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1 /*
2 ** 2001 September 15
3 **
4 ** The author disclaims copyright to this source code. In place of
5 ** a legal notice, here is a blessing:
6 **
7 ** May you do good and not evil.
8 ** May you find forgiveness for yourself and forgive others.
9 ** May you share freely, never taking more than you give.
10 **
11 *************************************************************************
12 ** This header file defines the interface that the SQLite library
13 ** presents to client programs. If a C-function, structure, datatype,
14 ** or constant definition does not appear in this file, then it is
15 ** not a published API of SQLite, is subject to change without
16 ** notice, and should not be referenced by programs that use SQLite.
17 **
18 ** Some of the definitions that are in this file are marked as
19 ** "experimental". Experimental interfaces are normally new
20 ** features recently added to SQLite. We do not anticipate changes
21 ** to experimental interfaces but reserve the right to make minor changes
22 ** if experience from use "in the wild" suggest such changes are prudent.
23 **
24 ** The official C-language API documentation for SQLite is derived
25 ** from comments in this file. This file is the authoritative source
26 ** on how SQLite interfaces are suppose to operate.
27 **
28 ** The name of this file under configuration management is "sqlite.h.in".
29 ** The makefile makes some minor changes to this file (such as inserting
30 ** the version number) and changes its name to "sqlite3.h" as
31 ** part of the build process.
32 */
33 #ifndef _SQLITE3_H_
34 #define _SQLITE3_H_
37 /*
38 ** Make sure we can call this stuff from C++.
39 */
40 #ifdef __cplusplus
42 #endif
45 /*
46 ** Add the ability to override 'extern'
47 */
48 #ifndef SQLITE_EXTERN
49 # define SQLITE_EXTERN extern
50 #endif
52 #ifndef SQLITE_API
53 # define SQLITE_API
54 #endif
57 /*
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.
63 **
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
68 ** noop macros.
69 */
70 #define SQLITE_DEPRECATED
71 #define SQLITE_EXPERIMENTAL
73 /*
74 ** Ensure these symbols were not defined by some previous header file.
75 */
76 #ifdef SQLITE_VERSION
77 # undef SQLITE_VERSION
78 #endif
79 #ifdef SQLITE_VERSION_NUMBER
80 # undef SQLITE_VERSION_NUMBER
81 #endif
83 /*
84 ** CAPI3REF: Compile-Time Library Version Numbers
85 **
86 ** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header
87 ** evaluates to a string literal that is the SQLite version in the
88 ** format "X.Y.Z" where X is the major version number (always 3 for
89 ** SQLite3) and Y is the minor version number and Z is the release number.)^
90 ** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer
91 ** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same
92 ** numbers used in [SQLITE_VERSION].)^
93 ** The SQLITE_VERSION_NUMBER for any given release of SQLite will also
94 ** be larger than the release from which it is derived. Either Y will
95 ** be held constant and Z will be incremented or else Y will be incremented
96 ** and Z will be reset to zero.
97 **
98 ** Since version 3.6.18, SQLite source code has been stored in the
99 ** <a href="http://www.fossil-scm.org/">Fossil configuration management
100 ** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to
101 ** a string which identifies a particular check-in of SQLite
102 ** within its configuration management system. ^The SQLITE_SOURCE_ID
103 ** string contains the date and time of the check-in (UTC) and an SHA1
104 ** hash of the entire source tree.
105 **
106 ** See also: [sqlite3_libversion()],
107 ** [sqlite3_libversion_number()], [sqlite3_sourceid()],
108 ** [sqlite_version()] and [sqlite_source_id()].
109 */
111 #define SQLITE_VERSION_NUMBER 3007006
114 /*
115 ** CAPI3REF: Run-Time Library Version Numbers
116 ** KEYWORDS: sqlite3_version, sqlite3_sourceid
117 **
118 ** These interfaces provide the same information as the [SQLITE_VERSION],
119 ** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros
120 ** but are associated with the library instead of the header file. ^(Cautious
121 ** programmers might include assert() statements in their application to
122 ** verify that values returned by these interfaces match the macros in
123 ** the header, and thus insure that the application is
124 ** compiled with matching library and header files.
125 **
126 ** <blockquote><pre>
127 ** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
128 ** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 );
129 ** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
130 ** </pre></blockquote>)^
131 **
132 ** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION]
133 ** macro. ^The sqlite3_libversion() function returns a pointer to the
134 ** to the sqlite3_version[] string constant. The sqlite3_libversion()
135 ** function is provided for use in DLLs since DLL users usually do not have
136 ** direct access to string constants within the DLL. ^The
137 ** sqlite3_libversion_number() function returns an integer equal to
138 ** [SQLITE_VERSION_NUMBER]. ^The sqlite3_sourceid() function returns
139 ** a pointer to a string constant whose value is the same as the
140 ** [SQLITE_SOURCE_ID] C preprocessor macro.
141 **
142 ** See also: [sqlite_version()] and [sqlite_source_id()].
143 */
149 /*
150 ** CAPI3REF: Run-Time Library Compilation Options Diagnostics
151 **
152 ** ^The sqlite3_compileoption_used() function returns 0 or 1
153 ** indicating whether the specified option was defined at
154 ** compile time. ^The SQLITE_ prefix may be omitted from the
155 ** option name passed to sqlite3_compileoption_used().
156 **
157 ** ^The sqlite3_compileoption_get() function allows iterating
158 ** over the list of options that were defined at compile time by
159 ** returning the N-th compile time option string. ^If N is out of range,
160 ** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_
161 ** prefix is omitted from any strings returned by
162 ** sqlite3_compileoption_get().
163 **
164 ** ^Support for the diagnostic functions sqlite3_compileoption_used()
165 ** and sqlite3_compileoption_get() may be omitted by specifying the
166 ** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time.
167 **
168 ** See also: SQL functions [sqlite_compileoption_used()] and
169 ** [sqlite_compileoption_get()] and the [compile_options pragma].
170 */
171 #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
174 #endif
176 /*
177 ** CAPI3REF: Test To See If The Library Is Threadsafe
178 **
179 ** ^The sqlite3_threadsafe() function returns zero if and only if
180 ** SQLite was compiled mutexing code omitted due to the
181 ** [SQLITE_THREADSAFE] compile-time option being set to 0.
182 **
183 ** SQLite can be compiled with or without mutexes. When
184 ** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
185 ** are enabled and SQLite is threadsafe. When the
186 ** [SQLITE_THREADSAFE] macro is 0,
187 ** the mutexes are omitted. Without the mutexes, it is not safe
188 ** to use SQLite concurrently from more than one thread.
189 **
190 ** Enabling mutexes incurs a measurable performance penalty.
191 ** So if speed is of utmost importance, it makes sense to disable
192 ** the mutexes. But for maximum safety, mutexes should be enabled.
193 ** ^The default behavior is for mutexes to be enabled.
194 **
195 ** This interface can be used by an application to make sure that the
196 ** version of SQLite that it is linking against was compiled with
197 ** the desired setting of the [SQLITE_THREADSAFE] macro.
198 **
199 ** This interface only reports on the compile-time mutex setting
200 ** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with
201 ** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
202 ** can be fully or partially disabled using a call to [sqlite3_config()]
203 ** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD],
204 ** or [SQLITE_CONFIG_MUTEX]. ^(The return value of the
205 ** sqlite3_threadsafe() function shows only the compile-time setting of
206 ** thread safety, not any run-time changes to that setting made by
207 ** sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
208 ** is unchanged by calls to sqlite3_config().)^
209 **
210 ** See the [threading mode] documentation for additional information.
211 */
214 /*
215 ** CAPI3REF: Database Connection Handle
216 ** KEYWORDS: {database connection} {database connections}
217 **
218 ** Each open SQLite database is represented by a pointer to an instance of
219 ** the opaque structure named "sqlite3". It is useful to think of an sqlite3
220 ** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and
221 ** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
222 ** is its destructor. There are many other interfaces (such as
223 ** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
224 ** [sqlite3_busy_timeout()] to name but three) that are methods on an
225 ** sqlite3 object.
226 */
229 /*
230 ** CAPI3REF: 64-Bit Integer Types
231 ** KEYWORDS: sqlite_int64 sqlite_uint64
232 **
233 ** Because there is no cross-platform way to specify 64-bit integer types
234 ** SQLite includes typedefs for 64-bit signed and unsigned integers.
235 **
236 ** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
237 ** The sqlite_int64 and sqlite_uint64 types are supported for backwards
238 ** compatibility only.
239 **
240 ** ^The sqlite3_int64 and sqlite_int64 types can store integer values
241 ** between -9223372036854775808 and +9223372036854775807 inclusive. ^The
242 ** sqlite3_uint64 and sqlite_uint64 types can store integer values
243 ** between 0 and +18446744073709551615 inclusive.
244 */
245 #ifdef SQLITE_INT64_TYPE
248 #elif defined(_MSC_VER) || defined(__BORLANDC__)
251 #else
254 #endif
258 /*
259 ** If compiling for a processor that lacks floating point support,
260 ** substitute integer for floating-point.
261 */
262 #ifdef SQLITE_OMIT_FLOATING_POINT
263 # define double sqlite3_int64
264 #endif
266 /*
267 ** CAPI3REF: Closing A Database Connection
268 **
269 ** ^The sqlite3_close() routine is the destructor for the [sqlite3] object.
270 ** ^Calls to sqlite3_close() return SQLITE_OK if the [sqlite3] object is
271 ** successfully destroyed and all associated resources are deallocated.
272 **
273 ** Applications must [sqlite3_finalize | finalize] all [prepared statements]
274 ** and [sqlite3_blob_close | close] all [BLOB handles] associated with
275 ** the [sqlite3] object prior to attempting to close the object. ^If
276 ** sqlite3_close() is called on a [database connection] that still has
277 ** outstanding [prepared statements] or [BLOB handles], then it returns
278 ** SQLITE_BUSY.
279 **
280 ** ^If [sqlite3_close()] is invoked while a transaction is open,
281 ** the transaction is automatically rolled back.
282 **
283 ** The C parameter to [sqlite3_close(C)] must be either a NULL
284 ** pointer or an [sqlite3] object pointer obtained
285 ** from [sqlite3_open()], [sqlite3_open16()], or
286 ** [sqlite3_open_v2()], and not previously closed.
287 ** ^Calling sqlite3_close() with a NULL pointer argument is a
288 ** harmless no-op.
289 */
292 /*
293 ** The type for a callback function.
294 ** This is legacy and deprecated. It is included for historical
295 ** compatibility and is not documented.
296 */
299 /*
300 ** CAPI3REF: One-Step Query Execution Interface
301 **
302 ** The sqlite3_exec() interface is a convenience wrapper around
303 ** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
304 ** that allows an application to run multiple statements of SQL
305 ** without having to use a lot of C code.
306 **
307 ** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
308 ** semicolon-separate SQL statements passed into its 2nd argument,
309 ** in the context of the [database connection] passed in as its 1st
310 ** argument. ^If the callback function of the 3rd argument to
311 ** sqlite3_exec() is not NULL, then it is invoked for each result row
312 ** coming out of the evaluated SQL statements. ^The 4th argument to
313 ** to sqlite3_exec() is relayed through to the 1st argument of each
314 ** callback invocation. ^If the callback pointer to sqlite3_exec()
315 ** is NULL, then no callback is ever invoked and result rows are
316 ** ignored.
317 **
318 ** ^If an error occurs while evaluating the SQL statements passed into
319 ** sqlite3_exec(), then execution of the current statement stops and
320 ** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec()
321 ** is not NULL then any error message is written into memory obtained
322 ** from [sqlite3_malloc()] and passed back through the 5th parameter.
323 ** To avoid memory leaks, the application should invoke [sqlite3_free()]
324 ** on error message strings returned through the 5th parameter of
325 ** of sqlite3_exec() after the error message string is no longer needed.
326 ** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
327 ** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
328 ** NULL before returning.
329 **
330 ** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
331 ** routine returns SQLITE_ABORT without invoking the callback again and
332 ** without running any subsequent SQL statements.
333 **
334 ** ^The 2nd argument to the sqlite3_exec() callback function is the
335 ** number of columns in the result. ^The 3rd argument to the sqlite3_exec()
336 ** callback is an array of pointers to strings obtained as if from
337 ** [sqlite3_column_text()], one for each column. ^If an element of a
338 ** result row is NULL then the corresponding string pointer for the
339 ** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the
340 ** sqlite3_exec() callback is an array of pointers to strings where each
341 ** entry represents the name of corresponding result column as obtained
342 ** from [sqlite3_column_name()].
343 **
344 ** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
345 ** to an empty string, or a pointer that contains only whitespace and/or
346 ** SQL comments, then no SQL statements are evaluated and the database
347 ** is not changed.
348 **
349 ** Restrictions:
350 **
351 ** <ul>
352 ** <li> The application must insure that the 1st parameter to sqlite3_exec()
353 ** is a valid and open [database connection].
354 ** <li> The application must not close [database connection] specified by
355 ** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
356 ** <li> The application must not modify the SQL statement text passed into
357 ** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
358 ** </ul>
359 */
366 );
368 /*
369 ** CAPI3REF: Result Codes
370 ** KEYWORDS: SQLITE_OK {error code} {error codes}
371 ** KEYWORDS: {result code} {result codes}
372 **
373 ** Many SQLite functions return an integer result code from the set shown
374 ** here in order to indicates success or failure.
375 **
376 ** New error codes may be added in future versions of SQLite.
377 **
378 ** See also: [SQLITE_IOERR_READ | extended result codes]
379 */
381 /* beginning-of-error-codes */
410 /* end-of-error-codes */
412 /*
413 ** CAPI3REF: Extended Result Codes
414 ** KEYWORDS: {extended error code} {extended error codes}
415 ** KEYWORDS: {extended result code} {extended result codes}
416 **
417 ** In its default configuration, SQLite API routines return one of 26 integer
418 ** [SQLITE_OK | result codes]. However, experience has shown that many of
419 ** these result codes are too coarse-grained. They do not provide as
420 ** much information about problems as programmers might like. In an effort to
421 ** address this, newer versions of SQLite (version 3.3.8 and later) include
422 ** support for additional result codes that provide more detailed information
423 ** about errors. The extended result codes are enabled or disabled
424 ** on a per database connection basis using the
425 ** [sqlite3_extended_result_codes()] API.
426 **
427 ** Some of the available extended result codes are listed here.
428 ** One may expect the number of extended result codes will be expand
429 ** over time. Software that uses extended result codes should expect
430 ** to see new result codes in future releases of SQLite.
431 **
432 ** The SQLITE_OK result code will never be extended. It will always
433 ** be exactly zero.
434 */
435 #define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8))
436 #define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8))
437 #define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8))
438 #define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8))
439 #define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8))
440 #define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8))
441 #define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8))
442 #define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8))
443 #define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8))
444 #define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8))
445 #define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8))
446 #define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8))
447 #define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8))
448 #define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
449 #define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8))
450 #define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8))
451 #define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8))
452 #define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8))
453 #define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8))
454 #define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8))
455 #define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8))
456 #define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8))
457 #define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8))
459 /*
460 ** CAPI3REF: Flags For File Open Operations
461 **
462 ** These bit values are intended for use in the
463 ** 3rd parameter to the [sqlite3_open_v2()] interface and
464 ** in the 4th parameter to the xOpen method of the
465 ** [sqlite3_vfs] object.
466 */
486 /* Reserved: 0x00F00000 */
488 /*
489 ** CAPI3REF: Device Characteristics
490 **
491 ** The xDeviceCharacteristics method of the [sqlite3_io_methods]
492 ** object returns an integer which is a vector of the these
493 ** bit values expressing I/O characteristics of the mass storage
494 ** device that holds the file that the [sqlite3_io_methods]
495 ** refers to.
496 **
497 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
498 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
499 ** mean that writes of blocks that are nnn bytes in size and
500 ** are aligned to an address which is an integer multiple of
501 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
502 ** that when data is appended to a file, the data is appended
503 ** first then the size of the file is extended, never the other
504 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
505 ** information is written to disk in the same order as calls
506 ** to xWrite().
507 */
508 #define SQLITE_IOCAP_ATOMIC 0x00000001
509 #define SQLITE_IOCAP_ATOMIC512 0x00000002
510 #define SQLITE_IOCAP_ATOMIC1K 0x00000004
511 #define SQLITE_IOCAP_ATOMIC2K 0x00000008
512 #define SQLITE_IOCAP_ATOMIC4K 0x00000010
513 #define SQLITE_IOCAP_ATOMIC8K 0x00000020
514 #define SQLITE_IOCAP_ATOMIC16K 0x00000040
515 #define SQLITE_IOCAP_ATOMIC32K 0x00000080
516 #define SQLITE_IOCAP_ATOMIC64K 0x00000100
517 #define SQLITE_IOCAP_SAFE_APPEND 0x00000200
518 #define SQLITE_IOCAP_SEQUENTIAL 0x00000400
519 #define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800
521 /*
522 ** CAPI3REF: File Locking Levels
523 **
524 ** SQLite uses one of these integer values as the second
525 ** argument to calls it makes to the xLock() and xUnlock() methods
526 ** of an [sqlite3_io_methods] object.
527 */
528 #define SQLITE_LOCK_NONE 0
529 #define SQLITE_LOCK_SHARED 1
530 #define SQLITE_LOCK_RESERVED 2
531 #define SQLITE_LOCK_PENDING 3
532 #define SQLITE_LOCK_EXCLUSIVE 4
534 /*
535 ** CAPI3REF: Synchronization Type Flags
536 **
537 ** When SQLite invokes the xSync() method of an
538 ** [sqlite3_io_methods] object it uses a combination of
539 ** these integer values as the second argument.
540 **
541 ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
542 ** sync operation only needs to flush data to mass storage. Inode
543 ** information need not be flushed. If the lower four bits of the flag
544 ** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
545 ** If the lower four bits equal SQLITE_SYNC_FULL, that means
546 ** to use Mac OS X style fullsync instead of fsync().
547 **
548 ** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
549 ** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
550 ** settings. The [synchronous pragma] determines when calls to the
551 ** xSync VFS method occur and applies uniformly across all platforms.
552 ** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
553 ** energetic or rigorous or forceful the sync operations are and
554 ** only make a difference on Mac OSX for the default SQLite code.
555 ** (Third-party VFS implementations might also make the distinction
556 ** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
557 ** operating systems natively supported by SQLite, only Mac OSX
558 ** cares about the difference.)
559 */
560 #define SQLITE_SYNC_NORMAL 0x00002
561 #define SQLITE_SYNC_FULL 0x00003
562 #define SQLITE_SYNC_DATAONLY 0x00010
564 /*
565 ** CAPI3REF: OS Interface Open File Handle
566 **
567 ** An [sqlite3_file] object represents an open file in the
568 ** [sqlite3_vfs | OS interface layer]. Individual OS interface
569 ** implementations will
570 ** want to subclass this object by appending additional fields
571 ** for their own use. The pMethods entry is a pointer to an
572 ** [sqlite3_io_methods] object that defines methods for performing
573 ** I/O operations on the open file.
574 */
578 };
580 /*
581 ** CAPI3REF: OS Interface File Virtual Methods Object
582 **
583 ** Every file opened by the [sqlite3_vfs] xOpen method populates an
584 ** [sqlite3_file] object (or, more commonly, a subclass of the
585 ** [sqlite3_file] object) with a pointer to an instance of this object.
586 ** This object defines the methods used to perform various operations
587 ** against the open file represented by the [sqlite3_file] object.
588 **
589 ** If the xOpen method sets the sqlite3_file.pMethods element
590 ** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
591 ** may be invoked even if the xOpen reported that it failed. The
592 ** only way to prevent a call to xClose following a failed xOpen
593 ** is for the xOpen to set the sqlite3_file.pMethods element to NULL.
594 **
595 ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
596 ** [SQLITE_SYNC_FULL]. The first choice is the normal fsync().
597 ** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY]
598 ** flag may be ORed in to indicate that only the data of the file
599 ** and not its inode needs to be synced.
600 **
601 ** The integer values to xLock() and xUnlock() are one of
602 ** <ul>
603 ** <li> [SQLITE_LOCK_NONE],
604 ** <li> [SQLITE_LOCK_SHARED],
605 ** <li> [SQLITE_LOCK_RESERVED],
606 ** <li> [SQLITE_LOCK_PENDING], or
607 ** <li> [SQLITE_LOCK_EXCLUSIVE].
608 ** </ul>
609 ** xLock() increases the lock. xUnlock() decreases the lock.
610 ** The xCheckReservedLock() method checks whether any database connection,
611 ** either in this process or in some other process, is holding a RESERVED,
612 ** PENDING, or EXCLUSIVE lock on the file. It returns true
613 ** if such a lock exists and false otherwise.
614 **
615 ** The xFileControl() method is a generic interface that allows custom
616 ** VFS implementations to directly control an open file using the
617 ** [sqlite3_file_control()] interface. The second "op" argument is an
618 ** integer opcode. The third argument is a generic pointer intended to
619 ** point to a structure that may contain arguments or space in which to
620 ** write return values. Potential uses for xFileControl() might be
621 ** functions to enable blocking locks with timeouts, to change the
622 ** locking strategy (for example to use dot-file locks), to inquire
623 ** about the status of a lock, or to break stale locks. The SQLite
624 ** core reserves all opcodes less than 100 for its own use.
625 ** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available.
626 ** Applications that define a custom xFileControl method should use opcodes
627 ** greater than 100 to avoid conflicts. VFS implementations should
628 ** return [SQLITE_NOTFOUND] for file control opcodes that they do not
629 ** recognize.
630 **
631 ** The xSectorSize() method returns the sector size of the
632 ** device that underlies the file. The sector size is the
633 ** minimum write that can be performed without disturbing
634 ** other bytes in the file. The xDeviceCharacteristics()
635 ** method returns a bit vector describing behaviors of the
636 ** underlying device:
637 **
638 ** <ul>
639 ** <li> [SQLITE_IOCAP_ATOMIC]
640 ** <li> [SQLITE_IOCAP_ATOMIC512]
641 ** <li> [SQLITE_IOCAP_ATOMIC1K]
642 ** <li> [SQLITE_IOCAP_ATOMIC2K]
643 ** <li> [SQLITE_IOCAP_ATOMIC4K]
644 ** <li> [SQLITE_IOCAP_ATOMIC8K]
645 ** <li> [SQLITE_IOCAP_ATOMIC16K]
646 ** <li> [SQLITE_IOCAP_ATOMIC32K]
647 ** <li> [SQLITE_IOCAP_ATOMIC64K]
648 ** <li> [SQLITE_IOCAP_SAFE_APPEND]
649 ** <li> [SQLITE_IOCAP_SEQUENTIAL]
650 ** </ul>
651 **
652 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
653 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
654 ** mean that writes of blocks that are nnn bytes in size and
655 ** are aligned to an address which is an integer multiple of
656 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
657 ** that when data is appended to a file, the data is appended
658 ** first then the size of the file is extended, never the other
659 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
660 ** information is written to disk in the same order as calls
661 ** to xWrite().
662 **
663 ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
664 ** in the unread portions of the buffer with zeros. A VFS that
665 ** fails to zero-fill short reads might seem to work. However,
666 ** failure to zero-fill short reads will eventually lead to
667 ** database corruption.
668 */
684 /* Methods above are valid for version 1 */
689 /* Methods above are valid for version 2 */
690 /* Additional methods may be added in future releases */
691 };
693 /*
694 ** CAPI3REF: Standard File Control Opcodes
695 **
696 ** These integer constants are opcodes for the xFileControl method
697 ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
698 ** interface.
699 **
700 ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This
701 ** opcode causes the xFileControl method to write the current state of
702 ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
703 ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
704 ** into an integer that the pArg argument points to. This capability
705 ** is used during testing and only needs to be supported when SQLITE_TEST
706 ** is defined.
707 **
708 ** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
709 ** layer a hint of how large the database file will grow to be during the
710 ** current transaction. This hint is not guaranteed to be accurate but it
711 ** is often close. The underlying VFS might choose to preallocate database
712 ** file space based on this hint in order to help writes to the database
713 ** file run faster.
714 **
715 ** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
716 ** extends and truncates the database file in chunks of a size specified
717 ** by the user. The fourth argument to [sqlite3_file_control()] should
718 ** point to an integer (type int) containing the new chunk-size to use
719 ** for the nominated database. Allocating database file space in large
720 ** chunks (say 1MB at a time), may reduce file-system fragmentation and
721 ** improve performance on some systems.
722 **
723 ** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
724 ** to the [sqlite3_file] object associated with a particular database
725 ** connection. See the [sqlite3_file_control()] documentation for
726 ** additional information.
727 **
728 ** ^(The [SQLITE_FCNTL_SYNC_OMITTED] opcode is generated internally by
729 ** SQLite and sent to all VFSes in place of a call to the xSync method
730 ** when the database connection has [PRAGMA synchronous] set to OFF.)^
731 ** Some specialized VFSes need this signal in order to operate correctly
732 ** when [PRAGMA synchronous | PRAGMA synchronous=OFF] is set, but most
733 ** VFSes do not need this signal and should silently ignore this opcode.
734 ** Applications should not call [sqlite3_file_control()] with this
735 ** opcode as doing so may disrupt the operation of the specialized VFSes
736 ** that do require it.
737 */
738 #define SQLITE_FCNTL_LOCKSTATE 1
739 #define SQLITE_GET_LOCKPROXYFILE 2
740 #define SQLITE_SET_LOCKPROXYFILE 3
741 #define SQLITE_LAST_ERRNO 4
742 #define SQLITE_FCNTL_SIZE_HINT 5
743 #define SQLITE_FCNTL_CHUNK_SIZE 6
744 #define SQLITE_FCNTL_FILE_POINTER 7
745 #define SQLITE_FCNTL_SYNC_OMITTED 8
748 /*
749 ** CAPI3REF: Mutex Handle
750 **
751 ** The mutex module within SQLite defines [sqlite3_mutex] to be an
752 ** abstract type for a mutex object. The SQLite core never looks
753 ** at the internal representation of an [sqlite3_mutex]. It only
754 ** deals with pointers to the [sqlite3_mutex] object.
755 **
756 ** Mutexes are created using [sqlite3_mutex_alloc()].
757 */
760 /*
761 ** CAPI3REF: OS Interface Object
762 **
763 ** An instance of the sqlite3_vfs object defines the interface between
764 ** the SQLite core and the underlying operating system. The "vfs"
765 ** in the name of the object stands for "virtual file system".
766 **
767 ** The value of the iVersion field is initially 1 but may be larger in
768 ** future versions of SQLite. Additional fields may be appended to this
769 ** object when the iVersion value is increased. Note that the structure
770 ** of the sqlite3_vfs object changes in the transaction between
771 ** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not
772 ** modified.
773 **
774 ** The szOsFile field is the size of the subclassed [sqlite3_file]
775 ** structure used by this VFS. mxPathname is the maximum length of
776 ** a pathname in this VFS.
777 **
778 ** Registered sqlite3_vfs objects are kept on a linked list formed by
779 ** the pNext pointer. The [sqlite3_vfs_register()]
780 ** and [sqlite3_vfs_unregister()] interfaces manage this list
781 ** in a thread-safe way. The [sqlite3_vfs_find()] interface
782 ** searches the list. Neither the application code nor the VFS
783 ** implementation should use the pNext pointer.
784 **
785 ** The pNext field is the only field in the sqlite3_vfs
786 ** structure that SQLite will ever modify. SQLite will only access
787 ** or modify this field while holding a particular static mutex.
788 ** The application should never modify anything within the sqlite3_vfs
789 ** object once the object has been registered.
790 **
791 ** The zName field holds the name of the VFS module. The name must
792 ** be unique across all VFS modules.
793 **
794 ** ^SQLite guarantees that the zFilename parameter to xOpen
795 ** is either a NULL pointer or string obtained
796 ** from xFullPathname() with an optional suffix added.
797 ** ^If a suffix is added to the zFilename parameter, it will
798 ** consist of a single "-" character followed by no more than
799 ** 10 alphanumeric and/or "-" characters.
800 ** ^SQLite further guarantees that
801 ** the string will be valid and unchanged until xClose() is
802 ** called. Because of the previous sentence,
803 ** the [sqlite3_file] can safely store a pointer to the
804 ** filename if it needs to remember the filename for some reason.
805 ** If the zFilename parameter to xOpen is a NULL pointer then xOpen
806 ** must invent its own temporary name for the file. ^Whenever the
807 ** xFilename parameter is NULL it will also be the case that the
808 ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
809 **
810 ** The flags argument to xOpen() includes all bits set in
811 ** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()]
812 ** or [sqlite3_open16()] is used, then flags includes at least
813 ** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE].
814 ** If xOpen() opens a file read-only then it sets *pOutFlags to
815 ** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set.
816 **
817 ** ^(SQLite will also add one of the following flags to the xOpen()
818 ** call, depending on the object being opened:
819 **
820 ** <ul>
821 ** <li> [SQLITE_OPEN_MAIN_DB]
822 ** <li> [SQLITE_OPEN_MAIN_JOURNAL]
823 ** <li> [SQLITE_OPEN_TEMP_DB]
824 ** <li> [SQLITE_OPEN_TEMP_JOURNAL]
825 ** <li> [SQLITE_OPEN_TRANSIENT_DB]
826 ** <li> [SQLITE_OPEN_SUBJOURNAL]
827 ** <li> [SQLITE_OPEN_MASTER_JOURNAL]
828 ** <li> [SQLITE_OPEN_WAL]
829 ** </ul>)^
830 **
831 ** The file I/O implementation can use the object type flags to
832 ** change the way it deals with files. For example, an application
833 ** that does not care about crash recovery or rollback might make
834 ** the open of a journal file a no-op. Writes to this journal would
835 ** also be no-ops, and any attempt to read the journal would return
836 ** SQLITE_IOERR. Or the implementation might recognize that a database
837 ** file will be doing page-aligned sector reads and writes in a random
838 ** order and set up its I/O subsystem accordingly.
839 **
840 ** SQLite might also add one of the following flags to the xOpen method:
841 **
842 ** <ul>
843 ** <li> [SQLITE_OPEN_DELETEONCLOSE]
844 ** <li> [SQLITE_OPEN_EXCLUSIVE]
845 ** </ul>
846 **
847 ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
848 ** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE]
849 ** will be set for TEMP databases and their journals, transient
850 ** databases, and subjournals.
851 **
852 ** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
853 ** with the [SQLITE_OPEN_CREATE] flag, which are both directly
854 ** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
855 ** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
856 ** SQLITE_OPEN_CREATE, is used to indicate that file should always
857 ** be created, and that it is an error if it already exists.
858 ** It is <i>not</i> used to indicate the file should be opened
859 ** for exclusive access.
860 **
861 ** ^At least szOsFile bytes of memory are allocated by SQLite
862 ** to hold the [sqlite3_file] structure passed as the third
863 ** argument to xOpen. The xOpen method does not have to
864 ** allocate the structure; it should just fill it in. Note that
865 ** the xOpen method must set the sqlite3_file.pMethods to either
866 ** a valid [sqlite3_io_methods] object or to NULL. xOpen must do
867 ** this even if the open fails. SQLite expects that the sqlite3_file.pMethods
868 ** element will be valid after xOpen returns regardless of the success
869 ** or failure of the xOpen call.
870 **
871 ** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
872 ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
873 ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
874 ** to test whether a file is at least readable. The file can be a
875 ** directory.
876 **
877 ** ^SQLite will always allocate at least mxPathname+1 bytes for the
878 ** output buffer xFullPathname. The exact size of the output buffer
879 ** is also passed as a parameter to both methods. If the output buffer
880 ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
881 ** handled as a fatal error by SQLite, vfs implementations should endeavor
882 ** to prevent this by setting mxPathname to a sufficiently large value.
883 **
884 ** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
885 ** interfaces are not strictly a part of the filesystem, but they are
886 ** included in the VFS structure for completeness.
887 ** The xRandomness() function attempts to return nBytes bytes
888 ** of good-quality randomness into zOut. The return value is
889 ** the actual number of bytes of randomness obtained.
890 ** The xSleep() method causes the calling thread to sleep for at
891 ** least the number of microseconds given. ^The xCurrentTime()
892 ** method returns a Julian Day Number for the current date and time as
893 ** a floating point value.
894 ** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
895 ** Day Number multipled by 86400000 (the number of milliseconds in
896 ** a 24-hour day).
897 ** ^SQLite will use the xCurrentTimeInt64() method to get the current
898 ** date and time if that method is available (if iVersion is 2 or
899 ** greater and the function pointer is not NULL) and will fall back
900 ** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
901 **
902 ** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
903 ** are not used by the SQLite core. These optional interfaces are provided
904 ** by some VFSes to facilitate testing of the VFS code. By overriding
905 ** system calls with functions under its control, a test program can
906 ** simulate faults and error conditions that would otherwise be difficult
907 ** or impossible to induce. The set of system calls that can be overridden
908 ** varies from one VFS to another, and from one version of the same VFS to the
909 ** next. Applications that use these interfaces must be prepared for any
910 ** or all of these interfaces to be NULL or for their behavior to change
911 ** from one release to the next. Applications must not attempt to access
912 ** any of these methods if the iVersion of the VFS is less than 3.
913 */
936 /*
937 ** The methods above are in version 1 of the sqlite_vfs object
938 ** definition. Those that follow are added in version 2 or later
939 */
941 /*
942 ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
943 ** Those below are for version 3 and greater.
944 */
948 /*
949 ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
950 ** New fields may be appended in figure versions. The iVersion
951 ** value will increment whenever this happens.
952 */
953 };
955 /*
956 ** CAPI3REF: Flags for the xAccess VFS method
957 **
958 ** These integer constants can be used as the third parameter to
959 ** the xAccess method of an [sqlite3_vfs] object. They determine
960 ** what kind of permissions the xAccess method is looking for.
961 ** With SQLITE_ACCESS_EXISTS, the xAccess method
962 ** simply checks whether the file exists.
963 ** With SQLITE_ACCESS_READWRITE, the xAccess method
964 ** checks whether the named directory is both readable and writable
965 ** (in other words, if files can be added, removed, and renamed within
966 ** the directory).
967 ** The SQLITE_ACCESS_READWRITE constant is currently used only by the
968 ** [temp_store_directory pragma], though this could change in a future
969 ** release of SQLite.
970 ** With SQLITE_ACCESS_READ, the xAccess method
971 ** checks whether the file is readable. The SQLITE_ACCESS_READ constant is
972 ** currently unused, though it might be used in a future release of
973 ** SQLite.
974 */
975 #define SQLITE_ACCESS_EXISTS 0
979 /*
980 ** CAPI3REF: Flags for the xShmLock VFS method
981 **
982 ** These integer constants define the various locking operations
983 ** allowed by the xShmLock method of [sqlite3_io_methods]. The
984 ** following are the only legal combinations of flags to the
985 ** xShmLock method:
986 **
987 ** <ul>
988 ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
989 ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
990 ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
991 ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
992 ** </ul>
993 **
994 ** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
995 ** was given no the corresponding lock.
996 **
997 ** The xShmLock method can transition between unlocked and SHARED or
998 ** between unlocked and EXCLUSIVE. It cannot transition between SHARED
999 ** and EXCLUSIVE.
1000 */
1001 #define SQLITE_SHM_UNLOCK 1
1002 #define SQLITE_SHM_LOCK 2
1003 #define SQLITE_SHM_SHARED 4
1004 #define SQLITE_SHM_EXCLUSIVE 8
1006 /*
1007 ** CAPI3REF: Maximum xShmLock index
1008 **
1009 ** The xShmLock method on [sqlite3_io_methods] may use values
1010 ** between 0 and this upper bound as its "offset" argument.
1011 ** The SQLite core will never attempt to acquire or release a
1012 ** lock outside of this range
1013 */
1014 #define SQLITE_SHM_NLOCK 8
1017 /*
1018 ** CAPI3REF: Initialize The SQLite Library
1019 **
1020 ** ^The sqlite3_initialize() routine initializes the
1021 ** SQLite library. ^The sqlite3_shutdown() routine
1022 ** deallocates any resources that were allocated by sqlite3_initialize().
1023 ** These routines are designed to aid in process initialization and
1024 ** shutdown on embedded systems. Workstation applications using
1025 ** SQLite normally do not need to invoke either of these routines.
1026 **
1027 ** A call to sqlite3_initialize() is an "effective" call if it is
1028 ** the first time sqlite3_initialize() is invoked during the lifetime of
1029 ** the process, or if it is the first time sqlite3_initialize() is invoked
1030 ** following a call to sqlite3_shutdown(). ^(Only an effective call
1031 ** of sqlite3_initialize() does any initialization. All other calls
1032 ** are harmless no-ops.)^
1033 **
1034 ** A call to sqlite3_shutdown() is an "effective" call if it is the first
1035 ** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only
1036 ** an effective call to sqlite3_shutdown() does any deinitialization.
1037 ** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
1038 **
1039 ** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
1040 ** is not. The sqlite3_shutdown() interface must only be called from a
1041 ** single thread. All open [database connections] must be closed and all
1042 ** other SQLite resources must be deallocated prior to invoking
1043 ** sqlite3_shutdown().
1044 **
1045 ** Among other things, ^sqlite3_initialize() will invoke
1046 ** sqlite3_os_init(). Similarly, ^sqlite3_shutdown()
1047 ** will invoke sqlite3_os_end().
1048 **
1049 ** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
1050 ** ^If for some reason, sqlite3_initialize() is unable to initialize
1051 ** the library (perhaps it is unable to allocate a needed resource such
1052 ** as a mutex) it returns an [error code] other than [SQLITE_OK].
1053 **
1054 ** ^The sqlite3_initialize() routine is called internally by many other
1055 ** SQLite interfaces so that an application usually does not need to
1056 ** invoke sqlite3_initialize() directly. For example, [sqlite3_open()]
1057 ** calls sqlite3_initialize() so the SQLite library will be automatically
1058 ** initialized when [sqlite3_open()] is called if it has not be initialized
1059 ** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
1060 ** compile-time option, then the automatic calls to sqlite3_initialize()
1061 ** are omitted and the application must call sqlite3_initialize() directly
1062 ** prior to using any other SQLite interface. For maximum portability,
1063 ** it is recommended that applications always invoke sqlite3_initialize()
1064 ** directly prior to using any other SQLite interface. Future releases
1065 ** of SQLite may require this. In other words, the behavior exhibited
1066 ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
1067 ** default behavior in some future release of SQLite.
1068 **
1069 ** The sqlite3_os_init() routine does operating-system specific
1070 ** initialization of the SQLite library. The sqlite3_os_end()
1071 ** routine undoes the effect of sqlite3_os_init(). Typical tasks
1072 ** performed by these routines include allocation or deallocation
1073 ** of static resources, initialization of global variables,
1074 ** setting up a default [sqlite3_vfs] module, or setting up
1075 ** a default configuration using [sqlite3_config()].
1076 **
1077 ** The application should never invoke either sqlite3_os_init()
1078 ** or sqlite3_os_end() directly. The application should only invoke
1079 ** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init()
1080 ** interface is called automatically by sqlite3_initialize() and
1081 ** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate
1082 ** implementations for sqlite3_os_init() and sqlite3_os_end()
1083 ** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
1084 ** When [custom builds | built for other platforms]
1085 ** (using the [SQLITE_OS_OTHER=1] compile-time
1086 ** option) the application must supply a suitable implementation for
1087 ** sqlite3_os_init() and sqlite3_os_end(). An application-supplied
1088 ** implementation of sqlite3_os_init() or sqlite3_os_end()
1089 ** must return [SQLITE_OK] on success and some other [error code] upon
1090 ** failure.
1091 */
1097 /*
1098 ** CAPI3REF: Configuring The SQLite Library
1099 **
1100 ** The sqlite3_config() interface is used to make global configuration
1101 ** changes to SQLite in order to tune SQLite to the specific needs of
1102 ** the application. The default configuration is recommended for most
1103 ** applications and so this routine is usually not necessary. It is
1104 ** provided to support rare applications with unusual needs.
1105 **
1106 ** The sqlite3_config() interface is not threadsafe. The application
1107 ** must insure that no other SQLite interfaces are invoked by other
1108 ** threads while sqlite3_config() is running. Furthermore, sqlite3_config()
1109 ** may only be invoked prior to library initialization using
1110 ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
1111 ** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
1112 ** [sqlite3_shutdown()] then it will return SQLITE_MISUSE.
1113 ** Note, however, that ^sqlite3_config() can be called as part of the
1114 ** implementation of an application-defined [sqlite3_os_init()].
1115 **
1116 ** The first argument to sqlite3_config() is an integer
1117 ** [SQLITE_CONFIG_SINGLETHREAD | configuration option] that determines
1118 ** what property of SQLite is to be configured. Subsequent arguments
1119 ** vary depending on the [SQLITE_CONFIG_SINGLETHREAD | configuration option]
1120 ** in the first argument.
1121 **
1122 ** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
1123 ** ^If the option is unknown or SQLite is unable to set the option
1124 ** then this routine returns a non-zero [error code].
1125 */
1128 /*
1129 ** CAPI3REF: Configure database connections
1130 **
1131 ** The sqlite3_db_config() interface is used to make configuration
1132 ** changes to a [database connection]. The interface is similar to
1133 ** [sqlite3_config()] except that the changes apply to a single
1134 ** [database connection] (specified in the first argument).
1135 **
1136 ** The second argument to sqlite3_db_config(D,V,...) is the
1137 ** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code
1138 ** that indicates what aspect of the [database connection] is being configured.
1139 ** Subsequent arguments vary depending on the configuration verb.
1140 **
1141 ** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
1142 ** the call is considered successful.
1143 */
1146 /*
1147 ** CAPI3REF: Memory Allocation Routines
1148 **
1149 ** An instance of this object defines the interface between SQLite
1150 ** and low-level memory allocation routines.
1151 **
1152 ** This object is used in only one place in the SQLite interface.
1153 ** A pointer to an instance of this object is the argument to
1154 ** [sqlite3_config()] when the configuration option is
1155 ** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].
1156 ** By creating an instance of this object
1157 ** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
1158 ** during configuration, an application can specify an alternative
1159 ** memory allocation subsystem for SQLite to use for all of its
1160 ** dynamic memory needs.
1161 **
1162 ** Note that SQLite comes with several [built-in memory allocators]
1163 ** that are perfectly adequate for the overwhelming majority of applications
1164 ** and that this object is only useful to a tiny minority of applications
1165 ** with specialized memory allocation requirements. This object is
1166 ** also used during testing of SQLite in order to specify an alternative
1167 ** memory allocator that simulates memory out-of-memory conditions in
1168 ** order to verify that SQLite recovers gracefully from such
1169 ** conditions.
1170 **
1171 ** The xMalloc and xFree methods must work like the
1172 ** malloc() and free() functions from the standard C library.
1173 ** The xRealloc method must work like realloc() from the standard C library
1174 ** with the exception that if the second argument to xRealloc is zero,
1175 ** xRealloc must be a no-op - it must not perform any allocation or
1176 ** deallocation. ^SQLite guarantees that the second argument to
1177 ** xRealloc is always a value returned by a prior call to xRoundup.
1178 ** And so in cases where xRoundup always returns a positive number,
1179 ** xRealloc can perform exactly as the standard library realloc() and
1180 ** still be in compliance with this specification.
1181 **
1182 ** xSize should return the allocated size of a memory allocation
1183 ** previously obtained from xMalloc or xRealloc. The allocated size
1184 ** is always at least as big as the requested size but may be larger.
1185 **
1186 ** The xRoundup method returns what would be the allocated size of
1187 ** a memory allocation given a particular requested size. Most memory
1188 ** allocators round up memory allocations at least to the next multiple
1189 ** of 8. Some allocators round up to a larger multiple or to a power of 2.
1190 ** Every memory allocation request coming in through [sqlite3_malloc()]
1191 ** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0,
1192 ** that causes the corresponding memory allocation to fail.
1193 **
1194 ** The xInit method initializes the memory allocator. (For example,
1195 ** it might allocate any require mutexes or initialize internal data
1196 ** structures. The xShutdown method is invoked (indirectly) by
1197 ** [sqlite3_shutdown()] and should deallocate any resources acquired
1198 ** by xInit. The pAppData pointer is used as the only parameter to
1199 ** xInit and xShutdown.
1200 **
1201 ** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes
1202 ** the xInit method, so the xInit method need not be threadsafe. The
1203 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
1204 ** not need to be threadsafe either. For all other methods, SQLite
1205 ** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
1206 ** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
1207 ** it is by default) and so the methods are automatically serialized.
1208 ** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
1209 ** methods must be threadsafe or else make their own arrangements for
1210 ** serialization.
1211 **
1212 ** SQLite will never invoke xInit() more than once without an intervening
1213 ** call to xShutdown().
1214 */
1225 };
1227 /*
1228 ** CAPI3REF: Configuration Options
1229 **
1230 ** These constants are the available integer configuration options that
1231 ** can be passed as the first argument to the [sqlite3_config()] interface.
1232 **
1233 ** New configuration options may be added in future releases of SQLite.
1234 ** Existing configuration options might be discontinued. Applications
1235 ** should check the return code from [sqlite3_config()] to make sure that
1236 ** the call worked. The [sqlite3_config()] interface will return a
1237 ** non-zero [error code] if a discontinued or unsupported configuration option
1238 ** is invoked.
1239 **
1240 ** <dl>
1241 ** <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
1242 ** <dd>There are no arguments to this option. ^This option sets the
1243 ** [threading mode] to Single-thread. In other words, it disables
1244 ** all mutexing and puts SQLite into a mode where it can only be used
1245 ** by a single thread. ^If SQLite is compiled with
1246 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1247 ** it is not possible to change the [threading mode] from its default
1248 ** value of Single-thread and so [sqlite3_config()] will return
1249 ** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
1250 ** configuration option.</dd>
1251 **
1252 ** <dt>SQLITE_CONFIG_MULTITHREAD</dt>
1253 ** <dd>There are no arguments to this option. ^This option sets the
1254 ** [threading mode] to Multi-thread. In other words, it disables
1255 ** mutexing on [database connection] and [prepared statement] objects.
1256 ** The application is responsible for serializing access to
1257 ** [database connections] and [prepared statements]. But other mutexes
1258 ** are enabled so that SQLite will be safe to use in a multi-threaded
1259 ** environment as long as no two threads attempt to use the same
1260 ** [database connection] at the same time. ^If SQLite is compiled with
1261 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1262 ** it is not possible to set the Multi-thread [threading mode] and
1263 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1264 ** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
1265 **
1266 ** <dt>SQLITE_CONFIG_SERIALIZED</dt>
1267 ** <dd>There are no arguments to this option. ^This option sets the
1268 ** [threading mode] to Serialized. In other words, this option enables
1269 ** all mutexes including the recursive
1270 ** mutexes on [database connection] and [prepared statement] objects.
1271 ** In this mode (which is the default when SQLite is compiled with
1272 ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
1273 ** to [database connections] and [prepared statements] so that the
1274 ** application is free to use the same [database connection] or the
1275 ** same [prepared statement] in different threads at the same time.
1276 ** ^If SQLite is compiled with
1277 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1278 ** it is not possible to set the Serialized [threading mode] and
1279 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1280 ** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
1281 **
1282 ** <dt>SQLITE_CONFIG_MALLOC</dt>
1283 ** <dd> ^(This option takes a single argument which is a pointer to an
1284 ** instance of the [sqlite3_mem_methods] structure. The argument specifies
1285 ** alternative low-level memory allocation routines to be used in place of
1286 ** the memory allocation routines built into SQLite.)^ ^SQLite makes
1287 ** its own private copy of the content of the [sqlite3_mem_methods] structure
1288 ** before the [sqlite3_config()] call returns.</dd>
1289 **
1290 ** <dt>SQLITE_CONFIG_GETMALLOC</dt>
1291 ** <dd> ^(This option takes a single argument which is a pointer to an
1292 ** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods]
1293 ** structure is filled with the currently defined memory allocation routines.)^
1294 ** This option can be used to overload the default memory allocation
1295 ** routines with a wrapper that simulations memory allocation failure or
1296 ** tracks memory usage, for example. </dd>
1297 **
1298 ** <dt>SQLITE_CONFIG_MEMSTATUS</dt>
1299 ** <dd> ^This option takes single argument of type int, interpreted as a
1300 ** boolean, which enables or disables the collection of memory allocation
1301 ** statistics. ^(When memory allocation statistics are disabled, the
1302 ** following SQLite interfaces become non-operational:
1303 ** <ul>
1304 ** <li> [sqlite3_memory_used()]
1305 ** <li> [sqlite3_memory_highwater()]
1306 ** <li> [sqlite3_soft_heap_limit64()]
1307 ** <li> [sqlite3_status()]
1308 ** </ul>)^
1309 ** ^Memory allocation statistics are enabled by default unless SQLite is
1310 ** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
1311 ** allocation statistics are disabled by default.
1312 ** </dd>
1313 **
1314 ** <dt>SQLITE_CONFIG_SCRATCH</dt>
1315 ** <dd> ^This option specifies a static memory buffer that SQLite can use for
1316 ** scratch memory. There are three arguments: A pointer an 8-byte
1317 ** aligned memory buffer from which the scratch allocations will be
1318 ** drawn, the size of each scratch allocation (sz),
1319 ** and the maximum number of scratch allocations (N). The sz
1320 ** argument must be a multiple of 16.
1321 ** The first argument must be a pointer to an 8-byte aligned buffer
1322 ** of at least sz*N bytes of memory.
1323 ** ^SQLite will use no more than two scratch buffers per thread. So
1324 ** N should be set to twice the expected maximum number of threads.
1325 ** ^SQLite will never require a scratch buffer that is more than 6
1326 ** times the database page size. ^If SQLite needs needs additional
1327 ** scratch memory beyond what is provided by this configuration option, then
1328 ** [sqlite3_malloc()] will be used to obtain the memory needed.</dd>
1329 **
1330 ** <dt>SQLITE_CONFIG_PAGECACHE</dt>
1331 ** <dd> ^This option specifies a static memory buffer that SQLite can use for
1332 ** the database page cache with the default page cache implemenation.
1333 ** This configuration should not be used if an application-define page
1334 ** cache implementation is loaded using the SQLITE_CONFIG_PCACHE option.
1335 ** There are three arguments to this option: A pointer to 8-byte aligned
1336 ** memory, the size of each page buffer (sz), and the number of pages (N).
1337 ** The sz argument should be the size of the largest database page
1338 ** (a power of two between 512 and 32768) plus a little extra for each
1339 ** page header. ^The page header size is 20 to 40 bytes depending on
1340 ** the host architecture. ^It is harmless, apart from the wasted memory,
1341 ** to make sz a little too large. The first
1342 ** argument should point to an allocation of at least sz*N bytes of memory.
1343 ** ^SQLite will use the memory provided by the first argument to satisfy its
1344 ** memory needs for the first N pages that it adds to cache. ^If additional
1345 ** page cache memory is needed beyond what is provided by this option, then
1346 ** SQLite goes to [sqlite3_malloc()] for the additional storage space.
1347 ** The pointer in the first argument must
1348 ** be aligned to an 8-byte boundary or subsequent behavior of SQLite
1349 ** will be undefined.</dd>
1350 **
1351 ** <dt>SQLITE_CONFIG_HEAP</dt>
1352 ** <dd> ^This option specifies a static memory buffer that SQLite will use
1353 ** for all of its dynamic memory allocation needs beyond those provided
1354 ** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE].
1355 ** There are three arguments: An 8-byte aligned pointer to the memory,
1356 ** the number of bytes in the memory buffer, and the minimum allocation size.
1357 ** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
1358 ** to using its default memory allocator (the system malloc() implementation),
1359 ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the
1360 ** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or
1361 ** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory
1362 ** allocator is engaged to handle all of SQLites memory allocation needs.
1363 ** The first pointer (the memory pointer) must be aligned to an 8-byte
1364 ** boundary or subsequent behavior of SQLite will be undefined.
1365 ** The minimum allocation size is capped at 2^12. Reasonable values
1366 ** for the minimum allocation size are 2^5 through 2^8.</dd>
1367 **
1368 ** <dt>SQLITE_CONFIG_MUTEX</dt>
1369 ** <dd> ^(This option takes a single argument which is a pointer to an
1370 ** instance of the [sqlite3_mutex_methods] structure. The argument specifies
1371 ** alternative low-level mutex routines to be used in place
1372 ** the mutex routines built into SQLite.)^ ^SQLite makes a copy of the
1373 ** content of the [sqlite3_mutex_methods] structure before the call to
1374 ** [sqlite3_config()] returns. ^If SQLite is compiled with
1375 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1376 ** the entire mutexing subsystem is omitted from the build and hence calls to
1377 ** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
1378 ** return [SQLITE_ERROR].</dd>
1379 **
1380 ** <dt>SQLITE_CONFIG_GETMUTEX</dt>
1381 ** <dd> ^(This option takes a single argument which is a pointer to an
1382 ** instance of the [sqlite3_mutex_methods] structure. The
1383 ** [sqlite3_mutex_methods]
1384 ** structure is filled with the currently defined mutex routines.)^
1385 ** This option can be used to overload the default mutex allocation
1386 ** routines with a wrapper used to track mutex usage for performance
1387 ** profiling or testing, for example. ^If SQLite is compiled with
1388 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1389 ** the entire mutexing subsystem is omitted from the build and hence calls to
1390 ** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
1391 ** return [SQLITE_ERROR].</dd>
1392 **
1393 ** <dt>SQLITE_CONFIG_LOOKASIDE</dt>
1394 ** <dd> ^(This option takes two arguments that determine the default
1395 ** memory allocation for the lookaside memory allocator on each
1396 ** [database connection]. The first argument is the
1397 ** size of each lookaside buffer slot and the second is the number of
1398 ** slots allocated to each database connection.)^ ^(This option sets the
1399 ** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
1400 ** verb to [sqlite3_db_config()] can be used to change the lookaside
1401 ** configuration on individual connections.)^ </dd>
1402 **
1403 ** <dt>SQLITE_CONFIG_PCACHE</dt>
1404 ** <dd> ^(This option takes a single argument which is a pointer to
1405 ** an [sqlite3_pcache_methods] object. This object specifies the interface
1406 ** to a custom page cache implementation.)^ ^SQLite makes a copy of the
1407 ** object and uses it for page cache memory allocations.</dd>
1408 **
1409 ** <dt>SQLITE_CONFIG_GETPCACHE</dt>
1410 ** <dd> ^(This option takes a single argument which is a pointer to an
1411 ** [sqlite3_pcache_methods] object. SQLite copies of the current
1412 ** page cache implementation into that object.)^ </dd>
1413 **
1414 ** <dt>SQLITE_CONFIG_LOG</dt>
1415 ** <dd> ^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
1416 ** function with a call signature of void(*)(void*,int,const char*),
1417 ** and a pointer to void. ^If the function pointer is not NULL, it is
1418 ** invoked by [sqlite3_log()] to process each logging event. ^If the
1419 ** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
1420 ** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
1421 ** passed through as the first parameter to the application-defined logger
1422 ** function whenever that function is invoked. ^The second parameter to
1423 ** the logger function is a copy of the first parameter to the corresponding
1424 ** [sqlite3_log()] call and is intended to be a [result code] or an
1425 ** [extended result code]. ^The third parameter passed to the logger is
1426 ** log message after formatting via [sqlite3_snprintf()].
1427 ** The SQLite logging interface is not reentrant; the logger function
1428 ** supplied by the application must not invoke any SQLite interface.
1429 ** In a multi-threaded application, the application-defined logger
1430 ** function must be threadsafe. </dd>
1431 **
1432 ** </dl>
1433 */
1445 /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */
1451 /*
1452 ** CAPI3REF: Database Connection Configuration Options
1453 **
1454 ** These constants are the available integer configuration options that
1455 ** can be passed as the second argument to the [sqlite3_db_config()] interface.
1456 **
1457 ** New configuration options may be added in future releases of SQLite.
1458 ** Existing configuration options might be discontinued. Applications
1459 ** should check the return code from [sqlite3_db_config()] to make sure that
1460 ** the call worked. ^The [sqlite3_db_config()] interface will return a
1461 ** non-zero [error code] if a discontinued or unsupported configuration option
1462 ** is invoked.
1463 **
1464 ** <dl>
1465 ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
1466 ** <dd> ^This option takes three additional arguments that determine the
1467 ** [lookaside memory allocator] configuration for the [database connection].
1468 ** ^The first argument (the third parameter to [sqlite3_db_config()] is a
1469 ** pointer to a memory buffer to use for lookaside memory.
1470 ** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
1471 ** may be NULL in which case SQLite will allocate the
1472 ** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
1473 ** size of each lookaside buffer slot. ^The third argument is the number of
1474 ** slots. The size of the buffer in the first argument must be greater than
1475 ** or equal to the product of the second and third arguments. The buffer
1476 ** must be aligned to an 8-byte boundary. ^If the second argument to
1477 ** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
1478 ** rounded down to the next smaller multiple of 8. ^(The lookaside memory
1479 ** configuration for a database connection can only be changed when that
1480 ** connection is not currently using lookaside memory, or in other words
1481 ** when the "current value" returned by
1482 ** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero.
1483 ** Any attempt to change the lookaside memory configuration when lookaside
1484 ** memory is in use leaves the configuration unchanged and returns
1485 ** [SQLITE_BUSY].)^</dd>
1486 **
1487 ** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
1488 ** <dd> ^This option is used to enable or disable the enforcement of
1489 ** [foreign key constraints]. There should be two additional arguments.
1490 ** The first argument is an integer which is 0 to disable FK enforcement,
1491 ** positive to enable FK enforcement or negative to leave FK enforcement
1492 ** unchanged. The second parameter is a pointer to an integer into which
1493 ** is written 0 or 1 to indicate whether FK enforcement is off or on
1494 ** following this call. The second parameter may be a NULL pointer, in
1495 ** which case the FK enforcement setting is not reported back. </dd>
1496 **
1497 ** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
1498 ** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
1499 ** There should be two additional arguments.
1500 ** The first argument is an integer which is 0 to disable triggers,
1501 ** positive to enable triggers or negative to leave the setting unchanged.
1502 ** The second parameter is a pointer to an integer into which
1503 ** is written 0 or 1 to indicate whether triggers are disabled or enabled
1504 ** following this call. The second parameter may be a NULL pointer, in
1505 ** which case the trigger setting is not reported back. </dd>
1506 **
1507 ** </dl>
1508 */
1514 /*
1515 ** CAPI3REF: Enable Or Disable Extended Result Codes
1516 **
1517 ** ^The sqlite3_extended_result_codes() routine enables or disables the
1518 ** [extended result codes] feature of SQLite. ^The extended result
1519 ** codes are disabled by default for historical compatibility.
1520 */
1523 /*
1524 ** CAPI3REF: Last Insert Rowid
1525 **
1526 ** ^Each entry in an SQLite table has a unique 64-bit signed
1527 ** integer key called the [ROWID | "rowid"]. ^The rowid is always available
1528 ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
1529 ** names are not also used by explicitly declared columns. ^If
1530 ** the table has a column of type [INTEGER PRIMARY KEY] then that column
1531 ** is another alias for the rowid.
1532 **
1533 ** ^This routine returns the [rowid] of the most recent
1534 ** successful [INSERT] into the database from the [database connection]
1535 ** in the first argument. ^If no successful [INSERT]s
1536 ** have ever occurred on that database connection, zero is returned.
1537 **
1538 ** ^(If an [INSERT] occurs within a trigger, then the [rowid] of the inserted
1539 ** row is returned by this routine as long as the trigger is running.
1540 ** But once the trigger terminates, the value returned by this routine
1541 ** reverts to the last value inserted before the trigger fired.)^
1542 **
1543 ** ^An [INSERT] that fails due to a constraint violation is not a
1544 ** successful [INSERT] and does not change the value returned by this
1545 ** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
1546 ** and INSERT OR ABORT make no changes to the return value of this
1547 ** routine when their insertion fails. ^(When INSERT OR REPLACE
1548 ** encounters a constraint violation, it does not fail. The
1549 ** INSERT continues to completion after deleting rows that caused
1550 ** the constraint problem so INSERT OR REPLACE will always change
1551 ** the return value of this interface.)^
1552 **
1553 ** ^For the purposes of this routine, an [INSERT] is considered to
1554 ** be successful even if it is subsequently rolled back.
1555 **
1556 ** This function is accessible to SQL statements via the
1557 ** [last_insert_rowid() SQL function].
1558 **
1559 ** If a separate thread performs a new [INSERT] on the same
1560 ** database connection while the [sqlite3_last_insert_rowid()]
1561 ** function is running and thus changes the last insert [rowid],
1562 ** then the value returned by [sqlite3_last_insert_rowid()] is
1563 ** unpredictable and might not equal either the old or the new
1564 ** last insert [rowid].
1565 */
1568 /*
1569 ** CAPI3REF: Count The Number Of Rows Modified
1570 **
1571 ** ^This function returns the number of database rows that were changed
1572 ** or inserted or deleted by the most recently completed SQL statement
1573 ** on the [database connection] specified by the first parameter.
1574 ** ^(Only changes that are directly specified by the [INSERT], [UPDATE],
1575 ** or [DELETE] statement are counted. Auxiliary changes caused by
1576 ** triggers or [foreign key actions] are not counted.)^ Use the
1577 ** [sqlite3_total_changes()] function to find the total number of changes
1578 ** including changes caused by triggers and foreign key actions.
1579 **
1580 ** ^Changes to a view that are simulated by an [INSTEAD OF trigger]
1581 ** are not counted. Only real table changes are counted.
1582 **
1583 ** ^(A "row change" is a change to a single row of a single table
1584 ** caused by an INSERT, DELETE, or UPDATE statement. Rows that
1585 ** are changed as side effects of [REPLACE] constraint resolution,
1586 ** rollback, ABORT processing, [DROP TABLE], or by any other
1587 ** mechanisms do not count as direct row changes.)^
1588 **
1589 ** A "trigger context" is a scope of execution that begins and
1590 ** ends with the script of a [CREATE TRIGGER | trigger].
1591 ** Most SQL statements are
1592 ** evaluated outside of any trigger. This is the "top level"
1593 ** trigger context. If a trigger fires from the top level, a
1594 ** new trigger context is entered for the duration of that one
1595 ** trigger. Subtriggers create subcontexts for their duration.
1596 **
1597 ** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does
1598 ** not create a new trigger context.
1599 **
1600 ** ^This function returns the number of direct row changes in the
1601 ** most recent INSERT, UPDATE, or DELETE statement within the same
1602 ** trigger context.
1603 **
1604 ** ^Thus, when called from the top level, this function returns the
1605 ** number of changes in the most recent INSERT, UPDATE, or DELETE
1606 ** that also occurred at the top level. ^(Within the body of a trigger,
1607 ** the sqlite3_changes() interface can be called to find the number of
1608 ** changes in the most recently completed INSERT, UPDATE, or DELETE
1609 ** statement within the body of the same trigger.
1610 ** However, the number returned does not include changes
1611 ** caused by subtriggers since those have their own context.)^
1612 **
1613 ** See also the [sqlite3_total_changes()] interface, the
1614 ** [count_changes pragma], and the [changes() SQL function].
1615 **
1616 ** If a separate thread makes changes on the same database connection
1617 ** while [sqlite3_changes()] is running then the value returned
1618 ** is unpredictable and not meaningful.
1619 */
1622 /*
1623 ** CAPI3REF: Total Number Of Rows Modified
1624 **
1625 ** ^This function returns the number of row changes caused by [INSERT],
1626 ** [UPDATE] or [DELETE] statements since the [database connection] was opened.
1627 ** ^(The count returned by sqlite3_total_changes() includes all changes
1628 ** from all [CREATE TRIGGER | trigger] contexts and changes made by
1629 ** [foreign key actions]. However,
1630 ** the count does not include changes used to implement [REPLACE] constraints,
1631 ** do rollbacks or ABORT processing, or [DROP TABLE] processing. The
1632 ** count does not include rows of views that fire an [INSTEAD OF trigger],
1633 ** though if the INSTEAD OF trigger makes changes of its own, those changes
1634 ** are counted.)^
1635 ** ^The sqlite3_total_changes() function counts the changes as soon as
1636 ** the statement that makes them is completed (when the statement handle
1637 ** is passed to [sqlite3_reset()] or [sqlite3_finalize()]).
1638 **
1639 ** See also the [sqlite3_changes()] interface, the
1640 ** [count_changes pragma], and the [total_changes() SQL function].
1641 **
1642 ** If a separate thread makes changes on the same database connection
1643 ** while [sqlite3_total_changes()] is running then the value
1644 ** returned is unpredictable and not meaningful.
1645 */
1648 /*
1649 ** CAPI3REF: Interrupt A Long-Running Query
1650 **
1651 ** ^This function causes any pending database operation to abort and
1652 ** return at its earliest opportunity. This routine is typically
1653 ** called in response to a user action such as pressing "Cancel"
1654 ** or Ctrl-C where the user wants a long query operation to halt
1655 ** immediately.
1656 **
1657 ** ^It is safe to call this routine from a thread different from the
1658 ** thread that is currently running the database operation. But it
1659 ** is not safe to call this routine with a [database connection] that
1660 ** is closed or might close before sqlite3_interrupt() returns.
1661 **
1662 ** ^If an SQL operation is very nearly finished at the time when
1663 ** sqlite3_interrupt() is called, then it might not have an opportunity
1664 ** to be interrupted and might continue to completion.
1665 **
1666 ** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
1667 ** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
1668 ** that is inside an explicit transaction, then the entire transaction
1669 ** will be rolled back automatically.
1670 **
1671 ** ^The sqlite3_interrupt(D) call is in effect until all currently running
1672 ** SQL statements on [database connection] D complete. ^Any new SQL statements
1673 ** that are started after the sqlite3_interrupt() call and before the
1674 ** running statements reaches zero are interrupted as if they had been
1675 ** running prior to the sqlite3_interrupt() call. ^New SQL statements
1676 ** that are started after the running statement count reaches zero are
1677 ** not effected by the sqlite3_interrupt().
1678 ** ^A call to sqlite3_interrupt(D) that occurs when there are no running
1679 ** SQL statements is a no-op and has no effect on SQL statements
1680 ** that are started after the sqlite3_interrupt() call returns.
1681 **
1682 ** If the database connection closes while [sqlite3_interrupt()]
1683 ** is running then bad things will likely happen.
1684 */
1687 /*
1688 ** CAPI3REF: Determine If An SQL Statement Is Complete
1689 **
1690 ** These routines are useful during command-line input to determine if the
1691 ** currently entered text seems to form a complete SQL statement or
1692 ** if additional input is needed before sending the text into
1693 ** SQLite for parsing. ^These routines return 1 if the input string
1694 ** appears to be a complete SQL statement. ^A statement is judged to be
1695 ** complete if it ends with a semicolon token and is not a prefix of a
1696 ** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within
1697 ** string literals or quoted identifier names or comments are not
1698 ** independent tokens (they are part of the token in which they are
1699 ** embedded) and thus do not count as a statement terminator. ^Whitespace
1700 ** and comments that follow the final semicolon are ignored.
1701 **
1702 ** ^These routines return 0 if the statement is incomplete. ^If a
1703 ** memory allocation fails, then SQLITE_NOMEM is returned.
1704 **
1705 ** ^These routines do not parse the SQL statements thus
1706 ** will not detect syntactically incorrect SQL.
1707 **
1708 ** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior
1709 ** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
1710 ** automatically by sqlite3_complete16(). If that initialization fails,
1711 ** then the return value from sqlite3_complete16() will be non-zero
1712 ** regardless of whether or not the input SQL is complete.)^
1713 **
1714 ** The input to [sqlite3_complete()] must be a zero-terminated
1715 ** UTF-8 string.
1716 **
1717 ** The input to [sqlite3_complete16()] must be a zero-terminated
1718 ** UTF-16 string in native byte order.
1719 */
1723 /*
1724 ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
1725 **
1726 ** ^This routine sets a callback function that might be invoked whenever
1727 ** an attempt is made to open a database table that another thread
1728 ** or process has locked.
1729 **
1730 ** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]
1731 ** is returned immediately upon encountering the lock. ^If the busy callback
1732 ** is not NULL, then the callback might be invoked with two arguments.
1733 **
1734 ** ^The first argument to the busy handler is a copy of the void* pointer which
1735 ** is the third argument to sqlite3_busy_handler(). ^The second argument to
1736 ** the busy handler callback is the number of times that the busy handler has
1737 ** been invoked for this locking event. ^If the
1738 ** busy callback returns 0, then no additional attempts are made to
1739 ** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned.
1740 ** ^If the callback returns non-zero, then another attempt
1741 ** is made to open the database for reading and the cycle repeats.
1742 **
1743 ** The presence of a busy handler does not guarantee that it will be invoked
1744 ** when there is lock contention. ^If SQLite determines that invoking the busy
1745 ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
1746 ** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler.
1747 ** Consider a scenario where one process is holding a read lock that
1748 ** it is trying to promote to a reserved lock and
1749 ** a second process is holding a reserved lock that it is trying
1750 ** to promote to an exclusive lock. The first process cannot proceed
1751 ** because it is blocked by the second and the second process cannot
1752 ** proceed because it is blocked by the first. If both processes
1753 ** invoke the busy handlers, neither will make any progress. Therefore,
1754 ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
1755 ** will induce the first process to release its read lock and allow
1756 ** the second process to proceed.
1757 **
1758 ** ^The default busy callback is NULL.
1759 **
1760 ** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED]
1761 ** when SQLite is in the middle of a large transaction where all the
1762 ** changes will not fit into the in-memory cache. SQLite will
1763 ** already hold a RESERVED lock on the database file, but it needs
1764 ** to promote this lock to EXCLUSIVE so that it can spill cache
1765 ** pages into the database file without harm to concurrent
1766 ** readers. ^If it is unable to promote the lock, then the in-memory
1767 ** cache will be left in an inconsistent state and so the error
1768 ** code is promoted from the relatively benign [SQLITE_BUSY] to
1769 ** the more severe [SQLITE_IOERR_BLOCKED]. ^This error code promotion
1770 ** forces an automatic rollback of the changes. See the
1771 ** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError">
1772 ** CorruptionFollowingBusyError</a> wiki page for a discussion of why
1773 ** this is important.
1774 **
1775 ** ^(There can only be a single busy handler defined for each
1776 ** [database connection]. Setting a new busy handler clears any
1777 ** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()]
1778 ** will also set or clear the busy handler.
1779 **
1780 ** The busy callback should not take any actions which modify the
1781 ** database connection that invoked the busy handler. Any such actions
1782 ** result in undefined behavior.
1783 **
1784 ** A busy handler must not close the database connection
1785 ** or [prepared statement] that invoked the busy handler.
1786 */
1789 /*
1790 ** CAPI3REF: Set A Busy Timeout
1791 **
1792 ** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
1793 ** for a specified amount of time when a table is locked. ^The handler
1794 ** will sleep multiple times until at least "ms" milliseconds of sleeping
1795 ** have accumulated. ^After at least "ms" milliseconds of sleeping,
1796 ** the handler returns 0 which causes [sqlite3_step()] to return
1797 ** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED].
1798 **
1799 ** ^Calling this routine with an argument less than or equal to zero
1800 ** turns off all busy handlers.
1801 **
1802 ** ^(There can only be a single busy handler for a particular
1803 ** [database connection] any any given moment. If another busy handler
1804 ** was defined (using [sqlite3_busy_handler()]) prior to calling
1805 ** this routine, that other busy handler is cleared.)^
1806 */
1809 /*
1810 ** CAPI3REF: Convenience Routines For Running Queries
1811 **
1812 ** This is a legacy interface that is preserved for backwards compatibility.
1813 ** Use of this interface is not recommended.
1814 **
1815 ** Definition: A <b>result table</b> is memory data structure created by the
1816 ** [sqlite3_get_table()] interface. A result table records the
1817 ** complete query results from one or more queries.
1818 **
1819 ** The table conceptually has a number of rows and columns. But
1820 ** these numbers are not part of the result table itself. These
1821 ** numbers are obtained separately. Let N be the number of rows
1822 ** and M be the number of columns.
1823 **
1824 ** A result table is an array of pointers to zero-terminated UTF-8 strings.
1825 ** There are (N+1)*M elements in the array. The first M pointers point
1826 ** to zero-terminated strings that contain the names of the columns.
1827 ** The remaining entries all point to query results. NULL values result
1828 ** in NULL pointers. All other values are in their UTF-8 zero-terminated
1829 ** string representation as returned by [sqlite3_column_text()].
1830 **
1831 ** A result table might consist of one or more memory allocations.
1832 ** It is not safe to pass a result table directly to [sqlite3_free()].
1833 ** A result table should be deallocated using [sqlite3_free_table()].
1834 **
1835 ** ^(As an example of the result table format, suppose a query result
1836 ** is as follows:
1837 **
1838 ** <blockquote><pre>
1839 ** Name | Age
1840 ** -----------------------
1841 ** Alice | 43
1842 ** Bob | 28
1843 ** Cindy | 21
1844 ** </pre></blockquote>
1845 **
1846 ** There are two column (M==2) and three rows (N==3). Thus the
1847 ** result table has 8 entries. Suppose the result table is stored
1848 ** in an array names azResult. Then azResult holds this content:
1849 **
1850 ** <blockquote><pre>
1851 ** azResult[0] = "Name";
1852 ** azResult[1] = "Age";
1853 ** azResult[2] = "Alice";
1854 ** azResult[3] = "43";
1855 ** azResult[4] = "Bob";
1856 ** azResult[5] = "28";
1857 ** azResult[6] = "Cindy";
1858 ** azResult[7] = "21";
1859 ** </pre></blockquote>)^
1860 **
1861 ** ^The sqlite3_get_table() function evaluates one or more
1862 ** semicolon-separated SQL statements in the zero-terminated UTF-8
1863 ** string of its 2nd parameter and returns a result table to the
1864 ** pointer given in its 3rd parameter.
1865 **
1866 ** After the application has finished with the result from sqlite3_get_table(),
1867 ** it must pass the result table pointer to sqlite3_free_table() in order to
1868 ** release the memory that was malloced. Because of the way the
1869 ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
1870 ** function must not try to call [sqlite3_free()] directly. Only
1871 ** [sqlite3_free_table()] is able to release the memory properly and safely.
1872 **
1873 ** The sqlite3_get_table() interface is implemented as a wrapper around
1874 ** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access
1875 ** to any internal data structures of SQLite. It uses only the public
1876 ** interface defined here. As a consequence, errors that occur in the
1877 ** wrapper layer outside of the internal [sqlite3_exec()] call are not
1878 ** reflected in subsequent calls to [sqlite3_errcode()] or
1879 ** [sqlite3_errmsg()].
1880 */
1888 );
1891 /*
1892 ** CAPI3REF: Formatted String Printing Functions
1893 **
1894 ** These routines are work-alikes of the "printf()" family of functions
1895 ** from the standard C library.
1896 **
1897 ** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
1898 ** results into memory obtained from [sqlite3_malloc()].
1899 ** The strings returned by these two routines should be
1900 ** released by [sqlite3_free()]. ^Both routines return a
1901 ** NULL pointer if [sqlite3_malloc()] is unable to allocate enough
1902 ** memory to hold the resulting string.
1903 **
1904 ** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
1905 ** the standard C library. The result is written into the
1906 ** buffer supplied as the second parameter whose size is given by
1907 ** the first parameter. Note that the order of the
1908 ** first two parameters is reversed from snprintf().)^ This is an
1909 ** historical accident that cannot be fixed without breaking
1910 ** backwards compatibility. ^(Note also that sqlite3_snprintf()
1911 ** returns a pointer to its buffer instead of the number of
1912 ** characters actually written into the buffer.)^ We admit that
1913 ** the number of characters written would be a more useful return
1914 ** value but we cannot change the implementation of sqlite3_snprintf()
1915 ** now without breaking compatibility.
1916 **
1917 ** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
1918 ** guarantees that the buffer is always zero-terminated. ^The first
1919 ** parameter "n" is the total size of the buffer, including space for
1920 ** the zero terminator. So the longest string that can be completely
1921 ** written will be n-1 characters.
1922 **
1923 ** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
1924 **
1925 ** These routines all implement some additional formatting
1926 ** options that are useful for constructing SQL statements.
1927 ** All of the usual printf() formatting options apply. In addition, there
1928 ** is are "%q", "%Q", and "%z" options.
1929 **
1930 ** ^(The %q option works like %s in that it substitutes a null-terminated
1931 ** string from the argument list. But %q also doubles every '\'' character.
1932 ** %q is designed for use inside a string literal.)^ By doubling each '\''
1933 ** character it escapes that character and allows it to be inserted into
1934 ** the string.
1935 **
1936 ** For example, assume the string variable zText contains text as follows:
1937 **
1938 ** <blockquote><pre>
1939 ** char *zText = "It's a happy day!";
1940 ** </pre></blockquote>
1941 **
1942 ** One can use this text in an SQL statement as follows:
1943 **
1944 ** <blockquote><pre>
1945 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText);
1946 ** sqlite3_exec(db, zSQL, 0, 0, 0);
1947 ** sqlite3_free(zSQL);
1948 ** </pre></blockquote>
1949 **
1950 ** Because the %q format string is used, the '\'' character in zText
1951 ** is escaped and the SQL generated is as follows:
1952 **
1953 ** <blockquote><pre>
1954 ** INSERT INTO table1 VALUES('It''s a happy day!')
1955 ** </pre></blockquote>
1956 **
1957 ** This is correct. Had we used %s instead of %q, the generated SQL
1958 ** would have looked like this:
1959 **
1960 ** <blockquote><pre>
1961 ** INSERT INTO table1 VALUES('It's a happy day!');
1962 ** </pre></blockquote>
1963 **
1964 ** This second example is an SQL syntax error. As a general rule you should
1965 ** always use %q instead of %s when inserting text into a string literal.
1966 **
1967 ** ^(The %Q option works like %q except it also adds single quotes around
1968 ** the outside of the total string. Additionally, if the parameter in the
1969 ** argument list is a NULL pointer, %Q substitutes the text "NULL" (without
1970 ** single quotes).)^ So, for example, one could say:
1971 **
1972 ** <blockquote><pre>
1973 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText);
1974 ** sqlite3_exec(db, zSQL, 0, 0, 0);
1975 ** sqlite3_free(zSQL);
1976 ** </pre></blockquote>
1977 **
1978 ** The code above will render a correct SQL statement in the zSQL
1979 ** variable even if the zText variable is a NULL pointer.
1980 **
1981 ** ^(The "%z" formatting option works like "%s" but with the
1982 ** addition that after the string has been read and copied into
1983 ** the result, [sqlite3_free()] is called on the input string.)^
1984 */
1990 /*
1991 ** CAPI3REF: Memory Allocation Subsystem
1992 **
1993 ** The SQLite core uses these three routines for all of its own
1994 ** internal memory allocation needs. "Core" in the previous sentence
1995 ** does not include operating-system specific VFS implementation. The
1996 ** Windows VFS uses native malloc() and free() for some operations.
1997 **
1998 ** ^The sqlite3_malloc() routine returns a pointer to a block
1999 ** of memory at least N bytes in length, where N is the parameter.
2000 ** ^If sqlite3_malloc() is unable to obtain sufficient free
2001 ** memory, it returns a NULL pointer. ^If the parameter N to
2002 ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
2003 ** a NULL pointer.
2004 **
2005 ** ^Calling sqlite3_free() with a pointer previously returned
2006 ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
2007 ** that it might be reused. ^The sqlite3_free() routine is
2008 ** a no-op if is called with a NULL pointer. Passing a NULL pointer
2009 ** to sqlite3_free() is harmless. After being freed, memory
2010 ** should neither be read nor written. Even reading previously freed
2011 ** memory might result in a segmentation fault or other severe error.
2012 ** Memory corruption, a segmentation fault, or other severe error
2013 ** might result if sqlite3_free() is called with a non-NULL pointer that
2014 ** was not obtained from sqlite3_malloc() or sqlite3_realloc().
2015 **
2016 ** ^(The sqlite3_realloc() interface attempts to resize a
2017 ** prior memory allocation to be at least N bytes, where N is the
2018 ** second parameter. The memory allocation to be resized is the first
2019 ** parameter.)^ ^ If the first parameter to sqlite3_realloc()
2020 ** is a NULL pointer then its behavior is identical to calling
2021 ** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc().
2022 ** ^If the second parameter to sqlite3_realloc() is zero or
2023 ** negative then the behavior is exactly the same as calling
2024 ** sqlite3_free(P) where P is the first parameter to sqlite3_realloc().
2025 ** ^sqlite3_realloc() returns a pointer to a memory allocation
2026 ** of at least N bytes in size or NULL if sufficient memory is unavailable.
2027 ** ^If M is the size of the prior allocation, then min(N,M) bytes
2028 ** of the prior allocation are copied into the beginning of buffer returned
2029 ** by sqlite3_realloc() and the prior allocation is freed.
2030 ** ^If sqlite3_realloc() returns NULL, then the prior allocation
2031 ** is not freed.
2032 **
2033 ** ^The memory returned by sqlite3_malloc() and sqlite3_realloc()
2034 ** is always aligned to at least an 8 byte boundary, or to a
2035 ** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
2036 ** option is used.
2037 **
2038 ** In SQLite version 3.5.0 and 3.5.1, it was possible to define
2039 ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in
2040 ** implementation of these routines to be omitted. That capability
2041 ** is no longer provided. Only built-in memory allocators can be used.
2042 **
2043 ** The Windows OS interface layer calls
2044 ** the system malloc() and free() directly when converting
2045 ** filenames between the UTF-8 encoding used by SQLite
2046 ** and whatever filename encoding is used by the particular Windows
2047 ** installation. Memory allocation errors are detected, but
2048 ** they are reported back as [SQLITE_CANTOPEN] or
2049 ** [SQLITE_IOERR] rather than [SQLITE_NOMEM].
2050 **
2051 ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
2052 ** must be either NULL or else pointers obtained from a prior
2053 ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
2054 ** not yet been released.
2055 **
2056 ** The application must not read or write any part of
2057 ** a block of memory after it has been released using
2058 ** [sqlite3_free()] or [sqlite3_realloc()].
2059 */
2064 /*
2065 ** CAPI3REF: Memory Allocator Statistics
2066 **
2067 ** SQLite provides these two interfaces for reporting on the status
2068 ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
2069 ** routines, which form the built-in memory allocation subsystem.
2070 **
2071 ** ^The [sqlite3_memory_used()] routine returns the number of bytes
2072 ** of memory currently outstanding (malloced but not freed).
2073 ** ^The [sqlite3_memory_highwater()] routine returns the maximum
2074 ** value of [sqlite3_memory_used()] since the high-water mark
2075 ** was last reset. ^The values returned by [sqlite3_memory_used()] and
2076 ** [sqlite3_memory_highwater()] include any overhead
2077 ** added by SQLite in its implementation of [sqlite3_malloc()],
2078 ** but not overhead added by the any underlying system library
2079 ** routines that [sqlite3_malloc()] may call.
2080 **
2081 ** ^The memory high-water mark is reset to the current value of
2082 ** [sqlite3_memory_used()] if and only if the parameter to
2083 ** [sqlite3_memory_highwater()] is true. ^The value returned
2084 ** by [sqlite3_memory_highwater(1)] is the high-water mark
2085 ** prior to the reset.
2086 */
2090 /*
2091 ** CAPI3REF: Pseudo-Random Number Generator
2092 **
2093 ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
2094 ** select random [ROWID | ROWIDs] when inserting new records into a table that
2095 ** already uses the largest possible [ROWID]. The PRNG is also used for
2096 ** the build-in random() and randomblob() SQL functions. This interface allows
2097 ** applications to access the same PRNG for other purposes.
2098 **
2099 ** ^A call to this routine stores N bytes of randomness into buffer P.
2100 **
2101 ** ^The first time this routine is invoked (either internally or by
2102 ** the application) the PRNG is seeded using randomness obtained
2103 ** from the xRandomness method of the default [sqlite3_vfs] object.
2104 ** ^On all subsequent invocations, the pseudo-randomness is generated
2105 ** internally and without recourse to the [sqlite3_vfs] xRandomness
2106 ** method.
2107 */
2110 /*
2111 ** CAPI3REF: Compile-Time Authorization Callbacks
2112 **
2113 ** ^This routine registers an authorizer callback with a particular
2114 ** [database connection], supplied in the first argument.
2115 ** ^The authorizer callback is invoked as SQL statements are being compiled
2116 ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
2117 ** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various
2118 ** points during the compilation process, as logic is being created
2119 ** to perform various actions, the authorizer callback is invoked to
2120 ** see if those actions are allowed. ^The authorizer callback should
2121 ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
2122 ** specific action but allow the SQL statement to continue to be
2123 ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
2124 ** rejected with an error. ^If the authorizer callback returns
2125 ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
2126 ** then the [sqlite3_prepare_v2()] or equivalent call that triggered
2127 ** the authorizer will fail with an error message.
2128 **
2129 ** When the callback returns [SQLITE_OK], that means the operation
2130 ** requested is ok. ^When the callback returns [SQLITE_DENY], the
2131 ** [sqlite3_prepare_v2()] or equivalent call that triggered the
2132 ** authorizer will fail with an error message explaining that
2133 ** access is denied.
2134 **
2135 ** ^The first parameter to the authorizer callback is a copy of the third
2136 ** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
2137 ** to the callback is an integer [SQLITE_COPY | action code] that specifies
2138 ** the particular action to be authorized. ^The third through sixth parameters
2139 ** to the callback are zero-terminated strings that contain additional
2140 ** details about the action to be authorized.
2141 **
2142 ** ^If the action code is [SQLITE_READ]
2143 ** and the callback returns [SQLITE_IGNORE] then the
2144 ** [prepared statement] statement is constructed to substitute
2145 ** a NULL value in place of the table column that would have
2146 ** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE]
2147 ** return can be used to deny an untrusted user access to individual
2148 ** columns of a table.
2149 ** ^If the action code is [SQLITE_DELETE] and the callback returns
2150 ** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
2151 ** [truncate optimization] is disabled and all rows are deleted individually.
2152 **
2153 ** An authorizer is used when [sqlite3_prepare | preparing]
2154 ** SQL statements from an untrusted source, to ensure that the SQL statements
2155 ** do not try to access data they are not allowed to see, or that they do not
2156 ** try to execute malicious statements that damage the database. For
2157 ** example, an application may allow a user to enter arbitrary
2158 ** SQL queries for evaluation by a database. But the application does
2159 ** not want the user to be able to make arbitrary changes to the
2160 ** database. An authorizer could then be put in place while the
2161 ** user-entered SQL is being [sqlite3_prepare | prepared] that
2162 ** disallows everything except [SELECT] statements.
2163 **
2164 ** Applications that need to process SQL from untrusted sources
2165 ** might also consider lowering resource limits using [sqlite3_limit()]
2166 ** and limiting database size using the [max_page_count] [PRAGMA]
2167 ** in addition to using an authorizer.
2168 **
2169 ** ^(Only a single authorizer can be in place on a database connection
2170 ** at a time. Each call to sqlite3_set_authorizer overrides the
2171 ** previous call.)^ ^Disable the authorizer by installing a NULL callback.
2172 ** The authorizer is disabled by default.
2173 **
2174 ** The authorizer callback must not do anything that will modify
2175 ** the database connection that invoked the authorizer callback.
2176 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2177 ** database connections for the meaning of "modify" in this paragraph.
2178 **
2179 ** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
2180 ** statement might be re-prepared during [sqlite3_step()] due to a
2181 ** schema change. Hence, the application should ensure that the
2182 ** correct authorizer callback remains in place during the [sqlite3_step()].
2183 **
2184 ** ^Note that the authorizer callback is invoked only during
2185 ** [sqlite3_prepare()] or its variants. Authorization is not
2186 ** performed during statement evaluation in [sqlite3_step()], unless
2187 ** as stated in the previous paragraph, sqlite3_step() invokes
2188 ** sqlite3_prepare_v2() to reprepare a statement after a schema change.
2189 */
2191 sqlite3*,
2194 );
2196 /*
2197 ** CAPI3REF: Authorizer Return Codes
2198 **
2199 ** The [sqlite3_set_authorizer | authorizer callback function] must
2200 ** return either [SQLITE_OK] or one of these two constants in order
2201 ** to signal SQLite whether or not the action is permitted. See the
2202 ** [sqlite3_set_authorizer | authorizer documentation] for additional
2203 ** information.
2204 */
2208 /*
2209 ** CAPI3REF: Authorizer Action Codes
2210 **
2211 ** The [sqlite3_set_authorizer()] interface registers a callback function
2212 ** that is invoked to authorize certain SQL statement actions. The
2213 ** second parameter to the callback is an integer code that specifies
2214 ** what action is being authorized. These are the integer action codes that
2215 ** the authorizer callback may be passed.
2216 **
2217 ** These action code values signify what kind of operation is to be
2218 ** authorized. The 3rd and 4th parameters to the authorization
2219 ** callback function will be parameters or NULL depending on which of these
2220 ** codes is used as the second parameter. ^(The 5th parameter to the
2221 ** authorizer callback is the name of the database ("main", "temp",
2222 ** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback
2223 ** is the name of the inner-most trigger or view that is responsible for
2224 ** the access attempt or NULL if this access attempt is directly from
2225 ** top-level SQL code.
2226 */
2227 /******************************************* 3rd ************ 4th ***********/
2262 /*
2263 ** CAPI3REF: Tracing And Profiling Functions
2264 **
2265 ** These routines register callback functions that can be used for
2266 ** tracing and profiling the execution of SQL statements.
2267 **
2268 ** ^The callback function registered by sqlite3_trace() is invoked at
2269 ** various times when an SQL statement is being run by [sqlite3_step()].
2270 ** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
2271 ** SQL statement text as the statement first begins executing.
2272 ** ^(Additional sqlite3_trace() callbacks might occur
2273 ** as each triggered subprogram is entered. The callbacks for triggers
2274 ** contain a UTF-8 SQL comment that identifies the trigger.)^
2275 **
2276 ** ^The callback function registered by sqlite3_profile() is invoked
2277 ** as each SQL statement finishes. ^The profile callback contains
2278 ** the original statement text and an estimate of wall-clock time
2279 ** of how long that statement took to run. ^The profile callback
2280 ** time is in units of nanoseconds, however the current implementation
2281 ** is only capable of millisecond resolution so the six least significant
2282 ** digits in the time are meaningless. Future versions of SQLite
2283 ** might provide greater resolution on the profiler callback. The
2284 ** sqlite3_profile() function is considered experimental and is
2285 ** subject to change in future versions of SQLite.
2286 */
2291 /*
2292 ** CAPI3REF: Query Progress Callbacks
2293 **
2294 ** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
2295 ** function X to be invoked periodically during long running calls to
2296 ** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for
2297 ** database connection D. An example use for this
2298 ** interface is to keep a GUI updated during a large query.
2299 **
2300 ** ^The parameter P is passed through as the only parameter to the
2301 ** callback function X. ^The parameter N is the number of
2302 ** [virtual machine instructions] that are evaluated between successive
2303 ** invocations of the callback X.
2304 **
2305 ** ^Only a single progress handler may be defined at one time per
2306 ** [database connection]; setting a new progress handler cancels the
2307 ** old one. ^Setting parameter X to NULL disables the progress handler.
2308 ** ^The progress handler is also disabled by setting N to a value less
2309 ** than 1.
2310 **
2311 ** ^If the progress callback returns non-zero, the operation is
2312 ** interrupted. This feature can be used to implement a
2313 ** "Cancel" button on a GUI progress dialog box.
2314 **
2315 ** The progress handler callback must not do anything that will modify
2316 ** the database connection that invoked the progress handler.
2317 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2318 ** database connections for the meaning of "modify" in this paragraph.
2319 **
2320 */
2323 /*
2324 ** CAPI3REF: Opening A New Database Connection
2325 **
2326 ** ^These routines open an SQLite database file whose name is given by the
2327 ** filename argument. ^The filename argument is interpreted as UTF-8 for
2328 ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
2329 ** order for sqlite3_open16(). ^(A [database connection] handle is usually
2330 ** returned in *ppDb, even if an error occurs. The only exception is that
2331 ** if SQLite is unable to allocate memory to hold the [sqlite3] object,
2332 ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
2333 ** object.)^ ^(If the database is opened (and/or created) successfully, then
2334 ** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The
2335 ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
2336 ** an English language description of the error following a failure of any
2337 ** of the sqlite3_open() routines.
2338 **
2339 ** ^The default encoding for the database will be UTF-8 if
2340 ** sqlite3_open() or sqlite3_open_v2() is called and
2341 ** UTF-16 in the native byte order if sqlite3_open16() is used.
2342 **
2343 ** Whether or not an error occurs when it is opened, resources
2344 ** associated with the [database connection] handle should be released by
2345 ** passing it to [sqlite3_close()] when it is no longer required.
2346 **
2347 ** The sqlite3_open_v2() interface works like sqlite3_open()
2348 ** except that it accepts two additional parameters for additional control
2349 ** over the new database connection. ^(The flags parameter to
2350 ** sqlite3_open_v2() can take one of
2351 ** the following three values, optionally combined with the
2352 ** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE],
2353 ** and/or [SQLITE_OPEN_PRIVATECACHE] flags:)^
2354 **
2355 ** <dl>
2356 ** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
2357 ** <dd>The database is opened in read-only mode. If the database does not
2358 ** already exist, an error is returned.</dd>)^
2359 **
2360 ** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
2361 ** <dd>The database is opened for reading and writing if possible, or reading
2362 ** only if the file is write protected by the operating system. In either
2363 ** case the database must already exist, otherwise an error is returned.</dd>)^
2364 **
2365 ** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
2366 ** <dd>The database is opened for reading and writing, and is created if
2367 ** it does not already exist. This is the behavior that is always used for
2368 ** sqlite3_open() and sqlite3_open16().</dd>)^
2369 ** </dl>
2370 **
2371 ** If the 3rd parameter to sqlite3_open_v2() is not one of the
2372 ** combinations shown above or one of the combinations shown above combined
2373 ** with the [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX],
2374 ** [SQLITE_OPEN_SHAREDCACHE] and/or [SQLITE_OPEN_PRIVATECACHE] flags,
2375 ** then the behavior is undefined.
2376 **
2377 ** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection
2378 ** opens in the multi-thread [threading mode] as long as the single-thread
2379 ** mode has not been set at compile-time or start-time. ^If the
2380 ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens
2381 ** in the serialized [threading mode] unless single-thread was
2382 ** previously selected at compile-time or start-time.
2383 ** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be
2384 ** eligible to use [shared cache mode], regardless of whether or not shared
2385 ** cache is enabled using [sqlite3_enable_shared_cache()]. ^The
2386 ** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not
2387 ** participate in [shared cache mode] even if it is enabled.
2388 **
2389 ** ^If the filename is ":memory:", then a private, temporary in-memory database
2390 ** is created for the connection. ^This in-memory database will vanish when
2391 ** the database connection is closed. Future versions of SQLite might
2392 ** make use of additional special filenames that begin with the ":" character.
2393 ** It is recommended that when a database filename actually does begin with
2394 ** a ":" character you should prefix the filename with a pathname such as
2395 ** "./" to avoid ambiguity.
2396 **
2397 ** ^If the filename is an empty string, then a private, temporary
2398 ** on-disk database will be created. ^This private database will be
2399 ** automatically deleted as soon as the database connection is closed.
2400 **
2401 ** ^The fourth parameter to sqlite3_open_v2() is the name of the
2402 ** [sqlite3_vfs] object that defines the operating system interface that
2403 ** the new database connection should use. ^If the fourth parameter is
2404 ** a NULL pointer then the default [sqlite3_vfs] object is used.
2405 **
2406 ** <b>Note to Windows users:</b> The encoding used for the filename argument
2407 ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
2408 ** codepage is currently defined. Filenames containing international
2409 ** characters must be converted to UTF-8 prior to passing them into
2410 ** sqlite3_open() or sqlite3_open_v2().
2411 */
2415 );
2419 );
2425 );
2427 /*
2428 ** CAPI3REF: Error Codes And Messages
2429 **
2430 ** ^The sqlite3_errcode() interface returns the numeric [result code] or
2431 ** [extended result code] for the most recent failed sqlite3_* API call
2432 ** associated with a [database connection]. If a prior API call failed
2433 ** but the most recent API call succeeded, the return value from
2434 ** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode()
2435 ** interface is the same except that it always returns the
2436 ** [extended result code] even when extended result codes are
2437 ** disabled.
2438 **
2439 ** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
2440 ** text that describes the error, as either UTF-8 or UTF-16 respectively.
2441 ** ^(Memory to hold the error message string is managed internally.
2442 ** The application does not need to worry about freeing the result.
2443 ** However, the error string might be overwritten or deallocated by
2444 ** subsequent calls to other SQLite interface functions.)^
2445 **
2446 ** When the serialized [threading mode] is in use, it might be the
2447 ** case that a second error occurs on a separate thread in between
2448 ** the time of the first error and the call to these interfaces.
2449 ** When that happens, the second error will be reported since these
2450 ** interfaces always report the most recent result. To avoid
2451 ** this, each thread can obtain exclusive use of the [database connection] D
2452 ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
2453 ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
2454 ** all calls to the interfaces listed here are completed.
2455 **
2456 ** If an interface fails with SQLITE_MISUSE, that means the interface
2457 ** was invoked incorrectly by the application. In that case, the
2458 ** error code and message may or may not be set.
2459 */
2465 /*
2466 ** CAPI3REF: SQL Statement Object
2467 ** KEYWORDS: {prepared statement} {prepared statements}
2468 **
2469 ** An instance of this object represents a single SQL statement.
2470 ** This object is variously known as a "prepared statement" or a
2471 ** "compiled SQL statement" or simply as a "statement".
2472 **
2473 ** The life of a statement object goes something like this:
2474 **
2475 ** <ol>
2476 ** <li> Create the object using [sqlite3_prepare_v2()] or a related
2477 ** function.
2478 ** <li> Bind values to [host parameters] using the sqlite3_bind_*()
2479 ** interfaces.
2480 ** <li> Run the SQL by calling [sqlite3_step()] one or more times.
2481 ** <li> Reset the statement using [sqlite3_reset()] then go back
2482 ** to step 2. Do this zero or more times.
2483 ** <li> Destroy the object using [sqlite3_finalize()].
2484 ** </ol>
2485 **
2486 ** Refer to documentation on individual methods above for additional
2487 ** information.
2488 */
2491 /*
2492 ** CAPI3REF: Run-time Limits
2493 **
2494 ** ^(This interface allows the size of various constructs to be limited
2495 ** on a connection by connection basis. The first parameter is the
2496 ** [database connection] whose limit is to be set or queried. The
2497 ** second parameter is one of the [limit categories] that define a
2498 ** class of constructs to be size limited. The third parameter is the
2499 ** new limit for that construct.)^
2500 **
2501 ** ^If the new limit is a negative number, the limit is unchanged.
2502 ** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
2503 ** [limits | hard upper bound]
2504 ** set at compile-time by a C preprocessor macro called
2505 ** [limits | SQLITE_MAX_<i>NAME</i>].
2506 ** (The "_LIMIT_" in the name is changed to "_MAX_".))^
2507 ** ^Attempts to increase a limit above its hard upper bound are
2508 ** silently truncated to the hard upper bound.
2509 **
2510 ** ^Regardless of whether or not the limit was changed, the
2511 ** [sqlite3_limit()] interface returns the prior value of the limit.
2512 ** ^Hence, to find the current value of a limit without changing it,
2513 ** simply invoke this interface with the third parameter set to -1.
2514 **
2515 ** Run-time limits are intended for use in applications that manage
2516 ** both their own internal database and also databases that are controlled
2517 ** by untrusted external sources. An example application might be a
2518 ** web browser that has its own databases for storing history and
2519 ** separate databases controlled by JavaScript applications downloaded
2520 ** off the Internet. The internal databases can be given the
2521 ** large, default limits. Databases managed by external sources can
2522 ** be given much smaller limits designed to prevent a denial of service
2523 ** attack. Developers might also want to use the [sqlite3_set_authorizer()]
2524 ** interface to further control untrusted SQL. The size of the database
2525 ** created by an untrusted script can be contained using the
2526 ** [max_page_count] [PRAGMA].
2527 **
2528 ** New run-time limit categories may be added in future releases.
2529 */
2532 /*
2533 ** CAPI3REF: Run-Time Limit Categories
2534 ** KEYWORDS: {limit category} {*limit categories}
2535 **
2536 ** These constants define various performance limits
2537 ** that can be lowered at run-time using [sqlite3_limit()].
2538 ** The synopsis of the meanings of the various limits is shown below.
2539 ** Additional information is available at [limits | Limits in SQLite].
2540 **
2541 ** <dl>
2542 ** ^(<dt>SQLITE_LIMIT_LENGTH</dt>
2543 ** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
2544 **
2545 ** ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
2546 ** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
2547 **
2548 ** ^(<dt>SQLITE_LIMIT_COLUMN</dt>
2549 ** <dd>The maximum number of columns in a table definition or in the
2550 ** result set of a [SELECT] or the maximum number of columns in an index
2551 ** or in an ORDER BY or GROUP BY clause.</dd>)^
2552 **
2553 ** ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
2554 ** <dd>The maximum depth of the parse tree on any expression.</dd>)^
2555 **
2556 ** ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
2557 ** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
2558 **
2559 ** ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
2560 ** <dd>The maximum number of instructions in a virtual machine program
2561 ** used to implement an SQL statement. This limit is not currently
2562 ** enforced, though that might be added in some future release of
2563 ** SQLite.</dd>)^
2564 **
2565 ** ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
2566 ** <dd>The maximum number of arguments on a function.</dd>)^
2567 **
2568 ** ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
2569 ** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
2570 **
2571 ** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
2572 ** <dd>The maximum length of the pattern argument to the [LIKE] or
2573 ** [GLOB] operators.</dd>)^
2574 **
2575 ** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
2576 ** <dd>The maximum index number of any [parameter] in an SQL statement.)^
2577 **
2578 ** ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
2579 ** <dd>The maximum depth of recursion for triggers.</dd>)^
2580 ** </dl>
2581 */
2582 #define SQLITE_LIMIT_LENGTH 0
2583 #define SQLITE_LIMIT_SQL_LENGTH 1
2584 #define SQLITE_LIMIT_COLUMN 2
2585 #define SQLITE_LIMIT_EXPR_DEPTH 3
2586 #define SQLITE_LIMIT_COMPOUND_SELECT 4
2587 #define SQLITE_LIMIT_VDBE_OP 5
2588 #define SQLITE_LIMIT_FUNCTION_ARG 6
2589 #define SQLITE_LIMIT_ATTACHED 7
2590 #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8
2591 #define SQLITE_LIMIT_VARIABLE_NUMBER 9
2592 #define SQLITE_LIMIT_TRIGGER_DEPTH 10
2594 /*
2595 ** CAPI3REF: Compiling An SQL Statement
2596 ** KEYWORDS: {SQL statement compiler}
2597 **
2598 ** To execute an SQL query, it must first be compiled into a byte-code
2599 ** program using one of these routines.
2600 **
2601 ** The first argument, "db", is a [database connection] obtained from a
2602 ** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
2603 ** [sqlite3_open16()]. The database connection must not have been closed.
2604 **
2605 ** The second argument, "zSql", is the statement to be compiled, encoded
2606 ** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2()
2607 ** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2()
2608 ** use UTF-16.
2609 **
2610 ** ^If the nByte argument is less than zero, then zSql is read up to the
2611 ** first zero terminator. ^If nByte is non-negative, then it is the maximum
2612 ** number of bytes read from zSql. ^When nByte is non-negative, the
2613 ** zSql string ends at either the first '\000' or '\u0000' character or
2614 ** the nByte-th byte, whichever comes first. If the caller knows
2615 ** that the supplied string is nul-terminated, then there is a small
2616 ** performance advantage to be gained by passing an nByte parameter that
2617 ** is equal to the number of bytes in the input string <i>including</i>
2618 ** the nul-terminator bytes.
2619 **
2620 ** ^If pzTail is not NULL then *pzTail is made to point to the first byte
2621 ** past the end of the first SQL statement in zSql. These routines only
2622 ** compile the first statement in zSql, so *pzTail is left pointing to
2623 ** what remains uncompiled.
2624 **
2625 ** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
2626 ** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set
2627 ** to NULL. ^If the input text contains no SQL (if the input is an empty
2628 ** string or a comment) then *ppStmt is set to NULL.
2629 ** The calling procedure is responsible for deleting the compiled
2630 ** SQL statement using [sqlite3_finalize()] after it has finished with it.
2631 ** ppStmt may not be NULL.
2632 **
2633 ** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
2634 ** otherwise an [error code] is returned.
2635 **
2636 ** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are
2637 ** recommended for all new programs. The two older interfaces are retained
2638 ** for backwards compatibility, but their use is discouraged.
2639 ** ^In the "v2" interfaces, the prepared statement
2640 ** that is returned (the [sqlite3_stmt] object) contains a copy of the
2641 ** original SQL text. This causes the [sqlite3_step()] interface to
2642 ** behave differently in three ways:
2643 **
2644 ** <ol>
2645 ** <li>
2646 ** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
2647 ** always used to do, [sqlite3_step()] will automatically recompile the SQL
2648 ** statement and try to run it again.
2649 ** </li>
2650 **
2651 ** <li>
2652 ** ^When an error occurs, [sqlite3_step()] will return one of the detailed
2653 ** [error codes] or [extended error codes]. ^The legacy behavior was that
2654 ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
2655 ** and the application would have to make a second call to [sqlite3_reset()]
2656 ** in order to find the underlying cause of the problem. With the "v2" prepare
2657 ** interfaces, the underlying reason for the error is returned immediately.
2658 ** </li>
2659 **
2660 ** <li>
2661 ** ^If the specific value bound to [parameter | host parameter] in the
2662 ** WHERE clause might influence the choice of query plan for a statement,
2663 ** then the statement will be automatically recompiled, as if there had been
2664 ** a schema change, on the first [sqlite3_step()] call following any change
2665 ** to the [sqlite3_bind_text | bindings] of that [parameter].
2666 ** ^The specific value of WHERE-clause [parameter] might influence the
2667 ** choice of query plan if the parameter is the left-hand side of a [LIKE]
2668 ** or [GLOB] operator or if the parameter is compared to an indexed column
2669 ** and the [SQLITE_ENABLE_STAT2] compile-time option is enabled.
2670 ** the
2671 ** </li>
2672 ** </ol>
2673 */
2680 );
2687 );
2694 );
2701 );
2703 /*
2704 ** CAPI3REF: Retrieving Statement SQL
2705 **
2706 ** ^This interface can be used to retrieve a saved copy of the original
2707 ** SQL text used to create a [prepared statement] if that statement was
2708 ** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()].
2709 */
2712 /*
2713 ** CAPI3REF: Determine If An SQL Statement Writes The Database
2714 **
2715 ** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
2716 ** and only if the [prepared statement] X makes no direct changes to
2717 ** the content of the database file.
2718 **
2719 ** Note that [application-defined SQL functions] or
2720 ** [virtual tables] might change the database indirectly as a side effect.
2721 ** ^(For example, if an application defines a function "eval()" that
2722 ** calls [sqlite3_exec()], then the following SQL statement would
2723 ** change the database file through side-effects:
2724 **
2725 ** <blockquote><pre>
2726 ** SELECT eval('DELETE FROM t1') FROM t2;
2727 ** </pre></blockquote>
2728 **
2729 ** But because the [SELECT] statement does not change the database file
2730 ** directly, sqlite3_stmt_readonly() would still return true.)^
2731 **
2732 ** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
2733 ** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
2734 ** since the statements themselves do not actually modify the database but
2735 ** rather they control the timing of when other statements modify the
2736 ** database. ^The [ATTACH] and [DETACH] statements also cause
2737 ** sqlite3_stmt_readonly() to return true since, while those statements
2738 ** change the configuration of a database connection, they do not make
2739 ** changes to the content of the database files on disk.
2740 */
2743 /*
2744 ** CAPI3REF: Dynamically Typed Value Object
2745 ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
2746 **
2747 ** SQLite uses the sqlite3_value object to represent all values
2748 ** that can be stored in a database table. SQLite uses dynamic typing
2749 ** for the values it stores. ^Values stored in sqlite3_value objects
2750 ** can be integers, floating point values, strings, BLOBs, or NULL.
2751 **
2752 ** An sqlite3_value object may be either "protected" or "unprotected".
2753 ** Some interfaces require a protected sqlite3_value. Other interfaces
2754 ** will accept either a protected or an unprotected sqlite3_value.
2755 ** Every interface that accepts sqlite3_value arguments specifies
2756 ** whether or not it requires a protected sqlite3_value.
2757 **
2758 ** The terms "protected" and "unprotected" refer to whether or not
2759 ** a mutex is held. An internal mutex is held for a protected
2760 ** sqlite3_value object but no mutex is held for an unprotected
2761 ** sqlite3_value object. If SQLite is compiled to be single-threaded
2762 ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
2763 ** or if SQLite is run in one of reduced mutex modes
2764 ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
2765 ** then there is no distinction between protected and unprotected
2766 ** sqlite3_value objects and they can be used interchangeably. However,
2767 ** for maximum code portability it is recommended that applications
2768 ** still make the distinction between protected and unprotected
2769 ** sqlite3_value objects even when not strictly required.
2770 **
2771 ** ^The sqlite3_value objects that are passed as parameters into the
2772 ** implementation of [application-defined SQL functions] are protected.
2773 ** ^The sqlite3_value object returned by
2774 ** [sqlite3_column_value()] is unprotected.
2775 ** Unprotected sqlite3_value objects may only be used with
2776 ** [sqlite3_result_value()] and [sqlite3_bind_value()].
2777 ** The [sqlite3_value_blob | sqlite3_value_type()] family of
2778 ** interfaces require protected sqlite3_value objects.
2779 */
2782 /*
2783 ** CAPI3REF: SQL Function Context Object
2784 **
2785 ** The context in which an SQL function executes is stored in an
2786 ** sqlite3_context object. ^A pointer to an sqlite3_context object
2787 ** is always first parameter to [application-defined SQL functions].
2788 ** The application-defined SQL function implementation will pass this
2789 ** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
2790 ** [sqlite3_aggregate_context()], [sqlite3_user_data()],
2791 ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
2792 ** and/or [sqlite3_set_auxdata()].
2793 */
2796 /*
2797 ** CAPI3REF: Binding Values To Prepared Statements
2798 ** KEYWORDS: {host parameter} {host parameters} {host parameter name}
2799 ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
2800 **
2801 ** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
2802 ** literals may be replaced by a [parameter] that matches one of following
2803 ** templates:
2804 **
2805 ** <ul>
2806 ** <li> ?
2807 ** <li> ?NNN
2808 ** <li> :VVV
2809 ** <li> @VVV
2810 ** <li> $VVV
2811 ** </ul>
2812 **
2813 ** In the templates above, NNN represents an integer literal,
2814 ** and VVV represents an alphanumeric identifier.)^ ^The values of these
2815 ** parameters (also called "host parameter names" or "SQL parameters")
2816 ** can be set using the sqlite3_bind_*() routines defined here.
2817 **
2818 ** ^The first argument to the sqlite3_bind_*() routines is always
2819 ** a pointer to the [sqlite3_stmt] object returned from
2820 ** [sqlite3_prepare_v2()] or its variants.
2821 **
2822 ** ^The second argument is the index of the SQL parameter to be set.
2823 ** ^The leftmost SQL parameter has an index of 1. ^When the same named
2824 ** SQL parameter is used more than once, second and subsequent
2825 ** occurrences have the same index as the first occurrence.
2826 ** ^The index for named parameters can be looked up using the
2827 ** [sqlite3_bind_parameter_index()] API if desired. ^The index
2828 ** for "?NNN" parameters is the value of NNN.
2829 ** ^The NNN value must be between 1 and the [sqlite3_limit()]
2830 ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999).
2831 **
2832 ** ^The third argument is the value to bind to the parameter.
2833 **
2834 ** ^(In those routines that have a fourth argument, its value is the
2835 ** number of bytes in the parameter. To be clear: the value is the
2836 ** number of <u>bytes</u> in the value, not the number of characters.)^
2837 ** ^If the fourth parameter is negative, the length of the string is
2838 ** the number of bytes up to the first zero terminator.
2839 **
2840 ** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and
2841 ** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or
2842 ** string after SQLite has finished with it. ^The destructor is called
2843 ** to dispose of the BLOB or string even if the call to sqlite3_bind_blob(),
2844 ** sqlite3_bind_text(), or sqlite3_bind_text16() fails.
2845 ** ^If the fifth argument is
2846 ** the special value [SQLITE_STATIC], then SQLite assumes that the
2847 ** information is in static, unmanaged space and does not need to be freed.
2848 ** ^If the fifth argument has the value [SQLITE_TRANSIENT], then
2849 ** SQLite makes its own private copy of the data immediately, before
2850 ** the sqlite3_bind_*() routine returns.
2851 **
2852 ** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
2853 ** is filled with zeroes. ^A zeroblob uses a fixed amount of memory
2854 ** (just an integer to hold its size) while it is being processed.
2855 ** Zeroblobs are intended to serve as placeholders for BLOBs whose
2856 ** content is later written using
2857 ** [sqlite3_blob_open | incremental BLOB I/O] routines.
2858 ** ^A negative value for the zeroblob results in a zero-length BLOB.
2859 **
2860 ** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
2861 ** for the [prepared statement] or with a prepared statement for which
2862 ** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
2863 ** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_()
2864 ** routine is passed a [prepared statement] that has been finalized, the
2865 ** result is undefined and probably harmful.
2866 **
2867 ** ^Bindings are not cleared by the [sqlite3_reset()] routine.
2868 ** ^Unbound parameters are interpreted as NULL.
2869 **
2870 ** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
2871 ** [error code] if anything goes wrong.
2872 ** ^[SQLITE_RANGE] is returned if the parameter
2873 ** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails.
2874 **
2875 ** See also: [sqlite3_bind_parameter_count()],
2876 ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
2877 */
2888 /*
2889 ** CAPI3REF: Number Of SQL Parameters
2890 **
2891 ** ^This routine can be used to find the number of [SQL parameters]
2892 ** in a [prepared statement]. SQL parameters are tokens of the
2893 ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
2894 ** placeholders for values that are [sqlite3_bind_blob | bound]
2895 ** to the parameters at a later time.
2896 **
2897 ** ^(This routine actually returns the index of the largest (rightmost)
2898 ** parameter. For all forms except ?NNN, this will correspond to the
2899 ** number of unique parameters. If parameters of the ?NNN form are used,
2900 ** there may be gaps in the list.)^
2901 **
2902 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
2903 ** [sqlite3_bind_parameter_name()], and
2904 ** [sqlite3_bind_parameter_index()].
2905 */
2908 /*
2909 ** CAPI3REF: Name Of A Host Parameter
2910 **
2911 ** ^The sqlite3_bind_parameter_name(P,N) interface returns
2912 ** the name of the N-th [SQL parameter] in the [prepared statement] P.
2913 ** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
2914 ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
2915 ** respectively.
2916 ** In other words, the initial ":" or "$" or "@" or "?"
2917 ** is included as part of the name.)^
2918 ** ^Parameters of the form "?" without a following integer have no name
2919 ** and are referred to as "nameless" or "anonymous parameters".
2920 **
2921 ** ^The first host parameter has an index of 1, not 0.
2922 **
2923 ** ^If the value N is out of range or if the N-th parameter is
2924 ** nameless, then NULL is returned. ^The returned string is
2925 ** always in UTF-8 encoding even if the named parameter was
2926 ** originally specified as UTF-16 in [sqlite3_prepare16()] or
2927 ** [sqlite3_prepare16_v2()].
2928 **
2929 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
2930 ** [sqlite3_bind_parameter_count()], and
2931 ** [sqlite3_bind_parameter_index()].
2932 */
2935 /*
2936 ** CAPI3REF: Index Of A Parameter With A Given Name
2937 **
2938 ** ^Return the index of an SQL parameter given its name. ^The
2939 ** index value returned is suitable for use as the second
2940 ** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero
2941 ** is returned if no matching parameter is found. ^The parameter
2942 ** name must be given in UTF-8 even if the original statement
2943 ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()].
2944 **
2945 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
2946 ** [sqlite3_bind_parameter_count()], and
2947 ** [sqlite3_bind_parameter_index()].
2948 */
2951 /*
2952 ** CAPI3REF: Reset All Bindings On A Prepared Statement
2953 **
2954 ** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
2955 ** the [sqlite3_bind_blob | bindings] on a [prepared statement].
2956 ** ^Use this routine to reset all host parameters to NULL.
2957 */
2960 /*
2961 ** CAPI3REF: Number Of Columns In A Result Set
2962 **
2963 ** ^Return the number of columns in the result set returned by the
2964 ** [prepared statement]. ^This routine returns 0 if pStmt is an SQL
2965 ** statement that does not return data (for example an [UPDATE]).
2966 **
2967 ** See also: [sqlite3_data_count()]
2968 */
2971 /*
2972 ** CAPI3REF: Column Names In A Result Set
2973 **
2974 ** ^These routines return the name assigned to a particular column
2975 ** in the result set of a [SELECT] statement. ^The sqlite3_column_name()
2976 ** interface returns a pointer to a zero-terminated UTF-8 string
2977 ** and sqlite3_column_name16() returns a pointer to a zero-terminated
2978 ** UTF-16 string. ^The first parameter is the [prepared statement]
2979 ** that implements the [SELECT] statement. ^The second parameter is the
2980 ** column number. ^The leftmost column is number 0.
2981 **
2982 ** ^The returned string pointer is valid until either the [prepared statement]
2983 ** is destroyed by [sqlite3_finalize()] or until the statement is automatically
2984 ** reprepared by the first call to [sqlite3_step()] for a particular run
2985 ** or until the next call to
2986 ** sqlite3_column_name() or sqlite3_column_name16() on the same column.
2987 **
2988 ** ^If sqlite3_malloc() fails during the processing of either routine
2989 ** (for example during a conversion from UTF-8 to UTF-16) then a
2990 ** NULL pointer is returned.
2991 **
2992 ** ^The name of a result column is the value of the "AS" clause for
2993 ** that column, if there is an AS clause. If there is no AS clause
2994 ** then the name of the column is unspecified and may change from
2995 ** one release of SQLite to the next.
2996 */
3000 /*
3001 ** CAPI3REF: Source Of Data In A Query Result
3002 **
3003 ** ^These routines provide a means to determine the database, table, and
3004 ** table column that is the origin of a particular result column in
3005 ** [SELECT] statement.
3006 ** ^The name of the database or table or column can be returned as
3007 ** either a UTF-8 or UTF-16 string. ^The _database_ routines return
3008 ** the database name, the _table_ routines return the table name, and
3009 ** the origin_ routines return the column name.
3010 ** ^The returned string is valid until the [prepared statement] is destroyed
3011 ** using [sqlite3_finalize()] or until the statement is automatically
3012 ** reprepared by the first call to [sqlite3_step()] for a particular run
3013 ** or until the same information is requested
3014 ** again in a different encoding.
3015 **
3016 ** ^The names returned are the original un-aliased names of the
3017 ** database, table, and column.
3018 **
3019 ** ^The first argument to these interfaces is a [prepared statement].
3020 ** ^These functions return information about the Nth result column returned by
3021 ** the statement, where N is the second function argument.
3022 ** ^The left-most column is column 0 for these routines.
3023 **
3024 ** ^If the Nth column returned by the statement is an expression or
3025 ** subquery and is not a column value, then all of these functions return
3026 ** NULL. ^These routine might also return NULL if a memory allocation error
3027 ** occurs. ^Otherwise, they return the name of the attached database, table,
3028 ** or column that query result column was extracted from.
3029 **
3030 ** ^As with all other SQLite APIs, those whose names end with "16" return
3031 ** UTF-16 encoded strings and the other functions return UTF-8.
3032 **
3033 ** ^These APIs are only available if the library was compiled with the
3034 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
3035 **
3036 ** If two or more threads call one or more of these routines against the same
3037 ** prepared statement and column at the same time then the results are
3038 ** undefined.
3039 **
3040 ** If two or more threads call one or more
3041 ** [sqlite3_column_database_name | column metadata interfaces]
3042 ** for the same [prepared statement] and result column
3043 ** at the same time then the results are undefined.
3044 */
3052 /*
3053 ** CAPI3REF: Declared Datatype Of A Query Result
3054 **
3055 ** ^(The first parameter is a [prepared statement].
3056 ** If this statement is a [SELECT] statement and the Nth column of the
3057 ** returned result set of that [SELECT] is a table column (not an
3058 ** expression or subquery) then the declared type of the table
3059 ** column is returned.)^ ^If the Nth column of the result set is an
3060 ** expression or subquery, then a NULL pointer is returned.
3061 ** ^The returned string is always UTF-8 encoded.
3062 **
3063 ** ^(For example, given the database schema:
3064 **
3065 ** CREATE TABLE t1(c1 VARIANT);
3066 **
3067 ** and the following statement to be compiled:
3068 **
3069 ** SELECT c1 + 1, c1 FROM t1;
3070 **
3071 ** this routine would return the string "VARIANT" for the second result
3072 ** column (i==1), and a NULL pointer for the first result column (i==0).)^
3073 **
3074 ** ^SQLite uses dynamic run-time typing. ^So just because a column
3075 ** is declared to contain a particular type does not mean that the
3076 ** data stored in that column is of the declared type. SQLite is
3077 ** strongly typed, but the typing is dynamic not static. ^Type
3078 ** is associated with individual values, not with the containers
3079 ** used to hold those values.
3080 */
3084 /*
3085 ** CAPI3REF: Evaluate An SQL Statement
3086 **
3087 ** After a [prepared statement] has been prepared using either
3088 ** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy
3089 ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
3090 ** must be called one or more times to evaluate the statement.
3091 **
3092 ** The details of the behavior of the sqlite3_step() interface depend
3093 ** on whether the statement was prepared using the newer "v2" interface
3094 ** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy
3095 ** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the
3096 ** new "v2" interface is recommended for new applications but the legacy
3097 ** interface will continue to be supported.
3098 **
3099 ** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
3100 ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
3101 ** ^With the "v2" interface, any of the other [result codes] or
3102 ** [extended result codes] might be returned as well.
3103 **
3104 ** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
3105 ** database locks it needs to do its job. ^If the statement is a [COMMIT]
3106 ** or occurs outside of an explicit transaction, then you can retry the
3107 ** statement. If the statement is not a [COMMIT] and occurs within a
3108 ** explicit transaction then you should rollback the transaction before
3109 ** continuing.
3110 **
3111 ** ^[SQLITE_DONE] means that the statement has finished executing
3112 ** successfully. sqlite3_step() should not be called again on this virtual
3113 ** machine without first calling [sqlite3_reset()] to reset the virtual
3114 ** machine back to its initial state.
3115 **
3116 ** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
3117 ** is returned each time a new row of data is ready for processing by the
3118 ** caller. The values may be accessed using the [column access functions].
3119 ** sqlite3_step() is called again to retrieve the next row of data.
3120 **
3121 ** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
3122 ** violation) has occurred. sqlite3_step() should not be called again on
3123 ** the VM. More information may be found by calling [sqlite3_errmsg()].
3124 ** ^With the legacy interface, a more specific error code (for example,
3125 ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
3126 ** can be obtained by calling [sqlite3_reset()] on the
3127 ** [prepared statement]. ^In the "v2" interface,
3128 ** the more specific error code is returned directly by sqlite3_step().
3129 **
3130 ** [SQLITE_MISUSE] means that the this routine was called inappropriately.
3131 ** Perhaps it was called on a [prepared statement] that has
3132 ** already been [sqlite3_finalize | finalized] or on one that had
3133 ** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could
3134 ** be the case that the same database connection is being used by two or
3135 ** more threads at the same moment in time.
3136 **
3137 ** For all versions of SQLite up to and including 3.6.23.1, a call to
3138 ** [sqlite3_reset()] was required after sqlite3_step() returned anything
3139 ** other than [SQLITE_ROW] before any subsequent invocation of
3140 ** sqlite3_step(). Failure to reset the prepared statement using
3141 ** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
3142 ** sqlite3_step(). But after version 3.6.23.1, sqlite3_step() began
3143 ** calling [sqlite3_reset()] automatically in this circumstance rather
3144 ** than returning [SQLITE_MISUSE]. This is not considered a compatibility
3145 ** break because any application that ever receives an SQLITE_MISUSE error
3146 ** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option
3147 ** can be used to restore the legacy behavior.
3148 **
3149 ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
3150 ** API always returns a generic error code, [SQLITE_ERROR], following any
3151 ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call
3152 ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
3153 ** specific [error codes] that better describes the error.
3154 ** We admit that this is a goofy design. The problem has been fixed
3155 ** with the "v2" interface. If you prepare all of your SQL statements
3156 ** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead
3157 ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
3158 ** then the more specific [error codes] are returned directly
3159 ** by sqlite3_step(). The use of the "v2" interface is recommended.
3160 */
3163 /*
3164 ** CAPI3REF: Number of columns in a result set
3165 **
3166 ** ^The sqlite3_data_count(P) interface returns the number of columns in the
3167 ** current row of the result set of [prepared statement] P.
3168 ** ^If prepared statement P does not have results ready to return
3169 ** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of
3170 ** interfaces) then sqlite3_data_count(P) returns 0.
3171 ** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
3172 **
3173 ** See also: [sqlite3_column_count()]
3174 */
3177 /*
3178 ** CAPI3REF: Fundamental Datatypes
3179 ** KEYWORDS: SQLITE_TEXT
3180 **
3181 ** ^(Every value in SQLite has one of five fundamental datatypes:
3182 **
3183 ** <ul>
3184 ** <li> 64-bit signed integer
3185 ** <li> 64-bit IEEE floating point number
3186 ** <li> string
3187 ** <li> BLOB
3188 ** <li> NULL
3189 ** </ul>)^
3190 **
3191 ** These constants are codes for each of those types.
3192 **
3193 ** Note that the SQLITE_TEXT constant was also used in SQLite version 2
3194 ** for a completely different meaning. Software that links against both
3195 ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
3196 ** SQLITE_TEXT.
3197 */
3198 #define SQLITE_INTEGER 1
3199 #define SQLITE_FLOAT 2
3200 #define SQLITE_BLOB 4
3201 #define SQLITE_NULL 5
3202 #ifdef SQLITE_TEXT
3203 # undef SQLITE_TEXT
3204 #else
3205 # define SQLITE_TEXT 3
3206 #endif
3207 #define SQLITE3_TEXT 3
3209 /*
3210 ** CAPI3REF: Result Values From A Query
3211 ** KEYWORDS: {column access functions}
3212 **
3213 ** These routines form the "result set" interface.
3214 **
3215 ** ^These routines return information about a single column of the current
3216 ** result row of a query. ^In every case the first argument is a pointer
3217 ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
3218 ** that was returned from [sqlite3_prepare_v2()] or one of its variants)
3219 ** and the second argument is the index of the column for which information
3220 ** should be returned. ^The leftmost column of the result set has the index 0.
3221 ** ^The number of columns in the result can be determined using
3222 ** [sqlite3_column_count()].
3223 **
3224 ** If the SQL statement does not currently point to a valid row, or if the
3225 ** column index is out of range, the result is undefined.
3226 ** These routines may only be called when the most recent call to
3227 ** [sqlite3_step()] has returned [SQLITE_ROW] and neither
3228 ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
3229 ** If any of these routines are called after [sqlite3_reset()] or
3230 ** [sqlite3_finalize()] or after [sqlite3_step()] has returned
3231 ** something other than [SQLITE_ROW], the results are undefined.
3232 ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
3233 ** are called from a different thread while any of these routines
3234 ** are pending, then the results are undefined.
3235 **
3236 ** ^The sqlite3_column_type() routine returns the
3237 ** [SQLITE_INTEGER | datatype code] for the initial data type
3238 ** of the result column. ^The returned value is one of [SQLITE_INTEGER],
3239 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value
3240 ** returned by sqlite3_column_type() is only meaningful if no type
3241 ** conversions have occurred as described below. After a type conversion,
3242 ** the value returned by sqlite3_column_type() is undefined. Future
3243 ** versions of SQLite may change the behavior of sqlite3_column_type()
3244 ** following a type conversion.
3245 **
3246 ** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
3247 ** routine returns the number of bytes in that BLOB or string.
3248 ** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
3249 ** the string to UTF-8 and then returns the number of bytes.
3250 ** ^If the result is a numeric value then sqlite3_column_bytes() uses
3251 ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
3252 ** the number of bytes in that string.
3253 ** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
3254 **
3255 ** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
3256 ** routine returns the number of bytes in that BLOB or string.
3257 ** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
3258 ** the string to UTF-16 and then returns the number of bytes.
3259 ** ^If the result is a numeric value then sqlite3_column_bytes16() uses
3260 ** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
3261 ** the number of bytes in that string.
3262 ** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
3263 **
3264 ** ^The values returned by [sqlite3_column_bytes()] and
3265 ** [sqlite3_column_bytes16()] do not include the zero terminators at the end
3266 ** of the string. ^For clarity: the values returned by
3267 ** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
3268 ** bytes in the string, not the number of characters.
3269 **
3270 ** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
3271 ** even empty strings, are always zero terminated. ^The return
3272 ** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
3273 **
3274 ** ^The object returned by [sqlite3_column_value()] is an
3275 ** [unprotected sqlite3_value] object. An unprotected sqlite3_value object
3276 ** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()].
3277 ** If the [unprotected sqlite3_value] object returned by
3278 ** [sqlite3_column_value()] is used in any other way, including calls
3279 ** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
3280 ** or [sqlite3_value_bytes()], then the behavior is undefined.
3281 **
3282 ** These routines attempt to convert the value where appropriate. ^For
3283 ** example, if the internal representation is FLOAT and a text result
3284 ** is requested, [sqlite3_snprintf()] is used internally to perform the
3285 ** conversion automatically. ^(The following table details the conversions
3286 ** that are applied:
3287 **
3288 ** <blockquote>
3289 ** <table border="1">
3290 ** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion
3291 **
3292 ** <tr><td> NULL <td> INTEGER <td> Result is 0
3293 ** <tr><td> NULL <td> FLOAT <td> Result is 0.0
3294 ** <tr><td> NULL <td> TEXT <td> Result is NULL pointer
3295 ** <tr><td> NULL <td> BLOB <td> Result is NULL pointer
3296 ** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float
3297 ** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer
3298 ** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT
3299 ** <tr><td> FLOAT <td> INTEGER <td> Convert from float to integer
3300 ** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float
3301 ** <tr><td> FLOAT <td> BLOB <td> Same as FLOAT->TEXT
3302 ** <tr><td> TEXT <td> INTEGER <td> Use atoi()
3303 ** <tr><td> TEXT <td> FLOAT <td> Use atof()
3304 ** <tr><td> TEXT <td> BLOB <td> No change
3305 ** <tr><td> BLOB <td> INTEGER <td> Convert to TEXT then use atoi()
3306 ** <tr><td> BLOB <td> FLOAT <td> Convert to TEXT then use atof()
3307 ** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed
3308 ** </table>
3309 ** </blockquote>)^
3310 **
3311 ** The table above makes reference to standard C library functions atoi()
3312 ** and atof(). SQLite does not really use these functions. It has its
3313 ** own equivalent internal routines. The atoi() and atof() names are
3314 ** used in the table for brevity and because they are familiar to most
3315 ** C programmers.
3316 **
3317 ** Note that when type conversions occur, pointers returned by prior
3318 ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
3319 ** sqlite3_column_text16() may be invalidated.
3320 ** Type conversions and pointer invalidations might occur
3321 ** in the following cases:
3322 **
3323 ** <ul>
3324 ** <li> The initial content is a BLOB and sqlite3_column_text() or
3325 ** sqlite3_column_text16() is called. A zero-terminator might
3326 ** need to be added to the string.</li>
3327 ** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
3328 ** sqlite3_column_text16() is called. The content must be converted
3329 ** to UTF-16.</li>
3330 ** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
3331 ** sqlite3_column_text() is called. The content must be converted
3332 ** to UTF-8.</li>
3333 ** </ul>
3334 **
3335 ** ^Conversions between UTF-16be and UTF-16le are always done in place and do
3336 ** not invalidate a prior pointer, though of course the content of the buffer
3337 ** that the prior pointer references will have been modified. Other kinds
3338 ** of conversion are done in place when it is possible, but sometimes they
3339 ** are not possible and in those cases prior pointers are invalidated.
3340 **
3341 ** The safest and easiest to remember policy is to invoke these routines
3342 ** in one of the following ways:
3343 **
3344 ** <ul>
3345 ** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
3346 ** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
3347 ** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
3348 ** </ul>
3349 **
3350 ** In other words, you should call sqlite3_column_text(),
3351 ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
3352 ** into the desired format, then invoke sqlite3_column_bytes() or
3353 ** sqlite3_column_bytes16() to find the size of the result. Do not mix calls
3354 ** to sqlite3_column_text() or sqlite3_column_blob() with calls to
3355 ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
3356 ** with calls to sqlite3_column_bytes().
3357 **
3358 ** ^The pointers returned are valid until a type conversion occurs as
3359 ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
3360 ** [sqlite3_finalize()] is called. ^The memory space used to hold strings
3361 ** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned
3362 ** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
3363 ** [sqlite3_free()].
3364 **
3365 ** ^(If a memory allocation error occurs during the evaluation of any
3366 ** of these routines, a default value is returned. The default value
3367 ** is either the integer 0, the floating point number 0.0, or a NULL
3368 ** pointer. Subsequent calls to [sqlite3_errcode()] will return
3369 ** [SQLITE_NOMEM].)^
3370 */
3382 /*
3383 ** CAPI3REF: Destroy A Prepared Statement Object
3384 **
3385 ** ^The sqlite3_finalize() function is called to delete a [prepared statement].
3386 ** ^If the most recent evaluation of the statement encountered no errors or
3387 ** or if the statement is never been evaluated, then sqlite3_finalize() returns
3388 ** SQLITE_OK. ^If the most recent evaluation of statement S failed, then
3389 ** sqlite3_finalize(S) returns the appropriate [error code] or
3390 ** [extended error code].
3391 **
3392 ** ^The sqlite3_finalize(S) routine can be called at any point during
3393 ** the life cycle of [prepared statement] S:
3394 ** before statement S is ever evaluated, after
3395 ** one or more calls to [sqlite3_reset()], or after any call
3396 ** to [sqlite3_step()] regardless of whether or not the statement has
3397 ** completed execution.
3398 **
3399 ** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
3400 **
3401 ** The application must finalize every [prepared statement] in order to avoid
3402 ** resource leaks. It is a grievous error for the application to try to use
3403 ** a prepared statement after it has been finalized. Any use of a prepared
3404 ** statement after it has been finalized can result in undefined and
3405 ** undesirable behavior such as segfaults and heap corruption.
3406 */
3409 /*
3410 ** CAPI3REF: Reset A Prepared Statement Object
3411 **
3412 ** The sqlite3_reset() function is called to reset a [prepared statement]
3413 ** object back to its initial state, ready to be re-executed.
3414 ** ^Any SQL statement variables that had values bound to them using
3415 ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
3416 ** Use [sqlite3_clear_bindings()] to reset the bindings.
3417 **
3418 ** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
3419 ** back to the beginning of its program.
3420 **
3421 ** ^If the most recent call to [sqlite3_step(S)] for the
3422 ** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
3423 ** or if [sqlite3_step(S)] has never before been called on S,
3424 ** then [sqlite3_reset(S)] returns [SQLITE_OK].
3425 **
3426 ** ^If the most recent call to [sqlite3_step(S)] for the
3427 ** [prepared statement] S indicated an error, then
3428 ** [sqlite3_reset(S)] returns an appropriate [error code].
3429 **
3430 ** ^The [sqlite3_reset(S)] interface does not change the values
3431 ** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
3432 */
3435 /*
3436 ** CAPI3REF: Create Or Redefine SQL Functions
3437 ** KEYWORDS: {function creation routines}
3438 ** KEYWORDS: {application-defined SQL function}
3439 ** KEYWORDS: {application-defined SQL functions}
3440 **
3441 ** ^These functions (collectively known as "function creation routines")
3442 ** are used to add SQL functions or aggregates or to redefine the behavior
3443 ** of existing SQL functions or aggregates. The only differences between
3444 ** these routines are the text encoding expected for
3445 ** the second parameter (the name of the function being created)
3446 ** and the presence or absence of a destructor callback for
3447 ** the application data pointer.
3448 **
3449 ** ^The first parameter is the [database connection] to which the SQL
3450 ** function is to be added. ^If an application uses more than one database
3451 ** connection then application-defined SQL functions must be added
3452 ** to each database connection separately.
3453 **
3454 ** ^The second parameter is the name of the SQL function to be created or
3455 ** redefined. ^The length of the name is limited to 255 bytes in a UTF-8
3456 ** representation, exclusive of the zero-terminator. ^Note that the name
3457 ** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
3458 ** ^Any attempt to create a function with a longer name
3459 ** will result in [SQLITE_MISUSE] being returned.
3460 **
3461 ** ^The third parameter (nArg)
3462 ** is the number of arguments that the SQL function or
3463 ** aggregate takes. ^If this parameter is -1, then the SQL function or
3464 ** aggregate may take any number of arguments between 0 and the limit
3465 ** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third
3466 ** parameter is less than -1 or greater than 127 then the behavior is
3467 ** undefined.
3468 **
3469 ** ^The fourth parameter, eTextRep, specifies what
3470 ** [SQLITE_UTF8 | text encoding] this SQL function prefers for
3471 ** its parameters. Every SQL function implementation must be able to work
3472 ** with UTF-8, UTF-16le, or UTF-16be. But some implementations may be
3473 ** more efficient with one encoding than another. ^An application may
3474 ** invoke sqlite3_create_function() or sqlite3_create_function16() multiple
3475 ** times with the same function but with different values of eTextRep.
3476 ** ^When multiple implementations of the same function are available, SQLite
3477 ** will pick the one that involves the least amount of data conversion.
3478 ** If there is only a single implementation which does not care what text
3479 ** encoding is used, then the fourth argument should be [SQLITE_ANY].
3480 **
3481 ** ^(The fifth parameter is an arbitrary pointer. The implementation of the
3482 ** function can gain access to this pointer using [sqlite3_user_data()].)^
3483 **
3484 ** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are
3485 ** pointers to C-language functions that implement the SQL function or
3486 ** aggregate. ^A scalar SQL function requires an implementation of the xFunc
3487 ** callback only; NULL pointers must be passed as the xStep and xFinal
3488 ** parameters. ^An aggregate SQL function requires an implementation of xStep
3489 ** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
3490 ** SQL function or aggregate, pass NULL pointers for all three function
3491 ** callbacks.
3492 **
3493 ** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL,
3494 ** then it is destructor for the application data pointer.
3495 ** The destructor is invoked when the function is deleted, either by being
3496 ** overloaded or when the database connection closes.)^
3497 ** ^The destructor is also invoked if the call to
3498 ** sqlite3_create_function_v2() fails.
3499 ** ^When the destructor callback of the tenth parameter is invoked, it
3500 ** is passed a single argument which is a copy of the application data
3501 ** pointer which was the fifth parameter to sqlite3_create_function_v2().
3502 **
3503 ** ^It is permitted to register multiple implementations of the same
3504 ** functions with the same name but with either differing numbers of
3505 ** arguments or differing preferred text encodings. ^SQLite will use
3506 ** the implementation that most closely matches the way in which the
3507 ** SQL function is used. ^A function implementation with a non-negative
3508 ** nArg parameter is a better match than a function implementation with
3509 ** a negative nArg. ^A function where the preferred text encoding
3510 ** matches the database encoding is a better
3511 ** match than a function where the encoding is different.
3512 ** ^A function where the encoding difference is between UTF16le and UTF16be
3513 ** is a closer match than a function where the encoding difference is
3514 ** between UTF8 and UTF16.
3515 **
3516 ** ^Built-in functions may be overloaded by new application-defined functions.
3517 **
3518 ** ^An application-defined function is permitted to call other
3519 ** SQLite interfaces. However, such calls must not
3520 ** close the database connection nor finalize or reset the prepared
3521 ** statement in which the function is running.
3522 */
3532 );
3542 );
3553 );
3555 /*
3556 ** CAPI3REF: Text Encodings
3557 **
3558 ** These constant define integer codes that represent the various
3559 ** text encodings supported by SQLite.
3560 */
3561 #define SQLITE_UTF8 1
3562 #define SQLITE_UTF16LE 2
3563 #define SQLITE_UTF16BE 3
3568 /*
3569 ** CAPI3REF: Deprecated Functions
3570 ** DEPRECATED
3571 **
3572 ** These functions are [deprecated]. In order to maintain
3573 ** backwards compatibility with older code, these functions continue
3574 ** to be supported. However, new applications should avoid
3575 ** the use of these functions. To help encourage people to avoid
3576 ** using these functions, we are not going to tell you what they do.
3577 */
3578 #ifndef SQLITE_OMIT_DEPRECATED
3584 SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64);
3585 #endif
3587 /*
3588 ** CAPI3REF: Obtaining SQL Function Parameter Values
3589 **
3590 ** The C-language implementation of SQL functions and aggregates uses
3591 ** this set of interface routines to access the parameter values on
3592 ** the function or aggregate.
3593 **
3594 ** The xFunc (for scalar functions) or xStep (for aggregates) parameters
3595 ** to [sqlite3_create_function()] and [sqlite3_create_function16()]
3596 ** define callbacks that implement the SQL functions and aggregates.
3597 ** The 3rd parameter to these callbacks is an array of pointers to
3598 ** [protected sqlite3_value] objects. There is one [sqlite3_value] object for
3599 ** each parameter to the SQL function. These routines are used to
3600 ** extract values from the [sqlite3_value] objects.
3601 **
3602 ** These routines work only with [protected sqlite3_value] objects.
3603 ** Any attempt to use these routines on an [unprotected sqlite3_value]
3604 ** object results in undefined behavior.
3605 **
3606 ** ^These routines work just like the corresponding [column access functions]
3607 ** except that these routines take a single [protected sqlite3_value] object
3608 ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
3609 **
3610 ** ^The sqlite3_value_text16() interface extracts a UTF-16 string
3611 ** in the native byte-order of the host machine. ^The
3612 ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
3613 ** extract UTF-16 strings as big-endian and little-endian respectively.
3614 **
3615 ** ^(The sqlite3_value_numeric_type() interface attempts to apply
3616 ** numeric affinity to the value. This means that an attempt is
3617 ** made to convert the value to an integer or floating point. If
3618 ** such a conversion is possible without loss of information (in other
3619 ** words, if the value is a string that looks like a number)
3620 ** then the conversion is performed. Otherwise no conversion occurs.
3621 ** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
3622 **
3623 ** Please pay particular attention to the fact that the pointer returned
3624 ** from [sqlite3_value_blob()], [sqlite3_value_text()], or
3625 ** [sqlite3_value_text16()] can be invalidated by a subsequent call to
3626 ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
3627 ** or [sqlite3_value_text16()].
3628 **
3629 ** These routines must be called from the same thread as
3630 ** the SQL function that supplied the [sqlite3_value*] parameters.
3631 */
3645 /*
3646 ** CAPI3REF: Obtain Aggregate Function Context
3647 **
3648 ** Implementations of aggregate SQL functions use this
3649 ** routine to allocate memory for storing their state.
3650 **
3651 ** ^The first time the sqlite3_aggregate_context(C,N) routine is called
3652 ** for a particular aggregate function, SQLite
3653 ** allocates N of memory, zeroes out that memory, and returns a pointer
3654 ** to the new memory. ^On second and subsequent calls to
3655 ** sqlite3_aggregate_context() for the same aggregate function instance,
3656 ** the same buffer is returned. Sqlite3_aggregate_context() is normally
3657 ** called once for each invocation of the xStep callback and then one
3658 ** last time when the xFinal callback is invoked. ^(When no rows match
3659 ** an aggregate query, the xStep() callback of the aggregate function
3660 ** implementation is never called and xFinal() is called exactly once.
3661 ** In those cases, sqlite3_aggregate_context() might be called for the
3662 ** first time from within xFinal().)^
3663 **
3664 ** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer if N is
3665 ** less than or equal to zero or if a memory allocate error occurs.
3666 **
3667 ** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
3668 ** determined by the N parameter on first successful call. Changing the
3669 ** value of N in subsequent call to sqlite3_aggregate_context() within
3670 ** the same aggregate function instance will not resize the memory
3671 ** allocation.)^
3672 **
3673 ** ^SQLite automatically frees the memory allocated by
3674 ** sqlite3_aggregate_context() when the aggregate query concludes.
3675 **
3676 ** The first parameter must be a copy of the
3677 ** [sqlite3_context | SQL function context] that is the first parameter
3678 ** to the xStep or xFinal callback routine that implements the aggregate
3679 ** function.
3680 **
3681 ** This routine must be called from the same thread in which
3682 ** the aggregate SQL function is running.
3683 */
3686 /*
3687 ** CAPI3REF: User Data For Functions
3688 **
3689 ** ^The sqlite3_user_data() interface returns a copy of
3690 ** the pointer that was the pUserData parameter (the 5th parameter)
3691 ** of the [sqlite3_create_function()]
3692 ** and [sqlite3_create_function16()] routines that originally
3693 ** registered the application defined function.
3694 **
3695 ** This routine must be called from the same thread in which
3696 ** the application-defined function is running.
3697 */
3700 /*
3701 ** CAPI3REF: Database Connection For Functions
3702 **
3703 ** ^The sqlite3_context_db_handle() interface returns a copy of
3704 ** the pointer to the [database connection] (the 1st parameter)
3705 ** of the [sqlite3_create_function()]
3706 ** and [sqlite3_create_function16()] routines that originally
3707 ** registered the application defined function.
3708 */
3711 /*
3712 ** CAPI3REF: Function Auxiliary Data
3713 **
3714 ** The following two functions may be used by scalar SQL functions to
3715 ** associate metadata with argument values. If the same value is passed to
3716 ** multiple invocations of the same SQL function during query execution, under
3717 ** some circumstances the associated metadata may be preserved. This may
3718 ** be used, for example, to add a regular-expression matching scalar
3719 ** function. The compiled version of the regular expression is stored as
3720 ** metadata associated with the SQL value passed as the regular expression
3721 ** pattern. The compiled regular expression can be reused on multiple
3722 ** invocations of the same function so that the original pattern string
3723 ** does not need to be recompiled on each invocation.
3724 **
3725 ** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata
3726 ** associated by the sqlite3_set_auxdata() function with the Nth argument
3727 ** value to the application-defined function. ^If no metadata has been ever
3728 ** been set for the Nth argument of the function, or if the corresponding
3729 ** function parameter has changed since the meta-data was set,
3730 ** then sqlite3_get_auxdata() returns a NULL pointer.
3731 **
3732 ** ^The sqlite3_set_auxdata() interface saves the metadata
3733 ** pointed to by its 3rd parameter as the metadata for the N-th
3734 ** argument of the application-defined function. Subsequent
3735 ** calls to sqlite3_get_auxdata() might return this data, if it has
3736 ** not been destroyed.
3737 ** ^If it is not NULL, SQLite will invoke the destructor
3738 ** function given by the 4th parameter to sqlite3_set_auxdata() on
3739 ** the metadata when the corresponding function parameter changes
3740 ** or when the SQL statement completes, whichever comes first.
3741 **
3742 ** SQLite is free to call the destructor and drop metadata on any
3743 ** parameter of any function at any time. ^The only guarantee is that
3744 ** the destructor will be called before the metadata is dropped.
3745 **
3746 ** ^(In practice, metadata is preserved between function calls for
3747 ** expressions that are constant at compile time. This includes literal
3748 ** values and [parameters].)^
3749 **
3750 ** These routines must be called from the same thread in which
3751 ** the SQL function is running.
3752 */
3757 /*
3758 ** CAPI3REF: Constants Defining Special Destructor Behavior
3759 **
3760 ** These are special values for the destructor that is passed in as the
3761 ** final argument to routines like [sqlite3_result_blob()]. ^If the destructor
3762 ** argument is SQLITE_STATIC, it means that the content pointer is constant
3763 ** and will never change. It does not need to be destroyed. ^The
3764 ** SQLITE_TRANSIENT value means that the content will likely change in
3765 ** the near future and that SQLite should make its own private copy of
3766 ** the content before returning.
3767 **
3768 ** The typedef is necessary to work around problems in certain
3769 ** C++ compilers. See ticket #2191.
3770 */
3772 #define SQLITE_STATIC ((sqlite3_destructor_type)0)
3773 #define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1)
3775 /*
3776 ** CAPI3REF: Setting The Result Of An SQL Function
3777 **
3778 ** These routines are used by the xFunc or xFinal callbacks that
3779 ** implement SQL functions and aggregates. See
3780 ** [sqlite3_create_function()] and [sqlite3_create_function16()]
3781 ** for additional information.
3782 **
3783 ** These functions work very much like the [parameter binding] family of
3784 ** functions used to bind values to host parameters in prepared statements.
3785 ** Refer to the [SQL parameter] documentation for additional information.
3786 **
3787 ** ^The sqlite3_result_blob() interface sets the result from
3788 ** an application-defined function to be the BLOB whose content is pointed
3789 ** to by the second parameter and which is N bytes long where N is the
3790 ** third parameter.
3791 **
3792 ** ^The sqlite3_result_zeroblob() interfaces set the result of
3793 ** the application-defined function to be a BLOB containing all zero
3794 ** bytes and N bytes in size, where N is the value of the 2nd parameter.
3795 **
3796 ** ^The sqlite3_result_double() interface sets the result from
3797 ** an application-defined function to be a floating point value specified
3798 ** by its 2nd argument.
3799 **
3800 ** ^The sqlite3_result_error() and sqlite3_result_error16() functions
3801 ** cause the implemented SQL function to throw an exception.
3802 ** ^SQLite uses the string pointed to by the
3803 ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
3804 ** as the text of an error message. ^SQLite interprets the error
3805 ** message string from sqlite3_result_error() as UTF-8. ^SQLite
3806 ** interprets the string from sqlite3_result_error16() as UTF-16 in native
3807 ** byte order. ^If the third parameter to sqlite3_result_error()
3808 ** or sqlite3_result_error16() is negative then SQLite takes as the error
3809 ** message all text up through the first zero character.
3810 ** ^If the third parameter to sqlite3_result_error() or
3811 ** sqlite3_result_error16() is non-negative then SQLite takes that many
3812 ** bytes (not characters) from the 2nd parameter as the error message.
3813 ** ^The sqlite3_result_error() and sqlite3_result_error16()
3814 ** routines make a private copy of the error message text before
3815 ** they return. Hence, the calling function can deallocate or
3816 ** modify the text after they return without harm.
3817 ** ^The sqlite3_result_error_code() function changes the error code
3818 ** returned by SQLite as a result of an error in a function. ^By default,
3819 ** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error()
3820 ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
3821 **
3822 ** ^The sqlite3_result_toobig() interface causes SQLite to throw an error
3823 ** indicating that a string or BLOB is too long to represent.
3824 **
3825 ** ^The sqlite3_result_nomem() interface causes SQLite to throw an error
3826 ** indicating that a memory allocation failed.
3827 **
3828 ** ^The sqlite3_result_int() interface sets the return value
3829 ** of the application-defined function to be the 32-bit signed integer
3830 ** value given in the 2nd argument.
3831 ** ^The sqlite3_result_int64() interface sets the return value
3832 ** of the application-defined function to be the 64-bit signed integer
3833 ** value given in the 2nd argument.
3834 **
3835 ** ^The sqlite3_result_null() interface sets the return value
3836 ** of the application-defined function to be NULL.
3837 **
3838 ** ^The sqlite3_result_text(), sqlite3_result_text16(),
3839 ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
3840 ** set the return value of the application-defined function to be
3841 ** a text string which is represented as UTF-8, UTF-16 native byte order,
3842 ** UTF-16 little endian, or UTF-16 big endian, respectively.
3843 ** ^SQLite takes the text result from the application from
3844 ** the 2nd parameter of the sqlite3_result_text* interfaces.
3845 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
3846 ** is negative, then SQLite takes result text from the 2nd parameter
3847 ** through the first zero character.
3848 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
3849 ** is non-negative, then as many bytes (not characters) of the text
3850 ** pointed to by the 2nd parameter are taken as the application-defined
3851 ** function result.
3852 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
3853 ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
3854 ** function as the destructor on the text or BLOB result when it has
3855 ** finished using that result.
3856 ** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
3857 ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
3858 ** assumes that the text or BLOB result is in constant space and does not
3859 ** copy the content of the parameter nor call a destructor on the content
3860 ** when it has finished using that result.
3861 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
3862 ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
3863 ** then SQLite makes a copy of the result into space obtained from
3864 ** from [sqlite3_malloc()] before it returns.
3865 **
3866 ** ^The sqlite3_result_value() interface sets the result of
3867 ** the application-defined function to be a copy the
3868 ** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The
3869 ** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
3870 ** so that the [sqlite3_value] specified in the parameter may change or
3871 ** be deallocated after sqlite3_result_value() returns without harm.
3872 ** ^A [protected sqlite3_value] object may always be used where an
3873 ** [unprotected sqlite3_value] object is required, so either
3874 ** kind of [sqlite3_value] object can be used with this interface.
3875 **
3876 ** If these routines are called from within the different thread
3877 ** than the one containing the application-defined function that received
3878 ** the [sqlite3_context] pointer, the results are undefined.
3879 */
3897 /*
3898 ** CAPI3REF: Define New Collating Sequences
3899 **
3900 ** ^These functions add, remove, or modify a [collation] associated
3901 ** with the [database connection] specified as the first argument.
3902 **
3903 ** ^The name of the collation is a UTF-8 string
3904 ** for sqlite3_create_collation() and sqlite3_create_collation_v2()
3905 ** and a UTF-16 string in native byte order for sqlite3_create_collation16().
3906 ** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
3907 ** considered to be the same name.
3908 **
3909 ** ^(The third argument (eTextRep) must be one of the constants:
3910 ** <ul>
3911 ** <li> [SQLITE_UTF8],
3912 ** <li> [SQLITE_UTF16LE],
3913 ** <li> [SQLITE_UTF16BE],
3914 ** <li> [SQLITE_UTF16], or
3915 ** <li> [SQLITE_UTF16_ALIGNED].
3916 ** </ul>)^
3917 ** ^The eTextRep argument determines the encoding of strings passed
3918 ** to the collating function callback, xCallback.
3919 ** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
3920 ** force strings to be UTF16 with native byte order.
3921 ** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
3922 ** on an even byte address.
3923 **
3924 ** ^The fourth argument, pArg, is an application data pointer that is passed
3925 ** through as the first argument to the collating function callback.
3926 **
3927 ** ^The fifth argument, xCallback, is a pointer to the collating function.
3928 ** ^Multiple collating functions can be registered using the same name but
3929 ** with different eTextRep parameters and SQLite will use whichever
3930 ** function requires the least amount of data transformation.
3931 ** ^If the xCallback argument is NULL then the collating function is
3932 ** deleted. ^When all collating functions having the same name are deleted,
3933 ** that collation is no longer usable.
3934 **
3935 ** ^The collating function callback is invoked with a copy of the pArg
3936 ** application data pointer and with two strings in the encoding specified
3937 ** by the eTextRep argument. The collating function must return an
3938 ** integer that is negative, zero, or positive
3939 ** if the first string is less than, equal to, or greater than the second,
3940 ** respectively. A collating function must always return the same answer
3941 ** given the same inputs. If two or more collating functions are registered
3942 ** to the same collation name (using different eTextRep values) then all
3943 ** must give an equivalent answer when invoked with equivalent strings.
3944 ** The collating function must obey the following properties for all
3945 ** strings A, B, and C:
3946 **
3947 ** <ol>
3948 ** <li> If A==B then B==A.
3949 ** <li> If A==B and B==C then A==C.
3950 ** <li> If A<B THEN B>A.
3951 ** <li> If A<B and B<C then A<C.
3952 ** </ol>
3953 **
3954 ** If a collating function fails any of the above constraints and that
3955 ** collating function is registered and used, then the behavior of SQLite
3956 ** is undefined.
3957 **
3958 ** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
3959 ** with the addition that the xDestroy callback is invoked on pArg when
3960 ** the collating function is deleted.
3961 ** ^Collating functions are deleted when they are overridden by later
3962 ** calls to the collation creation functions or when the
3963 ** [database connection] is closed using [sqlite3_close()].
3964 **
3965 ** ^The xDestroy callback is <u>not</u> called if the
3966 ** sqlite3_create_collation_v2() function fails. Applications that invoke
3967 ** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
3968 ** check the return code and dispose of the application data pointer
3969 ** themselves rather than expecting SQLite to deal with it for them.
3970 ** This is different from every other SQLite interface. The inconsistency
3971 ** is unfortunate but cannot be changed without breaking backwards
3972 ** compatibility.
3973 **
3974 ** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
3975 */
3977 sqlite3*,
3982 );
3984 sqlite3*,
3990 );
3992 sqlite3*,
3997 );
3999 /*
4000 ** CAPI3REF: Collation Needed Callbacks
4001 **
4002 ** ^To avoid having to register all collation sequences before a database
4003 ** can be used, a single callback function may be registered with the
4004 ** [database connection] to be invoked whenever an undefined collation
4005 ** sequence is required.
4006 **
4007 ** ^If the function is registered using the sqlite3_collation_needed() API,
4008 ** then it is passed the names of undefined collation sequences as strings
4009 ** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
4010 ** the names are passed as UTF-16 in machine native byte order.
4011 ** ^A call to either function replaces the existing collation-needed callback.
4012 **
4013 ** ^(When the callback is invoked, the first argument passed is a copy
4014 ** of the second argument to sqlite3_collation_needed() or
4015 ** sqlite3_collation_needed16(). The second argument is the database
4016 ** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
4017 ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
4018 ** sequence function required. The fourth parameter is the name of the
4019 ** required collation sequence.)^
4020 **
4021 ** The callback function should register the desired collation using
4022 ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
4023 ** [sqlite3_create_collation_v2()].
4024 */
4026 sqlite3*,
4029 );
4031 sqlite3*,
4034 );
4036 #ifdef SQLITE_HAS_CODEC
4037 /*
4038 ** Specify the key for an encrypted database. This routine should be
4039 ** called right after sqlite3_open().
4040 **
4041 ** The code to implement this API is not available in the public release
4042 ** of SQLite.
4043 */
4047 );
4049 /*
4050 ** Change the key on an open database. If the current database is not
4051 ** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the
4052 ** database is decrypted.
4053 **
4054 ** The code to implement this API is not available in the public release
4055 ** of SQLite.
4056 */
4060 );
4062 /*
4063 ** Specify the activation key for a SEE database. Unless
4064 ** activated, none of the SEE routines will work.
4065 */
4068 );
4069 #endif
4071 #ifdef SQLITE_ENABLE_CEROD
4072 /*
4073 ** Specify the activation key for a CEROD database. Unless
4074 ** activated, none of the CEROD routines will work.
4075 */
4078 );
4079 #endif
4081 /*
4082 ** CAPI3REF: Suspend Execution For A Short Time
4083 **
4084 ** The sqlite3_sleep() function causes the current thread to suspend execution
4085 ** for at least a number of milliseconds specified in its parameter.
4086 **
4087 ** If the operating system does not support sleep requests with
4088 ** millisecond time resolution, then the time will be rounded up to
4089 ** the nearest second. The number of milliseconds of sleep actually
4090 ** requested from the operating system is returned.
4091 **
4092 ** ^SQLite implements this interface by calling the xSleep()
4093 ** method of the default [sqlite3_vfs] object. If the xSleep() method
4094 ** of the default VFS is not implemented correctly, or not implemented at
4095 ** all, then the behavior of sqlite3_sleep() may deviate from the description
4096 ** in the previous paragraphs.
4097 */
4100 /*
4101 ** CAPI3REF: Name Of The Folder Holding Temporary Files
4102 **
4103 ** ^(If this global variable is made to point to a string which is
4104 ** the name of a folder (a.k.a. directory), then all temporary files
4105 ** created by SQLite when using a built-in [sqlite3_vfs | VFS]
4106 ** will be placed in that directory.)^ ^If this variable
4107 ** is a NULL pointer, then SQLite performs a search for an appropriate
4108 ** temporary file directory.
4109 **
4110 ** It is not safe to read or modify this variable in more than one
4111 ** thread at a time. It is not safe to read or modify this variable
4112 ** if a [database connection] is being used at the same time in a separate
4113 ** thread.
4114 ** It is intended that this variable be set once
4115 ** as part of process initialization and before any SQLite interface
4116 ** routines have been called and that this variable remain unchanged
4117 ** thereafter.
4118 **
4119 ** ^The [temp_store_directory pragma] may modify this variable and cause
4120 ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,
4121 ** the [temp_store_directory pragma] always assumes that any string
4122 ** that this variable points to is held in memory obtained from
4123 ** [sqlite3_malloc] and the pragma may attempt to free that memory
4124 ** using [sqlite3_free].
4125 ** Hence, if this variable is modified directly, either it should be
4126 ** made NULL or made to point to memory obtained from [sqlite3_malloc]
4127 ** or else the use of the [temp_store_directory pragma] should be avoided.
4128 */
4131 /*
4132 ** CAPI3REF: Test For Auto-Commit Mode
4133 ** KEYWORDS: {autocommit mode}
4134 **
4135 ** ^The sqlite3_get_autocommit() interface returns non-zero or
4136 ** zero if the given database connection is or is not in autocommit mode,
4137 ** respectively. ^Autocommit mode is on by default.
4138 ** ^Autocommit mode is disabled by a [BEGIN] statement.
4139 ** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
4140 **
4141 ** If certain kinds of errors occur on a statement within a multi-statement
4142 ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
4143 ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
4144 ** transaction might be rolled back automatically. The only way to
4145 ** find out whether SQLite automatically rolled back the transaction after
4146 ** an error is to use this function.
4147 **
4148 ** If another thread changes the autocommit status of the database
4149 ** connection while this routine is running, then the return value
4150 ** is undefined.
4151 */
4154 /*
4155 ** CAPI3REF: Find The Database Handle Of A Prepared Statement
4156 **
4157 ** ^The sqlite3_db_handle interface returns the [database connection] handle
4158 ** to which a [prepared statement] belongs. ^The [database connection]
4159 ** returned by sqlite3_db_handle is the same [database connection]
4160 ** that was the first argument
4161 ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
4162 ** create the statement in the first place.
4163 */
4166 /*
4167 ** CAPI3REF: Find the next prepared statement
4168 **
4169 ** ^This interface returns a pointer to the next [prepared statement] after
4170 ** pStmt associated with the [database connection] pDb. ^If pStmt is NULL
4171 ** then this interface returns a pointer to the first prepared statement
4172 ** associated with the database connection pDb. ^If no prepared statement
4173 ** satisfies the conditions of this routine, it returns NULL.
4174 **
4175 ** The [database connection] pointer D in a call to
4176 ** [sqlite3_next_stmt(D,S)] must refer to an open database
4177 ** connection and in particular must not be a NULL pointer.
4178 */
4181 /*
4182 ** CAPI3REF: Commit And Rollback Notification Callbacks
4183 **
4184 ** ^The sqlite3_commit_hook() interface registers a callback
4185 ** function to be invoked whenever a transaction is [COMMIT | committed].
4186 ** ^Any callback set by a previous call to sqlite3_commit_hook()
4187 ** for the same database connection is overridden.
4188 ** ^The sqlite3_rollback_hook() interface registers a callback
4189 ** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
4190 ** ^Any callback set by a previous call to sqlite3_rollback_hook()
4191 ** for the same database connection is overridden.
4192 ** ^The pArg argument is passed through to the callback.
4193 ** ^If the callback on a commit hook function returns non-zero,
4194 ** then the commit is converted into a rollback.
4195 **
4196 ** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
4197 ** return the P argument from the previous call of the same function
4198 ** on the same [database connection] D, or NULL for
4199 ** the first call for each function on D.
4200 **
4201 ** The callback implementation must not do anything that will modify
4202 ** the database connection that invoked the callback. Any actions
4203 ** to modify the database connection must be deferred until after the
4204 ** completion of the [sqlite3_step()] call that triggered the commit
4205 ** or rollback hook in the first place.
4206 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
4207 ** database connections for the meaning of "modify" in this paragraph.
4208 **
4209 ** ^Registering a NULL function disables the callback.
4210 **
4211 ** ^When the commit hook callback routine returns zero, the [COMMIT]
4212 ** operation is allowed to continue normally. ^If the commit hook
4213 ** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
4214 ** ^The rollback hook is invoked on a rollback that results from a commit
4215 ** hook returning non-zero, just as it would be with any other rollback.
4216 **
4217 ** ^For the purposes of this API, a transaction is said to have been
4218 ** rolled back if an explicit "ROLLBACK" statement is executed, or
4219 ** an error or constraint causes an implicit rollback to occur.
4220 ** ^The rollback callback is not invoked if a transaction is
4221 ** automatically rolled back because the database connection is closed.
4222 **
4223 ** See also the [sqlite3_update_hook()] interface.
4224 */
4228 /*
4229 ** CAPI3REF: Data Change Notification Callbacks
4230 **
4231 ** ^The sqlite3_update_hook() interface registers a callback function
4232 ** with the [database connection] identified by the first argument
4233 ** to be invoked whenever a row is updated, inserted or deleted.
4234 ** ^Any callback set by a previous call to this function
4235 ** for the same database connection is overridden.
4236 **
4237 ** ^The second argument is a pointer to the function to invoke when a
4238 ** row is updated, inserted or deleted.
4239 ** ^The first argument to the callback is a copy of the third argument
4240 ** to sqlite3_update_hook().
4241 ** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
4242 ** or [SQLITE_UPDATE], depending on the operation that caused the callback
4243 ** to be invoked.
4244 ** ^The third and fourth arguments to the callback contain pointers to the
4245 ** database and table name containing the affected row.
4246 ** ^The final callback parameter is the [rowid] of the row.
4247 ** ^In the case of an update, this is the [rowid] after the update takes place.
4248 **
4249 ** ^(The update hook is not invoked when internal system tables are
4250 ** modified (i.e. sqlite_master and sqlite_sequence).)^
4251 **
4252 ** ^In the current implementation, the update hook
4253 ** is not invoked when duplication rows are deleted because of an
4254 ** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook
4255 ** invoked when rows are deleted using the [truncate optimization].
4256 ** The exceptions defined in this paragraph might change in a future
4257 ** release of SQLite.
4258 **
4259 ** The update hook implementation must not do anything that will modify
4260 ** the database connection that invoked the update hook. Any actions
4261 ** to modify the database connection must be deferred until after the
4262 ** completion of the [sqlite3_step()] call that triggered the update hook.
4263 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
4264 ** database connections for the meaning of "modify" in this paragraph.
4265 **
4266 ** ^The sqlite3_update_hook(D,C,P) function
4267 ** returns the P argument from the previous call
4268 ** on the same [database connection] D, or NULL for
4269 ** the first call on D.
4270 **
4271 ** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()]
4272 ** interfaces.
4273 */
4275 sqlite3*,
4278 );
4280 /*
4281 ** CAPI3REF: Enable Or Disable Shared Pager Cache
4282 ** KEYWORDS: {shared cache}
4283 **
4284 ** ^(This routine enables or disables the sharing of the database cache
4285 ** and schema data structures between [database connection | connections]
4286 ** to the same database. Sharing is enabled if the argument is true
4287 ** and disabled if the argument is false.)^
4288 **
4289 ** ^Cache sharing is enabled and disabled for an entire process.
4290 ** This is a change as of SQLite version 3.5.0. In prior versions of SQLite,
4291 ** sharing was enabled or disabled for each thread separately.
4292 **
4293 ** ^(The cache sharing mode set by this interface effects all subsequent
4294 ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
4295 ** Existing database connections continue use the sharing mode
4296 ** that was in effect at the time they were opened.)^
4297 **
4298 ** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
4299 ** successfully. An [error code] is returned otherwise.)^
4300 **
4301 ** ^Shared cache is disabled by default. But this might change in
4302 ** future releases of SQLite. Applications that care about shared
4303 ** cache setting should set it explicitly.
4304 **
4305 ** See Also: [SQLite Shared-Cache Mode]
4306 */
4309 /*
4310 ** CAPI3REF: Attempt To Free Heap Memory
4311 **
4312 ** ^The sqlite3_release_memory() interface attempts to free N bytes
4313 ** of heap memory by deallocating non-essential memory allocations
4314 ** held by the database library. Memory used to cache database
4315 ** pages to improve performance is an example of non-essential memory.
4316 ** ^sqlite3_release_memory() returns the number of bytes actually freed,
4317 ** which might be more or less than the amount requested.
4318 ** ^The sqlite3_release_memory() routine is a no-op returning zero
4319 ** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
4320 */
4323 /*
4324 ** CAPI3REF: Impose A Limit On Heap Size
4325 **
4326 ** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
4327 ** soft limit on the amount of heap memory that may be allocated by SQLite.
4328 ** ^SQLite strives to keep heap memory utilization below the soft heap
4329 ** limit by reducing the number of pages held in the page cache
4330 ** as heap memory usages approaches the limit.
4331 ** ^The soft heap limit is "soft" because even though SQLite strives to stay
4332 ** below the limit, it will exceed the limit rather than generate
4333 ** an [SQLITE_NOMEM] error. In other words, the soft heap limit
4334 ** is advisory only.
4335 **
4336 ** ^The return value from sqlite3_soft_heap_limit64() is the size of
4337 ** the soft heap limit prior to the call. ^If the argument N is negative
4338 ** then no change is made to the soft heap limit. Hence, the current
4339 ** size of the soft heap limit can be determined by invoking
4340 ** sqlite3_soft_heap_limit64() with a negative argument.
4341 **
4342 ** ^If the argument N is zero then the soft heap limit is disabled.
4343 **
4344 ** ^(The soft heap limit is not enforced in the current implementation
4345 ** if one or more of following conditions are true:
4346 **
4347 ** <ul>
4348 ** <li> The soft heap limit is set to zero.
4349 ** <li> Memory accounting is disabled using a combination of the
4350 ** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
4351 ** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
4352 ** <li> An alternative page cache implementation is specified using
4353 ** [sqlite3_config]([SQLITE_CONFIG_PCACHE],...).
4354 ** <li> The page cache allocates from its own memory pool supplied
4355 ** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
4356 ** from the heap.
4357 ** </ul>)^
4358 **
4359 ** Beginning with SQLite version 3.7.3, the soft heap limit is enforced
4360 ** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT]
4361 ** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT],
4362 ** the soft heap limit is enforced on every memory allocation. Without
4363 ** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced
4364 ** when memory is allocated by the page cache. Testing suggests that because
4365 ** the page cache is the predominate memory user in SQLite, most
4366 ** applications will achieve adequate soft heap limit enforcement without
4367 ** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT].
4368 **
4369 ** The circumstances under which SQLite will enforce the soft heap limit may
4370 ** changes in future releases of SQLite.
4371 */
4374 /*
4375 ** CAPI3REF: Deprecated Soft Heap Limit Interface
4376 ** DEPRECATED
4377 **
4378 ** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
4379 ** interface. This routine is provided for historical compatibility
4380 ** only. All new applications should use the
4381 ** [sqlite3_soft_heap_limit64()] interface rather than this one.
4382 */
4386 /*
4387 ** CAPI3REF: Extract Metadata About A Column Of A Table
4388 **
4389 ** ^This routine returns metadata about a specific column of a specific
4390 ** database table accessible using the [database connection] handle
4391 ** passed as the first function argument.
4392 **
4393 ** ^The column is identified by the second, third and fourth parameters to
4394 ** this function. ^The second parameter is either the name of the database
4395 ** (i.e. "main", "temp", or an attached database) containing the specified
4396 ** table or NULL. ^If it is NULL, then all attached databases are searched
4397 ** for the table using the same algorithm used by the database engine to
4398 ** resolve unqualified table references.
4399 **
4400 ** ^The third and fourth parameters to this function are the table and column
4401 ** name of the desired column, respectively. Neither of these parameters
4402 ** may be NULL.
4403 **
4404 ** ^Metadata is returned by writing to the memory locations passed as the 5th
4405 ** and subsequent parameters to this function. ^Any of these arguments may be
4406 ** NULL, in which case the corresponding element of metadata is omitted.
4407 **
4408 ** ^(<blockquote>
4409 ** <table border="1">
4410 ** <tr><th> Parameter <th> Output<br>Type <th> Description
4411 **
4412 ** <tr><td> 5th <td> const char* <td> Data type
4413 ** <tr><td> 6th <td> const char* <td> Name of default collation sequence
4414 ** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint
4415 ** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY
4416 ** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT]
4417 ** </table>
4418 ** </blockquote>)^
4419 **
4420 ** ^The memory pointed to by the character pointers returned for the
4421 ** declaration type and collation sequence is valid only until the next
4422 ** call to any SQLite API function.
4423 **
4424 ** ^If the specified table is actually a view, an [error code] is returned.
4425 **
4426 ** ^If the specified column is "rowid", "oid" or "_rowid_" and an
4427 ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
4428 ** parameters are set for the explicitly declared column. ^(If there is no
4429 ** explicitly declared [INTEGER PRIMARY KEY] column, then the output
4430 ** parameters are set as follows:
4431 **
4432 ** <pre>
4433 ** data type: "INTEGER"
4434 ** collation sequence: "BINARY"
4435 ** not null: 0
4436 ** primary key: 1
4437 ** auto increment: 0
4438 ** </pre>)^
4439 **
4440 ** ^(This function may load one or more schemas from database files. If an
4441 ** error occurs during this process, or if the requested table or column
4442 ** cannot be found, an [error code] is returned and an error message left
4443 ** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^
4444 **
4445 ** ^This API is only available if the library was compiled with the
4446 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined.
4447 */
4458 );
4460 /*
4461 ** CAPI3REF: Load An Extension
4462 **
4463 ** ^This interface loads an SQLite extension library from the named file.
4464 **
4465 ** ^The sqlite3_load_extension() interface attempts to load an
4466 ** SQLite extension library contained in the file zFile.
4467 **
4468 ** ^The entry point is zProc.
4469 ** ^zProc may be 0, in which case the name of the entry point
4470 ** defaults to "sqlite3_extension_init".
4471 ** ^The sqlite3_load_extension() interface returns
4472 ** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
4473 ** ^If an error occurs and pzErrMsg is not 0, then the
4474 ** [sqlite3_load_extension()] interface shall attempt to
4475 ** fill *pzErrMsg with error message text stored in memory
4476 ** obtained from [sqlite3_malloc()]. The calling function
4477 ** should free this memory by calling [sqlite3_free()].
4478 **
4479 ** ^Extension loading must be enabled using
4480 ** [sqlite3_enable_load_extension()] prior to calling this API,
4481 ** otherwise an error will be returned.
4482 **
4483 ** See also the [load_extension() SQL function].
4484 */
4490 );
4492 /*
4493 ** CAPI3REF: Enable Or Disable Extension Loading
4494 **
4495 ** ^So as not to open security holes in older applications that are
4496 ** unprepared to deal with extension loading, and as a means of disabling
4497 ** extension loading while evaluating user-entered SQL, the following API
4498 ** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
4499 **
4500 ** ^Extension loading is off by default. See ticket #1863.
4501 ** ^Call the sqlite3_enable_load_extension() routine with onoff==1
4502 ** to turn extension loading on and call it with onoff==0 to turn
4503 ** it back off again.
4504 */
4507 /*
4508 ** CAPI3REF: Automatically Load Statically Linked Extensions
4509 **
4510 ** ^This interface causes the xEntryPoint() function to be invoked for
4511 ** each new [database connection] that is created. The idea here is that
4512 ** xEntryPoint() is the entry point for a statically linked SQLite extension
4513 ** that is to be automatically loaded into all new database connections.
4514 **
4515 ** ^(Even though the function prototype shows that xEntryPoint() takes
4516 ** no arguments and returns void, SQLite invokes xEntryPoint() with three
4517 ** arguments and expects and integer result as if the signature of the
4518 ** entry point where as follows:
4519 **
4520 ** <blockquote><pre>
4521 ** int xEntryPoint(
4522 ** sqlite3 *db,
4523 ** const char **pzErrMsg,
4524 ** const struct sqlite3_api_routines *pThunk
4525 ** );
4526 ** </pre></blockquote>)^
4527 **
4528 ** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
4529 ** point to an appropriate error message (obtained from [sqlite3_mprintf()])
4530 ** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg
4531 ** is NULL before calling the xEntryPoint(). ^SQLite will invoke
4532 ** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any
4533 ** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
4534 ** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
4535 **
4536 ** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
4537 ** on the list of automatic extensions is a harmless no-op. ^No entry point
4538 ** will be called more than once for each database connection that is opened.
4539 **
4540 ** See also: [sqlite3_reset_auto_extension()].
4541 */
4544 /*
4545 ** CAPI3REF: Reset Automatic Extension Loading
4546 **
4547 ** ^This interface disables all automatic extensions previously
4548 ** registered using [sqlite3_auto_extension()].
4549 */
4552 /*
4553 ** The interface to the virtual-table mechanism is currently considered
4554 ** to be experimental. The interface might change in incompatible ways.
4555 ** If this is a problem for you, do not use the interface at this time.
4556 **
4557 ** When the virtual-table mechanism stabilizes, we will declare the
4558 ** interface fixed, support it indefinitely, and remove this comment.
4559 */
4561 /*
4562 ** Structures used by the virtual table interface
4563 */
4569 /*
4570 ** CAPI3REF: Virtual Table Object
4571 ** KEYWORDS: sqlite3_module {virtual table module}
4572 **
4573 ** This structure, sometimes called a "virtual table module",
4574 ** defines the implementation of a [virtual tables].
4575 ** This structure consists mostly of methods for the module.
4576 **
4577 ** ^A virtual table module is created by filling in a persistent
4578 ** instance of this structure and passing a pointer to that instance
4579 ** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
4580 ** ^The registration remains valid until it is replaced by a different
4581 ** module or until the [database connection] closes. The content
4582 ** of this structure must not change while it is registered with
4583 ** any database connection.
4584 */
4613 };
4615 /*
4616 ** CAPI3REF: Virtual Table Indexing Information
4617 ** KEYWORDS: sqlite3_index_info
4618 **
4619 ** The sqlite3_index_info structure and its substructures is used as part
4620 ** of the [virtual table] interface to
4621 ** pass information into and receive the reply from the [xBestIndex]
4622 ** method of a [virtual table module]. The fields under **Inputs** are the
4623 ** inputs to xBestIndex and are read-only. xBestIndex inserts its
4624 ** results into the **Outputs** fields.
4625 **
4626 ** ^(The aConstraint[] array records WHERE clause constraints of the form:
4627 **
4628 ** <blockquote>column OP expr</blockquote>
4629 **
4630 ** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is
4631 ** stored in aConstraint[].op using one of the
4632 ** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
4633 ** ^(The index of the column is stored in
4634 ** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the
4635 ** expr on the right-hand side can be evaluated (and thus the constraint
4636 ** is usable) and false if it cannot.)^
4637 **
4638 ** ^The optimizer automatically inverts terms of the form "expr OP column"
4639 ** and makes other simplifications to the WHERE clause in an attempt to
4640 ** get as many WHERE clause terms into the form shown above as possible.
4641 ** ^The aConstraint[] array only reports WHERE clause terms that are
4642 ** relevant to the particular virtual table being queried.
4643 **
4644 ** ^Information about the ORDER BY clause is stored in aOrderBy[].
4645 ** ^Each term of aOrderBy records a column of the ORDER BY clause.
4646 **
4647 ** The [xBestIndex] method must fill aConstraintUsage[] with information
4648 ** about what parameters to pass to xFilter. ^If argvIndex>0 then
4649 ** the right-hand side of the corresponding aConstraint[] is evaluated
4650 ** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit
4651 ** is true, then the constraint is assumed to be fully handled by the
4652 ** virtual table and is not checked again by SQLite.)^
4653 **
4654 ** ^The idxNum and idxPtr values are recorded and passed into the
4655 ** [xFilter] method.
4656 ** ^[sqlite3_free()] is used to free idxPtr if and only if
4657 ** needToFreeIdxPtr is true.
4658 **
4659 ** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
4660 ** the correct order to satisfy the ORDER BY clause so that no separate
4661 ** sorting step is required.
4662 **
4663 ** ^The estimatedCost value is an estimate of the cost of doing the
4664 ** particular lookup. A full scan of a table with N entries should have
4665 ** a cost of N. A binary search of a table of N entries should have a
4666 ** cost of approximately log(N).
4667 */
4669 /* Inputs */
4682 /* Outputs */
4692 };
4694 /*
4695 ** CAPI3REF: Virtual Table Constraint Operator Codes
4696 **
4697 ** These macros defined the allowed values for the
4698 ** [sqlite3_index_info].aConstraint[].op field. Each value represents
4699 ** an operator that is part of a constraint term in the wHERE clause of
4700 ** a query that uses a [virtual table].
4701 */
4702 #define SQLITE_INDEX_CONSTRAINT_EQ 2
4703 #define SQLITE_INDEX_CONSTRAINT_GT 4
4704 #define SQLITE_INDEX_CONSTRAINT_LE 8
4705 #define SQLITE_INDEX_CONSTRAINT_LT 16
4706 #define SQLITE_INDEX_CONSTRAINT_GE 32
4707 #define SQLITE_INDEX_CONSTRAINT_MATCH 64
4709 /*
4710 ** CAPI3REF: Register A Virtual Table Implementation
4711 **
4712 ** ^These routines are used to register a new [virtual table module] name.
4713 ** ^Module names must be registered before
4714 ** creating a new [virtual table] using the module and before using a
4715 ** preexisting [virtual table] for the module.
4716 **
4717 ** ^The module name is registered on the [database connection] specified
4718 ** by the first parameter. ^The name of the module is given by the
4719 ** second parameter. ^The third parameter is a pointer to
4720 ** the implementation of the [virtual table module]. ^The fourth
4721 ** parameter is an arbitrary client data pointer that is passed through
4722 ** into the [xCreate] and [xConnect] methods of the virtual table module
4723 ** when a new virtual table is be being created or reinitialized.
4724 **
4725 ** ^The sqlite3_create_module_v2() interface has a fifth parameter which
4726 ** is a pointer to a destructor for the pClientData. ^SQLite will
4727 ** invoke the destructor function (if it is not NULL) when SQLite
4728 ** no longer needs the pClientData pointer. ^The destructor will also
4729 ** be invoked if the call to sqlite3_create_module_v2() fails.
4730 ** ^The sqlite3_create_module()
4731 ** interface is equivalent to sqlite3_create_module_v2() with a NULL
4732 ** destructor.
4733 */
4739 );
4746 );
4748 /*
4749 ** CAPI3REF: Virtual Table Instance Object
4750 ** KEYWORDS: sqlite3_vtab
4751 **
4752 ** Every [virtual table module] implementation uses a subclass
4753 ** of this object to describe a particular instance
4754 ** of the [virtual table]. Each subclass will
4755 ** be tailored to the specific needs of the module implementation.
4756 ** The purpose of this superclass is to define certain fields that are
4757 ** common to all module implementations.
4758 **
4759 ** ^Virtual tables methods can set an error message by assigning a
4760 ** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should
4761 ** take care that any prior string is freed by a call to [sqlite3_free()]
4762 ** prior to assigning a new string to zErrMsg. ^After the error message
4763 ** is delivered up to the client application, the string will be automatically
4764 ** freed by sqlite3_free() and the zErrMsg field will be zeroed.
4765 */
4770 /* Virtual table implementations will typically add additional fields */
4771 };
4773 /*
4774 ** CAPI3REF: Virtual Table Cursor Object
4775 ** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
4776 **
4777 ** Every [virtual table module] implementation uses a subclass of the
4778 ** following structure to describe cursors that point into the
4779 ** [virtual table] and are used
4780 ** to loop through the virtual table. Cursors are created using the
4781 ** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
4782 ** by the [sqlite3_module.xClose | xClose] method. Cursors are used
4783 ** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
4784 ** of the module. Each module implementation will define
4785 ** the content of a cursor structure to suit its own needs.
4786 **
4787 ** This superclass exists in order to define fields of the cursor that
4788 ** are common to all implementations.
4789 */
4792 /* Virtual table implementations will typically add additional fields */
4793 };
4795 /*
4796 ** CAPI3REF: Declare The Schema Of A Virtual Table
4797 **
4798 ** ^The [xCreate] and [xConnect] methods of a
4799 ** [virtual table module] call this interface
4800 ** to declare the format (the names and datatypes of the columns) of
4801 ** the virtual tables they implement.
4802 */
4805 /*
4806 ** CAPI3REF: Overload A Function For A Virtual Table
4807 **
4808 ** ^(Virtual tables can provide alternative implementations of functions
4809 ** using the [xFindFunction] method of the [virtual table module].
4810 ** But global versions of those functions
4811 ** must exist in order to be overloaded.)^
4812 **
4813 ** ^(This API makes sure a global version of a function with a particular
4814 ** name and number of parameters exists. If no such function exists
4815 ** before this API is called, a new function is created.)^ ^The implementation
4816 ** of the new function always causes an exception to be thrown. So
4817 ** the new function is not good for anything by itself. Its only
4818 ** purpose is to be a placeholder function that can be overloaded
4819 ** by a [virtual table].
4820 */
4823 /*
4824 ** The interface to the virtual-table mechanism defined above (back up
4825 ** to a comment remarkably similar to this one) is currently considered
4826 ** to be experimental. The interface might change in incompatible ways.
4827 ** If this is a problem for you, do not use the interface at this time.
4828 **
4829 ** When the virtual-table mechanism stabilizes, we will declare the
4830 ** interface fixed, support it indefinitely, and remove this comment.
4831 */
4833 /*
4834 ** CAPI3REF: A Handle To An Open BLOB
4835 ** KEYWORDS: {BLOB handle} {BLOB handles}
4836 **
4837 ** An instance of this object represents an open BLOB on which
4838 ** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
4839 ** ^Objects of this type are created by [sqlite3_blob_open()]
4840 ** and destroyed by [sqlite3_blob_close()].
4841 ** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
4842 ** can be used to read or write small subsections of the BLOB.
4843 ** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
4844 */
4847 /*
4848 ** CAPI3REF: Open A BLOB For Incremental I/O
4849 **
4850 ** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
4851 ** in row iRow, column zColumn, table zTable in database zDb;
4852 ** in other words, the same BLOB that would be selected by:
4853 **
4854 ** <pre>
4855 ** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
4856 ** </pre>)^
4857 **
4858 ** ^If the flags parameter is non-zero, then the BLOB is opened for read
4859 ** and write access. ^If it is zero, the BLOB is opened for read access.
4860 ** ^It is not possible to open a column that is part of an index or primary
4861 ** key for writing. ^If [foreign key constraints] are enabled, it is
4862 ** not possible to open a column that is part of a [child key] for writing.
4863 **
4864 ** ^Note that the database name is not the filename that contains
4865 ** the database but rather the symbolic name of the database that
4866 ** appears after the AS keyword when the database is connected using [ATTACH].
4867 ** ^For the main database file, the database name is "main".
4868 ** ^For TEMP tables, the database name is "temp".
4869 **
4870 ** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written
4871 ** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set
4872 ** to be a null pointer.)^
4873 ** ^This function sets the [database connection] error code and message
4874 ** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related
4875 ** functions. ^Note that the *ppBlob variable is always initialized in a
4876 ** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob
4877 ** regardless of the success or failure of this routine.
4878 **
4879 ** ^(If the row that a BLOB handle points to is modified by an
4880 ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
4881 ** then the BLOB handle is marked as "expired".
4882 ** This is true if any column of the row is changed, even a column
4883 ** other than the one the BLOB handle is open on.)^
4884 ** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
4885 ** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
4886 ** ^(Changes written into a BLOB prior to the BLOB expiring are not
4887 ** rolled back by the expiration of the BLOB. Such changes will eventually
4888 ** commit if the transaction continues to completion.)^
4889 **
4890 ** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
4891 ** the opened blob. ^The size of a blob may not be changed by this
4892 ** interface. Use the [UPDATE] SQL command to change the size of a
4893 ** blob.
4894 **
4895 ** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
4896 ** and the built-in [zeroblob] SQL function can be used, if desired,
4897 ** to create an empty, zero-filled blob in which to read or write using
4898 ** this interface.
4899 **
4900 ** To avoid a resource leak, every open [BLOB handle] should eventually
4901 ** be released by a call to [sqlite3_blob_close()].
4902 */
4904 sqlite3*,
4908 sqlite3_int64 iRow,
4910 sqlite3_blob **ppBlob
4911 );
4913 /*
4914 ** CAPI3REF: Move a BLOB Handle to a New Row
4915 **
4916 ** ^This function is used to move an existing blob handle so that it points
4917 ** to a different row of the same database table. ^The new row is identified
4918 ** by the rowid value passed as the second argument. Only the row can be
4919 ** changed. ^The database, table and column on which the blob handle is open
4920 ** remain the same. Moving an existing blob handle to a new row can be
4921 ** faster than closing the existing handle and opening a new one.
4922 **
4923 ** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
4924 ** it must exist and there must be either a blob or text value stored in
4925 ** the nominated column.)^ ^If the new row is not present in the table, or if
4926 ** it does not contain a blob or text value, or if another error occurs, an
4927 ** SQLite error code is returned and the blob handle is considered aborted.
4928 ** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
4929 ** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
4930 ** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
4931 ** always returns zero.
4932 **
4933 ** ^This function sets the database handle error code and message.
4934 */
4937 /*
4938 ** CAPI3REF: Close A BLOB Handle
4939 **
4940 ** ^Closes an open [BLOB handle].
4941 **
4942 ** ^Closing a BLOB shall cause the current transaction to commit
4943 ** if there are no other BLOBs, no pending prepared statements, and the
4944 ** database connection is in [autocommit mode].
4945 ** ^If any writes were made to the BLOB, they might be held in cache
4946 ** until the close operation if they will fit.
4947 **
4948 ** ^(Closing the BLOB often forces the changes
4949 ** out to disk and so if any I/O errors occur, they will likely occur
4950 ** at the time when the BLOB is closed. Any errors that occur during
4951 ** closing are reported as a non-zero return value.)^
4952 **
4953 ** ^(The BLOB is closed unconditionally. Even if this routine returns
4954 ** an error code, the BLOB is still closed.)^
4955 **
4956 ** ^Calling this routine with a null pointer (such as would be returned
4957 ** by a failed call to [sqlite3_blob_open()]) is a harmless no-op.
4958 */
4961 /*
4962 ** CAPI3REF: Return The Size Of An Open BLOB
4963 **
4964 ** ^Returns the size in bytes of the BLOB accessible via the
4965 ** successfully opened [BLOB handle] in its only argument. ^The
4966 ** incremental blob I/O routines can only read or overwriting existing
4967 ** blob content; they cannot change the size of a blob.
4968 **
4969 ** This routine only works on a [BLOB handle] which has been created
4970 ** by a prior successful call to [sqlite3_blob_open()] and which has not
4971 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
4972 ** to this routine results in undefined and probably undesirable behavior.
4973 */
4976 /*
4977 ** CAPI3REF: Read Data From A BLOB Incrementally
4978 **
4979 ** ^(This function is used to read data from an open [BLOB handle] into a
4980 ** caller-supplied buffer. N bytes of data are copied into buffer Z
4981 ** from the open BLOB, starting at offset iOffset.)^
4982 **
4983 ** ^If offset iOffset is less than N bytes from the end of the BLOB,
4984 ** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is
4985 ** less than zero, [SQLITE_ERROR] is returned and no data is read.
4986 ** ^The size of the blob (and hence the maximum value of N+iOffset)
4987 ** can be determined using the [sqlite3_blob_bytes()] interface.
4988 **
4989 ** ^An attempt to read from an expired [BLOB handle] fails with an
4990 ** error code of [SQLITE_ABORT].
4991 **
4992 ** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
4993 ** Otherwise, an [error code] or an [extended error code] is returned.)^
4994 **
4995 ** This routine only works on a [BLOB handle] which has been created
4996 ** by a prior successful call to [sqlite3_blob_open()] and which has not
4997 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
4998 ** to this routine results in undefined and probably undesirable behavior.
4999 **
5000 ** See also: [sqlite3_blob_write()].
5001 */
5004 /*
5005 ** CAPI3REF: Write Data Into A BLOB Incrementally
5006 **
5007 ** ^This function is used to write data into an open [BLOB handle] from a
5008 ** caller-supplied buffer. ^N bytes of data are copied from the buffer Z
5009 ** into the open BLOB, starting at offset iOffset.
5010 **
5011 ** ^If the [BLOB handle] passed as the first argument was not opened for
5012 ** writing (the flags parameter to [sqlite3_blob_open()] was zero),
5013 ** this function returns [SQLITE_READONLY].
5014 **
5015 ** ^This function may only modify the contents of the BLOB; it is
5016 ** not possible to increase the size of a BLOB using this API.
5017 ** ^If offset iOffset is less than N bytes from the end of the BLOB,
5018 ** [SQLITE_ERROR] is returned and no data is written. ^If N is
5019 ** less than zero [SQLITE_ERROR] is returned and no data is written.
5020 ** The size of the BLOB (and hence the maximum value of N+iOffset)
5021 ** can be determined using the [sqlite3_blob_bytes()] interface.
5022 **
5023 ** ^An attempt to write to an expired [BLOB handle] fails with an
5024 ** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred
5025 ** before the [BLOB handle] expired are not rolled back by the
5026 ** expiration of the handle, though of course those changes might
5027 ** have been overwritten by the statement that expired the BLOB handle
5028 ** or by other independent statements.
5029 **
5030 ** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
5031 ** Otherwise, an [error code] or an [extended error code] is returned.)^
5032 **
5033 ** This routine only works on a [BLOB handle] which has been created
5034 ** by a prior successful call to [sqlite3_blob_open()] and which has not
5035 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
5036 ** to this routine results in undefined and probably undesirable behavior.
5037 **
5038 ** See also: [sqlite3_blob_read()].
5039 */
5042 /*
5043 ** CAPI3REF: Virtual File System Objects
5044 **
5045 ** A virtual filesystem (VFS) is an [sqlite3_vfs] object
5046 ** that SQLite uses to interact
5047 ** with the underlying operating system. Most SQLite builds come with a
5048 ** single default VFS that is appropriate for the host computer.
5049 ** New VFSes can be registered and existing VFSes can be unregistered.
5050 ** The following interfaces are provided.
5051 **
5052 ** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
5053 ** ^Names are case sensitive.
5054 ** ^Names are zero-terminated UTF-8 strings.
5055 ** ^If there is no match, a NULL pointer is returned.
5056 ** ^If zVfsName is NULL then the default VFS is returned.
5057 **
5058 ** ^New VFSes are registered with sqlite3_vfs_register().
5059 ** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
5060 ** ^The same VFS can be registered multiple times without injury.
5061 ** ^To make an existing VFS into the default VFS, register it again
5062 ** with the makeDflt flag set. If two different VFSes with the
5063 ** same name are registered, the behavior is undefined. If a
5064 ** VFS is registered with a name that is NULL or an empty string,
5065 ** then the behavior is undefined.
5066 **
5067 ** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
5068 ** ^(If the default VFS is unregistered, another VFS is chosen as
5069 ** the default. The choice for the new VFS is arbitrary.)^
5070 */
5075 /*
5076 ** CAPI3REF: Mutexes
5077 **
5078 ** The SQLite core uses these routines for thread
5079 ** synchronization. Though they are intended for internal
5080 ** use by SQLite, code that links against SQLite is
5081 ** permitted to use any of these routines.
5082 **
5083 ** The SQLite source code contains multiple implementations
5084 ** of these mutex routines. An appropriate implementation
5085 ** is selected automatically at compile-time. ^(The following
5086 ** implementations are available in the SQLite core:
5087 **
5088 ** <ul>
5089 ** <li> SQLITE_MUTEX_OS2
5090 ** <li> SQLITE_MUTEX_PTHREAD
5091 ** <li> SQLITE_MUTEX_W32
5092 ** <li> SQLITE_MUTEX_NOOP
5093 ** </ul>)^
5094 **
5095 ** ^The SQLITE_MUTEX_NOOP implementation is a set of routines
5096 ** that does no real locking and is appropriate for use in
5097 ** a single-threaded application. ^The SQLITE_MUTEX_OS2,
5098 ** SQLITE_MUTEX_PTHREAD, and SQLITE_MUTEX_W32 implementations
5099 ** are appropriate for use on OS/2, Unix, and Windows.
5100 **
5101 ** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
5102 ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
5103 ** implementation is included with the library. In this case the
5104 ** application must supply a custom mutex implementation using the
5105 ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
5106 ** before calling sqlite3_initialize() or any other public sqlite3_
5107 ** function that calls sqlite3_initialize().)^
5108 **
5109 ** ^The sqlite3_mutex_alloc() routine allocates a new
5110 ** mutex and returns a pointer to it. ^If it returns NULL
5111 ** that means that a mutex could not be allocated. ^SQLite
5112 ** will unwind its stack and return an error. ^(The argument
5113 ** to sqlite3_mutex_alloc() is one of these integer constants:
5114 **
5115 ** <ul>
5116 ** <li> SQLITE_MUTEX_FAST
5117 ** <li> SQLITE_MUTEX_RECURSIVE
5118 ** <li> SQLITE_MUTEX_STATIC_MASTER
5119 ** <li> SQLITE_MUTEX_STATIC_MEM
5120 ** <li> SQLITE_MUTEX_STATIC_MEM2
5121 ** <li> SQLITE_MUTEX_STATIC_PRNG
5122 ** <li> SQLITE_MUTEX_STATIC_LRU
5123 ** <li> SQLITE_MUTEX_STATIC_LRU2
5124 ** </ul>)^
5125 **
5126 ** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
5127 ** cause sqlite3_mutex_alloc() to create
5128 ** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
5129 ** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
5130 ** The mutex implementation does not need to make a distinction
5131 ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
5132 ** not want to. ^SQLite will only request a recursive mutex in
5133 ** cases where it really needs one. ^If a faster non-recursive mutex
5134 ** implementation is available on the host platform, the mutex subsystem
5135 ** might return such a mutex in response to SQLITE_MUTEX_FAST.
5136 **
5137 ** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
5138 ** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
5139 ** a pointer to a static preexisting mutex. ^Six static mutexes are
5140 ** used by the current version of SQLite. Future versions of SQLite
5141 ** may add additional static mutexes. Static mutexes are for internal
5142 ** use by SQLite only. Applications that use SQLite mutexes should
5143 ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
5144 ** SQLITE_MUTEX_RECURSIVE.
5145 **
5146 ** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
5147 ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
5148 ** returns a different mutex on every call. ^But for the static
5149 ** mutex types, the same mutex is returned on every call that has
5150 ** the same type number.
5151 **
5152 ** ^The sqlite3_mutex_free() routine deallocates a previously
5153 ** allocated dynamic mutex. ^SQLite is careful to deallocate every
5154 ** dynamic mutex that it allocates. The dynamic mutexes must not be in
5155 ** use when they are deallocated. Attempting to deallocate a static
5156 ** mutex results in undefined behavior. ^SQLite never deallocates
5157 ** a static mutex.
5158 **
5159 ** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
5160 ** to enter a mutex. ^If another thread is already within the mutex,
5161 ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
5162 ** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
5163 ** upon successful entry. ^(Mutexes created using
5164 ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
5165 ** In such cases the,
5166 ** mutex must be exited an equal number of times before another thread
5167 ** can enter.)^ ^(If the same thread tries to enter any other
5168 ** kind of mutex more than once, the behavior is undefined.
5169 ** SQLite will never exhibit
5170 ** such behavior in its own use of mutexes.)^
5171 **
5172 ** ^(Some systems (for example, Windows 95) do not support the operation
5173 ** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try()
5174 ** will always return SQLITE_BUSY. The SQLite core only ever uses
5175 ** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^
5176 **
5177 ** ^The sqlite3_mutex_leave() routine exits a mutex that was
5178 ** previously entered by the same thread. ^(The behavior
5179 ** is undefined if the mutex is not currently entered by the
5180 ** calling thread or is not currently allocated. SQLite will
5181 ** never do either.)^
5182 **
5183 ** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
5184 ** sqlite3_mutex_leave() is a NULL pointer, then all three routines
5185 ** behave as no-ops.
5186 **
5187 ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
5188 */
5195 /*
5196 ** CAPI3REF: Mutex Methods Object
5197 **
5198 ** An instance of this structure defines the low-level routines
5199 ** used to allocate and use mutexes.
5200 **
5201 ** Usually, the default mutex implementations provided by SQLite are
5202 ** sufficient, however the user has the option of substituting a custom
5203 ** implementation for specialized deployments or systems for which SQLite
5204 ** does not provide a suitable implementation. In this case, the user
5205 ** creates and populates an instance of this structure to pass
5206 ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
5207 ** Additionally, an instance of this structure can be used as an
5208 ** output variable when querying the system for the current mutex
5209 ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
5210 **
5211 ** ^The xMutexInit method defined by this structure is invoked as
5212 ** part of system initialization by the sqlite3_initialize() function.
5213 ** ^The xMutexInit routine is called by SQLite exactly once for each
5214 ** effective call to [sqlite3_initialize()].
5215 **
5216 ** ^The xMutexEnd method defined by this structure is invoked as
5217 ** part of system shutdown by the sqlite3_shutdown() function. The
5218 ** implementation of this method is expected to release all outstanding
5219 ** resources obtained by the mutex methods implementation, especially
5220 ** those obtained by the xMutexInit method. ^The xMutexEnd()
5221 ** interface is invoked exactly once for each call to [sqlite3_shutdown()].
5222 **
5223 ** ^(The remaining seven methods defined by this structure (xMutexAlloc,
5224 ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
5225 ** xMutexNotheld) implement the following interfaces (respectively):
5226 **
5227 ** <ul>
5228 ** <li> [sqlite3_mutex_alloc()] </li>
5229 ** <li> [sqlite3_mutex_free()] </li>
5230 ** <li> [sqlite3_mutex_enter()] </li>
5231 ** <li> [sqlite3_mutex_try()] </li>
5232 ** <li> [sqlite3_mutex_leave()] </li>
5233 ** <li> [sqlite3_mutex_held()] </li>
5234 ** <li> [sqlite3_mutex_notheld()] </li>
5235 ** </ul>)^
5236 **
5237 ** The only difference is that the public sqlite3_XXX functions enumerated
5238 ** above silently ignore any invocations that pass a NULL pointer instead
5239 ** of a valid mutex handle. The implementations of the methods defined
5240 ** by this structure are not required to handle this case, the results
5241 ** of passing a NULL pointer instead of a valid mutex handle are undefined
5242 ** (i.e. it is acceptable to provide an implementation that segfaults if
5243 ** it is passed a NULL pointer).
5244 **
5245 ** The xMutexInit() method must be threadsafe. ^It must be harmless to
5246 ** invoke xMutexInit() multiple times within the same process and without
5247 ** intervening calls to xMutexEnd(). Second and subsequent calls to
5248 ** xMutexInit() must be no-ops.
5249 **
5250 ** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
5251 ** and its associates). ^Similarly, xMutexAlloc() must not use SQLite memory
5252 ** allocation for a static mutex. ^However xMutexAlloc() may use SQLite
5253 ** memory allocation for a fast or recursive mutex.
5254 **
5255 ** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
5256 ** called, but only if the prior call to xMutexInit returned SQLITE_OK.
5257 ** If xMutexInit fails in any way, it is expected to clean up after itself
5258 ** prior to returning.
5259 */
5271 };
5273 /*
5274 ** CAPI3REF: Mutex Verification Routines
5275 **
5276 ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
5277 ** are intended for use inside assert() statements. ^The SQLite core
5278 ** never uses these routines except inside an assert() and applications
5279 ** are advised to follow the lead of the core. ^The SQLite core only
5280 ** provides implementations for these routines when it is compiled
5281 ** with the SQLITE_DEBUG flag. ^External mutex implementations
5282 ** are only required to provide these routines if SQLITE_DEBUG is
5283 ** defined and if NDEBUG is not defined.
5284 **
5285 ** ^These routines should return true if the mutex in their argument
5286 ** is held or not held, respectively, by the calling thread.
5287 **
5288 ** ^The implementation is not required to provided versions of these
5289 ** routines that actually work. If the implementation does not provide working
5290 ** versions of these routines, it should at least provide stubs that always
5291 ** return true so that one does not get spurious assertion failures.
5292 **
5293 ** ^If the argument to sqlite3_mutex_held() is a NULL pointer then
5294 ** the routine should return 1. This seems counter-intuitive since
5295 ** clearly the mutex cannot be held if it does not exist. But the
5296 ** the reason the mutex does not exist is because the build is not
5297 ** using mutexes. And we do not want the assert() containing the
5298 ** call to sqlite3_mutex_held() to fail, so a non-zero return is
5299 ** the appropriate thing to do. ^The sqlite3_mutex_notheld()
5300 ** interface should also return 1 when given a NULL pointer.
5301 */
5302 #ifndef NDEBUG
5305 #endif
5307 /*
5308 ** CAPI3REF: Mutex Types
5309 **
5310 ** The [sqlite3_mutex_alloc()] interface takes a single argument
5311 ** which is one of these integer constants.
5312 **
5313 ** The set of static mutexes may change from one SQLite release to the
5314 ** next. Applications that override the built-in mutex logic must be
5315 ** prepared to accommodate additional static mutexes.
5316 */
5317 #define SQLITE_MUTEX_FAST 0
5318 #define SQLITE_MUTEX_RECURSIVE 1
5319 #define SQLITE_MUTEX_STATIC_MASTER 2
5328 /*
5329 ** CAPI3REF: Retrieve the mutex for a database connection
5330 **
5331 ** ^This interface returns a pointer the [sqlite3_mutex] object that
5332 ** serializes access to the [database connection] given in the argument
5333 ** when the [threading mode] is Serialized.
5334 ** ^If the [threading mode] is Single-thread or Multi-thread then this
5335 ** routine returns a NULL pointer.
5336 */
5339 /*
5340 ** CAPI3REF: Low-Level Control Of Database Files
5341 **
5342 ** ^The [sqlite3_file_control()] interface makes a direct call to the
5343 ** xFileControl method for the [sqlite3_io_methods] object associated
5344 ** with a particular database identified by the second argument. ^The
5345 ** name of the database is "main" for the main database or "temp" for the
5346 ** TEMP database, or the name that appears after the AS keyword for
5347 ** databases that are added using the [ATTACH] SQL command.
5348 ** ^A NULL pointer can be used in place of "main" to refer to the
5349 ** main database file.
5350 ** ^The third and fourth parameters to this routine
5351 ** are passed directly through to the second and third parameters of
5352 ** the xFileControl method. ^The return value of the xFileControl
5353 ** method becomes the return value of this routine.
5354 **
5355 ** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes
5356 ** a pointer to the underlying [sqlite3_file] object to be written into
5357 ** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER
5358 ** case is a short-circuit path which does not actually invoke the
5359 ** underlying sqlite3_io_methods.xFileControl method.
5360 **
5361 ** ^If the second parameter (zDbName) does not match the name of any
5362 ** open database file, then SQLITE_ERROR is returned. ^This error
5363 ** code is not remembered and will not be recalled by [sqlite3_errcode()]
5364 ** or [sqlite3_errmsg()]. The underlying xFileControl method might
5365 ** also return SQLITE_ERROR. There is no way to distinguish between
5366 ** an incorrect zDbName and an SQLITE_ERROR return from the underlying
5367 ** xFileControl method.
5368 **
5369 ** See also: [SQLITE_FCNTL_LOCKSTATE]
5370 */
5373 /*
5374 ** CAPI3REF: Testing Interface
5375 **
5376 ** ^The sqlite3_test_control() interface is used to read out internal
5377 ** state of SQLite and to inject faults into SQLite for testing
5378 ** purposes. ^The first parameter is an operation code that determines
5379 ** the number, meaning, and operation of all subsequent parameters.
5380 **
5381 ** This interface is not for use by applications. It exists solely
5382 ** for verifying the correct operation of the SQLite library. Depending
5383 ** on how the SQLite library is compiled, this interface might not exist.
5384 **
5385 ** The details of the operation codes, their meanings, the parameters
5386 ** they take, and what they do are all subject to change without notice.
5387 ** Unlike most of the SQLite API, this function is not guaranteed to
5388 ** operate consistently from one release to the next.
5389 */
5392 /*
5393 ** CAPI3REF: Testing Interface Operation Codes
5394 **
5395 ** These constants are the valid operation code parameters used
5396 ** as the first argument to [sqlite3_test_control()].
5397 **
5398 ** These parameters and their meanings are subject to change
5399 ** without notice. These values are for testing purposes only.
5400 ** Applications should not use any of these parameters or the
5401 ** [sqlite3_test_control()] interface.
5402 */
5403 #define SQLITE_TESTCTRL_FIRST 5
5404 #define SQLITE_TESTCTRL_PRNG_SAVE 5
5405 #define SQLITE_TESTCTRL_PRNG_RESTORE 6
5406 #define SQLITE_TESTCTRL_PRNG_RESET 7
5407 #define SQLITE_TESTCTRL_BITVEC_TEST 8
5408 #define SQLITE_TESTCTRL_FAULT_INSTALL 9
5409 #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10
5410 #define SQLITE_TESTCTRL_PENDING_BYTE 11
5411 #define SQLITE_TESTCTRL_ASSERT 12
5412 #define SQLITE_TESTCTRL_ALWAYS 13
5413 #define SQLITE_TESTCTRL_RESERVE 14
5414 #define SQLITE_TESTCTRL_OPTIMIZATIONS 15
5415 #define SQLITE_TESTCTRL_ISKEYWORD 16
5416 #define SQLITE_TESTCTRL_PGHDRSZ 17
5417 #define SQLITE_TESTCTRL_SCRATCHMALLOC 18
5418 #define SQLITE_TESTCTRL_LAST 18
5420 /*
5421 ** CAPI3REF: SQLite Runtime Status
5422 **
5423 ** ^This interface is used to retrieve runtime status information
5424 ** about the performance of SQLite, and optionally to reset various
5425 ** highwater marks. ^The first argument is an integer code for
5426 ** the specific parameter to measure. ^(Recognized integer codes
5427 ** are of the form [SQLITE_STATUS_MEMORY_USED | SQLITE_STATUS_...].)^
5428 ** ^The current value of the parameter is returned into *pCurrent.
5429 ** ^The highest recorded value is returned in *pHighwater. ^If the
5430 ** resetFlag is true, then the highest record value is reset after
5431 ** *pHighwater is written. ^(Some parameters do not record the highest
5432 ** value. For those parameters
5433 ** nothing is written into *pHighwater and the resetFlag is ignored.)^
5434 ** ^(Other parameters record only the highwater mark and not the current
5435 ** value. For these latter parameters nothing is written into *pCurrent.)^
5436 **
5437 ** ^The sqlite3_status() routine returns SQLITE_OK on success and a
5438 ** non-zero [error code] on failure.
5439 **
5440 ** This routine is threadsafe but is not atomic. This routine can be
5441 ** called while other threads are running the same or different SQLite
5442 ** interfaces. However the values returned in *pCurrent and
5443 ** *pHighwater reflect the status of SQLite at different points in time
5444 ** and it is possible that another thread might change the parameter
5445 ** in between the times when *pCurrent and *pHighwater are written.
5446 **
5447 ** See also: [sqlite3_db_status()]
5448 */
5452 /*
5453 ** CAPI3REF: Status Parameters
5454 **
5455 ** These integer constants designate various run-time status parameters
5456 ** that can be returned by [sqlite3_status()].
5457 **
5458 ** <dl>
5459 ** ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
5460 ** <dd>This parameter is the current amount of memory checked out
5461 ** using [sqlite3_malloc()], either directly or indirectly. The
5462 ** figure includes calls made to [sqlite3_malloc()] by the application
5463 ** and internal memory usage by the SQLite library. Scratch memory
5464 ** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache
5465 ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
5466 ** this parameter. The amount returned is the sum of the allocation
5467 ** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
5468 **
5469 ** ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
5470 ** <dd>This parameter records the largest memory allocation request
5471 ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
5472 ** internal equivalents). Only the value returned in the
5473 ** *pHighwater parameter to [sqlite3_status()] is of interest.
5474 ** The value written into the *pCurrent parameter is undefined.</dd>)^
5475 **
5476 ** ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
5477 ** <dd>This parameter records the number of separate memory allocations
5478 ** currently checked out.</dd>)^
5479 **
5480 ** ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
5481 ** <dd>This parameter returns the number of pages used out of the
5482 ** [pagecache memory allocator] that was configured using
5483 ** [SQLITE_CONFIG_PAGECACHE]. The
5484 ** value returned is in pages, not in bytes.</dd>)^
5485 **
5486 ** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
5487 ** <dd>This parameter returns the number of bytes of page cache
5488 ** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
5489 ** buffer and where forced to overflow to [sqlite3_malloc()]. The
5490 ** returned value includes allocations that overflowed because they
5491 ** where too large (they were larger than the "sz" parameter to
5492 ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
5493 ** no space was left in the page cache.</dd>)^
5494 **
5495 ** ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
5496 ** <dd>This parameter records the largest memory allocation request
5497 ** handed to [pagecache memory allocator]. Only the value returned in the
5498 ** *pHighwater parameter to [sqlite3_status()] is of interest.
5499 ** The value written into the *pCurrent parameter is undefined.</dd>)^
5500 **
5501 ** ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt>
5502 ** <dd>This parameter returns the number of allocations used out of the
5503 ** [scratch memory allocator] configured using
5504 ** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not
5505 ** in bytes. Since a single thread may only have one scratch allocation
5506 ** outstanding at time, this parameter also reports the number of threads
5507 ** using scratch memory at the same time.</dd>)^
5508 **
5509 ** ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
5510 ** <dd>This parameter returns the number of bytes of scratch memory
5511 ** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH]
5512 ** buffer and where forced to overflow to [sqlite3_malloc()]. The values
5513 ** returned include overflows because the requested allocation was too
5514 ** larger (that is, because the requested allocation was larger than the
5515 ** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer
5516 ** slots were available.
5517 ** </dd>)^
5518 **
5519 ** ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
5520 ** <dd>This parameter records the largest memory allocation request
5521 ** handed to [scratch memory allocator]. Only the value returned in the
5522 ** *pHighwater parameter to [sqlite3_status()] is of interest.
5523 ** The value written into the *pCurrent parameter is undefined.</dd>)^
5524 **
5525 ** ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
5526 ** <dd>This parameter records the deepest parser stack. It is only
5527 ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
5528 ** </dl>
5529 **
5530 ** New status parameters may be added from time to time.
5531 */
5532 #define SQLITE_STATUS_MEMORY_USED 0
5533 #define SQLITE_STATUS_PAGECACHE_USED 1
5534 #define SQLITE_STATUS_PAGECACHE_OVERFLOW 2
5535 #define SQLITE_STATUS_SCRATCH_USED 3
5536 #define SQLITE_STATUS_SCRATCH_OVERFLOW 4
5537 #define SQLITE_STATUS_MALLOC_SIZE 5
5538 #define SQLITE_STATUS_PARSER_STACK 6
5539 #define SQLITE_STATUS_PAGECACHE_SIZE 7
5540 #define SQLITE_STATUS_SCRATCH_SIZE 8
5541 #define SQLITE_STATUS_MALLOC_COUNT 9
5543 /*
5544 ** CAPI3REF: Database Connection Status
5545 **
5546 ** ^This interface is used to retrieve runtime status information
5547 ** about a single [database connection]. ^The first argument is the
5548 ** database connection object to be interrogated. ^The second argument
5549 ** is an integer constant, taken from the set of
5550 ** [SQLITE_DBSTATUS_LOOKASIDE_USED | SQLITE_DBSTATUS_*] macros, that
5551 ** determines the parameter to interrogate. The set of
5552 ** [SQLITE_DBSTATUS_LOOKASIDE_USED | SQLITE_DBSTATUS_*] macros is likely
5553 ** to grow in future releases of SQLite.
5554 **
5555 ** ^The current value of the requested parameter is written into *pCur
5556 ** and the highest instantaneous value is written into *pHiwtr. ^If
5557 ** the resetFlg is true, then the highest instantaneous value is
5558 ** reset back down to the current value.
5559 **
5560 ** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
5561 ** non-zero [error code] on failure.
5562 **
5563 ** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
5564 */
5567 /*
5568 ** CAPI3REF: Status Parameters for database connections
5569 **
5570 ** These constants are the available integer "verbs" that can be passed as
5571 ** the second argument to the [sqlite3_db_status()] interface.
5572 **
5573 ** New verbs may be added in future releases of SQLite. Existing verbs
5574 ** might be discontinued. Applications should check the return code from
5575 ** [sqlite3_db_status()] to make sure that the call worked.
5576 ** The [sqlite3_db_status()] interface will return a non-zero error code
5577 ** if a discontinued or unsupported verb is invoked.
5578 **
5579 ** <dl>
5580 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
5581 ** <dd>This parameter returns the number of lookaside memory slots currently
5582 ** checked out.</dd>)^
5583 **
5584 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
5585 ** <dd>This parameter returns the number malloc attempts that were
5586 ** satisfied using lookaside memory. Only the high-water value is meaningful;
5587 ** the current value is always zero.)^
5588 **
5589 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
5590 ** <dd>This parameter returns the number malloc attempts that might have
5591 ** been satisfied using lookaside memory but failed due to the amount of
5592 ** memory requested being larger than the lookaside slot size.
5593 ** Only the high-water value is meaningful;
5594 ** the current value is always zero.)^
5595 **
5596 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
5597 ** <dd>This parameter returns the number malloc attempts that might have
5598 ** been satisfied using lookaside memory but failed due to all lookaside
5599 ** memory already being in use.
5600 ** Only the high-water value is meaningful;
5601 ** the current value is always zero.)^
5602 **
5603 ** ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
5604 ** <dd>This parameter returns the approximate number of of bytes of heap
5605 ** memory used by all pager caches associated with the database connection.)^
5606 ** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
5607 **
5608 ** ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
5609 ** <dd>This parameter returns the approximate number of of bytes of heap
5610 ** memory used to store the schema for all databases associated
5611 ** with the connection - main, temp, and any [ATTACH]-ed databases.)^
5612 ** ^The full amount of memory used by the schemas is reported, even if the
5613 ** schema memory is shared with other database connections due to
5614 ** [shared cache mode] being enabled.
5615 ** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
5616 **
5617 ** ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
5618 ** <dd>This parameter returns the approximate number of of bytes of heap
5619 ** and lookaside memory used by all prepared statements associated with
5620 ** the database connection.)^
5621 ** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
5622 ** </dd>
5623 ** </dl>
5624 */
5625 #define SQLITE_DBSTATUS_LOOKASIDE_USED 0
5626 #define SQLITE_DBSTATUS_CACHE_USED 1
5627 #define SQLITE_DBSTATUS_SCHEMA_USED 2
5628 #define SQLITE_DBSTATUS_STMT_USED 3
5629 #define SQLITE_DBSTATUS_LOOKASIDE_HIT 4
5630 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5
5631 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6
5635 /*
5636 ** CAPI3REF: Prepared Statement Status
5637 **
5638 ** ^(Each prepared statement maintains various
5639 ** [SQLITE_STMTSTATUS_SORT | counters] that measure the number
5640 ** of times it has performed specific operations.)^ These counters can
5641 ** be used to monitor the performance characteristics of the prepared
5642 ** statements. For example, if the number of table steps greatly exceeds
5643 ** the number of table searches or result rows, that would tend to indicate
5644 ** that the prepared statement is using a full table scan rather than
5645 ** an index.
5646 **
5647 ** ^(This interface is used to retrieve and reset counter values from
5648 ** a [prepared statement]. The first argument is the prepared statement
5649 ** object to be interrogated. The second argument
5650 ** is an integer code for a specific [SQLITE_STMTSTATUS_SORT | counter]
5651 ** to be interrogated.)^
5652 ** ^The current value of the requested counter is returned.
5653 ** ^If the resetFlg is true, then the counter is reset to zero after this
5654 ** interface call returns.
5655 **
5656 ** See also: [sqlite3_status()] and [sqlite3_db_status()].
5657 */
5660 /*
5661 ** CAPI3REF: Status Parameters for prepared statements
5662 **
5663 ** These preprocessor macros define integer codes that name counter
5664 ** values associated with the [sqlite3_stmt_status()] interface.
5665 ** The meanings of the various counters are as follows:
5666 **
5667 ** <dl>
5668 ** <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
5669 ** <dd>^This is the number of times that SQLite has stepped forward in
5670 ** a table as part of a full table scan. Large numbers for this counter
5671 ** may indicate opportunities for performance improvement through
5672 ** careful use of indices.</dd>
5673 **
5674 ** <dt>SQLITE_STMTSTATUS_SORT</dt>
5675 ** <dd>^This is the number of sort operations that have occurred.
5676 ** A non-zero value in this counter may indicate an opportunity to
5677 ** improvement performance through careful use of indices.</dd>
5678 **
5679 ** <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
5680 ** <dd>^This is the number of rows inserted into transient indices that
5681 ** were created automatically in order to help joins run faster.
5682 ** A non-zero value in this counter may indicate an opportunity to
5683 ** improvement performance by adding permanent indices that do not
5684 ** need to be reinitialized each time the statement is run.</dd>
5685 **
5686 ** </dl>
5687 */
5688 #define SQLITE_STMTSTATUS_FULLSCAN_STEP 1
5689 #define SQLITE_STMTSTATUS_SORT 2
5690 #define SQLITE_STMTSTATUS_AUTOINDEX 3
5692 /*
5693 ** CAPI3REF: Custom Page Cache Object
5694 **
5695 ** The sqlite3_pcache type is opaque. It is implemented by
5696 ** the pluggable module. The SQLite core has no knowledge of
5697 ** its size or internal structure and never deals with the
5698 ** sqlite3_pcache object except by holding and passing pointers
5699 ** to the object.
5700 **
5701 ** See [sqlite3_pcache_methods] for additional information.
5702 */
5705 /*
5706 ** CAPI3REF: Application Defined Page Cache.
5707 ** KEYWORDS: {page cache}
5708 **
5709 ** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE], ...) interface can
5710 ** register an alternative page cache implementation by passing in an
5711 ** instance of the sqlite3_pcache_methods structure.)^
5712 ** In many applications, most of the heap memory allocated by
5713 ** SQLite is used for the page cache.
5714 ** By implementing a
5715 ** custom page cache using this API, an application can better control
5716 ** the amount of memory consumed by SQLite, the way in which
5717 ** that memory is allocated and released, and the policies used to
5718 ** determine exactly which parts of a database file are cached and for
5719 ** how long.
5720 **
5721 ** The alternative page cache mechanism is an
5722 ** extreme measure that is only needed by the most demanding applications.
5723 ** The built-in page cache is recommended for most uses.
5724 **
5725 ** ^(The contents of the sqlite3_pcache_methods structure are copied to an
5726 ** internal buffer by SQLite within the call to [sqlite3_config]. Hence
5727 ** the application may discard the parameter after the call to
5728 ** [sqlite3_config()] returns.)^
5729 **
5730 ** ^(The xInit() method is called once for each effective
5731 ** call to [sqlite3_initialize()])^
5732 ** (usually only once during the lifetime of the process). ^(The xInit()
5733 ** method is passed a copy of the sqlite3_pcache_methods.pArg value.)^
5734 ** The intent of the xInit() method is to set up global data structures
5735 ** required by the custom page cache implementation.
5736 ** ^(If the xInit() method is NULL, then the
5737 ** built-in default page cache is used instead of the application defined
5738 ** page cache.)^
5739 **
5740 ** ^The xShutdown() method is called by [sqlite3_shutdown()].
5741 ** It can be used to clean up
5742 ** any outstanding resources before process shutdown, if required.
5743 ** ^The xShutdown() method may be NULL.
5744 **
5745 ** ^SQLite automatically serializes calls to the xInit method,
5746 ** so the xInit method need not be threadsafe. ^The
5747 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
5748 ** not need to be threadsafe either. All other methods must be threadsafe
5749 ** in multithreaded applications.
5750 **
5751 ** ^SQLite will never invoke xInit() more than once without an intervening
5752 ** call to xShutdown().
5753 **
5754 ** ^SQLite invokes the xCreate() method to construct a new cache instance.
5755 ** SQLite will typically create one cache instance for each open database file,
5756 ** though this is not guaranteed. ^The
5757 ** first parameter, szPage, is the size in bytes of the pages that must
5758 ** be allocated by the cache. ^szPage will not be a power of two. ^szPage
5759 ** will the page size of the database file that is to be cached plus an
5760 ** increment (here called "R") of less than 250. SQLite will use the
5761 ** extra R bytes on each page to store metadata about the underlying
5762 ** database page on disk. The value of R depends
5763 ** on the SQLite version, the target platform, and how SQLite was compiled.
5764 ** ^(R is constant for a particular build of SQLite. Except, there are two
5765 ** distinct values of R when SQLite is compiled with the proprietary
5766 ** ZIPVFS extension.)^ ^The second argument to
5767 ** xCreate(), bPurgeable, is true if the cache being created will
5768 ** be used to cache database pages of a file stored on disk, or
5769 ** false if it is used for an in-memory database. The cache implementation
5770 ** does not have to do anything special based with the value of bPurgeable;
5771 ** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will
5772 ** never invoke xUnpin() except to deliberately delete a page.
5773 ** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
5774 ** false will always have the "discard" flag set to true.
5775 ** ^Hence, a cache created with bPurgeable false will
5776 ** never contain any unpinned pages.
5777 **
5778 ** ^(The xCachesize() method may be called at any time by SQLite to set the
5779 ** suggested maximum cache-size (number of pages stored by) the cache
5780 ** instance passed as the first argument. This is the value configured using
5781 ** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable
5782 ** parameter, the implementation is not required to do anything with this
5783 ** value; it is advisory only.
5784 **
5785 ** The xPagecount() method must return the number of pages currently
5786 ** stored in the cache, both pinned and unpinned.
5787 **
5788 ** The xFetch() method locates a page in the cache and returns a pointer to
5789 ** the page, or a NULL pointer.
5790 ** A "page", in this context, means a buffer of szPage bytes aligned at an
5791 ** 8-byte boundary. The page to be fetched is determined by the key. ^The
5792 ** mimimum key value is 1. After it has been retrieved using xFetch, the page
5793 ** is considered to be "pinned".
5794 **
5795 ** If the requested page is already in the page cache, then the page cache
5796 ** implementation must return a pointer to the page buffer with its content
5797 ** intact. If the requested page is not already in the cache, then the
5798 ** cache implementation should use the value of the createFlag
5799 ** parameter to help it determined what action to take:
5800 **
5801 ** <table border=1 width=85% align=center>
5802 ** <tr><th> createFlag <th> Behaviour when page is not already in cache
5803 ** <tr><td> 0 <td> Do not allocate a new page. Return NULL.
5804 ** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
5805 ** Otherwise return NULL.
5806 ** <tr><td> 2 <td> Make every effort to allocate a new page. Only return
5807 ** NULL if allocating a new page is effectively impossible.
5808 ** </table>
5809 **
5810 ** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite
5811 ** will only use a createFlag of 2 after a prior call with a createFlag of 1
5812 ** failed.)^ In between the to xFetch() calls, SQLite may
5813 ** attempt to unpin one or more cache pages by spilling the content of
5814 ** pinned pages to disk and synching the operating system disk cache.
5815 **
5816 ** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
5817 ** as its second argument. If the third parameter, discard, is non-zero,
5818 ** then the page must be evicted from the cache.
5819 ** ^If the discard parameter is
5820 ** zero, then the page may be discarded or retained at the discretion of
5821 ** page cache implementation. ^The page cache implementation
5822 ** may choose to evict unpinned pages at any time.
5823 **
5824 ** The cache must not perform any reference counting. A single
5825 ** call to xUnpin() unpins the page regardless of the number of prior calls
5826 ** to xFetch().
5827 **
5828 ** The xRekey() method is used to change the key value associated with the
5829 ** page passed as the second argument. If the cache
5830 ** previously contains an entry associated with newKey, it must be
5831 ** discarded. ^Any prior cache entry associated with newKey is guaranteed not
5832 ** to be pinned.
5833 **
5834 ** When SQLite calls the xTruncate() method, the cache must discard all
5835 ** existing cache entries with page numbers (keys) greater than or equal
5836 ** to the value of the iLimit parameter passed to xTruncate(). If any
5837 ** of these pages are pinned, they are implicitly unpinned, meaning that
5838 ** they can be safely discarded.
5839 **
5840 ** ^The xDestroy() method is used to delete a cache allocated by xCreate().
5841 ** All resources associated with the specified cache should be freed. ^After
5842 ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
5843 ** handle invalid, and will not use it with any other sqlite3_pcache_methods
5844 ** functions.
5845 */
5859 };
5861 /*
5862 ** CAPI3REF: Online Backup Object
5863 **
5864 ** The sqlite3_backup object records state information about an ongoing
5865 ** online backup operation. ^The sqlite3_backup object is created by
5866 ** a call to [sqlite3_backup_init()] and is destroyed by a call to
5867 ** [sqlite3_backup_finish()].
5868 **
5869 ** See Also: [Using the SQLite Online Backup API]
5870 */
5873 /*
5874 ** CAPI3REF: Online Backup API.
5875 **
5876 ** The backup API copies the content of one database into another.
5877 ** It is useful either for creating backups of databases or
5878 ** for copying in-memory databases to or from persistent files.
5879 **
5880 ** See Also: [Using the SQLite Online Backup API]
5881 **
5882 ** ^SQLite holds a write transaction open on the destination database file
5883 ** for the duration of the backup operation.
5884 ** ^The source database is read-locked only while it is being read;
5885 ** it is not locked continuously for the entire backup operation.
5886 ** ^Thus, the backup may be performed on a live source database without
5887 ** preventing other database connections from
5888 ** reading or writing to the source database while the backup is underway.
5889 **
5890 ** ^(To perform a backup operation:
5891 ** <ol>
5892 ** <li><b>sqlite3_backup_init()</b> is called once to initialize the
5893 ** backup,
5894 ** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
5895 ** the data between the two databases, and finally
5896 ** <li><b>sqlite3_backup_finish()</b> is called to release all resources
5897 ** associated with the backup operation.
5898 ** </ol>)^
5899 ** There should be exactly one call to sqlite3_backup_finish() for each
5900 ** successful call to sqlite3_backup_init().
5901 **
5902 ** <b>sqlite3_backup_init()</b>
5903 **
5904 ** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
5905 ** [database connection] associated with the destination database
5906 ** and the database name, respectively.
5907 ** ^The database name is "main" for the main database, "temp" for the
5908 ** temporary database, or the name specified after the AS keyword in
5909 ** an [ATTACH] statement for an attached database.
5910 ** ^The S and M arguments passed to
5911 ** sqlite3_backup_init(D,N,S,M) identify the [database connection]
5912 ** and database name of the source database, respectively.
5913 ** ^The source and destination [database connections] (parameters S and D)
5914 ** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
5915 ** an error.
5916 **
5917 ** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
5918 ** returned and an error code and error message are stored in the
5919 ** destination [database connection] D.
5920 ** ^The error code and message for the failed call to sqlite3_backup_init()
5921 ** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
5922 ** [sqlite3_errmsg16()] functions.
5923 ** ^A successful call to sqlite3_backup_init() returns a pointer to an
5924 ** [sqlite3_backup] object.
5925 ** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
5926 ** sqlite3_backup_finish() functions to perform the specified backup
5927 ** operation.
5928 **
5929 ** <b>sqlite3_backup_step()</b>
5930 **
5931 ** ^Function sqlite3_backup_step(B,N) will copy up to N pages between
5932 ** the source and destination databases specified by [sqlite3_backup] object B.
5933 ** ^If N is negative, all remaining source pages are copied.
5934 ** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
5935 ** are still more pages to be copied, then the function returns [SQLITE_OK].
5936 ** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
5937 ** from source to destination, then it returns [SQLITE_DONE].
5938 ** ^If an error occurs while running sqlite3_backup_step(B,N),
5939 ** then an [error code] is returned. ^As well as [SQLITE_OK] and
5940 ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
5941 ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
5942 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
5943 **
5944 ** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
5945 ** <ol>
5946 ** <li> the destination database was opened read-only, or
5947 ** <li> the destination database is using write-ahead-log journaling
5948 ** and the destination and source page sizes differ, or
5949 ** <li> the destination database is an in-memory database and the
5950 ** destination and source page sizes differ.
5951 ** </ol>)^
5952 **
5953 ** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
5954 ** the [sqlite3_busy_handler | busy-handler function]
5955 ** is invoked (if one is specified). ^If the
5956 ** busy-handler returns non-zero before the lock is available, then
5957 ** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
5958 ** sqlite3_backup_step() can be retried later. ^If the source
5959 ** [database connection]
5960 ** is being used to write to the source database when sqlite3_backup_step()
5961 ** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
5962 ** case the call to sqlite3_backup_step() can be retried later on. ^(If
5963 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
5964 ** [SQLITE_READONLY] is returned, then
5965 ** there is no point in retrying the call to sqlite3_backup_step(). These
5966 ** errors are considered fatal.)^ The application must accept
5967 ** that the backup operation has failed and pass the backup operation handle
5968 ** to the sqlite3_backup_finish() to release associated resources.
5969 **
5970 ** ^The first call to sqlite3_backup_step() obtains an exclusive lock
5971 ** on the destination file. ^The exclusive lock is not released until either
5972 ** sqlite3_backup_finish() is called or the backup operation is complete
5973 ** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to
5974 ** sqlite3_backup_step() obtains a [shared lock] on the source database that
5975 ** lasts for the duration of the sqlite3_backup_step() call.
5976 ** ^Because the source database is not locked between calls to
5977 ** sqlite3_backup_step(), the source database may be modified mid-way
5978 ** through the backup process. ^If the source database is modified by an
5979 ** external process or via a database connection other than the one being
5980 ** used by the backup operation, then the backup will be automatically
5981 ** restarted by the next call to sqlite3_backup_step(). ^If the source
5982 ** database is modified by the using the same database connection as is used
5983 ** by the backup operation, then the backup database is automatically
5984 ** updated at the same time.
5985 **
5986 ** <b>sqlite3_backup_finish()</b>
5987 **
5988 ** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the
5989 ** application wishes to abandon the backup operation, the application
5990 ** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
5991 ** ^The sqlite3_backup_finish() interfaces releases all
5992 ** resources associated with the [sqlite3_backup] object.
5993 ** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
5994 ** active write-transaction on the destination database is rolled back.
5995 ** The [sqlite3_backup] object is invalid
5996 ** and may not be used following a call to sqlite3_backup_finish().
5997 **
5998 ** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
5999 ** sqlite3_backup_step() errors occurred, regardless or whether or not
6000 ** sqlite3_backup_step() completed.
6001 ** ^If an out-of-memory condition or IO error occurred during any prior
6002 ** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
6003 ** sqlite3_backup_finish() returns the corresponding [error code].
6004 **
6005 ** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
6006 ** is not a permanent error and does not affect the return value of
6007 ** sqlite3_backup_finish().
6008 **
6009 ** <b>sqlite3_backup_remaining(), sqlite3_backup_pagecount()</b>
6010 **
6011 ** ^Each call to sqlite3_backup_step() sets two values inside
6012 ** the [sqlite3_backup] object: the number of pages still to be backed
6013 ** up and the total number of pages in the source database file.
6014 ** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces
6015 ** retrieve these two values, respectively.
6016 **
6017 ** ^The values returned by these functions are only updated by
6018 ** sqlite3_backup_step(). ^If the source database is modified during a backup
6019 ** operation, then the values are not updated to account for any extra
6020 ** pages that need to be updated or the size of the source database file
6021 ** changing.
6022 **
6023 ** <b>Concurrent Usage of Database Handles</b>
6024 **
6025 ** ^The source [database connection] may be used by the application for other
6026 ** purposes while a backup operation is underway or being initialized.
6027 ** ^If SQLite is compiled and configured to support threadsafe database
6028 ** connections, then the source database connection may be used concurrently
6029 ** from within other threads.
6030 **
6031 ** However, the application must guarantee that the destination
6032 ** [database connection] is not passed to any other API (by any thread) after
6033 ** sqlite3_backup_init() is called and before the corresponding call to
6034 ** sqlite3_backup_finish(). SQLite does not currently check to see
6035 ** if the application incorrectly accesses the destination [database connection]
6036 ** and so no error code is reported, but the operations may malfunction
6037 ** nevertheless. Use of the destination database connection while a
6038 ** backup is in progress might also also cause a mutex deadlock.
6039 **
6040 ** If running in [shared cache mode], the application must
6041 ** guarantee that the shared cache used by the destination database
6042 ** is not accessed while the backup is running. In practice this means
6043 ** that the application must guarantee that the disk file being
6044 ** backed up to is not accessed by any connection within the process,
6045 ** not just the specific connection that was passed to sqlite3_backup_init().
6046 **
6047 ** The [sqlite3_backup] object itself is partially threadsafe. Multiple
6048 ** threads may safely make multiple concurrent calls to sqlite3_backup_step().
6049 ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
6050 ** APIs are not strictly speaking threadsafe. If they are invoked at the
6051 ** same time as another thread is invoking sqlite3_backup_step() it is
6052 ** possible that they return invalid values.
6053 */
6059 );
6065 /*
6066 ** CAPI3REF: Unlock Notification
6067 **
6068 ** ^When running in shared-cache mode, a database operation may fail with
6069 ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
6070 ** individual tables within the shared-cache cannot be obtained. See
6071 ** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
6072 ** ^This API may be used to register a callback that SQLite will invoke
6073 ** when the connection currently holding the required lock relinquishes it.
6074 ** ^This API is only available if the library was compiled with the
6075 ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
6076 **
6077 ** See Also: [Using the SQLite Unlock Notification Feature].
6078 **
6079 ** ^Shared-cache locks are released when a database connection concludes
6080 ** its current transaction, either by committing it or rolling it back.
6081 **
6082 ** ^When a connection (known as the blocked connection) fails to obtain a
6083 ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
6084 ** identity of the database connection (the blocking connection) that
6085 ** has locked the required resource is stored internally. ^After an
6086 ** application receives an SQLITE_LOCKED error, it may call the
6087 ** sqlite3_unlock_notify() method with the blocked connection handle as
6088 ** the first argument to register for a callback that will be invoked
6089 ** when the blocking connections current transaction is concluded. ^The
6090 ** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
6091 ** call that concludes the blocking connections transaction.
6092 **
6093 ** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
6094 ** there is a chance that the blocking connection will have already
6095 ** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
6096 ** If this happens, then the specified callback is invoked immediately,
6097 ** from within the call to sqlite3_unlock_notify().)^
6098 **
6099 ** ^If the blocked connection is attempting to obtain a write-lock on a
6100 ** shared-cache table, and more than one other connection currently holds
6101 ** a read-lock on the same table, then SQLite arbitrarily selects one of
6102 ** the other connections to use as the blocking connection.
6103 **
6104 ** ^(There may be at most one unlock-notify callback registered by a
6105 ** blocked connection. If sqlite3_unlock_notify() is called when the
6106 ** blocked connection already has a registered unlock-notify callback,
6107 ** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
6108 ** called with a NULL pointer as its second argument, then any existing
6109 ** unlock-notify callback is canceled. ^The blocked connections
6110 ** unlock-notify callback may also be canceled by closing the blocked
6111 ** connection using [sqlite3_close()].
6112 **
6113 ** The unlock-notify callback is not reentrant. If an application invokes
6114 ** any sqlite3_xxx API functions from within an unlock-notify callback, a
6115 ** crash or deadlock may be the result.
6116 **
6117 ** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
6118 ** returns SQLITE_OK.
6119 **
6120 ** <b>Callback Invocation Details</b>
6121 **
6122 ** When an unlock-notify callback is registered, the application provides a
6123 ** single void* pointer that is passed to the callback when it is invoked.
6124 ** However, the signature of the callback function allows SQLite to pass
6125 ** it an array of void* context pointers. The first argument passed to
6126 ** an unlock-notify callback is a pointer to an array of void* pointers,
6127 ** and the second is the number of entries in the array.
6128 **
6129 ** When a blocking connections transaction is concluded, there may be
6130 ** more than one blocked connection that has registered for an unlock-notify
6131 ** callback. ^If two or more such blocked connections have specified the
6132 ** same callback function, then instead of invoking the callback function
6133 ** multiple times, it is invoked once with the set of void* context pointers
6134 ** specified by the blocked connections bundled together into an array.
6135 ** This gives the application an opportunity to prioritize any actions
6136 ** related to the set of unblocked database connections.
6137 **
6138 ** <b>Deadlock Detection</b>
6139 **
6140 ** Assuming that after registering for an unlock-notify callback a
6141 ** database waits for the callback to be issued before taking any further
6142 ** action (a reasonable assumption), then using this API may cause the
6143 ** application to deadlock. For example, if connection X is waiting for
6144 ** connection Y's transaction to be concluded, and similarly connection
6145 ** Y is waiting on connection X's transaction, then neither connection
6146 ** will proceed and the system may remain deadlocked indefinitely.
6147 **
6148 ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
6149 ** detection. ^If a given call to sqlite3_unlock_notify() would put the
6150 ** system in a deadlocked state, then SQLITE_LOCKED is returned and no
6151 ** unlock-notify callback is registered. The system is said to be in
6152 ** a deadlocked state if connection A has registered for an unlock-notify
6153 ** callback on the conclusion of connection B's transaction, and connection
6154 ** B has itself registered for an unlock-notify callback when connection
6155 ** A's transaction is concluded. ^Indirect deadlock is also detected, so
6156 ** the system is also considered to be deadlocked if connection B has
6157 ** registered for an unlock-notify callback on the conclusion of connection
6158 ** C's transaction, where connection C is waiting on connection A. ^Any
6159 ** number of levels of indirection are allowed.
6160 **
6161 ** <b>The "DROP TABLE" Exception</b>
6162 **
6163 ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost
6164 ** always appropriate to call sqlite3_unlock_notify(). There is however,
6165 ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
6166 ** SQLite checks if there are any currently executing SELECT statements
6167 ** that belong to the same connection. If there are, SQLITE_LOCKED is
6168 ** returned. In this case there is no "blocking connection", so invoking
6169 ** sqlite3_unlock_notify() results in the unlock-notify callback being
6170 ** invoked immediately. If the application then re-attempts the "DROP TABLE"
6171 ** or "DROP INDEX" query, an infinite loop might be the result.
6172 **
6173 ** One way around this problem is to check the extended error code returned
6174 ** by an sqlite3_step() call. ^(If there is a blocking connection, then the
6175 ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
6176 ** the special "DROP TABLE/INDEX" case, the extended error code is just
6177 ** SQLITE_LOCKED.)^
6178 */
6183 );
6186 /*
6187 ** CAPI3REF: String Comparison
6188 **
6189 ** ^The [sqlite3_strnicmp()] API allows applications and extensions to
6190 ** compare the contents of two buffers containing UTF-8 strings in a
6191 ** case-independent fashion, using the same definition of case independence
6192 ** that SQLite uses internally when comparing identifiers.
6193 */
6196 /*
6197 ** CAPI3REF: Error Logging Interface
6198 **
6199 ** ^The [sqlite3_log()] interface writes a message into the error log
6200 ** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
6201 ** ^If logging is enabled, the zFormat string and subsequent arguments are
6202 ** used with [sqlite3_snprintf()] to generate the final output string.
6203 **
6204 ** The sqlite3_log() interface is intended for use by extensions such as
6205 ** virtual tables, collating functions, and SQL functions. While there is
6206 ** nothing to prevent an application from calling sqlite3_log(), doing so
6207 ** is considered bad form.
6208 **
6209 ** The zFormat string must not be NULL.
6210 **
6211 ** To avoid deadlocks and other threading problems, the sqlite3_log() routine
6212 ** will not use dynamically allocated memory. The log message is stored in
6213 ** a fixed-length buffer on the stack. If the log message is longer than
6214 ** a few hundred characters, it will be truncated to the length of the
6215 ** buffer.
6216 */
6219 /*
6220 ** CAPI3REF: Write-Ahead Log Commit Hook
6221 **
6222 ** ^The [sqlite3_wal_hook()] function is used to register a callback that
6223 ** will be invoked each time a database connection commits data to a
6224 ** [write-ahead log] (i.e. whenever a transaction is committed in
6225 ** [journal_mode | journal_mode=WAL mode]).
6226 **
6227 ** ^The callback is invoked by SQLite after the commit has taken place and
6228 ** the associated write-lock on the database released, so the implementation
6229 ** may read, write or [checkpoint] the database as required.
6230 **
6231 ** ^The first parameter passed to the callback function when it is invoked
6232 ** is a copy of the third parameter passed to sqlite3_wal_hook() when
6233 ** registering the callback. ^The second is a copy of the database handle.
6234 ** ^The third parameter is the name of the database that was written to -
6235 ** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
6236 ** is the number of pages currently in the write-ahead log file,
6237 ** including those that were just committed.
6238 **
6239 ** The callback function should normally return [SQLITE_OK]. ^If an error
6240 ** code is returned, that error will propagate back up through the
6241 ** SQLite code base to cause the statement that provoked the callback
6242 ** to report an error, though the commit will have still occurred. If the
6243 ** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
6244 ** that does not correspond to any valid SQLite error code, the results
6245 ** are undefined.
6246 **
6247 ** A single database handle may have at most a single write-ahead log callback
6248 ** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
6249 ** previously registered write-ahead log callback. ^Note that the
6250 ** [sqlite3_wal_autocheckpoint()] interface and the
6251 ** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
6252 ** those overwrite any prior [sqlite3_wal_hook()] settings.
6253 */
6255 sqlite3*,
6258 );
6260 /*
6261 ** CAPI3REF: Configure an auto-checkpoint
6262 **
6263 ** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
6264 ** [sqlite3_wal_hook()] that causes any database on [database connection] D
6265 ** to automatically [checkpoint]
6266 ** after committing a transaction if there are N or
6267 ** more frames in the [write-ahead log] file. ^Passing zero or
6268 ** a negative value as the nFrame parameter disables automatic
6269 ** checkpoints entirely.
6270 **
6271 ** ^The callback registered by this function replaces any existing callback
6272 ** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback
6273 ** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
6274 ** configured by this function.
6275 **
6276 ** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
6277 ** from SQL.
6278 **
6279 ** ^Every new [database connection] defaults to having the auto-checkpoint
6280 ** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
6281 ** pages. The use of this interface
6282 ** is only necessary if the default setting is found to be suboptimal
6283 ** for a particular application.
6284 */
6287 /*
6288 ** CAPI3REF: Checkpoint a database
6289 **
6290 ** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X
6291 ** on [database connection] D to be [checkpointed]. ^If X is NULL or an
6292 ** empty string, then a checkpoint is run on all databases of
6293 ** connection D. ^If the database connection D is not in
6294 ** [WAL | write-ahead log mode] then this interface is a harmless no-op.
6295 **
6296 ** ^The [wal_checkpoint pragma] can be used to invoke this interface
6297 ** from SQL. ^The [sqlite3_wal_autocheckpoint()] interface and the
6298 ** [wal_autocheckpoint pragma] can be used to cause this interface to be
6299 ** run whenever the WAL reaches a certain size threshold.
6300 **
6301 ** See also: [sqlite3_wal_checkpoint_v2()]
6302 */
6305 /*
6306 ** CAPI3REF: Checkpoint a database
6307 **
6308 ** Run a checkpoint operation on WAL database zDb attached to database
6309 ** handle db. The specific operation is determined by the value of the
6310 ** eMode parameter:
6311 **
6312 ** <dl>
6313 ** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
6314 ** Checkpoint as many frames as possible without waiting for any database
6315 ** readers or writers to finish. Sync the db file if all frames in the log
6316 ** are checkpointed. This mode is the same as calling
6317 ** sqlite3_wal_checkpoint(). The busy-handler callback is never invoked.
6318 **
6319 ** <dt>SQLITE_CHECKPOINT_FULL<dd>
6320 ** This mode blocks (calls the busy-handler callback) until there is no
6321 ** database writer and all readers are reading from the most recent database
6322 ** snapshot. It then checkpoints all frames in the log file and syncs the
6323 ** database file. This call blocks database writers while it is running,
6324 ** but not database readers.
6325 **
6326 ** <dt>SQLITE_CHECKPOINT_RESTART<dd>
6327 ** This mode works the same way as SQLITE_CHECKPOINT_FULL, except after
6328 ** checkpointing the log file it blocks (calls the busy-handler callback)
6329 ** until all readers are reading from the database file only. This ensures
6330 ** that the next client to write to the database file restarts the log file
6331 ** from the beginning. This call blocks database writers while it is running,
6332 ** but not database readers.
6333 ** </dl>
6334 **
6335 ** If pnLog is not NULL, then *pnLog is set to the total number of frames in
6336 ** the log file before returning. If pnCkpt is not NULL, then *pnCkpt is set to
6337 ** the total number of checkpointed frames (including any that were already
6338 ** checkpointed when this function is called). *pnLog and *pnCkpt may be
6339 ** populated even if sqlite3_wal_checkpoint_v2() returns other than SQLITE_OK.
6340 ** If no values are available because of an error, they are both set to -1
6341 ** before returning to communicate this to the caller.
6342 **
6343 ** All calls obtain an exclusive "checkpoint" lock on the database file. If
6344 ** any other process is running a checkpoint operation at the same time, the
6345 ** lock cannot be obtained and SQLITE_BUSY is returned. Even if there is a
6346 ** busy-handler configured, it will not be invoked in this case.
6347 **
6348 ** The SQLITE_CHECKPOINT_FULL and RESTART modes also obtain the exclusive
6349 ** "writer" lock on the database file. If the writer lock cannot be obtained
6350 ** immediately, and a busy-handler is configured, it is invoked and the writer
6351 ** lock retried until either the busy-handler returns 0 or the lock is
6352 ** successfully obtained. The busy-handler is also invoked while waiting for
6353 ** database readers as described above. If the busy-handler returns 0 before
6354 ** the writer lock is obtained or while waiting for database readers, the
6355 ** checkpoint operation proceeds from that point in the same way as
6356 ** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible
6357 ** without blocking any further. SQLITE_BUSY is returned in this case.
6358 **
6359 ** If parameter zDb is NULL or points to a zero length string, then the
6360 ** specified operation is attempted on all WAL databases. In this case the
6361 ** values written to output parameters *pnLog and *pnCkpt are undefined. If
6362 ** an SQLITE_BUSY error is encountered when processing one or more of the
6363 ** attached WAL databases, the operation is still attempted on any remaining
6364 ** attached databases and SQLITE_BUSY is returned to the caller. If any other
6365 ** error occurs while processing an attached database, processing is abandoned
6366 ** and the error code returned to the caller immediately. If no error
6367 ** (SQLITE_BUSY or otherwise) is encountered while processing the attached
6368 ** databases, SQLITE_OK is returned.
6369 **
6370 ** If database zDb is the name of an attached database that is not in WAL
6371 ** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. If
6372 ** zDb is not NULL (or a zero length string) and is not the name of any
6373 ** attached database, SQLITE_ERROR is returned to the caller.
6374 */
6381 );
6383 /*
6384 ** CAPI3REF: Checkpoint operation parameters
6385 **
6386 ** These constants can be used as the 3rd parameter to
6387 ** [sqlite3_wal_checkpoint_v2()]. See the [sqlite3_wal_checkpoint_v2()]
6388 ** documentation for additional information about the meaning and use of
6389 ** each of these values.
6390 */
6391 #define SQLITE_CHECKPOINT_PASSIVE 0
6392 #define SQLITE_CHECKPOINT_FULL 1
6393 #define SQLITE_CHECKPOINT_RESTART 2
6396 /* Begin recover.patch for Chromium */
6397 /*
6398 ** Call to initialize the recover virtual-table modules (see recover.c).
6399 **
6400 ** This could be loaded by default in main.c, but that would make the
6401 ** virtual table available to Web SQL. Breaking it out allows only
6402 ** selected users to enable it (currently sql/recovery.cc).
6403 */
6405 /* End recover.patch for Chromium */
6407 /*
6408 ** Undo the hack that converts floating point types to integer for
6409 ** builds on processors without floating point support.
6410 */
6411 #ifdef SQLITE_OMIT_FLOATING_POINT
6412 # undef double
6413 #endif
6415 #ifdef __cplusplus
6417 #endif
6418 #endif
6420 /*
6421 ** 2010 August 30
6422 **
6423 ** The author disclaims copyright to this source code. In place of
6424 ** a legal notice, here is a blessing:
6425 **
6426 ** May you do good and not evil.
6427 ** May you find forgiveness for yourself and forgive others.
6428 ** May you share freely, never taking more than you give.
6429 **
6430 *************************************************************************
6431 */
6433 #ifndef _SQLITE3RTREE_H_
6434 #define _SQLITE3RTREE_H_
6437 #ifdef __cplusplus
6439 #endif
6443 /*
6444 ** Register a geometry callback named zGeom that can be used as part of an
6445 ** R-Tree geometry query as follows:
6446 **
6447 ** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...)
6448 */
6454 );
6457 /*
6458 ** A pointer to a structure of the following type is passed as the first
6459 ** argument to callbacks registered using rtree_geometry_callback().
6460 */
6467 };
6470 #ifdef __cplusplus
6472 #endif