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comparison include/sqlite3.h @ 0:c174ac668e9f
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date | Tue, 05 Apr 2011 18:44:57 +0900 |
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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 evalutes 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 "3.7.0.1" | |
111 #define SQLITE_VERSION_NUMBER 3007000 | |
112 #define SQLITE_SOURCE_ID "2010-08-04 12:31:11 042a1abb030a0711386add7eb6e10832cc8b0f57" | |
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 interating | |
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 specifing 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 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 ** is its destructor. There are many other interfaces (such as | |
223 ** [sqlite3_prepare_v2()], [sqlite3_create_function()], and | |
224 ** [sqlite3_busy_timeout()] to name but three) that are methods on an | |
225 ** sqlite3 object. | |
226 */ | |
227 typedef struct sqlite3 sqlite3; | |
228 | |
229 /* | |
230 ** CAPI3REF: 64-Bit Integer Types | |
231 ** KEYWORDS: sqlite_int64 sqlite_uint64 | |
232 ** | |
233 ** Because there is no cross-platform way to specify 64-bit integer types | |
234 ** SQLite includes typedefs for 64-bit signed and unsigned integers. | |
235 ** | |
236 ** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. | |
237 ** The sqlite_int64 and sqlite_uint64 types are supported for backwards | |
238 ** compatibility only. | |
239 ** | |
240 ** ^The sqlite3_int64 and sqlite_int64 types can store integer values | |
241 ** between -9223372036854775808 and +9223372036854775807 inclusive. ^The | |
242 ** sqlite3_uint64 and sqlite_uint64 types can store integer values | |
243 ** between 0 and +18446744073709551615 inclusive. | |
244 */ | |
245 #ifdef SQLITE_INT64_TYPE | |
246 typedef SQLITE_INT64_TYPE sqlite_int64; | |
247 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; | |
248 #elif defined(_MSC_VER) || defined(__BORLANDC__) | |
249 typedef __int64 sqlite_int64; | |
250 typedef unsigned __int64 sqlite_uint64; | |
251 #else | |
252 typedef long long int sqlite_int64; | |
253 typedef unsigned long long int sqlite_uint64; | |
254 #endif | |
255 typedef sqlite_int64 sqlite3_int64; | |
256 typedef sqlite_uint64 sqlite3_uint64; | |
257 | |
258 /* | |
259 ** If compiling for a processor that lacks floating point support, | |
260 ** substitute integer for floating-point. | |
261 */ | |
262 #ifdef SQLITE_OMIT_FLOATING_POINT | |
263 # define double sqlite3_int64 | |
264 #endif | |
265 | |
266 /* | |
267 ** CAPI3REF: Closing A Database Connection | |
268 ** | |
269 ** ^The sqlite3_close() routine is the destructor for the [sqlite3] object. | |
270 ** ^Calls to sqlite3_close() return SQLITE_OK if the [sqlite3] object is | |
271 ** successfullly destroyed and all associated resources are deallocated. | |
272 ** | |
273 ** Applications must [sqlite3_finalize | finalize] all [prepared statements] | |
274 ** and [sqlite3_blob_close | close] all [BLOB handles] associated with | |
275 ** the [sqlite3] object prior to attempting to close the object. ^If | |
276 ** sqlite3_close() is called on a [database connection] that still has | |
277 ** outstanding [prepared statements] or [BLOB handles], then it returns | |
278 ** SQLITE_BUSY. | |
279 ** | |
280 ** ^If [sqlite3_close()] is invoked while a transaction is open, | |
281 ** the transaction is automatically rolled back. | |
282 ** | |
283 ** The C parameter to [sqlite3_close(C)] must be either a NULL | |
284 ** pointer or an [sqlite3] object pointer obtained | |
285 ** from [sqlite3_open()], [sqlite3_open16()], or | |
286 ** [sqlite3_open_v2()], and not previously closed. | |
287 ** ^Calling sqlite3_close() with a NULL pointer argument is a | |
288 ** harmless no-op. | |
289 */ | |
290 SQLITE_API int sqlite3_close(sqlite3 *); | |
291 | |
292 /* | |
293 ** The type for a callback function. | |
294 ** This is legacy and deprecated. It is included for historical | |
295 ** compatibility and is not documented. | |
296 */ | |
297 typedef int (*sqlite3_callback)(void*,int,char**, char**); | |
298 | |
299 /* | |
300 ** CAPI3REF: One-Step Query Execution Interface | |
301 ** | |
302 ** The sqlite3_exec() interface is a convenience wrapper around | |
303 ** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], | |
304 ** that allows an application to run multiple statements of SQL | |
305 ** without having to use a lot of C code. | |
306 ** | |
307 ** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, | |
308 ** semicolon-separate SQL statements passed into its 2nd argument, | |
309 ** in the context of the [database connection] passed in as its 1st | |
310 ** argument. ^If the callback function of the 3rd argument to | |
311 ** sqlite3_exec() is not NULL, then it is invoked for each result row | |
312 ** coming out of the evaluated SQL statements. ^The 4th argument to | |
313 ** to sqlite3_exec() is relayed through to the 1st argument of each | |
314 ** callback invocation. ^If the callback pointer to sqlite3_exec() | |
315 ** is NULL, then no callback is ever invoked and result rows are | |
316 ** ignored. | |
317 ** | |
318 ** ^If an error occurs while evaluating the SQL statements passed into | |
319 ** sqlite3_exec(), then execution of the current statement stops and | |
320 ** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() | |
321 ** is not NULL then any error message is written into memory obtained | |
322 ** from [sqlite3_malloc()] and passed back through the 5th parameter. | |
323 ** To avoid memory leaks, the application should invoke [sqlite3_free()] | |
324 ** on error message strings returned through the 5th parameter of | |
325 ** of sqlite3_exec() after the error message string is no longer needed. | |
326 ** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors | |
327 ** occur, then sqlite3_exec() sets the pointer in its 5th parameter to | |
328 ** NULL before returning. | |
329 ** | |
330 ** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() | |
331 ** routine returns SQLITE_ABORT without invoking the callback again and | |
332 ** without running any subsequent SQL statements. | |
333 ** | |
334 ** ^The 2nd argument to the sqlite3_exec() callback function is the | |
335 ** number of columns in the result. ^The 3rd argument to the sqlite3_exec() | |
336 ** callback is an array of pointers to strings obtained as if from | |
337 ** [sqlite3_column_text()], one for each column. ^If an element of a | |
338 ** result row is NULL then the corresponding string pointer for the | |
339 ** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the | |
340 ** sqlite3_exec() callback is an array of pointers to strings where each | |
341 ** entry represents the name of corresponding result column as obtained | |
342 ** from [sqlite3_column_name()]. | |
343 ** | |
344 ** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer | |
345 ** to an empty string, or a pointer that contains only whitespace and/or | |
346 ** SQL comments, then no SQL statements are evaluated and the database | |
347 ** is not changed. | |
348 ** | |
349 ** Restrictions: | |
350 ** | |
351 ** <ul> | |
352 ** <li> The application must insure that the 1st parameter to sqlite3_exec() | |
353 ** is a valid and open [database connection]. | |
354 ** <li> The application must not close [database connection] specified by | |
355 ** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running. | |
356 ** <li> The application must not modify the SQL statement text passed into | |
357 ** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running. | |
358 ** </ul> | |
359 */ | |
360 SQLITE_API int sqlite3_exec( | |
361 sqlite3*, /* An open database */ | |
362 const char *sql, /* SQL to be evaluated */ | |
363 int (*callback)(void*,int,char**,char**), /* Callback function */ | |
364 void *, /* 1st argument to callback */ | |
365 char **errmsg /* Error msg written here */ | |
366 ); | |
367 | |
368 /* | |
369 ** CAPI3REF: Result Codes | |
370 ** KEYWORDS: SQLITE_OK {error code} {error codes} | |
371 ** KEYWORDS: {result code} {result codes} | |
372 ** | |
373 ** Many SQLite functions return an integer result code from the set shown | |
374 ** here in order to indicates success or failure. | |
375 ** | |
376 ** New error codes may be added in future versions of SQLite. | |
377 ** | |
378 ** See also: [SQLITE_IOERR_READ | extended result codes] | |
379 */ | |
380 #define SQLITE_OK 0 /* Successful result */ | |
381 /* beginning-of-error-codes */ | |
382 #define SQLITE_ERROR 1 /* SQL error or missing database */ | |
383 #define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ | |
384 #define SQLITE_PERM 3 /* Access permission denied */ | |
385 #define SQLITE_ABORT 4 /* Callback routine requested an abort */ | |
386 #define SQLITE_BUSY 5 /* The database file is locked */ | |
387 #define SQLITE_LOCKED 6 /* A table in the database is locked */ | |
388 #define SQLITE_NOMEM 7 /* A malloc() failed */ | |
389 #define SQLITE_READONLY 8 /* Attempt to write a readonly database */ | |
390 #define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ | |
391 #define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ | |
392 #define SQLITE_CORRUPT 11 /* The database disk image is malformed */ | |
393 #define SQLITE_NOTFOUND 12 /* NOT USED. Table or record not found */ | |
394 #define SQLITE_FULL 13 /* Insertion failed because database is full */ | |
395 #define SQLITE_CANTOPEN 14 /* Unable to open the database file */ | |
396 #define SQLITE_PROTOCOL 15 /* Database lock protocol error */ | |
397 #define SQLITE_EMPTY 16 /* Database is empty */ | |
398 #define SQLITE_SCHEMA 17 /* The database schema changed */ | |
399 #define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ | |
400 #define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ | |
401 #define SQLITE_MISMATCH 20 /* Data type mismatch */ | |
402 #define SQLITE_MISUSE 21 /* Library used incorrectly */ | |
403 #define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ | |
404 #define SQLITE_AUTH 23 /* Authorization denied */ | |
405 #define SQLITE_FORMAT 24 /* Auxiliary database format error */ | |
406 #define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ | |
407 #define SQLITE_NOTADB 26 /* File opened that is not a database file */ | |
408 #define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ | |
409 #define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ | |
410 /* end-of-error-codes */ | |
411 | |
412 /* | |
413 ** CAPI3REF: Extended Result Codes | |
414 ** KEYWORDS: {extended error code} {extended error codes} | |
415 ** KEYWORDS: {extended result code} {extended result codes} | |
416 ** | |
417 ** In its default configuration, SQLite API routines return one of 26 integer | |
418 ** [SQLITE_OK | result codes]. However, experience has shown that many of | |
419 ** these result codes are too coarse-grained. They do not provide as | |
420 ** much information about problems as programmers might like. In an effort to | |
421 ** address this, newer versions of SQLite (version 3.3.8 and later) include | |
422 ** support for additional result codes that provide more detailed information | |
423 ** about errors. The extended result codes are enabled or disabled | |
424 ** on a per database connection basis using the | |
425 ** [sqlite3_extended_result_codes()] API. | |
426 ** | |
427 ** Some of the available extended result codes are listed here. | |
428 ** One may expect the number of extended result codes will be expand | |
429 ** over time. Software that uses extended result codes should expect | |
430 ** to see new result codes in future releases of SQLite. | |
431 ** | |
432 ** The SQLITE_OK result code will never be extended. It will always | |
433 ** be exactly zero. | |
434 */ | |
435 #define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) | |
436 #define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) | |
437 #define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) | |
438 #define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) | |
439 #define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) | |
440 #define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) | |
441 #define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) | |
442 #define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) | |
443 #define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) | |
444 #define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) | |
445 #define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) | |
446 #define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) | |
447 #define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) | |
448 #define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) | |
449 #define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) | |
450 #define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) | |
451 #define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) | |
452 #define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) | |
453 #define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) | |
454 #define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) | |
455 #define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) | |
456 #define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) | |
457 #define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) | |
458 | |
459 /* | |
460 ** CAPI3REF: Flags For File Open Operations | |
461 ** | |
462 ** These bit values are intended for use in the | |
463 ** 3rd parameter to the [sqlite3_open_v2()] interface and | |
464 ** in the 4th parameter to the xOpen method of the | |
465 ** [sqlite3_vfs] object. | |
466 */ | |
467 #define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ | |
468 #define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ | |
469 #define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ | |
470 #define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ | |
471 #define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ | |
472 #define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ | |
473 #define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ | |
474 #define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ | |
475 #define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ | |
476 #define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ | |
477 #define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ | |
478 #define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ | |
479 #define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ | |
480 #define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ | |
481 #define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ | |
482 #define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ | |
483 #define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ | |
484 #define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ | |
485 | |
486 /* | |
487 ** CAPI3REF: Device Characteristics | |
488 ** | |
489 ** The xDeviceCharacteristics method of the [sqlite3_io_methods] | |
490 ** object returns an integer which is a vector of the these | |
491 ** bit values expressing I/O characteristics of the mass storage | |
492 ** device that holds the file that the [sqlite3_io_methods] | |
493 ** refers to. | |
494 ** | |
495 ** The SQLITE_IOCAP_ATOMIC property means that all writes of | |
496 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values | |
497 ** mean that writes of blocks that are nnn bytes in size and | |
498 ** are aligned to an address which is an integer multiple of | |
499 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means | |
500 ** that when data is appended to a file, the data is appended | |
501 ** first then the size of the file is extended, never the other | |
502 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that | |
503 ** information is written to disk in the same order as calls | |
504 ** to xWrite(). | |
505 */ | |
506 #define SQLITE_IOCAP_ATOMIC 0x00000001 | |
507 #define SQLITE_IOCAP_ATOMIC512 0x00000002 | |
508 #define SQLITE_IOCAP_ATOMIC1K 0x00000004 | |
509 #define SQLITE_IOCAP_ATOMIC2K 0x00000008 | |
510 #define SQLITE_IOCAP_ATOMIC4K 0x00000010 | |
511 #define SQLITE_IOCAP_ATOMIC8K 0x00000020 | |
512 #define SQLITE_IOCAP_ATOMIC16K 0x00000040 | |
513 #define SQLITE_IOCAP_ATOMIC32K 0x00000080 | |
514 #define SQLITE_IOCAP_ATOMIC64K 0x00000100 | |
515 #define SQLITE_IOCAP_SAFE_APPEND 0x00000200 | |
516 #define SQLITE_IOCAP_SEQUENTIAL 0x00000400 | |
517 #define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 | |
518 | |
519 /* | |
520 ** CAPI3REF: File Locking Levels | |
521 ** | |
522 ** SQLite uses one of these integer values as the second | |
523 ** argument to calls it makes to the xLock() and xUnlock() methods | |
524 ** of an [sqlite3_io_methods] object. | |
525 */ | |
526 #define SQLITE_LOCK_NONE 0 | |
527 #define SQLITE_LOCK_SHARED 1 | |
528 #define SQLITE_LOCK_RESERVED 2 | |
529 #define SQLITE_LOCK_PENDING 3 | |
530 #define SQLITE_LOCK_EXCLUSIVE 4 | |
531 | |
532 /* | |
533 ** CAPI3REF: Synchronization Type Flags | |
534 ** | |
535 ** When SQLite invokes the xSync() method of an | |
536 ** [sqlite3_io_methods] object it uses a combination of | |
537 ** these integer values as the second argument. | |
538 ** | |
539 ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the | |
540 ** sync operation only needs to flush data to mass storage. Inode | |
541 ** information need not be flushed. If the lower four bits of the flag | |
542 ** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. | |
543 ** If the lower four bits equal SQLITE_SYNC_FULL, that means | |
544 ** to use Mac OS X style fullsync instead of fsync(). | |
545 */ | |
546 #define SQLITE_SYNC_NORMAL 0x00002 | |
547 #define SQLITE_SYNC_FULL 0x00003 | |
548 #define SQLITE_SYNC_DATAONLY 0x00010 | |
549 | |
550 /* | |
551 ** CAPI3REF: OS Interface Open File Handle | |
552 ** | |
553 ** An [sqlite3_file] object represents an open file in the | |
554 ** [sqlite3_vfs | OS interface layer]. Individual OS interface | |
555 ** implementations will | |
556 ** want to subclass this object by appending additional fields | |
557 ** for their own use. The pMethods entry is a pointer to an | |
558 ** [sqlite3_io_methods] object that defines methods for performing | |
559 ** I/O operations on the open file. | |
560 */ | |
561 typedef struct sqlite3_file sqlite3_file; | |
562 struct sqlite3_file { | |
563 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ | |
564 }; | |
565 | |
566 /* | |
567 ** CAPI3REF: OS Interface File Virtual Methods Object | |
568 ** | |
569 ** Every file opened by the [sqlite3_vfs] xOpen method populates an | |
570 ** [sqlite3_file] object (or, more commonly, a subclass of the | |
571 ** [sqlite3_file] object) with a pointer to an instance of this object. | |
572 ** This object defines the methods used to perform various operations | |
573 ** against the open file represented by the [sqlite3_file] object. | |
574 ** | |
575 ** If the xOpen method sets the sqlite3_file.pMethods element | |
576 ** to a non-NULL pointer, then the sqlite3_io_methods.xClose method | |
577 ** may be invoked even if the xOpen reported that it failed. The | |
578 ** only way to prevent a call to xClose following a failed xOpen | |
579 ** is for the xOpen to set the sqlite3_file.pMethods element to NULL. | |
580 ** | |
581 ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or | |
582 ** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). | |
583 ** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] | |
584 ** flag may be ORed in to indicate that only the data of the file | |
585 ** and not its inode needs to be synced. | |
586 ** | |
587 ** The integer values to xLock() and xUnlock() are one of | |
588 ** <ul> | |
589 ** <li> [SQLITE_LOCK_NONE], | |
590 ** <li> [SQLITE_LOCK_SHARED], | |
591 ** <li> [SQLITE_LOCK_RESERVED], | |
592 ** <li> [SQLITE_LOCK_PENDING], or | |
593 ** <li> [SQLITE_LOCK_EXCLUSIVE]. | |
594 ** </ul> | |
595 ** xLock() increases the lock. xUnlock() decreases the lock. | |
596 ** The xCheckReservedLock() method checks whether any database connection, | |
597 ** either in this process or in some other process, is holding a RESERVED, | |
598 ** PENDING, or EXCLUSIVE lock on the file. It returns true | |
599 ** if such a lock exists and false otherwise. | |
600 ** | |
601 ** The xFileControl() method is a generic interface that allows custom | |
602 ** VFS implementations to directly control an open file using the | |
603 ** [sqlite3_file_control()] interface. The second "op" argument is an | |
604 ** integer opcode. The third argument is a generic pointer intended to | |
605 ** point to a structure that may contain arguments or space in which to | |
606 ** write return values. Potential uses for xFileControl() might be | |
607 ** functions to enable blocking locks with timeouts, to change the | |
608 ** locking strategy (for example to use dot-file locks), to inquire | |
609 ** about the status of a lock, or to break stale locks. The SQLite | |
610 ** core reserves all opcodes less than 100 for its own use. | |
611 ** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available. | |
612 ** Applications that define a custom xFileControl method should use opcodes | |
613 ** greater than 100 to avoid conflicts. | |
614 ** | |
615 ** The xSectorSize() method returns the sector size of the | |
616 ** device that underlies the file. The sector size is the | |
617 ** minimum write that can be performed without disturbing | |
618 ** other bytes in the file. The xDeviceCharacteristics() | |
619 ** method returns a bit vector describing behaviors of the | |
620 ** underlying device: | |
621 ** | |
622 ** <ul> | |
623 ** <li> [SQLITE_IOCAP_ATOMIC] | |
624 ** <li> [SQLITE_IOCAP_ATOMIC512] | |
625 ** <li> [SQLITE_IOCAP_ATOMIC1K] | |
626 ** <li> [SQLITE_IOCAP_ATOMIC2K] | |
627 ** <li> [SQLITE_IOCAP_ATOMIC4K] | |
628 ** <li> [SQLITE_IOCAP_ATOMIC8K] | |
629 ** <li> [SQLITE_IOCAP_ATOMIC16K] | |
630 ** <li> [SQLITE_IOCAP_ATOMIC32K] | |
631 ** <li> [SQLITE_IOCAP_ATOMIC64K] | |
632 ** <li> [SQLITE_IOCAP_SAFE_APPEND] | |
633 ** <li> [SQLITE_IOCAP_SEQUENTIAL] | |
634 ** </ul> | |
635 ** | |
636 ** The SQLITE_IOCAP_ATOMIC property means that all writes of | |
637 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values | |
638 ** mean that writes of blocks that are nnn bytes in size and | |
639 ** are aligned to an address which is an integer multiple of | |
640 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means | |
641 ** that when data is appended to a file, the data is appended | |
642 ** first then the size of the file is extended, never the other | |
643 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that | |
644 ** information is written to disk in the same order as calls | |
645 ** to xWrite(). | |
646 ** | |
647 ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill | |
648 ** in the unread portions of the buffer with zeros. A VFS that | |
649 ** fails to zero-fill short reads might seem to work. However, | |
650 ** failure to zero-fill short reads will eventually lead to | |
651 ** database corruption. | |
652 */ | |
653 typedef struct sqlite3_io_methods sqlite3_io_methods; | |
654 struct sqlite3_io_methods { | |
655 int iVersion; | |
656 int (*xClose)(sqlite3_file*); | |
657 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); | |
658 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); | |
659 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); | |
660 int (*xSync)(sqlite3_file*, int flags); | |
661 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); | |
662 int (*xLock)(sqlite3_file*, int); | |
663 int (*xUnlock)(sqlite3_file*, int); | |
664 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); | |
665 int (*xFileControl)(sqlite3_file*, int op, void *pArg); | |
666 int (*xSectorSize)(sqlite3_file*); | |
667 int (*xDeviceCharacteristics)(sqlite3_file*); | |
668 /* Methods above are valid for version 1 */ | |
669 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); | |
670 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); | |
671 void (*xShmBarrier)(sqlite3_file*); | |
672 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); | |
673 /* Methods above are valid for version 2 */ | |
674 /* Additional methods may be added in future releases */ | |
675 }; | |
676 | |
677 /* | |
678 ** CAPI3REF: Standard File Control Opcodes | |
679 ** | |
680 ** These integer constants are opcodes for the xFileControl method | |
681 ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] | |
682 ** interface. | |
683 ** | |
684 ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This | |
685 ** opcode causes the xFileControl method to write the current state of | |
686 ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], | |
687 ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) | |
688 ** into an integer that the pArg argument points to. This capability | |
689 ** is used during testing and only needs to be supported when SQLITE_TEST | |
690 ** is defined. | |
691 ** | |
692 ** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS | |
693 ** layer a hint of how large the database file will grow to be during the | |
694 ** current transaction. This hint is not guaranteed to be accurate but it | |
695 ** is often close. The underlying VFS might choose to preallocate database | |
696 ** file space based on this hint in order to help writes to the database | |
697 ** file run faster. | |
698 */ | |
699 #define SQLITE_FCNTL_LOCKSTATE 1 | |
700 #define SQLITE_GET_LOCKPROXYFILE 2 | |
701 #define SQLITE_SET_LOCKPROXYFILE 3 | |
702 #define SQLITE_LAST_ERRNO 4 | |
703 #define SQLITE_FCNTL_SIZE_HINT 5 | |
704 | |
705 /* | |
706 ** CAPI3REF: Mutex Handle | |
707 ** | |
708 ** The mutex module within SQLite defines [sqlite3_mutex] to be an | |
709 ** abstract type for a mutex object. The SQLite core never looks | |
710 ** at the internal representation of an [sqlite3_mutex]. It only | |
711 ** deals with pointers to the [sqlite3_mutex] object. | |
712 ** | |
713 ** Mutexes are created using [sqlite3_mutex_alloc()]. | |
714 */ | |
715 typedef struct sqlite3_mutex sqlite3_mutex; | |
716 | |
717 /* | |
718 ** CAPI3REF: OS Interface Object | |
719 ** | |
720 ** An instance of the sqlite3_vfs object defines the interface between | |
721 ** the SQLite core and the underlying operating system. The "vfs" | |
722 ** in the name of the object stands for "virtual file system". | |
723 ** | |
724 ** The value of the iVersion field is initially 1 but may be larger in | |
725 ** future versions of SQLite. Additional fields may be appended to this | |
726 ** object when the iVersion value is increased. Note that the structure | |
727 ** of the sqlite3_vfs object changes in the transaction between | |
728 ** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not | |
729 ** modified. | |
730 ** | |
731 ** The szOsFile field is the size of the subclassed [sqlite3_file] | |
732 ** structure used by this VFS. mxPathname is the maximum length of | |
733 ** a pathname in this VFS. | |
734 ** | |
735 ** Registered sqlite3_vfs objects are kept on a linked list formed by | |
736 ** the pNext pointer. The [sqlite3_vfs_register()] | |
737 ** and [sqlite3_vfs_unregister()] interfaces manage this list | |
738 ** in a thread-safe way. The [sqlite3_vfs_find()] interface | |
739 ** searches the list. Neither the application code nor the VFS | |
740 ** implementation should use the pNext pointer. | |
741 ** | |
742 ** The pNext field is the only field in the sqlite3_vfs | |
743 ** structure that SQLite will ever modify. SQLite will only access | |
744 ** or modify this field while holding a particular static mutex. | |
745 ** The application should never modify anything within the sqlite3_vfs | |
746 ** object once the object has been registered. | |
747 ** | |
748 ** The zName field holds the name of the VFS module. The name must | |
749 ** be unique across all VFS modules. | |
750 ** | |
751 ** SQLite will guarantee that the zFilename parameter to xOpen | |
752 ** is either a NULL pointer or string obtained | |
753 ** from xFullPathname(). SQLite further guarantees that | |
754 ** the string will be valid and unchanged until xClose() is | |
755 ** called. Because of the previous sentence, | |
756 ** the [sqlite3_file] can safely store a pointer to the | |
757 ** filename if it needs to remember the filename for some reason. | |
758 ** If the zFilename parameter is xOpen is a NULL pointer then xOpen | |
759 ** must invent its own temporary name for the file. Whenever the | |
760 ** xFilename parameter is NULL it will also be the case that the | |
761 ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. | |
762 ** | |
763 ** The flags argument to xOpen() includes all bits set in | |
764 ** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] | |
765 ** or [sqlite3_open16()] is used, then flags includes at least | |
766 ** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. | |
767 ** If xOpen() opens a file read-only then it sets *pOutFlags to | |
768 ** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. | |
769 ** | |
770 ** SQLite will also add one of the following flags to the xOpen() | |
771 ** call, depending on the object being opened: | |
772 ** | |
773 ** <ul> | |
774 ** <li> [SQLITE_OPEN_MAIN_DB] | |
775 ** <li> [SQLITE_OPEN_MAIN_JOURNAL] | |
776 ** <li> [SQLITE_OPEN_TEMP_DB] | |
777 ** <li> [SQLITE_OPEN_TEMP_JOURNAL] | |
778 ** <li> [SQLITE_OPEN_TRANSIENT_DB] | |
779 ** <li> [SQLITE_OPEN_SUBJOURNAL] | |
780 ** <li> [SQLITE_OPEN_MASTER_JOURNAL] | |
781 ** </ul> | |
782 ** | |
783 ** The file I/O implementation can use the object type flags to | |
784 ** change the way it deals with files. For example, an application | |
785 ** that does not care about crash recovery or rollback might make | |
786 ** the open of a journal file a no-op. Writes to this journal would | |
787 ** also be no-ops, and any attempt to read the journal would return | |
788 ** SQLITE_IOERR. Or the implementation might recognize that a database | |
789 ** file will be doing page-aligned sector reads and writes in a random | |
790 ** order and set up its I/O subsystem accordingly. | |
791 ** | |
792 ** SQLite might also add one of the following flags to the xOpen method: | |
793 ** | |
794 ** <ul> | |
795 ** <li> [SQLITE_OPEN_DELETEONCLOSE] | |
796 ** <li> [SQLITE_OPEN_EXCLUSIVE] | |
797 ** </ul> | |
798 ** | |
799 ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be | |
800 ** deleted when it is closed. The [SQLITE_OPEN_DELETEONCLOSE] | |
801 ** will be set for TEMP databases, journals and for subjournals. | |
802 ** | |
803 ** The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction | |
804 ** with the [SQLITE_OPEN_CREATE] flag, which are both directly | |
805 ** analogous to the O_EXCL and O_CREAT flags of the POSIX open() | |
806 ** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the | |
807 ** SQLITE_OPEN_CREATE, is used to indicate that file should always | |
808 ** be created, and that it is an error if it already exists. | |
809 ** It is <i>not</i> used to indicate the file should be opened | |
810 ** for exclusive access. | |
811 ** | |
812 ** At least szOsFile bytes of memory are allocated by SQLite | |
813 ** to hold the [sqlite3_file] structure passed as the third | |
814 ** argument to xOpen. The xOpen method does not have to | |
815 ** allocate the structure; it should just fill it in. Note that | |
816 ** the xOpen method must set the sqlite3_file.pMethods to either | |
817 ** a valid [sqlite3_io_methods] object or to NULL. xOpen must do | |
818 ** this even if the open fails. SQLite expects that the sqlite3_file.pMethods | |
819 ** element will be valid after xOpen returns regardless of the success | |
820 ** or failure of the xOpen call. | |
821 ** | |
822 ** The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] | |
823 ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to | |
824 ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] | |
825 ** to test whether a file is at least readable. The file can be a | |
826 ** directory. | |
827 ** | |
828 ** SQLite will always allocate at least mxPathname+1 bytes for the | |
829 ** output buffer xFullPathname. The exact size of the output buffer | |
830 ** is also passed as a parameter to both methods. If the output buffer | |
831 ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is | |
832 ** handled as a fatal error by SQLite, vfs implementations should endeavor | |
833 ** to prevent this by setting mxPathname to a sufficiently large value. | |
834 ** | |
835 ** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() | |
836 ** interfaces are not strictly a part of the filesystem, but they are | |
837 ** included in the VFS structure for completeness. | |
838 ** The xRandomness() function attempts to return nBytes bytes | |
839 ** of good-quality randomness into zOut. The return value is | |
840 ** the actual number of bytes of randomness obtained. | |
841 ** The xSleep() method causes the calling thread to sleep for at | |
842 ** least the number of microseconds given. The xCurrentTime() | |
843 ** method returns a Julian Day Number for the current date and time as | |
844 ** a floating point value. | |
845 ** The xCurrentTimeInt64() method returns, as an integer, the Julian | |
846 ** Day Number multipled by 86400000 (the number of milliseconds in | |
847 ** a 24-hour day). | |
848 ** ^SQLite will use the xCurrentTimeInt64() method to get the current | |
849 ** date and time if that method is available (if iVersion is 2 or | |
850 ** greater and the function pointer is not NULL) and will fall back | |
851 ** to xCurrentTime() if xCurrentTimeInt64() is unavailable. | |
852 */ | |
853 typedef struct sqlite3_vfs sqlite3_vfs; | |
854 struct sqlite3_vfs { | |
855 int iVersion; /* Structure version number (currently 2) */ | |
856 int szOsFile; /* Size of subclassed sqlite3_file */ | |
857 int mxPathname; /* Maximum file pathname length */ | |
858 sqlite3_vfs *pNext; /* Next registered VFS */ | |
859 const char *zName; /* Name of this virtual file system */ | |
860 void *pAppData; /* Pointer to application-specific data */ | |
861 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, | |
862 int flags, int *pOutFlags); | |
863 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); | |
864 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); | |
865 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); | |
866 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); | |
867 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); | |
868 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); | |
869 void (*xDlClose)(sqlite3_vfs*, void*); | |
870 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); | |
871 int (*xSleep)(sqlite3_vfs*, int microseconds); | |
872 int (*xCurrentTime)(sqlite3_vfs*, double*); | |
873 int (*xGetLastError)(sqlite3_vfs*, int, char *); | |
874 /* | |
875 ** The methods above are in version 1 of the sqlite_vfs object | |
876 ** definition. Those that follow are added in version 2 or later | |
877 */ | |
878 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); | |
879 /* | |
880 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. | |
881 ** New fields may be appended in figure versions. The iVersion | |
882 ** value will increment whenever this happens. | |
883 */ | |
884 }; | |
885 | |
886 /* | |
887 ** CAPI3REF: Flags for the xAccess VFS method | |
888 ** | |
889 ** These integer constants can be used as the third parameter to | |
890 ** the xAccess method of an [sqlite3_vfs] object. They determine | |
891 ** what kind of permissions the xAccess method is looking for. | |
892 ** With SQLITE_ACCESS_EXISTS, the xAccess method | |
893 ** simply checks whether the file exists. | |
894 ** With SQLITE_ACCESS_READWRITE, the xAccess method | |
895 ** checks whether the named directory is both readable and writable | |
896 ** (in other words, if files can be added, removed, and renamed within | |
897 ** the directory). | |
898 ** The SQLITE_ACCESS_READWRITE constant is currently used only by the | |
899 ** [temp_store_directory pragma], though this could change in a future | |
900 ** release of SQLite. | |
901 ** With SQLITE_ACCESS_READ, the xAccess method | |
902 ** checks whether the file is readable. The SQLITE_ACCESS_READ constant is | |
903 ** currently unused, though it might be used in a future release of | |
904 ** SQLite. | |
905 */ | |
906 #define SQLITE_ACCESS_EXISTS 0 | |
907 #define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ | |
908 #define SQLITE_ACCESS_READ 2 /* Unused */ | |
909 | |
910 /* | |
911 ** CAPI3REF: Flags for the xShmLock VFS method | |
912 ** | |
913 ** These integer constants define the various locking operations | |
914 ** allowed by the xShmLock method of [sqlite3_io_methods]. The | |
915 ** following are the only legal combinations of flags to the | |
916 ** xShmLock method: | |
917 ** | |
918 ** <ul> | |
919 ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED | |
920 ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE | |
921 ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED | |
922 ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE | |
923 ** </ul> | |
924 ** | |
925 ** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as | |
926 ** was given no the corresponding lock. | |
927 ** | |
928 ** The xShmLock method can transition between unlocked and SHARED or | |
929 ** between unlocked and EXCLUSIVE. It cannot transition between SHARED | |
930 ** and EXCLUSIVE. | |
931 */ | |
932 #define SQLITE_SHM_UNLOCK 1 | |
933 #define SQLITE_SHM_LOCK 2 | |
934 #define SQLITE_SHM_SHARED 4 | |
935 #define SQLITE_SHM_EXCLUSIVE 8 | |
936 | |
937 /* | |
938 ** CAPI3REF: Maximum xShmLock index | |
939 ** | |
940 ** The xShmLock method on [sqlite3_io_methods] may use values | |
941 ** between 0 and this upper bound as its "offset" argument. | |
942 ** The SQLite core will never attempt to acquire or release a | |
943 ** lock outside of this range | |
944 */ | |
945 #define SQLITE_SHM_NLOCK 8 | |
946 | |
947 | |
948 /* | |
949 ** CAPI3REF: Initialize The SQLite Library | |
950 ** | |
951 ** ^The sqlite3_initialize() routine initializes the | |
952 ** SQLite library. ^The sqlite3_shutdown() routine | |
953 ** deallocates any resources that were allocated by sqlite3_initialize(). | |
954 ** These routines are designed to aid in process initialization and | |
955 ** shutdown on embedded systems. Workstation applications using | |
956 ** SQLite normally do not need to invoke either of these routines. | |
957 ** | |
958 ** A call to sqlite3_initialize() is an "effective" call if it is | |
959 ** the first time sqlite3_initialize() is invoked during the lifetime of | |
960 ** the process, or if it is the first time sqlite3_initialize() is invoked | |
961 ** following a call to sqlite3_shutdown(). ^(Only an effective call | |
962 ** of sqlite3_initialize() does any initialization. All other calls | |
963 ** are harmless no-ops.)^ | |
964 ** | |
965 ** A call to sqlite3_shutdown() is an "effective" call if it is the first | |
966 ** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only | |
967 ** an effective call to sqlite3_shutdown() does any deinitialization. | |
968 ** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ | |
969 ** | |
970 ** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() | |
971 ** is not. The sqlite3_shutdown() interface must only be called from a | |
972 ** single thread. All open [database connections] must be closed and all | |
973 ** other SQLite resources must be deallocated prior to invoking | |
974 ** sqlite3_shutdown(). | |
975 ** | |
976 ** Among other things, ^sqlite3_initialize() will invoke | |
977 ** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() | |
978 ** will invoke sqlite3_os_end(). | |
979 ** | |
980 ** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. | |
981 ** ^If for some reason, sqlite3_initialize() is unable to initialize | |
982 ** the library (perhaps it is unable to allocate a needed resource such | |
983 ** as a mutex) it returns an [error code] other than [SQLITE_OK]. | |
984 ** | |
985 ** ^The sqlite3_initialize() routine is called internally by many other | |
986 ** SQLite interfaces so that an application usually does not need to | |
987 ** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] | |
988 ** calls sqlite3_initialize() so the SQLite library will be automatically | |
989 ** initialized when [sqlite3_open()] is called if it has not be initialized | |
990 ** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] | |
991 ** compile-time option, then the automatic calls to sqlite3_initialize() | |
992 ** are omitted and the application must call sqlite3_initialize() directly | |
993 ** prior to using any other SQLite interface. For maximum portability, | |
994 ** it is recommended that applications always invoke sqlite3_initialize() | |
995 ** directly prior to using any other SQLite interface. Future releases | |
996 ** of SQLite may require this. In other words, the behavior exhibited | |
997 ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the | |
998 ** default behavior in some future release of SQLite. | |
999 ** | |
1000 ** The sqlite3_os_init() routine does operating-system specific | |
1001 ** initialization of the SQLite library. The sqlite3_os_end() | |
1002 ** routine undoes the effect of sqlite3_os_init(). Typical tasks | |
1003 ** performed by these routines include allocation or deallocation | |
1004 ** of static resources, initialization of global variables, | |
1005 ** setting up a default [sqlite3_vfs] module, or setting up | |
1006 ** a default configuration using [sqlite3_config()]. | |
1007 ** | |
1008 ** The application should never invoke either sqlite3_os_init() | |
1009 ** or sqlite3_os_end() directly. The application should only invoke | |
1010 ** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() | |
1011 ** interface is called automatically by sqlite3_initialize() and | |
1012 ** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate | |
1013 ** implementations for sqlite3_os_init() and sqlite3_os_end() | |
1014 ** are built into SQLite when it is compiled for Unix, Windows, or OS/2. | |
1015 ** When [custom builds | built for other platforms] | |
1016 ** (using the [SQLITE_OS_OTHER=1] compile-time | |
1017 ** option) the application must supply a suitable implementation for | |
1018 ** sqlite3_os_init() and sqlite3_os_end(). An application-supplied | |
1019 ** implementation of sqlite3_os_init() or sqlite3_os_end() | |
1020 ** must return [SQLITE_OK] on success and some other [error code] upon | |
1021 ** failure. | |
1022 */ | |
1023 SQLITE_API int sqlite3_initialize(void); | |
1024 SQLITE_API int sqlite3_shutdown(void); | |
1025 SQLITE_API int sqlite3_os_init(void); | |
1026 SQLITE_API int sqlite3_os_end(void); | |
1027 | |
1028 /* | |
1029 ** CAPI3REF: Configuring The SQLite Library | |
1030 ** | |
1031 ** The sqlite3_config() interface is used to make global configuration | |
1032 ** changes to SQLite in order to tune SQLite to the specific needs of | |
1033 ** the application. The default configuration is recommended for most | |
1034 ** applications and so this routine is usually not necessary. It is | |
1035 ** provided to support rare applications with unusual needs. | |
1036 ** | |
1037 ** The sqlite3_config() interface is not threadsafe. The application | |
1038 ** must insure that no other SQLite interfaces are invoked by other | |
1039 ** threads while sqlite3_config() is running. Furthermore, sqlite3_config() | |
1040 ** may only be invoked prior to library initialization using | |
1041 ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. | |
1042 ** ^If sqlite3_config() is called after [sqlite3_initialize()] and before | |
1043 ** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. | |
1044 ** Note, however, that ^sqlite3_config() can be called as part of the | |
1045 ** implementation of an application-defined [sqlite3_os_init()]. | |
1046 ** | |
1047 ** The first argument to sqlite3_config() is an integer | |
1048 ** [SQLITE_CONFIG_SINGLETHREAD | configuration option] that determines | |
1049 ** what property of SQLite is to be configured. Subsequent arguments | |
1050 ** vary depending on the [SQLITE_CONFIG_SINGLETHREAD | configuration option] | |
1051 ** in the first argument. | |
1052 ** | |
1053 ** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. | |
1054 ** ^If the option is unknown or SQLite is unable to set the option | |
1055 ** then this routine returns a non-zero [error code]. | |
1056 */ | |
1057 SQLITE_API int sqlite3_config(int, ...); | |
1058 | |
1059 /* | |
1060 ** CAPI3REF: Configure database connections | |
1061 ** | |
1062 ** The sqlite3_db_config() interface is used to make configuration | |
1063 ** changes to a [database connection]. The interface is similar to | |
1064 ** [sqlite3_config()] except that the changes apply to a single | |
1065 ** [database connection] (specified in the first argument). The | |
1066 ** sqlite3_db_config() interface should only be used immediately after | |
1067 ** the database connection is created using [sqlite3_open()], | |
1068 ** [sqlite3_open16()], or [sqlite3_open_v2()]. | |
1069 ** | |
1070 ** The second argument to sqlite3_db_config(D,V,...) is the | |
1071 ** configuration verb - an integer code that indicates what | |
1072 ** aspect of the [database connection] is being configured. | |
1073 ** The only choice for this value is [SQLITE_DBCONFIG_LOOKASIDE]. | |
1074 ** New verbs are likely to be added in future releases of SQLite. | |
1075 ** Additional arguments depend on the verb. | |
1076 ** | |
1077 ** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if | |
1078 ** the call is considered successful. | |
1079 */ | |
1080 SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...); | |
1081 | |
1082 /* | |
1083 ** CAPI3REF: Memory Allocation Routines | |
1084 ** | |
1085 ** An instance of this object defines the interface between SQLite | |
1086 ** and low-level memory allocation routines. | |
1087 ** | |
1088 ** This object is used in only one place in the SQLite interface. | |
1089 ** A pointer to an instance of this object is the argument to | |
1090 ** [sqlite3_config()] when the configuration option is | |
1091 ** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. | |
1092 ** By creating an instance of this object | |
1093 ** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) | |
1094 ** during configuration, an application can specify an alternative | |
1095 ** memory allocation subsystem for SQLite to use for all of its | |
1096 ** dynamic memory needs. | |
1097 ** | |
1098 ** Note that SQLite comes with several [built-in memory allocators] | |
1099 ** that are perfectly adequate for the overwhelming majority of applications | |
1100 ** and that this object is only useful to a tiny minority of applications | |
1101 ** with specialized memory allocation requirements. This object is | |
1102 ** also used during testing of SQLite in order to specify an alternative | |
1103 ** memory allocator that simulates memory out-of-memory conditions in | |
1104 ** order to verify that SQLite recovers gracefully from such | |
1105 ** conditions. | |
1106 ** | |
1107 ** The xMalloc and xFree methods must work like the | |
1108 ** malloc() and free() functions from the standard C library. | |
1109 ** The xRealloc method must work like realloc() from the standard C library | |
1110 ** with the exception that if the second argument to xRealloc is zero, | |
1111 ** xRealloc must be a no-op - it must not perform any allocation or | |
1112 ** deallocation. ^SQLite guarantees that the second argument to | |
1113 ** xRealloc is always a value returned by a prior call to xRoundup. | |
1114 ** And so in cases where xRoundup always returns a positive number, | |
1115 ** xRealloc can perform exactly as the standard library realloc() and | |
1116 ** still be in compliance with this specification. | |
1117 ** | |
1118 ** xSize should return the allocated size of a memory allocation | |
1119 ** previously obtained from xMalloc or xRealloc. The allocated size | |
1120 ** is always at least as big as the requested size but may be larger. | |
1121 ** | |
1122 ** The xRoundup method returns what would be the allocated size of | |
1123 ** a memory allocation given a particular requested size. Most memory | |
1124 ** allocators round up memory allocations at least to the next multiple | |
1125 ** of 8. Some allocators round up to a larger multiple or to a power of 2. | |
1126 ** Every memory allocation request coming in through [sqlite3_malloc()] | |
1127 ** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, | |
1128 ** that causes the corresponding memory allocation to fail. | |
1129 ** | |
1130 ** The xInit method initializes the memory allocator. (For example, | |
1131 ** it might allocate any require mutexes or initialize internal data | |
1132 ** structures. The xShutdown method is invoked (indirectly) by | |
1133 ** [sqlite3_shutdown()] and should deallocate any resources acquired | |
1134 ** by xInit. The pAppData pointer is used as the only parameter to | |
1135 ** xInit and xShutdown. | |
1136 ** | |
1137 ** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes | |
1138 ** the xInit method, so the xInit method need not be threadsafe. The | |
1139 ** xShutdown method is only called from [sqlite3_shutdown()] so it does | |
1140 ** not need to be threadsafe either. For all other methods, SQLite | |
1141 ** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the | |
1142 ** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which | |
1143 ** it is by default) and so the methods are automatically serialized. | |
1144 ** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other | |
1145 ** methods must be threadsafe or else make their own arrangements for | |
1146 ** serialization. | |
1147 ** | |
1148 ** SQLite will never invoke xInit() more than once without an intervening | |
1149 ** call to xShutdown(). | |
1150 */ | |
1151 typedef struct sqlite3_mem_methods sqlite3_mem_methods; | |
1152 struct sqlite3_mem_methods { | |
1153 void *(*xMalloc)(int); /* Memory allocation function */ | |
1154 void (*xFree)(void*); /* Free a prior allocation */ | |
1155 void *(*xRealloc)(void*,int); /* Resize an allocation */ | |
1156 int (*xSize)(void*); /* Return the size of an allocation */ | |
1157 int (*xRoundup)(int); /* Round up request size to allocation size */ | |
1158 int (*xInit)(void*); /* Initialize the memory allocator */ | |
1159 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ | |
1160 void *pAppData; /* Argument to xInit() and xShutdown() */ | |
1161 }; | |
1162 | |
1163 /* | |
1164 ** CAPI3REF: Configuration Options | |
1165 ** | |
1166 ** These constants are the available integer configuration options that | |
1167 ** can be passed as the first argument to the [sqlite3_config()] interface. | |
1168 ** | |
1169 ** New configuration options may be added in future releases of SQLite. | |
1170 ** Existing configuration options might be discontinued. Applications | |
1171 ** should check the return code from [sqlite3_config()] to make sure that | |
1172 ** the call worked. The [sqlite3_config()] interface will return a | |
1173 ** non-zero [error code] if a discontinued or unsupported configuration option | |
1174 ** is invoked. | |
1175 ** | |
1176 ** <dl> | |
1177 ** <dt>SQLITE_CONFIG_SINGLETHREAD</dt> | |
1178 ** <dd>There are no arguments to this option. ^This option sets the | |
1179 ** [threading mode] to Single-thread. In other words, it disables | |
1180 ** all mutexing and puts SQLite into a mode where it can only be used | |
1181 ** by a single thread. ^If SQLite is compiled with | |
1182 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then | |
1183 ** it is not possible to change the [threading mode] from its default | |
1184 ** value of Single-thread and so [sqlite3_config()] will return | |
1185 ** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD | |
1186 ** configuration option.</dd> | |
1187 ** | |
1188 ** <dt>SQLITE_CONFIG_MULTITHREAD</dt> | |
1189 ** <dd>There are no arguments to this option. ^This option sets the | |
1190 ** [threading mode] to Multi-thread. In other words, it disables | |
1191 ** mutexing on [database connection] and [prepared statement] objects. | |
1192 ** The application is responsible for serializing access to | |
1193 ** [database connections] and [prepared statements]. But other mutexes | |
1194 ** are enabled so that SQLite will be safe to use in a multi-threaded | |
1195 ** environment as long as no two threads attempt to use the same | |
1196 ** [database connection] at the same time. ^If SQLite is compiled with | |
1197 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then | |
1198 ** it is not possible to set the Multi-thread [threading mode] and | |
1199 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the | |
1200 ** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> | |
1201 ** | |
1202 ** <dt>SQLITE_CONFIG_SERIALIZED</dt> | |
1203 ** <dd>There are no arguments to this option. ^This option sets the | |
1204 ** [threading mode] to Serialized. In other words, this option enables | |
1205 ** all mutexes including the recursive | |
1206 ** mutexes on [database connection] and [prepared statement] objects. | |
1207 ** In this mode (which is the default when SQLite is compiled with | |
1208 ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access | |
1209 ** to [database connections] and [prepared statements] so that the | |
1210 ** application is free to use the same [database connection] or the | |
1211 ** same [prepared statement] in different threads at the same time. | |
1212 ** ^If SQLite is compiled with | |
1213 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then | |
1214 ** it is not possible to set the Serialized [threading mode] and | |
1215 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the | |
1216 ** SQLITE_CONFIG_SERIALIZED configuration option.</dd> | |
1217 ** | |
1218 ** <dt>SQLITE_CONFIG_MALLOC</dt> | |
1219 ** <dd> ^(This option takes a single argument which is a pointer to an | |
1220 ** instance of the [sqlite3_mem_methods] structure. The argument specifies | |
1221 ** alternative low-level memory allocation routines to be used in place of | |
1222 ** the memory allocation routines built into SQLite.)^ ^SQLite makes | |
1223 ** its own private copy of the content of the [sqlite3_mem_methods] structure | |
1224 ** before the [sqlite3_config()] call returns.</dd> | |
1225 ** | |
1226 ** <dt>SQLITE_CONFIG_GETMALLOC</dt> | |
1227 ** <dd> ^(This option takes a single argument which is a pointer to an | |
1228 ** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods] | |
1229 ** structure is filled with the currently defined memory allocation routines.)^ | |
1230 ** This option can be used to overload the default memory allocation | |
1231 ** routines with a wrapper that simulations memory allocation failure or | |
1232 ** tracks memory usage, for example. </dd> | |
1233 ** | |
1234 ** <dt>SQLITE_CONFIG_MEMSTATUS</dt> | |
1235 ** <dd> ^This option takes single argument of type int, interpreted as a | |
1236 ** boolean, which enables or disables the collection of memory allocation | |
1237 ** statistics. ^(When memory allocation statistics are disabled, the | |
1238 ** following SQLite interfaces become non-operational: | |
1239 ** <ul> | |
1240 ** <li> [sqlite3_memory_used()] | |
1241 ** <li> [sqlite3_memory_highwater()] | |
1242 ** <li> [sqlite3_soft_heap_limit()] | |
1243 ** <li> [sqlite3_status()] | |
1244 ** </ul>)^ | |
1245 ** ^Memory allocation statistics are enabled by default unless SQLite is | |
1246 ** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory | |
1247 ** allocation statistics are disabled by default. | |
1248 ** </dd> | |
1249 ** | |
1250 ** <dt>SQLITE_CONFIG_SCRATCH</dt> | |
1251 ** <dd> ^This option specifies a static memory buffer that SQLite can use for | |
1252 ** scratch memory. There are three arguments: A pointer an 8-byte | |
1253 ** aligned memory buffer from which the scrach allocations will be | |
1254 ** drawn, the size of each scratch allocation (sz), | |
1255 ** and the maximum number of scratch allocations (N). The sz | |
1256 ** argument must be a multiple of 16. The sz parameter should be a few bytes | |
1257 ** larger than the actual scratch space required due to internal overhead. | |
1258 ** The first argument must be a pointer to an 8-byte aligned buffer | |
1259 ** of at least sz*N bytes of memory. | |
1260 ** ^SQLite will use no more than one scratch buffer per thread. So | |
1261 ** N should be set to the expected maximum number of threads. ^SQLite will | |
1262 ** never require a scratch buffer that is more than 6 times the database | |
1263 ** page size. ^If SQLite needs needs additional scratch memory beyond | |
1264 ** what is provided by this configuration option, then | |
1265 ** [sqlite3_malloc()] will be used to obtain the memory needed.</dd> | |
1266 ** | |
1267 ** <dt>SQLITE_CONFIG_PAGECACHE</dt> | |
1268 ** <dd> ^This option specifies a static memory buffer that SQLite can use for | |
1269 ** the database page cache with the default page cache implemenation. | |
1270 ** This configuration should not be used if an application-define page | |
1271 ** cache implementation is loaded using the SQLITE_CONFIG_PCACHE option. | |
1272 ** There are three arguments to this option: A pointer to 8-byte aligned | |
1273 ** memory, the size of each page buffer (sz), and the number of pages (N). | |
1274 ** The sz argument should be the size of the largest database page | |
1275 ** (a power of two between 512 and 32768) plus a little extra for each | |
1276 ** page header. ^The page header size is 20 to 40 bytes depending on | |
1277 ** the host architecture. ^It is harmless, apart from the wasted memory, | |
1278 ** to make sz a little too large. The first | |
1279 ** argument should point to an allocation of at least sz*N bytes of memory. | |
1280 ** ^SQLite will use the memory provided by the first argument to satisfy its | |
1281 ** memory needs for the first N pages that it adds to cache. ^If additional | |
1282 ** page cache memory is needed beyond what is provided by this option, then | |
1283 ** SQLite goes to [sqlite3_malloc()] for the additional storage space. | |
1284 ** ^The implementation might use one or more of the N buffers to hold | |
1285 ** memory accounting information. The pointer in the first argument must | |
1286 ** be aligned to an 8-byte boundary or subsequent behavior of SQLite | |
1287 ** will be undefined.</dd> | |
1288 ** | |
1289 ** <dt>SQLITE_CONFIG_HEAP</dt> | |
1290 ** <dd> ^This option specifies a static memory buffer that SQLite will use | |
1291 ** for all of its dynamic memory allocation needs beyond those provided | |
1292 ** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE]. | |
1293 ** There are three arguments: An 8-byte aligned pointer to the memory, | |
1294 ** the number of bytes in the memory buffer, and the minimum allocation size. | |
1295 ** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts | |
1296 ** to using its default memory allocator (the system malloc() implementation), | |
1297 ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the | |
1298 ** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or | |
1299 ** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory | |
1300 ** allocator is engaged to handle all of SQLites memory allocation needs. | |
1301 ** The first pointer (the memory pointer) must be aligned to an 8-byte | |
1302 ** boundary or subsequent behavior of SQLite will be undefined.</dd> | |
1303 ** | |
1304 ** <dt>SQLITE_CONFIG_MUTEX</dt> | |
1305 ** <dd> ^(This option takes a single argument which is a pointer to an | |
1306 ** instance of the [sqlite3_mutex_methods] structure. The argument specifies | |
1307 ** alternative low-level mutex routines to be used in place | |
1308 ** the mutex routines built into SQLite.)^ ^SQLite makes a copy of the | |
1309 ** content of the [sqlite3_mutex_methods] structure before the call to | |
1310 ** [sqlite3_config()] returns. ^If SQLite is compiled with | |
1311 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then | |
1312 ** the entire mutexing subsystem is omitted from the build and hence calls to | |
1313 ** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will | |
1314 ** return [SQLITE_ERROR].</dd> | |
1315 ** | |
1316 ** <dt>SQLITE_CONFIG_GETMUTEX</dt> | |
1317 ** <dd> ^(This option takes a single argument which is a pointer to an | |
1318 ** instance of the [sqlite3_mutex_methods] structure. The | |
1319 ** [sqlite3_mutex_methods] | |
1320 ** structure is filled with the currently defined mutex routines.)^ | |
1321 ** This option can be used to overload the default mutex allocation | |
1322 ** routines with a wrapper used to track mutex usage for performance | |
1323 ** profiling or testing, for example. ^If SQLite is compiled with | |
1324 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then | |
1325 ** the entire mutexing subsystem is omitted from the build and hence calls to | |
1326 ** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will | |
1327 ** return [SQLITE_ERROR].</dd> | |
1328 ** | |
1329 ** <dt>SQLITE_CONFIG_LOOKASIDE</dt> | |
1330 ** <dd> ^(This option takes two arguments that determine the default | |
1331 ** memory allocation for the lookaside memory allocator on each | |
1332 ** [database connection]. The first argument is the | |
1333 ** size of each lookaside buffer slot and the second is the number of | |
1334 ** slots allocated to each database connection.)^ ^(This option sets the | |
1335 ** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] | |
1336 ** verb to [sqlite3_db_config()] can be used to change the lookaside | |
1337 ** configuration on individual connections.)^ </dd> | |
1338 ** | |
1339 ** <dt>SQLITE_CONFIG_PCACHE</dt> | |
1340 ** <dd> ^(This option takes a single argument which is a pointer to | |
1341 ** an [sqlite3_pcache_methods] object. This object specifies the interface | |
1342 ** to a custom page cache implementation.)^ ^SQLite makes a copy of the | |
1343 ** object and uses it for page cache memory allocations.</dd> | |
1344 ** | |
1345 ** <dt>SQLITE_CONFIG_GETPCACHE</dt> | |
1346 ** <dd> ^(This option takes a single argument which is a pointer to an | |
1347 ** [sqlite3_pcache_methods] object. SQLite copies of the current | |
1348 ** page cache implementation into that object.)^ </dd> | |
1349 ** | |
1350 ** <dt>SQLITE_CONFIG_LOG</dt> | |
1351 ** <dd> ^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a | |
1352 ** function with a call signature of void(*)(void*,int,const char*), | |
1353 ** and a pointer to void. ^If the function pointer is not NULL, it is | |
1354 ** invoked by [sqlite3_log()] to process each logging event. ^If the | |
1355 ** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. | |
1356 ** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is | |
1357 ** passed through as the first parameter to the application-defined logger | |
1358 ** function whenever that function is invoked. ^The second parameter to | |
1359 ** the logger function is a copy of the first parameter to the corresponding | |
1360 ** [sqlite3_log()] call and is intended to be a [result code] or an | |
1361 ** [extended result code]. ^The third parameter passed to the logger is | |
1362 ** log message after formatting via [sqlite3_snprintf()]. | |
1363 ** The SQLite logging interface is not reentrant; the logger function | |
1364 ** supplied by the application must not invoke any SQLite interface. | |
1365 ** In a multi-threaded application, the application-defined logger | |
1366 ** function must be threadsafe. </dd> | |
1367 ** | |
1368 ** </dl> | |
1369 */ | |
1370 #define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ | |
1371 #define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ | |
1372 #define SQLITE_CONFIG_SERIALIZED 3 /* nil */ | |
1373 #define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ | |
1374 #define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ | |
1375 #define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ | |
1376 #define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ | |
1377 #define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ | |
1378 #define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ | |
1379 #define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ | |
1380 #define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ | |
1381 /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ | |
1382 #define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ | |
1383 #define SQLITE_CONFIG_PCACHE 14 /* sqlite3_pcache_methods* */ | |
1384 #define SQLITE_CONFIG_GETPCACHE 15 /* sqlite3_pcache_methods* */ | |
1385 #define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ | |
1386 | |
1387 /* | |
1388 ** CAPI3REF: Database Connection Configuration Options | |
1389 ** | |
1390 ** These constants are the available integer configuration options that | |
1391 ** can be passed as the second argument to the [sqlite3_db_config()] interface. | |
1392 ** | |
1393 ** New configuration options may be added in future releases of SQLite. | |
1394 ** Existing configuration options might be discontinued. Applications | |
1395 ** should check the return code from [sqlite3_db_config()] to make sure that | |
1396 ** the call worked. ^The [sqlite3_db_config()] interface will return a | |
1397 ** non-zero [error code] if a discontinued or unsupported configuration option | |
1398 ** is invoked. | |
1399 ** | |
1400 ** <dl> | |
1401 ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> | |
1402 ** <dd> ^This option takes three additional arguments that determine the | |
1403 ** [lookaside memory allocator] configuration for the [database connection]. | |
1404 ** ^The first argument (the third parameter to [sqlite3_db_config()] is a | |
1405 ** pointer to an memory buffer to use for lookaside memory. | |
1406 ** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb | |
1407 ** may be NULL in which case SQLite will allocate the | |
1408 ** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the | |
1409 ** size of each lookaside buffer slot. ^The third argument is the number of | |
1410 ** slots. The size of the buffer in the first argument must be greater than | |
1411 ** or equal to the product of the second and third arguments. The buffer | |
1412 ** must be aligned to an 8-byte boundary. ^If the second argument to | |
1413 ** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally | |
1414 ** rounded down to the next smaller | |
1415 ** multiple of 8. See also: [SQLITE_CONFIG_LOOKASIDE]</dd> | |
1416 ** | |
1417 ** </dl> | |
1418 */ | |
1419 #define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ | |
1420 | |
1421 | |
1422 /* | |
1423 ** CAPI3REF: Enable Or Disable Extended Result Codes | |
1424 ** | |
1425 ** ^The sqlite3_extended_result_codes() routine enables or disables the | |
1426 ** [extended result codes] feature of SQLite. ^The extended result | |
1427 ** codes are disabled by default for historical compatibility. | |
1428 */ | |
1429 SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff); | |
1430 | |
1431 /* | |
1432 ** CAPI3REF: Last Insert Rowid | |
1433 ** | |
1434 ** ^Each entry in an SQLite table has a unique 64-bit signed | |
1435 ** integer key called the [ROWID | "rowid"]. ^The rowid is always available | |
1436 ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those | |
1437 ** names are not also used by explicitly declared columns. ^If | |
1438 ** the table has a column of type [INTEGER PRIMARY KEY] then that column | |
1439 ** is another alias for the rowid. | |
1440 ** | |
1441 ** ^This routine returns the [rowid] of the most recent | |
1442 ** successful [INSERT] into the database from the [database connection] | |
1443 ** in the first argument. ^If no successful [INSERT]s | |
1444 ** have ever occurred on that database connection, zero is returned. | |
1445 ** | |
1446 ** ^(If an [INSERT] occurs within a trigger, then the [rowid] of the inserted | |
1447 ** row is returned by this routine as long as the trigger is running. | |
1448 ** But once the trigger terminates, the value returned by this routine | |
1449 ** reverts to the last value inserted before the trigger fired.)^ | |
1450 ** | |
1451 ** ^An [INSERT] that fails due to a constraint violation is not a | |
1452 ** successful [INSERT] and does not change the value returned by this | |
1453 ** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, | |
1454 ** and INSERT OR ABORT make no changes to the return value of this | |
1455 ** routine when their insertion fails. ^(When INSERT OR REPLACE | |
1456 ** encounters a constraint violation, it does not fail. The | |
1457 ** INSERT continues to completion after deleting rows that caused | |
1458 ** the constraint problem so INSERT OR REPLACE will always change | |
1459 ** the return value of this interface.)^ | |
1460 ** | |
1461 ** ^For the purposes of this routine, an [INSERT] is considered to | |
1462 ** be successful even if it is subsequently rolled back. | |
1463 ** | |
1464 ** This function is accessible to SQL statements via the | |
1465 ** [last_insert_rowid() SQL function]. | |
1466 ** | |
1467 ** If a separate thread performs a new [INSERT] on the same | |
1468 ** database connection while the [sqlite3_last_insert_rowid()] | |
1469 ** function is running and thus changes the last insert [rowid], | |
1470 ** then the value returned by [sqlite3_last_insert_rowid()] is | |
1471 ** unpredictable and might not equal either the old or the new | |
1472 ** last insert [rowid]. | |
1473 */ | |
1474 SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); | |
1475 | |
1476 /* | |
1477 ** CAPI3REF: Count The Number Of Rows Modified | |
1478 ** | |
1479 ** ^This function returns the number of database rows that were changed | |
1480 ** or inserted or deleted by the most recently completed SQL statement | |
1481 ** on the [database connection] specified by the first parameter. | |
1482 ** ^(Only changes that are directly specified by the [INSERT], [UPDATE], | |
1483 ** or [DELETE] statement are counted. Auxiliary changes caused by | |
1484 ** triggers or [foreign key actions] are not counted.)^ Use the | |
1485 ** [sqlite3_total_changes()] function to find the total number of changes | |
1486 ** including changes caused by triggers and foreign key actions. | |
1487 ** | |
1488 ** ^Changes to a view that are simulated by an [INSTEAD OF trigger] | |
1489 ** are not counted. Only real table changes are counted. | |
1490 ** | |
1491 ** ^(A "row change" is a change to a single row of a single table | |
1492 ** caused by an INSERT, DELETE, or UPDATE statement. Rows that | |
1493 ** are changed as side effects of [REPLACE] constraint resolution, | |
1494 ** rollback, ABORT processing, [DROP TABLE], or by any other | |
1495 ** mechanisms do not count as direct row changes.)^ | |
1496 ** | |
1497 ** A "trigger context" is a scope of execution that begins and | |
1498 ** ends with the script of a [CREATE TRIGGER | trigger]. | |
1499 ** Most SQL statements are | |
1500 ** evaluated outside of any trigger. This is the "top level" | |
1501 ** trigger context. If a trigger fires from the top level, a | |
1502 ** new trigger context is entered for the duration of that one | |
1503 ** trigger. Subtriggers create subcontexts for their duration. | |
1504 ** | |
1505 ** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does | |
1506 ** not create a new trigger context. | |
1507 ** | |
1508 ** ^This function returns the number of direct row changes in the | |
1509 ** most recent INSERT, UPDATE, or DELETE statement within the same | |
1510 ** trigger context. | |
1511 ** | |
1512 ** ^Thus, when called from the top level, this function returns the | |
1513 ** number of changes in the most recent INSERT, UPDATE, or DELETE | |
1514 ** that also occurred at the top level. ^(Within the body of a trigger, | |
1515 ** the sqlite3_changes() interface can be called to find the number of | |
1516 ** changes in the most recently completed INSERT, UPDATE, or DELETE | |
1517 ** statement within the body of the same trigger. | |
1518 ** However, the number returned does not include changes | |
1519 ** caused by subtriggers since those have their own context.)^ | |
1520 ** | |
1521 ** See also the [sqlite3_total_changes()] interface, the | |
1522 ** [count_changes pragma], and the [changes() SQL function]. | |
1523 ** | |
1524 ** If a separate thread makes changes on the same database connection | |
1525 ** while [sqlite3_changes()] is running then the value returned | |
1526 ** is unpredictable and not meaningful. | |
1527 */ | |
1528 SQLITE_API int sqlite3_changes(sqlite3*); | |
1529 | |
1530 /* | |
1531 ** CAPI3REF: Total Number Of Rows Modified | |
1532 ** | |
1533 ** ^This function returns the number of row changes caused by [INSERT], | |
1534 ** [UPDATE] or [DELETE] statements since the [database connection] was opened. | |
1535 ** ^(The count returned by sqlite3_total_changes() includes all changes | |
1536 ** from all [CREATE TRIGGER | trigger] contexts and changes made by | |
1537 ** [foreign key actions]. However, | |
1538 ** the count does not include changes used to implement [REPLACE] constraints, | |
1539 ** do rollbacks or ABORT processing, or [DROP TABLE] processing. The | |
1540 ** count does not include rows of views that fire an [INSTEAD OF trigger], | |
1541 ** though if the INSTEAD OF trigger makes changes of its own, those changes | |
1542 ** are counted.)^ | |
1543 ** ^The sqlite3_total_changes() function counts the changes as soon as | |
1544 ** the statement that makes them is completed (when the statement handle | |
1545 ** is passed to [sqlite3_reset()] or [sqlite3_finalize()]). | |
1546 ** | |
1547 ** See also the [sqlite3_changes()] interface, the | |
1548 ** [count_changes pragma], and the [total_changes() SQL function]. | |
1549 ** | |
1550 ** If a separate thread makes changes on the same database connection | |
1551 ** while [sqlite3_total_changes()] is running then the value | |
1552 ** returned is unpredictable and not meaningful. | |
1553 */ | |
1554 SQLITE_API int sqlite3_total_changes(sqlite3*); | |
1555 | |
1556 /* | |
1557 ** CAPI3REF: Interrupt A Long-Running Query | |
1558 ** | |
1559 ** ^This function causes any pending database operation to abort and | |
1560 ** return at its earliest opportunity. This routine is typically | |
1561 ** called in response to a user action such as pressing "Cancel" | |
1562 ** or Ctrl-C where the user wants a long query operation to halt | |
1563 ** immediately. | |
1564 ** | |
1565 ** ^It is safe to call this routine from a thread different from the | |
1566 ** thread that is currently running the database operation. But it | |
1567 ** is not safe to call this routine with a [database connection] that | |
1568 ** is closed or might close before sqlite3_interrupt() returns. | |
1569 ** | |
1570 ** ^If an SQL operation is very nearly finished at the time when | |
1571 ** sqlite3_interrupt() is called, then it might not have an opportunity | |
1572 ** to be interrupted and might continue to completion. | |
1573 ** | |
1574 ** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. | |
1575 ** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE | |
1576 ** that is inside an explicit transaction, then the entire transaction | |
1577 ** will be rolled back automatically. | |
1578 ** | |
1579 ** ^The sqlite3_interrupt(D) call is in effect until all currently running | |
1580 ** SQL statements on [database connection] D complete. ^Any new SQL statements | |
1581 ** that are started after the sqlite3_interrupt() call and before the | |
1582 ** running statements reaches zero are interrupted as if they had been | |
1583 ** running prior to the sqlite3_interrupt() call. ^New SQL statements | |
1584 ** that are started after the running statement count reaches zero are | |
1585 ** not effected by the sqlite3_interrupt(). | |
1586 ** ^A call to sqlite3_interrupt(D) that occurs when there are no running | |
1587 ** SQL statements is a no-op and has no effect on SQL statements | |
1588 ** that are started after the sqlite3_interrupt() call returns. | |
1589 ** | |
1590 ** If the database connection closes while [sqlite3_interrupt()] | |
1591 ** is running then bad things will likely happen. | |
1592 */ | |
1593 SQLITE_API void sqlite3_interrupt(sqlite3*); | |
1594 | |
1595 /* | |
1596 ** CAPI3REF: Determine If An SQL Statement Is Complete | |
1597 ** | |
1598 ** These routines are useful during command-line input to determine if the | |
1599 ** currently entered text seems to form a complete SQL statement or | |
1600 ** if additional input is needed before sending the text into | |
1601 ** SQLite for parsing. ^These routines return 1 if the input string | |
1602 ** appears to be a complete SQL statement. ^A statement is judged to be | |
1603 ** complete if it ends with a semicolon token and is not a prefix of a | |
1604 ** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within | |
1605 ** string literals or quoted identifier names or comments are not | |
1606 ** independent tokens (they are part of the token in which they are | |
1607 ** embedded) and thus do not count as a statement terminator. ^Whitespace | |
1608 ** and comments that follow the final semicolon are ignored. | |
1609 ** | |
1610 ** ^These routines return 0 if the statement is incomplete. ^If a | |
1611 ** memory allocation fails, then SQLITE_NOMEM is returned. | |
1612 ** | |
1613 ** ^These routines do not parse the SQL statements thus | |
1614 ** will not detect syntactically incorrect SQL. | |
1615 ** | |
1616 ** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior | |
1617 ** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked | |
1618 ** automatically by sqlite3_complete16(). If that initialization fails, | |
1619 ** then the return value from sqlite3_complete16() will be non-zero | |
1620 ** regardless of whether or not the input SQL is complete.)^ | |
1621 ** | |
1622 ** The input to [sqlite3_complete()] must be a zero-terminated | |
1623 ** UTF-8 string. | |
1624 ** | |
1625 ** The input to [sqlite3_complete16()] must be a zero-terminated | |
1626 ** UTF-16 string in native byte order. | |
1627 */ | |
1628 SQLITE_API int sqlite3_complete(const char *sql); | |
1629 SQLITE_API int sqlite3_complete16(const void *sql); | |
1630 | |
1631 /* | |
1632 ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors | |
1633 ** | |
1634 ** ^This routine sets a callback function that might be invoked whenever | |
1635 ** an attempt is made to open a database table that another thread | |
1636 ** or process has locked. | |
1637 ** | |
1638 ** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] | |
1639 ** is returned immediately upon encountering the lock. ^If the busy callback | |
1640 ** is not NULL, then the callback might be invoked with two arguments. | |
1641 ** | |
1642 ** ^The first argument to the busy handler is a copy of the void* pointer which | |
1643 ** is the third argument to sqlite3_busy_handler(). ^The second argument to | |
1644 ** the busy handler callback is the number of times that the busy handler has | |
1645 ** been invoked for this locking event. ^If the | |
1646 ** busy callback returns 0, then no additional attempts are made to | |
1647 ** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned. | |
1648 ** ^If the callback returns non-zero, then another attempt | |
1649 ** is made to open the database for reading and the cycle repeats. | |
1650 ** | |
1651 ** The presence of a busy handler does not guarantee that it will be invoked | |
1652 ** when there is lock contention. ^If SQLite determines that invoking the busy | |
1653 ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] | |
1654 ** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler. | |
1655 ** Consider a scenario where one process is holding a read lock that | |
1656 ** it is trying to promote to a reserved lock and | |
1657 ** a second process is holding a reserved lock that it is trying | |
1658 ** to promote to an exclusive lock. The first process cannot proceed | |
1659 ** because it is blocked by the second and the second process cannot | |
1660 ** proceed because it is blocked by the first. If both processes | |
1661 ** invoke the busy handlers, neither will make any progress. Therefore, | |
1662 ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this | |
1663 ** will induce the first process to release its read lock and allow | |
1664 ** the second process to proceed. | |
1665 ** | |
1666 ** ^The default busy callback is NULL. | |
1667 ** | |
1668 ** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED] | |
1669 ** when SQLite is in the middle of a large transaction where all the | |
1670 ** changes will not fit into the in-memory cache. SQLite will | |
1671 ** already hold a RESERVED lock on the database file, but it needs | |
1672 ** to promote this lock to EXCLUSIVE so that it can spill cache | |
1673 ** pages into the database file without harm to concurrent | |
1674 ** readers. ^If it is unable to promote the lock, then the in-memory | |
1675 ** cache will be left in an inconsistent state and so the error | |
1676 ** code is promoted from the relatively benign [SQLITE_BUSY] to | |
1677 ** the more severe [SQLITE_IOERR_BLOCKED]. ^This error code promotion | |
1678 ** forces an automatic rollback of the changes. See the | |
1679 ** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError"> | |
1680 ** CorruptionFollowingBusyError</a> wiki page for a discussion of why | |
1681 ** this is important. | |
1682 ** | |
1683 ** ^(There can only be a single busy handler defined for each | |
1684 ** [database connection]. Setting a new busy handler clears any | |
1685 ** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] | |
1686 ** will also set or clear the busy handler. | |
1687 ** | |
1688 ** The busy callback should not take any actions which modify the | |
1689 ** database connection that invoked the busy handler. Any such actions | |
1690 ** result in undefined behavior. | |
1691 ** | |
1692 ** A busy handler must not close the database connection | |
1693 ** or [prepared statement] that invoked the busy handler. | |
1694 */ | |
1695 SQLITE_API int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*); | |
1696 | |
1697 /* | |
1698 ** CAPI3REF: Set A Busy Timeout | |
1699 ** | |
1700 ** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps | |
1701 ** for a specified amount of time when a table is locked. ^The handler | |
1702 ** will sleep multiple times until at least "ms" milliseconds of sleeping | |
1703 ** have accumulated. ^After at least "ms" milliseconds of sleeping, | |
1704 ** the handler returns 0 which causes [sqlite3_step()] to return | |
1705 ** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]. | |
1706 ** | |
1707 ** ^Calling this routine with an argument less than or equal to zero | |
1708 ** turns off all busy handlers. | |
1709 ** | |
1710 ** ^(There can only be a single busy handler for a particular | |
1711 ** [database connection] any any given moment. If another busy handler | |
1712 ** was defined (using [sqlite3_busy_handler()]) prior to calling | |
1713 ** this routine, that other busy handler is cleared.)^ | |
1714 */ | |
1715 SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms); | |
1716 | |
1717 /* | |
1718 ** CAPI3REF: Convenience Routines For Running Queries | |
1719 ** | |
1720 ** Definition: A <b>result table</b> is memory data structure created by the | |
1721 ** [sqlite3_get_table()] interface. A result table records the | |
1722 ** complete query results from one or more queries. | |
1723 ** | |
1724 ** The table conceptually has a number of rows and columns. But | |
1725 ** these numbers are not part of the result table itself. These | |
1726 ** numbers are obtained separately. Let N be the number of rows | |
1727 ** and M be the number of columns. | |
1728 ** | |
1729 ** A result table is an array of pointers to zero-terminated UTF-8 strings. | |
1730 ** There are (N+1)*M elements in the array. The first M pointers point | |
1731 ** to zero-terminated strings that contain the names of the columns. | |
1732 ** The remaining entries all point to query results. NULL values result | |
1733 ** in NULL pointers. All other values are in their UTF-8 zero-terminated | |
1734 ** string representation as returned by [sqlite3_column_text()]. | |
1735 ** | |
1736 ** A result table might consist of one or more memory allocations. | |
1737 ** It is not safe to pass a result table directly to [sqlite3_free()]. | |
1738 ** A result table should be deallocated using [sqlite3_free_table()]. | |
1739 ** | |
1740 ** As an example of the result table format, suppose a query result | |
1741 ** is as follows: | |
1742 ** | |
1743 ** <blockquote><pre> | |
1744 ** Name | Age | |
1745 ** ----------------------- | |
1746 ** Alice | 43 | |
1747 ** Bob | 28 | |
1748 ** Cindy | 21 | |
1749 ** </pre></blockquote> | |
1750 ** | |
1751 ** There are two column (M==2) and three rows (N==3). Thus the | |
1752 ** result table has 8 entries. Suppose the result table is stored | |
1753 ** in an array names azResult. Then azResult holds this content: | |
1754 ** | |
1755 ** <blockquote><pre> | |
1756 ** azResult[0] = "Name"; | |
1757 ** azResult[1] = "Age"; | |
1758 ** azResult[2] = "Alice"; | |
1759 ** azResult[3] = "43"; | |
1760 ** azResult[4] = "Bob"; | |
1761 ** azResult[5] = "28"; | |
1762 ** azResult[6] = "Cindy"; | |
1763 ** azResult[7] = "21"; | |
1764 ** </pre></blockquote> | |
1765 ** | |
1766 ** ^The sqlite3_get_table() function evaluates one or more | |
1767 ** semicolon-separated SQL statements in the zero-terminated UTF-8 | |
1768 ** string of its 2nd parameter and returns a result table to the | |
1769 ** pointer given in its 3rd parameter. | |
1770 ** | |
1771 ** After the application has finished with the result from sqlite3_get_table(), | |
1772 ** it should pass the result table pointer to sqlite3_free_table() in order to | |
1773 ** release the memory that was malloced. Because of the way the | |
1774 ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling | |
1775 ** function must not try to call [sqlite3_free()] directly. Only | |
1776 ** [sqlite3_free_table()] is able to release the memory properly and safely. | |
1777 ** | |
1778 ** ^(The sqlite3_get_table() interface is implemented as a wrapper around | |
1779 ** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access | |
1780 ** to any internal data structures of SQLite. It uses only the public | |
1781 ** interface defined here. As a consequence, errors that occur in the | |
1782 ** wrapper layer outside of the internal [sqlite3_exec()] call are not | |
1783 ** reflected in subsequent calls to [sqlite3_errcode()] or | |
1784 ** [sqlite3_errmsg()].)^ | |
1785 */ | |
1786 SQLITE_API int sqlite3_get_table( | |
1787 sqlite3 *db, /* An open database */ | |
1788 const char *zSql, /* SQL to be evaluated */ | |
1789 char ***pazResult, /* Results of the query */ | |
1790 int *pnRow, /* Number of result rows written here */ | |
1791 int *pnColumn, /* Number of result columns written here */ | |
1792 char **pzErrmsg /* Error msg written here */ | |
1793 ); | |
1794 SQLITE_API void sqlite3_free_table(char **result); | |
1795 | |
1796 /* | |
1797 ** CAPI3REF: Formatted String Printing Functions | |
1798 ** | |
1799 ** These routines are work-alikes of the "printf()" family of functions | |
1800 ** from the standard C library. | |
1801 ** | |
1802 ** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their | |
1803 ** results into memory obtained from [sqlite3_malloc()]. | |
1804 ** The strings returned by these two routines should be | |
1805 ** released by [sqlite3_free()]. ^Both routines return a | |
1806 ** NULL pointer if [sqlite3_malloc()] is unable to allocate enough | |
1807 ** memory to hold the resulting string. | |
1808 ** | |
1809 ** ^(In sqlite3_snprintf() routine is similar to "snprintf()" from | |
1810 ** the standard C library. The result is written into the | |
1811 ** buffer supplied as the second parameter whose size is given by | |
1812 ** the first parameter. Note that the order of the | |
1813 ** first two parameters is reversed from snprintf().)^ This is an | |
1814 ** historical accident that cannot be fixed without breaking | |
1815 ** backwards compatibility. ^(Note also that sqlite3_snprintf() | |
1816 ** returns a pointer to its buffer instead of the number of | |
1817 ** characters actually written into the buffer.)^ We admit that | |
1818 ** the number of characters written would be a more useful return | |
1819 ** value but we cannot change the implementation of sqlite3_snprintf() | |
1820 ** now without breaking compatibility. | |
1821 ** | |
1822 ** ^As long as the buffer size is greater than zero, sqlite3_snprintf() | |
1823 ** guarantees that the buffer is always zero-terminated. ^The first | |
1824 ** parameter "n" is the total size of the buffer, including space for | |
1825 ** the zero terminator. So the longest string that can be completely | |
1826 ** written will be n-1 characters. | |
1827 ** | |
1828 ** These routines all implement some additional formatting | |
1829 ** options that are useful for constructing SQL statements. | |
1830 ** All of the usual printf() formatting options apply. In addition, there | |
1831 ** is are "%q", "%Q", and "%z" options. | |
1832 ** | |
1833 ** ^(The %q option works like %s in that it substitutes a null-terminated | |
1834 ** string from the argument list. But %q also doubles every '\'' character. | |
1835 ** %q is designed for use inside a string literal.)^ By doubling each '\'' | |
1836 ** character it escapes that character and allows it to be inserted into | |
1837 ** the string. | |
1838 ** | |
1839 ** For example, assume the string variable zText contains text as follows: | |
1840 ** | |
1841 ** <blockquote><pre> | |
1842 ** char *zText = "It's a happy day!"; | |
1843 ** </pre></blockquote> | |
1844 ** | |
1845 ** One can use this text in an SQL statement as follows: | |
1846 ** | |
1847 ** <blockquote><pre> | |
1848 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); | |
1849 ** sqlite3_exec(db, zSQL, 0, 0, 0); | |
1850 ** sqlite3_free(zSQL); | |
1851 ** </pre></blockquote> | |
1852 ** | |
1853 ** Because the %q format string is used, the '\'' character in zText | |
1854 ** is escaped and the SQL generated is as follows: | |
1855 ** | |
1856 ** <blockquote><pre> | |
1857 ** INSERT INTO table1 VALUES('It''s a happy day!') | |
1858 ** </pre></blockquote> | |
1859 ** | |
1860 ** This is correct. Had we used %s instead of %q, the generated SQL | |
1861 ** would have looked like this: | |
1862 ** | |
1863 ** <blockquote><pre> | |
1864 ** INSERT INTO table1 VALUES('It's a happy day!'); | |
1865 ** </pre></blockquote> | |
1866 ** | |
1867 ** This second example is an SQL syntax error. As a general rule you should | |
1868 ** always use %q instead of %s when inserting text into a string literal. | |
1869 ** | |
1870 ** ^(The %Q option works like %q except it also adds single quotes around | |
1871 ** the outside of the total string. Additionally, if the parameter in the | |
1872 ** argument list is a NULL pointer, %Q substitutes the text "NULL" (without | |
1873 ** single quotes).)^ So, for example, one could say: | |
1874 ** | |
1875 ** <blockquote><pre> | |
1876 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); | |
1877 ** sqlite3_exec(db, zSQL, 0, 0, 0); | |
1878 ** sqlite3_free(zSQL); | |
1879 ** </pre></blockquote> | |
1880 ** | |
1881 ** The code above will render a correct SQL statement in the zSQL | |
1882 ** variable even if the zText variable is a NULL pointer. | |
1883 ** | |
1884 ** ^(The "%z" formatting option works like "%s" but with the | |
1885 ** addition that after the string has been read and copied into | |
1886 ** the result, [sqlite3_free()] is called on the input string.)^ | |
1887 */ | |
1888 SQLITE_API char *sqlite3_mprintf(const char*,...); | |
1889 SQLITE_API char *sqlite3_vmprintf(const char*, va_list); | |
1890 SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...); | |
1891 | |
1892 /* | |
1893 ** CAPI3REF: Memory Allocation Subsystem | |
1894 ** | |
1895 ** The SQLite core uses these three routines for all of its own | |
1896 ** internal memory allocation needs. "Core" in the previous sentence | |
1897 ** does not include operating-system specific VFS implementation. The | |
1898 ** Windows VFS uses native malloc() and free() for some operations. | |
1899 ** | |
1900 ** ^The sqlite3_malloc() routine returns a pointer to a block | |
1901 ** of memory at least N bytes in length, where N is the parameter. | |
1902 ** ^If sqlite3_malloc() is unable to obtain sufficient free | |
1903 ** memory, it returns a NULL pointer. ^If the parameter N to | |
1904 ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns | |
1905 ** a NULL pointer. | |
1906 ** | |
1907 ** ^Calling sqlite3_free() with a pointer previously returned | |
1908 ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so | |
1909 ** that it might be reused. ^The sqlite3_free() routine is | |
1910 ** a no-op if is called with a NULL pointer. Passing a NULL pointer | |
1911 ** to sqlite3_free() is harmless. After being freed, memory | |
1912 ** should neither be read nor written. Even reading previously freed | |
1913 ** memory might result in a segmentation fault or other severe error. | |
1914 ** Memory corruption, a segmentation fault, or other severe error | |
1915 ** might result if sqlite3_free() is called with a non-NULL pointer that | |
1916 ** was not obtained from sqlite3_malloc() or sqlite3_realloc(). | |
1917 ** | |
1918 ** ^(The sqlite3_realloc() interface attempts to resize a | |
1919 ** prior memory allocation to be at least N bytes, where N is the | |
1920 ** second parameter. The memory allocation to be resized is the first | |
1921 ** parameter.)^ ^ If the first parameter to sqlite3_realloc() | |
1922 ** is a NULL pointer then its behavior is identical to calling | |
1923 ** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc(). | |
1924 ** ^If the second parameter to sqlite3_realloc() is zero or | |
1925 ** negative then the behavior is exactly the same as calling | |
1926 ** sqlite3_free(P) where P is the first parameter to sqlite3_realloc(). | |
1927 ** ^sqlite3_realloc() returns a pointer to a memory allocation | |
1928 ** of at least N bytes in size or NULL if sufficient memory is unavailable. | |
1929 ** ^If M is the size of the prior allocation, then min(N,M) bytes | |
1930 ** of the prior allocation are copied into the beginning of buffer returned | |
1931 ** by sqlite3_realloc() and the prior allocation is freed. | |
1932 ** ^If sqlite3_realloc() returns NULL, then the prior allocation | |
1933 ** is not freed. | |
1934 ** | |
1935 ** ^The memory returned by sqlite3_malloc() and sqlite3_realloc() | |
1936 ** is always aligned to at least an 8 byte boundary. | |
1937 ** | |
1938 ** In SQLite version 3.5.0 and 3.5.1, it was possible to define | |
1939 ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in | |
1940 ** implementation of these routines to be omitted. That capability | |
1941 ** is no longer provided. Only built-in memory allocators can be used. | |
1942 ** | |
1943 ** The Windows OS interface layer calls | |
1944 ** the system malloc() and free() directly when converting | |
1945 ** filenames between the UTF-8 encoding used by SQLite | |
1946 ** and whatever filename encoding is used by the particular Windows | |
1947 ** installation. Memory allocation errors are detected, but | |
1948 ** they are reported back as [SQLITE_CANTOPEN] or | |
1949 ** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. | |
1950 ** | |
1951 ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] | |
1952 ** must be either NULL or else pointers obtained from a prior | |
1953 ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have | |
1954 ** not yet been released. | |
1955 ** | |
1956 ** The application must not read or write any part of | |
1957 ** a block of memory after it has been released using | |
1958 ** [sqlite3_free()] or [sqlite3_realloc()]. | |
1959 */ | |
1960 SQLITE_API void *sqlite3_malloc(int); | |
1961 SQLITE_API void *sqlite3_realloc(void*, int); | |
1962 SQLITE_API void sqlite3_free(void*); | |
1963 | |
1964 /* | |
1965 ** CAPI3REF: Memory Allocator Statistics | |
1966 ** | |
1967 ** SQLite provides these two interfaces for reporting on the status | |
1968 ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] | |
1969 ** routines, which form the built-in memory allocation subsystem. | |
1970 ** | |
1971 ** ^The [sqlite3_memory_used()] routine returns the number of bytes | |
1972 ** of memory currently outstanding (malloced but not freed). | |
1973 ** ^The [sqlite3_memory_highwater()] routine returns the maximum | |
1974 ** value of [sqlite3_memory_used()] since the high-water mark | |
1975 ** was last reset. ^The values returned by [sqlite3_memory_used()] and | |
1976 ** [sqlite3_memory_highwater()] include any overhead | |
1977 ** added by SQLite in its implementation of [sqlite3_malloc()], | |
1978 ** but not overhead added by the any underlying system library | |
1979 ** routines that [sqlite3_malloc()] may call. | |
1980 ** | |
1981 ** ^The memory high-water mark is reset to the current value of | |
1982 ** [sqlite3_memory_used()] if and only if the parameter to | |
1983 ** [sqlite3_memory_highwater()] is true. ^The value returned | |
1984 ** by [sqlite3_memory_highwater(1)] is the high-water mark | |
1985 ** prior to the reset. | |
1986 */ | |
1987 SQLITE_API sqlite3_int64 sqlite3_memory_used(void); | |
1988 SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag); | |
1989 | |
1990 /* | |
1991 ** CAPI3REF: Pseudo-Random Number Generator | |
1992 ** | |
1993 ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to | |
1994 ** select random [ROWID | ROWIDs] when inserting new records into a table that | |
1995 ** already uses the largest possible [ROWID]. The PRNG is also used for | |
1996 ** the build-in random() and randomblob() SQL functions. This interface allows | |
1997 ** applications to access the same PRNG for other purposes. | |
1998 ** | |
1999 ** ^A call to this routine stores N bytes of randomness into buffer P. | |
2000 ** | |
2001 ** ^The first time this routine is invoked (either internally or by | |
2002 ** the application) the PRNG is seeded using randomness obtained | |
2003 ** from the xRandomness method of the default [sqlite3_vfs] object. | |
2004 ** ^On all subsequent invocations, the pseudo-randomness is generated | |
2005 ** internally and without recourse to the [sqlite3_vfs] xRandomness | |
2006 ** method. | |
2007 */ | |
2008 SQLITE_API void sqlite3_randomness(int N, void *P); | |
2009 | |
2010 /* | |
2011 ** CAPI3REF: Compile-Time Authorization Callbacks | |
2012 ** | |
2013 ** ^This routine registers a authorizer callback with a particular | |
2014 ** [database connection], supplied in the first argument. | |
2015 ** ^The authorizer callback is invoked as SQL statements are being compiled | |
2016 ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], | |
2017 ** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various | |
2018 ** points during the compilation process, as logic is being created | |
2019 ** to perform various actions, the authorizer callback is invoked to | |
2020 ** see if those actions are allowed. ^The authorizer callback should | |
2021 ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the | |
2022 ** specific action but allow the SQL statement to continue to be | |
2023 ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be | |
2024 ** rejected with an error. ^If the authorizer callback returns | |
2025 ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] | |
2026 ** then the [sqlite3_prepare_v2()] or equivalent call that triggered | |
2027 ** the authorizer will fail with an error message. | |
2028 ** | |
2029 ** When the callback returns [SQLITE_OK], that means the operation | |
2030 ** requested is ok. ^When the callback returns [SQLITE_DENY], the | |
2031 ** [sqlite3_prepare_v2()] or equivalent call that triggered the | |
2032 ** authorizer will fail with an error message explaining that | |
2033 ** access is denied. | |
2034 ** | |
2035 ** ^The first parameter to the authorizer callback is a copy of the third | |
2036 ** parameter to the sqlite3_set_authorizer() interface. ^The second parameter | |
2037 ** to the callback is an integer [SQLITE_COPY | action code] that specifies | |
2038 ** the particular action to be authorized. ^The third through sixth parameters | |
2039 ** to the callback are zero-terminated strings that contain additional | |
2040 ** details about the action to be authorized. | |
2041 ** | |
2042 ** ^If the action code is [SQLITE_READ] | |
2043 ** and the callback returns [SQLITE_IGNORE] then the | |
2044 ** [prepared statement] statement is constructed to substitute | |
2045 ** a NULL value in place of the table column that would have | |
2046 ** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] | |
2047 ** return can be used to deny an untrusted user access to individual | |
2048 ** columns of a table. | |
2049 ** ^If the action code is [SQLITE_DELETE] and the callback returns | |
2050 ** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the | |
2051 ** [truncate optimization] is disabled and all rows are deleted individually. | |
2052 ** | |
2053 ** An authorizer is used when [sqlite3_prepare | preparing] | |
2054 ** SQL statements from an untrusted source, to ensure that the SQL statements | |
2055 ** do not try to access data they are not allowed to see, or that they do not | |
2056 ** try to execute malicious statements that damage the database. For | |
2057 ** example, an application may allow a user to enter arbitrary | |
2058 ** SQL queries for evaluation by a database. But the application does | |
2059 ** not want the user to be able to make arbitrary changes to the | |
2060 ** database. An authorizer could then be put in place while the | |
2061 ** user-entered SQL is being [sqlite3_prepare | prepared] that | |
2062 ** disallows everything except [SELECT] statements. | |
2063 ** | |
2064 ** Applications that need to process SQL from untrusted sources | |
2065 ** might also consider lowering resource limits using [sqlite3_limit()] | |
2066 ** and limiting database size using the [max_page_count] [PRAGMA] | |
2067 ** in addition to using an authorizer. | |
2068 ** | |
2069 ** ^(Only a single authorizer can be in place on a database connection | |
2070 ** at a time. Each call to sqlite3_set_authorizer overrides the | |
2071 ** previous call.)^ ^Disable the authorizer by installing a NULL callback. | |
2072 ** The authorizer is disabled by default. | |
2073 ** | |
2074 ** The authorizer callback must not do anything that will modify | |
2075 ** the database connection that invoked the authorizer callback. | |
2076 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their | |
2077 ** database connections for the meaning of "modify" in this paragraph. | |
2078 ** | |
2079 ** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the | |
2080 ** statement might be re-prepared during [sqlite3_step()] due to a | |
2081 ** schema change. Hence, the application should ensure that the | |
2082 ** correct authorizer callback remains in place during the [sqlite3_step()]. | |
2083 ** | |
2084 ** ^Note that the authorizer callback is invoked only during | |
2085 ** [sqlite3_prepare()] or its variants. Authorization is not | |
2086 ** performed during statement evaluation in [sqlite3_step()], unless | |
2087 ** as stated in the previous paragraph, sqlite3_step() invokes | |
2088 ** sqlite3_prepare_v2() to reprepare a statement after a schema change. | |
2089 */ | |
2090 SQLITE_API int sqlite3_set_authorizer( | |
2091 sqlite3*, | |
2092 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), | |
2093 void *pUserData | |
2094 ); | |
2095 | |
2096 /* | |
2097 ** CAPI3REF: Authorizer Return Codes | |
2098 ** | |
2099 ** The [sqlite3_set_authorizer | authorizer callback function] must | |
2100 ** return either [SQLITE_OK] or one of these two constants in order | |
2101 ** to signal SQLite whether or not the action is permitted. See the | |
2102 ** [sqlite3_set_authorizer | authorizer documentation] for additional | |
2103 ** information. | |
2104 */ | |
2105 #define SQLITE_DENY 1 /* Abort the SQL statement with an error */ | |
2106 #define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ | |
2107 | |
2108 /* | |
2109 ** CAPI3REF: Authorizer Action Codes | |
2110 ** | |
2111 ** The [sqlite3_set_authorizer()] interface registers a callback function | |
2112 ** that is invoked to authorize certain SQL statement actions. The | |
2113 ** second parameter to the callback is an integer code that specifies | |
2114 ** what action is being authorized. These are the integer action codes that | |
2115 ** the authorizer callback may be passed. | |
2116 ** | |
2117 ** These action code values signify what kind of operation is to be | |
2118 ** authorized. The 3rd and 4th parameters to the authorization | |
2119 ** callback function will be parameters or NULL depending on which of these | |
2120 ** codes is used as the second parameter. ^(The 5th parameter to the | |
2121 ** authorizer callback is the name of the database ("main", "temp", | |
2122 ** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback | |
2123 ** is the name of the inner-most trigger or view that is responsible for | |
2124 ** the access attempt or NULL if this access attempt is directly from | |
2125 ** top-level SQL code. | |
2126 */ | |
2127 /******************************************* 3rd ************ 4th ***********/ | |
2128 #define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ | |
2129 #define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ | |
2130 #define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ | |
2131 #define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ | |
2132 #define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ | |
2133 #define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ | |
2134 #define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ | |
2135 #define SQLITE_CREATE_VIEW 8 /* View Name NULL */ | |
2136 #define SQLITE_DELETE 9 /* Table Name NULL */ | |
2137 #define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ | |
2138 #define SQLITE_DROP_TABLE 11 /* Table Name NULL */ | |
2139 #define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ | |
2140 #define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ | |
2141 #define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ | |
2142 #define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ | |
2143 #define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ | |
2144 #define SQLITE_DROP_VIEW 17 /* View Name NULL */ | |
2145 #define SQLITE_INSERT 18 /* Table Name NULL */ | |
2146 #define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ | |
2147 #define SQLITE_READ 20 /* Table Name Column Name */ | |
2148 #define SQLITE_SELECT 21 /* NULL NULL */ | |
2149 #define SQLITE_TRANSACTION 22 /* Operation NULL */ | |
2150 #define SQLITE_UPDATE 23 /* Table Name Column Name */ | |
2151 #define SQLITE_ATTACH 24 /* Filename NULL */ | |
2152 #define SQLITE_DETACH 25 /* Database Name NULL */ | |
2153 #define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ | |
2154 #define SQLITE_REINDEX 27 /* Index Name NULL */ | |
2155 #define SQLITE_ANALYZE 28 /* Table Name NULL */ | |
2156 #define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ | |
2157 #define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ | |
2158 #define SQLITE_FUNCTION 31 /* NULL Function Name */ | |
2159 #define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ | |
2160 #define SQLITE_COPY 0 /* No longer used */ | |
2161 | |
2162 /* | |
2163 ** CAPI3REF: Tracing And Profiling Functions | |
2164 ** | |
2165 ** These routines register callback functions that can be used for | |
2166 ** tracing and profiling the execution of SQL statements. | |
2167 ** | |
2168 ** ^The callback function registered by sqlite3_trace() is invoked at | |
2169 ** various times when an SQL statement is being run by [sqlite3_step()]. | |
2170 ** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the | |
2171 ** SQL statement text as the statement first begins executing. | |
2172 ** ^(Additional sqlite3_trace() callbacks might occur | |
2173 ** as each triggered subprogram is entered. The callbacks for triggers | |
2174 ** contain a UTF-8 SQL comment that identifies the trigger.)^ | |
2175 ** | |
2176 ** ^The callback function registered by sqlite3_profile() is invoked | |
2177 ** as each SQL statement finishes. ^The profile callback contains | |
2178 ** the original statement text and an estimate of wall-clock time | |
2179 ** of how long that statement took to run. | |
2180 */ | |
2181 SQLITE_API void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*); | |
2182 SQLITE_API SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*, | |
2183 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); | |
2184 | |
2185 /* | |
2186 ** CAPI3REF: Query Progress Callbacks | |
2187 ** | |
2188 ** ^This routine configures a callback function - the | |
2189 ** progress callback - that is invoked periodically during long | |
2190 ** running calls to [sqlite3_exec()], [sqlite3_step()] and | |
2191 ** [sqlite3_get_table()]. An example use for this | |
2192 ** interface is to keep a GUI updated during a large query. | |
2193 ** | |
2194 ** ^If the progress callback returns non-zero, the operation is | |
2195 ** interrupted. This feature can be used to implement a | |
2196 ** "Cancel" button on a GUI progress dialog box. | |
2197 ** | |
2198 ** The progress handler must not do anything that will modify | |
2199 ** the database connection that invoked the progress handler. | |
2200 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their | |
2201 ** database connections for the meaning of "modify" in this paragraph. | |
2202 ** | |
2203 */ | |
2204 SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); | |
2205 | |
2206 /* | |
2207 ** CAPI3REF: Opening A New Database Connection | |
2208 ** | |
2209 ** ^These routines open an SQLite database file whose name is given by the | |
2210 ** filename argument. ^The filename argument is interpreted as UTF-8 for | |
2211 ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte | |
2212 ** order for sqlite3_open16(). ^(A [database connection] handle is usually | |
2213 ** returned in *ppDb, even if an error occurs. The only exception is that | |
2214 ** if SQLite is unable to allocate memory to hold the [sqlite3] object, | |
2215 ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] | |
2216 ** object.)^ ^(If the database is opened (and/or created) successfully, then | |
2217 ** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The | |
2218 ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain | |
2219 ** an English language description of the error following a failure of any | |
2220 ** of the sqlite3_open() routines. | |
2221 ** | |
2222 ** ^The default encoding for the database will be UTF-8 if | |
2223 ** sqlite3_open() or sqlite3_open_v2() is called and | |
2224 ** UTF-16 in the native byte order if sqlite3_open16() is used. | |
2225 ** | |
2226 ** Whether or not an error occurs when it is opened, resources | |
2227 ** associated with the [database connection] handle should be released by | |
2228 ** passing it to [sqlite3_close()] when it is no longer required. | |
2229 ** | |
2230 ** The sqlite3_open_v2() interface works like sqlite3_open() | |
2231 ** except that it accepts two additional parameters for additional control | |
2232 ** over the new database connection. ^(The flags parameter to | |
2233 ** sqlite3_open_v2() can take one of | |
2234 ** the following three values, optionally combined with the | |
2235 ** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], | |
2236 ** and/or [SQLITE_OPEN_PRIVATECACHE] flags:)^ | |
2237 ** | |
2238 ** <dl> | |
2239 ** ^(<dt>[SQLITE_OPEN_READONLY]</dt> | |
2240 ** <dd>The database is opened in read-only mode. If the database does not | |
2241 ** already exist, an error is returned.</dd>)^ | |
2242 ** | |
2243 ** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> | |
2244 ** <dd>The database is opened for reading and writing if possible, or reading | |
2245 ** only if the file is write protected by the operating system. In either | |
2246 ** case the database must already exist, otherwise an error is returned.</dd>)^ | |
2247 ** | |
2248 ** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> | |
2249 ** <dd>The database is opened for reading and writing, and is creates it if | |
2250 ** it does not already exist. This is the behavior that is always used for | |
2251 ** sqlite3_open() and sqlite3_open16().</dd>)^ | |
2252 ** </dl> | |
2253 ** | |
2254 ** If the 3rd parameter to sqlite3_open_v2() is not one of the | |
2255 ** combinations shown above or one of the combinations shown above combined | |
2256 ** with the [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], | |
2257 ** [SQLITE_OPEN_SHAREDCACHE] and/or [SQLITE_OPEN_SHAREDCACHE] flags, | |
2258 ** then the behavior is undefined. | |
2259 ** | |
2260 ** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection | |
2261 ** opens in the multi-thread [threading mode] as long as the single-thread | |
2262 ** mode has not been set at compile-time or start-time. ^If the | |
2263 ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens | |
2264 ** in the serialized [threading mode] unless single-thread was | |
2265 ** previously selected at compile-time or start-time. | |
2266 ** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be | |
2267 ** eligible to use [shared cache mode], regardless of whether or not shared | |
2268 ** cache is enabled using [sqlite3_enable_shared_cache()]. ^The | |
2269 ** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not | |
2270 ** participate in [shared cache mode] even if it is enabled. | |
2271 ** | |
2272 ** ^If the filename is ":memory:", then a private, temporary in-memory database | |
2273 ** is created for the connection. ^This in-memory database will vanish when | |
2274 ** the database connection is closed. Future versions of SQLite might | |
2275 ** make use of additional special filenames that begin with the ":" character. | |
2276 ** It is recommended that when a database filename actually does begin with | |
2277 ** a ":" character you should prefix the filename with a pathname such as | |
2278 ** "./" to avoid ambiguity. | |
2279 ** | |
2280 ** ^If the filename is an empty string, then a private, temporary | |
2281 ** on-disk database will be created. ^This private database will be | |
2282 ** automatically deleted as soon as the database connection is closed. | |
2283 ** | |
2284 ** ^The fourth parameter to sqlite3_open_v2() is the name of the | |
2285 ** [sqlite3_vfs] object that defines the operating system interface that | |
2286 ** the new database connection should use. ^If the fourth parameter is | |
2287 ** a NULL pointer then the default [sqlite3_vfs] object is used. | |
2288 ** | |
2289 ** <b>Note to Windows users:</b> The encoding used for the filename argument | |
2290 ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever | |
2291 ** codepage is currently defined. Filenames containing international | |
2292 ** characters must be converted to UTF-8 prior to passing them into | |
2293 ** sqlite3_open() or sqlite3_open_v2(). | |
2294 */ | |
2295 SQLITE_API int sqlite3_open( | |
2296 const char *filename, /* Database filename (UTF-8) */ | |
2297 sqlite3 **ppDb /* OUT: SQLite db handle */ | |
2298 ); | |
2299 SQLITE_API int sqlite3_open16( | |
2300 const void *filename, /* Database filename (UTF-16) */ | |
2301 sqlite3 **ppDb /* OUT: SQLite db handle */ | |
2302 ); | |
2303 SQLITE_API int sqlite3_open_v2( | |
2304 const char *filename, /* Database filename (UTF-8) */ | |
2305 sqlite3 **ppDb, /* OUT: SQLite db handle */ | |
2306 int flags, /* Flags */ | |
2307 const char *zVfs /* Name of VFS module to use */ | |
2308 ); | |
2309 | |
2310 /* | |
2311 ** CAPI3REF: Error Codes And Messages | |
2312 ** | |
2313 ** ^The sqlite3_errcode() interface returns the numeric [result code] or | |
2314 ** [extended result code] for the most recent failed sqlite3_* API call | |
2315 ** associated with a [database connection]. If a prior API call failed | |
2316 ** but the most recent API call succeeded, the return value from | |
2317 ** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode() | |
2318 ** interface is the same except that it always returns the | |
2319 ** [extended result code] even when extended result codes are | |
2320 ** disabled. | |
2321 ** | |
2322 ** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language | |
2323 ** text that describes the error, as either UTF-8 or UTF-16 respectively. | |
2324 ** ^(Memory to hold the error message string is managed internally. | |
2325 ** The application does not need to worry about freeing the result. | |
2326 ** However, the error string might be overwritten or deallocated by | |
2327 ** subsequent calls to other SQLite interface functions.)^ | |
2328 ** | |
2329 ** When the serialized [threading mode] is in use, it might be the | |
2330 ** case that a second error occurs on a separate thread in between | |
2331 ** the time of the first error and the call to these interfaces. | |
2332 ** When that happens, the second error will be reported since these | |
2333 ** interfaces always report the most recent result. To avoid | |
2334 ** this, each thread can obtain exclusive use of the [database connection] D | |
2335 ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning | |
2336 ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after | |
2337 ** all calls to the interfaces listed here are completed. | |
2338 ** | |
2339 ** If an interface fails with SQLITE_MISUSE, that means the interface | |
2340 ** was invoked incorrectly by the application. In that case, the | |
2341 ** error code and message may or may not be set. | |
2342 */ | |
2343 SQLITE_API int sqlite3_errcode(sqlite3 *db); | |
2344 SQLITE_API int sqlite3_extended_errcode(sqlite3 *db); | |
2345 SQLITE_API const char *sqlite3_errmsg(sqlite3*); | |
2346 SQLITE_API const void *sqlite3_errmsg16(sqlite3*); | |
2347 | |
2348 /* | |
2349 ** CAPI3REF: SQL Statement Object | |
2350 ** KEYWORDS: {prepared statement} {prepared statements} | |
2351 ** | |
2352 ** An instance of this object represents a single SQL statement. | |
2353 ** This object is variously known as a "prepared statement" or a | |
2354 ** "compiled SQL statement" or simply as a "statement". | |
2355 ** | |
2356 ** The life of a statement object goes something like this: | |
2357 ** | |
2358 ** <ol> | |
2359 ** <li> Create the object using [sqlite3_prepare_v2()] or a related | |
2360 ** function. | |
2361 ** <li> Bind values to [host parameters] using the sqlite3_bind_*() | |
2362 ** interfaces. | |
2363 ** <li> Run the SQL by calling [sqlite3_step()] one or more times. | |
2364 ** <li> Reset the statement using [sqlite3_reset()] then go back | |
2365 ** to step 2. Do this zero or more times. | |
2366 ** <li> Destroy the object using [sqlite3_finalize()]. | |
2367 ** </ol> | |
2368 ** | |
2369 ** Refer to documentation on individual methods above for additional | |
2370 ** information. | |
2371 */ | |
2372 typedef struct sqlite3_stmt sqlite3_stmt; | |
2373 | |
2374 /* | |
2375 ** CAPI3REF: Run-time Limits | |
2376 ** | |
2377 ** ^(This interface allows the size of various constructs to be limited | |
2378 ** on a connection by connection basis. The first parameter is the | |
2379 ** [database connection] whose limit is to be set or queried. The | |
2380 ** second parameter is one of the [limit categories] that define a | |
2381 ** class of constructs to be size limited. The third parameter is the | |
2382 ** new limit for that construct. The function returns the old limit.)^ | |
2383 ** | |
2384 ** ^If the new limit is a negative number, the limit is unchanged. | |
2385 ** ^(For the limit category of SQLITE_LIMIT_XYZ there is a | |
2386 ** [limits | hard upper bound] | |
2387 ** set by a compile-time C preprocessor macro named | |
2388 ** [limits | SQLITE_MAX_XYZ]. | |
2389 ** (The "_LIMIT_" in the name is changed to "_MAX_".))^ | |
2390 ** ^Attempts to increase a limit above its hard upper bound are | |
2391 ** silently truncated to the hard upper bound. | |
2392 ** | |
2393 ** Run-time limits are intended for use in applications that manage | |
2394 ** both their own internal database and also databases that are controlled | |
2395 ** by untrusted external sources. An example application might be a | |
2396 ** web browser that has its own databases for storing history and | |
2397 ** separate databases controlled by JavaScript applications downloaded | |
2398 ** off the Internet. The internal databases can be given the | |
2399 ** large, default limits. Databases managed by external sources can | |
2400 ** be given much smaller limits designed to prevent a denial of service | |
2401 ** attack. Developers might also want to use the [sqlite3_set_authorizer()] | |
2402 ** interface to further control untrusted SQL. The size of the database | |
2403 ** created by an untrusted script can be contained using the | |
2404 ** [max_page_count] [PRAGMA]. | |
2405 ** | |
2406 ** New run-time limit categories may be added in future releases. | |
2407 */ | |
2408 SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal); | |
2409 | |
2410 /* | |
2411 ** CAPI3REF: Run-Time Limit Categories | |
2412 ** KEYWORDS: {limit category} {*limit categories} | |
2413 ** | |
2414 ** These constants define various performance limits | |
2415 ** that can be lowered at run-time using [sqlite3_limit()]. | |
2416 ** The synopsis of the meanings of the various limits is shown below. | |
2417 ** Additional information is available at [limits | Limits in SQLite]. | |
2418 ** | |
2419 ** <dl> | |
2420 ** ^(<dt>SQLITE_LIMIT_LENGTH</dt> | |
2421 ** <dd>The maximum size of any string or BLOB or table row.<dd>)^ | |
2422 ** | |
2423 ** ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> | |
2424 ** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ | |
2425 ** | |
2426 ** ^(<dt>SQLITE_LIMIT_COLUMN</dt> | |
2427 ** <dd>The maximum number of columns in a table definition or in the | |
2428 ** result set of a [SELECT] or the maximum number of columns in an index | |
2429 ** or in an ORDER BY or GROUP BY clause.</dd>)^ | |
2430 ** | |
2431 ** ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> | |
2432 ** <dd>The maximum depth of the parse tree on any expression.</dd>)^ | |
2433 ** | |
2434 ** ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> | |
2435 ** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ | |
2436 ** | |
2437 ** ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> | |
2438 ** <dd>The maximum number of instructions in a virtual machine program | |
2439 ** used to implement an SQL statement.</dd>)^ | |
2440 ** | |
2441 ** ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> | |
2442 ** <dd>The maximum number of arguments on a function.</dd>)^ | |
2443 ** | |
2444 ** ^(<dt>SQLITE_LIMIT_ATTACHED</dt> | |
2445 ** <dd>The maximum number of [ATTACH | attached databases].)^</dd> | |
2446 ** | |
2447 ** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> | |
2448 ** <dd>The maximum length of the pattern argument to the [LIKE] or | |
2449 ** [GLOB] operators.</dd>)^ | |
2450 ** | |
2451 ** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> | |
2452 ** <dd>The maximum number of variables in an SQL statement that can | |
2453 ** be bound.</dd>)^ | |
2454 ** | |
2455 ** ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> | |
2456 ** <dd>The maximum depth of recursion for triggers.</dd>)^ | |
2457 ** </dl> | |
2458 */ | |
2459 #define SQLITE_LIMIT_LENGTH 0 | |
2460 #define SQLITE_LIMIT_SQL_LENGTH 1 | |
2461 #define SQLITE_LIMIT_COLUMN 2 | |
2462 #define SQLITE_LIMIT_EXPR_DEPTH 3 | |
2463 #define SQLITE_LIMIT_COMPOUND_SELECT 4 | |
2464 #define SQLITE_LIMIT_VDBE_OP 5 | |
2465 #define SQLITE_LIMIT_FUNCTION_ARG 6 | |
2466 #define SQLITE_LIMIT_ATTACHED 7 | |
2467 #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 | |
2468 #define SQLITE_LIMIT_VARIABLE_NUMBER 9 | |
2469 #define SQLITE_LIMIT_TRIGGER_DEPTH 10 | |
2470 | |
2471 /* | |
2472 ** CAPI3REF: Compiling An SQL Statement | |
2473 ** KEYWORDS: {SQL statement compiler} | |
2474 ** | |
2475 ** To execute an SQL query, it must first be compiled into a byte-code | |
2476 ** program using one of these routines. | |
2477 ** | |
2478 ** The first argument, "db", is a [database connection] obtained from a | |
2479 ** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or | |
2480 ** [sqlite3_open16()]. The database connection must not have been closed. | |
2481 ** | |
2482 ** The second argument, "zSql", is the statement to be compiled, encoded | |
2483 ** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() | |
2484 ** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() | |
2485 ** use UTF-16. | |
2486 ** | |
2487 ** ^If the nByte argument is less than zero, then zSql is read up to the | |
2488 ** first zero terminator. ^If nByte is non-negative, then it is the maximum | |
2489 ** number of bytes read from zSql. ^When nByte is non-negative, the | |
2490 ** zSql string ends at either the first '\000' or '\u0000' character or | |
2491 ** the nByte-th byte, whichever comes first. If the caller knows | |
2492 ** that the supplied string is nul-terminated, then there is a small | |
2493 ** performance advantage to be gained by passing an nByte parameter that | |
2494 ** is equal to the number of bytes in the input string <i>including</i> | |
2495 ** the nul-terminator bytes. | |
2496 ** | |
2497 ** ^If pzTail is not NULL then *pzTail is made to point to the first byte | |
2498 ** past the end of the first SQL statement in zSql. These routines only | |
2499 ** compile the first statement in zSql, so *pzTail is left pointing to | |
2500 ** what remains uncompiled. | |
2501 ** | |
2502 ** ^*ppStmt is left pointing to a compiled [prepared statement] that can be | |
2503 ** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set | |
2504 ** to NULL. ^If the input text contains no SQL (if the input is an empty | |
2505 ** string or a comment) then *ppStmt is set to NULL. | |
2506 ** The calling procedure is responsible for deleting the compiled | |
2507 ** SQL statement using [sqlite3_finalize()] after it has finished with it. | |
2508 ** ppStmt may not be NULL. | |
2509 ** | |
2510 ** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; | |
2511 ** otherwise an [error code] is returned. | |
2512 ** | |
2513 ** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are | |
2514 ** recommended for all new programs. The two older interfaces are retained | |
2515 ** for backwards compatibility, but their use is discouraged. | |
2516 ** ^In the "v2" interfaces, the prepared statement | |
2517 ** that is returned (the [sqlite3_stmt] object) contains a copy of the | |
2518 ** original SQL text. This causes the [sqlite3_step()] interface to | |
2519 ** behave differently in three ways: | |
2520 ** | |
2521 ** <ol> | |
2522 ** <li> | |
2523 ** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it | |
2524 ** always used to do, [sqlite3_step()] will automatically recompile the SQL | |
2525 ** statement and try to run it again. ^If the schema has changed in | |
2526 ** a way that makes the statement no longer valid, [sqlite3_step()] will still | |
2527 ** return [SQLITE_SCHEMA]. But unlike the legacy behavior, [SQLITE_SCHEMA] is | |
2528 ** now a fatal error. Calling [sqlite3_prepare_v2()] again will not make the | |
2529 ** error go away. Note: use [sqlite3_errmsg()] to find the text | |
2530 ** of the parsing error that results in an [SQLITE_SCHEMA] return. | |
2531 ** </li> | |
2532 ** | |
2533 ** <li> | |
2534 ** ^When an error occurs, [sqlite3_step()] will return one of the detailed | |
2535 ** [error codes] or [extended error codes]. ^The legacy behavior was that | |
2536 ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code | |
2537 ** and the application would have to make a second call to [sqlite3_reset()] | |
2538 ** in order to find the underlying cause of the problem. With the "v2" prepare | |
2539 ** interfaces, the underlying reason for the error is returned immediately. | |
2540 ** </li> | |
2541 ** | |
2542 ** <li> | |
2543 ** ^If the value of a [parameter | host parameter] in the WHERE clause might | |
2544 ** change the query plan for a statement, then the statement may be | |
2545 ** automatically recompiled (as if there had been a schema change) on the first | |
2546 ** [sqlite3_step()] call following any change to the | |
2547 ** [sqlite3_bind_text | bindings] of the [parameter]. | |
2548 ** </li> | |
2549 ** </ol> | |
2550 */ | |
2551 SQLITE_API int sqlite3_prepare( | |
2552 sqlite3 *db, /* Database handle */ | |
2553 const char *zSql, /* SQL statement, UTF-8 encoded */ | |
2554 int nByte, /* Maximum length of zSql in bytes. */ | |
2555 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ | |
2556 const char **pzTail /* OUT: Pointer to unused portion of zSql */ | |
2557 ); | |
2558 SQLITE_API int sqlite3_prepare_v2( | |
2559 sqlite3 *db, /* Database handle */ | |
2560 const char *zSql, /* SQL statement, UTF-8 encoded */ | |
2561 int nByte, /* Maximum length of zSql in bytes. */ | |
2562 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ | |
2563 const char **pzTail /* OUT: Pointer to unused portion of zSql */ | |
2564 ); | |
2565 SQLITE_API int sqlite3_prepare16( | |
2566 sqlite3 *db, /* Database handle */ | |
2567 const void *zSql, /* SQL statement, UTF-16 encoded */ | |
2568 int nByte, /* Maximum length of zSql in bytes. */ | |
2569 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ | |
2570 const void **pzTail /* OUT: Pointer to unused portion of zSql */ | |
2571 ); | |
2572 SQLITE_API int sqlite3_prepare16_v2( | |
2573 sqlite3 *db, /* Database handle */ | |
2574 const void *zSql, /* SQL statement, UTF-16 encoded */ | |
2575 int nByte, /* Maximum length of zSql in bytes. */ | |
2576 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ | |
2577 const void **pzTail /* OUT: Pointer to unused portion of zSql */ | |
2578 ); | |
2579 | |
2580 /* | |
2581 ** CAPI3REF: Retrieving Statement SQL | |
2582 ** | |
2583 ** ^This interface can be used to retrieve a saved copy of the original | |
2584 ** SQL text used to create a [prepared statement] if that statement was | |
2585 ** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. | |
2586 */ | |
2587 SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt); | |
2588 | |
2589 /* | |
2590 ** CAPI3REF: Dynamically Typed Value Object | |
2591 ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} | |
2592 ** | |
2593 ** SQLite uses the sqlite3_value object to represent all values | |
2594 ** that can be stored in a database table. SQLite uses dynamic typing | |
2595 ** for the values it stores. ^Values stored in sqlite3_value objects | |
2596 ** can be integers, floating point values, strings, BLOBs, or NULL. | |
2597 ** | |
2598 ** An sqlite3_value object may be either "protected" or "unprotected". | |
2599 ** Some interfaces require a protected sqlite3_value. Other interfaces | |
2600 ** will accept either a protected or an unprotected sqlite3_value. | |
2601 ** Every interface that accepts sqlite3_value arguments specifies | |
2602 ** whether or not it requires a protected sqlite3_value. | |
2603 ** | |
2604 ** The terms "protected" and "unprotected" refer to whether or not | |
2605 ** a mutex is held. A internal mutex is held for a protected | |
2606 ** sqlite3_value object but no mutex is held for an unprotected | |
2607 ** sqlite3_value object. If SQLite is compiled to be single-threaded | |
2608 ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) | |
2609 ** or if SQLite is run in one of reduced mutex modes | |
2610 ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] | |
2611 ** then there is no distinction between protected and unprotected | |
2612 ** sqlite3_value objects and they can be used interchangeably. However, | |
2613 ** for maximum code portability it is recommended that applications | |
2614 ** still make the distinction between between protected and unprotected | |
2615 ** sqlite3_value objects even when not strictly required. | |
2616 ** | |
2617 ** ^The sqlite3_value objects that are passed as parameters into the | |
2618 ** implementation of [application-defined SQL functions] are protected. | |
2619 ** ^The sqlite3_value object returned by | |
2620 ** [sqlite3_column_value()] is unprotected. | |
2621 ** Unprotected sqlite3_value objects may only be used with | |
2622 ** [sqlite3_result_value()] and [sqlite3_bind_value()]. | |
2623 ** The [sqlite3_value_blob | sqlite3_value_type()] family of | |
2624 ** interfaces require protected sqlite3_value objects. | |
2625 */ | |
2626 typedef struct Mem sqlite3_value; | |
2627 | |
2628 /* | |
2629 ** CAPI3REF: SQL Function Context Object | |
2630 ** | |
2631 ** The context in which an SQL function executes is stored in an | |
2632 ** sqlite3_context object. ^A pointer to an sqlite3_context object | |
2633 ** is always first parameter to [application-defined SQL functions]. | |
2634 ** The application-defined SQL function implementation will pass this | |
2635 ** pointer through into calls to [sqlite3_result_int | sqlite3_result()], | |
2636 ** [sqlite3_aggregate_context()], [sqlite3_user_data()], | |
2637 ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], | |
2638 ** and/or [sqlite3_set_auxdata()]. | |
2639 */ | |
2640 typedef struct sqlite3_context sqlite3_context; | |
2641 | |
2642 /* | |
2643 ** CAPI3REF: Binding Values To Prepared Statements | |
2644 ** KEYWORDS: {host parameter} {host parameters} {host parameter name} | |
2645 ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} | |
2646 ** | |
2647 ** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, | |
2648 ** literals may be replaced by a [parameter] that matches one of following | |
2649 ** templates: | |
2650 ** | |
2651 ** <ul> | |
2652 ** <li> ? | |
2653 ** <li> ?NNN | |
2654 ** <li> :VVV | |
2655 ** <li> @VVV | |
2656 ** <li> $VVV | |
2657 ** </ul> | |
2658 ** | |
2659 ** In the templates above, NNN represents an integer literal, | |
2660 ** and VVV represents an alphanumeric identifer.)^ ^The values of these | |
2661 ** parameters (also called "host parameter names" or "SQL parameters") | |
2662 ** can be set using the sqlite3_bind_*() routines defined here. | |
2663 ** | |
2664 ** ^The first argument to the sqlite3_bind_*() routines is always | |
2665 ** a pointer to the [sqlite3_stmt] object returned from | |
2666 ** [sqlite3_prepare_v2()] or its variants. | |
2667 ** | |
2668 ** ^The second argument is the index of the SQL parameter to be set. | |
2669 ** ^The leftmost SQL parameter has an index of 1. ^When the same named | |
2670 ** SQL parameter is used more than once, second and subsequent | |
2671 ** occurrences have the same index as the first occurrence. | |
2672 ** ^The index for named parameters can be looked up using the | |
2673 ** [sqlite3_bind_parameter_index()] API if desired. ^The index | |
2674 ** for "?NNN" parameters is the value of NNN. | |
2675 ** ^The NNN value must be between 1 and the [sqlite3_limit()] | |
2676 ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). | |
2677 ** | |
2678 ** ^The third argument is the value to bind to the parameter. | |
2679 ** | |
2680 ** ^(In those routines that have a fourth argument, its value is the | |
2681 ** number of bytes in the parameter. To be clear: the value is the | |
2682 ** number of <u>bytes</u> in the value, not the number of characters.)^ | |
2683 ** ^If the fourth parameter is negative, the length of the string is | |
2684 ** the number of bytes up to the first zero terminator. | |
2685 ** | |
2686 ** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and | |
2687 ** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or | |
2688 ** string after SQLite has finished with it. ^If the fifth argument is | |
2689 ** the special value [SQLITE_STATIC], then SQLite assumes that the | |
2690 ** information is in static, unmanaged space and does not need to be freed. | |
2691 ** ^If the fifth argument has the value [SQLITE_TRANSIENT], then | |
2692 ** SQLite makes its own private copy of the data immediately, before | |
2693 ** the sqlite3_bind_*() routine returns. | |
2694 ** | |
2695 ** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that | |
2696 ** is filled with zeroes. ^A zeroblob uses a fixed amount of memory | |
2697 ** (just an integer to hold its size) while it is being processed. | |
2698 ** Zeroblobs are intended to serve as placeholders for BLOBs whose | |
2699 ** content is later written using | |
2700 ** [sqlite3_blob_open | incremental BLOB I/O] routines. | |
2701 ** ^A negative value for the zeroblob results in a zero-length BLOB. | |
2702 ** | |
2703 ** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer | |
2704 ** for the [prepared statement] or with a prepared statement for which | |
2705 ** [sqlite3_step()] has been called more recently than [sqlite3_reset()], | |
2706 ** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() | |
2707 ** routine is passed a [prepared statement] that has been finalized, the | |
2708 ** result is undefined and probably harmful. | |
2709 ** | |
2710 ** ^Bindings are not cleared by the [sqlite3_reset()] routine. | |
2711 ** ^Unbound parameters are interpreted as NULL. | |
2712 ** | |
2713 ** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an | |
2714 ** [error code] if anything goes wrong. | |
2715 ** ^[SQLITE_RANGE] is returned if the parameter | |
2716 ** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. | |
2717 ** | |
2718 ** See also: [sqlite3_bind_parameter_count()], | |
2719 ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. | |
2720 */ | |
2721 SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); | |
2722 SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double); | |
2723 SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int); | |
2724 SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); | |
2725 SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int); | |
2726 SQLITE_API int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*)); | |
2727 SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); | |
2728 SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); | |
2729 SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); | |
2730 | |
2731 /* | |
2732 ** CAPI3REF: Number Of SQL Parameters | |
2733 ** | |
2734 ** ^This routine can be used to find the number of [SQL parameters] | |
2735 ** in a [prepared statement]. SQL parameters are tokens of the | |
2736 ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as | |
2737 ** placeholders for values that are [sqlite3_bind_blob | bound] | |
2738 ** to the parameters at a later time. | |
2739 ** | |
2740 ** ^(This routine actually returns the index of the largest (rightmost) | |
2741 ** parameter. For all forms except ?NNN, this will correspond to the | |
2742 ** number of unique parameters. If parameters of the ?NNN form are used, | |
2743 ** there may be gaps in the list.)^ | |
2744 ** | |
2745 ** See also: [sqlite3_bind_blob|sqlite3_bind()], | |
2746 ** [sqlite3_bind_parameter_name()], and | |
2747 ** [sqlite3_bind_parameter_index()]. | |
2748 */ | |
2749 SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*); | |
2750 | |
2751 /* | |
2752 ** CAPI3REF: Name Of A Host Parameter | |
2753 ** | |
2754 ** ^The sqlite3_bind_parameter_name(P,N) interface returns | |
2755 ** the name of the N-th [SQL parameter] in the [prepared statement] P. | |
2756 ** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" | |
2757 ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" | |
2758 ** respectively. | |
2759 ** In other words, the initial ":" or "$" or "@" or "?" | |
2760 ** is included as part of the name.)^ | |
2761 ** ^Parameters of the form "?" without a following integer have no name | |
2762 ** and are referred to as "nameless" or "anonymous parameters". | |
2763 ** | |
2764 ** ^The first host parameter has an index of 1, not 0. | |
2765 ** | |
2766 ** ^If the value N is out of range or if the N-th parameter is | |
2767 ** nameless, then NULL is returned. ^The returned string is | |
2768 ** always in UTF-8 encoding even if the named parameter was | |
2769 ** originally specified as UTF-16 in [sqlite3_prepare16()] or | |
2770 ** [sqlite3_prepare16_v2()]. | |
2771 ** | |
2772 ** See also: [sqlite3_bind_blob|sqlite3_bind()], | |
2773 ** [sqlite3_bind_parameter_count()], and | |
2774 ** [sqlite3_bind_parameter_index()]. | |
2775 */ | |
2776 SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); | |
2777 | |
2778 /* | |
2779 ** CAPI3REF: Index Of A Parameter With A Given Name | |
2780 ** | |
2781 ** ^Return the index of an SQL parameter given its name. ^The | |
2782 ** index value returned is suitable for use as the second | |
2783 ** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero | |
2784 ** is returned if no matching parameter is found. ^The parameter | |
2785 ** name must be given in UTF-8 even if the original statement | |
2786 ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. | |
2787 ** | |
2788 ** See also: [sqlite3_bind_blob|sqlite3_bind()], | |
2789 ** [sqlite3_bind_parameter_count()], and | |
2790 ** [sqlite3_bind_parameter_index()]. | |
2791 */ | |
2792 SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); | |
2793 | |
2794 /* | |
2795 ** CAPI3REF: Reset All Bindings On A Prepared Statement | |
2796 ** | |
2797 ** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset | |
2798 ** the [sqlite3_bind_blob | bindings] on a [prepared statement]. | |
2799 ** ^Use this routine to reset all host parameters to NULL. | |
2800 */ | |
2801 SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*); | |
2802 | |
2803 /* | |
2804 ** CAPI3REF: Number Of Columns In A Result Set | |
2805 ** | |
2806 ** ^Return the number of columns in the result set returned by the | |
2807 ** [prepared statement]. ^This routine returns 0 if pStmt is an SQL | |
2808 ** statement that does not return data (for example an [UPDATE]). | |
2809 */ | |
2810 SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt); | |
2811 | |
2812 /* | |
2813 ** CAPI3REF: Column Names In A Result Set | |
2814 ** | |
2815 ** ^These routines return the name assigned to a particular column | |
2816 ** in the result set of a [SELECT] statement. ^The sqlite3_column_name() | |
2817 ** interface returns a pointer to a zero-terminated UTF-8 string | |
2818 ** and sqlite3_column_name16() returns a pointer to a zero-terminated | |
2819 ** UTF-16 string. ^The first parameter is the [prepared statement] | |
2820 ** that implements the [SELECT] statement. ^The second parameter is the | |
2821 ** column number. ^The leftmost column is number 0. | |
2822 ** | |
2823 ** ^The returned string pointer is valid until either the [prepared statement] | |
2824 ** is destroyed by [sqlite3_finalize()] or until the next call to | |
2825 ** sqlite3_column_name() or sqlite3_column_name16() on the same column. | |
2826 ** | |
2827 ** ^If sqlite3_malloc() fails during the processing of either routine | |
2828 ** (for example during a conversion from UTF-8 to UTF-16) then a | |
2829 ** NULL pointer is returned. | |
2830 ** | |
2831 ** ^The name of a result column is the value of the "AS" clause for | |
2832 ** that column, if there is an AS clause. If there is no AS clause | |
2833 ** then the name of the column is unspecified and may change from | |
2834 ** one release of SQLite to the next. | |
2835 */ | |
2836 SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N); | |
2837 SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N); | |
2838 | |
2839 /* | |
2840 ** CAPI3REF: Source Of Data In A Query Result | |
2841 ** | |
2842 ** ^These routines provide a means to determine the database, table, and | |
2843 ** table column that is the origin of a particular result column in | |
2844 ** [SELECT] statement. | |
2845 ** ^The name of the database or table or column can be returned as | |
2846 ** either a UTF-8 or UTF-16 string. ^The _database_ routines return | |
2847 ** the database name, the _table_ routines return the table name, and | |
2848 ** the origin_ routines return the column name. | |
2849 ** ^The returned string is valid until the [prepared statement] is destroyed | |
2850 ** using [sqlite3_finalize()] or until the same information is requested | |
2851 ** again in a different encoding. | |
2852 ** | |
2853 ** ^The names returned are the original un-aliased names of the | |
2854 ** database, table, and column. | |
2855 ** | |
2856 ** ^The first argument to these interfaces is a [prepared statement]. | |
2857 ** ^These functions return information about the Nth result column returned by | |
2858 ** the statement, where N is the second function argument. | |
2859 ** ^The left-most column is column 0 for these routines. | |
2860 ** | |
2861 ** ^If the Nth column returned by the statement is an expression or | |
2862 ** subquery and is not a column value, then all of these functions return | |
2863 ** NULL. ^These routine might also return NULL if a memory allocation error | |
2864 ** occurs. ^Otherwise, they return the name of the attached database, table, | |
2865 ** or column that query result column was extracted from. | |
2866 ** | |
2867 ** ^As with all other SQLite APIs, those whose names end with "16" return | |
2868 ** UTF-16 encoded strings and the other functions return UTF-8. | |
2869 ** | |
2870 ** ^These APIs are only available if the library was compiled with the | |
2871 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. | |
2872 ** | |
2873 ** If two or more threads call one or more of these routines against the same | |
2874 ** prepared statement and column at the same time then the results are | |
2875 ** undefined. | |
2876 ** | |
2877 ** If two or more threads call one or more | |
2878 ** [sqlite3_column_database_name | column metadata interfaces] | |
2879 ** for the same [prepared statement] and result column | |
2880 ** at the same time then the results are undefined. | |
2881 */ | |
2882 SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int); | |
2883 SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int); | |
2884 SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int); | |
2885 SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int); | |
2886 SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int); | |
2887 SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); | |
2888 | |
2889 /* | |
2890 ** CAPI3REF: Declared Datatype Of A Query Result | |
2891 ** | |
2892 ** ^(The first parameter is a [prepared statement]. | |
2893 ** If this statement is a [SELECT] statement and the Nth column of the | |
2894 ** returned result set of that [SELECT] is a table column (not an | |
2895 ** expression or subquery) then the declared type of the table | |
2896 ** column is returned.)^ ^If the Nth column of the result set is an | |
2897 ** expression or subquery, then a NULL pointer is returned. | |
2898 ** ^The returned string is always UTF-8 encoded. | |
2899 ** | |
2900 ** ^(For example, given the database schema: | |
2901 ** | |
2902 ** CREATE TABLE t1(c1 VARIANT); | |
2903 ** | |
2904 ** and the following statement to be compiled: | |
2905 ** | |
2906 ** SELECT c1 + 1, c1 FROM t1; | |
2907 ** | |
2908 ** this routine would return the string "VARIANT" for the second result | |
2909 ** column (i==1), and a NULL pointer for the first result column (i==0).)^ | |
2910 ** | |
2911 ** ^SQLite uses dynamic run-time typing. ^So just because a column | |
2912 ** is declared to contain a particular type does not mean that the | |
2913 ** data stored in that column is of the declared type. SQLite is | |
2914 ** strongly typed, but the typing is dynamic not static. ^Type | |
2915 ** is associated with individual values, not with the containers | |
2916 ** used to hold those values. | |
2917 */ | |
2918 SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int); | |
2919 SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int); | |
2920 | |
2921 /* | |
2922 ** CAPI3REF: Evaluate An SQL Statement | |
2923 ** | |
2924 ** After a [prepared statement] has been prepared using either | |
2925 ** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy | |
2926 ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function | |
2927 ** must be called one or more times to evaluate the statement. | |
2928 ** | |
2929 ** The details of the behavior of the sqlite3_step() interface depend | |
2930 ** on whether the statement was prepared using the newer "v2" interface | |
2931 ** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy | |
2932 ** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the | |
2933 ** new "v2" interface is recommended for new applications but the legacy | |
2934 ** interface will continue to be supported. | |
2935 ** | |
2936 ** ^In the legacy interface, the return value will be either [SQLITE_BUSY], | |
2937 ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. | |
2938 ** ^With the "v2" interface, any of the other [result codes] or | |
2939 ** [extended result codes] might be returned as well. | |
2940 ** | |
2941 ** ^[SQLITE_BUSY] means that the database engine was unable to acquire the | |
2942 ** database locks it needs to do its job. ^If the statement is a [COMMIT] | |
2943 ** or occurs outside of an explicit transaction, then you can retry the | |
2944 ** statement. If the statement is not a [COMMIT] and occurs within a | |
2945 ** explicit transaction then you should rollback the transaction before | |
2946 ** continuing. | |
2947 ** | |
2948 ** ^[SQLITE_DONE] means that the statement has finished executing | |
2949 ** successfully. sqlite3_step() should not be called again on this virtual | |
2950 ** machine without first calling [sqlite3_reset()] to reset the virtual | |
2951 ** machine back to its initial state. | |
2952 ** | |
2953 ** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] | |
2954 ** is returned each time a new row of data is ready for processing by the | |
2955 ** caller. The values may be accessed using the [column access functions]. | |
2956 ** sqlite3_step() is called again to retrieve the next row of data. | |
2957 ** | |
2958 ** ^[SQLITE_ERROR] means that a run-time error (such as a constraint | |
2959 ** violation) has occurred. sqlite3_step() should not be called again on | |
2960 ** the VM. More information may be found by calling [sqlite3_errmsg()]. | |
2961 ** ^With the legacy interface, a more specific error code (for example, | |
2962 ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) | |
2963 ** can be obtained by calling [sqlite3_reset()] on the | |
2964 ** [prepared statement]. ^In the "v2" interface, | |
2965 ** the more specific error code is returned directly by sqlite3_step(). | |
2966 ** | |
2967 ** [SQLITE_MISUSE] means that the this routine was called inappropriately. | |
2968 ** Perhaps it was called on a [prepared statement] that has | |
2969 ** already been [sqlite3_finalize | finalized] or on one that had | |
2970 ** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could | |
2971 ** be the case that the same database connection is being used by two or | |
2972 ** more threads at the same moment in time. | |
2973 ** | |
2974 ** For all versions of SQLite up to and including 3.6.23.1, it was required | |
2975 ** after sqlite3_step() returned anything other than [SQLITE_ROW] that | |
2976 ** [sqlite3_reset()] be called before any subsequent invocation of | |
2977 ** sqlite3_step(). Failure to invoke [sqlite3_reset()] in this way would | |
2978 ** result in an [SQLITE_MISUSE] return from sqlite3_step(). But after | |
2979 ** version 3.6.23.1, sqlite3_step() began calling [sqlite3_reset()] | |
2980 ** automatically in this circumstance rather than returning [SQLITE_MISUSE]. | |
2981 ** | |
2982 ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() | |
2983 ** API always returns a generic error code, [SQLITE_ERROR], following any | |
2984 ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call | |
2985 ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the | |
2986 ** specific [error codes] that better describes the error. | |
2987 ** We admit that this is a goofy design. The problem has been fixed | |
2988 ** with the "v2" interface. If you prepare all of your SQL statements | |
2989 ** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead | |
2990 ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, | |
2991 ** then the more specific [error codes] are returned directly | |
2992 ** by sqlite3_step(). The use of the "v2" interface is recommended. | |
2993 */ | |
2994 SQLITE_API int sqlite3_step(sqlite3_stmt*); | |
2995 | |
2996 /* | |
2997 ** CAPI3REF: Number of columns in a result set | |
2998 ** | |
2999 ** ^The sqlite3_data_count(P) the number of columns in the | |
3000 ** of the result set of [prepared statement] P. | |
3001 */ | |
3002 SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt); | |
3003 | |
3004 /* | |
3005 ** CAPI3REF: Fundamental Datatypes | |
3006 ** KEYWORDS: SQLITE_TEXT | |
3007 ** | |
3008 ** ^(Every value in SQLite has one of five fundamental datatypes: | |
3009 ** | |
3010 ** <ul> | |
3011 ** <li> 64-bit signed integer | |
3012 ** <li> 64-bit IEEE floating point number | |
3013 ** <li> string | |
3014 ** <li> BLOB | |
3015 ** <li> NULL | |
3016 ** </ul>)^ | |
3017 ** | |
3018 ** These constants are codes for each of those types. | |
3019 ** | |
3020 ** Note that the SQLITE_TEXT constant was also used in SQLite version 2 | |
3021 ** for a completely different meaning. Software that links against both | |
3022 ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not | |
3023 ** SQLITE_TEXT. | |
3024 */ | |
3025 #define SQLITE_INTEGER 1 | |
3026 #define SQLITE_FLOAT 2 | |
3027 #define SQLITE_BLOB 4 | |
3028 #define SQLITE_NULL 5 | |
3029 #ifdef SQLITE_TEXT | |
3030 # undef SQLITE_TEXT | |
3031 #else | |
3032 # define SQLITE_TEXT 3 | |
3033 #endif | |
3034 #define SQLITE3_TEXT 3 | |
3035 | |
3036 /* | |
3037 ** CAPI3REF: Result Values From A Query | |
3038 ** KEYWORDS: {column access functions} | |
3039 ** | |
3040 ** These routines form the "result set" interface. | |
3041 ** | |
3042 ** ^These routines return information about a single column of the current | |
3043 ** result row of a query. ^In every case the first argument is a pointer | |
3044 ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] | |
3045 ** that was returned from [sqlite3_prepare_v2()] or one of its variants) | |
3046 ** and the second argument is the index of the column for which information | |
3047 ** should be returned. ^The leftmost column of the result set has the index 0. | |
3048 ** ^The number of columns in the result can be determined using | |
3049 ** [sqlite3_column_count()]. | |
3050 ** | |
3051 ** If the SQL statement does not currently point to a valid row, or if the | |
3052 ** column index is out of range, the result is undefined. | |
3053 ** These routines may only be called when the most recent call to | |
3054 ** [sqlite3_step()] has returned [SQLITE_ROW] and neither | |
3055 ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. | |
3056 ** If any of these routines are called after [sqlite3_reset()] or | |
3057 ** [sqlite3_finalize()] or after [sqlite3_step()] has returned | |
3058 ** something other than [SQLITE_ROW], the results are undefined. | |
3059 ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] | |
3060 ** are called from a different thread while any of these routines | |
3061 ** are pending, then the results are undefined. | |
3062 ** | |
3063 ** ^The sqlite3_column_type() routine returns the | |
3064 ** [SQLITE_INTEGER | datatype code] for the initial data type | |
3065 ** of the result column. ^The returned value is one of [SQLITE_INTEGER], | |
3066 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value | |
3067 ** returned by sqlite3_column_type() is only meaningful if no type | |
3068 ** conversions have occurred as described below. After a type conversion, | |
3069 ** the value returned by sqlite3_column_type() is undefined. Future | |
3070 ** versions of SQLite may change the behavior of sqlite3_column_type() | |
3071 ** following a type conversion. | |
3072 ** | |
3073 ** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() | |
3074 ** routine returns the number of bytes in that BLOB or string. | |
3075 ** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts | |
3076 ** the string to UTF-8 and then returns the number of bytes. | |
3077 ** ^If the result is a numeric value then sqlite3_column_bytes() uses | |
3078 ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns | |
3079 ** the number of bytes in that string. | |
3080 ** ^The value returned does not include the zero terminator at the end | |
3081 ** of the string. ^For clarity: the value returned is the number of | |
3082 ** bytes in the string, not the number of characters. | |
3083 ** | |
3084 ** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), | |
3085 ** even empty strings, are always zero terminated. ^The return | |
3086 ** value from sqlite3_column_blob() for a zero-length BLOB is an arbitrary | |
3087 ** pointer, possibly even a NULL pointer. | |
3088 ** | |
3089 ** ^The sqlite3_column_bytes16() routine is similar to sqlite3_column_bytes() | |
3090 ** but leaves the result in UTF-16 in native byte order instead of UTF-8. | |
3091 ** ^The zero terminator is not included in this count. | |
3092 ** | |
3093 ** ^The object returned by [sqlite3_column_value()] is an | |
3094 ** [unprotected sqlite3_value] object. An unprotected sqlite3_value object | |
3095 ** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()]. | |
3096 ** If the [unprotected sqlite3_value] object returned by | |
3097 ** [sqlite3_column_value()] is used in any other way, including calls | |
3098 ** to routines like [sqlite3_value_int()], [sqlite3_value_text()], | |
3099 ** or [sqlite3_value_bytes()], then the behavior is undefined. | |
3100 ** | |
3101 ** These routines attempt to convert the value where appropriate. ^For | |
3102 ** example, if the internal representation is FLOAT and a text result | |
3103 ** is requested, [sqlite3_snprintf()] is used internally to perform the | |
3104 ** conversion automatically. ^(The following table details the conversions | |
3105 ** that are applied: | |
3106 ** | |
3107 ** <blockquote> | |
3108 ** <table border="1"> | |
3109 ** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion | |
3110 ** | |
3111 ** <tr><td> NULL <td> INTEGER <td> Result is 0 | |
3112 ** <tr><td> NULL <td> FLOAT <td> Result is 0.0 | |
3113 ** <tr><td> NULL <td> TEXT <td> Result is NULL pointer | |
3114 ** <tr><td> NULL <td> BLOB <td> Result is NULL pointer | |
3115 ** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float | |
3116 ** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer | |
3117 ** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT | |
3118 ** <tr><td> FLOAT <td> INTEGER <td> Convert from float to integer | |
3119 ** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float | |
3120 ** <tr><td> FLOAT <td> BLOB <td> Same as FLOAT->TEXT | |
3121 ** <tr><td> TEXT <td> INTEGER <td> Use atoi() | |
3122 ** <tr><td> TEXT <td> FLOAT <td> Use atof() | |
3123 ** <tr><td> TEXT <td> BLOB <td> No change | |
3124 ** <tr><td> BLOB <td> INTEGER <td> Convert to TEXT then use atoi() | |
3125 ** <tr><td> BLOB <td> FLOAT <td> Convert to TEXT then use atof() | |
3126 ** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed | |
3127 ** </table> | |
3128 ** </blockquote>)^ | |
3129 ** | |
3130 ** The table above makes reference to standard C library functions atoi() | |
3131 ** and atof(). SQLite does not really use these functions. It has its | |
3132 ** own equivalent internal routines. The atoi() and atof() names are | |
3133 ** used in the table for brevity and because they are familiar to most | |
3134 ** C programmers. | |
3135 ** | |
3136 ** ^Note that when type conversions occur, pointers returned by prior | |
3137 ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or | |
3138 ** sqlite3_column_text16() may be invalidated. | |
3139 ** ^(Type conversions and pointer invalidations might occur | |
3140 ** in the following cases: | |
3141 ** | |
3142 ** <ul> | |
3143 ** <li> The initial content is a BLOB and sqlite3_column_text() or | |
3144 ** sqlite3_column_text16() is called. A zero-terminator might | |
3145 ** need to be added to the string.</li> | |
3146 ** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or | |
3147 ** sqlite3_column_text16() is called. The content must be converted | |
3148 ** to UTF-16.</li> | |
3149 ** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or | |
3150 ** sqlite3_column_text() is called. The content must be converted | |
3151 ** to UTF-8.</li> | |
3152 ** </ul>)^ | |
3153 ** | |
3154 ** ^Conversions between UTF-16be and UTF-16le are always done in place and do | |
3155 ** not invalidate a prior pointer, though of course the content of the buffer | |
3156 ** that the prior pointer points to will have been modified. Other kinds | |
3157 ** of conversion are done in place when it is possible, but sometimes they | |
3158 ** are not possible and in those cases prior pointers are invalidated. | |
3159 ** | |
3160 ** ^(The safest and easiest to remember policy is to invoke these routines | |
3161 ** in one of the following ways: | |
3162 ** | |
3163 ** <ul> | |
3164 ** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> | |
3165 ** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> | |
3166 ** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> | |
3167 ** </ul>)^ | |
3168 ** | |
3169 ** In other words, you should call sqlite3_column_text(), | |
3170 ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result | |
3171 ** into the desired format, then invoke sqlite3_column_bytes() or | |
3172 ** sqlite3_column_bytes16() to find the size of the result. Do not mix calls | |
3173 ** to sqlite3_column_text() or sqlite3_column_blob() with calls to | |
3174 ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() | |
3175 ** with calls to sqlite3_column_bytes(). | |
3176 ** | |
3177 ** ^The pointers returned are valid until a type conversion occurs as | |
3178 ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or | |
3179 ** [sqlite3_finalize()] is called. ^The memory space used to hold strings | |
3180 ** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned | |
3181 ** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into | |
3182 ** [sqlite3_free()]. | |
3183 ** | |
3184 ** ^(If a memory allocation error occurs during the evaluation of any | |
3185 ** of these routines, a default value is returned. The default value | |
3186 ** is either the integer 0, the floating point number 0.0, or a NULL | |
3187 ** pointer. Subsequent calls to [sqlite3_errcode()] will return | |
3188 ** [SQLITE_NOMEM].)^ | |
3189 */ | |
3190 SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); | |
3191 SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol); | |
3192 SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); | |
3193 SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol); | |
3194 SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol); | |
3195 SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); | |
3196 SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); | |
3197 SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); | |
3198 SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol); | |
3199 SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); | |
3200 | |
3201 /* | |
3202 ** CAPI3REF: Destroy A Prepared Statement Object | |
3203 ** | |
3204 ** ^The sqlite3_finalize() function is called to delete a [prepared statement]. | |
3205 ** ^If the statement was executed successfully or not executed at all, then | |
3206 ** SQLITE_OK is returned. ^If execution of the statement failed then an | |
3207 ** [error code] or [extended error code] is returned. | |
3208 ** | |
3209 ** ^This routine can be called at any point during the execution of the | |
3210 ** [prepared statement]. ^If the virtual machine has not | |
3211 ** completed execution when this routine is called, that is like | |
3212 ** encountering an error or an [sqlite3_interrupt | interrupt]. | |
3213 ** ^Incomplete updates may be rolled back and transactions canceled, | |
3214 ** depending on the circumstances, and the | |
3215 ** [error code] returned will be [SQLITE_ABORT]. | |
3216 */ | |
3217 SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt); | |
3218 | |
3219 /* | |
3220 ** CAPI3REF: Reset A Prepared Statement Object | |
3221 ** | |
3222 ** The sqlite3_reset() function is called to reset a [prepared statement] | |
3223 ** object back to its initial state, ready to be re-executed. | |
3224 ** ^Any SQL statement variables that had values bound to them using | |
3225 ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. | |
3226 ** Use [sqlite3_clear_bindings()] to reset the bindings. | |
3227 ** | |
3228 ** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S | |
3229 ** back to the beginning of its program. | |
3230 ** | |
3231 ** ^If the most recent call to [sqlite3_step(S)] for the | |
3232 ** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], | |
3233 ** or if [sqlite3_step(S)] has never before been called on S, | |
3234 ** then [sqlite3_reset(S)] returns [SQLITE_OK]. | |
3235 ** | |
3236 ** ^If the most recent call to [sqlite3_step(S)] for the | |
3237 ** [prepared statement] S indicated an error, then | |
3238 ** [sqlite3_reset(S)] returns an appropriate [error code]. | |
3239 ** | |
3240 ** ^The [sqlite3_reset(S)] interface does not change the values | |
3241 ** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. | |
3242 */ | |
3243 SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt); | |
3244 | |
3245 /* | |
3246 ** CAPI3REF: Create Or Redefine SQL Functions | |
3247 ** KEYWORDS: {function creation routines} | |
3248 ** KEYWORDS: {application-defined SQL function} | |
3249 ** KEYWORDS: {application-defined SQL functions} | |
3250 ** | |
3251 ** ^These two functions (collectively known as "function creation routines") | |
3252 ** are used to add SQL functions or aggregates or to redefine the behavior | |
3253 ** of existing SQL functions or aggregates. The only difference between the | |
3254 ** two is that the second parameter, the name of the (scalar) function or | |
3255 ** aggregate, is encoded in UTF-8 for sqlite3_create_function() and UTF-16 | |
3256 ** for sqlite3_create_function16(). | |
3257 ** | |
3258 ** ^The first parameter is the [database connection] to which the SQL | |
3259 ** function is to be added. ^If an application uses more than one database | |
3260 ** connection then application-defined SQL functions must be added | |
3261 ** to each database connection separately. | |
3262 ** | |
3263 ** The second parameter is the name of the SQL function to be created or | |
3264 ** redefined. ^The length of the name is limited to 255 bytes, exclusive of | |
3265 ** the zero-terminator. Note that the name length limit is in bytes, not | |
3266 ** characters. ^Any attempt to create a function with a longer name | |
3267 ** will result in [SQLITE_ERROR] being returned. | |
3268 ** | |
3269 ** ^The third parameter (nArg) | |
3270 ** is the number of arguments that the SQL function or | |
3271 ** aggregate takes. ^If this parameter is -1, then the SQL function or | |
3272 ** aggregate may take any number of arguments between 0 and the limit | |
3273 ** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third | |
3274 ** parameter is less than -1 or greater than 127 then the behavior is | |
3275 ** undefined. | |
3276 ** | |
3277 ** The fourth parameter, eTextRep, specifies what | |
3278 ** [SQLITE_UTF8 | text encoding] this SQL function prefers for | |
3279 ** its parameters. Any SQL function implementation should be able to work | |
3280 ** work with UTF-8, UTF-16le, or UTF-16be. But some implementations may be | |
3281 ** more efficient with one encoding than another. ^An application may | |
3282 ** invoke sqlite3_create_function() or sqlite3_create_function16() multiple | |
3283 ** times with the same function but with different values of eTextRep. | |
3284 ** ^When multiple implementations of the same function are available, SQLite | |
3285 ** will pick the one that involves the least amount of data conversion. | |
3286 ** If there is only a single implementation which does not care what text | |
3287 ** encoding is used, then the fourth argument should be [SQLITE_ANY]. | |
3288 ** | |
3289 ** ^(The fifth parameter is an arbitrary pointer. The implementation of the | |
3290 ** function can gain access to this pointer using [sqlite3_user_data()].)^ | |
3291 ** | |
3292 ** The seventh, eighth and ninth parameters, xFunc, xStep and xFinal, are | |
3293 ** pointers to C-language functions that implement the SQL function or | |
3294 ** aggregate. ^A scalar SQL function requires an implementation of the xFunc | |
3295 ** callback only; NULL pointers should be passed as the xStep and xFinal | |
3296 ** parameters. ^An aggregate SQL function requires an implementation of xStep | |
3297 ** and xFinal and NULL should be passed for xFunc. ^To delete an existing | |
3298 ** SQL function or aggregate, pass NULL for all three function callbacks. | |
3299 ** | |
3300 ** ^It is permitted to register multiple implementations of the same | |
3301 ** functions with the same name but with either differing numbers of | |
3302 ** arguments or differing preferred text encodings. ^SQLite will use | |
3303 ** the implementation that most closely matches the way in which the | |
3304 ** SQL function is used. ^A function implementation with a non-negative | |
3305 ** nArg parameter is a better match than a function implementation with | |
3306 ** a negative nArg. ^A function where the preferred text encoding | |
3307 ** matches the database encoding is a better | |
3308 ** match than a function where the encoding is different. | |
3309 ** ^A function where the encoding difference is between UTF16le and UTF16be | |
3310 ** is a closer match than a function where the encoding difference is | |
3311 ** between UTF8 and UTF16. | |
3312 ** | |
3313 ** ^Built-in functions may be overloaded by new application-defined functions. | |
3314 ** ^The first application-defined function with a given name overrides all | |
3315 ** built-in functions in the same [database connection] with the same name. | |
3316 ** ^Subsequent application-defined functions of the same name only override | |
3317 ** prior application-defined functions that are an exact match for the | |
3318 ** number of parameters and preferred encoding. | |
3319 ** | |
3320 ** ^An application-defined function is permitted to call other | |
3321 ** SQLite interfaces. However, such calls must not | |
3322 ** close the database connection nor finalize or reset the prepared | |
3323 ** statement in which the function is running. | |
3324 */ | |
3325 SQLITE_API int sqlite3_create_function( | |
3326 sqlite3 *db, | |
3327 const char *zFunctionName, | |
3328 int nArg, | |
3329 int eTextRep, | |
3330 void *pApp, | |
3331 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), | |
3332 void (*xStep)(sqlite3_context*,int,sqlite3_value**), | |
3333 void (*xFinal)(sqlite3_context*) | |
3334 ); | |
3335 SQLITE_API int sqlite3_create_function16( | |
3336 sqlite3 *db, | |
3337 const void *zFunctionName, | |
3338 int nArg, | |
3339 int eTextRep, | |
3340 void *pApp, | |
3341 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), | |
3342 void (*xStep)(sqlite3_context*,int,sqlite3_value**), | |
3343 void (*xFinal)(sqlite3_context*) | |
3344 ); | |
3345 | |
3346 /* | |
3347 ** CAPI3REF: Text Encodings | |
3348 ** | |
3349 ** These constant define integer codes that represent the various | |
3350 ** text encodings supported by SQLite. | |
3351 */ | |
3352 #define SQLITE_UTF8 1 | |
3353 #define SQLITE_UTF16LE 2 | |
3354 #define SQLITE_UTF16BE 3 | |
3355 #define SQLITE_UTF16 4 /* Use native byte order */ | |
3356 #define SQLITE_ANY 5 /* sqlite3_create_function only */ | |
3357 #define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ | |
3358 | |
3359 /* | |
3360 ** CAPI3REF: Deprecated Functions | |
3361 ** DEPRECATED | |
3362 ** | |
3363 ** These functions are [deprecated]. In order to maintain | |
3364 ** backwards compatibility with older code, these functions continue | |
3365 ** to be supported. However, new applications should avoid | |
3366 ** the use of these functions. To help encourage people to avoid | |
3367 ** using these functions, we are not going to tell you what they do. | |
3368 */ | |
3369 #ifndef SQLITE_OMIT_DEPRECATED | |
3370 SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); | |
3371 SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); | |
3372 SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); | |
3373 SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void); | |
3374 SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); | |
3375 SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64); | |
3376 #endif | |
3377 | |
3378 /* | |
3379 ** CAPI3REF: Obtaining SQL Function Parameter Values | |
3380 ** | |
3381 ** The C-language implementation of SQL functions and aggregates uses | |
3382 ** this set of interface routines to access the parameter values on | |
3383 ** the function or aggregate. | |
3384 ** | |
3385 ** The xFunc (for scalar functions) or xStep (for aggregates) parameters | |
3386 ** to [sqlite3_create_function()] and [sqlite3_create_function16()] | |
3387 ** define callbacks that implement the SQL functions and aggregates. | |
3388 ** The 4th parameter to these callbacks is an array of pointers to | |
3389 ** [protected sqlite3_value] objects. There is one [sqlite3_value] object for | |
3390 ** each parameter to the SQL function. These routines are used to | |
3391 ** extract values from the [sqlite3_value] objects. | |
3392 ** | |
3393 ** These routines work only with [protected sqlite3_value] objects. | |
3394 ** Any attempt to use these routines on an [unprotected sqlite3_value] | |
3395 ** object results in undefined behavior. | |
3396 ** | |
3397 ** ^These routines work just like the corresponding [column access functions] | |
3398 ** except that these routines take a single [protected sqlite3_value] object | |
3399 ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. | |
3400 ** | |
3401 ** ^The sqlite3_value_text16() interface extracts a UTF-16 string | |
3402 ** in the native byte-order of the host machine. ^The | |
3403 ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces | |
3404 ** extract UTF-16 strings as big-endian and little-endian respectively. | |
3405 ** | |
3406 ** ^(The sqlite3_value_numeric_type() interface attempts to apply | |
3407 ** numeric affinity to the value. This means that an attempt is | |
3408 ** made to convert the value to an integer or floating point. If | |
3409 ** such a conversion is possible without loss of information (in other | |
3410 ** words, if the value is a string that looks like a number) | |
3411 ** then the conversion is performed. Otherwise no conversion occurs. | |
3412 ** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ | |
3413 ** | |
3414 ** Please pay particular attention to the fact that the pointer returned | |
3415 ** from [sqlite3_value_blob()], [sqlite3_value_text()], or | |
3416 ** [sqlite3_value_text16()] can be invalidated by a subsequent call to | |
3417 ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], | |
3418 ** or [sqlite3_value_text16()]. | |
3419 ** | |
3420 ** These routines must be called from the same thread as | |
3421 ** the SQL function that supplied the [sqlite3_value*] parameters. | |
3422 */ | |
3423 SQLITE_API const void *sqlite3_value_blob(sqlite3_value*); | |
3424 SQLITE_API int sqlite3_value_bytes(sqlite3_value*); | |
3425 SQLITE_API int sqlite3_value_bytes16(sqlite3_value*); | |
3426 SQLITE_API double sqlite3_value_double(sqlite3_value*); | |
3427 SQLITE_API int sqlite3_value_int(sqlite3_value*); | |
3428 SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*); | |
3429 SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*); | |
3430 SQLITE_API const void *sqlite3_value_text16(sqlite3_value*); | |
3431 SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*); | |
3432 SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*); | |
3433 SQLITE_API int sqlite3_value_type(sqlite3_value*); | |
3434 SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*); | |
3435 | |
3436 /* | |
3437 ** CAPI3REF: Obtain Aggregate Function Context | |
3438 ** | |
3439 ** Implementions of aggregate SQL functions use this | |
3440 ** routine to allocate memory for storing their state. | |
3441 ** | |
3442 ** ^The first time the sqlite3_aggregate_context(C,N) routine is called | |
3443 ** for a particular aggregate function, SQLite | |
3444 ** allocates N of memory, zeroes out that memory, and returns a pointer | |
3445 ** to the new memory. ^On second and subsequent calls to | |
3446 ** sqlite3_aggregate_context() for the same aggregate function instance, | |
3447 ** the same buffer is returned. Sqlite3_aggregate_context() is normally | |
3448 ** called once for each invocation of the xStep callback and then one | |
3449 ** last time when the xFinal callback is invoked. ^(When no rows match | |
3450 ** an aggregate query, the xStep() callback of the aggregate function | |
3451 ** implementation is never called and xFinal() is called exactly once. | |
3452 ** In those cases, sqlite3_aggregate_context() might be called for the | |
3453 ** first time from within xFinal().)^ | |
3454 ** | |
3455 ** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer if N is | |
3456 ** less than or equal to zero or if a memory allocate error occurs. | |
3457 ** | |
3458 ** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is | |
3459 ** determined by the N parameter on first successful call. Changing the | |
3460 ** value of N in subsequent call to sqlite3_aggregate_context() within | |
3461 ** the same aggregate function instance will not resize the memory | |
3462 ** allocation.)^ | |
3463 ** | |
3464 ** ^SQLite automatically frees the memory allocated by | |
3465 ** sqlite3_aggregate_context() when the aggregate query concludes. | |
3466 ** | |
3467 ** The first parameter must be a copy of the | |
3468 ** [sqlite3_context | SQL function context] that is the first parameter | |
3469 ** to the xStep or xFinal callback routine that implements the aggregate | |
3470 ** function. | |
3471 ** | |
3472 ** This routine must be called from the same thread in which | |
3473 ** the aggregate SQL function is running. | |
3474 */ | |
3475 SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); | |
3476 | |
3477 /* | |
3478 ** CAPI3REF: User Data For Functions | |
3479 ** | |
3480 ** ^The sqlite3_user_data() interface returns a copy of | |
3481 ** the pointer that was the pUserData parameter (the 5th parameter) | |
3482 ** of the [sqlite3_create_function()] | |
3483 ** and [sqlite3_create_function16()] routines that originally | |
3484 ** registered the application defined function. | |
3485 ** | |
3486 ** This routine must be called from the same thread in which | |
3487 ** the application-defined function is running. | |
3488 */ | |
3489 SQLITE_API void *sqlite3_user_data(sqlite3_context*); | |
3490 | |
3491 /* | |
3492 ** CAPI3REF: Database Connection For Functions | |
3493 ** | |
3494 ** ^The sqlite3_context_db_handle() interface returns a copy of | |
3495 ** the pointer to the [database connection] (the 1st parameter) | |
3496 ** of the [sqlite3_create_function()] | |
3497 ** and [sqlite3_create_function16()] routines that originally | |
3498 ** registered the application defined function. | |
3499 */ | |
3500 SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*); | |
3501 | |
3502 /* | |
3503 ** CAPI3REF: Function Auxiliary Data | |
3504 ** | |
3505 ** The following two functions may be used by scalar SQL functions to | |
3506 ** associate metadata with argument values. If the same value is passed to | |
3507 ** multiple invocations of the same SQL function during query execution, under | |
3508 ** some circumstances the associated metadata may be preserved. This may | |
3509 ** be used, for example, to add a regular-expression matching scalar | |
3510 ** function. The compiled version of the regular expression is stored as | |
3511 ** metadata associated with the SQL value passed as the regular expression | |
3512 ** pattern. The compiled regular expression can be reused on multiple | |
3513 ** invocations of the same function so that the original pattern string | |
3514 ** does not need to be recompiled on each invocation. | |
3515 ** | |
3516 ** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata | |
3517 ** associated by the sqlite3_set_auxdata() function with the Nth argument | |
3518 ** value to the application-defined function. ^If no metadata has been ever | |
3519 ** been set for the Nth argument of the function, or if the corresponding | |
3520 ** function parameter has changed since the meta-data was set, | |
3521 ** then sqlite3_get_auxdata() returns a NULL pointer. | |
3522 ** | |
3523 ** ^The sqlite3_set_auxdata() interface saves the metadata | |
3524 ** pointed to by its 3rd parameter as the metadata for the N-th | |
3525 ** argument of the application-defined function. Subsequent | |
3526 ** calls to sqlite3_get_auxdata() might return this data, if it has | |
3527 ** not been destroyed. | |
3528 ** ^If it is not NULL, SQLite will invoke the destructor | |
3529 ** function given by the 4th parameter to sqlite3_set_auxdata() on | |
3530 ** the metadata when the corresponding function parameter changes | |
3531 ** or when the SQL statement completes, whichever comes first. | |
3532 ** | |
3533 ** SQLite is free to call the destructor and drop metadata on any | |
3534 ** parameter of any function at any time. ^The only guarantee is that | |
3535 ** the destructor will be called before the metadata is dropped. | |
3536 ** | |
3537 ** ^(In practice, metadata is preserved between function calls for | |
3538 ** expressions that are constant at compile time. This includes literal | |
3539 ** values and [parameters].)^ | |
3540 ** | |
3541 ** These routines must be called from the same thread in which | |
3542 ** the SQL function is running. | |
3543 */ | |
3544 SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N); | |
3545 SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); | |
3546 | |
3547 | |
3548 /* | |
3549 ** CAPI3REF: Constants Defining Special Destructor Behavior | |
3550 ** | |
3551 ** These are special values for the destructor that is passed in as the | |
3552 ** final argument to routines like [sqlite3_result_blob()]. ^If the destructor | |
3553 ** argument is SQLITE_STATIC, it means that the content pointer is constant | |
3554 ** and will never change. It does not need to be destroyed. ^The | |
3555 ** SQLITE_TRANSIENT value means that the content will likely change in | |
3556 ** the near future and that SQLite should make its own private copy of | |
3557 ** the content before returning. | |
3558 ** | |
3559 ** The typedef is necessary to work around problems in certain | |
3560 ** C++ compilers. See ticket #2191. | |
3561 */ | |
3562 typedef void (*sqlite3_destructor_type)(void*); | |
3563 #define SQLITE_STATIC ((sqlite3_destructor_type)0) | |
3564 #define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) | |
3565 | |
3566 /* | |
3567 ** CAPI3REF: Setting The Result Of An SQL Function | |
3568 ** | |
3569 ** These routines are used by the xFunc or xFinal callbacks that | |
3570 ** implement SQL functions and aggregates. See | |
3571 ** [sqlite3_create_function()] and [sqlite3_create_function16()] | |
3572 ** for additional information. | |
3573 ** | |
3574 ** These functions work very much like the [parameter binding] family of | |
3575 ** functions used to bind values to host parameters in prepared statements. | |
3576 ** Refer to the [SQL parameter] documentation for additional information. | |
3577 ** | |
3578 ** ^The sqlite3_result_blob() interface sets the result from | |
3579 ** an application-defined function to be the BLOB whose content is pointed | |
3580 ** to by the second parameter and which is N bytes long where N is the | |
3581 ** third parameter. | |
3582 ** | |
3583 ** ^The sqlite3_result_zeroblob() interfaces set the result of | |
3584 ** the application-defined function to be a BLOB containing all zero | |
3585 ** bytes and N bytes in size, where N is the value of the 2nd parameter. | |
3586 ** | |
3587 ** ^The sqlite3_result_double() interface sets the result from | |
3588 ** an application-defined function to be a floating point value specified | |
3589 ** by its 2nd argument. | |
3590 ** | |
3591 ** ^The sqlite3_result_error() and sqlite3_result_error16() functions | |
3592 ** cause the implemented SQL function to throw an exception. | |
3593 ** ^SQLite uses the string pointed to by the | |
3594 ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() | |
3595 ** as the text of an error message. ^SQLite interprets the error | |
3596 ** message string from sqlite3_result_error() as UTF-8. ^SQLite | |
3597 ** interprets the string from sqlite3_result_error16() as UTF-16 in native | |
3598 ** byte order. ^If the third parameter to sqlite3_result_error() | |
3599 ** or sqlite3_result_error16() is negative then SQLite takes as the error | |
3600 ** message all text up through the first zero character. | |
3601 ** ^If the third parameter to sqlite3_result_error() or | |
3602 ** sqlite3_result_error16() is non-negative then SQLite takes that many | |
3603 ** bytes (not characters) from the 2nd parameter as the error message. | |
3604 ** ^The sqlite3_result_error() and sqlite3_result_error16() | |
3605 ** routines make a private copy of the error message text before | |
3606 ** they return. Hence, the calling function can deallocate or | |
3607 ** modify the text after they return without harm. | |
3608 ** ^The sqlite3_result_error_code() function changes the error code | |
3609 ** returned by SQLite as a result of an error in a function. ^By default, | |
3610 ** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() | |
3611 ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. | |
3612 ** | |
3613 ** ^The sqlite3_result_toobig() interface causes SQLite to throw an error | |
3614 ** indicating that a string or BLOB is too long to represent. | |
3615 ** | |
3616 ** ^The sqlite3_result_nomem() interface causes SQLite to throw an error | |
3617 ** indicating that a memory allocation failed. | |
3618 ** | |
3619 ** ^The sqlite3_result_int() interface sets the return value | |
3620 ** of the application-defined function to be the 32-bit signed integer | |
3621 ** value given in the 2nd argument. | |
3622 ** ^The sqlite3_result_int64() interface sets the return value | |
3623 ** of the application-defined function to be the 64-bit signed integer | |
3624 ** value given in the 2nd argument. | |
3625 ** | |
3626 ** ^The sqlite3_result_null() interface sets the return value | |
3627 ** of the application-defined function to be NULL. | |
3628 ** | |
3629 ** ^The sqlite3_result_text(), sqlite3_result_text16(), | |
3630 ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces | |
3631 ** set the return value of the application-defined function to be | |
3632 ** a text string which is represented as UTF-8, UTF-16 native byte order, | |
3633 ** UTF-16 little endian, or UTF-16 big endian, respectively. | |
3634 ** ^SQLite takes the text result from the application from | |
3635 ** the 2nd parameter of the sqlite3_result_text* interfaces. | |
3636 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces | |
3637 ** is negative, then SQLite takes result text from the 2nd parameter | |
3638 ** through the first zero character. | |
3639 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces | |
3640 ** is non-negative, then as many bytes (not characters) of the text | |
3641 ** pointed to by the 2nd parameter are taken as the application-defined | |
3642 ** function result. | |
3643 ** ^If the 4th parameter to the sqlite3_result_text* interfaces | |
3644 ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that | |
3645 ** function as the destructor on the text or BLOB result when it has | |
3646 ** finished using that result. | |
3647 ** ^If the 4th parameter to the sqlite3_result_text* interfaces or to | |
3648 ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite | |
3649 ** assumes that the text or BLOB result is in constant space and does not | |
3650 ** copy the content of the parameter nor call a destructor on the content | |
3651 ** when it has finished using that result. | |
3652 ** ^If the 4th parameter to the sqlite3_result_text* interfaces | |
3653 ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT | |
3654 ** then SQLite makes a copy of the result into space obtained from | |
3655 ** from [sqlite3_malloc()] before it returns. | |
3656 ** | |
3657 ** ^The sqlite3_result_value() interface sets the result of | |
3658 ** the application-defined function to be a copy the | |
3659 ** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The | |
3660 ** sqlite3_result_value() interface makes a copy of the [sqlite3_value] | |
3661 ** so that the [sqlite3_value] specified in the parameter may change or | |
3662 ** be deallocated after sqlite3_result_value() returns without harm. | |
3663 ** ^A [protected sqlite3_value] object may always be used where an | |
3664 ** [unprotected sqlite3_value] object is required, so either | |
3665 ** kind of [sqlite3_value] object can be used with this interface. | |
3666 ** | |
3667 ** If these routines are called from within the different thread | |
3668 ** than the one containing the application-defined function that received | |
3669 ** the [sqlite3_context] pointer, the results are undefined. | |
3670 */ | |
3671 SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); | |
3672 SQLITE_API void sqlite3_result_double(sqlite3_context*, double); | |
3673 SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int); | |
3674 SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int); | |
3675 SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*); | |
3676 SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*); | |
3677 SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int); | |
3678 SQLITE_API void sqlite3_result_int(sqlite3_context*, int); | |
3679 SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); | |
3680 SQLITE_API void sqlite3_result_null(sqlite3_context*); | |
3681 SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); | |
3682 SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); | |
3683 SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); | |
3684 SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); | |
3685 SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*); | |
3686 SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n); | |
3687 | |
3688 /* | |
3689 ** CAPI3REF: Define New Collating Sequences | |
3690 ** | |
3691 ** These functions are used to add new collation sequences to the | |
3692 ** [database connection] specified as the first argument. | |
3693 ** | |
3694 ** ^The name of the new collation sequence is specified as a UTF-8 string | |
3695 ** for sqlite3_create_collation() and sqlite3_create_collation_v2() | |
3696 ** and a UTF-16 string for sqlite3_create_collation16(). ^In all cases | |
3697 ** the name is passed as the second function argument. | |
3698 ** | |
3699 ** ^The third argument may be one of the constants [SQLITE_UTF8], | |
3700 ** [SQLITE_UTF16LE], or [SQLITE_UTF16BE], indicating that the user-supplied | |
3701 ** routine expects to be passed pointers to strings encoded using UTF-8, | |
3702 ** UTF-16 little-endian, or UTF-16 big-endian, respectively. ^The | |
3703 ** third argument might also be [SQLITE_UTF16] to indicate that the routine | |
3704 ** expects pointers to be UTF-16 strings in the native byte order, or the | |
3705 ** argument can be [SQLITE_UTF16_ALIGNED] if the | |
3706 ** the routine expects pointers to 16-bit word aligned strings | |
3707 ** of UTF-16 in the native byte order. | |
3708 ** | |
3709 ** A pointer to the user supplied routine must be passed as the fifth | |
3710 ** argument. ^If it is NULL, this is the same as deleting the collation | |
3711 ** sequence (so that SQLite cannot call it anymore). | |
3712 ** ^Each time the application supplied function is invoked, it is passed | |
3713 ** as its first parameter a copy of the void* passed as the fourth argument | |
3714 ** to sqlite3_create_collation() or sqlite3_create_collation16(). | |
3715 ** | |
3716 ** ^The remaining arguments to the application-supplied routine are two strings, | |
3717 ** each represented by a (length, data) pair and encoded in the encoding | |
3718 ** that was passed as the third argument when the collation sequence was | |
3719 ** registered. The application defined collation routine should | |
3720 ** return negative, zero or positive if the first string is less than, | |
3721 ** equal to, or greater than the second string. i.e. (STRING1 - STRING2). | |
3722 ** | |
3723 ** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() | |
3724 ** except that it takes an extra argument which is a destructor for | |
3725 ** the collation. ^The destructor is called when the collation is | |
3726 ** destroyed and is passed a copy of the fourth parameter void* pointer | |
3727 ** of the sqlite3_create_collation_v2(). | |
3728 ** ^Collations are destroyed when they are overridden by later calls to the | |
3729 ** collation creation functions or when the [database connection] is closed | |
3730 ** using [sqlite3_close()]. | |
3731 ** | |
3732 ** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. | |
3733 */ | |
3734 SQLITE_API int sqlite3_create_collation( | |
3735 sqlite3*, | |
3736 const char *zName, | |
3737 int eTextRep, | |
3738 void*, | |
3739 int(*xCompare)(void*,int,const void*,int,const void*) | |
3740 ); | |
3741 SQLITE_API int sqlite3_create_collation_v2( | |
3742 sqlite3*, | |
3743 const char *zName, | |
3744 int eTextRep, | |
3745 void*, | |
3746 int(*xCompare)(void*,int,const void*,int,const void*), | |
3747 void(*xDestroy)(void*) | |
3748 ); | |
3749 SQLITE_API int sqlite3_create_collation16( | |
3750 sqlite3*, | |
3751 const void *zName, | |
3752 int eTextRep, | |
3753 void*, | |
3754 int(*xCompare)(void*,int,const void*,int,const void*) | |
3755 ); | |
3756 | |
3757 /* | |
3758 ** CAPI3REF: Collation Needed Callbacks | |
3759 ** | |
3760 ** ^To avoid having to register all collation sequences before a database | |
3761 ** can be used, a single callback function may be registered with the | |
3762 ** [database connection] to be invoked whenever an undefined collation | |
3763 ** sequence is required. | |
3764 ** | |
3765 ** ^If the function is registered using the sqlite3_collation_needed() API, | |
3766 ** then it is passed the names of undefined collation sequences as strings | |
3767 ** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, | |
3768 ** the names are passed as UTF-16 in machine native byte order. | |
3769 ** ^A call to either function replaces the existing collation-needed callback. | |
3770 ** | |
3771 ** ^(When the callback is invoked, the first argument passed is a copy | |
3772 ** of the second argument to sqlite3_collation_needed() or | |
3773 ** sqlite3_collation_needed16(). The second argument is the database | |
3774 ** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], | |
3775 ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation | |
3776 ** sequence function required. The fourth parameter is the name of the | |
3777 ** required collation sequence.)^ | |
3778 ** | |
3779 ** The callback function should register the desired collation using | |
3780 ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or | |
3781 ** [sqlite3_create_collation_v2()]. | |
3782 */ | |
3783 SQLITE_API int sqlite3_collation_needed( | |
3784 sqlite3*, | |
3785 void*, | |
3786 void(*)(void*,sqlite3*,int eTextRep,const char*) | |
3787 ); | |
3788 SQLITE_API int sqlite3_collation_needed16( | |
3789 sqlite3*, | |
3790 void*, | |
3791 void(*)(void*,sqlite3*,int eTextRep,const void*) | |
3792 ); | |
3793 | |
3794 #ifdef SQLITE_HAS_CODEC | |
3795 /* | |
3796 ** Specify the key for an encrypted database. This routine should be | |
3797 ** called right after sqlite3_open(). | |
3798 ** | |
3799 ** The code to implement this API is not available in the public release | |
3800 ** of SQLite. | |
3801 */ | |
3802 SQLITE_API int sqlite3_key( | |
3803 sqlite3 *db, /* Database to be rekeyed */ | |
3804 const void *pKey, int nKey /* The key */ | |
3805 ); | |
3806 | |
3807 /* | |
3808 ** Change the key on an open database. If the current database is not | |
3809 ** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the | |
3810 ** database is decrypted. | |
3811 ** | |
3812 ** The code to implement this API is not available in the public release | |
3813 ** of SQLite. | |
3814 */ | |
3815 SQLITE_API int sqlite3_rekey( | |
3816 sqlite3 *db, /* Database to be rekeyed */ | |
3817 const void *pKey, int nKey /* The new key */ | |
3818 ); | |
3819 | |
3820 /* | |
3821 ** Specify the activation key for a SEE database. Unless | |
3822 ** activated, none of the SEE routines will work. | |
3823 */ | |
3824 SQLITE_API void sqlite3_activate_see( | |
3825 const char *zPassPhrase /* Activation phrase */ | |
3826 ); | |
3827 #endif | |
3828 | |
3829 #ifdef SQLITE_ENABLE_CEROD | |
3830 /* | |
3831 ** Specify the activation key for a CEROD database. Unless | |
3832 ** activated, none of the CEROD routines will work. | |
3833 */ | |
3834 SQLITE_API void sqlite3_activate_cerod( | |
3835 const char *zPassPhrase /* Activation phrase */ | |
3836 ); | |
3837 #endif | |
3838 | |
3839 /* | |
3840 ** CAPI3REF: Suspend Execution For A Short Time | |
3841 ** | |
3842 ** ^The sqlite3_sleep() function causes the current thread to suspend execution | |
3843 ** for at least a number of milliseconds specified in its parameter. | |
3844 ** | |
3845 ** ^If the operating system does not support sleep requests with | |
3846 ** millisecond time resolution, then the time will be rounded up to | |
3847 ** the nearest second. ^The number of milliseconds of sleep actually | |
3848 ** requested from the operating system is returned. | |
3849 ** | |
3850 ** ^SQLite implements this interface by calling the xSleep() | |
3851 ** method of the default [sqlite3_vfs] object. | |
3852 */ | |
3853 SQLITE_API int sqlite3_sleep(int); | |
3854 | |
3855 /* | |
3856 ** CAPI3REF: Name Of The Folder Holding Temporary Files | |
3857 ** | |
3858 ** ^(If this global variable is made to point to a string which is | |
3859 ** the name of a folder (a.k.a. directory), then all temporary files | |
3860 ** created by SQLite when using a built-in [sqlite3_vfs | VFS] | |
3861 ** will be placed in that directory.)^ ^If this variable | |
3862 ** is a NULL pointer, then SQLite performs a search for an appropriate | |
3863 ** temporary file directory. | |
3864 ** | |
3865 ** It is not safe to read or modify this variable in more than one | |
3866 ** thread at a time. It is not safe to read or modify this variable | |
3867 ** if a [database connection] is being used at the same time in a separate | |
3868 ** thread. | |
3869 ** It is intended that this variable be set once | |
3870 ** as part of process initialization and before any SQLite interface | |
3871 ** routines have been called and that this variable remain unchanged | |
3872 ** thereafter. | |
3873 ** | |
3874 ** ^The [temp_store_directory pragma] may modify this variable and cause | |
3875 ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, | |
3876 ** the [temp_store_directory pragma] always assumes that any string | |
3877 ** that this variable points to is held in memory obtained from | |
3878 ** [sqlite3_malloc] and the pragma may attempt to free that memory | |
3879 ** using [sqlite3_free]. | |
3880 ** Hence, if this variable is modified directly, either it should be | |
3881 ** made NULL or made to point to memory obtained from [sqlite3_malloc] | |
3882 ** or else the use of the [temp_store_directory pragma] should be avoided. | |
3883 */ | |
3884 SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory; | |
3885 | |
3886 /* | |
3887 ** CAPI3REF: Test For Auto-Commit Mode | |
3888 ** KEYWORDS: {autocommit mode} | |
3889 ** | |
3890 ** ^The sqlite3_get_autocommit() interface returns non-zero or | |
3891 ** zero if the given database connection is or is not in autocommit mode, | |
3892 ** respectively. ^Autocommit mode is on by default. | |
3893 ** ^Autocommit mode is disabled by a [BEGIN] statement. | |
3894 ** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. | |
3895 ** | |
3896 ** If certain kinds of errors occur on a statement within a multi-statement | |
3897 ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], | |
3898 ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the | |
3899 ** transaction might be rolled back automatically. The only way to | |
3900 ** find out whether SQLite automatically rolled back the transaction after | |
3901 ** an error is to use this function. | |
3902 ** | |
3903 ** If another thread changes the autocommit status of the database | |
3904 ** connection while this routine is running, then the return value | |
3905 ** is undefined. | |
3906 */ | |
3907 SQLITE_API int sqlite3_get_autocommit(sqlite3*); | |
3908 | |
3909 /* | |
3910 ** CAPI3REF: Find The Database Handle Of A Prepared Statement | |
3911 ** | |
3912 ** ^The sqlite3_db_handle interface returns the [database connection] handle | |
3913 ** to which a [prepared statement] belongs. ^The [database connection] | |
3914 ** returned by sqlite3_db_handle is the same [database connection] | |
3915 ** that was the first argument | |
3916 ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to | |
3917 ** create the statement in the first place. | |
3918 */ | |
3919 SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*); | |
3920 | |
3921 /* | |
3922 ** CAPI3REF: Find the next prepared statement | |
3923 ** | |
3924 ** ^This interface returns a pointer to the next [prepared statement] after | |
3925 ** pStmt associated with the [database connection] pDb. ^If pStmt is NULL | |
3926 ** then this interface returns a pointer to the first prepared statement | |
3927 ** associated with the database connection pDb. ^If no prepared statement | |
3928 ** satisfies the conditions of this routine, it returns NULL. | |
3929 ** | |
3930 ** The [database connection] pointer D in a call to | |
3931 ** [sqlite3_next_stmt(D,S)] must refer to an open database | |
3932 ** connection and in particular must not be a NULL pointer. | |
3933 */ | |
3934 SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); | |
3935 | |
3936 /* | |
3937 ** CAPI3REF: Commit And Rollback Notification Callbacks | |
3938 ** | |
3939 ** ^The sqlite3_commit_hook() interface registers a callback | |
3940 ** function to be invoked whenever a transaction is [COMMIT | committed]. | |
3941 ** ^Any callback set by a previous call to sqlite3_commit_hook() | |
3942 ** for the same database connection is overridden. | |
3943 ** ^The sqlite3_rollback_hook() interface registers a callback | |
3944 ** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. | |
3945 ** ^Any callback set by a previous call to sqlite3_rollback_hook() | |
3946 ** for the same database connection is overridden. | |
3947 ** ^The pArg argument is passed through to the callback. | |
3948 ** ^If the callback on a commit hook function returns non-zero, | |
3949 ** then the commit is converted into a rollback. | |
3950 ** | |
3951 ** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions | |
3952 ** return the P argument from the previous call of the same function | |
3953 ** on the same [database connection] D, or NULL for | |
3954 ** the first call for each function on D. | |
3955 ** | |
3956 ** The callback implementation must not do anything that will modify | |
3957 ** the database connection that invoked the callback. Any actions | |
3958 ** to modify the database connection must be deferred until after the | |
3959 ** completion of the [sqlite3_step()] call that triggered the commit | |
3960 ** or rollback hook in the first place. | |
3961 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their | |
3962 ** database connections for the meaning of "modify" in this paragraph. | |
3963 ** | |
3964 ** ^Registering a NULL function disables the callback. | |
3965 ** | |
3966 ** ^When the commit hook callback routine returns zero, the [COMMIT] | |
3967 ** operation is allowed to continue normally. ^If the commit hook | |
3968 ** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. | |
3969 ** ^The rollback hook is invoked on a rollback that results from a commit | |
3970 ** hook returning non-zero, just as it would be with any other rollback. | |
3971 ** | |
3972 ** ^For the purposes of this API, a transaction is said to have been | |
3973 ** rolled back if an explicit "ROLLBACK" statement is executed, or | |
3974 ** an error or constraint causes an implicit rollback to occur. | |
3975 ** ^The rollback callback is not invoked if a transaction is | |
3976 ** automatically rolled back because the database connection is closed. | |
3977 ** | |
3978 ** See also the [sqlite3_update_hook()] interface. | |
3979 */ | |
3980 SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); | |
3981 SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); | |
3982 | |
3983 /* | |
3984 ** CAPI3REF: Data Change Notification Callbacks | |
3985 ** | |
3986 ** ^The sqlite3_update_hook() interface registers a callback function | |
3987 ** with the [database connection] identified by the first argument | |
3988 ** to be invoked whenever a row is updated, inserted or deleted. | |
3989 ** ^Any callback set by a previous call to this function | |
3990 ** for the same database connection is overridden. | |
3991 ** | |
3992 ** ^The second argument is a pointer to the function to invoke when a | |
3993 ** row is updated, inserted or deleted. | |
3994 ** ^The first argument to the callback is a copy of the third argument | |
3995 ** to sqlite3_update_hook(). | |
3996 ** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], | |
3997 ** or [SQLITE_UPDATE], depending on the operation that caused the callback | |
3998 ** to be invoked. | |
3999 ** ^The third and fourth arguments to the callback contain pointers to the | |
4000 ** database and table name containing the affected row. | |
4001 ** ^The final callback parameter is the [rowid] of the row. | |
4002 ** ^In the case of an update, this is the [rowid] after the update takes place. | |
4003 ** | |
4004 ** ^(The update hook is not invoked when internal system tables are | |
4005 ** modified (i.e. sqlite_master and sqlite_sequence).)^ | |
4006 ** | |
4007 ** ^In the current implementation, the update hook | |
4008 ** is not invoked when duplication rows are deleted because of an | |
4009 ** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook | |
4010 ** invoked when rows are deleted using the [truncate optimization]. | |
4011 ** The exceptions defined in this paragraph might change in a future | |
4012 ** release of SQLite. | |
4013 ** | |
4014 ** The update hook implementation must not do anything that will modify | |
4015 ** the database connection that invoked the update hook. Any actions | |
4016 ** to modify the database connection must be deferred until after the | |
4017 ** completion of the [sqlite3_step()] call that triggered the update hook. | |
4018 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their | |
4019 ** database connections for the meaning of "modify" in this paragraph. | |
4020 ** | |
4021 ** ^The sqlite3_update_hook(D,C,P) function | |
4022 ** returns the P argument from the previous call | |
4023 ** on the same [database connection] D, or NULL for | |
4024 ** the first call on D. | |
4025 ** | |
4026 ** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()] | |
4027 ** interfaces. | |
4028 */ | |
4029 SQLITE_API void *sqlite3_update_hook( | |
4030 sqlite3*, | |
4031 void(*)(void *,int ,char const *,char const *,sqlite3_int64), | |
4032 void* | |
4033 ); | |
4034 | |
4035 /* | |
4036 ** CAPI3REF: Enable Or Disable Shared Pager Cache | |
4037 ** KEYWORDS: {shared cache} | |
4038 ** | |
4039 ** ^(This routine enables or disables the sharing of the database cache | |
4040 ** and schema data structures between [database connection | connections] | |
4041 ** to the same database. Sharing is enabled if the argument is true | |
4042 ** and disabled if the argument is false.)^ | |
4043 ** | |
4044 ** ^Cache sharing is enabled and disabled for an entire process. | |
4045 ** This is a change as of SQLite version 3.5.0. In prior versions of SQLite, | |
4046 ** sharing was enabled or disabled for each thread separately. | |
4047 ** | |
4048 ** ^(The cache sharing mode set by this interface effects all subsequent | |
4049 ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. | |
4050 ** Existing database connections continue use the sharing mode | |
4051 ** that was in effect at the time they were opened.)^ | |
4052 ** | |
4053 ** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled | |
4054 ** successfully. An [error code] is returned otherwise.)^ | |
4055 ** | |
4056 ** ^Shared cache is disabled by default. But this might change in | |
4057 ** future releases of SQLite. Applications that care about shared | |
4058 ** cache setting should set it explicitly. | |
4059 ** | |
4060 ** See Also: [SQLite Shared-Cache Mode] | |
4061 */ | |
4062 SQLITE_API int sqlite3_enable_shared_cache(int); | |
4063 | |
4064 /* | |
4065 ** CAPI3REF: Attempt To Free Heap Memory | |
4066 ** | |
4067 ** ^The sqlite3_release_memory() interface attempts to free N bytes | |
4068 ** of heap memory by deallocating non-essential memory allocations | |
4069 ** held by the database library. Memory used to cache database | |
4070 ** pages to improve performance is an example of non-essential memory. | |
4071 ** ^sqlite3_release_memory() returns the number of bytes actually freed, | |
4072 ** which might be more or less than the amount requested. | |
4073 */ | |
4074 SQLITE_API int sqlite3_release_memory(int); | |
4075 | |
4076 /* | |
4077 ** CAPI3REF: Impose A Limit On Heap Size | |
4078 ** | |
4079 ** ^The sqlite3_soft_heap_limit() interface places a "soft" limit | |
4080 ** on the amount of heap memory that may be allocated by SQLite. | |
4081 ** ^If an internal allocation is requested that would exceed the | |
4082 ** soft heap limit, [sqlite3_release_memory()] is invoked one or | |
4083 ** more times to free up some space before the allocation is performed. | |
4084 ** | |
4085 ** ^The limit is called "soft" because if [sqlite3_release_memory()] | |
4086 ** cannot free sufficient memory to prevent the limit from being exceeded, | |
4087 ** the memory is allocated anyway and the current operation proceeds. | |
4088 ** | |
4089 ** ^A negative or zero value for N means that there is no soft heap limit and | |
4090 ** [sqlite3_release_memory()] will only be called when memory is exhausted. | |
4091 ** ^The default value for the soft heap limit is zero. | |
4092 ** | |
4093 ** ^(SQLite makes a best effort to honor the soft heap limit. | |
4094 ** But if the soft heap limit cannot be honored, execution will | |
4095 ** continue without error or notification.)^ This is why the limit is | |
4096 ** called a "soft" limit. It is advisory only. | |
4097 ** | |
4098 ** Prior to SQLite version 3.5.0, this routine only constrained the memory | |
4099 ** allocated by a single thread - the same thread in which this routine | |
4100 ** runs. Beginning with SQLite version 3.5.0, the soft heap limit is | |
4101 ** applied to all threads. The value specified for the soft heap limit | |
4102 ** is an upper bound on the total memory allocation for all threads. In | |
4103 ** version 3.5.0 there is no mechanism for limiting the heap usage for | |
4104 ** individual threads. | |
4105 */ | |
4106 SQLITE_API void sqlite3_soft_heap_limit(int); | |
4107 | |
4108 /* | |
4109 ** CAPI3REF: Extract Metadata About A Column Of A Table | |
4110 ** | |
4111 ** ^This routine returns metadata about a specific column of a specific | |
4112 ** database table accessible using the [database connection] handle | |
4113 ** passed as the first function argument. | |
4114 ** | |
4115 ** ^The column is identified by the second, third and fourth parameters to | |
4116 ** this function. ^The second parameter is either the name of the database | |
4117 ** (i.e. "main", "temp", or an attached database) containing the specified | |
4118 ** table or NULL. ^If it is NULL, then all attached databases are searched | |
4119 ** for the table using the same algorithm used by the database engine to | |
4120 ** resolve unqualified table references. | |
4121 ** | |
4122 ** ^The third and fourth parameters to this function are the table and column | |
4123 ** name of the desired column, respectively. Neither of these parameters | |
4124 ** may be NULL. | |
4125 ** | |
4126 ** ^Metadata is returned by writing to the memory locations passed as the 5th | |
4127 ** and subsequent parameters to this function. ^Any of these arguments may be | |
4128 ** NULL, in which case the corresponding element of metadata is omitted. | |
4129 ** | |
4130 ** ^(<blockquote> | |
4131 ** <table border="1"> | |
4132 ** <tr><th> Parameter <th> Output<br>Type <th> Description | |
4133 ** | |
4134 ** <tr><td> 5th <td> const char* <td> Data type | |
4135 ** <tr><td> 6th <td> const char* <td> Name of default collation sequence | |
4136 ** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint | |
4137 ** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY | |
4138 ** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] | |
4139 ** </table> | |
4140 ** </blockquote>)^ | |
4141 ** | |
4142 ** ^The memory pointed to by the character pointers returned for the | |
4143 ** declaration type and collation sequence is valid only until the next | |
4144 ** call to any SQLite API function. | |
4145 ** | |
4146 ** ^If the specified table is actually a view, an [error code] is returned. | |
4147 ** | |
4148 ** ^If the specified column is "rowid", "oid" or "_rowid_" and an | |
4149 ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output | |
4150 ** parameters are set for the explicitly declared column. ^(If there is no | |
4151 ** explicitly declared [INTEGER PRIMARY KEY] column, then the output | |
4152 ** parameters are set as follows: | |
4153 ** | |
4154 ** <pre> | |
4155 ** data type: "INTEGER" | |
4156 ** collation sequence: "BINARY" | |
4157 ** not null: 0 | |
4158 ** primary key: 1 | |
4159 ** auto increment: 0 | |
4160 ** </pre>)^ | |
4161 ** | |
4162 ** ^(This function may load one or more schemas from database files. If an | |
4163 ** error occurs during this process, or if the requested table or column | |
4164 ** cannot be found, an [error code] is returned and an error message left | |
4165 ** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^ | |
4166 ** | |
4167 ** ^This API is only available if the library was compiled with the | |
4168 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined. | |
4169 */ | |
4170 SQLITE_API int sqlite3_table_column_metadata( | |
4171 sqlite3 *db, /* Connection handle */ | |
4172 const char *zDbName, /* Database name or NULL */ | |
4173 const char *zTableName, /* Table name */ | |
4174 const char *zColumnName, /* Column name */ | |
4175 char const **pzDataType, /* OUTPUT: Declared data type */ | |
4176 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ | |
4177 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ | |
4178 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ | |
4179 int *pAutoinc /* OUTPUT: True if column is auto-increment */ | |
4180 ); | |
4181 | |
4182 /* | |
4183 ** CAPI3REF: Load An Extension | |
4184 ** | |
4185 ** ^This interface loads an SQLite extension library from the named file. | |
4186 ** | |
4187 ** ^The sqlite3_load_extension() interface attempts to load an | |
4188 ** SQLite extension library contained in the file zFile. | |
4189 ** | |
4190 ** ^The entry point is zProc. | |
4191 ** ^zProc may be 0, in which case the name of the entry point | |
4192 ** defaults to "sqlite3_extension_init". | |
4193 ** ^The sqlite3_load_extension() interface returns | |
4194 ** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. | |
4195 ** ^If an error occurs and pzErrMsg is not 0, then the | |
4196 ** [sqlite3_load_extension()] interface shall attempt to | |
4197 ** fill *pzErrMsg with error message text stored in memory | |
4198 ** obtained from [sqlite3_malloc()]. The calling function | |
4199 ** should free this memory by calling [sqlite3_free()]. | |
4200 ** | |
4201 ** ^Extension loading must be enabled using | |
4202 ** [sqlite3_enable_load_extension()] prior to calling this API, | |
4203 ** otherwise an error will be returned. | |
4204 ** | |
4205 ** See also the [load_extension() SQL function]. | |
4206 */ | |
4207 SQLITE_API int sqlite3_load_extension( | |
4208 sqlite3 *db, /* Load the extension into this database connection */ | |
4209 const char *zFile, /* Name of the shared library containing extension */ | |
4210 const char *zProc, /* Entry point. Derived from zFile if 0 */ | |
4211 char **pzErrMsg /* Put error message here if not 0 */ | |
4212 ); | |
4213 | |
4214 /* | |
4215 ** CAPI3REF: Enable Or Disable Extension Loading | |
4216 ** | |
4217 ** ^So as not to open security holes in older applications that are | |
4218 ** unprepared to deal with extension loading, and as a means of disabling | |
4219 ** extension loading while evaluating user-entered SQL, the following API | |
4220 ** is provided to turn the [sqlite3_load_extension()] mechanism on and off. | |
4221 ** | |
4222 ** ^Extension loading is off by default. See ticket #1863. | |
4223 ** ^Call the sqlite3_enable_load_extension() routine with onoff==1 | |
4224 ** to turn extension loading on and call it with onoff==0 to turn | |
4225 ** it back off again. | |
4226 */ | |
4227 SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff); | |
4228 | |
4229 /* | |
4230 ** CAPI3REF: Automatically Load An Extensions | |
4231 ** | |
4232 ** ^This API can be invoked at program startup in order to register | |
4233 ** one or more statically linked extensions that will be available | |
4234 ** to all new [database connections]. | |
4235 ** | |
4236 ** ^(This routine stores a pointer to the extension entry point | |
4237 ** in an array that is obtained from [sqlite3_malloc()]. That memory | |
4238 ** is deallocated by [sqlite3_reset_auto_extension()].)^ | |
4239 ** | |
4240 ** ^This function registers an extension entry point that is | |
4241 ** automatically invoked whenever a new [database connection] | |
4242 ** is opened using [sqlite3_open()], [sqlite3_open16()], | |
4243 ** or [sqlite3_open_v2()]. | |
4244 ** ^Duplicate extensions are detected so calling this routine | |
4245 ** multiple times with the same extension is harmless. | |
4246 ** ^Automatic extensions apply across all threads. | |
4247 */ | |
4248 SQLITE_API int sqlite3_auto_extension(void (*xEntryPoint)(void)); | |
4249 | |
4250 /* | |
4251 ** CAPI3REF: Reset Automatic Extension Loading | |
4252 ** | |
4253 ** ^(This function disables all previously registered automatic | |
4254 ** extensions. It undoes the effect of all prior | |
4255 ** [sqlite3_auto_extension()] calls.)^ | |
4256 ** | |
4257 ** ^This function disables automatic extensions in all threads. | |
4258 */ | |
4259 SQLITE_API void sqlite3_reset_auto_extension(void); | |
4260 | |
4261 /* | |
4262 ** The interface to the virtual-table mechanism is currently considered | |
4263 ** to be experimental. The interface might change in incompatible ways. | |
4264 ** If this is a problem for you, do not use the interface at this time. | |
4265 ** | |
4266 ** When the virtual-table mechanism stabilizes, we will declare the | |
4267 ** interface fixed, support it indefinitely, and remove this comment. | |
4268 */ | |
4269 | |
4270 /* | |
4271 ** Structures used by the virtual table interface | |
4272 */ | |
4273 typedef struct sqlite3_vtab sqlite3_vtab; | |
4274 typedef struct sqlite3_index_info sqlite3_index_info; | |
4275 typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; | |
4276 typedef struct sqlite3_module sqlite3_module; | |
4277 | |
4278 /* | |
4279 ** CAPI3REF: Virtual Table Object | |
4280 ** KEYWORDS: sqlite3_module {virtual table module} | |
4281 ** | |
4282 ** This structure, sometimes called a a "virtual table module", | |
4283 ** defines the implementation of a [virtual tables]. | |
4284 ** This structure consists mostly of methods for the module. | |
4285 ** | |
4286 ** ^A virtual table module is created by filling in a persistent | |
4287 ** instance of this structure and passing a pointer to that instance | |
4288 ** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. | |
4289 ** ^The registration remains valid until it is replaced by a different | |
4290 ** module or until the [database connection] closes. The content | |
4291 ** of this structure must not change while it is registered with | |
4292 ** any database connection. | |
4293 */ | |
4294 struct sqlite3_module { | |
4295 int iVersion; | |
4296 int (*xCreate)(sqlite3*, void *pAux, | |
4297 int argc, const char *const*argv, | |
4298 sqlite3_vtab **ppVTab, char**); | |
4299 int (*xConnect)(sqlite3*, void *pAux, | |
4300 int argc, const char *const*argv, | |
4301 sqlite3_vtab **ppVTab, char**); | |
4302 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); | |
4303 int (*xDisconnect)(sqlite3_vtab *pVTab); | |
4304 int (*xDestroy)(sqlite3_vtab *pVTab); | |
4305 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); | |
4306 int (*xClose)(sqlite3_vtab_cursor*); | |
4307 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, | |
4308 int argc, sqlite3_value **argv); | |
4309 int (*xNext)(sqlite3_vtab_cursor*); | |
4310 int (*xEof)(sqlite3_vtab_cursor*); | |
4311 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); | |
4312 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); | |
4313 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); | |
4314 int (*xBegin)(sqlite3_vtab *pVTab); | |
4315 int (*xSync)(sqlite3_vtab *pVTab); | |
4316 int (*xCommit)(sqlite3_vtab *pVTab); | |
4317 int (*xRollback)(sqlite3_vtab *pVTab); | |
4318 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, | |
4319 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), | |
4320 void **ppArg); | |
4321 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); | |
4322 }; | |
4323 | |
4324 /* | |
4325 ** CAPI3REF: Virtual Table Indexing Information | |
4326 ** KEYWORDS: sqlite3_index_info | |
4327 ** | |
4328 ** The sqlite3_index_info structure and its substructures is used to | |
4329 ** pass information into and receive the reply from the [xBestIndex] | |
4330 ** method of a [virtual table module]. The fields under **Inputs** are the | |
4331 ** inputs to xBestIndex and are read-only. xBestIndex inserts its | |
4332 ** results into the **Outputs** fields. | |
4333 ** | |
4334 ** ^(The aConstraint[] array records WHERE clause constraints of the form: | |
4335 ** | |
4336 ** <pre>column OP expr</pre> | |
4337 ** | |
4338 ** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is | |
4339 ** stored in aConstraint[].op.)^ ^(The index of the column is stored in | |
4340 ** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the | |
4341 ** expr on the right-hand side can be evaluated (and thus the constraint | |
4342 ** is usable) and false if it cannot.)^ | |
4343 ** | |
4344 ** ^The optimizer automatically inverts terms of the form "expr OP column" | |
4345 ** and makes other simplifications to the WHERE clause in an attempt to | |
4346 ** get as many WHERE clause terms into the form shown above as possible. | |
4347 ** ^The aConstraint[] array only reports WHERE clause terms that are | |
4348 ** relevant to the particular virtual table being queried. | |
4349 ** | |
4350 ** ^Information about the ORDER BY clause is stored in aOrderBy[]. | |
4351 ** ^Each term of aOrderBy records a column of the ORDER BY clause. | |
4352 ** | |
4353 ** The [xBestIndex] method must fill aConstraintUsage[] with information | |
4354 ** about what parameters to pass to xFilter. ^If argvIndex>0 then | |
4355 ** the right-hand side of the corresponding aConstraint[] is evaluated | |
4356 ** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit | |
4357 ** is true, then the constraint is assumed to be fully handled by the | |
4358 ** virtual table and is not checked again by SQLite.)^ | |
4359 ** | |
4360 ** ^The idxNum and idxPtr values are recorded and passed into the | |
4361 ** [xFilter] method. | |
4362 ** ^[sqlite3_free()] is used to free idxPtr if and only if | |
4363 ** needToFreeIdxPtr is true. | |
4364 ** | |
4365 ** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in | |
4366 ** the correct order to satisfy the ORDER BY clause so that no separate | |
4367 ** sorting step is required. | |
4368 ** | |
4369 ** ^The estimatedCost value is an estimate of the cost of doing the | |
4370 ** particular lookup. A full scan of a table with N entries should have | |
4371 ** a cost of N. A binary search of a table of N entries should have a | |
4372 ** cost of approximately log(N). | |
4373 */ | |
4374 struct sqlite3_index_info { | |
4375 /* Inputs */ | |
4376 int nConstraint; /* Number of entries in aConstraint */ | |
4377 struct sqlite3_index_constraint { | |
4378 int iColumn; /* Column on left-hand side of constraint */ | |
4379 unsigned char op; /* Constraint operator */ | |
4380 unsigned char usable; /* True if this constraint is usable */ | |
4381 int iTermOffset; /* Used internally - xBestIndex should ignore */ | |
4382 } *aConstraint; /* Table of WHERE clause constraints */ | |
4383 int nOrderBy; /* Number of terms in the ORDER BY clause */ | |
4384 struct sqlite3_index_orderby { | |
4385 int iColumn; /* Column number */ | |
4386 unsigned char desc; /* True for DESC. False for ASC. */ | |
4387 } *aOrderBy; /* The ORDER BY clause */ | |
4388 /* Outputs */ | |
4389 struct sqlite3_index_constraint_usage { | |
4390 int argvIndex; /* if >0, constraint is part of argv to xFilter */ | |
4391 unsigned char omit; /* Do not code a test for this constraint */ | |
4392 } *aConstraintUsage; | |
4393 int idxNum; /* Number used to identify the index */ | |
4394 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ | |
4395 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ | |
4396 int orderByConsumed; /* True if output is already ordered */ | |
4397 double estimatedCost; /* Estimated cost of using this index */ | |
4398 }; | |
4399 #define SQLITE_INDEX_CONSTRAINT_EQ 2 | |
4400 #define SQLITE_INDEX_CONSTRAINT_GT 4 | |
4401 #define SQLITE_INDEX_CONSTRAINT_LE 8 | |
4402 #define SQLITE_INDEX_CONSTRAINT_LT 16 | |
4403 #define SQLITE_INDEX_CONSTRAINT_GE 32 | |
4404 #define SQLITE_INDEX_CONSTRAINT_MATCH 64 | |
4405 | |
4406 /* | |
4407 ** CAPI3REF: Register A Virtual Table Implementation | |
4408 ** | |
4409 ** ^These routines are used to register a new [virtual table module] name. | |
4410 ** ^Module names must be registered before | |
4411 ** creating a new [virtual table] using the module and before using a | |
4412 ** preexisting [virtual table] for the module. | |
4413 ** | |
4414 ** ^The module name is registered on the [database connection] specified | |
4415 ** by the first parameter. ^The name of the module is given by the | |
4416 ** second parameter. ^The third parameter is a pointer to | |
4417 ** the implementation of the [virtual table module]. ^The fourth | |
4418 ** parameter is an arbitrary client data pointer that is passed through | |
4419 ** into the [xCreate] and [xConnect] methods of the virtual table module | |
4420 ** when a new virtual table is be being created or reinitialized. | |
4421 ** | |
4422 ** ^The sqlite3_create_module_v2() interface has a fifth parameter which | |
4423 ** is a pointer to a destructor for the pClientData. ^SQLite will | |
4424 ** invoke the destructor function (if it is not NULL) when SQLite | |
4425 ** no longer needs the pClientData pointer. ^The sqlite3_create_module() | |
4426 ** interface is equivalent to sqlite3_create_module_v2() with a NULL | |
4427 ** destructor. | |
4428 */ | |
4429 SQLITE_API int sqlite3_create_module( | |
4430 sqlite3 *db, /* SQLite connection to register module with */ | |
4431 const char *zName, /* Name of the module */ | |
4432 const sqlite3_module *p, /* Methods for the module */ | |
4433 void *pClientData /* Client data for xCreate/xConnect */ | |
4434 ); | |
4435 SQLITE_API int sqlite3_create_module_v2( | |
4436 sqlite3 *db, /* SQLite connection to register module with */ | |
4437 const char *zName, /* Name of the module */ | |
4438 const sqlite3_module *p, /* Methods for the module */ | |
4439 void *pClientData, /* Client data for xCreate/xConnect */ | |
4440 void(*xDestroy)(void*) /* Module destructor function */ | |
4441 ); | |
4442 | |
4443 /* | |
4444 ** CAPI3REF: Virtual Table Instance Object | |
4445 ** KEYWORDS: sqlite3_vtab | |
4446 ** | |
4447 ** Every [virtual table module] implementation uses a subclass | |
4448 ** of this object to describe a particular instance | |
4449 ** of the [virtual table]. Each subclass will | |
4450 ** be tailored to the specific needs of the module implementation. | |
4451 ** The purpose of this superclass is to define certain fields that are | |
4452 ** common to all module implementations. | |
4453 ** | |
4454 ** ^Virtual tables methods can set an error message by assigning a | |
4455 ** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should | |
4456 ** take care that any prior string is freed by a call to [sqlite3_free()] | |
4457 ** prior to assigning a new string to zErrMsg. ^After the error message | |
4458 ** is delivered up to the client application, the string will be automatically | |
4459 ** freed by sqlite3_free() and the zErrMsg field will be zeroed. | |
4460 */ | |
4461 struct sqlite3_vtab { | |
4462 const sqlite3_module *pModule; /* The module for this virtual table */ | |
4463 int nRef; /* NO LONGER USED */ | |
4464 char *zErrMsg; /* Error message from sqlite3_mprintf() */ | |
4465 /* Virtual table implementations will typically add additional fields */ | |
4466 }; | |
4467 | |
4468 /* | |
4469 ** CAPI3REF: Virtual Table Cursor Object | |
4470 ** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} | |
4471 ** | |
4472 ** Every [virtual table module] implementation uses a subclass of the | |
4473 ** following structure to describe cursors that point into the | |
4474 ** [virtual table] and are used | |
4475 ** to loop through the virtual table. Cursors are created using the | |
4476 ** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed | |
4477 ** by the [sqlite3_module.xClose | xClose] method. Cursors are used | |
4478 ** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods | |
4479 ** of the module. Each module implementation will define | |
4480 ** the content of a cursor structure to suit its own needs. | |
4481 ** | |
4482 ** This superclass exists in order to define fields of the cursor that | |
4483 ** are common to all implementations. | |
4484 */ | |
4485 struct sqlite3_vtab_cursor { | |
4486 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ | |
4487 /* Virtual table implementations will typically add additional fields */ | |
4488 }; | |
4489 | |
4490 /* | |
4491 ** CAPI3REF: Declare The Schema Of A Virtual Table | |
4492 ** | |
4493 ** ^The [xCreate] and [xConnect] methods of a | |
4494 ** [virtual table module] call this interface | |
4495 ** to declare the format (the names and datatypes of the columns) of | |
4496 ** the virtual tables they implement. | |
4497 */ | |
4498 SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL); | |
4499 | |
4500 /* | |
4501 ** CAPI3REF: Overload A Function For A Virtual Table | |
4502 ** | |
4503 ** ^(Virtual tables can provide alternative implementations of functions | |
4504 ** using the [xFindFunction] method of the [virtual table module]. | |
4505 ** But global versions of those functions | |
4506 ** must exist in order to be overloaded.)^ | |
4507 ** | |
4508 ** ^(This API makes sure a global version of a function with a particular | |
4509 ** name and number of parameters exists. If no such function exists | |
4510 ** before this API is called, a new function is created.)^ ^The implementation | |
4511 ** of the new function always causes an exception to be thrown. So | |
4512 ** the new function is not good for anything by itself. Its only | |
4513 ** purpose is to be a placeholder function that can be overloaded | |
4514 ** by a [virtual table]. | |
4515 */ | |
4516 SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); | |
4517 | |
4518 /* | |
4519 ** The interface to the virtual-table mechanism defined above (back up | |
4520 ** to a comment remarkably similar to this one) is currently considered | |
4521 ** to be experimental. The interface might change in incompatible ways. | |
4522 ** If this is a problem for you, do not use the interface at this time. | |
4523 ** | |
4524 ** When the virtual-table mechanism stabilizes, we will declare the | |
4525 ** interface fixed, support it indefinitely, and remove this comment. | |
4526 */ | |
4527 | |
4528 /* | |
4529 ** CAPI3REF: A Handle To An Open BLOB | |
4530 ** KEYWORDS: {BLOB handle} {BLOB handles} | |
4531 ** | |
4532 ** An instance of this object represents an open BLOB on which | |
4533 ** [sqlite3_blob_open | incremental BLOB I/O] can be performed. | |
4534 ** ^Objects of this type are created by [sqlite3_blob_open()] | |
4535 ** and destroyed by [sqlite3_blob_close()]. | |
4536 ** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces | |
4537 ** can be used to read or write small subsections of the BLOB. | |
4538 ** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. | |
4539 */ | |
4540 typedef struct sqlite3_blob sqlite3_blob; | |
4541 | |
4542 /* | |
4543 ** CAPI3REF: Open A BLOB For Incremental I/O | |
4544 ** | |
4545 ** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located | |
4546 ** in row iRow, column zColumn, table zTable in database zDb; | |
4547 ** in other words, the same BLOB that would be selected by: | |
4548 ** | |
4549 ** <pre> | |
4550 ** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; | |
4551 ** </pre>)^ | |
4552 ** | |
4553 ** ^If the flags parameter is non-zero, then the BLOB is opened for read | |
4554 ** and write access. ^If it is zero, the BLOB is opened for read access. | |
4555 ** ^It is not possible to open a column that is part of an index or primary | |
4556 ** key for writing. ^If [foreign key constraints] are enabled, it is | |
4557 ** not possible to open a column that is part of a [child key] for writing. | |
4558 ** | |
4559 ** ^Note that the database name is not the filename that contains | |
4560 ** the database but rather the symbolic name of the database that | |
4561 ** appears after the AS keyword when the database is connected using [ATTACH]. | |
4562 ** ^For the main database file, the database name is "main". | |
4563 ** ^For TEMP tables, the database name is "temp". | |
4564 ** | |
4565 ** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written | |
4566 ** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set | |
4567 ** to be a null pointer.)^ | |
4568 ** ^This function sets the [database connection] error code and message | |
4569 ** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related | |
4570 ** functions. ^Note that the *ppBlob variable is always initialized in a | |
4571 ** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob | |
4572 ** regardless of the success or failure of this routine. | |
4573 ** | |
4574 ** ^(If the row that a BLOB handle points to is modified by an | |
4575 ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects | |
4576 ** then the BLOB handle is marked as "expired". | |
4577 ** This is true if any column of the row is changed, even a column | |
4578 ** other than the one the BLOB handle is open on.)^ | |
4579 ** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for | |
4580 ** a expired BLOB handle fail with an return code of [SQLITE_ABORT]. | |
4581 ** ^(Changes written into a BLOB prior to the BLOB expiring are not | |
4582 ** rolled back by the expiration of the BLOB. Such changes will eventually | |
4583 ** commit if the transaction continues to completion.)^ | |
4584 ** | |
4585 ** ^Use the [sqlite3_blob_bytes()] interface to determine the size of | |
4586 ** the opened blob. ^The size of a blob may not be changed by this | |
4587 ** interface. Use the [UPDATE] SQL command to change the size of a | |
4588 ** blob. | |
4589 ** | |
4590 ** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces | |
4591 ** and the built-in [zeroblob] SQL function can be used, if desired, | |
4592 ** to create an empty, zero-filled blob in which to read or write using | |
4593 ** this interface. | |
4594 ** | |
4595 ** To avoid a resource leak, every open [BLOB handle] should eventually | |
4596 ** be released by a call to [sqlite3_blob_close()]. | |
4597 */ | |
4598 SQLITE_API int sqlite3_blob_open( | |
4599 sqlite3*, | |
4600 const char *zDb, | |
4601 const char *zTable, | |
4602 const char *zColumn, | |
4603 sqlite3_int64 iRow, | |
4604 int flags, | |
4605 sqlite3_blob **ppBlob | |
4606 ); | |
4607 | |
4608 /* | |
4609 ** CAPI3REF: Close A BLOB Handle | |
4610 ** | |
4611 ** ^Closes an open [BLOB handle]. | |
4612 ** | |
4613 ** ^Closing a BLOB shall cause the current transaction to commit | |
4614 ** if there are no other BLOBs, no pending prepared statements, and the | |
4615 ** database connection is in [autocommit mode]. | |
4616 ** ^If any writes were made to the BLOB, they might be held in cache | |
4617 ** until the close operation if they will fit. | |
4618 ** | |
4619 ** ^(Closing the BLOB often forces the changes | |
4620 ** out to disk and so if any I/O errors occur, they will likely occur | |
4621 ** at the time when the BLOB is closed. Any errors that occur during | |
4622 ** closing are reported as a non-zero return value.)^ | |
4623 ** | |
4624 ** ^(The BLOB is closed unconditionally. Even if this routine returns | |
4625 ** an error code, the BLOB is still closed.)^ | |
4626 ** | |
4627 ** ^Calling this routine with a null pointer (such as would be returned | |
4628 ** by a failed call to [sqlite3_blob_open()]) is a harmless no-op. | |
4629 */ | |
4630 SQLITE_API int sqlite3_blob_close(sqlite3_blob *); | |
4631 | |
4632 /* | |
4633 ** CAPI3REF: Return The Size Of An Open BLOB | |
4634 ** | |
4635 ** ^Returns the size in bytes of the BLOB accessible via the | |
4636 ** successfully opened [BLOB handle] in its only argument. ^The | |
4637 ** incremental blob I/O routines can only read or overwriting existing | |
4638 ** blob content; they cannot change the size of a blob. | |
4639 ** | |
4640 ** This routine only works on a [BLOB handle] which has been created | |
4641 ** by a prior successful call to [sqlite3_blob_open()] and which has not | |
4642 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in | |
4643 ** to this routine results in undefined and probably undesirable behavior. | |
4644 */ | |
4645 SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *); | |
4646 | |
4647 /* | |
4648 ** CAPI3REF: Read Data From A BLOB Incrementally | |
4649 ** | |
4650 ** ^(This function is used to read data from an open [BLOB handle] into a | |
4651 ** caller-supplied buffer. N bytes of data are copied into buffer Z | |
4652 ** from the open BLOB, starting at offset iOffset.)^ | |
4653 ** | |
4654 ** ^If offset iOffset is less than N bytes from the end of the BLOB, | |
4655 ** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is | |
4656 ** less than zero, [SQLITE_ERROR] is returned and no data is read. | |
4657 ** ^The size of the blob (and hence the maximum value of N+iOffset) | |
4658 ** can be determined using the [sqlite3_blob_bytes()] interface. | |
4659 ** | |
4660 ** ^An attempt to read from an expired [BLOB handle] fails with an | |
4661 ** error code of [SQLITE_ABORT]. | |
4662 ** | |
4663 ** ^(On success, sqlite3_blob_read() returns SQLITE_OK. | |
4664 ** Otherwise, an [error code] or an [extended error code] is returned.)^ | |
4665 ** | |
4666 ** This routine only works on a [BLOB handle] which has been created | |
4667 ** by a prior successful call to [sqlite3_blob_open()] and which has not | |
4668 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in | |
4669 ** to this routine results in undefined and probably undesirable behavior. | |
4670 ** | |
4671 ** See also: [sqlite3_blob_write()]. | |
4672 */ | |
4673 SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); | |
4674 | |
4675 /* | |
4676 ** CAPI3REF: Write Data Into A BLOB Incrementally | |
4677 ** | |
4678 ** ^This function is used to write data into an open [BLOB handle] from a | |
4679 ** caller-supplied buffer. ^N bytes of data are copied from the buffer Z | |
4680 ** into the open BLOB, starting at offset iOffset. | |
4681 ** | |
4682 ** ^If the [BLOB handle] passed as the first argument was not opened for | |
4683 ** writing (the flags parameter to [sqlite3_blob_open()] was zero), | |
4684 ** this function returns [SQLITE_READONLY]. | |
4685 ** | |
4686 ** ^This function may only modify the contents of the BLOB; it is | |
4687 ** not possible to increase the size of a BLOB using this API. | |
4688 ** ^If offset iOffset is less than N bytes from the end of the BLOB, | |
4689 ** [SQLITE_ERROR] is returned and no data is written. ^If N is | |
4690 ** less than zero [SQLITE_ERROR] is returned and no data is written. | |
4691 ** The size of the BLOB (and hence the maximum value of N+iOffset) | |
4692 ** can be determined using the [sqlite3_blob_bytes()] interface. | |
4693 ** | |
4694 ** ^An attempt to write to an expired [BLOB handle] fails with an | |
4695 ** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred | |
4696 ** before the [BLOB handle] expired are not rolled back by the | |
4697 ** expiration of the handle, though of course those changes might | |
4698 ** have been overwritten by the statement that expired the BLOB handle | |
4699 ** or by other independent statements. | |
4700 ** | |
4701 ** ^(On success, sqlite3_blob_write() returns SQLITE_OK. | |
4702 ** Otherwise, an [error code] or an [extended error code] is returned.)^ | |
4703 ** | |
4704 ** This routine only works on a [BLOB handle] which has been created | |
4705 ** by a prior successful call to [sqlite3_blob_open()] and which has not | |
4706 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in | |
4707 ** to this routine results in undefined and probably undesirable behavior. | |
4708 ** | |
4709 ** See also: [sqlite3_blob_read()]. | |
4710 */ | |
4711 SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); | |
4712 | |
4713 /* | |
4714 ** CAPI3REF: Virtual File System Objects | |
4715 ** | |
4716 ** A virtual filesystem (VFS) is an [sqlite3_vfs] object | |
4717 ** that SQLite uses to interact | |
4718 ** with the underlying operating system. Most SQLite builds come with a | |
4719 ** single default VFS that is appropriate for the host computer. | |
4720 ** New VFSes can be registered and existing VFSes can be unregistered. | |
4721 ** The following interfaces are provided. | |
4722 ** | |
4723 ** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. | |
4724 ** ^Names are case sensitive. | |
4725 ** ^Names are zero-terminated UTF-8 strings. | |
4726 ** ^If there is no match, a NULL pointer is returned. | |
4727 ** ^If zVfsName is NULL then the default VFS is returned. | |
4728 ** | |
4729 ** ^New VFSes are registered with sqlite3_vfs_register(). | |
4730 ** ^Each new VFS becomes the default VFS if the makeDflt flag is set. | |
4731 ** ^The same VFS can be registered multiple times without injury. | |
4732 ** ^To make an existing VFS into the default VFS, register it again | |
4733 ** with the makeDflt flag set. If two different VFSes with the | |
4734 ** same name are registered, the behavior is undefined. If a | |
4735 ** VFS is registered with a name that is NULL or an empty string, | |
4736 ** then the behavior is undefined. | |
4737 ** | |
4738 ** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. | |
4739 ** ^(If the default VFS is unregistered, another VFS is chosen as | |
4740 ** the default. The choice for the new VFS is arbitrary.)^ | |
4741 */ | |
4742 SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); | |
4743 SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); | |
4744 SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*); | |
4745 | |
4746 /* | |
4747 ** CAPI3REF: Mutexes | |
4748 ** | |
4749 ** The SQLite core uses these routines for thread | |
4750 ** synchronization. Though they are intended for internal | |
4751 ** use by SQLite, code that links against SQLite is | |
4752 ** permitted to use any of these routines. | |
4753 ** | |
4754 ** The SQLite source code contains multiple implementations | |
4755 ** of these mutex routines. An appropriate implementation | |
4756 ** is selected automatically at compile-time. ^(The following | |
4757 ** implementations are available in the SQLite core: | |
4758 ** | |
4759 ** <ul> | |
4760 ** <li> SQLITE_MUTEX_OS2 | |
4761 ** <li> SQLITE_MUTEX_PTHREAD | |
4762 ** <li> SQLITE_MUTEX_W32 | |
4763 ** <li> SQLITE_MUTEX_NOOP | |
4764 ** </ul>)^ | |
4765 ** | |
4766 ** ^The SQLITE_MUTEX_NOOP implementation is a set of routines | |
4767 ** that does no real locking and is appropriate for use in | |
4768 ** a single-threaded application. ^The SQLITE_MUTEX_OS2, | |
4769 ** SQLITE_MUTEX_PTHREAD, and SQLITE_MUTEX_W32 implementations | |
4770 ** are appropriate for use on OS/2, Unix, and Windows. | |
4771 ** | |
4772 ** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor | |
4773 ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex | |
4774 ** implementation is included with the library. In this case the | |
4775 ** application must supply a custom mutex implementation using the | |
4776 ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function | |
4777 ** before calling sqlite3_initialize() or any other public sqlite3_ | |
4778 ** function that calls sqlite3_initialize().)^ | |
4779 ** | |
4780 ** ^The sqlite3_mutex_alloc() routine allocates a new | |
4781 ** mutex and returns a pointer to it. ^If it returns NULL | |
4782 ** that means that a mutex could not be allocated. ^SQLite | |
4783 ** will unwind its stack and return an error. ^(The argument | |
4784 ** to sqlite3_mutex_alloc() is one of these integer constants: | |
4785 ** | |
4786 ** <ul> | |
4787 ** <li> SQLITE_MUTEX_FAST | |
4788 ** <li> SQLITE_MUTEX_RECURSIVE | |
4789 ** <li> SQLITE_MUTEX_STATIC_MASTER | |
4790 ** <li> SQLITE_MUTEX_STATIC_MEM | |
4791 ** <li> SQLITE_MUTEX_STATIC_MEM2 | |
4792 ** <li> SQLITE_MUTEX_STATIC_PRNG | |
4793 ** <li> SQLITE_MUTEX_STATIC_LRU | |
4794 ** <li> SQLITE_MUTEX_STATIC_LRU2 | |
4795 ** </ul>)^ | |
4796 ** | |
4797 ** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) | |
4798 ** cause sqlite3_mutex_alloc() to create | |
4799 ** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE | |
4800 ** is used but not necessarily so when SQLITE_MUTEX_FAST is used. | |
4801 ** The mutex implementation does not need to make a distinction | |
4802 ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does | |
4803 ** not want to. ^SQLite will only request a recursive mutex in | |
4804 ** cases where it really needs one. ^If a faster non-recursive mutex | |
4805 ** implementation is available on the host platform, the mutex subsystem | |
4806 ** might return such a mutex in response to SQLITE_MUTEX_FAST. | |
4807 ** | |
4808 ** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other | |
4809 ** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return | |
4810 ** a pointer to a static preexisting mutex. ^Six static mutexes are | |
4811 ** used by the current version of SQLite. Future versions of SQLite | |
4812 ** may add additional static mutexes. Static mutexes are for internal | |
4813 ** use by SQLite only. Applications that use SQLite mutexes should | |
4814 ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or | |
4815 ** SQLITE_MUTEX_RECURSIVE. | |
4816 ** | |
4817 ** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST | |
4818 ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() | |
4819 ** returns a different mutex on every call. ^But for the static | |
4820 ** mutex types, the same mutex is returned on every call that has | |
4821 ** the same type number. | |
4822 ** | |
4823 ** ^The sqlite3_mutex_free() routine deallocates a previously | |
4824 ** allocated dynamic mutex. ^SQLite is careful to deallocate every | |
4825 ** dynamic mutex that it allocates. The dynamic mutexes must not be in | |
4826 ** use when they are deallocated. Attempting to deallocate a static | |
4827 ** mutex results in undefined behavior. ^SQLite never deallocates | |
4828 ** a static mutex. | |
4829 ** | |
4830 ** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt | |
4831 ** to enter a mutex. ^If another thread is already within the mutex, | |
4832 ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return | |
4833 ** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] | |
4834 ** upon successful entry. ^(Mutexes created using | |
4835 ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. | |
4836 ** In such cases the, | |
4837 ** mutex must be exited an equal number of times before another thread | |
4838 ** can enter.)^ ^(If the same thread tries to enter any other | |
4839 ** kind of mutex more than once, the behavior is undefined. | |
4840 ** SQLite will never exhibit | |
4841 ** such behavior in its own use of mutexes.)^ | |
4842 ** | |
4843 ** ^(Some systems (for example, Windows 95) do not support the operation | |
4844 ** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() | |
4845 ** will always return SQLITE_BUSY. The SQLite core only ever uses | |
4846 ** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^ | |
4847 ** | |
4848 ** ^The sqlite3_mutex_leave() routine exits a mutex that was | |
4849 ** previously entered by the same thread. ^(The behavior | |
4850 ** is undefined if the mutex is not currently entered by the | |
4851 ** calling thread or is not currently allocated. SQLite will | |
4852 ** never do either.)^ | |
4853 ** | |
4854 ** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or | |
4855 ** sqlite3_mutex_leave() is a NULL pointer, then all three routines | |
4856 ** behave as no-ops. | |
4857 ** | |
4858 ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. | |
4859 */ | |
4860 SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int); | |
4861 SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*); | |
4862 SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*); | |
4863 SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*); | |
4864 SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*); | |
4865 | |
4866 /* | |
4867 ** CAPI3REF: Mutex Methods Object | |
4868 ** | |
4869 ** An instance of this structure defines the low-level routines | |
4870 ** used to allocate and use mutexes. | |
4871 ** | |
4872 ** Usually, the default mutex implementations provided by SQLite are | |
4873 ** sufficient, however the user has the option of substituting a custom | |
4874 ** implementation for specialized deployments or systems for which SQLite | |
4875 ** does not provide a suitable implementation. In this case, the user | |
4876 ** creates and populates an instance of this structure to pass | |
4877 ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. | |
4878 ** Additionally, an instance of this structure can be used as an | |
4879 ** output variable when querying the system for the current mutex | |
4880 ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. | |
4881 ** | |
4882 ** ^The xMutexInit method defined by this structure is invoked as | |
4883 ** part of system initialization by the sqlite3_initialize() function. | |
4884 ** ^The xMutexInit routine is calle by SQLite exactly once for each | |
4885 ** effective call to [sqlite3_initialize()]. | |
4886 ** | |
4887 ** ^The xMutexEnd method defined by this structure is invoked as | |
4888 ** part of system shutdown by the sqlite3_shutdown() function. The | |
4889 ** implementation of this method is expected to release all outstanding | |
4890 ** resources obtained by the mutex methods implementation, especially | |
4891 ** those obtained by the xMutexInit method. ^The xMutexEnd() | |
4892 ** interface is invoked exactly once for each call to [sqlite3_shutdown()]. | |
4893 ** | |
4894 ** ^(The remaining seven methods defined by this structure (xMutexAlloc, | |
4895 ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and | |
4896 ** xMutexNotheld) implement the following interfaces (respectively): | |
4897 ** | |
4898 ** <ul> | |
4899 ** <li> [sqlite3_mutex_alloc()] </li> | |
4900 ** <li> [sqlite3_mutex_free()] </li> | |
4901 ** <li> [sqlite3_mutex_enter()] </li> | |
4902 ** <li> [sqlite3_mutex_try()] </li> | |
4903 ** <li> [sqlite3_mutex_leave()] </li> | |
4904 ** <li> [sqlite3_mutex_held()] </li> | |
4905 ** <li> [sqlite3_mutex_notheld()] </li> | |
4906 ** </ul>)^ | |
4907 ** | |
4908 ** The only difference is that the public sqlite3_XXX functions enumerated | |
4909 ** above silently ignore any invocations that pass a NULL pointer instead | |
4910 ** of a valid mutex handle. The implementations of the methods defined | |
4911 ** by this structure are not required to handle this case, the results | |
4912 ** of passing a NULL pointer instead of a valid mutex handle are undefined | |
4913 ** (i.e. it is acceptable to provide an implementation that segfaults if | |
4914 ** it is passed a NULL pointer). | |
4915 ** | |
4916 ** The xMutexInit() method must be threadsafe. ^It must be harmless to | |
4917 ** invoke xMutexInit() mutiple times within the same process and without | |
4918 ** intervening calls to xMutexEnd(). Second and subsequent calls to | |
4919 ** xMutexInit() must be no-ops. | |
4920 ** | |
4921 ** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] | |
4922 ** and its associates). ^Similarly, xMutexAlloc() must not use SQLite memory | |
4923 ** allocation for a static mutex. ^However xMutexAlloc() may use SQLite | |
4924 ** memory allocation for a fast or recursive mutex. | |
4925 ** | |
4926 ** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is | |
4927 ** called, but only if the prior call to xMutexInit returned SQLITE_OK. | |
4928 ** If xMutexInit fails in any way, it is expected to clean up after itself | |
4929 ** prior to returning. | |
4930 */ | |
4931 typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; | |
4932 struct sqlite3_mutex_methods { | |
4933 int (*xMutexInit)(void); | |
4934 int (*xMutexEnd)(void); | |
4935 sqlite3_mutex *(*xMutexAlloc)(int); | |
4936 void (*xMutexFree)(sqlite3_mutex *); | |
4937 void (*xMutexEnter)(sqlite3_mutex *); | |
4938 int (*xMutexTry)(sqlite3_mutex *); | |
4939 void (*xMutexLeave)(sqlite3_mutex *); | |
4940 int (*xMutexHeld)(sqlite3_mutex *); | |
4941 int (*xMutexNotheld)(sqlite3_mutex *); | |
4942 }; | |
4943 | |
4944 /* | |
4945 ** CAPI3REF: Mutex Verification Routines | |
4946 ** | |
4947 ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines | |
4948 ** are intended for use inside assert() statements. ^The SQLite core | |
4949 ** never uses these routines except inside an assert() and applications | |
4950 ** are advised to follow the lead of the core. ^The SQLite core only | |
4951 ** provides implementations for these routines when it is compiled | |
4952 ** with the SQLITE_DEBUG flag. ^External mutex implementations | |
4953 ** are only required to provide these routines if SQLITE_DEBUG is | |
4954 ** defined and if NDEBUG is not defined. | |
4955 ** | |
4956 ** ^These routines should return true if the mutex in their argument | |
4957 ** is held or not held, respectively, by the calling thread. | |
4958 ** | |
4959 ** ^The implementation is not required to provided versions of these | |
4960 ** routines that actually work. If the implementation does not provide working | |
4961 ** versions of these routines, it should at least provide stubs that always | |
4962 ** return true so that one does not get spurious assertion failures. | |
4963 ** | |
4964 ** ^If the argument to sqlite3_mutex_held() is a NULL pointer then | |
4965 ** the routine should return 1. This seems counter-intuitive since | |
4966 ** clearly the mutex cannot be held if it does not exist. But the | |
4967 ** the reason the mutex does not exist is because the build is not | |
4968 ** using mutexes. And we do not want the assert() containing the | |
4969 ** call to sqlite3_mutex_held() to fail, so a non-zero return is | |
4970 ** the appropriate thing to do. ^The sqlite3_mutex_notheld() | |
4971 ** interface should also return 1 when given a NULL pointer. | |
4972 */ | |
4973 #ifndef NDEBUG | |
4974 SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*); | |
4975 SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*); | |
4976 #endif | |
4977 | |
4978 /* | |
4979 ** CAPI3REF: Mutex Types | |
4980 ** | |
4981 ** The [sqlite3_mutex_alloc()] interface takes a single argument | |
4982 ** which is one of these integer constants. | |
4983 ** | |
4984 ** The set of static mutexes may change from one SQLite release to the | |
4985 ** next. Applications that override the built-in mutex logic must be | |
4986 ** prepared to accommodate additional static mutexes. | |
4987 */ | |
4988 #define SQLITE_MUTEX_FAST 0 | |
4989 #define SQLITE_MUTEX_RECURSIVE 1 | |
4990 #define SQLITE_MUTEX_STATIC_MASTER 2 | |
4991 #define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ | |
4992 #define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ | |
4993 #define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ | |
4994 #define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ | |
4995 #define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ | |
4996 #define SQLITE_MUTEX_STATIC_LRU2 7 /* lru page list */ | |
4997 | |
4998 /* | |
4999 ** CAPI3REF: Retrieve the mutex for a database connection | |
5000 ** | |
5001 ** ^This interface returns a pointer the [sqlite3_mutex] object that | |
5002 ** serializes access to the [database connection] given in the argument | |
5003 ** when the [threading mode] is Serialized. | |
5004 ** ^If the [threading mode] is Single-thread or Multi-thread then this | |
5005 ** routine returns a NULL pointer. | |
5006 */ | |
5007 SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*); | |
5008 | |
5009 /* | |
5010 ** CAPI3REF: Low-Level Control Of Database Files | |
5011 ** | |
5012 ** ^The [sqlite3_file_control()] interface makes a direct call to the | |
5013 ** xFileControl method for the [sqlite3_io_methods] object associated | |
5014 ** with a particular database identified by the second argument. ^The | |
5015 ** name of the database "main" for the main database or "temp" for the | |
5016 ** TEMP database, or the name that appears after the AS keyword for | |
5017 ** databases that are added using the [ATTACH] SQL command. | |
5018 ** ^A NULL pointer can be used in place of "main" to refer to the | |
5019 ** main database file. | |
5020 ** ^The third and fourth parameters to this routine | |
5021 ** are passed directly through to the second and third parameters of | |
5022 ** the xFileControl method. ^The return value of the xFileControl | |
5023 ** method becomes the return value of this routine. | |
5024 ** | |
5025 ** ^If the second parameter (zDbName) does not match the name of any | |
5026 ** open database file, then SQLITE_ERROR is returned. ^This error | |
5027 ** code is not remembered and will not be recalled by [sqlite3_errcode()] | |
5028 ** or [sqlite3_errmsg()]. The underlying xFileControl method might | |
5029 ** also return SQLITE_ERROR. There is no way to distinguish between | |
5030 ** an incorrect zDbName and an SQLITE_ERROR return from the underlying | |
5031 ** xFileControl method. | |
5032 ** | |
5033 ** See also: [SQLITE_FCNTL_LOCKSTATE] | |
5034 */ | |
5035 SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); | |
5036 | |
5037 /* | |
5038 ** CAPI3REF: Testing Interface | |
5039 ** | |
5040 ** ^The sqlite3_test_control() interface is used to read out internal | |
5041 ** state of SQLite and to inject faults into SQLite for testing | |
5042 ** purposes. ^The first parameter is an operation code that determines | |
5043 ** the number, meaning, and operation of all subsequent parameters. | |
5044 ** | |
5045 ** This interface is not for use by applications. It exists solely | |
5046 ** for verifying the correct operation of the SQLite library. Depending | |
5047 ** on how the SQLite library is compiled, this interface might not exist. | |
5048 ** | |
5049 ** The details of the operation codes, their meanings, the parameters | |
5050 ** they take, and what they do are all subject to change without notice. | |
5051 ** Unlike most of the SQLite API, this function is not guaranteed to | |
5052 ** operate consistently from one release to the next. | |
5053 */ | |
5054 SQLITE_API int sqlite3_test_control(int op, ...); | |
5055 | |
5056 /* | |
5057 ** CAPI3REF: Testing Interface Operation Codes | |
5058 ** | |
5059 ** These constants are the valid operation code parameters used | |
5060 ** as the first argument to [sqlite3_test_control()]. | |
5061 ** | |
5062 ** These parameters and their meanings are subject to change | |
5063 ** without notice. These values are for testing purposes only. | |
5064 ** Applications should not use any of these parameters or the | |
5065 ** [sqlite3_test_control()] interface. | |
5066 */ | |
5067 #define SQLITE_TESTCTRL_FIRST 5 | |
5068 #define SQLITE_TESTCTRL_PRNG_SAVE 5 | |
5069 #define SQLITE_TESTCTRL_PRNG_RESTORE 6 | |
5070 #define SQLITE_TESTCTRL_PRNG_RESET 7 | |
5071 #define SQLITE_TESTCTRL_BITVEC_TEST 8 | |
5072 #define SQLITE_TESTCTRL_FAULT_INSTALL 9 | |
5073 #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 | |
5074 #define SQLITE_TESTCTRL_PENDING_BYTE 11 | |
5075 #define SQLITE_TESTCTRL_ASSERT 12 | |
5076 #define SQLITE_TESTCTRL_ALWAYS 13 | |
5077 #define SQLITE_TESTCTRL_RESERVE 14 | |
5078 #define SQLITE_TESTCTRL_OPTIMIZATIONS 15 | |
5079 #define SQLITE_TESTCTRL_ISKEYWORD 16 | |
5080 #define SQLITE_TESTCTRL_PGHDRSZ 17 | |
5081 #define SQLITE_TESTCTRL_LAST 17 | |
5082 | |
5083 /* | |
5084 ** CAPI3REF: SQLite Runtime Status | |
5085 ** | |
5086 ** ^This interface is used to retrieve runtime status information | |
5087 ** about the preformance of SQLite, and optionally to reset various | |
5088 ** highwater marks. ^The first argument is an integer code for | |
5089 ** the specific parameter to measure. ^(Recognized integer codes | |
5090 ** are of the form [SQLITE_STATUS_MEMORY_USED | SQLITE_STATUS_...].)^ | |
5091 ** ^The current value of the parameter is returned into *pCurrent. | |
5092 ** ^The highest recorded value is returned in *pHighwater. ^If the | |
5093 ** resetFlag is true, then the highest record value is reset after | |
5094 ** *pHighwater is written. ^(Some parameters do not record the highest | |
5095 ** value. For those parameters | |
5096 ** nothing is written into *pHighwater and the resetFlag is ignored.)^ | |
5097 ** ^(Other parameters record only the highwater mark and not the current | |
5098 ** value. For these latter parameters nothing is written into *pCurrent.)^ | |
5099 ** | |
5100 ** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a | |
5101 ** non-zero [error code] on failure. | |
5102 ** | |
5103 ** This routine is threadsafe but is not atomic. This routine can be | |
5104 ** called while other threads are running the same or different SQLite | |
5105 ** interfaces. However the values returned in *pCurrent and | |
5106 ** *pHighwater reflect the status of SQLite at different points in time | |
5107 ** and it is possible that another thread might change the parameter | |
5108 ** in between the times when *pCurrent and *pHighwater are written. | |
5109 ** | |
5110 ** See also: [sqlite3_db_status()] | |
5111 */ | |
5112 SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); | |
5113 | |
5114 | |
5115 /* | |
5116 ** CAPI3REF: Status Parameters | |
5117 ** | |
5118 ** These integer constants designate various run-time status parameters | |
5119 ** that can be returned by [sqlite3_status()]. | |
5120 ** | |
5121 ** <dl> | |
5122 ** ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> | |
5123 ** <dd>This parameter is the current amount of memory checked out | |
5124 ** using [sqlite3_malloc()], either directly or indirectly. The | |
5125 ** figure includes calls made to [sqlite3_malloc()] by the application | |
5126 ** and internal memory usage by the SQLite library. Scratch memory | |
5127 ** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache | |
5128 ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in | |
5129 ** this parameter. The amount returned is the sum of the allocation | |
5130 ** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ | |
5131 ** | |
5132 ** ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> | |
5133 ** <dd>This parameter records the largest memory allocation request | |
5134 ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their | |
5135 ** internal equivalents). Only the value returned in the | |
5136 ** *pHighwater parameter to [sqlite3_status()] is of interest. | |
5137 ** The value written into the *pCurrent parameter is undefined.</dd>)^ | |
5138 ** | |
5139 ** ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> | |
5140 ** <dd>This parameter returns the number of pages used out of the | |
5141 ** [pagecache memory allocator] that was configured using | |
5142 ** [SQLITE_CONFIG_PAGECACHE]. The | |
5143 ** value returned is in pages, not in bytes.</dd>)^ | |
5144 ** | |
5145 ** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> | |
5146 ** <dd>This parameter returns the number of bytes of page cache | |
5147 ** allocation which could not be statisfied by the [SQLITE_CONFIG_PAGECACHE] | |
5148 ** buffer and where forced to overflow to [sqlite3_malloc()]. The | |
5149 ** returned value includes allocations that overflowed because they | |
5150 ** where too large (they were larger than the "sz" parameter to | |
5151 ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because | |
5152 ** no space was left in the page cache.</dd>)^ | |
5153 ** | |
5154 ** ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> | |
5155 ** <dd>This parameter records the largest memory allocation request | |
5156 ** handed to [pagecache memory allocator]. Only the value returned in the | |
5157 ** *pHighwater parameter to [sqlite3_status()] is of interest. | |
5158 ** The value written into the *pCurrent parameter is undefined.</dd>)^ | |
5159 ** | |
5160 ** ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt> | |
5161 ** <dd>This parameter returns the number of allocations used out of the | |
5162 ** [scratch memory allocator] configured using | |
5163 ** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not | |
5164 ** in bytes. Since a single thread may only have one scratch allocation | |
5165 ** outstanding at time, this parameter also reports the number of threads | |
5166 ** using scratch memory at the same time.</dd>)^ | |
5167 ** | |
5168 ** ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> | |
5169 ** <dd>This parameter returns the number of bytes of scratch memory | |
5170 ** allocation which could not be statisfied by the [SQLITE_CONFIG_SCRATCH] | |
5171 ** buffer and where forced to overflow to [sqlite3_malloc()]. The values | |
5172 ** returned include overflows because the requested allocation was too | |
5173 ** larger (that is, because the requested allocation was larger than the | |
5174 ** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer | |
5175 ** slots were available. | |
5176 ** </dd>)^ | |
5177 ** | |
5178 ** ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt> | |
5179 ** <dd>This parameter records the largest memory allocation request | |
5180 ** handed to [scratch memory allocator]. Only the value returned in the | |
5181 ** *pHighwater parameter to [sqlite3_status()] is of interest. | |
5182 ** The value written into the *pCurrent parameter is undefined.</dd>)^ | |
5183 ** | |
5184 ** ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> | |
5185 ** <dd>This parameter records the deepest parser stack. It is only | |
5186 ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ | |
5187 ** </dl> | |
5188 ** | |
5189 ** New status parameters may be added from time to time. | |
5190 */ | |
5191 #define SQLITE_STATUS_MEMORY_USED 0 | |
5192 #define SQLITE_STATUS_PAGECACHE_USED 1 | |
5193 #define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 | |
5194 #define SQLITE_STATUS_SCRATCH_USED 3 | |
5195 #define SQLITE_STATUS_SCRATCH_OVERFLOW 4 | |
5196 #define SQLITE_STATUS_MALLOC_SIZE 5 | |
5197 #define SQLITE_STATUS_PARSER_STACK 6 | |
5198 #define SQLITE_STATUS_PAGECACHE_SIZE 7 | |
5199 #define SQLITE_STATUS_SCRATCH_SIZE 8 | |
5200 | |
5201 /* | |
5202 ** CAPI3REF: Database Connection Status | |
5203 ** | |
5204 ** ^This interface is used to retrieve runtime status information | |
5205 ** about a single [database connection]. ^The first argument is the | |
5206 ** database connection object to be interrogated. ^The second argument | |
5207 ** is an integer constant, taken from the set of | |
5208 ** [SQLITE_DBSTATUS_LOOKASIDE_USED | SQLITE_DBSTATUS_*] macros, that | |
5209 ** determiness the parameter to interrogate. The set of | |
5210 ** [SQLITE_DBSTATUS_LOOKASIDE_USED | SQLITE_DBSTATUS_*] macros is likely | |
5211 ** to grow in future releases of SQLite. | |
5212 ** | |
5213 ** ^The current value of the requested parameter is written into *pCur | |
5214 ** and the highest instantaneous value is written into *pHiwtr. ^If | |
5215 ** the resetFlg is true, then the highest instantaneous value is | |
5216 ** reset back down to the current value. | |
5217 ** | |
5218 ** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. | |
5219 */ | |
5220 SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); | |
5221 | |
5222 /* | |
5223 ** CAPI3REF: Status Parameters for database connections | |
5224 ** | |
5225 ** These constants are the available integer "verbs" that can be passed as | |
5226 ** the second argument to the [sqlite3_db_status()] interface. | |
5227 ** | |
5228 ** New verbs may be added in future releases of SQLite. Existing verbs | |
5229 ** might be discontinued. Applications should check the return code from | |
5230 ** [sqlite3_db_status()] to make sure that the call worked. | |
5231 ** The [sqlite3_db_status()] interface will return a non-zero error code | |
5232 ** if a discontinued or unsupported verb is invoked. | |
5233 ** | |
5234 ** <dl> | |
5235 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> | |
5236 ** <dd>This parameter returns the number of lookaside memory slots currently | |
5237 ** checked out.</dd>)^ | |
5238 ** | |
5239 ** <dt>SQLITE_DBSTATUS_CACHE_USED</dt> | |
5240 ** <dd>^This parameter returns the approximate number of of bytes of heap | |
5241 ** memory used by all pager caches associated with the database connection. | |
5242 ** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. | |
5243 ** </dd> | |
5244 ** </dl> | |
5245 */ | |
5246 #define SQLITE_DBSTATUS_LOOKASIDE_USED 0 | |
5247 #define SQLITE_DBSTATUS_CACHE_USED 1 | |
5248 #define SQLITE_DBSTATUS_MAX 1 /* Largest defined DBSTATUS */ | |
5249 | |
5250 | |
5251 /* | |
5252 ** CAPI3REF: Prepared Statement Status | |
5253 ** | |
5254 ** ^(Each prepared statement maintains various | |
5255 ** [SQLITE_STMTSTATUS_SORT | counters] that measure the number | |
5256 ** of times it has performed specific operations.)^ These counters can | |
5257 ** be used to monitor the performance characteristics of the prepared | |
5258 ** statements. For example, if the number of table steps greatly exceeds | |
5259 ** the number of table searches or result rows, that would tend to indicate | |
5260 ** that the prepared statement is using a full table scan rather than | |
5261 ** an index. | |
5262 ** | |
5263 ** ^(This interface is used to retrieve and reset counter values from | |
5264 ** a [prepared statement]. The first argument is the prepared statement | |
5265 ** object to be interrogated. The second argument | |
5266 ** is an integer code for a specific [SQLITE_STMTSTATUS_SORT | counter] | |
5267 ** to be interrogated.)^ | |
5268 ** ^The current value of the requested counter is returned. | |
5269 ** ^If the resetFlg is true, then the counter is reset to zero after this | |
5270 ** interface call returns. | |
5271 ** | |
5272 ** See also: [sqlite3_status()] and [sqlite3_db_status()]. | |
5273 */ | |
5274 SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); | |
5275 | |
5276 /* | |
5277 ** CAPI3REF: Status Parameters for prepared statements | |
5278 ** | |
5279 ** These preprocessor macros define integer codes that name counter | |
5280 ** values associated with the [sqlite3_stmt_status()] interface. | |
5281 ** The meanings of the various counters are as follows: | |
5282 ** | |
5283 ** <dl> | |
5284 ** <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> | |
5285 ** <dd>^This is the number of times that SQLite has stepped forward in | |
5286 ** a table as part of a full table scan. Large numbers for this counter | |
5287 ** may indicate opportunities for performance improvement through | |
5288 ** careful use of indices.</dd> | |
5289 ** | |
5290 ** <dt>SQLITE_STMTSTATUS_SORT</dt> | |
5291 ** <dd>^This is the number of sort operations that have occurred. | |
5292 ** A non-zero value in this counter may indicate an opportunity to | |
5293 ** improvement performance through careful use of indices.</dd> | |
5294 ** | |
5295 ** <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> | |
5296 ** <dd>^This is the number of rows inserted into transient indices that | |
5297 ** were created automatically in order to help joins run faster. | |
5298 ** A non-zero value in this counter may indicate an opportunity to | |
5299 ** improvement performance by adding permanent indices that do not | |
5300 ** need to be reinitialized each time the statement is run.</dd> | |
5301 ** | |
5302 ** </dl> | |
5303 */ | |
5304 #define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 | |
5305 #define SQLITE_STMTSTATUS_SORT 2 | |
5306 #define SQLITE_STMTSTATUS_AUTOINDEX 3 | |
5307 | |
5308 /* | |
5309 ** CAPI3REF: Custom Page Cache Object | |
5310 ** | |
5311 ** The sqlite3_pcache type is opaque. It is implemented by | |
5312 ** the pluggable module. The SQLite core has no knowledge of | |
5313 ** its size or internal structure and never deals with the | |
5314 ** sqlite3_pcache object except by holding and passing pointers | |
5315 ** to the object. | |
5316 ** | |
5317 ** See [sqlite3_pcache_methods] for additional information. | |
5318 */ | |
5319 typedef struct sqlite3_pcache sqlite3_pcache; | |
5320 | |
5321 /* | |
5322 ** CAPI3REF: Application Defined Page Cache. | |
5323 ** KEYWORDS: {page cache} | |
5324 ** | |
5325 ** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE], ...) interface can | |
5326 ** register an alternative page cache implementation by passing in an | |
5327 ** instance of the sqlite3_pcache_methods structure.)^ The majority of the | |
5328 ** heap memory used by SQLite is used by the page cache to cache data read | |
5329 ** from, or ready to be written to, the database file. By implementing a | |
5330 ** custom page cache using this API, an application can control more | |
5331 ** precisely the amount of memory consumed by SQLite, the way in which | |
5332 ** that memory is allocated and released, and the policies used to | |
5333 ** determine exactly which parts of a database file are cached and for | |
5334 ** how long. | |
5335 ** | |
5336 ** ^(The contents of the sqlite3_pcache_methods structure are copied to an | |
5337 ** internal buffer by SQLite within the call to [sqlite3_config]. Hence | |
5338 ** the application may discard the parameter after the call to | |
5339 ** [sqlite3_config()] returns.)^ | |
5340 ** | |
5341 ** ^The xInit() method is called once for each call to [sqlite3_initialize()] | |
5342 ** (usually only once during the lifetime of the process). ^(The xInit() | |
5343 ** method is passed a copy of the sqlite3_pcache_methods.pArg value.)^ | |
5344 ** ^The xInit() method can set up up global structures and/or any mutexes | |
5345 ** required by the custom page cache implementation. | |
5346 ** | |
5347 ** ^The xShutdown() method is called from within [sqlite3_shutdown()], | |
5348 ** if the application invokes this API. It can be used to clean up | |
5349 ** any outstanding resources before process shutdown, if required. | |
5350 ** | |
5351 ** ^SQLite holds a [SQLITE_MUTEX_RECURSIVE] mutex when it invokes | |
5352 ** the xInit method, so the xInit method need not be threadsafe. ^The | |
5353 ** xShutdown method is only called from [sqlite3_shutdown()] so it does | |
5354 ** not need to be threadsafe either. All other methods must be threadsafe | |
5355 ** in multithreaded applications. | |
5356 ** | |
5357 ** ^SQLite will never invoke xInit() more than once without an intervening | |
5358 ** call to xShutdown(). | |
5359 ** | |
5360 ** ^The xCreate() method is used to construct a new cache instance. SQLite | |
5361 ** will typically create one cache instance for each open database file, | |
5362 ** though this is not guaranteed. ^The | |
5363 ** first parameter, szPage, is the size in bytes of the pages that must | |
5364 ** be allocated by the cache. ^szPage will not be a power of two. ^szPage | |
5365 ** will the page size of the database file that is to be cached plus an | |
5366 ** increment (here called "R") of about 100 or 200. ^SQLite will use the | |
5367 ** extra R bytes on each page to store metadata about the underlying | |
5368 ** database page on disk. The value of R depends | |
5369 ** on the SQLite version, the target platform, and how SQLite was compiled. | |
5370 ** ^R is constant for a particular build of SQLite. ^The second argument to | |
5371 ** xCreate(), bPurgeable, is true if the cache being created will | |
5372 ** be used to cache database pages of a file stored on disk, or | |
5373 ** false if it is used for an in-memory database. ^The cache implementation | |
5374 ** does not have to do anything special based with the value of bPurgeable; | |
5375 ** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will | |
5376 ** never invoke xUnpin() except to deliberately delete a page. | |
5377 ** ^In other words, a cache created with bPurgeable set to false will | |
5378 ** never contain any unpinned pages. | |
5379 ** | |
5380 ** ^(The xCachesize() method may be called at any time by SQLite to set the | |
5381 ** suggested maximum cache-size (number of pages stored by) the cache | |
5382 ** instance passed as the first argument. This is the value configured using | |
5383 ** the SQLite "[PRAGMA cache_size]" command.)^ ^As with the bPurgeable | |
5384 ** parameter, the implementation is not required to do anything with this | |
5385 ** value; it is advisory only. | |
5386 ** | |
5387 ** ^The xPagecount() method should return the number of pages currently | |
5388 ** stored in the cache. | |
5389 ** | |
5390 ** ^The xFetch() method is used to fetch a page and return a pointer to it. | |
5391 ** ^A 'page', in this context, is a buffer of szPage bytes aligned at an | |
5392 ** 8-byte boundary. ^The page to be fetched is determined by the key. ^The | |
5393 ** mimimum key value is 1. After it has been retrieved using xFetch, the page | |
5394 ** is considered to be "pinned". | |
5395 ** | |
5396 ** ^If the requested page is already in the page cache, then the page cache | |
5397 ** implementation must return a pointer to the page buffer with its content | |
5398 ** intact. ^(If the requested page is not already in the cache, then the | |
5399 ** behavior of the cache implementation is determined by the value of the | |
5400 ** createFlag parameter passed to xFetch, according to the following table: | |
5401 ** | |
5402 ** <table border=1 width=85% align=center> | |
5403 ** <tr><th> createFlag <th> Behaviour when page is not already in cache | |
5404 ** <tr><td> 0 <td> Do not allocate a new page. Return NULL. | |
5405 ** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. | |
5406 ** Otherwise return NULL. | |
5407 ** <tr><td> 2 <td> Make every effort to allocate a new page. Only return | |
5408 ** NULL if allocating a new page is effectively impossible. | |
5409 ** </table>)^ | |
5410 ** | |
5411 ** SQLite will normally invoke xFetch() with a createFlag of 0 or 1. If | |
5412 ** a call to xFetch() with createFlag==1 returns NULL, then SQLite will | |
5413 ** attempt to unpin one or more cache pages by spilling the content of | |
5414 ** pinned pages to disk and synching the operating system disk cache. After | |
5415 ** attempting to unpin pages, the xFetch() method will be invoked again with | |
5416 ** a createFlag of 2. | |
5417 ** | |
5418 ** ^xUnpin() is called by SQLite with a pointer to a currently pinned page | |
5419 ** as its second argument. ^(If the third parameter, discard, is non-zero, | |
5420 ** then the page should be evicted from the cache. In this case SQLite | |
5421 ** assumes that the next time the page is retrieved from the cache using | |
5422 ** the xFetch() method, it will be zeroed.)^ ^If the discard parameter is | |
5423 ** zero, then the page is considered to be unpinned. ^The cache implementation | |
5424 ** may choose to evict unpinned pages at any time. | |
5425 ** | |
5426 ** ^(The cache is not required to perform any reference counting. A single | |
5427 ** call to xUnpin() unpins the page regardless of the number of prior calls | |
5428 ** to xFetch().)^ | |
5429 ** | |
5430 ** ^The xRekey() method is used to change the key value associated with the | |
5431 ** page passed as the second argument from oldKey to newKey. ^If the cache | |
5432 ** previously contains an entry associated with newKey, it should be | |
5433 ** discarded. ^Any prior cache entry associated with newKey is guaranteed not | |
5434 ** to be pinned. | |
5435 ** | |
5436 ** ^When SQLite calls the xTruncate() method, the cache must discard all | |
5437 ** existing cache entries with page numbers (keys) greater than or equal | |
5438 ** to the value of the iLimit parameter passed to xTruncate(). ^If any | |
5439 ** of these pages are pinned, they are implicitly unpinned, meaning that | |
5440 ** they can be safely discarded. | |
5441 ** | |
5442 ** ^The xDestroy() method is used to delete a cache allocated by xCreate(). | |
5443 ** All resources associated with the specified cache should be freed. ^After | |
5444 ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] | |
5445 ** handle invalid, and will not use it with any other sqlite3_pcache_methods | |
5446 ** functions. | |
5447 */ | |
5448 typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; | |
5449 struct sqlite3_pcache_methods { | |
5450 void *pArg; | |
5451 int (*xInit)(void*); | |
5452 void (*xShutdown)(void*); | |
5453 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); | |
5454 void (*xCachesize)(sqlite3_pcache*, int nCachesize); | |
5455 int (*xPagecount)(sqlite3_pcache*); | |
5456 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); | |
5457 void (*xUnpin)(sqlite3_pcache*, void*, int discard); | |
5458 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); | |
5459 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); | |
5460 void (*xDestroy)(sqlite3_pcache*); | |
5461 }; | |
5462 | |
5463 /* | |
5464 ** CAPI3REF: Online Backup Object | |
5465 ** | |
5466 ** The sqlite3_backup object records state information about an ongoing | |
5467 ** online backup operation. ^The sqlite3_backup object is created by | |
5468 ** a call to [sqlite3_backup_init()] and is destroyed by a call to | |
5469 ** [sqlite3_backup_finish()]. | |
5470 ** | |
5471 ** See Also: [Using the SQLite Online Backup API] | |
5472 */ | |
5473 typedef struct sqlite3_backup sqlite3_backup; | |
5474 | |
5475 /* | |
5476 ** CAPI3REF: Online Backup API. | |
5477 ** | |
5478 ** The backup API copies the content of one database into another. | |
5479 ** It is useful either for creating backups of databases or | |
5480 ** for copying in-memory databases to or from persistent files. | |
5481 ** | |
5482 ** See Also: [Using the SQLite Online Backup API] | |
5483 ** | |
5484 ** ^Exclusive access is required to the destination database for the | |
5485 ** duration of the operation. ^However the source database is only | |
5486 ** read-locked while it is actually being read; it is not locked | |
5487 ** continuously for the entire backup operation. ^Thus, the backup may be | |
5488 ** performed on a live source database without preventing other users from | |
5489 ** reading or writing to the source database while the backup is underway. | |
5490 ** | |
5491 ** ^(To perform a backup operation: | |
5492 ** <ol> | |
5493 ** <li><b>sqlite3_backup_init()</b> is called once to initialize the | |
5494 ** backup, | |
5495 ** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer | |
5496 ** the data between the two databases, and finally | |
5497 ** <li><b>sqlite3_backup_finish()</b> is called to release all resources | |
5498 ** associated with the backup operation. | |
5499 ** </ol>)^ | |
5500 ** There should be exactly one call to sqlite3_backup_finish() for each | |
5501 ** successful call to sqlite3_backup_init(). | |
5502 ** | |
5503 ** <b>sqlite3_backup_init()</b> | |
5504 ** | |
5505 ** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the | |
5506 ** [database connection] associated with the destination database | |
5507 ** and the database name, respectively. | |
5508 ** ^The database name is "main" for the main database, "temp" for the | |
5509 ** temporary database, or the name specified after the AS keyword in | |
5510 ** an [ATTACH] statement for an attached database. | |
5511 ** ^The S and M arguments passed to | |
5512 ** sqlite3_backup_init(D,N,S,M) identify the [database connection] | |
5513 ** and database name of the source database, respectively. | |
5514 ** ^The source and destination [database connections] (parameters S and D) | |
5515 ** must be different or else sqlite3_backup_init(D,N,S,M) will file with | |
5516 ** an error. | |
5517 ** | |
5518 ** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is | |
5519 ** returned and an error code and error message are store3d in the | |
5520 ** destination [database connection] D. | |
5521 ** ^The error code and message for the failed call to sqlite3_backup_init() | |
5522 ** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or | |
5523 ** [sqlite3_errmsg16()] functions. | |
5524 ** ^A successful call to sqlite3_backup_init() returns a pointer to an | |
5525 ** [sqlite3_backup] object. | |
5526 ** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and | |
5527 ** sqlite3_backup_finish() functions to perform the specified backup | |
5528 ** operation. | |
5529 ** | |
5530 ** <b>sqlite3_backup_step()</b> | |
5531 ** | |
5532 ** ^Function sqlite3_backup_step(B,N) will copy up to N pages between | |
5533 ** the source and destination databases specified by [sqlite3_backup] object B. | |
5534 ** ^If N is negative, all remaining source pages are copied. | |
5535 ** ^If sqlite3_backup_step(B,N) successfully copies N pages and there | |
5536 ** are still more pages to be copied, then the function resturns [SQLITE_OK]. | |
5537 ** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages | |
5538 ** from source to destination, then it returns [SQLITE_DONE]. | |
5539 ** ^If an error occurs while running sqlite3_backup_step(B,N), | |
5540 ** then an [error code] is returned. ^As well as [SQLITE_OK] and | |
5541 ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], | |
5542 ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an | |
5543 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. | |
5544 ** | |
5545 ** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if | |
5546 ** <ol> | |
5547 ** <li> the destination database was opened read-only, or | |
5548 ** <li> the destination database is using write-ahead-log journaling | |
5549 ** and the destination and source page sizes differ, or | |
5550 ** <li> The destination database is an in-memory database and the | |
5551 ** destination and source page sizes differ. | |
5552 ** </ol>)^ | |
5553 ** | |
5554 ** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then | |
5555 ** the [sqlite3_busy_handler | busy-handler function] | |
5556 ** is invoked (if one is specified). ^If the | |
5557 ** busy-handler returns non-zero before the lock is available, then | |
5558 ** [SQLITE_BUSY] is returned to the caller. ^In this case the call to | |
5559 ** sqlite3_backup_step() can be retried later. ^If the source | |
5560 ** [database connection] | |
5561 ** is being used to write to the source database when sqlite3_backup_step() | |
5562 ** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this | |
5563 ** case the call to sqlite3_backup_step() can be retried later on. ^(If | |
5564 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or | |
5565 ** [SQLITE_READONLY] is returned, then | |
5566 ** there is no point in retrying the call to sqlite3_backup_step(). These | |
5567 ** errors are considered fatal.)^ The application must accept | |
5568 ** that the backup operation has failed and pass the backup operation handle | |
5569 ** to the sqlite3_backup_finish() to release associated resources. | |
5570 ** | |
5571 ** ^The first call to sqlite3_backup_step() obtains an exclusive lock | |
5572 ** on the destination file. ^The exclusive lock is not released until either | |
5573 ** sqlite3_backup_finish() is called or the backup operation is complete | |
5574 ** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to | |
5575 ** sqlite3_backup_step() obtains a [shared lock] on the source database that | |
5576 ** lasts for the duration of the sqlite3_backup_step() call. | |
5577 ** ^Because the source database is not locked between calls to | |
5578 ** sqlite3_backup_step(), the source database may be modified mid-way | |
5579 ** through the backup process. ^If the source database is modified by an | |
5580 ** external process or via a database connection other than the one being | |
5581 ** used by the backup operation, then the backup will be automatically | |
5582 ** restarted by the next call to sqlite3_backup_step(). ^If the source | |
5583 ** database is modified by the using the same database connection as is used | |
5584 ** by the backup operation, then the backup database is automatically | |
5585 ** updated at the same time. | |
5586 ** | |
5587 ** <b>sqlite3_backup_finish()</b> | |
5588 ** | |
5589 ** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the | |
5590 ** application wishes to abandon the backup operation, the application | |
5591 ** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). | |
5592 ** ^The sqlite3_backup_finish() interfaces releases all | |
5593 ** resources associated with the [sqlite3_backup] object. | |
5594 ** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any | |
5595 ** active write-transaction on the destination database is rolled back. | |
5596 ** The [sqlite3_backup] object is invalid | |
5597 ** and may not be used following a call to sqlite3_backup_finish(). | |
5598 ** | |
5599 ** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no | |
5600 ** sqlite3_backup_step() errors occurred, regardless or whether or not | |
5601 ** sqlite3_backup_step() completed. | |
5602 ** ^If an out-of-memory condition or IO error occurred during any prior | |
5603 ** sqlite3_backup_step() call on the same [sqlite3_backup] object, then | |
5604 ** sqlite3_backup_finish() returns the corresponding [error code]. | |
5605 ** | |
5606 ** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() | |
5607 ** is not a permanent error and does not affect the return value of | |
5608 ** sqlite3_backup_finish(). | |
5609 ** | |
5610 ** <b>sqlite3_backup_remaining(), sqlite3_backup_pagecount()</b> | |
5611 ** | |
5612 ** ^Each call to sqlite3_backup_step() sets two values inside | |
5613 ** the [sqlite3_backup] object: the number of pages still to be backed | |
5614 ** up and the total number of pages in the source databae file. | |
5615 ** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces | |
5616 ** retrieve these two values, respectively. | |
5617 ** | |
5618 ** ^The values returned by these functions are only updated by | |
5619 ** sqlite3_backup_step(). ^If the source database is modified during a backup | |
5620 ** operation, then the values are not updated to account for any extra | |
5621 ** pages that need to be updated or the size of the source database file | |
5622 ** changing. | |
5623 ** | |
5624 ** <b>Concurrent Usage of Database Handles</b> | |
5625 ** | |
5626 ** ^The source [database connection] may be used by the application for other | |
5627 ** purposes while a backup operation is underway or being initialized. | |
5628 ** ^If SQLite is compiled and configured to support threadsafe database | |
5629 ** connections, then the source database connection may be used concurrently | |
5630 ** from within other threads. | |
5631 ** | |
5632 ** However, the application must guarantee that the destination | |
5633 ** [database connection] is not passed to any other API (by any thread) after | |
5634 ** sqlite3_backup_init() is called and before the corresponding call to | |
5635 ** sqlite3_backup_finish(). SQLite does not currently check to see | |
5636 ** if the application incorrectly accesses the destination [database connection] | |
5637 ** and so no error code is reported, but the operations may malfunction | |
5638 ** nevertheless. Use of the destination database connection while a | |
5639 ** backup is in progress might also also cause a mutex deadlock. | |
5640 ** | |
5641 ** If running in [shared cache mode], the application must | |
5642 ** guarantee that the shared cache used by the destination database | |
5643 ** is not accessed while the backup is running. In practice this means | |
5644 ** that the application must guarantee that the disk file being | |
5645 ** backed up to is not accessed by any connection within the process, | |
5646 ** not just the specific connection that was passed to sqlite3_backup_init(). | |
5647 ** | |
5648 ** The [sqlite3_backup] object itself is partially threadsafe. Multiple | |
5649 ** threads may safely make multiple concurrent calls to sqlite3_backup_step(). | |
5650 ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() | |
5651 ** APIs are not strictly speaking threadsafe. If they are invoked at the | |
5652 ** same time as another thread is invoking sqlite3_backup_step() it is | |
5653 ** possible that they return invalid values. | |
5654 */ | |
5655 SQLITE_API sqlite3_backup *sqlite3_backup_init( | |
5656 sqlite3 *pDest, /* Destination database handle */ | |
5657 const char *zDestName, /* Destination database name */ | |
5658 sqlite3 *pSource, /* Source database handle */ | |
5659 const char *zSourceName /* Source database name */ | |
5660 ); | |
5661 SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage); | |
5662 SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p); | |
5663 SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p); | |
5664 SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p); | |
5665 | |
5666 /* | |
5667 ** CAPI3REF: Unlock Notification | |
5668 ** | |
5669 ** ^When running in shared-cache mode, a database operation may fail with | |
5670 ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or | |
5671 ** individual tables within the shared-cache cannot be obtained. See | |
5672 ** [SQLite Shared-Cache Mode] for a description of shared-cache locking. | |
5673 ** ^This API may be used to register a callback that SQLite will invoke | |
5674 ** when the connection currently holding the required lock relinquishes it. | |
5675 ** ^This API is only available if the library was compiled with the | |
5676 ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. | |
5677 ** | |
5678 ** See Also: [Using the SQLite Unlock Notification Feature]. | |
5679 ** | |
5680 ** ^Shared-cache locks are released when a database connection concludes | |
5681 ** its current transaction, either by committing it or rolling it back. | |
5682 ** | |
5683 ** ^When a connection (known as the blocked connection) fails to obtain a | |
5684 ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the | |
5685 ** identity of the database connection (the blocking connection) that | |
5686 ** has locked the required resource is stored internally. ^After an | |
5687 ** application receives an SQLITE_LOCKED error, it may call the | |
5688 ** sqlite3_unlock_notify() method with the blocked connection handle as | |
5689 ** the first argument to register for a callback that will be invoked | |
5690 ** when the blocking connections current transaction is concluded. ^The | |
5691 ** callback is invoked from within the [sqlite3_step] or [sqlite3_close] | |
5692 ** call that concludes the blocking connections transaction. | |
5693 ** | |
5694 ** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, | |
5695 ** there is a chance that the blocking connection will have already | |
5696 ** concluded its transaction by the time sqlite3_unlock_notify() is invoked. | |
5697 ** If this happens, then the specified callback is invoked immediately, | |
5698 ** from within the call to sqlite3_unlock_notify().)^ | |
5699 ** | |
5700 ** ^If the blocked connection is attempting to obtain a write-lock on a | |
5701 ** shared-cache table, and more than one other connection currently holds | |
5702 ** a read-lock on the same table, then SQLite arbitrarily selects one of | |
5703 ** the other connections to use as the blocking connection. | |
5704 ** | |
5705 ** ^(There may be at most one unlock-notify callback registered by a | |
5706 ** blocked connection. If sqlite3_unlock_notify() is called when the | |
5707 ** blocked connection already has a registered unlock-notify callback, | |
5708 ** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is | |
5709 ** called with a NULL pointer as its second argument, then any existing | |
5710 ** unlock-notify callback is cancelled. ^The blocked connections | |
5711 ** unlock-notify callback may also be canceled by closing the blocked | |
5712 ** connection using [sqlite3_close()]. | |
5713 ** | |
5714 ** The unlock-notify callback is not reentrant. If an application invokes | |
5715 ** any sqlite3_xxx API functions from within an unlock-notify callback, a | |
5716 ** crash or deadlock may be the result. | |
5717 ** | |
5718 ** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always | |
5719 ** returns SQLITE_OK. | |
5720 ** | |
5721 ** <b>Callback Invocation Details</b> | |
5722 ** | |
5723 ** When an unlock-notify callback is registered, the application provides a | |
5724 ** single void* pointer that is passed to the callback when it is invoked. | |
5725 ** However, the signature of the callback function allows SQLite to pass | |
5726 ** it an array of void* context pointers. The first argument passed to | |
5727 ** an unlock-notify callback is a pointer to an array of void* pointers, | |
5728 ** and the second is the number of entries in the array. | |
5729 ** | |
5730 ** When a blocking connections transaction is concluded, there may be | |
5731 ** more than one blocked connection that has registered for an unlock-notify | |
5732 ** callback. ^If two or more such blocked connections have specified the | |
5733 ** same callback function, then instead of invoking the callback function | |
5734 ** multiple times, it is invoked once with the set of void* context pointers | |
5735 ** specified by the blocked connections bundled together into an array. | |
5736 ** This gives the application an opportunity to prioritize any actions | |
5737 ** related to the set of unblocked database connections. | |
5738 ** | |
5739 ** <b>Deadlock Detection</b> | |
5740 ** | |
5741 ** Assuming that after registering for an unlock-notify callback a | |
5742 ** database waits for the callback to be issued before taking any further | |
5743 ** action (a reasonable assumption), then using this API may cause the | |
5744 ** application to deadlock. For example, if connection X is waiting for | |
5745 ** connection Y's transaction to be concluded, and similarly connection | |
5746 ** Y is waiting on connection X's transaction, then neither connection | |
5747 ** will proceed and the system may remain deadlocked indefinitely. | |
5748 ** | |
5749 ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock | |
5750 ** detection. ^If a given call to sqlite3_unlock_notify() would put the | |
5751 ** system in a deadlocked state, then SQLITE_LOCKED is returned and no | |
5752 ** unlock-notify callback is registered. The system is said to be in | |
5753 ** a deadlocked state if connection A has registered for an unlock-notify | |
5754 ** callback on the conclusion of connection B's transaction, and connection | |
5755 ** B has itself registered for an unlock-notify callback when connection | |
5756 ** A's transaction is concluded. ^Indirect deadlock is also detected, so | |
5757 ** the system is also considered to be deadlocked if connection B has | |
5758 ** registered for an unlock-notify callback on the conclusion of connection | |
5759 ** C's transaction, where connection C is waiting on connection A. ^Any | |
5760 ** number of levels of indirection are allowed. | |
5761 ** | |
5762 ** <b>The "DROP TABLE" Exception</b> | |
5763 ** | |
5764 ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost | |
5765 ** always appropriate to call sqlite3_unlock_notify(). There is however, | |
5766 ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, | |
5767 ** SQLite checks if there are any currently executing SELECT statements | |
5768 ** that belong to the same connection. If there are, SQLITE_LOCKED is | |
5769 ** returned. In this case there is no "blocking connection", so invoking | |
5770 ** sqlite3_unlock_notify() results in the unlock-notify callback being | |
5771 ** invoked immediately. If the application then re-attempts the "DROP TABLE" | |
5772 ** or "DROP INDEX" query, an infinite loop might be the result. | |
5773 ** | |
5774 ** One way around this problem is to check the extended error code returned | |
5775 ** by an sqlite3_step() call. ^(If there is a blocking connection, then the | |
5776 ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in | |
5777 ** the special "DROP TABLE/INDEX" case, the extended error code is just | |
5778 ** SQLITE_LOCKED.)^ | |
5779 */ | |
5780 SQLITE_API int sqlite3_unlock_notify( | |
5781 sqlite3 *pBlocked, /* Waiting connection */ | |
5782 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ | |
5783 void *pNotifyArg /* Argument to pass to xNotify */ | |
5784 ); | |
5785 | |
5786 | |
5787 /* | |
5788 ** CAPI3REF: String Comparison | |
5789 ** | |
5790 ** ^The [sqlite3_strnicmp()] API allows applications and extensions to | |
5791 ** compare the contents of two buffers containing UTF-8 strings in a | |
5792 ** case-indendent fashion, using the same definition of case independence | |
5793 ** that SQLite uses internally when comparing identifiers. | |
5794 */ | |
5795 SQLITE_API int sqlite3_strnicmp(const char *, const char *, int); | |
5796 | |
5797 /* | |
5798 ** CAPI3REF: Error Logging Interface | |
5799 ** | |
5800 ** ^The [sqlite3_log()] interface writes a message into the error log | |
5801 ** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. | |
5802 ** ^If logging is enabled, the zFormat string and subsequent arguments are | |
5803 ** used with [sqlite3_snprintf()] to generate the final output string. | |
5804 ** | |
5805 ** The sqlite3_log() interface is intended for use by extensions such as | |
5806 ** virtual tables, collating functions, and SQL functions. While there is | |
5807 ** nothing to prevent an application from calling sqlite3_log(), doing so | |
5808 ** is considered bad form. | |
5809 ** | |
5810 ** The zFormat string must not be NULL. | |
5811 ** | |
5812 ** To avoid deadlocks and other threading problems, the sqlite3_log() routine | |
5813 ** will not use dynamically allocated memory. The log message is stored in | |
5814 ** a fixed-length buffer on the stack. If the log message is longer than | |
5815 ** a few hundred characters, it will be truncated to the length of the | |
5816 ** buffer. | |
5817 */ | |
5818 SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...); | |
5819 | |
5820 /* | |
5821 ** CAPI3REF: Write-Ahead Log Commit Hook | |
5822 ** | |
5823 ** ^The [sqlite3_wal_hook()] function is used to register a callback that | |
5824 ** will be invoked each time a database connection commits data to a | |
5825 ** [write-ahead log] (i.e. whenever a transaction is committed in | |
5826 ** [journal_mode | journal_mode=WAL mode]). | |
5827 ** | |
5828 ** ^The callback is invoked by SQLite after the commit has taken place and | |
5829 ** the associated write-lock on the database released, so the implementation | |
5830 ** may read, write or [checkpoint] the database as required. | |
5831 ** | |
5832 ** ^The first parameter passed to the callback function when it is invoked | |
5833 ** is a copy of the third parameter passed to sqlite3_wal_hook() when | |
5834 ** registering the callback. ^The second is a copy of the database handle. | |
5835 ** ^The third parameter is the name of the database that was written to - | |
5836 ** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter | |
5837 ** is the number of pages currently in the write-ahead log file, | |
5838 ** including those that were just committed. | |
5839 ** | |
5840 ** The callback function should normally return [SQLITE_OK]. ^If an error | |
5841 ** code is returned, that error will propagate back up through the | |
5842 ** SQLite code base to cause the statement that provoked the callback | |
5843 ** to report an error, though the commit will have still occurred. If the | |
5844 ** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value | |
5845 ** that does not correspond to any valid SQLite error code, the results | |
5846 ** are undefined. | |
5847 ** | |
5848 ** A single database handle may have at most a single write-ahead log callback | |
5849 ** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any | |
5850 ** previously registered write-ahead log callback. ^Note that the | |
5851 ** [sqlite3_wal_autocheckpoint()] interface and the | |
5852 ** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will | |
5853 ** those overwrite any prior [sqlite3_wal_hook()] settings. | |
5854 */ | |
5855 SQLITE_API void *sqlite3_wal_hook( | |
5856 sqlite3*, | |
5857 int(*)(void *,sqlite3*,const char*,int), | |
5858 void* | |
5859 ); | |
5860 | |
5861 /* | |
5862 ** CAPI3REF: Configure an auto-checkpoint | |
5863 ** | |
5864 ** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around | |
5865 ** [sqlite3_wal_hook()] that causes any database on [database connection] D | |
5866 ** to automatically [checkpoint] | |
5867 ** after committing a transaction if there are N or | |
5868 ** more frames in the [write-ahead log] file. ^Passing zero or | |
5869 ** a negative value as the nFrame parameter disables automatic | |
5870 ** checkpoints entirely. | |
5871 ** | |
5872 ** ^The callback registered by this function replaces any existing callback | |
5873 ** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback | |
5874 ** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism | |
5875 ** configured by this function. | |
5876 ** | |
5877 ** ^The [wal_autocheckpoint pragma] can be used to invoke this interface | |
5878 ** from SQL. | |
5879 ** | |
5880 ** ^Every new [database connection] defaults to having the auto-checkpoint | |
5881 ** enabled with a threshold of 1000 pages. The use of this interface | |
5882 ** is only necessary if the default setting is found to be suboptimal | |
5883 ** for a particular application. | |
5884 */ | |
5885 SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); | |
5886 | |
5887 /* | |
5888 ** CAPI3REF: Checkpoint a database | |
5889 ** | |
5890 ** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X | |
5891 ** on [database connection] D to be [checkpointed]. ^If X is NULL or an | |
5892 ** empty string, then a checkpoint is run on all databases of | |
5893 ** connection D. ^If the database connection D is not in | |
5894 ** [WAL | write-ahead log mode] then this interface is a harmless no-op. | |
5895 ** | |
5896 ** ^The [wal_checkpoint pragma] can be used to invoke this interface | |
5897 ** from SQL. ^The [sqlite3_wal_autocheckpoint()] interface and the | |
5898 ** [wal_autocheckpoint pragma] can be used to cause this interface to be | |
5899 ** run whenever the WAL reaches a certain size threshold. | |
5900 */ | |
5901 SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); | |
5902 | |
5903 /* | |
5904 ** Undo the hack that converts floating point types to integer for | |
5905 ** builds on processors without floating point support. | |
5906 */ | |
5907 #ifdef SQLITE_OMIT_FLOATING_POINT | |
5908 # undef double | |
5909 #endif | |
5910 | |
5911 #ifdef __cplusplus | |
5912 } /* End of the 'extern "C"' block */ | |
5913 #endif | |
5914 #endif | |
5915 |