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security/nss/lib/sqlite/sqlite3.h

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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 "3.7.15"
111 #define SQLITE_VERSION_NUMBER 3007015
112 #define SQLITE_SOURCE_ID "2012-12-12 13:36:53 cd0b37c52658bfdf992b1e3dc467bae1835a94ae"
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() 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_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8))
487
488 /*
489 ** CAPI3REF: Flags For File Open Operations
490 **
491 ** These bit values are intended for use in the
492 ** 3rd parameter to the [sqlite3_open_v2()] interface and
493 ** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
494 */
495 #define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */
496 #define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */
497 #define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */
498 #define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */
499 #define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */
500 #define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */
501 #define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */
502 #define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */
503 #define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */
504 #define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */
505 #define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */
506 #define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */
507 #define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */
508 #define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */
509 #define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */
510 #define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */
511 #define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */
512 #define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */
513 #define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */
514 #define SQLITE_OPEN_WAL 0x00080000 /* VFS only */
515
516 /* Reserved: 0x00F00000 */
517
518 /*
519 ** CAPI3REF: Device Characteristics
520 **
521 ** The xDeviceCharacteristics method of the [sqlite3_io_methods]
522 ** object returns an integer which is a vector of these
523 ** bit values expressing I/O characteristics of the mass storage
524 ** device that holds the file that the [sqlite3_io_methods]
525 ** refers to.
526 **
527 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
528 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
529 ** mean that writes of blocks that are nnn bytes in size and
530 ** are aligned to an address which is an integer multiple of
531 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
532 ** that when data is appended to a file, the data is appended
533 ** first then the size of the file is extended, never the other
534 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
535 ** information is written to disk in the same order as calls
536 ** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
537 ** after reboot following a crash or power loss, the only bytes in a
538 ** file that were written at the application level might have changed
539 ** and that adjacent bytes, even bytes within the same sector are
540 ** guaranteed to be unchanged.
541 */
542 #define SQLITE_IOCAP_ATOMIC 0x00000001
543 #define SQLITE_IOCAP_ATOMIC512 0x00000002
544 #define SQLITE_IOCAP_ATOMIC1K 0x00000004
545 #define SQLITE_IOCAP_ATOMIC2K 0x00000008
546 #define SQLITE_IOCAP_ATOMIC4K 0x00000010
547 #define SQLITE_IOCAP_ATOMIC8K 0x00000020
548 #define SQLITE_IOCAP_ATOMIC16K 0x00000040
549 #define SQLITE_IOCAP_ATOMIC32K 0x00000080
550 #define SQLITE_IOCAP_ATOMIC64K 0x00000100
551 #define SQLITE_IOCAP_SAFE_APPEND 0x00000200
552 #define SQLITE_IOCAP_SEQUENTIAL 0x00000400
553 #define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800
554 #define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000
555
556 /*
557 ** CAPI3REF: File Locking Levels
558 **
559 ** SQLite uses one of these integer values as the second
560 ** argument to calls it makes to the xLock() and xUnlock() methods
561 ** of an [sqlite3_io_methods] object.
562 */
563 #define SQLITE_LOCK_NONE 0
564 #define SQLITE_LOCK_SHARED 1
565 #define SQLITE_LOCK_RESERVED 2
566 #define SQLITE_LOCK_PENDING 3
567 #define SQLITE_LOCK_EXCLUSIVE 4
568
569 /*
570 ** CAPI3REF: Synchronization Type Flags
571 **
572 ** When SQLite invokes the xSync() method of an
573 ** [sqlite3_io_methods] object it uses a combination of
574 ** these integer values as the second argument.
575 **
576 ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
577 ** sync operation only needs to flush data to mass storage. Inode
578 ** information need not be flushed. If the lower four bits of the flag
579 ** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
580 ** If the lower four bits equal SQLITE_SYNC_FULL, that means
581 ** to use Mac OS X style fullsync instead of fsync().
582 **
583 ** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
584 ** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
585 ** settings. The [synchronous pragma] determines when calls to the
586 ** xSync VFS method occur and applies uniformly across all platforms.
587 ** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
588 ** energetic or rigorous or forceful the sync operations are and
589 ** only make a difference on Mac OSX for the default SQLite code.
590 ** (Third-party VFS implementations might also make the distinction
591 ** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
592 ** operating systems natively supported by SQLite, only Mac OSX
593 ** cares about the difference.)
594 */
595 #define SQLITE_SYNC_NORMAL 0x00002
596 #define SQLITE_SYNC_FULL 0x00003
597 #define SQLITE_SYNC_DATAONLY 0x00010
598
599 /*
600 ** CAPI3REF: OS Interface Open File Handle
601 **
602 ** An [sqlite3_file] object represents an open file in the
603 ** [sqlite3_vfs | OS interface layer]. Individual OS interface
604 ** implementations will
605 ** want to subclass this object by appending additional fields
606 ** for their own use. The pMethods entry is a pointer to an
607 ** [sqlite3_io_methods] object that defines methods for performing
608 ** I/O operations on the open file.
609 */
610 typedef struct sqlite3_file sqlite3_file;
611 struct sqlite3_file {
612 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */
613 };
614
615 /*
616 ** CAPI3REF: OS Interface File Virtual Methods Object
617 **
618 ** Every file opened by the [sqlite3_vfs.xOpen] method populates an
619 ** [sqlite3_file] object (or, more commonly, a subclass of the
620 ** [sqlite3_file] object) with a pointer to an instance of this object.
621 ** This object defines the methods used to perform various operations
622 ** against the open file represented by the [sqlite3_file] object.
623 **
624 ** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element
625 ** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
626 ** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The
627 ** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
628 ** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
629 ** to NULL.
630 **
631 ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
632 ** [SQLITE_SYNC_FULL]. The first choice is the normal fsync().
633 ** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY]
634 ** flag may be ORed in to indicate that only the data of the file
635 ** and not its inode needs to be synced.
636 **
637 ** The integer values to xLock() and xUnlock() are one of
638 ** <ul>
639 ** <li> [SQLITE_LOCK_NONE],
640 ** <li> [SQLITE_LOCK_SHARED],
641 ** <li> [SQLITE_LOCK_RESERVED],
642 ** <li> [SQLITE_LOCK_PENDING], or
643 ** <li> [SQLITE_LOCK_EXCLUSIVE].
644 ** </ul>
645 ** xLock() increases the lock. xUnlock() decreases the lock.
646 ** The xCheckReservedLock() method checks whether any database connection,
647 ** either in this process or in some other process, is holding a RESERVED,
648 ** PENDING, or EXCLUSIVE lock on the file. It returns true
649 ** if such a lock exists and false otherwise.
650 **
651 ** The xFileControl() method is a generic interface that allows custom
652 ** VFS implementations to directly control an open file using the
653 ** [sqlite3_file_control()] interface. The second "op" argument is an
654 ** integer opcode. The third argument is a generic pointer intended to
655 ** point to a structure that may contain arguments or space in which to
656 ** write return values. Potential uses for xFileControl() might be
657 ** functions to enable blocking locks with timeouts, to change the
658 ** locking strategy (for example to use dot-file locks), to inquire
659 ** about the status of a lock, or to break stale locks. The SQLite
660 ** core reserves all opcodes less than 100 for its own use.
661 ** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available.
662 ** Applications that define a custom xFileControl method should use opcodes
663 ** greater than 100 to avoid conflicts. VFS implementations should
664 ** return [SQLITE_NOTFOUND] for file control opcodes that they do not
665 ** recognize.
666 **
667 ** The xSectorSize() method returns the sector size of the
668 ** device that underlies the file. The sector size is the
669 ** minimum write that can be performed without disturbing
670 ** other bytes in the file. The xDeviceCharacteristics()
671 ** method returns a bit vector describing behaviors of the
672 ** underlying device:
673 **
674 ** <ul>
675 ** <li> [SQLITE_IOCAP_ATOMIC]
676 ** <li> [SQLITE_IOCAP_ATOMIC512]
677 ** <li> [SQLITE_IOCAP_ATOMIC1K]
678 ** <li> [SQLITE_IOCAP_ATOMIC2K]
679 ** <li> [SQLITE_IOCAP_ATOMIC4K]
680 ** <li> [SQLITE_IOCAP_ATOMIC8K]
681 ** <li> [SQLITE_IOCAP_ATOMIC16K]
682 ** <li> [SQLITE_IOCAP_ATOMIC32K]
683 ** <li> [SQLITE_IOCAP_ATOMIC64K]
684 ** <li> [SQLITE_IOCAP_SAFE_APPEND]
685 ** <li> [SQLITE_IOCAP_SEQUENTIAL]
686 ** </ul>
687 **
688 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
689 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
690 ** mean that writes of blocks that are nnn bytes in size and
691 ** are aligned to an address which is an integer multiple of
692 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
693 ** that when data is appended to a file, the data is appended
694 ** first then the size of the file is extended, never the other
695 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
696 ** information is written to disk in the same order as calls
697 ** to xWrite().
698 **
699 ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
700 ** in the unread portions of the buffer with zeros. A VFS that
701 ** fails to zero-fill short reads might seem to work. However,
702 ** failure to zero-fill short reads will eventually lead to
703 ** database corruption.
704 */
705 typedef struct sqlite3_io_methods sqlite3_io_methods;
706 struct sqlite3_io_methods {
707 int iVersion;
708 int (*xClose)(sqlite3_file*);
709 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
710 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
711 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
712 int (*xSync)(sqlite3_file*, int flags);
713 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
714 int (*xLock)(sqlite3_file*, int);
715 int (*xUnlock)(sqlite3_file*, int);
716 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
717 int (*xFileControl)(sqlite3_file*, int op, void *pArg);
718 int (*xSectorSize)(sqlite3_file*);
719 int (*xDeviceCharacteristics)(sqlite3_file*);
720 /* Methods above are valid for version 1 */
721 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
722 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
723 void (*xShmBarrier)(sqlite3_file*);
724 int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
725 /* Methods above are valid for version 2 */
726 /* Additional methods may be added in future releases */
727 };
728
729 /*
730 ** CAPI3REF: Standard File Control Opcodes
731 **
732 ** These integer constants are opcodes for the xFileControl method
733 ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
734 ** interface.
735 **
736 ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This
737 ** opcode causes the xFileControl method to write the current state of
738 ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
739 ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
740 ** into an integer that the pArg argument points to. This capability
741 ** is used during testing and only needs to be supported when SQLITE_TEST
742 ** is defined.
743 ** <ul>
744 ** <li>[[SQLITE_FCNTL_SIZE_HINT]]
745 ** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
746 ** layer a hint of how large the database file will grow to be during the
747 ** current transaction. This hint is not guaranteed to be accurate but it
748 ** is often close. The underlying VFS might choose to preallocate database
749 ** file space based on this hint in order to help writes to the database
750 ** file run faster.
751 **
752 ** <li>[[SQLITE_FCNTL_CHUNK_SIZE]]
753 ** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
754 ** extends and truncates the database file in chunks of a size specified
755 ** by the user. The fourth argument to [sqlite3_file_control()] should
756 ** point to an integer (type int) containing the new chunk-size to use
757 ** for the nominated database. Allocating database file space in large
758 ** chunks (say 1MB at a time), may reduce file-system fragmentation and
759 ** improve performance on some systems.
760 **
761 ** <li>[[SQLITE_FCNTL_FILE_POINTER]]
762 ** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
763 ** to the [sqlite3_file] object associated with a particular database
764 ** connection. See the [sqlite3_file_control()] documentation for
765 ** additional information.
766 **
767 ** <li>[[SQLITE_FCNTL_SYNC_OMITTED]]
768 ** ^(The [SQLITE_FCNTL_SYNC_OMITTED] opcode is generated internally by
769 ** SQLite and sent to all VFSes in place of a call to the xSync method
770 ** when the database connection has [PRAGMA synchronous] set to OFF.)^
771 ** Some specialized VFSes need this signal in order to operate correctly
772 ** when [PRAGMA synchronous | PRAGMA synchronous=OFF] is set, but most
773 ** VFSes do not need this signal and should silently ignore this opcode.
774 ** Applications should not call [sqlite3_file_control()] with this
775 ** opcode as doing so may disrupt the operation of the specialized VFSes
776 ** that do require it.
777 **
778 ** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]]
779 ** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
780 ** retry counts and intervals for certain disk I/O operations for the
781 ** windows [VFS] in order to provide robustness in the presence of
782 ** anti-virus programs. By default, the windows VFS will retry file read,
783 ** file write, and file delete operations up to 10 times, with a delay
784 ** of 25 milliseconds before the first retry and with the delay increasing
785 ** by an additional 25 milliseconds with each subsequent retry. This
786 ** opcode allows these two values (10 retries and 25 milliseconds of delay)
787 ** to be adjusted. The values are changed for all database connections
788 ** within the same process. The argument is a pointer to an array of two
789 ** integers where the first integer i the new retry count and the second
790 ** integer is the delay. If either integer is negative, then the setting
791 ** is not changed but instead the prior value of that setting is written
792 ** into the array entry, allowing the current retry settings to be
793 ** interrogated. The zDbName parameter is ignored.
794 **
795 ** <li>[[SQLITE_FCNTL_PERSIST_WAL]]
796 ** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
797 ** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary
798 ** write ahead log and shared memory files used for transaction control
799 ** are automatically deleted when the latest connection to the database
800 ** closes. Setting persistent WAL mode causes those files to persist after
801 ** close. Persisting the files is useful when other processes that do not
802 ** have write permission on the directory containing the database file want
803 ** to read the database file, as the WAL and shared memory files must exist
804 ** in order for the database to be readable. The fourth parameter to
805 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
806 ** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
807 ** WAL mode. If the integer is -1, then it is overwritten with the current
808 ** WAL persistence setting.
809 **
810 ** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]]
811 ** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
812 ** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting
813 ** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
814 ** xDeviceCharacteristics methods. 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 zero-damage mode or 1 to enable zero-damage
817 ** mode. If the integer is -1, then it is overwritten with the current
818 ** zero-damage mode setting.
819 **
820 ** <li>[[SQLITE_FCNTL_OVERWRITE]]
821 ** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
822 ** a write transaction to indicate that, unless it is rolled back for some
823 ** reason, the entire database file will be overwritten by the current
824 ** transaction. This is used by VACUUM operations.
825 **
826 ** <li>[[SQLITE_FCNTL_VFSNAME]]
827 ** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
828 ** all [VFSes] in the VFS stack. The names are of all VFS shims and the
829 ** final bottom-level VFS are written into memory obtained from
830 ** [sqlite3_malloc()] and the result is stored in the char* variable
831 ** that the fourth parameter of [sqlite3_file_control()] points to.
832 ** The caller is responsible for freeing the memory when done. As with
833 ** all file-control actions, there is no guarantee that this will actually
834 ** do anything. Callers should initialize the char* variable to a NULL
835 ** pointer in case this file-control is not implemented. This file-control
836 ** is intended for diagnostic use only.
837 **
838 ** <li>[[SQLITE_FCNTL_PRAGMA]]
839 ** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA]
840 ** file control is sent to the open [sqlite3_file] object corresponding
841 ** to the database file to which the pragma statement refers. ^The argument
842 ** to the [SQLITE_FCNTL_PRAGMA] file control is an array of
843 ** pointers to strings (char**) in which the second element of the array
844 ** is the name of the pragma and the third element is the argument to the
845 ** pragma or NULL if the pragma has no argument. ^The handler for an
846 ** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element
847 ** of the char** argument point to a string obtained from [sqlite3_mprintf()]
848 ** or the equivalent and that string will become the result of the pragma or
849 ** the error message if the pragma fails. ^If the
850 ** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal
851 ** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA]
852 ** file control returns [SQLITE_OK], then the parser assumes that the
853 ** VFS has handled the PRAGMA itself and the parser generates a no-op
854 ** prepared statement. ^If the [SQLITE_FCNTL_PRAGMA] file control returns
855 ** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means
856 ** that the VFS encountered an error while handling the [PRAGMA] and the
857 ** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA]
858 ** file control occurs at the beginning of pragma statement analysis and so
859 ** it is able to override built-in [PRAGMA] statements.
860 **
861 ** <li>[[SQLITE_FCNTL_BUSYHANDLER]]
862 ** ^This file-control may be invoked by SQLite on the database file handle
863 ** shortly after it is opened in order to provide a custom VFS with access
864 ** to the connections busy-handler callback. The argument is of type (void **)
865 ** - an array of two (void *) values. The first (void *) actually points
866 ** to a function of type (int (*)(void *)). In order to invoke the connections
867 ** busy-handler, this function should be invoked with the second (void *) in
868 ** the array as the only argument. If it returns non-zero, then the operation
869 ** should be retried. If it returns zero, the custom VFS should abandon the
870 ** current operation.
871 **
872 ** <li>[[SQLITE_FCNTL_TEMPFILENAME]]
873 ** ^Application can invoke this file-control to have SQLite generate a
874 ** temporary filename using the same algorithm that is followed to generate
875 ** temporary filenames for TEMP tables and other internal uses. The
876 ** argument should be a char** which will be filled with the filename
877 ** written into memory obtained from [sqlite3_malloc()]. The caller should
878 ** invoke [sqlite3_free()] on the result to avoid a memory leak.
879 **
880 ** </ul>
881 */
882 #define SQLITE_FCNTL_LOCKSTATE 1
883 #define SQLITE_GET_LOCKPROXYFILE 2
884 #define SQLITE_SET_LOCKPROXYFILE 3
885 #define SQLITE_LAST_ERRNO 4
886 #define SQLITE_FCNTL_SIZE_HINT 5
887 #define SQLITE_FCNTL_CHUNK_SIZE 6
888 #define SQLITE_FCNTL_FILE_POINTER 7
889 #define SQLITE_FCNTL_SYNC_OMITTED 8
890 #define SQLITE_FCNTL_WIN32_AV_RETRY 9
891 #define SQLITE_FCNTL_PERSIST_WAL 10
892 #define SQLITE_FCNTL_OVERWRITE 11
893 #define SQLITE_FCNTL_VFSNAME 12
894 #define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13
895 #define SQLITE_FCNTL_PRAGMA 14
896 #define SQLITE_FCNTL_BUSYHANDLER 15
897 #define SQLITE_FCNTL_TEMPFILENAME 16
898
899 /*
900 ** CAPI3REF: Mutex Handle
901 **
902 ** The mutex module within SQLite defines [sqlite3_mutex] to be an
903 ** abstract type for a mutex object. The SQLite core never looks
904 ** at the internal representation of an [sqlite3_mutex]. It only
905 ** deals with pointers to the [sqlite3_mutex] object.
906 **
907 ** Mutexes are created using [sqlite3_mutex_alloc()].
908 */
909 typedef struct sqlite3_mutex sqlite3_mutex;
910
911 /*
912 ** CAPI3REF: OS Interface Object
913 **
914 ** An instance of the sqlite3_vfs object defines the interface between
915 ** the SQLite core and the underlying operating system. The "vfs"
916 ** in the name of the object stands for "virtual file system". See
917 ** the [VFS | VFS documentation] for further information.
918 **
919 ** The value of the iVersion field is initially 1 but may be larger in
920 ** future versions of SQLite. Additional fields may be appended to this
921 ** object when the iVersion value is increased. Note that the structure
922 ** of the sqlite3_vfs object changes in the transaction between
923 ** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not
924 ** modified.
925 **
926 ** The szOsFile field is the size of the subclassed [sqlite3_file]
927 ** structure used by this VFS. mxPathname is the maximum length of
928 ** a pathname in this VFS.
929 **
930 ** Registered sqlite3_vfs objects are kept on a linked list formed by
931 ** the pNext pointer. The [sqlite3_vfs_register()]
932 ** and [sqlite3_vfs_unregister()] interfaces manage this list
933 ** in a thread-safe way. The [sqlite3_vfs_find()] interface
934 ** searches the list. Neither the application code nor the VFS
935 ** implementation should use the pNext pointer.
936 **
937 ** The pNext field is the only field in the sqlite3_vfs
938 ** structure that SQLite will ever modify. SQLite will only access
939 ** or modify this field while holding a particular static mutex.
940 ** The application should never modify anything within the sqlite3_vfs
941 ** object once the object has been registered.
942 **
943 ** The zName field holds the name of the VFS module. The name must
944 ** be unique across all VFS modules.
945 **
946 ** [[sqlite3_vfs.xOpen]]
947 ** ^SQLite guarantees that the zFilename parameter to xOpen
948 ** is either a NULL pointer or string obtained
949 ** from xFullPathname() with an optional suffix added.
950 ** ^If a suffix is added to the zFilename parameter, it will
951 ** consist of a single "-" character followed by no more than
952 ** 11 alphanumeric and/or "-" characters.
953 ** ^SQLite further guarantees that
954 ** the string will be valid and unchanged until xClose() is
955 ** called. Because of the previous sentence,
956 ** the [sqlite3_file] can safely store a pointer to the
957 ** filename if it needs to remember the filename for some reason.
958 ** If the zFilename parameter to xOpen is a NULL pointer then xOpen
959 ** must invent its own temporary name for the file. ^Whenever the
960 ** xFilename parameter is NULL it will also be the case that the
961 ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
962 **
963 ** The flags argument to xOpen() includes all bits set in
964 ** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()]
965 ** or [sqlite3_open16()] is used, then flags includes at least
966 ** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE].
967 ** If xOpen() opens a file read-only then it sets *pOutFlags to
968 ** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set.
969 **
970 ** ^(SQLite will also add one of the following flags to the xOpen()
971 ** call, depending on the object being opened:
972 **
973 ** <ul>
974 ** <li> [SQLITE_OPEN_MAIN_DB]
975 ** <li> [SQLITE_OPEN_MAIN_JOURNAL]
976 ** <li> [SQLITE_OPEN_TEMP_DB]
977 ** <li> [SQLITE_OPEN_TEMP_JOURNAL]
978 ** <li> [SQLITE_OPEN_TRANSIENT_DB]
979 ** <li> [SQLITE_OPEN_SUBJOURNAL]
980 ** <li> [SQLITE_OPEN_MASTER_JOURNAL]
981 ** <li> [SQLITE_OPEN_WAL]
982 ** </ul>)^
983 **
984 ** The file I/O implementation can use the object type flags to
985 ** change the way it deals with files. For example, an application
986 ** that does not care about crash recovery or rollback might make
987 ** the open of a journal file a no-op. Writes to this journal would
988 ** also be no-ops, and any attempt to read the journal would return
989 ** SQLITE_IOERR. Or the implementation might recognize that a database
990 ** file will be doing page-aligned sector reads and writes in a random
991 ** order and set up its I/O subsystem accordingly.
992 **
993 ** SQLite might also add one of the following flags to the xOpen method:
994 **
995 ** <ul>
996 ** <li> [SQLITE_OPEN_DELETEONCLOSE]
997 ** <li> [SQLITE_OPEN_EXCLUSIVE]
998 ** </ul>
999 **
1000 ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
1001 ** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE]
1002 ** will be set for TEMP databases and their journals, transient
1003 ** databases, and subjournals.
1004 **
1005 ** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
1006 ** with the [SQLITE_OPEN_CREATE] flag, which are both directly
1007 ** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
1008 ** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
1009 ** SQLITE_OPEN_CREATE, is used to indicate that file should always
1010 ** be created, and that it is an error if it already exists.
1011 ** It is <i>not</i> used to indicate the file should be opened
1012 ** for exclusive access.
1013 **
1014 ** ^At least szOsFile bytes of memory are allocated by SQLite
1015 ** to hold the [sqlite3_file] structure passed as the third
1016 ** argument to xOpen. The xOpen method does not have to
1017 ** allocate the structure; it should just fill it in. Note that
1018 ** the xOpen method must set the sqlite3_file.pMethods to either
1019 ** a valid [sqlite3_io_methods] object or to NULL. xOpen must do
1020 ** this even if the open fails. SQLite expects that the sqlite3_file.pMethods
1021 ** element will be valid after xOpen returns regardless of the success
1022 ** or failure of the xOpen call.
1023 **
1024 ** [[sqlite3_vfs.xAccess]]
1025 ** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
1026 ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
1027 ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
1028 ** to test whether a file is at least readable. The file can be a
1029 ** directory.
1030 **
1031 ** ^SQLite will always allocate at least mxPathname+1 bytes for the
1032 ** output buffer xFullPathname. The exact size of the output buffer
1033 ** is also passed as a parameter to both methods. If the output buffer
1034 ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
1035 ** handled as a fatal error by SQLite, vfs implementations should endeavor
1036 ** to prevent this by setting mxPathname to a sufficiently large value.
1037 **
1038 ** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
1039 ** interfaces are not strictly a part of the filesystem, but they are
1040 ** included in the VFS structure for completeness.
1041 ** The xRandomness() function attempts to return nBytes bytes
1042 ** of good-quality randomness into zOut. The return value is
1043 ** the actual number of bytes of randomness obtained.
1044 ** The xSleep() method causes the calling thread to sleep for at
1045 ** least the number of microseconds given. ^The xCurrentTime()
1046 ** method returns a Julian Day Number for the current date and time as
1047 ** a floating point value.
1048 ** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
1049 ** Day Number multiplied by 86400000 (the number of milliseconds in
1050 ** a 24-hour day).
1051 ** ^SQLite will use the xCurrentTimeInt64() method to get the current
1052 ** date and time if that method is available (if iVersion is 2 or
1053 ** greater and the function pointer is not NULL) and will fall back
1054 ** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
1055 **
1056 ** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
1057 ** are not used by the SQLite core. These optional interfaces are provided
1058 ** by some VFSes to facilitate testing of the VFS code. By overriding
1059 ** system calls with functions under its control, a test program can
1060 ** simulate faults and error conditions that would otherwise be difficult
1061 ** or impossible to induce. The set of system calls that can be overridden
1062 ** varies from one VFS to another, and from one version of the same VFS to the
1063 ** next. Applications that use these interfaces must be prepared for any
1064 ** or all of these interfaces to be NULL or for their behavior to change
1065 ** from one release to the next. Applications must not attempt to access
1066 ** any of these methods if the iVersion of the VFS is less than 3.
1067 */
1068 typedef struct sqlite3_vfs sqlite3_vfs;
1069 typedef void (*sqlite3_syscall_ptr)(void);
1070 struct sqlite3_vfs {
1071 int iVersion; /* Structure version number (currently 3) */
1072 int szOsFile; /* Size of subclassed sqlite3_file */
1073 int mxPathname; /* Maximum file pathname length */
1074 sqlite3_vfs *pNext; /* Next registered VFS */
1075 const char *zName; /* Name of this virtual file system */
1076 void *pAppData; /* Pointer to application-specific data */
1077 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
1078 int flags, int *pOutFlags);
1079 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
1080 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
1081 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
1082 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
1083 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
1084 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
1085 void (*xDlClose)(sqlite3_vfs*, void*);
1086 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
1087 int (*xSleep)(sqlite3_vfs*, int microseconds);
1088 int (*xCurrentTime)(sqlite3_vfs*, double*);
1089 int (*xGetLastError)(sqlite3_vfs*, int, char *);
1090 /*
1091 ** The methods above are in version 1 of the sqlite_vfs object
1092 ** definition. Those that follow are added in version 2 or later
1093 */
1094 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
1095 /*
1096 ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
1097 ** Those below are for version 3 and greater.
1098 */
1099 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
1100 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
1101 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
1102 /*
1103 ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
1104 ** New fields may be appended in figure versions. The iVersion
1105 ** value will increment whenever this happens.
1106 */
1107 };
1108
1109 /*
1110 ** CAPI3REF: Flags for the xAccess VFS method
1111 **
1112 ** These integer constants can be used as the third parameter to
1113 ** the xAccess method of an [sqlite3_vfs] object. They determine
1114 ** what kind of permissions the xAccess method is looking for.
1115 ** With SQLITE_ACCESS_EXISTS, the xAccess method
1116 ** simply checks whether the file exists.
1117 ** With SQLITE_ACCESS_READWRITE, the xAccess method
1118 ** checks whether the named directory is both readable and writable
1119 ** (in other words, if files can be added, removed, and renamed within
1120 ** the directory).
1121 ** The SQLITE_ACCESS_READWRITE constant is currently used only by the
1122 ** [temp_store_directory pragma], though this could change in a future
1123 ** release of SQLite.
1124 ** With SQLITE_ACCESS_READ, the xAccess method
1125 ** checks whether the file is readable. The SQLITE_ACCESS_READ constant is
1126 ** currently unused, though it might be used in a future release of
1127 ** SQLite.
1128 */
1129 #define SQLITE_ACCESS_EXISTS 0
1130 #define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */
1131 #define SQLITE_ACCESS_READ 2 /* Unused */
1132
1133 /*
1134 ** CAPI3REF: Flags for the xShmLock VFS method
1135 **
1136 ** These integer constants define the various locking operations
1137 ** allowed by the xShmLock method of [sqlite3_io_methods]. The
1138 ** following are the only legal combinations of flags to the
1139 ** xShmLock method:
1140 **
1141 ** <ul>
1142 ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
1143 ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
1144 ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
1145 ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
1146 ** </ul>
1147 **
1148 ** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
1149 ** was given no the corresponding lock.
1150 **
1151 ** The xShmLock method can transition between unlocked and SHARED or
1152 ** between unlocked and EXCLUSIVE. It cannot transition between SHARED
1153 ** and EXCLUSIVE.
1154 */
1155 #define SQLITE_SHM_UNLOCK 1
1156 #define SQLITE_SHM_LOCK 2
1157 #define SQLITE_SHM_SHARED 4
1158 #define SQLITE_SHM_EXCLUSIVE 8
1159
1160 /*
1161 ** CAPI3REF: Maximum xShmLock index
1162 **
1163 ** The xShmLock method on [sqlite3_io_methods] may use values
1164 ** between 0 and this upper bound as its "offset" argument.
1165 ** The SQLite core will never attempt to acquire or release a
1166 ** lock outside of this range
1167 */
1168 #define SQLITE_SHM_NLOCK 8
1169
1170
1171 /*
1172 ** CAPI3REF: Initialize The SQLite Library
1173 **
1174 ** ^The sqlite3_initialize() routine initializes the
1175 ** SQLite library. ^The sqlite3_shutdown() routine
1176 ** deallocates any resources that were allocated by sqlite3_initialize().
1177 ** These routines are designed to aid in process initialization and
1178 ** shutdown on embedded systems. Workstation applications using
1179 ** SQLite normally do not need to invoke either of these routines.
1180 **
1181 ** A call to sqlite3_initialize() is an "effective" call if it is
1182 ** the first time sqlite3_initialize() is invoked during the lifetime of
1183 ** the process, or if it is the first time sqlite3_initialize() is invoked
1184 ** following a call to sqlite3_shutdown(). ^(Only an effective call
1185 ** of sqlite3_initialize() does any initialization. All other calls
1186 ** are harmless no-ops.)^
1187 **
1188 ** A call to sqlite3_shutdown() is an "effective" call if it is the first
1189 ** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only
1190 ** an effective call to sqlite3_shutdown() does any deinitialization.
1191 ** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
1192 **
1193 ** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
1194 ** is not. The sqlite3_shutdown() interface must only be called from a
1195 ** single thread. All open [database connections] must be closed and all
1196 ** other SQLite resources must be deallocated prior to invoking
1197 ** sqlite3_shutdown().
1198 **
1199 ** Among other things, ^sqlite3_initialize() will invoke
1200 ** sqlite3_os_init(). Similarly, ^sqlite3_shutdown()
1201 ** will invoke sqlite3_os_end().
1202 **
1203 ** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
1204 ** ^If for some reason, sqlite3_initialize() is unable to initialize
1205 ** the library (perhaps it is unable to allocate a needed resource such
1206 ** as a mutex) it returns an [error code] other than [SQLITE_OK].
1207 **
1208 ** ^The sqlite3_initialize() routine is called internally by many other
1209 ** SQLite interfaces so that an application usually does not need to
1210 ** invoke sqlite3_initialize() directly. For example, [sqlite3_open()]
1211 ** calls sqlite3_initialize() so the SQLite library will be automatically
1212 ** initialized when [sqlite3_open()] is called if it has not be initialized
1213 ** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
1214 ** compile-time option, then the automatic calls to sqlite3_initialize()
1215 ** are omitted and the application must call sqlite3_initialize() directly
1216 ** prior to using any other SQLite interface. For maximum portability,
1217 ** it is recommended that applications always invoke sqlite3_initialize()
1218 ** directly prior to using any other SQLite interface. Future releases
1219 ** of SQLite may require this. In other words, the behavior exhibited
1220 ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
1221 ** default behavior in some future release of SQLite.
1222 **
1223 ** The sqlite3_os_init() routine does operating-system specific
1224 ** initialization of the SQLite library. The sqlite3_os_end()
1225 ** routine undoes the effect of sqlite3_os_init(). Typical tasks
1226 ** performed by these routines include allocation or deallocation
1227 ** of static resources, initialization of global variables,
1228 ** setting up a default [sqlite3_vfs] module, or setting up
1229 ** a default configuration using [sqlite3_config()].
1230 **
1231 ** The application should never invoke either sqlite3_os_init()
1232 ** or sqlite3_os_end() directly. The application should only invoke
1233 ** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init()
1234 ** interface is called automatically by sqlite3_initialize() and
1235 ** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate
1236 ** implementations for sqlite3_os_init() and sqlite3_os_end()
1237 ** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
1238 ** When [custom builds | built for other platforms]
1239 ** (using the [SQLITE_OS_OTHER=1] compile-time
1240 ** option) the application must supply a suitable implementation for
1241 ** sqlite3_os_init() and sqlite3_os_end(). An application-supplied
1242 ** implementation of sqlite3_os_init() or sqlite3_os_end()
1243 ** must return [SQLITE_OK] on success and some other [error code] upon
1244 ** failure.
1245 */
1246 SQLITE_API int sqlite3_initialize(void);
1247 SQLITE_API int sqlite3_shutdown(void);
1248 SQLITE_API int sqlite3_os_init(void);
1249 SQLITE_API int sqlite3_os_end(void);
1250
1251 /*
1252 ** CAPI3REF: Configuring The SQLite Library
1253 **
1254 ** The sqlite3_config() interface is used to make global configuration
1255 ** changes to SQLite in order to tune SQLite to the specific needs of
1256 ** the application. The default configuration is recommended for most
1257 ** applications and so this routine is usually not necessary. It is
1258 ** provided to support rare applications with unusual needs.
1259 **
1260 ** The sqlite3_config() interface is not threadsafe. The application
1261 ** must insure that no other SQLite interfaces are invoked by other
1262 ** threads while sqlite3_config() is running. Furthermore, sqlite3_config()
1263 ** may only be invoked prior to library initialization using
1264 ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
1265 ** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
1266 ** [sqlite3_shutdown()] then it will return SQLITE_MISUSE.
1267 ** Note, however, that ^sqlite3_config() can be called as part of the
1268 ** implementation of an application-defined [sqlite3_os_init()].
1269 **
1270 ** The first argument to sqlite3_config() is an integer
1271 ** [configuration option] that determines
1272 ** what property of SQLite is to be configured. Subsequent arguments
1273 ** vary depending on the [configuration option]
1274 ** in the first argument.
1275 **
1276 ** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
1277 ** ^If the option is unknown or SQLite is unable to set the option
1278 ** then this routine returns a non-zero [error code].
1279 */
1280 SQLITE_API int sqlite3_config(int, ...);
1281
1282 /*
1283 ** CAPI3REF: Configure database connections
1284 **
1285 ** The sqlite3_db_config() interface is used to make configuration
1286 ** changes to a [database connection]. The interface is similar to
1287 ** [sqlite3_config()] except that the changes apply to a single
1288 ** [database connection] (specified in the first argument).
1289 **
1290 ** The second argument to sqlite3_db_config(D,V,...) is the
1291 ** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code
1292 ** that indicates what aspect of the [database connection] is being configured.
1293 ** Subsequent arguments vary depending on the configuration verb.
1294 **
1295 ** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
1296 ** the call is considered successful.
1297 */
1298 SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...);
1299
1300 /*
1301 ** CAPI3REF: Memory Allocation Routines
1302 **
1303 ** An instance of this object defines the interface between SQLite
1304 ** and low-level memory allocation routines.
1305 **
1306 ** This object is used in only one place in the SQLite interface.
1307 ** A pointer to an instance of this object is the argument to
1308 ** [sqlite3_config()] when the configuration option is
1309 ** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].
1310 ** By creating an instance of this object
1311 ** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
1312 ** during configuration, an application can specify an alternative
1313 ** memory allocation subsystem for SQLite to use for all of its
1314 ** dynamic memory needs.
1315 **
1316 ** Note that SQLite comes with several [built-in memory allocators]
1317 ** that are perfectly adequate for the overwhelming majority of applications
1318 ** and that this object is only useful to a tiny minority of applications
1319 ** with specialized memory allocation requirements. This object is
1320 ** also used during testing of SQLite in order to specify an alternative
1321 ** memory allocator that simulates memory out-of-memory conditions in
1322 ** order to verify that SQLite recovers gracefully from such
1323 ** conditions.
1324 **
1325 ** The xMalloc, xRealloc, and xFree methods must work like the
1326 ** malloc(), realloc() and free() functions from the standard C library.
1327 ** ^SQLite guarantees that the second argument to
1328 ** xRealloc is always a value returned by a prior call to xRoundup.
1329 **
1330 ** xSize should return the allocated size of a memory allocation
1331 ** previously obtained from xMalloc or xRealloc. The allocated size
1332 ** is always at least as big as the requested size but may be larger.
1333 **
1334 ** The xRoundup method returns what would be the allocated size of
1335 ** a memory allocation given a particular requested size. Most memory
1336 ** allocators round up memory allocations at least to the next multiple
1337 ** of 8. Some allocators round up to a larger multiple or to a power of 2.
1338 ** Every memory allocation request coming in through [sqlite3_malloc()]
1339 ** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0,
1340 ** that causes the corresponding memory allocation to fail.
1341 **
1342 ** The xInit method initializes the memory allocator. (For example,
1343 ** it might allocate any require mutexes or initialize internal data
1344 ** structures. The xShutdown method is invoked (indirectly) by
1345 ** [sqlite3_shutdown()] and should deallocate any resources acquired
1346 ** by xInit. The pAppData pointer is used as the only parameter to
1347 ** xInit and xShutdown.
1348 **
1349 ** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes
1350 ** the xInit method, so the xInit method need not be threadsafe. The
1351 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
1352 ** not need to be threadsafe either. For all other methods, SQLite
1353 ** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
1354 ** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
1355 ** it is by default) and so the methods are automatically serialized.
1356 ** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
1357 ** methods must be threadsafe or else make their own arrangements for
1358 ** serialization.
1359 **
1360 ** SQLite will never invoke xInit() more than once without an intervening
1361 ** call to xShutdown().
1362 */
1363 typedef struct sqlite3_mem_methods sqlite3_mem_methods;
1364 struct sqlite3_mem_methods {
1365 void *(*xMalloc)(int); /* Memory allocation function */
1366 void (*xFree)(void*); /* Free a prior allocation */
1367 void *(*xRealloc)(void*,int); /* Resize an allocation */
1368 int (*xSize)(void*); /* Return the size of an allocation */
1369 int (*xRoundup)(int); /* Round up request size to allocation size */
1370 int (*xInit)(void*); /* Initialize the memory allocator */
1371 void (*xShutdown)(void*); /* Deinitialize the memory allocator */
1372 void *pAppData; /* Argument to xInit() and xShutdown() */
1373 };
1374
1375 /*
1376 ** CAPI3REF: Configuration Options
1377 ** KEYWORDS: {configuration option}
1378 **
1379 ** These constants are the available integer configuration options that
1380 ** can be passed as the first argument to the [sqlite3_config()] interface.
1381 **
1382 ** New configuration options may be added in future releases of SQLite.
1383 ** Existing configuration options might be discontinued. Applications
1384 ** should check the return code from [sqlite3_config()] to make sure that
1385 ** the call worked. The [sqlite3_config()] interface will return a
1386 ** non-zero [error code] if a discontinued or unsupported configuration option
1387 ** is invoked.
1388 **
1389 ** <dl>
1390 ** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
1391 ** <dd>There are no arguments to this option. ^This option sets the
1392 ** [threading mode] to Single-thread. In other words, it disables
1393 ** all mutexing and puts SQLite into a mode where it can only be used
1394 ** by a single thread. ^If SQLite is compiled with
1395 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1396 ** it is not possible to change the [threading mode] from its default
1397 ** value of Single-thread and so [sqlite3_config()] will return
1398 ** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
1399 ** configuration option.</dd>
1400 **
1401 ** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt>
1402 ** <dd>There are no arguments to this option. ^This option sets the
1403 ** [threading mode] to Multi-thread. In other words, it disables
1404 ** mutexing on [database connection] and [prepared statement] objects.
1405 ** The application is responsible for serializing access to
1406 ** [database connections] and [prepared statements]. But other mutexes
1407 ** are enabled so that SQLite will be safe to use in a multi-threaded
1408 ** environment as long as no two threads attempt to use the same
1409 ** [database connection] at the same time. ^If SQLite is compiled with
1410 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1411 ** it is not possible to set the Multi-thread [threading mode] and
1412 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1413 ** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
1414 **
1415 ** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt>
1416 ** <dd>There are no arguments to this option. ^This option sets the
1417 ** [threading mode] to Serialized. In other words, this option enables
1418 ** all mutexes including the recursive
1419 ** mutexes on [database connection] and [prepared statement] objects.
1420 ** In this mode (which is the default when SQLite is compiled with
1421 ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
1422 ** to [database connections] and [prepared statements] so that the
1423 ** application is free to use the same [database connection] or the
1424 ** same [prepared statement] in different threads at the same time.
1425 ** ^If SQLite is compiled with
1426 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1427 ** it is not possible to set the Serialized [threading mode] and
1428 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1429 ** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
1430 **
1431 ** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt>
1432 ** <dd> ^(This option takes a single argument which is a pointer to an
1433 ** instance of the [sqlite3_mem_methods] structure. The argument specifies
1434 ** alternative low-level memory allocation routines to be used in place of
1435 ** the memory allocation routines built into SQLite.)^ ^SQLite makes
1436 ** its own private copy of the content of the [sqlite3_mem_methods] structure
1437 ** before the [sqlite3_config()] call returns.</dd>
1438 **
1439 ** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt>
1440 ** <dd> ^(This option takes a single argument which is a pointer to an
1441 ** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods]
1442 ** structure is filled with the currently defined memory allocation routines.)^
1443 ** This option can be used to overload the default memory allocation
1444 ** routines with a wrapper that simulations memory allocation failure or
1445 ** tracks memory usage, for example. </dd>
1446 **
1447 ** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt>
1448 ** <dd> ^This option takes single argument of type int, interpreted as a
1449 ** boolean, which enables or disables the collection of memory allocation
1450 ** statistics. ^(When memory allocation statistics are disabled, the
1451 ** following SQLite interfaces become non-operational:
1452 ** <ul>
1453 ** <li> [sqlite3_memory_used()]
1454 ** <li> [sqlite3_memory_highwater()]
1455 ** <li> [sqlite3_soft_heap_limit64()]
1456 ** <li> [sqlite3_status()]
1457 ** </ul>)^
1458 ** ^Memory allocation statistics are enabled by default unless SQLite is
1459 ** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
1460 ** allocation statistics are disabled by default.
1461 ** </dd>
1462 **
1463 ** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt>
1464 ** <dd> ^This option specifies a static memory buffer that SQLite can use for
1465 ** scratch memory. There are three arguments: A pointer an 8-byte
1466 ** aligned memory buffer from which the scratch allocations will be
1467 ** drawn, the size of each scratch allocation (sz),
1468 ** and the maximum number of scratch allocations (N). The sz
1469 ** argument must be a multiple of 16.
1470 ** The first argument must be a pointer to an 8-byte aligned buffer
1471 ** of at least sz*N bytes of memory.
1472 ** ^SQLite will use no more than two scratch buffers per thread. So
1473 ** N should be set to twice the expected maximum number of threads.
1474 ** ^SQLite will never require a scratch buffer that is more than 6
1475 ** times the database page size. ^If SQLite needs needs additional
1476 ** scratch memory beyond what is provided by this configuration option, then
1477 ** [sqlite3_malloc()] will be used to obtain the memory needed.</dd>
1478 **
1479 ** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>
1480 ** <dd> ^This option specifies a static memory buffer that SQLite can use for
1481 ** the database page cache with the default page cache implementation.
1482 ** This configuration should not be used if an application-define page
1483 ** cache implementation is loaded using the SQLITE_CONFIG_PCACHE2 option.
1484 ** There are three arguments to this option: A pointer to 8-byte aligned
1485 ** memory, the size of each page buffer (sz), and the number of pages (N).
1486 ** The sz argument should be the size of the largest database page
1487 ** (a power of two between 512 and 32768) plus a little extra for each
1488 ** page header. ^The page header size is 20 to 40 bytes depending on
1489 ** the host architecture. ^It is harmless, apart from the wasted memory,
1490 ** to make sz a little too large. The first
1491 ** argument should point to an allocation of at least sz*N bytes of memory.
1492 ** ^SQLite will use the memory provided by the first argument to satisfy its
1493 ** memory needs for the first N pages that it adds to cache. ^If additional
1494 ** page cache memory is needed beyond what is provided by this option, then
1495 ** SQLite goes to [sqlite3_malloc()] for the additional storage space.
1496 ** The pointer in the first argument must
1497 ** be aligned to an 8-byte boundary or subsequent behavior of SQLite
1498 ** will be undefined.</dd>
1499 **
1500 ** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt>
1501 ** <dd> ^This option specifies a static memory buffer that SQLite will use
1502 ** for all of its dynamic memory allocation needs beyond those provided
1503 ** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE].
1504 ** There are three arguments: An 8-byte aligned pointer to the memory,
1505 ** the number of bytes in the memory buffer, and the minimum allocation size.
1506 ** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
1507 ** to using its default memory allocator (the system malloc() implementation),
1508 ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the
1509 ** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or
1510 ** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory
1511 ** allocator is engaged to handle all of SQLites memory allocation needs.
1512 ** The first pointer (the memory pointer) must be aligned to an 8-byte
1513 ** boundary or subsequent behavior of SQLite will be undefined.
1514 ** The minimum allocation size is capped at 2**12. Reasonable values
1515 ** for the minimum allocation size are 2**5 through 2**8.</dd>
1516 **
1517 ** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt>
1518 ** <dd> ^(This option takes a single argument which is a pointer to an
1519 ** instance of the [sqlite3_mutex_methods] structure. The argument specifies
1520 ** alternative low-level mutex routines to be used in place
1521 ** the mutex routines built into SQLite.)^ ^SQLite makes a copy of the
1522 ** content of the [sqlite3_mutex_methods] structure before the call to
1523 ** [sqlite3_config()] returns. ^If SQLite is compiled with
1524 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1525 ** the entire mutexing subsystem is omitted from the build and hence calls to
1526 ** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
1527 ** return [SQLITE_ERROR].</dd>
1528 **
1529 ** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt>
1530 ** <dd> ^(This option takes a single argument which is a pointer to an
1531 ** instance of the [sqlite3_mutex_methods] structure. The
1532 ** [sqlite3_mutex_methods]
1533 ** structure is filled with the currently defined mutex routines.)^
1534 ** This option can be used to overload the default mutex allocation
1535 ** routines with a wrapper used to track mutex usage for performance
1536 ** profiling or testing, for example. ^If SQLite is compiled with
1537 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1538 ** the entire mutexing subsystem is omitted from the build and hence calls to
1539 ** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
1540 ** return [SQLITE_ERROR].</dd>
1541 **
1542 ** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt>
1543 ** <dd> ^(This option takes two arguments that determine the default
1544 ** memory allocation for the lookaside memory allocator on each
1545 ** [database connection]. The first argument is the
1546 ** size of each lookaside buffer slot and the second is the number of
1547 ** slots allocated to each database connection.)^ ^(This option sets the
1548 ** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
1549 ** verb to [sqlite3_db_config()] can be used to change the lookaside
1550 ** configuration on individual connections.)^ </dd>
1551 **
1552 ** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt>
1553 ** <dd> ^(This option takes a single argument which is a pointer to
1554 ** an [sqlite3_pcache_methods2] object. This object specifies the interface
1555 ** to a custom page cache implementation.)^ ^SQLite makes a copy of the
1556 ** object and uses it for page cache memory allocations.</dd>
1557 **
1558 ** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt>
1559 ** <dd> ^(This option takes a single argument which is a pointer to an
1560 ** [sqlite3_pcache_methods2] object. SQLite copies of the current
1561 ** page cache implementation into that object.)^ </dd>
1562 **
1563 ** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>
1564 ** <dd> ^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
1565 ** function with a call signature of void(*)(void*,int,const char*),
1566 ** and a pointer to void. ^If the function pointer is not NULL, it is
1567 ** invoked by [sqlite3_log()] to process each logging event. ^If the
1568 ** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
1569 ** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
1570 ** passed through as the first parameter to the application-defined logger
1571 ** function whenever that function is invoked. ^The second parameter to
1572 ** the logger function is a copy of the first parameter to the corresponding
1573 ** [sqlite3_log()] call and is intended to be a [result code] or an
1574 ** [extended result code]. ^The third parameter passed to the logger is
1575 ** log message after formatting via [sqlite3_snprintf()].
1576 ** The SQLite logging interface is not reentrant; the logger function
1577 ** supplied by the application must not invoke any SQLite interface.
1578 ** In a multi-threaded application, the application-defined logger
1579 ** function must be threadsafe. </dd>
1580 **
1581 ** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI
1582 ** <dd> This option takes a single argument of type int. If non-zero, then
1583 ** URI handling is globally enabled. If the parameter is zero, then URI handling
1584 ** is globally disabled. If URI handling is globally enabled, all filenames
1585 ** passed to [sqlite3_open()], [sqlite3_open_v2()], [sqlite3_open16()] or
1586 ** specified as part of [ATTACH] commands are interpreted as URIs, regardless
1587 ** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
1588 ** connection is opened. If it is globally disabled, filenames are
1589 ** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
1590 ** database connection is opened. By default, URI handling is globally
1591 ** disabled. The default value may be changed by compiling with the
1592 ** [SQLITE_USE_URI] symbol defined.
1593 **
1594 ** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN
1595 ** <dd> This option takes a single integer argument which is interpreted as
1596 ** a boolean in order to enable or disable the use of covering indices for
1597 ** full table scans in the query optimizer. The default setting is determined
1598 ** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on"
1599 ** if that compile-time option is omitted.
1600 ** The ability to disable the use of covering indices for full table scans
1601 ** is because some incorrectly coded legacy applications might malfunction
1602 ** malfunction when the optimization is enabled. Providing the ability to
1603 ** disable the optimization allows the older, buggy application code to work
1604 ** without change even with newer versions of SQLite.
1605 **
1606 ** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]]
1607 ** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE
1608 ** <dd> These options are obsolete and should not be used by new code.
1609 ** They are retained for backwards compatibility but are now no-ops.
1610 ** </dl>
1611 **
1612 ** [[SQLITE_CONFIG_SQLLOG]]
1613 ** <dt>SQLITE_CONFIG_SQLLOG
1614 ** <dd>This option is only available if sqlite is compiled with the
1615 ** SQLITE_ENABLE_SQLLOG pre-processor macro defined. The first argument should
1616 ** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int).
1617 ** The second should be of type (void*). The callback is invoked by the library
1618 ** in three separate circumstances, identified by the value passed as the
1619 ** fourth parameter. If the fourth parameter is 0, then the database connection
1620 ** passed as the second argument has just been opened. The third argument
1621 ** points to a buffer containing the name of the main database file. If the
1622 ** fourth parameter is 1, then the SQL statement that the third parameter
1623 ** points to has just been executed. Or, if the fourth parameter is 2, then
1624 ** the connection being passed as the second parameter is being closed. The
1625 ** third parameter is passed NULL In this case.
1626 ** </dl>
1627 */
1628 #define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */
1629 #define SQLITE_CONFIG_MULTITHREAD 2 /* nil */
1630 #define SQLITE_CONFIG_SERIALIZED 3 /* nil */
1631 #define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */
1632 #define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */
1633 #define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */
1634 #define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */
1635 #define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */
1636 #define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */
1637 #define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */
1638 #define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */
1639 /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */
1640 #define SQLITE_CONFIG_LOOKASIDE 13 /* int int */
1641 #define SQLITE_CONFIG_PCACHE 14 /* no-op */
1642 #define SQLITE_CONFIG_GETPCACHE 15 /* no-op */
1643 #define SQLITE_CONFIG_LOG 16 /* xFunc, void* */
1644 #define SQLITE_CONFIG_URI 17 /* int */
1645 #define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */
1646 #define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */
1647 #define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */
1648 #define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */
1649
1650 /*
1651 ** CAPI3REF: Database Connection Configuration Options
1652 **
1653 ** These constants are the available integer configuration options that
1654 ** can be passed as the second argument to the [sqlite3_db_config()] interface.
1655 **
1656 ** New configuration options may be added in future releases of SQLite.
1657 ** Existing configuration options might be discontinued. Applications
1658 ** should check the return code from [sqlite3_db_config()] to make sure that
1659 ** the call worked. ^The [sqlite3_db_config()] interface will return a
1660 ** non-zero [error code] if a discontinued or unsupported configuration option
1661 ** is invoked.
1662 **
1663 ** <dl>
1664 ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
1665 ** <dd> ^This option takes three additional arguments that determine the
1666 ** [lookaside memory allocator] configuration for the [database connection].
1667 ** ^The first argument (the third parameter to [sqlite3_db_config()] is a
1668 ** pointer to a memory buffer to use for lookaside memory.
1669 ** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
1670 ** may be NULL in which case SQLite will allocate the
1671 ** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
1672 ** size of each lookaside buffer slot. ^The third argument is the number of
1673 ** slots. The size of the buffer in the first argument must be greater than
1674 ** or equal to the product of the second and third arguments. The buffer
1675 ** must be aligned to an 8-byte boundary. ^If the second argument to
1676 ** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
1677 ** rounded down to the next smaller multiple of 8. ^(The lookaside memory
1678 ** configuration for a database connection can only be changed when that
1679 ** connection is not currently using lookaside memory, or in other words
1680 ** when the "current value" returned by
1681 ** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero.
1682 ** Any attempt to change the lookaside memory configuration when lookaside
1683 ** memory is in use leaves the configuration unchanged and returns
1684 ** [SQLITE_BUSY].)^</dd>
1685 **
1686 ** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
1687 ** <dd> ^This option is used to enable or disable the enforcement of
1688 ** [foreign key constraints]. There should be two additional arguments.
1689 ** The first argument is an integer which is 0 to disable FK enforcement,
1690 ** positive to enable FK enforcement or negative to leave FK enforcement
1691 ** unchanged. The second parameter is a pointer to an integer into which
1692 ** is written 0 or 1 to indicate whether FK enforcement is off or on
1693 ** following this call. The second parameter may be a NULL pointer, in
1694 ** which case the FK enforcement setting is not reported back. </dd>
1695 **
1696 ** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
1697 ** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
1698 ** There should be two additional arguments.
1699 ** The first argument is an integer which is 0 to disable triggers,
1700 ** positive to enable triggers or negative to leave the setting unchanged.
1701 ** The second parameter is a pointer to an integer into which
1702 ** is written 0 or 1 to indicate whether triggers are disabled or enabled
1703 ** following this call. The second parameter may be a NULL pointer, in
1704 ** which case the trigger setting is not reported back. </dd>
1705 **
1706 ** </dl>
1707 */
1708 #define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */
1709 #define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */
1710 #define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */
1711
1712
1713 /*
1714 ** CAPI3REF: Enable Or Disable Extended Result Codes
1715 **
1716 ** ^The sqlite3_extended_result_codes() routine enables or disables the
1717 ** [extended result codes] feature of SQLite. ^The extended result
1718 ** codes are disabled by default for historical compatibility.
1719 */
1720 SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff);
1721
1722 /*
1723 ** CAPI3REF: Last Insert Rowid
1724 **
1725 ** ^Each entry in an SQLite table has a unique 64-bit signed
1726 ** integer key called the [ROWID | "rowid"]. ^The rowid is always available
1727 ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
1728 ** names are not also used by explicitly declared columns. ^If
1729 ** the table has a column of type [INTEGER PRIMARY KEY] then that column
1730 ** is another alias for the rowid.
1731 **
1732 ** ^This routine returns the [rowid] of the most recent
1733 ** successful [INSERT] into the database from the [database connection]
1734 ** in the first argument. ^As of SQLite version 3.7.7, this routines
1735 ** records the last insert rowid of both ordinary tables and [virtual tables].
1736 ** ^If no successful [INSERT]s
1737 ** have ever occurred on that database connection, zero is returned.
1738 **
1739 ** ^(If an [INSERT] occurs within a trigger or within a [virtual table]
1740 ** method, then this routine will return the [rowid] of the inserted
1741 ** row as long as the trigger or virtual table method is running.
1742 ** But once the trigger or virtual table method ends, the value returned
1743 ** by this routine reverts to what it was before the trigger or virtual
1744 ** table method began.)^
1745 **
1746 ** ^An [INSERT] that fails due to a constraint violation is not a
1747 ** successful [INSERT] and does not change the value returned by this
1748 ** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
1749 ** and INSERT OR ABORT make no changes to the return value of this
1750 ** routine when their insertion fails. ^(When INSERT OR REPLACE
1751 ** encounters a constraint violation, it does not fail. The
1752 ** INSERT continues to completion after deleting rows that caused
1753 ** the constraint problem so INSERT OR REPLACE will always change
1754 ** the return value of this interface.)^
1755 **
1756 ** ^For the purposes of this routine, an [INSERT] is considered to
1757 ** be successful even if it is subsequently rolled back.
1758 **
1759 ** This function is accessible to SQL statements via the
1760 ** [last_insert_rowid() SQL function].
1761 **
1762 ** If a separate thread performs a new [INSERT] on the same
1763 ** database connection while the [sqlite3_last_insert_rowid()]
1764 ** function is running and thus changes the last insert [rowid],
1765 ** then the value returned by [sqlite3_last_insert_rowid()] is
1766 ** unpredictable and might not equal either the old or the new
1767 ** last insert [rowid].
1768 */
1769 SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
1770
1771 /*
1772 ** CAPI3REF: Count The Number Of Rows Modified
1773 **
1774 ** ^This function returns the number of database rows that were changed
1775 ** or inserted or deleted by the most recently completed SQL statement
1776 ** on the [database connection] specified by the first parameter.
1777 ** ^(Only changes that are directly specified by the [INSERT], [UPDATE],
1778 ** or [DELETE] statement are counted. Auxiliary changes caused by
1779 ** triggers or [foreign key actions] are not counted.)^ Use the
1780 ** [sqlite3_total_changes()] function to find the total number of changes
1781 ** including changes caused by triggers and foreign key actions.
1782 **
1783 ** ^Changes to a view that are simulated by an [INSTEAD OF trigger]
1784 ** are not counted. Only real table changes are counted.
1785 **
1786 ** ^(A "row change" is a change to a single row of a single table
1787 ** caused by an INSERT, DELETE, or UPDATE statement. Rows that
1788 ** are changed as side effects of [REPLACE] constraint resolution,
1789 ** rollback, ABORT processing, [DROP TABLE], or by any other
1790 ** mechanisms do not count as direct row changes.)^
1791 **
1792 ** A "trigger context" is a scope of execution that begins and
1793 ** ends with the script of a [CREATE TRIGGER | trigger].
1794 ** Most SQL statements are
1795 ** evaluated outside of any trigger. This is the "top level"
1796 ** trigger context. If a trigger fires from the top level, a
1797 ** new trigger context is entered for the duration of that one
1798 ** trigger. Subtriggers create subcontexts for their duration.
1799 **
1800 ** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does
1801 ** not create a new trigger context.
1802 **
1803 ** ^This function returns the number of direct row changes in the
1804 ** most recent INSERT, UPDATE, or DELETE statement within the same
1805 ** trigger context.
1806 **
1807 ** ^Thus, when called from the top level, this function returns the
1808 ** number of changes in the most recent INSERT, UPDATE, or DELETE
1809 ** that also occurred at the top level. ^(Within the body of a trigger,
1810 ** the sqlite3_changes() interface can be called to find the number of
1811 ** changes in the most recently completed INSERT, UPDATE, or DELETE
1812 ** statement within the body of the same trigger.
1813 ** However, the number returned does not include changes
1814 ** caused by subtriggers since those have their own context.)^
1815 **
1816 ** See also the [sqlite3_total_changes()] interface, the
1817 ** [count_changes pragma], and the [changes() SQL function].
1818 **
1819 ** If a separate thread makes changes on the same database connection
1820 ** while [sqlite3_changes()] is running then the value returned
1821 ** is unpredictable and not meaningful.
1822 */
1823 SQLITE_API int sqlite3_changes(sqlite3*);
1824
1825 /*
1826 ** CAPI3REF: Total Number Of Rows Modified
1827 **
1828 ** ^This function returns the number of row changes caused by [INSERT],
1829 ** [UPDATE] or [DELETE] statements since the [database connection] was opened.
1830 ** ^(The count returned by sqlite3_total_changes() includes all changes
1831 ** from all [CREATE TRIGGER | trigger] contexts and changes made by
1832 ** [foreign key actions]. However,
1833 ** the count does not include changes used to implement [REPLACE] constraints,
1834 ** do rollbacks or ABORT processing, or [DROP TABLE] processing. The
1835 ** count does not include rows of views that fire an [INSTEAD OF trigger],
1836 ** though if the INSTEAD OF trigger makes changes of its own, those changes
1837 ** are counted.)^
1838 ** ^The sqlite3_total_changes() function counts the changes as soon as
1839 ** the statement that makes them is completed (when the statement handle
1840 ** is passed to [sqlite3_reset()] or [sqlite3_finalize()]).
1841 **
1842 ** See also the [sqlite3_changes()] interface, the
1843 ** [count_changes pragma], and the [total_changes() SQL function].
1844 **
1845 ** If a separate thread makes changes on the same database connection
1846 ** while [sqlite3_total_changes()] is running then the value
1847 ** returned is unpredictable and not meaningful.
1848 */
1849 SQLITE_API int sqlite3_total_changes(sqlite3*);
1850
1851 /*
1852 ** CAPI3REF: Interrupt A Long-Running Query
1853 **
1854 ** ^This function causes any pending database operation to abort and
1855 ** return at its earliest opportunity. This routine is typically
1856 ** called in response to a user action such as pressing "Cancel"
1857 ** or Ctrl-C where the user wants a long query operation to halt
1858 ** immediately.
1859 **
1860 ** ^It is safe to call this routine from a thread different from the
1861 ** thread that is currently running the database operation. But it
1862 ** is not safe to call this routine with a [database connection] that
1863 ** is closed or might close before sqlite3_interrupt() returns.
1864 **
1865 ** ^If an SQL operation is very nearly finished at the time when
1866 ** sqlite3_interrupt() is called, then it might not have an opportunity
1867 ** to be interrupted and might continue to completion.
1868 **
1869 ** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
1870 ** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
1871 ** that is inside an explicit transaction, then the entire transaction
1872 ** will be rolled back automatically.
1873 **
1874 ** ^The sqlite3_interrupt(D) call is in effect until all currently running
1875 ** SQL statements on [database connection] D complete. ^Any new SQL statements
1876 ** that are started after the sqlite3_interrupt() call and before the
1877 ** running statements reaches zero are interrupted as if they had been
1878 ** running prior to the sqlite3_interrupt() call. ^New SQL statements
1879 ** that are started after the running statement count reaches zero are
1880 ** not effected by the sqlite3_interrupt().
1881 ** ^A call to sqlite3_interrupt(D) that occurs when there are no running
1882 ** SQL statements is a no-op and has no effect on SQL statements
1883 ** that are started after the sqlite3_interrupt() call returns.
1884 **
1885 ** If the database connection closes while [sqlite3_interrupt()]
1886 ** is running then bad things will likely happen.
1887 */
1888 SQLITE_API void sqlite3_interrupt(sqlite3*);
1889
1890 /*
1891 ** CAPI3REF: Determine If An SQL Statement Is Complete
1892 **
1893 ** These routines are useful during command-line input to determine if the
1894 ** currently entered text seems to form a complete SQL statement or
1895 ** if additional input is needed before sending the text into
1896 ** SQLite for parsing. ^These routines return 1 if the input string
1897 ** appears to be a complete SQL statement. ^A statement is judged to be
1898 ** complete if it ends with a semicolon token and is not a prefix of a
1899 ** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within
1900 ** string literals or quoted identifier names or comments are not
1901 ** independent tokens (they are part of the token in which they are
1902 ** embedded) and thus do not count as a statement terminator. ^Whitespace
1903 ** and comments that follow the final semicolon are ignored.
1904 **
1905 ** ^These routines return 0 if the statement is incomplete. ^If a
1906 ** memory allocation fails, then SQLITE_NOMEM is returned.
1907 **
1908 ** ^These routines do not parse the SQL statements thus
1909 ** will not detect syntactically incorrect SQL.
1910 **
1911 ** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior
1912 ** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
1913 ** automatically by sqlite3_complete16(). If that initialization fails,
1914 ** then the return value from sqlite3_complete16() will be non-zero
1915 ** regardless of whether or not the input SQL is complete.)^
1916 **
1917 ** The input to [sqlite3_complete()] must be a zero-terminated
1918 ** UTF-8 string.
1919 **
1920 ** The input to [sqlite3_complete16()] must be a zero-terminated
1921 ** UTF-16 string in native byte order.
1922 */
1923 SQLITE_API int sqlite3_complete(const char *sql);
1924 SQLITE_API int sqlite3_complete16(const void *sql);
1925
1926 /*
1927 ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
1928 **
1929 ** ^This routine sets a callback function that might be invoked whenever
1930 ** an attempt is made to open a database table that another thread
1931 ** or process has locked.
1932 **
1933 ** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]
1934 ** is returned immediately upon encountering the lock. ^If the busy callback
1935 ** is not NULL, then the callback might be invoked with two arguments.
1936 **
1937 ** ^The first argument to the busy handler is a copy of the void* pointer which
1938 ** is the third argument to sqlite3_busy_handler(). ^The second argument to
1939 ** the busy handler callback is the number of times that the busy handler has
1940 ** been invoked for this locking event. ^If the
1941 ** busy callback returns 0, then no additional attempts are made to
1942 ** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned.
1943 ** ^If the callback returns non-zero, then another attempt
1944 ** is made to open the database for reading and the cycle repeats.
1945 **
1946 ** The presence of a busy handler does not guarantee that it will be invoked
1947 ** when there is lock contention. ^If SQLite determines that invoking the busy
1948 ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
1949 ** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler.
1950 ** Consider a scenario where one process is holding a read lock that
1951 ** it is trying to promote to a reserved lock and
1952 ** a second process is holding a reserved lock that it is trying
1953 ** to promote to an exclusive lock. The first process cannot proceed
1954 ** because it is blocked by the second and the second process cannot
1955 ** proceed because it is blocked by the first. If both processes
1956 ** invoke the busy handlers, neither will make any progress. Therefore,
1957 ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
1958 ** will induce the first process to release its read lock and allow
1959 ** the second process to proceed.
1960 **
1961 ** ^The default busy callback is NULL.
1962 **
1963 ** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED]
1964 ** when SQLite is in the middle of a large transaction where all the
1965 ** changes will not fit into the in-memory cache. SQLite will
1966 ** already hold a RESERVED lock on the database file, but it needs
1967 ** to promote this lock to EXCLUSIVE so that it can spill cache
1968 ** pages into the database file without harm to concurrent
1969 ** readers. ^If it is unable to promote the lock, then the in-memory
1970 ** cache will be left in an inconsistent state and so the error
1971 ** code is promoted from the relatively benign [SQLITE_BUSY] to
1972 ** the more severe [SQLITE_IOERR_BLOCKED]. ^This error code promotion
1973 ** forces an automatic rollback of the changes. See the
1974 ** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError">
1975 ** CorruptionFollowingBusyError</a> wiki page for a discussion of why
1976 ** this is important.
1977 **
1978 ** ^(There can only be a single busy handler defined for each
1979 ** [database connection]. Setting a new busy handler clears any
1980 ** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()]
1981 ** will also set or clear the busy handler.
1982 **
1983 ** The busy callback should not take any actions which modify the
1984 ** database connection that invoked the busy handler. Any such actions
1985 ** result in undefined behavior.
1986 **
1987 ** A busy handler must not close the database connection
1988 ** or [prepared statement] that invoked the busy handler.
1989 */
1990 SQLITE_API int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*);
1991
1992 /*
1993 ** CAPI3REF: Set A Busy Timeout
1994 **
1995 ** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
1996 ** for a specified amount of time when a table is locked. ^The handler
1997 ** will sleep multiple times until at least "ms" milliseconds of sleeping
1998 ** have accumulated. ^After at least "ms" milliseconds of sleeping,
1999 ** the handler returns 0 which causes [sqlite3_step()] to return
2000 ** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED].
2001 **
2002 ** ^Calling this routine with an argument less than or equal to zero
2003 ** turns off all busy handlers.
2004 **
2005 ** ^(There can only be a single busy handler for a particular
2006 ** [database connection] any any given moment. If another busy handler
2007 ** was defined (using [sqlite3_busy_handler()]) prior to calling
2008 ** this routine, that other busy handler is cleared.)^
2009 */
2010 SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms);
2011
2012 /*
2013 ** CAPI3REF: Convenience Routines For Running Queries
2014 **
2015 ** This is a legacy interface that is preserved for backwards compatibility.
2016 ** Use of this interface is not recommended.
2017 **
2018 ** Definition: A <b>result table</b> is memory data structure created by the
2019 ** [sqlite3_get_table()] interface. A result table records the
2020 ** complete query results from one or more queries.
2021 **
2022 ** The table conceptually has a number of rows and columns. But
2023 ** these numbers are not part of the result table itself. These
2024 ** numbers are obtained separately. Let N be the number of rows
2025 ** and M be the number of columns.
2026 **
2027 ** A result table is an array of pointers to zero-terminated UTF-8 strings.
2028 ** There are (N+1)*M elements in the array. The first M pointers point
2029 ** to zero-terminated strings that contain the names of the columns.
2030 ** The remaining entries all point to query results. NULL values result
2031 ** in NULL pointers. All other values are in their UTF-8 zero-terminated
2032 ** string representation as returned by [sqlite3_column_text()].
2033 **
2034 ** A result table might consist of one or more memory allocations.
2035 ** It is not safe to pass a result table directly to [sqlite3_free()].
2036 ** A result table should be deallocated using [sqlite3_free_table()].
2037 **
2038 ** ^(As an example of the result table format, suppose a query result
2039 ** is as follows:
2040 **
2041 ** <blockquote><pre>
2042 ** Name | Age
2043 ** -----------------------
2044 ** Alice | 43
2045 ** Bob | 28
2046 ** Cindy | 21
2047 ** </pre></blockquote>
2048 **
2049 ** There are two column (M==2) and three rows (N==3). Thus the
2050 ** result table has 8 entries. Suppose the result table is stored
2051 ** in an array names azResult. Then azResult holds this content:
2052 **
2053 ** <blockquote><pre>
2054 ** azResult&#91;0] = "Name";
2055 ** azResult&#91;1] = "Age";
2056 ** azResult&#91;2] = "Alice";
2057 ** azResult&#91;3] = "43";
2058 ** azResult&#91;4] = "Bob";
2059 ** azResult&#91;5] = "28";
2060 ** azResult&#91;6] = "Cindy";
2061 ** azResult&#91;7] = "21";
2062 ** </pre></blockquote>)^
2063 **
2064 ** ^The sqlite3_get_table() function evaluates one or more
2065 ** semicolon-separated SQL statements in the zero-terminated UTF-8
2066 ** string of its 2nd parameter and returns a result table to the
2067 ** pointer given in its 3rd parameter.
2068 **
2069 ** After the application has finished with the result from sqlite3_get_table(),
2070 ** it must pass the result table pointer to sqlite3_free_table() in order to
2071 ** release the memory that was malloced. Because of the way the
2072 ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
2073 ** function must not try to call [sqlite3_free()] directly. Only
2074 ** [sqlite3_free_table()] is able to release the memory properly and safely.
2075 **
2076 ** The sqlite3_get_table() interface is implemented as a wrapper around
2077 ** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access
2078 ** to any internal data structures of SQLite. It uses only the public
2079 ** interface defined here. As a consequence, errors that occur in the
2080 ** wrapper layer outside of the internal [sqlite3_exec()] call are not
2081 ** reflected in subsequent calls to [sqlite3_errcode()] or
2082 ** [sqlite3_errmsg()].
2083 */
2084 SQLITE_API int sqlite3_get_table(
2085 sqlite3 *db, /* An open database */
2086 const char *zSql, /* SQL to be evaluated */
2087 char ***pazResult, /* Results of the query */
2088 int *pnRow, /* Number of result rows written here */
2089 int *pnColumn, /* Number of result columns written here */
2090 char **pzErrmsg /* Error msg written here */
2091 );
2092 SQLITE_API void sqlite3_free_table(char **result);
2093
2094 /*
2095 ** CAPI3REF: Formatted String Printing Functions
2096 **
2097 ** These routines are work-alikes of the "printf()" family of functions
2098 ** from the standard C library.
2099 **
2100 ** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
2101 ** results into memory obtained from [sqlite3_malloc()].
2102 ** The strings returned by these two routines should be
2103 ** released by [sqlite3_free()]. ^Both routines return a
2104 ** NULL pointer if [sqlite3_malloc()] is unable to allocate enough
2105 ** memory to hold the resulting string.
2106 **
2107 ** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
2108 ** the standard C library. The result is written into the
2109 ** buffer supplied as the second parameter whose size is given by
2110 ** the first parameter. Note that the order of the
2111 ** first two parameters is reversed from snprintf().)^ This is an
2112 ** historical accident that cannot be fixed without breaking
2113 ** backwards compatibility. ^(Note also that sqlite3_snprintf()
2114 ** returns a pointer to its buffer instead of the number of
2115 ** characters actually written into the buffer.)^ We admit that
2116 ** the number of characters written would be a more useful return
2117 ** value but we cannot change the implementation of sqlite3_snprintf()
2118 ** now without breaking compatibility.
2119 **
2120 ** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
2121 ** guarantees that the buffer is always zero-terminated. ^The first
2122 ** parameter "n" is the total size of the buffer, including space for
2123 ** the zero terminator. So the longest string that can be completely
2124 ** written will be n-1 characters.
2125 **
2126 ** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
2127 **
2128 ** These routines all implement some additional formatting
2129 ** options that are useful for constructing SQL statements.
2130 ** All of the usual printf() formatting options apply. In addition, there
2131 ** is are "%q", "%Q", and "%z" options.
2132 **
2133 ** ^(The %q option works like %s in that it substitutes a nul-terminated
2134 ** string from the argument list. But %q also doubles every '\'' character.
2135 ** %q is designed for use inside a string literal.)^ By doubling each '\''
2136 ** character it escapes that character and allows it to be inserted into
2137 ** the string.
2138 **
2139 ** For example, assume the string variable zText contains text as follows:
2140 **
2141 ** <blockquote><pre>
2142 ** char *zText = "It's a happy day!";
2143 ** </pre></blockquote>
2144 **
2145 ** One can use this text in an SQL statement as follows:
2146 **
2147 ** <blockquote><pre>
2148 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText);
2149 ** sqlite3_exec(db, zSQL, 0, 0, 0);
2150 ** sqlite3_free(zSQL);
2151 ** </pre></blockquote>
2152 **
2153 ** Because the %q format string is used, the '\'' character in zText
2154 ** is escaped and the SQL generated is as follows:
2155 **
2156 ** <blockquote><pre>
2157 ** INSERT INTO table1 VALUES('It''s a happy day!')
2158 ** </pre></blockquote>
2159 **
2160 ** This is correct. Had we used %s instead of %q, the generated SQL
2161 ** would have looked like this:
2162 **
2163 ** <blockquote><pre>
2164 ** INSERT INTO table1 VALUES('It's a happy day!');
2165 ** </pre></blockquote>
2166 **
2167 ** This second example is an SQL syntax error. As a general rule you should
2168 ** always use %q instead of %s when inserting text into a string literal.
2169 **
2170 ** ^(The %Q option works like %q except it also adds single quotes around
2171 ** the outside of the total string. Additionally, if the parameter in the
2172 ** argument list is a NULL pointer, %Q substitutes the text "NULL" (without
2173 ** single quotes).)^ So, for example, one could say:
2174 **
2175 ** <blockquote><pre>
2176 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText);
2177 ** sqlite3_exec(db, zSQL, 0, 0, 0);
2178 ** sqlite3_free(zSQL);
2179 ** </pre></blockquote>
2180 **
2181 ** The code above will render a correct SQL statement in the zSQL
2182 ** variable even if the zText variable is a NULL pointer.
2183 **
2184 ** ^(The "%z" formatting option works like "%s" but with the
2185 ** addition that after the string has been read and copied into
2186 ** the result, [sqlite3_free()] is called on the input string.)^
2187 */
2188 SQLITE_API char *sqlite3_mprintf(const char*,...);
2189 SQLITE_API char *sqlite3_vmprintf(const char*, va_list);
2190 SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...);
2191 SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list);
2192
2193 /*
2194 ** CAPI3REF: Memory Allocation Subsystem
2195 **
2196 ** The SQLite core uses these three routines for all of its own
2197 ** internal memory allocation needs. "Core" in the previous sentence
2198 ** does not include operating-system specific VFS implementation. The
2199 ** Windows VFS uses native malloc() and free() for some operations.
2200 **
2201 ** ^The sqlite3_malloc() routine returns a pointer to a block
2202 ** of memory at least N bytes in length, where N is the parameter.
2203 ** ^If sqlite3_malloc() is unable to obtain sufficient free
2204 ** memory, it returns a NULL pointer. ^If the parameter N to
2205 ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
2206 ** a NULL pointer.
2207 **
2208 ** ^Calling sqlite3_free() with a pointer previously returned
2209 ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
2210 ** that it might be reused. ^The sqlite3_free() routine is
2211 ** a no-op if is called with a NULL pointer. Passing a NULL pointer
2212 ** to sqlite3_free() is harmless. After being freed, memory
2213 ** should neither be read nor written. Even reading previously freed
2214 ** memory might result in a segmentation fault or other severe error.
2215 ** Memory corruption, a segmentation fault, or other severe error
2216 ** might result if sqlite3_free() is called with a non-NULL pointer that
2217 ** was not obtained from sqlite3_malloc() or sqlite3_realloc().
2218 **
2219 ** ^(The sqlite3_realloc() interface attempts to resize a
2220 ** prior memory allocation to be at least N bytes, where N is the
2221 ** second parameter. The memory allocation to be resized is the first
2222 ** parameter.)^ ^ If the first parameter to sqlite3_realloc()
2223 ** is a NULL pointer then its behavior is identical to calling
2224 ** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc().
2225 ** ^If the second parameter to sqlite3_realloc() is zero or
2226 ** negative then the behavior is exactly the same as calling
2227 ** sqlite3_free(P) where P is the first parameter to sqlite3_realloc().
2228 ** ^sqlite3_realloc() returns a pointer to a memory allocation
2229 ** of at least N bytes in size or NULL if sufficient memory is unavailable.
2230 ** ^If M is the size of the prior allocation, then min(N,M) bytes
2231 ** of the prior allocation are copied into the beginning of buffer returned
2232 ** by sqlite3_realloc() and the prior allocation is freed.
2233 ** ^If sqlite3_realloc() returns NULL, then the prior allocation
2234 ** is not freed.
2235 **
2236 ** ^The memory returned by sqlite3_malloc() and sqlite3_realloc()
2237 ** is always aligned to at least an 8 byte boundary, or to a
2238 ** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
2239 ** option is used.
2240 **
2241 ** In SQLite version 3.5.0 and 3.5.1, it was possible to define
2242 ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in
2243 ** implementation of these routines to be omitted. That capability
2244 ** is no longer provided. Only built-in memory allocators can be used.
2245 **
2246 ** Prior to SQLite version 3.7.10, the Windows OS interface layer called
2247 ** the system malloc() and free() directly when converting
2248 ** filenames between the UTF-8 encoding used by SQLite
2249 ** and whatever filename encoding is used by the particular Windows
2250 ** installation. Memory allocation errors were detected, but
2251 ** they were reported back as [SQLITE_CANTOPEN] or
2252 ** [SQLITE_IOERR] rather than [SQLITE_NOMEM].
2253 **
2254 ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
2255 ** must be either NULL or else pointers obtained from a prior
2256 ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
2257 ** not yet been released.
2258 **
2259 ** The application must not read or write any part of
2260 ** a block of memory after it has been released using
2261 ** [sqlite3_free()] or [sqlite3_realloc()].
2262 */
2263 SQLITE_API void *sqlite3_malloc(int);
2264 SQLITE_API void *sqlite3_realloc(void*, int);
2265 SQLITE_API void sqlite3_free(void*);
2266
2267 /*
2268 ** CAPI3REF: Memory Allocator Statistics
2269 **
2270 ** SQLite provides these two interfaces for reporting on the status
2271 ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
2272 ** routines, which form the built-in memory allocation subsystem.
2273 **
2274 ** ^The [sqlite3_memory_used()] routine returns the number of bytes
2275 ** of memory currently outstanding (malloced but not freed).
2276 ** ^The [sqlite3_memory_highwater()] routine returns the maximum
2277 ** value of [sqlite3_memory_used()] since the high-water mark
2278 ** was last reset. ^The values returned by [sqlite3_memory_used()] and
2279 ** [sqlite3_memory_highwater()] include any overhead
2280 ** added by SQLite in its implementation of [sqlite3_malloc()],
2281 ** but not overhead added by the any underlying system library
2282 ** routines that [sqlite3_malloc()] may call.
2283 **
2284 ** ^The memory high-water mark is reset to the current value of
2285 ** [sqlite3_memory_used()] if and only if the parameter to
2286 ** [sqlite3_memory_highwater()] is true. ^The value returned
2287 ** by [sqlite3_memory_highwater(1)] is the high-water mark
2288 ** prior to the reset.
2289 */
2290 SQLITE_API sqlite3_int64 sqlite3_memory_used(void);
2291 SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
2292
2293 /*
2294 ** CAPI3REF: Pseudo-Random Number Generator
2295 **
2296 ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
2297 ** select random [ROWID | ROWIDs] when inserting new records into a table that
2298 ** already uses the largest possible [ROWID]. The PRNG is also used for
2299 ** the build-in random() and randomblob() SQL functions. This interface allows
2300 ** applications to access the same PRNG for other purposes.
2301 **
2302 ** ^A call to this routine stores N bytes of randomness into buffer P.
2303 **
2304 ** ^The first time this routine is invoked (either internally or by
2305 ** the application) the PRNG is seeded using randomness obtained
2306 ** from the xRandomness method of the default [sqlite3_vfs] object.
2307 ** ^On all subsequent invocations, the pseudo-randomness is generated
2308 ** internally and without recourse to the [sqlite3_vfs] xRandomness
2309 ** method.
2310 */
2311 SQLITE_API void sqlite3_randomness(int N, void *P);
2312
2313 /*
2314 ** CAPI3REF: Compile-Time Authorization Callbacks
2315 **
2316 ** ^This routine registers an authorizer callback with a particular
2317 ** [database connection], supplied in the first argument.
2318 ** ^The authorizer callback is invoked as SQL statements are being compiled
2319 ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
2320 ** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various
2321 ** points during the compilation process, as logic is being created
2322 ** to perform various actions, the authorizer callback is invoked to
2323 ** see if those actions are allowed. ^The authorizer callback should
2324 ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
2325 ** specific action but allow the SQL statement to continue to be
2326 ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
2327 ** rejected with an error. ^If the authorizer callback returns
2328 ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
2329 ** then the [sqlite3_prepare_v2()] or equivalent call that triggered
2330 ** the authorizer will fail with an error message.
2331 **
2332 ** When the callback returns [SQLITE_OK], that means the operation
2333 ** requested is ok. ^When the callback returns [SQLITE_DENY], the
2334 ** [sqlite3_prepare_v2()] or equivalent call that triggered the
2335 ** authorizer will fail with an error message explaining that
2336 ** access is denied.
2337 **
2338 ** ^The first parameter to the authorizer callback is a copy of the third
2339 ** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
2340 ** to the callback is an integer [SQLITE_COPY | action code] that specifies
2341 ** the particular action to be authorized. ^The third through sixth parameters
2342 ** to the callback are zero-terminated strings that contain additional
2343 ** details about the action to be authorized.
2344 **
2345 ** ^If the action code is [SQLITE_READ]
2346 ** and the callback returns [SQLITE_IGNORE] then the
2347 ** [prepared statement] statement is constructed to substitute
2348 ** a NULL value in place of the table column that would have
2349 ** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE]
2350 ** return can be used to deny an untrusted user access to individual
2351 ** columns of a table.
2352 ** ^If the action code is [SQLITE_DELETE] and the callback returns
2353 ** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
2354 ** [truncate optimization] is disabled and all rows are deleted individually.
2355 **
2356 ** An authorizer is used when [sqlite3_prepare | preparing]
2357 ** SQL statements from an untrusted source, to ensure that the SQL statements
2358 ** do not try to access data they are not allowed to see, or that they do not
2359 ** try to execute malicious statements that damage the database. For
2360 ** example, an application may allow a user to enter arbitrary
2361 ** SQL queries for evaluation by a database. But the application does
2362 ** not want the user to be able to make arbitrary changes to the
2363 ** database. An authorizer could then be put in place while the
2364 ** user-entered SQL is being [sqlite3_prepare | prepared] that
2365 ** disallows everything except [SELECT] statements.
2366 **
2367 ** Applications that need to process SQL from untrusted sources
2368 ** might also consider lowering resource limits using [sqlite3_limit()]
2369 ** and limiting database size using the [max_page_count] [PRAGMA]
2370 ** in addition to using an authorizer.
2371 **
2372 ** ^(Only a single authorizer can be in place on a database connection
2373 ** at a time. Each call to sqlite3_set_authorizer overrides the
2374 ** previous call.)^ ^Disable the authorizer by installing a NULL callback.
2375 ** The authorizer is disabled by default.
2376 **
2377 ** The authorizer callback must not do anything that will modify
2378 ** the database connection that invoked the authorizer callback.
2379 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2380 ** database connections for the meaning of "modify" in this paragraph.
2381 **
2382 ** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
2383 ** statement might be re-prepared during [sqlite3_step()] due to a
2384 ** schema change. Hence, the application should ensure that the
2385 ** correct authorizer callback remains in place during the [sqlite3_step()].
2386 **
2387 ** ^Note that the authorizer callback is invoked only during
2388 ** [sqlite3_prepare()] or its variants. Authorization is not
2389 ** performed during statement evaluation in [sqlite3_step()], unless
2390 ** as stated in the previous paragraph, sqlite3_step() invokes
2391 ** sqlite3_prepare_v2() to reprepare a statement after a schema change.
2392 */
2393 SQLITE_API int sqlite3_set_authorizer(
2394 sqlite3*,
2395 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
2396 void *pUserData
2397 );
2398
2399 /*
2400 ** CAPI3REF: Authorizer Return Codes
2401 **
2402 ** The [sqlite3_set_authorizer | authorizer callback function] must
2403 ** return either [SQLITE_OK] or one of these two constants in order
2404 ** to signal SQLite whether or not the action is permitted. See the
2405 ** [sqlite3_set_authorizer | authorizer documentation] for additional
2406 ** information.
2407 **
2408 ** Note that SQLITE_IGNORE is also used as a [SQLITE_ROLLBACK | return code]
2409 ** from the [sqlite3_vtab_on_conflict()] interface.
2410 */
2411 #define SQLITE_DENY 1 /* Abort the SQL statement with an error */
2412 #define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */
2413
2414 /*
2415 ** CAPI3REF: Authorizer Action Codes
2416 **
2417 ** The [sqlite3_set_authorizer()] interface registers a callback function
2418 ** that is invoked to authorize certain SQL statement actions. The
2419 ** second parameter to the callback is an integer code that specifies
2420 ** what action is being authorized. These are the integer action codes that
2421 ** the authorizer callback may be passed.
2422 **
2423 ** These action code values signify what kind of operation is to be
2424 ** authorized. The 3rd and 4th parameters to the authorization
2425 ** callback function will be parameters or NULL depending on which of these
2426 ** codes is used as the second parameter. ^(The 5th parameter to the
2427 ** authorizer callback is the name of the database ("main", "temp",
2428 ** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback
2429 ** is the name of the inner-most trigger or view that is responsible for
2430 ** the access attempt or NULL if this access attempt is directly from
2431 ** top-level SQL code.
2432 */
2433 /******************************************* 3rd ************ 4th ***********/
2434 #define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */
2435 #define SQLITE_CREATE_TABLE 2 /* Table Name NULL */
2436 #define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */
2437 #define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */
2438 #define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */
2439 #define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */
2440 #define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */
2441 #define SQLITE_CREATE_VIEW 8 /* View Name NULL */
2442 #define SQLITE_DELETE 9 /* Table Name NULL */
2443 #define SQLITE_DROP_INDEX 10 /* Index Name Table Name */
2444 #define SQLITE_DROP_TABLE 11 /* Table Name NULL */
2445 #define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */
2446 #define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */
2447 #define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */
2448 #define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */
2449 #define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */
2450 #define SQLITE_DROP_VIEW 17 /* View Name NULL */
2451 #define SQLITE_INSERT 18 /* Table Name NULL */
2452 #define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */
2453 #define SQLITE_READ 20 /* Table Name Column Name */
2454 #define SQLITE_SELECT 21 /* NULL NULL */
2455 #define SQLITE_TRANSACTION 22 /* Operation NULL */
2456 #define SQLITE_UPDATE 23 /* Table Name Column Name */
2457 #define SQLITE_ATTACH 24 /* Filename NULL */
2458 #define SQLITE_DETACH 25 /* Database Name NULL */
2459 #define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */
2460 #define SQLITE_REINDEX 27 /* Index Name NULL */
2461 #define SQLITE_ANALYZE 28 /* Table Name NULL */
2462 #define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */
2463 #define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */
2464 #define SQLITE_FUNCTION 31 /* NULL Function Name */
2465 #define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */
2466 #define SQLITE_COPY 0 /* No longer used */
2467
2468 /*
2469 ** CAPI3REF: Tracing And Profiling Functions
2470 **
2471 ** These routines register callback functions that can be used for
2472 ** tracing and profiling the execution of SQL statements.
2473 **
2474 ** ^The callback function registered by sqlite3_trace() is invoked at
2475 ** various times when an SQL statement is being run by [sqlite3_step()].
2476 ** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
2477 ** SQL statement text as the statement first begins executing.
2478 ** ^(Additional sqlite3_trace() callbacks might occur
2479 ** as each triggered subprogram is entered. The callbacks for triggers
2480 ** contain a UTF-8 SQL comment that identifies the trigger.)^
2481 **
2482 ** ^The callback function registered by sqlite3_profile() is invoked
2483 ** as each SQL statement finishes. ^The profile callback contains
2484 ** the original statement text and an estimate of wall-clock time
2485 ** of how long that statement took to run. ^The profile callback
2486 ** time is in units of nanoseconds, however the current implementation
2487 ** is only capable of millisecond resolution so the six least significant
2488 ** digits in the time are meaningless. Future versions of SQLite
2489 ** might provide greater resolution on the profiler callback. The
2490 ** sqlite3_profile() function is considered experimental and is
2491 ** subject to change in future versions of SQLite.
2492 */
2493 SQLITE_API void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*);
2494 SQLITE_API SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*,
2495 void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
2496
2497 /*
2498 ** CAPI3REF: Query Progress Callbacks
2499 **
2500 ** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
2501 ** function X to be invoked periodically during long running calls to
2502 ** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for
2503 ** database connection D. An example use for this
2504 ** interface is to keep a GUI updated during a large query.
2505 **
2506 ** ^The parameter P is passed through as the only parameter to the
2507 ** callback function X. ^The parameter N is the number of
2508 ** [virtual machine instructions] that are evaluated between successive
2509 ** invocations of the callback X.
2510 **
2511 ** ^Only a single progress handler may be defined at one time per
2512 ** [database connection]; setting a new progress handler cancels the
2513 ** old one. ^Setting parameter X to NULL disables the progress handler.
2514 ** ^The progress handler is also disabled by setting N to a value less
2515 ** than 1.
2516 **
2517 ** ^If the progress callback returns non-zero, the operation is
2518 ** interrupted. This feature can be used to implement a
2519 ** "Cancel" button on a GUI progress dialog box.
2520 **
2521 ** The progress handler callback must not do anything that will modify
2522 ** the database connection that invoked the progress handler.
2523 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2524 ** database connections for the meaning of "modify" in this paragraph.
2525 **
2526 */
2527 SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
2528
2529 /*
2530 ** CAPI3REF: Opening A New Database Connection
2531 **
2532 ** ^These routines open an SQLite database file as specified by the
2533 ** filename argument. ^The filename argument is interpreted as UTF-8 for
2534 ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
2535 ** order for sqlite3_open16(). ^(A [database connection] handle is usually
2536 ** returned in *ppDb, even if an error occurs. The only exception is that
2537 ** if SQLite is unable to allocate memory to hold the [sqlite3] object,
2538 ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
2539 ** object.)^ ^(If the database is opened (and/or created) successfully, then
2540 ** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The
2541 ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
2542 ** an English language description of the error following a failure of any
2543 ** of the sqlite3_open() routines.
2544 **
2545 ** ^The default encoding for the database will be UTF-8 if
2546 ** sqlite3_open() or sqlite3_open_v2() is called and
2547 ** UTF-16 in the native byte order if sqlite3_open16() is used.
2548 **
2549 ** Whether or not an error occurs when it is opened, resources
2550 ** associated with the [database connection] handle should be released by
2551 ** passing it to [sqlite3_close()] when it is no longer required.
2552 **
2553 ** The sqlite3_open_v2() interface works like sqlite3_open()
2554 ** except that it accepts two additional parameters for additional control
2555 ** over the new database connection. ^(The flags parameter to
2556 ** sqlite3_open_v2() can take one of
2557 ** the following three values, optionally combined with the
2558 ** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE],
2559 ** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^
2560 **
2561 ** <dl>
2562 ** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
2563 ** <dd>The database is opened in read-only mode. If the database does not
2564 ** already exist, an error is returned.</dd>)^
2565 **
2566 ** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
2567 ** <dd>The database is opened for reading and writing if possible, or reading
2568 ** only if the file is write protected by the operating system. In either
2569 ** case the database must already exist, otherwise an error is returned.</dd>)^
2570 **
2571 ** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
2572 ** <dd>The database is opened for reading and writing, and is created if
2573 ** it does not already exist. This is the behavior that is always used for
2574 ** sqlite3_open() and sqlite3_open16().</dd>)^
2575 ** </dl>
2576 **
2577 ** If the 3rd parameter to sqlite3_open_v2() is not one of the
2578 ** combinations shown above optionally combined with other
2579 ** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits]
2580 ** then the behavior is undefined.
2581 **
2582 ** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection
2583 ** opens in the multi-thread [threading mode] as long as the single-thread
2584 ** mode has not been set at compile-time or start-time. ^If the
2585 ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens
2586 ** in the serialized [threading mode] unless single-thread was
2587 ** previously selected at compile-time or start-time.
2588 ** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be
2589 ** eligible to use [shared cache mode], regardless of whether or not shared
2590 ** cache is enabled using [sqlite3_enable_shared_cache()]. ^The
2591 ** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not
2592 ** participate in [shared cache mode] even if it is enabled.
2593 **
2594 ** ^The fourth parameter to sqlite3_open_v2() is the name of the
2595 ** [sqlite3_vfs] object that defines the operating system interface that
2596 ** the new database connection should use. ^If the fourth parameter is
2597 ** a NULL pointer then the default [sqlite3_vfs] object is used.
2598 **
2599 ** ^If the filename is ":memory:", then a private, temporary in-memory database
2600 ** is created for the connection. ^This in-memory database will vanish when
2601 ** the database connection is closed. Future versions of SQLite might
2602 ** make use of additional special filenames that begin with the ":" character.
2603 ** It is recommended that when a database filename actually does begin with
2604 ** a ":" character you should prefix the filename with a pathname such as
2605 ** "./" to avoid ambiguity.
2606 **
2607 ** ^If the filename is an empty string, then a private, temporary
2608 ** on-disk database will be created. ^This private database will be
2609 ** automatically deleted as soon as the database connection is closed.
2610 **
2611 ** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
2612 **
2613 ** ^If [URI filename] interpretation is enabled, and the filename argument
2614 ** begins with "file:", then the filename is interpreted as a URI. ^URI
2615 ** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
2616 ** set in the fourth argument to sqlite3_open_v2(), or if it has
2617 ** been enabled globally using the [SQLITE_CONFIG_URI] option with the
2618 ** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
2619 ** As of SQLite version 3.7.7, URI filename interpretation is turned off
2620 ** by default, but future releases of SQLite might enable URI filename
2621 ** interpretation by default. See "[URI filenames]" for additional
2622 ** information.
2623 **
2624 ** URI filenames are parsed according to RFC 3986. ^If the URI contains an
2625 ** authority, then it must be either an empty string or the string
2626 ** "localhost". ^If the authority is not an empty string or "localhost", an
2627 ** error is returned to the caller. ^The fragment component of a URI, if
2628 ** present, is ignored.
2629 **
2630 ** ^SQLite uses the path component of the URI as the name of the disk file
2631 ** which contains the database. ^If the path begins with a '/' character,
2632 ** then it is interpreted as an absolute path. ^If the path does not begin
2633 ** with a '/' (meaning that the authority section is omitted from the URI)
2634 ** then the path is interpreted as a relative path.
2635 ** ^On windows, the first component of an absolute path
2636 ** is a drive specification (e.g. "C:").
2637 **
2638 ** [[core URI query parameters]]
2639 ** The query component of a URI may contain parameters that are interpreted
2640 ** either by SQLite itself, or by a [VFS | custom VFS implementation].
2641 ** SQLite interprets the following three query parameters:
2642 **
2643 ** <ul>
2644 ** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
2645 ** a VFS object that provides the operating system interface that should
2646 ** be used to access the database file on disk. ^If this option is set to
2647 ** an empty string the default VFS object is used. ^Specifying an unknown
2648 ** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
2649 ** present, then the VFS specified by the option takes precedence over
2650 ** the value passed as the fourth parameter to sqlite3_open_v2().
2651 **
2652 ** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw",
2653 ** "rwc", or "memory". Attempting to set it to any other value is
2654 ** an error)^.
2655 ** ^If "ro" is specified, then the database is opened for read-only
2656 ** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the
2657 ** third argument to sqlite3_open_v2(). ^If the mode option is set to
2658 ** "rw", then the database is opened for read-write (but not create)
2659 ** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had
2660 ** been set. ^Value "rwc" is equivalent to setting both
2661 ** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is
2662 ** set to "memory" then a pure [in-memory database] that never reads
2663 ** or writes from disk is used. ^It is an error to specify a value for
2664 ** the mode parameter that is less restrictive than that specified by
2665 ** the flags passed in the third parameter to sqlite3_open_v2().
2666 **
2667 ** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
2668 ** "private". ^Setting it to "shared" is equivalent to setting the
2669 ** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
2670 ** sqlite3_open_v2(). ^Setting the cache parameter to "private" is
2671 ** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
2672 ** ^If sqlite3_open_v2() is used and the "cache" parameter is present in
2673 ** a URI filename, its value overrides any behaviour requested by setting
2674 ** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.
2675 ** </ul>
2676 **
2677 ** ^Specifying an unknown parameter in the query component of a URI is not an
2678 ** error. Future versions of SQLite might understand additional query
2679 ** parameters. See "[query parameters with special meaning to SQLite]" for
2680 ** additional information.
2681 **
2682 ** [[URI filename examples]] <h3>URI filename examples</h3>
2683 **
2684 ** <table border="1" align=center cellpadding=5>
2685 ** <tr><th> URI filenames <th> Results
2686 ** <tr><td> file:data.db <td>
2687 ** Open the file "data.db" in the current directory.
2688 ** <tr><td> file:/home/fred/data.db<br>
2689 ** file:///home/fred/data.db <br>
2690 ** file://localhost/home/fred/data.db <br> <td>
2691 ** Open the database file "/home/fred/data.db".
2692 ** <tr><td> file://darkstar/home/fred/data.db <td>
2693 ** An error. "darkstar" is not a recognized authority.
2694 ** <tr><td style="white-space:nowrap">
2695 ** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
2696 ** <td> Windows only: Open the file "data.db" on fred's desktop on drive
2697 ** C:. Note that the %20 escaping in this example is not strictly
2698 ** necessary - space characters can be used literally
2699 ** in URI filenames.
2700 ** <tr><td> file:data.db?mode=ro&cache=private <td>
2701 ** Open file "data.db" in the current directory for read-only access.
2702 ** Regardless of whether or not shared-cache mode is enabled by
2703 ** default, use a private cache.
2704 ** <tr><td> file:/home/fred/data.db?vfs=unix-nolock <td>
2705 ** Open file "/home/fred/data.db". Use the special VFS "unix-nolock".
2706 ** <tr><td> file:data.db?mode=readonly <td>
2707 ** An error. "readonly" is not a valid option for the "mode" parameter.
2708 ** </table>
2709 **
2710 ** ^URI hexadecimal escape sequences (%HH) are supported within the path and
2711 ** query components of a URI. A hexadecimal escape sequence consists of a
2712 ** percent sign - "%" - followed by exactly two hexadecimal digits
2713 ** specifying an octet value. ^Before the path or query components of a
2714 ** URI filename are interpreted, they are encoded using UTF-8 and all
2715 ** hexadecimal escape sequences replaced by a single byte containing the
2716 ** corresponding octet. If this process generates an invalid UTF-8 encoding,
2717 ** the results are undefined.
2718 **
2719 ** <b>Note to Windows users:</b> The encoding used for the filename argument
2720 ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
2721 ** codepage is currently defined. Filenames containing international
2722 ** characters must be converted to UTF-8 prior to passing them into
2723 ** sqlite3_open() or sqlite3_open_v2().
2724 **
2725 ** <b>Note to Windows Runtime users:</b> The temporary directory must be set
2726 ** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various
2727 ** features that require the use of temporary files may fail.
2728 **
2729 ** See also: [sqlite3_temp_directory]
2730 */
2731 SQLITE_API int sqlite3_open(
2732 const char *filename, /* Database filename (UTF-8) */
2733 sqlite3 **ppDb /* OUT: SQLite db handle */
2734 );
2735 SQLITE_API int sqlite3_open16(
2736 const void *filename, /* Database filename (UTF-16) */
2737 sqlite3 **ppDb /* OUT: SQLite db handle */
2738 );
2739 SQLITE_API int sqlite3_open_v2(
2740 const char *filename, /* Database filename (UTF-8) */
2741 sqlite3 **ppDb, /* OUT: SQLite db handle */
2742 int flags, /* Flags */
2743 const char *zVfs /* Name of VFS module to use */
2744 );
2745
2746 /*
2747 ** CAPI3REF: Obtain Values For URI Parameters
2748 **
2749 ** These are utility routines, useful to VFS implementations, that check
2750 ** to see if a database file was a URI that contained a specific query
2751 ** parameter, and if so obtains the value of that query parameter.
2752 **
2753 ** If F is the database filename pointer passed into the xOpen() method of
2754 ** a VFS implementation when the flags parameter to xOpen() has one or
2755 ** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and
2756 ** P is the name of the query parameter, then
2757 ** sqlite3_uri_parameter(F,P) returns the value of the P
2758 ** parameter if it exists or a NULL pointer if P does not appear as a
2759 ** query parameter on F. If P is a query parameter of F
2760 ** has no explicit value, then sqlite3_uri_parameter(F,P) returns
2761 ** a pointer to an empty string.
2762 **
2763 ** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
2764 ** parameter and returns true (1) or false (0) according to the value
2765 ** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
2766 ** value of query parameter P is one of "yes", "true", or "on" in any
2767 ** case or if the value begins with a non-zero number. The
2768 ** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
2769 ** query parameter P is one of "no", "false", or "off" in any case or
2770 ** if the value begins with a numeric zero. If P is not a query
2771 ** parameter on F or if the value of P is does not match any of the
2772 ** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).
2773 **
2774 ** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
2775 ** 64-bit signed integer and returns that integer, or D if P does not
2776 ** exist. If the value of P is something other than an integer, then
2777 ** zero is returned.
2778 **
2779 ** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
2780 ** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and
2781 ** is not a database file pathname pointer that SQLite passed into the xOpen
2782 ** VFS method, then the behavior of this routine is undefined and probably
2783 ** undesirable.
2784 */
2785 SQLITE_API const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam);
2786 SQLITE_API int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault);
2787 SQLITE_API sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64);
2788
2789
2790 /*
2791 ** CAPI3REF: Error Codes And Messages
2792 **
2793 ** ^The sqlite3_errcode() interface returns the numeric [result code] or
2794 ** [extended result code] for the most recent failed sqlite3_* API call
2795 ** associated with a [database connection]. If a prior API call failed
2796 ** but the most recent API call succeeded, the return value from
2797 ** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode()
2798 ** interface is the same except that it always returns the
2799 ** [extended result code] even when extended result codes are
2800 ** disabled.
2801 **
2802 ** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
2803 ** text that describes the error, as either UTF-8 or UTF-16 respectively.
2804 ** ^(Memory to hold the error message string is managed internally.
2805 ** The application does not need to worry about freeing the result.
2806 ** However, the error string might be overwritten or deallocated by
2807 ** subsequent calls to other SQLite interface functions.)^
2808 **
2809 ** ^The sqlite3_errstr() interface returns the English-language text
2810 ** that describes the [result code], as UTF-8.
2811 ** ^(Memory to hold the error message string is managed internally
2812 ** and must not be freed by the application)^.
2813 **
2814 ** When the serialized [threading mode] is in use, it might be the
2815 ** case that a second error occurs on a separate thread in between
2816 ** the time of the first error and the call to these interfaces.
2817 ** When that happens, the second error will be reported since these
2818 ** interfaces always report the most recent result. To avoid
2819 ** this, each thread can obtain exclusive use of the [database connection] D
2820 ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
2821 ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
2822 ** all calls to the interfaces listed here are completed.
2823 **
2824 ** If an interface fails with SQLITE_MISUSE, that means the interface
2825 ** was invoked incorrectly by the application. In that case, the
2826 ** error code and message may or may not be set.
2827 */
2828 SQLITE_API int sqlite3_errcode(sqlite3 *db);
2829 SQLITE_API int sqlite3_extended_errcode(sqlite3 *db);
2830 SQLITE_API const char *sqlite3_errmsg(sqlite3*);
2831 SQLITE_API const void *sqlite3_errmsg16(sqlite3*);
2832 SQLITE_API const char *sqlite3_errstr(int);
2833
2834 /*
2835 ** CAPI3REF: SQL Statement Object
2836 ** KEYWORDS: {prepared statement} {prepared statements}
2837 **
2838 ** An instance of this object represents a single SQL statement.
2839 ** This object is variously known as a "prepared statement" or a
2840 ** "compiled SQL statement" or simply as a "statement".
2841 **
2842 ** The life of a statement object goes something like this:
2843 **
2844 ** <ol>
2845 ** <li> Create the object using [sqlite3_prepare_v2()] or a related
2846 ** function.
2847 ** <li> Bind values to [host parameters] using the sqlite3_bind_*()
2848 ** interfaces.
2849 ** <li> Run the SQL by calling [sqlite3_step()] one or more times.
2850 ** <li> Reset the statement using [sqlite3_reset()] then go back
2851 ** to step 2. Do this zero or more times.
2852 ** <li> Destroy the object using [sqlite3_finalize()].
2853 ** </ol>
2854 **
2855 ** Refer to documentation on individual methods above for additional
2856 ** information.
2857 */
2858 typedef struct sqlite3_stmt sqlite3_stmt;
2859
2860 /*
2861 ** CAPI3REF: Run-time Limits
2862 **
2863 ** ^(This interface allows the size of various constructs to be limited
2864 ** on a connection by connection basis. The first parameter is the
2865 ** [database connection] whose limit is to be set or queried. The
2866 ** second parameter is one of the [limit categories] that define a
2867 ** class of constructs to be size limited. The third parameter is the
2868 ** new limit for that construct.)^
2869 **
2870 ** ^If the new limit is a negative number, the limit is unchanged.
2871 ** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
2872 ** [limits | hard upper bound]
2873 ** set at compile-time by a C preprocessor macro called
2874 ** [limits | SQLITE_MAX_<i>NAME</i>].
2875 ** (The "_LIMIT_" in the name is changed to "_MAX_".))^
2876 ** ^Attempts to increase a limit above its hard upper bound are
2877 ** silently truncated to the hard upper bound.
2878 **
2879 ** ^Regardless of whether or not the limit was changed, the
2880 ** [sqlite3_limit()] interface returns the prior value of the limit.
2881 ** ^Hence, to find the current value of a limit without changing it,
2882 ** simply invoke this interface with the third parameter set to -1.
2883 **
2884 ** Run-time limits are intended for use in applications that manage
2885 ** both their own internal database and also databases that are controlled
2886 ** by untrusted external sources. An example application might be a
2887 ** web browser that has its own databases for storing history and
2888 ** separate databases controlled by JavaScript applications downloaded
2889 ** off the Internet. The internal databases can be given the
2890 ** large, default limits. Databases managed by external sources can
2891 ** be given much smaller limits designed to prevent a denial of service
2892 ** attack. Developers might also want to use the [sqlite3_set_authorizer()]
2893 ** interface to further control untrusted SQL. The size of the database
2894 ** created by an untrusted script can be contained using the
2895 ** [max_page_count] [PRAGMA].
2896 **
2897 ** New run-time limit categories may be added in future releases.
2898 */
2899 SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal);
2900
2901 /*
2902 ** CAPI3REF: Run-Time Limit Categories
2903 ** KEYWORDS: {limit category} {*limit categories}
2904 **
2905 ** These constants define various performance limits
2906 ** that can be lowered at run-time using [sqlite3_limit()].
2907 ** The synopsis of the meanings of the various limits is shown below.
2908 ** Additional information is available at [limits | Limits in SQLite].
2909 **
2910 ** <dl>
2911 ** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt>
2912 ** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
2913 **
2914 ** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
2915 ** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
2916 **
2917 ** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt>
2918 ** <dd>The maximum number of columns in a table definition or in the
2919 ** result set of a [SELECT] or the maximum number of columns in an index
2920 ** or in an ORDER BY or GROUP BY clause.</dd>)^
2921 **
2922 ** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
2923 ** <dd>The maximum depth of the parse tree on any expression.</dd>)^
2924 **
2925 ** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
2926 ** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
2927 **
2928 ** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
2929 ** <dd>The maximum number of instructions in a virtual machine program
2930 ** used to implement an SQL statement. This limit is not currently
2931 ** enforced, though that might be added in some future release of
2932 ** SQLite.</dd>)^
2933 **
2934 ** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
2935 ** <dd>The maximum number of arguments on a function.</dd>)^
2936 **
2937 ** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
2938 ** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
2939 **
2940 ** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]]
2941 ** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
2942 ** <dd>The maximum length of the pattern argument to the [LIKE] or
2943 ** [GLOB] operators.</dd>)^
2944 **
2945 ** [[SQLITE_LIMIT_VARIABLE_NUMBER]]
2946 ** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
2947 ** <dd>The maximum index number of any [parameter] in an SQL statement.)^
2948 **
2949 ** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
2950 ** <dd>The maximum depth of recursion for triggers.</dd>)^
2951 ** </dl>
2952 */
2953 #define SQLITE_LIMIT_LENGTH 0
2954 #define SQLITE_LIMIT_SQL_LENGTH 1
2955 #define SQLITE_LIMIT_COLUMN 2
2956 #define SQLITE_LIMIT_EXPR_DEPTH 3
2957 #define SQLITE_LIMIT_COMPOUND_SELECT 4
2958 #define SQLITE_LIMIT_VDBE_OP 5
2959 #define SQLITE_LIMIT_FUNCTION_ARG 6
2960 #define SQLITE_LIMIT_ATTACHED 7
2961 #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8
2962 #define SQLITE_LIMIT_VARIABLE_NUMBER 9
2963 #define SQLITE_LIMIT_TRIGGER_DEPTH 10
2964
2965 /*
2966 ** CAPI3REF: Compiling An SQL Statement
2967 ** KEYWORDS: {SQL statement compiler}
2968 **
2969 ** To execute an SQL query, it must first be compiled into a byte-code
2970 ** program using one of these routines.
2971 **
2972 ** The first argument, "db", is a [database connection] obtained from a
2973 ** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
2974 ** [sqlite3_open16()]. The database connection must not have been closed.
2975 **
2976 ** The second argument, "zSql", is the statement to be compiled, encoded
2977 ** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2()
2978 ** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2()
2979 ** use UTF-16.
2980 **
2981 ** ^If the nByte argument is less than zero, then zSql is read up to the
2982 ** first zero terminator. ^If nByte is non-negative, then it is the maximum
2983 ** number of bytes read from zSql. ^When nByte is non-negative, the
2984 ** zSql string ends at either the first '\000' or '\u0000' character or
2985 ** the nByte-th byte, whichever comes first. If the caller knows
2986 ** that the supplied string is nul-terminated, then there is a small
2987 ** performance advantage to be gained by passing an nByte parameter that
2988 ** is equal to the number of bytes in the input string <i>including</i>
2989 ** the nul-terminator bytes as this saves SQLite from having to
2990 ** make a copy of the input string.
2991 **
2992 ** ^If pzTail is not NULL then *pzTail is made to point to the first byte
2993 ** past the end of the first SQL statement in zSql. These routines only
2994 ** compile the first statement in zSql, so *pzTail is left pointing to
2995 ** what remains uncompiled.
2996 **
2997 ** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
2998 ** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set
2999 ** to NULL. ^If the input text contains no SQL (if the input is an empty
3000 ** string or a comment) then *ppStmt is set to NULL.
3001 ** The calling procedure is responsible for deleting the compiled
3002 ** SQL statement using [sqlite3_finalize()] after it has finished with it.
3003 ** ppStmt may not be NULL.
3004 **
3005 ** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
3006 ** otherwise an [error code] is returned.
3007 **
3008 ** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are
3009 ** recommended for all new programs. The two older interfaces are retained
3010 ** for backwards compatibility, but their use is discouraged.
3011 ** ^In the "v2" interfaces, the prepared statement
3012 ** that is returned (the [sqlite3_stmt] object) contains a copy of the
3013 ** original SQL text. This causes the [sqlite3_step()] interface to
3014 ** behave differently in three ways:
3015 **
3016 ** <ol>
3017 ** <li>
3018 ** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
3019 ** always used to do, [sqlite3_step()] will automatically recompile the SQL
3020 ** statement and try to run it again.
3021 ** </li>
3022 **
3023 ** <li>
3024 ** ^When an error occurs, [sqlite3_step()] will return one of the detailed
3025 ** [error codes] or [extended error codes]. ^The legacy behavior was that
3026 ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
3027 ** and the application would have to make a second call to [sqlite3_reset()]
3028 ** in order to find the underlying cause of the problem. With the "v2" prepare
3029 ** interfaces, the underlying reason for the error is returned immediately.
3030 ** </li>
3031 **
3032 ** <li>
3033 ** ^If the specific value bound to [parameter | host parameter] in the
3034 ** WHERE clause might influence the choice of query plan for a statement,
3035 ** then the statement will be automatically recompiled, as if there had been
3036 ** a schema change, on the first [sqlite3_step()] call following any change
3037 ** to the [sqlite3_bind_text | bindings] of that [parameter].
3038 ** ^The specific value of WHERE-clause [parameter] might influence the
3039 ** choice of query plan if the parameter is the left-hand side of a [LIKE]
3040 ** or [GLOB] operator or if the parameter is compared to an indexed column
3041 ** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled.
3042 ** the
3043 ** </li>
3044 ** </ol>
3045 */
3046 SQLITE_API int sqlite3_prepare(
3047 sqlite3 *db, /* Database handle */
3048 const char *zSql, /* SQL statement, UTF-8 encoded */
3049 int nByte, /* Maximum length of zSql in bytes. */
3050 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3051 const char **pzTail /* OUT: Pointer to unused portion of zSql */
3052 );
3053 SQLITE_API int sqlite3_prepare_v2(
3054 sqlite3 *db, /* Database handle */
3055 const char *zSql, /* SQL statement, UTF-8 encoded */
3056 int nByte, /* Maximum length of zSql in bytes. */
3057 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3058 const char **pzTail /* OUT: Pointer to unused portion of zSql */
3059 );
3060 SQLITE_API int sqlite3_prepare16(
3061 sqlite3 *db, /* Database handle */
3062 const void *zSql, /* SQL statement, UTF-16 encoded */
3063 int nByte, /* Maximum length of zSql in bytes. */
3064 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3065 const void **pzTail /* OUT: Pointer to unused portion of zSql */
3066 );
3067 SQLITE_API int sqlite3_prepare16_v2(
3068 sqlite3 *db, /* Database handle */
3069 const void *zSql, /* SQL statement, UTF-16 encoded */
3070 int nByte, /* Maximum length of zSql in bytes. */
3071 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3072 const void **pzTail /* OUT: Pointer to unused portion of zSql */
3073 );
3074
3075 /*
3076 ** CAPI3REF: Retrieving Statement SQL
3077 **
3078 ** ^This interface can be used to retrieve a saved copy of the original
3079 ** SQL text used to create a [prepared statement] if that statement was
3080 ** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()].
3081 */
3082 SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt);
3083
3084 /*
3085 ** CAPI3REF: Determine If An SQL Statement Writes The Database
3086 **
3087 ** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
3088 ** and only if the [prepared statement] X makes no direct changes to
3089 ** the content of the database file.
3090 **
3091 ** Note that [application-defined SQL functions] or
3092 ** [virtual tables] might change the database indirectly as a side effect.
3093 ** ^(For example, if an application defines a function "eval()" that
3094 ** calls [sqlite3_exec()], then the following SQL statement would
3095 ** change the database file through side-effects:
3096 **
3097 ** <blockquote><pre>
3098 ** SELECT eval('DELETE FROM t1') FROM t2;
3099 ** </pre></blockquote>
3100 **
3101 ** But because the [SELECT] statement does not change the database file
3102 ** directly, sqlite3_stmt_readonly() would still return true.)^
3103 **
3104 ** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
3105 ** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
3106 ** since the statements themselves do not actually modify the database but
3107 ** rather they control the timing of when other statements modify the
3108 ** database. ^The [ATTACH] and [DETACH] statements also cause
3109 ** sqlite3_stmt_readonly() to return true since, while those statements
3110 ** change the configuration of a database connection, they do not make
3111 ** changes to the content of the database files on disk.
3112 */
3113 SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
3114
3115 /*
3116 ** CAPI3REF: Determine If A Prepared Statement Has Been Reset
3117 **
3118 ** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
3119 ** [prepared statement] S has been stepped at least once using
3120 ** [sqlite3_step(S)] but has not run to completion and/or has not
3121 ** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S)
3122 ** interface returns false if S is a NULL pointer. If S is not a
3123 ** NULL pointer and is not a pointer to a valid [prepared statement]
3124 ** object, then the behavior is undefined and probably undesirable.
3125 **
3126 ** This interface can be used in combination [sqlite3_next_stmt()]
3127 ** to locate all prepared statements associated with a database
3128 ** connection that are in need of being reset. This can be used,
3129 ** for example, in diagnostic routines to search for prepared
3130 ** statements that are holding a transaction open.
3131 */
3132 SQLITE_API int sqlite3_stmt_busy(sqlite3_stmt*);
3133
3134 /*
3135 ** CAPI3REF: Dynamically Typed Value Object
3136 ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
3137 **
3138 ** SQLite uses the sqlite3_value object to represent all values
3139 ** that can be stored in a database table. SQLite uses dynamic typing
3140 ** for the values it stores. ^Values stored in sqlite3_value objects
3141 ** can be integers, floating point values, strings, BLOBs, or NULL.
3142 **
3143 ** An sqlite3_value object may be either "protected" or "unprotected".
3144 ** Some interfaces require a protected sqlite3_value. Other interfaces
3145 ** will accept either a protected or an unprotected sqlite3_value.
3146 ** Every interface that accepts sqlite3_value arguments specifies
3147 ** whether or not it requires a protected sqlite3_value.
3148 **
3149 ** The terms "protected" and "unprotected" refer to whether or not
3150 ** a mutex is held. An internal mutex is held for a protected
3151 ** sqlite3_value object but no mutex is held for an unprotected
3152 ** sqlite3_value object. If SQLite is compiled to be single-threaded
3153 ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
3154 ** or if SQLite is run in one of reduced mutex modes
3155 ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
3156 ** then there is no distinction between protected and unprotected
3157 ** sqlite3_value objects and they can be used interchangeably. However,
3158 ** for maximum code portability it is recommended that applications
3159 ** still make the distinction between protected and unprotected
3160 ** sqlite3_value objects even when not strictly required.
3161 **
3162 ** ^The sqlite3_value objects that are passed as parameters into the
3163 ** implementation of [application-defined SQL functions] are protected.
3164 ** ^The sqlite3_value object returned by
3165 ** [sqlite3_column_value()] is unprotected.
3166 ** Unprotected sqlite3_value objects may only be used with
3167 ** [sqlite3_result_value()] and [sqlite3_bind_value()].
3168 ** The [sqlite3_value_blob | sqlite3_value_type()] family of
3169 ** interfaces require protected sqlite3_value objects.
3170 */
3171 typedef struct Mem sqlite3_value;
3172
3173 /*
3174 ** CAPI3REF: SQL Function Context Object
3175 **
3176 ** The context in which an SQL function executes is stored in an
3177 ** sqlite3_context object. ^A pointer to an sqlite3_context object
3178 ** is always first parameter to [application-defined SQL functions].
3179 ** The application-defined SQL function implementation will pass this
3180 ** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
3181 ** [sqlite3_aggregate_context()], [sqlite3_user_data()],
3182 ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
3183 ** and/or [sqlite3_set_auxdata()].
3184 */
3185 typedef struct sqlite3_context sqlite3_context;
3186
3187 /*
3188 ** CAPI3REF: Binding Values To Prepared Statements
3189 ** KEYWORDS: {host parameter} {host parameters} {host parameter name}
3190 ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
3191 **
3192 ** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
3193 ** literals may be replaced by a [parameter] that matches one of following
3194 ** templates:
3195 **
3196 ** <ul>
3197 ** <li> ?
3198 ** <li> ?NNN
3199 ** <li> :VVV
3200 ** <li> @VVV
3201 ** <li> $VVV
3202 ** </ul>
3203 **
3204 ** In the templates above, NNN represents an integer literal,
3205 ** and VVV represents an alphanumeric identifier.)^ ^The values of these
3206 ** parameters (also called "host parameter names" or "SQL parameters")
3207 ** can be set using the sqlite3_bind_*() routines defined here.
3208 **
3209 ** ^The first argument to the sqlite3_bind_*() routines is always
3210 ** a pointer to the [sqlite3_stmt] object returned from
3211 ** [sqlite3_prepare_v2()] or its variants.
3212 **
3213 ** ^The second argument is the index of the SQL parameter to be set.
3214 ** ^The leftmost SQL parameter has an index of 1. ^When the same named
3215 ** SQL parameter is used more than once, second and subsequent
3216 ** occurrences have the same index as the first occurrence.
3217 ** ^The index for named parameters can be looked up using the
3218 ** [sqlite3_bind_parameter_index()] API if desired. ^The index
3219 ** for "?NNN" parameters is the value of NNN.
3220 ** ^The NNN value must be between 1 and the [sqlite3_limit()]
3221 ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999).
3222 **
3223 ** ^The third argument is the value to bind to the parameter.
3224 **
3225 ** ^(In those routines that have a fourth argument, its value is the
3226 ** number of bytes in the parameter. To be clear: the value is the
3227 ** number of <u>bytes</u> in the value, not the number of characters.)^
3228 ** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()
3229 ** is negative, then the length of the string is
3230 ** the number of bytes up to the first zero terminator.
3231 ** If the fourth parameter to sqlite3_bind_blob() is negative, then
3232 ** the behavior is undefined.
3233 ** If a non-negative fourth parameter is provided to sqlite3_bind_text()
3234 ** or sqlite3_bind_text16() then that parameter must be the byte offset
3235 ** where the NUL terminator would occur assuming the string were NUL
3236 ** terminated. If any NUL characters occur at byte offsets less than
3237 ** the value of the fourth parameter then the resulting string value will
3238 ** contain embedded NULs. The result of expressions involving strings
3239 ** with embedded NULs is undefined.
3240 **
3241 ** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and
3242 ** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or
3243 ** string after SQLite has finished with it. ^The destructor is called
3244 ** to dispose of the BLOB or string even if the call to sqlite3_bind_blob(),
3245 ** sqlite3_bind_text(), or sqlite3_bind_text16() fails.
3246 ** ^If the fifth argument is
3247 ** the special value [SQLITE_STATIC], then SQLite assumes that the
3248 ** information is in static, unmanaged space and does not need to be freed.
3249 ** ^If the fifth argument has the value [SQLITE_TRANSIENT], then
3250 ** SQLite makes its own private copy of the data immediately, before
3251 ** the sqlite3_bind_*() routine returns.
3252 **
3253 ** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
3254 ** is filled with zeroes. ^A zeroblob uses a fixed amount of memory
3255 ** (just an integer to hold its size) while it is being processed.
3256 ** Zeroblobs are intended to serve as placeholders for BLOBs whose
3257 ** content is later written using
3258 ** [sqlite3_blob_open | incremental BLOB I/O] routines.
3259 ** ^A negative value for the zeroblob results in a zero-length BLOB.
3260 **
3261 ** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
3262 ** for the [prepared statement] or with a prepared statement for which
3263 ** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
3264 ** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_()
3265 ** routine is passed a [prepared statement] that has been finalized, the
3266 ** result is undefined and probably harmful.
3267 **
3268 ** ^Bindings are not cleared by the [sqlite3_reset()] routine.
3269 ** ^Unbound parameters are interpreted as NULL.
3270 **
3271 ** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
3272 ** [error code] if anything goes wrong.
3273 ** ^[SQLITE_RANGE] is returned if the parameter
3274 ** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails.
3275 **
3276 ** See also: [sqlite3_bind_parameter_count()],
3277 ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
3278 */
3279 SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
3280 SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double);
3281 SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int);
3282 SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
3283 SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int);
3284 SQLITE_API int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*));
3285 SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
3286 SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
3287 SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
3288
3289 /*
3290 ** CAPI3REF: Number Of SQL Parameters
3291 **
3292 ** ^This routine can be used to find the number of [SQL parameters]
3293 ** in a [prepared statement]. SQL parameters are tokens of the
3294 ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
3295 ** placeholders for values that are [sqlite3_bind_blob | bound]
3296 ** to the parameters at a later time.
3297 **
3298 ** ^(This routine actually returns the index of the largest (rightmost)
3299 ** parameter. For all forms except ?NNN, this will correspond to the
3300 ** number of unique parameters. If parameters of the ?NNN form are used,
3301 ** there may be gaps in the list.)^
3302 **
3303 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
3304 ** [sqlite3_bind_parameter_name()], and
3305 ** [sqlite3_bind_parameter_index()].
3306 */
3307 SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*);
3308
3309 /*
3310 ** CAPI3REF: Name Of A Host Parameter
3311 **
3312 ** ^The sqlite3_bind_parameter_name(P,N) interface returns
3313 ** the name of the N-th [SQL parameter] in the [prepared statement] P.
3314 ** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
3315 ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
3316 ** respectively.
3317 ** In other words, the initial ":" or "$" or "@" or "?"
3318 ** is included as part of the name.)^
3319 ** ^Parameters of the form "?" without a following integer have no name
3320 ** and are referred to as "nameless" or "anonymous parameters".
3321 **
3322 ** ^The first host parameter has an index of 1, not 0.
3323 **
3324 ** ^If the value N is out of range or if the N-th parameter is
3325 ** nameless, then NULL is returned. ^The returned string is
3326 ** always in UTF-8 encoding even if the named parameter was
3327 ** originally specified as UTF-16 in [sqlite3_prepare16()] or
3328 ** [sqlite3_prepare16_v2()].
3329 **
3330 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
3331 ** [sqlite3_bind_parameter_count()], and
3332 ** [sqlite3_bind_parameter_index()].
3333 */
3334 SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
3335
3336 /*
3337 ** CAPI3REF: Index Of A Parameter With A Given Name
3338 **
3339 ** ^Return the index of an SQL parameter given its name. ^The
3340 ** index value returned is suitable for use as the second
3341 ** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero
3342 ** is returned if no matching parameter is found. ^The parameter
3343 ** name must be given in UTF-8 even if the original statement
3344 ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()].
3345 **
3346 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
3347 ** [sqlite3_bind_parameter_count()], and
3348 ** [sqlite3_bind_parameter_index()].
3349 */
3350 SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
3351
3352 /*
3353 ** CAPI3REF: Reset All Bindings On A Prepared Statement
3354 **
3355 ** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
3356 ** the [sqlite3_bind_blob | bindings] on a [prepared statement].
3357 ** ^Use this routine to reset all host parameters to NULL.
3358 */
3359 SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*);
3360
3361 /*
3362 ** CAPI3REF: Number Of Columns In A Result Set
3363 **
3364 ** ^Return the number of columns in the result set returned by the
3365 ** [prepared statement]. ^This routine returns 0 if pStmt is an SQL
3366 ** statement that does not return data (for example an [UPDATE]).
3367 **
3368 ** See also: [sqlite3_data_count()]
3369 */
3370 SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt);
3371
3372 /*
3373 ** CAPI3REF: Column Names In A Result Set
3374 **
3375 ** ^These routines return the name assigned to a particular column
3376 ** in the result set of a [SELECT] statement. ^The sqlite3_column_name()
3377 ** interface returns a pointer to a zero-terminated UTF-8 string
3378 ** and sqlite3_column_name16() returns a pointer to a zero-terminated
3379 ** UTF-16 string. ^The first parameter is the [prepared statement]
3380 ** that implements the [SELECT] statement. ^The second parameter is the
3381 ** column number. ^The leftmost column is number 0.
3382 **
3383 ** ^The returned string pointer is valid until either the [prepared statement]
3384 ** is destroyed by [sqlite3_finalize()] or until the statement is automatically
3385 ** reprepared by the first call to [sqlite3_step()] for a particular run
3386 ** or until the next call to
3387 ** sqlite3_column_name() or sqlite3_column_name16() on the same column.
3388 **
3389 ** ^If sqlite3_malloc() fails during the processing of either routine
3390 ** (for example during a conversion from UTF-8 to UTF-16) then a
3391 ** NULL pointer is returned.
3392 **
3393 ** ^The name of a result column is the value of the "AS" clause for
3394 ** that column, if there is an AS clause. If there is no AS clause
3395 ** then the name of the column is unspecified and may change from
3396 ** one release of SQLite to the next.
3397 */
3398 SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N);
3399 SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N);
3400
3401 /*
3402 ** CAPI3REF: Source Of Data In A Query Result
3403 **
3404 ** ^These routines provide a means to determine the database, table, and
3405 ** table column that is the origin of a particular result column in
3406 ** [SELECT] statement.
3407 ** ^The name of the database or table or column can be returned as
3408 ** either a UTF-8 or UTF-16 string. ^The _database_ routines return
3409 ** the database name, the _table_ routines return the table name, and
3410 ** the origin_ routines return the column name.
3411 ** ^The returned string is valid until the [prepared statement] is destroyed
3412 ** using [sqlite3_finalize()] or until the statement is automatically
3413 ** reprepared by the first call to [sqlite3_step()] for a particular run
3414 ** or until the same information is requested
3415 ** again in a different encoding.
3416 **
3417 ** ^The names returned are the original un-aliased names of the
3418 ** database, table, and column.
3419 **
3420 ** ^The first argument to these interfaces is a [prepared statement].
3421 ** ^These functions return information about the Nth result column returned by
3422 ** the statement, where N is the second function argument.
3423 ** ^The left-most column is column 0 for these routines.
3424 **
3425 ** ^If the Nth column returned by the statement is an expression or
3426 ** subquery and is not a column value, then all of these functions return
3427 ** NULL. ^These routine might also return NULL if a memory allocation error
3428 ** occurs. ^Otherwise, they return the name of the attached database, table,
3429 ** or column that query result column was extracted from.
3430 **
3431 ** ^As with all other SQLite APIs, those whose names end with "16" return
3432 ** UTF-16 encoded strings and the other functions return UTF-8.
3433 **
3434 ** ^These APIs are only available if the library was compiled with the
3435 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
3436 **
3437 ** If two or more threads call one or more of these routines against the same
3438 ** prepared statement and column at the same time then the results are
3439 ** undefined.
3440 **
3441 ** If two or more threads call one or more
3442 ** [sqlite3_column_database_name | column metadata interfaces]
3443 ** for the same [prepared statement] and result column
3444 ** at the same time then the results are undefined.
3445 */
3446 SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int);
3447 SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
3448 SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int);
3449 SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
3450 SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
3451 SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
3452
3453 /*
3454 ** CAPI3REF: Declared Datatype Of A Query Result
3455 **
3456 ** ^(The first parameter is a [prepared statement].
3457 ** If this statement is a [SELECT] statement and the Nth column of the
3458 ** returned result set of that [SELECT] is a table column (not an
3459 ** expression or subquery) then the declared type of the table
3460 ** column is returned.)^ ^If the Nth column of the result set is an
3461 ** expression or subquery, then a NULL pointer is returned.
3462 ** ^The returned string is always UTF-8 encoded.
3463 **
3464 ** ^(For example, given the database schema:
3465 **
3466 ** CREATE TABLE t1(c1 VARIANT);
3467 **
3468 ** and the following statement to be compiled:
3469 **
3470 ** SELECT c1 + 1, c1 FROM t1;
3471 **
3472 ** this routine would return the string "VARIANT" for the second result
3473 ** column (i==1), and a NULL pointer for the first result column (i==0).)^
3474 **
3475 ** ^SQLite uses dynamic run-time typing. ^So just because a column
3476 ** is declared to contain a particular type does not mean that the
3477 ** data stored in that column is of the declared type. SQLite is
3478 ** strongly typed, but the typing is dynamic not static. ^Type
3479 ** is associated with individual values, not with the containers
3480 ** used to hold those values.
3481 */
3482 SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int);
3483 SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
3484
3485 /*
3486 ** CAPI3REF: Evaluate An SQL Statement
3487 **
3488 ** After a [prepared statement] has been prepared using either
3489 ** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy
3490 ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
3491 ** must be called one or more times to evaluate the statement.
3492 **
3493 ** The details of the behavior of the sqlite3_step() interface depend
3494 ** on whether the statement was prepared using the newer "v2" interface
3495 ** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy
3496 ** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the
3497 ** new "v2" interface is recommended for new applications but the legacy
3498 ** interface will continue to be supported.
3499 **
3500 ** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
3501 ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
3502 ** ^With the "v2" interface, any of the other [result codes] or
3503 ** [extended result codes] might be returned as well.
3504 **
3505 ** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
3506 ** database locks it needs to do its job. ^If the statement is a [COMMIT]
3507 ** or occurs outside of an explicit transaction, then you can retry the
3508 ** statement. If the statement is not a [COMMIT] and occurs within an
3509 ** explicit transaction then you should rollback the transaction before
3510 ** continuing.
3511 **
3512 ** ^[SQLITE_DONE] means that the statement has finished executing
3513 ** successfully. sqlite3_step() should not be called again on this virtual
3514 ** machine without first calling [sqlite3_reset()] to reset the virtual
3515 ** machine back to its initial state.
3516 **
3517 ** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
3518 ** is returned each time a new row of data is ready for processing by the
3519 ** caller. The values may be accessed using the [column access functions].
3520 ** sqlite3_step() is called again to retrieve the next row of data.
3521 **
3522 ** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
3523 ** violation) has occurred. sqlite3_step() should not be called again on
3524 ** the VM. More information may be found by calling [sqlite3_errmsg()].
3525 ** ^With the legacy interface, a more specific error code (for example,
3526 ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
3527 ** can be obtained by calling [sqlite3_reset()] on the
3528 ** [prepared statement]. ^In the "v2" interface,
3529 ** the more specific error code is returned directly by sqlite3_step().
3530 **
3531 ** [SQLITE_MISUSE] means that the this routine was called inappropriately.
3532 ** Perhaps it was called on a [prepared statement] that has
3533 ** already been [sqlite3_finalize | finalized] or on one that had
3534 ** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could
3535 ** be the case that the same database connection is being used by two or
3536 ** more threads at the same moment in time.
3537 **
3538 ** For all versions of SQLite up to and including 3.6.23.1, a call to
3539 ** [sqlite3_reset()] was required after sqlite3_step() returned anything
3540 ** other than [SQLITE_ROW] before any subsequent invocation of
3541 ** sqlite3_step(). Failure to reset the prepared statement using
3542 ** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
3543 ** sqlite3_step(). But after version 3.6.23.1, sqlite3_step() began
3544 ** calling [sqlite3_reset()] automatically in this circumstance rather
3545 ** than returning [SQLITE_MISUSE]. This is not considered a compatibility
3546 ** break because any application that ever receives an SQLITE_MISUSE error
3547 ** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option
3548 ** can be used to restore the legacy behavior.
3549 **
3550 ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
3551 ** API always returns a generic error code, [SQLITE_ERROR], following any
3552 ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call
3553 ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
3554 ** specific [error codes] that better describes the error.
3555 ** We admit that this is a goofy design. The problem has been fixed
3556 ** with the "v2" interface. If you prepare all of your SQL statements
3557 ** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead
3558 ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
3559 ** then the more specific [error codes] are returned directly
3560 ** by sqlite3_step(). The use of the "v2" interface is recommended.
3561 */
3562 SQLITE_API int sqlite3_step(sqlite3_stmt*);
3563
3564 /*
3565 ** CAPI3REF: Number of columns in a result set
3566 **
3567 ** ^The sqlite3_data_count(P) interface returns the number of columns in the
3568 ** current row of the result set of [prepared statement] P.
3569 ** ^If prepared statement P does not have results ready to return
3570 ** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of
3571 ** interfaces) then sqlite3_data_count(P) returns 0.
3572 ** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
3573 ** ^The sqlite3_data_count(P) routine returns 0 if the previous call to
3574 ** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P)
3575 ** will return non-zero if previous call to [sqlite3_step](P) returned
3576 ** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum]
3577 ** where it always returns zero since each step of that multi-step
3578 ** pragma returns 0 columns of data.
3579 **
3580 ** See also: [sqlite3_column_count()]
3581 */
3582 SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
3583
3584 /*
3585 ** CAPI3REF: Fundamental Datatypes
3586 ** KEYWORDS: SQLITE_TEXT
3587 **
3588 ** ^(Every value in SQLite has one of five fundamental datatypes:
3589 **
3590 ** <ul>
3591 ** <li> 64-bit signed integer
3592 ** <li> 64-bit IEEE floating point number
3593 ** <li> string
3594 ** <li> BLOB
3595 ** <li> NULL
3596 ** </ul>)^
3597 **
3598 ** These constants are codes for each of those types.
3599 **
3600 ** Note that the SQLITE_TEXT constant was also used in SQLite version 2
3601 ** for a completely different meaning. Software that links against both
3602 ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
3603 ** SQLITE_TEXT.
3604 */
3605 #define SQLITE_INTEGER 1
3606 #define SQLITE_FLOAT 2
3607 #define SQLITE_BLOB 4
3608 #define SQLITE_NULL 5
3609 #ifdef SQLITE_TEXT
3610 # undef SQLITE_TEXT
3611 #else
3612 # define SQLITE_TEXT 3
3613 #endif
3614 #define SQLITE3_TEXT 3
3615
3616 /*
3617 ** CAPI3REF: Result Values From A Query
3618 ** KEYWORDS: {column access functions}
3619 **
3620 ** These routines form the "result set" interface.
3621 **
3622 ** ^These routines return information about a single column of the current
3623 ** result row of a query. ^In every case the first argument is a pointer
3624 ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
3625 ** that was returned from [sqlite3_prepare_v2()] or one of its variants)
3626 ** and the second argument is the index of the column for which information
3627 ** should be returned. ^The leftmost column of the result set has the index 0.
3628 ** ^The number of columns in the result can be determined using
3629 ** [sqlite3_column_count()].
3630 **
3631 ** If the SQL statement does not currently point to a valid row, or if the
3632 ** column index is out of range, the result is undefined.
3633 ** These routines may only be called when the most recent call to
3634 ** [sqlite3_step()] has returned [SQLITE_ROW] and neither
3635 ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
3636 ** If any of these routines are called after [sqlite3_reset()] or
3637 ** [sqlite3_finalize()] or after [sqlite3_step()] has returned
3638 ** something other than [SQLITE_ROW], the results are undefined.
3639 ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
3640 ** are called from a different thread while any of these routines
3641 ** are pending, then the results are undefined.
3642 **
3643 ** ^The sqlite3_column_type() routine returns the
3644 ** [SQLITE_INTEGER | datatype code] for the initial data type
3645 ** of the result column. ^The returned value is one of [SQLITE_INTEGER],
3646 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value
3647 ** returned by sqlite3_column_type() is only meaningful if no type
3648 ** conversions have occurred as described below. After a type conversion,
3649 ** the value returned by sqlite3_column_type() is undefined. Future
3650 ** versions of SQLite may change the behavior of sqlite3_column_type()
3651 ** following a type conversion.
3652 **
3653 ** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
3654 ** routine returns the number of bytes in that BLOB or string.
3655 ** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
3656 ** the string to UTF-8 and then returns the number of bytes.
3657 ** ^If the result is a numeric value then sqlite3_column_bytes() uses
3658 ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
3659 ** the number of bytes in that string.
3660 ** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
3661 **
3662 ** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
3663 ** routine returns the number of bytes in that BLOB or string.
3664 ** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
3665 ** the string to UTF-16 and then returns the number of bytes.
3666 ** ^If the result is a numeric value then sqlite3_column_bytes16() uses
3667 ** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
3668 ** the number of bytes in that string.
3669 ** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
3670 **
3671 ** ^The values returned by [sqlite3_column_bytes()] and
3672 ** [sqlite3_column_bytes16()] do not include the zero terminators at the end
3673 ** of the string. ^For clarity: the values returned by
3674 ** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
3675 ** bytes in the string, not the number of characters.
3676 **
3677 ** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
3678 ** even empty strings, are always zero-terminated. ^The return
3679 ** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
3680 **
3681 ** ^The object returned by [sqlite3_column_value()] is an
3682 ** [unprotected sqlite3_value] object. An unprotected sqlite3_value object
3683 ** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()].
3684 ** If the [unprotected sqlite3_value] object returned by
3685 ** [sqlite3_column_value()] is used in any other way, including calls
3686 ** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
3687 ** or [sqlite3_value_bytes()], then the behavior is undefined.
3688 **
3689 ** These routines attempt to convert the value where appropriate. ^For
3690 ** example, if the internal representation is FLOAT and a text result
3691 ** is requested, [sqlite3_snprintf()] is used internally to perform the
3692 ** conversion automatically. ^(The following table details the conversions
3693 ** that are applied:
3694 **
3695 ** <blockquote>
3696 ** <table border="1">
3697 ** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion
3698 **
3699 ** <tr><td> NULL <td> INTEGER <td> Result is 0
3700 ** <tr><td> NULL <td> FLOAT <td> Result is 0.0
3701 ** <tr><td> NULL <td> TEXT <td> Result is NULL pointer
3702 ** <tr><td> NULL <td> BLOB <td> Result is NULL pointer
3703 ** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float
3704 ** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer
3705 ** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT
3706 ** <tr><td> FLOAT <td> INTEGER <td> Convert from float to integer
3707 ** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float
3708 ** <tr><td> FLOAT <td> BLOB <td> Same as FLOAT->TEXT
3709 ** <tr><td> TEXT <td> INTEGER <td> Use atoi()
3710 ** <tr><td> TEXT <td> FLOAT <td> Use atof()
3711 ** <tr><td> TEXT <td> BLOB <td> No change
3712 ** <tr><td> BLOB <td> INTEGER <td> Convert to TEXT then use atoi()
3713 ** <tr><td> BLOB <td> FLOAT <td> Convert to TEXT then use atof()
3714 ** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed
3715 ** </table>
3716 ** </blockquote>)^
3717 **
3718 ** The table above makes reference to standard C library functions atoi()
3719 ** and atof(). SQLite does not really use these functions. It has its
3720 ** own equivalent internal routines. The atoi() and atof() names are
3721 ** used in the table for brevity and because they are familiar to most
3722 ** C programmers.
3723 **
3724 ** Note that when type conversions occur, pointers returned by prior
3725 ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
3726 ** sqlite3_column_text16() may be invalidated.
3727 ** Type conversions and pointer invalidations might occur
3728 ** in the following cases:
3729 **
3730 ** <ul>
3731 ** <li> The initial content is a BLOB and sqlite3_column_text() or
3732 ** sqlite3_column_text16() is called. A zero-terminator might
3733 ** need to be added to the string.</li>
3734 ** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
3735 ** sqlite3_column_text16() is called. The content must be converted
3736 ** to UTF-16.</li>
3737 ** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
3738 ** sqlite3_column_text() is called. The content must be converted
3739 ** to UTF-8.</li>
3740 ** </ul>
3741 **
3742 ** ^Conversions between UTF-16be and UTF-16le are always done in place and do
3743 ** not invalidate a prior pointer, though of course the content of the buffer
3744 ** that the prior pointer references will have been modified. Other kinds
3745 ** of conversion are done in place when it is possible, but sometimes they
3746 ** are not possible and in those cases prior pointers are invalidated.
3747 **
3748 ** The safest and easiest to remember policy is to invoke these routines
3749 ** in one of the following ways:
3750 **
3751 ** <ul>
3752 ** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
3753 ** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
3754 ** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
3755 ** </ul>
3756 **
3757 ** In other words, you should call sqlite3_column_text(),
3758 ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
3759 ** into the desired format, then invoke sqlite3_column_bytes() or
3760 ** sqlite3_column_bytes16() to find the size of the result. Do not mix calls
3761 ** to sqlite3_column_text() or sqlite3_column_blob() with calls to
3762 ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
3763 ** with calls to sqlite3_column_bytes().
3764 **
3765 ** ^The pointers returned are valid until a type conversion occurs as
3766 ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
3767 ** [sqlite3_finalize()] is called. ^The memory space used to hold strings
3768 ** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned
3769 ** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
3770 ** [sqlite3_free()].
3771 **
3772 ** ^(If a memory allocation error occurs during the evaluation of any
3773 ** of these routines, a default value is returned. The default value
3774 ** is either the integer 0, the floating point number 0.0, or a NULL
3775 ** pointer. Subsequent calls to [sqlite3_errcode()] will return
3776 ** [SQLITE_NOMEM].)^
3777 */
3778 SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
3779 SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
3780 SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
3781 SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol);
3782 SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol);
3783 SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
3784 SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
3785 SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
3786 SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol);
3787 SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
3788
3789 /*
3790 ** CAPI3REF: Destroy A Prepared Statement Object
3791 **
3792 ** ^The sqlite3_finalize() function is called to delete a [prepared statement].
3793 ** ^If the most recent evaluation of the statement encountered no errors
3794 ** or if the statement is never been evaluated, then sqlite3_finalize() returns
3795 ** SQLITE_OK. ^If the most recent evaluation of statement S failed, then
3796 ** sqlite3_finalize(S) returns the appropriate [error code] or
3797 ** [extended error code].
3798 **
3799 ** ^The sqlite3_finalize(S) routine can be called at any point during
3800 ** the life cycle of [prepared statement] S:
3801 ** before statement S is ever evaluated, after
3802 ** one or more calls to [sqlite3_reset()], or after any call
3803 ** to [sqlite3_step()] regardless of whether or not the statement has
3804 ** completed execution.
3805 **
3806 ** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
3807 **
3808 ** The application must finalize every [prepared statement] in order to avoid
3809 ** resource leaks. It is a grievous error for the application to try to use
3810 ** a prepared statement after it has been finalized. Any use of a prepared
3811 ** statement after it has been finalized can result in undefined and
3812 ** undesirable behavior such as segfaults and heap corruption.
3813 */
3814 SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt);
3815
3816 /*
3817 ** CAPI3REF: Reset A Prepared Statement Object
3818 **
3819 ** The sqlite3_reset() function is called to reset a [prepared statement]
3820 ** object back to its initial state, ready to be re-executed.
3821 ** ^Any SQL statement variables that had values bound to them using
3822 ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
3823 ** Use [sqlite3_clear_bindings()] to reset the bindings.
3824 **
3825 ** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
3826 ** back to the beginning of its program.
3827 **
3828 ** ^If the most recent call to [sqlite3_step(S)] for the
3829 ** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
3830 ** or if [sqlite3_step(S)] has never before been called on S,
3831 ** then [sqlite3_reset(S)] returns [SQLITE_OK].
3832 **
3833 ** ^If the most recent call to [sqlite3_step(S)] for the
3834 ** [prepared statement] S indicated an error, then
3835 ** [sqlite3_reset(S)] returns an appropriate [error code].
3836 **
3837 ** ^The [sqlite3_reset(S)] interface does not change the values
3838 ** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
3839 */
3840 SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt);
3841
3842 /*
3843 ** CAPI3REF: Create Or Redefine SQL Functions
3844 ** KEYWORDS: {function creation routines}
3845 ** KEYWORDS: {application-defined SQL function}
3846 ** KEYWORDS: {application-defined SQL functions}
3847 **
3848 ** ^These functions (collectively known as "function creation routines")
3849 ** are used to add SQL functions or aggregates or to redefine the behavior
3850 ** of existing SQL functions or aggregates. The only differences between
3851 ** these routines are the text encoding expected for
3852 ** the second parameter (the name of the function being created)
3853 ** and the presence or absence of a destructor callback for
3854 ** the application data pointer.
3855 **
3856 ** ^The first parameter is the [database connection] to which the SQL
3857 ** function is to be added. ^If an application uses more than one database
3858 ** connection then application-defined SQL functions must be added
3859 ** to each database connection separately.
3860 **
3861 ** ^The second parameter is the name of the SQL function to be created or
3862 ** redefined. ^The length of the name is limited to 255 bytes in a UTF-8
3863 ** representation, exclusive of the zero-terminator. ^Note that the name
3864 ** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
3865 ** ^Any attempt to create a function with a longer name
3866 ** will result in [SQLITE_MISUSE] being returned.
3867 **
3868 ** ^The third parameter (nArg)
3869 ** is the number of arguments that the SQL function or
3870 ** aggregate takes. ^If this parameter is -1, then the SQL function or
3871 ** aggregate may take any number of arguments between 0 and the limit
3872 ** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third
3873 ** parameter is less than -1 or greater than 127 then the behavior is
3874 ** undefined.
3875 **
3876 ** ^The fourth parameter, eTextRep, specifies what
3877 ** [SQLITE_UTF8 | text encoding] this SQL function prefers for
3878 ** its parameters. Every SQL function implementation must be able to work
3879 ** with UTF-8, UTF-16le, or UTF-16be. But some implementations may be
3880 ** more efficient with one encoding than another. ^An application may
3881 ** invoke sqlite3_create_function() or sqlite3_create_function16() multiple
3882 ** times with the same function but with different values of eTextRep.
3883 ** ^When multiple implementations of the same function are available, SQLite
3884 ** will pick the one that involves the least amount of data conversion.
3885 ** If there is only a single implementation which does not care what text
3886 ** encoding is used, then the fourth argument should be [SQLITE_ANY].
3887 **
3888 ** ^(The fifth parameter is an arbitrary pointer. The implementation of the
3889 ** function can gain access to this pointer using [sqlite3_user_data()].)^
3890 **
3891 ** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are
3892 ** pointers to C-language functions that implement the SQL function or
3893 ** aggregate. ^A scalar SQL function requires an implementation of the xFunc
3894 ** callback only; NULL pointers must be passed as the xStep and xFinal
3895 ** parameters. ^An aggregate SQL function requires an implementation of xStep
3896 ** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
3897 ** SQL function or aggregate, pass NULL pointers for all three function
3898 ** callbacks.
3899 **
3900 ** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL,
3901 ** then it is destructor for the application data pointer.
3902 ** The destructor is invoked when the function is deleted, either by being
3903 ** overloaded or when the database connection closes.)^
3904 ** ^The destructor is also invoked if the call to
3905 ** sqlite3_create_function_v2() fails.
3906 ** ^When the destructor callback of the tenth parameter is invoked, it
3907 ** is passed a single argument which is a copy of the application data
3908 ** pointer which was the fifth parameter to sqlite3_create_function_v2().
3909 **
3910 ** ^It is permitted to register multiple implementations of the same
3911 ** functions with the same name but with either differing numbers of
3912 ** arguments or differing preferred text encodings. ^SQLite will use
3913 ** the implementation that most closely matches the way in which the
3914 ** SQL function is used. ^A function implementation with a non-negative
3915 ** nArg parameter is a better match than a function implementation with
3916 ** a negative nArg. ^A function where the preferred text encoding
3917 ** matches the database encoding is a better
3918 ** match than a function where the encoding is different.
3919 ** ^A function where the encoding difference is between UTF16le and UTF16be
3920 ** is a closer match than a function where the encoding difference is
3921 ** between UTF8 and UTF16.
3922 **
3923 ** ^Built-in functions may be overloaded by new application-defined functions.
3924 **
3925 ** ^An application-defined function is permitted to call other
3926 ** SQLite interfaces. However, such calls must not
3927 ** close the database connection nor finalize or reset the prepared
3928 ** statement in which the function is running.
3929 */
3930 SQLITE_API int sqlite3_create_function(
3931 sqlite3 *db,
3932 const char *zFunctionName,
3933 int nArg,
3934 int eTextRep,
3935 void *pApp,
3936 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
3937 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
3938 void (*xFinal)(sqlite3_context*)
3939 );
3940 SQLITE_API int sqlite3_create_function16(
3941 sqlite3 *db,
3942 const void *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_function_v2(
3951 sqlite3 *db,
3952 const char *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 void(*xDestroy)(void*)
3960 );
3961
3962 /*
3963 ** CAPI3REF: Text Encodings
3964 **
3965 ** These constant define integer codes that represent the various
3966 ** text encodings supported by SQLite.
3967 */
3968 #define SQLITE_UTF8 1
3969 #define SQLITE_UTF16LE 2
3970 #define SQLITE_UTF16BE 3
3971 #define SQLITE_UTF16 4 /* Use native byte order */
3972 #define SQLITE_ANY 5 /* sqlite3_create_function only */
3973 #define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */
3974
3975 /*
3976 ** CAPI3REF: Deprecated Functions
3977 ** DEPRECATED
3978 **
3979 ** These functions are [deprecated]. In order to maintain
3980 ** backwards compatibility with older code, these functions continue
3981 ** to be supported. However, new applications should avoid
3982 ** the use of these functions. To help encourage people to avoid
3983 ** using these functions, we are not going to tell you what they do.
3984 */
3985 #ifndef SQLITE_OMIT_DEPRECATED
3986 SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
3987 SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
3988 SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
3989 SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void);
3990 SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
3991 SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64);
3992 #endif
3993
3994 /*
3995 ** CAPI3REF: Obtaining SQL Function Parameter Values
3996 **
3997 ** The C-language implementation of SQL functions and aggregates uses
3998 ** this set of interface routines to access the parameter values on
3999 ** the function or aggregate.
4000 **
4001 ** The xFunc (for scalar functions) or xStep (for aggregates) parameters
4002 ** to [sqlite3_create_function()] and [sqlite3_create_function16()]
4003 ** define callbacks that implement the SQL functions and aggregates.
4004 ** The 3rd parameter to these callbacks is an array of pointers to
4005 ** [protected sqlite3_value] objects. There is one [sqlite3_value] object for
4006 ** each parameter to the SQL function. These routines are used to
4007 ** extract values from the [sqlite3_value] objects.
4008 **
4009 ** These routines work only with [protected sqlite3_value] objects.
4010 ** Any attempt to use these routines on an [unprotected sqlite3_value]
4011 ** object results in undefined behavior.
4012 **
4013 ** ^These routines work just like the corresponding [column access functions]
4014 ** except that these routines take a single [protected sqlite3_value] object
4015 ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
4016 **
4017 ** ^The sqlite3_value_text16() interface extracts a UTF-16 string
4018 ** in the native byte-order of the host machine. ^The
4019 ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
4020 ** extract UTF-16 strings as big-endian and little-endian respectively.
4021 **
4022 ** ^(The sqlite3_value_numeric_type() interface attempts to apply
4023 ** numeric affinity to the value. This means that an attempt is
4024 ** made to convert the value to an integer or floating point. If
4025 ** such a conversion is possible without loss of information (in other
4026 ** words, if the value is a string that looks like a number)
4027 ** then the conversion is performed. Otherwise no conversion occurs.
4028 ** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
4029 **
4030 ** Please pay particular attention to the fact that the pointer returned
4031 ** from [sqlite3_value_blob()], [sqlite3_value_text()], or
4032 ** [sqlite3_value_text16()] can be invalidated by a subsequent call to
4033 ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
4034 ** or [sqlite3_value_text16()].
4035 **
4036 ** These routines must be called from the same thread as
4037 ** the SQL function that supplied the [sqlite3_value*] parameters.
4038 */
4039 SQLITE_API const void *sqlite3_value_blob(sqlite3_value*);
4040 SQLITE_API int sqlite3_value_bytes(sqlite3_value*);
4041 SQLITE_API int sqlite3_value_bytes16(sqlite3_value*);
4042 SQLITE_API double sqlite3_value_double(sqlite3_value*);
4043 SQLITE_API int sqlite3_value_int(sqlite3_value*);
4044 SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
4045 SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*);
4046 SQLITE_API const void *sqlite3_value_text16(sqlite3_value*);
4047 SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*);
4048 SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*);
4049 SQLITE_API int sqlite3_value_type(sqlite3_value*);
4050 SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*);
4051
4052 /*
4053 ** CAPI3REF: Obtain Aggregate Function Context
4054 **
4055 ** Implementations of aggregate SQL functions use this
4056 ** routine to allocate memory for storing their state.
4057 **
4058 ** ^The first time the sqlite3_aggregate_context(C,N) routine is called
4059 ** for a particular aggregate function, SQLite
4060 ** allocates N of memory, zeroes out that memory, and returns a pointer
4061 ** to the new memory. ^On second and subsequent calls to
4062 ** sqlite3_aggregate_context() for the same aggregate function instance,
4063 ** the same buffer is returned. Sqlite3_aggregate_context() is normally
4064 ** called once for each invocation of the xStep callback and then one
4065 ** last time when the xFinal callback is invoked. ^(When no rows match
4066 ** an aggregate query, the xStep() callback of the aggregate function
4067 ** implementation is never called and xFinal() is called exactly once.
4068 ** In those cases, sqlite3_aggregate_context() might be called for the
4069 ** first time from within xFinal().)^
4070 **
4071 ** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer if N is
4072 ** less than or equal to zero or if a memory allocate error occurs.
4073 **
4074 ** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
4075 ** determined by the N parameter on first successful call. Changing the
4076 ** value of N in subsequent call to sqlite3_aggregate_context() within
4077 ** the same aggregate function instance will not resize the memory
4078 ** allocation.)^
4079 **
4080 ** ^SQLite automatically frees the memory allocated by
4081 ** sqlite3_aggregate_context() when the aggregate query concludes.
4082 **
4083 ** The first parameter must be a copy of the
4084 ** [sqlite3_context | SQL function context] that is the first parameter
4085 ** to the xStep or xFinal callback routine that implements the aggregate
4086 ** function.
4087 **
4088 ** This routine must be called from the same thread in which
4089 ** the aggregate SQL function is running.
4090 */
4091 SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
4092
4093 /*
4094 ** CAPI3REF: User Data For Functions
4095 **
4096 ** ^The sqlite3_user_data() interface returns a copy of
4097 ** the pointer that was the pUserData parameter (the 5th parameter)
4098 ** of the [sqlite3_create_function()]
4099 ** and [sqlite3_create_function16()] routines that originally
4100 ** registered the application defined function.
4101 **
4102 ** This routine must be called from the same thread in which
4103 ** the application-defined function is running.
4104 */
4105 SQLITE_API void *sqlite3_user_data(sqlite3_context*);
4106
4107 /*
4108 ** CAPI3REF: Database Connection For Functions
4109 **
4110 ** ^The sqlite3_context_db_handle() interface returns a copy of
4111 ** the pointer to the [database connection] (the 1st parameter)
4112 ** of the [sqlite3_create_function()]
4113 ** and [sqlite3_create_function16()] routines that originally
4114 ** registered the application defined function.
4115 */
4116 SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
4117
4118 /*
4119 ** CAPI3REF: Function Auxiliary Data
4120 **
4121 ** The following two functions may be used by scalar SQL functions to
4122 ** associate metadata with argument values. If the same value is passed to
4123 ** multiple invocations of the same SQL function during query execution, under
4124 ** some circumstances the associated metadata may be preserved. This may
4125 ** be used, for example, to add a regular-expression matching scalar
4126 ** function. The compiled version of the regular expression is stored as
4127 ** metadata associated with the SQL value passed as the regular expression
4128 ** pattern. The compiled regular expression can be reused on multiple
4129 ** invocations of the same function so that the original pattern string
4130 ** does not need to be recompiled on each invocation.
4131 **
4132 ** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata
4133 ** associated by the sqlite3_set_auxdata() function with the Nth argument
4134 ** value to the application-defined function. ^If no metadata has been ever
4135 ** been set for the Nth argument of the function, or if the corresponding
4136 ** function parameter has changed since the meta-data was set,
4137 ** then sqlite3_get_auxdata() returns a NULL pointer.
4138 **
4139 ** ^The sqlite3_set_auxdata() interface saves the metadata
4140 ** pointed to by its 3rd parameter as the metadata for the N-th
4141 ** argument of the application-defined function. Subsequent
4142 ** calls to sqlite3_get_auxdata() might return this data, if it has
4143 ** not been destroyed.
4144 ** ^If it is not NULL, SQLite will invoke the destructor
4145 ** function given by the 4th parameter to sqlite3_set_auxdata() on
4146 ** the metadata when the corresponding function parameter changes
4147 ** or when the SQL statement completes, whichever comes first.
4148 **
4149 ** SQLite is free to call the destructor and drop metadata on any
4150 ** parameter of any function at any time. ^The only guarantee is that
4151 ** the destructor will be called before the metadata is dropped.
4152 **
4153 ** ^(In practice, metadata is preserved between function calls for
4154 ** expressions that are constant at compile time. This includes literal
4155 ** values and [parameters].)^
4156 **
4157 ** These routines must be called from the same thread in which
4158 ** the SQL function is running.
4159 */
4160 SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N);
4161 SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
4162
4163
4164 /*
4165 ** CAPI3REF: Constants Defining Special Destructor Behavior
4166 **
4167 ** These are special values for the destructor that is passed in as the
4168 ** final argument to routines like [sqlite3_result_blob()]. ^If the destructor
4169 ** argument is SQLITE_STATIC, it means that the content pointer is constant
4170 ** and will never change. It does not need to be destroyed. ^The
4171 ** SQLITE_TRANSIENT value means that the content will likely change in
4172 ** the near future and that SQLite should make its own private copy of
4173 ** the content before returning.
4174 **
4175 ** The typedef is necessary to work around problems in certain
4176 ** C++ compilers. See ticket #2191.
4177 */
4178 typedef void (*sqlite3_destructor_type)(void*);
4179 #define SQLITE_STATIC ((sqlite3_destructor_type)0)
4180 #define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1)
4181
4182 /*
4183 ** CAPI3REF: Setting The Result Of An SQL Function
4184 **
4185 ** These routines are used by the xFunc or xFinal callbacks that
4186 ** implement SQL functions and aggregates. See
4187 ** [sqlite3_create_function()] and [sqlite3_create_function16()]
4188 ** for additional information.
4189 **
4190 ** These functions work very much like the [parameter binding] family of
4191 ** functions used to bind values to host parameters in prepared statements.
4192 ** Refer to the [SQL parameter] documentation for additional information.
4193 **
4194 ** ^The sqlite3_result_blob() interface sets the result from
4195 ** an application-defined function to be the BLOB whose content is pointed
4196 ** to by the second parameter and which is N bytes long where N is the
4197 ** third parameter.
4198 **
4199 ** ^The sqlite3_result_zeroblob() interfaces set the result of
4200 ** the application-defined function to be a BLOB containing all zero
4201 ** bytes and N bytes in size, where N is the value of the 2nd parameter.
4202 **
4203 ** ^The sqlite3_result_double() interface sets the result from
4204 ** an application-defined function to be a floating point value specified
4205 ** by its 2nd argument.
4206 **
4207 ** ^The sqlite3_result_error() and sqlite3_result_error16() functions
4208 ** cause the implemented SQL function to throw an exception.
4209 ** ^SQLite uses the string pointed to by the
4210 ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
4211 ** as the text of an error message. ^SQLite interprets the error
4212 ** message string from sqlite3_result_error() as UTF-8. ^SQLite
4213 ** interprets the string from sqlite3_result_error16() as UTF-16 in native
4214 ** byte order. ^If the third parameter to sqlite3_result_error()
4215 ** or sqlite3_result_error16() is negative then SQLite takes as the error
4216 ** message all text up through the first zero character.
4217 ** ^If the third parameter to sqlite3_result_error() or
4218 ** sqlite3_result_error16() is non-negative then SQLite takes that many
4219 ** bytes (not characters) from the 2nd parameter as the error message.
4220 ** ^The sqlite3_result_error() and sqlite3_result_error16()
4221 ** routines make a private copy of the error message text before
4222 ** they return. Hence, the calling function can deallocate or
4223 ** modify the text after they return without harm.
4224 ** ^The sqlite3_result_error_code() function changes the error code
4225 ** returned by SQLite as a result of an error in a function. ^By default,
4226 ** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error()
4227 ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
4228 **
4229 ** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an
4230 ** error indicating that a string or BLOB is too long to represent.
4231 **
4232 ** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an
4233 ** error indicating that a memory allocation failed.
4234 **
4235 ** ^The sqlite3_result_int() interface sets the return value
4236 ** of the application-defined function to be the 32-bit signed integer
4237 ** value given in the 2nd argument.
4238 ** ^The sqlite3_result_int64() interface sets the return value
4239 ** of the application-defined function to be the 64-bit signed integer
4240 ** value given in the 2nd argument.
4241 **
4242 ** ^The sqlite3_result_null() interface sets the return value
4243 ** of the application-defined function to be NULL.
4244 **
4245 ** ^The sqlite3_result_text(), sqlite3_result_text16(),
4246 ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
4247 ** set the return value of the application-defined function to be
4248 ** a text string which is represented as UTF-8, UTF-16 native byte order,
4249 ** UTF-16 little endian, or UTF-16 big endian, respectively.
4250 ** ^SQLite takes the text result from the application from
4251 ** the 2nd parameter of the sqlite3_result_text* interfaces.
4252 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
4253 ** is negative, then SQLite takes result text from the 2nd parameter
4254 ** through the first zero character.
4255 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
4256 ** is non-negative, then as many bytes (not characters) of the text
4257 ** pointed to by the 2nd parameter are taken as the application-defined
4258 ** function result. If the 3rd parameter is non-negative, then it
4259 ** must be the byte offset into the string where the NUL terminator would
4260 ** appear if the string where NUL terminated. If any NUL characters occur
4261 ** in the string at a byte offset that is less than the value of the 3rd
4262 ** parameter, then the resulting string will contain embedded NULs and the
4263 ** result of expressions operating on strings with embedded NULs is undefined.
4264 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
4265 ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
4266 ** function as the destructor on the text or BLOB result when it has
4267 ** finished using that result.
4268 ** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
4269 ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
4270 ** assumes that the text or BLOB result is in constant space and does not
4271 ** copy the content of the parameter nor call a destructor on the content
4272 ** when it has finished using that result.
4273 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
4274 ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
4275 ** then SQLite makes a copy of the result into space obtained from
4276 ** from [sqlite3_malloc()] before it returns.
4277 **
4278 ** ^The sqlite3_result_value() interface sets the result of
4279 ** the application-defined function to be a copy the
4280 ** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The
4281 ** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
4282 ** so that the [sqlite3_value] specified in the parameter may change or
4283 ** be deallocated after sqlite3_result_value() returns without harm.
4284 ** ^A [protected sqlite3_value] object may always be used where an
4285 ** [unprotected sqlite3_value] object is required, so either
4286 ** kind of [sqlite3_value] object can be used with this interface.
4287 **
4288 ** If these routines are called from within the different thread
4289 ** than the one containing the application-defined function that received
4290 ** the [sqlite3_context] pointer, the results are undefined.
4291 */
4292 SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
4293 SQLITE_API void sqlite3_result_double(sqlite3_context*, double);
4294 SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int);
4295 SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int);
4296 SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*);
4297 SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*);
4298 SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int);
4299 SQLITE_API void sqlite3_result_int(sqlite3_context*, int);
4300 SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
4301 SQLITE_API void sqlite3_result_null(sqlite3_context*);
4302 SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
4303 SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
4304 SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
4305 SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
4306 SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
4307 SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n);
4308
4309 /*
4310 ** CAPI3REF: Define New Collating Sequences
4311 **
4312 ** ^These functions add, remove, or modify a [collation] associated
4313 ** with the [database connection] specified as the first argument.
4314 **
4315 ** ^The name of the collation is a UTF-8 string
4316 ** for sqlite3_create_collation() and sqlite3_create_collation_v2()
4317 ** and a UTF-16 string in native byte order for sqlite3_create_collation16().
4318 ** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
4319 ** considered to be the same name.
4320 **
4321 ** ^(The third argument (eTextRep) must be one of the constants:
4322 ** <ul>
4323 ** <li> [SQLITE_UTF8],
4324 ** <li> [SQLITE_UTF16LE],
4325 ** <li> [SQLITE_UTF16BE],
4326 ** <li> [SQLITE_UTF16], or
4327 ** <li> [SQLITE_UTF16_ALIGNED].
4328 ** </ul>)^
4329 ** ^The eTextRep argument determines the encoding of strings passed
4330 ** to the collating function callback, xCallback.
4331 ** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
4332 ** force strings to be UTF16 with native byte order.
4333 ** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
4334 ** on an even byte address.
4335 **
4336 ** ^The fourth argument, pArg, is an application data pointer that is passed
4337 ** through as the first argument to the collating function callback.
4338 **
4339 ** ^The fifth argument, xCallback, is a pointer to the collating function.
4340 ** ^Multiple collating functions can be registered using the same name but
4341 ** with different eTextRep parameters and SQLite will use whichever
4342 ** function requires the least amount of data transformation.
4343 ** ^If the xCallback argument is NULL then the collating function is
4344 ** deleted. ^When all collating functions having the same name are deleted,
4345 ** that collation is no longer usable.
4346 **
4347 ** ^The collating function callback is invoked with a copy of the pArg
4348 ** application data pointer and with two strings in the encoding specified
4349 ** by the eTextRep argument. The collating function must return an
4350 ** integer that is negative, zero, or positive
4351 ** if the first string is less than, equal to, or greater than the second,
4352 ** respectively. A collating function must always return the same answer
4353 ** given the same inputs. If two or more collating functions are registered
4354 ** to the same collation name (using different eTextRep values) then all
4355 ** must give an equivalent answer when invoked with equivalent strings.
4356 ** The collating function must obey the following properties for all
4357 ** strings A, B, and C:
4358 **
4359 ** <ol>
4360 ** <li> If A==B then B==A.
4361 ** <li> If A==B and B==C then A==C.
4362 ** <li> If A&lt;B THEN B&gt;A.
4363 ** <li> If A&lt;B and B&lt;C then A&lt;C.
4364 ** </ol>
4365 **
4366 ** If a collating function fails any of the above constraints and that
4367 ** collating function is registered and used, then the behavior of SQLite
4368 ** is undefined.
4369 **
4370 ** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
4371 ** with the addition that the xDestroy callback is invoked on pArg when
4372 ** the collating function is deleted.
4373 ** ^Collating functions are deleted when they are overridden by later
4374 ** calls to the collation creation functions or when the
4375 ** [database connection] is closed using [sqlite3_close()].
4376 **
4377 ** ^The xDestroy callback is <u>not</u> called if the
4378 ** sqlite3_create_collation_v2() function fails. Applications that invoke
4379 ** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
4380 ** check the return code and dispose of the application data pointer
4381 ** themselves rather than expecting SQLite to deal with it for them.
4382 ** This is different from every other SQLite interface. The inconsistency
4383 ** is unfortunate but cannot be changed without breaking backwards
4384 ** compatibility.
4385 **
4386 ** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
4387 */
4388 SQLITE_API int sqlite3_create_collation(
4389 sqlite3*,
4390 const char *zName,
4391 int eTextRep,
4392 void *pArg,
4393 int(*xCompare)(void*,int,const void*,int,const void*)
4394 );
4395 SQLITE_API int sqlite3_create_collation_v2(
4396 sqlite3*,
4397 const char *zName,
4398 int eTextRep,
4399 void *pArg,
4400 int(*xCompare)(void*,int,const void*,int,const void*),
4401 void(*xDestroy)(void*)
4402 );
4403 SQLITE_API int sqlite3_create_collation16(
4404 sqlite3*,
4405 const void *zName,
4406 int eTextRep,
4407 void *pArg,
4408 int(*xCompare)(void*,int,const void*,int,const void*)
4409 );
4410
4411 /*
4412 ** CAPI3REF: Collation Needed Callbacks
4413 **
4414 ** ^To avoid having to register all collation sequences before a database
4415 ** can be used, a single callback function may be registered with the
4416 ** [database connection] to be invoked whenever an undefined collation
4417 ** sequence is required.
4418 **
4419 ** ^If the function is registered using the sqlite3_collation_needed() API,
4420 ** then it is passed the names of undefined collation sequences as strings
4421 ** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
4422 ** the names are passed as UTF-16 in machine native byte order.
4423 ** ^A call to either function replaces the existing collation-needed callback.
4424 **
4425 ** ^(When the callback is invoked, the first argument passed is a copy
4426 ** of the second argument to sqlite3_collation_needed() or
4427 ** sqlite3_collation_needed16(). The second argument is the database
4428 ** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
4429 ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
4430 ** sequence function required. The fourth parameter is the name of the
4431 ** required collation sequence.)^
4432 **
4433 ** The callback function should register the desired collation using
4434 ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
4435 ** [sqlite3_create_collation_v2()].
4436 */
4437 SQLITE_API int sqlite3_collation_needed(
4438 sqlite3*,
4439 void*,
4440 void(*)(void*,sqlite3*,int eTextRep,const char*)
4441 );
4442 SQLITE_API int sqlite3_collation_needed16(
4443 sqlite3*,
4444 void*,
4445 void(*)(void*,sqlite3*,int eTextRep,const void*)
4446 );
4447
4448 #ifdef SQLITE_HAS_CODEC
4449 /*
4450 ** Specify the key for an encrypted database. This routine should be
4451 ** called right after sqlite3_open().
4452 **
4453 ** The code to implement this API is not available in the public release
4454 ** of SQLite.
4455 */
4456 SQLITE_API int sqlite3_key(
4457 sqlite3 *db, /* Database to be rekeyed */
4458 const void *pKey, int nKey /* The key */
4459 );
4460
4461 /*
4462 ** Change the key on an open database. If the current database is not
4463 ** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the
4464 ** database is decrypted.
4465 **
4466 ** The code to implement this API is not available in the public release
4467 ** of SQLite.
4468 */
4469 SQLITE_API int sqlite3_rekey(
4470 sqlite3 *db, /* Database to be rekeyed */
4471 const void *pKey, int nKey /* The new key */
4472 );
4473
4474 /*
4475 ** Specify the activation key for a SEE database. Unless
4476 ** activated, none of the SEE routines will work.
4477 */
4478 SQLITE_API void sqlite3_activate_see(
4479 const char *zPassPhrase /* Activation phrase */
4480 );
4481 #endif
4482
4483 #ifdef SQLITE_ENABLE_CEROD
4484 /*
4485 ** Specify the activation key for a CEROD database. Unless
4486 ** activated, none of the CEROD routines will work.
4487 */
4488 SQLITE_API void sqlite3_activate_cerod(
4489 const char *zPassPhrase /* Activation phrase */
4490 );
4491 #endif
4492
4493 /*
4494 ** CAPI3REF: Suspend Execution For A Short Time
4495 **
4496 ** The sqlite3_sleep() function causes the current thread to suspend execution
4497 ** for at least a number of milliseconds specified in its parameter.
4498 **
4499 ** If the operating system does not support sleep requests with
4500 ** millisecond time resolution, then the time will be rounded up to
4501 ** the nearest second. The number of milliseconds of sleep actually
4502 ** requested from the operating system is returned.
4503 **
4504 ** ^SQLite implements this interface by calling the xSleep()
4505 ** method of the default [sqlite3_vfs] object. If the xSleep() method
4506 ** of the default VFS is not implemented correctly, or not implemented at
4507 ** all, then the behavior of sqlite3_sleep() may deviate from the description
4508 ** in the previous paragraphs.
4509 */
4510 SQLITE_API int sqlite3_sleep(int);
4511
4512 /*
4513 ** CAPI3REF: Name Of The Folder Holding Temporary Files
4514 **
4515 ** ^(If this global variable is made to point to a string which is
4516 ** the name of a folder (a.k.a. directory), then all temporary files
4517 ** created by SQLite when using a built-in [sqlite3_vfs | VFS]
4518 ** will be placed in that directory.)^ ^If this variable
4519 ** is a NULL pointer, then SQLite performs a search for an appropriate
4520 ** temporary file directory.
4521 **
4522 ** It is not safe to read or modify this variable in more than one
4523 ** thread at a time. It is not safe to read or modify this variable
4524 ** if a [database connection] is being used at the same time in a separate
4525 ** thread.
4526 ** It is intended that this variable be set once
4527 ** as part of process initialization and before any SQLite interface
4528 ** routines have been called and that this variable remain unchanged
4529 ** thereafter.
4530 **
4531 ** ^The [temp_store_directory pragma] may modify this variable and cause
4532 ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,
4533 ** the [temp_store_directory pragma] always assumes that any string
4534 ** that this variable points to is held in memory obtained from
4535 ** [sqlite3_malloc] and the pragma may attempt to free that memory
4536 ** using [sqlite3_free].
4537 ** Hence, if this variable is modified directly, either it should be
4538 ** made NULL or made to point to memory obtained from [sqlite3_malloc]
4539 ** or else the use of the [temp_store_directory pragma] should be avoided.
4540 **
4541 ** <b>Note to Windows Runtime users:</b> The temporary directory must be set
4542 ** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various
4543 ** features that require the use of temporary files may fail. Here is an
4544 ** example of how to do this using C++ with the Windows Runtime:
4545 **
4546 ** <blockquote><pre>
4547 ** LPCWSTR zPath = Windows::Storage::ApplicationData::Current->
4548 ** &nbsp; TemporaryFolder->Path->Data();
4549 ** char zPathBuf&#91;MAX_PATH + 1&#93;;
4550 ** memset(zPathBuf, 0, sizeof(zPathBuf));
4551 ** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),
4552 ** &nbsp; NULL, NULL);
4553 ** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);
4554 ** </pre></blockquote>
4555 */
4556 SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory;
4557
4558 /*
4559 ** CAPI3REF: Name Of The Folder Holding Database Files
4560 **
4561 ** ^(If this global variable is made to point to a string which is
4562 ** the name of a folder (a.k.a. directory), then all database files
4563 ** specified with a relative pathname and created or accessed by
4564 ** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed
4565 ** to be relative to that directory.)^ ^If this variable is a NULL
4566 ** pointer, then SQLite assumes that all database files specified
4567 ** with a relative pathname are relative to the current directory
4568 ** for the process. Only the windows VFS makes use of this global
4569 ** variable; it is ignored by the unix VFS.
4570 **
4571 ** Changing the value of this variable while a database connection is
4572 ** open can result in a corrupt database.
4573 **
4574 ** It is not safe to read or modify this variable in more than one
4575 ** thread at a time. It is not safe to read or modify this variable
4576 ** if a [database connection] is being used at the same time in a separate
4577 ** thread.
4578 ** It is intended that this variable be set once
4579 ** as part of process initialization and before any SQLite interface
4580 ** routines have been called and that this variable remain unchanged
4581 ** thereafter.
4582 **
4583 ** ^The [data_store_directory pragma] may modify this variable and cause
4584 ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,
4585 ** the [data_store_directory pragma] always assumes that any string
4586 ** that this variable points to is held in memory obtained from
4587 ** [sqlite3_malloc] and the pragma may attempt to free that memory
4588 ** using [sqlite3_free].
4589 ** Hence, if this variable is modified directly, either it should be
4590 ** made NULL or made to point to memory obtained from [sqlite3_malloc]
4591 ** or else the use of the [data_store_directory pragma] should be avoided.
4592 */
4593 SQLITE_API SQLITE_EXTERN char *sqlite3_data_directory;
4594
4595 /*
4596 ** CAPI3REF: Test For Auto-Commit Mode
4597 ** KEYWORDS: {autocommit mode}
4598 **
4599 ** ^The sqlite3_get_autocommit() interface returns non-zero or
4600 ** zero if the given database connection is or is not in autocommit mode,
4601 ** respectively. ^Autocommit mode is on by default.
4602 ** ^Autocommit mode is disabled by a [BEGIN] statement.
4603 ** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
4604 **
4605 ** If certain kinds of errors occur on a statement within a multi-statement
4606 ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
4607 ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
4608 ** transaction might be rolled back automatically. The only way to
4609 ** find out whether SQLite automatically rolled back the transaction after
4610 ** an error is to use this function.
4611 **
4612 ** If another thread changes the autocommit status of the database
4613 ** connection while this routine is running, then the return value
4614 ** is undefined.
4615 */
4616 SQLITE_API int sqlite3_get_autocommit(sqlite3*);
4617
4618 /*
4619 ** CAPI3REF: Find The Database Handle Of A Prepared Statement
4620 **
4621 ** ^The sqlite3_db_handle interface returns the [database connection] handle
4622 ** to which a [prepared statement] belongs. ^The [database connection]
4623 ** returned by sqlite3_db_handle is the same [database connection]
4624 ** that was the first argument
4625 ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
4626 ** create the statement in the first place.
4627 */
4628 SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
4629
4630 /*
4631 ** CAPI3REF: Return The Filename For A Database Connection
4632 **
4633 ** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename
4634 ** associated with database N of connection D. ^The main database file
4635 ** has the name "main". If there is no attached database N on the database
4636 ** connection D, or if database N is a temporary or in-memory database, then
4637 ** a NULL pointer is returned.
4638 **
4639 ** ^The filename returned by this function is the output of the
4640 ** xFullPathname method of the [VFS]. ^In other words, the filename
4641 ** will be an absolute pathname, even if the filename used
4642 ** to open the database originally was a URI or relative pathname.
4643 */
4644 SQLITE_API const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName);
4645
4646 /*
4647 ** CAPI3REF: Determine if a database is read-only
4648 **
4649 ** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N
4650 ** of connection D is read-only, 0 if it is read/write, or -1 if N is not
4651 ** the name of a database on connection D.
4652 */
4653 SQLITE_API int sqlite3_db_readonly(sqlite3 *db, const char *zDbName);
4654
4655 /*
4656 ** CAPI3REF: Find the next prepared statement
4657 **
4658 ** ^This interface returns a pointer to the next [prepared statement] after
4659 ** pStmt associated with the [database connection] pDb. ^If pStmt is NULL
4660 ** then this interface returns a pointer to the first prepared statement
4661 ** associated with the database connection pDb. ^If no prepared statement
4662 ** satisfies the conditions of this routine, it returns NULL.
4663 **
4664 ** The [database connection] pointer D in a call to
4665 ** [sqlite3_next_stmt(D,S)] must refer to an open database
4666 ** connection and in particular must not be a NULL pointer.
4667 */
4668 SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
4669
4670 /*
4671 ** CAPI3REF: Commit And Rollback Notification Callbacks
4672 **
4673 ** ^The sqlite3_commit_hook() interface registers a callback
4674 ** function to be invoked whenever a transaction is [COMMIT | committed].
4675 ** ^Any callback set by a previous call to sqlite3_commit_hook()
4676 ** for the same database connection is overridden.
4677 ** ^The sqlite3_rollback_hook() interface registers a callback
4678 ** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
4679 ** ^Any callback set by a previous call to sqlite3_rollback_hook()
4680 ** for the same database connection is overridden.
4681 ** ^The pArg argument is passed through to the callback.
4682 ** ^If the callback on a commit hook function returns non-zero,
4683 ** then the commit is converted into a rollback.
4684 **
4685 ** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
4686 ** return the P argument from the previous call of the same function
4687 ** on the same [database connection] D, or NULL for
4688 ** the first call for each function on D.
4689 **
4690 ** The commit and rollback hook callbacks are not reentrant.
4691 ** The callback implementation must not do anything that will modify
4692 ** the database connection that invoked the callback. Any actions
4693 ** to modify the database connection must be deferred until after the
4694 ** completion of the [sqlite3_step()] call that triggered the commit
4695 ** or rollback hook in the first place.
4696 ** Note that running any other SQL statements, including SELECT statements,
4697 ** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
4698 ** the database connections for the meaning of "modify" in this paragraph.
4699 **
4700 ** ^Registering a NULL function disables the callback.
4701 **
4702 ** ^When the commit hook callback routine returns zero, the [COMMIT]
4703 ** operation is allowed to continue normally. ^If the commit hook
4704 ** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
4705 ** ^The rollback hook is invoked on a rollback that results from a commit
4706 ** hook returning non-zero, just as it would be with any other rollback.
4707 **
4708 ** ^For the purposes of this API, a transaction is said to have been
4709 ** rolled back if an explicit "ROLLBACK" statement is executed, or
4710 ** an error or constraint causes an implicit rollback to occur.
4711 ** ^The rollback callback is not invoked if a transaction is
4712 ** automatically rolled back because the database connection is closed.
4713 **
4714 ** See also the [sqlite3_update_hook()] interface.
4715 */
4716 SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
4717 SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
4718
4719 /*
4720 ** CAPI3REF: Data Change Notification Callbacks
4721 **
4722 ** ^The sqlite3_update_hook() interface registers a callback function
4723 ** with the [database connection] identified by the first argument
4724 ** to be invoked whenever a row is updated, inserted or deleted.
4725 ** ^Any callback set by a previous call to this function
4726 ** for the same database connection is overridden.
4727 **
4728 ** ^The second argument is a pointer to the function to invoke when a
4729 ** row is updated, inserted or deleted.
4730 ** ^The first argument to the callback is a copy of the third argument
4731 ** to sqlite3_update_hook().
4732 ** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
4733 ** or [SQLITE_UPDATE], depending on the operation that caused the callback
4734 ** to be invoked.
4735 ** ^The third and fourth arguments to the callback contain pointers to the
4736 ** database and table name containing the affected row.
4737 ** ^The final callback parameter is the [rowid] of the row.
4738 ** ^In the case of an update, this is the [rowid] after the update takes place.
4739 **
4740 ** ^(The update hook is not invoked when internal system tables are
4741 ** modified (i.e. sqlite_master and sqlite_sequence).)^
4742 **
4743 ** ^In the current implementation, the update hook
4744 ** is not invoked when duplication rows are deleted because of an
4745 ** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook
4746 ** invoked when rows are deleted using the [truncate optimization].
4747 ** The exceptions defined in this paragraph might change in a future
4748 ** release of SQLite.
4749 **
4750 ** The update hook implementation must not do anything that will modify
4751 ** the database connection that invoked the update hook. Any actions
4752 ** to modify the database connection must be deferred until after the
4753 ** completion of the [sqlite3_step()] call that triggered the update hook.
4754 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
4755 ** database connections for the meaning of "modify" in this paragraph.
4756 **
4757 ** ^The sqlite3_update_hook(D,C,P) function
4758 ** returns the P argument from the previous call
4759 ** on the same [database connection] D, or NULL for
4760 ** the first call on D.
4761 **
4762 ** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()]
4763 ** interfaces.
4764 */
4765 SQLITE_API void *sqlite3_update_hook(
4766 sqlite3*,
4767 void(*)(void *,int ,char const *,char const *,sqlite3_int64),
4768 void*
4769 );
4770
4771 /*
4772 ** CAPI3REF: Enable Or Disable Shared Pager Cache
4773 **
4774 ** ^(This routine enables or disables the sharing of the database cache
4775 ** and schema data structures between [database connection | connections]
4776 ** to the same database. Sharing is enabled if the argument is true
4777 ** and disabled if the argument is false.)^
4778 **
4779 ** ^Cache sharing is enabled and disabled for an entire process.
4780 ** This is a change as of SQLite version 3.5.0. In prior versions of SQLite,
4781 ** sharing was enabled or disabled for each thread separately.
4782 **
4783 ** ^(The cache sharing mode set by this interface effects all subsequent
4784 ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
4785 ** Existing database connections continue use the sharing mode
4786 ** that was in effect at the time they were opened.)^
4787 **
4788 ** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
4789 ** successfully. An [error code] is returned otherwise.)^
4790 **
4791 ** ^Shared cache is disabled by default. But this might change in
4792 ** future releases of SQLite. Applications that care about shared
4793 ** cache setting should set it explicitly.
4794 **
4795 ** This interface is threadsafe on processors where writing a
4796 ** 32-bit integer is atomic.
4797 **
4798 ** See Also: [SQLite Shared-Cache Mode]
4799 */
4800 SQLITE_API int sqlite3_enable_shared_cache(int);
4801
4802 /*
4803 ** CAPI3REF: Attempt To Free Heap Memory
4804 **
4805 ** ^The sqlite3_release_memory() interface attempts to free N bytes
4806 ** of heap memory by deallocating non-essential memory allocations
4807 ** held by the database library. Memory used to cache database
4808 ** pages to improve performance is an example of non-essential memory.
4809 ** ^sqlite3_release_memory() returns the number of bytes actually freed,
4810 ** which might be more or less than the amount requested.
4811 ** ^The sqlite3_release_memory() routine is a no-op returning zero
4812 ** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
4813 **
4814 ** See also: [sqlite3_db_release_memory()]
4815 */
4816 SQLITE_API int sqlite3_release_memory(int);
4817
4818 /*
4819 ** CAPI3REF: Free Memory Used By A Database Connection
4820 **
4821 ** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap
4822 ** memory as possible from database connection D. Unlike the
4823 ** [sqlite3_release_memory()] interface, this interface is effect even
4824 ** when then [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
4825 ** omitted.
4826 **
4827 ** See also: [sqlite3_release_memory()]
4828 */
4829 SQLITE_API int sqlite3_db_release_memory(sqlite3*);
4830
4831 /*
4832 ** CAPI3REF: Impose A Limit On Heap Size
4833 **
4834 ** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
4835 ** soft limit on the amount of heap memory that may be allocated by SQLite.
4836 ** ^SQLite strives to keep heap memory utilization below the soft heap
4837 ** limit by reducing the number of pages held in the page cache
4838 ** as heap memory usages approaches the limit.
4839 ** ^The soft heap limit is "soft" because even though SQLite strives to stay
4840 ** below the limit, it will exceed the limit rather than generate
4841 ** an [SQLITE_NOMEM] error. In other words, the soft heap limit
4842 ** is advisory only.
4843 **
4844 ** ^The return value from sqlite3_soft_heap_limit64() is the size of
4845 ** the soft heap limit prior to the call, or negative in the case of an
4846 ** error. ^If the argument N is negative
4847 ** then no change is made to the soft heap limit. Hence, the current
4848 ** size of the soft heap limit can be determined by invoking
4849 ** sqlite3_soft_heap_limit64() with a negative argument.
4850 **
4851 ** ^If the argument N is zero then the soft heap limit is disabled.
4852 **
4853 ** ^(The soft heap limit is not enforced in the current implementation
4854 ** if one or more of following conditions are true:
4855 **
4856 ** <ul>
4857 ** <li> The soft heap limit is set to zero.
4858 ** <li> Memory accounting is disabled using a combination of the
4859 ** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
4860 ** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
4861 ** <li> An alternative page cache implementation is specified using
4862 ** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
4863 ** <li> The page cache allocates from its own memory pool supplied
4864 ** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
4865 ** from the heap.
4866 ** </ul>)^
4867 **
4868 ** Beginning with SQLite version 3.7.3, the soft heap limit is enforced
4869 ** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT]
4870 ** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT],
4871 ** the soft heap limit is enforced on every memory allocation. Without
4872 ** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced
4873 ** when memory is allocated by the page cache. Testing suggests that because
4874 ** the page cache is the predominate memory user in SQLite, most
4875 ** applications will achieve adequate soft heap limit enforcement without
4876 ** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT].
4877 **
4878 ** The circumstances under which SQLite will enforce the soft heap limit may
4879 ** changes in future releases of SQLite.
4880 */
4881 SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);
4882
4883 /*
4884 ** CAPI3REF: Deprecated Soft Heap Limit Interface
4885 ** DEPRECATED
4886 **
4887 ** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
4888 ** interface. This routine is provided for historical compatibility
4889 ** only. All new applications should use the
4890 ** [sqlite3_soft_heap_limit64()] interface rather than this one.
4891 */
4892 SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N);
4893
4894
4895 /*
4896 ** CAPI3REF: Extract Metadata About A Column Of A Table
4897 **
4898 ** ^This routine returns metadata about a specific column of a specific
4899 ** database table accessible using the [database connection] handle
4900 ** passed as the first function argument.
4901 **
4902 ** ^The column is identified by the second, third and fourth parameters to
4903 ** this function. ^The second parameter is either the name of the database
4904 ** (i.e. "main", "temp", or an attached database) containing the specified
4905 ** table or NULL. ^If it is NULL, then all attached databases are searched
4906 ** for the table using the same algorithm used by the database engine to
4907 ** resolve unqualified table references.
4908 **
4909 ** ^The third and fourth parameters to this function are the table and column
4910 ** name of the desired column, respectively. Neither of these parameters
4911 ** may be NULL.
4912 **
4913 ** ^Metadata is returned by writing to the memory locations passed as the 5th
4914 ** and subsequent parameters to this function. ^Any of these arguments may be
4915 ** NULL, in which case the corresponding element of metadata is omitted.
4916 **
4917 ** ^(<blockquote>
4918 ** <table border="1">
4919 ** <tr><th> Parameter <th> Output<br>Type <th> Description
4920 **
4921 ** <tr><td> 5th <td> const char* <td> Data type
4922 ** <tr><td> 6th <td> const char* <td> Name of default collation sequence
4923 ** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint
4924 ** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY
4925 ** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT]
4926 ** </table>
4927 ** </blockquote>)^
4928 **
4929 ** ^The memory pointed to by the character pointers returned for the
4930 ** declaration type and collation sequence is valid only until the next
4931 ** call to any SQLite API function.
4932 **
4933 ** ^If the specified table is actually a view, an [error code] is returned.
4934 **
4935 ** ^If the specified column is "rowid", "oid" or "_rowid_" and an
4936 ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
4937 ** parameters are set for the explicitly declared column. ^(If there is no
4938 ** explicitly declared [INTEGER PRIMARY KEY] column, then the output
4939 ** parameters are set as follows:
4940 **
4941 ** <pre>
4942 ** data type: "INTEGER"
4943 ** collation sequence: "BINARY"
4944 ** not null: 0
4945 ** primary key: 1
4946 ** auto increment: 0
4947 ** </pre>)^
4948 **
4949 ** ^(This function may load one or more schemas from database files. If an
4950 ** error occurs during this process, or if the requested table or column
4951 ** cannot be found, an [error code] is returned and an error message left
4952 ** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^
4953 **
4954 ** ^This API is only available if the library was compiled with the
4955 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined.
4956 */
4957 SQLITE_API int sqlite3_table_column_metadata(
4958 sqlite3 *db, /* Connection handle */
4959 const char *zDbName, /* Database name or NULL */
4960 const char *zTableName, /* Table name */
4961 const char *zColumnName, /* Column name */
4962 char const **pzDataType, /* OUTPUT: Declared data type */
4963 char const **pzCollSeq, /* OUTPUT: Collation sequence name */
4964 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */
4965 int *pPrimaryKey, /* OUTPUT: True if column part of PK */
4966 int *pAutoinc /* OUTPUT: True if column is auto-increment */
4967 );
4968
4969 /*
4970 ** CAPI3REF: Load An Extension
4971 **
4972 ** ^This interface loads an SQLite extension library from the named file.
4973 **
4974 ** ^The sqlite3_load_extension() interface attempts to load an
4975 ** SQLite extension library contained in the file zFile.
4976 **
4977 ** ^The entry point is zProc.
4978 ** ^zProc may be 0, in which case the name of the entry point
4979 ** defaults to "sqlite3_extension_init".
4980 ** ^The sqlite3_load_extension() interface returns
4981 ** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
4982 ** ^If an error occurs and pzErrMsg is not 0, then the
4983 ** [sqlite3_load_extension()] interface shall attempt to
4984 ** fill *pzErrMsg with error message text stored in memory
4985 ** obtained from [sqlite3_malloc()]. The calling function
4986 ** should free this memory by calling [sqlite3_free()].
4987 **
4988 ** ^Extension loading must be enabled using
4989 ** [sqlite3_enable_load_extension()] prior to calling this API,
4990 ** otherwise an error will be returned.
4991 **
4992 ** See also the [load_extension() SQL function].
4993 */
4994 SQLITE_API int sqlite3_load_extension(
4995 sqlite3 *db, /* Load the extension into this database connection */
4996 const char *zFile, /* Name of the shared library containing extension */
4997 const char *zProc, /* Entry point. Derived from zFile if 0 */
4998 char **pzErrMsg /* Put error message here if not 0 */
4999 );
5000
5001 /*
5002 ** CAPI3REF: Enable Or Disable Extension Loading
5003 **
5004 ** ^So as not to open security holes in older applications that are
5005 ** unprepared to deal with extension loading, and as a means of disabling
5006 ** extension loading while evaluating user-entered SQL, the following API
5007 ** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
5008 **
5009 ** ^Extension loading is off by default. See ticket #1863.
5010 ** ^Call the sqlite3_enable_load_extension() routine with onoff==1
5011 ** to turn extension loading on and call it with onoff==0 to turn
5012 ** it back off again.
5013 */
5014 SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
5015
5016 /*
5017 ** CAPI3REF: Automatically Load Statically Linked Extensions
5018 **
5019 ** ^This interface causes the xEntryPoint() function to be invoked for
5020 ** each new [database connection] that is created. The idea here is that
5021 ** xEntryPoint() is the entry point for a statically linked SQLite extension
5022 ** that is to be automatically loaded into all new database connections.
5023 **
5024 ** ^(Even though the function prototype shows that xEntryPoint() takes
5025 ** no arguments and returns void, SQLite invokes xEntryPoint() with three
5026 ** arguments and expects and integer result as if the signature of the
5027 ** entry point where as follows:
5028 **
5029 ** <blockquote><pre>
5030 ** &nbsp; int xEntryPoint(
5031 ** &nbsp; sqlite3 *db,
5032 ** &nbsp; const char **pzErrMsg,
5033 ** &nbsp; const struct sqlite3_api_routines *pThunk
5034 ** &nbsp; );
5035 ** </pre></blockquote>)^
5036 **
5037 ** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
5038 ** point to an appropriate error message (obtained from [sqlite3_mprintf()])
5039 ** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg
5040 ** is NULL before calling the xEntryPoint(). ^SQLite will invoke
5041 ** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any
5042 ** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
5043 ** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
5044 **
5045 ** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
5046 ** on the list of automatic extensions is a harmless no-op. ^No entry point
5047 ** will be called more than once for each database connection that is opened.
5048 **
5049 ** See also: [sqlite3_reset_auto_extension()].
5050 */
5051 SQLITE_API int sqlite3_auto_extension(void (*xEntryPoint)(void));
5052
5053 /*
5054 ** CAPI3REF: Reset Automatic Extension Loading
5055 **
5056 ** ^This interface disables all automatic extensions previously
5057 ** registered using [sqlite3_auto_extension()].
5058 */
5059 SQLITE_API void sqlite3_reset_auto_extension(void);
5060
5061 /*
5062 ** The interface to the virtual-table mechanism is currently considered
5063 ** to be experimental. The interface might change in incompatible ways.
5064 ** If this is a problem for you, do not use the interface at this time.
5065 **
5066 ** When the virtual-table mechanism stabilizes, we will declare the
5067 ** interface fixed, support it indefinitely, and remove this comment.
5068 */
5069
5070 /*
5071 ** Structures used by the virtual table interface
5072 */
5073 typedef struct sqlite3_vtab sqlite3_vtab;
5074 typedef struct sqlite3_index_info sqlite3_index_info;
5075 typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
5076 typedef struct sqlite3_module sqlite3_module;
5077
5078 /*
5079 ** CAPI3REF: Virtual Table Object
5080 ** KEYWORDS: sqlite3_module {virtual table module}
5081 **
5082 ** This structure, sometimes called a "virtual table module",
5083 ** defines the implementation of a [virtual tables].
5084 ** This structure consists mostly of methods for the module.
5085 **
5086 ** ^A virtual table module is created by filling in a persistent
5087 ** instance of this structure and passing a pointer to that instance
5088 ** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
5089 ** ^The registration remains valid until it is replaced by a different
5090 ** module or until the [database connection] closes. The content
5091 ** of this structure must not change while it is registered with
5092 ** any database connection.
5093 */
5094 struct sqlite3_module {
5095 int iVersion;
5096 int (*xCreate)(sqlite3*, void *pAux,
5097 int argc, const char *const*argv,
5098 sqlite3_vtab **ppVTab, char**);
5099 int (*xConnect)(sqlite3*, void *pAux,
5100 int argc, const char *const*argv,
5101 sqlite3_vtab **ppVTab, char**);
5102 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
5103 int (*xDisconnect)(sqlite3_vtab *pVTab);
5104 int (*xDestroy)(sqlite3_vtab *pVTab);
5105 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
5106 int (*xClose)(sqlite3_vtab_cursor*);
5107 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
5108 int argc, sqlite3_value **argv);
5109 int (*xNext)(sqlite3_vtab_cursor*);
5110 int (*xEof)(sqlite3_vtab_cursor*);
5111 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
5112 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
5113 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
5114 int (*xBegin)(sqlite3_vtab *pVTab);
5115 int (*xSync)(sqlite3_vtab *pVTab);
5116 int (*xCommit)(sqlite3_vtab *pVTab);
5117 int (*xRollback)(sqlite3_vtab *pVTab);
5118 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
5119 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
5120 void **ppArg);
5121 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
5122 /* The methods above are in version 1 of the sqlite_module object. Those
5123 ** below are for version 2 and greater. */
5124 int (*xSavepoint)(sqlite3_vtab *pVTab, int);
5125 int (*xRelease)(sqlite3_vtab *pVTab, int);
5126 int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
5127 };
5128
5129 /*
5130 ** CAPI3REF: Virtual Table Indexing Information
5131 ** KEYWORDS: sqlite3_index_info
5132 **
5133 ** The sqlite3_index_info structure and its substructures is used as part
5134 ** of the [virtual table] interface to
5135 ** pass information into and receive the reply from the [xBestIndex]
5136 ** method of a [virtual table module]. The fields under **Inputs** are the
5137 ** inputs to xBestIndex and are read-only. xBestIndex inserts its
5138 ** results into the **Outputs** fields.
5139 **
5140 ** ^(The aConstraint[] array records WHERE clause constraints of the form:
5141 **
5142 ** <blockquote>column OP expr</blockquote>
5143 **
5144 ** where OP is =, &lt;, &lt;=, &gt;, or &gt;=.)^ ^(The particular operator is
5145 ** stored in aConstraint[].op using one of the
5146 ** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
5147 ** ^(The index of the column is stored in
5148 ** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the
5149 ** expr on the right-hand side can be evaluated (and thus the constraint
5150 ** is usable) and false if it cannot.)^
5151 **
5152 ** ^The optimizer automatically inverts terms of the form "expr OP column"
5153 ** and makes other simplifications to the WHERE clause in an attempt to
5154 ** get as many WHERE clause terms into the form shown above as possible.
5155 ** ^The aConstraint[] array only reports WHERE clause terms that are
5156 ** relevant to the particular virtual table being queried.
5157 **
5158 ** ^Information about the ORDER BY clause is stored in aOrderBy[].
5159 ** ^Each term of aOrderBy records a column of the ORDER BY clause.
5160 **
5161 ** The [xBestIndex] method must fill aConstraintUsage[] with information
5162 ** about what parameters to pass to xFilter. ^If argvIndex>0 then
5163 ** the right-hand side of the corresponding aConstraint[] is evaluated
5164 ** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit
5165 ** is true, then the constraint is assumed to be fully handled by the
5166 ** virtual table and is not checked again by SQLite.)^
5167 **
5168 ** ^The idxNum and idxPtr values are recorded and passed into the
5169 ** [xFilter] method.
5170 ** ^[sqlite3_free()] is used to free idxPtr if and only if
5171 ** needToFreeIdxPtr is true.
5172 **
5173 ** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
5174 ** the correct order to satisfy the ORDER BY clause so that no separate
5175 ** sorting step is required.
5176 **
5177 ** ^The estimatedCost value is an estimate of the cost of doing the
5178 ** particular lookup. A full scan of a table with N entries should have
5179 ** a cost of N. A binary search of a table of N entries should have a
5180 ** cost of approximately log(N).
5181 */
5182 struct sqlite3_index_info {
5183 /* Inputs */
5184 int nConstraint; /* Number of entries in aConstraint */
5185 struct sqlite3_index_constraint {
5186 int iColumn; /* Column on left-hand side of constraint */
5187 unsigned char op; /* Constraint operator */
5188 unsigned char usable; /* True if this constraint is usable */
5189 int iTermOffset; /* Used internally - xBestIndex should ignore */
5190 } *aConstraint; /* Table of WHERE clause constraints */
5191 int nOrderBy; /* Number of terms in the ORDER BY clause */
5192 struct sqlite3_index_orderby {
5193 int iColumn; /* Column number */
5194 unsigned char desc; /* True for DESC. False for ASC. */
5195 } *aOrderBy; /* The ORDER BY clause */
5196 /* Outputs */
5197 struct sqlite3_index_constraint_usage {
5198 int argvIndex; /* if >0, constraint is part of argv to xFilter */
5199 unsigned char omit; /* Do not code a test for this constraint */
5200 } *aConstraintUsage;
5201 int idxNum; /* Number used to identify the index */
5202 char *idxStr; /* String, possibly obtained from sqlite3_malloc */
5203 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */
5204 int orderByConsumed; /* True if output is already ordered */
5205 double estimatedCost; /* Estimated cost of using this index */
5206 };
5207
5208 /*
5209 ** CAPI3REF: Virtual Table Constraint Operator Codes
5210 **
5211 ** These macros defined the allowed values for the
5212 ** [sqlite3_index_info].aConstraint[].op field. Each value represents
5213 ** an operator that is part of a constraint term in the wHERE clause of
5214 ** a query that uses a [virtual table].
5215 */
5216 #define SQLITE_INDEX_CONSTRAINT_EQ 2
5217 #define SQLITE_INDEX_CONSTRAINT_GT 4
5218 #define SQLITE_INDEX_CONSTRAINT_LE 8
5219 #define SQLITE_INDEX_CONSTRAINT_LT 16
5220 #define SQLITE_INDEX_CONSTRAINT_GE 32
5221 #define SQLITE_INDEX_CONSTRAINT_MATCH 64
5222
5223 /*
5224 ** CAPI3REF: Register A Virtual Table Implementation
5225 **
5226 ** ^These routines are used to register a new [virtual table module] name.
5227 ** ^Module names must be registered before
5228 ** creating a new [virtual table] using the module and before using a
5229 ** preexisting [virtual table] for the module.
5230 **
5231 ** ^The module name is registered on the [database connection] specified
5232 ** by the first parameter. ^The name of the module is given by the
5233 ** second parameter. ^The third parameter is a pointer to
5234 ** the implementation of the [virtual table module]. ^The fourth
5235 ** parameter is an arbitrary client data pointer that is passed through
5236 ** into the [xCreate] and [xConnect] methods of the virtual table module
5237 ** when a new virtual table is be being created or reinitialized.
5238 **
5239 ** ^The sqlite3_create_module_v2() interface has a fifth parameter which
5240 ** is a pointer to a destructor for the pClientData. ^SQLite will
5241 ** invoke the destructor function (if it is not NULL) when SQLite
5242 ** no longer needs the pClientData pointer. ^The destructor will also
5243 ** be invoked if the call to sqlite3_create_module_v2() fails.
5244 ** ^The sqlite3_create_module()
5245 ** interface is equivalent to sqlite3_create_module_v2() with a NULL
5246 ** destructor.
5247 */
5248 SQLITE_API int sqlite3_create_module(
5249 sqlite3 *db, /* SQLite connection to register module with */
5250 const char *zName, /* Name of the module */
5251 const sqlite3_module *p, /* Methods for the module */
5252 void *pClientData /* Client data for xCreate/xConnect */
5253 );
5254 SQLITE_API int sqlite3_create_module_v2(
5255 sqlite3 *db, /* SQLite connection to register module with */
5256 const char *zName, /* Name of the module */
5257 const sqlite3_module *p, /* Methods for the module */
5258 void *pClientData, /* Client data for xCreate/xConnect */
5259 void(*xDestroy)(void*) /* Module destructor function */
5260 );
5261
5262 /*
5263 ** CAPI3REF: Virtual Table Instance Object
5264 ** KEYWORDS: sqlite3_vtab
5265 **
5266 ** Every [virtual table module] implementation uses a subclass
5267 ** of this object to describe a particular instance
5268 ** of the [virtual table]. Each subclass will
5269 ** be tailored to the specific needs of the module implementation.
5270 ** The purpose of this superclass is to define certain fields that are
5271 ** common to all module implementations.
5272 **
5273 ** ^Virtual tables methods can set an error message by assigning a
5274 ** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should
5275 ** take care that any prior string is freed by a call to [sqlite3_free()]
5276 ** prior to assigning a new string to zErrMsg. ^After the error message
5277 ** is delivered up to the client application, the string will be automatically
5278 ** freed by sqlite3_free() and the zErrMsg field will be zeroed.
5279 */
5280 struct sqlite3_vtab {
5281 const sqlite3_module *pModule; /* The module for this virtual table */
5282 int nRef; /* NO LONGER USED */
5283 char *zErrMsg; /* Error message from sqlite3_mprintf() */
5284 /* Virtual table implementations will typically add additional fields */
5285 };
5286
5287 /*
5288 ** CAPI3REF: Virtual Table Cursor Object
5289 ** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
5290 **
5291 ** Every [virtual table module] implementation uses a subclass of the
5292 ** following structure to describe cursors that point into the
5293 ** [virtual table] and are used
5294 ** to loop through the virtual table. Cursors are created using the
5295 ** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
5296 ** by the [sqlite3_module.xClose | xClose] method. Cursors are used
5297 ** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
5298 ** of the module. Each module implementation will define
5299 ** the content of a cursor structure to suit its own needs.
5300 **
5301 ** This superclass exists in order to define fields of the cursor that
5302 ** are common to all implementations.
5303 */
5304 struct sqlite3_vtab_cursor {
5305 sqlite3_vtab *pVtab; /* Virtual table of this cursor */
5306 /* Virtual table implementations will typically add additional fields */
5307 };
5308
5309 /*
5310 ** CAPI3REF: Declare The Schema Of A Virtual Table
5311 **
5312 ** ^The [xCreate] and [xConnect] methods of a
5313 ** [virtual table module] call this interface
5314 ** to declare the format (the names and datatypes of the columns) of
5315 ** the virtual tables they implement.
5316 */
5317 SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
5318
5319 /*
5320 ** CAPI3REF: Overload A Function For A Virtual Table
5321 **
5322 ** ^(Virtual tables can provide alternative implementations of functions
5323 ** using the [xFindFunction] method of the [virtual table module].
5324 ** But global versions of those functions
5325 ** must exist in order to be overloaded.)^
5326 **
5327 ** ^(This API makes sure a global version of a function with a particular
5328 ** name and number of parameters exists. If no such function exists
5329 ** before this API is called, a new function is created.)^ ^The implementation
5330 ** of the new function always causes an exception to be thrown. So
5331 ** the new function is not good for anything by itself. Its only
5332 ** purpose is to be a placeholder function that can be overloaded
5333 ** by a [virtual table].
5334 */
5335 SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
5336
5337 /*
5338 ** The interface to the virtual-table mechanism defined above (back up
5339 ** to a comment remarkably similar to this one) is currently considered
5340 ** to be experimental. The interface might change in incompatible ways.
5341 ** If this is a problem for you, do not use the interface at this time.
5342 **
5343 ** When the virtual-table mechanism stabilizes, we will declare the
5344 ** interface fixed, support it indefinitely, and remove this comment.
5345 */
5346
5347 /*
5348 ** CAPI3REF: A Handle To An Open BLOB
5349 ** KEYWORDS: {BLOB handle} {BLOB handles}
5350 **
5351 ** An instance of this object represents an open BLOB on which
5352 ** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
5353 ** ^Objects of this type are created by [sqlite3_blob_open()]
5354 ** and destroyed by [sqlite3_blob_close()].
5355 ** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
5356 ** can be used to read or write small subsections of the BLOB.
5357 ** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
5358 */
5359 typedef struct sqlite3_blob sqlite3_blob;
5360
5361 /*
5362 ** CAPI3REF: Open A BLOB For Incremental I/O
5363 **
5364 ** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
5365 ** in row iRow, column zColumn, table zTable in database zDb;
5366 ** in other words, the same BLOB that would be selected by:
5367 **
5368 ** <pre>
5369 ** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
5370 ** </pre>)^
5371 **
5372 ** ^If the flags parameter is non-zero, then the BLOB is opened for read
5373 ** and write access. ^If it is zero, the BLOB is opened for read access.
5374 ** ^It is not possible to open a column that is part of an index or primary
5375 ** key for writing. ^If [foreign key constraints] are enabled, it is
5376 ** not possible to open a column that is part of a [child key] for writing.
5377 **
5378 ** ^Note that the database name is not the filename that contains
5379 ** the database but rather the symbolic name of the database that
5380 ** appears after the AS keyword when the database is connected using [ATTACH].
5381 ** ^For the main database file, the database name is "main".
5382 ** ^For TEMP tables, the database name is "temp".
5383 **
5384 ** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written
5385 ** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set
5386 ** to be a null pointer.)^
5387 ** ^This function sets the [database connection] error code and message
5388 ** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related
5389 ** functions. ^Note that the *ppBlob variable is always initialized in a
5390 ** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob
5391 ** regardless of the success or failure of this routine.
5392 **
5393 ** ^(If the row that a BLOB handle points to is modified by an
5394 ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
5395 ** then the BLOB handle is marked as "expired".
5396 ** This is true if any column of the row is changed, even a column
5397 ** other than the one the BLOB handle is open on.)^
5398 ** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
5399 ** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
5400 ** ^(Changes written into a BLOB prior to the BLOB expiring are not
5401 ** rolled back by the expiration of the BLOB. Such changes will eventually
5402 ** commit if the transaction continues to completion.)^
5403 **
5404 ** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
5405 ** the opened blob. ^The size of a blob may not be changed by this
5406 ** interface. Use the [UPDATE] SQL command to change the size of a
5407 ** blob.
5408 **
5409 ** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
5410 ** and the built-in [zeroblob] SQL function can be used, if desired,
5411 ** to create an empty, zero-filled blob in which to read or write using
5412 ** this interface.
5413 **
5414 ** To avoid a resource leak, every open [BLOB handle] should eventually
5415 ** be released by a call to [sqlite3_blob_close()].
5416 */
5417 SQLITE_API int sqlite3_blob_open(
5418 sqlite3*,
5419 const char *zDb,
5420 const char *zTable,
5421 const char *zColumn,
5422 sqlite3_int64 iRow,
5423 int flags,
5424 sqlite3_blob **ppBlob
5425 );
5426
5427 /*
5428 ** CAPI3REF: Move a BLOB Handle to a New Row
5429 **
5430 ** ^This function is used to move an existing blob handle so that it points
5431 ** to a different row of the same database table. ^The new row is identified
5432 ** by the rowid value passed as the second argument. Only the row can be
5433 ** changed. ^The database, table and column on which the blob handle is open
5434 ** remain the same. Moving an existing blob handle to a new row can be
5435 ** faster than closing the existing handle and opening a new one.
5436 **
5437 ** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
5438 ** it must exist and there must be either a blob or text value stored in
5439 ** the nominated column.)^ ^If the new row is not present in the table, or if
5440 ** it does not contain a blob or text value, or if another error occurs, an
5441 ** SQLite error code is returned and the blob handle is considered aborted.
5442 ** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
5443 ** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
5444 ** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
5445 ** always returns zero.
5446 **
5447 ** ^This function sets the database handle error code and message.
5448 */
5449 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
5450
5451 /*
5452 ** CAPI3REF: Close A BLOB Handle
5453 **
5454 ** ^Closes an open [BLOB handle].
5455 **
5456 ** ^Closing a BLOB shall cause the current transaction to commit
5457 ** if there are no other BLOBs, no pending prepared statements, and the
5458 ** database connection is in [autocommit mode].
5459 ** ^If any writes were made to the BLOB, they might be held in cache
5460 ** until the close operation if they will fit.
5461 **
5462 ** ^(Closing the BLOB often forces the changes
5463 ** out to disk and so if any I/O errors occur, they will likely occur
5464 ** at the time when the BLOB is closed. Any errors that occur during
5465 ** closing are reported as a non-zero return value.)^
5466 **
5467 ** ^(The BLOB is closed unconditionally. Even if this routine returns
5468 ** an error code, the BLOB is still closed.)^
5469 **
5470 ** ^Calling this routine with a null pointer (such as would be returned
5471 ** by a failed call to [sqlite3_blob_open()]) is a harmless no-op.
5472 */
5473 SQLITE_API int sqlite3_blob_close(sqlite3_blob *);
5474
5475 /*
5476 ** CAPI3REF: Return The Size Of An Open BLOB
5477 **
5478 ** ^Returns the size in bytes of the BLOB accessible via the
5479 ** successfully opened [BLOB handle] in its only argument. ^The
5480 ** incremental blob I/O routines can only read or overwriting existing
5481 ** blob content; they cannot change the size of a blob.
5482 **
5483 ** This routine only works on a [BLOB handle] which has been created
5484 ** by a prior successful call to [sqlite3_blob_open()] and which has not
5485 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
5486 ** to this routine results in undefined and probably undesirable behavior.
5487 */
5488 SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *);
5489
5490 /*
5491 ** CAPI3REF: Read Data From A BLOB Incrementally
5492 **
5493 ** ^(This function is used to read data from an open [BLOB handle] into a
5494 ** caller-supplied buffer. N bytes of data are copied into buffer Z
5495 ** from the open BLOB, starting at offset iOffset.)^
5496 **
5497 ** ^If offset iOffset is less than N bytes from the end of the BLOB,
5498 ** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is
5499 ** less than zero, [SQLITE_ERROR] is returned and no data is read.
5500 ** ^The size of the blob (and hence the maximum value of N+iOffset)
5501 ** can be determined using the [sqlite3_blob_bytes()] interface.
5502 **
5503 ** ^An attempt to read from an expired [BLOB handle] fails with an
5504 ** error code of [SQLITE_ABORT].
5505 **
5506 ** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
5507 ** Otherwise, an [error code] or an [extended error code] is returned.)^
5508 **
5509 ** This routine only works on a [BLOB handle] which has been created
5510 ** by a prior successful call to [sqlite3_blob_open()] and which has not
5511 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
5512 ** to this routine results in undefined and probably undesirable behavior.
5513 **
5514 ** See also: [sqlite3_blob_write()].
5515 */
5516 SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
5517
5518 /*
5519 ** CAPI3REF: Write Data Into A BLOB Incrementally
5520 **
5521 ** ^This function is used to write data into an open [BLOB handle] from a
5522 ** caller-supplied buffer. ^N bytes of data are copied from the buffer Z
5523 ** into the open BLOB, starting at offset iOffset.
5524 **
5525 ** ^If the [BLOB handle] passed as the first argument was not opened for
5526 ** writing (the flags parameter to [sqlite3_blob_open()] was zero),
5527 ** this function returns [SQLITE_READONLY].
5528 **
5529 ** ^This function may only modify the contents of the BLOB; it is
5530 ** not possible to increase the size of a BLOB using this API.
5531 ** ^If offset iOffset is less than N bytes from the end of the BLOB,
5532 ** [SQLITE_ERROR] is returned and no data is written. ^If N is
5533 ** less than zero [SQLITE_ERROR] is returned and no data is written.
5534 ** The size of the BLOB (and hence the maximum value of N+iOffset)
5535 ** can be determined using the [sqlite3_blob_bytes()] interface.
5536 **
5537 ** ^An attempt to write to an expired [BLOB handle] fails with an
5538 ** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred
5539 ** before the [BLOB handle] expired are not rolled back by the
5540 ** expiration of the handle, though of course those changes might
5541 ** have been overwritten by the statement that expired the BLOB handle
5542 ** or by other independent statements.
5543 **
5544 ** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
5545 ** Otherwise, an [error code] or an [extended error code] is returned.)^
5546 **
5547 ** This routine only works on a [BLOB handle] which has been created
5548 ** by a prior successful call to [sqlite3_blob_open()] and which has not
5549 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
5550 ** to this routine results in undefined and probably undesirable behavior.
5551 **
5552 ** See also: [sqlite3_blob_read()].
5553 */
5554 SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
5555
5556 /*
5557 ** CAPI3REF: Virtual File System Objects
5558 **
5559 ** A virtual filesystem (VFS) is an [sqlite3_vfs] object
5560 ** that SQLite uses to interact
5561 ** with the underlying operating system. Most SQLite builds come with a
5562 ** single default VFS that is appropriate for the host computer.
5563 ** New VFSes can be registered and existing VFSes can be unregistered.
5564 ** The following interfaces are provided.
5565 **
5566 ** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
5567 ** ^Names are case sensitive.
5568 ** ^Names are zero-terminated UTF-8 strings.
5569 ** ^If there is no match, a NULL pointer is returned.
5570 ** ^If zVfsName is NULL then the default VFS is returned.
5571 **
5572 ** ^New VFSes are registered with sqlite3_vfs_register().
5573 ** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
5574 ** ^The same VFS can be registered multiple times without injury.
5575 ** ^To make an existing VFS into the default VFS, register it again
5576 ** with the makeDflt flag set. If two different VFSes with the
5577 ** same name are registered, the behavior is undefined. If a
5578 ** VFS is registered with a name that is NULL or an empty string,
5579 ** then the behavior is undefined.
5580 **
5581 ** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
5582 ** ^(If the default VFS is unregistered, another VFS is chosen as
5583 ** the default. The choice for the new VFS is arbitrary.)^
5584 */
5585 SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
5586 SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
5587 SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*);
5588
5589 /*
5590 ** CAPI3REF: Mutexes
5591 **
5592 ** The SQLite core uses these routines for thread
5593 ** synchronization. Though they are intended for internal
5594 ** use by SQLite, code that links against SQLite is
5595 ** permitted to use any of these routines.
5596 **
5597 ** The SQLite source code contains multiple implementations
5598 ** of these mutex routines. An appropriate implementation
5599 ** is selected automatically at compile-time. ^(The following
5600 ** implementations are available in the SQLite core:
5601 **
5602 ** <ul>
5603 ** <li> SQLITE_MUTEX_PTHREADS
5604 ** <li> SQLITE_MUTEX_W32
5605 ** <li> SQLITE_MUTEX_NOOP
5606 ** </ul>)^
5607 **
5608 ** ^The SQLITE_MUTEX_NOOP implementation is a set of routines
5609 ** that does no real locking and is appropriate for use in
5610 ** a single-threaded application. ^The SQLITE_MUTEX_PTHREADS and
5611 ** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
5612 ** and Windows.
5613 **
5614 ** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
5615 ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
5616 ** implementation is included with the library. In this case the
5617 ** application must supply a custom mutex implementation using the
5618 ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
5619 ** before calling sqlite3_initialize() or any other public sqlite3_
5620 ** function that calls sqlite3_initialize().)^
5621 **
5622 ** ^The sqlite3_mutex_alloc() routine allocates a new
5623 ** mutex and returns a pointer to it. ^If it returns NULL
5624 ** that means that a mutex could not be allocated. ^SQLite
5625 ** will unwind its stack and return an error. ^(The argument
5626 ** to sqlite3_mutex_alloc() is one of these integer constants:
5627 **
5628 ** <ul>
5629 ** <li> SQLITE_MUTEX_FAST
5630 ** <li> SQLITE_MUTEX_RECURSIVE
5631 ** <li> SQLITE_MUTEX_STATIC_MASTER
5632 ** <li> SQLITE_MUTEX_STATIC_MEM
5633 ** <li> SQLITE_MUTEX_STATIC_MEM2
5634 ** <li> SQLITE_MUTEX_STATIC_PRNG
5635 ** <li> SQLITE_MUTEX_STATIC_LRU
5636 ** <li> SQLITE_MUTEX_STATIC_LRU2
5637 ** </ul>)^
5638 **
5639 ** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
5640 ** cause sqlite3_mutex_alloc() to create
5641 ** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
5642 ** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
5643 ** The mutex implementation does not need to make a distinction
5644 ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
5645 ** not want to. ^SQLite will only request a recursive mutex in
5646 ** cases where it really needs one. ^If a faster non-recursive mutex
5647 ** implementation is available on the host platform, the mutex subsystem
5648 ** might return such a mutex in response to SQLITE_MUTEX_FAST.
5649 **
5650 ** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
5651 ** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
5652 ** a pointer to a static preexisting mutex. ^Six static mutexes are
5653 ** used by the current version of SQLite. Future versions of SQLite
5654 ** may add additional static mutexes. Static mutexes are for internal
5655 ** use by SQLite only. Applications that use SQLite mutexes should
5656 ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
5657 ** SQLITE_MUTEX_RECURSIVE.
5658 **
5659 ** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
5660 ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
5661 ** returns a different mutex on every call. ^But for the static
5662 ** mutex types, the same mutex is returned on every call that has
5663 ** the same type number.
5664 **
5665 ** ^The sqlite3_mutex_free() routine deallocates a previously
5666 ** allocated dynamic mutex. ^SQLite is careful to deallocate every
5667 ** dynamic mutex that it allocates. The dynamic mutexes must not be in
5668 ** use when they are deallocated. Attempting to deallocate a static
5669 ** mutex results in undefined behavior. ^SQLite never deallocates
5670 ** a static mutex.
5671 **
5672 ** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
5673 ** to enter a mutex. ^If another thread is already within the mutex,
5674 ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
5675 ** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
5676 ** upon successful entry. ^(Mutexes created using
5677 ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
5678 ** In such cases the,
5679 ** mutex must be exited an equal number of times before another thread
5680 ** can enter.)^ ^(If the same thread tries to enter any other
5681 ** kind of mutex more than once, the behavior is undefined.
5682 ** SQLite will never exhibit
5683 ** such behavior in its own use of mutexes.)^
5684 **
5685 ** ^(Some systems (for example, Windows 95) do not support the operation
5686 ** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try()
5687 ** will always return SQLITE_BUSY. The SQLite core only ever uses
5688 ** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^
5689 **
5690 ** ^The sqlite3_mutex_leave() routine exits a mutex that was
5691 ** previously entered by the same thread. ^(The behavior
5692 ** is undefined if the mutex is not currently entered by the
5693 ** calling thread or is not currently allocated. SQLite will
5694 ** never do either.)^
5695 **
5696 ** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
5697 ** sqlite3_mutex_leave() is a NULL pointer, then all three routines
5698 ** behave as no-ops.
5699 **
5700 ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
5701 */
5702 SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int);
5703 SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*);
5704 SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*);
5705 SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*);
5706 SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*);
5707
5708 /*
5709 ** CAPI3REF: Mutex Methods Object
5710 **
5711 ** An instance of this structure defines the low-level routines
5712 ** used to allocate and use mutexes.
5713 **
5714 ** Usually, the default mutex implementations provided by SQLite are
5715 ** sufficient, however the user has the option of substituting a custom
5716 ** implementation for specialized deployments or systems for which SQLite
5717 ** does not provide a suitable implementation. In this case, the user
5718 ** creates and populates an instance of this structure to pass
5719 ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
5720 ** Additionally, an instance of this structure can be used as an
5721 ** output variable when querying the system for the current mutex
5722 ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
5723 **
5724 ** ^The xMutexInit method defined by this structure is invoked as
5725 ** part of system initialization by the sqlite3_initialize() function.
5726 ** ^The xMutexInit routine is called by SQLite exactly once for each
5727 ** effective call to [sqlite3_initialize()].
5728 **
5729 ** ^The xMutexEnd method defined by this structure is invoked as
5730 ** part of system shutdown by the sqlite3_shutdown() function. The
5731 ** implementation of this method is expected to release all outstanding
5732 ** resources obtained by the mutex methods implementation, especially
5733 ** those obtained by the xMutexInit method. ^The xMutexEnd()
5734 ** interface is invoked exactly once for each call to [sqlite3_shutdown()].
5735 **
5736 ** ^(The remaining seven methods defined by this structure (xMutexAlloc,
5737 ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
5738 ** xMutexNotheld) implement the following interfaces (respectively):
5739 **
5740 ** <ul>
5741 ** <li> [sqlite3_mutex_alloc()] </li>
5742 ** <li> [sqlite3_mutex_free()] </li>
5743 ** <li> [sqlite3_mutex_enter()] </li>
5744 ** <li> [sqlite3_mutex_try()] </li>
5745 ** <li> [sqlite3_mutex_leave()] </li>
5746 ** <li> [sqlite3_mutex_held()] </li>
5747 ** <li> [sqlite3_mutex_notheld()] </li>
5748 ** </ul>)^
5749 **
5750 ** The only difference is that the public sqlite3_XXX functions enumerated
5751 ** above silently ignore any invocations that pass a NULL pointer instead
5752 ** of a valid mutex handle. The implementations of the methods defined
5753 ** by this structure are not required to handle this case, the results
5754 ** of passing a NULL pointer instead of a valid mutex handle are undefined
5755 ** (i.e. it is acceptable to provide an implementation that segfaults if
5756 ** it is passed a NULL pointer).
5757 **
5758 ** The xMutexInit() method must be threadsafe. ^It must be harmless to
5759 ** invoke xMutexInit() multiple times within the same process and without
5760 ** intervening calls to xMutexEnd(). Second and subsequent calls to
5761 ** xMutexInit() must be no-ops.
5762 **
5763 ** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
5764 ** and its associates). ^Similarly, xMutexAlloc() must not use SQLite memory
5765 ** allocation for a static mutex. ^However xMutexAlloc() may use SQLite
5766 ** memory allocation for a fast or recursive mutex.
5767 **
5768 ** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
5769 ** called, but only if the prior call to xMutexInit returned SQLITE_OK.
5770 ** If xMutexInit fails in any way, it is expected to clean up after itself
5771 ** prior to returning.
5772 */
5773 typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
5774 struct sqlite3_mutex_methods {
5775 int (*xMutexInit)(void);
5776 int (*xMutexEnd)(void);
5777 sqlite3_mutex *(*xMutexAlloc)(int);
5778 void (*xMutexFree)(sqlite3_mutex *);
5779 void (*xMutexEnter)(sqlite3_mutex *);
5780 int (*xMutexTry)(sqlite3_mutex *);
5781 void (*xMutexLeave)(sqlite3_mutex *);
5782 int (*xMutexHeld)(sqlite3_mutex *);
5783 int (*xMutexNotheld)(sqlite3_mutex *);
5784 };
5785
5786 /*
5787 ** CAPI3REF: Mutex Verification Routines
5788 **
5789 ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
5790 ** are intended for use inside assert() statements. ^The SQLite core
5791 ** never uses these routines except inside an assert() and applications
5792 ** are advised to follow the lead of the core. ^The SQLite core only
5793 ** provides implementations for these routines when it is compiled
5794 ** with the SQLITE_DEBUG flag. ^External mutex implementations
5795 ** are only required to provide these routines if SQLITE_DEBUG is
5796 ** defined and if NDEBUG is not defined.
5797 **
5798 ** ^These routines should return true if the mutex in their argument
5799 ** is held or not held, respectively, by the calling thread.
5800 **
5801 ** ^The implementation is not required to provide versions of these
5802 ** routines that actually work. If the implementation does not provide working
5803 ** versions of these routines, it should at least provide stubs that always
5804 ** return true so that one does not get spurious assertion failures.
5805 **
5806 ** ^If the argument to sqlite3_mutex_held() is a NULL pointer then
5807 ** the routine should return 1. This seems counter-intuitive since
5808 ** clearly the mutex cannot be held if it does not exist. But
5809 ** the reason the mutex does not exist is because the build is not
5810 ** using mutexes. And we do not want the assert() containing the
5811 ** call to sqlite3_mutex_held() to fail, so a non-zero return is
5812 ** the appropriate thing to do. ^The sqlite3_mutex_notheld()
5813 ** interface should also return 1 when given a NULL pointer.
5814 */
5815 #ifndef NDEBUG
5816 SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*);
5817 SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*);
5818 #endif
5819
5820 /*
5821 ** CAPI3REF: Mutex Types
5822 **
5823 ** The [sqlite3_mutex_alloc()] interface takes a single argument
5824 ** which is one of these integer constants.
5825 **
5826 ** The set of static mutexes may change from one SQLite release to the
5827 ** next. Applications that override the built-in mutex logic must be
5828 ** prepared to accommodate additional static mutexes.
5829 */
5830 #define SQLITE_MUTEX_FAST 0
5831 #define SQLITE_MUTEX_RECURSIVE 1
5832 #define SQLITE_MUTEX_STATIC_MASTER 2
5833 #define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */
5834 #define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */
5835 #define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */
5836 #define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */
5837 #define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */
5838 #define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */
5839 #define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */
5840
5841 /*
5842 ** CAPI3REF: Retrieve the mutex for a database connection
5843 **
5844 ** ^This interface returns a pointer the [sqlite3_mutex] object that
5845 ** serializes access to the [database connection] given in the argument
5846 ** when the [threading mode] is Serialized.
5847 ** ^If the [threading mode] is Single-thread or Multi-thread then this
5848 ** routine returns a NULL pointer.
5849 */
5850 SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
5851
5852 /*
5853 ** CAPI3REF: Low-Level Control Of Database Files
5854 **
5855 ** ^The [sqlite3_file_control()] interface makes a direct call to the
5856 ** xFileControl method for the [sqlite3_io_methods] object associated
5857 ** with a particular database identified by the second argument. ^The
5858 ** name of the database is "main" for the main database or "temp" for the
5859 ** TEMP database, or the name that appears after the AS keyword for
5860 ** databases that are added using the [ATTACH] SQL command.
5861 ** ^A NULL pointer can be used in place of "main" to refer to the
5862 ** main database file.
5863 ** ^The third and fourth parameters to this routine
5864 ** are passed directly through to the second and third parameters of
5865 ** the xFileControl method. ^The return value of the xFileControl
5866 ** method becomes the return value of this routine.
5867 **
5868 ** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes
5869 ** a pointer to the underlying [sqlite3_file] object to be written into
5870 ** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER
5871 ** case is a short-circuit path which does not actually invoke the
5872 ** underlying sqlite3_io_methods.xFileControl method.
5873 **
5874 ** ^If the second parameter (zDbName) does not match the name of any
5875 ** open database file, then SQLITE_ERROR is returned. ^This error
5876 ** code is not remembered and will not be recalled by [sqlite3_errcode()]
5877 ** or [sqlite3_errmsg()]. The underlying xFileControl method might
5878 ** also return SQLITE_ERROR. There is no way to distinguish between
5879 ** an incorrect zDbName and an SQLITE_ERROR return from the underlying
5880 ** xFileControl method.
5881 **
5882 ** See also: [SQLITE_FCNTL_LOCKSTATE]
5883 */
5884 SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
5885
5886 /*
5887 ** CAPI3REF: Testing Interface
5888 **
5889 ** ^The sqlite3_test_control() interface is used to read out internal
5890 ** state of SQLite and to inject faults into SQLite for testing
5891 ** purposes. ^The first parameter is an operation code that determines
5892 ** the number, meaning, and operation of all subsequent parameters.
5893 **
5894 ** This interface is not for use by applications. It exists solely
5895 ** for verifying the correct operation of the SQLite library. Depending
5896 ** on how the SQLite library is compiled, this interface might not exist.
5897 **
5898 ** The details of the operation codes, their meanings, the parameters
5899 ** they take, and what they do are all subject to change without notice.
5900 ** Unlike most of the SQLite API, this function is not guaranteed to
5901 ** operate consistently from one release to the next.
5902 */
5903 SQLITE_API int sqlite3_test_control(int op, ...);
5904
5905 /*
5906 ** CAPI3REF: Testing Interface Operation Codes
5907 **
5908 ** These constants are the valid operation code parameters used
5909 ** as the first argument to [sqlite3_test_control()].
5910 **
5911 ** These parameters and their meanings are subject to change
5912 ** without notice. These values are for testing purposes only.
5913 ** Applications should not use any of these parameters or the
5914 ** [sqlite3_test_control()] interface.
5915 */
5916 #define SQLITE_TESTCTRL_FIRST 5
5917 #define SQLITE_TESTCTRL_PRNG_SAVE 5
5918 #define SQLITE_TESTCTRL_PRNG_RESTORE 6
5919 #define SQLITE_TESTCTRL_PRNG_RESET 7
5920 #define SQLITE_TESTCTRL_BITVEC_TEST 8
5921 #define SQLITE_TESTCTRL_FAULT_INSTALL 9
5922 #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10
5923 #define SQLITE_TESTCTRL_PENDING_BYTE 11
5924 #define SQLITE_TESTCTRL_ASSERT 12
5925 #define SQLITE_TESTCTRL_ALWAYS 13
5926 #define SQLITE_TESTCTRL_RESERVE 14
5927 #define SQLITE_TESTCTRL_OPTIMIZATIONS 15
5928 #define SQLITE_TESTCTRL_ISKEYWORD 16
5929 #define SQLITE_TESTCTRL_SCRATCHMALLOC 17
5930 #define SQLITE_TESTCTRL_LOCALTIME_FAULT 18
5931 #define SQLITE_TESTCTRL_EXPLAIN_STMT 19
5932 #define SQLITE_TESTCTRL_LAST 19
5933
5934 /*
5935 ** CAPI3REF: SQLite Runtime Status
5936 **
5937 ** ^This interface is used to retrieve runtime status information
5938 ** about the performance of SQLite, and optionally to reset various
5939 ** highwater marks. ^The first argument is an integer code for
5940 ** the specific parameter to measure. ^(Recognized integer codes
5941 ** are of the form [status parameters | SQLITE_STATUS_...].)^
5942 ** ^The current value of the parameter is returned into *pCurrent.
5943 ** ^The highest recorded value is returned in *pHighwater. ^If the
5944 ** resetFlag is true, then the highest record value is reset after
5945 ** *pHighwater is written. ^(Some parameters do not record the highest
5946 ** value. For those parameters
5947 ** nothing is written into *pHighwater and the resetFlag is ignored.)^
5948 ** ^(Other parameters record only the highwater mark and not the current
5949 ** value. For these latter parameters nothing is written into *pCurrent.)^
5950 **
5951 ** ^The sqlite3_status() routine returns SQLITE_OK on success and a
5952 ** non-zero [error code] on failure.
5953 **
5954 ** This routine is threadsafe but is not atomic. This routine can be
5955 ** called while other threads are running the same or different SQLite
5956 ** interfaces. However the values returned in *pCurrent and
5957 ** *pHighwater reflect the status of SQLite at different points in time
5958 ** and it is possible that another thread might change the parameter
5959 ** in between the times when *pCurrent and *pHighwater are written.
5960 **
5961 ** See also: [sqlite3_db_status()]
5962 */
5963 SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
5964
5965
5966 /*
5967 ** CAPI3REF: Status Parameters
5968 ** KEYWORDS: {status parameters}
5969 **
5970 ** These integer constants designate various run-time status parameters
5971 ** that can be returned by [sqlite3_status()].
5972 **
5973 ** <dl>
5974 ** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
5975 ** <dd>This parameter is the current amount of memory checked out
5976 ** using [sqlite3_malloc()], either directly or indirectly. The
5977 ** figure includes calls made to [sqlite3_malloc()] by the application
5978 ** and internal memory usage by the SQLite library. Scratch memory
5979 ** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache
5980 ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
5981 ** this parameter. The amount returned is the sum of the allocation
5982 ** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
5983 **
5984 ** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
5985 ** <dd>This parameter records the largest memory allocation request
5986 ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
5987 ** internal equivalents). Only the value returned in the
5988 ** *pHighwater parameter to [sqlite3_status()] is of interest.
5989 ** The value written into the *pCurrent parameter is undefined.</dd>)^
5990 **
5991 ** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
5992 ** <dd>This parameter records the number of separate memory allocations
5993 ** currently checked out.</dd>)^
5994 **
5995 ** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
5996 ** <dd>This parameter returns the number of pages used out of the
5997 ** [pagecache memory allocator] that was configured using
5998 ** [SQLITE_CONFIG_PAGECACHE]. The
5999 ** value returned is in pages, not in bytes.</dd>)^
6000 **
6001 ** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]]
6002 ** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
6003 ** <dd>This parameter returns the number of bytes of page cache
6004 ** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
6005 ** buffer and where forced to overflow to [sqlite3_malloc()]. The
6006 ** returned value includes allocations that overflowed because they
6007 ** where too large (they were larger than the "sz" parameter to
6008 ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
6009 ** no space was left in the page cache.</dd>)^
6010 **
6011 ** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
6012 ** <dd>This parameter records the largest memory allocation request
6013 ** handed to [pagecache memory allocator]. Only the value returned in the
6014 ** *pHighwater parameter to [sqlite3_status()] is of interest.
6015 ** The value written into the *pCurrent parameter is undefined.</dd>)^
6016 **
6017 ** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt>
6018 ** <dd>This parameter returns the number of allocations used out of the
6019 ** [scratch memory allocator] configured using
6020 ** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not
6021 ** in bytes. Since a single thread may only have one scratch allocation
6022 ** outstanding at time, this parameter also reports the number of threads
6023 ** using scratch memory at the same time.</dd>)^
6024 **
6025 ** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
6026 ** <dd>This parameter returns the number of bytes of scratch memory
6027 ** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH]
6028 ** buffer and where forced to overflow to [sqlite3_malloc()]. The values
6029 ** returned include overflows because the requested allocation was too
6030 ** larger (that is, because the requested allocation was larger than the
6031 ** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer
6032 ** slots were available.
6033 ** </dd>)^
6034 **
6035 ** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
6036 ** <dd>This parameter records the largest memory allocation request
6037 ** handed to [scratch memory allocator]. Only the value returned in the
6038 ** *pHighwater parameter to [sqlite3_status()] is of interest.
6039 ** The value written into the *pCurrent parameter is undefined.</dd>)^
6040 **
6041 ** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
6042 ** <dd>This parameter records the deepest parser stack. It is only
6043 ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
6044 ** </dl>
6045 **
6046 ** New status parameters may be added from time to time.
6047 */
6048 #define SQLITE_STATUS_MEMORY_USED 0
6049 #define SQLITE_STATUS_PAGECACHE_USED 1
6050 #define SQLITE_STATUS_PAGECACHE_OVERFLOW 2
6051 #define SQLITE_STATUS_SCRATCH_USED 3
6052 #define SQLITE_STATUS_SCRATCH_OVERFLOW 4
6053 #define SQLITE_STATUS_MALLOC_SIZE 5
6054 #define SQLITE_STATUS_PARSER_STACK 6
6055 #define SQLITE_STATUS_PAGECACHE_SIZE 7
6056 #define SQLITE_STATUS_SCRATCH_SIZE 8
6057 #define SQLITE_STATUS_MALLOC_COUNT 9
6058
6059 /*
6060 ** CAPI3REF: Database Connection Status
6061 **
6062 ** ^This interface is used to retrieve runtime status information
6063 ** about a single [database connection]. ^The first argument is the
6064 ** database connection object to be interrogated. ^The second argument
6065 ** is an integer constant, taken from the set of
6066 ** [SQLITE_DBSTATUS options], that
6067 ** determines the parameter to interrogate. The set of
6068 ** [SQLITE_DBSTATUS options] is likely
6069 ** to grow in future releases of SQLite.
6070 **
6071 ** ^The current value of the requested parameter is written into *pCur
6072 ** and the highest instantaneous value is written into *pHiwtr. ^If
6073 ** the resetFlg is true, then the highest instantaneous value is
6074 ** reset back down to the current value.
6075 **
6076 ** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
6077 ** non-zero [error code] on failure.
6078 **
6079 ** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
6080 */
6081 SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
6082
6083 /*
6084 ** CAPI3REF: Status Parameters for database connections
6085 ** KEYWORDS: {SQLITE_DBSTATUS options}
6086 **
6087 ** These constants are the available integer "verbs" that can be passed as
6088 ** the second argument to the [sqlite3_db_status()] interface.
6089 **
6090 ** New verbs may be added in future releases of SQLite. Existing verbs
6091 ** might be discontinued. Applications should check the return code from
6092 ** [sqlite3_db_status()] to make sure that the call worked.
6093 ** The [sqlite3_db_status()] interface will return a non-zero error code
6094 ** if a discontinued or unsupported verb is invoked.
6095 **
6096 ** <dl>
6097 ** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
6098 ** <dd>This parameter returns the number of lookaside memory slots currently
6099 ** checked out.</dd>)^
6100 **
6101 ** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
6102 ** <dd>This parameter returns the number malloc attempts that were
6103 ** satisfied using lookaside memory. Only the high-water value is meaningful;
6104 ** the current value is always zero.)^
6105 **
6106 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]]
6107 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
6108 ** <dd>This parameter returns the number malloc attempts that might have
6109 ** been satisfied using lookaside memory but failed due to the amount of
6110 ** memory requested being larger than the lookaside slot size.
6111 ** Only the high-water value is meaningful;
6112 ** the current value is always zero.)^
6113 **
6114 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]]
6115 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
6116 ** <dd>This parameter returns the number malloc attempts that might have
6117 ** been satisfied using lookaside memory but failed due to all lookaside
6118 ** memory already being in use.
6119 ** Only the high-water value is meaningful;
6120 ** the current value is always zero.)^
6121 **
6122 ** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
6123 ** <dd>This parameter returns the approximate number of of bytes of heap
6124 ** memory used by all pager caches associated with the database connection.)^
6125 ** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
6126 **
6127 ** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
6128 ** <dd>This parameter returns the approximate number of of bytes of heap
6129 ** memory used to store the schema for all databases associated
6130 ** with the connection - main, temp, and any [ATTACH]-ed databases.)^
6131 ** ^The full amount of memory used by the schemas is reported, even if the
6132 ** schema memory is shared with other database connections due to
6133 ** [shared cache mode] being enabled.
6134 ** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
6135 **
6136 ** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
6137 ** <dd>This parameter returns the approximate number of of bytes of heap
6138 ** and lookaside memory used by all prepared statements associated with
6139 ** the database connection.)^
6140 ** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
6141 ** </dd>
6142 **
6143 ** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt>
6144 ** <dd>This parameter returns the number of pager cache hits that have
6145 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT
6146 ** is always 0.
6147 ** </dd>
6148 **
6149 ** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt>
6150 ** <dd>This parameter returns the number of pager cache misses that have
6151 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS
6152 ** is always 0.
6153 ** </dd>
6154 **
6155 ** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt>
6156 ** <dd>This parameter returns the number of dirty cache entries that have
6157 ** been written to disk. Specifically, the number of pages written to the
6158 ** wal file in wal mode databases, or the number of pages written to the
6159 ** database file in rollback mode databases. Any pages written as part of
6160 ** transaction rollback or database recovery operations are not included.
6161 ** If an IO or other error occurs while writing a page to disk, the effect
6162 ** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The
6163 ** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0.
6164 ** </dd>
6165 ** </dl>
6166 */
6167 #define SQLITE_DBSTATUS_LOOKASIDE_USED 0
6168 #define SQLITE_DBSTATUS_CACHE_USED 1
6169 #define SQLITE_DBSTATUS_SCHEMA_USED 2
6170 #define SQLITE_DBSTATUS_STMT_USED 3
6171 #define SQLITE_DBSTATUS_LOOKASIDE_HIT 4
6172 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5
6173 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6
6174 #define SQLITE_DBSTATUS_CACHE_HIT 7
6175 #define SQLITE_DBSTATUS_CACHE_MISS 8
6176 #define SQLITE_DBSTATUS_CACHE_WRITE 9
6177 #define SQLITE_DBSTATUS_MAX 9 /* Largest defined DBSTATUS */
6178
6179
6180 /*
6181 ** CAPI3REF: Prepared Statement Status
6182 **
6183 ** ^(Each prepared statement maintains various
6184 ** [SQLITE_STMTSTATUS counters] that measure the number
6185 ** of times it has performed specific operations.)^ These counters can
6186 ** be used to monitor the performance characteristics of the prepared
6187 ** statements. For example, if the number of table steps greatly exceeds
6188 ** the number of table searches or result rows, that would tend to indicate
6189 ** that the prepared statement is using a full table scan rather than
6190 ** an index.
6191 **
6192 ** ^(This interface is used to retrieve and reset counter values from
6193 ** a [prepared statement]. The first argument is the prepared statement
6194 ** object to be interrogated. The second argument
6195 ** is an integer code for a specific [SQLITE_STMTSTATUS counter]
6196 ** to be interrogated.)^
6197 ** ^The current value of the requested counter is returned.
6198 ** ^If the resetFlg is true, then the counter is reset to zero after this
6199 ** interface call returns.
6200 **
6201 ** See also: [sqlite3_status()] and [sqlite3_db_status()].
6202 */
6203 SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
6204
6205 /*
6206 ** CAPI3REF: Status Parameters for prepared statements
6207 ** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters}
6208 **
6209 ** These preprocessor macros define integer codes that name counter
6210 ** values associated with the [sqlite3_stmt_status()] interface.
6211 ** The meanings of the various counters are as follows:
6212 **
6213 ** <dl>
6214 ** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
6215 ** <dd>^This is the number of times that SQLite has stepped forward in
6216 ** a table as part of a full table scan. Large numbers for this counter
6217 ** may indicate opportunities for performance improvement through
6218 ** careful use of indices.</dd>
6219 **
6220 ** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt>
6221 ** <dd>^This is the number of sort operations that have occurred.
6222 ** A non-zero value in this counter may indicate an opportunity to
6223 ** improvement performance through careful use of indices.</dd>
6224 **
6225 ** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
6226 ** <dd>^This is the number of rows inserted into transient indices that
6227 ** were created automatically in order to help joins run faster.
6228 ** A non-zero value in this counter may indicate an opportunity to
6229 ** improvement performance by adding permanent indices that do not
6230 ** need to be reinitialized each time the statement is run.</dd>
6231 ** </dl>
6232 */
6233 #define SQLITE_STMTSTATUS_FULLSCAN_STEP 1
6234 #define SQLITE_STMTSTATUS_SORT 2
6235 #define SQLITE_STMTSTATUS_AUTOINDEX 3
6236
6237 /*
6238 ** CAPI3REF: Custom Page Cache Object
6239 **
6240 ** The sqlite3_pcache type is opaque. It is implemented by
6241 ** the pluggable module. The SQLite core has no knowledge of
6242 ** its size or internal structure and never deals with the
6243 ** sqlite3_pcache object except by holding and passing pointers
6244 ** to the object.
6245 **
6246 ** See [sqlite3_pcache_methods2] for additional information.
6247 */
6248 typedef struct sqlite3_pcache sqlite3_pcache;
6249
6250 /*
6251 ** CAPI3REF: Custom Page Cache Object
6252 **
6253 ** The sqlite3_pcache_page object represents a single page in the
6254 ** page cache. The page cache will allocate instances of this
6255 ** object. Various methods of the page cache use pointers to instances
6256 ** of this object as parameters or as their return value.
6257 **
6258 ** See [sqlite3_pcache_methods2] for additional information.
6259 */
6260 typedef struct sqlite3_pcache_page sqlite3_pcache_page;
6261 struct sqlite3_pcache_page {
6262 void *pBuf; /* The content of the page */
6263 void *pExtra; /* Extra information associated with the page */
6264 };
6265
6266 /*
6267 ** CAPI3REF: Application Defined Page Cache.
6268 ** KEYWORDS: {page cache}
6269 **
6270 ** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can
6271 ** register an alternative page cache implementation by passing in an
6272 ** instance of the sqlite3_pcache_methods2 structure.)^
6273 ** In many applications, most of the heap memory allocated by
6274 ** SQLite is used for the page cache.
6275 ** By implementing a
6276 ** custom page cache using this API, an application can better control
6277 ** the amount of memory consumed by SQLite, the way in which
6278 ** that memory is allocated and released, and the policies used to
6279 ** determine exactly which parts of a database file are cached and for
6280 ** how long.
6281 **
6282 ** The alternative page cache mechanism is an
6283 ** extreme measure that is only needed by the most demanding applications.
6284 ** The built-in page cache is recommended for most uses.
6285 **
6286 ** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an
6287 ** internal buffer by SQLite within the call to [sqlite3_config]. Hence
6288 ** the application may discard the parameter after the call to
6289 ** [sqlite3_config()] returns.)^
6290 **
6291 ** [[the xInit() page cache method]]
6292 ** ^(The xInit() method is called once for each effective
6293 ** call to [sqlite3_initialize()])^
6294 ** (usually only once during the lifetime of the process). ^(The xInit()
6295 ** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^
6296 ** The intent of the xInit() method is to set up global data structures
6297 ** required by the custom page cache implementation.
6298 ** ^(If the xInit() method is NULL, then the
6299 ** built-in default page cache is used instead of the application defined
6300 ** page cache.)^
6301 **
6302 ** [[the xShutdown() page cache method]]
6303 ** ^The xShutdown() method is called by [sqlite3_shutdown()].
6304 ** It can be used to clean up
6305 ** any outstanding resources before process shutdown, if required.
6306 ** ^The xShutdown() method may be NULL.
6307 **
6308 ** ^SQLite automatically serializes calls to the xInit method,
6309 ** so the xInit method need not be threadsafe. ^The
6310 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
6311 ** not need to be threadsafe either. All other methods must be threadsafe
6312 ** in multithreaded applications.
6313 **
6314 ** ^SQLite will never invoke xInit() more than once without an intervening
6315 ** call to xShutdown().
6316 **
6317 ** [[the xCreate() page cache methods]]
6318 ** ^SQLite invokes the xCreate() method to construct a new cache instance.
6319 ** SQLite will typically create one cache instance for each open database file,
6320 ** though this is not guaranteed. ^The
6321 ** first parameter, szPage, is the size in bytes of the pages that must
6322 ** be allocated by the cache. ^szPage will always a power of two. ^The
6323 ** second parameter szExtra is a number of bytes of extra storage
6324 ** associated with each page cache entry. ^The szExtra parameter will
6325 ** a number less than 250. SQLite will use the
6326 ** extra szExtra bytes on each page to store metadata about the underlying
6327 ** database page on disk. The value passed into szExtra depends
6328 ** on the SQLite version, the target platform, and how SQLite was compiled.
6329 ** ^The third argument to xCreate(), bPurgeable, is true if the cache being
6330 ** created will be used to cache database pages of a file stored on disk, or
6331 ** false if it is used for an in-memory database. The cache implementation
6332 ** does not have to do anything special based with the value of bPurgeable;
6333 ** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will
6334 ** never invoke xUnpin() except to deliberately delete a page.
6335 ** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
6336 ** false will always have the "discard" flag set to true.
6337 ** ^Hence, a cache created with bPurgeable false will
6338 ** never contain any unpinned pages.
6339 **
6340 ** [[the xCachesize() page cache method]]
6341 ** ^(The xCachesize() method may be called at any time by SQLite to set the
6342 ** suggested maximum cache-size (number of pages stored by) the cache
6343 ** instance passed as the first argument. This is the value configured using
6344 ** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable
6345 ** parameter, the implementation is not required to do anything with this
6346 ** value; it is advisory only.
6347 **
6348 ** [[the xPagecount() page cache methods]]
6349 ** The xPagecount() method must return the number of pages currently
6350 ** stored in the cache, both pinned and unpinned.
6351 **
6352 ** [[the xFetch() page cache methods]]
6353 ** The xFetch() method locates a page in the cache and returns a pointer to
6354 ** an sqlite3_pcache_page object associated with that page, or a NULL pointer.
6355 ** The pBuf element of the returned sqlite3_pcache_page object will be a
6356 ** pointer to a buffer of szPage bytes used to store the content of a
6357 ** single database page. The pExtra element of sqlite3_pcache_page will be
6358 ** a pointer to the szExtra bytes of extra storage that SQLite has requested
6359 ** for each entry in the page cache.
6360 **
6361 ** The page to be fetched is determined by the key. ^The minimum key value
6362 ** is 1. After it has been retrieved using xFetch, the page is considered
6363 ** to be "pinned".
6364 **
6365 ** If the requested page is already in the page cache, then the page cache
6366 ** implementation must return a pointer to the page buffer with its content
6367 ** intact. If the requested page is not already in the cache, then the
6368 ** cache implementation should use the value of the createFlag
6369 ** parameter to help it determined what action to take:
6370 **
6371 ** <table border=1 width=85% align=center>
6372 ** <tr><th> createFlag <th> Behaviour when page is not already in cache
6373 ** <tr><td> 0 <td> Do not allocate a new page. Return NULL.
6374 ** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
6375 ** Otherwise return NULL.
6376 ** <tr><td> 2 <td> Make every effort to allocate a new page. Only return
6377 ** NULL if allocating a new page is effectively impossible.
6378 ** </table>
6379 **
6380 ** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite
6381 ** will only use a createFlag of 2 after a prior call with a createFlag of 1
6382 ** failed.)^ In between the to xFetch() calls, SQLite may
6383 ** attempt to unpin one or more cache pages by spilling the content of
6384 ** pinned pages to disk and synching the operating system disk cache.
6385 **
6386 ** [[the xUnpin() page cache method]]
6387 ** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
6388 ** as its second argument. If the third parameter, discard, is non-zero,
6389 ** then the page must be evicted from the cache.
6390 ** ^If the discard parameter is
6391 ** zero, then the page may be discarded or retained at the discretion of
6392 ** page cache implementation. ^The page cache implementation
6393 ** may choose to evict unpinned pages at any time.
6394 **
6395 ** The cache must not perform any reference counting. A single
6396 ** call to xUnpin() unpins the page regardless of the number of prior calls
6397 ** to xFetch().
6398 **
6399 ** [[the xRekey() page cache methods]]
6400 ** The xRekey() method is used to change the key value associated with the
6401 ** page passed as the second argument. If the cache
6402 ** previously contains an entry associated with newKey, it must be
6403 ** discarded. ^Any prior cache entry associated with newKey is guaranteed not
6404 ** to be pinned.
6405 **
6406 ** When SQLite calls the xTruncate() method, the cache must discard all
6407 ** existing cache entries with page numbers (keys) greater than or equal
6408 ** to the value of the iLimit parameter passed to xTruncate(). If any
6409 ** of these pages are pinned, they are implicitly unpinned, meaning that
6410 ** they can be safely discarded.
6411 **
6412 ** [[the xDestroy() page cache method]]
6413 ** ^The xDestroy() method is used to delete a cache allocated by xCreate().
6414 ** All resources associated with the specified cache should be freed. ^After
6415 ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
6416 ** handle invalid, and will not use it with any other sqlite3_pcache_methods2
6417 ** functions.
6418 **
6419 ** [[the xShrink() page cache method]]
6420 ** ^SQLite invokes the xShrink() method when it wants the page cache to
6421 ** free up as much of heap memory as possible. The page cache implementation
6422 ** is not obligated to free any memory, but well-behaved implementations should
6423 ** do their best.
6424 */
6425 typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
6426 struct sqlite3_pcache_methods2 {
6427 int iVersion;
6428 void *pArg;
6429 int (*xInit)(void*);
6430 void (*xShutdown)(void*);
6431 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
6432 void (*xCachesize)(sqlite3_pcache*, int nCachesize);
6433 int (*xPagecount)(sqlite3_pcache*);
6434 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
6435 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
6436 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*,
6437 unsigned oldKey, unsigned newKey);
6438 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
6439 void (*xDestroy)(sqlite3_pcache*);
6440 void (*xShrink)(sqlite3_pcache*);
6441 };
6442
6443 /*
6444 ** This is the obsolete pcache_methods object that has now been replaced
6445 ** by sqlite3_pcache_methods2. This object is not used by SQLite. It is
6446 ** retained in the header file for backwards compatibility only.
6447 */
6448 typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
6449 struct sqlite3_pcache_methods {
6450 void *pArg;
6451 int (*xInit)(void*);
6452 void (*xShutdown)(void*);
6453 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
6454 void (*xCachesize)(sqlite3_pcache*, int nCachesize);
6455 int (*xPagecount)(sqlite3_pcache*);
6456 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
6457 void (*xUnpin)(sqlite3_pcache*, void*, int discard);
6458 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
6459 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
6460 void (*xDestroy)(sqlite3_pcache*);
6461 };
6462
6463
6464 /*
6465 ** CAPI3REF: Online Backup Object
6466 **
6467 ** The sqlite3_backup object records state information about an ongoing
6468 ** online backup operation. ^The sqlite3_backup object is created by
6469 ** a call to [sqlite3_backup_init()] and is destroyed by a call to
6470 ** [sqlite3_backup_finish()].
6471 **
6472 ** See Also: [Using the SQLite Online Backup API]
6473 */
6474 typedef struct sqlite3_backup sqlite3_backup;
6475
6476 /*
6477 ** CAPI3REF: Online Backup API.
6478 **
6479 ** The backup API copies the content of one database into another.
6480 ** It is useful either for creating backups of databases or
6481 ** for copying in-memory databases to or from persistent files.
6482 **
6483 ** See Also: [Using the SQLite Online Backup API]
6484 **
6485 ** ^SQLite holds a write transaction open on the destination database file
6486 ** for the duration of the backup operation.
6487 ** ^The source database is read-locked only while it is being read;
6488 ** it is not locked continuously for the entire backup operation.
6489 ** ^Thus, the backup may be performed on a live source database without
6490 ** preventing other database connections from
6491 ** reading or writing to the source database while the backup is underway.
6492 **
6493 ** ^(To perform a backup operation:
6494 ** <ol>
6495 ** <li><b>sqlite3_backup_init()</b> is called once to initialize the
6496 ** backup,
6497 ** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
6498 ** the data between the two databases, and finally
6499 ** <li><b>sqlite3_backup_finish()</b> is called to release all resources
6500 ** associated with the backup operation.
6501 ** </ol>)^
6502 ** There should be exactly one call to sqlite3_backup_finish() for each
6503 ** successful call to sqlite3_backup_init().
6504 **
6505 ** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
6506 **
6507 ** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
6508 ** [database connection] associated with the destination database
6509 ** and the database name, respectively.
6510 ** ^The database name is "main" for the main database, "temp" for the
6511 ** temporary database, or the name specified after the AS keyword in
6512 ** an [ATTACH] statement for an attached database.
6513 ** ^The S and M arguments passed to
6514 ** sqlite3_backup_init(D,N,S,M) identify the [database connection]
6515 ** and database name of the source database, respectively.
6516 ** ^The source and destination [database connections] (parameters S and D)
6517 ** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
6518 ** an error.
6519 **
6520 ** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
6521 ** returned and an error code and error message are stored in the
6522 ** destination [database connection] D.
6523 ** ^The error code and message for the failed call to sqlite3_backup_init()
6524 ** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
6525 ** [sqlite3_errmsg16()] functions.
6526 ** ^A successful call to sqlite3_backup_init() returns a pointer to an
6527 ** [sqlite3_backup] object.
6528 ** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
6529 ** sqlite3_backup_finish() functions to perform the specified backup
6530 ** operation.
6531 **
6532 ** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
6533 **
6534 ** ^Function sqlite3_backup_step(B,N) will copy up to N pages between
6535 ** the source and destination databases specified by [sqlite3_backup] object B.
6536 ** ^If N is negative, all remaining source pages are copied.
6537 ** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
6538 ** are still more pages to be copied, then the function returns [SQLITE_OK].
6539 ** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
6540 ** from source to destination, then it returns [SQLITE_DONE].
6541 ** ^If an error occurs while running sqlite3_backup_step(B,N),
6542 ** then an [error code] is returned. ^As well as [SQLITE_OK] and
6543 ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
6544 ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
6545 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
6546 **
6547 ** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
6548 ** <ol>
6549 ** <li> the destination database was opened read-only, or
6550 ** <li> the destination database is using write-ahead-log journaling
6551 ** and the destination and source page sizes differ, or
6552 ** <li> the destination database is an in-memory database and the
6553 ** destination and source page sizes differ.
6554 ** </ol>)^
6555 **
6556 ** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
6557 ** the [sqlite3_busy_handler | busy-handler function]
6558 ** is invoked (if one is specified). ^If the
6559 ** busy-handler returns non-zero before the lock is available, then
6560 ** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
6561 ** sqlite3_backup_step() can be retried later. ^If the source
6562 ** [database connection]
6563 ** is being used to write to the source database when sqlite3_backup_step()
6564 ** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
6565 ** case the call to sqlite3_backup_step() can be retried later on. ^(If
6566 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
6567 ** [SQLITE_READONLY] is returned, then
6568 ** there is no point in retrying the call to sqlite3_backup_step(). These
6569 ** errors are considered fatal.)^ The application must accept
6570 ** that the backup operation has failed and pass the backup operation handle
6571 ** to the sqlite3_backup_finish() to release associated resources.
6572 **
6573 ** ^The first call to sqlite3_backup_step() obtains an exclusive lock
6574 ** on the destination file. ^The exclusive lock is not released until either
6575 ** sqlite3_backup_finish() is called or the backup operation is complete
6576 ** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to
6577 ** sqlite3_backup_step() obtains a [shared lock] on the source database that
6578 ** lasts for the duration of the sqlite3_backup_step() call.
6579 ** ^Because the source database is not locked between calls to
6580 ** sqlite3_backup_step(), the source database may be modified mid-way
6581 ** through the backup process. ^If the source database is modified by an
6582 ** external process or via a database connection other than the one being
6583 ** used by the backup operation, then the backup will be automatically
6584 ** restarted by the next call to sqlite3_backup_step(). ^If the source
6585 ** database is modified by the using the same database connection as is used
6586 ** by the backup operation, then the backup database is automatically
6587 ** updated at the same time.
6588 **
6589 ** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
6590 **
6591 ** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the
6592 ** application wishes to abandon the backup operation, the application
6593 ** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
6594 ** ^The sqlite3_backup_finish() interfaces releases all
6595 ** resources associated with the [sqlite3_backup] object.
6596 ** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
6597 ** active write-transaction on the destination database is rolled back.
6598 ** The [sqlite3_backup] object is invalid
6599 ** and may not be used following a call to sqlite3_backup_finish().
6600 **
6601 ** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
6602 ** sqlite3_backup_step() errors occurred, regardless or whether or not
6603 ** sqlite3_backup_step() completed.
6604 ** ^If an out-of-memory condition or IO error occurred during any prior
6605 ** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
6606 ** sqlite3_backup_finish() returns the corresponding [error code].
6607 **
6608 ** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
6609 ** is not a permanent error and does not affect the return value of
6610 ** sqlite3_backup_finish().
6611 **
6612 ** [[sqlite3_backup__remaining()]] [[sqlite3_backup_pagecount()]]
6613 ** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
6614 **
6615 ** ^Each call to sqlite3_backup_step() sets two values inside
6616 ** the [sqlite3_backup] object: the number of pages still to be backed
6617 ** up and the total number of pages in the source database file.
6618 ** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces
6619 ** retrieve these two values, respectively.
6620 **
6621 ** ^The values returned by these functions are only updated by
6622 ** sqlite3_backup_step(). ^If the source database is modified during a backup
6623 ** operation, then the values are not updated to account for any extra
6624 ** pages that need to be updated or the size of the source database file
6625 ** changing.
6626 **
6627 ** <b>Concurrent Usage of Database Handles</b>
6628 **
6629 ** ^The source [database connection] may be used by the application for other
6630 ** purposes while a backup operation is underway or being initialized.
6631 ** ^If SQLite is compiled and configured to support threadsafe database
6632 ** connections, then the source database connection may be used concurrently
6633 ** from within other threads.
6634 **
6635 ** However, the application must guarantee that the destination
6636 ** [database connection] is not passed to any other API (by any thread) after
6637 ** sqlite3_backup_init() is called and before the corresponding call to
6638 ** sqlite3_backup_finish(). SQLite does not currently check to see
6639 ** if the application incorrectly accesses the destination [database connection]
6640 ** and so no error code is reported, but the operations may malfunction
6641 ** nevertheless. Use of the destination database connection while a
6642 ** backup is in progress might also also cause a mutex deadlock.
6643 **
6644 ** If running in [shared cache mode], the application must
6645 ** guarantee that the shared cache used by the destination database
6646 ** is not accessed while the backup is running. In practice this means
6647 ** that the application must guarantee that the disk file being
6648 ** backed up to is not accessed by any connection within the process,
6649 ** not just the specific connection that was passed to sqlite3_backup_init().
6650 **
6651 ** The [sqlite3_backup] object itself is partially threadsafe. Multiple
6652 ** threads may safely make multiple concurrent calls to sqlite3_backup_step().
6653 ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
6654 ** APIs are not strictly speaking threadsafe. If they are invoked at the
6655 ** same time as another thread is invoking sqlite3_backup_step() it is
6656 ** possible that they return invalid values.
6657 */
6658 SQLITE_API sqlite3_backup *sqlite3_backup_init(
6659 sqlite3 *pDest, /* Destination database handle */
6660 const char *zDestName, /* Destination database name */
6661 sqlite3 *pSource, /* Source database handle */
6662 const char *zSourceName /* Source database name */
6663 );
6664 SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage);
6665 SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p);
6666 SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p);
6667 SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p);
6668
6669 /*
6670 ** CAPI3REF: Unlock Notification
6671 **
6672 ** ^When running in shared-cache mode, a database operation may fail with
6673 ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
6674 ** individual tables within the shared-cache cannot be obtained. See
6675 ** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
6676 ** ^This API may be used to register a callback that SQLite will invoke
6677 ** when the connection currently holding the required lock relinquishes it.
6678 ** ^This API is only available if the library was compiled with the
6679 ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
6680 **
6681 ** See Also: [Using the SQLite Unlock Notification Feature].
6682 **
6683 ** ^Shared-cache locks are released when a database connection concludes
6684 ** its current transaction, either by committing it or rolling it back.
6685 **
6686 ** ^When a connection (known as the blocked connection) fails to obtain a
6687 ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
6688 ** identity of the database connection (the blocking connection) that
6689 ** has locked the required resource is stored internally. ^After an
6690 ** application receives an SQLITE_LOCKED error, it may call the
6691 ** sqlite3_unlock_notify() method with the blocked connection handle as
6692 ** the first argument to register for a callback that will be invoked
6693 ** when the blocking connections current transaction is concluded. ^The
6694 ** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
6695 ** call that concludes the blocking connections transaction.
6696 **
6697 ** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
6698 ** there is a chance that the blocking connection will have already
6699 ** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
6700 ** If this happens, then the specified callback is invoked immediately,
6701 ** from within the call to sqlite3_unlock_notify().)^
6702 **
6703 ** ^If the blocked connection is attempting to obtain a write-lock on a
6704 ** shared-cache table, and more than one other connection currently holds
6705 ** a read-lock on the same table, then SQLite arbitrarily selects one of
6706 ** the other connections to use as the blocking connection.
6707 **
6708 ** ^(There may be at most one unlock-notify callback registered by a
6709 ** blocked connection. If sqlite3_unlock_notify() is called when the
6710 ** blocked connection already has a registered unlock-notify callback,
6711 ** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
6712 ** called with a NULL pointer as its second argument, then any existing
6713 ** unlock-notify callback is canceled. ^The blocked connections
6714 ** unlock-notify callback may also be canceled by closing the blocked
6715 ** connection using [sqlite3_close()].
6716 **
6717 ** The unlock-notify callback is not reentrant. If an application invokes
6718 ** any sqlite3_xxx API functions from within an unlock-notify callback, a
6719 ** crash or deadlock may be the result.
6720 **
6721 ** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
6722 ** returns SQLITE_OK.
6723 **
6724 ** <b>Callback Invocation Details</b>
6725 **
6726 ** When an unlock-notify callback is registered, the application provides a
6727 ** single void* pointer that is passed to the callback when it is invoked.
6728 ** However, the signature of the callback function allows SQLite to pass
6729 ** it an array of void* context pointers. The first argument passed to
6730 ** an unlock-notify callback is a pointer to an array of void* pointers,
6731 ** and the second is the number of entries in the array.
6732 **
6733 ** When a blocking connections transaction is concluded, there may be
6734 ** more than one blocked connection that has registered for an unlock-notify
6735 ** callback. ^If two or more such blocked connections have specified the
6736 ** same callback function, then instead of invoking the callback function
6737 ** multiple times, it is invoked once with the set of void* context pointers
6738 ** specified by the blocked connections bundled together into an array.
6739 ** This gives the application an opportunity to prioritize any actions
6740 ** related to the set of unblocked database connections.
6741 **
6742 ** <b>Deadlock Detection</b>
6743 **
6744 ** Assuming that after registering for an unlock-notify callback a
6745 ** database waits for the callback to be issued before taking any further
6746 ** action (a reasonable assumption), then using this API may cause the
6747 ** application to deadlock. For example, if connection X is waiting for
6748 ** connection Y's transaction to be concluded, and similarly connection
6749 ** Y is waiting on connection X's transaction, then neither connection
6750 ** will proceed and the system may remain deadlocked indefinitely.
6751 **
6752 ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
6753 ** detection. ^If a given call to sqlite3_unlock_notify() would put the
6754 ** system in a deadlocked state, then SQLITE_LOCKED is returned and no
6755 ** unlock-notify callback is registered. The system is said to be in
6756 ** a deadlocked state if connection A has registered for an unlock-notify
6757 ** callback on the conclusion of connection B's transaction, and connection
6758 ** B has itself registered for an unlock-notify callback when connection
6759 ** A's transaction is concluded. ^Indirect deadlock is also detected, so
6760 ** the system is also considered to be deadlocked if connection B has
6761 ** registered for an unlock-notify callback on the conclusion of connection
6762 ** C's transaction, where connection C is waiting on connection A. ^Any
6763 ** number of levels of indirection are allowed.
6764 **
6765 ** <b>The "DROP TABLE" Exception</b>
6766 **
6767 ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost
6768 ** always appropriate to call sqlite3_unlock_notify(). There is however,
6769 ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
6770 ** SQLite checks if there are any currently executing SELECT statements
6771 ** that belong to the same connection. If there are, SQLITE_LOCKED is
6772 ** returned. In this case there is no "blocking connection", so invoking
6773 ** sqlite3_unlock_notify() results in the unlock-notify callback being
6774 ** invoked immediately. If the application then re-attempts the "DROP TABLE"
6775 ** or "DROP INDEX" query, an infinite loop might be the result.
6776 **
6777 ** One way around this problem is to check the extended error code returned
6778 ** by an sqlite3_step() call. ^(If there is a blocking connection, then the
6779 ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
6780 ** the special "DROP TABLE/INDEX" case, the extended error code is just
6781 ** SQLITE_LOCKED.)^
6782 */
6783 SQLITE_API int sqlite3_unlock_notify(
6784 sqlite3 *pBlocked, /* Waiting connection */
6785 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */
6786 void *pNotifyArg /* Argument to pass to xNotify */
6787 );
6788
6789
6790 /*
6791 ** CAPI3REF: String Comparison
6792 **
6793 ** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications
6794 ** and extensions to compare the contents of two buffers containing UTF-8
6795 ** strings in a case-independent fashion, using the same definition of "case
6796 ** independence" that SQLite uses internally when comparing identifiers.
6797 */
6798 SQLITE_API int sqlite3_stricmp(const char *, const char *);
6799 SQLITE_API int sqlite3_strnicmp(const char *, const char *, int);
6800
6801 /*
6802 ** CAPI3REF: Error Logging Interface
6803 **
6804 ** ^The [sqlite3_log()] interface writes a message into the error log
6805 ** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
6806 ** ^If logging is enabled, the zFormat string and subsequent arguments are
6807 ** used with [sqlite3_snprintf()] to generate the final output string.
6808 **
6809 ** The sqlite3_log() interface is intended for use by extensions such as
6810 ** virtual tables, collating functions, and SQL functions. While there is
6811 ** nothing to prevent an application from calling sqlite3_log(), doing so
6812 ** is considered bad form.
6813 **
6814 ** The zFormat string must not be NULL.
6815 **
6816 ** To avoid deadlocks and other threading problems, the sqlite3_log() routine
6817 ** will not use dynamically allocated memory. The log message is stored in
6818 ** a fixed-length buffer on the stack. If the log message is longer than
6819 ** a few hundred characters, it will be truncated to the length of the
6820 ** buffer.
6821 */
6822 SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...);
6823
6824 /*
6825 ** CAPI3REF: Write-Ahead Log Commit Hook
6826 **
6827 ** ^The [sqlite3_wal_hook()] function is used to register a callback that
6828 ** will be invoked each time a database connection commits data to a
6829 ** [write-ahead log] (i.e. whenever a transaction is committed in
6830 ** [journal_mode | journal_mode=WAL mode]).
6831 **
6832 ** ^The callback is invoked by SQLite after the commit has taken place and
6833 ** the associated write-lock on the database released, so the implementation
6834 ** may read, write or [checkpoint] the database as required.
6835 **
6836 ** ^The first parameter passed to the callback function when it is invoked
6837 ** is a copy of the third parameter passed to sqlite3_wal_hook() when
6838 ** registering the callback. ^The second is a copy of the database handle.
6839 ** ^The third parameter is the name of the database that was written to -
6840 ** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
6841 ** is the number of pages currently in the write-ahead log file,
6842 ** including those that were just committed.
6843 **
6844 ** The callback function should normally return [SQLITE_OK]. ^If an error
6845 ** code is returned, that error will propagate back up through the
6846 ** SQLite code base to cause the statement that provoked the callback
6847 ** to report an error, though the commit will have still occurred. If the
6848 ** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
6849 ** that does not correspond to any valid SQLite error code, the results
6850 ** are undefined.
6851 **
6852 ** A single database handle may have at most a single write-ahead log callback
6853 ** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
6854 ** previously registered write-ahead log callback. ^Note that the
6855 ** [sqlite3_wal_autocheckpoint()] interface and the
6856 ** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
6857 ** those overwrite any prior [sqlite3_wal_hook()] settings.
6858 */
6859 SQLITE_API void *sqlite3_wal_hook(
6860 sqlite3*,
6861 int(*)(void *,sqlite3*,const char*,int),
6862 void*
6863 );
6864
6865 /*
6866 ** CAPI3REF: Configure an auto-checkpoint
6867 **
6868 ** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
6869 ** [sqlite3_wal_hook()] that causes any database on [database connection] D
6870 ** to automatically [checkpoint]
6871 ** after committing a transaction if there are N or
6872 ** more frames in the [write-ahead log] file. ^Passing zero or
6873 ** a negative value as the nFrame parameter disables automatic
6874 ** checkpoints entirely.
6875 **
6876 ** ^The callback registered by this function replaces any existing callback
6877 ** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback
6878 ** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
6879 ** configured by this function.
6880 **
6881 ** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
6882 ** from SQL.
6883 **
6884 ** ^Every new [database connection] defaults to having the auto-checkpoint
6885 ** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
6886 ** pages. The use of this interface
6887 ** is only necessary if the default setting is found to be suboptimal
6888 ** for a particular application.
6889 */
6890 SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
6891
6892 /*
6893 ** CAPI3REF: Checkpoint a database
6894 **
6895 ** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X
6896 ** on [database connection] D to be [checkpointed]. ^If X is NULL or an
6897 ** empty string, then a checkpoint is run on all databases of
6898 ** connection D. ^If the database connection D is not in
6899 ** [WAL | write-ahead log mode] then this interface is a harmless no-op.
6900 **
6901 ** ^The [wal_checkpoint pragma] can be used to invoke this interface
6902 ** from SQL. ^The [sqlite3_wal_autocheckpoint()] interface and the
6903 ** [wal_autocheckpoint pragma] can be used to cause this interface to be
6904 ** run whenever the WAL reaches a certain size threshold.
6905 **
6906 ** See also: [sqlite3_wal_checkpoint_v2()]
6907 */
6908 SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
6909
6910 /*
6911 ** CAPI3REF: Checkpoint a database
6912 **
6913 ** Run a checkpoint operation on WAL database zDb attached to database
6914 ** handle db. The specific operation is determined by the value of the
6915 ** eMode parameter:
6916 **
6917 ** <dl>
6918 ** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
6919 ** Checkpoint as many frames as possible without waiting for any database
6920 ** readers or writers to finish. Sync the db file if all frames in the log
6921 ** are checkpointed. This mode is the same as calling
6922 ** sqlite3_wal_checkpoint(). The busy-handler callback is never invoked.
6923 **
6924 ** <dt>SQLITE_CHECKPOINT_FULL<dd>
6925 ** This mode blocks (calls the busy-handler callback) until there is no
6926 ** database writer and all readers are reading from the most recent database
6927 ** snapshot. It then checkpoints all frames in the log file and syncs the
6928 ** database file. This call blocks database writers while it is running,
6929 ** but not database readers.
6930 **
6931 ** <dt>SQLITE_CHECKPOINT_RESTART<dd>
6932 ** This mode works the same way as SQLITE_CHECKPOINT_FULL, except after
6933 ** checkpointing the log file it blocks (calls the busy-handler callback)
6934 ** until all readers are reading from the database file only. This ensures
6935 ** that the next client to write to the database file restarts the log file
6936 ** from the beginning. This call blocks database writers while it is running,
6937 ** but not database readers.
6938 ** </dl>
6939 **
6940 ** If pnLog is not NULL, then *pnLog is set to the total number of frames in
6941 ** the log file before returning. If pnCkpt is not NULL, then *pnCkpt is set to
6942 ** the total number of checkpointed frames (including any that were already
6943 ** checkpointed when this function is called). *pnLog and *pnCkpt may be
6944 ** populated even if sqlite3_wal_checkpoint_v2() returns other than SQLITE_OK.
6945 ** If no values are available because of an error, they are both set to -1
6946 ** before returning to communicate this to the caller.
6947 **
6948 ** All calls obtain an exclusive "checkpoint" lock on the database file. If
6949 ** any other process is running a checkpoint operation at the same time, the
6950 ** lock cannot be obtained and SQLITE_BUSY is returned. Even if there is a
6951 ** busy-handler configured, it will not be invoked in this case.
6952 **
6953 ** The SQLITE_CHECKPOINT_FULL and RESTART modes also obtain the exclusive
6954 ** "writer" lock on the database file. If the writer lock cannot be obtained
6955 ** immediately, and a busy-handler is configured, it is invoked and the writer
6956 ** lock retried until either the busy-handler returns 0 or the lock is
6957 ** successfully obtained. The busy-handler is also invoked while waiting for
6958 ** database readers as described above. If the busy-handler returns 0 before
6959 ** the writer lock is obtained or while waiting for database readers, the
6960 ** checkpoint operation proceeds from that point in the same way as
6961 ** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible
6962 ** without blocking any further. SQLITE_BUSY is returned in this case.
6963 **
6964 ** If parameter zDb is NULL or points to a zero length string, then the
6965 ** specified operation is attempted on all WAL databases. In this case the
6966 ** values written to output parameters *pnLog and *pnCkpt are undefined. If
6967 ** an SQLITE_BUSY error is encountered when processing one or more of the
6968 ** attached WAL databases, the operation is still attempted on any remaining
6969 ** attached databases and SQLITE_BUSY is returned to the caller. If any other
6970 ** error occurs while processing an attached database, processing is abandoned
6971 ** and the error code returned to the caller immediately. If no error
6972 ** (SQLITE_BUSY or otherwise) is encountered while processing the attached
6973 ** databases, SQLITE_OK is returned.
6974 **
6975 ** If database zDb is the name of an attached database that is not in WAL
6976 ** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. If
6977 ** zDb is not NULL (or a zero length string) and is not the name of any
6978 ** attached database, SQLITE_ERROR is returned to the caller.
6979 */
6980 SQLITE_API int sqlite3_wal_checkpoint_v2(
6981 sqlite3 *db, /* Database handle */
6982 const char *zDb, /* Name of attached database (or NULL) */
6983 int eMode, /* SQLITE_CHECKPOINT_* value */
6984 int *pnLog, /* OUT: Size of WAL log in frames */
6985 int *pnCkpt /* OUT: Total number of frames checkpointed */
6986 );
6987
6988 /*
6989 ** CAPI3REF: Checkpoint operation parameters
6990 **
6991 ** These constants can be used as the 3rd parameter to
6992 ** [sqlite3_wal_checkpoint_v2()]. See the [sqlite3_wal_checkpoint_v2()]
6993 ** documentation for additional information about the meaning and use of
6994 ** each of these values.
6995 */
6996 #define SQLITE_CHECKPOINT_PASSIVE 0
6997 #define SQLITE_CHECKPOINT_FULL 1
6998 #define SQLITE_CHECKPOINT_RESTART 2
6999
7000 /*
7001 ** CAPI3REF: Virtual Table Interface Configuration
7002 **
7003 ** This function may be called by either the [xConnect] or [xCreate] method
7004 ** of a [virtual table] implementation to configure
7005 ** various facets of the virtual table interface.
7006 **
7007 ** If this interface is invoked outside the context of an xConnect or
7008 ** xCreate virtual table method then the behavior is undefined.
7009 **
7010 ** At present, there is only one option that may be configured using
7011 ** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options
7012 ** may be added in the future.
7013 */
7014 SQLITE_API int sqlite3_vtab_config(sqlite3*, int op, ...);
7015
7016 /*
7017 ** CAPI3REF: Virtual Table Configuration Options
7018 **
7019 ** These macros define the various options to the
7020 ** [sqlite3_vtab_config()] interface that [virtual table] implementations
7021 ** can use to customize and optimize their behavior.
7022 **
7023 ** <dl>
7024 ** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT
7025 ** <dd>Calls of the form
7026 ** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
7027 ** where X is an integer. If X is zero, then the [virtual table] whose
7028 ** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not
7029 ** support constraints. In this configuration (which is the default) if
7030 ** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire
7031 ** statement is rolled back as if [ON CONFLICT | OR ABORT] had been
7032 ** specified as part of the users SQL statement, regardless of the actual
7033 ** ON CONFLICT mode specified.
7034 **
7035 ** If X is non-zero, then the virtual table implementation guarantees
7036 ** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before
7037 ** any modifications to internal or persistent data structures have been made.
7038 ** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite
7039 ** is able to roll back a statement or database transaction, and abandon
7040 ** or continue processing the current SQL statement as appropriate.
7041 ** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns
7042 ** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode
7043 ** had been ABORT.
7044 **
7045 ** Virtual table implementations that are required to handle OR REPLACE
7046 ** must do so within the [xUpdate] method. If a call to the
7047 ** [sqlite3_vtab_on_conflict()] function indicates that the current ON
7048 ** CONFLICT policy is REPLACE, the virtual table implementation should
7049 ** silently replace the appropriate rows within the xUpdate callback and
7050 ** return SQLITE_OK. Or, if this is not possible, it may return
7051 ** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT
7052 ** constraint handling.
7053 ** </dl>
7054 */
7055 #define SQLITE_VTAB_CONSTRAINT_SUPPORT 1
7056
7057 /*
7058 ** CAPI3REF: Determine The Virtual Table Conflict Policy
7059 **
7060 ** This function may only be called from within a call to the [xUpdate] method
7061 ** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The
7062 ** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
7063 ** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
7064 ** of the SQL statement that triggered the call to the [xUpdate] method of the
7065 ** [virtual table].
7066 */
7067 SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *);
7068
7069 /*
7070 ** CAPI3REF: Conflict resolution modes
7071 **
7072 ** These constants are returned by [sqlite3_vtab_on_conflict()] to
7073 ** inform a [virtual table] implementation what the [ON CONFLICT] mode
7074 ** is for the SQL statement being evaluated.
7075 **
7076 ** Note that the [SQLITE_IGNORE] constant is also used as a potential
7077 ** return value from the [sqlite3_set_authorizer()] callback and that
7078 ** [SQLITE_ABORT] is also a [result code].
7079 */
7080 #define SQLITE_ROLLBACK 1
7081 /* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
7082 #define SQLITE_FAIL 3
7083 /* #define SQLITE_ABORT 4 // Also an error code */
7084 #define SQLITE_REPLACE 5
7085
7086
7087
7088 /*
7089 ** Undo the hack that converts floating point types to integer for
7090 ** builds on processors without floating point support.
7091 */
7092 #ifdef SQLITE_OMIT_FLOATING_POINT
7093 # undef double
7094 #endif
7095
7096 #ifdef __cplusplus
7097 } /* End of the 'extern "C"' block */
7098 #endif
7099 #endif
7100
7101 /*
7102 ** 2010 August 30
7103 **
7104 ** The author disclaims copyright to this source code. In place of
7105 ** a legal notice, here is a blessing:
7106 **
7107 ** May you do good and not evil.
7108 ** May you find forgiveness for yourself and forgive others.
7109 ** May you share freely, never taking more than you give.
7110 **
7111 *************************************************************************
7112 */
7113
7114 #ifndef _SQLITE3RTREE_H_
7115 #define _SQLITE3RTREE_H_
7116
7117
7118 #ifdef __cplusplus
7119 extern "C" {
7120 #endif
7121
7122 typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry;
7123
7124 /*
7125 ** Register a geometry callback named zGeom that can be used as part of an
7126 ** R-Tree geometry query as follows:
7127 **
7128 ** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...)
7129 */
7130 SQLITE_API int sqlite3_rtree_geometry_callback(
7131 sqlite3 *db,
7132 const char *zGeom,
7133 #ifdef SQLITE_RTREE_INT_ONLY
7134 int (*xGeom)(sqlite3_rtree_geometry*, int n, sqlite3_int64 *a, int *pRes),
7135 #else
7136 int (*xGeom)(sqlite3_rtree_geometry*, int n, double *a, int *pRes),
7137 #endif
7138 void *pContext
7139 );
7140
7141
7142 /*
7143 ** A pointer to a structure of the following type is passed as the first
7144 ** argument to callbacks registered using rtree_geometry_callback().
7145 */
7146 struct sqlite3_rtree_geometry {
7147 void *pContext; /* Copy of pContext passed to s_r_g_c() */
7148 int nParam; /* Size of array aParam[] */
7149 double *aParam; /* Parameters passed to SQL geom function */
7150 void *pUser; /* Callback implementation user data */
7151 void (*xDelUser)(void *); /* Called by SQLite to clean up pUser */
7152 };
7153
7154
7155 #ifdef __cplusplus
7156 } /* end of the 'extern "C"' block */
7157 #endif
7158
7159 #endif /* ifndef _SQLITE3RTREE_H_ */
7160

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