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 support 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 {H10010} <S60100>
86
** The SQLITE_VERSION and SQLITE_VERSION_NUMBER #defines in
87
** the sqlite3.h file specify the version of SQLite with which
88
** that header file is associated.
90
** The "version" of SQLite is a string of the form "W.X.Y" or "W.X.Y.Z".
91
** The W value is major version number and is always 3 in SQLite3.
92
** The W value only changes when backwards compatibility is
93
** broken and we intend to never break backwards compatibility.
94
** The X value is the minor version number and only changes when
95
** there are major feature enhancements that are forwards compatible
96
** but not backwards compatible.
97
** The Y value is the release number and is incremented with
98
** each release but resets back to 0 whenever X is incremented.
99
** The Z value only appears on branch releases.
101
** The SQLITE_VERSION_NUMBER is an integer that is computed as
105
** SQLITE_VERSION_NUMBER = W*1000000 + X*1000 + Y
106
** </pre></blockquote>
108
** Since version 3.6.18, SQLite source code has been stored in the
109
** <a href="http://www.fossil-scm.org/">fossil configuration management
110
** system</a>. The SQLITE_SOURCE_ID
111
** macro is a string which identifies a particular check-in of SQLite
112
** within its configuration management system. The string contains the
113
** date and time of the check-in (UTC) and an SHA1 hash of the entire
116
** See also: [sqlite3_libversion()],
117
** [sqlite3_libversion_number()], [sqlite3_sourceid()],
118
** [sqlite_version()] and [sqlite_source_id()].
120
** Requirements: [H10011] [H10014]
122
#define SQLITE_VERSION "3.6.20"
123
#define SQLITE_VERSION_NUMBER 3006020
124
#define SQLITE_SOURCE_ID "2009-11-04 13:30:02 eb7a544fe49d1626bacecfe53ddc03fe082e3243"
127
** CAPI3REF: Run-Time Library Version Numbers {H10020} <S60100>
128
** KEYWORDS: sqlite3_version
130
** These interfaces provide the same information as the [SQLITE_VERSION],
131
** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] #defines in the header,
132
** but are associated with the library instead of the header file. Cautious
133
** programmers might include assert() statements in their application to
134
** verify that values returned by these interfaces match the macros in
135
** the header, and thus insure that the application is
136
** compiled with matching library and header files.
139
** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
140
** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 );
141
** assert( strcmp(sqlite3_libversion,SQLITE_VERSION)==0 );
142
** </pre></blockquote>
144
** The sqlite3_libversion() function returns the same information as is
145
** in the sqlite3_version[] string constant. The function is provided
146
** for use in DLLs since DLL users usually do not have direct access to string
147
** constants within the DLL. Similarly, the sqlite3_sourceid() function
148
** returns the same information as is in the [SQLITE_SOURCE_ID] #define of
151
** See also: [sqlite_version()] and [sqlite_source_id()].
153
** Requirements: [H10021] [H10022] [H10023]
155
SQLITE_API SQLITE_EXTERN const char sqlite3_version[];
156
SQLITE_API const char *sqlite3_libversion(void);
157
SQLITE_API const char *sqlite3_sourceid(void);
158
SQLITE_API int sqlite3_libversion_number(void);
161
** CAPI3REF: Test To See If The Library Is Threadsafe {H10100} <S60100>
163
** SQLite can be compiled with or without mutexes. When
164
** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
165
** are enabled and SQLite is threadsafe. When the
166
** [SQLITE_THREADSAFE] macro is 0,
167
** the mutexes are omitted. Without the mutexes, it is not safe
168
** to use SQLite concurrently from more than one thread.
170
** Enabling mutexes incurs a measurable performance penalty.
171
** So if speed is of utmost importance, it makes sense to disable
172
** the mutexes. But for maximum safety, mutexes should be enabled.
173
** The default behavior is for mutexes to be enabled.
175
** This interface can be used by an application to make sure that the
176
** version of SQLite that it is linking against was compiled with
177
** the desired setting of the [SQLITE_THREADSAFE] macro.
179
** This interface only reports on the compile-time mutex setting
180
** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with
181
** SQLITE_THREADSAFE=1 then mutexes are enabled by default but
182
** can be fully or partially disabled using a call to [sqlite3_config()]
183
** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD],
184
** or [SQLITE_CONFIG_MUTEX]. The return value of this function shows
185
** only the default compile-time setting, not any run-time changes
188
** See the [threading mode] documentation for additional information.
190
** Requirements: [H10101] [H10102]
192
SQLITE_API int sqlite3_threadsafe(void);
195
** CAPI3REF: Database Connection Handle {H12000} <S40200>
196
** KEYWORDS: {database connection} {database connections}
198
** Each open SQLite database is represented by a pointer to an instance of
199
** the opaque structure named "sqlite3". It is useful to think of an sqlite3
200
** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and
201
** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
202
** is its destructor. There are many other interfaces (such as
203
** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
204
** [sqlite3_busy_timeout()] to name but three) that are methods on an
207
typedef struct sqlite3 sqlite3;
210
** CAPI3REF: 64-Bit Integer Types {H10200} <S10110>
211
** KEYWORDS: sqlite_int64 sqlite_uint64
213
** Because there is no cross-platform way to specify 64-bit integer types
214
** SQLite includes typedefs for 64-bit signed and unsigned integers.
216
** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
217
** The sqlite_int64 and sqlite_uint64 types are supported for backwards
218
** compatibility only.
220
** Requirements: [H10201] [H10202]
222
#ifdef SQLITE_INT64_TYPE
223
typedef SQLITE_INT64_TYPE sqlite_int64;
224
typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
225
#elif defined(_MSC_VER) || defined(__BORLANDC__)
226
typedef __int64 sqlite_int64;
227
typedef unsigned __int64 sqlite_uint64;
229
typedef long long int sqlite_int64;
230
typedef unsigned long long int sqlite_uint64;
232
typedef sqlite_int64 sqlite3_int64;
233
typedef sqlite_uint64 sqlite3_uint64;
236
** If compiling for a processor that lacks floating point support,
237
** substitute integer for floating-point.
239
#ifdef SQLITE_OMIT_FLOATING_POINT
240
# define double sqlite3_int64
244
** CAPI3REF: Closing A Database Connection {H12010} <S30100><S40200>
246
** This routine is the destructor for the [sqlite3] object.
248
** Applications must [sqlite3_finalize | finalize] all [prepared statements]
249
** and [sqlite3_blob_close | close] all [BLOB handles] associated with
250
** the [sqlite3] object prior to attempting to close the object.
252
** If [sqlite3_close()] is invoked while a transaction is open,
253
** the transaction is automatically rolled back.
255
** The C parameter to [sqlite3_close(C)] must be either a NULL
256
** pointer or an [sqlite3] object pointer obtained
257
** from [sqlite3_open()], [sqlite3_open16()], or
258
** [sqlite3_open_v2()], and not previously closed.
261
** [H12011] [H12012] [H12013] [H12014] [H12015] [H12019]
263
SQLITE_API int sqlite3_close(sqlite3 *);
266
** The type for a callback function.
267
** This is legacy and deprecated. It is included for historical
268
** compatibility and is not documented.
270
typedef int (*sqlite3_callback)(void*,int,char**, char**);
273
** CAPI3REF: One-Step Query Execution Interface {H12100} <S10000>
275
** The sqlite3_exec() interface is a convenient way of running one or more
276
** SQL statements without having to write a lot of C code. The UTF-8 encoded
277
** SQL statements are passed in as the second parameter to sqlite3_exec().
278
** The statements are evaluated one by one until either an error or
279
** an interrupt is encountered, or until they are all done. The 3rd parameter
280
** is an optional callback that is invoked once for each row of any query
281
** results produced by the SQL statements. The 5th parameter tells where
282
** to write any error messages.
284
** The error message passed back through the 5th parameter is held
285
** in memory obtained from [sqlite3_malloc()]. To avoid a memory leak,
286
** the calling application should call [sqlite3_free()] on any error
287
** message returned through the 5th parameter when it has finished using
288
** the error message.
290
** If the SQL statement in the 2nd parameter is NULL or an empty string
291
** or a string containing only whitespace and comments, then no SQL
292
** statements are evaluated and the database is not changed.
294
** The sqlite3_exec() interface is implemented in terms of
295
** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()].
296
** The sqlite3_exec() routine does nothing to the database that cannot be done
297
** by [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()].
299
** The first parameter to [sqlite3_exec()] must be an valid and open
300
** [database connection].
302
** The database connection must not be closed while
303
** [sqlite3_exec()] is running.
305
** The calling function should use [sqlite3_free()] to free
306
** the memory that *errmsg is left pointing at once the error
307
** message is no longer needed.
309
** The SQL statement text in the 2nd parameter to [sqlite3_exec()]
310
** must remain unchanged while [sqlite3_exec()] is running.
313
** [H12101] [H12102] [H12104] [H12105] [H12107] [H12110] [H12113] [H12116]
314
** [H12119] [H12122] [H12125] [H12131] [H12134] [H12137] [H12138]
316
SQLITE_API int sqlite3_exec(
317
sqlite3*, /* An open database */
318
const char *sql, /* SQL to be evaluated */
319
int (*callback)(void*,int,char**,char**), /* Callback function */
320
void *, /* 1st argument to callback */
321
char **errmsg /* Error msg written here */
325
** CAPI3REF: Result Codes {H10210} <S10700>
326
** KEYWORDS: SQLITE_OK {error code} {error codes}
327
** KEYWORDS: {result code} {result codes}
329
** Many SQLite functions return an integer result code from the set shown
330
** here in order to indicates success or failure.
332
** New error codes may be added in future versions of SQLite.
334
** See also: [SQLITE_IOERR_READ | extended result codes]
336
#define SQLITE_OK 0 /* Successful result */
337
/* beginning-of-error-codes */
338
#define SQLITE_ERROR 1 /* SQL error or missing database */
339
#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */
340
#define SQLITE_PERM 3 /* Access permission denied */
341
#define SQLITE_ABORT 4 /* Callback routine requested an abort */
342
#define SQLITE_BUSY 5 /* The database file is locked */
343
#define SQLITE_LOCKED 6 /* A table in the database is locked */
344
#define SQLITE_NOMEM 7 /* A malloc() failed */
345
#define SQLITE_READONLY 8 /* Attempt to write a readonly database */
346
#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/
347
#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */
348
#define SQLITE_CORRUPT 11 /* The database disk image is malformed */
349
#define SQLITE_NOTFOUND 12 /* NOT USED. Table or record not found */
350
#define SQLITE_FULL 13 /* Insertion failed because database is full */
351
#define SQLITE_CANTOPEN 14 /* Unable to open the database file */
352
#define SQLITE_PROTOCOL 15 /* NOT USED. Database lock protocol error */
353
#define SQLITE_EMPTY 16 /* Database is empty */
354
#define SQLITE_SCHEMA 17 /* The database schema changed */
355
#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */
356
#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */
357
#define SQLITE_MISMATCH 20 /* Data type mismatch */
358
#define SQLITE_MISUSE 21 /* Library used incorrectly */
359
#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */
360
#define SQLITE_AUTH 23 /* Authorization denied */
361
#define SQLITE_FORMAT 24 /* Auxiliary database format error */
362
#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */
363
#define SQLITE_NOTADB 26 /* File opened that is not a database file */
364
#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */
365
#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */
366
/* end-of-error-codes */
369
** CAPI3REF: Extended Result Codes {H10220} <S10700>
370
** KEYWORDS: {extended error code} {extended error codes}
371
** KEYWORDS: {extended result code} {extended result codes}
373
** In its default configuration, SQLite API routines return one of 26 integer
374
** [SQLITE_OK | result codes]. However, experience has shown that many of
375
** these result codes are too coarse-grained. They do not provide as
376
** much information about problems as programmers might like. In an effort to
377
** address this, newer versions of SQLite (version 3.3.8 and later) include
378
** support for additional result codes that provide more detailed information
379
** about errors. The extended result codes are enabled or disabled
380
** on a per database connection basis using the
381
** [sqlite3_extended_result_codes()] API.
383
** Some of the available extended result codes are listed here.
384
** One may expect the number of extended result codes will be expand
385
** over time. Software that uses extended result codes should expect
386
** to see new result codes in future releases of SQLite.
388
** The SQLITE_OK result code will never be extended. It will always
391
#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8))
392
#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8))
393
#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8))
394
#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8))
395
#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8))
396
#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8))
397
#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8))
398
#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8))
399
#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8))
400
#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8))
401
#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8))
402
#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8))
403
#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8))
404
#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
405
#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8))
406
#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8))
407
#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8))
408
#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8) )
411
** CAPI3REF: Flags For File Open Operations {H10230} <H11120> <H12700>
413
** These bit values are intended for use in the
414
** 3rd parameter to the [sqlite3_open_v2()] interface and
415
** in the 4th parameter to the xOpen method of the
416
** [sqlite3_vfs] object.
418
#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */
419
#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */
420
#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */
421
#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */
422
#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */
423
#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */
424
#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */
425
#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */
426
#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */
427
#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */
428
#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */
429
#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */
430
#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */
431
#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */
432
#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */
433
#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */
436
** CAPI3REF: Device Characteristics {H10240} <H11120>
438
** The xDeviceCapabilities method of the [sqlite3_io_methods]
439
** object returns an integer which is a vector of the these
440
** bit values expressing I/O characteristics of the mass storage
441
** device that holds the file that the [sqlite3_io_methods]
444
** The SQLITE_IOCAP_ATOMIC property means that all writes of
445
** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
446
** mean that writes of blocks that are nnn bytes in size and
447
** are aligned to an address which is an integer multiple of
448
** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
449
** that when data is appended to a file, the data is appended
450
** first then the size of the file is extended, never the other
451
** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
452
** information is written to disk in the same order as calls
455
#define SQLITE_IOCAP_ATOMIC 0x00000001
456
#define SQLITE_IOCAP_ATOMIC512 0x00000002
457
#define SQLITE_IOCAP_ATOMIC1K 0x00000004
458
#define SQLITE_IOCAP_ATOMIC2K 0x00000008
459
#define SQLITE_IOCAP_ATOMIC4K 0x00000010
460
#define SQLITE_IOCAP_ATOMIC8K 0x00000020
461
#define SQLITE_IOCAP_ATOMIC16K 0x00000040
462
#define SQLITE_IOCAP_ATOMIC32K 0x00000080
463
#define SQLITE_IOCAP_ATOMIC64K 0x00000100
464
#define SQLITE_IOCAP_SAFE_APPEND 0x00000200
465
#define SQLITE_IOCAP_SEQUENTIAL 0x00000400
468
** CAPI3REF: File Locking Levels {H10250} <H11120> <H11310>
470
** SQLite uses one of these integer values as the second
471
** argument to calls it makes to the xLock() and xUnlock() methods
472
** of an [sqlite3_io_methods] object.
474
#define SQLITE_LOCK_NONE 0
475
#define SQLITE_LOCK_SHARED 1
476
#define SQLITE_LOCK_RESERVED 2
477
#define SQLITE_LOCK_PENDING 3
478
#define SQLITE_LOCK_EXCLUSIVE 4
481
** CAPI3REF: Synchronization Type Flags {H10260} <H11120>
483
** When SQLite invokes the xSync() method of an
484
** [sqlite3_io_methods] object it uses a combination of
485
** these integer values as the second argument.
487
** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
488
** sync operation only needs to flush data to mass storage. Inode
489
** information need not be flushed. If the lower four bits of the flag
490
** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
491
** If the lower four bits equal SQLITE_SYNC_FULL, that means
492
** to use Mac OS X style fullsync instead of fsync().
494
#define SQLITE_SYNC_NORMAL 0x00002
495
#define SQLITE_SYNC_FULL 0x00003
496
#define SQLITE_SYNC_DATAONLY 0x00010
499
** CAPI3REF: OS Interface Open File Handle {H11110} <S20110>
501
** An [sqlite3_file] object represents an open file in the
502
** [sqlite3_vfs | OS interface layer]. Individual OS interface
503
** implementations will
504
** want to subclass this object by appending additional fields
505
** for their own use. The pMethods entry is a pointer to an
506
** [sqlite3_io_methods] object that defines methods for performing
507
** I/O operations on the open file.
509
typedef struct sqlite3_file sqlite3_file;
510
struct sqlite3_file {
511
const struct sqlite3_io_methods *pMethods; /* Methods for an open file */
515
** CAPI3REF: OS Interface File Virtual Methods Object {H11120} <S20110>
517
** Every file opened by the [sqlite3_vfs] xOpen method populates an
518
** [sqlite3_file] object (or, more commonly, a subclass of the
519
** [sqlite3_file] object) with a pointer to an instance of this object.
520
** This object defines the methods used to perform various operations
521
** against the open file represented by the [sqlite3_file] object.
523
** If the xOpen method sets the sqlite3_file.pMethods element
524
** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
525
** may be invoked even if the xOpen reported that it failed. The
526
** only way to prevent a call to xClose following a failed xOpen
527
** is for the xOpen to set the sqlite3_file.pMethods element to NULL.
529
** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
530
** [SQLITE_SYNC_FULL]. The first choice is the normal fsync().
531
** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY]
532
** flag may be ORed in to indicate that only the data of the file
533
** and not its inode needs to be synced.
535
** The integer values to xLock() and xUnlock() are one of
537
** <li> [SQLITE_LOCK_NONE],
538
** <li> [SQLITE_LOCK_SHARED],
539
** <li> [SQLITE_LOCK_RESERVED],
540
** <li> [SQLITE_LOCK_PENDING], or
541
** <li> [SQLITE_LOCK_EXCLUSIVE].
543
** xLock() increases the lock. xUnlock() decreases the lock.
544
** The xCheckReservedLock() method checks whether any database connection,
545
** either in this process or in some other process, is holding a RESERVED,
546
** PENDING, or EXCLUSIVE lock on the file. It returns true
547
** if such a lock exists and false otherwise.
549
** The xFileControl() method is a generic interface that allows custom
550
** VFS implementations to directly control an open file using the
551
** [sqlite3_file_control()] interface. The second "op" argument is an
552
** integer opcode. The third argument is a generic pointer intended to
553
** point to a structure that may contain arguments or space in which to
554
** write return values. Potential uses for xFileControl() might be
555
** functions to enable blocking locks with timeouts, to change the
556
** locking strategy (for example to use dot-file locks), to inquire
557
** about the status of a lock, or to break stale locks. The SQLite
558
** core reserves all opcodes less than 100 for its own use.
559
** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available.
560
** Applications that define a custom xFileControl method should use opcodes
561
** greater than 100 to avoid conflicts.
563
** The xSectorSize() method returns the sector size of the
564
** device that underlies the file. The sector size is the
565
** minimum write that can be performed without disturbing
566
** other bytes in the file. The xDeviceCharacteristics()
567
** method returns a bit vector describing behaviors of the
568
** underlying device:
571
** <li> [SQLITE_IOCAP_ATOMIC]
572
** <li> [SQLITE_IOCAP_ATOMIC512]
573
** <li> [SQLITE_IOCAP_ATOMIC1K]
574
** <li> [SQLITE_IOCAP_ATOMIC2K]
575
** <li> [SQLITE_IOCAP_ATOMIC4K]
576
** <li> [SQLITE_IOCAP_ATOMIC8K]
577
** <li> [SQLITE_IOCAP_ATOMIC16K]
578
** <li> [SQLITE_IOCAP_ATOMIC32K]
579
** <li> [SQLITE_IOCAP_ATOMIC64K]
580
** <li> [SQLITE_IOCAP_SAFE_APPEND]
581
** <li> [SQLITE_IOCAP_SEQUENTIAL]
584
** The SQLITE_IOCAP_ATOMIC property means that all writes of
585
** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
586
** mean that writes of blocks that are nnn bytes in size and
587
** are aligned to an address which is an integer multiple of
588
** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
589
** that when data is appended to a file, the data is appended
590
** first then the size of the file is extended, never the other
591
** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
592
** information is written to disk in the same order as calls
595
** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
596
** in the unread portions of the buffer with zeros. A VFS that
597
** fails to zero-fill short reads might seem to work. However,
598
** failure to zero-fill short reads will eventually lead to
599
** database corruption.
601
typedef struct sqlite3_io_methods sqlite3_io_methods;
602
struct sqlite3_io_methods {
604
int (*xClose)(sqlite3_file*);
605
int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
606
int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
607
int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
608
int (*xSync)(sqlite3_file*, int flags);
609
int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
610
int (*xLock)(sqlite3_file*, int);
611
int (*xUnlock)(sqlite3_file*, int);
612
int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
613
int (*xFileControl)(sqlite3_file*, int op, void *pArg);
614
int (*xSectorSize)(sqlite3_file*);
615
int (*xDeviceCharacteristics)(sqlite3_file*);
616
/* Additional methods may be added in future releases */
620
** CAPI3REF: Standard File Control Opcodes {H11310} <S30800>
622
** These integer constants are opcodes for the xFileControl method
623
** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
626
** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This
627
** opcode causes the xFileControl method to write the current state of
628
** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
629
** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
630
** into an integer that the pArg argument points to. This capability
631
** is used during testing and only needs to be supported when SQLITE_TEST
634
#define SQLITE_FCNTL_LOCKSTATE 1
635
#define SQLITE_GET_LOCKPROXYFILE 2
636
#define SQLITE_SET_LOCKPROXYFILE 3
637
#define SQLITE_LAST_ERRNO 4
640
** CAPI3REF: Mutex Handle {H17110} <S20130>
642
** The mutex module within SQLite defines [sqlite3_mutex] to be an
643
** abstract type for a mutex object. The SQLite core never looks
644
** at the internal representation of an [sqlite3_mutex]. It only
645
** deals with pointers to the [sqlite3_mutex] object.
647
** Mutexes are created using [sqlite3_mutex_alloc()].
649
typedef struct sqlite3_mutex sqlite3_mutex;
652
** CAPI3REF: OS Interface Object {H11140} <S20100>
654
** An instance of the sqlite3_vfs object defines the interface between
655
** the SQLite core and the underlying operating system. The "vfs"
656
** in the name of the object stands for "virtual file system".
658
** The value of the iVersion field is initially 1 but may be larger in
659
** future versions of SQLite. Additional fields may be appended to this
660
** object when the iVersion value is increased. Note that the structure
661
** of the sqlite3_vfs object changes in the transaction between
662
** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not
665
** The szOsFile field is the size of the subclassed [sqlite3_file]
666
** structure used by this VFS. mxPathname is the maximum length of
667
** a pathname in this VFS.
669
** Registered sqlite3_vfs objects are kept on a linked list formed by
670
** the pNext pointer. The [sqlite3_vfs_register()]
671
** and [sqlite3_vfs_unregister()] interfaces manage this list
672
** in a thread-safe way. The [sqlite3_vfs_find()] interface
673
** searches the list. Neither the application code nor the VFS
674
** implementation should use the pNext pointer.
676
** The pNext field is the only field in the sqlite3_vfs
677
** structure that SQLite will ever modify. SQLite will only access
678
** or modify this field while holding a particular static mutex.
679
** The application should never modify anything within the sqlite3_vfs
680
** object once the object has been registered.
682
** The zName field holds the name of the VFS module. The name must
683
** be unique across all VFS modules.
685
** SQLite will guarantee that the zFilename parameter to xOpen
686
** is either a NULL pointer or string obtained
687
** from xFullPathname(). SQLite further guarantees that
688
** the string will be valid and unchanged until xClose() is
689
** called. Because of the previous sentence,
690
** the [sqlite3_file] can safely store a pointer to the
691
** filename if it needs to remember the filename for some reason.
692
** If the zFilename parameter is xOpen is a NULL pointer then xOpen
693
** must invent its own temporary name for the file. Whenever the
694
** xFilename parameter is NULL it will also be the case that the
695
** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
697
** The flags argument to xOpen() includes all bits set in
698
** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()]
699
** or [sqlite3_open16()] is used, then flags includes at least
700
** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE].
701
** If xOpen() opens a file read-only then it sets *pOutFlags to
702
** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set.
704
** SQLite will also add one of the following flags to the xOpen()
705
** call, depending on the object being opened:
708
** <li> [SQLITE_OPEN_MAIN_DB]
709
** <li> [SQLITE_OPEN_MAIN_JOURNAL]
710
** <li> [SQLITE_OPEN_TEMP_DB]
711
** <li> [SQLITE_OPEN_TEMP_JOURNAL]
712
** <li> [SQLITE_OPEN_TRANSIENT_DB]
713
** <li> [SQLITE_OPEN_SUBJOURNAL]
714
** <li> [SQLITE_OPEN_MASTER_JOURNAL]
717
** The file I/O implementation can use the object type flags to
718
** change the way it deals with files. For example, an application
719
** that does not care about crash recovery or rollback might make
720
** the open of a journal file a no-op. Writes to this journal would
721
** also be no-ops, and any attempt to read the journal would return
722
** SQLITE_IOERR. Or the implementation might recognize that a database
723
** file will be doing page-aligned sector reads and writes in a random
724
** order and set up its I/O subsystem accordingly.
726
** SQLite might also add one of the following flags to the xOpen method:
729
** <li> [SQLITE_OPEN_DELETEONCLOSE]
730
** <li> [SQLITE_OPEN_EXCLUSIVE]
733
** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
734
** deleted when it is closed. The [SQLITE_OPEN_DELETEONCLOSE]
735
** will be set for TEMP databases, journals and for subjournals.
737
** The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
738
** with the [SQLITE_OPEN_CREATE] flag, which are both directly
739
** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
740
** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
741
** SQLITE_OPEN_CREATE, is used to indicate that file should always
742
** be created, and that it is an error if it already exists.
743
** It is <i>not</i> used to indicate the file should be opened
744
** for exclusive access.
746
** At least szOsFile bytes of memory are allocated by SQLite
747
** to hold the [sqlite3_file] structure passed as the third
748
** argument to xOpen. The xOpen method does not have to
749
** allocate the structure; it should just fill it in. Note that
750
** the xOpen method must set the sqlite3_file.pMethods to either
751
** a valid [sqlite3_io_methods] object or to NULL. xOpen must do
752
** this even if the open fails. SQLite expects that the sqlite3_file.pMethods
753
** element will be valid after xOpen returns regardless of the success
754
** or failure of the xOpen call.
756
** The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
757
** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
758
** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
759
** to test whether a file is at least readable. The file can be a
762
** SQLite will always allocate at least mxPathname+1 bytes for the
763
** output buffer xFullPathname. The exact size of the output buffer
764
** is also passed as a parameter to both methods. If the output buffer
765
** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
766
** handled as a fatal error by SQLite, vfs implementations should endeavor
767
** to prevent this by setting mxPathname to a sufficiently large value.
769
** The xRandomness(), xSleep(), and xCurrentTime() interfaces
770
** are not strictly a part of the filesystem, but they are
771
** included in the VFS structure for completeness.
772
** The xRandomness() function attempts to return nBytes bytes
773
** of good-quality randomness into zOut. The return value is
774
** the actual number of bytes of randomness obtained.
775
** The xSleep() method causes the calling thread to sleep for at
776
** least the number of microseconds given. The xCurrentTime()
777
** method returns a Julian Day Number for the current date and time.
780
typedef struct sqlite3_vfs sqlite3_vfs;
782
int iVersion; /* Structure version number */
783
int szOsFile; /* Size of subclassed sqlite3_file */
784
int mxPathname; /* Maximum file pathname length */
785
sqlite3_vfs *pNext; /* Next registered VFS */
786
const char *zName; /* Name of this virtual file system */
787
void *pAppData; /* Pointer to application-specific data */
788
int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
789
int flags, int *pOutFlags);
790
int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
791
int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
792
int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
793
void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
794
void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
795
void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
796
void (*xDlClose)(sqlite3_vfs*, void*);
797
int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
798
int (*xSleep)(sqlite3_vfs*, int microseconds);
799
int (*xCurrentTime)(sqlite3_vfs*, double*);
800
int (*xGetLastError)(sqlite3_vfs*, int, char *);
801
/* New fields may be appended in figure versions. The iVersion
802
** value will increment whenever this happens. */
806
** CAPI3REF: Flags for the xAccess VFS method {H11190} <H11140>
808
** These integer constants can be used as the third parameter to
809
** the xAccess method of an [sqlite3_vfs] object. {END} They determine
810
** what kind of permissions the xAccess method is looking for.
811
** With SQLITE_ACCESS_EXISTS, the xAccess method
812
** simply checks whether the file exists.
813
** With SQLITE_ACCESS_READWRITE, the xAccess method
814
** checks whether the file is both readable and writable.
815
** With SQLITE_ACCESS_READ, the xAccess method
816
** checks whether the file is readable.
818
#define SQLITE_ACCESS_EXISTS 0
819
#define SQLITE_ACCESS_READWRITE 1
820
#define SQLITE_ACCESS_READ 2
823
** CAPI3REF: Initialize The SQLite Library {H10130} <S20000><S30100>
825
** The sqlite3_initialize() routine initializes the
826
** SQLite library. The sqlite3_shutdown() routine
827
** deallocates any resources that were allocated by sqlite3_initialize().
828
** This routines are designed to aid in process initialization and
829
** shutdown on embedded systems. Workstation applications using
830
** SQLite normally do not need to invoke either of these routines.
832
** A call to sqlite3_initialize() is an "effective" call if it is
833
** the first time sqlite3_initialize() is invoked during the lifetime of
834
** the process, or if it is the first time sqlite3_initialize() is invoked
835
** following a call to sqlite3_shutdown(). Only an effective call
836
** of sqlite3_initialize() does any initialization. All other calls
837
** are harmless no-ops.
839
** A call to sqlite3_shutdown() is an "effective" call if it is the first
840
** call to sqlite3_shutdown() since the last sqlite3_initialize(). Only
841
** an effective call to sqlite3_shutdown() does any deinitialization.
842
** All other valid calls to sqlite3_shutdown() are harmless no-ops.
844
** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
845
** is not. The sqlite3_shutdown() interface must only be called from a
846
** single thread. All open [database connections] must be closed and all
847
** other SQLite resources must be deallocated prior to invoking
848
** sqlite3_shutdown().
850
** Among other things, sqlite3_initialize() will invoke
851
** sqlite3_os_init(). Similarly, sqlite3_shutdown()
852
** will invoke sqlite3_os_end().
854
** The sqlite3_initialize() routine returns [SQLITE_OK] on success.
855
** If for some reason, sqlite3_initialize() is unable to initialize
856
** the library (perhaps it is unable to allocate a needed resource such
857
** as a mutex) it returns an [error code] other than [SQLITE_OK].
859
** The sqlite3_initialize() routine is called internally by many other
860
** SQLite interfaces so that an application usually does not need to
861
** invoke sqlite3_initialize() directly. For example, [sqlite3_open()]
862
** calls sqlite3_initialize() so the SQLite library will be automatically
863
** initialized when [sqlite3_open()] is called if it has not be initialized
864
** already. However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
865
** compile-time option, then the automatic calls to sqlite3_initialize()
866
** are omitted and the application must call sqlite3_initialize() directly
867
** prior to using any other SQLite interface. For maximum portability,
868
** it is recommended that applications always invoke sqlite3_initialize()
869
** directly prior to using any other SQLite interface. Future releases
870
** of SQLite may require this. In other words, the behavior exhibited
871
** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
872
** default behavior in some future release of SQLite.
874
** The sqlite3_os_init() routine does operating-system specific
875
** initialization of the SQLite library. The sqlite3_os_end()
876
** routine undoes the effect of sqlite3_os_init(). Typical tasks
877
** performed by these routines include allocation or deallocation
878
** of static resources, initialization of global variables,
879
** setting up a default [sqlite3_vfs] module, or setting up
880
** a default configuration using [sqlite3_config()].
882
** The application should never invoke either sqlite3_os_init()
883
** or sqlite3_os_end() directly. The application should only invoke
884
** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init()
885
** interface is called automatically by sqlite3_initialize() and
886
** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate
887
** implementations for sqlite3_os_init() and sqlite3_os_end()
888
** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
889
** When [custom builds | built for other platforms]
890
** (using the [SQLITE_OS_OTHER=1] compile-time
891
** option) the application must supply a suitable implementation for
892
** sqlite3_os_init() and sqlite3_os_end(). An application-supplied
893
** implementation of sqlite3_os_init() or sqlite3_os_end()
894
** must return [SQLITE_OK] on success and some other [error code] upon
897
SQLITE_API int sqlite3_initialize(void);
898
SQLITE_API int sqlite3_shutdown(void);
899
SQLITE_API int sqlite3_os_init(void);
900
SQLITE_API int sqlite3_os_end(void);
903
** CAPI3REF: Configuring The SQLite Library {H14100} <S20000><S30200>
906
** The sqlite3_config() interface is used to make global configuration
907
** changes to SQLite in order to tune SQLite to the specific needs of
908
** the application. The default configuration is recommended for most
909
** applications and so this routine is usually not necessary. It is
910
** provided to support rare applications with unusual needs.
912
** The sqlite3_config() interface is not threadsafe. The application
913
** must insure that no other SQLite interfaces are invoked by other
914
** threads while sqlite3_config() is running. Furthermore, sqlite3_config()
915
** may only be invoked prior to library initialization using
916
** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
917
** Note, however, that sqlite3_config() can be called as part of the
918
** implementation of an application-defined [sqlite3_os_init()].
920
** The first argument to sqlite3_config() is an integer
921
** [SQLITE_CONFIG_SINGLETHREAD | configuration option] that determines
922
** what property of SQLite is to be configured. Subsequent arguments
923
** vary depending on the [SQLITE_CONFIG_SINGLETHREAD | configuration option]
924
** in the first argument.
926
** When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
927
** If the option is unknown or SQLite is unable to set the option
928
** then this routine returns a non-zero [error code].
931
** [H14103] [H14106] [H14120] [H14123] [H14126] [H14129] [H14132] [H14135]
932
** [H14138] [H14141] [H14144] [H14147] [H14150] [H14153] [H14156] [H14159]
933
** [H14162] [H14165] [H14168]
935
SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_config(int, ...);
938
** CAPI3REF: Configure database connections {H14200} <S20000>
941
** The sqlite3_db_config() interface is used to make configuration
942
** changes to a [database connection]. The interface is similar to
943
** [sqlite3_config()] except that the changes apply to a single
944
** [database connection] (specified in the first argument). The
945
** sqlite3_db_config() interface can only be used immediately after
946
** the database connection is created using [sqlite3_open()],
947
** [sqlite3_open16()], or [sqlite3_open_v2()].
949
** The second argument to sqlite3_db_config(D,V,...) is the
950
** configuration verb - an integer code that indicates what
951
** aspect of the [database connection] is being configured.
952
** The only choice for this value is [SQLITE_DBCONFIG_LOOKASIDE].
953
** New verbs are likely to be added in future releases of SQLite.
954
** Additional arguments depend on the verb.
957
** [H14203] [H14206] [H14209] [H14212] [H14215]
959
SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_db_config(sqlite3*, int op, ...);
962
** CAPI3REF: Memory Allocation Routines {H10155} <S20120>
965
** An instance of this object defines the interface between SQLite
966
** and low-level memory allocation routines.
968
** This object is used in only one place in the SQLite interface.
969
** A pointer to an instance of this object is the argument to
970
** [sqlite3_config()] when the configuration option is
971
** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].
972
** By creating an instance of this object
973
** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
974
** during configuration, an application can specify an alternative
975
** memory allocation subsystem for SQLite to use for all of its
976
** dynamic memory needs.
978
** Note that SQLite comes with several [built-in memory allocators]
979
** that are perfectly adequate for the overwhelming majority of applications
980
** and that this object is only useful to a tiny minority of applications
981
** with specialized memory allocation requirements. This object is
982
** also used during testing of SQLite in order to specify an alternative
983
** memory allocator that simulates memory out-of-memory conditions in
984
** order to verify that SQLite recovers gracefully from such
987
** The xMalloc and xFree methods must work like the
988
** malloc() and free() functions from the standard C library.
989
** The xRealloc method must work like realloc() from the standard C library
990
** with the exception that if the second argument to xRealloc is zero,
991
** xRealloc must be a no-op - it must not perform any allocation or
992
** deallocation. SQLite guaranteeds that the second argument to
993
** xRealloc is always a value returned by a prior call to xRoundup.
994
** And so in cases where xRoundup always returns a positive number,
995
** xRealloc can perform exactly as the standard library realloc() and
996
** still be in compliance with this specification.
998
** xSize should return the allocated size of a memory allocation
999
** previously obtained from xMalloc or xRealloc. The allocated size
1000
** is always at least as big as the requested size but may be larger.
1002
** The xRoundup method returns what would be the allocated size of
1003
** a memory allocation given a particular requested size. Most memory
1004
** allocators round up memory allocations at least to the next multiple
1005
** of 8. Some allocators round up to a larger multiple or to a power of 2.
1006
** Every memory allocation request coming in through [sqlite3_malloc()]
1007
** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0,
1008
** that causes the corresponding memory allocation to fail.
1010
** The xInit method initializes the memory allocator. (For example,
1011
** it might allocate any require mutexes or initialize internal data
1012
** structures. The xShutdown method is invoked (indirectly) by
1013
** [sqlite3_shutdown()] and should deallocate any resources acquired
1014
** by xInit. The pAppData pointer is used as the only parameter to
1015
** xInit and xShutdown.
1017
** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes
1018
** the xInit method, so the xInit method need not be threadsafe. The
1019
** xShutdown method is only called from [sqlite3_shutdown()] so it does
1020
** not need to be threadsafe either. For all other methods, SQLite
1021
** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
1022
** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
1023
** it is by default) and so the methods are automatically serialized.
1024
** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
1025
** methods must be threadsafe or else make their own arrangements for
1028
** SQLite will never invoke xInit() more than once without an intervening
1029
** call to xShutdown().
1031
typedef struct sqlite3_mem_methods sqlite3_mem_methods;
1032
struct sqlite3_mem_methods {
1033
void *(*xMalloc)(int); /* Memory allocation function */
1034
void (*xFree)(void*); /* Free a prior allocation */
1035
void *(*xRealloc)(void*,int); /* Resize an allocation */
1036
int (*xSize)(void*); /* Return the size of an allocation */
1037
int (*xRoundup)(int); /* Round up request size to allocation size */
1038
int (*xInit)(void*); /* Initialize the memory allocator */
1039
void (*xShutdown)(void*); /* Deinitialize the memory allocator */
1040
void *pAppData; /* Argument to xInit() and xShutdown() */
1044
** CAPI3REF: Configuration Options {H10160} <S20000>
1047
** These constants are the available integer configuration options that
1048
** can be passed as the first argument to the [sqlite3_config()] interface.
1050
** New configuration options may be added in future releases of SQLite.
1051
** Existing configuration options might be discontinued. Applications
1052
** should check the return code from [sqlite3_config()] to make sure that
1053
** the call worked. The [sqlite3_config()] interface will return a
1054
** non-zero [error code] if a discontinued or unsupported configuration option
1058
** <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
1059
** <dd>There are no arguments to this option. This option disables
1060
** all mutexing and puts SQLite into a mode where it can only be used
1061
** by a single thread.</dd>
1063
** <dt>SQLITE_CONFIG_MULTITHREAD</dt>
1064
** <dd>There are no arguments to this option. This option disables
1065
** mutexing on [database connection] and [prepared statement] objects.
1066
** The application is responsible for serializing access to
1067
** [database connections] and [prepared statements]. But other mutexes
1068
** are enabled so that SQLite will be safe to use in a multi-threaded
1069
** environment as long as no two threads attempt to use the same
1070
** [database connection] at the same time. See the [threading mode]
1071
** documentation for additional information.</dd>
1073
** <dt>SQLITE_CONFIG_SERIALIZED</dt>
1074
** <dd>There are no arguments to this option. This option enables
1075
** all mutexes including the recursive
1076
** mutexes on [database connection] and [prepared statement] objects.
1077
** In this mode (which is the default when SQLite is compiled with
1078
** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
1079
** to [database connections] and [prepared statements] so that the
1080
** application is free to use the same [database connection] or the
1081
** same [prepared statement] in different threads at the same time.
1082
** See the [threading mode] documentation for additional information.</dd>
1084
** <dt>SQLITE_CONFIG_MALLOC</dt>
1085
** <dd>This option takes a single argument which is a pointer to an
1086
** instance of the [sqlite3_mem_methods] structure. The argument specifies
1087
** alternative low-level memory allocation routines to be used in place of
1088
** the memory allocation routines built into SQLite.</dd>
1090
** <dt>SQLITE_CONFIG_GETMALLOC</dt>
1091
** <dd>This option takes a single argument which is a pointer to an
1092
** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods]
1093
** structure is filled with the currently defined memory allocation routines.
1094
** This option can be used to overload the default memory allocation
1095
** routines with a wrapper that simulations memory allocation failure or
1096
** tracks memory usage, for example.</dd>
1098
** <dt>SQLITE_CONFIG_MEMSTATUS</dt>
1099
** <dd>This option takes single argument of type int, interpreted as a
1100
** boolean, which enables or disables the collection of memory allocation
1101
** statistics. When disabled, the following SQLite interfaces become
1104
** <li> [sqlite3_memory_used()]
1105
** <li> [sqlite3_memory_highwater()]
1106
** <li> [sqlite3_soft_heap_limit()]
1107
** <li> [sqlite3_status()]
1111
** <dt>SQLITE_CONFIG_SCRATCH</dt>
1112
** <dd>This option specifies a static memory buffer that SQLite can use for
1113
** scratch memory. There are three arguments: A pointer an 8-byte
1114
** aligned memory buffer from which the scrach allocations will be
1115
** drawn, the size of each scratch allocation (sz),
1116
** and the maximum number of scratch allocations (N). The sz
1117
** argument must be a multiple of 16. The sz parameter should be a few bytes
1118
** larger than the actual scratch space required due to internal overhead.
1119
** The first argument should pointer to an 8-byte aligned buffer
1120
** of at least sz*N bytes of memory.
1121
** SQLite will use no more than one scratch buffer at once per thread, so
1122
** N should be set to the expected maximum number of threads. The sz
1123
** parameter should be 6 times the size of the largest database page size.
1124
** Scratch buffers are used as part of the btree balance operation. If
1125
** The btree balancer needs additional memory beyond what is provided by
1126
** scratch buffers or if no scratch buffer space is specified, then SQLite
1127
** goes to [sqlite3_malloc()] to obtain the memory it needs.</dd>
1129
** <dt>SQLITE_CONFIG_PAGECACHE</dt>
1130
** <dd>This option specifies a static memory buffer that SQLite can use for
1131
** the database page cache with the default page cache implemenation.
1132
** This configuration should not be used if an application-define page
1133
** cache implementation is loaded using the SQLITE_CONFIG_PCACHE option.
1134
** There are three arguments to this option: A pointer to 8-byte aligned
1135
** memory, the size of each page buffer (sz), and the number of pages (N).
1136
** The sz argument should be the size of the largest database page
1137
** (a power of two between 512 and 32768) plus a little extra for each
1138
** page header. The page header size is 20 to 40 bytes depending on
1139
** the host architecture. It is harmless, apart from the wasted memory,
1140
** to make sz a little too large. The first
1141
** argument should point to an allocation of at least sz*N bytes of memory.
1142
** SQLite will use the memory provided by the first argument to satisfy its
1143
** memory needs for the first N pages that it adds to cache. If additional
1144
** page cache memory is needed beyond what is provided by this option, then
1145
** SQLite goes to [sqlite3_malloc()] for the additional storage space.
1146
** The implementation might use one or more of the N buffers to hold
1147
** memory accounting information. The pointer in the first argument must
1148
** be aligned to an 8-byte boundary or subsequent behavior of SQLite
1149
** will be undefined.</dd>
1151
** <dt>SQLITE_CONFIG_HEAP</dt>
1152
** <dd>This option specifies a static memory buffer that SQLite will use
1153
** for all of its dynamic memory allocation needs beyond those provided
1154
** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE].
1155
** There are three arguments: An 8-byte aligned pointer to the memory,
1156
** the number of bytes in the memory buffer, and the minimum allocation size.
1157
** If the first pointer (the memory pointer) is NULL, then SQLite reverts
1158
** to using its default memory allocator (the system malloc() implementation),
1159
** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. If the
1160
** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or
1161
** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory
1162
** allocator is engaged to handle all of SQLites memory allocation needs.
1163
** The first pointer (the memory pointer) must be aligned to an 8-byte
1164
** boundary or subsequent behavior of SQLite will be undefined.</dd>
1166
** <dt>SQLITE_CONFIG_MUTEX</dt>
1167
** <dd>This option takes a single argument which is a pointer to an
1168
** instance of the [sqlite3_mutex_methods] structure. The argument specifies
1169
** alternative low-level mutex routines to be used in place
1170
** the mutex routines built into SQLite.</dd>
1172
** <dt>SQLITE_CONFIG_GETMUTEX</dt>
1173
** <dd>This option takes a single argument which is a pointer to an
1174
** instance of the [sqlite3_mutex_methods] structure. The
1175
** [sqlite3_mutex_methods]
1176
** structure is filled with the currently defined mutex routines.
1177
** This option can be used to overload the default mutex allocation
1178
** routines with a wrapper used to track mutex usage for performance
1179
** profiling or testing, for example.</dd>
1181
** <dt>SQLITE_CONFIG_LOOKASIDE</dt>
1182
** <dd>This option takes two arguments that determine the default
1183
** memory allocation lookaside optimization. The first argument is the
1184
** size of each lookaside buffer slot and the second is the number of
1185
** slots allocated to each database connection. This option sets the
1186
** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
1187
** verb to [sqlite3_db_config()] can be used to change the lookaside
1188
** configuration on individual connections.</dd>
1190
** <dt>SQLITE_CONFIG_PCACHE</dt>
1191
** <dd>This option takes a single argument which is a pointer to
1192
** an [sqlite3_pcache_methods] object. This object specifies the interface
1193
** to a custom page cache implementation. SQLite makes a copy of the
1194
** object and uses it for page cache memory allocations.</dd>
1196
** <dt>SQLITE_CONFIG_GETPCACHE</dt>
1197
** <dd>This option takes a single argument which is a pointer to an
1198
** [sqlite3_pcache_methods] object. SQLite copies of the current
1199
** page cache implementation into that object.</dd>
1203
#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */
1204
#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */
1205
#define SQLITE_CONFIG_SERIALIZED 3 /* nil */
1206
#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */
1207
#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */
1208
#define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */
1209
#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */
1210
#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */
1211
#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */
1212
#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */
1213
#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */
1214
/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */
1215
#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */
1216
#define SQLITE_CONFIG_PCACHE 14 /* sqlite3_pcache_methods* */
1217
#define SQLITE_CONFIG_GETPCACHE 15 /* sqlite3_pcache_methods* */
1220
** CAPI3REF: Configuration Options {H10170} <S20000>
1223
** These constants are the available integer configuration options that
1224
** can be passed as the second argument to the [sqlite3_db_config()] interface.
1226
** New configuration options may be added in future releases of SQLite.
1227
** Existing configuration options might be discontinued. Applications
1228
** should check the return code from [sqlite3_db_config()] to make sure that
1229
** the call worked. The [sqlite3_db_config()] interface will return a
1230
** non-zero [error code] if a discontinued or unsupported configuration option
1234
** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
1235
** <dd>This option takes three additional arguments that determine the
1236
** [lookaside memory allocator] configuration for the [database connection].
1237
** The first argument (the third parameter to [sqlite3_db_config()] is a
1238
** pointer to an memory buffer to use for lookaside memory.
1239
** The first argument may be NULL in which case SQLite will allocate the
1240
** lookaside buffer itself using [sqlite3_malloc()]. The second argument is the
1241
** size of each lookaside buffer slot and the third argument is the number of
1242
** slots. The size of the buffer in the first argument must be greater than
1243
** or equal to the product of the second and third arguments. The buffer
1244
** must be aligned to an 8-byte boundary. If the second argument is not
1245
** a multiple of 8, it is internally rounded down to the next smaller
1246
** multiple of 8. See also: [SQLITE_CONFIG_LOOKASIDE]</dd>
1250
#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */
1254
** CAPI3REF: Enable Or Disable Extended Result Codes {H12200} <S10700>
1256
** The sqlite3_extended_result_codes() routine enables or disables the
1257
** [extended result codes] feature of SQLite. The extended result
1258
** codes are disabled by default for historical compatibility considerations.
1261
** [H12201] [H12202]
1263
SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff);
1266
** CAPI3REF: Last Insert Rowid {H12220} <S10700>
1268
** Each entry in an SQLite table has a unique 64-bit signed
1269
** integer key called the [ROWID | "rowid"]. The rowid is always available
1270
** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
1271
** names are not also used by explicitly declared columns. If
1272
** the table has a column of type [INTEGER PRIMARY KEY] then that column
1273
** is another alias for the rowid.
1275
** This routine returns the [rowid] of the most recent
1276
** successful [INSERT] into the database from the [database connection]
1277
** in the first argument. If no successful [INSERT]s
1278
** have ever occurred on that database connection, zero is returned.
1280
** If an [INSERT] occurs within a trigger, then the [rowid] of the inserted
1281
** row is returned by this routine as long as the trigger is running.
1282
** But once the trigger terminates, the value returned by this routine
1283
** reverts to the last value inserted before the trigger fired.
1285
** An [INSERT] that fails due to a constraint violation is not a
1286
** successful [INSERT] and does not change the value returned by this
1287
** routine. Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
1288
** and INSERT OR ABORT make no changes to the return value of this
1289
** routine when their insertion fails. When INSERT OR REPLACE
1290
** encounters a constraint violation, it does not fail. The
1291
** INSERT continues to completion after deleting rows that caused
1292
** the constraint problem so INSERT OR REPLACE will always change
1293
** the return value of this interface.
1295
** For the purposes of this routine, an [INSERT] is considered to
1296
** be successful even if it is subsequently rolled back.
1299
** [H12221] [H12223]
1301
** If a separate thread performs a new [INSERT] on the same
1302
** database connection while the [sqlite3_last_insert_rowid()]
1303
** function is running and thus changes the last insert [rowid],
1304
** then the value returned by [sqlite3_last_insert_rowid()] is
1305
** unpredictable and might not equal either the old or the new
1306
** last insert [rowid].
1308
SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
1311
** CAPI3REF: Count The Number Of Rows Modified {H12240} <S10600>
1313
** This function returns the number of database rows that were changed
1314
** or inserted or deleted by the most recently completed SQL statement
1315
** on the [database connection] specified by the first parameter.
1316
** Only changes that are directly specified by the [INSERT], [UPDATE],
1317
** or [DELETE] statement are counted. Auxiliary changes caused by
1318
** triggers or [foreign key actions] are not counted. Use the
1319
** [sqlite3_total_changes()] function to find the total number of changes
1320
** including changes caused by triggers and foreign key actions.
1322
** Changes to a view that are simulated by an [INSTEAD OF trigger]
1323
** are not counted. Only real table changes are counted.
1325
** A "row change" is a change to a single row of a single table
1326
** caused by an INSERT, DELETE, or UPDATE statement. Rows that
1327
** are changed as side effects of [REPLACE] constraint resolution,
1328
** rollback, ABORT processing, [DROP TABLE], or by any other
1329
** mechanisms do not count as direct row changes.
1331
** A "trigger context" is a scope of execution that begins and
1332
** ends with the script of a [CREATE TRIGGER | trigger].
1333
** Most SQL statements are
1334
** evaluated outside of any trigger. This is the "top level"
1335
** trigger context. If a trigger fires from the top level, a
1336
** new trigger context is entered for the duration of that one
1337
** trigger. Subtriggers create subcontexts for their duration.
1339
** Calling [sqlite3_exec()] or [sqlite3_step()] recursively does
1340
** not create a new trigger context.
1342
** This function returns the number of direct row changes in the
1343
** most recent INSERT, UPDATE, or DELETE statement within the same
1346
** Thus, when called from the top level, this function returns the
1347
** number of changes in the most recent INSERT, UPDATE, or DELETE
1348
** that also occurred at the top level. Within the body of a trigger,
1349
** the sqlite3_changes() interface can be called to find the number of
1350
** changes in the most recently completed INSERT, UPDATE, or DELETE
1351
** statement within the body of the same trigger.
1352
** However, the number returned does not include changes
1353
** caused by subtriggers since those have their own context.
1355
** See also the [sqlite3_total_changes()] interface and the
1356
** [count_changes pragma].
1359
** [H12241] [H12243]
1361
** If a separate thread makes changes on the same database connection
1362
** while [sqlite3_changes()] is running then the value returned
1363
** is unpredictable and not meaningful.
1365
SQLITE_API int sqlite3_changes(sqlite3*);
1368
** CAPI3REF: Total Number Of Rows Modified {H12260} <S10600>
1370
** This function returns the number of row changes caused by [INSERT],
1371
** [UPDATE] or [DELETE] statements since the [database connection] was opened.
1372
** The count includes all changes from all [CREATE TRIGGER | trigger]
1373
** contexts and changes made by [foreign key actions]. However,
1374
** the count does not include changes used to implement [REPLACE] constraints,
1375
** do rollbacks or ABORT processing, or [DROP TABLE] processing. The
1376
** count does not include rows of views that fire an [INSTEAD OF trigger],
1377
** though if the INSTEAD OF trigger makes changes of its own, those changes
1379
** The changes are counted as soon as the statement that makes them is
1380
** completed (when the statement handle is passed to [sqlite3_reset()] or
1381
** [sqlite3_finalize()]).
1383
** See also the [sqlite3_changes()] interface and the
1384
** [count_changes pragma].
1387
** [H12261] [H12263]
1389
** If a separate thread makes changes on the same database connection
1390
** while [sqlite3_total_changes()] is running then the value
1391
** returned is unpredictable and not meaningful.
1393
SQLITE_API int sqlite3_total_changes(sqlite3*);
1396
** CAPI3REF: Interrupt A Long-Running Query {H12270} <S30500>
1398
** This function causes any pending database operation to abort and
1399
** return at its earliest opportunity. This routine is typically
1400
** called in response to a user action such as pressing "Cancel"
1401
** or Ctrl-C where the user wants a long query operation to halt
1404
** It is safe to call this routine from a thread different from the
1405
** thread that is currently running the database operation. But it
1406
** is not safe to call this routine with a [database connection] that
1407
** is closed or might close before sqlite3_interrupt() returns.
1409
** If an SQL operation is very nearly finished at the time when
1410
** sqlite3_interrupt() is called, then it might not have an opportunity
1411
** to be interrupted and might continue to completion.
1413
** An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
1414
** If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
1415
** that is inside an explicit transaction, then the entire transaction
1416
** will be rolled back automatically.
1418
** The sqlite3_interrupt(D) call is in effect until all currently running
1419
** SQL statements on [database connection] D complete. Any new SQL statements
1420
** that are started after the sqlite3_interrupt() call and before the
1421
** running statements reaches zero are interrupted as if they had been
1422
** running prior to the sqlite3_interrupt() call. New SQL statements
1423
** that are started after the running statement count reaches zero are
1424
** not effected by the sqlite3_interrupt().
1425
** A call to sqlite3_interrupt(D) that occurs when there are no running
1426
** SQL statements is a no-op and has no effect on SQL statements
1427
** that are started after the sqlite3_interrupt() call returns.
1430
** [H12271] [H12272]
1432
** If the database connection closes while [sqlite3_interrupt()]
1433
** is running then bad things will likely happen.
1435
SQLITE_API void sqlite3_interrupt(sqlite3*);
1438
** CAPI3REF: Determine If An SQL Statement Is Complete {H10510} <S70200>
1440
** These routines are useful during command-line input to determine if the
1441
** currently entered text seems to form a complete SQL statement or
1442
** if additional input is needed before sending the text into
1443
** SQLite for parsing. These routines return 1 if the input string
1444
** appears to be a complete SQL statement. A statement is judged to be
1445
** complete if it ends with a semicolon token and is not a prefix of a
1446
** well-formed CREATE TRIGGER statement. Semicolons that are embedded within
1447
** string literals or quoted identifier names or comments are not
1448
** independent tokens (they are part of the token in which they are
1449
** embedded) and thus do not count as a statement terminator. Whitespace
1450
** and comments that follow the final semicolon are ignored.
1452
** These routines return 0 if the statement is incomplete. If a
1453
** memory allocation fails, then SQLITE_NOMEM is returned.
1455
** These routines do not parse the SQL statements thus
1456
** will not detect syntactically incorrect SQL.
1458
** If SQLite has not been initialized using [sqlite3_initialize()] prior
1459
** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
1460
** automatically by sqlite3_complete16(). If that initialization fails,
1461
** then the return value from sqlite3_complete16() will be non-zero
1462
** regardless of whether or not the input SQL is complete.
1464
** Requirements: [H10511] [H10512]
1466
** The input to [sqlite3_complete()] must be a zero-terminated
1469
** The input to [sqlite3_complete16()] must be a zero-terminated
1470
** UTF-16 string in native byte order.
1472
SQLITE_API int sqlite3_complete(const char *sql);
1473
SQLITE_API int sqlite3_complete16(const void *sql);
1476
** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors {H12310} <S40400>
1478
** This routine sets a callback function that might be invoked whenever
1479
** an attempt is made to open a database table that another thread
1480
** or process has locked.
1482
** If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]
1483
** is returned immediately upon encountering the lock. If the busy callback
1484
** is not NULL, then the callback will be invoked with two arguments.
1486
** The first argument to the handler is a copy of the void* pointer which
1487
** is the third argument to sqlite3_busy_handler(). The second argument to
1488
** the handler callback is the number of times that the busy handler has
1489
** been invoked for this locking event. If the
1490
** busy callback returns 0, then no additional attempts are made to
1491
** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned.
1492
** If the callback returns non-zero, then another attempt
1493
** is made to open the database for reading and the cycle repeats.
1495
** The presence of a busy handler does not guarantee that it will be invoked
1496
** when there is lock contention. If SQLite determines that invoking the busy
1497
** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
1498
** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler.
1499
** Consider a scenario where one process is holding a read lock that
1500
** it is trying to promote to a reserved lock and
1501
** a second process is holding a reserved lock that it is trying
1502
** to promote to an exclusive lock. The first process cannot proceed
1503
** because it is blocked by the second and the second process cannot
1504
** proceed because it is blocked by the first. If both processes
1505
** invoke the busy handlers, neither will make any progress. Therefore,
1506
** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
1507
** will induce the first process to release its read lock and allow
1508
** the second process to proceed.
1510
** The default busy callback is NULL.
1512
** The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED]
1513
** when SQLite is in the middle of a large transaction where all the
1514
** changes will not fit into the in-memory cache. SQLite will
1515
** already hold a RESERVED lock on the database file, but it needs
1516
** to promote this lock to EXCLUSIVE so that it can spill cache
1517
** pages into the database file without harm to concurrent
1518
** readers. If it is unable to promote the lock, then the in-memory
1519
** cache will be left in an inconsistent state and so the error
1520
** code is promoted from the relatively benign [SQLITE_BUSY] to
1521
** the more severe [SQLITE_IOERR_BLOCKED]. This error code promotion
1522
** forces an automatic rollback of the changes. See the
1523
** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError">
1524
** CorruptionFollowingBusyError</a> wiki page for a discussion of why
1525
** this is important.
1527
** There can only be a single busy handler defined for each
1528
** [database connection]. Setting a new busy handler clears any
1529
** previously set handler. Note that calling [sqlite3_busy_timeout()]
1530
** will also set or clear the busy handler.
1532
** The busy callback should not take any actions which modify the
1533
** database connection that invoked the busy handler. Any such actions
1534
** result in undefined behavior.
1537
** [H12311] [H12312] [H12314] [H12316] [H12318]
1539
** A busy handler must not close the database connection
1540
** or [prepared statement] that invoked the busy handler.
1542
SQLITE_API int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*);
1545
** CAPI3REF: Set A Busy Timeout {H12340} <S40410>
1547
** This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
1548
** for a specified amount of time when a table is locked. The handler
1549
** will sleep multiple times until at least "ms" milliseconds of sleeping
1550
** have accumulated. {H12343} After "ms" milliseconds of sleeping,
1551
** the handler returns 0 which causes [sqlite3_step()] to return
1552
** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED].
1554
** Calling this routine with an argument less than or equal to zero
1555
** turns off all busy handlers.
1557
** There can only be a single busy handler for a particular
1558
** [database connection] any any given moment. If another busy handler
1559
** was defined (using [sqlite3_busy_handler()]) prior to calling
1560
** this routine, that other busy handler is cleared.
1563
** [H12341] [H12343] [H12344]
1565
SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms);
1568
** CAPI3REF: Convenience Routines For Running Queries {H12370} <S10000>
1570
** Definition: A <b>result table</b> is memory data structure created by the
1571
** [sqlite3_get_table()] interface. A result table records the
1572
** complete query results from one or more queries.
1574
** The table conceptually has a number of rows and columns. But
1575
** these numbers are not part of the result table itself. These
1576
** numbers are obtained separately. Let N be the number of rows
1577
** and M be the number of columns.
1579
** A result table is an array of pointers to zero-terminated UTF-8 strings.
1580
** There are (N+1)*M elements in the array. The first M pointers point
1581
** to zero-terminated strings that contain the names of the columns.
1582
** The remaining entries all point to query results. NULL values result
1583
** in NULL pointers. All other values are in their UTF-8 zero-terminated
1584
** string representation as returned by [sqlite3_column_text()].
1586
** A result table might consist of one or more memory allocations.
1587
** It is not safe to pass a result table directly to [sqlite3_free()].
1588
** A result table should be deallocated using [sqlite3_free_table()].
1590
** As an example of the result table format, suppose a query result
1593
** <blockquote><pre>
1595
** -----------------------
1599
** </pre></blockquote>
1601
** There are two column (M==2) and three rows (N==3). Thus the
1602
** result table has 8 entries. Suppose the result table is stored
1603
** in an array names azResult. Then azResult holds this content:
1605
** <blockquote><pre>
1606
** azResult[0] = "Name";
1607
** azResult[1] = "Age";
1608
** azResult[2] = "Alice";
1609
** azResult[3] = "43";
1610
** azResult[4] = "Bob";
1611
** azResult[5] = "28";
1612
** azResult[6] = "Cindy";
1613
** azResult[7] = "21";
1614
** </pre></blockquote>
1616
** The sqlite3_get_table() function evaluates one or more
1617
** semicolon-separated SQL statements in the zero-terminated UTF-8
1618
** string of its 2nd parameter. It returns a result table to the
1619
** pointer given in its 3rd parameter.
1621
** After the calling function has finished using the result, it should
1622
** pass the pointer to the result table to sqlite3_free_table() in order to
1623
** release the memory that was malloced. Because of the way the
1624
** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
1625
** function must not try to call [sqlite3_free()] directly. Only
1626
** [sqlite3_free_table()] is able to release the memory properly and safely.
1628
** The sqlite3_get_table() interface is implemented as a wrapper around
1629
** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access
1630
** to any internal data structures of SQLite. It uses only the public
1631
** interface defined here. As a consequence, errors that occur in the
1632
** wrapper layer outside of the internal [sqlite3_exec()] call are not
1633
** reflected in subsequent calls to [sqlite3_errcode()] or [sqlite3_errmsg()].
1636
** [H12371] [H12373] [H12374] [H12376] [H12379] [H12382]
1638
SQLITE_API int sqlite3_get_table(
1639
sqlite3 *db, /* An open database */
1640
const char *zSql, /* SQL to be evaluated */
1641
char ***pazResult, /* Results of the query */
1642
int *pnRow, /* Number of result rows written here */
1643
int *pnColumn, /* Number of result columns written here */
1644
char **pzErrmsg /* Error msg written here */
1646
SQLITE_API void sqlite3_free_table(char **result);
1649
** CAPI3REF: Formatted String Printing Functions {H17400} <S70000><S20000>
1651
** These routines are work-alikes of the "printf()" family of functions
1652
** from the standard C library.
1654
** The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
1655
** results into memory obtained from [sqlite3_malloc()].
1656
** The strings returned by these two routines should be
1657
** released by [sqlite3_free()]. Both routines return a
1658
** NULL pointer if [sqlite3_malloc()] is unable to allocate enough
1659
** memory to hold the resulting string.
1661
** In sqlite3_snprintf() routine is similar to "snprintf()" from
1662
** the standard C library. The result is written into the
1663
** buffer supplied as the second parameter whose size is given by
1664
** the first parameter. Note that the order of the
1665
** first two parameters is reversed from snprintf(). This is an
1666
** historical accident that cannot be fixed without breaking
1667
** backwards compatibility. Note also that sqlite3_snprintf()
1668
** returns a pointer to its buffer instead of the number of
1669
** characters actually written into the buffer. We admit that
1670
** the number of characters written would be a more useful return
1671
** value but we cannot change the implementation of sqlite3_snprintf()
1672
** now without breaking compatibility.
1674
** As long as the buffer size is greater than zero, sqlite3_snprintf()
1675
** guarantees that the buffer is always zero-terminated. The first
1676
** parameter "n" is the total size of the buffer, including space for
1677
** the zero terminator. So the longest string that can be completely
1678
** written will be n-1 characters.
1680
** These routines all implement some additional formatting
1681
** options that are useful for constructing SQL statements.
1682
** All of the usual printf() formatting options apply. In addition, there
1683
** is are "%q", "%Q", and "%z" options.
1685
** The %q option works like %s in that it substitutes a null-terminated
1686
** string from the argument list. But %q also doubles every '\'' character.
1687
** %q is designed for use inside a string literal. By doubling each '\''
1688
** character it escapes that character and allows it to be inserted into
1691
** For example, assume the string variable zText contains text as follows:
1693
** <blockquote><pre>
1694
** char *zText = "It's a happy day!";
1695
** </pre></blockquote>
1697
** One can use this text in an SQL statement as follows:
1699
** <blockquote><pre>
1700
** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText);
1701
** sqlite3_exec(db, zSQL, 0, 0, 0);
1702
** sqlite3_free(zSQL);
1703
** </pre></blockquote>
1705
** Because the %q format string is used, the '\'' character in zText
1706
** is escaped and the SQL generated is as follows:
1708
** <blockquote><pre>
1709
** INSERT INTO table1 VALUES('It''s a happy day!')
1710
** </pre></blockquote>
1712
** This is correct. Had we used %s instead of %q, the generated SQL
1713
** would have looked like this:
1715
** <blockquote><pre>
1716
** INSERT INTO table1 VALUES('It's a happy day!');
1717
** </pre></blockquote>
1719
** This second example is an SQL syntax error. As a general rule you should
1720
** always use %q instead of %s when inserting text into a string literal.
1722
** The %Q option works like %q except it also adds single quotes around
1723
** the outside of the total string. Additionally, if the parameter in the
1724
** argument list is a NULL pointer, %Q substitutes the text "NULL" (without
1725
** single quotes) in place of the %Q option. So, for example, one could say:
1727
** <blockquote><pre>
1728
** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText);
1729
** sqlite3_exec(db, zSQL, 0, 0, 0);
1730
** sqlite3_free(zSQL);
1731
** </pre></blockquote>
1733
** The code above will render a correct SQL statement in the zSQL
1734
** variable even if the zText variable is a NULL pointer.
1736
** The "%z" formatting option works exactly like "%s" with the
1737
** addition that after the string has been read and copied into
1738
** the result, [sqlite3_free()] is called on the input string. {END}
1741
** [H17403] [H17406] [H17407]
1743
SQLITE_API char *sqlite3_mprintf(const char*,...);
1744
SQLITE_API char *sqlite3_vmprintf(const char*, va_list);
1745
SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...);
1748
** CAPI3REF: Memory Allocation Subsystem {H17300} <S20000>
1750
** The SQLite core uses these three routines for all of its own
1751
** internal memory allocation needs. "Core" in the previous sentence
1752
** does not include operating-system specific VFS implementation. The
1753
** Windows VFS uses native malloc() and free() for some operations.
1755
** The sqlite3_malloc() routine returns a pointer to a block
1756
** of memory at least N bytes in length, where N is the parameter.
1757
** If sqlite3_malloc() is unable to obtain sufficient free
1758
** memory, it returns a NULL pointer. If the parameter N to
1759
** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
1762
** Calling sqlite3_free() with a pointer previously returned
1763
** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
1764
** that it might be reused. The sqlite3_free() routine is
1765
** a no-op if is called with a NULL pointer. Passing a NULL pointer
1766
** to sqlite3_free() is harmless. After being freed, memory
1767
** should neither be read nor written. Even reading previously freed
1768
** memory might result in a segmentation fault or other severe error.
1769
** Memory corruption, a segmentation fault, or other severe error
1770
** might result if sqlite3_free() is called with a non-NULL pointer that
1771
** was not obtained from sqlite3_malloc() or sqlite3_realloc().
1773
** The sqlite3_realloc() interface attempts to resize a
1774
** prior memory allocation to be at least N bytes, where N is the
1775
** second parameter. The memory allocation to be resized is the first
1776
** parameter. If the first parameter to sqlite3_realloc()
1777
** is a NULL pointer then its behavior is identical to calling
1778
** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc().
1779
** If the second parameter to sqlite3_realloc() is zero or
1780
** negative then the behavior is exactly the same as calling
1781
** sqlite3_free(P) where P is the first parameter to sqlite3_realloc().
1782
** sqlite3_realloc() returns a pointer to a memory allocation
1783
** of at least N bytes in size or NULL if sufficient memory is unavailable.
1784
** If M is the size of the prior allocation, then min(N,M) bytes
1785
** of the prior allocation are copied into the beginning of buffer returned
1786
** by sqlite3_realloc() and the prior allocation is freed.
1787
** If sqlite3_realloc() returns NULL, then the prior allocation
1790
** The memory returned by sqlite3_malloc() and sqlite3_realloc()
1791
** is always aligned to at least an 8 byte boundary. {END}
1793
** The default implementation of the memory allocation subsystem uses
1794
** the malloc(), realloc() and free() provided by the standard C library.
1795
** {H17382} However, if SQLite is compiled with the
1796
** SQLITE_MEMORY_SIZE=<i>NNN</i> C preprocessor macro (where <i>NNN</i>
1797
** is an integer), then SQLite create a static array of at least
1798
** <i>NNN</i> bytes in size and uses that array for all of its dynamic
1799
** memory allocation needs. {END} Additional memory allocator options
1800
** may be added in future releases.
1802
** In SQLite version 3.5.0 and 3.5.1, it was possible to define
1803
** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in
1804
** implementation of these routines to be omitted. That capability
1805
** is no longer provided. Only built-in memory allocators can be used.
1807
** The Windows OS interface layer calls
1808
** the system malloc() and free() directly when converting
1809
** filenames between the UTF-8 encoding used by SQLite
1810
** and whatever filename encoding is used by the particular Windows
1811
** installation. Memory allocation errors are detected, but
1812
** they are reported back as [SQLITE_CANTOPEN] or
1813
** [SQLITE_IOERR] rather than [SQLITE_NOMEM].
1816
** [H17303] [H17304] [H17305] [H17306] [H17310] [H17312] [H17315] [H17318]
1817
** [H17321] [H17322] [H17323]
1819
** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
1820
** must be either NULL or else pointers obtained from a prior
1821
** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
1822
** not yet been released.
1824
** The application must not read or write any part of
1825
** a block of memory after it has been released using
1826
** [sqlite3_free()] or [sqlite3_realloc()].
1828
SQLITE_API void *sqlite3_malloc(int);
1829
SQLITE_API void *sqlite3_realloc(void*, int);
1830
SQLITE_API void sqlite3_free(void*);
1833
** CAPI3REF: Memory Allocator Statistics {H17370} <S30210>
1835
** SQLite provides these two interfaces for reporting on the status
1836
** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
1837
** routines, which form the built-in memory allocation subsystem.
1840
** [H17371] [H17373] [H17374] [H17375]
1842
SQLITE_API sqlite3_int64 sqlite3_memory_used(void);
1843
SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
1846
** CAPI3REF: Pseudo-Random Number Generator {H17390} <S20000>
1848
** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
1849
** select random [ROWID | ROWIDs] when inserting new records into a table that
1850
** already uses the largest possible [ROWID]. The PRNG is also used for
1851
** the build-in random() and randomblob() SQL functions. This interface allows
1852
** applications to access the same PRNG for other purposes.
1854
** A call to this routine stores N bytes of randomness into buffer P.
1856
** The first time this routine is invoked (either internally or by
1857
** the application) the PRNG is seeded using randomness obtained
1858
** from the xRandomness method of the default [sqlite3_vfs] object.
1859
** On all subsequent invocations, the pseudo-randomness is generated
1860
** internally and without recourse to the [sqlite3_vfs] xRandomness
1866
SQLITE_API void sqlite3_randomness(int N, void *P);
1869
** CAPI3REF: Compile-Time Authorization Callbacks {H12500} <S70100>
1871
** This routine registers a authorizer callback with a particular
1872
** [database connection], supplied in the first argument.
1873
** The authorizer callback is invoked as SQL statements are being compiled
1874
** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
1875
** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. At various
1876
** points during the compilation process, as logic is being created
1877
** to perform various actions, the authorizer callback is invoked to
1878
** see if those actions are allowed. The authorizer callback should
1879
** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
1880
** specific action but allow the SQL statement to continue to be
1881
** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
1882
** rejected with an error. If the authorizer callback returns
1883
** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
1884
** then the [sqlite3_prepare_v2()] or equivalent call that triggered
1885
** the authorizer will fail with an error message.
1887
** When the callback returns [SQLITE_OK], that means the operation
1888
** requested is ok. When the callback returns [SQLITE_DENY], the
1889
** [sqlite3_prepare_v2()] or equivalent call that triggered the
1890
** authorizer will fail with an error message explaining that
1891
** access is denied.
1893
** The first parameter to the authorizer callback is a copy of the third
1894
** parameter to the sqlite3_set_authorizer() interface. The second parameter
1895
** to the callback is an integer [SQLITE_COPY | action code] that specifies
1896
** the particular action to be authorized. The third through sixth parameters
1897
** to the callback are zero-terminated strings that contain additional
1898
** details about the action to be authorized.
1900
** If the action code is [SQLITE_READ]
1901
** and the callback returns [SQLITE_IGNORE] then the
1902
** [prepared statement] statement is constructed to substitute
1903
** a NULL value in place of the table column that would have
1904
** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE]
1905
** return can be used to deny an untrusted user access to individual
1906
** columns of a table.
1907
** If the action code is [SQLITE_DELETE] and the callback returns
1908
** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
1909
** [truncate optimization] is disabled and all rows are deleted individually.
1911
** An authorizer is used when [sqlite3_prepare | preparing]
1912
** SQL statements from an untrusted source, to ensure that the SQL statements
1913
** do not try to access data they are not allowed to see, or that they do not
1914
** try to execute malicious statements that damage the database. For
1915
** example, an application may allow a user to enter arbitrary
1916
** SQL queries for evaluation by a database. But the application does
1917
** not want the user to be able to make arbitrary changes to the
1918
** database. An authorizer could then be put in place while the
1919
** user-entered SQL is being [sqlite3_prepare | prepared] that
1920
** disallows everything except [SELECT] statements.
1922
** Applications that need to process SQL from untrusted sources
1923
** might also consider lowering resource limits using [sqlite3_limit()]
1924
** and limiting database size using the [max_page_count] [PRAGMA]
1925
** in addition to using an authorizer.
1927
** Only a single authorizer can be in place on a database connection
1928
** at a time. Each call to sqlite3_set_authorizer overrides the
1929
** previous call. Disable the authorizer by installing a NULL callback.
1930
** The authorizer is disabled by default.
1932
** The authorizer callback must not do anything that will modify
1933
** the database connection that invoked the authorizer callback.
1934
** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
1935
** database connections for the meaning of "modify" in this paragraph.
1937
** When [sqlite3_prepare_v2()] is used to prepare a statement, the
1938
** statement might be re-prepared during [sqlite3_step()] due to a
1939
** schema change. Hence, the application should ensure that the
1940
** correct authorizer callback remains in place during the [sqlite3_step()].
1942
** Note that the authorizer callback is invoked only during
1943
** [sqlite3_prepare()] or its variants. Authorization is not
1944
** performed during statement evaluation in [sqlite3_step()], unless
1945
** as stated in the previous paragraph, sqlite3_step() invokes
1946
** sqlite3_prepare_v2() to reprepare a statement after a schema change.
1949
** [H12501] [H12502] [H12503] [H12504] [H12505] [H12506] [H12507] [H12510]
1950
** [H12511] [H12512] [H12520] [H12521] [H12522]
1952
SQLITE_API int sqlite3_set_authorizer(
1954
int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
1959
** CAPI3REF: Authorizer Return Codes {H12590} <H12500>
1961
** The [sqlite3_set_authorizer | authorizer callback function] must
1962
** return either [SQLITE_OK] or one of these two constants in order
1963
** to signal SQLite whether or not the action is permitted. See the
1964
** [sqlite3_set_authorizer | authorizer documentation] for additional
1967
#define SQLITE_DENY 1 /* Abort the SQL statement with an error */
1968
#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */
1971
** CAPI3REF: Authorizer Action Codes {H12550} <H12500>
1973
** The [sqlite3_set_authorizer()] interface registers a callback function
1974
** that is invoked to authorize certain SQL statement actions. The
1975
** second parameter to the callback is an integer code that specifies
1976
** what action is being authorized. These are the integer action codes that
1977
** the authorizer callback may be passed.
1979
** These action code values signify what kind of operation is to be
1980
** authorized. The 3rd and 4th parameters to the authorization
1981
** callback function will be parameters or NULL depending on which of these
1982
** codes is used as the second parameter. The 5th parameter to the
1983
** authorizer callback is the name of the database ("main", "temp",
1984
** etc.) if applicable. The 6th parameter to the authorizer callback
1985
** is the name of the inner-most trigger or view that is responsible for
1986
** the access attempt or NULL if this access attempt is directly from
1987
** top-level SQL code.
1990
** [H12551] [H12552] [H12553] [H12554]
1992
/******************************************* 3rd ************ 4th ***********/
1993
#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */
1994
#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */
1995
#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */
1996
#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */
1997
#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */
1998
#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */
1999
#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */
2000
#define SQLITE_CREATE_VIEW 8 /* View Name NULL */
2001
#define SQLITE_DELETE 9 /* Table Name NULL */
2002
#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */
2003
#define SQLITE_DROP_TABLE 11 /* Table Name NULL */
2004
#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */
2005
#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */
2006
#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */
2007
#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */
2008
#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */
2009
#define SQLITE_DROP_VIEW 17 /* View Name NULL */
2010
#define SQLITE_INSERT 18 /* Table Name NULL */
2011
#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */
2012
#define SQLITE_READ 20 /* Table Name Column Name */
2013
#define SQLITE_SELECT 21 /* NULL NULL */
2014
#define SQLITE_TRANSACTION 22 /* Operation NULL */
2015
#define SQLITE_UPDATE 23 /* Table Name Column Name */
2016
#define SQLITE_ATTACH 24 /* Filename NULL */
2017
#define SQLITE_DETACH 25 /* Database Name NULL */
2018
#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */
2019
#define SQLITE_REINDEX 27 /* Index Name NULL */
2020
#define SQLITE_ANALYZE 28 /* Table Name NULL */
2021
#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */
2022
#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */
2023
#define SQLITE_FUNCTION 31 /* NULL Function Name */
2024
#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */
2025
#define SQLITE_COPY 0 /* No longer used */
2028
** CAPI3REF: Tracing And Profiling Functions {H12280} <S60400>
2031
** These routines register callback functions that can be used for
2032
** tracing and profiling the execution of SQL statements.
2034
** The callback function registered by sqlite3_trace() is invoked at
2035
** various times when an SQL statement is being run by [sqlite3_step()].
2036
** The callback returns a UTF-8 rendering of the SQL statement text
2037
** as the statement first begins executing. Additional callbacks occur
2038
** as each triggered subprogram is entered. The callbacks for triggers
2039
** contain a UTF-8 SQL comment that identifies the trigger.
2041
** The callback function registered by sqlite3_profile() is invoked
2042
** as each SQL statement finishes. The profile callback contains
2043
** the original statement text and an estimate of wall-clock time
2044
** of how long that statement took to run.
2047
** [H12281] [H12282] [H12283] [H12284] [H12285] [H12287] [H12288] [H12289]
2050
SQLITE_API SQLITE_EXPERIMENTAL void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*);
2051
SQLITE_API SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*,
2052
void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
2055
** CAPI3REF: Query Progress Callbacks {H12910} <S60400>
2057
** This routine configures a callback function - the
2058
** progress callback - that is invoked periodically during long
2059
** running calls to [sqlite3_exec()], [sqlite3_step()] and
2060
** [sqlite3_get_table()]. An example use for this
2061
** interface is to keep a GUI updated during a large query.
2063
** If the progress callback returns non-zero, the operation is
2064
** interrupted. This feature can be used to implement a
2065
** "Cancel" button on a GUI progress dialog box.
2067
** The progress handler must not do anything that will modify
2068
** the database connection that invoked the progress handler.
2069
** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2070
** database connections for the meaning of "modify" in this paragraph.
2073
** [H12911] [H12912] [H12913] [H12914] [H12915] [H12916] [H12917] [H12918]
2076
SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
2079
** CAPI3REF: Opening A New Database Connection {H12700} <S40200>
2081
** These routines open an SQLite database file whose name is given by the
2082
** filename argument. The filename argument is interpreted as UTF-8 for
2083
** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
2084
** order for sqlite3_open16(). A [database connection] handle is usually
2085
** returned in *ppDb, even if an error occurs. The only exception is that
2086
** if SQLite is unable to allocate memory to hold the [sqlite3] object,
2087
** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
2088
** object. If the database is opened (and/or created) successfully, then
2089
** [SQLITE_OK] is returned. Otherwise an [error code] is returned. The
2090
** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
2091
** an English language description of the error.
2093
** The default encoding for the database will be UTF-8 if
2094
** sqlite3_open() or sqlite3_open_v2() is called and
2095
** UTF-16 in the native byte order if sqlite3_open16() is used.
2097
** Whether or not an error occurs when it is opened, resources
2098
** associated with the [database connection] handle should be released by
2099
** passing it to [sqlite3_close()] when it is no longer required.
2101
** The sqlite3_open_v2() interface works like sqlite3_open()
2102
** except that it accepts two additional parameters for additional control
2103
** over the new database connection. The flags parameter can take one of
2104
** the following three values, optionally combined with the
2105
** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE],
2106
** and/or [SQLITE_OPEN_PRIVATECACHE] flags:
2109
** <dt>[SQLITE_OPEN_READONLY]</dt>
2110
** <dd>The database is opened in read-only mode. If the database does not
2111
** already exist, an error is returned.</dd>
2113
** <dt>[SQLITE_OPEN_READWRITE]</dt>
2114
** <dd>The database is opened for reading and writing if possible, or reading
2115
** only if the file is write protected by the operating system. In either
2116
** case the database must already exist, otherwise an error is returned.</dd>
2118
** <dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
2119
** <dd>The database is opened for reading and writing, and is creates it if
2120
** it does not already exist. This is the behavior that is always used for
2121
** sqlite3_open() and sqlite3_open16().</dd>
2124
** If the 3rd parameter to sqlite3_open_v2() is not one of the
2125
** combinations shown above or one of the combinations shown above combined
2126
** with the [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX],
2127
** [SQLITE_OPEN_SHAREDCACHE] and/or [SQLITE_OPEN_SHAREDCACHE] flags,
2128
** then the behavior is undefined.
2130
** If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection
2131
** opens in the multi-thread [threading mode] as long as the single-thread
2132
** mode has not been set at compile-time or start-time. If the
2133
** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens
2134
** in the serialized [threading mode] unless single-thread was
2135
** previously selected at compile-time or start-time.
2136
** The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be
2137
** eligible to use [shared cache mode], regardless of whether or not shared
2138
** cache is enabled using [sqlite3_enable_shared_cache()]. The
2139
** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not
2140
** participate in [shared cache mode] even if it is enabled.
2142
** If the filename is ":memory:", then a private, temporary in-memory database
2143
** is created for the connection. This in-memory database will vanish when
2144
** the database connection is closed. Future versions of SQLite might
2145
** make use of additional special filenames that begin with the ":" character.
2146
** It is recommended that when a database filename actually does begin with
2147
** a ":" character you should prefix the filename with a pathname such as
2148
** "./" to avoid ambiguity.
2150
** If the filename is an empty string, then a private, temporary
2151
** on-disk database will be created. This private database will be
2152
** automatically deleted as soon as the database connection is closed.
2154
** The fourth parameter to sqlite3_open_v2() is the name of the
2155
** [sqlite3_vfs] object that defines the operating system interface that
2156
** the new database connection should use. If the fourth parameter is
2157
** a NULL pointer then the default [sqlite3_vfs] object is used.
2159
** <b>Note to Windows users:</b> The encoding used for the filename argument
2160
** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
2161
** codepage is currently defined. Filenames containing international
2162
** characters must be converted to UTF-8 prior to passing them into
2163
** sqlite3_open() or sqlite3_open_v2().
2166
** [H12701] [H12702] [H12703] [H12704] [H12706] [H12707] [H12709] [H12711]
2167
** [H12712] [H12713] [H12714] [H12717] [H12719] [H12721] [H12723]
2169
SQLITE_API int sqlite3_open(
2170
const char *filename, /* Database filename (UTF-8) */
2171
sqlite3 **ppDb /* OUT: SQLite db handle */
2173
SQLITE_API int sqlite3_open16(
2174
const void *filename, /* Database filename (UTF-16) */
2175
sqlite3 **ppDb /* OUT: SQLite db handle */
2177
SQLITE_API int sqlite3_open_v2(
2178
const char *filename, /* Database filename (UTF-8) */
2179
sqlite3 **ppDb, /* OUT: SQLite db handle */
2180
int flags, /* Flags */
2181
const char *zVfs /* Name of VFS module to use */
2185
** CAPI3REF: Error Codes And Messages {H12800} <S60200>
2187
** The sqlite3_errcode() interface returns the numeric [result code] or
2188
** [extended result code] for the most recent failed sqlite3_* API call
2189
** associated with a [database connection]. If a prior API call failed
2190
** but the most recent API call succeeded, the return value from
2191
** sqlite3_errcode() is undefined. The sqlite3_extended_errcode()
2192
** interface is the same except that it always returns the
2193
** [extended result code] even when extended result codes are
2196
** The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
2197
** text that describes the error, as either UTF-8 or UTF-16 respectively.
2198
** Memory to hold the error message string is managed internally.
2199
** The application does not need to worry about freeing the result.
2200
** However, the error string might be overwritten or deallocated by
2201
** subsequent calls to other SQLite interface functions.
2203
** When the serialized [threading mode] is in use, it might be the
2204
** case that a second error occurs on a separate thread in between
2205
** the time of the first error and the call to these interfaces.
2206
** When that happens, the second error will be reported since these
2207
** interfaces always report the most recent result. To avoid
2208
** this, each thread can obtain exclusive use of the [database connection] D
2209
** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
2210
** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
2211
** all calls to the interfaces listed here are completed.
2213
** If an interface fails with SQLITE_MISUSE, that means the interface
2214
** was invoked incorrectly by the application. In that case, the
2215
** error code and message may or may not be set.
2218
** [H12801] [H12802] [H12803] [H12807] [H12808] [H12809]
2220
SQLITE_API int sqlite3_errcode(sqlite3 *db);
2221
SQLITE_API int sqlite3_extended_errcode(sqlite3 *db);
2222
SQLITE_API const char *sqlite3_errmsg(sqlite3*);
2223
SQLITE_API const void *sqlite3_errmsg16(sqlite3*);
2226
** CAPI3REF: SQL Statement Object {H13000} <H13010>
2227
** KEYWORDS: {prepared statement} {prepared statements}
2229
** An instance of this object represents a single SQL statement.
2230
** This object is variously known as a "prepared statement" or a
2231
** "compiled SQL statement" or simply as a "statement".
2233
** The life of a statement object goes something like this:
2236
** <li> Create the object using [sqlite3_prepare_v2()] or a related
2238
** <li> Bind values to [host parameters] using the sqlite3_bind_*()
2240
** <li> Run the SQL by calling [sqlite3_step()] one or more times.
2241
** <li> Reset the statement using [sqlite3_reset()] then go back
2242
** to step 2. Do this zero or more times.
2243
** <li> Destroy the object using [sqlite3_finalize()].
2246
** Refer to documentation on individual methods above for additional
2249
typedef struct sqlite3_stmt sqlite3_stmt;
2252
** CAPI3REF: Run-time Limits {H12760} <S20600>
2254
** This interface allows the size of various constructs to be limited
2255
** on a connection by connection basis. The first parameter is the
2256
** [database connection] whose limit is to be set or queried. The
2257
** second parameter is one of the [limit categories] that define a
2258
** class of constructs to be size limited. The third parameter is the
2259
** new limit for that construct. The function returns the old limit.
2261
** If the new limit is a negative number, the limit is unchanged.
2262
** For the limit category of SQLITE_LIMIT_XYZ there is a
2263
** [limits | hard upper bound]
2264
** set by a compile-time C preprocessor macro named
2265
** [limits | SQLITE_MAX_XYZ].
2266
** (The "_LIMIT_" in the name is changed to "_MAX_".)
2267
** Attempts to increase a limit above its hard upper bound are
2268
** silently truncated to the hard upper limit.
2270
** Run time limits are intended for use in applications that manage
2271
** both their own internal database and also databases that are controlled
2272
** by untrusted external sources. An example application might be a
2273
** web browser that has its own databases for storing history and
2274
** separate databases controlled by JavaScript applications downloaded
2275
** off the Internet. The internal databases can be given the
2276
** large, default limits. Databases managed by external sources can
2277
** be given much smaller limits designed to prevent a denial of service
2278
** attack. Developers might also want to use the [sqlite3_set_authorizer()]
2279
** interface to further control untrusted SQL. The size of the database
2280
** created by an untrusted script can be contained using the
2281
** [max_page_count] [PRAGMA].
2283
** New run-time limit categories may be added in future releases.
2286
** [H12762] [H12766] [H12769]
2288
SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal);
2291
** CAPI3REF: Run-Time Limit Categories {H12790} <H12760>
2292
** KEYWORDS: {limit category} {*limit categories}
2294
** These constants define various performance limits
2295
** that can be lowered at run-time using [sqlite3_limit()].
2296
** The synopsis of the meanings of the various limits is shown below.
2297
** Additional information is available at [limits | Limits in SQLite].
2300
** <dt>SQLITE_LIMIT_LENGTH</dt>
2301
** <dd>The maximum size of any string or BLOB or table row.<dd>
2303
** <dt>SQLITE_LIMIT_SQL_LENGTH</dt>
2304
** <dd>The maximum length of an SQL statement.</dd>
2306
** <dt>SQLITE_LIMIT_COLUMN</dt>
2307
** <dd>The maximum number of columns in a table definition or in the
2308
** result set of a [SELECT] or the maximum number of columns in an index
2309
** or in an ORDER BY or GROUP BY clause.</dd>
2311
** <dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
2312
** <dd>The maximum depth of the parse tree on any expression.</dd>
2314
** <dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
2315
** <dd>The maximum number of terms in a compound SELECT statement.</dd>
2317
** <dt>SQLITE_LIMIT_VDBE_OP</dt>
2318
** <dd>The maximum number of instructions in a virtual machine program
2319
** used to implement an SQL statement.</dd>
2321
** <dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
2322
** <dd>The maximum number of arguments on a function.</dd>
2324
** <dt>SQLITE_LIMIT_ATTACHED</dt>
2325
** <dd>The maximum number of [ATTACH | attached databases].</dd>
2327
** <dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
2328
** <dd>The maximum length of the pattern argument to the [LIKE] or
2329
** [GLOB] operators.</dd>
2331
** <dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
2332
** <dd>The maximum number of variables in an SQL statement that can
2335
** <dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
2336
** <dd>The maximum depth of recursion for triggers.</dd>
2339
#define SQLITE_LIMIT_LENGTH 0
2340
#define SQLITE_LIMIT_SQL_LENGTH 1
2341
#define SQLITE_LIMIT_COLUMN 2
2342
#define SQLITE_LIMIT_EXPR_DEPTH 3
2343
#define SQLITE_LIMIT_COMPOUND_SELECT 4
2344
#define SQLITE_LIMIT_VDBE_OP 5
2345
#define SQLITE_LIMIT_FUNCTION_ARG 6
2346
#define SQLITE_LIMIT_ATTACHED 7
2347
#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8
2348
#define SQLITE_LIMIT_VARIABLE_NUMBER 9
2349
#define SQLITE_LIMIT_TRIGGER_DEPTH 10
2352
** CAPI3REF: Compiling An SQL Statement {H13010} <S10000>
2353
** KEYWORDS: {SQL statement compiler}
2355
** To execute an SQL query, it must first be compiled into a byte-code
2356
** program using one of these routines.
2358
** The first argument, "db", is a [database connection] obtained from a
2359
** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
2360
** [sqlite3_open16()]. The database connection must not have been closed.
2362
** The second argument, "zSql", is the statement to be compiled, encoded
2363
** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2()
2364
** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2()
2367
** If the nByte argument is less than zero, then zSql is read up to the
2368
** first zero terminator. If nByte is non-negative, then it is the maximum
2369
** number of bytes read from zSql. When nByte is non-negative, the
2370
** zSql string ends at either the first '\000' or '\u0000' character or
2371
** the nByte-th byte, whichever comes first. If the caller knows
2372
** that the supplied string is nul-terminated, then there is a small
2373
** performance advantage to be gained by passing an nByte parameter that
2374
** is equal to the number of bytes in the input string <i>including</i>
2375
** the nul-terminator bytes.
2377
** If pzTail is not NULL then *pzTail is made to point to the first byte
2378
** past the end of the first SQL statement in zSql. These routines only
2379
** compile the first statement in zSql, so *pzTail is left pointing to
2380
** what remains uncompiled.
2382
** *ppStmt is left pointing to a compiled [prepared statement] that can be
2383
** executed using [sqlite3_step()]. If there is an error, *ppStmt is set
2384
** to NULL. If the input text contains no SQL (if the input is an empty
2385
** string or a comment) then *ppStmt is set to NULL.
2386
** The calling procedure is responsible for deleting the compiled
2387
** SQL statement using [sqlite3_finalize()] after it has finished with it.
2388
** ppStmt may not be NULL.
2390
** On success, [SQLITE_OK] is returned, otherwise an [error code] is returned.
2392
** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are
2393
** recommended for all new programs. The two older interfaces are retained
2394
** for backwards compatibility, but their use is discouraged.
2395
** In the "v2" interfaces, the prepared statement
2396
** that is returned (the [sqlite3_stmt] object) contains a copy of the
2397
** original SQL text. This causes the [sqlite3_step()] interface to
2398
** behave a differently in three ways:
2402
** If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
2403
** always used to do, [sqlite3_step()] will automatically recompile the SQL
2404
** statement and try to run it again. If the schema has changed in
2405
** a way that makes the statement no longer valid, [sqlite3_step()] will still
2406
** return [SQLITE_SCHEMA]. But unlike the legacy behavior, [SQLITE_SCHEMA] is
2407
** now a fatal error. Calling [sqlite3_prepare_v2()] again will not make the
2408
** error go away. Note: use [sqlite3_errmsg()] to find the text
2409
** of the parsing error that results in an [SQLITE_SCHEMA] return.
2413
** When an error occurs, [sqlite3_step()] will return one of the detailed
2414
** [error codes] or [extended error codes]. The legacy behavior was that
2415
** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
2416
** and you would have to make a second call to [sqlite3_reset()] in order
2417
** to find the underlying cause of the problem. With the "v2" prepare
2418
** interfaces, the underlying reason for the error is returned immediately.
2422
** ^If the value of a [parameter | host parameter] in the WHERE clause might
2423
** change the query plan for a statement, then the statement may be
2424
** automatically recompiled (as if there had been a schema change) on the first
2425
** [sqlite3_step()] call following any change to the
2426
** [sqlite3_bind_text | bindings] of the [parameter].
2431
** [H13011] [H13012] [H13013] [H13014] [H13015] [H13016] [H13019] [H13021]
2434
SQLITE_API int sqlite3_prepare(
2435
sqlite3 *db, /* Database handle */
2436
const char *zSql, /* SQL statement, UTF-8 encoded */
2437
int nByte, /* Maximum length of zSql in bytes. */
2438
sqlite3_stmt **ppStmt, /* OUT: Statement handle */
2439
const char **pzTail /* OUT: Pointer to unused portion of zSql */
2441
SQLITE_API int sqlite3_prepare_v2(
2442
sqlite3 *db, /* Database handle */
2443
const char *zSql, /* SQL statement, UTF-8 encoded */
2444
int nByte, /* Maximum length of zSql in bytes. */
2445
sqlite3_stmt **ppStmt, /* OUT: Statement handle */
2446
const char **pzTail /* OUT: Pointer to unused portion of zSql */
2448
SQLITE_API int sqlite3_prepare16(
2449
sqlite3 *db, /* Database handle */
2450
const void *zSql, /* SQL statement, UTF-16 encoded */
2451
int nByte, /* Maximum length of zSql in bytes. */
2452
sqlite3_stmt **ppStmt, /* OUT: Statement handle */
2453
const void **pzTail /* OUT: Pointer to unused portion of zSql */
2455
SQLITE_API int sqlite3_prepare16_v2(
2456
sqlite3 *db, /* Database handle */
2457
const void *zSql, /* SQL statement, UTF-16 encoded */
2458
int nByte, /* Maximum length of zSql in bytes. */
2459
sqlite3_stmt **ppStmt, /* OUT: Statement handle */
2460
const void **pzTail /* OUT: Pointer to unused portion of zSql */
2464
** CAPI3REF: Retrieving Statement SQL {H13100} <H13000>
2466
** This interface can be used to retrieve a saved copy of the original
2467
** SQL text used to create a [prepared statement] if that statement was
2468
** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()].
2471
** [H13101] [H13102] [H13103]
2473
SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt);
2476
** CAPI3REF: Dynamically Typed Value Object {H15000} <S20200>
2477
** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
2479
** SQLite uses the sqlite3_value object to represent all values
2480
** that can be stored in a database table. SQLite uses dynamic typing
2481
** for the values it stores. Values stored in sqlite3_value objects
2482
** can be integers, floating point values, strings, BLOBs, or NULL.
2484
** An sqlite3_value object may be either "protected" or "unprotected".
2485
** Some interfaces require a protected sqlite3_value. Other interfaces
2486
** will accept either a protected or an unprotected sqlite3_value.
2487
** Every interface that accepts sqlite3_value arguments specifies
2488
** whether or not it requires a protected sqlite3_value.
2490
** The terms "protected" and "unprotected" refer to whether or not
2491
** a mutex is held. A internal mutex is held for a protected
2492
** sqlite3_value object but no mutex is held for an unprotected
2493
** sqlite3_value object. If SQLite is compiled to be single-threaded
2494
** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
2495
** or if SQLite is run in one of reduced mutex modes
2496
** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
2497
** then there is no distinction between protected and unprotected
2498
** sqlite3_value objects and they can be used interchangeably. However,
2499
** for maximum code portability it is recommended that applications
2500
** still make the distinction between between protected and unprotected
2501
** sqlite3_value objects even when not strictly required.
2503
** The sqlite3_value objects that are passed as parameters into the
2504
** implementation of [application-defined SQL functions] are protected.
2505
** The sqlite3_value object returned by
2506
** [sqlite3_column_value()] is unprotected.
2507
** Unprotected sqlite3_value objects may only be used with
2508
** [sqlite3_result_value()] and [sqlite3_bind_value()].
2509
** The [sqlite3_value_blob | sqlite3_value_type()] family of
2510
** interfaces require protected sqlite3_value objects.
2512
typedef struct Mem sqlite3_value;
2515
** CAPI3REF: SQL Function Context Object {H16001} <S20200>
2517
** The context in which an SQL function executes is stored in an
2518
** sqlite3_context object. A pointer to an sqlite3_context object
2519
** is always first parameter to [application-defined SQL functions].
2520
** The application-defined SQL function implementation will pass this
2521
** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
2522
** [sqlite3_aggregate_context()], [sqlite3_user_data()],
2523
** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
2524
** and/or [sqlite3_set_auxdata()].
2526
typedef struct sqlite3_context sqlite3_context;
2529
** CAPI3REF: Binding Values To Prepared Statements {H13500} <S70300>
2530
** KEYWORDS: {host parameter} {host parameters} {host parameter name}
2531
** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
2533
** In the SQL strings input to [sqlite3_prepare_v2()] and its variants,
2534
** literals may be replaced by a [parameter] that matches one of following
2545
** In the templates above, NNN represents an integer literal,
2546
** and VVV represents an alphanumeric identifer. The values of these
2547
** parameters (also called "host parameter names" or "SQL parameters")
2548
** can be set using the sqlite3_bind_*() routines defined here.
2550
** The first argument to the sqlite3_bind_*() routines is always
2551
** a pointer to the [sqlite3_stmt] object returned from
2552
** [sqlite3_prepare_v2()] or its variants.
2554
** The second argument is the index of the SQL parameter to be set.
2555
** The leftmost SQL parameter has an index of 1. When the same named
2556
** SQL parameter is used more than once, second and subsequent
2557
** occurrences have the same index as the first occurrence.
2558
** The index for named parameters can be looked up using the
2559
** [sqlite3_bind_parameter_index()] API if desired. The index
2560
** for "?NNN" parameters is the value of NNN.
2561
** The NNN value must be between 1 and the [sqlite3_limit()]
2562
** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999).
2564
** The third argument is the value to bind to the parameter.
2566
** In those routines that have a fourth argument, its value is the
2567
** number of bytes in the parameter. To be clear: the value is the
2568
** number of <u>bytes</u> in the value, not the number of characters.
2569
** If the fourth parameter is negative, the length of the string is
2570
** the number of bytes up to the first zero terminator.
2572
** The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and
2573
** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or
2574
** string after SQLite has finished with it. If the fifth argument is
2575
** the special value [SQLITE_STATIC], then SQLite assumes that the
2576
** information is in static, unmanaged space and does not need to be freed.
2577
** If the fifth argument has the value [SQLITE_TRANSIENT], then
2578
** SQLite makes its own private copy of the data immediately, before
2579
** the sqlite3_bind_*() routine returns.
2581
** The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
2582
** is filled with zeroes. A zeroblob uses a fixed amount of memory
2583
** (just an integer to hold its size) while it is being processed.
2584
** Zeroblobs are intended to serve as placeholders for BLOBs whose
2585
** content is later written using
2586
** [sqlite3_blob_open | incremental BLOB I/O] routines.
2587
** A negative value for the zeroblob results in a zero-length BLOB.
2589
** The sqlite3_bind_*() routines must be called after
2590
** [sqlite3_prepare_v2()] (and its variants) or [sqlite3_reset()] and
2591
** before [sqlite3_step()].
2592
** Bindings are not cleared by the [sqlite3_reset()] routine.
2593
** Unbound parameters are interpreted as NULL.
2595
** These routines return [SQLITE_OK] on success or an error code if
2596
** anything goes wrong. [SQLITE_RANGE] is returned if the parameter
2597
** index is out of range. [SQLITE_NOMEM] is returned if malloc() fails.
2598
** [SQLITE_MISUSE] might be returned if these routines are called on a
2599
** virtual machine that is the wrong state or which has already been finalized.
2600
** Detection of misuse is unreliable. Applications should not depend
2601
** on SQLITE_MISUSE returns. SQLITE_MISUSE is intended to indicate a
2602
** a logic error in the application. Future versions of SQLite might
2603
** panic rather than return SQLITE_MISUSE.
2605
** See also: [sqlite3_bind_parameter_count()],
2606
** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
2609
** [H13506] [H13509] [H13512] [H13515] [H13518] [H13521] [H13524] [H13527]
2610
** [H13530] [H13533] [H13536] [H13539] [H13542] [H13545] [H13548] [H13551]
2613
SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
2614
SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double);
2615
SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int);
2616
SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
2617
SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int);
2618
SQLITE_API int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*));
2619
SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
2620
SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
2621
SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
2624
** CAPI3REF: Number Of SQL Parameters {H13600} <S70300>
2626
** This routine can be used to find the number of [SQL parameters]
2627
** in a [prepared statement]. SQL parameters are tokens of the
2628
** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
2629
** placeholders for values that are [sqlite3_bind_blob | bound]
2630
** to the parameters at a later time.
2632
** This routine actually returns the index of the largest (rightmost)
2633
** parameter. For all forms except ?NNN, this will correspond to the
2634
** number of unique parameters. If parameters of the ?NNN are used,
2635
** there may be gaps in the list.
2637
** See also: [sqlite3_bind_blob|sqlite3_bind()],
2638
** [sqlite3_bind_parameter_name()], and
2639
** [sqlite3_bind_parameter_index()].
2644
SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*);
2647
** CAPI3REF: Name Of A Host Parameter {H13620} <S70300>
2649
** This routine returns a pointer to the name of the n-th
2650
** [SQL parameter] in a [prepared statement].
2651
** SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
2652
** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
2654
** In other words, the initial ":" or "$" or "@" or "?"
2655
** is included as part of the name.
2656
** Parameters of the form "?" without a following integer have no name
2657
** and are also referred to as "anonymous parameters".
2659
** The first host parameter has an index of 1, not 0.
2661
** If the value n is out of range or if the n-th parameter is
2662
** nameless, then NULL is returned. The returned string is
2663
** always in UTF-8 encoding even if the named parameter was
2664
** originally specified as UTF-16 in [sqlite3_prepare16()] or
2665
** [sqlite3_prepare16_v2()].
2667
** See also: [sqlite3_bind_blob|sqlite3_bind()],
2668
** [sqlite3_bind_parameter_count()], and
2669
** [sqlite3_bind_parameter_index()].
2674
SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
2677
** CAPI3REF: Index Of A Parameter With A Given Name {H13640} <S70300>
2679
** Return the index of an SQL parameter given its name. The
2680
** index value returned is suitable for use as the second
2681
** parameter to [sqlite3_bind_blob|sqlite3_bind()]. A zero
2682
** is returned if no matching parameter is found. The parameter
2683
** name must be given in UTF-8 even if the original statement
2684
** was prepared from UTF-16 text using [sqlite3_prepare16_v2()].
2686
** See also: [sqlite3_bind_blob|sqlite3_bind()],
2687
** [sqlite3_bind_parameter_count()], and
2688
** [sqlite3_bind_parameter_index()].
2693
SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
2696
** CAPI3REF: Reset All Bindings On A Prepared Statement {H13660} <S70300>
2698
** Contrary to the intuition of many, [sqlite3_reset()] does not reset
2699
** the [sqlite3_bind_blob | bindings] on a [prepared statement].
2700
** Use this routine to reset all host parameters to NULL.
2705
SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*);
2708
** CAPI3REF: Number Of Columns In A Result Set {H13710} <S10700>
2710
** Return the number of columns in the result set returned by the
2711
** [prepared statement]. This routine returns 0 if pStmt is an SQL
2712
** statement that does not return data (for example an [UPDATE]).
2717
SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt);
2720
** CAPI3REF: Column Names In A Result Set {H13720} <S10700>
2722
** These routines return the name assigned to a particular column
2723
** in the result set of a [SELECT] statement. The sqlite3_column_name()
2724
** interface returns a pointer to a zero-terminated UTF-8 string
2725
** and sqlite3_column_name16() returns a pointer to a zero-terminated
2726
** UTF-16 string. The first parameter is the [prepared statement]
2727
** that implements the [SELECT] statement. The second parameter is the
2728
** column number. The leftmost column is number 0.
2730
** The returned string pointer is valid until either the [prepared statement]
2731
** is destroyed by [sqlite3_finalize()] or until the next call to
2732
** sqlite3_column_name() or sqlite3_column_name16() on the same column.
2734
** If sqlite3_malloc() fails during the processing of either routine
2735
** (for example during a conversion from UTF-8 to UTF-16) then a
2736
** NULL pointer is returned.
2738
** The name of a result column is the value of the "AS" clause for
2739
** that column, if there is an AS clause. If there is no AS clause
2740
** then the name of the column is unspecified and may change from
2741
** one release of SQLite to the next.
2744
** [H13721] [H13723] [H13724] [H13725] [H13726] [H13727]
2746
SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N);
2747
SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N);
2750
** CAPI3REF: Source Of Data In A Query Result {H13740} <S10700>
2752
** These routines provide a means to determine what column of what
2753
** table in which database a result of a [SELECT] statement comes from.
2754
** The name of the database or table or column can be returned as
2755
** either a UTF-8 or UTF-16 string. The _database_ routines return
2756
** the database name, the _table_ routines return the table name, and
2757
** the origin_ routines return the column name.
2758
** The returned string is valid until the [prepared statement] is destroyed
2759
** using [sqlite3_finalize()] or until the same information is requested
2760
** again in a different encoding.
2762
** The names returned are the original un-aliased names of the
2763
** database, table, and column.
2765
** The first argument to the following calls is a [prepared statement].
2766
** These functions return information about the Nth column returned by
2767
** the statement, where N is the second function argument.
2769
** If the Nth column returned by the statement is an expression or
2770
** subquery and is not a column value, then all of these functions return
2771
** NULL. These routine might also return NULL if a memory allocation error
2772
** occurs. Otherwise, they return the name of the attached database, table
2773
** and column that query result column was extracted from.
2775
** As with all other SQLite APIs, those postfixed with "16" return
2776
** UTF-16 encoded strings, the other functions return UTF-8. {END}
2778
** These APIs are only available if the library was compiled with the
2779
** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined.
2782
** If two or more threads call one or more of these routines against the same
2783
** prepared statement and column at the same time then the results are
2787
** [H13741] [H13742] [H13743] [H13744] [H13745] [H13746] [H13748]
2789
** If two or more threads call one or more
2790
** [sqlite3_column_database_name | column metadata interfaces]
2791
** for the same [prepared statement] and result column
2792
** at the same time then the results are undefined.
2794
SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int);
2795
SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
2796
SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int);
2797
SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
2798
SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
2799
SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
2802
** CAPI3REF: Declared Datatype Of A Query Result {H13760} <S10700>
2804
** The first parameter is a [prepared statement].
2805
** If this statement is a [SELECT] statement and the Nth column of the
2806
** returned result set of that [SELECT] is a table column (not an
2807
** expression or subquery) then the declared type of the table
2808
** column is returned. If the Nth column of the result set is an
2809
** expression or subquery, then a NULL pointer is returned.
2810
** The returned string is always UTF-8 encoded. {END}
2812
** For example, given the database schema:
2814
** CREATE TABLE t1(c1 VARIANT);
2816
** and the following statement to be compiled:
2818
** SELECT c1 + 1, c1 FROM t1;
2820
** this routine would return the string "VARIANT" for the second result
2821
** column (i==1), and a NULL pointer for the first result column (i==0).
2823
** SQLite uses dynamic run-time typing. So just because a column
2824
** is declared to contain a particular type does not mean that the
2825
** data stored in that column is of the declared type. SQLite is
2826
** strongly typed, but the typing is dynamic not static. Type
2827
** is associated with individual values, not with the containers
2828
** used to hold those values.
2831
** [H13761] [H13762] [H13763]
2833
SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int);
2834
SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
2837
** CAPI3REF: Evaluate An SQL Statement {H13200} <S10000>
2839
** After a [prepared statement] has been prepared using either
2840
** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy
2841
** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
2842
** must be called one or more times to evaluate the statement.
2844
** The details of the behavior of the sqlite3_step() interface depend
2845
** on whether the statement was prepared using the newer "v2" interface
2846
** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy
2847
** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the
2848
** new "v2" interface is recommended for new applications but the legacy
2849
** interface will continue to be supported.
2851
** In the legacy interface, the return value will be either [SQLITE_BUSY],
2852
** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
2853
** With the "v2" interface, any of the other [result codes] or
2854
** [extended result codes] might be returned as well.
2856
** [SQLITE_BUSY] means that the database engine was unable to acquire the
2857
** database locks it needs to do its job. If the statement is a [COMMIT]
2858
** or occurs outside of an explicit transaction, then you can retry the
2859
** statement. If the statement is not a [COMMIT] and occurs within a
2860
** explicit transaction then you should rollback the transaction before
2863
** [SQLITE_DONE] means that the statement has finished executing
2864
** successfully. sqlite3_step() should not be called again on this virtual
2865
** machine without first calling [sqlite3_reset()] to reset the virtual
2866
** machine back to its initial state.
2868
** If the SQL statement being executed returns any data, then [SQLITE_ROW]
2869
** is returned each time a new row of data is ready for processing by the
2870
** caller. The values may be accessed using the [column access functions].
2871
** sqlite3_step() is called again to retrieve the next row of data.
2873
** [SQLITE_ERROR] means that a run-time error (such as a constraint
2874
** violation) has occurred. sqlite3_step() should not be called again on
2875
** the VM. More information may be found by calling [sqlite3_errmsg()].
2876
** With the legacy interface, a more specific error code (for example,
2877
** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
2878
** can be obtained by calling [sqlite3_reset()] on the
2879
** [prepared statement]. In the "v2" interface,
2880
** the more specific error code is returned directly by sqlite3_step().
2882
** [SQLITE_MISUSE] means that the this routine was called inappropriately.
2883
** Perhaps it was called on a [prepared statement] that has
2884
** already been [sqlite3_finalize | finalized] or on one that had
2885
** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could
2886
** be the case that the same database connection is being used by two or
2887
** more threads at the same moment in time.
2889
** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
2890
** API always returns a generic error code, [SQLITE_ERROR], following any
2891
** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call
2892
** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
2893
** specific [error codes] that better describes the error.
2894
** We admit that this is a goofy design. The problem has been fixed
2895
** with the "v2" interface. If you prepare all of your SQL statements
2896
** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead
2897
** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
2898
** then the more specific [error codes] are returned directly
2899
** by sqlite3_step(). The use of the "v2" interface is recommended.
2902
** [H13202] [H15304] [H15306] [H15308] [H15310]
2904
SQLITE_API int sqlite3_step(sqlite3_stmt*);
2907
** CAPI3REF: Number of columns in a result set {H13770} <S10700>
2909
** Returns the number of values in the current row of the result set.
2912
** [H13771] [H13772]
2914
SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
2917
** CAPI3REF: Fundamental Datatypes {H10265} <S10110><S10120>
2918
** KEYWORDS: SQLITE_TEXT
2920
** {H10266} Every value in SQLite has one of five fundamental datatypes:
2923
** <li> 64-bit signed integer
2924
** <li> 64-bit IEEE floating point number
2930
** These constants are codes for each of those types.
2932
** Note that the SQLITE_TEXT constant was also used in SQLite version 2
2933
** for a completely different meaning. Software that links against both
2934
** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
2937
#define SQLITE_INTEGER 1
2938
#define SQLITE_FLOAT 2
2939
#define SQLITE_BLOB 4
2940
#define SQLITE_NULL 5
2944
# define SQLITE_TEXT 3
2946
#define SQLITE3_TEXT 3
2949
** CAPI3REF: Result Values From A Query {H13800} <S10700>
2950
** KEYWORDS: {column access functions}
2952
** These routines form the "result set query" interface.
2954
** These routines return information about a single column of the current
2955
** result row of a query. In every case the first argument is a pointer
2956
** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
2957
** that was returned from [sqlite3_prepare_v2()] or one of its variants)
2958
** and the second argument is the index of the column for which information
2959
** should be returned. The leftmost column of the result set has the index 0.
2960
** The number of columns in the result can be determined using
2961
** [sqlite3_column_count()].
2963
** If the SQL statement does not currently point to a valid row, or if the
2964
** column index is out of range, the result is undefined.
2965
** These routines may only be called when the most recent call to
2966
** [sqlite3_step()] has returned [SQLITE_ROW] and neither
2967
** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
2968
** If any of these routines are called after [sqlite3_reset()] or
2969
** [sqlite3_finalize()] or after [sqlite3_step()] has returned
2970
** something other than [SQLITE_ROW], the results are undefined.
2971
** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
2972
** are called from a different thread while any of these routines
2973
** are pending, then the results are undefined.
2975
** The sqlite3_column_type() routine returns the
2976
** [SQLITE_INTEGER | datatype code] for the initial data type
2977
** of the result column. The returned value is one of [SQLITE_INTEGER],
2978
** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value
2979
** returned by sqlite3_column_type() is only meaningful if no type
2980
** conversions have occurred as described below. After a type conversion,
2981
** the value returned by sqlite3_column_type() is undefined. Future
2982
** versions of SQLite may change the behavior of sqlite3_column_type()
2983
** following a type conversion.
2985
** If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
2986
** routine returns the number of bytes in that BLOB or string.
2987
** If the result is a UTF-16 string, then sqlite3_column_bytes() converts
2988
** the string to UTF-8 and then returns the number of bytes.
2989
** If the result is a numeric value then sqlite3_column_bytes() uses
2990
** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
2991
** the number of bytes in that string.
2992
** The value returned does not include the zero terminator at the end
2993
** of the string. For clarity: the value returned is the number of
2994
** bytes in the string, not the number of characters.
2996
** Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
2997
** even empty strings, are always zero terminated. The return
2998
** value from sqlite3_column_blob() for a zero-length BLOB is an arbitrary
2999
** pointer, possibly even a NULL pointer.
3001
** The sqlite3_column_bytes16() routine is similar to sqlite3_column_bytes()
3002
** but leaves the result in UTF-16 in native byte order instead of UTF-8.
3003
** The zero terminator is not included in this count.
3005
** The object returned by [sqlite3_column_value()] is an
3006
** [unprotected sqlite3_value] object. An unprotected sqlite3_value object
3007
** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()].
3008
** If the [unprotected sqlite3_value] object returned by
3009
** [sqlite3_column_value()] is used in any other way, including calls
3010
** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
3011
** or [sqlite3_value_bytes()], then the behavior is undefined.
3013
** These routines attempt to convert the value where appropriate. For
3014
** example, if the internal representation is FLOAT and a text result
3015
** is requested, [sqlite3_snprintf()] is used internally to perform the
3016
** conversion automatically. The following table details the conversions
3017
** that are applied:
3020
** <table border="1">
3021
** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion
3023
** <tr><td> NULL <td> INTEGER <td> Result is 0
3024
** <tr><td> NULL <td> FLOAT <td> Result is 0.0
3025
** <tr><td> NULL <td> TEXT <td> Result is NULL pointer
3026
** <tr><td> NULL <td> BLOB <td> Result is NULL pointer
3027
** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float
3028
** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer
3029
** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT
3030
** <tr><td> FLOAT <td> INTEGER <td> Convert from float to integer
3031
** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float
3032
** <tr><td> FLOAT <td> BLOB <td> Same as FLOAT->TEXT
3033
** <tr><td> TEXT <td> INTEGER <td> Use atoi()
3034
** <tr><td> TEXT <td> FLOAT <td> Use atof()
3035
** <tr><td> TEXT <td> BLOB <td> No change
3036
** <tr><td> BLOB <td> INTEGER <td> Convert to TEXT then use atoi()
3037
** <tr><td> BLOB <td> FLOAT <td> Convert to TEXT then use atof()
3038
** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed
3042
** The table above makes reference to standard C library functions atoi()
3043
** and atof(). SQLite does not really use these functions. It has its
3044
** own equivalent internal routines. The atoi() and atof() names are
3045
** used in the table for brevity and because they are familiar to most
3048
** Note that when type conversions occur, pointers returned by prior
3049
** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
3050
** sqlite3_column_text16() may be invalidated.
3051
** Type conversions and pointer invalidations might occur
3052
** in the following cases:
3055
** <li> The initial content is a BLOB and sqlite3_column_text() or
3056
** sqlite3_column_text16() is called. A zero-terminator might
3057
** need to be added to the string.</li>
3058
** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
3059
** sqlite3_column_text16() is called. The content must be converted
3061
** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
3062
** sqlite3_column_text() is called. The content must be converted
3066
** Conversions between UTF-16be and UTF-16le are always done in place and do
3067
** not invalidate a prior pointer, though of course the content of the buffer
3068
** that the prior pointer points to will have been modified. Other kinds
3069
** of conversion are done in place when it is possible, but sometimes they
3070
** are not possible and in those cases prior pointers are invalidated.
3072
** The safest and easiest to remember policy is to invoke these routines
3073
** in one of the following ways:
3076
** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
3077
** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
3078
** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
3081
** In other words, you should call sqlite3_column_text(),
3082
** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
3083
** into the desired format, then invoke sqlite3_column_bytes() or
3084
** sqlite3_column_bytes16() to find the size of the result. Do not mix calls
3085
** to sqlite3_column_text() or sqlite3_column_blob() with calls to
3086
** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
3087
** with calls to sqlite3_column_bytes().
3089
** The pointers returned are valid until a type conversion occurs as
3090
** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
3091
** [sqlite3_finalize()] is called. The memory space used to hold strings
3092
** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned
3093
** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
3094
** [sqlite3_free()].
3096
** If a memory allocation error occurs during the evaluation of any
3097
** of these routines, a default value is returned. The default value
3098
** is either the integer 0, the floating point number 0.0, or a NULL
3099
** pointer. Subsequent calls to [sqlite3_errcode()] will return
3103
** [H13803] [H13806] [H13809] [H13812] [H13815] [H13818] [H13821] [H13824]
3104
** [H13827] [H13830]
3106
SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
3107
SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
3108
SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
3109
SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol);
3110
SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol);
3111
SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
3112
SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
3113
SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
3114
SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol);
3115
SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
3118
** CAPI3REF: Destroy A Prepared Statement Object {H13300} <S70300><S30100>
3120
** The sqlite3_finalize() function is called to delete a [prepared statement].
3121
** If the statement was executed successfully or not executed at all, then
3122
** SQLITE_OK is returned. If execution of the statement failed then an
3123
** [error code] or [extended error code] is returned.
3125
** This routine can be called at any point during the execution of the
3126
** [prepared statement]. If the virtual machine has not
3127
** completed execution when this routine is called, that is like
3128
** encountering an error or an [sqlite3_interrupt | interrupt].
3129
** Incomplete updates may be rolled back and transactions canceled,
3130
** depending on the circumstances, and the
3131
** [error code] returned will be [SQLITE_ABORT].
3134
** [H11302] [H11304]
3136
SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt);
3139
** CAPI3REF: Reset A Prepared Statement Object {H13330} <S70300>
3141
** The sqlite3_reset() function is called to reset a [prepared statement]
3142
** object back to its initial state, ready to be re-executed.
3143
** Any SQL statement variables that had values bound to them using
3144
** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
3145
** Use [sqlite3_clear_bindings()] to reset the bindings.
3147
** {H11332} The [sqlite3_reset(S)] interface resets the [prepared statement] S
3148
** back to the beginning of its program.
3150
** {H11334} If the most recent call to [sqlite3_step(S)] for the
3151
** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
3152
** or if [sqlite3_step(S)] has never before been called on S,
3153
** then [sqlite3_reset(S)] returns [SQLITE_OK].
3155
** {H11336} If the most recent call to [sqlite3_step(S)] for the
3156
** [prepared statement] S indicated an error, then
3157
** [sqlite3_reset(S)] returns an appropriate [error code].
3159
** {H11338} The [sqlite3_reset(S)] interface does not change the values
3160
** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
3162
SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt);
3165
** CAPI3REF: Create Or Redefine SQL Functions {H16100} <S20200>
3166
** KEYWORDS: {function creation routines}
3167
** KEYWORDS: {application-defined SQL function}
3168
** KEYWORDS: {application-defined SQL functions}
3170
** These two functions (collectively known as "function creation routines")
3171
** are used to add SQL functions or aggregates or to redefine the behavior
3172
** of existing SQL functions or aggregates. The only difference between the
3173
** two is that the second parameter, the name of the (scalar) function or
3174
** aggregate, is encoded in UTF-8 for sqlite3_create_function() and UTF-16
3175
** for sqlite3_create_function16().
3177
** The first parameter is the [database connection] to which the SQL
3178
** function is to be added. If a single program uses more than one database
3179
** connection internally, then SQL functions must be added individually to
3180
** each database connection.
3182
** The second parameter is the name of the SQL function to be created or
3183
** redefined. The length of the name is limited to 255 bytes, exclusive of
3184
** the zero-terminator. Note that the name length limit is in bytes, not
3185
** characters. Any attempt to create a function with a longer name
3186
** will result in [SQLITE_ERROR] being returned.
3188
** The third parameter (nArg)
3189
** is the number of arguments that the SQL function or
3190
** aggregate takes. If this parameter is -1, then the SQL function or
3191
** aggregate may take any number of arguments between 0 and the limit
3192
** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third
3193
** parameter is less than -1 or greater than 127 then the behavior is
3196
** The fourth parameter, eTextRep, specifies what
3197
** [SQLITE_UTF8 | text encoding] this SQL function prefers for
3198
** its parameters. Any SQL function implementation should be able to work
3199
** work with UTF-8, UTF-16le, or UTF-16be. But some implementations may be
3200
** more efficient with one encoding than another. An application may
3201
** invoke sqlite3_create_function() or sqlite3_create_function16() multiple
3202
** times with the same function but with different values of eTextRep.
3203
** When multiple implementations of the same function are available, SQLite
3204
** will pick the one that involves the least amount of data conversion.
3205
** If there is only a single implementation which does not care what text
3206
** encoding is used, then the fourth argument should be [SQLITE_ANY].
3208
** The fifth parameter is an arbitrary pointer. The implementation of the
3209
** function can gain access to this pointer using [sqlite3_user_data()].
3211
** The seventh, eighth and ninth parameters, xFunc, xStep and xFinal, are
3212
** pointers to C-language functions that implement the SQL function or
3213
** aggregate. A scalar SQL function requires an implementation of the xFunc
3214
** callback only, NULL pointers should be passed as the xStep and xFinal
3215
** parameters. An aggregate SQL function requires an implementation of xStep
3216
** and xFinal and NULL should be passed for xFunc. To delete an existing
3217
** SQL function or aggregate, pass NULL for all three function callbacks.
3219
** It is permitted to register multiple implementations of the same
3220
** functions with the same name but with either differing numbers of
3221
** arguments or differing preferred text encodings. SQLite will use
3222
** the implementation that most closely matches the way in which the
3223
** SQL function is used. A function implementation with a non-negative
3224
** nArg parameter is a better match than a function implementation with
3225
** a negative nArg. A function where the preferred text encoding
3226
** matches the database encoding is a better
3227
** match than a function where the encoding is different.
3228
** A function where the encoding difference is between UTF16le and UTF16be
3229
** is a closer match than a function where the encoding difference is
3230
** between UTF8 and UTF16.
3232
** Built-in functions may be overloaded by new application-defined functions.
3233
** The first application-defined function with a given name overrides all
3234
** built-in functions in the same [database connection] with the same name.
3235
** Subsequent application-defined functions of the same name only override
3236
** prior application-defined functions that are an exact match for the
3237
** number of parameters and preferred encoding.
3239
** An application-defined function is permitted to call other
3240
** SQLite interfaces. However, such calls must not
3241
** close the database connection nor finalize or reset the prepared
3242
** statement in which the function is running.
3245
** [H16103] [H16106] [H16109] [H16112] [H16118] [H16121] [H16127]
3246
** [H16130] [H16133] [H16136] [H16139] [H16142]
3248
SQLITE_API int sqlite3_create_function(
3250
const char *zFunctionName,
3254
void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
3255
void (*xStep)(sqlite3_context*,int,sqlite3_value**),
3256
void (*xFinal)(sqlite3_context*)
3258
SQLITE_API int sqlite3_create_function16(
3260
const void *zFunctionName,
3264
void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
3265
void (*xStep)(sqlite3_context*,int,sqlite3_value**),
3266
void (*xFinal)(sqlite3_context*)
3270
** CAPI3REF: Text Encodings {H10267} <S50200> <H16100>
3272
** These constant define integer codes that represent the various
3273
** text encodings supported by SQLite.
3275
#define SQLITE_UTF8 1
3276
#define SQLITE_UTF16LE 2
3277
#define SQLITE_UTF16BE 3
3278
#define SQLITE_UTF16 4 /* Use native byte order */
3279
#define SQLITE_ANY 5 /* sqlite3_create_function only */
3280
#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */
3283
** CAPI3REF: Deprecated Functions
3286
** These functions are [deprecated]. In order to maintain
3287
** backwards compatibility with older code, these functions continue
3288
** to be supported. However, new applications should avoid
3289
** the use of these functions. To help encourage people to avoid
3290
** using these functions, we are not going to tell you what they do.
3292
#ifndef SQLITE_OMIT_DEPRECATED
3293
SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
3294
SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
3295
SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
3296
SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void);
3297
SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
3298
SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64);
3302
** CAPI3REF: Obtaining SQL Function Parameter Values {H15100} <S20200>
3304
** The C-language implementation of SQL functions and aggregates uses
3305
** this set of interface routines to access the parameter values on
3306
** the function or aggregate.
3308
** The xFunc (for scalar functions) or xStep (for aggregates) parameters
3309
** to [sqlite3_create_function()] and [sqlite3_create_function16()]
3310
** define callbacks that implement the SQL functions and aggregates.
3311
** The 4th parameter to these callbacks is an array of pointers to
3312
** [protected sqlite3_value] objects. There is one [sqlite3_value] object for
3313
** each parameter to the SQL function. These routines are used to
3314
** extract values from the [sqlite3_value] objects.
3316
** These routines work only with [protected sqlite3_value] objects.
3317
** Any attempt to use these routines on an [unprotected sqlite3_value]
3318
** object results in undefined behavior.
3320
** These routines work just like the corresponding [column access functions]
3321
** except that these routines take a single [protected sqlite3_value] object
3322
** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
3324
** The sqlite3_value_text16() interface extracts a UTF-16 string
3325
** in the native byte-order of the host machine. The
3326
** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
3327
** extract UTF-16 strings as big-endian and little-endian respectively.
3329
** The sqlite3_value_numeric_type() interface attempts to apply
3330
** numeric affinity to the value. This means that an attempt is
3331
** made to convert the value to an integer or floating point. If
3332
** such a conversion is possible without loss of information (in other
3333
** words, if the value is a string that looks like a number)
3334
** then the conversion is performed. Otherwise no conversion occurs.
3335
** The [SQLITE_INTEGER | datatype] after conversion is returned.
3337
** Please pay particular attention to the fact that the pointer returned
3338
** from [sqlite3_value_blob()], [sqlite3_value_text()], or
3339
** [sqlite3_value_text16()] can be invalidated by a subsequent call to
3340
** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
3341
** or [sqlite3_value_text16()].
3343
** These routines must be called from the same thread as
3344
** the SQL function that supplied the [sqlite3_value*] parameters.
3347
** [H15103] [H15106] [H15109] [H15112] [H15115] [H15118] [H15121] [H15124]
3348
** [H15127] [H15130] [H15133] [H15136]
3350
SQLITE_API const void *sqlite3_value_blob(sqlite3_value*);
3351
SQLITE_API int sqlite3_value_bytes(sqlite3_value*);
3352
SQLITE_API int sqlite3_value_bytes16(sqlite3_value*);
3353
SQLITE_API double sqlite3_value_double(sqlite3_value*);
3354
SQLITE_API int sqlite3_value_int(sqlite3_value*);
3355
SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
3356
SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*);
3357
SQLITE_API const void *sqlite3_value_text16(sqlite3_value*);
3358
SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*);
3359
SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*);
3360
SQLITE_API int sqlite3_value_type(sqlite3_value*);
3361
SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*);
3364
** CAPI3REF: Obtain Aggregate Function Context {H16210} <S20200>
3366
** The implementation of aggregate SQL functions use this routine to allocate
3367
** a structure for storing their state.
3369
** The first time the sqlite3_aggregate_context() routine is called for a
3370
** particular aggregate, SQLite allocates nBytes of memory, zeroes out that
3371
** memory, and returns a pointer to it. On second and subsequent calls to
3372
** sqlite3_aggregate_context() for the same aggregate function index,
3373
** the same buffer is returned. The implementation of the aggregate can use
3374
** the returned buffer to accumulate data.
3376
** SQLite automatically frees the allocated buffer when the aggregate
3379
** The first parameter should be a copy of the
3380
** [sqlite3_context | SQL function context] that is the first parameter
3381
** to the callback routine that implements the aggregate function.
3383
** This routine must be called from the same thread in which
3384
** the aggregate SQL function is running.
3387
** [H16211] [H16213] [H16215] [H16217]
3389
SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
3392
** CAPI3REF: User Data For Functions {H16240} <S20200>
3394
** The sqlite3_user_data() interface returns a copy of
3395
** the pointer that was the pUserData parameter (the 5th parameter)
3396
** of the [sqlite3_create_function()]
3397
** and [sqlite3_create_function16()] routines that originally
3398
** registered the application defined function. {END}
3400
** This routine must be called from the same thread in which
3401
** the application-defined function is running.
3406
SQLITE_API void *sqlite3_user_data(sqlite3_context*);
3409
** CAPI3REF: Database Connection For Functions {H16250} <S60600><S20200>
3411
** The sqlite3_context_db_handle() interface returns a copy of
3412
** the pointer to the [database connection] (the 1st parameter)
3413
** of the [sqlite3_create_function()]
3414
** and [sqlite3_create_function16()] routines that originally
3415
** registered the application defined function.
3420
SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
3423
** CAPI3REF: Function Auxiliary Data {H16270} <S20200>
3425
** The following two functions may be used by scalar SQL functions to
3426
** associate metadata with argument values. If the same value is passed to
3427
** multiple invocations of the same SQL function during query execution, under
3428
** some circumstances the associated metadata may be preserved. This may
3429
** be used, for example, to add a regular-expression matching scalar
3430
** function. The compiled version of the regular expression is stored as
3431
** metadata associated with the SQL value passed as the regular expression
3432
** pattern. The compiled regular expression can be reused on multiple
3433
** invocations of the same function so that the original pattern string
3434
** does not need to be recompiled on each invocation.
3436
** The sqlite3_get_auxdata() interface returns a pointer to the metadata
3437
** associated by the sqlite3_set_auxdata() function with the Nth argument
3438
** value to the application-defined function. If no metadata has been ever
3439
** been set for the Nth argument of the function, or if the corresponding
3440
** function parameter has changed since the meta-data was set,
3441
** then sqlite3_get_auxdata() returns a NULL pointer.
3443
** The sqlite3_set_auxdata() interface saves the metadata
3444
** pointed to by its 3rd parameter as the metadata for the N-th
3445
** argument of the application-defined function. Subsequent
3446
** calls to sqlite3_get_auxdata() might return this data, if it has
3447
** not been destroyed.
3448
** If it is not NULL, SQLite will invoke the destructor
3449
** function given by the 4th parameter to sqlite3_set_auxdata() on
3450
** the metadata when the corresponding function parameter changes
3451
** or when the SQL statement completes, whichever comes first.
3453
** SQLite is free to call the destructor and drop metadata on any
3454
** parameter of any function at any time. The only guarantee is that
3455
** the destructor will be called before the metadata is dropped.
3457
** In practice, metadata is preserved between function calls for
3458
** expressions that are constant at compile time. This includes literal
3459
** values and SQL variables.
3461
** These routines must be called from the same thread in which
3462
** the SQL function is running.
3465
** [H16272] [H16274] [H16276] [H16277] [H16278] [H16279]
3467
SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N);
3468
SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
3472
** CAPI3REF: Constants Defining Special Destructor Behavior {H10280} <S30100>
3474
** These are special values for the destructor that is passed in as the
3475
** final argument to routines like [sqlite3_result_blob()]. If the destructor
3476
** argument is SQLITE_STATIC, it means that the content pointer is constant
3477
** and will never change. It does not need to be destroyed. The
3478
** SQLITE_TRANSIENT value means that the content will likely change in
3479
** the near future and that SQLite should make its own private copy of
3480
** the content before returning.
3482
** The typedef is necessary to work around problems in certain
3483
** C++ compilers. See ticket #2191.
3485
typedef void (*sqlite3_destructor_type)(void*);
3486
#define SQLITE_STATIC ((sqlite3_destructor_type)0)
3487
#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1)
3490
** CAPI3REF: Setting The Result Of An SQL Function {H16400} <S20200>
3492
** These routines are used by the xFunc or xFinal callbacks that
3493
** implement SQL functions and aggregates. See
3494
** [sqlite3_create_function()] and [sqlite3_create_function16()]
3495
** for additional information.
3497
** These functions work very much like the [parameter binding] family of
3498
** functions used to bind values to host parameters in prepared statements.
3499
** Refer to the [SQL parameter] documentation for additional information.
3501
** The sqlite3_result_blob() interface sets the result from
3502
** an application-defined function to be the BLOB whose content is pointed
3503
** to by the second parameter and which is N bytes long where N is the
3506
** The sqlite3_result_zeroblob() interfaces set the result of
3507
** the application-defined function to be a BLOB containing all zero
3508
** bytes and N bytes in size, where N is the value of the 2nd parameter.
3510
** The sqlite3_result_double() interface sets the result from
3511
** an application-defined function to be a floating point value specified
3512
** by its 2nd argument.
3514
** The sqlite3_result_error() and sqlite3_result_error16() functions
3515
** cause the implemented SQL function to throw an exception.
3516
** SQLite uses the string pointed to by the
3517
** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
3518
** as the text of an error message. SQLite interprets the error
3519
** message string from sqlite3_result_error() as UTF-8. SQLite
3520
** interprets the string from sqlite3_result_error16() as UTF-16 in native
3521
** byte order. If the third parameter to sqlite3_result_error()
3522
** or sqlite3_result_error16() is negative then SQLite takes as the error
3523
** message all text up through the first zero character.
3524
** If the third parameter to sqlite3_result_error() or
3525
** sqlite3_result_error16() is non-negative then SQLite takes that many
3526
** bytes (not characters) from the 2nd parameter as the error message.
3527
** The sqlite3_result_error() and sqlite3_result_error16()
3528
** routines make a private copy of the error message text before
3529
** they return. Hence, the calling function can deallocate or
3530
** modify the text after they return without harm.
3531
** The sqlite3_result_error_code() function changes the error code
3532
** returned by SQLite as a result of an error in a function. By default,
3533
** the error code is SQLITE_ERROR. A subsequent call to sqlite3_result_error()
3534
** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
3536
** The sqlite3_result_toobig() interface causes SQLite to throw an error
3537
** indicating that a string or BLOB is to long to represent.
3539
** The sqlite3_result_nomem() interface causes SQLite to throw an error
3540
** indicating that a memory allocation failed.
3542
** The sqlite3_result_int() interface sets the return value
3543
** of the application-defined function to be the 32-bit signed integer
3544
** value given in the 2nd argument.
3545
** The sqlite3_result_int64() interface sets the return value
3546
** of the application-defined function to be the 64-bit signed integer
3547
** value given in the 2nd argument.
3549
** The sqlite3_result_null() interface sets the return value
3550
** of the application-defined function to be NULL.
3552
** The sqlite3_result_text(), sqlite3_result_text16(),
3553
** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
3554
** set the return value of the application-defined function to be
3555
** a text string which is represented as UTF-8, UTF-16 native byte order,
3556
** UTF-16 little endian, or UTF-16 big endian, respectively.
3557
** SQLite takes the text result from the application from
3558
** the 2nd parameter of the sqlite3_result_text* interfaces.
3559
** If the 3rd parameter to the sqlite3_result_text* interfaces
3560
** is negative, then SQLite takes result text from the 2nd parameter
3561
** through the first zero character.
3562
** If the 3rd parameter to the sqlite3_result_text* interfaces
3563
** is non-negative, then as many bytes (not characters) of the text
3564
** pointed to by the 2nd parameter are taken as the application-defined
3566
** If the 4th parameter to the sqlite3_result_text* interfaces
3567
** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
3568
** function as the destructor on the text or BLOB result when it has
3569
** finished using that result.
3570
** If the 4th parameter to the sqlite3_result_text* interfaces or to
3571
** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
3572
** assumes that the text or BLOB result is in constant space and does not
3573
** copy the content of the parameter nor call a destructor on the content
3574
** when it has finished using that result.
3575
** If the 4th parameter to the sqlite3_result_text* interfaces
3576
** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
3577
** then SQLite makes a copy of the result into space obtained from
3578
** from [sqlite3_malloc()] before it returns.
3580
** The sqlite3_result_value() interface sets the result of
3581
** the application-defined function to be a copy the
3582
** [unprotected sqlite3_value] object specified by the 2nd parameter. The
3583
** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
3584
** so that the [sqlite3_value] specified in the parameter may change or
3585
** be deallocated after sqlite3_result_value() returns without harm.
3586
** A [protected sqlite3_value] object may always be used where an
3587
** [unprotected sqlite3_value] object is required, so either
3588
** kind of [sqlite3_value] object can be used with this interface.
3590
** If these routines are called from within the different thread
3591
** than the one containing the application-defined function that received
3592
** the [sqlite3_context] pointer, the results are undefined.
3595
** [H16403] [H16406] [H16409] [H16412] [H16415] [H16418] [H16421] [H16424]
3596
** [H16427] [H16430] [H16433] [H16436] [H16439] [H16442] [H16445] [H16448]
3597
** [H16451] [H16454] [H16457] [H16460] [H16463]
3599
SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
3600
SQLITE_API void sqlite3_result_double(sqlite3_context*, double);
3601
SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int);
3602
SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int);
3603
SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*);
3604
SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*);
3605
SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int);
3606
SQLITE_API void sqlite3_result_int(sqlite3_context*, int);
3607
SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
3608
SQLITE_API void sqlite3_result_null(sqlite3_context*);
3609
SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
3610
SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
3611
SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
3612
SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
3613
SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
3614
SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n);
3617
** CAPI3REF: Define New Collating Sequences {H16600} <S20300>
3619
** These functions are used to add new collation sequences to the
3620
** [database connection] specified as the first argument.
3622
** The name of the new collation sequence is specified as a UTF-8 string
3623
** for sqlite3_create_collation() and sqlite3_create_collation_v2()
3624
** and a UTF-16 string for sqlite3_create_collation16(). In all cases
3625
** the name is passed as the second function argument.
3627
** The third argument may be one of the constants [SQLITE_UTF8],
3628
** [SQLITE_UTF16LE], or [SQLITE_UTF16BE], indicating that the user-supplied
3629
** routine expects to be passed pointers to strings encoded using UTF-8,
3630
** UTF-16 little-endian, or UTF-16 big-endian, respectively. The
3631
** third argument might also be [SQLITE_UTF16] to indicate that the routine
3632
** expects pointers to be UTF-16 strings in the native byte order, or the
3633
** argument can be [SQLITE_UTF16_ALIGNED] if the
3634
** the routine expects pointers to 16-bit word aligned strings
3635
** of UTF-16 in the native byte order.
3637
** A pointer to the user supplied routine must be passed as the fifth
3638
** argument. If it is NULL, this is the same as deleting the collation
3639
** sequence (so that SQLite cannot call it anymore).
3640
** Each time the application supplied function is invoked, it is passed
3641
** as its first parameter a copy of the void* passed as the fourth argument
3642
** to sqlite3_create_collation() or sqlite3_create_collation16().
3644
** The remaining arguments to the application-supplied routine are two strings,
3645
** each represented by a (length, data) pair and encoded in the encoding
3646
** that was passed as the third argument when the collation sequence was
3647
** registered. {END} The application defined collation routine should
3648
** return negative, zero or positive if the first string is less than,
3649
** equal to, or greater than the second string. i.e. (STRING1 - STRING2).
3651
** The sqlite3_create_collation_v2() works like sqlite3_create_collation()
3652
** except that it takes an extra argument which is a destructor for
3653
** the collation. The destructor is called when the collation is
3654
** destroyed and is passed a copy of the fourth parameter void* pointer
3655
** of the sqlite3_create_collation_v2().
3656
** Collations are destroyed when they are overridden by later calls to the
3657
** collation creation functions or when the [database connection] is closed
3658
** using [sqlite3_close()].
3660
** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
3663
** [H16603] [H16604] [H16606] [H16609] [H16612] [H16615] [H16618] [H16621]
3664
** [H16624] [H16627] [H16630]
3666
SQLITE_API int sqlite3_create_collation(
3671
int(*xCompare)(void*,int,const void*,int,const void*)
3673
SQLITE_API int sqlite3_create_collation_v2(
3678
int(*xCompare)(void*,int,const void*,int,const void*),
3679
void(*xDestroy)(void*)
3681
SQLITE_API int sqlite3_create_collation16(
3686
int(*xCompare)(void*,int,const void*,int,const void*)
3690
** CAPI3REF: Collation Needed Callbacks {H16700} <S20300>
3692
** To avoid having to register all collation sequences before a database
3693
** can be used, a single callback function may be registered with the
3694
** [database connection] to be called whenever an undefined collation
3695
** sequence is required.
3697
** If the function is registered using the sqlite3_collation_needed() API,
3698
** then it is passed the names of undefined collation sequences as strings
3699
** encoded in UTF-8. {H16703} If sqlite3_collation_needed16() is used,
3700
** the names are passed as UTF-16 in machine native byte order.
3701
** A call to either function replaces any existing callback.
3703
** When the callback is invoked, the first argument passed is a copy
3704
** of the second argument to sqlite3_collation_needed() or
3705
** sqlite3_collation_needed16(). The second argument is the database
3706
** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
3707
** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
3708
** sequence function required. The fourth parameter is the name of the
3709
** required collation sequence.
3711
** The callback function should register the desired collation using
3712
** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
3713
** [sqlite3_create_collation_v2()].
3716
** [H16702] [H16704] [H16706]
3718
SQLITE_API int sqlite3_collation_needed(
3721
void(*)(void*,sqlite3*,int eTextRep,const char*)
3723
SQLITE_API int sqlite3_collation_needed16(
3726
void(*)(void*,sqlite3*,int eTextRep,const void*)
3730
** Specify the key for an encrypted database. This routine should be
3731
** called right after sqlite3_open().
3733
** The code to implement this API is not available in the public release
3736
SQLITE_API int sqlite3_key(
3737
sqlite3 *db, /* Database to be rekeyed */
3738
const void *pKey, int nKey /* The key */
3742
** Change the key on an open database. If the current database is not
3743
** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the
3744
** database is decrypted.
3746
** The code to implement this API is not available in the public release
3749
SQLITE_API int sqlite3_rekey(
3750
sqlite3 *db, /* Database to be rekeyed */
3751
const void *pKey, int nKey /* The new key */
3755
** CAPI3REF: Suspend Execution For A Short Time {H10530} <S40410>
3757
** The sqlite3_sleep() function causes the current thread to suspend execution
3758
** for at least a number of milliseconds specified in its parameter.
3760
** If the operating system does not support sleep requests with
3761
** millisecond time resolution, then the time will be rounded up to
3762
** the nearest second. The number of milliseconds of sleep actually
3763
** requested from the operating system is returned.
3765
** SQLite implements this interface by calling the xSleep()
3766
** method of the default [sqlite3_vfs] object.
3768
** Requirements: [H10533] [H10536]
3770
SQLITE_API int sqlite3_sleep(int);
3773
** CAPI3REF: Name Of The Folder Holding Temporary Files {H10310} <S20000>
3775
** If this global variable is made to point to a string which is
3776
** the name of a folder (a.k.a. directory), then all temporary files
3777
** created by SQLite will be placed in that directory. If this variable
3778
** is a NULL pointer, then SQLite performs a search for an appropriate
3779
** temporary file directory.
3781
** It is not safe to read or modify this variable in more than one
3782
** thread at a time. It is not safe to read or modify this variable
3783
** if a [database connection] is being used at the same time in a separate
3785
** It is intended that this variable be set once
3786
** as part of process initialization and before any SQLite interface
3787
** routines have been called and that this variable remain unchanged
3790
** The [temp_store_directory pragma] may modify this variable and cause
3791
** it to point to memory obtained from [sqlite3_malloc]. Furthermore,
3792
** the [temp_store_directory pragma] always assumes that any string
3793
** that this variable points to is held in memory obtained from
3794
** [sqlite3_malloc] and the pragma may attempt to free that memory
3795
** using [sqlite3_free].
3796
** Hence, if this variable is modified directly, either it should be
3797
** made NULL or made to point to memory obtained from [sqlite3_malloc]
3798
** or else the use of the [temp_store_directory pragma] should be avoided.
3800
SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory;
3803
** CAPI3REF: Test For Auto-Commit Mode {H12930} <S60200>
3804
** KEYWORDS: {autocommit mode}
3806
** The sqlite3_get_autocommit() interface returns non-zero or
3807
** zero if the given database connection is or is not in autocommit mode,
3808
** respectively. Autocommit mode is on by default.
3809
** Autocommit mode is disabled by a [BEGIN] statement.
3810
** Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
3812
** If certain kinds of errors occur on a statement within a multi-statement
3813
** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
3814
** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
3815
** transaction might be rolled back automatically. The only way to
3816
** find out whether SQLite automatically rolled back the transaction after
3817
** an error is to use this function.
3819
** If another thread changes the autocommit status of the database
3820
** connection while this routine is running, then the return value
3823
** Requirements: [H12931] [H12932] [H12933] [H12934]
3825
SQLITE_API int sqlite3_get_autocommit(sqlite3*);
3828
** CAPI3REF: Find The Database Handle Of A Prepared Statement {H13120} <S60600>
3830
** The sqlite3_db_handle interface returns the [database connection] handle
3831
** to which a [prepared statement] belongs. The [database connection]
3832
** returned by sqlite3_db_handle is the same [database connection] that was the first argument
3833
** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
3834
** create the statement in the first place.
3836
** Requirements: [H13123]
3838
SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
3841
** CAPI3REF: Find the next prepared statement {H13140} <S60600>
3843
** This interface returns a pointer to the next [prepared statement] after
3844
** pStmt associated with the [database connection] pDb. If pStmt is NULL
3845
** then this interface returns a pointer to the first prepared statement
3846
** associated with the database connection pDb. If no prepared statement
3847
** satisfies the conditions of this routine, it returns NULL.
3849
** The [database connection] pointer D in a call to
3850
** [sqlite3_next_stmt(D,S)] must refer to an open database
3851
** connection and in particular must not be a NULL pointer.
3853
** Requirements: [H13143] [H13146] [H13149] [H13152]
3855
SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
3858
** CAPI3REF: Commit And Rollback Notification Callbacks {H12950} <S60400>
3860
** The sqlite3_commit_hook() interface registers a callback
3861
** function to be invoked whenever a transaction is [COMMIT | committed].
3862
** Any callback set by a previous call to sqlite3_commit_hook()
3863
** for the same database connection is overridden.
3864
** The sqlite3_rollback_hook() interface registers a callback
3865
** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
3866
** Any callback set by a previous call to sqlite3_commit_hook()
3867
** for the same database connection is overridden.
3868
** The pArg argument is passed through to the callback.
3869
** If the callback on a commit hook function returns non-zero,
3870
** then the commit is converted into a rollback.
3872
** If another function was previously registered, its
3873
** pArg value is returned. Otherwise NULL is returned.
3875
** The callback implementation must not do anything that will modify
3876
** the database connection that invoked the callback. Any actions
3877
** to modify the database connection must be deferred until after the
3878
** completion of the [sqlite3_step()] call that triggered the commit
3879
** or rollback hook in the first place.
3880
** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
3881
** database connections for the meaning of "modify" in this paragraph.
3883
** Registering a NULL function disables the callback.
3885
** When the commit hook callback routine returns zero, the [COMMIT]
3886
** operation is allowed to continue normally. If the commit hook
3887
** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
3888
** The rollback hook is invoked on a rollback that results from a commit
3889
** hook returning non-zero, just as it would be with any other rollback.
3891
** For the purposes of this API, a transaction is said to have been
3892
** rolled back if an explicit "ROLLBACK" statement is executed, or
3893
** an error or constraint causes an implicit rollback to occur.
3894
** The rollback callback is not invoked if a transaction is
3895
** automatically rolled back because the database connection is closed.
3896
** The rollback callback is not invoked if a transaction is
3897
** rolled back because a commit callback returned non-zero.
3898
** <todo> Check on this </todo>
3900
** See also the [sqlite3_update_hook()] interface.
3903
** [H12951] [H12952] [H12953] [H12954] [H12955]
3904
** [H12961] [H12962] [H12963] [H12964]
3906
SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
3907
SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
3910
** CAPI3REF: Data Change Notification Callbacks {H12970} <S60400>
3912
** The sqlite3_update_hook() interface registers a callback function
3913
** with the [database connection] identified by the first argument
3914
** to be invoked whenever a row is updated, inserted or deleted.
3915
** Any callback set by a previous call to this function
3916
** for the same database connection is overridden.
3918
** The second argument is a pointer to the function to invoke when a
3919
** row is updated, inserted or deleted.
3920
** The first argument to the callback is a copy of the third argument
3921
** to sqlite3_update_hook().
3922
** The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
3923
** or [SQLITE_UPDATE], depending on the operation that caused the callback
3925
** The third and fourth arguments to the callback contain pointers to the
3926
** database and table name containing the affected row.
3927
** The final callback parameter is the [rowid] of the row.
3928
** In the case of an update, this is the [rowid] after the update takes place.
3930
** The update hook is not invoked when internal system tables are
3931
** modified (i.e. sqlite_master and sqlite_sequence).
3933
** In the current implementation, the update hook
3934
** is not invoked when duplication rows are deleted because of an
3935
** [ON CONFLICT | ON CONFLICT REPLACE] clause. Nor is the update hook
3936
** invoked when rows are deleted using the [truncate optimization].
3937
** The exceptions defined in this paragraph might change in a future
3938
** release of SQLite.
3940
** The update hook implementation must not do anything that will modify
3941
** the database connection that invoked the update hook. Any actions
3942
** to modify the database connection must be deferred until after the
3943
** completion of the [sqlite3_step()] call that triggered the update hook.
3944
** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
3945
** database connections for the meaning of "modify" in this paragraph.
3947
** If another function was previously registered, its pArg value
3948
** is returned. Otherwise NULL is returned.
3950
** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()]
3954
** [H12971] [H12973] [H12975] [H12977] [H12979] [H12981] [H12983] [H12986]
3956
SQLITE_API void *sqlite3_update_hook(
3958
void(*)(void *,int ,char const *,char const *,sqlite3_int64),
3963
** CAPI3REF: Enable Or Disable Shared Pager Cache {H10330} <S30900>
3964
** KEYWORDS: {shared cache}
3966
** This routine enables or disables the sharing of the database cache
3967
** and schema data structures between [database connection | connections]
3968
** to the same database. Sharing is enabled if the argument is true
3969
** and disabled if the argument is false.
3971
** Cache sharing is enabled and disabled for an entire process.
3972
** This is a change as of SQLite version 3.5.0. In prior versions of SQLite,
3973
** sharing was enabled or disabled for each thread separately.
3975
** The cache sharing mode set by this interface effects all subsequent
3976
** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
3977
** Existing database connections continue use the sharing mode
3978
** that was in effect at the time they were opened.
3980
** Virtual tables cannot be used with a shared cache. When shared
3981
** cache is enabled, the [sqlite3_create_module()] API used to register
3982
** virtual tables will always return an error.
3984
** This routine returns [SQLITE_OK] if shared cache was enabled or disabled
3985
** successfully. An [error code] is returned otherwise.
3987
** Shared cache is disabled by default. But this might change in
3988
** future releases of SQLite. Applications that care about shared
3989
** cache setting should set it explicitly.
3991
** See Also: [SQLite Shared-Cache Mode]
3993
** Requirements: [H10331] [H10336] [H10337] [H10339]
3995
SQLITE_API int sqlite3_enable_shared_cache(int);
3998
** CAPI3REF: Attempt To Free Heap Memory {H17340} <S30220>
4000
** The sqlite3_release_memory() interface attempts to free N bytes
4001
** of heap memory by deallocating non-essential memory allocations
4002
** held by the database library. {END} Memory used to cache database
4003
** pages to improve performance is an example of non-essential memory.
4004
** sqlite3_release_memory() returns the number of bytes actually freed,
4005
** which might be more or less than the amount requested.
4007
** Requirements: [H17341] [H17342]
4009
SQLITE_API int sqlite3_release_memory(int);
4012
** CAPI3REF: Impose A Limit On Heap Size {H17350} <S30220>
4014
** The sqlite3_soft_heap_limit() interface places a "soft" limit
4015
** on the amount of heap memory that may be allocated by SQLite.
4016
** If an internal allocation is requested that would exceed the
4017
** soft heap limit, [sqlite3_release_memory()] is invoked one or
4018
** more times to free up some space before the allocation is performed.
4020
** The limit is called "soft", because if [sqlite3_release_memory()]
4021
** cannot free sufficient memory to prevent the limit from being exceeded,
4022
** the memory is allocated anyway and the current operation proceeds.
4024
** A negative or zero value for N means that there is no soft heap limit and
4025
** [sqlite3_release_memory()] will only be called when memory is exhausted.
4026
** The default value for the soft heap limit is zero.
4028
** SQLite makes a best effort to honor the soft heap limit.
4029
** But if the soft heap limit cannot be honored, execution will
4030
** continue without error or notification. This is why the limit is
4031
** called a "soft" limit. It is advisory only.
4033
** Prior to SQLite version 3.5.0, this routine only constrained the memory
4034
** allocated by a single thread - the same thread in which this routine
4035
** runs. Beginning with SQLite version 3.5.0, the soft heap limit is
4036
** applied to all threads. The value specified for the soft heap limit
4037
** is an upper bound on the total memory allocation for all threads. In
4038
** version 3.5.0 there is no mechanism for limiting the heap usage for
4039
** individual threads.
4042
** [H16351] [H16352] [H16353] [H16354] [H16355] [H16358]
4044
SQLITE_API void sqlite3_soft_heap_limit(int);
4047
** CAPI3REF: Extract Metadata About A Column Of A Table {H12850} <S60300>
4049
** This routine returns metadata about a specific column of a specific
4050
** database table accessible using the [database connection] handle
4051
** passed as the first function argument.
4053
** The column is identified by the second, third and fourth parameters to
4054
** this function. The second parameter is either the name of the database
4055
** (i.e. "main", "temp" or an attached database) containing the specified
4056
** table or NULL. If it is NULL, then all attached databases are searched
4057
** for the table using the same algorithm used by the database engine to
4058
** resolve unqualified table references.
4060
** The third and fourth parameters to this function are the table and column
4061
** name of the desired column, respectively. Neither of these parameters
4064
** Metadata is returned by writing to the memory locations passed as the 5th
4065
** and subsequent parameters to this function. Any of these arguments may be
4066
** NULL, in which case the corresponding element of metadata is omitted.
4069
** <table border="1">
4070
** <tr><th> Parameter <th> Output<br>Type <th> Description
4072
** <tr><td> 5th <td> const char* <td> Data type
4073
** <tr><td> 6th <td> const char* <td> Name of default collation sequence
4074
** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint
4075
** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY
4076
** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT]
4080
** The memory pointed to by the character pointers returned for the
4081
** declaration type and collation sequence is valid only until the next
4082
** call to any SQLite API function.
4084
** If the specified table is actually a view, an [error code] is returned.
4086
** If the specified column is "rowid", "oid" or "_rowid_" and an
4087
** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
4088
** parameters are set for the explicitly declared column. If there is no
4089
** explicitly declared [INTEGER PRIMARY KEY] column, then the output
4090
** parameters are set as follows:
4093
** data type: "INTEGER"
4094
** collation sequence: "BINARY"
4097
** auto increment: 0
4100
** This function may load one or more schemas from database files. If an
4101
** error occurs during this process, or if the requested table or column
4102
** cannot be found, an [error code] is returned and an error message left
4103
** in the [database connection] (to be retrieved using sqlite3_errmsg()).
4105
** This API is only available if the library was compiled with the
4106
** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined.
4108
SQLITE_API int sqlite3_table_column_metadata(
4109
sqlite3 *db, /* Connection handle */
4110
const char *zDbName, /* Database name or NULL */
4111
const char *zTableName, /* Table name */
4112
const char *zColumnName, /* Column name */
4113
char const **pzDataType, /* OUTPUT: Declared data type */
4114
char const **pzCollSeq, /* OUTPUT: Collation sequence name */
4115
int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */
4116
int *pPrimaryKey, /* OUTPUT: True if column part of PK */
4117
int *pAutoinc /* OUTPUT: True if column is auto-increment */
4121
** CAPI3REF: Load An Extension {H12600} <S20500>
4123
** This interface loads an SQLite extension library from the named file.
4125
** {H12601} The sqlite3_load_extension() interface attempts to load an
4126
** SQLite extension library contained in the file zFile.
4128
** {H12602} The entry point is zProc.
4130
** {H12603} zProc may be 0, in which case the name of the entry point
4131
** defaults to "sqlite3_extension_init".
4133
** {H12604} The sqlite3_load_extension() interface shall return
4134
** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
4136
** {H12605} If an error occurs and pzErrMsg is not 0, then the
4137
** [sqlite3_load_extension()] interface shall attempt to
4138
** fill *pzErrMsg with error message text stored in memory
4139
** obtained from [sqlite3_malloc()]. {END} The calling function
4140
** should free this memory by calling [sqlite3_free()].
4142
** {H12606} Extension loading must be enabled using
4143
** [sqlite3_enable_load_extension()] prior to calling this API,
4144
** otherwise an error will be returned.
4146
SQLITE_API int sqlite3_load_extension(
4147
sqlite3 *db, /* Load the extension into this database connection */
4148
const char *zFile, /* Name of the shared library containing extension */
4149
const char *zProc, /* Entry point. Derived from zFile if 0 */
4150
char **pzErrMsg /* Put error message here if not 0 */
4154
** CAPI3REF: Enable Or Disable Extension Loading {H12620} <S20500>
4156
** So as not to open security holes in older applications that are
4157
** unprepared to deal with extension loading, and as a means of disabling
4158
** extension loading while evaluating user-entered SQL, the following API
4159
** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
4161
** Extension loading is off by default. See ticket #1863.
4163
** {H12621} Call the sqlite3_enable_load_extension() routine with onoff==1
4164
** to turn extension loading on and call it with onoff==0 to turn
4165
** it back off again.
4167
** {H12622} Extension loading is off by default.
4169
SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
4172
** CAPI3REF: Automatically Load An Extensions {H12640} <S20500>
4174
** This API can be invoked at program startup in order to register
4175
** one or more statically linked extensions that will be available
4176
** to all new [database connections]. {END}
4178
** This routine stores a pointer to the extension in an array that is
4179
** obtained from [sqlite3_malloc()]. If you run a memory leak checker
4180
** on your program and it reports a leak because of this array, invoke
4181
** [sqlite3_reset_auto_extension()] prior to shutdown to free the memory.
4183
** {H12641} This function registers an extension entry point that is
4184
** automatically invoked whenever a new [database connection]
4185
** is opened using [sqlite3_open()], [sqlite3_open16()],
4186
** or [sqlite3_open_v2()].
4188
** {H12642} Duplicate extensions are detected so calling this routine
4189
** multiple times with the same extension is harmless.
4191
** {H12643} This routine stores a pointer to the extension in an array
4192
** that is obtained from [sqlite3_malloc()].
4194
** {H12644} Automatic extensions apply across all threads.
4196
SQLITE_API int sqlite3_auto_extension(void (*xEntryPoint)(void));
4199
** CAPI3REF: Reset Automatic Extension Loading {H12660} <S20500>
4201
** This function disables all previously registered automatic
4202
** extensions. {END} It undoes the effect of all prior
4203
** [sqlite3_auto_extension()] calls.
4205
** {H12661} This function disables all previously registered
4206
** automatic extensions.
4208
** {H12662} This function disables automatic extensions in all threads.
4210
SQLITE_API void sqlite3_reset_auto_extension(void);
4213
****** EXPERIMENTAL - subject to change without notice **************
4215
** The interface to the virtual-table mechanism is currently considered
4216
** to be experimental. The interface might change in incompatible ways.
4217
** If this is a problem for you, do not use the interface at this time.
4219
** When the virtual-table mechanism stabilizes, we will declare the
4220
** interface fixed, support it indefinitely, and remove this comment.
4224
** Structures used by the virtual table interface
4226
typedef struct sqlite3_vtab sqlite3_vtab;
4227
typedef struct sqlite3_index_info sqlite3_index_info;
4228
typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
4229
typedef struct sqlite3_module sqlite3_module;
4232
** CAPI3REF: Virtual Table Object {H18000} <S20400>
4233
** KEYWORDS: sqlite3_module {virtual table module}
4236
** This structure, sometimes called a a "virtual table module",
4237
** defines the implementation of a [virtual tables].
4238
** This structure consists mostly of methods for the module.
4240
** A virtual table module is created by filling in a persistent
4241
** instance of this structure and passing a pointer to that instance
4242
** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
4243
** The registration remains valid until it is replaced by a different
4244
** module or until the [database connection] closes. The content
4245
** of this structure must not change while it is registered with
4246
** any database connection.
4248
struct sqlite3_module {
4250
int (*xCreate)(sqlite3*, void *pAux,
4251
int argc, const char *const*argv,
4252
sqlite3_vtab **ppVTab, char**);
4253
int (*xConnect)(sqlite3*, void *pAux,
4254
int argc, const char *const*argv,
4255
sqlite3_vtab **ppVTab, char**);
4256
int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
4257
int (*xDisconnect)(sqlite3_vtab *pVTab);
4258
int (*xDestroy)(sqlite3_vtab *pVTab);
4259
int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
4260
int (*xClose)(sqlite3_vtab_cursor*);
4261
int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
4262
int argc, sqlite3_value **argv);
4263
int (*xNext)(sqlite3_vtab_cursor*);
4264
int (*xEof)(sqlite3_vtab_cursor*);
4265
int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
4266
int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
4267
int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
4268
int (*xBegin)(sqlite3_vtab *pVTab);
4269
int (*xSync)(sqlite3_vtab *pVTab);
4270
int (*xCommit)(sqlite3_vtab *pVTab);
4271
int (*xRollback)(sqlite3_vtab *pVTab);
4272
int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
4273
void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
4275
int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
4279
** CAPI3REF: Virtual Table Indexing Information {H18100} <S20400>
4280
** KEYWORDS: sqlite3_index_info
4283
** The sqlite3_index_info structure and its substructures is used to
4284
** pass information into and receive the reply from the [xBestIndex]
4285
** method of a [virtual table module]. The fields under **Inputs** are the
4286
** inputs to xBestIndex and are read-only. xBestIndex inserts its
4287
** results into the **Outputs** fields.
4289
** The aConstraint[] array records WHERE clause constraints of the form:
4291
** <pre>column OP expr</pre>
4293
** where OP is =, <, <=, >, or >=. The particular operator is
4294
** stored in aConstraint[].op. The index of the column is stored in
4295
** aConstraint[].iColumn. aConstraint[].usable is TRUE if the
4296
** expr on the right-hand side can be evaluated (and thus the constraint
4297
** is usable) and false if it cannot.
4299
** The optimizer automatically inverts terms of the form "expr OP column"
4300
** and makes other simplifications to the WHERE clause in an attempt to
4301
** get as many WHERE clause terms into the form shown above as possible.
4302
** The aConstraint[] array only reports WHERE clause terms in the correct
4303
** form that refer to the particular virtual table being queried.
4305
** Information about the ORDER BY clause is stored in aOrderBy[].
4306
** Each term of aOrderBy records a column of the ORDER BY clause.
4308
** The [xBestIndex] method must fill aConstraintUsage[] with information
4309
** about what parameters to pass to xFilter. If argvIndex>0 then
4310
** the right-hand side of the corresponding aConstraint[] is evaluated
4311
** and becomes the argvIndex-th entry in argv. If aConstraintUsage[].omit
4312
** is true, then the constraint is assumed to be fully handled by the
4313
** virtual table and is not checked again by SQLite.
4315
** The idxNum and idxPtr values are recorded and passed into the
4316
** [xFilter] method.
4317
** [sqlite3_free()] is used to free idxPtr if and only iff
4318
** needToFreeIdxPtr is true.
4320
** The orderByConsumed means that output from [xFilter]/[xNext] will occur in
4321
** the correct order to satisfy the ORDER BY clause so that no separate
4322
** sorting step is required.
4324
** The estimatedCost value is an estimate of the cost of doing the
4325
** particular lookup. A full scan of a table with N entries should have
4326
** a cost of N. A binary search of a table of N entries should have a
4327
** cost of approximately log(N).
4329
struct sqlite3_index_info {
4331
int nConstraint; /* Number of entries in aConstraint */
4332
struct sqlite3_index_constraint {
4333
int iColumn; /* Column on left-hand side of constraint */
4334
unsigned char op; /* Constraint operator */
4335
unsigned char usable; /* True if this constraint is usable */
4336
int iTermOffset; /* Used internally - xBestIndex should ignore */
4337
} *aConstraint; /* Table of WHERE clause constraints */
4338
int nOrderBy; /* Number of terms in the ORDER BY clause */
4339
struct sqlite3_index_orderby {
4340
int iColumn; /* Column number */
4341
unsigned char desc; /* True for DESC. False for ASC. */
4342
} *aOrderBy; /* The ORDER BY clause */
4344
struct sqlite3_index_constraint_usage {
4345
int argvIndex; /* if >0, constraint is part of argv to xFilter */
4346
unsigned char omit; /* Do not code a test for this constraint */
4347
} *aConstraintUsage;
4348
int idxNum; /* Number used to identify the index */
4349
char *idxStr; /* String, possibly obtained from sqlite3_malloc */
4350
int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */
4351
int orderByConsumed; /* True if output is already ordered */
4352
double estimatedCost; /* Estimated cost of using this index */
4354
#define SQLITE_INDEX_CONSTRAINT_EQ 2
4355
#define SQLITE_INDEX_CONSTRAINT_GT 4
4356
#define SQLITE_INDEX_CONSTRAINT_LE 8
4357
#define SQLITE_INDEX_CONSTRAINT_LT 16
4358
#define SQLITE_INDEX_CONSTRAINT_GE 32
4359
#define SQLITE_INDEX_CONSTRAINT_MATCH 64
4362
** CAPI3REF: Register A Virtual Table Implementation {H18200} <S20400>
4365
** This routine is used to register a new [virtual table module] name.
4366
** Module names must be registered before
4367
** creating a new [virtual table] using the module, or before using a
4368
** preexisting [virtual table] for the module.
4370
** The module name is registered on the [database connection] specified
4371
** by the first parameter. The name of the module is given by the
4372
** second parameter. The third parameter is a pointer to
4373
** the implementation of the [virtual table module]. The fourth
4374
** parameter is an arbitrary client data pointer that is passed through
4375
** into the [xCreate] and [xConnect] methods of the virtual table module
4376
** when a new virtual table is be being created or reinitialized.
4378
** This interface has exactly the same effect as calling
4379
** [sqlite3_create_module_v2()] with a NULL client data destructor.
4381
SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_create_module(
4382
sqlite3 *db, /* SQLite connection to register module with */
4383
const char *zName, /* Name of the module */
4384
const sqlite3_module *p, /* Methods for the module */
4385
void *pClientData /* Client data for xCreate/xConnect */
4389
** CAPI3REF: Register A Virtual Table Implementation {H18210} <S20400>
4392
** This routine is identical to the [sqlite3_create_module()] method,
4393
** except that it has an extra parameter to specify
4394
** a destructor function for the client data pointer. SQLite will
4395
** invoke the destructor function (if it is not NULL) when SQLite
4396
** no longer needs the pClientData pointer.
4398
SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_create_module_v2(
4399
sqlite3 *db, /* SQLite connection to register module with */
4400
const char *zName, /* Name of the module */
4401
const sqlite3_module *p, /* Methods for the module */
4402
void *pClientData, /* Client data for xCreate/xConnect */
4403
void(*xDestroy)(void*) /* Module destructor function */
4407
** CAPI3REF: Virtual Table Instance Object {H18010} <S20400>
4408
** KEYWORDS: sqlite3_vtab
4411
** Every [virtual table module] implementation uses a subclass
4412
** of the following structure to describe a particular instance
4413
** of the [virtual table]. Each subclass will
4414
** be tailored to the specific needs of the module implementation.
4415
** The purpose of this superclass is to define certain fields that are
4416
** common to all module implementations.
4418
** Virtual tables methods can set an error message by assigning a
4419
** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should
4420
** take care that any prior string is freed by a call to [sqlite3_free()]
4421
** prior to assigning a new string to zErrMsg. After the error message
4422
** is delivered up to the client application, the string will be automatically
4423
** freed by sqlite3_free() and the zErrMsg field will be zeroed.
4425
struct sqlite3_vtab {
4426
const sqlite3_module *pModule; /* The module for this virtual table */
4427
int nRef; /* NO LONGER USED */
4428
char *zErrMsg; /* Error message from sqlite3_mprintf() */
4429
/* Virtual table implementations will typically add additional fields */
4433
** CAPI3REF: Virtual Table Cursor Object {H18020} <S20400>
4434
** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
4437
** Every [virtual table module] implementation uses a subclass of the
4438
** following structure to describe cursors that point into the
4439
** [virtual table] and are used
4440
** to loop through the virtual table. Cursors are created using the
4441
** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
4442
** by the [sqlite3_module.xClose | xClose] method. Cussors are used
4443
** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
4444
** of the module. Each module implementation will define
4445
** the content of a cursor structure to suit its own needs.
4447
** This superclass exists in order to define fields of the cursor that
4448
** are common to all implementations.
4450
struct sqlite3_vtab_cursor {
4451
sqlite3_vtab *pVtab; /* Virtual table of this cursor */
4452
/* Virtual table implementations will typically add additional fields */
4456
** CAPI3REF: Declare The Schema Of A Virtual Table {H18280} <S20400>
4459
** The [xCreate] and [xConnect] methods of a
4460
** [virtual table module] call this interface
4461
** to declare the format (the names and datatypes of the columns) of
4462
** the virtual tables they implement.
4464
SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
4467
** CAPI3REF: Overload A Function For A Virtual Table {H18300} <S20400>
4470
** Virtual tables can provide alternative implementations of functions
4471
** using the [xFindFunction] method of the [virtual table module].
4472
** But global versions of those functions
4473
** must exist in order to be overloaded.
4475
** This API makes sure a global version of a function with a particular
4476
** name and number of parameters exists. If no such function exists
4477
** before this API is called, a new function is created. The implementation
4478
** of the new function always causes an exception to be thrown. So
4479
** the new function is not good for anything by itself. Its only
4480
** purpose is to be a placeholder function that can be overloaded
4481
** by a [virtual table].
4483
SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
4486
** The interface to the virtual-table mechanism defined above (back up
4487
** to a comment remarkably similar to this one) is currently considered
4488
** to be experimental. The interface might change in incompatible ways.
4489
** If this is a problem for you, do not use the interface at this time.
4491
** When the virtual-table mechanism stabilizes, we will declare the
4492
** interface fixed, support it indefinitely, and remove this comment.
4494
****** EXPERIMENTAL - subject to change without notice **************
4498
** CAPI3REF: A Handle To An Open BLOB {H17800} <S30230>
4499
** KEYWORDS: {BLOB handle} {BLOB handles}
4501
** An instance of this object represents an open BLOB on which
4502
** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
4503
** Objects of this type are created by [sqlite3_blob_open()]
4504
** and destroyed by [sqlite3_blob_close()].
4505
** The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
4506
** can be used to read or write small subsections of the BLOB.
4507
** The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
4509
typedef struct sqlite3_blob sqlite3_blob;
4512
** CAPI3REF: Open A BLOB For Incremental I/O {H17810} <S30230>
4514
** This interfaces opens a [BLOB handle | handle] to the BLOB located
4515
** in row iRow, column zColumn, table zTable in database zDb;
4516
** in other words, the same BLOB that would be selected by:
4519
** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
4522
** If the flags parameter is non-zero, then the BLOB is opened for read
4523
** and write access. If it is zero, the BLOB is opened for read access.
4524
** It is not possible to open a column that is part of an index or primary
4525
** key for writing. ^If [foreign key constraints] are enabled, it is
4526
** not possible to open a column that is part of a [child key] for writing.
4528
** Note that the database name is not the filename that contains
4529
** the database but rather the symbolic name of the database that
4530
** is assigned when the database is connected using [ATTACH].
4531
** For the main database file, the database name is "main".
4532
** For TEMP tables, the database name is "temp".
4534
** On success, [SQLITE_OK] is returned and the new [BLOB handle] is written
4535
** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set
4536
** to be a null pointer.
4537
** This function sets the [database connection] error code and message
4538
** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related
4539
** functions. Note that the *ppBlob variable is always initialized in a
4540
** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob
4541
** regardless of the success or failure of this routine.
4543
** If the row that a BLOB handle points to is modified by an
4544
** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
4545
** then the BLOB handle is marked as "expired".
4546
** This is true if any column of the row is changed, even a column
4547
** other than the one the BLOB handle is open on.
4548
** Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
4549
** a expired BLOB handle fail with an return code of [SQLITE_ABORT].
4550
** Changes written into a BLOB prior to the BLOB expiring are not
4551
** rollback by the expiration of the BLOB. Such changes will eventually
4552
** commit if the transaction continues to completion.
4554
** Use the [sqlite3_blob_bytes()] interface to determine the size of
4555
** the opened blob. The size of a blob may not be changed by this
4556
** interface. Use the [UPDATE] SQL command to change the size of a
4559
** The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
4560
** and the built-in [zeroblob] SQL function can be used, if desired,
4561
** to create an empty, zero-filled blob in which to read or write using
4564
** To avoid a resource leak, every open [BLOB handle] should eventually
4565
** be released by a call to [sqlite3_blob_close()].
4568
** [H17813] [H17814] [H17816] [H17819] [H17821] [H17824]
4570
SQLITE_API int sqlite3_blob_open(
4574
const char *zColumn,
4577
sqlite3_blob **ppBlob
4581
** CAPI3REF: Close A BLOB Handle {H17830} <S30230>
4583
** Closes an open [BLOB handle].
4585
** Closing a BLOB shall cause the current transaction to commit
4586
** if there are no other BLOBs, no pending prepared statements, and the
4587
** database connection is in [autocommit mode].
4588
** If any writes were made to the BLOB, they might be held in cache
4589
** until the close operation if they will fit.
4591
** Closing the BLOB often forces the changes
4592
** out to disk and so if any I/O errors occur, they will likely occur
4593
** at the time when the BLOB is closed. Any errors that occur during
4594
** closing are reported as a non-zero return value.
4596
** The BLOB is closed unconditionally. Even if this routine returns
4597
** an error code, the BLOB is still closed.
4599
** Calling this routine with a null pointer (which as would be returned
4600
** by failed call to [sqlite3_blob_open()]) is a harmless no-op.
4603
** [H17833] [H17836] [H17839]
4605
SQLITE_API int sqlite3_blob_close(sqlite3_blob *);
4608
** CAPI3REF: Return The Size Of An Open BLOB {H17840} <S30230>
4610
** Returns the size in bytes of the BLOB accessible via the
4611
** successfully opened [BLOB handle] in its only argument. The
4612
** incremental blob I/O routines can only read or overwriting existing
4613
** blob content; they cannot change the size of a blob.
4615
** This routine only works on a [BLOB handle] which has been created
4616
** by a prior successful call to [sqlite3_blob_open()] and which has not
4617
** been closed by [sqlite3_blob_close()]. Passing any other pointer in
4618
** to this routine results in undefined and probably undesirable behavior.
4623
SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *);
4626
** CAPI3REF: Read Data From A BLOB Incrementally {H17850} <S30230>
4628
** This function is used to read data from an open [BLOB handle] into a
4629
** caller-supplied buffer. N bytes of data are copied into buffer Z
4630
** from the open BLOB, starting at offset iOffset.
4632
** If offset iOffset is less than N bytes from the end of the BLOB,
4633
** [SQLITE_ERROR] is returned and no data is read. If N or iOffset is
4634
** less than zero, [SQLITE_ERROR] is returned and no data is read.
4635
** The size of the blob (and hence the maximum value of N+iOffset)
4636
** can be determined using the [sqlite3_blob_bytes()] interface.
4638
** An attempt to read from an expired [BLOB handle] fails with an
4639
** error code of [SQLITE_ABORT].
4641
** On success, SQLITE_OK is returned.
4642
** Otherwise, an [error code] or an [extended error code] is returned.
4644
** This routine only works on a [BLOB handle] which has been created
4645
** by a prior successful call to [sqlite3_blob_open()] and which has not
4646
** been closed by [sqlite3_blob_close()]. Passing any other pointer in
4647
** to this routine results in undefined and probably undesirable behavior.
4649
** See also: [sqlite3_blob_write()].
4652
** [H17853] [H17856] [H17859] [H17862] [H17863] [H17865] [H17868]
4654
SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
4657
** CAPI3REF: Write Data Into A BLOB Incrementally {H17870} <S30230>
4659
** This function is used to write data into an open [BLOB handle] from a
4660
** caller-supplied buffer. N bytes of data are copied from the buffer Z
4661
** into the open BLOB, starting at offset iOffset.
4663
** If the [BLOB handle] passed as the first argument was not opened for
4664
** writing (the flags parameter to [sqlite3_blob_open()] was zero),
4665
** this function returns [SQLITE_READONLY].
4667
** This function may only modify the contents of the BLOB; it is
4668
** not possible to increase the size of a BLOB using this API.
4669
** If offset iOffset is less than N bytes from the end of the BLOB,
4670
** [SQLITE_ERROR] is returned and no data is written. If N is
4671
** less than zero [SQLITE_ERROR] is returned and no data is written.
4672
** The size of the BLOB (and hence the maximum value of N+iOffset)
4673
** can be determined using the [sqlite3_blob_bytes()] interface.
4675
** An attempt to write to an expired [BLOB handle] fails with an
4676
** error code of [SQLITE_ABORT]. Writes to the BLOB that occurred
4677
** before the [BLOB handle] expired are not rolled back by the
4678
** expiration of the handle, though of course those changes might
4679
** have been overwritten by the statement that expired the BLOB handle
4680
** or by other independent statements.
4682
** On success, SQLITE_OK is returned.
4683
** Otherwise, an [error code] or an [extended error code] is returned.
4685
** This routine only works on a [BLOB handle] which has been created
4686
** by a prior successful call to [sqlite3_blob_open()] and which has not
4687
** been closed by [sqlite3_blob_close()]. Passing any other pointer in
4688
** to this routine results in undefined and probably undesirable behavior.
4690
** See also: [sqlite3_blob_read()].
4693
** [H17873] [H17874] [H17875] [H17876] [H17877] [H17879] [H17882] [H17885]
4696
SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
4699
** CAPI3REF: Virtual File System Objects {H11200} <S20100>
4701
** A virtual filesystem (VFS) is an [sqlite3_vfs] object
4702
** that SQLite uses to interact
4703
** with the underlying operating system. Most SQLite builds come with a
4704
** single default VFS that is appropriate for the host computer.
4705
** New VFSes can be registered and existing VFSes can be unregistered.
4706
** The following interfaces are provided.
4708
** The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
4709
** Names are case sensitive.
4710
** Names are zero-terminated UTF-8 strings.
4711
** If there is no match, a NULL pointer is returned.
4712
** If zVfsName is NULL then the default VFS is returned.
4714
** New VFSes are registered with sqlite3_vfs_register().
4715
** Each new VFS becomes the default VFS if the makeDflt flag is set.
4716
** The same VFS can be registered multiple times without injury.
4717
** To make an existing VFS into the default VFS, register it again
4718
** with the makeDflt flag set. If two different VFSes with the
4719
** same name are registered, the behavior is undefined. If a
4720
** VFS is registered with a name that is NULL or an empty string,
4721
** then the behavior is undefined.
4723
** Unregister a VFS with the sqlite3_vfs_unregister() interface.
4724
** If the default VFS is unregistered, another VFS is chosen as
4725
** the default. The choice for the new VFS is arbitrary.
4728
** [H11203] [H11206] [H11209] [H11212] [H11215] [H11218]
4730
SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
4731
SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
4732
SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*);
4735
** CAPI3REF: Mutexes {H17000} <S20000>
4737
** The SQLite core uses these routines for thread
4738
** synchronization. Though they are intended for internal
4739
** use by SQLite, code that links against SQLite is
4740
** permitted to use any of these routines.
4742
** The SQLite source code contains multiple implementations
4743
** of these mutex routines. An appropriate implementation
4744
** is selected automatically at compile-time. The following
4745
** implementations are available in the SQLite core:
4748
** <li> SQLITE_MUTEX_OS2
4749
** <li> SQLITE_MUTEX_PTHREAD
4750
** <li> SQLITE_MUTEX_W32
4751
** <li> SQLITE_MUTEX_NOOP
4754
** The SQLITE_MUTEX_NOOP implementation is a set of routines
4755
** that does no real locking and is appropriate for use in
4756
** a single-threaded application. The SQLITE_MUTEX_OS2,
4757
** SQLITE_MUTEX_PTHREAD, and SQLITE_MUTEX_W32 implementations
4758
** are appropriate for use on OS/2, Unix, and Windows.
4760
** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
4761
** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
4762
** implementation is included with the library. In this case the
4763
** application must supply a custom mutex implementation using the
4764
** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
4765
** before calling sqlite3_initialize() or any other public sqlite3_
4766
** function that calls sqlite3_initialize().
4768
** {H17011} The sqlite3_mutex_alloc() routine allocates a new
4769
** mutex and returns a pointer to it. {H17012} If it returns NULL
4770
** that means that a mutex could not be allocated. {H17013} SQLite
4771
** will unwind its stack and return an error. {H17014} The argument
4772
** to sqlite3_mutex_alloc() is one of these integer constants:
4775
** <li> SQLITE_MUTEX_FAST
4776
** <li> SQLITE_MUTEX_RECURSIVE
4777
** <li> SQLITE_MUTEX_STATIC_MASTER
4778
** <li> SQLITE_MUTEX_STATIC_MEM
4779
** <li> SQLITE_MUTEX_STATIC_MEM2
4780
** <li> SQLITE_MUTEX_STATIC_PRNG
4781
** <li> SQLITE_MUTEX_STATIC_LRU
4782
** <li> SQLITE_MUTEX_STATIC_LRU2
4785
** {H17015} The first two constants cause sqlite3_mutex_alloc() to create
4786
** a new mutex. The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
4787
** is used but not necessarily so when SQLITE_MUTEX_FAST is used. {END}
4788
** The mutex implementation does not need to make a distinction
4789
** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
4790
** not want to. {H17016} But SQLite will only request a recursive mutex in
4791
** cases where it really needs one. {END} If a faster non-recursive mutex
4792
** implementation is available on the host platform, the mutex subsystem
4793
** might return such a mutex in response to SQLITE_MUTEX_FAST.
4795
** {H17017} The other allowed parameters to sqlite3_mutex_alloc() each return
4796
** a pointer to a static preexisting mutex. {END} Six static mutexes are
4797
** used by the current version of SQLite. Future versions of SQLite
4798
** may add additional static mutexes. Static mutexes are for internal
4799
** use by SQLite only. Applications that use SQLite mutexes should
4800
** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
4801
** SQLITE_MUTEX_RECURSIVE.
4803
** {H17018} Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
4804
** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
4805
** returns a different mutex on every call. {H17034} But for the static
4806
** mutex types, the same mutex is returned on every call that has
4807
** the same type number.
4809
** {H17019} The sqlite3_mutex_free() routine deallocates a previously
4810
** allocated dynamic mutex. {H17020} SQLite is careful to deallocate every
4811
** dynamic mutex that it allocates. {A17021} The dynamic mutexes must not be in
4812
** use when they are deallocated. {A17022} Attempting to deallocate a static
4813
** mutex results in undefined behavior. {H17023} SQLite never deallocates
4814
** a static mutex. {END}
4816
** The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
4817
** to enter a mutex. {H17024} If another thread is already within the mutex,
4818
** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
4819
** SQLITE_BUSY. {H17025} The sqlite3_mutex_try() interface returns [SQLITE_OK]
4820
** upon successful entry. {H17026} Mutexes created using
4821
** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
4822
** {H17027} In such cases the,
4823
** mutex must be exited an equal number of times before another thread
4824
** can enter. {A17028} If the same thread tries to enter any other
4825
** kind of mutex more than once, the behavior is undefined.
4826
** {H17029} SQLite will never exhibit
4827
** such behavior in its own use of mutexes.
4829
** Some systems (for example, Windows 95) do not support the operation
4830
** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try()
4831
** will always return SQLITE_BUSY. {H17030} The SQLite core only ever uses
4832
** sqlite3_mutex_try() as an optimization so this is acceptable behavior.
4834
** {H17031} The sqlite3_mutex_leave() routine exits a mutex that was
4835
** previously entered by the same thread. {A17032} The behavior
4836
** is undefined if the mutex is not currently entered by the
4837
** calling thread or is not currently allocated. {H17033} SQLite will
4838
** never do either. {END}
4840
** If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
4841
** sqlite3_mutex_leave() is a NULL pointer, then all three routines
4842
** behave as no-ops.
4844
** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
4846
SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int);
4847
SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*);
4848
SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*);
4849
SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*);
4850
SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*);
4853
** CAPI3REF: Mutex Methods Object {H17120} <S20130>
4856
** An instance of this structure defines the low-level routines
4857
** used to allocate and use mutexes.
4859
** Usually, the default mutex implementations provided by SQLite are
4860
** sufficient, however the user has the option of substituting a custom
4861
** implementation for specialized deployments or systems for which SQLite
4862
** does not provide a suitable implementation. In this case, the user
4863
** creates and populates an instance of this structure to pass
4864
** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
4865
** Additionally, an instance of this structure can be used as an
4866
** output variable when querying the system for the current mutex
4867
** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
4869
** The xMutexInit method defined by this structure is invoked as
4870
** part of system initialization by the sqlite3_initialize() function.
4871
** {H17001} The xMutexInit routine shall be called by SQLite once for each
4872
** effective call to [sqlite3_initialize()].
4874
** The xMutexEnd method defined by this structure is invoked as
4875
** part of system shutdown by the sqlite3_shutdown() function. The
4876
** implementation of this method is expected to release all outstanding
4877
** resources obtained by the mutex methods implementation, especially
4878
** those obtained by the xMutexInit method. {H17003} The xMutexEnd()
4879
** interface shall be invoked once for each call to [sqlite3_shutdown()].
4881
** The remaining seven methods defined by this structure (xMutexAlloc,
4882
** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
4883
** xMutexNotheld) implement the following interfaces (respectively):
4886
** <li> [sqlite3_mutex_alloc()] </li>
4887
** <li> [sqlite3_mutex_free()] </li>
4888
** <li> [sqlite3_mutex_enter()] </li>
4889
** <li> [sqlite3_mutex_try()] </li>
4890
** <li> [sqlite3_mutex_leave()] </li>
4891
** <li> [sqlite3_mutex_held()] </li>
4892
** <li> [sqlite3_mutex_notheld()] </li>
4895
** The only difference is that the public sqlite3_XXX functions enumerated
4896
** above silently ignore any invocations that pass a NULL pointer instead
4897
** of a valid mutex handle. The implementations of the methods defined
4898
** by this structure are not required to handle this case, the results
4899
** of passing a NULL pointer instead of a valid mutex handle are undefined
4900
** (i.e. it is acceptable to provide an implementation that segfaults if
4901
** it is passed a NULL pointer).
4903
** The xMutexInit() method must be threadsafe. It must be harmless to
4904
** invoke xMutexInit() mutiple times within the same process and without
4905
** intervening calls to xMutexEnd(). Second and subsequent calls to
4906
** xMutexInit() must be no-ops.
4908
** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
4909
** and its associates). Similarly, xMutexAlloc() must not use SQLite memory
4910
** allocation for a static mutex. However xMutexAlloc() may use SQLite
4911
** memory allocation for a fast or recursive mutex.
4913
** SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
4914
** called, but only if the prior call to xMutexInit returned SQLITE_OK.
4915
** If xMutexInit fails in any way, it is expected to clean up after itself
4916
** prior to returning.
4918
typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
4919
struct sqlite3_mutex_methods {
4920
int (*xMutexInit)(void);
4921
int (*xMutexEnd)(void);
4922
sqlite3_mutex *(*xMutexAlloc)(int);
4923
void (*xMutexFree)(sqlite3_mutex *);
4924
void (*xMutexEnter)(sqlite3_mutex *);
4925
int (*xMutexTry)(sqlite3_mutex *);
4926
void (*xMutexLeave)(sqlite3_mutex *);
4927
int (*xMutexHeld)(sqlite3_mutex *);
4928
int (*xMutexNotheld)(sqlite3_mutex *);
4932
** CAPI3REF: Mutex Verification Routines {H17080} <S20130> <S30800>
4934
** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
4935
** are intended for use inside assert() statements. {H17081} The SQLite core
4936
** never uses these routines except inside an assert() and applications
4937
** are advised to follow the lead of the core. {H17082} The core only
4938
** provides implementations for these routines when it is compiled
4939
** with the SQLITE_DEBUG flag. {A17087} External mutex implementations
4940
** are only required to provide these routines if SQLITE_DEBUG is
4941
** defined and if NDEBUG is not defined.
4943
** {H17083} These routines should return true if the mutex in their argument
4944
** is held or not held, respectively, by the calling thread.
4946
** {X17084} The implementation is not required to provided versions of these
4947
** routines that actually work. If the implementation does not provide working
4948
** versions of these routines, it should at least provide stubs that always
4949
** return true so that one does not get spurious assertion failures.
4951
** {H17085} If the argument to sqlite3_mutex_held() is a NULL pointer then
4952
** the routine should return 1. {END} This seems counter-intuitive since
4953
** clearly the mutex cannot be held if it does not exist. But the
4954
** the reason the mutex does not exist is because the build is not
4955
** using mutexes. And we do not want the assert() containing the
4956
** call to sqlite3_mutex_held() to fail, so a non-zero return is
4957
** the appropriate thing to do. {H17086} The sqlite3_mutex_notheld()
4958
** interface should also return 1 when given a NULL pointer.
4960
SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*);
4961
SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*);
4964
** CAPI3REF: Mutex Types {H17001} <H17000>
4966
** The [sqlite3_mutex_alloc()] interface takes a single argument
4967
** which is one of these integer constants.
4969
** The set of static mutexes may change from one SQLite release to the
4970
** next. Applications that override the built-in mutex logic must be
4971
** prepared to accommodate additional static mutexes.
4973
#define SQLITE_MUTEX_FAST 0
4974
#define SQLITE_MUTEX_RECURSIVE 1
4975
#define SQLITE_MUTEX_STATIC_MASTER 2
4976
#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */
4977
#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */
4978
#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */
4979
#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */
4980
#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */
4981
#define SQLITE_MUTEX_STATIC_LRU2 7 /* lru page list */
4984
** CAPI3REF: Retrieve the mutex for a database connection {H17002} <H17000>
4986
** This interface returns a pointer the [sqlite3_mutex] object that
4987
** serializes access to the [database connection] given in the argument
4988
** when the [threading mode] is Serialized.
4989
** If the [threading mode] is Single-thread or Multi-thread then this
4990
** routine returns a NULL pointer.
4992
SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
4995
** CAPI3REF: Low-Level Control Of Database Files {H11300} <S30800>
4997
** {H11301} The [sqlite3_file_control()] interface makes a direct call to the
4998
** xFileControl method for the [sqlite3_io_methods] object associated
4999
** with a particular database identified by the second argument. {H11302} The
5000
** name of the database is the name assigned to the database by the
5001
** <a href="lang_attach.html">ATTACH</a> SQL command that opened the
5002
** database. {H11303} To control the main database file, use the name "main"
5003
** or a NULL pointer. {H11304} The third and fourth parameters to this routine
5004
** are passed directly through to the second and third parameters of
5005
** the xFileControl method. {H11305} The return value of the xFileControl
5006
** method becomes the return value of this routine.
5008
** {H11306} If the second parameter (zDbName) does not match the name of any
5009
** open database file, then SQLITE_ERROR is returned. {H11307} This error
5010
** code is not remembered and will not be recalled by [sqlite3_errcode()]
5011
** or [sqlite3_errmsg()]. {A11308} The underlying xFileControl method might
5012
** also return SQLITE_ERROR. {A11309} There is no way to distinguish between
5013
** an incorrect zDbName and an SQLITE_ERROR return from the underlying
5014
** xFileControl method. {END}
5016
** See also: [SQLITE_FCNTL_LOCKSTATE]
5018
SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
5021
** CAPI3REF: Testing Interface {H11400} <S30800>
5023
** The sqlite3_test_control() interface is used to read out internal
5024
** state of SQLite and to inject faults into SQLite for testing
5025
** purposes. The first parameter is an operation code that determines
5026
** the number, meaning, and operation of all subsequent parameters.
5028
** This interface is not for use by applications. It exists solely
5029
** for verifying the correct operation of the SQLite library. Depending
5030
** on how the SQLite library is compiled, this interface might not exist.
5032
** The details of the operation codes, their meanings, the parameters
5033
** they take, and what they do are all subject to change without notice.
5034
** Unlike most of the SQLite API, this function is not guaranteed to
5035
** operate consistently from one release to the next.
5037
SQLITE_API int sqlite3_test_control(int op, ...);
5040
** CAPI3REF: Testing Interface Operation Codes {H11410} <H11400>
5042
** These constants are the valid operation code parameters used
5043
** as the first argument to [sqlite3_test_control()].
5045
** These parameters and their meanings are subject to change
5046
** without notice. These values are for testing purposes only.
5047
** Applications should not use any of these parameters or the
5048
** [sqlite3_test_control()] interface.
5050
#define SQLITE_TESTCTRL_PRNG_SAVE 5
5051
#define SQLITE_TESTCTRL_PRNG_RESTORE 6
5052
#define SQLITE_TESTCTRL_PRNG_RESET 7
5053
#define SQLITE_TESTCTRL_BITVEC_TEST 8
5054
#define SQLITE_TESTCTRL_FAULT_INSTALL 9
5055
#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10
5056
#define SQLITE_TESTCTRL_PENDING_BYTE 11
5057
#define SQLITE_TESTCTRL_ASSERT 12
5058
#define SQLITE_TESTCTRL_ALWAYS 13
5059
#define SQLITE_TESTCTRL_RESERVE 14
5062
** CAPI3REF: SQLite Runtime Status {H17200} <S60200>
5065
** This interface is used to retrieve runtime status information
5066
** about the preformance of SQLite, and optionally to reset various
5067
** highwater marks. The first argument is an integer code for
5068
** the specific parameter to measure. Recognized integer codes
5069
** are of the form [SQLITE_STATUS_MEMORY_USED | SQLITE_STATUS_...].
5070
** The current value of the parameter is returned into *pCurrent.
5071
** The highest recorded value is returned in *pHighwater. If the
5072
** resetFlag is true, then the highest record value is reset after
5073
** *pHighwater is written. Some parameters do not record the highest
5074
** value. For those parameters
5075
** nothing is written into *pHighwater and the resetFlag is ignored.
5076
** Other parameters record only the highwater mark and not the current
5077
** value. For these latter parameters nothing is written into *pCurrent.
5079
** This routine returns SQLITE_OK on success and a non-zero
5080
** [error code] on failure.
5082
** This routine is threadsafe but is not atomic. This routine can be
5083
** called while other threads are running the same or different SQLite
5084
** interfaces. However the values returned in *pCurrent and
5085
** *pHighwater reflect the status of SQLite at different points in time
5086
** and it is possible that another thread might change the parameter
5087
** in between the times when *pCurrent and *pHighwater are written.
5089
** See also: [sqlite3_db_status()]
5091
SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
5095
** CAPI3REF: Status Parameters {H17250} <H17200>
5098
** These integer constants designate various run-time status parameters
5099
** that can be returned by [sqlite3_status()].
5102
** <dt>SQLITE_STATUS_MEMORY_USED</dt>
5103
** <dd>This parameter is the current amount of memory checked out
5104
** using [sqlite3_malloc()], either directly or indirectly. The
5105
** figure includes calls made to [sqlite3_malloc()] by the application
5106
** and internal memory usage by the SQLite library. Scratch memory
5107
** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache
5108
** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
5109
** this parameter. The amount returned is the sum of the allocation
5110
** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>
5112
** <dt>SQLITE_STATUS_MALLOC_SIZE</dt>
5113
** <dd>This parameter records the largest memory allocation request
5114
** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
5115
** internal equivalents). Only the value returned in the
5116
** *pHighwater parameter to [sqlite3_status()] is of interest.
5117
** The value written into the *pCurrent parameter is undefined.</dd>
5119
** <dt>SQLITE_STATUS_PAGECACHE_USED</dt>
5120
** <dd>This parameter returns the number of pages used out of the
5121
** [pagecache memory allocator] that was configured using
5122
** [SQLITE_CONFIG_PAGECACHE]. The
5123
** value returned is in pages, not in bytes.</dd>
5125
** <dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
5126
** <dd>This parameter returns the number of bytes of page cache
5127
** allocation which could not be statisfied by the [SQLITE_CONFIG_PAGECACHE]
5128
** buffer and where forced to overflow to [sqlite3_malloc()]. The
5129
** returned value includes allocations that overflowed because they
5130
** where too large (they were larger than the "sz" parameter to
5131
** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
5132
** no space was left in the page cache.</dd>
5134
** <dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
5135
** <dd>This parameter records the largest memory allocation request
5136
** handed to [pagecache memory allocator]. Only the value returned in the
5137
** *pHighwater parameter to [sqlite3_status()] is of interest.
5138
** The value written into the *pCurrent parameter is undefined.</dd>
5140
** <dt>SQLITE_STATUS_SCRATCH_USED</dt>
5141
** <dd>This parameter returns the number of allocations used out of the
5142
** [scratch memory allocator] configured using
5143
** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not
5144
** in bytes. Since a single thread may only have one scratch allocation
5145
** outstanding at time, this parameter also reports the number of threads
5146
** using scratch memory at the same time.</dd>
5148
** <dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
5149
** <dd>This parameter returns the number of bytes of scratch memory
5150
** allocation which could not be statisfied by the [SQLITE_CONFIG_SCRATCH]
5151
** buffer and where forced to overflow to [sqlite3_malloc()]. The values
5152
** returned include overflows because the requested allocation was too
5153
** larger (that is, because the requested allocation was larger than the
5154
** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer
5155
** slots were available.
5158
** <dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
5159
** <dd>This parameter records the largest memory allocation request
5160
** handed to [scratch memory allocator]. Only the value returned in the
5161
** *pHighwater parameter to [sqlite3_status()] is of interest.
5162
** The value written into the *pCurrent parameter is undefined.</dd>
5164
** <dt>SQLITE_STATUS_PARSER_STACK</dt>
5165
** <dd>This parameter records the deepest parser stack. It is only
5166
** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>
5169
** New status parameters may be added from time to time.
5171
#define SQLITE_STATUS_MEMORY_USED 0
5172
#define SQLITE_STATUS_PAGECACHE_USED 1
5173
#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2
5174
#define SQLITE_STATUS_SCRATCH_USED 3
5175
#define SQLITE_STATUS_SCRATCH_OVERFLOW 4
5176
#define SQLITE_STATUS_MALLOC_SIZE 5
5177
#define SQLITE_STATUS_PARSER_STACK 6
5178
#define SQLITE_STATUS_PAGECACHE_SIZE 7
5179
#define SQLITE_STATUS_SCRATCH_SIZE 8
5182
** CAPI3REF: Database Connection Status {H17500} <S60200>
5185
** This interface is used to retrieve runtime status information
5186
** about a single [database connection]. The first argument is the
5187
** database connection object to be interrogated. The second argument
5188
** is the parameter to interrogate. Currently, the only allowed value
5189
** for the second parameter is [SQLITE_DBSTATUS_LOOKASIDE_USED].
5190
** Additional options will likely appear in future releases of SQLite.
5192
** The current value of the requested parameter is written into *pCur
5193
** and the highest instantaneous value is written into *pHiwtr. If
5194
** the resetFlg is true, then the highest instantaneous value is
5195
** reset back down to the current value.
5197
** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
5199
SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
5202
** CAPI3REF: Status Parameters for database connections {H17520} <H17500>
5205
** These constants are the available integer "verbs" that can be passed as
5206
** the second argument to the [sqlite3_db_status()] interface.
5208
** New verbs may be added in future releases of SQLite. Existing verbs
5209
** might be discontinued. Applications should check the return code from
5210
** [sqlite3_db_status()] to make sure that the call worked.
5211
** The [sqlite3_db_status()] interface will return a non-zero error code
5212
** if a discontinued or unsupported verb is invoked.
5215
** <dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
5216
** <dd>This parameter returns the number of lookaside memory slots currently
5217
** checked out.</dd>
5220
#define SQLITE_DBSTATUS_LOOKASIDE_USED 0
5224
** CAPI3REF: Prepared Statement Status {H17550} <S60200>
5227
** Each prepared statement maintains various
5228
** [SQLITE_STMTSTATUS_SORT | counters] that measure the number
5229
** of times it has performed specific operations. These counters can
5230
** be used to monitor the performance characteristics of the prepared
5231
** statements. For example, if the number of table steps greatly exceeds
5232
** the number of table searches or result rows, that would tend to indicate
5233
** that the prepared statement is using a full table scan rather than
5236
** This interface is used to retrieve and reset counter values from
5237
** a [prepared statement]. The first argument is the prepared statement
5238
** object to be interrogated. The second argument
5239
** is an integer code for a specific [SQLITE_STMTSTATUS_SORT | counter]
5240
** to be interrogated.
5241
** The current value of the requested counter is returned.
5242
** If the resetFlg is true, then the counter is reset to zero after this
5243
** interface call returns.
5245
** See also: [sqlite3_status()] and [sqlite3_db_status()].
5247
SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
5250
** CAPI3REF: Status Parameters for prepared statements {H17570} <H17550>
5253
** These preprocessor macros define integer codes that name counter
5254
** values associated with the [sqlite3_stmt_status()] interface.
5255
** The meanings of the various counters are as follows:
5258
** <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
5259
** <dd>This is the number of times that SQLite has stepped forward in
5260
** a table as part of a full table scan. Large numbers for this counter
5261
** may indicate opportunities for performance improvement through
5262
** careful use of indices.</dd>
5264
** <dt>SQLITE_STMTSTATUS_SORT</dt>
5265
** <dd>This is the number of sort operations that have occurred.
5266
** A non-zero value in this counter may indicate an opportunity to
5267
** improvement performance through careful use of indices.</dd>
5271
#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1
5272
#define SQLITE_STMTSTATUS_SORT 2
5275
** CAPI3REF: Custom Page Cache Object
5278
** The sqlite3_pcache type is opaque. It is implemented by
5279
** the pluggable module. The SQLite core has no knowledge of
5280
** its size or internal structure and never deals with the
5281
** sqlite3_pcache object except by holding and passing pointers
5284
** See [sqlite3_pcache_methods] for additional information.
5286
typedef struct sqlite3_pcache sqlite3_pcache;
5289
** CAPI3REF: Application Defined Page Cache.
5290
** KEYWORDS: {page cache}
5293
** The [sqlite3_config]([SQLITE_CONFIG_PCACHE], ...) interface can
5294
** register an alternative page cache implementation by passing in an
5295
** instance of the sqlite3_pcache_methods structure. The majority of the
5296
** heap memory used by SQLite is used by the page cache to cache data read
5297
** from, or ready to be written to, the database file. By implementing a
5298
** custom page cache using this API, an application can control more
5299
** precisely the amount of memory consumed by SQLite, the way in which
5300
** that memory is allocated and released, and the policies used to
5301
** determine exactly which parts of a database file are cached and for
5304
** The contents of the sqlite3_pcache_methods structure are copied to an
5305
** internal buffer by SQLite within the call to [sqlite3_config]. Hence
5306
** the application may discard the parameter after the call to
5307
** [sqlite3_config()] returns.
5309
** The xInit() method is called once for each call to [sqlite3_initialize()]
5310
** (usually only once during the lifetime of the process). It is passed
5311
** a copy of the sqlite3_pcache_methods.pArg value. It can be used to set
5312
** up global structures and mutexes required by the custom page cache
5315
** The xShutdown() method is called from within [sqlite3_shutdown()],
5316
** if the application invokes this API. It can be used to clean up
5317
** any outstanding resources before process shutdown, if required.
5319
** SQLite holds a [SQLITE_MUTEX_RECURSIVE] mutex when it invokes
5320
** the xInit method, so the xInit method need not be threadsafe. The
5321
** xShutdown method is only called from [sqlite3_shutdown()] so it does
5322
** not need to be threadsafe either. All other methods must be threadsafe
5323
** in multithreaded applications.
5325
** SQLite will never invoke xInit() more than once without an intervening
5326
** call to xShutdown().
5328
** The xCreate() method is used to construct a new cache instance. SQLite
5329
** will typically create one cache instance for each open database file,
5330
** though this is not guaranteed. The
5331
** first parameter, szPage, is the size in bytes of the pages that must
5332
** be allocated by the cache. szPage will not be a power of two. szPage
5333
** will the page size of the database file that is to be cached plus an
5334
** increment (here called "R") of about 100 or 200. SQLite will use the
5335
** extra R bytes on each page to store metadata about the underlying
5336
** database page on disk. The value of R depends
5337
** on the SQLite version, the target platform, and how SQLite was compiled.
5338
** R is constant for a particular build of SQLite. The second argument to
5339
** xCreate(), bPurgeable, is true if the cache being created will
5340
** be used to cache database pages of a file stored on disk, or
5341
** false if it is used for an in-memory database. The cache implementation
5342
** does not have to do anything special based with the value of bPurgeable;
5343
** it is purely advisory. On a cache where bPurgeable is false, SQLite will
5344
** never invoke xUnpin() except to deliberately delete a page.
5345
** In other words, a cache created with bPurgeable set to false will
5346
** never contain any unpinned pages.
5348
** The xCachesize() method may be called at any time by SQLite to set the
5349
** suggested maximum cache-size (number of pages stored by) the cache
5350
** instance passed as the first argument. This is the value configured using
5351
** the SQLite "[PRAGMA cache_size]" command. As with the bPurgeable parameter,
5352
** the implementation is not required to do anything with this
5353
** value; it is advisory only.
5355
** The xPagecount() method should return the number of pages currently
5356
** stored in the cache.
5358
** The xFetch() method is used to fetch a page and return a pointer to it.
5359
** A 'page', in this context, is a buffer of szPage bytes aligned at an
5360
** 8-byte boundary. The page to be fetched is determined by the key. The
5361
** mimimum key value is 1. After it has been retrieved using xFetch, the page
5362
** is considered to be "pinned".
5364
** If the requested page is already in the page cache, then the page cache
5365
** implementation must return a pointer to the page buffer with its content
5366
** intact. If the requested page is not already in the cache, then the
5367
** behavior of the cache implementation is determined by the value of the
5368
** createFlag parameter passed to xFetch, according to the following table:
5370
** <table border=1 width=85% align=center>
5371
** <tr><th> createFlag <th> Behaviour when page is not already in cache
5372
** <tr><td> 0 <td> Do not allocate a new page. Return NULL.
5373
** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
5374
** Otherwise return NULL.
5375
** <tr><td> 2 <td> Make every effort to allocate a new page. Only return
5376
** NULL if allocating a new page is effectively impossible.
5379
** SQLite will normally invoke xFetch() with a createFlag of 0 or 1. If
5380
** a call to xFetch() with createFlag==1 returns NULL, then SQLite will
5381
** attempt to unpin one or more cache pages by spilling the content of
5382
** pinned pages to disk and synching the operating system disk cache. After
5383
** attempting to unpin pages, the xFetch() method will be invoked again with
5384
** a createFlag of 2.
5386
** xUnpin() is called by SQLite with a pointer to a currently pinned page
5387
** as its second argument. If the third parameter, discard, is non-zero,
5388
** then the page should be evicted from the cache. In this case SQLite
5389
** assumes that the next time the page is retrieved from the cache using
5390
** the xFetch() method, it will be zeroed. If the discard parameter is
5391
** zero, then the page is considered to be unpinned. The cache implementation
5392
** may choose to evict unpinned pages at any time.
5394
** The cache is not required to perform any reference counting. A single
5395
** call to xUnpin() unpins the page regardless of the number of prior calls
5398
** The xRekey() method is used to change the key value associated with the
5399
** page passed as the second argument from oldKey to newKey. If the cache
5400
** previously contains an entry associated with newKey, it should be
5401
** discarded. Any prior cache entry associated with newKey is guaranteed not
5404
** When SQLite calls the xTruncate() method, the cache must discard all
5405
** existing cache entries with page numbers (keys) greater than or equal
5406
** to the value of the iLimit parameter passed to xTruncate(). If any
5407
** of these pages are pinned, they are implicitly unpinned, meaning that
5408
** they can be safely discarded.
5410
** The xDestroy() method is used to delete a cache allocated by xCreate().
5411
** All resources associated with the specified cache should be freed. After
5412
** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
5413
** handle invalid, and will not use it with any other sqlite3_pcache_methods
5416
typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
5417
struct sqlite3_pcache_methods {
5419
int (*xInit)(void*);
5420
void (*xShutdown)(void*);
5421
sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
5422
void (*xCachesize)(sqlite3_pcache*, int nCachesize);
5423
int (*xPagecount)(sqlite3_pcache*);
5424
void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
5425
void (*xUnpin)(sqlite3_pcache*, void*, int discard);
5426
void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
5427
void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
5428
void (*xDestroy)(sqlite3_pcache*);
5432
** CAPI3REF: Online Backup Object
5435
** The sqlite3_backup object records state information about an ongoing
5436
** online backup operation. The sqlite3_backup object is created by
5437
** a call to [sqlite3_backup_init()] and is destroyed by a call to
5438
** [sqlite3_backup_finish()].
5440
** See Also: [Using the SQLite Online Backup API]
5442
typedef struct sqlite3_backup sqlite3_backup;
5445
** CAPI3REF: Online Backup API.
5448
** This API is used to overwrite the contents of one database with that
5449
** of another. It is useful either for creating backups of databases or
5450
** for copying in-memory databases to or from persistent files.
5452
** See Also: [Using the SQLite Online Backup API]
5454
** Exclusive access is required to the destination database for the
5455
** duration of the operation. However the source database is only
5456
** read-locked while it is actually being read, it is not locked
5457
** continuously for the entire operation. Thus, the backup may be
5458
** performed on a live database without preventing other users from
5459
** writing to the database for an extended period of time.
5461
** To perform a backup operation:
5463
** <li><b>sqlite3_backup_init()</b> is called once to initialize the
5465
** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
5466
** the data between the two databases, and finally
5467
** <li><b>sqlite3_backup_finish()</b> is called to release all resources
5468
** associated with the backup operation.
5470
** There should be exactly one call to sqlite3_backup_finish() for each
5471
** successful call to sqlite3_backup_init().
5473
** <b>sqlite3_backup_init()</b>
5475
** The first two arguments passed to [sqlite3_backup_init()] are the database
5476
** handle associated with the destination database and the database name
5477
** used to attach the destination database to the handle. The database name
5478
** is "main" for the main database, "temp" for the temporary database, or
5479
** the name specified as part of the [ATTACH] statement if the destination is
5480
** an attached database. The third and fourth arguments passed to
5481
** sqlite3_backup_init() identify the [database connection]
5482
** and database name used
5483
** to access the source database. The values passed for the source and
5484
** destination [database connection] parameters must not be the same.
5486
** If an error occurs within sqlite3_backup_init(), then NULL is returned
5487
** and an error code and error message written into the [database connection]
5488
** passed as the first argument. They may be retrieved using the
5489
** [sqlite3_errcode()], [sqlite3_errmsg()], and [sqlite3_errmsg16()] functions.
5490
** Otherwise, if successful, a pointer to an [sqlite3_backup] object is
5491
** returned. This pointer may be used with the sqlite3_backup_step() and
5492
** sqlite3_backup_finish() functions to perform the specified backup
5495
** <b>sqlite3_backup_step()</b>
5497
** Function [sqlite3_backup_step()] is used to copy up to nPage pages between
5498
** the source and destination databases, where nPage is the value of the
5499
** second parameter passed to sqlite3_backup_step(). If nPage is a negative
5500
** value, all remaining source pages are copied. If the required pages are
5501
** successfully copied, but there are still more pages to copy before the
5502
** backup is complete, it returns [SQLITE_OK]. If no error occured and there
5503
** are no more pages to copy, then [SQLITE_DONE] is returned. If an error
5504
** occurs, then an SQLite error code is returned. As well as [SQLITE_OK] and
5505
** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
5506
** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
5507
** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
5509
** As well as the case where the destination database file was opened for
5510
** read-only access, sqlite3_backup_step() may return [SQLITE_READONLY] if
5511
** the destination is an in-memory database with a different page size
5512
** from the source database.
5514
** If sqlite3_backup_step() cannot obtain a required file-system lock, then
5515
** the [sqlite3_busy_handler | busy-handler function]
5516
** is invoked (if one is specified). If the
5517
** busy-handler returns non-zero before the lock is available, then
5518
** [SQLITE_BUSY] is returned to the caller. In this case the call to
5519
** sqlite3_backup_step() can be retried later. If the source
5520
** [database connection]
5521
** is being used to write to the source database when sqlite3_backup_step()
5522
** is called, then [SQLITE_LOCKED] is returned immediately. Again, in this
5523
** case the call to sqlite3_backup_step() can be retried later on. If
5524
** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
5525
** [SQLITE_READONLY] is returned, then
5526
** there is no point in retrying the call to sqlite3_backup_step(). These
5527
** errors are considered fatal. At this point the application must accept
5528
** that the backup operation has failed and pass the backup operation handle
5529
** to the sqlite3_backup_finish() to release associated resources.
5531
** Following the first call to sqlite3_backup_step(), an exclusive lock is
5532
** obtained on the destination file. It is not released until either
5533
** sqlite3_backup_finish() is called or the backup operation is complete
5534
** and sqlite3_backup_step() returns [SQLITE_DONE]. Additionally, each time
5535
** a call to sqlite3_backup_step() is made a [shared lock] is obtained on
5536
** the source database file. This lock is released before the
5537
** sqlite3_backup_step() call returns. Because the source database is not
5538
** locked between calls to sqlite3_backup_step(), it may be modified mid-way
5539
** through the backup procedure. If the source database is modified by an
5540
** external process or via a database connection other than the one being
5541
** used by the backup operation, then the backup will be transparently
5542
** restarted by the next call to sqlite3_backup_step(). If the source
5543
** database is modified by the using the same database connection as is used
5544
** by the backup operation, then the backup database is transparently
5545
** updated at the same time.
5547
** <b>sqlite3_backup_finish()</b>
5549
** Once sqlite3_backup_step() has returned [SQLITE_DONE], or when the
5550
** application wishes to abandon the backup operation, the [sqlite3_backup]
5551
** object should be passed to sqlite3_backup_finish(). This releases all
5552
** resources associated with the backup operation. If sqlite3_backup_step()
5553
** has not yet returned [SQLITE_DONE], then any active write-transaction on the
5554
** destination database is rolled back. The [sqlite3_backup] object is invalid
5555
** and may not be used following a call to sqlite3_backup_finish().
5557
** The value returned by sqlite3_backup_finish is [SQLITE_OK] if no error
5558
** occurred, regardless or whether or not sqlite3_backup_step() was called
5559
** a sufficient number of times to complete the backup operation. Or, if
5560
** an out-of-memory condition or IO error occured during a call to
5561
** sqlite3_backup_step() then [SQLITE_NOMEM] or an
5562
** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] error code
5563
** is returned. In this case the error code and an error message are
5564
** written to the destination [database connection].
5566
** A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() is
5567
** not a permanent error and does not affect the return value of
5568
** sqlite3_backup_finish().
5570
** <b>sqlite3_backup_remaining(), sqlite3_backup_pagecount()</b>
5572
** Each call to sqlite3_backup_step() sets two values stored internally
5573
** by an [sqlite3_backup] object. The number of pages still to be backed
5574
** up, which may be queried by sqlite3_backup_remaining(), and the total
5575
** number of pages in the source database file, which may be queried by
5576
** sqlite3_backup_pagecount().
5578
** The values returned by these functions are only updated by
5579
** sqlite3_backup_step(). If the source database is modified during a backup
5580
** operation, then the values are not updated to account for any extra
5581
** pages that need to be updated or the size of the source database file
5584
** <b>Concurrent Usage of Database Handles</b>
5586
** The source [database connection] may be used by the application for other
5587
** purposes while a backup operation is underway or being initialized.
5588
** If SQLite is compiled and configured to support threadsafe database
5589
** connections, then the source database connection may be used concurrently
5590
** from within other threads.
5592
** However, the application must guarantee that the destination database
5593
** connection handle is not passed to any other API (by any thread) after
5594
** sqlite3_backup_init() is called and before the corresponding call to
5595
** sqlite3_backup_finish(). Unfortunately SQLite does not currently check
5596
** for this, if the application does use the destination [database connection]
5597
** for some other purpose during a backup operation, things may appear to
5598
** work correctly but in fact be subtly malfunctioning. Use of the
5599
** destination database connection while a backup is in progress might
5600
** also cause a mutex deadlock.
5602
** Furthermore, if running in [shared cache mode], the application must
5603
** guarantee that the shared cache used by the destination database
5604
** is not accessed while the backup is running. In practice this means
5605
** that the application must guarantee that the file-system file being
5606
** backed up to is not accessed by any connection within the process,
5607
** not just the specific connection that was passed to sqlite3_backup_init().
5609
** The [sqlite3_backup] object itself is partially threadsafe. Multiple
5610
** threads may safely make multiple concurrent calls to sqlite3_backup_step().
5611
** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
5612
** APIs are not strictly speaking threadsafe. If they are invoked at the
5613
** same time as another thread is invoking sqlite3_backup_step() it is
5614
** possible that they return invalid values.
5616
SQLITE_API sqlite3_backup *sqlite3_backup_init(
5617
sqlite3 *pDest, /* Destination database handle */
5618
const char *zDestName, /* Destination database name */
5619
sqlite3 *pSource, /* Source database handle */
5620
const char *zSourceName /* Source database name */
5622
SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage);
5623
SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p);
5624
SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p);
5625
SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p);
5628
** CAPI3REF: Unlock Notification
5631
** When running in shared-cache mode, a database operation may fail with
5632
** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
5633
** individual tables within the shared-cache cannot be obtained. See
5634
** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
5635
** This API may be used to register a callback that SQLite will invoke
5636
** when the connection currently holding the required lock relinquishes it.
5637
** This API is only available if the library was compiled with the
5638
** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
5640
** See Also: [Using the SQLite Unlock Notification Feature].
5642
** Shared-cache locks are released when a database connection concludes
5643
** its current transaction, either by committing it or rolling it back.
5645
** When a connection (known as the blocked connection) fails to obtain a
5646
** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
5647
** identity of the database connection (the blocking connection) that
5648
** has locked the required resource is stored internally. After an
5649
** application receives an SQLITE_LOCKED error, it may call the
5650
** sqlite3_unlock_notify() method with the blocked connection handle as
5651
** the first argument to register for a callback that will be invoked
5652
** when the blocking connections current transaction is concluded. The
5653
** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
5654
** call that concludes the blocking connections transaction.
5656
** If sqlite3_unlock_notify() is called in a multi-threaded application,
5657
** there is a chance that the blocking connection will have already
5658
** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
5659
** If this happens, then the specified callback is invoked immediately,
5660
** from within the call to sqlite3_unlock_notify().
5662
** If the blocked connection is attempting to obtain a write-lock on a
5663
** shared-cache table, and more than one other connection currently holds
5664
** a read-lock on the same table, then SQLite arbitrarily selects one of
5665
** the other connections to use as the blocking connection.
5667
** There may be at most one unlock-notify callback registered by a
5668
** blocked connection. If sqlite3_unlock_notify() is called when the
5669
** blocked connection already has a registered unlock-notify callback,
5670
** then the new callback replaces the old. If sqlite3_unlock_notify() is
5671
** called with a NULL pointer as its second argument, then any existing
5672
** unlock-notify callback is cancelled. The blocked connections
5673
** unlock-notify callback may also be canceled by closing the blocked
5674
** connection using [sqlite3_close()].
5676
** The unlock-notify callback is not reentrant. If an application invokes
5677
** any sqlite3_xxx API functions from within an unlock-notify callback, a
5678
** crash or deadlock may be the result.
5680
** Unless deadlock is detected (see below), sqlite3_unlock_notify() always
5681
** returns SQLITE_OK.
5683
** <b>Callback Invocation Details</b>
5685
** When an unlock-notify callback is registered, the application provides a
5686
** single void* pointer that is passed to the callback when it is invoked.
5687
** However, the signature of the callback function allows SQLite to pass
5688
** it an array of void* context pointers. The first argument passed to
5689
** an unlock-notify callback is a pointer to an array of void* pointers,
5690
** and the second is the number of entries in the array.
5692
** When a blocking connections transaction is concluded, there may be
5693
** more than one blocked connection that has registered for an unlock-notify
5694
** callback. If two or more such blocked connections have specified the
5695
** same callback function, then instead of invoking the callback function
5696
** multiple times, it is invoked once with the set of void* context pointers
5697
** specified by the blocked connections bundled together into an array.
5698
** This gives the application an opportunity to prioritize any actions
5699
** related to the set of unblocked database connections.
5701
** <b>Deadlock Detection</b>
5703
** Assuming that after registering for an unlock-notify callback a
5704
** database waits for the callback to be issued before taking any further
5705
** action (a reasonable assumption), then using this API may cause the
5706
** application to deadlock. For example, if connection X is waiting for
5707
** connection Y's transaction to be concluded, and similarly connection
5708
** Y is waiting on connection X's transaction, then neither connection
5709
** will proceed and the system may remain deadlocked indefinitely.
5711
** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
5712
** detection. If a given call to sqlite3_unlock_notify() would put the
5713
** system in a deadlocked state, then SQLITE_LOCKED is returned and no
5714
** unlock-notify callback is registered. The system is said to be in
5715
** a deadlocked state if connection A has registered for an unlock-notify
5716
** callback on the conclusion of connection B's transaction, and connection
5717
** B has itself registered for an unlock-notify callback when connection
5718
** A's transaction is concluded. Indirect deadlock is also detected, so
5719
** the system is also considered to be deadlocked if connection B has
5720
** registered for an unlock-notify callback on the conclusion of connection
5721
** C's transaction, where connection C is waiting on connection A. Any
5722
** number of levels of indirection are allowed.
5724
** <b>The "DROP TABLE" Exception</b>
5726
** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost
5727
** always appropriate to call sqlite3_unlock_notify(). There is however,
5728
** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
5729
** SQLite checks if there are any currently executing SELECT statements
5730
** that belong to the same connection. If there are, SQLITE_LOCKED is
5731
** returned. In this case there is no "blocking connection", so invoking
5732
** sqlite3_unlock_notify() results in the unlock-notify callback being
5733
** invoked immediately. If the application then re-attempts the "DROP TABLE"
5734
** or "DROP INDEX" query, an infinite loop might be the result.
5736
** One way around this problem is to check the extended error code returned
5737
** by an sqlite3_step() call. If there is a blocking connection, then the
5738
** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
5739
** the special "DROP TABLE/INDEX" case, the extended error code is just
5742
SQLITE_API int sqlite3_unlock_notify(
5743
sqlite3 *pBlocked, /* Waiting connection */
5744
void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */
5745
void *pNotifyArg /* Argument to pass to xNotify */
5750
** CAPI3REF: String Comparison
5753
** The [sqlite3_strnicmp()] API allows applications and extensions to
5754
** compare the contents of two buffers containing UTF-8 strings in a
5755
** case-indendent fashion, using the same definition of case independence
5756
** that SQLite uses internally when comparing identifiers.
5758
SQLITE_API int sqlite3_strnicmp(const char *, const char *, int);
5761
** Undo the hack that converts floating point types to integer for
5762
** builds on processors without floating point support.
5764
#ifdef SQLITE_OMIT_FLOATING_POINT
5769
} /* End of the 'extern "C"' block */
added
removed
src/core/spatialite/headers/spatialite/sqlite3.h
