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1 /*
2 ** 2001 September 15
3 **
4 ** The author disclaims copyright to this source code. In place of
5 ** a legal notice, here is a blessing:
6 **
7 ** May you do good and not evil.
8 ** May you find forgiveness for yourself and forgive others.
9 ** May you share freely, never taking more than you give.
10 **
11 *************************************************************************
12 ** This header file defines the interface that the SQLite library
13 ** presents to client programs. If a C-function, structure, datatype,
14 ** or constant definition does not appear in this file, then it is
15 ** not a published API of SQLite, is subject to change without
16 ** notice, and should not be referenced by programs that use SQLite.
17 **
18 ** Some of the definitions that are in this file are marked as
19 ** "experimental". Experimental interfaces are normally new
20 ** features recently added to SQLite. We do not anticipate changes
21 ** to experimental interfaces but reserve the right to make minor changes
22 ** if experience from use "in the wild" suggest such changes are prudent.
23 **
24 ** The official C-language API documentation for SQLite is derived
25 ** from comments in this file. This file is the authoritative source
26 ** on how SQLite interfaces are suppose to operate.
27 **
28 ** The name of this file under configuration management is "sqlite.h.in".
29 ** The makefile makes some minor changes to this file (such as inserting
30 ** the version number) and changes its name to "sqlite3.h" as
31 ** part of the build process.
32 */
33 #ifndef _SQLITE3_H_
34 #define _SQLITE3_H_
35 #include <stdarg.h> /* Needed for the definition of va_list */
36
37 /*
38 ** Make sure we can call this stuff from C++.
39 */
40 #ifdef __cplusplus
41 extern "C" {
42 #endif
43
44
45 /*
46 ** Add the ability to override 'extern'
47 */
48 #ifndef SQLITE_EXTERN
49 # define SQLITE_EXTERN extern
50 #endif
51
52 #ifndef SQLITE_API
53 # define SQLITE_API
54 #endif
55
56
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
72
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
82
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 */
110 #define SQLITE_VERSION "3.7.16"
111 #define SQLITE_VERSION_NUMBER 3007016
112 #define SQLITE_SOURCE_ID "2013-03-18 11:39:23 66d5f2b76750f3520eb7a495f6247206758f5b90"
113
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 */
144 SQLITE_API SQLITE_EXTERN const char sqlite3_version[];
145 SQLITE_API const char *sqlite3_libversion(void);
146 SQLITE_API const char *sqlite3_sourceid(void);
147 SQLITE_API int sqlite3_libversion_number(void);
148
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
172 SQLITE_API int sqlite3_compileoption_used(const char *zOptName);
173 SQLITE_API const char *sqlite3_compileoption_get(int N);
174 #endif
175
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 with 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 */
212 SQLITE_API int sqlite3_threadsafe(void);
213
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 ** and [sqlite3_close_v2()] are its destructors. There are many other
223 ** interfaces (such as
224 ** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
225 ** [sqlite3_busy_timeout()] to name but three) that are methods on an
226 ** sqlite3 object.
227 */
228 typedef struct sqlite3 sqlite3;
229
230 /*
231 ** CAPI3REF: 64-Bit Integer Types
232 ** KEYWORDS: sqlite_int64 sqlite_uint64
233 **
234 ** Because there is no cross-platform way to specify 64-bit integer types
235 ** SQLite includes typedefs for 64-bit signed and unsigned integers.
236 **
237 ** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
238 ** The sqlite_int64 and sqlite_uint64 types are supported for backwards
239 ** compatibility only.
240 **
241 ** ^The sqlite3_int64 and sqlite_int64 types can store integer values
242 ** between -9223372036854775808 and +9223372036854775807 inclusive. ^The
243 ** sqlite3_uint64 and sqlite_uint64 types can store integer values
244 ** between 0 and +18446744073709551615 inclusive.
245 */
246 #ifdef SQLITE_INT64_TYPE
247 typedef SQLITE_INT64_TYPE sqlite_int64;
248 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
249 #elif defined(_MSC_VER) || defined(__BORLANDC__)
250 typedef __int64 sqlite_int64;
251 typedef unsigned __int64 sqlite_uint64;
252 #else
253 typedef long long int sqlite_int64;
254 typedef unsigned long long int sqlite_uint64;
255 #endif
256 typedef sqlite_int64 sqlite3_int64;
257 typedef sqlite_uint64 sqlite3_uint64;
258
259 /*
260 ** If compiling for a processor that lacks floating point support,
261 ** substitute integer for floating-point.
262 */
263 #ifdef SQLITE_OMIT_FLOATING_POINT
264 # define double sqlite3_int64
265 #endif
266
267 /*
268 ** CAPI3REF: Closing A Database Connection
269 **
270 ** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors
271 ** for the [sqlite3] object.
272 ** ^Calls to sqlite3_close() and sqlite3_close_v2() return SQLITE_OK if
273 ** the [sqlite3] object is successfully destroyed and all associated
274 ** resources are deallocated.
275 **
276 ** ^If the database connection is associated with unfinalized prepared
277 ** statements or unfinished sqlite3_backup objects then sqlite3_close()
278 ** will leave the database connection open and return [SQLITE_BUSY].
279 ** ^If sqlite3_close_v2() is called with unfinalized prepared statements
280 ** and unfinished sqlite3_backups, then the database connection becomes
281 ** an unusable "zombie" which will automatically be deallocated when the
282 ** last prepared statement is finalized or the last sqlite3_backup is
283 ** finished. The sqlite3_close_v2() interface is intended for use with
284 ** host languages that are garbage collected, and where the order in which
285 ** destructors are called is arbitrary.
286 **
287 ** Applications should [sqlite3_finalize | finalize] all [prepared statements],
288 ** [sqlite3_blob_close | close] all [BLOB handles], and
289 ** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated
290 ** with the [sqlite3] object prior to attempting to close the object. ^If
291 ** sqlite3_close_v2() is called on a [database connection] that still has
292 ** outstanding [prepared statements], [BLOB handles], and/or
293 ** [sqlite3_backup] objects then it returns SQLITE_OK but the deallocation
294 ** of resources is deferred until all [prepared statements], [BLOB handles],
295 ** and [sqlite3_backup] objects are also destroyed.
296 **
297 ** ^If an [sqlite3] object is destroyed while a transaction is open,
298 ** the transaction is automatically rolled back.
299 **
300 ** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)]
301 ** must be either a NULL
302 ** pointer or an [sqlite3] object pointer obtained
303 ** from [sqlite3_open()], [sqlite3_open16()], or
304 ** [sqlite3_open_v2()], and not previously closed.
305 ** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer
306 ** argument is a harmless no-op.
307 */
308 SQLITE_API int sqlite3_close(sqlite3*);
309 SQLITE_API int sqlite3_close_v2(sqlite3*);
310
311 /*
312 ** The type for a callback function.
313 ** This is legacy and deprecated. It is included for historical
314 ** compatibility and is not documented.
315 */
316 typedef int (*sqlite3_callback)(void*,int,char**, char**);
317
318 /*
319 ** CAPI3REF: One-Step Query Execution Interface
320 **
321 ** The sqlite3_exec() interface is a convenience wrapper around
322 ** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
323 ** that allows an application to run multiple statements of SQL
324 ** without having to use a lot of C code.
325 **
326 ** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
327 ** semicolon-separate SQL statements passed into its 2nd argument,
328 ** in the context of the [database connection] passed in as its 1st
329 ** argument. ^If the callback function of the 3rd argument to
330 ** sqlite3_exec() is not NULL, then it is invoked for each result row
331 ** coming out of the evaluated SQL statements. ^The 4th argument to
332 ** sqlite3_exec() is relayed through to the 1st argument of each
333 ** callback invocation. ^If the callback pointer to sqlite3_exec()
334 ** is NULL, then no callback is ever invoked and result rows are
335 ** ignored.
336 **
337 ** ^If an error occurs while evaluating the SQL statements passed into
338 ** sqlite3_exec(), then execution of the current statement stops and
339 ** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec()
340 ** is not NULL then any error message is written into memory obtained
341 ** from [sqlite3_malloc()] and passed back through the 5th parameter.
342 ** To avoid memory leaks, the application should invoke [sqlite3_free()]
343 ** on error message strings returned through the 5th parameter of
344 ** of sqlite3_exec() after the error message string is no longer needed.
345 ** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
346 ** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
347 ** NULL before returning.
348 **
349 ** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
350 ** routine returns SQLITE_ABORT without invoking the callback again and
351 ** without running any subsequent SQL statements.
352 **
353 ** ^The 2nd argument to the sqlite3_exec() callback function is the
354 ** number of columns in the result. ^The 3rd argument to the sqlite3_exec()
355 ** callback is an array of pointers to strings obtained as if from
356 ** [sqlite3_column_text()], one for each column. ^If an element of a
357 ** result row is NULL then the corresponding string pointer for the
358 ** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the
359 ** sqlite3_exec() callback is an array of pointers to strings where each
360 ** entry represents the name of corresponding result column as obtained
361 ** from [sqlite3_column_name()].
362 **
363 ** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
364 ** to an empty string, or a pointer that contains only whitespace and/or
365 ** SQL comments, then no SQL statements are evaluated and the database
366 ** is not changed.
367 **
368 ** Restrictions:
369 **
370 ** <ul>
371 ** <li> The application must insure that the 1st parameter to sqlite3_exec()
372 ** is a valid and open [database connection].
373 ** <li> The application must not close [database connection] specified by
374 ** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
375 ** <li> The application must not modify the SQL statement text passed into
376 ** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
377 ** </ul>
378 */
379 SQLITE_API int sqlite3_exec(
380 sqlite3*, /* An open database */
381 const char *sql, /* SQL to be evaluated */
382 int (*callback)(void*,int,char**,char**), /* Callback function */
383 void *, /* 1st argument to callback */
384 char **errmsg /* Error msg written here */
385 );
386
387 /*
388 ** CAPI3REF: Result Codes
389 ** KEYWORDS: SQLITE_OK {error code} {error codes}
390 ** KEYWORDS: {result code} {result codes}
391 **
392 ** Many SQLite functions return an integer result code from the set shown
393 ** here in order to indicate success or failure.
394 **
395 ** New error codes may be added in future versions of SQLite.
396 **
397 ** See also: [SQLITE_IOERR_READ | extended result codes],
398 ** [sqlite3_vtab_on_conflict()] [SQLITE_ROLLBACK | result codes].
399 */
400 #define SQLITE_OK 0 /* Successful result */
401 /* beginning-of-error-codes */
402 #define SQLITE_ERROR 1 /* SQL error or missing database */
403 #define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */
404 #define SQLITE_PERM 3 /* Access permission denied */
405 #define SQLITE_ABORT 4 /* Callback routine requested an abort */
406 #define SQLITE_BUSY 5 /* The database file is locked */
407 #define SQLITE_LOCKED 6 /* A table in the database is locked */
408 #define SQLITE_NOMEM 7 /* A malloc() failed */
409 #define SQLITE_READONLY 8 /* Attempt to write a readonly database */
410 #define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/
411 #define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */
412 #define SQLITE_CORRUPT 11 /* The database disk image is malformed */
413 #define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */
414 #define SQLITE_FULL 13 /* Insertion failed because database is full */
415 #define SQLITE_CANTOPEN 14 /* Unable to open the database file */
416 #define SQLITE_PROTOCOL 15 /* Database lock protocol error */
417 #define SQLITE_EMPTY 16 /* Database is empty */
418 #define SQLITE_SCHEMA 17 /* The database schema changed */
419 #define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */
420 #define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */
421 #define SQLITE_MISMATCH 20 /* Data type mismatch */
422 #define SQLITE_MISUSE 21 /* Library used incorrectly */
423 #define SQLITE_NOLFS 22 /* Uses OS features not supported on host */
424 #define SQLITE_AUTH 23 /* Authorization denied */
425 #define SQLITE_FORMAT 24 /* Auxiliary database format error */
426 #define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */
427 #define SQLITE_NOTADB 26 /* File opened that is not a database file */
428 #define SQLITE_ROW 100 /* sqlite3_step() has another row ready */
429 #define SQLITE_DONE 101 /* sqlite3_step() has finished executing */
430 /* end-of-error-codes */
431
432 /*
433 ** CAPI3REF: Extended Result Codes
434 ** KEYWORDS: {extended error code} {extended error codes}
435 ** KEYWORDS: {extended result code} {extended result codes}
436 **
437 ** In its default configuration, SQLite API routines return one of 26 integer
438 ** [SQLITE_OK | result codes]. However, experience has shown that many of
439 ** these result codes are too coarse-grained. They do not provide as
440 ** much information about problems as programmers might like. In an effort to
441 ** address this, newer versions of SQLite (version 3.3.8 and later) include
442 ** support for additional result codes that provide more detailed information
443 ** about errors. The extended result codes are enabled or disabled
444 ** on a per database connection basis using the
445 ** [sqlite3_extended_result_codes()] API.
446 **
447 ** Some of the available extended result codes are listed here.
448 ** One may expect the number of extended result codes will be expand
449 ** over time. Software that uses extended result codes should expect
450 ** to see new result codes in future releases of SQLite.
451 **
452 ** The SQLITE_OK result code will never be extended. It will always
453 ** be exactly zero.
454 */
455 #define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8))
456 #define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8))
457 #define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8))
458 #define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8))
459 #define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8))
460 #define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8))
461 #define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8))
462 #define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8))
463 #define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8))
464 #define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8))
465 #define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8))
466 #define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8))
467 #define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8))
468 #define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
469 #define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8))
470 #define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8))
471 #define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8))
472 #define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8))
473 #define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8))
474 #define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8))
475 #define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8))
476 #define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8))
477 #define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8))
478 #define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8))
479 #define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8))
480 #define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8))
481 #define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8))
482 #define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8))
483 #define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8))
484 #define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8))
485 #define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8))
486 #define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8))
487 #define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8))
488 #define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8))
489 #define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8))
490 #define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8))
491 #define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8))
492 #define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8))
493 #define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8))
494 #define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8))
495 #define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8))
496 #define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8))
497
498 /*
499 ** CAPI3REF: Flags For File Open Operations
500 **
501 ** These bit values are intended for use in the
502 ** 3rd parameter to the [sqlite3_open_v2()] interface and
503 ** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
504 */
505 #define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */
506 #define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */
507 #define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */
508 #define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */
509 #define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */
510 #define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */
511 #define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */
512 #define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */
513 #define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */
514 #define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */
515 #define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */
516 #define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */
517 #define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */
518 #define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */
519 #define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */
520 #define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */
521 #define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */
522 #define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */
523 #define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */
524 #define SQLITE_OPEN_WAL 0x00080000 /* VFS only */
525
526 /* Reserved: 0x00F00000 */
527
528 /*
529 ** CAPI3REF: Device Characteristics
530 **
531 ** The xDeviceCharacteristics method of the [sqlite3_io_methods]
532 ** object returns an integer which is a vector of these
533 ** bit values expressing I/O characteristics of the mass storage
534 ** device that holds the file that the [sqlite3_io_methods]
535 ** refers to.
536 **
537 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
538 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
539 ** mean that writes of blocks that are nnn bytes in size and
540 ** are aligned to an address which is an integer multiple of
541 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
542 ** that when data is appended to a file, the data is appended
543 ** first then the size of the file is extended, never the other
544 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
545 ** information is written to disk in the same order as calls
546 ** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
547 ** after reboot following a crash or power loss, the only bytes in a
548 ** file that were written at the application level might have changed
549 ** and that adjacent bytes, even bytes within the same sector are
550 ** guaranteed to be unchanged.
551 */
552 #define SQLITE_IOCAP_ATOMIC 0x00000001
553 #define SQLITE_IOCAP_ATOMIC512 0x00000002
554 #define SQLITE_IOCAP_ATOMIC1K 0x00000004
555 #define SQLITE_IOCAP_ATOMIC2K 0x00000008
556 #define SQLITE_IOCAP_ATOMIC4K 0x00000010
557 #define SQLITE_IOCAP_ATOMIC8K 0x00000020
558 #define SQLITE_IOCAP_ATOMIC16K 0x00000040
559 #define SQLITE_IOCAP_ATOMIC32K 0x00000080
560 #define SQLITE_IOCAP_ATOMIC64K 0x00000100
561 #define SQLITE_IOCAP_SAFE_APPEND 0x00000200
562 #define SQLITE_IOCAP_SEQUENTIAL 0x00000400
563 #define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800
564 #define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000
565
566 /*
567 ** CAPI3REF: File Locking Levels
568 **
569 ** SQLite uses one of these integer values as the second
570 ** argument to calls it makes to the xLock() and xUnlock() methods
571 ** of an [sqlite3_io_methods] object.
572 */
573 #define SQLITE_LOCK_NONE 0
574 #define SQLITE_LOCK_SHARED 1
575 #define SQLITE_LOCK_RESERVED 2
576 #define SQLITE_LOCK_PENDING 3
577 #define SQLITE_LOCK_EXCLUSIVE 4
578
579 /*
580 ** CAPI3REF: Synchronization Type Flags
581 **
582 ** When SQLite invokes the xSync() method of an
583 ** [sqlite3_io_methods] object it uses a combination of
584 ** these integer values as the second argument.
585 **
586 ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
587 ** sync operation only needs to flush data to mass storage. Inode
588 ** information need not be flushed. If the lower four bits of the flag
589 ** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
590 ** If the lower four bits equal SQLITE_SYNC_FULL, that means
591 ** to use Mac OS X style fullsync instead of fsync().
592 **
593 ** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
594 ** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
595 ** settings. The [synchronous pragma] determines when calls to the
596 ** xSync VFS method occur and applies uniformly across all platforms.
597 ** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
598 ** energetic or rigorous or forceful the sync operations are and
599 ** only make a difference on Mac OSX for the default SQLite code.
600 ** (Third-party VFS implementations might also make the distinction
601 ** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
602 ** operating systems natively supported by SQLite, only Mac OSX
603 ** cares about the difference.)
604 */
605 #define SQLITE_SYNC_NORMAL 0x00002
606 #define SQLITE_SYNC_FULL 0x00003
607 #define SQLITE_SYNC_DATAONLY 0x00010
608
609 /*
610 ** CAPI3REF: OS Interface Open File Handle
611 **
612 ** An [sqlite3_file] object represents an open file in the
613 ** [sqlite3_vfs | OS interface layer]. Individual OS interface
614 ** implementations will
615 ** want to subclass this object by appending additional fields
616 ** for their own use. The pMethods entry is a pointer to an
617 ** [sqlite3_io_methods] object that defines methods for performing
618 ** I/O operations on the open file.
619 */
620 typedef struct sqlite3_file sqlite3_file;
621 struct sqlite3_file {
622 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */
623 };
624
625 /*
626 ** CAPI3REF: OS Interface File Virtual Methods Object
627 **
628 ** Every file opened by the [sqlite3_vfs.xOpen] method populates an
629 ** [sqlite3_file] object (or, more commonly, a subclass of the
630 ** [sqlite3_file] object) with a pointer to an instance of this object.
631 ** This object defines the methods used to perform various operations
632 ** against the open file represented by the [sqlite3_file] object.
633 **
634 ** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element
635 ** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
636 ** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The
637 ** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
638 ** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
639 ** to NULL.
640 **
641 ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
642 ** [SQLITE_SYNC_FULL]. The first choice is the normal fsync().
643 ** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY]
644 ** flag may be ORed in to indicate that only the data of the file
645 ** and not its inode needs to be synced.
646 **
647 ** The integer values to xLock() and xUnlock() are one of
648 ** <ul>
649 ** <li> [SQLITE_LOCK_NONE],
650 ** <li> [SQLITE_LOCK_SHARED],
651 ** <li> [SQLITE_LOCK_RESERVED],
652 ** <li> [SQLITE_LOCK_PENDING], or
653 ** <li> [SQLITE_LOCK_EXCLUSIVE].
654 ** </ul>
655 ** xLock() increases the lock. xUnlock() decreases the lock.
656 ** The xCheckReservedLock() method checks whether any database connection,
657 ** either in this process or in some other process, is holding a RESERVED,
658 ** PENDING, or EXCLUSIVE lock on the file. It returns true
659 ** if such a lock exists and false otherwise.
660 **
661 ** The xFileControl() method is a generic interface that allows custom
662 ** VFS implementations to directly control an open file using the
663 ** [sqlite3_file_control()] interface. The second "op" argument is an
664 ** integer opcode. The third argument is a generic pointer intended to
665 ** point to a structure that may contain arguments or space in which to
666 ** write return values. Potential uses for xFileControl() might be
667 ** functions to enable blocking locks with timeouts, to change the
668 ** locking strategy (for example to use dot-file locks), to inquire
669 ** about the status of a lock, or to break stale locks. The SQLite
670 ** core reserves all opcodes less than 100 for its own use.
671 ** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available.
672 ** Applications that define a custom xFileControl method should use opcodes
673 ** greater than 100 to avoid conflicts. VFS implementations should
674 ** return [SQLITE_NOTFOUND] for file control opcodes that they do not
675 ** recognize.
676 **
677 ** The xSectorSize() method returns the sector size of the
678 ** device that underlies the file. The sector size is the
679 ** minimum write that can be performed without disturbing
680 ** other bytes in the file. The xDeviceCharacteristics()
681 ** method returns a bit vector describing behaviors of the
682 ** underlying device:
683 **
684 ** <ul>
685 ** <li> [SQLITE_IOCAP_ATOMIC]
686 ** <li> [SQLITE_IOCAP_ATOMIC512]
687 ** <li> [SQLITE_IOCAP_ATOMIC1K]
688 ** <li> [SQLITE_IOCAP_ATOMIC2K]
689 ** <li> [SQLITE_IOCAP_ATOMIC4K]
690 ** <li> [SQLITE_IOCAP_ATOMIC8K]
691 ** <li> [SQLITE_IOCAP_ATOMIC16K]
692 ** <li> [SQLITE_IOCAP_ATOMIC32K]
693 ** <li> [SQLITE_IOCAP_ATOMIC64K]
694 ** <li> [SQLITE_IOCAP_SAFE_APPEND]
695 ** <li> [SQLITE_IOCAP_SEQUENTIAL]
696 ** </ul>
697 **
698 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
699 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
700 ** mean that writes of blocks that are nnn bytes in size and
701 ** are aligned to an address which is an integer multiple of
702 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
703 ** that when data is appended to a file, the data is appended
704 ** first then the size of the file is extended, never the other
705 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
706 ** information is written to disk in the same order as calls
707 ** to xWrite().
708 **
709 ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
710 ** in the unread portions of the buffer with zeros. A VFS that
711 ** fails to zero-fill short reads might seem to work. However,
712 ** failure to zero-fill short reads will eventually lead to
713 ** database corruption.
714 */
715 typedef struct sqlite3_io_methods sqlite3_io_methods;
716 struct sqlite3_io_methods {
717 int iVersion;
718 int (*xClose)(sqlite3_file*);
719 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
720 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
721 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
722 int (*xSync)(sqlite3_file*, int flags);
723 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
724 int (*xLock)(sqlite3_file*, int);
725 int (*xUnlock)(sqlite3_file*, int);
726 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
727 int (*xFileControl)(sqlite3_file*, int op, void *pArg);
728 int (*xSectorSize)(sqlite3_file*);
729 int (*xDeviceCharacteristics)(sqlite3_file*);
730 /* Methods above are valid for version 1 */
731 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
732 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
733 void (*xShmBarrier)(sqlite3_file*);
734 int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
735 /* Methods above are valid for version 2 */
736 /* Additional methods may be added in future releases */
737 };
738
739 /*
740 ** CAPI3REF: Standard File Control Opcodes
741 **
742 ** These integer constants are opcodes for the xFileControl method
743 ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
744 ** interface.
745 **
746 ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This
747 ** opcode causes the xFileControl method to write the current state of
748 ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
749 ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
750 ** into an integer that the pArg argument points to. This capability
751 ** is used during testing and only needs to be supported when SQLITE_TEST
752 ** is defined.
753 ** <ul>
754 ** <li>[[SQLITE_FCNTL_SIZE_HINT]]
755 ** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
756 ** layer a hint of how large the database file will grow to be during the
757 ** current transaction. This hint is not guaranteed to be accurate but it
758 ** is often close. The underlying VFS might choose to preallocate database
759 ** file space based on this hint in order to help writes to the database
760 ** file run faster.
761 **
762 ** <li>[[SQLITE_FCNTL_CHUNK_SIZE]]
763 ** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
764 ** extends and truncates the database file in chunks of a size specified
765 ** by the user. The fourth argument to [sqlite3_file_control()] should
766 ** point to an integer (type int) containing the new chunk-size to use
767 ** for the nominated database. Allocating database file space in large
768 ** chunks (say 1MB at a time), may reduce file-system fragmentation and
769 ** improve performance on some systems.
770 **
771 ** <li>[[SQLITE_FCNTL_FILE_POINTER]]
772 ** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
773 ** to the [sqlite3_file] object associated with a particular database
774 ** connection. See the [sqlite3_file_control()] documentation for
775 ** additional information.
776 **
777 ** <li>[[SQLITE_FCNTL_SYNC_OMITTED]]
778 ** ^(The [SQLITE_FCNTL_SYNC_OMITTED] opcode is generated internally by
779 ** SQLite and sent to all VFSes in place of a call to the xSync method
780 ** when the database connection has [PRAGMA synchronous] set to OFF.)^
781 ** Some specialized VFSes need this signal in order to operate correctly
782 ** when [PRAGMA synchronous | PRAGMA synchronous=OFF] is set, but most
783 ** VFSes do not need this signal and should silently ignore this opcode.
784 ** Applications should not call [sqlite3_file_control()] with this
785 ** opcode as doing so may disrupt the operation of the specialized VFSes
786 ** that do require it.
787 **
788 ** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]]
789 ** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
790 ** retry counts and intervals for certain disk I/O operations for the
791 ** windows [VFS] in order to provide robustness in the presence of
792 ** anti-virus programs. By default, the windows VFS will retry file read,
793 ** file write, and file delete operations up to 10 times, with a delay
794 ** of 25 milliseconds before the first retry and with the delay increasing
795 ** by an additional 25 milliseconds with each subsequent retry. This
796 ** opcode allows these two values (10 retries and 25 milliseconds of delay)
797 ** to be adjusted. The values are changed for all database connections
798 ** within the same process. The argument is a pointer to an array of two
799 ** integers where the first integer i the new retry count and the second
800 ** integer is the delay. If either integer is negative, then the setting
801 ** is not changed but instead the prior value of that setting is written
802 ** into the array entry, allowing the current retry settings to be
803 ** interrogated. The zDbName parameter is ignored.
804 **
805 ** <li>[[SQLITE_FCNTL_PERSIST_WAL]]
806 ** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
807 ** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary
808 ** write ahead log and shared memory files used for transaction control
809 ** are automatically deleted when the latest connection to the database
810 ** closes. Setting persistent WAL mode causes those files to persist after
811 ** close. Persisting the files is useful when other processes that do not
812 ** have write permission on the directory containing the database file want
813 ** to read the database file, as the WAL and shared memory files must exist
814 ** in order for the database to be readable. The fourth parameter to
815 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
816 ** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
817 ** WAL mode. If the integer is -1, then it is overwritten with the current
818 ** WAL persistence setting.
819 **
820 ** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]]
821 ** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
822 ** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting
823 ** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
824 ** xDeviceCharacteristics methods. The fourth parameter to
825 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
826 ** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
827 ** mode. If the integer is -1, then it is overwritten with the current
828 ** zero-damage mode setting.
829 **
830 ** <li>[[SQLITE_FCNTL_OVERWRITE]]
831 ** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
832 ** a write transaction to indicate that, unless it is rolled back for some
833 ** reason, the entire database file will be overwritten by the current
834 ** transaction. This is used by VACUUM operations.
835 **
836 ** <li>[[SQLITE_FCNTL_VFSNAME]]
837 ** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
838 ** all [VFSes] in the VFS stack. The names are of all VFS shims and the
839 ** final bottom-level VFS are written into memory obtained from
840 ** [sqlite3_malloc()] and the result is stored in the char* variable
841 ** that the fourth parameter of [sqlite3_file_control()] points to.
842 ** The caller is responsible for freeing the memory when done. As with
843 ** all file-control actions, there is no guarantee that this will actually
844 ** do anything. Callers should initialize the char* variable to a NULL
845 ** pointer in case this file-control is not implemented. This file-control
846 ** is intended for diagnostic use only.
847 **
848 ** <li>[[SQLITE_FCNTL_PRAGMA]]
849 ** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA]
850 ** file control is sent to the open [sqlite3_file] object corresponding
851 ** to the database file to which the pragma statement refers. ^The argument
852 ** to the [SQLITE_FCNTL_PRAGMA] file control is an array of
853 ** pointers to strings (char**) in which the second element of the array
854 ** is the name of the pragma and the third element is the argument to the
855 ** pragma or NULL if the pragma has no argument. ^The handler for an
856 ** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element
857 ** of the char** argument point to a string obtained from [sqlite3_mprintf()]
858 ** or the equivalent and that string will become the result of the pragma or
859 ** the error message if the pragma fails. ^If the
860 ** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal
861 ** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA]
862 ** file control returns [SQLITE_OK], then the parser assumes that the
863 ** VFS has handled the PRAGMA itself and the parser generates a no-op
864 ** prepared statement. ^If the [SQLITE_FCNTL_PRAGMA] file control returns
865 ** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means
866 ** that the VFS encountered an error while handling the [PRAGMA] and the
867 ** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA]
868 ** file control occurs at the beginning of pragma statement analysis and so
869 ** it is able to override built-in [PRAGMA] statements.
870 **
871 ** <li>[[SQLITE_FCNTL_BUSYHANDLER]]
872 ** ^This file-control may be invoked by SQLite on the database file handle
873 ** shortly after it is opened in order to provide a custom VFS with access
874 ** to the connections busy-handler callback. The argument is of type (void **)
875 ** - an array of two (void *) values. The first (void *) actually points
876 ** to a function of type (int (*)(void *)). In order to invoke the connections
877 ** busy-handler, this function should be invoked with the second (void *) in
878 ** the array as the only argument. If it returns non-zero, then the operation
879 ** should be retried. If it returns zero, the custom VFS should abandon the
880 ** current operation.
881 **
882 ** <li>[[SQLITE_FCNTL_TEMPFILENAME]]
883 ** ^Application can invoke this file-control to have SQLite generate a
884 ** temporary filename using the same algorithm that is followed to generate
885 ** temporary filenames for TEMP tables and other internal uses. The
886 ** argument should be a char** which will be filled with the filename
887 ** written into memory obtained from [sqlite3_malloc()]. The caller should
888 ** invoke [sqlite3_free()] on the result to avoid a memory leak.
889 **
890 ** </ul>
891 */
892 #define SQLITE_FCNTL_LOCKSTATE 1
893 #define SQLITE_GET_LOCKPROXYFILE 2
894 #define SQLITE_SET_LOCKPROXYFILE 3
895 #define SQLITE_LAST_ERRNO 4
896 #define SQLITE_FCNTL_SIZE_HINT 5
897 #define SQLITE_FCNTL_CHUNK_SIZE 6
898 #define SQLITE_FCNTL_FILE_POINTER 7
899 #define SQLITE_FCNTL_SYNC_OMITTED 8
900 #define SQLITE_FCNTL_WIN32_AV_RETRY 9
901 #define SQLITE_FCNTL_PERSIST_WAL 10
902 #define SQLITE_FCNTL_OVERWRITE 11
903 #define SQLITE_FCNTL_VFSNAME 12
904 #define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13
905 #define SQLITE_FCNTL_PRAGMA 14
906 #define SQLITE_FCNTL_BUSYHANDLER 15
907 #define SQLITE_FCNTL_TEMPFILENAME 16
908
909 /*
910 ** CAPI3REF: Mutex Handle
911 **
912 ** The mutex module within SQLite defines [sqlite3_mutex] to be an
913 ** abstract type for a mutex object. The SQLite core never looks
914 ** at the internal representation of an [sqlite3_mutex]. It only
915 ** deals with pointers to the [sqlite3_mutex] object.
916 **
917 ** Mutexes are created using [sqlite3_mutex_alloc()].
918 */
919 typedef struct sqlite3_mutex sqlite3_mutex;
920
921 /*
922 ** CAPI3REF: OS Interface Object
923 **
924 ** An instance of the sqlite3_vfs object defines the interface between
925 ** the SQLite core and the underlying operating system. The "vfs"
926 ** in the name of the object stands for "virtual file system". See
927 ** the [VFS | VFS documentation] for further information.
928 **
929 ** The value of the iVersion field is initially 1 but may be larger in
930 ** future versions of SQLite. Additional fields may be appended to this
931 ** object when the iVersion value is increased. Note that the structure
932 ** of the sqlite3_vfs object changes in the transaction between
933 ** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not
934 ** modified.
935 **
936 ** The szOsFile field is the size of the subclassed [sqlite3_file]
937 ** structure used by this VFS. mxPathname is the maximum length of
938 ** a pathname in this VFS.
939 **
940 ** Registered sqlite3_vfs objects are kept on a linked list formed by
941 ** the pNext pointer. The [sqlite3_vfs_register()]
942 ** and [sqlite3_vfs_unregister()] interfaces manage this list
943 ** in a thread-safe way. The [sqlite3_vfs_find()] interface
944 ** searches the list. Neither the application code nor the VFS
945 ** implementation should use the pNext pointer.
946 **
947 ** The pNext field is the only field in the sqlite3_vfs
948 ** structure that SQLite will ever modify. SQLite will only access
949 ** or modify this field while holding a particular static mutex.
950 ** The application should never modify anything within the sqlite3_vfs
951 ** object once the object has been registered.
952 **
953 ** The zName field holds the name of the VFS module. The name must
954 ** be unique across all VFS modules.
955 **
956 ** [[sqlite3_vfs.xOpen]]
957 ** ^SQLite guarantees that the zFilename parameter to xOpen
958 ** is either a NULL pointer or string obtained
959 ** from xFullPathname() with an optional suffix added.
960 ** ^If a suffix is added to the zFilename parameter, it will
961 ** consist of a single "-" character followed by no more than
962 ** 11 alphanumeric and/or "-" characters.
963 ** ^SQLite further guarantees that
964 ** the string will be valid and unchanged until xClose() is
965 ** called. Because of the previous sentence,
966 ** the [sqlite3_file] can safely store a pointer to the
967 ** filename if it needs to remember the filename for some reason.
968 ** If the zFilename parameter to xOpen is a NULL pointer then xOpen
969 ** must invent its own temporary name for the file. ^Whenever the
970 ** xFilename parameter is NULL it will also be the case that the
971 ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
972 **
973 ** The flags argument to xOpen() includes all bits set in
974 ** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()]
975 ** or [sqlite3_open16()] is used, then flags includes at least
976 ** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE].
977 ** If xOpen() opens a file read-only then it sets *pOutFlags to
978 ** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set.
979 **
980 ** ^(SQLite will also add one of the following flags to the xOpen()
981 ** call, depending on the object being opened:
982 **
983 ** <ul>
984 ** <li> [SQLITE_OPEN_MAIN_DB]
985 ** <li> [SQLITE_OPEN_MAIN_JOURNAL]
986 ** <li> [SQLITE_OPEN_TEMP_DB]
987 ** <li> [SQLITE_OPEN_TEMP_JOURNAL]
988 ** <li> [SQLITE_OPEN_TRANSIENT_DB]
989 ** <li> [SQLITE_OPEN_SUBJOURNAL]
990 ** <li> [SQLITE_OPEN_MASTER_JOURNAL]
991 ** <li> [SQLITE_OPEN_WAL]
992 ** </ul>)^
993 **
994 ** The file I/O implementation can use the object type flags to
995 ** change the way it deals with files. For example, an application
996 ** that does not care about crash recovery or rollback might make
997 ** the open of a journal file a no-op. Writes to this journal would
998 ** also be no-ops, and any attempt to read the journal would return
999 ** SQLITE_IOERR. Or the implementation might recognize that a database
1000 ** file will be doing page-aligned sector reads and writes in a random
1001 ** order and set up its I/O subsystem accordingly.
1002 **
1003 ** SQLite might also add one of the following flags to the xOpen method:
1004 **
1005 ** <ul>
1006 ** <li> [SQLITE_OPEN_DELETEONCLOSE]
1007 ** <li> [SQLITE_OPEN_EXCLUSIVE]
1008 ** </ul>
1009 **
1010 ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
1011 ** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE]
1012 ** will be set for TEMP databases and their journals, transient
1013 ** databases, and subjournals.
1014 **
1015 ** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
1016 ** with the [SQLITE_OPEN_CREATE] flag, which are both directly
1017 ** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
1018 ** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
1019 ** SQLITE_OPEN_CREATE, is used to indicate that file should always
1020 ** be created, and that it is an error if it already exists.
1021 ** It is <i>not</i> used to indicate the file should be opened
1022 ** for exclusive access.
1023 **
1024 ** ^At least szOsFile bytes of memory are allocated by SQLite
1025 ** to hold the [sqlite3_file] structure passed as the third
1026 ** argument to xOpen. The xOpen method does not have to
1027 ** allocate the structure; it should just fill it in. Note that
1028 ** the xOpen method must set the sqlite3_file.pMethods to either
1029 ** a valid [sqlite3_io_methods] object or to NULL. xOpen must do
1030 ** this even if the open fails. SQLite expects that the sqlite3_file.pMethods
1031 ** element will be valid after xOpen returns regardless of the success
1032 ** or failure of the xOpen call.
1033 **
1034 ** [[sqlite3_vfs.xAccess]]
1035 ** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
1036 ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
1037 ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
1038 ** to test whether a file is at least readable. The file can be a
1039 ** directory.
1040 **
1041 ** ^SQLite will always allocate at least mxPathname+1 bytes for the
1042 ** output buffer xFullPathname. The exact size of the output buffer
1043 ** is also passed as a parameter to both methods. If the output buffer
1044 ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
1045 ** handled as a fatal error by SQLite, vfs implementations should endeavor
1046 ** to prevent this by setting mxPathname to a sufficiently large value.
1047 **
1048 ** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
1049 ** interfaces are not strictly a part of the filesystem, but they are
1050 ** included in the VFS structure for completeness.
1051 ** The xRandomness() function attempts to return nBytes bytes
1052 ** of good-quality randomness into zOut. The return value is
1053 ** the actual number of bytes of randomness obtained.
1054 ** The xSleep() method causes the calling thread to sleep for at
1055 ** least the number of microseconds given. ^The xCurrentTime()
1056 ** method returns a Julian Day Number for the current date and time as
1057 ** a floating point value.
1058 ** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
1059 ** Day Number multiplied by 86400000 (the number of milliseconds in
1060 ** a 24-hour day).
1061 ** ^SQLite will use the xCurrentTimeInt64() method to get the current
1062 ** date and time if that method is available (if iVersion is 2 or
1063 ** greater and the function pointer is not NULL) and will fall back
1064 ** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
1065 **
1066 ** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
1067 ** are not used by the SQLite core. These optional interfaces are provided
1068 ** by some VFSes to facilitate testing of the VFS code. By overriding
1069 ** system calls with functions under its control, a test program can
1070 ** simulate faults and error conditions that would otherwise be difficult
1071 ** or impossible to induce. The set of system calls that can be overridden
1072 ** varies from one VFS to another, and from one version of the same VFS to the
1073 ** next. Applications that use these interfaces must be prepared for any
1074 ** or all of these interfaces to be NULL or for their behavior to change
1075 ** from one release to the next. Applications must not attempt to access
1076 ** any of these methods if the iVersion of the VFS is less than 3.
1077 */
1078 typedef struct sqlite3_vfs sqlite3_vfs;
1079 typedef void (*sqlite3_syscall_ptr)(void);
1080 struct sqlite3_vfs {
1081 int iVersion; /* Structure version number (currently 3) */
1082 int szOsFile; /* Size of subclassed sqlite3_file */
1083 int mxPathname; /* Maximum file pathname length */
1084 sqlite3_vfs *pNext; /* Next registered VFS */
1085 const char *zName; /* Name of this virtual file system */
1086 void *pAppData; /* Pointer to application-specific data */
1087 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
1088 int flags, int *pOutFlags);
1089 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
1090 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
1091 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
1092 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
1093 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
1094 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
1095 void (*xDlClose)(sqlite3_vfs*, void*);
1096 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
1097 int (*xSleep)(sqlite3_vfs*, int microseconds);
1098 int (*xCurrentTime)(sqlite3_vfs*, double*);
1099 int (*xGetLastError)(sqlite3_vfs*, int, char *);
1100 /*
1101 ** The methods above are in version 1 of the sqlite_vfs object
1102 ** definition. Those that follow are added in version 2 or later
1103 */
1104 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
1105 /*
1106 ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
1107 ** Those below are for version 3 and greater.
1108 */
1109 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
1110 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
1111 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
1112 /*
1113 ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
1114 ** New fields may be appended in figure versions. The iVersion
1115 ** value will increment whenever this happens.
1116 */
1117 };
1118
1119 /*
1120 ** CAPI3REF: Flags for the xAccess VFS method
1121 **
1122 ** These integer constants can be used as the third parameter to
1123 ** the xAccess method of an [sqlite3_vfs] object. They determine
1124 ** what kind of permissions the xAccess method is looking for.
1125 ** With SQLITE_ACCESS_EXISTS, the xAccess method
1126 ** simply checks whether the file exists.
1127 ** With SQLITE_ACCESS_READWRITE, the xAccess method
1128 ** checks whether the named directory is both readable and writable
1129 ** (in other words, if files can be added, removed, and renamed within
1130 ** the directory).
1131 ** The SQLITE_ACCESS_READWRITE constant is currently used only by the
1132 ** [temp_store_directory pragma], though this could change in a future
1133 ** release of SQLite.
1134 ** With SQLITE_ACCESS_READ, the xAccess method
1135 ** checks whether the file is readable. The SQLITE_ACCESS_READ constant is
1136 ** currently unused, though it might be used in a future release of
1137 ** SQLite.
1138 */
1139 #define SQLITE_ACCESS_EXISTS 0
1140 #define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */
1141 #define SQLITE_ACCESS_READ 2 /* Unused */
1142
1143 /*
1144 ** CAPI3REF: Flags for the xShmLock VFS method
1145 **
1146 ** These integer constants define the various locking operations
1147 ** allowed by the xShmLock method of [sqlite3_io_methods]. The
1148 ** following are the only legal combinations of flags to the
1149 ** xShmLock method:
1150 **
1151 ** <ul>
1152 ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
1153 ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
1154 ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
1155 ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
1156 ** </ul>
1157 **
1158 ** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
1159 ** was given no the corresponding lock.
1160 **
1161 ** The xShmLock method can transition between unlocked and SHARED or
1162 ** between unlocked and EXCLUSIVE. It cannot transition between SHARED
1163 ** and EXCLUSIVE.
1164 */
1165 #define SQLITE_SHM_UNLOCK 1
1166 #define SQLITE_SHM_LOCK 2
1167 #define SQLITE_SHM_SHARED 4
1168 #define SQLITE_SHM_EXCLUSIVE 8
1169
1170 /*
1171 ** CAPI3REF: Maximum xShmLock index
1172 **
1173 ** The xShmLock method on [sqlite3_io_methods] may use values
1174 ** between 0 and this upper bound as its "offset" argument.
1175 ** The SQLite core will never attempt to acquire or release a
1176 ** lock outside of this range
1177 */
1178 #define SQLITE_SHM_NLOCK 8
1179
1180
1181 /*
1182 ** CAPI3REF: Initialize The SQLite Library
1183 **
1184 ** ^The sqlite3_initialize() routine initializes the
1185 ** SQLite library. ^The sqlite3_shutdown() routine
1186 ** deallocates any resources that were allocated by sqlite3_initialize().
1187 ** These routines are designed to aid in process initialization and
1188 ** shutdown on embedded systems. Workstation applications using
1189 ** SQLite normally do not need to invoke either of these routines.
1190 **
1191 ** A call to sqlite3_initialize() is an "effective" call if it is
1192 ** the first time sqlite3_initialize() is invoked during the lifetime of
1193 ** the process, or if it is the first time sqlite3_initialize() is invoked
1194 ** following a call to sqlite3_shutdown(). ^(Only an effective call
1195 ** of sqlite3_initialize() does any initialization. All other calls
1196 ** are harmless no-ops.)^
1197 **
1198 ** A call to sqlite3_shutdown() is an "effective" call if it is the first
1199 ** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only
1200 ** an effective call to sqlite3_shutdown() does any deinitialization.
1201 ** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
1202 **
1203 ** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
1204 ** is not. The sqlite3_shutdown() interface must only be called from a
1205 ** single thread. All open [database connections] must be closed and all
1206 ** other SQLite resources must be deallocated prior to invoking
1207 ** sqlite3_shutdown().
1208 **
1209 ** Among other things, ^sqlite3_initialize() will invoke
1210 ** sqlite3_os_init(). Similarly, ^sqlite3_shutdown()
1211 ** will invoke sqlite3_os_end().
1212 **
1213 ** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
1214 ** ^If for some reason, sqlite3_initialize() is unable to initialize
1215 ** the library (perhaps it is unable to allocate a needed resource such
1216 ** as a mutex) it returns an [error code] other than [SQLITE_OK].
1217 **
1218 ** ^The sqlite3_initialize() routine is called internally by many other
1219 ** SQLite interfaces so that an application usually does not need to
1220 ** invoke sqlite3_initialize() directly. For example, [sqlite3_open()]
1221 ** calls sqlite3_initialize() so the SQLite library will be automatically
1222 ** initialized when [sqlite3_open()] is called if it has not be initialized
1223 ** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
1224 ** compile-time option, then the automatic calls to sqlite3_initialize()
1225 ** are omitted and the application must call sqlite3_initialize() directly
1226 ** prior to using any other SQLite interface. For maximum portability,
1227 ** it is recommended that applications always invoke sqlite3_initialize()
1228 ** directly prior to using any other SQLite interface. Future releases
1229 ** of SQLite may require this. In other words, the behavior exhibited
1230 ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
1231 ** default behavior in some future release of SQLite.
1232 **
1233 ** The sqlite3_os_init() routine does operating-system specific
1234 ** initialization of the SQLite library. The sqlite3_os_end()
1235 ** routine undoes the effect of sqlite3_os_init(). Typical tasks
1236 ** performed by these routines include allocation or deallocation
1237 ** of static resources, initialization of global variables,
1238 ** setting up a default [sqlite3_vfs] module, or setting up
1239 ** a default configuration using [sqlite3_config()].
1240 **
1241 ** The application should never invoke either sqlite3_os_init()
1242 ** or sqlite3_os_end() directly. The application should only invoke
1243 ** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init()
1244 ** interface is called automatically by sqlite3_initialize() and
1245 ** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate
1246 ** implementations for sqlite3_os_init() and sqlite3_os_end()
1247 ** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
1248 ** When [custom builds | built for other platforms]
1249 ** (using the [SQLITE_OS_OTHER=1] compile-time
1250 ** option) the application must supply a suitable implementation for
1251 ** sqlite3_os_init() and sqlite3_os_end(). An application-supplied
1252 ** implementation of sqlite3_os_init() or sqlite3_os_end()
1253 ** must return [SQLITE_OK] on success and some other [error code] upon
1254 ** failure.
1255 */
1256 SQLITE_API int sqlite3_initialize(void);
1257 SQLITE_API int sqlite3_shutdown(void);
1258 SQLITE_API int sqlite3_os_init(void);
1259 SQLITE_API int sqlite3_os_end(void);
1260
1261 /*
1262 ** CAPI3REF: Configuring The SQLite Library
1263 **
1264 ** The sqlite3_config() interface is used to make global configuration
1265 ** changes to SQLite in order to tune SQLite to the specific needs of
1266 ** the application. The default configuration is recommended for most
1267 ** applications and so this routine is usually not necessary. It is
1268 ** provided to support rare applications with unusual needs.
1269 **
1270 ** The sqlite3_config() interface is not threadsafe. The application
1271 ** must insure that no other SQLite interfaces are invoked by other
1272 ** threads while sqlite3_config() is running. Furthermore, sqlite3_config()
1273 ** may only be invoked prior to library initialization using
1274 ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
1275 ** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
1276 ** [sqlite3_shutdown()] then it will return SQLITE_MISUSE.
1277 ** Note, however, that ^sqlite3_config() can be called as part of the
1278 ** implementation of an application-defined [sqlite3_os_init()].
1279 **
1280 ** The first argument to sqlite3_config() is an integer
1281 ** [configuration option] that determines
1282 ** what property of SQLite is to be configured. Subsequent arguments
1283 ** vary depending on the [configuration option]
1284 ** in the first argument.
1285 **
1286 ** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
1287 ** ^If the option is unknown or SQLite is unable to set the option
1288 ** then this routine returns a non-zero [error code].
1289 */
1290 SQLITE_API int sqlite3_config(int, ...);
1291
1292 /*
1293 ** CAPI3REF: Configure database connections
1294 **
1295 ** The sqlite3_db_config() interface is used to make configuration
1296 ** changes to a [database connection]. The interface is similar to
1297 ** [sqlite3_config()] except that the changes apply to a single
1298 ** [database connection] (specified in the first argument).
1299 **
1300 ** The second argument to sqlite3_db_config(D,V,...) is the
1301 ** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code
1302 ** that indicates what aspect of the [database connection] is being configured.
1303 ** Subsequent arguments vary depending on the configuration verb.
1304 **
1305 ** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
1306 ** the call is considered successful.
1307 */
1308 SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...);
1309
1310 /*
1311 ** CAPI3REF: Memory Allocation Routines
1312 **
1313 ** An instance of this object defines the interface between SQLite
1314 ** and low-level memory allocation routines.
1315 **
1316 ** This object is used in only one place in the SQLite interface.
1317 ** A pointer to an instance of this object is the argument to
1318 ** [sqlite3_config()] when the configuration option is
1319 ** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].
1320 ** By creating an instance of this object
1321 ** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
1322 ** during configuration, an application can specify an alternative
1323 ** memory allocation subsystem for SQLite to use for all of its
1324 ** dynamic memory needs.
1325 **
1326 ** Note that SQLite comes with several [built-in memory allocators]
1327 ** that are perfectly adequate for the overwhelming majority of applications
1328 ** and that this object is only useful to a tiny minority of applications
1329 ** with specialized memory allocation requirements. This object is
1330 ** also used during testing of SQLite in order to specify an alternative
1331 ** memory allocator that simulates memory out-of-memory conditions in
1332 ** order to verify that SQLite recovers gracefully from such
1333 ** conditions.
1334 **
1335 ** The xMalloc, xRealloc, and xFree methods must work like the
1336 ** malloc(), realloc() and free() functions from the standard C library.
1337 ** ^SQLite guarantees that the second argument to
1338 ** xRealloc is always a value returned by a prior call to xRoundup.
1339 **
1340 ** xSize should return the allocated size of a memory allocation
1341 ** previously obtained from xMalloc or xRealloc. The allocated size
1342 ** is always at least as big as the requested size but may be larger.
1343 **
1344 ** The xRoundup method returns what would be the allocated size of
1345 ** a memory allocation given a particular requested size. Most memory
1346 ** allocators round up memory allocations at least to the next multiple
1347 ** of 8. Some allocators round up to a larger multiple or to a power of 2.
1348 ** Every memory allocation request coming in through [sqlite3_malloc()]
1349 ** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0,
1350 ** that causes the corresponding memory allocation to fail.
1351 **
1352 ** The xInit method initializes the memory allocator. (For example,
1353 ** it might allocate any require mutexes or initialize internal data
1354 ** structures. The xShutdown method is invoked (indirectly) by
1355 ** [sqlite3_shutdown()] and should deallocate any resources acquired
1356 ** by xInit. The pAppData pointer is used as the only parameter to
1357 ** xInit and xShutdown.
1358 **
1359 ** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes
1360 ** the xInit method, so the xInit method need not be threadsafe. The
1361 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
1362 ** not need to be threadsafe either. For all other methods, SQLite
1363 ** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
1364 ** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
1365 ** it is by default) and so the methods are automatically serialized.
1366 ** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
1367 ** methods must be threadsafe or else make their own arrangements for
1368 ** serialization.
1369 **
1370 ** SQLite will never invoke xInit() more than once without an intervening
1371 ** call to xShutdown().
1372 */
1373 typedef struct sqlite3_mem_methods sqlite3_mem_methods;
1374 struct sqlite3_mem_methods {
1375 void *(*xMalloc)(int); /* Memory allocation function */
1376 void (*xFree)(void*); /* Free a prior allocation */
1377 void *(*xRealloc)(void*,int); /* Resize an allocation */
1378 int (*xSize)(void*); /* Return the size of an allocation */
1379 int (*xRoundup)(int); /* Round up request size to allocation size */
1380 int (*xInit)(void*); /* Initialize the memory allocator */
1381 void (*xShutdown)(void*); /* Deinitialize the memory allocator */
1382 void *pAppData; /* Argument to xInit() and xShutdown() */
1383 };
1384
1385 /*
1386 ** CAPI3REF: Configuration Options
1387 ** KEYWORDS: {configuration option}
1388 **
1389 ** These constants are the available integer configuration options that
1390 ** can be passed as the first argument to the [sqlite3_config()] interface.
1391 **
1392 ** New configuration options may be added in future releases of SQLite.
1393 ** Existing configuration options might be discontinued. Applications
1394 ** should check the return code from [sqlite3_config()] to make sure that
1395 ** the call worked. The [sqlite3_config()] interface will return a
1396 ** non-zero [error code] if a discontinued or unsupported configuration option
1397 ** is invoked.
1398 **
1399 ** <dl>
1400 ** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
1401 ** <dd>There are no arguments to this option. ^This option sets the
1402 ** [threading mode] to Single-thread. In other words, it disables
1403 ** all mutexing and puts SQLite into a mode where it can only be used
1404 ** by a single thread. ^If SQLite is compiled with
1405 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1406 ** it is not possible to change the [threading mode] from its default
1407 ** value of Single-thread and so [sqlite3_config()] will return
1408 ** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
1409 ** configuration option.</dd>
1410 **
1411 ** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt>
1412 ** <dd>There are no arguments to this option. ^This option sets the
1413 ** [threading mode] to Multi-thread. In other words, it disables
1414 ** mutexing on [database connection] and [prepared statement] objects.
1415 ** The application is responsible for serializing access to
1416 ** [database connections] and [prepared statements]. But other mutexes
1417 ** are enabled so that SQLite will be safe to use in a multi-threaded
1418 ** environment as long as no two threads attempt to use the same
1419 ** [database connection] at the same time. ^If SQLite is compiled with
1420 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1421 ** it is not possible to set the Multi-thread [threading mode] and
1422 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1423 ** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
1424 **
1425 ** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt>
1426 ** <dd>There are no arguments to this option. ^This option sets the
1427 ** [threading mode] to Serialized. In other words, this option enables
1428 ** all mutexes including the recursive
1429 ** mutexes on [database connection] and [prepared statement] objects.
1430 ** In this mode (which is the default when SQLite is compiled with
1431 ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
1432 ** to [database connections] and [prepared statements] so that the
1433 ** application is free to use the same [database connection] or the
1434 ** same [prepared statement] in different threads at the same time.
1435 ** ^If SQLite is compiled with
1436 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1437 ** it is not possible to set the Serialized [threading mode] and
1438 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1439 ** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
1440 **
1441 ** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt>
1442 ** <dd> ^(This option takes a single argument which is a pointer to an
1443 ** instance of the [sqlite3_mem_methods] structure. The argument specifies
1444 ** alternative low-level memory allocation routines to be used in place of
1445 ** the memory allocation routines built into SQLite.)^ ^SQLite makes
1446 ** its own private copy of the content of the [sqlite3_mem_methods] structure
1447 ** before the [sqlite3_config()] call returns.</dd>
1448 **
1449 ** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt>
1450 ** <dd> ^(This option takes a single argument which is a pointer to an
1451 ** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods]
1452 ** structure is filled with the currently defined memory allocation routines.)^
1453 ** This option can be used to overload the default memory allocation
1454 ** routines with a wrapper that simulations memory allocation failure or
1455 ** tracks memory usage, for example. </dd>
1456 **
1457 ** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt>
1458 ** <dd> ^This option takes single argument of type int, interpreted as a
1459 ** boolean, which enables or disables the collection of memory allocation
1460 ** statistics. ^(When memory allocation statistics are disabled, the
1461 ** following SQLite interfaces become non-operational:
1462 ** <ul>
1463 ** <li> [sqlite3_memory_used()]
1464 ** <li> [sqlite3_memory_highwater()]
1465 ** <li> [sqlite3_soft_heap_limit64()]
1466 ** <li> [sqlite3_status()]
1467 ** </ul>)^
1468 ** ^Memory allocation statistics are enabled by default unless SQLite is
1469 ** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
1470 ** allocation statistics are disabled by default.
1471 ** </dd>
1472 **
1473 ** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt>
1474 ** <dd> ^This option specifies a static memory buffer that SQLite can use for
1475 ** scratch memory. There are three arguments: A pointer an 8-byte
1476 ** aligned memory buffer from which the scratch allocations will be
1477 ** drawn, the size of each scratch allocation (sz),
1478 ** and the maximum number of scratch allocations (N). The sz
1479 ** argument must be a multiple of 16.
1480 ** The first argument must be a pointer to an 8-byte aligned buffer
1481 ** of at least sz*N bytes of memory.
1482 ** ^SQLite will use no more than two scratch buffers per thread. So
1483 ** N should be set to twice the expected maximum number of threads.
1484 ** ^SQLite will never require a scratch buffer that is more than 6
1485 ** times the database page size. ^If SQLite needs needs additional
1486 ** scratch memory beyond what is provided by this configuration option, then
1487 ** [sqlite3_malloc()] will be used to obtain the memory needed.</dd>
1488 **
1489 ** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>
1490 ** <dd> ^This option specifies a static memory buffer that SQLite can use for
1491 ** the database page cache with the default page cache implementation.
1492 ** This configuration should not be used if an application-define page
1493 ** cache implementation is loaded using the SQLITE_CONFIG_PCACHE2 option.
1494 ** There are three arguments to this option: A pointer to 8-byte aligned
1495 ** memory, the size of each page buffer (sz), and the number of pages (N).
1496 ** The sz argument should be the size of the largest database page
1497 ** (a power of two between 512 and 32768) plus a little extra for each
1498 ** page header. ^The page header size is 20 to 40 bytes depending on
1499 ** the host architecture. ^It is harmless, apart from the wasted memory,
1500 ** to make sz a little too large. The first
1501 ** argument should point to an allocation of at least sz*N bytes of memory.
1502 ** ^SQLite will use the memory provided by the first argument to satisfy its
1503 ** memory needs for the first N pages that it adds to cache. ^If additional
1504 ** page cache memory is needed beyond what is provided by this option, then
1505 ** SQLite goes to [sqlite3_malloc()] for the additional storage space.
1506 ** The pointer in the first argument must
1507 ** be aligned to an 8-byte boundary or subsequent behavior of SQLite
1508 ** will be undefined.</dd>
1509 **
1510 ** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt>
1511 ** <dd> ^This option specifies a static memory buffer that SQLite will use
1512 ** for all of its dynamic memory allocation needs beyond those provided
1513 ** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE].
1514 ** There are three arguments: An 8-byte aligned pointer to the memory,
1515 ** the number of bytes in the memory buffer, and the minimum allocation size.
1516 ** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
1517 ** to using its default memory allocator (the system malloc() implementation),
1518 ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the
1519 ** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or
1520 ** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory
1521 ** allocator is engaged to handle all of SQLites memory allocation needs.
1522 ** The first pointer (the memory pointer) must be aligned to an 8-byte
1523 ** boundary or subsequent behavior of SQLite will be undefined.
1524 ** The minimum allocation size is capped at 2**12. Reasonable values
1525 ** for the minimum allocation size are 2**5 through 2**8.</dd>
1526 **
1527 ** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt>
1528 ** <dd> ^(This option takes a single argument which is a pointer to an
1529 ** instance of the [sqlite3_mutex_methods] structure. The argument specifies
1530 ** alternative low-level mutex routines to be used in place
1531 ** the mutex routines built into SQLite.)^ ^SQLite makes a copy of the
1532 ** content of the [sqlite3_mutex_methods] structure before the call to
1533 ** [sqlite3_config()] returns. ^If SQLite is compiled with
1534 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1535 ** the entire mutexing subsystem is omitted from the build and hence calls to
1536 ** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
1537 ** return [SQLITE_ERROR].</dd>
1538 **
1539 ** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt>
1540 ** <dd> ^(This option takes a single argument which is a pointer to an
1541 ** instance of the [sqlite3_mutex_methods] structure. The
1542 ** [sqlite3_mutex_methods]
1543 ** structure is filled with the currently defined mutex routines.)^
1544 ** This option can be used to overload the default mutex allocation
1545 ** routines with a wrapper used to track mutex usage for performance
1546 ** profiling or testing, for example. ^If SQLite is compiled with
1547 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1548 ** the entire mutexing subsystem is omitted from the build and hence calls to
1549 ** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
1550 ** return [SQLITE_ERROR].</dd>
1551 **
1552 ** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt>
1553 ** <dd> ^(This option takes two arguments that determine the default
1554 ** memory allocation for the lookaside memory allocator on each
1555 ** [database connection]. The first argument is the
1556 ** size of each lookaside buffer slot and the second is the number of
1557 ** slots allocated to each database connection.)^ ^(This option sets the
1558 ** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
1559 ** verb to [sqlite3_db_config()] can be used to change the lookaside
1560 ** configuration on individual connections.)^ </dd>
1561 **
1562 ** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt>
1563 ** <dd> ^(This option takes a single argument which is a pointer to
1564 ** an [sqlite3_pcache_methods2] object. This object specifies the interface
1565 ** to a custom page cache implementation.)^ ^SQLite makes a copy of the
1566 ** object and uses it for page cache memory allocations.</dd>
1567 **
1568 ** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt>
1569 ** <dd> ^(This option takes a single argument which is a pointer to an
1570 ** [sqlite3_pcache_methods2] object. SQLite copies of the current
1571 ** page cache implementation into that object.)^ </dd>
1572 **
1573 ** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>
1574 ** <dd> ^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
1575 ** function with a call signature of void(*)(void*,int,const char*),
1576 ** and a pointer to void. ^If the function pointer is not NULL, it is
1577 ** invoked by [sqlite3_log()] to process each logging event. ^If the
1578 ** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
1579 ** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
1580 ** passed through as the first parameter to the application-defined logger
1581 ** function whenever that function is invoked. ^The second parameter to
1582 ** the logger function is a copy of the first parameter to the corresponding
1583 ** [sqlite3_log()] call and is intended to be a [result code] or an
1584 ** [extended result code]. ^The third parameter passed to the logger is
1585 ** log message after formatting via [sqlite3_snprintf()].
1586 ** The SQLite logging interface is not reentrant; the logger function
1587 ** supplied by the application must not invoke any SQLite interface.
1588 ** In a multi-threaded application, the application-defined logger
1589 ** function must be threadsafe. </dd>
1590 **
1591 ** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI
1592 ** <dd> This option takes a single argument of type int. If non-zero, then
1593 ** URI handling is globally enabled. If the parameter is zero, then URI handling
1594 ** is globally disabled. If URI handling is globally enabled, all filenames
1595 ** passed to [sqlite3_open()], [sqlite3_open_v2()], [sqlite3_open16()] or
1596 ** specified as part of [ATTACH] commands are interpreted as URIs, regardless
1597 ** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
1598 ** connection is opened. If it is globally disabled, filenames are
1599 ** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
1600 ** database connection is opened. By default, URI handling is globally
1601 ** disabled. The default value may be changed by compiling with the
1602 ** [SQLITE_USE_URI] symbol defined.
1603 **
1604 ** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN
1605 ** <dd> This option takes a single integer argument which is interpreted as
1606 ** a boolean in order to enable or disable the use of covering indices for
1607 ** full table scans in the query optimizer. The default setting is determined
1608 ** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on"
1609 ** if that compile-time option is omitted.
1610 ** The ability to disable the use of covering indices for full table scans
1611 ** is because some incorrectly coded legacy applications might malfunction
1612 ** malfunction when the optimization is enabled. Providing the ability to
1613 ** disable the optimization allows the older, buggy application code to work
1614 ** without change even with newer versions of SQLite.
1615 **
1616 ** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]]
1617 ** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE
1618 ** <dd> These options are obsolete and should not be used by new code.
1619 ** They are retained for backwards compatibility but are now no-ops.
1620 ** </dl>
1621 **
1622 ** [[SQLITE_CONFIG_SQLLOG]]
1623 ** <dt>SQLITE_CONFIG_SQLLOG
1624 ** <dd>This option is only available if sqlite is compiled with the
1625 ** SQLITE_ENABLE_SQLLOG pre-processor macro defined. The first argument should
1626 ** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int).
1627 ** The second should be of type (void*). The callback is invoked by the library
1628 ** in three separate circumstances, identified by the value passed as the
1629 ** fourth parameter. If the fourth parameter is 0, then the database connection
1630 ** passed as the second argument has just been opened. The third argument
1631 ** points to a buffer containing the name of the main database file. If the
1632 ** fourth parameter is 1, then the SQL statement that the third parameter
1633 ** points to has just been executed. Or, if the fourth parameter is 2, then
1634 ** the connection being passed as the second parameter is being closed. The
1635 ** third parameter is passed NULL In this case.
1636 ** </dl>
1637 */
1638 #define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */
1639 #define SQLITE_CONFIG_MULTITHREAD 2 /* nil */
1640 #define SQLITE_CONFIG_SERIALIZED 3 /* nil */
1641 #define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */
1642 #define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */
1643 #define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */
1644 #define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */
1645 #define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */
1646 #define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */
1647 #define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */
1648 #define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */
1649 /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */
1650 #define SQLITE_CONFIG_LOOKASIDE 13 /* int int */
1651 #define SQLITE_CONFIG_PCACHE 14 /* no-op */
1652 #define SQLITE_CONFIG_GETPCACHE 15 /* no-op */
1653 #define SQLITE_CONFIG_LOG 16 /* xFunc, void* */
1654 #define SQLITE_CONFIG_URI 17 /* int */
1655 #define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */
1656 #define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */
1657 #define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */
1658 #define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */
1659
1660 /*
1661 ** CAPI3REF: Database Connection Configuration Options
1662 **
1663 ** These constants are the available integer configuration options that
1664 ** can be passed as the second argument to the [sqlite3_db_config()] interface.
1665 **
1666 ** New configuration options may be added in future releases of SQLite.
1667 ** Existing configuration options might be discontinued. Applications
1668 ** should check the return code from [sqlite3_db_config()] to make sure that
1669 ** the call worked. ^The [sqlite3_db_config()] interface will return a
1670 ** non-zero [error code] if a discontinued or unsupported configuration option
1671 ** is invoked.
1672 **
1673 ** <dl>
1674 ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
1675 ** <dd> ^This option takes three additional arguments that determine the
1676 ** [lookaside memory allocator] configuration for the [database connection].
1677 ** ^The first argument (the third parameter to [sqlite3_db_config()] is a
1678 ** pointer to a memory buffer to use for lookaside memory.
1679 ** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
1680 ** may be NULL in which case SQLite will allocate the
1681 ** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
1682 ** size of each lookaside buffer slot. ^The third argument is the number of
1683 ** slots. The size of the buffer in the first argument must be greater than
1684 ** or equal to the product of the second and third arguments. The buffer
1685 ** must be aligned to an 8-byte boundary. ^If the second argument to
1686 ** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
1687 ** rounded down to the next smaller multiple of 8. ^(The lookaside memory
1688 ** configuration for a database connection can only be changed when that
1689 ** connection is not currently using lookaside memory, or in other words
1690 ** when the "current value" returned by
1691 ** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero.
1692 ** Any attempt to change the lookaside memory configuration when lookaside
1693 ** memory is in use leaves the configuration unchanged and returns
1694 ** [SQLITE_BUSY].)^</dd>
1695 **
1696 ** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
1697 ** <dd> ^This option is used to enable or disable the enforcement of
1698 ** [foreign key constraints]. There should be two additional arguments.
1699 ** The first argument is an integer which is 0 to disable FK enforcement,
1700 ** positive to enable FK enforcement or negative to leave FK enforcement
1701 ** unchanged. The second parameter is a pointer to an integer into which
1702 ** is written 0 or 1 to indicate whether FK enforcement is off or on
1703 ** following this call. The second parameter may be a NULL pointer, in
1704 ** which case the FK enforcement setting is not reported back. </dd>
1705 **
1706 ** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
1707 ** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
1708 ** There should be two additional arguments.
1709 ** The first argument is an integer which is 0 to disable triggers,
1710 ** positive to enable triggers or negative to leave the setting unchanged.
1711 ** The second parameter is a pointer to an integer into which
1712 ** is written 0 or 1 to indicate whether triggers are disabled or enabled
1713 ** following this call. The second parameter may be a NULL pointer, in
1714 ** which case the trigger setting is not reported back. </dd>
1715 **
1716 ** </dl>
1717 */
1718 #define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */
1719 #define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */
1720 #define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */
1721
1722
1723 /*
1724 ** CAPI3REF: Enable Or Disable Extended Result Codes
1725 **
1726 ** ^The sqlite3_extended_result_codes() routine enables or disables the
1727 ** [extended result codes] feature of SQLite. ^The extended result
1728 ** codes are disabled by default for historical compatibility.
1729 */
1730 SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff);
1731
1732 /*
1733 ** CAPI3REF: Last Insert Rowid
1734 **
1735 ** ^Each entry in an SQLite table has a unique 64-bit signed
1736 ** integer key called the [ROWID | "rowid"]. ^The rowid is always available
1737 ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
1738 ** names are not also used by explicitly declared columns. ^If
1739 ** the table has a column of type [INTEGER PRIMARY KEY] then that column
1740 ** is another alias for the rowid.
1741 **
1742 ** ^This routine returns the [rowid] of the most recent
1743 ** successful [INSERT] into the database from the [database connection]
1744 ** in the first argument. ^As of SQLite version 3.7.7, this routines
1745 ** records the last insert rowid of both ordinary tables and [virtual tables].
1746 ** ^If no successful [INSERT]s
1747 ** have ever occurred on that database connection, zero is returned.
1748 **
1749 ** ^(If an [INSERT] occurs within a trigger or within a [virtual table]
1750 ** method, then this routine will return the [rowid] of the inserted
1751 ** row as long as the trigger or virtual table method is running.
1752 ** But once the trigger or virtual table method ends, the value returned
1753 ** by this routine reverts to what it was before the trigger or virtual
1754 ** table method began.)^
1755 **
1756 ** ^An [INSERT] that fails due to a constraint violation is not a
1757 ** successful [INSERT] and does not change the value returned by this
1758 ** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
1759 ** and INSERT OR ABORT make no changes to the return value of this
1760 ** routine when their insertion fails. ^(When INSERT OR REPLACE
1761 ** encounters a constraint violation, it does not fail. The
1762 ** INSERT continues to completion after deleting rows that caused
1763 ** the constraint problem so INSERT OR REPLACE will always change
1764 ** the return value of this interface.)^
1765 **
1766 ** ^For the purposes of this routine, an [INSERT] is considered to
1767 ** be successful even if it is subsequently rolled back.
1768 **
1769 ** This function is accessible to SQL statements via the
1770 ** [last_insert_rowid() SQL function].
1771 **
1772 ** If a separate thread performs a new [INSERT] on the same
1773 ** database connection while the [sqlite3_last_insert_rowid()]
1774 ** function is running and thus changes the last insert [rowid],
1775 ** then the value returned by [sqlite3_last_insert_rowid()] is
1776 ** unpredictable and might not equal either the old or the new
1777 ** last insert [rowid].
1778 */
1779 SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
1780
1781 /*
1782 ** CAPI3REF: Count The Number Of Rows Modified
1783 **
1784 ** ^This function returns the number of database rows that were changed
1785 ** or inserted or deleted by the most recently completed SQL statement
1786 ** on the [database connection] specified by the first parameter.
1787 ** ^(Only changes that are directly specified by the [INSERT], [UPDATE],
1788 ** or [DELETE] statement are counted. Auxiliary changes caused by
1789 ** triggers or [foreign key actions] are not counted.)^ Use the
1790 ** [sqlite3_total_changes()] function to find the total number of changes
1791 ** including changes caused by triggers and foreign key actions.
1792 **
1793 ** ^Changes to a view that are simulated by an [INSTEAD OF trigger]
1794 ** are not counted. Only real table changes are counted.
1795 **
1796 ** ^(A "row change" is a change to a single row of a single table
1797 ** caused by an INSERT, DELETE, or UPDATE statement. Rows that
1798 ** are changed as side effects of [REPLACE] constraint resolution,
1799 ** rollback, ABORT processing, [DROP TABLE], or by any other
1800 ** mechanisms do not count as direct row changes.)^
1801 **
1802 ** A "trigger context" is a scope of execution that begins and
1803 ** ends with the script of a [CREATE TRIGGER | trigger].
1804 ** Most SQL statements are
1805 ** evaluated outside of any trigger. This is the "top level"
1806 ** trigger context. If a trigger fires from the top level, a
1807 ** new trigger context is entered for the duration of that one
1808 ** trigger. Subtriggers create subcontexts for their duration.
1809 **
1810 ** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does
1811 ** not create a new trigger context.
1812 **
1813 ** ^This function returns the number of direct row changes in the
1814 ** most recent INSERT, UPDATE, or DELETE statement within the same
1815 ** trigger context.
1816 **
1817 ** ^Thus, when called from the top level, this function returns the
1818 ** number of changes in the most recent INSERT, UPDATE, or DELETE
1819 ** that also occurred at the top level. ^(Within the body of a trigger,
1820 ** the sqlite3_changes() interface can be called to find the number of
1821 ** changes in the most recently completed INSERT, UPDATE, or DELETE
1822 ** statement within the body of the same trigger.
1823 ** However, the number returned does not include changes
1824 ** caused by subtriggers since those have their own context.)^
1825 **
1826 ** See also the [sqlite3_total_changes()] interface, the
1827 ** [count_changes pragma], and the [changes() SQL function].
1828 **
1829 ** If a separate thread makes changes on the same database connection
1830 ** while [sqlite3_changes()] is running then the value returned
1831 ** is unpredictable and not meaningful.
1832 */
1833 SQLITE_API int sqlite3_changes(sqlite3*);
1834
1835 /*
1836 ** CAPI3REF: Total Number Of Rows Modified
1837 **
1838 ** ^This function returns the number of row changes caused by [INSERT],
1839 ** [UPDATE] or [DELETE] statements since the [database connection] was opened.
1840 ** ^(The count returned by sqlite3_total_changes() includes all changes
1841 ** from all [CREATE TRIGGER | trigger] contexts and changes made by
1842 ** [foreign key actions]. However,
1843 ** the count does not include changes used to implement [REPLACE] constraints,
1844 ** do rollbacks or ABORT processing, or [DROP TABLE] processing. The
1845 ** count does not include rows of views that fire an [INSTEAD OF trigger],
1846 ** though if the INSTEAD OF trigger makes changes of its own, those changes
1847 ** are counted.)^
1848 ** ^The sqlite3_total_changes() function counts the changes as soon as
1849 ** the statement that makes them is completed (when the statement handle
1850 ** is passed to [sqlite3_reset()] or [sqlite3_finalize()]).
1851 **
1852 ** See also the [sqlite3_changes()] interface, the
1853 ** [count_changes pragma], and the [total_changes() SQL function].
1854 **
1855 ** If a separate thread makes changes on the same database connection
1856 ** while [sqlite3_total_changes()] is running then the value
1857 ** returned is unpredictable and not meaningful.
1858 */
1859 SQLITE_API int sqlite3_total_changes(sqlite3*);
1860
1861 /*
1862 ** CAPI3REF: Interrupt A Long-Running Query
1863 **
1864 ** ^This function causes any pending database operation to abort and
1865 ** return at its earliest opportunity. This routine is typically
1866 ** called in response to a user action such as pressing "Cancel"
1867 ** or Ctrl-C where the user wants a long query operation to halt
1868 ** immediately.
1869 **
1870 ** ^It is safe to call this routine from a thread different from the
1871 ** thread that is currently running the database operation. But it
1872 ** is not safe to call this routine with a [database connection] that
1873 ** is closed or might close before sqlite3_interrupt() returns.
1874 **
1875 ** ^If an SQL operation is very nearly finished at the time when
1876 ** sqlite3_interrupt() is called, then it might not have an opportunity
1877 ** to be interrupted and might continue to completion.
1878 **
1879 ** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
1880 ** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
1881 ** that is inside an explicit transaction, then the entire transaction
1882 ** will be rolled back automatically.
1883 **
1884 ** ^The sqlite3_interrupt(D) call is in effect until all currently running
1885 ** SQL statements on [database connection] D complete. ^Any new SQL statements
1886 ** that are started after the sqlite3_interrupt() call and before the
1887 ** running statements reaches zero are interrupted as if they had been
1888 ** running prior to the sqlite3_interrupt() call. ^New SQL statements
1889 ** that are started after the running statement count reaches zero are
1890 ** not effected by the sqlite3_interrupt().
1891 ** ^A call to sqlite3_interrupt(D) that occurs when there are no running
1892 ** SQL statements is a no-op and has no effect on SQL statements
1893 ** that are started after the sqlite3_interrupt() call returns.
1894 **
1895 ** If the database connection closes while [sqlite3_interrupt()]
1896 ** is running then bad things will likely happen.
1897 */
1898 SQLITE_API void sqlite3_interrupt(sqlite3*);
1899
1900 /*
1901 ** CAPI3REF: Determine If An SQL Statement Is Complete
1902 **
1903 ** These routines are useful during command-line input to determine if the
1904 ** currently entered text seems to form a complete SQL statement or
1905 ** if additional input is needed before sending the text into
1906 ** SQLite for parsing. ^These routines return 1 if the input string
1907 ** appears to be a complete SQL statement. ^A statement is judged to be
1908 ** complete if it ends with a semicolon token and is not a prefix of a
1909 ** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within
1910 ** string literals or quoted identifier names or comments are not
1911 ** independent tokens (they are part of the token in which they are
1912 ** embedded) and thus do not count as a statement terminator. ^Whitespace
1913 ** and comments that follow the final semicolon are ignored.
1914 **
1915 ** ^These routines return 0 if the statement is incomplete. ^If a
1916 ** memory allocation fails, then SQLITE_NOMEM is returned.
1917 **
1918 ** ^These routines do not parse the SQL statements thus
1919 ** will not detect syntactically incorrect SQL.
1920 **
1921 ** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior
1922 ** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
1923 ** automatically by sqlite3_complete16(). If that initialization fails,
1924 ** then the return value from sqlite3_complete16() will be non-zero
1925 ** regardless of whether or not the input SQL is complete.)^
1926 **
1927 ** The input to [sqlite3_complete()] must be a zero-terminated
1928 ** UTF-8 string.
1929 **
1930 ** The input to [sqlite3_complete16()] must be a zero-terminated
1931 ** UTF-16 string in native byte order.
1932 */
1933 SQLITE_API int sqlite3_complete(const char *sql);
1934 SQLITE_API int sqlite3_complete16(const void *sql);
1935
1936 /*
1937 ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
1938 **
1939 ** ^This routine sets a callback function that might be invoked whenever
1940 ** an attempt is made to open a database table that another thread
1941 ** or process has locked.
1942 **
1943 ** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]
1944 ** is returned immediately upon encountering the lock. ^If the busy callback
1945 ** is not NULL, then the callback might be invoked with two arguments.
1946 **
1947 ** ^The first argument to the busy handler is a copy of the void* pointer which
1948 ** is the third argument to sqlite3_busy_handler(). ^The second argument to
1949 ** the busy handler callback is the number of times that the busy handler has
1950 ** been invoked for this locking event. ^If the
1951 ** busy callback returns 0, then no additional attempts are made to
1952 ** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned.
1953 ** ^If the callback returns non-zero, then another attempt
1954 ** is made to open the database for reading and the cycle repeats.
1955 **
1956 ** The presence of a busy handler does not guarantee that it will be invoked
1957 ** when there is lock contention. ^If SQLite determines that invoking the busy
1958 ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
1959 ** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler.
1960 ** Consider a scenario where one process is holding a read lock that
1961 ** it is trying to promote to a reserved lock and
1962 ** a second process is holding a reserved lock that it is trying
1963 ** to promote to an exclusive lock. The first process cannot proceed
1964 ** because it is blocked by the second and the second process cannot
1965 ** proceed because it is blocked by the first. If both processes
1966 ** invoke the busy handlers, neither will make any progress. Therefore,
1967 ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
1968 ** will induce the first process to release its read lock and allow
1969 ** the second process to proceed.
1970 **
1971 ** ^The default busy callback is NULL.
1972 **
1973 ** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED]
1974 ** when SQLite is in the middle of a large transaction where all the
1975 ** changes will not fit into the in-memory cache. SQLite will
1976 ** already hold a RESERVED lock on the database file, but it needs
1977 ** to promote this lock to EXCLUSIVE so that it can spill cache
1978 ** pages into the database file without harm to concurrent
1979 ** readers. ^If it is unable to promote the lock, then the in-memory
1980 ** cache will be left in an inconsistent state and so the error
1981 ** code is promoted from the relatively benign [SQLITE_BUSY] to
1982 ** the more severe [SQLITE_IOERR_BLOCKED]. ^This error code promotion
1983 ** forces an automatic rollback of the changes. See the
1984 ** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError">
1985 ** CorruptionFollowingBusyError</a> wiki page for a discussion of why
1986 ** this is important.
1987 **
1988 ** ^(There can only be a single busy handler defined for each
1989 ** [database connection]. Setting a new busy handler clears any
1990 ** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()]
1991 ** will also set or clear the busy handler.
1992 **
1993 ** The busy callback should not take any actions which modify the
1994 ** database connection that invoked the busy handler. Any such actions
1995 ** result in undefined behavior.
1996 **
1997 ** A busy handler must not close the database connection
1998 ** or [prepared statement] that invoked the busy handler.
1999 */
2000 SQLITE_API int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*);
2001
2002 /*
2003 ** CAPI3REF: Set A Busy Timeout
2004 **
2005 ** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
2006 ** for a specified amount of time when a table is locked. ^The handler
2007 ** will sleep multiple times until at least "ms" milliseconds of sleeping
2008 ** have accumulated. ^After at least "ms" milliseconds of sleeping,
2009 ** the handler returns 0 which causes [sqlite3_step()] to return
2010 ** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED].
2011 **
2012 ** ^Calling this routine with an argument less than or equal to zero
2013 ** turns off all busy handlers.
2014 **
2015 ** ^(There can only be a single busy handler for a particular
2016 ** [database connection] any any given moment. If another busy handler
2017 ** was defined (using [sqlite3_busy_handler()]) prior to calling
2018 ** this routine, that other busy handler is cleared.)^
2019 */
2020 SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms);
2021
2022 /*
2023 ** CAPI3REF: Convenience Routines For Running Queries
2024 **
2025 ** This is a legacy interface that is preserved for backwards compatibility.
2026 ** Use of this interface is not recommended.
2027 **
2028 ** Definition: A <b>result table</b> is memory data structure created by the
2029 ** [sqlite3_get_table()] interface. A result table records the
2030 ** complete query results from one or more queries.
2031 **
2032 ** The table conceptually has a number of rows and columns. But
2033 ** these numbers are not part of the result table itself. These
2034 ** numbers are obtained separately. Let N be the number of rows
2035 ** and M be the number of columns.
2036 **
2037 ** A result table is an array of pointers to zero-terminated UTF-8 strings.
2038 ** There are (N+1)*M elements in the array. The first M pointers point
2039 ** to zero-terminated strings that contain the names of the columns.
2040 ** The remaining entries all point to query results. NULL values result
2041 ** in NULL pointers. All other values are in their UTF-8 zero-terminated
2042 ** string representation as returned by [sqlite3_column_text()].
2043 **
2044 ** A result table might consist of one or more memory allocations.
2045 ** It is not safe to pass a result table directly to [sqlite3_free()].
2046 ** A result table should be deallocated using [sqlite3_free_table()].
2047 **
2048 ** ^(As an example of the result table format, suppose a query result
2049 ** is as follows:
2050 **
2051 ** <blockquote><pre>
2052 ** Name | Age
2053 ** -----------------------
2054 ** Alice | 43
2055 ** Bob | 28
2056 ** Cindy | 21
2057 ** </pre></blockquote>
2058 **
2059 ** There are two column (M==2) and three rows (N==3). Thus the
2060 ** result table has 8 entries. Suppose the result table is stored
2061 ** in an array names azResult. Then azResult holds this content:
2062 **
2063 ** <blockquote><pre>
2064 ** azResult&#91;0] = "Name";
2065 ** azResult&#91;1] = "Age";
2066 ** azResult&#91;2] = "Alice";
2067 ** azResult&#91;3] = "43";
2068 ** azResult&#91;4] = "Bob";
2069 ** azResult&#91;5] = "28";
2070 ** azResult&#91;6] = "Cindy";
2071 ** azResult&#91;7] = "21";
2072 ** </pre></blockquote>)^
2073 **
2074 ** ^The sqlite3_get_table() function evaluates one or more
2075 ** semicolon-separated SQL statements in the zero-terminated UTF-8
2076 ** string of its 2nd parameter and returns a result table to the
2077 ** pointer given in its 3rd parameter.
2078 **
2079 ** After the application has finished with the result from sqlite3_get_table(),
2080 ** it must pass the result table pointer to sqlite3_free_table() in order to
2081 ** release the memory that was malloced. Because of the way the
2082 ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
2083 ** function must not try to call [sqlite3_free()] directly. Only
2084 ** [sqlite3_free_table()] is able to release the memory properly and safely.
2085 **
2086 ** The sqlite3_get_table() interface is implemented as a wrapper around
2087 ** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access
2088 ** to any internal data structures of SQLite. It uses only the public
2089 ** interface defined here. As a consequence, errors that occur in the
2090 ** wrapper layer outside of the internal [sqlite3_exec()] call are not
2091 ** reflected in subsequent calls to [sqlite3_errcode()] or
2092 ** [sqlite3_errmsg()].
2093 */
2094 SQLITE_API int sqlite3_get_table(
2095 sqlite3 *db, /* An open database */
2096 const char *zSql, /* SQL to be evaluated */
2097 char ***pazResult, /* Results of the query */
2098 int *pnRow, /* Number of result rows written here */
2099 int *pnColumn, /* Number of result columns written here */
2100 char **pzErrmsg /* Error msg written here */
2101 );
2102 SQLITE_API void sqlite3_free_table(char **result);
2103
2104 /*
2105 ** CAPI3REF: Formatted String Printing Functions
2106 **
2107 ** These routines are work-alikes of the "printf()" family of functions
2108 ** from the standard C library.
2109 **
2110 ** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
2111 ** results into memory obtained from [sqlite3_malloc()].
2112 ** The strings returned by these two routines should be
2113 ** released by [sqlite3_free()]. ^Both routines return a
2114 ** NULL pointer if [sqlite3_malloc()] is unable to allocate enough
2115 ** memory to hold the resulting string.
2116 **
2117 ** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
2118 ** the standard C library. The result is written into the
2119 ** buffer supplied as the second parameter whose size is given by
2120 ** the first parameter. Note that the order of the
2121 ** first two parameters is reversed from snprintf().)^ This is an
2122 ** historical accident that cannot be fixed without breaking
2123 ** backwards compatibility. ^(Note also that sqlite3_snprintf()
2124 ** returns a pointer to its buffer instead of the number of
2125 ** characters actually written into the buffer.)^ We admit that
2126 ** the number of characters written would be a more useful return
2127 ** value but we cannot change the implementation of sqlite3_snprintf()
2128 ** now without breaking compatibility.
2129 **
2130 ** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
2131 ** guarantees that the buffer is always zero-terminated. ^The first
2132 ** parameter "n" is the total size of the buffer, including space for
2133 ** the zero terminator. So the longest string that can be completely
2134 ** written will be n-1 characters.
2135 **
2136 ** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
2137 **
2138 ** These routines all implement some additional formatting
2139 ** options that are useful for constructing SQL statements.
2140 ** All of the usual printf() formatting options apply. In addition, there
2141 ** is are "%q", "%Q", and "%z" options.
2142 **
2143 ** ^(The %q option works like %s in that it substitutes a nul-terminated
2144 ** string from the argument list. But %q also doubles every '\'' character.
2145 ** %q is designed for use inside a string literal.)^ By doubling each '\''
2146 ** character it escapes that character and allows it to be inserted into
2147 ** the string.
2148 **
2149 ** For example, assume the string variable zText contains text as follows:
2150 **
2151 ** <blockquote><pre>
2152 ** char *zText = "It's a happy day!";
2153 ** </pre></blockquote>
2154 **
2155 ** One can use this text in an SQL statement as follows:
2156 **
2157 ** <blockquote><pre>
2158 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText);
2159 ** sqlite3_exec(db, zSQL, 0, 0, 0);
2160 ** sqlite3_free(zSQL);
2161 ** </pre></blockquote>
2162 **
2163 ** Because the %q format string is used, the '\'' character in zText
2164 ** is escaped and the SQL generated is as follows:
2165 **
2166 ** <blockquote><pre>
2167 ** INSERT INTO table1 VALUES('It''s a happy day!')
2168 ** </pre></blockquote>
2169 **
2170 ** This is correct. Had we used %s instead of %q, the generated SQL
2171 ** would have looked like this:
2172 **
2173 ** <blockquote><pre>
2174 ** INSERT INTO table1 VALUES('It's a happy day!');
2175 ** </pre></blockquote>
2176 **
2177 ** This second example is an SQL syntax error. As a general rule you should
2178 ** always use %q instead of %s when inserting text into a string literal.
2179 **
2180 ** ^(The %Q option works like %q except it also adds single quotes around
2181 ** the outside of the total string. Additionally, if the parameter in the
2182 ** argument list is a NULL pointer, %Q substitutes the text "NULL" (without
2183 ** single quotes).)^ So, for example, one could say:
2184 **
2185 ** <blockquote><pre>
2186 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText);
2187 ** sqlite3_exec(db, zSQL, 0, 0, 0);
2188 ** sqlite3_free(zSQL);
2189 ** </pre></blockquote>
2190 **
2191 ** The code above will render a correct SQL statement in the zSQL
2192 ** variable even if the zText variable is a NULL pointer.
2193 **
2194 ** ^(The "%z" formatting option works like "%s" but with the
2195 ** addition that after the string has been read and copied into
2196 ** the result, [sqlite3_free()] is called on the input string.)^
2197 */
2198 SQLITE_API char *sqlite3_mprintf(const char*,...);
2199 SQLITE_API char *sqlite3_vmprintf(const char*, va_list);
2200 SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...);
2201 SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list);
2202
2203 /*
2204 ** CAPI3REF: Memory Allocation Subsystem
2205 **
2206 ** The SQLite core uses these three routines for all of its own
2207 ** internal memory allocation needs. "Core" in the previous sentence
2208 ** does not include operating-system specific VFS implementation. The
2209 ** Windows VFS uses native malloc() and free() for some operations.
2210 **
2211 ** ^The sqlite3_malloc() routine returns a pointer to a block
2212 ** of memory at least N bytes in length, where N is the parameter.
2213 ** ^If sqlite3_malloc() is unable to obtain sufficient free
2214 ** memory, it returns a NULL pointer. ^If the parameter N to
2215 ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
2216 ** a NULL pointer.
2217 **
2218 ** ^Calling sqlite3_free() with a pointer previously returned
2219 ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
2220 ** that it might be reused. ^The sqlite3_free() routine is
2221 ** a no-op if is called with a NULL pointer. Passing a NULL pointer
2222 ** to sqlite3_free() is harmless. After being freed, memory
2223 ** should neither be read nor written. Even reading previously freed
2224 ** memory might result in a segmentation fault or other severe error.
2225 ** Memory corruption, a segmentation fault, or other severe error
2226 ** might result if sqlite3_free() is called with a non-NULL pointer that
2227 ** was not obtained from sqlite3_malloc() or sqlite3_realloc().
2228 **
2229 ** ^(The sqlite3_realloc() interface attempts to resize a
2230 ** prior memory allocation to be at least N bytes, where N is the
2231 ** second parameter. The memory allocation to be resized is the first
2232 ** parameter.)^ ^ If the first parameter to sqlite3_realloc()
2233 ** is a NULL pointer then its behavior is identical to calling
2234 ** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc().
2235 ** ^If the second parameter to sqlite3_realloc() is zero or
2236 ** negative then the behavior is exactly the same as calling
2237 ** sqlite3_free(P) where P is the first parameter to sqlite3_realloc().
2238 ** ^sqlite3_realloc() returns a pointer to a memory allocation
2239 ** of at least N bytes in size or NULL if sufficient memory is unavailable.
2240 ** ^If M is the size of the prior allocation, then min(N,M) bytes
2241 ** of the prior allocation are copied into the beginning of buffer returned
2242 ** by sqlite3_realloc() and the prior allocation is freed.
2243 ** ^If sqlite3_realloc() returns NULL, then the prior allocation
2244 ** is not freed.
2245 **
2246 ** ^The memory returned by sqlite3_malloc() and sqlite3_realloc()
2247 ** is always aligned to at least an 8 byte boundary, or to a
2248 ** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
2249 ** option is used.
2250 **
2251 ** In SQLite version 3.5.0 and 3.5.1, it was possible to define
2252 ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in
2253 ** implementation of these routines to be omitted. That capability
2254 ** is no longer provided. Only built-in memory allocators can be used.
2255 **
2256 ** Prior to SQLite version 3.7.10, the Windows OS interface layer called
2257 ** the system malloc() and free() directly when converting
2258 ** filenames between the UTF-8 encoding used by SQLite
2259 ** and whatever filename encoding is used by the particular Windows
2260 ** installation. Memory allocation errors were detected, but
2261 ** they were reported back as [SQLITE_CANTOPEN] or
2262 ** [SQLITE_IOERR] rather than [SQLITE_NOMEM].
2263 **
2264 ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
2265 ** must be either NULL or else pointers obtained from a prior
2266 ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
2267 ** not yet been released.
2268 **
2269 ** The application must not read or write any part of
2270 ** a block of memory after it has been released using
2271 ** [sqlite3_free()] or [sqlite3_realloc()].
2272 */
2273 SQLITE_API void *sqlite3_malloc(int);
2274 SQLITE_API void *sqlite3_realloc(void*, int);
2275 SQLITE_API void sqlite3_free(void*);
2276
2277 /*
2278 ** CAPI3REF: Memory Allocator Statistics
2279 **
2280 ** SQLite provides these two interfaces for reporting on the status
2281 ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
2282 ** routines, which form the built-in memory allocation subsystem.
2283 **
2284 ** ^The [sqlite3_memory_used()] routine returns the number of bytes
2285 ** of memory currently outstanding (malloced but not freed).
2286 ** ^The [sqlite3_memory_highwater()] routine returns the maximum
2287 ** value of [sqlite3_memory_used()] since the high-water mark
2288 ** was last reset. ^The values returned by [sqlite3_memory_used()] and
2289 ** [sqlite3_memory_highwater()] include any overhead
2290 ** added by SQLite in its implementation of [sqlite3_malloc()],
2291 ** but not overhead added by the any underlying system library
2292 ** routines that [sqlite3_malloc()] may call.
2293 **
2294 ** ^The memory high-water mark is reset to the current value of
2295 ** [sqlite3_memory_used()] if and only if the parameter to
2296 ** [sqlite3_memory_highwater()] is true. ^The value returned
2297 ** by [sqlite3_memory_highwater(1)] is the high-water mark
2298 ** prior to the reset.
2299 */
2300 SQLITE_API sqlite3_int64 sqlite3_memory_used(void);
2301 SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
2302
2303 /*
2304 ** CAPI3REF: Pseudo-Random Number Generator
2305 **
2306 ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
2307 ** select random [ROWID | ROWIDs] when inserting new records into a table that
2308 ** already uses the largest possible [ROWID]. The PRNG is also used for
2309 ** the build-in random() and randomblob() SQL functions. This interface allows
2310 ** applications to access the same PRNG for other purposes.
2311 **
2312 ** ^A call to this routine stores N bytes of randomness into buffer P.
2313 **
2314 ** ^The first time this routine is invoked (either internally or by
2315 ** the application) the PRNG is seeded using randomness obtained
2316 ** from the xRandomness method of the default [sqlite3_vfs] object.
2317 ** ^On all subsequent invocations, the pseudo-randomness is generated
2318 ** internally and without recourse to the [sqlite3_vfs] xRandomness
2319 ** method.
2320 */
2321 SQLITE_API void sqlite3_randomness(int N, void *P);
2322
2323 /*
2324 ** CAPI3REF: Compile-Time Authorization Callbacks
2325 **
2326 ** ^This routine registers an authorizer callback with a particular
2327 ** [database connection], supplied in the first argument.
2328 ** ^The authorizer callback is invoked as SQL statements are being compiled
2329 ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
2330 ** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various
2331 ** points during the compilation process, as logic is being created
2332 ** to perform various actions, the authorizer callback is invoked to
2333 ** see if those actions are allowed. ^The authorizer callback should
2334 ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
2335 ** specific action but allow the SQL statement to continue to be
2336 ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
2337 ** rejected with an error. ^If the authorizer callback returns
2338 ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
2339 ** then the [sqlite3_prepare_v2()] or equivalent call that triggered
2340 ** the authorizer will fail with an error message.
2341 **
2342 ** When the callback returns [SQLITE_OK], that means the operation
2343 ** requested is ok. ^When the callback returns [SQLITE_DENY], the
2344 ** [sqlite3_prepare_v2()] or equivalent call that triggered the
2345 ** authorizer will fail with an error message explaining that
2346 ** access is denied.
2347 **
2348 ** ^The first parameter to the authorizer callback is a copy of the third
2349 ** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
2350 ** to the callback is an integer [SQLITE_COPY | action code] that specifies
2351 ** the particular action to be authorized. ^The third through sixth parameters
2352 ** to the callback are zero-terminated strings that contain additional
2353 ** details about the action to be authorized.
2354 **
2355 ** ^If the action code is [SQLITE_READ]
2356 ** and the callback returns [SQLITE_IGNORE] then the
2357 ** [prepared statement] statement is constructed to substitute
2358 ** a NULL value in place of the table column that would have
2359 ** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE]
2360 ** return can be used to deny an untrusted user access to individual
2361 ** columns of a table.
2362 ** ^If the action code is [SQLITE_DELETE] and the callback returns
2363 ** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
2364 ** [truncate optimization] is disabled and all rows are deleted individually.
2365 **
2366 ** An authorizer is used when [sqlite3_prepare | preparing]
2367 ** SQL statements from an untrusted source, to ensure that the SQL statements
2368 ** do not try to access data they are not allowed to see, or that they do not
2369 ** try to execute malicious statements that damage the database. For
2370 ** example, an application may allow a user to enter arbitrary
2371 ** SQL queries for evaluation by a database. But the application does
2372 ** not want the user to be able to make arbitrary changes to the
2373 ** database. An authorizer could then be put in place while the
2374 ** user-entered SQL is being [sqlite3_prepare | prepared] that
2375 ** disallows everything except [SELECT] statements.
2376 **
2377 ** Applications that need to process SQL from untrusted sources
2378 ** might also consider lowering resource limits using [sqlite3_limit()]
2379 ** and limiting database size using the [max_page_count] [PRAGMA]
2380 ** in addition to using an authorizer.
2381 **
2382 ** ^(Only a single authorizer can be in place on a database connection
2383 ** at a time. Each call to sqlite3_set_authorizer overrides the
2384 ** previous call.)^ ^Disable the authorizer by installing a NULL callback.
2385 ** The authorizer is disabled by default.
2386 **
2387 ** The authorizer callback must not do anything that will modify
2388 ** the database connection that invoked the authorizer callback.
2389 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2390 ** database connections for the meaning of "modify" in this paragraph.
2391 **
2392 ** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
2393 ** statement might be re-prepared during [sqlite3_step()] due to a
2394 ** schema change. Hence, the application should ensure that the
2395 ** correct authorizer callback remains in place during the [sqlite3_step()].
2396 **
2397 ** ^Note that the authorizer callback is invoked only during
2398 ** [sqlite3_prepare()] or its variants. Authorization is not
2399 ** performed during statement evaluation in [sqlite3_step()], unless
2400 ** as stated in the previous paragraph, sqlite3_step() invokes
2401 ** sqlite3_prepare_v2() to reprepare a statement after a schema change.
2402 */
2403 SQLITE_API int sqlite3_set_authorizer(
2404 sqlite3*,
2405 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
2406 void *pUserData
2407 );
2408
2409 /*
2410 ** CAPI3REF: Authorizer Return Codes
2411 **
2412 ** The [sqlite3_set_authorizer | authorizer callback function] must
2413 ** return either [SQLITE_OK] or one of these two constants in order
2414 ** to signal SQLite whether or not the action is permitted. See the
2415 ** [sqlite3_set_authorizer | authorizer documentation] for additional
2416 ** information.
2417 **
2418 ** Note that SQLITE_IGNORE is also used as a [SQLITE_ROLLBACK | return code]
2419 ** from the [sqlite3_vtab_on_conflict()] interface.
2420 */
2421 #define SQLITE_DENY 1 /* Abort the SQL statement with an error */
2422 #define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */
2423
2424 /*
2425 ** CAPI3REF: Authorizer Action Codes
2426 **
2427 ** The [sqlite3_set_authorizer()] interface registers a callback function
2428 ** that is invoked to authorize certain SQL statement actions. The
2429 ** second parameter to the callback is an integer code that specifies
2430 ** what action is being authorized. These are the integer action codes that
2431 ** the authorizer callback may be passed.
2432 **
2433 ** These action code values signify what kind of operation is to be
2434 ** authorized. The 3rd and 4th parameters to the authorization
2435 ** callback function will be parameters or NULL depending on which of these
2436 ** codes is used as the second parameter. ^(The 5th parameter to the
2437 ** authorizer callback is the name of the database ("main", "temp",
2438 ** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback
2439 ** is the name of the inner-most trigger or view that is responsible for
2440 ** the access attempt or NULL if this access attempt is directly from
2441 ** top-level SQL code.
2442 */
2443 /******************************************* 3rd ************ 4th ***********/
2444 #define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */
2445 #define SQLITE_CREATE_TABLE 2 /* Table Name NULL */
2446 #define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */
2447 #define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */
2448 #define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */
2449 #define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */
2450 #define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */
2451 #define SQLITE_CREATE_VIEW 8 /* View Name NULL */
2452 #define SQLITE_DELETE 9 /* Table Name NULL */
2453 #define SQLITE_DROP_INDEX 10 /* Index Name Table Name */
2454 #define SQLITE_DROP_TABLE 11 /* Table Name NULL */
2455 #define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */
2456 #define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */
2457 #define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */
2458 #define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */
2459 #define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */
2460 #define SQLITE_DROP_VIEW 17 /* View Name NULL */
2461 #define SQLITE_INSERT 18 /* Table Name NULL */
2462 #define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */
2463 #define SQLITE_READ 20 /* Table Name Column Name */
2464 #define SQLITE_SELECT 21 /* NULL NULL */
2465 #define SQLITE_TRANSACTION 22 /* Operation NULL */
2466 #define SQLITE_UPDATE 23 /* Table Name Column Name */
2467 #define SQLITE_ATTACH 24 /* Filename NULL */
2468 #define SQLITE_DETACH 25 /* Database Name NULL */
2469 #define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */
2470 #define SQLITE_REINDEX 27 /* Index Name NULL */
2471 #define SQLITE_ANALYZE 28 /* Table Name NULL */
2472 #define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */
2473 #define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */
2474 #define SQLITE_FUNCTION 31 /* NULL Function Name */
2475 #define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */
2476 #define SQLITE_COPY 0 /* No longer used */
2477
2478 /*
2479 ** CAPI3REF: Tracing And Profiling Functions
2480 **
2481 ** These routines register callback functions that can be used for
2482 ** tracing and profiling the execution of SQL statements.
2483 **
2484 ** ^The callback function registered by sqlite3_trace() is invoked at
2485 ** various times when an SQL statement is being run by [sqlite3_step()].
2486 ** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
2487 ** SQL statement text as the statement first begins executing.
2488 ** ^(Additional sqlite3_trace() callbacks might occur
2489 ** as each triggered subprogram is entered. The callbacks for triggers
2490 ** contain a UTF-8 SQL comment that identifies the trigger.)^
2491 **
2492 ** ^The callback function registered by sqlite3_profile() is invoked
2493 ** as each SQL statement finishes. ^The profile callback contains
2494 ** the original statement text and an estimate of wall-clock time
2495 ** of how long that statement took to run. ^The profile callback
2496 ** time is in units of nanoseconds, however the current implementation
2497 ** is only capable of millisecond resolution so the six least significant
2498 ** digits in the time are meaningless. Future versions of SQLite
2499 ** might provide greater resolution on the profiler callback. The
2500 ** sqlite3_profile() function is considered experimental and is
2501 ** subject to change in future versions of SQLite.
2502 */
2503 SQLITE_API void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*);
2504 SQLITE_API SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*,
2505 void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
2506
2507 /*
2508 ** CAPI3REF: Query Progress Callbacks
2509 **
2510 ** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
2511 ** function X to be invoked periodically during long running calls to
2512 ** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for
2513 ** database connection D. An example use for this
2514 ** interface is to keep a GUI updated during a large query.
2515 **
2516 ** ^The parameter P is passed through as the only parameter to the
2517 ** callback function X. ^The parameter N is the number of
2518 ** [virtual machine instructions] that are evaluated between successive
2519 ** invocations of the callback X.
2520 **
2521 ** ^Only a single progress handler may be defined at one time per
2522 ** [database connection]; setting a new progress handler cancels the
2523 ** old one. ^Setting parameter X to NULL disables the progress handler.
2524 ** ^The progress handler is also disabled by setting N to a value less
2525 ** than 1.
2526 **
2527 ** ^If the progress callback returns non-zero, the operation is
2528 ** interrupted. This feature can be used to implement a
2529 ** "Cancel" button on a GUI progress dialog box.
2530 **
2531 ** The progress handler callback must not do anything that will modify
2532 ** the database connection that invoked the progress handler.
2533 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2534 ** database connections for the meaning of "modify" in this paragraph.
2535 **
2536 */
2537 SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
2538
2539 /*
2540 ** CAPI3REF: Opening A New Database Connection
2541 **
2542 ** ^These routines open an SQLite database file as specified by the
2543 ** filename argument. ^The filename argument is interpreted as UTF-8 for
2544 ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
2545 ** order for sqlite3_open16(). ^(A [database connection] handle is usually
2546 ** returned in *ppDb, even if an error occurs. The only exception is that
2547 ** if SQLite is unable to allocate memory to hold the [sqlite3] object,
2548 ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
2549 ** object.)^ ^(If the database is opened (and/or created) successfully, then
2550 ** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The
2551 ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
2552 ** an English language description of the error following a failure of any
2553 ** of the sqlite3_open() routines.
2554 **
2555 ** ^The default encoding for the database will be UTF-8 if
2556 ** sqlite3_open() or sqlite3_open_v2() is called and
2557 ** UTF-16 in the native byte order if sqlite3_open16() is used.
2558 **
2559 ** Whether or not an error occurs when it is opened, resources
2560 ** associated with the [database connection] handle should be released by
2561 ** passing it to [sqlite3_close()] when it is no longer required.
2562 **
2563 ** The sqlite3_open_v2() interface works like sqlite3_open()
2564 ** except that it accepts two additional parameters for additional control
2565 ** over the new database connection. ^(The flags parameter to
2566 ** sqlite3_open_v2() can take one of
2567 ** the following three values, optionally combined with the
2568 ** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE],
2569 ** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^
2570 **
2571 ** <dl>
2572 ** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
2573 ** <dd>The database is opened in read-only mode. If the database does not
2574 ** already exist, an error is returned.</dd>)^
2575 **
2576 ** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
2577 ** <dd>The database is opened for reading and writing if possible, or reading
2578 ** only if the file is write protected by the operating system. In either
2579 ** case the database must already exist, otherwise an error is returned.</dd>)^
2580 **
2581 ** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
2582 ** <dd>The database is opened for reading and writing, and is created if
2583 ** it does not already exist. This is the behavior that is always used for
2584 ** sqlite3_open() and sqlite3_open16().</dd>)^
2585 ** </dl>
2586 **
2587 ** If the 3rd parameter to sqlite3_open_v2() is not one of the
2588 ** combinations shown above optionally combined with other
2589 ** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits]
2590 ** then the behavior is undefined.
2591 **
2592 ** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection
2593 ** opens in the multi-thread [threading mode] as long as the single-thread
2594 ** mode has not been set at compile-time or start-time. ^If the
2595 ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens
2596 ** in the serialized [threading mode] unless single-thread was
2597 ** previously selected at compile-time or start-time.
2598 ** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be
2599 ** eligible to use [shared cache mode], regardless of whether or not shared
2600 ** cache is enabled using [sqlite3_enable_shared_cache()]. ^The
2601 ** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not
2602 ** participate in [shared cache mode] even if it is enabled.
2603 **
2604 ** ^The fourth parameter to sqlite3_open_v2() is the name of the
2605 ** [sqlite3_vfs] object that defines the operating system interface that
2606 ** the new database connection should use. ^If the fourth parameter is
2607 ** a NULL pointer then the default [sqlite3_vfs] object is used.
2608 **
2609 ** ^If the filename is ":memory:", then a private, temporary in-memory database
2610 ** is created for the connection. ^This in-memory database will vanish when
2611 ** the database connection is closed. Future versions of SQLite might
2612 ** make use of additional special filenames that begin with the ":" character.
2613 ** It is recommended that when a database filename actually does begin with
2614 ** a ":" character you should prefix the filename with a pathname such as
2615 ** "./" to avoid ambiguity.
2616 **
2617 ** ^If the filename is an empty string, then a private, temporary
2618 ** on-disk database will be created. ^This private database will be
2619 ** automatically deleted as soon as the database connection is closed.
2620 **
2621 ** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
2622 **
2623 ** ^If [URI filename] interpretation is enabled, and the filename argument
2624 ** begins with "file:", then the filename is interpreted as a URI. ^URI
2625 ** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
2626 ** set in the fourth argument to sqlite3_open_v2(), or if it has
2627 ** been enabled globally using the [SQLITE_CONFIG_URI] option with the
2628 ** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
2629 ** As of SQLite version 3.7.7, URI filename interpretation is turned off
2630 ** by default, but future releases of SQLite might enable URI filename
2631 ** interpretation by default. See "[URI filenames]" for additional
2632 ** information.
2633 **
2634 ** URI filenames are parsed according to RFC 3986. ^If the URI contains an
2635 ** authority, then it must be either an empty string or the string
2636 ** "localhost". ^If the authority is not an empty string or "localhost", an
2637 ** error is returned to the caller. ^The fragment component of a URI, if
2638 ** present, is ignored.
2639 **
2640 ** ^SQLite uses the path component of the URI as the name of the disk file
2641 ** which contains the database. ^If the path begins with a '/' character,
2642 ** then it is interpreted as an absolute path. ^If the path does not begin
2643 ** with a '/' (meaning that the authority section is omitted from the URI)
2644 ** then the path is interpreted as a relative path.
2645 ** ^On windows, the first component of an absolute path
2646 ** is a drive specification (e.g. "C:").
2647 **
2648 ** [[core URI query parameters]]
2649 ** The query component of a URI may contain parameters that are interpreted
2650 ** either by SQLite itself, or by a [VFS | custom VFS implementation].
2651 ** SQLite interprets the following three query parameters:
2652 **
2653 ** <ul>
2654 ** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
2655 ** a VFS object that provides the operating system interface that should
2656 ** be used to access the database file on disk. ^If this option is set to
2657 ** an empty string the default VFS object is used. ^Specifying an unknown
2658 ** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
2659 ** present, then the VFS specified by the option takes precedence over
2660 ** the value passed as the fourth parameter to sqlite3_open_v2().
2661 **
2662 ** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw",
2663 ** "rwc", or "memory". Attempting to set it to any other value is
2664 ** an error)^.
2665 ** ^If "ro" is specified, then the database is opened for read-only
2666 ** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the
2667 ** third argument to sqlite3_open_v2(). ^If the mode option is set to
2668 ** "rw", then the database is opened for read-write (but not create)
2669 ** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had
2670 ** been set. ^Value "rwc" is equivalent to setting both
2671 ** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is
2672 ** set to "memory" then a pure [in-memory database] that never reads
2673 ** or writes from disk is used. ^It is an error to specify a value for
2674 ** the mode parameter that is less restrictive than that specified by
2675 ** the flags passed in the third parameter to sqlite3_open_v2().
2676 **
2677 ** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
2678 ** "private". ^Setting it to "shared" is equivalent to setting the
2679 ** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
2680 ** sqlite3_open_v2(). ^Setting the cache parameter to "private" is
2681 ** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
2682 ** ^If sqlite3_open_v2() is used and the "cache" parameter is present in
2683 ** a URI filename, its value overrides any behaviour requested by setting
2684 ** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.
2685 ** </ul>
2686 **
2687 ** ^Specifying an unknown parameter in the query component of a URI is not an
2688 ** error. Future versions of SQLite might understand additional query
2689 ** parameters. See "[query parameters with special meaning to SQLite]" for
2690 ** additional information.
2691 **
2692 ** [[URI filename examples]] <h3>URI filename examples</h3>
2693 **
2694 ** <table border="1" align=center cellpadding=5>
2695 ** <tr><th> URI filenames <th> Results
2696 ** <tr><td> file:data.db <td>
2697 ** Open the file "data.db" in the current directory.
2698 ** <tr><td> file:/home/fred/data.db<br>
2699 ** file:///home/fred/data.db <br>
2700 ** file://localhost/home/fred/data.db <br> <td>
2701 ** Open the database file "/home/fred/data.db".
2702 ** <tr><td> file://darkstar/home/fred/data.db <td>
2703 ** An error. "darkstar" is not a recognized authority.
2704 ** <tr><td style="white-space:nowrap">
2705 ** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
2706 ** <td> Windows only: Open the file "data.db" on fred's desktop on drive
2707 ** C:. Note that the %20 escaping in this example is not strictly
2708 ** necessary - space characters can be used literally
2709 ** in URI filenames.
2710 ** <tr><td> file:data.db?mode=ro&cache=private <td>
2711 ** Open file "data.db" in the current directory for read-only access.
2712 ** Regardless of whether or not shared-cache mode is enabled by
2713 ** default, use a private cache.
2714 ** <tr><td> file:/home/fred/data.db?vfs=unix-nolock <td>
2715 ** Open file "/home/fred/data.db". Use the special VFS "unix-nolock".
2716 ** <tr><td> file:data.db?mode=readonly <td>
2717 ** An error. "readonly" is not a valid option for the "mode" parameter.
2718 ** </table>
2719 **
2720 ** ^URI hexadecimal escape sequences (%HH) are supported within the path and
2721 ** query components of a URI. A hexadecimal escape sequence consists of a
2722 ** percent sign - "%" - followed by exactly two hexadecimal digits
2723 ** specifying an octet value. ^Before the path or query components of a
2724 ** URI filename are interpreted, they are encoded using UTF-8 and all
2725 ** hexadecimal escape sequences replaced by a single byte containing the
2726 ** corresponding octet. If this process generates an invalid UTF-8 encoding,
2727 ** the results are undefined.
2728 **
2729 ** <b>Note to Windows users:</b> The encoding used for the filename argument
2730 ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
2731 ** codepage is currently defined. Filenames containing international
2732 ** characters must be converted to UTF-8 prior to passing them into
2733 ** sqlite3_open() or sqlite3_open_v2().
2734 **
2735 ** <b>Note to Windows Runtime users:</b> The temporary directory must be set
2736 ** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various
2737 ** features that require the use of temporary files may fail.
2738 **
2739 ** See also: [sqlite3_temp_directory]
2740 */
2741 SQLITE_API int sqlite3_open(
2742 const char *filename, /* Database filename (UTF-8) */
2743 sqlite3 **ppDb /* OUT: SQLite db handle */
2744 );
2745 SQLITE_API int sqlite3_open16(
2746 const void *filename, /* Database filename (UTF-16) */
2747 sqlite3 **ppDb /* OUT: SQLite db handle */
2748 );
2749 SQLITE_API int sqlite3_open_v2(
2750 const char *filename, /* Database filename (UTF-8) */
2751 sqlite3 **ppDb, /* OUT: SQLite db handle */
2752 int flags, /* Flags */
2753 const char *zVfs /* Name of VFS module to use */
2754 );
2755
2756 /*
2757 ** CAPI3REF: Obtain Values For URI Parameters
2758 **
2759 ** These are utility routines, useful to VFS implementations, that check
2760 ** to see if a database file was a URI that contained a specific query
2761 ** parameter, and if so obtains the value of that query parameter.
2762 **
2763 ** If F is the database filename pointer passed into the xOpen() method of
2764 ** a VFS implementation when the flags parameter to xOpen() has one or
2765 ** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and
2766 ** P is the name of the query parameter, then
2767 ** sqlite3_uri_parameter(F,P) returns the value of the P
2768 ** parameter if it exists or a NULL pointer if P does not appear as a
2769 ** query parameter on F. If P is a query parameter of F
2770 ** has no explicit value, then sqlite3_uri_parameter(F,P) returns
2771 ** a pointer to an empty string.
2772 **
2773 ** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
2774 ** parameter and returns true (1) or false (0) according to the value
2775 ** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
2776 ** value of query parameter P is one of "yes", "true", or "on" in any
2777 ** case or if the value begins with a non-zero number. The
2778 ** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
2779 ** query parameter P is one of "no", "false", or "off" in any case or
2780 ** if the value begins with a numeric zero. If P is not a query
2781 ** parameter on F or if the value of P is does not match any of the
2782 ** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).
2783 **
2784 ** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
2785 ** 64-bit signed integer and returns that integer, or D if P does not
2786 ** exist. If the value of P is something other than an integer, then
2787 ** zero is returned.
2788 **
2789 ** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
2790 ** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and
2791 ** is not a database file pathname pointer that SQLite passed into the xOpen
2792 ** VFS method, then the behavior of this routine is undefined and probably
2793 ** undesirable.
2794 */
2795 SQLITE_API const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam);
2796 SQLITE_API int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault);
2797 SQLITE_API sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64);
2798
2799
2800 /*
2801 ** CAPI3REF: Error Codes And Messages
2802 **
2803 ** ^The sqlite3_errcode() interface returns the numeric [result code] or
2804 ** [extended result code] for the most recent failed sqlite3_* API call
2805 ** associated with a [database connection]. If a prior API call failed
2806 ** but the most recent API call succeeded, the return value from
2807 ** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode()
2808 ** interface is the same except that it always returns the
2809 ** [extended result code] even when extended result codes are
2810 ** disabled.
2811 **
2812 ** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
2813 ** text that describes the error, as either UTF-8 or UTF-16 respectively.
2814 ** ^(Memory to hold the error message string is managed internally.
2815 ** The application does not need to worry about freeing the result.
2816 ** However, the error string might be overwritten or deallocated by
2817 ** subsequent calls to other SQLite interface functions.)^
2818 **
2819 ** ^The sqlite3_errstr() interface returns the English-language text
2820 ** that describes the [result code], as UTF-8.
2821 ** ^(Memory to hold the error message string is managed internally
2822 ** and must not be freed by the application)^.
2823 **
2824 ** When the serialized [threading mode] is in use, it might be the
2825 ** case that a second error occurs on a separate thread in between
2826 ** the time of the first error and the call to these interfaces.
2827 ** When that happens, the second error will be reported since these
2828 ** interfaces always report the most recent result. To avoid
2829 ** this, each thread can obtain exclusive use of the [database connection] D
2830 ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
2831 ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
2832 ** all calls to the interfaces listed here are completed.
2833 **
2834 ** If an interface fails with SQLITE_MISUSE, that means the interface
2835 ** was invoked incorrectly by the application. In that case, the
2836 ** error code and message may or may not be set.
2837 */
2838 SQLITE_API int sqlite3_errcode(sqlite3 *db);
2839 SQLITE_API int sqlite3_extended_errcode(sqlite3 *db);
2840 SQLITE_API const char *sqlite3_errmsg(sqlite3*);
2841 SQLITE_API const void *sqlite3_errmsg16(sqlite3*);
2842 SQLITE_API const char *sqlite3_errstr(int);
2843
2844 /*
2845 ** CAPI3REF: SQL Statement Object
2846 ** KEYWORDS: {prepared statement} {prepared statements}
2847 **
2848 ** An instance of this object represents a single SQL statement.
2849 ** This object is variously known as a "prepared statement" or a
2850 ** "compiled SQL statement" or simply as a "statement".
2851 **
2852 ** The life of a statement object goes something like this:
2853 **
2854 ** <ol>
2855 ** <li> Create the object using [sqlite3_prepare_v2()] or a related
2856 ** function.
2857 ** <li> Bind values to [host parameters] using the sqlite3_bind_*()
2858 ** interfaces.
2859 ** <li> Run the SQL by calling [sqlite3_step()] one or more times.
2860 ** <li> Reset the statement using [sqlite3_reset()] then go back
2861 ** to step 2. Do this zero or more times.
2862 ** <li> Destroy the object using [sqlite3_finalize()].
2863 ** </ol>
2864 **
2865 ** Refer to documentation on individual methods above for additional
2866 ** information.
2867 */
2868 typedef struct sqlite3_stmt sqlite3_stmt;
2869
2870 /*
2871 ** CAPI3REF: Run-time Limits
2872 **
2873 ** ^(This interface allows the size of various constructs to be limited
2874 ** on a connection by connection basis. The first parameter is the
2875 ** [database connection] whose limit is to be set or queried. The
2876 ** second parameter is one of the [limit categories] that define a
2877 ** class of constructs to be size limited. The third parameter is the
2878 ** new limit for that construct.)^
2879 **
2880 ** ^If the new limit is a negative number, the limit is unchanged.
2881 ** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
2882 ** [limits | hard upper bound]
2883 ** set at compile-time by a C preprocessor macro called
2884 ** [limits | SQLITE_MAX_<i>NAME</i>].
2885 ** (The "_LIMIT_" in the name is changed to "_MAX_".))^
2886 ** ^Attempts to increase a limit above its hard upper bound are
2887 ** silently truncated to the hard upper bound.
2888 **
2889 ** ^Regardless of whether or not the limit was changed, the
2890 ** [sqlite3_limit()] interface returns the prior value of the limit.
2891 ** ^Hence, to find the current value of a limit without changing it,
2892 ** simply invoke this interface with the third parameter set to -1.
2893 **
2894 ** Run-time limits are intended for use in applications that manage
2895 ** both their own internal database and also databases that are controlled
2896 ** by untrusted external sources. An example application might be a
2897 ** web browser that has its own databases for storing history and
2898 ** separate databases controlled by JavaScript applications downloaded
2899 ** off the Internet. The internal databases can be given the
2900 ** large, default limits. Databases managed by external sources can
2901 ** be given much smaller limits designed to prevent a denial of service
2902 ** attack. Developers might also want to use the [sqlite3_set_authorizer()]
2903 ** interface to further control untrusted SQL. The size of the database
2904 ** created by an untrusted script can be contained using the
2905 ** [max_page_count] [PRAGMA].
2906 **
2907 ** New run-time limit categories may be added in future releases.
2908 */
2909 SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal);
2910
2911 /*
2912 ** CAPI3REF: Run-Time Limit Categories
2913 ** KEYWORDS: {limit category} {*limit categories}
2914 **
2915 ** These constants define various performance limits
2916 ** that can be lowered at run-time using [sqlite3_limit()].
2917 ** The synopsis of the meanings of the various limits is shown below.
2918 ** Additional information is available at [limits | Limits in SQLite].
2919 **
2920 ** <dl>
2921 ** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt>
2922 ** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
2923 **
2924 ** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
2925 ** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
2926 **
2927 ** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt>
2928 ** <dd>The maximum number of columns in a table definition or in the
2929 ** result set of a [SELECT] or the maximum number of columns in an index
2930 ** or in an ORDER BY or GROUP BY clause.</dd>)^
2931 **
2932 ** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
2933 ** <dd>The maximum depth of the parse tree on any expression.</dd>)^
2934 **
2935 ** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
2936 ** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
2937 **
2938 ** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
2939 ** <dd>The maximum number of instructions in a virtual machine program
2940 ** used to implement an SQL statement. This limit is not currently
2941 ** enforced, though that might be added in some future release of
2942 ** SQLite.</dd>)^
2943 **
2944 ** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
2945 ** <dd>The maximum number of arguments on a function.</dd>)^
2946 **
2947 ** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
2948 ** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
2949 **
2950 ** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]]
2951 ** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
2952 ** <dd>The maximum length of the pattern argument to the [LIKE] or
2953 ** [GLOB] operators.</dd>)^
2954 **
2955 ** [[SQLITE_LIMIT_VARIABLE_NUMBER]]
2956 ** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
2957 ** <dd>The maximum index number of any [parameter] in an SQL statement.)^
2958 **
2959 ** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
2960 ** <dd>The maximum depth of recursion for triggers.</dd>)^
2961 ** </dl>
2962 */
2963 #define SQLITE_LIMIT_LENGTH 0
2964 #define SQLITE_LIMIT_SQL_LENGTH 1
2965 #define SQLITE_LIMIT_COLUMN 2
2966 #define SQLITE_LIMIT_EXPR_DEPTH 3
2967 #define SQLITE_LIMIT_COMPOUND_SELECT 4
2968 #define SQLITE_LIMIT_VDBE_OP 5
2969 #define SQLITE_LIMIT_FUNCTION_ARG 6
2970 #define SQLITE_LIMIT_ATTACHED 7
2971 #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8
2972 #define SQLITE_LIMIT_VARIABLE_NUMBER 9
2973 #define SQLITE_LIMIT_TRIGGER_DEPTH 10
2974
2975 /*
2976 ** CAPI3REF: Compiling An SQL Statement
2977 ** KEYWORDS: {SQL statement compiler}
2978 **
2979 ** To execute an SQL query, it must first be compiled into a byte-code
2980 ** program using one of these routines.
2981 **
2982 ** The first argument, "db", is a [database connection] obtained from a
2983 ** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
2984 ** [sqlite3_open16()]. The database connection must not have been closed.
2985 **
2986 ** The second argument, "zSql", is the statement to be compiled, encoded
2987 ** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2()
2988 ** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2()
2989 ** use UTF-16.
2990 **
2991 ** ^If the nByte argument is less than zero, then zSql is read up to the
2992 ** first zero terminator. ^If nByte is non-negative, then it is the maximum
2993 ** number of bytes read from zSql. ^When nByte is non-negative, the
2994 ** zSql string ends at either the first '\000' or '\u0000' character or
2995 ** the nByte-th byte, whichever comes first. If the caller knows
2996 ** that the supplied string is nul-terminated, then there is a small
2997 ** performance advantage to be gained by passing an nByte parameter that
2998 ** is equal to the number of bytes in the input string <i>including</i>
2999 ** the nul-terminator bytes as this saves SQLite from having to
3000 ** make a copy of the input string.
3001 **
3002 ** ^If pzTail is not NULL then *pzTail is made to point to the first byte
3003 ** past the end of the first SQL statement in zSql. These routines only
3004 ** compile the first statement in zSql, so *pzTail is left pointing to
3005 ** what remains uncompiled.
3006 **
3007 ** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
3008 ** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set
3009 ** to NULL. ^If the input text contains no SQL (if the input is an empty
3010 ** string or a comment) then *ppStmt is set to NULL.
3011 ** The calling procedure is responsible for deleting the compiled
3012 ** SQL statement using [sqlite3_finalize()] after it has finished with it.
3013 ** ppStmt may not be NULL.
3014 **
3015 ** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
3016 ** otherwise an [error code] is returned.
3017 **
3018 ** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are
3019 ** recommended for all new programs. The two older interfaces are retained
3020 ** for backwards compatibility, but their use is discouraged.
3021 ** ^In the "v2" interfaces, the prepared statement
3022 ** that is returned (the [sqlite3_stmt] object) contains a copy of the
3023 ** original SQL text. This causes the [sqlite3_step()] interface to
3024 ** behave differently in three ways:
3025 **
3026 ** <ol>
3027 ** <li>
3028 ** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
3029 ** always used to do, [sqlite3_step()] will automatically recompile the SQL
3030 ** statement and try to run it again.
3031 ** </li>
3032 **
3033 ** <li>
3034 ** ^When an error occurs, [sqlite3_step()] will return one of the detailed
3035 ** [error codes] or [extended error codes]. ^The legacy behavior was that
3036 ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
3037 ** and the application would have to make a second call to [sqlite3_reset()]
3038 ** in order to find the underlying cause of the problem. With the "v2" prepare
3039 ** interfaces, the underlying reason for the error is returned immediately.
3040 ** </li>
3041 **
3042 ** <li>
3043 ** ^If the specific value bound to [parameter | host parameter] in the
3044 ** WHERE clause might influence the choice of query plan for a statement,
3045 ** then the statement will be automatically recompiled, as if there had been
3046 ** a schema change, on the first [sqlite3_step()] call following any change
3047 ** to the [sqlite3_bind_text | bindings] of that [parameter].
3048 ** ^The specific value of WHERE-clause [parameter] might influence the
3049 ** choice of query plan if the parameter is the left-hand side of a [LIKE]
3050 ** or [GLOB] operator or if the parameter is compared to an indexed column
3051 ** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled.
3052 ** the
3053 ** </li>
3054 ** </ol>
3055 */
3056 SQLITE_API int sqlite3_prepare(
3057 sqlite3 *db, /* Database handle */
3058 const char *zSql, /* SQL statement, UTF-8 encoded */
3059 int nByte, /* Maximum length of zSql in bytes. */
3060 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3061 const char **pzTail /* OUT: Pointer to unused portion of zSql */
3062 );
3063 SQLITE_API int sqlite3_prepare_v2(
3064 sqlite3 *db, /* Database handle */
3065 const char *zSql, /* SQL statement, UTF-8 encoded */
3066 int nByte, /* Maximum length of zSql in bytes. */
3067 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3068 const char **pzTail /* OUT: Pointer to unused portion of zSql */
3069 );
3070 SQLITE_API int sqlite3_prepare16(
3071 sqlite3 *db, /* Database handle */
3072 const void *zSql, /* SQL statement, UTF-16 encoded */
3073 int nByte, /* Maximum length of zSql in bytes. */
3074 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3075 const void **pzTail /* OUT: Pointer to unused portion of zSql */
3076 );
3077 SQLITE_API int sqlite3_prepare16_v2(
3078 sqlite3 *db, /* Database handle */
3079 const void *zSql, /* SQL statement, UTF-16 encoded */
3080 int nByte, /* Maximum length of zSql in bytes. */
3081 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3082 const void **pzTail /* OUT: Pointer to unused portion of zSql */
3083 );
3084
3085 /*
3086 ** CAPI3REF: Retrieving Statement SQL
3087 **
3088 ** ^This interface can be used to retrieve a saved copy of the original
3089 ** SQL text used to create a [prepared statement] if that statement was
3090 ** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()].
3091 */
3092 SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt);
3093
3094 /*
3095 ** CAPI3REF: Determine If An SQL Statement Writes The Database
3096 **
3097 ** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
3098 ** and only if the [prepared statement] X makes no direct changes to
3099 ** the content of the database file.
3100 **
3101 ** Note that [application-defined SQL functions] or
3102 ** [virtual tables] might change the database indirectly as a side effect.
3103 ** ^(For example, if an application defines a function "eval()" that
3104 ** calls [sqlite3_exec()], then the following SQL statement would
3105 ** change the database file through side-effects:
3106 **
3107 ** <blockquote><pre>
3108 ** SELECT eval('DELETE FROM t1') FROM t2;
3109 ** </pre></blockquote>
3110 **
3111 ** But because the [SELECT] statement does not change the database file
3112 ** directly, sqlite3_stmt_readonly() would still return true.)^
3113 **
3114 ** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
3115 ** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
3116 ** since the statements themselves do not actually modify the database but
3117 ** rather they control the timing of when other statements modify the
3118 ** database. ^The [ATTACH] and [DETACH] statements also cause
3119 ** sqlite3_stmt_readonly() to return true since, while those statements
3120 ** change the configuration of a database connection, they do not make
3121 ** changes to the content of the database files on disk.
3122 */
3123 SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
3124
3125 /*
3126 ** CAPI3REF: Determine If A Prepared Statement Has Been Reset
3127 **
3128 ** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
3129 ** [prepared statement] S has been stepped at least once using
3130 ** [sqlite3_step(S)] but has not run to completion and/or has not
3131 ** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S)
3132 ** interface returns false if S is a NULL pointer. If S is not a
3133 ** NULL pointer and is not a pointer to a valid [prepared statement]
3134 ** object, then the behavior is undefined and probably undesirable.
3135 **
3136 ** This interface can be used in combination [sqlite3_next_stmt()]
3137 ** to locate all prepared statements associated with a database
3138 ** connection that are in need of being reset. This can be used,
3139 ** for example, in diagnostic routines to search for prepared
3140 ** statements that are holding a transaction open.
3141 */
3142 SQLITE_API int sqlite3_stmt_busy(sqlite3_stmt*);
3143
3144 /*
3145 ** CAPI3REF: Dynamically Typed Value Object
3146 ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
3147 **
3148 ** SQLite uses the sqlite3_value object to represent all values
3149 ** that can be stored in a database table. SQLite uses dynamic typing
3150 ** for the values it stores. ^Values stored in sqlite3_value objects
3151 ** can be integers, floating point values, strings, BLOBs, or NULL.
3152 **
3153 ** An sqlite3_value object may be either "protected" or "unprotected".
3154 ** Some interfaces require a protected sqlite3_value. Other interfaces
3155 ** will accept either a protected or an unprotected sqlite3_value.
3156 ** Every interface that accepts sqlite3_value arguments specifies
3157 ** whether or not it requires a protected sqlite3_value.
3158 **
3159 ** The terms "protected" and "unprotected" refer to whether or not
3160 ** a mutex is held. An internal mutex is held for a protected
3161 ** sqlite3_value object but no mutex is held for an unprotected
3162 ** sqlite3_value object. If SQLite is compiled to be single-threaded
3163 ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
3164 ** or if SQLite is run in one of reduced mutex modes
3165 ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
3166 ** then there is no distinction between protected and unprotected
3167 ** sqlite3_value objects and they can be used interchangeably. However,
3168 ** for maximum code portability it is recommended that applications
3169 ** still make the distinction between protected and unprotected
3170 ** sqlite3_value objects even when not strictly required.
3171 **
3172 ** ^The sqlite3_value objects that are passed as parameters into the
3173 ** implementation of [application-defined SQL functions] are protected.
3174 ** ^The sqlite3_value object returned by
3175 ** [sqlite3_column_value()] is unprotected.
3176 ** Unprotected sqlite3_value objects may only be used with
3177 ** [sqlite3_result_value()] and [sqlite3_bind_value()].
3178 ** The [sqlite3_value_blob | sqlite3_value_type()] family of
3179 ** interfaces require protected sqlite3_value objects.
3180 */
3181 typedef struct Mem sqlite3_value;
3182
3183 /*
3184 ** CAPI3REF: SQL Function Context Object
3185 **
3186 ** The context in which an SQL function executes is stored in an
3187 ** sqlite3_context object. ^A pointer to an sqlite3_context object
3188 ** is always first parameter to [application-defined SQL functions].
3189 ** The application-defined SQL function implementation will pass this
3190 ** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
3191 ** [sqlite3_aggregate_context()], [sqlite3_user_data()],
3192 ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
3193 ** and/or [sqlite3_set_auxdata()].
3194 */
3195 typedef struct sqlite3_context sqlite3_context;
3196
3197 /*
3198 ** CAPI3REF: Binding Values To Prepared Statements
3199 ** KEYWORDS: {host parameter} {host parameters} {host parameter name}
3200 ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
3201 **
3202 ** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
3203 ** literals may be replaced by a [parameter] that matches one of following
3204 ** templates:
3205 **
3206 ** <ul>
3207 ** <li> ?
3208 ** <li> ?NNN
3209 ** <li> :VVV
3210 ** <li> @VVV
3211 ** <li> $VVV
3212 ** </ul>
3213 **
3214 ** In the templates above, NNN represents an integer literal,
3215 ** and VVV represents an alphanumeric identifier.)^ ^The values of these
3216 ** parameters (also called "host parameter names" or "SQL parameters")
3217 ** can be set using the sqlite3_bind_*() routines defined here.
3218 **
3219 ** ^The first argument to the sqlite3_bind_*() routines is always
3220 ** a pointer to the [sqlite3_stmt] object returned from
3221 ** [sqlite3_prepare_v2()] or its variants.
3222 **
3223 ** ^The second argument is the index of the SQL parameter to be set.
3224 ** ^The leftmost SQL parameter has an index of 1. ^When the same named
3225 ** SQL parameter is used more than once, second and subsequent
3226 ** occurrences have the same index as the first occurrence.
3227 ** ^The index for named parameters can be looked up using the
3228 ** [sqlite3_bind_parameter_index()] API if desired. ^The index
3229 ** for "?NNN" parameters is the value of NNN.
3230 ** ^The NNN value must be between 1 and the [sqlite3_limit()]
3231 ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999).
3232 **
3233 ** ^The third argument is the value to bind to the parameter.
3234 **
3235 ** ^(In those routines that have a fourth argument, its value is the
3236 ** number of bytes in the parameter. To be clear: the value is the
3237 ** number of <u>bytes</u> in the value, not the number of characters.)^
3238 ** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()
3239 ** is negative, then the length of the string is
3240 ** the number of bytes up to the first zero terminator.
3241 ** If the fourth parameter to sqlite3_bind_blob() is negative, then
3242 ** the behavior is undefined.
3243 ** If a non-negative fourth parameter is provided to sqlite3_bind_text()
3244 ** or sqlite3_bind_text16() then that parameter must be the byte offset
3245 ** where the NUL terminator would occur assuming the string were NUL
3246 ** terminated. If any NUL characters occur at byte offsets less than
3247 ** the value of the fourth parameter then the resulting string value will
3248 ** contain embedded NULs. The result of expressions involving strings
3249 ** with embedded NULs is undefined.
3250 **
3251 ** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and
3252 ** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or
3253 ** string after SQLite has finished with it. ^The destructor is called
3254 ** to dispose of the BLOB or string even if the call to sqlite3_bind_blob(),
3255 ** sqlite3_bind_text(), or sqlite3_bind_text16() fails.
3256 ** ^If the fifth argument is
3257 ** the special value [SQLITE_STATIC], then SQLite assumes that the
3258 ** information is in static, unmanaged space and does not need to be freed.
3259 ** ^If the fifth argument has the value [SQLITE_TRANSIENT], then
3260 ** SQLite makes its own private copy of the data immediately, before
3261 ** the sqlite3_bind_*() routine returns.
3262 **
3263 ** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
3264 ** is filled with zeroes. ^A zeroblob uses a fixed amount of memory
3265 ** (just an integer to hold its size) while it is being processed.
3266 ** Zeroblobs are intended to serve as placeholders for BLOBs whose
3267 ** content is later written using
3268 ** [sqlite3_blob_open | incremental BLOB I/O] routines.
3269 ** ^A negative value for the zeroblob results in a zero-length BLOB.
3270 **
3271 ** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
3272 ** for the [prepared statement] or with a prepared statement for which
3273 ** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
3274 ** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_()
3275 ** routine is passed a [prepared statement] that has been finalized, the
3276 ** result is undefined and probably harmful.
3277 **
3278 ** ^Bindings are not cleared by the [sqlite3_reset()] routine.
3279 ** ^Unbound parameters are interpreted as NULL.
3280 **
3281 ** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
3282 ** [error code] if anything goes wrong.
3283 ** ^[SQLITE_RANGE] is returned if the parameter
3284 ** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails.
3285 **
3286 ** See also: [sqlite3_bind_parameter_count()],
3287 ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
3288 */
3289 SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
3290 SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double);
3291 SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int);
3292 SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
3293 SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int);
3294 SQLITE_API int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*));
3295 SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
3296 SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
3297 SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
3298
3299 /*
3300 ** CAPI3REF: Number Of SQL Parameters
3301 **
3302 ** ^This routine can be used to find the number of [SQL parameters]
3303 ** in a [prepared statement]. SQL parameters are tokens of the
3304 ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
3305 ** placeholders for values that are [sqlite3_bind_blob | bound]
3306 ** to the parameters at a later time.
3307 **
3308 ** ^(This routine actually returns the index of the largest (rightmost)
3309 ** parameter. For all forms except ?NNN, this will correspond to the
3310 ** number of unique parameters. If parameters of the ?NNN form are used,
3311 ** there may be gaps in the list.)^
3312 **
3313 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
3314 ** [sqlite3_bind_parameter_name()], and
3315 ** [sqlite3_bind_parameter_index()].
3316 */
3317 SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*);
3318
3319 /*
3320 ** CAPI3REF: Name Of A Host Parameter
3321 **
3322 ** ^The sqlite3_bind_parameter_name(P,N) interface returns
3323 ** the name of the N-th [SQL parameter] in the [prepared statement] P.
3324 ** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
3325 ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
3326 ** respectively.
3327 ** In other words, the initial ":" or "$" or "@" or "?"
3328 ** is included as part of the name.)^
3329 ** ^Parameters of the form "?" without a following integer have no name
3330 ** and are referred to as "nameless" or "anonymous parameters".
3331 **
3332 ** ^The first host parameter has an index of 1, not 0.
3333 **
3334 ** ^If the value N is out of range or if the N-th parameter is
3335 ** nameless, then NULL is returned. ^The returned string is
3336 ** always in UTF-8 encoding even if the named parameter was
3337 ** originally specified as UTF-16 in [sqlite3_prepare16()] or
3338 ** [sqlite3_prepare16_v2()].
3339 **
3340 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
3341 ** [sqlite3_bind_parameter_count()], and
3342 ** [sqlite3_bind_parameter_index()].
3343 */
3344 SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
3345
3346 /*
3347 ** CAPI3REF: Index Of A Parameter With A Given Name
3348 **
3349 ** ^Return the index of an SQL parameter given its name. ^The
3350 ** index value returned is suitable for use as the second
3351 ** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero
3352 ** is returned if no matching parameter is found. ^The parameter
3353 ** name must be given in UTF-8 even if the original statement
3354 ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()].
3355 **
3356 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
3357 ** [sqlite3_bind_parameter_count()], and
3358 ** [sqlite3_bind_parameter_index()].
3359 */
3360 SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
3361
3362 /*
3363 ** CAPI3REF: Reset All Bindings On A Prepared Statement
3364 **
3365 ** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
3366 ** the [sqlite3_bind_blob | bindings] on a [prepared statement].
3367 ** ^Use this routine to reset all host parameters to NULL.
3368 */
3369 SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*);
3370
3371 /*
3372 ** CAPI3REF: Number Of Columns In A Result Set
3373 **
3374 ** ^Return the number of columns in the result set returned by the
3375 ** [prepared statement]. ^This routine returns 0 if pStmt is an SQL
3376 ** statement that does not return data (for example an [UPDATE]).
3377 **
3378 ** See also: [sqlite3_data_count()]
3379 */
3380 SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt);
3381
3382 /*
3383 ** CAPI3REF: Column Names In A Result Set
3384 **
3385 ** ^These routines return the name assigned to a particular column
3386 ** in the result set of a [SELECT] statement. ^The sqlite3_column_name()
3387 ** interface returns a pointer to a zero-terminated UTF-8 string
3388 ** and sqlite3_column_name16() returns a pointer to a zero-terminated
3389 ** UTF-16 string. ^The first parameter is the [prepared statement]
3390 ** that implements the [SELECT] statement. ^The second parameter is the
3391 ** column number. ^The leftmost column is number 0.
3392 **
3393 ** ^The returned string pointer is valid until either the [prepared statement]
3394 ** is destroyed by [sqlite3_finalize()] or until the statement is automatically
3395 ** reprepared by the first call to [sqlite3_step()] for a particular run
3396 ** or until the next call to
3397 ** sqlite3_column_name() or sqlite3_column_name16() on the same column.
3398 **
3399 ** ^If sqlite3_malloc() fails during the processing of either routine
3400 ** (for example during a conversion from UTF-8 to UTF-16) then a
3401 ** NULL pointer is returned.
3402 **
3403 ** ^The name of a result column is the value of the "AS" clause for
3404 ** that column, if there is an AS clause. If there is no AS clause
3405 ** then the name of the column is unspecified and may change from
3406 ** one release of SQLite to the next.
3407 */
3408 SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N);
3409 SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N);
3410
3411 /*
3412 ** CAPI3REF: Source Of Data In A Query Result
3413 **
3414 ** ^These routines provide a means to determine the database, table, and
3415 ** table column that is the origin of a particular result column in
3416 ** [SELECT] statement.
3417 ** ^The name of the database or table or column can be returned as
3418 ** either a UTF-8 or UTF-16 string. ^The _database_ routines return
3419 ** the database name, the _table_ routines return the table name, and
3420 ** the origin_ routines return the column name.
3421 ** ^The returned string is valid until the [prepared statement] is destroyed
3422 ** using [sqlite3_finalize()] or until the statement is automatically
3423 ** reprepared by the first call to [sqlite3_step()] for a particular run
3424 ** or until the same information is requested
3425 ** again in a different encoding.
3426 **
3427 ** ^The names returned are the original un-aliased names of the
3428 ** database, table, and column.
3429 **
3430 ** ^The first argument to these interfaces is a [prepared statement].
3431 ** ^These functions return information about the Nth result column returned by
3432 ** the statement, where N is the second function argument.
3433 ** ^The left-most column is column 0 for these routines.
3434 **
3435 ** ^If the Nth column returned by the statement is an expression or
3436 ** subquery and is not a column value, then all of these functions return
3437 ** NULL. ^These routine might also return NULL if a memory allocation error
3438 ** occurs. ^Otherwise, they return the name of the attached database, table,
3439 ** or column that query result column was extracted from.
3440 **
3441 ** ^As with all other SQLite APIs, those whose names end with "16" return
3442 ** UTF-16 encoded strings and the other functions return UTF-8.
3443 **
3444 ** ^These APIs are only available if the library was compiled with the
3445 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
3446 **
3447 ** If two or more threads call one or more of these routines against the same
3448 ** prepared statement and column at the same time then the results are
3449 ** undefined.
3450 **
3451 ** If two or more threads call one or more
3452 ** [sqlite3_column_database_name | column metadata interfaces]
3453 ** for the same [prepared statement] and result column
3454 ** at the same time then the results are undefined.
3455 */
3456 SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int);
3457 SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
3458 SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int);
3459 SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
3460 SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
3461 SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
3462
3463 /*
3464 ** CAPI3REF: Declared Datatype Of A Query Result
3465 **
3466 ** ^(The first parameter is a [prepared statement].
3467 ** If this statement is a [SELECT] statement and the Nth column of the
3468 ** returned result set of that [SELECT] is a table column (not an
3469 ** expression or subquery) then the declared type of the table
3470 ** column is returned.)^ ^If the Nth column of the result set is an
3471 ** expression or subquery, then a NULL pointer is returned.
3472 ** ^The returned string is always UTF-8 encoded.
3473 **
3474 ** ^(For example, given the database schema:
3475 **
3476 ** CREATE TABLE t1(c1 VARIANT);
3477 **
3478 ** and the following statement to be compiled:
3479 **
3480 ** SELECT c1 + 1, c1 FROM t1;
3481 **
3482 ** this routine would return the string "VARIANT" for the second result
3483 ** column (i==1), and a NULL pointer for the first result column (i==0).)^
3484 **
3485 ** ^SQLite uses dynamic run-time typing. ^So just because a column
3486 ** is declared to contain a particular type does not mean that the
3487 ** data stored in that column is of the declared type. SQLite is
3488 ** strongly typed, but the typing is dynamic not static. ^Type
3489 ** is associated with individual values, not with the containers
3490 ** used to hold those values.
3491 */
3492 SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int);
3493 SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
3494
3495 /*
3496 ** CAPI3REF: Evaluate An SQL Statement
3497 **
3498 ** After a [prepared statement] has been prepared using either
3499 ** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy
3500 ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
3501 ** must be called one or more times to evaluate the statement.
3502 **
3503 ** The details of the behavior of the sqlite3_step() interface depend
3504 ** on whether the statement was prepared using the newer "v2" interface
3505 ** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy
3506 ** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the
3507 ** new "v2" interface is recommended for new applications but the legacy
3508 ** interface will continue to be supported.
3509 **
3510 ** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
3511 ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
3512 ** ^With the "v2" interface, any of the other [result codes] or
3513 ** [extended result codes] might be returned as well.
3514 **
3515 ** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
3516 ** database locks it needs to do its job. ^If the statement is a [COMMIT]
3517 ** or occurs outside of an explicit transaction, then you can retry the
3518 ** statement. If the statement is not a [COMMIT] and occurs within an
3519 ** explicit transaction then you should rollback the transaction before
3520 ** continuing.
3521 **
3522 ** ^[SQLITE_DONE] means that the statement has finished executing
3523 ** successfully. sqlite3_step() should not be called again on this virtual
3524 ** machine without first calling [sqlite3_reset()] to reset the virtual
3525 ** machine back to its initial state.
3526 **
3527 ** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
3528 ** is returned each time a new row of data is ready for processing by the
3529 ** caller. The values may be accessed using the [column access functions].
3530 ** sqlite3_step() is called again to retrieve the next row of data.
3531 **
3532 ** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
3533 ** violation) has occurred. sqlite3_step() should not be called again on
3534 ** the VM. More information may be found by calling [sqlite3_errmsg()].
3535 ** ^With the legacy interface, a more specific error code (for example,
3536 ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
3537 ** can be obtained by calling [sqlite3_reset()] on the
3538 ** [prepared statement]. ^In the "v2" interface,
3539 ** the more specific error code is returned directly by sqlite3_step().
3540 **
3541 ** [SQLITE_MISUSE] means that the this routine was called inappropriately.
3542 ** Perhaps it was called on a [prepared statement] that has
3543 ** already been [sqlite3_finalize | finalized] or on one that had
3544 ** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could
3545 ** be the case that the same database connection is being used by two or
3546 ** more threads at the same moment in time.
3547 **
3548 ** For all versions of SQLite up to and including 3.6.23.1, a call to
3549 ** [sqlite3_reset()] was required after sqlite3_step() returned anything
3550 ** other than [SQLITE_ROW] before any subsequent invocation of
3551 ** sqlite3_step(). Failure to reset the prepared statement using
3552 ** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
3553 ** sqlite3_step(). But after version 3.6.23.1, sqlite3_step() began
3554 ** calling [sqlite3_reset()] automatically in this circumstance rather
3555 ** than returning [SQLITE_MISUSE]. This is not considered a compatibility
3556 ** break because any application that ever receives an SQLITE_MISUSE error
3557 ** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option
3558 ** can be used to restore the legacy behavior.
3559 **
3560 ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
3561 ** API always returns a generic error code, [SQLITE_ERROR], following any
3562 ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call
3563 ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
3564 ** specific [error codes] that better describes the error.
3565 ** We admit that this is a goofy design. The problem has been fixed
3566 ** with the "v2" interface. If you prepare all of your SQL statements
3567 ** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead
3568 ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
3569 ** then the more specific [error codes] are returned directly
3570 ** by sqlite3_step(). The use of the "v2" interface is recommended.
3571 */
3572 SQLITE_API int sqlite3_step(sqlite3_stmt*);
3573
3574 /*
3575 ** CAPI3REF: Number of columns in a result set
3576 **
3577 ** ^The sqlite3_data_count(P) interface returns the number of columns in the
3578 ** current row of the result set of [prepared statement] P.
3579 ** ^If prepared statement P does not have results ready to return
3580 ** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of
3581 ** interfaces) then sqlite3_data_count(P) returns 0.
3582 ** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
3583 ** ^The sqlite3_data_count(P) routine returns 0 if the previous call to
3584 ** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P)
3585 ** will return non-zero if previous call to [sqlite3_step](P) returned
3586 ** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum]
3587 ** where it always returns zero since each step of that multi-step
3588 ** pragma returns 0 columns of data.
3589 **
3590 ** See also: [sqlite3_column_count()]
3591 */
3592 SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
3593
3594 /*
3595 ** CAPI3REF: Fundamental Datatypes
3596 ** KEYWORDS: SQLITE_TEXT
3597 **
3598 ** ^(Every value in SQLite has one of five fundamental datatypes:
3599 **
3600 ** <ul>
3601 ** <li> 64-bit signed integer
3602 ** <li> 64-bit IEEE floating point number
3603 ** <li> string
3604 ** <li> BLOB
3605 ** <li> NULL
3606 ** </ul>)^
3607 **
3608 ** These constants are codes for each of those types.
3609 **
3610 ** Note that the SQLITE_TEXT constant was also used in SQLite version 2
3611 ** for a completely different meaning. Software that links against both
3612 ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
3613 ** SQLITE_TEXT.
3614 */
3615 #define SQLITE_INTEGER 1
3616 #define SQLITE_FLOAT 2
3617 #define SQLITE_BLOB 4
3618 #define SQLITE_NULL 5
3619 #ifdef SQLITE_TEXT
3620 # undef SQLITE_TEXT
3621 #else
3622 # define SQLITE_TEXT 3
3623 #endif
3624 #define SQLITE3_TEXT 3
3625
3626 /*
3627 ** CAPI3REF: Result Values From A Query
3628 ** KEYWORDS: {column access functions}
3629 **
3630 ** These routines form the "result set" interface.
3631 **
3632 ** ^These routines return information about a single column of the current
3633 ** result row of a query. ^In every case the first argument is a pointer
3634 ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
3635 ** that was returned from [sqlite3_prepare_v2()] or one of its variants)
3636 ** and the second argument is the index of the column for which information
3637 ** should be returned. ^The leftmost column of the result set has the index 0.
3638 ** ^The number of columns in the result can be determined using
3639 ** [sqlite3_column_count()].
3640 **
3641 ** If the SQL statement does not currently point to a valid row, or if the
3642 ** column index is out of range, the result is undefined.
3643 ** These routines may only be called when the most recent call to
3644 ** [sqlite3_step()] has returned [SQLITE_ROW] and neither
3645 ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
3646 ** If any of these routines are called after [sqlite3_reset()] or
3647 ** [sqlite3_finalize()] or after [sqlite3_step()] has returned
3648 ** something other than [SQLITE_ROW], the results are undefined.
3649 ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
3650 ** are called from a different thread while any of these routines
3651 ** are pending, then the results are undefined.
3652 **
3653 ** ^The sqlite3_column_type() routine returns the
3654 ** [SQLITE_INTEGER | datatype code] for the initial data type
3655 ** of the result column. ^The returned value is one of [SQLITE_INTEGER],
3656 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value
3657 ** returned by sqlite3_column_type() is only meaningful if no type
3658 ** conversions have occurred as described below. After a type conversion,
3659 ** the value returned by sqlite3_column_type() is undefined. Future
3660 ** versions of SQLite may change the behavior of sqlite3_column_type()
3661 ** following a type conversion.
3662 **
3663 ** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
3664 ** routine returns the number of bytes in that BLOB or string.
3665 ** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
3666 ** the string to UTF-8 and then returns the number of bytes.
3667 ** ^If the result is a numeric value then sqlite3_column_bytes() uses
3668 ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
3669 ** the number of bytes in that string.
3670 ** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
3671 **
3672 ** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
3673 ** routine returns the number of bytes in that BLOB or string.
3674 ** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
3675 ** the string to UTF-16 and then returns the number of bytes.
3676 ** ^If the result is a numeric value then sqlite3_column_bytes16() uses
3677 ** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
3678 ** the number of bytes in that string.
3679 ** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
3680 **
3681 ** ^The values returned by [sqlite3_column_bytes()] and
3682 ** [sqlite3_column_bytes16()] do not include the zero terminators at the end
3683 ** of the string. ^For clarity: the values returned by
3684 ** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
3685 ** bytes in the string, not the number of characters.
3686 **
3687 ** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
3688 ** even empty strings, are always zero-terminated. ^The return
3689 ** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
3690 **
3691 ** ^The object returned by [sqlite3_column_value()] is an
3692 ** [unprotected sqlite3_value] object. An unprotected sqlite3_value object
3693 ** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()].
3694 ** If the [unprotected sqlite3_value] object returned by
3695 ** [sqlite3_column_value()] is used in any other way, including calls
3696 ** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
3697 ** or [sqlite3_value_bytes()], then the behavior is undefined.
3698 **
3699 ** These routines attempt to convert the value where appropriate. ^For
3700 ** example, if the internal representation is FLOAT and a text result
3701 ** is requested, [sqlite3_snprintf()] is used internally to perform the
3702 ** conversion automatically. ^(The following table details the conversions
3703 ** that are applied:
3704 **
3705 ** <blockquote>
3706 ** <table border="1">
3707 ** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion
3708 **
3709 ** <tr><td> NULL <td> INTEGER <td> Result is 0
3710 ** <tr><td> NULL <td> FLOAT <td> Result is 0.0
3711 ** <tr><td> NULL <td> TEXT <td> Result is NULL pointer
3712 ** <tr><td> NULL <td> BLOB <td> Result is NULL pointer
3713 ** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float
3714 ** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer
3715 ** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT
3716 ** <tr><td> FLOAT <td> INTEGER <td> Convert from float to integer
3717 ** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float
3718 ** <tr><td> FLOAT <td> BLOB <td> Same as FLOAT->TEXT
3719 ** <tr><td> TEXT <td> INTEGER <td> Use atoi()
3720 ** <tr><td> TEXT <td> FLOAT <td> Use atof()
3721 ** <tr><td> TEXT <td> BLOB <td> No change
3722 ** <tr><td> BLOB <td> INTEGER <td> Convert to TEXT then use atoi()
3723 ** <tr><td> BLOB <td> FLOAT <td> Convert to TEXT then use atof()
3724 ** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed
3725 ** </table>
3726 ** </blockquote>)^
3727 **
3728 ** The table above makes reference to standard C library functions atoi()
3729 ** and atof(). SQLite does not really use these functions. It has its
3730 ** own equivalent internal routines. The atoi() and atof() names are
3731 ** used in the table for brevity and because they are familiar to most
3732 ** C programmers.
3733 **
3734 ** Note that when type conversions occur, pointers returned by prior
3735 ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
3736 ** sqlite3_column_text16() may be invalidated.
3737 ** Type conversions and pointer invalidations might occur
3738 ** in the following cases:
3739 **
3740 ** <ul>
3741 ** <li> The initial content is a BLOB and sqlite3_column_text() or
3742 ** sqlite3_column_text16() is called. A zero-terminator might
3743 ** need to be added to the string.</li>
3744 ** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
3745 ** sqlite3_column_text16() is called. The content must be converted
3746 ** to UTF-16.</li>
3747 ** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
3748 ** sqlite3_column_text() is called. The content must be converted
3749 ** to UTF-8.</li>
3750 ** </ul>
3751 **
3752 ** ^Conversions between UTF-16be and UTF-16le are always done in place and do
3753 ** not invalidate a prior pointer, though of course the content of the buffer
3754 ** that the prior pointer references will have been modified. Other kinds
3755 ** of conversion are done in place when it is possible, but sometimes they
3756 ** are not possible and in those cases prior pointers are invalidated.
3757 **
3758 ** The safest and easiest to remember policy is to invoke these routines
3759 ** in one of the following ways:
3760 **
3761 ** <ul>
3762 ** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
3763 ** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
3764 ** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
3765 ** </ul>
3766 **
3767 ** In other words, you should call sqlite3_column_text(),
3768 ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
3769 ** into the desired format, then invoke sqlite3_column_bytes() or
3770 ** sqlite3_column_bytes16() to find the size of the result. Do not mix calls
3771 ** to sqlite3_column_text() or sqlite3_column_blob() with calls to
3772 ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
3773 ** with calls to sqlite3_column_bytes().
3774 **
3775 ** ^The pointers returned are valid until a type conversion occurs as
3776 ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
3777 ** [sqlite3_finalize()] is called. ^The memory space used to hold strings
3778 ** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned
3779 ** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
3780 ** [sqlite3_free()].
3781 **
3782 ** ^(If a memory allocation error occurs during the evaluation of any
3783 ** of these routines, a default value is returned. The default value
3784 ** is either the integer 0, the floating point number 0.0, or a NULL
3785 ** pointer. Subsequent calls to [sqlite3_errcode()] will return
3786 ** [SQLITE_NOMEM].)^
3787 */
3788 SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
3789 SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
3790 SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
3791 SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol);
3792 SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol);
3793 SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
3794 SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
3795 SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
3796 SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol);
3797 SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
3798
3799 /*
3800 ** CAPI3REF: Destroy A Prepared Statement Object
3801 **
3802 ** ^The sqlite3_finalize() function is called to delete a [prepared statement].
3803 ** ^If the most recent evaluation of the statement encountered no errors
3804 ** or if the statement is never been evaluated, then sqlite3_finalize() returns
3805 ** SQLITE_OK. ^If the most recent evaluation of statement S failed, then
3806 ** sqlite3_finalize(S) returns the appropriate [error code] or
3807 ** [extended error code].
3808 **
3809 ** ^The sqlite3_finalize(S) routine can be called at any point during
3810 ** the life cycle of [prepared statement] S:
3811 ** before statement S is ever evaluated, after
3812 ** one or more calls to [sqlite3_reset()], or after any call
3813 ** to [sqlite3_step()] regardless of whether or not the statement has
3814 ** completed execution.
3815 **
3816 ** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
3817 **
3818 ** The application must finalize every [prepared statement] in order to avoid
3819 ** resource leaks. It is a grievous error for the application to try to use
3820 ** a prepared statement after it has been finalized. Any use of a prepared
3821 ** statement after it has been finalized can result in undefined and
3822 ** undesirable behavior such as segfaults and heap corruption.
3823 */
3824 SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt);
3825
3826 /*
3827 ** CAPI3REF: Reset A Prepared Statement Object
3828 **
3829 ** The sqlite3_reset() function is called to reset a [prepared statement]
3830 ** object back to its initial state, ready to be re-executed.
3831 ** ^Any SQL statement variables that had values bound to them using
3832 ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
3833 ** Use [sqlite3_clear_bindings()] to reset the bindings.
3834 **
3835 ** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
3836 ** back to the beginning of its program.
3837 **
3838 ** ^If the most recent call to [sqlite3_step(S)] for the
3839 ** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
3840 ** or if [sqlite3_step(S)] has never before been called on S,
3841 ** then [sqlite3_reset(S)] returns [SQLITE_OK].
3842 **
3843 ** ^If the most recent call to [sqlite3_step(S)] for the
3844 ** [prepared statement] S indicated an error, then
3845 ** [sqlite3_reset(S)] returns an appropriate [error code].
3846 **
3847 ** ^The [sqlite3_reset(S)] interface does not change the values
3848 ** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
3849 */
3850 SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt);
3851
3852 /*
3853 ** CAPI3REF: Create Or Redefine SQL Functions
3854 ** KEYWORDS: {function creation routines}
3855 ** KEYWORDS: {application-defined SQL function}
3856 ** KEYWORDS: {application-defined SQL functions}
3857 **
3858 ** ^These functions (collectively known as "function creation routines")
3859 ** are used to add SQL functions or aggregates or to redefine the behavior
3860 ** of existing SQL functions or aggregates. The only differences between
3861 ** these routines are the text encoding expected for
3862 ** the second parameter (the name of the function being created)
3863 ** and the presence or absence of a destructor callback for
3864 ** the application data pointer.
3865 **
3866 ** ^The first parameter is the [database connection] to which the SQL
3867 ** function is to be added. ^If an application uses more than one database
3868 ** connection then application-defined SQL functions must be added
3869 ** to each database connection separately.
3870 **
3871 ** ^The second parameter is the name of the SQL function to be created or
3872 ** redefined. ^The length of the name is limited to 255 bytes in a UTF-8
3873 ** representation, exclusive of the zero-terminator. ^Note that the name
3874 ** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
3875 ** ^Any attempt to create a function with a longer name
3876 ** will result in [SQLITE_MISUSE] being returned.
3877 **
3878 ** ^The third parameter (nArg)
3879 ** is the number of arguments that the SQL function or
3880 ** aggregate takes. ^If this parameter is -1, then the SQL function or
3881 ** aggregate may take any number of arguments between 0 and the limit
3882 ** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third
3883 ** parameter is less than -1 or greater than 127 then the behavior is
3884 ** undefined.
3885 **
3886 ** ^The fourth parameter, eTextRep, specifies what
3887 ** [SQLITE_UTF8 | text encoding] this SQL function prefers for
3888 ** its parameters. Every SQL function implementation must be able to work
3889 ** with UTF-8, UTF-16le, or UTF-16be. But some implementations may be
3890 ** more efficient with one encoding than another. ^An application may
3891 ** invoke sqlite3_create_function() or sqlite3_create_function16() multiple
3892 ** times with the same function but with different values of eTextRep.
3893 ** ^When multiple implementations of the same function are available, SQLite
3894 ** will pick the one that involves the least amount of data conversion.
3895 ** If there is only a single implementation which does not care what text
3896 ** encoding is used, then the fourth argument should be [SQLITE_ANY].
3897 **
3898 ** ^(The fifth parameter is an arbitrary pointer. The implementation of the
3899 ** function can gain access to this pointer using [sqlite3_user_data()].)^
3900 **
3901 ** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are
3902 ** pointers to C-language functions that implement the SQL function or
3903 ** aggregate. ^A scalar SQL function requires an implementation of the xFunc
3904 ** callback only; NULL pointers must be passed as the xStep and xFinal
3905 ** parameters. ^An aggregate SQL function requires an implementation of xStep
3906 ** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
3907 ** SQL function or aggregate, pass NULL pointers for all three function
3908 ** callbacks.
3909 **
3910 ** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL,
3911 ** then it is destructor for the application data pointer.
3912 ** The destructor is invoked when the function is deleted, either by being
3913 ** overloaded or when the database connection closes.)^
3914 ** ^The destructor is also invoked if the call to
3915 ** sqlite3_create_function_v2() fails.
3916 ** ^When the destructor callback of the tenth parameter is invoked, it
3917 ** is passed a single argument which is a copy of the application data
3918 ** pointer which was the fifth parameter to sqlite3_create_function_v2().
3919 **
3920 ** ^It is permitted to register multiple implementations of the same
3921 ** functions with the same name but with either differing numbers of
3922 ** arguments or differing preferred text encodings. ^SQLite will use
3923 ** the implementation that most closely matches the way in which the
3924 ** SQL function is used. ^A function implementation with a non-negative
3925 ** nArg parameter is a better match than a function implementation with
3926 ** a negative nArg. ^A function where the preferred text encoding
3927 ** matches the database encoding is a better
3928 ** match than a function where the encoding is different.
3929 ** ^A function where the encoding difference is between UTF16le and UTF16be
3930 ** is a closer match than a function where the encoding difference is
3931 ** between UTF8 and UTF16.
3932 **
3933 ** ^Built-in functions may be overloaded by new application-defined functions.
3934 **
3935 ** ^An application-defined function is permitted to call other
3936 ** SQLite interfaces. However, such calls must not
3937 ** close the database connection nor finalize or reset the prepared
3938 ** statement in which the function is running.
3939 */
3940 SQLITE_API int sqlite3_create_function(
3941 sqlite3 *db,
3942 const char *zFunctionName,
3943 int nArg,
3944 int eTextRep,
3945 void *pApp,
3946 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
3947 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
3948 void (*xFinal)(sqlite3_context*)
3949 );
3950 SQLITE_API int sqlite3_create_function16(
3951 sqlite3 *db,
3952 const void *zFunctionName,
3953 int nArg,
3954 int eTextRep,
3955 void *pApp,
3956 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
3957 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
3958 void (*xFinal)(sqlite3_context*)
3959 );
3960 SQLITE_API int sqlite3_create_function_v2(
3961 sqlite3 *db,
3962 const char *zFunctionName,
3963 int nArg,
3964 int eTextRep,
3965 void *pApp,
3966 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
3967 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
3968 void (*xFinal)(sqlite3_context*),
3969 void(*xDestroy)(void*)
3970 );
3971
3972 /*
3973 ** CAPI3REF: Text Encodings
3974 **
3975 ** These constant define integer codes that represent the various
3976 ** text encodings supported by SQLite.
3977 */
3978 #define SQLITE_UTF8 1
3979 #define SQLITE_UTF16LE 2
3980 #define SQLITE_UTF16BE 3
3981 #define SQLITE_UTF16 4 /* Use native byte order */
3982 #define SQLITE_ANY 5 /* sqlite3_create_function only */
3983 #define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */
3984
3985 /*
3986 ** CAPI3REF: Deprecated Functions
3987 ** DEPRECATED
3988 **
3989 ** These functions are [deprecated]. In order to maintain
3990 ** backwards compatibility with older code, these functions continue
3991 ** to be supported. However, new applications should avoid
3992 ** the use of these functions. To help encourage people to avoid
3993 ** using these functions, we are not going to tell you what they do.
3994 */
3995 #ifndef SQLITE_OMIT_DEPRECATED
3996 SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
3997 SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
3998 SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
3999 SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void);
4000 SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
4001 SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64);
4002 #endif
4003
4004 /*
4005 ** CAPI3REF: Obtaining SQL Function Parameter Values
4006 **
4007 ** The C-language implementation of SQL functions and aggregates uses
4008 ** this set of interface routines to access the parameter values on
4009 ** the function or aggregate.
4010 **
4011 ** The xFunc (for scalar functions) or xStep (for aggregates) parameters
4012 ** to [sqlite3_create_function()] and [sqlite3_create_function16()]
4013 ** define callbacks that implement the SQL functions and aggregates.
4014 ** The 3rd parameter to these callbacks is an array of pointers to
4015 ** [protected sqlite3_value] objects. There is one [sqlite3_value] object for
4016 ** each parameter to the SQL function. These routines are used to
4017 ** extract values from the [sqlite3_value] objects.
4018 **
4019 ** These routines work only with [protected sqlite3_value] objects.
4020 ** Any attempt to use these routines on an [unprotected sqlite3_value]
4021 ** object results in undefined behavior.
4022 **
4023 ** ^These routines work just like the corresponding [column access functions]
4024 ** except that these routines take a single [protected sqlite3_value] object
4025 ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
4026 **
4027 ** ^The sqlite3_value_text16() interface extracts a UTF-16 string
4028 ** in the native byte-order of the host machine. ^The
4029 ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
4030 ** extract UTF-16 strings as big-endian and little-endian respectively.
4031 **
4032 ** ^(The sqlite3_value_numeric_type() interface attempts to apply
4033 ** numeric affinity to the value. This means that an attempt is
4034 ** made to convert the value to an integer or floating point. If
4035 ** such a conversion is possible without loss of information (in other
4036 ** words, if the value is a string that looks like a number)
4037 ** then the conversion is performed. Otherwise no conversion occurs.
4038 ** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
4039 **
4040 ** Please pay particular attention to the fact that the pointer returned
4041 ** from [sqlite3_value_blob()], [sqlite3_value_text()], or
4042 ** [sqlite3_value_text16()] can be invalidated by a subsequent call to
4043 ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
4044 ** or [sqlite3_value_text16()].
4045 **
4046 ** These routines must be called from the same thread as
4047 ** the SQL function that supplied the [sqlite3_value*] parameters.
4048 */
4049 SQLITE_API const void *sqlite3_value_blob(sqlite3_value*);
4050 SQLITE_API int sqlite3_value_bytes(sqlite3_value*);
4051 SQLITE_API int sqlite3_value_bytes16(sqlite3_value*);
4052 SQLITE_API double sqlite3_value_double(sqlite3_value*);
4053 SQLITE_API int sqlite3_value_int(sqlite3_value*);
4054 SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
4055 SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*);
4056 SQLITE_API const void *sqlite3_value_text16(sqlite3_value*);
4057 SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*);
4058 SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*);
4059 SQLITE_API int sqlite3_value_type(sqlite3_value*);
4060 SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*);
4061
4062 /*
4063 ** CAPI3REF: Obtain Aggregate Function Context
4064 **
4065 ** Implementations of aggregate SQL functions use this
4066 ** routine to allocate memory for storing their state.
4067 **
4068 ** ^The first time the sqlite3_aggregate_context(C,N) routine is called
4069 ** for a particular aggregate function, SQLite
4070 ** allocates N of memory, zeroes out that memory, and returns a pointer
4071 ** to the new memory. ^On second and subsequent calls to
4072 ** sqlite3_aggregate_context() for the same aggregate function instance,
4073 ** the same buffer is returned. Sqlite3_aggregate_context() is normally
4074 ** called once for each invocation of the xStep callback and then one
4075 ** last time when the xFinal callback is invoked. ^(When no rows match
4076 ** an aggregate query, the xStep() callback of the aggregate function
4077 ** implementation is never called and xFinal() is called exactly once.
4078 ** In those cases, sqlite3_aggregate_context() might be called for the
4079 ** first time from within xFinal().)^
4080 **
4081 ** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer if N is
4082 ** less than or equal to zero or if a memory allocate error occurs.
4083 **
4084 ** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
4085 ** determined by the N parameter on first successful call. Changing the
4086 ** value of N in subsequent call to sqlite3_aggregate_context() within
4087 ** the same aggregate function instance will not resize the memory
4088 ** allocation.)^
4089 **
4090 ** ^SQLite automatically frees the memory allocated by
4091 ** sqlite3_aggregate_context() when the aggregate query concludes.
4092 **
4093 ** The first parameter must be a copy of the
4094 ** [sqlite3_context | SQL function context] that is the first parameter
4095 ** to the xStep or xFinal callback routine that implements the aggregate
4096 ** function.
4097 **
4098 ** This routine must be called from the same thread in which
4099 ** the aggregate SQL function is running.
4100 */
4101 SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
4102
4103 /*
4104 ** CAPI3REF: User Data For Functions
4105 **
4106 ** ^The sqlite3_user_data() interface returns a copy of
4107 ** the pointer that was the pUserData parameter (the 5th parameter)
4108 ** of the [sqlite3_create_function()]
4109 ** and [sqlite3_create_function16()] routines that originally
4110 ** registered the application defined function.
4111 **
4112 ** This routine must be called from the same thread in which
4113 ** the application-defined function is running.
4114 */
4115 SQLITE_API void *sqlite3_user_data(sqlite3_context*);
4116
4117 /*
4118 ** CAPI3REF: Database Connection For Functions
4119 **
4120 ** ^The sqlite3_context_db_handle() interface returns a copy of
4121 ** the pointer to the [database connection] (the 1st parameter)
4122 ** of the [sqlite3_create_function()]
4123 ** and [sqlite3_create_function16()] routines that originally
4124 ** registered the application defined function.
4125 */
4126 SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
4127
4128 /*
4129 ** CAPI3REF: Function Auxiliary Data
4130 **
4131 ** The following two functions may be used by scalar SQL functions to
4132 ** associate metadata with argument values. If the same value is passed to
4133 ** multiple invocations of the same SQL function during query execution, under
4134 ** some circumstances the associated metadata may be preserved. This may
4135 ** be used, for example, to add a regular-expression matching scalar
4136 ** function. The compiled version of the regular expression is stored as
4137 ** metadata associated with the SQL value passed as the regular expression
4138 ** pattern. The compiled regular expression can be reused on multiple
4139 ** invocations of the same function so that the original pattern string
4140 ** does not need to be recompiled on each invocation.
4141 **
4142 ** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata
4143 ** associated by the sqlite3_set_auxdata() function with the Nth argument
4144 ** value to the application-defined function. ^If no metadata has been ever
4145 ** been set for the Nth argument of the function, or if the corresponding
4146 ** function parameter has changed since the meta-data was set,
4147 ** then sqlite3_get_auxdata() returns a NULL pointer.
4148 **
4149 ** ^The sqlite3_set_auxdata() interface saves the metadata
4150 ** pointed to by its 3rd parameter as the metadata for the N-th
4151 ** argument of the application-defined function. Subsequent
4152 ** calls to sqlite3_get_auxdata() might return this data, if it has
4153 ** not been destroyed.
4154 ** ^If it is not NULL, SQLite will invoke the destructor
4155 ** function given by the 4th parameter to sqlite3_set_auxdata() on
4156 ** the metadata when the corresponding function parameter changes
4157 ** or when the SQL statement completes, whichever comes first.
4158 **
4159 ** SQLite is free to call the destructor and drop metadata on any
4160 ** parameter of any function at any time. ^The only guarantee is that
4161 ** the destructor will be called before the metadata is dropped.
4162 **
4163 ** ^(In practice, metadata is preserved between function calls for
4164 ** expressions that are constant at compile time. This includes literal
4165 ** values and [parameters].)^
4166 **
4167 ** These routines must be called from the same thread in which
4168 ** the SQL function is running.
4169 */
4170 SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N);
4171 SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
4172
4173
4174 /*
4175 ** CAPI3REF: Constants Defining Special Destructor Behavior
4176 **
4177 ** These are special values for the destructor that is passed in as the
4178 ** final argument to routines like [sqlite3_result_blob()]. ^If the destructor
4179 ** argument is SQLITE_STATIC, it means that the content pointer is constant
4180 ** and will never change. It does not need to be destroyed. ^The
4181 ** SQLITE_TRANSIENT value means that the content will likely change in
4182 ** the near future and that SQLite should make its own private copy of
4183 ** the content before returning.
4184 **
4185 ** The typedef is necessary to work around problems in certain
4186 ** C++ compilers. See ticket #2191.
4187 */
4188 typedef void (*sqlite3_destructor_type)(void*);
4189 #define SQLITE_STATIC ((sqlite3_destructor_type)0)
4190 #define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1)
4191
4192 /*
4193 ** CAPI3REF: Setting The Result Of An SQL Function
4194 **
4195 ** These routines are used by the xFunc or xFinal callbacks that
4196 ** implement SQL functions and aggregates. See
4197 ** [sqlite3_create_function()] and [sqlite3_create_function16()]
4198 ** for additional information.
4199 **
4200 ** These functions work very much like the [parameter binding] family of
4201 ** functions used to bind values to host parameters in prepared statements.
4202 ** Refer to the [SQL parameter] documentation for additional information.
4203 **
4204 ** ^The sqlite3_result_blob() interface sets the result from
4205 ** an application-defined function to be the BLOB whose content is pointed
4206 ** to by the second parameter and which is N bytes long where N is the
4207 ** third parameter.
4208 **
4209 ** ^The sqlite3_result_zeroblob() interfaces set the result of
4210 ** the application-defined function to be a BLOB containing all zero
4211 ** bytes and N bytes in size, where N is the value of the 2nd parameter.
4212 **
4213 ** ^The sqlite3_result_double() interface sets the result from
4214 ** an application-defined function to be a floating point value specified
4215 ** by its 2nd argument.
4216 **
4217 ** ^The sqlite3_result_error() and sqlite3_result_error16() functions
4218 ** cause the implemented SQL function to throw an exception.
4219 ** ^SQLite uses the string pointed to by the
4220 ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
4221 ** as the text of an error message. ^SQLite interprets the error
4222 ** message string from sqlite3_result_error() as UTF-8. ^SQLite
4223 ** interprets the string from sqlite3_result_error16() as UTF-16 in native
4224 ** byte order. ^If the third parameter to sqlite3_result_error()
4225 ** or sqlite3_result_error16() is negative then SQLite takes as the error
4226 ** message all text up through the first zero character.
4227 ** ^If the third parameter to sqlite3_result_error() or
4228 ** sqlite3_result_error16() is non-negative then SQLite takes that many
4229 ** bytes (not characters) from the 2nd parameter as the error message.
4230 ** ^The sqlite3_result_error() and sqlite3_result_error16()
4231 ** routines make a private copy of the error message text before
4232 ** they return. Hence, the calling function can deallocate or
4233 ** modify the text after they return without harm.
4234 ** ^The sqlite3_result_error_code() function changes the error code
4235 ** returned by SQLite as a result of an error in a function. ^By default,
4236 ** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error()
4237 ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
4238 **
4239 ** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an
4240 ** error indicating that a string or BLOB is too long to represent.
4241 **
4242 ** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an
4243 ** error indicating that a memory allocation failed.
4244 **
4245 ** ^The sqlite3_result_int() interface sets the return value
4246 ** of the application-defined function to be the 32-bit signed integer
4247 ** value given in the 2nd argument.
4248 ** ^The sqlite3_result_int64() interface sets the return value
4249 ** of the application-defined function to be the 64-bit signed integer
4250 ** value given in the 2nd argument.
4251 **
4252 ** ^The sqlite3_result_null() interface sets the return value
4253 ** of the application-defined function to be NULL.
4254 **
4255 ** ^The sqlite3_result_text(), sqlite3_result_text16(),
4256 ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
4257 ** set the return value of the application-defined function to be
4258 ** a text string which is represented as UTF-8, UTF-16 native byte order,
4259 ** UTF-16 little endian, or UTF-16 big endian, respectively.
4260 ** ^SQLite takes the text result from the application from
4261 ** the 2nd parameter of the sqlite3_result_text* interfaces.
4262 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
4263 ** is negative, then SQLite takes result text from the 2nd parameter
4264 ** through the first zero character.
4265 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
4266 ** is non-negative, then as many bytes (not characters) of the text
4267 ** pointed to by the 2nd parameter are taken as the application-defined
4268 ** function result. If the 3rd parameter is non-negative, then it
4269 ** must be the byte offset into the string where the NUL terminator would
4270 ** appear if the string where NUL terminated. If any NUL characters occur
4271 ** in the string at a byte offset that is less than the value of the 3rd
4272 ** parameter, then the resulting string will contain embedded NULs and the
4273 ** result of expressions operating on strings with embedded NULs is undefined.
4274 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
4275 ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
4276 ** function as the destructor on the text or BLOB result when it has
4277 ** finished using that result.
4278 ** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
4279 ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
4280 ** assumes that the text or BLOB result is in constant space and does not
4281 ** copy the content of the parameter nor call a destructor on the content
4282 ** when it has finished using that result.
4283 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
4284 ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
4285 ** then SQLite makes a copy of the result into space obtained from
4286 ** from [sqlite3_malloc()] before it returns.
4287 **
4288 ** ^The sqlite3_result_value() interface sets the result of
4289 ** the application-defined function to be a copy the
4290 ** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The
4291 ** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
4292 ** so that the [sqlite3_value] specified in the parameter may change or
4293 ** be deallocated after sqlite3_result_value() returns without harm.
4294 ** ^A [protected sqlite3_value] object may always be used where an
4295 ** [unprotected sqlite3_value] object is required, so either
4296 ** kind of [sqlite3_value] object can be used with this interface.
4297 **
4298 ** If these routines are called from within the different thread
4299 ** than the one containing the application-defined function that received
4300 ** the [sqlite3_context] pointer, the results are undefined.
4301 */
4302 SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
4303 SQLITE_API void sqlite3_result_double(sqlite3_context*, double);
4304 SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int);
4305 SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int);
4306 SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*);
4307 SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*);
4308 SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int);
4309 SQLITE_API void sqlite3_result_int(sqlite3_context*, int);
4310 SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
4311 SQLITE_API void sqlite3_result_null(sqlite3_context*);
4312 SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
4313 SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
4314 SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
4315 SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
4316 SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
4317 SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n);
4318
4319 /*
4320 ** CAPI3REF: Define New Collating Sequences
4321 **
4322 ** ^These functions add, remove, or modify a [collation] associated
4323 ** with the [database connection] specified as the first argument.
4324 **
4325 ** ^The name of the collation is a UTF-8 string
4326 ** for sqlite3_create_collation() and sqlite3_create_collation_v2()
4327 ** and a UTF-16 string in native byte order for sqlite3_create_collation16().
4328 ** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
4329 ** considered to be the same name.
4330 **
4331 ** ^(The third argument (eTextRep) must be one of the constants:
4332 ** <ul>
4333 ** <li> [SQLITE_UTF8],
4334 ** <li> [SQLITE_UTF16LE],
4335 ** <li> [SQLITE_UTF16BE],
4336 ** <li> [SQLITE_UTF16], or
4337 ** <li> [SQLITE_UTF16_ALIGNED].
4338 ** </ul>)^
4339 ** ^The eTextRep argument determines the encoding of strings passed
4340 ** to the collating function callback, xCallback.
4341 ** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
4342 ** force strings to be UTF16 with native byte order.
4343 ** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
4344 ** on an even byte address.
4345 **
4346 ** ^The fourth argument, pArg, is an application data pointer that is passed
4347 ** through as the first argument to the collating function callback.
4348 **
4349 ** ^The fifth argument, xCallback, is a pointer to the collating function.
4350 ** ^Multiple collating functions can be registered using the same name but
4351 ** with different eTextRep parameters and SQLite will use whichever
4352 ** function requires the least amount of data transformation.
4353 ** ^If the xCallback argument is NULL then the collating function is
4354 ** deleted. ^When all collating functions having the same name are deleted,
4355 ** that collation is no longer usable.
4356 **
4357 ** ^The collating function callback is invoked with a copy of the pArg
4358 ** application data pointer and with two strings in the encoding specified
4359 ** by the eTextRep argument. The collating function must return an
4360 ** integer that is negative, zero, or positive
4361 ** if the first string is less than, equal to, or greater than the second,
4362 ** respectively. A collating function must always return the same answer
4363 ** given the same inputs. If two or more collating functions are registered
4364 ** to the same collation name (using different eTextRep values) then all
4365 ** must give an equivalent answer when invoked with equivalent strings.
4366 ** The collating function must obey the following properties for all
4367 ** strings A, B, and C:
4368 **
4369 ** <ol>
4370 ** <li> If A==B then B==A.
4371 ** <li> If A==B and B==C then A==C.
4372 ** <li> If A&lt;B THEN B&gt;A.
4373 ** <li> If A&lt;B and B&lt;C then A&lt;C.
4374 ** </ol>
4375 **
4376 ** If a collating function fails any of the above constraints and that
4377 ** collating function is registered and used, then the behavior of SQLite
4378 ** is undefined.
4379 **
4380 ** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
4381 ** with the addition that the xDestroy callback is invoked on pArg when
4382 ** the collating function is deleted.
4383 ** ^Collating functions are deleted when they are overridden by later
4384 ** calls to the collation creation functions or when the
4385 ** [database connection] is closed using [sqlite3_close()].
4386 **
4387 ** ^The xDestroy callback is <u>not</u> called if the
4388 ** sqlite3_create_collation_v2() function fails. Applications that invoke
4389 ** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
4390 ** check the return code and dispose of the application data pointer
4391 ** themselves rather than expecting SQLite to deal with it for them.
4392 ** This is different from every other SQLite interface. The inconsistency
4393 ** is unfortunate but cannot be changed without breaking backwards
4394 ** compatibility.
4395 **
4396 ** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
4397 */
4398 SQLITE_API int sqlite3_create_collation(
4399 sqlite3*,
4400 const char *zName,
4401 int eTextRep,
4402 void *pArg,
4403 int(*xCompare)(void*,int,const void*,int,const void*)
4404 );
4405 SQLITE_API int sqlite3_create_collation_v2(
4406 sqlite3*,
4407 const char *zName,
4408 int eTextRep,
4409 void *pArg,
4410 int(*xCompare)(void*,int,const void*,int,const void*),
4411 void(*xDestroy)(void*)
4412 );
4413 SQLITE_API int sqlite3_create_collation16(
4414 sqlite3*,
4415 const void *zName,
4416 int eTextRep,
4417 void *pArg,
4418 int(*xCompare)(void*,int,const void*,int,const void*)
4419 );
4420
4421 /*
4422 ** CAPI3REF: Collation Needed Callbacks
4423 **
4424 ** ^To avoid having to register all collation sequences before a database
4425 ** can be used, a single callback function may be registered with the
4426 ** [database connection] to be invoked whenever an undefined collation
4427 ** sequence is required.
4428 **
4429 ** ^If the function is registered using the sqlite3_collation_needed() API,
4430 ** then it is passed the names of undefined collation sequences as strings
4431 ** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
4432 ** the names are passed as UTF-16 in machine native byte order.
4433 ** ^A call to either function replaces the existing collation-needed callback.
4434 **
4435 ** ^(When the callback is invoked, the first argument passed is a copy
4436 ** of the second argument to sqlite3_collation_needed() or
4437 ** sqlite3_collation_needed16(). The second argument is the database
4438 ** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
4439 ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
4440 ** sequence function required. The fourth parameter is the name of the
4441 ** required collation sequence.)^
4442 **
4443 ** The callback function should register the desired collation using
4444 ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
4445 ** [sqlite3_create_collation_v2()].
4446 */
4447 SQLITE_API int sqlite3_collation_needed(
4448 sqlite3*,
4449 void*,
4450 void(*)(void*,sqlite3*,int eTextRep,const char*)
4451 );
4452 SQLITE_API int sqlite3_collation_needed16(
4453 sqlite3*,
4454 void*,
4455 void(*)(void*,sqlite3*,int eTextRep,const void*)
4456 );
4457
4458 #ifdef SQLITE_HAS_CODEC
4459 /*
4460 ** Specify the key for an encrypted database. This routine should be
4461 ** called right after sqlite3_open().
4462 **
4463 ** The code to implement this API is not available in the public release
4464 ** of SQLite.
4465 */
4466 SQLITE_API int sqlite3_key(
4467 sqlite3 *db, /* Database to be rekeyed */
4468 const void *pKey, int nKey /* The key */
4469 );
4470
4471 /*
4472 ** Change the key on an open database. If the current database is not
4473 ** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the
4474 ** database is decrypted.
4475 **
4476 ** The code to implement this API is not available in the public release
4477 ** of SQLite.
4478 */
4479 SQLITE_API int sqlite3_rekey(
4480 sqlite3 *db, /* Database to be rekeyed */
4481 const void *pKey, int nKey /* The new key */
4482 );
4483
4484 /*
4485 ** Specify the activation key for a SEE database. Unless
4486 ** activated, none of the SEE routines will work.
4487 */
4488 SQLITE_API void sqlite3_activate_see(
4489 const char *zPassPhrase /* Activation phrase */
4490 );
4491 #endif
4492
4493 #ifdef SQLITE_ENABLE_CEROD
4494 /*
4495 ** Specify the activation key for a CEROD database. Unless
4496 ** activated, none of the CEROD routines will work.
4497 */
4498 SQLITE_API void sqlite3_activate_cerod(
4499 const char *zPassPhrase /* Activation phrase */
4500 );
4501 #endif
4502
4503 /*
4504 ** CAPI3REF: Suspend Execution For A Short Time
4505 **
4506 ** The sqlite3_sleep() function causes the current thread to suspend execution
4507 ** for at least a number of milliseconds specified in its parameter.
4508 **
4509 ** If the operating system does not support sleep requests with
4510 ** millisecond time resolution, then the time will be rounded up to
4511 ** the nearest second. The number of milliseconds of sleep actually
4512 ** requested from the operating system is returned.
4513 **
4514 ** ^SQLite implements this interface by calling the xSleep()
4515 ** method of the default [sqlite3_vfs] object. If the xSleep() method
4516 ** of the default VFS is not implemented correctly, or not implemented at
4517 ** all, then the behavior of sqlite3_sleep() may deviate from the description
4518 ** in the previous paragraphs.
4519 */
4520 SQLITE_API int sqlite3_sleep(int);
4521
4522 /*
4523 ** CAPI3REF: Name Of The Folder Holding Temporary Files
4524 **
4525 ** ^(If this global variable is made to point to a string which is
4526 ** the name of a folder (a.k.a. directory), then all temporary files
4527 ** created by SQLite when using a built-in [sqlite3_vfs | VFS]
4528 ** will be placed in that directory.)^ ^If this variable
4529 ** is a NULL pointer, then SQLite performs a search for an appropriate
4530 ** temporary file directory.
4531 **
4532 ** It is not safe to read or modify this variable in more than one
4533 ** thread at a time. It is not safe to read or modify this variable
4534 ** if a [database connection] is being used at the same time in a separate
4535 ** thread.
4536 ** It is intended that this variable be set once
4537 ** as part of process initialization and before any SQLite interface
4538 ** routines have been called and that this variable remain unchanged
4539 ** thereafter.
4540 **
4541 ** ^The [temp_store_directory pragma] may modify this variable and cause
4542 ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,
4543 ** the [temp_store_directory pragma] always assumes that any string
4544 ** that this variable points to is held in memory obtained from
4545 ** [sqlite3_malloc] and the pragma may attempt to free that memory
4546 ** using [sqlite3_free].
4547 ** Hence, if this variable is modified directly, either it should be
4548 ** made NULL or made to point to memory obtained from [sqlite3_malloc]
4549 ** or else the use of the [temp_store_directory pragma] should be avoided.
4550 **
4551 ** <b>Note to Windows Runtime users:</b> The temporary directory must be set
4552 ** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various
4553 ** features that require the use of temporary files may fail. Here is an
4554 ** example of how to do this using C++ with the Windows Runtime:
4555 **
4556 ** <blockquote><pre>
4557 ** LPCWSTR zPath = Windows::Storage::ApplicationData::Current->
4558 ** &nbsp; TemporaryFolder->Path->Data();
4559 ** char zPathBuf&#91;MAX_PATH + 1&#93;;
4560 ** memset(zPathBuf, 0, sizeof(zPathBuf));
4561 ** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),
4562 ** &nbsp; NULL, NULL);
4563 ** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);
4564 ** </pre></blockquote>
4565 */
4566 SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory;
4567
4568 /*
4569 ** CAPI3REF: Name Of The Folder Holding Database Files
4570 **
4571 ** ^(If this global variable is made to point to a string which is
4572 ** the name of a folder (a.k.a. directory), then all database files
4573 ** specified with a relative pathname and created or accessed by
4574 ** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed
4575 ** to be relative to that directory.)^ ^If this variable is a NULL
4576 ** pointer, then SQLite assumes that all database files specified
4577 ** with a relative pathname are relative to the current directory
4578 ** for the process. Only the windows VFS makes use of this global
4579 ** variable; it is ignored by the unix VFS.
4580 **
4581 ** Changing the value of this variable while a database connection is
4582 ** open can result in a corrupt database.
4583 **
4584 ** It is not safe to read or modify this variable in more than one
4585 ** thread at a time. It is not safe to read or modify this variable
4586 ** if a [database connection] is being used at the same time in a separate
4587 ** thread.
4588 ** It is intended that this variable be set once
4589 ** as part of process initialization and before any SQLite interface
4590 ** routines have been called and that this variable remain unchanged
4591 ** thereafter.
4592 **
4593 ** ^The [data_store_directory pragma] may modify this variable and cause
4594 ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,
4595 ** the [data_store_directory pragma] always assumes that any string
4596 ** that this variable points to is held in memory obtained from
4597 ** [sqlite3_malloc] and the pragma may attempt to free that memory
4598 ** using [sqlite3_free].
4599 ** Hence, if this variable is modified directly, either it should be
4600 ** made NULL or made to point to memory obtained from [sqlite3_malloc]
4601 ** or else the use of the [data_store_directory pragma] should be avoided.
4602 */
4603 SQLITE_API SQLITE_EXTERN char *sqlite3_data_directory;
4604
4605 /*
4606 ** CAPI3REF: Test For Auto-Commit Mode
4607 ** KEYWORDS: {autocommit mode}
4608 **
4609 ** ^The sqlite3_get_autocommit() interface returns non-zero or
4610 ** zero if the given database connection is or is not in autocommit mode,
4611 ** respectively. ^Autocommit mode is on by default.
4612 ** ^Autocommit mode is disabled by a [BEGIN] statement.
4613 ** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
4614 **
4615 ** If certain kinds of errors occur on a statement within a multi-statement
4616 ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
4617 ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
4618 ** transaction might be rolled back automatically. The only way to
4619 ** find out whether SQLite automatically rolled back the transaction after
4620 ** an error is to use this function.
4621 **
4622 ** If another thread changes the autocommit status of the database
4623 ** connection while this routine is running, then the return value
4624 ** is undefined.
4625 */
4626 SQLITE_API int sqlite3_get_autocommit(sqlite3*);
4627
4628 /*
4629 ** CAPI3REF: Find The Database Handle Of A Prepared Statement
4630 **
4631 ** ^The sqlite3_db_handle interface returns the [database connection] handle
4632 ** to which a [prepared statement] belongs. ^The [database connection]
4633 ** returned by sqlite3_db_handle is the same [database connection]
4634 ** that was the first argument
4635 ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
4636 ** create the statement in the first place.
4637 */
4638 SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
4639
4640 /*
4641 ** CAPI3REF: Return The Filename For A Database Connection
4642 **
4643 ** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename
4644 ** associated with database N of connection D. ^The main database file
4645 ** has the name "main". If there is no attached database N on the database
4646 ** connection D, or if database N is a temporary or in-memory database, then
4647 ** a NULL pointer is returned.
4648 **
4649 ** ^The filename returned by this function is the output of the
4650 ** xFullPathname method of the [VFS]. ^In other words, the filename
4651 ** will be an absolute pathname, even if the filename used
4652 ** to open the database originally was a URI or relative pathname.
4653 */
4654 SQLITE_API const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName);
4655
4656 /*
4657 ** CAPI3REF: Determine if a database is read-only
4658 **
4659 ** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N
4660 ** of connection D is read-only, 0 if it is read/write, or -1 if N is not
4661 ** the name of a database on connection D.
4662 */
4663 SQLITE_API int sqlite3_db_readonly(sqlite3 *db, const char *zDbName);
4664
4665 /*
4666 ** CAPI3REF: Find the next prepared statement
4667 **
4668 ** ^This interface returns a pointer to the next [prepared statement] after
4669 ** pStmt associated with the [database connection] pDb. ^If pStmt is NULL
4670 ** then this interface returns a pointer to the first prepared statement
4671 ** associated with the database connection pDb. ^If no prepared statement
4672 ** satisfies the conditions of this routine, it returns NULL.
4673 **
4674 ** The [database connection] pointer D in a call to
4675 ** [sqlite3_next_stmt(D,S)] must refer to an open database
4676 ** connection and in particular must not be a NULL pointer.
4677 */
4678 SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
4679
4680 /*
4681 ** CAPI3REF: Commit And Rollback Notification Callbacks
4682 **
4683 ** ^The sqlite3_commit_hook() interface registers a callback
4684 ** function to be invoked whenever a transaction is [COMMIT | committed].
4685 ** ^Any callback set by a previous call to sqlite3_commit_hook()
4686 ** for the same database connection is overridden.
4687 ** ^The sqlite3_rollback_hook() interface registers a callback
4688 ** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
4689 ** ^Any callback set by a previous call to sqlite3_rollback_hook()
4690 ** for the same database connection is overridden.
4691 ** ^The pArg argument is passed through to the callback.
4692 ** ^If the callback on a commit hook function returns non-zero,
4693 ** then the commit is converted into a rollback.
4694 **
4695 ** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
4696 ** return the P argument from the previous call of the same function
4697 ** on the same [database connection] D, or NULL for
4698 ** the first call for each function on D.
4699 **
4700 ** The commit and rollback hook callbacks are not reentrant.
4701 ** The callback implementation must not do anything that will modify
4702 ** the database connection that invoked the callback. Any actions
4703 ** to modify the database connection must be deferred until after the
4704 ** completion of the [sqlite3_step()] call that triggered the commit
4705 ** or rollback hook in the first place.
4706 ** Note that running any other SQL statements, including SELECT statements,
4707 ** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
4708 ** the database connections for the meaning of "modify" in this paragraph.
4709 **
4710 ** ^Registering a NULL function disables the callback.
4711 **
4712 ** ^When the commit hook callback routine returns zero, the [COMMIT]
4713 ** operation is allowed to continue normally. ^If the commit hook
4714 ** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
4715 ** ^The rollback hook is invoked on a rollback that results from a commit
4716 ** hook returning non-zero, just as it would be with any other rollback.
4717 **
4718 ** ^For the purposes of this API, a transaction is said to have been
4719 ** rolled back if an explicit "ROLLBACK" statement is executed, or
4720 ** an error or constraint causes an implicit rollback to occur.
4721 ** ^The rollback callback is not invoked if a transaction is
4722 ** automatically rolled back because the database connection is closed.
4723 **
4724 ** See also the [sqlite3_update_hook()] interface.
4725 */
4726 SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
4727 SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
4728
4729 /*
4730 ** CAPI3REF: Data Change Notification Callbacks
4731 **
4732 ** ^The sqlite3_update_hook() interface registers a callback function
4733 ** with the [database connection] identified by the first argument
4734 ** to be invoked whenever a row is updated, inserted or deleted.
4735 ** ^Any callback set by a previous call to this function
4736 ** for the same database connection is overridden.
4737 **
4738 ** ^The second argument is a pointer to the function to invoke when a
4739 ** row is updated, inserted or deleted.
4740 ** ^The first argument to the callback is a copy of the third argument
4741 ** to sqlite3_update_hook().
4742 ** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
4743 ** or [SQLITE_UPDATE], depending on the operation that caused the callback
4744 ** to be invoked.
4745 ** ^The third and fourth arguments to the callback contain pointers to the
4746 ** database and table name containing the affected row.
4747 ** ^The final callback parameter is the [rowid] of the row.
4748 ** ^In the case of an update, this is the [rowid] after the update takes place.
4749 **
4750 ** ^(The update hook is not invoked when internal system tables are
4751 ** modified (i.e. sqlite_master and sqlite_sequence).)^
4752 **
4753 ** ^In the current implementation, the update hook
4754 ** is not invoked when duplication rows are deleted because of an
4755 ** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook
4756 ** invoked when rows are deleted using the [truncate optimization].
4757 ** The exceptions defined in this paragraph might change in a future
4758 ** release of SQLite.
4759 **
4760 ** The update hook implementation must not do anything that will modify
4761 ** the database connection that invoked the update hook. Any actions
4762 ** to modify the database connection must be deferred until after the
4763 ** completion of the [sqlite3_step()] call that triggered the update hook.
4764 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
4765 ** database connections for the meaning of "modify" in this paragraph.
4766 **
4767 ** ^The sqlite3_update_hook(D,C,P) function
4768 ** returns the P argument from the previous call
4769 ** on the same [database connection] D, or NULL for
4770 ** the first call on D.
4771 **
4772 ** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()]
4773 ** interfaces.
4774 */
4775 SQLITE_API void *sqlite3_update_hook(
4776 sqlite3*,
4777 void(*)(void *,int ,char const *,char const *,sqlite3_int64),
4778 void*
4779 );
4780
4781 /*
4782 ** CAPI3REF: Enable Or Disable Shared Pager Cache
4783 **
4784 ** ^(This routine enables or disables the sharing of the database cache
4785 ** and schema data structures between [database connection | connections]
4786 ** to the same database. Sharing is enabled if the argument is true
4787 ** and disabled if the argument is false.)^
4788 **
4789 ** ^Cache sharing is enabled and disabled for an entire process.
4790 ** This is a change as of SQLite version 3.5.0. In prior versions of SQLite,
4791 ** sharing was enabled or disabled for each thread separately.
4792 **
4793 ** ^(The cache sharing mode set by this interface effects all subsequent
4794 ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
4795 ** Existing database connections continue use the sharing mode
4796 ** that was in effect at the time they were opened.)^
4797 **
4798 ** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
4799 ** successfully. An [error code] is returned otherwise.)^
4800 **
4801 ** ^Shared cache is disabled by default. But this might change in
4802 ** future releases of SQLite. Applications that care about shared
4803 ** cache setting should set it explicitly.
4804 **
4805 ** This interface is threadsafe on processors where writing a
4806 ** 32-bit integer is atomic.
4807 **
4808 ** See Also: [SQLite Shared-Cache Mode]
4809 */
4810 SQLITE_API int sqlite3_enable_shared_cache(int);
4811
4812 /*
4813 ** CAPI3REF: Attempt To Free Heap Memory
4814 **
4815 ** ^The sqlite3_release_memory() interface attempts to free N bytes
4816 ** of heap memory by deallocating non-essential memory allocations
4817 ** held by the database library. Memory used to cache database
4818 ** pages to improve performance is an example of non-essential memory.
4819 ** ^sqlite3_release_memory() returns the number of bytes actually freed,
4820 ** which might be more or less than the amount requested.
4821 ** ^The sqlite3_release_memory() routine is a no-op returning zero
4822 ** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
4823 **
4824 ** See also: [sqlite3_db_release_memory()]
4825 */
4826 SQLITE_API int sqlite3_release_memory(int);
4827
4828 /*
4829 ** CAPI3REF: Free Memory Used By A Database Connection
4830 **
4831 ** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap
4832 ** memory as possible from database connection D. Unlike the
4833 ** [sqlite3_release_memory()] interface, this interface is effect even
4834 ** when then [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
4835 ** omitted.
4836 **
4837 ** See also: [sqlite3_release_memory()]
4838 */
4839 SQLITE_API int sqlite3_db_release_memory(sqlite3*);
4840
4841 /*
4842 ** CAPI3REF: Impose A Limit On Heap Size
4843 **
4844 ** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
4845 ** soft limit on the amount of heap memory that may be allocated by SQLite.
4846 ** ^SQLite strives to keep heap memory utilization below the soft heap
4847 ** limit by reducing the number of pages held in the page cache
4848 ** as heap memory usages approaches the limit.
4849 ** ^The soft heap limit is "soft" because even though SQLite strives to stay
4850 ** below the limit, it will exceed the limit rather than generate
4851 ** an [SQLITE_NOMEM] error. In other words, the soft heap limit
4852 ** is advisory only.
4853 **
4854 ** ^The return value from sqlite3_soft_heap_limit64() is the size of
4855 ** the soft heap limit prior to the call, or negative in the case of an
4856 ** error. ^If the argument N is negative
4857 ** then no change is made to the soft heap limit. Hence, the current
4858 ** size of the soft heap limit can be determined by invoking
4859 ** sqlite3_soft_heap_limit64() with a negative argument.
4860 **
4861 ** ^If the argument N is zero then the soft heap limit is disabled.
4862 **
4863 ** ^(The soft heap limit is not enforced in the current implementation
4864 ** if one or more of following conditions are true:
4865 **
4866 ** <ul>
4867 ** <li> The soft heap limit is set to zero.
4868 ** <li> Memory accounting is disabled using a combination of the
4869 ** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
4870 ** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
4871 ** <li> An alternative page cache implementation is specified using
4872 ** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
4873 ** <li> The page cache allocates from its own memory pool supplied
4874 ** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
4875 ** from the heap.
4876 ** </ul>)^
4877 **
4878 ** Beginning with SQLite version 3.7.3, the soft heap limit is enforced
4879 ** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT]
4880 ** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT],
4881 ** the soft heap limit is enforced on every memory allocation. Without
4882 ** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced
4883 ** when memory is allocated by the page cache. Testing suggests that because
4884 ** the page cache is the predominate memory user in SQLite, most
4885 ** applications will achieve adequate soft heap limit enforcement without
4886 ** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT].
4887 **
4888 ** The circumstances under which SQLite will enforce the soft heap limit may
4889 ** changes in future releases of SQLite.
4890 */
4891 SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);
4892
4893 /*
4894 ** CAPI3REF: Deprecated Soft Heap Limit Interface
4895 ** DEPRECATED
4896 **
4897 ** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
4898 ** interface. This routine is provided for historical compatibility
4899 ** only. All new applications should use the
4900 ** [sqlite3_soft_heap_limit64()] interface rather than this one.
4901 */
4902 SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N);
4903
4904
4905 /*
4906 ** CAPI3REF: Extract Metadata About A Column Of A Table
4907 **
4908 ** ^This routine returns metadata about a specific column of a specific
4909 ** database table accessible using the [database connection] handle
4910 ** passed as the first function argument.
4911 **
4912 ** ^The column is identified by the second, third and fourth parameters to
4913 ** this function. ^The second parameter is either the name of the database
4914 ** (i.e. "main", "temp", or an attached database) containing the specified
4915 ** table or NULL. ^If it is NULL, then all attached databases are searched
4916 ** for the table using the same algorithm used by the database engine to
4917 ** resolve unqualified table references.
4918 **
4919 ** ^The third and fourth parameters to this function are the table and column
4920 ** name of the desired column, respectively. Neither of these parameters
4921 ** may be NULL.
4922 **
4923 ** ^Metadata is returned by writing to the memory locations passed as the 5th
4924 ** and subsequent parameters to this function. ^Any of these arguments may be
4925 ** NULL, in which case the corresponding element of metadata is omitted.
4926 **
4927 ** ^(<blockquote>
4928 ** <table border="1">
4929 ** <tr><th> Parameter <th> Output<br>Type <th> Description
4930 **
4931 ** <tr><td> 5th <td> const char* <td> Data type
4932 ** <tr><td> 6th <td> const char* <td> Name of default collation sequence
4933 ** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint
4934 ** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY
4935 ** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT]
4936 ** </table>
4937 ** </blockquote>)^
4938 **
4939 ** ^The memory pointed to by the character pointers returned for the
4940 ** declaration type and collation sequence is valid only until the next
4941 ** call to any SQLite API function.
4942 **
4943 ** ^If the specified table is actually a view, an [error code] is returned.
4944 **
4945 ** ^If the specified column is "rowid", "oid" or "_rowid_" and an
4946 ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
4947 ** parameters are set for the explicitly declared column. ^(If there is no
4948 ** explicitly declared [INTEGER PRIMARY KEY] column, then the output
4949 ** parameters are set as follows:
4950 **
4951 ** <pre>
4952 ** data type: "INTEGER"
4953 ** collation sequence: "BINARY"
4954 ** not null: 0
4955 ** primary key: 1
4956 ** auto increment: 0
4957 ** </pre>)^
4958 **
4959 ** ^(This function may load one or more schemas from database files. If an
4960 ** error occurs during this process, or if the requested table or column
4961 ** cannot be found, an [error code] is returned and an error message left
4962 ** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^
4963 **
4964 ** ^This API is only available if the library was compiled with the
4965 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined.
4966 */
4967 SQLITE_API int sqlite3_table_column_metadata(
4968 sqlite3 *db, /* Connection handle */
4969 const char *zDbName, /* Database name or NULL */
4970 const char *zTableName, /* Table name */
4971 const char *zColumnName, /* Column name */
4972 char const **pzDataType, /* OUTPUT: Declared data type */
4973 char const **pzCollSeq, /* OUTPUT: Collation sequence name */
4974 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */
4975 int *pPrimaryKey, /* OUTPUT: True if column part of PK */
4976 int *pAutoinc /* OUTPUT: True if column is auto-increment */
4977 );
4978
4979 /*
4980 ** CAPI3REF: Load An Extension
4981 **
4982 ** ^This interface loads an SQLite extension library from the named file.
4983 **
4984 ** ^The sqlite3_load_extension() interface attempts to load an
4985 ** SQLite extension library contained in the file zFile.
4986 **
4987 ** ^The entry point is zProc.
4988 ** ^zProc may be 0, in which case the name of the entry point
4989 ** defaults to "sqlite3_extension_init".
4990 ** ^The sqlite3_load_extension() interface returns
4991 ** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
4992 ** ^If an error occurs and pzErrMsg is not 0, then the
4993 ** [sqlite3_load_extension()] interface shall attempt to
4994 ** fill *pzErrMsg with error message text stored in memory
4995 ** obtained from [sqlite3_malloc()]. The calling function
4996 ** should free this memory by calling [sqlite3_free()].
4997 **
4998 ** ^Extension loading must be enabled using
4999 ** [sqlite3_enable_load_extension()] prior to calling this API,
5000 ** otherwise an error will be returned.
5001 **
5002 ** See also the [load_extension() SQL function].
5003 */
5004 SQLITE_API int sqlite3_load_extension(
5005 sqlite3 *db, /* Load the extension into this database connection */
5006 const char *zFile, /* Name of the shared library containing extension */
5007 const char *zProc, /* Entry point. Derived from zFile if 0 */
5008 char **pzErrMsg /* Put error message here if not 0 */
5009 );
5010
5011 /*
5012 ** CAPI3REF: Enable Or Disable Extension Loading
5013 **
5014 ** ^So as not to open security holes in older applications that are
5015 ** unprepared to deal with extension loading, and as a means of disabling
5016 ** extension loading while evaluating user-entered SQL, the following API
5017 ** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
5018 **
5019 ** ^Extension loading is off by default. See ticket #1863.
5020 ** ^Call the sqlite3_enable_load_extension() routine with onoff==1
5021 ** to turn extension loading on and call it with onoff==0 to turn
5022 ** it back off again.
5023 */
5024 SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
5025
5026 /*
5027 ** CAPI3REF: Automatically Load Statically Linked Extensions
5028 **
5029 ** ^This interface causes the xEntryPoint() function to be invoked for
5030 ** each new [database connection] that is created. The idea here is that
5031 ** xEntryPoint() is the entry point for a statically linked SQLite extension
5032 ** that is to be automatically loaded into all new database connections.
5033 **
5034 ** ^(Even though the function prototype shows that xEntryPoint() takes
5035 ** no arguments and returns void, SQLite invokes xEntryPoint() with three
5036 ** arguments and expects and integer result as if the signature of the
5037 ** entry point where as follows:
5038 **
5039 ** <blockquote><pre>
5040 ** &nbsp; int xEntryPoint(
5041 ** &nbsp; sqlite3 *db,
5042 ** &nbsp; const char **pzErrMsg,
5043 ** &nbsp; const struct sqlite3_api_routines *pThunk
5044 ** &nbsp; );
5045 ** </pre></blockquote>)^
5046 **
5047 ** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
5048 ** point to an appropriate error message (obtained from [sqlite3_mprintf()])
5049 ** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg
5050 ** is NULL before calling the xEntryPoint(). ^SQLite will invoke
5051 ** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any
5052 ** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
5053 ** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
5054 **
5055 ** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
5056 ** on the list of automatic extensions is a harmless no-op. ^No entry point
5057 ** will be called more than once for each database connection that is opened.
5058 **
5059 ** See also: [sqlite3_reset_auto_extension()].
5060 */
5061 SQLITE_API int sqlite3_auto_extension(void (*xEntryPoint)(void));
5062
5063 /*
5064 ** CAPI3REF: Reset Automatic Extension Loading
5065 **
5066 ** ^This interface disables all automatic extensions previously
5067 ** registered using [sqlite3_auto_extension()].
5068 */
5069 SQLITE_API void sqlite3_reset_auto_extension(void);
5070
5071 /*
5072 ** The interface to the virtual-table mechanism is currently considered
5073 ** to be experimental. The interface might change in incompatible ways.
5074 ** If this is a problem for you, do not use the interface at this time.
5075 **
5076 ** When the virtual-table mechanism stabilizes, we will declare the
5077 ** interface fixed, support it indefinitely, and remove this comment.
5078 */
5079
5080 /*
5081 ** Structures used by the virtual table interface
5082 */
5083 typedef struct sqlite3_vtab sqlite3_vtab;
5084 typedef struct sqlite3_index_info sqlite3_index_info;
5085 typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
5086 typedef struct sqlite3_module sqlite3_module;
5087
5088 /*
5089 ** CAPI3REF: Virtual Table Object
5090 ** KEYWORDS: sqlite3_module {virtual table module}
5091 **
5092 ** This structure, sometimes called a "virtual table module",
5093 ** defines the implementation of a [virtual tables].
5094 ** This structure consists mostly of methods for the module.
5095 **
5096 ** ^A virtual table module is created by filling in a persistent
5097 ** instance of this structure and passing a pointer to that instance
5098 ** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
5099 ** ^The registration remains valid until it is replaced by a different
5100 ** module or until the [database connection] closes. The content
5101 ** of this structure must not change while it is registered with
5102 ** any database connection.
5103 */
5104 struct sqlite3_module {
5105 int iVersion;
5106 int (*xCreate)(sqlite3*, void *pAux,
5107 int argc, const char *const*argv,
5108 sqlite3_vtab **ppVTab, char**);
5109 int (*xConnect)(sqlite3*, void *pAux,
5110 int argc, const char *const*argv,
5111 sqlite3_vtab **ppVTab, char**);
5112 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
5113 int (*xDisconnect)(sqlite3_vtab *pVTab);
5114 int (*xDestroy)(sqlite3_vtab *pVTab);
5115 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
5116 int (*xClose)(sqlite3_vtab_cursor*);
5117 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
5118 int argc, sqlite3_value **argv);
5119 int (*xNext)(sqlite3_vtab_cursor*);
5120 int (*xEof)(sqlite3_vtab_cursor*);
5121 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
5122 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
5123 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
5124 int (*xBegin)(sqlite3_vtab *pVTab);
5125 int (*xSync)(sqlite3_vtab *pVTab);
5126 int (*xCommit)(sqlite3_vtab *pVTab);
5127 int (*xRollback)(sqlite3_vtab *pVTab);
5128 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
5129 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
5130 void **ppArg);
5131 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
5132 /* The methods above are in version 1 of the sqlite_module object. Those
5133 ** below are for version 2 and greater. */
5134 int (*xSavepoint)(sqlite3_vtab *pVTab, int);
5135 int (*xRelease)(sqlite3_vtab *pVTab, int);
5136 int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
5137 };
5138
5139 /*
5140 ** CAPI3REF: Virtual Table Indexing Information
5141 ** KEYWORDS: sqlite3_index_info
5142 **
5143 ** The sqlite3_index_info structure and its substructures is used as part
5144 ** of the [virtual table] interface to
5145 ** pass information into and receive the reply from the [xBestIndex]
5146 ** method of a [virtual table module]. The fields under **Inputs** are the
5147 ** inputs to xBestIndex and are read-only. xBestIndex inserts its
5148 ** results into the **Outputs** fields.
5149 **
5150 ** ^(The aConstraint[] array records WHERE clause constraints of the form:
5151 **
5152 ** <blockquote>column OP expr</blockquote>
5153 **
5154 ** where OP is =, &lt;, &lt;=, &gt;, or &gt;=.)^ ^(The particular operator is
5155 ** stored in aConstraint[].op using one of the
5156 ** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
5157 ** ^(The index of the column is stored in
5158 ** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the
5159 ** expr on the right-hand side can be evaluated (and thus the constraint
5160 ** is usable) and false if it cannot.)^
5161 **
5162 ** ^The optimizer automatically inverts terms of the form "expr OP column"
5163 ** and makes other simplifications to the WHERE clause in an attempt to
5164 ** get as many WHERE clause terms into the form shown above as possible.
5165 ** ^The aConstraint[] array only reports WHERE clause terms that are
5166 ** relevant to the particular virtual table being queried.
5167 **
5168 ** ^Information about the ORDER BY clause is stored in aOrderBy[].
5169 ** ^Each term of aOrderBy records a column of the ORDER BY clause.
5170 **
5171 ** The [xBestIndex] method must fill aConstraintUsage[] with information
5172 ** about what parameters to pass to xFilter. ^If argvIndex>0 then
5173 ** the right-hand side of the corresponding aConstraint[] is evaluated
5174 ** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit
5175 ** is true, then the constraint is assumed to be fully handled by the
5176 ** virtual table and is not checked again by SQLite.)^
5177 **
5178 ** ^The idxNum and idxPtr values are recorded and passed into the
5179 ** [xFilter] method.
5180 ** ^[sqlite3_free()] is used to free idxPtr if and only if
5181 ** needToFreeIdxPtr is true.
5182 **
5183 ** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
5184 ** the correct order to satisfy the ORDER BY clause so that no separate
5185 ** sorting step is required.
5186 **
5187 ** ^The estimatedCost value is an estimate of the cost of doing the
5188 ** particular lookup. A full scan of a table with N entries should have
5189 ** a cost of N. A binary search of a table of N entries should have a
5190 ** cost of approximately log(N).
5191 */
5192 struct sqlite3_index_info {
5193 /* Inputs */
5194 int nConstraint; /* Number of entries in aConstraint */
5195 struct sqlite3_index_constraint {
5196 int iColumn; /* Column on left-hand side of constraint */
5197 unsigned char op; /* Constraint operator */
5198 unsigned char usable; /* True if this constraint is usable */
5199 int iTermOffset; /* Used internally - xBestIndex should ignore */
5200 } *aConstraint; /* Table of WHERE clause constraints */
5201 int nOrderBy; /* Number of terms in the ORDER BY clause */
5202 struct sqlite3_index_orderby {
5203 int iColumn; /* Column number */
5204 unsigned char desc; /* True for DESC. False for ASC. */
5205 } *aOrderBy; /* The ORDER BY clause */
5206 /* Outputs */
5207 struct sqlite3_index_constraint_usage {
5208 int argvIndex; /* if >0, constraint is part of argv to xFilter */
5209 unsigned char omit; /* Do not code a test for this constraint */
5210 } *aConstraintUsage;
5211 int idxNum; /* Number used to identify the index */
5212 char *idxStr; /* String, possibly obtained from sqlite3_malloc */
5213 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */
5214 int orderByConsumed; /* True if output is already ordered */
5215 double estimatedCost; /* Estimated cost of using this index */
5216 };
5217
5218 /*
5219 ** CAPI3REF: Virtual Table Constraint Operator Codes
5220 **
5221 ** These macros defined the allowed values for the
5222 ** [sqlite3_index_info].aConstraint[].op field. Each value represents
5223 ** an operator that is part of a constraint term in the wHERE clause of
5224 ** a query that uses a [virtual table].
5225 */
5226 #define SQLITE_INDEX_CONSTRAINT_EQ 2
5227 #define SQLITE_INDEX_CONSTRAINT_GT 4
5228 #define SQLITE_INDEX_CONSTRAINT_LE 8
5229 #define SQLITE_INDEX_CONSTRAINT_LT 16
5230 #define SQLITE_INDEX_CONSTRAINT_GE 32
5231 #define SQLITE_INDEX_CONSTRAINT_MATCH 64
5232
5233 /*
5234 ** CAPI3REF: Register A Virtual Table Implementation
5235 **
5236 ** ^These routines are used to register a new [virtual table module] name.
5237 ** ^Module names must be registered before
5238 ** creating a new [virtual table] using the module and before using a
5239 ** preexisting [virtual table] for the module.
5240 **
5241 ** ^The module name is registered on the [database connection] specified
5242 ** by the first parameter. ^The name of the module is given by the
5243 ** second parameter. ^The third parameter is a pointer to
5244 ** the implementation of the [virtual table module]. ^The fourth
5245 ** parameter is an arbitrary client data pointer that is passed through
5246 ** into the [xCreate] and [xConnect] methods of the virtual table module
5247 ** when a new virtual table is be being created or reinitialized.
5248 **
5249 ** ^The sqlite3_create_module_v2() interface has a fifth parameter which
5250 ** is a pointer to a destructor for the pClientData. ^SQLite will
5251 ** invoke the destructor function (if it is not NULL) when SQLite
5252 ** no longer needs the pClientData pointer. ^The destructor will also
5253 ** be invoked if the call to sqlite3_create_module_v2() fails.
5254 ** ^The sqlite3_create_module()
5255 ** interface is equivalent to sqlite3_create_module_v2() with a NULL
5256 ** destructor.
5257 */
5258 SQLITE_API int sqlite3_create_module(
5259 sqlite3 *db, /* SQLite connection to register module with */
5260 const char *zName, /* Name of the module */
5261 const sqlite3_module *p, /* Methods for the module */
5262 void *pClientData /* Client data for xCreate/xConnect */
5263 );
5264 SQLITE_API int sqlite3_create_module_v2(
5265 sqlite3 *db, /* SQLite connection to register module with */
5266 const char *zName, /* Name of the module */
5267 const sqlite3_module *p, /* Methods for the module */
5268 void *pClientData, /* Client data for xCreate/xConnect */
5269 void(*xDestroy)(void*) /* Module destructor function */
5270 );
5271
5272 /*
5273 ** CAPI3REF: Virtual Table Instance Object
5274 ** KEYWORDS: sqlite3_vtab
5275 **
5276 ** Every [virtual table module] implementation uses a subclass
5277 ** of this object to describe a particular instance
5278 ** of the [virtual table]. Each subclass will
5279 ** be tailored to the specific needs of the module implementation.
5280 ** The purpose of this superclass is to define certain fields that are
5281 ** common to all module implementations.
5282 **
5283 ** ^Virtual tables methods can set an error message by assigning a
5284 ** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should
5285 ** take care that any prior string is freed by a call to [sqlite3_free()]
5286 ** prior to assigning a new string to zErrMsg. ^After the error message
5287 ** is delivered up to the client application, the string will be automatically
5288 ** freed by sqlite3_free() and the zErrMsg field will be zeroed.
5289 */
5290 struct sqlite3_vtab {
5291 const sqlite3_module *pModule; /* The module for this virtual table */
5292 int nRef; /* NO LONGER USED */
5293 char *zErrMsg; /* Error message from sqlite3_mprintf() */
5294 /* Virtual table implementations will typically add additional fields */
5295 };
5296
5297 /*
5298 ** CAPI3REF: Virtual Table Cursor Object
5299 ** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
5300 **
5301 ** Every [virtual table module] implementation uses a subclass of the
5302 ** following structure to describe cursors that point into the
5303 ** [virtual table] and are used
5304 ** to loop through the virtual table. Cursors are created using the
5305 ** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
5306 ** by the [sqlite3_module.xClose | xClose] method. Cursors are used
5307 ** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
5308 ** of the module. Each module implementation will define
5309 ** the content of a cursor structure to suit its own needs.
5310 **
5311 ** This superclass exists in order to define fields of the cursor that
5312 ** are common to all implementations.
5313 */
5314 struct sqlite3_vtab_cursor {
5315 sqlite3_vtab *pVtab; /* Virtual table of this cursor */
5316 /* Virtual table implementations will typically add additional fields */
5317 };
5318
5319 /*
5320 ** CAPI3REF: Declare The Schema Of A Virtual Table
5321 **
5322 ** ^The [xCreate] and [xConnect] methods of a
5323 ** [virtual table module] call this interface
5324 ** to declare the format (the names and datatypes of the columns) of
5325 ** the virtual tables they implement.
5326 */
5327 SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
5328
5329 /*
5330 ** CAPI3REF: Overload A Function For A Virtual Table
5331 **
5332 ** ^(Virtual tables can provide alternative implementations of functions
5333 ** using the [xFindFunction] method of the [virtual table module].
5334 ** But global versions of those functions
5335 ** must exist in order to be overloaded.)^
5336 **
5337 ** ^(This API makes sure a global version of a function with a particular
5338 ** name and number of parameters exists. If no such function exists
5339 ** before this API is called, a new function is created.)^ ^The implementation
5340 ** of the new function always causes an exception to be thrown. So
5341 ** the new function is not good for anything by itself. Its only
5342 ** purpose is to be a placeholder function that can be overloaded
5343 ** by a [virtual table].
5344 */
5345 SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
5346
5347 /*
5348 ** The interface to the virtual-table mechanism defined above (back up
5349 ** to a comment remarkably similar to this one) is currently considered
5350 ** to be experimental. The interface might change in incompatible ways.
5351 ** If this is a problem for you, do not use the interface at this time.
5352 **
5353 ** When the virtual-table mechanism stabilizes, we will declare the
5354 ** interface fixed, support it indefinitely, and remove this comment.
5355 */
5356
5357 /*
5358 ** CAPI3REF: A Handle To An Open BLOB
5359 ** KEYWORDS: {BLOB handle} {BLOB handles}
5360 **
5361 ** An instance of this object represents an open BLOB on which
5362 ** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
5363 ** ^Objects of this type are created by [sqlite3_blob_open()]
5364 ** and destroyed by [sqlite3_blob_close()].
5365 ** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
5366 ** can be used to read or write small subsections of the BLOB.
5367 ** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
5368 */
5369 typedef struct sqlite3_blob sqlite3_blob;
5370
5371 /*
5372 ** CAPI3REF: Open A BLOB For Incremental I/O
5373 **
5374 ** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
5375 ** in row iRow, column zColumn, table zTable in database zDb;
5376 ** in other words, the same BLOB that would be selected by:
5377 **
5378 ** <pre>
5379 ** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
5380 ** </pre>)^
5381 **
5382 ** ^If the flags parameter is non-zero, then the BLOB is opened for read
5383 ** and write access. ^If it is zero, the BLOB is opened for read access.
5384 ** ^It is not possible to open a column that is part of an index or primary
5385 ** key for writing. ^If [foreign key constraints] are enabled, it is
5386 ** not possible to open a column that is part of a [child key] for writing.
5387 **
5388 ** ^Note that the database name is not the filename that contains
5389 ** the database but rather the symbolic name of the database that
5390 ** appears after the AS keyword when the database is connected using [ATTACH].
5391 ** ^For the main database file, the database name is "main".
5392 ** ^For TEMP tables, the database name is "temp".
5393 **
5394 ** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written
5395 ** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set
5396 ** to be a null pointer.)^
5397 ** ^This function sets the [database connection] error code and message
5398 ** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related
5399 ** functions. ^Note that the *ppBlob variable is always initialized in a
5400 ** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob
5401 ** regardless of the success or failure of this routine.
5402 **
5403 ** ^(If the row that a BLOB handle points to is modified by an
5404 ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
5405 ** then the BLOB handle is marked as "expired".
5406 ** This is true if any column of the row is changed, even a column
5407 ** other than the one the BLOB handle is open on.)^
5408 ** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
5409 ** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
5410 ** ^(Changes written into a BLOB prior to the BLOB expiring are not
5411 ** rolled back by the expiration of the BLOB. Such changes will eventually
5412 ** commit if the transaction continues to completion.)^
5413 **
5414 ** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
5415 ** the opened blob. ^The size of a blob may not be changed by this
5416 ** interface. Use the [UPDATE] SQL command to change the size of a
5417 ** blob.
5418 **
5419 ** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
5420 ** and the built-in [zeroblob] SQL function can be used, if desired,
5421 ** to create an empty, zero-filled blob in which to read or write using
5422 ** this interface.
5423 **
5424 ** To avoid a resource leak, every open [BLOB handle] should eventually
5425 ** be released by a call to [sqlite3_blob_close()].
5426 */
5427 SQLITE_API int sqlite3_blob_open(
5428 sqlite3*,
5429 const char *zDb,
5430 const char *zTable,
5431 const char *zColumn,
5432 sqlite3_int64 iRow,
5433 int flags,
5434 sqlite3_blob **ppBlob
5435 );
5436
5437 /*
5438 ** CAPI3REF: Move a BLOB Handle to a New Row
5439 **
5440 ** ^This function is used to move an existing blob handle so that it points
5441 ** to a different row of the same database table. ^The new row is identified
5442 ** by the rowid value passed as the second argument. Only the row can be
5443 ** changed. ^The database, table and column on which the blob handle is open
5444 ** remain the same. Moving an existing blob handle to a new row can be
5445 ** faster than closing the existing handle and opening a new one.
5446 **
5447 ** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
5448 ** it must exist and there must be either a blob or text value stored in
5449 ** the nominated column.)^ ^If the new row is not present in the table, or if
5450 ** it does not contain a blob or text value, or if another error occurs, an
5451 ** SQLite error code is returned and the blob handle is considered aborted.
5452 ** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
5453 ** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
5454 ** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
5455 ** always returns zero.
5456 **
5457 ** ^This function sets the database handle error code and message.
5458 */
5459 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
5460
5461 /*
5462 ** CAPI3REF: Close A BLOB Handle
5463 **
5464 ** ^Closes an open [BLOB handle].
5465 **
5466 ** ^Closing a BLOB shall cause the current transaction to commit
5467 ** if there are no other BLOBs, no pending prepared statements, and the
5468 ** database connection is in [autocommit mode].
5469 ** ^If any writes were made to the BLOB, they might be held in cache
5470 ** until the close operation if they will fit.
5471 **
5472 ** ^(Closing the BLOB often forces the changes
5473 ** out to disk and so if any I/O errors occur, they will likely occur
5474 ** at the time when the BLOB is closed. Any errors that occur during
5475 ** closing are reported as a non-zero return value.)^
5476 **
5477 ** ^(The BLOB is closed unconditionally. Even if this routine returns
5478 ** an error code, the BLOB is still closed.)^
5479 **
5480 ** ^Calling this routine with a null pointer (such as would be returned
5481 ** by a failed call to [sqlite3_blob_open()]) is a harmless no-op.
5482 */
5483 SQLITE_API int sqlite3_blob_close(sqlite3_blob *);
5484
5485 /*
5486 ** CAPI3REF: Return The Size Of An Open BLOB
5487 **
5488 ** ^Returns the size in bytes of the BLOB accessible via the
5489 ** successfully opened [BLOB handle] in its only argument. ^The
5490 ** incremental blob I/O routines can only read or overwriting existing
5491 ** blob content; they cannot change the size of a blob.
5492 **
5493 ** This routine only works on a [BLOB handle] which has been created
5494 ** by a prior successful call to [sqlite3_blob_open()] and which has not
5495 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
5496 ** to this routine results in undefined and probably undesirable behavior.
5497 */
5498 SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *);
5499
5500 /*
5501 ** CAPI3REF: Read Data From A BLOB Incrementally
5502 **
5503 ** ^(This function is used to read data from an open [BLOB handle] into a
5504 ** caller-supplied buffer. N bytes of data are copied into buffer Z
5505 ** from the open BLOB, starting at offset iOffset.)^
5506 **
5507 ** ^If offset iOffset is less than N bytes from the end of the BLOB,
5508 ** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is
5509 ** less than zero, [SQLITE_ERROR] is returned and no data is read.
5510 ** ^The size of the blob (and hence the maximum value of N+iOffset)
5511 ** can be determined using the [sqlite3_blob_bytes()] interface.
5512 **
5513 ** ^An attempt to read from an expired [BLOB handle] fails with an
5514 ** error code of [SQLITE_ABORT].
5515 **
5516 ** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
5517 ** Otherwise, an [error code] or an [extended error code] is returned.)^
5518 **
5519 ** This routine only works on a [BLOB handle] which has been created
5520 ** by a prior successful call to [sqlite3_blob_open()] and which has not
5521 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
5522 ** to this routine results in undefined and probably undesirable behavior.
5523 **
5524 ** See also: [sqlite3_blob_write()].
5525 */
5526 SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
5527
5528 /*
5529 ** CAPI3REF: Write Data Into A BLOB Incrementally
5530 **
5531 ** ^This function is used to write data into an open [BLOB handle] from a
5532 ** caller-supplied buffer. ^N bytes of data are copied from the buffer Z
5533 ** into the open BLOB, starting at offset iOffset.
5534 **
5535 ** ^If the [BLOB handle] passed as the first argument was not opened for
5536 ** writing (the flags parameter to [sqlite3_blob_open()] was zero),
5537 ** this function returns [SQLITE_READONLY].
5538 **
5539 ** ^This function may only modify the contents of the BLOB; it is
5540 ** not possible to increase the size of a BLOB using this API.
5541 ** ^If offset iOffset is less than N bytes from the end of the BLOB,
5542 ** [SQLITE_ERROR] is returned and no data is written. ^If N is
5543 ** less than zero [SQLITE_ERROR] is returned and no data is written.
5544 ** The size of the BLOB (and hence the maximum value of N+iOffset)
5545 ** can be determined using the [sqlite3_blob_bytes()] interface.
5546 **
5547 ** ^An attempt to write to an expired [BLOB handle] fails with an
5548 ** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred
5549 ** before the [BLOB handle] expired are not rolled back by the
5550 ** expiration of the handle, though of course those changes might
5551 ** have been overwritten by the statement that expired the BLOB handle
5552 ** or by other independent statements.
5553 **
5554 ** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
5555 ** Otherwise, an [error code] or an [extended error code] is returned.)^
5556 **
5557 ** This routine only works on a [BLOB handle] which has been created
5558 ** by a prior successful call to [sqlite3_blob_open()] and which has not
5559 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
5560 ** to this routine results in undefined and probably undesirable behavior.
5561 **
5562 ** See also: [sqlite3_blob_read()].
5563 */
5564 SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
5565
5566 /*
5567 ** CAPI3REF: Virtual File System Objects
5568 **
5569 ** A virtual filesystem (VFS) is an [sqlite3_vfs] object
5570 ** that SQLite uses to interact
5571 ** with the underlying operating system. Most SQLite builds come with a
5572 ** single default VFS that is appropriate for the host computer.
5573 ** New VFSes can be registered and existing VFSes can be unregistered.
5574 ** The following interfaces are provided.
5575 **
5576 ** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
5577 ** ^Names are case sensitive.
5578 ** ^Names are zero-terminated UTF-8 strings.
5579 ** ^If there is no match, a NULL pointer is returned.
5580 ** ^If zVfsName is NULL then the default VFS is returned.
5581 **
5582 ** ^New VFSes are registered with sqlite3_vfs_register().
5583 ** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
5584 ** ^The same VFS can be registered multiple times without injury.
5585 ** ^To make an existing VFS into the default VFS, register it again
5586 ** with the makeDflt flag set. If two different VFSes with the
5587 ** same name are registered, the behavior is undefined. If a
5588 ** VFS is registered with a name that is NULL or an empty string,
5589 ** then the behavior is undefined.
5590 **
5591 ** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
5592 ** ^(If the default VFS is unregistered, another VFS is chosen as
5593 ** the default. The choice for the new VFS is arbitrary.)^
5594 */
5595 SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
5596 SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
5597 SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*);
5598
5599 /*
5600 ** CAPI3REF: Mutexes
5601 **
5602 ** The SQLite core uses these routines for thread
5603 ** synchronization. Though they are intended for internal
5604 ** use by SQLite, code that links against SQLite is
5605 ** permitted to use any of these routines.
5606 **
5607 ** The SQLite source code contains multiple implementations
5608 ** of these mutex routines. An appropriate implementation
5609 ** is selected automatically at compile-time. ^(The following
5610 ** implementations are available in the SQLite core:
5611 **
5612 ** <ul>
5613 ** <li> SQLITE_MUTEX_PTHREADS
5614 ** <li> SQLITE_MUTEX_W32
5615 ** <li> SQLITE_MUTEX_NOOP
5616 ** </ul>)^
5617 **
5618 ** ^The SQLITE_MUTEX_NOOP implementation is a set of routines
5619 ** that does no real locking and is appropriate for use in
5620 ** a single-threaded application. ^The SQLITE_MUTEX_PTHREADS and
5621 ** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
5622 ** and Windows.
5623 **
5624 ** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
5625 ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
5626 ** implementation is included with the library. In this case the
5627 ** application must supply a custom mutex implementation using the
5628 ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
5629 ** before calling sqlite3_initialize() or any other public sqlite3_
5630 ** function that calls sqlite3_initialize().)^
5631 **
5632 ** ^The sqlite3_mutex_alloc() routine allocates a new
5633 ** mutex and returns a pointer to it. ^If it returns NULL
5634 ** that means that a mutex could not be allocated. ^SQLite
5635 ** will unwind its stack and return an error. ^(The argument
5636 ** to sqlite3_mutex_alloc() is one of these integer constants:
5637 **
5638 ** <ul>
5639 ** <li> SQLITE_MUTEX_FAST
5640 ** <li> SQLITE_MUTEX_RECURSIVE
5641 ** <li> SQLITE_MUTEX_STATIC_MASTER
5642 ** <li> SQLITE_MUTEX_STATIC_MEM
5643 ** <li> SQLITE_MUTEX_STATIC_MEM2
5644 ** <li> SQLITE_MUTEX_STATIC_PRNG
5645 ** <li> SQLITE_MUTEX_STATIC_LRU
5646 ** <li> SQLITE_MUTEX_STATIC_LRU2
5647 ** </ul>)^
5648 **
5649 ** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
5650 ** cause sqlite3_mutex_alloc() to create
5651 ** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
5652 ** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
5653 ** The mutex implementation does not need to make a distinction
5654 ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
5655 ** not want to. ^SQLite will only request a recursive mutex in
5656 ** cases where it really needs one. ^If a faster non-recursive mutex
5657 ** implementation is available on the host platform, the mutex subsystem
5658 ** might return such a mutex in response to SQLITE_MUTEX_FAST.
5659 **
5660 ** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
5661 ** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
5662 ** a pointer to a static preexisting mutex. ^Six static mutexes are
5663 ** used by the current version of SQLite. Future versions of SQLite
5664 ** may add additional static mutexes. Static mutexes are for internal
5665 ** use by SQLite only. Applications that use SQLite mutexes should
5666 ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
5667 ** SQLITE_MUTEX_RECURSIVE.
5668 **
5669 ** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
5670 ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
5671 ** returns a different mutex on every call. ^But for the static
5672 ** mutex types, the same mutex is returned on every call that has
5673 ** the same type number.
5674 **
5675 ** ^The sqlite3_mutex_free() routine deallocates a previously
5676 ** allocated dynamic mutex. ^SQLite is careful to deallocate every
5677 ** dynamic mutex that it allocates. The dynamic mutexes must not be in
5678 ** use when they are deallocated. Attempting to deallocate a static
5679 ** mutex results in undefined behavior. ^SQLite never deallocates
5680 ** a static mutex.
5681 **
5682 ** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
5683 ** to enter a mutex. ^If another thread is already within the mutex,
5684 ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
5685 ** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
5686 ** upon successful entry. ^(Mutexes created using
5687 ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
5688 ** In such cases the,
5689 ** mutex must be exited an equal number of times before another thread
5690 ** can enter.)^ ^(If the same thread tries to enter any other
5691 ** kind of mutex more than once, the behavior is undefined.
5692 ** SQLite will never exhibit
5693 ** such behavior in its own use of mutexes.)^
5694 **
5695 ** ^(Some systems (for example, Windows 95) do not support the operation
5696 ** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try()
5697 ** will always return SQLITE_BUSY. The SQLite core only ever uses
5698 ** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^
5699 **
5700 ** ^The sqlite3_mutex_leave() routine exits a mutex that was
5701 ** previously entered by the same thread. ^(The behavior
5702 ** is undefined if the mutex is not currently entered by the
5703 ** calling thread or is not currently allocated. SQLite will
5704 ** never do either.)^
5705 **
5706 ** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
5707 ** sqlite3_mutex_leave() is a NULL pointer, then all three routines
5708 ** behave as no-ops.
5709 **
5710 ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
5711 */
5712 SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int);
5713 SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*);
5714 SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*);
5715 SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*);
5716 SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*);
5717
5718 /*
5719 ** CAPI3REF: Mutex Methods Object
5720 **
5721 ** An instance of this structure defines the low-level routines
5722 ** used to allocate and use mutexes.
5723 **
5724 ** Usually, the default mutex implementations provided by SQLite are
5725 ** sufficient, however the user has the option of substituting a custom
5726 ** implementation for specialized deployments or systems for which SQLite
5727 ** does not provide a suitable implementation. In this case, the user
5728 ** creates and populates an instance of this structure to pass
5729 ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
5730 ** Additionally, an instance of this structure can be used as an
5731 ** output variable when querying the system for the current mutex
5732 ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
5733 **
5734 ** ^The xMutexInit method defined by this structure is invoked as
5735 ** part of system initialization by the sqlite3_initialize() function.
5736 ** ^The xMutexInit routine is called by SQLite exactly once for each
5737 ** effective call to [sqlite3_initialize()].
5738 **
5739 ** ^The xMutexEnd method defined by this structure is invoked as
5740 ** part of system shutdown by the sqlite3_shutdown() function. The
5741 ** implementation of this method is expected to release all outstanding
5742 ** resources obtained by the mutex methods implementation, especially
5743 ** those obtained by the xMutexInit method. ^The xMutexEnd()
5744 ** interface is invoked exactly once for each call to [sqlite3_shutdown()].
5745 **
5746 ** ^(The remaining seven methods defined by this structure (xMutexAlloc,
5747 ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
5748 ** xMutexNotheld) implement the following interfaces (respectively):
5749 **
5750 ** <ul>
5751 ** <li> [sqlite3_mutex_alloc()] </li>
5752 ** <li> [sqlite3_mutex_free()] </li>
5753 ** <li> [sqlite3_mutex_enter()] </li>
5754 ** <li> [sqlite3_mutex_try()] </li>
5755 ** <li> [sqlite3_mutex_leave()] </li>
5756 ** <li> [sqlite3_mutex_held()] </li>
5757 ** <li> [sqlite3_mutex_notheld()] </li>
5758 ** </ul>)^
5759 **
5760 ** The only difference is that the public sqlite3_XXX functions enumerated
5761 ** above silently ignore any invocations that pass a NULL pointer instead
5762 ** of a valid mutex handle. The implementations of the methods defined
5763 ** by this structure are not required to handle this case, the results
5764 ** of passing a NULL pointer instead of a valid mutex handle are undefined
5765 ** (i.e. it is acceptable to provide an implementation that segfaults if
5766 ** it is passed a NULL pointer).
5767 **
5768 ** The xMutexInit() method must be threadsafe. ^It must be harmless to
5769 ** invoke xMutexInit() multiple times within the same process and without
5770 ** intervening calls to xMutexEnd(). Second and subsequent calls to
5771 ** xMutexInit() must be no-ops.
5772 **
5773 ** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
5774 ** and its associates). ^Similarly, xMutexAlloc() must not use SQLite memory
5775 ** allocation for a static mutex. ^However xMutexAlloc() may use SQLite
5776 ** memory allocation for a fast or recursive mutex.
5777 **
5778 ** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
5779 ** called, but only if the prior call to xMutexInit returned SQLITE_OK.
5780 ** If xMutexInit fails in any way, it is expected to clean up after itself
5781 ** prior to returning.
5782 */
5783 typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
5784 struct sqlite3_mutex_methods {
5785 int (*xMutexInit)(void);
5786 int (*xMutexEnd)(void);
5787 sqlite3_mutex *(*xMutexAlloc)(int);
5788 void (*xMutexFree)(sqlite3_mutex *);
5789 void (*xMutexEnter)(sqlite3_mutex *);
5790 int (*xMutexTry)(sqlite3_mutex *);
5791 void (*xMutexLeave)(sqlite3_mutex *);
5792 int (*xMutexHeld)(sqlite3_mutex *);
5793 int (*xMutexNotheld)(sqlite3_mutex *);
5794 };
5795
5796 /*
5797 ** CAPI3REF: Mutex Verification Routines
5798 **
5799 ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
5800 ** are intended for use inside assert() statements. ^The SQLite core
5801 ** never uses these routines except inside an assert() and applications
5802 ** are advised to follow the lead of the core. ^The SQLite core only
5803 ** provides implementations for these routines when it is compiled
5804 ** with the SQLITE_DEBUG flag. ^External mutex implementations
5805 ** are only required to provide these routines if SQLITE_DEBUG is
5806 ** defined and if NDEBUG is not defined.
5807 **
5808 ** ^These routines should return true if the mutex in their argument
5809 ** is held or not held, respectively, by the calling thread.
5810 **
5811 ** ^The implementation is not required to provide versions of these
5812 ** routines that actually work. If the implementation does not provide working
5813 ** versions of these routines, it should at least provide stubs that always
5814 ** return true so that one does not get spurious assertion failures.
5815 **
5816 ** ^If the argument to sqlite3_mutex_held() is a NULL pointer then
5817 ** the routine should return 1. This seems counter-intuitive since
5818 ** clearly the mutex cannot be held if it does not exist. But
5819 ** the reason the mutex does not exist is because the build is not
5820 ** using mutexes. And we do not want the assert() containing the
5821 ** call to sqlite3_mutex_held() to fail, so a non-zero return is
5822 ** the appropriate thing to do. ^The sqlite3_mutex_notheld()
5823 ** interface should also return 1 when given a NULL pointer.
5824 */
5825 #ifndef NDEBUG
5826 SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*);
5827 SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*);
5828 #endif
5829
5830 /*
5831 ** CAPI3REF: Mutex Types
5832 **
5833 ** The [sqlite3_mutex_alloc()] interface takes a single argument
5834 ** which is one of these integer constants.
5835 **
5836 ** The set of static mutexes may change from one SQLite release to the
5837 ** next. Applications that override the built-in mutex logic must be
5838 ** prepared to accommodate additional static mutexes.
5839 */
5840 #define SQLITE_MUTEX_FAST 0
5841 #define SQLITE_MUTEX_RECURSIVE 1
5842 #define SQLITE_MUTEX_STATIC_MASTER 2
5843 #define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */
5844 #define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */
5845 #define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */
5846 #define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */
5847 #define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */
5848 #define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */
5849 #define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */
5850
5851 /*
5852 ** CAPI3REF: Retrieve the mutex for a database connection
5853 **
5854 ** ^This interface returns a pointer the [sqlite3_mutex] object that
5855 ** serializes access to the [database connection] given in the argument
5856 ** when the [threading mode] is Serialized.
5857 ** ^If the [threading mode] is Single-thread or Multi-thread then this
5858 ** routine returns a NULL pointer.
5859 */
5860 SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
5861
5862 /*
5863 ** CAPI3REF: Low-Level Control Of Database Files
5864 **
5865 ** ^The [sqlite3_file_control()] interface makes a direct call to the
5866 ** xFileControl method for the [sqlite3_io_methods] object associated
5867 ** with a particular database identified by the second argument. ^The
5868 ** name of the database is "main" for the main database or "temp" for the
5869 ** TEMP database, or the name that appears after the AS keyword for
5870 ** databases that are added using the [ATTACH] SQL command.
5871 ** ^A NULL pointer can be used in place of "main" to refer to the
5872 ** main database file.
5873 ** ^The third and fourth parameters to this routine
5874 ** are passed directly through to the second and third parameters of
5875 ** the xFileControl method. ^The return value of the xFileControl
5876 ** method becomes the return value of this routine.
5877 **
5878 ** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes
5879 ** a pointer to the underlying [sqlite3_file] object to be written into
5880 ** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER
5881 ** case is a short-circuit path which does not actually invoke the
5882 ** underlying sqlite3_io_methods.xFileControl method.
5883 **
5884 ** ^If the second parameter (zDbName) does not match the name of any
5885 ** open database file, then SQLITE_ERROR is returned. ^This error
5886 ** code is not remembered and will not be recalled by [sqlite3_errcode()]
5887 ** or [sqlite3_errmsg()]. The underlying xFileControl method might
5888 ** also return SQLITE_ERROR. There is no way to distinguish between
5889 ** an incorrect zDbName and an SQLITE_ERROR return from the underlying
5890 ** xFileControl method.
5891 **
5892 ** See also: [SQLITE_FCNTL_LOCKSTATE]
5893 */
5894 SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
5895
5896 /*
5897 ** CAPI3REF: Testing Interface
5898 **
5899 ** ^The sqlite3_test_control() interface is used to read out internal
5900 ** state of SQLite and to inject faults into SQLite for testing
5901 ** purposes. ^The first parameter is an operation code that determines
5902 ** the number, meaning, and operation of all subsequent parameters.
5903 **
5904 ** This interface is not for use by applications. It exists solely
5905 ** for verifying the correct operation of the SQLite library. Depending
5906 ** on how the SQLite library is compiled, this interface might not exist.
5907 **
5908 ** The details of the operation codes, their meanings, the parameters
5909 ** they take, and what they do are all subject to change without notice.
5910 ** Unlike most of the SQLite API, this function is not guaranteed to
5911 ** operate consistently from one release to the next.
5912 */
5913 SQLITE_API int sqlite3_test_control(int op, ...);
5914
5915 /*
5916 ** CAPI3REF: Testing Interface Operation Codes
5917 **
5918 ** These constants are the valid operation code parameters used
5919 ** as the first argument to [sqlite3_test_control()].
5920 **
5921 ** These parameters and their meanings are subject to change
5922 ** without notice. These values are for testing purposes only.
5923 ** Applications should not use any of these parameters or the
5924 ** [sqlite3_test_control()] interface.
5925 */
5926 #define SQLITE_TESTCTRL_FIRST 5
5927 #define SQLITE_TESTCTRL_PRNG_SAVE 5
5928 #define SQLITE_TESTCTRL_PRNG_RESTORE 6
5929 #define SQLITE_TESTCTRL_PRNG_RESET 7
5930 #define SQLITE_TESTCTRL_BITVEC_TEST 8
5931 #define SQLITE_TESTCTRL_FAULT_INSTALL 9
5932 #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10
5933 #define SQLITE_TESTCTRL_PENDING_BYTE 11
5934 #define SQLITE_TESTCTRL_ASSERT 12
5935 #define SQLITE_TESTCTRL_ALWAYS 13
5936 #define SQLITE_TESTCTRL_RESERVE 14
5937 #define SQLITE_TESTCTRL_OPTIMIZATIONS 15
5938 #define SQLITE_TESTCTRL_ISKEYWORD 16
5939 #define SQLITE_TESTCTRL_SCRATCHMALLOC 17
5940 #define SQLITE_TESTCTRL_LOCALTIME_FAULT 18
5941 #define SQLITE_TESTCTRL_EXPLAIN_STMT 19
5942 #define SQLITE_TESTCTRL_LAST 19
5943
5944 /*
5945 ** CAPI3REF: SQLite Runtime Status
5946 **
5947 ** ^This interface is used to retrieve runtime status information
5948 ** about the performance of SQLite, and optionally to reset various
5949 ** highwater marks. ^The first argument is an integer code for
5950 ** the specific parameter to measure. ^(Recognized integer codes
5951 ** are of the form [status parameters | SQLITE_STATUS_...].)^
5952 ** ^The current value of the parameter is returned into *pCurrent.
5953 ** ^The highest recorded value is returned in *pHighwater. ^If the
5954 ** resetFlag is true, then the highest record value is reset after
5955 ** *pHighwater is written. ^(Some parameters do not record the highest
5956 ** value. For those parameters
5957 ** nothing is written into *pHighwater and the resetFlag is ignored.)^
5958 ** ^(Other parameters record only the highwater mark and not the current
5959 ** value. For these latter parameters nothing is written into *pCurrent.)^
5960 **
5961 ** ^The sqlite3_status() routine returns SQLITE_OK on success and a
5962 ** non-zero [error code] on failure.
5963 **
5964 ** This routine is threadsafe but is not atomic. This routine can be
5965 ** called while other threads are running the same or different SQLite
5966 ** interfaces. However the values returned in *pCurrent and
5967 ** *pHighwater reflect the status of SQLite at different points in time
5968 ** and it is possible that another thread might change the parameter
5969 ** in between the times when *pCurrent and *pHighwater are written.
5970 **
5971 ** See also: [sqlite3_db_status()]
5972 */
5973 SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
5974
5975
5976 /*
5977 ** CAPI3REF: Status Parameters
5978 ** KEYWORDS: {status parameters}
5979 **
5980 ** These integer constants designate various run-time status parameters
5981 ** that can be returned by [sqlite3_status()].
5982 **
5983 ** <dl>
5984 ** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
5985 ** <dd>This parameter is the current amount of memory checked out
5986 ** using [sqlite3_malloc()], either directly or indirectly. The
5987 ** figure includes calls made to [sqlite3_malloc()] by the application
5988 ** and internal memory usage by the SQLite library. Scratch memory
5989 ** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache
5990 ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
5991 ** this parameter. The amount returned is the sum of the allocation
5992 ** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
5993 **
5994 ** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
5995 ** <dd>This parameter records the largest memory allocation request
5996 ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
5997 ** internal equivalents). Only the value returned in the
5998 ** *pHighwater parameter to [sqlite3_status()] is of interest.
5999 ** The value written into the *pCurrent parameter is undefined.</dd>)^
6000 **
6001 ** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
6002 ** <dd>This parameter records the number of separate memory allocations
6003 ** currently checked out.</dd>)^
6004 **
6005 ** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
6006 ** <dd>This parameter returns the number of pages used out of the
6007 ** [pagecache memory allocator] that was configured using
6008 ** [SQLITE_CONFIG_PAGECACHE]. The
6009 ** value returned is in pages, not in bytes.</dd>)^
6010 **
6011 ** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]]
6012 ** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
6013 ** <dd>This parameter returns the number of bytes of page cache
6014 ** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
6015 ** buffer and where forced to overflow to [sqlite3_malloc()]. The
6016 ** returned value includes allocations that overflowed because they
6017 ** where too large (they were larger than the "sz" parameter to
6018 ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
6019 ** no space was left in the page cache.</dd>)^
6020 **
6021 ** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
6022 ** <dd>This parameter records the largest memory allocation request
6023 ** handed to [pagecache memory allocator]. Only the value returned in the
6024 ** *pHighwater parameter to [sqlite3_status()] is of interest.
6025 ** The value written into the *pCurrent parameter is undefined.</dd>)^
6026 **
6027 ** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt>
6028 ** <dd>This parameter returns the number of allocations used out of the
6029 ** [scratch memory allocator] configured using
6030 ** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not
6031 ** in bytes. Since a single thread may only have one scratch allocation
6032 ** outstanding at time, this parameter also reports the number of threads
6033 ** using scratch memory at the same time.</dd>)^
6034 **
6035 ** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
6036 ** <dd>This parameter returns the number of bytes of scratch memory
6037 ** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH]
6038 ** buffer and where forced to overflow to [sqlite3_malloc()]. The values
6039 ** returned include overflows because the requested allocation was too
6040 ** larger (that is, because the requested allocation was larger than the
6041 ** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer
6042 ** slots were available.
6043 ** </dd>)^
6044 **
6045 ** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
6046 ** <dd>This parameter records the largest memory allocation request
6047 ** handed to [scratch memory allocator]. Only the value returned in the
6048 ** *pHighwater parameter to [sqlite3_status()] is of interest.
6049 ** The value written into the *pCurrent parameter is undefined.</dd>)^
6050 **
6051 ** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
6052 ** <dd>This parameter records the deepest parser stack. It is only
6053 ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
6054 ** </dl>
6055 **
6056 ** New status parameters may be added from time to time.
6057 */
6058 #define SQLITE_STATUS_MEMORY_USED 0
6059 #define SQLITE_STATUS_PAGECACHE_USED 1
6060 #define SQLITE_STATUS_PAGECACHE_OVERFLOW 2
6061 #define SQLITE_STATUS_SCRATCH_USED 3
6062 #define SQLITE_STATUS_SCRATCH_OVERFLOW 4
6063 #define SQLITE_STATUS_MALLOC_SIZE 5
6064 #define SQLITE_STATUS_PARSER_STACK 6
6065 #define SQLITE_STATUS_PAGECACHE_SIZE 7
6066 #define SQLITE_STATUS_SCRATCH_SIZE 8
6067 #define SQLITE_STATUS_MALLOC_COUNT 9
6068
6069 /*
6070 ** CAPI3REF: Database Connection Status
6071 **
6072 ** ^This interface is used to retrieve runtime status information
6073 ** about a single [database connection]. ^The first argument is the
6074 ** database connection object to be interrogated. ^The second argument
6075 ** is an integer constant, taken from the set of
6076 ** [SQLITE_DBSTATUS options], that
6077 ** determines the parameter to interrogate. The set of
6078 ** [SQLITE_DBSTATUS options] is likely
6079 ** to grow in future releases of SQLite.
6080 **
6081 ** ^The current value of the requested parameter is written into *pCur
6082 ** and the highest instantaneous value is written into *pHiwtr. ^If
6083 ** the resetFlg is true, then the highest instantaneous value is
6084 ** reset back down to the current value.
6085 **
6086 ** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
6087 ** non-zero [error code] on failure.
6088 **
6089 ** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
6090 */
6091 SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
6092
6093 /*
6094 ** CAPI3REF: Status Parameters for database connections
6095 ** KEYWORDS: {SQLITE_DBSTATUS options}
6096 **
6097 ** These constants are the available integer "verbs" that can be passed as
6098 ** the second argument to the [sqlite3_db_status()] interface.
6099 **
6100 ** New verbs may be added in future releases of SQLite. Existing verbs
6101 ** might be discontinued. Applications should check the return code from
6102 ** [sqlite3_db_status()] to make sure that the call worked.
6103 ** The [sqlite3_db_status()] interface will return a non-zero error code
6104 ** if a discontinued or unsupported verb is invoked.
6105 **
6106 ** <dl>
6107 ** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
6108 ** <dd>This parameter returns the number of lookaside memory slots currently
6109 ** checked out.</dd>)^
6110 **
6111 ** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
6112 ** <dd>This parameter returns the number malloc attempts that were
6113 ** satisfied using lookaside memory. Only the high-water value is meaningful;
6114 ** the current value is always zero.)^
6115 **
6116 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]]
6117 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
6118 ** <dd>This parameter returns the number malloc attempts that might have
6119 ** been satisfied using lookaside memory but failed due to the amount of
6120 ** memory requested being larger than the lookaside slot size.
6121 ** Only the high-water value is meaningful;
6122 ** the current value is always zero.)^
6123 **
6124 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]]
6125 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
6126 ** <dd>This parameter returns the number malloc attempts that might have
6127 ** been satisfied using lookaside memory but failed due to all lookaside
6128 ** memory already being in use.
6129 ** Only the high-water value is meaningful;
6130 ** the current value is always zero.)^
6131 **
6132 ** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
6133 ** <dd>This parameter returns the approximate number of of bytes of heap
6134 ** memory used by all pager caches associated with the database connection.)^
6135 ** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
6136 **
6137 ** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
6138 ** <dd>This parameter returns the approximate number of of bytes of heap
6139 ** memory used to store the schema for all databases associated
6140 ** with the connection - main, temp, and any [ATTACH]-ed databases.)^
6141 ** ^The full amount of memory used by the schemas is reported, even if the
6142 ** schema memory is shared with other database connections due to
6143 ** [shared cache mode] being enabled.
6144 ** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
6145 **
6146 ** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
6147 ** <dd>This parameter returns the approximate number of of bytes of heap
6148 ** and lookaside memory used by all prepared statements associated with
6149 ** the database connection.)^
6150 ** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
6151 ** </dd>
6152 **
6153 ** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt>
6154 ** <dd>This parameter returns the number of pager cache hits that have
6155 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT
6156 ** is always 0.
6157 ** </dd>
6158 **
6159 ** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt>
6160 ** <dd>This parameter returns the number of pager cache misses that have
6161 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS
6162 ** is always 0.
6163 ** </dd>
6164 **
6165 ** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt>
6166 ** <dd>This parameter returns the number of dirty cache entries that have
6167 ** been written to disk. Specifically, the number of pages written to the
6168 ** wal file in wal mode databases, or the number of pages written to the
6169 ** database file in rollback mode databases. Any pages written as part of
6170 ** transaction rollback or database recovery operations are not included.
6171 ** If an IO or other error occurs while writing a page to disk, the effect
6172 ** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The
6173 ** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0.
6174 ** </dd>
6175 ** </dl>
6176 */
6177 #define SQLITE_DBSTATUS_LOOKASIDE_USED 0
6178 #define SQLITE_DBSTATUS_CACHE_USED 1
6179 #define SQLITE_DBSTATUS_SCHEMA_USED 2
6180 #define SQLITE_DBSTATUS_STMT_USED 3
6181 #define SQLITE_DBSTATUS_LOOKASIDE_HIT 4
6182 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5
6183 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6
6184 #define SQLITE_DBSTATUS_CACHE_HIT 7
6185 #define SQLITE_DBSTATUS_CACHE_MISS 8
6186 #define SQLITE_DBSTATUS_CACHE_WRITE 9
6187 #define SQLITE_DBSTATUS_MAX 9 /* Largest defined DBSTATUS */
6188
6189
6190 /*
6191 ** CAPI3REF: Prepared Statement Status
6192 **
6193 ** ^(Each prepared statement maintains various
6194 ** [SQLITE_STMTSTATUS counters] that measure the number
6195 ** of times it has performed specific operations.)^ These counters can
6196 ** be used to monitor the performance characteristics of the prepared
6197 ** statements. For example, if the number of table steps greatly exceeds
6198 ** the number of table searches or result rows, that would tend to indicate
6199 ** that the prepared statement is using a full table scan rather than
6200 ** an index.
6201 **
6202 ** ^(This interface is used to retrieve and reset counter values from
6203 ** a [prepared statement]. The first argument is the prepared statement
6204 ** object to be interrogated. The second argument
6205 ** is an integer code for a specific [SQLITE_STMTSTATUS counter]
6206 ** to be interrogated.)^
6207 ** ^The current value of the requested counter is returned.
6208 ** ^If the resetFlg is true, then the counter is reset to zero after this
6209 ** interface call returns.
6210 **
6211 ** See also: [sqlite3_status()] and [sqlite3_db_status()].
6212 */
6213 SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
6214
6215 /*
6216 ** CAPI3REF: Status Parameters for prepared statements
6217 ** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters}
6218 **
6219 ** These preprocessor macros define integer codes that name counter
6220 ** values associated with the [sqlite3_stmt_status()] interface.
6221 ** The meanings of the various counters are as follows:
6222 **
6223 ** <dl>
6224 ** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
6225 ** <dd>^This is the number of times that SQLite has stepped forward in
6226 ** a table as part of a full table scan. Large numbers for this counter
6227 ** may indicate opportunities for performance improvement through
6228 ** careful use of indices.</dd>
6229 **
6230 ** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt>
6231 ** <dd>^This is the number of sort operations that have occurred.
6232 ** A non-zero value in this counter may indicate an opportunity to
6233 ** improvement performance through careful use of indices.</dd>
6234 **
6235 ** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
6236 ** <dd>^This is the number of rows inserted into transient indices that
6237 ** were created automatically in order to help joins run faster.
6238 ** A non-zero value in this counter may indicate an opportunity to
6239 ** improvement performance by adding permanent indices that do not
6240 ** need to be reinitialized each time the statement is run.</dd>
6241 ** </dl>
6242 */
6243 #define SQLITE_STMTSTATUS_FULLSCAN_STEP 1
6244 #define SQLITE_STMTSTATUS_SORT 2
6245 #define SQLITE_STMTSTATUS_AUTOINDEX 3
6246
6247 /*
6248 ** CAPI3REF: Custom Page Cache Object
6249 **
6250 ** The sqlite3_pcache type is opaque. It is implemented by
6251 ** the pluggable module. The SQLite core has no knowledge of
6252 ** its size or internal structure and never deals with the
6253 ** sqlite3_pcache object except by holding and passing pointers
6254 ** to the object.
6255 **
6256 ** See [sqlite3_pcache_methods2] for additional information.
6257 */
6258 typedef struct sqlite3_pcache sqlite3_pcache;
6259
6260 /*
6261 ** CAPI3REF: Custom Page Cache Object
6262 **
6263 ** The sqlite3_pcache_page object represents a single page in the
6264 ** page cache. The page cache will allocate instances of this
6265 ** object. Various methods of the page cache use pointers to instances
6266 ** of this object as parameters or as their return value.
6267 **
6268 ** See [sqlite3_pcache_methods2] for additional information.
6269 */
6270 typedef struct sqlite3_pcache_page sqlite3_pcache_page;
6271 struct sqlite3_pcache_page {
6272 void *pBuf; /* The content of the page */
6273 void *pExtra; /* Extra information associated with the page */
6274 };
6275
6276 /*
6277 ** CAPI3REF: Application Defined Page Cache.
6278 ** KEYWORDS: {page cache}
6279 **
6280 ** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can
6281 ** register an alternative page cache implementation by passing in an
6282 ** instance of the sqlite3_pcache_methods2 structure.)^
6283 ** In many applications, most of the heap memory allocated by
6284 ** SQLite is used for the page cache.
6285 ** By implementing a
6286 ** custom page cache using this API, an application can better control
6287 ** the amount of memory consumed by SQLite, the way in which
6288 ** that memory is allocated and released, and the policies used to
6289 ** determine exactly which parts of a database file are cached and for
6290 ** how long.
6291 **
6292 ** The alternative page cache mechanism is an
6293 ** extreme measure that is only needed by the most demanding applications.
6294 ** The built-in page cache is recommended for most uses.
6295 **
6296 ** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an
6297 ** internal buffer by SQLite within the call to [sqlite3_config]. Hence
6298 ** the application may discard the parameter after the call to
6299 ** [sqlite3_config()] returns.)^
6300 **
6301 ** [[the xInit() page cache method]]
6302 ** ^(The xInit() method is called once for each effective
6303 ** call to [sqlite3_initialize()])^
6304 ** (usually only once during the lifetime of the process). ^(The xInit()
6305 ** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^
6306 ** The intent of the xInit() method is to set up global data structures
6307 ** required by the custom page cache implementation.
6308 ** ^(If the xInit() method is NULL, then the
6309 ** built-in default page cache is used instead of the application defined
6310 ** page cache.)^
6311 **
6312 ** [[the xShutdown() page cache method]]
6313 ** ^The xShutdown() method is called by [sqlite3_shutdown()].
6314 ** It can be used to clean up
6315 ** any outstanding resources before process shutdown, if required.
6316 ** ^The xShutdown() method may be NULL.
6317 **
6318 ** ^SQLite automatically serializes calls to the xInit method,
6319 ** so the xInit method need not be threadsafe. ^The
6320 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
6321 ** not need to be threadsafe either. All other methods must be threadsafe
6322 ** in multithreaded applications.
6323 **
6324 ** ^SQLite will never invoke xInit() more than once without an intervening
6325 ** call to xShutdown().
6326 **
6327 ** [[the xCreate() page cache methods]]
6328 ** ^SQLite invokes the xCreate() method to construct a new cache instance.
6329 ** SQLite will typically create one cache instance for each open database file,
6330 ** though this is not guaranteed. ^The
6331 ** first parameter, szPage, is the size in bytes of the pages that must
6332 ** be allocated by the cache. ^szPage will always a power of two. ^The
6333 ** second parameter szExtra is a number of bytes of extra storage
6334 ** associated with each page cache entry. ^The szExtra parameter will
6335 ** a number less than 250. SQLite will use the
6336 ** extra szExtra bytes on each page to store metadata about the underlying
6337 ** database page on disk. The value passed into szExtra depends
6338 ** on the SQLite version, the target platform, and how SQLite was compiled.
6339 ** ^The third argument to xCreate(), bPurgeable, is true if the cache being
6340 ** created will be used to cache database pages of a file stored on disk, or
6341 ** false if it is used for an in-memory database. The cache implementation
6342 ** does not have to do anything special based with the value of bPurgeable;
6343 ** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will
6344 ** never invoke xUnpin() except to deliberately delete a page.
6345 ** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
6346 ** false will always have the "discard" flag set to true.
6347 ** ^Hence, a cache created with bPurgeable false will
6348 ** never contain any unpinned pages.
6349 **
6350 ** [[the xCachesize() page cache method]]
6351 ** ^(The xCachesize() method may be called at any time by SQLite to set the
6352 ** suggested maximum cache-size (number of pages stored by) the cache
6353 ** instance passed as the first argument. This is the value configured using
6354 ** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable
6355 ** parameter, the implementation is not required to do anything with this
6356 ** value; it is advisory only.
6357 **
6358 ** [[the xPagecount() page cache methods]]
6359 ** The xPagecount() method must return the number of pages currently
6360 ** stored in the cache, both pinned and unpinned.
6361 **
6362 ** [[the xFetch() page cache methods]]
6363 ** The xFetch() method locates a page in the cache and returns a pointer to
6364 ** an sqlite3_pcache_page object associated with that page, or a NULL pointer.
6365 ** The pBuf element of the returned sqlite3_pcache_page object will be a
6366 ** pointer to a buffer of szPage bytes used to store the content of a
6367 ** single database page. The pExtra element of sqlite3_pcache_page will be
6368 ** a pointer to the szExtra bytes of extra storage that SQLite has requested
6369 ** for each entry in the page cache.
6370 **
6371 ** The page to be fetched is determined by the key. ^The minimum key value
6372 ** is 1. After it has been retrieved using xFetch, the page is considered
6373 ** to be "pinned".
6374 **
6375 ** If the requested page is already in the page cache, then the page cache
6376 ** implementation must return a pointer to the page buffer with its content
6377 ** intact. If the requested page is not already in the cache, then the
6378 ** cache implementation should use the value of the createFlag
6379 ** parameter to help it determined what action to take:
6380 **
6381 ** <table border=1 width=85% align=center>
6382 ** <tr><th> createFlag <th> Behaviour when page is not already in cache
6383 ** <tr><td> 0 <td> Do not allocate a new page. Return NULL.
6384 ** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
6385 ** Otherwise return NULL.
6386 ** <tr><td> 2 <td> Make every effort to allocate a new page. Only return
6387 ** NULL if allocating a new page is effectively impossible.
6388 ** </table>
6389 **
6390 ** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite
6391 ** will only use a createFlag of 2 after a prior call with a createFlag of 1
6392 ** failed.)^ In between the to xFetch() calls, SQLite may
6393 ** attempt to unpin one or more cache pages by spilling the content of
6394 ** pinned pages to disk and synching the operating system disk cache.
6395 **
6396 ** [[the xUnpin() page cache method]]
6397 ** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
6398 ** as its second argument. If the third parameter, discard, is non-zero,
6399 ** then the page must be evicted from the cache.
6400 ** ^If the discard parameter is
6401 ** zero, then the page may be discarded or retained at the discretion of
6402 ** page cache implementation. ^The page cache implementation
6403 ** may choose to evict unpinned pages at any time.
6404 **
6405 ** The cache must not perform any reference counting. A single
6406 ** call to xUnpin() unpins the page regardless of the number of prior calls
6407 ** to xFetch().
6408 **
6409 ** [[the xRekey() page cache methods]]
6410 ** The xRekey() method is used to change the key value associated with the
6411 ** page passed as the second argument. If the cache
6412 ** previously contains an entry associated with newKey, it must be
6413 ** discarded. ^Any prior cache entry associated with newKey is guaranteed not
6414 ** to be pinned.
6415 **
6416 ** When SQLite calls the xTruncate() method, the cache must discard all
6417 ** existing cache entries with page numbers (keys) greater than or equal
6418 ** to the value of the iLimit parameter passed to xTruncate(). If any
6419 ** of these pages are pinned, they are implicitly unpinned, meaning that
6420 ** they can be safely discarded.
6421 **
6422 ** [[the xDestroy() page cache method]]
6423 ** ^The xDestroy() method is used to delete a cache allocated by xCreate().
6424 ** All resources associated with the specified cache should be freed. ^After
6425 ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
6426 ** handle invalid, and will not use it with any other sqlite3_pcache_methods2
6427 ** functions.
6428 **
6429 ** [[the xShrink() page cache method]]
6430 ** ^SQLite invokes the xShrink() method when it wants the page cache to
6431 ** free up as much of heap memory as possible. The page cache implementation
6432 ** is not obligated to free any memory, but well-behaved implementations should
6433 ** do their best.
6434 */
6435 typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
6436 struct sqlite3_pcache_methods2 {
6437 int iVersion;
6438 void *pArg;
6439 int (*xInit)(void*);
6440 void (*xShutdown)(void*);
6441 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
6442 void (*xCachesize)(sqlite3_pcache*, int nCachesize);
6443 int (*xPagecount)(sqlite3_pcache*);
6444 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
6445 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
6446 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*,
6447 unsigned oldKey, unsigned newKey);
6448 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
6449 void (*xDestroy)(sqlite3_pcache*);
6450 void (*xShrink)(sqlite3_pcache*);
6451 };
6452
6453 /*
6454 ** This is the obsolete pcache_methods object that has now been replaced
6455 ** by sqlite3_pcache_methods2. This object is not used by SQLite. It is
6456 ** retained in the header file for backwards compatibility only.
6457 */
6458 typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
6459 struct sqlite3_pcache_methods {
6460 void *pArg;
6461 int (*xInit)(void*);
6462 void (*xShutdown)(void*);
6463 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
6464 void (*xCachesize)(sqlite3_pcache*, int nCachesize);
6465 int (*xPagecount)(sqlite3_pcache*);
6466 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
6467 void (*xUnpin)(sqlite3_pcache*, void*, int discard);
6468 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
6469 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
6470 void (*xDestroy)(sqlite3_pcache*);
6471 };
6472
6473
6474 /*
6475 ** CAPI3REF: Online Backup Object
6476 **
6477 ** The sqlite3_backup object records state information about an ongoing
6478 ** online backup operation. ^The sqlite3_backup object is created by
6479 ** a call to [sqlite3_backup_init()] and is destroyed by a call to
6480 ** [sqlite3_backup_finish()].
6481 **
6482 ** See Also: [Using the SQLite Online Backup API]
6483 */
6484 typedef struct sqlite3_backup sqlite3_backup;
6485
6486 /*
6487 ** CAPI3REF: Online Backup API.
6488 **
6489 ** The backup API copies the content of one database into another.
6490 ** It is useful either for creating backups of databases or
6491 ** for copying in-memory databases to or from persistent files.
6492 **
6493 ** See Also: [Using the SQLite Online Backup API]
6494 **
6495 ** ^SQLite holds a write transaction open on the destination database file
6496 ** for the duration of the backup operation.
6497 ** ^The source database is read-locked only while it is being read;
6498 ** it is not locked continuously for the entire backup operation.
6499 ** ^Thus, the backup may be performed on a live source database without
6500 ** preventing other database connections from
6501 ** reading or writing to the source database while the backup is underway.
6502 **
6503 ** ^(To perform a backup operation:
6504 ** <ol>
6505 ** <li><b>sqlite3_backup_init()</b> is called once to initialize the
6506 ** backup,
6507 ** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
6508 ** the data between the two databases, and finally
6509 ** <li><b>sqlite3_backup_finish()</b> is called to release all resources
6510 ** associated with the backup operation.
6511 ** </ol>)^
6512 ** There should be exactly one call to sqlite3_backup_finish() for each
6513 ** successful call to sqlite3_backup_init().
6514 **
6515 ** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
6516 **
6517 ** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
6518 ** [database connection] associated with the destination database
6519 ** and the database name, respectively.
6520 ** ^The database name is "main" for the main database, "temp" for the
6521 ** temporary database, or the name specified after the AS keyword in
6522 ** an [ATTACH] statement for an attached database.
6523 ** ^The S and M arguments passed to
6524 ** sqlite3_backup_init(D,N,S,M) identify the [database connection]
6525 ** and database name of the source database, respectively.
6526 ** ^The source and destination [database connections] (parameters S and D)
6527 ** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
6528 ** an error.
6529 **
6530 ** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
6531 ** returned and an error code and error message are stored in the
6532 ** destination [database connection] D.
6533 ** ^The error code and message for the failed call to sqlite3_backup_init()
6534 ** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
6535 ** [sqlite3_errmsg16()] functions.
6536 ** ^A successful call to sqlite3_backup_init() returns a pointer to an
6537 ** [sqlite3_backup] object.
6538 ** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
6539 ** sqlite3_backup_finish() functions to perform the specified backup
6540 ** operation.
6541 **
6542 ** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
6543 **
6544 ** ^Function sqlite3_backup_step(B,N) will copy up to N pages between
6545 ** the source and destination databases specified by [sqlite3_backup] object B.
6546 ** ^If N is negative, all remaining source pages are copied.
6547 ** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
6548 ** are still more pages to be copied, then the function returns [SQLITE_OK].
6549 ** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
6550 ** from source to destination, then it returns [SQLITE_DONE].
6551 ** ^If an error occurs while running sqlite3_backup_step(B,N),
6552 ** then an [error code] is returned. ^As well as [SQLITE_OK] and
6553 ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
6554 ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
6555 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
6556 **
6557 ** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
6558 ** <ol>
6559 ** <li> the destination database was opened read-only, or
6560 ** <li> the destination database is using write-ahead-log journaling
6561 ** and the destination and source page sizes differ, or
6562 ** <li> the destination database is an in-memory database and the
6563 ** destination and source page sizes differ.
6564 ** </ol>)^
6565 **
6566 ** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
6567 ** the [sqlite3_busy_handler | busy-handler function]
6568 ** is invoked (if one is specified). ^If the
6569 ** busy-handler returns non-zero before the lock is available, then
6570 ** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
6571 ** sqlite3_backup_step() can be retried later. ^If the source
6572 ** [database connection]
6573 ** is being used to write to the source database when sqlite3_backup_step()
6574 ** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
6575 ** case the call to sqlite3_backup_step() can be retried later on. ^(If
6576 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
6577 ** [SQLITE_READONLY] is returned, then
6578 ** there is no point in retrying the call to sqlite3_backup_step(). These
6579 ** errors are considered fatal.)^ The application must accept
6580 ** that the backup operation has failed and pass the backup operation handle
6581 ** to the sqlite3_backup_finish() to release associated resources.
6582 **
6583 ** ^The first call to sqlite3_backup_step() obtains an exclusive lock
6584 ** on the destination file. ^The exclusive lock is not released until either
6585 ** sqlite3_backup_finish() is called or the backup operation is complete
6586 ** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to
6587 ** sqlite3_backup_step() obtains a [shared lock] on the source database that
6588 ** lasts for the duration of the sqlite3_backup_step() call.
6589 ** ^Because the source database is not locked between calls to
6590 ** sqlite3_backup_step(), the source database may be modified mid-way
6591 ** through the backup process. ^If the source database is modified by an
6592 ** external process or via a database connection other than the one being
6593 ** used by the backup operation, then the backup will be automatically
6594 ** restarted by the next call to sqlite3_backup_step(). ^If the source
6595 ** database is modified by the using the same database connection as is used
6596 ** by the backup operation, then the backup database is automatically
6597 ** updated at the same time.
6598 **
6599 ** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
6600 **
6601 ** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the
6602 ** application wishes to abandon the backup operation, the application
6603 ** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
6604 ** ^The sqlite3_backup_finish() interfaces releases all
6605 ** resources associated with the [sqlite3_backup] object.
6606 ** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
6607 ** active write-transaction on the destination database is rolled back.
6608 ** The [sqlite3_backup] object is invalid
6609 ** and may not be used following a call to sqlite3_backup_finish().
6610 **
6611 ** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
6612 ** sqlite3_backup_step() errors occurred, regardless or whether or not
6613 ** sqlite3_backup_step() completed.
6614 ** ^If an out-of-memory condition or IO error occurred during any prior
6615 ** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
6616 ** sqlite3_backup_finish() returns the corresponding [error code].
6617 **
6618 ** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
6619 ** is not a permanent error and does not affect the return value of
6620 ** sqlite3_backup_finish().
6621 **
6622 ** [[sqlite3_backup__remaining()]] [[sqlite3_backup_pagecount()]]
6623 ** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
6624 **
6625 ** ^Each call to sqlite3_backup_step() sets two values inside
6626 ** the [sqlite3_backup] object: the number of pages still to be backed
6627 ** up and the total number of pages in the source database file.
6628 ** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces
6629 ** retrieve these two values, respectively.
6630 **
6631 ** ^The values returned by these functions are only updated by
6632 ** sqlite3_backup_step(). ^If the source database is modified during a backup
6633 ** operation, then the values are not updated to account for any extra
6634 ** pages that need to be updated or the size of the source database file
6635 ** changing.
6636 **
6637 ** <b>Concurrent Usage of Database Handles</b>
6638 **
6639 ** ^The source [database connection] may be used by the application for other
6640 ** purposes while a backup operation is underway or being initialized.
6641 ** ^If SQLite is compiled and configured to support threadsafe database
6642 ** connections, then the source database connection may be used concurrently
6643 ** from within other threads.
6644 **
6645 ** However, the application must guarantee that the destination
6646 ** [database connection] is not passed to any other API (by any thread) after
6647 ** sqlite3_backup_init() is called and before the corresponding call to
6648 ** sqlite3_backup_finish(). SQLite does not currently check to see
6649 ** if the application incorrectly accesses the destination [database connection]
6650 ** and so no error code is reported, but the operations may malfunction
6651 ** nevertheless. Use of the destination database connection while a
6652 ** backup is in progress might also also cause a mutex deadlock.
6653 **
6654 ** If running in [shared cache mode], the application must
6655 ** guarantee that the shared cache used by the destination database
6656 ** is not accessed while the backup is running. In practice this means
6657 ** that the application must guarantee that the disk file being
6658 ** backed up to is not accessed by any connection within the process,
6659 ** not just the specific connection that was passed to sqlite3_backup_init().
6660 **
6661 ** The [sqlite3_backup] object itself is partially threadsafe. Multiple
6662 ** threads may safely make multiple concurrent calls to sqlite3_backup_step().
6663 ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
6664 ** APIs are not strictly speaking threadsafe. If they are invoked at the
6665 ** same time as another thread is invoking sqlite3_backup_step() it is
6666 ** possible that they return invalid values.
6667 */
6668 SQLITE_API sqlite3_backup *sqlite3_backup_init(
6669 sqlite3 *pDest, /* Destination database handle */
6670 const char *zDestName, /* Destination database name */
6671 sqlite3 *pSource, /* Source database handle */
6672 const char *zSourceName /* Source database name */
6673 );
6674 SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage);
6675 SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p);
6676 SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p);
6677 SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p);
6678
6679 /*
6680 ** CAPI3REF: Unlock Notification
6681 **
6682 ** ^When running in shared-cache mode, a database operation may fail with
6683 ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
6684 ** individual tables within the shared-cache cannot be obtained. See
6685 ** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
6686 ** ^This API may be used to register a callback that SQLite will invoke
6687 ** when the connection currently holding the required lock relinquishes it.
6688 ** ^This API is only available if the library was compiled with the
6689 ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
6690 **
6691 ** See Also: [Using the SQLite Unlock Notification Feature].
6692 **
6693 ** ^Shared-cache locks are released when a database connection concludes
6694 ** its current transaction, either by committing it or rolling it back.
6695 **
6696 ** ^When a connection (known as the blocked connection) fails to obtain a
6697 ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
6698 ** identity of the database connection (the blocking connection) that
6699 ** has locked the required resource is stored internally. ^After an
6700 ** application receives an SQLITE_LOCKED error, it may call the
6701 ** sqlite3_unlock_notify() method with the blocked connection handle as
6702 ** the first argument to register for a callback that will be invoked
6703 ** when the blocking connections current transaction is concluded. ^The
6704 ** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
6705 ** call that concludes the blocking connections transaction.
6706 **
6707 ** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
6708 ** there is a chance that the blocking connection will have already
6709 ** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
6710 ** If this happens, then the specified callback is invoked immediately,
6711 ** from within the call to sqlite3_unlock_notify().)^
6712 **
6713 ** ^If the blocked connection is attempting to obtain a write-lock on a
6714 ** shared-cache table, and more than one other connection currently holds
6715 ** a read-lock on the same table, then SQLite arbitrarily selects one of
6716 ** the other connections to use as the blocking connection.
6717 **
6718 ** ^(There may be at most one unlock-notify callback registered by a
6719 ** blocked connection. If sqlite3_unlock_notify() is called when the
6720 ** blocked connection already has a registered unlock-notify callback,
6721 ** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
6722 ** called with a NULL pointer as its second argument, then any existing
6723 ** unlock-notify callback is canceled. ^The blocked connections
6724 ** unlock-notify callback may also be canceled by closing the blocked
6725 ** connection using [sqlite3_close()].
6726 **
6727 ** The unlock-notify callback is not reentrant. If an application invokes
6728 ** any sqlite3_xxx API functions from within an unlock-notify callback, a
6729 ** crash or deadlock may be the result.
6730 **
6731 ** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
6732 ** returns SQLITE_OK.
6733 **
6734 ** <b>Callback Invocation Details</b>
6735 **
6736 ** When an unlock-notify callback is registered, the application provides a
6737 ** single void* pointer that is passed to the callback when it is invoked.
6738 ** However, the signature of the callback function allows SQLite to pass
6739 ** it an array of void* context pointers. The first argument passed to
6740 ** an unlock-notify callback is a pointer to an array of void* pointers,
6741 ** and the second is the number of entries in the array.
6742 **
6743 ** When a blocking connections transaction is concluded, there may be
6744 ** more than one blocked connection that has registered for an unlock-notify
6745 ** callback. ^If two or more such blocked connections have specified the
6746 ** same callback function, then instead of invoking the callback function
6747 ** multiple times, it is invoked once with the set of void* context pointers
6748 ** specified by the blocked connections bundled together into an array.
6749 ** This gives the application an opportunity to prioritize any actions
6750 ** related to the set of unblocked database connections.
6751 **
6752 ** <b>Deadlock Detection</b>
6753 **
6754 ** Assuming that after registering for an unlock-notify callback a
6755 ** database waits for the callback to be issued before taking any further
6756 ** action (a reasonable assumption), then using this API may cause the
6757 ** application to deadlock. For example, if connection X is waiting for
6758 ** connection Y's transaction to be concluded, and similarly connection
6759 ** Y is waiting on connection X's transaction, then neither connection
6760 ** will proceed and the system may remain deadlocked indefinitely.
6761 **
6762 ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
6763 ** detection. ^If a given call to sqlite3_unlock_notify() would put the
6764 ** system in a deadlocked state, then SQLITE_LOCKED is returned and no
6765 ** unlock-notify callback is registered. The system is said to be in
6766 ** a deadlocked state if connection A has registered for an unlock-notify
6767 ** callback on the conclusion of connection B's transaction, and connection
6768 ** B has itself registered for an unlock-notify callback when connection
6769 ** A's transaction is concluded. ^Indirect deadlock is also detected, so
6770 ** the system is also considered to be deadlocked if connection B has
6771 ** registered for an unlock-notify callback on the conclusion of connection
6772 ** C's transaction, where connection C is waiting on connection A. ^Any
6773 ** number of levels of indirection are allowed.
6774 **
6775 ** <b>The "DROP TABLE" Exception</b>
6776 **
6777 ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost
6778 ** always appropriate to call sqlite3_unlock_notify(). There is however,
6779 ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
6780 ** SQLite checks if there are any currently executing SELECT statements
6781 ** that belong to the same connection. If there are, SQLITE_LOCKED is
6782 ** returned. In this case there is no "blocking connection", so invoking
6783 ** sqlite3_unlock_notify() results in the unlock-notify callback being
6784 ** invoked immediately. If the application then re-attempts the "DROP TABLE"
6785 ** or "DROP INDEX" query, an infinite loop might be the result.
6786 **
6787 ** One way around this problem is to check the extended error code returned
6788 ** by an sqlite3_step() call. ^(If there is a blocking connection, then the
6789 ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
6790 ** the special "DROP TABLE/INDEX" case, the extended error code is just
6791 ** SQLITE_LOCKED.)^
6792 */
6793 SQLITE_API int sqlite3_unlock_notify(
6794 sqlite3 *pBlocked, /* Waiting connection */
6795 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */
6796 void *pNotifyArg /* Argument to pass to xNotify */
6797 );
6798
6799
6800 /*
6801 ** CAPI3REF: String Comparison
6802 **
6803 ** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications
6804 ** and extensions to compare the contents of two buffers containing UTF-8
6805 ** strings in a case-independent fashion, using the same definition of "case
6806 ** independence" that SQLite uses internally when comparing identifiers.
6807 */
6808 SQLITE_API int sqlite3_stricmp(const char *, const char *);
6809 SQLITE_API int sqlite3_strnicmp(const char *, const char *, int);
6810
6811 /*
6812 ** CAPI3REF: Error Logging Interface
6813 **
6814 ** ^The [sqlite3_log()] interface writes a message into the error log
6815 ** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
6816 ** ^If logging is enabled, the zFormat string and subsequent arguments are
6817 ** used with [sqlite3_snprintf()] to generate the final output string.
6818 **
6819 ** The sqlite3_log() interface is intended for use by extensions such as
6820 ** virtual tables, collating functions, and SQL functions. While there is
6821 ** nothing to prevent an application from calling sqlite3_log(), doing so
6822 ** is considered bad form.
6823 **
6824 ** The zFormat string must not be NULL.
6825 **
6826 ** To avoid deadlocks and other threading problems, the sqlite3_log() routine
6827 ** will not use dynamically allocated memory. The log message is stored in
6828 ** a fixed-length buffer on the stack. If the log message is longer than
6829 ** a few hundred characters, it will be truncated to the length of the
6830 ** buffer.
6831 */
6832 SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...);
6833
6834 /*
6835 ** CAPI3REF: Write-Ahead Log Commit Hook
6836 **
6837 ** ^The [sqlite3_wal_hook()] function is used to register a callback that
6838 ** will be invoked each time a database connection commits data to a
6839 ** [write-ahead log] (i.e. whenever a transaction is committed in
6840 ** [journal_mode | journal_mode=WAL mode]).
6841 **
6842 ** ^The callback is invoked by SQLite after the commit has taken place and
6843 ** the associated write-lock on the database released, so the implementation
6844 ** may read, write or [checkpoint] the database as required.
6845 **
6846 ** ^The first parameter passed to the callback function when it is invoked
6847 ** is a copy of the third parameter passed to sqlite3_wal_hook() when
6848 ** registering the callback. ^The second is a copy of the database handle.
6849 ** ^The third parameter is the name of the database that was written to -
6850 ** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
6851 ** is the number of pages currently in the write-ahead log file,
6852 ** including those that were just committed.
6853 **
6854 ** The callback function should normally return [SQLITE_OK]. ^If an error
6855 ** code is returned, that error will propagate back up through the
6856 ** SQLite code base to cause the statement that provoked the callback
6857 ** to report an error, though the commit will have still occurred. If the
6858 ** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
6859 ** that does not correspond to any valid SQLite error code, the results
6860 ** are undefined.
6861 **
6862 ** A single database handle may have at most a single write-ahead log callback
6863 ** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
6864 ** previously registered write-ahead log callback. ^Note that the
6865 ** [sqlite3_wal_autocheckpoint()] interface and the
6866 ** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
6867 ** those overwrite any prior [sqlite3_wal_hook()] settings.
6868 */
6869 SQLITE_API void *sqlite3_wal_hook(
6870 sqlite3*,
6871 int(*)(void *,sqlite3*,const char*,int),
6872 void*
6873 );
6874
6875 /*
6876 ** CAPI3REF: Configure an auto-checkpoint
6877 **
6878 ** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
6879 ** [sqlite3_wal_hook()] that causes any database on [database connection] D
6880 ** to automatically [checkpoint]
6881 ** after committing a transaction if there are N or
6882 ** more frames in the [write-ahead log] file. ^Passing zero or
6883 ** a negative value as the nFrame parameter disables automatic
6884 ** checkpoints entirely.
6885 **
6886 ** ^The callback registered by this function replaces any existing callback
6887 ** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback
6888 ** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
6889 ** configured by this function.
6890 **
6891 ** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
6892 ** from SQL.
6893 **
6894 ** ^Every new [database connection] defaults to having the auto-checkpoint
6895 ** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
6896 ** pages. The use of this interface
6897 ** is only necessary if the default setting is found to be suboptimal
6898 ** for a particular application.
6899 */
6900 SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
6901
6902 /*
6903 ** CAPI3REF: Checkpoint a database
6904 **
6905 ** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X
6906 ** on [database connection] D to be [checkpointed]. ^If X is NULL or an
6907 ** empty string, then a checkpoint is run on all databases of
6908 ** connection D. ^If the database connection D is not in
6909 ** [WAL | write-ahead log mode] then this interface is a harmless no-op.
6910 **
6911 ** ^The [wal_checkpoint pragma] can be used to invoke this interface
6912 ** from SQL. ^The [sqlite3_wal_autocheckpoint()] interface and the
6913 ** [wal_autocheckpoint pragma] can be used to cause this interface to be
6914 ** run whenever the WAL reaches a certain size threshold.
6915 **
6916 ** See also: [sqlite3_wal_checkpoint_v2()]
6917 */
6918 SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
6919
6920 /*
6921 ** CAPI3REF: Checkpoint a database
6922 **
6923 ** Run a checkpoint operation on WAL database zDb attached to database
6924 ** handle db. The specific operation is determined by the value of the
6925 ** eMode parameter:
6926 **
6927 ** <dl>
6928 ** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
6929 ** Checkpoint as many frames as possible without waiting for any database
6930 ** readers or writers to finish. Sync the db file if all frames in the log
6931 ** are checkpointed. This mode is the same as calling
6932 ** sqlite3_wal_checkpoint(). The busy-handler callback is never invoked.
6933 **
6934 ** <dt>SQLITE_CHECKPOINT_FULL<dd>
6935 ** This mode blocks (calls the busy-handler callback) until there is no
6936 ** database writer and all readers are reading from the most recent database
6937 ** snapshot. It then checkpoints all frames in the log file and syncs the
6938 ** database file. This call blocks database writers while it is running,
6939 ** but not database readers.
6940 **
6941 ** <dt>SQLITE_CHECKPOINT_RESTART<dd>
6942 ** This mode works the same way as SQLITE_CHECKPOINT_FULL, except after
6943 ** checkpointing the log file it blocks (calls the busy-handler callback)
6944 ** until all readers are reading from the database file only. This ensures
6945 ** that the next client to write to the database file restarts the log file
6946 ** from the beginning. This call blocks database writers while it is running,
6947 ** but not database readers.
6948 ** </dl>
6949 **
6950 ** If pnLog is not NULL, then *pnLog is set to the total number of frames in
6951 ** the log file before returning. If pnCkpt is not NULL, then *pnCkpt is set to
6952 ** the total number of checkpointed frames (including any that were already
6953 ** checkpointed when this function is called). *pnLog and *pnCkpt may be
6954 ** populated even if sqlite3_wal_checkpoint_v2() returns other than SQLITE_OK.
6955 ** If no values are available because of an error, they are both set to -1
6956 ** before returning to communicate this to the caller.
6957 **
6958 ** All calls obtain an exclusive "checkpoint" lock on the database file. If
6959 ** any other process is running a checkpoint operation at the same time, the
6960 ** lock cannot be obtained and SQLITE_BUSY is returned. Even if there is a
6961 ** busy-handler configured, it will not be invoked in this case.
6962 **
6963 ** The SQLITE_CHECKPOINT_FULL and RESTART modes also obtain the exclusive
6964 ** "writer" lock on the database file. If the writer lock cannot be obtained
6965 ** immediately, and a busy-handler is configured, it is invoked and the writer
6966 ** lock retried until either the busy-handler returns 0 or the lock is
6967 ** successfully obtained. The busy-handler is also invoked while waiting for
6968 ** database readers as described above. If the busy-handler returns 0 before
6969 ** the writer lock is obtained or while waiting for database readers, the
6970 ** checkpoint operation proceeds from that point in the same way as
6971 ** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible
6972 ** without blocking any further. SQLITE_BUSY is returned in this case.
6973 **
6974 ** If parameter zDb is NULL or points to a zero length string, then the
6975 ** specified operation is attempted on all WAL databases. In this case the
6976 ** values written to output parameters *pnLog and *pnCkpt are undefined. If
6977 ** an SQLITE_BUSY error is encountered when processing one or more of the
6978 ** attached WAL databases, the operation is still attempted on any remaining
6979 ** attached databases and SQLITE_BUSY is returned to the caller. If any other
6980 ** error occurs while processing an attached database, processing is abandoned
6981 ** and the error code returned to the caller immediately. If no error
6982 ** (SQLITE_BUSY or otherwise) is encountered while processing the attached
6983 ** databases, SQLITE_OK is returned.
6984 **
6985 ** If database zDb is the name of an attached database that is not in WAL
6986 ** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. If
6987 ** zDb is not NULL (or a zero length string) and is not the name of any
6988 ** attached database, SQLITE_ERROR is returned to the caller.
6989 */
6990 SQLITE_API int sqlite3_wal_checkpoint_v2(
6991 sqlite3 *db, /* Database handle */
6992 const char *zDb, /* Name of attached database (or NULL) */
6993 int eMode, /* SQLITE_CHECKPOINT_* value */
6994 int *pnLog, /* OUT: Size of WAL log in frames */
6995 int *pnCkpt /* OUT: Total number of frames checkpointed */
6996 );
6997
6998 /*
6999 ** CAPI3REF: Checkpoint operation parameters
7000 **
7001 ** These constants can be used as the 3rd parameter to
7002 ** [sqlite3_wal_checkpoint_v2()]. See the [sqlite3_wal_checkpoint_v2()]
7003 ** documentation for additional information about the meaning and use of
7004 ** each of these values.
7005 */
7006 #define SQLITE_CHECKPOINT_PASSIVE 0
7007 #define SQLITE_CHECKPOINT_FULL 1
7008 #define SQLITE_CHECKPOINT_RESTART 2
7009
7010 /*
7011 ** CAPI3REF: Virtual Table Interface Configuration
7012 **
7013 ** This function may be called by either the [xConnect] or [xCreate] method
7014 ** of a [virtual table] implementation to configure
7015 ** various facets of the virtual table interface.
7016 **
7017 ** If this interface is invoked outside the context of an xConnect or
7018 ** xCreate virtual table method then the behavior is undefined.
7019 **
7020 ** At present, there is only one option that may be configured using
7021 ** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options
7022 ** may be added in the future.
7023 */
7024 SQLITE_API int sqlite3_vtab_config(sqlite3*, int op, ...);
7025
7026 /*
7027 ** CAPI3REF: Virtual Table Configuration Options
7028 **
7029 ** These macros define the various options to the
7030 ** [sqlite3_vtab_config()] interface that [virtual table] implementations
7031 ** can use to customize and optimize their behavior.
7032 **
7033 ** <dl>
7034 ** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT
7035 ** <dd>Calls of the form
7036 ** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
7037 ** where X is an integer. If X is zero, then the [virtual table] whose
7038 ** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not
7039 ** support constraints. In this configuration (which is the default) if
7040 ** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire
7041 ** statement is rolled back as if [ON CONFLICT | OR ABORT] had been
7042 ** specified as part of the users SQL statement, regardless of the actual
7043 ** ON CONFLICT mode specified.
7044 **
7045 ** If X is non-zero, then the virtual table implementation guarantees
7046 ** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before
7047 ** any modifications to internal or persistent data structures have been made.
7048 ** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite
7049 ** is able to roll back a statement or database transaction, and abandon
7050 ** or continue processing the current SQL statement as appropriate.
7051 ** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns
7052 ** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode
7053 ** had been ABORT.
7054 **
7055 ** Virtual table implementations that are required to handle OR REPLACE
7056 ** must do so within the [xUpdate] method. If a call to the
7057 ** [sqlite3_vtab_on_conflict()] function indicates that the current ON
7058 ** CONFLICT policy is REPLACE, the virtual table implementation should
7059 ** silently replace the appropriate rows within the xUpdate callback and
7060 ** return SQLITE_OK. Or, if this is not possible, it may return
7061 ** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT
7062 ** constraint handling.
7063 ** </dl>
7064 */
7065 #define SQLITE_VTAB_CONSTRAINT_SUPPORT 1
7066
7067 /*
7068 ** CAPI3REF: Determine The Virtual Table Conflict Policy
7069 **
7070 ** This function may only be called from within a call to the [xUpdate] method
7071 ** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The
7072 ** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
7073 ** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
7074 ** of the SQL statement that triggered the call to the [xUpdate] method of the
7075 ** [virtual table].
7076 */
7077 SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *);
7078
7079 /*
7080 ** CAPI3REF: Conflict resolution modes
7081 **
7082 ** These constants are returned by [sqlite3_vtab_on_conflict()] to
7083 ** inform a [virtual table] implementation what the [ON CONFLICT] mode
7084 ** is for the SQL statement being evaluated.
7085 **
7086 ** Note that the [SQLITE_IGNORE] constant is also used as a potential
7087 ** return value from the [sqlite3_set_authorizer()] callback and that
7088 ** [SQLITE_ABORT] is also a [result code].
7089 */
7090 #define SQLITE_ROLLBACK 1
7091 /* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
7092 #define SQLITE_FAIL 3
7093 /* #define SQLITE_ABORT 4 // Also an error code */
7094 #define SQLITE_REPLACE 5
7095
7096
7097
7098 /*
7099 ** Undo the hack that converts floating point types to integer for
7100 ** builds on processors without floating point support.
7101 */
7102 #ifdef SQLITE_OMIT_FLOATING_POINT
7103 # undef double
7104 #endif
7105
7106 #ifdef __cplusplus
7107 } /* End of the 'extern "C"' block */
7108 #endif
7109 #endif
7110
7111 /*
7112 ** 2010 August 30
7113 **
7114 ** The author disclaims copyright to this source code. In place of
7115 ** a legal notice, here is a blessing:
7116 **
7117 ** May you do good and not evil.
7118 ** May you find forgiveness for yourself and forgive others.
7119 ** May you share freely, never taking more than you give.
7120 **
7121 *************************************************************************
7122 */
7123
7124 #ifndef _SQLITE3RTREE_H_
7125 #define _SQLITE3RTREE_H_
7126
7127
7128 #ifdef __cplusplus
7129 extern "C" {
7130 #endif
7131
7132 typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry;
7133
7134 /*
7135 ** Register a geometry callback named zGeom that can be used as part of an
7136 ** R-Tree geometry query as follows:
7137 **
7138 ** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...)
7139 */
7140 SQLITE_API int sqlite3_rtree_geometry_callback(
7141 sqlite3 *db,
7142 const char *zGeom,
7143 #ifdef SQLITE_RTREE_INT_ONLY
7144 int (*xGeom)(sqlite3_rtree_geometry*, int n, sqlite3_int64 *a, int *pRes),
7145 #else
7146 int (*xGeom)(sqlite3_rtree_geometry*, int n, double *a, int *pRes),
7147 #endif
7148 void *pContext
7149 );
7150
7151
7152 /*
7153 ** A pointer to a structure of the following type is passed as the first
7154 ** argument to callbacks registered using rtree_geometry_callback().
7155 */
7156 struct sqlite3_rtree_geometry {
7157 void *pContext; /* Copy of pContext passed to s_r_g_c() */
7158 int nParam; /* Size of array aParam[] */
7159 double *aParam; /* Parameters passed to SQL geom function */
7160 void *pUser; /* Callback implementation user data */
7161 void (*xDelUser)(void *); /* Called by SQLite to clean up pUser */
7162 };
7163
7164
7165 #ifdef __cplusplus
7166 } /* end of the 'extern "C"' block */
7167 #endif
7168
7169 #endif /* ifndef _SQLITE3RTREE_H_ */
7170