sqlite3.h 327 KB

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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. ** Make sure we can call this stuff from C++.
  38. */
  39. #ifdef __cplusplus
  40. extern "C" {
  41. #endif
  42. /*
  43. ** Add the ability to override 'extern'
  44. */
  45. #ifndef SQLITE_EXTERN
  46. # define SQLITE_EXTERN extern
  47. #endif
  48. #ifndef SQLITE_API
  49. # define SQLITE_API
  50. #endif
  51. /*
  52. ** These no-op macros are used in front of interfaces to mark those
  53. ** interfaces as either deprecated or experimental. New applications
  54. ** should not use deprecated interfaces - they are support for backwards
  55. ** compatibility only. Application writers should be aware that
  56. ** experimental interfaces are subject to change in point releases.
  57. **
  58. ** These macros used to resolve to various kinds of compiler magic that
  59. ** would generate warning messages when they were used. But that
  60. ** compiler magic ended up generating such a flurry of bug reports
  61. ** that we have taken it all out and gone back to using simple
  62. ** noop macros.
  63. */
  64. #define SQLITE_DEPRECATED
  65. #define SQLITE_EXPERIMENTAL
  66. /*
  67. ** Ensure these symbols were not defined by some previous header file.
  68. */
  69. #ifdef SQLITE_VERSION
  70. # undef SQLITE_VERSION
  71. #endif
  72. #ifdef SQLITE_VERSION_NUMBER
  73. # undef SQLITE_VERSION_NUMBER
  74. #endif
  75. /*
  76. ** CAPI3REF: Compile-Time Library Version Numbers
  77. **
  78. ** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header
  79. ** evaluates to a string literal that is the SQLite version in the
  80. ** format "X.Y.Z" where X is the major version number (always 3 for
  81. ** SQLite3) and Y is the minor version number and Z is the release number.)^
  82. ** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer
  83. ** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same
  84. ** numbers used in [SQLITE_VERSION].)^
  85. ** The SQLITE_VERSION_NUMBER for any given release of SQLite will also
  86. ** be larger than the release from which it is derived. Either Y will
  87. ** be held constant and Z will be incremented or else Y will be incremented
  88. ** and Z will be reset to zero.
  89. **
  90. ** Since version 3.6.18, SQLite source code has been stored in the
  91. ** <a href="http://www.fossil-scm.org/">Fossil configuration management
  92. ** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to
  93. ** a string which identifies a particular check-in of SQLite
  94. ** within its configuration management system. ^The SQLITE_SOURCE_ID
  95. ** string contains the date and time of the check-in (UTC) and an SHA1
  96. ** hash of the entire source tree.
  97. **
  98. ** See also: [sqlite3_libversion()],
  99. ** [sqlite3_libversion_number()], [sqlite3_sourceid()],
  100. ** [sqlite_version()] and [sqlite_source_id()].
  101. */
  102. #define SQLITE_VERSION "3.7.11"
  103. #define SQLITE_VERSION_NUMBER 3007011
  104. #define SQLITE_SOURCE_ID "2012-03-20 11:35:50 00bb9c9ce4f465e6ac321ced2a9d0062dc364669"
  105. /*
  106. ** CAPI3REF: Run-Time Library Version Numbers
  107. ** KEYWORDS: sqlite3_version, sqlite3_sourceid
  108. **
  109. ** These interfaces provide the same information as the [SQLITE_VERSION],
  110. ** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros
  111. ** but are associated with the library instead of the header file. ^(Cautious
  112. ** programmers might include assert() statements in their application to
  113. ** verify that values returned by these interfaces match the macros in
  114. ** the header, and thus insure that the application is
  115. ** compiled with matching library and header files.
  116. **
  117. ** <blockquote><pre>
  118. ** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
  119. ** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 );
  120. ** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
  121. ** </pre></blockquote>)^
  122. **
  123. ** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION]
  124. ** macro. ^The sqlite3_libversion() function returns a pointer to the
  125. ** to the sqlite3_version[] string constant. The sqlite3_libversion()
  126. ** function is provided for use in DLLs since DLL users usually do not have
  127. ** direct access to string constants within the DLL. ^The
  128. ** sqlite3_libversion_number() function returns an integer equal to
  129. ** [SQLITE_VERSION_NUMBER]. ^The sqlite3_sourceid() function returns
  130. ** a pointer to a string constant whose value is the same as the
  131. ** [SQLITE_SOURCE_ID] C preprocessor macro.
  132. **
  133. ** See also: [sqlite_version()] and [sqlite_source_id()].
  134. */
  135. SQLITE_API SQLITE_EXTERN const char sqlite3_version[];
  136. SQLITE_API const char *sqlite3_libversion(void);
  137. SQLITE_API const char *sqlite3_sourceid(void);
  138. SQLITE_API int sqlite3_libversion_number(void);
  139. /*
  140. ** CAPI3REF: Run-Time Library Compilation Options Diagnostics
  141. **
  142. ** ^The sqlite3_compileoption_used() function returns 0 or 1
  143. ** indicating whether the specified option was defined at
  144. ** compile time. ^The SQLITE_ prefix may be omitted from the
  145. ** option name passed to sqlite3_compileoption_used().
  146. **
  147. ** ^The sqlite3_compileoption_get() function allows iterating
  148. ** over the list of options that were defined at compile time by
  149. ** returning the N-th compile time option string. ^If N is out of range,
  150. ** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_
  151. ** prefix is omitted from any strings returned by
  152. ** sqlite3_compileoption_get().
  153. **
  154. ** ^Support for the diagnostic functions sqlite3_compileoption_used()
  155. ** and sqlite3_compileoption_get() may be omitted by specifying the
  156. ** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time.
  157. **
  158. ** See also: SQL functions [sqlite_compileoption_used()] and
  159. ** [sqlite_compileoption_get()] and the [compile_options pragma].
  160. */
  161. #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
  162. SQLITE_API int sqlite3_compileoption_used(const char *zOptName);
  163. SQLITE_API const char *sqlite3_compileoption_get(int N);
  164. #endif
  165. /*
  166. ** CAPI3REF: Test To See If The Library Is Threadsafe
  167. **
  168. ** ^The sqlite3_threadsafe() function returns zero if and only if
  169. ** SQLite was compiled with mutexing code omitted due to the
  170. ** [SQLITE_THREADSAFE] compile-time option being set to 0.
  171. **
  172. ** SQLite can be compiled with or without mutexes. When
  173. ** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
  174. ** are enabled and SQLite is threadsafe. When the
  175. ** [SQLITE_THREADSAFE] macro is 0,
  176. ** the mutexes are omitted. Without the mutexes, it is not safe
  177. ** to use SQLite concurrently from more than one thread.
  178. **
  179. ** Enabling mutexes incurs a measurable performance penalty.
  180. ** So if speed is of utmost importance, it makes sense to disable
  181. ** the mutexes. But for maximum safety, mutexes should be enabled.
  182. ** ^The default behavior is for mutexes to be enabled.
  183. **
  184. ** This interface can be used by an application to make sure that the
  185. ** version of SQLite that it is linking against was compiled with
  186. ** the desired setting of the [SQLITE_THREADSAFE] macro.
  187. **
  188. ** This interface only reports on the compile-time mutex setting
  189. ** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with
  190. ** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
  191. ** can be fully or partially disabled using a call to [sqlite3_config()]
  192. ** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD],
  193. ** or [SQLITE_CONFIG_MUTEX]. ^(The return value of the
  194. ** sqlite3_threadsafe() function shows only the compile-time setting of
  195. ** thread safety, not any run-time changes to that setting made by
  196. ** sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
  197. ** is unchanged by calls to sqlite3_config().)^
  198. **
  199. ** See the [threading mode] documentation for additional information.
  200. */
  201. SQLITE_API int sqlite3_threadsafe(void);
  202. /*
  203. ** CAPI3REF: Database Connection Handle
  204. ** KEYWORDS: {database connection} {database connections}
  205. **
  206. ** Each open SQLite database is represented by a pointer to an instance of
  207. ** the opaque structure named "sqlite3". It is useful to think of an sqlite3
  208. ** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and
  209. ** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
  210. ** is its destructor. There are many other interfaces (such as
  211. ** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
  212. ** [sqlite3_busy_timeout()] to name but three) that are methods on an
  213. ** sqlite3 object.
  214. */
  215. typedef struct sqlite3 sqlite3;
  216. /*
  217. ** CAPI3REF: 64-Bit Integer Types
  218. ** KEYWORDS: sqlite_int64 sqlite_uint64
  219. **
  220. ** Because there is no cross-platform way to specify 64-bit integer types
  221. ** SQLite includes typedefs for 64-bit signed and unsigned integers.
  222. **
  223. ** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
  224. ** The sqlite_int64 and sqlite_uint64 types are supported for backwards
  225. ** compatibility only.
  226. **
  227. ** ^The sqlite3_int64 and sqlite_int64 types can store integer values
  228. ** between -9223372036854775808 and +9223372036854775807 inclusive. ^The
  229. ** sqlite3_uint64 and sqlite_uint64 types can store integer values
  230. ** between 0 and +18446744073709551615 inclusive.
  231. */
  232. #ifdef SQLITE_INT64_TYPE
  233. typedef SQLITE_INT64_TYPE sqlite_int64;
  234. typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
  235. #elif defined(_MSC_VER) || defined(__BORLANDC__)
  236. typedef __int64 sqlite_int64;
  237. typedef unsigned __int64 sqlite_uint64;
  238. #else
  239. typedef long long int sqlite_int64;
  240. typedef unsigned long long int sqlite_uint64;
  241. #endif
  242. typedef sqlite_int64 sqlite3_int64;
  243. typedef sqlite_uint64 sqlite3_uint64;
  244. /*
  245. ** If compiling for a processor that lacks floating point support,
  246. ** substitute integer for floating-point.
  247. */
  248. #ifdef SQLITE_OMIT_FLOATING_POINT
  249. # define double sqlite3_int64
  250. #endif
  251. /*
  252. ** CAPI3REF: Closing A Database Connection
  253. **
  254. ** ^The sqlite3_close() routine is the destructor for the [sqlite3] object.
  255. ** ^Calls to sqlite3_close() return SQLITE_OK if the [sqlite3] object is
  256. ** successfully destroyed and all associated resources are deallocated.
  257. **
  258. ** Applications must [sqlite3_finalize | finalize] all [prepared statements]
  259. ** and [sqlite3_blob_close | close] all [BLOB handles] associated with
  260. ** the [sqlite3] object prior to attempting to close the object. ^If
  261. ** sqlite3_close() is called on a [database connection] that still has
  262. ** outstanding [prepared statements] or [BLOB handles], then it returns
  263. ** SQLITE_BUSY.
  264. **
  265. ** ^If [sqlite3_close()] is invoked while a transaction is open,
  266. ** the transaction is automatically rolled back.
  267. **
  268. ** The C parameter to [sqlite3_close(C)] must be either a NULL
  269. ** pointer or an [sqlite3] object pointer obtained
  270. ** from [sqlite3_open()], [sqlite3_open16()], or
  271. ** [sqlite3_open_v2()], and not previously closed.
  272. ** ^Calling sqlite3_close() with a NULL pointer argument is a
  273. ** harmless no-op.
  274. */
  275. SQLITE_API int sqlite3_close(sqlite3 *);
  276. /*
  277. ** The type for a callback function.
  278. ** This is legacy and deprecated. It is included for historical
  279. ** compatibility and is not documented.
  280. */
  281. typedef int (*sqlite3_callback)(void*,int,char**, char**);
  282. /*
  283. ** CAPI3REF: One-Step Query Execution Interface
  284. **
  285. ** The sqlite3_exec() interface is a convenience wrapper around
  286. ** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
  287. ** that allows an application to run multiple statements of SQL
  288. ** without having to use a lot of C code.
  289. **
  290. ** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
  291. ** semicolon-separate SQL statements passed into its 2nd argument,
  292. ** in the context of the [database connection] passed in as its 1st
  293. ** argument. ^If the callback function of the 3rd argument to
  294. ** sqlite3_exec() is not NULL, then it is invoked for each result row
  295. ** coming out of the evaluated SQL statements. ^The 4th argument to
  296. ** sqlite3_exec() is relayed through to the 1st argument of each
  297. ** callback invocation. ^If the callback pointer to sqlite3_exec()
  298. ** is NULL, then no callback is ever invoked and result rows are
  299. ** ignored.
  300. **
  301. ** ^If an error occurs while evaluating the SQL statements passed into
  302. ** sqlite3_exec(), then execution of the current statement stops and
  303. ** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec()
  304. ** is not NULL then any error message is written into memory obtained
  305. ** from [sqlite3_malloc()] and passed back through the 5th parameter.
  306. ** To avoid memory leaks, the application should invoke [sqlite3_free()]
  307. ** on error message strings returned through the 5th parameter of
  308. ** of sqlite3_exec() after the error message string is no longer needed.
  309. ** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
  310. ** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
  311. ** NULL before returning.
  312. **
  313. ** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
  314. ** routine returns SQLITE_ABORT without invoking the callback again and
  315. ** without running any subsequent SQL statements.
  316. **
  317. ** ^The 2nd argument to the sqlite3_exec() callback function is the
  318. ** number of columns in the result. ^The 3rd argument to the sqlite3_exec()
  319. ** callback is an array of pointers to strings obtained as if from
  320. ** [sqlite3_column_text()], one for each column. ^If an element of a
  321. ** result row is NULL then the corresponding string pointer for the
  322. ** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the
  323. ** sqlite3_exec() callback is an array of pointers to strings where each
  324. ** entry represents the name of corresponding result column as obtained
  325. ** from [sqlite3_column_name()].
  326. **
  327. ** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
  328. ** to an empty string, or a pointer that contains only whitespace and/or
  329. ** SQL comments, then no SQL statements are evaluated and the database
  330. ** is not changed.
  331. **
  332. ** Restrictions:
  333. **
  334. ** <ul>
  335. ** <li> The application must insure that the 1st parameter to sqlite3_exec()
  336. ** is a valid and open [database connection].
  337. ** <li> The application must not close [database connection] specified by
  338. ** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
  339. ** <li> The application must not modify the SQL statement text passed into
  340. ** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
  341. ** </ul>
  342. */
  343. SQLITE_API int sqlite3_exec(
  344. sqlite3*, /* An open database */
  345. const char *sql, /* SQL to be evaluated */
  346. int (*callback)(void*,int,char**,char**), /* Callback function */
  347. void *, /* 1st argument to callback */
  348. char **errmsg /* Error msg written here */
  349. );
  350. /*
  351. ** CAPI3REF: Result Codes
  352. ** KEYWORDS: SQLITE_OK {error code} {error codes}
  353. ** KEYWORDS: {result code} {result codes}
  354. **
  355. ** Many SQLite functions return an integer result code from the set shown
  356. ** here in order to indicate success or failure.
  357. **
  358. ** New error codes may be added in future versions of SQLite.
  359. **
  360. ** See also: [SQLITE_IOERR_READ | extended result codes],
  361. ** [sqlite3_vtab_on_conflict()] [SQLITE_ROLLBACK | result codes].
  362. */
  363. #define SQLITE_OK 0 /* Successful result */
  364. /* beginning-of-error-codes */
  365. #define SQLITE_ERROR 1 /* SQL error or missing database */
  366. #define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */
  367. #define SQLITE_PERM 3 /* Access permission denied */
  368. #define SQLITE_ABORT 4 /* Callback routine requested an abort */
  369. #define SQLITE_BUSY 5 /* The database file is locked */
  370. #define SQLITE_LOCKED 6 /* A table in the database is locked */
  371. #define SQLITE_NOMEM 7 /* A malloc() failed */
  372. #define SQLITE_READONLY 8 /* Attempt to write a readonly database */
  373. #define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/
  374. #define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */
  375. #define SQLITE_CORRUPT 11 /* The database disk image is malformed */
  376. #define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */
  377. #define SQLITE_FULL 13 /* Insertion failed because database is full */
  378. #define SQLITE_CANTOPEN 14 /* Unable to open the database file */
  379. #define SQLITE_PROTOCOL 15 /* Database lock protocol error */
  380. #define SQLITE_EMPTY 16 /* Database is empty */
  381. #define SQLITE_SCHEMA 17 /* The database schema changed */
  382. #define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */
  383. #define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */
  384. #define SQLITE_MISMATCH 20 /* Data type mismatch */
  385. #define SQLITE_MISUSE 21 /* Library used incorrectly */
  386. #define SQLITE_NOLFS 22 /* Uses OS features not supported on host */
  387. #define SQLITE_AUTH 23 /* Authorization denied */
  388. #define SQLITE_FORMAT 24 /* Auxiliary database format error */
  389. #define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */
  390. #define SQLITE_NOTADB 26 /* File opened that is not a database file */
  391. #define SQLITE_ROW 100 /* sqlite3_step() has another row ready */
  392. #define SQLITE_DONE 101 /* sqlite3_step() has finished executing */
  393. /* end-of-error-codes */
  394. /*
  395. ** CAPI3REF: Extended Result Codes
  396. ** KEYWORDS: {extended error code} {extended error codes}
  397. ** KEYWORDS: {extended result code} {extended result codes}
  398. **
  399. ** In its default configuration, SQLite API routines return one of 26 integer
  400. ** [SQLITE_OK | result codes]. However, experience has shown that many of
  401. ** these result codes are too coarse-grained. They do not provide as
  402. ** much information about problems as programmers might like. In an effort to
  403. ** address this, newer versions of SQLite (version 3.3.8 and later) include
  404. ** support for additional result codes that provide more detailed information
  405. ** about errors. The extended result codes are enabled or disabled
  406. ** on a per database connection basis using the
  407. ** [sqlite3_extended_result_codes()] API.
  408. **
  409. ** Some of the available extended result codes are listed here.
  410. ** One may expect the number of extended result codes will be expand
  411. ** over time. Software that uses extended result codes should expect
  412. ** to see new result codes in future releases of SQLite.
  413. **
  414. ** The SQLITE_OK result code will never be extended. It will always
  415. ** be exactly zero.
  416. */
  417. #define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8))
  418. #define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8))
  419. #define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8))
  420. #define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8))
  421. #define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8))
  422. #define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8))
  423. #define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8))
  424. #define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8))
  425. #define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8))
  426. #define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8))
  427. #define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8))
  428. #define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8))
  429. #define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8))
  430. #define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
  431. #define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8))
  432. #define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8))
  433. #define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8))
  434. #define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8))
  435. #define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8))
  436. #define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8))
  437. #define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8))
  438. #define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8))
  439. #define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8))
  440. #define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8))
  441. #define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8))
  442. #define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8))
  443. #define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8))
  444. #define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8))
  445. #define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8))
  446. /*
  447. ** CAPI3REF: Flags For File Open Operations
  448. **
  449. ** These bit values are intended for use in the
  450. ** 3rd parameter to the [sqlite3_open_v2()] interface and
  451. ** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
  452. */
  453. #define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */
  454. #define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */
  455. #define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */
  456. #define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */
  457. #define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */
  458. #define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */
  459. #define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */
  460. #define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */
  461. #define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */
  462. #define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */
  463. #define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */
  464. #define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */
  465. #define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */
  466. #define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */
  467. #define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */
  468. #define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */
  469. #define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */
  470. #define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */
  471. #define SQLITE_OPEN_WAL 0x00080000 /* VFS only */
  472. /* Reserved: 0x00F00000 */
  473. /*
  474. ** CAPI3REF: Device Characteristics
  475. **
  476. ** The xDeviceCharacteristics method of the [sqlite3_io_methods]
  477. ** object returns an integer which is a vector of the these
  478. ** bit values expressing I/O characteristics of the mass storage
  479. ** device that holds the file that the [sqlite3_io_methods]
  480. ** refers to.
  481. **
  482. ** The SQLITE_IOCAP_ATOMIC property means that all writes of
  483. ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
  484. ** mean that writes of blocks that are nnn bytes in size and
  485. ** are aligned to an address which is an integer multiple of
  486. ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
  487. ** that when data is appended to a file, the data is appended
  488. ** first then the size of the file is extended, never the other
  489. ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
  490. ** information is written to disk in the same order as calls
  491. ** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
  492. ** after reboot following a crash or power loss, the only bytes in a
  493. ** file that were written at the application level might have changed
  494. ** and that adjacent bytes, even bytes within the same sector are
  495. ** guaranteed to be unchanged.
  496. */
  497. #define SQLITE_IOCAP_ATOMIC 0x00000001
  498. #define SQLITE_IOCAP_ATOMIC512 0x00000002
  499. #define SQLITE_IOCAP_ATOMIC1K 0x00000004
  500. #define SQLITE_IOCAP_ATOMIC2K 0x00000008
  501. #define SQLITE_IOCAP_ATOMIC4K 0x00000010
  502. #define SQLITE_IOCAP_ATOMIC8K 0x00000020
  503. #define SQLITE_IOCAP_ATOMIC16K 0x00000040
  504. #define SQLITE_IOCAP_ATOMIC32K 0x00000080
  505. #define SQLITE_IOCAP_ATOMIC64K 0x00000100
  506. #define SQLITE_IOCAP_SAFE_APPEND 0x00000200
  507. #define SQLITE_IOCAP_SEQUENTIAL 0x00000400
  508. #define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800
  509. #define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000
  510. /*
  511. ** CAPI3REF: File Locking Levels
  512. **
  513. ** SQLite uses one of these integer values as the second
  514. ** argument to calls it makes to the xLock() and xUnlock() methods
  515. ** of an [sqlite3_io_methods] object.
  516. */
  517. #define SQLITE_LOCK_NONE 0
  518. #define SQLITE_LOCK_SHARED 1
  519. #define SQLITE_LOCK_RESERVED 2
  520. #define SQLITE_LOCK_PENDING 3
  521. #define SQLITE_LOCK_EXCLUSIVE 4
  522. /*
  523. ** CAPI3REF: Synchronization Type Flags
  524. **
  525. ** When SQLite invokes the xSync() method of an
  526. ** [sqlite3_io_methods] object it uses a combination of
  527. ** these integer values as the second argument.
  528. **
  529. ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
  530. ** sync operation only needs to flush data to mass storage. Inode
  531. ** information need not be flushed. If the lower four bits of the flag
  532. ** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
  533. ** If the lower four bits equal SQLITE_SYNC_FULL, that means
  534. ** to use Mac OS X style fullsync instead of fsync().
  535. **
  536. ** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
  537. ** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
  538. ** settings. The [synchronous pragma] determines when calls to the
  539. ** xSync VFS method occur and applies uniformly across all platforms.
  540. ** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
  541. ** energetic or rigorous or forceful the sync operations are and
  542. ** only make a difference on Mac OSX for the default SQLite code.
  543. ** (Third-party VFS implementations might also make the distinction
  544. ** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
  545. ** operating systems natively supported by SQLite, only Mac OSX
  546. ** cares about the difference.)
  547. */
  548. #define SQLITE_SYNC_NORMAL 0x00002
  549. #define SQLITE_SYNC_FULL 0x00003
  550. #define SQLITE_SYNC_DATAONLY 0x00010
  551. /*
  552. ** CAPI3REF: OS Interface Open File Handle
  553. **
  554. ** An [sqlite3_file] object represents an open file in the
  555. ** [sqlite3_vfs | OS interface layer]. Individual OS interface
  556. ** implementations will
  557. ** want to subclass this object by appending additional fields
  558. ** for their own use. The pMethods entry is a pointer to an
  559. ** [sqlite3_io_methods] object that defines methods for performing
  560. ** I/O operations on the open file.
  561. */
  562. typedef struct sqlite3_file sqlite3_file;
  563. struct sqlite3_file {
  564. const struct sqlite3_io_methods *pMethods; /* Methods for an open file */
  565. };
  566. /*
  567. ** CAPI3REF: OS Interface File Virtual Methods Object
  568. **
  569. ** Every file opened by the [sqlite3_vfs.xOpen] method populates an
  570. ** [sqlite3_file] object (or, more commonly, a subclass of the
  571. ** [sqlite3_file] object) with a pointer to an instance of this object.
  572. ** This object defines the methods used to perform various operations
  573. ** against the open file represented by the [sqlite3_file] object.
  574. **
  575. ** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element
  576. ** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
  577. ** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The
  578. ** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
  579. ** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
  580. ** to NULL.
  581. **
  582. ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
  583. ** [SQLITE_SYNC_FULL]. The first choice is the normal fsync().
  584. ** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY]
  585. ** flag may be ORed in to indicate that only the data of the file
  586. ** and not its inode needs to be synced.
  587. **
  588. ** The integer values to xLock() and xUnlock() are one of
  589. ** <ul>
  590. ** <li> [SQLITE_LOCK_NONE],
  591. ** <li> [SQLITE_LOCK_SHARED],
  592. ** <li> [SQLITE_LOCK_RESERVED],
  593. ** <li> [SQLITE_LOCK_PENDING], or
  594. ** <li> [SQLITE_LOCK_EXCLUSIVE].
  595. ** </ul>
  596. ** xLock() increases the lock. xUnlock() decreases the lock.
  597. ** The xCheckReservedLock() method checks whether any database connection,
  598. ** either in this process or in some other process, is holding a RESERVED,
  599. ** PENDING, or EXCLUSIVE lock on the file. It returns true
  600. ** if such a lock exists and false otherwise.
  601. **
  602. ** The xFileControl() method is a generic interface that allows custom
  603. ** VFS implementations to directly control an open file using the
  604. ** [sqlite3_file_control()] interface. The second "op" argument is an
  605. ** integer opcode. The third argument is a generic pointer intended to
  606. ** point to a structure that may contain arguments or space in which to
  607. ** write return values. Potential uses for xFileControl() might be
  608. ** functions to enable blocking locks with timeouts, to change the
  609. ** locking strategy (for example to use dot-file locks), to inquire
  610. ** about the status of a lock, or to break stale locks. The SQLite
  611. ** core reserves all opcodes less than 100 for its own use.
  612. ** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available.
  613. ** Applications that define a custom xFileControl method should use opcodes
  614. ** greater than 100 to avoid conflicts. VFS implementations should
  615. ** return [SQLITE_NOTFOUND] for file control opcodes that they do not
  616. ** recognize.
  617. **
  618. ** The xSectorSize() method returns the sector size of the
  619. ** device that underlies the file. The sector size is the
  620. ** minimum write that can be performed without disturbing
  621. ** other bytes in the file. The xDeviceCharacteristics()
  622. ** method returns a bit vector describing behaviors of the
  623. ** underlying device:
  624. **
  625. ** <ul>
  626. ** <li> [SQLITE_IOCAP_ATOMIC]
  627. ** <li> [SQLITE_IOCAP_ATOMIC512]
  628. ** <li> [SQLITE_IOCAP_ATOMIC1K]
  629. ** <li> [SQLITE_IOCAP_ATOMIC2K]
  630. ** <li> [SQLITE_IOCAP_ATOMIC4K]
  631. ** <li> [SQLITE_IOCAP_ATOMIC8K]
  632. ** <li> [SQLITE_IOCAP_ATOMIC16K]
  633. ** <li> [SQLITE_IOCAP_ATOMIC32K]
  634. ** <li> [SQLITE_IOCAP_ATOMIC64K]
  635. ** <li> [SQLITE_IOCAP_SAFE_APPEND]
  636. ** <li> [SQLITE_IOCAP_SEQUENTIAL]
  637. ** </ul>
  638. **
  639. ** The SQLITE_IOCAP_ATOMIC property means that all writes of
  640. ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
  641. ** mean that writes of blocks that are nnn bytes in size and
  642. ** are aligned to an address which is an integer multiple of
  643. ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
  644. ** that when data is appended to a file, the data is appended
  645. ** first then the size of the file is extended, never the other
  646. ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
  647. ** information is written to disk in the same order as calls
  648. ** to xWrite().
  649. **
  650. ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
  651. ** in the unread portions of the buffer with zeros. A VFS that
  652. ** fails to zero-fill short reads might seem to work. However,
  653. ** failure to zero-fill short reads will eventually lead to
  654. ** database corruption.
  655. */
  656. typedef struct sqlite3_io_methods sqlite3_io_methods;
  657. struct sqlite3_io_methods {
  658. int iVersion;
  659. int (*xClose)(sqlite3_file*);
  660. int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
  661. int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
  662. int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
  663. int (*xSync)(sqlite3_file*, int flags);
  664. int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
  665. int (*xLock)(sqlite3_file*, int);
  666. int (*xUnlock)(sqlite3_file*, int);
  667. int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
  668. int (*xFileControl)(sqlite3_file*, int op, void *pArg);
  669. int (*xSectorSize)(sqlite3_file*);
  670. int (*xDeviceCharacteristics)(sqlite3_file*);
  671. /* Methods above are valid for version 1 */
  672. int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
  673. int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
  674. void (*xShmBarrier)(sqlite3_file*);
  675. int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
  676. /* Methods above are valid for version 2 */
  677. /* Additional methods may be added in future releases */
  678. };
  679. /*
  680. ** CAPI3REF: Standard File Control Opcodes
  681. **
  682. ** These integer constants are opcodes for the xFileControl method
  683. ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
  684. ** interface.
  685. **
  686. ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This
  687. ** opcode causes the xFileControl method to write the current state of
  688. ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
  689. ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
  690. ** into an integer that the pArg argument points to. This capability
  691. ** is used during testing and only needs to be supported when SQLITE_TEST
  692. ** is defined.
  693. ** <ul>
  694. ** <li>[[SQLITE_FCNTL_SIZE_HINT]]
  695. ** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
  696. ** layer a hint of how large the database file will grow to be during the
  697. ** current transaction. This hint is not guaranteed to be accurate but it
  698. ** is often close. The underlying VFS might choose to preallocate database
  699. ** file space based on this hint in order to help writes to the database
  700. ** file run faster.
  701. **
  702. ** <li>[[SQLITE_FCNTL_CHUNK_SIZE]]
  703. ** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
  704. ** extends and truncates the database file in chunks of a size specified
  705. ** by the user. The fourth argument to [sqlite3_file_control()] should
  706. ** point to an integer (type int) containing the new chunk-size to use
  707. ** for the nominated database. Allocating database file space in large
  708. ** chunks (say 1MB at a time), may reduce file-system fragmentation and
  709. ** improve performance on some systems.
  710. **
  711. ** <li>[[SQLITE_FCNTL_FILE_POINTER]]
  712. ** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
  713. ** to the [sqlite3_file] object associated with a particular database
  714. ** connection. See the [sqlite3_file_control()] documentation for
  715. ** additional information.
  716. **
  717. ** <li>[[SQLITE_FCNTL_SYNC_OMITTED]]
  718. ** ^(The [SQLITE_FCNTL_SYNC_OMITTED] opcode is generated internally by
  719. ** SQLite and sent to all VFSes in place of a call to the xSync method
  720. ** when the database connection has [PRAGMA synchronous] set to OFF.)^
  721. ** Some specialized VFSes need this signal in order to operate correctly
  722. ** when [PRAGMA synchronous | PRAGMA synchronous=OFF] is set, but most
  723. ** VFSes do not need this signal and should silently ignore this opcode.
  724. ** Applications should not call [sqlite3_file_control()] with this
  725. ** opcode as doing so may disrupt the operation of the specialized VFSes
  726. ** that do require it.
  727. **
  728. ** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]]
  729. ** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
  730. ** retry counts and intervals for certain disk I/O operations for the
  731. ** windows [VFS] in order to provide robustness in the presence of
  732. ** anti-virus programs. By default, the windows VFS will retry file read,
  733. ** file write, and file delete operations up to 10 times, with a delay
  734. ** of 25 milliseconds before the first retry and with the delay increasing
  735. ** by an additional 25 milliseconds with each subsequent retry. This
  736. ** opcode allows these two values (10 retries and 25 milliseconds of delay)
  737. ** to be adjusted. The values are changed for all database connections
  738. ** within the same process. The argument is a pointer to an array of two
  739. ** integers where the first integer i the new retry count and the second
  740. ** integer is the delay. If either integer is negative, then the setting
  741. ** is not changed but instead the prior value of that setting is written
  742. ** into the array entry, allowing the current retry settings to be
  743. ** interrogated. The zDbName parameter is ignored.
  744. **
  745. ** <li>[[SQLITE_FCNTL_PERSIST_WAL]]
  746. ** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
  747. ** persistent [WAL | Write AHead Log] setting. By default, the auxiliary
  748. ** write ahead log and shared memory files used for transaction control
  749. ** are automatically deleted when the latest connection to the database
  750. ** closes. Setting persistent WAL mode causes those files to persist after
  751. ** close. Persisting the files is useful when other processes that do not
  752. ** have write permission on the directory containing the database file want
  753. ** to read the database file, as the WAL and shared memory files must exist
  754. ** in order for the database to be readable. The fourth parameter to
  755. ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
  756. ** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
  757. ** WAL mode. If the integer is -1, then it is overwritten with the current
  758. ** WAL persistence setting.
  759. **
  760. ** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]]
  761. ** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
  762. ** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting
  763. ** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
  764. ** xDeviceCharacteristics methods. The fourth parameter to
  765. ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
  766. ** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
  767. ** mode. If the integer is -1, then it is overwritten with the current
  768. ** zero-damage mode setting.
  769. **
  770. ** <li>[[SQLITE_FCNTL_OVERWRITE]]
  771. ** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
  772. ** a write transaction to indicate that, unless it is rolled back for some
  773. ** reason, the entire database file will be overwritten by the current
  774. ** transaction. This is used by VACUUM operations.
  775. **
  776. ** <li>[[SQLITE_FCNTL_VFSNAME]]
  777. ** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
  778. ** all [VFSes] in the VFS stack. The names are of all VFS shims and the
  779. ** final bottom-level VFS are written into memory obtained from
  780. ** [sqlite3_malloc()] and the result is stored in the char* variable
  781. ** that the fourth parameter of [sqlite3_file_control()] points to.
  782. ** The caller is responsible for freeing the memory when done. As with
  783. ** all file-control actions, there is no guarantee that this will actually
  784. ** do anything. Callers should initialize the char* variable to a NULL
  785. ** pointer in case this file-control is not implemented. This file-control
  786. ** is intended for diagnostic use only.
  787. **
  788. ** <li>[[SQLITE_FCNTL_PRAGMA]]
  789. ** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA]
  790. ** file control is sent to the open [sqlite3_file] object corresponding
  791. ** to the database file to which the pragma statement refers. ^The argument
  792. ** to the [SQLITE_FCNTL_PRAGMA] file control is an array of
  793. ** pointers to strings (char**) in which the second element of the array
  794. ** is the name of the pragma and the third element is the argument to the
  795. ** pragma or NULL if the pragma has no argument. ^The handler for an
  796. ** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element
  797. ** of the char** argument point to a string obtained from [sqlite3_mprintf()]
  798. ** or the equivalent and that string will become the result of the pragma or
  799. ** the error message if the pragma fails. ^If the
  800. ** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal
  801. ** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA]
  802. ** file control returns [SQLITE_OK], then the parser assumes that the
  803. ** VFS has handled the PRAGMA itself and the parser generates a no-op
  804. ** prepared statement. ^If the [SQLITE_FCNTL_PRAGMA] file control returns
  805. ** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means
  806. ** that the VFS encountered an error while handling the [PRAGMA] and the
  807. ** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA]
  808. ** file control occurs at the beginning of pragma statement analysis and so
  809. ** it is able to override built-in [PRAGMA] statements.
  810. ** </ul>
  811. */
  812. #define SQLITE_FCNTL_LOCKSTATE 1
  813. #define SQLITE_GET_LOCKPROXYFILE 2
  814. #define SQLITE_SET_LOCKPROXYFILE 3
  815. #define SQLITE_LAST_ERRNO 4
  816. #define SQLITE_FCNTL_SIZE_HINT 5
  817. #define SQLITE_FCNTL_CHUNK_SIZE 6
  818. #define SQLITE_FCNTL_FILE_POINTER 7
  819. #define SQLITE_FCNTL_SYNC_OMITTED 8
  820. #define SQLITE_FCNTL_WIN32_AV_RETRY 9
  821. #define SQLITE_FCNTL_PERSIST_WAL 10
  822. #define SQLITE_FCNTL_OVERWRITE 11
  823. #define SQLITE_FCNTL_VFSNAME 12
  824. #define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13
  825. #define SQLITE_FCNTL_PRAGMA 14
  826. /*
  827. ** CAPI3REF: Mutex Handle
  828. **
  829. ** The mutex module within SQLite defines [sqlite3_mutex] to be an
  830. ** abstract type for a mutex object. The SQLite core never looks
  831. ** at the internal representation of an [sqlite3_mutex]. It only
  832. ** deals with pointers to the [sqlite3_mutex] object.
  833. **
  834. ** Mutexes are created using [sqlite3_mutex_alloc()].
  835. */
  836. typedef struct sqlite3_mutex sqlite3_mutex;
  837. /*
  838. ** CAPI3REF: OS Interface Object
  839. **
  840. ** An instance of the sqlite3_vfs object defines the interface between
  841. ** the SQLite core and the underlying operating system. The "vfs"
  842. ** in the name of the object stands for "virtual file system". See
  843. ** the [VFS | VFS documentation] for further information.
  844. **
  845. ** The value of the iVersion field is initially 1 but may be larger in
  846. ** future versions of SQLite. Additional fields may be appended to this
  847. ** object when the iVersion value is increased. Note that the structure
  848. ** of the sqlite3_vfs object changes in the transaction between
  849. ** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not
  850. ** modified.
  851. **
  852. ** The szOsFile field is the size of the subclassed [sqlite3_file]
  853. ** structure used by this VFS. mxPathname is the maximum length of
  854. ** a pathname in this VFS.
  855. **
  856. ** Registered sqlite3_vfs objects are kept on a linked list formed by
  857. ** the pNext pointer. The [sqlite3_vfs_register()]
  858. ** and [sqlite3_vfs_unregister()] interfaces manage this list
  859. ** in a thread-safe way. The [sqlite3_vfs_find()] interface
  860. ** searches the list. Neither the application code nor the VFS
  861. ** implementation should use the pNext pointer.
  862. **
  863. ** The pNext field is the only field in the sqlite3_vfs
  864. ** structure that SQLite will ever modify. SQLite will only access
  865. ** or modify this field while holding a particular static mutex.
  866. ** The application should never modify anything within the sqlite3_vfs
  867. ** object once the object has been registered.
  868. **
  869. ** The zName field holds the name of the VFS module. The name must
  870. ** be unique across all VFS modules.
  871. **
  872. ** [[sqlite3_vfs.xOpen]]
  873. ** ^SQLite guarantees that the zFilename parameter to xOpen
  874. ** is either a NULL pointer or string obtained
  875. ** from xFullPathname() with an optional suffix added.
  876. ** ^If a suffix is added to the zFilename parameter, it will
  877. ** consist of a single "-" character followed by no more than
  878. ** 11 alphanumeric and/or "-" characters.
  879. ** ^SQLite further guarantees that
  880. ** the string will be valid and unchanged until xClose() is
  881. ** called. Because of the previous sentence,
  882. ** the [sqlite3_file] can safely store a pointer to the
  883. ** filename if it needs to remember the filename for some reason.
  884. ** If the zFilename parameter to xOpen is a NULL pointer then xOpen
  885. ** must invent its own temporary name for the file. ^Whenever the
  886. ** xFilename parameter is NULL it will also be the case that the
  887. ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
  888. **
  889. ** The flags argument to xOpen() includes all bits set in
  890. ** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()]
  891. ** or [sqlite3_open16()] is used, then flags includes at least
  892. ** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE].
  893. ** If xOpen() opens a file read-only then it sets *pOutFlags to
  894. ** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set.
  895. **
  896. ** ^(SQLite will also add one of the following flags to the xOpen()
  897. ** call, depending on the object being opened:
  898. **
  899. ** <ul>
  900. ** <li> [SQLITE_OPEN_MAIN_DB]
  901. ** <li> [SQLITE_OPEN_MAIN_JOURNAL]
  902. ** <li> [SQLITE_OPEN_TEMP_DB]
  903. ** <li> [SQLITE_OPEN_TEMP_JOURNAL]
  904. ** <li> [SQLITE_OPEN_TRANSIENT_DB]
  905. ** <li> [SQLITE_OPEN_SUBJOURNAL]
  906. ** <li> [SQLITE_OPEN_MASTER_JOURNAL]
  907. ** <li> [SQLITE_OPEN_WAL]
  908. ** </ul>)^
  909. **
  910. ** The file I/O implementation can use the object type flags to
  911. ** change the way it deals with files. For example, an application
  912. ** that does not care about crash recovery or rollback might make
  913. ** the open of a journal file a no-op. Writes to this journal would
  914. ** also be no-ops, and any attempt to read the journal would return
  915. ** SQLITE_IOERR. Or the implementation might recognize that a database
  916. ** file will be doing page-aligned sector reads and writes in a random
  917. ** order and set up its I/O subsystem accordingly.
  918. **
  919. ** SQLite might also add one of the following flags to the xOpen method:
  920. **
  921. ** <ul>
  922. ** <li> [SQLITE_OPEN_DELETEONCLOSE]
  923. ** <li> [SQLITE_OPEN_EXCLUSIVE]
  924. ** </ul>
  925. **
  926. ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
  927. ** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE]
  928. ** will be set for TEMP databases and their journals, transient
  929. ** databases, and subjournals.
  930. **
  931. ** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
  932. ** with the [SQLITE_OPEN_CREATE] flag, which are both directly
  933. ** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
  934. ** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
  935. ** SQLITE_OPEN_CREATE, is used to indicate that file should always
  936. ** be created, and that it is an error if it already exists.
  937. ** It is <i>not</i> used to indicate the file should be opened
  938. ** for exclusive access.
  939. **
  940. ** ^At least szOsFile bytes of memory are allocated by SQLite
  941. ** to hold the [sqlite3_file] structure passed as the third
  942. ** argument to xOpen. The xOpen method does not have to
  943. ** allocate the structure; it should just fill it in. Note that
  944. ** the xOpen method must set the sqlite3_file.pMethods to either
  945. ** a valid [sqlite3_io_methods] object or to NULL. xOpen must do
  946. ** this even if the open fails. SQLite expects that the sqlite3_file.pMethods
  947. ** element will be valid after xOpen returns regardless of the success
  948. ** or failure of the xOpen call.
  949. **
  950. ** [[sqlite3_vfs.xAccess]]
  951. ** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
  952. ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
  953. ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
  954. ** to test whether a file is at least readable. The file can be a
  955. ** directory.
  956. **
  957. ** ^SQLite will always allocate at least mxPathname+1 bytes for the
  958. ** output buffer xFullPathname. The exact size of the output buffer
  959. ** is also passed as a parameter to both methods. If the output buffer
  960. ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
  961. ** handled as a fatal error by SQLite, vfs implementations should endeavor
  962. ** to prevent this by setting mxPathname to a sufficiently large value.
  963. **
  964. ** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
  965. ** interfaces are not strictly a part of the filesystem, but they are
  966. ** included in the VFS structure for completeness.
  967. ** The xRandomness() function attempts to return nBytes bytes
  968. ** of good-quality randomness into zOut. The return value is
  969. ** the actual number of bytes of randomness obtained.
  970. ** The xSleep() method causes the calling thread to sleep for at
  971. ** least the number of microseconds given. ^The xCurrentTime()
  972. ** method returns a Julian Day Number for the current date and time as
  973. ** a floating point value.
  974. ** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
  975. ** Day Number multiplied by 86400000 (the number of milliseconds in
  976. ** a 24-hour day).
  977. ** ^SQLite will use the xCurrentTimeInt64() method to get the current
  978. ** date and time if that method is available (if iVersion is 2 or
  979. ** greater and the function pointer is not NULL) and will fall back
  980. ** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
  981. **
  982. ** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
  983. ** are not used by the SQLite core. These optional interfaces are provided
  984. ** by some VFSes to facilitate testing of the VFS code. By overriding
  985. ** system calls with functions under its control, a test program can
  986. ** simulate faults and error conditions that would otherwise be difficult
  987. ** or impossible to induce. The set of system calls that can be overridden
  988. ** varies from one VFS to another, and from one version of the same VFS to the
  989. ** next. Applications that use these interfaces must be prepared for any
  990. ** or all of these interfaces to be NULL or for their behavior to change
  991. ** from one release to the next. Applications must not attempt to access
  992. ** any of these methods if the iVersion of the VFS is less than 3.
  993. */
  994. typedef struct sqlite3_vfs sqlite3_vfs;
  995. typedef void (*sqlite3_syscall_ptr)(void);
  996. struct sqlite3_vfs {
  997. int iVersion; /* Structure version number (currently 3) */
  998. int szOsFile; /* Size of subclassed sqlite3_file */
  999. int mxPathname; /* Maximum file pathname length */
  1000. sqlite3_vfs *pNext; /* Next registered VFS */
  1001. const char *zName; /* Name of this virtual file system */
  1002. void *pAppData; /* Pointer to application-specific data */
  1003. int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
  1004. int flags, int *pOutFlags);
  1005. int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
  1006. int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
  1007. int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
  1008. void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
  1009. void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
  1010. void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
  1011. void (*xDlClose)(sqlite3_vfs*, void*);
  1012. int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
  1013. int (*xSleep)(sqlite3_vfs*, int microseconds);
  1014. int (*xCurrentTime)(sqlite3_vfs*, double*);
  1015. int (*xGetLastError)(sqlite3_vfs*, int, char *);
  1016. /*
  1017. ** The methods above are in version 1 of the sqlite_vfs object
  1018. ** definition. Those that follow are added in version 2 or later
  1019. */
  1020. int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
  1021. /*
  1022. ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
  1023. ** Those below are for version 3 and greater.
  1024. */
  1025. int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
  1026. sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
  1027. const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
  1028. /*
  1029. ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
  1030. ** New fields may be appended in figure versions. The iVersion
  1031. ** value will increment whenever this happens.
  1032. */
  1033. };
  1034. /*
  1035. ** CAPI3REF: Flags for the xAccess VFS method
  1036. **
  1037. ** These integer constants can be used as the third parameter to
  1038. ** the xAccess method of an [sqlite3_vfs] object. They determine
  1039. ** what kind of permissions the xAccess method is looking for.
  1040. ** With SQLITE_ACCESS_EXISTS, the xAccess method
  1041. ** simply checks whether the file exists.
  1042. ** With SQLITE_ACCESS_READWRITE, the xAccess method
  1043. ** checks whether the named directory is both readable and writable
  1044. ** (in other words, if files can be added, removed, and renamed within
  1045. ** the directory).
  1046. ** The SQLITE_ACCESS_READWRITE constant is currently used only by the
  1047. ** [temp_store_directory pragma], though this could change in a future
  1048. ** release of SQLite.
  1049. ** With SQLITE_ACCESS_READ, the xAccess method
  1050. ** checks whether the file is readable. The SQLITE_ACCESS_READ constant is
  1051. ** currently unused, though it might be used in a future release of
  1052. ** SQLite.
  1053. */
  1054. #define SQLITE_ACCESS_EXISTS 0
  1055. #define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */
  1056. #define SQLITE_ACCESS_READ 2 /* Unused */
  1057. /*
  1058. ** CAPI3REF: Flags for the xShmLock VFS method
  1059. **
  1060. ** These integer constants define the various locking operations
  1061. ** allowed by the xShmLock method of [sqlite3_io_methods]. The
  1062. ** following are the only legal combinations of flags to the
  1063. ** xShmLock method:
  1064. **
  1065. ** <ul>
  1066. ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
  1067. ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
  1068. ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
  1069. ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
  1070. ** </ul>
  1071. **
  1072. ** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
  1073. ** was given no the corresponding lock.
  1074. **
  1075. ** The xShmLock method can transition between unlocked and SHARED or
  1076. ** between unlocked and EXCLUSIVE. It cannot transition between SHARED
  1077. ** and EXCLUSIVE.
  1078. */
  1079. #define SQLITE_SHM_UNLOCK 1
  1080. #define SQLITE_SHM_LOCK 2
  1081. #define SQLITE_SHM_SHARED 4
  1082. #define SQLITE_SHM_EXCLUSIVE 8
  1083. /*
  1084. ** CAPI3REF: Maximum xShmLock index
  1085. **
  1086. ** The xShmLock method on [sqlite3_io_methods] may use values
  1087. ** between 0 and this upper bound as its "offset" argument.
  1088. ** The SQLite core will never attempt to acquire or release a
  1089. ** lock outside of this range
  1090. */
  1091. #define SQLITE_SHM_NLOCK 8
  1092. /*
  1093. ** CAPI3REF: Initialize The SQLite Library
  1094. **
  1095. ** ^The sqlite3_initialize() routine initializes the
  1096. ** SQLite library. ^The sqlite3_shutdown() routine
  1097. ** deallocates any resources that were allocated by sqlite3_initialize().
  1098. ** These routines are designed to aid in process initialization and
  1099. ** shutdown on embedded systems. Workstation applications using
  1100. ** SQLite normally do not need to invoke either of these routines.
  1101. **
  1102. ** A call to sqlite3_initialize() is an "effective" call if it is
  1103. ** the first time sqlite3_initialize() is invoked during the lifetime of
  1104. ** the process, or if it is the first time sqlite3_initialize() is invoked
  1105. ** following a call to sqlite3_shutdown(). ^(Only an effective call
  1106. ** of sqlite3_initialize() does any initialization. All other calls
  1107. ** are harmless no-ops.)^
  1108. **
  1109. ** A call to sqlite3_shutdown() is an "effective" call if it is the first
  1110. ** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only
  1111. ** an effective call to sqlite3_shutdown() does any deinitialization.
  1112. ** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
  1113. **
  1114. ** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
  1115. ** is not. The sqlite3_shutdown() interface must only be called from a
  1116. ** single thread. All open [database connections] must be closed and all
  1117. ** other SQLite resources must be deallocated prior to invoking
  1118. ** sqlite3_shutdown().
  1119. **
  1120. ** Among other things, ^sqlite3_initialize() will invoke
  1121. ** sqlite3_os_init(). Similarly, ^sqlite3_shutdown()
  1122. ** will invoke sqlite3_os_end().
  1123. **
  1124. ** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
  1125. ** ^If for some reason, sqlite3_initialize() is unable to initialize
  1126. ** the library (perhaps it is unable to allocate a needed resource such
  1127. ** as a mutex) it returns an [error code] other than [SQLITE_OK].
  1128. **
  1129. ** ^The sqlite3_initialize() routine is called internally by many other
  1130. ** SQLite interfaces so that an application usually does not need to
  1131. ** invoke sqlite3_initialize() directly. For example, [sqlite3_open()]
  1132. ** calls sqlite3_initialize() so the SQLite library will be automatically
  1133. ** initialized when [sqlite3_open()] is called if it has not be initialized
  1134. ** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
  1135. ** compile-time option, then the automatic calls to sqlite3_initialize()
  1136. ** are omitted and the application must call sqlite3_initialize() directly
  1137. ** prior to using any other SQLite interface. For maximum portability,
  1138. ** it is recommended that applications always invoke sqlite3_initialize()
  1139. ** directly prior to using any other SQLite interface. Future releases
  1140. ** of SQLite may require this. In other words, the behavior exhibited
  1141. ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
  1142. ** default behavior in some future release of SQLite.
  1143. **
  1144. ** The sqlite3_os_init() routine does operating-system specific
  1145. ** initialization of the SQLite library. The sqlite3_os_end()
  1146. ** routine undoes the effect of sqlite3_os_init(). Typical tasks
  1147. ** performed by these routines include allocation or deallocation
  1148. ** of static resources, initialization of global variables,
  1149. ** setting up a default [sqlite3_vfs] module, or setting up
  1150. ** a default configuration using [sqlite3_config()].
  1151. **
  1152. ** The application should never invoke either sqlite3_os_init()
  1153. ** or sqlite3_os_end() directly. The application should only invoke
  1154. ** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init()
  1155. ** interface is called automatically by sqlite3_initialize() and
  1156. ** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate
  1157. ** implementations for sqlite3_os_init() and sqlite3_os_end()
  1158. ** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
  1159. ** When [custom builds | built for other platforms]
  1160. ** (using the [SQLITE_OS_OTHER=1] compile-time
  1161. ** option) the application must supply a suitable implementation for
  1162. ** sqlite3_os_init() and sqlite3_os_end(). An application-supplied
  1163. ** implementation of sqlite3_os_init() or sqlite3_os_end()
  1164. ** must return [SQLITE_OK] on success and some other [error code] upon
  1165. ** failure.
  1166. */
  1167. SQLITE_API int sqlite3_initialize(void);
  1168. SQLITE_API int sqlite3_shutdown(void);
  1169. SQLITE_API int sqlite3_os_init(void);
  1170. SQLITE_API int sqlite3_os_end(void);
  1171. /*
  1172. ** CAPI3REF: Configuring The SQLite Library
  1173. **
  1174. ** The sqlite3_config() interface is used to make global configuration
  1175. ** changes to SQLite in order to tune SQLite to the specific needs of
  1176. ** the application. The default configuration is recommended for most
  1177. ** applications and so this routine is usually not necessary. It is
  1178. ** provided to support rare applications with unusual needs.
  1179. **
  1180. ** The sqlite3_config() interface is not threadsafe. The application
  1181. ** must insure that no other SQLite interfaces are invoked by other
  1182. ** threads while sqlite3_config() is running. Furthermore, sqlite3_config()
  1183. ** may only be invoked prior to library initialization using
  1184. ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
  1185. ** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
  1186. ** [sqlite3_shutdown()] then it will return SQLITE_MISUSE.
  1187. ** Note, however, that ^sqlite3_config() can be called as part of the
  1188. ** implementation of an application-defined [sqlite3_os_init()].
  1189. **
  1190. ** The first argument to sqlite3_config() is an integer
  1191. ** [configuration option] that determines
  1192. ** what property of SQLite is to be configured. Subsequent arguments
  1193. ** vary depending on the [configuration option]
  1194. ** in the first argument.
  1195. **
  1196. ** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
  1197. ** ^If the option is unknown or SQLite is unable to set the option
  1198. ** then this routine returns a non-zero [error code].
  1199. */
  1200. SQLITE_API int sqlite3_config(int, ...);
  1201. /*
  1202. ** CAPI3REF: Configure database connections
  1203. **
  1204. ** The sqlite3_db_config() interface is used to make configuration
  1205. ** changes to a [database connection]. The interface is similar to
  1206. ** [sqlite3_config()] except that the changes apply to a single
  1207. ** [database connection] (specified in the first argument).
  1208. **
  1209. ** The second argument to sqlite3_db_config(D,V,...) is the
  1210. ** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code
  1211. ** that indicates what aspect of the [database connection] is being configured.
  1212. ** Subsequent arguments vary depending on the configuration verb.
  1213. **
  1214. ** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
  1215. ** the call is considered successful.
  1216. */
  1217. SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...);
  1218. /*
  1219. ** CAPI3REF: Memory Allocation Routines
  1220. **
  1221. ** An instance of this object defines the interface between SQLite
  1222. ** and low-level memory allocation routines.
  1223. **
  1224. ** This object is used in only one place in the SQLite interface.
  1225. ** A pointer to an instance of this object is the argument to
  1226. ** [sqlite3_config()] when the configuration option is
  1227. ** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].
  1228. ** By creating an instance of this object
  1229. ** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
  1230. ** during configuration, an application can specify an alternative
  1231. ** memory allocation subsystem for SQLite to use for all of its
  1232. ** dynamic memory needs.
  1233. **
  1234. ** Note that SQLite comes with several [built-in memory allocators]
  1235. ** that are perfectly adequate for the overwhelming majority of applications
  1236. ** and that this object is only useful to a tiny minority of applications
  1237. ** with specialized memory allocation requirements. This object is
  1238. ** also used during testing of SQLite in order to specify an alternative
  1239. ** memory allocator that simulates memory out-of-memory conditions in
  1240. ** order to verify that SQLite recovers gracefully from such
  1241. ** conditions.
  1242. **
  1243. ** The xMalloc, xRealloc, and xFree methods must work like the
  1244. ** malloc(), realloc() and free() functions from the standard C library.
  1245. ** ^SQLite guarantees that the second argument to
  1246. ** xRealloc is always a value returned by a prior call to xRoundup.
  1247. **
  1248. ** xSize should return the allocated size of a memory allocation
  1249. ** previously obtained from xMalloc or xRealloc. The allocated size
  1250. ** is always at least as big as the requested size but may be larger.
  1251. **
  1252. ** The xRoundup method returns what would be the allocated size of
  1253. ** a memory allocation given a particular requested size. Most memory
  1254. ** allocators round up memory allocations at least to the next multiple
  1255. ** of 8. Some allocators round up to a larger multiple or to a power of 2.
  1256. ** Every memory allocation request coming in through [sqlite3_malloc()]
  1257. ** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0,
  1258. ** that causes the corresponding memory allocation to fail.
  1259. **
  1260. ** The xInit method initializes the memory allocator. (For example,
  1261. ** it might allocate any require mutexes or initialize internal data
  1262. ** structures. The xShutdown method is invoked (indirectly) by
  1263. ** [sqlite3_shutdown()] and should deallocate any resources acquired
  1264. ** by xInit. The pAppData pointer is used as the only parameter to
  1265. ** xInit and xShutdown.
  1266. **
  1267. ** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes
  1268. ** the xInit method, so the xInit method need not be threadsafe. The
  1269. ** xShutdown method is only called from [sqlite3_shutdown()] so it does
  1270. ** not need to be threadsafe either. For all other methods, SQLite
  1271. ** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
  1272. ** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
  1273. ** it is by default) and so the methods are automatically serialized.
  1274. ** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
  1275. ** methods must be threadsafe or else make their own arrangements for
  1276. ** serialization.
  1277. **
  1278. ** SQLite will never invoke xInit() more than once without an intervening
  1279. ** call to xShutdown().
  1280. */
  1281. typedef struct sqlite3_mem_methods sqlite3_mem_methods;
  1282. struct sqlite3_mem_methods {
  1283. void *(*xMalloc)(int); /* Memory allocation function */
  1284. void (*xFree)(void*); /* Free a prior allocation */
  1285. void *(*xRealloc)(void*,int); /* Resize an allocation */
  1286. int (*xSize)(void*); /* Return the size of an allocation */
  1287. int (*xRoundup)(int); /* Round up request size to allocation size */
  1288. int (*xInit)(void*); /* Initialize the memory allocator */
  1289. void (*xShutdown)(void*); /* Deinitialize the memory allocator */
  1290. void *pAppData; /* Argument to xInit() and xShutdown() */
  1291. };
  1292. /*
  1293. ** CAPI3REF: Configuration Options
  1294. ** KEYWORDS: {configuration option}
  1295. **
  1296. ** These constants are the available integer configuration options that
  1297. ** can be passed as the first argument to the [sqlite3_config()] interface.
  1298. **
  1299. ** New configuration options may be added in future releases of SQLite.
  1300. ** Existing configuration options might be discontinued. Applications
  1301. ** should check the return code from [sqlite3_config()] to make sure that
  1302. ** the call worked. The [sqlite3_config()] interface will return a
  1303. ** non-zero [error code] if a discontinued or unsupported configuration option
  1304. ** is invoked.
  1305. **
  1306. ** <dl>
  1307. ** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
  1308. ** <dd>There are no arguments to this option. ^This option sets the
  1309. ** [threading mode] to Single-thread. In other words, it disables
  1310. ** all mutexing and puts SQLite into a mode where it can only be used
  1311. ** by a single thread. ^If SQLite is compiled with
  1312. ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
  1313. ** it is not possible to change the [threading mode] from its default
  1314. ** value of Single-thread and so [sqlite3_config()] will return
  1315. ** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
  1316. ** configuration option.</dd>
  1317. **
  1318. ** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt>
  1319. ** <dd>There are no arguments to this option. ^This option sets the
  1320. ** [threading mode] to Multi-thread. In other words, it disables
  1321. ** mutexing on [database connection] and [prepared statement] objects.
  1322. ** The application is responsible for serializing access to
  1323. ** [database connections] and [prepared statements]. But other mutexes
  1324. ** are enabled so that SQLite will be safe to use in a multi-threaded
  1325. ** environment as long as no two threads attempt to use the same
  1326. ** [database connection] at the same time. ^If SQLite is compiled with
  1327. ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
  1328. ** it is not possible to set the Multi-thread [threading mode] and
  1329. ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
  1330. ** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
  1331. **
  1332. ** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt>
  1333. ** <dd>There are no arguments to this option. ^This option sets the
  1334. ** [threading mode] to Serialized. In other words, this option enables
  1335. ** all mutexes including the recursive
  1336. ** mutexes on [database connection] and [prepared statement] objects.
  1337. ** In this mode (which is the default when SQLite is compiled with
  1338. ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
  1339. ** to [database connections] and [prepared statements] so that the
  1340. ** application is free to use the same [database connection] or the
  1341. ** same [prepared statement] in different threads at the same time.
  1342. ** ^If SQLite is compiled with
  1343. ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
  1344. ** it is not possible to set the Serialized [threading mode] and
  1345. ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
  1346. ** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
  1347. **
  1348. ** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt>
  1349. ** <dd> ^(This option takes a single argument which is a pointer to an
  1350. ** instance of the [sqlite3_mem_methods] structure. The argument specifies
  1351. ** alternative low-level memory allocation routines to be used in place of
  1352. ** the memory allocation routines built into SQLite.)^ ^SQLite makes
  1353. ** its own private copy of the content of the [sqlite3_mem_methods] structure
  1354. ** before the [sqlite3_config()] call returns.</dd>
  1355. **
  1356. ** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt>
  1357. ** <dd> ^(This option takes a single argument which is a pointer to an
  1358. ** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods]
  1359. ** structure is filled with the currently defined memory allocation routines.)^
  1360. ** This option can be used to overload the default memory allocation
  1361. ** routines with a wrapper that simulations memory allocation failure or
  1362. ** tracks memory usage, for example. </dd>
  1363. **
  1364. ** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt>
  1365. ** <dd> ^This option takes single argument of type int, interpreted as a
  1366. ** boolean, which enables or disables the collection of memory allocation
  1367. ** statistics. ^(When memory allocation statistics are disabled, the
  1368. ** following SQLite interfaces become non-operational:
  1369. ** <ul>
  1370. ** <li> [sqlite3_memory_used()]
  1371. ** <li> [sqlite3_memory_highwater()]
  1372. ** <li> [sqlite3_soft_heap_limit64()]
  1373. ** <li> [sqlite3_status()]
  1374. ** </ul>)^
  1375. ** ^Memory allocation statistics are enabled by default unless SQLite is
  1376. ** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
  1377. ** allocation statistics are disabled by default.
  1378. ** </dd>
  1379. **
  1380. ** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt>
  1381. ** <dd> ^This option specifies a static memory buffer that SQLite can use for
  1382. ** scratch memory. There are three arguments: A pointer an 8-byte
  1383. ** aligned memory buffer from which the scratch allocations will be
  1384. ** drawn, the size of each scratch allocation (sz),
  1385. ** and the maximum number of scratch allocations (N). The sz
  1386. ** argument must be a multiple of 16.
  1387. ** The first argument must be a pointer to an 8-byte aligned buffer
  1388. ** of at least sz*N bytes of memory.
  1389. ** ^SQLite will use no more than two scratch buffers per thread. So
  1390. ** N should be set to twice the expected maximum number of threads.
  1391. ** ^SQLite will never require a scratch buffer that is more than 6
  1392. ** times the database page size. ^If SQLite needs needs additional
  1393. ** scratch memory beyond what is provided by this configuration option, then
  1394. ** [sqlite3_malloc()] will be used to obtain the memory needed.</dd>
  1395. **
  1396. ** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>
  1397. ** <dd> ^This option specifies a static memory buffer that SQLite can use for
  1398. ** the database page cache with the default page cache implementation.
  1399. ** This configuration should not be used if an application-define page
  1400. ** cache implementation is loaded using the SQLITE_CONFIG_PCACHE2 option.
  1401. ** There are three arguments to this option: A pointer to 8-byte aligned
  1402. ** memory, the size of each page buffer (sz), and the number of pages (N).
  1403. ** The sz argument should be the size of the largest database page
  1404. ** (a power of two between 512 and 32768) plus a little extra for each
  1405. ** page header. ^The page header size is 20 to 40 bytes depending on
  1406. ** the host architecture. ^It is harmless, apart from the wasted memory,
  1407. ** to make sz a little too large. The first
  1408. ** argument should point to an allocation of at least sz*N bytes of memory.
  1409. ** ^SQLite will use the memory provided by the first argument to satisfy its
  1410. ** memory needs for the first N pages that it adds to cache. ^If additional
  1411. ** page cache memory is needed beyond what is provided by this option, then
  1412. ** SQLite goes to [sqlite3_malloc()] for the additional storage space.
  1413. ** The pointer in the first argument must
  1414. ** be aligned to an 8-byte boundary or subsequent behavior of SQLite
  1415. ** will be undefined.</dd>
  1416. **
  1417. ** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt>
  1418. ** <dd> ^This option specifies a static memory buffer that SQLite will use
  1419. ** for all of its dynamic memory allocation needs beyond those provided
  1420. ** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE].
  1421. ** There are three arguments: An 8-byte aligned pointer to the memory,
  1422. ** the number of bytes in the memory buffer, and the minimum allocation size.
  1423. ** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
  1424. ** to using its default memory allocator (the system malloc() implementation),
  1425. ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the
  1426. ** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or
  1427. ** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory
  1428. ** allocator is engaged to handle all of SQLites memory allocation needs.
  1429. ** The first pointer (the memory pointer) must be aligned to an 8-byte
  1430. ** boundary or subsequent behavior of SQLite will be undefined.
  1431. ** The minimum allocation size is capped at 2**12. Reasonable values
  1432. ** for the minimum allocation size are 2**5 through 2**8.</dd>
  1433. **
  1434. ** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt>
  1435. ** <dd> ^(This option takes a single argument which is a pointer to an
  1436. ** instance of the [sqlite3_mutex_methods] structure. The argument specifies
  1437. ** alternative low-level mutex routines to be used in place
  1438. ** the mutex routines built into SQLite.)^ ^SQLite makes a copy of the
  1439. ** content of the [sqlite3_mutex_methods] structure before the call to
  1440. ** [sqlite3_config()] returns. ^If SQLite is compiled with
  1441. ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
  1442. ** the entire mutexing subsystem is omitted from the build and hence calls to
  1443. ** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
  1444. ** return [SQLITE_ERROR].</dd>
  1445. **
  1446. ** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt>
  1447. ** <dd> ^(This option takes a single argument which is a pointer to an
  1448. ** instance of the [sqlite3_mutex_methods] structure. The
  1449. ** [sqlite3_mutex_methods]
  1450. ** structure is filled with the currently defined mutex routines.)^
  1451. ** This option can be used to overload the default mutex allocation
  1452. ** routines with a wrapper used to track mutex usage for performance
  1453. ** profiling or testing, for example. ^If SQLite is compiled with
  1454. ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
  1455. ** the entire mutexing subsystem is omitted from the build and hence calls to
  1456. ** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
  1457. ** return [SQLITE_ERROR].</dd>
  1458. **
  1459. ** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt>
  1460. ** <dd> ^(This option takes two arguments that determine the default
  1461. ** memory allocation for the lookaside memory allocator on each
  1462. ** [database connection]. The first argument is the
  1463. ** size of each lookaside buffer slot and the second is the number of
  1464. ** slots allocated to each database connection.)^ ^(This option sets the
  1465. ** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
  1466. ** verb to [sqlite3_db_config()] can be used to change the lookaside
  1467. ** configuration on individual connections.)^ </dd>
  1468. **
  1469. ** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt>
  1470. ** <dd> ^(This option takes a single argument which is a pointer to
  1471. ** an [sqlite3_pcache_methods2] object. This object specifies the interface
  1472. ** to a custom page cache implementation.)^ ^SQLite makes a copy of the
  1473. ** object and uses it for page cache memory allocations.</dd>
  1474. **
  1475. ** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt>
  1476. ** <dd> ^(This option takes a single argument which is a pointer to an
  1477. ** [sqlite3_pcache_methods2] object. SQLite copies of the current
  1478. ** page cache implementation into that object.)^ </dd>
  1479. **
  1480. ** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>
  1481. ** <dd> ^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
  1482. ** function with a call signature of void(*)(void*,int,const char*),
  1483. ** and a pointer to void. ^If the function pointer is not NULL, it is
  1484. ** invoked by [sqlite3_log()] to process each logging event. ^If the
  1485. ** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
  1486. ** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
  1487. ** passed through as the first parameter to the application-defined logger
  1488. ** function whenever that function is invoked. ^The second parameter to
  1489. ** the logger function is a copy of the first parameter to the corresponding
  1490. ** [sqlite3_log()] call and is intended to be a [result code] or an
  1491. ** [extended result code]. ^The third parameter passed to the logger is
  1492. ** log message after formatting via [sqlite3_snprintf()].
  1493. ** The SQLite logging interface is not reentrant; the logger function
  1494. ** supplied by the application must not invoke any SQLite interface.
  1495. ** In a multi-threaded application, the application-defined logger
  1496. ** function must be threadsafe. </dd>
  1497. **
  1498. ** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI
  1499. ** <dd> This option takes a single argument of type int. If non-zero, then
  1500. ** URI handling is globally enabled. If the parameter is zero, then URI handling
  1501. ** is globally disabled. If URI handling is globally enabled, all filenames
  1502. ** passed to [sqlite3_open()], [sqlite3_open_v2()], [sqlite3_open16()] or
  1503. ** specified as part of [ATTACH] commands are interpreted as URIs, regardless
  1504. ** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
  1505. ** connection is opened. If it is globally disabled, filenames are
  1506. ** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
  1507. ** database connection is opened. By default, URI handling is globally
  1508. ** disabled. The default value may be changed by compiling with the
  1509. ** [SQLITE_USE_URI] symbol defined.
  1510. **
  1511. ** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]]
  1512. ** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFNIG_GETPCACHE
  1513. ** <dd> These options are obsolete and should not be used by new code.
  1514. ** They are retained for backwards compatibility but are now no-ops.
  1515. ** </dl>
  1516. */
  1517. #define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */
  1518. #define SQLITE_CONFIG_MULTITHREAD 2 /* nil */
  1519. #define SQLITE_CONFIG_SERIALIZED 3 /* nil */
  1520. #define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */
  1521. #define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */
  1522. #define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */
  1523. #define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */
  1524. #define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */
  1525. #define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */
  1526. #define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */
  1527. #define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */
  1528. /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */
  1529. #define SQLITE_CONFIG_LOOKASIDE 13 /* int int */
  1530. #define SQLITE_CONFIG_PCACHE 14 /* no-op */
  1531. #define SQLITE_CONFIG_GETPCACHE 15 /* no-op */
  1532. #define SQLITE_CONFIG_LOG 16 /* xFunc, void* */
  1533. #define SQLITE_CONFIG_URI 17 /* int */
  1534. #define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */
  1535. #define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */
  1536. /*
  1537. ** CAPI3REF: Database Connection Configuration Options
  1538. **
  1539. ** These constants are the available integer configuration options that
  1540. ** can be passed as the second argument to the [sqlite3_db_config()] interface.
  1541. **
  1542. ** New configuration options may be added in future releases of SQLite.
  1543. ** Existing configuration options might be discontinued. Applications
  1544. ** should check the return code from [sqlite3_db_config()] to make sure that
  1545. ** the call worked. ^The [sqlite3_db_config()] interface will return a
  1546. ** non-zero [error code] if a discontinued or unsupported configuration option
  1547. ** is invoked.
  1548. **
  1549. ** <dl>
  1550. ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
  1551. ** <dd> ^This option takes three additional arguments that determine the
  1552. ** [lookaside memory allocator] configuration for the [database connection].
  1553. ** ^The first argument (the third parameter to [sqlite3_db_config()] is a
  1554. ** pointer to a memory buffer to use for lookaside memory.
  1555. ** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
  1556. ** may be NULL in which case SQLite will allocate the
  1557. ** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
  1558. ** size of each lookaside buffer slot. ^The third argument is the number of
  1559. ** slots. The size of the buffer in the first argument must be greater than
  1560. ** or equal to the product of the second and third arguments. The buffer
  1561. ** must be aligned to an 8-byte boundary. ^If the second argument to
  1562. ** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
  1563. ** rounded down to the next smaller multiple of 8. ^(The lookaside memory
  1564. ** configuration for a database connection can only be changed when that
  1565. ** connection is not currently using lookaside memory, or in other words
  1566. ** when the "current value" returned by
  1567. ** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero.
  1568. ** Any attempt to change the lookaside memory configuration when lookaside
  1569. ** memory is in use leaves the configuration unchanged and returns
  1570. ** [SQLITE_BUSY].)^</dd>
  1571. **
  1572. ** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
  1573. ** <dd> ^This option is used to enable or disable the enforcement of
  1574. ** [foreign key constraints]. There should be two additional arguments.
  1575. ** The first argument is an integer which is 0 to disable FK enforcement,
  1576. ** positive to enable FK enforcement or negative to leave FK enforcement
  1577. ** unchanged. The second parameter is a pointer to an integer into which
  1578. ** is written 0 or 1 to indicate whether FK enforcement is off or on
  1579. ** following this call. The second parameter may be a NULL pointer, in
  1580. ** which case the FK enforcement setting is not reported back. </dd>
  1581. **
  1582. ** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
  1583. ** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
  1584. ** There should be two additional arguments.
  1585. ** The first argument is an integer which is 0 to disable triggers,
  1586. ** positive to enable triggers or negative to leave the setting unchanged.
  1587. ** The second parameter is a pointer to an integer into which
  1588. ** is written 0 or 1 to indicate whether triggers are disabled or enabled
  1589. ** following this call. The second parameter may be a NULL pointer, in
  1590. ** which case the trigger setting is not reported back. </dd>
  1591. **
  1592. ** </dl>
  1593. */
  1594. #define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */
  1595. #define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */
  1596. #define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */
  1597. /*
  1598. ** CAPI3REF: Enable Or Disable Extended Result Codes
  1599. **
  1600. ** ^The sqlite3_extended_result_codes() routine enables or disables the
  1601. ** [extended result codes] feature of SQLite. ^The extended result
  1602. ** codes are disabled by default for historical compatibility.
  1603. */
  1604. SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff);
  1605. /*
  1606. ** CAPI3REF: Last Insert Rowid
  1607. **
  1608. ** ^Each entry in an SQLite table has a unique 64-bit signed
  1609. ** integer key called the [ROWID | "rowid"]. ^The rowid is always available
  1610. ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
  1611. ** names are not also used by explicitly declared columns. ^If
  1612. ** the table has a column of type [INTEGER PRIMARY KEY] then that column
  1613. ** is another alias for the rowid.
  1614. **
  1615. ** ^This routine returns the [rowid] of the most recent
  1616. ** successful [INSERT] into the database from the [database connection]
  1617. ** in the first argument. ^As of SQLite version 3.7.7, this routines
  1618. ** records the last insert rowid of both ordinary tables and [virtual tables].
  1619. ** ^If no successful [INSERT]s
  1620. ** have ever occurred on that database connection, zero is returned.
  1621. **
  1622. ** ^(If an [INSERT] occurs within a trigger or within a [virtual table]
  1623. ** method, then this routine will return the [rowid] of the inserted
  1624. ** row as long as the trigger or virtual table method is running.
  1625. ** But once the trigger or virtual table method ends, the value returned
  1626. ** by this routine reverts to what it was before the trigger or virtual
  1627. ** table method began.)^
  1628. **
  1629. ** ^An [INSERT] that fails due to a constraint violation is not a
  1630. ** successful [INSERT] and does not change the value returned by this
  1631. ** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
  1632. ** and INSERT OR ABORT make no changes to the return value of this
  1633. ** routine when their insertion fails. ^(When INSERT OR REPLACE
  1634. ** encounters a constraint violation, it does not fail. The
  1635. ** INSERT continues to completion after deleting rows that caused
  1636. ** the constraint problem so INSERT OR REPLACE will always change
  1637. ** the return value of this interface.)^
  1638. **
  1639. ** ^For the purposes of this routine, an [INSERT] is considered to
  1640. ** be successful even if it is subsequently rolled back.
  1641. **
  1642. ** This function is accessible to SQL statements via the
  1643. ** [last_insert_rowid() SQL function].
  1644. **
  1645. ** If a separate thread performs a new [INSERT] on the same
  1646. ** database connection while the [sqlite3_last_insert_rowid()]
  1647. ** function is running and thus changes the last insert [rowid],
  1648. ** then the value returned by [sqlite3_last_insert_rowid()] is
  1649. ** unpredictable and might not equal either the old or the new
  1650. ** last insert [rowid].
  1651. */
  1652. SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
  1653. /*
  1654. ** CAPI3REF: Count The Number Of Rows Modified
  1655. **
  1656. ** ^This function returns the number of database rows that were changed
  1657. ** or inserted or deleted by the most recently completed SQL statement
  1658. ** on the [database connection] specified by the first parameter.
  1659. ** ^(Only changes that are directly specified by the [INSERT], [UPDATE],
  1660. ** or [DELETE] statement are counted. Auxiliary changes caused by
  1661. ** triggers or [foreign key actions] are not counted.)^ Use the
  1662. ** [sqlite3_total_changes()] function to find the total number of changes
  1663. ** including changes caused by triggers and foreign key actions.
  1664. **
  1665. ** ^Changes to a view that are simulated by an [INSTEAD OF trigger]
  1666. ** are not counted. Only real table changes are counted.
  1667. **
  1668. ** ^(A "row change" is a change to a single row of a single table
  1669. ** caused by an INSERT, DELETE, or UPDATE statement. Rows that
  1670. ** are changed as side effects of [REPLACE] constraint resolution,
  1671. ** rollback, ABORT processing, [DROP TABLE], or by any other
  1672. ** mechanisms do not count as direct row changes.)^
  1673. **
  1674. ** A "trigger context" is a scope of execution that begins and
  1675. ** ends with the script of a [CREATE TRIGGER | trigger].
  1676. ** Most SQL statements are
  1677. ** evaluated outside of any trigger. This is the "top level"
  1678. ** trigger context. If a trigger fires from the top level, a
  1679. ** new trigger context is entered for the duration of that one
  1680. ** trigger. Subtriggers create subcontexts for their duration.
  1681. **
  1682. ** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does
  1683. ** not create a new trigger context.
  1684. **
  1685. ** ^This function returns the number of direct row changes in the
  1686. ** most recent INSERT, UPDATE, or DELETE statement within the same
  1687. ** trigger context.
  1688. **
  1689. ** ^Thus, when called from the top level, this function returns the
  1690. ** number of changes in the most recent INSERT, UPDATE, or DELETE
  1691. ** that also occurred at the top level. ^(Within the body of a trigger,
  1692. ** the sqlite3_changes() interface can be called to find the number of
  1693. ** changes in the most recently completed INSERT, UPDATE, or DELETE
  1694. ** statement within the body of the same trigger.
  1695. ** However, the number returned does not include changes
  1696. ** caused by subtriggers since those have their own context.)^
  1697. **
  1698. ** See also the [sqlite3_total_changes()] interface, the
  1699. ** [count_changes pragma], and the [changes() SQL function].
  1700. **
  1701. ** If a separate thread makes changes on the same database connection
  1702. ** while [sqlite3_changes()] is running then the value returned
  1703. ** is unpredictable and not meaningful.
  1704. */
  1705. SQLITE_API int sqlite3_changes(sqlite3*);
  1706. /*
  1707. ** CAPI3REF: Total Number Of Rows Modified
  1708. **
  1709. ** ^This function returns the number of row changes caused by [INSERT],
  1710. ** [UPDATE] or [DELETE] statements since the [database connection] was opened.
  1711. ** ^(The count returned by sqlite3_total_changes() includes all changes
  1712. ** from all [CREATE TRIGGER | trigger] contexts and changes made by
  1713. ** [foreign key actions]. However,
  1714. ** the count does not include changes used to implement [REPLACE] constraints,
  1715. ** do rollbacks or ABORT processing, or [DROP TABLE] processing. The
  1716. ** count does not include rows of views that fire an [INSTEAD OF trigger],
  1717. ** though if the INSTEAD OF trigger makes changes of its own, those changes
  1718. ** are counted.)^
  1719. ** ^The sqlite3_total_changes() function counts the changes as soon as
  1720. ** the statement that makes them is completed (when the statement handle
  1721. ** is passed to [sqlite3_reset()] or [sqlite3_finalize()]).
  1722. **
  1723. ** See also the [sqlite3_changes()] interface, the
  1724. ** [count_changes pragma], and the [total_changes() SQL function].
  1725. **
  1726. ** If a separate thread makes changes on the same database connection
  1727. ** while [sqlite3_total_changes()] is running then the value
  1728. ** returned is unpredictable and not meaningful.
  1729. */
  1730. SQLITE_API int sqlite3_total_changes(sqlite3*);
  1731. /*
  1732. ** CAPI3REF: Interrupt A Long-Running Query
  1733. **
  1734. ** ^This function causes any pending database operation to abort and
  1735. ** return at its earliest opportunity. This routine is typically
  1736. ** called in response to a user action such as pressing "Cancel"
  1737. ** or Ctrl-C where the user wants a long query operation to halt
  1738. ** immediately.
  1739. **
  1740. ** ^It is safe to call this routine from a thread different from the
  1741. ** thread that is currently running the database operation. But it
  1742. ** is not safe to call this routine with a [database connection] that
  1743. ** is closed or might close before sqlite3_interrupt() returns.
  1744. **
  1745. ** ^If an SQL operation is very nearly finished at the time when
  1746. ** sqlite3_interrupt() is called, then it might not have an opportunity
  1747. ** to be interrupted and might continue to completion.
  1748. **
  1749. ** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
  1750. ** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
  1751. ** that is inside an explicit transaction, then the entire transaction
  1752. ** will be rolled back automatically.
  1753. **
  1754. ** ^The sqlite3_interrupt(D) call is in effect until all currently running
  1755. ** SQL statements on [database connection] D complete. ^Any new SQL statements
  1756. ** that are started after the sqlite3_interrupt() call and before the
  1757. ** running statements reaches zero are interrupted as if they had been
  1758. ** running prior to the sqlite3_interrupt() call. ^New SQL statements
  1759. ** that are started after the running statement count reaches zero are
  1760. ** not effected by the sqlite3_interrupt().
  1761. ** ^A call to sqlite3_interrupt(D) that occurs when there are no running
  1762. ** SQL statements is a no-op and has no effect on SQL statements
  1763. ** that are started after the sqlite3_interrupt() call returns.
  1764. **
  1765. ** If the database connection closes while [sqlite3_interrupt()]
  1766. ** is running then bad things will likely happen.
  1767. */
  1768. SQLITE_API void sqlite3_interrupt(sqlite3*);
  1769. /*
  1770. ** CAPI3REF: Determine If An SQL Statement Is Complete
  1771. **
  1772. ** These routines are useful during command-line input to determine if the
  1773. ** currently entered text seems to form a complete SQL statement or
  1774. ** if additional input is needed before sending the text into
  1775. ** SQLite for parsing. ^These routines return 1 if the input string
  1776. ** appears to be a complete SQL statement. ^A statement is judged to be
  1777. ** complete if it ends with a semicolon token and is not a prefix of a
  1778. ** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within
  1779. ** string literals or quoted identifier names or comments are not
  1780. ** independent tokens (they are part of the token in which they are
  1781. ** embedded) and thus do not count as a statement terminator. ^Whitespace
  1782. ** and comments that follow the final semicolon are ignored.
  1783. **
  1784. ** ^These routines return 0 if the statement is incomplete. ^If a
  1785. ** memory allocation fails, then SQLITE_NOMEM is returned.
  1786. **
  1787. ** ^These routines do not parse the SQL statements thus
  1788. ** will not detect syntactically incorrect SQL.
  1789. **
  1790. ** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior
  1791. ** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
  1792. ** automatically by sqlite3_complete16(). If that initialization fails,
  1793. ** then the return value from sqlite3_complete16() will be non-zero
  1794. ** regardless of whether or not the input SQL is complete.)^
  1795. **
  1796. ** The input to [sqlite3_complete()] must be a zero-terminated
  1797. ** UTF-8 string.
  1798. **
  1799. ** The input to [sqlite3_complete16()] must be a zero-terminated
  1800. ** UTF-16 string in native byte order.
  1801. */
  1802. SQLITE_API int sqlite3_complete(const char *sql);
  1803. SQLITE_API int sqlite3_complete16(const void *sql);
  1804. /*
  1805. ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
  1806. **
  1807. ** ^This routine sets a callback function that might be invoked whenever
  1808. ** an attempt is made to open a database table that another thread
  1809. ** or process has locked.
  1810. **
  1811. ** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]
  1812. ** is returned immediately upon encountering the lock. ^If the busy callback
  1813. ** is not NULL, then the callback might be invoked with two arguments.
  1814. **
  1815. ** ^The first argument to the busy handler is a copy of the void* pointer which
  1816. ** is the third argument to sqlite3_busy_handler(). ^The second argument to
  1817. ** the busy handler callback is the number of times that the busy handler has
  1818. ** been invoked for this locking event. ^If the
  1819. ** busy callback returns 0, then no additional attempts are made to
  1820. ** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned.
  1821. ** ^If the callback returns non-zero, then another attempt
  1822. ** is made to open the database for reading and the cycle repeats.
  1823. **
  1824. ** The presence of a busy handler does not guarantee that it will be invoked
  1825. ** when there is lock contention. ^If SQLite determines that invoking the busy
  1826. ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
  1827. ** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler.
  1828. ** Consider a scenario where one process is holding a read lock that
  1829. ** it is trying to promote to a reserved lock and
  1830. ** a second process is holding a reserved lock that it is trying
  1831. ** to promote to an exclusive lock. The first process cannot proceed
  1832. ** because it is blocked by the second and the second process cannot
  1833. ** proceed because it is blocked by the first. If both processes
  1834. ** invoke the busy handlers, neither will make any progress. Therefore,
  1835. ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
  1836. ** will induce the first process to release its read lock and allow
  1837. ** the second process to proceed.
  1838. **
  1839. ** ^The default busy callback is NULL.
  1840. **
  1841. ** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED]
  1842. ** when SQLite is in the middle of a large transaction where all the
  1843. ** changes will not fit into the in-memory cache. SQLite will
  1844. ** already hold a RESERVED lock on the database file, but it needs
  1845. ** to promote this lock to EXCLUSIVE so that it can spill cache
  1846. ** pages into the database file without harm to concurrent
  1847. ** readers. ^If it is unable to promote the lock, then the in-memory
  1848. ** cache will be left in an inconsistent state and so the error
  1849. ** code is promoted from the relatively benign [SQLITE_BUSY] to
  1850. ** the more severe [SQLITE_IOERR_BLOCKED]. ^This error code promotion
  1851. ** forces an automatic rollback of the changes. See the
  1852. ** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError">
  1853. ** CorruptionFollowingBusyError</a> wiki page for a discussion of why
  1854. ** this is important.
  1855. **
  1856. ** ^(There can only be a single busy handler defined for each
  1857. ** [database connection]. Setting a new busy handler clears any
  1858. ** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()]
  1859. ** will also set or clear the busy handler.
  1860. **
  1861. ** The busy callback should not take any actions which modify the
  1862. ** database connection that invoked the busy handler. Any such actions
  1863. ** result in undefined behavior.
  1864. **
  1865. ** A busy handler must not close the database connection
  1866. ** or [prepared statement] that invoked the busy handler.
  1867. */
  1868. SQLITE_API int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*);
  1869. /*
  1870. ** CAPI3REF: Set A Busy Timeout
  1871. **
  1872. ** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
  1873. ** for a specified amount of time when a table is locked. ^The handler
  1874. ** will sleep multiple times until at least "ms" milliseconds of sleeping
  1875. ** have accumulated. ^After at least "ms" milliseconds of sleeping,
  1876. ** the handler returns 0 which causes [sqlite3_step()] to return
  1877. ** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED].
  1878. **
  1879. ** ^Calling this routine with an argument less than or equal to zero
  1880. ** turns off all busy handlers.
  1881. **
  1882. ** ^(There can only be a single busy handler for a particular
  1883. ** [database connection] any any given moment. If another busy handler
  1884. ** was defined (using [sqlite3_busy_handler()]) prior to calling
  1885. ** this routine, that other busy handler is cleared.)^
  1886. */
  1887. SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms);
  1888. /*
  1889. ** CAPI3REF: Convenience Routines For Running Queries
  1890. **
  1891. ** This is a legacy interface that is preserved for backwards compatibility.
  1892. ** Use of this interface is not recommended.
  1893. **
  1894. ** Definition: A <b>result table</b> is memory data structure created by the
  1895. ** [sqlite3_get_table()] interface. A result table records the
  1896. ** complete query results from one or more queries.
  1897. **
  1898. ** The table conceptually has a number of rows and columns. But
  1899. ** these numbers are not part of the result table itself. These
  1900. ** numbers are obtained separately. Let N be the number of rows
  1901. ** and M be the number of columns.
  1902. **
  1903. ** A result table is an array of pointers to zero-terminated UTF-8 strings.
  1904. ** There are (N+1)*M elements in the array. The first M pointers point
  1905. ** to zero-terminated strings that contain the names of the columns.
  1906. ** The remaining entries all point to query results. NULL values result
  1907. ** in NULL pointers. All other values are in their UTF-8 zero-terminated
  1908. ** string representation as returned by [sqlite3_column_text()].
  1909. **
  1910. ** A result table might consist of one or more memory allocations.
  1911. ** It is not safe to pass a result table directly to [sqlite3_free()].
  1912. ** A result table should be deallocated using [sqlite3_free_table()].
  1913. **
  1914. ** ^(As an example of the result table format, suppose a query result
  1915. ** is as follows:
  1916. **
  1917. ** <blockquote><pre>
  1918. ** Name | Age
  1919. ** -----------------------
  1920. ** Alice | 43
  1921. ** Bob | 28
  1922. ** Cindy | 21
  1923. ** </pre></blockquote>
  1924. **
  1925. ** There are two column (M==2) and three rows (N==3). Thus the
  1926. ** result table has 8 entries. Suppose the result table is stored
  1927. ** in an array names azResult. Then azResult holds this content:
  1928. **
  1929. ** <blockquote><pre>
  1930. ** azResult&#91;0] = "Name";
  1931. ** azResult&#91;1] = "Age";
  1932. ** azResult&#91;2] = "Alice";
  1933. ** azResult&#91;3] = "43";
  1934. ** azResult&#91;4] = "Bob";
  1935. ** azResult&#91;5] = "28";
  1936. ** azResult&#91;6] = "Cindy";
  1937. ** azResult&#91;7] = "21";
  1938. ** </pre></blockquote>)^
  1939. **
  1940. ** ^The sqlite3_get_table() function evaluates one or more
  1941. ** semicolon-separated SQL statements in the zero-terminated UTF-8
  1942. ** string of its 2nd parameter and returns a result table to the
  1943. ** pointer given in its 3rd parameter.
  1944. **
  1945. ** After the application has finished with the result from sqlite3_get_table(),
  1946. ** it must pass the result table pointer to sqlite3_free_table() in order to
  1947. ** release the memory that was malloced. Because of the way the
  1948. ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
  1949. ** function must not try to call [sqlite3_free()] directly. Only
  1950. ** [sqlite3_free_table()] is able to release the memory properly and safely.
  1951. **
  1952. ** The sqlite3_get_table() interface is implemented as a wrapper around
  1953. ** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access
  1954. ** to any internal data structures of SQLite. It uses only the public
  1955. ** interface defined here. As a consequence, errors that occur in the
  1956. ** wrapper layer outside of the internal [sqlite3_exec()] call are not
  1957. ** reflected in subsequent calls to [sqlite3_errcode()] or
  1958. ** [sqlite3_errmsg()].
  1959. */
  1960. SQLITE_API int sqlite3_get_table(
  1961. sqlite3 *db, /* An open database */
  1962. const char *zSql, /* SQL to be evaluated */
  1963. char ***pazResult, /* Results of the query */
  1964. int *pnRow, /* Number of result rows written here */
  1965. int *pnColumn, /* Number of result columns written here */
  1966. char **pzErrmsg /* Error msg written here */
  1967. );
  1968. SQLITE_API void sqlite3_free_table(char **result);
  1969. /*
  1970. ** CAPI3REF: Formatted String Printing Functions
  1971. **
  1972. ** These routines are work-alikes of the "printf()" family of functions
  1973. ** from the standard C library.
  1974. **
  1975. ** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
  1976. ** results into memory obtained from [sqlite3_malloc()].
  1977. ** The strings returned by these two routines should be
  1978. ** released by [sqlite3_free()]. ^Both routines return a
  1979. ** NULL pointer if [sqlite3_malloc()] is unable to allocate enough
  1980. ** memory to hold the resulting string.
  1981. **
  1982. ** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
  1983. ** the standard C library. The result is written into the
  1984. ** buffer supplied as the second parameter whose size is given by
  1985. ** the first parameter. Note that the order of the
  1986. ** first two parameters is reversed from snprintf().)^ This is an
  1987. ** historical accident that cannot be fixed without breaking
  1988. ** backwards compatibility. ^(Note also that sqlite3_snprintf()
  1989. ** returns a pointer to its buffer instead of the number of
  1990. ** characters actually written into the buffer.)^ We admit that
  1991. ** the number of characters written would be a more useful return
  1992. ** value but we cannot change the implementation of sqlite3_snprintf()
  1993. ** now without breaking compatibility.
  1994. **
  1995. ** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
  1996. ** guarantees that the buffer is always zero-terminated. ^The first
  1997. ** parameter "n" is the total size of the buffer, including space for
  1998. ** the zero terminator. So the longest string that can be completely
  1999. ** written will be n-1 characters.
  2000. **
  2001. ** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
  2002. **
  2003. ** These routines all implement some additional formatting
  2004. ** options that are useful for constructing SQL statements.
  2005. ** All of the usual printf() formatting options apply. In addition, there
  2006. ** is are "%q", "%Q", and "%z" options.
  2007. **
  2008. ** ^(The %q option works like %s in that it substitutes a nul-terminated
  2009. ** string from the argument list. But %q also doubles every '\'' character.
  2010. ** %q is designed for use inside a string literal.)^ By doubling each '\''
  2011. ** character it escapes that character and allows it to be inserted into
  2012. ** the string.
  2013. **
  2014. ** For example, assume the string variable zText contains text as follows:
  2015. **
  2016. ** <blockquote><pre>
  2017. ** char *zText = "It's a happy day!";
  2018. ** </pre></blockquote>
  2019. **
  2020. ** One can use this text in an SQL statement as follows:
  2021. **
  2022. ** <blockquote><pre>
  2023. ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText);
  2024. ** sqlite3_exec(db, zSQL, 0, 0, 0);
  2025. ** sqlite3_free(zSQL);
  2026. ** </pre></blockquote>
  2027. **
  2028. ** Because the %q format string is used, the '\'' character in zText
  2029. ** is escaped and the SQL generated is as follows:
  2030. **
  2031. ** <blockquote><pre>
  2032. ** INSERT INTO table1 VALUES('It''s a happy day!')
  2033. ** </pre></blockquote>
  2034. **
  2035. ** This is correct. Had we used %s instead of %q, the generated SQL
  2036. ** would have looked like this:
  2037. **
  2038. ** <blockquote><pre>
  2039. ** INSERT INTO table1 VALUES('It's a happy day!');
  2040. ** </pre></blockquote>
  2041. **
  2042. ** This second example is an SQL syntax error. As a general rule you should
  2043. ** always use %q instead of %s when inserting text into a string literal.
  2044. **
  2045. ** ^(The %Q option works like %q except it also adds single quotes around
  2046. ** the outside of the total string. Additionally, if the parameter in the
  2047. ** argument list is a NULL pointer, %Q substitutes the text "NULL" (without
  2048. ** single quotes).)^ So, for example, one could say:
  2049. **
  2050. ** <blockquote><pre>
  2051. ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText);
  2052. ** sqlite3_exec(db, zSQL, 0, 0, 0);
  2053. ** sqlite3_free(zSQL);
  2054. ** </pre></blockquote>
  2055. **
  2056. ** The code above will render a correct SQL statement in the zSQL
  2057. ** variable even if the zText variable is a NULL pointer.
  2058. **
  2059. ** ^(The "%z" formatting option works like "%s" but with the
  2060. ** addition that after the string has been read and copied into
  2061. ** the result, [sqlite3_free()] is called on the input string.)^
  2062. */
  2063. SQLITE_API char *sqlite3_mprintf(const char*,...);
  2064. SQLITE_API char *sqlite3_vmprintf(const char*, va_list);
  2065. SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...);
  2066. SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list);
  2067. /*
  2068. ** CAPI3REF: Memory Allocation Subsystem
  2069. **
  2070. ** The SQLite core uses these three routines for all of its own
  2071. ** internal memory allocation needs. "Core" in the previous sentence
  2072. ** does not include operating-system specific VFS implementation. The
  2073. ** Windows VFS uses native malloc() and free() for some operations.
  2074. **
  2075. ** ^The sqlite3_malloc() routine returns a pointer to a block
  2076. ** of memory at least N bytes in length, where N is the parameter.
  2077. ** ^If sqlite3_malloc() is unable to obtain sufficient free
  2078. ** memory, it returns a NULL pointer. ^If the parameter N to
  2079. ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
  2080. ** a NULL pointer.
  2081. **
  2082. ** ^Calling sqlite3_free() with a pointer previously returned
  2083. ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
  2084. ** that it might be reused. ^The sqlite3_free() routine is
  2085. ** a no-op if is called with a NULL pointer. Passing a NULL pointer
  2086. ** to sqlite3_free() is harmless. After being freed, memory
  2087. ** should neither be read nor written. Even reading previously freed
  2088. ** memory might result in a segmentation fault or other severe error.
  2089. ** Memory corruption, a segmentation fault, or other severe error
  2090. ** might result if sqlite3_free() is called with a non-NULL pointer that
  2091. ** was not obtained from sqlite3_malloc() or sqlite3_realloc().
  2092. **
  2093. ** ^(The sqlite3_realloc() interface attempts to resize a
  2094. ** prior memory allocation to be at least N bytes, where N is the
  2095. ** second parameter. The memory allocation to be resized is the first
  2096. ** parameter.)^ ^ If the first parameter to sqlite3_realloc()
  2097. ** is a NULL pointer then its behavior is identical to calling
  2098. ** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc().
  2099. ** ^If the second parameter to sqlite3_realloc() is zero or
  2100. ** negative then the behavior is exactly the same as calling
  2101. ** sqlite3_free(P) where P is the first parameter to sqlite3_realloc().
  2102. ** ^sqlite3_realloc() returns a pointer to a memory allocation
  2103. ** of at least N bytes in size or NULL if sufficient memory is unavailable.
  2104. ** ^If M is the size of the prior allocation, then min(N,M) bytes
  2105. ** of the prior allocation are copied into the beginning of buffer returned
  2106. ** by sqlite3_realloc() and the prior allocation is freed.
  2107. ** ^If sqlite3_realloc() returns NULL, then the prior allocation
  2108. ** is not freed.
  2109. **
  2110. ** ^The memory returned by sqlite3_malloc() and sqlite3_realloc()
  2111. ** is always aligned to at least an 8 byte boundary, or to a
  2112. ** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
  2113. ** option is used.
  2114. **
  2115. ** In SQLite version 3.5.0 and 3.5.1, it was possible to define
  2116. ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in
  2117. ** implementation of these routines to be omitted. That capability
  2118. ** is no longer provided. Only built-in memory allocators can be used.
  2119. **
  2120. ** The Windows OS interface layer calls
  2121. ** the system malloc() and free() directly when converting
  2122. ** filenames between the UTF-8 encoding used by SQLite
  2123. ** and whatever filename encoding is used by the particular Windows
  2124. ** installation. Memory allocation errors are detected, but
  2125. ** they are reported back as [SQLITE_CANTOPEN] or
  2126. ** [SQLITE_IOERR] rather than [SQLITE_NOMEM].
  2127. **
  2128. ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
  2129. ** must be either NULL or else pointers obtained from a prior
  2130. ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
  2131. ** not yet been released.
  2132. **
  2133. ** The application must not read or write any part of
  2134. ** a block of memory after it has been released using
  2135. ** [sqlite3_free()] or [sqlite3_realloc()].
  2136. */
  2137. SQLITE_API void *sqlite3_malloc(int);
  2138. SQLITE_API void *sqlite3_realloc(void*, int);
  2139. SQLITE_API void sqlite3_free(void*);
  2140. /*
  2141. ** CAPI3REF: Memory Allocator Statistics
  2142. **
  2143. ** SQLite provides these two interfaces for reporting on the status
  2144. ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
  2145. ** routines, which form the built-in memory allocation subsystem.
  2146. **
  2147. ** ^The [sqlite3_memory_used()] routine returns the number of bytes
  2148. ** of memory currently outstanding (malloced but not freed).
  2149. ** ^The [sqlite3_memory_highwater()] routine returns the maximum
  2150. ** value of [sqlite3_memory_used()] since the high-water mark
  2151. ** was last reset. ^The values returned by [sqlite3_memory_used()] and
  2152. ** [sqlite3_memory_highwater()] include any overhead
  2153. ** added by SQLite in its implementation of [sqlite3_malloc()],
  2154. ** but not overhead added by the any underlying system library
  2155. ** routines that [sqlite3_malloc()] may call.
  2156. **
  2157. ** ^The memory high-water mark is reset to the current value of
  2158. ** [sqlite3_memory_used()] if and only if the parameter to
  2159. ** [sqlite3_memory_highwater()] is true. ^The value returned
  2160. ** by [sqlite3_memory_highwater(1)] is the high-water mark
  2161. ** prior to the reset.
  2162. */
  2163. SQLITE_API sqlite3_int64 sqlite3_memory_used(void);
  2164. SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
  2165. /*
  2166. ** CAPI3REF: Pseudo-Random Number Generator
  2167. **
  2168. ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
  2169. ** select random [ROWID | ROWIDs] when inserting new records into a table that
  2170. ** already uses the largest possible [ROWID]. The PRNG is also used for
  2171. ** the build-in random() and randomblob() SQL functions. This interface allows
  2172. ** applications to access the same PRNG for other purposes.
  2173. **
  2174. ** ^A call to this routine stores N bytes of randomness into buffer P.
  2175. **
  2176. ** ^The first time this routine is invoked (either internally or by
  2177. ** the application) the PRNG is seeded using randomness obtained
  2178. ** from the xRandomness method of the default [sqlite3_vfs] object.
  2179. ** ^On all subsequent invocations, the pseudo-randomness is generated
  2180. ** internally and without recourse to the [sqlite3_vfs] xRandomness
  2181. ** method.
  2182. */
  2183. SQLITE_API void sqlite3_randomness(int N, void *P);
  2184. /*
  2185. ** CAPI3REF: Compile-Time Authorization Callbacks
  2186. **
  2187. ** ^This routine registers an authorizer callback with a particular
  2188. ** [database connection], supplied in the first argument.
  2189. ** ^The authorizer callback is invoked as SQL statements are being compiled
  2190. ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
  2191. ** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various
  2192. ** points during the compilation process, as logic is being created
  2193. ** to perform various actions, the authorizer callback is invoked to
  2194. ** see if those actions are allowed. ^The authorizer callback should
  2195. ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
  2196. ** specific action but allow the SQL statement to continue to be
  2197. ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
  2198. ** rejected with an error. ^If the authorizer callback returns
  2199. ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
  2200. ** then the [sqlite3_prepare_v2()] or equivalent call that triggered
  2201. ** the authorizer will fail with an error message.
  2202. **
  2203. ** When the callback returns [SQLITE_OK], that means the operation
  2204. ** requested is ok. ^When the callback returns [SQLITE_DENY], the
  2205. ** [sqlite3_prepare_v2()] or equivalent call that triggered the
  2206. ** authorizer will fail with an error message explaining that
  2207. ** access is denied.
  2208. **
  2209. ** ^The first parameter to the authorizer callback is a copy of the third
  2210. ** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
  2211. ** to the callback is an integer [SQLITE_COPY | action code] that specifies
  2212. ** the particular action to be authorized. ^The third through sixth parameters
  2213. ** to the callback are zero-terminated strings that contain additional
  2214. ** details about the action to be authorized.
  2215. **
  2216. ** ^If the action code is [SQLITE_READ]
  2217. ** and the callback returns [SQLITE_IGNORE] then the
  2218. ** [prepared statement] statement is constructed to substitute
  2219. ** a NULL value in place of the table column that would have
  2220. ** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE]
  2221. ** return can be used to deny an untrusted user access to individual
  2222. ** columns of a table.
  2223. ** ^If the action code is [SQLITE_DELETE] and the callback returns
  2224. ** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
  2225. ** [truncate optimization] is disabled and all rows are deleted individually.
  2226. **
  2227. ** An authorizer is used when [sqlite3_prepare | preparing]
  2228. ** SQL statements from an untrusted source, to ensure that the SQL statements
  2229. ** do not try to access data they are not allowed to see, or that they do not
  2230. ** try to execute malicious statements that damage the database. For
  2231. ** example, an application may allow a user to enter arbitrary
  2232. ** SQL queries for evaluation by a database. But the application does
  2233. ** not want the user to be able to make arbitrary changes to the
  2234. ** database. An authorizer could then be put in place while the
  2235. ** user-entered SQL is being [sqlite3_prepare | prepared] that
  2236. ** disallows everything except [SELECT] statements.
  2237. **
  2238. ** Applications that need to process SQL from untrusted sources
  2239. ** might also consider lowering resource limits using [sqlite3_limit()]
  2240. ** and limiting database size using the [max_page_count] [PRAGMA]
  2241. ** in addition to using an authorizer.
  2242. **
  2243. ** ^(Only a single authorizer can be in place on a database connection
  2244. ** at a time. Each call to sqlite3_set_authorizer overrides the
  2245. ** previous call.)^ ^Disable the authorizer by installing a NULL callback.
  2246. ** The authorizer is disabled by default.
  2247. **
  2248. ** The authorizer callback must not do anything that will modify
  2249. ** the database connection that invoked the authorizer callback.
  2250. ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
  2251. ** database connections for the meaning of "modify" in this paragraph.
  2252. **
  2253. ** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
  2254. ** statement might be re-prepared during [sqlite3_step()] due to a
  2255. ** schema change. Hence, the application should ensure that the
  2256. ** correct authorizer callback remains in place during the [sqlite3_step()].
  2257. **
  2258. ** ^Note that the authorizer callback is invoked only during
  2259. ** [sqlite3_prepare()] or its variants. Authorization is not
  2260. ** performed during statement evaluation in [sqlite3_step()], unless
  2261. ** as stated in the previous paragraph, sqlite3_step() invokes
  2262. ** sqlite3_prepare_v2() to reprepare a statement after a schema change.
  2263. */
  2264. SQLITE_API int sqlite3_set_authorizer(
  2265. sqlite3*,
  2266. int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
  2267. void *pUserData
  2268. );
  2269. /*
  2270. ** CAPI3REF: Authorizer Return Codes
  2271. **
  2272. ** The [sqlite3_set_authorizer | authorizer callback function] must
  2273. ** return either [SQLITE_OK] or one of these two constants in order
  2274. ** to signal SQLite whether or not the action is permitted. See the
  2275. ** [sqlite3_set_authorizer | authorizer documentation] for additional
  2276. ** information.
  2277. **
  2278. ** Note that SQLITE_IGNORE is also used as a [SQLITE_ROLLBACK | return code]
  2279. ** from the [sqlite3_vtab_on_conflict()] interface.
  2280. */
  2281. #define SQLITE_DENY 1 /* Abort the SQL statement with an error */
  2282. #define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */
  2283. /*
  2284. ** CAPI3REF: Authorizer Action Codes
  2285. **
  2286. ** The [sqlite3_set_authorizer()] interface registers a callback function
  2287. ** that is invoked to authorize certain SQL statement actions. The
  2288. ** second parameter to the callback is an integer code that specifies
  2289. ** what action is being authorized. These are the integer action codes that
  2290. ** the authorizer callback may be passed.
  2291. **
  2292. ** These action code values signify what kind of operation is to be
  2293. ** authorized. The 3rd and 4th parameters to the authorization
  2294. ** callback function will be parameters or NULL depending on which of these
  2295. ** codes is used as the second parameter. ^(The 5th parameter to the
  2296. ** authorizer callback is the name of the database ("main", "temp",
  2297. ** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback
  2298. ** is the name of the inner-most trigger or view that is responsible for
  2299. ** the access attempt or NULL if this access attempt is directly from
  2300. ** top-level SQL code.
  2301. */
  2302. /******************************************* 3rd ************ 4th ***********/
  2303. #define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */
  2304. #define SQLITE_CREATE_TABLE 2 /* Table Name NULL */
  2305. #define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */
  2306. #define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */
  2307. #define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */
  2308. #define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */
  2309. #define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */
  2310. #define SQLITE_CREATE_VIEW 8 /* View Name NULL */
  2311. #define SQLITE_DELETE 9 /* Table Name NULL */
  2312. #define SQLITE_DROP_INDEX 10 /* Index Name Table Name */
  2313. #define SQLITE_DROP_TABLE 11 /* Table Name NULL */
  2314. #define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */
  2315. #define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */
  2316. #define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */
  2317. #define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */
  2318. #define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */
  2319. #define SQLITE_DROP_VIEW 17 /* View Name NULL */
  2320. #define SQLITE_INSERT 18 /* Table Name NULL */
  2321. #define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */
  2322. #define SQLITE_READ 20 /* Table Name Column Name */
  2323. #define SQLITE_SELECT 21 /* NULL NULL */
  2324. #define SQLITE_TRANSACTION 22 /* Operation NULL */
  2325. #define SQLITE_UPDATE 23 /* Table Name Column Name */
  2326. #define SQLITE_ATTACH 24 /* Filename NULL */
  2327. #define SQLITE_DETACH 25 /* Database Name NULL */
  2328. #define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */
  2329. #define SQLITE_REINDEX 27 /* Index Name NULL */
  2330. #define SQLITE_ANALYZE 28 /* Table Name NULL */
  2331. #define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */
  2332. #define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */
  2333. #define SQLITE_FUNCTION 31 /* NULL Function Name */
  2334. #define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */
  2335. #define SQLITE_COPY 0 /* No longer used */
  2336. /*
  2337. ** CAPI3REF: Tracing And Profiling Functions
  2338. **
  2339. ** These routines register callback functions that can be used for
  2340. ** tracing and profiling the execution of SQL statements.
  2341. **
  2342. ** ^The callback function registered by sqlite3_trace() is invoked at
  2343. ** various times when an SQL statement is being run by [sqlite3_step()].
  2344. ** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
  2345. ** SQL statement text as the statement first begins executing.
  2346. ** ^(Additional sqlite3_trace() callbacks might occur
  2347. ** as each triggered subprogram is entered. The callbacks for triggers
  2348. ** contain a UTF-8 SQL comment that identifies the trigger.)^
  2349. **
  2350. ** ^The callback function registered by sqlite3_profile() is invoked
  2351. ** as each SQL statement finishes. ^The profile callback contains
  2352. ** the original statement text and an estimate of wall-clock time
  2353. ** of how long that statement took to run. ^The profile callback
  2354. ** time is in units of nanoseconds, however the current implementation
  2355. ** is only capable of millisecond resolution so the six least significant
  2356. ** digits in the time are meaningless. Future versions of SQLite
  2357. ** might provide greater resolution on the profiler callback. The
  2358. ** sqlite3_profile() function is considered experimental and is
  2359. ** subject to change in future versions of SQLite.
  2360. */
  2361. SQLITE_API void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*);
  2362. SQLITE_API SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*,
  2363. void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
  2364. /*
  2365. ** CAPI3REF: Query Progress Callbacks
  2366. **
  2367. ** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
  2368. ** function X to be invoked periodically during long running calls to
  2369. ** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for
  2370. ** database connection D. An example use for this
  2371. ** interface is to keep a GUI updated during a large query.
  2372. **
  2373. ** ^The parameter P is passed through as the only parameter to the
  2374. ** callback function X. ^The parameter N is the number of
  2375. ** [virtual machine instructions] that are evaluated between successive
  2376. ** invocations of the callback X.
  2377. **
  2378. ** ^Only a single progress handler may be defined at one time per
  2379. ** [database connection]; setting a new progress handler cancels the
  2380. ** old one. ^Setting parameter X to NULL disables the progress handler.
  2381. ** ^The progress handler is also disabled by setting N to a value less
  2382. ** than 1.
  2383. **
  2384. ** ^If the progress callback returns non-zero, the operation is
  2385. ** interrupted. This feature can be used to implement a
  2386. ** "Cancel" button on a GUI progress dialog box.
  2387. **
  2388. ** The progress handler callback must not do anything that will modify
  2389. ** the database connection that invoked the progress handler.
  2390. ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
  2391. ** database connections for the meaning of "modify" in this paragraph.
  2392. **
  2393. */
  2394. SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
  2395. /*
  2396. ** CAPI3REF: Opening A New Database Connection
  2397. **
  2398. ** ^These routines open an SQLite database file as specified by the
  2399. ** filename argument. ^The filename argument is interpreted as UTF-8 for
  2400. ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
  2401. ** order for sqlite3_open16(). ^(A [database connection] handle is usually
  2402. ** returned in *ppDb, even if an error occurs. The only exception is that
  2403. ** if SQLite is unable to allocate memory to hold the [sqlite3] object,
  2404. ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
  2405. ** object.)^ ^(If the database is opened (and/or created) successfully, then
  2406. ** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The
  2407. ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
  2408. ** an English language description of the error following a failure of any
  2409. ** of the sqlite3_open() routines.
  2410. **
  2411. ** ^The default encoding for the database will be UTF-8 if
  2412. ** sqlite3_open() or sqlite3_open_v2() is called and
  2413. ** UTF-16 in the native byte order if sqlite3_open16() is used.
  2414. **
  2415. ** Whether or not an error occurs when it is opened, resources
  2416. ** associated with the [database connection] handle should be released by
  2417. ** passing it to [sqlite3_close()] when it is no longer required.
  2418. **
  2419. ** The sqlite3_open_v2() interface works like sqlite3_open()
  2420. ** except that it accepts two additional parameters for additional control
  2421. ** over the new database connection. ^(The flags parameter to
  2422. ** sqlite3_open_v2() can take one of
  2423. ** the following three values, optionally combined with the
  2424. ** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE],
  2425. ** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^
  2426. **
  2427. ** <dl>
  2428. ** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
  2429. ** <dd>The database is opened in read-only mode. If the database does not
  2430. ** already exist, an error is returned.</dd>)^
  2431. **
  2432. ** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
  2433. ** <dd>The database is opened for reading and writing if possible, or reading
  2434. ** only if the file is write protected by the operating system. In either
  2435. ** case the database must already exist, otherwise an error is returned.</dd>)^
  2436. **
  2437. ** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
  2438. ** <dd>The database is opened for reading and writing, and is created if
  2439. ** it does not already exist. This is the behavior that is always used for
  2440. ** sqlite3_open() and sqlite3_open16().</dd>)^
  2441. ** </dl>
  2442. **
  2443. ** If the 3rd parameter to sqlite3_open_v2() is not one of the
  2444. ** combinations shown above optionally combined with other
  2445. ** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits]
  2446. ** then the behavior is undefined.
  2447. **
  2448. ** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection
  2449. ** opens in the multi-thread [threading mode] as long as the single-thread
  2450. ** mode has not been set at compile-time or start-time. ^If the
  2451. ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens
  2452. ** in the serialized [threading mode] unless single-thread was
  2453. ** previously selected at compile-time or start-time.
  2454. ** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be
  2455. ** eligible to use [shared cache mode], regardless of whether or not shared
  2456. ** cache is enabled using [sqlite3_enable_shared_cache()]. ^The
  2457. ** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not
  2458. ** participate in [shared cache mode] even if it is enabled.
  2459. **
  2460. ** ^The fourth parameter to sqlite3_open_v2() is the name of the
  2461. ** [sqlite3_vfs] object that defines the operating system interface that
  2462. ** the new database connection should use. ^If the fourth parameter is
  2463. ** a NULL pointer then the default [sqlite3_vfs] object is used.
  2464. **
  2465. ** ^If the filename is ":memory:", then a private, temporary in-memory database
  2466. ** is created for the connection. ^This in-memory database will vanish when
  2467. ** the database connection is closed. Future versions of SQLite might
  2468. ** make use of additional special filenames that begin with the ":" character.
  2469. ** It is recommended that when a database filename actually does begin with
  2470. ** a ":" character you should prefix the filename with a pathname such as
  2471. ** "./" to avoid ambiguity.
  2472. **
  2473. ** ^If the filename is an empty string, then a private, temporary
  2474. ** on-disk database will be created. ^This private database will be
  2475. ** automatically deleted as soon as the database connection is closed.
  2476. **
  2477. ** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
  2478. **
  2479. ** ^If [URI filename] interpretation is enabled, and the filename argument
  2480. ** begins with "file:", then the filename is interpreted as a URI. ^URI
  2481. ** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
  2482. ** set in the fourth argument to sqlite3_open_v2(), or if it has
  2483. ** been enabled globally using the [SQLITE_CONFIG_URI] option with the
  2484. ** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
  2485. ** As of SQLite version 3.7.7, URI filename interpretation is turned off
  2486. ** by default, but future releases of SQLite might enable URI filename
  2487. ** interpretation by default. See "[URI filenames]" for additional
  2488. ** information.
  2489. **
  2490. ** URI filenames are parsed according to RFC 3986. ^If the URI contains an
  2491. ** authority, then it must be either an empty string or the string
  2492. ** "localhost". ^If the authority is not an empty string or "localhost", an
  2493. ** error is returned to the caller. ^The fragment component of a URI, if
  2494. ** present, is ignored.
  2495. **
  2496. ** ^SQLite uses the path component of the URI as the name of the disk file
  2497. ** which contains the database. ^If the path begins with a '/' character,
  2498. ** then it is interpreted as an absolute path. ^If the path does not begin
  2499. ** with a '/' (meaning that the authority section is omitted from the URI)
  2500. ** then the path is interpreted as a relative path.
  2501. ** ^On windows, the first component of an absolute path
  2502. ** is a drive specification (e.g. "C:").
  2503. **
  2504. ** [[core URI query parameters]]
  2505. ** The query component of a URI may contain parameters that are interpreted
  2506. ** either by SQLite itself, or by a [VFS | custom VFS implementation].
  2507. ** SQLite interprets the following three query parameters:
  2508. **
  2509. ** <ul>
  2510. ** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
  2511. ** a VFS object that provides the operating system interface that should
  2512. ** be used to access the database file on disk. ^If this option is set to
  2513. ** an empty string the default VFS object is used. ^Specifying an unknown
  2514. ** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
  2515. ** present, then the VFS specified by the option takes precedence over
  2516. ** the value passed as the fourth parameter to sqlite3_open_v2().
  2517. **
  2518. ** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw" or
  2519. ** "rwc". Attempting to set it to any other value is an error)^.
  2520. ** ^If "ro" is specified, then the database is opened for read-only
  2521. ** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the
  2522. ** third argument to sqlite3_prepare_v2(). ^If the mode option is set to
  2523. ** "rw", then the database is opened for read-write (but not create)
  2524. ** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had
  2525. ** been set. ^Value "rwc" is equivalent to setting both
  2526. ** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If sqlite3_open_v2() is
  2527. ** used, it is an error to specify a value for the mode parameter that is
  2528. ** less restrictive than that specified by the flags passed as the third
  2529. ** parameter.
  2530. **
  2531. ** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
  2532. ** "private". ^Setting it to "shared" is equivalent to setting the
  2533. ** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
  2534. ** sqlite3_open_v2(). ^Setting the cache parameter to "private" is
  2535. ** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
  2536. ** ^If sqlite3_open_v2() is used and the "cache" parameter is present in
  2537. ** a URI filename, its value overrides any behaviour requested by setting
  2538. ** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.
  2539. ** </ul>
  2540. **
  2541. ** ^Specifying an unknown parameter in the query component of a URI is not an
  2542. ** error. Future versions of SQLite might understand additional query
  2543. ** parameters. See "[query parameters with special meaning to SQLite]" for
  2544. ** additional information.
  2545. **
  2546. ** [[URI filename examples]] <h3>URI filename examples</h3>
  2547. **
  2548. ** <table border="1" align=center cellpadding=5>
  2549. ** <tr><th> URI filenames <th> Results
  2550. ** <tr><td> file:data.db <td>
  2551. ** Open the file "data.db" in the current directory.
  2552. ** <tr><td> file:/home/fred/data.db<br>
  2553. ** file:///home/fred/data.db <br>
  2554. ** file://localhost/home/fred/data.db <br> <td>
  2555. ** Open the database file "/home/fred/data.db".
  2556. ** <tr><td> file://darkstar/home/fred/data.db <td>
  2557. ** An error. "darkstar" is not a recognized authority.
  2558. ** <tr><td style="white-space:nowrap">
  2559. ** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
  2560. ** <td> Windows only: Open the file "data.db" on fred's desktop on drive
  2561. ** C:. Note that the %20 escaping in this example is not strictly
  2562. ** necessary - space characters can be used literally
  2563. ** in URI filenames.
  2564. ** <tr><td> file:data.db?mode=ro&cache=private <td>
  2565. ** Open file "data.db" in the current directory for read-only access.
  2566. ** Regardless of whether or not shared-cache mode is enabled by
  2567. ** default, use a private cache.
  2568. ** <tr><td> file:/home/fred/data.db?vfs=unix-nolock <td>
  2569. ** Open file "/home/fred/data.db". Use the special VFS "unix-nolock".
  2570. ** <tr><td> file:data.db?mode=readonly <td>
  2571. ** An error. "readonly" is not a valid option for the "mode" parameter.
  2572. ** </table>
  2573. **
  2574. ** ^URI hexadecimal escape sequences (%HH) are supported within the path and
  2575. ** query components of a URI. A hexadecimal escape sequence consists of a
  2576. ** percent sign - "%" - followed by exactly two hexadecimal digits
  2577. ** specifying an octet value. ^Before the path or query components of a
  2578. ** URI filename are interpreted, they are encoded using UTF-8 and all
  2579. ** hexadecimal escape sequences replaced by a single byte containing the
  2580. ** corresponding octet. If this process generates an invalid UTF-8 encoding,
  2581. ** the results are undefined.
  2582. **
  2583. ** <b>Note to Windows users:</b> The encoding used for the filename argument
  2584. ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
  2585. ** codepage is currently defined. Filenames containing international
  2586. ** characters must be converted to UTF-8 prior to passing them into
  2587. ** sqlite3_open() or sqlite3_open_v2().
  2588. */
  2589. SQLITE_API int sqlite3_open(
  2590. const char *filename, /* Database filename (UTF-8) */
  2591. sqlite3 **ppDb /* OUT: SQLite db handle */
  2592. );
  2593. SQLITE_API int sqlite3_open16(
  2594. const void *filename, /* Database filename (UTF-16) */
  2595. sqlite3 **ppDb /* OUT: SQLite db handle */
  2596. );
  2597. SQLITE_API int sqlite3_open_v2(
  2598. const char *filename, /* Database filename (UTF-8) */
  2599. sqlite3 **ppDb, /* OUT: SQLite db handle */
  2600. int flags, /* Flags */
  2601. const char *zVfs /* Name of VFS module to use */
  2602. );
  2603. /*
  2604. ** CAPI3REF: Obtain Values For URI Parameters
  2605. **
  2606. ** These are utility routines, useful to VFS implementations, that check
  2607. ** to see if a database file was a URI that contained a specific query
  2608. ** parameter, and if so obtains the value of that query parameter.
  2609. **
  2610. ** If F is the database filename pointer passed into the xOpen() method of
  2611. ** a VFS implementation when the flags parameter to xOpen() has one or
  2612. ** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and
  2613. ** P is the name of the query parameter, then
  2614. ** sqlite3_uri_parameter(F,P) returns the value of the P
  2615. ** parameter if it exists or a NULL pointer if P does not appear as a
  2616. ** query parameter on F. If P is a query parameter of F
  2617. ** has no explicit value, then sqlite3_uri_parameter(F,P) returns
  2618. ** a pointer to an empty string.
  2619. **
  2620. ** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
  2621. ** parameter and returns true (1) or false (0) according to the value
  2622. ** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
  2623. ** value of query parameter P is one of "yes", "true", or "on" in any
  2624. ** case or if the value begins with a non-zero number. The
  2625. ** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
  2626. ** query parameter P is one of "no", "false", or "off" in any case or
  2627. ** if the value begins with a numeric zero. If P is not a query
  2628. ** parameter on F or if the value of P is does not match any of the
  2629. ** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).
  2630. **
  2631. ** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
  2632. ** 64-bit signed integer and returns that integer, or D if P does not
  2633. ** exist. If the value of P is something other than an integer, then
  2634. ** zero is returned.
  2635. **
  2636. ** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
  2637. ** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and
  2638. ** is not a database file pathname pointer that SQLite passed into the xOpen
  2639. ** VFS method, then the behavior of this routine is undefined and probably
  2640. ** undesirable.
  2641. */
  2642. SQLITE_API const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam);
  2643. SQLITE_API int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault);
  2644. SQLITE_API sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64);
  2645. /*
  2646. ** CAPI3REF: Error Codes And Messages
  2647. **
  2648. ** ^The sqlite3_errcode() interface returns the numeric [result code] or
  2649. ** [extended result code] for the most recent failed sqlite3_* API call
  2650. ** associated with a [database connection]. If a prior API call failed
  2651. ** but the most recent API call succeeded, the return value from
  2652. ** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode()
  2653. ** interface is the same except that it always returns the
  2654. ** [extended result code] even when extended result codes are
  2655. ** disabled.
  2656. **
  2657. ** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
  2658. ** text that describes the error, as either UTF-8 or UTF-16 respectively.
  2659. ** ^(Memory to hold the error message string is managed internally.
  2660. ** The application does not need to worry about freeing the result.
  2661. ** However, the error string might be overwritten or deallocated by
  2662. ** subsequent calls to other SQLite interface functions.)^
  2663. **
  2664. ** When the serialized [threading mode] is in use, it might be the
  2665. ** case that a second error occurs on a separate thread in between
  2666. ** the time of the first error and the call to these interfaces.
  2667. ** When that happens, the second error will be reported since these
  2668. ** interfaces always report the most recent result. To avoid
  2669. ** this, each thread can obtain exclusive use of the [database connection] D
  2670. ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
  2671. ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
  2672. ** all calls to the interfaces listed here are completed.
  2673. **
  2674. ** If an interface fails with SQLITE_MISUSE, that means the interface
  2675. ** was invoked incorrectly by the application. In that case, the
  2676. ** error code and message may or may not be set.
  2677. */
  2678. SQLITE_API int sqlite3_errcode(sqlite3 *db);
  2679. SQLITE_API int sqlite3_extended_errcode(sqlite3 *db);
  2680. SQLITE_API const char *sqlite3_errmsg(sqlite3*);
  2681. SQLITE_API const void *sqlite3_errmsg16(sqlite3*);
  2682. /*
  2683. ** CAPI3REF: SQL Statement Object
  2684. ** KEYWORDS: {prepared statement} {prepared statements}
  2685. **
  2686. ** An instance of this object represents a single SQL statement.
  2687. ** This object is variously known as a "prepared statement" or a
  2688. ** "compiled SQL statement" or simply as a "statement".
  2689. **
  2690. ** The life of a statement object goes something like this:
  2691. **
  2692. ** <ol>
  2693. ** <li> Create the object using [sqlite3_prepare_v2()] or a related
  2694. ** function.
  2695. ** <li> Bind values to [host parameters] using the sqlite3_bind_*()
  2696. ** interfaces.
  2697. ** <li> Run the SQL by calling [sqlite3_step()] one or more times.
  2698. ** <li> Reset the statement using [sqlite3_reset()] then go back
  2699. ** to step 2. Do this zero or more times.
  2700. ** <li> Destroy the object using [sqlite3_finalize()].
  2701. ** </ol>
  2702. **
  2703. ** Refer to documentation on individual methods above for additional
  2704. ** information.
  2705. */
  2706. typedef struct sqlite3_stmt sqlite3_stmt;
  2707. /*
  2708. ** CAPI3REF: Run-time Limits
  2709. **
  2710. ** ^(This interface allows the size of various constructs to be limited
  2711. ** on a connection by connection basis. The first parameter is the
  2712. ** [database connection] whose limit is to be set or queried. The
  2713. ** second parameter is one of the [limit categories] that define a
  2714. ** class of constructs to be size limited. The third parameter is the
  2715. ** new limit for that construct.)^
  2716. **
  2717. ** ^If the new limit is a negative number, the limit is unchanged.
  2718. ** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
  2719. ** [limits | hard upper bound]
  2720. ** set at compile-time by a C preprocessor macro called
  2721. ** [limits | SQLITE_MAX_<i>NAME</i>].
  2722. ** (The "_LIMIT_" in the name is changed to "_MAX_".))^
  2723. ** ^Attempts to increase a limit above its hard upper bound are
  2724. ** silently truncated to the hard upper bound.
  2725. **
  2726. ** ^Regardless of whether or not the limit was changed, the
  2727. ** [sqlite3_limit()] interface returns the prior value of the limit.
  2728. ** ^Hence, to find the current value of a limit without changing it,
  2729. ** simply invoke this interface with the third parameter set to -1.
  2730. **
  2731. ** Run-time limits are intended for use in applications that manage
  2732. ** both their own internal database and also databases that are controlled
  2733. ** by untrusted external sources. An example application might be a
  2734. ** web browser that has its own databases for storing history and
  2735. ** separate databases controlled by JavaScript applications downloaded
  2736. ** off the Internet. The internal databases can be given the
  2737. ** large, default limits. Databases managed by external sources can
  2738. ** be given much smaller limits designed to prevent a denial of service
  2739. ** attack. Developers might also want to use the [sqlite3_set_authorizer()]
  2740. ** interface to further control untrusted SQL. The size of the database
  2741. ** created by an untrusted script can be contained using the
  2742. ** [max_page_count] [PRAGMA].
  2743. **
  2744. ** New run-time limit categories may be added in future releases.
  2745. */
  2746. SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal);
  2747. /*
  2748. ** CAPI3REF: Run-Time Limit Categories
  2749. ** KEYWORDS: {limit category} {*limit categories}
  2750. **
  2751. ** These constants define various performance limits
  2752. ** that can be lowered at run-time using [sqlite3_limit()].
  2753. ** The synopsis of the meanings of the various limits is shown below.
  2754. ** Additional information is available at [limits | Limits in SQLite].
  2755. **
  2756. ** <dl>
  2757. ** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt>
  2758. ** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
  2759. **
  2760. ** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
  2761. ** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
  2762. **
  2763. ** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt>
  2764. ** <dd>The maximum number of columns in a table definition or in the
  2765. ** result set of a [SELECT] or the maximum number of columns in an index
  2766. ** or in an ORDER BY or GROUP BY clause.</dd>)^
  2767. **
  2768. ** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
  2769. ** <dd>The maximum depth of the parse tree on any expression.</dd>)^
  2770. **
  2771. ** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
  2772. ** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
  2773. **
  2774. ** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
  2775. ** <dd>The maximum number of instructions in a virtual machine program
  2776. ** used to implement an SQL statement. This limit is not currently
  2777. ** enforced, though that might be added in some future release of
  2778. ** SQLite.</dd>)^
  2779. **
  2780. ** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
  2781. ** <dd>The maximum number of arguments on a function.</dd>)^
  2782. **
  2783. ** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
  2784. ** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
  2785. **
  2786. ** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]]
  2787. ** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
  2788. ** <dd>The maximum length of the pattern argument to the [LIKE] or
  2789. ** [GLOB] operators.</dd>)^
  2790. **
  2791. ** [[SQLITE_LIMIT_VARIABLE_NUMBER]]
  2792. ** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
  2793. ** <dd>The maximum index number of any [parameter] in an SQL statement.)^
  2794. **
  2795. ** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
  2796. ** <dd>The maximum depth of recursion for triggers.</dd>)^
  2797. ** </dl>
  2798. */
  2799. #define SQLITE_LIMIT_LENGTH 0
  2800. #define SQLITE_LIMIT_SQL_LENGTH 1
  2801. #define SQLITE_LIMIT_COLUMN 2
  2802. #define SQLITE_LIMIT_EXPR_DEPTH 3
  2803. #define SQLITE_LIMIT_COMPOUND_SELECT 4
  2804. #define SQLITE_LIMIT_VDBE_OP 5
  2805. #define SQLITE_LIMIT_FUNCTION_ARG 6
  2806. #define SQLITE_LIMIT_ATTACHED 7
  2807. #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8
  2808. #define SQLITE_LIMIT_VARIABLE_NUMBER 9
  2809. #define SQLITE_LIMIT_TRIGGER_DEPTH 10
  2810. /*
  2811. ** CAPI3REF: Compiling An SQL Statement
  2812. ** KEYWORDS: {SQL statement compiler}
  2813. **
  2814. ** To execute an SQL query, it must first be compiled into a byte-code
  2815. ** program using one of these routines.
  2816. **
  2817. ** The first argument, "db", is a [database connection] obtained from a
  2818. ** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
  2819. ** [sqlite3_open16()]. The database connection must not have been closed.
  2820. **
  2821. ** The second argument, "zSql", is the statement to be compiled, encoded
  2822. ** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2()
  2823. ** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2()
  2824. ** use UTF-16.
  2825. **
  2826. ** ^If the nByte argument is less than zero, then zSql is read up to the
  2827. ** first zero terminator. ^If nByte is non-negative, then it is the maximum
  2828. ** number of bytes read from zSql. ^When nByte is non-negative, the
  2829. ** zSql string ends at either the first '\000' or '\u0000' character or
  2830. ** the nByte-th byte, whichever comes first. If the caller knows
  2831. ** that the supplied string is nul-terminated, then there is a small
  2832. ** performance advantage to be gained by passing an nByte parameter that
  2833. ** is equal to the number of bytes in the input string <i>including</i>
  2834. ** the nul-terminator bytes as this saves SQLite from having to
  2835. ** make a copy of the input string.
  2836. **
  2837. ** ^If pzTail is not NULL then *pzTail is made to point to the first byte
  2838. ** past the end of the first SQL statement in zSql. These routines only
  2839. ** compile the first statement in zSql, so *pzTail is left pointing to
  2840. ** what remains uncompiled.
  2841. **
  2842. ** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
  2843. ** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set
  2844. ** to NULL. ^If the input text contains no SQL (if the input is an empty
  2845. ** string or a comment) then *ppStmt is set to NULL.
  2846. ** The calling procedure is responsible for deleting the compiled
  2847. ** SQL statement using [sqlite3_finalize()] after it has finished with it.
  2848. ** ppStmt may not be NULL.
  2849. **
  2850. ** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
  2851. ** otherwise an [error code] is returned.
  2852. **
  2853. ** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are
  2854. ** recommended for all new programs. The two older interfaces are retained
  2855. ** for backwards compatibility, but their use is discouraged.
  2856. ** ^In the "v2" interfaces, the prepared statement
  2857. ** that is returned (the [sqlite3_stmt] object) contains a copy of the
  2858. ** original SQL text. This causes the [sqlite3_step()] interface to
  2859. ** behave differently in three ways:
  2860. **
  2861. ** <ol>
  2862. ** <li>
  2863. ** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
  2864. ** always used to do, [sqlite3_step()] will automatically recompile the SQL
  2865. ** statement and try to run it again.
  2866. ** </li>
  2867. **
  2868. ** <li>
  2869. ** ^When an error occurs, [sqlite3_step()] will return one of the detailed
  2870. ** [error codes] or [extended error codes]. ^The legacy behavior was that
  2871. ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
  2872. ** and the application would have to make a second call to [sqlite3_reset()]
  2873. ** in order to find the underlying cause of the problem. With the "v2" prepare
  2874. ** interfaces, the underlying reason for the error is returned immediately.
  2875. ** </li>
  2876. **
  2877. ** <li>
  2878. ** ^If the specific value bound to [parameter | host parameter] in the
  2879. ** WHERE clause might influence the choice of query plan for a statement,
  2880. ** then the statement will be automatically recompiled, as if there had been
  2881. ** a schema change, on the first [sqlite3_step()] call following any change
  2882. ** to the [sqlite3_bind_text | bindings] of that [parameter].
  2883. ** ^The specific value of WHERE-clause [parameter] might influence the
  2884. ** choice of query plan if the parameter is the left-hand side of a [LIKE]
  2885. ** or [GLOB] operator or if the parameter is compared to an indexed column
  2886. ** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled.
  2887. ** the
  2888. ** </li>
  2889. ** </ol>
  2890. */
  2891. SQLITE_API int sqlite3_prepare(
  2892. sqlite3 *db, /* Database handle */
  2893. const char *zSql, /* SQL statement, UTF-8 encoded */
  2894. int nByte, /* Maximum length of zSql in bytes. */
  2895. sqlite3_stmt **ppStmt, /* OUT: Statement handle */
  2896. const char **pzTail /* OUT: Pointer to unused portion of zSql */
  2897. );
  2898. SQLITE_API int sqlite3_prepare_v2(
  2899. sqlite3 *db, /* Database handle */
  2900. const char *zSql, /* SQL statement, UTF-8 encoded */
  2901. int nByte, /* Maximum length of zSql in bytes. */
  2902. sqlite3_stmt **ppStmt, /* OUT: Statement handle */
  2903. const char **pzTail /* OUT: Pointer to unused portion of zSql */
  2904. );
  2905. SQLITE_API int sqlite3_prepare16(
  2906. sqlite3 *db, /* Database handle */
  2907. const void *zSql, /* SQL statement, UTF-16 encoded */
  2908. int nByte, /* Maximum length of zSql in bytes. */
  2909. sqlite3_stmt **ppStmt, /* OUT: Statement handle */
  2910. const void **pzTail /* OUT: Pointer to unused portion of zSql */
  2911. );
  2912. SQLITE_API int sqlite3_prepare16_v2(
  2913. sqlite3 *db, /* Database handle */
  2914. const void *zSql, /* SQL statement, UTF-16 encoded */
  2915. int nByte, /* Maximum length of zSql in bytes. */
  2916. sqlite3_stmt **ppStmt, /* OUT: Statement handle */
  2917. const void **pzTail /* OUT: Pointer to unused portion of zSql */
  2918. );
  2919. /*
  2920. ** CAPI3REF: Retrieving Statement SQL
  2921. **
  2922. ** ^This interface can be used to retrieve a saved copy of the original
  2923. ** SQL text used to create a [prepared statement] if that statement was
  2924. ** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()].
  2925. */
  2926. SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt);
  2927. /*
  2928. ** CAPI3REF: Determine If An SQL Statement Writes The Database
  2929. **
  2930. ** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
  2931. ** and only if the [prepared statement] X makes no direct changes to
  2932. ** the content of the database file.
  2933. **
  2934. ** Note that [application-defined SQL functions] or
  2935. ** [virtual tables] might change the database indirectly as a side effect.
  2936. ** ^(For example, if an application defines a function "eval()" that
  2937. ** calls [sqlite3_exec()], then the following SQL statement would
  2938. ** change the database file through side-effects:
  2939. **
  2940. ** <blockquote><pre>
  2941. ** SELECT eval('DELETE FROM t1') FROM t2;
  2942. ** </pre></blockquote>
  2943. **
  2944. ** But because the [SELECT] statement does not change the database file
  2945. ** directly, sqlite3_stmt_readonly() would still return true.)^
  2946. **
  2947. ** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
  2948. ** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
  2949. ** since the statements themselves do not actually modify the database but
  2950. ** rather they control the timing of when other statements modify the
  2951. ** database. ^The [ATTACH] and [DETACH] statements also cause
  2952. ** sqlite3_stmt_readonly() to return true since, while those statements
  2953. ** change the configuration of a database connection, they do not make
  2954. ** changes to the content of the database files on disk.
  2955. */
  2956. SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
  2957. /*
  2958. ** CAPI3REF: Determine If A Prepared Statement Has Been Reset
  2959. **
  2960. ** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
  2961. ** [prepared statement] S has been stepped at least once using
  2962. ** [sqlite3_step(S)] but has not run to completion and/or has not
  2963. ** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S)
  2964. ** interface returns false if S is a NULL pointer. If S is not a
  2965. ** NULL pointer and is not a pointer to a valid [prepared statement]
  2966. ** object, then the behavior is undefined and probably undesirable.
  2967. **
  2968. ** This interface can be used in combination [sqlite3_next_stmt()]
  2969. ** to locate all prepared statements associated with a database
  2970. ** connection that are in need of being reset. This can be used,
  2971. ** for example, in diagnostic routines to search for prepared
  2972. ** statements that are holding a transaction open.
  2973. */
  2974. SQLITE_API int sqlite3_stmt_busy(sqlite3_stmt*);
  2975. /*
  2976. ** CAPI3REF: Dynamically Typed Value Object
  2977. ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
  2978. **
  2979. ** SQLite uses the sqlite3_value object to represent all values
  2980. ** that can be stored in a database table. SQLite uses dynamic typing
  2981. ** for the values it stores. ^Values stored in sqlite3_value objects
  2982. ** can be integers, floating point values, strings, BLOBs, or NULL.
  2983. **
  2984. ** An sqlite3_value object may be either "protected" or "unprotected".
  2985. ** Some interfaces require a protected sqlite3_value. Other interfaces
  2986. ** will accept either a protected or an unprotected sqlite3_value.
  2987. ** Every interface that accepts sqlite3_value arguments specifies
  2988. ** whether or not it requires a protected sqlite3_value.
  2989. **
  2990. ** The terms "protected" and "unprotected" refer to whether or not
  2991. ** a mutex is held. An internal mutex is held for a protected
  2992. ** sqlite3_value object but no mutex is held for an unprotected
  2993. ** sqlite3_value object. If SQLite is compiled to be single-threaded
  2994. ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
  2995. ** or if SQLite is run in one of reduced mutex modes
  2996. ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
  2997. ** then there is no distinction between protected and unprotected
  2998. ** sqlite3_value objects and they can be used interchangeably. However,
  2999. ** for maximum code portability it is recommended that applications
  3000. ** still make the distinction between protected and unprotected
  3001. ** sqlite3_value objects even when not strictly required.
  3002. **
  3003. ** ^The sqlite3_value objects that are passed as parameters into the
  3004. ** implementation of [application-defined SQL functions] are protected.
  3005. ** ^The sqlite3_value object returned by
  3006. ** [sqlite3_column_value()] is unprotected.
  3007. ** Unprotected sqlite3_value objects may only be used with
  3008. ** [sqlite3_result_value()] and [sqlite3_bind_value()].
  3009. ** The [sqlite3_value_blob | sqlite3_value_type()] family of
  3010. ** interfaces require protected sqlite3_value objects.
  3011. */
  3012. typedef struct Mem sqlite3_value;
  3013. /*
  3014. ** CAPI3REF: SQL Function Context Object
  3015. **
  3016. ** The context in which an SQL function executes is stored in an
  3017. ** sqlite3_context object. ^A pointer to an sqlite3_context object
  3018. ** is always first parameter to [application-defined SQL functions].
  3019. ** The application-defined SQL function implementation will pass this
  3020. ** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
  3021. ** [sqlite3_aggregate_context()], [sqlite3_user_data()],
  3022. ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
  3023. ** and/or [sqlite3_set_auxdata()].
  3024. */
  3025. typedef struct sqlite3_context sqlite3_context;
  3026. /*
  3027. ** CAPI3REF: Binding Values To Prepared Statements
  3028. ** KEYWORDS: {host parameter} {host parameters} {host parameter name}
  3029. ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
  3030. **
  3031. ** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
  3032. ** literals may be replaced by a [parameter] that matches one of following
  3033. ** templates:
  3034. **
  3035. ** <ul>
  3036. ** <li> ?
  3037. ** <li> ?NNN
  3038. ** <li> :VVV
  3039. ** <li> @VVV
  3040. ** <li> $VVV
  3041. ** </ul>
  3042. **
  3043. ** In the templates above, NNN represents an integer literal,
  3044. ** and VVV represents an alphanumeric identifier.)^ ^The values of these
  3045. ** parameters (also called "host parameter names" or "SQL parameters")
  3046. ** can be set using the sqlite3_bind_*() routines defined here.
  3047. **
  3048. ** ^The first argument to the sqlite3_bind_*() routines is always
  3049. ** a pointer to the [sqlite3_stmt] object returned from
  3050. ** [sqlite3_prepare_v2()] or its variants.
  3051. **
  3052. ** ^The second argument is the index of the SQL parameter to be set.
  3053. ** ^The leftmost SQL parameter has an index of 1. ^When the same named
  3054. ** SQL parameter is used more than once, second and subsequent
  3055. ** occurrences have the same index as the first occurrence.
  3056. ** ^The index for named parameters can be looked up using the
  3057. ** [sqlite3_bind_parameter_index()] API if desired. ^The index
  3058. ** for "?NNN" parameters is the value of NNN.
  3059. ** ^The NNN value must be between 1 and the [sqlite3_limit()]
  3060. ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999).
  3061. **
  3062. ** ^The third argument is the value to bind to the parameter.
  3063. **
  3064. ** ^(In those routines that have a fourth argument, its value is the
  3065. ** number of bytes in the parameter. To be clear: the value is the
  3066. ** number of <u>bytes</u> in the value, not the number of characters.)^
  3067. ** ^If the fourth parameter is negative, the length of the string is
  3068. ** the number of bytes up to the first zero terminator.
  3069. ** If a non-negative fourth parameter is provided to sqlite3_bind_text()
  3070. ** or sqlite3_bind_text16() then that parameter must be the byte offset
  3071. ** where the NUL terminator would occur assuming the string were NUL
  3072. ** terminated. If any NUL characters occur at byte offsets less than
  3073. ** the value of the fourth parameter then the resulting string value will
  3074. ** contain embedded NULs. The result of expressions involving strings
  3075. ** with embedded NULs is undefined.
  3076. **
  3077. ** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and
  3078. ** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or
  3079. ** string after SQLite has finished with it. ^The destructor is called
  3080. ** to dispose of the BLOB or string even if the call to sqlite3_bind_blob(),
  3081. ** sqlite3_bind_text(), or sqlite3_bind_text16() fails.
  3082. ** ^If the fifth argument is
  3083. ** the special value [SQLITE_STATIC], then SQLite assumes that the
  3084. ** information is in static, unmanaged space and does not need to be freed.
  3085. ** ^If the fifth argument has the value [SQLITE_TRANSIENT], then
  3086. ** SQLite makes its own private copy of the data immediately, before
  3087. ** the sqlite3_bind_*() routine returns.
  3088. **
  3089. ** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
  3090. ** is filled with zeroes. ^A zeroblob uses a fixed amount of memory
  3091. ** (just an integer to hold its size) while it is being processed.
  3092. ** Zeroblobs are intended to serve as placeholders for BLOBs whose
  3093. ** content is later written using
  3094. ** [sqlite3_blob_open | incremental BLOB I/O] routines.
  3095. ** ^A negative value for the zeroblob results in a zero-length BLOB.
  3096. **
  3097. ** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
  3098. ** for the [prepared statement] or with a prepared statement for which
  3099. ** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
  3100. ** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_()
  3101. ** routine is passed a [prepared statement] that has been finalized, the
  3102. ** result is undefined and probably harmful.
  3103. **
  3104. ** ^Bindings are not cleared by the [sqlite3_reset()] routine.
  3105. ** ^Unbound parameters are interpreted as NULL.
  3106. **
  3107. ** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
  3108. ** [error code] if anything goes wrong.
  3109. ** ^[SQLITE_RANGE] is returned if the parameter
  3110. ** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails.
  3111. **
  3112. ** See also: [sqlite3_bind_parameter_count()],
  3113. ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
  3114. */
  3115. SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
  3116. SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double);
  3117. SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int);
  3118. SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
  3119. SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int);
  3120. SQLITE_API int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*));
  3121. SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
  3122. SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
  3123. SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
  3124. /*
  3125. ** CAPI3REF: Number Of SQL Parameters
  3126. **
  3127. ** ^This routine can be used to find the number of [SQL parameters]
  3128. ** in a [prepared statement]. SQL parameters are tokens of the
  3129. ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
  3130. ** placeholders for values that are [sqlite3_bind_blob | bound]
  3131. ** to the parameters at a later time.
  3132. **
  3133. ** ^(This routine actually returns the index of the largest (rightmost)
  3134. ** parameter. For all forms except ?NNN, this will correspond to the
  3135. ** number of unique parameters. If parameters of the ?NNN form are used,
  3136. ** there may be gaps in the list.)^
  3137. **
  3138. ** See also: [sqlite3_bind_blob|sqlite3_bind()],
  3139. ** [sqlite3_bind_parameter_name()], and
  3140. ** [sqlite3_bind_parameter_index()].
  3141. */
  3142. SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*);
  3143. /*
  3144. ** CAPI3REF: Name Of A Host Parameter
  3145. **
  3146. ** ^The sqlite3_bind_parameter_name(P,N) interface returns
  3147. ** the name of the N-th [SQL parameter] in the [prepared statement] P.
  3148. ** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
  3149. ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
  3150. ** respectively.
  3151. ** In other words, the initial ":" or "$" or "@" or "?"
  3152. ** is included as part of the name.)^
  3153. ** ^Parameters of the form "?" without a following integer have no name
  3154. ** and are referred to as "nameless" or "anonymous parameters".
  3155. **
  3156. ** ^The first host parameter has an index of 1, not 0.
  3157. **
  3158. ** ^If the value N is out of range or if the N-th parameter is
  3159. ** nameless, then NULL is returned. ^The returned string is
  3160. ** always in UTF-8 encoding even if the named parameter was
  3161. ** originally specified as UTF-16 in [sqlite3_prepare16()] or
  3162. ** [sqlite3_prepare16_v2()].
  3163. **
  3164. ** See also: [sqlite3_bind_blob|sqlite3_bind()],
  3165. ** [sqlite3_bind_parameter_count()], and
  3166. ** [sqlite3_bind_parameter_index()].
  3167. */
  3168. SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
  3169. /*
  3170. ** CAPI3REF: Index Of A Parameter With A Given Name
  3171. **
  3172. ** ^Return the index of an SQL parameter given its name. ^The
  3173. ** index value returned is suitable for use as the second
  3174. ** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero
  3175. ** is returned if no matching parameter is found. ^The parameter
  3176. ** name must be given in UTF-8 even if the original statement
  3177. ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()].
  3178. **
  3179. ** See also: [sqlite3_bind_blob|sqlite3_bind()],
  3180. ** [sqlite3_bind_parameter_count()], and
  3181. ** [sqlite3_bind_parameter_index()].
  3182. */
  3183. SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
  3184. /*
  3185. ** CAPI3REF: Reset All Bindings On A Prepared Statement
  3186. **
  3187. ** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
  3188. ** the [sqlite3_bind_blob | bindings] on a [prepared statement].
  3189. ** ^Use this routine to reset all host parameters to NULL.
  3190. */
  3191. SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*);
  3192. /*
  3193. ** CAPI3REF: Number Of Columns In A Result Set
  3194. **
  3195. ** ^Return the number of columns in the result set returned by the
  3196. ** [prepared statement]. ^This routine returns 0 if pStmt is an SQL
  3197. ** statement that does not return data (for example an [UPDATE]).
  3198. **
  3199. ** See also: [sqlite3_data_count()]
  3200. */
  3201. SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt);
  3202. /*
  3203. ** CAPI3REF: Column Names In A Result Set
  3204. **
  3205. ** ^These routines return the name assigned to a particular column
  3206. ** in the result set of a [SELECT] statement. ^The sqlite3_column_name()
  3207. ** interface returns a pointer to a zero-terminated UTF-8 string
  3208. ** and sqlite3_column_name16() returns a pointer to a zero-terminated
  3209. ** UTF-16 string. ^The first parameter is the [prepared statement]
  3210. ** that implements the [SELECT] statement. ^The second parameter is the
  3211. ** column number. ^The leftmost column is number 0.
  3212. **
  3213. ** ^The returned string pointer is valid until either the [prepared statement]
  3214. ** is destroyed by [sqlite3_finalize()] or until the statement is automatically
  3215. ** reprepared by the first call to [sqlite3_step()] for a particular run
  3216. ** or until the next call to
  3217. ** sqlite3_column_name() or sqlite3_column_name16() on the same column.
  3218. **
  3219. ** ^If sqlite3_malloc() fails during the processing of either routine
  3220. ** (for example during a conversion from UTF-8 to UTF-16) then a
  3221. ** NULL pointer is returned.
  3222. **
  3223. ** ^The name of a result column is the value of the "AS" clause for
  3224. ** that column, if there is an AS clause. If there is no AS clause
  3225. ** then the name of the column is unspecified and may change from
  3226. ** one release of SQLite to the next.
  3227. */
  3228. SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N);
  3229. SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N);
  3230. /*
  3231. ** CAPI3REF: Source Of Data In A Query Result
  3232. **
  3233. ** ^These routines provide a means to determine the database, table, and
  3234. ** table column that is the origin of a particular result column in
  3235. ** [SELECT] statement.
  3236. ** ^The name of the database or table or column can be returned as
  3237. ** either a UTF-8 or UTF-16 string. ^The _database_ routines return
  3238. ** the database name, the _table_ routines return the table name, and
  3239. ** the origin_ routines return the column name.
  3240. ** ^The returned string is valid until the [prepared statement] is destroyed
  3241. ** using [sqlite3_finalize()] or until the statement is automatically
  3242. ** reprepared by the first call to [sqlite3_step()] for a particular run
  3243. ** or until the same information is requested
  3244. ** again in a different encoding.
  3245. **
  3246. ** ^The names returned are the original un-aliased names of the
  3247. ** database, table, and column.
  3248. **
  3249. ** ^The first argument to these interfaces is a [prepared statement].
  3250. ** ^These functions return information about the Nth result column returned by
  3251. ** the statement, where N is the second function argument.
  3252. ** ^The left-most column is column 0 for these routines.
  3253. **
  3254. ** ^If the Nth column returned by the statement is an expression or
  3255. ** subquery and is not a column value, then all of these functions return
  3256. ** NULL. ^These routine might also return NULL if a memory allocation error
  3257. ** occurs. ^Otherwise, they return the name of the attached database, table,
  3258. ** or column that query result column was extracted from.
  3259. **
  3260. ** ^As with all other SQLite APIs, those whose names end with "16" return
  3261. ** UTF-16 encoded strings and the other functions return UTF-8.
  3262. **
  3263. ** ^These APIs are only available if the library was compiled with the
  3264. ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
  3265. **
  3266. ** If two or more threads call one or more of these routines against the same
  3267. ** prepared statement and column at the same time then the results are
  3268. ** undefined.
  3269. **
  3270. ** If two or more threads call one or more
  3271. ** [sqlite3_column_database_name | column metadata interfaces]
  3272. ** for the same [prepared statement] and result column
  3273. ** at the same time then the results are undefined.
  3274. */
  3275. SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int);
  3276. SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
  3277. SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int);
  3278. SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
  3279. SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
  3280. SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
  3281. /*
  3282. ** CAPI3REF: Declared Datatype Of A Query Result
  3283. **
  3284. ** ^(The first parameter is a [prepared statement].
  3285. ** If this statement is a [SELECT] statement and the Nth column of the
  3286. ** returned result set of that [SELECT] is a table column (not an
  3287. ** expression or subquery) then the declared type of the table
  3288. ** column is returned.)^ ^If the Nth column of the result set is an
  3289. ** expression or subquery, then a NULL pointer is returned.
  3290. ** ^The returned string is always UTF-8 encoded.
  3291. **
  3292. ** ^(For example, given the database schema:
  3293. **
  3294. ** CREATE TABLE t1(c1 VARIANT);
  3295. **
  3296. ** and the following statement to be compiled:
  3297. **
  3298. ** SELECT c1 + 1, c1 FROM t1;
  3299. **
  3300. ** this routine would return the string "VARIANT" for the second result
  3301. ** column (i==1), and a NULL pointer for the first result column (i==0).)^
  3302. **
  3303. ** ^SQLite uses dynamic run-time typing. ^So just because a column
  3304. ** is declared to contain a particular type does not mean that the
  3305. ** data stored in that column is of the declared type. SQLite is
  3306. ** strongly typed, but the typing is dynamic not static. ^Type
  3307. ** is associated with individual values, not with the containers
  3308. ** used to hold those values.
  3309. */
  3310. SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int);
  3311. SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
  3312. /*
  3313. ** CAPI3REF: Evaluate An SQL Statement
  3314. **
  3315. ** After a [prepared statement] has been prepared using either
  3316. ** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy
  3317. ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
  3318. ** must be called one or more times to evaluate the statement.
  3319. **
  3320. ** The details of the behavior of the sqlite3_step() interface depend
  3321. ** on whether the statement was prepared using the newer "v2" interface
  3322. ** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy
  3323. ** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the
  3324. ** new "v2" interface is recommended for new applications but the legacy
  3325. ** interface will continue to be supported.
  3326. **
  3327. ** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
  3328. ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
  3329. ** ^With the "v2" interface, any of the other [result codes] or
  3330. ** [extended result codes] might be returned as well.
  3331. **
  3332. ** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
  3333. ** database locks it needs to do its job. ^If the statement is a [COMMIT]
  3334. ** or occurs outside of an explicit transaction, then you can retry the
  3335. ** statement. If the statement is not a [COMMIT] and occurs within an
  3336. ** explicit transaction then you should rollback the transaction before
  3337. ** continuing.
  3338. **
  3339. ** ^[SQLITE_DONE] means that the statement has finished executing
  3340. ** successfully. sqlite3_step() should not be called again on this virtual
  3341. ** machine without first calling [sqlite3_reset()] to reset the virtual
  3342. ** machine back to its initial state.
  3343. **
  3344. ** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
  3345. ** is returned each time a new row of data is ready for processing by the
  3346. ** caller. The values may be accessed using the [column access functions].
  3347. ** sqlite3_step() is called again to retrieve the next row of data.
  3348. **
  3349. ** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
  3350. ** violation) has occurred. sqlite3_step() should not be called again on
  3351. ** the VM. More information may be found by calling [sqlite3_errmsg()].
  3352. ** ^With the legacy interface, a more specific error code (for example,
  3353. ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
  3354. ** can be obtained by calling [sqlite3_reset()] on the
  3355. ** [prepared statement]. ^In the "v2" interface,
  3356. ** the more specific error code is returned directly by sqlite3_step().
  3357. **
  3358. ** [SQLITE_MISUSE] means that the this routine was called inappropriately.
  3359. ** Perhaps it was called on a [prepared statement] that has
  3360. ** already been [sqlite3_finalize | finalized] or on one that had
  3361. ** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could
  3362. ** be the case that the same database connection is being used by two or
  3363. ** more threads at the same moment in time.
  3364. **
  3365. ** For all versions of SQLite up to and including 3.6.23.1, a call to
  3366. ** [sqlite3_reset()] was required after sqlite3_step() returned anything
  3367. ** other than [SQLITE_ROW] before any subsequent invocation of
  3368. ** sqlite3_step(). Failure to reset the prepared statement using
  3369. ** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
  3370. ** sqlite3_step(). But after version 3.6.23.1, sqlite3_step() began
  3371. ** calling [sqlite3_reset()] automatically in this circumstance rather
  3372. ** than returning [SQLITE_MISUSE]. This is not considered a compatibility
  3373. ** break because any application that ever receives an SQLITE_MISUSE error
  3374. ** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option
  3375. ** can be used to restore the legacy behavior.
  3376. **
  3377. ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
  3378. ** API always returns a generic error code, [SQLITE_ERROR], following any
  3379. ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call
  3380. ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
  3381. ** specific [error codes] that better describes the error.
  3382. ** We admit that this is a goofy design. The problem has been fixed
  3383. ** with the "v2" interface. If you prepare all of your SQL statements
  3384. ** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead
  3385. ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
  3386. ** then the more specific [error codes] are returned directly
  3387. ** by sqlite3_step(). The use of the "v2" interface is recommended.
  3388. */
  3389. SQLITE_API int sqlite3_step(sqlite3_stmt*);
  3390. /*
  3391. ** CAPI3REF: Number of columns in a result set
  3392. **
  3393. ** ^The sqlite3_data_count(P) interface returns the number of columns in the
  3394. ** current row of the result set of [prepared statement] P.
  3395. ** ^If prepared statement P does not have results ready to return
  3396. ** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of
  3397. ** interfaces) then sqlite3_data_count(P) returns 0.
  3398. ** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
  3399. ** ^The sqlite3_data_count(P) routine returns 0 if the previous call to
  3400. ** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P)
  3401. ** will return non-zero if previous call to [sqlite3_step](P) returned
  3402. ** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum]
  3403. ** where it always returns zero since each step of that multi-step
  3404. ** pragma returns 0 columns of data.
  3405. **
  3406. ** See also: [sqlite3_column_count()]
  3407. */
  3408. SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
  3409. /*
  3410. ** CAPI3REF: Fundamental Datatypes
  3411. ** KEYWORDS: SQLITE_TEXT
  3412. **
  3413. ** ^(Every value in SQLite has one of five fundamental datatypes:
  3414. **
  3415. ** <ul>
  3416. ** <li> 64-bit signed integer
  3417. ** <li> 64-bit IEEE floating point number
  3418. ** <li> string
  3419. ** <li> BLOB
  3420. ** <li> NULL
  3421. ** </ul>)^
  3422. **
  3423. ** These constants are codes for each of those types.
  3424. **
  3425. ** Note that the SQLITE_TEXT constant was also used in SQLite version 2
  3426. ** for a completely different meaning. Software that links against both
  3427. ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
  3428. ** SQLITE_TEXT.
  3429. */
  3430. #define SQLITE_INTEGER 1
  3431. #define SQLITE_FLOAT 2
  3432. #define SQLITE_BLOB 4
  3433. #define SQLITE_NULL 5
  3434. #ifdef SQLITE_TEXT
  3435. # undef SQLITE_TEXT
  3436. #else
  3437. # define SQLITE_TEXT 3
  3438. #endif
  3439. #define SQLITE3_TEXT 3
  3440. /*
  3441. ** CAPI3REF: Result Values From A Query
  3442. ** KEYWORDS: {column access functions}
  3443. **
  3444. ** These routines form the "result set" interface.
  3445. **
  3446. ** ^These routines return information about a single column of the current
  3447. ** result row of a query. ^In every case the first argument is a pointer
  3448. ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
  3449. ** that was returned from [sqlite3_prepare_v2()] or one of its variants)
  3450. ** and the second argument is the index of the column for which information
  3451. ** should be returned. ^The leftmost column of the result set has the index 0.
  3452. ** ^The number of columns in the result can be determined using
  3453. ** [sqlite3_column_count()].
  3454. **
  3455. ** If the SQL statement does not currently point to a valid row, or if the
  3456. ** column index is out of range, the result is undefined.
  3457. ** These routines may only be called when the most recent call to
  3458. ** [sqlite3_step()] has returned [SQLITE_ROW] and neither
  3459. ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
  3460. ** If any of these routines are called after [sqlite3_reset()] or
  3461. ** [sqlite3_finalize()] or after [sqlite3_step()] has returned
  3462. ** something other than [SQLITE_ROW], the results are undefined.
  3463. ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
  3464. ** are called from a different thread while any of these routines
  3465. ** are pending, then the results are undefined.
  3466. **
  3467. ** ^The sqlite3_column_type() routine returns the
  3468. ** [SQLITE_INTEGER | datatype code] for the initial data type
  3469. ** of the result column. ^The returned value is one of [SQLITE_INTEGER],
  3470. ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value
  3471. ** returned by sqlite3_column_type() is only meaningful if no type
  3472. ** conversions have occurred as described below. After a type conversion,
  3473. ** the value returned by sqlite3_column_type() is undefined. Future
  3474. ** versions of SQLite may change the behavior of sqlite3_column_type()
  3475. ** following a type conversion.
  3476. **
  3477. ** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
  3478. ** routine returns the number of bytes in that BLOB or string.
  3479. ** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
  3480. ** the string to UTF-8 and then returns the number of bytes.
  3481. ** ^If the result is a numeric value then sqlite3_column_bytes() uses
  3482. ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
  3483. ** the number of bytes in that string.
  3484. ** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
  3485. **
  3486. ** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
  3487. ** routine returns the number of bytes in that BLOB or string.
  3488. ** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
  3489. ** the string to UTF-16 and then returns the number of bytes.
  3490. ** ^If the result is a numeric value then sqlite3_column_bytes16() uses
  3491. ** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
  3492. ** the number of bytes in that string.
  3493. ** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
  3494. **
  3495. ** ^The values returned by [sqlite3_column_bytes()] and
  3496. ** [sqlite3_column_bytes16()] do not include the zero terminators at the end
  3497. ** of the string. ^For clarity: the values returned by
  3498. ** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
  3499. ** bytes in the string, not the number of characters.
  3500. **
  3501. ** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
  3502. ** even empty strings, are always zero-terminated. ^The return
  3503. ** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
  3504. **
  3505. ** ^The object returned by [sqlite3_column_value()] is an
  3506. ** [unprotected sqlite3_value] object. An unprotected sqlite3_value object
  3507. ** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()].
  3508. ** If the [unprotected sqlite3_value] object returned by
  3509. ** [sqlite3_column_value()] is used in any other way, including calls
  3510. ** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
  3511. ** or [sqlite3_value_bytes()], then the behavior is undefined.
  3512. **
  3513. ** These routines attempt to convert the value where appropriate. ^For
  3514. ** example, if the internal representation is FLOAT and a text result
  3515. ** is requested, [sqlite3_snprintf()] is used internally to perform the
  3516. ** conversion automatically. ^(The following table details the conversions
  3517. ** that are applied:
  3518. **
  3519. ** <blockquote>
  3520. ** <table border="1">
  3521. ** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion
  3522. **
  3523. ** <tr><td> NULL <td> INTEGER <td> Result is 0
  3524. ** <tr><td> NULL <td> FLOAT <td> Result is 0.0
  3525. ** <tr><td> NULL <td> TEXT <td> Result is NULL pointer
  3526. ** <tr><td> NULL <td> BLOB <td> Result is NULL pointer
  3527. ** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float
  3528. ** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer
  3529. ** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT
  3530. ** <tr><td> FLOAT <td> INTEGER <td> Convert from float to integer
  3531. ** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float
  3532. ** <tr><td> FLOAT <td> BLOB <td> Same as FLOAT->TEXT
  3533. ** <tr><td> TEXT <td> INTEGER <td> Use atoi()
  3534. ** <tr><td> TEXT <td> FLOAT <td> Use atof()
  3535. ** <tr><td> TEXT <td> BLOB <td> No change
  3536. ** <tr><td> BLOB <td> INTEGER <td> Convert to TEXT then use atoi()
  3537. ** <tr><td> BLOB <td> FLOAT <td> Convert to TEXT then use atof()
  3538. ** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed
  3539. ** </table>
  3540. ** </blockquote>)^
  3541. **
  3542. ** The table above makes reference to standard C library functions atoi()
  3543. ** and atof(). SQLite does not really use these functions. It has its
  3544. ** own equivalent internal routines. The atoi() and atof() names are
  3545. ** used in the table for brevity and because they are familiar to most
  3546. ** C programmers.
  3547. **
  3548. ** Note that when type conversions occur, pointers returned by prior
  3549. ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
  3550. ** sqlite3_column_text16() may be invalidated.
  3551. ** Type conversions and pointer invalidations might occur
  3552. ** in the following cases:
  3553. **
  3554. ** <ul>
  3555. ** <li> The initial content is a BLOB and sqlite3_column_text() or
  3556. ** sqlite3_column_text16() is called. A zero-terminator might
  3557. ** need to be added to the string.</li>
  3558. ** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
  3559. ** sqlite3_column_text16() is called. The content must be converted
  3560. ** to UTF-16.</li>
  3561. ** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
  3562. ** sqlite3_column_text() is called. The content must be converted
  3563. ** to UTF-8.</li>
  3564. ** </ul>
  3565. **
  3566. ** ^Conversions between UTF-16be and UTF-16le are always done in place and do
  3567. ** not invalidate a prior pointer, though of course the content of the buffer
  3568. ** that the prior pointer references will have been modified. Other kinds
  3569. ** of conversion are done in place when it is possible, but sometimes they
  3570. ** are not possible and in those cases prior pointers are invalidated.
  3571. **
  3572. ** The safest and easiest to remember policy is to invoke these routines
  3573. ** in one of the following ways:
  3574. **
  3575. ** <ul>
  3576. ** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
  3577. ** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
  3578. ** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
  3579. ** </ul>
  3580. **
  3581. ** In other words, you should call sqlite3_column_text(),
  3582. ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
  3583. ** into the desired format, then invoke sqlite3_column_bytes() or
  3584. ** sqlite3_column_bytes16() to find the size of the result. Do not mix calls
  3585. ** to sqlite3_column_text() or sqlite3_column_blob() with calls to
  3586. ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
  3587. ** with calls to sqlite3_column_bytes().
  3588. **
  3589. ** ^The pointers returned are valid until a type conversion occurs as
  3590. ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
  3591. ** [sqlite3_finalize()] is called. ^The memory space used to hold strings
  3592. ** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned
  3593. ** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
  3594. ** [sqlite3_free()].
  3595. **
  3596. ** ^(If a memory allocation error occurs during the evaluation of any
  3597. ** of these routines, a default value is returned. The default value
  3598. ** is either the integer 0, the floating point number 0.0, or a NULL
  3599. ** pointer. Subsequent calls to [sqlite3_errcode()] will return
  3600. ** [SQLITE_NOMEM].)^
  3601. */
  3602. SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
  3603. SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
  3604. SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
  3605. SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol);
  3606. SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol);
  3607. SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
  3608. SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
  3609. SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
  3610. SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol);
  3611. SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
  3612. /*
  3613. ** CAPI3REF: Destroy A Prepared Statement Object
  3614. **
  3615. ** ^The sqlite3_finalize() function is called to delete a [prepared statement].
  3616. ** ^If the most recent evaluation of the statement encountered no errors
  3617. ** or if the statement is never been evaluated, then sqlite3_finalize() returns
  3618. ** SQLITE_OK. ^If the most recent evaluation of statement S failed, then
  3619. ** sqlite3_finalize(S) returns the appropriate [error code] or
  3620. ** [extended error code].
  3621. **
  3622. ** ^The sqlite3_finalize(S) routine can be called at any point during
  3623. ** the life cycle of [prepared statement] S:
  3624. ** before statement S is ever evaluated, after
  3625. ** one or more calls to [sqlite3_reset()], or after any call
  3626. ** to [sqlite3_step()] regardless of whether or not the statement has
  3627. ** completed execution.
  3628. **
  3629. ** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
  3630. **
  3631. ** The application must finalize every [prepared statement] in order to avoid
  3632. ** resource leaks. It is a grievous error for the application to try to use
  3633. ** a prepared statement after it has been finalized. Any use of a prepared
  3634. ** statement after it has been finalized can result in undefined and
  3635. ** undesirable behavior such as segfaults and heap corruption.
  3636. */
  3637. SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt);
  3638. /*
  3639. ** CAPI3REF: Reset A Prepared Statement Object
  3640. **
  3641. ** The sqlite3_reset() function is called to reset a [prepared statement]
  3642. ** object back to its initial state, ready to be re-executed.
  3643. ** ^Any SQL statement variables that had values bound to them using
  3644. ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
  3645. ** Use [sqlite3_clear_bindings()] to reset the bindings.
  3646. **
  3647. ** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
  3648. ** back to the beginning of its program.
  3649. **
  3650. ** ^If the most recent call to [sqlite3_step(S)] for the
  3651. ** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
  3652. ** or if [sqlite3_step(S)] has never before been called on S,
  3653. ** then [sqlite3_reset(S)] returns [SQLITE_OK].
  3654. **
  3655. ** ^If the most recent call to [sqlite3_step(S)] for the
  3656. ** [prepared statement] S indicated an error, then
  3657. ** [sqlite3_reset(S)] returns an appropriate [error code].
  3658. **
  3659. ** ^The [sqlite3_reset(S)] interface does not change the values
  3660. ** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
  3661. */
  3662. SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt);
  3663. /*
  3664. ** CAPI3REF: Create Or Redefine SQL Functions
  3665. ** KEYWORDS: {function creation routines}
  3666. ** KEYWORDS: {application-defined SQL function}
  3667. ** KEYWORDS: {application-defined SQL functions}
  3668. **
  3669. ** ^These functions (collectively known as "function creation routines")
  3670. ** are used to add SQL functions or aggregates or to redefine the behavior
  3671. ** of existing SQL functions or aggregates. The only differences between
  3672. ** these routines are the text encoding expected for
  3673. ** the second parameter (the name of the function being created)
  3674. ** and the presence or absence of a destructor callback for
  3675. ** the application data pointer.
  3676. **
  3677. ** ^The first parameter is the [database connection] to which the SQL
  3678. ** function is to be added. ^If an application uses more than one database
  3679. ** connection then application-defined SQL functions must be added
  3680. ** to each database connection separately.
  3681. **
  3682. ** ^The second parameter is the name of the SQL function to be created or
  3683. ** redefined. ^The length of the name is limited to 255 bytes in a UTF-8
  3684. ** representation, exclusive of the zero-terminator. ^Note that the name
  3685. ** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
  3686. ** ^Any attempt to create a function with a longer name
  3687. ** will result in [SQLITE_MISUSE] being returned.
  3688. **
  3689. ** ^The third parameter (nArg)
  3690. ** is the number of arguments that the SQL function or
  3691. ** aggregate takes. ^If this parameter is -1, then the SQL function or
  3692. ** aggregate may take any number of arguments between 0 and the limit
  3693. ** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third
  3694. ** parameter is less than -1 or greater than 127 then the behavior is
  3695. ** undefined.
  3696. **
  3697. ** ^The fourth parameter, eTextRep, specifies what
  3698. ** [SQLITE_UTF8 | text encoding] this SQL function prefers for
  3699. ** its parameters. Every SQL function implementation must be able to work
  3700. ** with UTF-8, UTF-16le, or UTF-16be. But some implementations may be
  3701. ** more efficient with one encoding than another. ^An application may
  3702. ** invoke sqlite3_create_function() or sqlite3_create_function16() multiple
  3703. ** times with the same function but with different values of eTextRep.
  3704. ** ^When multiple implementations of the same function are available, SQLite
  3705. ** will pick the one that involves the least amount of data conversion.
  3706. ** If there is only a single implementation which does not care what text
  3707. ** encoding is used, then the fourth argument should be [SQLITE_ANY].
  3708. **
  3709. ** ^(The fifth parameter is an arbitrary pointer. The implementation of the
  3710. ** function can gain access to this pointer using [sqlite3_user_data()].)^
  3711. **
  3712. ** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are
  3713. ** pointers to C-language functions that implement the SQL function or
  3714. ** aggregate. ^A scalar SQL function requires an implementation of the xFunc
  3715. ** callback only; NULL pointers must be passed as the xStep and xFinal
  3716. ** parameters. ^An aggregate SQL function requires an implementation of xStep
  3717. ** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
  3718. ** SQL function or aggregate, pass NULL pointers for all three function
  3719. ** callbacks.
  3720. **
  3721. ** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL,
  3722. ** then it is destructor for the application data pointer.
  3723. ** The destructor is invoked when the function is deleted, either by being
  3724. ** overloaded or when the database connection closes.)^
  3725. ** ^The destructor is also invoked if the call to
  3726. ** sqlite3_create_function_v2() fails.
  3727. ** ^When the destructor callback of the tenth parameter is invoked, it
  3728. ** is passed a single argument which is a copy of the application data
  3729. ** pointer which was the fifth parameter to sqlite3_create_function_v2().
  3730. **
  3731. ** ^It is permitted to register multiple implementations of the same
  3732. ** functions with the same name but with either differing numbers of
  3733. ** arguments or differing preferred text encodings. ^SQLite will use
  3734. ** the implementation that most closely matches the way in which the
  3735. ** SQL function is used. ^A function implementation with a non-negative
  3736. ** nArg parameter is a better match than a function implementation with
  3737. ** a negative nArg. ^A function where the preferred text encoding
  3738. ** matches the database encoding is a better
  3739. ** match than a function where the encoding is different.
  3740. ** ^A function where the encoding difference is between UTF16le and UTF16be
  3741. ** is a closer match than a function where the encoding difference is
  3742. ** between UTF8 and UTF16.
  3743. **
  3744. ** ^Built-in functions may be overloaded by new application-defined functions.
  3745. **
  3746. ** ^An application-defined function is permitted to call other
  3747. ** SQLite interfaces. However, such calls must not
  3748. ** close the database connection nor finalize or reset the prepared
  3749. ** statement in which the function is running.
  3750. */
  3751. SQLITE_API int sqlite3_create_function(
  3752. sqlite3 *db,
  3753. const char *zFunctionName,
  3754. int nArg,
  3755. int eTextRep,
  3756. void *pApp,
  3757. void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
  3758. void (*xStep)(sqlite3_context*,int,sqlite3_value**),
  3759. void (*xFinal)(sqlite3_context*)
  3760. );
  3761. SQLITE_API int sqlite3_create_function16(
  3762. sqlite3 *db,
  3763. const void *zFunctionName,
  3764. int nArg,
  3765. int eTextRep,
  3766. void *pApp,
  3767. void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
  3768. void (*xStep)(sqlite3_context*,int,sqlite3_value**),
  3769. void (*xFinal)(sqlite3_context*)
  3770. );
  3771. SQLITE_API int sqlite3_create_function_v2(
  3772. sqlite3 *db,
  3773. const char *zFunctionName,
  3774. int nArg,
  3775. int eTextRep,
  3776. void *pApp,
  3777. void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
  3778. void (*xStep)(sqlite3_context*,int,sqlite3_value**),
  3779. void (*xFinal)(sqlite3_context*),
  3780. void(*xDestroy)(void*)
  3781. );
  3782. /*
  3783. ** CAPI3REF: Text Encodings
  3784. **
  3785. ** These constant define integer codes that represent the various
  3786. ** text encodings supported by SQLite.
  3787. */
  3788. #define SQLITE_UTF8 1
  3789. #define SQLITE_UTF16LE 2
  3790. #define SQLITE_UTF16BE 3
  3791. #define SQLITE_UTF16 4 /* Use native byte order */
  3792. #define SQLITE_ANY 5 /* sqlite3_create_function only */
  3793. #define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */
  3794. /*
  3795. ** CAPI3REF: Deprecated Functions
  3796. ** DEPRECATED
  3797. **
  3798. ** These functions are [deprecated]. In order to maintain
  3799. ** backwards compatibility with older code, these functions continue
  3800. ** to be supported. However, new applications should avoid
  3801. ** the use of these functions. To help encourage people to avoid
  3802. ** using these functions, we are not going to tell you what they do.
  3803. */
  3804. #ifndef SQLITE_OMIT_DEPRECATED
  3805. SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
  3806. SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
  3807. SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
  3808. SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void);
  3809. SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
  3810. SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64);
  3811. #endif
  3812. /*
  3813. ** CAPI3REF: Obtaining SQL Function Parameter Values
  3814. **
  3815. ** The C-language implementation of SQL functions and aggregates uses
  3816. ** this set of interface routines to access the parameter values on
  3817. ** the function or aggregate.
  3818. **
  3819. ** The xFunc (for scalar functions) or xStep (for aggregates) parameters
  3820. ** to [sqlite3_create_function()] and [sqlite3_create_function16()]
  3821. ** define callbacks that implement the SQL functions and aggregates.
  3822. ** The 3rd parameter to these callbacks is an array of pointers to
  3823. ** [protected sqlite3_value] objects. There is one [sqlite3_value] object for
  3824. ** each parameter to the SQL function. These routines are used to
  3825. ** extract values from the [sqlite3_value] objects.
  3826. **
  3827. ** These routines work only with [protected sqlite3_value] objects.
  3828. ** Any attempt to use these routines on an [unprotected sqlite3_value]
  3829. ** object results in undefined behavior.
  3830. **
  3831. ** ^These routines work just like the corresponding [column access functions]
  3832. ** except that these routines take a single [protected sqlite3_value] object
  3833. ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
  3834. **
  3835. ** ^The sqlite3_value_text16() interface extracts a UTF-16 string
  3836. ** in the native byte-order of the host machine. ^The
  3837. ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
  3838. ** extract UTF-16 strings as big-endian and little-endian respectively.
  3839. **
  3840. ** ^(The sqlite3_value_numeric_type() interface attempts to apply
  3841. ** numeric affinity to the value. This means that an attempt is
  3842. ** made to convert the value to an integer or floating point. If
  3843. ** such a conversion is possible without loss of information (in other
  3844. ** words, if the value is a string that looks like a number)
  3845. ** then the conversion is performed. Otherwise no conversion occurs.
  3846. ** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
  3847. **
  3848. ** Please pay particular attention to the fact that the pointer returned
  3849. ** from [sqlite3_value_blob()], [sqlite3_value_text()], or
  3850. ** [sqlite3_value_text16()] can be invalidated by a subsequent call to
  3851. ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
  3852. ** or [sqlite3_value_text16()].
  3853. **
  3854. ** These routines must be called from the same thread as
  3855. ** the SQL function that supplied the [sqlite3_value*] parameters.
  3856. */
  3857. SQLITE_API const void *sqlite3_value_blob(sqlite3_value*);
  3858. SQLITE_API int sqlite3_value_bytes(sqlite3_value*);
  3859. SQLITE_API int sqlite3_value_bytes16(sqlite3_value*);
  3860. SQLITE_API double sqlite3_value_double(sqlite3_value*);
  3861. SQLITE_API int sqlite3_value_int(sqlite3_value*);
  3862. SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
  3863. SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*);
  3864. SQLITE_API const void *sqlite3_value_text16(sqlite3_value*);
  3865. SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*);
  3866. SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*);
  3867. SQLITE_API int sqlite3_value_type(sqlite3_value*);
  3868. SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*);
  3869. /*
  3870. ** CAPI3REF: Obtain Aggregate Function Context
  3871. **
  3872. ** Implementations of aggregate SQL functions use this
  3873. ** routine to allocate memory for storing their state.
  3874. **
  3875. ** ^The first time the sqlite3_aggregate_context(C,N) routine is called
  3876. ** for a particular aggregate function, SQLite
  3877. ** allocates N of memory, zeroes out that memory, and returns a pointer
  3878. ** to the new memory. ^On second and subsequent calls to
  3879. ** sqlite3_aggregate_context() for the same aggregate function instance,
  3880. ** the same buffer is returned. Sqlite3_aggregate_context() is normally
  3881. ** called once for each invocation of the xStep callback and then one
  3882. ** last time when the xFinal callback is invoked. ^(When no rows match
  3883. ** an aggregate query, the xStep() callback of the aggregate function
  3884. ** implementation is never called and xFinal() is called exactly once.
  3885. ** In those cases, sqlite3_aggregate_context() might be called for the
  3886. ** first time from within xFinal().)^
  3887. **
  3888. ** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer if N is
  3889. ** less than or equal to zero or if a memory allocate error occurs.
  3890. **
  3891. ** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
  3892. ** determined by the N parameter on first successful call. Changing the
  3893. ** value of N in subsequent call to sqlite3_aggregate_context() within
  3894. ** the same aggregate function instance will not resize the memory
  3895. ** allocation.)^
  3896. **
  3897. ** ^SQLite automatically frees the memory allocated by
  3898. ** sqlite3_aggregate_context() when the aggregate query concludes.
  3899. **
  3900. ** The first parameter must be a copy of the
  3901. ** [sqlite3_context | SQL function context] that is the first parameter
  3902. ** to the xStep or xFinal callback routine that implements the aggregate
  3903. ** function.
  3904. **
  3905. ** This routine must be called from the same thread in which
  3906. ** the aggregate SQL function is running.
  3907. */
  3908. SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
  3909. /*
  3910. ** CAPI3REF: User Data For Functions
  3911. **
  3912. ** ^The sqlite3_user_data() interface returns a copy of
  3913. ** the pointer that was the pUserData parameter (the 5th parameter)
  3914. ** of the [sqlite3_create_function()]
  3915. ** and [sqlite3_create_function16()] routines that originally
  3916. ** registered the application defined function.
  3917. **
  3918. ** This routine must be called from the same thread in which
  3919. ** the application-defined function is running.
  3920. */
  3921. SQLITE_API void *sqlite3_user_data(sqlite3_context*);
  3922. /*
  3923. ** CAPI3REF: Database Connection For Functions
  3924. **
  3925. ** ^The sqlite3_context_db_handle() interface returns a copy of
  3926. ** the pointer to the [database connection] (the 1st parameter)
  3927. ** of the [sqlite3_create_function()]
  3928. ** and [sqlite3_create_function16()] routines that originally
  3929. ** registered the application defined function.
  3930. */
  3931. SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
  3932. /*
  3933. ** CAPI3REF: Function Auxiliary Data
  3934. **
  3935. ** The following two functions may be used by scalar SQL functions to
  3936. ** associate metadata with argument values. If the same value is passed to
  3937. ** multiple invocations of the same SQL function during query execution, under
  3938. ** some circumstances the associated metadata may be preserved. This may
  3939. ** be used, for example, to add a regular-expression matching scalar
  3940. ** function. The compiled version of the regular expression is stored as
  3941. ** metadata associated with the SQL value passed as the regular expression
  3942. ** pattern. The compiled regular expression can be reused on multiple
  3943. ** invocations of the same function so that the original pattern string
  3944. ** does not need to be recompiled on each invocation.
  3945. **
  3946. ** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata
  3947. ** associated by the sqlite3_set_auxdata() function with the Nth argument
  3948. ** value to the application-defined function. ^If no metadata has been ever
  3949. ** been set for the Nth argument of the function, or if the corresponding
  3950. ** function parameter has changed since the meta-data was set,
  3951. ** then sqlite3_get_auxdata() returns a NULL pointer.
  3952. **
  3953. ** ^The sqlite3_set_auxdata() interface saves the metadata
  3954. ** pointed to by its 3rd parameter as the metadata for the N-th
  3955. ** argument of the application-defined function. Subsequent
  3956. ** calls to sqlite3_get_auxdata() might return this data, if it has
  3957. ** not been destroyed.
  3958. ** ^If it is not NULL, SQLite will invoke the destructor
  3959. ** function given by the 4th parameter to sqlite3_set_auxdata() on
  3960. ** the metadata when the corresponding function parameter changes
  3961. ** or when the SQL statement completes, whichever comes first.
  3962. **
  3963. ** SQLite is free to call the destructor and drop metadata on any
  3964. ** parameter of any function at any time. ^The only guarantee is that
  3965. ** the destructor will be called before the metadata is dropped.
  3966. **
  3967. ** ^(In practice, metadata is preserved between function calls for
  3968. ** expressions that are constant at compile time. This includes literal
  3969. ** values and [parameters].)^
  3970. **
  3971. ** These routines must be called from the same thread in which
  3972. ** the SQL function is running.
  3973. */
  3974. SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N);
  3975. SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
  3976. /*
  3977. ** CAPI3REF: Constants Defining Special Destructor Behavior
  3978. **
  3979. ** These are special values for the destructor that is passed in as the
  3980. ** final argument to routines like [sqlite3_result_blob()]. ^If the destructor
  3981. ** argument is SQLITE_STATIC, it means that the content pointer is constant
  3982. ** and will never change. It does not need to be destroyed. ^The
  3983. ** SQLITE_TRANSIENT value means that the content will likely change in
  3984. ** the near future and that SQLite should make its own private copy of
  3985. ** the content before returning.
  3986. **
  3987. ** The typedef is necessary to work around problems in certain
  3988. ** C++ compilers. See ticket #2191.
  3989. */
  3990. typedef void (*sqlite3_destructor_type)(void*);
  3991. #define SQLITE_STATIC ((sqlite3_destructor_type)0)
  3992. #define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1)
  3993. /*
  3994. ** CAPI3REF: Setting The Result Of An SQL Function
  3995. **
  3996. ** These routines are used by the xFunc or xFinal callbacks that
  3997. ** implement SQL functions and aggregates. See
  3998. ** [sqlite3_create_function()] and [sqlite3_create_function16()]
  3999. ** for additional information.
  4000. **
  4001. ** These functions work very much like the [parameter binding] family of
  4002. ** functions used to bind values to host parameters in prepared statements.
  4003. ** Refer to the [SQL parameter] documentation for additional information.
  4004. **
  4005. ** ^The sqlite3_result_blob() interface sets the result from
  4006. ** an application-defined function to be the BLOB whose content is pointed
  4007. ** to by the second parameter and which is N bytes long where N is the
  4008. ** third parameter.
  4009. **
  4010. ** ^The sqlite3_result_zeroblob() interfaces set the result of
  4011. ** the application-defined function to be a BLOB containing all zero
  4012. ** bytes and N bytes in size, where N is the value of the 2nd parameter.
  4013. **
  4014. ** ^The sqlite3_result_double() interface sets the result from
  4015. ** an application-defined function to be a floating point value specified
  4016. ** by its 2nd argument.
  4017. **
  4018. ** ^The sqlite3_result_error() and sqlite3_result_error16() functions
  4019. ** cause the implemented SQL function to throw an exception.
  4020. ** ^SQLite uses the string pointed to by the
  4021. ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
  4022. ** as the text of an error message. ^SQLite interprets the error
  4023. ** message string from sqlite3_result_error() as UTF-8. ^SQLite
  4024. ** interprets the string from sqlite3_result_error16() as UTF-16 in native
  4025. ** byte order. ^If the third parameter to sqlite3_result_error()
  4026. ** or sqlite3_result_error16() is negative then SQLite takes as the error
  4027. ** message all text up through the first zero character.
  4028. ** ^If the third parameter to sqlite3_result_error() or
  4029. ** sqlite3_result_error16() is non-negative then SQLite takes that many
  4030. ** bytes (not characters) from the 2nd parameter as the error message.
  4031. ** ^The sqlite3_result_error() and sqlite3_result_error16()
  4032. ** routines make a private copy of the error message text before
  4033. ** they return. Hence, the calling function can deallocate or
  4034. ** modify the text after they return without harm.
  4035. ** ^The sqlite3_result_error_code() function changes the error code
  4036. ** returned by SQLite as a result of an error in a function. ^By default,
  4037. ** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error()
  4038. ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
  4039. **
  4040. ** ^The sqlite3_result_toobig() interface causes SQLite to throw an error
  4041. ** indicating that a string or BLOB is too long to represent.
  4042. **
  4043. ** ^The sqlite3_result_nomem() interface causes SQLite to throw an error
  4044. ** indicating that a memory allocation failed.
  4045. **
  4046. ** ^The sqlite3_result_int() interface sets the return value
  4047. ** of the application-defined function to be the 32-bit signed integer
  4048. ** value given in the 2nd argument.
  4049. ** ^The sqlite3_result_int64() interface sets the return value
  4050. ** of the application-defined function to be the 64-bit signed integer
  4051. ** value given in the 2nd argument.
  4052. **
  4053. ** ^The sqlite3_result_null() interface sets the return value
  4054. ** of the application-defined function to be NULL.
  4055. **
  4056. ** ^The sqlite3_result_text(), sqlite3_result_text16(),
  4057. ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
  4058. ** set the return value of the application-defined function to be
  4059. ** a text string which is represented as UTF-8, UTF-16 native byte order,
  4060. ** UTF-16 little endian, or UTF-16 big endian, respectively.
  4061. ** ^SQLite takes the text result from the application from
  4062. ** the 2nd parameter of the sqlite3_result_text* interfaces.
  4063. ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
  4064. ** is negative, then SQLite takes result text from the 2nd parameter
  4065. ** through the first zero character.
  4066. ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
  4067. ** is non-negative, then as many bytes (not characters) of the text
  4068. ** pointed to by the 2nd parameter are taken as the application-defined
  4069. ** function result. If the 3rd parameter is non-negative, then it
  4070. ** must be the byte offset into the string where the NUL terminator would
  4071. ** appear if the string where NUL terminated. If any NUL characters occur
  4072. ** in the string at a byte offset that is less than the value of the 3rd
  4073. ** parameter, then the resulting string will contain embedded NULs and the
  4074. ** result of expressions operating on strings with embedded NULs is undefined.
  4075. ** ^If the 4th parameter to the sqlite3_result_text* interfaces
  4076. ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
  4077. ** function as the destructor on the text or BLOB result when it has
  4078. ** finished using that result.
  4079. ** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
  4080. ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
  4081. ** assumes that the text or BLOB result is in constant space and does not
  4082. ** copy the content of the parameter nor call a destructor on the content
  4083. ** when it has finished using that result.
  4084. ** ^If the 4th parameter to the sqlite3_result_text* interfaces
  4085. ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
  4086. ** then SQLite makes a copy of the result into space obtained from
  4087. ** from [sqlite3_malloc()] before it returns.
  4088. **
  4089. ** ^The sqlite3_result_value() interface sets the result of
  4090. ** the application-defined function to be a copy the
  4091. ** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The
  4092. ** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
  4093. ** so that the [sqlite3_value] specified in the parameter may change or
  4094. ** be deallocated after sqlite3_result_value() returns without harm.
  4095. ** ^A [protected sqlite3_value] object may always be used where an
  4096. ** [unprotected sqlite3_value] object is required, so either
  4097. ** kind of [sqlite3_value] object can be used with this interface.
  4098. **
  4099. ** If these routines are called from within the different thread
  4100. ** than the one containing the application-defined function that received
  4101. ** the [sqlite3_context] pointer, the results are undefined.
  4102. */
  4103. SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
  4104. SQLITE_API void sqlite3_result_double(sqlite3_context*, double);
  4105. SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int);
  4106. SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int);
  4107. SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*);
  4108. SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*);
  4109. SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int);
  4110. SQLITE_API void sqlite3_result_int(sqlite3_context*, int);
  4111. SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
  4112. SQLITE_API void sqlite3_result_null(sqlite3_context*);
  4113. SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
  4114. SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
  4115. SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
  4116. SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
  4117. SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
  4118. SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n);
  4119. /*
  4120. ** CAPI3REF: Define New Collating Sequences
  4121. **
  4122. ** ^These functions add, remove, or modify a [collation] associated
  4123. ** with the [database connection] specified as the first argument.
  4124. **
  4125. ** ^The name of the collation is a UTF-8 string
  4126. ** for sqlite3_create_collation() and sqlite3_create_collation_v2()
  4127. ** and a UTF-16 string in native byte order for sqlite3_create_collation16().
  4128. ** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
  4129. ** considered to be the same name.
  4130. **
  4131. ** ^(The third argument (eTextRep) must be one of the constants:
  4132. ** <ul>
  4133. ** <li> [SQLITE_UTF8],
  4134. ** <li> [SQLITE_UTF16LE],
  4135. ** <li> [SQLITE_UTF16BE],
  4136. ** <li> [SQLITE_UTF16], or
  4137. ** <li> [SQLITE_UTF16_ALIGNED].
  4138. ** </ul>)^
  4139. ** ^The eTextRep argument determines the encoding of strings passed
  4140. ** to the collating function callback, xCallback.
  4141. ** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
  4142. ** force strings to be UTF16 with native byte order.
  4143. ** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
  4144. ** on an even byte address.
  4145. **
  4146. ** ^The fourth argument, pArg, is an application data pointer that is passed
  4147. ** through as the first argument to the collating function callback.
  4148. **
  4149. ** ^The fifth argument, xCallback, is a pointer to the collating function.
  4150. ** ^Multiple collating functions can be registered using the same name but
  4151. ** with different eTextRep parameters and SQLite will use whichever
  4152. ** function requires the least amount of data transformation.
  4153. ** ^If the xCallback argument is NULL then the collating function is
  4154. ** deleted. ^When all collating functions having the same name are deleted,
  4155. ** that collation is no longer usable.
  4156. **
  4157. ** ^The collating function callback is invoked with a copy of the pArg
  4158. ** application data pointer and with two strings in the encoding specified
  4159. ** by the eTextRep argument. The collating function must return an
  4160. ** integer that is negative, zero, or positive
  4161. ** if the first string is less than, equal to, or greater than the second,
  4162. ** respectively. A collating function must always return the same answer
  4163. ** given the same inputs. If two or more collating functions are registered
  4164. ** to the same collation name (using different eTextRep values) then all
  4165. ** must give an equivalent answer when invoked with equivalent strings.
  4166. ** The collating function must obey the following properties for all
  4167. ** strings A, B, and C:
  4168. **
  4169. ** <ol>
  4170. ** <li> If A==B then B==A.
  4171. ** <li> If A==B and B==C then A==C.
  4172. ** <li> If A&lt;B THEN B&gt;A.
  4173. ** <li> If A&lt;B and B&lt;C then A&lt;C.
  4174. ** </ol>
  4175. **
  4176. ** If a collating function fails any of the above constraints and that
  4177. ** collating function is registered and used, then the behavior of SQLite
  4178. ** is undefined.
  4179. **
  4180. ** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
  4181. ** with the addition that the xDestroy callback is invoked on pArg when
  4182. ** the collating function is deleted.
  4183. ** ^Collating functions are deleted when they are overridden by later
  4184. ** calls to the collation creation functions or when the
  4185. ** [database connection] is closed using [sqlite3_close()].
  4186. **
  4187. ** ^The xDestroy callback is <u>not</u> called if the
  4188. ** sqlite3_create_collation_v2() function fails. Applications that invoke
  4189. ** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
  4190. ** check the return code and dispose of the application data pointer
  4191. ** themselves rather than expecting SQLite to deal with it for them.
  4192. ** This is different from every other SQLite interface. The inconsistency
  4193. ** is unfortunate but cannot be changed without breaking backwards
  4194. ** compatibility.
  4195. **
  4196. ** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
  4197. */
  4198. SQLITE_API int sqlite3_create_collation(
  4199. sqlite3*,
  4200. const char *zName,
  4201. int eTextRep,
  4202. void *pArg,
  4203. int(*xCompare)(void*,int,const void*,int,const void*)
  4204. );
  4205. SQLITE_API int sqlite3_create_collation_v2(
  4206. sqlite3*,
  4207. const char *zName,
  4208. int eTextRep,
  4209. void *pArg,
  4210. int(*xCompare)(void*,int,const void*,int,const void*),
  4211. void(*xDestroy)(void*)
  4212. );
  4213. SQLITE_API int sqlite3_create_collation16(
  4214. sqlite3*,
  4215. const void *zName,
  4216. int eTextRep,
  4217. void *pArg,
  4218. int(*xCompare)(void*,int,const void*,int,const void*)
  4219. );
  4220. /*
  4221. ** CAPI3REF: Collation Needed Callbacks
  4222. **
  4223. ** ^To avoid having to register all collation sequences before a database
  4224. ** can be used, a single callback function may be registered with the
  4225. ** [database connection] to be invoked whenever an undefined collation
  4226. ** sequence is required.
  4227. **
  4228. ** ^If the function is registered using the sqlite3_collation_needed() API,
  4229. ** then it is passed the names of undefined collation sequences as strings
  4230. ** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
  4231. ** the names are passed as UTF-16 in machine native byte order.
  4232. ** ^A call to either function replaces the existing collation-needed callback.
  4233. **
  4234. ** ^(When the callback is invoked, the first argument passed is a copy
  4235. ** of the second argument to sqlite3_collation_needed() or
  4236. ** sqlite3_collation_needed16(). The second argument is the database
  4237. ** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
  4238. ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
  4239. ** sequence function required. The fourth parameter is the name of the
  4240. ** required collation sequence.)^
  4241. **
  4242. ** The callback function should register the desired collation using
  4243. ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
  4244. ** [sqlite3_create_collation_v2()].
  4245. */
  4246. SQLITE_API int sqlite3_collation_needed(
  4247. sqlite3*,
  4248. void*,
  4249. void(*)(void*,sqlite3*,int eTextRep,const char*)
  4250. );
  4251. SQLITE_API int sqlite3_collation_needed16(
  4252. sqlite3*,
  4253. void*,
  4254. void(*)(void*,sqlite3*,int eTextRep,const void*)
  4255. );
  4256. #ifdef SQLITE_HAS_CODEC
  4257. /*
  4258. ** Specify the key for an encrypted database. This routine should be
  4259. ** called right after sqlite3_open().
  4260. **
  4261. ** The code to implement this API is not available in the public release
  4262. ** of SQLite.
  4263. */
  4264. SQLITE_API int sqlite3_key(
  4265. sqlite3 *db, /* Database to be rekeyed */
  4266. const void *pKey, int nKey /* The key */
  4267. );
  4268. /*
  4269. ** Change the key on an open database. If the current database is not
  4270. ** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the
  4271. ** database is decrypted.
  4272. **
  4273. ** The code to implement this API is not available in the public release
  4274. ** of SQLite.
  4275. */
  4276. SQLITE_API int sqlite3_rekey(
  4277. sqlite3 *db, /* Database to be rekeyed */
  4278. const void *pKey, int nKey /* The new key */
  4279. );
  4280. /*
  4281. ** Specify the activation key for a SEE database. Unless
  4282. ** activated, none of the SEE routines will work.
  4283. */
  4284. SQLITE_API void sqlite3_activate_see(
  4285. const char *zPassPhrase /* Activation phrase */
  4286. );
  4287. #endif
  4288. #ifdef SQLITE_ENABLE_CEROD
  4289. /*
  4290. ** Specify the activation key for a CEROD database. Unless
  4291. ** activated, none of the CEROD routines will work.
  4292. */
  4293. SQLITE_API void sqlite3_activate_cerod(
  4294. const char *zPassPhrase /* Activation phrase */
  4295. );
  4296. #endif
  4297. /*
  4298. ** CAPI3REF: Suspend Execution For A Short Time
  4299. **
  4300. ** The sqlite3_sleep() function causes the current thread to suspend execution
  4301. ** for at least a number of milliseconds specified in its parameter.
  4302. **
  4303. ** If the operating system does not support sleep requests with
  4304. ** millisecond time resolution, then the time will be rounded up to
  4305. ** the nearest second. The number of milliseconds of sleep actually
  4306. ** requested from the operating system is returned.
  4307. **
  4308. ** ^SQLite implements this interface by calling the xSleep()
  4309. ** method of the default [sqlite3_vfs] object. If the xSleep() method
  4310. ** of the default VFS is not implemented correctly, or not implemented at
  4311. ** all, then the behavior of sqlite3_sleep() may deviate from the description
  4312. ** in the previous paragraphs.
  4313. */
  4314. SQLITE_API int sqlite3_sleep(int);
  4315. /*
  4316. ** CAPI3REF: Name Of The Folder Holding Temporary Files
  4317. **
  4318. ** ^(If this global variable is made to point to a string which is
  4319. ** the name of a folder (a.k.a. directory), then all temporary files
  4320. ** created by SQLite when using a built-in [sqlite3_vfs | VFS]
  4321. ** will be placed in that directory.)^ ^If this variable
  4322. ** is a NULL pointer, then SQLite performs a search for an appropriate
  4323. ** temporary file directory.
  4324. **
  4325. ** It is not safe to read or modify this variable in more than one
  4326. ** thread at a time. It is not safe to read or modify this variable
  4327. ** if a [database connection] is being used at the same time in a separate
  4328. ** thread.
  4329. ** It is intended that this variable be set once
  4330. ** as part of process initialization and before any SQLite interface
  4331. ** routines have been called and that this variable remain unchanged
  4332. ** thereafter.
  4333. **
  4334. ** ^The [temp_store_directory pragma] may modify this variable and cause
  4335. ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,
  4336. ** the [temp_store_directory pragma] always assumes that any string
  4337. ** that this variable points to is held in memory obtained from
  4338. ** [sqlite3_malloc] and the pragma may attempt to free that memory
  4339. ** using [sqlite3_free].
  4340. ** Hence, if this variable is modified directly, either it should be
  4341. ** made NULL or made to point to memory obtained from [sqlite3_malloc]
  4342. ** or else the use of the [temp_store_directory pragma] should be avoided.
  4343. */
  4344. SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory;
  4345. /*
  4346. ** CAPI3REF: Test For Auto-Commit Mode
  4347. ** KEYWORDS: {autocommit mode}
  4348. **
  4349. ** ^The sqlite3_get_autocommit() interface returns non-zero or
  4350. ** zero if the given database connection is or is not in autocommit mode,
  4351. ** respectively. ^Autocommit mode is on by default.
  4352. ** ^Autocommit mode is disabled by a [BEGIN] statement.
  4353. ** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
  4354. **
  4355. ** If certain kinds of errors occur on a statement within a multi-statement
  4356. ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
  4357. ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
  4358. ** transaction might be rolled back automatically. The only way to
  4359. ** find out whether SQLite automatically rolled back the transaction after
  4360. ** an error is to use this function.
  4361. **
  4362. ** If another thread changes the autocommit status of the database
  4363. ** connection while this routine is running, then the return value
  4364. ** is undefined.
  4365. */
  4366. SQLITE_API int sqlite3_get_autocommit(sqlite3*);
  4367. /*
  4368. ** CAPI3REF: Find The Database Handle Of A Prepared Statement
  4369. **
  4370. ** ^The sqlite3_db_handle interface returns the [database connection] handle
  4371. ** to which a [prepared statement] belongs. ^The [database connection]
  4372. ** returned by sqlite3_db_handle is the same [database connection]
  4373. ** that was the first argument
  4374. ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
  4375. ** create the statement in the first place.
  4376. */
  4377. SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
  4378. /*
  4379. ** CAPI3REF: Return The Filename For A Database Connection
  4380. **
  4381. ** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename
  4382. ** associated with database N of connection D. ^The main database file
  4383. ** has the name "main". If there is no attached database N on the database
  4384. ** connection D, or if database N is a temporary or in-memory database, then
  4385. ** a NULL pointer is returned.
  4386. **
  4387. ** ^The filename returned by this function is the output of the
  4388. ** xFullPathname method of the [VFS]. ^In other words, the filename
  4389. ** will be an absolute pathname, even if the filename used
  4390. ** to open the database originally was a URI or relative pathname.
  4391. */
  4392. SQLITE_API const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName);
  4393. /*
  4394. ** CAPI3REF: Determine if a database is read-only
  4395. **
  4396. ** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N
  4397. ** of connection D is read-only, 0 if it is read/write, or -1 if N is not
  4398. ** the name of a database on connection D.
  4399. */
  4400. SQLITE_API int sqlite3_db_readonly(sqlite3 *db, const char *zDbName);
  4401. /*
  4402. ** CAPI3REF: Find the next prepared statement
  4403. **
  4404. ** ^This interface returns a pointer to the next [prepared statement] after
  4405. ** pStmt associated with the [database connection] pDb. ^If pStmt is NULL
  4406. ** then this interface returns a pointer to the first prepared statement
  4407. ** associated with the database connection pDb. ^If no prepared statement
  4408. ** satisfies the conditions of this routine, it returns NULL.
  4409. **
  4410. ** The [database connection] pointer D in a call to
  4411. ** [sqlite3_next_stmt(D,S)] must refer to an open database
  4412. ** connection and in particular must not be a NULL pointer.
  4413. */
  4414. SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
  4415. /*
  4416. ** CAPI3REF: Commit And Rollback Notification Callbacks
  4417. **
  4418. ** ^The sqlite3_commit_hook() interface registers a callback
  4419. ** function to be invoked whenever a transaction is [COMMIT | committed].
  4420. ** ^Any callback set by a previous call to sqlite3_commit_hook()
  4421. ** for the same database connection is overridden.
  4422. ** ^The sqlite3_rollback_hook() interface registers a callback
  4423. ** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
  4424. ** ^Any callback set by a previous call to sqlite3_rollback_hook()
  4425. ** for the same database connection is overridden.
  4426. ** ^The pArg argument is passed through to the callback.
  4427. ** ^If the callback on a commit hook function returns non-zero,
  4428. ** then the commit is converted into a rollback.
  4429. **
  4430. ** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
  4431. ** return the P argument from the previous call of the same function
  4432. ** on the same [database connection] D, or NULL for
  4433. ** the first call for each function on D.
  4434. **
  4435. ** The commit and rollback hook callbacks are not reentrant.
  4436. ** The callback implementation must not do anything that will modify
  4437. ** the database connection that invoked the callback. Any actions
  4438. ** to modify the database connection must be deferred until after the
  4439. ** completion of the [sqlite3_step()] call that triggered the commit
  4440. ** or rollback hook in the first place.
  4441. ** Note that running any other SQL statements, including SELECT statements,
  4442. ** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
  4443. ** the database connections for the meaning of "modify" in this paragraph.
  4444. **
  4445. ** ^Registering a NULL function disables the callback.
  4446. **
  4447. ** ^When the commit hook callback routine returns zero, the [COMMIT]
  4448. ** operation is allowed to continue normally. ^If the commit hook
  4449. ** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
  4450. ** ^The rollback hook is invoked on a rollback that results from a commit
  4451. ** hook returning non-zero, just as it would be with any other rollback.
  4452. **
  4453. ** ^For the purposes of this API, a transaction is said to have been
  4454. ** rolled back if an explicit "ROLLBACK" statement is executed, or
  4455. ** an error or constraint causes an implicit rollback to occur.
  4456. ** ^The rollback callback is not invoked if a transaction is
  4457. ** automatically rolled back because the database connection is closed.
  4458. **
  4459. ** See also the [sqlite3_update_hook()] interface.
  4460. */
  4461. SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
  4462. SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
  4463. /*
  4464. ** CAPI3REF: Data Change Notification Callbacks
  4465. **
  4466. ** ^The sqlite3_update_hook() interface registers a callback function
  4467. ** with the [database connection] identified by the first argument
  4468. ** to be invoked whenever a row is updated, inserted or deleted.
  4469. ** ^Any callback set by a previous call to this function
  4470. ** for the same database connection is overridden.
  4471. **
  4472. ** ^The second argument is a pointer to the function to invoke when a
  4473. ** row is updated, inserted or deleted.
  4474. ** ^The first argument to the callback is a copy of the third argument
  4475. ** to sqlite3_update_hook().
  4476. ** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
  4477. ** or [SQLITE_UPDATE], depending on the operation that caused the callback
  4478. ** to be invoked.
  4479. ** ^The third and fourth arguments to the callback contain pointers to the
  4480. ** database and table name containing the affected row.
  4481. ** ^The final callback parameter is the [rowid] of the row.
  4482. ** ^In the case of an update, this is the [rowid] after the update takes place.
  4483. **
  4484. ** ^(The update hook is not invoked when internal system tables are
  4485. ** modified (i.e. sqlite_master and sqlite_sequence).)^
  4486. **
  4487. ** ^In the current implementation, the update hook
  4488. ** is not invoked when duplication rows are deleted because of an
  4489. ** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook
  4490. ** invoked when rows are deleted using the [truncate optimization].
  4491. ** The exceptions defined in this paragraph might change in a future
  4492. ** release of SQLite.
  4493. **
  4494. ** The update hook implementation must not do anything that will modify
  4495. ** the database connection that invoked the update hook. Any actions
  4496. ** to modify the database connection must be deferred until after the
  4497. ** completion of the [sqlite3_step()] call that triggered the update hook.
  4498. ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
  4499. ** database connections for the meaning of "modify" in this paragraph.
  4500. **
  4501. ** ^The sqlite3_update_hook(D,C,P) function
  4502. ** returns the P argument from the previous call
  4503. ** on the same [database connection] D, or NULL for
  4504. ** the first call on D.
  4505. **
  4506. ** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()]
  4507. ** interfaces.
  4508. */
  4509. SQLITE_API void *sqlite3_update_hook(
  4510. sqlite3*,
  4511. void(*)(void *,int ,char const *,char const *,sqlite3_int64),
  4512. void*
  4513. );
  4514. /*
  4515. ** CAPI3REF: Enable Or Disable Shared Pager Cache
  4516. ** KEYWORDS: {shared cache}
  4517. **
  4518. ** ^(This routine enables or disables the sharing of the database cache
  4519. ** and schema data structures between [database connection | connections]
  4520. ** to the same database. Sharing is enabled if the argument is true
  4521. ** and disabled if the argument is false.)^
  4522. **
  4523. ** ^Cache sharing is enabled and disabled for an entire process.
  4524. ** This is a change as of SQLite version 3.5.0. In prior versions of SQLite,
  4525. ** sharing was enabled or disabled for each thread separately.
  4526. **
  4527. ** ^(The cache sharing mode set by this interface effects all subsequent
  4528. ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
  4529. ** Existing database connections continue use the sharing mode
  4530. ** that was in effect at the time they were opened.)^
  4531. **
  4532. ** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
  4533. ** successfully. An [error code] is returned otherwise.)^
  4534. **
  4535. ** ^Shared cache is disabled by default. But this might change in
  4536. ** future releases of SQLite. Applications that care about shared
  4537. ** cache setting should set it explicitly.
  4538. **
  4539. ** See Also: [SQLite Shared-Cache Mode]
  4540. */
  4541. SQLITE_API int sqlite3_enable_shared_cache(int);
  4542. /*
  4543. ** CAPI3REF: Attempt To Free Heap Memory
  4544. **
  4545. ** ^The sqlite3_release_memory() interface attempts to free N bytes
  4546. ** of heap memory by deallocating non-essential memory allocations
  4547. ** held by the database library. Memory used to cache database
  4548. ** pages to improve performance is an example of non-essential memory.
  4549. ** ^sqlite3_release_memory() returns the number of bytes actually freed,
  4550. ** which might be more or less than the amount requested.
  4551. ** ^The sqlite3_release_memory() routine is a no-op returning zero
  4552. ** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
  4553. **
  4554. ** See also: [sqlite3_db_release_memory()]
  4555. */
  4556. SQLITE_API int sqlite3_release_memory(int);
  4557. /*
  4558. ** CAPI3REF: Free Memory Used By A Database Connection
  4559. **
  4560. ** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap
  4561. ** memory as possible from database connection D. Unlike the
  4562. ** [sqlite3_release_memory()] interface, this interface is effect even
  4563. ** when then [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
  4564. ** omitted.
  4565. **
  4566. ** See also: [sqlite3_release_memory()]
  4567. */
  4568. SQLITE_API int sqlite3_db_release_memory(sqlite3*);
  4569. /*
  4570. ** CAPI3REF: Impose A Limit On Heap Size
  4571. **
  4572. ** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
  4573. ** soft limit on the amount of heap memory that may be allocated by SQLite.
  4574. ** ^SQLite strives to keep heap memory utilization below the soft heap
  4575. ** limit by reducing the number of pages held in the page cache
  4576. ** as heap memory usages approaches the limit.
  4577. ** ^The soft heap limit is "soft" because even though SQLite strives to stay
  4578. ** below the limit, it will exceed the limit rather than generate
  4579. ** an [SQLITE_NOMEM] error. In other words, the soft heap limit
  4580. ** is advisory only.
  4581. **
  4582. ** ^The return value from sqlite3_soft_heap_limit64() is the size of
  4583. ** the soft heap limit prior to the call, or negative in the case of an
  4584. ** error. ^If the argument N is negative
  4585. ** then no change is made to the soft heap limit. Hence, the current
  4586. ** size of the soft heap limit can be determined by invoking
  4587. ** sqlite3_soft_heap_limit64() with a negative argument.
  4588. **
  4589. ** ^If the argument N is zero then the soft heap limit is disabled.
  4590. **
  4591. ** ^(The soft heap limit is not enforced in the current implementation
  4592. ** if one or more of following conditions are true:
  4593. **
  4594. ** <ul>
  4595. ** <li> The soft heap limit is set to zero.
  4596. ** <li> Memory accounting is disabled using a combination of the
  4597. ** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
  4598. ** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
  4599. ** <li> An alternative page cache implementation is specified using
  4600. ** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
  4601. ** <li> The page cache allocates from its own memory pool supplied
  4602. ** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
  4603. ** from the heap.
  4604. ** </ul>)^
  4605. **
  4606. ** Beginning with SQLite version 3.7.3, the soft heap limit is enforced
  4607. ** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT]
  4608. ** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT],
  4609. ** the soft heap limit is enforced on every memory allocation. Without
  4610. ** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced
  4611. ** when memory is allocated by the page cache. Testing suggests that because
  4612. ** the page cache is the predominate memory user in SQLite, most
  4613. ** applications will achieve adequate soft heap limit enforcement without
  4614. ** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT].
  4615. **
  4616. ** The circumstances under which SQLite will enforce the soft heap limit may
  4617. ** changes in future releases of SQLite.
  4618. */
  4619. SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);
  4620. /*
  4621. ** CAPI3REF: Deprecated Soft Heap Limit Interface
  4622. ** DEPRECATED
  4623. **
  4624. ** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
  4625. ** interface. This routine is provided for historical compatibility
  4626. ** only. All new applications should use the
  4627. ** [sqlite3_soft_heap_limit64()] interface rather than this one.
  4628. */
  4629. SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N);
  4630. /*
  4631. ** CAPI3REF: Extract Metadata About A Column Of A Table
  4632. **
  4633. ** ^This routine returns metadata about a specific column of a specific
  4634. ** database table accessible using the [database connection] handle
  4635. ** passed as the first function argument.
  4636. **
  4637. ** ^The column is identified by the second, third and fourth parameters to
  4638. ** this function. ^The second parameter is either the name of the database
  4639. ** (i.e. "main", "temp", or an attached database) containing the specified
  4640. ** table or NULL. ^If it is NULL, then all attached databases are searched
  4641. ** for the table using the same algorithm used by the database engine to
  4642. ** resolve unqualified table references.
  4643. **
  4644. ** ^The third and fourth parameters to this function are the table and column
  4645. ** name of the desired column, respectively. Neither of these parameters
  4646. ** may be NULL.
  4647. **
  4648. ** ^Metadata is returned by writing to the memory locations passed as the 5th
  4649. ** and subsequent parameters to this function. ^Any of these arguments may be
  4650. ** NULL, in which case the corresponding element of metadata is omitted.
  4651. **
  4652. ** ^(<blockquote>
  4653. ** <table border="1">
  4654. ** <tr><th> Parameter <th> Output<br>Type <th> Description
  4655. **
  4656. ** <tr><td> 5th <td> const char* <td> Data type
  4657. ** <tr><td> 6th <td> const char* <td> Name of default collation sequence
  4658. ** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint
  4659. ** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY
  4660. ** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT]
  4661. ** </table>
  4662. ** </blockquote>)^
  4663. **
  4664. ** ^The memory pointed to by the character pointers returned for the
  4665. ** declaration type and collation sequence is valid only until the next
  4666. ** call to any SQLite API function.
  4667. **
  4668. ** ^If the specified table is actually a view, an [error code] is returned.
  4669. **
  4670. ** ^If the specified column is "rowid", "oid" or "_rowid_" and an
  4671. ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
  4672. ** parameters are set for the explicitly declared column. ^(If there is no
  4673. ** explicitly declared [INTEGER PRIMARY KEY] column, then the output
  4674. ** parameters are set as follows:
  4675. **
  4676. ** <pre>
  4677. ** data type: "INTEGER"
  4678. ** collation sequence: "BINARY"
  4679. ** not null: 0
  4680. ** primary key: 1
  4681. ** auto increment: 0
  4682. ** </pre>)^
  4683. **
  4684. ** ^(This function may load one or more schemas from database files. If an
  4685. ** error occurs during this process, or if the requested table or column
  4686. ** cannot be found, an [error code] is returned and an error message left
  4687. ** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^
  4688. **
  4689. ** ^This API is only available if the library was compiled with the
  4690. ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined.
  4691. */
  4692. SQLITE_API int sqlite3_table_column_metadata(
  4693. sqlite3 *db, /* Connection handle */
  4694. const char *zDbName, /* Database name or NULL */
  4695. const char *zTableName, /* Table name */
  4696. const char *zColumnName, /* Column name */
  4697. char const **pzDataType, /* OUTPUT: Declared data type */
  4698. char const **pzCollSeq, /* OUTPUT: Collation sequence name */
  4699. int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */
  4700. int *pPrimaryKey, /* OUTPUT: True if column part of PK */
  4701. int *pAutoinc /* OUTPUT: True if column is auto-increment */
  4702. );
  4703. /*
  4704. ** CAPI3REF: Load An Extension
  4705. **
  4706. ** ^This interface loads an SQLite extension library from the named file.
  4707. **
  4708. ** ^The sqlite3_load_extension() interface attempts to load an
  4709. ** SQLite extension library contained in the file zFile.
  4710. **
  4711. ** ^The entry point is zProc.
  4712. ** ^zProc may be 0, in which case the name of the entry point
  4713. ** defaults to "sqlite3_extension_init".
  4714. ** ^The sqlite3_load_extension() interface returns
  4715. ** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
  4716. ** ^If an error occurs and pzErrMsg is not 0, then the
  4717. ** [sqlite3_load_extension()] interface shall attempt to
  4718. ** fill *pzErrMsg with error message text stored in memory
  4719. ** obtained from [sqlite3_malloc()]. The calling function
  4720. ** should free this memory by calling [sqlite3_free()].
  4721. **
  4722. ** ^Extension loading must be enabled using
  4723. ** [sqlite3_enable_load_extension()] prior to calling this API,
  4724. ** otherwise an error will be returned.
  4725. **
  4726. ** See also the [load_extension() SQL function].
  4727. */
  4728. SQLITE_API int sqlite3_load_extension(
  4729. sqlite3 *db, /* Load the extension into this database connection */
  4730. const char *zFile, /* Name of the shared library containing extension */
  4731. const char *zProc, /* Entry point. Derived from zFile if 0 */
  4732. char **pzErrMsg /* Put error message here if not 0 */
  4733. );
  4734. /*
  4735. ** CAPI3REF: Enable Or Disable Extension Loading
  4736. **
  4737. ** ^So as not to open security holes in older applications that are
  4738. ** unprepared to deal with extension loading, and as a means of disabling
  4739. ** extension loading while evaluating user-entered SQL, the following API
  4740. ** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
  4741. **
  4742. ** ^Extension loading is off by default. See ticket #1863.
  4743. ** ^Call the sqlite3_enable_load_extension() routine with onoff==1
  4744. ** to turn extension loading on and call it with onoff==0 to turn
  4745. ** it back off again.
  4746. */
  4747. SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
  4748. /*
  4749. ** CAPI3REF: Automatically Load Statically Linked Extensions
  4750. **
  4751. ** ^This interface causes the xEntryPoint() function to be invoked for
  4752. ** each new [database connection] that is created. The idea here is that
  4753. ** xEntryPoint() is the entry point for a statically linked SQLite extension
  4754. ** that is to be automatically loaded into all new database connections.
  4755. **
  4756. ** ^(Even though the function prototype shows that xEntryPoint() takes
  4757. ** no arguments and returns void, SQLite invokes xEntryPoint() with three
  4758. ** arguments and expects and integer result as if the signature of the
  4759. ** entry point where as follows:
  4760. **
  4761. ** <blockquote><pre>
  4762. ** &nbsp; int xEntryPoint(
  4763. ** &nbsp; sqlite3 *db,
  4764. ** &nbsp; const char **pzErrMsg,
  4765. ** &nbsp; const struct sqlite3_api_routines *pThunk
  4766. ** &nbsp; );
  4767. ** </pre></blockquote>)^
  4768. **
  4769. ** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
  4770. ** point to an appropriate error message (obtained from [sqlite3_mprintf()])
  4771. ** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg
  4772. ** is NULL before calling the xEntryPoint(). ^SQLite will invoke
  4773. ** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any
  4774. ** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
  4775. ** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
  4776. **
  4777. ** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
  4778. ** on the list of automatic extensions is a harmless no-op. ^No entry point
  4779. ** will be called more than once for each database connection that is opened.
  4780. **
  4781. ** See also: [sqlite3_reset_auto_extension()].
  4782. */
  4783. SQLITE_API int sqlite3_auto_extension(void (*xEntryPoint)(void));
  4784. /*
  4785. ** CAPI3REF: Reset Automatic Extension Loading
  4786. **
  4787. ** ^This interface disables all automatic extensions previously
  4788. ** registered using [sqlite3_auto_extension()].
  4789. */
  4790. SQLITE_API void sqlite3_reset_auto_extension(void);
  4791. /*
  4792. ** The interface to the virtual-table mechanism is currently considered
  4793. ** to be experimental. The interface might change in incompatible ways.
  4794. ** If this is a problem for you, do not use the interface at this time.
  4795. **
  4796. ** When the virtual-table mechanism stabilizes, we will declare the
  4797. ** interface fixed, support it indefinitely, and remove this comment.
  4798. */
  4799. /*
  4800. ** Structures used by the virtual table interface
  4801. */
  4802. typedef struct sqlite3_vtab sqlite3_vtab;
  4803. typedef struct sqlite3_index_info sqlite3_index_info;
  4804. typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
  4805. typedef struct sqlite3_module sqlite3_module;
  4806. /*
  4807. ** CAPI3REF: Virtual Table Object
  4808. ** KEYWORDS: sqlite3_module {virtual table module}
  4809. **
  4810. ** This structure, sometimes called a "virtual table module",
  4811. ** defines the implementation of a [virtual tables].
  4812. ** This structure consists mostly of methods for the module.
  4813. **
  4814. ** ^A virtual table module is created by filling in a persistent
  4815. ** instance of this structure and passing a pointer to that instance
  4816. ** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
  4817. ** ^The registration remains valid until it is replaced by a different
  4818. ** module or until the [database connection] closes. The content
  4819. ** of this structure must not change while it is registered with
  4820. ** any database connection.
  4821. */
  4822. struct sqlite3_module {
  4823. int iVersion;
  4824. int (*xCreate)(sqlite3*, void *pAux,
  4825. int argc, const char *const*argv,
  4826. sqlite3_vtab **ppVTab, char**);
  4827. int (*xConnect)(sqlite3*, void *pAux,
  4828. int argc, const char *const*argv,
  4829. sqlite3_vtab **ppVTab, char**);
  4830. int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
  4831. int (*xDisconnect)(sqlite3_vtab *pVTab);
  4832. int (*xDestroy)(sqlite3_vtab *pVTab);
  4833. int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
  4834. int (*xClose)(sqlite3_vtab_cursor*);
  4835. int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
  4836. int argc, sqlite3_value **argv);
  4837. int (*xNext)(sqlite3_vtab_cursor*);
  4838. int (*xEof)(sqlite3_vtab_cursor*);
  4839. int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
  4840. int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
  4841. int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
  4842. int (*xBegin)(sqlite3_vtab *pVTab);
  4843. int (*xSync)(sqlite3_vtab *pVTab);
  4844. int (*xCommit)(sqlite3_vtab *pVTab);
  4845. int (*xRollback)(sqlite3_vtab *pVTab);
  4846. int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
  4847. void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
  4848. void **ppArg);
  4849. int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
  4850. /* The methods above are in version 1 of the sqlite_module object. Those
  4851. ** below are for version 2 and greater. */
  4852. int (*xSavepoint)(sqlite3_vtab *pVTab, int);
  4853. int (*xRelease)(sqlite3_vtab *pVTab, int);
  4854. int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
  4855. };
  4856. /*
  4857. ** CAPI3REF: Virtual Table Indexing Information
  4858. ** KEYWORDS: sqlite3_index_info
  4859. **
  4860. ** The sqlite3_index_info structure and its substructures is used as part
  4861. ** of the [virtual table] interface to
  4862. ** pass information into and receive the reply from the [xBestIndex]
  4863. ** method of a [virtual table module]. The fields under **Inputs** are the
  4864. ** inputs to xBestIndex and are read-only. xBestIndex inserts its
  4865. ** results into the **Outputs** fields.
  4866. **
  4867. ** ^(The aConstraint[] array records WHERE clause constraints of the form:
  4868. **
  4869. ** <blockquote>column OP expr</blockquote>
  4870. **
  4871. ** where OP is =, &lt;, &lt;=, &gt;, or &gt;=.)^ ^(The particular operator is
  4872. ** stored in aConstraint[].op using one of the
  4873. ** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
  4874. ** ^(The index of the column is stored in
  4875. ** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the
  4876. ** expr on the right-hand side can be evaluated (and thus the constraint
  4877. ** is usable) and false if it cannot.)^
  4878. **
  4879. ** ^The optimizer automatically inverts terms of the form "expr OP column"
  4880. ** and makes other simplifications to the WHERE clause in an attempt to
  4881. ** get as many WHERE clause terms into the form shown above as possible.
  4882. ** ^The aConstraint[] array only reports WHERE clause terms that are
  4883. ** relevant to the particular virtual table being queried.
  4884. **
  4885. ** ^Information about the ORDER BY clause is stored in aOrderBy[].
  4886. ** ^Each term of aOrderBy records a column of the ORDER BY clause.
  4887. **
  4888. ** The [xBestIndex] method must fill aConstraintUsage[] with information
  4889. ** about what parameters to pass to xFilter. ^If argvIndex>0 then
  4890. ** the right-hand side of the corresponding aConstraint[] is evaluated
  4891. ** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit
  4892. ** is true, then the constraint is assumed to be fully handled by the
  4893. ** virtual table and is not checked again by SQLite.)^
  4894. **
  4895. ** ^The idxNum and idxPtr values are recorded and passed into the
  4896. ** [xFilter] method.
  4897. ** ^[sqlite3_free()] is used to free idxPtr if and only if
  4898. ** needToFreeIdxPtr is true.
  4899. **
  4900. ** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
  4901. ** the correct order to satisfy the ORDER BY clause so that no separate
  4902. ** sorting step is required.
  4903. **
  4904. ** ^The estimatedCost value is an estimate of the cost of doing the
  4905. ** particular lookup. A full scan of a table with N entries should have
  4906. ** a cost of N. A binary search of a table of N entries should have a
  4907. ** cost of approximately log(N).
  4908. */
  4909. struct sqlite3_index_info {
  4910. /* Inputs */
  4911. int nConstraint; /* Number of entries in aConstraint */
  4912. struct sqlite3_index_constraint {
  4913. int iColumn; /* Column on left-hand side of constraint */
  4914. unsigned char op; /* Constraint operator */
  4915. unsigned char usable; /* True if this constraint is usable */
  4916. int iTermOffset; /* Used internally - xBestIndex should ignore */
  4917. } *aConstraint; /* Table of WHERE clause constraints */
  4918. int nOrderBy; /* Number of terms in the ORDER BY clause */
  4919. struct sqlite3_index_orderby {
  4920. int iColumn; /* Column number */
  4921. unsigned char desc; /* True for DESC. False for ASC. */
  4922. } *aOrderBy; /* The ORDER BY clause */
  4923. /* Outputs */
  4924. struct sqlite3_index_constraint_usage {
  4925. int argvIndex; /* if >0, constraint is part of argv to xFilter */
  4926. unsigned char omit; /* Do not code a test for this constraint */
  4927. } *aConstraintUsage;
  4928. int idxNum; /* Number used to identify the index */
  4929. char *idxStr; /* String, possibly obtained from sqlite3_malloc */
  4930. int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */
  4931. int orderByConsumed; /* True if output is already ordered */
  4932. double estimatedCost; /* Estimated cost of using this index */
  4933. };
  4934. /*
  4935. ** CAPI3REF: Virtual Table Constraint Operator Codes
  4936. **
  4937. ** These macros defined the allowed values for the
  4938. ** [sqlite3_index_info].aConstraint[].op field. Each value represents
  4939. ** an operator that is part of a constraint term in the wHERE clause of
  4940. ** a query that uses a [virtual table].
  4941. */
  4942. #define SQLITE_INDEX_CONSTRAINT_EQ 2
  4943. #define SQLITE_INDEX_CONSTRAINT_GT 4
  4944. #define SQLITE_INDEX_CONSTRAINT_LE 8
  4945. #define SQLITE_INDEX_CONSTRAINT_LT 16
  4946. #define SQLITE_INDEX_CONSTRAINT_GE 32
  4947. #define SQLITE_INDEX_CONSTRAINT_MATCH 64
  4948. /*
  4949. ** CAPI3REF: Register A Virtual Table Implementation
  4950. **
  4951. ** ^These routines are used to register a new [virtual table module] name.
  4952. ** ^Module names must be registered before
  4953. ** creating a new [virtual table] using the module and before using a
  4954. ** preexisting [virtual table] for the module.
  4955. **
  4956. ** ^The module name is registered on the [database connection] specified
  4957. ** by the first parameter. ^The name of the module is given by the
  4958. ** second parameter. ^The third parameter is a pointer to
  4959. ** the implementation of the [virtual table module]. ^The fourth
  4960. ** parameter is an arbitrary client data pointer that is passed through
  4961. ** into the [xCreate] and [xConnect] methods of the virtual table module
  4962. ** when a new virtual table is be being created or reinitialized.
  4963. **
  4964. ** ^The sqlite3_create_module_v2() interface has a fifth parameter which
  4965. ** is a pointer to a destructor for the pClientData. ^SQLite will
  4966. ** invoke the destructor function (if it is not NULL) when SQLite
  4967. ** no longer needs the pClientData pointer. ^The destructor will also
  4968. ** be invoked if the call to sqlite3_create_module_v2() fails.
  4969. ** ^The sqlite3_create_module()
  4970. ** interface is equivalent to sqlite3_create_module_v2() with a NULL
  4971. ** destructor.
  4972. */
  4973. SQLITE_API int sqlite3_create_module(
  4974. sqlite3 *db, /* SQLite connection to register module with */
  4975. const char *zName, /* Name of the module */
  4976. const sqlite3_module *p, /* Methods for the module */
  4977. void *pClientData /* Client data for xCreate/xConnect */
  4978. );
  4979. SQLITE_API int sqlite3_create_module_v2(
  4980. sqlite3 *db, /* SQLite connection to register module with */
  4981. const char *zName, /* Name of the module */
  4982. const sqlite3_module *p, /* Methods for the module */
  4983. void *pClientData, /* Client data for xCreate/xConnect */
  4984. void(*xDestroy)(void*) /* Module destructor function */
  4985. );
  4986. /*
  4987. ** CAPI3REF: Virtual Table Instance Object
  4988. ** KEYWORDS: sqlite3_vtab
  4989. **
  4990. ** Every [virtual table module] implementation uses a subclass
  4991. ** of this object to describe a particular instance
  4992. ** of the [virtual table]. Each subclass will
  4993. ** be tailored to the specific needs of the module implementation.
  4994. ** The purpose of this superclass is to define certain fields that are
  4995. ** common to all module implementations.
  4996. **
  4997. ** ^Virtual tables methods can set an error message by assigning a
  4998. ** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should
  4999. ** take care that any prior string is freed by a call to [sqlite3_free()]
  5000. ** prior to assigning a new string to zErrMsg. ^After the error message
  5001. ** is delivered up to the client application, the string will be automatically
  5002. ** freed by sqlite3_free() and the zErrMsg field will be zeroed.
  5003. */
  5004. struct sqlite3_vtab {
  5005. const sqlite3_module *pModule; /* The module for this virtual table */
  5006. int nRef; /* NO LONGER USED */
  5007. char *zErrMsg; /* Error message from sqlite3_mprintf() */
  5008. /* Virtual table implementations will typically add additional fields */
  5009. };
  5010. /*
  5011. ** CAPI3REF: Virtual Table Cursor Object
  5012. ** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
  5013. **
  5014. ** Every [virtual table module] implementation uses a subclass of the
  5015. ** following structure to describe cursors that point into the
  5016. ** [virtual table] and are used
  5017. ** to loop through the virtual table. Cursors are created using the
  5018. ** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
  5019. ** by the [sqlite3_module.xClose | xClose] method. Cursors are used
  5020. ** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
  5021. ** of the module. Each module implementation will define
  5022. ** the content of a cursor structure to suit its own needs.
  5023. **
  5024. ** This superclass exists in order to define fields of the cursor that
  5025. ** are common to all implementations.
  5026. */
  5027. struct sqlite3_vtab_cursor {
  5028. sqlite3_vtab *pVtab; /* Virtual table of this cursor */
  5029. /* Virtual table implementations will typically add additional fields */
  5030. };
  5031. /*
  5032. ** CAPI3REF: Declare The Schema Of A Virtual Table
  5033. **
  5034. ** ^The [xCreate] and [xConnect] methods of a
  5035. ** [virtual table module] call this interface
  5036. ** to declare the format (the names and datatypes of the columns) of
  5037. ** the virtual tables they implement.
  5038. */
  5039. SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
  5040. /*
  5041. ** CAPI3REF: Overload A Function For A Virtual Table
  5042. **
  5043. ** ^(Virtual tables can provide alternative implementations of functions
  5044. ** using the [xFindFunction] method of the [virtual table module].
  5045. ** But global versions of those functions
  5046. ** must exist in order to be overloaded.)^
  5047. **
  5048. ** ^(This API makes sure a global version of a function with a particular
  5049. ** name and number of parameters exists. If no such function exists
  5050. ** before this API is called, a new function is created.)^ ^The implementation
  5051. ** of the new function always causes an exception to be thrown. So
  5052. ** the new function is not good for anything by itself. Its only
  5053. ** purpose is to be a placeholder function that can be overloaded
  5054. ** by a [virtual table].
  5055. */
  5056. SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
  5057. /*
  5058. ** The interface to the virtual-table mechanism defined above (back up
  5059. ** to a comment remarkably similar to this one) is currently considered
  5060. ** to be experimental. The interface might change in incompatible ways.
  5061. ** If this is a problem for you, do not use the interface at this time.
  5062. **
  5063. ** When the virtual-table mechanism stabilizes, we will declare the
  5064. ** interface fixed, support it indefinitely, and remove this comment.
  5065. */
  5066. /*
  5067. ** CAPI3REF: A Handle To An Open BLOB
  5068. ** KEYWORDS: {BLOB handle} {BLOB handles}
  5069. **
  5070. ** An instance of this object represents an open BLOB on which
  5071. ** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
  5072. ** ^Objects of this type are created by [sqlite3_blob_open()]
  5073. ** and destroyed by [sqlite3_blob_close()].
  5074. ** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
  5075. ** can be used to read or write small subsections of the BLOB.
  5076. ** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
  5077. */
  5078. typedef struct sqlite3_blob sqlite3_blob;
  5079. /*
  5080. ** CAPI3REF: Open A BLOB For Incremental I/O
  5081. **
  5082. ** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
  5083. ** in row iRow, column zColumn, table zTable in database zDb;
  5084. ** in other words, the same BLOB that would be selected by:
  5085. **
  5086. ** <pre>
  5087. ** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
  5088. ** </pre>)^
  5089. **
  5090. ** ^If the flags parameter is non-zero, then the BLOB is opened for read
  5091. ** and write access. ^If it is zero, the BLOB is opened for read access.
  5092. ** ^It is not possible to open a column that is part of an index or primary
  5093. ** key for writing. ^If [foreign key constraints] are enabled, it is
  5094. ** not possible to open a column that is part of a [child key] for writing.
  5095. **
  5096. ** ^Note that the database name is not the filename that contains
  5097. ** the database but rather the symbolic name of the database that
  5098. ** appears after the AS keyword when the database is connected using [ATTACH].
  5099. ** ^For the main database file, the database name is "main".
  5100. ** ^For TEMP tables, the database name is "temp".
  5101. **
  5102. ** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written
  5103. ** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set
  5104. ** to be a null pointer.)^
  5105. ** ^This function sets the [database connection] error code and message
  5106. ** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related
  5107. ** functions. ^Note that the *ppBlob variable is always initialized in a
  5108. ** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob
  5109. ** regardless of the success or failure of this routine.
  5110. **
  5111. ** ^(If the row that a BLOB handle points to is modified by an
  5112. ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
  5113. ** then the BLOB handle is marked as "expired".
  5114. ** This is true if any column of the row is changed, even a column
  5115. ** other than the one the BLOB handle is open on.)^
  5116. ** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
  5117. ** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
  5118. ** ^(Changes written into a BLOB prior to the BLOB expiring are not
  5119. ** rolled back by the expiration of the BLOB. Such changes will eventually
  5120. ** commit if the transaction continues to completion.)^
  5121. **
  5122. ** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
  5123. ** the opened blob. ^The size of a blob may not be changed by this
  5124. ** interface. Use the [UPDATE] SQL command to change the size of a
  5125. ** blob.
  5126. **
  5127. ** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
  5128. ** and the built-in [zeroblob] SQL function can be used, if desired,
  5129. ** to create an empty, zero-filled blob in which to read or write using
  5130. ** this interface.
  5131. **
  5132. ** To avoid a resource leak, every open [BLOB handle] should eventually
  5133. ** be released by a call to [sqlite3_blob_close()].
  5134. */
  5135. SQLITE_API int sqlite3_blob_open(
  5136. sqlite3*,
  5137. const char *zDb,
  5138. const char *zTable,
  5139. const char *zColumn,
  5140. sqlite3_int64 iRow,
  5141. int flags,
  5142. sqlite3_blob **ppBlob
  5143. );
  5144. /*
  5145. ** CAPI3REF: Move a BLOB Handle to a New Row
  5146. **
  5147. ** ^This function is used to move an existing blob handle so that it points
  5148. ** to a different row of the same database table. ^The new row is identified
  5149. ** by the rowid value passed as the second argument. Only the row can be
  5150. ** changed. ^The database, table and column on which the blob handle is open
  5151. ** remain the same. Moving an existing blob handle to a new row can be
  5152. ** faster than closing the existing handle and opening a new one.
  5153. **
  5154. ** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
  5155. ** it must exist and there must be either a blob or text value stored in
  5156. ** the nominated column.)^ ^If the new row is not present in the table, or if
  5157. ** it does not contain a blob or text value, or if another error occurs, an
  5158. ** SQLite error code is returned and the blob handle is considered aborted.
  5159. ** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
  5160. ** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
  5161. ** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
  5162. ** always returns zero.
  5163. **
  5164. ** ^This function sets the database handle error code and message.
  5165. */
  5166. SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
  5167. /*
  5168. ** CAPI3REF: Close A BLOB Handle
  5169. **
  5170. ** ^Closes an open [BLOB handle].
  5171. **
  5172. ** ^Closing a BLOB shall cause the current transaction to commit
  5173. ** if there are no other BLOBs, no pending prepared statements, and the
  5174. ** database connection is in [autocommit mode].
  5175. ** ^If any writes were made to the BLOB, they might be held in cache
  5176. ** until the close operation if they will fit.
  5177. **
  5178. ** ^(Closing the BLOB often forces the changes
  5179. ** out to disk and so if any I/O errors occur, they will likely occur
  5180. ** at the time when the BLOB is closed. Any errors that occur during
  5181. ** closing are reported as a non-zero return value.)^
  5182. **
  5183. ** ^(The BLOB is closed unconditionally. Even if this routine returns
  5184. ** an error code, the BLOB is still closed.)^
  5185. **
  5186. ** ^Calling this routine with a null pointer (such as would be returned
  5187. ** by a failed call to [sqlite3_blob_open()]) is a harmless no-op.
  5188. */
  5189. SQLITE_API int sqlite3_blob_close(sqlite3_blob *);
  5190. /*
  5191. ** CAPI3REF: Return The Size Of An Open BLOB
  5192. **
  5193. ** ^Returns the size in bytes of the BLOB accessible via the
  5194. ** successfully opened [BLOB handle] in its only argument. ^The
  5195. ** incremental blob I/O routines can only read or overwriting existing
  5196. ** blob content; they cannot change the size of a blob.
  5197. **
  5198. ** This routine only works on a [BLOB handle] which has been created
  5199. ** by a prior successful call to [sqlite3_blob_open()] and which has not
  5200. ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
  5201. ** to this routine results in undefined and probably undesirable behavior.
  5202. */
  5203. SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *);
  5204. /*
  5205. ** CAPI3REF: Read Data From A BLOB Incrementally
  5206. **
  5207. ** ^(This function is used to read data from an open [BLOB handle] into a
  5208. ** caller-supplied buffer. N bytes of data are copied into buffer Z
  5209. ** from the open BLOB, starting at offset iOffset.)^
  5210. **
  5211. ** ^If offset iOffset is less than N bytes from the end of the BLOB,
  5212. ** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is
  5213. ** less than zero, [SQLITE_ERROR] is returned and no data is read.
  5214. ** ^The size of the blob (and hence the maximum value of N+iOffset)
  5215. ** can be determined using the [sqlite3_blob_bytes()] interface.
  5216. **
  5217. ** ^An attempt to read from an expired [BLOB handle] fails with an
  5218. ** error code of [SQLITE_ABORT].
  5219. **
  5220. ** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
  5221. ** Otherwise, an [error code] or an [extended error code] is returned.)^
  5222. **
  5223. ** This routine only works on a [BLOB handle] which has been created
  5224. ** by a prior successful call to [sqlite3_blob_open()] and which has not
  5225. ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
  5226. ** to this routine results in undefined and probably undesirable behavior.
  5227. **
  5228. ** See also: [sqlite3_blob_write()].
  5229. */
  5230. SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
  5231. /*
  5232. ** CAPI3REF: Write Data Into A BLOB Incrementally
  5233. **
  5234. ** ^This function is used to write data into an open [BLOB handle] from a
  5235. ** caller-supplied buffer. ^N bytes of data are copied from the buffer Z
  5236. ** into the open BLOB, starting at offset iOffset.
  5237. **
  5238. ** ^If the [BLOB handle] passed as the first argument was not opened for
  5239. ** writing (the flags parameter to [sqlite3_blob_open()] was zero),
  5240. ** this function returns [SQLITE_READONLY].
  5241. **
  5242. ** ^This function may only modify the contents of the BLOB; it is
  5243. ** not possible to increase the size of a BLOB using this API.
  5244. ** ^If offset iOffset is less than N bytes from the end of the BLOB,
  5245. ** [SQLITE_ERROR] is returned and no data is written. ^If N is
  5246. ** less than zero [SQLITE_ERROR] is returned and no data is written.
  5247. ** The size of the BLOB (and hence the maximum value of N+iOffset)
  5248. ** can be determined using the [sqlite3_blob_bytes()] interface.
  5249. **
  5250. ** ^An attempt to write to an expired [BLOB handle] fails with an
  5251. ** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred
  5252. ** before the [BLOB handle] expired are not rolled back by the
  5253. ** expiration of the handle, though of course those changes might
  5254. ** have been overwritten by the statement that expired the BLOB handle
  5255. ** or by other independent statements.
  5256. **
  5257. ** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
  5258. ** Otherwise, an [error code] or an [extended error code] is returned.)^
  5259. **
  5260. ** This routine only works on a [BLOB handle] which has been created
  5261. ** by a prior successful call to [sqlite3_blob_open()] and which has not
  5262. ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
  5263. ** to this routine results in undefined and probably undesirable behavior.
  5264. **
  5265. ** See also: [sqlite3_blob_read()].
  5266. */
  5267. SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
  5268. /*
  5269. ** CAPI3REF: Virtual File System Objects
  5270. **
  5271. ** A virtual filesystem (VFS) is an [sqlite3_vfs] object
  5272. ** that SQLite uses to interact
  5273. ** with the underlying operating system. Most SQLite builds come with a
  5274. ** single default VFS that is appropriate for the host computer.
  5275. ** New VFSes can be registered and existing VFSes can be unregistered.
  5276. ** The following interfaces are provided.
  5277. **
  5278. ** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
  5279. ** ^Names are case sensitive.
  5280. ** ^Names are zero-terminated UTF-8 strings.
  5281. ** ^If there is no match, a NULL pointer is returned.
  5282. ** ^If zVfsName is NULL then the default VFS is returned.
  5283. **
  5284. ** ^New VFSes are registered with sqlite3_vfs_register().
  5285. ** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
  5286. ** ^The same VFS can be registered multiple times without injury.
  5287. ** ^To make an existing VFS into the default VFS, register it again
  5288. ** with the makeDflt flag set. If two different VFSes with the
  5289. ** same name are registered, the behavior is undefined. If a
  5290. ** VFS is registered with a name that is NULL or an empty string,
  5291. ** then the behavior is undefined.
  5292. **
  5293. ** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
  5294. ** ^(If the default VFS is unregistered, another VFS is chosen as
  5295. ** the default. The choice for the new VFS is arbitrary.)^
  5296. */
  5297. SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
  5298. SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
  5299. SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*);
  5300. /*
  5301. ** CAPI3REF: Mutexes
  5302. **
  5303. ** The SQLite core uses these routines for thread
  5304. ** synchronization. Though they are intended for internal
  5305. ** use by SQLite, code that links against SQLite is
  5306. ** permitted to use any of these routines.
  5307. **
  5308. ** The SQLite source code contains multiple implementations
  5309. ** of these mutex routines. An appropriate implementation
  5310. ** is selected automatically at compile-time. ^(The following
  5311. ** implementations are available in the SQLite core:
  5312. **
  5313. ** <ul>
  5314. ** <li> SQLITE_MUTEX_OS2
  5315. ** <li> SQLITE_MUTEX_PTHREADS
  5316. ** <li> SQLITE_MUTEX_W32
  5317. ** <li> SQLITE_MUTEX_NOOP
  5318. ** </ul>)^
  5319. **
  5320. ** ^The SQLITE_MUTEX_NOOP implementation is a set of routines
  5321. ** that does no real locking and is appropriate for use in
  5322. ** a single-threaded application. ^The SQLITE_MUTEX_OS2,
  5323. ** SQLITE_MUTEX_PTHREADS, and SQLITE_MUTEX_W32 implementations
  5324. ** are appropriate for use on OS/2, Unix, and Windows.
  5325. **
  5326. ** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
  5327. ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
  5328. ** implementation is included with the library. In this case the
  5329. ** application must supply a custom mutex implementation using the
  5330. ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
  5331. ** before calling sqlite3_initialize() or any other public sqlite3_
  5332. ** function that calls sqlite3_initialize().)^
  5333. **
  5334. ** ^The sqlite3_mutex_alloc() routine allocates a new
  5335. ** mutex and returns a pointer to it. ^If it returns NULL
  5336. ** that means that a mutex could not be allocated. ^SQLite
  5337. ** will unwind its stack and return an error. ^(The argument
  5338. ** to sqlite3_mutex_alloc() is one of these integer constants:
  5339. **
  5340. ** <ul>
  5341. ** <li> SQLITE_MUTEX_FAST
  5342. ** <li> SQLITE_MUTEX_RECURSIVE
  5343. ** <li> SQLITE_MUTEX_STATIC_MASTER
  5344. ** <li> SQLITE_MUTEX_STATIC_MEM
  5345. ** <li> SQLITE_MUTEX_STATIC_MEM2
  5346. ** <li> SQLITE_MUTEX_STATIC_PRNG
  5347. ** <li> SQLITE_MUTEX_STATIC_LRU
  5348. ** <li> SQLITE_MUTEX_STATIC_LRU2
  5349. ** </ul>)^
  5350. **
  5351. ** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
  5352. ** cause sqlite3_mutex_alloc() to create
  5353. ** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
  5354. ** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
  5355. ** The mutex implementation does not need to make a distinction
  5356. ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
  5357. ** not want to. ^SQLite will only request a recursive mutex in
  5358. ** cases where it really needs one. ^If a faster non-recursive mutex
  5359. ** implementation is available on the host platform, the mutex subsystem
  5360. ** might return such a mutex in response to SQLITE_MUTEX_FAST.
  5361. **
  5362. ** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
  5363. ** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
  5364. ** a pointer to a static preexisting mutex. ^Six static mutexes are
  5365. ** used by the current version of SQLite. Future versions of SQLite
  5366. ** may add additional static mutexes. Static mutexes are for internal
  5367. ** use by SQLite only. Applications that use SQLite mutexes should
  5368. ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
  5369. ** SQLITE_MUTEX_RECURSIVE.
  5370. **
  5371. ** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
  5372. ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
  5373. ** returns a different mutex on every call. ^But for the static
  5374. ** mutex types, the same mutex is returned on every call that has
  5375. ** the same type number.
  5376. **
  5377. ** ^The sqlite3_mutex_free() routine deallocates a previously
  5378. ** allocated dynamic mutex. ^SQLite is careful to deallocate every
  5379. ** dynamic mutex that it allocates. The dynamic mutexes must not be in
  5380. ** use when they are deallocated. Attempting to deallocate a static
  5381. ** mutex results in undefined behavior. ^SQLite never deallocates
  5382. ** a static mutex.
  5383. **
  5384. ** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
  5385. ** to enter a mutex. ^If another thread is already within the mutex,
  5386. ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
  5387. ** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
  5388. ** upon successful entry. ^(Mutexes created using
  5389. ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
  5390. ** In such cases the,
  5391. ** mutex must be exited an equal number of times before another thread
  5392. ** can enter.)^ ^(If the same thread tries to enter any other
  5393. ** kind of mutex more than once, the behavior is undefined.
  5394. ** SQLite will never exhibit
  5395. ** such behavior in its own use of mutexes.)^
  5396. **
  5397. ** ^(Some systems (for example, Windows 95) do not support the operation
  5398. ** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try()
  5399. ** will always return SQLITE_BUSY. The SQLite core only ever uses
  5400. ** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^
  5401. **
  5402. ** ^The sqlite3_mutex_leave() routine exits a mutex that was
  5403. ** previously entered by the same thread. ^(The behavior
  5404. ** is undefined if the mutex is not currently entered by the
  5405. ** calling thread or is not currently allocated. SQLite will
  5406. ** never do either.)^
  5407. **
  5408. ** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
  5409. ** sqlite3_mutex_leave() is a NULL pointer, then all three routines
  5410. ** behave as no-ops.
  5411. **
  5412. ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
  5413. */
  5414. SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int);
  5415. SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*);
  5416. SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*);
  5417. SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*);
  5418. SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*);
  5419. /*
  5420. ** CAPI3REF: Mutex Methods Object
  5421. **
  5422. ** An instance of this structure defines the low-level routines
  5423. ** used to allocate and use mutexes.
  5424. **
  5425. ** Usually, the default mutex implementations provided by SQLite are
  5426. ** sufficient, however the user has the option of substituting a custom
  5427. ** implementation for specialized deployments or systems for which SQLite
  5428. ** does not provide a suitable implementation. In this case, the user
  5429. ** creates and populates an instance of this structure to pass
  5430. ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
  5431. ** Additionally, an instance of this structure can be used as an
  5432. ** output variable when querying the system for the current mutex
  5433. ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
  5434. **
  5435. ** ^The xMutexInit method defined by this structure is invoked as
  5436. ** part of system initialization by the sqlite3_initialize() function.
  5437. ** ^The xMutexInit routine is called by SQLite exactly once for each
  5438. ** effective call to [sqlite3_initialize()].
  5439. **
  5440. ** ^The xMutexEnd method defined by this structure is invoked as
  5441. ** part of system shutdown by the sqlite3_shutdown() function. The
  5442. ** implementation of this method is expected to release all outstanding
  5443. ** resources obtained by the mutex methods implementation, especially
  5444. ** those obtained by the xMutexInit method. ^The xMutexEnd()
  5445. ** interface is invoked exactly once for each call to [sqlite3_shutdown()].
  5446. **
  5447. ** ^(The remaining seven methods defined by this structure (xMutexAlloc,
  5448. ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
  5449. ** xMutexNotheld) implement the following interfaces (respectively):
  5450. **
  5451. ** <ul>
  5452. ** <li> [sqlite3_mutex_alloc()] </li>
  5453. ** <li> [sqlite3_mutex_free()] </li>
  5454. ** <li> [sqlite3_mutex_enter()] </li>
  5455. ** <li> [sqlite3_mutex_try()] </li>
  5456. ** <li> [sqlite3_mutex_leave()] </li>
  5457. ** <li> [sqlite3_mutex_held()] </li>
  5458. ** <li> [sqlite3_mutex_notheld()] </li>
  5459. ** </ul>)^
  5460. **
  5461. ** The only difference is that the public sqlite3_XXX functions enumerated
  5462. ** above silently ignore any invocations that pass a NULL pointer instead
  5463. ** of a valid mutex handle. The implementations of the methods defined
  5464. ** by this structure are not required to handle this case, the results
  5465. ** of passing a NULL pointer instead of a valid mutex handle are undefined
  5466. ** (i.e. it is acceptable to provide an implementation that segfaults if
  5467. ** it is passed a NULL pointer).
  5468. **
  5469. ** The xMutexInit() method must be threadsafe. ^It must be harmless to
  5470. ** invoke xMutexInit() multiple times within the same process and without
  5471. ** intervening calls to xMutexEnd(). Second and subsequent calls to
  5472. ** xMutexInit() must be no-ops.
  5473. **
  5474. ** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
  5475. ** and its associates). ^Similarly, xMutexAlloc() must not use SQLite memory
  5476. ** allocation for a static mutex. ^However xMutexAlloc() may use SQLite
  5477. ** memory allocation for a fast or recursive mutex.
  5478. **
  5479. ** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
  5480. ** called, but only if the prior call to xMutexInit returned SQLITE_OK.
  5481. ** If xMutexInit fails in any way, it is expected to clean up after itself
  5482. ** prior to returning.
  5483. */
  5484. typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
  5485. struct sqlite3_mutex_methods {
  5486. int (*xMutexInit)(void);
  5487. int (*xMutexEnd)(void);
  5488. sqlite3_mutex *(*xMutexAlloc)(int);
  5489. void (*xMutexFree)(sqlite3_mutex *);
  5490. void (*xMutexEnter)(sqlite3_mutex *);
  5491. int (*xMutexTry)(sqlite3_mutex *);
  5492. void (*xMutexLeave)(sqlite3_mutex *);
  5493. int (*xMutexHeld)(sqlite3_mutex *);
  5494. int (*xMutexNotheld)(sqlite3_mutex *);
  5495. };
  5496. /*
  5497. ** CAPI3REF: Mutex Verification Routines
  5498. **
  5499. ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
  5500. ** are intended for use inside assert() statements. ^The SQLite core
  5501. ** never uses these routines except inside an assert() and applications
  5502. ** are advised to follow the lead of the core. ^The SQLite core only
  5503. ** provides implementations for these routines when it is compiled
  5504. ** with the SQLITE_DEBUG flag. ^External mutex implementations
  5505. ** are only required to provide these routines if SQLITE_DEBUG is
  5506. ** defined and if NDEBUG is not defined.
  5507. **
  5508. ** ^These routines should return true if the mutex in their argument
  5509. ** is held or not held, respectively, by the calling thread.
  5510. **
  5511. ** ^The implementation is not required to provide versions of these
  5512. ** routines that actually work. If the implementation does not provide working
  5513. ** versions of these routines, it should at least provide stubs that always
  5514. ** return true so that one does not get spurious assertion failures.
  5515. **
  5516. ** ^If the argument to sqlite3_mutex_held() is a NULL pointer then
  5517. ** the routine should return 1. This seems counter-intuitive since
  5518. ** clearly the mutex cannot be held if it does not exist. But
  5519. ** the reason the mutex does not exist is because the build is not
  5520. ** using mutexes. And we do not want the assert() containing the
  5521. ** call to sqlite3_mutex_held() to fail, so a non-zero return is
  5522. ** the appropriate thing to do. ^The sqlite3_mutex_notheld()
  5523. ** interface should also return 1 when given a NULL pointer.
  5524. */
  5525. #ifndef NDEBUG
  5526. SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*);
  5527. SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*);
  5528. #endif
  5529. /*
  5530. ** CAPI3REF: Mutex Types
  5531. **
  5532. ** The [sqlite3_mutex_alloc()] interface takes a single argument
  5533. ** which is one of these integer constants.
  5534. **
  5535. ** The set of static mutexes may change from one SQLite release to the
  5536. ** next. Applications that override the built-in mutex logic must be
  5537. ** prepared to accommodate additional static mutexes.
  5538. */
  5539. #define SQLITE_MUTEX_FAST 0
  5540. #define SQLITE_MUTEX_RECURSIVE 1
  5541. #define SQLITE_MUTEX_STATIC_MASTER 2
  5542. #define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */
  5543. #define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */
  5544. #define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */
  5545. #define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */
  5546. #define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */
  5547. #define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */
  5548. #define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */
  5549. /*
  5550. ** CAPI3REF: Retrieve the mutex for a database connection
  5551. **
  5552. ** ^This interface returns a pointer the [sqlite3_mutex] object that
  5553. ** serializes access to the [database connection] given in the argument
  5554. ** when the [threading mode] is Serialized.
  5555. ** ^If the [threading mode] is Single-thread or Multi-thread then this
  5556. ** routine returns a NULL pointer.
  5557. */
  5558. SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
  5559. /*
  5560. ** CAPI3REF: Low-Level Control Of Database Files
  5561. **
  5562. ** ^The [sqlite3_file_control()] interface makes a direct call to the
  5563. ** xFileControl method for the [sqlite3_io_methods] object associated
  5564. ** with a particular database identified by the second argument. ^The
  5565. ** name of the database is "main" for the main database or "temp" for the
  5566. ** TEMP database, or the name that appears after the AS keyword for
  5567. ** databases that are added using the [ATTACH] SQL command.
  5568. ** ^A NULL pointer can be used in place of "main" to refer to the
  5569. ** main database file.
  5570. ** ^The third and fourth parameters to this routine
  5571. ** are passed directly through to the second and third parameters of
  5572. ** the xFileControl method. ^The return value of the xFileControl
  5573. ** method becomes the return value of this routine.
  5574. **
  5575. ** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes
  5576. ** a pointer to the underlying [sqlite3_file] object to be written into
  5577. ** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER
  5578. ** case is a short-circuit path which does not actually invoke the
  5579. ** underlying sqlite3_io_methods.xFileControl method.
  5580. **
  5581. ** ^If the second parameter (zDbName) does not match the name of any
  5582. ** open database file, then SQLITE_ERROR is returned. ^This error
  5583. ** code is not remembered and will not be recalled by [sqlite3_errcode()]
  5584. ** or [sqlite3_errmsg()]. The underlying xFileControl method might
  5585. ** also return SQLITE_ERROR. There is no way to distinguish between
  5586. ** an incorrect zDbName and an SQLITE_ERROR return from the underlying
  5587. ** xFileControl method.
  5588. **
  5589. ** See also: [SQLITE_FCNTL_LOCKSTATE]
  5590. */
  5591. SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
  5592. /*
  5593. ** CAPI3REF: Testing Interface
  5594. **
  5595. ** ^The sqlite3_test_control() interface is used to read out internal
  5596. ** state of SQLite and to inject faults into SQLite for testing
  5597. ** purposes. ^The first parameter is an operation code that determines
  5598. ** the number, meaning, and operation of all subsequent parameters.
  5599. **
  5600. ** This interface is not for use by applications. It exists solely
  5601. ** for verifying the correct operation of the SQLite library. Depending
  5602. ** on how the SQLite library is compiled, this interface might not exist.
  5603. **
  5604. ** The details of the operation codes, their meanings, the parameters
  5605. ** they take, and what they do are all subject to change without notice.
  5606. ** Unlike most of the SQLite API, this function is not guaranteed to
  5607. ** operate consistently from one release to the next.
  5608. */
  5609. SQLITE_API int sqlite3_test_control(int op, ...);
  5610. /*
  5611. ** CAPI3REF: Testing Interface Operation Codes
  5612. **
  5613. ** These constants are the valid operation code parameters used
  5614. ** as the first argument to [sqlite3_test_control()].
  5615. **
  5616. ** These parameters and their meanings are subject to change
  5617. ** without notice. These values are for testing purposes only.
  5618. ** Applications should not use any of these parameters or the
  5619. ** [sqlite3_test_control()] interface.
  5620. */
  5621. #define SQLITE_TESTCTRL_FIRST 5
  5622. #define SQLITE_TESTCTRL_PRNG_SAVE 5
  5623. #define SQLITE_TESTCTRL_PRNG_RESTORE 6
  5624. #define SQLITE_TESTCTRL_PRNG_RESET 7
  5625. #define SQLITE_TESTCTRL_BITVEC_TEST 8
  5626. #define SQLITE_TESTCTRL_FAULT_INSTALL 9
  5627. #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10
  5628. #define SQLITE_TESTCTRL_PENDING_BYTE 11
  5629. #define SQLITE_TESTCTRL_ASSERT 12
  5630. #define SQLITE_TESTCTRL_ALWAYS 13
  5631. #define SQLITE_TESTCTRL_RESERVE 14
  5632. #define SQLITE_TESTCTRL_OPTIMIZATIONS 15
  5633. #define SQLITE_TESTCTRL_ISKEYWORD 16
  5634. #define SQLITE_TESTCTRL_SCRATCHMALLOC 17
  5635. #define SQLITE_TESTCTRL_LOCALTIME_FAULT 18
  5636. #define SQLITE_TESTCTRL_EXPLAIN_STMT 19
  5637. #define SQLITE_TESTCTRL_LAST 19
  5638. /*
  5639. ** CAPI3REF: SQLite Runtime Status
  5640. **
  5641. ** ^This interface is used to retrieve runtime status information
  5642. ** about the performance of SQLite, and optionally to reset various
  5643. ** highwater marks. ^The first argument is an integer code for
  5644. ** the specific parameter to measure. ^(Recognized integer codes
  5645. ** are of the form [status parameters | SQLITE_STATUS_...].)^
  5646. ** ^The current value of the parameter is returned into *pCurrent.
  5647. ** ^The highest recorded value is returned in *pHighwater. ^If the
  5648. ** resetFlag is true, then the highest record value is reset after
  5649. ** *pHighwater is written. ^(Some parameters do not record the highest
  5650. ** value. For those parameters
  5651. ** nothing is written into *pHighwater and the resetFlag is ignored.)^
  5652. ** ^(Other parameters record only the highwater mark and not the current
  5653. ** value. For these latter parameters nothing is written into *pCurrent.)^
  5654. **
  5655. ** ^The sqlite3_status() routine returns SQLITE_OK on success and a
  5656. ** non-zero [error code] on failure.
  5657. **
  5658. ** This routine is threadsafe but is not atomic. This routine can be
  5659. ** called while other threads are running the same or different SQLite
  5660. ** interfaces. However the values returned in *pCurrent and
  5661. ** *pHighwater reflect the status of SQLite at different points in time
  5662. ** and it is possible that another thread might change the parameter
  5663. ** in between the times when *pCurrent and *pHighwater are written.
  5664. **
  5665. ** See also: [sqlite3_db_status()]
  5666. */
  5667. SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
  5668. /*
  5669. ** CAPI3REF: Status Parameters
  5670. ** KEYWORDS: {status parameters}
  5671. **
  5672. ** These integer constants designate various run-time status parameters
  5673. ** that can be returned by [sqlite3_status()].
  5674. **
  5675. ** <dl>
  5676. ** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
  5677. ** <dd>This parameter is the current amount of memory checked out
  5678. ** using [sqlite3_malloc()], either directly or indirectly. The
  5679. ** figure includes calls made to [sqlite3_malloc()] by the application
  5680. ** and internal memory usage by the SQLite library. Scratch memory
  5681. ** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache
  5682. ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
  5683. ** this parameter. The amount returned is the sum of the allocation
  5684. ** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
  5685. **
  5686. ** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
  5687. ** <dd>This parameter records the largest memory allocation request
  5688. ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
  5689. ** internal equivalents). Only the value returned in the
  5690. ** *pHighwater parameter to [sqlite3_status()] is of interest.
  5691. ** The value written into the *pCurrent parameter is undefined.</dd>)^
  5692. **
  5693. ** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
  5694. ** <dd>This parameter records the number of separate memory allocations
  5695. ** currently checked out.</dd>)^
  5696. **
  5697. ** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
  5698. ** <dd>This parameter returns the number of pages used out of the
  5699. ** [pagecache memory allocator] that was configured using
  5700. ** [SQLITE_CONFIG_PAGECACHE]. The
  5701. ** value returned is in pages, not in bytes.</dd>)^
  5702. **
  5703. ** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]]
  5704. ** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
  5705. ** <dd>This parameter returns the number of bytes of page cache
  5706. ** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
  5707. ** buffer and where forced to overflow to [sqlite3_malloc()]. The
  5708. ** returned value includes allocations that overflowed because they
  5709. ** where too large (they were larger than the "sz" parameter to
  5710. ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
  5711. ** no space was left in the page cache.</dd>)^
  5712. **
  5713. ** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
  5714. ** <dd>This parameter records the largest memory allocation request
  5715. ** handed to [pagecache memory allocator]. Only the value returned in the
  5716. ** *pHighwater parameter to [sqlite3_status()] is of interest.
  5717. ** The value written into the *pCurrent parameter is undefined.</dd>)^
  5718. **
  5719. ** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt>
  5720. ** <dd>This parameter returns the number of allocations used out of the
  5721. ** [scratch memory allocator] configured using
  5722. ** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not
  5723. ** in bytes. Since a single thread may only have one scratch allocation
  5724. ** outstanding at time, this parameter also reports the number of threads
  5725. ** using scratch memory at the same time.</dd>)^
  5726. **
  5727. ** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
  5728. ** <dd>This parameter returns the number of bytes of scratch memory
  5729. ** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH]
  5730. ** buffer and where forced to overflow to [sqlite3_malloc()]. The values
  5731. ** returned include overflows because the requested allocation was too
  5732. ** larger (that is, because the requested allocation was larger than the
  5733. ** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer
  5734. ** slots were available.
  5735. ** </dd>)^
  5736. **
  5737. ** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
  5738. ** <dd>This parameter records the largest memory allocation request
  5739. ** handed to [scratch memory allocator]. Only the value returned in the
  5740. ** *pHighwater parameter to [sqlite3_status()] is of interest.
  5741. ** The value written into the *pCurrent parameter is undefined.</dd>)^
  5742. **
  5743. ** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
  5744. ** <dd>This parameter records the deepest parser stack. It is only
  5745. ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
  5746. ** </dl>
  5747. **
  5748. ** New status parameters may be added from time to time.
  5749. */
  5750. #define SQLITE_STATUS_MEMORY_USED 0
  5751. #define SQLITE_STATUS_PAGECACHE_USED 1
  5752. #define SQLITE_STATUS_PAGECACHE_OVERFLOW 2
  5753. #define SQLITE_STATUS_SCRATCH_USED 3
  5754. #define SQLITE_STATUS_SCRATCH_OVERFLOW 4
  5755. #define SQLITE_STATUS_MALLOC_SIZE 5
  5756. #define SQLITE_STATUS_PARSER_STACK 6
  5757. #define SQLITE_STATUS_PAGECACHE_SIZE 7
  5758. #define SQLITE_STATUS_SCRATCH_SIZE 8
  5759. #define SQLITE_STATUS_MALLOC_COUNT 9
  5760. /*
  5761. ** CAPI3REF: Database Connection Status
  5762. **
  5763. ** ^This interface is used to retrieve runtime status information
  5764. ** about a single [database connection]. ^The first argument is the
  5765. ** database connection object to be interrogated. ^The second argument
  5766. ** is an integer constant, taken from the set of
  5767. ** [SQLITE_DBSTATUS options], that
  5768. ** determines the parameter to interrogate. The set of
  5769. ** [SQLITE_DBSTATUS options] is likely
  5770. ** to grow in future releases of SQLite.
  5771. **
  5772. ** ^The current value of the requested parameter is written into *pCur
  5773. ** and the highest instantaneous value is written into *pHiwtr. ^If
  5774. ** the resetFlg is true, then the highest instantaneous value is
  5775. ** reset back down to the current value.
  5776. **
  5777. ** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
  5778. ** non-zero [error code] on failure.
  5779. **
  5780. ** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
  5781. */
  5782. SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
  5783. /*
  5784. ** CAPI3REF: Status Parameters for database connections
  5785. ** KEYWORDS: {SQLITE_DBSTATUS options}
  5786. **
  5787. ** These constants are the available integer "verbs" that can be passed as
  5788. ** the second argument to the [sqlite3_db_status()] interface.
  5789. **
  5790. ** New verbs may be added in future releases of SQLite. Existing verbs
  5791. ** might be discontinued. Applications should check the return code from
  5792. ** [sqlite3_db_status()] to make sure that the call worked.
  5793. ** The [sqlite3_db_status()] interface will return a non-zero error code
  5794. ** if a discontinued or unsupported verb is invoked.
  5795. **
  5796. ** <dl>
  5797. ** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
  5798. ** <dd>This parameter returns the number of lookaside memory slots currently
  5799. ** checked out.</dd>)^
  5800. **
  5801. ** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
  5802. ** <dd>This parameter returns the number malloc attempts that were
  5803. ** satisfied using lookaside memory. Only the high-water value is meaningful;
  5804. ** the current value is always zero.)^
  5805. **
  5806. ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]]
  5807. ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
  5808. ** <dd>This parameter returns the number malloc attempts that might have
  5809. ** been satisfied using lookaside memory but failed due to the amount of
  5810. ** memory requested being larger than the lookaside slot size.
  5811. ** Only the high-water value is meaningful;
  5812. ** the current value is always zero.)^
  5813. **
  5814. ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]]
  5815. ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
  5816. ** <dd>This parameter returns the number malloc attempts that might have
  5817. ** been satisfied using lookaside memory but failed due to all lookaside
  5818. ** memory already being in use.
  5819. ** Only the high-water value is meaningful;
  5820. ** the current value is always zero.)^
  5821. **
  5822. ** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
  5823. ** <dd>This parameter returns the approximate number of of bytes of heap
  5824. ** memory used by all pager caches associated with the database connection.)^
  5825. ** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
  5826. **
  5827. ** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
  5828. ** <dd>This parameter returns the approximate number of of bytes of heap
  5829. ** memory used to store the schema for all databases associated
  5830. ** with the connection - main, temp, and any [ATTACH]-ed databases.)^
  5831. ** ^The full amount of memory used by the schemas is reported, even if the
  5832. ** schema memory is shared with other database connections due to
  5833. ** [shared cache mode] being enabled.
  5834. ** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
  5835. **
  5836. ** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
  5837. ** <dd>This parameter returns the approximate number of of bytes of heap
  5838. ** and lookaside memory used by all prepared statements associated with
  5839. ** the database connection.)^
  5840. ** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
  5841. ** </dd>
  5842. **
  5843. ** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt>
  5844. ** <dd>This parameter returns the number of pager cache hits that have
  5845. ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT
  5846. ** is always 0.
  5847. ** </dd>
  5848. **
  5849. ** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt>
  5850. ** <dd>This parameter returns the number of pager cache misses that have
  5851. ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS
  5852. ** is always 0.
  5853. ** </dd>
  5854. ** </dl>
  5855. */
  5856. #define SQLITE_DBSTATUS_LOOKASIDE_USED 0
  5857. #define SQLITE_DBSTATUS_CACHE_USED 1
  5858. #define SQLITE_DBSTATUS_SCHEMA_USED 2
  5859. #define SQLITE_DBSTATUS_STMT_USED 3
  5860. #define SQLITE_DBSTATUS_LOOKASIDE_HIT 4
  5861. #define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5
  5862. #define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6
  5863. #define SQLITE_DBSTATUS_CACHE_HIT 7
  5864. #define SQLITE_DBSTATUS_CACHE_MISS 8
  5865. #define SQLITE_DBSTATUS_MAX 8 /* Largest defined DBSTATUS */
  5866. /*
  5867. ** CAPI3REF: Prepared Statement Status
  5868. **
  5869. ** ^(Each prepared statement maintains various
  5870. ** [SQLITE_STMTSTATUS counters] that measure the number
  5871. ** of times it has performed specific operations.)^ These counters can
  5872. ** be used to monitor the performance characteristics of the prepared
  5873. ** statements. For example, if the number of table steps greatly exceeds
  5874. ** the number of table searches or result rows, that would tend to indicate
  5875. ** that the prepared statement is using a full table scan rather than
  5876. ** an index.
  5877. **
  5878. ** ^(This interface is used to retrieve and reset counter values from
  5879. ** a [prepared statement]. The first argument is the prepared statement
  5880. ** object to be interrogated. The second argument
  5881. ** is an integer code for a specific [SQLITE_STMTSTATUS counter]
  5882. ** to be interrogated.)^
  5883. ** ^The current value of the requested counter is returned.
  5884. ** ^If the resetFlg is true, then the counter is reset to zero after this
  5885. ** interface call returns.
  5886. **
  5887. ** See also: [sqlite3_status()] and [sqlite3_db_status()].
  5888. */
  5889. SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
  5890. /*
  5891. ** CAPI3REF: Status Parameters for prepared statements
  5892. ** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters}
  5893. **
  5894. ** These preprocessor macros define integer codes that name counter
  5895. ** values associated with the [sqlite3_stmt_status()] interface.
  5896. ** The meanings of the various counters are as follows:
  5897. **
  5898. ** <dl>
  5899. ** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
  5900. ** <dd>^This is the number of times that SQLite has stepped forward in
  5901. ** a table as part of a full table scan. Large numbers for this counter
  5902. ** may indicate opportunities for performance improvement through
  5903. ** careful use of indices.</dd>
  5904. **
  5905. ** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt>
  5906. ** <dd>^This is the number of sort operations that have occurred.
  5907. ** A non-zero value in this counter may indicate an opportunity to
  5908. ** improvement performance through careful use of indices.</dd>
  5909. **
  5910. ** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
  5911. ** <dd>^This is the number of rows inserted into transient indices that
  5912. ** were created automatically in order to help joins run faster.
  5913. ** A non-zero value in this counter may indicate an opportunity to
  5914. ** improvement performance by adding permanent indices that do not
  5915. ** need to be reinitialized each time the statement is run.</dd>
  5916. ** </dl>
  5917. */
  5918. #define SQLITE_STMTSTATUS_FULLSCAN_STEP 1
  5919. #define SQLITE_STMTSTATUS_SORT 2
  5920. #define SQLITE_STMTSTATUS_AUTOINDEX 3
  5921. /*
  5922. ** CAPI3REF: Custom Page Cache Object
  5923. **
  5924. ** The sqlite3_pcache type is opaque. It is implemented by
  5925. ** the pluggable module. The SQLite core has no knowledge of
  5926. ** its size or internal structure and never deals with the
  5927. ** sqlite3_pcache object except by holding and passing pointers
  5928. ** to the object.
  5929. **
  5930. ** See [sqlite3_pcache_methods2] for additional information.
  5931. */
  5932. typedef struct sqlite3_pcache sqlite3_pcache;
  5933. /*
  5934. ** CAPI3REF: Custom Page Cache Object
  5935. **
  5936. ** The sqlite3_pcache_page object represents a single page in the
  5937. ** page cache. The page cache will allocate instances of this
  5938. ** object. Various methods of the page cache use pointers to instances
  5939. ** of this object as parameters or as their return value.
  5940. **
  5941. ** See [sqlite3_pcache_methods2] for additional information.
  5942. */
  5943. typedef struct sqlite3_pcache_page sqlite3_pcache_page;
  5944. struct sqlite3_pcache_page {
  5945. void *pBuf; /* The content of the page */
  5946. void *pExtra; /* Extra information associated with the page */
  5947. };
  5948. /*
  5949. ** CAPI3REF: Application Defined Page Cache.
  5950. ** KEYWORDS: {page cache}
  5951. **
  5952. ** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can
  5953. ** register an alternative page cache implementation by passing in an
  5954. ** instance of the sqlite3_pcache_methods2 structure.)^
  5955. ** In many applications, most of the heap memory allocated by
  5956. ** SQLite is used for the page cache.
  5957. ** By implementing a
  5958. ** custom page cache using this API, an application can better control
  5959. ** the amount of memory consumed by SQLite, the way in which
  5960. ** that memory is allocated and released, and the policies used to
  5961. ** determine exactly which parts of a database file are cached and for
  5962. ** how long.
  5963. **
  5964. ** The alternative page cache mechanism is an
  5965. ** extreme measure that is only needed by the most demanding applications.
  5966. ** The built-in page cache is recommended for most uses.
  5967. **
  5968. ** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an
  5969. ** internal buffer by SQLite within the call to [sqlite3_config]. Hence
  5970. ** the application may discard the parameter after the call to
  5971. ** [sqlite3_config()] returns.)^
  5972. **
  5973. ** [[the xInit() page cache method]]
  5974. ** ^(The xInit() method is called once for each effective
  5975. ** call to [sqlite3_initialize()])^
  5976. ** (usually only once during the lifetime of the process). ^(The xInit()
  5977. ** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^
  5978. ** The intent of the xInit() method is to set up global data structures
  5979. ** required by the custom page cache implementation.
  5980. ** ^(If the xInit() method is NULL, then the
  5981. ** built-in default page cache is used instead of the application defined
  5982. ** page cache.)^
  5983. **
  5984. ** [[the xShutdown() page cache method]]
  5985. ** ^The xShutdown() method is called by [sqlite3_shutdown()].
  5986. ** It can be used to clean up
  5987. ** any outstanding resources before process shutdown, if required.
  5988. ** ^The xShutdown() method may be NULL.
  5989. **
  5990. ** ^SQLite automatically serializes calls to the xInit method,
  5991. ** so the xInit method need not be threadsafe. ^The
  5992. ** xShutdown method is only called from [sqlite3_shutdown()] so it does
  5993. ** not need to be threadsafe either. All other methods must be threadsafe
  5994. ** in multithreaded applications.
  5995. **
  5996. ** ^SQLite will never invoke xInit() more than once without an intervening
  5997. ** call to xShutdown().
  5998. **
  5999. ** [[the xCreate() page cache methods]]
  6000. ** ^SQLite invokes the xCreate() method to construct a new cache instance.
  6001. ** SQLite will typically create one cache instance for each open database file,
  6002. ** though this is not guaranteed. ^The
  6003. ** first parameter, szPage, is the size in bytes of the pages that must
  6004. ** be allocated by the cache. ^szPage will always a power of two. ^The
  6005. ** second parameter szExtra is a number of bytes of extra storage
  6006. ** associated with each page cache entry. ^The szExtra parameter will
  6007. ** a number less than 250. SQLite will use the
  6008. ** extra szExtra bytes on each page to store metadata about the underlying
  6009. ** database page on disk. The value passed into szExtra depends
  6010. ** on the SQLite version, the target platform, and how SQLite was compiled.
  6011. ** ^The third argument to xCreate(), bPurgeable, is true if the cache being
  6012. ** created will be used to cache database pages of a file stored on disk, or
  6013. ** false if it is used for an in-memory database. The cache implementation
  6014. ** does not have to do anything special based with the value of bPurgeable;
  6015. ** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will
  6016. ** never invoke xUnpin() except to deliberately delete a page.
  6017. ** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
  6018. ** false will always have the "discard" flag set to true.
  6019. ** ^Hence, a cache created with bPurgeable false will
  6020. ** never contain any unpinned pages.
  6021. **
  6022. ** [[the xCachesize() page cache method]]
  6023. ** ^(The xCachesize() method may be called at any time by SQLite to set the
  6024. ** suggested maximum cache-size (number of pages stored by) the cache
  6025. ** instance passed as the first argument. This is the value configured using
  6026. ** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable
  6027. ** parameter, the implementation is not required to do anything with this
  6028. ** value; it is advisory only.
  6029. **
  6030. ** [[the xPagecount() page cache methods]]
  6031. ** The xPagecount() method must return the number of pages currently
  6032. ** stored in the cache, both pinned and unpinned.
  6033. **
  6034. ** [[the xFetch() page cache methods]]
  6035. ** The xFetch() method locates a page in the cache and returns a pointer to
  6036. ** an sqlite3_pcache_page object associated with that page, or a NULL pointer.
  6037. ** The pBuf element of the returned sqlite3_pcache_page object will be a
  6038. ** pointer to a buffer of szPage bytes used to store the content of a
  6039. ** single database page. The pExtra element of sqlite3_pcache_page will be
  6040. ** a pointer to the szExtra bytes of extra storage that SQLite has requested
  6041. ** for each entry in the page cache.
  6042. **
  6043. ** The page to be fetched is determined by the key. ^The minimum key value
  6044. ** is 1. After it has been retrieved using xFetch, the page is considered
  6045. ** to be "pinned".
  6046. **
  6047. ** If the requested page is already in the page cache, then the page cache
  6048. ** implementation must return a pointer to the page buffer with its content
  6049. ** intact. If the requested page is not already in the cache, then the
  6050. ** cache implementation should use the value of the createFlag
  6051. ** parameter to help it determined what action to take:
  6052. **
  6053. ** <table border=1 width=85% align=center>
  6054. ** <tr><th> createFlag <th> Behaviour when page is not already in cache
  6055. ** <tr><td> 0 <td> Do not allocate a new page. Return NULL.
  6056. ** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
  6057. ** Otherwise return NULL.
  6058. ** <tr><td> 2 <td> Make every effort to allocate a new page. Only return
  6059. ** NULL if allocating a new page is effectively impossible.
  6060. ** </table>
  6061. **
  6062. ** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite
  6063. ** will only use a createFlag of 2 after a prior call with a createFlag of 1
  6064. ** failed.)^ In between the to xFetch() calls, SQLite may
  6065. ** attempt to unpin one or more cache pages by spilling the content of
  6066. ** pinned pages to disk and synching the operating system disk cache.
  6067. **
  6068. ** [[the xUnpin() page cache method]]
  6069. ** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
  6070. ** as its second argument. If the third parameter, discard, is non-zero,
  6071. ** then the page must be evicted from the cache.
  6072. ** ^If the discard parameter is
  6073. ** zero, then the page may be discarded or retained at the discretion of
  6074. ** page cache implementation. ^The page cache implementation
  6075. ** may choose to evict unpinned pages at any time.
  6076. **
  6077. ** The cache must not perform any reference counting. A single
  6078. ** call to xUnpin() unpins the page regardless of the number of prior calls
  6079. ** to xFetch().
  6080. **
  6081. ** [[the xRekey() page cache methods]]
  6082. ** The xRekey() method is used to change the key value associated with the
  6083. ** page passed as the second argument. If the cache
  6084. ** previously contains an entry associated with newKey, it must be
  6085. ** discarded. ^Any prior cache entry associated with newKey is guaranteed not
  6086. ** to be pinned.
  6087. **
  6088. ** When SQLite calls the xTruncate() method, the cache must discard all
  6089. ** existing cache entries with page numbers (keys) greater than or equal
  6090. ** to the value of the iLimit parameter passed to xTruncate(). If any
  6091. ** of these pages are pinned, they are implicitly unpinned, meaning that
  6092. ** they can be safely discarded.
  6093. **
  6094. ** [[the xDestroy() page cache method]]
  6095. ** ^The xDestroy() method is used to delete a cache allocated by xCreate().
  6096. ** All resources associated with the specified cache should be freed. ^After
  6097. ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
  6098. ** handle invalid, and will not use it with any other sqlite3_pcache_methods2
  6099. ** functions.
  6100. **
  6101. ** [[the xShrink() page cache method]]
  6102. ** ^SQLite invokes the xShrink() method when it wants the page cache to
  6103. ** free up as much of heap memory as possible. The page cache implementation
  6104. ** is not obligated to free any memory, but well-behaved implementations should
  6105. ** do their best.
  6106. */
  6107. typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
  6108. struct sqlite3_pcache_methods2 {
  6109. int iVersion;
  6110. void *pArg;
  6111. int (*xInit)(void*);
  6112. void (*xShutdown)(void*);
  6113. sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
  6114. void (*xCachesize)(sqlite3_pcache*, int nCachesize);
  6115. int (*xPagecount)(sqlite3_pcache*);
  6116. sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
  6117. void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
  6118. void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*,
  6119. unsigned oldKey, unsigned newKey);
  6120. void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
  6121. void (*xDestroy)(sqlite3_pcache*);
  6122. void (*xShrink)(sqlite3_pcache*);
  6123. };
  6124. /*
  6125. ** This is the obsolete pcache_methods object that has now been replaced
  6126. ** by sqlite3_pcache_methods2. This object is not used by SQLite. It is
  6127. ** retained in the header file for backwards compatibility only.
  6128. */
  6129. typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
  6130. struct sqlite3_pcache_methods {
  6131. void *pArg;
  6132. int (*xInit)(void*);
  6133. void (*xShutdown)(void*);
  6134. sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
  6135. void (*xCachesize)(sqlite3_pcache*, int nCachesize);
  6136. int (*xPagecount)(sqlite3_pcache*);
  6137. void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
  6138. void (*xUnpin)(sqlite3_pcache*, void*, int discard);
  6139. void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
  6140. void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
  6141. void (*xDestroy)(sqlite3_pcache*);
  6142. };
  6143. /*
  6144. ** CAPI3REF: Online Backup Object
  6145. **
  6146. ** The sqlite3_backup object records state information about an ongoing
  6147. ** online backup operation. ^The sqlite3_backup object is created by
  6148. ** a call to [sqlite3_backup_init()] and is destroyed by a call to
  6149. ** [sqlite3_backup_finish()].
  6150. **
  6151. ** See Also: [Using the SQLite Online Backup API]
  6152. */
  6153. typedef struct sqlite3_backup sqlite3_backup;
  6154. /*
  6155. ** CAPI3REF: Online Backup API.
  6156. **
  6157. ** The backup API copies the content of one database into another.
  6158. ** It is useful either for creating backups of databases or
  6159. ** for copying in-memory databases to or from persistent files.
  6160. **
  6161. ** See Also: [Using the SQLite Online Backup API]
  6162. **
  6163. ** ^SQLite holds a write transaction open on the destination database file
  6164. ** for the duration of the backup operation.
  6165. ** ^The source database is read-locked only while it is being read;
  6166. ** it is not locked continuously for the entire backup operation.
  6167. ** ^Thus, the backup may be performed on a live source database without
  6168. ** preventing other database connections from
  6169. ** reading or writing to the source database while the backup is underway.
  6170. **
  6171. ** ^(To perform a backup operation:
  6172. ** <ol>
  6173. ** <li><b>sqlite3_backup_init()</b> is called once to initialize the
  6174. ** backup,
  6175. ** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
  6176. ** the data between the two databases, and finally
  6177. ** <li><b>sqlite3_backup_finish()</b> is called to release all resources
  6178. ** associated with the backup operation.
  6179. ** </ol>)^
  6180. ** There should be exactly one call to sqlite3_backup_finish() for each
  6181. ** successful call to sqlite3_backup_init().
  6182. **
  6183. ** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
  6184. **
  6185. ** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
  6186. ** [database connection] associated with the destination database
  6187. ** and the database name, respectively.
  6188. ** ^The database name is "main" for the main database, "temp" for the
  6189. ** temporary database, or the name specified after the AS keyword in
  6190. ** an [ATTACH] statement for an attached database.
  6191. ** ^The S and M arguments passed to
  6192. ** sqlite3_backup_init(D,N,S,M) identify the [database connection]
  6193. ** and database name of the source database, respectively.
  6194. ** ^The source and destination [database connections] (parameters S and D)
  6195. ** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
  6196. ** an error.
  6197. **
  6198. ** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
  6199. ** returned and an error code and error message are stored in the
  6200. ** destination [database connection] D.
  6201. ** ^The error code and message for the failed call to sqlite3_backup_init()
  6202. ** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
  6203. ** [sqlite3_errmsg16()] functions.
  6204. ** ^A successful call to sqlite3_backup_init() returns a pointer to an
  6205. ** [sqlite3_backup] object.
  6206. ** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
  6207. ** sqlite3_backup_finish() functions to perform the specified backup
  6208. ** operation.
  6209. **
  6210. ** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
  6211. **
  6212. ** ^Function sqlite3_backup_step(B,N) will copy up to N pages between
  6213. ** the source and destination databases specified by [sqlite3_backup] object B.
  6214. ** ^If N is negative, all remaining source pages are copied.
  6215. ** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
  6216. ** are still more pages to be copied, then the function returns [SQLITE_OK].
  6217. ** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
  6218. ** from source to destination, then it returns [SQLITE_DONE].
  6219. ** ^If an error occurs while running sqlite3_backup_step(B,N),
  6220. ** then an [error code] is returned. ^As well as [SQLITE_OK] and
  6221. ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
  6222. ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
  6223. ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
  6224. **
  6225. ** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
  6226. ** <ol>
  6227. ** <li> the destination database was opened read-only, or
  6228. ** <li> the destination database is using write-ahead-log journaling
  6229. ** and the destination and source page sizes differ, or
  6230. ** <li> the destination database is an in-memory database and the
  6231. ** destination and source page sizes differ.
  6232. ** </ol>)^
  6233. **
  6234. ** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
  6235. ** the [sqlite3_busy_handler | busy-handler function]
  6236. ** is invoked (if one is specified). ^If the
  6237. ** busy-handler returns non-zero before the lock is available, then
  6238. ** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
  6239. ** sqlite3_backup_step() can be retried later. ^If the source
  6240. ** [database connection]
  6241. ** is being used to write to the source database when sqlite3_backup_step()
  6242. ** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
  6243. ** case the call to sqlite3_backup_step() can be retried later on. ^(If
  6244. ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
  6245. ** [SQLITE_READONLY] is returned, then
  6246. ** there is no point in retrying the call to sqlite3_backup_step(). These
  6247. ** errors are considered fatal.)^ The application must accept
  6248. ** that the backup operation has failed and pass the backup operation handle
  6249. ** to the sqlite3_backup_finish() to release associated resources.
  6250. **
  6251. ** ^The first call to sqlite3_backup_step() obtains an exclusive lock
  6252. ** on the destination file. ^The exclusive lock is not released until either
  6253. ** sqlite3_backup_finish() is called or the backup operation is complete
  6254. ** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to
  6255. ** sqlite3_backup_step() obtains a [shared lock] on the source database that
  6256. ** lasts for the duration of the sqlite3_backup_step() call.
  6257. ** ^Because the source database is not locked between calls to
  6258. ** sqlite3_backup_step(), the source database may be modified mid-way
  6259. ** through the backup process. ^If the source database is modified by an
  6260. ** external process or via a database connection other than the one being
  6261. ** used by the backup operation, then the backup will be automatically
  6262. ** restarted by the next call to sqlite3_backup_step(). ^If the source
  6263. ** database is modified by the using the same database connection as is used
  6264. ** by the backup operation, then the backup database is automatically
  6265. ** updated at the same time.
  6266. **
  6267. ** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
  6268. **
  6269. ** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the
  6270. ** application wishes to abandon the backup operation, the application
  6271. ** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
  6272. ** ^The sqlite3_backup_finish() interfaces releases all
  6273. ** resources associated with the [sqlite3_backup] object.
  6274. ** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
  6275. ** active write-transaction on the destination database is rolled back.
  6276. ** The [sqlite3_backup] object is invalid
  6277. ** and may not be used following a call to sqlite3_backup_finish().
  6278. **
  6279. ** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
  6280. ** sqlite3_backup_step() errors occurred, regardless or whether or not
  6281. ** sqlite3_backup_step() completed.
  6282. ** ^If an out-of-memory condition or IO error occurred during any prior
  6283. ** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
  6284. ** sqlite3_backup_finish() returns the corresponding [error code].
  6285. **
  6286. ** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
  6287. ** is not a permanent error and does not affect the return value of
  6288. ** sqlite3_backup_finish().
  6289. **
  6290. ** [[sqlite3_backup__remaining()]] [[sqlite3_backup_pagecount()]]
  6291. ** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
  6292. **
  6293. ** ^Each call to sqlite3_backup_step() sets two values inside
  6294. ** the [sqlite3_backup] object: the number of pages still to be backed
  6295. ** up and the total number of pages in the source database file.
  6296. ** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces
  6297. ** retrieve these two values, respectively.
  6298. **
  6299. ** ^The values returned by these functions are only updated by
  6300. ** sqlite3_backup_step(). ^If the source database is modified during a backup
  6301. ** operation, then the values are not updated to account for any extra
  6302. ** pages that need to be updated or the size of the source database file
  6303. ** changing.
  6304. **
  6305. ** <b>Concurrent Usage of Database Handles</b>
  6306. **
  6307. ** ^The source [database connection] may be used by the application for other
  6308. ** purposes while a backup operation is underway or being initialized.
  6309. ** ^If SQLite is compiled and configured to support threadsafe database
  6310. ** connections, then the source database connection may be used concurrently
  6311. ** from within other threads.
  6312. **
  6313. ** However, the application must guarantee that the destination
  6314. ** [database connection] is not passed to any other API (by any thread) after
  6315. ** sqlite3_backup_init() is called and before the corresponding call to
  6316. ** sqlite3_backup_finish(). SQLite does not currently check to see
  6317. ** if the application incorrectly accesses the destination [database connection]
  6318. ** and so no error code is reported, but the operations may malfunction
  6319. ** nevertheless. Use of the destination database connection while a
  6320. ** backup is in progress might also also cause a mutex deadlock.
  6321. **
  6322. ** If running in [shared cache mode], the application must
  6323. ** guarantee that the shared cache used by the destination database
  6324. ** is not accessed while the backup is running. In practice this means
  6325. ** that the application must guarantee that the disk file being
  6326. ** backed up to is not accessed by any connection within the process,
  6327. ** not just the specific connection that was passed to sqlite3_backup_init().
  6328. **
  6329. ** The [sqlite3_backup] object itself is partially threadsafe. Multiple
  6330. ** threads may safely make multiple concurrent calls to sqlite3_backup_step().
  6331. ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
  6332. ** APIs are not strictly speaking threadsafe. If they are invoked at the
  6333. ** same time as another thread is invoking sqlite3_backup_step() it is
  6334. ** possible that they return invalid values.
  6335. */
  6336. SQLITE_API sqlite3_backup *sqlite3_backup_init(
  6337. sqlite3 *pDest, /* Destination database handle */
  6338. const char *zDestName, /* Destination database name */
  6339. sqlite3 *pSource, /* Source database handle */
  6340. const char *zSourceName /* Source database name */
  6341. );
  6342. SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage);
  6343. SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p);
  6344. SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p);
  6345. SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p);
  6346. /*
  6347. ** CAPI3REF: Unlock Notification
  6348. **
  6349. ** ^When running in shared-cache mode, a database operation may fail with
  6350. ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
  6351. ** individual tables within the shared-cache cannot be obtained. See
  6352. ** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
  6353. ** ^This API may be used to register a callback that SQLite will invoke
  6354. ** when the connection currently holding the required lock relinquishes it.
  6355. ** ^This API is only available if the library was compiled with the
  6356. ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
  6357. **
  6358. ** See Also: [Using the SQLite Unlock Notification Feature].
  6359. **
  6360. ** ^Shared-cache locks are released when a database connection concludes
  6361. ** its current transaction, either by committing it or rolling it back.
  6362. **
  6363. ** ^When a connection (known as the blocked connection) fails to obtain a
  6364. ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
  6365. ** identity of the database connection (the blocking connection) that
  6366. ** has locked the required resource is stored internally. ^After an
  6367. ** application receives an SQLITE_LOCKED error, it may call the
  6368. ** sqlite3_unlock_notify() method with the blocked connection handle as
  6369. ** the first argument to register for a callback that will be invoked
  6370. ** when the blocking connections current transaction is concluded. ^The
  6371. ** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
  6372. ** call that concludes the blocking connections transaction.
  6373. **
  6374. ** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
  6375. ** there is a chance that the blocking connection will have already
  6376. ** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
  6377. ** If this happens, then the specified callback is invoked immediately,
  6378. ** from within the call to sqlite3_unlock_notify().)^
  6379. **
  6380. ** ^If the blocked connection is attempting to obtain a write-lock on a
  6381. ** shared-cache table, and more than one other connection currently holds
  6382. ** a read-lock on the same table, then SQLite arbitrarily selects one of
  6383. ** the other connections to use as the blocking connection.
  6384. **
  6385. ** ^(There may be at most one unlock-notify callback registered by a
  6386. ** blocked connection. If sqlite3_unlock_notify() is called when the
  6387. ** blocked connection already has a registered unlock-notify callback,
  6388. ** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
  6389. ** called with a NULL pointer as its second argument, then any existing
  6390. ** unlock-notify callback is canceled. ^The blocked connections
  6391. ** unlock-notify callback may also be canceled by closing the blocked
  6392. ** connection using [sqlite3_close()].
  6393. **
  6394. ** The unlock-notify callback is not reentrant. If an application invokes
  6395. ** any sqlite3_xxx API functions from within an unlock-notify callback, a
  6396. ** crash or deadlock may be the result.
  6397. **
  6398. ** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
  6399. ** returns SQLITE_OK.
  6400. **
  6401. ** <b>Callback Invocation Details</b>
  6402. **
  6403. ** When an unlock-notify callback is registered, the application provides a
  6404. ** single void* pointer that is passed to the callback when it is invoked.
  6405. ** However, the signature of the callback function allows SQLite to pass
  6406. ** it an array of void* context pointers. The first argument passed to
  6407. ** an unlock-notify callback is a pointer to an array of void* pointers,
  6408. ** and the second is the number of entries in the array.
  6409. **
  6410. ** When a blocking connections transaction is concluded, there may be
  6411. ** more than one blocked connection that has registered for an unlock-notify
  6412. ** callback. ^If two or more such blocked connections have specified the
  6413. ** same callback function, then instead of invoking the callback function
  6414. ** multiple times, it is invoked once with the set of void* context pointers
  6415. ** specified by the blocked connections bundled together into an array.
  6416. ** This gives the application an opportunity to prioritize any actions
  6417. ** related to the set of unblocked database connections.
  6418. **
  6419. ** <b>Deadlock Detection</b>
  6420. **
  6421. ** Assuming that after registering for an unlock-notify callback a
  6422. ** database waits for the callback to be issued before taking any further
  6423. ** action (a reasonable assumption), then using this API may cause the
  6424. ** application to deadlock. For example, if connection X is waiting for
  6425. ** connection Y's transaction to be concluded, and similarly connection
  6426. ** Y is waiting on connection X's transaction, then neither connection
  6427. ** will proceed and the system may remain deadlocked indefinitely.
  6428. **
  6429. ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
  6430. ** detection. ^If a given call to sqlite3_unlock_notify() would put the
  6431. ** system in a deadlocked state, then SQLITE_LOCKED is returned and no
  6432. ** unlock-notify callback is registered. The system is said to be in
  6433. ** a deadlocked state if connection A has registered for an unlock-notify
  6434. ** callback on the conclusion of connection B's transaction, and connection
  6435. ** B has itself registered for an unlock-notify callback when connection
  6436. ** A's transaction is concluded. ^Indirect deadlock is also detected, so
  6437. ** the system is also considered to be deadlocked if connection B has
  6438. ** registered for an unlock-notify callback on the conclusion of connection
  6439. ** C's transaction, where connection C is waiting on connection A. ^Any
  6440. ** number of levels of indirection are allowed.
  6441. **
  6442. ** <b>The "DROP TABLE" Exception</b>
  6443. **
  6444. ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost
  6445. ** always appropriate to call sqlite3_unlock_notify(). There is however,
  6446. ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
  6447. ** SQLite checks if there are any currently executing SELECT statements
  6448. ** that belong to the same connection. If there are, SQLITE_LOCKED is
  6449. ** returned. In this case there is no "blocking connection", so invoking
  6450. ** sqlite3_unlock_notify() results in the unlock-notify callback being
  6451. ** invoked immediately. If the application then re-attempts the "DROP TABLE"
  6452. ** or "DROP INDEX" query, an infinite loop might be the result.
  6453. **
  6454. ** One way around this problem is to check the extended error code returned
  6455. ** by an sqlite3_step() call. ^(If there is a blocking connection, then the
  6456. ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
  6457. ** the special "DROP TABLE/INDEX" case, the extended error code is just
  6458. ** SQLITE_LOCKED.)^
  6459. */
  6460. SQLITE_API int sqlite3_unlock_notify(
  6461. sqlite3 *pBlocked, /* Waiting connection */
  6462. void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */
  6463. void *pNotifyArg /* Argument to pass to xNotify */
  6464. );
  6465. /*
  6466. ** CAPI3REF: String Comparison
  6467. **
  6468. ** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications
  6469. ** and extensions to compare the contents of two buffers containing UTF-8
  6470. ** strings in a case-independent fashion, using the same definition of "case
  6471. ** independence" that SQLite uses internally when comparing identifiers.
  6472. */
  6473. SQLITE_API int sqlite3_stricmp(const char *, const char *);
  6474. SQLITE_API int sqlite3_strnicmp(const char *, const char *, int);
  6475. /*
  6476. ** CAPI3REF: Error Logging Interface
  6477. **
  6478. ** ^The [sqlite3_log()] interface writes a message into the error log
  6479. ** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
  6480. ** ^If logging is enabled, the zFormat string and subsequent arguments are
  6481. ** used with [sqlite3_snprintf()] to generate the final output string.
  6482. **
  6483. ** The sqlite3_log() interface is intended for use by extensions such as
  6484. ** virtual tables, collating functions, and SQL functions. While there is
  6485. ** nothing to prevent an application from calling sqlite3_log(), doing so
  6486. ** is considered bad form.
  6487. **
  6488. ** The zFormat string must not be NULL.
  6489. **
  6490. ** To avoid deadlocks and other threading problems, the sqlite3_log() routine
  6491. ** will not use dynamically allocated memory. The log message is stored in
  6492. ** a fixed-length buffer on the stack. If the log message is longer than
  6493. ** a few hundred characters, it will be truncated to the length of the
  6494. ** buffer.
  6495. */
  6496. SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...);
  6497. /*
  6498. ** CAPI3REF: Write-Ahead Log Commit Hook
  6499. **
  6500. ** ^The [sqlite3_wal_hook()] function is used to register a callback that
  6501. ** will be invoked each time a database connection commits data to a
  6502. ** [write-ahead log] (i.e. whenever a transaction is committed in
  6503. ** [journal_mode | journal_mode=WAL mode]).
  6504. **
  6505. ** ^The callback is invoked by SQLite after the commit has taken place and
  6506. ** the associated write-lock on the database released, so the implementation
  6507. ** may read, write or [checkpoint] the database as required.
  6508. **
  6509. ** ^The first parameter passed to the callback function when it is invoked
  6510. ** is a copy of the third parameter passed to sqlite3_wal_hook() when
  6511. ** registering the callback. ^The second is a copy of the database handle.
  6512. ** ^The third parameter is the name of the database that was written to -
  6513. ** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
  6514. ** is the number of pages currently in the write-ahead log file,
  6515. ** including those that were just committed.
  6516. **
  6517. ** The callback function should normally return [SQLITE_OK]. ^If an error
  6518. ** code is returned, that error will propagate back up through the
  6519. ** SQLite code base to cause the statement that provoked the callback
  6520. ** to report an error, though the commit will have still occurred. If the
  6521. ** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
  6522. ** that does not correspond to any valid SQLite error code, the results
  6523. ** are undefined.
  6524. **
  6525. ** A single database handle may have at most a single write-ahead log callback
  6526. ** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
  6527. ** previously registered write-ahead log callback. ^Note that the
  6528. ** [sqlite3_wal_autocheckpoint()] interface and the
  6529. ** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
  6530. ** those overwrite any prior [sqlite3_wal_hook()] settings.
  6531. */
  6532. SQLITE_API void *sqlite3_wal_hook(
  6533. sqlite3*,
  6534. int(*)(void *,sqlite3*,const char*,int),
  6535. void*
  6536. );
  6537. /*
  6538. ** CAPI3REF: Configure an auto-checkpoint
  6539. **
  6540. ** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
  6541. ** [sqlite3_wal_hook()] that causes any database on [database connection] D
  6542. ** to automatically [checkpoint]
  6543. ** after committing a transaction if there are N or
  6544. ** more frames in the [write-ahead log] file. ^Passing zero or
  6545. ** a negative value as the nFrame parameter disables automatic
  6546. ** checkpoints entirely.
  6547. **
  6548. ** ^The callback registered by this function replaces any existing callback
  6549. ** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback
  6550. ** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
  6551. ** configured by this function.
  6552. **
  6553. ** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
  6554. ** from SQL.
  6555. **
  6556. ** ^Every new [database connection] defaults to having the auto-checkpoint
  6557. ** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
  6558. ** pages. The use of this interface
  6559. ** is only necessary if the default setting is found to be suboptimal
  6560. ** for a particular application.
  6561. */
  6562. SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
  6563. /*
  6564. ** CAPI3REF: Checkpoint a database
  6565. **
  6566. ** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X
  6567. ** on [database connection] D to be [checkpointed]. ^If X is NULL or an
  6568. ** empty string, then a checkpoint is run on all databases of
  6569. ** connection D. ^If the database connection D is not in
  6570. ** [WAL | write-ahead log mode] then this interface is a harmless no-op.
  6571. **
  6572. ** ^The [wal_checkpoint pragma] can be used to invoke this interface
  6573. ** from SQL. ^The [sqlite3_wal_autocheckpoint()] interface and the
  6574. ** [wal_autocheckpoint pragma] can be used to cause this interface to be
  6575. ** run whenever the WAL reaches a certain size threshold.
  6576. **
  6577. ** See also: [sqlite3_wal_checkpoint_v2()]
  6578. */
  6579. SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
  6580. /*
  6581. ** CAPI3REF: Checkpoint a database
  6582. **
  6583. ** Run a checkpoint operation on WAL database zDb attached to database
  6584. ** handle db. The specific operation is determined by the value of the
  6585. ** eMode parameter:
  6586. **
  6587. ** <dl>
  6588. ** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
  6589. ** Checkpoint as many frames as possible without waiting for any database
  6590. ** readers or writers to finish. Sync the db file if all frames in the log
  6591. ** are checkpointed. This mode is the same as calling
  6592. ** sqlite3_wal_checkpoint(). The busy-handler callback is never invoked.
  6593. **
  6594. ** <dt>SQLITE_CHECKPOINT_FULL<dd>
  6595. ** This mode blocks (calls the busy-handler callback) until there is no
  6596. ** database writer and all readers are reading from the most recent database
  6597. ** snapshot. It then checkpoints all frames in the log file and syncs the
  6598. ** database file. This call blocks database writers while it is running,
  6599. ** but not database readers.
  6600. **
  6601. ** <dt>SQLITE_CHECKPOINT_RESTART<dd>
  6602. ** This mode works the same way as SQLITE_CHECKPOINT_FULL, except after
  6603. ** checkpointing the log file it blocks (calls the busy-handler callback)
  6604. ** until all readers are reading from the database file only. This ensures
  6605. ** that the next client to write to the database file restarts the log file
  6606. ** from the beginning. This call blocks database writers while it is running,
  6607. ** but not database readers.
  6608. ** </dl>
  6609. **
  6610. ** If pnLog is not NULL, then *pnLog is set to the total number of frames in
  6611. ** the log file before returning. If pnCkpt is not NULL, then *pnCkpt is set to
  6612. ** the total number of checkpointed frames (including any that were already
  6613. ** checkpointed when this function is called). *pnLog and *pnCkpt may be
  6614. ** populated even if sqlite3_wal_checkpoint_v2() returns other than SQLITE_OK.
  6615. ** If no values are available because of an error, they are both set to -1
  6616. ** before returning to communicate this to the caller.
  6617. **
  6618. ** All calls obtain an exclusive "checkpoint" lock on the database file. If
  6619. ** any other process is running a checkpoint operation at the same time, the
  6620. ** lock cannot be obtained and SQLITE_BUSY is returned. Even if there is a
  6621. ** busy-handler configured, it will not be invoked in this case.
  6622. **
  6623. ** The SQLITE_CHECKPOINT_FULL and RESTART modes also obtain the exclusive
  6624. ** "writer" lock on the database file. If the writer lock cannot be obtained
  6625. ** immediately, and a busy-handler is configured, it is invoked and the writer
  6626. ** lock retried until either the busy-handler returns 0 or the lock is
  6627. ** successfully obtained. The busy-handler is also invoked while waiting for
  6628. ** database readers as described above. If the busy-handler returns 0 before
  6629. ** the writer lock is obtained or while waiting for database readers, the
  6630. ** checkpoint operation proceeds from that point in the same way as
  6631. ** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible
  6632. ** without blocking any further. SQLITE_BUSY is returned in this case.
  6633. **
  6634. ** If parameter zDb is NULL or points to a zero length string, then the
  6635. ** specified operation is attempted on all WAL databases. In this case the
  6636. ** values written to output parameters *pnLog and *pnCkpt are undefined. If
  6637. ** an SQLITE_BUSY error is encountered when processing one or more of the
  6638. ** attached WAL databases, the operation is still attempted on any remaining
  6639. ** attached databases and SQLITE_BUSY is returned to the caller. If any other
  6640. ** error occurs while processing an attached database, processing is abandoned
  6641. ** and the error code returned to the caller immediately. If no error
  6642. ** (SQLITE_BUSY or otherwise) is encountered while processing the attached
  6643. ** databases, SQLITE_OK is returned.
  6644. **
  6645. ** If database zDb is the name of an attached database that is not in WAL
  6646. ** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. If
  6647. ** zDb is not NULL (or a zero length string) and is not the name of any
  6648. ** attached database, SQLITE_ERROR is returned to the caller.
  6649. */
  6650. SQLITE_API int sqlite3_wal_checkpoint_v2(
  6651. sqlite3 *db, /* Database handle */
  6652. const char *zDb, /* Name of attached database (or NULL) */
  6653. int eMode, /* SQLITE_CHECKPOINT_* value */
  6654. int *pnLog, /* OUT: Size of WAL log in frames */
  6655. int *pnCkpt /* OUT: Total number of frames checkpointed */
  6656. );
  6657. /*
  6658. ** CAPI3REF: Checkpoint operation parameters
  6659. **
  6660. ** These constants can be used as the 3rd parameter to
  6661. ** [sqlite3_wal_checkpoint_v2()]. See the [sqlite3_wal_checkpoint_v2()]
  6662. ** documentation for additional information about the meaning and use of
  6663. ** each of these values.
  6664. */
  6665. #define SQLITE_CHECKPOINT_PASSIVE 0
  6666. #define SQLITE_CHECKPOINT_FULL 1
  6667. #define SQLITE_CHECKPOINT_RESTART 2
  6668. /*
  6669. ** CAPI3REF: Virtual Table Interface Configuration
  6670. **
  6671. ** This function may be called by either the [xConnect] or [xCreate] method
  6672. ** of a [virtual table] implementation to configure
  6673. ** various facets of the virtual table interface.
  6674. **
  6675. ** If this interface is invoked outside the context of an xConnect or
  6676. ** xCreate virtual table method then the behavior is undefined.
  6677. **
  6678. ** At present, there is only one option that may be configured using
  6679. ** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options
  6680. ** may be added in the future.
  6681. */
  6682. SQLITE_API int sqlite3_vtab_config(sqlite3*, int op, ...);
  6683. /*
  6684. ** CAPI3REF: Virtual Table Configuration Options
  6685. **
  6686. ** These macros define the various options to the
  6687. ** [sqlite3_vtab_config()] interface that [virtual table] implementations
  6688. ** can use to customize and optimize their behavior.
  6689. **
  6690. ** <dl>
  6691. ** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT
  6692. ** <dd>Calls of the form
  6693. ** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
  6694. ** where X is an integer. If X is zero, then the [virtual table] whose
  6695. ** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not
  6696. ** support constraints. In this configuration (which is the default) if
  6697. ** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire
  6698. ** statement is rolled back as if [ON CONFLICT | OR ABORT] had been
  6699. ** specified as part of the users SQL statement, regardless of the actual
  6700. ** ON CONFLICT mode specified.
  6701. **
  6702. ** If X is non-zero, then the virtual table implementation guarantees
  6703. ** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before
  6704. ** any modifications to internal or persistent data structures have been made.
  6705. ** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite
  6706. ** is able to roll back a statement or database transaction, and abandon
  6707. ** or continue processing the current SQL statement as appropriate.
  6708. ** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns
  6709. ** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode
  6710. ** had been ABORT.
  6711. **
  6712. ** Virtual table implementations that are required to handle OR REPLACE
  6713. ** must do so within the [xUpdate] method. If a call to the
  6714. ** [sqlite3_vtab_on_conflict()] function indicates that the current ON
  6715. ** CONFLICT policy is REPLACE, the virtual table implementation should
  6716. ** silently replace the appropriate rows within the xUpdate callback and
  6717. ** return SQLITE_OK. Or, if this is not possible, it may return
  6718. ** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT
  6719. ** constraint handling.
  6720. ** </dl>
  6721. */
  6722. #define SQLITE_VTAB_CONSTRAINT_SUPPORT 1
  6723. /*
  6724. ** CAPI3REF: Determine The Virtual Table Conflict Policy
  6725. **
  6726. ** This function may only be called from within a call to the [xUpdate] method
  6727. ** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The
  6728. ** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
  6729. ** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
  6730. ** of the SQL statement that triggered the call to the [xUpdate] method of the
  6731. ** [virtual table].
  6732. */
  6733. SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *);
  6734. /*
  6735. ** CAPI3REF: Conflict resolution modes
  6736. **
  6737. ** These constants are returned by [sqlite3_vtab_on_conflict()] to
  6738. ** inform a [virtual table] implementation what the [ON CONFLICT] mode
  6739. ** is for the SQL statement being evaluated.
  6740. **
  6741. ** Note that the [SQLITE_IGNORE] constant is also used as a potential
  6742. ** return value from the [sqlite3_set_authorizer()] callback and that
  6743. ** [SQLITE_ABORT] is also a [result code].
  6744. */
  6745. #define SQLITE_ROLLBACK 1
  6746. /* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
  6747. #define SQLITE_FAIL 3
  6748. /* #define SQLITE_ABORT 4 // Also an error code */
  6749. #define SQLITE_REPLACE 5
  6750. /*
  6751. ** Undo the hack that converts floating point types to integer for
  6752. ** builds on processors without floating point support.
  6753. */
  6754. #ifdef SQLITE_OMIT_FLOATING_POINT
  6755. # undef double
  6756. #endif
  6757. #ifdef __cplusplus
  6758. } /* End of the 'extern "C"' block */
  6759. #endif
  6760. #endif
  6761. /*
  6762. ** 2010 August 30
  6763. **
  6764. ** The author disclaims copyright to this source code. In place of
  6765. ** a legal notice, here is a blessing:
  6766. **
  6767. ** May you do good and not evil.
  6768. ** May you find forgiveness for yourself and forgive others.
  6769. ** May you share freely, never taking more than you give.
  6770. **
  6771. *************************************************************************
  6772. */
  6773. #ifndef _SQLITE3RTREE_H_
  6774. #define _SQLITE3RTREE_H_
  6775. #ifdef __cplusplus
  6776. extern "C" {
  6777. #endif
  6778. typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry;
  6779. /*
  6780. ** Register a geometry callback named zGeom that can be used as part of an
  6781. ** R-Tree geometry query as follows:
  6782. **
  6783. ** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...)
  6784. */
  6785. SQLITE_API int sqlite3_rtree_geometry_callback(
  6786. sqlite3 *db,
  6787. const char *zGeom,
  6788. int (*xGeom)(sqlite3_rtree_geometry *, int nCoord, double *aCoord, int *pRes),
  6789. void *pContext
  6790. );
  6791. /*
  6792. ** A pointer to a structure of the following type is passed as the first
  6793. ** argument to callbacks registered using rtree_geometry_callback().
  6794. */
  6795. struct sqlite3_rtree_geometry {
  6796. void *pContext; /* Copy of pContext passed to s_r_g_c() */
  6797. int nParam; /* Size of array aParam[] */
  6798. double *aParam; /* Parameters passed to SQL geom function */
  6799. void *pUser; /* Callback implementation user data */
  6800. void (*xDelUser)(void *); /* Called by SQLite to clean up pUser */
  6801. };
  6802. #ifdef __cplusplus
  6803. } /* end of the 'extern "C"' block */
  6804. #endif
  6805. #endif /* ifndef _SQLITE3RTREE_H_ */