4 ** The author disclaims copyright to this source code. In place of
5 ** a legal notice, here is a blessing:
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.
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.
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.
24 ** The official C-language API documentation for SQLite is derived
25 ** from comments in this file. This file is the authoritative source
26 ** on how SQLite interfaces are supposed to operate.
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.
35 #include <stdarg.h> /* Needed for the definition of va_list */
38 ** Make sure we can call this stuff from C++.
46 ** Provide the ability to override linkage features of the interface.
49 # define SQLITE_EXTERN extern
57 #ifndef SQLITE_STDCALL
58 # define SQLITE_STDCALL
62 ** These no-op macros are used in front of interfaces to mark those
63 ** interfaces as either deprecated or experimental. New applications
64 ** should not use deprecated interfaces - they are supported for backwards
65 ** compatibility only. Application writers should be aware that
66 ** experimental interfaces are subject to change in point releases.
68 ** These macros used to resolve to various kinds of compiler magic that
69 ** would generate warning messages when they were used. But that
70 ** compiler magic ended up generating such a flurry of bug reports
71 ** that we have taken it all out and gone back to using simple
74 #define SQLITE_DEPRECATED
75 #define SQLITE_EXPERIMENTAL
78 ** Ensure these symbols were not defined by some previous header file.
81 # undef SQLITE_VERSION
83 #ifdef SQLITE_VERSION_NUMBER
84 # undef SQLITE_VERSION_NUMBER
88 ** CAPI3REF: Compile-Time Library Version Numbers
90 ** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header
91 ** evaluates to a string literal that is the SQLite version in the
92 ** format "X.Y.Z" where X is the major version number (always 3 for
93 ** SQLite3) and Y is the minor version number and Z is the release number.)^
94 ** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer
95 ** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same
96 ** numbers used in [SQLITE_VERSION].)^
97 ** The SQLITE_VERSION_NUMBER for any given release of SQLite will also
98 ** be larger than the release from which it is derived. Either Y will
99 ** be held constant and Z will be incremented or else Y will be incremented
100 ** and Z will be reset to zero.
102 ** Since version 3.6.18, SQLite source code has been stored in the
103 ** <a href="http://www.fossil-scm.org/">Fossil configuration management
104 ** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to
105 ** a string which identifies a particular check-in of SQLite
106 ** within its configuration management system. ^The SQLITE_SOURCE_ID
107 ** string contains the date and time of the check-in (UTC) and an SHA1
108 ** hash of the entire source tree.
110 ** See also: [sqlite3_libversion()],
111 ** [sqlite3_libversion_number()], [sqlite3_sourceid()],
112 ** [sqlite_version()] and [sqlite_source_id()].
114 #define SQLITE_VERSION "3.9.0"
115 #define SQLITE_VERSION_NUMBER 3009000
116 #define SQLITE_SOURCE_ID "2015-10-14 12:29:53 a721fc0d89495518fe5612e2e3bbc60befd2e90d"
119 ** CAPI3REF: Run-Time Library Version Numbers
120 ** KEYWORDS: sqlite3_version, sqlite3_sourceid
122 ** These interfaces provide the same information as the [SQLITE_VERSION],
123 ** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros
124 ** but are associated with the library instead of the header file. ^(Cautious
125 ** programmers might include assert() statements in their application to
126 ** verify that values returned by these interfaces match the macros in
127 ** the header, and thus ensure that the application is
128 ** compiled with matching library and header files.
131 ** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
132 ** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 );
133 ** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
134 ** </pre></blockquote>)^
136 ** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION]
137 ** macro. ^The sqlite3_libversion() function returns a pointer to the
138 ** to the sqlite3_version[] string constant. The sqlite3_libversion()
139 ** function is provided for use in DLLs since DLL users usually do not have
140 ** direct access to string constants within the DLL. ^The
141 ** sqlite3_libversion_number() function returns an integer equal to
142 ** [SQLITE_VERSION_NUMBER]. ^The sqlite3_sourceid() function returns
143 ** a pointer to a string constant whose value is the same as the
144 ** [SQLITE_SOURCE_ID] C preprocessor macro.
146 ** See also: [sqlite_version()] and [sqlite_source_id()].
148 SQLITE_API SQLITE_EXTERN const char sqlite3_version[];
149 SQLITE_API const char *SQLITE_STDCALL sqlite3_libversion(void);
150 SQLITE_API const char *SQLITE_STDCALL sqlite3_sourceid(void);
151 SQLITE_API int SQLITE_STDCALL sqlite3_libversion_number(void);
154 ** CAPI3REF: Run-Time Library Compilation Options Diagnostics
156 ** ^The sqlite3_compileoption_used() function returns 0 or 1
157 ** indicating whether the specified option was defined at
158 ** compile time. ^The SQLITE_ prefix may be omitted from the
159 ** option name passed to sqlite3_compileoption_used().
161 ** ^The sqlite3_compileoption_get() function allows iterating
162 ** over the list of options that were defined at compile time by
163 ** returning the N-th compile time option string. ^If N is out of range,
164 ** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_
165 ** prefix is omitted from any strings returned by
166 ** sqlite3_compileoption_get().
168 ** ^Support for the diagnostic functions sqlite3_compileoption_used()
169 ** and sqlite3_compileoption_get() may be omitted by specifying the
170 ** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time.
172 ** See also: SQL functions [sqlite_compileoption_used()] and
173 ** [sqlite_compileoption_get()] and the [compile_options pragma].
175 #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
176 SQLITE_API int SQLITE_STDCALL sqlite3_compileoption_used(const char *zOptName);
177 SQLITE_API const char *SQLITE_STDCALL sqlite3_compileoption_get(int N);
181 ** CAPI3REF: Test To See If The Library Is Threadsafe
183 ** ^The sqlite3_threadsafe() function returns zero if and only if
184 ** SQLite was compiled with mutexing code omitted due to the
185 ** [SQLITE_THREADSAFE] compile-time option being set to 0.
187 ** SQLite can be compiled with or without mutexes. When
188 ** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
189 ** are enabled and SQLite is threadsafe. When the
190 ** [SQLITE_THREADSAFE] macro is 0,
191 ** the mutexes are omitted. Without the mutexes, it is not safe
192 ** to use SQLite concurrently from more than one thread.
194 ** Enabling mutexes incurs a measurable performance penalty.
195 ** So if speed is of utmost importance, it makes sense to disable
196 ** the mutexes. But for maximum safety, mutexes should be enabled.
197 ** ^The default behavior is for mutexes to be enabled.
199 ** This interface can be used by an application to make sure that the
200 ** version of SQLite that it is linking against was compiled with
201 ** the desired setting of the [SQLITE_THREADSAFE] macro.
203 ** This interface only reports on the compile-time mutex setting
204 ** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with
205 ** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
206 ** can be fully or partially disabled using a call to [sqlite3_config()]
207 ** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD],
208 ** or [SQLITE_CONFIG_SERIALIZED]. ^(The return value of the
209 ** sqlite3_threadsafe() function shows only the compile-time setting of
210 ** thread safety, not any run-time changes to that setting made by
211 ** sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
212 ** is unchanged by calls to sqlite3_config().)^
214 ** See the [threading mode] documentation for additional information.
216 SQLITE_API int SQLITE_STDCALL sqlite3_threadsafe(void);
219 ** CAPI3REF: Database Connection Handle
220 ** KEYWORDS: {database connection} {database connections}
222 ** Each open SQLite database is represented by a pointer to an instance of
223 ** the opaque structure named "sqlite3". It is useful to think of an sqlite3
224 ** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and
225 ** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
226 ** and [sqlite3_close_v2()] are its destructors. There are many other
227 ** interfaces (such as
228 ** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
229 ** [sqlite3_busy_timeout()] to name but three) that are methods on an
232 typedef struct sqlite3 sqlite3;
235 ** CAPI3REF: 64-Bit Integer Types
236 ** KEYWORDS: sqlite_int64 sqlite_uint64
238 ** Because there is no cross-platform way to specify 64-bit integer types
239 ** SQLite includes typedefs for 64-bit signed and unsigned integers.
241 ** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
242 ** The sqlite_int64 and sqlite_uint64 types are supported for backwards
243 ** compatibility only.
245 ** ^The sqlite3_int64 and sqlite_int64 types can store integer values
246 ** between -9223372036854775808 and +9223372036854775807 inclusive. ^The
247 ** sqlite3_uint64 and sqlite_uint64 types can store integer values
248 ** between 0 and +18446744073709551615 inclusive.
250 #ifdef SQLITE_INT64_TYPE
251 typedef SQLITE_INT64_TYPE sqlite_int64;
252 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
253 #elif defined(_MSC_VER) || defined(__BORLANDC__)
254 typedef __int64 sqlite_int64;
255 typedef unsigned __int64 sqlite_uint64;
257 typedef long long int sqlite_int64;
258 typedef unsigned long long int sqlite_uint64;
260 typedef sqlite_int64 sqlite3_int64;
261 typedef sqlite_uint64 sqlite3_uint64;
264 ** If compiling for a processor that lacks floating point support,
265 ** substitute integer for floating-point.
267 #ifdef SQLITE_OMIT_FLOATING_POINT
268 # define double sqlite3_int64
272 ** CAPI3REF: Closing A Database Connection
273 ** DESTRUCTOR: sqlite3
275 ** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors
276 ** for the [sqlite3] object.
277 ** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if
278 ** the [sqlite3] object is successfully destroyed and all associated
279 ** resources are deallocated.
281 ** ^If the database connection is associated with unfinalized prepared
282 ** statements or unfinished sqlite3_backup objects then sqlite3_close()
283 ** will leave the database connection open and return [SQLITE_BUSY].
284 ** ^If sqlite3_close_v2() is called with unfinalized prepared statements
285 ** and/or unfinished sqlite3_backups, then the database connection becomes
286 ** an unusable "zombie" which will automatically be deallocated when the
287 ** last prepared statement is finalized or the last sqlite3_backup is
288 ** finished. The sqlite3_close_v2() interface is intended for use with
289 ** host languages that are garbage collected, and where the order in which
290 ** destructors are called is arbitrary.
292 ** Applications should [sqlite3_finalize | finalize] all [prepared statements],
293 ** [sqlite3_blob_close | close] all [BLOB handles], and
294 ** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated
295 ** with the [sqlite3] object prior to attempting to close the object. ^If
296 ** sqlite3_close_v2() is called on a [database connection] that still has
297 ** outstanding [prepared statements], [BLOB handles], and/or
298 ** [sqlite3_backup] objects then it returns [SQLITE_OK] and the deallocation
299 ** of resources is deferred until all [prepared statements], [BLOB handles],
300 ** and [sqlite3_backup] objects are also destroyed.
302 ** ^If an [sqlite3] object is destroyed while a transaction is open,
303 ** the transaction is automatically rolled back.
305 ** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)]
306 ** must be either a NULL
307 ** pointer or an [sqlite3] object pointer obtained
308 ** from [sqlite3_open()], [sqlite3_open16()], or
309 ** [sqlite3_open_v2()], and not previously closed.
310 ** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer
311 ** argument is a harmless no-op.
313 SQLITE_API int SQLITE_STDCALL sqlite3_close(sqlite3*);
314 SQLITE_API int SQLITE_STDCALL sqlite3_close_v2(sqlite3*);
317 ** The type for a callback function.
318 ** This is legacy and deprecated. It is included for historical
319 ** compatibility and is not documented.
321 typedef int (*sqlite3_callback)(void*,int,char**, char**);
324 ** CAPI3REF: One-Step Query Execution Interface
327 ** The sqlite3_exec() interface is a convenience wrapper around
328 ** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
329 ** that allows an application to run multiple statements of SQL
330 ** without having to use a lot of C code.
332 ** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
333 ** semicolon-separate SQL statements passed into its 2nd argument,
334 ** in the context of the [database connection] passed in as its 1st
335 ** argument. ^If the callback function of the 3rd argument to
336 ** sqlite3_exec() is not NULL, then it is invoked for each result row
337 ** coming out of the evaluated SQL statements. ^The 4th argument to
338 ** sqlite3_exec() is relayed through to the 1st argument of each
339 ** callback invocation. ^If the callback pointer to sqlite3_exec()
340 ** is NULL, then no callback is ever invoked and result rows are
343 ** ^If an error occurs while evaluating the SQL statements passed into
344 ** sqlite3_exec(), then execution of the current statement stops and
345 ** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec()
346 ** is not NULL then any error message is written into memory obtained
347 ** from [sqlite3_malloc()] and passed back through the 5th parameter.
348 ** To avoid memory leaks, the application should invoke [sqlite3_free()]
349 ** on error message strings returned through the 5th parameter of
350 ** of sqlite3_exec() after the error message string is no longer needed.
351 ** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
352 ** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
353 ** NULL before returning.
355 ** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
356 ** routine returns SQLITE_ABORT without invoking the callback again and
357 ** without running any subsequent SQL statements.
359 ** ^The 2nd argument to the sqlite3_exec() callback function is the
360 ** number of columns in the result. ^The 3rd argument to the sqlite3_exec()
361 ** callback is an array of pointers to strings obtained as if from
362 ** [sqlite3_column_text()], one for each column. ^If an element of a
363 ** result row is NULL then the corresponding string pointer for the
364 ** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the
365 ** sqlite3_exec() callback is an array of pointers to strings where each
366 ** entry represents the name of corresponding result column as obtained
367 ** from [sqlite3_column_name()].
369 ** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
370 ** to an empty string, or a pointer that contains only whitespace and/or
371 ** SQL comments, then no SQL statements are evaluated and the database
377 ** <li> The application must ensure that the 1st parameter to sqlite3_exec()
378 ** is a valid and open [database connection].
379 ** <li> The application must not close the [database connection] specified by
380 ** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
381 ** <li> The application must not modify the SQL statement text passed into
382 ** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
385 SQLITE_API int SQLITE_STDCALL sqlite3_exec(
386 sqlite3*, /* An open database */
387 const char *sql, /* SQL to be evaluated */
388 int (*callback)(void*,int,char**,char**), /* Callback function */
389 void *, /* 1st argument to callback */
390 char **errmsg /* Error msg written here */
394 ** CAPI3REF: Result Codes
395 ** KEYWORDS: {result code definitions}
397 ** Many SQLite functions return an integer result code from the set shown
398 ** here in order to indicate success or failure.
400 ** New error codes may be added in future versions of SQLite.
402 ** See also: [extended result code definitions]
404 #define SQLITE_OK 0 /* Successful result */
405 /* beginning-of-error-codes */
406 #define SQLITE_ERROR 1 /* SQL error or missing database */
407 #define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */
408 #define SQLITE_PERM 3 /* Access permission denied */
409 #define SQLITE_ABORT 4 /* Callback routine requested an abort */
410 #define SQLITE_BUSY 5 /* The database file is locked */
411 #define SQLITE_LOCKED 6 /* A table in the database is locked */
412 #define SQLITE_NOMEM 7 /* A malloc() failed */
413 #define SQLITE_READONLY 8 /* Attempt to write a readonly database */
414 #define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/
415 #define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */
416 #define SQLITE_CORRUPT 11 /* The database disk image is malformed */
417 #define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */
418 #define SQLITE_FULL 13 /* Insertion failed because database is full */
419 #define SQLITE_CANTOPEN 14 /* Unable to open the database file */
420 #define SQLITE_PROTOCOL 15 /* Database lock protocol error */
421 #define SQLITE_EMPTY 16 /* Database is empty */
422 #define SQLITE_SCHEMA 17 /* The database schema changed */
423 #define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */
424 #define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */
425 #define SQLITE_MISMATCH 20 /* Data type mismatch */
426 #define SQLITE_MISUSE 21 /* Library used incorrectly */
427 #define SQLITE_NOLFS 22 /* Uses OS features not supported on host */
428 #define SQLITE_AUTH 23 /* Authorization denied */
429 #define SQLITE_FORMAT 24 /* Auxiliary database format error */
430 #define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */
431 #define SQLITE_NOTADB 26 /* File opened that is not a database file */
432 #define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */
433 #define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */
434 #define SQLITE_ROW 100 /* sqlite3_step() has another row ready */
435 #define SQLITE_DONE 101 /* sqlite3_step() has finished executing */
436 /* end-of-error-codes */
439 ** CAPI3REF: Extended Result Codes
440 ** KEYWORDS: {extended result code definitions}
442 ** In its default configuration, SQLite API routines return one of 30 integer
443 ** [result codes]. However, experience has shown that many of
444 ** these result codes are too coarse-grained. They do not provide as
445 ** much information about problems as programmers might like. In an effort to
446 ** address this, newer versions of SQLite (version 3.3.8 and later) include
447 ** support for additional result codes that provide more detailed information
448 ** about errors. These [extended result codes] are enabled or disabled
449 ** on a per database connection basis using the
450 ** [sqlite3_extended_result_codes()] API. Or, the extended code for
451 ** the most recent error can be obtained using
452 ** [sqlite3_extended_errcode()].
454 #define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8))
455 #define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8))
456 #define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8))
457 #define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8))
458 #define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8))
459 #define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8))
460 #define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8))
461 #define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8))
462 #define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8))
463 #define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8))
464 #define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8))
465 #define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8))
466 #define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8))
467 #define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
468 #define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8))
469 #define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8))
470 #define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8))
471 #define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8))
472 #define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8))
473 #define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8))
474 #define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8))
475 #define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8))
476 #define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8))
477 #define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8))
478 #define SQLITE_IOERR_GETTEMPPATH (SQLITE_IOERR | (25<<8))
479 #define SQLITE_IOERR_CONVPATH (SQLITE_IOERR | (26<<8))
480 #define SQLITE_IOERR_VNODE (SQLITE_IOERR | (27<<8))
481 #define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8))
482 #define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8))
483 #define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY | (2<<8))
484 #define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8))
485 #define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8))
486 #define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8))
487 #define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN | (4<<8))
488 #define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8))
489 #define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8))
490 #define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8))
491 #define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8))
492 #define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8))
493 #define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8))
494 #define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8))
495 #define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8))
496 #define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8))
497 #define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8))
498 #define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8))
499 #define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8))
500 #define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8))
501 #define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8))
502 #define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8))
503 #define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT |(10<<8))
504 #define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8))
505 #define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8))
506 #define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING | (1<<8))
507 #define SQLITE_AUTH_USER (SQLITE_AUTH | (1<<8))
510 ** CAPI3REF: Flags For File Open Operations
512 ** These bit values are intended for use in the
513 ** 3rd parameter to the [sqlite3_open_v2()] interface and
514 ** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
516 #define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */
517 #define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */
518 #define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */
519 #define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */
520 #define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */
521 #define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */
522 #define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */
523 #define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */
524 #define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */
525 #define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */
526 #define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */
527 #define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */
528 #define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */
529 #define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */
530 #define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */
531 #define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */
532 #define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */
533 #define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */
534 #define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */
535 #define SQLITE_OPEN_WAL 0x00080000 /* VFS only */
537 /* Reserved: 0x00F00000 */
540 ** CAPI3REF: Device Characteristics
542 ** The xDeviceCharacteristics method of the [sqlite3_io_methods]
543 ** object returns an integer which is a vector of these
544 ** bit values expressing I/O characteristics of the mass storage
545 ** device that holds the file that the [sqlite3_io_methods]
548 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
549 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
550 ** mean that writes of blocks that are nnn bytes in size and
551 ** are aligned to an address which is an integer multiple of
552 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
553 ** that when data is appended to a file, the data is appended
554 ** first then the size of the file is extended, never the other
555 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
556 ** information is written to disk in the same order as calls
557 ** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
558 ** after reboot following a crash or power loss, the only bytes in a
559 ** file that were written at the application level might have changed
560 ** and that adjacent bytes, even bytes within the same sector are
561 ** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN
562 ** flag indicate that a file cannot be deleted when open. The
563 ** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on
564 ** read-only media and cannot be changed even by processes with
565 ** elevated privileges.
567 #define SQLITE_IOCAP_ATOMIC 0x00000001
568 #define SQLITE_IOCAP_ATOMIC512 0x00000002
569 #define SQLITE_IOCAP_ATOMIC1K 0x00000004
570 #define SQLITE_IOCAP_ATOMIC2K 0x00000008
571 #define SQLITE_IOCAP_ATOMIC4K 0x00000010
572 #define SQLITE_IOCAP_ATOMIC8K 0x00000020
573 #define SQLITE_IOCAP_ATOMIC16K 0x00000040
574 #define SQLITE_IOCAP_ATOMIC32K 0x00000080
575 #define SQLITE_IOCAP_ATOMIC64K 0x00000100
576 #define SQLITE_IOCAP_SAFE_APPEND 0x00000200
577 #define SQLITE_IOCAP_SEQUENTIAL 0x00000400
578 #define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800
579 #define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000
580 #define SQLITE_IOCAP_IMMUTABLE 0x00002000
583 ** CAPI3REF: File Locking Levels
585 ** SQLite uses one of these integer values as the second
586 ** argument to calls it makes to the xLock() and xUnlock() methods
587 ** of an [sqlite3_io_methods] object.
589 #define SQLITE_LOCK_NONE 0
590 #define SQLITE_LOCK_SHARED 1
591 #define SQLITE_LOCK_RESERVED 2
592 #define SQLITE_LOCK_PENDING 3
593 #define SQLITE_LOCK_EXCLUSIVE 4
596 ** CAPI3REF: Synchronization Type Flags
598 ** When SQLite invokes the xSync() method of an
599 ** [sqlite3_io_methods] object it uses a combination of
600 ** these integer values as the second argument.
602 ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
603 ** sync operation only needs to flush data to mass storage. Inode
604 ** information need not be flushed. If the lower four bits of the flag
605 ** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
606 ** If the lower four bits equal SQLITE_SYNC_FULL, that means
607 ** to use Mac OS X style fullsync instead of fsync().
609 ** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
610 ** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
611 ** settings. The [synchronous pragma] determines when calls to the
612 ** xSync VFS method occur and applies uniformly across all platforms.
613 ** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
614 ** energetic or rigorous or forceful the sync operations are and
615 ** only make a difference on Mac OSX for the default SQLite code.
616 ** (Third-party VFS implementations might also make the distinction
617 ** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
618 ** operating systems natively supported by SQLite, only Mac OSX
619 ** cares about the difference.)
621 #define SQLITE_SYNC_NORMAL 0x00002
622 #define SQLITE_SYNC_FULL 0x00003
623 #define SQLITE_SYNC_DATAONLY 0x00010
626 ** CAPI3REF: OS Interface Open File Handle
628 ** An [sqlite3_file] object represents an open file in the
629 ** [sqlite3_vfs | OS interface layer]. Individual OS interface
630 ** implementations will
631 ** want to subclass this object by appending additional fields
632 ** for their own use. The pMethods entry is a pointer to an
633 ** [sqlite3_io_methods] object that defines methods for performing
634 ** I/O operations on the open file.
636 typedef struct sqlite3_file sqlite3_file;
637 struct sqlite3_file {
638 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */
642 ** CAPI3REF: OS Interface File Virtual Methods Object
644 ** Every file opened by the [sqlite3_vfs.xOpen] method populates an
645 ** [sqlite3_file] object (or, more commonly, a subclass of the
646 ** [sqlite3_file] object) with a pointer to an instance of this object.
647 ** This object defines the methods used to perform various operations
648 ** against the open file represented by the [sqlite3_file] object.
650 ** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element
651 ** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
652 ** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The
653 ** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
654 ** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
657 ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
658 ** [SQLITE_SYNC_FULL]. The first choice is the normal fsync().
659 ** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY]
660 ** flag may be ORed in to indicate that only the data of the file
661 ** and not its inode needs to be synced.
663 ** The integer values to xLock() and xUnlock() are one of
665 ** <li> [SQLITE_LOCK_NONE],
666 ** <li> [SQLITE_LOCK_SHARED],
667 ** <li> [SQLITE_LOCK_RESERVED],
668 ** <li> [SQLITE_LOCK_PENDING], or
669 ** <li> [SQLITE_LOCK_EXCLUSIVE].
671 ** xLock() increases the lock. xUnlock() decreases the lock.
672 ** The xCheckReservedLock() method checks whether any database connection,
673 ** either in this process or in some other process, is holding a RESERVED,
674 ** PENDING, or EXCLUSIVE lock on the file. It returns true
675 ** if such a lock exists and false otherwise.
677 ** The xFileControl() method is a generic interface that allows custom
678 ** VFS implementations to directly control an open file using the
679 ** [sqlite3_file_control()] interface. The second "op" argument is an
680 ** integer opcode. The third argument is a generic pointer intended to
681 ** point to a structure that may contain arguments or space in which to
682 ** write return values. Potential uses for xFileControl() might be
683 ** functions to enable blocking locks with timeouts, to change the
684 ** locking strategy (for example to use dot-file locks), to inquire
685 ** about the status of a lock, or to break stale locks. The SQLite
686 ** core reserves all opcodes less than 100 for its own use.
687 ** A [file control opcodes | list of opcodes] less than 100 is available.
688 ** Applications that define a custom xFileControl method should use opcodes
689 ** greater than 100 to avoid conflicts. VFS implementations should
690 ** return [SQLITE_NOTFOUND] for file control opcodes that they do not
693 ** The xSectorSize() method returns the sector size of the
694 ** device that underlies the file. The sector size is the
695 ** minimum write that can be performed without disturbing
696 ** other bytes in the file. The xDeviceCharacteristics()
697 ** method returns a bit vector describing behaviors of the
698 ** underlying device:
701 ** <li> [SQLITE_IOCAP_ATOMIC]
702 ** <li> [SQLITE_IOCAP_ATOMIC512]
703 ** <li> [SQLITE_IOCAP_ATOMIC1K]
704 ** <li> [SQLITE_IOCAP_ATOMIC2K]
705 ** <li> [SQLITE_IOCAP_ATOMIC4K]
706 ** <li> [SQLITE_IOCAP_ATOMIC8K]
707 ** <li> [SQLITE_IOCAP_ATOMIC16K]
708 ** <li> [SQLITE_IOCAP_ATOMIC32K]
709 ** <li> [SQLITE_IOCAP_ATOMIC64K]
710 ** <li> [SQLITE_IOCAP_SAFE_APPEND]
711 ** <li> [SQLITE_IOCAP_SEQUENTIAL]
714 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
715 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
716 ** mean that writes of blocks that are nnn bytes in size and
717 ** are aligned to an address which is an integer multiple of
718 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
719 ** that when data is appended to a file, the data is appended
720 ** first then the size of the file is extended, never the other
721 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
722 ** information is written to disk in the same order as calls
725 ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
726 ** in the unread portions of the buffer with zeros. A VFS that
727 ** fails to zero-fill short reads might seem to work. However,
728 ** failure to zero-fill short reads will eventually lead to
729 ** database corruption.
731 typedef struct sqlite3_io_methods sqlite3_io_methods;
732 struct sqlite3_io_methods {
734 int (*xClose)(sqlite3_file*);
735 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
736 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
737 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
738 int (*xSync)(sqlite3_file*, int flags);
739 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
740 int (*xLock)(sqlite3_file*, int);
741 int (*xUnlock)(sqlite3_file*, int);
742 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
743 int (*xFileControl)(sqlite3_file*, int op, void *pArg);
744 int (*xSectorSize)(sqlite3_file*);
745 int (*xDeviceCharacteristics)(sqlite3_file*);
746 /* Methods above are valid for version 1 */
747 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
748 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
749 void (*xShmBarrier)(sqlite3_file*);
750 int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
751 /* Methods above are valid for version 2 */
752 int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp);
753 int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p);
754 /* Methods above are valid for version 3 */
755 /* Additional methods may be added in future releases */
759 ** CAPI3REF: Standard File Control Opcodes
760 ** KEYWORDS: {file control opcodes} {file control opcode}
762 ** These integer constants are opcodes for the xFileControl method
763 ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
767 ** <li>[[SQLITE_FCNTL_LOCKSTATE]]
768 ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This
769 ** opcode causes the xFileControl method to write the current state of
770 ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
771 ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
772 ** into an integer that the pArg argument points to. This capability
773 ** is used during testing and is only available when the SQLITE_TEST
774 ** compile-time option is used.
776 ** <li>[[SQLITE_FCNTL_SIZE_HINT]]
777 ** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
778 ** layer a hint of how large the database file will grow to be during the
779 ** current transaction. This hint is not guaranteed to be accurate but it
780 ** is often close. The underlying VFS might choose to preallocate database
781 ** file space based on this hint in order to help writes to the database
784 ** <li>[[SQLITE_FCNTL_CHUNK_SIZE]]
785 ** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
786 ** extends and truncates the database file in chunks of a size specified
787 ** by the user. The fourth argument to [sqlite3_file_control()] should
788 ** point to an integer (type int) containing the new chunk-size to use
789 ** for the nominated database. Allocating database file space in large
790 ** chunks (say 1MB at a time), may reduce file-system fragmentation and
791 ** improve performance on some systems.
793 ** <li>[[SQLITE_FCNTL_FILE_POINTER]]
794 ** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
795 ** to the [sqlite3_file] object associated with a particular database
796 ** connection. See the [sqlite3_file_control()] documentation for
797 ** additional information.
799 ** <li>[[SQLITE_FCNTL_SYNC_OMITTED]]
802 ** <li>[[SQLITE_FCNTL_SYNC]]
803 ** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and
804 ** sent to the VFS immediately before the xSync method is invoked on a
805 ** database file descriptor. Or, if the xSync method is not invoked
806 ** because the user has configured SQLite with
807 ** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place
808 ** of the xSync method. In most cases, the pointer argument passed with
809 ** this file-control is NULL. However, if the database file is being synced
810 ** as part of a multi-database commit, the argument points to a nul-terminated
811 ** string containing the transactions master-journal file name. VFSes that
812 ** do not need this signal should silently ignore this opcode. Applications
813 ** should not call [sqlite3_file_control()] with this opcode as doing so may
814 ** disrupt the operation of the specialized VFSes that do require it.
816 ** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]]
817 ** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite
818 ** and sent to the VFS after a transaction has been committed immediately
819 ** but before the database is unlocked. VFSes that do not need this signal
820 ** should silently ignore this opcode. Applications should not call
821 ** [sqlite3_file_control()] with this opcode as doing so may disrupt the
822 ** operation of the specialized VFSes that do require it.
824 ** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]]
825 ** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
826 ** retry counts and intervals for certain disk I/O operations for the
827 ** windows [VFS] in order to provide robustness in the presence of
828 ** anti-virus programs. By default, the windows VFS will retry file read,
829 ** file write, and file delete operations up to 10 times, with a delay
830 ** of 25 milliseconds before the first retry and with the delay increasing
831 ** by an additional 25 milliseconds with each subsequent retry. This
832 ** opcode allows these two values (10 retries and 25 milliseconds of delay)
833 ** to be adjusted. The values are changed for all database connections
834 ** within the same process. The argument is a pointer to an array of two
835 ** integers where the first integer i the new retry count and the second
836 ** integer is the delay. If either integer is negative, then the setting
837 ** is not changed but instead the prior value of that setting is written
838 ** into the array entry, allowing the current retry settings to be
839 ** interrogated. The zDbName parameter is ignored.
841 ** <li>[[SQLITE_FCNTL_PERSIST_WAL]]
842 ** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
843 ** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary
844 ** write ahead log and shared memory files used for transaction control
845 ** are automatically deleted when the latest connection to the database
846 ** closes. Setting persistent WAL mode causes those files to persist after
847 ** close. Persisting the files is useful when other processes that do not
848 ** have write permission on the directory containing the database file want
849 ** to read the database file, as the WAL and shared memory files must exist
850 ** in order for the database to be readable. The fourth parameter to
851 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
852 ** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
853 ** WAL mode. If the integer is -1, then it is overwritten with the current
854 ** WAL persistence setting.
856 ** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]]
857 ** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
858 ** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting
859 ** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
860 ** xDeviceCharacteristics methods. The fourth parameter to
861 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
862 ** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
863 ** mode. If the integer is -1, then it is overwritten with the current
864 ** zero-damage mode setting.
866 ** <li>[[SQLITE_FCNTL_OVERWRITE]]
867 ** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
868 ** a write transaction to indicate that, unless it is rolled back for some
869 ** reason, the entire database file will be overwritten by the current
870 ** transaction. This is used by VACUUM operations.
872 ** <li>[[SQLITE_FCNTL_VFSNAME]]
873 ** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
874 ** all [VFSes] in the VFS stack. The names are of all VFS shims and the
875 ** final bottom-level VFS are written into memory obtained from
876 ** [sqlite3_malloc()] and the result is stored in the char* variable
877 ** that the fourth parameter of [sqlite3_file_control()] points to.
878 ** The caller is responsible for freeing the memory when done. As with
879 ** all file-control actions, there is no guarantee that this will actually
880 ** do anything. Callers should initialize the char* variable to a NULL
881 ** pointer in case this file-control is not implemented. This file-control
882 ** is intended for diagnostic use only.
884 ** <li>[[SQLITE_FCNTL_PRAGMA]]
885 ** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA]
886 ** file control is sent to the open [sqlite3_file] object corresponding
887 ** to the database file to which the pragma statement refers. ^The argument
888 ** to the [SQLITE_FCNTL_PRAGMA] file control is an array of
889 ** pointers to strings (char**) in which the second element of the array
890 ** is the name of the pragma and the third element is the argument to the
891 ** pragma or NULL if the pragma has no argument. ^The handler for an
892 ** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element
893 ** of the char** argument point to a string obtained from [sqlite3_mprintf()]
894 ** or the equivalent and that string will become the result of the pragma or
895 ** the error message if the pragma fails. ^If the
896 ** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal
897 ** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA]
898 ** file control returns [SQLITE_OK], then the parser assumes that the
899 ** VFS has handled the PRAGMA itself and the parser generates a no-op
900 ** prepared statement if result string is NULL, or that returns a copy
901 ** of the result string if the string is non-NULL.
902 ** ^If the [SQLITE_FCNTL_PRAGMA] file control returns
903 ** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means
904 ** that the VFS encountered an error while handling the [PRAGMA] and the
905 ** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA]
906 ** file control occurs at the beginning of pragma statement analysis and so
907 ** it is able to override built-in [PRAGMA] statements.
909 ** <li>[[SQLITE_FCNTL_BUSYHANDLER]]
910 ** ^The [SQLITE_FCNTL_BUSYHANDLER]
911 ** file-control may be invoked by SQLite on the database file handle
912 ** shortly after it is opened in order to provide a custom VFS with access
913 ** to the connections busy-handler callback. The argument is of type (void **)
914 ** - an array of two (void *) values. The first (void *) actually points
915 ** to a function of type (int (*)(void *)). In order to invoke the connections
916 ** busy-handler, this function should be invoked with the second (void *) in
917 ** the array as the only argument. If it returns non-zero, then the operation
918 ** should be retried. If it returns zero, the custom VFS should abandon the
919 ** current operation.
921 ** <li>[[SQLITE_FCNTL_TEMPFILENAME]]
922 ** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control
923 ** to have SQLite generate a
924 ** temporary filename using the same algorithm that is followed to generate
925 ** temporary filenames for TEMP tables and other internal uses. The
926 ** argument should be a char** which will be filled with the filename
927 ** written into memory obtained from [sqlite3_malloc()]. The caller should
928 ** invoke [sqlite3_free()] on the result to avoid a memory leak.
930 ** <li>[[SQLITE_FCNTL_MMAP_SIZE]]
931 ** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the
932 ** maximum number of bytes that will be used for memory-mapped I/O.
933 ** The argument is a pointer to a value of type sqlite3_int64 that
934 ** is an advisory maximum number of bytes in the file to memory map. The
935 ** pointer is overwritten with the old value. The limit is not changed if
936 ** the value originally pointed to is negative, and so the current limit
937 ** can be queried by passing in a pointer to a negative number. This
938 ** file-control is used internally to implement [PRAGMA mmap_size].
940 ** <li>[[SQLITE_FCNTL_TRACE]]
941 ** The [SQLITE_FCNTL_TRACE] file control provides advisory information
942 ** to the VFS about what the higher layers of the SQLite stack are doing.
943 ** This file control is used by some VFS activity tracing [shims].
944 ** The argument is a zero-terminated string. Higher layers in the
945 ** SQLite stack may generate instances of this file control if
946 ** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled.
948 ** <li>[[SQLITE_FCNTL_HAS_MOVED]]
949 ** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a
950 ** pointer to an integer and it writes a boolean into that integer depending
951 ** on whether or not the file has been renamed, moved, or deleted since it
954 ** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]]
955 ** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This
956 ** opcode causes the xFileControl method to swap the file handle with the one
957 ** pointed to by the pArg argument. This capability is used during testing
958 ** and only needs to be supported when SQLITE_TEST is defined.
960 ** <li>[[SQLITE_FCNTL_WAL_BLOCK]]
961 ** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might
962 ** be advantageous to block on the next WAL lock if the lock is not immediately
963 ** available. The WAL subsystem issues this signal during rare
964 ** circumstances in order to fix a problem with priority inversion.
965 ** Applications should <em>not</em> use this file-control.
967 ** <li>[[SQLITE_FCNTL_ZIPVFS]]
968 ** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other
969 ** VFS should return SQLITE_NOTFOUND for this opcode.
971 ** <li>[[SQLITE_FCNTL_RBU]]
972 ** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by
973 ** the RBU extension only. All other VFS should return SQLITE_NOTFOUND for
977 #define SQLITE_FCNTL_LOCKSTATE 1
978 #define SQLITE_FCNTL_GET_LOCKPROXYFILE 2
979 #define SQLITE_FCNTL_SET_LOCKPROXYFILE 3
980 #define SQLITE_FCNTL_LAST_ERRNO 4
981 #define SQLITE_FCNTL_SIZE_HINT 5
982 #define SQLITE_FCNTL_CHUNK_SIZE 6
983 #define SQLITE_FCNTL_FILE_POINTER 7
984 #define SQLITE_FCNTL_SYNC_OMITTED 8
985 #define SQLITE_FCNTL_WIN32_AV_RETRY 9
986 #define SQLITE_FCNTL_PERSIST_WAL 10
987 #define SQLITE_FCNTL_OVERWRITE 11
988 #define SQLITE_FCNTL_VFSNAME 12
989 #define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13
990 #define SQLITE_FCNTL_PRAGMA 14
991 #define SQLITE_FCNTL_BUSYHANDLER 15
992 #define SQLITE_FCNTL_TEMPFILENAME 16
993 #define SQLITE_FCNTL_MMAP_SIZE 18
994 #define SQLITE_FCNTL_TRACE 19
995 #define SQLITE_FCNTL_HAS_MOVED 20
996 #define SQLITE_FCNTL_SYNC 21
997 #define SQLITE_FCNTL_COMMIT_PHASETWO 22
998 #define SQLITE_FCNTL_WIN32_SET_HANDLE 23
999 #define SQLITE_FCNTL_WAL_BLOCK 24
1000 #define SQLITE_FCNTL_ZIPVFS 25
1001 #define SQLITE_FCNTL_RBU 26
1003 /* deprecated names */
1004 #define SQLITE_GET_LOCKPROXYFILE SQLITE_FCNTL_GET_LOCKPROXYFILE
1005 #define SQLITE_SET_LOCKPROXYFILE SQLITE_FCNTL_SET_LOCKPROXYFILE
1006 #define SQLITE_LAST_ERRNO SQLITE_FCNTL_LAST_ERRNO
1010 ** CAPI3REF: Mutex Handle
1012 ** The mutex module within SQLite defines [sqlite3_mutex] to be an
1013 ** abstract type for a mutex object. The SQLite core never looks
1014 ** at the internal representation of an [sqlite3_mutex]. It only
1015 ** deals with pointers to the [sqlite3_mutex] object.
1017 ** Mutexes are created using [sqlite3_mutex_alloc()].
1019 typedef struct sqlite3_mutex sqlite3_mutex;
1022 ** CAPI3REF: OS Interface Object
1024 ** An instance of the sqlite3_vfs object defines the interface between
1025 ** the SQLite core and the underlying operating system. The "vfs"
1026 ** in the name of the object stands for "virtual file system". See
1027 ** the [VFS | VFS documentation] for further information.
1029 ** The value of the iVersion field is initially 1 but may be larger in
1030 ** future versions of SQLite. Additional fields may be appended to this
1031 ** object when the iVersion value is increased. Note that the structure
1032 ** of the sqlite3_vfs object changes in the transaction between
1033 ** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not
1036 ** The szOsFile field is the size of the subclassed [sqlite3_file]
1037 ** structure used by this VFS. mxPathname is the maximum length of
1038 ** a pathname in this VFS.
1040 ** Registered sqlite3_vfs objects are kept on a linked list formed by
1041 ** the pNext pointer. The [sqlite3_vfs_register()]
1042 ** and [sqlite3_vfs_unregister()] interfaces manage this list
1043 ** in a thread-safe way. The [sqlite3_vfs_find()] interface
1044 ** searches the list. Neither the application code nor the VFS
1045 ** implementation should use the pNext pointer.
1047 ** The pNext field is the only field in the sqlite3_vfs
1048 ** structure that SQLite will ever modify. SQLite will only access
1049 ** or modify this field while holding a particular static mutex.
1050 ** The application should never modify anything within the sqlite3_vfs
1051 ** object once the object has been registered.
1053 ** The zName field holds the name of the VFS module. The name must
1054 ** be unique across all VFS modules.
1056 ** [[sqlite3_vfs.xOpen]]
1057 ** ^SQLite guarantees that the zFilename parameter to xOpen
1058 ** is either a NULL pointer or string obtained
1059 ** from xFullPathname() with an optional suffix added.
1060 ** ^If a suffix is added to the zFilename parameter, it will
1061 ** consist of a single "-" character followed by no more than
1062 ** 11 alphanumeric and/or "-" characters.
1063 ** ^SQLite further guarantees that
1064 ** the string will be valid and unchanged until xClose() is
1065 ** called. Because of the previous sentence,
1066 ** the [sqlite3_file] can safely store a pointer to the
1067 ** filename if it needs to remember the filename for some reason.
1068 ** If the zFilename parameter to xOpen is a NULL pointer then xOpen
1069 ** must invent its own temporary name for the file. ^Whenever the
1070 ** xFilename parameter is NULL it will also be the case that the
1071 ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
1073 ** The flags argument to xOpen() includes all bits set in
1074 ** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()]
1075 ** or [sqlite3_open16()] is used, then flags includes at least
1076 ** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE].
1077 ** If xOpen() opens a file read-only then it sets *pOutFlags to
1078 ** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set.
1080 ** ^(SQLite will also add one of the following flags to the xOpen()
1081 ** call, depending on the object being opened:
1084 ** <li> [SQLITE_OPEN_MAIN_DB]
1085 ** <li> [SQLITE_OPEN_MAIN_JOURNAL]
1086 ** <li> [SQLITE_OPEN_TEMP_DB]
1087 ** <li> [SQLITE_OPEN_TEMP_JOURNAL]
1088 ** <li> [SQLITE_OPEN_TRANSIENT_DB]
1089 ** <li> [SQLITE_OPEN_SUBJOURNAL]
1090 ** <li> [SQLITE_OPEN_MASTER_JOURNAL]
1091 ** <li> [SQLITE_OPEN_WAL]
1094 ** The file I/O implementation can use the object type flags to
1095 ** change the way it deals with files. For example, an application
1096 ** that does not care about crash recovery or rollback might make
1097 ** the open of a journal file a no-op. Writes to this journal would
1098 ** also be no-ops, and any attempt to read the journal would return
1099 ** SQLITE_IOERR. Or the implementation might recognize that a database
1100 ** file will be doing page-aligned sector reads and writes in a random
1101 ** order and set up its I/O subsystem accordingly.
1103 ** SQLite might also add one of the following flags to the xOpen method:
1106 ** <li> [SQLITE_OPEN_DELETEONCLOSE]
1107 ** <li> [SQLITE_OPEN_EXCLUSIVE]
1110 ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
1111 ** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE]
1112 ** will be set for TEMP databases and their journals, transient
1113 ** databases, and subjournals.
1115 ** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
1116 ** with the [SQLITE_OPEN_CREATE] flag, which are both directly
1117 ** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
1118 ** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
1119 ** SQLITE_OPEN_CREATE, is used to indicate that file should always
1120 ** be created, and that it is an error if it already exists.
1121 ** It is <i>not</i> used to indicate the file should be opened
1122 ** for exclusive access.
1124 ** ^At least szOsFile bytes of memory are allocated by SQLite
1125 ** to hold the [sqlite3_file] structure passed as the third
1126 ** argument to xOpen. The xOpen method does not have to
1127 ** allocate the structure; it should just fill it in. Note that
1128 ** the xOpen method must set the sqlite3_file.pMethods to either
1129 ** a valid [sqlite3_io_methods] object or to NULL. xOpen must do
1130 ** this even if the open fails. SQLite expects that the sqlite3_file.pMethods
1131 ** element will be valid after xOpen returns regardless of the success
1132 ** or failure of the xOpen call.
1134 ** [[sqlite3_vfs.xAccess]]
1135 ** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
1136 ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
1137 ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
1138 ** to test whether a file is at least readable. The file can be a
1141 ** ^SQLite will always allocate at least mxPathname+1 bytes for the
1142 ** output buffer xFullPathname. The exact size of the output buffer
1143 ** is also passed as a parameter to both methods. If the output buffer
1144 ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
1145 ** handled as a fatal error by SQLite, vfs implementations should endeavor
1146 ** to prevent this by setting mxPathname to a sufficiently large value.
1148 ** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
1149 ** interfaces are not strictly a part of the filesystem, but they are
1150 ** included in the VFS structure for completeness.
1151 ** The xRandomness() function attempts to return nBytes bytes
1152 ** of good-quality randomness into zOut. The return value is
1153 ** the actual number of bytes of randomness obtained.
1154 ** The xSleep() method causes the calling thread to sleep for at
1155 ** least the number of microseconds given. ^The xCurrentTime()
1156 ** method returns a Julian Day Number for the current date and time as
1157 ** a floating point value.
1158 ** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
1159 ** Day Number multiplied by 86400000 (the number of milliseconds in
1161 ** ^SQLite will use the xCurrentTimeInt64() method to get the current
1162 ** date and time if that method is available (if iVersion is 2 or
1163 ** greater and the function pointer is not NULL) and will fall back
1164 ** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
1166 ** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
1167 ** are not used by the SQLite core. These optional interfaces are provided
1168 ** by some VFSes to facilitate testing of the VFS code. By overriding
1169 ** system calls with functions under its control, a test program can
1170 ** simulate faults and error conditions that would otherwise be difficult
1171 ** or impossible to induce. The set of system calls that can be overridden
1172 ** varies from one VFS to another, and from one version of the same VFS to the
1173 ** next. Applications that use these interfaces must be prepared for any
1174 ** or all of these interfaces to be NULL or for their behavior to change
1175 ** from one release to the next. Applications must not attempt to access
1176 ** any of these methods if the iVersion of the VFS is less than 3.
1178 typedef struct sqlite3_vfs sqlite3_vfs;
1179 typedef void (*sqlite3_syscall_ptr)(void);
1180 struct sqlite3_vfs {
1181 int iVersion; /* Structure version number (currently 3) */
1182 int szOsFile; /* Size of subclassed sqlite3_file */
1183 int mxPathname; /* Maximum file pathname length */
1184 sqlite3_vfs *pNext; /* Next registered VFS */
1185 const char *zName; /* Name of this virtual file system */
1186 void *pAppData; /* Pointer to application-specific data */
1187 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
1188 int flags, int *pOutFlags);
1189 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
1190 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
1191 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
1192 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
1193 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
1194 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
1195 void (*xDlClose)(sqlite3_vfs*, void*);
1196 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
1197 int (*xSleep)(sqlite3_vfs*, int microseconds);
1198 int (*xCurrentTime)(sqlite3_vfs*, double*);
1199 int (*xGetLastError)(sqlite3_vfs*, int, char *);
1201 ** The methods above are in version 1 of the sqlite_vfs object
1202 ** definition. Those that follow are added in version 2 or later
1204 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
1206 ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
1207 ** Those below are for version 3 and greater.
1209 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
1210 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
1211 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
1213 ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
1214 ** New fields may be appended in figure versions. The iVersion
1215 ** value will increment whenever this happens.
1220 ** CAPI3REF: Flags for the xAccess VFS method
1222 ** These integer constants can be used as the third parameter to
1223 ** the xAccess method of an [sqlite3_vfs] object. They determine
1224 ** what kind of permissions the xAccess method is looking for.
1225 ** With SQLITE_ACCESS_EXISTS, the xAccess method
1226 ** simply checks whether the file exists.
1227 ** With SQLITE_ACCESS_READWRITE, the xAccess method
1228 ** checks whether the named directory is both readable and writable
1229 ** (in other words, if files can be added, removed, and renamed within
1231 ** The SQLITE_ACCESS_READWRITE constant is currently used only by the
1232 ** [temp_store_directory pragma], though this could change in a future
1233 ** release of SQLite.
1234 ** With SQLITE_ACCESS_READ, the xAccess method
1235 ** checks whether the file is readable. The SQLITE_ACCESS_READ constant is
1236 ** currently unused, though it might be used in a future release of
1239 #define SQLITE_ACCESS_EXISTS 0
1240 #define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */
1241 #define SQLITE_ACCESS_READ 2 /* Unused */
1244 ** CAPI3REF: Flags for the xShmLock VFS method
1246 ** These integer constants define the various locking operations
1247 ** allowed by the xShmLock method of [sqlite3_io_methods]. The
1248 ** following are the only legal combinations of flags to the
1252 ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
1253 ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
1254 ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
1255 ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
1258 ** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
1259 ** was given on the corresponding lock.
1261 ** The xShmLock method can transition between unlocked and SHARED or
1262 ** between unlocked and EXCLUSIVE. It cannot transition between SHARED
1265 #define SQLITE_SHM_UNLOCK 1
1266 #define SQLITE_SHM_LOCK 2
1267 #define SQLITE_SHM_SHARED 4
1268 #define SQLITE_SHM_EXCLUSIVE 8
1271 ** CAPI3REF: Maximum xShmLock index
1273 ** The xShmLock method on [sqlite3_io_methods] may use values
1274 ** between 0 and this upper bound as its "offset" argument.
1275 ** The SQLite core will never attempt to acquire or release a
1276 ** lock outside of this range
1278 #define SQLITE_SHM_NLOCK 8
1282 ** CAPI3REF: Initialize The SQLite Library
1284 ** ^The sqlite3_initialize() routine initializes the
1285 ** SQLite library. ^The sqlite3_shutdown() routine
1286 ** deallocates any resources that were allocated by sqlite3_initialize().
1287 ** These routines are designed to aid in process initialization and
1288 ** shutdown on embedded systems. Workstation applications using
1289 ** SQLite normally do not need to invoke either of these routines.
1291 ** A call to sqlite3_initialize() is an "effective" call if it is
1292 ** the first time sqlite3_initialize() is invoked during the lifetime of
1293 ** the process, or if it is the first time sqlite3_initialize() is invoked
1294 ** following a call to sqlite3_shutdown(). ^(Only an effective call
1295 ** of sqlite3_initialize() does any initialization. All other calls
1296 ** are harmless no-ops.)^
1298 ** A call to sqlite3_shutdown() is an "effective" call if it is the first
1299 ** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only
1300 ** an effective call to sqlite3_shutdown() does any deinitialization.
1301 ** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
1303 ** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
1304 ** is not. The sqlite3_shutdown() interface must only be called from a
1305 ** single thread. All open [database connections] must be closed and all
1306 ** other SQLite resources must be deallocated prior to invoking
1307 ** sqlite3_shutdown().
1309 ** Among other things, ^sqlite3_initialize() will invoke
1310 ** sqlite3_os_init(). Similarly, ^sqlite3_shutdown()
1311 ** will invoke sqlite3_os_end().
1313 ** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
1314 ** ^If for some reason, sqlite3_initialize() is unable to initialize
1315 ** the library (perhaps it is unable to allocate a needed resource such
1316 ** as a mutex) it returns an [error code] other than [SQLITE_OK].
1318 ** ^The sqlite3_initialize() routine is called internally by many other
1319 ** SQLite interfaces so that an application usually does not need to
1320 ** invoke sqlite3_initialize() directly. For example, [sqlite3_open()]
1321 ** calls sqlite3_initialize() so the SQLite library will be automatically
1322 ** initialized when [sqlite3_open()] is called if it has not be initialized
1323 ** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
1324 ** compile-time option, then the automatic calls to sqlite3_initialize()
1325 ** are omitted and the application must call sqlite3_initialize() directly
1326 ** prior to using any other SQLite interface. For maximum portability,
1327 ** it is recommended that applications always invoke sqlite3_initialize()
1328 ** directly prior to using any other SQLite interface. Future releases
1329 ** of SQLite may require this. In other words, the behavior exhibited
1330 ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
1331 ** default behavior in some future release of SQLite.
1333 ** The sqlite3_os_init() routine does operating-system specific
1334 ** initialization of the SQLite library. The sqlite3_os_end()
1335 ** routine undoes the effect of sqlite3_os_init(). Typical tasks
1336 ** performed by these routines include allocation or deallocation
1337 ** of static resources, initialization of global variables,
1338 ** setting up a default [sqlite3_vfs] module, or setting up
1339 ** a default configuration using [sqlite3_config()].
1341 ** The application should never invoke either sqlite3_os_init()
1342 ** or sqlite3_os_end() directly. The application should only invoke
1343 ** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init()
1344 ** interface is called automatically by sqlite3_initialize() and
1345 ** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate
1346 ** implementations for sqlite3_os_init() and sqlite3_os_end()
1347 ** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
1348 ** When [custom builds | built for other platforms]
1349 ** (using the [SQLITE_OS_OTHER=1] compile-time
1350 ** option) the application must supply a suitable implementation for
1351 ** sqlite3_os_init() and sqlite3_os_end(). An application-supplied
1352 ** implementation of sqlite3_os_init() or sqlite3_os_end()
1353 ** must return [SQLITE_OK] on success and some other [error code] upon
1356 SQLITE_API int SQLITE_STDCALL sqlite3_initialize(void);
1357 SQLITE_API int SQLITE_STDCALL sqlite3_shutdown(void);
1358 SQLITE_API int SQLITE_STDCALL sqlite3_os_init(void);
1359 SQLITE_API int SQLITE_STDCALL sqlite3_os_end(void);
1362 ** CAPI3REF: Configuring The SQLite Library
1364 ** The sqlite3_config() interface is used to make global configuration
1365 ** changes to SQLite in order to tune SQLite to the specific needs of
1366 ** the application. The default configuration is recommended for most
1367 ** applications and so this routine is usually not necessary. It is
1368 ** provided to support rare applications with unusual needs.
1370 ** <b>The sqlite3_config() interface is not threadsafe. The application
1371 ** must ensure that no other SQLite interfaces are invoked by other
1372 ** threads while sqlite3_config() is running.</b>
1374 ** The sqlite3_config() interface
1375 ** may only be invoked prior to library initialization using
1376 ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
1377 ** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
1378 ** [sqlite3_shutdown()] then it will return SQLITE_MISUSE.
1379 ** Note, however, that ^sqlite3_config() can be called as part of the
1380 ** implementation of an application-defined [sqlite3_os_init()].
1382 ** The first argument to sqlite3_config() is an integer
1383 ** [configuration option] that determines
1384 ** what property of SQLite is to be configured. Subsequent arguments
1385 ** vary depending on the [configuration option]
1386 ** in the first argument.
1388 ** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
1389 ** ^If the option is unknown or SQLite is unable to set the option
1390 ** then this routine returns a non-zero [error code].
1392 SQLITE_API int SQLITE_CDECL sqlite3_config(int, ...);
1395 ** CAPI3REF: Configure database connections
1398 ** The sqlite3_db_config() interface is used to make configuration
1399 ** changes to a [database connection]. The interface is similar to
1400 ** [sqlite3_config()] except that the changes apply to a single
1401 ** [database connection] (specified in the first argument).
1403 ** The second argument to sqlite3_db_config(D,V,...) is the
1404 ** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code
1405 ** that indicates what aspect of the [database connection] is being configured.
1406 ** Subsequent arguments vary depending on the configuration verb.
1408 ** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
1409 ** the call is considered successful.
1411 SQLITE_API int SQLITE_CDECL sqlite3_db_config(sqlite3*, int op, ...);
1414 ** CAPI3REF: Memory Allocation Routines
1416 ** An instance of this object defines the interface between SQLite
1417 ** and low-level memory allocation routines.
1419 ** This object is used in only one place in the SQLite interface.
1420 ** A pointer to an instance of this object is the argument to
1421 ** [sqlite3_config()] when the configuration option is
1422 ** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].
1423 ** By creating an instance of this object
1424 ** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
1425 ** during configuration, an application can specify an alternative
1426 ** memory allocation subsystem for SQLite to use for all of its
1427 ** dynamic memory needs.
1429 ** Note that SQLite comes with several [built-in memory allocators]
1430 ** that are perfectly adequate for the overwhelming majority of applications
1431 ** and that this object is only useful to a tiny minority of applications
1432 ** with specialized memory allocation requirements. This object is
1433 ** also used during testing of SQLite in order to specify an alternative
1434 ** memory allocator that simulates memory out-of-memory conditions in
1435 ** order to verify that SQLite recovers gracefully from such
1438 ** The xMalloc, xRealloc, and xFree methods must work like the
1439 ** malloc(), realloc() and free() functions from the standard C library.
1440 ** ^SQLite guarantees that the second argument to
1441 ** xRealloc is always a value returned by a prior call to xRoundup.
1443 ** xSize should return the allocated size of a memory allocation
1444 ** previously obtained from xMalloc or xRealloc. The allocated size
1445 ** is always at least as big as the requested size but may be larger.
1447 ** The xRoundup method returns what would be the allocated size of
1448 ** a memory allocation given a particular requested size. Most memory
1449 ** allocators round up memory allocations at least to the next multiple
1450 ** of 8. Some allocators round up to a larger multiple or to a power of 2.
1451 ** Every memory allocation request coming in through [sqlite3_malloc()]
1452 ** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0,
1453 ** that causes the corresponding memory allocation to fail.
1455 ** The xInit method initializes the memory allocator. For example,
1456 ** it might allocate any require mutexes or initialize internal data
1457 ** structures. The xShutdown method is invoked (indirectly) by
1458 ** [sqlite3_shutdown()] and should deallocate any resources acquired
1459 ** by xInit. The pAppData pointer is used as the only parameter to
1460 ** xInit and xShutdown.
1462 ** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes
1463 ** the xInit method, so the xInit method need not be threadsafe. The
1464 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
1465 ** not need to be threadsafe either. For all other methods, SQLite
1466 ** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
1467 ** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
1468 ** it is by default) and so the methods are automatically serialized.
1469 ** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
1470 ** methods must be threadsafe or else make their own arrangements for
1473 ** SQLite will never invoke xInit() more than once without an intervening
1474 ** call to xShutdown().
1476 typedef struct sqlite3_mem_methods sqlite3_mem_methods;
1477 struct sqlite3_mem_methods {
1478 void *(*xMalloc)(int); /* Memory allocation function */
1479 void (*xFree)(void*); /* Free a prior allocation */
1480 void *(*xRealloc)(void*,int); /* Resize an allocation */
1481 int (*xSize)(void*); /* Return the size of an allocation */
1482 int (*xRoundup)(int); /* Round up request size to allocation size */
1483 int (*xInit)(void*); /* Initialize the memory allocator */
1484 void (*xShutdown)(void*); /* Deinitialize the memory allocator */
1485 void *pAppData; /* Argument to xInit() and xShutdown() */
1489 ** CAPI3REF: Configuration Options
1490 ** KEYWORDS: {configuration option}
1492 ** These constants are the available integer configuration options that
1493 ** can be passed as the first argument to the [sqlite3_config()] interface.
1495 ** New configuration options may be added in future releases of SQLite.
1496 ** Existing configuration options might be discontinued. Applications
1497 ** should check the return code from [sqlite3_config()] to make sure that
1498 ** the call worked. The [sqlite3_config()] interface will return a
1499 ** non-zero [error code] if a discontinued or unsupported configuration option
1503 ** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
1504 ** <dd>There are no arguments to this option. ^This option sets the
1505 ** [threading mode] to Single-thread. In other words, it disables
1506 ** all mutexing and puts SQLite into a mode where it can only be used
1507 ** by a single thread. ^If SQLite is compiled with
1508 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1509 ** it is not possible to change the [threading mode] from its default
1510 ** value of Single-thread and so [sqlite3_config()] will return
1511 ** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
1512 ** configuration option.</dd>
1514 ** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt>
1515 ** <dd>There are no arguments to this option. ^This option sets the
1516 ** [threading mode] to Multi-thread. In other words, it disables
1517 ** mutexing on [database connection] and [prepared statement] objects.
1518 ** The application is responsible for serializing access to
1519 ** [database connections] and [prepared statements]. But other mutexes
1520 ** are enabled so that SQLite will be safe to use in a multi-threaded
1521 ** environment as long as no two threads attempt to use the same
1522 ** [database connection] at the same time. ^If SQLite is compiled with
1523 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1524 ** it is not possible to set the Multi-thread [threading mode] and
1525 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1526 ** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
1528 ** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt>
1529 ** <dd>There are no arguments to this option. ^This option sets the
1530 ** [threading mode] to Serialized. In other words, this option enables
1531 ** all mutexes including the recursive
1532 ** mutexes on [database connection] and [prepared statement] objects.
1533 ** In this mode (which is the default when SQLite is compiled with
1534 ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
1535 ** to [database connections] and [prepared statements] so that the
1536 ** application is free to use the same [database connection] or the
1537 ** same [prepared statement] in different threads at the same time.
1538 ** ^If SQLite is compiled with
1539 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1540 ** it is not possible to set the Serialized [threading mode] and
1541 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1542 ** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
1544 ** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt>
1545 ** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is
1546 ** a pointer to an instance of the [sqlite3_mem_methods] structure.
1547 ** The argument specifies
1548 ** alternative low-level memory allocation routines to be used in place of
1549 ** the memory allocation routines built into SQLite.)^ ^SQLite makes
1550 ** its own private copy of the content of the [sqlite3_mem_methods] structure
1551 ** before the [sqlite3_config()] call returns.</dd>
1553 ** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt>
1554 ** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which
1555 ** is a pointer to an instance of the [sqlite3_mem_methods] structure.
1556 ** The [sqlite3_mem_methods]
1557 ** structure is filled with the currently defined memory allocation routines.)^
1558 ** This option can be used to overload the default memory allocation
1559 ** routines with a wrapper that simulations memory allocation failure or
1560 ** tracks memory usage, for example. </dd>
1562 ** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt>
1563 ** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int,
1564 ** interpreted as a boolean, which enables or disables the collection of
1565 ** memory allocation statistics. ^(When memory allocation statistics are
1566 ** disabled, the following SQLite interfaces become non-operational:
1568 ** <li> [sqlite3_memory_used()]
1569 ** <li> [sqlite3_memory_highwater()]
1570 ** <li> [sqlite3_soft_heap_limit64()]
1571 ** <li> [sqlite3_status64()]
1573 ** ^Memory allocation statistics are enabled by default unless SQLite is
1574 ** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
1575 ** allocation statistics are disabled by default.
1578 ** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt>
1579 ** <dd> ^The SQLITE_CONFIG_SCRATCH option specifies a static memory buffer
1580 ** that SQLite can use for scratch memory. ^(There are three arguments
1581 ** to SQLITE_CONFIG_SCRATCH: A pointer an 8-byte
1582 ** aligned memory buffer from which the scratch allocations will be
1583 ** drawn, the size of each scratch allocation (sz),
1584 ** and the maximum number of scratch allocations (N).)^
1585 ** The first argument must be a pointer to an 8-byte aligned buffer
1586 ** of at least sz*N bytes of memory.
1587 ** ^SQLite will not use more than one scratch buffers per thread.
1588 ** ^SQLite will never request a scratch buffer that is more than 6
1589 ** times the database page size.
1590 ** ^If SQLite needs needs additional
1591 ** scratch memory beyond what is provided by this configuration option, then
1592 ** [sqlite3_malloc()] will be used to obtain the memory needed.<p>
1593 ** ^When the application provides any amount of scratch memory using
1594 ** SQLITE_CONFIG_SCRATCH, SQLite avoids unnecessary large
1595 ** [sqlite3_malloc|heap allocations].
1596 ** This can help [Robson proof|prevent memory allocation failures] due to heap
1597 ** fragmentation in low-memory embedded systems.
1600 ** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>
1601 ** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a static memory buffer
1602 ** that SQLite can use for the database page cache with the default page
1603 ** cache implementation.
1604 ** This configuration should not be used if an application-define page
1605 ** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2]
1606 ** configuration option.
1607 ** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to
1609 ** memory, the size of each page buffer (sz), and the number of pages (N).
1610 ** The sz argument should be the size of the largest database page
1611 ** (a power of two between 512 and 65536) plus some extra bytes for each
1612 ** page header. ^The number of extra bytes needed by the page header
1613 ** can be determined using the [SQLITE_CONFIG_PCACHE_HDRSZ] option
1614 ** to [sqlite3_config()].
1615 ** ^It is harmless, apart from the wasted memory,
1616 ** for the sz parameter to be larger than necessary. The first
1617 ** argument should pointer to an 8-byte aligned block of memory that
1618 ** is at least sz*N bytes of memory, otherwise subsequent behavior is
1620 ** ^SQLite will use the memory provided by the first argument to satisfy its
1621 ** memory needs for the first N pages that it adds to cache. ^If additional
1622 ** page cache memory is needed beyond what is provided by this option, then
1623 ** SQLite goes to [sqlite3_malloc()] for the additional storage space.</dd>
1625 ** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt>
1626 ** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer
1627 ** that SQLite will use for all of its dynamic memory allocation needs
1628 ** beyond those provided for by [SQLITE_CONFIG_SCRATCH] and
1629 ** [SQLITE_CONFIG_PAGECACHE].
1630 ** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled
1631 ** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns
1632 ** [SQLITE_ERROR] if invoked otherwise.
1633 ** ^There are three arguments to SQLITE_CONFIG_HEAP:
1634 ** An 8-byte aligned pointer to the memory,
1635 ** the number of bytes in the memory buffer, and the minimum allocation size.
1636 ** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
1637 ** to using its default memory allocator (the system malloc() implementation),
1638 ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the
1639 ** memory pointer is not NULL then the alternative memory
1640 ** allocator is engaged to handle all of SQLites memory allocation needs.
1641 ** The first pointer (the memory pointer) must be aligned to an 8-byte
1642 ** boundary or subsequent behavior of SQLite will be undefined.
1643 ** The minimum allocation size is capped at 2**12. Reasonable values
1644 ** for the minimum allocation size are 2**5 through 2**8.</dd>
1646 ** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt>
1647 ** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a
1648 ** pointer to an instance of the [sqlite3_mutex_methods] structure.
1649 ** The argument specifies alternative low-level mutex routines to be used
1650 ** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of
1651 ** the content of the [sqlite3_mutex_methods] structure before the call to
1652 ** [sqlite3_config()] returns. ^If SQLite is compiled with
1653 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1654 ** the entire mutexing subsystem is omitted from the build and hence calls to
1655 ** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
1656 ** return [SQLITE_ERROR].</dd>
1658 ** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt>
1659 ** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which
1660 ** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The
1661 ** [sqlite3_mutex_methods]
1662 ** structure is filled with the currently defined mutex routines.)^
1663 ** This option can be used to overload the default mutex allocation
1664 ** routines with a wrapper used to track mutex usage for performance
1665 ** profiling or testing, for example. ^If SQLite is compiled with
1666 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1667 ** the entire mutexing subsystem is omitted from the build and hence calls to
1668 ** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
1669 ** return [SQLITE_ERROR].</dd>
1671 ** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt>
1672 ** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine
1673 ** the default size of lookaside memory on each [database connection].
1674 ** The first argument is the
1675 ** size of each lookaside buffer slot and the second is the number of
1676 ** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE
1677 ** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
1678 ** option to [sqlite3_db_config()] can be used to change the lookaside
1679 ** configuration on individual connections.)^ </dd>
1681 ** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt>
1682 ** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is
1683 ** a pointer to an [sqlite3_pcache_methods2] object. This object specifies
1684 ** the interface to a custom page cache implementation.)^
1685 ** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd>
1687 ** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt>
1688 ** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which
1689 ** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of
1690 ** the current page cache implementation into that object.)^ </dd>
1692 ** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>
1693 ** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite
1694 ** global [error log].
1695 ** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
1696 ** function with a call signature of void(*)(void*,int,const char*),
1697 ** and a pointer to void. ^If the function pointer is not NULL, it is
1698 ** invoked by [sqlite3_log()] to process each logging event. ^If the
1699 ** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
1700 ** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
1701 ** passed through as the first parameter to the application-defined logger
1702 ** function whenever that function is invoked. ^The second parameter to
1703 ** the logger function is a copy of the first parameter to the corresponding
1704 ** [sqlite3_log()] call and is intended to be a [result code] or an
1705 ** [extended result code]. ^The third parameter passed to the logger is
1706 ** log message after formatting via [sqlite3_snprintf()].
1707 ** The SQLite logging interface is not reentrant; the logger function
1708 ** supplied by the application must not invoke any SQLite interface.
1709 ** In a multi-threaded application, the application-defined logger
1710 ** function must be threadsafe. </dd>
1712 ** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI
1713 ** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int.
1714 ** If non-zero, then URI handling is globally enabled. If the parameter is zero,
1715 ** then URI handling is globally disabled.)^ ^If URI handling is globally
1716 ** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()],
1717 ** [sqlite3_open16()] or
1718 ** specified as part of [ATTACH] commands are interpreted as URIs, regardless
1719 ** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
1720 ** connection is opened. ^If it is globally disabled, filenames are
1721 ** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
1722 ** database connection is opened. ^(By default, URI handling is globally
1723 ** disabled. The default value may be changed by compiling with the
1724 ** [SQLITE_USE_URI] symbol defined.)^
1726 ** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN
1727 ** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer
1728 ** argument which is interpreted as a boolean in order to enable or disable
1729 ** the use of covering indices for full table scans in the query optimizer.
1730 ** ^The default setting is determined
1731 ** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on"
1732 ** if that compile-time option is omitted.
1733 ** The ability to disable the use of covering indices for full table scans
1734 ** is because some incorrectly coded legacy applications might malfunction
1735 ** when the optimization is enabled. Providing the ability to
1736 ** disable the optimization allows the older, buggy application code to work
1737 ** without change even with newer versions of SQLite.
1739 ** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]]
1740 ** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE
1741 ** <dd> These options are obsolete and should not be used by new code.
1742 ** They are retained for backwards compatibility but are now no-ops.
1745 ** [[SQLITE_CONFIG_SQLLOG]]
1746 ** <dt>SQLITE_CONFIG_SQLLOG
1747 ** <dd>This option is only available if sqlite is compiled with the
1748 ** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should
1749 ** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int).
1750 ** The second should be of type (void*). The callback is invoked by the library
1751 ** in three separate circumstances, identified by the value passed as the
1752 ** fourth parameter. If the fourth parameter is 0, then the database connection
1753 ** passed as the second argument has just been opened. The third argument
1754 ** points to a buffer containing the name of the main database file. If the
1755 ** fourth parameter is 1, then the SQL statement that the third parameter
1756 ** points to has just been executed. Or, if the fourth parameter is 2, then
1757 ** the connection being passed as the second parameter is being closed. The
1758 ** third parameter is passed NULL In this case. An example of using this
1759 ** configuration option can be seen in the "test_sqllog.c" source file in
1760 ** the canonical SQLite source tree.</dd>
1762 ** [[SQLITE_CONFIG_MMAP_SIZE]]
1763 ** <dt>SQLITE_CONFIG_MMAP_SIZE
1764 ** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values
1765 ** that are the default mmap size limit (the default setting for
1766 ** [PRAGMA mmap_size]) and the maximum allowed mmap size limit.
1767 ** ^The default setting can be overridden by each database connection using
1768 ** either the [PRAGMA mmap_size] command, or by using the
1769 ** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size
1770 ** will be silently truncated if necessary so that it does not exceed the
1771 ** compile-time maximum mmap size set by the
1772 ** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^
1773 ** ^If either argument to this option is negative, then that argument is
1774 ** changed to its compile-time default.
1776 ** [[SQLITE_CONFIG_WIN32_HEAPSIZE]]
1777 ** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE
1778 ** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is
1779 ** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro
1780 ** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value
1781 ** that specifies the maximum size of the created heap.
1783 ** [[SQLITE_CONFIG_PCACHE_HDRSZ]]
1784 ** <dt>SQLITE_CONFIG_PCACHE_HDRSZ
1785 ** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which
1786 ** is a pointer to an integer and writes into that integer the number of extra
1787 ** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE].
1788 ** The amount of extra space required can change depending on the compiler,
1789 ** target platform, and SQLite version.
1791 ** [[SQLITE_CONFIG_PMASZ]]
1792 ** <dt>SQLITE_CONFIG_PMASZ
1793 ** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which
1794 ** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded
1795 ** sorter to that integer. The default minimum PMA Size is set by the
1796 ** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched
1797 ** to help with sort operations when multithreaded sorting
1798 ** is enabled (using the [PRAGMA threads] command) and the amount of content
1799 ** to be sorted exceeds the page size times the minimum of the
1800 ** [PRAGMA cache_size] setting and this value.
1803 #define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */
1804 #define SQLITE_CONFIG_MULTITHREAD 2 /* nil */
1805 #define SQLITE_CONFIG_SERIALIZED 3 /* nil */
1806 #define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */
1807 #define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */
1808 #define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */
1809 #define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */
1810 #define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */
1811 #define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */
1812 #define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */
1813 #define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */
1814 /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */
1815 #define SQLITE_CONFIG_LOOKASIDE 13 /* int int */
1816 #define SQLITE_CONFIG_PCACHE 14 /* no-op */
1817 #define SQLITE_CONFIG_GETPCACHE 15 /* no-op */
1818 #define SQLITE_CONFIG_LOG 16 /* xFunc, void* */
1819 #define SQLITE_CONFIG_URI 17 /* int */
1820 #define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */
1821 #define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */
1822 #define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */
1823 #define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */
1824 #define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */
1825 #define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */
1826 #define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */
1827 #define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */
1830 ** CAPI3REF: Database Connection Configuration Options
1832 ** These constants are the available integer configuration options that
1833 ** can be passed as the second argument to the [sqlite3_db_config()] interface.
1835 ** New configuration options may be added in future releases of SQLite.
1836 ** Existing configuration options might be discontinued. Applications
1837 ** should check the return code from [sqlite3_db_config()] to make sure that
1838 ** the call worked. ^The [sqlite3_db_config()] interface will return a
1839 ** non-zero [error code] if a discontinued or unsupported configuration option
1843 ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
1844 ** <dd> ^This option takes three additional arguments that determine the
1845 ** [lookaside memory allocator] configuration for the [database connection].
1846 ** ^The first argument (the third parameter to [sqlite3_db_config()] is a
1847 ** pointer to a memory buffer to use for lookaside memory.
1848 ** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
1849 ** may be NULL in which case SQLite will allocate the
1850 ** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
1851 ** size of each lookaside buffer slot. ^The third argument is the number of
1852 ** slots. The size of the buffer in the first argument must be greater than
1853 ** or equal to the product of the second and third arguments. The buffer
1854 ** must be aligned to an 8-byte boundary. ^If the second argument to
1855 ** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
1856 ** rounded down to the next smaller multiple of 8. ^(The lookaside memory
1857 ** configuration for a database connection can only be changed when that
1858 ** connection is not currently using lookaside memory, or in other words
1859 ** when the "current value" returned by
1860 ** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero.
1861 ** Any attempt to change the lookaside memory configuration when lookaside
1862 ** memory is in use leaves the configuration unchanged and returns
1863 ** [SQLITE_BUSY].)^</dd>
1865 ** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
1866 ** <dd> ^This option is used to enable or disable the enforcement of
1867 ** [foreign key constraints]. There should be two additional arguments.
1868 ** The first argument is an integer which is 0 to disable FK enforcement,
1869 ** positive to enable FK enforcement or negative to leave FK enforcement
1870 ** unchanged. The second parameter is a pointer to an integer into which
1871 ** is written 0 or 1 to indicate whether FK enforcement is off or on
1872 ** following this call. The second parameter may be a NULL pointer, in
1873 ** which case the FK enforcement setting is not reported back. </dd>
1875 ** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
1876 ** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
1877 ** There should be two additional arguments.
1878 ** The first argument is an integer which is 0 to disable triggers,
1879 ** positive to enable triggers or negative to leave the setting unchanged.
1880 ** The second parameter is a pointer to an integer into which
1881 ** is written 0 or 1 to indicate whether triggers are disabled or enabled
1882 ** following this call. The second parameter may be a NULL pointer, in
1883 ** which case the trigger setting is not reported back. </dd>
1887 #define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */
1888 #define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */
1889 #define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */
1893 ** CAPI3REF: Enable Or Disable Extended Result Codes
1896 ** ^The sqlite3_extended_result_codes() routine enables or disables the
1897 ** [extended result codes] feature of SQLite. ^The extended result
1898 ** codes are disabled by default for historical compatibility.
1900 SQLITE_API int SQLITE_STDCALL sqlite3_extended_result_codes(sqlite3*, int onoff);
1903 ** CAPI3REF: Last Insert Rowid
1906 ** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables)
1907 ** has a unique 64-bit signed
1908 ** integer key called the [ROWID | "rowid"]. ^The rowid is always available
1909 ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
1910 ** names are not also used by explicitly declared columns. ^If
1911 ** the table has a column of type [INTEGER PRIMARY KEY] then that column
1912 ** is another alias for the rowid.
1914 ** ^The sqlite3_last_insert_rowid(D) interface returns the [rowid] of the
1915 ** most recent successful [INSERT] into a rowid table or [virtual table]
1916 ** on database connection D.
1917 ** ^Inserts into [WITHOUT ROWID] tables are not recorded.
1918 ** ^If no successful [INSERT]s into rowid tables
1919 ** have ever occurred on the database connection D,
1920 ** then sqlite3_last_insert_rowid(D) returns zero.
1922 ** ^(If an [INSERT] occurs within a trigger or within a [virtual table]
1923 ** method, then this routine will return the [rowid] of the inserted
1924 ** row as long as the trigger or virtual table method is running.
1925 ** But once the trigger or virtual table method ends, the value returned
1926 ** by this routine reverts to what it was before the trigger or virtual
1927 ** table method began.)^
1929 ** ^An [INSERT] that fails due to a constraint violation is not a
1930 ** successful [INSERT] and does not change the value returned by this
1931 ** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
1932 ** and INSERT OR ABORT make no changes to the return value of this
1933 ** routine when their insertion fails. ^(When INSERT OR REPLACE
1934 ** encounters a constraint violation, it does not fail. The
1935 ** INSERT continues to completion after deleting rows that caused
1936 ** the constraint problem so INSERT OR REPLACE will always change
1937 ** the return value of this interface.)^
1939 ** ^For the purposes of this routine, an [INSERT] is considered to
1940 ** be successful even if it is subsequently rolled back.
1942 ** This function is accessible to SQL statements via the
1943 ** [last_insert_rowid() SQL function].
1945 ** If a separate thread performs a new [INSERT] on the same
1946 ** database connection while the [sqlite3_last_insert_rowid()]
1947 ** function is running and thus changes the last insert [rowid],
1948 ** then the value returned by [sqlite3_last_insert_rowid()] is
1949 ** unpredictable and might not equal either the old or the new
1950 ** last insert [rowid].
1952 SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_last_insert_rowid(sqlite3*);
1955 ** CAPI3REF: Count The Number Of Rows Modified
1958 ** ^This function returns the number of rows modified, inserted or
1959 ** deleted by the most recently completed INSERT, UPDATE or DELETE
1960 ** statement on the database connection specified by the only parameter.
1961 ** ^Executing any other type of SQL statement does not modify the value
1962 ** returned by this function.
1964 ** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are
1965 ** considered - auxiliary changes caused by [CREATE TRIGGER | triggers],
1966 ** [foreign key actions] or [REPLACE] constraint resolution are not counted.
1968 ** Changes to a view that are intercepted by
1969 ** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value
1970 ** returned by sqlite3_changes() immediately after an INSERT, UPDATE or
1971 ** DELETE statement run on a view is always zero. Only changes made to real
1972 ** tables are counted.
1974 ** Things are more complicated if the sqlite3_changes() function is
1975 ** executed while a trigger program is running. This may happen if the
1976 ** program uses the [changes() SQL function], or if some other callback
1977 ** function invokes sqlite3_changes() directly. Essentially:
1980 ** <li> ^(Before entering a trigger program the value returned by
1981 ** sqlite3_changes() function is saved. After the trigger program
1982 ** has finished, the original value is restored.)^
1984 ** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE
1985 ** statement sets the value returned by sqlite3_changes()
1986 ** upon completion as normal. Of course, this value will not include
1987 ** any changes performed by sub-triggers, as the sqlite3_changes()
1988 ** value will be saved and restored after each sub-trigger has run.)^
1991 ** ^This means that if the changes() SQL function (or similar) is used
1992 ** by the first INSERT, UPDATE or DELETE statement within a trigger, it
1993 ** returns the value as set when the calling statement began executing.
1994 ** ^If it is used by the second or subsequent such statement within a trigger
1995 ** program, the value returned reflects the number of rows modified by the
1996 ** previous INSERT, UPDATE or DELETE statement within the same trigger.
1998 ** See also the [sqlite3_total_changes()] interface, the
1999 ** [count_changes pragma], and the [changes() SQL function].
2001 ** If a separate thread makes changes on the same database connection
2002 ** while [sqlite3_changes()] is running then the value returned
2003 ** is unpredictable and not meaningful.
2005 SQLITE_API int SQLITE_STDCALL sqlite3_changes(sqlite3*);
2008 ** CAPI3REF: Total Number Of Rows Modified
2011 ** ^This function returns the total number of rows inserted, modified or
2012 ** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed
2013 ** since the database connection was opened, including those executed as
2014 ** part of trigger programs. ^Executing any other type of SQL statement
2015 ** does not affect the value returned by sqlite3_total_changes().
2017 ** ^Changes made as part of [foreign key actions] are included in the
2018 ** count, but those made as part of REPLACE constraint resolution are
2019 ** not. ^Changes to a view that are intercepted by INSTEAD OF triggers
2022 ** See also the [sqlite3_changes()] interface, the
2023 ** [count_changes pragma], and the [total_changes() SQL function].
2025 ** If a separate thread makes changes on the same database connection
2026 ** while [sqlite3_total_changes()] is running then the value
2027 ** returned is unpredictable and not meaningful.
2029 SQLITE_API int SQLITE_STDCALL sqlite3_total_changes(sqlite3*);
2032 ** CAPI3REF: Interrupt A Long-Running Query
2035 ** ^This function causes any pending database operation to abort and
2036 ** return at its earliest opportunity. This routine is typically
2037 ** called in response to a user action such as pressing "Cancel"
2038 ** or Ctrl-C where the user wants a long query operation to halt
2041 ** ^It is safe to call this routine from a thread different from the
2042 ** thread that is currently running the database operation. But it
2043 ** is not safe to call this routine with a [database connection] that
2044 ** is closed or might close before sqlite3_interrupt() returns.
2046 ** ^If an SQL operation is very nearly finished at the time when
2047 ** sqlite3_interrupt() is called, then it might not have an opportunity
2048 ** to be interrupted and might continue to completion.
2050 ** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
2051 ** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
2052 ** that is inside an explicit transaction, then the entire transaction
2053 ** will be rolled back automatically.
2055 ** ^The sqlite3_interrupt(D) call is in effect until all currently running
2056 ** SQL statements on [database connection] D complete. ^Any new SQL statements
2057 ** that are started after the sqlite3_interrupt() call and before the
2058 ** running statements reaches zero are interrupted as if they had been
2059 ** running prior to the sqlite3_interrupt() call. ^New SQL statements
2060 ** that are started after the running statement count reaches zero are
2061 ** not effected by the sqlite3_interrupt().
2062 ** ^A call to sqlite3_interrupt(D) that occurs when there are no running
2063 ** SQL statements is a no-op and has no effect on SQL statements
2064 ** that are started after the sqlite3_interrupt() call returns.
2066 ** If the database connection closes while [sqlite3_interrupt()]
2067 ** is running then bad things will likely happen.
2069 SQLITE_API void SQLITE_STDCALL sqlite3_interrupt(sqlite3*);
2072 ** CAPI3REF: Determine If An SQL Statement Is Complete
2074 ** These routines are useful during command-line input to determine if the
2075 ** currently entered text seems to form a complete SQL statement or
2076 ** if additional input is needed before sending the text into
2077 ** SQLite for parsing. ^These routines return 1 if the input string
2078 ** appears to be a complete SQL statement. ^A statement is judged to be
2079 ** complete if it ends with a semicolon token and is not a prefix of a
2080 ** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within
2081 ** string literals or quoted identifier names or comments are not
2082 ** independent tokens (they are part of the token in which they are
2083 ** embedded) and thus do not count as a statement terminator. ^Whitespace
2084 ** and comments that follow the final semicolon are ignored.
2086 ** ^These routines return 0 if the statement is incomplete. ^If a
2087 ** memory allocation fails, then SQLITE_NOMEM is returned.
2089 ** ^These routines do not parse the SQL statements thus
2090 ** will not detect syntactically incorrect SQL.
2092 ** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior
2093 ** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
2094 ** automatically by sqlite3_complete16(). If that initialization fails,
2095 ** then the return value from sqlite3_complete16() will be non-zero
2096 ** regardless of whether or not the input SQL is complete.)^
2098 ** The input to [sqlite3_complete()] must be a zero-terminated
2101 ** The input to [sqlite3_complete16()] must be a zero-terminated
2102 ** UTF-16 string in native byte order.
2104 SQLITE_API int SQLITE_STDCALL sqlite3_complete(const char *sql);
2105 SQLITE_API int SQLITE_STDCALL sqlite3_complete16(const void *sql);
2108 ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
2109 ** KEYWORDS: {busy-handler callback} {busy handler}
2112 ** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X
2113 ** that might be invoked with argument P whenever
2114 ** an attempt is made to access a database table associated with
2115 ** [database connection] D when another thread
2116 ** or process has the table locked.
2117 ** The sqlite3_busy_handler() interface is used to implement
2118 ** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout].
2120 ** ^If the busy callback is NULL, then [SQLITE_BUSY]
2121 ** is returned immediately upon encountering the lock. ^If the busy callback
2122 ** is not NULL, then the callback might be invoked with two arguments.
2124 ** ^The first argument to the busy handler is a copy of the void* pointer which
2125 ** is the third argument to sqlite3_busy_handler(). ^The second argument to
2126 ** the busy handler callback is the number of times that the busy handler has
2127 ** been invoked previously for the same locking event. ^If the
2128 ** busy callback returns 0, then no additional attempts are made to
2129 ** access the database and [SQLITE_BUSY] is returned
2130 ** to the application.
2131 ** ^If the callback returns non-zero, then another attempt
2132 ** is made to access the database and the cycle repeats.
2134 ** The presence of a busy handler does not guarantee that it will be invoked
2135 ** when there is lock contention. ^If SQLite determines that invoking the busy
2136 ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
2137 ** to the application instead of invoking the
2139 ** Consider a scenario where one process is holding a read lock that
2140 ** it is trying to promote to a reserved lock and
2141 ** a second process is holding a reserved lock that it is trying
2142 ** to promote to an exclusive lock. The first process cannot proceed
2143 ** because it is blocked by the second and the second process cannot
2144 ** proceed because it is blocked by the first. If both processes
2145 ** invoke the busy handlers, neither will make any progress. Therefore,
2146 ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
2147 ** will induce the first process to release its read lock and allow
2148 ** the second process to proceed.
2150 ** ^The default busy callback is NULL.
2152 ** ^(There can only be a single busy handler defined for each
2153 ** [database connection]. Setting a new busy handler clears any
2154 ** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()]
2155 ** or evaluating [PRAGMA busy_timeout=N] will change the
2156 ** busy handler and thus clear any previously set busy handler.
2158 ** The busy callback should not take any actions which modify the
2159 ** database connection that invoked the busy handler. In other words,
2160 ** the busy handler is not reentrant. Any such actions
2161 ** result in undefined behavior.
2163 ** A busy handler must not close the database connection
2164 ** or [prepared statement] that invoked the busy handler.
2166 SQLITE_API int SQLITE_STDCALL sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*);
2169 ** CAPI3REF: Set A Busy Timeout
2172 ** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
2173 ** for a specified amount of time when a table is locked. ^The handler
2174 ** will sleep multiple times until at least "ms" milliseconds of sleeping
2175 ** have accumulated. ^After at least "ms" milliseconds of sleeping,
2176 ** the handler returns 0 which causes [sqlite3_step()] to return
2179 ** ^Calling this routine with an argument less than or equal to zero
2180 ** turns off all busy handlers.
2182 ** ^(There can only be a single busy handler for a particular
2183 ** [database connection] at any given moment. If another busy handler
2184 ** was defined (using [sqlite3_busy_handler()]) prior to calling
2185 ** this routine, that other busy handler is cleared.)^
2187 ** See also: [PRAGMA busy_timeout]
2189 SQLITE_API int SQLITE_STDCALL sqlite3_busy_timeout(sqlite3*, int ms);
2192 ** CAPI3REF: Convenience Routines For Running Queries
2195 ** This is a legacy interface that is preserved for backwards compatibility.
2196 ** Use of this interface is not recommended.
2198 ** Definition: A <b>result table</b> is memory data structure created by the
2199 ** [sqlite3_get_table()] interface. A result table records the
2200 ** complete query results from one or more queries.
2202 ** The table conceptually has a number of rows and columns. But
2203 ** these numbers are not part of the result table itself. These
2204 ** numbers are obtained separately. Let N be the number of rows
2205 ** and M be the number of columns.
2207 ** A result table is an array of pointers to zero-terminated UTF-8 strings.
2208 ** There are (N+1)*M elements in the array. The first M pointers point
2209 ** to zero-terminated strings that contain the names of the columns.
2210 ** The remaining entries all point to query results. NULL values result
2211 ** in NULL pointers. All other values are in their UTF-8 zero-terminated
2212 ** string representation as returned by [sqlite3_column_text()].
2214 ** A result table might consist of one or more memory allocations.
2215 ** It is not safe to pass a result table directly to [sqlite3_free()].
2216 ** A result table should be deallocated using [sqlite3_free_table()].
2218 ** ^(As an example of the result table format, suppose a query result
2221 ** <blockquote><pre>
2223 ** -----------------------
2227 ** </pre></blockquote>
2229 ** There are two column (M==2) and three rows (N==3). Thus the
2230 ** result table has 8 entries. Suppose the result table is stored
2231 ** in an array names azResult. Then azResult holds this content:
2233 ** <blockquote><pre>
2234 ** azResult[0] = "Name";
2235 ** azResult[1] = "Age";
2236 ** azResult[2] = "Alice";
2237 ** azResult[3] = "43";
2238 ** azResult[4] = "Bob";
2239 ** azResult[5] = "28";
2240 ** azResult[6] = "Cindy";
2241 ** azResult[7] = "21";
2242 ** </pre></blockquote>)^
2244 ** ^The sqlite3_get_table() function evaluates one or more
2245 ** semicolon-separated SQL statements in the zero-terminated UTF-8
2246 ** string of its 2nd parameter and returns a result table to the
2247 ** pointer given in its 3rd parameter.
2249 ** After the application has finished with the result from sqlite3_get_table(),
2250 ** it must pass the result table pointer to sqlite3_free_table() in order to
2251 ** release the memory that was malloced. Because of the way the
2252 ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
2253 ** function must not try to call [sqlite3_free()] directly. Only
2254 ** [sqlite3_free_table()] is able to release the memory properly and safely.
2256 ** The sqlite3_get_table() interface is implemented as a wrapper around
2257 ** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access
2258 ** to any internal data structures of SQLite. It uses only the public
2259 ** interface defined here. As a consequence, errors that occur in the
2260 ** wrapper layer outside of the internal [sqlite3_exec()] call are not
2261 ** reflected in subsequent calls to [sqlite3_errcode()] or
2262 ** [sqlite3_errmsg()].
2264 SQLITE_API int SQLITE_STDCALL sqlite3_get_table(
2265 sqlite3 *db, /* An open database */
2266 const char *zSql, /* SQL to be evaluated */
2267 char ***pazResult, /* Results of the query */
2268 int *pnRow, /* Number of result rows written here */
2269 int *pnColumn, /* Number of result columns written here */
2270 char **pzErrmsg /* Error msg written here */
2272 SQLITE_API void SQLITE_STDCALL sqlite3_free_table(char **result);
2275 ** CAPI3REF: Formatted String Printing Functions
2277 ** These routines are work-alikes of the "printf()" family of functions
2278 ** from the standard C library.
2279 ** These routines understand most of the common K&R formatting options,
2280 ** plus some additional non-standard formats, detailed below.
2281 ** Note that some of the more obscure formatting options from recent
2282 ** C-library standards are omitted from this implementation.
2284 ** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
2285 ** results into memory obtained from [sqlite3_malloc()].
2286 ** The strings returned by these two routines should be
2287 ** released by [sqlite3_free()]. ^Both routines return a
2288 ** NULL pointer if [sqlite3_malloc()] is unable to allocate enough
2289 ** memory to hold the resulting string.
2291 ** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
2292 ** the standard C library. The result is written into the
2293 ** buffer supplied as the second parameter whose size is given by
2294 ** the first parameter. Note that the order of the
2295 ** first two parameters is reversed from snprintf().)^ This is an
2296 ** historical accident that cannot be fixed without breaking
2297 ** backwards compatibility. ^(Note also that sqlite3_snprintf()
2298 ** returns a pointer to its buffer instead of the number of
2299 ** characters actually written into the buffer.)^ We admit that
2300 ** the number of characters written would be a more useful return
2301 ** value but we cannot change the implementation of sqlite3_snprintf()
2302 ** now without breaking compatibility.
2304 ** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
2305 ** guarantees that the buffer is always zero-terminated. ^The first
2306 ** parameter "n" is the total size of the buffer, including space for
2307 ** the zero terminator. So the longest string that can be completely
2308 ** written will be n-1 characters.
2310 ** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
2312 ** These routines all implement some additional formatting
2313 ** options that are useful for constructing SQL statements.
2314 ** All of the usual printf() formatting options apply. In addition, there
2315 ** is are "%q", "%Q", "%w" and "%z" options.
2317 ** ^(The %q option works like %s in that it substitutes a nul-terminated
2318 ** string from the argument list. But %q also doubles every '\'' character.
2319 ** %q is designed for use inside a string literal.)^ By doubling each '\''
2320 ** character it escapes that character and allows it to be inserted into
2323 ** For example, assume the string variable zText contains text as follows:
2325 ** <blockquote><pre>
2326 ** char *zText = "It's a happy day!";
2327 ** </pre></blockquote>
2329 ** One can use this text in an SQL statement as follows:
2331 ** <blockquote><pre>
2332 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText);
2333 ** sqlite3_exec(db, zSQL, 0, 0, 0);
2334 ** sqlite3_free(zSQL);
2335 ** </pre></blockquote>
2337 ** Because the %q format string is used, the '\'' character in zText
2338 ** is escaped and the SQL generated is as follows:
2340 ** <blockquote><pre>
2341 ** INSERT INTO table1 VALUES('It''s a happy day!')
2342 ** </pre></blockquote>
2344 ** This is correct. Had we used %s instead of %q, the generated SQL
2345 ** would have looked like this:
2347 ** <blockquote><pre>
2348 ** INSERT INTO table1 VALUES('It's a happy day!');
2349 ** </pre></blockquote>
2351 ** This second example is an SQL syntax error. As a general rule you should
2352 ** always use %q instead of %s when inserting text into a string literal.
2354 ** ^(The %Q option works like %q except it also adds single quotes around
2355 ** the outside of the total string. Additionally, if the parameter in the
2356 ** argument list is a NULL pointer, %Q substitutes the text "NULL" (without
2357 ** single quotes).)^ So, for example, one could say:
2359 ** <blockquote><pre>
2360 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText);
2361 ** sqlite3_exec(db, zSQL, 0, 0, 0);
2362 ** sqlite3_free(zSQL);
2363 ** </pre></blockquote>
2365 ** The code above will render a correct SQL statement in the zSQL
2366 ** variable even if the zText variable is a NULL pointer.
2368 ** ^(The "%w" formatting option is like "%q" except that it expects to
2369 ** be contained within double-quotes instead of single quotes, and it
2370 ** escapes the double-quote character instead of the single-quote
2371 ** character.)^ The "%w" formatting option is intended for safely inserting
2372 ** table and column names into a constructed SQL statement.
2374 ** ^(The "%z" formatting option works like "%s" but with the
2375 ** addition that after the string has been read and copied into
2376 ** the result, [sqlite3_free()] is called on the input string.)^
2378 SQLITE_API char *SQLITE_CDECL sqlite3_mprintf(const char*,...);
2379 SQLITE_API char *SQLITE_STDCALL sqlite3_vmprintf(const char*, va_list);
2380 SQLITE_API char *SQLITE_CDECL sqlite3_snprintf(int,char*,const char*, ...);
2381 SQLITE_API char *SQLITE_STDCALL sqlite3_vsnprintf(int,char*,const char*, va_list);
2384 ** CAPI3REF: Memory Allocation Subsystem
2386 ** The SQLite core uses these three routines for all of its own
2387 ** internal memory allocation needs. "Core" in the previous sentence
2388 ** does not include operating-system specific VFS implementation. The
2389 ** Windows VFS uses native malloc() and free() for some operations.
2391 ** ^The sqlite3_malloc() routine returns a pointer to a block
2392 ** of memory at least N bytes in length, where N is the parameter.
2393 ** ^If sqlite3_malloc() is unable to obtain sufficient free
2394 ** memory, it returns a NULL pointer. ^If the parameter N to
2395 ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
2398 ** ^The sqlite3_malloc64(N) routine works just like
2399 ** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead
2400 ** of a signed 32-bit integer.
2402 ** ^Calling sqlite3_free() with a pointer previously returned
2403 ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
2404 ** that it might be reused. ^The sqlite3_free() routine is
2405 ** a no-op if is called with a NULL pointer. Passing a NULL pointer
2406 ** to sqlite3_free() is harmless. After being freed, memory
2407 ** should neither be read nor written. Even reading previously freed
2408 ** memory might result in a segmentation fault or other severe error.
2409 ** Memory corruption, a segmentation fault, or other severe error
2410 ** might result if sqlite3_free() is called with a non-NULL pointer that
2411 ** was not obtained from sqlite3_malloc() or sqlite3_realloc().
2413 ** ^The sqlite3_realloc(X,N) interface attempts to resize a
2414 ** prior memory allocation X to be at least N bytes.
2415 ** ^If the X parameter to sqlite3_realloc(X,N)
2416 ** is a NULL pointer then its behavior is identical to calling
2417 ** sqlite3_malloc(N).
2418 ** ^If the N parameter to sqlite3_realloc(X,N) is zero or
2419 ** negative then the behavior is exactly the same as calling
2421 ** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation
2422 ** of at least N bytes in size or NULL if insufficient memory is available.
2423 ** ^If M is the size of the prior allocation, then min(N,M) bytes
2424 ** of the prior allocation are copied into the beginning of buffer returned
2425 ** by sqlite3_realloc(X,N) and the prior allocation is freed.
2426 ** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the
2427 ** prior allocation is not freed.
2429 ** ^The sqlite3_realloc64(X,N) interfaces works the same as
2430 ** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead
2431 ** of a 32-bit signed integer.
2433 ** ^If X is a memory allocation previously obtained from sqlite3_malloc(),
2434 ** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then
2435 ** sqlite3_msize(X) returns the size of that memory allocation in bytes.
2436 ** ^The value returned by sqlite3_msize(X) might be larger than the number
2437 ** of bytes requested when X was allocated. ^If X is a NULL pointer then
2438 ** sqlite3_msize(X) returns zero. If X points to something that is not
2439 ** the beginning of memory allocation, or if it points to a formerly
2440 ** valid memory allocation that has now been freed, then the behavior
2441 ** of sqlite3_msize(X) is undefined and possibly harmful.
2443 ** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(),
2444 ** sqlite3_malloc64(), and sqlite3_realloc64()
2445 ** is always aligned to at least an 8 byte boundary, or to a
2446 ** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
2449 ** In SQLite version 3.5.0 and 3.5.1, it was possible to define
2450 ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in
2451 ** implementation of these routines to be omitted. That capability
2452 ** is no longer provided. Only built-in memory allocators can be used.
2454 ** Prior to SQLite version 3.7.10, the Windows OS interface layer called
2455 ** the system malloc() and free() directly when converting
2456 ** filenames between the UTF-8 encoding used by SQLite
2457 ** and whatever filename encoding is used by the particular Windows
2458 ** installation. Memory allocation errors were detected, but
2459 ** they were reported back as [SQLITE_CANTOPEN] or
2460 ** [SQLITE_IOERR] rather than [SQLITE_NOMEM].
2462 ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
2463 ** must be either NULL or else pointers obtained from a prior
2464 ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
2465 ** not yet been released.
2467 ** The application must not read or write any part of
2468 ** a block of memory after it has been released using
2469 ** [sqlite3_free()] or [sqlite3_realloc()].
2471 SQLITE_API void *SQLITE_STDCALL sqlite3_malloc(int);
2472 SQLITE_API void *SQLITE_STDCALL sqlite3_malloc64(sqlite3_uint64);
2473 SQLITE_API void *SQLITE_STDCALL sqlite3_realloc(void*, int);
2474 SQLITE_API void *SQLITE_STDCALL sqlite3_realloc64(void*, sqlite3_uint64);
2475 SQLITE_API void SQLITE_STDCALL sqlite3_free(void*);
2476 SQLITE_API sqlite3_uint64 SQLITE_STDCALL sqlite3_msize(void*);
2479 ** CAPI3REF: Memory Allocator Statistics
2481 ** SQLite provides these two interfaces for reporting on the status
2482 ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
2483 ** routines, which form the built-in memory allocation subsystem.
2485 ** ^The [sqlite3_memory_used()] routine returns the number of bytes
2486 ** of memory currently outstanding (malloced but not freed).
2487 ** ^The [sqlite3_memory_highwater()] routine returns the maximum
2488 ** value of [sqlite3_memory_used()] since the high-water mark
2489 ** was last reset. ^The values returned by [sqlite3_memory_used()] and
2490 ** [sqlite3_memory_highwater()] include any overhead
2491 ** added by SQLite in its implementation of [sqlite3_malloc()],
2492 ** but not overhead added by the any underlying system library
2493 ** routines that [sqlite3_malloc()] may call.
2495 ** ^The memory high-water mark is reset to the current value of
2496 ** [sqlite3_memory_used()] if and only if the parameter to
2497 ** [sqlite3_memory_highwater()] is true. ^The value returned
2498 ** by [sqlite3_memory_highwater(1)] is the high-water mark
2499 ** prior to the reset.
2501 SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_memory_used(void);
2502 SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_memory_highwater(int resetFlag);
2505 ** CAPI3REF: Pseudo-Random Number Generator
2507 ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
2508 ** select random [ROWID | ROWIDs] when inserting new records into a table that
2509 ** already uses the largest possible [ROWID]. The PRNG is also used for
2510 ** the build-in random() and randomblob() SQL functions. This interface allows
2511 ** applications to access the same PRNG for other purposes.
2513 ** ^A call to this routine stores N bytes of randomness into buffer P.
2514 ** ^The P parameter can be a NULL pointer.
2516 ** ^If this routine has not been previously called or if the previous
2517 ** call had N less than one or a NULL pointer for P, then the PRNG is
2518 ** seeded using randomness obtained from the xRandomness method of
2519 ** the default [sqlite3_vfs] object.
2520 ** ^If the previous call to this routine had an N of 1 or more and a
2521 ** non-NULL P then the pseudo-randomness is generated
2522 ** internally and without recourse to the [sqlite3_vfs] xRandomness
2525 SQLITE_API void SQLITE_STDCALL sqlite3_randomness(int N, void *P);
2528 ** CAPI3REF: Compile-Time Authorization Callbacks
2531 ** ^This routine registers an authorizer callback with a particular
2532 ** [database connection], supplied in the first argument.
2533 ** ^The authorizer callback is invoked as SQL statements are being compiled
2534 ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
2535 ** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various
2536 ** points during the compilation process, as logic is being created
2537 ** to perform various actions, the authorizer callback is invoked to
2538 ** see if those actions are allowed. ^The authorizer callback should
2539 ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
2540 ** specific action but allow the SQL statement to continue to be
2541 ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
2542 ** rejected with an error. ^If the authorizer callback returns
2543 ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
2544 ** then the [sqlite3_prepare_v2()] or equivalent call that triggered
2545 ** the authorizer will fail with an error message.
2547 ** When the callback returns [SQLITE_OK], that means the operation
2548 ** requested is ok. ^When the callback returns [SQLITE_DENY], the
2549 ** [sqlite3_prepare_v2()] or equivalent call that triggered the
2550 ** authorizer will fail with an error message explaining that
2551 ** access is denied.
2553 ** ^The first parameter to the authorizer callback is a copy of the third
2554 ** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
2555 ** to the callback is an integer [SQLITE_COPY | action code] that specifies
2556 ** the particular action to be authorized. ^The third through sixth parameters
2557 ** to the callback are zero-terminated strings that contain additional
2558 ** details about the action to be authorized.
2560 ** ^If the action code is [SQLITE_READ]
2561 ** and the callback returns [SQLITE_IGNORE] then the
2562 ** [prepared statement] statement is constructed to substitute
2563 ** a NULL value in place of the table column that would have
2564 ** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE]
2565 ** return can be used to deny an untrusted user access to individual
2566 ** columns of a table.
2567 ** ^If the action code is [SQLITE_DELETE] and the callback returns
2568 ** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
2569 ** [truncate optimization] is disabled and all rows are deleted individually.
2571 ** An authorizer is used when [sqlite3_prepare | preparing]
2572 ** SQL statements from an untrusted source, to ensure that the SQL statements
2573 ** do not try to access data they are not allowed to see, or that they do not
2574 ** try to execute malicious statements that damage the database. For
2575 ** example, an application may allow a user to enter arbitrary
2576 ** SQL queries for evaluation by a database. But the application does
2577 ** not want the user to be able to make arbitrary changes to the
2578 ** database. An authorizer could then be put in place while the
2579 ** user-entered SQL is being [sqlite3_prepare | prepared] that
2580 ** disallows everything except [SELECT] statements.
2582 ** Applications that need to process SQL from untrusted sources
2583 ** might also consider lowering resource limits using [sqlite3_limit()]
2584 ** and limiting database size using the [max_page_count] [PRAGMA]
2585 ** in addition to using an authorizer.
2587 ** ^(Only a single authorizer can be in place on a database connection
2588 ** at a time. Each call to sqlite3_set_authorizer overrides the
2589 ** previous call.)^ ^Disable the authorizer by installing a NULL callback.
2590 ** The authorizer is disabled by default.
2592 ** The authorizer callback must not do anything that will modify
2593 ** the database connection that invoked the authorizer callback.
2594 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2595 ** database connections for the meaning of "modify" in this paragraph.
2597 ** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
2598 ** statement might be re-prepared during [sqlite3_step()] due to a
2599 ** schema change. Hence, the application should ensure that the
2600 ** correct authorizer callback remains in place during the [sqlite3_step()].
2602 ** ^Note that the authorizer callback is invoked only during
2603 ** [sqlite3_prepare()] or its variants. Authorization is not
2604 ** performed during statement evaluation in [sqlite3_step()], unless
2605 ** as stated in the previous paragraph, sqlite3_step() invokes
2606 ** sqlite3_prepare_v2() to reprepare a statement after a schema change.
2608 SQLITE_API int SQLITE_STDCALL sqlite3_set_authorizer(
2610 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
2615 ** CAPI3REF: Authorizer Return Codes
2617 ** The [sqlite3_set_authorizer | authorizer callback function] must
2618 ** return either [SQLITE_OK] or one of these two constants in order
2619 ** to signal SQLite whether or not the action is permitted. See the
2620 ** [sqlite3_set_authorizer | authorizer documentation] for additional
2623 ** Note that SQLITE_IGNORE is also used as a [conflict resolution mode]
2624 ** returned from the [sqlite3_vtab_on_conflict()] interface.
2626 #define SQLITE_DENY 1 /* Abort the SQL statement with an error */
2627 #define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */
2630 ** CAPI3REF: Authorizer Action Codes
2632 ** The [sqlite3_set_authorizer()] interface registers a callback function
2633 ** that is invoked to authorize certain SQL statement actions. The
2634 ** second parameter to the callback is an integer code that specifies
2635 ** what action is being authorized. These are the integer action codes that
2636 ** the authorizer callback may be passed.
2638 ** These action code values signify what kind of operation is to be
2639 ** authorized. The 3rd and 4th parameters to the authorization
2640 ** callback function will be parameters or NULL depending on which of these
2641 ** codes is used as the second parameter. ^(The 5th parameter to the
2642 ** authorizer callback is the name of the database ("main", "temp",
2643 ** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback
2644 ** is the name of the inner-most trigger or view that is responsible for
2645 ** the access attempt or NULL if this access attempt is directly from
2646 ** top-level SQL code.
2648 /******************************************* 3rd ************ 4th ***********/
2649 #define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */
2650 #define SQLITE_CREATE_TABLE 2 /* Table Name NULL */
2651 #define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */
2652 #define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */
2653 #define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */
2654 #define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */
2655 #define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */
2656 #define SQLITE_CREATE_VIEW 8 /* View Name NULL */
2657 #define SQLITE_DELETE 9 /* Table Name NULL */
2658 #define SQLITE_DROP_INDEX 10 /* Index Name Table Name */
2659 #define SQLITE_DROP_TABLE 11 /* Table Name NULL */
2660 #define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */
2661 #define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */
2662 #define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */
2663 #define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */
2664 #define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */
2665 #define SQLITE_DROP_VIEW 17 /* View Name NULL */
2666 #define SQLITE_INSERT 18 /* Table Name NULL */
2667 #define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */
2668 #define SQLITE_READ 20 /* Table Name Column Name */
2669 #define SQLITE_SELECT 21 /* NULL NULL */
2670 #define SQLITE_TRANSACTION 22 /* Operation NULL */
2671 #define SQLITE_UPDATE 23 /* Table Name Column Name */
2672 #define SQLITE_ATTACH 24 /* Filename NULL */
2673 #define SQLITE_DETACH 25 /* Database Name NULL */
2674 #define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */
2675 #define SQLITE_REINDEX 27 /* Index Name NULL */
2676 #define SQLITE_ANALYZE 28 /* Table Name NULL */
2677 #define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */
2678 #define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */
2679 #define SQLITE_FUNCTION 31 /* NULL Function Name */
2680 #define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */
2681 #define SQLITE_COPY 0 /* No longer used */
2682 #define SQLITE_RECURSIVE 33 /* NULL NULL */
2685 ** CAPI3REF: Tracing And Profiling Functions
2688 ** These routines register callback functions that can be used for
2689 ** tracing and profiling the execution of SQL statements.
2691 ** ^The callback function registered by sqlite3_trace() is invoked at
2692 ** various times when an SQL statement is being run by [sqlite3_step()].
2693 ** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
2694 ** SQL statement text as the statement first begins executing.
2695 ** ^(Additional sqlite3_trace() callbacks might occur
2696 ** as each triggered subprogram is entered. The callbacks for triggers
2697 ** contain a UTF-8 SQL comment that identifies the trigger.)^
2699 ** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit
2700 ** the length of [bound parameter] expansion in the output of sqlite3_trace().
2702 ** ^The callback function registered by sqlite3_profile() is invoked
2703 ** as each SQL statement finishes. ^The profile callback contains
2704 ** the original statement text and an estimate of wall-clock time
2705 ** of how long that statement took to run. ^The profile callback
2706 ** time is in units of nanoseconds, however the current implementation
2707 ** is only capable of millisecond resolution so the six least significant
2708 ** digits in the time are meaningless. Future versions of SQLite
2709 ** might provide greater resolution on the profiler callback. The
2710 ** sqlite3_profile() function is considered experimental and is
2711 ** subject to change in future versions of SQLite.
2713 SQLITE_API void *SQLITE_STDCALL sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*);
2714 SQLITE_API SQLITE_EXPERIMENTAL void *SQLITE_STDCALL sqlite3_profile(sqlite3*,
2715 void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
2718 ** CAPI3REF: Query Progress Callbacks
2721 ** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
2722 ** function X to be invoked periodically during long running calls to
2723 ** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for
2724 ** database connection D. An example use for this
2725 ** interface is to keep a GUI updated during a large query.
2727 ** ^The parameter P is passed through as the only parameter to the
2728 ** callback function X. ^The parameter N is the approximate number of
2729 ** [virtual machine instructions] that are evaluated between successive
2730 ** invocations of the callback X. ^If N is less than one then the progress
2731 ** handler is disabled.
2733 ** ^Only a single progress handler may be defined at one time per
2734 ** [database connection]; setting a new progress handler cancels the
2735 ** old one. ^Setting parameter X to NULL disables the progress handler.
2736 ** ^The progress handler is also disabled by setting N to a value less
2739 ** ^If the progress callback returns non-zero, the operation is
2740 ** interrupted. This feature can be used to implement a
2741 ** "Cancel" button on a GUI progress dialog box.
2743 ** The progress handler callback must not do anything that will modify
2744 ** the database connection that invoked the progress handler.
2745 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2746 ** database connections for the meaning of "modify" in this paragraph.
2749 SQLITE_API void SQLITE_STDCALL sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
2752 ** CAPI3REF: Opening A New Database Connection
2753 ** CONSTRUCTOR: sqlite3
2755 ** ^These routines open an SQLite database file as specified by the
2756 ** filename argument. ^The filename argument is interpreted as UTF-8 for
2757 ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
2758 ** order for sqlite3_open16(). ^(A [database connection] handle is usually
2759 ** returned in *ppDb, even if an error occurs. The only exception is that
2760 ** if SQLite is unable to allocate memory to hold the [sqlite3] object,
2761 ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
2762 ** object.)^ ^(If the database is opened (and/or created) successfully, then
2763 ** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The
2764 ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
2765 ** an English language description of the error following a failure of any
2766 ** of the sqlite3_open() routines.
2768 ** ^The default encoding will be UTF-8 for databases created using
2769 ** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases
2770 ** created using sqlite3_open16() will be UTF-16 in the native byte order.
2772 ** Whether or not an error occurs when it is opened, resources
2773 ** associated with the [database connection] handle should be released by
2774 ** passing it to [sqlite3_close()] when it is no longer required.
2776 ** The sqlite3_open_v2() interface works like sqlite3_open()
2777 ** except that it accepts two additional parameters for additional control
2778 ** over the new database connection. ^(The flags parameter to
2779 ** sqlite3_open_v2() can take one of
2780 ** the following three values, optionally combined with the
2781 ** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE],
2782 ** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^
2785 ** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
2786 ** <dd>The database is opened in read-only mode. If the database does not
2787 ** already exist, an error is returned.</dd>)^
2789 ** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
2790 ** <dd>The database is opened for reading and writing if possible, or reading
2791 ** only if the file is write protected by the operating system. In either
2792 ** case the database must already exist, otherwise an error is returned.</dd>)^
2794 ** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
2795 ** <dd>The database is opened for reading and writing, and is created if
2796 ** it does not already exist. This is the behavior that is always used for
2797 ** sqlite3_open() and sqlite3_open16().</dd>)^
2800 ** If the 3rd parameter to sqlite3_open_v2() is not one of the
2801 ** combinations shown above optionally combined with other
2802 ** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits]
2803 ** then the behavior is undefined.
2805 ** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection
2806 ** opens in the multi-thread [threading mode] as long as the single-thread
2807 ** mode has not been set at compile-time or start-time. ^If the
2808 ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens
2809 ** in the serialized [threading mode] unless single-thread was
2810 ** previously selected at compile-time or start-time.
2811 ** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be
2812 ** eligible to use [shared cache mode], regardless of whether or not shared
2813 ** cache is enabled using [sqlite3_enable_shared_cache()]. ^The
2814 ** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not
2815 ** participate in [shared cache mode] even if it is enabled.
2817 ** ^The fourth parameter to sqlite3_open_v2() is the name of the
2818 ** [sqlite3_vfs] object that defines the operating system interface that
2819 ** the new database connection should use. ^If the fourth parameter is
2820 ** a NULL pointer then the default [sqlite3_vfs] object is used.
2822 ** ^If the filename is ":memory:", then a private, temporary in-memory database
2823 ** is created for the connection. ^This in-memory database will vanish when
2824 ** the database connection is closed. Future versions of SQLite might
2825 ** make use of additional special filenames that begin with the ":" character.
2826 ** It is recommended that when a database filename actually does begin with
2827 ** a ":" character you should prefix the filename with a pathname such as
2828 ** "./" to avoid ambiguity.
2830 ** ^If the filename is an empty string, then a private, temporary
2831 ** on-disk database will be created. ^This private database will be
2832 ** automatically deleted as soon as the database connection is closed.
2834 ** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
2836 ** ^If [URI filename] interpretation is enabled, and the filename argument
2837 ** begins with "file:", then the filename is interpreted as a URI. ^URI
2838 ** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
2839 ** set in the fourth argument to sqlite3_open_v2(), or if it has
2840 ** been enabled globally using the [SQLITE_CONFIG_URI] option with the
2841 ** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
2842 ** As of SQLite version 3.7.7, URI filename interpretation is turned off
2843 ** by default, but future releases of SQLite might enable URI filename
2844 ** interpretation by default. See "[URI filenames]" for additional
2847 ** URI filenames are parsed according to RFC 3986. ^If the URI contains an
2848 ** authority, then it must be either an empty string or the string
2849 ** "localhost". ^If the authority is not an empty string or "localhost", an
2850 ** error is returned to the caller. ^The fragment component of a URI, if
2851 ** present, is ignored.
2853 ** ^SQLite uses the path component of the URI as the name of the disk file
2854 ** which contains the database. ^If the path begins with a '/' character,
2855 ** then it is interpreted as an absolute path. ^If the path does not begin
2856 ** with a '/' (meaning that the authority section is omitted from the URI)
2857 ** then the path is interpreted as a relative path.
2858 ** ^(On windows, the first component of an absolute path
2859 ** is a drive specification (e.g. "C:").)^
2861 ** [[core URI query parameters]]
2862 ** The query component of a URI may contain parameters that are interpreted
2863 ** either by SQLite itself, or by a [VFS | custom VFS implementation].
2864 ** SQLite and its built-in [VFSes] interpret the
2865 ** following query parameters:
2868 ** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
2869 ** a VFS object that provides the operating system interface that should
2870 ** be used to access the database file on disk. ^If this option is set to
2871 ** an empty string the default VFS object is used. ^Specifying an unknown
2872 ** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
2873 ** present, then the VFS specified by the option takes precedence over
2874 ** the value passed as the fourth parameter to sqlite3_open_v2().
2876 ** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw",
2877 ** "rwc", or "memory". Attempting to set it to any other value is
2879 ** ^If "ro" is specified, then the database is opened for read-only
2880 ** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the
2881 ** third argument to sqlite3_open_v2(). ^If the mode option is set to
2882 ** "rw", then the database is opened for read-write (but not create)
2883 ** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had
2884 ** been set. ^Value "rwc" is equivalent to setting both
2885 ** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is
2886 ** set to "memory" then a pure [in-memory database] that never reads
2887 ** or writes from disk is used. ^It is an error to specify a value for
2888 ** the mode parameter that is less restrictive than that specified by
2889 ** the flags passed in the third parameter to sqlite3_open_v2().
2891 ** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
2892 ** "private". ^Setting it to "shared" is equivalent to setting the
2893 ** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
2894 ** sqlite3_open_v2(). ^Setting the cache parameter to "private" is
2895 ** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
2896 ** ^If sqlite3_open_v2() is used and the "cache" parameter is present in
2897 ** a URI filename, its value overrides any behavior requested by setting
2898 ** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.
2900 ** <li> <b>psow</b>: ^The psow parameter indicates whether or not the
2901 ** [powersafe overwrite] property does or does not apply to the
2902 ** storage media on which the database file resides.
2904 ** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter
2905 ** which if set disables file locking in rollback journal modes. This
2906 ** is useful for accessing a database on a filesystem that does not
2907 ** support locking. Caution: Database corruption might result if two
2908 ** or more processes write to the same database and any one of those
2909 ** processes uses nolock=1.
2911 ** <li> <b>immutable</b>: ^The immutable parameter is a boolean query
2912 ** parameter that indicates that the database file is stored on
2913 ** read-only media. ^When immutable is set, SQLite assumes that the
2914 ** database file cannot be changed, even by a process with higher
2915 ** privilege, and so the database is opened read-only and all locking
2916 ** and change detection is disabled. Caution: Setting the immutable
2917 ** property on a database file that does in fact change can result
2918 ** in incorrect query results and/or [SQLITE_CORRUPT] errors.
2919 ** See also: [SQLITE_IOCAP_IMMUTABLE].
2923 ** ^Specifying an unknown parameter in the query component of a URI is not an
2924 ** error. Future versions of SQLite might understand additional query
2925 ** parameters. See "[query parameters with special meaning to SQLite]" for
2926 ** additional information.
2928 ** [[URI filename examples]] <h3>URI filename examples</h3>
2930 ** <table border="1" align=center cellpadding=5>
2931 ** <tr><th> URI filenames <th> Results
2932 ** <tr><td> file:data.db <td>
2933 ** Open the file "data.db" in the current directory.
2934 ** <tr><td> file:/home/fred/data.db<br>
2935 ** file:///home/fred/data.db <br>
2936 ** file://localhost/home/fred/data.db <br> <td>
2937 ** Open the database file "/home/fred/data.db".
2938 ** <tr><td> file://darkstar/home/fred/data.db <td>
2939 ** An error. "darkstar" is not a recognized authority.
2940 ** <tr><td style="white-space:nowrap">
2941 ** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
2942 ** <td> Windows only: Open the file "data.db" on fred's desktop on drive
2943 ** C:. Note that the %20 escaping in this example is not strictly
2944 ** necessary - space characters can be used literally
2945 ** in URI filenames.
2946 ** <tr><td> file:data.db?mode=ro&cache=private <td>
2947 ** Open file "data.db" in the current directory for read-only access.
2948 ** Regardless of whether or not shared-cache mode is enabled by
2949 ** default, use a private cache.
2950 ** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td>
2951 ** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile"
2952 ** that uses dot-files in place of posix advisory locking.
2953 ** <tr><td> file:data.db?mode=readonly <td>
2954 ** An error. "readonly" is not a valid option for the "mode" parameter.
2957 ** ^URI hexadecimal escape sequences (%HH) are supported within the path and
2958 ** query components of a URI. A hexadecimal escape sequence consists of a
2959 ** percent sign - "%" - followed by exactly two hexadecimal digits
2960 ** specifying an octet value. ^Before the path or query components of a
2961 ** URI filename are interpreted, they are encoded using UTF-8 and all
2962 ** hexadecimal escape sequences replaced by a single byte containing the
2963 ** corresponding octet. If this process generates an invalid UTF-8 encoding,
2964 ** the results are undefined.
2966 ** <b>Note to Windows users:</b> The encoding used for the filename argument
2967 ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
2968 ** codepage is currently defined. Filenames containing international
2969 ** characters must be converted to UTF-8 prior to passing them into
2970 ** sqlite3_open() or sqlite3_open_v2().
2972 ** <b>Note to Windows Runtime users:</b> The temporary directory must be set
2973 ** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various
2974 ** features that require the use of temporary files may fail.
2976 ** See also: [sqlite3_temp_directory]
2978 SQLITE_API int SQLITE_STDCALL sqlite3_open(
2979 const char *filename, /* Database filename (UTF-8) */
2980 sqlite3 **ppDb /* OUT: SQLite db handle */
2982 SQLITE_API int SQLITE_STDCALL sqlite3_open16(
2983 const void *filename, /* Database filename (UTF-16) */
2984 sqlite3 **ppDb /* OUT: SQLite db handle */
2986 SQLITE_API int SQLITE_STDCALL sqlite3_open_v2(
2987 const char *filename, /* Database filename (UTF-8) */
2988 sqlite3 **ppDb, /* OUT: SQLite db handle */
2989 int flags, /* Flags */
2990 const char *zVfs /* Name of VFS module to use */
2994 ** CAPI3REF: Obtain Values For URI Parameters
2996 ** These are utility routines, useful to VFS implementations, that check
2997 ** to see if a database file was a URI that contained a specific query
2998 ** parameter, and if so obtains the value of that query parameter.
3000 ** If F is the database filename pointer passed into the xOpen() method of
3001 ** a VFS implementation when the flags parameter to xOpen() has one or
3002 ** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and
3003 ** P is the name of the query parameter, then
3004 ** sqlite3_uri_parameter(F,P) returns the value of the P
3005 ** parameter if it exists or a NULL pointer if P does not appear as a
3006 ** query parameter on F. If P is a query parameter of F
3007 ** has no explicit value, then sqlite3_uri_parameter(F,P) returns
3008 ** a pointer to an empty string.
3010 ** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
3011 ** parameter and returns true (1) or false (0) according to the value
3012 ** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
3013 ** value of query parameter P is one of "yes", "true", or "on" in any
3014 ** case or if the value begins with a non-zero number. The
3015 ** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
3016 ** query parameter P is one of "no", "false", or "off" in any case or
3017 ** if the value begins with a numeric zero. If P is not a query
3018 ** parameter on F or if the value of P is does not match any of the
3019 ** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).
3021 ** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
3022 ** 64-bit signed integer and returns that integer, or D if P does not
3023 ** exist. If the value of P is something other than an integer, then
3024 ** zero is returned.
3026 ** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
3027 ** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and
3028 ** is not a database file pathname pointer that SQLite passed into the xOpen
3029 ** VFS method, then the behavior of this routine is undefined and probably
3032 SQLITE_API const char *SQLITE_STDCALL sqlite3_uri_parameter(const char *zFilename, const char *zParam);
3033 SQLITE_API int SQLITE_STDCALL sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault);
3034 SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_uri_int64(const char*, const char*, sqlite3_int64);
3038 ** CAPI3REF: Error Codes And Messages
3041 ** ^If the most recent sqlite3_* API call associated with
3042 ** [database connection] D failed, then the sqlite3_errcode(D) interface
3043 ** returns the numeric [result code] or [extended result code] for that
3045 ** If the most recent API call was successful,
3046 ** then the return value from sqlite3_errcode() is undefined.
3047 ** ^The sqlite3_extended_errcode()
3048 ** interface is the same except that it always returns the
3049 ** [extended result code] even when extended result codes are
3052 ** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
3053 ** text that describes the error, as either UTF-8 or UTF-16 respectively.
3054 ** ^(Memory to hold the error message string is managed internally.
3055 ** The application does not need to worry about freeing the result.
3056 ** However, the error string might be overwritten or deallocated by
3057 ** subsequent calls to other SQLite interface functions.)^
3059 ** ^The sqlite3_errstr() interface returns the English-language text
3060 ** that describes the [result code], as UTF-8.
3061 ** ^(Memory to hold the error message string is managed internally
3062 ** and must not be freed by the application)^.
3064 ** When the serialized [threading mode] is in use, it might be the
3065 ** case that a second error occurs on a separate thread in between
3066 ** the time of the first error and the call to these interfaces.
3067 ** When that happens, the second error will be reported since these
3068 ** interfaces always report the most recent result. To avoid
3069 ** this, each thread can obtain exclusive use of the [database connection] D
3070 ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
3071 ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
3072 ** all calls to the interfaces listed here are completed.
3074 ** If an interface fails with SQLITE_MISUSE, that means the interface
3075 ** was invoked incorrectly by the application. In that case, the
3076 ** error code and message may or may not be set.
3078 SQLITE_API int SQLITE_STDCALL sqlite3_errcode(sqlite3 *db);
3079 SQLITE_API int SQLITE_STDCALL sqlite3_extended_errcode(sqlite3 *db);
3080 SQLITE_API const char *SQLITE_STDCALL sqlite3_errmsg(sqlite3*);
3081 SQLITE_API const void *SQLITE_STDCALL sqlite3_errmsg16(sqlite3*);
3082 SQLITE_API const char *SQLITE_STDCALL sqlite3_errstr(int);
3085 ** CAPI3REF: Prepared Statement Object
3086 ** KEYWORDS: {prepared statement} {prepared statements}
3088 ** An instance of this object represents a single SQL statement that
3089 ** has been compiled into binary form and is ready to be evaluated.
3091 ** Think of each SQL statement as a separate computer program. The
3092 ** original SQL text is source code. A prepared statement object
3093 ** is the compiled object code. All SQL must be converted into a
3094 ** prepared statement before it can be run.
3096 ** The life-cycle of a prepared statement object usually goes like this:
3099 ** <li> Create the prepared statement object using [sqlite3_prepare_v2()].
3100 ** <li> Bind values to [parameters] using the sqlite3_bind_*()
3102 ** <li> Run the SQL by calling [sqlite3_step()] one or more times.
3103 ** <li> Reset the prepared statement using [sqlite3_reset()] then go back
3104 ** to step 2. Do this zero or more times.
3105 ** <li> Destroy the object using [sqlite3_finalize()].
3108 typedef struct sqlite3_stmt sqlite3_stmt;
3111 ** CAPI3REF: Run-time Limits
3114 ** ^(This interface allows the size of various constructs to be limited
3115 ** on a connection by connection basis. The first parameter is the
3116 ** [database connection] whose limit is to be set or queried. The
3117 ** second parameter is one of the [limit categories] that define a
3118 ** class of constructs to be size limited. The third parameter is the
3119 ** new limit for that construct.)^
3121 ** ^If the new limit is a negative number, the limit is unchanged.
3122 ** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
3123 ** [limits | hard upper bound]
3124 ** set at compile-time by a C preprocessor macro called
3125 ** [limits | SQLITE_MAX_<i>NAME</i>].
3126 ** (The "_LIMIT_" in the name is changed to "_MAX_".))^
3127 ** ^Attempts to increase a limit above its hard upper bound are
3128 ** silently truncated to the hard upper bound.
3130 ** ^Regardless of whether or not the limit was changed, the
3131 ** [sqlite3_limit()] interface returns the prior value of the limit.
3132 ** ^Hence, to find the current value of a limit without changing it,
3133 ** simply invoke this interface with the third parameter set to -1.
3135 ** Run-time limits are intended for use in applications that manage
3136 ** both their own internal database and also databases that are controlled
3137 ** by untrusted external sources. An example application might be a
3138 ** web browser that has its own databases for storing history and
3139 ** separate databases controlled by JavaScript applications downloaded
3140 ** off the Internet. The internal databases can be given the
3141 ** large, default limits. Databases managed by external sources can
3142 ** be given much smaller limits designed to prevent a denial of service
3143 ** attack. Developers might also want to use the [sqlite3_set_authorizer()]
3144 ** interface to further control untrusted SQL. The size of the database
3145 ** created by an untrusted script can be contained using the
3146 ** [max_page_count] [PRAGMA].
3148 ** New run-time limit categories may be added in future releases.
3150 SQLITE_API int SQLITE_STDCALL sqlite3_limit(sqlite3*, int id, int newVal);
3153 ** CAPI3REF: Run-Time Limit Categories
3154 ** KEYWORDS: {limit category} {*limit categories}
3156 ** These constants define various performance limits
3157 ** that can be lowered at run-time using [sqlite3_limit()].
3158 ** The synopsis of the meanings of the various limits is shown below.
3159 ** Additional information is available at [limits | Limits in SQLite].
3162 ** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt>
3163 ** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
3165 ** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
3166 ** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
3168 ** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt>
3169 ** <dd>The maximum number of columns in a table definition or in the
3170 ** result set of a [SELECT] or the maximum number of columns in an index
3171 ** or in an ORDER BY or GROUP BY clause.</dd>)^
3173 ** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
3174 ** <dd>The maximum depth of the parse tree on any expression.</dd>)^
3176 ** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
3177 ** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
3179 ** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
3180 ** <dd>The maximum number of instructions in a virtual machine program
3181 ** used to implement an SQL statement. This limit is not currently
3182 ** enforced, though that might be added in some future release of
3185 ** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
3186 ** <dd>The maximum number of arguments on a function.</dd>)^
3188 ** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
3189 ** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
3191 ** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]]
3192 ** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
3193 ** <dd>The maximum length of the pattern argument to the [LIKE] or
3194 ** [GLOB] operators.</dd>)^
3196 ** [[SQLITE_LIMIT_VARIABLE_NUMBER]]
3197 ** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
3198 ** <dd>The maximum index number of any [parameter] in an SQL statement.)^
3200 ** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
3201 ** <dd>The maximum depth of recursion for triggers.</dd>)^
3203 ** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt>
3204 ** <dd>The maximum number of auxiliary worker threads that a single
3205 ** [prepared statement] may start.</dd>)^
3208 #define SQLITE_LIMIT_LENGTH 0
3209 #define SQLITE_LIMIT_SQL_LENGTH 1
3210 #define SQLITE_LIMIT_COLUMN 2
3211 #define SQLITE_LIMIT_EXPR_DEPTH 3
3212 #define SQLITE_LIMIT_COMPOUND_SELECT 4
3213 #define SQLITE_LIMIT_VDBE_OP 5
3214 #define SQLITE_LIMIT_FUNCTION_ARG 6
3215 #define SQLITE_LIMIT_ATTACHED 7
3216 #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8
3217 #define SQLITE_LIMIT_VARIABLE_NUMBER 9
3218 #define SQLITE_LIMIT_TRIGGER_DEPTH 10
3219 #define SQLITE_LIMIT_WORKER_THREADS 11
3222 ** CAPI3REF: Compiling An SQL Statement
3223 ** KEYWORDS: {SQL statement compiler}
3225 ** CONSTRUCTOR: sqlite3_stmt
3227 ** To execute an SQL query, it must first be compiled into a byte-code
3228 ** program using one of these routines.
3230 ** The first argument, "db", is a [database connection] obtained from a
3231 ** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
3232 ** [sqlite3_open16()]. The database connection must not have been closed.
3234 ** The second argument, "zSql", is the statement to be compiled, encoded
3235 ** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2()
3236 ** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2()
3239 ** ^If the nByte argument is negative, then zSql is read up to the
3240 ** first zero terminator. ^If nByte is positive, then it is the
3241 ** number of bytes read from zSql. ^If nByte is zero, then no prepared
3242 ** statement is generated.
3243 ** If the caller knows that the supplied string is nul-terminated, then
3244 ** there is a small performance advantage to passing an nByte parameter that
3245 ** is the number of bytes in the input string <i>including</i>
3246 ** the nul-terminator.
3248 ** ^If pzTail is not NULL then *pzTail is made to point to the first byte
3249 ** past the end of the first SQL statement in zSql. These routines only
3250 ** compile the first statement in zSql, so *pzTail is left pointing to
3251 ** what remains uncompiled.
3253 ** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
3254 ** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set
3255 ** to NULL. ^If the input text contains no SQL (if the input is an empty
3256 ** string or a comment) then *ppStmt is set to NULL.
3257 ** The calling procedure is responsible for deleting the compiled
3258 ** SQL statement using [sqlite3_finalize()] after it has finished with it.
3259 ** ppStmt may not be NULL.
3261 ** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
3262 ** otherwise an [error code] is returned.
3264 ** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are
3265 ** recommended for all new programs. The two older interfaces are retained
3266 ** for backwards compatibility, but their use is discouraged.
3267 ** ^In the "v2" interfaces, the prepared statement
3268 ** that is returned (the [sqlite3_stmt] object) contains a copy of the
3269 ** original SQL text. This causes the [sqlite3_step()] interface to
3270 ** behave differently in three ways:
3274 ** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
3275 ** always used to do, [sqlite3_step()] will automatically recompile the SQL
3276 ** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY]
3277 ** retries will occur before sqlite3_step() gives up and returns an error.
3281 ** ^When an error occurs, [sqlite3_step()] will return one of the detailed
3282 ** [error codes] or [extended error codes]. ^The legacy behavior was that
3283 ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
3284 ** and the application would have to make a second call to [sqlite3_reset()]
3285 ** in order to find the underlying cause of the problem. With the "v2" prepare
3286 ** interfaces, the underlying reason for the error is returned immediately.
3290 ** ^If the specific value bound to [parameter | host parameter] in the
3291 ** WHERE clause might influence the choice of query plan for a statement,
3292 ** then the statement will be automatically recompiled, as if there had been
3293 ** a schema change, on the first [sqlite3_step()] call following any change
3294 ** to the [sqlite3_bind_text | bindings] of that [parameter].
3295 ** ^The specific value of WHERE-clause [parameter] might influence the
3296 ** choice of query plan if the parameter is the left-hand side of a [LIKE]
3297 ** or [GLOB] operator or if the parameter is compared to an indexed column
3298 ** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled.
3302 SQLITE_API int SQLITE_STDCALL sqlite3_prepare(
3303 sqlite3 *db, /* Database handle */
3304 const char *zSql, /* SQL statement, UTF-8 encoded */
3305 int nByte, /* Maximum length of zSql in bytes. */
3306 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3307 const char **pzTail /* OUT: Pointer to unused portion of zSql */
3309 SQLITE_API int SQLITE_STDCALL sqlite3_prepare_v2(
3310 sqlite3 *db, /* Database handle */
3311 const char *zSql, /* SQL statement, UTF-8 encoded */
3312 int nByte, /* Maximum length of zSql in bytes. */
3313 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3314 const char **pzTail /* OUT: Pointer to unused portion of zSql */
3316 SQLITE_API int SQLITE_STDCALL sqlite3_prepare16(
3317 sqlite3 *db, /* Database handle */
3318 const void *zSql, /* SQL statement, UTF-16 encoded */
3319 int nByte, /* Maximum length of zSql in bytes. */
3320 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3321 const void **pzTail /* OUT: Pointer to unused portion of zSql */
3323 SQLITE_API int SQLITE_STDCALL sqlite3_prepare16_v2(
3324 sqlite3 *db, /* Database handle */
3325 const void *zSql, /* SQL statement, UTF-16 encoded */
3326 int nByte, /* Maximum length of zSql in bytes. */
3327 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3328 const void **pzTail /* OUT: Pointer to unused portion of zSql */
3332 ** CAPI3REF: Retrieving Statement SQL
3333 ** METHOD: sqlite3_stmt
3335 ** ^This interface can be used to retrieve a saved copy of the original
3336 ** SQL text used to create a [prepared statement] if that statement was
3337 ** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()].
3339 SQLITE_API const char *SQLITE_STDCALL sqlite3_sql(sqlite3_stmt *pStmt);
3342 ** CAPI3REF: Determine If An SQL Statement Writes The Database
3343 ** METHOD: sqlite3_stmt
3345 ** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
3346 ** and only if the [prepared statement] X makes no direct changes to
3347 ** the content of the database file.
3349 ** Note that [application-defined SQL functions] or
3350 ** [virtual tables] might change the database indirectly as a side effect.
3351 ** ^(For example, if an application defines a function "eval()" that
3352 ** calls [sqlite3_exec()], then the following SQL statement would
3353 ** change the database file through side-effects:
3355 ** <blockquote><pre>
3356 ** SELECT eval('DELETE FROM t1') FROM t2;
3357 ** </pre></blockquote>
3359 ** But because the [SELECT] statement does not change the database file
3360 ** directly, sqlite3_stmt_readonly() would still return true.)^
3362 ** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
3363 ** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
3364 ** since the statements themselves do not actually modify the database but
3365 ** rather they control the timing of when other statements modify the
3366 ** database. ^The [ATTACH] and [DETACH] statements also cause
3367 ** sqlite3_stmt_readonly() to return true since, while those statements
3368 ** change the configuration of a database connection, they do not make
3369 ** changes to the content of the database files on disk.
3371 SQLITE_API int SQLITE_STDCALL sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
3374 ** CAPI3REF: Determine If A Prepared Statement Has Been Reset
3375 ** METHOD: sqlite3_stmt
3377 ** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
3378 ** [prepared statement] S has been stepped at least once using
3379 ** [sqlite3_step(S)] but has neither run to completion (returned
3380 ** [SQLITE_DONE] from [sqlite3_step(S)]) nor
3381 ** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S)
3382 ** interface returns false if S is a NULL pointer. If S is not a
3383 ** NULL pointer and is not a pointer to a valid [prepared statement]
3384 ** object, then the behavior is undefined and probably undesirable.
3386 ** This interface can be used in combination [sqlite3_next_stmt()]
3387 ** to locate all prepared statements associated with a database
3388 ** connection that are in need of being reset. This can be used,
3389 ** for example, in diagnostic routines to search for prepared
3390 ** statements that are holding a transaction open.
3392 SQLITE_API int SQLITE_STDCALL sqlite3_stmt_busy(sqlite3_stmt*);
3395 ** CAPI3REF: Dynamically Typed Value Object
3396 ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
3398 ** SQLite uses the sqlite3_value object to represent all values
3399 ** that can be stored in a database table. SQLite uses dynamic typing
3400 ** for the values it stores. ^Values stored in sqlite3_value objects
3401 ** can be integers, floating point values, strings, BLOBs, or NULL.
3403 ** An sqlite3_value object may be either "protected" or "unprotected".
3404 ** Some interfaces require a protected sqlite3_value. Other interfaces
3405 ** will accept either a protected or an unprotected sqlite3_value.
3406 ** Every interface that accepts sqlite3_value arguments specifies
3407 ** whether or not it requires a protected sqlite3_value. The
3408 ** [sqlite3_value_dup()] interface can be used to construct a new
3409 ** protected sqlite3_value from an unprotected sqlite3_value.
3411 ** The terms "protected" and "unprotected" refer to whether or not
3412 ** a mutex is held. An internal mutex is held for a protected
3413 ** sqlite3_value object but no mutex is held for an unprotected
3414 ** sqlite3_value object. If SQLite is compiled to be single-threaded
3415 ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
3416 ** or if SQLite is run in one of reduced mutex modes
3417 ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
3418 ** then there is no distinction between protected and unprotected
3419 ** sqlite3_value objects and they can be used interchangeably. However,
3420 ** for maximum code portability it is recommended that applications
3421 ** still make the distinction between protected and unprotected
3422 ** sqlite3_value objects even when not strictly required.
3424 ** ^The sqlite3_value objects that are passed as parameters into the
3425 ** implementation of [application-defined SQL functions] are protected.
3426 ** ^The sqlite3_value object returned by
3427 ** [sqlite3_column_value()] is unprotected.
3428 ** Unprotected sqlite3_value objects may only be used with
3429 ** [sqlite3_result_value()] and [sqlite3_bind_value()].
3430 ** The [sqlite3_value_blob | sqlite3_value_type()] family of
3431 ** interfaces require protected sqlite3_value objects.
3433 typedef struct Mem sqlite3_value;
3436 ** CAPI3REF: SQL Function Context Object
3438 ** The context in which an SQL function executes is stored in an
3439 ** sqlite3_context object. ^A pointer to an sqlite3_context object
3440 ** is always first parameter to [application-defined SQL functions].
3441 ** The application-defined SQL function implementation will pass this
3442 ** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
3443 ** [sqlite3_aggregate_context()], [sqlite3_user_data()],
3444 ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
3445 ** and/or [sqlite3_set_auxdata()].
3447 typedef struct sqlite3_context sqlite3_context;
3450 ** CAPI3REF: Binding Values To Prepared Statements
3451 ** KEYWORDS: {host parameter} {host parameters} {host parameter name}
3452 ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
3453 ** METHOD: sqlite3_stmt
3455 ** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
3456 ** literals may be replaced by a [parameter] that matches one of following
3467 ** In the templates above, NNN represents an integer literal,
3468 ** and VVV represents an alphanumeric identifier.)^ ^The values of these
3469 ** parameters (also called "host parameter names" or "SQL parameters")
3470 ** can be set using the sqlite3_bind_*() routines defined here.
3472 ** ^The first argument to the sqlite3_bind_*() routines is always
3473 ** a pointer to the [sqlite3_stmt] object returned from
3474 ** [sqlite3_prepare_v2()] or its variants.
3476 ** ^The second argument is the index of the SQL parameter to be set.
3477 ** ^The leftmost SQL parameter has an index of 1. ^When the same named
3478 ** SQL parameter is used more than once, second and subsequent
3479 ** occurrences have the same index as the first occurrence.
3480 ** ^The index for named parameters can be looked up using the
3481 ** [sqlite3_bind_parameter_index()] API if desired. ^The index
3482 ** for "?NNN" parameters is the value of NNN.
3483 ** ^The NNN value must be between 1 and the [sqlite3_limit()]
3484 ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999).
3486 ** ^The third argument is the value to bind to the parameter.
3487 ** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16()
3488 ** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter
3489 ** is ignored and the end result is the same as sqlite3_bind_null().
3491 ** ^(In those routines that have a fourth argument, its value is the
3492 ** number of bytes in the parameter. To be clear: the value is the
3493 ** number of <u>bytes</u> in the value, not the number of characters.)^
3494 ** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()
3495 ** is negative, then the length of the string is
3496 ** the number of bytes up to the first zero terminator.
3497 ** If the fourth parameter to sqlite3_bind_blob() is negative, then
3498 ** the behavior is undefined.
3499 ** If a non-negative fourth parameter is provided to sqlite3_bind_text()
3500 ** or sqlite3_bind_text16() or sqlite3_bind_text64() then
3501 ** that parameter must be the byte offset
3502 ** where the NUL terminator would occur assuming the string were NUL
3503 ** terminated. If any NUL characters occur at byte offsets less than
3504 ** the value of the fourth parameter then the resulting string value will
3505 ** contain embedded NULs. The result of expressions involving strings
3506 ** with embedded NULs is undefined.
3508 ** ^The fifth argument to the BLOB and string binding interfaces
3509 ** is a destructor used to dispose of the BLOB or
3510 ** string after SQLite has finished with it. ^The destructor is called
3511 ** to dispose of the BLOB or string even if the call to bind API fails.
3512 ** ^If the fifth argument is
3513 ** the special value [SQLITE_STATIC], then SQLite assumes that the
3514 ** information is in static, unmanaged space and does not need to be freed.
3515 ** ^If the fifth argument has the value [SQLITE_TRANSIENT], then
3516 ** SQLite makes its own private copy of the data immediately, before
3517 ** the sqlite3_bind_*() routine returns.
3519 ** ^The sixth argument to sqlite3_bind_text64() must be one of
3520 ** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]
3521 ** to specify the encoding of the text in the third parameter. If
3522 ** the sixth argument to sqlite3_bind_text64() is not one of the
3523 ** allowed values shown above, or if the text encoding is different
3524 ** from the encoding specified by the sixth parameter, then the behavior
3527 ** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
3528 ** is filled with zeroes. ^A zeroblob uses a fixed amount of memory
3529 ** (just an integer to hold its size) while it is being processed.
3530 ** Zeroblobs are intended to serve as placeholders for BLOBs whose
3531 ** content is later written using
3532 ** [sqlite3_blob_open | incremental BLOB I/O] routines.
3533 ** ^A negative value for the zeroblob results in a zero-length BLOB.
3535 ** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
3536 ** for the [prepared statement] or with a prepared statement for which
3537 ** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
3538 ** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_()
3539 ** routine is passed a [prepared statement] that has been finalized, the
3540 ** result is undefined and probably harmful.
3542 ** ^Bindings are not cleared by the [sqlite3_reset()] routine.
3543 ** ^Unbound parameters are interpreted as NULL.
3545 ** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
3546 ** [error code] if anything goes wrong.
3547 ** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB
3548 ** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or
3549 ** [SQLITE_MAX_LENGTH].
3550 ** ^[SQLITE_RANGE] is returned if the parameter
3551 ** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails.
3553 ** See also: [sqlite3_bind_parameter_count()],
3554 ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
3556 SQLITE_API int SQLITE_STDCALL sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
3557 SQLITE_API int SQLITE_STDCALL sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64,
3559 SQLITE_API int SQLITE_STDCALL sqlite3_bind_double(sqlite3_stmt*, int, double);
3560 SQLITE_API int SQLITE_STDCALL sqlite3_bind_int(sqlite3_stmt*, int, int);
3561 SQLITE_API int SQLITE_STDCALL sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
3562 SQLITE_API int SQLITE_STDCALL sqlite3_bind_null(sqlite3_stmt*, int);
3563 SQLITE_API int SQLITE_STDCALL sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*));
3564 SQLITE_API int SQLITE_STDCALL sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
3565 SQLITE_API int SQLITE_STDCALL sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64,
3566 void(*)(void*), unsigned char encoding);
3567 SQLITE_API int SQLITE_STDCALL sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
3568 SQLITE_API int SQLITE_STDCALL sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
3569 SQLITE_API int SQLITE_STDCALL sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64);
3572 ** CAPI3REF: Number Of SQL Parameters
3573 ** METHOD: sqlite3_stmt
3575 ** ^This routine can be used to find the number of [SQL parameters]
3576 ** in a [prepared statement]. SQL parameters are tokens of the
3577 ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
3578 ** placeholders for values that are [sqlite3_bind_blob | bound]
3579 ** to the parameters at a later time.
3581 ** ^(This routine actually returns the index of the largest (rightmost)
3582 ** parameter. For all forms except ?NNN, this will correspond to the
3583 ** number of unique parameters. If parameters of the ?NNN form are used,
3584 ** there may be gaps in the list.)^
3586 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
3587 ** [sqlite3_bind_parameter_name()], and
3588 ** [sqlite3_bind_parameter_index()].
3590 SQLITE_API int SQLITE_STDCALL sqlite3_bind_parameter_count(sqlite3_stmt*);
3593 ** CAPI3REF: Name Of A Host Parameter
3594 ** METHOD: sqlite3_stmt
3596 ** ^The sqlite3_bind_parameter_name(P,N) interface returns
3597 ** the name of the N-th [SQL parameter] in the [prepared statement] P.
3598 ** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
3599 ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
3601 ** In other words, the initial ":" or "$" or "@" or "?"
3602 ** is included as part of the name.)^
3603 ** ^Parameters of the form "?" without a following integer have no name
3604 ** and are referred to as "nameless" or "anonymous parameters".
3606 ** ^The first host parameter has an index of 1, not 0.
3608 ** ^If the value N is out of range or if the N-th parameter is
3609 ** nameless, then NULL is returned. ^The returned string is
3610 ** always in UTF-8 encoding even if the named parameter was
3611 ** originally specified as UTF-16 in [sqlite3_prepare16()] or
3612 ** [sqlite3_prepare16_v2()].
3614 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
3615 ** [sqlite3_bind_parameter_count()], and
3616 ** [sqlite3_bind_parameter_index()].
3618 SQLITE_API const char *SQLITE_STDCALL sqlite3_bind_parameter_name(sqlite3_stmt*, int);
3621 ** CAPI3REF: Index Of A Parameter With A Given Name
3622 ** METHOD: sqlite3_stmt
3624 ** ^Return the index of an SQL parameter given its name. ^The
3625 ** index value returned is suitable for use as the second
3626 ** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero
3627 ** is returned if no matching parameter is found. ^The parameter
3628 ** name must be given in UTF-8 even if the original statement
3629 ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()].
3631 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
3632 ** [sqlite3_bind_parameter_count()], and
3633 ** [sqlite3_bind_parameter_name()].
3635 SQLITE_API int SQLITE_STDCALL sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
3638 ** CAPI3REF: Reset All Bindings On A Prepared Statement
3639 ** METHOD: sqlite3_stmt
3641 ** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
3642 ** the [sqlite3_bind_blob | bindings] on a [prepared statement].
3643 ** ^Use this routine to reset all host parameters to NULL.
3645 SQLITE_API int SQLITE_STDCALL sqlite3_clear_bindings(sqlite3_stmt*);
3648 ** CAPI3REF: Number Of Columns In A Result Set
3649 ** METHOD: sqlite3_stmt
3651 ** ^Return the number of columns in the result set returned by the
3652 ** [prepared statement]. ^This routine returns 0 if pStmt is an SQL
3653 ** statement that does not return data (for example an [UPDATE]).
3655 ** See also: [sqlite3_data_count()]
3657 SQLITE_API int SQLITE_STDCALL sqlite3_column_count(sqlite3_stmt *pStmt);
3660 ** CAPI3REF: Column Names In A Result Set
3661 ** METHOD: sqlite3_stmt
3663 ** ^These routines return the name assigned to a particular column
3664 ** in the result set of a [SELECT] statement. ^The sqlite3_column_name()
3665 ** interface returns a pointer to a zero-terminated UTF-8 string
3666 ** and sqlite3_column_name16() returns a pointer to a zero-terminated
3667 ** UTF-16 string. ^The first parameter is the [prepared statement]
3668 ** that implements the [SELECT] statement. ^The second parameter is the
3669 ** column number. ^The leftmost column is number 0.
3671 ** ^The returned string pointer is valid until either the [prepared statement]
3672 ** is destroyed by [sqlite3_finalize()] or until the statement is automatically
3673 ** reprepared by the first call to [sqlite3_step()] for a particular run
3674 ** or until the next call to
3675 ** sqlite3_column_name() or sqlite3_column_name16() on the same column.
3677 ** ^If sqlite3_malloc() fails during the processing of either routine
3678 ** (for example during a conversion from UTF-8 to UTF-16) then a
3679 ** NULL pointer is returned.
3681 ** ^The name of a result column is the value of the "AS" clause for
3682 ** that column, if there is an AS clause. If there is no AS clause
3683 ** then the name of the column is unspecified and may change from
3684 ** one release of SQLite to the next.
3686 SQLITE_API const char *SQLITE_STDCALL sqlite3_column_name(sqlite3_stmt*, int N);
3687 SQLITE_API const void *SQLITE_STDCALL sqlite3_column_name16(sqlite3_stmt*, int N);
3690 ** CAPI3REF: Source Of Data In A Query Result
3691 ** METHOD: sqlite3_stmt
3693 ** ^These routines provide a means to determine the database, table, and
3694 ** table column that is the origin of a particular result column in
3695 ** [SELECT] statement.
3696 ** ^The name of the database or table or column can be returned as
3697 ** either a UTF-8 or UTF-16 string. ^The _database_ routines return
3698 ** the database name, the _table_ routines return the table name, and
3699 ** the origin_ routines return the column name.
3700 ** ^The returned string is valid until the [prepared statement] is destroyed
3701 ** using [sqlite3_finalize()] or until the statement is automatically
3702 ** reprepared by the first call to [sqlite3_step()] for a particular run
3703 ** or until the same information is requested
3704 ** again in a different encoding.
3706 ** ^The names returned are the original un-aliased names of the
3707 ** database, table, and column.
3709 ** ^The first argument to these interfaces is a [prepared statement].
3710 ** ^These functions return information about the Nth result column returned by
3711 ** the statement, where N is the second function argument.
3712 ** ^The left-most column is column 0 for these routines.
3714 ** ^If the Nth column returned by the statement is an expression or
3715 ** subquery and is not a column value, then all of these functions return
3716 ** NULL. ^These routine might also return NULL if a memory allocation error
3717 ** occurs. ^Otherwise, they return the name of the attached database, table,
3718 ** or column that query result column was extracted from.
3720 ** ^As with all other SQLite APIs, those whose names end with "16" return
3721 ** UTF-16 encoded strings and the other functions return UTF-8.
3723 ** ^These APIs are only available if the library was compiled with the
3724 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
3726 ** If two or more threads call one or more of these routines against the same
3727 ** prepared statement and column at the same time then the results are
3730 ** If two or more threads call one or more
3731 ** [sqlite3_column_database_name | column metadata interfaces]
3732 ** for the same [prepared statement] and result column
3733 ** at the same time then the results are undefined.
3735 SQLITE_API const char *SQLITE_STDCALL sqlite3_column_database_name(sqlite3_stmt*,int);
3736 SQLITE_API const void *SQLITE_STDCALL sqlite3_column_database_name16(sqlite3_stmt*,int);
3737 SQLITE_API const char *SQLITE_STDCALL sqlite3_column_table_name(sqlite3_stmt*,int);
3738 SQLITE_API const void *SQLITE_STDCALL sqlite3_column_table_name16(sqlite3_stmt*,int);
3739 SQLITE_API const char *SQLITE_STDCALL sqlite3_column_origin_name(sqlite3_stmt*,int);
3740 SQLITE_API const void *SQLITE_STDCALL sqlite3_column_origin_name16(sqlite3_stmt*,int);
3743 ** CAPI3REF: Declared Datatype Of A Query Result
3744 ** METHOD: sqlite3_stmt
3746 ** ^(The first parameter is a [prepared statement].
3747 ** If this statement is a [SELECT] statement and the Nth column of the
3748 ** returned result set of that [SELECT] is a table column (not an
3749 ** expression or subquery) then the declared type of the table
3750 ** column is returned.)^ ^If the Nth column of the result set is an
3751 ** expression or subquery, then a NULL pointer is returned.
3752 ** ^The returned string is always UTF-8 encoded.
3754 ** ^(For example, given the database schema:
3756 ** CREATE TABLE t1(c1 VARIANT);
3758 ** and the following statement to be compiled:
3760 ** SELECT c1 + 1, c1 FROM t1;
3762 ** this routine would return the string "VARIANT" for the second result
3763 ** column (i==1), and a NULL pointer for the first result column (i==0).)^
3765 ** ^SQLite uses dynamic run-time typing. ^So just because a column
3766 ** is declared to contain a particular type does not mean that the
3767 ** data stored in that column is of the declared type. SQLite is
3768 ** strongly typed, but the typing is dynamic not static. ^Type
3769 ** is associated with individual values, not with the containers
3770 ** used to hold those values.
3772 SQLITE_API const char *SQLITE_STDCALL sqlite3_column_decltype(sqlite3_stmt*,int);
3773 SQLITE_API const void *SQLITE_STDCALL sqlite3_column_decltype16(sqlite3_stmt*,int);
3776 ** CAPI3REF: Evaluate An SQL Statement
3777 ** METHOD: sqlite3_stmt
3779 ** After a [prepared statement] has been prepared using either
3780 ** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy
3781 ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
3782 ** must be called one or more times to evaluate the statement.
3784 ** The details of the behavior of the sqlite3_step() interface depend
3785 ** on whether the statement was prepared using the newer "v2" interface
3786 ** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy
3787 ** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the
3788 ** new "v2" interface is recommended for new applications but the legacy
3789 ** interface will continue to be supported.
3791 ** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
3792 ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
3793 ** ^With the "v2" interface, any of the other [result codes] or
3794 ** [extended result codes] might be returned as well.
3796 ** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
3797 ** database locks it needs to do its job. ^If the statement is a [COMMIT]
3798 ** or occurs outside of an explicit transaction, then you can retry the
3799 ** statement. If the statement is not a [COMMIT] and occurs within an
3800 ** explicit transaction then you should rollback the transaction before
3803 ** ^[SQLITE_DONE] means that the statement has finished executing
3804 ** successfully. sqlite3_step() should not be called again on this virtual
3805 ** machine without first calling [sqlite3_reset()] to reset the virtual
3806 ** machine back to its initial state.
3808 ** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
3809 ** is returned each time a new row of data is ready for processing by the
3810 ** caller. The values may be accessed using the [column access functions].
3811 ** sqlite3_step() is called again to retrieve the next row of data.
3813 ** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
3814 ** violation) has occurred. sqlite3_step() should not be called again on
3815 ** the VM. More information may be found by calling [sqlite3_errmsg()].
3816 ** ^With the legacy interface, a more specific error code (for example,
3817 ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
3818 ** can be obtained by calling [sqlite3_reset()] on the
3819 ** [prepared statement]. ^In the "v2" interface,
3820 ** the more specific error code is returned directly by sqlite3_step().
3822 ** [SQLITE_MISUSE] means that the this routine was called inappropriately.
3823 ** Perhaps it was called on a [prepared statement] that has
3824 ** already been [sqlite3_finalize | finalized] or on one that had
3825 ** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could
3826 ** be the case that the same database connection is being used by two or
3827 ** more threads at the same moment in time.
3829 ** For all versions of SQLite up to and including 3.6.23.1, a call to
3830 ** [sqlite3_reset()] was required after sqlite3_step() returned anything
3831 ** other than [SQLITE_ROW] before any subsequent invocation of
3832 ** sqlite3_step(). Failure to reset the prepared statement using
3833 ** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
3834 ** sqlite3_step(). But after version 3.6.23.1, sqlite3_step() began
3835 ** calling [sqlite3_reset()] automatically in this circumstance rather
3836 ** than returning [SQLITE_MISUSE]. This is not considered a compatibility
3837 ** break because any application that ever receives an SQLITE_MISUSE error
3838 ** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option
3839 ** can be used to restore the legacy behavior.
3841 ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
3842 ** API always returns a generic error code, [SQLITE_ERROR], following any
3843 ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call
3844 ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
3845 ** specific [error codes] that better describes the error.
3846 ** We admit that this is a goofy design. The problem has been fixed
3847 ** with the "v2" interface. If you prepare all of your SQL statements
3848 ** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead
3849 ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
3850 ** then the more specific [error codes] are returned directly
3851 ** by sqlite3_step(). The use of the "v2" interface is recommended.
3853 SQLITE_API int SQLITE_STDCALL sqlite3_step(sqlite3_stmt*);
3856 ** CAPI3REF: Number of columns in a result set
3857 ** METHOD: sqlite3_stmt
3859 ** ^The sqlite3_data_count(P) interface returns the number of columns in the
3860 ** current row of the result set of [prepared statement] P.
3861 ** ^If prepared statement P does not have results ready to return
3862 ** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of
3863 ** interfaces) then sqlite3_data_count(P) returns 0.
3864 ** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
3865 ** ^The sqlite3_data_count(P) routine returns 0 if the previous call to
3866 ** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P)
3867 ** will return non-zero if previous call to [sqlite3_step](P) returned
3868 ** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum]
3869 ** where it always returns zero since each step of that multi-step
3870 ** pragma returns 0 columns of data.
3872 ** See also: [sqlite3_column_count()]
3874 SQLITE_API int SQLITE_STDCALL sqlite3_data_count(sqlite3_stmt *pStmt);
3877 ** CAPI3REF: Fundamental Datatypes
3878 ** KEYWORDS: SQLITE_TEXT
3880 ** ^(Every value in SQLite has one of five fundamental datatypes:
3883 ** <li> 64-bit signed integer
3884 ** <li> 64-bit IEEE floating point number
3890 ** These constants are codes for each of those types.
3892 ** Note that the SQLITE_TEXT constant was also used in SQLite version 2
3893 ** for a completely different meaning. Software that links against both
3894 ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
3897 #define SQLITE_INTEGER 1
3898 #define SQLITE_FLOAT 2
3899 #define SQLITE_BLOB 4
3900 #define SQLITE_NULL 5
3904 # define SQLITE_TEXT 3
3906 #define SQLITE3_TEXT 3
3909 ** CAPI3REF: Result Values From A Query
3910 ** KEYWORDS: {column access functions}
3911 ** METHOD: sqlite3_stmt
3913 ** ^These routines return information about a single column of the current
3914 ** result row of a query. ^In every case the first argument is a pointer
3915 ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
3916 ** that was returned from [sqlite3_prepare_v2()] or one of its variants)
3917 ** and the second argument is the index of the column for which information
3918 ** should be returned. ^The leftmost column of the result set has the index 0.
3919 ** ^The number of columns in the result can be determined using
3920 ** [sqlite3_column_count()].
3922 ** If the SQL statement does not currently point to a valid row, or if the
3923 ** column index is out of range, the result is undefined.
3924 ** These routines may only be called when the most recent call to
3925 ** [sqlite3_step()] has returned [SQLITE_ROW] and neither
3926 ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
3927 ** If any of these routines are called after [sqlite3_reset()] or
3928 ** [sqlite3_finalize()] or after [sqlite3_step()] has returned
3929 ** something other than [SQLITE_ROW], the results are undefined.
3930 ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
3931 ** are called from a different thread while any of these routines
3932 ** are pending, then the results are undefined.
3934 ** ^The sqlite3_column_type() routine returns the
3935 ** [SQLITE_INTEGER | datatype code] for the initial data type
3936 ** of the result column. ^The returned value is one of [SQLITE_INTEGER],
3937 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value
3938 ** returned by sqlite3_column_type() is only meaningful if no type
3939 ** conversions have occurred as described below. After a type conversion,
3940 ** the value returned by sqlite3_column_type() is undefined. Future
3941 ** versions of SQLite may change the behavior of sqlite3_column_type()
3942 ** following a type conversion.
3944 ** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
3945 ** routine returns the number of bytes in that BLOB or string.
3946 ** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
3947 ** the string to UTF-8 and then returns the number of bytes.
3948 ** ^If the result is a numeric value then sqlite3_column_bytes() uses
3949 ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
3950 ** the number of bytes in that string.
3951 ** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
3953 ** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
3954 ** routine returns the number of bytes in that BLOB or string.
3955 ** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
3956 ** the string to UTF-16 and then returns the number of bytes.
3957 ** ^If the result is a numeric value then sqlite3_column_bytes16() uses
3958 ** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
3959 ** the number of bytes in that string.
3960 ** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
3962 ** ^The values returned by [sqlite3_column_bytes()] and
3963 ** [sqlite3_column_bytes16()] do not include the zero terminators at the end
3964 ** of the string. ^For clarity: the values returned by
3965 ** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
3966 ** bytes in the string, not the number of characters.
3968 ** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
3969 ** even empty strings, are always zero-terminated. ^The return
3970 ** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
3972 ** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an
3973 ** [unprotected sqlite3_value] object. In a multithreaded environment,
3974 ** an unprotected sqlite3_value object may only be used safely with
3975 ** [sqlite3_bind_value()] and [sqlite3_result_value()].
3976 ** If the [unprotected sqlite3_value] object returned by
3977 ** [sqlite3_column_value()] is used in any other way, including calls
3978 ** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
3979 ** or [sqlite3_value_bytes()], the behavior is not threadsafe.
3981 ** These routines attempt to convert the value where appropriate. ^For
3982 ** example, if the internal representation is FLOAT and a text result
3983 ** is requested, [sqlite3_snprintf()] is used internally to perform the
3984 ** conversion automatically. ^(The following table details the conversions
3985 ** that are applied:
3988 ** <table border="1">
3989 ** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion
3991 ** <tr><td> NULL <td> INTEGER <td> Result is 0
3992 ** <tr><td> NULL <td> FLOAT <td> Result is 0.0
3993 ** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer
3994 ** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer
3995 ** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float
3996 ** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer
3997 ** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT
3998 ** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER
3999 ** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float
4000 ** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB
4001 ** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER
4002 ** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL
4003 ** <tr><td> TEXT <td> BLOB <td> No change
4004 ** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER
4005 ** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL
4006 ** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed
4010 ** Note that when type conversions occur, pointers returned by prior
4011 ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
4012 ** sqlite3_column_text16() may be invalidated.
4013 ** Type conversions and pointer invalidations might occur
4014 ** in the following cases:
4017 ** <li> The initial content is a BLOB and sqlite3_column_text() or
4018 ** sqlite3_column_text16() is called. A zero-terminator might
4019 ** need to be added to the string.</li>
4020 ** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
4021 ** sqlite3_column_text16() is called. The content must be converted
4023 ** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
4024 ** sqlite3_column_text() is called. The content must be converted
4028 ** ^Conversions between UTF-16be and UTF-16le are always done in place and do
4029 ** not invalidate a prior pointer, though of course the content of the buffer
4030 ** that the prior pointer references will have been modified. Other kinds
4031 ** of conversion are done in place when it is possible, but sometimes they
4032 ** are not possible and in those cases prior pointers are invalidated.
4034 ** The safest policy is to invoke these routines
4035 ** in one of the following ways:
4038 ** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
4039 ** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
4040 ** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
4043 ** In other words, you should call sqlite3_column_text(),
4044 ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
4045 ** into the desired format, then invoke sqlite3_column_bytes() or
4046 ** sqlite3_column_bytes16() to find the size of the result. Do not mix calls
4047 ** to sqlite3_column_text() or sqlite3_column_blob() with calls to
4048 ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
4049 ** with calls to sqlite3_column_bytes().
4051 ** ^The pointers returned are valid until a type conversion occurs as
4052 ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
4053 ** [sqlite3_finalize()] is called. ^The memory space used to hold strings
4054 ** and BLOBs is freed automatically. Do <em>not</em> pass the pointers returned
4055 ** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
4056 ** [sqlite3_free()].
4058 ** ^(If a memory allocation error occurs during the evaluation of any
4059 ** of these routines, a default value is returned. The default value
4060 ** is either the integer 0, the floating point number 0.0, or a NULL
4061 ** pointer. Subsequent calls to [sqlite3_errcode()] will return
4062 ** [SQLITE_NOMEM].)^
4064 SQLITE_API const void *SQLITE_STDCALL sqlite3_column_blob(sqlite3_stmt*, int iCol);
4065 SQLITE_API int SQLITE_STDCALL sqlite3_column_bytes(sqlite3_stmt*, int iCol);
4066 SQLITE_API int SQLITE_STDCALL sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
4067 SQLITE_API double SQLITE_STDCALL sqlite3_column_double(sqlite3_stmt*, int iCol);
4068 SQLITE_API int SQLITE_STDCALL sqlite3_column_int(sqlite3_stmt*, int iCol);
4069 SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_column_int64(sqlite3_stmt*, int iCol);
4070 SQLITE_API const unsigned char *SQLITE_STDCALL sqlite3_column_text(sqlite3_stmt*, int iCol);
4071 SQLITE_API const void *SQLITE_STDCALL sqlite3_column_text16(sqlite3_stmt*, int iCol);
4072 SQLITE_API int SQLITE_STDCALL sqlite3_column_type(sqlite3_stmt*, int iCol);
4073 SQLITE_API sqlite3_value *SQLITE_STDCALL sqlite3_column_value(sqlite3_stmt*, int iCol);
4076 ** CAPI3REF: Destroy A Prepared Statement Object
4077 ** DESTRUCTOR: sqlite3_stmt
4079 ** ^The sqlite3_finalize() function is called to delete a [prepared statement].
4080 ** ^If the most recent evaluation of the statement encountered no errors
4081 ** or if the statement is never been evaluated, then sqlite3_finalize() returns
4082 ** SQLITE_OK. ^If the most recent evaluation of statement S failed, then
4083 ** sqlite3_finalize(S) returns the appropriate [error code] or
4084 ** [extended error code].
4086 ** ^The sqlite3_finalize(S) routine can be called at any point during
4087 ** the life cycle of [prepared statement] S:
4088 ** before statement S is ever evaluated, after
4089 ** one or more calls to [sqlite3_reset()], or after any call
4090 ** to [sqlite3_step()] regardless of whether or not the statement has
4091 ** completed execution.
4093 ** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
4095 ** The application must finalize every [prepared statement] in order to avoid
4096 ** resource leaks. It is a grievous error for the application to try to use
4097 ** a prepared statement after it has been finalized. Any use of a prepared
4098 ** statement after it has been finalized can result in undefined and
4099 ** undesirable behavior such as segfaults and heap corruption.
4101 SQLITE_API int SQLITE_STDCALL sqlite3_finalize(sqlite3_stmt *pStmt);
4104 ** CAPI3REF: Reset A Prepared Statement Object
4105 ** METHOD: sqlite3_stmt
4107 ** The sqlite3_reset() function is called to reset a [prepared statement]
4108 ** object back to its initial state, ready to be re-executed.
4109 ** ^Any SQL statement variables that had values bound to them using
4110 ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
4111 ** Use [sqlite3_clear_bindings()] to reset the bindings.
4113 ** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
4114 ** back to the beginning of its program.
4116 ** ^If the most recent call to [sqlite3_step(S)] for the
4117 ** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
4118 ** or if [sqlite3_step(S)] has never before been called on S,
4119 ** then [sqlite3_reset(S)] returns [SQLITE_OK].
4121 ** ^If the most recent call to [sqlite3_step(S)] for the
4122 ** [prepared statement] S indicated an error, then
4123 ** [sqlite3_reset(S)] returns an appropriate [error code].
4125 ** ^The [sqlite3_reset(S)] interface does not change the values
4126 ** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
4128 SQLITE_API int SQLITE_STDCALL sqlite3_reset(sqlite3_stmt *pStmt);
4131 ** CAPI3REF: Create Or Redefine SQL Functions
4132 ** KEYWORDS: {function creation routines}
4133 ** KEYWORDS: {application-defined SQL function}
4134 ** KEYWORDS: {application-defined SQL functions}
4137 ** ^These functions (collectively known as "function creation routines")
4138 ** are used to add SQL functions or aggregates or to redefine the behavior
4139 ** of existing SQL functions or aggregates. The only differences between
4140 ** these routines are the text encoding expected for
4141 ** the second parameter (the name of the function being created)
4142 ** and the presence or absence of a destructor callback for
4143 ** the application data pointer.
4145 ** ^The first parameter is the [database connection] to which the SQL
4146 ** function is to be added. ^If an application uses more than one database
4147 ** connection then application-defined SQL functions must be added
4148 ** to each database connection separately.
4150 ** ^The second parameter is the name of the SQL function to be created or
4151 ** redefined. ^The length of the name is limited to 255 bytes in a UTF-8
4152 ** representation, exclusive of the zero-terminator. ^Note that the name
4153 ** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
4154 ** ^Any attempt to create a function with a longer name
4155 ** will result in [SQLITE_MISUSE] being returned.
4157 ** ^The third parameter (nArg)
4158 ** is the number of arguments that the SQL function or
4159 ** aggregate takes. ^If this parameter is -1, then the SQL function or
4160 ** aggregate may take any number of arguments between 0 and the limit
4161 ** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third
4162 ** parameter is less than -1 or greater than 127 then the behavior is
4165 ** ^The fourth parameter, eTextRep, specifies what
4166 ** [SQLITE_UTF8 | text encoding] this SQL function prefers for
4167 ** its parameters. The application should set this parameter to
4168 ** [SQLITE_UTF16LE] if the function implementation invokes
4169 ** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the
4170 ** implementation invokes [sqlite3_value_text16be()] on an input, or
4171 ** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8]
4172 ** otherwise. ^The same SQL function may be registered multiple times using
4173 ** different preferred text encodings, with different implementations for
4175 ** ^When multiple implementations of the same function are available, SQLite
4176 ** will pick the one that involves the least amount of data conversion.
4178 ** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC]
4179 ** to signal that the function will always return the same result given
4180 ** the same inputs within a single SQL statement. Most SQL functions are
4181 ** deterministic. The built-in [random()] SQL function is an example of a
4182 ** function that is not deterministic. The SQLite query planner is able to
4183 ** perform additional optimizations on deterministic functions, so use
4184 ** of the [SQLITE_DETERMINISTIC] flag is recommended where possible.
4186 ** ^(The fifth parameter is an arbitrary pointer. The implementation of the
4187 ** function can gain access to this pointer using [sqlite3_user_data()].)^
4189 ** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are
4190 ** pointers to C-language functions that implement the SQL function or
4191 ** aggregate. ^A scalar SQL function requires an implementation of the xFunc
4192 ** callback only; NULL pointers must be passed as the xStep and xFinal
4193 ** parameters. ^An aggregate SQL function requires an implementation of xStep
4194 ** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
4195 ** SQL function or aggregate, pass NULL pointers for all three function
4198 ** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL,
4199 ** then it is destructor for the application data pointer.
4200 ** The destructor is invoked when the function is deleted, either by being
4201 ** overloaded or when the database connection closes.)^
4202 ** ^The destructor is also invoked if the call to
4203 ** sqlite3_create_function_v2() fails.
4204 ** ^When the destructor callback of the tenth parameter is invoked, it
4205 ** is passed a single argument which is a copy of the application data
4206 ** pointer which was the fifth parameter to sqlite3_create_function_v2().
4208 ** ^It is permitted to register multiple implementations of the same
4209 ** functions with the same name but with either differing numbers of
4210 ** arguments or differing preferred text encodings. ^SQLite will use
4211 ** the implementation that most closely matches the way in which the
4212 ** SQL function is used. ^A function implementation with a non-negative
4213 ** nArg parameter is a better match than a function implementation with
4214 ** a negative nArg. ^A function where the preferred text encoding
4215 ** matches the database encoding is a better
4216 ** match than a function where the encoding is different.
4217 ** ^A function where the encoding difference is between UTF16le and UTF16be
4218 ** is a closer match than a function where the encoding difference is
4219 ** between UTF8 and UTF16.
4221 ** ^Built-in functions may be overloaded by new application-defined functions.
4223 ** ^An application-defined function is permitted to call other
4224 ** SQLite interfaces. However, such calls must not
4225 ** close the database connection nor finalize or reset the prepared
4226 ** statement in which the function is running.
4228 SQLITE_API int SQLITE_STDCALL sqlite3_create_function(
4230 const char *zFunctionName,
4234 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4235 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4236 void (*xFinal)(sqlite3_context*)
4238 SQLITE_API int SQLITE_STDCALL sqlite3_create_function16(
4240 const void *zFunctionName,
4244 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4245 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4246 void (*xFinal)(sqlite3_context*)
4248 SQLITE_API int SQLITE_STDCALL sqlite3_create_function_v2(
4250 const char *zFunctionName,
4254 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4255 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4256 void (*xFinal)(sqlite3_context*),
4257 void(*xDestroy)(void*)
4261 ** CAPI3REF: Text Encodings
4263 ** These constant define integer codes that represent the various
4264 ** text encodings supported by SQLite.
4266 #define SQLITE_UTF8 1 /* IMP: R-37514-35566 */
4267 #define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */
4268 #define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */
4269 #define SQLITE_UTF16 4 /* Use native byte order */
4270 #define SQLITE_ANY 5 /* Deprecated */
4271 #define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */
4274 ** CAPI3REF: Function Flags
4276 ** These constants may be ORed together with the
4277 ** [SQLITE_UTF8 | preferred text encoding] as the fourth argument
4278 ** to [sqlite3_create_function()], [sqlite3_create_function16()], or
4279 ** [sqlite3_create_function_v2()].
4281 #define SQLITE_DETERMINISTIC 0x800
4284 ** CAPI3REF: Deprecated Functions
4287 ** These functions are [deprecated]. In order to maintain
4288 ** backwards compatibility with older code, these functions continue
4289 ** to be supported. However, new applications should avoid
4290 ** the use of these functions. To encourage programmers to avoid
4291 ** these functions, we will not explain what they do.
4293 #ifndef SQLITE_OMIT_DEPRECATED
4294 SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_aggregate_count(sqlite3_context*);
4295 SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_expired(sqlite3_stmt*);
4296 SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
4297 SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_global_recover(void);
4298 SQLITE_API SQLITE_DEPRECATED void SQLITE_STDCALL sqlite3_thread_cleanup(void);
4299 SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),
4300 void*,sqlite3_int64);
4304 ** CAPI3REF: Obtaining SQL Values
4305 ** METHOD: sqlite3_value
4307 ** The C-language implementation of SQL functions and aggregates uses
4308 ** this set of interface routines to access the parameter values on
4309 ** the function or aggregate.
4311 ** The xFunc (for scalar functions) or xStep (for aggregates) parameters
4312 ** to [sqlite3_create_function()] and [sqlite3_create_function16()]
4313 ** define callbacks that implement the SQL functions and aggregates.
4314 ** The 3rd parameter to these callbacks is an array of pointers to
4315 ** [protected sqlite3_value] objects. There is one [sqlite3_value] object for
4316 ** each parameter to the SQL function. These routines are used to
4317 ** extract values from the [sqlite3_value] objects.
4319 ** These routines work only with [protected sqlite3_value] objects.
4320 ** Any attempt to use these routines on an [unprotected sqlite3_value]
4321 ** object results in undefined behavior.
4323 ** ^These routines work just like the corresponding [column access functions]
4324 ** except that these routines take a single [protected sqlite3_value] object
4325 ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
4327 ** ^The sqlite3_value_text16() interface extracts a UTF-16 string
4328 ** in the native byte-order of the host machine. ^The
4329 ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
4330 ** extract UTF-16 strings as big-endian and little-endian respectively.
4332 ** ^(The sqlite3_value_numeric_type() interface attempts to apply
4333 ** numeric affinity to the value. This means that an attempt is
4334 ** made to convert the value to an integer or floating point. If
4335 ** such a conversion is possible without loss of information (in other
4336 ** words, if the value is a string that looks like a number)
4337 ** then the conversion is performed. Otherwise no conversion occurs.
4338 ** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
4340 ** Please pay particular attention to the fact that the pointer returned
4341 ** from [sqlite3_value_blob()], [sqlite3_value_text()], or
4342 ** [sqlite3_value_text16()] can be invalidated by a subsequent call to
4343 ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
4344 ** or [sqlite3_value_text16()].
4346 ** These routines must be called from the same thread as
4347 ** the SQL function that supplied the [sqlite3_value*] parameters.
4349 SQLITE_API const void *SQLITE_STDCALL sqlite3_value_blob(sqlite3_value*);
4350 SQLITE_API int SQLITE_STDCALL sqlite3_value_bytes(sqlite3_value*);
4351 SQLITE_API int SQLITE_STDCALL sqlite3_value_bytes16(sqlite3_value*);
4352 SQLITE_API double SQLITE_STDCALL sqlite3_value_double(sqlite3_value*);
4353 SQLITE_API int SQLITE_STDCALL sqlite3_value_int(sqlite3_value*);
4354 SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_value_int64(sqlite3_value*);
4355 SQLITE_API const unsigned char *SQLITE_STDCALL sqlite3_value_text(sqlite3_value*);
4356 SQLITE_API const void *SQLITE_STDCALL sqlite3_value_text16(sqlite3_value*);
4357 SQLITE_API const void *SQLITE_STDCALL sqlite3_value_text16le(sqlite3_value*);
4358 SQLITE_API const void *SQLITE_STDCALL sqlite3_value_text16be(sqlite3_value*);
4359 SQLITE_API int SQLITE_STDCALL sqlite3_value_type(sqlite3_value*);
4360 SQLITE_API int SQLITE_STDCALL sqlite3_value_numeric_type(sqlite3_value*);
4363 ** CAPI3REF: Finding The Subtype Of SQL Values
4364 ** METHOD: sqlite3_value
4366 ** The sqlite3_value_subtype(V) function returns the subtype for
4367 ** an [application-defined SQL function] argument V. The subtype
4368 ** information can be used to pass a limited amount of context from
4369 ** one SQL function to another. Use the [sqlite3_result_subtype()]
4370 ** routine to set the subtype for the return value of an SQL function.
4372 ** SQLite makes no use of subtype itself. It merely passes the subtype
4373 ** from the result of one [application-defined SQL function] into the
4374 ** input of another.
4376 SQLITE_API unsigned int SQLITE_STDCALL sqlite3_value_subtype(sqlite3_value*);
4379 ** CAPI3REF: Copy And Free SQL Values
4380 ** METHOD: sqlite3_value
4382 ** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value]
4383 ** object D and returns a pointer to that copy. ^The [sqlite3_value] returned
4384 ** is a [protected sqlite3_value] object even if the input is not.
4385 ** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a
4386 ** memory allocation fails.
4388 ** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object
4389 ** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer
4390 ** then sqlite3_value_free(V) is a harmless no-op.
4392 SQLITE_API SQLITE_EXPERIMENTAL sqlite3_value *SQLITE_STDCALL sqlite3_value_dup(const sqlite3_value*);
4393 SQLITE_API SQLITE_EXPERIMENTAL void SQLITE_STDCALL sqlite3_value_free(sqlite3_value*);
4396 ** CAPI3REF: Obtain Aggregate Function Context
4397 ** METHOD: sqlite3_context
4399 ** Implementations of aggregate SQL functions use this
4400 ** routine to allocate memory for storing their state.
4402 ** ^The first time the sqlite3_aggregate_context(C,N) routine is called
4403 ** for a particular aggregate function, SQLite
4404 ** allocates N of memory, zeroes out that memory, and returns a pointer
4405 ** to the new memory. ^On second and subsequent calls to
4406 ** sqlite3_aggregate_context() for the same aggregate function instance,
4407 ** the same buffer is returned. Sqlite3_aggregate_context() is normally
4408 ** called once for each invocation of the xStep callback and then one
4409 ** last time when the xFinal callback is invoked. ^(When no rows match
4410 ** an aggregate query, the xStep() callback of the aggregate function
4411 ** implementation is never called and xFinal() is called exactly once.
4412 ** In those cases, sqlite3_aggregate_context() might be called for the
4413 ** first time from within xFinal().)^
4415 ** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer
4416 ** when first called if N is less than or equal to zero or if a memory
4417 ** allocate error occurs.
4419 ** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
4420 ** determined by the N parameter on first successful call. Changing the
4421 ** value of N in subsequent call to sqlite3_aggregate_context() within
4422 ** the same aggregate function instance will not resize the memory
4423 ** allocation.)^ Within the xFinal callback, it is customary to set
4424 ** N=0 in calls to sqlite3_aggregate_context(C,N) so that no
4425 ** pointless memory allocations occur.
4427 ** ^SQLite automatically frees the memory allocated by
4428 ** sqlite3_aggregate_context() when the aggregate query concludes.
4430 ** The first parameter must be a copy of the
4431 ** [sqlite3_context | SQL function context] that is the first parameter
4432 ** to the xStep or xFinal callback routine that implements the aggregate
4435 ** This routine must be called from the same thread in which
4436 ** the aggregate SQL function is running.
4438 SQLITE_API void *SQLITE_STDCALL sqlite3_aggregate_context(sqlite3_context*, int nBytes);
4441 ** CAPI3REF: User Data For Functions
4442 ** METHOD: sqlite3_context
4444 ** ^The sqlite3_user_data() interface returns a copy of
4445 ** the pointer that was the pUserData parameter (the 5th parameter)
4446 ** of the [sqlite3_create_function()]
4447 ** and [sqlite3_create_function16()] routines that originally
4448 ** registered the application defined function.
4450 ** This routine must be called from the same thread in which
4451 ** the application-defined function is running.
4453 SQLITE_API void *SQLITE_STDCALL sqlite3_user_data(sqlite3_context*);
4456 ** CAPI3REF: Database Connection For Functions
4457 ** METHOD: sqlite3_context
4459 ** ^The sqlite3_context_db_handle() interface returns a copy of
4460 ** the pointer to the [database connection] (the 1st parameter)
4461 ** of the [sqlite3_create_function()]
4462 ** and [sqlite3_create_function16()] routines that originally
4463 ** registered the application defined function.
4465 SQLITE_API sqlite3 *SQLITE_STDCALL sqlite3_context_db_handle(sqlite3_context*);
4468 ** CAPI3REF: Function Auxiliary Data
4469 ** METHOD: sqlite3_context
4471 ** These functions may be used by (non-aggregate) SQL functions to
4472 ** associate metadata with argument values. If the same value is passed to
4473 ** multiple invocations of the same SQL function during query execution, under
4474 ** some circumstances the associated metadata may be preserved. An example
4475 ** of where this might be useful is in a regular-expression matching
4476 ** function. The compiled version of the regular expression can be stored as
4477 ** metadata associated with the pattern string.
4478 ** Then as long as the pattern string remains the same,
4479 ** the compiled regular expression can be reused on multiple
4480 ** invocations of the same function.
4482 ** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata
4483 ** associated by the sqlite3_set_auxdata() function with the Nth argument
4484 ** value to the application-defined function. ^If there is no metadata
4485 ** associated with the function argument, this sqlite3_get_auxdata() interface
4486 ** returns a NULL pointer.
4488 ** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th
4489 ** argument of the application-defined function. ^Subsequent
4490 ** calls to sqlite3_get_auxdata(C,N) return P from the most recent
4491 ** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or
4492 ** NULL if the metadata has been discarded.
4493 ** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL,
4494 ** SQLite will invoke the destructor function X with parameter P exactly
4495 ** once, when the metadata is discarded.
4496 ** SQLite is free to discard the metadata at any time, including: <ul>
4497 ** <li> when the corresponding function parameter changes, or
4498 ** <li> when [sqlite3_reset()] or [sqlite3_finalize()] is called for the
4499 ** SQL statement, or
4500 ** <li> when sqlite3_set_auxdata() is invoked again on the same parameter, or
4501 ** <li> during the original sqlite3_set_auxdata() call when a memory
4502 ** allocation error occurs. </ul>)^
4504 ** Note the last bullet in particular. The destructor X in
4505 ** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the
4506 ** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata()
4507 ** should be called near the end of the function implementation and the
4508 ** function implementation should not make any use of P after
4509 ** sqlite3_set_auxdata() has been called.
4511 ** ^(In practice, metadata is preserved between function calls for
4512 ** function parameters that are compile-time constants, including literal
4513 ** values and [parameters] and expressions composed from the same.)^
4515 ** These routines must be called from the same thread in which
4516 ** the SQL function is running.
4518 SQLITE_API void *SQLITE_STDCALL sqlite3_get_auxdata(sqlite3_context*, int N);
4519 SQLITE_API void SQLITE_STDCALL sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
4523 ** CAPI3REF: Constants Defining Special Destructor Behavior
4525 ** These are special values for the destructor that is passed in as the
4526 ** final argument to routines like [sqlite3_result_blob()]. ^If the destructor
4527 ** argument is SQLITE_STATIC, it means that the content pointer is constant
4528 ** and will never change. It does not need to be destroyed. ^The
4529 ** SQLITE_TRANSIENT value means that the content will likely change in
4530 ** the near future and that SQLite should make its own private copy of
4531 ** the content before returning.
4533 ** The typedef is necessary to work around problems in certain
4536 typedef void (*sqlite3_destructor_type)(void*);
4537 #define SQLITE_STATIC ((sqlite3_destructor_type)0)
4538 #define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1)
4541 ** CAPI3REF: Setting The Result Of An SQL Function
4542 ** METHOD: sqlite3_context
4544 ** These routines are used by the xFunc or xFinal callbacks that
4545 ** implement SQL functions and aggregates. See
4546 ** [sqlite3_create_function()] and [sqlite3_create_function16()]
4547 ** for additional information.
4549 ** These functions work very much like the [parameter binding] family of
4550 ** functions used to bind values to host parameters in prepared statements.
4551 ** Refer to the [SQL parameter] documentation for additional information.
4553 ** ^The sqlite3_result_blob() interface sets the result from
4554 ** an application-defined function to be the BLOB whose content is pointed
4555 ** to by the second parameter and which is N bytes long where N is the
4558 ** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N)
4559 ** interfaces set the result of the application-defined function to be
4560 ** a BLOB containing all zero bytes and N bytes in size.
4562 ** ^The sqlite3_result_double() interface sets the result from
4563 ** an application-defined function to be a floating point value specified
4564 ** by its 2nd argument.
4566 ** ^The sqlite3_result_error() and sqlite3_result_error16() functions
4567 ** cause the implemented SQL function to throw an exception.
4568 ** ^SQLite uses the string pointed to by the
4569 ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
4570 ** as the text of an error message. ^SQLite interprets the error
4571 ** message string from sqlite3_result_error() as UTF-8. ^SQLite
4572 ** interprets the string from sqlite3_result_error16() as UTF-16 in native
4573 ** byte order. ^If the third parameter to sqlite3_result_error()
4574 ** or sqlite3_result_error16() is negative then SQLite takes as the error
4575 ** message all text up through the first zero character.
4576 ** ^If the third parameter to sqlite3_result_error() or
4577 ** sqlite3_result_error16() is non-negative then SQLite takes that many
4578 ** bytes (not characters) from the 2nd parameter as the error message.
4579 ** ^The sqlite3_result_error() and sqlite3_result_error16()
4580 ** routines make a private copy of the error message text before
4581 ** they return. Hence, the calling function can deallocate or
4582 ** modify the text after they return without harm.
4583 ** ^The sqlite3_result_error_code() function changes the error code
4584 ** returned by SQLite as a result of an error in a function. ^By default,
4585 ** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error()
4586 ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
4588 ** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an
4589 ** error indicating that a string or BLOB is too long to represent.
4591 ** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an
4592 ** error indicating that a memory allocation failed.
4594 ** ^The sqlite3_result_int() interface sets the return value
4595 ** of the application-defined function to be the 32-bit signed integer
4596 ** value given in the 2nd argument.
4597 ** ^The sqlite3_result_int64() interface sets the return value
4598 ** of the application-defined function to be the 64-bit signed integer
4599 ** value given in the 2nd argument.
4601 ** ^The sqlite3_result_null() interface sets the return value
4602 ** of the application-defined function to be NULL.
4604 ** ^The sqlite3_result_text(), sqlite3_result_text16(),
4605 ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
4606 ** set the return value of the application-defined function to be
4607 ** a text string which is represented as UTF-8, UTF-16 native byte order,
4608 ** UTF-16 little endian, or UTF-16 big endian, respectively.
4609 ** ^The sqlite3_result_text64() interface sets the return value of an
4610 ** application-defined function to be a text string in an encoding
4611 ** specified by the fifth (and last) parameter, which must be one
4612 ** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE].
4613 ** ^SQLite takes the text result from the application from
4614 ** the 2nd parameter of the sqlite3_result_text* interfaces.
4615 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
4616 ** is negative, then SQLite takes result text from the 2nd parameter
4617 ** through the first zero character.
4618 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
4619 ** is non-negative, then as many bytes (not characters) of the text
4620 ** pointed to by the 2nd parameter are taken as the application-defined
4621 ** function result. If the 3rd parameter is non-negative, then it
4622 ** must be the byte offset into the string where the NUL terminator would
4623 ** appear if the string where NUL terminated. If any NUL characters occur
4624 ** in the string at a byte offset that is less than the value of the 3rd
4625 ** parameter, then the resulting string will contain embedded NULs and the
4626 ** result of expressions operating on strings with embedded NULs is undefined.
4627 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
4628 ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
4629 ** function as the destructor on the text or BLOB result when it has
4630 ** finished using that result.
4631 ** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
4632 ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
4633 ** assumes that the text or BLOB result is in constant space and does not
4634 ** copy the content of the parameter nor call a destructor on the content
4635 ** when it has finished using that result.
4636 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
4637 ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
4638 ** then SQLite makes a copy of the result into space obtained from
4639 ** from [sqlite3_malloc()] before it returns.
4641 ** ^The sqlite3_result_value() interface sets the result of
4642 ** the application-defined function to be a copy of the
4643 ** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The
4644 ** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
4645 ** so that the [sqlite3_value] specified in the parameter may change or
4646 ** be deallocated after sqlite3_result_value() returns without harm.
4647 ** ^A [protected sqlite3_value] object may always be used where an
4648 ** [unprotected sqlite3_value] object is required, so either
4649 ** kind of [sqlite3_value] object can be used with this interface.
4651 ** If these routines are called from within the different thread
4652 ** than the one containing the application-defined function that received
4653 ** the [sqlite3_context] pointer, the results are undefined.
4655 SQLITE_API void SQLITE_STDCALL sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
4656 SQLITE_API void SQLITE_STDCALL sqlite3_result_blob64(sqlite3_context*,const void*,
4657 sqlite3_uint64,void(*)(void*));
4658 SQLITE_API void SQLITE_STDCALL sqlite3_result_double(sqlite3_context*, double);
4659 SQLITE_API void SQLITE_STDCALL sqlite3_result_error(sqlite3_context*, const char*, int);
4660 SQLITE_API void SQLITE_STDCALL sqlite3_result_error16(sqlite3_context*, const void*, int);
4661 SQLITE_API void SQLITE_STDCALL sqlite3_result_error_toobig(sqlite3_context*);
4662 SQLITE_API void SQLITE_STDCALL sqlite3_result_error_nomem(sqlite3_context*);
4663 SQLITE_API void SQLITE_STDCALL sqlite3_result_error_code(sqlite3_context*, int);
4664 SQLITE_API void SQLITE_STDCALL sqlite3_result_int(sqlite3_context*, int);
4665 SQLITE_API void SQLITE_STDCALL sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
4666 SQLITE_API void SQLITE_STDCALL sqlite3_result_null(sqlite3_context*);
4667 SQLITE_API void SQLITE_STDCALL sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
4668 SQLITE_API void SQLITE_STDCALL sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64,
4669 void(*)(void*), unsigned char encoding);
4670 SQLITE_API void SQLITE_STDCALL sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
4671 SQLITE_API void SQLITE_STDCALL sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
4672 SQLITE_API void SQLITE_STDCALL sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
4673 SQLITE_API void SQLITE_STDCALL sqlite3_result_value(sqlite3_context*, sqlite3_value*);
4674 SQLITE_API void SQLITE_STDCALL sqlite3_result_zeroblob(sqlite3_context*, int n);
4675 SQLITE_API int SQLITE_STDCALL sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n);
4679 ** CAPI3REF: Setting The Subtype Of An SQL Function
4680 ** METHOD: sqlite3_context
4682 ** The sqlite3_result_subtype(C,T) function causes the subtype of
4683 ** the result from the [application-defined SQL function] with
4684 ** [sqlite3_context] C to be the value T. Only the lower 8 bits
4685 ** of the subtype T are preserved in current versions of SQLite;
4686 ** higher order bits are discarded.
4687 ** The number of subtype bytes preserved by SQLite might increase
4688 ** in future releases of SQLite.
4690 SQLITE_API void SQLITE_STDCALL sqlite3_result_subtype(sqlite3_context*,unsigned int);
4693 ** CAPI3REF: Define New Collating Sequences
4696 ** ^These functions add, remove, or modify a [collation] associated
4697 ** with the [database connection] specified as the first argument.
4699 ** ^The name of the collation is a UTF-8 string
4700 ** for sqlite3_create_collation() and sqlite3_create_collation_v2()
4701 ** and a UTF-16 string in native byte order for sqlite3_create_collation16().
4702 ** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
4703 ** considered to be the same name.
4705 ** ^(The third argument (eTextRep) must be one of the constants:
4707 ** <li> [SQLITE_UTF8],
4708 ** <li> [SQLITE_UTF16LE],
4709 ** <li> [SQLITE_UTF16BE],
4710 ** <li> [SQLITE_UTF16], or
4711 ** <li> [SQLITE_UTF16_ALIGNED].
4713 ** ^The eTextRep argument determines the encoding of strings passed
4714 ** to the collating function callback, xCallback.
4715 ** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
4716 ** force strings to be UTF16 with native byte order.
4717 ** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
4718 ** on an even byte address.
4720 ** ^The fourth argument, pArg, is an application data pointer that is passed
4721 ** through as the first argument to the collating function callback.
4723 ** ^The fifth argument, xCallback, is a pointer to the collating function.
4724 ** ^Multiple collating functions can be registered using the same name but
4725 ** with different eTextRep parameters and SQLite will use whichever
4726 ** function requires the least amount of data transformation.
4727 ** ^If the xCallback argument is NULL then the collating function is
4728 ** deleted. ^When all collating functions having the same name are deleted,
4729 ** that collation is no longer usable.
4731 ** ^The collating function callback is invoked with a copy of the pArg
4732 ** application data pointer and with two strings in the encoding specified
4733 ** by the eTextRep argument. The collating function must return an
4734 ** integer that is negative, zero, or positive
4735 ** if the first string is less than, equal to, or greater than the second,
4736 ** respectively. A collating function must always return the same answer
4737 ** given the same inputs. If two or more collating functions are registered
4738 ** to the same collation name (using different eTextRep values) then all
4739 ** must give an equivalent answer when invoked with equivalent strings.
4740 ** The collating function must obey the following properties for all
4741 ** strings A, B, and C:
4744 ** <li> If A==B then B==A.
4745 ** <li> If A==B and B==C then A==C.
4746 ** <li> If A<B THEN B>A.
4747 ** <li> If A<B and B<C then A<C.
4750 ** If a collating function fails any of the above constraints and that
4751 ** collating function is registered and used, then the behavior of SQLite
4754 ** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
4755 ** with the addition that the xDestroy callback is invoked on pArg when
4756 ** the collating function is deleted.
4757 ** ^Collating functions are deleted when they are overridden by later
4758 ** calls to the collation creation functions or when the
4759 ** [database connection] is closed using [sqlite3_close()].
4761 ** ^The xDestroy callback is <u>not</u> called if the
4762 ** sqlite3_create_collation_v2() function fails. Applications that invoke
4763 ** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
4764 ** check the return code and dispose of the application data pointer
4765 ** themselves rather than expecting SQLite to deal with it for them.
4766 ** This is different from every other SQLite interface. The inconsistency
4767 ** is unfortunate but cannot be changed without breaking backwards
4770 ** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
4772 SQLITE_API int SQLITE_STDCALL sqlite3_create_collation(
4777 int(*xCompare)(void*,int,const void*,int,const void*)
4779 SQLITE_API int SQLITE_STDCALL sqlite3_create_collation_v2(
4784 int(*xCompare)(void*,int,const void*,int,const void*),
4785 void(*xDestroy)(void*)
4787 SQLITE_API int SQLITE_STDCALL sqlite3_create_collation16(
4792 int(*xCompare)(void*,int,const void*,int,const void*)
4796 ** CAPI3REF: Collation Needed Callbacks
4799 ** ^To avoid having to register all collation sequences before a database
4800 ** can be used, a single callback function may be registered with the
4801 ** [database connection] to be invoked whenever an undefined collation
4802 ** sequence is required.
4804 ** ^If the function is registered using the sqlite3_collation_needed() API,
4805 ** then it is passed the names of undefined collation sequences as strings
4806 ** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
4807 ** the names are passed as UTF-16 in machine native byte order.
4808 ** ^A call to either function replaces the existing collation-needed callback.
4810 ** ^(When the callback is invoked, the first argument passed is a copy
4811 ** of the second argument to sqlite3_collation_needed() or
4812 ** sqlite3_collation_needed16(). The second argument is the database
4813 ** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
4814 ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
4815 ** sequence function required. The fourth parameter is the name of the
4816 ** required collation sequence.)^
4818 ** The callback function should register the desired collation using
4819 ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
4820 ** [sqlite3_create_collation_v2()].
4822 SQLITE_API int SQLITE_STDCALL sqlite3_collation_needed(
4825 void(*)(void*,sqlite3*,int eTextRep,const char*)
4827 SQLITE_API int SQLITE_STDCALL sqlite3_collation_needed16(
4830 void(*)(void*,sqlite3*,int eTextRep,const void*)
4833 #ifdef SQLITE_HAS_CODEC
4835 ** Specify the key for an encrypted database. This routine should be
4836 ** called right after sqlite3_open().
4838 ** The code to implement this API is not available in the public release
4841 SQLITE_API int SQLITE_STDCALL sqlite3_key(
4842 sqlite3 *db, /* Database to be rekeyed */
4843 const void *pKey, int nKey /* The key */
4845 SQLITE_API int SQLITE_STDCALL sqlite3_key_v2(
4846 sqlite3 *db, /* Database to be rekeyed */
4847 const char *zDbName, /* Name of the database */
4848 const void *pKey, int nKey /* The key */
4852 ** Change the key on an open database. If the current database is not
4853 ** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the
4854 ** database is decrypted.
4856 ** The code to implement this API is not available in the public release
4859 SQLITE_API int SQLITE_STDCALL sqlite3_rekey(
4860 sqlite3 *db, /* Database to be rekeyed */
4861 const void *pKey, int nKey /* The new key */
4863 SQLITE_API int SQLITE_STDCALL sqlite3_rekey_v2(
4864 sqlite3 *db, /* Database to be rekeyed */
4865 const char *zDbName, /* Name of the database */
4866 const void *pKey, int nKey /* The new key */
4870 ** Specify the activation key for a SEE database. Unless
4871 ** activated, none of the SEE routines will work.
4873 SQLITE_API void SQLITE_STDCALL sqlite3_activate_see(
4874 const char *zPassPhrase /* Activation phrase */
4878 #ifdef SQLITE_ENABLE_CEROD
4880 ** Specify the activation key for a CEROD database. Unless
4881 ** activated, none of the CEROD routines will work.
4883 SQLITE_API void SQLITE_STDCALL sqlite3_activate_cerod(
4884 const char *zPassPhrase /* Activation phrase */
4889 ** CAPI3REF: Suspend Execution For A Short Time
4891 ** The sqlite3_sleep() function causes the current thread to suspend execution
4892 ** for at least a number of milliseconds specified in its parameter.
4894 ** If the operating system does not support sleep requests with
4895 ** millisecond time resolution, then the time will be rounded up to
4896 ** the nearest second. The number of milliseconds of sleep actually
4897 ** requested from the operating system is returned.
4899 ** ^SQLite implements this interface by calling the xSleep()
4900 ** method of the default [sqlite3_vfs] object. If the xSleep() method
4901 ** of the default VFS is not implemented correctly, or not implemented at
4902 ** all, then the behavior of sqlite3_sleep() may deviate from the description
4903 ** in the previous paragraphs.
4905 SQLITE_API int SQLITE_STDCALL sqlite3_sleep(int);
4908 ** CAPI3REF: Name Of The Folder Holding Temporary Files
4910 ** ^(If this global variable is made to point to a string which is
4911 ** the name of a folder (a.k.a. directory), then all temporary files
4912 ** created by SQLite when using a built-in [sqlite3_vfs | VFS]
4913 ** will be placed in that directory.)^ ^If this variable
4914 ** is a NULL pointer, then SQLite performs a search for an appropriate
4915 ** temporary file directory.
4917 ** Applications are strongly discouraged from using this global variable.
4918 ** It is required to set a temporary folder on Windows Runtime (WinRT).
4919 ** But for all other platforms, it is highly recommended that applications
4920 ** neither read nor write this variable. This global variable is a relic
4921 ** that exists for backwards compatibility of legacy applications and should
4922 ** be avoided in new projects.
4924 ** It is not safe to read or modify this variable in more than one
4925 ** thread at a time. It is not safe to read or modify this variable
4926 ** if a [database connection] is being used at the same time in a separate
4928 ** It is intended that this variable be set once
4929 ** as part of process initialization and before any SQLite interface
4930 ** routines have been called and that this variable remain unchanged
4933 ** ^The [temp_store_directory pragma] may modify this variable and cause
4934 ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,
4935 ** the [temp_store_directory pragma] always assumes that any string
4936 ** that this variable points to is held in memory obtained from
4937 ** [sqlite3_malloc] and the pragma may attempt to free that memory
4938 ** using [sqlite3_free].
4939 ** Hence, if this variable is modified directly, either it should be
4940 ** made NULL or made to point to memory obtained from [sqlite3_malloc]
4941 ** or else the use of the [temp_store_directory pragma] should be avoided.
4942 ** Except when requested by the [temp_store_directory pragma], SQLite
4943 ** does not free the memory that sqlite3_temp_directory points to. If
4944 ** the application wants that memory to be freed, it must do
4945 ** so itself, taking care to only do so after all [database connection]
4946 ** objects have been destroyed.
4948 ** <b>Note to Windows Runtime users:</b> The temporary directory must be set
4949 ** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various
4950 ** features that require the use of temporary files may fail. Here is an
4951 ** example of how to do this using C++ with the Windows Runtime:
4953 ** <blockquote><pre>
4954 ** LPCWSTR zPath = Windows::Storage::ApplicationData::Current->
4955 ** TemporaryFolder->Path->Data();
4956 ** char zPathBuf[MAX_PATH + 1];
4957 ** memset(zPathBuf, 0, sizeof(zPathBuf));
4958 ** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),
4959 ** NULL, NULL);
4960 ** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);
4961 ** </pre></blockquote>
4963 SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory;
4966 ** CAPI3REF: Name Of The Folder Holding Database Files
4968 ** ^(If this global variable is made to point to a string which is
4969 ** the name of a folder (a.k.a. directory), then all database files
4970 ** specified with a relative pathname and created or accessed by
4971 ** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed
4972 ** to be relative to that directory.)^ ^If this variable is a NULL
4973 ** pointer, then SQLite assumes that all database files specified
4974 ** with a relative pathname are relative to the current directory
4975 ** for the process. Only the windows VFS makes use of this global
4976 ** variable; it is ignored by the unix VFS.
4978 ** Changing the value of this variable while a database connection is
4979 ** open can result in a corrupt database.
4981 ** It is not safe to read or modify this variable in more than one
4982 ** thread at a time. It is not safe to read or modify this variable
4983 ** if a [database connection] is being used at the same time in a separate
4985 ** It is intended that this variable be set once
4986 ** as part of process initialization and before any SQLite interface
4987 ** routines have been called and that this variable remain unchanged
4990 ** ^The [data_store_directory pragma] may modify this variable and cause
4991 ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,
4992 ** the [data_store_directory pragma] always assumes that any string
4993 ** that this variable points to is held in memory obtained from
4994 ** [sqlite3_malloc] and the pragma may attempt to free that memory
4995 ** using [sqlite3_free].
4996 ** Hence, if this variable is modified directly, either it should be
4997 ** made NULL or made to point to memory obtained from [sqlite3_malloc]
4998 ** or else the use of the [data_store_directory pragma] should be avoided.
5000 SQLITE_API SQLITE_EXTERN char *sqlite3_data_directory;
5003 ** CAPI3REF: Test For Auto-Commit Mode
5004 ** KEYWORDS: {autocommit mode}
5007 ** ^The sqlite3_get_autocommit() interface returns non-zero or
5008 ** zero if the given database connection is or is not in autocommit mode,
5009 ** respectively. ^Autocommit mode is on by default.
5010 ** ^Autocommit mode is disabled by a [BEGIN] statement.
5011 ** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
5013 ** If certain kinds of errors occur on a statement within a multi-statement
5014 ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
5015 ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
5016 ** transaction might be rolled back automatically. The only way to
5017 ** find out whether SQLite automatically rolled back the transaction after
5018 ** an error is to use this function.
5020 ** If another thread changes the autocommit status of the database
5021 ** connection while this routine is running, then the return value
5024 SQLITE_API int SQLITE_STDCALL sqlite3_get_autocommit(sqlite3*);
5027 ** CAPI3REF: Find The Database Handle Of A Prepared Statement
5028 ** METHOD: sqlite3_stmt
5030 ** ^The sqlite3_db_handle interface returns the [database connection] handle
5031 ** to which a [prepared statement] belongs. ^The [database connection]
5032 ** returned by sqlite3_db_handle is the same [database connection]
5033 ** that was the first argument
5034 ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
5035 ** create the statement in the first place.
5037 SQLITE_API sqlite3 *SQLITE_STDCALL sqlite3_db_handle(sqlite3_stmt*);
5040 ** CAPI3REF: Return The Filename For A Database Connection
5043 ** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename
5044 ** associated with database N of connection D. ^The main database file
5045 ** has the name "main". If there is no attached database N on the database
5046 ** connection D, or if database N is a temporary or in-memory database, then
5047 ** a NULL pointer is returned.
5049 ** ^The filename returned by this function is the output of the
5050 ** xFullPathname method of the [VFS]. ^In other words, the filename
5051 ** will be an absolute pathname, even if the filename used
5052 ** to open the database originally was a URI or relative pathname.
5054 SQLITE_API const char *SQLITE_STDCALL sqlite3_db_filename(sqlite3 *db, const char *zDbName);
5057 ** CAPI3REF: Determine if a database is read-only
5060 ** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N
5061 ** of connection D is read-only, 0 if it is read/write, or -1 if N is not
5062 ** the name of a database on connection D.
5064 SQLITE_API int SQLITE_STDCALL sqlite3_db_readonly(sqlite3 *db, const char *zDbName);
5067 ** CAPI3REF: Find the next prepared statement
5070 ** ^This interface returns a pointer to the next [prepared statement] after
5071 ** pStmt associated with the [database connection] pDb. ^If pStmt is NULL
5072 ** then this interface returns a pointer to the first prepared statement
5073 ** associated with the database connection pDb. ^If no prepared statement
5074 ** satisfies the conditions of this routine, it returns NULL.
5076 ** The [database connection] pointer D in a call to
5077 ** [sqlite3_next_stmt(D,S)] must refer to an open database
5078 ** connection and in particular must not be a NULL pointer.
5080 SQLITE_API sqlite3_stmt *SQLITE_STDCALL sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
5083 ** CAPI3REF: Commit And Rollback Notification Callbacks
5086 ** ^The sqlite3_commit_hook() interface registers a callback
5087 ** function to be invoked whenever a transaction is [COMMIT | committed].
5088 ** ^Any callback set by a previous call to sqlite3_commit_hook()
5089 ** for the same database connection is overridden.
5090 ** ^The sqlite3_rollback_hook() interface registers a callback
5091 ** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
5092 ** ^Any callback set by a previous call to sqlite3_rollback_hook()
5093 ** for the same database connection is overridden.
5094 ** ^The pArg argument is passed through to the callback.
5095 ** ^If the callback on a commit hook function returns non-zero,
5096 ** then the commit is converted into a rollback.
5098 ** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
5099 ** return the P argument from the previous call of the same function
5100 ** on the same [database connection] D, or NULL for
5101 ** the first call for each function on D.
5103 ** The commit and rollback hook callbacks are not reentrant.
5104 ** The callback implementation must not do anything that will modify
5105 ** the database connection that invoked the callback. Any actions
5106 ** to modify the database connection must be deferred until after the
5107 ** completion of the [sqlite3_step()] call that triggered the commit
5108 ** or rollback hook in the first place.
5109 ** Note that running any other SQL statements, including SELECT statements,
5110 ** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
5111 ** the database connections for the meaning of "modify" in this paragraph.
5113 ** ^Registering a NULL function disables the callback.
5115 ** ^When the commit hook callback routine returns zero, the [COMMIT]
5116 ** operation is allowed to continue normally. ^If the commit hook
5117 ** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
5118 ** ^The rollback hook is invoked on a rollback that results from a commit
5119 ** hook returning non-zero, just as it would be with any other rollback.
5121 ** ^For the purposes of this API, a transaction is said to have been
5122 ** rolled back if an explicit "ROLLBACK" statement is executed, or
5123 ** an error or constraint causes an implicit rollback to occur.
5124 ** ^The rollback callback is not invoked if a transaction is
5125 ** automatically rolled back because the database connection is closed.
5127 ** See also the [sqlite3_update_hook()] interface.
5129 SQLITE_API void *SQLITE_STDCALL sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
5130 SQLITE_API void *SQLITE_STDCALL sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
5133 ** CAPI3REF: Data Change Notification Callbacks
5136 ** ^The sqlite3_update_hook() interface registers a callback function
5137 ** with the [database connection] identified by the first argument
5138 ** to be invoked whenever a row is updated, inserted or deleted in
5140 ** ^Any callback set by a previous call to this function
5141 ** for the same database connection is overridden.
5143 ** ^The second argument is a pointer to the function to invoke when a
5144 ** row is updated, inserted or deleted in a rowid table.
5145 ** ^The first argument to the callback is a copy of the third argument
5146 ** to sqlite3_update_hook().
5147 ** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
5148 ** or [SQLITE_UPDATE], depending on the operation that caused the callback
5150 ** ^The third and fourth arguments to the callback contain pointers to the
5151 ** database and table name containing the affected row.
5152 ** ^The final callback parameter is the [rowid] of the row.
5153 ** ^In the case of an update, this is the [rowid] after the update takes place.
5155 ** ^(The update hook is not invoked when internal system tables are
5156 ** modified (i.e. sqlite_master and sqlite_sequence).)^
5157 ** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified.
5159 ** ^In the current implementation, the update hook
5160 ** is not invoked when duplication rows are deleted because of an
5161 ** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook
5162 ** invoked when rows are deleted using the [truncate optimization].
5163 ** The exceptions defined in this paragraph might change in a future
5164 ** release of SQLite.
5166 ** The update hook implementation must not do anything that will modify
5167 ** the database connection that invoked the update hook. Any actions
5168 ** to modify the database connection must be deferred until after the
5169 ** completion of the [sqlite3_step()] call that triggered the update hook.
5170 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
5171 ** database connections for the meaning of "modify" in this paragraph.
5173 ** ^The sqlite3_update_hook(D,C,P) function
5174 ** returns the P argument from the previous call
5175 ** on the same [database connection] D, or NULL for
5176 ** the first call on D.
5178 ** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()]
5181 SQLITE_API void *SQLITE_STDCALL sqlite3_update_hook(
5183 void(*)(void *,int ,char const *,char const *,sqlite3_int64),
5188 ** CAPI3REF: Enable Or Disable Shared Pager Cache
5190 ** ^(This routine enables or disables the sharing of the database cache
5191 ** and schema data structures between [database connection | connections]
5192 ** to the same database. Sharing is enabled if the argument is true
5193 ** and disabled if the argument is false.)^
5195 ** ^Cache sharing is enabled and disabled for an entire process.
5196 ** This is a change as of SQLite version 3.5.0. In prior versions of SQLite,
5197 ** sharing was enabled or disabled for each thread separately.
5199 ** ^(The cache sharing mode set by this interface effects all subsequent
5200 ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
5201 ** Existing database connections continue use the sharing mode
5202 ** that was in effect at the time they were opened.)^
5204 ** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
5205 ** successfully. An [error code] is returned otherwise.)^
5207 ** ^Shared cache is disabled by default. But this might change in
5208 ** future releases of SQLite. Applications that care about shared
5209 ** cache setting should set it explicitly.
5211 ** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0
5212 ** and will always return SQLITE_MISUSE. On those systems,
5213 ** shared cache mode should be enabled per-database connection via
5214 ** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE].
5216 ** This interface is threadsafe on processors where writing a
5217 ** 32-bit integer is atomic.
5219 ** See Also: [SQLite Shared-Cache Mode]
5221 SQLITE_API int SQLITE_STDCALL sqlite3_enable_shared_cache(int);
5224 ** CAPI3REF: Attempt To Free Heap Memory
5226 ** ^The sqlite3_release_memory() interface attempts to free N bytes
5227 ** of heap memory by deallocating non-essential memory allocations
5228 ** held by the database library. Memory used to cache database
5229 ** pages to improve performance is an example of non-essential memory.
5230 ** ^sqlite3_release_memory() returns the number of bytes actually freed,
5231 ** which might be more or less than the amount requested.
5232 ** ^The sqlite3_release_memory() routine is a no-op returning zero
5233 ** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
5235 ** See also: [sqlite3_db_release_memory()]
5237 SQLITE_API int SQLITE_STDCALL sqlite3_release_memory(int);
5240 ** CAPI3REF: Free Memory Used By A Database Connection
5243 ** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap
5244 ** memory as possible from database connection D. Unlike the
5245 ** [sqlite3_release_memory()] interface, this interface is in effect even
5246 ** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
5249 ** See also: [sqlite3_release_memory()]
5251 SQLITE_API int SQLITE_STDCALL sqlite3_db_release_memory(sqlite3*);
5254 ** CAPI3REF: Impose A Limit On Heap Size
5256 ** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
5257 ** soft limit on the amount of heap memory that may be allocated by SQLite.
5258 ** ^SQLite strives to keep heap memory utilization below the soft heap
5259 ** limit by reducing the number of pages held in the page cache
5260 ** as heap memory usages approaches the limit.
5261 ** ^The soft heap limit is "soft" because even though SQLite strives to stay
5262 ** below the limit, it will exceed the limit rather than generate
5263 ** an [SQLITE_NOMEM] error. In other words, the soft heap limit
5264 ** is advisory only.
5266 ** ^The return value from sqlite3_soft_heap_limit64() is the size of
5267 ** the soft heap limit prior to the call, or negative in the case of an
5268 ** error. ^If the argument N is negative
5269 ** then no change is made to the soft heap limit. Hence, the current
5270 ** size of the soft heap limit can be determined by invoking
5271 ** sqlite3_soft_heap_limit64() with a negative argument.
5273 ** ^If the argument N is zero then the soft heap limit is disabled.
5275 ** ^(The soft heap limit is not enforced in the current implementation
5276 ** if one or more of following conditions are true:
5279 ** <li> The soft heap limit is set to zero.
5280 ** <li> Memory accounting is disabled using a combination of the
5281 ** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
5282 ** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
5283 ** <li> An alternative page cache implementation is specified using
5284 ** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
5285 ** <li> The page cache allocates from its own memory pool supplied
5286 ** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
5290 ** Beginning with SQLite version 3.7.3, the soft heap limit is enforced
5291 ** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT]
5292 ** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT],
5293 ** the soft heap limit is enforced on every memory allocation. Without
5294 ** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced
5295 ** when memory is allocated by the page cache. Testing suggests that because
5296 ** the page cache is the predominate memory user in SQLite, most
5297 ** applications will achieve adequate soft heap limit enforcement without
5298 ** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT].
5300 ** The circumstances under which SQLite will enforce the soft heap limit may
5301 ** changes in future releases of SQLite.
5303 SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_soft_heap_limit64(sqlite3_int64 N);
5306 ** CAPI3REF: Deprecated Soft Heap Limit Interface
5309 ** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
5310 ** interface. This routine is provided for historical compatibility
5311 ** only. All new applications should use the
5312 ** [sqlite3_soft_heap_limit64()] interface rather than this one.
5314 SQLITE_API SQLITE_DEPRECATED void SQLITE_STDCALL sqlite3_soft_heap_limit(int N);
5318 ** CAPI3REF: Extract Metadata About A Column Of A Table
5321 ** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns
5322 ** information about column C of table T in database D
5323 ** on [database connection] X.)^ ^The sqlite3_table_column_metadata()
5324 ** interface returns SQLITE_OK and fills in the non-NULL pointers in
5325 ** the final five arguments with appropriate values if the specified
5326 ** column exists. ^The sqlite3_table_column_metadata() interface returns
5327 ** SQLITE_ERROR and if the specified column does not exist.
5328 ** ^If the column-name parameter to sqlite3_table_column_metadata() is a
5329 ** NULL pointer, then this routine simply checks for the existance of the
5330 ** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it
5333 ** ^The column is identified by the second, third and fourth parameters to
5334 ** this function. ^(The second parameter is either the name of the database
5335 ** (i.e. "main", "temp", or an attached database) containing the specified
5336 ** table or NULL.)^ ^If it is NULL, then all attached databases are searched
5337 ** for the table using the same algorithm used by the database engine to
5338 ** resolve unqualified table references.
5340 ** ^The third and fourth parameters to this function are the table and column
5341 ** name of the desired column, respectively.
5343 ** ^Metadata is returned by writing to the memory locations passed as the 5th
5344 ** and subsequent parameters to this function. ^Any of these arguments may be
5345 ** NULL, in which case the corresponding element of metadata is omitted.
5348 ** <table border="1">
5349 ** <tr><th> Parameter <th> Output<br>Type <th> Description
5351 ** <tr><td> 5th <td> const char* <td> Data type
5352 ** <tr><td> 6th <td> const char* <td> Name of default collation sequence
5353 ** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint
5354 ** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY
5355 ** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT]
5359 ** ^The memory pointed to by the character pointers returned for the
5360 ** declaration type and collation sequence is valid until the next
5361 ** call to any SQLite API function.
5363 ** ^If the specified table is actually a view, an [error code] is returned.
5365 ** ^If the specified column is "rowid", "oid" or "_rowid_" and the table
5366 ** is not a [WITHOUT ROWID] table and an
5367 ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
5368 ** parameters are set for the explicitly declared column. ^(If there is no
5369 ** [INTEGER PRIMARY KEY] column, then the outputs
5370 ** for the [rowid] are set as follows:
5373 ** data type: "INTEGER"
5374 ** collation sequence: "BINARY"
5377 ** auto increment: 0
5380 ** ^This function causes all database schemas to be read from disk and
5381 ** parsed, if that has not already been done, and returns an error if
5382 ** any errors are encountered while loading the schema.
5384 SQLITE_API int SQLITE_STDCALL sqlite3_table_column_metadata(
5385 sqlite3 *db, /* Connection handle */
5386 const char *zDbName, /* Database name or NULL */
5387 const char *zTableName, /* Table name */
5388 const char *zColumnName, /* Column name */
5389 char const **pzDataType, /* OUTPUT: Declared data type */
5390 char const **pzCollSeq, /* OUTPUT: Collation sequence name */
5391 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */
5392 int *pPrimaryKey, /* OUTPUT: True if column part of PK */
5393 int *pAutoinc /* OUTPUT: True if column is auto-increment */
5397 ** CAPI3REF: Load An Extension
5400 ** ^This interface loads an SQLite extension library from the named file.
5402 ** ^The sqlite3_load_extension() interface attempts to load an
5403 ** [SQLite extension] library contained in the file zFile. If
5404 ** the file cannot be loaded directly, attempts are made to load
5405 ** with various operating-system specific extensions added.
5406 ** So for example, if "samplelib" cannot be loaded, then names like
5407 ** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might
5410 ** ^The entry point is zProc.
5411 ** ^(zProc may be 0, in which case SQLite will try to come up with an
5412 ** entry point name on its own. It first tries "sqlite3_extension_init".
5413 ** If that does not work, it constructs a name "sqlite3_X_init" where the
5414 ** X is consists of the lower-case equivalent of all ASCII alphabetic
5415 ** characters in the filename from the last "/" to the first following
5416 ** "." and omitting any initial "lib".)^
5417 ** ^The sqlite3_load_extension() interface returns
5418 ** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
5419 ** ^If an error occurs and pzErrMsg is not 0, then the
5420 ** [sqlite3_load_extension()] interface shall attempt to
5421 ** fill *pzErrMsg with error message text stored in memory
5422 ** obtained from [sqlite3_malloc()]. The calling function
5423 ** should free this memory by calling [sqlite3_free()].
5425 ** ^Extension loading must be enabled using
5426 ** [sqlite3_enable_load_extension()] prior to calling this API,
5427 ** otherwise an error will be returned.
5429 ** See also the [load_extension() SQL function].
5431 SQLITE_API int SQLITE_STDCALL sqlite3_load_extension(
5432 sqlite3 *db, /* Load the extension into this database connection */
5433 const char *zFile, /* Name of the shared library containing extension */
5434 const char *zProc, /* Entry point. Derived from zFile if 0 */
5435 char **pzErrMsg /* Put error message here if not 0 */
5439 ** CAPI3REF: Enable Or Disable Extension Loading
5442 ** ^So as not to open security holes in older applications that are
5443 ** unprepared to deal with [extension loading], and as a means of disabling
5444 ** [extension loading] while evaluating user-entered SQL, the following API
5445 ** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
5447 ** ^Extension loading is off by default.
5448 ** ^Call the sqlite3_enable_load_extension() routine with onoff==1
5449 ** to turn extension loading on and call it with onoff==0 to turn
5450 ** it back off again.
5452 SQLITE_API int SQLITE_STDCALL sqlite3_enable_load_extension(sqlite3 *db, int onoff);
5455 ** CAPI3REF: Automatically Load Statically Linked Extensions
5457 ** ^This interface causes the xEntryPoint() function to be invoked for
5458 ** each new [database connection] that is created. The idea here is that
5459 ** xEntryPoint() is the entry point for a statically linked [SQLite extension]
5460 ** that is to be automatically loaded into all new database connections.
5462 ** ^(Even though the function prototype shows that xEntryPoint() takes
5463 ** no arguments and returns void, SQLite invokes xEntryPoint() with three
5464 ** arguments and expects and integer result as if the signature of the
5465 ** entry point where as follows:
5467 ** <blockquote><pre>
5468 ** int xEntryPoint(
5469 ** sqlite3 *db,
5470 ** const char **pzErrMsg,
5471 ** const struct sqlite3_api_routines *pThunk
5473 ** </pre></blockquote>)^
5475 ** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
5476 ** point to an appropriate error message (obtained from [sqlite3_mprintf()])
5477 ** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg
5478 ** is NULL before calling the xEntryPoint(). ^SQLite will invoke
5479 ** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any
5480 ** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
5481 ** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
5483 ** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
5484 ** on the list of automatic extensions is a harmless no-op. ^No entry point
5485 ** will be called more than once for each database connection that is opened.
5487 ** See also: [sqlite3_reset_auto_extension()]
5488 ** and [sqlite3_cancel_auto_extension()]
5490 SQLITE_API int SQLITE_STDCALL sqlite3_auto_extension(void (*xEntryPoint)(void));
5493 ** CAPI3REF: Cancel Automatic Extension Loading
5495 ** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the
5496 ** initialization routine X that was registered using a prior call to
5497 ** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)]
5498 ** routine returns 1 if initialization routine X was successfully
5499 ** unregistered and it returns 0 if X was not on the list of initialization
5502 SQLITE_API int SQLITE_STDCALL sqlite3_cancel_auto_extension(void (*xEntryPoint)(void));
5505 ** CAPI3REF: Reset Automatic Extension Loading
5507 ** ^This interface disables all automatic extensions previously
5508 ** registered using [sqlite3_auto_extension()].
5510 SQLITE_API void SQLITE_STDCALL sqlite3_reset_auto_extension(void);
5513 ** The interface to the virtual-table mechanism is currently considered
5514 ** to be experimental. The interface might change in incompatible ways.
5515 ** If this is a problem for you, do not use the interface at this time.
5517 ** When the virtual-table mechanism stabilizes, we will declare the
5518 ** interface fixed, support it indefinitely, and remove this comment.
5522 ** Structures used by the virtual table interface
5524 typedef struct sqlite3_vtab sqlite3_vtab;
5525 typedef struct sqlite3_index_info sqlite3_index_info;
5526 typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
5527 typedef struct sqlite3_module sqlite3_module;
5530 ** CAPI3REF: Virtual Table Object
5531 ** KEYWORDS: sqlite3_module {virtual table module}
5533 ** This structure, sometimes called a "virtual table module",
5534 ** defines the implementation of a [virtual tables].
5535 ** This structure consists mostly of methods for the module.
5537 ** ^A virtual table module is created by filling in a persistent
5538 ** instance of this structure and passing a pointer to that instance
5539 ** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
5540 ** ^The registration remains valid until it is replaced by a different
5541 ** module or until the [database connection] closes. The content
5542 ** of this structure must not change while it is registered with
5543 ** any database connection.
5545 struct sqlite3_module {
5547 int (*xCreate)(sqlite3*, void *pAux,
5548 int argc, const char *const*argv,
5549 sqlite3_vtab **ppVTab, char**);
5550 int (*xConnect)(sqlite3*, void *pAux,
5551 int argc, const char *const*argv,
5552 sqlite3_vtab **ppVTab, char**);
5553 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
5554 int (*xDisconnect)(sqlite3_vtab *pVTab);
5555 int (*xDestroy)(sqlite3_vtab *pVTab);
5556 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
5557 int (*xClose)(sqlite3_vtab_cursor*);
5558 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
5559 int argc, sqlite3_value **argv);
5560 int (*xNext)(sqlite3_vtab_cursor*);
5561 int (*xEof)(sqlite3_vtab_cursor*);
5562 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
5563 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
5564 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
5565 int (*xBegin)(sqlite3_vtab *pVTab);
5566 int (*xSync)(sqlite3_vtab *pVTab);
5567 int (*xCommit)(sqlite3_vtab *pVTab);
5568 int (*xRollback)(sqlite3_vtab *pVTab);
5569 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
5570 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
5572 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
5573 /* The methods above are in version 1 of the sqlite_module object. Those
5574 ** below are for version 2 and greater. */
5575 int (*xSavepoint)(sqlite3_vtab *pVTab, int);
5576 int (*xRelease)(sqlite3_vtab *pVTab, int);
5577 int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
5581 ** CAPI3REF: Virtual Table Indexing Information
5582 ** KEYWORDS: sqlite3_index_info
5584 ** The sqlite3_index_info structure and its substructures is used as part
5585 ** of the [virtual table] interface to
5586 ** pass information into and receive the reply from the [xBestIndex]
5587 ** method of a [virtual table module]. The fields under **Inputs** are the
5588 ** inputs to xBestIndex and are read-only. xBestIndex inserts its
5589 ** results into the **Outputs** fields.
5591 ** ^(The aConstraint[] array records WHERE clause constraints of the form:
5593 ** <blockquote>column OP expr</blockquote>
5595 ** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is
5596 ** stored in aConstraint[].op using one of the
5597 ** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
5598 ** ^(The index of the column is stored in
5599 ** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the
5600 ** expr on the right-hand side can be evaluated (and thus the constraint
5601 ** is usable) and false if it cannot.)^
5603 ** ^The optimizer automatically inverts terms of the form "expr OP column"
5604 ** and makes other simplifications to the WHERE clause in an attempt to
5605 ** get as many WHERE clause terms into the form shown above as possible.
5606 ** ^The aConstraint[] array only reports WHERE clause terms that are
5607 ** relevant to the particular virtual table being queried.
5609 ** ^Information about the ORDER BY clause is stored in aOrderBy[].
5610 ** ^Each term of aOrderBy records a column of the ORDER BY clause.
5612 ** The [xBestIndex] method must fill aConstraintUsage[] with information
5613 ** about what parameters to pass to xFilter. ^If argvIndex>0 then
5614 ** the right-hand side of the corresponding aConstraint[] is evaluated
5615 ** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit
5616 ** is true, then the constraint is assumed to be fully handled by the
5617 ** virtual table and is not checked again by SQLite.)^
5619 ** ^The idxNum and idxPtr values are recorded and passed into the
5620 ** [xFilter] method.
5621 ** ^[sqlite3_free()] is used to free idxPtr if and only if
5622 ** needToFreeIdxPtr is true.
5624 ** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
5625 ** the correct order to satisfy the ORDER BY clause so that no separate
5626 ** sorting step is required.
5628 ** ^The estimatedCost value is an estimate of the cost of a particular
5629 ** strategy. A cost of N indicates that the cost of the strategy is similar
5630 ** to a linear scan of an SQLite table with N rows. A cost of log(N)
5631 ** indicates that the expense of the operation is similar to that of a
5632 ** binary search on a unique indexed field of an SQLite table with N rows.
5634 ** ^The estimatedRows value is an estimate of the number of rows that
5635 ** will be returned by the strategy.
5637 ** The xBestIndex method may optionally populate the idxFlags field with a
5638 ** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag -
5639 ** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite
5640 ** assumes that the strategy may visit at most one row.
5642 ** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then
5643 ** SQLite also assumes that if a call to the xUpdate() method is made as
5644 ** part of the same statement to delete or update a virtual table row and the
5645 ** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback
5646 ** any database changes. In other words, if the xUpdate() returns
5647 ** SQLITE_CONSTRAINT, the database contents must be exactly as they were
5648 ** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not
5649 ** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by
5650 ** the xUpdate method are automatically rolled back by SQLite.
5652 ** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info
5653 ** structure for SQLite version 3.8.2. If a virtual table extension is
5654 ** used with an SQLite version earlier than 3.8.2, the results of attempting
5655 ** to read or write the estimatedRows field are undefined (but are likely
5656 ** to included crashing the application). The estimatedRows field should
5657 ** therefore only be used if [sqlite3_libversion_number()] returns a
5658 ** value greater than or equal to 3008002. Similarly, the idxFlags field
5659 ** was added for version 3.9.0. It may therefore only be used if
5660 ** sqlite3_libversion_number() returns a value greater than or equal to
5663 struct sqlite3_index_info {
5665 int nConstraint; /* Number of entries in aConstraint */
5666 struct sqlite3_index_constraint {
5667 int iColumn; /* Column on left-hand side of constraint */
5668 unsigned char op; /* Constraint operator */
5669 unsigned char usable; /* True if this constraint is usable */
5670 int iTermOffset; /* Used internally - xBestIndex should ignore */
5671 } *aConstraint; /* Table of WHERE clause constraints */
5672 int nOrderBy; /* Number of terms in the ORDER BY clause */
5673 struct sqlite3_index_orderby {
5674 int iColumn; /* Column number */
5675 unsigned char desc; /* True for DESC. False for ASC. */
5676 } *aOrderBy; /* The ORDER BY clause */
5678 struct sqlite3_index_constraint_usage {
5679 int argvIndex; /* if >0, constraint is part of argv to xFilter */
5680 unsigned char omit; /* Do not code a test for this constraint */
5681 } *aConstraintUsage;
5682 int idxNum; /* Number used to identify the index */
5683 char *idxStr; /* String, possibly obtained from sqlite3_malloc */
5684 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */
5685 int orderByConsumed; /* True if output is already ordered */
5686 double estimatedCost; /* Estimated cost of using this index */
5687 /* Fields below are only available in SQLite 3.8.2 and later */
5688 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */
5689 /* Fields below are only available in SQLite 3.9.0 and later */
5690 int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */
5694 ** CAPI3REF: Virtual Table Scan Flags
5696 #define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */
5699 ** CAPI3REF: Virtual Table Constraint Operator Codes
5701 ** These macros defined the allowed values for the
5702 ** [sqlite3_index_info].aConstraint[].op field. Each value represents
5703 ** an operator that is part of a constraint term in the wHERE clause of
5704 ** a query that uses a [virtual table].
5706 #define SQLITE_INDEX_CONSTRAINT_EQ 2
5707 #define SQLITE_INDEX_CONSTRAINT_GT 4
5708 #define SQLITE_INDEX_CONSTRAINT_LE 8
5709 #define SQLITE_INDEX_CONSTRAINT_LT 16
5710 #define SQLITE_INDEX_CONSTRAINT_GE 32
5711 #define SQLITE_INDEX_CONSTRAINT_MATCH 64
5714 ** CAPI3REF: Register A Virtual Table Implementation
5717 ** ^These routines are used to register a new [virtual table module] name.
5718 ** ^Module names must be registered before
5719 ** creating a new [virtual table] using the module and before using a
5720 ** preexisting [virtual table] for the module.
5722 ** ^The module name is registered on the [database connection] specified
5723 ** by the first parameter. ^The name of the module is given by the
5724 ** second parameter. ^The third parameter is a pointer to
5725 ** the implementation of the [virtual table module]. ^The fourth
5726 ** parameter is an arbitrary client data pointer that is passed through
5727 ** into the [xCreate] and [xConnect] methods of the virtual table module
5728 ** when a new virtual table is be being created or reinitialized.
5730 ** ^The sqlite3_create_module_v2() interface has a fifth parameter which
5731 ** is a pointer to a destructor for the pClientData. ^SQLite will
5732 ** invoke the destructor function (if it is not NULL) when SQLite
5733 ** no longer needs the pClientData pointer. ^The destructor will also
5734 ** be invoked if the call to sqlite3_create_module_v2() fails.
5735 ** ^The sqlite3_create_module()
5736 ** interface is equivalent to sqlite3_create_module_v2() with a NULL
5739 SQLITE_API int SQLITE_STDCALL sqlite3_create_module(
5740 sqlite3 *db, /* SQLite connection to register module with */
5741 const char *zName, /* Name of the module */
5742 const sqlite3_module *p, /* Methods for the module */
5743 void *pClientData /* Client data for xCreate/xConnect */
5745 SQLITE_API int SQLITE_STDCALL sqlite3_create_module_v2(
5746 sqlite3 *db, /* SQLite connection to register module with */
5747 const char *zName, /* Name of the module */
5748 const sqlite3_module *p, /* Methods for the module */
5749 void *pClientData, /* Client data for xCreate/xConnect */
5750 void(*xDestroy)(void*) /* Module destructor function */
5754 ** CAPI3REF: Virtual Table Instance Object
5755 ** KEYWORDS: sqlite3_vtab
5757 ** Every [virtual table module] implementation uses a subclass
5758 ** of this object to describe a particular instance
5759 ** of the [virtual table]. Each subclass will
5760 ** be tailored to the specific needs of the module implementation.
5761 ** The purpose of this superclass is to define certain fields that are
5762 ** common to all module implementations.
5764 ** ^Virtual tables methods can set an error message by assigning a
5765 ** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should
5766 ** take care that any prior string is freed by a call to [sqlite3_free()]
5767 ** prior to assigning a new string to zErrMsg. ^After the error message
5768 ** is delivered up to the client application, the string will be automatically
5769 ** freed by sqlite3_free() and the zErrMsg field will be zeroed.
5771 struct sqlite3_vtab {
5772 const sqlite3_module *pModule; /* The module for this virtual table */
5773 int nRef; /* Number of open cursors */
5774 char *zErrMsg; /* Error message from sqlite3_mprintf() */
5775 /* Virtual table implementations will typically add additional fields */
5779 ** CAPI3REF: Virtual Table Cursor Object
5780 ** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
5782 ** Every [virtual table module] implementation uses a subclass of the
5783 ** following structure to describe cursors that point into the
5784 ** [virtual table] and are used
5785 ** to loop through the virtual table. Cursors are created using the
5786 ** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
5787 ** by the [sqlite3_module.xClose | xClose] method. Cursors are used
5788 ** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
5789 ** of the module. Each module implementation will define
5790 ** the content of a cursor structure to suit its own needs.
5792 ** This superclass exists in order to define fields of the cursor that
5793 ** are common to all implementations.
5795 struct sqlite3_vtab_cursor {
5796 sqlite3_vtab *pVtab; /* Virtual table of this cursor */
5797 /* Virtual table implementations will typically add additional fields */
5801 ** CAPI3REF: Declare The Schema Of A Virtual Table
5803 ** ^The [xCreate] and [xConnect] methods of a
5804 ** [virtual table module] call this interface
5805 ** to declare the format (the names and datatypes of the columns) of
5806 ** the virtual tables they implement.
5808 SQLITE_API int SQLITE_STDCALL sqlite3_declare_vtab(sqlite3*, const char *zSQL);
5811 ** CAPI3REF: Overload A Function For A Virtual Table
5814 ** ^(Virtual tables can provide alternative implementations of functions
5815 ** using the [xFindFunction] method of the [virtual table module].
5816 ** But global versions of those functions
5817 ** must exist in order to be overloaded.)^
5819 ** ^(This API makes sure a global version of a function with a particular
5820 ** name and number of parameters exists. If no such function exists
5821 ** before this API is called, a new function is created.)^ ^The implementation
5822 ** of the new function always causes an exception to be thrown. So
5823 ** the new function is not good for anything by itself. Its only
5824 ** purpose is to be a placeholder function that can be overloaded
5825 ** by a [virtual table].
5827 SQLITE_API int SQLITE_STDCALL sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
5830 ** The interface to the virtual-table mechanism defined above (back up
5831 ** to a comment remarkably similar to this one) is currently considered
5832 ** to be experimental. The interface might change in incompatible ways.
5833 ** If this is a problem for you, do not use the interface at this time.
5835 ** When the virtual-table mechanism stabilizes, we will declare the
5836 ** interface fixed, support it indefinitely, and remove this comment.
5840 ** CAPI3REF: A Handle To An Open BLOB
5841 ** KEYWORDS: {BLOB handle} {BLOB handles}
5843 ** An instance of this object represents an open BLOB on which
5844 ** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
5845 ** ^Objects of this type are created by [sqlite3_blob_open()]
5846 ** and destroyed by [sqlite3_blob_close()].
5847 ** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
5848 ** can be used to read or write small subsections of the BLOB.
5849 ** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
5851 typedef struct sqlite3_blob sqlite3_blob;
5854 ** CAPI3REF: Open A BLOB For Incremental I/O
5856 ** CONSTRUCTOR: sqlite3_blob
5858 ** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
5859 ** in row iRow, column zColumn, table zTable in database zDb;
5860 ** in other words, the same BLOB that would be selected by:
5863 ** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
5866 ** ^(Parameter zDb is not the filename that contains the database, but
5867 ** rather the symbolic name of the database. For attached databases, this is
5868 ** the name that appears after the AS keyword in the [ATTACH] statement.
5869 ** For the main database file, the database name is "main". For TEMP
5870 ** tables, the database name is "temp".)^
5872 ** ^If the flags parameter is non-zero, then the BLOB is opened for read
5873 ** and write access. ^If the flags parameter is zero, the BLOB is opened for
5874 ** read-only access.
5876 ** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored
5877 ** in *ppBlob. Otherwise an [error code] is returned and, unless the error
5878 ** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided
5879 ** the API is not misused, it is always safe to call [sqlite3_blob_close()]
5880 ** on *ppBlob after this function it returns.
5882 ** This function fails with SQLITE_ERROR if any of the following are true:
5884 ** <li> ^(Database zDb does not exist)^,
5885 ** <li> ^(Table zTable does not exist within database zDb)^,
5886 ** <li> ^(Table zTable is a WITHOUT ROWID table)^,
5887 ** <li> ^(Column zColumn does not exist)^,
5888 ** <li> ^(Row iRow is not present in the table)^,
5889 ** <li> ^(The specified column of row iRow contains a value that is not
5890 ** a TEXT or BLOB value)^,
5891 ** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE
5892 ** constraint and the blob is being opened for read/write access)^,
5893 ** <li> ^([foreign key constraints | Foreign key constraints] are enabled,
5894 ** column zColumn is part of a [child key] definition and the blob is
5895 ** being opened for read/write access)^.
5898 ** ^Unless it returns SQLITE_MISUSE, this function sets the
5899 ** [database connection] error code and message accessible via
5900 ** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
5903 ** ^(If the row that a BLOB handle points to is modified by an
5904 ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
5905 ** then the BLOB handle is marked as "expired".
5906 ** This is true if any column of the row is changed, even a column
5907 ** other than the one the BLOB handle is open on.)^
5908 ** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
5909 ** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
5910 ** ^(Changes written into a BLOB prior to the BLOB expiring are not
5911 ** rolled back by the expiration of the BLOB. Such changes will eventually
5912 ** commit if the transaction continues to completion.)^
5914 ** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
5915 ** the opened blob. ^The size of a blob may not be changed by this
5916 ** interface. Use the [UPDATE] SQL command to change the size of a
5919 ** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
5920 ** and the built-in [zeroblob] SQL function may be used to create a
5921 ** zero-filled blob to read or write using the incremental-blob interface.
5923 ** To avoid a resource leak, every open [BLOB handle] should eventually
5924 ** be released by a call to [sqlite3_blob_close()].
5926 SQLITE_API int SQLITE_STDCALL sqlite3_blob_open(
5930 const char *zColumn,
5933 sqlite3_blob **ppBlob
5937 ** CAPI3REF: Move a BLOB Handle to a New Row
5938 ** METHOD: sqlite3_blob
5940 ** ^This function is used to move an existing blob handle so that it points
5941 ** to a different row of the same database table. ^The new row is identified
5942 ** by the rowid value passed as the second argument. Only the row can be
5943 ** changed. ^The database, table and column on which the blob handle is open
5944 ** remain the same. Moving an existing blob handle to a new row can be
5945 ** faster than closing the existing handle and opening a new one.
5947 ** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
5948 ** it must exist and there must be either a blob or text value stored in
5949 ** the nominated column.)^ ^If the new row is not present in the table, or if
5950 ** it does not contain a blob or text value, or if another error occurs, an
5951 ** SQLite error code is returned and the blob handle is considered aborted.
5952 ** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
5953 ** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
5954 ** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
5955 ** always returns zero.
5957 ** ^This function sets the database handle error code and message.
5959 SQLITE_API int SQLITE_STDCALL sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
5962 ** CAPI3REF: Close A BLOB Handle
5963 ** DESTRUCTOR: sqlite3_blob
5965 ** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed
5966 ** unconditionally. Even if this routine returns an error code, the
5967 ** handle is still closed.)^
5969 ** ^If the blob handle being closed was opened for read-write access, and if
5970 ** the database is in auto-commit mode and there are no other open read-write
5971 ** blob handles or active write statements, the current transaction is
5972 ** committed. ^If an error occurs while committing the transaction, an error
5973 ** code is returned and the transaction rolled back.
5975 ** Calling this function with an argument that is not a NULL pointer or an
5976 ** open blob handle results in undefined behaviour. ^Calling this routine
5977 ** with a null pointer (such as would be returned by a failed call to
5978 ** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function
5979 ** is passed a valid open blob handle, the values returned by the
5980 ** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning.
5982 SQLITE_API int SQLITE_STDCALL sqlite3_blob_close(sqlite3_blob *);
5985 ** CAPI3REF: Return The Size Of An Open BLOB
5986 ** METHOD: sqlite3_blob
5988 ** ^Returns the size in bytes of the BLOB accessible via the
5989 ** successfully opened [BLOB handle] in its only argument. ^The
5990 ** incremental blob I/O routines can only read or overwriting existing
5991 ** blob content; they cannot change the size of a blob.
5993 ** This routine only works on a [BLOB handle] which has been created
5994 ** by a prior successful call to [sqlite3_blob_open()] and which has not
5995 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
5996 ** to this routine results in undefined and probably undesirable behavior.
5998 SQLITE_API int SQLITE_STDCALL sqlite3_blob_bytes(sqlite3_blob *);
6001 ** CAPI3REF: Read Data From A BLOB Incrementally
6002 ** METHOD: sqlite3_blob
6004 ** ^(This function is used to read data from an open [BLOB handle] into a
6005 ** caller-supplied buffer. N bytes of data are copied into buffer Z
6006 ** from the open BLOB, starting at offset iOffset.)^
6008 ** ^If offset iOffset is less than N bytes from the end of the BLOB,
6009 ** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is
6010 ** less than zero, [SQLITE_ERROR] is returned and no data is read.
6011 ** ^The size of the blob (and hence the maximum value of N+iOffset)
6012 ** can be determined using the [sqlite3_blob_bytes()] interface.
6014 ** ^An attempt to read from an expired [BLOB handle] fails with an
6015 ** error code of [SQLITE_ABORT].
6017 ** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
6018 ** Otherwise, an [error code] or an [extended error code] is returned.)^
6020 ** This routine only works on a [BLOB handle] which has been created
6021 ** by a prior successful call to [sqlite3_blob_open()] and which has not
6022 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
6023 ** to this routine results in undefined and probably undesirable behavior.
6025 ** See also: [sqlite3_blob_write()].
6027 SQLITE_API int SQLITE_STDCALL sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
6030 ** CAPI3REF: Write Data Into A BLOB Incrementally
6031 ** METHOD: sqlite3_blob
6033 ** ^(This function is used to write data into an open [BLOB handle] from a
6034 ** caller-supplied buffer. N bytes of data are copied from the buffer Z
6035 ** into the open BLOB, starting at offset iOffset.)^
6037 ** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
6038 ** Otherwise, an [error code] or an [extended error code] is returned.)^
6039 ** ^Unless SQLITE_MISUSE is returned, this function sets the
6040 ** [database connection] error code and message accessible via
6041 ** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
6043 ** ^If the [BLOB handle] passed as the first argument was not opened for
6044 ** writing (the flags parameter to [sqlite3_blob_open()] was zero),
6045 ** this function returns [SQLITE_READONLY].
6047 ** This function may only modify the contents of the BLOB; it is
6048 ** not possible to increase the size of a BLOB using this API.
6049 ** ^If offset iOffset is less than N bytes from the end of the BLOB,
6050 ** [SQLITE_ERROR] is returned and no data is written. The size of the
6051 ** BLOB (and hence the maximum value of N+iOffset) can be determined
6052 ** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less
6053 ** than zero [SQLITE_ERROR] is returned and no data is written.
6055 ** ^An attempt to write to an expired [BLOB handle] fails with an
6056 ** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred
6057 ** before the [BLOB handle] expired are not rolled back by the
6058 ** expiration of the handle, though of course those changes might
6059 ** have been overwritten by the statement that expired the BLOB handle
6060 ** or by other independent statements.
6062 ** This routine only works on a [BLOB handle] which has been created
6063 ** by a prior successful call to [sqlite3_blob_open()] and which has not
6064 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
6065 ** to this routine results in undefined and probably undesirable behavior.
6067 ** See also: [sqlite3_blob_read()].
6069 SQLITE_API int SQLITE_STDCALL sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
6072 ** CAPI3REF: Virtual File System Objects
6074 ** A virtual filesystem (VFS) is an [sqlite3_vfs] object
6075 ** that SQLite uses to interact
6076 ** with the underlying operating system. Most SQLite builds come with a
6077 ** single default VFS that is appropriate for the host computer.
6078 ** New VFSes can be registered and existing VFSes can be unregistered.
6079 ** The following interfaces are provided.
6081 ** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
6082 ** ^Names are case sensitive.
6083 ** ^Names are zero-terminated UTF-8 strings.
6084 ** ^If there is no match, a NULL pointer is returned.
6085 ** ^If zVfsName is NULL then the default VFS is returned.
6087 ** ^New VFSes are registered with sqlite3_vfs_register().
6088 ** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
6089 ** ^The same VFS can be registered multiple times without injury.
6090 ** ^To make an existing VFS into the default VFS, register it again
6091 ** with the makeDflt flag set. If two different VFSes with the
6092 ** same name are registered, the behavior is undefined. If a
6093 ** VFS is registered with a name that is NULL or an empty string,
6094 ** then the behavior is undefined.
6096 ** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
6097 ** ^(If the default VFS is unregistered, another VFS is chosen as
6098 ** the default. The choice for the new VFS is arbitrary.)^
6100 SQLITE_API sqlite3_vfs *SQLITE_STDCALL sqlite3_vfs_find(const char *zVfsName);
6101 SQLITE_API int SQLITE_STDCALL sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
6102 SQLITE_API int SQLITE_STDCALL sqlite3_vfs_unregister(sqlite3_vfs*);
6105 ** CAPI3REF: Mutexes
6107 ** The SQLite core uses these routines for thread
6108 ** synchronization. Though they are intended for internal
6109 ** use by SQLite, code that links against SQLite is
6110 ** permitted to use any of these routines.
6112 ** The SQLite source code contains multiple implementations
6113 ** of these mutex routines. An appropriate implementation
6114 ** is selected automatically at compile-time. The following
6115 ** implementations are available in the SQLite core:
6118 ** <li> SQLITE_MUTEX_PTHREADS
6119 ** <li> SQLITE_MUTEX_W32
6120 ** <li> SQLITE_MUTEX_NOOP
6123 ** The SQLITE_MUTEX_NOOP implementation is a set of routines
6124 ** that does no real locking and is appropriate for use in
6125 ** a single-threaded application. The SQLITE_MUTEX_PTHREADS and
6126 ** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
6129 ** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
6130 ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
6131 ** implementation is included with the library. In this case the
6132 ** application must supply a custom mutex implementation using the
6133 ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
6134 ** before calling sqlite3_initialize() or any other public sqlite3_
6135 ** function that calls sqlite3_initialize().
6137 ** ^The sqlite3_mutex_alloc() routine allocates a new
6138 ** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc()
6139 ** routine returns NULL if it is unable to allocate the requested
6140 ** mutex. The argument to sqlite3_mutex_alloc() must one of these
6141 ** integer constants:
6144 ** <li> SQLITE_MUTEX_FAST
6145 ** <li> SQLITE_MUTEX_RECURSIVE
6146 ** <li> SQLITE_MUTEX_STATIC_MASTER
6147 ** <li> SQLITE_MUTEX_STATIC_MEM
6148 ** <li> SQLITE_MUTEX_STATIC_OPEN
6149 ** <li> SQLITE_MUTEX_STATIC_PRNG
6150 ** <li> SQLITE_MUTEX_STATIC_LRU
6151 ** <li> SQLITE_MUTEX_STATIC_PMEM
6152 ** <li> SQLITE_MUTEX_STATIC_APP1
6153 ** <li> SQLITE_MUTEX_STATIC_APP2
6154 ** <li> SQLITE_MUTEX_STATIC_APP3
6155 ** <li> SQLITE_MUTEX_STATIC_VFS1
6156 ** <li> SQLITE_MUTEX_STATIC_VFS2
6157 ** <li> SQLITE_MUTEX_STATIC_VFS3
6160 ** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
6161 ** cause sqlite3_mutex_alloc() to create
6162 ** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
6163 ** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
6164 ** The mutex implementation does not need to make a distinction
6165 ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
6166 ** not want to. SQLite will only request a recursive mutex in
6167 ** cases where it really needs one. If a faster non-recursive mutex
6168 ** implementation is available on the host platform, the mutex subsystem
6169 ** might return such a mutex in response to SQLITE_MUTEX_FAST.
6171 ** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
6172 ** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
6173 ** a pointer to a static preexisting mutex. ^Nine static mutexes are
6174 ** used by the current version of SQLite. Future versions of SQLite
6175 ** may add additional static mutexes. Static mutexes are for internal
6176 ** use by SQLite only. Applications that use SQLite mutexes should
6177 ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
6178 ** SQLITE_MUTEX_RECURSIVE.
6180 ** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
6181 ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
6182 ** returns a different mutex on every call. ^For the static
6183 ** mutex types, the same mutex is returned on every call that has
6184 ** the same type number.
6186 ** ^The sqlite3_mutex_free() routine deallocates a previously
6187 ** allocated dynamic mutex. Attempting to deallocate a static
6188 ** mutex results in undefined behavior.
6190 ** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
6191 ** to enter a mutex. ^If another thread is already within the mutex,
6192 ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
6193 ** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
6194 ** upon successful entry. ^(Mutexes created using
6195 ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
6196 ** In such cases, the
6197 ** mutex must be exited an equal number of times before another thread
6198 ** can enter.)^ If the same thread tries to enter any mutex other
6199 ** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined.
6201 ** ^(Some systems (for example, Windows 95) do not support the operation
6202 ** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try()
6203 ** will always return SQLITE_BUSY. The SQLite core only ever uses
6204 ** sqlite3_mutex_try() as an optimization so this is acceptable
6207 ** ^The sqlite3_mutex_leave() routine exits a mutex that was
6208 ** previously entered by the same thread. The behavior
6209 ** is undefined if the mutex is not currently entered by the
6210 ** calling thread or is not currently allocated.
6212 ** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
6213 ** sqlite3_mutex_leave() is a NULL pointer, then all three routines
6214 ** behave as no-ops.
6216 ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
6218 SQLITE_API sqlite3_mutex *SQLITE_STDCALL sqlite3_mutex_alloc(int);
6219 SQLITE_API void SQLITE_STDCALL sqlite3_mutex_free(sqlite3_mutex*);
6220 SQLITE_API void SQLITE_STDCALL sqlite3_mutex_enter(sqlite3_mutex*);
6221 SQLITE_API int SQLITE_STDCALL sqlite3_mutex_try(sqlite3_mutex*);
6222 SQLITE_API void SQLITE_STDCALL sqlite3_mutex_leave(sqlite3_mutex*);
6225 ** CAPI3REF: Mutex Methods Object
6227 ** An instance of this structure defines the low-level routines
6228 ** used to allocate and use mutexes.
6230 ** Usually, the default mutex implementations provided by SQLite are
6231 ** sufficient, however the application has the option of substituting a custom
6232 ** implementation for specialized deployments or systems for which SQLite
6233 ** does not provide a suitable implementation. In this case, the application
6234 ** creates and populates an instance of this structure to pass
6235 ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
6236 ** Additionally, an instance of this structure can be used as an
6237 ** output variable when querying the system for the current mutex
6238 ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
6240 ** ^The xMutexInit method defined by this structure is invoked as
6241 ** part of system initialization by the sqlite3_initialize() function.
6242 ** ^The xMutexInit routine is called by SQLite exactly once for each
6243 ** effective call to [sqlite3_initialize()].
6245 ** ^The xMutexEnd method defined by this structure is invoked as
6246 ** part of system shutdown by the sqlite3_shutdown() function. The
6247 ** implementation of this method is expected to release all outstanding
6248 ** resources obtained by the mutex methods implementation, especially
6249 ** those obtained by the xMutexInit method. ^The xMutexEnd()
6250 ** interface is invoked exactly once for each call to [sqlite3_shutdown()].
6252 ** ^(The remaining seven methods defined by this structure (xMutexAlloc,
6253 ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
6254 ** xMutexNotheld) implement the following interfaces (respectively):
6257 ** <li> [sqlite3_mutex_alloc()] </li>
6258 ** <li> [sqlite3_mutex_free()] </li>
6259 ** <li> [sqlite3_mutex_enter()] </li>
6260 ** <li> [sqlite3_mutex_try()] </li>
6261 ** <li> [sqlite3_mutex_leave()] </li>
6262 ** <li> [sqlite3_mutex_held()] </li>
6263 ** <li> [sqlite3_mutex_notheld()] </li>
6266 ** The only difference is that the public sqlite3_XXX functions enumerated
6267 ** above silently ignore any invocations that pass a NULL pointer instead
6268 ** of a valid mutex handle. The implementations of the methods defined
6269 ** by this structure are not required to handle this case, the results
6270 ** of passing a NULL pointer instead of a valid mutex handle are undefined
6271 ** (i.e. it is acceptable to provide an implementation that segfaults if
6272 ** it is passed a NULL pointer).
6274 ** The xMutexInit() method must be threadsafe. It must be harmless to
6275 ** invoke xMutexInit() multiple times within the same process and without
6276 ** intervening calls to xMutexEnd(). Second and subsequent calls to
6277 ** xMutexInit() must be no-ops.
6279 ** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
6280 ** and its associates). Similarly, xMutexAlloc() must not use SQLite memory
6281 ** allocation for a static mutex. ^However xMutexAlloc() may use SQLite
6282 ** memory allocation for a fast or recursive mutex.
6284 ** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
6285 ** called, but only if the prior call to xMutexInit returned SQLITE_OK.
6286 ** If xMutexInit fails in any way, it is expected to clean up after itself
6287 ** prior to returning.
6289 typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
6290 struct sqlite3_mutex_methods {
6291 int (*xMutexInit)(void);
6292 int (*xMutexEnd)(void);
6293 sqlite3_mutex *(*xMutexAlloc)(int);
6294 void (*xMutexFree)(sqlite3_mutex *);
6295 void (*xMutexEnter)(sqlite3_mutex *);
6296 int (*xMutexTry)(sqlite3_mutex *);
6297 void (*xMutexLeave)(sqlite3_mutex *);
6298 int (*xMutexHeld)(sqlite3_mutex *);
6299 int (*xMutexNotheld)(sqlite3_mutex *);
6303 ** CAPI3REF: Mutex Verification Routines
6305 ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
6306 ** are intended for use inside assert() statements. The SQLite core
6307 ** never uses these routines except inside an assert() and applications
6308 ** are advised to follow the lead of the core. The SQLite core only
6309 ** provides implementations for these routines when it is compiled
6310 ** with the SQLITE_DEBUG flag. External mutex implementations
6311 ** are only required to provide these routines if SQLITE_DEBUG is
6312 ** defined and if NDEBUG is not defined.
6314 ** These routines should return true if the mutex in their argument
6315 ** is held or not held, respectively, by the calling thread.
6317 ** The implementation is not required to provide versions of these
6318 ** routines that actually work. If the implementation does not provide working
6319 ** versions of these routines, it should at least provide stubs that always
6320 ** return true so that one does not get spurious assertion failures.
6322 ** If the argument to sqlite3_mutex_held() is a NULL pointer then
6323 ** the routine should return 1. This seems counter-intuitive since
6324 ** clearly the mutex cannot be held if it does not exist. But
6325 ** the reason the mutex does not exist is because the build is not
6326 ** using mutexes. And we do not want the assert() containing the
6327 ** call to sqlite3_mutex_held() to fail, so a non-zero return is
6328 ** the appropriate thing to do. The sqlite3_mutex_notheld()
6329 ** interface should also return 1 when given a NULL pointer.
6332 SQLITE_API int SQLITE_STDCALL sqlite3_mutex_held(sqlite3_mutex*);
6333 SQLITE_API int SQLITE_STDCALL sqlite3_mutex_notheld(sqlite3_mutex*);
6337 ** CAPI3REF: Mutex Types
6339 ** The [sqlite3_mutex_alloc()] interface takes a single argument
6340 ** which is one of these integer constants.
6342 ** The set of static mutexes may change from one SQLite release to the
6343 ** next. Applications that override the built-in mutex logic must be
6344 ** prepared to accommodate additional static mutexes.
6346 #define SQLITE_MUTEX_FAST 0
6347 #define SQLITE_MUTEX_RECURSIVE 1
6348 #define SQLITE_MUTEX_STATIC_MASTER 2
6349 #define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */
6350 #define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */
6351 #define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */
6352 #define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */
6353 #define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */
6354 #define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */
6355 #define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */
6356 #define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */
6357 #define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */
6358 #define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */
6359 #define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */
6360 #define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */
6361 #define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */
6364 ** CAPI3REF: Retrieve the mutex for a database connection
6367 ** ^This interface returns a pointer the [sqlite3_mutex] object that
6368 ** serializes access to the [database connection] given in the argument
6369 ** when the [threading mode] is Serialized.
6370 ** ^If the [threading mode] is Single-thread or Multi-thread then this
6371 ** routine returns a NULL pointer.
6373 SQLITE_API sqlite3_mutex *SQLITE_STDCALL sqlite3_db_mutex(sqlite3*);
6376 ** CAPI3REF: Low-Level Control Of Database Files
6379 ** ^The [sqlite3_file_control()] interface makes a direct call to the
6380 ** xFileControl method for the [sqlite3_io_methods] object associated
6381 ** with a particular database identified by the second argument. ^The
6382 ** name of the database is "main" for the main database or "temp" for the
6383 ** TEMP database, or the name that appears after the AS keyword for
6384 ** databases that are added using the [ATTACH] SQL command.
6385 ** ^A NULL pointer can be used in place of "main" to refer to the
6386 ** main database file.
6387 ** ^The third and fourth parameters to this routine
6388 ** are passed directly through to the second and third parameters of
6389 ** the xFileControl method. ^The return value of the xFileControl
6390 ** method becomes the return value of this routine.
6392 ** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes
6393 ** a pointer to the underlying [sqlite3_file] object to be written into
6394 ** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER
6395 ** case is a short-circuit path which does not actually invoke the
6396 ** underlying sqlite3_io_methods.xFileControl method.
6398 ** ^If the second parameter (zDbName) does not match the name of any
6399 ** open database file, then SQLITE_ERROR is returned. ^This error
6400 ** code is not remembered and will not be recalled by [sqlite3_errcode()]
6401 ** or [sqlite3_errmsg()]. The underlying xFileControl method might
6402 ** also return SQLITE_ERROR. There is no way to distinguish between
6403 ** an incorrect zDbName and an SQLITE_ERROR return from the underlying
6404 ** xFileControl method.
6406 ** See also: [SQLITE_FCNTL_LOCKSTATE]
6408 SQLITE_API int SQLITE_STDCALL sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
6411 ** CAPI3REF: Testing Interface
6413 ** ^The sqlite3_test_control() interface is used to read out internal
6414 ** state of SQLite and to inject faults into SQLite for testing
6415 ** purposes. ^The first parameter is an operation code that determines
6416 ** the number, meaning, and operation of all subsequent parameters.
6418 ** This interface is not for use by applications. It exists solely
6419 ** for verifying the correct operation of the SQLite library. Depending
6420 ** on how the SQLite library is compiled, this interface might not exist.
6422 ** The details of the operation codes, their meanings, the parameters
6423 ** they take, and what they do are all subject to change without notice.
6424 ** Unlike most of the SQLite API, this function is not guaranteed to
6425 ** operate consistently from one release to the next.
6427 SQLITE_API int SQLITE_CDECL sqlite3_test_control(int op, ...);
6430 ** CAPI3REF: Testing Interface Operation Codes
6432 ** These constants are the valid operation code parameters used
6433 ** as the first argument to [sqlite3_test_control()].
6435 ** These parameters and their meanings are subject to change
6436 ** without notice. These values are for testing purposes only.
6437 ** Applications should not use any of these parameters or the
6438 ** [sqlite3_test_control()] interface.
6440 #define SQLITE_TESTCTRL_FIRST 5
6441 #define SQLITE_TESTCTRL_PRNG_SAVE 5
6442 #define SQLITE_TESTCTRL_PRNG_RESTORE 6
6443 #define SQLITE_TESTCTRL_PRNG_RESET 7
6444 #define SQLITE_TESTCTRL_BITVEC_TEST 8
6445 #define SQLITE_TESTCTRL_FAULT_INSTALL 9
6446 #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10
6447 #define SQLITE_TESTCTRL_PENDING_BYTE 11
6448 #define SQLITE_TESTCTRL_ASSERT 12
6449 #define SQLITE_TESTCTRL_ALWAYS 13
6450 #define SQLITE_TESTCTRL_RESERVE 14
6451 #define SQLITE_TESTCTRL_OPTIMIZATIONS 15
6452 #define SQLITE_TESTCTRL_ISKEYWORD 16
6453 #define SQLITE_TESTCTRL_SCRATCHMALLOC 17
6454 #define SQLITE_TESTCTRL_LOCALTIME_FAULT 18
6455 #define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */
6456 #define SQLITE_TESTCTRL_NEVER_CORRUPT 20
6457 #define SQLITE_TESTCTRL_VDBE_COVERAGE 21
6458 #define SQLITE_TESTCTRL_BYTEORDER 22
6459 #define SQLITE_TESTCTRL_ISINIT 23
6460 #define SQLITE_TESTCTRL_SORTER_MMAP 24
6461 #define SQLITE_TESTCTRL_IMPOSTER 25
6462 #define SQLITE_TESTCTRL_LAST 25
6465 ** CAPI3REF: SQLite Runtime Status
6467 ** ^These interfaces are used to retrieve runtime status information
6468 ** about the performance of SQLite, and optionally to reset various
6469 ** highwater marks. ^The first argument is an integer code for
6470 ** the specific parameter to measure. ^(Recognized integer codes
6471 ** are of the form [status parameters | SQLITE_STATUS_...].)^
6472 ** ^The current value of the parameter is returned into *pCurrent.
6473 ** ^The highest recorded value is returned in *pHighwater. ^If the
6474 ** resetFlag is true, then the highest record value is reset after
6475 ** *pHighwater is written. ^(Some parameters do not record the highest
6476 ** value. For those parameters
6477 ** nothing is written into *pHighwater and the resetFlag is ignored.)^
6478 ** ^(Other parameters record only the highwater mark and not the current
6479 ** value. For these latter parameters nothing is written into *pCurrent.)^
6481 ** ^The sqlite3_status() and sqlite3_status64() routines return
6482 ** SQLITE_OK on success and a non-zero [error code] on failure.
6484 ** If either the current value or the highwater mark is too large to
6485 ** be represented by a 32-bit integer, then the values returned by
6486 ** sqlite3_status() are undefined.
6488 ** See also: [sqlite3_db_status()]
6490 SQLITE_API int SQLITE_STDCALL sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
6491 SQLITE_API int SQLITE_STDCALL sqlite3_status64(
6493 sqlite3_int64 *pCurrent,
6494 sqlite3_int64 *pHighwater,
6500 ** CAPI3REF: Status Parameters
6501 ** KEYWORDS: {status parameters}
6503 ** These integer constants designate various run-time status parameters
6504 ** that can be returned by [sqlite3_status()].
6507 ** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
6508 ** <dd>This parameter is the current amount of memory checked out
6509 ** using [sqlite3_malloc()], either directly or indirectly. The
6510 ** figure includes calls made to [sqlite3_malloc()] by the application
6511 ** and internal memory usage by the SQLite library. Scratch memory
6512 ** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache
6513 ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
6514 ** this parameter. The amount returned is the sum of the allocation
6515 ** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
6517 ** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
6518 ** <dd>This parameter records the largest memory allocation request
6519 ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
6520 ** internal equivalents). Only the value returned in the
6521 ** *pHighwater parameter to [sqlite3_status()] is of interest.
6522 ** The value written into the *pCurrent parameter is undefined.</dd>)^
6524 ** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
6525 ** <dd>This parameter records the number of separate memory allocations
6526 ** currently checked out.</dd>)^
6528 ** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
6529 ** <dd>This parameter returns the number of pages used out of the
6530 ** [pagecache memory allocator] that was configured using
6531 ** [SQLITE_CONFIG_PAGECACHE]. The
6532 ** value returned is in pages, not in bytes.</dd>)^
6534 ** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]]
6535 ** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
6536 ** <dd>This parameter returns the number of bytes of page cache
6537 ** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
6538 ** buffer and where forced to overflow to [sqlite3_malloc()]. The
6539 ** returned value includes allocations that overflowed because they
6540 ** where too large (they were larger than the "sz" parameter to
6541 ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
6542 ** no space was left in the page cache.</dd>)^
6544 ** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
6545 ** <dd>This parameter records the largest memory allocation request
6546 ** handed to [pagecache memory allocator]. Only the value returned in the
6547 ** *pHighwater parameter to [sqlite3_status()] is of interest.
6548 ** The value written into the *pCurrent parameter is undefined.</dd>)^
6550 ** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt>
6551 ** <dd>This parameter returns the number of allocations used out of the
6552 ** [scratch memory allocator] configured using
6553 ** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not
6554 ** in bytes. Since a single thread may only have one scratch allocation
6555 ** outstanding at time, this parameter also reports the number of threads
6556 ** using scratch memory at the same time.</dd>)^
6558 ** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
6559 ** <dd>This parameter returns the number of bytes of scratch memory
6560 ** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH]
6561 ** buffer and where forced to overflow to [sqlite3_malloc()]. The values
6562 ** returned include overflows because the requested allocation was too
6563 ** larger (that is, because the requested allocation was larger than the
6564 ** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer
6565 ** slots were available.
6568 ** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
6569 ** <dd>This parameter records the largest memory allocation request
6570 ** handed to [scratch memory allocator]. Only the value returned in the
6571 ** *pHighwater parameter to [sqlite3_status()] is of interest.
6572 ** The value written into the *pCurrent parameter is undefined.</dd>)^
6574 ** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
6575 ** <dd>This parameter records the deepest parser stack. It is only
6576 ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
6579 ** New status parameters may be added from time to time.
6581 #define SQLITE_STATUS_MEMORY_USED 0
6582 #define SQLITE_STATUS_PAGECACHE_USED 1
6583 #define SQLITE_STATUS_PAGECACHE_OVERFLOW 2
6584 #define SQLITE_STATUS_SCRATCH_USED 3
6585 #define SQLITE_STATUS_SCRATCH_OVERFLOW 4
6586 #define SQLITE_STATUS_MALLOC_SIZE 5
6587 #define SQLITE_STATUS_PARSER_STACK 6
6588 #define SQLITE_STATUS_PAGECACHE_SIZE 7
6589 #define SQLITE_STATUS_SCRATCH_SIZE 8
6590 #define SQLITE_STATUS_MALLOC_COUNT 9
6593 ** CAPI3REF: Database Connection Status
6596 ** ^This interface is used to retrieve runtime status information
6597 ** about a single [database connection]. ^The first argument is the
6598 ** database connection object to be interrogated. ^The second argument
6599 ** is an integer constant, taken from the set of
6600 ** [SQLITE_DBSTATUS options], that
6601 ** determines the parameter to interrogate. The set of
6602 ** [SQLITE_DBSTATUS options] is likely
6603 ** to grow in future releases of SQLite.
6605 ** ^The current value of the requested parameter is written into *pCur
6606 ** and the highest instantaneous value is written into *pHiwtr. ^If
6607 ** the resetFlg is true, then the highest instantaneous value is
6608 ** reset back down to the current value.
6610 ** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
6611 ** non-zero [error code] on failure.
6613 ** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
6615 SQLITE_API int SQLITE_STDCALL sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
6618 ** CAPI3REF: Status Parameters for database connections
6619 ** KEYWORDS: {SQLITE_DBSTATUS options}
6621 ** These constants are the available integer "verbs" that can be passed as
6622 ** the second argument to the [sqlite3_db_status()] interface.
6624 ** New verbs may be added in future releases of SQLite. Existing verbs
6625 ** might be discontinued. Applications should check the return code from
6626 ** [sqlite3_db_status()] to make sure that the call worked.
6627 ** The [sqlite3_db_status()] interface will return a non-zero error code
6628 ** if a discontinued or unsupported verb is invoked.
6631 ** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
6632 ** <dd>This parameter returns the number of lookaside memory slots currently
6633 ** checked out.</dd>)^
6635 ** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
6636 ** <dd>This parameter returns the number malloc attempts that were
6637 ** satisfied using lookaside memory. Only the high-water value is meaningful;
6638 ** the current value is always zero.)^
6640 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]]
6641 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
6642 ** <dd>This parameter returns the number malloc attempts that might have
6643 ** been satisfied using lookaside memory but failed due to the amount of
6644 ** memory requested being larger than the lookaside slot size.
6645 ** Only the high-water value is meaningful;
6646 ** the current value is always zero.)^
6648 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]]
6649 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
6650 ** <dd>This parameter returns the number malloc attempts that might have
6651 ** been satisfied using lookaside memory but failed due to all lookaside
6652 ** memory already being in use.
6653 ** Only the high-water value is meaningful;
6654 ** the current value is always zero.)^
6656 ** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
6657 ** <dd>This parameter returns the approximate number of bytes of heap
6658 ** memory used by all pager caches associated with the database connection.)^
6659 ** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
6661 ** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
6662 ** <dd>This parameter returns the approximate number of bytes of heap
6663 ** memory used to store the schema for all databases associated
6664 ** with the connection - main, temp, and any [ATTACH]-ed databases.)^
6665 ** ^The full amount of memory used by the schemas is reported, even if the
6666 ** schema memory is shared with other database connections due to
6667 ** [shared cache mode] being enabled.
6668 ** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
6670 ** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
6671 ** <dd>This parameter returns the approximate number of bytes of heap
6672 ** and lookaside memory used by all prepared statements associated with
6673 ** the database connection.)^
6674 ** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
6677 ** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt>
6678 ** <dd>This parameter returns the number of pager cache hits that have
6679 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT
6683 ** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt>
6684 ** <dd>This parameter returns the number of pager cache misses that have
6685 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS
6689 ** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt>
6690 ** <dd>This parameter returns the number of dirty cache entries that have
6691 ** been written to disk. Specifically, the number of pages written to the
6692 ** wal file in wal mode databases, or the number of pages written to the
6693 ** database file in rollback mode databases. Any pages written as part of
6694 ** transaction rollback or database recovery operations are not included.
6695 ** If an IO or other error occurs while writing a page to disk, the effect
6696 ** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The
6697 ** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0.
6700 ** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt>
6701 ** <dd>This parameter returns zero for the current value if and only if
6702 ** all foreign key constraints (deferred or immediate) have been
6703 ** resolved.)^ ^The highwater mark is always 0.
6707 #define SQLITE_DBSTATUS_LOOKASIDE_USED 0
6708 #define SQLITE_DBSTATUS_CACHE_USED 1
6709 #define SQLITE_DBSTATUS_SCHEMA_USED 2
6710 #define SQLITE_DBSTATUS_STMT_USED 3
6711 #define SQLITE_DBSTATUS_LOOKASIDE_HIT 4
6712 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5
6713 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6
6714 #define SQLITE_DBSTATUS_CACHE_HIT 7
6715 #define SQLITE_DBSTATUS_CACHE_MISS 8
6716 #define SQLITE_DBSTATUS_CACHE_WRITE 9
6717 #define SQLITE_DBSTATUS_DEFERRED_FKS 10
6718 #define SQLITE_DBSTATUS_MAX 10 /* Largest defined DBSTATUS */
6722 ** CAPI3REF: Prepared Statement Status
6723 ** METHOD: sqlite3_stmt
6725 ** ^(Each prepared statement maintains various
6726 ** [SQLITE_STMTSTATUS counters] that measure the number
6727 ** of times it has performed specific operations.)^ These counters can
6728 ** be used to monitor the performance characteristics of the prepared
6729 ** statements. For example, if the number of table steps greatly exceeds
6730 ** the number of table searches or result rows, that would tend to indicate
6731 ** that the prepared statement is using a full table scan rather than
6734 ** ^(This interface is used to retrieve and reset counter values from
6735 ** a [prepared statement]. The first argument is the prepared statement
6736 ** object to be interrogated. The second argument
6737 ** is an integer code for a specific [SQLITE_STMTSTATUS counter]
6738 ** to be interrogated.)^
6739 ** ^The current value of the requested counter is returned.
6740 ** ^If the resetFlg is true, then the counter is reset to zero after this
6741 ** interface call returns.
6743 ** See also: [sqlite3_status()] and [sqlite3_db_status()].
6745 SQLITE_API int SQLITE_STDCALL sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
6748 ** CAPI3REF: Status Parameters for prepared statements
6749 ** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters}
6751 ** These preprocessor macros define integer codes that name counter
6752 ** values associated with the [sqlite3_stmt_status()] interface.
6753 ** The meanings of the various counters are as follows:
6756 ** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
6757 ** <dd>^This is the number of times that SQLite has stepped forward in
6758 ** a table as part of a full table scan. Large numbers for this counter
6759 ** may indicate opportunities for performance improvement through
6760 ** careful use of indices.</dd>
6762 ** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt>
6763 ** <dd>^This is the number of sort operations that have occurred.
6764 ** A non-zero value in this counter may indicate an opportunity to
6765 ** improvement performance through careful use of indices.</dd>
6767 ** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
6768 ** <dd>^This is the number of rows inserted into transient indices that
6769 ** were created automatically in order to help joins run faster.
6770 ** A non-zero value in this counter may indicate an opportunity to
6771 ** improvement performance by adding permanent indices that do not
6772 ** need to be reinitialized each time the statement is run.</dd>
6774 ** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt>
6775 ** <dd>^This is the number of virtual machine operations executed
6776 ** by the prepared statement if that number is less than or equal
6777 ** to 2147483647. The number of virtual machine operations can be
6778 ** used as a proxy for the total work done by the prepared statement.
6779 ** If the number of virtual machine operations exceeds 2147483647
6780 ** then the value returned by this statement status code is undefined.
6784 #define SQLITE_STMTSTATUS_FULLSCAN_STEP 1
6785 #define SQLITE_STMTSTATUS_SORT 2
6786 #define SQLITE_STMTSTATUS_AUTOINDEX 3
6787 #define SQLITE_STMTSTATUS_VM_STEP 4
6790 ** CAPI3REF: Custom Page Cache Object
6792 ** The sqlite3_pcache type is opaque. It is implemented by
6793 ** the pluggable module. The SQLite core has no knowledge of
6794 ** its size or internal structure and never deals with the
6795 ** sqlite3_pcache object except by holding and passing pointers
6798 ** See [sqlite3_pcache_methods2] for additional information.
6800 typedef struct sqlite3_pcache sqlite3_pcache;
6803 ** CAPI3REF: Custom Page Cache Object
6805 ** The sqlite3_pcache_page object represents a single page in the
6806 ** page cache. The page cache will allocate instances of this
6807 ** object. Various methods of the page cache use pointers to instances
6808 ** of this object as parameters or as their return value.
6810 ** See [sqlite3_pcache_methods2] for additional information.
6812 typedef struct sqlite3_pcache_page sqlite3_pcache_page;
6813 struct sqlite3_pcache_page {
6814 void *pBuf; /* The content of the page */
6815 void *pExtra; /* Extra information associated with the page */
6819 ** CAPI3REF: Application Defined Page Cache.
6820 ** KEYWORDS: {page cache}
6822 ** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can
6823 ** register an alternative page cache implementation by passing in an
6824 ** instance of the sqlite3_pcache_methods2 structure.)^
6825 ** In many applications, most of the heap memory allocated by
6826 ** SQLite is used for the page cache.
6827 ** By implementing a
6828 ** custom page cache using this API, an application can better control
6829 ** the amount of memory consumed by SQLite, the way in which
6830 ** that memory is allocated and released, and the policies used to
6831 ** determine exactly which parts of a database file are cached and for
6834 ** The alternative page cache mechanism is an
6835 ** extreme measure that is only needed by the most demanding applications.
6836 ** The built-in page cache is recommended for most uses.
6838 ** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an
6839 ** internal buffer by SQLite within the call to [sqlite3_config]. Hence
6840 ** the application may discard the parameter after the call to
6841 ** [sqlite3_config()] returns.)^
6843 ** [[the xInit() page cache method]]
6844 ** ^(The xInit() method is called once for each effective
6845 ** call to [sqlite3_initialize()])^
6846 ** (usually only once during the lifetime of the process). ^(The xInit()
6847 ** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^
6848 ** The intent of the xInit() method is to set up global data structures
6849 ** required by the custom page cache implementation.
6850 ** ^(If the xInit() method is NULL, then the
6851 ** built-in default page cache is used instead of the application defined
6854 ** [[the xShutdown() page cache method]]
6855 ** ^The xShutdown() method is called by [sqlite3_shutdown()].
6856 ** It can be used to clean up
6857 ** any outstanding resources before process shutdown, if required.
6858 ** ^The xShutdown() method may be NULL.
6860 ** ^SQLite automatically serializes calls to the xInit method,
6861 ** so the xInit method need not be threadsafe. ^The
6862 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
6863 ** not need to be threadsafe either. All other methods must be threadsafe
6864 ** in multithreaded applications.
6866 ** ^SQLite will never invoke xInit() more than once without an intervening
6867 ** call to xShutdown().
6869 ** [[the xCreate() page cache methods]]
6870 ** ^SQLite invokes the xCreate() method to construct a new cache instance.
6871 ** SQLite will typically create one cache instance for each open database file,
6872 ** though this is not guaranteed. ^The
6873 ** first parameter, szPage, is the size in bytes of the pages that must
6874 ** be allocated by the cache. ^szPage will always a power of two. ^The
6875 ** second parameter szExtra is a number of bytes of extra storage
6876 ** associated with each page cache entry. ^The szExtra parameter will
6877 ** a number less than 250. SQLite will use the
6878 ** extra szExtra bytes on each page to store metadata about the underlying
6879 ** database page on disk. The value passed into szExtra depends
6880 ** on the SQLite version, the target platform, and how SQLite was compiled.
6881 ** ^The third argument to xCreate(), bPurgeable, is true if the cache being
6882 ** created will be used to cache database pages of a file stored on disk, or
6883 ** false if it is used for an in-memory database. The cache implementation
6884 ** does not have to do anything special based with the value of bPurgeable;
6885 ** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will
6886 ** never invoke xUnpin() except to deliberately delete a page.
6887 ** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
6888 ** false will always have the "discard" flag set to true.
6889 ** ^Hence, a cache created with bPurgeable false will
6890 ** never contain any unpinned pages.
6892 ** [[the xCachesize() page cache method]]
6893 ** ^(The xCachesize() method may be called at any time by SQLite to set the
6894 ** suggested maximum cache-size (number of pages stored by) the cache
6895 ** instance passed as the first argument. This is the value configured using
6896 ** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable
6897 ** parameter, the implementation is not required to do anything with this
6898 ** value; it is advisory only.
6900 ** [[the xPagecount() page cache methods]]
6901 ** The xPagecount() method must return the number of pages currently
6902 ** stored in the cache, both pinned and unpinned.
6904 ** [[the xFetch() page cache methods]]
6905 ** The xFetch() method locates a page in the cache and returns a pointer to
6906 ** an sqlite3_pcache_page object associated with that page, or a NULL pointer.
6907 ** The pBuf element of the returned sqlite3_pcache_page object will be a
6908 ** pointer to a buffer of szPage bytes used to store the content of a
6909 ** single database page. The pExtra element of sqlite3_pcache_page will be
6910 ** a pointer to the szExtra bytes of extra storage that SQLite has requested
6911 ** for each entry in the page cache.
6913 ** The page to be fetched is determined by the key. ^The minimum key value
6914 ** is 1. After it has been retrieved using xFetch, the page is considered
6917 ** If the requested page is already in the page cache, then the page cache
6918 ** implementation must return a pointer to the page buffer with its content
6919 ** intact. If the requested page is not already in the cache, then the
6920 ** cache implementation should use the value of the createFlag
6921 ** parameter to help it determined what action to take:
6923 ** <table border=1 width=85% align=center>
6924 ** <tr><th> createFlag <th> Behavior when page is not already in cache
6925 ** <tr><td> 0 <td> Do not allocate a new page. Return NULL.
6926 ** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
6927 ** Otherwise return NULL.
6928 ** <tr><td> 2 <td> Make every effort to allocate a new page. Only return
6929 ** NULL if allocating a new page is effectively impossible.
6932 ** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite
6933 ** will only use a createFlag of 2 after a prior call with a createFlag of 1
6934 ** failed.)^ In between the to xFetch() calls, SQLite may
6935 ** attempt to unpin one or more cache pages by spilling the content of
6936 ** pinned pages to disk and synching the operating system disk cache.
6938 ** [[the xUnpin() page cache method]]
6939 ** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
6940 ** as its second argument. If the third parameter, discard, is non-zero,
6941 ** then the page must be evicted from the cache.
6942 ** ^If the discard parameter is
6943 ** zero, then the page may be discarded or retained at the discretion of
6944 ** page cache implementation. ^The page cache implementation
6945 ** may choose to evict unpinned pages at any time.
6947 ** The cache must not perform any reference counting. A single
6948 ** call to xUnpin() unpins the page regardless of the number of prior calls
6951 ** [[the xRekey() page cache methods]]
6952 ** The xRekey() method is used to change the key value associated with the
6953 ** page passed as the second argument. If the cache
6954 ** previously contains an entry associated with newKey, it must be
6955 ** discarded. ^Any prior cache entry associated with newKey is guaranteed not
6958 ** When SQLite calls the xTruncate() method, the cache must discard all
6959 ** existing cache entries with page numbers (keys) greater than or equal
6960 ** to the value of the iLimit parameter passed to xTruncate(). If any
6961 ** of these pages are pinned, they are implicitly unpinned, meaning that
6962 ** they can be safely discarded.
6964 ** [[the xDestroy() page cache method]]
6965 ** ^The xDestroy() method is used to delete a cache allocated by xCreate().
6966 ** All resources associated with the specified cache should be freed. ^After
6967 ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
6968 ** handle invalid, and will not use it with any other sqlite3_pcache_methods2
6971 ** [[the xShrink() page cache method]]
6972 ** ^SQLite invokes the xShrink() method when it wants the page cache to
6973 ** free up as much of heap memory as possible. The page cache implementation
6974 ** is not obligated to free any memory, but well-behaved implementations should
6977 typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
6978 struct sqlite3_pcache_methods2 {
6981 int (*xInit)(void*);
6982 void (*xShutdown)(void*);
6983 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
6984 void (*xCachesize)(sqlite3_pcache*, int nCachesize);
6985 int (*xPagecount)(sqlite3_pcache*);
6986 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
6987 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
6988 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*,
6989 unsigned oldKey, unsigned newKey);
6990 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
6991 void (*xDestroy)(sqlite3_pcache*);
6992 void (*xShrink)(sqlite3_pcache*);
6996 ** This is the obsolete pcache_methods object that has now been replaced
6997 ** by sqlite3_pcache_methods2. This object is not used by SQLite. It is
6998 ** retained in the header file for backwards compatibility only.
7000 typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
7001 struct sqlite3_pcache_methods {
7003 int (*xInit)(void*);
7004 void (*xShutdown)(void*);
7005 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
7006 void (*xCachesize)(sqlite3_pcache*, int nCachesize);
7007 int (*xPagecount)(sqlite3_pcache*);
7008 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
7009 void (*xUnpin)(sqlite3_pcache*, void*, int discard);
7010 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
7011 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
7012 void (*xDestroy)(sqlite3_pcache*);
7017 ** CAPI3REF: Online Backup Object
7019 ** The sqlite3_backup object records state information about an ongoing
7020 ** online backup operation. ^The sqlite3_backup object is created by
7021 ** a call to [sqlite3_backup_init()] and is destroyed by a call to
7022 ** [sqlite3_backup_finish()].
7024 ** See Also: [Using the SQLite Online Backup API]
7026 typedef struct sqlite3_backup sqlite3_backup;
7029 ** CAPI3REF: Online Backup API.
7031 ** The backup API copies the content of one database into another.
7032 ** It is useful either for creating backups of databases or
7033 ** for copying in-memory databases to or from persistent files.
7035 ** See Also: [Using the SQLite Online Backup API]
7037 ** ^SQLite holds a write transaction open on the destination database file
7038 ** for the duration of the backup operation.
7039 ** ^The source database is read-locked only while it is being read;
7040 ** it is not locked continuously for the entire backup operation.
7041 ** ^Thus, the backup may be performed on a live source database without
7042 ** preventing other database connections from
7043 ** reading or writing to the source database while the backup is underway.
7045 ** ^(To perform a backup operation:
7047 ** <li><b>sqlite3_backup_init()</b> is called once to initialize the
7049 ** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
7050 ** the data between the two databases, and finally
7051 ** <li><b>sqlite3_backup_finish()</b> is called to release all resources
7052 ** associated with the backup operation.
7054 ** There should be exactly one call to sqlite3_backup_finish() for each
7055 ** successful call to sqlite3_backup_init().
7057 ** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
7059 ** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
7060 ** [database connection] associated with the destination database
7061 ** and the database name, respectively.
7062 ** ^The database name is "main" for the main database, "temp" for the
7063 ** temporary database, or the name specified after the AS keyword in
7064 ** an [ATTACH] statement for an attached database.
7065 ** ^The S and M arguments passed to
7066 ** sqlite3_backup_init(D,N,S,M) identify the [database connection]
7067 ** and database name of the source database, respectively.
7068 ** ^The source and destination [database connections] (parameters S and D)
7069 ** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
7072 ** ^A call to sqlite3_backup_init() will fail, returning SQLITE_ERROR, if
7073 ** there is already a read or read-write transaction open on the
7074 ** destination database.
7076 ** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
7077 ** returned and an error code and error message are stored in the
7078 ** destination [database connection] D.
7079 ** ^The error code and message for the failed call to sqlite3_backup_init()
7080 ** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
7081 ** [sqlite3_errmsg16()] functions.
7082 ** ^A successful call to sqlite3_backup_init() returns a pointer to an
7083 ** [sqlite3_backup] object.
7084 ** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
7085 ** sqlite3_backup_finish() functions to perform the specified backup
7088 ** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
7090 ** ^Function sqlite3_backup_step(B,N) will copy up to N pages between
7091 ** the source and destination databases specified by [sqlite3_backup] object B.
7092 ** ^If N is negative, all remaining source pages are copied.
7093 ** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
7094 ** are still more pages to be copied, then the function returns [SQLITE_OK].
7095 ** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
7096 ** from source to destination, then it returns [SQLITE_DONE].
7097 ** ^If an error occurs while running sqlite3_backup_step(B,N),
7098 ** then an [error code] is returned. ^As well as [SQLITE_OK] and
7099 ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
7100 ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
7101 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
7103 ** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
7105 ** <li> the destination database was opened read-only, or
7106 ** <li> the destination database is using write-ahead-log journaling
7107 ** and the destination and source page sizes differ, or
7108 ** <li> the destination database is an in-memory database and the
7109 ** destination and source page sizes differ.
7112 ** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
7113 ** the [sqlite3_busy_handler | busy-handler function]
7114 ** is invoked (if one is specified). ^If the
7115 ** busy-handler returns non-zero before the lock is available, then
7116 ** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
7117 ** sqlite3_backup_step() can be retried later. ^If the source
7118 ** [database connection]
7119 ** is being used to write to the source database when sqlite3_backup_step()
7120 ** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
7121 ** case the call to sqlite3_backup_step() can be retried later on. ^(If
7122 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
7123 ** [SQLITE_READONLY] is returned, then
7124 ** there is no point in retrying the call to sqlite3_backup_step(). These
7125 ** errors are considered fatal.)^ The application must accept
7126 ** that the backup operation has failed and pass the backup operation handle
7127 ** to the sqlite3_backup_finish() to release associated resources.
7129 ** ^The first call to sqlite3_backup_step() obtains an exclusive lock
7130 ** on the destination file. ^The exclusive lock is not released until either
7131 ** sqlite3_backup_finish() is called or the backup operation is complete
7132 ** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to
7133 ** sqlite3_backup_step() obtains a [shared lock] on the source database that
7134 ** lasts for the duration of the sqlite3_backup_step() call.
7135 ** ^Because the source database is not locked between calls to
7136 ** sqlite3_backup_step(), the source database may be modified mid-way
7137 ** through the backup process. ^If the source database is modified by an
7138 ** external process or via a database connection other than the one being
7139 ** used by the backup operation, then the backup will be automatically
7140 ** restarted by the next call to sqlite3_backup_step(). ^If the source
7141 ** database is modified by the using the same database connection as is used
7142 ** by the backup operation, then the backup database is automatically
7143 ** updated at the same time.
7145 ** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
7147 ** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the
7148 ** application wishes to abandon the backup operation, the application
7149 ** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
7150 ** ^The sqlite3_backup_finish() interfaces releases all
7151 ** resources associated with the [sqlite3_backup] object.
7152 ** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
7153 ** active write-transaction on the destination database is rolled back.
7154 ** The [sqlite3_backup] object is invalid
7155 ** and may not be used following a call to sqlite3_backup_finish().
7157 ** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
7158 ** sqlite3_backup_step() errors occurred, regardless or whether or not
7159 ** sqlite3_backup_step() completed.
7160 ** ^If an out-of-memory condition or IO error occurred during any prior
7161 ** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
7162 ** sqlite3_backup_finish() returns the corresponding [error code].
7164 ** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
7165 ** is not a permanent error and does not affect the return value of
7166 ** sqlite3_backup_finish().
7168 ** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]]
7169 ** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
7171 ** ^The sqlite3_backup_remaining() routine returns the number of pages still
7172 ** to be backed up at the conclusion of the most recent sqlite3_backup_step().
7173 ** ^The sqlite3_backup_pagecount() routine returns the total number of pages
7174 ** in the source database at the conclusion of the most recent
7175 ** sqlite3_backup_step().
7176 ** ^(The values returned by these functions are only updated by
7177 ** sqlite3_backup_step(). If the source database is modified in a way that
7178 ** changes the size of the source database or the number of pages remaining,
7179 ** those changes are not reflected in the output of sqlite3_backup_pagecount()
7180 ** and sqlite3_backup_remaining() until after the next
7181 ** sqlite3_backup_step().)^
7183 ** <b>Concurrent Usage of Database Handles</b>
7185 ** ^The source [database connection] may be used by the application for other
7186 ** purposes while a backup operation is underway or being initialized.
7187 ** ^If SQLite is compiled and configured to support threadsafe database
7188 ** connections, then the source database connection may be used concurrently
7189 ** from within other threads.
7191 ** However, the application must guarantee that the destination
7192 ** [database connection] is not passed to any other API (by any thread) after
7193 ** sqlite3_backup_init() is called and before the corresponding call to
7194 ** sqlite3_backup_finish(). SQLite does not currently check to see
7195 ** if the application incorrectly accesses the destination [database connection]
7196 ** and so no error code is reported, but the operations may malfunction
7197 ** nevertheless. Use of the destination database connection while a
7198 ** backup is in progress might also also cause a mutex deadlock.
7200 ** If running in [shared cache mode], the application must
7201 ** guarantee that the shared cache used by the destination database
7202 ** is not accessed while the backup is running. In practice this means
7203 ** that the application must guarantee that the disk file being
7204 ** backed up to is not accessed by any connection within the process,
7205 ** not just the specific connection that was passed to sqlite3_backup_init().
7207 ** The [sqlite3_backup] object itself is partially threadsafe. Multiple
7208 ** threads may safely make multiple concurrent calls to sqlite3_backup_step().
7209 ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
7210 ** APIs are not strictly speaking threadsafe. If they are invoked at the
7211 ** same time as another thread is invoking sqlite3_backup_step() it is
7212 ** possible that they return invalid values.
7214 SQLITE_API sqlite3_backup *SQLITE_STDCALL sqlite3_backup_init(
7215 sqlite3 *pDest, /* Destination database handle */
7216 const char *zDestName, /* Destination database name */
7217 sqlite3 *pSource, /* Source database handle */
7218 const char *zSourceName /* Source database name */
7220 SQLITE_API int SQLITE_STDCALL sqlite3_backup_step(sqlite3_backup *p, int nPage);
7221 SQLITE_API int SQLITE_STDCALL sqlite3_backup_finish(sqlite3_backup *p);
7222 SQLITE_API int SQLITE_STDCALL sqlite3_backup_remaining(sqlite3_backup *p);
7223 SQLITE_API int SQLITE_STDCALL sqlite3_backup_pagecount(sqlite3_backup *p);
7226 ** CAPI3REF: Unlock Notification
7229 ** ^When running in shared-cache mode, a database operation may fail with
7230 ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
7231 ** individual tables within the shared-cache cannot be obtained. See
7232 ** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
7233 ** ^This API may be used to register a callback that SQLite will invoke
7234 ** when the connection currently holding the required lock relinquishes it.
7235 ** ^This API is only available if the library was compiled with the
7236 ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
7238 ** See Also: [Using the SQLite Unlock Notification Feature].
7240 ** ^Shared-cache locks are released when a database connection concludes
7241 ** its current transaction, either by committing it or rolling it back.
7243 ** ^When a connection (known as the blocked connection) fails to obtain a
7244 ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
7245 ** identity of the database connection (the blocking connection) that
7246 ** has locked the required resource is stored internally. ^After an
7247 ** application receives an SQLITE_LOCKED error, it may call the
7248 ** sqlite3_unlock_notify() method with the blocked connection handle as
7249 ** the first argument to register for a callback that will be invoked
7250 ** when the blocking connections current transaction is concluded. ^The
7251 ** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
7252 ** call that concludes the blocking connections transaction.
7254 ** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
7255 ** there is a chance that the blocking connection will have already
7256 ** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
7257 ** If this happens, then the specified callback is invoked immediately,
7258 ** from within the call to sqlite3_unlock_notify().)^
7260 ** ^If the blocked connection is attempting to obtain a write-lock on a
7261 ** shared-cache table, and more than one other connection currently holds
7262 ** a read-lock on the same table, then SQLite arbitrarily selects one of
7263 ** the other connections to use as the blocking connection.
7265 ** ^(There may be at most one unlock-notify callback registered by a
7266 ** blocked connection. If sqlite3_unlock_notify() is called when the
7267 ** blocked connection already has a registered unlock-notify callback,
7268 ** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
7269 ** called with a NULL pointer as its second argument, then any existing
7270 ** unlock-notify callback is canceled. ^The blocked connections
7271 ** unlock-notify callback may also be canceled by closing the blocked
7272 ** connection using [sqlite3_close()].
7274 ** The unlock-notify callback is not reentrant. If an application invokes
7275 ** any sqlite3_xxx API functions from within an unlock-notify callback, a
7276 ** crash or deadlock may be the result.
7278 ** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
7279 ** returns SQLITE_OK.
7281 ** <b>Callback Invocation Details</b>
7283 ** When an unlock-notify callback is registered, the application provides a
7284 ** single void* pointer that is passed to the callback when it is invoked.
7285 ** However, the signature of the callback function allows SQLite to pass
7286 ** it an array of void* context pointers. The first argument passed to
7287 ** an unlock-notify callback is a pointer to an array of void* pointers,
7288 ** and the second is the number of entries in the array.
7290 ** When a blocking connections transaction is concluded, there may be
7291 ** more than one blocked connection that has registered for an unlock-notify
7292 ** callback. ^If two or more such blocked connections have specified the
7293 ** same callback function, then instead of invoking the callback function
7294 ** multiple times, it is invoked once with the set of void* context pointers
7295 ** specified by the blocked connections bundled together into an array.
7296 ** This gives the application an opportunity to prioritize any actions
7297 ** related to the set of unblocked database connections.
7299 ** <b>Deadlock Detection</b>
7301 ** Assuming that after registering for an unlock-notify callback a
7302 ** database waits for the callback to be issued before taking any further
7303 ** action (a reasonable assumption), then using this API may cause the
7304 ** application to deadlock. For example, if connection X is waiting for
7305 ** connection Y's transaction to be concluded, and similarly connection
7306 ** Y is waiting on connection X's transaction, then neither connection
7307 ** will proceed and the system may remain deadlocked indefinitely.
7309 ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
7310 ** detection. ^If a given call to sqlite3_unlock_notify() would put the
7311 ** system in a deadlocked state, then SQLITE_LOCKED is returned and no
7312 ** unlock-notify callback is registered. The system is said to be in
7313 ** a deadlocked state if connection A has registered for an unlock-notify
7314 ** callback on the conclusion of connection B's transaction, and connection
7315 ** B has itself registered for an unlock-notify callback when connection
7316 ** A's transaction is concluded. ^Indirect deadlock is also detected, so
7317 ** the system is also considered to be deadlocked if connection B has
7318 ** registered for an unlock-notify callback on the conclusion of connection
7319 ** C's transaction, where connection C is waiting on connection A. ^Any
7320 ** number of levels of indirection are allowed.
7322 ** <b>The "DROP TABLE" Exception</b>
7324 ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost
7325 ** always appropriate to call sqlite3_unlock_notify(). There is however,
7326 ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
7327 ** SQLite checks if there are any currently executing SELECT statements
7328 ** that belong to the same connection. If there are, SQLITE_LOCKED is
7329 ** returned. In this case there is no "blocking connection", so invoking
7330 ** sqlite3_unlock_notify() results in the unlock-notify callback being
7331 ** invoked immediately. If the application then re-attempts the "DROP TABLE"
7332 ** or "DROP INDEX" query, an infinite loop might be the result.
7334 ** One way around this problem is to check the extended error code returned
7335 ** by an sqlite3_step() call. ^(If there is a blocking connection, then the
7336 ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
7337 ** the special "DROP TABLE/INDEX" case, the extended error code is just
7340 SQLITE_API int SQLITE_STDCALL sqlite3_unlock_notify(
7341 sqlite3 *pBlocked, /* Waiting connection */
7342 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */
7343 void *pNotifyArg /* Argument to pass to xNotify */
7348 ** CAPI3REF: String Comparison
7350 ** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications
7351 ** and extensions to compare the contents of two buffers containing UTF-8
7352 ** strings in a case-independent fashion, using the same definition of "case
7353 ** independence" that SQLite uses internally when comparing identifiers.
7355 SQLITE_API int SQLITE_STDCALL sqlite3_stricmp(const char *, const char *);
7356 SQLITE_API int SQLITE_STDCALL sqlite3_strnicmp(const char *, const char *, int);
7359 ** CAPI3REF: String Globbing
7361 ** ^The [sqlite3_strglob(P,X)] interface returns zero if string X matches
7362 ** the glob pattern P, and it returns non-zero if string X does not match
7363 ** the glob pattern P. ^The definition of glob pattern matching used in
7364 ** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the
7365 ** SQL dialect used by SQLite. ^The sqlite3_strglob(P,X) function is case
7368 ** Note that this routine returns zero on a match and non-zero if the strings
7369 ** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
7371 SQLITE_API int SQLITE_STDCALL sqlite3_strglob(const char *zGlob, const char *zStr);
7374 ** CAPI3REF: Error Logging Interface
7376 ** ^The [sqlite3_log()] interface writes a message into the [error log]
7377 ** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
7378 ** ^If logging is enabled, the zFormat string and subsequent arguments are
7379 ** used with [sqlite3_snprintf()] to generate the final output string.
7381 ** The sqlite3_log() interface is intended for use by extensions such as
7382 ** virtual tables, collating functions, and SQL functions. While there is
7383 ** nothing to prevent an application from calling sqlite3_log(), doing so
7384 ** is considered bad form.
7386 ** The zFormat string must not be NULL.
7388 ** To avoid deadlocks and other threading problems, the sqlite3_log() routine
7389 ** will not use dynamically allocated memory. The log message is stored in
7390 ** a fixed-length buffer on the stack. If the log message is longer than
7391 ** a few hundred characters, it will be truncated to the length of the
7394 SQLITE_API void SQLITE_CDECL sqlite3_log(int iErrCode, const char *zFormat, ...);
7397 ** CAPI3REF: Write-Ahead Log Commit Hook
7400 ** ^The [sqlite3_wal_hook()] function is used to register a callback that
7401 ** is invoked each time data is committed to a database in wal mode.
7403 ** ^(The callback is invoked by SQLite after the commit has taken place and
7404 ** the associated write-lock on the database released)^, so the implementation
7405 ** may read, write or [checkpoint] the database as required.
7407 ** ^The first parameter passed to the callback function when it is invoked
7408 ** is a copy of the third parameter passed to sqlite3_wal_hook() when
7409 ** registering the callback. ^The second is a copy of the database handle.
7410 ** ^The third parameter is the name of the database that was written to -
7411 ** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
7412 ** is the number of pages currently in the write-ahead log file,
7413 ** including those that were just committed.
7415 ** The callback function should normally return [SQLITE_OK]. ^If an error
7416 ** code is returned, that error will propagate back up through the
7417 ** SQLite code base to cause the statement that provoked the callback
7418 ** to report an error, though the commit will have still occurred. If the
7419 ** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
7420 ** that does not correspond to any valid SQLite error code, the results
7423 ** A single database handle may have at most a single write-ahead log callback
7424 ** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
7425 ** previously registered write-ahead log callback. ^Note that the
7426 ** [sqlite3_wal_autocheckpoint()] interface and the
7427 ** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
7428 ** those overwrite any prior [sqlite3_wal_hook()] settings.
7430 SQLITE_API void *SQLITE_STDCALL sqlite3_wal_hook(
7432 int(*)(void *,sqlite3*,const char*,int),
7437 ** CAPI3REF: Configure an auto-checkpoint
7440 ** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
7441 ** [sqlite3_wal_hook()] that causes any database on [database connection] D
7442 ** to automatically [checkpoint]
7443 ** after committing a transaction if there are N or
7444 ** more frames in the [write-ahead log] file. ^Passing zero or
7445 ** a negative value as the nFrame parameter disables automatic
7446 ** checkpoints entirely.
7448 ** ^The callback registered by this function replaces any existing callback
7449 ** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback
7450 ** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
7451 ** configured by this function.
7453 ** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
7456 ** ^Checkpoints initiated by this mechanism are
7457 ** [sqlite3_wal_checkpoint_v2|PASSIVE].
7459 ** ^Every new [database connection] defaults to having the auto-checkpoint
7460 ** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
7461 ** pages. The use of this interface
7462 ** is only necessary if the default setting is found to be suboptimal
7463 ** for a particular application.
7465 SQLITE_API int SQLITE_STDCALL sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
7468 ** CAPI3REF: Checkpoint a database
7471 ** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to
7472 ** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^
7474 ** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the
7475 ** [write-ahead log] for database X on [database connection] D to be
7476 ** transferred into the database file and for the write-ahead log to
7477 ** be reset. See the [checkpointing] documentation for addition
7480 ** This interface used to be the only way to cause a checkpoint to
7481 ** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()]
7482 ** interface was added. This interface is retained for backwards
7483 ** compatibility and as a convenience for applications that need to manually
7484 ** start a callback but which do not need the full power (and corresponding
7485 ** complication) of [sqlite3_wal_checkpoint_v2()].
7487 SQLITE_API int SQLITE_STDCALL sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
7490 ** CAPI3REF: Checkpoint a database
7493 ** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint
7494 ** operation on database X of [database connection] D in mode M. Status
7495 ** information is written back into integers pointed to by L and C.)^
7496 ** ^(The M parameter must be a valid [checkpoint mode]:)^
7499 ** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
7500 ** ^Checkpoint as many frames as possible without waiting for any database
7501 ** readers or writers to finish, then sync the database file if all frames
7502 ** in the log were checkpointed. ^The [busy-handler callback]
7503 ** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode.
7504 ** ^On the other hand, passive mode might leave the checkpoint unfinished
7505 ** if there are concurrent readers or writers.
7507 ** <dt>SQLITE_CHECKPOINT_FULL<dd>
7508 ** ^This mode blocks (it invokes the
7509 ** [sqlite3_busy_handler|busy-handler callback]) until there is no
7510 ** database writer and all readers are reading from the most recent database
7511 ** snapshot. ^It then checkpoints all frames in the log file and syncs the
7512 ** database file. ^This mode blocks new database writers while it is pending,
7513 ** but new database readers are allowed to continue unimpeded.
7515 ** <dt>SQLITE_CHECKPOINT_RESTART<dd>
7516 ** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition
7517 ** that after checkpointing the log file it blocks (calls the
7518 ** [busy-handler callback])
7519 ** until all readers are reading from the database file only. ^This ensures
7520 ** that the next writer will restart the log file from the beginning.
7521 ** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new
7522 ** database writer attempts while it is pending, but does not impede readers.
7524 ** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd>
7525 ** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the
7526 ** addition that it also truncates the log file to zero bytes just prior
7527 ** to a successful return.
7530 ** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in
7531 ** the log file or to -1 if the checkpoint could not run because
7532 ** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not
7533 ** NULL,then *pnCkpt is set to the total number of checkpointed frames in the
7534 ** log file (including any that were already checkpointed before the function
7535 ** was called) or to -1 if the checkpoint could not run due to an error or
7536 ** because the database is not in WAL mode. ^Note that upon successful
7537 ** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been
7538 ** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero.
7540 ** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If
7541 ** any other process is running a checkpoint operation at the same time, the
7542 ** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a
7543 ** busy-handler configured, it will not be invoked in this case.
7545 ** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the
7546 ** exclusive "writer" lock on the database file. ^If the writer lock cannot be
7547 ** obtained immediately, and a busy-handler is configured, it is invoked and
7548 ** the writer lock retried until either the busy-handler returns 0 or the lock
7549 ** is successfully obtained. ^The busy-handler is also invoked while waiting for
7550 ** database readers as described above. ^If the busy-handler returns 0 before
7551 ** the writer lock is obtained or while waiting for database readers, the
7552 ** checkpoint operation proceeds from that point in the same way as
7553 ** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible
7554 ** without blocking any further. ^SQLITE_BUSY is returned in this case.
7556 ** ^If parameter zDb is NULL or points to a zero length string, then the
7557 ** specified operation is attempted on all WAL databases [attached] to
7558 ** [database connection] db. In this case the
7559 ** values written to output parameters *pnLog and *pnCkpt are undefined. ^If
7560 ** an SQLITE_BUSY error is encountered when processing one or more of the
7561 ** attached WAL databases, the operation is still attempted on any remaining
7562 ** attached databases and SQLITE_BUSY is returned at the end. ^If any other
7563 ** error occurs while processing an attached database, processing is abandoned
7564 ** and the error code is returned to the caller immediately. ^If no error
7565 ** (SQLITE_BUSY or otherwise) is encountered while processing the attached
7566 ** databases, SQLITE_OK is returned.
7568 ** ^If database zDb is the name of an attached database that is not in WAL
7569 ** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If
7570 ** zDb is not NULL (or a zero length string) and is not the name of any
7571 ** attached database, SQLITE_ERROR is returned to the caller.
7573 ** ^Unless it returns SQLITE_MISUSE,
7574 ** the sqlite3_wal_checkpoint_v2() interface
7575 ** sets the error information that is queried by
7576 ** [sqlite3_errcode()] and [sqlite3_errmsg()].
7578 ** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface
7581 SQLITE_API int SQLITE_STDCALL sqlite3_wal_checkpoint_v2(
7582 sqlite3 *db, /* Database handle */
7583 const char *zDb, /* Name of attached database (or NULL) */
7584 int eMode, /* SQLITE_CHECKPOINT_* value */
7585 int *pnLog, /* OUT: Size of WAL log in frames */
7586 int *pnCkpt /* OUT: Total number of frames checkpointed */
7590 ** CAPI3REF: Checkpoint Mode Values
7591 ** KEYWORDS: {checkpoint mode}
7593 ** These constants define all valid values for the "checkpoint mode" passed
7594 ** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface.
7595 ** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the
7596 ** meaning of each of these checkpoint modes.
7598 #define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */
7599 #define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */
7600 #define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */
7601 #define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */
7604 ** CAPI3REF: Virtual Table Interface Configuration
7606 ** This function may be called by either the [xConnect] or [xCreate] method
7607 ** of a [virtual table] implementation to configure
7608 ** various facets of the virtual table interface.
7610 ** If this interface is invoked outside the context of an xConnect or
7611 ** xCreate virtual table method then the behavior is undefined.
7613 ** At present, there is only one option that may be configured using
7614 ** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options
7615 ** may be added in the future.
7617 SQLITE_API int SQLITE_CDECL sqlite3_vtab_config(sqlite3*, int op, ...);
7620 ** CAPI3REF: Virtual Table Configuration Options
7622 ** These macros define the various options to the
7623 ** [sqlite3_vtab_config()] interface that [virtual table] implementations
7624 ** can use to customize and optimize their behavior.
7627 ** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT
7628 ** <dd>Calls of the form
7629 ** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
7630 ** where X is an integer. If X is zero, then the [virtual table] whose
7631 ** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not
7632 ** support constraints. In this configuration (which is the default) if
7633 ** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire
7634 ** statement is rolled back as if [ON CONFLICT | OR ABORT] had been
7635 ** specified as part of the users SQL statement, regardless of the actual
7636 ** ON CONFLICT mode specified.
7638 ** If X is non-zero, then the virtual table implementation guarantees
7639 ** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before
7640 ** any modifications to internal or persistent data structures have been made.
7641 ** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite
7642 ** is able to roll back a statement or database transaction, and abandon
7643 ** or continue processing the current SQL statement as appropriate.
7644 ** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns
7645 ** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode
7648 ** Virtual table implementations that are required to handle OR REPLACE
7649 ** must do so within the [xUpdate] method. If a call to the
7650 ** [sqlite3_vtab_on_conflict()] function indicates that the current ON
7651 ** CONFLICT policy is REPLACE, the virtual table implementation should
7652 ** silently replace the appropriate rows within the xUpdate callback and
7653 ** return SQLITE_OK. Or, if this is not possible, it may return
7654 ** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT
7655 ** constraint handling.
7658 #define SQLITE_VTAB_CONSTRAINT_SUPPORT 1
7661 ** CAPI3REF: Determine The Virtual Table Conflict Policy
7663 ** This function may only be called from within a call to the [xUpdate] method
7664 ** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The
7665 ** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
7666 ** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
7667 ** of the SQL statement that triggered the call to the [xUpdate] method of the
7670 SQLITE_API int SQLITE_STDCALL sqlite3_vtab_on_conflict(sqlite3 *);
7673 ** CAPI3REF: Conflict resolution modes
7674 ** KEYWORDS: {conflict resolution mode}
7676 ** These constants are returned by [sqlite3_vtab_on_conflict()] to
7677 ** inform a [virtual table] implementation what the [ON CONFLICT] mode
7678 ** is for the SQL statement being evaluated.
7680 ** Note that the [SQLITE_IGNORE] constant is also used as a potential
7681 ** return value from the [sqlite3_set_authorizer()] callback and that
7682 ** [SQLITE_ABORT] is also a [result code].
7684 #define SQLITE_ROLLBACK 1
7685 /* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
7686 #define SQLITE_FAIL 3
7687 /* #define SQLITE_ABORT 4 // Also an error code */
7688 #define SQLITE_REPLACE 5
7691 ** CAPI3REF: Prepared Statement Scan Status Opcodes
7692 ** KEYWORDS: {scanstatus options}
7694 ** The following constants can be used for the T parameter to the
7695 ** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a
7696 ** different metric for sqlite3_stmt_scanstatus() to return.
7698 ** When the value returned to V is a string, space to hold that string is
7699 ** managed by the prepared statement S and will be automatically freed when
7703 ** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt>
7704 ** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be
7705 ** set to the total number of times that the X-th loop has run.</dd>
7707 ** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt>
7708 ** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set
7709 ** to the total number of rows examined by all iterations of the X-th loop.</dd>
7711 ** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt>
7712 ** <dd>^The "double" variable pointed to by the T parameter will be set to the
7713 ** query planner's estimate for the average number of rows output from each
7714 ** iteration of the X-th loop. If the query planner's estimates was accurate,
7715 ** then this value will approximate the quotient NVISIT/NLOOP and the
7716 ** product of this value for all prior loops with the same SELECTID will
7717 ** be the NLOOP value for the current loop.
7719 ** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt>
7720 ** <dd>^The "const char *" variable pointed to by the T parameter will be set
7721 ** to a zero-terminated UTF-8 string containing the name of the index or table
7722 ** used for the X-th loop.
7724 ** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt>
7725 ** <dd>^The "const char *" variable pointed to by the T parameter will be set
7726 ** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN]
7727 ** description for the X-th loop.
7729 ** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt>
7730 ** <dd>^The "int" variable pointed to by the T parameter will be set to the
7731 ** "select-id" for the X-th loop. The select-id identifies which query or
7732 ** subquery the loop is part of. The main query has a select-id of zero.
7733 ** The select-id is the same value as is output in the first column
7734 ** of an [EXPLAIN QUERY PLAN] query.
7737 #define SQLITE_SCANSTAT_NLOOP 0
7738 #define SQLITE_SCANSTAT_NVISIT 1
7739 #define SQLITE_SCANSTAT_EST 2
7740 #define SQLITE_SCANSTAT_NAME 3
7741 #define SQLITE_SCANSTAT_EXPLAIN 4
7742 #define SQLITE_SCANSTAT_SELECTID 5
7745 ** CAPI3REF: Prepared Statement Scan Status
7746 ** METHOD: sqlite3_stmt
7748 ** This interface returns information about the predicted and measured
7749 ** performance for pStmt. Advanced applications can use this
7750 ** interface to compare the predicted and the measured performance and
7751 ** issue warnings and/or rerun [ANALYZE] if discrepancies are found.
7753 ** Since this interface is expected to be rarely used, it is only
7754 ** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS]
7755 ** compile-time option.
7757 ** The "iScanStatusOp" parameter determines which status information to return.
7758 ** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior
7759 ** of this interface is undefined.
7760 ** ^The requested measurement is written into a variable pointed to by
7761 ** the "pOut" parameter.
7762 ** Parameter "idx" identifies the specific loop to retrieve statistics for.
7763 ** Loops are numbered starting from zero. ^If idx is out of range - less than
7764 ** zero or greater than or equal to the total number of loops used to implement
7765 ** the statement - a non-zero value is returned and the variable that pOut
7766 ** points to is unchanged.
7768 ** ^Statistics might not be available for all loops in all statements. ^In cases
7769 ** where there exist loops with no available statistics, this function behaves
7770 ** as if the loop did not exist - it returns non-zero and leave the variable
7771 ** that pOut points to unchanged.
7773 ** See also: [sqlite3_stmt_scanstatus_reset()]
7775 SQLITE_API int SQLITE_STDCALL sqlite3_stmt_scanstatus(
7776 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */
7777 int idx, /* Index of loop to report on */
7778 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */
7779 void *pOut /* Result written here */
7783 ** CAPI3REF: Zero Scan-Status Counters
7784 ** METHOD: sqlite3_stmt
7786 ** ^Zero all [sqlite3_stmt_scanstatus()] related event counters.
7788 ** This API is only available if the library is built with pre-processor
7789 ** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined.
7791 SQLITE_API void SQLITE_STDCALL sqlite3_stmt_scanstatus_reset(sqlite3_stmt*);
7795 ** Undo the hack that converts floating point types to integer for
7796 ** builds on processors without floating point support.
7798 #ifdef SQLITE_OMIT_FLOATING_POINT
7803 } /* End of the 'extern "C"' block */
7805 #endif /* _SQLITE3_H_ */
7810 ** The author disclaims copyright to this source code. In place of
7811 ** a legal notice, here is a blessing:
7813 ** May you do good and not evil.
7814 ** May you find forgiveness for yourself and forgive others.
7815 ** May you share freely, never taking more than you give.
7817 *************************************************************************
7820 #ifndef _SQLITE3RTREE_H_
7821 #define _SQLITE3RTREE_H_
7828 typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry;
7829 typedef struct sqlite3_rtree_query_info sqlite3_rtree_query_info;
7831 /* The double-precision datatype used by RTree depends on the
7832 ** SQLITE_RTREE_INT_ONLY compile-time option.
7834 #ifdef SQLITE_RTREE_INT_ONLY
7835 typedef sqlite3_int64 sqlite3_rtree_dbl;
7837 typedef double sqlite3_rtree_dbl;
7841 ** Register a geometry callback named zGeom that can be used as part of an
7842 ** R-Tree geometry query as follows:
7844 ** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...)
7846 SQLITE_API int SQLITE_STDCALL sqlite3_rtree_geometry_callback(
7849 int (*xGeom)(sqlite3_rtree_geometry*, int, sqlite3_rtree_dbl*,int*),
7855 ** A pointer to a structure of the following type is passed as the first
7856 ** argument to callbacks registered using rtree_geometry_callback().
7858 struct sqlite3_rtree_geometry {
7859 void *pContext; /* Copy of pContext passed to s_r_g_c() */
7860 int nParam; /* Size of array aParam[] */
7861 sqlite3_rtree_dbl *aParam; /* Parameters passed to SQL geom function */
7862 void *pUser; /* Callback implementation user data */
7863 void (*xDelUser)(void *); /* Called by SQLite to clean up pUser */
7867 ** Register a 2nd-generation geometry callback named zScore that can be
7868 ** used as part of an R-Tree geometry query as follows:
7870 ** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zQueryFunc(... params ...)
7872 SQLITE_API int SQLITE_STDCALL sqlite3_rtree_query_callback(
7874 const char *zQueryFunc,
7875 int (*xQueryFunc)(sqlite3_rtree_query_info*),
7877 void (*xDestructor)(void*)
7882 ** A pointer to a structure of the following type is passed as the
7883 ** argument to scored geometry callback registered using
7884 ** sqlite3_rtree_query_callback().
7886 ** Note that the first 5 fields of this structure are identical to
7887 ** sqlite3_rtree_geometry. This structure is a subclass of
7888 ** sqlite3_rtree_geometry.
7890 struct sqlite3_rtree_query_info {
7891 void *pContext; /* pContext from when function registered */
7892 int nParam; /* Number of function parameters */
7893 sqlite3_rtree_dbl *aParam; /* value of function parameters */
7894 void *pUser; /* callback can use this, if desired */
7895 void (*xDelUser)(void*); /* function to free pUser */
7896 sqlite3_rtree_dbl *aCoord; /* Coordinates of node or entry to check */
7897 unsigned int *anQueue; /* Number of pending entries in the queue */
7898 int nCoord; /* Number of coordinates */
7899 int iLevel; /* Level of current node or entry */
7900 int mxLevel; /* The largest iLevel value in the tree */
7901 sqlite3_int64 iRowid; /* Rowid for current entry */
7902 sqlite3_rtree_dbl rParentScore; /* Score of parent node */
7903 int eParentWithin; /* Visibility of parent node */
7904 int eWithin; /* OUT: Visiblity */
7905 sqlite3_rtree_dbl rScore; /* OUT: Write the score here */
7906 /* The following fields are only available in 3.8.11 and later */
7907 sqlite3_value **apSqlParam; /* Original SQL values of parameters */
7911 ** Allowed values for sqlite3_rtree_query.eWithin and .eParentWithin.
7913 #define NOT_WITHIN 0 /* Object completely outside of query region */
7914 #define PARTLY_WITHIN 1 /* Object partially overlaps query region */
7915 #define FULLY_WITHIN 2 /* Object fully contained within query region */
7919 } /* end of the 'extern "C"' block */
7922 #endif /* ifndef _SQLITE3RTREE_H_ */
7927 ** The author disclaims copyright to this source code. In place of
7928 ** a legal notice, here is a blessing:
7930 ** May you do good and not evil.
7931 ** May you find forgiveness for yourself and forgive others.
7932 ** May you share freely, never taking more than you give.
7934 ******************************************************************************
7936 ** Interfaces to extend FTS5. Using the interfaces defined in this file,
7937 ** FTS5 may be extended with:
7939 ** * custom tokenizers, and
7940 ** * custom auxiliary functions.
7947 #include "sqlite3.h"
7953 /*************************************************************************
7954 ** CUSTOM AUXILIARY FUNCTIONS
7956 ** Virtual table implementations may overload SQL functions by implementing
7957 ** the sqlite3_module.xFindFunction() method.
7960 typedef struct Fts5ExtensionApi Fts5ExtensionApi;
7961 typedef struct Fts5Context Fts5Context;
7962 typedef struct Fts5PhraseIter Fts5PhraseIter;
7964 typedef void (*fts5_extension_function)(
7965 const Fts5ExtensionApi *pApi, /* API offered by current FTS version */
7966 Fts5Context *pFts, /* First arg to pass to pApi functions */
7967 sqlite3_context *pCtx, /* Context for returning result/error */
7968 int nVal, /* Number of values in apVal[] array */
7969 sqlite3_value **apVal /* Array of trailing arguments */
7972 struct Fts5PhraseIter {
7973 const unsigned char *a;
7974 const unsigned char *b;
7978 ** EXTENSION API FUNCTIONS
7981 ** Return a copy of the context pointer the extension function was
7984 ** xColumnTotalSize(pFts, iCol, pnToken):
7985 ** If parameter iCol is less than zero, set output variable *pnToken
7986 ** to the total number of tokens in the FTS5 table. Or, if iCol is
7987 ** non-negative but less than the number of columns in the table, return
7988 ** the total number of tokens in column iCol, considering all rows in
7991 ** If parameter iCol is greater than or equal to the number of columns
7992 ** in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g.
7993 ** an OOM condition or IO error), an appropriate SQLite error code is
7996 ** xColumnCount(pFts):
7997 ** Return the number of columns in the table.
7999 ** xColumnSize(pFts, iCol, pnToken):
8000 ** If parameter iCol is less than zero, set output variable *pnToken
8001 ** to the total number of tokens in the current row. Or, if iCol is
8002 ** non-negative but less than the number of columns in the table, set
8003 ** *pnToken to the number of tokens in column iCol of the current row.
8005 ** If parameter iCol is greater than or equal to the number of columns
8006 ** in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g.
8007 ** an OOM condition or IO error), an appropriate SQLite error code is
8011 ** This function attempts to retrieve the text of column iCol of the
8012 ** current document. If successful, (*pz) is set to point to a buffer
8013 ** containing the text in utf-8 encoding, (*pn) is set to the size in bytes
8014 ** (not characters) of the buffer and SQLITE_OK is returned. Otherwise,
8015 ** if an error occurs, an SQLite error code is returned and the final values
8016 ** of (*pz) and (*pn) are undefined.
8019 ** Returns the number of phrases in the current query expression.
8022 ** Returns the number of tokens in phrase iPhrase of the query. Phrases
8023 ** are numbered starting from zero.
8026 ** Set *pnInst to the total number of occurrences of all phrases within
8027 ** the query within the current row. Return SQLITE_OK if successful, or
8028 ** an error code (i.e. SQLITE_NOMEM) if an error occurs.
8031 ** Query for the details of phrase match iIdx within the current row.
8032 ** Phrase matches are numbered starting from zero, so the iIdx argument
8033 ** should be greater than or equal to zero and smaller than the value
8034 ** output by xInstCount().
8036 ** Returns SQLITE_OK if successful, or an error code (i.e. SQLITE_NOMEM)
8037 ** if an error occurs.
8040 ** Returns the rowid of the current row.
8043 ** Tokenize text using the tokenizer belonging to the FTS5 table.
8045 ** xQueryPhrase(pFts5, iPhrase, pUserData, xCallback):
8046 ** This API function is used to query the FTS table for phrase iPhrase
8047 ** of the current query. Specifically, a query equivalent to:
8049 ** ... FROM ftstable WHERE ftstable MATCH $p ORDER BY rowid
8051 ** with $p set to a phrase equivalent to the phrase iPhrase of the
8052 ** current query is executed. For each row visited, the callback function
8053 ** passed as the fourth argument is invoked. The context and API objects
8054 ** passed to the callback function may be used to access the properties of
8055 ** each matched row. Invoking Api.xUserData() returns a copy of the pointer
8056 ** passed as the third argument to pUserData.
8058 ** If the callback function returns any value other than SQLITE_OK, the
8059 ** query is abandoned and the xQueryPhrase function returns immediately.
8060 ** If the returned value is SQLITE_DONE, xQueryPhrase returns SQLITE_OK.
8061 ** Otherwise, the error code is propagated upwards.
8063 ** If the query runs to completion without incident, SQLITE_OK is returned.
8064 ** Or, if some error occurs before the query completes or is aborted by
8065 ** the callback, an SQLite error code is returned.
8068 ** xSetAuxdata(pFts5, pAux, xDelete)
8070 ** Save the pointer passed as the second argument as the extension functions
8071 ** "auxiliary data". The pointer may then be retrieved by the current or any
8072 ** future invocation of the same fts5 extension function made as part of
8073 ** of the same MATCH query using the xGetAuxdata() API.
8075 ** Each extension function is allocated a single auxiliary data slot for
8076 ** each FTS query (MATCH expression). If the extension function is invoked
8077 ** more than once for a single FTS query, then all invocations share a
8078 ** single auxiliary data context.
8080 ** If there is already an auxiliary data pointer when this function is
8081 ** invoked, then it is replaced by the new pointer. If an xDelete callback
8082 ** was specified along with the original pointer, it is invoked at this
8085 ** The xDelete callback, if one is specified, is also invoked on the
8086 ** auxiliary data pointer after the FTS5 query has finished.
8088 ** If an error (e.g. an OOM condition) occurs within this function, an
8089 ** the auxiliary data is set to NULL and an error code returned. If the
8090 ** xDelete parameter was not NULL, it is invoked on the auxiliary data
8091 ** pointer before returning.
8094 ** xGetAuxdata(pFts5, bClear)
8096 ** Returns the current auxiliary data pointer for the fts5 extension
8097 ** function. See the xSetAuxdata() method for details.
8099 ** If the bClear argument is non-zero, then the auxiliary data is cleared
8100 ** (set to NULL) before this function returns. In this case the xDelete,
8101 ** if any, is not invoked.
8104 ** xRowCount(pFts5, pnRow)
8106 ** This function is used to retrieve the total number of rows in the table.
8107 ** In other words, the same value that would be returned by:
8109 ** SELECT count(*) FROM ftstable;
8112 ** This function is used, along with type Fts5PhraseIter and the xPhraseNext
8113 ** method, to iterate through all instances of a single query phrase within
8114 ** the current row. This is the same information as is accessible via the
8115 ** xInstCount/xInst APIs. While the xInstCount/xInst APIs are more convenient
8116 ** to use, this API may be faster under some circumstances. To iterate
8117 ** through instances of phrase iPhrase, use the following code:
8119 ** Fts5PhraseIter iter;
8121 ** for(pApi->xPhraseFirst(pFts, iPhrase, &iter, &iCol, &iOff);
8123 ** pApi->xPhraseNext(pFts, &iter, &iCol, &iOff)
8125 ** // An instance of phrase iPhrase at offset iOff of column iCol
8128 ** The Fts5PhraseIter structure is defined above. Applications should not
8129 ** modify this structure directly - it should only be used as shown above
8130 ** with the xPhraseFirst() and xPhraseNext() API methods.
8133 ** See xPhraseFirst above.
8135 struct Fts5ExtensionApi {
8136 int iVersion; /* Currently always set to 1 */
8138 void *(*xUserData)(Fts5Context*);
8140 int (*xColumnCount)(Fts5Context*);
8141 int (*xRowCount)(Fts5Context*, sqlite3_int64 *pnRow);
8142 int (*xColumnTotalSize)(Fts5Context*, int iCol, sqlite3_int64 *pnToken);
8144 int (*xTokenize)(Fts5Context*,
8145 const char *pText, int nText, /* Text to tokenize */
8146 void *pCtx, /* Context passed to xToken() */
8147 int (*xToken)(void*, int, const char*, int, int, int) /* Callback */
8150 int (*xPhraseCount)(Fts5Context*);
8151 int (*xPhraseSize)(Fts5Context*, int iPhrase);
8153 int (*xInstCount)(Fts5Context*, int *pnInst);
8154 int (*xInst)(Fts5Context*, int iIdx, int *piPhrase, int *piCol, int *piOff);
8156 sqlite3_int64 (*xRowid)(Fts5Context*);
8157 int (*xColumnText)(Fts5Context*, int iCol, const char **pz, int *pn);
8158 int (*xColumnSize)(Fts5Context*, int iCol, int *pnToken);
8160 int (*xQueryPhrase)(Fts5Context*, int iPhrase, void *pUserData,
8161 int(*)(const Fts5ExtensionApi*,Fts5Context*,void*)
8163 int (*xSetAuxdata)(Fts5Context*, void *pAux, void(*xDelete)(void*));
8164 void *(*xGetAuxdata)(Fts5Context*, int bClear);
8166 void (*xPhraseFirst)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*, int*);
8167 void (*xPhraseNext)(Fts5Context*, Fts5PhraseIter*, int *piCol, int *piOff);
8171 ** CUSTOM AUXILIARY FUNCTIONS
8172 *************************************************************************/
8174 /*************************************************************************
8175 ** CUSTOM TOKENIZERS
8177 ** Applications may also register custom tokenizer types. A tokenizer
8178 ** is registered by providing fts5 with a populated instance of the
8179 ** following structure. All structure methods must be defined, setting
8180 ** any member of the fts5_tokenizer struct to NULL leads to undefined
8181 ** behaviour. The structure methods are expected to function as follows:
8184 ** This function is used to allocate and inititalize a tokenizer instance.
8185 ** A tokenizer instance is required to actually tokenize text.
8187 ** The first argument passed to this function is a copy of the (void*)
8188 ** pointer provided by the application when the fts5_tokenizer object
8189 ** was registered with FTS5 (the third argument to xCreateTokenizer()).
8190 ** The second and third arguments are an array of nul-terminated strings
8191 ** containing the tokenizer arguments, if any, specified following the
8192 ** tokenizer name as part of the CREATE VIRTUAL TABLE statement used
8193 ** to create the FTS5 table.
8195 ** The final argument is an output variable. If successful, (*ppOut)
8196 ** should be set to point to the new tokenizer handle and SQLITE_OK
8197 ** returned. If an error occurs, some value other than SQLITE_OK should
8198 ** be returned. In this case, fts5 assumes that the final value of *ppOut
8202 ** This function is invoked to delete a tokenizer handle previously
8203 ** allocated using xCreate(). Fts5 guarantees that this function will
8204 ** be invoked exactly once for each successful call to xCreate().
8207 ** This function is expected to tokenize the nText byte string indicated
8208 ** by argument pText. pText may or may not be nul-terminated. The first
8209 ** argument passed to this function is a pointer to an Fts5Tokenizer object
8210 ** returned by an earlier call to xCreate().
8212 ** The second argument indicates the reason that FTS5 is requesting
8213 ** tokenization of the supplied text. This is always one of the following
8216 ** <ul><li> <b>FTS5_TOKENIZE_DOCUMENT</b> - A document is being inserted into
8217 ** or removed from the FTS table. The tokenizer is being invoked to
8218 ** determine the set of tokens to add to (or delete from) the
8221 ** <li> <b>FTS5_TOKENIZE_QUERY</b> - A MATCH query is being executed
8222 ** against the FTS index. The tokenizer is being called to tokenize
8223 ** a bareword or quoted string specified as part of the query.
8225 ** <li> <b>(FTS5_TOKENIZE_QUERY | FTS5_TOKENIZE_PREFIX)</b> - Same as
8226 ** FTS5_TOKENIZE_QUERY, except that the bareword or quoted string is
8227 ** followed by a "*" character, indicating that the last token
8228 ** returned by the tokenizer will be treated as a token prefix.
8230 ** <li> <b>FTS5_TOKENIZE_AUX</b> - The tokenizer is being invoked to
8231 ** satisfy an fts5_api.xTokenize() request made by an auxiliary
8232 ** function. Or an fts5_api.xColumnSize() request made by the same
8233 ** on a columnsize=0 database.
8236 ** For each token in the input string, the supplied callback xToken() must
8237 ** be invoked. The first argument to it should be a copy of the pointer
8238 ** passed as the second argument to xTokenize(). The third and fourth
8239 ** arguments are a pointer to a buffer containing the token text, and the
8240 ** size of the token in bytes. The 4th and 5th arguments are the byte offsets
8241 ** of the first byte of and first byte immediately following the text from
8242 ** which the token is derived within the input.
8244 ** The second argument passed to the xToken() callback ("tflags") should
8245 ** normally be set to 0. The exception is if the tokenizer supports
8246 ** synonyms. In this case see the discussion below for details.
8248 ** FTS5 assumes the xToken() callback is invoked for each token in the
8249 ** order that they occur within the input text.
8251 ** If an xToken() callback returns any value other than SQLITE_OK, then
8252 ** the tokenization should be abandoned and the xTokenize() method should
8253 ** immediately return a copy of the xToken() return value. Or, if the
8254 ** input buffer is exhausted, xTokenize() should return SQLITE_OK. Finally,
8255 ** if an error occurs with the xTokenize() implementation itself, it
8256 ** may abandon the tokenization and return any error code other than
8257 ** SQLITE_OK or SQLITE_DONE.
8261 ** Custom tokenizers may also support synonyms. Consider a case in which a
8262 ** user wishes to query for a phrase such as "first place". Using the
8263 ** built-in tokenizers, the FTS5 query 'first + place' will match instances
8264 ** of "first place" within the document set, but not alternative forms
8265 ** such as "1st place". In some applications, it would be better to match
8266 ** all instances of "first place" or "1st place" regardless of which form
8267 ** the user specified in the MATCH query text.
8269 ** There are several ways to approach this in FTS5:
8271 ** <ol><li> By mapping all synonyms to a single token. In this case, the
8272 ** In the above example, this means that the tokenizer returns the
8273 ** same token for inputs "first" and "1st". Say that token is in
8274 ** fact "first", so that when the user inserts the document "I won
8275 ** 1st place" entries are added to the index for tokens "i", "won",
8276 ** "first" and "place". If the user then queries for '1st + place',
8277 ** the tokenizer substitutes "first" for "1st" and the query works
8280 ** <li> By adding multiple synonyms for a single term to the FTS index.
8281 ** In this case, when tokenizing query text, the tokenizer may
8282 ** provide multiple synonyms for a single term within the document.
8283 ** FTS5 then queries the index for each synonym individually. For
8284 ** example, faced with the query:
8287 ** ... MATCH 'first place'</codeblock>
8289 ** the tokenizer offers both "1st" and "first" as synonyms for the
8290 ** first token in the MATCH query and FTS5 effectively runs a query
8294 ** ... MATCH '(first OR 1st) place'</codeblock>
8296 ** except that, for the purposes of auxiliary functions, the query
8297 ** still appears to contain just two phrases - "(first OR 1st)"
8298 ** being treated as a single phrase.
8300 ** <li> By adding multiple synonyms for a single term to the FTS index.
8301 ** Using this method, when tokenizing document text, the tokenizer
8302 ** provides multiple synonyms for each token. So that when a
8303 ** document such as "I won first place" is tokenized, entries are
8304 ** added to the FTS index for "i", "won", "first", "1st" and
8307 ** This way, even if the tokenizer does not provide synonyms
8308 ** when tokenizing query text (it should not - to do would be
8309 ** inefficient), it doesn't matter if the user queries for
8310 ** 'first + place' or '1st + place', as there are entires in the
8311 ** FTS index corresponding to both forms of the first token.
8314 ** Whether it is parsing document or query text, any call to xToken that
8315 ** specifies a <i>tflags</i> argument with the FTS5_TOKEN_COLOCATED bit
8316 ** is considered to supply a synonym for the previous token. For example,
8317 ** when parsing the document "I won first place", a tokenizer that supports
8318 ** synonyms would call xToken() 5 times, as follows:
8321 ** xToken(pCtx, 0, "i", 1, 0, 1);
8322 ** xToken(pCtx, 0, "won", 3, 2, 5);
8323 ** xToken(pCtx, 0, "first", 5, 6, 11);
8324 ** xToken(pCtx, FTS5_TOKEN_COLOCATED, "1st", 3, 6, 11);
8325 ** xToken(pCtx, 0, "place", 5, 12, 17);
8328 ** It is an error to specify the FTS5_TOKEN_COLOCATED flag the first time
8329 ** xToken() is called. Multiple synonyms may be specified for a single token
8330 ** by making multiple calls to xToken(FTS5_TOKEN_COLOCATED) in sequence.
8331 ** There is no limit to the number of synonyms that may be provided for a
8334 ** In many cases, method (1) above is the best approach. It does not add
8335 ** extra data to the FTS index or require FTS5 to query for multiple terms,
8336 ** so it is efficient in terms of disk space and query speed. However, it
8337 ** does not support prefix queries very well. If, as suggested above, the
8338 ** token "first" is subsituted for "1st" by the tokenizer, then the query:
8341 ** ... MATCH '1s*'</codeblock>
8343 ** will not match documents that contain the token "1st" (as the tokenizer
8344 ** will probably not map "1s" to any prefix of "first").
8346 ** For full prefix support, method (3) may be preferred. In this case,
8347 ** because the index contains entries for both "first" and "1st", prefix
8348 ** queries such as 'fi*' or '1s*' will match correctly. However, because
8349 ** extra entries are added to the FTS index, this method uses more space
8350 ** within the database.
8352 ** Method (2) offers a midpoint between (1) and (3). Using this method,
8353 ** a query such as '1s*' will match documents that contain the literal
8354 ** token "1st", but not "first" (assuming the tokenizer is not able to
8355 ** provide synonyms for prefixes). However, a non-prefix query like '1st'
8356 ** will match against "1st" and "first". This method does not require
8357 ** extra disk space, as no extra entries are added to the FTS index.
8358 ** On the other hand, it may require more CPU cycles to run MATCH queries,
8359 ** as separate queries of the FTS index are required for each synonym.
8361 ** When using methods (2) or (3), it is important that the tokenizer only
8362 ** provide synonyms when tokenizing document text (method (2)) or query
8363 ** text (method (3)), not both. Doing so will not cause any errors, but is
8366 typedef struct Fts5Tokenizer Fts5Tokenizer;
8367 typedef struct fts5_tokenizer fts5_tokenizer;
8368 struct fts5_tokenizer {
8369 int (*xCreate)(void*, const char **azArg, int nArg, Fts5Tokenizer **ppOut);
8370 void (*xDelete)(Fts5Tokenizer*);
8371 int (*xTokenize)(Fts5Tokenizer*,
8373 int flags, /* Mask of FTS5_TOKENIZE_* flags */
8374 const char *pText, int nText,
8376 void *pCtx, /* Copy of 2nd argument to xTokenize() */
8377 int tflags, /* Mask of FTS5_TOKEN_* flags */
8378 const char *pToken, /* Pointer to buffer containing token */
8379 int nToken, /* Size of token in bytes */
8380 int iStart, /* Byte offset of token within input text */
8381 int iEnd /* Byte offset of end of token within input text */
8386 /* Flags that may be passed as the third argument to xTokenize() */
8387 #define FTS5_TOKENIZE_QUERY 0x0001
8388 #define FTS5_TOKENIZE_PREFIX 0x0002
8389 #define FTS5_TOKENIZE_DOCUMENT 0x0004
8390 #define FTS5_TOKENIZE_AUX 0x0008
8392 /* Flags that may be passed by the tokenizer implementation back to FTS5
8393 ** as the third argument to the supplied xToken callback. */
8394 #define FTS5_TOKEN_COLOCATED 0x0001 /* Same position as prev. token */
8397 ** END OF CUSTOM TOKENIZERS
8398 *************************************************************************/
8400 /*************************************************************************
8401 ** FTS5 EXTENSION REGISTRATION API
8403 typedef struct fts5_api fts5_api;
8405 int iVersion; /* Currently always set to 2 */
8407 /* Create a new tokenizer */
8408 int (*xCreateTokenizer)(
8412 fts5_tokenizer *pTokenizer,
8413 void (*xDestroy)(void*)
8416 /* Find an existing tokenizer */
8417 int (*xFindTokenizer)(
8421 fts5_tokenizer *pTokenizer
8424 /* Create a new auxiliary function */
8425 int (*xCreateFunction)(
8429 fts5_extension_function xFunction,
8430 void (*xDestroy)(void*)
8435 ** END OF REGISTRATION API
8436 *************************************************************************/
8439 } /* end of the 'extern "C"' block */
8442 #endif /* _FTS5_H */