLITE_DETERMINISTIC 0x800

4162

4163 /*

4164 ** CAPI3REF: Deprecated Functions

4165 ** DEPRECATED

4166 **

4167 ** These functions are [deprecated]. In order to maintain

4168 ** backwards compatibility with older code, these functions continue

4169 ** to be supported. However, new applications should avoid

4170 ** the use of these functions. To help encourage people to avoid

4171 ** using these functions, we are not going to tell you what they do.

4172 */

4173 #ifndef SQLITE_OMIT_DEPRECATED

4174 SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);

4175 SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);

4176 SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt, sqlite3_stmt);

4177 SQLITE_DEPRECATED int sqlite3_global_recover(void);

4178 SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);

4179 SQLITE_DEPRECATED int sqlite3_memory_alarm(void()(void,sqlite3_int64,int),

4180 void*,sqlite3_int64);

4181 #endif

4182

4183 /*

4184 ** CAPI3REF: Obtaining SQL Function Parameter Values

4185 **

4186 ** The C-language implementation of SQL functions and aggregates uses

4187 ** this set of interface routines to access the parameter values on

4188 ** the function or aggregate.

4189 **

4190 ** The xFunc (for scalar functions) or xStep (for aggregates) parameters

4191 ** to [sqlite3_create_function()] and [sqlite3_create_function16()]

4192 ** define callbacks that implement the SQL functions and aggregates.

4193 ** The 3rd parameter to these callbacks is an array of pointers to

4194 ** [protected sqlite3_value] objects. There is one [sqlite3_value] object for

4195 ** each parameter to the SQL function. These routines are used to

4196 ** extract values from the [sqlite3_value] objects.

4197 **

4198 ** These routines work only with [protected sqlite3_value] objects.

4199 ** Any attempt to use these routines on an [unprotected sqlite3_value]

4200 ** object results in undefined behavior.

4201 **

4202 ** ^These routines work just like the corresponding [column access functions]

4203 ** except that these routines take a single [protected sqlite3_value] object

4204 ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.

4205 **

4206 ** ^The sqlite3_value_text16() interface extracts a UTF-16 string

4207 ** in the native byte-order of the host machine. ^The

4208 ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces

4209 ** extract UTF-16 strings as big-endian and little-endian respectively.

4210 **

4211 ** ^(The sqlite3_value_numeric_type() interface attempts to apply

4212 ** numeric affinity to the value. This means that an attempt is

4213 ** made to convert the value to an integer or floating point. If

4214 ** such a conversion is possible without loss of information (in other

4215 ** words, if the value is a string that looks like a number)

4216 ** then the conversion is performed. Otherwise no conversion occurs.

4217 ** The [SQLITE_INTEGER \| datatype] after conversion is returned.)^

4218 **

4219 ** Please pay particular attention to the fact that the pointer returned

4220 ** from [sqlite3_value_blob()], [sqlite3_value_text()], or

4221 ** [sqlite3_value_text16()] can be invalidated by a subsequent call to

4222 ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],

4223 ** or [sqlite3_value_text16()].

4224 **

4225 ** These routines must be called from the same thread as

4226 ** the SQL function that supplied the [sqlite3_value*] parameters.

4227 */

4228 const void sqlite3_value_blob(sqlite3_value);

4229 int sqlite3_value_bytes(sqlite3_value*);

4230 int sqlite3_value_bytes16(sqlite3_value*);

4231 double sqlite3_value_double(sqlite3_value*);

4232 int sqlite3_value_int(sqlite3_value*);

4233 sqlite3_int64 sqlite3_value_int64(sqlite3_value*);

4234 const unsigned char sqlite3_value_text(sqlite3_value);

4235 const void sqlite3_value_text16(sqlite3_value);

4236 const void sqlite3_value_text16le(sqlite3_value);

4237 const void sqlite3_value_text16be(sqlite3_value);

4238 int sqlite3_value_type(sqlite3_value*);

4239 int sqlite3_value_numeric_type(sqlite3_value*);

4240

4241 /*

4242 ** CAPI3REF: Obtain Aggregate Function Context

4243 **

4244 ** Implementations of aggregate SQL functions use this

4245 ** routine to allocate memory for storing their state.

4246 **

4247 ** ^The first time the sqlite3_aggregate_context(C,N) routine is called

4248 ** for a particular aggregate function, SQLite

4249 ** allocates N of memory, zeroes out that memory, and returns a pointer

4250 ** to the new memory. ^On second and subsequent calls to

4251 ** sqlite3_aggregate_context() for the same aggregate function instance,

4252 ** the same buffer is returned. Sqlite3_aggregate_context() is normally

4253 ** called once for each invocation of the xStep callback and then one

4254 ** last time when the xFinal callback is invoked. ^(When no rows match

4255 ** an aggregate query, the xStep() callback of the aggregate function

4256 ** implementation is never called and xFinal() is called exactly once.

4257 ** In those cases, sqlite3_aggregate_context() might be called for the

4258 ** first time from within xFinal().)^

4259 **

4260 ** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer

4261 ** when first called if N is less than or equal to zero or if a memory

4262 ** allocate error occurs.

4263 **

4264 ** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is

4265 ** determined by the N parameter on first successful call. Changing the

4266 ** value of N in subsequent call to sqlite3_aggregate_context() within

4267 ** the same aggregate function instance will not resize the memory

4268 ** allocation.)^ Within the xFinal callback, it is customary to set

4269 ** N=0 in calls to sqlite3_aggregate_context(C,N) so that no

4270 ** pointless memory allocations occur.

4271 **

4272 ** ^SQLite automatically frees the memory allocated by

4273 ** sqlite3_aggregate_context() when the aggregate query concludes.

4274 **

4275 ** The first parameter must be a copy of the

4276 ** [sqlite3_context \| SQL function context] that is the first parameter

4277 ** to the xStep or xFinal callback routine that implements the aggregate

4278 ** function.

4279 **

4280 ** This routine must be called from the same thread in which

4281 ** the aggregate SQL function is running.

4282 */

4283 void sqlite3_aggregate_context(sqlite3_context, int nBytes);

4284

4285 /*

4286 ** CAPI3REF: User Data For Functions

4287 **

4288 ** ^The sqlite3_user_data() interface returns a copy of

4289 ** the pointer that was the pUserData parameter (the 5th parameter)

4290 ** of the [sqlite3_create_function()]

4291 ** and [sqlite3_create_function16()] routines that originally

4292 ** registered the application defined function.

4293 **

4294 ** This routine must be called from the same thread in which

4295 ** the application-defined function is running.

4296 */

4297 void sqlite3_user_data(sqlite3_context);

4298

4299 /*

4300 ** CAPI3REF: Database Connection For Functions

4301 **

4302 ** ^The sqlite3_context_db_handle() interface returns a copy of

4303 ** the pointer to the [database connection] (the 1st parameter)

4304 ** of the [sqlite3_create_function()]

4305 ** and [sqlite3_create_function16()] routines that originally

4306 ** registered the application defined function.

4307 */

4308 sqlite3 sqlite3_context_db_handle(sqlite3_context);

4309

4310 /*

4311 ** CAPI3REF: Function Auxiliary Data

4312 **

4313 ** These functions may be used by (non-aggregate) SQL functions to

4314 ** associate metadata with argument values. If the same value is passed to

4315 ** multiple invocations of the same SQL function during query execution, under

4316 ** some circumstances the associated metadata may be preserved. An example

4317 ** of where this might be useful is in a regular-expression matching

4318 ** function. The compiled version of the regular expression can be stored as

4319 ** metadata associated with the pattern string.

4320 ** Then as long as the pattern string remains the same,

4321 ** the compiled regular expression can be reused on multiple

4322 ** invocations of the same function.

4323 **

4324 ** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata

4325 ** associated by the sqlite3_set_auxdata() function with the Nth argument

4326 ** value to the application-defined function. ^If there is no metadata

4327 ** associated with the function argument, this sqlite3_get_auxdata() interface

4328 ** returns a NULL pointer.

4329 **

4330 ** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th

4331 ** argument of the application-defined function. ^Subsequent

4332 ** calls to sqlite3_get_auxdata(C,N) return P from the most recent

4333 ** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or

4334 ** NULL if the metadata has been discarded.

4335 ** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL,

4336 ** SQLite will invoke the destructor function X with parameter P exactly

4337 ** once, when the metadata is discarded.

4338 ** SQLite is free to discard the metadata at any time, including: <ul>

4339 ** <li> when the corresponding function parameter changes, or

4340 ** <li> when [sqlite3_reset()] or [sqlite3_finalize()] is called for the

4341 ** SQL statement, or

4342 ** <li> when sqlite3_set_auxdata() is invoked again on the same parameter, or

4343 ** <li> during the original sqlite3_set_auxdata() call when a memory

4344 ** allocation error occurs. </ul>)^

4345 **

4346 ** Note the last bullet in particular. The destructor X in

4347 ** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the

4348 ** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata()

4349 ** should be called near the end of the function implementation and the

4350 ** function implementation should not make any use of P after

4351 ** sqlite3_set_auxdata() has been called.

4352 **

4353 ** ^(In practice, metadata is preserved between function calls for

4354 ** function parameters that are compile-time constants, including literal

4355 ** values and [parameters] and expressions composed from the same.)^

4356 **

4357 ** These routines must be called from the same thread in which

4358 ** the SQL function is running.

4359 */

4360 void sqlite3_get_auxdata(sqlite3_context, int N);

4361 void sqlite3_set_auxdata(sqlite3_context, int N, void, void ()(void));

4362

4363

4364 /*

4365 ** CAPI3REF: Constants Defining Special Destructor Behavior

4366 **

4367 ** These are special values for the destructor that is passed in as the

4368 ** final argument to routines like [sqlite3_result_blob()]. ^If the destructor

4369 ** argument is SQLITE_STATIC, it means that the content pointer is constant

4370 ** and will never change. It does not need to be destroyed. ^The

4371 ** SQLITE_TRANSIENT value means that the content will likely change in

4372 ** the near future and that SQLite should make its own private copy of

4373 ** the content before returning.

4374 **

4375 ** The typedef is necessary to work around problems in certain

4376 ** C++ compilers.

4377 */

4378 typedef void (sqlite3_destructor_type)(void);

4379 #define SQLITE_STATIC ((sqlite3_destructor_type)0)

4380 #define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1)

4381

4382 /*

4383 ** CAPI3REF: Setting The Result Of An SQL Function

4384 **

4385 ** These routines are used by the xFunc or xFinal callbacks that

4386 ** implement SQL functions and aggregates. See

4387 ** [sqlite3_create_function()] and [sqlite3_create_function16()]

4388 ** for additional information.

4389 **

4390 ** These functions work very much like the [parameter binding] family of

4391 ** functions used to bind values to host parameters in prepared statements.

4392 ** Refer to the [SQL parameter] documentation for additional information.

4393 **

4394 ** ^The sqlite3_result_blob() interface sets the result from

4395 ** an application-defined function to be the BLOB whose content is pointed

4396 ** to by the second parameter and which is N bytes long where N is the

4397 ** third parameter.

4398 **

4399 ** ^The sqlite3_result_zeroblob() interfaces set the result of

4400 ** the application-defined function to be a BLOB containing all zero

4401 ** bytes and N bytes in size, where N is the value of the 2nd parameter.

4402 **

4403 ** ^The sqlite3_result_double() interface sets the result from

4404 ** an application-defined function to be a floating point value specified

4405 ** by its 2nd argument.

4406 **

4407 ** ^The sqlite3_result_error() and sqlite3_result_error16() functions

4408 ** cause the implemented SQL function to throw an exception.

4409 ** ^SQLite uses the string pointed to by the

4410 ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()

4411 ** as the text of an error message. ^SQLite interprets the error

4412 ** message string from sqlite3_result_error() as UTF-8. ^SQLite

4413 ** interprets the string from sqlite3_result_error16() as UTF-16 in native

4414 ** byte order. ^If the third parameter to sqlite3_result_error()

4415 ** or sqlite3_result_error16() is negative then SQLite takes as the error

4416 ** message all text up through the first zero character.

4417 ** ^If the third parameter to sqlite3_result_error() or

4418 ** sqlite3_result_error16() is non-negative then SQLite takes that many

4419 ** bytes (not characters) from the 2nd parameter as the error message.

4420 ** ^The sqlite3_result_error() and sqlite3_result_error16()

4421 ** routines make a private copy of the error message text before

4422 ** they return. Hence, the calling function can deallocate or

4423 ** modify the text after they return without harm.

4424 ** ^The sqlite3_result_error_code() function changes the error code

4425 ** returned by SQLite as a result of an error in a function. ^By default,

4426 ** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error()

4427 ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.

4428 **

4429 ** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an

4430 ** error indicating that a string or BLOB is too long to represent.

4431 **

4432 ** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an

4433 ** error indicating that a memory allocation failed.

4434 **

4435 ** ^The sqlite3_result_int() interface sets the return value

4436 ** of the application-defined function to be the 32-bit signed integer

4437 ** value given in the 2nd argument.

4438 ** ^The sqlite3_result_int64() interface sets the return value

4439 ** of the application-defined function to be the 64-bit signed integer

4440 ** value given in the 2nd argument.

4441 **

4442 ** ^The sqlite3_result_null() interface sets the return value

4443 ** of the application-defined function to be NULL.

4444 **

4445 ** ^The sqlite3_result_text(), sqlite3_result_text16(),

4446 ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces

4447 ** set the return value of the application-defined function to be

4448 ** a text string which is represented as UTF-8, UTF-16 native byte order,

4449 ** UTF-16 little endian, or UTF-16 big endian, respectively.

4450 ** ^The sqlite3_result_text64() interface sets the return value of an

4451 ** application-defined function to be a text string in an encoding

4452 ** specified by the fifth (and last) parameter, which must be one

4453 ** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE].

4454 ** ^SQLite takes the text result from the application from

4455 ** the 2nd parameter of the sqlite3_result_text* interfaces.

4456 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces

4457 ** is negative, then SQLite takes result text from the 2nd parameter

4458 ** through the first zero character.

4459 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces

4460 ** is non-negative, then as many bytes (not characters) of the text

4461 ** pointed to by the 2nd parameter are taken as the application-defined

4462 ** function result. If the 3rd parameter is non-negative, then it

4463 ** must be the byte offset into the string where the NUL terminator would

4464 ** appear if the string where NUL terminated. If any NUL characters occur

4465 ** in the string at a byte offset that is less than the value of the 3rd

4466 ** parameter, then the resulting string will contain embedded NULs and the

4467 ** result of expressions operating on strings with embedded NULs is undefined.

4468 ** ^If the 4th parameter to the sqlite3_result_text* interfaces

4469 ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that

4470 ** function as the destructor on the text or BLOB result when it has

4471 ** finished using that result.

4472 ** ^If the 4th parameter to the sqlite3_result_text* interfaces or to

4473 ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite

4474 ** assumes that the text or BLOB result is in constant space and does not

4475 ** copy the content of the parameter nor call a destructor on the content

4476 ** when it has finished using that result.

4477 ** ^If the 4th parameter to the sqlite3_result_text* interfaces

4478 ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT

4479 ** then SQLite makes a copy of the result into space obtained from

4480 ** from [sqlite3_malloc()] before it returns.

4481 **

4482 ** ^The sqlite3_result_value() interface sets the result of

4483 ** the application-defined function to be a copy the

4484 ** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The

4485 ** sqlite3_result_value() interface makes a copy of the [sqlite3_value]

4486 ** so that the [sqlite3_value] specified in the parameter may change or

4487 ** be deallocated after sqlite3_result_value() returns without harm.

4488 ** ^A [protected sqlite3_value] object may always be used where an

4489 ** [unprotected sqlite3_value] object is required, so either

4490 ** kind of [sqlite3_value] object can be used with this interface.

4491 **

4492 ** If these routines are called from within the different thread

4493 ** than the one containing the application-defined function that received

4494 ** the [sqlite3_context] pointer, the results are undefined.

4495 */

4496 void sqlite3_result_blob(sqlite3_context, const void, int, void()(void));

4497 void sqlite3_result_blob64(sqlite3_context,const void,sqlite3_uint64,void()(v oid));

4498 void sqlite3_result_double(sqlite3_context*, double);

4499 void sqlite3_result_error(sqlite3_context, const char, int);

4500 void sqlite3_result_error16(sqlite3_context, const void, int);

4501 void sqlite3_result_error_toobig(sqlite3_context*);

4502 void sqlite3_result_error_nomem(sqlite3_context*);

4503 void sqlite3_result_error_code(sqlite3_context*, int);

4504 void sqlite3_result_int(sqlite3_context*, int);

4505 void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);

4506 void sqlite3_result_null(sqlite3_context*);

4507 void sqlite3_result_text(sqlite3_context, const char, int, void()(void));

4508 void sqlite3_result_text64(sqlite3_context, const char,sqlite3_uint64,

4509 void()(void), unsigned char encoding);

4510 void sqlite3_result_text16(sqlite3_context, const void, int, void()(void));

4511 void sqlite3_result_text16le(sqlite3_context, const void, int,void()(void));

4512 void sqlite3_result_text16be(sqlite3_context, const void, int,void()(void));

4513 void sqlite3_result_value(sqlite3_context, sqlite3_value);

4514 void sqlite3_result_zeroblob(sqlite3_context*, int n);

4515

4516 /*

4517 ** CAPI3REF: Define New Collating Sequences

4518 **

4519 ** ^These functions add, remove, or modify a [collation] associated

4520 ** with the [database connection] specified as the first argument.

4521 **

4522 ** ^The name of the collation is a UTF-8 string

4523 ** for sqlite3_create_collation() and sqlite3_create_collation_v2()

4524 ** and a UTF-16 string in native byte order for sqlite3_create_collation16().

4525 ** ^Collation names that compare equal according to [sqlite3_strnicmp()] are

4526 ** considered to be the same name.

4527 **

4528 ** ^(The third argument (eTextRep) must be one of the constants:

4529 ** <ul>

4530 ** <li> [SQLITE_UTF8],

4531 ** <li> [SQLITE_UTF16LE],

4532 ** <li> [SQLITE_UTF16BE],

4533 ** <li> [SQLITE_UTF16], or

4534 ** <li> [SQLITE_UTF16_ALIGNED].

4535 ** </ul>)^

4536 ** ^The eTextRep argument determines the encoding of strings passed

4537 ** to the collating function callback, xCallback.

4538 ** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep

4539 ** force strings to be UTF16 with native byte order.

4540 ** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin

4541 ** on an even byte address.

4542 **

4543 ** ^The fourth argument, pArg, is an application data pointer that is passed

4544 ** through as the first argument to the collating function callback.

4545 **

4546 ** ^The fifth argument, xCallback, is a pointer to the collating function.

4547 ** ^Multiple collating functions can be registered using the same name but

4548 ** with different eTextRep parameters and SQLite will use whichever

4549 ** function requires the least amount of data transformation.

4550 ** ^If the xCallback argument is NULL then the collating function is

4551 ** deleted. ^When all collating functions having the same name are deleted,

4552 ** that collation is no longer usable.

4553 **

4554 ** ^The collating function callback is invoked with a copy of the pArg

4555 ** application data pointer and with two strings in the encoding specified

4556 ** by the eTextRep argument. The collating function must return an

4557 ** integer that is negative, zero, or positive

4558 ** if the first string is less than, equal to, or greater than the second,

4559 ** respectively. A collating function must always return the same answer

4560 ** given the same inputs. If two or more collating functions are registered

4561 ** to the same collation name (using different eTextRep values) then all

4562 ** must give an equivalent answer when invoked with equivalent strings.

4563 ** The collating function must obey the following properties for all

4564 ** strings A, B, and C:

4565 **

4566 ** <ol>

4567 ** <li> If A==B then B==A.

4568 ** <li> If A==B and B==C then A==C.

4569 ** <li> If A<B THEN B>A.

4570 ** <li> If A<B and B<C then A<C.

4571 ** </ol>

4572 **

4573 ** If a collating function fails any of the above constraints and that

4574 ** collating function is registered and used, then the behavior of SQLite

4575 ** is undefined.

4576 **

4577 ** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()

4578 ** with the addition that the xDestroy callback is invoked on pArg when

4579 ** the collating function is deleted.

4580 ** ^Collating functions are deleted when they are overridden by later

4581 ** calls to the collation creation functions or when the

4582 ** [database connection] is closed using [sqlite3_close()].

4583 **

4584 ** ^The xDestroy callback is <u>not</u> called if the

4585 ** sqlite3_create_collation_v2() function fails. Applications that invoke

4586 ** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should

4587 ** check the return code and dispose of the application data pointer

4588 ** themselves rather than expecting SQLite to deal with it for them.

4589 ** This is different from every other SQLite interface. The inconsistency

4590 ** is unfortunate but cannot be changed without breaking backwards

4591 ** compatibility.

4592 **

4593 ** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].

4594 */

4595 int sqlite3_create_collation(

4596 sqlite3*,

4597 const char *zName,

4598 int eTextRep,

4599 void *pArg,

4600 int(xCompare)(void,int,const void,int,const void)

4601 );

4602 int sqlite3_create_collation_v2(

4603 sqlite3*,

4604 const char *zName,

4605 int eTextRep,

4606 void *pArg,

4607 int(xCompare)(void,int,const void,int,const void),

4608 void(xDestroy)(void)

4609 );

4610 int sqlite3_create_collation16(

4611 sqlite3*,

4612 const void *zName,

4613 int eTextRep,

4614 void *pArg,

4615 int(xCompare)(void,int,const void,int,const void)

4616 );

4617

4618 /*

4619 ** CAPI3REF: Collation Needed Callbacks

4620 **

4621 ** ^To avoid having to register all collation sequences before a database

4622 ** can be used, a single callback function may be registered with the

4623 ** [database connection] to be invoked whenever an undefined collation

4624 ** sequence is required.

4625 **

4626 ** ^If the function is registered using the sqlite3_collation_needed() API,

4627 ** then it is passed the names of undefined collation sequences as strings

4628 ** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,

4629 ** the names are passed as UTF-16 in machine native byte order.

4630 ** ^A call to either function replaces the existing collation-needed callback.

4631 **

4632 ** ^(When the callback is invoked, the first argument passed is a copy

4633 ** of the second argument to sqlite3_collation_needed() or

4634 ** sqlite3_collation_needed16(). The second argument is the database

4635 ** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],

4636 ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation

4637 ** sequence function required. The fourth parameter is the name of the

4638 ** required collation sequence.)^

4639 **

4640 ** The callback function should register the desired collation using

4641 ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or

4642 ** [sqlite3_create_collation_v2()].

4643 */

4644 int sqlite3_collation_needed(

4645 sqlite3*,

4646 void*,

4647 void()(void,sqlite3,int eTextRep,const char)

4648 );

4649 int sqlite3_collation_needed16(

4650 sqlite3*,

4651 void*,

4652 void()(void,sqlite3,int eTextRep,const void)

4653 );

4654

4655 #ifdef SQLITE_HAS_CODEC

4656 /*

4657 ** Specify the key for an encrypted database. This routine should be

4658 ** called right after sqlite3_open().

4659 **

4660 ** The code to implement this API is not available in the public release

4661 ** of SQLite.

4662 */

4663 int sqlite3_key(

4664 sqlite3 db, / Database to be rekeyed */

4665 const void pKey, int nKey / The key */

4666 );

4667 int sqlite3_key_v2(

4668 sqlite3 db, / Database to be rekeyed */

4669 const char zDbName, / Name of the database */

4670 const void pKey, int nKey / The key */

4671 );

4672

4673 /*

4674 ** Change the key on an open database. If the current database is not

4675 ** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the

4676 ** database is decrypted.

4677 **

4678 ** The code to implement this API is not available in the public release

4679 ** of SQLite.

4680 */

4681 int sqlite3_rekey(

4682 sqlite3 db, / Database to be rekeyed */

4683 const void pKey, int nKey / The new key */

4684 );

4685 int sqlite3_rekey_v2(

4686 sqlite3 db, / Database to be rekeyed */

4687 const char zDbName, / Name of the database */

4688 const void pKey, int nKey / The new key */

4689 );

4690

4691 /*

4692 ** Specify the activation key for a SEE database. Unless

4693 ** activated, none of the SEE routines will work.

4694 */

4695 void sqlite3_activate_see(

4696 const char zPassPhrase / Activation phrase */

4697 );

4698 #endif

4699

4700 #ifdef SQLITE_ENABLE_CEROD

4701 /*

4702 ** Specify the activation key for a CEROD database. Unless

4703 ** activated, none of the CEROD routines will work.

4704 */

4705 void sqlite3_activate_cerod(

4706 const char zPassPhrase / Activation phrase */

4707 );

4708 #endif

4709

4710 /*

4711 ** CAPI3REF: Suspend Execution For A Short Time

4712 **

4713 ** The sqlite3_sleep() function causes the current thread to suspend execution

4714 ** for at least a number of milliseconds specified in its parameter.

4715 **

4716 ** If the operating system does not support sleep requests with

4717 ** millisecond time resolution, then the time will be rounded up to

4718 ** the nearest second. The number of milliseconds of sleep actually

4719 ** requested from the operating system is returned.

4720 **

4721 ** ^SQLite implements this interface by calling the xSleep()

4722 ** method of the default [sqlite3_vfs] object. If the xSleep() method

4723 ** of the default VFS is not implemented correctly, or not implemented at

4724 ** all, then the behavior of sqlite3_sleep() may deviate from the description

4725 ** in the previous paragraphs.

4726 */

4727 int sqlite3_sleep(int);

4728

4729 /*

4730 ** CAPI3REF: Name Of The Folder Holding Temporary Files

4731 **

4732 ** ^(If this global variable is made to point to a string which is

4733 ** the name of a folder (a.k.a. directory), then all temporary files

4734 ** created by SQLite when using a built-in [sqlite3_vfs \| VFS]

4735 ** will be placed in that directory.)^ ^If this variable

4736 ** is a NULL pointer, then SQLite performs a search for an appropriate

4737 ** temporary file directory.

4738 **

4739 ** Applications are strongly discouraged from using this global variable.

4740 ** It is required to set a temporary folder on Windows Runtime (WinRT).

4741 ** But for all other platforms, it is highly recommended that applications

4742 ** neither read nor write this variable. This global variable is a relic

4743 ** that exists for backwards compatibility of legacy applications and should

4744 ** be avoided in new projects.

4745 **

4746 ** It is not safe to read or modify this variable in more than one

4747 ** thread at a time. It is not safe to read or modify this variable

4748 ** if a [database connection] is being used at the same time in a separate

4749 ** thread.

4750 ** It is intended that this variable be set once

4751 ** as part of process initialization and before any SQLite interface

4752 ** routines have been called and that this variable remain unchanged

4753 ** thereafter.

4754 **

4755 ** ^The [temp_store_directory pragma] may modify this variable and cause

4756 ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,

4757 ** the [temp_store_directory pragma] always assumes that any string

4758 ** that this variable points to is held in memory obtained from

4759 ** [sqlite3_malloc] and the pragma may attempt to free that memory

4760 ** using [sqlite3_free].

4761 ** Hence, if this variable is modified directly, either it should be

4762 ** made NULL or made to point to memory obtained from [sqlite3_malloc]

4763 ** or else the use of the [temp_store_directory pragma] should be avoided.

4764 ** Except when requested by the [temp_store_directory pragma], SQLite

4765 ** does not free the memory that sqlite3_temp_directory points to. If

4766 ** the application wants that memory to be freed, it must do

4767 ** so itself, taking care to only do so after all [database connection]

4768 ** objects have been destroyed.

4769 **

4770 ** <b>Note to Windows Runtime users:</b> The temporary directory must be set

4771 ** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various

4772 ** features that require the use of temporary files may fail. Here is an

4773 ** example of how to do this using C++ with the Windows Runtime:

4774 **

4775 ** <blockquote><pre>

4776 ** LPCWSTR zPath = Windows::Storage::ApplicationData::Current->

4777 **   TemporaryFolder->Path->Data();

4778 ** char zPathBuf[MAX_PATH + 1];

4779 ** memset(zPathBuf, 0, sizeof(zPathBuf));

4780 ** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),

4781 **   NULL, NULL);

4782 ** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);

4783 ** </pre></blockquote>

4784 */

4785 SQLITE_EXTERN char *sqlite3_temp_directory;

4786

4787 /*

4788 ** CAPI3REF: Name Of The Folder Holding Database Files

4789 **

4790 ** ^(If this global variable is made to point to a string which is

4791 ** the name of a folder (a.k.a. directory), then all database files

4792 ** specified with a relative pathname and created or accessed by

4793 ** SQLite when using a built-in windows [sqlite3_vfs \| VFS] will be assumed

4794 ** to be relative to that directory.)^ ^If this variable is a NULL

4795 ** pointer, then SQLite assumes that all database files specified

4796 ** with a relative pathname are relative to the current directory

4797 ** for the process. Only the windows VFS makes use of this global

4798 ** variable; it is ignored by the unix VFS.

4799 **

4800 ** Changing the value of this variable while a database connection is

4801 ** open can result in a corrupt database.

4802 **

4803 ** It is not safe to read or modify this variable in more than one

4804 ** thread at a time. It is not safe to read or modify this variable

4805 ** if a [database connection] is being used at the same time in a separate

4806 ** thread.

4807 ** It is intended that this variable be set once

4808 ** as part of process initialization and before any SQLite interface

4809 ** routines have been called and that this variable remain unchanged

4810 ** thereafter.

4811 **

4812 ** ^The [data_store_directory pragma] may modify this variable and cause

4813 ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,

4814 ** the [data_store_directory pragma] always assumes that any string

4815 ** that this variable points to is held in memory obtained from

4816 ** [sqlite3_malloc] and the pragma may attempt to free that memory

4817 ** using [sqlite3_free].

4818 ** Hence, if this variable is modified directly, either it should be

4819 ** made NULL or made to point to memory obtained from [sqlite3_malloc]

4820 ** or else the use of the [data_store_directory pragma] should be avoided.

4821 */

4822 SQLITE_EXTERN char *sqlite3_data_directory;

4823

4824 /*

4825 ** CAPI3REF: Test For Auto-Commit Mode

4826 ** KEYWORDS: {autocommit mode}

4827 **

4828 ** ^The sqlite3_get_autocommit() interface returns non-zero or

4829 ** zero if the given database connection is or is not in autocommit mode,

4830 ** respectively. ^Autocommit mode is on by default.

4831 ** ^Autocommit mode is disabled by a [BEGIN] statement.

4832 ** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].

4833 **

4834 ** If certain kinds of errors occur on a statement within a multi-statement

4835 ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],

4836 ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the

4837 ** transaction might be rolled back automatically. The only way to

4838 ** find out whether SQLite automatically rolled back the transaction after

4839 ** an error is to use this function.

4840 **

4841 ** If another thread changes the autocommit status of the database

4842 ** connection while this routine is running, then the return value

4843 ** is undefined.

4844 */

4845 int sqlite3_get_autocommit(sqlite3*);

4846

4847 /*

4848 ** CAPI3REF: Find The Database Handle Of A Prepared Statement

4849 **

4850 ** ^The sqlite3_db_handle interface returns the [database connection] handle

4851 ** to which a [prepared statement] belongs. ^The [database connection]

4852 ** returned by sqlite3_db_handle is the same [database connection]

4853 ** that was the first argument

4854 ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to

4855 ** create the statement in the first place.

4856 */

4857 sqlite3 sqlite3_db_handle(sqlite3_stmt);

4858

4859 /*

4860 ** CAPI3REF: Return The Filename For A Database Connection

4861 **

4862 ** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename

4863 ** associated with database N of connection D. ^The main database file

4864 ** has the name "main". If there is no attached database N on the database

4865 ** connection D, or if database N is a temporary or in-memory database, then

4866 ** a NULL pointer is returned.

4867 **

4868 ** ^The filename returned by this function is the output of the

4869 ** xFullPathname method of the [VFS]. ^In other words, the filename

4870 ** will be an absolute pathname, even if the filename used

4871 ** to open the database originally was a URI or relative pathname.

4872 */

4873 const char sqlite3_db_filename(sqlite3 db, const char *zDbName);

4874

4875 /*

4876 ** CAPI3REF: Determine if a database is read-only

4877 **

4878 ** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N

4879 ** of connection D is read-only, 0 if it is read/write, or -1 if N is not

4880 ** the name of a database on connection D.

4881 */

4882 int sqlite3_db_readonly(sqlite3 db, const char zDbName);

4883

4884 /*

4885 ** CAPI3REF: Find the next prepared statement

4886 **

4887 ** ^This interface returns a pointer to the next [prepared statement] after

4888 ** pStmt associated with the [database connection] pDb. ^If pStmt is NULL

4889 ** then this interface returns a pointer to the first prepared statement

4890 ** associated with the database connection pDb. ^If no prepared statement

4891 ** satisfies the conditions of this routine, it returns NULL.

4892 **

4893 ** The [database connection] pointer D in a call to

4894 ** [sqlite3_next_stmt(D,S)] must refer to an open database

4895 ** connection and in particular must not be a NULL pointer.

4896 */

4897 sqlite3_stmt sqlite3_next_stmt(sqlite3 pDb, sqlite3_stmt *pStmt);

4898

4899 /*

4900 ** CAPI3REF: Commit And Rollback Notification Callbacks

4901 **

4902 ** ^The sqlite3_commit_hook() interface registers a callback

4903 ** function to be invoked whenever a transaction is [COMMIT \| committed].

4904 ** ^Any callback set by a previous call to sqlite3_commit_hook()

4905 ** for the same database connection is overridden.

4906 ** ^The sqlite3_rollback_hook() interface registers a callback

4907 ** function to be invoked whenever a transaction is [ROLLBACK \| rolled back].

4908 ** ^Any callback set by a previous call to sqlite3_rollback_hook()

4909 ** for the same database connection is overridden.

4910 ** ^The pArg argument is passed through to the callback.

4911 ** ^If the callback on a commit hook function returns non-zero,

4912 ** then the commit is converted into a rollback.

4913 **

4914 ** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions

4915 ** return the P argument from the previous call of the same function

4916 ** on the same [database connection] D, or NULL for

4917 ** the first call for each function on D.

4918 **

4919 ** The commit and rollback hook callbacks are not reentrant.

4920 ** The callback implementation must not do anything that will modify

4921 ** the database connection that invoked the callback. Any actions

4922 ** to modify the database connection must be deferred until after the

4923 ** completion of the [sqlite3_step()] call that triggered the commit

4924 ** or rollback hook in the first place.

4925 ** Note that running any other SQL statements, including SELECT statements,

4926 ** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify

4927 ** the database connections for the meaning of "modify" in this paragraph.

4928 **

4929 ** ^Registering a NULL function disables the callback.

4930 **

4931 ** ^When the commit hook callback routine returns zero, the [COMMIT]

4932 ** operation is allowed to continue normally. ^If the commit hook

4933 ** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].

4934 ** ^The rollback hook is invoked on a rollback that results from a commit

4935 ** hook returning non-zero, just as it would be with any other rollback.

4936 **

4937 ** ^For the purposes of this API, a transaction is said to have been

4938 ** rolled back if an explicit "ROLLBACK" statement is executed, or

4939 ** an error or constraint causes an implicit rollback to occur.

4940 ** ^The rollback callback is not invoked if a transaction is

4941 ** automatically rolled back because the database connection is closed.

4942 **

4943 ** See also the [sqlite3_update_hook()] interface.

4944 */

4945 void sqlite3_commit_hook(sqlite3, int()(void), void*);

4946 void sqlite3_rollback_hook(sqlite3, void()(void ), void*);

4947

4948 /*

4949 ** CAPI3REF: Data Change Notification Callbacks

4950 **

4951 ** ^The sqlite3_update_hook() interface registers a callback function

4952 ** with the [database connection] identified by the first argument

4953 ** to be invoked whenever a row is updated, inserted or deleted in

4954 ** a rowid table.

4955 ** ^Any callback set by a previous call to this function

4956 ** for the same database connection is overridden.

4957 **

4958 ** ^The second argument is a pointer to the function to invoke when a

4959 ** row is updated, inserted or deleted in a rowid table.

4960 ** ^The first argument to the callback is a copy of the third argument

4961 ** to sqlite3_update_hook().

4962 ** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],

4963 ** or [SQLITE_UPDATE], depending on the operation that caused the callback

4964 ** to be invoked.

4965 ** ^The third and fourth arguments to the callback contain pointers to the

4966 ** database and table name containing the affected row.

4967 ** ^The final callback parameter is the [rowid] of the row.

4968 ** ^In the case of an update, this is the [rowid] after the update takes place.

4969 **

4970 ** ^(The update hook is not invoked when internal system tables are

4971 ** modified (i.e. sqlite_master and sqlite_sequence).)^

4972 ** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified.

4973 **

4974 ** ^In the current implementation, the update hook

4975 ** is not invoked when duplication rows are deleted because of an

4976 ** [ON CONFLICT \| ON CONFLICT REPLACE] clause. ^Nor is the update hook

4977 ** invoked when rows are deleted using the [truncate optimization].

4978 ** The exceptions defined in this paragraph might change in a future

4979 ** release of SQLite.

4980 **

4981 ** The update hook implementation must not do anything that will modify

4982 ** the database connection that invoked the update hook. Any actions

4983 ** to modify the database connection must be deferred until after the

4984 ** completion of the [sqlite3_step()] call that triggered the update hook.

4985 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their

4986 ** database connections for the meaning of "modify" in this paragraph.

4987 **

4988 ** ^The sqlite3_update_hook(D,C,P) function

4989 ** returns the P argument from the previous call

4990 ** on the same [database connection] D, or NULL for

4991 ** the first call on D.

4992 **

4993 ** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()]

4994 ** interfaces.

4995 */

4996 void *sqlite3_update_hook(

4997 sqlite3*,

4998 void()(void ,int ,char const ,char const ,sqlite3_int64),

4999 void*

5000 );

5001

5002 /*

5003 ** CAPI3REF: Enable Or Disable Shared Pager Cache

5004 **

5005 ** ^(This routine enables or disables the sharing of the database cache

5006 ** and schema data structures between [database connection \| connections]

5007 ** to the same database. Sharing is enabled if the argument is true

5008 ** and disabled if the argument is false.)^

5009 **

5010 ** ^Cache sharing is enabled and disabled for an entire process.

5011 ** This is a change as of SQLite version 3.5.0. In prior versions of SQLite,

5012 ** sharing was enabled or disabled for each thread separately.

5013 **

5014 ** ^(The cache sharing mode set by this interface effects all subsequent

5015 ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].

5016 ** Existing database connections continue use the sharing mode

5017 ** that was in effect at the time they were opened.)^

5018 **

5019 ** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled

5020 ** successfully. An [error code] is returned otherwise.)^

5021 **

5022 ** ^Shared cache is disabled by default. But this might change in

5023 ** future releases of SQLite. Applications that care about shared

5024 ** cache setting should set it explicitly.

5025 **

5026 ** This interface is threadsafe on processors where writing a

5027 ** 32-bit integer is atomic.

5028 **

5029 ** See Also: [SQLite Shared-Cache Mode]

5030 */

5031 int sqlite3_enable_shared_cache(int);

5032

5033 /*

5034 ** CAPI3REF: Attempt To Free Heap Memory

5035 **

5036 ** ^The sqlite3_release_memory() interface attempts to free N bytes

5037 ** of heap memory by deallocating non-essential memory allocations

5038 ** held by the database library. Memory used to cache database

5039 ** pages to improve performance is an example of non-essential memory.

5040 ** ^sqlite3_release_memory() returns the number of bytes actually freed,

5041 ** which might be more or less than the amount requested.

5042 ** ^The sqlite3_release_memory() routine is a no-op returning zero

5043 ** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].

5044 **

5045 ** See also: [sqlite3_db_release_memory()]

5046 */

5047 int sqlite3_release_memory(int);

5048

5049 /*

5050 ** CAPI3REF: Free Memory Used By A Database Connection

5051 **

5052 ** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap

5053 ** memory as possible from database connection D. Unlike the

5054 ** [sqlite3_release_memory()] interface, this interface is in effect even

5055 ** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is

5056 ** omitted.

5057 **

5058 ** See also: [sqlite3_release_memory()]

5059 */

5060 int sqlite3_db_release_memory(sqlite3*);

5061

5062 /*

5063 ** CAPI3REF: Impose A Limit On Heap Size

5064 **

5065 ** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the

5066 ** soft limit on the amount of heap memory that may be allocated by SQLite.

5067 ** ^SQLite strives to keep heap memory utilization below the soft heap

5068 ** limit by reducing the number of pages held in the page cache

5069 ** as heap memory usages approaches the limit.

5070 ** ^The soft heap limit is "soft" because even though SQLite strives to stay

5071 ** below the limit, it will exceed the limit rather than generate

5072 ** an [SQLITE_NOMEM] error. In other words, the soft heap limit

5073 ** is advisory only.

5074 **

5075 ** ^The return value from sqlite3_soft_heap_limit64() is the size of

5076 ** the soft heap limit prior to the call, or negative in the case of an

5077 ** error. ^If the argument N is negative

5078 ** then no change is made to the soft heap limit. Hence, the current

5079 ** size of the soft heap limit can be determined by invoking

5080 ** sqlite3_soft_heap_limit64() with a negative argument.

5081 **

5082 ** ^If the argument N is zero then the soft heap limit is disabled.

5083 **

5084 ** ^(The soft heap limit is not enforced in the current implementation

5085 ** if one or more of following conditions are true:

5086 **

5087 ** <ul>

5088 ** <li> The soft heap limit is set to zero.

5089 ** <li> Memory accounting is disabled using a combination of the

5090 ** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and

5091 ** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.

5092 ** <li> An alternative page cache implementation is specified using

5093 ** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).

5094 ** <li> The page cache allocates from its own memory pool supplied

5095 ** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than

5096 ** from the heap.

5097 ** </ul>)^

5098 **

5099 ** Beginning with SQLite version 3.7.3, the soft heap limit is enforced

5100 ** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT]

5101 ** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT],

5102 ** the soft heap limit is enforced on every memory allocation. Without

5103 ** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced

5104 ** when memory is allocated by the page cache. Testing suggests that because

5105 ** the page cache is the predominate memory user in SQLite, most

5106 ** applications will achieve adequate soft heap limit enforcement without

5107 ** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT].

5108 **

5109 ** The circumstances under which SQLite will enforce the soft heap limit may

5110 ** changes in future releases of SQLite.

5111 */

5112 sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);

5113

5114 /*

5115 ** CAPI3REF: Deprecated Soft Heap Limit Interface

5116 ** DEPRECATED

5117 **

5118 ** This is a deprecated version of the [sqlite3_soft_heap_limit64()]

5119 ** interface. This routine is provided for historical compatibility

5120 ** only. All new applications should use the

5121 ** [sqlite3_soft_heap_limit64()] interface rather than this one.

5122 */

5123 SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N);

5124

5125

5126 /*

5127 ** CAPI3REF: Extract Metadata About A Column Of A Table

5128 **

5129 ** ^This routine returns metadata about a specific column of a specific

5130 ** database table accessible using the [database connection] handle

5131 ** passed as the first function argument.

5132 **

5133 ** ^The column is identified by the second, third and fourth parameters to

5134 ** this function. ^The second parameter is either the name of the database

5135 ** (i.e. "main", "temp", or an attached database) containing the specified

5136 ** table or NULL. ^If it is NULL, then all attached databases are searched

5137 ** for the table using the same algorithm used by the database engine to

5138 ** resolve unqualified table references.

5139 **

5140 ** ^The third and fourth parameters to this function are the table and column

5141 ** name of the desired column, respectively. Neither of these parameters

5142 ** may be NULL.

5143 **

5144 ** ^Metadata is returned by writing to the memory locations passed as the 5th

5145 ** and subsequent parameters to this function. ^Any of these arguments may be

5146 ** NULL, in which case the corresponding element of metadata is omitted.

5147 **

5148 ** ^(<blockquote>

5149 ** <table border="1">

5150 ** <tr><th> Parameter <th> Output<br>Type <th> Description

5151 **

5152 ** <tr><td> 5th <td> const char* <td> Data type

5153 ** <tr><td> 6th <td> const char* <td> Name of default collation sequence

5154 ** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint

5155 ** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY

5156 ** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT]

5157 ** </table>

5158 ** </blockquote>)^

5159 **

5160 ** ^The memory pointed to by the character pointers returned for the

5161 ** declaration type and collation sequence is valid only until the next

5162 ** call to any SQLite API function.

5163 **

5164 ** ^If the specified table is actually a view, an [error code] is returned.

5165 **

5166 ** ^If the specified column is "rowid", "oid" or "_rowid_" and an

5167 ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output

5168 ** parameters are set for the explicitly declared column. ^(If there is no

5169 ** explicitly declared [INTEGER PRIMARY KEY] column, then the output

5170 ** parameters are set as follows:

5171 **

5172 ** <pre>

5173 ** data type: "INTEGER"

5174 ** collation sequence: "BINARY"

5175 ** not null: 0

5176 ** primary key: 1

5177 ** auto increment: 0

5178 ** </pre>)^

5179 **

5180 ** ^(This function may load one or more schemas from database files. If an

5181 ** error occurs during this process, or if the requested table or column

5182 ** cannot be found, an [error code] is returned and an error message left

5183 ** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^

5184 **

5185 ** ^This API is only available if the library was compiled with the

5186 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined.

5187 */

5188 int sqlite3_table_column_metadata(

5189 sqlite3 db, / Connection handle */

5190 const char zDbName, / Database name or NULL */

5191 const char zTableName, / Table name */

5192 const char zColumnName, / Column name */

5193 char const *pzDataType, / OUTPUT: Declared data type */

5194 char const *pzCollSeq, / OUTPUT: Collation sequence name */

5195 int pNotNull, / OUTPUT: True if NOT NULL constraint exists */

5196 int pPrimaryKey, / OUTPUT: True if column part of PK */

5197 int pAutoinc / OUTPUT: True if column is auto-increment */

5198 );

5199

5200 /*

5201 ** CAPI3REF: Load An Extension

5202 **

5203 ** ^This interface loads an SQLite extension library from the named file.

5204 **

5205 ** ^The sqlite3_load_extension() interface attempts to load an

5206 ** [SQLite extension] library contained in the file zFile. If

5207 ** the file cannot be loaded directly, attempts are made to load

5208 ** with various operating-system specific extensions added.

5209 ** So for example, if "samplelib" cannot be loaded, then names like

5210 ** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might

5211 ** be tried also.

5212 **

5213 ** ^The entry point is zProc.

5214 ** ^(zProc may be 0, in which case SQLite will try to come up with an

5215 ** entry point name on its own. It first tries "sqlite3_extension_init".

5216 ** If that does not work, it constructs a name "sqlite3_X_init" where the

5217 ** X is consists of the lower-case equivalent of all ASCII alphabetic

5218 ** characters in the filename from the last "/" to the first following

5219 ** "." and omitting any initial "lib".)^

5220 ** ^The sqlite3_load_extension() interface returns

5221 ** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.

5222 ** ^If an error occurs and pzErrMsg is not 0, then the

5223 ** [sqlite3_load_extension()] interface shall attempt to

5224 ** fill *pzErrMsg with error message text stored in memory

5225 ** obtained from [sqlite3_malloc()]. The calling function

5226 ** should free this memory by calling [sqlite3_free()].

5227 **

5228 ** ^Extension loading must be enabled using

5229 ** [sqlite3_enable_load_extension()] prior to calling this API,

5230 ** otherwise an error will be returned.

5231 **

5232 ** See also the [load_extension() SQL function].

5233 */

5234 int sqlite3_load_extension(

5235 sqlite3 db, / Load the extension into this database connection */

5236 const char zFile, / Name of the shared library containing extension */

5237 const char zProc, / Entry point. Derived from zFile if 0 */

5238 char *pzErrMsg / Put error message here if not 0 */

5239 );

5240

5241 /*

5242 ** CAPI3REF: Enable Or Disable Extension Loading

5243 **

5244 ** ^So as not to open security holes in older applications that are

5245 ** unprepared to deal with [extension loading], and as a means of disabling

5246 ** [extension loading] while evaluating user-entered SQL, the following API

5247 ** is provided to turn the [sqlite3_load_extension()] mechanism on and off.

5248 **

5249 ** ^Extension loading is off by default.

5250 ** ^Call the sqlite3_enable_load_extension() routine with onoff==1

5251 ** to turn extension loading on and call it with onoff==0 to turn

5252 ** it back off again.

5253 */

5254 int sqlite3_enable_load_extension(sqlite3 *db, int onoff);

5255

5256 /*

5257 ** CAPI3REF: Automatically Load Statically Linked Extensions

5258 **

5259 ** ^This interface causes the xEntryPoint() function to be invoked for

5260 ** each new [database connection] that is created. The idea here is that

5261 ** xEntryPoint() is the entry point for a statically linked [SQLite extension]

5262 ** that is to be automatically loaded into all new database connections.

5263 **

5264 ** ^(Even though the function prototype shows that xEntryPoint() takes

5265 ** no arguments and returns void, SQLite invokes xEntryPoint() with three

5266 ** arguments and expects and integer result as if the signature of the

5267 ** entry point where as follows:

5268 **

5269 ** <blockquote><pre>

5270 **   int xEntryPoint(

5271 **   sqlite3 *db,

5272   const char pzErrMsg,

5273 **   const struct sqlite3_api_routines *pThunk

5274 **   );

5275 ** </pre></blockquote>)^

5276 **

5277 ** If the xEntryPoint routine encounters an error, it should make *pzErrMsg

5278 ** point to an appropriate error message (obtained from [sqlite3_mprintf()])

5279 ** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg

5280 ** is NULL before calling the xEntryPoint(). ^SQLite will invoke

5281 ** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any

5282 ** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],

5283 ** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.

5284 **

5285 ** ^Calling sqlite3_auto_extension(X) with an entry point X that is already

5286 ** on the list of automatic extensions is a harmless no-op. ^No entry point

5287 ** will be called more than once for each database connection that is opened.

5288 **

5289 ** See also: [sqlite3_reset_auto_extension()]

5290 ** and [sqlite3_cancel_auto_extension()]

5291 */

5292 int sqlite3_auto_extension(void (*xEntryPoint)(void));

5293

5294 /*

5295 ** CAPI3REF: Cancel Automatic Extension Loading

5296 **

5297 ** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the

5298 ** initialization routine X that was registered using a prior call to

5299 ** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)]

5300 ** routine returns 1 if initialization routine X was successfully

5301 ** unregistered and it returns 0 if X was not on the list of initialization

5302 ** routines.

5303 */

5304 int sqlite3_cancel_auto_extension(void (*xEntryPoint)(void));

5305

5306 /*

5307 ** CAPI3REF: Reset Automatic Extension Loading

5308 **

5309 ** ^This interface disables all automatic extensions previously

5310 ** registered using [sqlite3_auto_extension()].

5311 */

5312 void sqlite3_reset_auto_extension(void);

5313

5314 /*

5315 ** The interface to the virtual-table mechanism is currently considered

5316 ** to be experimental. The interface might change in incompatible ways.

5317 ** If this is a problem for you, do not use the interface at this time.

5318 **

5319 ** When the virtual-table mechanism stabilizes, we will declare the

5320 ** interface fixed, support it indefinitely, and remove this comment.

5321 */

5322

5323 /*

5324 ** Structures used by the virtual table interface

5325 */

5326 typedef struct sqlite3_vtab sqlite3_vtab;

5327 typedef struct sqlite3_index_info sqlite3_index_info;

5328 typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;

5329 typedef struct sqlite3_module sqlite3_module;

5330

5331 /*

5332 ** CAPI3REF: Virtual Table Object

5333 ** KEYWORDS: sqlite3_module {virtual table module}

5334 **

5335 ** This structure, sometimes called a "virtual table module",

5336 ** defines the implementation of a [virtual tables].

5337 ** This structure consists mostly of methods for the module.

5338 **

5339 ** ^A virtual table module is created by filling in a persistent

5340 ** instance of this structure and passing a pointer to that instance

5341 ** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].

5342 ** ^The registration remains valid until it is replaced by a different

5343 ** module or until the [database connection] closes. The content

5344 ** of this structure must not change while it is registered with

5345 ** any database connection.

5346 */

5347 struct sqlite3_module {

5348 int iVersion;

5349 int (xCreate)(sqlite3, void *pAux,

5350 int argc, const char constargv,

5351 sqlite3_vtab ppVTab, char);

5352 int (xConnect)(sqlite3, void *pAux,

5353 int argc, const char constargv,

5354 sqlite3_vtab ppVTab, char);

5355 int (xBestIndex)(sqlite3_vtab pVTab, sqlite3_index_info*);

5356 int (xDisconnect)(sqlite3_vtab pVTab);

5357 int (xDestroy)(sqlite3_vtab pVTab);

5358 int (xOpen)(sqlite3_vtab pVTab, sqlite3_vtab_cursor **ppCursor);

5359 int (xClose)(sqlite3_vtab_cursor);

5360 int (xFilter)(sqlite3_vtab_cursor, int idxNum, const char *idxStr,

5361 int argc, sqlite3_value **argv);

5362 int (xNext)(sqlite3_vtab_cursor);

5363 int (xEof)(sqlite3_vtab_cursor);

5364 int (xColumn)(sqlite3_vtab_cursor, sqlite3_context*, int);

5365 int (xRowid)(sqlite3_vtab_cursor, sqlite3_int64 *pRowid);

5366 int (xUpdate)(sqlite3_vtab , int, sqlite3_value *, sqlite3_int64 );

5367 int (xBegin)(sqlite3_vtab pVTab);

5368 int (xSync)(sqlite3_vtab pVTab);

5369 int (xCommit)(sqlite3_vtab pVTab);

5370 int (xRollback)(sqlite3_vtab pVTab);

5371 int (xFindFunction)(sqlite3_vtab pVtab, int nArg, const char *zName,

5372 void (*pxFunc)(sqlite3_context,int,sqlite3_value**),

5373 void **ppArg);

5374 int (xRename)(sqlite3_vtab pVtab, const char *zNew);

5375 /* The methods above are in version 1 of the sqlite_module object. Those

5376 ** below are for version 2 and greater. */

5377 int (xSavepoint)(sqlite3_vtab pVTab, int);

5378 int (xRelease)(sqlite3_vtab pVTab, int);

5379 int (xRollbackTo)(sqlite3_vtab pVTab, int);

5380 };

5381

5382 /*

5383 ** CAPI3REF: Virtual Table Indexing Information

5384 ** KEYWORDS: sqlite3_index_info

5385 **

5386 ** The sqlite3_index_info structure and its substructures is used as part

5387 ** of the [virtual table] interface to

5388 ** pass information into and receive the reply from the [xBestIndex]

5389 method of a [virtual table module]. The fields under Inputs** are the

5390 ** inputs to xBestIndex and are read-only. xBestIndex inserts its

5391 results into the Outputs** fields.

5392 **

5393 ** ^(The aConstraint[] array records WHERE clause constraints of the form:

5394 **

5395 ** <blockquote>column OP expr</blockquote>

5396 **

5397 ** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is

5398 ** stored in aConstraint[].op using one of the

5399 ** [SQLITE_INDEX_CONSTRAINT_EQ \| SQLITE_INDEX_CONSTRAINT_ values].)^

5400 ** ^(The index of the column is stored in

5401 ** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the

5402 ** expr on the right-hand side can be evaluated (and thus the constraint

5403 ** is usable) and false if it cannot.)^

5404 **

5405 ** ^The optimizer automatically inverts terms of the form "expr OP column"

5406 ** and makes other simplifications to the WHERE clause in an attempt to

5407 ** get as many WHERE clause terms into the form shown above as possible.

5408 ** ^The aConstraint[] array only reports WHERE clause terms that are

5409 ** relevant to the particular virtual table being queried.

5410 **

5411 ** ^Information about the ORDER BY clause is stored in aOrderBy[].

5412 ** ^Each term of aOrderBy records a column of the ORDER BY clause.

5413 **

5414 ** The [xBestIndex] method must fill aConstraintUsage[] with information

5415 ** about what parameters to pass to xFilter. ^If argvIndex>0 then

5416 ** the right-hand side of the corresponding aConstraint[] is evaluated

5417 ** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit

5418 ** is true, then the constraint is assumed to be fully handled by the

5419 ** virtual table and is not checked again by SQLite.)^

5420 **

5421 ** ^The idxNum and idxPtr values are recorded and passed into the

5422 ** [xFilter] method.

5423 ** ^[sqlite3_free()] is used to free idxPtr if and only if

5424 ** needToFreeIdxPtr is true.

5425 **

5426 ** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in

5427 ** the correct order to satisfy the ORDER BY clause so that no separate

5428 ** sorting step is required.

5429 **

5430 ** ^The estimatedCost value is an estimate of the cost of a particular

5431 ** strategy. A cost of N indicates that the cost of the strategy is similar

5432 ** to a linear scan of an SQLite table with N rows. A cost of log(N)

5433 ** indicates that the expense of the operation is similar to that of a

5434 ** binary search on a unique indexed field of an SQLite table with N rows.

5435 **

5436 ** ^The estimatedRows value is an estimate of the number of rows that

5437 ** will be returned by the strategy.

5438 **

5439 ** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info

5440 ** structure for SQLite version 3.8.2. If a virtual table extension is

5441 ** used with an SQLite version earlier than 3.8.2, the results of attempting

5442 ** to read or write the estimatedRows field are undefined (but are likely

5443 ** to included crashing the application). The estimatedRows field should

5444 ** therefore only be used if [sqlite3_libversion_number()] returns a

5445 ** value greater than or equal to 3008002.

5446 */

5447 struct sqlite3_index_info {

5448 /* Inputs */

5449 int nConstraint; /* Number of entries in aConstraint */

5450 struct sqlite3_index_constraint {

5451 int iColumn; /* Column on left-hand side of constraint */

5452 unsigned char op; /* Constraint operator */

5453 unsigned char usable; /* True if this constraint is usable */

5454 int iTermOffset; /* Used internally - xBestIndex should ignore */

5455 } aConstraint; / Table of WHERE clause constraints */

5456 int nOrderBy; /* Number of terms in the ORDER BY clause */

5457 struct sqlite3_index_orderby {

5458 int iColumn; /* Column number */

5459 unsigned char desc; /* True for DESC. False for ASC. */

5460 } aOrderBy; / The ORDER BY clause */

5461 /* Outputs */

5462 struct sqlite3_index_constraint_usage {

5463 int argvIndex; /* if >0, constraint is part of argv to xFilter */

5464 unsigned char omit; /* Do not code a test for this constraint */

5465 } *aConstraintUsage;

5466 int idxNum; /* Number used to identify the index */

5467 char idxStr; / String, possibly obtained from sqlite3_malloc */

5468 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */

5469 int orderByConsumed; /* True if output is already ordered */

5470 double estimatedCost; /* Estimated cost of using this index */

5471 /* Fields below are only available in SQLite 3.8.2 and later */

5472 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */

5473 };

5474

5475 /*

5476 ** CAPI3REF: Virtual Table Constraint Operator Codes

5477 **

5478 ** These macros defined the allowed values for the

5479 ** [sqlite3_index_info].aConstraint[].op field. Each value represents

5480 ** an operator that is part of a constraint term in the wHERE clause of

5481 ** a query that uses a [virtual table].

5482 */

5483 #define SQLITE_INDEX_CONSTRAINT_EQ 2

5484 #define SQLITE_INDEX_CONSTRAINT_GT 4

5485 #define SQLITE_INDEX_CONSTRAINT_LE 8

5486 #define SQLITE_INDEX_CONSTRAINT_LT 16

5487 #define SQLITE_INDEX_CONSTRAINT_GE 32

5488 #define SQLITE_INDEX_CONSTRAINT_MATCH 64

5489

5490 /*

5491 ** CAPI3REF: Register A Virtual Table Implementation

5492 **

5493 ** ^These routines are used to register a new [virtual table module] name.

5494 ** ^Module names must be registered before

5495 ** creating a new [virtual table] using the module and before using a

5496 ** preexisting [virtual table] for the module.

5497 **

5498 ** ^The module name is registered on the [database connection] specified

5499 ** by the first parameter. ^The name of the module is given by the

5500 ** second parameter. ^The third parameter is a pointer to

5501 ** the implementation of the [virtual table module]. ^The fourth

5502 ** parameter is an arbitrary client data pointer that is passed through

5503 ** into the [xCreate] and [xConnect] methods of the virtual table module

5504 ** when a new virtual table is be being created or reinitialized.

5505 **

5506 ** ^The sqlite3_create_module_v2() interface has a fifth parameter which

5507 ** is a pointer to a destructor for the pClientData. ^SQLite will

5508 ** invoke the destructor function (if it is not NULL) when SQLite

5509 ** no longer needs the pClientData pointer. ^The destructor will also

5510 ** be invoked if the call to sqlite3_create_module_v2() fails.

5511 ** ^The sqlite3_create_module()

5512 ** interface is equivalent to sqlite3_create_module_v2() with a NULL

5513 ** destructor.

5514 */

5515 int sqlite3_create_module(

5516 sqlite3 db, / SQLite connection to register module with */

5517 const char zName, / Name of the module */

5518 const sqlite3_module p, / Methods for the module */

5519 void pClientData / Client data for xCreate/xConnect */

5520 );

5521 int sqlite3_create_module_v2(

5522 sqlite3 db, / SQLite connection to register module with */

5523 const char zName, / Name of the module */

5524 const sqlite3_module p, / Methods for the module */

5525 void pClientData, / Client data for xCreate/xConnect */

5526 void(xDestroy)(void) /* Module destructor function */

5527 );

5528

5529 /*

5530 ** CAPI3REF: Virtual Table Instance Object

5531 ** KEYWORDS: sqlite3_vtab

5532 **

5533 ** Every [virtual table module] implementation uses a subclass

5534 ** of this object to describe a particular instance

5535 ** of the [virtual table]. Each subclass will

5536 ** be tailored to the specific needs of the module implementation.

5537 ** The purpose of this superclass is to define certain fields that are

5538 ** common to all module implementations.

5539 **

5540 ** ^Virtual tables methods can set an error message by assigning a

5541 ** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should

5542 ** take care that any prior string is freed by a call to [sqlite3_free()]

5543 ** prior to assigning a new string to zErrMsg. ^After the error message

5544 ** is delivered up to the client application, the string will be automatically

5545 ** freed by sqlite3_free() and the zErrMsg field will be zeroed.

5546 */

5547 struct sqlite3_vtab {

5548 const sqlite3_module pModule; / The module for this virtual table */

5549 int nRef; /* NO LONGER USED */

5550 char zErrMsg; / Error message from sqlite3_mprintf() */

5551 /* Virtual table implementations will typically add additional fields */

5552 };

5553

5554 /*

5555 ** CAPI3REF: Virtual Table Cursor Object

5556 ** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}

5557 **

5558 ** Every [virtual table module] implementation uses a subclass of the

5559 ** following structure to describe cursors that point into the

5560 ** [virtual table] and are used

5561 ** to loop through the virtual table. Cursors are created using the

5562 ** [sqlite3_module.xOpen \| xOpen] method of the module and are destroyed

5563 ** by the [sqlite3_module.xClose \| xClose] method. Cursors are used

5564 ** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods

5565 ** of the module. Each module implementation will define

5566 ** the content of a cursor structure to suit its own needs.

5567 **

5568 ** This superclass exists in order to define fields of the cursor that

5569 ** are common to all implementations.

5570 */

5571 struct sqlite3_vtab_cursor {

5572 sqlite3_vtab pVtab; / Virtual table of this cursor */

5573 /* Virtual table implementations will typically add additional fields */

5574 };

5575

5576 /*

5577 ** CAPI3REF: Declare The Schema Of A Virtual Table

5578 **

5579 ** ^The [xCreate] and [xConnect] methods of a

5580 ** [virtual table module] call this interface

5581 ** to declare the format (the names and datatypes of the columns) of

5582 ** the virtual tables they implement.

5583 */

5584 int sqlite3_declare_vtab(sqlite3, const char zSQL);

5585

5586 /*

5587 ** CAPI3REF: Overload A Function For A Virtual Table

5588 **

5589 ** ^(Virtual tables can provide alternative implementations of functions

5590 ** using the [xFindFunction] method of the [virtual table module].

5591 ** But global versions of those functions

5592 ** must exist in order to be overloaded.)^

5593 **

5594 ** ^(This API makes sure a global version of a function with a particular

5595 ** name and number of parameters exists. If no such function exists

5596 ** before this API is called, a new function is created.)^ ^The implementation

5597 ** of the new function always causes an exception to be thrown. So

5598 ** the new function is not good for anything by itself. Its only

5599 ** purpose is to be a placeholder function that can be overloaded

5600 ** by a [virtual table].

5601 */

5602 int sqlite3_overload_function(sqlite3, const char zFuncName, int nArg);

5603

5604 /*

5605 ** The interface to the virtual-table mechanism defined above (back up

5606 ** to a comment remarkably similar to this one) is currently considered

5607 ** to be experimental. The interface might change in incompatible ways.

5608 ** If this is a problem for you, do not use the interface at this time.

5609 **

5610 ** When the virtual-table mechanism stabilizes, we will declare the

5611 ** interface fixed, support it indefinitely, and remove this comment.

5612 */

5613

5614 /*

5615 ** CAPI3REF: A Handle To An Open BLOB

5616 ** KEYWORDS: {BLOB handle} {BLOB handles}

5617 **

5618 ** An instance of this object represents an open BLOB on which

5619 ** [sqlite3_blob_open \| incremental BLOB I/O] can be performed.

5620 ** ^Objects of this type are created by [sqlite3_blob_open()]

5621 ** and destroyed by [sqlite3_blob_close()].

5622 ** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces

5623 ** can be used to read or write small subsections of the BLOB.

5624 ** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.

5625 */

5626 typedef struct sqlite3_blob sqlite3_blob;

5627

5628 /*

5629 ** CAPI3REF: Open A BLOB For Incremental I/O

5630 **

5631 ** ^(This interfaces opens a [BLOB handle \| handle] to the BLOB located

5632 ** in row iRow, column zColumn, table zTable in database zDb;

5633 ** in other words, the same BLOB that would be selected by:

5634 **

5635 ** <pre>

5636 ** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;

5637 ** </pre>)^

5638 **

5639 ** ^If the flags parameter is non-zero, then the BLOB is opened for read

5640 ** and write access. ^If it is zero, the BLOB is opened for read access.

5641 ** ^It is not possible to open a column that is part of an index or primary

5642 ** key for writing. ^If [foreign key constraints] are enabled, it is

5643 ** not possible to open a column that is part of a [child key] for writing.

5644 **

5645 ** ^Note that the database name is not the filename that contains

5646 ** the database but rather the symbolic name of the database that

5647 ** appears after the AS keyword when the database is connected using [ATTACH].

5648 ** ^For the main database file, the database name is "main".

5649 ** ^For TEMP tables, the database name is "temp".

5650 **

5651 ** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written

5652 ** to ppBlob. Otherwise an [error code] is returned and ppBlob is set

5653 ** to be a null pointer.)^

5654 ** ^This function sets the [database connection] error code and message

5655 ** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related

5656 ** functions. ^Note that the *ppBlob variable is always initialized in a

5657 ** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob

5658 ** regardless of the success or failure of this routine.

5659 **

5660 ** ^(If the row that a BLOB handle points to is modified by an

5661 ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects

5662 ** then the BLOB handle is marked as "expired".

5663 ** This is true if any column of the row is changed, even a column

5664 ** other than the one the BLOB handle is open on.)^

5665 ** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for

5666 ** an expired BLOB handle fail with a return code of [SQLITE_ABORT].

5667 ** ^(Changes written into a BLOB prior to the BLOB expiring are not

5668 ** rolled back by the expiration of the BLOB. Such changes will eventually

5669 ** commit if the transaction continues to completion.)^

5670 **

5671 ** ^Use the [sqlite3_blob_bytes()] interface to determine the size of

5672 ** the opened blob. ^The size of a blob may not be changed by this

5673 ** interface. Use the [UPDATE] SQL command to change the size of a

5674 ** blob.

5675 **

5676 ** ^The [sqlite3_blob_open()] interface will fail for a [WITHOUT ROWID]

5677 ** table. Incremental BLOB I/O is not possible on [WITHOUT ROWID] tables.

5678 **

5679 ** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces

5680 ** and the built-in [zeroblob] SQL function can be used, if desired,

5681 ** to create an empty, zero-filled blob in which to read or write using

5682 ** this interface.

5683 **

5684 ** To avoid a resource leak, every open [BLOB handle] should eventually

5685 ** be released by a call to [sqlite3_blob_close()].

5686 */

5687 int sqlite3_blob_open(

5688 sqlite3*,

5689 const char *zDb,

5690 const char *zTable,

5691 const char *zColumn,

5692 sqlite3_int64 iRow,

5693 int flags,

5694 sqlite3_blob **ppBlob

5695 );

5696

5697 /*

5698 ** CAPI3REF: Move a BLOB Handle to a New Row

5699 **

5700 ** ^This function is used to move an existing blob handle so that it points

5701 ** to a different row of the same database table. ^The new row is identified

5702 ** by the rowid value passed as the second argument. Only the row can be

5703 ** changed. ^The database, table and column on which the blob handle is open

5704 ** remain the same. Moving an existing blob handle to a new row can be

5705 ** faster than closing the existing handle and opening a new one.

5706 **

5707 ** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -

5708 ** it must exist and there must be either a blob or text value stored in

5709 ** the nominated column.)^ ^If the new row is not present in the table, or if

5710 ** it does not contain a blob or text value, or if another error occurs, an

5711 ** SQLite error code is returned and the blob handle is considered aborted.

5712 ** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or

5713 ** [sqlite3_blob_reopen()] on an aborted blob handle immediately return

5714 ** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle

5715 ** always returns zero.

5716 **

5717 ** ^This function sets the database handle error code and message.

5718 */

5719 SQLITE_EXPERIMENTAL int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);

5720

5721 /*

5722 ** CAPI3REF: Close A BLOB Handle

5723 **

5724 ** ^Closes an open [BLOB handle].

5725 **

5726 ** ^Closing a BLOB shall cause the current transaction to commit

5727 ** if there are no other BLOBs, no pending prepared statements, and the

5728 ** database connection is in [autocommit mode].

5729 ** ^If any writes were made to the BLOB, they might be held in cache

5730 ** until the close operation if they will fit.

5731 **

5732 ** ^(Closing the BLOB often forces the changes

5733 ** out to disk and so if any I/O errors occur, they will likely occur

5734 ** at the time when the BLOB is closed. Any errors that occur during

5735 ** closing are reported as a non-zero return value.)^

5736 **

5737 ** ^(The BLOB is closed unconditionally. Even if this routine returns

5738 ** an error code, the BLOB is still closed.)^

5739 **

5740 ** ^Calling this routine with a null pointer (such as would be returned

5741 ** by a failed call to [sqlite3_blob_open()]) is a harmless no-op.

5742 */

5743 int sqlite3_blob_close(sqlite3_blob *);

5744

5745 /*

5746 ** CAPI3REF: Return The Size Of An Open BLOB

5747 **

5748 ** ^Returns the size in bytes of the BLOB accessible via the

5749 ** successfully opened [BLOB handle] in its only argument. ^The

5750 ** incremental blob I/O routines can only read or overwriting existing

5751 ** blob content; they cannot change the size of a blob.

5752 **

5753 ** This routine only works on a [BLOB handle] which has been created

5754 ** by a prior successful call to [sqlite3_blob_open()] and which has not

5755 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in

5756 ** to this routine results in undefined and probably undesirable behavior.

5757 */

5758 int sqlite3_blob_bytes(sqlite3_blob *);

5759

5760 /*

5761 ** CAPI3REF: Read Data From A BLOB Incrementally

5762 **

5763 ** ^(This function is used to read data from an open [BLOB handle] into a

5764 ** caller-supplied buffer. N bytes of data are copied into buffer Z

5765 ** from the open BLOB, starting at offset iOffset.)^

5766 **

5767 ** ^If offset iOffset is less than N bytes from the end of the BLOB,

5768 ** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is

5769 ** less than zero, [SQLITE_ERROR] is returned and no data is read.

5770 ** ^The size of the blob (and hence the maximum value of N+iOffset)

5771 ** can be determined using the [sqlite3_blob_bytes()] interface.

5772 **

5773 ** ^An attempt to read from an expired [BLOB handle] fails with an

5774 ** error code of [SQLITE_ABORT].

5775 **

5776 ** ^(On success, sqlite3_blob_read() returns SQLITE_OK.

5777 ** Otherwise, an [error code] or an [extended error code] is returned.)^

5778 **

5779 ** This routine only works on a [BLOB handle] which has been created

5780 ** by a prior successful call to [sqlite3_blob_open()] and which has not

5781 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in

5782 ** to this routine results in undefined and probably undesirable behavior.

5783 **

5784 ** See also: [sqlite3_blob_write()].

5785 */

5786 int sqlite3_blob_read(sqlite3_blob , void Z, int N, int iOffset);

5787

5788 /*

5789 ** CAPI3REF: Write Data Into A BLOB Incrementally

5790 **

5791 ** ^This function is used to write data into an open [BLOB handle] from a

5792 ** caller-supplied buffer. ^N bytes of data are copied from the buffer Z

5793 ** into the open BLOB, starting at offset iOffset.

5794 **

5795 ** ^If the [BLOB handle] passed as the first argument was not opened for

5796 ** writing (the flags parameter to [sqlite3_blob_open()] was zero),

5797 ** this function returns [SQLITE_READONLY].

5798 **

5799 ** ^This function may only modify the contents of the BLOB; it is

5800 ** not possible to increase the size of a BLOB using this API.

5801 ** ^If offset iOffset is less than N bytes from the end of the BLOB,

5802 ** [SQLITE_ERROR] is returned and no data is written. ^If N is

5803 ** less than zero [SQLITE_ERROR] is returned and no data is written.

5804 ** The size of the BLOB (and hence the maximum value of N+iOffset)

5805 ** can be determined using the [sqlite3_blob_bytes()] interface.

5806 **

5807 ** ^An attempt to write to an expired [BLOB handle] fails with an

5808 ** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred

5809 ** before the [BLOB handle] expired are not rolled back by the

5810 ** expiration of the handle, though of course those changes might

5811 ** have been overwritten by the statement that expired the BLOB handle

5812 ** or by other independent statements.

5813 **

5814 ** ^(On success, sqlite3_blob_write() returns SQLITE_OK.

5815 ** Otherwise, an [error code] or an [extended error code] is returned.)^

5816 **

5817 ** This routine only works on a [BLOB handle] which has been created

5818 ** by a prior successful call to [sqlite3_blob_open()] and which has not

5819 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in

5820 ** to this routine results in undefined and probably undesirable behavior.

5821 **

5822 ** See also: [sqlite3_blob_read()].

5823 */

5824 int sqlite3_blob_write(sqlite3_blob , const void z, int n, int iOffset);

5825

5826 /*

5827 ** CAPI3REF: Virtual File System Objects

5828 **

5829 ** A virtual filesystem (VFS) is an [sqlite3_vfs] object

5830 ** that SQLite uses to interact

5831 ** with the underlying operating system. Most SQLite builds come with a

5832 ** single default VFS that is appropriate for the host computer.

5833 ** New VFSes can be registered and existing VFSes can be unregistered.

5834 ** The following interfaces are provided.

5835 **

5836 ** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.

5837 ** ^Names are case sensitive.

5838 ** ^Names are zero-terminated UTF-8 strings.

5839 ** ^If there is no match, a NULL pointer is returned.

5840 ** ^If zVfsName is NULL then the default VFS is returned.

5841 **

5842 ** ^New VFSes are registered with sqlite3_vfs_register().

5843 ** ^Each new VFS becomes the default VFS if the makeDflt flag is set.

5844 ** ^The same VFS can be registered multiple times without injury.

5845 ** ^To make an existing VFS into the default VFS, register it again

5846 ** with the makeDflt flag set. If two different VFSes with the

5847 ** same name are registered, the behavior is undefined. If a

5848 ** VFS is registered with a name that is NULL or an empty string,

5849 ** then the behavior is undefined.

5850 **

5851 ** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.

5852 ** ^(If the default VFS is unregistered, another VFS is chosen as

5853 ** the default. The choice for the new VFS is arbitrary.)^

5854 */

5855 sqlite3_vfs sqlite3_vfs_find(const char zVfsName);

5856 int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);

5857 int sqlite3_vfs_unregister(sqlite3_vfs*);

5858

5859 /*

5860 ** CAPI3REF: Mutexes

5861 **

5862 ** The SQLite core uses these routines for thread

5863 ** synchronization. Though they are intended for internal

5864 ** use by SQLite, code that links against SQLite is

5865 ** permitted to use any of these routines.

5866 **

5867 ** The SQLite source code contains multiple implementations

5868 ** of these mutex routines. An appropriate implementation

5869 ** is selected automatically at compile-time. ^(The following

5870 ** implementations are available in the SQLite core:

5871 **

5872 ** <ul>

5873 ** <li> SQLITE_MUTEX_PTHREADS

5874 ** <li> SQLITE_MUTEX_W32

5875 ** <li> SQLITE_MUTEX_NOOP

5876 ** </ul>)^

5877 **

5878 ** ^The SQLITE_MUTEX_NOOP implementation is a set of routines

5879 ** that does no real locking and is appropriate for use in

5880 ** a single-threaded application. ^The SQLITE_MUTEX_PTHREADS and

5881 ** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix

5882 ** and Windows.

5883 **

5884 ** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor

5885 ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex

5886 ** implementation is included with the library. In this case the

5887 ** application must supply a custom mutex implementation using the

5888 ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function

5889 ** before calling sqlite3_initialize() or any other public sqlite3_

5890 ** function that calls sqlite3_initialize().)^

5891 **

5892 ** ^The sqlite3_mutex_alloc() routine allocates a new

5893 ** mutex and returns a pointer to it. ^If it returns NULL

5894 ** that means that a mutex could not be allocated. ^SQLite

5895 ** will unwind its stack and return an error. ^(The argument

5896 ** to sqlite3_mutex_alloc() is one of these integer constants:

5897 **

5898 ** <ul>

5899 ** <li> SQLITE_MUTEX_FAST

5900 ** <li> SQLITE_MUTEX_RECURSIVE

5901 ** <li> SQLITE_MUTEX_STATIC_MASTER

5902 ** <li> SQLITE_MUTEX_STATIC_MEM

5903 ** <li> SQLITE_MUTEX_STATIC_OPEN

5904 ** <li> SQLITE_MUTEX_STATIC_PRNG

5905 ** <li> SQLITE_MUTEX_STATIC_LRU

5906 ** <li> SQLITE_MUTEX_STATIC_PMEM

5907 ** <li> SQLITE_MUTEX_STATIC_APP1

5908 ** <li> SQLITE_MUTEX_STATIC_APP2

5909 ** </ul>)^

5910 **

5911 ** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)

5912 ** cause sqlite3_mutex_alloc() to create

5913 ** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE

5914 ** is used but not necessarily so when SQLITE_MUTEX_FAST is used.

5915 ** The mutex implementation does not need to make a distinction

5916 ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does

5917 ** not want to. ^SQLite will only request a recursive mutex in

5918 ** cases where it really needs one. ^If a faster non-recursive mutex

5919 ** implementation is available on the host platform, the mutex subsystem

5920 ** might return such a mutex in response to SQLITE_MUTEX_FAST.

5921 **

5922 ** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other

5923 ** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return

5924 ** a pointer to a static preexisting mutex. ^Six static mutexes are

5925 ** used by the current version of SQLite. Future versions of SQLite

5926 ** may add additional static mutexes. Static mutexes are for internal

5927 ** use by SQLite only. Applications that use SQLite mutexes should

5928 ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or

5929 ** SQLITE_MUTEX_RECURSIVE.

5930 **

5931 ** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST

5932 ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()

5933 ** returns a different mutex on every call. ^But for the static

5934 ** mutex types, the same mutex is returned on every call that has

5935 ** the same type number.

5936 **

5937 ** ^The sqlite3_mutex_free() routine deallocates a previously

5938 ** allocated dynamic mutex. ^SQLite is careful to deallocate every

5939 ** dynamic mutex that it allocates. The dynamic mutexes must not be in

5940 ** use when they are deallocated. Attempting to deallocate a static

5941 ** mutex results in undefined behavior. ^SQLite never deallocates

5942 ** a static mutex.

5943 **

5944 ** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt

5945 ** to enter a mutex. ^If another thread is already within the mutex,

5946 ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return

5947 ** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK]

5948 ** upon successful entry. ^(Mutexes created using

5949 ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.

5950 ** In such cases the,

5951 ** mutex must be exited an equal number of times before another thread

5952 ** can enter.)^ ^(If the same thread tries to enter any other

5953 ** kind of mutex more than once, the behavior is undefined.

5954 ** SQLite will never exhibit

5955 ** such behavior in its own use of mutexes.)^

5956 **

5957 ** ^(Some systems (for example, Windows 95) do not support the operation

5958 ** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try()

5959 ** will always return SQLITE_BUSY. The SQLite core only ever uses

5960 ** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^

5961 **

5962 ** ^The sqlite3_mutex_leave() routine exits a mutex that was

5963 ** previously entered by the same thread. ^(The behavior

5964 ** is undefined if the mutex is not currently entered by the

5965 ** calling thread or is not currently allocated. SQLite will

5966 ** never do either.)^

5967 **

5968 ** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or

5969 ** sqlite3_mutex_leave() is a NULL pointer, then all three routines

5970 ** behave as no-ops.

5971 **

5972 ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].

5973 */

5974 sqlite3_mutex *sqlite3_mutex_alloc(int);

5975 void sqlite3_mutex_free(sqlite3_mutex*);

5976 void sqlite3_mutex_enter(sqlite3_mutex*);

5977 int sqlite3_mutex_try(sqlite3_mutex*);

5978 void sqlite3_mutex_leave(sqlite3_mutex*);

5979

5980 /*

5981 ** CAPI3REF: Mutex Methods Object

5982 **

5983 ** An instance of this structure defines the low-level routines

5984 ** used to allocate and use mutexes.

5985 **

5986 ** Usually, the default mutex implementations provided by SQLite are

5987 ** sufficient, however the user has the option of substituting a custom

5988 ** implementation for specialized deployments or systems for which SQLite

5989 ** does not provide a suitable implementation. In this case, the user

5990 ** creates and populates an instance of this structure to pass

5991 ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.

5992 ** Additionally, an instance of this structure can be used as an

5993 ** output variable when querying the system for the current mutex

5994 ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.

5995 **

5996 ** ^The xMutexInit method defined by this structure is invoked as

5997 ** part of system initialization by the sqlite3_initialize() function.

5998 ** ^The xMutexInit routine is called by SQLite exactly once for each

5999 ** effective call to [sqlite3_initialize()].

6000 **

6001 ** ^The xMutexEnd method defined by this structure is invoked as

6002 ** part of system shutdown by the sqlite3_shutdown() function. The

6003 ** implementation of this method is expected to release all outstanding

6004 ** resources obtained by the mutex methods implementation, especially

6005 ** those obtained by the xMutexInit method. ^The xMutexEnd()

6006 ** interface is invoked exactly once for each call to [sqlite3_shutdown()].

6007 **

6008 ** ^(The remaining seven methods defined by this structure (xMutexAlloc,

6009 ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and

6010 ** xMutexNotheld) implement the following interfaces (respectively):

6011 **

6012 ** <ul>

6013 ** <li> [sqlite3_mutex_alloc()] </li>

6014 ** <li> [sqlite3_mutex_free()] </li>

6015 ** <li> [sqlite3_mutex_enter()] </li>

6016 ** <li> [sqlite3_mutex_try()] </li>

6017 ** <li> [sqlite3_mutex_leave()] </li>

6018 ** <li> [sqlite3_mutex_held()] </li>

6019 ** <li> [sqlite3_mutex_notheld()] </li>

6020 ** </ul>)^

6021 **

6022 ** The only difference is that the public sqlite3_XXX functions enumerated

6023 ** above silently ignore any invocations that pass a NULL pointer instead

6024 ** of a valid mutex handle. The implementations of the methods defined

6025 ** by this structure are not required to handle this case, the results

6026 ** of passing a NULL pointer instead of a valid mutex handle are undefined

6027 ** (i.e. it is acceptable to provide an implementation that segfaults if

6028 ** it is passed a NULL pointer).

6029 **

6030 ** The xMutexInit() method must be threadsafe. ^It must be harmless to

6031 ** invoke xMutexInit() multiple times within the same process and without

6032 ** intervening calls to xMutexEnd(). Second and subsequent calls to

6033 ** xMutexInit() must be no-ops.

6034 **

6035 ** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]

6036 ** and its associates). ^Similarly, xMutexAlloc() must not use SQLite memory

6037 ** allocation for a static mutex. ^However xMutexAlloc() may use SQLite

6038 ** memory allocation for a fast or recursive mutex.

6039 **

6040 ** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is

6041 ** called, but only if the prior call to xMutexInit returned SQLITE_OK.

6042 ** If xMutexInit fails in any way, it is expected to clean up after itself

6043 ** prior to returning.

6044 */

6045 typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;

6046 struct sqlite3_mutex_methods {

6047 int (*xMutexInit)(void);

6048 int (*xMutexEnd)(void);

6049 sqlite3_mutex (xMutexAlloc)(int);

6050 void (xMutexFree)(sqlite3_mutex );

6051 void (xMutexEnter)(sqlite3_mutex );

6052 int (xMutexTry)(sqlite3_mutex );

6053 void (xMutexLeave)(sqlite3_mutex );

6054 int (xMutexHeld)(sqlite3_mutex );

6055 int (xMutexNotheld)(sqlite3_mutex );

6056 };

6057

6058 /*

6059 ** CAPI3REF: Mutex Verification Routines

6060 **

6061 ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines

6062 ** are intended for use inside assert() statements. ^The SQLite core

6063 ** never uses these routines except inside an assert() and applications

6064 ** are advised to follow the lead of the core. ^The SQLite core only

6065 ** provides implementations for these routines when it is compiled

6066 ** with the SQLITE_DEBUG flag. ^External mutex implementations

6067 ** are only required to provide these routines if SQLITE_DEBUG is

6068 ** defined and if NDEBUG is not defined.

6069 **

6070 ** ^These routines should return true if the mutex in their argument

6071 ** is held or not held, respectively, by the calling thread.

6072 **

6073 ** ^The implementation is not required to provide versions of these

6074 ** routines that actually work. If the implementation does not provide working

6075 ** versions of these routines, it should at least provide stubs that always

6076 ** return true so that one does not get spurious assertion failures.

6077 **

6078 ** ^If the argument to sqlite3_mutex_held() is a NULL pointer then

6079 ** the routine should return 1. This seems counter-intuitive since

6080 ** clearly the mutex cannot be held if it does not exist. But

6081 ** the reason the mutex does not exist is because the build is not

6082 ** using mutexes. And we do not want the assert() containing the

6083 ** call to sqlite3_mutex_held() to fail, so a non-zero return is

6084 ** the appropriate thing to do. ^The sqlite3_mutex_notheld()

6085 ** interface should also return 1 when given a NULL pointer.

6086 */

6087 #ifndef NDEBUG

6088 int sqlite3_mutex_held(sqlite3_mutex*);

6089 int sqlite3_mutex_notheld(sqlite3_mutex*);

6090 #endif

6091

6092 /*

6093 ** CAPI3REF: Mutex Types

6094 **

6095 ** The [sqlite3_mutex_alloc()] interface takes a single argument

6096 ** which is one of these integer constants.

6097 **

6098 ** The set of static mutexes may change from one SQLite release to the

6099 ** next. Applications that override the built-in mutex logic must be

6100 ** prepared to accommodate additional static mutexes.

6101 */

6102 #define SQLITE_MUTEX_FAST 0

6103 #define SQLITE_MUTEX_RECURSIVE 1

6104 #define SQLITE_MUTEX_STATIC_MASTER 2

6105 #define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */

6106 #define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */

6107 #define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */

6108 #define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */

6109 #define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */

6110 #define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */

6111 #define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */

6112 #define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */

6113 #define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */

6114 #define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */

6115

6116 /*

6117 ** CAPI3REF: Retrieve the mutex for a database connection

6118 **

6119 ** ^This interface returns a pointer the [sqlite3_mutex] object that

6120 ** serializes access to the [database connection] given in the argument

6121 ** when the [threading mode] is Serialized.

6122 ** ^If the [threading mode] is Single-thread or Multi-thread then this

6123 ** routine returns a NULL pointer.

6124 */

6125 sqlite3_mutex sqlite3_db_mutex(sqlite3);

6126

6127 /*

6128 ** CAPI3REF: Low-Level Control Of Database Files

6129 **

6130 ** ^The [sqlite3_file_control()] interface makes a direct call to the

6131 ** xFileControl method for the [sqlite3_io_methods] object associated

6132 ** with a particular database identified by the second argument. ^The

6133 ** name of the database is "main" for the main database or "temp" for the

6134 ** TEMP database, or the name that appears after the AS keyword for

6135 ** databases that are added using the [ATTACH] SQL command.

6136 ** ^A NULL pointer can be used in place of "main" to refer to the

6137 ** main database file.

6138 ** ^The third and fourth parameters to this routine

6139 ** are passed directly through to the second and third parameters of

6140 ** the xFileControl method. ^The return value of the xFileControl

6141 ** method becomes the return value of this routine.

6142 **

6143 ** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes

6144 ** a pointer to the underlying [sqlite3_file] object to be written into

6145 ** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER

6146 ** case is a short-circuit path which does not actually invoke the

6147 ** underlying sqlite3_io_methods.xFileControl method.

6148 **

6149 ** ^If the second parameter (zDbName) does not match the name of any

6150 ** open database file, then SQLITE_ERROR is returned. ^This error

6151 ** code is not remembered and will not be recalled by [sqlite3_errcode()]

6152 ** or [sqlite3_errmsg()]. The underlying xFileControl method might

6153 ** also return SQLITE_ERROR. There is no way to distinguish between

6154 ** an incorrect zDbName and an SQLITE_ERROR return from the underlying

6155 ** xFileControl method.

6156 **

6157 ** See also: [SQLITE_FCNTL_LOCKSTATE]

6158 */

6159 int sqlite3_file_control(sqlite3, const char zDbName, int op, void*);

6160

6161 /*

6162 ** CAPI3REF: Testing Interface

6163 **

6164 ** ^The sqlite3_test_control() interface is used to read out internal

6165 ** state of SQLite and to inject faults into SQLite for testing

6166 ** purposes. ^The first parameter is an operation code that determines

6167 ** the number, meaning, and operation of all subsequent parameters.

6168 **

6169 ** This interface is not for use by applications. It exists solely

6170 ** for verifying the correct operation of the SQLite library. Depending

6171 ** on how the SQLite library is compiled, this interface might not exist.

6172 **

6173 ** The details of the operation codes, their meanings, the parameters

6174 ** they take, and what they do are all subject to change without notice.

6175 ** Unlike most of the SQLite API, this function is not guaranteed to

6176 ** operate consistently from one release to the next.

6177 */

6178 int sqlite3_test_control(int op, ...);

6179

6180 /*

6181 ** CAPI3REF: Testing Interface Operation Codes

6182 **

6183 ** These constants are the valid operation code parameters used

6184 ** as the first argument to [sqlite3_test_control()].

6185 **

6186 ** These parameters and their meanings are subject to change

6187 ** without notice. These values are for testing purposes only.

6188 ** Applications should not use any of these parameters or the

6189 ** [sqlite3_test_control()] interface.

6190 */

6191 #define SQLITE_TESTCTRL_FIRST 5

6192 #define SQLITE_TESTCTRL_PRNG_SAVE 5

6193 #define SQLITE_TESTCTRL_PRNG_RESTORE 6

6194 #define SQLITE_TESTCTRL_PRNG_RESET 7

6195 #define SQLITE_TESTCTRL_BITVEC_TEST 8

6196 #define SQLITE_TESTCTRL_FAULT_INSTALL 9

6197 #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10

6198 #define SQLITE_TESTCTRL_PENDING_BYTE 11

6199 #define SQLITE_TESTCTRL_ASSERT 12

6200 #define SQLITE_TESTCTRL_ALWAYS 13

6201 #define SQLITE_TESTCTRL_RESERVE 14

6202 #define SQLITE_TESTCTRL_OPTIMIZATIONS 15

6203 #define SQLITE_TESTCTRL_ISKEYWORD 16

6204 #define SQLITE_TESTCTRL_SCRATCHMALLOC 17

6205 #define SQLITE_TESTCTRL_LOCALTIME_FAULT 18

6206 #define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */

6207 #define SQLITE_TESTCTRL_NEVER_CORRUPT 20

6208 #define SQLITE_TESTCTRL_VDBE_COVERAGE 21

6209 #define SQLITE_TESTCTRL_BYTEORDER 22

6210 #define SQLITE_TESTCTRL_ISINIT 23

6211 #define SQLITE_TESTCTRL_SORTER_MMAP 24

6212 #define SQLITE_TESTCTRL_LAST 24

6213

6214 /*

6215 ** CAPI3REF: SQLite Runtime Status

6216 **

6217 ** ^This interface is used to retrieve runtime status information

6218 ** about the performance of SQLite, and optionally to reset various

6219 ** highwater marks. ^The first argument is an integer code for

6220 ** the specific parameter to measure. ^(Recognized integer codes

6221 ** are of the form [status parameters \| SQLITE_STATUS_...].)^

6222 ** ^The current value of the parameter is returned into *pCurrent.

6223 ** ^The highest recorded value is returned in *pHighwater. ^If the

6224 ** resetFlag is true, then the highest record value is reset after

6225 ** *pHighwater is written. ^(Some parameters do not record the highest

6226 ** value. For those parameters

6227 ** nothing is written into *pHighwater and the resetFlag is ignored.)^

6228 ** ^(Other parameters record only the highwater mark and not the current

6229 ** value. For these latter parameters nothing is written into *pCurrent.)^

6230 **

6231 ** ^The sqlite3_status() routine returns SQLITE_OK on success and a

6232 ** non-zero [error code] on failure.

6233 **

6234 ** This routine is threadsafe but is not atomic. This routine can be

6235 ** called while other threads are running the same or different SQLite

6236 ** interfaces. However the values returned in *pCurrent and

6237 ** *pHighwater reflect the status of SQLite at different points in time

6238 ** and it is possible that another thread might change the parameter

6239 ** in between the times when pCurrent and pHighwater are written.

6240 **

6241 ** See also: [sqlite3_db_status()]

6242 */

6243 int sqlite3_status(int op, int pCurrent, int pHighwater, int resetFlag);

6244

6245

6246 /*

6247 ** CAPI3REF: Status Parameters

6248 ** KEYWORDS: {status parameters}

6249 **

6250 ** These integer constants designate various run-time status parameters

6251 ** that can be returned by [sqlite3_status()].

6252 **

6253 ** <dl>

6254 ** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>

6255 ** <dd>This parameter is the current amount of memory checked out

6256 ** using [sqlite3_malloc()], either directly or indirectly. The

6257 ** figure includes calls made to [sqlite3_malloc()] by the application

6258 ** and internal memory usage by the SQLite library. Scratch memory

6259 ** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache

6260 ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in

6261 ** this parameter. The amount returned is the sum of the allocation

6262 ** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^

6263 **

6264 ** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>

6265 ** <dd>This parameter records the largest memory allocation request

6266 ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their

6267 ** internal equivalents). Only the value returned in the

6268 ** *pHighwater parameter to [sqlite3_status()] is of interest.

6269 ** The value written into the *pCurrent parameter is undefined.</dd>)^

6270 **

6271 ** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>

6272 ** <dd>This parameter records the number of separate memory allocations

6273 ** currently checked out.</dd>)^

6274 **

6275 ** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>

6276 ** <dd>This parameter returns the number of pages used out of the

6277 ** [pagecache memory allocator] that was configured using

6278 ** [SQLITE_CONFIG_PAGECACHE]. The

6279 ** value returned is in pages, not in bytes.</dd>)^

6280 **

6281 ** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]]

6282 ** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>

6283 ** <dd>This parameter returns the number of bytes of page cache

6284 ** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]

6285 ** buffer and where forced to overflow to [sqlite3_malloc()]. The

6286 ** returned value includes allocations that overflowed because they

6287 ** where too large (they were larger than the "sz" parameter to

6288 ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because

6289 ** no space was left in the page cache.</dd>)^

6290 **

6291 ** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>

6292 ** <dd>This parameter records the largest memory allocation request

6293 ** handed to [pagecache memory allocator]. Only the value returned in the

6294 ** *pHighwater parameter to [sqlite3_status()] is of interest.

6295 ** The value written into the *pCurrent parameter is undefined.</dd>)^

6296 **

6297 ** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt>

6298 ** <dd>This parameter returns the number of allocations used out of the

6299 ** [scratch memory allocator] configured using

6300 ** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not

6301 ** in bytes. Since a single thread may only have one scratch allocation

6302 ** outstanding at time, this parameter also reports the number of threads

6303 ** using scratch memory at the same time.</dd>)^

6304 **

6305 ** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>

6306 ** <dd>This parameter returns the number of bytes of scratch memory

6307 ** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH]

6308 ** buffer and where forced to overflow to [sqlite3_malloc()]. The values

6309 ** returned include overflows because the requested allocation was too

6310 ** larger (that is, because the requested allocation was larger than the

6311 ** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer

6312 ** slots were available.

6313 ** </dd>)^

6314 **

6315 ** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt>

6316 ** <dd>This parameter records the largest memory allocation request

6317 ** handed to [scratch memory allocator]. Only the value returned in the

6318 ** *pHighwater parameter to [sqlite3_status()] is of interest.

6319 ** The value written into the *pCurrent parameter is undefined.</dd>)^

6320 **

6321 ** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>

6322 ** <dd>This parameter records the deepest parser stack. It is only

6323 ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^

6324 ** </dl>

6325 **

6326 ** New status parameters may be added from time to time.

6327 */

6328 #define SQLITE_STATUS_MEMORY_USED 0

6329 #define SQLITE_STATUS_PAGECACHE_USED 1

6330 #define SQLITE_STATUS_PAGECACHE_OVERFLOW 2

6331 #define SQLITE_STATUS_SCRATCH_USED 3

6332 #define SQLITE_STATUS_SCRATCH_OVERFLOW 4

6333 #define SQLITE_STATUS_MALLOC_SIZE 5

6334 #define SQLITE_STATUS_PARSER_STACK 6

6335 #define SQLITE_STATUS_PAGECACHE_SIZE 7

6336 #define SQLITE_STATUS_SCRATCH_SIZE 8

6337 #define SQLITE_STATUS_MALLOC_COUNT 9

6338

6339 /*

6340 ** CAPI3REF: Database Connection Status

6341 **

6342 ** ^This interface is used to retrieve runtime status information

6343 ** about a single [database connection]. ^The first argument is the

6344 ** database connection object to be interrogated. ^The second argument

6345 ** is an integer constant, taken from the set of

6346 ** [SQLITE_DBSTATUS options], that

6347 ** determines the parameter to interrogate. The set of

6348 ** [SQLITE_DBSTATUS options] is likely

6349 ** to grow in future releases of SQLite.

6350 **

6351 ** ^The current value of the requested parameter is written into *pCur

6352 ** and the highest instantaneous value is written into *pHiwtr. ^If

6353 ** the resetFlg is true, then the highest instantaneous value is

6354 ** reset back down to the current value.

6355 **

6356 ** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a

6357 ** non-zero [error code] on failure.

6358 **

6359 ** See also: [sqlite3_status()] and [sqlite3_stmt_status()].

6360 */

6361 int sqlite3_db_status(sqlite3, int op, int pCur, int *pHiwtr, int resetFlg);

6362

6363 /*

6364 ** CAPI3REF: Status Parameters for database connections

6365 ** KEYWORDS: {SQLITE_DBSTATUS options}

6366 **

6367 ** These constants are the available integer "verbs" that can be passed as

6368 ** the second argument to the [sqlite3_db_status()] interface.

6369 **

6370 ** New verbs may be added in future releases of SQLite. Existing verbs

6371 ** might be discontinued. Applications should check the return code from

6372 ** [sqlite3_db_status()] to make sure that the call worked.

6373 ** The [sqlite3_db_status()] interface will return a non-zero error code

6374 ** if a discontinued or unsupported verb is invoked.

6375 **

6376 ** <dl>

6377 ** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>

6378 ** <dd>This parameter returns the number of lookaside memory slots currently

6379 ** checked out.</dd>)^

6380 **

6381 ** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>

6382 ** <dd>This parameter returns the number malloc attempts that were

6383 ** satisfied using lookaside memory. Only the high-water value is meaningful;

6384 ** the current value is always zero.)^

6385 **

6386 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]]

6387 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>

6388 ** <dd>This parameter returns the number malloc attempts that might have

6389 ** been satisfied using lookaside memory but failed due to the amount of

6390 ** memory requested being larger than the lookaside slot size.

6391 ** Only the high-water value is meaningful;

6392 ** the current value is always zero.)^

6393 **

6394 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]]

6395 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>

6396 ** <dd>This parameter returns the number malloc attempts that might have

6397 ** been satisfied using lookaside memory but failed due to all lookaside

6398 ** memory already being in use.

6399 ** Only the high-water value is meaningful;

6400 ** the current value is always zero.)^

6401 **

6402 ** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>

6403 ** <dd>This parameter returns the approximate number of bytes of heap

6404 ** memory used by all pager caches associated with the database connection.)^

6405 ** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.

6406 **

6407 ** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>

6408 ** <dd>This parameter returns the approximate number of bytes of heap

6409 ** memory used to store the schema for all databases associated

6410 ** with the connection - main, temp, and any [ATTACH]-ed databases.)^

6411 ** ^The full amount of memory used by the schemas is reported, even if the

6412 ** schema memory is shared with other database connections due to

6413 ** [shared cache mode] being enabled.

6414 ** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.

6415 **

6416 ** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>

6417 ** <dd>This parameter returns the approximate number of bytes of heap

6418 ** and lookaside memory used by all prepared statements associated with

6419 ** the database connection.)^

6420 ** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.

6421 ** </dd>

6422 **

6423 ** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt>

6424 ** <dd>This parameter returns the number of pager cache hits that have

6425 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT

6426 ** is always 0.

6427 ** </dd>

6428 **

6429 ** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt>

6430 ** <dd>This parameter returns the number of pager cache misses that have

6431 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS

6432 ** is always 0.

6433 ** </dd>

6434 **

6435 ** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt>

6436 ** <dd>This parameter returns the number of dirty cache entries that have

6437 ** been written to disk. Specifically, the number of pages written to the

6438 ** wal file in wal mode databases, or the number of pages written to the

6439 ** database file in rollback mode databases. Any pages written as part of

6440 ** transaction rollback or database recovery operations are not included.

6441 ** If an IO or other error occurs while writing a page to disk, the effect

6442 ** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The

6443 ** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0.

6444 ** </dd>

6445 **

6446 ** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt>

6447 ** <dd>This parameter returns zero for the current value if and only if

6448 ** all foreign key constraints (deferred or immediate) have been

6449 ** resolved.)^ ^The highwater mark is always 0.

6450 ** </dd>

6451 ** </dl>

6452 */

6453 #define SQLITE_DBSTATUS_LOOKASIDE_USED 0

6454 #define SQLITE_DBSTATUS_CACHE_USED 1

6455 #define SQLITE_DBSTATUS_SCHEMA_USED 2

6456 #define SQLITE_DBSTATUS_STMT_USED 3

6457 #define SQLITE_DBSTATUS_LOOKASIDE_HIT 4

6458 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5

6459 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6

6460 #define SQLITE_DBSTATUS_CACHE_HIT 7

6461 #define SQLITE_DBSTATUS_CACHE_MISS 8

6462 #define SQLITE_DBSTATUS_CACHE_WRITE 9

6463 #define SQLITE_DBSTATUS_DEFERRED_FKS 10

6464 #define SQLITE_DBSTATUS_MAX 10 /* Largest defined DBSTATUS */

6465

6466

6467 /*

6468 ** CAPI3REF: Prepared Statement Status

6469 **

6470 ** ^(Each prepared statement maintains various

6471 ** [SQLITE_STMTSTATUS counters] that measure the number

6472 ** of times it has performed specific operations.)^ These counters can

6473 ** be used to monitor the performance characteristics of the prepared

6474 ** statements. For example, if the number of table steps greatly exceeds

6475 ** the number of table searches or result rows, that would tend to indicate

6476 ** that the prepared statement is using a full table scan rather than

6477 ** an index.

6478 **

6479 ** ^(This interface is used to retrieve and reset counter values from

6480 ** a [prepared statement]. The first argument is the prepared statement

6481 ** object to be interrogated. The second argument

6482 ** is an integer code for a specific [SQLITE_STMTSTATUS counter]

6483 ** to be interrogated.)^

6484 ** ^The current value of the requested counter is returned.

6485 ** ^If the resetFlg is true, then the counter is reset to zero after this

6486 ** interface call returns.

6487 **

6488 ** See also: [sqlite3_status()] and [sqlite3_db_status()].

6489 */

6490 int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);

6491

6492 /*

6493 ** CAPI3REF: Status Parameters for prepared statements

6494 ** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters}

6495 **

6496 ** These preprocessor macros define integer codes that name counter

6497 ** values associated with the [sqlite3_stmt_status()] interface.

6498 ** The meanings of the various counters are as follows:

6499 **

6500 ** <dl>

6501 ** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>

6502 ** <dd>^This is the number of times that SQLite has stepped forward in

6503 ** a table as part of a full table scan. Large numbers for this counter

6504 ** may indicate opportunities for performance improvement through

6505 ** careful use of indices.</dd>

6506 **

6507 ** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt>

6508 ** <dd>^This is the number of sort operations that have occurred.

6509 ** A non-zero value in this counter may indicate an opportunity to

6510 ** improvement performance through careful use of indices.</dd>

6511 **

6512 ** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>

6513 ** <dd>^This is the number of rows inserted into transient indices that

6514 ** were created automatically in order to help joins run faster.

6515 ** A non-zero value in this counter may indicate an opportunity to

6516 ** improvement performance by adding permanent indices that do not

6517 ** need to be reinitialized each time the statement is run.</dd>

6518 **

6519 ** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt>

6520 ** <dd>^This is the number of virtual machine operations executed

6521 ** by the prepared statement if that number is less than or equal

6522 ** to 2147483647. The number of virtual machine operations can be

6523 ** used as a proxy for the total work done by the prepared statement.

6524 ** If the number of virtual machine operations exceeds 2147483647

6525 ** then the value returned by this statement status code is undefined.

6526 ** </dd>

6527 ** </dl>

6528 */

6529 #define SQLITE_STMTSTATUS_FULLSCAN_STEP 1

6530 #define SQLITE_STMTSTATUS_SORT 2

6531 #define SQLITE_STMTSTATUS_AUTOINDEX 3

6532 #define SQLITE_STMTSTATUS_VM_STEP 4

6533

6534 /*

6535 ** CAPI3REF: Custom Page Cache Object

6536 **

6537 ** The sqlite3_pcache type is opaque. It is implemented by

6538 ** the pluggable module. The SQLite core has no knowledge of

6539 ** its size or internal structure and never deals with the

6540 ** sqlite3_pcache object except by holding and passing pointers

6541 ** to the object.

6542 **

6543 ** See [sqlite3_pcache_methods2] for additional information.

6544 */

6545 typedef struct sqlite3_pcache sqlite3_pcache;

6546

6547 /*

6548 ** CAPI3REF: Custom Page Cache Object

6549 **

6550 ** The sqlite3_pcache_page object represents a single page in the

6551 ** page cache. The page cache will allocate instances of this

6552 ** object. Various methods of the page cache use pointers to instances

6553 ** of this object as parameters or as their return value.

6554 **

6555 ** See [sqlite3_pcache_methods2] for additional information.

6556 */

6557 typedef struct sqlite3_pcache_page sqlite3_pcache_page;

6558 struct sqlite3_pcache_page {

6559 void pBuf; / The content of the page */

6560 void pExtra; / Extra information associated with the page */

6561 };

6562

6563 /*

6564 ** CAPI3REF: Application Defined Page Cache.

6565 ** KEYWORDS: {page cache}

6566 **

6567 ** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can

6568 ** register an alternative page cache implementation by passing in an

6569 ** instance of the sqlite3_pcache_methods2 structure.)^

6570 ** In many applications, most of the heap memory allocated by

6571 ** SQLite is used for the page cache.

6572 ** By implementing a

6573 ** custom page cache using this API, an application can better control

6574 ** the amount of memory consumed by SQLite, the way in which

6575 ** that memory is allocated and released, and the policies used to

6576 ** determine exactly which parts of a database file are cached and for

6577 ** how long.

6578 **

6579 ** The alternative page cache mechanism is an

6580 ** extreme measure that is only needed by the most demanding applications.

6581 ** The built-in page cache is recommended for most uses.

6582 **

6583 ** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an

6584 ** internal buffer by SQLite within the call to [sqlite3_config]. Hence

6585 ** the application may discard the parameter after the call to

6586 ** [sqlite3_config()] returns.)^

6587 **

6588 ** [[the xInit() page cache method]]

6589 ** ^(The xInit() method is called once for each effective

6590 ** call to [sqlite3_initialize()])^

6591 ** (usually only once during the lifetime of the process). ^(The xInit()

6592 ** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^

6593 ** The intent of the xInit() method is to set up global data structures

6594 ** required by the custom page cache implementation.

6595 ** ^(If the xInit() method is NULL, then the

6596 ** built-in default page cache is used instead of the application defined

6597 ** page cache.)^

6598 **

6599 ** [[the xShutdown() page cache method]]

6600 ** ^The xShutdown() method is called by [sqlite3_shutdown()].

6601 ** It can be used to clean up

6602 ** any outstanding resources before process shutdown, if required.

6603 ** ^The xShutdown() method may be NULL.

6604 **

6605 ** ^SQLite automatically serializes calls to the xInit method,

6606 ** so the xInit method need not be threadsafe. ^The

6607 ** xShutdown method is only called from [sqlite3_shutdown()] so it does

6608 ** not need to be threadsafe either. All other methods must be threadsafe

6609 ** in multithreaded applications.

6610 **

6611 ** ^SQLite will never invoke xInit() more than once without an intervening

6612 ** call to xShutdown().

6613 **

6614 ** [[the xCreate() page cache methods]]

6615 ** ^SQLite invokes the xCreate() method to construct a new cache instance.

6616 ** SQLite will typically create one cache instance for each open database file,

6617 ** though this is not guaranteed. ^The

6618 ** first parameter, szPage, is the size in bytes of the pages that must

6619 ** be allocated by the cache. ^szPage will always a power of two. ^The

6620 ** second parameter szExtra is a number of bytes of extra storage

6621 ** associated with each page cache entry. ^The szExtra parameter will

6622 ** a number less than 250. SQLite will use the

6623 ** extra szExtra bytes on each page to store metadata about the underlying

6624 ** database page on disk. The value passed into szExtra depends

6625 ** on the SQLite version, the target platform, and how SQLite was compiled.

6626 ** ^The third argument to xCreate(), bPurgeable, is true if the cache being

6627 ** created will be used to cache database pages of a file stored on disk, or

6628 ** false if it is used for an in-memory database. The cache implementation

6629 ** does not have to do anything special based with the value of bPurgeable;

6630 ** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will

6631 ** never invoke xUnpin() except to deliberately delete a page.

6632 ** ^In other words, calls to xUnpin() on a cache with bPurgeable set to

6633 ** false will always have the "discard" flag set to true.

6634 ** ^Hence, a cache created with bPurgeable false will

6635 ** never contain any unpinned pages.

6636 **

6637 ** [[the xCachesize() page cache method]]

6638 ** ^(The xCachesize() method may be called at any time by SQLite to set the

6639 ** suggested maximum cache-size (number of pages stored by) the cache

6640 ** instance passed as the first argument. This is the value configured using

6641 ** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable

6642 ** parameter, the implementation is not required to do anything with this

6643 ** value; it is advisory only.

6644 **

6645 ** [[the xPagecount() page cache methods]]

6646 ** The xPagecount() method must return the number of pages currently

6647 ** stored in the cache, both pinned and unpinned.

6648 **

6649 ** [[the xFetch() page cache methods]]

6650 ** The xFetch() method locates a page in the cache and returns a pointer to

6651 ** an sqlite3_pcache_page object associated with that page, or a NULL pointer.

6652 ** The pBuf element of the returned sqlite3_pcache_page object will be a

6653 ** pointer to a buffer of szPage bytes used to store the content of a

6654 ** single database page. The pExtra element of sqlite3_pcache_page will be

6655 ** a pointer to the szExtra bytes of extra storage that SQLite has requested

6656 ** for each entry in the page cache.

6657 **

6658 ** The page to be fetched is determined by the key. ^The minimum key value

6659 ** is 1. After it has been retrieved using xFetch, the page is considered

6660 ** to be "pinned".

6661 **

6662 ** If the requested page is already in the page cache, then the page cache

6663 ** implementation must return a pointer to the page buffer with its content

6664 ** intact. If the requested page is not already in the cache, then the

6665 ** cache implementation should use the value of the createFlag

6666 ** parameter to help it determined what action to take:

6667 **

6668 ** <table border=1 width=85% align=center>

6669 ** <tr><th> createFlag <th> Behavior when page is not already in cache

6670 ** <tr><td> 0 <td> Do not allocate a new page. Return NULL.

6671 ** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.

6672 ** Otherwise return NULL.

6673 ** <tr><td> 2 <td> Make every effort to allocate a new page. Only return

6674 ** NULL if allocating a new page is effectively impossible.

6675 ** </table>

6676 **

6677 ** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite

6678 ** will only use a createFlag of 2 after a prior call with a createFlag of 1

6679 ** failed.)^ In between the to xFetch() calls, SQLite may

6680 ** attempt to unpin one or more cache pages by spilling the content of

6681 ** pinned pages to disk and synching the operating system disk cache.

6682 **

6683 ** [[the xUnpin() page cache method]]

6684 ** ^xUnpin() is called by SQLite with a pointer to a currently pinned page

6685 ** as its second argument. If the third parameter, discard, is non-zero,

6686 ** then the page must be evicted from the cache.

6687 ** ^If the discard parameter is

6688 ** zero, then the page may be discarded or retained at the discretion of

6689 ** page cache implementation. ^The page cache implementation

6690 ** may choose to evict unpinned pages at any time.

6691 **

6692 ** The cache must not perform any reference counting. A single

6693 ** call to xUnpin() unpins the page regardless of the number of prior calls

6694 ** to xFetch().

6695 **

6696 ** [[the xRekey() page cache methods]]

6697 ** The xRekey() method is used to change the key value associated with the

6698 ** page passed as the second argument. If the cache

6699 ** previously contains an entry associated with newKey, it must be

6700 ** discarded. ^Any prior cache entry associated with newKey is guaranteed not

6701 ** to be pinned.

6702 **

6703 ** When SQLite calls the xTruncate() method, the cache must discard all

6704 ** existing cache entries with page numbers (keys) greater than or equal

6705 ** to the value of the iLimit parameter passed to xTruncate(). If any

6706 ** of these pages are pinned, they are implicitly unpinned, meaning that

6707 ** they can be safely discarded.

6708 **

6709 ** [[the xDestroy() page cache method]]

6710 ** ^The xDestroy() method is used to delete a cache allocated by xCreate().

6711 ** All resources associated with the specified cache should be freed. ^After

6712 ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]

6713 ** handle invalid, and will not use it with any other sqlite3_pcache_methods2

6714 ** functions.

6715 **

6716 ** [[the xShrink() page cache method]]

6717 ** ^SQLite invokes the xShrink() method when it wants the page cache to

6718 ** free up as much of heap memory as possible. The page cache implementation

6719 ** is not obligated to free any memory, but well-behaved implementations should

6720 ** do their best.

6721 */

6722 typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;

6723 struct sqlite3_pcache_methods2 {

6724 int iVersion;

6725 void *pArg;

6726 int (xInit)(void);

6727 void (xShutdown)(void);

6728 sqlite3_pcache (xCreate)(int szPage, int szExtra, int bPurgeable);

6729 void (xCachesize)(sqlite3_pcache, int nCachesize);

6730 int (xPagecount)(sqlite3_pcache);

6731 sqlite3_pcache_page (xFetch)(sqlite3_pcache*, unsigned key, int createFlag);

6732 void (xUnpin)(sqlite3_pcache, sqlite3_pcache_page*, int discard);

6733 void (xRekey)(sqlite3_pcache, sqlite3_pcache_page*,

6734 unsigned oldKey, unsigned newKey);

6735 void (xTruncate)(sqlite3_pcache, unsigned iLimit);

6736 void (xDestroy)(sqlite3_pcache);

6737 void (xShrink)(sqlite3_pcache);

6738 };

6739

6740 /*

6741 ** This is the obsolete pcache_methods object that has now been replaced

6742 ** by sqlite3_pcache_methods2. This object is not used by SQLite. It is

6743 ** retained in the header file for backwards compatibility only.

6744 */

6745 typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;

6746 struct sqlite3_pcache_methods {

6747 void *pArg;

6748 int (xInit)(void);

6749 void (xShutdown)(void);

6750 sqlite3_pcache (xCreate)(int szPage, int bPurgeable);

6751 void (xCachesize)(sqlite3_pcache, int nCachesize);

6752 int (xPagecount)(sqlite3_pcache);

6753 void (xFetch)(sqlite3_pcache*, unsigned key, int createFlag);

6754 void (xUnpin)(sqlite3_pcache, void*, int discard);

6755 void (xRekey)(sqlite3_pcache, void*, unsigned oldKey, unsigned newKey);

6756 void (xTruncate)(sqlite3_pcache, unsigned iLimit);

6757 void (xDestroy)(sqlite3_pcache);

6758 };

6759

6760

6761 /*

6762 ** CAPI3REF: Online Backup Object

6763 **

6764 ** The sqlite3_backup object records state information about an ongoing

6765 ** online backup operation. ^The sqlite3_backup object is created by

6766 ** a call to [sqlite3_backup_init()] and is destroyed by a call to

6767 ** [sqlite3_backup_finish()].

6768 **

6769 ** See Also: [Using the SQLite Online Backup API]

6770 */

6771 typedef struct sqlite3_backup sqlite3_backup;

6772

6773 /*

6774 ** CAPI3REF: Online Backup API.

6775 **

6776 ** The backup API copies the content of one database into another.

6777 ** It is useful either for creating backups of databases or

6778 ** for copying in-memory databases to or from persistent files.

6779 **

6780 ** See Also: [Using the SQLite Online Backup API]

6781 **

6782 ** ^SQLite holds a write transaction open on the destination database file

6783 ** for the duration of the backup operation.

6784 ** ^The source database is read-locked only while it is being read;

6785 ** it is not locked continuously for the entire backup operation.

6786 ** ^Thus, the backup may be performed on a live source database without

6787 ** preventing other database connections from

6788 ** reading or writing to the source database while the backup is underway.

6789 **

6790 ** ^(To perform a backup operation:

6791 ** <ol>

6792 ** <li><b>sqlite3_backup_init()</b> is called once to initialize the

6793 ** backup,

6794 ** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer

6795 ** the data between the two databases, and finally

6796 ** <li><b>sqlite3_backup_finish()</b> is called to release all resources

6797 ** associated with the backup operation.

6798 ** </ol>)^

6799 ** There should be exactly one call to sqlite3_backup_finish() for each

6800 ** successful call to sqlite3_backup_init().

6801 **

6802 ** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>

6803 **

6804 ** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the

6805 ** [database connection] associated with the destination database

6806 ** and the database name, respectively.

6807 ** ^The database name is "main" for the main database, "temp" for the

6808 ** temporary database, or the name specified after the AS keyword in

6809 ** an [ATTACH] statement for an attached database.

6810 ** ^The S and M arguments passed to

6811 ** sqlite3_backup_init(D,N,S,M) identify the [database connection]

6812 ** and database name of the source database, respectively.

6813 ** ^The source and destination [database connections] (parameters S and D)

6814 ** must be different or else sqlite3_backup_init(D,N,S,M) will fail with

6815 ** an error.

6816 **

6817 ** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is

6818 ** returned and an error code and error message are stored in the

6819 ** destination [database connection] D.

6820 ** ^The error code and message for the failed call to sqlite3_backup_init()

6821 ** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or

6822 ** [sqlite3_errmsg16()] functions.

6823 ** ^A successful call to sqlite3_backup_init() returns a pointer to an

6824 ** [sqlite3_backup] object.

6825 ** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and

6826 ** sqlite3_backup_finish() functions to perform the specified backup

6827 ** operation.

6828 **

6829 ** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>

6830 **

6831 ** ^Function sqlite3_backup_step(B,N) will copy up to N pages between

6832 ** the source and destination databases specified by [sqlite3_backup] object B.

6833 ** ^If N is negative, all remaining source pages are copied.

6834 ** ^If sqlite3_backup_step(B,N) successfully copies N pages and there

6835 ** are still more pages to be copied, then the function returns [SQLITE_OK].

6836 ** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages

6837 ** from source to destination, then it returns [SQLITE_DONE].

6838 ** ^If an error occurs while running sqlite3_backup_step(B,N),

6839 ** then an [error code] is returned. ^As well as [SQLITE_OK] and

6840 ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],

6841 ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an

6842 ** [SQLITE_IOERR_ACCESS \| SQLITE_IOERR_XXX] extended error code.

6843 **

6844 ** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if

6845 ** <ol>

6846 ** <li> the destination database was opened read-only, or

6847 ** <li> the destination database is using write-ahead-log journaling

6848 ** and the destination and source page sizes differ, or

6849 ** <li> the destination database is an in-memory database and the

6850 ** destination and source page sizes differ.

6851 ** </ol>)^

6852 **

6853 ** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then

6854 ** the [sqlite3_busy_handler \| busy-handler function]

6855 ** is invoked (if one is specified). ^If the

6856 ** busy-handler returns non-zero before the lock is available, then

6857 ** [SQLITE_BUSY] is returned to the caller. ^In this case the call to

6858 ** sqlite3_backup_step() can be retried later. ^If the source

6859 ** [database connection]

6860 ** is being used to write to the source database when sqlite3_backup_step()

6861 ** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this

6862 ** case the call to sqlite3_backup_step() can be retried later on. ^(If

6863 ** [SQLITE_IOERR_ACCESS \| SQLITE_IOERR_XXX], [SQLITE_NOMEM], or

6864 ** [SQLITE_READONLY] is returned, then

6865 ** there is no point in retrying the call to sqlite3_backup_step(). These

6866 ** errors are considered fatal.)^ The application must accept

6867 ** that the backup operation has failed and pass the backup operation handle

6868 ** to the sqlite3_backup_finish() to release associated resources.

6869 **

6870 ** ^The first call to sqlite3_backup_step() obtains an exclusive lock

6871 ** on the destination file. ^The exclusive lock is not released until either

6872 ** sqlite3_backup_finish() is called or the backup operation is complete

6873 ** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to

6874 ** sqlite3_backup_step() obtains a [shared lock] on the source database that

6875 ** lasts for the duration of the sqlite3_backup_step() call.

6876 ** ^Because the source database is not locked between calls to

6877 ** sqlite3_backup_step(), the source database may be modified mid-way

6878 ** through the backup process. ^If the source database is modified by an

6879 ** external process or via a database connection other than the one being

6880 ** used by the backup operation, then the backup will be automatically

6881 ** restarted by the next call to sqlite3_backup_step(). ^If the source

6882 ** database is modified by the using the same database connection as is used

6883 ** by the backup operation, then the backup database is automatically

6884 ** updated at the same time.

6885 **

6886 ** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>

6887 **

6888 ** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the

6889 ** application wishes to abandon the backup operation, the application

6890 ** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().

6891 ** ^The sqlite3_backup_finish() interfaces releases all

6892 ** resources associated with the [sqlite3_backup] object.

6893 ** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any

6894 ** active write-transaction on the destination database is rolled back.

6895 ** The [sqlite3_backup] object is invalid

6896 ** and may not be used following a call to sqlite3_backup_finish().

6897 **

6898 ** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no

6899 ** sqlite3_backup_step() errors occurred, regardless or whether or not

6900 ** sqlite3_backup_step() completed.

6901 ** ^If an out-of-memory condition or IO error occurred during any prior

6902 ** sqlite3_backup_step() call on the same [sqlite3_backup] object, then

6903 ** sqlite3_backup_finish() returns the corresponding [error code].

6904 **

6905 ** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()

6906 ** is not a permanent error and does not affect the return value of

6907 ** sqlite3_backup_finish().

6908 **

6909 ** [[sqlite3_backup__remaining()]] [[sqlite3_backup_pagecount()]]

6910 ** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>

6911 **

6912 ** ^Each call to sqlite3_backup_step() sets two values inside

6913 ** the [sqlite3_backup] object: the number of pages still to be backed

6914 ** up and the total number of pages in the source database file.

6915 ** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces

6916 ** retrieve these two values, respectively.

6917 **

6918 ** ^The values returned by these functions are only updated by

6919 ** sqlite3_backup_step(). ^If the source database is modified during a backup

6920 ** operation, then the values are not updated to account for any extra

6921 ** pages that need to be updated or the size of the source database file

6922 ** changing.

6923 **

6924 ** <b>Concurrent Usage of Database Handles</b>

6925 **

6926 ** ^The source [database connection] may be used by the application for other

6927 ** purposes while a backup operation is underway or being initialized.

6928 ** ^If SQLite is compiled and configured to support threadsafe database

6929 ** connections, then the source database connection may be used concurrently

6930 ** from within other threads.

6931 **

6932 ** However, the application must guarantee that the destination

6933 ** [database connection] is not passed to any other API (by any thread) after

6934 ** sqlite3_backup_init() is called and before the corresponding call to

6935 ** sqlite3_backup_finish(). SQLite does not currently check to see

6936 ** if the application incorrectly accesses the destination [database connection]

6937 ** and so no error code is reported, but the operations may malfunction

6938 ** nevertheless. Use of the destination database connection while a

6939 ** backup is in progress might also also cause a mutex deadlock.

6940 **

6941 ** If running in [shared cache mode], the application must

6942 ** guarantee that the shared cache used by the destination database

6943 ** is not accessed while the backup is running. In practice this means

6944 ** that the application must guarantee that the disk file being

6945 ** backed up to is not accessed by any connection within the process,

6946 ** not just the specific connection that was passed to sqlite3_backup_init().

6947 **

6948 ** The [sqlite3_backup] object itself is partially threadsafe. Multiple

6949 ** threads may safely make multiple concurrent calls to sqlite3_backup_step().

6950 ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()

6951 ** APIs are not strictly speaking threadsafe. If they are invoked at the

6952 ** same time as another thread is invoking sqlite3_backup_step() it is

6953 ** possible that they return invalid values.

6954 */

6955 sqlite3_backup *sqlite3_backup_init(

6956 sqlite3 pDest, / Destination database handle */

6957 const char zDestName, / Destination database name */

6958 sqlite3 pSource, / Source database handle */

6959 const char zSourceName / Source database name */

6960 );

6961 int sqlite3_backup_step(sqlite3_backup *p, int nPage);

6962 int sqlite3_backup_finish(sqlite3_backup *p);

6963 int sqlite3_backup_remaining(sqlite3_backup *p);

6964 int sqlite3_backup_pagecount(sqlite3_backup *p);

6965

6966 /*

6967 ** CAPI3REF: Unlock Notification

6968 **

6969 ** ^When running in shared-cache mode, a database operation may fail with

6970 ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or

6971 ** individual tables within the shared-cache cannot be obtained. See

6972 ** [SQLite Shared-Cache Mode] for a description of shared-cache locking.

6973 ** ^This API may be used to register a callback that SQLite will invoke

6974 ** when the connection currently holding the required lock relinquishes it.

6975 ** ^This API is only available if the library was compiled with the

6976 ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.

6977 **

6978 ** See Also: [Using the SQLite Unlock Notification Feature].

6979 **

6980 ** ^Shared-cache locks are released when a database connection concludes

6981 ** its current transaction, either by committing it or rolling it back.

6982 **

6983 ** ^When a connection (known as the blocked connection) fails to obtain a

6984 ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the

6985 ** identity of the database connection (the blocking connection) that

6986 ** has locked the required resource is stored internally. ^After an

6987 ** application receives an SQLITE_LOCKED error, it may call the

6988 ** sqlite3_unlock_notify() method with the blocked connection handle as

6989 ** the first argument to register for a callback that will be invoked

6990 ** when the blocking connections current transaction is concluded. ^The

6991 ** callback is invoked from within the [sqlite3_step] or [sqlite3_close]

6992 ** call that concludes the blocking connections transaction.

6993 **

6994 ** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,

6995 ** there is a chance that the blocking connection will have already

6996 ** concluded its transaction by the time sqlite3_unlock_notify() is invoked.

6997 ** If this happens, then the specified callback is invoked immediately,

6998 ** from within the call to sqlite3_unlock_notify().)^

6999 **

7000 ** ^If the blocked connection is attempting to obtain a write-lock on a

7001 ** shared-cache table, and more than one other connection currently holds

7002 ** a read-lock on the same table, then SQLite arbitrarily selects one of

7003 ** the other connections to use as the blocking connection.

7004 **

7005 ** ^(There may be at most one unlock-notify callback registered by a

7006 ** blocked connection. If sqlite3_unlock_notify() is called when the

7007 ** blocked connection already has a registered unlock-notify callback,

7008 ** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is

7009 ** called with a NULL pointer as its second argument, then any existing

7010 ** unlock-notify callback is canceled. ^The blocked connections

7011 ** unlock-notify callback may also be canceled by closing the blocked

7012 ** connection using [sqlite3_close()].

7013 **

7014 ** The unlock-notify callback is not reentrant. If an application invokes

7015 ** any sqlite3_xxx API functions from within an unlock-notify callback, a

7016 ** crash or deadlock may be the result.

7017 **

7018 ** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always

7019 ** returns SQLITE_OK.

7020 **

7021 ** <b>Callback Invocation Details</b>

7022 **

7023 ** When an unlock-notify callback is registered, the application provides a

7024 ** single void* pointer that is passed to the callback when it is invoked.

7025 ** However, the signature of the callback function allows SQLite to pass

7026 ** it an array of void* context pointers. The first argument passed to

7027 ** an unlock-notify callback is a pointer to an array of void* pointers,

7028 ** and the second is the number of entries in the array.

7029 **

7030 ** When a blocking connections transaction is concluded, there may be

7031 ** more than one blocked connection that has registered for an unlock-notify

7032 ** callback. ^If two or more such blocked connections have specified the

7033 ** same callback function, then instead of invoking the callback function

7034 ** multiple times, it is invoked once with the set of void* context pointers

7035 ** specified by the blocked connections bundled together into an array.

7036 ** This gives the application an opportunity to prioritize any actions

7037 ** related to the set of unblocked database connections.

7038 **

7039 ** <b>Deadlock Detection</b>

7040 **

7041 ** Assuming that after registering for an unlock-notify callback a

7042 ** database waits for the callback to be issued before taking any further

7043 ** action (a reasonable assumption), then using this API may cause the

7044 ** application to deadlock. For example, if connection X is waiting for

7045 ** connection Y's transaction to be concluded, and similarly connection

7046 ** Y is waiting on connection X's transaction, then neither connection

7047 ** will proceed and the system may remain deadlocked indefinitely.

7048 **

7049 ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock

7050 ** detection. ^If a given call to sqlite3_unlock_notify() would put the

7051 ** system in a deadlocked state, then SQLITE_LOCKED is returned and no

7052 ** unlock-notify callback is registered. The system is said to be in

7053 ** a deadlocked state if connection A has registered for an unlock-notify

7054 ** callback on the conclusion of connection B's transaction, and connection

7055 ** B has itself registered for an unlock-notify callback when connection

7056 ** A's transaction is concluded. ^Indirect deadlock is also detected, so

7057 ** the system is also considered to be deadlocked if connection B has

7058 ** registered for an unlock-notify callback on the conclusion of connection

7059 ** C's transaction, where connection C is waiting on connection A. ^Any

7060 ** number of levels of indirection are allowed.

7061 **

7062 ** <b>The "DROP TABLE" Exception</b>

7063 **

7064 ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost

7065 ** always appropriate to call sqlite3_unlock_notify(). There is however,

7066 ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,

7067 ** SQLite checks if there are any currently executing SELECT statements

7068 ** that belong to the same connection. If there are, SQLITE_LOCKED is

7069 ** returned. In this case there is no "blocking connection", so invoking

7070 ** sqlite3_unlock_notify() results in the unlock-notify callback being

7071 ** invoked immediately. If the application then re-attempts the "DROP TABLE"

7072 ** or "DROP INDEX" query, an infinite loop might be the result.

7073 **

7074 ** One way around this problem is to check the extended error code returned

7075 ** by an sqlite3_step() call. ^(If there is a blocking connection, then the

7076 ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in

7077 ** the special "DROP TABLE/INDEX" case, the extended error code is just

7078 ** SQLITE_LOCKED.)^

7079 */

7080 int sqlite3_unlock_notify(

7081 sqlite3 pBlocked, / Waiting connection */

7082 void (xNotify)(void apArg, int nArg), / Callback function to invoke */

7083 void pNotifyArg / Argument to pass to xNotify */

7084 );

7085

7086

7087 /*

7088 ** CAPI3REF: String Comparison

7089 **

7090 ** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications

7091 ** and extensions to compare the contents of two buffers containing UTF-8

7092 ** strings in a case-independent fashion, using the same definition of "case

7093 ** independence" that SQLite uses internally when comparing identifiers.

7094 */

7095 int sqlite3_stricmp(const char , const char );

7096 int sqlite3_strnicmp(const char , const char , int);

7097

7098 /*

7099 ** CAPI3REF: String Globbing

7100 *

7101 ** ^The [sqlite3_strglob(P,X)] interface returns zero if string X matches

7102 ** the glob pattern P, and it returns non-zero if string X does not match

7103 ** the glob pattern P. ^The definition of glob pattern matching used in

7104 ** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the

7105 ** SQL dialect used by SQLite. ^The sqlite3_strglob(P,X) function is case

7106 ** sensitive.

7107 **

7108 ** Note that this routine returns zero on a match and non-zero if the strings

7109 ** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].

7110 */

7111 int sqlite3_strglob(const char zGlob, const char zStr);

7112

7113 /*

7114 ** CAPI3REF: Error Logging Interface

7115 **

7116 ** ^The [sqlite3_log()] interface writes a message into the [error log]

7117 ** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].

7118 ** ^If logging is enabled, the zFormat string and subsequent arguments are

7119 ** used with [sqlite3_snprintf()] to generate the final output string.

7120 **

7121 ** The sqlite3_log() interface is intended for use by extensions such as

7122 ** virtual tables, collating functions, and SQL functions. While there is

7123 ** nothing to prevent an application from calling sqlite3_log(), doing so

7124 ** is considered bad form.

7125 **

7126 ** The zFormat string must not be NULL.

7127 **

7128 ** To avoid deadlocks and other threading problems, the sqlite3_log() routine

7129 ** will not use dynamically allocated memory. The log message is stored in

7130 ** a fixed-length buffer on the stack. If the log message is longer than

7131 ** a few hundred characters, it will be truncated to the length of the

7132 ** buffer.

7133 */

7134 void sqlite3_log(int iErrCode, const char *zFormat, ...);

7135

7136 /*

7137 ** CAPI3REF: Write-Ahead Log Commit Hook

7138 **

7139 ** ^The [sqlite3_wal_hook()] function is used to register a callback that

7140 ** will be invoked each time a database connection commits data to a

7141 ** [write-ahead log] (i.e. whenever a transaction is committed in

7142 ** [journal_mode \| journal_mode=WAL mode]).

7143 **

7144 ** ^The callback is invoked by SQLite after the commit has taken place and

7145 ** the associated write-lock on the database released, so the implementation

7146 ** may read, write or [checkpoint] the database as required.

7147 **

7148 ** ^The first parameter passed to the callback function when it is invoked

7149 ** is a copy of the third parameter passed to sqlite3_wal_hook() when

7150 ** registering the callback. ^The second is a copy of the database handle.

7151 ** ^The third parameter is the name of the database that was written to -

7152 ** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter

7153 ** is the number of pages currently in the write-ahead log file,

7154 ** including those that were just committed.

7155 **

7156 ** The callback function should normally return [SQLITE_OK]. ^If an error

7157 ** code is returned, that error will propagate back up through the

7158 ** SQLite code base to cause the statement that provoked the callback

7159 ** to report an error, though the commit will have still occurred. If the

7160 ** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value

7161 ** that does not correspond to any valid SQLite error code, the results

7162 ** are undefined.

7163 **

7164 ** A single database handle may have at most a single write-ahead log callback

7165 ** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any

7166 ** previously registered write-ahead log callback. ^Note that the

7167 ** [sqlite3_wal_autocheckpoint()] interface and the

7168 ** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will

7169 ** those overwrite any prior [sqlite3_wal_hook()] settings.

7170 */

7171 void *sqlite3_wal_hook(

7172 sqlite3*,

7173 int()(void ,sqlite3,const char,int),

7174 void*

7175 );

7176

7177 /*

7178 ** CAPI3REF: Configure an auto-checkpoint

7179 **

7180 ** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around

7181 ** [sqlite3_wal_hook()] that causes any database on [database connection] D

7182 ** to automatically [checkpoint]

7183 ** after committing a transaction if there are N or

7184 ** more frames in the [write-ahead log] file. ^Passing zero or

7185 ** a negative value as the nFrame parameter disables automatic

7186 ** checkpoints entirely.

7187 **

7188 ** ^The callback registered by this function replaces any existing callback

7189 ** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback

7190 ** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism

7191 ** configured by this function.

7192 **

7193 ** ^The [wal_autocheckpoint pragma] can be used to invoke this interface

7194 ** from SQL.

7195 **

7196 ** ^Checkpoints initiated by this mechanism are

7197 ** [sqlite3_wal_checkpoint_v2\|PASSIVE].

7198 **

7199 ** ^Every new [database connection] defaults to having the auto-checkpoint

7200 ** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]

7201 ** pages. The use of this interface

7202 ** is only necessary if the default setting is found to be suboptimal

7203 ** for a particular application.

7204 */

7205 int sqlite3_wal_autocheckpoint(sqlite3 *db, int N);

7206

7207 /*

7208 ** CAPI3REF: Checkpoint a database

7209 **

7210 ** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X

7211 ** on [database connection] D to be [checkpointed]. ^If X is NULL or an

7212 ** empty string, then a checkpoint is run on all databases of

7213 ** connection D. ^If the database connection D is not in

7214 ** [WAL \| write-ahead log mode] then this interface is a harmless no-op.

7215 ** ^The [sqlite3_wal_checkpoint(D,X)] interface initiates a

7216 ** [sqlite3_wal_checkpoint_v2\|PASSIVE] checkpoint.

7217 ** Use the [sqlite3_wal_checkpoint_v2()] interface to get a FULL

7218 ** or RESET checkpoint.

7219 **

7220 ** ^The [wal_checkpoint pragma] can be used to invoke this interface

7221 ** from SQL. ^The [sqlite3_wal_autocheckpoint()] interface and the

7222 ** [wal_autocheckpoint pragma] can be used to cause this interface to be

7223 ** run whenever the WAL reaches a certain size threshold.

7224 **

7225 ** See also: [sqlite3_wal_checkpoint_v2()]

7226 */

7227 int sqlite3_wal_checkpoint(sqlite3 db, const char zDb);

7228

7229 /*

7230 ** CAPI3REF: Checkpoint a database

7231 **

7232 ** Run a checkpoint operation on WAL database zDb attached to database

7233 ** handle db. The specific operation is determined by the value of the

7234 ** eMode parameter:

7235 **

7236 ** <dl>

7237 ** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>

7238 ** Checkpoint as many frames as possible without waiting for any database

7239 ** readers or writers to finish. Sync the db file if all frames in the log

7240 ** are checkpointed. This mode is the same as calling

7241 ** sqlite3_wal_checkpoint(). The [sqlite3_busy_handler\|busy-handler callback]

7242 ** is never invoked.

7243 **

7244 ** <dt>SQLITE_CHECKPOINT_FULL<dd>

7245 ** This mode blocks (it invokes the

7246 ** [sqlite3_busy_handler\|busy-handler callback]) until there is no

7247 ** database writer and all readers are reading from the most recent database

7248 ** snapshot. It then checkpoints all frames in the log file and syncs the

7249 ** database file. This call blocks database writers while it is running,

7250 ** but not database readers.

7251 **

7252 ** <dt>SQLITE_CHECKPOINT_RESTART<dd>

7253 ** This mode works the same way as SQLITE_CHECKPOINT_FULL, except after

7254 ** checkpointing the log file it blocks (calls the

7255 ** [sqlite3_busy_handler\|busy-handler callback])

7256 ** until all readers are reading from the database file only. This ensures

7257 ** that the next client to write to the database file restarts the log file

7258 ** from the beginning. This call blocks database writers while it is running,

7259 ** but not database readers.

7260 ** </dl>

7261 **

7262 ** If pnLog is not NULL, then *pnLog is set to the total number of frames in

7263 ** the log file before returning. If pnCkpt is not NULL, then *pnCkpt is set to

7264 ** the total number of checkpointed frames (including any that were already

7265 ** checkpointed when this function is called). pnLog and pnCkpt may be

7266 ** populated even if sqlite3_wal_checkpoint_v2() returns other than SQLITE_OK.

7267 ** If no values are available because of an error, they are both set to -1

7268 ** before returning to communicate this to the caller.

7269 **

7270 ** All calls obtain an exclusive "checkpoint" lock on the database file. If

7271 ** any other process is running a checkpoint operation at the same time, the

7272 ** lock cannot be obtained and SQLITE_BUSY is returned. Even if there is a

7273 ** busy-handler configured, it will not be invoked in this case.

7274 **

7275 ** The SQLITE_CHECKPOINT_FULL and RESTART modes also obtain the exclusive

7276 ** "writer" lock on the database file. If the writer lock cannot be obtained

7277 ** immediately, and a busy-handler is configured, it is invoked and the writer

7278 ** lock retried until either the busy-handler returns 0 or the lock is

7279 ** successfully obtained. The busy-handler is also invoked while waiting for

7280 ** database readers as described above. If the busy-handler returns 0 before

7281 ** the writer lock is obtained or while waiting for database readers, the

7282 ** checkpoint operation proceeds from that point in the same way as

7283 ** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible

7284 ** without blocking any further. SQLITE_BUSY is returned in this case.

7285 **

7286 ** If parameter zDb is NULL or points to a zero length string, then the

7287 ** specified operation is attempted on all WAL databases. In this case the

7288 ** values written to output parameters pnLog and pnCkpt are undefined. If

7289 ** an SQLITE_BUSY error is encountered when processing one or more of the

7290 ** attached WAL databases, the operation is still attempted on any remaining

7291 ** attached databases and SQLITE_BUSY is returned to the caller. If any other

7292 ** error occurs while processing an attached database, processing is abandoned

7293 ** and the error code returned to the caller immediately. If no error

7294 ** (SQLITE_BUSY or otherwise) is encountered while processing the attached

7295 ** databases, SQLITE_OK is returned.

7296 **

7297 ** If database zDb is the name of an attached database that is not in WAL

7298 ** mode, SQLITE_OK is returned and both pnLog and pnCkpt set to -1. If

7299 ** zDb is not NULL (or a zero length string) and is not the name of any

7300 ** attached database, SQLITE_ERROR is returned to the caller.

7301 */

7302 int sqlite3_wal_checkpoint_v2(

7303 sqlite3 db, / Database handle */

7304 const char zDb, / Name of attached database (or NULL) */

7305 int eMode, /* SQLITE_CHECKPOINT_* value */

7306 int pnLog, / OUT: Size of WAL log in frames */

7307 int pnCkpt / OUT: Total number of frames checkpointed */

7308 );

7309

7310 /*

7311 ** CAPI3REF: Checkpoint operation parameters

7312 **

7313 ** These constants can be used as the 3rd parameter to

7314 ** [sqlite3_wal_checkpoint_v2()]. See the [sqlite3_wal_checkpoint_v2()]

7315 ** documentation for additional information about the meaning and use of

7316 ** each of these values.

7317 */

7318 #define SQLITE_CHECKPOINT_PASSIVE 0

7319 #define SQLITE_CHECKPOINT_FULL 1

7320 #define SQLITE_CHECKPOINT_RESTART 2

7321

7322 /*

7323 ** CAPI3REF: Virtual Table Interface Configuration

7324 **

7325 ** This function may be called by either the [xConnect] or [xCreate] method

7326 ** of a [virtual table] implementation to configure

7327 ** various facets of the virtual table interface.

7328 **

7329 ** If this interface is invoked outside the context of an xConnect or

7330 ** xCreate virtual table method then the behavior is undefined.

7331 **

7332 ** At present, there is only one option that may be configured using

7333 ** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options

7334 ** may be added in the future.

7335 */

7336 int sqlite3_vtab_config(sqlite3*, int op, ...);

7337

7338 /*

7339 ** CAPI3REF: Virtual Table Configuration Options

7340 **

7341 ** These macros define the various options to the

7342 ** [sqlite3_vtab_config()] interface that [virtual table] implementations

7343 ** can use to customize and optimize their behavior.

7344 **

7345 ** <dl>

7346 ** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT

7347 ** <dd>Calls of the form

7348 ** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,

7349 ** where X is an integer. If X is zero, then the [virtual table] whose

7350 ** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not

7351 ** support constraints. In this configuration (which is the default) if

7352 ** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire

7353 ** statement is rolled back as if [ON CONFLICT \| OR ABORT] had been

7354 ** specified as part of the users SQL statement, regardless of the actual

7355 ** ON CONFLICT mode specified.

7356 **

7357 ** If X is non-zero, then the virtual table implementation guarantees

7358 ** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before

7359 ** any modifications to internal or persistent data structures have been made.

7360 ** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite

7361 ** is able to roll back a statement or database transaction, and abandon

7362 ** or continue processing the current SQL statement as appropriate.

7363 ** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns

7364 ** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode

7365 ** had been ABORT.

7366 **

7367 ** Virtual table implementations that are required to handle OR REPLACE

7368 ** must do so within the [xUpdate] method. If a call to the

7369 ** [sqlite3_vtab_on_conflict()] function indicates that the current ON

7370 ** CONFLICT policy is REPLACE, the virtual table implementation should

7371 ** silently replace the appropriate rows within the xUpdate callback and

7372 ** return SQLITE_OK. Or, if this is not possible, it may return

7373 ** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT

7374 ** constraint handling.

7375 ** </dl>

7376 */

7377 #define SQLITE_VTAB_CONSTRAINT_SUPPORT 1

7378

7379 /*

7380 ** CAPI3REF: Determine The Virtual Table Conflict Policy

7381 **

7382 ** This function may only be called from within a call to the [xUpdate] method

7383 ** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The

7384 ** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],

7385 ** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode

7386 ** of the SQL statement that triggered the call to the [xUpdate] method of the

7387 ** [virtual table].

7388 */

7389 int sqlite3_vtab_on_conflict(sqlite3 *);

7390

7391 /*

7392 ** CAPI3REF: Conflict resolution modes

7393 ** KEYWORDS: {conflict resolution mode}

7394 **

7395 ** These constants are returned by [sqlite3_vtab_on_conflict()] to

7396 ** inform a [virtual table] implementation what the [ON CONFLICT] mode

7397 ** is for the SQL statement being evaluated.

7398 **

7399 ** Note that the [SQLITE_IGNORE] constant is also used as a potential

7400 ** return value from the [sqlite3_set_authorizer()] callback and that

7401 ** [SQLITE_ABORT] is also a [result code].

7402 */

7403 #define SQLITE_ROLLBACK 1

7404 /* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */

7405 #define SQLITE_FAIL 3

7406 /* #define SQLITE_ABORT 4 // Also an error code */

7407 #define SQLITE_REPLACE 5

7408

7409

7410

7411 /*

7412 ** Undo the hack that converts floating point types to integer for

7413 ** builds on processors without floating point support.

7414 */

7415 #ifdef SQLITE_OMIT_FLOATING_POINT

7416 # undef double

7417 #endif

7418

7419 #ifdef __cplusplus

7420 } /* End of the 'extern "C"' block */

7421 #endif

7422 #endif /* _SQLITE3_H_ */

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