Annotation of embedaddon/php/ext/sqlite3/libsqlite/sqlite3.h, revision 1.1.1.1
1.1 misho 1: /*
2: ** 2001 September 15
3: **
4: ** The author disclaims copyright to this source code. In place of
5: ** a legal notice, here is a blessing:
6: **
7: ** May you do good and not evil.
8: ** May you find forgiveness for yourself and forgive others.
9: ** May you share freely, never taking more than you give.
10: **
11: *************************************************************************
12: ** This header file defines the interface that the SQLite library
13: ** presents to client programs. If a C-function, structure, datatype,
14: ** or constant definition does not appear in this file, then it is
15: ** not a published API of SQLite, is subject to change without
16: ** notice, and should not be referenced by programs that use SQLite.
17: **
18: ** Some of the definitions that are in this file are marked as
19: ** "experimental". Experimental interfaces are normally new
20: ** features recently added to SQLite. We do not anticipate changes
21: ** to experimental interfaces but reserve the right to make minor changes
22: ** if experience from use "in the wild" suggest such changes are prudent.
23: **
24: ** The official C-language API documentation for SQLite is derived
25: ** from comments in this file. This file is the authoritative source
26: ** on how SQLite interfaces are suppose to operate.
27: **
28: ** The name of this file under configuration management is "sqlite.h.in".
29: ** The makefile makes some minor changes to this file (such as inserting
30: ** the version number) and changes its name to "sqlite3.h" as
31: ** part of the build process.
32: */
33: #ifndef _SQLITE3_H_
34: #define _SQLITE3_H_
35: #include <stdarg.h> /* Needed for the definition of va_list */
36:
37: /*
38: ** Make sure we can call this stuff from C++.
39: */
40: #ifdef __cplusplus
41: extern "C" {
42: #endif
43:
44:
45: /*
46: ** Add the ability to override 'extern'
47: */
48: #ifndef SQLITE_EXTERN
49: # define SQLITE_EXTERN extern
50: #endif
51:
52: #ifndef SQLITE_API
53: # define SQLITE_API
54: #endif
55:
56:
57: /*
58: ** These no-op macros are used in front of interfaces to mark those
59: ** interfaces as either deprecated or experimental. New applications
60: ** should not use deprecated interfaces - they are support for backwards
61: ** compatibility only. Application writers should be aware that
62: ** experimental interfaces are subject to change in point releases.
63: **
64: ** These macros used to resolve to various kinds of compiler magic that
65: ** would generate warning messages when they were used. But that
66: ** compiler magic ended up generating such a flurry of bug reports
67: ** that we have taken it all out and gone back to using simple
68: ** noop macros.
69: */
70: #define SQLITE_DEPRECATED
71: #define SQLITE_EXPERIMENTAL
72:
73: /*
74: ** Ensure these symbols were not defined by some previous header file.
75: */
76: #ifdef SQLITE_VERSION
77: # undef SQLITE_VERSION
78: #endif
79: #ifdef SQLITE_VERSION_NUMBER
80: # undef SQLITE_VERSION_NUMBER
81: #endif
82:
83: /*
84: ** CAPI3REF: Compile-Time Library Version Numbers
85: **
86: ** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header
87: ** evaluates to a string literal that is the SQLite version in the
88: ** format "X.Y.Z" where X is the major version number (always 3 for
89: ** SQLite3) and Y is the minor version number and Z is the release number.)^
90: ** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer
91: ** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same
92: ** numbers used in [SQLITE_VERSION].)^
93: ** The SQLITE_VERSION_NUMBER for any given release of SQLite will also
94: ** be larger than the release from which it is derived. Either Y will
95: ** be held constant and Z will be incremented or else Y will be incremented
96: ** and Z will be reset to zero.
97: **
98: ** Since version 3.6.18, SQLite source code has been stored in the
99: ** <a href="http://www.fossil-scm.org/">Fossil configuration management
100: ** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to
101: ** a string which identifies a particular check-in of SQLite
102: ** within its configuration management system. ^The SQLITE_SOURCE_ID
103: ** string contains the date and time of the check-in (UTC) and an SHA1
104: ** hash of the entire source tree.
105: **
106: ** See also: [sqlite3_libversion()],
107: ** [sqlite3_libversion_number()], [sqlite3_sourceid()],
108: ** [sqlite_version()] and [sqlite_source_id()].
109: */
110: #define SQLITE_VERSION "3.7.7.1"
111: #define SQLITE_VERSION_NUMBER 3007007
112: #define SQLITE_SOURCE_ID "2011-06-28 17:39:05 af0d91adf497f5f36ec3813f04235a6e195a605f"
113:
114: /*
115: ** CAPI3REF: Run-Time Library Version Numbers
116: ** KEYWORDS: sqlite3_version, sqlite3_sourceid
117: **
118: ** These interfaces provide the same information as the [SQLITE_VERSION],
119: ** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros
120: ** but are associated with the library instead of the header file. ^(Cautious
121: ** programmers might include assert() statements in their application to
122: ** verify that values returned by these interfaces match the macros in
123: ** the header, and thus insure that the application is
124: ** compiled with matching library and header files.
125: **
126: ** <blockquote><pre>
127: ** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
128: ** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 );
129: ** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
130: ** </pre></blockquote>)^
131: **
132: ** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION]
133: ** macro. ^The sqlite3_libversion() function returns a pointer to the
134: ** to the sqlite3_version[] string constant. The sqlite3_libversion()
135: ** function is provided for use in DLLs since DLL users usually do not have
136: ** direct access to string constants within the DLL. ^The
137: ** sqlite3_libversion_number() function returns an integer equal to
138: ** [SQLITE_VERSION_NUMBER]. ^The sqlite3_sourceid() function returns
139: ** a pointer to a string constant whose value is the same as the
140: ** [SQLITE_SOURCE_ID] C preprocessor macro.
141: **
142: ** See also: [sqlite_version()] and [sqlite_source_id()].
143: */
144: SQLITE_API SQLITE_EXTERN const char sqlite3_version[];
145: SQLITE_API const char *sqlite3_libversion(void);
146: SQLITE_API const char *sqlite3_sourceid(void);
147: SQLITE_API int sqlite3_libversion_number(void);
148:
149: /*
150: ** CAPI3REF: Run-Time Library Compilation Options Diagnostics
151: **
152: ** ^The sqlite3_compileoption_used() function returns 0 or 1
153: ** indicating whether the specified option was defined at
154: ** compile time. ^The SQLITE_ prefix may be omitted from the
155: ** option name passed to sqlite3_compileoption_used().
156: **
157: ** ^The sqlite3_compileoption_get() function allows iterating
158: ** over the list of options that were defined at compile time by
159: ** returning the N-th compile time option string. ^If N is out of range,
160: ** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_
161: ** prefix is omitted from any strings returned by
162: ** sqlite3_compileoption_get().
163: **
164: ** ^Support for the diagnostic functions sqlite3_compileoption_used()
165: ** and sqlite3_compileoption_get() may be omitted by specifying the
166: ** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time.
167: **
168: ** See also: SQL functions [sqlite_compileoption_used()] and
169: ** [sqlite_compileoption_get()] and the [compile_options pragma].
170: */
171: #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
172: SQLITE_API int sqlite3_compileoption_used(const char *zOptName);
173: SQLITE_API const char *sqlite3_compileoption_get(int N);
174: #endif
175:
176: /*
177: ** CAPI3REF: Test To See If The Library Is Threadsafe
178: **
179: ** ^The sqlite3_threadsafe() function returns zero if and only if
180: ** SQLite was compiled 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: ** successfully destroyed and all associated resources are deallocated.
272: **
273: ** Applications must [sqlite3_finalize | finalize] all [prepared statements]
274: ** and [sqlite3_blob_close | close] all [BLOB handles] associated with
275: ** the [sqlite3] object prior to attempting to close the object. ^If
276: ** sqlite3_close() is called on a [database connection] that still has
277: ** outstanding [prepared statements] or [BLOB handles], then it returns
278: ** SQLITE_BUSY.
279: **
280: ** ^If [sqlite3_close()] is invoked while a transaction is open,
281: ** the transaction is automatically rolled back.
282: **
283: ** The C parameter to [sqlite3_close(C)] must be either a NULL
284: ** pointer or an [sqlite3] object pointer obtained
285: ** from [sqlite3_open()], [sqlite3_open16()], or
286: ** [sqlite3_open_v2()], and not previously closed.
287: ** ^Calling sqlite3_close() with a NULL pointer argument is a
288: ** harmless no-op.
289: */
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: ** 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: ** [sqlite3_vtab_on_conflict()] [SQLITE_ROLLBACK | result codes].
380: */
381: #define SQLITE_OK 0 /* Successful result */
382: /* beginning-of-error-codes */
383: #define SQLITE_ERROR 1 /* SQL error or missing database */
384: #define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */
385: #define SQLITE_PERM 3 /* Access permission denied */
386: #define SQLITE_ABORT 4 /* Callback routine requested an abort */
387: #define SQLITE_BUSY 5 /* The database file is locked */
388: #define SQLITE_LOCKED 6 /* A table in the database is locked */
389: #define SQLITE_NOMEM 7 /* A malloc() failed */
390: #define SQLITE_READONLY 8 /* Attempt to write a readonly database */
391: #define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/
392: #define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */
393: #define SQLITE_CORRUPT 11 /* The database disk image is malformed */
394: #define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */
395: #define SQLITE_FULL 13 /* Insertion failed because database is full */
396: #define SQLITE_CANTOPEN 14 /* Unable to open the database file */
397: #define SQLITE_PROTOCOL 15 /* Database lock protocol error */
398: #define SQLITE_EMPTY 16 /* Database is empty */
399: #define SQLITE_SCHEMA 17 /* The database schema changed */
400: #define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */
401: #define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */
402: #define SQLITE_MISMATCH 20 /* Data type mismatch */
403: #define SQLITE_MISUSE 21 /* Library used incorrectly */
404: #define SQLITE_NOLFS 22 /* Uses OS features not supported on host */
405: #define SQLITE_AUTH 23 /* Authorization denied */
406: #define SQLITE_FORMAT 24 /* Auxiliary database format error */
407: #define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */
408: #define SQLITE_NOTADB 26 /* File opened that is not a database file */
409: #define SQLITE_ROW 100 /* sqlite3_step() has another row ready */
410: #define SQLITE_DONE 101 /* sqlite3_step() has finished executing */
411: /* end-of-error-codes */
412:
413: /*
414: ** CAPI3REF: Extended Result Codes
415: ** KEYWORDS: {extended error code} {extended error codes}
416: ** KEYWORDS: {extended result code} {extended result codes}
417: **
418: ** In its default configuration, SQLite API routines return one of 26 integer
419: ** [SQLITE_OK | result codes]. However, experience has shown that many of
420: ** these result codes are too coarse-grained. They do not provide as
421: ** much information about problems as programmers might like. In an effort to
422: ** address this, newer versions of SQLite (version 3.3.8 and later) include
423: ** support for additional result codes that provide more detailed information
424: ** about errors. The extended result codes are enabled or disabled
425: ** on a per database connection basis using the
426: ** [sqlite3_extended_result_codes()] API.
427: **
428: ** Some of the available extended result codes are listed here.
429: ** One may expect the number of extended result codes will be expand
430: ** over time. Software that uses extended result codes should expect
431: ** to see new result codes in future releases of SQLite.
432: **
433: ** The SQLITE_OK result code will never be extended. It will always
434: ** be exactly zero.
435: */
436: #define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8))
437: #define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8))
438: #define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8))
439: #define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8))
440: #define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8))
441: #define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8))
442: #define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8))
443: #define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8))
444: #define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8))
445: #define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8))
446: #define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8))
447: #define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8))
448: #define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8))
449: #define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
450: #define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8))
451: #define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8))
452: #define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8))
453: #define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8))
454: #define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8))
455: #define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8))
456: #define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8))
457: #define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8))
458: #define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8))
459: #define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8))
460: #define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8))
461: #define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8))
462: #define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8))
463: #define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8))
464:
465: /*
466: ** CAPI3REF: Flags For File Open Operations
467: **
468: ** These bit values are intended for use in the
469: ** 3rd parameter to the [sqlite3_open_v2()] interface and
470: ** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
471: */
472: #define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */
473: #define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */
474: #define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */
475: #define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */
476: #define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */
477: #define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */
478: #define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */
479: #define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */
480: #define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */
481: #define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */
482: #define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */
483: #define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */
484: #define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */
485: #define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */
486: #define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */
487: #define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */
488: #define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */
489: #define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */
490: #define SQLITE_OPEN_WAL 0x00080000 /* VFS only */
491:
492: /* Reserved: 0x00F00000 */
493:
494: /*
495: ** CAPI3REF: Device Characteristics
496: **
497: ** The xDeviceCharacteristics method of the [sqlite3_io_methods]
498: ** object returns an integer which is a vector of the these
499: ** bit values expressing I/O characteristics of the mass storage
500: ** device that holds the file that the [sqlite3_io_methods]
501: ** refers to.
502: **
503: ** The SQLITE_IOCAP_ATOMIC property means that all writes of
504: ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
505: ** mean that writes of blocks that are nnn bytes in size and
506: ** are aligned to an address which is an integer multiple of
507: ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
508: ** that when data is appended to a file, the data is appended
509: ** first then the size of the file is extended, never the other
510: ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
511: ** information is written to disk in the same order as calls
512: ** to xWrite().
513: */
514: #define SQLITE_IOCAP_ATOMIC 0x00000001
515: #define SQLITE_IOCAP_ATOMIC512 0x00000002
516: #define SQLITE_IOCAP_ATOMIC1K 0x00000004
517: #define SQLITE_IOCAP_ATOMIC2K 0x00000008
518: #define SQLITE_IOCAP_ATOMIC4K 0x00000010
519: #define SQLITE_IOCAP_ATOMIC8K 0x00000020
520: #define SQLITE_IOCAP_ATOMIC16K 0x00000040
521: #define SQLITE_IOCAP_ATOMIC32K 0x00000080
522: #define SQLITE_IOCAP_ATOMIC64K 0x00000100
523: #define SQLITE_IOCAP_SAFE_APPEND 0x00000200
524: #define SQLITE_IOCAP_SEQUENTIAL 0x00000400
525: #define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800
526:
527: /*
528: ** CAPI3REF: File Locking Levels
529: **
530: ** SQLite uses one of these integer values as the second
531: ** argument to calls it makes to the xLock() and xUnlock() methods
532: ** of an [sqlite3_io_methods] object.
533: */
534: #define SQLITE_LOCK_NONE 0
535: #define SQLITE_LOCK_SHARED 1
536: #define SQLITE_LOCK_RESERVED 2
537: #define SQLITE_LOCK_PENDING 3
538: #define SQLITE_LOCK_EXCLUSIVE 4
539:
540: /*
541: ** CAPI3REF: Synchronization Type Flags
542: **
543: ** When SQLite invokes the xSync() method of an
544: ** [sqlite3_io_methods] object it uses a combination of
545: ** these integer values as the second argument.
546: **
547: ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
548: ** sync operation only needs to flush data to mass storage. Inode
549: ** information need not be flushed. If the lower four bits of the flag
550: ** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
551: ** If the lower four bits equal SQLITE_SYNC_FULL, that means
552: ** to use Mac OS X style fullsync instead of fsync().
553: **
554: ** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
555: ** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
556: ** settings. The [synchronous pragma] determines when calls to the
557: ** xSync VFS method occur and applies uniformly across all platforms.
558: ** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
559: ** energetic or rigorous or forceful the sync operations are and
560: ** only make a difference on Mac OSX for the default SQLite code.
561: ** (Third-party VFS implementations might also make the distinction
562: ** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
563: ** operating systems natively supported by SQLite, only Mac OSX
564: ** cares about the difference.)
565: */
566: #define SQLITE_SYNC_NORMAL 0x00002
567: #define SQLITE_SYNC_FULL 0x00003
568: #define SQLITE_SYNC_DATAONLY 0x00010
569:
570: /*
571: ** CAPI3REF: OS Interface Open File Handle
572: **
573: ** An [sqlite3_file] object represents an open file in the
574: ** [sqlite3_vfs | OS interface layer]. Individual OS interface
575: ** implementations will
576: ** want to subclass this object by appending additional fields
577: ** for their own use. The pMethods entry is a pointer to an
578: ** [sqlite3_io_methods] object that defines methods for performing
579: ** I/O operations on the open file.
580: */
581: typedef struct sqlite3_file sqlite3_file;
582: struct sqlite3_file {
583: const struct sqlite3_io_methods *pMethods; /* Methods for an open file */
584: };
585:
586: /*
587: ** CAPI3REF: OS Interface File Virtual Methods Object
588: **
589: ** Every file opened by the [sqlite3_vfs.xOpen] method populates an
590: ** [sqlite3_file] object (or, more commonly, a subclass of the
591: ** [sqlite3_file] object) with a pointer to an instance of this object.
592: ** This object defines the methods used to perform various operations
593: ** against the open file represented by the [sqlite3_file] object.
594: **
595: ** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element
596: ** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
597: ** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The
598: ** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
599: ** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
600: ** to NULL.
601: **
602: ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
603: ** [SQLITE_SYNC_FULL]. The first choice is the normal fsync().
604: ** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY]
605: ** flag may be ORed in to indicate that only the data of the file
606: ** and not its inode needs to be synced.
607: **
608: ** The integer values to xLock() and xUnlock() are one of
609: ** <ul>
610: ** <li> [SQLITE_LOCK_NONE],
611: ** <li> [SQLITE_LOCK_SHARED],
612: ** <li> [SQLITE_LOCK_RESERVED],
613: ** <li> [SQLITE_LOCK_PENDING], or
614: ** <li> [SQLITE_LOCK_EXCLUSIVE].
615: ** </ul>
616: ** xLock() increases the lock. xUnlock() decreases the lock.
617: ** The xCheckReservedLock() method checks whether any database connection,
618: ** either in this process or in some other process, is holding a RESERVED,
619: ** PENDING, or EXCLUSIVE lock on the file. It returns true
620: ** if such a lock exists and false otherwise.
621: **
622: ** The xFileControl() method is a generic interface that allows custom
623: ** VFS implementations to directly control an open file using the
624: ** [sqlite3_file_control()] interface. The second "op" argument is an
625: ** integer opcode. The third argument is a generic pointer intended to
626: ** point to a structure that may contain arguments or space in which to
627: ** write return values. Potential uses for xFileControl() might be
628: ** functions to enable blocking locks with timeouts, to change the
629: ** locking strategy (for example to use dot-file locks), to inquire
630: ** about the status of a lock, or to break stale locks. The SQLite
631: ** core reserves all opcodes less than 100 for its own use.
632: ** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available.
633: ** Applications that define a custom xFileControl method should use opcodes
634: ** greater than 100 to avoid conflicts. VFS implementations should
635: ** return [SQLITE_NOTFOUND] for file control opcodes that they do not
636: ** recognize.
637: **
638: ** The xSectorSize() method returns the sector size of the
639: ** device that underlies the file. The sector size is the
640: ** minimum write that can be performed without disturbing
641: ** other bytes in the file. The xDeviceCharacteristics()
642: ** method returns a bit vector describing behaviors of the
643: ** underlying device:
644: **
645: ** <ul>
646: ** <li> [SQLITE_IOCAP_ATOMIC]
647: ** <li> [SQLITE_IOCAP_ATOMIC512]
648: ** <li> [SQLITE_IOCAP_ATOMIC1K]
649: ** <li> [SQLITE_IOCAP_ATOMIC2K]
650: ** <li> [SQLITE_IOCAP_ATOMIC4K]
651: ** <li> [SQLITE_IOCAP_ATOMIC8K]
652: ** <li> [SQLITE_IOCAP_ATOMIC16K]
653: ** <li> [SQLITE_IOCAP_ATOMIC32K]
654: ** <li> [SQLITE_IOCAP_ATOMIC64K]
655: ** <li> [SQLITE_IOCAP_SAFE_APPEND]
656: ** <li> [SQLITE_IOCAP_SEQUENTIAL]
657: ** </ul>
658: **
659: ** The SQLITE_IOCAP_ATOMIC property means that all writes of
660: ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
661: ** mean that writes of blocks that are nnn bytes in size and
662: ** are aligned to an address which is an integer multiple of
663: ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
664: ** that when data is appended to a file, the data is appended
665: ** first then the size of the file is extended, never the other
666: ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
667: ** information is written to disk in the same order as calls
668: ** to xWrite().
669: **
670: ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
671: ** in the unread portions of the buffer with zeros. A VFS that
672: ** fails to zero-fill short reads might seem to work. However,
673: ** failure to zero-fill short reads will eventually lead to
674: ** database corruption.
675: */
676: typedef struct sqlite3_io_methods sqlite3_io_methods;
677: struct sqlite3_io_methods {
678: int iVersion;
679: int (*xClose)(sqlite3_file*);
680: int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
681: int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
682: int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
683: int (*xSync)(sqlite3_file*, int flags);
684: int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
685: int (*xLock)(sqlite3_file*, int);
686: int (*xUnlock)(sqlite3_file*, int);
687: int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
688: int (*xFileControl)(sqlite3_file*, int op, void *pArg);
689: int (*xSectorSize)(sqlite3_file*);
690: int (*xDeviceCharacteristics)(sqlite3_file*);
691: /* Methods above are valid for version 1 */
692: int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
693: int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
694: void (*xShmBarrier)(sqlite3_file*);
695: int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
696: /* Methods above are valid for version 2 */
697: /* Additional methods may be added in future releases */
698: };
699:
700: /*
701: ** CAPI3REF: Standard File Control Opcodes
702: **
703: ** These integer constants are opcodes for the xFileControl method
704: ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
705: ** interface.
706: **
707: ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This
708: ** opcode causes the xFileControl method to write the current state of
709: ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
710: ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
711: ** into an integer that the pArg argument points to. This capability
712: ** is used during testing and only needs to be supported when SQLITE_TEST
713: ** is defined.
714: **
715: ** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
716: ** layer a hint of how large the database file will grow to be during the
717: ** current transaction. This hint is not guaranteed to be accurate but it
718: ** is often close. The underlying VFS might choose to preallocate database
719: ** file space based on this hint in order to help writes to the database
720: ** file run faster.
721: **
722: ** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
723: ** extends and truncates the database file in chunks of a size specified
724: ** by the user. The fourth argument to [sqlite3_file_control()] should
725: ** point to an integer (type int) containing the new chunk-size to use
726: ** for the nominated database. Allocating database file space in large
727: ** chunks (say 1MB at a time), may reduce file-system fragmentation and
728: ** improve performance on some systems.
729: **
730: ** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
731: ** to the [sqlite3_file] object associated with a particular database
732: ** connection. See the [sqlite3_file_control()] documentation for
733: ** additional information.
734: **
735: ** ^(The [SQLITE_FCNTL_SYNC_OMITTED] opcode is generated internally by
736: ** SQLite and sent to all VFSes in place of a call to the xSync method
737: ** when the database connection has [PRAGMA synchronous] set to OFF.)^
738: ** Some specialized VFSes need this signal in order to operate correctly
739: ** when [PRAGMA synchronous | PRAGMA synchronous=OFF] is set, but most
740: ** VFSes do not need this signal and should silently ignore this opcode.
741: ** Applications should not call [sqlite3_file_control()] with this
742: ** opcode as doing so may disrupt the operation of the specialized VFSes
743: ** that do require it.
744: */
745: #define SQLITE_FCNTL_LOCKSTATE 1
746: #define SQLITE_GET_LOCKPROXYFILE 2
747: #define SQLITE_SET_LOCKPROXYFILE 3
748: #define SQLITE_LAST_ERRNO 4
749: #define SQLITE_FCNTL_SIZE_HINT 5
750: #define SQLITE_FCNTL_CHUNK_SIZE 6
751: #define SQLITE_FCNTL_FILE_POINTER 7
752: #define SQLITE_FCNTL_SYNC_OMITTED 8
753:
754:
755: /*
756: ** CAPI3REF: Mutex Handle
757: **
758: ** The mutex module within SQLite defines [sqlite3_mutex] to be an
759: ** abstract type for a mutex object. The SQLite core never looks
760: ** at the internal representation of an [sqlite3_mutex]. It only
761: ** deals with pointers to the [sqlite3_mutex] object.
762: **
763: ** Mutexes are created using [sqlite3_mutex_alloc()].
764: */
765: typedef struct sqlite3_mutex sqlite3_mutex;
766:
767: /*
768: ** CAPI3REF: OS Interface Object
769: **
770: ** An instance of the sqlite3_vfs object defines the interface between
771: ** the SQLite core and the underlying operating system. The "vfs"
772: ** in the name of the object stands for "virtual file system". See
773: ** the [VFS | VFS documentation] for further information.
774: **
775: ** The value of the iVersion field is initially 1 but may be larger in
776: ** future versions of SQLite. Additional fields may be appended to this
777: ** object when the iVersion value is increased. Note that the structure
778: ** of the sqlite3_vfs object changes in the transaction between
779: ** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not
780: ** modified.
781: **
782: ** The szOsFile field is the size of the subclassed [sqlite3_file]
783: ** structure used by this VFS. mxPathname is the maximum length of
784: ** a pathname in this VFS.
785: **
786: ** Registered sqlite3_vfs objects are kept on a linked list formed by
787: ** the pNext pointer. The [sqlite3_vfs_register()]
788: ** and [sqlite3_vfs_unregister()] interfaces manage this list
789: ** in a thread-safe way. The [sqlite3_vfs_find()] interface
790: ** searches the list. Neither the application code nor the VFS
791: ** implementation should use the pNext pointer.
792: **
793: ** The pNext field is the only field in the sqlite3_vfs
794: ** structure that SQLite will ever modify. SQLite will only access
795: ** or modify this field while holding a particular static mutex.
796: ** The application should never modify anything within the sqlite3_vfs
797: ** object once the object has been registered.
798: **
799: ** The zName field holds the name of the VFS module. The name must
800: ** be unique across all VFS modules.
801: **
802: ** [[sqlite3_vfs.xOpen]]
803: ** ^SQLite guarantees that the zFilename parameter to xOpen
804: ** is either a NULL pointer or string obtained
805: ** from xFullPathname() with an optional suffix added.
806: ** ^If a suffix is added to the zFilename parameter, it will
807: ** consist of a single "-" character followed by no more than
808: ** 10 alphanumeric and/or "-" characters.
809: ** ^SQLite further guarantees that
810: ** the string will be valid and unchanged until xClose() is
811: ** called. Because of the previous sentence,
812: ** the [sqlite3_file] can safely store a pointer to the
813: ** filename if it needs to remember the filename for some reason.
814: ** If the zFilename parameter to xOpen is a NULL pointer then xOpen
815: ** must invent its own temporary name for the file. ^Whenever the
816: ** xFilename parameter is NULL it will also be the case that the
817: ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
818: **
819: ** The flags argument to xOpen() includes all bits set in
820: ** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()]
821: ** or [sqlite3_open16()] is used, then flags includes at least
822: ** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE].
823: ** If xOpen() opens a file read-only then it sets *pOutFlags to
824: ** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set.
825: **
826: ** ^(SQLite will also add one of the following flags to the xOpen()
827: ** call, depending on the object being opened:
828: **
829: ** <ul>
830: ** <li> [SQLITE_OPEN_MAIN_DB]
831: ** <li> [SQLITE_OPEN_MAIN_JOURNAL]
832: ** <li> [SQLITE_OPEN_TEMP_DB]
833: ** <li> [SQLITE_OPEN_TEMP_JOURNAL]
834: ** <li> [SQLITE_OPEN_TRANSIENT_DB]
835: ** <li> [SQLITE_OPEN_SUBJOURNAL]
836: ** <li> [SQLITE_OPEN_MASTER_JOURNAL]
837: ** <li> [SQLITE_OPEN_WAL]
838: ** </ul>)^
839: **
840: ** The file I/O implementation can use the object type flags to
841: ** change the way it deals with files. For example, an application
842: ** that does not care about crash recovery or rollback might make
843: ** the open of a journal file a no-op. Writes to this journal would
844: ** also be no-ops, and any attempt to read the journal would return
845: ** SQLITE_IOERR. Or the implementation might recognize that a database
846: ** file will be doing page-aligned sector reads and writes in a random
847: ** order and set up its I/O subsystem accordingly.
848: **
849: ** SQLite might also add one of the following flags to the xOpen method:
850: **
851: ** <ul>
852: ** <li> [SQLITE_OPEN_DELETEONCLOSE]
853: ** <li> [SQLITE_OPEN_EXCLUSIVE]
854: ** </ul>
855: **
856: ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
857: ** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE]
858: ** will be set for TEMP databases and their journals, transient
859: ** databases, and subjournals.
860: **
861: ** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
862: ** with the [SQLITE_OPEN_CREATE] flag, which are both directly
863: ** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
864: ** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
865: ** SQLITE_OPEN_CREATE, is used to indicate that file should always
866: ** be created, and that it is an error if it already exists.
867: ** It is <i>not</i> used to indicate the file should be opened
868: ** for exclusive access.
869: **
870: ** ^At least szOsFile bytes of memory are allocated by SQLite
871: ** to hold the [sqlite3_file] structure passed as the third
872: ** argument to xOpen. The xOpen method does not have to
873: ** allocate the structure; it should just fill it in. Note that
874: ** the xOpen method must set the sqlite3_file.pMethods to either
875: ** a valid [sqlite3_io_methods] object or to NULL. xOpen must do
876: ** this even if the open fails. SQLite expects that the sqlite3_file.pMethods
877: ** element will be valid after xOpen returns regardless of the success
878: ** or failure of the xOpen call.
879: **
880: ** [[sqlite3_vfs.xAccess]]
881: ** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
882: ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
883: ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
884: ** to test whether a file is at least readable. The file can be a
885: ** directory.
886: **
887: ** ^SQLite will always allocate at least mxPathname+1 bytes for the
888: ** output buffer xFullPathname. The exact size of the output buffer
889: ** is also passed as a parameter to both methods. If the output buffer
890: ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
891: ** handled as a fatal error by SQLite, vfs implementations should endeavor
892: ** to prevent this by setting mxPathname to a sufficiently large value.
893: **
894: ** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
895: ** interfaces are not strictly a part of the filesystem, but they are
896: ** included in the VFS structure for completeness.
897: ** The xRandomness() function attempts to return nBytes bytes
898: ** of good-quality randomness into zOut. The return value is
899: ** the actual number of bytes of randomness obtained.
900: ** The xSleep() method causes the calling thread to sleep for at
901: ** least the number of microseconds given. ^The xCurrentTime()
902: ** method returns a Julian Day Number for the current date and time as
903: ** a floating point value.
904: ** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
905: ** Day Number multiplied by 86400000 (the number of milliseconds in
906: ** a 24-hour day).
907: ** ^SQLite will use the xCurrentTimeInt64() method to get the current
908: ** date and time if that method is available (if iVersion is 2 or
909: ** greater and the function pointer is not NULL) and will fall back
910: ** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
911: **
912: ** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
913: ** are not used by the SQLite core. These optional interfaces are provided
914: ** by some VFSes to facilitate testing of the VFS code. By overriding
915: ** system calls with functions under its control, a test program can
916: ** simulate faults and error conditions that would otherwise be difficult
917: ** or impossible to induce. The set of system calls that can be overridden
918: ** varies from one VFS to another, and from one version of the same VFS to the
919: ** next. Applications that use these interfaces must be prepared for any
920: ** or all of these interfaces to be NULL or for their behavior to change
921: ** from one release to the next. Applications must not attempt to access
922: ** any of these methods if the iVersion of the VFS is less than 3.
923: */
924: typedef struct sqlite3_vfs sqlite3_vfs;
925: typedef void (*sqlite3_syscall_ptr)(void);
926: struct sqlite3_vfs {
927: int iVersion; /* Structure version number (currently 3) */
928: int szOsFile; /* Size of subclassed sqlite3_file */
929: int mxPathname; /* Maximum file pathname length */
930: sqlite3_vfs *pNext; /* Next registered VFS */
931: const char *zName; /* Name of this virtual file system */
932: void *pAppData; /* Pointer to application-specific data */
933: int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
934: int flags, int *pOutFlags);
935: int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
936: int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
937: int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
938: void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
939: void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
940: void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
941: void (*xDlClose)(sqlite3_vfs*, void*);
942: int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
943: int (*xSleep)(sqlite3_vfs*, int microseconds);
944: int (*xCurrentTime)(sqlite3_vfs*, double*);
945: int (*xGetLastError)(sqlite3_vfs*, int, char *);
946: /*
947: ** The methods above are in version 1 of the sqlite_vfs object
948: ** definition. Those that follow are added in version 2 or later
949: */
950: int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
951: /*
952: ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
953: ** Those below are for version 3 and greater.
954: */
955: int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
956: sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
957: const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
958: /*
959: ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
960: ** New fields may be appended in figure versions. The iVersion
961: ** value will increment whenever this happens.
962: */
963: };
964:
965: /*
966: ** CAPI3REF: Flags for the xAccess VFS method
967: **
968: ** These integer constants can be used as the third parameter to
969: ** the xAccess method of an [sqlite3_vfs] object. They determine
970: ** what kind of permissions the xAccess method is looking for.
971: ** With SQLITE_ACCESS_EXISTS, the xAccess method
972: ** simply checks whether the file exists.
973: ** With SQLITE_ACCESS_READWRITE, the xAccess method
974: ** checks whether the named directory is both readable and writable
975: ** (in other words, if files can be added, removed, and renamed within
976: ** the directory).
977: ** The SQLITE_ACCESS_READWRITE constant is currently used only by the
978: ** [temp_store_directory pragma], though this could change in a future
979: ** release of SQLite.
980: ** With SQLITE_ACCESS_READ, the xAccess method
981: ** checks whether the file is readable. The SQLITE_ACCESS_READ constant is
982: ** currently unused, though it might be used in a future release of
983: ** SQLite.
984: */
985: #define SQLITE_ACCESS_EXISTS 0
986: #define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */
987: #define SQLITE_ACCESS_READ 2 /* Unused */
988:
989: /*
990: ** CAPI3REF: Flags for the xShmLock VFS method
991: **
992: ** These integer constants define the various locking operations
993: ** allowed by the xShmLock method of [sqlite3_io_methods]. The
994: ** following are the only legal combinations of flags to the
995: ** xShmLock method:
996: **
997: ** <ul>
998: ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
999: ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
1000: ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
1001: ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
1002: ** </ul>
1003: **
1004: ** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
1005: ** was given no the corresponding lock.
1006: **
1007: ** The xShmLock method can transition between unlocked and SHARED or
1008: ** between unlocked and EXCLUSIVE. It cannot transition between SHARED
1009: ** and EXCLUSIVE.
1010: */
1011: #define SQLITE_SHM_UNLOCK 1
1012: #define SQLITE_SHM_LOCK 2
1013: #define SQLITE_SHM_SHARED 4
1014: #define SQLITE_SHM_EXCLUSIVE 8
1015:
1016: /*
1017: ** CAPI3REF: Maximum xShmLock index
1018: **
1019: ** The xShmLock method on [sqlite3_io_methods] may use values
1020: ** between 0 and this upper bound as its "offset" argument.
1021: ** The SQLite core will never attempt to acquire or release a
1022: ** lock outside of this range
1023: */
1024: #define SQLITE_SHM_NLOCK 8
1025:
1026:
1027: /*
1028: ** CAPI3REF: Initialize The SQLite Library
1029: **
1030: ** ^The sqlite3_initialize() routine initializes the
1031: ** SQLite library. ^The sqlite3_shutdown() routine
1032: ** deallocates any resources that were allocated by sqlite3_initialize().
1033: ** These routines are designed to aid in process initialization and
1034: ** shutdown on embedded systems. Workstation applications using
1035: ** SQLite normally do not need to invoke either of these routines.
1036: **
1037: ** A call to sqlite3_initialize() is an "effective" call if it is
1038: ** the first time sqlite3_initialize() is invoked during the lifetime of
1039: ** the process, or if it is the first time sqlite3_initialize() is invoked
1040: ** following a call to sqlite3_shutdown(). ^(Only an effective call
1041: ** of sqlite3_initialize() does any initialization. All other calls
1042: ** are harmless no-ops.)^
1043: **
1044: ** A call to sqlite3_shutdown() is an "effective" call if it is the first
1045: ** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only
1046: ** an effective call to sqlite3_shutdown() does any deinitialization.
1047: ** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
1048: **
1049: ** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
1050: ** is not. The sqlite3_shutdown() interface must only be called from a
1051: ** single thread. All open [database connections] must be closed and all
1052: ** other SQLite resources must be deallocated prior to invoking
1053: ** sqlite3_shutdown().
1054: **
1055: ** Among other things, ^sqlite3_initialize() will invoke
1056: ** sqlite3_os_init(). Similarly, ^sqlite3_shutdown()
1057: ** will invoke sqlite3_os_end().
1058: **
1059: ** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
1060: ** ^If for some reason, sqlite3_initialize() is unable to initialize
1061: ** the library (perhaps it is unable to allocate a needed resource such
1062: ** as a mutex) it returns an [error code] other than [SQLITE_OK].
1063: **
1064: ** ^The sqlite3_initialize() routine is called internally by many other
1065: ** SQLite interfaces so that an application usually does not need to
1066: ** invoke sqlite3_initialize() directly. For example, [sqlite3_open()]
1067: ** calls sqlite3_initialize() so the SQLite library will be automatically
1068: ** initialized when [sqlite3_open()] is called if it has not be initialized
1069: ** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
1070: ** compile-time option, then the automatic calls to sqlite3_initialize()
1071: ** are omitted and the application must call sqlite3_initialize() directly
1072: ** prior to using any other SQLite interface. For maximum portability,
1073: ** it is recommended that applications always invoke sqlite3_initialize()
1074: ** directly prior to using any other SQLite interface. Future releases
1075: ** of SQLite may require this. In other words, the behavior exhibited
1076: ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
1077: ** default behavior in some future release of SQLite.
1078: **
1079: ** The sqlite3_os_init() routine does operating-system specific
1080: ** initialization of the SQLite library. The sqlite3_os_end()
1081: ** routine undoes the effect of sqlite3_os_init(). Typical tasks
1082: ** performed by these routines include allocation or deallocation
1083: ** of static resources, initialization of global variables,
1084: ** setting up a default [sqlite3_vfs] module, or setting up
1085: ** a default configuration using [sqlite3_config()].
1086: **
1087: ** The application should never invoke either sqlite3_os_init()
1088: ** or sqlite3_os_end() directly. The application should only invoke
1089: ** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init()
1090: ** interface is called automatically by sqlite3_initialize() and
1091: ** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate
1092: ** implementations for sqlite3_os_init() and sqlite3_os_end()
1093: ** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
1094: ** When [custom builds | built for other platforms]
1095: ** (using the [SQLITE_OS_OTHER=1] compile-time
1096: ** option) the application must supply a suitable implementation for
1097: ** sqlite3_os_init() and sqlite3_os_end(). An application-supplied
1098: ** implementation of sqlite3_os_init() or sqlite3_os_end()
1099: ** must return [SQLITE_OK] on success and some other [error code] upon
1100: ** failure.
1101: */
1102: SQLITE_API int sqlite3_initialize(void);
1103: SQLITE_API int sqlite3_shutdown(void);
1104: SQLITE_API int sqlite3_os_init(void);
1105: SQLITE_API int sqlite3_os_end(void);
1106:
1107: /*
1108: ** CAPI3REF: Configuring The SQLite Library
1109: **
1110: ** The sqlite3_config() interface is used to make global configuration
1111: ** changes to SQLite in order to tune SQLite to the specific needs of
1112: ** the application. The default configuration is recommended for most
1113: ** applications and so this routine is usually not necessary. It is
1114: ** provided to support rare applications with unusual needs.
1115: **
1116: ** The sqlite3_config() interface is not threadsafe. The application
1117: ** must insure that no other SQLite interfaces are invoked by other
1118: ** threads while sqlite3_config() is running. Furthermore, sqlite3_config()
1119: ** may only be invoked prior to library initialization using
1120: ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
1121: ** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
1122: ** [sqlite3_shutdown()] then it will return SQLITE_MISUSE.
1123: ** Note, however, that ^sqlite3_config() can be called as part of the
1124: ** implementation of an application-defined [sqlite3_os_init()].
1125: **
1126: ** The first argument to sqlite3_config() is an integer
1127: ** [configuration option] that determines
1128: ** what property of SQLite is to be configured. Subsequent arguments
1129: ** vary depending on the [configuration option]
1130: ** in the first argument.
1131: **
1132: ** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
1133: ** ^If the option is unknown or SQLite is unable to set the option
1134: ** then this routine returns a non-zero [error code].
1135: */
1136: SQLITE_API int sqlite3_config(int, ...);
1137:
1138: /*
1139: ** CAPI3REF: Configure database connections
1140: **
1141: ** The sqlite3_db_config() interface is used to make configuration
1142: ** changes to a [database connection]. The interface is similar to
1143: ** [sqlite3_config()] except that the changes apply to a single
1144: ** [database connection] (specified in the first argument).
1145: **
1146: ** The second argument to sqlite3_db_config(D,V,...) is the
1147: ** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code
1148: ** that indicates what aspect of the [database connection] is being configured.
1149: ** Subsequent arguments vary depending on the configuration verb.
1150: **
1151: ** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
1152: ** the call is considered successful.
1153: */
1154: SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...);
1155:
1156: /*
1157: ** CAPI3REF: Memory Allocation Routines
1158: **
1159: ** An instance of this object defines the interface between SQLite
1160: ** and low-level memory allocation routines.
1161: **
1162: ** This object is used in only one place in the SQLite interface.
1163: ** A pointer to an instance of this object is the argument to
1164: ** [sqlite3_config()] when the configuration option is
1165: ** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].
1166: ** By creating an instance of this object
1167: ** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
1168: ** during configuration, an application can specify an alternative
1169: ** memory allocation subsystem for SQLite to use for all of its
1170: ** dynamic memory needs.
1171: **
1172: ** Note that SQLite comes with several [built-in memory allocators]
1173: ** that are perfectly adequate for the overwhelming majority of applications
1174: ** and that this object is only useful to a tiny minority of applications
1175: ** with specialized memory allocation requirements. This object is
1176: ** also used during testing of SQLite in order to specify an alternative
1177: ** memory allocator that simulates memory out-of-memory conditions in
1178: ** order to verify that SQLite recovers gracefully from such
1179: ** conditions.
1180: **
1181: ** The xMalloc and xFree methods must work like the
1182: ** malloc() and free() functions from the standard C library.
1183: ** The xRealloc method must work like realloc() from the standard C library
1184: ** with the exception that if the second argument to xRealloc is zero,
1185: ** xRealloc must be a no-op - it must not perform any allocation or
1186: ** deallocation. ^SQLite guarantees that the second argument to
1187: ** xRealloc is always a value returned by a prior call to xRoundup.
1188: ** And so in cases where xRoundup always returns a positive number,
1189: ** xRealloc can perform exactly as the standard library realloc() and
1190: ** still be in compliance with this specification.
1191: **
1192: ** xSize should return the allocated size of a memory allocation
1193: ** previously obtained from xMalloc or xRealloc. The allocated size
1194: ** is always at least as big as the requested size but may be larger.
1195: **
1196: ** The xRoundup method returns what would be the allocated size of
1197: ** a memory allocation given a particular requested size. Most memory
1198: ** allocators round up memory allocations at least to the next multiple
1199: ** of 8. Some allocators round up to a larger multiple or to a power of 2.
1200: ** Every memory allocation request coming in through [sqlite3_malloc()]
1201: ** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0,
1202: ** that causes the corresponding memory allocation to fail.
1203: **
1204: ** The xInit method initializes the memory allocator. (For example,
1205: ** it might allocate any require mutexes or initialize internal data
1206: ** structures. The xShutdown method is invoked (indirectly) by
1207: ** [sqlite3_shutdown()] and should deallocate any resources acquired
1208: ** by xInit. The pAppData pointer is used as the only parameter to
1209: ** xInit and xShutdown.
1210: **
1211: ** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes
1212: ** the xInit method, so the xInit method need not be threadsafe. The
1213: ** xShutdown method is only called from [sqlite3_shutdown()] so it does
1214: ** not need to be threadsafe either. For all other methods, SQLite
1215: ** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
1216: ** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
1217: ** it is by default) and so the methods are automatically serialized.
1218: ** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
1219: ** methods must be threadsafe or else make their own arrangements for
1220: ** serialization.
1221: **
1222: ** SQLite will never invoke xInit() more than once without an intervening
1223: ** call to xShutdown().
1224: */
1225: typedef struct sqlite3_mem_methods sqlite3_mem_methods;
1226: struct sqlite3_mem_methods {
1227: void *(*xMalloc)(int); /* Memory allocation function */
1228: void (*xFree)(void*); /* Free a prior allocation */
1229: void *(*xRealloc)(void*,int); /* Resize an allocation */
1230: int (*xSize)(void*); /* Return the size of an allocation */
1231: int (*xRoundup)(int); /* Round up request size to allocation size */
1232: int (*xInit)(void*); /* Initialize the memory allocator */
1233: void (*xShutdown)(void*); /* Deinitialize the memory allocator */
1234: void *pAppData; /* Argument to xInit() and xShutdown() */
1235: };
1236:
1237: /*
1238: ** CAPI3REF: Configuration Options
1239: ** KEYWORDS: {configuration option}
1240: **
1241: ** These constants are the available integer configuration options that
1242: ** can be passed as the first argument to the [sqlite3_config()] interface.
1243: **
1244: ** New configuration options may be added in future releases of SQLite.
1245: ** Existing configuration options might be discontinued. Applications
1246: ** should check the return code from [sqlite3_config()] to make sure that
1247: ** the call worked. The [sqlite3_config()] interface will return a
1248: ** non-zero [error code] if a discontinued or unsupported configuration option
1249: ** is invoked.
1250: **
1251: ** <dl>
1252: ** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
1253: ** <dd>There are no arguments to this option. ^This option sets the
1254: ** [threading mode] to Single-thread. In other words, it disables
1255: ** all mutexing and puts SQLite into a mode where it can only be used
1256: ** by a single thread. ^If SQLite is compiled with
1257: ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1258: ** it is not possible to change the [threading mode] from its default
1259: ** value of Single-thread and so [sqlite3_config()] will return
1260: ** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
1261: ** configuration option.</dd>
1262: **
1263: ** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt>
1264: ** <dd>There are no arguments to this option. ^This option sets the
1265: ** [threading mode] to Multi-thread. In other words, it disables
1266: ** mutexing on [database connection] and [prepared statement] objects.
1267: ** The application is responsible for serializing access to
1268: ** [database connections] and [prepared statements]. But other mutexes
1269: ** are enabled so that SQLite will be safe to use in a multi-threaded
1270: ** environment as long as no two threads attempt to use the same
1271: ** [database connection] at the same time. ^If SQLite is compiled with
1272: ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1273: ** it is not possible to set the Multi-thread [threading mode] and
1274: ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1275: ** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
1276: **
1277: ** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt>
1278: ** <dd>There are no arguments to this option. ^This option sets the
1279: ** [threading mode] to Serialized. In other words, this option enables
1280: ** all mutexes including the recursive
1281: ** mutexes on [database connection] and [prepared statement] objects.
1282: ** In this mode (which is the default when SQLite is compiled with
1283: ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
1284: ** to [database connections] and [prepared statements] so that the
1285: ** application is free to use the same [database connection] or the
1286: ** same [prepared statement] in different threads at the same time.
1287: ** ^If SQLite is compiled with
1288: ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1289: ** it is not possible to set the Serialized [threading mode] and
1290: ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1291: ** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
1292: **
1293: ** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt>
1294: ** <dd> ^(This option takes a single argument which is a pointer to an
1295: ** instance of the [sqlite3_mem_methods] structure. The argument specifies
1296: ** alternative low-level memory allocation routines to be used in place of
1297: ** the memory allocation routines built into SQLite.)^ ^SQLite makes
1298: ** its own private copy of the content of the [sqlite3_mem_methods] structure
1299: ** before the [sqlite3_config()] call returns.</dd>
1300: **
1301: ** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt>
1302: ** <dd> ^(This option takes a single argument which is a pointer to an
1303: ** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods]
1304: ** structure is filled with the currently defined memory allocation routines.)^
1305: ** This option can be used to overload the default memory allocation
1306: ** routines with a wrapper that simulations memory allocation failure or
1307: ** tracks memory usage, for example. </dd>
1308: **
1309: ** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt>
1310: ** <dd> ^This option takes single argument of type int, interpreted as a
1311: ** boolean, which enables or disables the collection of memory allocation
1312: ** statistics. ^(When memory allocation statistics are disabled, the
1313: ** following SQLite interfaces become non-operational:
1314: ** <ul>
1315: ** <li> [sqlite3_memory_used()]
1316: ** <li> [sqlite3_memory_highwater()]
1317: ** <li> [sqlite3_soft_heap_limit64()]
1318: ** <li> [sqlite3_status()]
1319: ** </ul>)^
1320: ** ^Memory allocation statistics are enabled by default unless SQLite is
1321: ** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
1322: ** allocation statistics are disabled by default.
1323: ** </dd>
1324: **
1325: ** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt>
1326: ** <dd> ^This option specifies a static memory buffer that SQLite can use for
1327: ** scratch memory. There are three arguments: A pointer an 8-byte
1328: ** aligned memory buffer from which the scratch allocations will be
1329: ** drawn, the size of each scratch allocation (sz),
1330: ** and the maximum number of scratch allocations (N). The sz
1331: ** argument must be a multiple of 16.
1332: ** The first argument must be a pointer to an 8-byte aligned buffer
1333: ** of at least sz*N bytes of memory.
1334: ** ^SQLite will use no more than two scratch buffers per thread. So
1335: ** N should be set to twice the expected maximum number of threads.
1336: ** ^SQLite will never require a scratch buffer that is more than 6
1337: ** times the database page size. ^If SQLite needs needs additional
1338: ** scratch memory beyond what is provided by this configuration option, then
1339: ** [sqlite3_malloc()] will be used to obtain the memory needed.</dd>
1340: **
1341: ** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>
1342: ** <dd> ^This option specifies a static memory buffer that SQLite can use for
1343: ** the database page cache with the default page cache implementation.
1344: ** This configuration should not be used if an application-define page
1345: ** cache implementation is loaded using the SQLITE_CONFIG_PCACHE option.
1346: ** There are three arguments to this option: A pointer to 8-byte aligned
1347: ** memory, the size of each page buffer (sz), and the number of pages (N).
1348: ** The sz argument should be the size of the largest database page
1349: ** (a power of two between 512 and 32768) plus a little extra for each
1350: ** page header. ^The page header size is 20 to 40 bytes depending on
1351: ** the host architecture. ^It is harmless, apart from the wasted memory,
1352: ** to make sz a little too large. The first
1353: ** argument should point to an allocation of at least sz*N bytes of memory.
1354: ** ^SQLite will use the memory provided by the first argument to satisfy its
1355: ** memory needs for the first N pages that it adds to cache. ^If additional
1356: ** page cache memory is needed beyond what is provided by this option, then
1357: ** SQLite goes to [sqlite3_malloc()] for the additional storage space.
1358: ** The pointer in the first argument must
1359: ** be aligned to an 8-byte boundary or subsequent behavior of SQLite
1360: ** will be undefined.</dd>
1361: **
1362: ** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt>
1363: ** <dd> ^This option specifies a static memory buffer that SQLite will use
1364: ** for all of its dynamic memory allocation needs beyond those provided
1365: ** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE].
1366: ** There are three arguments: An 8-byte aligned pointer to the memory,
1367: ** the number of bytes in the memory buffer, and the minimum allocation size.
1368: ** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
1369: ** to using its default memory allocator (the system malloc() implementation),
1370: ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the
1371: ** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or
1372: ** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory
1373: ** allocator is engaged to handle all of SQLites memory allocation needs.
1374: ** The first pointer (the memory pointer) must be aligned to an 8-byte
1375: ** boundary or subsequent behavior of SQLite will be undefined.
1376: ** The minimum allocation size is capped at 2^12. Reasonable values
1377: ** for the minimum allocation size are 2^5 through 2^8.</dd>
1378: **
1379: ** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt>
1380: ** <dd> ^(This option takes a single argument which is a pointer to an
1381: ** instance of the [sqlite3_mutex_methods] structure. The argument specifies
1382: ** alternative low-level mutex routines to be used in place
1383: ** the mutex routines built into SQLite.)^ ^SQLite makes a copy of the
1384: ** content of the [sqlite3_mutex_methods] structure before the call to
1385: ** [sqlite3_config()] returns. ^If SQLite is compiled with
1386: ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1387: ** the entire mutexing subsystem is omitted from the build and hence calls to
1388: ** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
1389: ** return [SQLITE_ERROR].</dd>
1390: **
1391: ** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt>
1392: ** <dd> ^(This option takes a single argument which is a pointer to an
1393: ** instance of the [sqlite3_mutex_methods] structure. The
1394: ** [sqlite3_mutex_methods]
1395: ** structure is filled with the currently defined mutex routines.)^
1396: ** This option can be used to overload the default mutex allocation
1397: ** routines with a wrapper used to track mutex usage for performance
1398: ** profiling or testing, for example. ^If SQLite is compiled with
1399: ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1400: ** the entire mutexing subsystem is omitted from the build and hence calls to
1401: ** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
1402: ** return [SQLITE_ERROR].</dd>
1403: **
1404: ** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt>
1405: ** <dd> ^(This option takes two arguments that determine the default
1406: ** memory allocation for the lookaside memory allocator on each
1407: ** [database connection]. The first argument is the
1408: ** size of each lookaside buffer slot and the second is the number of
1409: ** slots allocated to each database connection.)^ ^(This option sets the
1410: ** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
1411: ** verb to [sqlite3_db_config()] can be used to change the lookaside
1412: ** configuration on individual connections.)^ </dd>
1413: **
1414: ** [[SQLITE_CONFIG_PCACHE]] <dt>SQLITE_CONFIG_PCACHE</dt>
1415: ** <dd> ^(This option takes a single argument which is a pointer to
1416: ** an [sqlite3_pcache_methods] object. This object specifies the interface
1417: ** to a custom page cache implementation.)^ ^SQLite makes a copy of the
1418: ** object and uses it for page cache memory allocations.</dd>
1419: **
1420: ** [[SQLITE_CONFIG_GETPCACHE]] <dt>SQLITE_CONFIG_GETPCACHE</dt>
1421: ** <dd> ^(This option takes a single argument which is a pointer to an
1422: ** [sqlite3_pcache_methods] object. SQLite copies of the current
1423: ** page cache implementation into that object.)^ </dd>
1424: **
1425: ** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>
1426: ** <dd> ^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
1427: ** function with a call signature of void(*)(void*,int,const char*),
1428: ** and a pointer to void. ^If the function pointer is not NULL, it is
1429: ** invoked by [sqlite3_log()] to process each logging event. ^If the
1430: ** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
1431: ** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
1432: ** passed through as the first parameter to the application-defined logger
1433: ** function whenever that function is invoked. ^The second parameter to
1434: ** the logger function is a copy of the first parameter to the corresponding
1435: ** [sqlite3_log()] call and is intended to be a [result code] or an
1436: ** [extended result code]. ^The third parameter passed to the logger is
1437: ** log message after formatting via [sqlite3_snprintf()].
1438: ** The SQLite logging interface is not reentrant; the logger function
1439: ** supplied by the application must not invoke any SQLite interface.
1440: ** In a multi-threaded application, the application-defined logger
1441: ** function must be threadsafe. </dd>
1442: **
1443: ** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI
1444: ** <dd> This option takes a single argument of type int. If non-zero, then
1445: ** URI handling is globally enabled. If the parameter is zero, then URI handling
1446: ** is globally disabled. If URI handling is globally enabled, all filenames
1447: ** passed to [sqlite3_open()], [sqlite3_open_v2()], [sqlite3_open16()] or
1448: ** specified as part of [ATTACH] commands are interpreted as URIs, regardless
1449: ** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
1450: ** connection is opened. If it is globally disabled, filenames are
1451: ** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
1452: ** database connection is opened. By default, URI handling is globally
1453: ** disabled. The default value may be changed by compiling with the
1454: ** [SQLITE_USE_URI] symbol defined.
1455: ** </dl>
1456: */
1457: #define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */
1458: #define SQLITE_CONFIG_MULTITHREAD 2 /* nil */
1459: #define SQLITE_CONFIG_SERIALIZED 3 /* nil */
1460: #define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */
1461: #define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */
1462: #define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */
1463: #define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */
1464: #define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */
1465: #define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */
1466: #define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */
1467: #define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */
1468: /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */
1469: #define SQLITE_CONFIG_LOOKASIDE 13 /* int int */
1470: #define SQLITE_CONFIG_PCACHE 14 /* sqlite3_pcache_methods* */
1471: #define SQLITE_CONFIG_GETPCACHE 15 /* sqlite3_pcache_methods* */
1472: #define SQLITE_CONFIG_LOG 16 /* xFunc, void* */
1473: #define SQLITE_CONFIG_URI 17 /* int */
1474:
1475: /*
1476: ** CAPI3REF: Database Connection Configuration Options
1477: **
1478: ** These constants are the available integer configuration options that
1479: ** can be passed as the second argument to the [sqlite3_db_config()] interface.
1480: **
1481: ** New configuration options may be added in future releases of SQLite.
1482: ** Existing configuration options might be discontinued. Applications
1483: ** should check the return code from [sqlite3_db_config()] to make sure that
1484: ** the call worked. ^The [sqlite3_db_config()] interface will return a
1485: ** non-zero [error code] if a discontinued or unsupported configuration option
1486: ** is invoked.
1487: **
1488: ** <dl>
1489: ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
1490: ** <dd> ^This option takes three additional arguments that determine the
1491: ** [lookaside memory allocator] configuration for the [database connection].
1492: ** ^The first argument (the third parameter to [sqlite3_db_config()] is a
1493: ** pointer to a memory buffer to use for lookaside memory.
1494: ** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
1495: ** may be NULL in which case SQLite will allocate the
1496: ** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
1497: ** size of each lookaside buffer slot. ^The third argument is the number of
1498: ** slots. The size of the buffer in the first argument must be greater than
1499: ** or equal to the product of the second and third arguments. The buffer
1500: ** must be aligned to an 8-byte boundary. ^If the second argument to
1501: ** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
1502: ** rounded down to the next smaller multiple of 8. ^(The lookaside memory
1503: ** configuration for a database connection can only be changed when that
1504: ** connection is not currently using lookaside memory, or in other words
1505: ** when the "current value" returned by
1506: ** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero.
1507: ** Any attempt to change the lookaside memory configuration when lookaside
1508: ** memory is in use leaves the configuration unchanged and returns
1509: ** [SQLITE_BUSY].)^</dd>
1510: **
1511: ** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
1512: ** <dd> ^This option is used to enable or disable the enforcement of
1513: ** [foreign key constraints]. There should be two additional arguments.
1514: ** The first argument is an integer which is 0 to disable FK enforcement,
1515: ** positive to enable FK enforcement or negative to leave FK enforcement
1516: ** unchanged. The second parameter is a pointer to an integer into which
1517: ** is written 0 or 1 to indicate whether FK enforcement is off or on
1518: ** following this call. The second parameter may be a NULL pointer, in
1519: ** which case the FK enforcement setting is not reported back. </dd>
1520: **
1521: ** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
1522: ** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
1523: ** There should be two additional arguments.
1524: ** The first argument is an integer which is 0 to disable triggers,
1525: ** positive to enable triggers or negative to leave the setting unchanged.
1526: ** The second parameter is a pointer to an integer into which
1527: ** is written 0 or 1 to indicate whether triggers are disabled or enabled
1528: ** following this call. The second parameter may be a NULL pointer, in
1529: ** which case the trigger setting is not reported back. </dd>
1530: **
1531: ** </dl>
1532: */
1533: #define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */
1534: #define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */
1535: #define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */
1536:
1537:
1538: /*
1539: ** CAPI3REF: Enable Or Disable Extended Result Codes
1540: **
1541: ** ^The sqlite3_extended_result_codes() routine enables or disables the
1542: ** [extended result codes] feature of SQLite. ^The extended result
1543: ** codes are disabled by default for historical compatibility.
1544: */
1545: SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff);
1546:
1547: /*
1548: ** CAPI3REF: Last Insert Rowid
1549: **
1550: ** ^Each entry in an SQLite table has a unique 64-bit signed
1551: ** integer key called the [ROWID | "rowid"]. ^The rowid is always available
1552: ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
1553: ** names are not also used by explicitly declared columns. ^If
1554: ** the table has a column of type [INTEGER PRIMARY KEY] then that column
1555: ** is another alias for the rowid.
1556: **
1557: ** ^This routine returns the [rowid] of the most recent
1558: ** successful [INSERT] into the database from the [database connection]
1559: ** in the first argument. ^As of SQLite version 3.7.7, this routines
1560: ** records the last insert rowid of both ordinary tables and [virtual tables].
1561: ** ^If no successful [INSERT]s
1562: ** have ever occurred on that database connection, zero is returned.
1563: **
1564: ** ^(If an [INSERT] occurs within a trigger or within a [virtual table]
1565: ** method, then this routine will return the [rowid] of the inserted
1566: ** row as long as the trigger or virtual table method is running.
1567: ** But once the trigger or virtual table method ends, the value returned
1568: ** by this routine reverts to what it was before the trigger or virtual
1569: ** table method began.)^
1570: **
1571: ** ^An [INSERT] that fails due to a constraint violation is not a
1572: ** successful [INSERT] and does not change the value returned by this
1573: ** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
1574: ** and INSERT OR ABORT make no changes to the return value of this
1575: ** routine when their insertion fails. ^(When INSERT OR REPLACE
1576: ** encounters a constraint violation, it does not fail. The
1577: ** INSERT continues to completion after deleting rows that caused
1578: ** the constraint problem so INSERT OR REPLACE will always change
1579: ** the return value of this interface.)^
1580: **
1581: ** ^For the purposes of this routine, an [INSERT] is considered to
1582: ** be successful even if it is subsequently rolled back.
1583: **
1584: ** This function is accessible to SQL statements via the
1585: ** [last_insert_rowid() SQL function].
1586: **
1587: ** If a separate thread performs a new [INSERT] on the same
1588: ** database connection while the [sqlite3_last_insert_rowid()]
1589: ** function is running and thus changes the last insert [rowid],
1590: ** then the value returned by [sqlite3_last_insert_rowid()] is
1591: ** unpredictable and might not equal either the old or the new
1592: ** last insert [rowid].
1593: */
1594: SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
1595:
1596: /*
1597: ** CAPI3REF: Count The Number Of Rows Modified
1598: **
1599: ** ^This function returns the number of database rows that were changed
1600: ** or inserted or deleted by the most recently completed SQL statement
1601: ** on the [database connection] specified by the first parameter.
1602: ** ^(Only changes that are directly specified by the [INSERT], [UPDATE],
1603: ** or [DELETE] statement are counted. Auxiliary changes caused by
1604: ** triggers or [foreign key actions] are not counted.)^ Use the
1605: ** [sqlite3_total_changes()] function to find the total number of changes
1606: ** including changes caused by triggers and foreign key actions.
1607: **
1608: ** ^Changes to a view that are simulated by an [INSTEAD OF trigger]
1609: ** are not counted. Only real table changes are counted.
1610: **
1611: ** ^(A "row change" is a change to a single row of a single table
1612: ** caused by an INSERT, DELETE, or UPDATE statement. Rows that
1613: ** are changed as side effects of [REPLACE] constraint resolution,
1614: ** rollback, ABORT processing, [DROP TABLE], or by any other
1615: ** mechanisms do not count as direct row changes.)^
1616: **
1617: ** A "trigger context" is a scope of execution that begins and
1618: ** ends with the script of a [CREATE TRIGGER | trigger].
1619: ** Most SQL statements are
1620: ** evaluated outside of any trigger. This is the "top level"
1621: ** trigger context. If a trigger fires from the top level, a
1622: ** new trigger context is entered for the duration of that one
1623: ** trigger. Subtriggers create subcontexts for their duration.
1624: **
1625: ** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does
1626: ** not create a new trigger context.
1627: **
1628: ** ^This function returns the number of direct row changes in the
1629: ** most recent INSERT, UPDATE, or DELETE statement within the same
1630: ** trigger context.
1631: **
1632: ** ^Thus, when called from the top level, this function returns the
1633: ** number of changes in the most recent INSERT, UPDATE, or DELETE
1634: ** that also occurred at the top level. ^(Within the body of a trigger,
1635: ** the sqlite3_changes() interface can be called to find the number of
1636: ** changes in the most recently completed INSERT, UPDATE, or DELETE
1637: ** statement within the body of the same trigger.
1638: ** However, the number returned does not include changes
1639: ** caused by subtriggers since those have their own context.)^
1640: **
1641: ** See also the [sqlite3_total_changes()] interface, the
1642: ** [count_changes pragma], and the [changes() SQL function].
1643: **
1644: ** If a separate thread makes changes on the same database connection
1645: ** while [sqlite3_changes()] is running then the value returned
1646: ** is unpredictable and not meaningful.
1647: */
1648: SQLITE_API int sqlite3_changes(sqlite3*);
1649:
1650: /*
1651: ** CAPI3REF: Total Number Of Rows Modified
1652: **
1653: ** ^This function returns the number of row changes caused by [INSERT],
1654: ** [UPDATE] or [DELETE] statements since the [database connection] was opened.
1655: ** ^(The count returned by sqlite3_total_changes() includes all changes
1656: ** from all [CREATE TRIGGER | trigger] contexts and changes made by
1657: ** [foreign key actions]. However,
1658: ** the count does not include changes used to implement [REPLACE] constraints,
1659: ** do rollbacks or ABORT processing, or [DROP TABLE] processing. The
1660: ** count does not include rows of views that fire an [INSTEAD OF trigger],
1661: ** though if the INSTEAD OF trigger makes changes of its own, those changes
1662: ** are counted.)^
1663: ** ^The sqlite3_total_changes() function counts the changes as soon as
1664: ** the statement that makes them is completed (when the statement handle
1665: ** is passed to [sqlite3_reset()] or [sqlite3_finalize()]).
1666: **
1667: ** See also the [sqlite3_changes()] interface, the
1668: ** [count_changes pragma], and the [total_changes() SQL function].
1669: **
1670: ** If a separate thread makes changes on the same database connection
1671: ** while [sqlite3_total_changes()] is running then the value
1672: ** returned is unpredictable and not meaningful.
1673: */
1674: SQLITE_API int sqlite3_total_changes(sqlite3*);
1675:
1676: /*
1677: ** CAPI3REF: Interrupt A Long-Running Query
1678: **
1679: ** ^This function causes any pending database operation to abort and
1680: ** return at its earliest opportunity. This routine is typically
1681: ** called in response to a user action such as pressing "Cancel"
1682: ** or Ctrl-C where the user wants a long query operation to halt
1683: ** immediately.
1684: **
1685: ** ^It is safe to call this routine from a thread different from the
1686: ** thread that is currently running the database operation. But it
1687: ** is not safe to call this routine with a [database connection] that
1688: ** is closed or might close before sqlite3_interrupt() returns.
1689: **
1690: ** ^If an SQL operation is very nearly finished at the time when
1691: ** sqlite3_interrupt() is called, then it might not have an opportunity
1692: ** to be interrupted and might continue to completion.
1693: **
1694: ** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
1695: ** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
1696: ** that is inside an explicit transaction, then the entire transaction
1697: ** will be rolled back automatically.
1698: **
1699: ** ^The sqlite3_interrupt(D) call is in effect until all currently running
1700: ** SQL statements on [database connection] D complete. ^Any new SQL statements
1701: ** that are started after the sqlite3_interrupt() call and before the
1702: ** running statements reaches zero are interrupted as if they had been
1703: ** running prior to the sqlite3_interrupt() call. ^New SQL statements
1704: ** that are started after the running statement count reaches zero are
1705: ** not effected by the sqlite3_interrupt().
1706: ** ^A call to sqlite3_interrupt(D) that occurs when there are no running
1707: ** SQL statements is a no-op and has no effect on SQL statements
1708: ** that are started after the sqlite3_interrupt() call returns.
1709: **
1710: ** If the database connection closes while [sqlite3_interrupt()]
1711: ** is running then bad things will likely happen.
1712: */
1713: SQLITE_API void sqlite3_interrupt(sqlite3*);
1714:
1715: /*
1716: ** CAPI3REF: Determine If An SQL Statement Is Complete
1717: **
1718: ** These routines are useful during command-line input to determine if the
1719: ** currently entered text seems to form a complete SQL statement or
1720: ** if additional input is needed before sending the text into
1721: ** SQLite for parsing. ^These routines return 1 if the input string
1722: ** appears to be a complete SQL statement. ^A statement is judged to be
1723: ** complete if it ends with a semicolon token and is not a prefix of a
1724: ** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within
1725: ** string literals or quoted identifier names or comments are not
1726: ** independent tokens (they are part of the token in which they are
1727: ** embedded) and thus do not count as a statement terminator. ^Whitespace
1728: ** and comments that follow the final semicolon are ignored.
1729: **
1730: ** ^These routines return 0 if the statement is incomplete. ^If a
1731: ** memory allocation fails, then SQLITE_NOMEM is returned.
1732: **
1733: ** ^These routines do not parse the SQL statements thus
1734: ** will not detect syntactically incorrect SQL.
1735: **
1736: ** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior
1737: ** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
1738: ** automatically by sqlite3_complete16(). If that initialization fails,
1739: ** then the return value from sqlite3_complete16() will be non-zero
1740: ** regardless of whether or not the input SQL is complete.)^
1741: **
1742: ** The input to [sqlite3_complete()] must be a zero-terminated
1743: ** UTF-8 string.
1744: **
1745: ** The input to [sqlite3_complete16()] must be a zero-terminated
1746: ** UTF-16 string in native byte order.
1747: */
1748: SQLITE_API int sqlite3_complete(const char *sql);
1749: SQLITE_API int sqlite3_complete16(const void *sql);
1750:
1751: /*
1752: ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
1753: **
1754: ** ^This routine sets a callback function that might be invoked whenever
1755: ** an attempt is made to open a database table that another thread
1756: ** or process has locked.
1757: **
1758: ** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]
1759: ** is returned immediately upon encountering the lock. ^If the busy callback
1760: ** is not NULL, then the callback might be invoked with two arguments.
1761: **
1762: ** ^The first argument to the busy handler is a copy of the void* pointer which
1763: ** is the third argument to sqlite3_busy_handler(). ^The second argument to
1764: ** the busy handler callback is the number of times that the busy handler has
1765: ** been invoked for this locking event. ^If the
1766: ** busy callback returns 0, then no additional attempts are made to
1767: ** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned.
1768: ** ^If the callback returns non-zero, then another attempt
1769: ** is made to open the database for reading and the cycle repeats.
1770: **
1771: ** The presence of a busy handler does not guarantee that it will be invoked
1772: ** when there is lock contention. ^If SQLite determines that invoking the busy
1773: ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
1774: ** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler.
1775: ** Consider a scenario where one process is holding a read lock that
1776: ** it is trying to promote to a reserved lock and
1777: ** a second process is holding a reserved lock that it is trying
1778: ** to promote to an exclusive lock. The first process cannot proceed
1779: ** because it is blocked by the second and the second process cannot
1780: ** proceed because it is blocked by the first. If both processes
1781: ** invoke the busy handlers, neither will make any progress. Therefore,
1782: ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
1783: ** will induce the first process to release its read lock and allow
1784: ** the second process to proceed.
1785: **
1786: ** ^The default busy callback is NULL.
1787: **
1788: ** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED]
1789: ** when SQLite is in the middle of a large transaction where all the
1790: ** changes will not fit into the in-memory cache. SQLite will
1791: ** already hold a RESERVED lock on the database file, but it needs
1792: ** to promote this lock to EXCLUSIVE so that it can spill cache
1793: ** pages into the database file without harm to concurrent
1794: ** readers. ^If it is unable to promote the lock, then the in-memory
1795: ** cache will be left in an inconsistent state and so the error
1796: ** code is promoted from the relatively benign [SQLITE_BUSY] to
1797: ** the more severe [SQLITE_IOERR_BLOCKED]. ^This error code promotion
1798: ** forces an automatic rollback of the changes. See the
1799: ** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError">
1800: ** CorruptionFollowingBusyError</a> wiki page for a discussion of why
1801: ** this is important.
1802: **
1803: ** ^(There can only be a single busy handler defined for each
1804: ** [database connection]. Setting a new busy handler clears any
1805: ** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()]
1806: ** will also set or clear the busy handler.
1807: **
1808: ** The busy callback should not take any actions which modify the
1809: ** database connection that invoked the busy handler. Any such actions
1810: ** result in undefined behavior.
1811: **
1812: ** A busy handler must not close the database connection
1813: ** or [prepared statement] that invoked the busy handler.
1814: */
1815: SQLITE_API int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*);
1816:
1817: /*
1818: ** CAPI3REF: Set A Busy Timeout
1819: **
1820: ** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
1821: ** for a specified amount of time when a table is locked. ^The handler
1822: ** will sleep multiple times until at least "ms" milliseconds of sleeping
1823: ** have accumulated. ^After at least "ms" milliseconds of sleeping,
1824: ** the handler returns 0 which causes [sqlite3_step()] to return
1825: ** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED].
1826: **
1827: ** ^Calling this routine with an argument less than or equal to zero
1828: ** turns off all busy handlers.
1829: **
1830: ** ^(There can only be a single busy handler for a particular
1831: ** [database connection] any any given moment. If another busy handler
1832: ** was defined (using [sqlite3_busy_handler()]) prior to calling
1833: ** this routine, that other busy handler is cleared.)^
1834: */
1835: SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms);
1836:
1837: /*
1838: ** CAPI3REF: Convenience Routines For Running Queries
1839: **
1840: ** This is a legacy interface that is preserved for backwards compatibility.
1841: ** Use of this interface is not recommended.
1842: **
1843: ** Definition: A <b>result table</b> is memory data structure created by the
1844: ** [sqlite3_get_table()] interface. A result table records the
1845: ** complete query results from one or more queries.
1846: **
1847: ** The table conceptually has a number of rows and columns. But
1848: ** these numbers are not part of the result table itself. These
1849: ** numbers are obtained separately. Let N be the number of rows
1850: ** and M be the number of columns.
1851: **
1852: ** A result table is an array of pointers to zero-terminated UTF-8 strings.
1853: ** There are (N+1)*M elements in the array. The first M pointers point
1854: ** to zero-terminated strings that contain the names of the columns.
1855: ** The remaining entries all point to query results. NULL values result
1856: ** in NULL pointers. All other values are in their UTF-8 zero-terminated
1857: ** string representation as returned by [sqlite3_column_text()].
1858: **
1859: ** A result table might consist of one or more memory allocations.
1860: ** It is not safe to pass a result table directly to [sqlite3_free()].
1861: ** A result table should be deallocated using [sqlite3_free_table()].
1862: **
1863: ** ^(As an example of the result table format, suppose a query result
1864: ** is as follows:
1865: **
1866: ** <blockquote><pre>
1867: ** Name | Age
1868: ** -----------------------
1869: ** Alice | 43
1870: ** Bob | 28
1871: ** Cindy | 21
1872: ** </pre></blockquote>
1873: **
1874: ** There are two column (M==2) and three rows (N==3). Thus the
1875: ** result table has 8 entries. Suppose the result table is stored
1876: ** in an array names azResult. Then azResult holds this content:
1877: **
1878: ** <blockquote><pre>
1879: ** azResult[0] = "Name";
1880: ** azResult[1] = "Age";
1881: ** azResult[2] = "Alice";
1882: ** azResult[3] = "43";
1883: ** azResult[4] = "Bob";
1884: ** azResult[5] = "28";
1885: ** azResult[6] = "Cindy";
1886: ** azResult[7] = "21";
1887: ** </pre></blockquote>)^
1888: **
1889: ** ^The sqlite3_get_table() function evaluates one or more
1890: ** semicolon-separated SQL statements in the zero-terminated UTF-8
1891: ** string of its 2nd parameter and returns a result table to the
1892: ** pointer given in its 3rd parameter.
1893: **
1894: ** After the application has finished with the result from sqlite3_get_table(),
1895: ** it must pass the result table pointer to sqlite3_free_table() in order to
1896: ** release the memory that was malloced. Because of the way the
1897: ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
1898: ** function must not try to call [sqlite3_free()] directly. Only
1899: ** [sqlite3_free_table()] is able to release the memory properly and safely.
1900: **
1901: ** The sqlite3_get_table() interface is implemented as a wrapper around
1902: ** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access
1903: ** to any internal data structures of SQLite. It uses only the public
1904: ** interface defined here. As a consequence, errors that occur in the
1905: ** wrapper layer outside of the internal [sqlite3_exec()] call are not
1906: ** reflected in subsequent calls to [sqlite3_errcode()] or
1907: ** [sqlite3_errmsg()].
1908: */
1909: SQLITE_API int sqlite3_get_table(
1910: sqlite3 *db, /* An open database */
1911: const char *zSql, /* SQL to be evaluated */
1912: char ***pazResult, /* Results of the query */
1913: int *pnRow, /* Number of result rows written here */
1914: int *pnColumn, /* Number of result columns written here */
1915: char **pzErrmsg /* Error msg written here */
1916: );
1917: SQLITE_API void sqlite3_free_table(char **result);
1918:
1919: /*
1920: ** CAPI3REF: Formatted String Printing Functions
1921: **
1922: ** These routines are work-alikes of the "printf()" family of functions
1923: ** from the standard C library.
1924: **
1925: ** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
1926: ** results into memory obtained from [sqlite3_malloc()].
1927: ** The strings returned by these two routines should be
1928: ** released by [sqlite3_free()]. ^Both routines return a
1929: ** NULL pointer if [sqlite3_malloc()] is unable to allocate enough
1930: ** memory to hold the resulting string.
1931: **
1932: ** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
1933: ** the standard C library. The result is written into the
1934: ** buffer supplied as the second parameter whose size is given by
1935: ** the first parameter. Note that the order of the
1936: ** first two parameters is reversed from snprintf().)^ This is an
1937: ** historical accident that cannot be fixed without breaking
1938: ** backwards compatibility. ^(Note also that sqlite3_snprintf()
1939: ** returns a pointer to its buffer instead of the number of
1940: ** characters actually written into the buffer.)^ We admit that
1941: ** the number of characters written would be a more useful return
1942: ** value but we cannot change the implementation of sqlite3_snprintf()
1943: ** now without breaking compatibility.
1944: **
1945: ** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
1946: ** guarantees that the buffer is always zero-terminated. ^The first
1947: ** parameter "n" is the total size of the buffer, including space for
1948: ** the zero terminator. So the longest string that can be completely
1949: ** written will be n-1 characters.
1950: **
1951: ** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
1952: **
1953: ** These routines all implement some additional formatting
1954: ** options that are useful for constructing SQL statements.
1955: ** All of the usual printf() formatting options apply. In addition, there
1956: ** is are "%q", "%Q", and "%z" options.
1957: **
1958: ** ^(The %q option works like %s in that it substitutes a null-terminated
1959: ** string from the argument list. But %q also doubles every '\'' character.
1960: ** %q is designed for use inside a string literal.)^ By doubling each '\''
1961: ** character it escapes that character and allows it to be inserted into
1962: ** the string.
1963: **
1964: ** For example, assume the string variable zText contains text as follows:
1965: **
1966: ** <blockquote><pre>
1967: ** char *zText = "It's a happy day!";
1968: ** </pre></blockquote>
1969: **
1970: ** One can use this text in an SQL statement as follows:
1971: **
1972: ** <blockquote><pre>
1973: ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText);
1974: ** sqlite3_exec(db, zSQL, 0, 0, 0);
1975: ** sqlite3_free(zSQL);
1976: ** </pre></blockquote>
1977: **
1978: ** Because the %q format string is used, the '\'' character in zText
1979: ** is escaped and the SQL generated is as follows:
1980: **
1981: ** <blockquote><pre>
1982: ** INSERT INTO table1 VALUES('It''s a happy day!')
1983: ** </pre></blockquote>
1984: **
1985: ** This is correct. Had we used %s instead of %q, the generated SQL
1986: ** would have looked like this:
1987: **
1988: ** <blockquote><pre>
1989: ** INSERT INTO table1 VALUES('It's a happy day!');
1990: ** </pre></blockquote>
1991: **
1992: ** This second example is an SQL syntax error. As a general rule you should
1993: ** always use %q instead of %s when inserting text into a string literal.
1994: **
1995: ** ^(The %Q option works like %q except it also adds single quotes around
1996: ** the outside of the total string. Additionally, if the parameter in the
1997: ** argument list is a NULL pointer, %Q substitutes the text "NULL" (without
1998: ** single quotes).)^ So, for example, one could say:
1999: **
2000: ** <blockquote><pre>
2001: ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText);
2002: ** sqlite3_exec(db, zSQL, 0, 0, 0);
2003: ** sqlite3_free(zSQL);
2004: ** </pre></blockquote>
2005: **
2006: ** The code above will render a correct SQL statement in the zSQL
2007: ** variable even if the zText variable is a NULL pointer.
2008: **
2009: ** ^(The "%z" formatting option works like "%s" but with the
2010: ** addition that after the string has been read and copied into
2011: ** the result, [sqlite3_free()] is called on the input string.)^
2012: */
2013: SQLITE_API char *sqlite3_mprintf(const char*,...);
2014: SQLITE_API char *sqlite3_vmprintf(const char*, va_list);
2015: SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...);
2016: SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list);
2017:
2018: /*
2019: ** CAPI3REF: Memory Allocation Subsystem
2020: **
2021: ** The SQLite core uses these three routines for all of its own
2022: ** internal memory allocation needs. "Core" in the previous sentence
2023: ** does not include operating-system specific VFS implementation. The
2024: ** Windows VFS uses native malloc() and free() for some operations.
2025: **
2026: ** ^The sqlite3_malloc() routine returns a pointer to a block
2027: ** of memory at least N bytes in length, where N is the parameter.
2028: ** ^If sqlite3_malloc() is unable to obtain sufficient free
2029: ** memory, it returns a NULL pointer. ^If the parameter N to
2030: ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
2031: ** a NULL pointer.
2032: **
2033: ** ^Calling sqlite3_free() with a pointer previously returned
2034: ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
2035: ** that it might be reused. ^The sqlite3_free() routine is
2036: ** a no-op if is called with a NULL pointer. Passing a NULL pointer
2037: ** to sqlite3_free() is harmless. After being freed, memory
2038: ** should neither be read nor written. Even reading previously freed
2039: ** memory might result in a segmentation fault or other severe error.
2040: ** Memory corruption, a segmentation fault, or other severe error
2041: ** might result if sqlite3_free() is called with a non-NULL pointer that
2042: ** was not obtained from sqlite3_malloc() or sqlite3_realloc().
2043: **
2044: ** ^(The sqlite3_realloc() interface attempts to resize a
2045: ** prior memory allocation to be at least N bytes, where N is the
2046: ** second parameter. The memory allocation to be resized is the first
2047: ** parameter.)^ ^ If the first parameter to sqlite3_realloc()
2048: ** is a NULL pointer then its behavior is identical to calling
2049: ** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc().
2050: ** ^If the second parameter to sqlite3_realloc() is zero or
2051: ** negative then the behavior is exactly the same as calling
2052: ** sqlite3_free(P) where P is the first parameter to sqlite3_realloc().
2053: ** ^sqlite3_realloc() returns a pointer to a memory allocation
2054: ** of at least N bytes in size or NULL if sufficient memory is unavailable.
2055: ** ^If M is the size of the prior allocation, then min(N,M) bytes
2056: ** of the prior allocation are copied into the beginning of buffer returned
2057: ** by sqlite3_realloc() and the prior allocation is freed.
2058: ** ^If sqlite3_realloc() returns NULL, then the prior allocation
2059: ** is not freed.
2060: **
2061: ** ^The memory returned by sqlite3_malloc() and sqlite3_realloc()
2062: ** is always aligned to at least an 8 byte boundary, or to a
2063: ** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
2064: ** option is used.
2065: **
2066: ** In SQLite version 3.5.0 and 3.5.1, it was possible to define
2067: ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in
2068: ** implementation of these routines to be omitted. That capability
2069: ** is no longer provided. Only built-in memory allocators can be used.
2070: **
2071: ** The Windows OS interface layer calls
2072: ** the system malloc() and free() directly when converting
2073: ** filenames between the UTF-8 encoding used by SQLite
2074: ** and whatever filename encoding is used by the particular Windows
2075: ** installation. Memory allocation errors are detected, but
2076: ** they are reported back as [SQLITE_CANTOPEN] or
2077: ** [SQLITE_IOERR] rather than [SQLITE_NOMEM].
2078: **
2079: ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
2080: ** must be either NULL or else pointers obtained from a prior
2081: ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
2082: ** not yet been released.
2083: **
2084: ** The application must not read or write any part of
2085: ** a block of memory after it has been released using
2086: ** [sqlite3_free()] or [sqlite3_realloc()].
2087: */
2088: SQLITE_API void *sqlite3_malloc(int);
2089: SQLITE_API void *sqlite3_realloc(void*, int);
2090: SQLITE_API void sqlite3_free(void*);
2091:
2092: /*
2093: ** CAPI3REF: Memory Allocator Statistics
2094: **
2095: ** SQLite provides these two interfaces for reporting on the status
2096: ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
2097: ** routines, which form the built-in memory allocation subsystem.
2098: **
2099: ** ^The [sqlite3_memory_used()] routine returns the number of bytes
2100: ** of memory currently outstanding (malloced but not freed).
2101: ** ^The [sqlite3_memory_highwater()] routine returns the maximum
2102: ** value of [sqlite3_memory_used()] since the high-water mark
2103: ** was last reset. ^The values returned by [sqlite3_memory_used()] and
2104: ** [sqlite3_memory_highwater()] include any overhead
2105: ** added by SQLite in its implementation of [sqlite3_malloc()],
2106: ** but not overhead added by the any underlying system library
2107: ** routines that [sqlite3_malloc()] may call.
2108: **
2109: ** ^The memory high-water mark is reset to the current value of
2110: ** [sqlite3_memory_used()] if and only if the parameter to
2111: ** [sqlite3_memory_highwater()] is true. ^The value returned
2112: ** by [sqlite3_memory_highwater(1)] is the high-water mark
2113: ** prior to the reset.
2114: */
2115: SQLITE_API sqlite3_int64 sqlite3_memory_used(void);
2116: SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
2117:
2118: /*
2119: ** CAPI3REF: Pseudo-Random Number Generator
2120: **
2121: ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
2122: ** select random [ROWID | ROWIDs] when inserting new records into a table that
2123: ** already uses the largest possible [ROWID]. The PRNG is also used for
2124: ** the build-in random() and randomblob() SQL functions. This interface allows
2125: ** applications to access the same PRNG for other purposes.
2126: **
2127: ** ^A call to this routine stores N bytes of randomness into buffer P.
2128: **
2129: ** ^The first time this routine is invoked (either internally or by
2130: ** the application) the PRNG is seeded using randomness obtained
2131: ** from the xRandomness method of the default [sqlite3_vfs] object.
2132: ** ^On all subsequent invocations, the pseudo-randomness is generated
2133: ** internally and without recourse to the [sqlite3_vfs] xRandomness
2134: ** method.
2135: */
2136: SQLITE_API void sqlite3_randomness(int N, void *P);
2137:
2138: /*
2139: ** CAPI3REF: Compile-Time Authorization Callbacks
2140: **
2141: ** ^This routine registers an authorizer callback with a particular
2142: ** [database connection], supplied in the first argument.
2143: ** ^The authorizer callback is invoked as SQL statements are being compiled
2144: ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
2145: ** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various
2146: ** points during the compilation process, as logic is being created
2147: ** to perform various actions, the authorizer callback is invoked to
2148: ** see if those actions are allowed. ^The authorizer callback should
2149: ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
2150: ** specific action but allow the SQL statement to continue to be
2151: ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
2152: ** rejected with an error. ^If the authorizer callback returns
2153: ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
2154: ** then the [sqlite3_prepare_v2()] or equivalent call that triggered
2155: ** the authorizer will fail with an error message.
2156: **
2157: ** When the callback returns [SQLITE_OK], that means the operation
2158: ** requested is ok. ^When the callback returns [SQLITE_DENY], the
2159: ** [sqlite3_prepare_v2()] or equivalent call that triggered the
2160: ** authorizer will fail with an error message explaining that
2161: ** access is denied.
2162: **
2163: ** ^The first parameter to the authorizer callback is a copy of the third
2164: ** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
2165: ** to the callback is an integer [SQLITE_COPY | action code] that specifies
2166: ** the particular action to be authorized. ^The third through sixth parameters
2167: ** to the callback are zero-terminated strings that contain additional
2168: ** details about the action to be authorized.
2169: **
2170: ** ^If the action code is [SQLITE_READ]
2171: ** and the callback returns [SQLITE_IGNORE] then the
2172: ** [prepared statement] statement is constructed to substitute
2173: ** a NULL value in place of the table column that would have
2174: ** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE]
2175: ** return can be used to deny an untrusted user access to individual
2176: ** columns of a table.
2177: ** ^If the action code is [SQLITE_DELETE] and the callback returns
2178: ** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
2179: ** [truncate optimization] is disabled and all rows are deleted individually.
2180: **
2181: ** An authorizer is used when [sqlite3_prepare | preparing]
2182: ** SQL statements from an untrusted source, to ensure that the SQL statements
2183: ** do not try to access data they are not allowed to see, or that they do not
2184: ** try to execute malicious statements that damage the database. For
2185: ** example, an application may allow a user to enter arbitrary
2186: ** SQL queries for evaluation by a database. But the application does
2187: ** not want the user to be able to make arbitrary changes to the
2188: ** database. An authorizer could then be put in place while the
2189: ** user-entered SQL is being [sqlite3_prepare | prepared] that
2190: ** disallows everything except [SELECT] statements.
2191: **
2192: ** Applications that need to process SQL from untrusted sources
2193: ** might also consider lowering resource limits using [sqlite3_limit()]
2194: ** and limiting database size using the [max_page_count] [PRAGMA]
2195: ** in addition to using an authorizer.
2196: **
2197: ** ^(Only a single authorizer can be in place on a database connection
2198: ** at a time. Each call to sqlite3_set_authorizer overrides the
2199: ** previous call.)^ ^Disable the authorizer by installing a NULL callback.
2200: ** The authorizer is disabled by default.
2201: **
2202: ** The authorizer callback must not do anything that will modify
2203: ** the database connection that invoked the authorizer callback.
2204: ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2205: ** database connections for the meaning of "modify" in this paragraph.
2206: **
2207: ** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
2208: ** statement might be re-prepared during [sqlite3_step()] due to a
2209: ** schema change. Hence, the application should ensure that the
2210: ** correct authorizer callback remains in place during the [sqlite3_step()].
2211: **
2212: ** ^Note that the authorizer callback is invoked only during
2213: ** [sqlite3_prepare()] or its variants. Authorization is not
2214: ** performed during statement evaluation in [sqlite3_step()], unless
2215: ** as stated in the previous paragraph, sqlite3_step() invokes
2216: ** sqlite3_prepare_v2() to reprepare a statement after a schema change.
2217: */
2218: SQLITE_API int sqlite3_set_authorizer(
2219: sqlite3*,
2220: int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
2221: void *pUserData
2222: );
2223:
2224: /*
2225: ** CAPI3REF: Authorizer Return Codes
2226: **
2227: ** The [sqlite3_set_authorizer | authorizer callback function] must
2228: ** return either [SQLITE_OK] or one of these two constants in order
2229: ** to signal SQLite whether or not the action is permitted. See the
2230: ** [sqlite3_set_authorizer | authorizer documentation] for additional
2231: ** information.
2232: **
2233: ** Note that SQLITE_IGNORE is also used as a [SQLITE_ROLLBACK | return code]
2234: ** from the [sqlite3_vtab_on_conflict()] interface.
2235: */
2236: #define SQLITE_DENY 1 /* Abort the SQL statement with an error */
2237: #define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */
2238:
2239: /*
2240: ** CAPI3REF: Authorizer Action Codes
2241: **
2242: ** The [sqlite3_set_authorizer()] interface registers a callback function
2243: ** that is invoked to authorize certain SQL statement actions. The
2244: ** second parameter to the callback is an integer code that specifies
2245: ** what action is being authorized. These are the integer action codes that
2246: ** the authorizer callback may be passed.
2247: **
2248: ** These action code values signify what kind of operation is to be
2249: ** authorized. The 3rd and 4th parameters to the authorization
2250: ** callback function will be parameters or NULL depending on which of these
2251: ** codes is used as the second parameter. ^(The 5th parameter to the
2252: ** authorizer callback is the name of the database ("main", "temp",
2253: ** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback
2254: ** is the name of the inner-most trigger or view that is responsible for
2255: ** the access attempt or NULL if this access attempt is directly from
2256: ** top-level SQL code.
2257: */
2258: /******************************************* 3rd ************ 4th ***********/
2259: #define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */
2260: #define SQLITE_CREATE_TABLE 2 /* Table Name NULL */
2261: #define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */
2262: #define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */
2263: #define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */
2264: #define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */
2265: #define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */
2266: #define SQLITE_CREATE_VIEW 8 /* View Name NULL */
2267: #define SQLITE_DELETE 9 /* Table Name NULL */
2268: #define SQLITE_DROP_INDEX 10 /* Index Name Table Name */
2269: #define SQLITE_DROP_TABLE 11 /* Table Name NULL */
2270: #define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */
2271: #define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */
2272: #define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */
2273: #define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */
2274: #define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */
2275: #define SQLITE_DROP_VIEW 17 /* View Name NULL */
2276: #define SQLITE_INSERT 18 /* Table Name NULL */
2277: #define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */
2278: #define SQLITE_READ 20 /* Table Name Column Name */
2279: #define SQLITE_SELECT 21 /* NULL NULL */
2280: #define SQLITE_TRANSACTION 22 /* Operation NULL */
2281: #define SQLITE_UPDATE 23 /* Table Name Column Name */
2282: #define SQLITE_ATTACH 24 /* Filename NULL */
2283: #define SQLITE_DETACH 25 /* Database Name NULL */
2284: #define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */
2285: #define SQLITE_REINDEX 27 /* Index Name NULL */
2286: #define SQLITE_ANALYZE 28 /* Table Name NULL */
2287: #define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */
2288: #define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */
2289: #define SQLITE_FUNCTION 31 /* NULL Function Name */
2290: #define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */
2291: #define SQLITE_COPY 0 /* No longer used */
2292:
2293: /*
2294: ** CAPI3REF: Tracing And Profiling Functions
2295: **
2296: ** These routines register callback functions that can be used for
2297: ** tracing and profiling the execution of SQL statements.
2298: **
2299: ** ^The callback function registered by sqlite3_trace() is invoked at
2300: ** various times when an SQL statement is being run by [sqlite3_step()].
2301: ** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
2302: ** SQL statement text as the statement first begins executing.
2303: ** ^(Additional sqlite3_trace() callbacks might occur
2304: ** as each triggered subprogram is entered. The callbacks for triggers
2305: ** contain a UTF-8 SQL comment that identifies the trigger.)^
2306: **
2307: ** ^The callback function registered by sqlite3_profile() is invoked
2308: ** as each SQL statement finishes. ^The profile callback contains
2309: ** the original statement text and an estimate of wall-clock time
2310: ** of how long that statement took to run. ^The profile callback
2311: ** time is in units of nanoseconds, however the current implementation
2312: ** is only capable of millisecond resolution so the six least significant
2313: ** digits in the time are meaningless. Future versions of SQLite
2314: ** might provide greater resolution on the profiler callback. The
2315: ** sqlite3_profile() function is considered experimental and is
2316: ** subject to change in future versions of SQLite.
2317: */
2318: SQLITE_API void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*);
2319: SQLITE_API SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*,
2320: void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
2321:
2322: /*
2323: ** CAPI3REF: Query Progress Callbacks
2324: **
2325: ** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
2326: ** function X to be invoked periodically during long running calls to
2327: ** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for
2328: ** database connection D. An example use for this
2329: ** interface is to keep a GUI updated during a large query.
2330: **
2331: ** ^The parameter P is passed through as the only parameter to the
2332: ** callback function X. ^The parameter N is the number of
2333: ** [virtual machine instructions] that are evaluated between successive
2334: ** invocations of the callback X.
2335: **
2336: ** ^Only a single progress handler may be defined at one time per
2337: ** [database connection]; setting a new progress handler cancels the
2338: ** old one. ^Setting parameter X to NULL disables the progress handler.
2339: ** ^The progress handler is also disabled by setting N to a value less
2340: ** than 1.
2341: **
2342: ** ^If the progress callback returns non-zero, the operation is
2343: ** interrupted. This feature can be used to implement a
2344: ** "Cancel" button on a GUI progress dialog box.
2345: **
2346: ** The progress handler callback must not do anything that will modify
2347: ** the database connection that invoked the progress handler.
2348: ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2349: ** database connections for the meaning of "modify" in this paragraph.
2350: **
2351: */
2352: SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
2353:
2354: /*
2355: ** CAPI3REF: Opening A New Database Connection
2356: **
2357: ** ^These routines open an SQLite database file as specified by the
2358: ** filename argument. ^The filename argument is interpreted as UTF-8 for
2359: ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
2360: ** order for sqlite3_open16(). ^(A [database connection] handle is usually
2361: ** returned in *ppDb, even if an error occurs. The only exception is that
2362: ** if SQLite is unable to allocate memory to hold the [sqlite3] object,
2363: ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
2364: ** object.)^ ^(If the database is opened (and/or created) successfully, then
2365: ** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The
2366: ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
2367: ** an English language description of the error following a failure of any
2368: ** of the sqlite3_open() routines.
2369: **
2370: ** ^The default encoding for the database will be UTF-8 if
2371: ** sqlite3_open() or sqlite3_open_v2() is called and
2372: ** UTF-16 in the native byte order if sqlite3_open16() is used.
2373: **
2374: ** Whether or not an error occurs when it is opened, resources
2375: ** associated with the [database connection] handle should be released by
2376: ** passing it to [sqlite3_close()] when it is no longer required.
2377: **
2378: ** The sqlite3_open_v2() interface works like sqlite3_open()
2379: ** except that it accepts two additional parameters for additional control
2380: ** over the new database connection. ^(The flags parameter to
2381: ** sqlite3_open_v2() can take one of
2382: ** the following three values, optionally combined with the
2383: ** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE],
2384: ** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^
2385: **
2386: ** <dl>
2387: ** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
2388: ** <dd>The database is opened in read-only mode. If the database does not
2389: ** already exist, an error is returned.</dd>)^
2390: **
2391: ** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
2392: ** <dd>The database is opened for reading and writing if possible, or reading
2393: ** only if the file is write protected by the operating system. In either
2394: ** case the database must already exist, otherwise an error is returned.</dd>)^
2395: **
2396: ** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
2397: ** <dd>The database is opened for reading and writing, and is created if
2398: ** it does not already exist. This is the behavior that is always used for
2399: ** sqlite3_open() and sqlite3_open16().</dd>)^
2400: ** </dl>
2401: **
2402: ** If the 3rd parameter to sqlite3_open_v2() is not one of the
2403: ** combinations shown above optionally combined with other
2404: ** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits]
2405: ** then the behavior is undefined.
2406: **
2407: ** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection
2408: ** opens in the multi-thread [threading mode] as long as the single-thread
2409: ** mode has not been set at compile-time or start-time. ^If the
2410: ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens
2411: ** in the serialized [threading mode] unless single-thread was
2412: ** previously selected at compile-time or start-time.
2413: ** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be
2414: ** eligible to use [shared cache mode], regardless of whether or not shared
2415: ** cache is enabled using [sqlite3_enable_shared_cache()]. ^The
2416: ** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not
2417: ** participate in [shared cache mode] even if it is enabled.
2418: **
2419: ** ^The fourth parameter to sqlite3_open_v2() is the name of the
2420: ** [sqlite3_vfs] object that defines the operating system interface that
2421: ** the new database connection should use. ^If the fourth parameter is
2422: ** a NULL pointer then the default [sqlite3_vfs] object is used.
2423: **
2424: ** ^If the filename is ":memory:", then a private, temporary in-memory database
2425: ** is created for the connection. ^This in-memory database will vanish when
2426: ** the database connection is closed. Future versions of SQLite might
2427: ** make use of additional special filenames that begin with the ":" character.
2428: ** It is recommended that when a database filename actually does begin with
2429: ** a ":" character you should prefix the filename with a pathname such as
2430: ** "./" to avoid ambiguity.
2431: **
2432: ** ^If the filename is an empty string, then a private, temporary
2433: ** on-disk database will be created. ^This private database will be
2434: ** automatically deleted as soon as the database connection is closed.
2435: **
2436: ** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
2437: **
2438: ** ^If [URI filename] interpretation is enabled, and the filename argument
2439: ** begins with "file:", then the filename is interpreted as a URI. ^URI
2440: ** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
2441: ** set in the fourth argument to sqlite3_open_v2(), or if it has
2442: ** been enabled globally using the [SQLITE_CONFIG_URI] option with the
2443: ** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
2444: ** As of SQLite version 3.7.7, URI filename interpretation is turned off
2445: ** by default, but future releases of SQLite might enable URI filename
2446: ** interpretation by default. See "[URI filenames]" for additional
2447: ** information.
2448: **
2449: ** URI filenames are parsed according to RFC 3986. ^If the URI contains an
2450: ** authority, then it must be either an empty string or the string
2451: ** "localhost". ^If the authority is not an empty string or "localhost", an
2452: ** error is returned to the caller. ^The fragment component of a URI, if
2453: ** present, is ignored.
2454: **
2455: ** ^SQLite uses the path component of the URI as the name of the disk file
2456: ** which contains the database. ^If the path begins with a '/' character,
2457: ** then it is interpreted as an absolute path. ^If the path does not begin
2458: ** with a '/' (meaning that the authority section is omitted from the URI)
2459: ** then the path is interpreted as a relative path.
2460: ** ^On windows, the first component of an absolute path
2461: ** is a drive specification (e.g. "C:").
2462: **
2463: ** [[core URI query parameters]]
2464: ** The query component of a URI may contain parameters that are interpreted
2465: ** either by SQLite itself, or by a [VFS | custom VFS implementation].
2466: ** SQLite interprets the following three query parameters:
2467: **
2468: ** <ul>
2469: ** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
2470: ** a VFS object that provides the operating system interface that should
2471: ** be used to access the database file on disk. ^If this option is set to
2472: ** an empty string the default VFS object is used. ^Specifying an unknown
2473: ** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
2474: ** present, then the VFS specified by the option takes precedence over
2475: ** the value passed as the fourth parameter to sqlite3_open_v2().
2476: **
2477: ** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw" or
2478: ** "rwc". Attempting to set it to any other value is an error)^.
2479: ** ^If "ro" is specified, then the database is opened for read-only
2480: ** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the
2481: ** third argument to sqlite3_prepare_v2(). ^If the mode option is set to
2482: ** "rw", then the database is opened for read-write (but not create)
2483: ** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had
2484: ** been set. ^Value "rwc" is equivalent to setting both
2485: ** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If sqlite3_open_v2() is
2486: ** used, it is an error to specify a value for the mode parameter that is
2487: ** less restrictive than that specified by the flags passed as the third
2488: ** parameter.
2489: **
2490: ** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
2491: ** "private". ^Setting it to "shared" is equivalent to setting the
2492: ** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
2493: ** sqlite3_open_v2(). ^Setting the cache parameter to "private" is
2494: ** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
2495: ** ^If sqlite3_open_v2() is used and the "cache" parameter is present in
2496: ** a URI filename, its value overrides any behaviour requested by setting
2497: ** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.
2498: ** </ul>
2499: **
2500: ** ^Specifying an unknown parameter in the query component of a URI is not an
2501: ** error. Future versions of SQLite might understand additional query
2502: ** parameters. See "[query parameters with special meaning to SQLite]" for
2503: ** additional information.
2504: **
2505: ** [[URI filename examples]] <h3>URI filename examples</h3>
2506: **
2507: ** <table border="1" align=center cellpadding=5>
2508: ** <tr><th> URI filenames <th> Results
2509: ** <tr><td> file:data.db <td>
2510: ** Open the file "data.db" in the current directory.
2511: ** <tr><td> file:/home/fred/data.db<br>
2512: ** file:///home/fred/data.db <br>
2513: ** file://localhost/home/fred/data.db <br> <td>
2514: ** Open the database file "/home/fred/data.db".
2515: ** <tr><td> file://darkstar/home/fred/data.db <td>
2516: ** An error. "darkstar" is not a recognized authority.
2517: ** <tr><td style="white-space:nowrap">
2518: ** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
2519: ** <td> Windows only: Open the file "data.db" on fred's desktop on drive
2520: ** C:. Note that the %20 escaping in this example is not strictly
2521: ** necessary - space characters can be used literally
2522: ** in URI filenames.
2523: ** <tr><td> file:data.db?mode=ro&cache=private <td>
2524: ** Open file "data.db" in the current directory for read-only access.
2525: ** Regardless of whether or not shared-cache mode is enabled by
2526: ** default, use a private cache.
2527: ** <tr><td> file:/home/fred/data.db?vfs=unix-nolock <td>
2528: ** Open file "/home/fred/data.db". Use the special VFS "unix-nolock".
2529: ** <tr><td> file:data.db?mode=readonly <td>
2530: ** An error. "readonly" is not a valid option for the "mode" parameter.
2531: ** </table>
2532: **
2533: ** ^URI hexadecimal escape sequences (%HH) are supported within the path and
2534: ** query components of a URI. A hexadecimal escape sequence consists of a
2535: ** percent sign - "%" - followed by exactly two hexadecimal digits
2536: ** specifying an octet value. ^Before the path or query components of a
2537: ** URI filename are interpreted, they are encoded using UTF-8 and all
2538: ** hexadecimal escape sequences replaced by a single byte containing the
2539: ** corresponding octet. If this process generates an invalid UTF-8 encoding,
2540: ** the results are undefined.
2541: **
2542: ** <b>Note to Windows users:</b> The encoding used for the filename argument
2543: ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
2544: ** codepage is currently defined. Filenames containing international
2545: ** characters must be converted to UTF-8 prior to passing them into
2546: ** sqlite3_open() or sqlite3_open_v2().
2547: */
2548: SQLITE_API int sqlite3_open(
2549: const char *filename, /* Database filename (UTF-8) */
2550: sqlite3 **ppDb /* OUT: SQLite db handle */
2551: );
2552: SQLITE_API int sqlite3_open16(
2553: const void *filename, /* Database filename (UTF-16) */
2554: sqlite3 **ppDb /* OUT: SQLite db handle */
2555: );
2556: SQLITE_API int sqlite3_open_v2(
2557: const char *filename, /* Database filename (UTF-8) */
2558: sqlite3 **ppDb, /* OUT: SQLite db handle */
2559: int flags, /* Flags */
2560: const char *zVfs /* Name of VFS module to use */
2561: );
2562:
2563: /*
2564: ** CAPI3REF: Obtain Values For URI Parameters
2565: **
2566: ** This is a utility routine, useful to VFS implementations, that checks
2567: ** to see if a database file was a URI that contained a specific query
2568: ** parameter, and if so obtains the value of the query parameter.
2569: **
2570: ** The zFilename argument is the filename pointer passed into the xOpen()
2571: ** method of a VFS implementation. The zParam argument is the name of the
2572: ** query parameter we seek. This routine returns the value of the zParam
2573: ** parameter if it exists. If the parameter does not exist, this routine
2574: ** returns a NULL pointer.
2575: **
2576: ** If the zFilename argument to this function is not a pointer that SQLite
2577: ** passed into the xOpen VFS method, then the behavior of this routine
2578: ** is undefined and probably undesirable.
2579: */
2580: SQLITE_API const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam);
2581:
2582:
2583: /*
2584: ** CAPI3REF: Error Codes And Messages
2585: **
2586: ** ^The sqlite3_errcode() interface returns the numeric [result code] or
2587: ** [extended result code] for the most recent failed sqlite3_* API call
2588: ** associated with a [database connection]. If a prior API call failed
2589: ** but the most recent API call succeeded, the return value from
2590: ** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode()
2591: ** interface is the same except that it always returns the
2592: ** [extended result code] even when extended result codes are
2593: ** disabled.
2594: **
2595: ** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
2596: ** text that describes the error, as either UTF-8 or UTF-16 respectively.
2597: ** ^(Memory to hold the error message string is managed internally.
2598: ** The application does not need to worry about freeing the result.
2599: ** However, the error string might be overwritten or deallocated by
2600: ** subsequent calls to other SQLite interface functions.)^
2601: **
2602: ** When the serialized [threading mode] is in use, it might be the
2603: ** case that a second error occurs on a separate thread in between
2604: ** the time of the first error and the call to these interfaces.
2605: ** When that happens, the second error will be reported since these
2606: ** interfaces always report the most recent result. To avoid
2607: ** this, each thread can obtain exclusive use of the [database connection] D
2608: ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
2609: ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
2610: ** all calls to the interfaces listed here are completed.
2611: **
2612: ** If an interface fails with SQLITE_MISUSE, that means the interface
2613: ** was invoked incorrectly by the application. In that case, the
2614: ** error code and message may or may not be set.
2615: */
2616: SQLITE_API int sqlite3_errcode(sqlite3 *db);
2617: SQLITE_API int sqlite3_extended_errcode(sqlite3 *db);
2618: SQLITE_API const char *sqlite3_errmsg(sqlite3*);
2619: SQLITE_API const void *sqlite3_errmsg16(sqlite3*);
2620:
2621: /*
2622: ** CAPI3REF: SQL Statement Object
2623: ** KEYWORDS: {prepared statement} {prepared statements}
2624: **
2625: ** An instance of this object represents a single SQL statement.
2626: ** This object is variously known as a "prepared statement" or a
2627: ** "compiled SQL statement" or simply as a "statement".
2628: **
2629: ** The life of a statement object goes something like this:
2630: **
2631: ** <ol>
2632: ** <li> Create the object using [sqlite3_prepare_v2()] or a related
2633: ** function.
2634: ** <li> Bind values to [host parameters] using the sqlite3_bind_*()
2635: ** interfaces.
2636: ** <li> Run the SQL by calling [sqlite3_step()] one or more times.
2637: ** <li> Reset the statement using [sqlite3_reset()] then go back
2638: ** to step 2. Do this zero or more times.
2639: ** <li> Destroy the object using [sqlite3_finalize()].
2640: ** </ol>
2641: **
2642: ** Refer to documentation on individual methods above for additional
2643: ** information.
2644: */
2645: typedef struct sqlite3_stmt sqlite3_stmt;
2646:
2647: /*
2648: ** CAPI3REF: Run-time Limits
2649: **
2650: ** ^(This interface allows the size of various constructs to be limited
2651: ** on a connection by connection basis. The first parameter is the
2652: ** [database connection] whose limit is to be set or queried. The
2653: ** second parameter is one of the [limit categories] that define a
2654: ** class of constructs to be size limited. The third parameter is the
2655: ** new limit for that construct.)^
2656: **
2657: ** ^If the new limit is a negative number, the limit is unchanged.
2658: ** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
2659: ** [limits | hard upper bound]
2660: ** set at compile-time by a C preprocessor macro called
2661: ** [limits | SQLITE_MAX_<i>NAME</i>].
2662: ** (The "_LIMIT_" in the name is changed to "_MAX_".))^
2663: ** ^Attempts to increase a limit above its hard upper bound are
2664: ** silently truncated to the hard upper bound.
2665: **
2666: ** ^Regardless of whether or not the limit was changed, the
2667: ** [sqlite3_limit()] interface returns the prior value of the limit.
2668: ** ^Hence, to find the current value of a limit without changing it,
2669: ** simply invoke this interface with the third parameter set to -1.
2670: **
2671: ** Run-time limits are intended for use in applications that manage
2672: ** both their own internal database and also databases that are controlled
2673: ** by untrusted external sources. An example application might be a
2674: ** web browser that has its own databases for storing history and
2675: ** separate databases controlled by JavaScript applications downloaded
2676: ** off the Internet. The internal databases can be given the
2677: ** large, default limits. Databases managed by external sources can
2678: ** be given much smaller limits designed to prevent a denial of service
2679: ** attack. Developers might also want to use the [sqlite3_set_authorizer()]
2680: ** interface to further control untrusted SQL. The size of the database
2681: ** created by an untrusted script can be contained using the
2682: ** [max_page_count] [PRAGMA].
2683: **
2684: ** New run-time limit categories may be added in future releases.
2685: */
2686: SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal);
2687:
2688: /*
2689: ** CAPI3REF: Run-Time Limit Categories
2690: ** KEYWORDS: {limit category} {*limit categories}
2691: **
2692: ** These constants define various performance limits
2693: ** that can be lowered at run-time using [sqlite3_limit()].
2694: ** The synopsis of the meanings of the various limits is shown below.
2695: ** Additional information is available at [limits | Limits in SQLite].
2696: **
2697: ** <dl>
2698: ** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt>
2699: ** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
2700: **
2701: ** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
2702: ** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
2703: **
2704: ** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt>
2705: ** <dd>The maximum number of columns in a table definition or in the
2706: ** result set of a [SELECT] or the maximum number of columns in an index
2707: ** or in an ORDER BY or GROUP BY clause.</dd>)^
2708: **
2709: ** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
2710: ** <dd>The maximum depth of the parse tree on any expression.</dd>)^
2711: **
2712: ** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
2713: ** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
2714: **
2715: ** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
2716: ** <dd>The maximum number of instructions in a virtual machine program
2717: ** used to implement an SQL statement. This limit is not currently
2718: ** enforced, though that might be added in some future release of
2719: ** SQLite.</dd>)^
2720: **
2721: ** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
2722: ** <dd>The maximum number of arguments on a function.</dd>)^
2723: **
2724: ** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
2725: ** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
2726: **
2727: ** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]]
2728: ** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
2729: ** <dd>The maximum length of the pattern argument to the [LIKE] or
2730: ** [GLOB] operators.</dd>)^
2731: **
2732: ** [[SQLITE_LIMIT_VARIABLE_NUMBER]]
2733: ** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
2734: ** <dd>The maximum index number of any [parameter] in an SQL statement.)^
2735: **
2736: ** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
2737: ** <dd>The maximum depth of recursion for triggers.</dd>)^
2738: ** </dl>
2739: */
2740: #define SQLITE_LIMIT_LENGTH 0
2741: #define SQLITE_LIMIT_SQL_LENGTH 1
2742: #define SQLITE_LIMIT_COLUMN 2
2743: #define SQLITE_LIMIT_EXPR_DEPTH 3
2744: #define SQLITE_LIMIT_COMPOUND_SELECT 4
2745: #define SQLITE_LIMIT_VDBE_OP 5
2746: #define SQLITE_LIMIT_FUNCTION_ARG 6
2747: #define SQLITE_LIMIT_ATTACHED 7
2748: #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8
2749: #define SQLITE_LIMIT_VARIABLE_NUMBER 9
2750: #define SQLITE_LIMIT_TRIGGER_DEPTH 10
2751:
2752: /*
2753: ** CAPI3REF: Compiling An SQL Statement
2754: ** KEYWORDS: {SQL statement compiler}
2755: **
2756: ** To execute an SQL query, it must first be compiled into a byte-code
2757: ** program using one of these routines.
2758: **
2759: ** The first argument, "db", is a [database connection] obtained from a
2760: ** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
2761: ** [sqlite3_open16()]. The database connection must not have been closed.
2762: **
2763: ** The second argument, "zSql", is the statement to be compiled, encoded
2764: ** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2()
2765: ** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2()
2766: ** use UTF-16.
2767: **
2768: ** ^If the nByte argument is less than zero, then zSql is read up to the
2769: ** first zero terminator. ^If nByte is non-negative, then it is the maximum
2770: ** number of bytes read from zSql. ^When nByte is non-negative, the
2771: ** zSql string ends at either the first '\000' or '\u0000' character or
2772: ** the nByte-th byte, whichever comes first. If the caller knows
2773: ** that the supplied string is nul-terminated, then there is a small
2774: ** performance advantage to be gained by passing an nByte parameter that
2775: ** is equal to the number of bytes in the input string <i>including</i>
2776: ** the nul-terminator bytes.
2777: **
2778: ** ^If pzTail is not NULL then *pzTail is made to point to the first byte
2779: ** past the end of the first SQL statement in zSql. These routines only
2780: ** compile the first statement in zSql, so *pzTail is left pointing to
2781: ** what remains uncompiled.
2782: **
2783: ** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
2784: ** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set
2785: ** to NULL. ^If the input text contains no SQL (if the input is an empty
2786: ** string or a comment) then *ppStmt is set to NULL.
2787: ** The calling procedure is responsible for deleting the compiled
2788: ** SQL statement using [sqlite3_finalize()] after it has finished with it.
2789: ** ppStmt may not be NULL.
2790: **
2791: ** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
2792: ** otherwise an [error code] is returned.
2793: **
2794: ** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are
2795: ** recommended for all new programs. The two older interfaces are retained
2796: ** for backwards compatibility, but their use is discouraged.
2797: ** ^In the "v2" interfaces, the prepared statement
2798: ** that is returned (the [sqlite3_stmt] object) contains a copy of the
2799: ** original SQL text. This causes the [sqlite3_step()] interface to
2800: ** behave differently in three ways:
2801: **
2802: ** <ol>
2803: ** <li>
2804: ** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
2805: ** always used to do, [sqlite3_step()] will automatically recompile the SQL
2806: ** statement and try to run it again.
2807: ** </li>
2808: **
2809: ** <li>
2810: ** ^When an error occurs, [sqlite3_step()] will return one of the detailed
2811: ** [error codes] or [extended error codes]. ^The legacy behavior was that
2812: ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
2813: ** and the application would have to make a second call to [sqlite3_reset()]
2814: ** in order to find the underlying cause of the problem. With the "v2" prepare
2815: ** interfaces, the underlying reason for the error is returned immediately.
2816: ** </li>
2817: **
2818: ** <li>
2819: ** ^If the specific value bound to [parameter | host parameter] in the
2820: ** WHERE clause might influence the choice of query plan for a statement,
2821: ** then the statement will be automatically recompiled, as if there had been
2822: ** a schema change, on the first [sqlite3_step()] call following any change
2823: ** to the [sqlite3_bind_text | bindings] of that [parameter].
2824: ** ^The specific value of WHERE-clause [parameter] might influence the
2825: ** choice of query plan if the parameter is the left-hand side of a [LIKE]
2826: ** or [GLOB] operator or if the parameter is compared to an indexed column
2827: ** and the [SQLITE_ENABLE_STAT2] compile-time option is enabled.
2828: ** the
2829: ** </li>
2830: ** </ol>
2831: */
2832: SQLITE_API int sqlite3_prepare(
2833: sqlite3 *db, /* Database handle */
2834: const char *zSql, /* SQL statement, UTF-8 encoded */
2835: int nByte, /* Maximum length of zSql in bytes. */
2836: sqlite3_stmt **ppStmt, /* OUT: Statement handle */
2837: const char **pzTail /* OUT: Pointer to unused portion of zSql */
2838: );
2839: SQLITE_API int sqlite3_prepare_v2(
2840: sqlite3 *db, /* Database handle */
2841: const char *zSql, /* SQL statement, UTF-8 encoded */
2842: int nByte, /* Maximum length of zSql in bytes. */
2843: sqlite3_stmt **ppStmt, /* OUT: Statement handle */
2844: const char **pzTail /* OUT: Pointer to unused portion of zSql */
2845: );
2846: SQLITE_API int sqlite3_prepare16(
2847: sqlite3 *db, /* Database handle */
2848: const void *zSql, /* SQL statement, UTF-16 encoded */
2849: int nByte, /* Maximum length of zSql in bytes. */
2850: sqlite3_stmt **ppStmt, /* OUT: Statement handle */
2851: const void **pzTail /* OUT: Pointer to unused portion of zSql */
2852: );
2853: SQLITE_API int sqlite3_prepare16_v2(
2854: sqlite3 *db, /* Database handle */
2855: const void *zSql, /* SQL statement, UTF-16 encoded */
2856: int nByte, /* Maximum length of zSql in bytes. */
2857: sqlite3_stmt **ppStmt, /* OUT: Statement handle */
2858: const void **pzTail /* OUT: Pointer to unused portion of zSql */
2859: );
2860:
2861: /*
2862: ** CAPI3REF: Retrieving Statement SQL
2863: **
2864: ** ^This interface can be used to retrieve a saved copy of the original
2865: ** SQL text used to create a [prepared statement] if that statement was
2866: ** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()].
2867: */
2868: SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt);
2869:
2870: /*
2871: ** CAPI3REF: Determine If An SQL Statement Writes The Database
2872: **
2873: ** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
2874: ** and only if the [prepared statement] X makes no direct changes to
2875: ** the content of the database file.
2876: **
2877: ** Note that [application-defined SQL functions] or
2878: ** [virtual tables] might change the database indirectly as a side effect.
2879: ** ^(For example, if an application defines a function "eval()" that
2880: ** calls [sqlite3_exec()], then the following SQL statement would
2881: ** change the database file through side-effects:
2882: **
2883: ** <blockquote><pre>
2884: ** SELECT eval('DELETE FROM t1') FROM t2;
2885: ** </pre></blockquote>
2886: **
2887: ** But because the [SELECT] statement does not change the database file
2888: ** directly, sqlite3_stmt_readonly() would still return true.)^
2889: **
2890: ** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
2891: ** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
2892: ** since the statements themselves do not actually modify the database but
2893: ** rather they control the timing of when other statements modify the
2894: ** database. ^The [ATTACH] and [DETACH] statements also cause
2895: ** sqlite3_stmt_readonly() to return true since, while those statements
2896: ** change the configuration of a database connection, they do not make
2897: ** changes to the content of the database files on disk.
2898: */
2899: SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
2900:
2901: /*
2902: ** CAPI3REF: Dynamically Typed Value Object
2903: ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
2904: **
2905: ** SQLite uses the sqlite3_value object to represent all values
2906: ** that can be stored in a database table. SQLite uses dynamic typing
2907: ** for the values it stores. ^Values stored in sqlite3_value objects
2908: ** can be integers, floating point values, strings, BLOBs, or NULL.
2909: **
2910: ** An sqlite3_value object may be either "protected" or "unprotected".
2911: ** Some interfaces require a protected sqlite3_value. Other interfaces
2912: ** will accept either a protected or an unprotected sqlite3_value.
2913: ** Every interface that accepts sqlite3_value arguments specifies
2914: ** whether or not it requires a protected sqlite3_value.
2915: **
2916: ** The terms "protected" and "unprotected" refer to whether or not
2917: ** a mutex is held. An internal mutex is held for a protected
2918: ** sqlite3_value object but no mutex is held for an unprotected
2919: ** sqlite3_value object. If SQLite is compiled to be single-threaded
2920: ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
2921: ** or if SQLite is run in one of reduced mutex modes
2922: ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
2923: ** then there is no distinction between protected and unprotected
2924: ** sqlite3_value objects and they can be used interchangeably. However,
2925: ** for maximum code portability it is recommended that applications
2926: ** still make the distinction between protected and unprotected
2927: ** sqlite3_value objects even when not strictly required.
2928: **
2929: ** ^The sqlite3_value objects that are passed as parameters into the
2930: ** implementation of [application-defined SQL functions] are protected.
2931: ** ^The sqlite3_value object returned by
2932: ** [sqlite3_column_value()] is unprotected.
2933: ** Unprotected sqlite3_value objects may only be used with
2934: ** [sqlite3_result_value()] and [sqlite3_bind_value()].
2935: ** The [sqlite3_value_blob | sqlite3_value_type()] family of
2936: ** interfaces require protected sqlite3_value objects.
2937: */
2938: typedef struct Mem sqlite3_value;
2939:
2940: /*
2941: ** CAPI3REF: SQL Function Context Object
2942: **
2943: ** The context in which an SQL function executes is stored in an
2944: ** sqlite3_context object. ^A pointer to an sqlite3_context object
2945: ** is always first parameter to [application-defined SQL functions].
2946: ** The application-defined SQL function implementation will pass this
2947: ** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
2948: ** [sqlite3_aggregate_context()], [sqlite3_user_data()],
2949: ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
2950: ** and/or [sqlite3_set_auxdata()].
2951: */
2952: typedef struct sqlite3_context sqlite3_context;
2953:
2954: /*
2955: ** CAPI3REF: Binding Values To Prepared Statements
2956: ** KEYWORDS: {host parameter} {host parameters} {host parameter name}
2957: ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
2958: **
2959: ** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
2960: ** literals may be replaced by a [parameter] that matches one of following
2961: ** templates:
2962: **
2963: ** <ul>
2964: ** <li> ?
2965: ** <li> ?NNN
2966: ** <li> :VVV
2967: ** <li> @VVV
2968: ** <li> $VVV
2969: ** </ul>
2970: **
2971: ** In the templates above, NNN represents an integer literal,
2972: ** and VVV represents an alphanumeric identifier.)^ ^The values of these
2973: ** parameters (also called "host parameter names" or "SQL parameters")
2974: ** can be set using the sqlite3_bind_*() routines defined here.
2975: **
2976: ** ^The first argument to the sqlite3_bind_*() routines is always
2977: ** a pointer to the [sqlite3_stmt] object returned from
2978: ** [sqlite3_prepare_v2()] or its variants.
2979: **
2980: ** ^The second argument is the index of the SQL parameter to be set.
2981: ** ^The leftmost SQL parameter has an index of 1. ^When the same named
2982: ** SQL parameter is used more than once, second and subsequent
2983: ** occurrences have the same index as the first occurrence.
2984: ** ^The index for named parameters can be looked up using the
2985: ** [sqlite3_bind_parameter_index()] API if desired. ^The index
2986: ** for "?NNN" parameters is the value of NNN.
2987: ** ^The NNN value must be between 1 and the [sqlite3_limit()]
2988: ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999).
2989: **
2990: ** ^The third argument is the value to bind to the parameter.
2991: **
2992: ** ^(In those routines that have a fourth argument, its value is the
2993: ** number of bytes in the parameter. To be clear: the value is the
2994: ** number of <u>bytes</u> in the value, not the number of characters.)^
2995: ** ^If the fourth parameter is negative, the length of the string is
2996: ** the number of bytes up to the first zero terminator.
2997: **
2998: ** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and
2999: ** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or
3000: ** string after SQLite has finished with it. ^The destructor is called
3001: ** to dispose of the BLOB or string even if the call to sqlite3_bind_blob(),
3002: ** sqlite3_bind_text(), or sqlite3_bind_text16() fails.
3003: ** ^If the fifth argument is
3004: ** the special value [SQLITE_STATIC], then SQLite assumes that the
3005: ** information is in static, unmanaged space and does not need to be freed.
3006: ** ^If the fifth argument has the value [SQLITE_TRANSIENT], then
3007: ** SQLite makes its own private copy of the data immediately, before
3008: ** the sqlite3_bind_*() routine returns.
3009: **
3010: ** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
3011: ** is filled with zeroes. ^A zeroblob uses a fixed amount of memory
3012: ** (just an integer to hold its size) while it is being processed.
3013: ** Zeroblobs are intended to serve as placeholders for BLOBs whose
3014: ** content is later written using
3015: ** [sqlite3_blob_open | incremental BLOB I/O] routines.
3016: ** ^A negative value for the zeroblob results in a zero-length BLOB.
3017: **
3018: ** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
3019: ** for the [prepared statement] or with a prepared statement for which
3020: ** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
3021: ** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_()
3022: ** routine is passed a [prepared statement] that has been finalized, the
3023: ** result is undefined and probably harmful.
3024: **
3025: ** ^Bindings are not cleared by the [sqlite3_reset()] routine.
3026: ** ^Unbound parameters are interpreted as NULL.
3027: **
3028: ** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
3029: ** [error code] if anything goes wrong.
3030: ** ^[SQLITE_RANGE] is returned if the parameter
3031: ** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails.
3032: **
3033: ** See also: [sqlite3_bind_parameter_count()],
3034: ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
3035: */
3036: SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
3037: SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double);
3038: SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int);
3039: SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
3040: SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int);
3041: SQLITE_API int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*));
3042: SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
3043: SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
3044: SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
3045:
3046: /*
3047: ** CAPI3REF: Number Of SQL Parameters
3048: **
3049: ** ^This routine can be used to find the number of [SQL parameters]
3050: ** in a [prepared statement]. SQL parameters are tokens of the
3051: ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
3052: ** placeholders for values that are [sqlite3_bind_blob | bound]
3053: ** to the parameters at a later time.
3054: **
3055: ** ^(This routine actually returns the index of the largest (rightmost)
3056: ** parameter. For all forms except ?NNN, this will correspond to the
3057: ** number of unique parameters. If parameters of the ?NNN form are used,
3058: ** there may be gaps in the list.)^
3059: **
3060: ** See also: [sqlite3_bind_blob|sqlite3_bind()],
3061: ** [sqlite3_bind_parameter_name()], and
3062: ** [sqlite3_bind_parameter_index()].
3063: */
3064: SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*);
3065:
3066: /*
3067: ** CAPI3REF: Name Of A Host Parameter
3068: **
3069: ** ^The sqlite3_bind_parameter_name(P,N) interface returns
3070: ** the name of the N-th [SQL parameter] in the [prepared statement] P.
3071: ** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
3072: ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
3073: ** respectively.
3074: ** In other words, the initial ":" or "$" or "@" or "?"
3075: ** is included as part of the name.)^
3076: ** ^Parameters of the form "?" without a following integer have no name
3077: ** and are referred to as "nameless" or "anonymous parameters".
3078: **
3079: ** ^The first host parameter has an index of 1, not 0.
3080: **
3081: ** ^If the value N is out of range or if the N-th parameter is
3082: ** nameless, then NULL is returned. ^The returned string is
3083: ** always in UTF-8 encoding even if the named parameter was
3084: ** originally specified as UTF-16 in [sqlite3_prepare16()] or
3085: ** [sqlite3_prepare16_v2()].
3086: **
3087: ** See also: [sqlite3_bind_blob|sqlite3_bind()],
3088: ** [sqlite3_bind_parameter_count()], and
3089: ** [sqlite3_bind_parameter_index()].
3090: */
3091: SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
3092:
3093: /*
3094: ** CAPI3REF: Index Of A Parameter With A Given Name
3095: **
3096: ** ^Return the index of an SQL parameter given its name. ^The
3097: ** index value returned is suitable for use as the second
3098: ** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero
3099: ** is returned if no matching parameter is found. ^The parameter
3100: ** name must be given in UTF-8 even if the original statement
3101: ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()].
3102: **
3103: ** See also: [sqlite3_bind_blob|sqlite3_bind()],
3104: ** [sqlite3_bind_parameter_count()], and
3105: ** [sqlite3_bind_parameter_index()].
3106: */
3107: SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
3108:
3109: /*
3110: ** CAPI3REF: Reset All Bindings On A Prepared Statement
3111: **
3112: ** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
3113: ** the [sqlite3_bind_blob | bindings] on a [prepared statement].
3114: ** ^Use this routine to reset all host parameters to NULL.
3115: */
3116: SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*);
3117:
3118: /*
3119: ** CAPI3REF: Number Of Columns In A Result Set
3120: **
3121: ** ^Return the number of columns in the result set returned by the
3122: ** [prepared statement]. ^This routine returns 0 if pStmt is an SQL
3123: ** statement that does not return data (for example an [UPDATE]).
3124: **
3125: ** See also: [sqlite3_data_count()]
3126: */
3127: SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt);
3128:
3129: /*
3130: ** CAPI3REF: Column Names In A Result Set
3131: **
3132: ** ^These routines return the name assigned to a particular column
3133: ** in the result set of a [SELECT] statement. ^The sqlite3_column_name()
3134: ** interface returns a pointer to a zero-terminated UTF-8 string
3135: ** and sqlite3_column_name16() returns a pointer to a zero-terminated
3136: ** UTF-16 string. ^The first parameter is the [prepared statement]
3137: ** that implements the [SELECT] statement. ^The second parameter is the
3138: ** column number. ^The leftmost column is number 0.
3139: **
3140: ** ^The returned string pointer is valid until either the [prepared statement]
3141: ** is destroyed by [sqlite3_finalize()] or until the statement is automatically
3142: ** reprepared by the first call to [sqlite3_step()] for a particular run
3143: ** or until the next call to
3144: ** sqlite3_column_name() or sqlite3_column_name16() on the same column.
3145: **
3146: ** ^If sqlite3_malloc() fails during the processing of either routine
3147: ** (for example during a conversion from UTF-8 to UTF-16) then a
3148: ** NULL pointer is returned.
3149: **
3150: ** ^The name of a result column is the value of the "AS" clause for
3151: ** that column, if there is an AS clause. If there is no AS clause
3152: ** then the name of the column is unspecified and may change from
3153: ** one release of SQLite to the next.
3154: */
3155: SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N);
3156: SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N);
3157:
3158: /*
3159: ** CAPI3REF: Source Of Data In A Query Result
3160: **
3161: ** ^These routines provide a means to determine the database, table, and
3162: ** table column that is the origin of a particular result column in
3163: ** [SELECT] statement.
3164: ** ^The name of the database or table or column can be returned as
3165: ** either a UTF-8 or UTF-16 string. ^The _database_ routines return
3166: ** the database name, the _table_ routines return the table name, and
3167: ** the origin_ routines return the column name.
3168: ** ^The returned string is valid until the [prepared statement] is destroyed
3169: ** using [sqlite3_finalize()] or until the statement is automatically
3170: ** reprepared by the first call to [sqlite3_step()] for a particular run
3171: ** or until the same information is requested
3172: ** again in a different encoding.
3173: **
3174: ** ^The names returned are the original un-aliased names of the
3175: ** database, table, and column.
3176: **
3177: ** ^The first argument to these interfaces is a [prepared statement].
3178: ** ^These functions return information about the Nth result column returned by
3179: ** the statement, where N is the second function argument.
3180: ** ^The left-most column is column 0 for these routines.
3181: **
3182: ** ^If the Nth column returned by the statement is an expression or
3183: ** subquery and is not a column value, then all of these functions return
3184: ** NULL. ^These routine might also return NULL if a memory allocation error
3185: ** occurs. ^Otherwise, they return the name of the attached database, table,
3186: ** or column that query result column was extracted from.
3187: **
3188: ** ^As with all other SQLite APIs, those whose names end with "16" return
3189: ** UTF-16 encoded strings and the other functions return UTF-8.
3190: **
3191: ** ^These APIs are only available if the library was compiled with the
3192: ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
3193: **
3194: ** If two or more threads call one or more of these routines against the same
3195: ** prepared statement and column at the same time then the results are
3196: ** undefined.
3197: **
3198: ** If two or more threads call one or more
3199: ** [sqlite3_column_database_name | column metadata interfaces]
3200: ** for the same [prepared statement] and result column
3201: ** at the same time then the results are undefined.
3202: */
3203: SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int);
3204: SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
3205: SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int);
3206: SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
3207: SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
3208: SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
3209:
3210: /*
3211: ** CAPI3REF: Declared Datatype Of A Query Result
3212: **
3213: ** ^(The first parameter is a [prepared statement].
3214: ** If this statement is a [SELECT] statement and the Nth column of the
3215: ** returned result set of that [SELECT] is a table column (not an
3216: ** expression or subquery) then the declared type of the table
3217: ** column is returned.)^ ^If the Nth column of the result set is an
3218: ** expression or subquery, then a NULL pointer is returned.
3219: ** ^The returned string is always UTF-8 encoded.
3220: **
3221: ** ^(For example, given the database schema:
3222: **
3223: ** CREATE TABLE t1(c1 VARIANT);
3224: **
3225: ** and the following statement to be compiled:
3226: **
3227: ** SELECT c1 + 1, c1 FROM t1;
3228: **
3229: ** this routine would return the string "VARIANT" for the second result
3230: ** column (i==1), and a NULL pointer for the first result column (i==0).)^
3231: **
3232: ** ^SQLite uses dynamic run-time typing. ^So just because a column
3233: ** is declared to contain a particular type does not mean that the
3234: ** data stored in that column is of the declared type. SQLite is
3235: ** strongly typed, but the typing is dynamic not static. ^Type
3236: ** is associated with individual values, not with the containers
3237: ** used to hold those values.
3238: */
3239: SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int);
3240: SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
3241:
3242: /*
3243: ** CAPI3REF: Evaluate An SQL Statement
3244: **
3245: ** After a [prepared statement] has been prepared using either
3246: ** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy
3247: ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
3248: ** must be called one or more times to evaluate the statement.
3249: **
3250: ** The details of the behavior of the sqlite3_step() interface depend
3251: ** on whether the statement was prepared using the newer "v2" interface
3252: ** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy
3253: ** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the
3254: ** new "v2" interface is recommended for new applications but the legacy
3255: ** interface will continue to be supported.
3256: **
3257: ** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
3258: ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
3259: ** ^With the "v2" interface, any of the other [result codes] or
3260: ** [extended result codes] might be returned as well.
3261: **
3262: ** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
3263: ** database locks it needs to do its job. ^If the statement is a [COMMIT]
3264: ** or occurs outside of an explicit transaction, then you can retry the
3265: ** statement. If the statement is not a [COMMIT] and occurs within an
3266: ** explicit transaction then you should rollback the transaction before
3267: ** continuing.
3268: **
3269: ** ^[SQLITE_DONE] means that the statement has finished executing
3270: ** successfully. sqlite3_step() should not be called again on this virtual
3271: ** machine without first calling [sqlite3_reset()] to reset the virtual
3272: ** machine back to its initial state.
3273: **
3274: ** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
3275: ** is returned each time a new row of data is ready for processing by the
3276: ** caller. The values may be accessed using the [column access functions].
3277: ** sqlite3_step() is called again to retrieve the next row of data.
3278: **
3279: ** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
3280: ** violation) has occurred. sqlite3_step() should not be called again on
3281: ** the VM. More information may be found by calling [sqlite3_errmsg()].
3282: ** ^With the legacy interface, a more specific error code (for example,
3283: ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
3284: ** can be obtained by calling [sqlite3_reset()] on the
3285: ** [prepared statement]. ^In the "v2" interface,
3286: ** the more specific error code is returned directly by sqlite3_step().
3287: **
3288: ** [SQLITE_MISUSE] means that the this routine was called inappropriately.
3289: ** Perhaps it was called on a [prepared statement] that has
3290: ** already been [sqlite3_finalize | finalized] or on one that had
3291: ** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could
3292: ** be the case that the same database connection is being used by two or
3293: ** more threads at the same moment in time.
3294: **
3295: ** For all versions of SQLite up to and including 3.6.23.1, a call to
3296: ** [sqlite3_reset()] was required after sqlite3_step() returned anything
3297: ** other than [SQLITE_ROW] before any subsequent invocation of
3298: ** sqlite3_step(). Failure to reset the prepared statement using
3299: ** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
3300: ** sqlite3_step(). But after version 3.6.23.1, sqlite3_step() began
3301: ** calling [sqlite3_reset()] automatically in this circumstance rather
3302: ** than returning [SQLITE_MISUSE]. This is not considered a compatibility
3303: ** break because any application that ever receives an SQLITE_MISUSE error
3304: ** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option
3305: ** can be used to restore the legacy behavior.
3306: **
3307: ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
3308: ** API always returns a generic error code, [SQLITE_ERROR], following any
3309: ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call
3310: ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
3311: ** specific [error codes] that better describes the error.
3312: ** We admit that this is a goofy design. The problem has been fixed
3313: ** with the "v2" interface. If you prepare all of your SQL statements
3314: ** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead
3315: ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
3316: ** then the more specific [error codes] are returned directly
3317: ** by sqlite3_step(). The use of the "v2" interface is recommended.
3318: */
3319: SQLITE_API int sqlite3_step(sqlite3_stmt*);
3320:
3321: /*
3322: ** CAPI3REF: Number of columns in a result set
3323: **
3324: ** ^The sqlite3_data_count(P) interface returns the number of columns in the
3325: ** current row of the result set of [prepared statement] P.
3326: ** ^If prepared statement P does not have results ready to return
3327: ** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of
3328: ** interfaces) then sqlite3_data_count(P) returns 0.
3329: ** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
3330: **
3331: ** See also: [sqlite3_column_count()]
3332: */
3333: SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
3334:
3335: /*
3336: ** CAPI3REF: Fundamental Datatypes
3337: ** KEYWORDS: SQLITE_TEXT
3338: **
3339: ** ^(Every value in SQLite has one of five fundamental datatypes:
3340: **
3341: ** <ul>
3342: ** <li> 64-bit signed integer
3343: ** <li> 64-bit IEEE floating point number
3344: ** <li> string
3345: ** <li> BLOB
3346: ** <li> NULL
3347: ** </ul>)^
3348: **
3349: ** These constants are codes for each of those types.
3350: **
3351: ** Note that the SQLITE_TEXT constant was also used in SQLite version 2
3352: ** for a completely different meaning. Software that links against both
3353: ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
3354: ** SQLITE_TEXT.
3355: */
3356: #define SQLITE_INTEGER 1
3357: #define SQLITE_FLOAT 2
3358: #define SQLITE_BLOB 4
3359: #define SQLITE_NULL 5
3360: #ifdef SQLITE_TEXT
3361: # undef SQLITE_TEXT
3362: #else
3363: # define SQLITE_TEXT 3
3364: #endif
3365: #define SQLITE3_TEXT 3
3366:
3367: /*
3368: ** CAPI3REF: Result Values From A Query
3369: ** KEYWORDS: {column access functions}
3370: **
3371: ** These routines form the "result set" interface.
3372: **
3373: ** ^These routines return information about a single column of the current
3374: ** result row of a query. ^In every case the first argument is a pointer
3375: ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
3376: ** that was returned from [sqlite3_prepare_v2()] or one of its variants)
3377: ** and the second argument is the index of the column for which information
3378: ** should be returned. ^The leftmost column of the result set has the index 0.
3379: ** ^The number of columns in the result can be determined using
3380: ** [sqlite3_column_count()].
3381: **
3382: ** If the SQL statement does not currently point to a valid row, or if the
3383: ** column index is out of range, the result is undefined.
3384: ** These routines may only be called when the most recent call to
3385: ** [sqlite3_step()] has returned [SQLITE_ROW] and neither
3386: ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
3387: ** If any of these routines are called after [sqlite3_reset()] or
3388: ** [sqlite3_finalize()] or after [sqlite3_step()] has returned
3389: ** something other than [SQLITE_ROW], the results are undefined.
3390: ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
3391: ** are called from a different thread while any of these routines
3392: ** are pending, then the results are undefined.
3393: **
3394: ** ^The sqlite3_column_type() routine returns the
3395: ** [SQLITE_INTEGER | datatype code] for the initial data type
3396: ** of the result column. ^The returned value is one of [SQLITE_INTEGER],
3397: ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value
3398: ** returned by sqlite3_column_type() is only meaningful if no type
3399: ** conversions have occurred as described below. After a type conversion,
3400: ** the value returned by sqlite3_column_type() is undefined. Future
3401: ** versions of SQLite may change the behavior of sqlite3_column_type()
3402: ** following a type conversion.
3403: **
3404: ** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
3405: ** routine returns the number of bytes in that BLOB or string.
3406: ** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
3407: ** the string to UTF-8 and then returns the number of bytes.
3408: ** ^If the result is a numeric value then sqlite3_column_bytes() uses
3409: ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
3410: ** the number of bytes in that string.
3411: ** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
3412: **
3413: ** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
3414: ** routine returns the number of bytes in that BLOB or string.
3415: ** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
3416: ** the string to UTF-16 and then returns the number of bytes.
3417: ** ^If the result is a numeric value then sqlite3_column_bytes16() uses
3418: ** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
3419: ** the number of bytes in that string.
3420: ** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
3421: **
3422: ** ^The values returned by [sqlite3_column_bytes()] and
3423: ** [sqlite3_column_bytes16()] do not include the zero terminators at the end
3424: ** of the string. ^For clarity: the values returned by
3425: ** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
3426: ** bytes in the string, not the number of characters.
3427: **
3428: ** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
3429: ** even empty strings, are always zero terminated. ^The return
3430: ** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
3431: **
3432: ** ^The object returned by [sqlite3_column_value()] is an
3433: ** [unprotected sqlite3_value] object. An unprotected sqlite3_value object
3434: ** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()].
3435: ** If the [unprotected sqlite3_value] object returned by
3436: ** [sqlite3_column_value()] is used in any other way, including calls
3437: ** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
3438: ** or [sqlite3_value_bytes()], then the behavior is undefined.
3439: **
3440: ** These routines attempt to convert the value where appropriate. ^For
3441: ** example, if the internal representation is FLOAT and a text result
3442: ** is requested, [sqlite3_snprintf()] is used internally to perform the
3443: ** conversion automatically. ^(The following table details the conversions
3444: ** that are applied:
3445: **
3446: ** <blockquote>
3447: ** <table border="1">
3448: ** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion
3449: **
3450: ** <tr><td> NULL <td> INTEGER <td> Result is 0
3451: ** <tr><td> NULL <td> FLOAT <td> Result is 0.0
3452: ** <tr><td> NULL <td> TEXT <td> Result is NULL pointer
3453: ** <tr><td> NULL <td> BLOB <td> Result is NULL pointer
3454: ** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float
3455: ** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer
3456: ** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT
3457: ** <tr><td> FLOAT <td> INTEGER <td> Convert from float to integer
3458: ** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float
3459: ** <tr><td> FLOAT <td> BLOB <td> Same as FLOAT->TEXT
3460: ** <tr><td> TEXT <td> INTEGER <td> Use atoi()
3461: ** <tr><td> TEXT <td> FLOAT <td> Use atof()
3462: ** <tr><td> TEXT <td> BLOB <td> No change
3463: ** <tr><td> BLOB <td> INTEGER <td> Convert to TEXT then use atoi()
3464: ** <tr><td> BLOB <td> FLOAT <td> Convert to TEXT then use atof()
3465: ** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed
3466: ** </table>
3467: ** </blockquote>)^
3468: **
3469: ** The table above makes reference to standard C library functions atoi()
3470: ** and atof(). SQLite does not really use these functions. It has its
3471: ** own equivalent internal routines. The atoi() and atof() names are
3472: ** used in the table for brevity and because they are familiar to most
3473: ** C programmers.
3474: **
3475: ** Note that when type conversions occur, pointers returned by prior
3476: ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
3477: ** sqlite3_column_text16() may be invalidated.
3478: ** Type conversions and pointer invalidations might occur
3479: ** in the following cases:
3480: **
3481: ** <ul>
3482: ** <li> The initial content is a BLOB and sqlite3_column_text() or
3483: ** sqlite3_column_text16() is called. A zero-terminator might
3484: ** need to be added to the string.</li>
3485: ** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
3486: ** sqlite3_column_text16() is called. The content must be converted
3487: ** to UTF-16.</li>
3488: ** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
3489: ** sqlite3_column_text() is called. The content must be converted
3490: ** to UTF-8.</li>
3491: ** </ul>
3492: **
3493: ** ^Conversions between UTF-16be and UTF-16le are always done in place and do
3494: ** not invalidate a prior pointer, though of course the content of the buffer
3495: ** that the prior pointer references will have been modified. Other kinds
3496: ** of conversion are done in place when it is possible, but sometimes they
3497: ** are not possible and in those cases prior pointers are invalidated.
3498: **
3499: ** The safest and easiest to remember policy is to invoke these routines
3500: ** in one of the following ways:
3501: **
3502: ** <ul>
3503: ** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
3504: ** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
3505: ** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
3506: ** </ul>
3507: **
3508: ** In other words, you should call sqlite3_column_text(),
3509: ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
3510: ** into the desired format, then invoke sqlite3_column_bytes() or
3511: ** sqlite3_column_bytes16() to find the size of the result. Do not mix calls
3512: ** to sqlite3_column_text() or sqlite3_column_blob() with calls to
3513: ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
3514: ** with calls to sqlite3_column_bytes().
3515: **
3516: ** ^The pointers returned are valid until a type conversion occurs as
3517: ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
3518: ** [sqlite3_finalize()] is called. ^The memory space used to hold strings
3519: ** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned
3520: ** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
3521: ** [sqlite3_free()].
3522: **
3523: ** ^(If a memory allocation error occurs during the evaluation of any
3524: ** of these routines, a default value is returned. The default value
3525: ** is either the integer 0, the floating point number 0.0, or a NULL
3526: ** pointer. Subsequent calls to [sqlite3_errcode()] will return
3527: ** [SQLITE_NOMEM].)^
3528: */
3529: SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
3530: SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
3531: SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
3532: SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol);
3533: SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol);
3534: SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
3535: SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
3536: SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
3537: SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol);
3538: SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
3539:
3540: /*
3541: ** CAPI3REF: Destroy A Prepared Statement Object
3542: **
3543: ** ^The sqlite3_finalize() function is called to delete a [prepared statement].
3544: ** ^If the most recent evaluation of the statement encountered no errors
3545: ** or if the statement is never been evaluated, then sqlite3_finalize() returns
3546: ** SQLITE_OK. ^If the most recent evaluation of statement S failed, then
3547: ** sqlite3_finalize(S) returns the appropriate [error code] or
3548: ** [extended error code].
3549: **
3550: ** ^The sqlite3_finalize(S) routine can be called at any point during
3551: ** the life cycle of [prepared statement] S:
3552: ** before statement S is ever evaluated, after
3553: ** one or more calls to [sqlite3_reset()], or after any call
3554: ** to [sqlite3_step()] regardless of whether or not the statement has
3555: ** completed execution.
3556: **
3557: ** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
3558: **
3559: ** The application must finalize every [prepared statement] in order to avoid
3560: ** resource leaks. It is a grievous error for the application to try to use
3561: ** a prepared statement after it has been finalized. Any use of a prepared
3562: ** statement after it has been finalized can result in undefined and
3563: ** undesirable behavior such as segfaults and heap corruption.
3564: */
3565: SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt);
3566:
3567: /*
3568: ** CAPI3REF: Reset A Prepared Statement Object
3569: **
3570: ** The sqlite3_reset() function is called to reset a [prepared statement]
3571: ** object back to its initial state, ready to be re-executed.
3572: ** ^Any SQL statement variables that had values bound to them using
3573: ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
3574: ** Use [sqlite3_clear_bindings()] to reset the bindings.
3575: **
3576: ** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
3577: ** back to the beginning of its program.
3578: **
3579: ** ^If the most recent call to [sqlite3_step(S)] for the
3580: ** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
3581: ** or if [sqlite3_step(S)] has never before been called on S,
3582: ** then [sqlite3_reset(S)] returns [SQLITE_OK].
3583: **
3584: ** ^If the most recent call to [sqlite3_step(S)] for the
3585: ** [prepared statement] S indicated an error, then
3586: ** [sqlite3_reset(S)] returns an appropriate [error code].
3587: **
3588: ** ^The [sqlite3_reset(S)] interface does not change the values
3589: ** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
3590: */
3591: SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt);
3592:
3593: /*
3594: ** CAPI3REF: Create Or Redefine SQL Functions
3595: ** KEYWORDS: {function creation routines}
3596: ** KEYWORDS: {application-defined SQL function}
3597: ** KEYWORDS: {application-defined SQL functions}
3598: **
3599: ** ^These functions (collectively known as "function creation routines")
3600: ** are used to add SQL functions or aggregates or to redefine the behavior
3601: ** of existing SQL functions or aggregates. The only differences between
3602: ** these routines are the text encoding expected for
3603: ** the second parameter (the name of the function being created)
3604: ** and the presence or absence of a destructor callback for
3605: ** the application data pointer.
3606: **
3607: ** ^The first parameter is the [database connection] to which the SQL
3608: ** function is to be added. ^If an application uses more than one database
3609: ** connection then application-defined SQL functions must be added
3610: ** to each database connection separately.
3611: **
3612: ** ^The second parameter is the name of the SQL function to be created or
3613: ** redefined. ^The length of the name is limited to 255 bytes in a UTF-8
3614: ** representation, exclusive of the zero-terminator. ^Note that the name
3615: ** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
3616: ** ^Any attempt to create a function with a longer name
3617: ** will result in [SQLITE_MISUSE] being returned.
3618: **
3619: ** ^The third parameter (nArg)
3620: ** is the number of arguments that the SQL function or
3621: ** aggregate takes. ^If this parameter is -1, then the SQL function or
3622: ** aggregate may take any number of arguments between 0 and the limit
3623: ** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third
3624: ** parameter is less than -1 or greater than 127 then the behavior is
3625: ** undefined.
3626: **
3627: ** ^The fourth parameter, eTextRep, specifies what
3628: ** [SQLITE_UTF8 | text encoding] this SQL function prefers for
3629: ** its parameters. Every SQL function implementation must be able to work
3630: ** with UTF-8, UTF-16le, or UTF-16be. But some implementations may be
3631: ** more efficient with one encoding than another. ^An application may
3632: ** invoke sqlite3_create_function() or sqlite3_create_function16() multiple
3633: ** times with the same function but with different values of eTextRep.
3634: ** ^When multiple implementations of the same function are available, SQLite
3635: ** will pick the one that involves the least amount of data conversion.
3636: ** If there is only a single implementation which does not care what text
3637: ** encoding is used, then the fourth argument should be [SQLITE_ANY].
3638: **
3639: ** ^(The fifth parameter is an arbitrary pointer. The implementation of the
3640: ** function can gain access to this pointer using [sqlite3_user_data()].)^
3641: **
3642: ** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are
3643: ** pointers to C-language functions that implement the SQL function or
3644: ** aggregate. ^A scalar SQL function requires an implementation of the xFunc
3645: ** callback only; NULL pointers must be passed as the xStep and xFinal
3646: ** parameters. ^An aggregate SQL function requires an implementation of xStep
3647: ** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
3648: ** SQL function or aggregate, pass NULL pointers for all three function
3649: ** callbacks.
3650: **
3651: ** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL,
3652: ** then it is destructor for the application data pointer.
3653: ** The destructor is invoked when the function is deleted, either by being
3654: ** overloaded or when the database connection closes.)^
3655: ** ^The destructor is also invoked if the call to
3656: ** sqlite3_create_function_v2() fails.
3657: ** ^When the destructor callback of the tenth parameter is invoked, it
3658: ** is passed a single argument which is a copy of the application data
3659: ** pointer which was the fifth parameter to sqlite3_create_function_v2().
3660: **
3661: ** ^It is permitted to register multiple implementations of the same
3662: ** functions with the same name but with either differing numbers of
3663: ** arguments or differing preferred text encodings. ^SQLite will use
3664: ** the implementation that most closely matches the way in which the
3665: ** SQL function is used. ^A function implementation with a non-negative
3666: ** nArg parameter is a better match than a function implementation with
3667: ** a negative nArg. ^A function where the preferred text encoding
3668: ** matches the database encoding is a better
3669: ** match than a function where the encoding is different.
3670: ** ^A function where the encoding difference is between UTF16le and UTF16be
3671: ** is a closer match than a function where the encoding difference is
3672: ** between UTF8 and UTF16.
3673: **
3674: ** ^Built-in functions may be overloaded by new application-defined functions.
3675: **
3676: ** ^An application-defined function is permitted to call other
3677: ** SQLite interfaces. However, such calls must not
3678: ** close the database connection nor finalize or reset the prepared
3679: ** statement in which the function is running.
3680: */
3681: SQLITE_API int sqlite3_create_function(
3682: sqlite3 *db,
3683: const char *zFunctionName,
3684: int nArg,
3685: int eTextRep,
3686: void *pApp,
3687: void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
3688: void (*xStep)(sqlite3_context*,int,sqlite3_value**),
3689: void (*xFinal)(sqlite3_context*)
3690: );
3691: SQLITE_API int sqlite3_create_function16(
3692: sqlite3 *db,
3693: const void *zFunctionName,
3694: int nArg,
3695: int eTextRep,
3696: void *pApp,
3697: void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
3698: void (*xStep)(sqlite3_context*,int,sqlite3_value**),
3699: void (*xFinal)(sqlite3_context*)
3700: );
3701: SQLITE_API int sqlite3_create_function_v2(
3702: sqlite3 *db,
3703: const char *zFunctionName,
3704: int nArg,
3705: int eTextRep,
3706: void *pApp,
3707: void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
3708: void (*xStep)(sqlite3_context*,int,sqlite3_value**),
3709: void (*xFinal)(sqlite3_context*),
3710: void(*xDestroy)(void*)
3711: );
3712:
3713: /*
3714: ** CAPI3REF: Text Encodings
3715: **
3716: ** These constant define integer codes that represent the various
3717: ** text encodings supported by SQLite.
3718: */
3719: #define SQLITE_UTF8 1
3720: #define SQLITE_UTF16LE 2
3721: #define SQLITE_UTF16BE 3
3722: #define SQLITE_UTF16 4 /* Use native byte order */
3723: #define SQLITE_ANY 5 /* sqlite3_create_function only */
3724: #define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */
3725:
3726: /*
3727: ** CAPI3REF: Deprecated Functions
3728: ** DEPRECATED
3729: **
3730: ** These functions are [deprecated]. In order to maintain
3731: ** backwards compatibility with older code, these functions continue
3732: ** to be supported. However, new applications should avoid
3733: ** the use of these functions. To help encourage people to avoid
3734: ** using these functions, we are not going to tell you what they do.
3735: */
3736: #ifndef SQLITE_OMIT_DEPRECATED
3737: SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
3738: SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
3739: SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
3740: SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void);
3741: SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
3742: SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64);
3743: #endif
3744:
3745: /*
3746: ** CAPI3REF: Obtaining SQL Function Parameter Values
3747: **
3748: ** The C-language implementation of SQL functions and aggregates uses
3749: ** this set of interface routines to access the parameter values on
3750: ** the function or aggregate.
3751: **
3752: ** The xFunc (for scalar functions) or xStep (for aggregates) parameters
3753: ** to [sqlite3_create_function()] and [sqlite3_create_function16()]
3754: ** define callbacks that implement the SQL functions and aggregates.
3755: ** The 3rd parameter to these callbacks is an array of pointers to
3756: ** [protected sqlite3_value] objects. There is one [sqlite3_value] object for
3757: ** each parameter to the SQL function. These routines are used to
3758: ** extract values from the [sqlite3_value] objects.
3759: **
3760: ** These routines work only with [protected sqlite3_value] objects.
3761: ** Any attempt to use these routines on an [unprotected sqlite3_value]
3762: ** object results in undefined behavior.
3763: **
3764: ** ^These routines work just like the corresponding [column access functions]
3765: ** except that these routines take a single [protected sqlite3_value] object
3766: ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
3767: **
3768: ** ^The sqlite3_value_text16() interface extracts a UTF-16 string
3769: ** in the native byte-order of the host machine. ^The
3770: ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
3771: ** extract UTF-16 strings as big-endian and little-endian respectively.
3772: **
3773: ** ^(The sqlite3_value_numeric_type() interface attempts to apply
3774: ** numeric affinity to the value. This means that an attempt is
3775: ** made to convert the value to an integer or floating point. If
3776: ** such a conversion is possible without loss of information (in other
3777: ** words, if the value is a string that looks like a number)
3778: ** then the conversion is performed. Otherwise no conversion occurs.
3779: ** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
3780: **
3781: ** Please pay particular attention to the fact that the pointer returned
3782: ** from [sqlite3_value_blob()], [sqlite3_value_text()], or
3783: ** [sqlite3_value_text16()] can be invalidated by a subsequent call to
3784: ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
3785: ** or [sqlite3_value_text16()].
3786: **
3787: ** These routines must be called from the same thread as
3788: ** the SQL function that supplied the [sqlite3_value*] parameters.
3789: */
3790: SQLITE_API const void *sqlite3_value_blob(sqlite3_value*);
3791: SQLITE_API int sqlite3_value_bytes(sqlite3_value*);
3792: SQLITE_API int sqlite3_value_bytes16(sqlite3_value*);
3793: SQLITE_API double sqlite3_value_double(sqlite3_value*);
3794: SQLITE_API int sqlite3_value_int(sqlite3_value*);
3795: SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
3796: SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*);
3797: SQLITE_API const void *sqlite3_value_text16(sqlite3_value*);
3798: SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*);
3799: SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*);
3800: SQLITE_API int sqlite3_value_type(sqlite3_value*);
3801: SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*);
3802:
3803: /*
3804: ** CAPI3REF: Obtain Aggregate Function Context
3805: **
3806: ** Implementations of aggregate SQL functions use this
3807: ** routine to allocate memory for storing their state.
3808: **
3809: ** ^The first time the sqlite3_aggregate_context(C,N) routine is called
3810: ** for a particular aggregate function, SQLite
3811: ** allocates N of memory, zeroes out that memory, and returns a pointer
3812: ** to the new memory. ^On second and subsequent calls to
3813: ** sqlite3_aggregate_context() for the same aggregate function instance,
3814: ** the same buffer is returned. Sqlite3_aggregate_context() is normally
3815: ** called once for each invocation of the xStep callback and then one
3816: ** last time when the xFinal callback is invoked. ^(When no rows match
3817: ** an aggregate query, the xStep() callback of the aggregate function
3818: ** implementation is never called and xFinal() is called exactly once.
3819: ** In those cases, sqlite3_aggregate_context() might be called for the
3820: ** first time from within xFinal().)^
3821: **
3822: ** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer if N is
3823: ** less than or equal to zero or if a memory allocate error occurs.
3824: **
3825: ** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
3826: ** determined by the N parameter on first successful call. Changing the
3827: ** value of N in subsequent call to sqlite3_aggregate_context() within
3828: ** the same aggregate function instance will not resize the memory
3829: ** allocation.)^
3830: **
3831: ** ^SQLite automatically frees the memory allocated by
3832: ** sqlite3_aggregate_context() when the aggregate query concludes.
3833: **
3834: ** The first parameter must be a copy of the
3835: ** [sqlite3_context | SQL function context] that is the first parameter
3836: ** to the xStep or xFinal callback routine that implements the aggregate
3837: ** function.
3838: **
3839: ** This routine must be called from the same thread in which
3840: ** the aggregate SQL function is running.
3841: */
3842: SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
3843:
3844: /*
3845: ** CAPI3REF: User Data For Functions
3846: **
3847: ** ^The sqlite3_user_data() interface returns a copy of
3848: ** the pointer that was the pUserData parameter (the 5th parameter)
3849: ** of the [sqlite3_create_function()]
3850: ** and [sqlite3_create_function16()] routines that originally
3851: ** registered the application defined function.
3852: **
3853: ** This routine must be called from the same thread in which
3854: ** the application-defined function is running.
3855: */
3856: SQLITE_API void *sqlite3_user_data(sqlite3_context*);
3857:
3858: /*
3859: ** CAPI3REF: Database Connection For Functions
3860: **
3861: ** ^The sqlite3_context_db_handle() interface returns a copy of
3862: ** the pointer to the [database connection] (the 1st parameter)
3863: ** of the [sqlite3_create_function()]
3864: ** and [sqlite3_create_function16()] routines that originally
3865: ** registered the application defined function.
3866: */
3867: SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
3868:
3869: /*
3870: ** CAPI3REF: Function Auxiliary Data
3871: **
3872: ** The following two functions may be used by scalar SQL functions to
3873: ** associate metadata with argument values. If the same value is passed to
3874: ** multiple invocations of the same SQL function during query execution, under
3875: ** some circumstances the associated metadata may be preserved. This may
3876: ** be used, for example, to add a regular-expression matching scalar
3877: ** function. The compiled version of the regular expression is stored as
3878: ** metadata associated with the SQL value passed as the regular expression
3879: ** pattern. The compiled regular expression can be reused on multiple
3880: ** invocations of the same function so that the original pattern string
3881: ** does not need to be recompiled on each invocation.
3882: **
3883: ** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata
3884: ** associated by the sqlite3_set_auxdata() function with the Nth argument
3885: ** value to the application-defined function. ^If no metadata has been ever
3886: ** been set for the Nth argument of the function, or if the corresponding
3887: ** function parameter has changed since the meta-data was set,
3888: ** then sqlite3_get_auxdata() returns a NULL pointer.
3889: **
3890: ** ^The sqlite3_set_auxdata() interface saves the metadata
3891: ** pointed to by its 3rd parameter as the metadata for the N-th
3892: ** argument of the application-defined function. Subsequent
3893: ** calls to sqlite3_get_auxdata() might return this data, if it has
3894: ** not been destroyed.
3895: ** ^If it is not NULL, SQLite will invoke the destructor
3896: ** function given by the 4th parameter to sqlite3_set_auxdata() on
3897: ** the metadata when the corresponding function parameter changes
3898: ** or when the SQL statement completes, whichever comes first.
3899: **
3900: ** SQLite is free to call the destructor and drop metadata on any
3901: ** parameter of any function at any time. ^The only guarantee is that
3902: ** the destructor will be called before the metadata is dropped.
3903: **
3904: ** ^(In practice, metadata is preserved between function calls for
3905: ** expressions that are constant at compile time. This includes literal
3906: ** values and [parameters].)^
3907: **
3908: ** These routines must be called from the same thread in which
3909: ** the SQL function is running.
3910: */
3911: SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N);
3912: SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
3913:
3914:
3915: /*
3916: ** CAPI3REF: Constants Defining Special Destructor Behavior
3917: **
3918: ** These are special values for the destructor that is passed in as the
3919: ** final argument to routines like [sqlite3_result_blob()]. ^If the destructor
3920: ** argument is SQLITE_STATIC, it means that the content pointer is constant
3921: ** and will never change. It does not need to be destroyed. ^The
3922: ** SQLITE_TRANSIENT value means that the content will likely change in
3923: ** the near future and that SQLite should make its own private copy of
3924: ** the content before returning.
3925: **
3926: ** The typedef is necessary to work around problems in certain
3927: ** C++ compilers. See ticket #2191.
3928: */
3929: typedef void (*sqlite3_destructor_type)(void*);
3930: #define SQLITE_STATIC ((sqlite3_destructor_type)0)
3931: #define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1)
3932:
3933: /*
3934: ** CAPI3REF: Setting The Result Of An SQL Function
3935: **
3936: ** These routines are used by the xFunc or xFinal callbacks that
3937: ** implement SQL functions and aggregates. See
3938: ** [sqlite3_create_function()] and [sqlite3_create_function16()]
3939: ** for additional information.
3940: **
3941: ** These functions work very much like the [parameter binding] family of
3942: ** functions used to bind values to host parameters in prepared statements.
3943: ** Refer to the [SQL parameter] documentation for additional information.
3944: **
3945: ** ^The sqlite3_result_blob() interface sets the result from
3946: ** an application-defined function to be the BLOB whose content is pointed
3947: ** to by the second parameter and which is N bytes long where N is the
3948: ** third parameter.
3949: **
3950: ** ^The sqlite3_result_zeroblob() interfaces set the result of
3951: ** the application-defined function to be a BLOB containing all zero
3952: ** bytes and N bytes in size, where N is the value of the 2nd parameter.
3953: **
3954: ** ^The sqlite3_result_double() interface sets the result from
3955: ** an application-defined function to be a floating point value specified
3956: ** by its 2nd argument.
3957: **
3958: ** ^The sqlite3_result_error() and sqlite3_result_error16() functions
3959: ** cause the implemented SQL function to throw an exception.
3960: ** ^SQLite uses the string pointed to by the
3961: ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
3962: ** as the text of an error message. ^SQLite interprets the error
3963: ** message string from sqlite3_result_error() as UTF-8. ^SQLite
3964: ** interprets the string from sqlite3_result_error16() as UTF-16 in native
3965: ** byte order. ^If the third parameter to sqlite3_result_error()
3966: ** or sqlite3_result_error16() is negative then SQLite takes as the error
3967: ** message all text up through the first zero character.
3968: ** ^If the third parameter to sqlite3_result_error() or
3969: ** sqlite3_result_error16() is non-negative then SQLite takes that many
3970: ** bytes (not characters) from the 2nd parameter as the error message.
3971: ** ^The sqlite3_result_error() and sqlite3_result_error16()
3972: ** routines make a private copy of the error message text before
3973: ** they return. Hence, the calling function can deallocate or
3974: ** modify the text after they return without harm.
3975: ** ^The sqlite3_result_error_code() function changes the error code
3976: ** returned by SQLite as a result of an error in a function. ^By default,
3977: ** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error()
3978: ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
3979: **
3980: ** ^The sqlite3_result_toobig() interface causes SQLite to throw an error
3981: ** indicating that a string or BLOB is too long to represent.
3982: **
3983: ** ^The sqlite3_result_nomem() interface causes SQLite to throw an error
3984: ** indicating that a memory allocation failed.
3985: **
3986: ** ^The sqlite3_result_int() interface sets the return value
3987: ** of the application-defined function to be the 32-bit signed integer
3988: ** value given in the 2nd argument.
3989: ** ^The sqlite3_result_int64() interface sets the return value
3990: ** of the application-defined function to be the 64-bit signed integer
3991: ** value given in the 2nd argument.
3992: **
3993: ** ^The sqlite3_result_null() interface sets the return value
3994: ** of the application-defined function to be NULL.
3995: **
3996: ** ^The sqlite3_result_text(), sqlite3_result_text16(),
3997: ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
3998: ** set the return value of the application-defined function to be
3999: ** a text string which is represented as UTF-8, UTF-16 native byte order,
4000: ** UTF-16 little endian, or UTF-16 big endian, respectively.
4001: ** ^SQLite takes the text result from the application from
4002: ** the 2nd parameter of the sqlite3_result_text* interfaces.
4003: ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
4004: ** is negative, then SQLite takes result text from the 2nd parameter
4005: ** through the first zero character.
4006: ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
4007: ** is non-negative, then as many bytes (not characters) of the text
4008: ** pointed to by the 2nd parameter are taken as the application-defined
4009: ** function result.
4010: ** ^If the 4th parameter to the sqlite3_result_text* interfaces
4011: ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
4012: ** function as the destructor on the text or BLOB result when it has
4013: ** finished using that result.
4014: ** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
4015: ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
4016: ** assumes that the text or BLOB result is in constant space and does not
4017: ** copy the content of the parameter nor call a destructor on the content
4018: ** when it has finished using that result.
4019: ** ^If the 4th parameter to the sqlite3_result_text* interfaces
4020: ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
4021: ** then SQLite makes a copy of the result into space obtained from
4022: ** from [sqlite3_malloc()] before it returns.
4023: **
4024: ** ^The sqlite3_result_value() interface sets the result of
4025: ** the application-defined function to be a copy the
4026: ** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The
4027: ** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
4028: ** so that the [sqlite3_value] specified in the parameter may change or
4029: ** be deallocated after sqlite3_result_value() returns without harm.
4030: ** ^A [protected sqlite3_value] object may always be used where an
4031: ** [unprotected sqlite3_value] object is required, so either
4032: ** kind of [sqlite3_value] object can be used with this interface.
4033: **
4034: ** If these routines are called from within the different thread
4035: ** than the one containing the application-defined function that received
4036: ** the [sqlite3_context] pointer, the results are undefined.
4037: */
4038: SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
4039: SQLITE_API void sqlite3_result_double(sqlite3_context*, double);
4040: SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int);
4041: SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int);
4042: SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*);
4043: SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*);
4044: SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int);
4045: SQLITE_API void sqlite3_result_int(sqlite3_context*, int);
4046: SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
4047: SQLITE_API void sqlite3_result_null(sqlite3_context*);
4048: SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
4049: SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
4050: SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
4051: SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
4052: SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
4053: SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n);
4054:
4055: /*
4056: ** CAPI3REF: Define New Collating Sequences
4057: **
4058: ** ^These functions add, remove, or modify a [collation] associated
4059: ** with the [database connection] specified as the first argument.
4060: **
4061: ** ^The name of the collation is a UTF-8 string
4062: ** for sqlite3_create_collation() and sqlite3_create_collation_v2()
4063: ** and a UTF-16 string in native byte order for sqlite3_create_collation16().
4064: ** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
4065: ** considered to be the same name.
4066: **
4067: ** ^(The third argument (eTextRep) must be one of the constants:
4068: ** <ul>
4069: ** <li> [SQLITE_UTF8],
4070: ** <li> [SQLITE_UTF16LE],
4071: ** <li> [SQLITE_UTF16BE],
4072: ** <li> [SQLITE_UTF16], or
4073: ** <li> [SQLITE_UTF16_ALIGNED].
4074: ** </ul>)^
4075: ** ^The eTextRep argument determines the encoding of strings passed
4076: ** to the collating function callback, xCallback.
4077: ** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
4078: ** force strings to be UTF16 with native byte order.
4079: ** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
4080: ** on an even byte address.
4081: **
4082: ** ^The fourth argument, pArg, is an application data pointer that is passed
4083: ** through as the first argument to the collating function callback.
4084: **
4085: ** ^The fifth argument, xCallback, is a pointer to the collating function.
4086: ** ^Multiple collating functions can be registered using the same name but
4087: ** with different eTextRep parameters and SQLite will use whichever
4088: ** function requires the least amount of data transformation.
4089: ** ^If the xCallback argument is NULL then the collating function is
4090: ** deleted. ^When all collating functions having the same name are deleted,
4091: ** that collation is no longer usable.
4092: **
4093: ** ^The collating function callback is invoked with a copy of the pArg
4094: ** application data pointer and with two strings in the encoding specified
4095: ** by the eTextRep argument. The collating function must return an
4096: ** integer that is negative, zero, or positive
4097: ** if the first string is less than, equal to, or greater than the second,
4098: ** respectively. A collating function must always return the same answer
4099: ** given the same inputs. If two or more collating functions are registered
4100: ** to the same collation name (using different eTextRep values) then all
4101: ** must give an equivalent answer when invoked with equivalent strings.
4102: ** The collating function must obey the following properties for all
4103: ** strings A, B, and C:
4104: **
4105: ** <ol>
4106: ** <li> If A==B then B==A.
4107: ** <li> If A==B and B==C then A==C.
4108: ** <li> If A<B THEN B>A.
4109: ** <li> If A<B and B<C then A<C.
4110: ** </ol>
4111: **
4112: ** If a collating function fails any of the above constraints and that
4113: ** collating function is registered and used, then the behavior of SQLite
4114: ** is undefined.
4115: **
4116: ** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
4117: ** with the addition that the xDestroy callback is invoked on pArg when
4118: ** the collating function is deleted.
4119: ** ^Collating functions are deleted when they are overridden by later
4120: ** calls to the collation creation functions or when the
4121: ** [database connection] is closed using [sqlite3_close()].
4122: **
4123: ** ^The xDestroy callback is <u>not</u> called if the
4124: ** sqlite3_create_collation_v2() function fails. Applications that invoke
4125: ** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
4126: ** check the return code and dispose of the application data pointer
4127: ** themselves rather than expecting SQLite to deal with it for them.
4128: ** This is different from every other SQLite interface. The inconsistency
4129: ** is unfortunate but cannot be changed without breaking backwards
4130: ** compatibility.
4131: **
4132: ** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
4133: */
4134: SQLITE_API int sqlite3_create_collation(
4135: sqlite3*,
4136: const char *zName,
4137: int eTextRep,
4138: void *pArg,
4139: int(*xCompare)(void*,int,const void*,int,const void*)
4140: );
4141: SQLITE_API int sqlite3_create_collation_v2(
4142: sqlite3*,
4143: const char *zName,
4144: int eTextRep,
4145: void *pArg,
4146: int(*xCompare)(void*,int,const void*,int,const void*),
4147: void(*xDestroy)(void*)
4148: );
4149: SQLITE_API int sqlite3_create_collation16(
4150: sqlite3*,
4151: const void *zName,
4152: int eTextRep,
4153: void *pArg,
4154: int(*xCompare)(void*,int,const void*,int,const void*)
4155: );
4156:
4157: /*
4158: ** CAPI3REF: Collation Needed Callbacks
4159: **
4160: ** ^To avoid having to register all collation sequences before a database
4161: ** can be used, a single callback function may be registered with the
4162: ** [database connection] to be invoked whenever an undefined collation
4163: ** sequence is required.
4164: **
4165: ** ^If the function is registered using the sqlite3_collation_needed() API,
4166: ** then it is passed the names of undefined collation sequences as strings
4167: ** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
4168: ** the names are passed as UTF-16 in machine native byte order.
4169: ** ^A call to either function replaces the existing collation-needed callback.
4170: **
4171: ** ^(When the callback is invoked, the first argument passed is a copy
4172: ** of the second argument to sqlite3_collation_needed() or
4173: ** sqlite3_collation_needed16(). The second argument is the database
4174: ** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
4175: ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
4176: ** sequence function required. The fourth parameter is the name of the
4177: ** required collation sequence.)^
4178: **
4179: ** The callback function should register the desired collation using
4180: ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
4181: ** [sqlite3_create_collation_v2()].
4182: */
4183: SQLITE_API int sqlite3_collation_needed(
4184: sqlite3*,
4185: void*,
4186: void(*)(void*,sqlite3*,int eTextRep,const char*)
4187: );
4188: SQLITE_API int sqlite3_collation_needed16(
4189: sqlite3*,
4190: void*,
4191: void(*)(void*,sqlite3*,int eTextRep,const void*)
4192: );
4193:
4194: #ifdef SQLITE_HAS_CODEC
4195: /*
4196: ** Specify the key for an encrypted database. This routine should be
4197: ** called right after sqlite3_open().
4198: **
4199: ** The code to implement this API is not available in the public release
4200: ** of SQLite.
4201: */
4202: SQLITE_API int sqlite3_key(
4203: sqlite3 *db, /* Database to be rekeyed */
4204: const void *pKey, int nKey /* The key */
4205: );
4206:
4207: /*
4208: ** Change the key on an open database. If the current database is not
4209: ** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the
4210: ** database is decrypted.
4211: **
4212: ** The code to implement this API is not available in the public release
4213: ** of SQLite.
4214: */
4215: SQLITE_API int sqlite3_rekey(
4216: sqlite3 *db, /* Database to be rekeyed */
4217: const void *pKey, int nKey /* The new key */
4218: );
4219:
4220: /*
4221: ** Specify the activation key for a SEE database. Unless
4222: ** activated, none of the SEE routines will work.
4223: */
4224: SQLITE_API void sqlite3_activate_see(
4225: const char *zPassPhrase /* Activation phrase */
4226: );
4227: #endif
4228:
4229: #ifdef SQLITE_ENABLE_CEROD
4230: /*
4231: ** Specify the activation key for a CEROD database. Unless
4232: ** activated, none of the CEROD routines will work.
4233: */
4234: SQLITE_API void sqlite3_activate_cerod(
4235: const char *zPassPhrase /* Activation phrase */
4236: );
4237: #endif
4238:
4239: /*
4240: ** CAPI3REF: Suspend Execution For A Short Time
4241: **
4242: ** The sqlite3_sleep() function causes the current thread to suspend execution
4243: ** for at least a number of milliseconds specified in its parameter.
4244: **
4245: ** If the operating system does not support sleep requests with
4246: ** millisecond time resolution, then the time will be rounded up to
4247: ** the nearest second. The number of milliseconds of sleep actually
4248: ** requested from the operating system is returned.
4249: **
4250: ** ^SQLite implements this interface by calling the xSleep()
4251: ** method of the default [sqlite3_vfs] object. If the xSleep() method
4252: ** of the default VFS is not implemented correctly, or not implemented at
4253: ** all, then the behavior of sqlite3_sleep() may deviate from the description
4254: ** in the previous paragraphs.
4255: */
4256: SQLITE_API int sqlite3_sleep(int);
4257:
4258: /*
4259: ** CAPI3REF: Name Of The Folder Holding Temporary Files
4260: **
4261: ** ^(If this global variable is made to point to a string which is
4262: ** the name of a folder (a.k.a. directory), then all temporary files
4263: ** created by SQLite when using a built-in [sqlite3_vfs | VFS]
4264: ** will be placed in that directory.)^ ^If this variable
4265: ** is a NULL pointer, then SQLite performs a search for an appropriate
4266: ** temporary file directory.
4267: **
4268: ** It is not safe to read or modify this variable in more than one
4269: ** thread at a time. It is not safe to read or modify this variable
4270: ** if a [database connection] is being used at the same time in a separate
4271: ** thread.
4272: ** It is intended that this variable be set once
4273: ** as part of process initialization and before any SQLite interface
4274: ** routines have been called and that this variable remain unchanged
4275: ** thereafter.
4276: **
4277: ** ^The [temp_store_directory pragma] may modify this variable and cause
4278: ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,
4279: ** the [temp_store_directory pragma] always assumes that any string
4280: ** that this variable points to is held in memory obtained from
4281: ** [sqlite3_malloc] and the pragma may attempt to free that memory
4282: ** using [sqlite3_free].
4283: ** Hence, if this variable is modified directly, either it should be
4284: ** made NULL or made to point to memory obtained from [sqlite3_malloc]
4285: ** or else the use of the [temp_store_directory pragma] should be avoided.
4286: */
4287: SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory;
4288:
4289: /*
4290: ** CAPI3REF: Test For Auto-Commit Mode
4291: ** KEYWORDS: {autocommit mode}
4292: **
4293: ** ^The sqlite3_get_autocommit() interface returns non-zero or
4294: ** zero if the given database connection is or is not in autocommit mode,
4295: ** respectively. ^Autocommit mode is on by default.
4296: ** ^Autocommit mode is disabled by a [BEGIN] statement.
4297: ** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
4298: **
4299: ** If certain kinds of errors occur on a statement within a multi-statement
4300: ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
4301: ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
4302: ** transaction might be rolled back automatically. The only way to
4303: ** find out whether SQLite automatically rolled back the transaction after
4304: ** an error is to use this function.
4305: **
4306: ** If another thread changes the autocommit status of the database
4307: ** connection while this routine is running, then the return value
4308: ** is undefined.
4309: */
4310: SQLITE_API int sqlite3_get_autocommit(sqlite3*);
4311:
4312: /*
4313: ** CAPI3REF: Find The Database Handle Of A Prepared Statement
4314: **
4315: ** ^The sqlite3_db_handle interface returns the [database connection] handle
4316: ** to which a [prepared statement] belongs. ^The [database connection]
4317: ** returned by sqlite3_db_handle is the same [database connection]
4318: ** that was the first argument
4319: ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
4320: ** create the statement in the first place.
4321: */
4322: SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
4323:
4324: /*
4325: ** CAPI3REF: Find the next prepared statement
4326: **
4327: ** ^This interface returns a pointer to the next [prepared statement] after
4328: ** pStmt associated with the [database connection] pDb. ^If pStmt is NULL
4329: ** then this interface returns a pointer to the first prepared statement
4330: ** associated with the database connection pDb. ^If no prepared statement
4331: ** satisfies the conditions of this routine, it returns NULL.
4332: **
4333: ** The [database connection] pointer D in a call to
4334: ** [sqlite3_next_stmt(D,S)] must refer to an open database
4335: ** connection and in particular must not be a NULL pointer.
4336: */
4337: SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
4338:
4339: /*
4340: ** CAPI3REF: Commit And Rollback Notification Callbacks
4341: **
4342: ** ^The sqlite3_commit_hook() interface registers a callback
4343: ** function to be invoked whenever a transaction is [COMMIT | committed].
4344: ** ^Any callback set by a previous call to sqlite3_commit_hook()
4345: ** for the same database connection is overridden.
4346: ** ^The sqlite3_rollback_hook() interface registers a callback
4347: ** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
4348: ** ^Any callback set by a previous call to sqlite3_rollback_hook()
4349: ** for the same database connection is overridden.
4350: ** ^The pArg argument is passed through to the callback.
4351: ** ^If the callback on a commit hook function returns non-zero,
4352: ** then the commit is converted into a rollback.
4353: **
4354: ** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
4355: ** return the P argument from the previous call of the same function
4356: ** on the same [database connection] D, or NULL for
4357: ** the first call for each function on D.
4358: **
4359: ** The callback implementation must not do anything that will modify
4360: ** the database connection that invoked the callback. Any actions
4361: ** to modify the database connection must be deferred until after the
4362: ** completion of the [sqlite3_step()] call that triggered the commit
4363: ** or rollback hook in the first place.
4364: ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
4365: ** database connections for the meaning of "modify" in this paragraph.
4366: **
4367: ** ^Registering a NULL function disables the callback.
4368: **
4369: ** ^When the commit hook callback routine returns zero, the [COMMIT]
4370: ** operation is allowed to continue normally. ^If the commit hook
4371: ** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
4372: ** ^The rollback hook is invoked on a rollback that results from a commit
4373: ** hook returning non-zero, just as it would be with any other rollback.
4374: **
4375: ** ^For the purposes of this API, a transaction is said to have been
4376: ** rolled back if an explicit "ROLLBACK" statement is executed, or
4377: ** an error or constraint causes an implicit rollback to occur.
4378: ** ^The rollback callback is not invoked if a transaction is
4379: ** automatically rolled back because the database connection is closed.
4380: **
4381: ** See also the [sqlite3_update_hook()] interface.
4382: */
4383: SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
4384: SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
4385:
4386: /*
4387: ** CAPI3REF: Data Change Notification Callbacks
4388: **
4389: ** ^The sqlite3_update_hook() interface registers a callback function
4390: ** with the [database connection] identified by the first argument
4391: ** to be invoked whenever a row is updated, inserted or deleted.
4392: ** ^Any callback set by a previous call to this function
4393: ** for the same database connection is overridden.
4394: **
4395: ** ^The second argument is a pointer to the function to invoke when a
4396: ** row is updated, inserted or deleted.
4397: ** ^The first argument to the callback is a copy of the third argument
4398: ** to sqlite3_update_hook().
4399: ** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
4400: ** or [SQLITE_UPDATE], depending on the operation that caused the callback
4401: ** to be invoked.
4402: ** ^The third and fourth arguments to the callback contain pointers to the
4403: ** database and table name containing the affected row.
4404: ** ^The final callback parameter is the [rowid] of the row.
4405: ** ^In the case of an update, this is the [rowid] after the update takes place.
4406: **
4407: ** ^(The update hook is not invoked when internal system tables are
4408: ** modified (i.e. sqlite_master and sqlite_sequence).)^
4409: **
4410: ** ^In the current implementation, the update hook
4411: ** is not invoked when duplication rows are deleted because of an
4412: ** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook
4413: ** invoked when rows are deleted using the [truncate optimization].
4414: ** The exceptions defined in this paragraph might change in a future
4415: ** release of SQLite.
4416: **
4417: ** The update hook implementation must not do anything that will modify
4418: ** the database connection that invoked the update hook. Any actions
4419: ** to modify the database connection must be deferred until after the
4420: ** completion of the [sqlite3_step()] call that triggered the update hook.
4421: ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
4422: ** database connections for the meaning of "modify" in this paragraph.
4423: **
4424: ** ^The sqlite3_update_hook(D,C,P) function
4425: ** returns the P argument from the previous call
4426: ** on the same [database connection] D, or NULL for
4427: ** the first call on D.
4428: **
4429: ** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()]
4430: ** interfaces.
4431: */
4432: SQLITE_API void *sqlite3_update_hook(
4433: sqlite3*,
4434: void(*)(void *,int ,char const *,char const *,sqlite3_int64),
4435: void*
4436: );
4437:
4438: /*
4439: ** CAPI3REF: Enable Or Disable Shared Pager Cache
4440: ** KEYWORDS: {shared cache}
4441: **
4442: ** ^(This routine enables or disables the sharing of the database cache
4443: ** and schema data structures between [database connection | connections]
4444: ** to the same database. Sharing is enabled if the argument is true
4445: ** and disabled if the argument is false.)^
4446: **
4447: ** ^Cache sharing is enabled and disabled for an entire process.
4448: ** This is a change as of SQLite version 3.5.0. In prior versions of SQLite,
4449: ** sharing was enabled or disabled for each thread separately.
4450: **
4451: ** ^(The cache sharing mode set by this interface effects all subsequent
4452: ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
4453: ** Existing database connections continue use the sharing mode
4454: ** that was in effect at the time they were opened.)^
4455: **
4456: ** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
4457: ** successfully. An [error code] is returned otherwise.)^
4458: **
4459: ** ^Shared cache is disabled by default. But this might change in
4460: ** future releases of SQLite. Applications that care about shared
4461: ** cache setting should set it explicitly.
4462: **
4463: ** See Also: [SQLite Shared-Cache Mode]
4464: */
4465: SQLITE_API int sqlite3_enable_shared_cache(int);
4466:
4467: /*
4468: ** CAPI3REF: Attempt To Free Heap Memory
4469: **
4470: ** ^The sqlite3_release_memory() interface attempts to free N bytes
4471: ** of heap memory by deallocating non-essential memory allocations
4472: ** held by the database library. Memory used to cache database
4473: ** pages to improve performance is an example of non-essential memory.
4474: ** ^sqlite3_release_memory() returns the number of bytes actually freed,
4475: ** which might be more or less than the amount requested.
4476: ** ^The sqlite3_release_memory() routine is a no-op returning zero
4477: ** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
4478: */
4479: SQLITE_API int sqlite3_release_memory(int);
4480:
4481: /*
4482: ** CAPI3REF: Impose A Limit On Heap Size
4483: **
4484: ** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
4485: ** soft limit on the amount of heap memory that may be allocated by SQLite.
4486: ** ^SQLite strives to keep heap memory utilization below the soft heap
4487: ** limit by reducing the number of pages held in the page cache
4488: ** as heap memory usages approaches the limit.
4489: ** ^The soft heap limit is "soft" because even though SQLite strives to stay
4490: ** below the limit, it will exceed the limit rather than generate
4491: ** an [SQLITE_NOMEM] error. In other words, the soft heap limit
4492: ** is advisory only.
4493: **
4494: ** ^The return value from sqlite3_soft_heap_limit64() is the size of
4495: ** the soft heap limit prior to the call. ^If the argument N is negative
4496: ** then no change is made to the soft heap limit. Hence, the current
4497: ** size of the soft heap limit can be determined by invoking
4498: ** sqlite3_soft_heap_limit64() with a negative argument.
4499: **
4500: ** ^If the argument N is zero then the soft heap limit is disabled.
4501: **
4502: ** ^(The soft heap limit is not enforced in the current implementation
4503: ** if one or more of following conditions are true:
4504: **
4505: ** <ul>
4506: ** <li> The soft heap limit is set to zero.
4507: ** <li> Memory accounting is disabled using a combination of the
4508: ** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
4509: ** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
4510: ** <li> An alternative page cache implementation is specified using
4511: ** [sqlite3_config]([SQLITE_CONFIG_PCACHE],...).
4512: ** <li> The page cache allocates from its own memory pool supplied
4513: ** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
4514: ** from the heap.
4515: ** </ul>)^
4516: **
4517: ** Beginning with SQLite version 3.7.3, the soft heap limit is enforced
4518: ** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT]
4519: ** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT],
4520: ** the soft heap limit is enforced on every memory allocation. Without
4521: ** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced
4522: ** when memory is allocated by the page cache. Testing suggests that because
4523: ** the page cache is the predominate memory user in SQLite, most
4524: ** applications will achieve adequate soft heap limit enforcement without
4525: ** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT].
4526: **
4527: ** The circumstances under which SQLite will enforce the soft heap limit may
4528: ** changes in future releases of SQLite.
4529: */
4530: SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);
4531:
4532: /*
4533: ** CAPI3REF: Deprecated Soft Heap Limit Interface
4534: ** DEPRECATED
4535: **
4536: ** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
4537: ** interface. This routine is provided for historical compatibility
4538: ** only. All new applications should use the
4539: ** [sqlite3_soft_heap_limit64()] interface rather than this one.
4540: */
4541: SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N);
4542:
4543:
4544: /*
4545: ** CAPI3REF: Extract Metadata About A Column Of A Table
4546: **
4547: ** ^This routine returns metadata about a specific column of a specific
4548: ** database table accessible using the [database connection] handle
4549: ** passed as the first function argument.
4550: **
4551: ** ^The column is identified by the second, third and fourth parameters to
4552: ** this function. ^The second parameter is either the name of the database
4553: ** (i.e. "main", "temp", or an attached database) containing the specified
4554: ** table or NULL. ^If it is NULL, then all attached databases are searched
4555: ** for the table using the same algorithm used by the database engine to
4556: ** resolve unqualified table references.
4557: **
4558: ** ^The third and fourth parameters to this function are the table and column
4559: ** name of the desired column, respectively. Neither of these parameters
4560: ** may be NULL.
4561: **
4562: ** ^Metadata is returned by writing to the memory locations passed as the 5th
4563: ** and subsequent parameters to this function. ^Any of these arguments may be
4564: ** NULL, in which case the corresponding element of metadata is omitted.
4565: **
4566: ** ^(<blockquote>
4567: ** <table border="1">
4568: ** <tr><th> Parameter <th> Output<br>Type <th> Description
4569: **
4570: ** <tr><td> 5th <td> const char* <td> Data type
4571: ** <tr><td> 6th <td> const char* <td> Name of default collation sequence
4572: ** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint
4573: ** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY
4574: ** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT]
4575: ** </table>
4576: ** </blockquote>)^
4577: **
4578: ** ^The memory pointed to by the character pointers returned for the
4579: ** declaration type and collation sequence is valid only until the next
4580: ** call to any SQLite API function.
4581: **
4582: ** ^If the specified table is actually a view, an [error code] is returned.
4583: **
4584: ** ^If the specified column is "rowid", "oid" or "_rowid_" and an
4585: ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
4586: ** parameters are set for the explicitly declared column. ^(If there is no
4587: ** explicitly declared [INTEGER PRIMARY KEY] column, then the output
4588: ** parameters are set as follows:
4589: **
4590: ** <pre>
4591: ** data type: "INTEGER"
4592: ** collation sequence: "BINARY"
4593: ** not null: 0
4594: ** primary key: 1
4595: ** auto increment: 0
4596: ** </pre>)^
4597: **
4598: ** ^(This function may load one or more schemas from database files. If an
4599: ** error occurs during this process, or if the requested table or column
4600: ** cannot be found, an [error code] is returned and an error message left
4601: ** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^
4602: **
4603: ** ^This API is only available if the library was compiled with the
4604: ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined.
4605: */
4606: SQLITE_API int sqlite3_table_column_metadata(
4607: sqlite3 *db, /* Connection handle */
4608: const char *zDbName, /* Database name or NULL */
4609: const char *zTableName, /* Table name */
4610: const char *zColumnName, /* Column name */
4611: char const **pzDataType, /* OUTPUT: Declared data type */
4612: char const **pzCollSeq, /* OUTPUT: Collation sequence name */
4613: int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */
4614: int *pPrimaryKey, /* OUTPUT: True if column part of PK */
4615: int *pAutoinc /* OUTPUT: True if column is auto-increment */
4616: );
4617:
4618: /*
4619: ** CAPI3REF: Load An Extension
4620: **
4621: ** ^This interface loads an SQLite extension library from the named file.
4622: **
4623: ** ^The sqlite3_load_extension() interface attempts to load an
4624: ** SQLite extension library contained in the file zFile.
4625: **
4626: ** ^The entry point is zProc.
4627: ** ^zProc may be 0, in which case the name of the entry point
4628: ** defaults to "sqlite3_extension_init".
4629: ** ^The sqlite3_load_extension() interface returns
4630: ** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
4631: ** ^If an error occurs and pzErrMsg is not 0, then the
4632: ** [sqlite3_load_extension()] interface shall attempt to
4633: ** fill *pzErrMsg with error message text stored in memory
4634: ** obtained from [sqlite3_malloc()]. The calling function
4635: ** should free this memory by calling [sqlite3_free()].
4636: **
4637: ** ^Extension loading must be enabled using
4638: ** [sqlite3_enable_load_extension()] prior to calling this API,
4639: ** otherwise an error will be returned.
4640: **
4641: ** See also the [load_extension() SQL function].
4642: */
4643: SQLITE_API int sqlite3_load_extension(
4644: sqlite3 *db, /* Load the extension into this database connection */
4645: const char *zFile, /* Name of the shared library containing extension */
4646: const char *zProc, /* Entry point. Derived from zFile if 0 */
4647: char **pzErrMsg /* Put error message here if not 0 */
4648: );
4649:
4650: /*
4651: ** CAPI3REF: Enable Or Disable Extension Loading
4652: **
4653: ** ^So as not to open security holes in older applications that are
4654: ** unprepared to deal with extension loading, and as a means of disabling
4655: ** extension loading while evaluating user-entered SQL, the following API
4656: ** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
4657: **
4658: ** ^Extension loading is off by default. See ticket #1863.
4659: ** ^Call the sqlite3_enable_load_extension() routine with onoff==1
4660: ** to turn extension loading on and call it with onoff==0 to turn
4661: ** it back off again.
4662: */
4663: SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
4664:
4665: /*
4666: ** CAPI3REF: Automatically Load Statically Linked Extensions
4667: **
4668: ** ^This interface causes the xEntryPoint() function to be invoked for
4669: ** each new [database connection] that is created. The idea here is that
4670: ** xEntryPoint() is the entry point for a statically linked SQLite extension
4671: ** that is to be automatically loaded into all new database connections.
4672: **
4673: ** ^(Even though the function prototype shows that xEntryPoint() takes
4674: ** no arguments and returns void, SQLite invokes xEntryPoint() with three
4675: ** arguments and expects and integer result as if the signature of the
4676: ** entry point where as follows:
4677: **
4678: ** <blockquote><pre>
4679: ** int xEntryPoint(
4680: ** sqlite3 *db,
4681: ** const char **pzErrMsg,
4682: ** const struct sqlite3_api_routines *pThunk
4683: ** );
4684: ** </pre></blockquote>)^
4685: **
4686: ** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
4687: ** point to an appropriate error message (obtained from [sqlite3_mprintf()])
4688: ** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg
4689: ** is NULL before calling the xEntryPoint(). ^SQLite will invoke
4690: ** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any
4691: ** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
4692: ** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
4693: **
4694: ** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
4695: ** on the list of automatic extensions is a harmless no-op. ^No entry point
4696: ** will be called more than once for each database connection that is opened.
4697: **
4698: ** See also: [sqlite3_reset_auto_extension()].
4699: */
4700: SQLITE_API int sqlite3_auto_extension(void (*xEntryPoint)(void));
4701:
4702: /*
4703: ** CAPI3REF: Reset Automatic Extension Loading
4704: **
4705: ** ^This interface disables all automatic extensions previously
4706: ** registered using [sqlite3_auto_extension()].
4707: */
4708: SQLITE_API void sqlite3_reset_auto_extension(void);
4709:
4710: /*
4711: ** The interface to the virtual-table mechanism is currently considered
4712: ** to be experimental. The interface might change in incompatible ways.
4713: ** If this is a problem for you, do not use the interface at this time.
4714: **
4715: ** When the virtual-table mechanism stabilizes, we will declare the
4716: ** interface fixed, support it indefinitely, and remove this comment.
4717: */
4718:
4719: /*
4720: ** Structures used by the virtual table interface
4721: */
4722: typedef struct sqlite3_vtab sqlite3_vtab;
4723: typedef struct sqlite3_index_info sqlite3_index_info;
4724: typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
4725: typedef struct sqlite3_module sqlite3_module;
4726:
4727: /*
4728: ** CAPI3REF: Virtual Table Object
4729: ** KEYWORDS: sqlite3_module {virtual table module}
4730: **
4731: ** This structure, sometimes called a "virtual table module",
4732: ** defines the implementation of a [virtual tables].
4733: ** This structure consists mostly of methods for the module.
4734: **
4735: ** ^A virtual table module is created by filling in a persistent
4736: ** instance of this structure and passing a pointer to that instance
4737: ** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
4738: ** ^The registration remains valid until it is replaced by a different
4739: ** module or until the [database connection] closes. The content
4740: ** of this structure must not change while it is registered with
4741: ** any database connection.
4742: */
4743: struct sqlite3_module {
4744: int iVersion;
4745: int (*xCreate)(sqlite3*, void *pAux,
4746: int argc, const char *const*argv,
4747: sqlite3_vtab **ppVTab, char**);
4748: int (*xConnect)(sqlite3*, void *pAux,
4749: int argc, const char *const*argv,
4750: sqlite3_vtab **ppVTab, char**);
4751: int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
4752: int (*xDisconnect)(sqlite3_vtab *pVTab);
4753: int (*xDestroy)(sqlite3_vtab *pVTab);
4754: int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
4755: int (*xClose)(sqlite3_vtab_cursor*);
4756: int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
4757: int argc, sqlite3_value **argv);
4758: int (*xNext)(sqlite3_vtab_cursor*);
4759: int (*xEof)(sqlite3_vtab_cursor*);
4760: int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
4761: int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
4762: int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
4763: int (*xBegin)(sqlite3_vtab *pVTab);
4764: int (*xSync)(sqlite3_vtab *pVTab);
4765: int (*xCommit)(sqlite3_vtab *pVTab);
4766: int (*xRollback)(sqlite3_vtab *pVTab);
4767: int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
4768: void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
4769: void **ppArg);
4770: int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
4771: /* The methods above are in version 1 of the sqlite_module object. Those
4772: ** below are for version 2 and greater. */
4773: int (*xSavepoint)(sqlite3_vtab *pVTab, int);
4774: int (*xRelease)(sqlite3_vtab *pVTab, int);
4775: int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
4776: };
4777:
4778: /*
4779: ** CAPI3REF: Virtual Table Indexing Information
4780: ** KEYWORDS: sqlite3_index_info
4781: **
4782: ** The sqlite3_index_info structure and its substructures is used as part
4783: ** of the [virtual table] interface to
4784: ** pass information into and receive the reply from the [xBestIndex]
4785: ** method of a [virtual table module]. The fields under **Inputs** are the
4786: ** inputs to xBestIndex and are read-only. xBestIndex inserts its
4787: ** results into the **Outputs** fields.
4788: **
4789: ** ^(The aConstraint[] array records WHERE clause constraints of the form:
4790: **
4791: ** <blockquote>column OP expr</blockquote>
4792: **
4793: ** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is
4794: ** stored in aConstraint[].op using one of the
4795: ** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
4796: ** ^(The index of the column is stored in
4797: ** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the
4798: ** expr on the right-hand side can be evaluated (and thus the constraint
4799: ** is usable) and false if it cannot.)^
4800: **
4801: ** ^The optimizer automatically inverts terms of the form "expr OP column"
4802: ** and makes other simplifications to the WHERE clause in an attempt to
4803: ** get as many WHERE clause terms into the form shown above as possible.
4804: ** ^The aConstraint[] array only reports WHERE clause terms that are
4805: ** relevant to the particular virtual table being queried.
4806: **
4807: ** ^Information about the ORDER BY clause is stored in aOrderBy[].
4808: ** ^Each term of aOrderBy records a column of the ORDER BY clause.
4809: **
4810: ** The [xBestIndex] method must fill aConstraintUsage[] with information
4811: ** about what parameters to pass to xFilter. ^If argvIndex>0 then
4812: ** the right-hand side of the corresponding aConstraint[] is evaluated
4813: ** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit
4814: ** is true, then the constraint is assumed to be fully handled by the
4815: ** virtual table and is not checked again by SQLite.)^
4816: **
4817: ** ^The idxNum and idxPtr values are recorded and passed into the
4818: ** [xFilter] method.
4819: ** ^[sqlite3_free()] is used to free idxPtr if and only if
4820: ** needToFreeIdxPtr is true.
4821: **
4822: ** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
4823: ** the correct order to satisfy the ORDER BY clause so that no separate
4824: ** sorting step is required.
4825: **
4826: ** ^The estimatedCost value is an estimate of the cost of doing the
4827: ** particular lookup. A full scan of a table with N entries should have
4828: ** a cost of N. A binary search of a table of N entries should have a
4829: ** cost of approximately log(N).
4830: */
4831: struct sqlite3_index_info {
4832: /* Inputs */
4833: int nConstraint; /* Number of entries in aConstraint */
4834: struct sqlite3_index_constraint {
4835: int iColumn; /* Column on left-hand side of constraint */
4836: unsigned char op; /* Constraint operator */
4837: unsigned char usable; /* True if this constraint is usable */
4838: int iTermOffset; /* Used internally - xBestIndex should ignore */
4839: } *aConstraint; /* Table of WHERE clause constraints */
4840: int nOrderBy; /* Number of terms in the ORDER BY clause */
4841: struct sqlite3_index_orderby {
4842: int iColumn; /* Column number */
4843: unsigned char desc; /* True for DESC. False for ASC. */
4844: } *aOrderBy; /* The ORDER BY clause */
4845: /* Outputs */
4846: struct sqlite3_index_constraint_usage {
4847: int argvIndex; /* if >0, constraint is part of argv to xFilter */
4848: unsigned char omit; /* Do not code a test for this constraint */
4849: } *aConstraintUsage;
4850: int idxNum; /* Number used to identify the index */
4851: char *idxStr; /* String, possibly obtained from sqlite3_malloc */
4852: int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */
4853: int orderByConsumed; /* True if output is already ordered */
4854: double estimatedCost; /* Estimated cost of using this index */
4855: };
4856:
4857: /*
4858: ** CAPI3REF: Virtual Table Constraint Operator Codes
4859: **
4860: ** These macros defined the allowed values for the
4861: ** [sqlite3_index_info].aConstraint[].op field. Each value represents
4862: ** an operator that is part of a constraint term in the wHERE clause of
4863: ** a query that uses a [virtual table].
4864: */
4865: #define SQLITE_INDEX_CONSTRAINT_EQ 2
4866: #define SQLITE_INDEX_CONSTRAINT_GT 4
4867: #define SQLITE_INDEX_CONSTRAINT_LE 8
4868: #define SQLITE_INDEX_CONSTRAINT_LT 16
4869: #define SQLITE_INDEX_CONSTRAINT_GE 32
4870: #define SQLITE_INDEX_CONSTRAINT_MATCH 64
4871:
4872: /*
4873: ** CAPI3REF: Register A Virtual Table Implementation
4874: **
4875: ** ^These routines are used to register a new [virtual table module] name.
4876: ** ^Module names must be registered before
4877: ** creating a new [virtual table] using the module and before using a
4878: ** preexisting [virtual table] for the module.
4879: **
4880: ** ^The module name is registered on the [database connection] specified
4881: ** by the first parameter. ^The name of the module is given by the
4882: ** second parameter. ^The third parameter is a pointer to
4883: ** the implementation of the [virtual table module]. ^The fourth
4884: ** parameter is an arbitrary client data pointer that is passed through
4885: ** into the [xCreate] and [xConnect] methods of the virtual table module
4886: ** when a new virtual table is be being created or reinitialized.
4887: **
4888: ** ^The sqlite3_create_module_v2() interface has a fifth parameter which
4889: ** is a pointer to a destructor for the pClientData. ^SQLite will
4890: ** invoke the destructor function (if it is not NULL) when SQLite
4891: ** no longer needs the pClientData pointer. ^The destructor will also
4892: ** be invoked if the call to sqlite3_create_module_v2() fails.
4893: ** ^The sqlite3_create_module()
4894: ** interface is equivalent to sqlite3_create_module_v2() with a NULL
4895: ** destructor.
4896: */
4897: SQLITE_API int sqlite3_create_module(
4898: sqlite3 *db, /* SQLite connection to register module with */
4899: const char *zName, /* Name of the module */
4900: const sqlite3_module *p, /* Methods for the module */
4901: void *pClientData /* Client data for xCreate/xConnect */
4902: );
4903: SQLITE_API int sqlite3_create_module_v2(
4904: sqlite3 *db, /* SQLite connection to register module with */
4905: const char *zName, /* Name of the module */
4906: const sqlite3_module *p, /* Methods for the module */
4907: void *pClientData, /* Client data for xCreate/xConnect */
4908: void(*xDestroy)(void*) /* Module destructor function */
4909: );
4910:
4911: /*
4912: ** CAPI3REF: Virtual Table Instance Object
4913: ** KEYWORDS: sqlite3_vtab
4914: **
4915: ** Every [virtual table module] implementation uses a subclass
4916: ** of this object to describe a particular instance
4917: ** of the [virtual table]. Each subclass will
4918: ** be tailored to the specific needs of the module implementation.
4919: ** The purpose of this superclass is to define certain fields that are
4920: ** common to all module implementations.
4921: **
4922: ** ^Virtual tables methods can set an error message by assigning a
4923: ** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should
4924: ** take care that any prior string is freed by a call to [sqlite3_free()]
4925: ** prior to assigning a new string to zErrMsg. ^After the error message
4926: ** is delivered up to the client application, the string will be automatically
4927: ** freed by sqlite3_free() and the zErrMsg field will be zeroed.
4928: */
4929: struct sqlite3_vtab {
4930: const sqlite3_module *pModule; /* The module for this virtual table */
4931: int nRef; /* NO LONGER USED */
4932: char *zErrMsg; /* Error message from sqlite3_mprintf() */
4933: /* Virtual table implementations will typically add additional fields */
4934: };
4935:
4936: /*
4937: ** CAPI3REF: Virtual Table Cursor Object
4938: ** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
4939: **
4940: ** Every [virtual table module] implementation uses a subclass of the
4941: ** following structure to describe cursors that point into the
4942: ** [virtual table] and are used
4943: ** to loop through the virtual table. Cursors are created using the
4944: ** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
4945: ** by the [sqlite3_module.xClose | xClose] method. Cursors are used
4946: ** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
4947: ** of the module. Each module implementation will define
4948: ** the content of a cursor structure to suit its own needs.
4949: **
4950: ** This superclass exists in order to define fields of the cursor that
4951: ** are common to all implementations.
4952: */
4953: struct sqlite3_vtab_cursor {
4954: sqlite3_vtab *pVtab; /* Virtual table of this cursor */
4955: /* Virtual table implementations will typically add additional fields */
4956: };
4957:
4958: /*
4959: ** CAPI3REF: Declare The Schema Of A Virtual Table
4960: **
4961: ** ^The [xCreate] and [xConnect] methods of a
4962: ** [virtual table module] call this interface
4963: ** to declare the format (the names and datatypes of the columns) of
4964: ** the virtual tables they implement.
4965: */
4966: SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
4967:
4968: /*
4969: ** CAPI3REF: Overload A Function For A Virtual Table
4970: **
4971: ** ^(Virtual tables can provide alternative implementations of functions
4972: ** using the [xFindFunction] method of the [virtual table module].
4973: ** But global versions of those functions
4974: ** must exist in order to be overloaded.)^
4975: **
4976: ** ^(This API makes sure a global version of a function with a particular
4977: ** name and number of parameters exists. If no such function exists
4978: ** before this API is called, a new function is created.)^ ^The implementation
4979: ** of the new function always causes an exception to be thrown. So
4980: ** the new function is not good for anything by itself. Its only
4981: ** purpose is to be a placeholder function that can be overloaded
4982: ** by a [virtual table].
4983: */
4984: SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
4985:
4986: /*
4987: ** The interface to the virtual-table mechanism defined above (back up
4988: ** to a comment remarkably similar to this one) is currently considered
4989: ** to be experimental. The interface might change in incompatible ways.
4990: ** If this is a problem for you, do not use the interface at this time.
4991: **
4992: ** When the virtual-table mechanism stabilizes, we will declare the
4993: ** interface fixed, support it indefinitely, and remove this comment.
4994: */
4995:
4996: /*
4997: ** CAPI3REF: A Handle To An Open BLOB
4998: ** KEYWORDS: {BLOB handle} {BLOB handles}
4999: **
5000: ** An instance of this object represents an open BLOB on which
5001: ** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
5002: ** ^Objects of this type are created by [sqlite3_blob_open()]
5003: ** and destroyed by [sqlite3_blob_close()].
5004: ** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
5005: ** can be used to read or write small subsections of the BLOB.
5006: ** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
5007: */
5008: typedef struct sqlite3_blob sqlite3_blob;
5009:
5010: /*
5011: ** CAPI3REF: Open A BLOB For Incremental I/O
5012: **
5013: ** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
5014: ** in row iRow, column zColumn, table zTable in database zDb;
5015: ** in other words, the same BLOB that would be selected by:
5016: **
5017: ** <pre>
5018: ** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
5019: ** </pre>)^
5020: **
5021: ** ^If the flags parameter is non-zero, then the BLOB is opened for read
5022: ** and write access. ^If it is zero, the BLOB is opened for read access.
5023: ** ^It is not possible to open a column that is part of an index or primary
5024: ** key for writing. ^If [foreign key constraints] are enabled, it is
5025: ** not possible to open a column that is part of a [child key] for writing.
5026: **
5027: ** ^Note that the database name is not the filename that contains
5028: ** the database but rather the symbolic name of the database that
5029: ** appears after the AS keyword when the database is connected using [ATTACH].
5030: ** ^For the main database file, the database name is "main".
5031: ** ^For TEMP tables, the database name is "temp".
5032: **
5033: ** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written
5034: ** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set
5035: ** to be a null pointer.)^
5036: ** ^This function sets the [database connection] error code and message
5037: ** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related
5038: ** functions. ^Note that the *ppBlob variable is always initialized in a
5039: ** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob
5040: ** regardless of the success or failure of this routine.
5041: **
5042: ** ^(If the row that a BLOB handle points to is modified by an
5043: ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
5044: ** then the BLOB handle is marked as "expired".
5045: ** This is true if any column of the row is changed, even a column
5046: ** other than the one the BLOB handle is open on.)^
5047: ** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
5048: ** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
5049: ** ^(Changes written into a BLOB prior to the BLOB expiring are not
5050: ** rolled back by the expiration of the BLOB. Such changes will eventually
5051: ** commit if the transaction continues to completion.)^
5052: **
5053: ** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
5054: ** the opened blob. ^The size of a blob may not be changed by this
5055: ** interface. Use the [UPDATE] SQL command to change the size of a
5056: ** blob.
5057: **
5058: ** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
5059: ** and the built-in [zeroblob] SQL function can be used, if desired,
5060: ** to create an empty, zero-filled blob in which to read or write using
5061: ** this interface.
5062: **
5063: ** To avoid a resource leak, every open [BLOB handle] should eventually
5064: ** be released by a call to [sqlite3_blob_close()].
5065: */
5066: SQLITE_API int sqlite3_blob_open(
5067: sqlite3*,
5068: const char *zDb,
5069: const char *zTable,
5070: const char *zColumn,
5071: sqlite3_int64 iRow,
5072: int flags,
5073: sqlite3_blob **ppBlob
5074: );
5075:
5076: /*
5077: ** CAPI3REF: Move a BLOB Handle to a New Row
5078: **
5079: ** ^This function is used to move an existing blob handle so that it points
5080: ** to a different row of the same database table. ^The new row is identified
5081: ** by the rowid value passed as the second argument. Only the row can be
5082: ** changed. ^The database, table and column on which the blob handle is open
5083: ** remain the same. Moving an existing blob handle to a new row can be
5084: ** faster than closing the existing handle and opening a new one.
5085: **
5086: ** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
5087: ** it must exist and there must be either a blob or text value stored in
5088: ** the nominated column.)^ ^If the new row is not present in the table, or if
5089: ** it does not contain a blob or text value, or if another error occurs, an
5090: ** SQLite error code is returned and the blob handle is considered aborted.
5091: ** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
5092: ** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
5093: ** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
5094: ** always returns zero.
5095: **
5096: ** ^This function sets the database handle error code and message.
5097: */
5098: SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
5099:
5100: /*
5101: ** CAPI3REF: Close A BLOB Handle
5102: **
5103: ** ^Closes an open [BLOB handle].
5104: **
5105: ** ^Closing a BLOB shall cause the current transaction to commit
5106: ** if there are no other BLOBs, no pending prepared statements, and the
5107: ** database connection is in [autocommit mode].
5108: ** ^If any writes were made to the BLOB, they might be held in cache
5109: ** until the close operation if they will fit.
5110: **
5111: ** ^(Closing the BLOB often forces the changes
5112: ** out to disk and so if any I/O errors occur, they will likely occur
5113: ** at the time when the BLOB is closed. Any errors that occur during
5114: ** closing are reported as a non-zero return value.)^
5115: **
5116: ** ^(The BLOB is closed unconditionally. Even if this routine returns
5117: ** an error code, the BLOB is still closed.)^
5118: **
5119: ** ^Calling this routine with a null pointer (such as would be returned
5120: ** by a failed call to [sqlite3_blob_open()]) is a harmless no-op.
5121: */
5122: SQLITE_API int sqlite3_blob_close(sqlite3_blob *);
5123:
5124: /*
5125: ** CAPI3REF: Return The Size Of An Open BLOB
5126: **
5127: ** ^Returns the size in bytes of the BLOB accessible via the
5128: ** successfully opened [BLOB handle] in its only argument. ^The
5129: ** incremental blob I/O routines can only read or overwriting existing
5130: ** blob content; they cannot change the size of a blob.
5131: **
5132: ** This routine only works on a [BLOB handle] which has been created
5133: ** by a prior successful call to [sqlite3_blob_open()] and which has not
5134: ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
5135: ** to this routine results in undefined and probably undesirable behavior.
5136: */
5137: SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *);
5138:
5139: /*
5140: ** CAPI3REF: Read Data From A BLOB Incrementally
5141: **
5142: ** ^(This function is used to read data from an open [BLOB handle] into a
5143: ** caller-supplied buffer. N bytes of data are copied into buffer Z
5144: ** from the open BLOB, starting at offset iOffset.)^
5145: **
5146: ** ^If offset iOffset is less than N bytes from the end of the BLOB,
5147: ** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is
5148: ** less than zero, [SQLITE_ERROR] is returned and no data is read.
5149: ** ^The size of the blob (and hence the maximum value of N+iOffset)
5150: ** can be determined using the [sqlite3_blob_bytes()] interface.
5151: **
5152: ** ^An attempt to read from an expired [BLOB handle] fails with an
5153: ** error code of [SQLITE_ABORT].
5154: **
5155: ** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
5156: ** Otherwise, an [error code] or an [extended error code] is returned.)^
5157: **
5158: ** This routine only works on a [BLOB handle] which has been created
5159: ** by a prior successful call to [sqlite3_blob_open()] and which has not
5160: ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
5161: ** to this routine results in undefined and probably undesirable behavior.
5162: **
5163: ** See also: [sqlite3_blob_write()].
5164: */
5165: SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
5166:
5167: /*
5168: ** CAPI3REF: Write Data Into A BLOB Incrementally
5169: **
5170: ** ^This function is used to write data into an open [BLOB handle] from a
5171: ** caller-supplied buffer. ^N bytes of data are copied from the buffer Z
5172: ** into the open BLOB, starting at offset iOffset.
5173: **
5174: ** ^If the [BLOB handle] passed as the first argument was not opened for
5175: ** writing (the flags parameter to [sqlite3_blob_open()] was zero),
5176: ** this function returns [SQLITE_READONLY].
5177: **
5178: ** ^This function may only modify the contents of the BLOB; it is
5179: ** not possible to increase the size of a BLOB using this API.
5180: ** ^If offset iOffset is less than N bytes from the end of the BLOB,
5181: ** [SQLITE_ERROR] is returned and no data is written. ^If N is
5182: ** less than zero [SQLITE_ERROR] is returned and no data is written.
5183: ** The size of the BLOB (and hence the maximum value of N+iOffset)
5184: ** can be determined using the [sqlite3_blob_bytes()] interface.
5185: **
5186: ** ^An attempt to write to an expired [BLOB handle] fails with an
5187: ** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred
5188: ** before the [BLOB handle] expired are not rolled back by the
5189: ** expiration of the handle, though of course those changes might
5190: ** have been overwritten by the statement that expired the BLOB handle
5191: ** or by other independent statements.
5192: **
5193: ** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
5194: ** Otherwise, an [error code] or an [extended error code] is returned.)^
5195: **
5196: ** This routine only works on a [BLOB handle] which has been created
5197: ** by a prior successful call to [sqlite3_blob_open()] and which has not
5198: ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
5199: ** to this routine results in undefined and probably undesirable behavior.
5200: **
5201: ** See also: [sqlite3_blob_read()].
5202: */
5203: SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
5204:
5205: /*
5206: ** CAPI3REF: Virtual File System Objects
5207: **
5208: ** A virtual filesystem (VFS) is an [sqlite3_vfs] object
5209: ** that SQLite uses to interact
5210: ** with the underlying operating system. Most SQLite builds come with a
5211: ** single default VFS that is appropriate for the host computer.
5212: ** New VFSes can be registered and existing VFSes can be unregistered.
5213: ** The following interfaces are provided.
5214: **
5215: ** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
5216: ** ^Names are case sensitive.
5217: ** ^Names are zero-terminated UTF-8 strings.
5218: ** ^If there is no match, a NULL pointer is returned.
5219: ** ^If zVfsName is NULL then the default VFS is returned.
5220: **
5221: ** ^New VFSes are registered with sqlite3_vfs_register().
5222: ** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
5223: ** ^The same VFS can be registered multiple times without injury.
5224: ** ^To make an existing VFS into the default VFS, register it again
5225: ** with the makeDflt flag set. If two different VFSes with the
5226: ** same name are registered, the behavior is undefined. If a
5227: ** VFS is registered with a name that is NULL or an empty string,
5228: ** then the behavior is undefined.
5229: **
5230: ** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
5231: ** ^(If the default VFS is unregistered, another VFS is chosen as
5232: ** the default. The choice for the new VFS is arbitrary.)^
5233: */
5234: SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
5235: SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
5236: SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*);
5237:
5238: /*
5239: ** CAPI3REF: Mutexes
5240: **
5241: ** The SQLite core uses these routines for thread
5242: ** synchronization. Though they are intended for internal
5243: ** use by SQLite, code that links against SQLite is
5244: ** permitted to use any of these routines.
5245: **
5246: ** The SQLite source code contains multiple implementations
5247: ** of these mutex routines. An appropriate implementation
5248: ** is selected automatically at compile-time. ^(The following
5249: ** implementations are available in the SQLite core:
5250: **
5251: ** <ul>
5252: ** <li> SQLITE_MUTEX_OS2
5253: ** <li> SQLITE_MUTEX_PTHREAD
5254: ** <li> SQLITE_MUTEX_W32
5255: ** <li> SQLITE_MUTEX_NOOP
5256: ** </ul>)^
5257: **
5258: ** ^The SQLITE_MUTEX_NOOP implementation is a set of routines
5259: ** that does no real locking and is appropriate for use in
5260: ** a single-threaded application. ^The SQLITE_MUTEX_OS2,
5261: ** SQLITE_MUTEX_PTHREAD, and SQLITE_MUTEX_W32 implementations
5262: ** are appropriate for use on OS/2, Unix, and Windows.
5263: **
5264: ** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
5265: ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
5266: ** implementation is included with the library. In this case the
5267: ** application must supply a custom mutex implementation using the
5268: ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
5269: ** before calling sqlite3_initialize() or any other public sqlite3_
5270: ** function that calls sqlite3_initialize().)^
5271: **
5272: ** ^The sqlite3_mutex_alloc() routine allocates a new
5273: ** mutex and returns a pointer to it. ^If it returns NULL
5274: ** that means that a mutex could not be allocated. ^SQLite
5275: ** will unwind its stack and return an error. ^(The argument
5276: ** to sqlite3_mutex_alloc() is one of these integer constants:
5277: **
5278: ** <ul>
5279: ** <li> SQLITE_MUTEX_FAST
5280: ** <li> SQLITE_MUTEX_RECURSIVE
5281: ** <li> SQLITE_MUTEX_STATIC_MASTER
5282: ** <li> SQLITE_MUTEX_STATIC_MEM
5283: ** <li> SQLITE_MUTEX_STATIC_MEM2
5284: ** <li> SQLITE_MUTEX_STATIC_PRNG
5285: ** <li> SQLITE_MUTEX_STATIC_LRU
5286: ** <li> SQLITE_MUTEX_STATIC_LRU2
5287: ** </ul>)^
5288: **
5289: ** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
5290: ** cause sqlite3_mutex_alloc() to create
5291: ** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
5292: ** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
5293: ** The mutex implementation does not need to make a distinction
5294: ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
5295: ** not want to. ^SQLite will only request a recursive mutex in
5296: ** cases where it really needs one. ^If a faster non-recursive mutex
5297: ** implementation is available on the host platform, the mutex subsystem
5298: ** might return such a mutex in response to SQLITE_MUTEX_FAST.
5299: **
5300: ** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
5301: ** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
5302: ** a pointer to a static preexisting mutex. ^Six static mutexes are
5303: ** used by the current version of SQLite. Future versions of SQLite
5304: ** may add additional static mutexes. Static mutexes are for internal
5305: ** use by SQLite only. Applications that use SQLite mutexes should
5306: ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
5307: ** SQLITE_MUTEX_RECURSIVE.
5308: **
5309: ** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
5310: ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
5311: ** returns a different mutex on every call. ^But for the static
5312: ** mutex types, the same mutex is returned on every call that has
5313: ** the same type number.
5314: **
5315: ** ^The sqlite3_mutex_free() routine deallocates a previously
5316: ** allocated dynamic mutex. ^SQLite is careful to deallocate every
5317: ** dynamic mutex that it allocates. The dynamic mutexes must not be in
5318: ** use when they are deallocated. Attempting to deallocate a static
5319: ** mutex results in undefined behavior. ^SQLite never deallocates
5320: ** a static mutex.
5321: **
5322: ** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
5323: ** to enter a mutex. ^If another thread is already within the mutex,
5324: ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
5325: ** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
5326: ** upon successful entry. ^(Mutexes created using
5327: ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
5328: ** In such cases the,
5329: ** mutex must be exited an equal number of times before another thread
5330: ** can enter.)^ ^(If the same thread tries to enter any other
5331: ** kind of mutex more than once, the behavior is undefined.
5332: ** SQLite will never exhibit
5333: ** such behavior in its own use of mutexes.)^
5334: **
5335: ** ^(Some systems (for example, Windows 95) do not support the operation
5336: ** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try()
5337: ** will always return SQLITE_BUSY. The SQLite core only ever uses
5338: ** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^
5339: **
5340: ** ^The sqlite3_mutex_leave() routine exits a mutex that was
5341: ** previously entered by the same thread. ^(The behavior
5342: ** is undefined if the mutex is not currently entered by the
5343: ** calling thread or is not currently allocated. SQLite will
5344: ** never do either.)^
5345: **
5346: ** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
5347: ** sqlite3_mutex_leave() is a NULL pointer, then all three routines
5348: ** behave as no-ops.
5349: **
5350: ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
5351: */
5352: SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int);
5353: SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*);
5354: SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*);
5355: SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*);
5356: SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*);
5357:
5358: /*
5359: ** CAPI3REF: Mutex Methods Object
5360: **
5361: ** An instance of this structure defines the low-level routines
5362: ** used to allocate and use mutexes.
5363: **
5364: ** Usually, the default mutex implementations provided by SQLite are
5365: ** sufficient, however the user has the option of substituting a custom
5366: ** implementation for specialized deployments or systems for which SQLite
5367: ** does not provide a suitable implementation. In this case, the user
5368: ** creates and populates an instance of this structure to pass
5369: ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
5370: ** Additionally, an instance of this structure can be used as an
5371: ** output variable when querying the system for the current mutex
5372: ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
5373: **
5374: ** ^The xMutexInit method defined by this structure is invoked as
5375: ** part of system initialization by the sqlite3_initialize() function.
5376: ** ^The xMutexInit routine is called by SQLite exactly once for each
5377: ** effective call to [sqlite3_initialize()].
5378: **
5379: ** ^The xMutexEnd method defined by this structure is invoked as
5380: ** part of system shutdown by the sqlite3_shutdown() function. The
5381: ** implementation of this method is expected to release all outstanding
5382: ** resources obtained by the mutex methods implementation, especially
5383: ** those obtained by the xMutexInit method. ^The xMutexEnd()
5384: ** interface is invoked exactly once for each call to [sqlite3_shutdown()].
5385: **
5386: ** ^(The remaining seven methods defined by this structure (xMutexAlloc,
5387: ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
5388: ** xMutexNotheld) implement the following interfaces (respectively):
5389: **
5390: ** <ul>
5391: ** <li> [sqlite3_mutex_alloc()] </li>
5392: ** <li> [sqlite3_mutex_free()] </li>
5393: ** <li> [sqlite3_mutex_enter()] </li>
5394: ** <li> [sqlite3_mutex_try()] </li>
5395: ** <li> [sqlite3_mutex_leave()] </li>
5396: ** <li> [sqlite3_mutex_held()] </li>
5397: ** <li> [sqlite3_mutex_notheld()] </li>
5398: ** </ul>)^
5399: **
5400: ** The only difference is that the public sqlite3_XXX functions enumerated
5401: ** above silently ignore any invocations that pass a NULL pointer instead
5402: ** of a valid mutex handle. The implementations of the methods defined
5403: ** by this structure are not required to handle this case, the results
5404: ** of passing a NULL pointer instead of a valid mutex handle are undefined
5405: ** (i.e. it is acceptable to provide an implementation that segfaults if
5406: ** it is passed a NULL pointer).
5407: **
5408: ** The xMutexInit() method must be threadsafe. ^It must be harmless to
5409: ** invoke xMutexInit() multiple times within the same process and without
5410: ** intervening calls to xMutexEnd(). Second and subsequent calls to
5411: ** xMutexInit() must be no-ops.
5412: **
5413: ** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
5414: ** and its associates). ^Similarly, xMutexAlloc() must not use SQLite memory
5415: ** allocation for a static mutex. ^However xMutexAlloc() may use SQLite
5416: ** memory allocation for a fast or recursive mutex.
5417: **
5418: ** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
5419: ** called, but only if the prior call to xMutexInit returned SQLITE_OK.
5420: ** If xMutexInit fails in any way, it is expected to clean up after itself
5421: ** prior to returning.
5422: */
5423: typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
5424: struct sqlite3_mutex_methods {
5425: int (*xMutexInit)(void);
5426: int (*xMutexEnd)(void);
5427: sqlite3_mutex *(*xMutexAlloc)(int);
5428: void (*xMutexFree)(sqlite3_mutex *);
5429: void (*xMutexEnter)(sqlite3_mutex *);
5430: int (*xMutexTry)(sqlite3_mutex *);
5431: void (*xMutexLeave)(sqlite3_mutex *);
5432: int (*xMutexHeld)(sqlite3_mutex *);
5433: int (*xMutexNotheld)(sqlite3_mutex *);
5434: };
5435:
5436: /*
5437: ** CAPI3REF: Mutex Verification Routines
5438: **
5439: ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
5440: ** are intended for use inside assert() statements. ^The SQLite core
5441: ** never uses these routines except inside an assert() and applications
5442: ** are advised to follow the lead of the core. ^The SQLite core only
5443: ** provides implementations for these routines when it is compiled
5444: ** with the SQLITE_DEBUG flag. ^External mutex implementations
5445: ** are only required to provide these routines if SQLITE_DEBUG is
5446: ** defined and if NDEBUG is not defined.
5447: **
5448: ** ^These routines should return true if the mutex in their argument
5449: ** is held or not held, respectively, by the calling thread.
5450: **
5451: ** ^The implementation is not required to provided versions of these
5452: ** routines that actually work. If the implementation does not provide working
5453: ** versions of these routines, it should at least provide stubs that always
5454: ** return true so that one does not get spurious assertion failures.
5455: **
5456: ** ^If the argument to sqlite3_mutex_held() is a NULL pointer then
5457: ** the routine should return 1. This seems counter-intuitive since
5458: ** clearly the mutex cannot be held if it does not exist. But
5459: ** the reason the mutex does not exist is because the build is not
5460: ** using mutexes. And we do not want the assert() containing the
5461: ** call to sqlite3_mutex_held() to fail, so a non-zero return is
5462: ** the appropriate thing to do. ^The sqlite3_mutex_notheld()
5463: ** interface should also return 1 when given a NULL pointer.
5464: */
5465: #ifndef NDEBUG
5466: SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*);
5467: SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*);
5468: #endif
5469:
5470: /*
5471: ** CAPI3REF: Mutex Types
5472: **
5473: ** The [sqlite3_mutex_alloc()] interface takes a single argument
5474: ** which is one of these integer constants.
5475: **
5476: ** The set of static mutexes may change from one SQLite release to the
5477: ** next. Applications that override the built-in mutex logic must be
5478: ** prepared to accommodate additional static mutexes.
5479: */
5480: #define SQLITE_MUTEX_FAST 0
5481: #define SQLITE_MUTEX_RECURSIVE 1
5482: #define SQLITE_MUTEX_STATIC_MASTER 2
5483: #define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */
5484: #define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */
5485: #define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */
5486: #define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */
5487: #define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */
5488: #define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */
5489: #define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */
5490:
5491: /*
5492: ** CAPI3REF: Retrieve the mutex for a database connection
5493: **
5494: ** ^This interface returns a pointer the [sqlite3_mutex] object that
5495: ** serializes access to the [database connection] given in the argument
5496: ** when the [threading mode] is Serialized.
5497: ** ^If the [threading mode] is Single-thread or Multi-thread then this
5498: ** routine returns a NULL pointer.
5499: */
5500: SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
5501:
5502: /*
5503: ** CAPI3REF: Low-Level Control Of Database Files
5504: **
5505: ** ^The [sqlite3_file_control()] interface makes a direct call to the
5506: ** xFileControl method for the [sqlite3_io_methods] object associated
5507: ** with a particular database identified by the second argument. ^The
5508: ** name of the database is "main" for the main database or "temp" for the
5509: ** TEMP database, or the name that appears after the AS keyword for
5510: ** databases that are added using the [ATTACH] SQL command.
5511: ** ^A NULL pointer can be used in place of "main" to refer to the
5512: ** main database file.
5513: ** ^The third and fourth parameters to this routine
5514: ** are passed directly through to the second and third parameters of
5515: ** the xFileControl method. ^The return value of the xFileControl
5516: ** method becomes the return value of this routine.
5517: **
5518: ** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes
5519: ** a pointer to the underlying [sqlite3_file] object to be written into
5520: ** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER
5521: ** case is a short-circuit path which does not actually invoke the
5522: ** underlying sqlite3_io_methods.xFileControl method.
5523: **
5524: ** ^If the second parameter (zDbName) does not match the name of any
5525: ** open database file, then SQLITE_ERROR is returned. ^This error
5526: ** code is not remembered and will not be recalled by [sqlite3_errcode()]
5527: ** or [sqlite3_errmsg()]. The underlying xFileControl method might
5528: ** also return SQLITE_ERROR. There is no way to distinguish between
5529: ** an incorrect zDbName and an SQLITE_ERROR return from the underlying
5530: ** xFileControl method.
5531: **
5532: ** See also: [SQLITE_FCNTL_LOCKSTATE]
5533: */
5534: SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
5535:
5536: /*
5537: ** CAPI3REF: Testing Interface
5538: **
5539: ** ^The sqlite3_test_control() interface is used to read out internal
5540: ** state of SQLite and to inject faults into SQLite for testing
5541: ** purposes. ^The first parameter is an operation code that determines
5542: ** the number, meaning, and operation of all subsequent parameters.
5543: **
5544: ** This interface is not for use by applications. It exists solely
5545: ** for verifying the correct operation of the SQLite library. Depending
5546: ** on how the SQLite library is compiled, this interface might not exist.
5547: **
5548: ** The details of the operation codes, their meanings, the parameters
5549: ** they take, and what they do are all subject to change without notice.
5550: ** Unlike most of the SQLite API, this function is not guaranteed to
5551: ** operate consistently from one release to the next.
5552: */
5553: SQLITE_API int sqlite3_test_control(int op, ...);
5554:
5555: /*
5556: ** CAPI3REF: Testing Interface Operation Codes
5557: **
5558: ** These constants are the valid operation code parameters used
5559: ** as the first argument to [sqlite3_test_control()].
5560: **
5561: ** These parameters and their meanings are subject to change
5562: ** without notice. These values are for testing purposes only.
5563: ** Applications should not use any of these parameters or the
5564: ** [sqlite3_test_control()] interface.
5565: */
5566: #define SQLITE_TESTCTRL_FIRST 5
5567: #define SQLITE_TESTCTRL_PRNG_SAVE 5
5568: #define SQLITE_TESTCTRL_PRNG_RESTORE 6
5569: #define SQLITE_TESTCTRL_PRNG_RESET 7
5570: #define SQLITE_TESTCTRL_BITVEC_TEST 8
5571: #define SQLITE_TESTCTRL_FAULT_INSTALL 9
5572: #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10
5573: #define SQLITE_TESTCTRL_PENDING_BYTE 11
5574: #define SQLITE_TESTCTRL_ASSERT 12
5575: #define SQLITE_TESTCTRL_ALWAYS 13
5576: #define SQLITE_TESTCTRL_RESERVE 14
5577: #define SQLITE_TESTCTRL_OPTIMIZATIONS 15
5578: #define SQLITE_TESTCTRL_ISKEYWORD 16
5579: #define SQLITE_TESTCTRL_PGHDRSZ 17
5580: #define SQLITE_TESTCTRL_SCRATCHMALLOC 18
5581: #define SQLITE_TESTCTRL_LOCALTIME_FAULT 19
5582: #define SQLITE_TESTCTRL_LAST 19
5583:
5584: /*
5585: ** CAPI3REF: SQLite Runtime Status
5586: **
5587: ** ^This interface is used to retrieve runtime status information
5588: ** about the performance of SQLite, and optionally to reset various
5589: ** highwater marks. ^The first argument is an integer code for
5590: ** the specific parameter to measure. ^(Recognized integer codes
5591: ** are of the form [status parameters | SQLITE_STATUS_...].)^
5592: ** ^The current value of the parameter is returned into *pCurrent.
5593: ** ^The highest recorded value is returned in *pHighwater. ^If the
5594: ** resetFlag is true, then the highest record value is reset after
5595: ** *pHighwater is written. ^(Some parameters do not record the highest
5596: ** value. For those parameters
5597: ** nothing is written into *pHighwater and the resetFlag is ignored.)^
5598: ** ^(Other parameters record only the highwater mark and not the current
5599: ** value. For these latter parameters nothing is written into *pCurrent.)^
5600: **
5601: ** ^The sqlite3_status() routine returns SQLITE_OK on success and a
5602: ** non-zero [error code] on failure.
5603: **
5604: ** This routine is threadsafe but is not atomic. This routine can be
5605: ** called while other threads are running the same or different SQLite
5606: ** interfaces. However the values returned in *pCurrent and
5607: ** *pHighwater reflect the status of SQLite at different points in time
5608: ** and it is possible that another thread might change the parameter
5609: ** in between the times when *pCurrent and *pHighwater are written.
5610: **
5611: ** See also: [sqlite3_db_status()]
5612: */
5613: SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
5614:
5615:
5616: /*
5617: ** CAPI3REF: Status Parameters
5618: ** KEYWORDS: {status parameters}
5619: **
5620: ** These integer constants designate various run-time status parameters
5621: ** that can be returned by [sqlite3_status()].
5622: **
5623: ** <dl>
5624: ** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
5625: ** <dd>This parameter is the current amount of memory checked out
5626: ** using [sqlite3_malloc()], either directly or indirectly. The
5627: ** figure includes calls made to [sqlite3_malloc()] by the application
5628: ** and internal memory usage by the SQLite library. Scratch memory
5629: ** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache
5630: ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
5631: ** this parameter. The amount returned is the sum of the allocation
5632: ** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
5633: **
5634: ** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
5635: ** <dd>This parameter records the largest memory allocation request
5636: ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
5637: ** internal equivalents). Only the value returned in the
5638: ** *pHighwater parameter to [sqlite3_status()] is of interest.
5639: ** The value written into the *pCurrent parameter is undefined.</dd>)^
5640: **
5641: ** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
5642: ** <dd>This parameter records the number of separate memory allocations
5643: ** currently checked out.</dd>)^
5644: **
5645: ** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
5646: ** <dd>This parameter returns the number of pages used out of the
5647: ** [pagecache memory allocator] that was configured using
5648: ** [SQLITE_CONFIG_PAGECACHE]. The
5649: ** value returned is in pages, not in bytes.</dd>)^
5650: **
5651: ** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]]
5652: ** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
5653: ** <dd>This parameter returns the number of bytes of page cache
5654: ** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
5655: ** buffer and where forced to overflow to [sqlite3_malloc()]. The
5656: ** returned value includes allocations that overflowed because they
5657: ** where too large (they were larger than the "sz" parameter to
5658: ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
5659: ** no space was left in the page cache.</dd>)^
5660: **
5661: ** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
5662: ** <dd>This parameter records the largest memory allocation request
5663: ** handed to [pagecache memory allocator]. Only the value returned in the
5664: ** *pHighwater parameter to [sqlite3_status()] is of interest.
5665: ** The value written into the *pCurrent parameter is undefined.</dd>)^
5666: **
5667: ** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt>
5668: ** <dd>This parameter returns the number of allocations used out of the
5669: ** [scratch memory allocator] configured using
5670: ** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not
5671: ** in bytes. Since a single thread may only have one scratch allocation
5672: ** outstanding at time, this parameter also reports the number of threads
5673: ** using scratch memory at the same time.</dd>)^
5674: **
5675: ** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
5676: ** <dd>This parameter returns the number of bytes of scratch memory
5677: ** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH]
5678: ** buffer and where forced to overflow to [sqlite3_malloc()]. The values
5679: ** returned include overflows because the requested allocation was too
5680: ** larger (that is, because the requested allocation was larger than the
5681: ** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer
5682: ** slots were available.
5683: ** </dd>)^
5684: **
5685: ** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
5686: ** <dd>This parameter records the largest memory allocation request
5687: ** handed to [scratch memory allocator]. Only the value returned in the
5688: ** *pHighwater parameter to [sqlite3_status()] is of interest.
5689: ** The value written into the *pCurrent parameter is undefined.</dd>)^
5690: **
5691: ** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
5692: ** <dd>This parameter records the deepest parser stack. It is only
5693: ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
5694: ** </dl>
5695: **
5696: ** New status parameters may be added from time to time.
5697: */
5698: #define SQLITE_STATUS_MEMORY_USED 0
5699: #define SQLITE_STATUS_PAGECACHE_USED 1
5700: #define SQLITE_STATUS_PAGECACHE_OVERFLOW 2
5701: #define SQLITE_STATUS_SCRATCH_USED 3
5702: #define SQLITE_STATUS_SCRATCH_OVERFLOW 4
5703: #define SQLITE_STATUS_MALLOC_SIZE 5
5704: #define SQLITE_STATUS_PARSER_STACK 6
5705: #define SQLITE_STATUS_PAGECACHE_SIZE 7
5706: #define SQLITE_STATUS_SCRATCH_SIZE 8
5707: #define SQLITE_STATUS_MALLOC_COUNT 9
5708:
5709: /*
5710: ** CAPI3REF: Database Connection Status
5711: **
5712: ** ^This interface is used to retrieve runtime status information
5713: ** about a single [database connection]. ^The first argument is the
5714: ** database connection object to be interrogated. ^The second argument
5715: ** is an integer constant, taken from the set of
5716: ** [SQLITE_DBSTATUS options], that
5717: ** determines the parameter to interrogate. The set of
5718: ** [SQLITE_DBSTATUS options] is likely
5719: ** to grow in future releases of SQLite.
5720: **
5721: ** ^The current value of the requested parameter is written into *pCur
5722: ** and the highest instantaneous value is written into *pHiwtr. ^If
5723: ** the resetFlg is true, then the highest instantaneous value is
5724: ** reset back down to the current value.
5725: **
5726: ** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
5727: ** non-zero [error code] on failure.
5728: **
5729: ** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
5730: */
5731: SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
5732:
5733: /*
5734: ** CAPI3REF: Status Parameters for database connections
5735: ** KEYWORDS: {SQLITE_DBSTATUS options}
5736: **
5737: ** These constants are the available integer "verbs" that can be passed as
5738: ** the second argument to the [sqlite3_db_status()] interface.
5739: **
5740: ** New verbs may be added in future releases of SQLite. Existing verbs
5741: ** might be discontinued. Applications should check the return code from
5742: ** [sqlite3_db_status()] to make sure that the call worked.
5743: ** The [sqlite3_db_status()] interface will return a non-zero error code
5744: ** if a discontinued or unsupported verb is invoked.
5745: **
5746: ** <dl>
5747: ** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
5748: ** <dd>This parameter returns the number of lookaside memory slots currently
5749: ** checked out.</dd>)^
5750: **
5751: ** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
5752: ** <dd>This parameter returns the number malloc attempts that were
5753: ** satisfied using lookaside memory. Only the high-water value is meaningful;
5754: ** the current value is always zero.)^
5755: **
5756: ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]]
5757: ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
5758: ** <dd>This parameter returns the number malloc attempts that might have
5759: ** been satisfied using lookaside memory but failed due to the amount of
5760: ** memory requested being larger than the lookaside slot size.
5761: ** Only the high-water value is meaningful;
5762: ** the current value is always zero.)^
5763: **
5764: ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]]
5765: ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
5766: ** <dd>This parameter returns the number malloc attempts that might have
5767: ** been satisfied using lookaside memory but failed due to all lookaside
5768: ** memory already being in use.
5769: ** Only the high-water value is meaningful;
5770: ** the current value is always zero.)^
5771: **
5772: ** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
5773: ** <dd>This parameter returns the approximate number of of bytes of heap
5774: ** memory used by all pager caches associated with the database connection.)^
5775: ** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
5776: **
5777: ** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
5778: ** <dd>This parameter returns the approximate number of of bytes of heap
5779: ** memory used to store the schema for all databases associated
5780: ** with the connection - main, temp, and any [ATTACH]-ed databases.)^
5781: ** ^The full amount of memory used by the schemas is reported, even if the
5782: ** schema memory is shared with other database connections due to
5783: ** [shared cache mode] being enabled.
5784: ** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
5785: **
5786: ** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
5787: ** <dd>This parameter returns the approximate number of of bytes of heap
5788: ** and lookaside memory used by all prepared statements associated with
5789: ** the database connection.)^
5790: ** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
5791: ** </dd>
5792: ** </dl>
5793: */
5794: #define SQLITE_DBSTATUS_LOOKASIDE_USED 0
5795: #define SQLITE_DBSTATUS_CACHE_USED 1
5796: #define SQLITE_DBSTATUS_SCHEMA_USED 2
5797: #define SQLITE_DBSTATUS_STMT_USED 3
5798: #define SQLITE_DBSTATUS_LOOKASIDE_HIT 4
5799: #define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5
5800: #define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6
5801: #define SQLITE_DBSTATUS_MAX 6 /* Largest defined DBSTATUS */
5802:
5803:
5804: /*
5805: ** CAPI3REF: Prepared Statement Status
5806: **
5807: ** ^(Each prepared statement maintains various
5808: ** [SQLITE_STMTSTATUS counters] that measure the number
5809: ** of times it has performed specific operations.)^ These counters can
5810: ** be used to monitor the performance characteristics of the prepared
5811: ** statements. For example, if the number of table steps greatly exceeds
5812: ** the number of table searches or result rows, that would tend to indicate
5813: ** that the prepared statement is using a full table scan rather than
5814: ** an index.
5815: **
5816: ** ^(This interface is used to retrieve and reset counter values from
5817: ** a [prepared statement]. The first argument is the prepared statement
5818: ** object to be interrogated. The second argument
5819: ** is an integer code for a specific [SQLITE_STMTSTATUS counter]
5820: ** to be interrogated.)^
5821: ** ^The current value of the requested counter is returned.
5822: ** ^If the resetFlg is true, then the counter is reset to zero after this
5823: ** interface call returns.
5824: **
5825: ** See also: [sqlite3_status()] and [sqlite3_db_status()].
5826: */
5827: SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
5828:
5829: /*
5830: ** CAPI3REF: Status Parameters for prepared statements
5831: ** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters}
5832: **
5833: ** These preprocessor macros define integer codes that name counter
5834: ** values associated with the [sqlite3_stmt_status()] interface.
5835: ** The meanings of the various counters are as follows:
5836: **
5837: ** <dl>
5838: ** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
5839: ** <dd>^This is the number of times that SQLite has stepped forward in
5840: ** a table as part of a full table scan. Large numbers for this counter
5841: ** may indicate opportunities for performance improvement through
5842: ** careful use of indices.</dd>
5843: **
5844: ** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt>
5845: ** <dd>^This is the number of sort operations that have occurred.
5846: ** A non-zero value in this counter may indicate an opportunity to
5847: ** improvement performance through careful use of indices.</dd>
5848: **
5849: ** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
5850: ** <dd>^This is the number of rows inserted into transient indices that
5851: ** were created automatically in order to help joins run faster.
5852: ** A non-zero value in this counter may indicate an opportunity to
5853: ** improvement performance by adding permanent indices that do not
5854: ** need to be reinitialized each time the statement is run.</dd>
5855: **
5856: ** </dl>
5857: */
5858: #define SQLITE_STMTSTATUS_FULLSCAN_STEP 1
5859: #define SQLITE_STMTSTATUS_SORT 2
5860: #define SQLITE_STMTSTATUS_AUTOINDEX 3
5861:
5862: /*
5863: ** CAPI3REF: Custom Page Cache Object
5864: **
5865: ** The sqlite3_pcache type is opaque. It is implemented by
5866: ** the pluggable module. The SQLite core has no knowledge of
5867: ** its size or internal structure and never deals with the
5868: ** sqlite3_pcache object except by holding and passing pointers
5869: ** to the object.
5870: **
5871: ** See [sqlite3_pcache_methods] for additional information.
5872: */
5873: typedef struct sqlite3_pcache sqlite3_pcache;
5874:
5875: /*
5876: ** CAPI3REF: Application Defined Page Cache.
5877: ** KEYWORDS: {page cache}
5878: **
5879: ** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE], ...) interface can
5880: ** register an alternative page cache implementation by passing in an
5881: ** instance of the sqlite3_pcache_methods structure.)^
5882: ** In many applications, most of the heap memory allocated by
5883: ** SQLite is used for the page cache.
5884: ** By implementing a
5885: ** custom page cache using this API, an application can better control
5886: ** the amount of memory consumed by SQLite, the way in which
5887: ** that memory is allocated and released, and the policies used to
5888: ** determine exactly which parts of a database file are cached and for
5889: ** how long.
5890: **
5891: ** The alternative page cache mechanism is an
5892: ** extreme measure that is only needed by the most demanding applications.
5893: ** The built-in page cache is recommended for most uses.
5894: **
5895: ** ^(The contents of the sqlite3_pcache_methods structure are copied to an
5896: ** internal buffer by SQLite within the call to [sqlite3_config]. Hence
5897: ** the application may discard the parameter after the call to
5898: ** [sqlite3_config()] returns.)^
5899: **
5900: ** [[the xInit() page cache method]]
5901: ** ^(The xInit() method is called once for each effective
5902: ** call to [sqlite3_initialize()])^
5903: ** (usually only once during the lifetime of the process). ^(The xInit()
5904: ** method is passed a copy of the sqlite3_pcache_methods.pArg value.)^
5905: ** The intent of the xInit() method is to set up global data structures
5906: ** required by the custom page cache implementation.
5907: ** ^(If the xInit() method is NULL, then the
5908: ** built-in default page cache is used instead of the application defined
5909: ** page cache.)^
5910: **
5911: ** [[the xShutdown() page cache method]]
5912: ** ^The xShutdown() method is called by [sqlite3_shutdown()].
5913: ** It can be used to clean up
5914: ** any outstanding resources before process shutdown, if required.
5915: ** ^The xShutdown() method may be NULL.
5916: **
5917: ** ^SQLite automatically serializes calls to the xInit method,
5918: ** so the xInit method need not be threadsafe. ^The
5919: ** xShutdown method is only called from [sqlite3_shutdown()] so it does
5920: ** not need to be threadsafe either. All other methods must be threadsafe
5921: ** in multithreaded applications.
5922: **
5923: ** ^SQLite will never invoke xInit() more than once without an intervening
5924: ** call to xShutdown().
5925: **
5926: ** [[the xCreate() page cache methods]]
5927: ** ^SQLite invokes the xCreate() method to construct a new cache instance.
5928: ** SQLite will typically create one cache instance for each open database file,
5929: ** though this is not guaranteed. ^The
5930: ** first parameter, szPage, is the size in bytes of the pages that must
5931: ** be allocated by the cache. ^szPage will not be a power of two. ^szPage
5932: ** will the page size of the database file that is to be cached plus an
5933: ** increment (here called "R") of less than 250. SQLite will use the
5934: ** extra R bytes on each page to store metadata about the underlying
5935: ** database page on disk. The value of R depends
5936: ** on the SQLite version, the target platform, and how SQLite was compiled.
5937: ** ^(R is constant for a particular build of SQLite. Except, there are two
5938: ** distinct values of R when SQLite is compiled with the proprietary
5939: ** ZIPVFS extension.)^ ^The second argument to
5940: ** xCreate(), bPurgeable, is true if the cache being created will
5941: ** be used to cache database pages of a file stored on disk, or
5942: ** false if it is used for an in-memory database. The cache implementation
5943: ** does not have to do anything special based with the value of bPurgeable;
5944: ** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will
5945: ** never invoke xUnpin() except to deliberately delete a page.
5946: ** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
5947: ** false will always have the "discard" flag set to true.
5948: ** ^Hence, a cache created with bPurgeable false will
5949: ** never contain any unpinned pages.
5950: **
5951: ** [[the xCachesize() page cache method]]
5952: ** ^(The xCachesize() method may be called at any time by SQLite to set the
5953: ** suggested maximum cache-size (number of pages stored by) the cache
5954: ** instance passed as the first argument. This is the value configured using
5955: ** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable
5956: ** parameter, the implementation is not required to do anything with this
5957: ** value; it is advisory only.
5958: **
5959: ** [[the xPagecount() page cache methods]]
5960: ** The xPagecount() method must return the number of pages currently
5961: ** stored in the cache, both pinned and unpinned.
5962: **
5963: ** [[the xFetch() page cache methods]]
5964: ** The xFetch() method locates a page in the cache and returns a pointer to
5965: ** the page, or a NULL pointer.
5966: ** A "page", in this context, means a buffer of szPage bytes aligned at an
5967: ** 8-byte boundary. The page to be fetched is determined by the key. ^The
5968: ** minimum key value is 1. After it has been retrieved using xFetch, the page
5969: ** is considered to be "pinned".
5970: **
5971: ** If the requested page is already in the page cache, then the page cache
5972: ** implementation must return a pointer to the page buffer with its content
5973: ** intact. If the requested page is not already in the cache, then the
5974: ** cache implementation should use the value of the createFlag
5975: ** parameter to help it determined what action to take:
5976: **
5977: ** <table border=1 width=85% align=center>
5978: ** <tr><th> createFlag <th> Behaviour when page is not already in cache
5979: ** <tr><td> 0 <td> Do not allocate a new page. Return NULL.
5980: ** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
5981: ** Otherwise return NULL.
5982: ** <tr><td> 2 <td> Make every effort to allocate a new page. Only return
5983: ** NULL if allocating a new page is effectively impossible.
5984: ** </table>
5985: **
5986: ** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite
5987: ** will only use a createFlag of 2 after a prior call with a createFlag of 1
5988: ** failed.)^ In between the to xFetch() calls, SQLite may
5989: ** attempt to unpin one or more cache pages by spilling the content of
5990: ** pinned pages to disk and synching the operating system disk cache.
5991: **
5992: ** [[the xUnpin() page cache method]]
5993: ** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
5994: ** as its second argument. If the third parameter, discard, is non-zero,
5995: ** then the page must be evicted from the cache.
5996: ** ^If the discard parameter is
5997: ** zero, then the page may be discarded or retained at the discretion of
5998: ** page cache implementation. ^The page cache implementation
5999: ** may choose to evict unpinned pages at any time.
6000: **
6001: ** The cache must not perform any reference counting. A single
6002: ** call to xUnpin() unpins the page regardless of the number of prior calls
6003: ** to xFetch().
6004: **
6005: ** [[the xRekey() page cache methods]]
6006: ** The xRekey() method is used to change the key value associated with the
6007: ** page passed as the second argument. If the cache
6008: ** previously contains an entry associated with newKey, it must be
6009: ** discarded. ^Any prior cache entry associated with newKey is guaranteed not
6010: ** to be pinned.
6011: **
6012: ** When SQLite calls the xTruncate() method, the cache must discard all
6013: ** existing cache entries with page numbers (keys) greater than or equal
6014: ** to the value of the iLimit parameter passed to xTruncate(). If any
6015: ** of these pages are pinned, they are implicitly unpinned, meaning that
6016: ** they can be safely discarded.
6017: **
6018: ** [[the xDestroy() page cache method]]
6019: ** ^The xDestroy() method is used to delete a cache allocated by xCreate().
6020: ** All resources associated with the specified cache should be freed. ^After
6021: ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
6022: ** handle invalid, and will not use it with any other sqlite3_pcache_methods
6023: ** functions.
6024: */
6025: typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
6026: struct sqlite3_pcache_methods {
6027: void *pArg;
6028: int (*xInit)(void*);
6029: void (*xShutdown)(void*);
6030: sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
6031: void (*xCachesize)(sqlite3_pcache*, int nCachesize);
6032: int (*xPagecount)(sqlite3_pcache*);
6033: void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
6034: void (*xUnpin)(sqlite3_pcache*, void*, int discard);
6035: void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
6036: void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
6037: void (*xDestroy)(sqlite3_pcache*);
6038: };
6039:
6040: /*
6041: ** CAPI3REF: Online Backup Object
6042: **
6043: ** The sqlite3_backup object records state information about an ongoing
6044: ** online backup operation. ^The sqlite3_backup object is created by
6045: ** a call to [sqlite3_backup_init()] and is destroyed by a call to
6046: ** [sqlite3_backup_finish()].
6047: **
6048: ** See Also: [Using the SQLite Online Backup API]
6049: */
6050: typedef struct sqlite3_backup sqlite3_backup;
6051:
6052: /*
6053: ** CAPI3REF: Online Backup API.
6054: **
6055: ** The backup API copies the content of one database into another.
6056: ** It is useful either for creating backups of databases or
6057: ** for copying in-memory databases to or from persistent files.
6058: **
6059: ** See Also: [Using the SQLite Online Backup API]
6060: **
6061: ** ^SQLite holds a write transaction open on the destination database file
6062: ** for the duration of the backup operation.
6063: ** ^The source database is read-locked only while it is being read;
6064: ** it is not locked continuously for the entire backup operation.
6065: ** ^Thus, the backup may be performed on a live source database without
6066: ** preventing other database connections from
6067: ** reading or writing to the source database while the backup is underway.
6068: **
6069: ** ^(To perform a backup operation:
6070: ** <ol>
6071: ** <li><b>sqlite3_backup_init()</b> is called once to initialize the
6072: ** backup,
6073: ** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
6074: ** the data between the two databases, and finally
6075: ** <li><b>sqlite3_backup_finish()</b> is called to release all resources
6076: ** associated with the backup operation.
6077: ** </ol>)^
6078: ** There should be exactly one call to sqlite3_backup_finish() for each
6079: ** successful call to sqlite3_backup_init().
6080: **
6081: ** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
6082: **
6083: ** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
6084: ** [database connection] associated with the destination database
6085: ** and the database name, respectively.
6086: ** ^The database name is "main" for the main database, "temp" for the
6087: ** temporary database, or the name specified after the AS keyword in
6088: ** an [ATTACH] statement for an attached database.
6089: ** ^The S and M arguments passed to
6090: ** sqlite3_backup_init(D,N,S,M) identify the [database connection]
6091: ** and database name of the source database, respectively.
6092: ** ^The source and destination [database connections] (parameters S and D)
6093: ** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
6094: ** an error.
6095: **
6096: ** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
6097: ** returned and an error code and error message are stored in the
6098: ** destination [database connection] D.
6099: ** ^The error code and message for the failed call to sqlite3_backup_init()
6100: ** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
6101: ** [sqlite3_errmsg16()] functions.
6102: ** ^A successful call to sqlite3_backup_init() returns a pointer to an
6103: ** [sqlite3_backup] object.
6104: ** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
6105: ** sqlite3_backup_finish() functions to perform the specified backup
6106: ** operation.
6107: **
6108: ** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
6109: **
6110: ** ^Function sqlite3_backup_step(B,N) will copy up to N pages between
6111: ** the source and destination databases specified by [sqlite3_backup] object B.
6112: ** ^If N is negative, all remaining source pages are copied.
6113: ** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
6114: ** are still more pages to be copied, then the function returns [SQLITE_OK].
6115: ** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
6116: ** from source to destination, then it returns [SQLITE_DONE].
6117: ** ^If an error occurs while running sqlite3_backup_step(B,N),
6118: ** then an [error code] is returned. ^As well as [SQLITE_OK] and
6119: ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
6120: ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
6121: ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
6122: **
6123: ** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
6124: ** <ol>
6125: ** <li> the destination database was opened read-only, or
6126: ** <li> the destination database is using write-ahead-log journaling
6127: ** and the destination and source page sizes differ, or
6128: ** <li> the destination database is an in-memory database and the
6129: ** destination and source page sizes differ.
6130: ** </ol>)^
6131: **
6132: ** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
6133: ** the [sqlite3_busy_handler | busy-handler function]
6134: ** is invoked (if one is specified). ^If the
6135: ** busy-handler returns non-zero before the lock is available, then
6136: ** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
6137: ** sqlite3_backup_step() can be retried later. ^If the source
6138: ** [database connection]
6139: ** is being used to write to the source database when sqlite3_backup_step()
6140: ** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
6141: ** case the call to sqlite3_backup_step() can be retried later on. ^(If
6142: ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
6143: ** [SQLITE_READONLY] is returned, then
6144: ** there is no point in retrying the call to sqlite3_backup_step(). These
6145: ** errors are considered fatal.)^ The application must accept
6146: ** that the backup operation has failed and pass the backup operation handle
6147: ** to the sqlite3_backup_finish() to release associated resources.
6148: **
6149: ** ^The first call to sqlite3_backup_step() obtains an exclusive lock
6150: ** on the destination file. ^The exclusive lock is not released until either
6151: ** sqlite3_backup_finish() is called or the backup operation is complete
6152: ** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to
6153: ** sqlite3_backup_step() obtains a [shared lock] on the source database that
6154: ** lasts for the duration of the sqlite3_backup_step() call.
6155: ** ^Because the source database is not locked between calls to
6156: ** sqlite3_backup_step(), the source database may be modified mid-way
6157: ** through the backup process. ^If the source database is modified by an
6158: ** external process or via a database connection other than the one being
6159: ** used by the backup operation, then the backup will be automatically
6160: ** restarted by the next call to sqlite3_backup_step(). ^If the source
6161: ** database is modified by the using the same database connection as is used
6162: ** by the backup operation, then the backup database is automatically
6163: ** updated at the same time.
6164: **
6165: ** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
6166: **
6167: ** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the
6168: ** application wishes to abandon the backup operation, the application
6169: ** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
6170: ** ^The sqlite3_backup_finish() interfaces releases all
6171: ** resources associated with the [sqlite3_backup] object.
6172: ** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
6173: ** active write-transaction on the destination database is rolled back.
6174: ** The [sqlite3_backup] object is invalid
6175: ** and may not be used following a call to sqlite3_backup_finish().
6176: **
6177: ** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
6178: ** sqlite3_backup_step() errors occurred, regardless or whether or not
6179: ** sqlite3_backup_step() completed.
6180: ** ^If an out-of-memory condition or IO error occurred during any prior
6181: ** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
6182: ** sqlite3_backup_finish() returns the corresponding [error code].
6183: **
6184: ** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
6185: ** is not a permanent error and does not affect the return value of
6186: ** sqlite3_backup_finish().
6187: **
6188: ** [[sqlite3_backup__remaining()]] [[sqlite3_backup_pagecount()]]
6189: ** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
6190: **
6191: ** ^Each call to sqlite3_backup_step() sets two values inside
6192: ** the [sqlite3_backup] object: the number of pages still to be backed
6193: ** up and the total number of pages in the source database file.
6194: ** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces
6195: ** retrieve these two values, respectively.
6196: **
6197: ** ^The values returned by these functions are only updated by
6198: ** sqlite3_backup_step(). ^If the source database is modified during a backup
6199: ** operation, then the values are not updated to account for any extra
6200: ** pages that need to be updated or the size of the source database file
6201: ** changing.
6202: **
6203: ** <b>Concurrent Usage of Database Handles</b>
6204: **
6205: ** ^The source [database connection] may be used by the application for other
6206: ** purposes while a backup operation is underway or being initialized.
6207: ** ^If SQLite is compiled and configured to support threadsafe database
6208: ** connections, then the source database connection may be used concurrently
6209: ** from within other threads.
6210: **
6211: ** However, the application must guarantee that the destination
6212: ** [database connection] is not passed to any other API (by any thread) after
6213: ** sqlite3_backup_init() is called and before the corresponding call to
6214: ** sqlite3_backup_finish(). SQLite does not currently check to see
6215: ** if the application incorrectly accesses the destination [database connection]
6216: ** and so no error code is reported, but the operations may malfunction
6217: ** nevertheless. Use of the destination database connection while a
6218: ** backup is in progress might also also cause a mutex deadlock.
6219: **
6220: ** If running in [shared cache mode], the application must
6221: ** guarantee that the shared cache used by the destination database
6222: ** is not accessed while the backup is running. In practice this means
6223: ** that the application must guarantee that the disk file being
6224: ** backed up to is not accessed by any connection within the process,
6225: ** not just the specific connection that was passed to sqlite3_backup_init().
6226: **
6227: ** The [sqlite3_backup] object itself is partially threadsafe. Multiple
6228: ** threads may safely make multiple concurrent calls to sqlite3_backup_step().
6229: ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
6230: ** APIs are not strictly speaking threadsafe. If they are invoked at the
6231: ** same time as another thread is invoking sqlite3_backup_step() it is
6232: ** possible that they return invalid values.
6233: */
6234: SQLITE_API sqlite3_backup *sqlite3_backup_init(
6235: sqlite3 *pDest, /* Destination database handle */
6236: const char *zDestName, /* Destination database name */
6237: sqlite3 *pSource, /* Source database handle */
6238: const char *zSourceName /* Source database name */
6239: );
6240: SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage);
6241: SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p);
6242: SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p);
6243: SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p);
6244:
6245: /*
6246: ** CAPI3REF: Unlock Notification
6247: **
6248: ** ^When running in shared-cache mode, a database operation may fail with
6249: ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
6250: ** individual tables within the shared-cache cannot be obtained. See
6251: ** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
6252: ** ^This API may be used to register a callback that SQLite will invoke
6253: ** when the connection currently holding the required lock relinquishes it.
6254: ** ^This API is only available if the library was compiled with the
6255: ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
6256: **
6257: ** See Also: [Using the SQLite Unlock Notification Feature].
6258: **
6259: ** ^Shared-cache locks are released when a database connection concludes
6260: ** its current transaction, either by committing it or rolling it back.
6261: **
6262: ** ^When a connection (known as the blocked connection) fails to obtain a
6263: ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
6264: ** identity of the database connection (the blocking connection) that
6265: ** has locked the required resource is stored internally. ^After an
6266: ** application receives an SQLITE_LOCKED error, it may call the
6267: ** sqlite3_unlock_notify() method with the blocked connection handle as
6268: ** the first argument to register for a callback that will be invoked
6269: ** when the blocking connections current transaction is concluded. ^The
6270: ** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
6271: ** call that concludes the blocking connections transaction.
6272: **
6273: ** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
6274: ** there is a chance that the blocking connection will have already
6275: ** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
6276: ** If this happens, then the specified callback is invoked immediately,
6277: ** from within the call to sqlite3_unlock_notify().)^
6278: **
6279: ** ^If the blocked connection is attempting to obtain a write-lock on a
6280: ** shared-cache table, and more than one other connection currently holds
6281: ** a read-lock on the same table, then SQLite arbitrarily selects one of
6282: ** the other connections to use as the blocking connection.
6283: **
6284: ** ^(There may be at most one unlock-notify callback registered by a
6285: ** blocked connection. If sqlite3_unlock_notify() is called when the
6286: ** blocked connection already has a registered unlock-notify callback,
6287: ** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
6288: ** called with a NULL pointer as its second argument, then any existing
6289: ** unlock-notify callback is canceled. ^The blocked connections
6290: ** unlock-notify callback may also be canceled by closing the blocked
6291: ** connection using [sqlite3_close()].
6292: **
6293: ** The unlock-notify callback is not reentrant. If an application invokes
6294: ** any sqlite3_xxx API functions from within an unlock-notify callback, a
6295: ** crash or deadlock may be the result.
6296: **
6297: ** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
6298: ** returns SQLITE_OK.
6299: **
6300: ** <b>Callback Invocation Details</b>
6301: **
6302: ** When an unlock-notify callback is registered, the application provides a
6303: ** single void* pointer that is passed to the callback when it is invoked.
6304: ** However, the signature of the callback function allows SQLite to pass
6305: ** it an array of void* context pointers. The first argument passed to
6306: ** an unlock-notify callback is a pointer to an array of void* pointers,
6307: ** and the second is the number of entries in the array.
6308: **
6309: ** When a blocking connections transaction is concluded, there may be
6310: ** more than one blocked connection that has registered for an unlock-notify
6311: ** callback. ^If two or more such blocked connections have specified the
6312: ** same callback function, then instead of invoking the callback function
6313: ** multiple times, it is invoked once with the set of void* context pointers
6314: ** specified by the blocked connections bundled together into an array.
6315: ** This gives the application an opportunity to prioritize any actions
6316: ** related to the set of unblocked database connections.
6317: **
6318: ** <b>Deadlock Detection</b>
6319: **
6320: ** Assuming that after registering for an unlock-notify callback a
6321: ** database waits for the callback to be issued before taking any further
6322: ** action (a reasonable assumption), then using this API may cause the
6323: ** application to deadlock. For example, if connection X is waiting for
6324: ** connection Y's transaction to be concluded, and similarly connection
6325: ** Y is waiting on connection X's transaction, then neither connection
6326: ** will proceed and the system may remain deadlocked indefinitely.
6327: **
6328: ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
6329: ** detection. ^If a given call to sqlite3_unlock_notify() would put the
6330: ** system in a deadlocked state, then SQLITE_LOCKED is returned and no
6331: ** unlock-notify callback is registered. The system is said to be in
6332: ** a deadlocked state if connection A has registered for an unlock-notify
6333: ** callback on the conclusion of connection B's transaction, and connection
6334: ** B has itself registered for an unlock-notify callback when connection
6335: ** A's transaction is concluded. ^Indirect deadlock is also detected, so
6336: ** the system is also considered to be deadlocked if connection B has
6337: ** registered for an unlock-notify callback on the conclusion of connection
6338: ** C's transaction, where connection C is waiting on connection A. ^Any
6339: ** number of levels of indirection are allowed.
6340: **
6341: ** <b>The "DROP TABLE" Exception</b>
6342: **
6343: ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost
6344: ** always appropriate to call sqlite3_unlock_notify(). There is however,
6345: ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
6346: ** SQLite checks if there are any currently executing SELECT statements
6347: ** that belong to the same connection. If there are, SQLITE_LOCKED is
6348: ** returned. In this case there is no "blocking connection", so invoking
6349: ** sqlite3_unlock_notify() results in the unlock-notify callback being
6350: ** invoked immediately. If the application then re-attempts the "DROP TABLE"
6351: ** or "DROP INDEX" query, an infinite loop might be the result.
6352: **
6353: ** One way around this problem is to check the extended error code returned
6354: ** by an sqlite3_step() call. ^(If there is a blocking connection, then the
6355: ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
6356: ** the special "DROP TABLE/INDEX" case, the extended error code is just
6357: ** SQLITE_LOCKED.)^
6358: */
6359: SQLITE_API int sqlite3_unlock_notify(
6360: sqlite3 *pBlocked, /* Waiting connection */
6361: void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */
6362: void *pNotifyArg /* Argument to pass to xNotify */
6363: );
6364:
6365:
6366: /*
6367: ** CAPI3REF: String Comparison
6368: **
6369: ** ^The [sqlite3_strnicmp()] API allows applications and extensions to
6370: ** compare the contents of two buffers containing UTF-8 strings in a
6371: ** case-independent fashion, using the same definition of case independence
6372: ** that SQLite uses internally when comparing identifiers.
6373: */
6374: SQLITE_API int sqlite3_strnicmp(const char *, const char *, int);
6375:
6376: /*
6377: ** CAPI3REF: Error Logging Interface
6378: **
6379: ** ^The [sqlite3_log()] interface writes a message into the error log
6380: ** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
6381: ** ^If logging is enabled, the zFormat string and subsequent arguments are
6382: ** used with [sqlite3_snprintf()] to generate the final output string.
6383: **
6384: ** The sqlite3_log() interface is intended for use by extensions such as
6385: ** virtual tables, collating functions, and SQL functions. While there is
6386: ** nothing to prevent an application from calling sqlite3_log(), doing so
6387: ** is considered bad form.
6388: **
6389: ** The zFormat string must not be NULL.
6390: **
6391: ** To avoid deadlocks and other threading problems, the sqlite3_log() routine
6392: ** will not use dynamically allocated memory. The log message is stored in
6393: ** a fixed-length buffer on the stack. If the log message is longer than
6394: ** a few hundred characters, it will be truncated to the length of the
6395: ** buffer.
6396: */
6397: SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...);
6398:
6399: /*
6400: ** CAPI3REF: Write-Ahead Log Commit Hook
6401: **
6402: ** ^The [sqlite3_wal_hook()] function is used to register a callback that
6403: ** will be invoked each time a database connection commits data to a
6404: ** [write-ahead log] (i.e. whenever a transaction is committed in
6405: ** [journal_mode | journal_mode=WAL mode]).
6406: **
6407: ** ^The callback is invoked by SQLite after the commit has taken place and
6408: ** the associated write-lock on the database released, so the implementation
6409: ** may read, write or [checkpoint] the database as required.
6410: **
6411: ** ^The first parameter passed to the callback function when it is invoked
6412: ** is a copy of the third parameter passed to sqlite3_wal_hook() when
6413: ** registering the callback. ^The second is a copy of the database handle.
6414: ** ^The third parameter is the name of the database that was written to -
6415: ** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
6416: ** is the number of pages currently in the write-ahead log file,
6417: ** including those that were just committed.
6418: **
6419: ** The callback function should normally return [SQLITE_OK]. ^If an error
6420: ** code is returned, that error will propagate back up through the
6421: ** SQLite code base to cause the statement that provoked the callback
6422: ** to report an error, though the commit will have still occurred. If the
6423: ** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
6424: ** that does not correspond to any valid SQLite error code, the results
6425: ** are undefined.
6426: **
6427: ** A single database handle may have at most a single write-ahead log callback
6428: ** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
6429: ** previously registered write-ahead log callback. ^Note that the
6430: ** [sqlite3_wal_autocheckpoint()] interface and the
6431: ** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
6432: ** those overwrite any prior [sqlite3_wal_hook()] settings.
6433: */
6434: SQLITE_API void *sqlite3_wal_hook(
6435: sqlite3*,
6436: int(*)(void *,sqlite3*,const char*,int),
6437: void*
6438: );
6439:
6440: /*
6441: ** CAPI3REF: Configure an auto-checkpoint
6442: **
6443: ** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
6444: ** [sqlite3_wal_hook()] that causes any database on [database connection] D
6445: ** to automatically [checkpoint]
6446: ** after committing a transaction if there are N or
6447: ** more frames in the [write-ahead log] file. ^Passing zero or
6448: ** a negative value as the nFrame parameter disables automatic
6449: ** checkpoints entirely.
6450: **
6451: ** ^The callback registered by this function replaces any existing callback
6452: ** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback
6453: ** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
6454: ** configured by this function.
6455: **
6456: ** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
6457: ** from SQL.
6458: **
6459: ** ^Every new [database connection] defaults to having the auto-checkpoint
6460: ** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
6461: ** pages. The use of this interface
6462: ** is only necessary if the default setting is found to be suboptimal
6463: ** for a particular application.
6464: */
6465: SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
6466:
6467: /*
6468: ** CAPI3REF: Checkpoint a database
6469: **
6470: ** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X
6471: ** on [database connection] D to be [checkpointed]. ^If X is NULL or an
6472: ** empty string, then a checkpoint is run on all databases of
6473: ** connection D. ^If the database connection D is not in
6474: ** [WAL | write-ahead log mode] then this interface is a harmless no-op.
6475: **
6476: ** ^The [wal_checkpoint pragma] can be used to invoke this interface
6477: ** from SQL. ^The [sqlite3_wal_autocheckpoint()] interface and the
6478: ** [wal_autocheckpoint pragma] can be used to cause this interface to be
6479: ** run whenever the WAL reaches a certain size threshold.
6480: **
6481: ** See also: [sqlite3_wal_checkpoint_v2()]
6482: */
6483: SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
6484:
6485: /*
6486: ** CAPI3REF: Checkpoint a database
6487: **
6488: ** Run a checkpoint operation on WAL database zDb attached to database
6489: ** handle db. The specific operation is determined by the value of the
6490: ** eMode parameter:
6491: **
6492: ** <dl>
6493: ** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
6494: ** Checkpoint as many frames as possible without waiting for any database
6495: ** readers or writers to finish. Sync the db file if all frames in the log
6496: ** are checkpointed. This mode is the same as calling
6497: ** sqlite3_wal_checkpoint(). The busy-handler callback is never invoked.
6498: **
6499: ** <dt>SQLITE_CHECKPOINT_FULL<dd>
6500: ** This mode blocks (calls the busy-handler callback) until there is no
6501: ** database writer and all readers are reading from the most recent database
6502: ** snapshot. It then checkpoints all frames in the log file and syncs the
6503: ** database file. This call blocks database writers while it is running,
6504: ** but not database readers.
6505: **
6506: ** <dt>SQLITE_CHECKPOINT_RESTART<dd>
6507: ** This mode works the same way as SQLITE_CHECKPOINT_FULL, except after
6508: ** checkpointing the log file it blocks (calls the busy-handler callback)
6509: ** until all readers are reading from the database file only. This ensures
6510: ** that the next client to write to the database file restarts the log file
6511: ** from the beginning. This call blocks database writers while it is running,
6512: ** but not database readers.
6513: ** </dl>
6514: **
6515: ** If pnLog is not NULL, then *pnLog is set to the total number of frames in
6516: ** the log file before returning. If pnCkpt is not NULL, then *pnCkpt is set to
6517: ** the total number of checkpointed frames (including any that were already
6518: ** checkpointed when this function is called). *pnLog and *pnCkpt may be
6519: ** populated even if sqlite3_wal_checkpoint_v2() returns other than SQLITE_OK.
6520: ** If no values are available because of an error, they are both set to -1
6521: ** before returning to communicate this to the caller.
6522: **
6523: ** All calls obtain an exclusive "checkpoint" lock on the database file. If
6524: ** any other process is running a checkpoint operation at the same time, the
6525: ** lock cannot be obtained and SQLITE_BUSY is returned. Even if there is a
6526: ** busy-handler configured, it will not be invoked in this case.
6527: **
6528: ** The SQLITE_CHECKPOINT_FULL and RESTART modes also obtain the exclusive
6529: ** "writer" lock on the database file. If the writer lock cannot be obtained
6530: ** immediately, and a busy-handler is configured, it is invoked and the writer
6531: ** lock retried until either the busy-handler returns 0 or the lock is
6532: ** successfully obtained. The busy-handler is also invoked while waiting for
6533: ** database readers as described above. If the busy-handler returns 0 before
6534: ** the writer lock is obtained or while waiting for database readers, the
6535: ** checkpoint operation proceeds from that point in the same way as
6536: ** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible
6537: ** without blocking any further. SQLITE_BUSY is returned in this case.
6538: **
6539: ** If parameter zDb is NULL or points to a zero length string, then the
6540: ** specified operation is attempted on all WAL databases. In this case the
6541: ** values written to output parameters *pnLog and *pnCkpt are undefined. If
6542: ** an SQLITE_BUSY error is encountered when processing one or more of the
6543: ** attached WAL databases, the operation is still attempted on any remaining
6544: ** attached databases and SQLITE_BUSY is returned to the caller. If any other
6545: ** error occurs while processing an attached database, processing is abandoned
6546: ** and the error code returned to the caller immediately. If no error
6547: ** (SQLITE_BUSY or otherwise) is encountered while processing the attached
6548: ** databases, SQLITE_OK is returned.
6549: **
6550: ** If database zDb is the name of an attached database that is not in WAL
6551: ** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. If
6552: ** zDb is not NULL (or a zero length string) and is not the name of any
6553: ** attached database, SQLITE_ERROR is returned to the caller.
6554: */
6555: SQLITE_API int sqlite3_wal_checkpoint_v2(
6556: sqlite3 *db, /* Database handle */
6557: const char *zDb, /* Name of attached database (or NULL) */
6558: int eMode, /* SQLITE_CHECKPOINT_* value */
6559: int *pnLog, /* OUT: Size of WAL log in frames */
6560: int *pnCkpt /* OUT: Total number of frames checkpointed */
6561: );
6562:
6563: /*
6564: ** CAPI3REF: Checkpoint operation parameters
6565: **
6566: ** These constants can be used as the 3rd parameter to
6567: ** [sqlite3_wal_checkpoint_v2()]. See the [sqlite3_wal_checkpoint_v2()]
6568: ** documentation for additional information about the meaning and use of
6569: ** each of these values.
6570: */
6571: #define SQLITE_CHECKPOINT_PASSIVE 0
6572: #define SQLITE_CHECKPOINT_FULL 1
6573: #define SQLITE_CHECKPOINT_RESTART 2
6574:
6575: /*
6576: ** CAPI3REF: Virtual Table Interface Configuration
6577: **
6578: ** This function may be called by either the [xConnect] or [xCreate] method
6579: ** of a [virtual table] implementation to configure
6580: ** various facets of the virtual table interface.
6581: **
6582: ** If this interface is invoked outside the context of an xConnect or
6583: ** xCreate virtual table method then the behavior is undefined.
6584: **
6585: ** At present, there is only one option that may be configured using
6586: ** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options
6587: ** may be added in the future.
6588: */
6589: SQLITE_API int sqlite3_vtab_config(sqlite3*, int op, ...);
6590:
6591: /*
6592: ** CAPI3REF: Virtual Table Configuration Options
6593: **
6594: ** These macros define the various options to the
6595: ** [sqlite3_vtab_config()] interface that [virtual table] implementations
6596: ** can use to customize and optimize their behavior.
6597: **
6598: ** <dl>
6599: ** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT
6600: ** <dd>Calls of the form
6601: ** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
6602: ** where X is an integer. If X is zero, then the [virtual table] whose
6603: ** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not
6604: ** support constraints. In this configuration (which is the default) if
6605: ** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire
6606: ** statement is rolled back as if [ON CONFLICT | OR ABORT] had been
6607: ** specified as part of the users SQL statement, regardless of the actual
6608: ** ON CONFLICT mode specified.
6609: **
6610: ** If X is non-zero, then the virtual table implementation guarantees
6611: ** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before
6612: ** any modifications to internal or persistent data structures have been made.
6613: ** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite
6614: ** is able to roll back a statement or database transaction, and abandon
6615: ** or continue processing the current SQL statement as appropriate.
6616: ** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns
6617: ** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode
6618: ** had been ABORT.
6619: **
6620: ** Virtual table implementations that are required to handle OR REPLACE
6621: ** must do so within the [xUpdate] method. If a call to the
6622: ** [sqlite3_vtab_on_conflict()] function indicates that the current ON
6623: ** CONFLICT policy is REPLACE, the virtual table implementation should
6624: ** silently replace the appropriate rows within the xUpdate callback and
6625: ** return SQLITE_OK. Or, if this is not possible, it may return
6626: ** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT
6627: ** constraint handling.
6628: ** </dl>
6629: */
6630: #define SQLITE_VTAB_CONSTRAINT_SUPPORT 1
6631:
6632: /*
6633: ** CAPI3REF: Determine The Virtual Table Conflict Policy
6634: **
6635: ** This function may only be called from within a call to the [xUpdate] method
6636: ** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The
6637: ** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
6638: ** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
6639: ** of the SQL statement that triggered the call to the [xUpdate] method of the
6640: ** [virtual table].
6641: */
6642: SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *);
6643:
6644: /*
6645: ** CAPI3REF: Conflict resolution modes
6646: **
6647: ** These constants are returned by [sqlite3_vtab_on_conflict()] to
6648: ** inform a [virtual table] implementation what the [ON CONFLICT] mode
6649: ** is for the SQL statement being evaluated.
6650: **
6651: ** Note that the [SQLITE_IGNORE] constant is also used as a potential
6652: ** return value from the [sqlite3_set_authorizer()] callback and that
6653: ** [SQLITE_ABORT] is also a [result code].
6654: */
6655: #define SQLITE_ROLLBACK 1
6656: /* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
6657: #define SQLITE_FAIL 3
6658: /* #define SQLITE_ABORT 4 // Also an error code */
6659: #define SQLITE_REPLACE 5
6660:
6661:
6662:
6663: /*
6664: ** Undo the hack that converts floating point types to integer for
6665: ** builds on processors without floating point support.
6666: */
6667: #ifdef SQLITE_OMIT_FLOATING_POINT
6668: # undef double
6669: #endif
6670:
6671: #ifdef __cplusplus
6672: } /* End of the 'extern "C"' block */
6673: #endif
6674: #endif
6675:
6676: /*
6677: ** 2010 August 30
6678: **
6679: ** The author disclaims copyright to this source code. In place of
6680: ** a legal notice, here is a blessing:
6681: **
6682: ** May you do good and not evil.
6683: ** May you find forgiveness for yourself and forgive others.
6684: ** May you share freely, never taking more than you give.
6685: **
6686: *************************************************************************
6687: */
6688:
6689: #ifndef _SQLITE3RTREE_H_
6690: #define _SQLITE3RTREE_H_
6691:
6692:
6693: #ifdef __cplusplus
6694: extern "C" {
6695: #endif
6696:
6697: typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry;
6698:
6699: /*
6700: ** Register a geometry callback named zGeom that can be used as part of an
6701: ** R-Tree geometry query as follows:
6702: **
6703: ** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...)
6704: */
6705: SQLITE_API int sqlite3_rtree_geometry_callback(
6706: sqlite3 *db,
6707: const char *zGeom,
6708: int (*xGeom)(sqlite3_rtree_geometry *, int nCoord, double *aCoord, int *pRes),
6709: void *pContext
6710: );
6711:
6712:
6713: /*
6714: ** A pointer to a structure of the following type is passed as the first
6715: ** argument to callbacks registered using rtree_geometry_callback().
6716: */
6717: struct sqlite3_rtree_geometry {
6718: void *pContext; /* Copy of pContext passed to s_r_g_c() */
6719: int nParam; /* Size of array aParam[] */
6720: double *aParam; /* Parameters passed to SQL geom function */
6721: void *pUser; /* Callback implementation user data */
6722: void (*xDelUser)(void *); /* Called by SQLite to clean up pUser */
6723: };
6724:
6725:
6726: #ifdef __cplusplus
6727: } /* end of the 'extern "C"' block */
6728: #endif
6729:
6730: #endif /* ifndef _SQLITE3RTREE_H_ */
6731:
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