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 suppose 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 ** Add the ability to override 'extern'
49 # define SQLITE_EXTERN extern
58 ** These no-op macros are used in front of interfaces to mark those
59 ** interfaces as either deprecated or experimental. New applications
60 ** should not use deprecated interfaces - they are supported for backwards
61 ** compatibility only. Application writers should be aware that
62 ** experimental interfaces are subject to change in point releases.
64 ** These macros used to resolve to various kinds of compiler magic that
65 ** would generate warning messages when they were used. But that
66 ** compiler magic ended up generating such a flurry of bug reports
67 ** that we have taken it all out and gone back to using simple
70 #define SQLITE_DEPRECATED
71 #define SQLITE_EXPERIMENTAL
74 ** Ensure these symbols were not defined by some previous header file.
77 # undef SQLITE_VERSION
79 #ifdef SQLITE_VERSION_NUMBER
80 # undef SQLITE_VERSION_NUMBER
84 ** CAPI3REF: Compile-Time Library Version Numbers
86 ** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header
87 ** evaluates to a string literal that is the SQLite version in the
88 ** format "X.Y.Z" where X is the major version number (always 3 for
89 ** SQLite3) and Y is the minor version number and Z is the release number.)^
90 ** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer
91 ** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same
92 ** numbers used in [SQLITE_VERSION].)^
93 ** The SQLITE_VERSION_NUMBER for any given release of SQLite will also
94 ** be larger than the release from which it is derived. Either Y will
95 ** be held constant and Z will be incremented or else Y will be incremented
96 ** and Z will be reset to zero.
98 ** Since version 3.6.18, SQLite source code has been stored in the
99 ** <a href="http://www.fossil-scm.org/">Fossil configuration management
100 ** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to
101 ** a string which identifies a particular check-in of SQLite
102 ** within its configuration management system. ^The SQLITE_SOURCE_ID
103 ** string contains the date and time of the check-in (UTC) and an SHA1
104 ** hash of the entire source tree.
106 ** See also: [sqlite3_libversion()],
107 ** [sqlite3_libversion_number()], [sqlite3_sourceid()],
108 ** [sqlite_version()] and [sqlite_source_id()].
110 #define SQLITE_VERSION "3.8.8.3+"
111 #define SQLITE_VERSION_NUMBER 3008008
112 #define SQLITE_SOURCE_ID "2015-02-25 13:29:11 9d6c1880fb75660bbabd693175579529785f8a6b"
115 ** CAPI3REF: Run-Time Library Version Numbers
116 ** KEYWORDS: sqlite3_version, sqlite3_sourceid
118 ** These interfaces provide the same information as the [SQLITE_VERSION],
119 ** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros
120 ** but are associated with the library instead of the header file. ^(Cautious
121 ** programmers might include assert() statements in their application to
122 ** verify that values returned by these interfaces match the macros in
123 ** the header, and thus insure that the application is
124 ** compiled with matching library and header files.
127 ** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
128 ** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 );
129 ** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
130 ** </pre></blockquote>)^
132 ** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION]
133 ** macro. ^The sqlite3_libversion() function returns a pointer to the
134 ** to the sqlite3_version[] string constant. The sqlite3_libversion()
135 ** function is provided for use in DLLs since DLL users usually do not have
136 ** direct access to string constants within the DLL. ^The
137 ** sqlite3_libversion_number() function returns an integer equal to
138 ** [SQLITE_VERSION_NUMBER]. ^The sqlite3_sourceid() function returns
139 ** a pointer to a string constant whose value is the same as the
140 ** [SQLITE_SOURCE_ID] C preprocessor macro.
142 ** See also: [sqlite_version()] and [sqlite_source_id()].
144 SQLITE_API SQLITE_EXTERN const char sqlite3_version[];
145 SQLITE_API const char *sqlite3_libversion(void);
146 SQLITE_API const char *sqlite3_sourceid(void);
147 SQLITE_API int sqlite3_libversion_number(void);
150 ** CAPI3REF: Run-Time Library Compilation Options Diagnostics
152 ** ^The sqlite3_compileoption_used() function returns 0 or 1
153 ** indicating whether the specified option was defined at
154 ** compile time. ^The SQLITE_ prefix may be omitted from the
155 ** option name passed to sqlite3_compileoption_used().
157 ** ^The sqlite3_compileoption_get() function allows iterating
158 ** over the list of options that were defined at compile time by
159 ** returning the N-th compile time option string. ^If N is out of range,
160 ** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_
161 ** prefix is omitted from any strings returned by
162 ** sqlite3_compileoption_get().
164 ** ^Support for the diagnostic functions sqlite3_compileoption_used()
165 ** and sqlite3_compileoption_get() may be omitted by specifying the
166 ** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time.
168 ** See also: SQL functions [sqlite_compileoption_used()] and
169 ** [sqlite_compileoption_get()] and the [compile_options pragma].
171 #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
172 SQLITE_API int sqlite3_compileoption_used(const char *zOptName);
173 SQLITE_API const char *sqlite3_compileoption_get(int N);
177 ** CAPI3REF: Test To See If The Library Is Threadsafe
179 ** ^The sqlite3_threadsafe() function returns zero if and only if
180 ** SQLite was compiled with mutexing code omitted due to the
181 ** [SQLITE_THREADSAFE] compile-time option being set to 0.
183 ** SQLite can be compiled with or without mutexes. When
184 ** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
185 ** are enabled and SQLite is threadsafe. When the
186 ** [SQLITE_THREADSAFE] macro is 0,
187 ** the mutexes are omitted. Without the mutexes, it is not safe
188 ** to use SQLite concurrently from more than one thread.
190 ** Enabling mutexes incurs a measurable performance penalty.
191 ** So if speed is of utmost importance, it makes sense to disable
192 ** the mutexes. But for maximum safety, mutexes should be enabled.
193 ** ^The default behavior is for mutexes to be enabled.
195 ** This interface can be used by an application to make sure that the
196 ** version of SQLite that it is linking against was compiled with
197 ** the desired setting of the [SQLITE_THREADSAFE] macro.
199 ** This interface only reports on the compile-time mutex setting
200 ** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with
201 ** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
202 ** can be fully or partially disabled using a call to [sqlite3_config()]
203 ** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD],
204 ** or [SQLITE_CONFIG_SERIALIZED]. ^(The return value of the
205 ** sqlite3_threadsafe() function shows only the compile-time setting of
206 ** thread safety, not any run-time changes to that setting made by
207 ** sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
208 ** is unchanged by calls to sqlite3_config().)^
210 ** See the [threading mode] documentation for additional information.
212 SQLITE_API int sqlite3_threadsafe(void);
215 ** CAPI3REF: Database Connection Handle
216 ** KEYWORDS: {database connection} {database connections}
218 ** Each open SQLite database is represented by a pointer to an instance of
219 ** the opaque structure named "sqlite3". It is useful to think of an sqlite3
220 ** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and
221 ** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
222 ** and [sqlite3_close_v2()] are its destructors. There are many other
223 ** interfaces (such as
224 ** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
225 ** [sqlite3_busy_timeout()] to name but three) that are methods on an
228 typedef struct sqlite3 sqlite3;
231 ** CAPI3REF: 64-Bit Integer Types
232 ** KEYWORDS: sqlite_int64 sqlite_uint64
234 ** Because there is no cross-platform way to specify 64-bit integer types
235 ** SQLite includes typedefs for 64-bit signed and unsigned integers.
237 ** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
238 ** The sqlite_int64 and sqlite_uint64 types are supported for backwards
239 ** compatibility only.
241 ** ^The sqlite3_int64 and sqlite_int64 types can store integer values
242 ** between -9223372036854775808 and +9223372036854775807 inclusive. ^The
243 ** sqlite3_uint64 and sqlite_uint64 types can store integer values
244 ** between 0 and +18446744073709551615 inclusive.
246 #ifdef SQLITE_INT64_TYPE
247 typedef SQLITE_INT64_TYPE sqlite_int64;
248 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
249 #elif defined(_MSC_VER) || defined(__BORLANDC__)
250 typedef __int64 sqlite_int64;
251 typedef unsigned __int64 sqlite_uint64;
253 typedef long long int sqlite_int64;
254 typedef unsigned long long int sqlite_uint64;
256 typedef sqlite_int64 sqlite3_int64;
257 typedef sqlite_uint64 sqlite3_uint64;
260 ** If compiling for a processor that lacks floating point support,
261 ** substitute integer for floating-point.
263 #ifdef SQLITE_OMIT_FLOATING_POINT
264 # define double sqlite3_int64
268 ** CAPI3REF: Closing A Database Connection
270 ** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors
271 ** for the [sqlite3] object.
272 ** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if
273 ** the [sqlite3] object is successfully destroyed and all associated
274 ** resources are deallocated.
276 ** ^If the database connection is associated with unfinalized prepared
277 ** statements or unfinished sqlite3_backup objects then sqlite3_close()
278 ** will leave the database connection open and return [SQLITE_BUSY].
279 ** ^If sqlite3_close_v2() is called with unfinalized prepared statements
280 ** and/or unfinished sqlite3_backups, then the database connection becomes
281 ** an unusable "zombie" which will automatically be deallocated when the
282 ** last prepared statement is finalized or the last sqlite3_backup is
283 ** finished. The sqlite3_close_v2() interface is intended for use with
284 ** host languages that are garbage collected, and where the order in which
285 ** destructors are called is arbitrary.
287 ** Applications should [sqlite3_finalize | finalize] all [prepared statements],
288 ** [sqlite3_blob_close | close] all [BLOB handles], and
289 ** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated
290 ** with the [sqlite3] object prior to attempting to close the object. ^If
291 ** sqlite3_close_v2() is called on a [database connection] that still has
292 ** outstanding [prepared statements], [BLOB handles], and/or
293 ** [sqlite3_backup] objects then it returns [SQLITE_OK] and the deallocation
294 ** of resources is deferred until all [prepared statements], [BLOB handles],
295 ** and [sqlite3_backup] objects are also destroyed.
297 ** ^If an [sqlite3] object is destroyed while a transaction is open,
298 ** the transaction is automatically rolled back.
300 ** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)]
301 ** must be either a NULL
302 ** pointer or an [sqlite3] object pointer obtained
303 ** from [sqlite3_open()], [sqlite3_open16()], or
304 ** [sqlite3_open_v2()], and not previously closed.
305 ** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer
306 ** argument is a harmless no-op.
308 SQLITE_API int sqlite3_close(sqlite3*);
309 SQLITE_API int sqlite3_close_v2(sqlite3*);
312 ** The type for a callback function.
313 ** This is legacy and deprecated. It is included for historical
314 ** compatibility and is not documented.
316 typedef int (*sqlite3_callback)(void*,int,char**, char**);
319 ** CAPI3REF: One-Step Query Execution Interface
321 ** The sqlite3_exec() interface is a convenience wrapper around
322 ** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
323 ** that allows an application to run multiple statements of SQL
324 ** without having to use a lot of C code.
326 ** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
327 ** semicolon-separate SQL statements passed into its 2nd argument,
328 ** in the context of the [database connection] passed in as its 1st
329 ** argument. ^If the callback function of the 3rd argument to
330 ** sqlite3_exec() is not NULL, then it is invoked for each result row
331 ** coming out of the evaluated SQL statements. ^The 4th argument to
332 ** sqlite3_exec() is relayed through to the 1st argument of each
333 ** callback invocation. ^If the callback pointer to sqlite3_exec()
334 ** is NULL, then no callback is ever invoked and result rows are
337 ** ^If an error occurs while evaluating the SQL statements passed into
338 ** sqlite3_exec(), then execution of the current statement stops and
339 ** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec()
340 ** is not NULL then any error message is written into memory obtained
341 ** from [sqlite3_malloc()] and passed back through the 5th parameter.
342 ** To avoid memory leaks, the application should invoke [sqlite3_free()]
343 ** on error message strings returned through the 5th parameter of
344 ** of sqlite3_exec() after the error message string is no longer needed.
345 ** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
346 ** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
347 ** NULL before returning.
349 ** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
350 ** routine returns SQLITE_ABORT without invoking the callback again and
351 ** without running any subsequent SQL statements.
353 ** ^The 2nd argument to the sqlite3_exec() callback function is the
354 ** number of columns in the result. ^The 3rd argument to the sqlite3_exec()
355 ** callback is an array of pointers to strings obtained as if from
356 ** [sqlite3_column_text()], one for each column. ^If an element of a
357 ** result row is NULL then the corresponding string pointer for the
358 ** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the
359 ** sqlite3_exec() callback is an array of pointers to strings where each
360 ** entry represents the name of corresponding result column as obtained
361 ** from [sqlite3_column_name()].
363 ** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
364 ** to an empty string, or a pointer that contains only whitespace and/or
365 ** SQL comments, then no SQL statements are evaluated and the database
371 ** <li> The application must insure that the 1st parameter to sqlite3_exec()
372 ** is a valid and open [database connection].
373 ** <li> The application must not close the [database connection] specified by
374 ** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
375 ** <li> The application must not modify the SQL statement text passed into
376 ** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
379 SQLITE_API int sqlite3_exec(
380 sqlite3*, /* An open database */
381 const char *sql, /* SQL to be evaluated */
382 int (*callback)(void*,int,char**,char**), /* Callback function */
383 void *, /* 1st argument to callback */
384 char **errmsg /* Error msg written here */
388 ** CAPI3REF: Result Codes
389 ** KEYWORDS: {result code definitions}
391 ** Many SQLite functions return an integer result code from the set shown
392 ** here in order to indicate success or failure.
394 ** New error codes may be added in future versions of SQLite.
396 ** See also: [extended result code definitions]
398 #define SQLITE_OK 0 /* Successful result */
399 /* beginning-of-error-codes */
400 #define SQLITE_ERROR 1 /* SQL error or missing database */
401 #define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */
402 #define SQLITE_PERM 3 /* Access permission denied */
403 #define SQLITE_ABORT 4 /* Callback routine requested an abort */
404 #define SQLITE_BUSY 5 /* The database file is locked */
405 #define SQLITE_LOCKED 6 /* A table in the database is locked */
406 #define SQLITE_NOMEM 7 /* A malloc() failed */
407 #define SQLITE_READONLY 8 /* Attempt to write a readonly database */
408 #define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/
409 #define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */
410 #define SQLITE_CORRUPT 11 /* The database disk image is malformed */
411 #define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */
412 #define SQLITE_FULL 13 /* Insertion failed because database is full */
413 #define SQLITE_CANTOPEN 14 /* Unable to open the database file */
414 #define SQLITE_PROTOCOL 15 /* Database lock protocol error */
415 #define SQLITE_EMPTY 16 /* Database is empty */
416 #define SQLITE_SCHEMA 17 /* The database schema changed */
417 #define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */
418 #define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */
419 #define SQLITE_MISMATCH 20 /* Data type mismatch */
420 #define SQLITE_MISUSE 21 /* Library used incorrectly */
421 #define SQLITE_NOLFS 22 /* Uses OS features not supported on host */
422 #define SQLITE_AUTH 23 /* Authorization denied */
423 #define SQLITE_FORMAT 24 /* Auxiliary database format error */
424 #define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */
425 #define SQLITE_NOTADB 26 /* File opened that is not a database file */
426 #define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */
427 #define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */
428 #define SQLITE_ROW 100 /* sqlite3_step() has another row ready */
429 #define SQLITE_DONE 101 /* sqlite3_step() has finished executing */
430 /* end-of-error-codes */
433 ** CAPI3REF: Extended Result Codes
434 ** KEYWORDS: {extended result code definitions}
436 ** In its default configuration, SQLite API routines return one of 30 integer
437 ** [result codes]. However, experience has shown that many of
438 ** these result codes are too coarse-grained. They do not provide as
439 ** much information about problems as programmers might like. In an effort to
440 ** address this, newer versions of SQLite (version 3.3.8 and later) include
441 ** support for additional result codes that provide more detailed information
442 ** about errors. These [extended result codes] are enabled or disabled
443 ** on a per database connection basis using the
444 ** [sqlite3_extended_result_codes()] API. Or, the extended code for
445 ** the most recent error can be obtained using
446 ** [sqlite3_extended_errcode()].
448 #define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8))
449 #define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8))
450 #define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8))
451 #define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8))
452 #define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8))
453 #define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8))
454 #define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8))
455 #define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8))
456 #define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8))
457 #define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8))
458 #define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8))
459 #define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8))
460 #define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8))
461 #define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
462 #define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8))
463 #define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8))
464 #define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8))
465 #define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8))
466 #define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8))
467 #define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8))
468 #define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8))
469 #define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8))
470 #define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8))
471 #define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8))
472 #define SQLITE_IOERR_GETTEMPPATH (SQLITE_IOERR | (25<<8))
473 #define SQLITE_IOERR_CONVPATH (SQLITE_IOERR | (26<<8))
474 #define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8))
475 #define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8))
476 #define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY | (2<<8))
477 #define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8))
478 #define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8))
479 #define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8))
480 #define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN | (4<<8))
481 #define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8))
482 #define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8))
483 #define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8))
484 #define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8))
485 #define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8))
486 #define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8))
487 #define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8))
488 #define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8))
489 #define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8))
490 #define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8))
491 #define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8))
492 #define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8))
493 #define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8))
494 #define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8))
495 #define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8))
496 #define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT |(10<<8))
497 #define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8))
498 #define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8))
499 #define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING | (1<<8))
500 #define SQLITE_AUTH_USER (SQLITE_AUTH | (1<<8))
503 ** CAPI3REF: Flags For File Open Operations
505 ** These bit values are intended for use in the
506 ** 3rd parameter to the [sqlite3_open_v2()] interface and
507 ** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
509 #define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */
510 #define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */
511 #define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */
512 #define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */
513 #define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */
514 #define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */
515 #define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */
516 #define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */
517 #define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */
518 #define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */
519 #define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */
520 #define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */
521 #define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */
522 #define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */
523 #define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */
524 #define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */
525 #define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */
526 #define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */
527 #define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */
528 #define SQLITE_OPEN_WAL 0x00080000 /* VFS only */
530 /* Reserved: 0x00F00000 */
533 ** CAPI3REF: Device Characteristics
535 ** The xDeviceCharacteristics method of the [sqlite3_io_methods]
536 ** object returns an integer which is a vector of these
537 ** bit values expressing I/O characteristics of the mass storage
538 ** device that holds the file that the [sqlite3_io_methods]
541 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
542 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
543 ** mean that writes of blocks that are nnn bytes in size and
544 ** are aligned to an address which is an integer multiple of
545 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
546 ** that when data is appended to a file, the data is appended
547 ** first then the size of the file is extended, never the other
548 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
549 ** information is written to disk in the same order as calls
550 ** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
551 ** after reboot following a crash or power loss, the only bytes in a
552 ** file that were written at the application level might have changed
553 ** and that adjacent bytes, even bytes within the same sector are
554 ** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN
555 ** flag indicate that a file cannot be deleted when open. The
556 ** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on
557 ** read-only media and cannot be changed even by processes with
558 ** elevated privileges.
560 #define SQLITE_IOCAP_ATOMIC 0x00000001
561 #define SQLITE_IOCAP_ATOMIC512 0x00000002
562 #define SQLITE_IOCAP_ATOMIC1K 0x00000004
563 #define SQLITE_IOCAP_ATOMIC2K 0x00000008
564 #define SQLITE_IOCAP_ATOMIC4K 0x00000010
565 #define SQLITE_IOCAP_ATOMIC8K 0x00000020
566 #define SQLITE_IOCAP_ATOMIC16K 0x00000040
567 #define SQLITE_IOCAP_ATOMIC32K 0x00000080
568 #define SQLITE_IOCAP_ATOMIC64K 0x00000100
569 #define SQLITE_IOCAP_SAFE_APPEND 0x00000200
570 #define SQLITE_IOCAP_SEQUENTIAL 0x00000400
571 #define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800
572 #define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000
573 #define SQLITE_IOCAP_IMMUTABLE 0x00002000
576 ** CAPI3REF: File Locking Levels
578 ** SQLite uses one of these integer values as the second
579 ** argument to calls it makes to the xLock() and xUnlock() methods
580 ** of an [sqlite3_io_methods] object.
582 #define SQLITE_LOCK_NONE 0
583 #define SQLITE_LOCK_SHARED 1
584 #define SQLITE_LOCK_RESERVED 2
585 #define SQLITE_LOCK_PENDING 3
586 #define SQLITE_LOCK_EXCLUSIVE 4
589 ** CAPI3REF: Synchronization Type Flags
591 ** When SQLite invokes the xSync() method of an
592 ** [sqlite3_io_methods] object it uses a combination of
593 ** these integer values as the second argument.
595 ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
596 ** sync operation only needs to flush data to mass storage. Inode
597 ** information need not be flushed. If the lower four bits of the flag
598 ** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
599 ** If the lower four bits equal SQLITE_SYNC_FULL, that means
600 ** to use Mac OS X style fullsync instead of fsync().
602 ** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
603 ** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
604 ** settings. The [synchronous pragma] determines when calls to the
605 ** xSync VFS method occur and applies uniformly across all platforms.
606 ** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
607 ** energetic or rigorous or forceful the sync operations are and
608 ** only make a difference on Mac OSX for the default SQLite code.
609 ** (Third-party VFS implementations might also make the distinction
610 ** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
611 ** operating systems natively supported by SQLite, only Mac OSX
612 ** cares about the difference.)
614 #define SQLITE_SYNC_NORMAL 0x00002
615 #define SQLITE_SYNC_FULL 0x00003
616 #define SQLITE_SYNC_DATAONLY 0x00010
619 ** CAPI3REF: OS Interface Open File Handle
621 ** An [sqlite3_file] object represents an open file in the
622 ** [sqlite3_vfs | OS interface layer]. Individual OS interface
623 ** implementations will
624 ** want to subclass this object by appending additional fields
625 ** for their own use. The pMethods entry is a pointer to an
626 ** [sqlite3_io_methods] object that defines methods for performing
627 ** I/O operations on the open file.
629 typedef struct sqlite3_file sqlite3_file;
630 struct sqlite3_file {
631 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */
635 ** CAPI3REF: OS Interface File Virtual Methods Object
637 ** Every file opened by the [sqlite3_vfs.xOpen] method populates an
638 ** [sqlite3_file] object (or, more commonly, a subclass of the
639 ** [sqlite3_file] object) with a pointer to an instance of this object.
640 ** This object defines the methods used to perform various operations
641 ** against the open file represented by the [sqlite3_file] object.
643 ** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element
644 ** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
645 ** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The
646 ** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
647 ** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
650 ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
651 ** [SQLITE_SYNC_FULL]. The first choice is the normal fsync().
652 ** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY]
653 ** flag may be ORed in to indicate that only the data of the file
654 ** and not its inode needs to be synced.
656 ** The integer values to xLock() and xUnlock() are one of
658 ** <li> [SQLITE_LOCK_NONE],
659 ** <li> [SQLITE_LOCK_SHARED],
660 ** <li> [SQLITE_LOCK_RESERVED],
661 ** <li> [SQLITE_LOCK_PENDING], or
662 ** <li> [SQLITE_LOCK_EXCLUSIVE].
664 ** xLock() increases the lock. xUnlock() decreases the lock.
665 ** The xCheckReservedLock() method checks whether any database connection,
666 ** either in this process or in some other process, is holding a RESERVED,
667 ** PENDING, or EXCLUSIVE lock on the file. It returns true
668 ** if such a lock exists and false otherwise.
670 ** The xFileControl() method is a generic interface that allows custom
671 ** VFS implementations to directly control an open file using the
672 ** [sqlite3_file_control()] interface. The second "op" argument is an
673 ** integer opcode. The third argument is a generic pointer intended to
674 ** point to a structure that may contain arguments or space in which to
675 ** write return values. Potential uses for xFileControl() might be
676 ** functions to enable blocking locks with timeouts, to change the
677 ** locking strategy (for example to use dot-file locks), to inquire
678 ** about the status of a lock, or to break stale locks. The SQLite
679 ** core reserves all opcodes less than 100 for its own use.
680 ** A [file control opcodes | list of opcodes] less than 100 is available.
681 ** Applications that define a custom xFileControl method should use opcodes
682 ** greater than 100 to avoid conflicts. VFS implementations should
683 ** return [SQLITE_NOTFOUND] for file control opcodes that they do not
686 ** The xSectorSize() method returns the sector size of the
687 ** device that underlies the file. The sector size is the
688 ** minimum write that can be performed without disturbing
689 ** other bytes in the file. The xDeviceCharacteristics()
690 ** method returns a bit vector describing behaviors of the
691 ** underlying device:
694 ** <li> [SQLITE_IOCAP_ATOMIC]
695 ** <li> [SQLITE_IOCAP_ATOMIC512]
696 ** <li> [SQLITE_IOCAP_ATOMIC1K]
697 ** <li> [SQLITE_IOCAP_ATOMIC2K]
698 ** <li> [SQLITE_IOCAP_ATOMIC4K]
699 ** <li> [SQLITE_IOCAP_ATOMIC8K]
700 ** <li> [SQLITE_IOCAP_ATOMIC16K]
701 ** <li> [SQLITE_IOCAP_ATOMIC32K]
702 ** <li> [SQLITE_IOCAP_ATOMIC64K]
703 ** <li> [SQLITE_IOCAP_SAFE_APPEND]
704 ** <li> [SQLITE_IOCAP_SEQUENTIAL]
707 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
708 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
709 ** mean that writes of blocks that are nnn bytes in size and
710 ** are aligned to an address which is an integer multiple of
711 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
712 ** that when data is appended to a file, the data is appended
713 ** first then the size of the file is extended, never the other
714 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
715 ** information is written to disk in the same order as calls
718 ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
719 ** in the unread portions of the buffer with zeros. A VFS that
720 ** fails to zero-fill short reads might seem to work. However,
721 ** failure to zero-fill short reads will eventually lead to
722 ** database corruption.
724 typedef struct sqlite3_io_methods sqlite3_io_methods;
725 struct sqlite3_io_methods {
727 int (*xClose)(sqlite3_file*);
728 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
729 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
730 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
731 int (*xSync)(sqlite3_file*, int flags);
732 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
733 int (*xLock)(sqlite3_file*, int);
734 int (*xUnlock)(sqlite3_file*, int);
735 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
736 int (*xFileControl)(sqlite3_file*, int op, void *pArg);
737 int (*xSectorSize)(sqlite3_file*);
738 int (*xDeviceCharacteristics)(sqlite3_file*);
739 /* Methods above are valid for version 1 */
740 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
741 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
742 void (*xShmBarrier)(sqlite3_file*);
743 int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
744 /* Methods above are valid for version 2 */
745 int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp);
746 int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p);
747 /* Methods above are valid for version 3 */
748 /* Additional methods may be added in future releases */
752 ** CAPI3REF: Standard File Control Opcodes
753 ** KEYWORDS: {file control opcodes} {file control opcode}
755 ** These integer constants are opcodes for the xFileControl method
756 ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
759 ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This
760 ** opcode causes the xFileControl method to write the current state of
761 ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
762 ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
763 ** into an integer that the pArg argument points to. This capability
764 ** is used during testing and only needs to be supported when SQLITE_TEST
767 ** <li>[[SQLITE_FCNTL_SIZE_HINT]]
768 ** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
769 ** layer a hint of how large the database file will grow to be during the
770 ** current transaction. This hint is not guaranteed to be accurate but it
771 ** is often close. The underlying VFS might choose to preallocate database
772 ** file space based on this hint in order to help writes to the database
775 ** <li>[[SQLITE_FCNTL_CHUNK_SIZE]]
776 ** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
777 ** extends and truncates the database file in chunks of a size specified
778 ** by the user. The fourth argument to [sqlite3_file_control()] should
779 ** point to an integer (type int) containing the new chunk-size to use
780 ** for the nominated database. Allocating database file space in large
781 ** chunks (say 1MB at a time), may reduce file-system fragmentation and
782 ** improve performance on some systems.
784 ** <li>[[SQLITE_FCNTL_FILE_POINTER]]
785 ** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
786 ** to the [sqlite3_file] object associated with a particular database
787 ** connection. See the [sqlite3_file_control()] documentation for
788 ** additional information.
790 ** <li>[[SQLITE_FCNTL_SYNC_OMITTED]]
793 ** <li>[[SQLITE_FCNTL_SYNC]]
794 ** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and
795 ** sent to the VFS immediately before the xSync method is invoked on a
796 ** database file descriptor. Or, if the xSync method is not invoked
797 ** because the user has configured SQLite with
798 ** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place
799 ** of the xSync method. In most cases, the pointer argument passed with
800 ** this file-control is NULL. However, if the database file is being synced
801 ** as part of a multi-database commit, the argument points to a nul-terminated
802 ** string containing the transactions master-journal file name. VFSes that
803 ** do not need this signal should silently ignore this opcode. Applications
804 ** should not call [sqlite3_file_control()] with this opcode as doing so may
805 ** disrupt the operation of the specialized VFSes that do require it.
807 ** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]]
808 ** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite
809 ** and sent to the VFS after a transaction has been committed immediately
810 ** but before the database is unlocked. VFSes that do not need this signal
811 ** should silently ignore this opcode. Applications should not call
812 ** [sqlite3_file_control()] with this opcode as doing so may disrupt the
813 ** operation of the specialized VFSes that do require it.
815 ** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]]
816 ** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
817 ** retry counts and intervals for certain disk I/O operations for the
818 ** windows [VFS] in order to provide robustness in the presence of
819 ** anti-virus programs. By default, the windows VFS will retry file read,
820 ** file write, and file delete operations up to 10 times, with a delay
821 ** of 25 milliseconds before the first retry and with the delay increasing
822 ** by an additional 25 milliseconds with each subsequent retry. This
823 ** opcode allows these two values (10 retries and 25 milliseconds of delay)
824 ** to be adjusted. The values are changed for all database connections
825 ** within the same process. The argument is a pointer to an array of two
826 ** integers where the first integer i the new retry count and the second
827 ** integer is the delay. If either integer is negative, then the setting
828 ** is not changed but instead the prior value of that setting is written
829 ** into the array entry, allowing the current retry settings to be
830 ** interrogated. The zDbName parameter is ignored.
832 ** <li>[[SQLITE_FCNTL_PERSIST_WAL]]
833 ** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
834 ** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary
835 ** write ahead log and shared memory files used for transaction control
836 ** are automatically deleted when the latest connection to the database
837 ** closes. Setting persistent WAL mode causes those files to persist after
838 ** close. Persisting the files is useful when other processes that do not
839 ** have write permission on the directory containing the database file want
840 ** to read the database file, as the WAL and shared memory files must exist
841 ** in order for the database to be readable. The fourth parameter to
842 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
843 ** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
844 ** WAL mode. If the integer is -1, then it is overwritten with the current
845 ** WAL persistence setting.
847 ** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]]
848 ** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
849 ** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting
850 ** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
851 ** xDeviceCharacteristics methods. The fourth parameter to
852 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
853 ** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
854 ** mode. If the integer is -1, then it is overwritten with the current
855 ** zero-damage mode setting.
857 ** <li>[[SQLITE_FCNTL_OVERWRITE]]
858 ** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
859 ** a write transaction to indicate that, unless it is rolled back for some
860 ** reason, the entire database file will be overwritten by the current
861 ** transaction. This is used by VACUUM operations.
863 ** <li>[[SQLITE_FCNTL_VFSNAME]]
864 ** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
865 ** all [VFSes] in the VFS stack. The names are of all VFS shims and the
866 ** final bottom-level VFS are written into memory obtained from
867 ** [sqlite3_malloc()] and the result is stored in the char* variable
868 ** that the fourth parameter of [sqlite3_file_control()] points to.
869 ** The caller is responsible for freeing the memory when done. As with
870 ** all file-control actions, there is no guarantee that this will actually
871 ** do anything. Callers should initialize the char* variable to a NULL
872 ** pointer in case this file-control is not implemented. This file-control
873 ** is intended for diagnostic use only.
875 ** <li>[[SQLITE_FCNTL_PRAGMA]]
876 ** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA]
877 ** file control is sent to the open [sqlite3_file] object corresponding
878 ** to the database file to which the pragma statement refers. ^The argument
879 ** to the [SQLITE_FCNTL_PRAGMA] file control is an array of
880 ** pointers to strings (char**) in which the second element of the array
881 ** is the name of the pragma and the third element is the argument to the
882 ** pragma or NULL if the pragma has no argument. ^The handler for an
883 ** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element
884 ** of the char** argument point to a string obtained from [sqlite3_mprintf()]
885 ** or the equivalent and that string will become the result of the pragma or
886 ** the error message if the pragma fails. ^If the
887 ** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal
888 ** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA]
889 ** file control returns [SQLITE_OK], then the parser assumes that the
890 ** VFS has handled the PRAGMA itself and the parser generates a no-op
891 ** prepared statement. ^If the [SQLITE_FCNTL_PRAGMA] file control returns
892 ** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means
893 ** that the VFS encountered an error while handling the [PRAGMA] and the
894 ** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA]
895 ** file control occurs at the beginning of pragma statement analysis and so
896 ** it is able to override built-in [PRAGMA] statements.
898 ** <li>[[SQLITE_FCNTL_BUSYHANDLER]]
899 ** ^The [SQLITE_FCNTL_BUSYHANDLER]
900 ** file-control may be invoked by SQLite on the database file handle
901 ** shortly after it is opened in order to provide a custom VFS with access
902 ** to the connections busy-handler callback. The argument is of type (void **)
903 ** - an array of two (void *) values. The first (void *) actually points
904 ** to a function of type (int (*)(void *)). In order to invoke the connections
905 ** busy-handler, this function should be invoked with the second (void *) in
906 ** the array as the only argument. If it returns non-zero, then the operation
907 ** should be retried. If it returns zero, the custom VFS should abandon the
908 ** current operation.
910 ** <li>[[SQLITE_FCNTL_TEMPFILENAME]]
911 ** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control
912 ** to have SQLite generate a
913 ** temporary filename using the same algorithm that is followed to generate
914 ** temporary filenames for TEMP tables and other internal uses. The
915 ** argument should be a char** which will be filled with the filename
916 ** written into memory obtained from [sqlite3_malloc()]. The caller should
917 ** invoke [sqlite3_free()] on the result to avoid a memory leak.
919 ** <li>[[SQLITE_FCNTL_MMAP_SIZE]]
920 ** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the
921 ** maximum number of bytes that will be used for memory-mapped I/O.
922 ** The argument is a pointer to a value of type sqlite3_int64 that
923 ** is an advisory maximum number of bytes in the file to memory map. The
924 ** pointer is overwritten with the old value. The limit is not changed if
925 ** the value originally pointed to is negative, and so the current limit
926 ** can be queried by passing in a pointer to a negative number. This
927 ** file-control is used internally to implement [PRAGMA mmap_size].
929 ** <li>[[SQLITE_FCNTL_TRACE]]
930 ** The [SQLITE_FCNTL_TRACE] file control provides advisory information
931 ** to the VFS about what the higher layers of the SQLite stack are doing.
932 ** This file control is used by some VFS activity tracing [shims].
933 ** The argument is a zero-terminated string. Higher layers in the
934 ** SQLite stack may generate instances of this file control if
935 ** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled.
937 ** <li>[[SQLITE_FCNTL_HAS_MOVED]]
938 ** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a
939 ** pointer to an integer and it writes a boolean into that integer depending
940 ** on whether or not the file has been renamed, moved, or deleted since it
943 ** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]]
944 ** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This
945 ** opcode causes the xFileControl method to swap the file handle with the one
946 ** pointed to by the pArg argument. This capability is used during testing
947 ** and only needs to be supported when SQLITE_TEST is defined.
951 #define SQLITE_FCNTL_LOCKSTATE 1
952 #define SQLITE_GET_LOCKPROXYFILE 2
953 #define SQLITE_SET_LOCKPROXYFILE 3
954 #define SQLITE_LAST_ERRNO 4
955 #define SQLITE_FCNTL_SIZE_HINT 5
956 #define SQLITE_FCNTL_CHUNK_SIZE 6
957 #define SQLITE_FCNTL_FILE_POINTER 7
958 #define SQLITE_FCNTL_SYNC_OMITTED 8
959 #define SQLITE_FCNTL_WIN32_AV_RETRY 9
960 #define SQLITE_FCNTL_PERSIST_WAL 10
961 #define SQLITE_FCNTL_OVERWRITE 11
962 #define SQLITE_FCNTL_VFSNAME 12
963 #define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13
964 #define SQLITE_FCNTL_PRAGMA 14
965 #define SQLITE_FCNTL_BUSYHANDLER 15
966 #define SQLITE_FCNTL_TEMPFILENAME 16
967 #define SQLITE_FCNTL_MMAP_SIZE 18
968 #define SQLITE_FCNTL_TRACE 19
969 #define SQLITE_FCNTL_HAS_MOVED 20
970 #define SQLITE_FCNTL_SYNC 21
971 #define SQLITE_FCNTL_COMMIT_PHASETWO 22
972 #define SQLITE_FCNTL_WIN32_SET_HANDLE 23
975 ** CAPI3REF: Mutex Handle
977 ** The mutex module within SQLite defines [sqlite3_mutex] to be an
978 ** abstract type for a mutex object. The SQLite core never looks
979 ** at the internal representation of an [sqlite3_mutex]. It only
980 ** deals with pointers to the [sqlite3_mutex] object.
982 ** Mutexes are created using [sqlite3_mutex_alloc()].
984 typedef struct sqlite3_mutex sqlite3_mutex;
987 ** CAPI3REF: OS Interface Object
989 ** An instance of the sqlite3_vfs object defines the interface between
990 ** the SQLite core and the underlying operating system. The "vfs"
991 ** in the name of the object stands for "virtual file system". See
992 ** the [VFS | VFS documentation] for further information.
994 ** The value of the iVersion field is initially 1 but may be larger in
995 ** future versions of SQLite. Additional fields may be appended to this
996 ** object when the iVersion value is increased. Note that the structure
997 ** of the sqlite3_vfs object changes in the transaction between
998 ** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not
1001 ** The szOsFile field is the size of the subclassed [sqlite3_file]
1002 ** structure used by this VFS. mxPathname is the maximum length of
1003 ** a pathname in this VFS.
1005 ** Registered sqlite3_vfs objects are kept on a linked list formed by
1006 ** the pNext pointer. The [sqlite3_vfs_register()]
1007 ** and [sqlite3_vfs_unregister()] interfaces manage this list
1008 ** in a thread-safe way. The [sqlite3_vfs_find()] interface
1009 ** searches the list. Neither the application code nor the VFS
1010 ** implementation should use the pNext pointer.
1012 ** The pNext field is the only field in the sqlite3_vfs
1013 ** structure that SQLite will ever modify. SQLite will only access
1014 ** or modify this field while holding a particular static mutex.
1015 ** The application should never modify anything within the sqlite3_vfs
1016 ** object once the object has been registered.
1018 ** The zName field holds the name of the VFS module. The name must
1019 ** be unique across all VFS modules.
1021 ** [[sqlite3_vfs.xOpen]]
1022 ** ^SQLite guarantees that the zFilename parameter to xOpen
1023 ** is either a NULL pointer or string obtained
1024 ** from xFullPathname() with an optional suffix added.
1025 ** ^If a suffix is added to the zFilename parameter, it will
1026 ** consist of a single "-" character followed by no more than
1027 ** 11 alphanumeric and/or "-" characters.
1028 ** ^SQLite further guarantees that
1029 ** the string will be valid and unchanged until xClose() is
1030 ** called. Because of the previous sentence,
1031 ** the [sqlite3_file] can safely store a pointer to the
1032 ** filename if it needs to remember the filename for some reason.
1033 ** If the zFilename parameter to xOpen is a NULL pointer then xOpen
1034 ** must invent its own temporary name for the file. ^Whenever the
1035 ** xFilename parameter is NULL it will also be the case that the
1036 ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
1038 ** The flags argument to xOpen() includes all bits set in
1039 ** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()]
1040 ** or [sqlite3_open16()] is used, then flags includes at least
1041 ** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE].
1042 ** If xOpen() opens a file read-only then it sets *pOutFlags to
1043 ** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set.
1045 ** ^(SQLite will also add one of the following flags to the xOpen()
1046 ** call, depending on the object being opened:
1049 ** <li> [SQLITE_OPEN_MAIN_DB]
1050 ** <li> [SQLITE_OPEN_MAIN_JOURNAL]
1051 ** <li> [SQLITE_OPEN_TEMP_DB]
1052 ** <li> [SQLITE_OPEN_TEMP_JOURNAL]
1053 ** <li> [SQLITE_OPEN_TRANSIENT_DB]
1054 ** <li> [SQLITE_OPEN_SUBJOURNAL]
1055 ** <li> [SQLITE_OPEN_MASTER_JOURNAL]
1056 ** <li> [SQLITE_OPEN_WAL]
1059 ** The file I/O implementation can use the object type flags to
1060 ** change the way it deals with files. For example, an application
1061 ** that does not care about crash recovery or rollback might make
1062 ** the open of a journal file a no-op. Writes to this journal would
1063 ** also be no-ops, and any attempt to read the journal would return
1064 ** SQLITE_IOERR. Or the implementation might recognize that a database
1065 ** file will be doing page-aligned sector reads and writes in a random
1066 ** order and set up its I/O subsystem accordingly.
1068 ** SQLite might also add one of the following flags to the xOpen method:
1071 ** <li> [SQLITE_OPEN_DELETEONCLOSE]
1072 ** <li> [SQLITE_OPEN_EXCLUSIVE]
1075 ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
1076 ** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE]
1077 ** will be set for TEMP databases and their journals, transient
1078 ** databases, and subjournals.
1080 ** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
1081 ** with the [SQLITE_OPEN_CREATE] flag, which are both directly
1082 ** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
1083 ** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
1084 ** SQLITE_OPEN_CREATE, is used to indicate that file should always
1085 ** be created, and that it is an error if it already exists.
1086 ** It is <i>not</i> used to indicate the file should be opened
1087 ** for exclusive access.
1089 ** ^At least szOsFile bytes of memory are allocated by SQLite
1090 ** to hold the [sqlite3_file] structure passed as the third
1091 ** argument to xOpen. The xOpen method does not have to
1092 ** allocate the structure; it should just fill it in. Note that
1093 ** the xOpen method must set the sqlite3_file.pMethods to either
1094 ** a valid [sqlite3_io_methods] object or to NULL. xOpen must do
1095 ** this even if the open fails. SQLite expects that the sqlite3_file.pMethods
1096 ** element will be valid after xOpen returns regardless of the success
1097 ** or failure of the xOpen call.
1099 ** [[sqlite3_vfs.xAccess]]
1100 ** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
1101 ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
1102 ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
1103 ** to test whether a file is at least readable. The file can be a
1106 ** ^SQLite will always allocate at least mxPathname+1 bytes for the
1107 ** output buffer xFullPathname. The exact size of the output buffer
1108 ** is also passed as a parameter to both methods. If the output buffer
1109 ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
1110 ** handled as a fatal error by SQLite, vfs implementations should endeavor
1111 ** to prevent this by setting mxPathname to a sufficiently large value.
1113 ** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
1114 ** interfaces are not strictly a part of the filesystem, but they are
1115 ** included in the VFS structure for completeness.
1116 ** The xRandomness() function attempts to return nBytes bytes
1117 ** of good-quality randomness into zOut. The return value is
1118 ** the actual number of bytes of randomness obtained.
1119 ** The xSleep() method causes the calling thread to sleep for at
1120 ** least the number of microseconds given. ^The xCurrentTime()
1121 ** method returns a Julian Day Number for the current date and time as
1122 ** a floating point value.
1123 ** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
1124 ** Day Number multiplied by 86400000 (the number of milliseconds in
1126 ** ^SQLite will use the xCurrentTimeInt64() method to get the current
1127 ** date and time if that method is available (if iVersion is 2 or
1128 ** greater and the function pointer is not NULL) and will fall back
1129 ** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
1131 ** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
1132 ** are not used by the SQLite core. These optional interfaces are provided
1133 ** by some VFSes to facilitate testing of the VFS code. By overriding
1134 ** system calls with functions under its control, a test program can
1135 ** simulate faults and error conditions that would otherwise be difficult
1136 ** or impossible to induce. The set of system calls that can be overridden
1137 ** varies from one VFS to another, and from one version of the same VFS to the
1138 ** next. Applications that use these interfaces must be prepared for any
1139 ** or all of these interfaces to be NULL or for their behavior to change
1140 ** from one release to the next. Applications must not attempt to access
1141 ** any of these methods if the iVersion of the VFS is less than 3.
1143 typedef struct sqlite3_vfs sqlite3_vfs;
1144 typedef void (*sqlite3_syscall_ptr)(void);
1145 struct sqlite3_vfs {
1146 int iVersion; /* Structure version number (currently 3) */
1147 int szOsFile; /* Size of subclassed sqlite3_file */
1148 int mxPathname; /* Maximum file pathname length */
1149 sqlite3_vfs *pNext; /* Next registered VFS */
1150 const char *zName; /* Name of this virtual file system */
1151 void *pAppData; /* Pointer to application-specific data */
1152 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
1153 int flags, int *pOutFlags);
1154 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
1155 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
1156 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
1157 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
1158 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
1159 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
1160 void (*xDlClose)(sqlite3_vfs*, void*);
1161 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
1162 int (*xSleep)(sqlite3_vfs*, int microseconds);
1163 int (*xCurrentTime)(sqlite3_vfs*, double*);
1164 int (*xGetLastError)(sqlite3_vfs*, int, char *);
1166 ** The methods above are in version 1 of the sqlite_vfs object
1167 ** definition. Those that follow are added in version 2 or later
1169 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
1171 ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
1172 ** Those below are for version 3 and greater.
1174 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
1175 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
1176 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
1178 ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
1179 ** New fields may be appended in figure versions. The iVersion
1180 ** value will increment whenever this happens.
1185 ** CAPI3REF: Flags for the xAccess VFS method
1187 ** These integer constants can be used as the third parameter to
1188 ** the xAccess method of an [sqlite3_vfs] object. They determine
1189 ** what kind of permissions the xAccess method is looking for.
1190 ** With SQLITE_ACCESS_EXISTS, the xAccess method
1191 ** simply checks whether the file exists.
1192 ** With SQLITE_ACCESS_READWRITE, the xAccess method
1193 ** checks whether the named directory is both readable and writable
1194 ** (in other words, if files can be added, removed, and renamed within
1196 ** The SQLITE_ACCESS_READWRITE constant is currently used only by the
1197 ** [temp_store_directory pragma], though this could change in a future
1198 ** release of SQLite.
1199 ** With SQLITE_ACCESS_READ, the xAccess method
1200 ** checks whether the file is readable. The SQLITE_ACCESS_READ constant is
1201 ** currently unused, though it might be used in a future release of
1204 #define SQLITE_ACCESS_EXISTS 0
1205 #define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */
1206 #define SQLITE_ACCESS_READ 2 /* Unused */
1209 ** CAPI3REF: Flags for the xShmLock VFS method
1211 ** These integer constants define the various locking operations
1212 ** allowed by the xShmLock method of [sqlite3_io_methods]. The
1213 ** following are the only legal combinations of flags to the
1217 ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
1218 ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
1219 ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
1220 ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
1223 ** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
1224 ** was given on the corresponding lock.
1226 ** The xShmLock method can transition between unlocked and SHARED or
1227 ** between unlocked and EXCLUSIVE. It cannot transition between SHARED
1230 #define SQLITE_SHM_UNLOCK 1
1231 #define SQLITE_SHM_LOCK 2
1232 #define SQLITE_SHM_SHARED 4
1233 #define SQLITE_SHM_EXCLUSIVE 8
1236 ** CAPI3REF: Maximum xShmLock index
1238 ** The xShmLock method on [sqlite3_io_methods] may use values
1239 ** between 0 and this upper bound as its "offset" argument.
1240 ** The SQLite core will never attempt to acquire or release a
1241 ** lock outside of this range
1243 #define SQLITE_SHM_NLOCK 8
1247 ** CAPI3REF: Initialize The SQLite Library
1249 ** ^The sqlite3_initialize() routine initializes the
1250 ** SQLite library. ^The sqlite3_shutdown() routine
1251 ** deallocates any resources that were allocated by sqlite3_initialize().
1252 ** These routines are designed to aid in process initialization and
1253 ** shutdown on embedded systems. Workstation applications using
1254 ** SQLite normally do not need to invoke either of these routines.
1256 ** A call to sqlite3_initialize() is an "effective" call if it is
1257 ** the first time sqlite3_initialize() is invoked during the lifetime of
1258 ** the process, or if it is the first time sqlite3_initialize() is invoked
1259 ** following a call to sqlite3_shutdown(). ^(Only an effective call
1260 ** of sqlite3_initialize() does any initialization. All other calls
1261 ** are harmless no-ops.)^
1263 ** A call to sqlite3_shutdown() is an "effective" call if it is the first
1264 ** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only
1265 ** an effective call to sqlite3_shutdown() does any deinitialization.
1266 ** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
1268 ** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
1269 ** is not. The sqlite3_shutdown() interface must only be called from a
1270 ** single thread. All open [database connections] must be closed and all
1271 ** other SQLite resources must be deallocated prior to invoking
1272 ** sqlite3_shutdown().
1274 ** Among other things, ^sqlite3_initialize() will invoke
1275 ** sqlite3_os_init(). Similarly, ^sqlite3_shutdown()
1276 ** will invoke sqlite3_os_end().
1278 ** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
1279 ** ^If for some reason, sqlite3_initialize() is unable to initialize
1280 ** the library (perhaps it is unable to allocate a needed resource such
1281 ** as a mutex) it returns an [error code] other than [SQLITE_OK].
1283 ** ^The sqlite3_initialize() routine is called internally by many other
1284 ** SQLite interfaces so that an application usually does not need to
1285 ** invoke sqlite3_initialize() directly. For example, [sqlite3_open()]
1286 ** calls sqlite3_initialize() so the SQLite library will be automatically
1287 ** initialized when [sqlite3_open()] is called if it has not be initialized
1288 ** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
1289 ** compile-time option, then the automatic calls to sqlite3_initialize()
1290 ** are omitted and the application must call sqlite3_initialize() directly
1291 ** prior to using any other SQLite interface. For maximum portability,
1292 ** it is recommended that applications always invoke sqlite3_initialize()
1293 ** directly prior to using any other SQLite interface. Future releases
1294 ** of SQLite may require this. In other words, the behavior exhibited
1295 ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
1296 ** default behavior in some future release of SQLite.
1298 ** The sqlite3_os_init() routine does operating-system specific
1299 ** initialization of the SQLite library. The sqlite3_os_end()
1300 ** routine undoes the effect of sqlite3_os_init(). Typical tasks
1301 ** performed by these routines include allocation or deallocation
1302 ** of static resources, initialization of global variables,
1303 ** setting up a default [sqlite3_vfs] module, or setting up
1304 ** a default configuration using [sqlite3_config()].
1306 ** The application should never invoke either sqlite3_os_init()
1307 ** or sqlite3_os_end() directly. The application should only invoke
1308 ** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init()
1309 ** interface is called automatically by sqlite3_initialize() and
1310 ** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate
1311 ** implementations for sqlite3_os_init() and sqlite3_os_end()
1312 ** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
1313 ** When [custom builds | built for other platforms]
1314 ** (using the [SQLITE_OS_OTHER=1] compile-time
1315 ** option) the application must supply a suitable implementation for
1316 ** sqlite3_os_init() and sqlite3_os_end(). An application-supplied
1317 ** implementation of sqlite3_os_init() or sqlite3_os_end()
1318 ** must return [SQLITE_OK] on success and some other [error code] upon
1321 SQLITE_API int sqlite3_initialize(void);
1322 SQLITE_API int sqlite3_shutdown(void);
1323 SQLITE_API int sqlite3_os_init(void);
1324 SQLITE_API int sqlite3_os_end(void);
1327 ** CAPI3REF: Configuring The SQLite Library
1329 ** The sqlite3_config() interface is used to make global configuration
1330 ** changes to SQLite in order to tune SQLite to the specific needs of
1331 ** the application. The default configuration is recommended for most
1332 ** applications and so this routine is usually not necessary. It is
1333 ** provided to support rare applications with unusual needs.
1335 ** The sqlite3_config() interface is not threadsafe. The application
1336 ** must insure that no other SQLite interfaces are invoked by other
1337 ** threads while sqlite3_config() is running. Furthermore, sqlite3_config()
1338 ** may only be invoked prior to library initialization using
1339 ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
1340 ** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
1341 ** [sqlite3_shutdown()] then it will return SQLITE_MISUSE.
1342 ** Note, however, that ^sqlite3_config() can be called as part of the
1343 ** implementation of an application-defined [sqlite3_os_init()].
1345 ** The first argument to sqlite3_config() is an integer
1346 ** [configuration option] that determines
1347 ** what property of SQLite is to be configured. Subsequent arguments
1348 ** vary depending on the [configuration option]
1349 ** in the first argument.
1351 ** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
1352 ** ^If the option is unknown or SQLite is unable to set the option
1353 ** then this routine returns a non-zero [error code].
1355 SQLITE_API int sqlite3_config(int, ...);
1358 ** CAPI3REF: Configure database connections
1360 ** The sqlite3_db_config() interface is used to make configuration
1361 ** changes to a [database connection]. The interface is similar to
1362 ** [sqlite3_config()] except that the changes apply to a single
1363 ** [database connection] (specified in the first argument).
1365 ** The second argument to sqlite3_db_config(D,V,...) is the
1366 ** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code
1367 ** that indicates what aspect of the [database connection] is being configured.
1368 ** Subsequent arguments vary depending on the configuration verb.
1370 ** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
1371 ** the call is considered successful.
1373 SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...);
1376 ** CAPI3REF: Memory Allocation Routines
1378 ** An instance of this object defines the interface between SQLite
1379 ** and low-level memory allocation routines.
1381 ** This object is used in only one place in the SQLite interface.
1382 ** A pointer to an instance of this object is the argument to
1383 ** [sqlite3_config()] when the configuration option is
1384 ** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].
1385 ** By creating an instance of this object
1386 ** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
1387 ** during configuration, an application can specify an alternative
1388 ** memory allocation subsystem for SQLite to use for all of its
1389 ** dynamic memory needs.
1391 ** Note that SQLite comes with several [built-in memory allocators]
1392 ** that are perfectly adequate for the overwhelming majority of applications
1393 ** and that this object is only useful to a tiny minority of applications
1394 ** with specialized memory allocation requirements. This object is
1395 ** also used during testing of SQLite in order to specify an alternative
1396 ** memory allocator that simulates memory out-of-memory conditions in
1397 ** order to verify that SQLite recovers gracefully from such
1400 ** The xMalloc, xRealloc, and xFree methods must work like the
1401 ** malloc(), realloc() and free() functions from the standard C library.
1402 ** ^SQLite guarantees that the second argument to
1403 ** xRealloc is always a value returned by a prior call to xRoundup.
1405 ** xSize should return the allocated size of a memory allocation
1406 ** previously obtained from xMalloc or xRealloc. The allocated size
1407 ** is always at least as big as the requested size but may be larger.
1409 ** The xRoundup method returns what would be the allocated size of
1410 ** a memory allocation given a particular requested size. Most memory
1411 ** allocators round up memory allocations at least to the next multiple
1412 ** of 8. Some allocators round up to a larger multiple or to a power of 2.
1413 ** Every memory allocation request coming in through [sqlite3_malloc()]
1414 ** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0,
1415 ** that causes the corresponding memory allocation to fail.
1417 ** The xInit method initializes the memory allocator. For example,
1418 ** it might allocate any require mutexes or initialize internal data
1419 ** structures. The xShutdown method is invoked (indirectly) by
1420 ** [sqlite3_shutdown()] and should deallocate any resources acquired
1421 ** by xInit. The pAppData pointer is used as the only parameter to
1422 ** xInit and xShutdown.
1424 ** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes
1425 ** the xInit method, so the xInit method need not be threadsafe. The
1426 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
1427 ** not need to be threadsafe either. For all other methods, SQLite
1428 ** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
1429 ** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
1430 ** it is by default) and so the methods are automatically serialized.
1431 ** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
1432 ** methods must be threadsafe or else make their own arrangements for
1435 ** SQLite will never invoke xInit() more than once without an intervening
1436 ** call to xShutdown().
1438 typedef struct sqlite3_mem_methods sqlite3_mem_methods;
1439 struct sqlite3_mem_methods {
1440 void *(*xMalloc)(int); /* Memory allocation function */
1441 void (*xFree)(void*); /* Free a prior allocation */
1442 void *(*xRealloc)(void*,int); /* Resize an allocation */
1443 int (*xSize)(void*); /* Return the size of an allocation */
1444 int (*xRoundup)(int); /* Round up request size to allocation size */
1445 int (*xInit)(void*); /* Initialize the memory allocator */
1446 void (*xShutdown)(void*); /* Deinitialize the memory allocator */
1447 void *pAppData; /* Argument to xInit() and xShutdown() */
1451 ** CAPI3REF: Configuration Options
1452 ** KEYWORDS: {configuration option}
1454 ** These constants are the available integer configuration options that
1455 ** can be passed as the first argument to the [sqlite3_config()] interface.
1457 ** New configuration options may be added in future releases of SQLite.
1458 ** Existing configuration options might be discontinued. Applications
1459 ** should check the return code from [sqlite3_config()] to make sure that
1460 ** the call worked. The [sqlite3_config()] interface will return a
1461 ** non-zero [error code] if a discontinued or unsupported configuration option
1465 ** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
1466 ** <dd>There are no arguments to this option. ^This option sets the
1467 ** [threading mode] to Single-thread. In other words, it disables
1468 ** all mutexing and puts SQLite into a mode where it can only be used
1469 ** by a single thread. ^If SQLite is compiled with
1470 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1471 ** it is not possible to change the [threading mode] from its default
1472 ** value of Single-thread and so [sqlite3_config()] will return
1473 ** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
1474 ** configuration option.</dd>
1476 ** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt>
1477 ** <dd>There are no arguments to this option. ^This option sets the
1478 ** [threading mode] to Multi-thread. In other words, it disables
1479 ** mutexing on [database connection] and [prepared statement] objects.
1480 ** The application is responsible for serializing access to
1481 ** [database connections] and [prepared statements]. But other mutexes
1482 ** are enabled so that SQLite will be safe to use in a multi-threaded
1483 ** environment as long as no two threads attempt to use the same
1484 ** [database connection] at the same time. ^If SQLite is compiled with
1485 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1486 ** it is not possible to set the Multi-thread [threading mode] and
1487 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1488 ** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
1490 ** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt>
1491 ** <dd>There are no arguments to this option. ^This option sets the
1492 ** [threading mode] to Serialized. In other words, this option enables
1493 ** all mutexes including the recursive
1494 ** mutexes on [database connection] and [prepared statement] objects.
1495 ** In this mode (which is the default when SQLite is compiled with
1496 ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
1497 ** to [database connections] and [prepared statements] so that the
1498 ** application is free to use the same [database connection] or the
1499 ** same [prepared statement] in different threads at the same time.
1500 ** ^If SQLite is compiled with
1501 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1502 ** it is not possible to set the Serialized [threading mode] and
1503 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1504 ** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
1506 ** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt>
1507 ** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is
1508 ** a pointer to an instance of the [sqlite3_mem_methods] structure.
1509 ** The argument specifies
1510 ** alternative low-level memory allocation routines to be used in place of
1511 ** the memory allocation routines built into SQLite.)^ ^SQLite makes
1512 ** its own private copy of the content of the [sqlite3_mem_methods] structure
1513 ** before the [sqlite3_config()] call returns.</dd>
1515 ** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt>
1516 ** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which
1517 ** is a pointer to an instance of the [sqlite3_mem_methods] structure.
1518 ** The [sqlite3_mem_methods]
1519 ** structure is filled with the currently defined memory allocation routines.)^
1520 ** This option can be used to overload the default memory allocation
1521 ** routines with a wrapper that simulations memory allocation failure or
1522 ** tracks memory usage, for example. </dd>
1524 ** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt>
1525 ** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int,
1526 ** interpreted as a boolean, which enables or disables the collection of
1527 ** memory allocation statistics. ^(When memory allocation statistics are
1528 ** disabled, the following SQLite interfaces become non-operational:
1530 ** <li> [sqlite3_memory_used()]
1531 ** <li> [sqlite3_memory_highwater()]
1532 ** <li> [sqlite3_soft_heap_limit64()]
1533 ** <li> [sqlite3_status()]
1535 ** ^Memory allocation statistics are enabled by default unless SQLite is
1536 ** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
1537 ** allocation statistics are disabled by default.
1540 ** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt>
1541 ** <dd> ^The SQLITE_CONFIG_SCRATCH option specifies a static memory buffer
1542 ** that SQLite can use for scratch memory. ^(There are three arguments
1543 ** to SQLITE_CONFIG_SCRATCH: A pointer an 8-byte
1544 ** aligned memory buffer from which the scratch allocations will be
1545 ** drawn, the size of each scratch allocation (sz),
1546 ** and the maximum number of scratch allocations (N).)^
1547 ** The first argument must be a pointer to an 8-byte aligned buffer
1548 ** of at least sz*N bytes of memory.
1549 ** ^SQLite will not use more than one scratch buffers per thread.
1550 ** ^SQLite will never request a scratch buffer that is more than 6
1551 ** times the database page size.
1552 ** ^If SQLite needs needs additional
1553 ** scratch memory beyond what is provided by this configuration option, then
1554 ** [sqlite3_malloc()] will be used to obtain the memory needed.<p>
1555 ** ^When the application provides any amount of scratch memory using
1556 ** SQLITE_CONFIG_SCRATCH, SQLite avoids unnecessary large
1557 ** [sqlite3_malloc|heap allocations].
1558 ** This can help [Robson proof|prevent memory allocation failures] due to heap
1559 ** fragmentation in low-memory embedded systems.
1562 ** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>
1563 ** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a static memory buffer
1564 ** that SQLite can use for the database page cache with the default page
1565 ** cache implementation.
1566 ** This configuration should not be used if an application-define page
1567 ** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2]
1568 ** configuration option.
1569 ** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to
1571 ** memory, the size of each page buffer (sz), and the number of pages (N).
1572 ** The sz argument should be the size of the largest database page
1573 ** (a power of two between 512 and 65536) plus some extra bytes for each
1574 ** page header. ^The number of extra bytes needed by the page header
1575 ** can be determined using the [SQLITE_CONFIG_PCACHE_HDRSZ] option
1576 ** to [sqlite3_config()].
1577 ** ^It is harmless, apart from the wasted memory,
1578 ** for the sz parameter to be larger than necessary. The first
1579 ** argument should pointer to an 8-byte aligned block of memory that
1580 ** is at least sz*N bytes of memory, otherwise subsequent behavior is
1582 ** ^SQLite will use the memory provided by the first argument to satisfy its
1583 ** memory needs for the first N pages that it adds to cache. ^If additional
1584 ** page cache memory is needed beyond what is provided by this option, then
1585 ** SQLite goes to [sqlite3_malloc()] for the additional storage space.</dd>
1587 ** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt>
1588 ** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer
1589 ** that SQLite will use for all of its dynamic memory allocation needs
1590 ** beyond those provided for by [SQLITE_CONFIG_SCRATCH] and
1591 ** [SQLITE_CONFIG_PAGECACHE].
1592 ** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled
1593 ** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns
1594 ** [SQLITE_ERROR] if invoked otherwise.
1595 ** ^There are three arguments to SQLITE_CONFIG_HEAP:
1596 ** An 8-byte aligned pointer to the memory,
1597 ** the number of bytes in the memory buffer, and the minimum allocation size.
1598 ** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
1599 ** to using its default memory allocator (the system malloc() implementation),
1600 ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the
1601 ** memory pointer is not NULL then the alternative memory
1602 ** allocator is engaged to handle all of SQLites memory allocation needs.
1603 ** The first pointer (the memory pointer) must be aligned to an 8-byte
1604 ** boundary or subsequent behavior of SQLite will be undefined.
1605 ** The minimum allocation size is capped at 2**12. Reasonable values
1606 ** for the minimum allocation size are 2**5 through 2**8.</dd>
1608 ** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt>
1609 ** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a
1610 ** pointer to an instance of the [sqlite3_mutex_methods] structure.
1611 ** The argument specifies alternative low-level mutex routines to be used
1612 ** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of
1613 ** the content of the [sqlite3_mutex_methods] structure before the call to
1614 ** [sqlite3_config()] returns. ^If SQLite is compiled with
1615 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1616 ** the entire mutexing subsystem is omitted from the build and hence calls to
1617 ** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
1618 ** return [SQLITE_ERROR].</dd>
1620 ** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt>
1621 ** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which
1622 ** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The
1623 ** [sqlite3_mutex_methods]
1624 ** structure is filled with the currently defined mutex routines.)^
1625 ** This option can be used to overload the default mutex allocation
1626 ** routines with a wrapper used to track mutex usage for performance
1627 ** profiling or testing, for example. ^If SQLite is compiled with
1628 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1629 ** the entire mutexing subsystem is omitted from the build and hence calls to
1630 ** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
1631 ** return [SQLITE_ERROR].</dd>
1633 ** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt>
1634 ** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine
1635 ** the default size of lookaside memory on each [database connection].
1636 ** The first argument is the
1637 ** size of each lookaside buffer slot and the second is the number of
1638 ** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE
1639 ** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
1640 ** option to [sqlite3_db_config()] can be used to change the lookaside
1641 ** configuration on individual connections.)^ </dd>
1643 ** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt>
1644 ** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is
1645 ** a pointer to an [sqlite3_pcache_methods2] object. This object specifies
1646 ** the interface to a custom page cache implementation.)^
1647 ** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd>
1649 ** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt>
1650 ** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which
1651 ** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of
1652 ** the current page cache implementation into that object.)^ </dd>
1654 ** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>
1655 ** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite
1656 ** global [error log].
1657 ** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
1658 ** function with a call signature of void(*)(void*,int,const char*),
1659 ** and a pointer to void. ^If the function pointer is not NULL, it is
1660 ** invoked by [sqlite3_log()] to process each logging event. ^If the
1661 ** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
1662 ** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
1663 ** passed through as the first parameter to the application-defined logger
1664 ** function whenever that function is invoked. ^The second parameter to
1665 ** the logger function is a copy of the first parameter to the corresponding
1666 ** [sqlite3_log()] call and is intended to be a [result code] or an
1667 ** [extended result code]. ^The third parameter passed to the logger is
1668 ** log message after formatting via [sqlite3_snprintf()].
1669 ** The SQLite logging interface is not reentrant; the logger function
1670 ** supplied by the application must not invoke any SQLite interface.
1671 ** In a multi-threaded application, the application-defined logger
1672 ** function must be threadsafe. </dd>
1674 ** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI
1675 ** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int.
1676 ** If non-zero, then URI handling is globally enabled. If the parameter is zero,
1677 ** then URI handling is globally disabled.)^ ^If URI handling is globally
1678 ** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()],
1679 ** [sqlite3_open16()] or
1680 ** specified as part of [ATTACH] commands are interpreted as URIs, regardless
1681 ** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
1682 ** connection is opened. ^If it is globally disabled, filenames are
1683 ** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
1684 ** database connection is opened. ^(By default, URI handling is globally
1685 ** disabled. The default value may be changed by compiling with the
1686 ** [SQLITE_USE_URI] symbol defined.)^
1688 ** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN
1689 ** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer
1690 ** argument which is interpreted as a boolean in order to enable or disable
1691 ** the use of covering indices for full table scans in the query optimizer.
1692 ** ^The default setting is determined
1693 ** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on"
1694 ** if that compile-time option is omitted.
1695 ** The ability to disable the use of covering indices for full table scans
1696 ** is because some incorrectly coded legacy applications might malfunction
1697 ** when the optimization is enabled. Providing the ability to
1698 ** disable the optimization allows the older, buggy application code to work
1699 ** without change even with newer versions of SQLite.
1701 ** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]]
1702 ** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE
1703 ** <dd> These options are obsolete and should not be used by new code.
1704 ** They are retained for backwards compatibility but are now no-ops.
1707 ** [[SQLITE_CONFIG_SQLLOG]]
1708 ** <dt>SQLITE_CONFIG_SQLLOG
1709 ** <dd>This option is only available if sqlite is compiled with the
1710 ** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should
1711 ** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int).
1712 ** The second should be of type (void*). The callback is invoked by the library
1713 ** in three separate circumstances, identified by the value passed as the
1714 ** fourth parameter. If the fourth parameter is 0, then the database connection
1715 ** passed as the second argument has just been opened. The third argument
1716 ** points to a buffer containing the name of the main database file. If the
1717 ** fourth parameter is 1, then the SQL statement that the third parameter
1718 ** points to has just been executed. Or, if the fourth parameter is 2, then
1719 ** the connection being passed as the second parameter is being closed. The
1720 ** third parameter is passed NULL In this case. An example of using this
1721 ** configuration option can be seen in the "test_sqllog.c" source file in
1722 ** the canonical SQLite source tree.</dd>
1724 ** [[SQLITE_CONFIG_MMAP_SIZE]]
1725 ** <dt>SQLITE_CONFIG_MMAP_SIZE
1726 ** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values
1727 ** that are the default mmap size limit (the default setting for
1728 ** [PRAGMA mmap_size]) and the maximum allowed mmap size limit.
1729 ** ^The default setting can be overridden by each database connection using
1730 ** either the [PRAGMA mmap_size] command, or by using the
1731 ** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size
1732 ** will be silently truncated if necessary so that it does not exceed the
1733 ** compile-time maximum mmap size set by the
1734 ** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^
1735 ** ^If either argument to this option is negative, then that argument is
1736 ** changed to its compile-time default.
1738 ** [[SQLITE_CONFIG_WIN32_HEAPSIZE]]
1739 ** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE
1740 ** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is
1741 ** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro
1742 ** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value
1743 ** that specifies the maximum size of the created heap.
1746 ** [[SQLITE_CONFIG_PCACHE_HDRSZ]]
1747 ** <dt>SQLITE_CONFIG_PCACHE_HDRSZ
1748 ** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which
1749 ** is a pointer to an integer and writes into that integer the number of extra
1750 ** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE].
1751 ** The amount of extra space required can change depending on the compiler,
1752 ** target platform, and SQLite version.
1754 ** [[SQLITE_CONFIG_PMASZ]]
1755 ** <dt>SQLITE_CONFIG_PMASZ
1756 ** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which
1757 ** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded
1758 ** sorter to that integer. The default minimum PMA Size is set by the
1759 ** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched
1760 ** to help with sort operations when multithreaded sorting
1761 ** is enabled (using the [PRAGMA threads] command) and the amount of content
1762 ** to be sorted exceeds the page size times the minimum of the
1763 ** [PRAGMA cache_size] setting and this value.
1766 #define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */
1767 #define SQLITE_CONFIG_MULTITHREAD 2 /* nil */
1768 #define SQLITE_CONFIG_SERIALIZED 3 /* nil */
1769 #define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */
1770 #define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */
1771 #define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */
1772 #define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */
1773 #define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */
1774 #define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */
1775 #define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */
1776 #define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */
1777 /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */
1778 #define SQLITE_CONFIG_LOOKASIDE 13 /* int int */
1779 #define SQLITE_CONFIG_PCACHE 14 /* no-op */
1780 #define SQLITE_CONFIG_GETPCACHE 15 /* no-op */
1781 #define SQLITE_CONFIG_LOG 16 /* xFunc, void* */
1782 #define SQLITE_CONFIG_URI 17 /* int */
1783 #define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */
1784 #define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */
1785 #define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */
1786 #define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */
1787 #define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */
1788 #define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */
1789 #define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */
1790 #define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */
1793 ** CAPI3REF: Database Connection Configuration Options
1795 ** These constants are the available integer configuration options that
1796 ** can be passed as the second argument to the [sqlite3_db_config()] interface.
1798 ** New configuration options may be added in future releases of SQLite.
1799 ** Existing configuration options might be discontinued. Applications
1800 ** should check the return code from [sqlite3_db_config()] to make sure that
1801 ** the call worked. ^The [sqlite3_db_config()] interface will return a
1802 ** non-zero [error code] if a discontinued or unsupported configuration option
1806 ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
1807 ** <dd> ^This option takes three additional arguments that determine the
1808 ** [lookaside memory allocator] configuration for the [database connection].
1809 ** ^The first argument (the third parameter to [sqlite3_db_config()] is a
1810 ** pointer to a memory buffer to use for lookaside memory.
1811 ** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
1812 ** may be NULL in which case SQLite will allocate the
1813 ** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
1814 ** size of each lookaside buffer slot. ^The third argument is the number of
1815 ** slots. The size of the buffer in the first argument must be greater than
1816 ** or equal to the product of the second and third arguments. The buffer
1817 ** must be aligned to an 8-byte boundary. ^If the second argument to
1818 ** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
1819 ** rounded down to the next smaller multiple of 8. ^(The lookaside memory
1820 ** configuration for a database connection can only be changed when that
1821 ** connection is not currently using lookaside memory, or in other words
1822 ** when the "current value" returned by
1823 ** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero.
1824 ** Any attempt to change the lookaside memory configuration when lookaside
1825 ** memory is in use leaves the configuration unchanged and returns
1826 ** [SQLITE_BUSY].)^</dd>
1828 ** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
1829 ** <dd> ^This option is used to enable or disable the enforcement of
1830 ** [foreign key constraints]. There should be two additional arguments.
1831 ** The first argument is an integer which is 0 to disable FK enforcement,
1832 ** positive to enable FK enforcement or negative to leave FK enforcement
1833 ** unchanged. The second parameter is a pointer to an integer into which
1834 ** is written 0 or 1 to indicate whether FK enforcement is off or on
1835 ** following this call. The second parameter may be a NULL pointer, in
1836 ** which case the FK enforcement setting is not reported back. </dd>
1838 ** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
1839 ** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
1840 ** There should be two additional arguments.
1841 ** The first argument is an integer which is 0 to disable triggers,
1842 ** positive to enable triggers or negative to leave the setting unchanged.
1843 ** The second parameter is a pointer to an integer into which
1844 ** is written 0 or 1 to indicate whether triggers are disabled or enabled
1845 ** following this call. The second parameter may be a NULL pointer, in
1846 ** which case the trigger setting is not reported back. </dd>
1850 #define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */
1851 #define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */
1852 #define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */
1856 ** CAPI3REF: Enable Or Disable Extended Result Codes
1858 ** ^The sqlite3_extended_result_codes() routine enables or disables the
1859 ** [extended result codes] feature of SQLite. ^The extended result
1860 ** codes are disabled by default for historical compatibility.
1862 SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff);
1865 ** CAPI3REF: Last Insert Rowid
1867 ** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables)
1868 ** has a unique 64-bit signed
1869 ** integer key called the [ROWID | "rowid"]. ^The rowid is always available
1870 ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
1871 ** names are not also used by explicitly declared columns. ^If
1872 ** the table has a column of type [INTEGER PRIMARY KEY] then that column
1873 ** is another alias for the rowid.
1875 ** ^The sqlite3_last_insert_rowid(D) interface returns the [rowid] of the
1876 ** most recent successful [INSERT] into a rowid table or [virtual table]
1877 ** on database connection D.
1878 ** ^Inserts into [WITHOUT ROWID] tables are not recorded.
1879 ** ^If no successful [INSERT]s into rowid tables
1880 ** have ever occurred on the database connection D,
1881 ** then sqlite3_last_insert_rowid(D) returns zero.
1883 ** ^(If an [INSERT] occurs within a trigger or within a [virtual table]
1884 ** method, then this routine will return the [rowid] of the inserted
1885 ** row as long as the trigger or virtual table method is running.
1886 ** But once the trigger or virtual table method ends, the value returned
1887 ** by this routine reverts to what it was before the trigger or virtual
1888 ** table method began.)^
1890 ** ^An [INSERT] that fails due to a constraint violation is not a
1891 ** successful [INSERT] and does not change the value returned by this
1892 ** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
1893 ** and INSERT OR ABORT make no changes to the return value of this
1894 ** routine when their insertion fails. ^(When INSERT OR REPLACE
1895 ** encounters a constraint violation, it does not fail. The
1896 ** INSERT continues to completion after deleting rows that caused
1897 ** the constraint problem so INSERT OR REPLACE will always change
1898 ** the return value of this interface.)^
1900 ** ^For the purposes of this routine, an [INSERT] is considered to
1901 ** be successful even if it is subsequently rolled back.
1903 ** This function is accessible to SQL statements via the
1904 ** [last_insert_rowid() SQL function].
1906 ** If a separate thread performs a new [INSERT] on the same
1907 ** database connection while the [sqlite3_last_insert_rowid()]
1908 ** function is running and thus changes the last insert [rowid],
1909 ** then the value returned by [sqlite3_last_insert_rowid()] is
1910 ** unpredictable and might not equal either the old or the new
1911 ** last insert [rowid].
1913 SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
1916 ** CAPI3REF: Count The Number Of Rows Modified
1918 ** ^This function returns the number of rows modified, inserted or
1919 ** deleted by the most recently completed INSERT, UPDATE or DELETE
1920 ** statement on the database connection specified by the only parameter.
1921 ** ^Executing any other type of SQL statement does not modify the value
1922 ** returned by this function.
1924 ** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are
1925 ** considered - auxiliary changes caused by [CREATE TRIGGER | triggers],
1926 ** [foreign key actions] or [REPLACE] constraint resolution are not counted.
1928 ** Changes to a view that are intercepted by
1929 ** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value
1930 ** returned by sqlite3_changes() immediately after an INSERT, UPDATE or
1931 ** DELETE statement run on a view is always zero. Only changes made to real
1932 ** tables are counted.
1934 ** Things are more complicated if the sqlite3_changes() function is
1935 ** executed while a trigger program is running. This may happen if the
1936 ** program uses the [changes() SQL function], or if some other callback
1937 ** function invokes sqlite3_changes() directly. Essentially:
1940 ** <li> ^(Before entering a trigger program the value returned by
1941 ** sqlite3_changes() function is saved. After the trigger program
1942 ** has finished, the original value is restored.)^
1944 ** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE
1945 ** statement sets the value returned by sqlite3_changes()
1946 ** upon completion as normal. Of course, this value will not include
1947 ** any changes performed by sub-triggers, as the sqlite3_changes()
1948 ** value will be saved and restored after each sub-trigger has run.)^
1951 ** ^This means that if the changes() SQL function (or similar) is used
1952 ** by the first INSERT, UPDATE or DELETE statement within a trigger, it
1953 ** returns the value as set when the calling statement began executing.
1954 ** ^If it is used by the second or subsequent such statement within a trigger
1955 ** program, the value returned reflects the number of rows modified by the
1956 ** previous INSERT, UPDATE or DELETE statement within the same trigger.
1958 ** See also the [sqlite3_total_changes()] interface, the
1959 ** [count_changes pragma], and the [changes() SQL function].
1961 ** If a separate thread makes changes on the same database connection
1962 ** while [sqlite3_changes()] is running then the value returned
1963 ** is unpredictable and not meaningful.
1965 SQLITE_API int sqlite3_changes(sqlite3*);
1968 ** CAPI3REF: Total Number Of Rows Modified
1970 ** ^This function returns the total number of rows inserted, modified or
1971 ** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed
1972 ** since the database connection was opened, including those executed as
1973 ** part of trigger programs. ^Executing any other type of SQL statement
1974 ** does not affect the value returned by sqlite3_total_changes().
1976 ** ^Changes made as part of [foreign key actions] are included in the
1977 ** count, but those made as part of REPLACE constraint resolution are
1978 ** not. ^Changes to a view that are intercepted by INSTEAD OF triggers
1981 ** See also the [sqlite3_changes()] interface, the
1982 ** [count_changes pragma], and the [total_changes() SQL function].
1984 ** If a separate thread makes changes on the same database connection
1985 ** while [sqlite3_total_changes()] is running then the value
1986 ** returned is unpredictable and not meaningful.
1988 SQLITE_API int sqlite3_total_changes(sqlite3*);
1991 ** CAPI3REF: Interrupt A Long-Running Query
1993 ** ^This function causes any pending database operation to abort and
1994 ** return at its earliest opportunity. This routine is typically
1995 ** called in response to a user action such as pressing "Cancel"
1996 ** or Ctrl-C where the user wants a long query operation to halt
1999 ** ^It is safe to call this routine from a thread different from the
2000 ** thread that is currently running the database operation. But it
2001 ** is not safe to call this routine with a [database connection] that
2002 ** is closed or might close before sqlite3_interrupt() returns.
2004 ** ^If an SQL operation is very nearly finished at the time when
2005 ** sqlite3_interrupt() is called, then it might not have an opportunity
2006 ** to be interrupted and might continue to completion.
2008 ** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
2009 ** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
2010 ** that is inside an explicit transaction, then the entire transaction
2011 ** will be rolled back automatically.
2013 ** ^The sqlite3_interrupt(D) call is in effect until all currently running
2014 ** SQL statements on [database connection] D complete. ^Any new SQL statements
2015 ** that are started after the sqlite3_interrupt() call and before the
2016 ** running statements reaches zero are interrupted as if they had been
2017 ** running prior to the sqlite3_interrupt() call. ^New SQL statements
2018 ** that are started after the running statement count reaches zero are
2019 ** not effected by the sqlite3_interrupt().
2020 ** ^A call to sqlite3_interrupt(D) that occurs when there are no running
2021 ** SQL statements is a no-op and has no effect on SQL statements
2022 ** that are started after the sqlite3_interrupt() call returns.
2024 ** If the database connection closes while [sqlite3_interrupt()]
2025 ** is running then bad things will likely happen.
2027 SQLITE_API void sqlite3_interrupt(sqlite3*);
2030 ** CAPI3REF: Determine If An SQL Statement Is Complete
2032 ** These routines are useful during command-line input to determine if the
2033 ** currently entered text seems to form a complete SQL statement or
2034 ** if additional input is needed before sending the text into
2035 ** SQLite for parsing. ^These routines return 1 if the input string
2036 ** appears to be a complete SQL statement. ^A statement is judged to be
2037 ** complete if it ends with a semicolon token and is not a prefix of a
2038 ** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within
2039 ** string literals or quoted identifier names or comments are not
2040 ** independent tokens (they are part of the token in which they are
2041 ** embedded) and thus do not count as a statement terminator. ^Whitespace
2042 ** and comments that follow the final semicolon are ignored.
2044 ** ^These routines return 0 if the statement is incomplete. ^If a
2045 ** memory allocation fails, then SQLITE_NOMEM is returned.
2047 ** ^These routines do not parse the SQL statements thus
2048 ** will not detect syntactically incorrect SQL.
2050 ** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior
2051 ** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
2052 ** automatically by sqlite3_complete16(). If that initialization fails,
2053 ** then the return value from sqlite3_complete16() will be non-zero
2054 ** regardless of whether or not the input SQL is complete.)^
2056 ** The input to [sqlite3_complete()] must be a zero-terminated
2059 ** The input to [sqlite3_complete16()] must be a zero-terminated
2060 ** UTF-16 string in native byte order.
2062 SQLITE_API int sqlite3_complete(const char *sql);
2063 SQLITE_API int sqlite3_complete16(const void *sql);
2066 ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
2067 ** KEYWORDS: {busy-handler callback} {busy handler}
2069 ** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X
2070 ** that might be invoked with argument P whenever
2071 ** an attempt is made to access a database table associated with
2072 ** [database connection] D when another thread
2073 ** or process has the table locked.
2074 ** The sqlite3_busy_handler() interface is used to implement
2075 ** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout].
2077 ** ^If the busy callback is NULL, then [SQLITE_BUSY]
2078 ** is returned immediately upon encountering the lock. ^If the busy callback
2079 ** is not NULL, then the callback might be invoked with two arguments.
2081 ** ^The first argument to the busy handler is a copy of the void* pointer which
2082 ** is the third argument to sqlite3_busy_handler(). ^The second argument to
2083 ** the busy handler callback is the number of times that the busy handler has
2084 ** been invoked previously for the same locking event. ^If the
2085 ** busy callback returns 0, then no additional attempts are made to
2086 ** access the database and [SQLITE_BUSY] is returned
2087 ** to the application.
2088 ** ^If the callback returns non-zero, then another attempt
2089 ** is made to access the database and the cycle repeats.
2091 ** The presence of a busy handler does not guarantee that it will be invoked
2092 ** when there is lock contention. ^If SQLite determines that invoking the busy
2093 ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
2094 ** to the application instead of invoking the
2096 ** Consider a scenario where one process is holding a read lock that
2097 ** it is trying to promote to a reserved lock and
2098 ** a second process is holding a reserved lock that it is trying
2099 ** to promote to an exclusive lock. The first process cannot proceed
2100 ** because it is blocked by the second and the second process cannot
2101 ** proceed because it is blocked by the first. If both processes
2102 ** invoke the busy handlers, neither will make any progress. Therefore,
2103 ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
2104 ** will induce the first process to release its read lock and allow
2105 ** the second process to proceed.
2107 ** ^The default busy callback is NULL.
2109 ** ^(There can only be a single busy handler defined for each
2110 ** [database connection]. Setting a new busy handler clears any
2111 ** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()]
2112 ** or evaluating [PRAGMA busy_timeout=N] will change the
2113 ** busy handler and thus clear any previously set busy handler.
2115 ** The busy callback should not take any actions which modify the
2116 ** database connection that invoked the busy handler. In other words,
2117 ** the busy handler is not reentrant. Any such actions
2118 ** result in undefined behavior.
2120 ** A busy handler must not close the database connection
2121 ** or [prepared statement] that invoked the busy handler.
2123 SQLITE_API int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*);
2126 ** CAPI3REF: Set A Busy Timeout
2128 ** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
2129 ** for a specified amount of time when a table is locked. ^The handler
2130 ** will sleep multiple times until at least "ms" milliseconds of sleeping
2131 ** have accumulated. ^After at least "ms" milliseconds of sleeping,
2132 ** the handler returns 0 which causes [sqlite3_step()] to return
2135 ** ^Calling this routine with an argument less than or equal to zero
2136 ** turns off all busy handlers.
2138 ** ^(There can only be a single busy handler for a particular
2139 ** [database connection] at any given moment. If another busy handler
2140 ** was defined (using [sqlite3_busy_handler()]) prior to calling
2141 ** this routine, that other busy handler is cleared.)^
2143 ** See also: [PRAGMA busy_timeout]
2145 SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms);
2148 ** CAPI3REF: Convenience Routines For Running Queries
2150 ** This is a legacy interface that is preserved for backwards compatibility.
2151 ** Use of this interface is not recommended.
2153 ** Definition: A <b>result table</b> is memory data structure created by the
2154 ** [sqlite3_get_table()] interface. A result table records the
2155 ** complete query results from one or more queries.
2157 ** The table conceptually has a number of rows and columns. But
2158 ** these numbers are not part of the result table itself. These
2159 ** numbers are obtained separately. Let N be the number of rows
2160 ** and M be the number of columns.
2162 ** A result table is an array of pointers to zero-terminated UTF-8 strings.
2163 ** There are (N+1)*M elements in the array. The first M pointers point
2164 ** to zero-terminated strings that contain the names of the columns.
2165 ** The remaining entries all point to query results. NULL values result
2166 ** in NULL pointers. All other values are in their UTF-8 zero-terminated
2167 ** string representation as returned by [sqlite3_column_text()].
2169 ** A result table might consist of one or more memory allocations.
2170 ** It is not safe to pass a result table directly to [sqlite3_free()].
2171 ** A result table should be deallocated using [sqlite3_free_table()].
2173 ** ^(As an example of the result table format, suppose a query result
2176 ** <blockquote><pre>
2178 ** -----------------------
2182 ** </pre></blockquote>
2184 ** There are two column (M==2) and three rows (N==3). Thus the
2185 ** result table has 8 entries. Suppose the result table is stored
2186 ** in an array names azResult. Then azResult holds this content:
2188 ** <blockquote><pre>
2189 ** azResult[0] = "Name";
2190 ** azResult[1] = "Age";
2191 ** azResult[2] = "Alice";
2192 ** azResult[3] = "43";
2193 ** azResult[4] = "Bob";
2194 ** azResult[5] = "28";
2195 ** azResult[6] = "Cindy";
2196 ** azResult[7] = "21";
2197 ** </pre></blockquote>)^
2199 ** ^The sqlite3_get_table() function evaluates one or more
2200 ** semicolon-separated SQL statements in the zero-terminated UTF-8
2201 ** string of its 2nd parameter and returns a result table to the
2202 ** pointer given in its 3rd parameter.
2204 ** After the application has finished with the result from sqlite3_get_table(),
2205 ** it must pass the result table pointer to sqlite3_free_table() in order to
2206 ** release the memory that was malloced. Because of the way the
2207 ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
2208 ** function must not try to call [sqlite3_free()] directly. Only
2209 ** [sqlite3_free_table()] is able to release the memory properly and safely.
2211 ** The sqlite3_get_table() interface is implemented as a wrapper around
2212 ** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access
2213 ** to any internal data structures of SQLite. It uses only the public
2214 ** interface defined here. As a consequence, errors that occur in the
2215 ** wrapper layer outside of the internal [sqlite3_exec()] call are not
2216 ** reflected in subsequent calls to [sqlite3_errcode()] or
2217 ** [sqlite3_errmsg()].
2219 SQLITE_API int sqlite3_get_table(
2220 sqlite3 *db, /* An open database */
2221 const char *zSql, /* SQL to be evaluated */
2222 char ***pazResult, /* Results of the query */
2223 int *pnRow, /* Number of result rows written here */
2224 int *pnColumn, /* Number of result columns written here */
2225 char **pzErrmsg /* Error msg written here */
2227 SQLITE_API void sqlite3_free_table(char **result);
2230 ** CAPI3REF: Formatted String Printing Functions
2232 ** These routines are work-alikes of the "printf()" family of functions
2233 ** from the standard C library.
2235 ** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
2236 ** results into memory obtained from [sqlite3_malloc()].
2237 ** The strings returned by these two routines should be
2238 ** released by [sqlite3_free()]. ^Both routines return a
2239 ** NULL pointer if [sqlite3_malloc()] is unable to allocate enough
2240 ** memory to hold the resulting string.
2242 ** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
2243 ** the standard C library. The result is written into the
2244 ** buffer supplied as the second parameter whose size is given by
2245 ** the first parameter. Note that the order of the
2246 ** first two parameters is reversed from snprintf().)^ This is an
2247 ** historical accident that cannot be fixed without breaking
2248 ** backwards compatibility. ^(Note also that sqlite3_snprintf()
2249 ** returns a pointer to its buffer instead of the number of
2250 ** characters actually written into the buffer.)^ We admit that
2251 ** the number of characters written would be a more useful return
2252 ** value but we cannot change the implementation of sqlite3_snprintf()
2253 ** now without breaking compatibility.
2255 ** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
2256 ** guarantees that the buffer is always zero-terminated. ^The first
2257 ** parameter "n" is the total size of the buffer, including space for
2258 ** the zero terminator. So the longest string that can be completely
2259 ** written will be n-1 characters.
2261 ** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
2263 ** These routines all implement some additional formatting
2264 ** options that are useful for constructing SQL statements.
2265 ** All of the usual printf() formatting options apply. In addition, there
2266 ** is are "%q", "%Q", and "%z" options.
2268 ** ^(The %q option works like %s in that it substitutes a nul-terminated
2269 ** string from the argument list. But %q also doubles every '\'' character.
2270 ** %q is designed for use inside a string literal.)^ By doubling each '\''
2271 ** character it escapes that character and allows it to be inserted into
2274 ** For example, assume the string variable zText contains text as follows:
2276 ** <blockquote><pre>
2277 ** char *zText = "It's a happy day!";
2278 ** </pre></blockquote>
2280 ** One can use this text in an SQL statement as follows:
2282 ** <blockquote><pre>
2283 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText);
2284 ** sqlite3_exec(db, zSQL, 0, 0, 0);
2285 ** sqlite3_free(zSQL);
2286 ** </pre></blockquote>
2288 ** Because the %q format string is used, the '\'' character in zText
2289 ** is escaped and the SQL generated is as follows:
2291 ** <blockquote><pre>
2292 ** INSERT INTO table1 VALUES('It''s a happy day!')
2293 ** </pre></blockquote>
2295 ** This is correct. Had we used %s instead of %q, the generated SQL
2296 ** would have looked like this:
2298 ** <blockquote><pre>
2299 ** INSERT INTO table1 VALUES('It's a happy day!');
2300 ** </pre></blockquote>
2302 ** This second example is an SQL syntax error. As a general rule you should
2303 ** always use %q instead of %s when inserting text into a string literal.
2305 ** ^(The %Q option works like %q except it also adds single quotes around
2306 ** the outside of the total string. Additionally, if the parameter in the
2307 ** argument list is a NULL pointer, %Q substitutes the text "NULL" (without
2308 ** single quotes).)^ So, for example, one could say:
2310 ** <blockquote><pre>
2311 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText);
2312 ** sqlite3_exec(db, zSQL, 0, 0, 0);
2313 ** sqlite3_free(zSQL);
2314 ** </pre></blockquote>
2316 ** The code above will render a correct SQL statement in the zSQL
2317 ** variable even if the zText variable is a NULL pointer.
2319 ** ^(The "%z" formatting option works like "%s" but with the
2320 ** addition that after the string has been read and copied into
2321 ** the result, [sqlite3_free()] is called on the input string.)^
2323 SQLITE_API char *sqlite3_mprintf(const char*,...);
2324 SQLITE_API char *sqlite3_vmprintf(const char*, va_list);
2325 SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...);
2326 SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list);
2329 ** CAPI3REF: Memory Allocation Subsystem
2331 ** The SQLite core uses these three routines for all of its own
2332 ** internal memory allocation needs. "Core" in the previous sentence
2333 ** does not include operating-system specific VFS implementation. The
2334 ** Windows VFS uses native malloc() and free() for some operations.
2336 ** ^The sqlite3_malloc() routine returns a pointer to a block
2337 ** of memory at least N bytes in length, where N is the parameter.
2338 ** ^If sqlite3_malloc() is unable to obtain sufficient free
2339 ** memory, it returns a NULL pointer. ^If the parameter N to
2340 ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
2343 ** ^The sqlite3_malloc64(N) routine works just like
2344 ** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead
2345 ** of a signed 32-bit integer.
2347 ** ^Calling sqlite3_free() with a pointer previously returned
2348 ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
2349 ** that it might be reused. ^The sqlite3_free() routine is
2350 ** a no-op if is called with a NULL pointer. Passing a NULL pointer
2351 ** to sqlite3_free() is harmless. After being freed, memory
2352 ** should neither be read nor written. Even reading previously freed
2353 ** memory might result in a segmentation fault or other severe error.
2354 ** Memory corruption, a segmentation fault, or other severe error
2355 ** might result if sqlite3_free() is called with a non-NULL pointer that
2356 ** was not obtained from sqlite3_malloc() or sqlite3_realloc().
2358 ** ^The sqlite3_realloc(X,N) interface attempts to resize a
2359 ** prior memory allocation X to be at least N bytes.
2360 ** ^If the X parameter to sqlite3_realloc(X,N)
2361 ** is a NULL pointer then its behavior is identical to calling
2362 ** sqlite3_malloc(N).
2363 ** ^If the N parameter to sqlite3_realloc(X,N) is zero or
2364 ** negative then the behavior is exactly the same as calling
2366 ** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation
2367 ** of at least N bytes in size or NULL if insufficient memory is available.
2368 ** ^If M is the size of the prior allocation, then min(N,M) bytes
2369 ** of the prior allocation are copied into the beginning of buffer returned
2370 ** by sqlite3_realloc(X,N) and the prior allocation is freed.
2371 ** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the
2372 ** prior allocation is not freed.
2374 ** ^The sqlite3_realloc64(X,N) interfaces works the same as
2375 ** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead
2376 ** of a 32-bit signed integer.
2378 ** ^If X is a memory allocation previously obtained from sqlite3_malloc(),
2379 ** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then
2380 ** sqlite3_msize(X) returns the size of that memory allocation in bytes.
2381 ** ^The value returned by sqlite3_msize(X) might be larger than the number
2382 ** of bytes requested when X was allocated. ^If X is a NULL pointer then
2383 ** sqlite3_msize(X) returns zero. If X points to something that is not
2384 ** the beginning of memory allocation, or if it points to a formerly
2385 ** valid memory allocation that has now been freed, then the behavior
2386 ** of sqlite3_msize(X) is undefined and possibly harmful.
2388 ** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(),
2389 ** sqlite3_malloc64(), and sqlite3_realloc64()
2390 ** is always aligned to at least an 8 byte boundary, or to a
2391 ** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
2394 ** In SQLite version 3.5.0 and 3.5.1, it was possible to define
2395 ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in
2396 ** implementation of these routines to be omitted. That capability
2397 ** is no longer provided. Only built-in memory allocators can be used.
2399 ** Prior to SQLite version 3.7.10, the Windows OS interface layer called
2400 ** the system malloc() and free() directly when converting
2401 ** filenames between the UTF-8 encoding used by SQLite
2402 ** and whatever filename encoding is used by the particular Windows
2403 ** installation. Memory allocation errors were detected, but
2404 ** they were reported back as [SQLITE_CANTOPEN] or
2405 ** [SQLITE_IOERR] rather than [SQLITE_NOMEM].
2407 ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
2408 ** must be either NULL or else pointers obtained from a prior
2409 ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
2410 ** not yet been released.
2412 ** The application must not read or write any part of
2413 ** a block of memory after it has been released using
2414 ** [sqlite3_free()] or [sqlite3_realloc()].
2416 SQLITE_API void *sqlite3_malloc(int);
2417 SQLITE_API void *sqlite3_malloc64(sqlite3_uint64);
2418 SQLITE_API void *sqlite3_realloc(void*, int);
2419 SQLITE_API void *sqlite3_realloc64(void*, sqlite3_uint64);
2420 SQLITE_API void sqlite3_free(void*);
2421 SQLITE_API sqlite3_uint64 sqlite3_msize(void*);
2424 ** CAPI3REF: Memory Allocator Statistics
2426 ** SQLite provides these two interfaces for reporting on the status
2427 ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
2428 ** routines, which form the built-in memory allocation subsystem.
2430 ** ^The [sqlite3_memory_used()] routine returns the number of bytes
2431 ** of memory currently outstanding (malloced but not freed).
2432 ** ^The [sqlite3_memory_highwater()] routine returns the maximum
2433 ** value of [sqlite3_memory_used()] since the high-water mark
2434 ** was last reset. ^The values returned by [sqlite3_memory_used()] and
2435 ** [sqlite3_memory_highwater()] include any overhead
2436 ** added by SQLite in its implementation of [sqlite3_malloc()],
2437 ** but not overhead added by the any underlying system library
2438 ** routines that [sqlite3_malloc()] may call.
2440 ** ^The memory high-water mark is reset to the current value of
2441 ** [sqlite3_memory_used()] if and only if the parameter to
2442 ** [sqlite3_memory_highwater()] is true. ^The value returned
2443 ** by [sqlite3_memory_highwater(1)] is the high-water mark
2444 ** prior to the reset.
2446 SQLITE_API sqlite3_int64 sqlite3_memory_used(void);
2447 SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
2450 ** CAPI3REF: Pseudo-Random Number Generator
2452 ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
2453 ** select random [ROWID | ROWIDs] when inserting new records into a table that
2454 ** already uses the largest possible [ROWID]. The PRNG is also used for
2455 ** the build-in random() and randomblob() SQL functions. This interface allows
2456 ** applications to access the same PRNG for other purposes.
2458 ** ^A call to this routine stores N bytes of randomness into buffer P.
2459 ** ^The P parameter can be a NULL pointer.
2461 ** ^If this routine has not been previously called or if the previous
2462 ** call had N less than one or a NULL pointer for P, then the PRNG is
2463 ** seeded using randomness obtained from the xRandomness method of
2464 ** the default [sqlite3_vfs] object.
2465 ** ^If the previous call to this routine had an N of 1 or more and a
2466 ** non-NULL P then the pseudo-randomness is generated
2467 ** internally and without recourse to the [sqlite3_vfs] xRandomness
2470 SQLITE_API void sqlite3_randomness(int N, void *P);
2473 ** CAPI3REF: Compile-Time Authorization Callbacks
2475 ** ^This routine registers an authorizer callback with a particular
2476 ** [database connection], supplied in the first argument.
2477 ** ^The authorizer callback is invoked as SQL statements are being compiled
2478 ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
2479 ** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various
2480 ** points during the compilation process, as logic is being created
2481 ** to perform various actions, the authorizer callback is invoked to
2482 ** see if those actions are allowed. ^The authorizer callback should
2483 ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
2484 ** specific action but allow the SQL statement to continue to be
2485 ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
2486 ** rejected with an error. ^If the authorizer callback returns
2487 ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
2488 ** then the [sqlite3_prepare_v2()] or equivalent call that triggered
2489 ** the authorizer will fail with an error message.
2491 ** When the callback returns [SQLITE_OK], that means the operation
2492 ** requested is ok. ^When the callback returns [SQLITE_DENY], the
2493 ** [sqlite3_prepare_v2()] or equivalent call that triggered the
2494 ** authorizer will fail with an error message explaining that
2495 ** access is denied.
2497 ** ^The first parameter to the authorizer callback is a copy of the third
2498 ** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
2499 ** to the callback is an integer [SQLITE_COPY | action code] that specifies
2500 ** the particular action to be authorized. ^The third through sixth parameters
2501 ** to the callback are zero-terminated strings that contain additional
2502 ** details about the action to be authorized.
2504 ** ^If the action code is [SQLITE_READ]
2505 ** and the callback returns [SQLITE_IGNORE] then the
2506 ** [prepared statement] statement is constructed to substitute
2507 ** a NULL value in place of the table column that would have
2508 ** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE]
2509 ** return can be used to deny an untrusted user access to individual
2510 ** columns of a table.
2511 ** ^If the action code is [SQLITE_DELETE] and the callback returns
2512 ** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
2513 ** [truncate optimization] is disabled and all rows are deleted individually.
2515 ** An authorizer is used when [sqlite3_prepare | preparing]
2516 ** SQL statements from an untrusted source, to ensure that the SQL statements
2517 ** do not try to access data they are not allowed to see, or that they do not
2518 ** try to execute malicious statements that damage the database. For
2519 ** example, an application may allow a user to enter arbitrary
2520 ** SQL queries for evaluation by a database. But the application does
2521 ** not want the user to be able to make arbitrary changes to the
2522 ** database. An authorizer could then be put in place while the
2523 ** user-entered SQL is being [sqlite3_prepare | prepared] that
2524 ** disallows everything except [SELECT] statements.
2526 ** Applications that need to process SQL from untrusted sources
2527 ** might also consider lowering resource limits using [sqlite3_limit()]
2528 ** and limiting database size using the [max_page_count] [PRAGMA]
2529 ** in addition to using an authorizer.
2531 ** ^(Only a single authorizer can be in place on a database connection
2532 ** at a time. Each call to sqlite3_set_authorizer overrides the
2533 ** previous call.)^ ^Disable the authorizer by installing a NULL callback.
2534 ** The authorizer is disabled by default.
2536 ** The authorizer callback must not do anything that will modify
2537 ** the database connection that invoked the authorizer callback.
2538 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2539 ** database connections for the meaning of "modify" in this paragraph.
2541 ** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
2542 ** statement might be re-prepared during [sqlite3_step()] due to a
2543 ** schema change. Hence, the application should ensure that the
2544 ** correct authorizer callback remains in place during the [sqlite3_step()].
2546 ** ^Note that the authorizer callback is invoked only during
2547 ** [sqlite3_prepare()] or its variants. Authorization is not
2548 ** performed during statement evaluation in [sqlite3_step()], unless
2549 ** as stated in the previous paragraph, sqlite3_step() invokes
2550 ** sqlite3_prepare_v2() to reprepare a statement after a schema change.
2552 SQLITE_API int sqlite3_set_authorizer(
2554 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
2559 ** CAPI3REF: Authorizer Return Codes
2561 ** The [sqlite3_set_authorizer | authorizer callback function] must
2562 ** return either [SQLITE_OK] or one of these two constants in order
2563 ** to signal SQLite whether or not the action is permitted. See the
2564 ** [sqlite3_set_authorizer | authorizer documentation] for additional
2567 ** Note that SQLITE_IGNORE is also used as a [conflict resolution mode]
2568 ** returned from the [sqlite3_vtab_on_conflict()] interface.
2570 #define SQLITE_DENY 1 /* Abort the SQL statement with an error */
2571 #define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */
2574 ** CAPI3REF: Authorizer Action Codes
2576 ** The [sqlite3_set_authorizer()] interface registers a callback function
2577 ** that is invoked to authorize certain SQL statement actions. The
2578 ** second parameter to the callback is an integer code that specifies
2579 ** what action is being authorized. These are the integer action codes that
2580 ** the authorizer callback may be passed.
2582 ** These action code values signify what kind of operation is to be
2583 ** authorized. The 3rd and 4th parameters to the authorization
2584 ** callback function will be parameters or NULL depending on which of these
2585 ** codes is used as the second parameter. ^(The 5th parameter to the
2586 ** authorizer callback is the name of the database ("main", "temp",
2587 ** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback
2588 ** is the name of the inner-most trigger or view that is responsible for
2589 ** the access attempt or NULL if this access attempt is directly from
2590 ** top-level SQL code.
2592 /******************************************* 3rd ************ 4th ***********/
2593 #define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */
2594 #define SQLITE_CREATE_TABLE 2 /* Table Name NULL */
2595 #define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */
2596 #define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */
2597 #define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */
2598 #define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */
2599 #define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */
2600 #define SQLITE_CREATE_VIEW 8 /* View Name NULL */
2601 #define SQLITE_DELETE 9 /* Table Name NULL */
2602 #define SQLITE_DROP_INDEX 10 /* Index Name Table Name */
2603 #define SQLITE_DROP_TABLE 11 /* Table Name NULL */
2604 #define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */
2605 #define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */
2606 #define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */
2607 #define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */
2608 #define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */
2609 #define SQLITE_DROP_VIEW 17 /* View Name NULL */
2610 #define SQLITE_INSERT 18 /* Table Name NULL */
2611 #define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */
2612 #define SQLITE_READ 20 /* Table Name Column Name */
2613 #define SQLITE_SELECT 21 /* NULL NULL */
2614 #define SQLITE_TRANSACTION 22 /* Operation NULL */
2615 #define SQLITE_UPDATE 23 /* Table Name Column Name */
2616 #define SQLITE_ATTACH 24 /* Filename NULL */
2617 #define SQLITE_DETACH 25 /* Database Name NULL */
2618 #define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */
2619 #define SQLITE_REINDEX 27 /* Index Name NULL */
2620 #define SQLITE_ANALYZE 28 /* Table Name NULL */
2621 #define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */
2622 #define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */
2623 #define SQLITE_FUNCTION 31 /* NULL Function Name */
2624 #define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */
2625 #define SQLITE_COPY 0 /* No longer used */
2626 #define SQLITE_RECURSIVE 33 /* NULL NULL */
2629 ** CAPI3REF: Tracing And Profiling Functions
2631 ** These routines register callback functions that can be used for
2632 ** tracing and profiling the execution of SQL statements.
2634 ** ^The callback function registered by sqlite3_trace() is invoked at
2635 ** various times when an SQL statement is being run by [sqlite3_step()].
2636 ** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
2637 ** SQL statement text as the statement first begins executing.
2638 ** ^(Additional sqlite3_trace() callbacks might occur
2639 ** as each triggered subprogram is entered. The callbacks for triggers
2640 ** contain a UTF-8 SQL comment that identifies the trigger.)^
2642 ** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit
2643 ** the length of [bound parameter] expansion in the output of sqlite3_trace().
2645 ** ^The callback function registered by sqlite3_profile() is invoked
2646 ** as each SQL statement finishes. ^The profile callback contains
2647 ** the original statement text and an estimate of wall-clock time
2648 ** of how long that statement took to run. ^The profile callback
2649 ** time is in units of nanoseconds, however the current implementation
2650 ** is only capable of millisecond resolution so the six least significant
2651 ** digits in the time are meaningless. Future versions of SQLite
2652 ** might provide greater resolution on the profiler callback. The
2653 ** sqlite3_profile() function is considered experimental and is
2654 ** subject to change in future versions of SQLite.
2656 SQLITE_API void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*);
2657 SQLITE_API SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*,
2658 void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
2661 ** CAPI3REF: Query Progress Callbacks
2663 ** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
2664 ** function X to be invoked periodically during long running calls to
2665 ** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for
2666 ** database connection D. An example use for this
2667 ** interface is to keep a GUI updated during a large query.
2669 ** ^The parameter P is passed through as the only parameter to the
2670 ** callback function X. ^The parameter N is the approximate number of
2671 ** [virtual machine instructions] that are evaluated between successive
2672 ** invocations of the callback X. ^If N is less than one then the progress
2673 ** handler is disabled.
2675 ** ^Only a single progress handler may be defined at one time per
2676 ** [database connection]; setting a new progress handler cancels the
2677 ** old one. ^Setting parameter X to NULL disables the progress handler.
2678 ** ^The progress handler is also disabled by setting N to a value less
2681 ** ^If the progress callback returns non-zero, the operation is
2682 ** interrupted. This feature can be used to implement a
2683 ** "Cancel" button on a GUI progress dialog box.
2685 ** The progress handler callback must not do anything that will modify
2686 ** the database connection that invoked the progress handler.
2687 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2688 ** database connections for the meaning of "modify" in this paragraph.
2691 SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
2694 ** CAPI3REF: Opening A New Database Connection
2696 ** ^These routines open an SQLite database file as specified by the
2697 ** filename argument. ^The filename argument is interpreted as UTF-8 for
2698 ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
2699 ** order for sqlite3_open16(). ^(A [database connection] handle is usually
2700 ** returned in *ppDb, even if an error occurs. The only exception is that
2701 ** if SQLite is unable to allocate memory to hold the [sqlite3] object,
2702 ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
2703 ** object.)^ ^(If the database is opened (and/or created) successfully, then
2704 ** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The
2705 ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
2706 ** an English language description of the error following a failure of any
2707 ** of the sqlite3_open() routines.
2709 ** ^The default encoding will be UTF-8 for databases created using
2710 ** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases
2711 ** created using sqlite3_open16() will be UTF-16 in the native byte order.
2713 ** Whether or not an error occurs when it is opened, resources
2714 ** associated with the [database connection] handle should be released by
2715 ** passing it to [sqlite3_close()] when it is no longer required.
2717 ** The sqlite3_open_v2() interface works like sqlite3_open()
2718 ** except that it accepts two additional parameters for additional control
2719 ** over the new database connection. ^(The flags parameter to
2720 ** sqlite3_open_v2() can take one of
2721 ** the following three values, optionally combined with the
2722 ** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE],
2723 ** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^
2726 ** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
2727 ** <dd>The database is opened in read-only mode. If the database does not
2728 ** already exist, an error is returned.</dd>)^
2730 ** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
2731 ** <dd>The database is opened for reading and writing if possible, or reading
2732 ** only if the file is write protected by the operating system. In either
2733 ** case the database must already exist, otherwise an error is returned.</dd>)^
2735 ** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
2736 ** <dd>The database is opened for reading and writing, and is created if
2737 ** it does not already exist. This is the behavior that is always used for
2738 ** sqlite3_open() and sqlite3_open16().</dd>)^
2741 ** If the 3rd parameter to sqlite3_open_v2() is not one of the
2742 ** combinations shown above optionally combined with other
2743 ** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits]
2744 ** then the behavior is undefined.
2746 ** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection
2747 ** opens in the multi-thread [threading mode] as long as the single-thread
2748 ** mode has not been set at compile-time or start-time. ^If the
2749 ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens
2750 ** in the serialized [threading mode] unless single-thread was
2751 ** previously selected at compile-time or start-time.
2752 ** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be
2753 ** eligible to use [shared cache mode], regardless of whether or not shared
2754 ** cache is enabled using [sqlite3_enable_shared_cache()]. ^The
2755 ** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not
2756 ** participate in [shared cache mode] even if it is enabled.
2758 ** ^The fourth parameter to sqlite3_open_v2() is the name of the
2759 ** [sqlite3_vfs] object that defines the operating system interface that
2760 ** the new database connection should use. ^If the fourth parameter is
2761 ** a NULL pointer then the default [sqlite3_vfs] object is used.
2763 ** ^If the filename is ":memory:", then a private, temporary in-memory database
2764 ** is created for the connection. ^This in-memory database will vanish when
2765 ** the database connection is closed. Future versions of SQLite might
2766 ** make use of additional special filenames that begin with the ":" character.
2767 ** It is recommended that when a database filename actually does begin with
2768 ** a ":" character you should prefix the filename with a pathname such as
2769 ** "./" to avoid ambiguity.
2771 ** ^If the filename is an empty string, then a private, temporary
2772 ** on-disk database will be created. ^This private database will be
2773 ** automatically deleted as soon as the database connection is closed.
2775 ** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
2777 ** ^If [URI filename] interpretation is enabled, and the filename argument
2778 ** begins with "file:", then the filename is interpreted as a URI. ^URI
2779 ** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
2780 ** set in the fourth argument to sqlite3_open_v2(), or if it has
2781 ** been enabled globally using the [SQLITE_CONFIG_URI] option with the
2782 ** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
2783 ** As of SQLite version 3.7.7, URI filename interpretation is turned off
2784 ** by default, but future releases of SQLite might enable URI filename
2785 ** interpretation by default. See "[URI filenames]" for additional
2788 ** URI filenames are parsed according to RFC 3986. ^If the URI contains an
2789 ** authority, then it must be either an empty string or the string
2790 ** "localhost". ^If the authority is not an empty string or "localhost", an
2791 ** error is returned to the caller. ^The fragment component of a URI, if
2792 ** present, is ignored.
2794 ** ^SQLite uses the path component of the URI as the name of the disk file
2795 ** which contains the database. ^If the path begins with a '/' character,
2796 ** then it is interpreted as an absolute path. ^If the path does not begin
2797 ** with a '/' (meaning that the authority section is omitted from the URI)
2798 ** then the path is interpreted as a relative path.
2799 ** ^(On windows, the first component of an absolute path
2800 ** is a drive specification (e.g. "C:").)^
2802 ** [[core URI query parameters]]
2803 ** The query component of a URI may contain parameters that are interpreted
2804 ** either by SQLite itself, or by a [VFS | custom VFS implementation].
2805 ** SQLite and its built-in [VFSes] interpret the
2806 ** following query parameters:
2809 ** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
2810 ** a VFS object that provides the operating system interface that should
2811 ** be used to access the database file on disk. ^If this option is set to
2812 ** an empty string the default VFS object is used. ^Specifying an unknown
2813 ** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
2814 ** present, then the VFS specified by the option takes precedence over
2815 ** the value passed as the fourth parameter to sqlite3_open_v2().
2817 ** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw",
2818 ** "rwc", or "memory". Attempting to set it to any other value is
2820 ** ^If "ro" is specified, then the database is opened for read-only
2821 ** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the
2822 ** third argument to sqlite3_open_v2(). ^If the mode option is set to
2823 ** "rw", then the database is opened for read-write (but not create)
2824 ** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had
2825 ** been set. ^Value "rwc" is equivalent to setting both
2826 ** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is
2827 ** set to "memory" then a pure [in-memory database] that never reads
2828 ** or writes from disk is used. ^It is an error to specify a value for
2829 ** the mode parameter that is less restrictive than that specified by
2830 ** the flags passed in the third parameter to sqlite3_open_v2().
2832 ** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
2833 ** "private". ^Setting it to "shared" is equivalent to setting the
2834 ** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
2835 ** sqlite3_open_v2(). ^Setting the cache parameter to "private" is
2836 ** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
2837 ** ^If sqlite3_open_v2() is used and the "cache" parameter is present in
2838 ** a URI filename, its value overrides any behavior requested by setting
2839 ** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.
2841 ** <li> <b>psow</b>: ^The psow parameter indicates whether or not the
2842 ** [powersafe overwrite] property does or does not apply to the
2843 ** storage media on which the database file resides.
2845 ** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter
2846 ** which if set disables file locking in rollback journal modes. This
2847 ** is useful for accessing a database on a filesystem that does not
2848 ** support locking. Caution: Database corruption might result if two
2849 ** or more processes write to the same database and any one of those
2850 ** processes uses nolock=1.
2852 ** <li> <b>immutable</b>: ^The immutable parameter is a boolean query
2853 ** parameter that indicates that the database file is stored on
2854 ** read-only media. ^When immutable is set, SQLite assumes that the
2855 ** database file cannot be changed, even by a process with higher
2856 ** privilege, and so the database is opened read-only and all locking
2857 ** and change detection is disabled. Caution: Setting the immutable
2858 ** property on a database file that does in fact change can result
2859 ** in incorrect query results and/or [SQLITE_CORRUPT] errors.
2860 ** See also: [SQLITE_IOCAP_IMMUTABLE].
2864 ** ^Specifying an unknown parameter in the query component of a URI is not an
2865 ** error. Future versions of SQLite might understand additional query
2866 ** parameters. See "[query parameters with special meaning to SQLite]" for
2867 ** additional information.
2869 ** [[URI filename examples]] <h3>URI filename examples</h3>
2871 ** <table border="1" align=center cellpadding=5>
2872 ** <tr><th> URI filenames <th> Results
2873 ** <tr><td> file:data.db <td>
2874 ** Open the file "data.db" in the current directory.
2875 ** <tr><td> file:/home/fred/data.db<br>
2876 ** file:///home/fred/data.db <br>
2877 ** file://localhost/home/fred/data.db <br> <td>
2878 ** Open the database file "/home/fred/data.db".
2879 ** <tr><td> file://darkstar/home/fred/data.db <td>
2880 ** An error. "darkstar" is not a recognized authority.
2881 ** <tr><td style="white-space:nowrap">
2882 ** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
2883 ** <td> Windows only: Open the file "data.db" on fred's desktop on drive
2884 ** C:. Note that the %20 escaping in this example is not strictly
2885 ** necessary - space characters can be used literally
2886 ** in URI filenames.
2887 ** <tr><td> file:data.db?mode=ro&cache=private <td>
2888 ** Open file "data.db" in the current directory for read-only access.
2889 ** Regardless of whether or not shared-cache mode is enabled by
2890 ** default, use a private cache.
2891 ** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td>
2892 ** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile"
2893 ** that uses dot-files in place of posix advisory locking.
2894 ** <tr><td> file:data.db?mode=readonly <td>
2895 ** An error. "readonly" is not a valid option for the "mode" parameter.
2898 ** ^URI hexadecimal escape sequences (%HH) are supported within the path and
2899 ** query components of a URI. A hexadecimal escape sequence consists of a
2900 ** percent sign - "%" - followed by exactly two hexadecimal digits
2901 ** specifying an octet value. ^Before the path or query components of a
2902 ** URI filename are interpreted, they are encoded using UTF-8 and all
2903 ** hexadecimal escape sequences replaced by a single byte containing the
2904 ** corresponding octet. If this process generates an invalid UTF-8 encoding,
2905 ** the results are undefined.
2907 ** <b>Note to Windows users:</b> The encoding used for the filename argument
2908 ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
2909 ** codepage is currently defined. Filenames containing international
2910 ** characters must be converted to UTF-8 prior to passing them into
2911 ** sqlite3_open() or sqlite3_open_v2().
2913 ** <b>Note to Windows Runtime users:</b> The temporary directory must be set
2914 ** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various
2915 ** features that require the use of temporary files may fail.
2917 ** See also: [sqlite3_temp_directory]
2919 SQLITE_API int sqlite3_open(
2920 const char *filename, /* Database filename (UTF-8) */
2921 sqlite3 **ppDb /* OUT: SQLite db handle */
2923 SQLITE_API int sqlite3_open16(
2924 const void *filename, /* Database filename (UTF-16) */
2925 sqlite3 **ppDb /* OUT: SQLite db handle */
2927 SQLITE_API int sqlite3_open_v2(
2928 const char *filename, /* Database filename (UTF-8) */
2929 sqlite3 **ppDb, /* OUT: SQLite db handle */
2930 int flags, /* Flags */
2931 const char *zVfs /* Name of VFS module to use */
2935 ** CAPI3REF: Obtain Values For URI Parameters
2937 ** These are utility routines, useful to VFS implementations, that check
2938 ** to see if a database file was a URI that contained a specific query
2939 ** parameter, and if so obtains the value of that query parameter.
2941 ** If F is the database filename pointer passed into the xOpen() method of
2942 ** a VFS implementation when the flags parameter to xOpen() has one or
2943 ** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and
2944 ** P is the name of the query parameter, then
2945 ** sqlite3_uri_parameter(F,P) returns the value of the P
2946 ** parameter if it exists or a NULL pointer if P does not appear as a
2947 ** query parameter on F. If P is a query parameter of F
2948 ** has no explicit value, then sqlite3_uri_parameter(F,P) returns
2949 ** a pointer to an empty string.
2951 ** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
2952 ** parameter and returns true (1) or false (0) according to the value
2953 ** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
2954 ** value of query parameter P is one of "yes", "true", or "on" in any
2955 ** case or if the value begins with a non-zero number. The
2956 ** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
2957 ** query parameter P is one of "no", "false", or "off" in any case or
2958 ** if the value begins with a numeric zero. If P is not a query
2959 ** parameter on F or if the value of P is does not match any of the
2960 ** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).
2962 ** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
2963 ** 64-bit signed integer and returns that integer, or D if P does not
2964 ** exist. If the value of P is something other than an integer, then
2965 ** zero is returned.
2967 ** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
2968 ** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and
2969 ** is not a database file pathname pointer that SQLite passed into the xOpen
2970 ** VFS method, then the behavior of this routine is undefined and probably
2973 SQLITE_API const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam);
2974 SQLITE_API int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault);
2975 SQLITE_API sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64);
2979 ** CAPI3REF: Error Codes And Messages
2981 ** ^The sqlite3_errcode() interface returns the numeric [result code] or
2982 ** [extended result code] for the most recent failed sqlite3_* API call
2983 ** associated with a [database connection]. If a prior API call failed
2984 ** but the most recent API call succeeded, the return value from
2985 ** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode()
2986 ** interface is the same except that it always returns the
2987 ** [extended result code] even when extended result codes are
2990 ** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
2991 ** text that describes the error, as either UTF-8 or UTF-16 respectively.
2992 ** ^(Memory to hold the error message string is managed internally.
2993 ** The application does not need to worry about freeing the result.
2994 ** However, the error string might be overwritten or deallocated by
2995 ** subsequent calls to other SQLite interface functions.)^
2997 ** ^The sqlite3_errstr() interface returns the English-language text
2998 ** that describes the [result code], as UTF-8.
2999 ** ^(Memory to hold the error message string is managed internally
3000 ** and must not be freed by the application)^.
3002 ** When the serialized [threading mode] is in use, it might be the
3003 ** case that a second error occurs on a separate thread in between
3004 ** the time of the first error and the call to these interfaces.
3005 ** When that happens, the second error will be reported since these
3006 ** interfaces always report the most recent result. To avoid
3007 ** this, each thread can obtain exclusive use of the [database connection] D
3008 ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
3009 ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
3010 ** all calls to the interfaces listed here are completed.
3012 ** If an interface fails with SQLITE_MISUSE, that means the interface
3013 ** was invoked incorrectly by the application. In that case, the
3014 ** error code and message may or may not be set.
3016 SQLITE_API int sqlite3_errcode(sqlite3 *db);
3017 SQLITE_API int sqlite3_extended_errcode(sqlite3 *db);
3018 SQLITE_API const char *sqlite3_errmsg(sqlite3*);
3019 SQLITE_API const void *sqlite3_errmsg16(sqlite3*);
3020 SQLITE_API const char *sqlite3_errstr(int);
3023 ** CAPI3REF: SQL Statement Object
3024 ** KEYWORDS: {prepared statement} {prepared statements}
3026 ** An instance of this object represents a single SQL statement.
3027 ** This object is variously known as a "prepared statement" or a
3028 ** "compiled SQL statement" or simply as a "statement".
3030 ** The life of a statement object goes something like this:
3033 ** <li> Create the object using [sqlite3_prepare_v2()] or a related
3035 ** <li> Bind values to [host parameters] using the sqlite3_bind_*()
3037 ** <li> Run the SQL by calling [sqlite3_step()] one or more times.
3038 ** <li> Reset the statement using [sqlite3_reset()] then go back
3039 ** to step 2. Do this zero or more times.
3040 ** <li> Destroy the object using [sqlite3_finalize()].
3043 ** Refer to documentation on individual methods above for additional
3046 typedef struct sqlite3_stmt sqlite3_stmt;
3049 ** CAPI3REF: Run-time Limits
3051 ** ^(This interface allows the size of various constructs to be limited
3052 ** on a connection by connection basis. The first parameter is the
3053 ** [database connection] whose limit is to be set or queried. The
3054 ** second parameter is one of the [limit categories] that define a
3055 ** class of constructs to be size limited. The third parameter is the
3056 ** new limit for that construct.)^
3058 ** ^If the new limit is a negative number, the limit is unchanged.
3059 ** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
3060 ** [limits | hard upper bound]
3061 ** set at compile-time by a C preprocessor macro called
3062 ** [limits | SQLITE_MAX_<i>NAME</i>].
3063 ** (The "_LIMIT_" in the name is changed to "_MAX_".))^
3064 ** ^Attempts to increase a limit above its hard upper bound are
3065 ** silently truncated to the hard upper bound.
3067 ** ^Regardless of whether or not the limit was changed, the
3068 ** [sqlite3_limit()] interface returns the prior value of the limit.
3069 ** ^Hence, to find the current value of a limit without changing it,
3070 ** simply invoke this interface with the third parameter set to -1.
3072 ** Run-time limits are intended for use in applications that manage
3073 ** both their own internal database and also databases that are controlled
3074 ** by untrusted external sources. An example application might be a
3075 ** web browser that has its own databases for storing history and
3076 ** separate databases controlled by JavaScript applications downloaded
3077 ** off the Internet. The internal databases can be given the
3078 ** large, default limits. Databases managed by external sources can
3079 ** be given much smaller limits designed to prevent a denial of service
3080 ** attack. Developers might also want to use the [sqlite3_set_authorizer()]
3081 ** interface to further control untrusted SQL. The size of the database
3082 ** created by an untrusted script can be contained using the
3083 ** [max_page_count] [PRAGMA].
3085 ** New run-time limit categories may be added in future releases.
3087 SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal);
3090 ** CAPI3REF: Run-Time Limit Categories
3091 ** KEYWORDS: {limit category} {*limit categories}
3093 ** These constants define various performance limits
3094 ** that can be lowered at run-time using [sqlite3_limit()].
3095 ** The synopsis of the meanings of the various limits is shown below.
3096 ** Additional information is available at [limits | Limits in SQLite].
3099 ** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt>
3100 ** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
3102 ** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
3103 ** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
3105 ** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt>
3106 ** <dd>The maximum number of columns in a table definition or in the
3107 ** result set of a [SELECT] or the maximum number of columns in an index
3108 ** or in an ORDER BY or GROUP BY clause.</dd>)^
3110 ** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
3111 ** <dd>The maximum depth of the parse tree on any expression.</dd>)^
3113 ** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
3114 ** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
3116 ** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
3117 ** <dd>The maximum number of instructions in a virtual machine program
3118 ** used to implement an SQL statement. This limit is not currently
3119 ** enforced, though that might be added in some future release of
3122 ** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
3123 ** <dd>The maximum number of arguments on a function.</dd>)^
3125 ** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
3126 ** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
3128 ** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]]
3129 ** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
3130 ** <dd>The maximum length of the pattern argument to the [LIKE] or
3131 ** [GLOB] operators.</dd>)^
3133 ** [[SQLITE_LIMIT_VARIABLE_NUMBER]]
3134 ** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
3135 ** <dd>The maximum index number of any [parameter] in an SQL statement.)^
3137 ** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
3138 ** <dd>The maximum depth of recursion for triggers.</dd>)^
3140 ** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt>
3141 ** <dd>The maximum number of auxiliary worker threads that a single
3142 ** [prepared statement] may start.</dd>)^
3145 #define SQLITE_LIMIT_LENGTH 0
3146 #define SQLITE_LIMIT_SQL_LENGTH 1
3147 #define SQLITE_LIMIT_COLUMN 2
3148 #define SQLITE_LIMIT_EXPR_DEPTH 3
3149 #define SQLITE_LIMIT_COMPOUND_SELECT 4
3150 #define SQLITE_LIMIT_VDBE_OP 5
3151 #define SQLITE_LIMIT_FUNCTION_ARG 6
3152 #define SQLITE_LIMIT_ATTACHED 7
3153 #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8
3154 #define SQLITE_LIMIT_VARIABLE_NUMBER 9
3155 #define SQLITE_LIMIT_TRIGGER_DEPTH 10
3156 #define SQLITE_LIMIT_WORKER_THREADS 11
3159 ** CAPI3REF: Compiling An SQL Statement
3160 ** KEYWORDS: {SQL statement compiler}
3162 ** To execute an SQL query, it must first be compiled into a byte-code
3163 ** program using one of these routines.
3165 ** The first argument, "db", is a [database connection] obtained from a
3166 ** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
3167 ** [sqlite3_open16()]. The database connection must not have been closed.
3169 ** The second argument, "zSql", is the statement to be compiled, encoded
3170 ** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2()
3171 ** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2()
3174 ** ^If the nByte argument is less than zero, then zSql is read up to the
3175 ** first zero terminator. ^If nByte is non-negative, then it is the maximum
3176 ** number of bytes read from zSql. ^When nByte is non-negative, the
3177 ** zSql string ends at either the first '\000' or '\u0000' character or
3178 ** the nByte-th byte, whichever comes first. If the caller knows
3179 ** that the supplied string is nul-terminated, then there is a small
3180 ** performance advantage to be gained by passing an nByte parameter that
3181 ** is equal to the number of bytes in the input string <i>including</i>
3182 ** the nul-terminator bytes as this saves SQLite from having to
3183 ** make a copy of the input string.
3185 ** ^If pzTail is not NULL then *pzTail is made to point to the first byte
3186 ** past the end of the first SQL statement in zSql. These routines only
3187 ** compile the first statement in zSql, so *pzTail is left pointing to
3188 ** what remains uncompiled.
3190 ** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
3191 ** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set
3192 ** to NULL. ^If the input text contains no SQL (if the input is an empty
3193 ** string or a comment) then *ppStmt is set to NULL.
3194 ** The calling procedure is responsible for deleting the compiled
3195 ** SQL statement using [sqlite3_finalize()] after it has finished with it.
3196 ** ppStmt may not be NULL.
3198 ** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
3199 ** otherwise an [error code] is returned.
3201 ** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are
3202 ** recommended for all new programs. The two older interfaces are retained
3203 ** for backwards compatibility, but their use is discouraged.
3204 ** ^In the "v2" interfaces, the prepared statement
3205 ** that is returned (the [sqlite3_stmt] object) contains a copy of the
3206 ** original SQL text. This causes the [sqlite3_step()] interface to
3207 ** behave differently in three ways:
3211 ** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
3212 ** always used to do, [sqlite3_step()] will automatically recompile the SQL
3213 ** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY]
3214 ** retries will occur before sqlite3_step() gives up and returns an error.
3218 ** ^When an error occurs, [sqlite3_step()] will return one of the detailed
3219 ** [error codes] or [extended error codes]. ^The legacy behavior was that
3220 ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
3221 ** and the application would have to make a second call to [sqlite3_reset()]
3222 ** in order to find the underlying cause of the problem. With the "v2" prepare
3223 ** interfaces, the underlying reason for the error is returned immediately.
3227 ** ^If the specific value bound to [parameter | host parameter] in the
3228 ** WHERE clause might influence the choice of query plan for a statement,
3229 ** then the statement will be automatically recompiled, as if there had been
3230 ** a schema change, on the first [sqlite3_step()] call following any change
3231 ** to the [sqlite3_bind_text | bindings] of that [parameter].
3232 ** ^The specific value of WHERE-clause [parameter] might influence the
3233 ** choice of query plan if the parameter is the left-hand side of a [LIKE]
3234 ** or [GLOB] operator or if the parameter is compared to an indexed column
3235 ** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled.
3239 SQLITE_API int sqlite3_prepare(
3240 sqlite3 *db, /* Database handle */
3241 const char *zSql, /* SQL statement, UTF-8 encoded */
3242 int nByte, /* Maximum length of zSql in bytes. */
3243 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3244 const char **pzTail /* OUT: Pointer to unused portion of zSql */
3246 SQLITE_API int sqlite3_prepare_v2(
3247 sqlite3 *db, /* Database handle */
3248 const char *zSql, /* SQL statement, UTF-8 encoded */
3249 int nByte, /* Maximum length of zSql in bytes. */
3250 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3251 const char **pzTail /* OUT: Pointer to unused portion of zSql */
3253 SQLITE_API int sqlite3_prepare16(
3254 sqlite3 *db, /* Database handle */
3255 const void *zSql, /* SQL statement, UTF-16 encoded */
3256 int nByte, /* Maximum length of zSql in bytes. */
3257 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3258 const void **pzTail /* OUT: Pointer to unused portion of zSql */
3260 SQLITE_API int sqlite3_prepare16_v2(
3261 sqlite3 *db, /* Database handle */
3262 const void *zSql, /* SQL statement, UTF-16 encoded */
3263 int nByte, /* Maximum length of zSql in bytes. */
3264 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3265 const void **pzTail /* OUT: Pointer to unused portion of zSql */
3269 ** CAPI3REF: Retrieving Statement SQL
3271 ** ^This interface can be used to retrieve a saved copy of the original
3272 ** SQL text used to create a [prepared statement] if that statement was
3273 ** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()].
3275 SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt);
3278 ** CAPI3REF: Determine If An SQL Statement Writes The Database
3280 ** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
3281 ** and only if the [prepared statement] X makes no direct changes to
3282 ** the content of the database file.
3284 ** Note that [application-defined SQL functions] or
3285 ** [virtual tables] might change the database indirectly as a side effect.
3286 ** ^(For example, if an application defines a function "eval()" that
3287 ** calls [sqlite3_exec()], then the following SQL statement would
3288 ** change the database file through side-effects:
3290 ** <blockquote><pre>
3291 ** SELECT eval('DELETE FROM t1') FROM t2;
3292 ** </pre></blockquote>
3294 ** But because the [SELECT] statement does not change the database file
3295 ** directly, sqlite3_stmt_readonly() would still return true.)^
3297 ** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
3298 ** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
3299 ** since the statements themselves do not actually modify the database but
3300 ** rather they control the timing of when other statements modify the
3301 ** database. ^The [ATTACH] and [DETACH] statements also cause
3302 ** sqlite3_stmt_readonly() to return true since, while those statements
3303 ** change the configuration of a database connection, they do not make
3304 ** changes to the content of the database files on disk.
3306 SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
3309 ** CAPI3REF: Determine If A Prepared Statement Has Been Reset
3311 ** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
3312 ** [prepared statement] S has been stepped at least once using
3313 ** [sqlite3_step(S)] but has not run to completion and/or has not
3314 ** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S)
3315 ** interface returns false if S is a NULL pointer. If S is not a
3316 ** NULL pointer and is not a pointer to a valid [prepared statement]
3317 ** object, then the behavior is undefined and probably undesirable.
3319 ** This interface can be used in combination [sqlite3_next_stmt()]
3320 ** to locate all prepared statements associated with a database
3321 ** connection that are in need of being reset. This can be used,
3322 ** for example, in diagnostic routines to search for prepared
3323 ** statements that are holding a transaction open.
3325 SQLITE_API int sqlite3_stmt_busy(sqlite3_stmt*);
3328 ** CAPI3REF: Dynamically Typed Value Object
3329 ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
3331 ** SQLite uses the sqlite3_value object to represent all values
3332 ** that can be stored in a database table. SQLite uses dynamic typing
3333 ** for the values it stores. ^Values stored in sqlite3_value objects
3334 ** can be integers, floating point values, strings, BLOBs, or NULL.
3336 ** An sqlite3_value object may be either "protected" or "unprotected".
3337 ** Some interfaces require a protected sqlite3_value. Other interfaces
3338 ** will accept either a protected or an unprotected sqlite3_value.
3339 ** Every interface that accepts sqlite3_value arguments specifies
3340 ** whether or not it requires a protected sqlite3_value.
3342 ** The terms "protected" and "unprotected" refer to whether or not
3343 ** a mutex is held. An internal mutex is held for a protected
3344 ** sqlite3_value object but no mutex is held for an unprotected
3345 ** sqlite3_value object. If SQLite is compiled to be single-threaded
3346 ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
3347 ** or if SQLite is run in one of reduced mutex modes
3348 ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
3349 ** then there is no distinction between protected and unprotected
3350 ** sqlite3_value objects and they can be used interchangeably. However,
3351 ** for maximum code portability it is recommended that applications
3352 ** still make the distinction between protected and unprotected
3353 ** sqlite3_value objects even when not strictly required.
3355 ** ^The sqlite3_value objects that are passed as parameters into the
3356 ** implementation of [application-defined SQL functions] are protected.
3357 ** ^The sqlite3_value object returned by
3358 ** [sqlite3_column_value()] is unprotected.
3359 ** Unprotected sqlite3_value objects may only be used with
3360 ** [sqlite3_result_value()] and [sqlite3_bind_value()].
3361 ** The [sqlite3_value_blob | sqlite3_value_type()] family of
3362 ** interfaces require protected sqlite3_value objects.
3364 typedef struct Mem sqlite3_value;
3367 ** CAPI3REF: SQL Function Context Object
3369 ** The context in which an SQL function executes is stored in an
3370 ** sqlite3_context object. ^A pointer to an sqlite3_context object
3371 ** is always first parameter to [application-defined SQL functions].
3372 ** The application-defined SQL function implementation will pass this
3373 ** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
3374 ** [sqlite3_aggregate_context()], [sqlite3_user_data()],
3375 ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
3376 ** and/or [sqlite3_set_auxdata()].
3378 typedef struct sqlite3_context sqlite3_context;
3381 ** CAPI3REF: Binding Values To Prepared Statements
3382 ** KEYWORDS: {host parameter} {host parameters} {host parameter name}
3383 ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
3385 ** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
3386 ** literals may be replaced by a [parameter] that matches one of following
3397 ** In the templates above, NNN represents an integer literal,
3398 ** and VVV represents an alphanumeric identifier.)^ ^The values of these
3399 ** parameters (also called "host parameter names" or "SQL parameters")
3400 ** can be set using the sqlite3_bind_*() routines defined here.
3402 ** ^The first argument to the sqlite3_bind_*() routines is always
3403 ** a pointer to the [sqlite3_stmt] object returned from
3404 ** [sqlite3_prepare_v2()] or its variants.
3406 ** ^The second argument is the index of the SQL parameter to be set.
3407 ** ^The leftmost SQL parameter has an index of 1. ^When the same named
3408 ** SQL parameter is used more than once, second and subsequent
3409 ** occurrences have the same index as the first occurrence.
3410 ** ^The index for named parameters can be looked up using the
3411 ** [sqlite3_bind_parameter_index()] API if desired. ^The index
3412 ** for "?NNN" parameters is the value of NNN.
3413 ** ^The NNN value must be between 1 and the [sqlite3_limit()]
3414 ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999).
3416 ** ^The third argument is the value to bind to the parameter.
3417 ** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16()
3418 ** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter
3419 ** is ignored and the end result is the same as sqlite3_bind_null().
3421 ** ^(In those routines that have a fourth argument, its value is the
3422 ** number of bytes in the parameter. To be clear: the value is the
3423 ** number of <u>bytes</u> in the value, not the number of characters.)^
3424 ** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()
3425 ** is negative, then the length of the string is
3426 ** the number of bytes up to the first zero terminator.
3427 ** If the fourth parameter to sqlite3_bind_blob() is negative, then
3428 ** the behavior is undefined.
3429 ** If a non-negative fourth parameter is provided to sqlite3_bind_text()
3430 ** or sqlite3_bind_text16() or sqlite3_bind_text64() then
3431 ** that parameter must be the byte offset
3432 ** where the NUL terminator would occur assuming the string were NUL
3433 ** terminated. If any NUL characters occur at byte offsets less than
3434 ** the value of the fourth parameter then the resulting string value will
3435 ** contain embedded NULs. The result of expressions involving strings
3436 ** with embedded NULs is undefined.
3438 ** ^The fifth argument to the BLOB and string binding interfaces
3439 ** is a destructor used to dispose of the BLOB or
3440 ** string after SQLite has finished with it. ^The destructor is called
3441 ** to dispose of the BLOB or string even if the call to bind API fails.
3442 ** ^If the fifth argument is
3443 ** the special value [SQLITE_STATIC], then SQLite assumes that the
3444 ** information is in static, unmanaged space and does not need to be freed.
3445 ** ^If the fifth argument has the value [SQLITE_TRANSIENT], then
3446 ** SQLite makes its own private copy of the data immediately, before
3447 ** the sqlite3_bind_*() routine returns.
3449 ** ^The sixth argument to sqlite3_bind_text64() must be one of
3450 ** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]
3451 ** to specify the encoding of the text in the third parameter. If
3452 ** the sixth argument to sqlite3_bind_text64() is not one of the
3453 ** allowed values shown above, or if the text encoding is different
3454 ** from the encoding specified by the sixth parameter, then the behavior
3457 ** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
3458 ** is filled with zeroes. ^A zeroblob uses a fixed amount of memory
3459 ** (just an integer to hold its size) while it is being processed.
3460 ** Zeroblobs are intended to serve as placeholders for BLOBs whose
3461 ** content is later written using
3462 ** [sqlite3_blob_open | incremental BLOB I/O] routines.
3463 ** ^A negative value for the zeroblob results in a zero-length BLOB.
3465 ** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
3466 ** for the [prepared statement] or with a prepared statement for which
3467 ** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
3468 ** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_()
3469 ** routine is passed a [prepared statement] that has been finalized, the
3470 ** result is undefined and probably harmful.
3472 ** ^Bindings are not cleared by the [sqlite3_reset()] routine.
3473 ** ^Unbound parameters are interpreted as NULL.
3475 ** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
3476 ** [error code] if anything goes wrong.
3477 ** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB
3478 ** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or
3479 ** [SQLITE_MAX_LENGTH].
3480 ** ^[SQLITE_RANGE] is returned if the parameter
3481 ** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails.
3483 ** See also: [sqlite3_bind_parameter_count()],
3484 ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
3486 SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
3487 SQLITE_API int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64,
3489 SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double);
3490 SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int);
3491 SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
3492 SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int);
3493 SQLITE_API int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*));
3494 SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
3495 SQLITE_API int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64,
3496 void(*)(void*), unsigned char encoding);
3497 SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
3498 SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
3501 ** CAPI3REF: Number Of SQL Parameters
3503 ** ^This routine can be used to find the number of [SQL parameters]
3504 ** in a [prepared statement]. SQL parameters are tokens of the
3505 ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
3506 ** placeholders for values that are [sqlite3_bind_blob | bound]
3507 ** to the parameters at a later time.
3509 ** ^(This routine actually returns the index of the largest (rightmost)
3510 ** parameter. For all forms except ?NNN, this will correspond to the
3511 ** number of unique parameters. If parameters of the ?NNN form are used,
3512 ** there may be gaps in the list.)^
3514 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
3515 ** [sqlite3_bind_parameter_name()], and
3516 ** [sqlite3_bind_parameter_index()].
3518 SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*);
3521 ** CAPI3REF: Name Of A Host Parameter
3523 ** ^The sqlite3_bind_parameter_name(P,N) interface returns
3524 ** the name of the N-th [SQL parameter] in the [prepared statement] P.
3525 ** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
3526 ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
3528 ** In other words, the initial ":" or "$" or "@" or "?"
3529 ** is included as part of the name.)^
3530 ** ^Parameters of the form "?" without a following integer have no name
3531 ** and are referred to as "nameless" or "anonymous parameters".
3533 ** ^The first host parameter has an index of 1, not 0.
3535 ** ^If the value N is out of range or if the N-th parameter is
3536 ** nameless, then NULL is returned. ^The returned string is
3537 ** always in UTF-8 encoding even if the named parameter was
3538 ** originally specified as UTF-16 in [sqlite3_prepare16()] or
3539 ** [sqlite3_prepare16_v2()].
3541 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
3542 ** [sqlite3_bind_parameter_count()], and
3543 ** [sqlite3_bind_parameter_index()].
3545 SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
3548 ** CAPI3REF: Index Of A Parameter With A Given Name
3550 ** ^Return the index of an SQL parameter given its name. ^The
3551 ** index value returned is suitable for use as the second
3552 ** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero
3553 ** is returned if no matching parameter is found. ^The parameter
3554 ** name must be given in UTF-8 even if the original statement
3555 ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()].
3557 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
3558 ** [sqlite3_bind_parameter_count()], and
3559 ** [sqlite3_bind_parameter_index()].
3561 SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
3564 ** CAPI3REF: Reset All Bindings On A Prepared Statement
3566 ** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
3567 ** the [sqlite3_bind_blob | bindings] on a [prepared statement].
3568 ** ^Use this routine to reset all host parameters to NULL.
3570 SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*);
3573 ** CAPI3REF: Number Of Columns In A Result Set
3575 ** ^Return the number of columns in the result set returned by the
3576 ** [prepared statement]. ^This routine returns 0 if pStmt is an SQL
3577 ** statement that does not return data (for example an [UPDATE]).
3579 ** See also: [sqlite3_data_count()]
3581 SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt);
3584 ** CAPI3REF: Column Names In A Result Set
3586 ** ^These routines return the name assigned to a particular column
3587 ** in the result set of a [SELECT] statement. ^The sqlite3_column_name()
3588 ** interface returns a pointer to a zero-terminated UTF-8 string
3589 ** and sqlite3_column_name16() returns a pointer to a zero-terminated
3590 ** UTF-16 string. ^The first parameter is the [prepared statement]
3591 ** that implements the [SELECT] statement. ^The second parameter is the
3592 ** column number. ^The leftmost column is number 0.
3594 ** ^The returned string pointer is valid until either the [prepared statement]
3595 ** is destroyed by [sqlite3_finalize()] or until the statement is automatically
3596 ** reprepared by the first call to [sqlite3_step()] for a particular run
3597 ** or until the next call to
3598 ** sqlite3_column_name() or sqlite3_column_name16() on the same column.
3600 ** ^If sqlite3_malloc() fails during the processing of either routine
3601 ** (for example during a conversion from UTF-8 to UTF-16) then a
3602 ** NULL pointer is returned.
3604 ** ^The name of a result column is the value of the "AS" clause for
3605 ** that column, if there is an AS clause. If there is no AS clause
3606 ** then the name of the column is unspecified and may change from
3607 ** one release of SQLite to the next.
3609 SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N);
3610 SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N);
3613 ** CAPI3REF: Source Of Data In A Query Result
3615 ** ^These routines provide a means to determine the database, table, and
3616 ** table column that is the origin of a particular result column in
3617 ** [SELECT] statement.
3618 ** ^The name of the database or table or column can be returned as
3619 ** either a UTF-8 or UTF-16 string. ^The _database_ routines return
3620 ** the database name, the _table_ routines return the table name, and
3621 ** the origin_ routines return the column name.
3622 ** ^The returned string is valid until the [prepared statement] is destroyed
3623 ** using [sqlite3_finalize()] or until the statement is automatically
3624 ** reprepared by the first call to [sqlite3_step()] for a particular run
3625 ** or until the same information is requested
3626 ** again in a different encoding.
3628 ** ^The names returned are the original un-aliased names of the
3629 ** database, table, and column.
3631 ** ^The first argument to these interfaces is a [prepared statement].
3632 ** ^These functions return information about the Nth result column returned by
3633 ** the statement, where N is the second function argument.
3634 ** ^The left-most column is column 0 for these routines.
3636 ** ^If the Nth column returned by the statement is an expression or
3637 ** subquery and is not a column value, then all of these functions return
3638 ** NULL. ^These routine might also return NULL if a memory allocation error
3639 ** occurs. ^Otherwise, they return the name of the attached database, table,
3640 ** or column that query result column was extracted from.
3642 ** ^As with all other SQLite APIs, those whose names end with "16" return
3643 ** UTF-16 encoded strings and the other functions return UTF-8.
3645 ** ^These APIs are only available if the library was compiled with the
3646 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
3648 ** If two or more threads call one or more of these routines against the same
3649 ** prepared statement and column at the same time then the results are
3652 ** If two or more threads call one or more
3653 ** [sqlite3_column_database_name | column metadata interfaces]
3654 ** for the same [prepared statement] and result column
3655 ** at the same time then the results are undefined.
3657 SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int);
3658 SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
3659 SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int);
3660 SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
3661 SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
3662 SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
3665 ** CAPI3REF: Declared Datatype Of A Query Result
3667 ** ^(The first parameter is a [prepared statement].
3668 ** If this statement is a [SELECT] statement and the Nth column of the
3669 ** returned result set of that [SELECT] is a table column (not an
3670 ** expression or subquery) then the declared type of the table
3671 ** column is returned.)^ ^If the Nth column of the result set is an
3672 ** expression or subquery, then a NULL pointer is returned.
3673 ** ^The returned string is always UTF-8 encoded.
3675 ** ^(For example, given the database schema:
3677 ** CREATE TABLE t1(c1 VARIANT);
3679 ** and the following statement to be compiled:
3681 ** SELECT c1 + 1, c1 FROM t1;
3683 ** this routine would return the string "VARIANT" for the second result
3684 ** column (i==1), and a NULL pointer for the first result column (i==0).)^
3686 ** ^SQLite uses dynamic run-time typing. ^So just because a column
3687 ** is declared to contain a particular type does not mean that the
3688 ** data stored in that column is of the declared type. SQLite is
3689 ** strongly typed, but the typing is dynamic not static. ^Type
3690 ** is associated with individual values, not with the containers
3691 ** used to hold those values.
3693 SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int);
3694 SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
3697 ** CAPI3REF: Evaluate An SQL Statement
3699 ** After a [prepared statement] has been prepared using either
3700 ** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy
3701 ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
3702 ** must be called one or more times to evaluate the statement.
3704 ** The details of the behavior of the sqlite3_step() interface depend
3705 ** on whether the statement was prepared using the newer "v2" interface
3706 ** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy
3707 ** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the
3708 ** new "v2" interface is recommended for new applications but the legacy
3709 ** interface will continue to be supported.
3711 ** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
3712 ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
3713 ** ^With the "v2" interface, any of the other [result codes] or
3714 ** [extended result codes] might be returned as well.
3716 ** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
3717 ** database locks it needs to do its job. ^If the statement is a [COMMIT]
3718 ** or occurs outside of an explicit transaction, then you can retry the
3719 ** statement. If the statement is not a [COMMIT] and occurs within an
3720 ** explicit transaction then you should rollback the transaction before
3723 ** ^[SQLITE_DONE] means that the statement has finished executing
3724 ** successfully. sqlite3_step() should not be called again on this virtual
3725 ** machine without first calling [sqlite3_reset()] to reset the virtual
3726 ** machine back to its initial state.
3728 ** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
3729 ** is returned each time a new row of data is ready for processing by the
3730 ** caller. The values may be accessed using the [column access functions].
3731 ** sqlite3_step() is called again to retrieve the next row of data.
3733 ** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
3734 ** violation) has occurred. sqlite3_step() should not be called again on
3735 ** the VM. More information may be found by calling [sqlite3_errmsg()].
3736 ** ^With the legacy interface, a more specific error code (for example,
3737 ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
3738 ** can be obtained by calling [sqlite3_reset()] on the
3739 ** [prepared statement]. ^In the "v2" interface,
3740 ** the more specific error code is returned directly by sqlite3_step().
3742 ** [SQLITE_MISUSE] means that the this routine was called inappropriately.
3743 ** Perhaps it was called on a [prepared statement] that has
3744 ** already been [sqlite3_finalize | finalized] or on one that had
3745 ** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could
3746 ** be the case that the same database connection is being used by two or
3747 ** more threads at the same moment in time.
3749 ** For all versions of SQLite up to and including 3.6.23.1, a call to
3750 ** [sqlite3_reset()] was required after sqlite3_step() returned anything
3751 ** other than [SQLITE_ROW] before any subsequent invocation of
3752 ** sqlite3_step(). Failure to reset the prepared statement using
3753 ** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
3754 ** sqlite3_step(). But after version 3.6.23.1, sqlite3_step() began
3755 ** calling [sqlite3_reset()] automatically in this circumstance rather
3756 ** than returning [SQLITE_MISUSE]. This is not considered a compatibility
3757 ** break because any application that ever receives an SQLITE_MISUSE error
3758 ** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option
3759 ** can be used to restore the legacy behavior.
3761 ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
3762 ** API always returns a generic error code, [SQLITE_ERROR], following any
3763 ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call
3764 ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
3765 ** specific [error codes] that better describes the error.
3766 ** We admit that this is a goofy design. The problem has been fixed
3767 ** with the "v2" interface. If you prepare all of your SQL statements
3768 ** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead
3769 ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
3770 ** then the more specific [error codes] are returned directly
3771 ** by sqlite3_step(). The use of the "v2" interface is recommended.
3773 SQLITE_API int sqlite3_step(sqlite3_stmt*);
3776 ** CAPI3REF: Number of columns in a result set
3778 ** ^The sqlite3_data_count(P) interface returns the number of columns in the
3779 ** current row of the result set of [prepared statement] P.
3780 ** ^If prepared statement P does not have results ready to return
3781 ** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of
3782 ** interfaces) then sqlite3_data_count(P) returns 0.
3783 ** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
3784 ** ^The sqlite3_data_count(P) routine returns 0 if the previous call to
3785 ** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P)
3786 ** will return non-zero if previous call to [sqlite3_step](P) returned
3787 ** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum]
3788 ** where it always returns zero since each step of that multi-step
3789 ** pragma returns 0 columns of data.
3791 ** See also: [sqlite3_column_count()]
3793 SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
3796 ** CAPI3REF: Fundamental Datatypes
3797 ** KEYWORDS: SQLITE_TEXT
3799 ** ^(Every value in SQLite has one of five fundamental datatypes:
3802 ** <li> 64-bit signed integer
3803 ** <li> 64-bit IEEE floating point number
3809 ** These constants are codes for each of those types.
3811 ** Note that the SQLITE_TEXT constant was also used in SQLite version 2
3812 ** for a completely different meaning. Software that links against both
3813 ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
3816 #define SQLITE_INTEGER 1
3817 #define SQLITE_FLOAT 2
3818 #define SQLITE_BLOB 4
3819 #define SQLITE_NULL 5
3823 # define SQLITE_TEXT 3
3825 #define SQLITE3_TEXT 3
3828 ** CAPI3REF: Result Values From A Query
3829 ** KEYWORDS: {column access functions}
3831 ** These routines form the "result set" interface.
3833 ** ^These routines return information about a single column of the current
3834 ** result row of a query. ^In every case the first argument is a pointer
3835 ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
3836 ** that was returned from [sqlite3_prepare_v2()] or one of its variants)
3837 ** and the second argument is the index of the column for which information
3838 ** should be returned. ^The leftmost column of the result set has the index 0.
3839 ** ^The number of columns in the result can be determined using
3840 ** [sqlite3_column_count()].
3842 ** If the SQL statement does not currently point to a valid row, or if the
3843 ** column index is out of range, the result is undefined.
3844 ** These routines may only be called when the most recent call to
3845 ** [sqlite3_step()] has returned [SQLITE_ROW] and neither
3846 ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
3847 ** If any of these routines are called after [sqlite3_reset()] or
3848 ** [sqlite3_finalize()] or after [sqlite3_step()] has returned
3849 ** something other than [SQLITE_ROW], the results are undefined.
3850 ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
3851 ** are called from a different thread while any of these routines
3852 ** are pending, then the results are undefined.
3854 ** ^The sqlite3_column_type() routine returns the
3855 ** [SQLITE_INTEGER | datatype code] for the initial data type
3856 ** of the result column. ^The returned value is one of [SQLITE_INTEGER],
3857 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value
3858 ** returned by sqlite3_column_type() is only meaningful if no type
3859 ** conversions have occurred as described below. After a type conversion,
3860 ** the value returned by sqlite3_column_type() is undefined. Future
3861 ** versions of SQLite may change the behavior of sqlite3_column_type()
3862 ** following a type conversion.
3864 ** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
3865 ** routine returns the number of bytes in that BLOB or string.
3866 ** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
3867 ** the string to UTF-8 and then returns the number of bytes.
3868 ** ^If the result is a numeric value then sqlite3_column_bytes() uses
3869 ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
3870 ** the number of bytes in that string.
3871 ** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
3873 ** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
3874 ** routine returns the number of bytes in that BLOB or string.
3875 ** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
3876 ** the string to UTF-16 and then returns the number of bytes.
3877 ** ^If the result is a numeric value then sqlite3_column_bytes16() uses
3878 ** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
3879 ** the number of bytes in that string.
3880 ** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
3882 ** ^The values returned by [sqlite3_column_bytes()] and
3883 ** [sqlite3_column_bytes16()] do not include the zero terminators at the end
3884 ** of the string. ^For clarity: the values returned by
3885 ** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
3886 ** bytes in the string, not the number of characters.
3888 ** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
3889 ** even empty strings, are always zero-terminated. ^The return
3890 ** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
3892 ** ^The object returned by [sqlite3_column_value()] is an
3893 ** [unprotected sqlite3_value] object. An unprotected sqlite3_value object
3894 ** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()].
3895 ** If the [unprotected sqlite3_value] object returned by
3896 ** [sqlite3_column_value()] is used in any other way, including calls
3897 ** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
3898 ** or [sqlite3_value_bytes()], then the behavior is undefined.
3900 ** These routines attempt to convert the value where appropriate. ^For
3901 ** example, if the internal representation is FLOAT and a text result
3902 ** is requested, [sqlite3_snprintf()] is used internally to perform the
3903 ** conversion automatically. ^(The following table details the conversions
3904 ** that are applied:
3907 ** <table border="1">
3908 ** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion
3910 ** <tr><td> NULL <td> INTEGER <td> Result is 0
3911 ** <tr><td> NULL <td> FLOAT <td> Result is 0.0
3912 ** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer
3913 ** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer
3914 ** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float
3915 ** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer
3916 ** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT
3917 ** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER
3918 ** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float
3919 ** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB
3920 ** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER
3921 ** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL
3922 ** <tr><td> TEXT <td> BLOB <td> No change
3923 ** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER
3924 ** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL
3925 ** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed
3929 ** The table above makes reference to standard C library functions atoi()
3930 ** and atof(). SQLite does not really use these functions. It has its
3931 ** own equivalent internal routines. The atoi() and atof() names are
3932 ** used in the table for brevity and because they are familiar to most
3935 ** Note that when type conversions occur, pointers returned by prior
3936 ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
3937 ** sqlite3_column_text16() may be invalidated.
3938 ** Type conversions and pointer invalidations might occur
3939 ** in the following cases:
3942 ** <li> The initial content is a BLOB and sqlite3_column_text() or
3943 ** sqlite3_column_text16() is called. A zero-terminator might
3944 ** need to be added to the string.</li>
3945 ** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
3946 ** sqlite3_column_text16() is called. The content must be converted
3948 ** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
3949 ** sqlite3_column_text() is called. The content must be converted
3953 ** ^Conversions between UTF-16be and UTF-16le are always done in place and do
3954 ** not invalidate a prior pointer, though of course the content of the buffer
3955 ** that the prior pointer references will have been modified. Other kinds
3956 ** of conversion are done in place when it is possible, but sometimes they
3957 ** are not possible and in those cases prior pointers are invalidated.
3959 ** The safest and easiest to remember policy is to invoke these routines
3960 ** in one of the following ways:
3963 ** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
3964 ** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
3965 ** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
3968 ** In other words, you should call sqlite3_column_text(),
3969 ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
3970 ** into the desired format, then invoke sqlite3_column_bytes() or
3971 ** sqlite3_column_bytes16() to find the size of the result. Do not mix calls
3972 ** to sqlite3_column_text() or sqlite3_column_blob() with calls to
3973 ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
3974 ** with calls to sqlite3_column_bytes().
3976 ** ^The pointers returned are valid until a type conversion occurs as
3977 ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
3978 ** [sqlite3_finalize()] is called. ^The memory space used to hold strings
3979 ** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned
3980 ** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
3981 ** [sqlite3_free()].
3983 ** ^(If a memory allocation error occurs during the evaluation of any
3984 ** of these routines, a default value is returned. The default value
3985 ** is either the integer 0, the floating point number 0.0, or a NULL
3986 ** pointer. Subsequent calls to [sqlite3_errcode()] will return
3987 ** [SQLITE_NOMEM].)^
3989 SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
3990 SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
3991 SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
3992 SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol);
3993 SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol);
3994 SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
3995 SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
3996 SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
3997 SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol);
3998 SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
4001 ** CAPI3REF: Destroy A Prepared Statement Object
4003 ** ^The sqlite3_finalize() function is called to delete a [prepared statement].
4004 ** ^If the most recent evaluation of the statement encountered no errors
4005 ** or if the statement is never been evaluated, then sqlite3_finalize() returns
4006 ** SQLITE_OK. ^If the most recent evaluation of statement S failed, then
4007 ** sqlite3_finalize(S) returns the appropriate [error code] or
4008 ** [extended error code].
4010 ** ^The sqlite3_finalize(S) routine can be called at any point during
4011 ** the life cycle of [prepared statement] S:
4012 ** before statement S is ever evaluated, after
4013 ** one or more calls to [sqlite3_reset()], or after any call
4014 ** to [sqlite3_step()] regardless of whether or not the statement has
4015 ** completed execution.
4017 ** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
4019 ** The application must finalize every [prepared statement] in order to avoid
4020 ** resource leaks. It is a grievous error for the application to try to use
4021 ** a prepared statement after it has been finalized. Any use of a prepared
4022 ** statement after it has been finalized can result in undefined and
4023 ** undesirable behavior such as segfaults and heap corruption.
4025 SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt);
4028 ** CAPI3REF: Reset A Prepared Statement Object
4030 ** The sqlite3_reset() function is called to reset a [prepared statement]
4031 ** object back to its initial state, ready to be re-executed.
4032 ** ^Any SQL statement variables that had values bound to them using
4033 ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
4034 ** Use [sqlite3_clear_bindings()] to reset the bindings.
4036 ** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
4037 ** back to the beginning of its program.
4039 ** ^If the most recent call to [sqlite3_step(S)] for the
4040 ** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
4041 ** or if [sqlite3_step(S)] has never before been called on S,
4042 ** then [sqlite3_reset(S)] returns [SQLITE_OK].
4044 ** ^If the most recent call to [sqlite3_step(S)] for the
4045 ** [prepared statement] S indicated an error, then
4046 ** [sqlite3_reset(S)] returns an appropriate [error code].
4048 ** ^The [sqlite3_reset(S)] interface does not change the values
4049 ** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
4051 SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt);
4054 ** CAPI3REF: Create Or Redefine SQL Functions
4055 ** KEYWORDS: {function creation routines}
4056 ** KEYWORDS: {application-defined SQL function}
4057 ** KEYWORDS: {application-defined SQL functions}
4059 ** ^These functions (collectively known as "function creation routines")
4060 ** are used to add SQL functions or aggregates or to redefine the behavior
4061 ** of existing SQL functions or aggregates. The only differences between
4062 ** these routines are the text encoding expected for
4063 ** the second parameter (the name of the function being created)
4064 ** and the presence or absence of a destructor callback for
4065 ** the application data pointer.
4067 ** ^The first parameter is the [database connection] to which the SQL
4068 ** function is to be added. ^If an application uses more than one database
4069 ** connection then application-defined SQL functions must be added
4070 ** to each database connection separately.
4072 ** ^The second parameter is the name of the SQL function to be created or
4073 ** redefined. ^The length of the name is limited to 255 bytes in a UTF-8
4074 ** representation, exclusive of the zero-terminator. ^Note that the name
4075 ** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
4076 ** ^Any attempt to create a function with a longer name
4077 ** will result in [SQLITE_MISUSE] being returned.
4079 ** ^The third parameter (nArg)
4080 ** is the number of arguments that the SQL function or
4081 ** aggregate takes. ^If this parameter is -1, then the SQL function or
4082 ** aggregate may take any number of arguments between 0 and the limit
4083 ** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third
4084 ** parameter is less than -1 or greater than 127 then the behavior is
4087 ** ^The fourth parameter, eTextRep, specifies what
4088 ** [SQLITE_UTF8 | text encoding] this SQL function prefers for
4089 ** its parameters. The application should set this parameter to
4090 ** [SQLITE_UTF16LE] if the function implementation invokes
4091 ** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the
4092 ** implementation invokes [sqlite3_value_text16be()] on an input, or
4093 ** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8]
4094 ** otherwise. ^The same SQL function may be registered multiple times using
4095 ** different preferred text encodings, with different implementations for
4097 ** ^When multiple implementations of the same function are available, SQLite
4098 ** will pick the one that involves the least amount of data conversion.
4100 ** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC]
4101 ** to signal that the function will always return the same result given
4102 ** the same inputs within a single SQL statement. Most SQL functions are
4103 ** deterministic. The built-in [random()] SQL function is an example of a
4104 ** function that is not deterministic. The SQLite query planner is able to
4105 ** perform additional optimizations on deterministic functions, so use
4106 ** of the [SQLITE_DETERMINISTIC] flag is recommended where possible.
4108 ** ^(The fifth parameter is an arbitrary pointer. The implementation of the
4109 ** function can gain access to this pointer using [sqlite3_user_data()].)^
4111 ** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are
4112 ** pointers to C-language functions that implement the SQL function or
4113 ** aggregate. ^A scalar SQL function requires an implementation of the xFunc
4114 ** callback only; NULL pointers must be passed as the xStep and xFinal
4115 ** parameters. ^An aggregate SQL function requires an implementation of xStep
4116 ** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
4117 ** SQL function or aggregate, pass NULL pointers for all three function
4120 ** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL,
4121 ** then it is destructor for the application data pointer.
4122 ** The destructor is invoked when the function is deleted, either by being
4123 ** overloaded or when the database connection closes.)^
4124 ** ^The destructor is also invoked if the call to
4125 ** sqlite3_create_function_v2() fails.
4126 ** ^When the destructor callback of the tenth parameter is invoked, it
4127 ** is passed a single argument which is a copy of the application data
4128 ** pointer which was the fifth parameter to sqlite3_create_function_v2().
4130 ** ^It is permitted to register multiple implementations of the same
4131 ** functions with the same name but with either differing numbers of
4132 ** arguments or differing preferred text encodings. ^SQLite will use
4133 ** the implementation that most closely matches the way in which the
4134 ** SQL function is used. ^A function implementation with a non-negative
4135 ** nArg parameter is a better match than a function implementation with
4136 ** a negative nArg. ^A function where the preferred text encoding
4137 ** matches the database encoding is a better
4138 ** match than a function where the encoding is different.
4139 ** ^A function where the encoding difference is between UTF16le and UTF16be
4140 ** is a closer match than a function where the encoding difference is
4141 ** between UTF8 and UTF16.
4143 ** ^Built-in functions may be overloaded by new application-defined functions.
4145 ** ^An application-defined function is permitted to call other
4146 ** SQLite interfaces. However, such calls must not
4147 ** close the database connection nor finalize or reset the prepared
4148 ** statement in which the function is running.
4150 SQLITE_API int sqlite3_create_function(
4152 const char *zFunctionName,
4156 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4157 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4158 void (*xFinal)(sqlite3_context*)
4160 SQLITE_API int sqlite3_create_function16(
4162 const void *zFunctionName,
4166 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4167 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4168 void (*xFinal)(sqlite3_context*)
4170 SQLITE_API int sqlite3_create_function_v2(
4172 const char *zFunctionName,
4176 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4177 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4178 void (*xFinal)(sqlite3_context*),
4179 void(*xDestroy)(void*)
4183 ** CAPI3REF: Text Encodings
4185 ** These constant define integer codes that represent the various
4186 ** text encodings supported by SQLite.
4188 #define SQLITE_UTF8 1 /* IMP: R-37514-35566 */
4189 #define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */
4190 #define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */
4191 #define SQLITE_UTF16 4 /* Use native byte order */
4192 #define SQLITE_ANY 5 /* Deprecated */
4193 #define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */
4196 ** CAPI3REF: Function Flags
4198 ** These constants may be ORed together with the
4199 ** [SQLITE_UTF8 | preferred text encoding] as the fourth argument
4200 ** to [sqlite3_create_function()], [sqlite3_create_function16()], or
4201 ** [sqlite3_create_function_v2()].
4203 #define SQLITE_DETERMINISTIC 0x800
4206 ** CAPI3REF: Deprecated Functions
4209 ** These functions are [deprecated]. In order to maintain
4210 ** backwards compatibility with older code, these functions continue
4211 ** to be supported. However, new applications should avoid
4212 ** the use of these functions. To help encourage people to avoid
4213 ** using these functions, we are not going to tell you what they do.
4215 #ifndef SQLITE_OMIT_DEPRECATED
4216 SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
4217 SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
4218 SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
4219 SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void);
4220 SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
4221 SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),
4222 void*,sqlite3_int64);
4226 ** CAPI3REF: Obtaining SQL Function Parameter Values
4228 ** The C-language implementation of SQL functions and aggregates uses
4229 ** this set of interface routines to access the parameter values on
4230 ** the function or aggregate.
4232 ** The xFunc (for scalar functions) or xStep (for aggregates) parameters
4233 ** to [sqlite3_create_function()] and [sqlite3_create_function16()]
4234 ** define callbacks that implement the SQL functions and aggregates.
4235 ** The 3rd parameter to these callbacks is an array of pointers to
4236 ** [protected sqlite3_value] objects. There is one [sqlite3_value] object for
4237 ** each parameter to the SQL function. These routines are used to
4238 ** extract values from the [sqlite3_value] objects.
4240 ** These routines work only with [protected sqlite3_value] objects.
4241 ** Any attempt to use these routines on an [unprotected sqlite3_value]
4242 ** object results in undefined behavior.
4244 ** ^These routines work just like the corresponding [column access functions]
4245 ** except that these routines take a single [protected sqlite3_value] object
4246 ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
4248 ** ^The sqlite3_value_text16() interface extracts a UTF-16 string
4249 ** in the native byte-order of the host machine. ^The
4250 ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
4251 ** extract UTF-16 strings as big-endian and little-endian respectively.
4253 ** ^(The sqlite3_value_numeric_type() interface attempts to apply
4254 ** numeric affinity to the value. This means that an attempt is
4255 ** made to convert the value to an integer or floating point. If
4256 ** such a conversion is possible without loss of information (in other
4257 ** words, if the value is a string that looks like a number)
4258 ** then the conversion is performed. Otherwise no conversion occurs.
4259 ** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
4261 ** Please pay particular attention to the fact that the pointer returned
4262 ** from [sqlite3_value_blob()], [sqlite3_value_text()], or
4263 ** [sqlite3_value_text16()] can be invalidated by a subsequent call to
4264 ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
4265 ** or [sqlite3_value_text16()].
4267 ** These routines must be called from the same thread as
4268 ** the SQL function that supplied the [sqlite3_value*] parameters.
4270 SQLITE_API const void *sqlite3_value_blob(sqlite3_value*);
4271 SQLITE_API int sqlite3_value_bytes(sqlite3_value*);
4272 SQLITE_API int sqlite3_value_bytes16(sqlite3_value*);
4273 SQLITE_API double sqlite3_value_double(sqlite3_value*);
4274 SQLITE_API int sqlite3_value_int(sqlite3_value*);
4275 SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
4276 SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*);
4277 SQLITE_API const void *sqlite3_value_text16(sqlite3_value*);
4278 SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*);
4279 SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*);
4280 SQLITE_API int sqlite3_value_type(sqlite3_value*);
4281 SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*);
4284 ** CAPI3REF: Obtain Aggregate Function Context
4286 ** Implementations of aggregate SQL functions use this
4287 ** routine to allocate memory for storing their state.
4289 ** ^The first time the sqlite3_aggregate_context(C,N) routine is called
4290 ** for a particular aggregate function, SQLite
4291 ** allocates N of memory, zeroes out that memory, and returns a pointer
4292 ** to the new memory. ^On second and subsequent calls to
4293 ** sqlite3_aggregate_context() for the same aggregate function instance,
4294 ** the same buffer is returned. Sqlite3_aggregate_context() is normally
4295 ** called once for each invocation of the xStep callback and then one
4296 ** last time when the xFinal callback is invoked. ^(When no rows match
4297 ** an aggregate query, the xStep() callback of the aggregate function
4298 ** implementation is never called and xFinal() is called exactly once.
4299 ** In those cases, sqlite3_aggregate_context() might be called for the
4300 ** first time from within xFinal().)^
4302 ** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer
4303 ** when first called if N is less than or equal to zero or if a memory
4304 ** allocate error occurs.
4306 ** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
4307 ** determined by the N parameter on first successful call. Changing the
4308 ** value of N in subsequent call to sqlite3_aggregate_context() within
4309 ** the same aggregate function instance will not resize the memory
4310 ** allocation.)^ Within the xFinal callback, it is customary to set
4311 ** N=0 in calls to sqlite3_aggregate_context(C,N) so that no
4312 ** pointless memory allocations occur.
4314 ** ^SQLite automatically frees the memory allocated by
4315 ** sqlite3_aggregate_context() when the aggregate query concludes.
4317 ** The first parameter must be a copy of the
4318 ** [sqlite3_context | SQL function context] that is the first parameter
4319 ** to the xStep or xFinal callback routine that implements the aggregate
4322 ** This routine must be called from the same thread in which
4323 ** the aggregate SQL function is running.
4325 SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
4328 ** CAPI3REF: User Data For Functions
4330 ** ^The sqlite3_user_data() interface returns a copy of
4331 ** the pointer that was the pUserData parameter (the 5th parameter)
4332 ** of the [sqlite3_create_function()]
4333 ** and [sqlite3_create_function16()] routines that originally
4334 ** registered the application defined function.
4336 ** This routine must be called from the same thread in which
4337 ** the application-defined function is running.
4339 SQLITE_API void *sqlite3_user_data(sqlite3_context*);
4342 ** CAPI3REF: Database Connection For Functions
4344 ** ^The sqlite3_context_db_handle() interface returns a copy of
4345 ** the pointer to the [database connection] (the 1st parameter)
4346 ** of the [sqlite3_create_function()]
4347 ** and [sqlite3_create_function16()] routines that originally
4348 ** registered the application defined function.
4350 SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
4353 ** CAPI3REF: Function Auxiliary Data
4355 ** These functions may be used by (non-aggregate) SQL functions to
4356 ** associate metadata with argument values. If the same value is passed to
4357 ** multiple invocations of the same SQL function during query execution, under
4358 ** some circumstances the associated metadata may be preserved. An example
4359 ** of where this might be useful is in a regular-expression matching
4360 ** function. The compiled version of the regular expression can be stored as
4361 ** metadata associated with the pattern string.
4362 ** Then as long as the pattern string remains the same,
4363 ** the compiled regular expression can be reused on multiple
4364 ** invocations of the same function.
4366 ** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata
4367 ** associated by the sqlite3_set_auxdata() function with the Nth argument
4368 ** value to the application-defined function. ^If there is no metadata
4369 ** associated with the function argument, this sqlite3_get_auxdata() interface
4370 ** returns a NULL pointer.
4372 ** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th
4373 ** argument of the application-defined function. ^Subsequent
4374 ** calls to sqlite3_get_auxdata(C,N) return P from the most recent
4375 ** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or
4376 ** NULL if the metadata has been discarded.
4377 ** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL,
4378 ** SQLite will invoke the destructor function X with parameter P exactly
4379 ** once, when the metadata is discarded.
4380 ** SQLite is free to discard the metadata at any time, including: <ul>
4381 ** <li> when the corresponding function parameter changes, or
4382 ** <li> when [sqlite3_reset()] or [sqlite3_finalize()] is called for the
4383 ** SQL statement, or
4384 ** <li> when sqlite3_set_auxdata() is invoked again on the same parameter, or
4385 ** <li> during the original sqlite3_set_auxdata() call when a memory
4386 ** allocation error occurs. </ul>)^
4388 ** Note the last bullet in particular. The destructor X in
4389 ** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the
4390 ** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata()
4391 ** should be called near the end of the function implementation and the
4392 ** function implementation should not make any use of P after
4393 ** sqlite3_set_auxdata() has been called.
4395 ** ^(In practice, metadata is preserved between function calls for
4396 ** function parameters that are compile-time constants, including literal
4397 ** values and [parameters] and expressions composed from the same.)^
4399 ** These routines must be called from the same thread in which
4400 ** the SQL function is running.
4402 SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N);
4403 SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
4407 ** CAPI3REF: Constants Defining Special Destructor Behavior
4409 ** These are special values for the destructor that is passed in as the
4410 ** final argument to routines like [sqlite3_result_blob()]. ^If the destructor
4411 ** argument is SQLITE_STATIC, it means that the content pointer is constant
4412 ** and will never change. It does not need to be destroyed. ^The
4413 ** SQLITE_TRANSIENT value means that the content will likely change in
4414 ** the near future and that SQLite should make its own private copy of
4415 ** the content before returning.
4417 ** The typedef is necessary to work around problems in certain
4420 typedef void (*sqlite3_destructor_type)(void*);
4421 #define SQLITE_STATIC ((sqlite3_destructor_type)0)
4422 #define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1)
4425 ** CAPI3REF: Setting The Result Of An SQL Function
4427 ** These routines are used by the xFunc or xFinal callbacks that
4428 ** implement SQL functions and aggregates. See
4429 ** [sqlite3_create_function()] and [sqlite3_create_function16()]
4430 ** for additional information.
4432 ** These functions work very much like the [parameter binding] family of
4433 ** functions used to bind values to host parameters in prepared statements.
4434 ** Refer to the [SQL parameter] documentation for additional information.
4436 ** ^The sqlite3_result_blob() interface sets the result from
4437 ** an application-defined function to be the BLOB whose content is pointed
4438 ** to by the second parameter and which is N bytes long where N is the
4441 ** ^The sqlite3_result_zeroblob() interfaces set the result of
4442 ** the application-defined function to be a BLOB containing all zero
4443 ** bytes and N bytes in size, where N is the value of the 2nd parameter.
4445 ** ^The sqlite3_result_double() interface sets the result from
4446 ** an application-defined function to be a floating point value specified
4447 ** by its 2nd argument.
4449 ** ^The sqlite3_result_error() and sqlite3_result_error16() functions
4450 ** cause the implemented SQL function to throw an exception.
4451 ** ^SQLite uses the string pointed to by the
4452 ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
4453 ** as the text of an error message. ^SQLite interprets the error
4454 ** message string from sqlite3_result_error() as UTF-8. ^SQLite
4455 ** interprets the string from sqlite3_result_error16() as UTF-16 in native
4456 ** byte order. ^If the third parameter to sqlite3_result_error()
4457 ** or sqlite3_result_error16() is negative then SQLite takes as the error
4458 ** message all text up through the first zero character.
4459 ** ^If the third parameter to sqlite3_result_error() or
4460 ** sqlite3_result_error16() is non-negative then SQLite takes that many
4461 ** bytes (not characters) from the 2nd parameter as the error message.
4462 ** ^The sqlite3_result_error() and sqlite3_result_error16()
4463 ** routines make a private copy of the error message text before
4464 ** they return. Hence, the calling function can deallocate or
4465 ** modify the text after they return without harm.
4466 ** ^The sqlite3_result_error_code() function changes the error code
4467 ** returned by SQLite as a result of an error in a function. ^By default,
4468 ** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error()
4469 ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
4471 ** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an
4472 ** error indicating that a string or BLOB is too long to represent.
4474 ** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an
4475 ** error indicating that a memory allocation failed.
4477 ** ^The sqlite3_result_int() interface sets the return value
4478 ** of the application-defined function to be the 32-bit signed integer
4479 ** value given in the 2nd argument.
4480 ** ^The sqlite3_result_int64() interface sets the return value
4481 ** of the application-defined function to be the 64-bit signed integer
4482 ** value given in the 2nd argument.
4484 ** ^The sqlite3_result_null() interface sets the return value
4485 ** of the application-defined function to be NULL.
4487 ** ^The sqlite3_result_text(), sqlite3_result_text16(),
4488 ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
4489 ** set the return value of the application-defined function to be
4490 ** a text string which is represented as UTF-8, UTF-16 native byte order,
4491 ** UTF-16 little endian, or UTF-16 big endian, respectively.
4492 ** ^The sqlite3_result_text64() interface sets the return value of an
4493 ** application-defined function to be a text string in an encoding
4494 ** specified by the fifth (and last) parameter, which must be one
4495 ** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE].
4496 ** ^SQLite takes the text result from the application from
4497 ** the 2nd parameter of the sqlite3_result_text* interfaces.
4498 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
4499 ** is negative, then SQLite takes result text from the 2nd parameter
4500 ** through the first zero character.
4501 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
4502 ** is non-negative, then as many bytes (not characters) of the text
4503 ** pointed to by the 2nd parameter are taken as the application-defined
4504 ** function result. If the 3rd parameter is non-negative, then it
4505 ** must be the byte offset into the string where the NUL terminator would
4506 ** appear if the string where NUL terminated. If any NUL characters occur
4507 ** in the string at a byte offset that is less than the value of the 3rd
4508 ** parameter, then the resulting string will contain embedded NULs and the
4509 ** result of expressions operating on strings with embedded NULs is undefined.
4510 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
4511 ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
4512 ** function as the destructor on the text or BLOB result when it has
4513 ** finished using that result.
4514 ** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
4515 ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
4516 ** assumes that the text or BLOB result is in constant space and does not
4517 ** copy the content of the parameter nor call a destructor on the content
4518 ** when it has finished using that result.
4519 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
4520 ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
4521 ** then SQLite makes a copy of the result into space obtained from
4522 ** from [sqlite3_malloc()] before it returns.
4524 ** ^The sqlite3_result_value() interface sets the result of
4525 ** the application-defined function to be a copy the
4526 ** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The
4527 ** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
4528 ** so that the [sqlite3_value] specified in the parameter may change or
4529 ** be deallocated after sqlite3_result_value() returns without harm.
4530 ** ^A [protected sqlite3_value] object may always be used where an
4531 ** [unprotected sqlite3_value] object is required, so either
4532 ** kind of [sqlite3_value] object can be used with this interface.
4534 ** If these routines are called from within the different thread
4535 ** than the one containing the application-defined function that received
4536 ** the [sqlite3_context] pointer, the results are undefined.
4538 SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
4539 SQLITE_API void sqlite3_result_blob64(sqlite3_context*,const void*,
4540 sqlite3_uint64,void(*)(void*));
4541 SQLITE_API void sqlite3_result_double(sqlite3_context*, double);
4542 SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int);
4543 SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int);
4544 SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*);
4545 SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*);
4546 SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int);
4547 SQLITE_API void sqlite3_result_int(sqlite3_context*, int);
4548 SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
4549 SQLITE_API void sqlite3_result_null(sqlite3_context*);
4550 SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
4551 SQLITE_API void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64,
4552 void(*)(void*), unsigned char encoding);
4553 SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
4554 SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
4555 SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
4556 SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
4557 SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n);
4560 ** CAPI3REF: Define New Collating Sequences
4562 ** ^These functions add, remove, or modify a [collation] associated
4563 ** with the [database connection] specified as the first argument.
4565 ** ^The name of the collation is a UTF-8 string
4566 ** for sqlite3_create_collation() and sqlite3_create_collation_v2()
4567 ** and a UTF-16 string in native byte order for sqlite3_create_collation16().
4568 ** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
4569 ** considered to be the same name.
4571 ** ^(The third argument (eTextRep) must be one of the constants:
4573 ** <li> [SQLITE_UTF8],
4574 ** <li> [SQLITE_UTF16LE],
4575 ** <li> [SQLITE_UTF16BE],
4576 ** <li> [SQLITE_UTF16], or
4577 ** <li> [SQLITE_UTF16_ALIGNED].
4579 ** ^The eTextRep argument determines the encoding of strings passed
4580 ** to the collating function callback, xCallback.
4581 ** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
4582 ** force strings to be UTF16 with native byte order.
4583 ** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
4584 ** on an even byte address.
4586 ** ^The fourth argument, pArg, is an application data pointer that is passed
4587 ** through as the first argument to the collating function callback.
4589 ** ^The fifth argument, xCallback, is a pointer to the collating function.
4590 ** ^Multiple collating functions can be registered using the same name but
4591 ** with different eTextRep parameters and SQLite will use whichever
4592 ** function requires the least amount of data transformation.
4593 ** ^If the xCallback argument is NULL then the collating function is
4594 ** deleted. ^When all collating functions having the same name are deleted,
4595 ** that collation is no longer usable.
4597 ** ^The collating function callback is invoked with a copy of the pArg
4598 ** application data pointer and with two strings in the encoding specified
4599 ** by the eTextRep argument. The collating function must return an
4600 ** integer that is negative, zero, or positive
4601 ** if the first string is less than, equal to, or greater than the second,
4602 ** respectively. A collating function must always return the same answer
4603 ** given the same inputs. If two or more collating functions are registered
4604 ** to the same collation name (using different eTextRep values) then all
4605 ** must give an equivalent answer when invoked with equivalent strings.
4606 ** The collating function must obey the following properties for all
4607 ** strings A, B, and C:
4610 ** <li> If A==B then B==A.
4611 ** <li> If A==B and B==C then A==C.
4612 ** <li> If A<B THEN B>A.
4613 ** <li> If A<B and B<C then A<C.
4616 ** If a collating function fails any of the above constraints and that
4617 ** collating function is registered and used, then the behavior of SQLite
4620 ** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
4621 ** with the addition that the xDestroy callback is invoked on pArg when
4622 ** the collating function is deleted.
4623 ** ^Collating functions are deleted when they are overridden by later
4624 ** calls to the collation creation functions or when the
4625 ** [database connection] is closed using [sqlite3_close()].
4627 ** ^The xDestroy callback is <u>not</u> called if the
4628 ** sqlite3_create_collation_v2() function fails. Applications that invoke
4629 ** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
4630 ** check the return code and dispose of the application data pointer
4631 ** themselves rather than expecting SQLite to deal with it for them.
4632 ** This is different from every other SQLite interface. The inconsistency
4633 ** is unfortunate but cannot be changed without breaking backwards
4636 ** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
4638 SQLITE_API int sqlite3_create_collation(
4643 int(*xCompare)(void*,int,const void*,int,const void*)
4645 SQLITE_API int sqlite3_create_collation_v2(
4650 int(*xCompare)(void*,int,const void*,int,const void*),
4651 void(*xDestroy)(void*)
4653 SQLITE_API int sqlite3_create_collation16(
4658 int(*xCompare)(void*,int,const void*,int,const void*)
4662 ** CAPI3REF: Collation Needed Callbacks
4664 ** ^To avoid having to register all collation sequences before a database
4665 ** can be used, a single callback function may be registered with the
4666 ** [database connection] to be invoked whenever an undefined collation
4667 ** sequence is required.
4669 ** ^If the function is registered using the sqlite3_collation_needed() API,
4670 ** then it is passed the names of undefined collation sequences as strings
4671 ** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
4672 ** the names are passed as UTF-16 in machine native byte order.
4673 ** ^A call to either function replaces the existing collation-needed callback.
4675 ** ^(When the callback is invoked, the first argument passed is a copy
4676 ** of the second argument to sqlite3_collation_needed() or
4677 ** sqlite3_collation_needed16(). The second argument is the database
4678 ** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
4679 ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
4680 ** sequence function required. The fourth parameter is the name of the
4681 ** required collation sequence.)^
4683 ** The callback function should register the desired collation using
4684 ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
4685 ** [sqlite3_create_collation_v2()].
4687 SQLITE_API int sqlite3_collation_needed(
4690 void(*)(void*,sqlite3*,int eTextRep,const char*)
4692 SQLITE_API int sqlite3_collation_needed16(
4695 void(*)(void*,sqlite3*,int eTextRep,const void*)
4698 #ifdef SQLITE_HAS_CODEC
4700 ** Specify the key for an encrypted database. This routine should be
4701 ** called right after sqlite3_open().
4703 ** The code to implement this API is not available in the public release
4706 SQLITE_API int sqlite3_key(
4707 sqlite3 *db, /* Database to be rekeyed */
4708 const void *pKey, int nKey /* The key */
4710 SQLITE_API int sqlite3_key_v2(
4711 sqlite3 *db, /* Database to be rekeyed */
4712 const char *zDbName, /* Name of the database */
4713 const void *pKey, int nKey /* The key */
4717 ** Change the key on an open database. If the current database is not
4718 ** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the
4719 ** database is decrypted.
4721 ** The code to implement this API is not available in the public release
4724 SQLITE_API int sqlite3_rekey(
4725 sqlite3 *db, /* Database to be rekeyed */
4726 const void *pKey, int nKey /* The new key */
4728 SQLITE_API int sqlite3_rekey_v2(
4729 sqlite3 *db, /* Database to be rekeyed */
4730 const char *zDbName, /* Name of the database */
4731 const void *pKey, int nKey /* The new key */
4735 ** Specify the activation key for a SEE database. Unless
4736 ** activated, none of the SEE routines will work.
4738 SQLITE_API void sqlite3_activate_see(
4739 const char *zPassPhrase /* Activation phrase */
4743 #ifdef SQLITE_ENABLE_CEROD
4745 ** Specify the activation key for a CEROD database. Unless
4746 ** activated, none of the CEROD routines will work.
4748 SQLITE_API void sqlite3_activate_cerod(
4749 const char *zPassPhrase /* Activation phrase */
4754 ** CAPI3REF: Suspend Execution For A Short Time
4756 ** The sqlite3_sleep() function causes the current thread to suspend execution
4757 ** for at least a number of milliseconds specified in its parameter.
4759 ** If the operating system does not support sleep requests with
4760 ** millisecond time resolution, then the time will be rounded up to
4761 ** the nearest second. The number of milliseconds of sleep actually
4762 ** requested from the operating system is returned.
4764 ** ^SQLite implements this interface by calling the xSleep()
4765 ** method of the default [sqlite3_vfs] object. If the xSleep() method
4766 ** of the default VFS is not implemented correctly, or not implemented at
4767 ** all, then the behavior of sqlite3_sleep() may deviate from the description
4768 ** in the previous paragraphs.
4770 SQLITE_API int sqlite3_sleep(int);
4773 ** CAPI3REF: Name Of The Folder Holding Temporary Files
4775 ** ^(If this global variable is made to point to a string which is
4776 ** the name of a folder (a.k.a. directory), then all temporary files
4777 ** created by SQLite when using a built-in [sqlite3_vfs | VFS]
4778 ** will be placed in that directory.)^ ^If this variable
4779 ** is a NULL pointer, then SQLite performs a search for an appropriate
4780 ** temporary file directory.
4782 ** Applications are strongly discouraged from using this global variable.
4783 ** It is required to set a temporary folder on Windows Runtime (WinRT).
4784 ** But for all other platforms, it is highly recommended that applications
4785 ** neither read nor write this variable. This global variable is a relic
4786 ** that exists for backwards compatibility of legacy applications and should
4787 ** be avoided in new projects.
4789 ** It is not safe to read or modify this variable in more than one
4790 ** thread at a time. It is not safe to read or modify this variable
4791 ** if a [database connection] is being used at the same time in a separate
4793 ** It is intended that this variable be set once
4794 ** as part of process initialization and before any SQLite interface
4795 ** routines have been called and that this variable remain unchanged
4798 ** ^The [temp_store_directory pragma] may modify this variable and cause
4799 ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,
4800 ** the [temp_store_directory pragma] always assumes that any string
4801 ** that this variable points to is held in memory obtained from
4802 ** [sqlite3_malloc] and the pragma may attempt to free that memory
4803 ** using [sqlite3_free].
4804 ** Hence, if this variable is modified directly, either it should be
4805 ** made NULL or made to point to memory obtained from [sqlite3_malloc]
4806 ** or else the use of the [temp_store_directory pragma] should be avoided.
4807 ** Except when requested by the [temp_store_directory pragma], SQLite
4808 ** does not free the memory that sqlite3_temp_directory points to. If
4809 ** the application wants that memory to be freed, it must do
4810 ** so itself, taking care to only do so after all [database connection]
4811 ** objects have been destroyed.
4813 ** <b>Note to Windows Runtime users:</b> The temporary directory must be set
4814 ** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various
4815 ** features that require the use of temporary files may fail. Here is an
4816 ** example of how to do this using C++ with the Windows Runtime:
4818 ** <blockquote><pre>
4819 ** LPCWSTR zPath = Windows::Storage::ApplicationData::Current->
4820 ** TemporaryFolder->Path->Data();
4821 ** char zPathBuf[MAX_PATH + 1];
4822 ** memset(zPathBuf, 0, sizeof(zPathBuf));
4823 ** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),
4824 ** NULL, NULL);
4825 ** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);
4826 ** </pre></blockquote>
4828 SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory;
4831 ** CAPI3REF: Name Of The Folder Holding Database Files
4833 ** ^(If this global variable is made to point to a string which is
4834 ** the name of a folder (a.k.a. directory), then all database files
4835 ** specified with a relative pathname and created or accessed by
4836 ** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed
4837 ** to be relative to that directory.)^ ^If this variable is a NULL
4838 ** pointer, then SQLite assumes that all database files specified
4839 ** with a relative pathname are relative to the current directory
4840 ** for the process. Only the windows VFS makes use of this global
4841 ** variable; it is ignored by the unix VFS.
4843 ** Changing the value of this variable while a database connection is
4844 ** open can result in a corrupt database.
4846 ** It is not safe to read or modify this variable in more than one
4847 ** thread at a time. It is not safe to read or modify this variable
4848 ** if a [database connection] is being used at the same time in a separate
4850 ** It is intended that this variable be set once
4851 ** as part of process initialization and before any SQLite interface
4852 ** routines have been called and that this variable remain unchanged
4855 ** ^The [data_store_directory pragma] may modify this variable and cause
4856 ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,
4857 ** the [data_store_directory pragma] always assumes that any string
4858 ** that this variable points to is held in memory obtained from
4859 ** [sqlite3_malloc] and the pragma may attempt to free that memory
4860 ** using [sqlite3_free].
4861 ** Hence, if this variable is modified directly, either it should be
4862 ** made NULL or made to point to memory obtained from [sqlite3_malloc]
4863 ** or else the use of the [data_store_directory pragma] should be avoided.
4865 SQLITE_API SQLITE_EXTERN char *sqlite3_data_directory;
4868 ** CAPI3REF: Test For Auto-Commit Mode
4869 ** KEYWORDS: {autocommit mode}
4871 ** ^The sqlite3_get_autocommit() interface returns non-zero or
4872 ** zero if the given database connection is or is not in autocommit mode,
4873 ** respectively. ^Autocommit mode is on by default.
4874 ** ^Autocommit mode is disabled by a [BEGIN] statement.
4875 ** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
4877 ** If certain kinds of errors occur on a statement within a multi-statement
4878 ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
4879 ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
4880 ** transaction might be rolled back automatically. The only way to
4881 ** find out whether SQLite automatically rolled back the transaction after
4882 ** an error is to use this function.
4884 ** If another thread changes the autocommit status of the database
4885 ** connection while this routine is running, then the return value
4888 SQLITE_API int sqlite3_get_autocommit(sqlite3*);
4891 ** CAPI3REF: Find The Database Handle Of A Prepared Statement
4893 ** ^The sqlite3_db_handle interface returns the [database connection] handle
4894 ** to which a [prepared statement] belongs. ^The [database connection]
4895 ** returned by sqlite3_db_handle is the same [database connection]
4896 ** that was the first argument
4897 ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
4898 ** create the statement in the first place.
4900 SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
4903 ** CAPI3REF: Return The Filename For A Database Connection
4905 ** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename
4906 ** associated with database N of connection D. ^The main database file
4907 ** has the name "main". If there is no attached database N on the database
4908 ** connection D, or if database N is a temporary or in-memory database, then
4909 ** a NULL pointer is returned.
4911 ** ^The filename returned by this function is the output of the
4912 ** xFullPathname method of the [VFS]. ^In other words, the filename
4913 ** will be an absolute pathname, even if the filename used
4914 ** to open the database originally was a URI or relative pathname.
4916 SQLITE_API const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName);
4919 ** CAPI3REF: Determine if a database is read-only
4921 ** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N
4922 ** of connection D is read-only, 0 if it is read/write, or -1 if N is not
4923 ** the name of a database on connection D.
4925 SQLITE_API int sqlite3_db_readonly(sqlite3 *db, const char *zDbName);
4928 ** CAPI3REF: Find the next prepared statement
4930 ** ^This interface returns a pointer to the next [prepared statement] after
4931 ** pStmt associated with the [database connection] pDb. ^If pStmt is NULL
4932 ** then this interface returns a pointer to the first prepared statement
4933 ** associated with the database connection pDb. ^If no prepared statement
4934 ** satisfies the conditions of this routine, it returns NULL.
4936 ** The [database connection] pointer D in a call to
4937 ** [sqlite3_next_stmt(D,S)] must refer to an open database
4938 ** connection and in particular must not be a NULL pointer.
4940 SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
4943 ** CAPI3REF: Commit And Rollback Notification Callbacks
4945 ** ^The sqlite3_commit_hook() interface registers a callback
4946 ** function to be invoked whenever a transaction is [COMMIT | committed].
4947 ** ^Any callback set by a previous call to sqlite3_commit_hook()
4948 ** for the same database connection is overridden.
4949 ** ^The sqlite3_rollback_hook() interface registers a callback
4950 ** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
4951 ** ^Any callback set by a previous call to sqlite3_rollback_hook()
4952 ** for the same database connection is overridden.
4953 ** ^The pArg argument is passed through to the callback.
4954 ** ^If the callback on a commit hook function returns non-zero,
4955 ** then the commit is converted into a rollback.
4957 ** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
4958 ** return the P argument from the previous call of the same function
4959 ** on the same [database connection] D, or NULL for
4960 ** the first call for each function on D.
4962 ** The commit and rollback hook callbacks are not reentrant.
4963 ** The callback implementation must not do anything that will modify
4964 ** the database connection that invoked the callback. Any actions
4965 ** to modify the database connection must be deferred until after the
4966 ** completion of the [sqlite3_step()] call that triggered the commit
4967 ** or rollback hook in the first place.
4968 ** Note that running any other SQL statements, including SELECT statements,
4969 ** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
4970 ** the database connections for the meaning of "modify" in this paragraph.
4972 ** ^Registering a NULL function disables the callback.
4974 ** ^When the commit hook callback routine returns zero, the [COMMIT]
4975 ** operation is allowed to continue normally. ^If the commit hook
4976 ** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
4977 ** ^The rollback hook is invoked on a rollback that results from a commit
4978 ** hook returning non-zero, just as it would be with any other rollback.
4980 ** ^For the purposes of this API, a transaction is said to have been
4981 ** rolled back if an explicit "ROLLBACK" statement is executed, or
4982 ** an error or constraint causes an implicit rollback to occur.
4983 ** ^The rollback callback is not invoked if a transaction is
4984 ** automatically rolled back because the database connection is closed.
4986 ** See also the [sqlite3_update_hook()] interface.
4988 SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
4989 SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
4992 ** CAPI3REF: Data Change Notification Callbacks
4994 ** ^The sqlite3_update_hook() interface registers a callback function
4995 ** with the [database connection] identified by the first argument
4996 ** to be invoked whenever a row is updated, inserted or deleted in
4998 ** ^Any callback set by a previous call to this function
4999 ** for the same database connection is overridden.
5001 ** ^The second argument is a pointer to the function to invoke when a
5002 ** row is updated, inserted or deleted in a rowid table.
5003 ** ^The first argument to the callback is a copy of the third argument
5004 ** to sqlite3_update_hook().
5005 ** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
5006 ** or [SQLITE_UPDATE], depending on the operation that caused the callback
5008 ** ^The third and fourth arguments to the callback contain pointers to the
5009 ** database and table name containing the affected row.
5010 ** ^The final callback parameter is the [rowid] of the row.
5011 ** ^In the case of an update, this is the [rowid] after the update takes place.
5013 ** ^(The update hook is not invoked when internal system tables are
5014 ** modified (i.e. sqlite_master and sqlite_sequence).)^
5015 ** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified.
5017 ** ^In the current implementation, the update hook
5018 ** is not invoked when duplication rows are deleted because of an
5019 ** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook
5020 ** invoked when rows are deleted using the [truncate optimization].
5021 ** The exceptions defined in this paragraph might change in a future
5022 ** release of SQLite.
5024 ** The update hook implementation must not do anything that will modify
5025 ** the database connection that invoked the update hook. Any actions
5026 ** to modify the database connection must be deferred until after the
5027 ** completion of the [sqlite3_step()] call that triggered the update hook.
5028 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
5029 ** database connections for the meaning of "modify" in this paragraph.
5031 ** ^The sqlite3_update_hook(D,C,P) function
5032 ** returns the P argument from the previous call
5033 ** on the same [database connection] D, or NULL for
5034 ** the first call on D.
5036 ** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()]
5039 SQLITE_API void *sqlite3_update_hook(
5041 void(*)(void *,int ,char const *,char const *,sqlite3_int64),
5046 ** CAPI3REF: Enable Or Disable Shared Pager Cache
5048 ** ^(This routine enables or disables the sharing of the database cache
5049 ** and schema data structures between [database connection | connections]
5050 ** to the same database. Sharing is enabled if the argument is true
5051 ** and disabled if the argument is false.)^
5053 ** ^Cache sharing is enabled and disabled for an entire process.
5054 ** This is a change as of SQLite version 3.5.0. In prior versions of SQLite,
5055 ** sharing was enabled or disabled for each thread separately.
5057 ** ^(The cache sharing mode set by this interface effects all subsequent
5058 ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
5059 ** Existing database connections continue use the sharing mode
5060 ** that was in effect at the time they were opened.)^
5062 ** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
5063 ** successfully. An [error code] is returned otherwise.)^
5065 ** ^Shared cache is disabled by default. But this might change in
5066 ** future releases of SQLite. Applications that care about shared
5067 ** cache setting should set it explicitly.
5069 ** This interface is threadsafe on processors where writing a
5070 ** 32-bit integer is atomic.
5072 ** See Also: [SQLite Shared-Cache Mode]
5074 SQLITE_API int sqlite3_enable_shared_cache(int);
5077 ** CAPI3REF: Attempt To Free Heap Memory
5079 ** ^The sqlite3_release_memory() interface attempts to free N bytes
5080 ** of heap memory by deallocating non-essential memory allocations
5081 ** held by the database library. Memory used to cache database
5082 ** pages to improve performance is an example of non-essential memory.
5083 ** ^sqlite3_release_memory() returns the number of bytes actually freed,
5084 ** which might be more or less than the amount requested.
5085 ** ^The sqlite3_release_memory() routine is a no-op returning zero
5086 ** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
5088 ** See also: [sqlite3_db_release_memory()]
5090 SQLITE_API int sqlite3_release_memory(int);
5093 ** CAPI3REF: Free Memory Used By A Database Connection
5095 ** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap
5096 ** memory as possible from database connection D. Unlike the
5097 ** [sqlite3_release_memory()] interface, this interface is in effect even
5098 ** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
5101 ** See also: [sqlite3_release_memory()]
5103 SQLITE_API int sqlite3_db_release_memory(sqlite3*);
5106 ** CAPI3REF: Impose A Limit On Heap Size
5108 ** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
5109 ** soft limit on the amount of heap memory that may be allocated by SQLite.
5110 ** ^SQLite strives to keep heap memory utilization below the soft heap
5111 ** limit by reducing the number of pages held in the page cache
5112 ** as heap memory usages approaches the limit.
5113 ** ^The soft heap limit is "soft" because even though SQLite strives to stay
5114 ** below the limit, it will exceed the limit rather than generate
5115 ** an [SQLITE_NOMEM] error. In other words, the soft heap limit
5116 ** is advisory only.
5118 ** ^The return value from sqlite3_soft_heap_limit64() is the size of
5119 ** the soft heap limit prior to the call, or negative in the case of an
5120 ** error. ^If the argument N is negative
5121 ** then no change is made to the soft heap limit. Hence, the current
5122 ** size of the soft heap limit can be determined by invoking
5123 ** sqlite3_soft_heap_limit64() with a negative argument.
5125 ** ^If the argument N is zero then the soft heap limit is disabled.
5127 ** ^(The soft heap limit is not enforced in the current implementation
5128 ** if one or more of following conditions are true:
5131 ** <li> The soft heap limit is set to zero.
5132 ** <li> Memory accounting is disabled using a combination of the
5133 ** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
5134 ** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
5135 ** <li> An alternative page cache implementation is specified using
5136 ** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
5137 ** <li> The page cache allocates from its own memory pool supplied
5138 ** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
5142 ** Beginning with SQLite version 3.7.3, the soft heap limit is enforced
5143 ** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT]
5144 ** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT],
5145 ** the soft heap limit is enforced on every memory allocation. Without
5146 ** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced
5147 ** when memory is allocated by the page cache. Testing suggests that because
5148 ** the page cache is the predominate memory user in SQLite, most
5149 ** applications will achieve adequate soft heap limit enforcement without
5150 ** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT].
5152 ** The circumstances under which SQLite will enforce the soft heap limit may
5153 ** changes in future releases of SQLite.
5155 SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);
5158 ** CAPI3REF: Deprecated Soft Heap Limit Interface
5161 ** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
5162 ** interface. This routine is provided for historical compatibility
5163 ** only. All new applications should use the
5164 ** [sqlite3_soft_heap_limit64()] interface rather than this one.
5166 SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N);
5170 ** CAPI3REF: Extract Metadata About A Column Of A Table
5172 ** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns
5173 ** information about column C of table T in database D
5174 ** on [database connection] X.)^ ^The sqlite3_table_column_metadata()
5175 ** interface returns SQLITE_OK and fills in the non-NULL pointers in
5176 ** the final five arguments with appropriate values if the specified
5177 ** column exists. ^The sqlite3_table_column_metadata() interface returns
5178 ** SQLITE_ERROR and if the specified column does not exist.
5179 ** ^If the column-name parameter to sqlite3_table_column_metadata() is a
5180 ** NULL pointer, then this routine simply checks for the existance of the
5181 ** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it
5184 ** ^The column is identified by the second, third and fourth parameters to
5185 ** this function. ^(The second parameter is either the name of the database
5186 ** (i.e. "main", "temp", or an attached database) containing the specified
5187 ** table or NULL.)^ ^If it is NULL, then all attached databases are searched
5188 ** for the table using the same algorithm used by the database engine to
5189 ** resolve unqualified table references.
5191 ** ^The third and fourth parameters to this function are the table and column
5192 ** name of the desired column, respectively.
5194 ** ^Metadata is returned by writing to the memory locations passed as the 5th
5195 ** and subsequent parameters to this function. ^Any of these arguments may be
5196 ** NULL, in which case the corresponding element of metadata is omitted.
5199 ** <table border="1">
5200 ** <tr><th> Parameter <th> Output<br>Type <th> Description
5202 ** <tr><td> 5th <td> const char* <td> Data type
5203 ** <tr><td> 6th <td> const char* <td> Name of default collation sequence
5204 ** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint
5205 ** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY
5206 ** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT]
5210 ** ^The memory pointed to by the character pointers returned for the
5211 ** declaration type and collation sequence is valid until the next
5212 ** call to any SQLite API function.
5214 ** ^If the specified table is actually a view, an [error code] is returned.
5216 ** ^If the specified column is "rowid", "oid" or "_rowid_" and the table
5217 ** is not a [WITHOUT ROWID] table and an
5218 ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
5219 ** parameters are set for the explicitly declared column. ^(If there is no
5220 ** [INTEGER PRIMARY KEY] column, then the outputs
5221 ** for the [rowid] are set as follows:
5224 ** data type: "INTEGER"
5225 ** collation sequence: "BINARY"
5228 ** auto increment: 0
5231 ** ^This function causes all database schemas to be read from disk and
5232 ** parsed, if that has not already been done, and returns an error if
5233 ** any errors are encountered while loading the schema.
5235 SQLITE_API int sqlite3_table_column_metadata(
5236 sqlite3 *db, /* Connection handle */
5237 const char *zDbName, /* Database name or NULL */
5238 const char *zTableName, /* Table name */
5239 const char *zColumnName, /* Column name */
5240 char const **pzDataType, /* OUTPUT: Declared data type */
5241 char const **pzCollSeq, /* OUTPUT: Collation sequence name */
5242 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */
5243 int *pPrimaryKey, /* OUTPUT: True if column part of PK */
5244 int *pAutoinc /* OUTPUT: True if column is auto-increment */
5248 ** CAPI3REF: Load An Extension
5250 ** ^This interface loads an SQLite extension library from the named file.
5252 ** ^The sqlite3_load_extension() interface attempts to load an
5253 ** [SQLite extension] library contained in the file zFile. If
5254 ** the file cannot be loaded directly, attempts are made to load
5255 ** with various operating-system specific extensions added.
5256 ** So for example, if "samplelib" cannot be loaded, then names like
5257 ** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might
5260 ** ^The entry point is zProc.
5261 ** ^(zProc may be 0, in which case SQLite will try to come up with an
5262 ** entry point name on its own. It first tries "sqlite3_extension_init".
5263 ** If that does not work, it constructs a name "sqlite3_X_init" where the
5264 ** X is consists of the lower-case equivalent of all ASCII alphabetic
5265 ** characters in the filename from the last "/" to the first following
5266 ** "." and omitting any initial "lib".)^
5267 ** ^The sqlite3_load_extension() interface returns
5268 ** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
5269 ** ^If an error occurs and pzErrMsg is not 0, then the
5270 ** [sqlite3_load_extension()] interface shall attempt to
5271 ** fill *pzErrMsg with error message text stored in memory
5272 ** obtained from [sqlite3_malloc()]. The calling function
5273 ** should free this memory by calling [sqlite3_free()].
5275 ** ^Extension loading must be enabled using
5276 ** [sqlite3_enable_load_extension()] prior to calling this API,
5277 ** otherwise an error will be returned.
5279 ** See also the [load_extension() SQL function].
5281 SQLITE_API int sqlite3_load_extension(
5282 sqlite3 *db, /* Load the extension into this database connection */
5283 const char *zFile, /* Name of the shared library containing extension */
5284 const char *zProc, /* Entry point. Derived from zFile if 0 */
5285 char **pzErrMsg /* Put error message here if not 0 */
5289 ** CAPI3REF: Enable Or Disable Extension Loading
5291 ** ^So as not to open security holes in older applications that are
5292 ** unprepared to deal with [extension loading], and as a means of disabling
5293 ** [extension loading] while evaluating user-entered SQL, the following API
5294 ** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
5296 ** ^Extension loading is off by default.
5297 ** ^Call the sqlite3_enable_load_extension() routine with onoff==1
5298 ** to turn extension loading on and call it with onoff==0 to turn
5299 ** it back off again.
5301 SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
5304 ** CAPI3REF: Automatically Load Statically Linked Extensions
5306 ** ^This interface causes the xEntryPoint() function to be invoked for
5307 ** each new [database connection] that is created. The idea here is that
5308 ** xEntryPoint() is the entry point for a statically linked [SQLite extension]
5309 ** that is to be automatically loaded into all new database connections.
5311 ** ^(Even though the function prototype shows that xEntryPoint() takes
5312 ** no arguments and returns void, SQLite invokes xEntryPoint() with three
5313 ** arguments and expects and integer result as if the signature of the
5314 ** entry point where as follows:
5316 ** <blockquote><pre>
5317 ** int xEntryPoint(
5318 ** sqlite3 *db,
5319 ** const char **pzErrMsg,
5320 ** const struct sqlite3_api_routines *pThunk
5322 ** </pre></blockquote>)^
5324 ** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
5325 ** point to an appropriate error message (obtained from [sqlite3_mprintf()])
5326 ** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg
5327 ** is NULL before calling the xEntryPoint(). ^SQLite will invoke
5328 ** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any
5329 ** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
5330 ** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
5332 ** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
5333 ** on the list of automatic extensions is a harmless no-op. ^No entry point
5334 ** will be called more than once for each database connection that is opened.
5336 ** See also: [sqlite3_reset_auto_extension()]
5337 ** and [sqlite3_cancel_auto_extension()]
5339 SQLITE_API int sqlite3_auto_extension(void (*xEntryPoint)(void));
5342 ** CAPI3REF: Cancel Automatic Extension Loading
5344 ** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the
5345 ** initialization routine X that was registered using a prior call to
5346 ** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)]
5347 ** routine returns 1 if initialization routine X was successfully
5348 ** unregistered and it returns 0 if X was not on the list of initialization
5351 SQLITE_API int sqlite3_cancel_auto_extension(void (*xEntryPoint)(void));
5354 ** CAPI3REF: Reset Automatic Extension Loading
5356 ** ^This interface disables all automatic extensions previously
5357 ** registered using [sqlite3_auto_extension()].
5359 SQLITE_API void sqlite3_reset_auto_extension(void);
5362 ** The interface to the virtual-table mechanism is currently considered
5363 ** to be experimental. The interface might change in incompatible ways.
5364 ** If this is a problem for you, do not use the interface at this time.
5366 ** When the virtual-table mechanism stabilizes, we will declare the
5367 ** interface fixed, support it indefinitely, and remove this comment.
5371 ** Structures used by the virtual table interface
5373 typedef struct sqlite3_vtab sqlite3_vtab;
5374 typedef struct sqlite3_index_info sqlite3_index_info;
5375 typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
5376 typedef struct sqlite3_module sqlite3_module;
5379 ** CAPI3REF: Virtual Table Object
5380 ** KEYWORDS: sqlite3_module {virtual table module}
5382 ** This structure, sometimes called a "virtual table module",
5383 ** defines the implementation of a [virtual tables].
5384 ** This structure consists mostly of methods for the module.
5386 ** ^A virtual table module is created by filling in a persistent
5387 ** instance of this structure and passing a pointer to that instance
5388 ** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
5389 ** ^The registration remains valid until it is replaced by a different
5390 ** module or until the [database connection] closes. The content
5391 ** of this structure must not change while it is registered with
5392 ** any database connection.
5394 struct sqlite3_module {
5396 int (*xCreate)(sqlite3*, void *pAux,
5397 int argc, const char *const*argv,
5398 sqlite3_vtab **ppVTab, char**);
5399 int (*xConnect)(sqlite3*, void *pAux,
5400 int argc, const char *const*argv,
5401 sqlite3_vtab **ppVTab, char**);
5402 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
5403 int (*xDisconnect)(sqlite3_vtab *pVTab);
5404 int (*xDestroy)(sqlite3_vtab *pVTab);
5405 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
5406 int (*xClose)(sqlite3_vtab_cursor*);
5407 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
5408 int argc, sqlite3_value **argv);
5409 int (*xNext)(sqlite3_vtab_cursor*);
5410 int (*xEof)(sqlite3_vtab_cursor*);
5411 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
5412 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
5413 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
5414 int (*xBegin)(sqlite3_vtab *pVTab);
5415 int (*xSync)(sqlite3_vtab *pVTab);
5416 int (*xCommit)(sqlite3_vtab *pVTab);
5417 int (*xRollback)(sqlite3_vtab *pVTab);
5418 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
5419 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
5421 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
5422 /* The methods above are in version 1 of the sqlite_module object. Those
5423 ** below are for version 2 and greater. */
5424 int (*xSavepoint)(sqlite3_vtab *pVTab, int);
5425 int (*xRelease)(sqlite3_vtab *pVTab, int);
5426 int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
5430 ** CAPI3REF: Virtual Table Indexing Information
5431 ** KEYWORDS: sqlite3_index_info
5433 ** The sqlite3_index_info structure and its substructures is used as part
5434 ** of the [virtual table] interface to
5435 ** pass information into and receive the reply from the [xBestIndex]
5436 ** method of a [virtual table module]. The fields under **Inputs** are the
5437 ** inputs to xBestIndex and are read-only. xBestIndex inserts its
5438 ** results into the **Outputs** fields.
5440 ** ^(The aConstraint[] array records WHERE clause constraints of the form:
5442 ** <blockquote>column OP expr</blockquote>
5444 ** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is
5445 ** stored in aConstraint[].op using one of the
5446 ** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
5447 ** ^(The index of the column is stored in
5448 ** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the
5449 ** expr on the right-hand side can be evaluated (and thus the constraint
5450 ** is usable) and false if it cannot.)^
5452 ** ^The optimizer automatically inverts terms of the form "expr OP column"
5453 ** and makes other simplifications to the WHERE clause in an attempt to
5454 ** get as many WHERE clause terms into the form shown above as possible.
5455 ** ^The aConstraint[] array only reports WHERE clause terms that are
5456 ** relevant to the particular virtual table being queried.
5458 ** ^Information about the ORDER BY clause is stored in aOrderBy[].
5459 ** ^Each term of aOrderBy records a column of the ORDER BY clause.
5461 ** The [xBestIndex] method must fill aConstraintUsage[] with information
5462 ** about what parameters to pass to xFilter. ^If argvIndex>0 then
5463 ** the right-hand side of the corresponding aConstraint[] is evaluated
5464 ** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit
5465 ** is true, then the constraint is assumed to be fully handled by the
5466 ** virtual table and is not checked again by SQLite.)^
5468 ** ^The idxNum and idxPtr values are recorded and passed into the
5469 ** [xFilter] method.
5470 ** ^[sqlite3_free()] is used to free idxPtr if and only if
5471 ** needToFreeIdxPtr is true.
5473 ** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
5474 ** the correct order to satisfy the ORDER BY clause so that no separate
5475 ** sorting step is required.
5477 ** ^The estimatedCost value is an estimate of the cost of a particular
5478 ** strategy. A cost of N indicates that the cost of the strategy is similar
5479 ** to a linear scan of an SQLite table with N rows. A cost of log(N)
5480 ** indicates that the expense of the operation is similar to that of a
5481 ** binary search on a unique indexed field of an SQLite table with N rows.
5483 ** ^The estimatedRows value is an estimate of the number of rows that
5484 ** will be returned by the strategy.
5486 ** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info
5487 ** structure for SQLite version 3.8.2. If a virtual table extension is
5488 ** used with an SQLite version earlier than 3.8.2, the results of attempting
5489 ** to read or write the estimatedRows field are undefined (but are likely
5490 ** to included crashing the application). The estimatedRows field should
5491 ** therefore only be used if [sqlite3_libversion_number()] returns a
5492 ** value greater than or equal to 3008002.
5494 struct sqlite3_index_info {
5496 int nConstraint; /* Number of entries in aConstraint */
5497 struct sqlite3_index_constraint {
5498 int iColumn; /* Column on left-hand side of constraint */
5499 unsigned char op; /* Constraint operator */
5500 unsigned char usable; /* True if this constraint is usable */
5501 int iTermOffset; /* Used internally - xBestIndex should ignore */
5502 } *aConstraint; /* Table of WHERE clause constraints */
5503 int nOrderBy; /* Number of terms in the ORDER BY clause */
5504 struct sqlite3_index_orderby {
5505 int iColumn; /* Column number */
5506 unsigned char desc; /* True for DESC. False for ASC. */
5507 } *aOrderBy; /* The ORDER BY clause */
5509 struct sqlite3_index_constraint_usage {
5510 int argvIndex; /* if >0, constraint is part of argv to xFilter */
5511 unsigned char omit; /* Do not code a test for this constraint */
5512 } *aConstraintUsage;
5513 int idxNum; /* Number used to identify the index */
5514 char *idxStr; /* String, possibly obtained from sqlite3_malloc */
5515 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */
5516 int orderByConsumed; /* True if output is already ordered */
5517 double estimatedCost; /* Estimated cost of using this index */
5518 /* Fields below are only available in SQLite 3.8.2 and later */
5519 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */
5523 ** CAPI3REF: Virtual Table Constraint Operator Codes
5525 ** These macros defined the allowed values for the
5526 ** [sqlite3_index_info].aConstraint[].op field. Each value represents
5527 ** an operator that is part of a constraint term in the wHERE clause of
5528 ** a query that uses a [virtual table].
5530 #define SQLITE_INDEX_CONSTRAINT_EQ 2
5531 #define SQLITE_INDEX_CONSTRAINT_GT 4
5532 #define SQLITE_INDEX_CONSTRAINT_LE 8
5533 #define SQLITE_INDEX_CONSTRAINT_LT 16
5534 #define SQLITE_INDEX_CONSTRAINT_GE 32
5535 #define SQLITE_INDEX_CONSTRAINT_MATCH 64
5538 ** CAPI3REF: Register A Virtual Table Implementation
5540 ** ^These routines are used to register a new [virtual table module] name.
5541 ** ^Module names must be registered before
5542 ** creating a new [virtual table] using the module and before using a
5543 ** preexisting [virtual table] for the module.
5545 ** ^The module name is registered on the [database connection] specified
5546 ** by the first parameter. ^The name of the module is given by the
5547 ** second parameter. ^The third parameter is a pointer to
5548 ** the implementation of the [virtual table module]. ^The fourth
5549 ** parameter is an arbitrary client data pointer that is passed through
5550 ** into the [xCreate] and [xConnect] methods of the virtual table module
5551 ** when a new virtual table is be being created or reinitialized.
5553 ** ^The sqlite3_create_module_v2() interface has a fifth parameter which
5554 ** is a pointer to a destructor for the pClientData. ^SQLite will
5555 ** invoke the destructor function (if it is not NULL) when SQLite
5556 ** no longer needs the pClientData pointer. ^The destructor will also
5557 ** be invoked if the call to sqlite3_create_module_v2() fails.
5558 ** ^The sqlite3_create_module()
5559 ** interface is equivalent to sqlite3_create_module_v2() with a NULL
5562 SQLITE_API int sqlite3_create_module(
5563 sqlite3 *db, /* SQLite connection to register module with */
5564 const char *zName, /* Name of the module */
5565 const sqlite3_module *p, /* Methods for the module */
5566 void *pClientData /* Client data for xCreate/xConnect */
5568 SQLITE_API int sqlite3_create_module_v2(
5569 sqlite3 *db, /* SQLite connection to register module with */
5570 const char *zName, /* Name of the module */
5571 const sqlite3_module *p, /* Methods for the module */
5572 void *pClientData, /* Client data for xCreate/xConnect */
5573 void(*xDestroy)(void*) /* Module destructor function */
5577 ** CAPI3REF: Virtual Table Instance Object
5578 ** KEYWORDS: sqlite3_vtab
5580 ** Every [virtual table module] implementation uses a subclass
5581 ** of this object to describe a particular instance
5582 ** of the [virtual table]. Each subclass will
5583 ** be tailored to the specific needs of the module implementation.
5584 ** The purpose of this superclass is to define certain fields that are
5585 ** common to all module implementations.
5587 ** ^Virtual tables methods can set an error message by assigning a
5588 ** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should
5589 ** take care that any prior string is freed by a call to [sqlite3_free()]
5590 ** prior to assigning a new string to zErrMsg. ^After the error message
5591 ** is delivered up to the client application, the string will be automatically
5592 ** freed by sqlite3_free() and the zErrMsg field will be zeroed.
5594 struct sqlite3_vtab {
5595 const sqlite3_module *pModule; /* The module for this virtual table */
5596 int nRef; /* NO LONGER USED */
5597 char *zErrMsg; /* Error message from sqlite3_mprintf() */
5598 /* Virtual table implementations will typically add additional fields */
5602 ** CAPI3REF: Virtual Table Cursor Object
5603 ** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
5605 ** Every [virtual table module] implementation uses a subclass of the
5606 ** following structure to describe cursors that point into the
5607 ** [virtual table] and are used
5608 ** to loop through the virtual table. Cursors are created using the
5609 ** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
5610 ** by the [sqlite3_module.xClose | xClose] method. Cursors are used
5611 ** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
5612 ** of the module. Each module implementation will define
5613 ** the content of a cursor structure to suit its own needs.
5615 ** This superclass exists in order to define fields of the cursor that
5616 ** are common to all implementations.
5618 struct sqlite3_vtab_cursor {
5619 sqlite3_vtab *pVtab; /* Virtual table of this cursor */
5620 /* Virtual table implementations will typically add additional fields */
5624 ** CAPI3REF: Declare The Schema Of A Virtual Table
5626 ** ^The [xCreate] and [xConnect] methods of a
5627 ** [virtual table module] call this interface
5628 ** to declare the format (the names and datatypes of the columns) of
5629 ** the virtual tables they implement.
5631 SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
5634 ** CAPI3REF: Overload A Function For A Virtual Table
5636 ** ^(Virtual tables can provide alternative implementations of functions
5637 ** using the [xFindFunction] method of the [virtual table module].
5638 ** But global versions of those functions
5639 ** must exist in order to be overloaded.)^
5641 ** ^(This API makes sure a global version of a function with a particular
5642 ** name and number of parameters exists. If no such function exists
5643 ** before this API is called, a new function is created.)^ ^The implementation
5644 ** of the new function always causes an exception to be thrown. So
5645 ** the new function is not good for anything by itself. Its only
5646 ** purpose is to be a placeholder function that can be overloaded
5647 ** by a [virtual table].
5649 SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
5652 ** The interface to the virtual-table mechanism defined above (back up
5653 ** to a comment remarkably similar to this one) is currently considered
5654 ** to be experimental. The interface might change in incompatible ways.
5655 ** If this is a problem for you, do not use the interface at this time.
5657 ** When the virtual-table mechanism stabilizes, we will declare the
5658 ** interface fixed, support it indefinitely, and remove this comment.
5662 ** CAPI3REF: A Handle To An Open BLOB
5663 ** KEYWORDS: {BLOB handle} {BLOB handles}
5665 ** An instance of this object represents an open BLOB on which
5666 ** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
5667 ** ^Objects of this type are created by [sqlite3_blob_open()]
5668 ** and destroyed by [sqlite3_blob_close()].
5669 ** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
5670 ** can be used to read or write small subsections of the BLOB.
5671 ** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
5673 typedef struct sqlite3_blob sqlite3_blob;
5676 ** CAPI3REF: Open A BLOB For Incremental I/O
5678 ** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
5679 ** in row iRow, column zColumn, table zTable in database zDb;
5680 ** in other words, the same BLOB that would be selected by:
5683 ** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
5686 ** ^(Parameter zDb is not the filename that contains the database, but
5687 ** rather the symbolic name of the database. For attached databases, this is
5688 ** the name that appears after the AS keyword in the [ATTACH] statement.
5689 ** For the main database file, the database name is "main". For TEMP
5690 ** tables, the database name is "temp".)^
5692 ** ^If the flags parameter is non-zero, then the BLOB is opened for read
5693 ** and write access. ^If the flags parameter is zero, the BLOB is opened for
5694 ** read-only access.
5696 ** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored
5697 ** in *ppBlob. Otherwise an [error code] is returned and, unless the error
5698 ** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided
5699 ** the API is not misused, it is always safe to call [sqlite3_blob_close()]
5700 ** on *ppBlob after this function it returns.
5702 ** This function fails with SQLITE_ERROR if any of the following are true:
5704 ** <li> ^(Database zDb does not exist)^,
5705 ** <li> ^(Table zTable does not exist within database zDb)^,
5706 ** <li> ^(Table zTable is a WITHOUT ROWID table)^,
5707 ** <li> ^(Column zColumn does not exist)^,
5708 ** <li> ^(Row iRow is not present in the table)^,
5709 ** <li> ^(The specified column of row iRow contains a value that is not
5710 ** a TEXT or BLOB value)^,
5711 ** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE
5712 ** constraint and the blob is being opened for read/write access)^,
5713 ** <li> ^([foreign key constraints | Foreign key constraints] are enabled,
5714 ** column zColumn is part of a [child key] definition and the blob is
5715 ** being opened for read/write access)^.
5718 ** ^Unless it returns SQLITE_MISUSE, this function sets the
5719 ** [database connection] error code and message accessible via
5720 ** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
5723 ** ^(If the row that a BLOB handle points to is modified by an
5724 ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
5725 ** then the BLOB handle is marked as "expired".
5726 ** This is true if any column of the row is changed, even a column
5727 ** other than the one the BLOB handle is open on.)^
5728 ** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
5729 ** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
5730 ** ^(Changes written into a BLOB prior to the BLOB expiring are not
5731 ** rolled back by the expiration of the BLOB. Such changes will eventually
5732 ** commit if the transaction continues to completion.)^
5734 ** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
5735 ** the opened blob. ^The size of a blob may not be changed by this
5736 ** interface. Use the [UPDATE] SQL command to change the size of a
5739 ** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
5740 ** and the built-in [zeroblob] SQL function may be used to create a
5741 ** zero-filled blob to read or write using the incremental-blob interface.
5743 ** To avoid a resource leak, every open [BLOB handle] should eventually
5744 ** be released by a call to [sqlite3_blob_close()].
5746 SQLITE_API int sqlite3_blob_open(
5750 const char *zColumn,
5753 sqlite3_blob **ppBlob
5757 ** CAPI3REF: Move a BLOB Handle to a New Row
5759 ** ^This function is used to move an existing blob handle so that it points
5760 ** to a different row of the same database table. ^The new row is identified
5761 ** by the rowid value passed as the second argument. Only the row can be
5762 ** changed. ^The database, table and column on which the blob handle is open
5763 ** remain the same. Moving an existing blob handle to a new row can be
5764 ** faster than closing the existing handle and opening a new one.
5766 ** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
5767 ** it must exist and there must be either a blob or text value stored in
5768 ** the nominated column.)^ ^If the new row is not present in the table, or if
5769 ** it does not contain a blob or text value, or if another error occurs, an
5770 ** SQLite error code is returned and the blob handle is considered aborted.
5771 ** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
5772 ** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
5773 ** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
5774 ** always returns zero.
5776 ** ^This function sets the database handle error code and message.
5778 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
5781 ** CAPI3REF: Close A BLOB Handle
5783 ** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed
5784 ** unconditionally. Even if this routine returns an error code, the
5785 ** handle is still closed.)^
5787 ** ^If the blob handle being closed was opened for read-write access, and if
5788 ** the database is in auto-commit mode and there are no other open read-write
5789 ** blob handles or active write statements, the current transaction is
5790 ** committed. ^If an error occurs while committing the transaction, an error
5791 ** code is returned and the transaction rolled back.
5793 ** Calling this function with an argument that is not a NULL pointer or an
5794 ** open blob handle results in undefined behaviour. ^Calling this routine
5795 ** with a null pointer (such as would be returned by a failed call to
5796 ** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function
5797 ** is passed a valid open blob handle, the values returned by the
5798 ** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning.
5800 SQLITE_API int sqlite3_blob_close(sqlite3_blob *);
5803 ** CAPI3REF: Return The Size Of An Open BLOB
5805 ** ^Returns the size in bytes of the BLOB accessible via the
5806 ** successfully opened [BLOB handle] in its only argument. ^The
5807 ** incremental blob I/O routines can only read or overwriting existing
5808 ** blob content; they cannot change the size of a blob.
5810 ** This routine only works on a [BLOB handle] which has been created
5811 ** by a prior successful call to [sqlite3_blob_open()] and which has not
5812 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
5813 ** to this routine results in undefined and probably undesirable behavior.
5815 SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *);
5818 ** CAPI3REF: Read Data From A BLOB Incrementally
5820 ** ^(This function is used to read data from an open [BLOB handle] into a
5821 ** caller-supplied buffer. N bytes of data are copied into buffer Z
5822 ** from the open BLOB, starting at offset iOffset.)^
5824 ** ^If offset iOffset is less than N bytes from the end of the BLOB,
5825 ** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is
5826 ** less than zero, [SQLITE_ERROR] is returned and no data is read.
5827 ** ^The size of the blob (and hence the maximum value of N+iOffset)
5828 ** can be determined using the [sqlite3_blob_bytes()] interface.
5830 ** ^An attempt to read from an expired [BLOB handle] fails with an
5831 ** error code of [SQLITE_ABORT].
5833 ** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
5834 ** Otherwise, an [error code] or an [extended error code] is returned.)^
5836 ** This routine only works on a [BLOB handle] which has been created
5837 ** by a prior successful call to [sqlite3_blob_open()] and which has not
5838 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
5839 ** to this routine results in undefined and probably undesirable behavior.
5841 ** See also: [sqlite3_blob_write()].
5843 SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
5846 ** CAPI3REF: Write Data Into A BLOB Incrementally
5848 ** ^(This function is used to write data into an open [BLOB handle] from a
5849 ** caller-supplied buffer. N bytes of data are copied from the buffer Z
5850 ** into the open BLOB, starting at offset iOffset.)^
5852 ** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
5853 ** Otherwise, an [error code] or an [extended error code] is returned.)^
5854 ** ^Unless SQLITE_MISUSE is returned, this function sets the
5855 ** [database connection] error code and message accessible via
5856 ** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
5858 ** ^If the [BLOB handle] passed as the first argument was not opened for
5859 ** writing (the flags parameter to [sqlite3_blob_open()] was zero),
5860 ** this function returns [SQLITE_READONLY].
5862 ** This function may only modify the contents of the BLOB; it is
5863 ** not possible to increase the size of a BLOB using this API.
5864 ** ^If offset iOffset is less than N bytes from the end of the BLOB,
5865 ** [SQLITE_ERROR] is returned and no data is written. The size of the
5866 ** BLOB (and hence the maximum value of N+iOffset) can be determined
5867 ** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less
5868 ** than zero [SQLITE_ERROR] is returned and no data is written.
5870 ** ^An attempt to write to an expired [BLOB handle] fails with an
5871 ** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred
5872 ** before the [BLOB handle] expired are not rolled back by the
5873 ** expiration of the handle, though of course those changes might
5874 ** have been overwritten by the statement that expired the BLOB handle
5875 ** or by other independent statements.
5877 ** This routine only works on a [BLOB handle] which has been created
5878 ** by a prior successful call to [sqlite3_blob_open()] and which has not
5879 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
5880 ** to this routine results in undefined and probably undesirable behavior.
5882 ** See also: [sqlite3_blob_read()].
5884 SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
5887 ** CAPI3REF: Virtual File System Objects
5889 ** A virtual filesystem (VFS) is an [sqlite3_vfs] object
5890 ** that SQLite uses to interact
5891 ** with the underlying operating system. Most SQLite builds come with a
5892 ** single default VFS that is appropriate for the host computer.
5893 ** New VFSes can be registered and existing VFSes can be unregistered.
5894 ** The following interfaces are provided.
5896 ** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
5897 ** ^Names are case sensitive.
5898 ** ^Names are zero-terminated UTF-8 strings.
5899 ** ^If there is no match, a NULL pointer is returned.
5900 ** ^If zVfsName is NULL then the default VFS is returned.
5902 ** ^New VFSes are registered with sqlite3_vfs_register().
5903 ** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
5904 ** ^The same VFS can be registered multiple times without injury.
5905 ** ^To make an existing VFS into the default VFS, register it again
5906 ** with the makeDflt flag set. If two different VFSes with the
5907 ** same name are registered, the behavior is undefined. If a
5908 ** VFS is registered with a name that is NULL or an empty string,
5909 ** then the behavior is undefined.
5911 ** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
5912 ** ^(If the default VFS is unregistered, another VFS is chosen as
5913 ** the default. The choice for the new VFS is arbitrary.)^
5915 SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
5916 SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
5917 SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*);
5920 ** CAPI3REF: Mutexes
5922 ** The SQLite core uses these routines for thread
5923 ** synchronization. Though they are intended for internal
5924 ** use by SQLite, code that links against SQLite is
5925 ** permitted to use any of these routines.
5927 ** The SQLite source code contains multiple implementations
5928 ** of these mutex routines. An appropriate implementation
5929 ** is selected automatically at compile-time. The following
5930 ** implementations are available in the SQLite core:
5933 ** <li> SQLITE_MUTEX_PTHREADS
5934 ** <li> SQLITE_MUTEX_W32
5935 ** <li> SQLITE_MUTEX_NOOP
5938 ** The SQLITE_MUTEX_NOOP implementation is a set of routines
5939 ** that does no real locking and is appropriate for use in
5940 ** a single-threaded application. The SQLITE_MUTEX_PTHREADS and
5941 ** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
5944 ** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
5945 ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
5946 ** implementation is included with the library. In this case the
5947 ** application must supply a custom mutex implementation using the
5948 ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
5949 ** before calling sqlite3_initialize() or any other public sqlite3_
5950 ** function that calls sqlite3_initialize().
5952 ** ^The sqlite3_mutex_alloc() routine allocates a new
5953 ** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc()
5954 ** routine returns NULL if it is unable to allocate the requested
5955 ** mutex. The argument to sqlite3_mutex_alloc() must one of these
5956 ** integer constants:
5959 ** <li> SQLITE_MUTEX_FAST
5960 ** <li> SQLITE_MUTEX_RECURSIVE
5961 ** <li> SQLITE_MUTEX_STATIC_MASTER
5962 ** <li> SQLITE_MUTEX_STATIC_MEM
5963 ** <li> SQLITE_MUTEX_STATIC_OPEN
5964 ** <li> SQLITE_MUTEX_STATIC_PRNG
5965 ** <li> SQLITE_MUTEX_STATIC_LRU
5966 ** <li> SQLITE_MUTEX_STATIC_PMEM
5967 ** <li> SQLITE_MUTEX_STATIC_APP1
5968 ** <li> SQLITE_MUTEX_STATIC_APP2
5969 ** <li> SQLITE_MUTEX_STATIC_APP3
5972 ** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
5973 ** cause sqlite3_mutex_alloc() to create
5974 ** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
5975 ** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
5976 ** The mutex implementation does not need to make a distinction
5977 ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
5978 ** not want to. SQLite will only request a recursive mutex in
5979 ** cases where it really needs one. If a faster non-recursive mutex
5980 ** implementation is available on the host platform, the mutex subsystem
5981 ** might return such a mutex in response to SQLITE_MUTEX_FAST.
5983 ** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
5984 ** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
5985 ** a pointer to a static preexisting mutex. ^Nine static mutexes are
5986 ** used by the current version of SQLite. Future versions of SQLite
5987 ** may add additional static mutexes. Static mutexes are for internal
5988 ** use by SQLite only. Applications that use SQLite mutexes should
5989 ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
5990 ** SQLITE_MUTEX_RECURSIVE.
5992 ** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
5993 ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
5994 ** returns a different mutex on every call. ^For the static
5995 ** mutex types, the same mutex is returned on every call that has
5996 ** the same type number.
5998 ** ^The sqlite3_mutex_free() routine deallocates a previously
5999 ** allocated dynamic mutex. Attempting to deallocate a static
6000 ** mutex results in undefined behavior.
6002 ** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
6003 ** to enter a mutex. ^If another thread is already within the mutex,
6004 ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
6005 ** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
6006 ** upon successful entry. ^(Mutexes created using
6007 ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
6008 ** In such cases, the
6009 ** mutex must be exited an equal number of times before another thread
6010 ** can enter.)^ If the same thread tries to enter any mutex other
6011 ** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined.
6013 ** ^(Some systems (for example, Windows 95) do not support the operation
6014 ** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try()
6015 ** will always return SQLITE_BUSY. The SQLite core only ever uses
6016 ** sqlite3_mutex_try() as an optimization so this is acceptable
6019 ** ^The sqlite3_mutex_leave() routine exits a mutex that was
6020 ** previously entered by the same thread. The behavior
6021 ** is undefined if the mutex is not currently entered by the
6022 ** calling thread or is not currently allocated.
6024 ** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
6025 ** sqlite3_mutex_leave() is a NULL pointer, then all three routines
6026 ** behave as no-ops.
6028 ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
6030 SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int);
6031 SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*);
6032 SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*);
6033 SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*);
6034 SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*);
6037 ** CAPI3REF: Mutex Methods Object
6039 ** An instance of this structure defines the low-level routines
6040 ** used to allocate and use mutexes.
6042 ** Usually, the default mutex implementations provided by SQLite are
6043 ** sufficient, however the application has the option of substituting a custom
6044 ** implementation for specialized deployments or systems for which SQLite
6045 ** does not provide a suitable implementation. In this case, the application
6046 ** creates and populates an instance of this structure to pass
6047 ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
6048 ** Additionally, an instance of this structure can be used as an
6049 ** output variable when querying the system for the current mutex
6050 ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
6052 ** ^The xMutexInit method defined by this structure is invoked as
6053 ** part of system initialization by the sqlite3_initialize() function.
6054 ** ^The xMutexInit routine is called by SQLite exactly once for each
6055 ** effective call to [sqlite3_initialize()].
6057 ** ^The xMutexEnd method defined by this structure is invoked as
6058 ** part of system shutdown by the sqlite3_shutdown() function. The
6059 ** implementation of this method is expected to release all outstanding
6060 ** resources obtained by the mutex methods implementation, especially
6061 ** those obtained by the xMutexInit method. ^The xMutexEnd()
6062 ** interface is invoked exactly once for each call to [sqlite3_shutdown()].
6064 ** ^(The remaining seven methods defined by this structure (xMutexAlloc,
6065 ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
6066 ** xMutexNotheld) implement the following interfaces (respectively):
6069 ** <li> [sqlite3_mutex_alloc()] </li>
6070 ** <li> [sqlite3_mutex_free()] </li>
6071 ** <li> [sqlite3_mutex_enter()] </li>
6072 ** <li> [sqlite3_mutex_try()] </li>
6073 ** <li> [sqlite3_mutex_leave()] </li>
6074 ** <li> [sqlite3_mutex_held()] </li>
6075 ** <li> [sqlite3_mutex_notheld()] </li>
6078 ** The only difference is that the public sqlite3_XXX functions enumerated
6079 ** above silently ignore any invocations that pass a NULL pointer instead
6080 ** of a valid mutex handle. The implementations of the methods defined
6081 ** by this structure are not required to handle this case, the results
6082 ** of passing a NULL pointer instead of a valid mutex handle are undefined
6083 ** (i.e. it is acceptable to provide an implementation that segfaults if
6084 ** it is passed a NULL pointer).
6086 ** The xMutexInit() method must be threadsafe. It must be harmless to
6087 ** invoke xMutexInit() multiple times within the same process and without
6088 ** intervening calls to xMutexEnd(). Second and subsequent calls to
6089 ** xMutexInit() must be no-ops.
6091 ** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
6092 ** and its associates). Similarly, xMutexAlloc() must not use SQLite memory
6093 ** allocation for a static mutex. ^However xMutexAlloc() may use SQLite
6094 ** memory allocation for a fast or recursive mutex.
6096 ** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
6097 ** called, but only if the prior call to xMutexInit returned SQLITE_OK.
6098 ** If xMutexInit fails in any way, it is expected to clean up after itself
6099 ** prior to returning.
6101 typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
6102 struct sqlite3_mutex_methods {
6103 int (*xMutexInit)(void);
6104 int (*xMutexEnd)(void);
6105 sqlite3_mutex *(*xMutexAlloc)(int);
6106 void (*xMutexFree)(sqlite3_mutex *);
6107 void (*xMutexEnter)(sqlite3_mutex *);
6108 int (*xMutexTry)(sqlite3_mutex *);
6109 void (*xMutexLeave)(sqlite3_mutex *);
6110 int (*xMutexHeld)(sqlite3_mutex *);
6111 int (*xMutexNotheld)(sqlite3_mutex *);
6115 ** CAPI3REF: Mutex Verification Routines
6117 ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
6118 ** are intended for use inside assert() statements. The SQLite core
6119 ** never uses these routines except inside an assert() and applications
6120 ** are advised to follow the lead of the core. The SQLite core only
6121 ** provides implementations for these routines when it is compiled
6122 ** with the SQLITE_DEBUG flag. External mutex implementations
6123 ** are only required to provide these routines if SQLITE_DEBUG is
6124 ** defined and if NDEBUG is not defined.
6126 ** These routines should return true if the mutex in their argument
6127 ** is held or not held, respectively, by the calling thread.
6129 ** The implementation is not required to provide versions of these
6130 ** routines that actually work. If the implementation does not provide working
6131 ** versions of these routines, it should at least provide stubs that always
6132 ** return true so that one does not get spurious assertion failures.
6134 ** If the argument to sqlite3_mutex_held() is a NULL pointer then
6135 ** the routine should return 1. This seems counter-intuitive since
6136 ** clearly the mutex cannot be held if it does not exist. But
6137 ** the reason the mutex does not exist is because the build is not
6138 ** using mutexes. And we do not want the assert() containing the
6139 ** call to sqlite3_mutex_held() to fail, so a non-zero return is
6140 ** the appropriate thing to do. The sqlite3_mutex_notheld()
6141 ** interface should also return 1 when given a NULL pointer.
6144 SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*);
6145 SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*);
6149 ** CAPI3REF: Mutex Types
6151 ** The [sqlite3_mutex_alloc()] interface takes a single argument
6152 ** which is one of these integer constants.
6154 ** The set of static mutexes may change from one SQLite release to the
6155 ** next. Applications that override the built-in mutex logic must be
6156 ** prepared to accommodate additional static mutexes.
6158 #define SQLITE_MUTEX_FAST 0
6159 #define SQLITE_MUTEX_RECURSIVE 1
6160 #define SQLITE_MUTEX_STATIC_MASTER 2
6161 #define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */
6162 #define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */
6163 #define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */
6164 #define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */
6165 #define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */
6166 #define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */
6167 #define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */
6168 #define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */
6169 #define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */
6170 #define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */
6173 ** CAPI3REF: Retrieve the mutex for a database connection
6175 ** ^This interface returns a pointer the [sqlite3_mutex] object that
6176 ** serializes access to the [database connection] given in the argument
6177 ** when the [threading mode] is Serialized.
6178 ** ^If the [threading mode] is Single-thread or Multi-thread then this
6179 ** routine returns a NULL pointer.
6181 SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
6184 ** CAPI3REF: Low-Level Control Of Database Files
6186 ** ^The [sqlite3_file_control()] interface makes a direct call to the
6187 ** xFileControl method for the [sqlite3_io_methods] object associated
6188 ** with a particular database identified by the second argument. ^The
6189 ** name of the database is "main" for the main database or "temp" for the
6190 ** TEMP database, or the name that appears after the AS keyword for
6191 ** databases that are added using the [ATTACH] SQL command.
6192 ** ^A NULL pointer can be used in place of "main" to refer to the
6193 ** main database file.
6194 ** ^The third and fourth parameters to this routine
6195 ** are passed directly through to the second and third parameters of
6196 ** the xFileControl method. ^The return value of the xFileControl
6197 ** method becomes the return value of this routine.
6199 ** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes
6200 ** a pointer to the underlying [sqlite3_file] object to be written into
6201 ** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER
6202 ** case is a short-circuit path which does not actually invoke the
6203 ** underlying sqlite3_io_methods.xFileControl method.
6205 ** ^If the second parameter (zDbName) does not match the name of any
6206 ** open database file, then SQLITE_ERROR is returned. ^This error
6207 ** code is not remembered and will not be recalled by [sqlite3_errcode()]
6208 ** or [sqlite3_errmsg()]. The underlying xFileControl method might
6209 ** also return SQLITE_ERROR. There is no way to distinguish between
6210 ** an incorrect zDbName and an SQLITE_ERROR return from the underlying
6211 ** xFileControl method.
6213 ** See also: [SQLITE_FCNTL_LOCKSTATE]
6215 SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
6218 ** CAPI3REF: Testing Interface
6220 ** ^The sqlite3_test_control() interface is used to read out internal
6221 ** state of SQLite and to inject faults into SQLite for testing
6222 ** purposes. ^The first parameter is an operation code that determines
6223 ** the number, meaning, and operation of all subsequent parameters.
6225 ** This interface is not for use by applications. It exists solely
6226 ** for verifying the correct operation of the SQLite library. Depending
6227 ** on how the SQLite library is compiled, this interface might not exist.
6229 ** The details of the operation codes, their meanings, the parameters
6230 ** they take, and what they do are all subject to change without notice.
6231 ** Unlike most of the SQLite API, this function is not guaranteed to
6232 ** operate consistently from one release to the next.
6234 SQLITE_API int sqlite3_test_control(int op, ...);
6237 ** CAPI3REF: Testing Interface Operation Codes
6239 ** These constants are the valid operation code parameters used
6240 ** as the first argument to [sqlite3_test_control()].
6242 ** These parameters and their meanings are subject to change
6243 ** without notice. These values are for testing purposes only.
6244 ** Applications should not use any of these parameters or the
6245 ** [sqlite3_test_control()] interface.
6247 #define SQLITE_TESTCTRL_FIRST 5
6248 #define SQLITE_TESTCTRL_PRNG_SAVE 5
6249 #define SQLITE_TESTCTRL_PRNG_RESTORE 6
6250 #define SQLITE_TESTCTRL_PRNG_RESET 7
6251 #define SQLITE_TESTCTRL_BITVEC_TEST 8
6252 #define SQLITE_TESTCTRL_FAULT_INSTALL 9
6253 #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10
6254 #define SQLITE_TESTCTRL_PENDING_BYTE 11
6255 #define SQLITE_TESTCTRL_ASSERT 12
6256 #define SQLITE_TESTCTRL_ALWAYS 13
6257 #define SQLITE_TESTCTRL_RESERVE 14
6258 #define SQLITE_TESTCTRL_OPTIMIZATIONS 15
6259 #define SQLITE_TESTCTRL_ISKEYWORD 16
6260 #define SQLITE_TESTCTRL_SCRATCHMALLOC 17
6261 #define SQLITE_TESTCTRL_LOCALTIME_FAULT 18
6262 #define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */
6263 #define SQLITE_TESTCTRL_NEVER_CORRUPT 20
6264 #define SQLITE_TESTCTRL_VDBE_COVERAGE 21
6265 #define SQLITE_TESTCTRL_BYTEORDER 22
6266 #define SQLITE_TESTCTRL_ISINIT 23
6267 #define SQLITE_TESTCTRL_SORTER_MMAP 24
6268 #define SQLITE_TESTCTRL_LAST 24
6271 ** CAPI3REF: SQLite Runtime Status
6273 ** ^This interface is used to retrieve runtime status information
6274 ** about the performance of SQLite, and optionally to reset various
6275 ** highwater marks. ^The first argument is an integer code for
6276 ** the specific parameter to measure. ^(Recognized integer codes
6277 ** are of the form [status parameters | SQLITE_STATUS_...].)^
6278 ** ^The current value of the parameter is returned into *pCurrent.
6279 ** ^The highest recorded value is returned in *pHighwater. ^If the
6280 ** resetFlag is true, then the highest record value is reset after
6281 ** *pHighwater is written. ^(Some parameters do not record the highest
6282 ** value. For those parameters
6283 ** nothing is written into *pHighwater and the resetFlag is ignored.)^
6284 ** ^(Other parameters record only the highwater mark and not the current
6285 ** value. For these latter parameters nothing is written into *pCurrent.)^
6287 ** ^The sqlite3_status() routine returns SQLITE_OK on success and a
6288 ** non-zero [error code] on failure.
6290 ** This routine is threadsafe but is not atomic. This routine can be
6291 ** called while other threads are running the same or different SQLite
6292 ** interfaces. However the values returned in *pCurrent and
6293 ** *pHighwater reflect the status of SQLite at different points in time
6294 ** and it is possible that another thread might change the parameter
6295 ** in between the times when *pCurrent and *pHighwater are written.
6297 ** See also: [sqlite3_db_status()]
6299 SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
6303 ** CAPI3REF: Status Parameters
6304 ** KEYWORDS: {status parameters}
6306 ** These integer constants designate various run-time status parameters
6307 ** that can be returned by [sqlite3_status()].
6310 ** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
6311 ** <dd>This parameter is the current amount of memory checked out
6312 ** using [sqlite3_malloc()], either directly or indirectly. The
6313 ** figure includes calls made to [sqlite3_malloc()] by the application
6314 ** and internal memory usage by the SQLite library. Scratch memory
6315 ** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache
6316 ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
6317 ** this parameter. The amount returned is the sum of the allocation
6318 ** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
6320 ** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
6321 ** <dd>This parameter records the largest memory allocation request
6322 ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
6323 ** internal equivalents). Only the value returned in the
6324 ** *pHighwater parameter to [sqlite3_status()] is of interest.
6325 ** The value written into the *pCurrent parameter is undefined.</dd>)^
6327 ** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
6328 ** <dd>This parameter records the number of separate memory allocations
6329 ** currently checked out.</dd>)^
6331 ** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
6332 ** <dd>This parameter returns the number of pages used out of the
6333 ** [pagecache memory allocator] that was configured using
6334 ** [SQLITE_CONFIG_PAGECACHE]. The
6335 ** value returned is in pages, not in bytes.</dd>)^
6337 ** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]]
6338 ** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
6339 ** <dd>This parameter returns the number of bytes of page cache
6340 ** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
6341 ** buffer and where forced to overflow to [sqlite3_malloc()]. The
6342 ** returned value includes allocations that overflowed because they
6343 ** where too large (they were larger than the "sz" parameter to
6344 ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
6345 ** no space was left in the page cache.</dd>)^
6347 ** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
6348 ** <dd>This parameter records the largest memory allocation request
6349 ** handed to [pagecache memory allocator]. Only the value returned in the
6350 ** *pHighwater parameter to [sqlite3_status()] is of interest.
6351 ** The value written into the *pCurrent parameter is undefined.</dd>)^
6353 ** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt>
6354 ** <dd>This parameter returns the number of allocations used out of the
6355 ** [scratch memory allocator] configured using
6356 ** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not
6357 ** in bytes. Since a single thread may only have one scratch allocation
6358 ** outstanding at time, this parameter also reports the number of threads
6359 ** using scratch memory at the same time.</dd>)^
6361 ** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
6362 ** <dd>This parameter returns the number of bytes of scratch memory
6363 ** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH]
6364 ** buffer and where forced to overflow to [sqlite3_malloc()]. The values
6365 ** returned include overflows because the requested allocation was too
6366 ** larger (that is, because the requested allocation was larger than the
6367 ** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer
6368 ** slots were available.
6371 ** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
6372 ** <dd>This parameter records the largest memory allocation request
6373 ** handed to [scratch memory allocator]. Only the value returned in the
6374 ** *pHighwater parameter to [sqlite3_status()] is of interest.
6375 ** The value written into the *pCurrent parameter is undefined.</dd>)^
6377 ** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
6378 ** <dd>This parameter records the deepest parser stack. It is only
6379 ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
6382 ** New status parameters may be added from time to time.
6384 #define SQLITE_STATUS_MEMORY_USED 0
6385 #define SQLITE_STATUS_PAGECACHE_USED 1
6386 #define SQLITE_STATUS_PAGECACHE_OVERFLOW 2
6387 #define SQLITE_STATUS_SCRATCH_USED 3
6388 #define SQLITE_STATUS_SCRATCH_OVERFLOW 4
6389 #define SQLITE_STATUS_MALLOC_SIZE 5
6390 #define SQLITE_STATUS_PARSER_STACK 6
6391 #define SQLITE_STATUS_PAGECACHE_SIZE 7
6392 #define SQLITE_STATUS_SCRATCH_SIZE 8
6393 #define SQLITE_STATUS_MALLOC_COUNT 9
6396 ** CAPI3REF: Database Connection Status
6398 ** ^This interface is used to retrieve runtime status information
6399 ** about a single [database connection]. ^The first argument is the
6400 ** database connection object to be interrogated. ^The second argument
6401 ** is an integer constant, taken from the set of
6402 ** [SQLITE_DBSTATUS options], that
6403 ** determines the parameter to interrogate. The set of
6404 ** [SQLITE_DBSTATUS options] is likely
6405 ** to grow in future releases of SQLite.
6407 ** ^The current value of the requested parameter is written into *pCur
6408 ** and the highest instantaneous value is written into *pHiwtr. ^If
6409 ** the resetFlg is true, then the highest instantaneous value is
6410 ** reset back down to the current value.
6412 ** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
6413 ** non-zero [error code] on failure.
6415 ** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
6417 SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
6420 ** CAPI3REF: Status Parameters for database connections
6421 ** KEYWORDS: {SQLITE_DBSTATUS options}
6423 ** These constants are the available integer "verbs" that can be passed as
6424 ** the second argument to the [sqlite3_db_status()] interface.
6426 ** New verbs may be added in future releases of SQLite. Existing verbs
6427 ** might be discontinued. Applications should check the return code from
6428 ** [sqlite3_db_status()] to make sure that the call worked.
6429 ** The [sqlite3_db_status()] interface will return a non-zero error code
6430 ** if a discontinued or unsupported verb is invoked.
6433 ** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
6434 ** <dd>This parameter returns the number of lookaside memory slots currently
6435 ** checked out.</dd>)^
6437 ** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
6438 ** <dd>This parameter returns the number malloc attempts that were
6439 ** satisfied using lookaside memory. Only the high-water value is meaningful;
6440 ** the current value is always zero.)^
6442 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]]
6443 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
6444 ** <dd>This parameter returns the number malloc attempts that might have
6445 ** been satisfied using lookaside memory but failed due to the amount of
6446 ** memory requested being larger than the lookaside slot size.
6447 ** Only the high-water value is meaningful;
6448 ** the current value is always zero.)^
6450 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]]
6451 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
6452 ** <dd>This parameter returns the number malloc attempts that might have
6453 ** been satisfied using lookaside memory but failed due to all lookaside
6454 ** memory already being in use.
6455 ** Only the high-water value is meaningful;
6456 ** the current value is always zero.)^
6458 ** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
6459 ** <dd>This parameter returns the approximate number of bytes of heap
6460 ** memory used by all pager caches associated with the database connection.)^
6461 ** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
6463 ** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
6464 ** <dd>This parameter returns the approximate number of bytes of heap
6465 ** memory used to store the schema for all databases associated
6466 ** with the connection - main, temp, and any [ATTACH]-ed databases.)^
6467 ** ^The full amount of memory used by the schemas is reported, even if the
6468 ** schema memory is shared with other database connections due to
6469 ** [shared cache mode] being enabled.
6470 ** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
6472 ** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
6473 ** <dd>This parameter returns the approximate number of bytes of heap
6474 ** and lookaside memory used by all prepared statements associated with
6475 ** the database connection.)^
6476 ** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
6479 ** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt>
6480 ** <dd>This parameter returns the number of pager cache hits that have
6481 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT
6485 ** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt>
6486 ** <dd>This parameter returns the number of pager cache misses that have
6487 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS
6491 ** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt>
6492 ** <dd>This parameter returns the number of dirty cache entries that have
6493 ** been written to disk. Specifically, the number of pages written to the
6494 ** wal file in wal mode databases, or the number of pages written to the
6495 ** database file in rollback mode databases. Any pages written as part of
6496 ** transaction rollback or database recovery operations are not included.
6497 ** If an IO or other error occurs while writing a page to disk, the effect
6498 ** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The
6499 ** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0.
6502 ** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt>
6503 ** <dd>This parameter returns zero for the current value if and only if
6504 ** all foreign key constraints (deferred or immediate) have been
6505 ** resolved.)^ ^The highwater mark is always 0.
6509 #define SQLITE_DBSTATUS_LOOKASIDE_USED 0
6510 #define SQLITE_DBSTATUS_CACHE_USED 1
6511 #define SQLITE_DBSTATUS_SCHEMA_USED 2
6512 #define SQLITE_DBSTATUS_STMT_USED 3
6513 #define SQLITE_DBSTATUS_LOOKASIDE_HIT 4
6514 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5
6515 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6
6516 #define SQLITE_DBSTATUS_CACHE_HIT 7
6517 #define SQLITE_DBSTATUS_CACHE_MISS 8
6518 #define SQLITE_DBSTATUS_CACHE_WRITE 9
6519 #define SQLITE_DBSTATUS_DEFERRED_FKS 10
6520 #define SQLITE_DBSTATUS_MAX 10 /* Largest defined DBSTATUS */
6524 ** CAPI3REF: Prepared Statement Status
6526 ** ^(Each prepared statement maintains various
6527 ** [SQLITE_STMTSTATUS counters] that measure the number
6528 ** of times it has performed specific operations.)^ These counters can
6529 ** be used to monitor the performance characteristics of the prepared
6530 ** statements. For example, if the number of table steps greatly exceeds
6531 ** the number of table searches or result rows, that would tend to indicate
6532 ** that the prepared statement is using a full table scan rather than
6535 ** ^(This interface is used to retrieve and reset counter values from
6536 ** a [prepared statement]. The first argument is the prepared statement
6537 ** object to be interrogated. The second argument
6538 ** is an integer code for a specific [SQLITE_STMTSTATUS counter]
6539 ** to be interrogated.)^
6540 ** ^The current value of the requested counter is returned.
6541 ** ^If the resetFlg is true, then the counter is reset to zero after this
6542 ** interface call returns.
6544 ** See also: [sqlite3_status()] and [sqlite3_db_status()].
6546 SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
6549 ** CAPI3REF: Status Parameters for prepared statements
6550 ** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters}
6552 ** These preprocessor macros define integer codes that name counter
6553 ** values associated with the [sqlite3_stmt_status()] interface.
6554 ** The meanings of the various counters are as follows:
6557 ** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
6558 ** <dd>^This is the number of times that SQLite has stepped forward in
6559 ** a table as part of a full table scan. Large numbers for this counter
6560 ** may indicate opportunities for performance improvement through
6561 ** careful use of indices.</dd>
6563 ** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt>
6564 ** <dd>^This is the number of sort operations that have occurred.
6565 ** A non-zero value in this counter may indicate an opportunity to
6566 ** improvement performance through careful use of indices.</dd>
6568 ** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
6569 ** <dd>^This is the number of rows inserted into transient indices that
6570 ** were created automatically in order to help joins run faster.
6571 ** A non-zero value in this counter may indicate an opportunity to
6572 ** improvement performance by adding permanent indices that do not
6573 ** need to be reinitialized each time the statement is run.</dd>
6575 ** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt>
6576 ** <dd>^This is the number of virtual machine operations executed
6577 ** by the prepared statement if that number is less than or equal
6578 ** to 2147483647. The number of virtual machine operations can be
6579 ** used as a proxy for the total work done by the prepared statement.
6580 ** If the number of virtual machine operations exceeds 2147483647
6581 ** then the value returned by this statement status code is undefined.
6585 #define SQLITE_STMTSTATUS_FULLSCAN_STEP 1
6586 #define SQLITE_STMTSTATUS_SORT 2
6587 #define SQLITE_STMTSTATUS_AUTOINDEX 3
6588 #define SQLITE_STMTSTATUS_VM_STEP 4
6591 ** CAPI3REF: Custom Page Cache Object
6593 ** The sqlite3_pcache type is opaque. It is implemented by
6594 ** the pluggable module. The SQLite core has no knowledge of
6595 ** its size or internal structure and never deals with the
6596 ** sqlite3_pcache object except by holding and passing pointers
6599 ** See [sqlite3_pcache_methods2] for additional information.
6601 typedef struct sqlite3_pcache sqlite3_pcache;
6604 ** CAPI3REF: Custom Page Cache Object
6606 ** The sqlite3_pcache_page object represents a single page in the
6607 ** page cache. The page cache will allocate instances of this
6608 ** object. Various methods of the page cache use pointers to instances
6609 ** of this object as parameters or as their return value.
6611 ** See [sqlite3_pcache_methods2] for additional information.
6613 typedef struct sqlite3_pcache_page sqlite3_pcache_page;
6614 struct sqlite3_pcache_page {
6615 void *pBuf; /* The content of the page */
6616 void *pExtra; /* Extra information associated with the page */
6620 ** CAPI3REF: Application Defined Page Cache.
6621 ** KEYWORDS: {page cache}
6623 ** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can
6624 ** register an alternative page cache implementation by passing in an
6625 ** instance of the sqlite3_pcache_methods2 structure.)^
6626 ** In many applications, most of the heap memory allocated by
6627 ** SQLite is used for the page cache.
6628 ** By implementing a
6629 ** custom page cache using this API, an application can better control
6630 ** the amount of memory consumed by SQLite, the way in which
6631 ** that memory is allocated and released, and the policies used to
6632 ** determine exactly which parts of a database file are cached and for
6635 ** The alternative page cache mechanism is an
6636 ** extreme measure that is only needed by the most demanding applications.
6637 ** The built-in page cache is recommended for most uses.
6639 ** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an
6640 ** internal buffer by SQLite within the call to [sqlite3_config]. Hence
6641 ** the application may discard the parameter after the call to
6642 ** [sqlite3_config()] returns.)^
6644 ** [[the xInit() page cache method]]
6645 ** ^(The xInit() method is called once for each effective
6646 ** call to [sqlite3_initialize()])^
6647 ** (usually only once during the lifetime of the process). ^(The xInit()
6648 ** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^
6649 ** The intent of the xInit() method is to set up global data structures
6650 ** required by the custom page cache implementation.
6651 ** ^(If the xInit() method is NULL, then the
6652 ** built-in default page cache is used instead of the application defined
6655 ** [[the xShutdown() page cache method]]
6656 ** ^The xShutdown() method is called by [sqlite3_shutdown()].
6657 ** It can be used to clean up
6658 ** any outstanding resources before process shutdown, if required.
6659 ** ^The xShutdown() method may be NULL.
6661 ** ^SQLite automatically serializes calls to the xInit method,
6662 ** so the xInit method need not be threadsafe. ^The
6663 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
6664 ** not need to be threadsafe either. All other methods must be threadsafe
6665 ** in multithreaded applications.
6667 ** ^SQLite will never invoke xInit() more than once without an intervening
6668 ** call to xShutdown().
6670 ** [[the xCreate() page cache methods]]
6671 ** ^SQLite invokes the xCreate() method to construct a new cache instance.
6672 ** SQLite will typically create one cache instance for each open database file,
6673 ** though this is not guaranteed. ^The
6674 ** first parameter, szPage, is the size in bytes of the pages that must
6675 ** be allocated by the cache. ^szPage will always a power of two. ^The
6676 ** second parameter szExtra is a number of bytes of extra storage
6677 ** associated with each page cache entry. ^The szExtra parameter will
6678 ** a number less than 250. SQLite will use the
6679 ** extra szExtra bytes on each page to store metadata about the underlying
6680 ** database page on disk. The value passed into szExtra depends
6681 ** on the SQLite version, the target platform, and how SQLite was compiled.
6682 ** ^The third argument to xCreate(), bPurgeable, is true if the cache being
6683 ** created will be used to cache database pages of a file stored on disk, or
6684 ** false if it is used for an in-memory database. The cache implementation
6685 ** does not have to do anything special based with the value of bPurgeable;
6686 ** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will
6687 ** never invoke xUnpin() except to deliberately delete a page.
6688 ** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
6689 ** false will always have the "discard" flag set to true.
6690 ** ^Hence, a cache created with bPurgeable false will
6691 ** never contain any unpinned pages.
6693 ** [[the xCachesize() page cache method]]
6694 ** ^(The xCachesize() method may be called at any time by SQLite to set the
6695 ** suggested maximum cache-size (number of pages stored by) the cache
6696 ** instance passed as the first argument. This is the value configured using
6697 ** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable
6698 ** parameter, the implementation is not required to do anything with this
6699 ** value; it is advisory only.
6701 ** [[the xPagecount() page cache methods]]
6702 ** The xPagecount() method must return the number of pages currently
6703 ** stored in the cache, both pinned and unpinned.
6705 ** [[the xFetch() page cache methods]]
6706 ** The xFetch() method locates a page in the cache and returns a pointer to
6707 ** an sqlite3_pcache_page object associated with that page, or a NULL pointer.
6708 ** The pBuf element of the returned sqlite3_pcache_page object will be a
6709 ** pointer to a buffer of szPage bytes used to store the content of a
6710 ** single database page. The pExtra element of sqlite3_pcache_page will be
6711 ** a pointer to the szExtra bytes of extra storage that SQLite has requested
6712 ** for each entry in the page cache.
6714 ** The page to be fetched is determined by the key. ^The minimum key value
6715 ** is 1. After it has been retrieved using xFetch, the page is considered
6718 ** If the requested page is already in the page cache, then the page cache
6719 ** implementation must return a pointer to the page buffer with its content
6720 ** intact. If the requested page is not already in the cache, then the
6721 ** cache implementation should use the value of the createFlag
6722 ** parameter to help it determined what action to take:
6724 ** <table border=1 width=85% align=center>
6725 ** <tr><th> createFlag <th> Behavior when page is not already in cache
6726 ** <tr><td> 0 <td> Do not allocate a new page. Return NULL.
6727 ** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
6728 ** Otherwise return NULL.
6729 ** <tr><td> 2 <td> Make every effort to allocate a new page. Only return
6730 ** NULL if allocating a new page is effectively impossible.
6733 ** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite
6734 ** will only use a createFlag of 2 after a prior call with a createFlag of 1
6735 ** failed.)^ In between the to xFetch() calls, SQLite may
6736 ** attempt to unpin one or more cache pages by spilling the content of
6737 ** pinned pages to disk and synching the operating system disk cache.
6739 ** [[the xUnpin() page cache method]]
6740 ** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
6741 ** as its second argument. If the third parameter, discard, is non-zero,
6742 ** then the page must be evicted from the cache.
6743 ** ^If the discard parameter is
6744 ** zero, then the page may be discarded or retained at the discretion of
6745 ** page cache implementation. ^The page cache implementation
6746 ** may choose to evict unpinned pages at any time.
6748 ** The cache must not perform any reference counting. A single
6749 ** call to xUnpin() unpins the page regardless of the number of prior calls
6752 ** [[the xRekey() page cache methods]]
6753 ** The xRekey() method is used to change the key value associated with the
6754 ** page passed as the second argument. If the cache
6755 ** previously contains an entry associated with newKey, it must be
6756 ** discarded. ^Any prior cache entry associated with newKey is guaranteed not
6759 ** When SQLite calls the xTruncate() method, the cache must discard all
6760 ** existing cache entries with page numbers (keys) greater than or equal
6761 ** to the value of the iLimit parameter passed to xTruncate(). If any
6762 ** of these pages are pinned, they are implicitly unpinned, meaning that
6763 ** they can be safely discarded.
6765 ** [[the xDestroy() page cache method]]
6766 ** ^The xDestroy() method is used to delete a cache allocated by xCreate().
6767 ** All resources associated with the specified cache should be freed. ^After
6768 ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
6769 ** handle invalid, and will not use it with any other sqlite3_pcache_methods2
6772 ** [[the xShrink() page cache method]]
6773 ** ^SQLite invokes the xShrink() method when it wants the page cache to
6774 ** free up as much of heap memory as possible. The page cache implementation
6775 ** is not obligated to free any memory, but well-behaved implementations should
6778 typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
6779 struct sqlite3_pcache_methods2 {
6782 int (*xInit)(void*);
6783 void (*xShutdown)(void*);
6784 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
6785 void (*xCachesize)(sqlite3_pcache*, int nCachesize);
6786 int (*xPagecount)(sqlite3_pcache*);
6787 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
6788 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
6789 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*,
6790 unsigned oldKey, unsigned newKey);
6791 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
6792 void (*xDestroy)(sqlite3_pcache*);
6793 void (*xShrink)(sqlite3_pcache*);
6797 ** This is the obsolete pcache_methods object that has now been replaced
6798 ** by sqlite3_pcache_methods2. This object is not used by SQLite. It is
6799 ** retained in the header file for backwards compatibility only.
6801 typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
6802 struct sqlite3_pcache_methods {
6804 int (*xInit)(void*);
6805 void (*xShutdown)(void*);
6806 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
6807 void (*xCachesize)(sqlite3_pcache*, int nCachesize);
6808 int (*xPagecount)(sqlite3_pcache*);
6809 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
6810 void (*xUnpin)(sqlite3_pcache*, void*, int discard);
6811 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
6812 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
6813 void (*xDestroy)(sqlite3_pcache*);
6818 ** CAPI3REF: Online Backup Object
6820 ** The sqlite3_backup object records state information about an ongoing
6821 ** online backup operation. ^The sqlite3_backup object is created by
6822 ** a call to [sqlite3_backup_init()] and is destroyed by a call to
6823 ** [sqlite3_backup_finish()].
6825 ** See Also: [Using the SQLite Online Backup API]
6827 typedef struct sqlite3_backup sqlite3_backup;
6830 ** CAPI3REF: Online Backup API.
6832 ** The backup API copies the content of one database into another.
6833 ** It is useful either for creating backups of databases or
6834 ** for copying in-memory databases to or from persistent files.
6836 ** See Also: [Using the SQLite Online Backup API]
6838 ** ^SQLite holds a write transaction open on the destination database file
6839 ** for the duration of the backup operation.
6840 ** ^The source database is read-locked only while it is being read;
6841 ** it is not locked continuously for the entire backup operation.
6842 ** ^Thus, the backup may be performed on a live source database without
6843 ** preventing other database connections from
6844 ** reading or writing to the source database while the backup is underway.
6846 ** ^(To perform a backup operation:
6848 ** <li><b>sqlite3_backup_init()</b> is called once to initialize the
6850 ** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
6851 ** the data between the two databases, and finally
6852 ** <li><b>sqlite3_backup_finish()</b> is called to release all resources
6853 ** associated with the backup operation.
6855 ** There should be exactly one call to sqlite3_backup_finish() for each
6856 ** successful call to sqlite3_backup_init().
6858 ** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
6860 ** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
6861 ** [database connection] associated with the destination database
6862 ** and the database name, respectively.
6863 ** ^The database name is "main" for the main database, "temp" for the
6864 ** temporary database, or the name specified after the AS keyword in
6865 ** an [ATTACH] statement for an attached database.
6866 ** ^The S and M arguments passed to
6867 ** sqlite3_backup_init(D,N,S,M) identify the [database connection]
6868 ** and database name of the source database, respectively.
6869 ** ^The source and destination [database connections] (parameters S and D)
6870 ** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
6873 ** ^A call to sqlite3_backup_init() will fail, returning SQLITE_ERROR, if
6874 ** there is already a read or read-write transaction open on the
6875 ** destination database.
6877 ** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
6878 ** returned and an error code and error message are stored in the
6879 ** destination [database connection] D.
6880 ** ^The error code and message for the failed call to sqlite3_backup_init()
6881 ** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
6882 ** [sqlite3_errmsg16()] functions.
6883 ** ^A successful call to sqlite3_backup_init() returns a pointer to an
6884 ** [sqlite3_backup] object.
6885 ** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
6886 ** sqlite3_backup_finish() functions to perform the specified backup
6889 ** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
6891 ** ^Function sqlite3_backup_step(B,N) will copy up to N pages between
6892 ** the source and destination databases specified by [sqlite3_backup] object B.
6893 ** ^If N is negative, all remaining source pages are copied.
6894 ** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
6895 ** are still more pages to be copied, then the function returns [SQLITE_OK].
6896 ** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
6897 ** from source to destination, then it returns [SQLITE_DONE].
6898 ** ^If an error occurs while running sqlite3_backup_step(B,N),
6899 ** then an [error code] is returned. ^As well as [SQLITE_OK] and
6900 ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
6901 ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
6902 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
6904 ** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
6906 ** <li> the destination database was opened read-only, or
6907 ** <li> the destination database is using write-ahead-log journaling
6908 ** and the destination and source page sizes differ, or
6909 ** <li> the destination database is an in-memory database and the
6910 ** destination and source page sizes differ.
6913 ** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
6914 ** the [sqlite3_busy_handler | busy-handler function]
6915 ** is invoked (if one is specified). ^If the
6916 ** busy-handler returns non-zero before the lock is available, then
6917 ** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
6918 ** sqlite3_backup_step() can be retried later. ^If the source
6919 ** [database connection]
6920 ** is being used to write to the source database when sqlite3_backup_step()
6921 ** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
6922 ** case the call to sqlite3_backup_step() can be retried later on. ^(If
6923 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
6924 ** [SQLITE_READONLY] is returned, then
6925 ** there is no point in retrying the call to sqlite3_backup_step(). These
6926 ** errors are considered fatal.)^ The application must accept
6927 ** that the backup operation has failed and pass the backup operation handle
6928 ** to the sqlite3_backup_finish() to release associated resources.
6930 ** ^The first call to sqlite3_backup_step() obtains an exclusive lock
6931 ** on the destination file. ^The exclusive lock is not released until either
6932 ** sqlite3_backup_finish() is called or the backup operation is complete
6933 ** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to
6934 ** sqlite3_backup_step() obtains a [shared lock] on the source database that
6935 ** lasts for the duration of the sqlite3_backup_step() call.
6936 ** ^Because the source database is not locked between calls to
6937 ** sqlite3_backup_step(), the source database may be modified mid-way
6938 ** through the backup process. ^If the source database is modified by an
6939 ** external process or via a database connection other than the one being
6940 ** used by the backup operation, then the backup will be automatically
6941 ** restarted by the next call to sqlite3_backup_step(). ^If the source
6942 ** database is modified by the using the same database connection as is used
6943 ** by the backup operation, then the backup database is automatically
6944 ** updated at the same time.
6946 ** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
6948 ** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the
6949 ** application wishes to abandon the backup operation, the application
6950 ** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
6951 ** ^The sqlite3_backup_finish() interfaces releases all
6952 ** resources associated with the [sqlite3_backup] object.
6953 ** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
6954 ** active write-transaction on the destination database is rolled back.
6955 ** The [sqlite3_backup] object is invalid
6956 ** and may not be used following a call to sqlite3_backup_finish().
6958 ** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
6959 ** sqlite3_backup_step() errors occurred, regardless or whether or not
6960 ** sqlite3_backup_step() completed.
6961 ** ^If an out-of-memory condition or IO error occurred during any prior
6962 ** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
6963 ** sqlite3_backup_finish() returns the corresponding [error code].
6965 ** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
6966 ** is not a permanent error and does not affect the return value of
6967 ** sqlite3_backup_finish().
6969 ** [[sqlite3_backup__remaining()]] [[sqlite3_backup_pagecount()]]
6970 ** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
6972 ** ^Each call to sqlite3_backup_step() sets two values inside
6973 ** the [sqlite3_backup] object: the number of pages still to be backed
6974 ** up and the total number of pages in the source database file.
6975 ** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces
6976 ** retrieve these two values, respectively.
6978 ** ^The values returned by these functions are only updated by
6979 ** sqlite3_backup_step(). ^If the source database is modified during a backup
6980 ** operation, then the values are not updated to account for any extra
6981 ** pages that need to be updated or the size of the source database file
6984 ** <b>Concurrent Usage of Database Handles</b>
6986 ** ^The source [database connection] may be used by the application for other
6987 ** purposes while a backup operation is underway or being initialized.
6988 ** ^If SQLite is compiled and configured to support threadsafe database
6989 ** connections, then the source database connection may be used concurrently
6990 ** from within other threads.
6992 ** However, the application must guarantee that the destination
6993 ** [database connection] is not passed to any other API (by any thread) after
6994 ** sqlite3_backup_init() is called and before the corresponding call to
6995 ** sqlite3_backup_finish(). SQLite does not currently check to see
6996 ** if the application incorrectly accesses the destination [database connection]
6997 ** and so no error code is reported, but the operations may malfunction
6998 ** nevertheless. Use of the destination database connection while a
6999 ** backup is in progress might also also cause a mutex deadlock.
7001 ** If running in [shared cache mode], the application must
7002 ** guarantee that the shared cache used by the destination database
7003 ** is not accessed while the backup is running. In practice this means
7004 ** that the application must guarantee that the disk file being
7005 ** backed up to is not accessed by any connection within the process,
7006 ** not just the specific connection that was passed to sqlite3_backup_init().
7008 ** The [sqlite3_backup] object itself is partially threadsafe. Multiple
7009 ** threads may safely make multiple concurrent calls to sqlite3_backup_step().
7010 ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
7011 ** APIs are not strictly speaking threadsafe. If they are invoked at the
7012 ** same time as another thread is invoking sqlite3_backup_step() it is
7013 ** possible that they return invalid values.
7015 SQLITE_API sqlite3_backup *sqlite3_backup_init(
7016 sqlite3 *pDest, /* Destination database handle */
7017 const char *zDestName, /* Destination database name */
7018 sqlite3 *pSource, /* Source database handle */
7019 const char *zSourceName /* Source database name */
7021 SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage);
7022 SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p);
7023 SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p);
7024 SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p);
7027 ** CAPI3REF: Unlock Notification
7029 ** ^When running in shared-cache mode, a database operation may fail with
7030 ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
7031 ** individual tables within the shared-cache cannot be obtained. See
7032 ** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
7033 ** ^This API may be used to register a callback that SQLite will invoke
7034 ** when the connection currently holding the required lock relinquishes it.
7035 ** ^This API is only available if the library was compiled with the
7036 ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
7038 ** See Also: [Using the SQLite Unlock Notification Feature].
7040 ** ^Shared-cache locks are released when a database connection concludes
7041 ** its current transaction, either by committing it or rolling it back.
7043 ** ^When a connection (known as the blocked connection) fails to obtain a
7044 ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
7045 ** identity of the database connection (the blocking connection) that
7046 ** has locked the required resource is stored internally. ^After an
7047 ** application receives an SQLITE_LOCKED error, it may call the
7048 ** sqlite3_unlock_notify() method with the blocked connection handle as
7049 ** the first argument to register for a callback that will be invoked
7050 ** when the blocking connections current transaction is concluded. ^The
7051 ** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
7052 ** call that concludes the blocking connections transaction.
7054 ** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
7055 ** there is a chance that the blocking connection will have already
7056 ** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
7057 ** If this happens, then the specified callback is invoked immediately,
7058 ** from within the call to sqlite3_unlock_notify().)^
7060 ** ^If the blocked connection is attempting to obtain a write-lock on a
7061 ** shared-cache table, and more than one other connection currently holds
7062 ** a read-lock on the same table, then SQLite arbitrarily selects one of
7063 ** the other connections to use as the blocking connection.
7065 ** ^(There may be at most one unlock-notify callback registered by a
7066 ** blocked connection. If sqlite3_unlock_notify() is called when the
7067 ** blocked connection already has a registered unlock-notify callback,
7068 ** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
7069 ** called with a NULL pointer as its second argument, then any existing
7070 ** unlock-notify callback is canceled. ^The blocked connections
7071 ** unlock-notify callback may also be canceled by closing the blocked
7072 ** connection using [sqlite3_close()].
7074 ** The unlock-notify callback is not reentrant. If an application invokes
7075 ** any sqlite3_xxx API functions from within an unlock-notify callback, a
7076 ** crash or deadlock may be the result.
7078 ** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
7079 ** returns SQLITE_OK.
7081 ** <b>Callback Invocation Details</b>
7083 ** When an unlock-notify callback is registered, the application provides a
7084 ** single void* pointer that is passed to the callback when it is invoked.
7085 ** However, the signature of the callback function allows SQLite to pass
7086 ** it an array of void* context pointers. The first argument passed to
7087 ** an unlock-notify callback is a pointer to an array of void* pointers,
7088 ** and the second is the number of entries in the array.
7090 ** When a blocking connections transaction is concluded, there may be
7091 ** more than one blocked connection that has registered for an unlock-notify
7092 ** callback. ^If two or more such blocked connections have specified the
7093 ** same callback function, then instead of invoking the callback function
7094 ** multiple times, it is invoked once with the set of void* context pointers
7095 ** specified by the blocked connections bundled together into an array.
7096 ** This gives the application an opportunity to prioritize any actions
7097 ** related to the set of unblocked database connections.
7099 ** <b>Deadlock Detection</b>
7101 ** Assuming that after registering for an unlock-notify callback a
7102 ** database waits for the callback to be issued before taking any further
7103 ** action (a reasonable assumption), then using this API may cause the
7104 ** application to deadlock. For example, if connection X is waiting for
7105 ** connection Y's transaction to be concluded, and similarly connection
7106 ** Y is waiting on connection X's transaction, then neither connection
7107 ** will proceed and the system may remain deadlocked indefinitely.
7109 ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
7110 ** detection. ^If a given call to sqlite3_unlock_notify() would put the
7111 ** system in a deadlocked state, then SQLITE_LOCKED is returned and no
7112 ** unlock-notify callback is registered. The system is said to be in
7113 ** a deadlocked state if connection A has registered for an unlock-notify
7114 ** callback on the conclusion of connection B's transaction, and connection
7115 ** B has itself registered for an unlock-notify callback when connection
7116 ** A's transaction is concluded. ^Indirect deadlock is also detected, so
7117 ** the system is also considered to be deadlocked if connection B has
7118 ** registered for an unlock-notify callback on the conclusion of connection
7119 ** C's transaction, where connection C is waiting on connection A. ^Any
7120 ** number of levels of indirection are allowed.
7122 ** <b>The "DROP TABLE" Exception</b>
7124 ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost
7125 ** always appropriate to call sqlite3_unlock_notify(). There is however,
7126 ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
7127 ** SQLite checks if there are any currently executing SELECT statements
7128 ** that belong to the same connection. If there are, SQLITE_LOCKED is
7129 ** returned. In this case there is no "blocking connection", so invoking
7130 ** sqlite3_unlock_notify() results in the unlock-notify callback being
7131 ** invoked immediately. If the application then re-attempts the "DROP TABLE"
7132 ** or "DROP INDEX" query, an infinite loop might be the result.
7134 ** One way around this problem is to check the extended error code returned
7135 ** by an sqlite3_step() call. ^(If there is a blocking connection, then the
7136 ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
7137 ** the special "DROP TABLE/INDEX" case, the extended error code is just
7140 SQLITE_API int sqlite3_unlock_notify(
7141 sqlite3 *pBlocked, /* Waiting connection */
7142 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */
7143 void *pNotifyArg /* Argument to pass to xNotify */
7148 ** CAPI3REF: String Comparison
7150 ** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications
7151 ** and extensions to compare the contents of two buffers containing UTF-8
7152 ** strings in a case-independent fashion, using the same definition of "case
7153 ** independence" that SQLite uses internally when comparing identifiers.
7155 SQLITE_API int sqlite3_stricmp(const char *, const char *);
7156 SQLITE_API int sqlite3_strnicmp(const char *, const char *, int);
7159 ** CAPI3REF: String Globbing
7161 ** ^The [sqlite3_strglob(P,X)] interface returns zero if string X matches
7162 ** the glob pattern P, and it returns non-zero if string X does not match
7163 ** the glob pattern P. ^The definition of glob pattern matching used in
7164 ** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the
7165 ** SQL dialect used by SQLite. ^The sqlite3_strglob(P,X) function is case
7168 ** Note that this routine returns zero on a match and non-zero if the strings
7169 ** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
7171 SQLITE_API int sqlite3_strglob(const char *zGlob, const char *zStr);
7174 ** CAPI3REF: Error Logging Interface
7176 ** ^The [sqlite3_log()] interface writes a message into the [error log]
7177 ** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
7178 ** ^If logging is enabled, the zFormat string and subsequent arguments are
7179 ** used with [sqlite3_snprintf()] to generate the final output string.
7181 ** The sqlite3_log() interface is intended for use by extensions such as
7182 ** virtual tables, collating functions, and SQL functions. While there is
7183 ** nothing to prevent an application from calling sqlite3_log(), doing so
7184 ** is considered bad form.
7186 ** The zFormat string must not be NULL.
7188 ** To avoid deadlocks and other threading problems, the sqlite3_log() routine
7189 ** will not use dynamically allocated memory. The log message is stored in
7190 ** a fixed-length buffer on the stack. If the log message is longer than
7191 ** a few hundred characters, it will be truncated to the length of the
7194 SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...);
7197 ** CAPI3REF: Write-Ahead Log Commit Hook
7199 ** ^The [sqlite3_wal_hook()] function is used to register a callback that
7200 ** is invoked each time data is committed to a database in wal mode.
7202 ** ^(The callback is invoked by SQLite after the commit has taken place and
7203 ** the associated write-lock on the database released)^, so the implementation
7204 ** may read, write or [checkpoint] the database as required.
7206 ** ^The first parameter passed to the callback function when it is invoked
7207 ** is a copy of the third parameter passed to sqlite3_wal_hook() when
7208 ** registering the callback. ^The second is a copy of the database handle.
7209 ** ^The third parameter is the name of the database that was written to -
7210 ** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
7211 ** is the number of pages currently in the write-ahead log file,
7212 ** including those that were just committed.
7214 ** The callback function should normally return [SQLITE_OK]. ^If an error
7215 ** code is returned, that error will propagate back up through the
7216 ** SQLite code base to cause the statement that provoked the callback
7217 ** to report an error, though the commit will have still occurred. If the
7218 ** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
7219 ** that does not correspond to any valid SQLite error code, the results
7222 ** A single database handle may have at most a single write-ahead log callback
7223 ** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
7224 ** previously registered write-ahead log callback. ^Note that the
7225 ** [sqlite3_wal_autocheckpoint()] interface and the
7226 ** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
7227 ** those overwrite any prior [sqlite3_wal_hook()] settings.
7229 SQLITE_API void *sqlite3_wal_hook(
7231 int(*)(void *,sqlite3*,const char*,int),
7236 ** CAPI3REF: Configure an auto-checkpoint
7238 ** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
7239 ** [sqlite3_wal_hook()] that causes any database on [database connection] D
7240 ** to automatically [checkpoint]
7241 ** after committing a transaction if there are N or
7242 ** more frames in the [write-ahead log] file. ^Passing zero or
7243 ** a negative value as the nFrame parameter disables automatic
7244 ** checkpoints entirely.
7246 ** ^The callback registered by this function replaces any existing callback
7247 ** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback
7248 ** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
7249 ** configured by this function.
7251 ** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
7254 ** ^Checkpoints initiated by this mechanism are
7255 ** [sqlite3_wal_checkpoint_v2|PASSIVE].
7257 ** ^Every new [database connection] defaults to having the auto-checkpoint
7258 ** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
7259 ** pages. The use of this interface
7260 ** is only necessary if the default setting is found to be suboptimal
7261 ** for a particular application.
7263 SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
7266 ** CAPI3REF: Checkpoint a database
7268 ** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to
7269 ** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^
7271 ** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the
7272 ** [write-ahead log] for database X on [database connection] D to be
7273 ** transferred into the database file and for the write-ahead log to
7274 ** be reset. See the [checkpointing] documentation for addition
7277 ** This interface used to be the only way to cause a checkpoint to
7278 ** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()]
7279 ** interface was added. This interface is retained for backwards
7280 ** compatibility and as a convenience for applications that need to manually
7281 ** start a callback but which do not need the full power (and corresponding
7282 ** complication) of [sqlite3_wal_checkpoint_v2()].
7284 SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
7287 ** CAPI3REF: Checkpoint a database
7289 ** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint
7290 ** operation on database X of [database connection] D in mode M. Status
7291 ** information is written back into integers pointed to by L and C.)^
7292 ** ^(The M parameter must be a valid [checkpoint mode]:)^
7295 ** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
7296 ** ^Checkpoint as many frames as possible without waiting for any database
7297 ** readers or writers to finish, then sync the database file if all frames
7298 ** in the log were checkpointed. ^The [busy-handler callback]
7299 ** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode.
7300 ** ^On the other hand, passive mode might leave the checkpoint unfinished
7301 ** if there are concurrent readers or writers.
7303 ** <dt>SQLITE_CHECKPOINT_FULL<dd>
7304 ** ^This mode blocks (it invokes the
7305 ** [sqlite3_busy_handler|busy-handler callback]) until there is no
7306 ** database writer and all readers are reading from the most recent database
7307 ** snapshot. ^It then checkpoints all frames in the log file and syncs the
7308 ** database file. ^This mode blocks new database writers while it is pending,
7309 ** but new database readers are allowed to continue unimpeded.
7311 ** <dt>SQLITE_CHECKPOINT_RESTART<dd>
7312 ** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition
7313 ** that after checkpointing the log file it blocks (calls the
7314 ** [busy-handler callback])
7315 ** until all readers are reading from the database file only. ^This ensures
7316 ** that the next writer will restart the log file from the beginning.
7317 ** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new
7318 ** database writer attempts while it is pending, but does not impede readers.
7320 ** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd>
7321 ** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the
7322 ** addition that it also truncates the log file to zero bytes just prior
7323 ** to a successful return.
7326 ** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in
7327 ** the log file or to -1 if the checkpoint could not run because
7328 ** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not
7329 ** NULL,then *pnCkpt is set to the total number of checkpointed frames in the
7330 ** log file (including any that were already checkpointed before the function
7331 ** was called) or to -1 if the checkpoint could not run due to an error or
7332 ** because the database is not in WAL mode. ^Note that upon successful
7333 ** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been
7334 ** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero.
7336 ** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If
7337 ** any other process is running a checkpoint operation at the same time, the
7338 ** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a
7339 ** busy-handler configured, it will not be invoked in this case.
7341 ** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the
7342 ** exclusive "writer" lock on the database file. ^If the writer lock cannot be
7343 ** obtained immediately, and a busy-handler is configured, it is invoked and
7344 ** the writer lock retried until either the busy-handler returns 0 or the lock
7345 ** is successfully obtained. ^The busy-handler is also invoked while waiting for
7346 ** database readers as described above. ^If the busy-handler returns 0 before
7347 ** the writer lock is obtained or while waiting for database readers, the
7348 ** checkpoint operation proceeds from that point in the same way as
7349 ** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible
7350 ** without blocking any further. ^SQLITE_BUSY is returned in this case.
7352 ** ^If parameter zDb is NULL or points to a zero length string, then the
7353 ** specified operation is attempted on all WAL databases [attached] to
7354 ** [database connection] db. In this case the
7355 ** values written to output parameters *pnLog and *pnCkpt are undefined. ^If
7356 ** an SQLITE_BUSY error is encountered when processing one or more of the
7357 ** attached WAL databases, the operation is still attempted on any remaining
7358 ** attached databases and SQLITE_BUSY is returned at the end. ^If any other
7359 ** error occurs while processing an attached database, processing is abandoned
7360 ** and the error code is returned to the caller immediately. ^If no error
7361 ** (SQLITE_BUSY or otherwise) is encountered while processing the attached
7362 ** databases, SQLITE_OK is returned.
7364 ** ^If database zDb is the name of an attached database that is not in WAL
7365 ** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If
7366 ** zDb is not NULL (or a zero length string) and is not the name of any
7367 ** attached database, SQLITE_ERROR is returned to the caller.
7369 ** ^Unless it returns SQLITE_MISUSE,
7370 ** the sqlite3_wal_checkpoint_v2() interface
7371 ** sets the error information that is queried by
7372 ** [sqlite3_errcode()] and [sqlite3_errmsg()].
7374 ** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface
7377 SQLITE_API int sqlite3_wal_checkpoint_v2(
7378 sqlite3 *db, /* Database handle */
7379 const char *zDb, /* Name of attached database (or NULL) */
7380 int eMode, /* SQLITE_CHECKPOINT_* value */
7381 int *pnLog, /* OUT: Size of WAL log in frames */
7382 int *pnCkpt /* OUT: Total number of frames checkpointed */
7386 ** CAPI3REF: Checkpoint Mode Values
7387 ** KEYWORDS: {checkpoint mode}
7389 ** These constants define all valid values for the "checkpoint mode" passed
7390 ** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface.
7391 ** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the
7392 ** meaning of each of these checkpoint modes.
7394 #define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */
7395 #define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */
7396 #define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */
7397 #define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */
7400 ** CAPI3REF: Virtual Table Interface Configuration
7402 ** This function may be called by either the [xConnect] or [xCreate] method
7403 ** of a [virtual table] implementation to configure
7404 ** various facets of the virtual table interface.
7406 ** If this interface is invoked outside the context of an xConnect or
7407 ** xCreate virtual table method then the behavior is undefined.
7409 ** At present, there is only one option that may be configured using
7410 ** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options
7411 ** may be added in the future.
7413 SQLITE_API int sqlite3_vtab_config(sqlite3*, int op, ...);
7416 ** CAPI3REF: Virtual Table Configuration Options
7418 ** These macros define the various options to the
7419 ** [sqlite3_vtab_config()] interface that [virtual table] implementations
7420 ** can use to customize and optimize their behavior.
7423 ** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT
7424 ** <dd>Calls of the form
7425 ** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
7426 ** where X is an integer. If X is zero, then the [virtual table] whose
7427 ** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not
7428 ** support constraints. In this configuration (which is the default) if
7429 ** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire
7430 ** statement is rolled back as if [ON CONFLICT | OR ABORT] had been
7431 ** specified as part of the users SQL statement, regardless of the actual
7432 ** ON CONFLICT mode specified.
7434 ** If X is non-zero, then the virtual table implementation guarantees
7435 ** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before
7436 ** any modifications to internal or persistent data structures have been made.
7437 ** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite
7438 ** is able to roll back a statement or database transaction, and abandon
7439 ** or continue processing the current SQL statement as appropriate.
7440 ** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns
7441 ** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode
7444 ** Virtual table implementations that are required to handle OR REPLACE
7445 ** must do so within the [xUpdate] method. If a call to the
7446 ** [sqlite3_vtab_on_conflict()] function indicates that the current ON
7447 ** CONFLICT policy is REPLACE, the virtual table implementation should
7448 ** silently replace the appropriate rows within the xUpdate callback and
7449 ** return SQLITE_OK. Or, if this is not possible, it may return
7450 ** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT
7451 ** constraint handling.
7454 #define SQLITE_VTAB_CONSTRAINT_SUPPORT 1
7457 ** CAPI3REF: Determine The Virtual Table Conflict Policy
7459 ** This function may only be called from within a call to the [xUpdate] method
7460 ** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The
7461 ** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
7462 ** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
7463 ** of the SQL statement that triggered the call to the [xUpdate] method of the
7466 SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *);
7469 ** CAPI3REF: Conflict resolution modes
7470 ** KEYWORDS: {conflict resolution mode}
7472 ** These constants are returned by [sqlite3_vtab_on_conflict()] to
7473 ** inform a [virtual table] implementation what the [ON CONFLICT] mode
7474 ** is for the SQL statement being evaluated.
7476 ** Note that the [SQLITE_IGNORE] constant is also used as a potential
7477 ** return value from the [sqlite3_set_authorizer()] callback and that
7478 ** [SQLITE_ABORT] is also a [result code].
7480 #define SQLITE_ROLLBACK 1
7481 /* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
7482 #define SQLITE_FAIL 3
7483 /* #define SQLITE_ABORT 4 // Also an error code */
7484 #define SQLITE_REPLACE 5
7487 ** CAPI3REF: Prepared Statement Scan Status Opcodes
7488 ** KEYWORDS: {scanstatus options}
7490 ** The following constants can be used for the T parameter to the
7491 ** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a
7492 ** different metric for sqlite3_stmt_scanstatus() to return.
7494 ** When the value returned to V is a string, space to hold that string is
7495 ** managed by the prepared statement S and will be automatically freed when
7499 ** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt>
7500 ** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be
7501 ** set to the total number of times that the X-th loop has run.</dd>
7503 ** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt>
7504 ** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set
7505 ** to the total number of rows examined by all iterations of the X-th loop.</dd>
7507 ** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt>
7508 ** <dd>^The "double" variable pointed to by the T parameter will be set to the
7509 ** query planner's estimate for the average number of rows output from each
7510 ** iteration of the X-th loop. If the query planner's estimates was accurate,
7511 ** then this value will approximate the quotient NVISIT/NLOOP and the
7512 ** product of this value for all prior loops with the same SELECTID will
7513 ** be the NLOOP value for the current loop.
7515 ** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt>
7516 ** <dd>^The "const char *" variable pointed to by the T parameter will be set
7517 ** to a zero-terminated UTF-8 string containing the name of the index or table
7518 ** used for the X-th loop.
7520 ** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt>
7521 ** <dd>^The "const char *" variable pointed to by the T parameter will be set
7522 ** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN]
7523 ** description for the X-th loop.
7525 ** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt>
7526 ** <dd>^The "int" variable pointed to by the T parameter will be set to the
7527 ** "select-id" for the X-th loop. The select-id identifies which query or
7528 ** subquery the loop is part of. The main query has a select-id of zero.
7529 ** The select-id is the same value as is output in the first column
7530 ** of an [EXPLAIN QUERY PLAN] query.
7533 #define SQLITE_SCANSTAT_NLOOP 0
7534 #define SQLITE_SCANSTAT_NVISIT 1
7535 #define SQLITE_SCANSTAT_EST 2
7536 #define SQLITE_SCANSTAT_NAME 3
7537 #define SQLITE_SCANSTAT_EXPLAIN 4
7538 #define SQLITE_SCANSTAT_SELECTID 5
7541 ** CAPI3REF: Prepared Statement Scan Status
7543 ** This interface returns information about the predicted and measured
7544 ** performance for pStmt. Advanced applications can use this
7545 ** interface to compare the predicted and the measured performance and
7546 ** issue warnings and/or rerun [ANALYZE] if discrepancies are found.
7548 ** Since this interface is expected to be rarely used, it is only
7549 ** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS]
7550 ** compile-time option.
7552 ** The "iScanStatusOp" parameter determines which status information to return.
7553 ** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior
7554 ** of this interface is undefined.
7555 ** ^The requested measurement is written into a variable pointed to by
7556 ** the "pOut" parameter.
7557 ** Parameter "idx" identifies the specific loop to retrieve statistics for.
7558 ** Loops are numbered starting from zero. ^If idx is out of range - less than
7559 ** zero or greater than or equal to the total number of loops used to implement
7560 ** the statement - a non-zero value is returned and the variable that pOut
7561 ** points to is unchanged.
7563 ** ^Statistics might not be available for all loops in all statements. ^In cases
7564 ** where there exist loops with no available statistics, this function behaves
7565 ** as if the loop did not exist - it returns non-zero and leave the variable
7566 ** that pOut points to unchanged.
7568 ** See also: [sqlite3_stmt_scanstatus_reset()]
7570 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_stmt_scanstatus(
7571 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */
7572 int idx, /* Index of loop to report on */
7573 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */
7574 void *pOut /* Result written here */
7578 ** CAPI3REF: Zero Scan-Status Counters
7580 ** ^Zero all [sqlite3_stmt_scanstatus()] related event counters.
7582 ** This API is only available if the library is built with pre-processor
7583 ** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined.
7585 SQLITE_API SQLITE_EXPERIMENTAL void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*);
7589 ** Undo the hack that converts floating point types to integer for
7590 ** builds on processors without floating point support.
7592 #ifdef SQLITE_OMIT_FLOATING_POINT
7597 } /* End of the 'extern "C"' block */
7599 #endif /* _SQLITE3_H_ */
7604 ** The author disclaims copyright to this source code. In place of
7605 ** a legal notice, here is a blessing:
7607 ** May you do good and not evil.
7608 ** May you find forgiveness for yourself and forgive others.
7609 ** May you share freely, never taking more than you give.
7611 *************************************************************************
7614 #ifndef _SQLITE3RTREE_H_
7615 #define _SQLITE3RTREE_H_
7622 typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry;
7623 typedef struct sqlite3_rtree_query_info sqlite3_rtree_query_info;
7625 /* The double-precision datatype used by RTree depends on the
7626 ** SQLITE_RTREE_INT_ONLY compile-time option.
7628 #ifdef SQLITE_RTREE_INT_ONLY
7629 typedef sqlite3_int64 sqlite3_rtree_dbl;
7631 typedef double sqlite3_rtree_dbl;
7635 ** Register a geometry callback named zGeom that can be used as part of an
7636 ** R-Tree geometry query as follows:
7638 ** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...)
7640 SQLITE_API int sqlite3_rtree_geometry_callback(
7643 int (*xGeom)(sqlite3_rtree_geometry*, int, sqlite3_rtree_dbl*,int*),
7649 ** A pointer to a structure of the following type is passed as the first
7650 ** argument to callbacks registered using rtree_geometry_callback().
7652 struct sqlite3_rtree_geometry {
7653 void *pContext; /* Copy of pContext passed to s_r_g_c() */
7654 int nParam; /* Size of array aParam[] */
7655 sqlite3_rtree_dbl *aParam; /* Parameters passed to SQL geom function */
7656 void *pUser; /* Callback implementation user data */
7657 void (*xDelUser)(void *); /* Called by SQLite to clean up pUser */
7661 ** Register a 2nd-generation geometry callback named zScore that can be
7662 ** used as part of an R-Tree geometry query as follows:
7664 ** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zQueryFunc(... params ...)
7666 SQLITE_API int sqlite3_rtree_query_callback(
7668 const char *zQueryFunc,
7669 int (*xQueryFunc)(sqlite3_rtree_query_info*),
7671 void (*xDestructor)(void*)
7676 ** A pointer to a structure of the following type is passed as the
7677 ** argument to scored geometry callback registered using
7678 ** sqlite3_rtree_query_callback().
7680 ** Note that the first 5 fields of this structure are identical to
7681 ** sqlite3_rtree_geometry. This structure is a subclass of
7682 ** sqlite3_rtree_geometry.
7684 struct sqlite3_rtree_query_info {
7685 void *pContext; /* pContext from when function registered */
7686 int nParam; /* Number of function parameters */
7687 sqlite3_rtree_dbl *aParam; /* value of function parameters */
7688 void *pUser; /* callback can use this, if desired */
7689 void (*xDelUser)(void*); /* function to free pUser */
7690 sqlite3_rtree_dbl *aCoord; /* Coordinates of node or entry to check */
7691 unsigned int *anQueue; /* Number of pending entries in the queue */
7692 int nCoord; /* Number of coordinates */
7693 int iLevel; /* Level of current node or entry */
7694 int mxLevel; /* The largest iLevel value in the tree */
7695 sqlite3_int64 iRowid; /* Rowid for current entry */
7696 sqlite3_rtree_dbl rParentScore; /* Score of parent node */
7697 int eParentWithin; /* Visibility of parent node */
7698 int eWithin; /* OUT: Visiblity */
7699 sqlite3_rtree_dbl rScore; /* OUT: Write the score here */
7703 ** Allowed values for sqlite3_rtree_query.eWithin and .eParentWithin.
7705 #define NOT_WITHIN 0 /* Object completely outside of query region */
7706 #define PARTLY_WITHIN 1 /* Object partially overlaps query region */
7707 #define FULLY_WITHIN 2 /* Object fully contained within query region */
7710 SQLITE_API void sqlite3_set_dbdir (sqlite3* db, const char* dir);
7713 } /* end of the 'extern "C"' block */
7716 #endif /* ifndef _SQLITE3RTREE_H_ */