Annotation of elwix/files/sqlite/dist/sqlite3.h, revision 1.3
1.2 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: */
1.3 ! misho 110: #define SQLITE_VERSION "3.7.15.2"
! 111: #define SQLITE_VERSION_NUMBER 3007015
! 112: #define SQLITE_SOURCE_ID "2013-01-09 11:53:05 c0e09560d26f0a6456be9dd3447f5311eb4f238f"
1.2 misho 113:
114: /*
115: ** CAPI3REF: Run-Time Library Version Numbers
116: ** KEYWORDS: sqlite3_version, sqlite3_sourceid
117: **
118: ** These interfaces provide the same information as the [SQLITE_VERSION],
119: ** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros
120: ** but are associated with the library instead of the header file. ^(Cautious
121: ** programmers might include assert() statements in their application to
122: ** verify that values returned by these interfaces match the macros in
123: ** the header, and thus insure that the application is
124: ** compiled with matching library and header files.
125: **
126: ** <blockquote><pre>
127: ** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
128: ** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 );
129: ** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
130: ** </pre></blockquote>)^
131: **
132: ** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION]
133: ** macro. ^The sqlite3_libversion() function returns a pointer to the
134: ** to the sqlite3_version[] string constant. The sqlite3_libversion()
135: ** function is provided for use in DLLs since DLL users usually do not have
136: ** direct access to string constants within the DLL. ^The
137: ** sqlite3_libversion_number() function returns an integer equal to
138: ** [SQLITE_VERSION_NUMBER]. ^The sqlite3_sourceid() function returns
139: ** a pointer to a string constant whose value is the same as the
140: ** [SQLITE_SOURCE_ID] C preprocessor macro.
141: **
142: ** See also: [sqlite_version()] and [sqlite_source_id()].
143: */
144: SQLITE_API SQLITE_EXTERN const char sqlite3_version[];
145: SQLITE_API const char *sqlite3_libversion(void);
146: SQLITE_API const char *sqlite3_sourceid(void);
147: SQLITE_API int sqlite3_libversion_number(void);
148:
149: /*
150: ** CAPI3REF: Run-Time Library Compilation Options Diagnostics
151: **
152: ** ^The sqlite3_compileoption_used() function returns 0 or 1
153: ** indicating whether the specified option was defined at
154: ** compile time. ^The SQLITE_ prefix may be omitted from the
155: ** option name passed to sqlite3_compileoption_used().
156: **
157: ** ^The sqlite3_compileoption_get() function allows iterating
158: ** over the list of options that were defined at compile time by
159: ** returning the N-th compile time option string. ^If N is out of range,
160: ** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_
161: ** prefix is omitted from any strings returned by
162: ** sqlite3_compileoption_get().
163: **
164: ** ^Support for the diagnostic functions sqlite3_compileoption_used()
165: ** and sqlite3_compileoption_get() may be omitted by specifying the
166: ** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time.
167: **
168: ** See also: SQL functions [sqlite_compileoption_used()] and
169: ** [sqlite_compileoption_get()] and the [compile_options pragma].
170: */
171: #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
172: SQLITE_API int sqlite3_compileoption_used(const char *zOptName);
173: SQLITE_API const char *sqlite3_compileoption_get(int N);
174: #endif
175:
176: /*
177: ** CAPI3REF: Test To See If The Library Is Threadsafe
178: **
179: ** ^The sqlite3_threadsafe() function returns zero if and only if
180: ** SQLite was compiled with mutexing code omitted due to the
181: ** [SQLITE_THREADSAFE] compile-time option being set to 0.
182: **
183: ** SQLite can be compiled with or without mutexes. When
184: ** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
185: ** are enabled and SQLite is threadsafe. When the
186: ** [SQLITE_THREADSAFE] macro is 0,
187: ** the mutexes are omitted. Without the mutexes, it is not safe
188: ** to use SQLite concurrently from more than one thread.
189: **
190: ** Enabling mutexes incurs a measurable performance penalty.
191: ** So if speed is of utmost importance, it makes sense to disable
192: ** the mutexes. But for maximum safety, mutexes should be enabled.
193: ** ^The default behavior is for mutexes to be enabled.
194: **
195: ** This interface can be used by an application to make sure that the
196: ** version of SQLite that it is linking against was compiled with
197: ** the desired setting of the [SQLITE_THREADSAFE] macro.
198: **
199: ** This interface only reports on the compile-time mutex setting
200: ** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with
201: ** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
202: ** can be fully or partially disabled using a call to [sqlite3_config()]
203: ** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD],
204: ** or [SQLITE_CONFIG_MUTEX]. ^(The return value of the
205: ** sqlite3_threadsafe() function shows only the compile-time setting of
206: ** thread safety, not any run-time changes to that setting made by
207: ** sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
208: ** is unchanged by calls to sqlite3_config().)^
209: **
210: ** See the [threading mode] documentation for additional information.
211: */
212: SQLITE_API int sqlite3_threadsafe(void);
213:
214: /*
215: ** CAPI3REF: Database Connection Handle
216: ** KEYWORDS: {database connection} {database connections}
217: **
218: ** Each open SQLite database is represented by a pointer to an instance of
219: ** the opaque structure named "sqlite3". It is useful to think of an sqlite3
220: ** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and
221: ** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
1.3 ! misho 222: ** and [sqlite3_close_v2()] are its destructors. There are many other
! 223: ** interfaces (such as
1.2 misho 224: ** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
225: ** [sqlite3_busy_timeout()] to name but three) that are methods on an
226: ** sqlite3 object.
227: */
228: typedef struct sqlite3 sqlite3;
229:
230: /*
231: ** CAPI3REF: 64-Bit Integer Types
232: ** KEYWORDS: sqlite_int64 sqlite_uint64
233: **
234: ** Because there is no cross-platform way to specify 64-bit integer types
235: ** SQLite includes typedefs for 64-bit signed and unsigned integers.
236: **
237: ** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
238: ** The sqlite_int64 and sqlite_uint64 types are supported for backwards
239: ** compatibility only.
240: **
241: ** ^The sqlite3_int64 and sqlite_int64 types can store integer values
242: ** between -9223372036854775808 and +9223372036854775807 inclusive. ^The
243: ** sqlite3_uint64 and sqlite_uint64 types can store integer values
244: ** between 0 and +18446744073709551615 inclusive.
245: */
246: #ifdef SQLITE_INT64_TYPE
247: typedef SQLITE_INT64_TYPE sqlite_int64;
248: typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
249: #elif defined(_MSC_VER) || defined(__BORLANDC__)
250: typedef __int64 sqlite_int64;
251: typedef unsigned __int64 sqlite_uint64;
252: #else
253: typedef long long int sqlite_int64;
254: typedef unsigned long long int sqlite_uint64;
255: #endif
256: typedef sqlite_int64 sqlite3_int64;
257: typedef sqlite_uint64 sqlite3_uint64;
258:
259: /*
260: ** If compiling for a processor that lacks floating point support,
261: ** substitute integer for floating-point.
262: */
263: #ifdef SQLITE_OMIT_FLOATING_POINT
264: # define double sqlite3_int64
265: #endif
266:
267: /*
268: ** CAPI3REF: Closing A Database Connection
269: **
1.3 ! misho 270: ** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors
! 271: ** for the [sqlite3] object.
! 272: ** ^Calls to sqlite3_close() and sqlite3_close_v2() return SQLITE_OK if
! 273: ** the [sqlite3] object is successfully destroyed and all associated
! 274: ** resources are deallocated.
! 275: **
! 276: ** ^If the database connection is associated with unfinalized prepared
! 277: ** statements or unfinished sqlite3_backup objects then sqlite3_close()
! 278: ** will leave the database connection open and return [SQLITE_BUSY].
! 279: ** ^If sqlite3_close_v2() is called with unfinalized prepared statements
! 280: ** and unfinished sqlite3_backups, then the database connection becomes
! 281: ** an unusable "zombie" which will automatically be deallocated when the
! 282: ** last prepared statement is finalized or the last sqlite3_backup is
! 283: ** finished. The sqlite3_close_v2() interface is intended for use with
! 284: ** host languages that are garbage collected, and where the order in which
! 285: ** destructors are called is arbitrary.
! 286: **
! 287: ** Applications should [sqlite3_finalize | finalize] all [prepared statements],
! 288: ** [sqlite3_blob_close | close] all [BLOB handles], and
! 289: ** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated
! 290: ** with the [sqlite3] object prior to attempting to close the object. ^If
1.2 misho 291: ** sqlite3_close() is called on a [database connection] that still has
1.3 ! misho 292: ** outstanding [prepared statements], [BLOB handles], and/or
! 293: ** [sqlite3_backup] objects then it returns SQLITE_OK but the deallocation
! 294: ** of resources is deferred until all [prepared statements], [BLOB handles],
! 295: ** and [sqlite3_backup] objects are also destroyed.
1.2 misho 296: **
1.3 ! misho 297: ** ^If an [sqlite3] object is destroyed while a transaction is open,
1.2 misho 298: ** the transaction is automatically rolled back.
299: **
1.3 ! misho 300: ** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)]
! 301: ** must be either a NULL
1.2 misho 302: ** pointer or an [sqlite3] object pointer obtained
303: ** from [sqlite3_open()], [sqlite3_open16()], or
304: ** [sqlite3_open_v2()], and not previously closed.
1.3 ! misho 305: ** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer
! 306: ** argument is a harmless no-op.
1.2 misho 307: */
1.3 ! misho 308: SQLITE_API int sqlite3_close(sqlite3*);
! 309: SQLITE_API int sqlite3_close_v2(sqlite3*);
1.2 misho 310:
311: /*
312: ** The type for a callback function.
313: ** This is legacy and deprecated. It is included for historical
314: ** compatibility and is not documented.
315: */
316: typedef int (*sqlite3_callback)(void*,int,char**, char**);
317:
318: /*
319: ** CAPI3REF: One-Step Query Execution Interface
320: **
321: ** The sqlite3_exec() interface is a convenience wrapper around
322: ** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
323: ** that allows an application to run multiple statements of SQL
324: ** without having to use a lot of C code.
325: **
326: ** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
327: ** semicolon-separate SQL statements passed into its 2nd argument,
328: ** in the context of the [database connection] passed in as its 1st
329: ** argument. ^If the callback function of the 3rd argument to
330: ** sqlite3_exec() is not NULL, then it is invoked for each result row
331: ** coming out of the evaluated SQL statements. ^The 4th argument to
332: ** sqlite3_exec() is relayed through to the 1st argument of each
333: ** callback invocation. ^If the callback pointer to sqlite3_exec()
334: ** is NULL, then no callback is ever invoked and result rows are
335: ** ignored.
336: **
337: ** ^If an error occurs while evaluating the SQL statements passed into
338: ** sqlite3_exec(), then execution of the current statement stops and
339: ** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec()
340: ** is not NULL then any error message is written into memory obtained
341: ** from [sqlite3_malloc()] and passed back through the 5th parameter.
342: ** To avoid memory leaks, the application should invoke [sqlite3_free()]
343: ** on error message strings returned through the 5th parameter of
344: ** of sqlite3_exec() after the error message string is no longer needed.
345: ** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
346: ** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
347: ** NULL before returning.
348: **
349: ** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
350: ** routine returns SQLITE_ABORT without invoking the callback again and
351: ** without running any subsequent SQL statements.
352: **
353: ** ^The 2nd argument to the sqlite3_exec() callback function is the
354: ** number of columns in the result. ^The 3rd argument to the sqlite3_exec()
355: ** callback is an array of pointers to strings obtained as if from
356: ** [sqlite3_column_text()], one for each column. ^If an element of a
357: ** result row is NULL then the corresponding string pointer for the
358: ** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the
359: ** sqlite3_exec() callback is an array of pointers to strings where each
360: ** entry represents the name of corresponding result column as obtained
361: ** from [sqlite3_column_name()].
362: **
363: ** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
364: ** to an empty string, or a pointer that contains only whitespace and/or
365: ** SQL comments, then no SQL statements are evaluated and the database
366: ** is not changed.
367: **
368: ** Restrictions:
369: **
370: ** <ul>
371: ** <li> The application must insure that the 1st parameter to sqlite3_exec()
372: ** is a valid and open [database connection].
373: ** <li> The application must not close [database connection] specified by
374: ** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
375: ** <li> The application must not modify the SQL statement text passed into
376: ** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
377: ** </ul>
378: */
379: SQLITE_API int sqlite3_exec(
380: sqlite3*, /* An open database */
381: const char *sql, /* SQL to be evaluated */
382: int (*callback)(void*,int,char**,char**), /* Callback function */
383: void *, /* 1st argument to callback */
384: char **errmsg /* Error msg written here */
385: );
386:
387: /*
388: ** CAPI3REF: Result Codes
389: ** KEYWORDS: SQLITE_OK {error code} {error codes}
390: ** KEYWORDS: {result code} {result codes}
391: **
392: ** Many SQLite functions return an integer result code from the set shown
393: ** here in order to indicate success or failure.
394: **
395: ** New error codes may be added in future versions of SQLite.
396: **
397: ** See also: [SQLITE_IOERR_READ | extended result codes],
398: ** [sqlite3_vtab_on_conflict()] [SQLITE_ROLLBACK | result codes].
399: */
400: #define SQLITE_OK 0 /* Successful result */
401: /* beginning-of-error-codes */
402: #define SQLITE_ERROR 1 /* SQL error or missing database */
403: #define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */
404: #define SQLITE_PERM 3 /* Access permission denied */
405: #define SQLITE_ABORT 4 /* Callback routine requested an abort */
406: #define SQLITE_BUSY 5 /* The database file is locked */
407: #define SQLITE_LOCKED 6 /* A table in the database is locked */
408: #define SQLITE_NOMEM 7 /* A malloc() failed */
409: #define SQLITE_READONLY 8 /* Attempt to write a readonly database */
410: #define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/
411: #define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */
412: #define SQLITE_CORRUPT 11 /* The database disk image is malformed */
413: #define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */
414: #define SQLITE_FULL 13 /* Insertion failed because database is full */
415: #define SQLITE_CANTOPEN 14 /* Unable to open the database file */
416: #define SQLITE_PROTOCOL 15 /* Database lock protocol error */
417: #define SQLITE_EMPTY 16 /* Database is empty */
418: #define SQLITE_SCHEMA 17 /* The database schema changed */
419: #define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */
420: #define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */
421: #define SQLITE_MISMATCH 20 /* Data type mismatch */
422: #define SQLITE_MISUSE 21 /* Library used incorrectly */
423: #define SQLITE_NOLFS 22 /* Uses OS features not supported on host */
424: #define SQLITE_AUTH 23 /* Authorization denied */
425: #define SQLITE_FORMAT 24 /* Auxiliary database format error */
426: #define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */
427: #define SQLITE_NOTADB 26 /* File opened that is not a database file */
428: #define SQLITE_ROW 100 /* sqlite3_step() has another row ready */
429: #define SQLITE_DONE 101 /* sqlite3_step() has finished executing */
430: /* end-of-error-codes */
431:
432: /*
433: ** CAPI3REF: Extended Result Codes
434: ** KEYWORDS: {extended error code} {extended error codes}
435: ** KEYWORDS: {extended result code} {extended result codes}
436: **
437: ** In its default configuration, SQLite API routines return one of 26 integer
438: ** [SQLITE_OK | result codes]. However, experience has shown that many of
439: ** these result codes are too coarse-grained. They do not provide as
440: ** much information about problems as programmers might like. In an effort to
441: ** address this, newer versions of SQLite (version 3.3.8 and later) include
442: ** support for additional result codes that provide more detailed information
443: ** about errors. The extended result codes are enabled or disabled
444: ** on a per database connection basis using the
445: ** [sqlite3_extended_result_codes()] API.
446: **
447: ** Some of the available extended result codes are listed here.
448: ** One may expect the number of extended result codes will be expand
449: ** over time. Software that uses extended result codes should expect
450: ** to see new result codes in future releases of SQLite.
451: **
452: ** The SQLITE_OK result code will never be extended. It will always
453: ** be exactly zero.
454: */
455: #define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8))
456: #define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8))
457: #define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8))
458: #define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8))
459: #define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8))
460: #define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8))
461: #define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8))
462: #define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8))
463: #define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8))
464: #define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8))
465: #define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8))
466: #define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8))
467: #define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8))
468: #define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
469: #define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8))
470: #define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8))
471: #define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8))
472: #define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8))
473: #define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8))
474: #define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8))
475: #define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8))
476: #define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8))
1.3 ! misho 477: #define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8))
1.2 misho 478: #define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8))
479: #define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8))
480: #define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8))
1.3 ! misho 481: #define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8))
! 482: #define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8))
1.2 misho 483: #define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8))
484: #define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8))
485: #define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8))
1.3 ! misho 486: #define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8))
1.2 misho 487:
488: /*
489: ** CAPI3REF: Flags For File Open Operations
490: **
491: ** These bit values are intended for use in the
492: ** 3rd parameter to the [sqlite3_open_v2()] interface and
493: ** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
494: */
495: #define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */
496: #define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */
497: #define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */
498: #define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */
499: #define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */
500: #define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */
501: #define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */
1.3 ! misho 502: #define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */
1.2 misho 503: #define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */
504: #define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */
505: #define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */
506: #define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */
507: #define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */
508: #define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */
509: #define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */
510: #define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */
511: #define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */
512: #define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */
513: #define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */
514: #define SQLITE_OPEN_WAL 0x00080000 /* VFS only */
515:
516: /* Reserved: 0x00F00000 */
517:
518: /*
519: ** CAPI3REF: Device Characteristics
520: **
521: ** The xDeviceCharacteristics method of the [sqlite3_io_methods]
1.3 ! misho 522: ** object returns an integer which is a vector of these
1.2 misho 523: ** bit values expressing I/O characteristics of the mass storage
524: ** device that holds the file that the [sqlite3_io_methods]
525: ** refers to.
526: **
527: ** The SQLITE_IOCAP_ATOMIC property means that all writes of
528: ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
529: ** mean that writes of blocks that are nnn bytes in size and
530: ** are aligned to an address which is an integer multiple of
531: ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
532: ** that when data is appended to a file, the data is appended
533: ** first then the size of the file is extended, never the other
534: ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
535: ** information is written to disk in the same order as calls
536: ** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
537: ** after reboot following a crash or power loss, the only bytes in a
538: ** file that were written at the application level might have changed
539: ** and that adjacent bytes, even bytes within the same sector are
540: ** guaranteed to be unchanged.
541: */
542: #define SQLITE_IOCAP_ATOMIC 0x00000001
543: #define SQLITE_IOCAP_ATOMIC512 0x00000002
544: #define SQLITE_IOCAP_ATOMIC1K 0x00000004
545: #define SQLITE_IOCAP_ATOMIC2K 0x00000008
546: #define SQLITE_IOCAP_ATOMIC4K 0x00000010
547: #define SQLITE_IOCAP_ATOMIC8K 0x00000020
548: #define SQLITE_IOCAP_ATOMIC16K 0x00000040
549: #define SQLITE_IOCAP_ATOMIC32K 0x00000080
550: #define SQLITE_IOCAP_ATOMIC64K 0x00000100
551: #define SQLITE_IOCAP_SAFE_APPEND 0x00000200
552: #define SQLITE_IOCAP_SEQUENTIAL 0x00000400
553: #define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800
554: #define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000
555:
556: /*
557: ** CAPI3REF: File Locking Levels
558: **
559: ** SQLite uses one of these integer values as the second
560: ** argument to calls it makes to the xLock() and xUnlock() methods
561: ** of an [sqlite3_io_methods] object.
562: */
563: #define SQLITE_LOCK_NONE 0
564: #define SQLITE_LOCK_SHARED 1
565: #define SQLITE_LOCK_RESERVED 2
566: #define SQLITE_LOCK_PENDING 3
567: #define SQLITE_LOCK_EXCLUSIVE 4
568:
569: /*
570: ** CAPI3REF: Synchronization Type Flags
571: **
572: ** When SQLite invokes the xSync() method of an
573: ** [sqlite3_io_methods] object it uses a combination of
574: ** these integer values as the second argument.
575: **
576: ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
577: ** sync operation only needs to flush data to mass storage. Inode
578: ** information need not be flushed. If the lower four bits of the flag
579: ** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
580: ** If the lower four bits equal SQLITE_SYNC_FULL, that means
581: ** to use Mac OS X style fullsync instead of fsync().
582: **
583: ** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
584: ** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
585: ** settings. The [synchronous pragma] determines when calls to the
586: ** xSync VFS method occur and applies uniformly across all platforms.
587: ** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
588: ** energetic or rigorous or forceful the sync operations are and
589: ** only make a difference on Mac OSX for the default SQLite code.
590: ** (Third-party VFS implementations might also make the distinction
591: ** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
592: ** operating systems natively supported by SQLite, only Mac OSX
593: ** cares about the difference.)
594: */
595: #define SQLITE_SYNC_NORMAL 0x00002
596: #define SQLITE_SYNC_FULL 0x00003
597: #define SQLITE_SYNC_DATAONLY 0x00010
598:
599: /*
600: ** CAPI3REF: OS Interface Open File Handle
601: **
602: ** An [sqlite3_file] object represents an open file in the
603: ** [sqlite3_vfs | OS interface layer]. Individual OS interface
604: ** implementations will
605: ** want to subclass this object by appending additional fields
606: ** for their own use. The pMethods entry is a pointer to an
607: ** [sqlite3_io_methods] object that defines methods for performing
608: ** I/O operations on the open file.
609: */
610: typedef struct sqlite3_file sqlite3_file;
611: struct sqlite3_file {
612: const struct sqlite3_io_methods *pMethods; /* Methods for an open file */
613: };
614:
615: /*
616: ** CAPI3REF: OS Interface File Virtual Methods Object
617: **
618: ** Every file opened by the [sqlite3_vfs.xOpen] method populates an
619: ** [sqlite3_file] object (or, more commonly, a subclass of the
620: ** [sqlite3_file] object) with a pointer to an instance of this object.
621: ** This object defines the methods used to perform various operations
622: ** against the open file represented by the [sqlite3_file] object.
623: **
624: ** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element
625: ** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
626: ** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The
627: ** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
628: ** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
629: ** to NULL.
630: **
631: ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
632: ** [SQLITE_SYNC_FULL]. The first choice is the normal fsync().
633: ** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY]
634: ** flag may be ORed in to indicate that only the data of the file
635: ** and not its inode needs to be synced.
636: **
637: ** The integer values to xLock() and xUnlock() are one of
638: ** <ul>
639: ** <li> [SQLITE_LOCK_NONE],
640: ** <li> [SQLITE_LOCK_SHARED],
641: ** <li> [SQLITE_LOCK_RESERVED],
642: ** <li> [SQLITE_LOCK_PENDING], or
643: ** <li> [SQLITE_LOCK_EXCLUSIVE].
644: ** </ul>
645: ** xLock() increases the lock. xUnlock() decreases the lock.
646: ** The xCheckReservedLock() method checks whether any database connection,
647: ** either in this process or in some other process, is holding a RESERVED,
648: ** PENDING, or EXCLUSIVE lock on the file. It returns true
649: ** if such a lock exists and false otherwise.
650: **
651: ** The xFileControl() method is a generic interface that allows custom
652: ** VFS implementations to directly control an open file using the
653: ** [sqlite3_file_control()] interface. The second "op" argument is an
654: ** integer opcode. The third argument is a generic pointer intended to
655: ** point to a structure that may contain arguments or space in which to
656: ** write return values. Potential uses for xFileControl() might be
657: ** functions to enable blocking locks with timeouts, to change the
658: ** locking strategy (for example to use dot-file locks), to inquire
659: ** about the status of a lock, or to break stale locks. The SQLite
660: ** core reserves all opcodes less than 100 for its own use.
661: ** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available.
662: ** Applications that define a custom xFileControl method should use opcodes
663: ** greater than 100 to avoid conflicts. VFS implementations should
664: ** return [SQLITE_NOTFOUND] for file control opcodes that they do not
665: ** recognize.
666: **
667: ** The xSectorSize() method returns the sector size of the
668: ** device that underlies the file. The sector size is the
669: ** minimum write that can be performed without disturbing
670: ** other bytes in the file. The xDeviceCharacteristics()
671: ** method returns a bit vector describing behaviors of the
672: ** underlying device:
673: **
674: ** <ul>
675: ** <li> [SQLITE_IOCAP_ATOMIC]
676: ** <li> [SQLITE_IOCAP_ATOMIC512]
677: ** <li> [SQLITE_IOCAP_ATOMIC1K]
678: ** <li> [SQLITE_IOCAP_ATOMIC2K]
679: ** <li> [SQLITE_IOCAP_ATOMIC4K]
680: ** <li> [SQLITE_IOCAP_ATOMIC8K]
681: ** <li> [SQLITE_IOCAP_ATOMIC16K]
682: ** <li> [SQLITE_IOCAP_ATOMIC32K]
683: ** <li> [SQLITE_IOCAP_ATOMIC64K]
684: ** <li> [SQLITE_IOCAP_SAFE_APPEND]
685: ** <li> [SQLITE_IOCAP_SEQUENTIAL]
686: ** </ul>
687: **
688: ** The SQLITE_IOCAP_ATOMIC property means that all writes of
689: ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
690: ** mean that writes of blocks that are nnn bytes in size and
691: ** are aligned to an address which is an integer multiple of
692: ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
693: ** that when data is appended to a file, the data is appended
694: ** first then the size of the file is extended, never the other
695: ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
696: ** information is written to disk in the same order as calls
697: ** to xWrite().
698: **
699: ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
700: ** in the unread portions of the buffer with zeros. A VFS that
701: ** fails to zero-fill short reads might seem to work. However,
702: ** failure to zero-fill short reads will eventually lead to
703: ** database corruption.
704: */
705: typedef struct sqlite3_io_methods sqlite3_io_methods;
706: struct sqlite3_io_methods {
707: int iVersion;
708: int (*xClose)(sqlite3_file*);
709: int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
710: int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
711: int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
712: int (*xSync)(sqlite3_file*, int flags);
713: int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
714: int (*xLock)(sqlite3_file*, int);
715: int (*xUnlock)(sqlite3_file*, int);
716: int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
717: int (*xFileControl)(sqlite3_file*, int op, void *pArg);
718: int (*xSectorSize)(sqlite3_file*);
719: int (*xDeviceCharacteristics)(sqlite3_file*);
720: /* Methods above are valid for version 1 */
721: int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
722: int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
723: void (*xShmBarrier)(sqlite3_file*);
724: int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
725: /* Methods above are valid for version 2 */
726: /* Additional methods may be added in future releases */
727: };
728:
729: /*
730: ** CAPI3REF: Standard File Control Opcodes
731: **
732: ** These integer constants are opcodes for the xFileControl method
733: ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
734: ** interface.
735: **
736: ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This
737: ** opcode causes the xFileControl method to write the current state of
738: ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
739: ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
740: ** into an integer that the pArg argument points to. This capability
741: ** is used during testing and only needs to be supported when SQLITE_TEST
742: ** is defined.
1.3 ! misho 743: ** <ul>
! 744: ** <li>[[SQLITE_FCNTL_SIZE_HINT]]
1.2 misho 745: ** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
746: ** layer a hint of how large the database file will grow to be during the
747: ** current transaction. This hint is not guaranteed to be accurate but it
748: ** is often close. The underlying VFS might choose to preallocate database
749: ** file space based on this hint in order to help writes to the database
750: ** file run faster.
751: **
1.3 ! misho 752: ** <li>[[SQLITE_FCNTL_CHUNK_SIZE]]
1.2 misho 753: ** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
754: ** extends and truncates the database file in chunks of a size specified
755: ** by the user. The fourth argument to [sqlite3_file_control()] should
756: ** point to an integer (type int) containing the new chunk-size to use
757: ** for the nominated database. Allocating database file space in large
758: ** chunks (say 1MB at a time), may reduce file-system fragmentation and
759: ** improve performance on some systems.
760: **
1.3 ! misho 761: ** <li>[[SQLITE_FCNTL_FILE_POINTER]]
1.2 misho 762: ** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
763: ** to the [sqlite3_file] object associated with a particular database
764: ** connection. See the [sqlite3_file_control()] documentation for
765: ** additional information.
766: **
1.3 ! misho 767: ** <li>[[SQLITE_FCNTL_SYNC_OMITTED]]
1.2 misho 768: ** ^(The [SQLITE_FCNTL_SYNC_OMITTED] opcode is generated internally by
769: ** SQLite and sent to all VFSes in place of a call to the xSync method
770: ** when the database connection has [PRAGMA synchronous] set to OFF.)^
771: ** Some specialized VFSes need this signal in order to operate correctly
772: ** when [PRAGMA synchronous | PRAGMA synchronous=OFF] is set, but most
773: ** VFSes do not need this signal and should silently ignore this opcode.
774: ** Applications should not call [sqlite3_file_control()] with this
775: ** opcode as doing so may disrupt the operation of the specialized VFSes
776: ** that do require it.
777: **
1.3 ! misho 778: ** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]]
1.2 misho 779: ** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
780: ** retry counts and intervals for certain disk I/O operations for the
781: ** windows [VFS] in order to provide robustness in the presence of
782: ** anti-virus programs. By default, the windows VFS will retry file read,
783: ** file write, and file delete operations up to 10 times, with a delay
784: ** of 25 milliseconds before the first retry and with the delay increasing
785: ** by an additional 25 milliseconds with each subsequent retry. This
786: ** opcode allows these two values (10 retries and 25 milliseconds of delay)
787: ** to be adjusted. The values are changed for all database connections
788: ** within the same process. The argument is a pointer to an array of two
789: ** integers where the first integer i the new retry count and the second
790: ** integer is the delay. If either integer is negative, then the setting
791: ** is not changed but instead the prior value of that setting is written
792: ** into the array entry, allowing the current retry settings to be
793: ** interrogated. The zDbName parameter is ignored.
794: **
1.3 ! misho 795: ** <li>[[SQLITE_FCNTL_PERSIST_WAL]]
1.2 misho 796: ** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
1.3 ! misho 797: ** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary
1.2 misho 798: ** write ahead log and shared memory files used for transaction control
799: ** are automatically deleted when the latest connection to the database
800: ** closes. Setting persistent WAL mode causes those files to persist after
801: ** close. Persisting the files is useful when other processes that do not
802: ** have write permission on the directory containing the database file want
803: ** to read the database file, as the WAL and shared memory files must exist
804: ** in order for the database to be readable. The fourth parameter to
805: ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
806: ** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
807: ** WAL mode. If the integer is -1, then it is overwritten with the current
808: ** WAL persistence setting.
809: **
1.3 ! misho 810: ** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]]
1.2 misho 811: ** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
812: ** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting
813: ** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
814: ** xDeviceCharacteristics methods. The fourth parameter to
815: ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
816: ** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
817: ** mode. If the integer is -1, then it is overwritten with the current
818: ** zero-damage mode setting.
819: **
1.3 ! misho 820: ** <li>[[SQLITE_FCNTL_OVERWRITE]]
1.2 misho 821: ** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
822: ** a write transaction to indicate that, unless it is rolled back for some
823: ** reason, the entire database file will be overwritten by the current
824: ** transaction. This is used by VACUUM operations.
825: **
1.3 ! misho 826: ** <li>[[SQLITE_FCNTL_VFSNAME]]
1.2 misho 827: ** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
828: ** all [VFSes] in the VFS stack. The names are of all VFS shims and the
829: ** final bottom-level VFS are written into memory obtained from
830: ** [sqlite3_malloc()] and the result is stored in the char* variable
831: ** that the fourth parameter of [sqlite3_file_control()] points to.
832: ** The caller is responsible for freeing the memory when done. As with
833: ** all file-control actions, there is no guarantee that this will actually
834: ** do anything. Callers should initialize the char* variable to a NULL
835: ** pointer in case this file-control is not implemented. This file-control
836: ** is intended for diagnostic use only.
1.3 ! misho 837: **
! 838: ** <li>[[SQLITE_FCNTL_PRAGMA]]
! 839: ** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA]
! 840: ** file control is sent to the open [sqlite3_file] object corresponding
! 841: ** to the database file to which the pragma statement refers. ^The argument
! 842: ** to the [SQLITE_FCNTL_PRAGMA] file control is an array of
! 843: ** pointers to strings (char**) in which the second element of the array
! 844: ** is the name of the pragma and the third element is the argument to the
! 845: ** pragma or NULL if the pragma has no argument. ^The handler for an
! 846: ** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element
! 847: ** of the char** argument point to a string obtained from [sqlite3_mprintf()]
! 848: ** or the equivalent and that string will become the result of the pragma or
! 849: ** the error message if the pragma fails. ^If the
! 850: ** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal
! 851: ** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA]
! 852: ** file control returns [SQLITE_OK], then the parser assumes that the
! 853: ** VFS has handled the PRAGMA itself and the parser generates a no-op
! 854: ** prepared statement. ^If the [SQLITE_FCNTL_PRAGMA] file control returns
! 855: ** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means
! 856: ** that the VFS encountered an error while handling the [PRAGMA] and the
! 857: ** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA]
! 858: ** file control occurs at the beginning of pragma statement analysis and so
! 859: ** it is able to override built-in [PRAGMA] statements.
! 860: **
! 861: ** <li>[[SQLITE_FCNTL_BUSYHANDLER]]
! 862: ** ^This file-control may be invoked by SQLite on the database file handle
! 863: ** shortly after it is opened in order to provide a custom VFS with access
! 864: ** to the connections busy-handler callback. The argument is of type (void **)
! 865: ** - an array of two (void *) values. The first (void *) actually points
! 866: ** to a function of type (int (*)(void *)). In order to invoke the connections
! 867: ** busy-handler, this function should be invoked with the second (void *) in
! 868: ** the array as the only argument. If it returns non-zero, then the operation
! 869: ** should be retried. If it returns zero, the custom VFS should abandon the
! 870: ** current operation.
! 871: **
! 872: ** <li>[[SQLITE_FCNTL_TEMPFILENAME]]
! 873: ** ^Application can invoke this file-control to have SQLite generate a
! 874: ** temporary filename using the same algorithm that is followed to generate
! 875: ** temporary filenames for TEMP tables and other internal uses. The
! 876: ** argument should be a char** which will be filled with the filename
! 877: ** written into memory obtained from [sqlite3_malloc()]. The caller should
! 878: ** invoke [sqlite3_free()] on the result to avoid a memory leak.
! 879: **
! 880: ** </ul>
1.2 misho 881: */
882: #define SQLITE_FCNTL_LOCKSTATE 1
883: #define SQLITE_GET_LOCKPROXYFILE 2
884: #define SQLITE_SET_LOCKPROXYFILE 3
885: #define SQLITE_LAST_ERRNO 4
886: #define SQLITE_FCNTL_SIZE_HINT 5
887: #define SQLITE_FCNTL_CHUNK_SIZE 6
888: #define SQLITE_FCNTL_FILE_POINTER 7
889: #define SQLITE_FCNTL_SYNC_OMITTED 8
890: #define SQLITE_FCNTL_WIN32_AV_RETRY 9
891: #define SQLITE_FCNTL_PERSIST_WAL 10
892: #define SQLITE_FCNTL_OVERWRITE 11
893: #define SQLITE_FCNTL_VFSNAME 12
894: #define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13
1.3 ! misho 895: #define SQLITE_FCNTL_PRAGMA 14
! 896: #define SQLITE_FCNTL_BUSYHANDLER 15
! 897: #define SQLITE_FCNTL_TEMPFILENAME 16
1.2 misho 898:
899: /*
900: ** CAPI3REF: Mutex Handle
901: **
902: ** The mutex module within SQLite defines [sqlite3_mutex] to be an
903: ** abstract type for a mutex object. The SQLite core never looks
904: ** at the internal representation of an [sqlite3_mutex]. It only
905: ** deals with pointers to the [sqlite3_mutex] object.
906: **
907: ** Mutexes are created using [sqlite3_mutex_alloc()].
908: */
909: typedef struct sqlite3_mutex sqlite3_mutex;
910:
911: /*
912: ** CAPI3REF: OS Interface Object
913: **
914: ** An instance of the sqlite3_vfs object defines the interface between
915: ** the SQLite core and the underlying operating system. The "vfs"
916: ** in the name of the object stands for "virtual file system". See
917: ** the [VFS | VFS documentation] for further information.
918: **
919: ** The value of the iVersion field is initially 1 but may be larger in
920: ** future versions of SQLite. Additional fields may be appended to this
921: ** object when the iVersion value is increased. Note that the structure
922: ** of the sqlite3_vfs object changes in the transaction between
923: ** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not
924: ** modified.
925: **
926: ** The szOsFile field is the size of the subclassed [sqlite3_file]
927: ** structure used by this VFS. mxPathname is the maximum length of
928: ** a pathname in this VFS.
929: **
930: ** Registered sqlite3_vfs objects are kept on a linked list formed by
931: ** the pNext pointer. The [sqlite3_vfs_register()]
932: ** and [sqlite3_vfs_unregister()] interfaces manage this list
933: ** in a thread-safe way. The [sqlite3_vfs_find()] interface
934: ** searches the list. Neither the application code nor the VFS
935: ** implementation should use the pNext pointer.
936: **
937: ** The pNext field is the only field in the sqlite3_vfs
938: ** structure that SQLite will ever modify. SQLite will only access
939: ** or modify this field while holding a particular static mutex.
940: ** The application should never modify anything within the sqlite3_vfs
941: ** object once the object has been registered.
942: **
943: ** The zName field holds the name of the VFS module. The name must
944: ** be unique across all VFS modules.
945: **
946: ** [[sqlite3_vfs.xOpen]]
947: ** ^SQLite guarantees that the zFilename parameter to xOpen
948: ** is either a NULL pointer or string obtained
949: ** from xFullPathname() with an optional suffix added.
950: ** ^If a suffix is added to the zFilename parameter, it will
951: ** consist of a single "-" character followed by no more than
952: ** 11 alphanumeric and/or "-" characters.
953: ** ^SQLite further guarantees that
954: ** the string will be valid and unchanged until xClose() is
955: ** called. Because of the previous sentence,
956: ** the [sqlite3_file] can safely store a pointer to the
957: ** filename if it needs to remember the filename for some reason.
958: ** If the zFilename parameter to xOpen is a NULL pointer then xOpen
959: ** must invent its own temporary name for the file. ^Whenever the
960: ** xFilename parameter is NULL it will also be the case that the
961: ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
962: **
963: ** The flags argument to xOpen() includes all bits set in
964: ** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()]
965: ** or [sqlite3_open16()] is used, then flags includes at least
966: ** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE].
967: ** If xOpen() opens a file read-only then it sets *pOutFlags to
968: ** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set.
969: **
970: ** ^(SQLite will also add one of the following flags to the xOpen()
971: ** call, depending on the object being opened:
972: **
973: ** <ul>
974: ** <li> [SQLITE_OPEN_MAIN_DB]
975: ** <li> [SQLITE_OPEN_MAIN_JOURNAL]
976: ** <li> [SQLITE_OPEN_TEMP_DB]
977: ** <li> [SQLITE_OPEN_TEMP_JOURNAL]
978: ** <li> [SQLITE_OPEN_TRANSIENT_DB]
979: ** <li> [SQLITE_OPEN_SUBJOURNAL]
980: ** <li> [SQLITE_OPEN_MASTER_JOURNAL]
981: ** <li> [SQLITE_OPEN_WAL]
982: ** </ul>)^
983: **
984: ** The file I/O implementation can use the object type flags to
985: ** change the way it deals with files. For example, an application
986: ** that does not care about crash recovery or rollback might make
987: ** the open of a journal file a no-op. Writes to this journal would
988: ** also be no-ops, and any attempt to read the journal would return
989: ** SQLITE_IOERR. Or the implementation might recognize that a database
990: ** file will be doing page-aligned sector reads and writes in a random
991: ** order and set up its I/O subsystem accordingly.
992: **
993: ** SQLite might also add one of the following flags to the xOpen method:
994: **
995: ** <ul>
996: ** <li> [SQLITE_OPEN_DELETEONCLOSE]
997: ** <li> [SQLITE_OPEN_EXCLUSIVE]
998: ** </ul>
999: **
1000: ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
1001: ** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE]
1002: ** will be set for TEMP databases and their journals, transient
1003: ** databases, and subjournals.
1004: **
1005: ** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
1006: ** with the [SQLITE_OPEN_CREATE] flag, which are both directly
1007: ** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
1008: ** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
1009: ** SQLITE_OPEN_CREATE, is used to indicate that file should always
1010: ** be created, and that it is an error if it already exists.
1011: ** It is <i>not</i> used to indicate the file should be opened
1012: ** for exclusive access.
1013: **
1014: ** ^At least szOsFile bytes of memory are allocated by SQLite
1015: ** to hold the [sqlite3_file] structure passed as the third
1016: ** argument to xOpen. The xOpen method does not have to
1017: ** allocate the structure; it should just fill it in. Note that
1018: ** the xOpen method must set the sqlite3_file.pMethods to either
1019: ** a valid [sqlite3_io_methods] object or to NULL. xOpen must do
1020: ** this even if the open fails. SQLite expects that the sqlite3_file.pMethods
1021: ** element will be valid after xOpen returns regardless of the success
1022: ** or failure of the xOpen call.
1023: **
1024: ** [[sqlite3_vfs.xAccess]]
1025: ** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
1026: ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
1027: ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
1028: ** to test whether a file is at least readable. The file can be a
1029: ** directory.
1030: **
1031: ** ^SQLite will always allocate at least mxPathname+1 bytes for the
1032: ** output buffer xFullPathname. The exact size of the output buffer
1033: ** is also passed as a parameter to both methods. If the output buffer
1034: ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
1035: ** handled as a fatal error by SQLite, vfs implementations should endeavor
1036: ** to prevent this by setting mxPathname to a sufficiently large value.
1037: **
1038: ** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
1039: ** interfaces are not strictly a part of the filesystem, but they are
1040: ** included in the VFS structure for completeness.
1041: ** The xRandomness() function attempts to return nBytes bytes
1042: ** of good-quality randomness into zOut. The return value is
1043: ** the actual number of bytes of randomness obtained.
1044: ** The xSleep() method causes the calling thread to sleep for at
1045: ** least the number of microseconds given. ^The xCurrentTime()
1046: ** method returns a Julian Day Number for the current date and time as
1047: ** a floating point value.
1048: ** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
1049: ** Day Number multiplied by 86400000 (the number of milliseconds in
1050: ** a 24-hour day).
1051: ** ^SQLite will use the xCurrentTimeInt64() method to get the current
1052: ** date and time if that method is available (if iVersion is 2 or
1053: ** greater and the function pointer is not NULL) and will fall back
1054: ** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
1055: **
1056: ** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
1057: ** are not used by the SQLite core. These optional interfaces are provided
1058: ** by some VFSes to facilitate testing of the VFS code. By overriding
1059: ** system calls with functions under its control, a test program can
1060: ** simulate faults and error conditions that would otherwise be difficult
1061: ** or impossible to induce. The set of system calls that can be overridden
1062: ** varies from one VFS to another, and from one version of the same VFS to the
1063: ** next. Applications that use these interfaces must be prepared for any
1064: ** or all of these interfaces to be NULL or for their behavior to change
1065: ** from one release to the next. Applications must not attempt to access
1066: ** any of these methods if the iVersion of the VFS is less than 3.
1067: */
1068: typedef struct sqlite3_vfs sqlite3_vfs;
1069: typedef void (*sqlite3_syscall_ptr)(void);
1070: struct sqlite3_vfs {
1071: int iVersion; /* Structure version number (currently 3) */
1072: int szOsFile; /* Size of subclassed sqlite3_file */
1073: int mxPathname; /* Maximum file pathname length */
1074: sqlite3_vfs *pNext; /* Next registered VFS */
1075: const char *zName; /* Name of this virtual file system */
1076: void *pAppData; /* Pointer to application-specific data */
1077: int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
1078: int flags, int *pOutFlags);
1079: int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
1080: int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
1081: int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
1082: void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
1083: void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
1084: void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
1085: void (*xDlClose)(sqlite3_vfs*, void*);
1086: int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
1087: int (*xSleep)(sqlite3_vfs*, int microseconds);
1088: int (*xCurrentTime)(sqlite3_vfs*, double*);
1089: int (*xGetLastError)(sqlite3_vfs*, int, char *);
1090: /*
1091: ** The methods above are in version 1 of the sqlite_vfs object
1092: ** definition. Those that follow are added in version 2 or later
1093: */
1094: int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
1095: /*
1096: ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
1097: ** Those below are for version 3 and greater.
1098: */
1099: int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
1100: sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
1101: const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
1102: /*
1103: ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
1104: ** New fields may be appended in figure versions. The iVersion
1105: ** value will increment whenever this happens.
1106: */
1107: };
1108:
1109: /*
1110: ** CAPI3REF: Flags for the xAccess VFS method
1111: **
1112: ** These integer constants can be used as the third parameter to
1113: ** the xAccess method of an [sqlite3_vfs] object. They determine
1114: ** what kind of permissions the xAccess method is looking for.
1115: ** With SQLITE_ACCESS_EXISTS, the xAccess method
1116: ** simply checks whether the file exists.
1117: ** With SQLITE_ACCESS_READWRITE, the xAccess method
1118: ** checks whether the named directory is both readable and writable
1119: ** (in other words, if files can be added, removed, and renamed within
1120: ** the directory).
1121: ** The SQLITE_ACCESS_READWRITE constant is currently used only by the
1122: ** [temp_store_directory pragma], though this could change in a future
1123: ** release of SQLite.
1124: ** With SQLITE_ACCESS_READ, the xAccess method
1125: ** checks whether the file is readable. The SQLITE_ACCESS_READ constant is
1126: ** currently unused, though it might be used in a future release of
1127: ** SQLite.
1128: */
1129: #define SQLITE_ACCESS_EXISTS 0
1130: #define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */
1131: #define SQLITE_ACCESS_READ 2 /* Unused */
1132:
1133: /*
1134: ** CAPI3REF: Flags for the xShmLock VFS method
1135: **
1136: ** These integer constants define the various locking operations
1137: ** allowed by the xShmLock method of [sqlite3_io_methods]. The
1138: ** following are the only legal combinations of flags to the
1139: ** xShmLock method:
1140: **
1141: ** <ul>
1142: ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
1143: ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
1144: ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
1145: ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
1146: ** </ul>
1147: **
1148: ** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
1149: ** was given no the corresponding lock.
1150: **
1151: ** The xShmLock method can transition between unlocked and SHARED or
1152: ** between unlocked and EXCLUSIVE. It cannot transition between SHARED
1153: ** and EXCLUSIVE.
1154: */
1155: #define SQLITE_SHM_UNLOCK 1
1156: #define SQLITE_SHM_LOCK 2
1157: #define SQLITE_SHM_SHARED 4
1158: #define SQLITE_SHM_EXCLUSIVE 8
1159:
1160: /*
1161: ** CAPI3REF: Maximum xShmLock index
1162: **
1163: ** The xShmLock method on [sqlite3_io_methods] may use values
1164: ** between 0 and this upper bound as its "offset" argument.
1165: ** The SQLite core will never attempt to acquire or release a
1166: ** lock outside of this range
1167: */
1168: #define SQLITE_SHM_NLOCK 8
1169:
1170:
1171: /*
1172: ** CAPI3REF: Initialize The SQLite Library
1173: **
1174: ** ^The sqlite3_initialize() routine initializes the
1175: ** SQLite library. ^The sqlite3_shutdown() routine
1176: ** deallocates any resources that were allocated by sqlite3_initialize().
1177: ** These routines are designed to aid in process initialization and
1178: ** shutdown on embedded systems. Workstation applications using
1179: ** SQLite normally do not need to invoke either of these routines.
1180: **
1181: ** A call to sqlite3_initialize() is an "effective" call if it is
1182: ** the first time sqlite3_initialize() is invoked during the lifetime of
1183: ** the process, or if it is the first time sqlite3_initialize() is invoked
1184: ** following a call to sqlite3_shutdown(). ^(Only an effective call
1185: ** of sqlite3_initialize() does any initialization. All other calls
1186: ** are harmless no-ops.)^
1187: **
1188: ** A call to sqlite3_shutdown() is an "effective" call if it is the first
1189: ** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only
1190: ** an effective call to sqlite3_shutdown() does any deinitialization.
1191: ** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
1192: **
1193: ** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
1194: ** is not. The sqlite3_shutdown() interface must only be called from a
1195: ** single thread. All open [database connections] must be closed and all
1196: ** other SQLite resources must be deallocated prior to invoking
1197: ** sqlite3_shutdown().
1198: **
1199: ** Among other things, ^sqlite3_initialize() will invoke
1200: ** sqlite3_os_init(). Similarly, ^sqlite3_shutdown()
1201: ** will invoke sqlite3_os_end().
1202: **
1203: ** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
1204: ** ^If for some reason, sqlite3_initialize() is unable to initialize
1205: ** the library (perhaps it is unable to allocate a needed resource such
1206: ** as a mutex) it returns an [error code] other than [SQLITE_OK].
1207: **
1208: ** ^The sqlite3_initialize() routine is called internally by many other
1209: ** SQLite interfaces so that an application usually does not need to
1210: ** invoke sqlite3_initialize() directly. For example, [sqlite3_open()]
1211: ** calls sqlite3_initialize() so the SQLite library will be automatically
1212: ** initialized when [sqlite3_open()] is called if it has not be initialized
1213: ** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
1214: ** compile-time option, then the automatic calls to sqlite3_initialize()
1215: ** are omitted and the application must call sqlite3_initialize() directly
1216: ** prior to using any other SQLite interface. For maximum portability,
1217: ** it is recommended that applications always invoke sqlite3_initialize()
1218: ** directly prior to using any other SQLite interface. Future releases
1219: ** of SQLite may require this. In other words, the behavior exhibited
1220: ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
1221: ** default behavior in some future release of SQLite.
1222: **
1223: ** The sqlite3_os_init() routine does operating-system specific
1224: ** initialization of the SQLite library. The sqlite3_os_end()
1225: ** routine undoes the effect of sqlite3_os_init(). Typical tasks
1226: ** performed by these routines include allocation or deallocation
1227: ** of static resources, initialization of global variables,
1228: ** setting up a default [sqlite3_vfs] module, or setting up
1229: ** a default configuration using [sqlite3_config()].
1230: **
1231: ** The application should never invoke either sqlite3_os_init()
1232: ** or sqlite3_os_end() directly. The application should only invoke
1233: ** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init()
1234: ** interface is called automatically by sqlite3_initialize() and
1235: ** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate
1236: ** implementations for sqlite3_os_init() and sqlite3_os_end()
1237: ** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
1238: ** When [custom builds | built for other platforms]
1239: ** (using the [SQLITE_OS_OTHER=1] compile-time
1240: ** option) the application must supply a suitable implementation for
1241: ** sqlite3_os_init() and sqlite3_os_end(). An application-supplied
1242: ** implementation of sqlite3_os_init() or sqlite3_os_end()
1243: ** must return [SQLITE_OK] on success and some other [error code] upon
1244: ** failure.
1245: */
1246: SQLITE_API int sqlite3_initialize(void);
1247: SQLITE_API int sqlite3_shutdown(void);
1248: SQLITE_API int sqlite3_os_init(void);
1249: SQLITE_API int sqlite3_os_end(void);
1250:
1251: /*
1252: ** CAPI3REF: Configuring The SQLite Library
1253: **
1254: ** The sqlite3_config() interface is used to make global configuration
1255: ** changes to SQLite in order to tune SQLite to the specific needs of
1256: ** the application. The default configuration is recommended for most
1257: ** applications and so this routine is usually not necessary. It is
1258: ** provided to support rare applications with unusual needs.
1259: **
1260: ** The sqlite3_config() interface is not threadsafe. The application
1261: ** must insure that no other SQLite interfaces are invoked by other
1262: ** threads while sqlite3_config() is running. Furthermore, sqlite3_config()
1263: ** may only be invoked prior to library initialization using
1264: ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
1265: ** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
1266: ** [sqlite3_shutdown()] then it will return SQLITE_MISUSE.
1267: ** Note, however, that ^sqlite3_config() can be called as part of the
1268: ** implementation of an application-defined [sqlite3_os_init()].
1269: **
1270: ** The first argument to sqlite3_config() is an integer
1271: ** [configuration option] that determines
1272: ** what property of SQLite is to be configured. Subsequent arguments
1273: ** vary depending on the [configuration option]
1274: ** in the first argument.
1275: **
1276: ** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
1277: ** ^If the option is unknown or SQLite is unable to set the option
1278: ** then this routine returns a non-zero [error code].
1279: */
1280: SQLITE_API int sqlite3_config(int, ...);
1281:
1282: /*
1283: ** CAPI3REF: Configure database connections
1284: **
1285: ** The sqlite3_db_config() interface is used to make configuration
1286: ** changes to a [database connection]. The interface is similar to
1287: ** [sqlite3_config()] except that the changes apply to a single
1288: ** [database connection] (specified in the first argument).
1289: **
1290: ** The second argument to sqlite3_db_config(D,V,...) is the
1291: ** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code
1292: ** that indicates what aspect of the [database connection] is being configured.
1293: ** Subsequent arguments vary depending on the configuration verb.
1294: **
1295: ** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
1296: ** the call is considered successful.
1297: */
1298: SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...);
1299:
1300: /*
1301: ** CAPI3REF: Memory Allocation Routines
1302: **
1303: ** An instance of this object defines the interface between SQLite
1304: ** and low-level memory allocation routines.
1305: **
1306: ** This object is used in only one place in the SQLite interface.
1307: ** A pointer to an instance of this object is the argument to
1308: ** [sqlite3_config()] when the configuration option is
1309: ** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].
1310: ** By creating an instance of this object
1311: ** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
1312: ** during configuration, an application can specify an alternative
1313: ** memory allocation subsystem for SQLite to use for all of its
1314: ** dynamic memory needs.
1315: **
1316: ** Note that SQLite comes with several [built-in memory allocators]
1317: ** that are perfectly adequate for the overwhelming majority of applications
1318: ** and that this object is only useful to a tiny minority of applications
1319: ** with specialized memory allocation requirements. This object is
1320: ** also used during testing of SQLite in order to specify an alternative
1321: ** memory allocator that simulates memory out-of-memory conditions in
1322: ** order to verify that SQLite recovers gracefully from such
1323: ** conditions.
1324: **
1325: ** The xMalloc, xRealloc, and xFree methods must work like the
1326: ** malloc(), realloc() and free() functions from the standard C library.
1327: ** ^SQLite guarantees that the second argument to
1328: ** xRealloc is always a value returned by a prior call to xRoundup.
1329: **
1330: ** xSize should return the allocated size of a memory allocation
1331: ** previously obtained from xMalloc or xRealloc. The allocated size
1332: ** is always at least as big as the requested size but may be larger.
1333: **
1334: ** The xRoundup method returns what would be the allocated size of
1335: ** a memory allocation given a particular requested size. Most memory
1336: ** allocators round up memory allocations at least to the next multiple
1337: ** of 8. Some allocators round up to a larger multiple or to a power of 2.
1338: ** Every memory allocation request coming in through [sqlite3_malloc()]
1339: ** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0,
1340: ** that causes the corresponding memory allocation to fail.
1341: **
1342: ** The xInit method initializes the memory allocator. (For example,
1343: ** it might allocate any require mutexes or initialize internal data
1344: ** structures. The xShutdown method is invoked (indirectly) by
1345: ** [sqlite3_shutdown()] and should deallocate any resources acquired
1346: ** by xInit. The pAppData pointer is used as the only parameter to
1347: ** xInit and xShutdown.
1348: **
1349: ** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes
1350: ** the xInit method, so the xInit method need not be threadsafe. The
1351: ** xShutdown method is only called from [sqlite3_shutdown()] so it does
1352: ** not need to be threadsafe either. For all other methods, SQLite
1353: ** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
1354: ** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
1355: ** it is by default) and so the methods are automatically serialized.
1356: ** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
1357: ** methods must be threadsafe or else make their own arrangements for
1358: ** serialization.
1359: **
1360: ** SQLite will never invoke xInit() more than once without an intervening
1361: ** call to xShutdown().
1362: */
1363: typedef struct sqlite3_mem_methods sqlite3_mem_methods;
1364: struct sqlite3_mem_methods {
1365: void *(*xMalloc)(int); /* Memory allocation function */
1366: void (*xFree)(void*); /* Free a prior allocation */
1367: void *(*xRealloc)(void*,int); /* Resize an allocation */
1368: int (*xSize)(void*); /* Return the size of an allocation */
1369: int (*xRoundup)(int); /* Round up request size to allocation size */
1370: int (*xInit)(void*); /* Initialize the memory allocator */
1371: void (*xShutdown)(void*); /* Deinitialize the memory allocator */
1372: void *pAppData; /* Argument to xInit() and xShutdown() */
1373: };
1374:
1375: /*
1376: ** CAPI3REF: Configuration Options
1377: ** KEYWORDS: {configuration option}
1378: **
1379: ** These constants are the available integer configuration options that
1380: ** can be passed as the first argument to the [sqlite3_config()] interface.
1381: **
1382: ** New configuration options may be added in future releases of SQLite.
1383: ** Existing configuration options might be discontinued. Applications
1384: ** should check the return code from [sqlite3_config()] to make sure that
1385: ** the call worked. The [sqlite3_config()] interface will return a
1386: ** non-zero [error code] if a discontinued or unsupported configuration option
1387: ** is invoked.
1388: **
1389: ** <dl>
1390: ** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
1391: ** <dd>There are no arguments to this option. ^This option sets the
1392: ** [threading mode] to Single-thread. In other words, it disables
1393: ** all mutexing and puts SQLite into a mode where it can only be used
1394: ** by a single thread. ^If SQLite is compiled with
1395: ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1396: ** it is not possible to change the [threading mode] from its default
1397: ** value of Single-thread and so [sqlite3_config()] will return
1398: ** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
1399: ** configuration option.</dd>
1400: **
1401: ** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt>
1402: ** <dd>There are no arguments to this option. ^This option sets the
1403: ** [threading mode] to Multi-thread. In other words, it disables
1404: ** mutexing on [database connection] and [prepared statement] objects.
1405: ** The application is responsible for serializing access to
1406: ** [database connections] and [prepared statements]. But other mutexes
1407: ** are enabled so that SQLite will be safe to use in a multi-threaded
1408: ** environment as long as no two threads attempt to use the same
1409: ** [database connection] at the same time. ^If SQLite is compiled with
1410: ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1411: ** it is not possible to set the Multi-thread [threading mode] and
1412: ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1413: ** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
1414: **
1415: ** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt>
1416: ** <dd>There are no arguments to this option. ^This option sets the
1417: ** [threading mode] to Serialized. In other words, this option enables
1418: ** all mutexes including the recursive
1419: ** mutexes on [database connection] and [prepared statement] objects.
1420: ** In this mode (which is the default when SQLite is compiled with
1421: ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
1422: ** to [database connections] and [prepared statements] so that the
1423: ** application is free to use the same [database connection] or the
1424: ** same [prepared statement] in different threads at the same time.
1425: ** ^If SQLite is compiled with
1426: ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1427: ** it is not possible to set the Serialized [threading mode] and
1428: ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1429: ** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
1430: **
1431: ** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt>
1432: ** <dd> ^(This option takes a single argument which is a pointer to an
1433: ** instance of the [sqlite3_mem_methods] structure. The argument specifies
1434: ** alternative low-level memory allocation routines to be used in place of
1435: ** the memory allocation routines built into SQLite.)^ ^SQLite makes
1436: ** its own private copy of the content of the [sqlite3_mem_methods] structure
1437: ** before the [sqlite3_config()] call returns.</dd>
1438: **
1439: ** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt>
1440: ** <dd> ^(This option takes a single argument which is a pointer to an
1441: ** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods]
1442: ** structure is filled with the currently defined memory allocation routines.)^
1443: ** This option can be used to overload the default memory allocation
1444: ** routines with a wrapper that simulations memory allocation failure or
1445: ** tracks memory usage, for example. </dd>
1446: **
1447: ** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt>
1448: ** <dd> ^This option takes single argument of type int, interpreted as a
1449: ** boolean, which enables or disables the collection of memory allocation
1450: ** statistics. ^(When memory allocation statistics are disabled, the
1451: ** following SQLite interfaces become non-operational:
1452: ** <ul>
1453: ** <li> [sqlite3_memory_used()]
1454: ** <li> [sqlite3_memory_highwater()]
1455: ** <li> [sqlite3_soft_heap_limit64()]
1456: ** <li> [sqlite3_status()]
1457: ** </ul>)^
1458: ** ^Memory allocation statistics are enabled by default unless SQLite is
1459: ** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
1460: ** allocation statistics are disabled by default.
1461: ** </dd>
1462: **
1463: ** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt>
1464: ** <dd> ^This option specifies a static memory buffer that SQLite can use for
1465: ** scratch memory. There are three arguments: A pointer an 8-byte
1466: ** aligned memory buffer from which the scratch allocations will be
1467: ** drawn, the size of each scratch allocation (sz),
1468: ** and the maximum number of scratch allocations (N). The sz
1469: ** argument must be a multiple of 16.
1470: ** The first argument must be a pointer to an 8-byte aligned buffer
1471: ** of at least sz*N bytes of memory.
1472: ** ^SQLite will use no more than two scratch buffers per thread. So
1473: ** N should be set to twice the expected maximum number of threads.
1474: ** ^SQLite will never require a scratch buffer that is more than 6
1475: ** times the database page size. ^If SQLite needs needs additional
1476: ** scratch memory beyond what is provided by this configuration option, then
1477: ** [sqlite3_malloc()] will be used to obtain the memory needed.</dd>
1478: **
1479: ** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>
1480: ** <dd> ^This option specifies a static memory buffer that SQLite can use for
1481: ** the database page cache with the default page cache implementation.
1482: ** This configuration should not be used if an application-define page
1483: ** cache implementation is loaded using the SQLITE_CONFIG_PCACHE2 option.
1484: ** There are three arguments to this option: A pointer to 8-byte aligned
1485: ** memory, the size of each page buffer (sz), and the number of pages (N).
1486: ** The sz argument should be the size of the largest database page
1487: ** (a power of two between 512 and 32768) plus a little extra for each
1488: ** page header. ^The page header size is 20 to 40 bytes depending on
1489: ** the host architecture. ^It is harmless, apart from the wasted memory,
1490: ** to make sz a little too large. The first
1491: ** argument should point to an allocation of at least sz*N bytes of memory.
1492: ** ^SQLite will use the memory provided by the first argument to satisfy its
1493: ** memory needs for the first N pages that it adds to cache. ^If additional
1494: ** page cache memory is needed beyond what is provided by this option, then
1495: ** SQLite goes to [sqlite3_malloc()] for the additional storage space.
1496: ** The pointer in the first argument must
1497: ** be aligned to an 8-byte boundary or subsequent behavior of SQLite
1498: ** will be undefined.</dd>
1499: **
1500: ** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt>
1501: ** <dd> ^This option specifies a static memory buffer that SQLite will use
1502: ** for all of its dynamic memory allocation needs beyond those provided
1503: ** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE].
1504: ** There are three arguments: An 8-byte aligned pointer to the memory,
1505: ** the number of bytes in the memory buffer, and the minimum allocation size.
1506: ** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
1507: ** to using its default memory allocator (the system malloc() implementation),
1508: ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the
1509: ** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or
1510: ** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory
1511: ** allocator is engaged to handle all of SQLites memory allocation needs.
1512: ** The first pointer (the memory pointer) must be aligned to an 8-byte
1513: ** boundary or subsequent behavior of SQLite will be undefined.
1514: ** The minimum allocation size is capped at 2**12. Reasonable values
1515: ** for the minimum allocation size are 2**5 through 2**8.</dd>
1516: **
1517: ** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt>
1518: ** <dd> ^(This option takes a single argument which is a pointer to an
1519: ** instance of the [sqlite3_mutex_methods] structure. The argument specifies
1520: ** alternative low-level mutex routines to be used in place
1521: ** the mutex routines built into SQLite.)^ ^SQLite makes a copy of the
1522: ** content of the [sqlite3_mutex_methods] structure before the call to
1523: ** [sqlite3_config()] returns. ^If SQLite is compiled with
1524: ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1525: ** the entire mutexing subsystem is omitted from the build and hence calls to
1526: ** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
1527: ** return [SQLITE_ERROR].</dd>
1528: **
1529: ** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt>
1530: ** <dd> ^(This option takes a single argument which is a pointer to an
1531: ** instance of the [sqlite3_mutex_methods] structure. The
1532: ** [sqlite3_mutex_methods]
1533: ** structure is filled with the currently defined mutex routines.)^
1534: ** This option can be used to overload the default mutex allocation
1535: ** routines with a wrapper used to track mutex usage for performance
1536: ** profiling or testing, for example. ^If SQLite is compiled with
1537: ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1538: ** the entire mutexing subsystem is omitted from the build and hence calls to
1539: ** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
1540: ** return [SQLITE_ERROR].</dd>
1541: **
1542: ** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt>
1543: ** <dd> ^(This option takes two arguments that determine the default
1544: ** memory allocation for the lookaside memory allocator on each
1545: ** [database connection]. The first argument is the
1546: ** size of each lookaside buffer slot and the second is the number of
1547: ** slots allocated to each database connection.)^ ^(This option sets the
1548: ** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
1549: ** verb to [sqlite3_db_config()] can be used to change the lookaside
1550: ** configuration on individual connections.)^ </dd>
1551: **
1552: ** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt>
1553: ** <dd> ^(This option takes a single argument which is a pointer to
1554: ** an [sqlite3_pcache_methods2] object. This object specifies the interface
1555: ** to a custom page cache implementation.)^ ^SQLite makes a copy of the
1556: ** object and uses it for page cache memory allocations.</dd>
1557: **
1558: ** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt>
1559: ** <dd> ^(This option takes a single argument which is a pointer to an
1560: ** [sqlite3_pcache_methods2] object. SQLite copies of the current
1561: ** page cache implementation into that object.)^ </dd>
1562: **
1563: ** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>
1564: ** <dd> ^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
1565: ** function with a call signature of void(*)(void*,int,const char*),
1566: ** and a pointer to void. ^If the function pointer is not NULL, it is
1567: ** invoked by [sqlite3_log()] to process each logging event. ^If the
1568: ** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
1569: ** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
1570: ** passed through as the first parameter to the application-defined logger
1571: ** function whenever that function is invoked. ^The second parameter to
1572: ** the logger function is a copy of the first parameter to the corresponding
1573: ** [sqlite3_log()] call and is intended to be a [result code] or an
1574: ** [extended result code]. ^The third parameter passed to the logger is
1575: ** log message after formatting via [sqlite3_snprintf()].
1576: ** The SQLite logging interface is not reentrant; the logger function
1577: ** supplied by the application must not invoke any SQLite interface.
1578: ** In a multi-threaded application, the application-defined logger
1579: ** function must be threadsafe. </dd>
1580: **
1581: ** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI
1582: ** <dd> This option takes a single argument of type int. If non-zero, then
1583: ** URI handling is globally enabled. If the parameter is zero, then URI handling
1584: ** is globally disabled. If URI handling is globally enabled, all filenames
1585: ** passed to [sqlite3_open()], [sqlite3_open_v2()], [sqlite3_open16()] or
1586: ** specified as part of [ATTACH] commands are interpreted as URIs, regardless
1587: ** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
1588: ** connection is opened. If it is globally disabled, filenames are
1589: ** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
1590: ** database connection is opened. By default, URI handling is globally
1591: ** disabled. The default value may be changed by compiling with the
1592: ** [SQLITE_USE_URI] symbol defined.
1593: **
1.3 ! misho 1594: ** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN
! 1595: ** <dd> This option takes a single integer argument which is interpreted as
! 1596: ** a boolean in order to enable or disable the use of covering indices for
! 1597: ** full table scans in the query optimizer. The default setting is determined
! 1598: ** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on"
! 1599: ** if that compile-time option is omitted.
! 1600: ** The ability to disable the use of covering indices for full table scans
! 1601: ** is because some incorrectly coded legacy applications might malfunction
! 1602: ** malfunction when the optimization is enabled. Providing the ability to
! 1603: ** disable the optimization allows the older, buggy application code to work
! 1604: ** without change even with newer versions of SQLite.
! 1605: **
1.2 misho 1606: ** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]]
1.3 ! misho 1607: ** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE
1.2 misho 1608: ** <dd> These options are obsolete and should not be used by new code.
1609: ** They are retained for backwards compatibility but are now no-ops.
1610: ** </dl>
1.3 ! misho 1611: **
! 1612: ** [[SQLITE_CONFIG_SQLLOG]]
! 1613: ** <dt>SQLITE_CONFIG_SQLLOG
! 1614: ** <dd>This option is only available if sqlite is compiled with the
! 1615: ** SQLITE_ENABLE_SQLLOG pre-processor macro defined. The first argument should
! 1616: ** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int).
! 1617: ** The second should be of type (void*). The callback is invoked by the library
! 1618: ** in three separate circumstances, identified by the value passed as the
! 1619: ** fourth parameter. If the fourth parameter is 0, then the database connection
! 1620: ** passed as the second argument has just been opened. The third argument
! 1621: ** points to a buffer containing the name of the main database file. If the
! 1622: ** fourth parameter is 1, then the SQL statement that the third parameter
! 1623: ** points to has just been executed. Or, if the fourth parameter is 2, then
! 1624: ** the connection being passed as the second parameter is being closed. The
! 1625: ** third parameter is passed NULL In this case.
! 1626: ** </dl>
1.2 misho 1627: */
1628: #define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */
1629: #define SQLITE_CONFIG_MULTITHREAD 2 /* nil */
1630: #define SQLITE_CONFIG_SERIALIZED 3 /* nil */
1631: #define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */
1632: #define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */
1633: #define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */
1634: #define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */
1635: #define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */
1636: #define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */
1637: #define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */
1638: #define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */
1639: /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */
1640: #define SQLITE_CONFIG_LOOKASIDE 13 /* int int */
1641: #define SQLITE_CONFIG_PCACHE 14 /* no-op */
1642: #define SQLITE_CONFIG_GETPCACHE 15 /* no-op */
1643: #define SQLITE_CONFIG_LOG 16 /* xFunc, void* */
1644: #define SQLITE_CONFIG_URI 17 /* int */
1645: #define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */
1646: #define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */
1.3 ! misho 1647: #define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */
! 1648: #define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */
1.2 misho 1649:
1650: /*
1651: ** CAPI3REF: Database Connection Configuration Options
1652: **
1653: ** These constants are the available integer configuration options that
1654: ** can be passed as the second argument to the [sqlite3_db_config()] interface.
1655: **
1656: ** New configuration options may be added in future releases of SQLite.
1657: ** Existing configuration options might be discontinued. Applications
1658: ** should check the return code from [sqlite3_db_config()] to make sure that
1659: ** the call worked. ^The [sqlite3_db_config()] interface will return a
1660: ** non-zero [error code] if a discontinued or unsupported configuration option
1661: ** is invoked.
1662: **
1663: ** <dl>
1664: ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
1665: ** <dd> ^This option takes three additional arguments that determine the
1666: ** [lookaside memory allocator] configuration for the [database connection].
1667: ** ^The first argument (the third parameter to [sqlite3_db_config()] is a
1668: ** pointer to a memory buffer to use for lookaside memory.
1669: ** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
1670: ** may be NULL in which case SQLite will allocate the
1671: ** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
1672: ** size of each lookaside buffer slot. ^The third argument is the number of
1673: ** slots. The size of the buffer in the first argument must be greater than
1674: ** or equal to the product of the second and third arguments. The buffer
1675: ** must be aligned to an 8-byte boundary. ^If the second argument to
1676: ** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
1677: ** rounded down to the next smaller multiple of 8. ^(The lookaside memory
1678: ** configuration for a database connection can only be changed when that
1679: ** connection is not currently using lookaside memory, or in other words
1680: ** when the "current value" returned by
1681: ** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero.
1682: ** Any attempt to change the lookaside memory configuration when lookaside
1683: ** memory is in use leaves the configuration unchanged and returns
1684: ** [SQLITE_BUSY].)^</dd>
1685: **
1686: ** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
1687: ** <dd> ^This option is used to enable or disable the enforcement of
1688: ** [foreign key constraints]. There should be two additional arguments.
1689: ** The first argument is an integer which is 0 to disable FK enforcement,
1690: ** positive to enable FK enforcement or negative to leave FK enforcement
1691: ** unchanged. The second parameter is a pointer to an integer into which
1692: ** is written 0 or 1 to indicate whether FK enforcement is off or on
1693: ** following this call. The second parameter may be a NULL pointer, in
1694: ** which case the FK enforcement setting is not reported back. </dd>
1695: **
1696: ** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
1697: ** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
1698: ** There should be two additional arguments.
1699: ** The first argument is an integer which is 0 to disable triggers,
1700: ** positive to enable triggers or negative to leave the setting unchanged.
1701: ** The second parameter is a pointer to an integer into which
1702: ** is written 0 or 1 to indicate whether triggers are disabled or enabled
1703: ** following this call. The second parameter may be a NULL pointer, in
1704: ** which case the trigger setting is not reported back. </dd>
1705: **
1706: ** </dl>
1707: */
1708: #define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */
1709: #define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */
1710: #define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */
1711:
1712:
1713: /*
1714: ** CAPI3REF: Enable Or Disable Extended Result Codes
1715: **
1716: ** ^The sqlite3_extended_result_codes() routine enables or disables the
1717: ** [extended result codes] feature of SQLite. ^The extended result
1718: ** codes are disabled by default for historical compatibility.
1719: */
1720: SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff);
1721:
1722: /*
1723: ** CAPI3REF: Last Insert Rowid
1724: **
1725: ** ^Each entry in an SQLite table has a unique 64-bit signed
1726: ** integer key called the [ROWID | "rowid"]. ^The rowid is always available
1727: ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
1728: ** names are not also used by explicitly declared columns. ^If
1729: ** the table has a column of type [INTEGER PRIMARY KEY] then that column
1730: ** is another alias for the rowid.
1731: **
1732: ** ^This routine returns the [rowid] of the most recent
1733: ** successful [INSERT] into the database from the [database connection]
1734: ** in the first argument. ^As of SQLite version 3.7.7, this routines
1735: ** records the last insert rowid of both ordinary tables and [virtual tables].
1736: ** ^If no successful [INSERT]s
1737: ** have ever occurred on that database connection, zero is returned.
1738: **
1739: ** ^(If an [INSERT] occurs within a trigger or within a [virtual table]
1740: ** method, then this routine will return the [rowid] of the inserted
1741: ** row as long as the trigger or virtual table method is running.
1742: ** But once the trigger or virtual table method ends, the value returned
1743: ** by this routine reverts to what it was before the trigger or virtual
1744: ** table method began.)^
1745: **
1746: ** ^An [INSERT] that fails due to a constraint violation is not a
1747: ** successful [INSERT] and does not change the value returned by this
1748: ** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
1749: ** and INSERT OR ABORT make no changes to the return value of this
1750: ** routine when their insertion fails. ^(When INSERT OR REPLACE
1751: ** encounters a constraint violation, it does not fail. The
1752: ** INSERT continues to completion after deleting rows that caused
1753: ** the constraint problem so INSERT OR REPLACE will always change
1754: ** the return value of this interface.)^
1755: **
1756: ** ^For the purposes of this routine, an [INSERT] is considered to
1757: ** be successful even if it is subsequently rolled back.
1758: **
1759: ** This function is accessible to SQL statements via the
1760: ** [last_insert_rowid() SQL function].
1761: **
1762: ** If a separate thread performs a new [INSERT] on the same
1763: ** database connection while the [sqlite3_last_insert_rowid()]
1764: ** function is running and thus changes the last insert [rowid],
1765: ** then the value returned by [sqlite3_last_insert_rowid()] is
1766: ** unpredictable and might not equal either the old or the new
1767: ** last insert [rowid].
1768: */
1769: SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
1770:
1771: /*
1772: ** CAPI3REF: Count The Number Of Rows Modified
1773: **
1774: ** ^This function returns the number of database rows that were changed
1775: ** or inserted or deleted by the most recently completed SQL statement
1776: ** on the [database connection] specified by the first parameter.
1777: ** ^(Only changes that are directly specified by the [INSERT], [UPDATE],
1778: ** or [DELETE] statement are counted. Auxiliary changes caused by
1779: ** triggers or [foreign key actions] are not counted.)^ Use the
1780: ** [sqlite3_total_changes()] function to find the total number of changes
1781: ** including changes caused by triggers and foreign key actions.
1782: **
1783: ** ^Changes to a view that are simulated by an [INSTEAD OF trigger]
1784: ** are not counted. Only real table changes are counted.
1785: **
1786: ** ^(A "row change" is a change to a single row of a single table
1787: ** caused by an INSERT, DELETE, or UPDATE statement. Rows that
1788: ** are changed as side effects of [REPLACE] constraint resolution,
1789: ** rollback, ABORT processing, [DROP TABLE], or by any other
1790: ** mechanisms do not count as direct row changes.)^
1791: **
1792: ** A "trigger context" is a scope of execution that begins and
1793: ** ends with the script of a [CREATE TRIGGER | trigger].
1794: ** Most SQL statements are
1795: ** evaluated outside of any trigger. This is the "top level"
1796: ** trigger context. If a trigger fires from the top level, a
1797: ** new trigger context is entered for the duration of that one
1798: ** trigger. Subtriggers create subcontexts for their duration.
1799: **
1800: ** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does
1801: ** not create a new trigger context.
1802: **
1803: ** ^This function returns the number of direct row changes in the
1804: ** most recent INSERT, UPDATE, or DELETE statement within the same
1805: ** trigger context.
1806: **
1807: ** ^Thus, when called from the top level, this function returns the
1808: ** number of changes in the most recent INSERT, UPDATE, or DELETE
1809: ** that also occurred at the top level. ^(Within the body of a trigger,
1810: ** the sqlite3_changes() interface can be called to find the number of
1811: ** changes in the most recently completed INSERT, UPDATE, or DELETE
1812: ** statement within the body of the same trigger.
1813: ** However, the number returned does not include changes
1814: ** caused by subtriggers since those have their own context.)^
1815: **
1816: ** See also the [sqlite3_total_changes()] interface, the
1817: ** [count_changes pragma], and the [changes() SQL function].
1818: **
1819: ** If a separate thread makes changes on the same database connection
1820: ** while [sqlite3_changes()] is running then the value returned
1821: ** is unpredictable and not meaningful.
1822: */
1823: SQLITE_API int sqlite3_changes(sqlite3*);
1824:
1825: /*
1826: ** CAPI3REF: Total Number Of Rows Modified
1827: **
1828: ** ^This function returns the number of row changes caused by [INSERT],
1829: ** [UPDATE] or [DELETE] statements since the [database connection] was opened.
1830: ** ^(The count returned by sqlite3_total_changes() includes all changes
1831: ** from all [CREATE TRIGGER | trigger] contexts and changes made by
1832: ** [foreign key actions]. However,
1833: ** the count does not include changes used to implement [REPLACE] constraints,
1834: ** do rollbacks or ABORT processing, or [DROP TABLE] processing. The
1835: ** count does not include rows of views that fire an [INSTEAD OF trigger],
1836: ** though if the INSTEAD OF trigger makes changes of its own, those changes
1837: ** are counted.)^
1838: ** ^The sqlite3_total_changes() function counts the changes as soon as
1839: ** the statement that makes them is completed (when the statement handle
1840: ** is passed to [sqlite3_reset()] or [sqlite3_finalize()]).
1841: **
1842: ** See also the [sqlite3_changes()] interface, the
1843: ** [count_changes pragma], and the [total_changes() SQL function].
1844: **
1845: ** If a separate thread makes changes on the same database connection
1846: ** while [sqlite3_total_changes()] is running then the value
1847: ** returned is unpredictable and not meaningful.
1848: */
1849: SQLITE_API int sqlite3_total_changes(sqlite3*);
1850:
1851: /*
1852: ** CAPI3REF: Interrupt A Long-Running Query
1853: **
1854: ** ^This function causes any pending database operation to abort and
1855: ** return at its earliest opportunity. This routine is typically
1856: ** called in response to a user action such as pressing "Cancel"
1857: ** or Ctrl-C where the user wants a long query operation to halt
1858: ** immediately.
1859: **
1860: ** ^It is safe to call this routine from a thread different from the
1861: ** thread that is currently running the database operation. But it
1862: ** is not safe to call this routine with a [database connection] that
1863: ** is closed or might close before sqlite3_interrupt() returns.
1864: **
1865: ** ^If an SQL operation is very nearly finished at the time when
1866: ** sqlite3_interrupt() is called, then it might not have an opportunity
1867: ** to be interrupted and might continue to completion.
1868: **
1869: ** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
1870: ** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
1871: ** that is inside an explicit transaction, then the entire transaction
1872: ** will be rolled back automatically.
1873: **
1874: ** ^The sqlite3_interrupt(D) call is in effect until all currently running
1875: ** SQL statements on [database connection] D complete. ^Any new SQL statements
1876: ** that are started after the sqlite3_interrupt() call and before the
1877: ** running statements reaches zero are interrupted as if they had been
1878: ** running prior to the sqlite3_interrupt() call. ^New SQL statements
1879: ** that are started after the running statement count reaches zero are
1880: ** not effected by the sqlite3_interrupt().
1881: ** ^A call to sqlite3_interrupt(D) that occurs when there are no running
1882: ** SQL statements is a no-op and has no effect on SQL statements
1883: ** that are started after the sqlite3_interrupt() call returns.
1884: **
1885: ** If the database connection closes while [sqlite3_interrupt()]
1886: ** is running then bad things will likely happen.
1887: */
1888: SQLITE_API void sqlite3_interrupt(sqlite3*);
1889:
1890: /*
1891: ** CAPI3REF: Determine If An SQL Statement Is Complete
1892: **
1893: ** These routines are useful during command-line input to determine if the
1894: ** currently entered text seems to form a complete SQL statement or
1895: ** if additional input is needed before sending the text into
1896: ** SQLite for parsing. ^These routines return 1 if the input string
1897: ** appears to be a complete SQL statement. ^A statement is judged to be
1898: ** complete if it ends with a semicolon token and is not a prefix of a
1899: ** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within
1900: ** string literals or quoted identifier names or comments are not
1901: ** independent tokens (they are part of the token in which they are
1902: ** embedded) and thus do not count as a statement terminator. ^Whitespace
1903: ** and comments that follow the final semicolon are ignored.
1904: **
1905: ** ^These routines return 0 if the statement is incomplete. ^If a
1906: ** memory allocation fails, then SQLITE_NOMEM is returned.
1907: **
1908: ** ^These routines do not parse the SQL statements thus
1909: ** will not detect syntactically incorrect SQL.
1910: **
1911: ** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior
1912: ** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
1913: ** automatically by sqlite3_complete16(). If that initialization fails,
1914: ** then the return value from sqlite3_complete16() will be non-zero
1915: ** regardless of whether or not the input SQL is complete.)^
1916: **
1917: ** The input to [sqlite3_complete()] must be a zero-terminated
1918: ** UTF-8 string.
1919: **
1920: ** The input to [sqlite3_complete16()] must be a zero-terminated
1921: ** UTF-16 string in native byte order.
1922: */
1923: SQLITE_API int sqlite3_complete(const char *sql);
1924: SQLITE_API int sqlite3_complete16(const void *sql);
1925:
1926: /*
1927: ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
1928: **
1929: ** ^This routine sets a callback function that might be invoked whenever
1930: ** an attempt is made to open a database table that another thread
1931: ** or process has locked.
1932: **
1933: ** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]
1934: ** is returned immediately upon encountering the lock. ^If the busy callback
1935: ** is not NULL, then the callback might be invoked with two arguments.
1936: **
1937: ** ^The first argument to the busy handler is a copy of the void* pointer which
1938: ** is the third argument to sqlite3_busy_handler(). ^The second argument to
1939: ** the busy handler callback is the number of times that the busy handler has
1940: ** been invoked for this locking event. ^If the
1941: ** busy callback returns 0, then no additional attempts are made to
1942: ** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned.
1943: ** ^If the callback returns non-zero, then another attempt
1944: ** is made to open the database for reading and the cycle repeats.
1945: **
1946: ** The presence of a busy handler does not guarantee that it will be invoked
1947: ** when there is lock contention. ^If SQLite determines that invoking the busy
1948: ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
1949: ** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler.
1950: ** Consider a scenario where one process is holding a read lock that
1951: ** it is trying to promote to a reserved lock and
1952: ** a second process is holding a reserved lock that it is trying
1953: ** to promote to an exclusive lock. The first process cannot proceed
1954: ** because it is blocked by the second and the second process cannot
1955: ** proceed because it is blocked by the first. If both processes
1956: ** invoke the busy handlers, neither will make any progress. Therefore,
1957: ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
1958: ** will induce the first process to release its read lock and allow
1959: ** the second process to proceed.
1960: **
1961: ** ^The default busy callback is NULL.
1962: **
1963: ** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED]
1964: ** when SQLite is in the middle of a large transaction where all the
1965: ** changes will not fit into the in-memory cache. SQLite will
1966: ** already hold a RESERVED lock on the database file, but it needs
1967: ** to promote this lock to EXCLUSIVE so that it can spill cache
1968: ** pages into the database file without harm to concurrent
1969: ** readers. ^If it is unable to promote the lock, then the in-memory
1970: ** cache will be left in an inconsistent state and so the error
1971: ** code is promoted from the relatively benign [SQLITE_BUSY] to
1972: ** the more severe [SQLITE_IOERR_BLOCKED]. ^This error code promotion
1973: ** forces an automatic rollback of the changes. See the
1974: ** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError">
1975: ** CorruptionFollowingBusyError</a> wiki page for a discussion of why
1976: ** this is important.
1977: **
1978: ** ^(There can only be a single busy handler defined for each
1979: ** [database connection]. Setting a new busy handler clears any
1980: ** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()]
1981: ** will also set or clear the busy handler.
1982: **
1983: ** The busy callback should not take any actions which modify the
1984: ** database connection that invoked the busy handler. Any such actions
1985: ** result in undefined behavior.
1986: **
1987: ** A busy handler must not close the database connection
1988: ** or [prepared statement] that invoked the busy handler.
1989: */
1990: SQLITE_API int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*);
1991:
1992: /*
1993: ** CAPI3REF: Set A Busy Timeout
1994: **
1995: ** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
1996: ** for a specified amount of time when a table is locked. ^The handler
1997: ** will sleep multiple times until at least "ms" milliseconds of sleeping
1998: ** have accumulated. ^After at least "ms" milliseconds of sleeping,
1999: ** the handler returns 0 which causes [sqlite3_step()] to return
2000: ** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED].
2001: **
2002: ** ^Calling this routine with an argument less than or equal to zero
2003: ** turns off all busy handlers.
2004: **
2005: ** ^(There can only be a single busy handler for a particular
2006: ** [database connection] any any given moment. If another busy handler
2007: ** was defined (using [sqlite3_busy_handler()]) prior to calling
2008: ** this routine, that other busy handler is cleared.)^
2009: */
2010: SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms);
2011:
2012: /*
2013: ** CAPI3REF: Convenience Routines For Running Queries
2014: **
2015: ** This is a legacy interface that is preserved for backwards compatibility.
2016: ** Use of this interface is not recommended.
2017: **
2018: ** Definition: A <b>result table</b> is memory data structure created by the
2019: ** [sqlite3_get_table()] interface. A result table records the
2020: ** complete query results from one or more queries.
2021: **
2022: ** The table conceptually has a number of rows and columns. But
2023: ** these numbers are not part of the result table itself. These
2024: ** numbers are obtained separately. Let N be the number of rows
2025: ** and M be the number of columns.
2026: **
2027: ** A result table is an array of pointers to zero-terminated UTF-8 strings.
2028: ** There are (N+1)*M elements in the array. The first M pointers point
2029: ** to zero-terminated strings that contain the names of the columns.
2030: ** The remaining entries all point to query results. NULL values result
2031: ** in NULL pointers. All other values are in their UTF-8 zero-terminated
2032: ** string representation as returned by [sqlite3_column_text()].
2033: **
2034: ** A result table might consist of one or more memory allocations.
2035: ** It is not safe to pass a result table directly to [sqlite3_free()].
2036: ** A result table should be deallocated using [sqlite3_free_table()].
2037: **
2038: ** ^(As an example of the result table format, suppose a query result
2039: ** is as follows:
2040: **
2041: ** <blockquote><pre>
2042: ** Name | Age
2043: ** -----------------------
2044: ** Alice | 43
2045: ** Bob | 28
2046: ** Cindy | 21
2047: ** </pre></blockquote>
2048: **
2049: ** There are two column (M==2) and three rows (N==3). Thus the
2050: ** result table has 8 entries. Suppose the result table is stored
2051: ** in an array names azResult. Then azResult holds this content:
2052: **
2053: ** <blockquote><pre>
2054: ** azResult[0] = "Name";
2055: ** azResult[1] = "Age";
2056: ** azResult[2] = "Alice";
2057: ** azResult[3] = "43";
2058: ** azResult[4] = "Bob";
2059: ** azResult[5] = "28";
2060: ** azResult[6] = "Cindy";
2061: ** azResult[7] = "21";
2062: ** </pre></blockquote>)^
2063: **
2064: ** ^The sqlite3_get_table() function evaluates one or more
2065: ** semicolon-separated SQL statements in the zero-terminated UTF-8
2066: ** string of its 2nd parameter and returns a result table to the
2067: ** pointer given in its 3rd parameter.
2068: **
2069: ** After the application has finished with the result from sqlite3_get_table(),
2070: ** it must pass the result table pointer to sqlite3_free_table() in order to
2071: ** release the memory that was malloced. Because of the way the
2072: ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
2073: ** function must not try to call [sqlite3_free()] directly. Only
2074: ** [sqlite3_free_table()] is able to release the memory properly and safely.
2075: **
2076: ** The sqlite3_get_table() interface is implemented as a wrapper around
2077: ** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access
2078: ** to any internal data structures of SQLite. It uses only the public
2079: ** interface defined here. As a consequence, errors that occur in the
2080: ** wrapper layer outside of the internal [sqlite3_exec()] call are not
2081: ** reflected in subsequent calls to [sqlite3_errcode()] or
2082: ** [sqlite3_errmsg()].
2083: */
2084: SQLITE_API int sqlite3_get_table(
2085: sqlite3 *db, /* An open database */
2086: const char *zSql, /* SQL to be evaluated */
2087: char ***pazResult, /* Results of the query */
2088: int *pnRow, /* Number of result rows written here */
2089: int *pnColumn, /* Number of result columns written here */
2090: char **pzErrmsg /* Error msg written here */
2091: );
2092: SQLITE_API void sqlite3_free_table(char **result);
2093:
2094: /*
2095: ** CAPI3REF: Formatted String Printing Functions
2096: **
2097: ** These routines are work-alikes of the "printf()" family of functions
2098: ** from the standard C library.
2099: **
2100: ** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
2101: ** results into memory obtained from [sqlite3_malloc()].
2102: ** The strings returned by these two routines should be
2103: ** released by [sqlite3_free()]. ^Both routines return a
2104: ** NULL pointer if [sqlite3_malloc()] is unable to allocate enough
2105: ** memory to hold the resulting string.
2106: **
2107: ** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
2108: ** the standard C library. The result is written into the
2109: ** buffer supplied as the second parameter whose size is given by
2110: ** the first parameter. Note that the order of the
2111: ** first two parameters is reversed from snprintf().)^ This is an
2112: ** historical accident that cannot be fixed without breaking
2113: ** backwards compatibility. ^(Note also that sqlite3_snprintf()
2114: ** returns a pointer to its buffer instead of the number of
2115: ** characters actually written into the buffer.)^ We admit that
2116: ** the number of characters written would be a more useful return
2117: ** value but we cannot change the implementation of sqlite3_snprintf()
2118: ** now without breaking compatibility.
2119: **
2120: ** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
2121: ** guarantees that the buffer is always zero-terminated. ^The first
2122: ** parameter "n" is the total size of the buffer, including space for
2123: ** the zero terminator. So the longest string that can be completely
2124: ** written will be n-1 characters.
2125: **
2126: ** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
2127: **
2128: ** These routines all implement some additional formatting
2129: ** options that are useful for constructing SQL statements.
2130: ** All of the usual printf() formatting options apply. In addition, there
2131: ** is are "%q", "%Q", and "%z" options.
2132: **
2133: ** ^(The %q option works like %s in that it substitutes a nul-terminated
2134: ** string from the argument list. But %q also doubles every '\'' character.
2135: ** %q is designed for use inside a string literal.)^ By doubling each '\''
2136: ** character it escapes that character and allows it to be inserted into
2137: ** the string.
2138: **
2139: ** For example, assume the string variable zText contains text as follows:
2140: **
2141: ** <blockquote><pre>
2142: ** char *zText = "It's a happy day!";
2143: ** </pre></blockquote>
2144: **
2145: ** One can use this text in an SQL statement as follows:
2146: **
2147: ** <blockquote><pre>
2148: ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText);
2149: ** sqlite3_exec(db, zSQL, 0, 0, 0);
2150: ** sqlite3_free(zSQL);
2151: ** </pre></blockquote>
2152: **
2153: ** Because the %q format string is used, the '\'' character in zText
2154: ** is escaped and the SQL generated is as follows:
2155: **
2156: ** <blockquote><pre>
2157: ** INSERT INTO table1 VALUES('It''s a happy day!')
2158: ** </pre></blockquote>
2159: **
2160: ** This is correct. Had we used %s instead of %q, the generated SQL
2161: ** would have looked like this:
2162: **
2163: ** <blockquote><pre>
2164: ** INSERT INTO table1 VALUES('It's a happy day!');
2165: ** </pre></blockquote>
2166: **
2167: ** This second example is an SQL syntax error. As a general rule you should
2168: ** always use %q instead of %s when inserting text into a string literal.
2169: **
2170: ** ^(The %Q option works like %q except it also adds single quotes around
2171: ** the outside of the total string. Additionally, if the parameter in the
2172: ** argument list is a NULL pointer, %Q substitutes the text "NULL" (without
2173: ** single quotes).)^ So, for example, one could say:
2174: **
2175: ** <blockquote><pre>
2176: ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText);
2177: ** sqlite3_exec(db, zSQL, 0, 0, 0);
2178: ** sqlite3_free(zSQL);
2179: ** </pre></blockquote>
2180: **
2181: ** The code above will render a correct SQL statement in the zSQL
2182: ** variable even if the zText variable is a NULL pointer.
2183: **
2184: ** ^(The "%z" formatting option works like "%s" but with the
2185: ** addition that after the string has been read and copied into
2186: ** the result, [sqlite3_free()] is called on the input string.)^
2187: */
2188: SQLITE_API char *sqlite3_mprintf(const char*,...);
2189: SQLITE_API char *sqlite3_vmprintf(const char*, va_list);
2190: SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...);
2191: SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list);
2192:
2193: /*
2194: ** CAPI3REF: Memory Allocation Subsystem
2195: **
2196: ** The SQLite core uses these three routines for all of its own
2197: ** internal memory allocation needs. "Core" in the previous sentence
2198: ** does not include operating-system specific VFS implementation. The
2199: ** Windows VFS uses native malloc() and free() for some operations.
2200: **
2201: ** ^The sqlite3_malloc() routine returns a pointer to a block
2202: ** of memory at least N bytes in length, where N is the parameter.
2203: ** ^If sqlite3_malloc() is unable to obtain sufficient free
2204: ** memory, it returns a NULL pointer. ^If the parameter N to
2205: ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
2206: ** a NULL pointer.
2207: **
2208: ** ^Calling sqlite3_free() with a pointer previously returned
2209: ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
2210: ** that it might be reused. ^The sqlite3_free() routine is
2211: ** a no-op if is called with a NULL pointer. Passing a NULL pointer
2212: ** to sqlite3_free() is harmless. After being freed, memory
2213: ** should neither be read nor written. Even reading previously freed
2214: ** memory might result in a segmentation fault or other severe error.
2215: ** Memory corruption, a segmentation fault, or other severe error
2216: ** might result if sqlite3_free() is called with a non-NULL pointer that
2217: ** was not obtained from sqlite3_malloc() or sqlite3_realloc().
2218: **
2219: ** ^(The sqlite3_realloc() interface attempts to resize a
2220: ** prior memory allocation to be at least N bytes, where N is the
2221: ** second parameter. The memory allocation to be resized is the first
2222: ** parameter.)^ ^ If the first parameter to sqlite3_realloc()
2223: ** is a NULL pointer then its behavior is identical to calling
2224: ** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc().
2225: ** ^If the second parameter to sqlite3_realloc() is zero or
2226: ** negative then the behavior is exactly the same as calling
2227: ** sqlite3_free(P) where P is the first parameter to sqlite3_realloc().
2228: ** ^sqlite3_realloc() returns a pointer to a memory allocation
2229: ** of at least N bytes in size or NULL if sufficient memory is unavailable.
2230: ** ^If M is the size of the prior allocation, then min(N,M) bytes
2231: ** of the prior allocation are copied into the beginning of buffer returned
2232: ** by sqlite3_realloc() and the prior allocation is freed.
2233: ** ^If sqlite3_realloc() returns NULL, then the prior allocation
2234: ** is not freed.
2235: **
2236: ** ^The memory returned by sqlite3_malloc() and sqlite3_realloc()
2237: ** is always aligned to at least an 8 byte boundary, or to a
2238: ** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
2239: ** option is used.
2240: **
2241: ** In SQLite version 3.5.0 and 3.5.1, it was possible to define
2242: ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in
2243: ** implementation of these routines to be omitted. That capability
2244: ** is no longer provided. Only built-in memory allocators can be used.
2245: **
1.3 ! misho 2246: ** Prior to SQLite version 3.7.10, the Windows OS interface layer called
1.2 misho 2247: ** the system malloc() and free() directly when converting
2248: ** filenames between the UTF-8 encoding used by SQLite
2249: ** and whatever filename encoding is used by the particular Windows
1.3 ! misho 2250: ** installation. Memory allocation errors were detected, but
! 2251: ** they were reported back as [SQLITE_CANTOPEN] or
1.2 misho 2252: ** [SQLITE_IOERR] rather than [SQLITE_NOMEM].
2253: **
2254: ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
2255: ** must be either NULL or else pointers obtained from a prior
2256: ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
2257: ** not yet been released.
2258: **
2259: ** The application must not read or write any part of
2260: ** a block of memory after it has been released using
2261: ** [sqlite3_free()] or [sqlite3_realloc()].
2262: */
2263: SQLITE_API void *sqlite3_malloc(int);
2264: SQLITE_API void *sqlite3_realloc(void*, int);
2265: SQLITE_API void sqlite3_free(void*);
2266:
2267: /*
2268: ** CAPI3REF: Memory Allocator Statistics
2269: **
2270: ** SQLite provides these two interfaces for reporting on the status
2271: ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
2272: ** routines, which form the built-in memory allocation subsystem.
2273: **
2274: ** ^The [sqlite3_memory_used()] routine returns the number of bytes
2275: ** of memory currently outstanding (malloced but not freed).
2276: ** ^The [sqlite3_memory_highwater()] routine returns the maximum
2277: ** value of [sqlite3_memory_used()] since the high-water mark
2278: ** was last reset. ^The values returned by [sqlite3_memory_used()] and
2279: ** [sqlite3_memory_highwater()] include any overhead
2280: ** added by SQLite in its implementation of [sqlite3_malloc()],
2281: ** but not overhead added by the any underlying system library
2282: ** routines that [sqlite3_malloc()] may call.
2283: **
2284: ** ^The memory high-water mark is reset to the current value of
2285: ** [sqlite3_memory_used()] if and only if the parameter to
2286: ** [sqlite3_memory_highwater()] is true. ^The value returned
2287: ** by [sqlite3_memory_highwater(1)] is the high-water mark
2288: ** prior to the reset.
2289: */
2290: SQLITE_API sqlite3_int64 sqlite3_memory_used(void);
2291: SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
2292:
2293: /*
2294: ** CAPI3REF: Pseudo-Random Number Generator
2295: **
2296: ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
2297: ** select random [ROWID | ROWIDs] when inserting new records into a table that
2298: ** already uses the largest possible [ROWID]. The PRNG is also used for
2299: ** the build-in random() and randomblob() SQL functions. This interface allows
2300: ** applications to access the same PRNG for other purposes.
2301: **
2302: ** ^A call to this routine stores N bytes of randomness into buffer P.
2303: **
2304: ** ^The first time this routine is invoked (either internally or by
2305: ** the application) the PRNG is seeded using randomness obtained
2306: ** from the xRandomness method of the default [sqlite3_vfs] object.
2307: ** ^On all subsequent invocations, the pseudo-randomness is generated
2308: ** internally and without recourse to the [sqlite3_vfs] xRandomness
2309: ** method.
2310: */
2311: SQLITE_API void sqlite3_randomness(int N, void *P);
2312:
2313: /*
2314: ** CAPI3REF: Compile-Time Authorization Callbacks
2315: **
2316: ** ^This routine registers an authorizer callback with a particular
2317: ** [database connection], supplied in the first argument.
2318: ** ^The authorizer callback is invoked as SQL statements are being compiled
2319: ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
2320: ** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various
2321: ** points during the compilation process, as logic is being created
2322: ** to perform various actions, the authorizer callback is invoked to
2323: ** see if those actions are allowed. ^The authorizer callback should
2324: ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
2325: ** specific action but allow the SQL statement to continue to be
2326: ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
2327: ** rejected with an error. ^If the authorizer callback returns
2328: ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
2329: ** then the [sqlite3_prepare_v2()] or equivalent call that triggered
2330: ** the authorizer will fail with an error message.
2331: **
2332: ** When the callback returns [SQLITE_OK], that means the operation
2333: ** requested is ok. ^When the callback returns [SQLITE_DENY], the
2334: ** [sqlite3_prepare_v2()] or equivalent call that triggered the
2335: ** authorizer will fail with an error message explaining that
2336: ** access is denied.
2337: **
2338: ** ^The first parameter to the authorizer callback is a copy of the third
2339: ** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
2340: ** to the callback is an integer [SQLITE_COPY | action code] that specifies
2341: ** the particular action to be authorized. ^The third through sixth parameters
2342: ** to the callback are zero-terminated strings that contain additional
2343: ** details about the action to be authorized.
2344: **
2345: ** ^If the action code is [SQLITE_READ]
2346: ** and the callback returns [SQLITE_IGNORE] then the
2347: ** [prepared statement] statement is constructed to substitute
2348: ** a NULL value in place of the table column that would have
2349: ** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE]
2350: ** return can be used to deny an untrusted user access to individual
2351: ** columns of a table.
2352: ** ^If the action code is [SQLITE_DELETE] and the callback returns
2353: ** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
2354: ** [truncate optimization] is disabled and all rows are deleted individually.
2355: **
2356: ** An authorizer is used when [sqlite3_prepare | preparing]
2357: ** SQL statements from an untrusted source, to ensure that the SQL statements
2358: ** do not try to access data they are not allowed to see, or that they do not
2359: ** try to execute malicious statements that damage the database. For
2360: ** example, an application may allow a user to enter arbitrary
2361: ** SQL queries for evaluation by a database. But the application does
2362: ** not want the user to be able to make arbitrary changes to the
2363: ** database. An authorizer could then be put in place while the
2364: ** user-entered SQL is being [sqlite3_prepare | prepared] that
2365: ** disallows everything except [SELECT] statements.
2366: **
2367: ** Applications that need to process SQL from untrusted sources
2368: ** might also consider lowering resource limits using [sqlite3_limit()]
2369: ** and limiting database size using the [max_page_count] [PRAGMA]
2370: ** in addition to using an authorizer.
2371: **
2372: ** ^(Only a single authorizer can be in place on a database connection
2373: ** at a time. Each call to sqlite3_set_authorizer overrides the
2374: ** previous call.)^ ^Disable the authorizer by installing a NULL callback.
2375: ** The authorizer is disabled by default.
2376: **
2377: ** The authorizer callback must not do anything that will modify
2378: ** the database connection that invoked the authorizer callback.
2379: ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2380: ** database connections for the meaning of "modify" in this paragraph.
2381: **
2382: ** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
2383: ** statement might be re-prepared during [sqlite3_step()] due to a
2384: ** schema change. Hence, the application should ensure that the
2385: ** correct authorizer callback remains in place during the [sqlite3_step()].
2386: **
2387: ** ^Note that the authorizer callback is invoked only during
2388: ** [sqlite3_prepare()] or its variants. Authorization is not
2389: ** performed during statement evaluation in [sqlite3_step()], unless
2390: ** as stated in the previous paragraph, sqlite3_step() invokes
2391: ** sqlite3_prepare_v2() to reprepare a statement after a schema change.
2392: */
2393: SQLITE_API int sqlite3_set_authorizer(
2394: sqlite3*,
2395: int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
2396: void *pUserData
2397: );
2398:
2399: /*
2400: ** CAPI3REF: Authorizer Return Codes
2401: **
2402: ** The [sqlite3_set_authorizer | authorizer callback function] must
2403: ** return either [SQLITE_OK] or one of these two constants in order
2404: ** to signal SQLite whether or not the action is permitted. See the
2405: ** [sqlite3_set_authorizer | authorizer documentation] for additional
2406: ** information.
2407: **
2408: ** Note that SQLITE_IGNORE is also used as a [SQLITE_ROLLBACK | return code]
2409: ** from the [sqlite3_vtab_on_conflict()] interface.
2410: */
2411: #define SQLITE_DENY 1 /* Abort the SQL statement with an error */
2412: #define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */
2413:
2414: /*
2415: ** CAPI3REF: Authorizer Action Codes
2416: **
2417: ** The [sqlite3_set_authorizer()] interface registers a callback function
2418: ** that is invoked to authorize certain SQL statement actions. The
2419: ** second parameter to the callback is an integer code that specifies
2420: ** what action is being authorized. These are the integer action codes that
2421: ** the authorizer callback may be passed.
2422: **
2423: ** These action code values signify what kind of operation is to be
2424: ** authorized. The 3rd and 4th parameters to the authorization
2425: ** callback function will be parameters or NULL depending on which of these
2426: ** codes is used as the second parameter. ^(The 5th parameter to the
2427: ** authorizer callback is the name of the database ("main", "temp",
2428: ** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback
2429: ** is the name of the inner-most trigger or view that is responsible for
2430: ** the access attempt or NULL if this access attempt is directly from
2431: ** top-level SQL code.
2432: */
2433: /******************************************* 3rd ************ 4th ***********/
2434: #define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */
2435: #define SQLITE_CREATE_TABLE 2 /* Table Name NULL */
2436: #define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */
2437: #define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */
2438: #define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */
2439: #define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */
2440: #define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */
2441: #define SQLITE_CREATE_VIEW 8 /* View Name NULL */
2442: #define SQLITE_DELETE 9 /* Table Name NULL */
2443: #define SQLITE_DROP_INDEX 10 /* Index Name Table Name */
2444: #define SQLITE_DROP_TABLE 11 /* Table Name NULL */
2445: #define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */
2446: #define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */
2447: #define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */
2448: #define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */
2449: #define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */
2450: #define SQLITE_DROP_VIEW 17 /* View Name NULL */
2451: #define SQLITE_INSERT 18 /* Table Name NULL */
2452: #define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */
2453: #define SQLITE_READ 20 /* Table Name Column Name */
2454: #define SQLITE_SELECT 21 /* NULL NULL */
2455: #define SQLITE_TRANSACTION 22 /* Operation NULL */
2456: #define SQLITE_UPDATE 23 /* Table Name Column Name */
2457: #define SQLITE_ATTACH 24 /* Filename NULL */
2458: #define SQLITE_DETACH 25 /* Database Name NULL */
2459: #define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */
2460: #define SQLITE_REINDEX 27 /* Index Name NULL */
2461: #define SQLITE_ANALYZE 28 /* Table Name NULL */
2462: #define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */
2463: #define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */
2464: #define SQLITE_FUNCTION 31 /* NULL Function Name */
2465: #define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */
2466: #define SQLITE_COPY 0 /* No longer used */
2467:
2468: /*
2469: ** CAPI3REF: Tracing And Profiling Functions
2470: **
2471: ** These routines register callback functions that can be used for
2472: ** tracing and profiling the execution of SQL statements.
2473: **
2474: ** ^The callback function registered by sqlite3_trace() is invoked at
2475: ** various times when an SQL statement is being run by [sqlite3_step()].
2476: ** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
2477: ** SQL statement text as the statement first begins executing.
2478: ** ^(Additional sqlite3_trace() callbacks might occur
2479: ** as each triggered subprogram is entered. The callbacks for triggers
2480: ** contain a UTF-8 SQL comment that identifies the trigger.)^
2481: **
2482: ** ^The callback function registered by sqlite3_profile() is invoked
2483: ** as each SQL statement finishes. ^The profile callback contains
2484: ** the original statement text and an estimate of wall-clock time
2485: ** of how long that statement took to run. ^The profile callback
2486: ** time is in units of nanoseconds, however the current implementation
2487: ** is only capable of millisecond resolution so the six least significant
2488: ** digits in the time are meaningless. Future versions of SQLite
2489: ** might provide greater resolution on the profiler callback. The
2490: ** sqlite3_profile() function is considered experimental and is
2491: ** subject to change in future versions of SQLite.
2492: */
2493: SQLITE_API void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*);
2494: SQLITE_API SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*,
2495: void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
2496:
2497: /*
2498: ** CAPI3REF: Query Progress Callbacks
2499: **
2500: ** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
2501: ** function X to be invoked periodically during long running calls to
2502: ** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for
2503: ** database connection D. An example use for this
2504: ** interface is to keep a GUI updated during a large query.
2505: **
2506: ** ^The parameter P is passed through as the only parameter to the
2507: ** callback function X. ^The parameter N is the number of
2508: ** [virtual machine instructions] that are evaluated between successive
2509: ** invocations of the callback X.
2510: **
2511: ** ^Only a single progress handler may be defined at one time per
2512: ** [database connection]; setting a new progress handler cancels the
2513: ** old one. ^Setting parameter X to NULL disables the progress handler.
2514: ** ^The progress handler is also disabled by setting N to a value less
2515: ** than 1.
2516: **
2517: ** ^If the progress callback returns non-zero, the operation is
2518: ** interrupted. This feature can be used to implement a
2519: ** "Cancel" button on a GUI progress dialog box.
2520: **
2521: ** The progress handler callback must not do anything that will modify
2522: ** the database connection that invoked the progress handler.
2523: ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2524: ** database connections for the meaning of "modify" in this paragraph.
2525: **
2526: */
2527: SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
2528:
2529: /*
2530: ** CAPI3REF: Opening A New Database Connection
2531: **
2532: ** ^These routines open an SQLite database file as specified by the
2533: ** filename argument. ^The filename argument is interpreted as UTF-8 for
2534: ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
2535: ** order for sqlite3_open16(). ^(A [database connection] handle is usually
2536: ** returned in *ppDb, even if an error occurs. The only exception is that
2537: ** if SQLite is unable to allocate memory to hold the [sqlite3] object,
2538: ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
2539: ** object.)^ ^(If the database is opened (and/or created) successfully, then
2540: ** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The
2541: ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
2542: ** an English language description of the error following a failure of any
2543: ** of the sqlite3_open() routines.
2544: **
2545: ** ^The default encoding for the database will be UTF-8 if
2546: ** sqlite3_open() or sqlite3_open_v2() is called and
2547: ** UTF-16 in the native byte order if sqlite3_open16() is used.
2548: **
2549: ** Whether or not an error occurs when it is opened, resources
2550: ** associated with the [database connection] handle should be released by
2551: ** passing it to [sqlite3_close()] when it is no longer required.
2552: **
2553: ** The sqlite3_open_v2() interface works like sqlite3_open()
2554: ** except that it accepts two additional parameters for additional control
2555: ** over the new database connection. ^(The flags parameter to
2556: ** sqlite3_open_v2() can take one of
2557: ** the following three values, optionally combined with the
2558: ** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE],
2559: ** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^
2560: **
2561: ** <dl>
2562: ** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
2563: ** <dd>The database is opened in read-only mode. If the database does not
2564: ** already exist, an error is returned.</dd>)^
2565: **
2566: ** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
2567: ** <dd>The database is opened for reading and writing if possible, or reading
2568: ** only if the file is write protected by the operating system. In either
2569: ** case the database must already exist, otherwise an error is returned.</dd>)^
2570: **
2571: ** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
2572: ** <dd>The database is opened for reading and writing, and is created if
2573: ** it does not already exist. This is the behavior that is always used for
2574: ** sqlite3_open() and sqlite3_open16().</dd>)^
2575: ** </dl>
2576: **
2577: ** If the 3rd parameter to sqlite3_open_v2() is not one of the
2578: ** combinations shown above optionally combined with other
2579: ** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits]
2580: ** then the behavior is undefined.
2581: **
2582: ** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection
2583: ** opens in the multi-thread [threading mode] as long as the single-thread
2584: ** mode has not been set at compile-time or start-time. ^If the
2585: ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens
2586: ** in the serialized [threading mode] unless single-thread was
2587: ** previously selected at compile-time or start-time.
2588: ** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be
2589: ** eligible to use [shared cache mode], regardless of whether or not shared
2590: ** cache is enabled using [sqlite3_enable_shared_cache()]. ^The
2591: ** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not
2592: ** participate in [shared cache mode] even if it is enabled.
2593: **
2594: ** ^The fourth parameter to sqlite3_open_v2() is the name of the
2595: ** [sqlite3_vfs] object that defines the operating system interface that
2596: ** the new database connection should use. ^If the fourth parameter is
2597: ** a NULL pointer then the default [sqlite3_vfs] object is used.
2598: **
2599: ** ^If the filename is ":memory:", then a private, temporary in-memory database
2600: ** is created for the connection. ^This in-memory database will vanish when
2601: ** the database connection is closed. Future versions of SQLite might
2602: ** make use of additional special filenames that begin with the ":" character.
2603: ** It is recommended that when a database filename actually does begin with
2604: ** a ":" character you should prefix the filename with a pathname such as
2605: ** "./" to avoid ambiguity.
2606: **
2607: ** ^If the filename is an empty string, then a private, temporary
2608: ** on-disk database will be created. ^This private database will be
2609: ** automatically deleted as soon as the database connection is closed.
2610: **
2611: ** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
2612: **
2613: ** ^If [URI filename] interpretation is enabled, and the filename argument
2614: ** begins with "file:", then the filename is interpreted as a URI. ^URI
2615: ** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
2616: ** set in the fourth argument to sqlite3_open_v2(), or if it has
2617: ** been enabled globally using the [SQLITE_CONFIG_URI] option with the
2618: ** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
2619: ** As of SQLite version 3.7.7, URI filename interpretation is turned off
2620: ** by default, but future releases of SQLite might enable URI filename
2621: ** interpretation by default. See "[URI filenames]" for additional
2622: ** information.
2623: **
2624: ** URI filenames are parsed according to RFC 3986. ^If the URI contains an
2625: ** authority, then it must be either an empty string or the string
2626: ** "localhost". ^If the authority is not an empty string or "localhost", an
2627: ** error is returned to the caller. ^The fragment component of a URI, if
2628: ** present, is ignored.
2629: **
2630: ** ^SQLite uses the path component of the URI as the name of the disk file
2631: ** which contains the database. ^If the path begins with a '/' character,
2632: ** then it is interpreted as an absolute path. ^If the path does not begin
2633: ** with a '/' (meaning that the authority section is omitted from the URI)
2634: ** then the path is interpreted as a relative path.
2635: ** ^On windows, the first component of an absolute path
2636: ** is a drive specification (e.g. "C:").
2637: **
2638: ** [[core URI query parameters]]
2639: ** The query component of a URI may contain parameters that are interpreted
2640: ** either by SQLite itself, or by a [VFS | custom VFS implementation].
2641: ** SQLite interprets the following three query parameters:
2642: **
2643: ** <ul>
2644: ** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
2645: ** a VFS object that provides the operating system interface that should
2646: ** be used to access the database file on disk. ^If this option is set to
2647: ** an empty string the default VFS object is used. ^Specifying an unknown
2648: ** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
2649: ** present, then the VFS specified by the option takes precedence over
2650: ** the value passed as the fourth parameter to sqlite3_open_v2().
2651: **
1.3 ! misho 2652: ** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw",
! 2653: ** "rwc", or "memory". Attempting to set it to any other value is
! 2654: ** an error)^.
1.2 misho 2655: ** ^If "ro" is specified, then the database is opened for read-only
2656: ** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the
1.3 ! misho 2657: ** third argument to sqlite3_open_v2(). ^If the mode option is set to
1.2 misho 2658: ** "rw", then the database is opened for read-write (but not create)
2659: ** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had
2660: ** been set. ^Value "rwc" is equivalent to setting both
1.3 ! misho 2661: ** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is
! 2662: ** set to "memory" then a pure [in-memory database] that never reads
! 2663: ** or writes from disk is used. ^It is an error to specify a value for
! 2664: ** the mode parameter that is less restrictive than that specified by
! 2665: ** the flags passed in the third parameter to sqlite3_open_v2().
1.2 misho 2666: **
2667: ** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
2668: ** "private". ^Setting it to "shared" is equivalent to setting the
2669: ** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
2670: ** sqlite3_open_v2(). ^Setting the cache parameter to "private" is
2671: ** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
2672: ** ^If sqlite3_open_v2() is used and the "cache" parameter is present in
2673: ** a URI filename, its value overrides any behaviour requested by setting
2674: ** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.
2675: ** </ul>
2676: **
2677: ** ^Specifying an unknown parameter in the query component of a URI is not an
2678: ** error. Future versions of SQLite might understand additional query
2679: ** parameters. See "[query parameters with special meaning to SQLite]" for
2680: ** additional information.
2681: **
2682: ** [[URI filename examples]] <h3>URI filename examples</h3>
2683: **
2684: ** <table border="1" align=center cellpadding=5>
2685: ** <tr><th> URI filenames <th> Results
2686: ** <tr><td> file:data.db <td>
2687: ** Open the file "data.db" in the current directory.
2688: ** <tr><td> file:/home/fred/data.db<br>
2689: ** file:///home/fred/data.db <br>
2690: ** file://localhost/home/fred/data.db <br> <td>
2691: ** Open the database file "/home/fred/data.db".
2692: ** <tr><td> file://darkstar/home/fred/data.db <td>
2693: ** An error. "darkstar" is not a recognized authority.
2694: ** <tr><td style="white-space:nowrap">
2695: ** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
2696: ** <td> Windows only: Open the file "data.db" on fred's desktop on drive
2697: ** C:. Note that the %20 escaping in this example is not strictly
2698: ** necessary - space characters can be used literally
2699: ** in URI filenames.
2700: ** <tr><td> file:data.db?mode=ro&cache=private <td>
2701: ** Open file "data.db" in the current directory for read-only access.
2702: ** Regardless of whether or not shared-cache mode is enabled by
2703: ** default, use a private cache.
2704: ** <tr><td> file:/home/fred/data.db?vfs=unix-nolock <td>
2705: ** Open file "/home/fred/data.db". Use the special VFS "unix-nolock".
2706: ** <tr><td> file:data.db?mode=readonly <td>
2707: ** An error. "readonly" is not a valid option for the "mode" parameter.
2708: ** </table>
2709: **
2710: ** ^URI hexadecimal escape sequences (%HH) are supported within the path and
2711: ** query components of a URI. A hexadecimal escape sequence consists of a
2712: ** percent sign - "%" - followed by exactly two hexadecimal digits
2713: ** specifying an octet value. ^Before the path or query components of a
2714: ** URI filename are interpreted, they are encoded using UTF-8 and all
2715: ** hexadecimal escape sequences replaced by a single byte containing the
2716: ** corresponding octet. If this process generates an invalid UTF-8 encoding,
2717: ** the results are undefined.
2718: **
2719: ** <b>Note to Windows users:</b> The encoding used for the filename argument
2720: ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
2721: ** codepage is currently defined. Filenames containing international
2722: ** characters must be converted to UTF-8 prior to passing them into
2723: ** sqlite3_open() or sqlite3_open_v2().
1.3 ! misho 2724: **
! 2725: ** <b>Note to Windows Runtime users:</b> The temporary directory must be set
! 2726: ** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various
! 2727: ** features that require the use of temporary files may fail.
! 2728: **
! 2729: ** See also: [sqlite3_temp_directory]
1.2 misho 2730: */
2731: SQLITE_API int sqlite3_open(
2732: const char *filename, /* Database filename (UTF-8) */
2733: sqlite3 **ppDb /* OUT: SQLite db handle */
2734: );
2735: SQLITE_API int sqlite3_open16(
2736: const void *filename, /* Database filename (UTF-16) */
2737: sqlite3 **ppDb /* OUT: SQLite db handle */
2738: );
2739: SQLITE_API int sqlite3_open_v2(
2740: const char *filename, /* Database filename (UTF-8) */
2741: sqlite3 **ppDb, /* OUT: SQLite db handle */
2742: int flags, /* Flags */
2743: const char *zVfs /* Name of VFS module to use */
2744: );
2745:
2746: /*
2747: ** CAPI3REF: Obtain Values For URI Parameters
2748: **
2749: ** These are utility routines, useful to VFS implementations, that check
2750: ** to see if a database file was a URI that contained a specific query
2751: ** parameter, and if so obtains the value of that query parameter.
2752: **
2753: ** If F is the database filename pointer passed into the xOpen() method of
2754: ** a VFS implementation when the flags parameter to xOpen() has one or
2755: ** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and
2756: ** P is the name of the query parameter, then
2757: ** sqlite3_uri_parameter(F,P) returns the value of the P
2758: ** parameter if it exists or a NULL pointer if P does not appear as a
2759: ** query parameter on F. If P is a query parameter of F
2760: ** has no explicit value, then sqlite3_uri_parameter(F,P) returns
2761: ** a pointer to an empty string.
2762: **
2763: ** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
2764: ** parameter and returns true (1) or false (0) according to the value
1.3 ! misho 2765: ** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
! 2766: ** value of query parameter P is one of "yes", "true", or "on" in any
! 2767: ** case or if the value begins with a non-zero number. The
! 2768: ** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
! 2769: ** query parameter P is one of "no", "false", or "off" in any case or
! 2770: ** if the value begins with a numeric zero. If P is not a query
! 2771: ** parameter on F or if the value of P is does not match any of the
! 2772: ** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).
1.2 misho 2773: **
2774: ** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
2775: ** 64-bit signed integer and returns that integer, or D if P does not
2776: ** exist. If the value of P is something other than an integer, then
2777: ** zero is returned.
2778: **
2779: ** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
2780: ** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and
2781: ** is not a database file pathname pointer that SQLite passed into the xOpen
2782: ** VFS method, then the behavior of this routine is undefined and probably
2783: ** undesirable.
2784: */
2785: SQLITE_API const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam);
2786: SQLITE_API int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault);
2787: SQLITE_API sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64);
2788:
2789:
2790: /*
2791: ** CAPI3REF: Error Codes And Messages
2792: **
2793: ** ^The sqlite3_errcode() interface returns the numeric [result code] or
2794: ** [extended result code] for the most recent failed sqlite3_* API call
2795: ** associated with a [database connection]. If a prior API call failed
2796: ** but the most recent API call succeeded, the return value from
2797: ** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode()
2798: ** interface is the same except that it always returns the
2799: ** [extended result code] even when extended result codes are
2800: ** disabled.
2801: **
2802: ** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
2803: ** text that describes the error, as either UTF-8 or UTF-16 respectively.
2804: ** ^(Memory to hold the error message string is managed internally.
2805: ** The application does not need to worry about freeing the result.
2806: ** However, the error string might be overwritten or deallocated by
2807: ** subsequent calls to other SQLite interface functions.)^
2808: **
1.3 ! misho 2809: ** ^The sqlite3_errstr() interface returns the English-language text
! 2810: ** that describes the [result code], as UTF-8.
! 2811: ** ^(Memory to hold the error message string is managed internally
! 2812: ** and must not be freed by the application)^.
! 2813: **
1.2 misho 2814: ** When the serialized [threading mode] is in use, it might be the
2815: ** case that a second error occurs on a separate thread in between
2816: ** the time of the first error and the call to these interfaces.
2817: ** When that happens, the second error will be reported since these
2818: ** interfaces always report the most recent result. To avoid
2819: ** this, each thread can obtain exclusive use of the [database connection] D
2820: ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
2821: ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
2822: ** all calls to the interfaces listed here are completed.
2823: **
2824: ** If an interface fails with SQLITE_MISUSE, that means the interface
2825: ** was invoked incorrectly by the application. In that case, the
2826: ** error code and message may or may not be set.
2827: */
2828: SQLITE_API int sqlite3_errcode(sqlite3 *db);
2829: SQLITE_API int sqlite3_extended_errcode(sqlite3 *db);
2830: SQLITE_API const char *sqlite3_errmsg(sqlite3*);
2831: SQLITE_API const void *sqlite3_errmsg16(sqlite3*);
1.3 ! misho 2832: SQLITE_API const char *sqlite3_errstr(int);
1.2 misho 2833:
2834: /*
2835: ** CAPI3REF: SQL Statement Object
2836: ** KEYWORDS: {prepared statement} {prepared statements}
2837: **
2838: ** An instance of this object represents a single SQL statement.
2839: ** This object is variously known as a "prepared statement" or a
2840: ** "compiled SQL statement" or simply as a "statement".
2841: **
2842: ** The life of a statement object goes something like this:
2843: **
2844: ** <ol>
2845: ** <li> Create the object using [sqlite3_prepare_v2()] or a related
2846: ** function.
2847: ** <li> Bind values to [host parameters] using the sqlite3_bind_*()
2848: ** interfaces.
2849: ** <li> Run the SQL by calling [sqlite3_step()] one or more times.
2850: ** <li> Reset the statement using [sqlite3_reset()] then go back
2851: ** to step 2. Do this zero or more times.
2852: ** <li> Destroy the object using [sqlite3_finalize()].
2853: ** </ol>
2854: **
2855: ** Refer to documentation on individual methods above for additional
2856: ** information.
2857: */
2858: typedef struct sqlite3_stmt sqlite3_stmt;
2859:
2860: /*
2861: ** CAPI3REF: Run-time Limits
2862: **
2863: ** ^(This interface allows the size of various constructs to be limited
2864: ** on a connection by connection basis. The first parameter is the
2865: ** [database connection] whose limit is to be set or queried. The
2866: ** second parameter is one of the [limit categories] that define a
2867: ** class of constructs to be size limited. The third parameter is the
2868: ** new limit for that construct.)^
2869: **
2870: ** ^If the new limit is a negative number, the limit is unchanged.
2871: ** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
2872: ** [limits | hard upper bound]
2873: ** set at compile-time by a C preprocessor macro called
2874: ** [limits | SQLITE_MAX_<i>NAME</i>].
2875: ** (The "_LIMIT_" in the name is changed to "_MAX_".))^
2876: ** ^Attempts to increase a limit above its hard upper bound are
2877: ** silently truncated to the hard upper bound.
2878: **
2879: ** ^Regardless of whether or not the limit was changed, the
2880: ** [sqlite3_limit()] interface returns the prior value of the limit.
2881: ** ^Hence, to find the current value of a limit without changing it,
2882: ** simply invoke this interface with the third parameter set to -1.
2883: **
2884: ** Run-time limits are intended for use in applications that manage
2885: ** both their own internal database and also databases that are controlled
2886: ** by untrusted external sources. An example application might be a
2887: ** web browser that has its own databases for storing history and
2888: ** separate databases controlled by JavaScript applications downloaded
2889: ** off the Internet. The internal databases can be given the
2890: ** large, default limits. Databases managed by external sources can
2891: ** be given much smaller limits designed to prevent a denial of service
2892: ** attack. Developers might also want to use the [sqlite3_set_authorizer()]
2893: ** interface to further control untrusted SQL. The size of the database
2894: ** created by an untrusted script can be contained using the
2895: ** [max_page_count] [PRAGMA].
2896: **
2897: ** New run-time limit categories may be added in future releases.
2898: */
2899: SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal);
2900:
2901: /*
2902: ** CAPI3REF: Run-Time Limit Categories
2903: ** KEYWORDS: {limit category} {*limit categories}
2904: **
2905: ** These constants define various performance limits
2906: ** that can be lowered at run-time using [sqlite3_limit()].
2907: ** The synopsis of the meanings of the various limits is shown below.
2908: ** Additional information is available at [limits | Limits in SQLite].
2909: **
2910: ** <dl>
2911: ** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt>
2912: ** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
2913: **
2914: ** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
2915: ** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
2916: **
2917: ** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt>
2918: ** <dd>The maximum number of columns in a table definition or in the
2919: ** result set of a [SELECT] or the maximum number of columns in an index
2920: ** or in an ORDER BY or GROUP BY clause.</dd>)^
2921: **
2922: ** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
2923: ** <dd>The maximum depth of the parse tree on any expression.</dd>)^
2924: **
2925: ** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
2926: ** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
2927: **
2928: ** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
2929: ** <dd>The maximum number of instructions in a virtual machine program
2930: ** used to implement an SQL statement. This limit is not currently
2931: ** enforced, though that might be added in some future release of
2932: ** SQLite.</dd>)^
2933: **
2934: ** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
2935: ** <dd>The maximum number of arguments on a function.</dd>)^
2936: **
2937: ** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
2938: ** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
2939: **
2940: ** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]]
2941: ** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
2942: ** <dd>The maximum length of the pattern argument to the [LIKE] or
2943: ** [GLOB] operators.</dd>)^
2944: **
2945: ** [[SQLITE_LIMIT_VARIABLE_NUMBER]]
2946: ** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
2947: ** <dd>The maximum index number of any [parameter] in an SQL statement.)^
2948: **
2949: ** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
2950: ** <dd>The maximum depth of recursion for triggers.</dd>)^
2951: ** </dl>
2952: */
2953: #define SQLITE_LIMIT_LENGTH 0
2954: #define SQLITE_LIMIT_SQL_LENGTH 1
2955: #define SQLITE_LIMIT_COLUMN 2
2956: #define SQLITE_LIMIT_EXPR_DEPTH 3
2957: #define SQLITE_LIMIT_COMPOUND_SELECT 4
2958: #define SQLITE_LIMIT_VDBE_OP 5
2959: #define SQLITE_LIMIT_FUNCTION_ARG 6
2960: #define SQLITE_LIMIT_ATTACHED 7
2961: #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8
2962: #define SQLITE_LIMIT_VARIABLE_NUMBER 9
2963: #define SQLITE_LIMIT_TRIGGER_DEPTH 10
2964:
2965: /*
2966: ** CAPI3REF: Compiling An SQL Statement
2967: ** KEYWORDS: {SQL statement compiler}
2968: **
2969: ** To execute an SQL query, it must first be compiled into a byte-code
2970: ** program using one of these routines.
2971: **
2972: ** The first argument, "db", is a [database connection] obtained from a
2973: ** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
2974: ** [sqlite3_open16()]. The database connection must not have been closed.
2975: **
2976: ** The second argument, "zSql", is the statement to be compiled, encoded
2977: ** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2()
2978: ** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2()
2979: ** use UTF-16.
2980: **
2981: ** ^If the nByte argument is less than zero, then zSql is read up to the
2982: ** first zero terminator. ^If nByte is non-negative, then it is the maximum
2983: ** number of bytes read from zSql. ^When nByte is non-negative, the
2984: ** zSql string ends at either the first '\000' or '\u0000' character or
2985: ** the nByte-th byte, whichever comes first. If the caller knows
2986: ** that the supplied string is nul-terminated, then there is a small
2987: ** performance advantage to be gained by passing an nByte parameter that
2988: ** is equal to the number of bytes in the input string <i>including</i>
2989: ** the nul-terminator bytes as this saves SQLite from having to
2990: ** make a copy of the input string.
2991: **
2992: ** ^If pzTail is not NULL then *pzTail is made to point to the first byte
2993: ** past the end of the first SQL statement in zSql. These routines only
2994: ** compile the first statement in zSql, so *pzTail is left pointing to
2995: ** what remains uncompiled.
2996: **
2997: ** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
2998: ** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set
2999: ** to NULL. ^If the input text contains no SQL (if the input is an empty
3000: ** string or a comment) then *ppStmt is set to NULL.
3001: ** The calling procedure is responsible for deleting the compiled
3002: ** SQL statement using [sqlite3_finalize()] after it has finished with it.
3003: ** ppStmt may not be NULL.
3004: **
3005: ** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
3006: ** otherwise an [error code] is returned.
3007: **
3008: ** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are
3009: ** recommended for all new programs. The two older interfaces are retained
3010: ** for backwards compatibility, but their use is discouraged.
3011: ** ^In the "v2" interfaces, the prepared statement
3012: ** that is returned (the [sqlite3_stmt] object) contains a copy of the
3013: ** original SQL text. This causes the [sqlite3_step()] interface to
3014: ** behave differently in three ways:
3015: **
3016: ** <ol>
3017: ** <li>
3018: ** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
3019: ** always used to do, [sqlite3_step()] will automatically recompile the SQL
3020: ** statement and try to run it again.
3021: ** </li>
3022: **
3023: ** <li>
3024: ** ^When an error occurs, [sqlite3_step()] will return one of the detailed
3025: ** [error codes] or [extended error codes]. ^The legacy behavior was that
3026: ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
3027: ** and the application would have to make a second call to [sqlite3_reset()]
3028: ** in order to find the underlying cause of the problem. With the "v2" prepare
3029: ** interfaces, the underlying reason for the error is returned immediately.
3030: ** </li>
3031: **
3032: ** <li>
3033: ** ^If the specific value bound to [parameter | host parameter] in the
3034: ** WHERE clause might influence the choice of query plan for a statement,
3035: ** then the statement will be automatically recompiled, as if there had been
3036: ** a schema change, on the first [sqlite3_step()] call following any change
3037: ** to the [sqlite3_bind_text | bindings] of that [parameter].
3038: ** ^The specific value of WHERE-clause [parameter] might influence the
3039: ** choice of query plan if the parameter is the left-hand side of a [LIKE]
3040: ** or [GLOB] operator or if the parameter is compared to an indexed column
3041: ** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled.
3042: ** the
3043: ** </li>
3044: ** </ol>
3045: */
3046: SQLITE_API int sqlite3_prepare(
3047: sqlite3 *db, /* Database handle */
3048: const char *zSql, /* SQL statement, UTF-8 encoded */
3049: int nByte, /* Maximum length of zSql in bytes. */
3050: sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3051: const char **pzTail /* OUT: Pointer to unused portion of zSql */
3052: );
3053: SQLITE_API int sqlite3_prepare_v2(
3054: sqlite3 *db, /* Database handle */
3055: const char *zSql, /* SQL statement, UTF-8 encoded */
3056: int nByte, /* Maximum length of zSql in bytes. */
3057: sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3058: const char **pzTail /* OUT: Pointer to unused portion of zSql */
3059: );
3060: SQLITE_API int sqlite3_prepare16(
3061: sqlite3 *db, /* Database handle */
3062: const void *zSql, /* SQL statement, UTF-16 encoded */
3063: int nByte, /* Maximum length of zSql in bytes. */
3064: sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3065: const void **pzTail /* OUT: Pointer to unused portion of zSql */
3066: );
3067: SQLITE_API int sqlite3_prepare16_v2(
3068: sqlite3 *db, /* Database handle */
3069: const void *zSql, /* SQL statement, UTF-16 encoded */
3070: int nByte, /* Maximum length of zSql in bytes. */
3071: sqlite3_stmt **ppStmt, /* OUT: Statement handle */
3072: const void **pzTail /* OUT: Pointer to unused portion of zSql */
3073: );
3074:
3075: /*
3076: ** CAPI3REF: Retrieving Statement SQL
3077: **
3078: ** ^This interface can be used to retrieve a saved copy of the original
3079: ** SQL text used to create a [prepared statement] if that statement was
3080: ** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()].
3081: */
3082: SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt);
3083:
3084: /*
3085: ** CAPI3REF: Determine If An SQL Statement Writes The Database
3086: **
3087: ** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
3088: ** and only if the [prepared statement] X makes no direct changes to
3089: ** the content of the database file.
3090: **
3091: ** Note that [application-defined SQL functions] or
3092: ** [virtual tables] might change the database indirectly as a side effect.
3093: ** ^(For example, if an application defines a function "eval()" that
3094: ** calls [sqlite3_exec()], then the following SQL statement would
3095: ** change the database file through side-effects:
3096: **
3097: ** <blockquote><pre>
3098: ** SELECT eval('DELETE FROM t1') FROM t2;
3099: ** </pre></blockquote>
3100: **
3101: ** But because the [SELECT] statement does not change the database file
3102: ** directly, sqlite3_stmt_readonly() would still return true.)^
3103: **
3104: ** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
3105: ** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
3106: ** since the statements themselves do not actually modify the database but
3107: ** rather they control the timing of when other statements modify the
3108: ** database. ^The [ATTACH] and [DETACH] statements also cause
3109: ** sqlite3_stmt_readonly() to return true since, while those statements
3110: ** change the configuration of a database connection, they do not make
3111: ** changes to the content of the database files on disk.
3112: */
3113: SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
3114:
3115: /*
3116: ** CAPI3REF: Determine If A Prepared Statement Has Been Reset
3117: **
3118: ** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
3119: ** [prepared statement] S has been stepped at least once using
3120: ** [sqlite3_step(S)] but has not run to completion and/or has not
3121: ** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S)
3122: ** interface returns false if S is a NULL pointer. If S is not a
3123: ** NULL pointer and is not a pointer to a valid [prepared statement]
3124: ** object, then the behavior is undefined and probably undesirable.
3125: **
3126: ** This interface can be used in combination [sqlite3_next_stmt()]
3127: ** to locate all prepared statements associated with a database
3128: ** connection that are in need of being reset. This can be used,
3129: ** for example, in diagnostic routines to search for prepared
3130: ** statements that are holding a transaction open.
3131: */
3132: SQLITE_API int sqlite3_stmt_busy(sqlite3_stmt*);
3133:
3134: /*
3135: ** CAPI3REF: Dynamically Typed Value Object
3136: ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
3137: **
3138: ** SQLite uses the sqlite3_value object to represent all values
3139: ** that can be stored in a database table. SQLite uses dynamic typing
3140: ** for the values it stores. ^Values stored in sqlite3_value objects
3141: ** can be integers, floating point values, strings, BLOBs, or NULL.
3142: **
3143: ** An sqlite3_value object may be either "protected" or "unprotected".
3144: ** Some interfaces require a protected sqlite3_value. Other interfaces
3145: ** will accept either a protected or an unprotected sqlite3_value.
3146: ** Every interface that accepts sqlite3_value arguments specifies
3147: ** whether or not it requires a protected sqlite3_value.
3148: **
3149: ** The terms "protected" and "unprotected" refer to whether or not
3150: ** a mutex is held. An internal mutex is held for a protected
3151: ** sqlite3_value object but no mutex is held for an unprotected
3152: ** sqlite3_value object. If SQLite is compiled to be single-threaded
3153: ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
3154: ** or if SQLite is run in one of reduced mutex modes
3155: ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
3156: ** then there is no distinction between protected and unprotected
3157: ** sqlite3_value objects and they can be used interchangeably. However,
3158: ** for maximum code portability it is recommended that applications
3159: ** still make the distinction between protected and unprotected
3160: ** sqlite3_value objects even when not strictly required.
3161: **
3162: ** ^The sqlite3_value objects that are passed as parameters into the
3163: ** implementation of [application-defined SQL functions] are protected.
3164: ** ^The sqlite3_value object returned by
3165: ** [sqlite3_column_value()] is unprotected.
3166: ** Unprotected sqlite3_value objects may only be used with
3167: ** [sqlite3_result_value()] and [sqlite3_bind_value()].
3168: ** The [sqlite3_value_blob | sqlite3_value_type()] family of
3169: ** interfaces require protected sqlite3_value objects.
3170: */
3171: typedef struct Mem sqlite3_value;
3172:
3173: /*
3174: ** CAPI3REF: SQL Function Context Object
3175: **
3176: ** The context in which an SQL function executes is stored in an
3177: ** sqlite3_context object. ^A pointer to an sqlite3_context object
3178: ** is always first parameter to [application-defined SQL functions].
3179: ** The application-defined SQL function implementation will pass this
3180: ** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
3181: ** [sqlite3_aggregate_context()], [sqlite3_user_data()],
3182: ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
3183: ** and/or [sqlite3_set_auxdata()].
3184: */
3185: typedef struct sqlite3_context sqlite3_context;
3186:
3187: /*
3188: ** CAPI3REF: Binding Values To Prepared Statements
3189: ** KEYWORDS: {host parameter} {host parameters} {host parameter name}
3190: ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
3191: **
3192: ** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
3193: ** literals may be replaced by a [parameter] that matches one of following
3194: ** templates:
3195: **
3196: ** <ul>
3197: ** <li> ?
3198: ** <li> ?NNN
3199: ** <li> :VVV
3200: ** <li> @VVV
3201: ** <li> $VVV
3202: ** </ul>
3203: **
3204: ** In the templates above, NNN represents an integer literal,
3205: ** and VVV represents an alphanumeric identifier.)^ ^The values of these
3206: ** parameters (also called "host parameter names" or "SQL parameters")
3207: ** can be set using the sqlite3_bind_*() routines defined here.
3208: **
3209: ** ^The first argument to the sqlite3_bind_*() routines is always
3210: ** a pointer to the [sqlite3_stmt] object returned from
3211: ** [sqlite3_prepare_v2()] or its variants.
3212: **
3213: ** ^The second argument is the index of the SQL parameter to be set.
3214: ** ^The leftmost SQL parameter has an index of 1. ^When the same named
3215: ** SQL parameter is used more than once, second and subsequent
3216: ** occurrences have the same index as the first occurrence.
3217: ** ^The index for named parameters can be looked up using the
3218: ** [sqlite3_bind_parameter_index()] API if desired. ^The index
3219: ** for "?NNN" parameters is the value of NNN.
3220: ** ^The NNN value must be between 1 and the [sqlite3_limit()]
3221: ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999).
3222: **
3223: ** ^The third argument is the value to bind to the parameter.
3224: **
3225: ** ^(In those routines that have a fourth argument, its value is the
3226: ** number of bytes in the parameter. To be clear: the value is the
3227: ** number of <u>bytes</u> in the value, not the number of characters.)^
1.3 ! misho 3228: ** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()
! 3229: ** is negative, then the length of the string is
1.2 misho 3230: ** the number of bytes up to the first zero terminator.
1.3 ! misho 3231: ** If the fourth parameter to sqlite3_bind_blob() is negative, then
! 3232: ** the behavior is undefined.
1.2 misho 3233: ** If a non-negative fourth parameter is provided to sqlite3_bind_text()
3234: ** or sqlite3_bind_text16() then that parameter must be the byte offset
3235: ** where the NUL terminator would occur assuming the string were NUL
3236: ** terminated. If any NUL characters occur at byte offsets less than
3237: ** the value of the fourth parameter then the resulting string value will
3238: ** contain embedded NULs. The result of expressions involving strings
3239: ** with embedded NULs is undefined.
3240: **
3241: ** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and
3242: ** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or
3243: ** string after SQLite has finished with it. ^The destructor is called
3244: ** to dispose of the BLOB or string even if the call to sqlite3_bind_blob(),
3245: ** sqlite3_bind_text(), or sqlite3_bind_text16() fails.
3246: ** ^If the fifth argument is
3247: ** the special value [SQLITE_STATIC], then SQLite assumes that the
3248: ** information is in static, unmanaged space and does not need to be freed.
3249: ** ^If the fifth argument has the value [SQLITE_TRANSIENT], then
3250: ** SQLite makes its own private copy of the data immediately, before
3251: ** the sqlite3_bind_*() routine returns.
3252: **
3253: ** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
3254: ** is filled with zeroes. ^A zeroblob uses a fixed amount of memory
3255: ** (just an integer to hold its size) while it is being processed.
3256: ** Zeroblobs are intended to serve as placeholders for BLOBs whose
3257: ** content is later written using
3258: ** [sqlite3_blob_open | incremental BLOB I/O] routines.
3259: ** ^A negative value for the zeroblob results in a zero-length BLOB.
3260: **
3261: ** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
3262: ** for the [prepared statement] or with a prepared statement for which
3263: ** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
3264: ** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_()
3265: ** routine is passed a [prepared statement] that has been finalized, the
3266: ** result is undefined and probably harmful.
3267: **
3268: ** ^Bindings are not cleared by the [sqlite3_reset()] routine.
3269: ** ^Unbound parameters are interpreted as NULL.
3270: **
3271: ** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
3272: ** [error code] if anything goes wrong.
3273: ** ^[SQLITE_RANGE] is returned if the parameter
3274: ** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails.
3275: **
3276: ** See also: [sqlite3_bind_parameter_count()],
3277: ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
3278: */
3279: SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
3280: SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double);
3281: SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int);
3282: SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
3283: SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int);
3284: SQLITE_API int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*));
3285: SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
3286: SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
3287: SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
3288:
3289: /*
3290: ** CAPI3REF: Number Of SQL Parameters
3291: **
3292: ** ^This routine can be used to find the number of [SQL parameters]
3293: ** in a [prepared statement]. SQL parameters are tokens of the
3294: ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
3295: ** placeholders for values that are [sqlite3_bind_blob | bound]
3296: ** to the parameters at a later time.
3297: **
3298: ** ^(This routine actually returns the index of the largest (rightmost)
3299: ** parameter. For all forms except ?NNN, this will correspond to the
3300: ** number of unique parameters. If parameters of the ?NNN form are used,
3301: ** there may be gaps in the list.)^
3302: **
3303: ** See also: [sqlite3_bind_blob|sqlite3_bind()],
3304: ** [sqlite3_bind_parameter_name()], and
3305: ** [sqlite3_bind_parameter_index()].
3306: */
3307: SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*);
3308:
3309: /*
3310: ** CAPI3REF: Name Of A Host Parameter
3311: **
3312: ** ^The sqlite3_bind_parameter_name(P,N) interface returns
3313: ** the name of the N-th [SQL parameter] in the [prepared statement] P.
3314: ** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
3315: ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
3316: ** respectively.
3317: ** In other words, the initial ":" or "$" or "@" or "?"
3318: ** is included as part of the name.)^
3319: ** ^Parameters of the form "?" without a following integer have no name
3320: ** and are referred to as "nameless" or "anonymous parameters".
3321: **
3322: ** ^The first host parameter has an index of 1, not 0.
3323: **
3324: ** ^If the value N is out of range or if the N-th parameter is
3325: ** nameless, then NULL is returned. ^The returned string is
3326: ** always in UTF-8 encoding even if the named parameter was
3327: ** originally specified as UTF-16 in [sqlite3_prepare16()] or
3328: ** [sqlite3_prepare16_v2()].
3329: **
3330: ** See also: [sqlite3_bind_blob|sqlite3_bind()],
3331: ** [sqlite3_bind_parameter_count()], and
3332: ** [sqlite3_bind_parameter_index()].
3333: */
3334: SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
3335:
3336: /*
3337: ** CAPI3REF: Index Of A Parameter With A Given Name
3338: **
3339: ** ^Return the index of an SQL parameter given its name. ^The
3340: ** index value returned is suitable for use as the second
3341: ** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero
3342: ** is returned if no matching parameter is found. ^The parameter
3343: ** name must be given in UTF-8 even if the original statement
3344: ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()].
3345: **
3346: ** See also: [sqlite3_bind_blob|sqlite3_bind()],
3347: ** [sqlite3_bind_parameter_count()], and
3348: ** [sqlite3_bind_parameter_index()].
3349: */
3350: SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
3351:
3352: /*
3353: ** CAPI3REF: Reset All Bindings On A Prepared Statement
3354: **
3355: ** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
3356: ** the [sqlite3_bind_blob | bindings] on a [prepared statement].
3357: ** ^Use this routine to reset all host parameters to NULL.
3358: */
3359: SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*);
3360:
3361: /*
3362: ** CAPI3REF: Number Of Columns In A Result Set
3363: **
3364: ** ^Return the number of columns in the result set returned by the
3365: ** [prepared statement]. ^This routine returns 0 if pStmt is an SQL
3366: ** statement that does not return data (for example an [UPDATE]).
3367: **
3368: ** See also: [sqlite3_data_count()]
3369: */
3370: SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt);
3371:
3372: /*
3373: ** CAPI3REF: Column Names In A Result Set
3374: **
3375: ** ^These routines return the name assigned to a particular column
3376: ** in the result set of a [SELECT] statement. ^The sqlite3_column_name()
3377: ** interface returns a pointer to a zero-terminated UTF-8 string
3378: ** and sqlite3_column_name16() returns a pointer to a zero-terminated
3379: ** UTF-16 string. ^The first parameter is the [prepared statement]
3380: ** that implements the [SELECT] statement. ^The second parameter is the
3381: ** column number. ^The leftmost column is number 0.
3382: **
3383: ** ^The returned string pointer is valid until either the [prepared statement]
3384: ** is destroyed by [sqlite3_finalize()] or until the statement is automatically
3385: ** reprepared by the first call to [sqlite3_step()] for a particular run
3386: ** or until the next call to
3387: ** sqlite3_column_name() or sqlite3_column_name16() on the same column.
3388: **
3389: ** ^If sqlite3_malloc() fails during the processing of either routine
3390: ** (for example during a conversion from UTF-8 to UTF-16) then a
3391: ** NULL pointer is returned.
3392: **
3393: ** ^The name of a result column is the value of the "AS" clause for
3394: ** that column, if there is an AS clause. If there is no AS clause
3395: ** then the name of the column is unspecified and may change from
3396: ** one release of SQLite to the next.
3397: */
3398: SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N);
3399: SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N);
3400:
3401: /*
3402: ** CAPI3REF: Source Of Data In A Query Result
3403: **
3404: ** ^These routines provide a means to determine the database, table, and
3405: ** table column that is the origin of a particular result column in
3406: ** [SELECT] statement.
3407: ** ^The name of the database or table or column can be returned as
3408: ** either a UTF-8 or UTF-16 string. ^The _database_ routines return
3409: ** the database name, the _table_ routines return the table name, and
3410: ** the origin_ routines return the column name.
3411: ** ^The returned string is valid until the [prepared statement] is destroyed
3412: ** using [sqlite3_finalize()] or until the statement is automatically
3413: ** reprepared by the first call to [sqlite3_step()] for a particular run
3414: ** or until the same information is requested
3415: ** again in a different encoding.
3416: **
3417: ** ^The names returned are the original un-aliased names of the
3418: ** database, table, and column.
3419: **
3420: ** ^The first argument to these interfaces is a [prepared statement].
3421: ** ^These functions return information about the Nth result column returned by
3422: ** the statement, where N is the second function argument.
3423: ** ^The left-most column is column 0 for these routines.
3424: **
3425: ** ^If the Nth column returned by the statement is an expression or
3426: ** subquery and is not a column value, then all of these functions return
3427: ** NULL. ^These routine might also return NULL if a memory allocation error
3428: ** occurs. ^Otherwise, they return the name of the attached database, table,
3429: ** or column that query result column was extracted from.
3430: **
3431: ** ^As with all other SQLite APIs, those whose names end with "16" return
3432: ** UTF-16 encoded strings and the other functions return UTF-8.
3433: **
3434: ** ^These APIs are only available if the library was compiled with the
3435: ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
3436: **
3437: ** If two or more threads call one or more of these routines against the same
3438: ** prepared statement and column at the same time then the results are
3439: ** undefined.
3440: **
3441: ** If two or more threads call one or more
3442: ** [sqlite3_column_database_name | column metadata interfaces]
3443: ** for the same [prepared statement] and result column
3444: ** at the same time then the results are undefined.
3445: */
3446: SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int);
3447: SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
3448: SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int);
3449: SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
3450: SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
3451: SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
3452:
3453: /*
3454: ** CAPI3REF: Declared Datatype Of A Query Result
3455: **
3456: ** ^(The first parameter is a [prepared statement].
3457: ** If this statement is a [SELECT] statement and the Nth column of the
3458: ** returned result set of that [SELECT] is a table column (not an
3459: ** expression or subquery) then the declared type of the table
3460: ** column is returned.)^ ^If the Nth column of the result set is an
3461: ** expression or subquery, then a NULL pointer is returned.
3462: ** ^The returned string is always UTF-8 encoded.
3463: **
3464: ** ^(For example, given the database schema:
3465: **
3466: ** CREATE TABLE t1(c1 VARIANT);
3467: **
3468: ** and the following statement to be compiled:
3469: **
3470: ** SELECT c1 + 1, c1 FROM t1;
3471: **
3472: ** this routine would return the string "VARIANT" for the second result
3473: ** column (i==1), and a NULL pointer for the first result column (i==0).)^
3474: **
3475: ** ^SQLite uses dynamic run-time typing. ^So just because a column
3476: ** is declared to contain a particular type does not mean that the
3477: ** data stored in that column is of the declared type. SQLite is
3478: ** strongly typed, but the typing is dynamic not static. ^Type
3479: ** is associated with individual values, not with the containers
3480: ** used to hold those values.
3481: */
3482: SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int);
3483: SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
3484:
3485: /*
3486: ** CAPI3REF: Evaluate An SQL Statement
3487: **
3488: ** After a [prepared statement] has been prepared using either
3489: ** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy
3490: ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
3491: ** must be called one or more times to evaluate the statement.
3492: **
3493: ** The details of the behavior of the sqlite3_step() interface depend
3494: ** on whether the statement was prepared using the newer "v2" interface
3495: ** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy
3496: ** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the
3497: ** new "v2" interface is recommended for new applications but the legacy
3498: ** interface will continue to be supported.
3499: **
3500: ** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
3501: ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
3502: ** ^With the "v2" interface, any of the other [result codes] or
3503: ** [extended result codes] might be returned as well.
3504: **
3505: ** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
3506: ** database locks it needs to do its job. ^If the statement is a [COMMIT]
3507: ** or occurs outside of an explicit transaction, then you can retry the
3508: ** statement. If the statement is not a [COMMIT] and occurs within an
3509: ** explicit transaction then you should rollback the transaction before
3510: ** continuing.
3511: **
3512: ** ^[SQLITE_DONE] means that the statement has finished executing
3513: ** successfully. sqlite3_step() should not be called again on this virtual
3514: ** machine without first calling [sqlite3_reset()] to reset the virtual
3515: ** machine back to its initial state.
3516: **
3517: ** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
3518: ** is returned each time a new row of data is ready for processing by the
3519: ** caller. The values may be accessed using the [column access functions].
3520: ** sqlite3_step() is called again to retrieve the next row of data.
3521: **
3522: ** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
3523: ** violation) has occurred. sqlite3_step() should not be called again on
3524: ** the VM. More information may be found by calling [sqlite3_errmsg()].
3525: ** ^With the legacy interface, a more specific error code (for example,
3526: ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
3527: ** can be obtained by calling [sqlite3_reset()] on the
3528: ** [prepared statement]. ^In the "v2" interface,
3529: ** the more specific error code is returned directly by sqlite3_step().
3530: **
3531: ** [SQLITE_MISUSE] means that the this routine was called inappropriately.
3532: ** Perhaps it was called on a [prepared statement] that has
3533: ** already been [sqlite3_finalize | finalized] or on one that had
3534: ** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could
3535: ** be the case that the same database connection is being used by two or
3536: ** more threads at the same moment in time.
3537: **
3538: ** For all versions of SQLite up to and including 3.6.23.1, a call to
3539: ** [sqlite3_reset()] was required after sqlite3_step() returned anything
3540: ** other than [SQLITE_ROW] before any subsequent invocation of
3541: ** sqlite3_step(). Failure to reset the prepared statement using
3542: ** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
3543: ** sqlite3_step(). But after version 3.6.23.1, sqlite3_step() began
3544: ** calling [sqlite3_reset()] automatically in this circumstance rather
3545: ** than returning [SQLITE_MISUSE]. This is not considered a compatibility
3546: ** break because any application that ever receives an SQLITE_MISUSE error
3547: ** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option
3548: ** can be used to restore the legacy behavior.
3549: **
3550: ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
3551: ** API always returns a generic error code, [SQLITE_ERROR], following any
3552: ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call
3553: ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
3554: ** specific [error codes] that better describes the error.
3555: ** We admit that this is a goofy design. The problem has been fixed
3556: ** with the "v2" interface. If you prepare all of your SQL statements
3557: ** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead
3558: ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
3559: ** then the more specific [error codes] are returned directly
3560: ** by sqlite3_step(). The use of the "v2" interface is recommended.
3561: */
3562: SQLITE_API int sqlite3_step(sqlite3_stmt*);
3563:
3564: /*
3565: ** CAPI3REF: Number of columns in a result set
3566: **
3567: ** ^The sqlite3_data_count(P) interface returns the number of columns in the
3568: ** current row of the result set of [prepared statement] P.
3569: ** ^If prepared statement P does not have results ready to return
3570: ** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of
3571: ** interfaces) then sqlite3_data_count(P) returns 0.
3572: ** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
3573: ** ^The sqlite3_data_count(P) routine returns 0 if the previous call to
3574: ** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P)
3575: ** will return non-zero if previous call to [sqlite3_step](P) returned
3576: ** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum]
3577: ** where it always returns zero since each step of that multi-step
3578: ** pragma returns 0 columns of data.
3579: **
3580: ** See also: [sqlite3_column_count()]
3581: */
3582: SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
3583:
3584: /*
3585: ** CAPI3REF: Fundamental Datatypes
3586: ** KEYWORDS: SQLITE_TEXT
3587: **
3588: ** ^(Every value in SQLite has one of five fundamental datatypes:
3589: **
3590: ** <ul>
3591: ** <li> 64-bit signed integer
3592: ** <li> 64-bit IEEE floating point number
3593: ** <li> string
3594: ** <li> BLOB
3595: ** <li> NULL
3596: ** </ul>)^
3597: **
3598: ** These constants are codes for each of those types.
3599: **
3600: ** Note that the SQLITE_TEXT constant was also used in SQLite version 2
3601: ** for a completely different meaning. Software that links against both
3602: ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
3603: ** SQLITE_TEXT.
3604: */
3605: #define SQLITE_INTEGER 1
3606: #define SQLITE_FLOAT 2
3607: #define SQLITE_BLOB 4
3608: #define SQLITE_NULL 5
3609: #ifdef SQLITE_TEXT
3610: # undef SQLITE_TEXT
3611: #else
3612: # define SQLITE_TEXT 3
3613: #endif
3614: #define SQLITE3_TEXT 3
3615:
3616: /*
3617: ** CAPI3REF: Result Values From A Query
3618: ** KEYWORDS: {column access functions}
3619: **
3620: ** These routines form the "result set" interface.
3621: **
3622: ** ^These routines return information about a single column of the current
3623: ** result row of a query. ^In every case the first argument is a pointer
3624: ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
3625: ** that was returned from [sqlite3_prepare_v2()] or one of its variants)
3626: ** and the second argument is the index of the column for which information
3627: ** should be returned. ^The leftmost column of the result set has the index 0.
3628: ** ^The number of columns in the result can be determined using
3629: ** [sqlite3_column_count()].
3630: **
3631: ** If the SQL statement does not currently point to a valid row, or if the
3632: ** column index is out of range, the result is undefined.
3633: ** These routines may only be called when the most recent call to
3634: ** [sqlite3_step()] has returned [SQLITE_ROW] and neither
3635: ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
3636: ** If any of these routines are called after [sqlite3_reset()] or
3637: ** [sqlite3_finalize()] or after [sqlite3_step()] has returned
3638: ** something other than [SQLITE_ROW], the results are undefined.
3639: ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
3640: ** are called from a different thread while any of these routines
3641: ** are pending, then the results are undefined.
3642: **
3643: ** ^The sqlite3_column_type() routine returns the
3644: ** [SQLITE_INTEGER | datatype code] for the initial data type
3645: ** of the result column. ^The returned value is one of [SQLITE_INTEGER],
3646: ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value
3647: ** returned by sqlite3_column_type() is only meaningful if no type
3648: ** conversions have occurred as described below. After a type conversion,
3649: ** the value returned by sqlite3_column_type() is undefined. Future
3650: ** versions of SQLite may change the behavior of sqlite3_column_type()
3651: ** following a type conversion.
3652: **
3653: ** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
3654: ** routine returns the number of bytes in that BLOB or string.
3655: ** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
3656: ** the string to UTF-8 and then returns the number of bytes.
3657: ** ^If the result is a numeric value then sqlite3_column_bytes() uses
3658: ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
3659: ** the number of bytes in that string.
3660: ** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
3661: **
3662: ** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
3663: ** routine returns the number of bytes in that BLOB or string.
3664: ** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
3665: ** the string to UTF-16 and then returns the number of bytes.
3666: ** ^If the result is a numeric value then sqlite3_column_bytes16() uses
3667: ** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
3668: ** the number of bytes in that string.
3669: ** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
3670: **
3671: ** ^The values returned by [sqlite3_column_bytes()] and
3672: ** [sqlite3_column_bytes16()] do not include the zero terminators at the end
3673: ** of the string. ^For clarity: the values returned by
3674: ** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
3675: ** bytes in the string, not the number of characters.
3676: **
3677: ** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
3678: ** even empty strings, are always zero-terminated. ^The return
3679: ** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
3680: **
3681: ** ^The object returned by [sqlite3_column_value()] is an
3682: ** [unprotected sqlite3_value] object. An unprotected sqlite3_value object
3683: ** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()].
3684: ** If the [unprotected sqlite3_value] object returned by
3685: ** [sqlite3_column_value()] is used in any other way, including calls
3686: ** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
3687: ** or [sqlite3_value_bytes()], then the behavior is undefined.
3688: **
3689: ** These routines attempt to convert the value where appropriate. ^For
3690: ** example, if the internal representation is FLOAT and a text result
3691: ** is requested, [sqlite3_snprintf()] is used internally to perform the
3692: ** conversion automatically. ^(The following table details the conversions
3693: ** that are applied:
3694: **
3695: ** <blockquote>
3696: ** <table border="1">
3697: ** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion
3698: **
3699: ** <tr><td> NULL <td> INTEGER <td> Result is 0
3700: ** <tr><td> NULL <td> FLOAT <td> Result is 0.0
3701: ** <tr><td> NULL <td> TEXT <td> Result is NULL pointer
3702: ** <tr><td> NULL <td> BLOB <td> Result is NULL pointer
3703: ** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float
3704: ** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer
3705: ** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT
3706: ** <tr><td> FLOAT <td> INTEGER <td> Convert from float to integer
3707: ** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float
3708: ** <tr><td> FLOAT <td> BLOB <td> Same as FLOAT->TEXT
3709: ** <tr><td> TEXT <td> INTEGER <td> Use atoi()
3710: ** <tr><td> TEXT <td> FLOAT <td> Use atof()
3711: ** <tr><td> TEXT <td> BLOB <td> No change
3712: ** <tr><td> BLOB <td> INTEGER <td> Convert to TEXT then use atoi()
3713: ** <tr><td> BLOB <td> FLOAT <td> Convert to TEXT then use atof()
3714: ** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed
3715: ** </table>
3716: ** </blockquote>)^
3717: **
3718: ** The table above makes reference to standard C library functions atoi()
3719: ** and atof(). SQLite does not really use these functions. It has its
3720: ** own equivalent internal routines. The atoi() and atof() names are
3721: ** used in the table for brevity and because they are familiar to most
3722: ** C programmers.
3723: **
3724: ** Note that when type conversions occur, pointers returned by prior
3725: ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
3726: ** sqlite3_column_text16() may be invalidated.
3727: ** Type conversions and pointer invalidations might occur
3728: ** in the following cases:
3729: **
3730: ** <ul>
3731: ** <li> The initial content is a BLOB and sqlite3_column_text() or
3732: ** sqlite3_column_text16() is called. A zero-terminator might
3733: ** need to be added to the string.</li>
3734: ** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
3735: ** sqlite3_column_text16() is called. The content must be converted
3736: ** to UTF-16.</li>
3737: ** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
3738: ** sqlite3_column_text() is called. The content must be converted
3739: ** to UTF-8.</li>
3740: ** </ul>
3741: **
3742: ** ^Conversions between UTF-16be and UTF-16le are always done in place and do
3743: ** not invalidate a prior pointer, though of course the content of the buffer
3744: ** that the prior pointer references will have been modified. Other kinds
3745: ** of conversion are done in place when it is possible, but sometimes they
3746: ** are not possible and in those cases prior pointers are invalidated.
3747: **
3748: ** The safest and easiest to remember policy is to invoke these routines
3749: ** in one of the following ways:
3750: **
3751: ** <ul>
3752: ** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
3753: ** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
3754: ** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
3755: ** </ul>
3756: **
3757: ** In other words, you should call sqlite3_column_text(),
3758: ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
3759: ** into the desired format, then invoke sqlite3_column_bytes() or
3760: ** sqlite3_column_bytes16() to find the size of the result. Do not mix calls
3761: ** to sqlite3_column_text() or sqlite3_column_blob() with calls to
3762: ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
3763: ** with calls to sqlite3_column_bytes().
3764: **
3765: ** ^The pointers returned are valid until a type conversion occurs as
3766: ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
3767: ** [sqlite3_finalize()] is called. ^The memory space used to hold strings
3768: ** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned
3769: ** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
3770: ** [sqlite3_free()].
3771: **
3772: ** ^(If a memory allocation error occurs during the evaluation of any
3773: ** of these routines, a default value is returned. The default value
3774: ** is either the integer 0, the floating point number 0.0, or a NULL
3775: ** pointer. Subsequent calls to [sqlite3_errcode()] will return
3776: ** [SQLITE_NOMEM].)^
3777: */
3778: SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
3779: SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
3780: SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
3781: SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol);
3782: SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol);
3783: SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
3784: SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
3785: SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
3786: SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol);
3787: SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
3788:
3789: /*
3790: ** CAPI3REF: Destroy A Prepared Statement Object
3791: **
3792: ** ^The sqlite3_finalize() function is called to delete a [prepared statement].
3793: ** ^If the most recent evaluation of the statement encountered no errors
3794: ** or if the statement is never been evaluated, then sqlite3_finalize() returns
3795: ** SQLITE_OK. ^If the most recent evaluation of statement S failed, then
3796: ** sqlite3_finalize(S) returns the appropriate [error code] or
3797: ** [extended error code].
3798: **
3799: ** ^The sqlite3_finalize(S) routine can be called at any point during
3800: ** the life cycle of [prepared statement] S:
3801: ** before statement S is ever evaluated, after
3802: ** one or more calls to [sqlite3_reset()], or after any call
3803: ** to [sqlite3_step()] regardless of whether or not the statement has
3804: ** completed execution.
3805: **
3806: ** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
3807: **
3808: ** The application must finalize every [prepared statement] in order to avoid
3809: ** resource leaks. It is a grievous error for the application to try to use
3810: ** a prepared statement after it has been finalized. Any use of a prepared
3811: ** statement after it has been finalized can result in undefined and
3812: ** undesirable behavior such as segfaults and heap corruption.
3813: */
3814: SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt);
3815:
3816: /*
3817: ** CAPI3REF: Reset A Prepared Statement Object
3818: **
3819: ** The sqlite3_reset() function is called to reset a [prepared statement]
3820: ** object back to its initial state, ready to be re-executed.
3821: ** ^Any SQL statement variables that had values bound to them using
3822: ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
3823: ** Use [sqlite3_clear_bindings()] to reset the bindings.
3824: **
3825: ** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
3826: ** back to the beginning of its program.
3827: **
3828: ** ^If the most recent call to [sqlite3_step(S)] for the
3829: ** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
3830: ** or if [sqlite3_step(S)] has never before been called on S,
3831: ** then [sqlite3_reset(S)] returns [SQLITE_OK].
3832: **
3833: ** ^If the most recent call to [sqlite3_step(S)] for the
3834: ** [prepared statement] S indicated an error, then
3835: ** [sqlite3_reset(S)] returns an appropriate [error code].
3836: **
3837: ** ^The [sqlite3_reset(S)] interface does not change the values
3838: ** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
3839: */
3840: SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt);
3841:
3842: /*
3843: ** CAPI3REF: Create Or Redefine SQL Functions
3844: ** KEYWORDS: {function creation routines}
3845: ** KEYWORDS: {application-defined SQL function}
3846: ** KEYWORDS: {application-defined SQL functions}
3847: **
3848: ** ^These functions (collectively known as "function creation routines")
3849: ** are used to add SQL functions or aggregates or to redefine the behavior
3850: ** of existing SQL functions or aggregates. The only differences between
3851: ** these routines are the text encoding expected for
3852: ** the second parameter (the name of the function being created)
3853: ** and the presence or absence of a destructor callback for
3854: ** the application data pointer.
3855: **
3856: ** ^The first parameter is the [database connection] to which the SQL
3857: ** function is to be added. ^If an application uses more than one database
3858: ** connection then application-defined SQL functions must be added
3859: ** to each database connection separately.
3860: **
3861: ** ^The second parameter is the name of the SQL function to be created or
3862: ** redefined. ^The length of the name is limited to 255 bytes in a UTF-8
3863: ** representation, exclusive of the zero-terminator. ^Note that the name
3864: ** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
3865: ** ^Any attempt to create a function with a longer name
3866: ** will result in [SQLITE_MISUSE] being returned.
3867: **
3868: ** ^The third parameter (nArg)
3869: ** is the number of arguments that the SQL function or
3870: ** aggregate takes. ^If this parameter is -1, then the SQL function or
3871: ** aggregate may take any number of arguments between 0 and the limit
3872: ** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third
3873: ** parameter is less than -1 or greater than 127 then the behavior is
3874: ** undefined.
3875: **
3876: ** ^The fourth parameter, eTextRep, specifies what
3877: ** [SQLITE_UTF8 | text encoding] this SQL function prefers for
3878: ** its parameters. Every SQL function implementation must be able to work
3879: ** with UTF-8, UTF-16le, or UTF-16be. But some implementations may be
3880: ** more efficient with one encoding than another. ^An application may
3881: ** invoke sqlite3_create_function() or sqlite3_create_function16() multiple
3882: ** times with the same function but with different values of eTextRep.
3883: ** ^When multiple implementations of the same function are available, SQLite
3884: ** will pick the one that involves the least amount of data conversion.
3885: ** If there is only a single implementation which does not care what text
3886: ** encoding is used, then the fourth argument should be [SQLITE_ANY].
3887: **
3888: ** ^(The fifth parameter is an arbitrary pointer. The implementation of the
3889: ** function can gain access to this pointer using [sqlite3_user_data()].)^
3890: **
3891: ** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are
3892: ** pointers to C-language functions that implement the SQL function or
3893: ** aggregate. ^A scalar SQL function requires an implementation of the xFunc
3894: ** callback only; NULL pointers must be passed as the xStep and xFinal
3895: ** parameters. ^An aggregate SQL function requires an implementation of xStep
3896: ** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
3897: ** SQL function or aggregate, pass NULL pointers for all three function
3898: ** callbacks.
3899: **
3900: ** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL,
3901: ** then it is destructor for the application data pointer.
3902: ** The destructor is invoked when the function is deleted, either by being
3903: ** overloaded or when the database connection closes.)^
3904: ** ^The destructor is also invoked if the call to
3905: ** sqlite3_create_function_v2() fails.
3906: ** ^When the destructor callback of the tenth parameter is invoked, it
3907: ** is passed a single argument which is a copy of the application data
3908: ** pointer which was the fifth parameter to sqlite3_create_function_v2().
3909: **
3910: ** ^It is permitted to register multiple implementations of the same
3911: ** functions with the same name but with either differing numbers of
3912: ** arguments or differing preferred text encodings. ^SQLite will use
3913: ** the implementation that most closely matches the way in which the
3914: ** SQL function is used. ^A function implementation with a non-negative
3915: ** nArg parameter is a better match than a function implementation with
3916: ** a negative nArg. ^A function where the preferred text encoding
3917: ** matches the database encoding is a better
3918: ** match than a function where the encoding is different.
3919: ** ^A function where the encoding difference is between UTF16le and UTF16be
3920: ** is a closer match than a function where the encoding difference is
3921: ** between UTF8 and UTF16.
3922: **
3923: ** ^Built-in functions may be overloaded by new application-defined functions.
3924: **
3925: ** ^An application-defined function is permitted to call other
3926: ** SQLite interfaces. However, such calls must not
3927: ** close the database connection nor finalize or reset the prepared
3928: ** statement in which the function is running.
3929: */
3930: SQLITE_API int sqlite3_create_function(
3931: sqlite3 *db,
3932: const char *zFunctionName,
3933: int nArg,
3934: int eTextRep,
3935: void *pApp,
3936: void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
3937: void (*xStep)(sqlite3_context*,int,sqlite3_value**),
3938: void (*xFinal)(sqlite3_context*)
3939: );
3940: SQLITE_API int sqlite3_create_function16(
3941: sqlite3 *db,
3942: const void *zFunctionName,
3943: int nArg,
3944: int eTextRep,
3945: void *pApp,
3946: void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
3947: void (*xStep)(sqlite3_context*,int,sqlite3_value**),
3948: void (*xFinal)(sqlite3_context*)
3949: );
3950: SQLITE_API int sqlite3_create_function_v2(
3951: sqlite3 *db,
3952: const char *zFunctionName,
3953: int nArg,
3954: int eTextRep,
3955: void *pApp,
3956: void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
3957: void (*xStep)(sqlite3_context*,int,sqlite3_value**),
3958: void (*xFinal)(sqlite3_context*),
3959: void(*xDestroy)(void*)
3960: );
3961:
3962: /*
3963: ** CAPI3REF: Text Encodings
3964: **
3965: ** These constant define integer codes that represent the various
3966: ** text encodings supported by SQLite.
3967: */
3968: #define SQLITE_UTF8 1
3969: #define SQLITE_UTF16LE 2
3970: #define SQLITE_UTF16BE 3
3971: #define SQLITE_UTF16 4 /* Use native byte order */
3972: #define SQLITE_ANY 5 /* sqlite3_create_function only */
3973: #define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */
3974:
3975: /*
3976: ** CAPI3REF: Deprecated Functions
3977: ** DEPRECATED
3978: **
3979: ** These functions are [deprecated]. In order to maintain
3980: ** backwards compatibility with older code, these functions continue
3981: ** to be supported. However, new applications should avoid
3982: ** the use of these functions. To help encourage people to avoid
3983: ** using these functions, we are not going to tell you what they do.
3984: */
3985: #ifndef SQLITE_OMIT_DEPRECATED
3986: SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
3987: SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
3988: SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
3989: SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void);
3990: SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
3991: SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64);
3992: #endif
3993:
3994: /*
3995: ** CAPI3REF: Obtaining SQL Function Parameter Values
3996: **
3997: ** The C-language implementation of SQL functions and aggregates uses
3998: ** this set of interface routines to access the parameter values on
3999: ** the function or aggregate.
4000: **
4001: ** The xFunc (for scalar functions) or xStep (for aggregates) parameters
4002: ** to [sqlite3_create_function()] and [sqlite3_create_function16()]
4003: ** define callbacks that implement the SQL functions and aggregates.
4004: ** The 3rd parameter to these callbacks is an array of pointers to
4005: ** [protected sqlite3_value] objects. There is one [sqlite3_value] object for
4006: ** each parameter to the SQL function. These routines are used to
4007: ** extract values from the [sqlite3_value] objects.
4008: **
4009: ** These routines work only with [protected sqlite3_value] objects.
4010: ** Any attempt to use these routines on an [unprotected sqlite3_value]
4011: ** object results in undefined behavior.
4012: **
4013: ** ^These routines work just like the corresponding [column access functions]
4014: ** except that these routines take a single [protected sqlite3_value] object
4015: ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
4016: **
4017: ** ^The sqlite3_value_text16() interface extracts a UTF-16 string
4018: ** in the native byte-order of the host machine. ^The
4019: ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
4020: ** extract UTF-16 strings as big-endian and little-endian respectively.
4021: **
4022: ** ^(The sqlite3_value_numeric_type() interface attempts to apply
4023: ** numeric affinity to the value. This means that an attempt is
4024: ** made to convert the value to an integer or floating point. If
4025: ** such a conversion is possible without loss of information (in other
4026: ** words, if the value is a string that looks like a number)
4027: ** then the conversion is performed. Otherwise no conversion occurs.
4028: ** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
4029: **
4030: ** Please pay particular attention to the fact that the pointer returned
4031: ** from [sqlite3_value_blob()], [sqlite3_value_text()], or
4032: ** [sqlite3_value_text16()] can be invalidated by a subsequent call to
4033: ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
4034: ** or [sqlite3_value_text16()].
4035: **
4036: ** These routines must be called from the same thread as
4037: ** the SQL function that supplied the [sqlite3_value*] parameters.
4038: */
4039: SQLITE_API const void *sqlite3_value_blob(sqlite3_value*);
4040: SQLITE_API int sqlite3_value_bytes(sqlite3_value*);
4041: SQLITE_API int sqlite3_value_bytes16(sqlite3_value*);
4042: SQLITE_API double sqlite3_value_double(sqlite3_value*);
4043: SQLITE_API int sqlite3_value_int(sqlite3_value*);
4044: SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
4045: SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*);
4046: SQLITE_API const void *sqlite3_value_text16(sqlite3_value*);
4047: SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*);
4048: SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*);
4049: SQLITE_API int sqlite3_value_type(sqlite3_value*);
4050: SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*);
4051:
4052: /*
4053: ** CAPI3REF: Obtain Aggregate Function Context
4054: **
4055: ** Implementations of aggregate SQL functions use this
4056: ** routine to allocate memory for storing their state.
4057: **
4058: ** ^The first time the sqlite3_aggregate_context(C,N) routine is called
4059: ** for a particular aggregate function, SQLite
4060: ** allocates N of memory, zeroes out that memory, and returns a pointer
4061: ** to the new memory. ^On second and subsequent calls to
4062: ** sqlite3_aggregate_context() for the same aggregate function instance,
4063: ** the same buffer is returned. Sqlite3_aggregate_context() is normally
4064: ** called once for each invocation of the xStep callback and then one
4065: ** last time when the xFinal callback is invoked. ^(When no rows match
4066: ** an aggregate query, the xStep() callback of the aggregate function
4067: ** implementation is never called and xFinal() is called exactly once.
4068: ** In those cases, sqlite3_aggregate_context() might be called for the
4069: ** first time from within xFinal().)^
4070: **
4071: ** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer if N is
4072: ** less than or equal to zero or if a memory allocate error occurs.
4073: **
4074: ** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
4075: ** determined by the N parameter on first successful call. Changing the
4076: ** value of N in subsequent call to sqlite3_aggregate_context() within
4077: ** the same aggregate function instance will not resize the memory
4078: ** allocation.)^
4079: **
4080: ** ^SQLite automatically frees the memory allocated by
4081: ** sqlite3_aggregate_context() when the aggregate query concludes.
4082: **
4083: ** The first parameter must be a copy of the
4084: ** [sqlite3_context | SQL function context] that is the first parameter
4085: ** to the xStep or xFinal callback routine that implements the aggregate
4086: ** function.
4087: **
4088: ** This routine must be called from the same thread in which
4089: ** the aggregate SQL function is running.
4090: */
4091: SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
4092:
4093: /*
4094: ** CAPI3REF: User Data For Functions
4095: **
4096: ** ^The sqlite3_user_data() interface returns a copy of
4097: ** the pointer that was the pUserData parameter (the 5th parameter)
4098: ** of the [sqlite3_create_function()]
4099: ** and [sqlite3_create_function16()] routines that originally
4100: ** registered the application defined function.
4101: **
4102: ** This routine must be called from the same thread in which
4103: ** the application-defined function is running.
4104: */
4105: SQLITE_API void *sqlite3_user_data(sqlite3_context*);
4106:
4107: /*
4108: ** CAPI3REF: Database Connection For Functions
4109: **
4110: ** ^The sqlite3_context_db_handle() interface returns a copy of
4111: ** the pointer to the [database connection] (the 1st parameter)
4112: ** of the [sqlite3_create_function()]
4113: ** and [sqlite3_create_function16()] routines that originally
4114: ** registered the application defined function.
4115: */
4116: SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
4117:
4118: /*
4119: ** CAPI3REF: Function Auxiliary Data
4120: **
4121: ** The following two functions may be used by scalar SQL functions to
4122: ** associate metadata with argument values. If the same value is passed to
4123: ** multiple invocations of the same SQL function during query execution, under
4124: ** some circumstances the associated metadata may be preserved. This may
4125: ** be used, for example, to add a regular-expression matching scalar
4126: ** function. The compiled version of the regular expression is stored as
4127: ** metadata associated with the SQL value passed as the regular expression
4128: ** pattern. The compiled regular expression can be reused on multiple
4129: ** invocations of the same function so that the original pattern string
4130: ** does not need to be recompiled on each invocation.
4131: **
4132: ** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata
4133: ** associated by the sqlite3_set_auxdata() function with the Nth argument
4134: ** value to the application-defined function. ^If no metadata has been ever
4135: ** been set for the Nth argument of the function, or if the corresponding
4136: ** function parameter has changed since the meta-data was set,
4137: ** then sqlite3_get_auxdata() returns a NULL pointer.
4138: **
4139: ** ^The sqlite3_set_auxdata() interface saves the metadata
4140: ** pointed to by its 3rd parameter as the metadata for the N-th
4141: ** argument of the application-defined function. Subsequent
4142: ** calls to sqlite3_get_auxdata() might return this data, if it has
4143: ** not been destroyed.
4144: ** ^If it is not NULL, SQLite will invoke the destructor
4145: ** function given by the 4th parameter to sqlite3_set_auxdata() on
4146: ** the metadata when the corresponding function parameter changes
4147: ** or when the SQL statement completes, whichever comes first.
4148: **
4149: ** SQLite is free to call the destructor and drop metadata on any
4150: ** parameter of any function at any time. ^The only guarantee is that
4151: ** the destructor will be called before the metadata is dropped.
4152: **
4153: ** ^(In practice, metadata is preserved between function calls for
4154: ** expressions that are constant at compile time. This includes literal
4155: ** values and [parameters].)^
4156: **
4157: ** These routines must be called from the same thread in which
4158: ** the SQL function is running.
4159: */
4160: SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N);
4161: SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
4162:
4163:
4164: /*
4165: ** CAPI3REF: Constants Defining Special Destructor Behavior
4166: **
4167: ** These are special values for the destructor that is passed in as the
4168: ** final argument to routines like [sqlite3_result_blob()]. ^If the destructor
4169: ** argument is SQLITE_STATIC, it means that the content pointer is constant
4170: ** and will never change. It does not need to be destroyed. ^The
4171: ** SQLITE_TRANSIENT value means that the content will likely change in
4172: ** the near future and that SQLite should make its own private copy of
4173: ** the content before returning.
4174: **
4175: ** The typedef is necessary to work around problems in certain
4176: ** C++ compilers. See ticket #2191.
4177: */
4178: typedef void (*sqlite3_destructor_type)(void*);
4179: #define SQLITE_STATIC ((sqlite3_destructor_type)0)
4180: #define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1)
4181:
4182: /*
4183: ** CAPI3REF: Setting The Result Of An SQL Function
4184: **
4185: ** These routines are used by the xFunc or xFinal callbacks that
4186: ** implement SQL functions and aggregates. See
4187: ** [sqlite3_create_function()] and [sqlite3_create_function16()]
4188: ** for additional information.
4189: **
4190: ** These functions work very much like the [parameter binding] family of
4191: ** functions used to bind values to host parameters in prepared statements.
4192: ** Refer to the [SQL parameter] documentation for additional information.
4193: **
4194: ** ^The sqlite3_result_blob() interface sets the result from
4195: ** an application-defined function to be the BLOB whose content is pointed
4196: ** to by the second parameter and which is N bytes long where N is the
4197: ** third parameter.
4198: **
4199: ** ^The sqlite3_result_zeroblob() interfaces set the result of
4200: ** the application-defined function to be a BLOB containing all zero
4201: ** bytes and N bytes in size, where N is the value of the 2nd parameter.
4202: **
4203: ** ^The sqlite3_result_double() interface sets the result from
4204: ** an application-defined function to be a floating point value specified
4205: ** by its 2nd argument.
4206: **
4207: ** ^The sqlite3_result_error() and sqlite3_result_error16() functions
4208: ** cause the implemented SQL function to throw an exception.
4209: ** ^SQLite uses the string pointed to by the
4210: ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
4211: ** as the text of an error message. ^SQLite interprets the error
4212: ** message string from sqlite3_result_error() as UTF-8. ^SQLite
4213: ** interprets the string from sqlite3_result_error16() as UTF-16 in native
4214: ** byte order. ^If the third parameter to sqlite3_result_error()
4215: ** or sqlite3_result_error16() is negative then SQLite takes as the error
4216: ** message all text up through the first zero character.
4217: ** ^If the third parameter to sqlite3_result_error() or
4218: ** sqlite3_result_error16() is non-negative then SQLite takes that many
4219: ** bytes (not characters) from the 2nd parameter as the error message.
4220: ** ^The sqlite3_result_error() and sqlite3_result_error16()
4221: ** routines make a private copy of the error message text before
4222: ** they return. Hence, the calling function can deallocate or
4223: ** modify the text after they return without harm.
4224: ** ^The sqlite3_result_error_code() function changes the error code
4225: ** returned by SQLite as a result of an error in a function. ^By default,
4226: ** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error()
4227: ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
4228: **
1.3 ! misho 4229: ** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an
! 4230: ** error indicating that a string or BLOB is too long to represent.
1.2 misho 4231: **
1.3 ! misho 4232: ** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an
! 4233: ** error indicating that a memory allocation failed.
1.2 misho 4234: **
4235: ** ^The sqlite3_result_int() interface sets the return value
4236: ** of the application-defined function to be the 32-bit signed integer
4237: ** value given in the 2nd argument.
4238: ** ^The sqlite3_result_int64() interface sets the return value
4239: ** of the application-defined function to be the 64-bit signed integer
4240: ** value given in the 2nd argument.
4241: **
4242: ** ^The sqlite3_result_null() interface sets the return value
4243: ** of the application-defined function to be NULL.
4244: **
4245: ** ^The sqlite3_result_text(), sqlite3_result_text16(),
4246: ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
4247: ** set the return value of the application-defined function to be
4248: ** a text string which is represented as UTF-8, UTF-16 native byte order,
4249: ** UTF-16 little endian, or UTF-16 big endian, respectively.
4250: ** ^SQLite takes the text result from the application from
4251: ** the 2nd parameter of the sqlite3_result_text* interfaces.
4252: ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
4253: ** is negative, then SQLite takes result text from the 2nd parameter
4254: ** through the first zero character.
4255: ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
4256: ** is non-negative, then as many bytes (not characters) of the text
4257: ** pointed to by the 2nd parameter are taken as the application-defined
4258: ** function result. If the 3rd parameter is non-negative, then it
4259: ** must be the byte offset into the string where the NUL terminator would
4260: ** appear if the string where NUL terminated. If any NUL characters occur
4261: ** in the string at a byte offset that is less than the value of the 3rd
4262: ** parameter, then the resulting string will contain embedded NULs and the
4263: ** result of expressions operating on strings with embedded NULs is undefined.
4264: ** ^If the 4th parameter to the sqlite3_result_text* interfaces
4265: ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
4266: ** function as the destructor on the text or BLOB result when it has
4267: ** finished using that result.
4268: ** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
4269: ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
4270: ** assumes that the text or BLOB result is in constant space and does not
4271: ** copy the content of the parameter nor call a destructor on the content
4272: ** when it has finished using that result.
4273: ** ^If the 4th parameter to the sqlite3_result_text* interfaces
4274: ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
4275: ** then SQLite makes a copy of the result into space obtained from
4276: ** from [sqlite3_malloc()] before it returns.
4277: **
4278: ** ^The sqlite3_result_value() interface sets the result of
4279: ** the application-defined function to be a copy the
4280: ** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The
4281: ** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
4282: ** so that the [sqlite3_value] specified in the parameter may change or
4283: ** be deallocated after sqlite3_result_value() returns without harm.
4284: ** ^A [protected sqlite3_value] object may always be used where an
4285: ** [unprotected sqlite3_value] object is required, so either
4286: ** kind of [sqlite3_value] object can be used with this interface.
4287: **
4288: ** If these routines are called from within the different thread
4289: ** than the one containing the application-defined function that received
4290: ** the [sqlite3_context] pointer, the results are undefined.
4291: */
4292: SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
4293: SQLITE_API void sqlite3_result_double(sqlite3_context*, double);
4294: SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int);
4295: SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int);
4296: SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*);
4297: SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*);
4298: SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int);
4299: SQLITE_API void sqlite3_result_int(sqlite3_context*, int);
4300: SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
4301: SQLITE_API void sqlite3_result_null(sqlite3_context*);
4302: SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
4303: SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
4304: SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
4305: SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
4306: SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
4307: SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n);
4308:
4309: /*
4310: ** CAPI3REF: Define New Collating Sequences
4311: **
4312: ** ^These functions add, remove, or modify a [collation] associated
4313: ** with the [database connection] specified as the first argument.
4314: **
4315: ** ^The name of the collation is a UTF-8 string
4316: ** for sqlite3_create_collation() and sqlite3_create_collation_v2()
4317: ** and a UTF-16 string in native byte order for sqlite3_create_collation16().
4318: ** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
4319: ** considered to be the same name.
4320: **
4321: ** ^(The third argument (eTextRep) must be one of the constants:
4322: ** <ul>
4323: ** <li> [SQLITE_UTF8],
4324: ** <li> [SQLITE_UTF16LE],
4325: ** <li> [SQLITE_UTF16BE],
4326: ** <li> [SQLITE_UTF16], or
4327: ** <li> [SQLITE_UTF16_ALIGNED].
4328: ** </ul>)^
4329: ** ^The eTextRep argument determines the encoding of strings passed
4330: ** to the collating function callback, xCallback.
4331: ** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
4332: ** force strings to be UTF16 with native byte order.
4333: ** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
4334: ** on an even byte address.
4335: **
4336: ** ^The fourth argument, pArg, is an application data pointer that is passed
4337: ** through as the first argument to the collating function callback.
4338: **
4339: ** ^The fifth argument, xCallback, is a pointer to the collating function.
4340: ** ^Multiple collating functions can be registered using the same name but
4341: ** with different eTextRep parameters and SQLite will use whichever
4342: ** function requires the least amount of data transformation.
4343: ** ^If the xCallback argument is NULL then the collating function is
4344: ** deleted. ^When all collating functions having the same name are deleted,
4345: ** that collation is no longer usable.
4346: **
4347: ** ^The collating function callback is invoked with a copy of the pArg
4348: ** application data pointer and with two strings in the encoding specified
4349: ** by the eTextRep argument. The collating function must return an
4350: ** integer that is negative, zero, or positive
4351: ** if the first string is less than, equal to, or greater than the second,
4352: ** respectively. A collating function must always return the same answer
4353: ** given the same inputs. If two or more collating functions are registered
4354: ** to the same collation name (using different eTextRep values) then all
4355: ** must give an equivalent answer when invoked with equivalent strings.
4356: ** The collating function must obey the following properties for all
4357: ** strings A, B, and C:
4358: **
4359: ** <ol>
4360: ** <li> If A==B then B==A.
4361: ** <li> If A==B and B==C then A==C.
4362: ** <li> If A<B THEN B>A.
4363: ** <li> If A<B and B<C then A<C.
4364: ** </ol>
4365: **
4366: ** If a collating function fails any of the above constraints and that
4367: ** collating function is registered and used, then the behavior of SQLite
4368: ** is undefined.
4369: **
4370: ** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
4371: ** with the addition that the xDestroy callback is invoked on pArg when
4372: ** the collating function is deleted.
4373: ** ^Collating functions are deleted when they are overridden by later
4374: ** calls to the collation creation functions or when the
4375: ** [database connection] is closed using [sqlite3_close()].
4376: **
4377: ** ^The xDestroy callback is <u>not</u> called if the
4378: ** sqlite3_create_collation_v2() function fails. Applications that invoke
4379: ** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
4380: ** check the return code and dispose of the application data pointer
4381: ** themselves rather than expecting SQLite to deal with it for them.
4382: ** This is different from every other SQLite interface. The inconsistency
4383: ** is unfortunate but cannot be changed without breaking backwards
4384: ** compatibility.
4385: **
4386: ** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
4387: */
4388: SQLITE_API int sqlite3_create_collation(
4389: sqlite3*,
4390: const char *zName,
4391: int eTextRep,
4392: void *pArg,
4393: int(*xCompare)(void*,int,const void*,int,const void*)
4394: );
4395: SQLITE_API int sqlite3_create_collation_v2(
4396: sqlite3*,
4397: const char *zName,
4398: int eTextRep,
4399: void *pArg,
4400: int(*xCompare)(void*,int,const void*,int,const void*),
4401: void(*xDestroy)(void*)
4402: );
4403: SQLITE_API int sqlite3_create_collation16(
4404: sqlite3*,
4405: const void *zName,
4406: int eTextRep,
4407: void *pArg,
4408: int(*xCompare)(void*,int,const void*,int,const void*)
4409: );
4410:
4411: /*
4412: ** CAPI3REF: Collation Needed Callbacks
4413: **
4414: ** ^To avoid having to register all collation sequences before a database
4415: ** can be used, a single callback function may be registered with the
4416: ** [database connection] to be invoked whenever an undefined collation
4417: ** sequence is required.
4418: **
4419: ** ^If the function is registered using the sqlite3_collation_needed() API,
4420: ** then it is passed the names of undefined collation sequences as strings
4421: ** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
4422: ** the names are passed as UTF-16 in machine native byte order.
4423: ** ^A call to either function replaces the existing collation-needed callback.
4424: **
4425: ** ^(When the callback is invoked, the first argument passed is a copy
4426: ** of the second argument to sqlite3_collation_needed() or
4427: ** sqlite3_collation_needed16(). The second argument is the database
4428: ** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
4429: ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
4430: ** sequence function required. The fourth parameter is the name of the
4431: ** required collation sequence.)^
4432: **
4433: ** The callback function should register the desired collation using
4434: ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
4435: ** [sqlite3_create_collation_v2()].
4436: */
4437: SQLITE_API int sqlite3_collation_needed(
4438: sqlite3*,
4439: void*,
4440: void(*)(void*,sqlite3*,int eTextRep,const char*)
4441: );
4442: SQLITE_API int sqlite3_collation_needed16(
4443: sqlite3*,
4444: void*,
4445: void(*)(void*,sqlite3*,int eTextRep,const void*)
4446: );
4447:
4448: #ifdef SQLITE_HAS_CODEC
4449: /*
4450: ** Specify the key for an encrypted database. This routine should be
4451: ** called right after sqlite3_open().
4452: **
4453: ** The code to implement this API is not available in the public release
4454: ** of SQLite.
4455: */
4456: SQLITE_API int sqlite3_key(
4457: sqlite3 *db, /* Database to be rekeyed */
4458: const void *pKey, int nKey /* The key */
4459: );
4460:
4461: /*
4462: ** Change the key on an open database. If the current database is not
4463: ** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the
4464: ** database is decrypted.
4465: **
4466: ** The code to implement this API is not available in the public release
4467: ** of SQLite.
4468: */
4469: SQLITE_API int sqlite3_rekey(
4470: sqlite3 *db, /* Database to be rekeyed */
4471: const void *pKey, int nKey /* The new key */
4472: );
4473:
4474: /*
4475: ** Specify the activation key for a SEE database. Unless
4476: ** activated, none of the SEE routines will work.
4477: */
4478: SQLITE_API void sqlite3_activate_see(
4479: const char *zPassPhrase /* Activation phrase */
4480: );
4481: #endif
4482:
4483: #ifdef SQLITE_ENABLE_CEROD
4484: /*
4485: ** Specify the activation key for a CEROD database. Unless
4486: ** activated, none of the CEROD routines will work.
4487: */
4488: SQLITE_API void sqlite3_activate_cerod(
4489: const char *zPassPhrase /* Activation phrase */
4490: );
4491: #endif
4492:
4493: /*
4494: ** CAPI3REF: Suspend Execution For A Short Time
4495: **
4496: ** The sqlite3_sleep() function causes the current thread to suspend execution
4497: ** for at least a number of milliseconds specified in its parameter.
4498: **
4499: ** If the operating system does not support sleep requests with
4500: ** millisecond time resolution, then the time will be rounded up to
4501: ** the nearest second. The number of milliseconds of sleep actually
4502: ** requested from the operating system is returned.
4503: **
4504: ** ^SQLite implements this interface by calling the xSleep()
4505: ** method of the default [sqlite3_vfs] object. If the xSleep() method
4506: ** of the default VFS is not implemented correctly, or not implemented at
4507: ** all, then the behavior of sqlite3_sleep() may deviate from the description
4508: ** in the previous paragraphs.
4509: */
4510: SQLITE_API int sqlite3_sleep(int);
4511:
4512: /*
4513: ** CAPI3REF: Name Of The Folder Holding Temporary Files
4514: **
4515: ** ^(If this global variable is made to point to a string which is
4516: ** the name of a folder (a.k.a. directory), then all temporary files
4517: ** created by SQLite when using a built-in [sqlite3_vfs | VFS]
4518: ** will be placed in that directory.)^ ^If this variable
4519: ** is a NULL pointer, then SQLite performs a search for an appropriate
4520: ** temporary file directory.
4521: **
4522: ** It is not safe to read or modify this variable in more than one
4523: ** thread at a time. It is not safe to read or modify this variable
4524: ** if a [database connection] is being used at the same time in a separate
4525: ** thread.
4526: ** It is intended that this variable be set once
4527: ** as part of process initialization and before any SQLite interface
4528: ** routines have been called and that this variable remain unchanged
4529: ** thereafter.
4530: **
4531: ** ^The [temp_store_directory pragma] may modify this variable and cause
4532: ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,
4533: ** the [temp_store_directory pragma] always assumes that any string
4534: ** that this variable points to is held in memory obtained from
4535: ** [sqlite3_malloc] and the pragma may attempt to free that memory
4536: ** using [sqlite3_free].
4537: ** Hence, if this variable is modified directly, either it should be
4538: ** made NULL or made to point to memory obtained from [sqlite3_malloc]
4539: ** or else the use of the [temp_store_directory pragma] should be avoided.
1.3 ! misho 4540: **
! 4541: ** <b>Note to Windows Runtime users:</b> The temporary directory must be set
! 4542: ** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various
! 4543: ** features that require the use of temporary files may fail. Here is an
! 4544: ** example of how to do this using C++ with the Windows Runtime:
! 4545: **
! 4546: ** <blockquote><pre>
! 4547: ** LPCWSTR zPath = Windows::Storage::ApplicationData::Current->
! 4548: ** TemporaryFolder->Path->Data();
! 4549: ** char zPathBuf[MAX_PATH + 1];
! 4550: ** memset(zPathBuf, 0, sizeof(zPathBuf));
! 4551: ** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),
! 4552: ** NULL, NULL);
! 4553: ** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);
! 4554: ** </pre></blockquote>
1.2 misho 4555: */
4556: SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory;
4557:
4558: /*
1.3 ! misho 4559: ** CAPI3REF: Name Of The Folder Holding Database Files
! 4560: **
! 4561: ** ^(If this global variable is made to point to a string which is
! 4562: ** the name of a folder (a.k.a. directory), then all database files
! 4563: ** specified with a relative pathname and created or accessed by
! 4564: ** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed
! 4565: ** to be relative to that directory.)^ ^If this variable is a NULL
! 4566: ** pointer, then SQLite assumes that all database files specified
! 4567: ** with a relative pathname are relative to the current directory
! 4568: ** for the process. Only the windows VFS makes use of this global
! 4569: ** variable; it is ignored by the unix VFS.
! 4570: **
! 4571: ** Changing the value of this variable while a database connection is
! 4572: ** open can result in a corrupt database.
! 4573: **
! 4574: ** It is not safe to read or modify this variable in more than one
! 4575: ** thread at a time. It is not safe to read or modify this variable
! 4576: ** if a [database connection] is being used at the same time in a separate
! 4577: ** thread.
! 4578: ** It is intended that this variable be set once
! 4579: ** as part of process initialization and before any SQLite interface
! 4580: ** routines have been called and that this variable remain unchanged
! 4581: ** thereafter.
! 4582: **
! 4583: ** ^The [data_store_directory pragma] may modify this variable and cause
! 4584: ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,
! 4585: ** the [data_store_directory pragma] always assumes that any string
! 4586: ** that this variable points to is held in memory obtained from
! 4587: ** [sqlite3_malloc] and the pragma may attempt to free that memory
! 4588: ** using [sqlite3_free].
! 4589: ** Hence, if this variable is modified directly, either it should be
! 4590: ** made NULL or made to point to memory obtained from [sqlite3_malloc]
! 4591: ** or else the use of the [data_store_directory pragma] should be avoided.
! 4592: */
! 4593: SQLITE_API SQLITE_EXTERN char *sqlite3_data_directory;
! 4594:
! 4595: /*
1.2 misho 4596: ** CAPI3REF: Test For Auto-Commit Mode
4597: ** KEYWORDS: {autocommit mode}
4598: **
4599: ** ^The sqlite3_get_autocommit() interface returns non-zero or
4600: ** zero if the given database connection is or is not in autocommit mode,
4601: ** respectively. ^Autocommit mode is on by default.
4602: ** ^Autocommit mode is disabled by a [BEGIN] statement.
4603: ** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
4604: **
4605: ** If certain kinds of errors occur on a statement within a multi-statement
4606: ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
4607: ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
4608: ** transaction might be rolled back automatically. The only way to
4609: ** find out whether SQLite automatically rolled back the transaction after
4610: ** an error is to use this function.
4611: **
4612: ** If another thread changes the autocommit status of the database
4613: ** connection while this routine is running, then the return value
4614: ** is undefined.
4615: */
4616: SQLITE_API int sqlite3_get_autocommit(sqlite3*);
4617:
4618: /*
4619: ** CAPI3REF: Find The Database Handle Of A Prepared Statement
4620: **
4621: ** ^The sqlite3_db_handle interface returns the [database connection] handle
4622: ** to which a [prepared statement] belongs. ^The [database connection]
4623: ** returned by sqlite3_db_handle is the same [database connection]
4624: ** that was the first argument
4625: ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
4626: ** create the statement in the first place.
4627: */
4628: SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
4629:
4630: /*
4631: ** CAPI3REF: Return The Filename For A Database Connection
4632: **
4633: ** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename
4634: ** associated with database N of connection D. ^The main database file
4635: ** has the name "main". If there is no attached database N on the database
4636: ** connection D, or if database N is a temporary or in-memory database, then
4637: ** a NULL pointer is returned.
4638: **
4639: ** ^The filename returned by this function is the output of the
4640: ** xFullPathname method of the [VFS]. ^In other words, the filename
4641: ** will be an absolute pathname, even if the filename used
4642: ** to open the database originally was a URI or relative pathname.
4643: */
4644: SQLITE_API const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName);
4645:
4646: /*
1.3 ! misho 4647: ** CAPI3REF: Determine if a database is read-only
! 4648: **
! 4649: ** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N
! 4650: ** of connection D is read-only, 0 if it is read/write, or -1 if N is not
! 4651: ** the name of a database on connection D.
! 4652: */
! 4653: SQLITE_API int sqlite3_db_readonly(sqlite3 *db, const char *zDbName);
! 4654:
! 4655: /*
1.2 misho 4656: ** CAPI3REF: Find the next prepared statement
4657: **
4658: ** ^This interface returns a pointer to the next [prepared statement] after
4659: ** pStmt associated with the [database connection] pDb. ^If pStmt is NULL
4660: ** then this interface returns a pointer to the first prepared statement
4661: ** associated with the database connection pDb. ^If no prepared statement
4662: ** satisfies the conditions of this routine, it returns NULL.
4663: **
4664: ** The [database connection] pointer D in a call to
4665: ** [sqlite3_next_stmt(D,S)] must refer to an open database
4666: ** connection and in particular must not be a NULL pointer.
4667: */
4668: SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
4669:
4670: /*
4671: ** CAPI3REF: Commit And Rollback Notification Callbacks
4672: **
4673: ** ^The sqlite3_commit_hook() interface registers a callback
4674: ** function to be invoked whenever a transaction is [COMMIT | committed].
4675: ** ^Any callback set by a previous call to sqlite3_commit_hook()
4676: ** for the same database connection is overridden.
4677: ** ^The sqlite3_rollback_hook() interface registers a callback
4678: ** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
4679: ** ^Any callback set by a previous call to sqlite3_rollback_hook()
4680: ** for the same database connection is overridden.
4681: ** ^The pArg argument is passed through to the callback.
4682: ** ^If the callback on a commit hook function returns non-zero,
4683: ** then the commit is converted into a rollback.
4684: **
4685: ** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
4686: ** return the P argument from the previous call of the same function
4687: ** on the same [database connection] D, or NULL for
4688: ** the first call for each function on D.
4689: **
4690: ** The commit and rollback hook callbacks are not reentrant.
4691: ** The callback implementation must not do anything that will modify
4692: ** the database connection that invoked the callback. Any actions
4693: ** to modify the database connection must be deferred until after the
4694: ** completion of the [sqlite3_step()] call that triggered the commit
4695: ** or rollback hook in the first place.
4696: ** Note that running any other SQL statements, including SELECT statements,
4697: ** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
4698: ** the database connections for the meaning of "modify" in this paragraph.
4699: **
4700: ** ^Registering a NULL function disables the callback.
4701: **
4702: ** ^When the commit hook callback routine returns zero, the [COMMIT]
4703: ** operation is allowed to continue normally. ^If the commit hook
4704: ** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
4705: ** ^The rollback hook is invoked on a rollback that results from a commit
4706: ** hook returning non-zero, just as it would be with any other rollback.
4707: **
4708: ** ^For the purposes of this API, a transaction is said to have been
4709: ** rolled back if an explicit "ROLLBACK" statement is executed, or
4710: ** an error or constraint causes an implicit rollback to occur.
4711: ** ^The rollback callback is not invoked if a transaction is
4712: ** automatically rolled back because the database connection is closed.
4713: **
4714: ** See also the [sqlite3_update_hook()] interface.
4715: */
4716: SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
4717: SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
4718:
4719: /*
4720: ** CAPI3REF: Data Change Notification Callbacks
4721: **
4722: ** ^The sqlite3_update_hook() interface registers a callback function
4723: ** with the [database connection] identified by the first argument
4724: ** to be invoked whenever a row is updated, inserted or deleted.
4725: ** ^Any callback set by a previous call to this function
4726: ** for the same database connection is overridden.
4727: **
4728: ** ^The second argument is a pointer to the function to invoke when a
4729: ** row is updated, inserted or deleted.
4730: ** ^The first argument to the callback is a copy of the third argument
4731: ** to sqlite3_update_hook().
4732: ** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
4733: ** or [SQLITE_UPDATE], depending on the operation that caused the callback
4734: ** to be invoked.
4735: ** ^The third and fourth arguments to the callback contain pointers to the
4736: ** database and table name containing the affected row.
4737: ** ^The final callback parameter is the [rowid] of the row.
4738: ** ^In the case of an update, this is the [rowid] after the update takes place.
4739: **
4740: ** ^(The update hook is not invoked when internal system tables are
4741: ** modified (i.e. sqlite_master and sqlite_sequence).)^
4742: **
4743: ** ^In the current implementation, the update hook
4744: ** is not invoked when duplication rows are deleted because of an
4745: ** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook
4746: ** invoked when rows are deleted using the [truncate optimization].
4747: ** The exceptions defined in this paragraph might change in a future
4748: ** release of SQLite.
4749: **
4750: ** The update hook implementation must not do anything that will modify
4751: ** the database connection that invoked the update hook. Any actions
4752: ** to modify the database connection must be deferred until after the
4753: ** completion of the [sqlite3_step()] call that triggered the update hook.
4754: ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
4755: ** database connections for the meaning of "modify" in this paragraph.
4756: **
4757: ** ^The sqlite3_update_hook(D,C,P) function
4758: ** returns the P argument from the previous call
4759: ** on the same [database connection] D, or NULL for
4760: ** the first call on D.
4761: **
4762: ** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()]
4763: ** interfaces.
4764: */
4765: SQLITE_API void *sqlite3_update_hook(
4766: sqlite3*,
4767: void(*)(void *,int ,char const *,char const *,sqlite3_int64),
4768: void*
4769: );
4770:
4771: /*
4772: ** CAPI3REF: Enable Or Disable Shared Pager Cache
4773: **
4774: ** ^(This routine enables or disables the sharing of the database cache
4775: ** and schema data structures between [database connection | connections]
4776: ** to the same database. Sharing is enabled if the argument is true
4777: ** and disabled if the argument is false.)^
4778: **
4779: ** ^Cache sharing is enabled and disabled for an entire process.
4780: ** This is a change as of SQLite version 3.5.0. In prior versions of SQLite,
4781: ** sharing was enabled or disabled for each thread separately.
4782: **
4783: ** ^(The cache sharing mode set by this interface effects all subsequent
4784: ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
4785: ** Existing database connections continue use the sharing mode
4786: ** that was in effect at the time they were opened.)^
4787: **
4788: ** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
4789: ** successfully. An [error code] is returned otherwise.)^
4790: **
4791: ** ^Shared cache is disabled by default. But this might change in
4792: ** future releases of SQLite. Applications that care about shared
4793: ** cache setting should set it explicitly.
4794: **
1.3 ! misho 4795: ** This interface is threadsafe on processors where writing a
! 4796: ** 32-bit integer is atomic.
! 4797: **
1.2 misho 4798: ** See Also: [SQLite Shared-Cache Mode]
4799: */
4800: SQLITE_API int sqlite3_enable_shared_cache(int);
4801:
4802: /*
4803: ** CAPI3REF: Attempt To Free Heap Memory
4804: **
4805: ** ^The sqlite3_release_memory() interface attempts to free N bytes
4806: ** of heap memory by deallocating non-essential memory allocations
4807: ** held by the database library. Memory used to cache database
4808: ** pages to improve performance is an example of non-essential memory.
4809: ** ^sqlite3_release_memory() returns the number of bytes actually freed,
4810: ** which might be more or less than the amount requested.
4811: ** ^The sqlite3_release_memory() routine is a no-op returning zero
4812: ** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
4813: **
4814: ** See also: [sqlite3_db_release_memory()]
4815: */
4816: SQLITE_API int sqlite3_release_memory(int);
4817:
4818: /*
4819: ** CAPI3REF: Free Memory Used By A Database Connection
4820: **
4821: ** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap
4822: ** memory as possible from database connection D. Unlike the
4823: ** [sqlite3_release_memory()] interface, this interface is effect even
4824: ** when then [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
4825: ** omitted.
4826: **
4827: ** See also: [sqlite3_release_memory()]
4828: */
4829: SQLITE_API int sqlite3_db_release_memory(sqlite3*);
4830:
4831: /*
4832: ** CAPI3REF: Impose A Limit On Heap Size
4833: **
4834: ** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
4835: ** soft limit on the amount of heap memory that may be allocated by SQLite.
4836: ** ^SQLite strives to keep heap memory utilization below the soft heap
4837: ** limit by reducing the number of pages held in the page cache
4838: ** as heap memory usages approaches the limit.
4839: ** ^The soft heap limit is "soft" because even though SQLite strives to stay
4840: ** below the limit, it will exceed the limit rather than generate
4841: ** an [SQLITE_NOMEM] error. In other words, the soft heap limit
4842: ** is advisory only.
4843: **
4844: ** ^The return value from sqlite3_soft_heap_limit64() is the size of
4845: ** the soft heap limit prior to the call, or negative in the case of an
4846: ** error. ^If the argument N is negative
4847: ** then no change is made to the soft heap limit. Hence, the current
4848: ** size of the soft heap limit can be determined by invoking
4849: ** sqlite3_soft_heap_limit64() with a negative argument.
4850: **
4851: ** ^If the argument N is zero then the soft heap limit is disabled.
4852: **
4853: ** ^(The soft heap limit is not enforced in the current implementation
4854: ** if one or more of following conditions are true:
4855: **
4856: ** <ul>
4857: ** <li> The soft heap limit is set to zero.
4858: ** <li> Memory accounting is disabled using a combination of the
4859: ** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
4860: ** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
4861: ** <li> An alternative page cache implementation is specified using
4862: ** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
4863: ** <li> The page cache allocates from its own memory pool supplied
4864: ** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
4865: ** from the heap.
4866: ** </ul>)^
4867: **
4868: ** Beginning with SQLite version 3.7.3, the soft heap limit is enforced
4869: ** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT]
4870: ** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT],
4871: ** the soft heap limit is enforced on every memory allocation. Without
4872: ** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced
4873: ** when memory is allocated by the page cache. Testing suggests that because
4874: ** the page cache is the predominate memory user in SQLite, most
4875: ** applications will achieve adequate soft heap limit enforcement without
4876: ** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT].
4877: **
4878: ** The circumstances under which SQLite will enforce the soft heap limit may
4879: ** changes in future releases of SQLite.
4880: */
4881: SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);
4882:
4883: /*
4884: ** CAPI3REF: Deprecated Soft Heap Limit Interface
4885: ** DEPRECATED
4886: **
4887: ** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
4888: ** interface. This routine is provided for historical compatibility
4889: ** only. All new applications should use the
4890: ** [sqlite3_soft_heap_limit64()] interface rather than this one.
4891: */
4892: SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N);
4893:
4894:
4895: /*
4896: ** CAPI3REF: Extract Metadata About A Column Of A Table
4897: **
4898: ** ^This routine returns metadata about a specific column of a specific
4899: ** database table accessible using the [database connection] handle
4900: ** passed as the first function argument.
4901: **
4902: ** ^The column is identified by the second, third and fourth parameters to
4903: ** this function. ^The second parameter is either the name of the database
4904: ** (i.e. "main", "temp", or an attached database) containing the specified
4905: ** table or NULL. ^If it is NULL, then all attached databases are searched
4906: ** for the table using the same algorithm used by the database engine to
4907: ** resolve unqualified table references.
4908: **
4909: ** ^The third and fourth parameters to this function are the table and column
4910: ** name of the desired column, respectively. Neither of these parameters
4911: ** may be NULL.
4912: **
4913: ** ^Metadata is returned by writing to the memory locations passed as the 5th
4914: ** and subsequent parameters to this function. ^Any of these arguments may be
4915: ** NULL, in which case the corresponding element of metadata is omitted.
4916: **
4917: ** ^(<blockquote>
4918: ** <table border="1">
4919: ** <tr><th> Parameter <th> Output<br>Type <th> Description
4920: **
4921: ** <tr><td> 5th <td> const char* <td> Data type
4922: ** <tr><td> 6th <td> const char* <td> Name of default collation sequence
4923: ** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint
4924: ** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY
4925: ** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT]
4926: ** </table>
4927: ** </blockquote>)^
4928: **
4929: ** ^The memory pointed to by the character pointers returned for the
4930: ** declaration type and collation sequence is valid only until the next
4931: ** call to any SQLite API function.
4932: **
4933: ** ^If the specified table is actually a view, an [error code] is returned.
4934: **
4935: ** ^If the specified column is "rowid", "oid" or "_rowid_" and an
4936: ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
4937: ** parameters are set for the explicitly declared column. ^(If there is no
4938: ** explicitly declared [INTEGER PRIMARY KEY] column, then the output
4939: ** parameters are set as follows:
4940: **
4941: ** <pre>
4942: ** data type: "INTEGER"
4943: ** collation sequence: "BINARY"
4944: ** not null: 0
4945: ** primary key: 1
4946: ** auto increment: 0
4947: ** </pre>)^
4948: **
4949: ** ^(This function may load one or more schemas from database files. If an
4950: ** error occurs during this process, or if the requested table or column
4951: ** cannot be found, an [error code] is returned and an error message left
4952: ** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^
4953: **
4954: ** ^This API is only available if the library was compiled with the
4955: ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined.
4956: */
4957: SQLITE_API int sqlite3_table_column_metadata(
4958: sqlite3 *db, /* Connection handle */
4959: const char *zDbName, /* Database name or NULL */
4960: const char *zTableName, /* Table name */
4961: const char *zColumnName, /* Column name */
4962: char const **pzDataType, /* OUTPUT: Declared data type */
4963: char const **pzCollSeq, /* OUTPUT: Collation sequence name */
4964: int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */
4965: int *pPrimaryKey, /* OUTPUT: True if column part of PK */
4966: int *pAutoinc /* OUTPUT: True if column is auto-increment */
4967: );
4968:
4969: /*
4970: ** CAPI3REF: Load An Extension
4971: **
4972: ** ^This interface loads an SQLite extension library from the named file.
4973: **
4974: ** ^The sqlite3_load_extension() interface attempts to load an
4975: ** SQLite extension library contained in the file zFile.
4976: **
4977: ** ^The entry point is zProc.
4978: ** ^zProc may be 0, in which case the name of the entry point
4979: ** defaults to "sqlite3_extension_init".
4980: ** ^The sqlite3_load_extension() interface returns
4981: ** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
4982: ** ^If an error occurs and pzErrMsg is not 0, then the
4983: ** [sqlite3_load_extension()] interface shall attempt to
4984: ** fill *pzErrMsg with error message text stored in memory
4985: ** obtained from [sqlite3_malloc()]. The calling function
4986: ** should free this memory by calling [sqlite3_free()].
4987: **
4988: ** ^Extension loading must be enabled using
4989: ** [sqlite3_enable_load_extension()] prior to calling this API,
4990: ** otherwise an error will be returned.
4991: **
4992: ** See also the [load_extension() SQL function].
4993: */
4994: SQLITE_API int sqlite3_load_extension(
4995: sqlite3 *db, /* Load the extension into this database connection */
4996: const char *zFile, /* Name of the shared library containing extension */
4997: const char *zProc, /* Entry point. Derived from zFile if 0 */
4998: char **pzErrMsg /* Put error message here if not 0 */
4999: );
5000:
5001: /*
5002: ** CAPI3REF: Enable Or Disable Extension Loading
5003: **
5004: ** ^So as not to open security holes in older applications that are
5005: ** unprepared to deal with extension loading, and as a means of disabling
5006: ** extension loading while evaluating user-entered SQL, the following API
5007: ** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
5008: **
5009: ** ^Extension loading is off by default. See ticket #1863.
5010: ** ^Call the sqlite3_enable_load_extension() routine with onoff==1
5011: ** to turn extension loading on and call it with onoff==0 to turn
5012: ** it back off again.
5013: */
5014: SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
5015:
5016: /*
5017: ** CAPI3REF: Automatically Load Statically Linked Extensions
5018: **
5019: ** ^This interface causes the xEntryPoint() function to be invoked for
5020: ** each new [database connection] that is created. The idea here is that
5021: ** xEntryPoint() is the entry point for a statically linked SQLite extension
5022: ** that is to be automatically loaded into all new database connections.
5023: **
5024: ** ^(Even though the function prototype shows that xEntryPoint() takes
5025: ** no arguments and returns void, SQLite invokes xEntryPoint() with three
5026: ** arguments and expects and integer result as if the signature of the
5027: ** entry point where as follows:
5028: **
5029: ** <blockquote><pre>
5030: ** int xEntryPoint(
5031: ** sqlite3 *db,
5032: ** const char **pzErrMsg,
5033: ** const struct sqlite3_api_routines *pThunk
5034: ** );
5035: ** </pre></blockquote>)^
5036: **
5037: ** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
5038: ** point to an appropriate error message (obtained from [sqlite3_mprintf()])
5039: ** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg
5040: ** is NULL before calling the xEntryPoint(). ^SQLite will invoke
5041: ** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any
5042: ** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
5043: ** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
5044: **
5045: ** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
5046: ** on the list of automatic extensions is a harmless no-op. ^No entry point
5047: ** will be called more than once for each database connection that is opened.
5048: **
5049: ** See also: [sqlite3_reset_auto_extension()].
5050: */
5051: SQLITE_API int sqlite3_auto_extension(void (*xEntryPoint)(void));
5052:
5053: /*
5054: ** CAPI3REF: Reset Automatic Extension Loading
5055: **
5056: ** ^This interface disables all automatic extensions previously
5057: ** registered using [sqlite3_auto_extension()].
5058: */
5059: SQLITE_API void sqlite3_reset_auto_extension(void);
5060:
5061: /*
5062: ** The interface to the virtual-table mechanism is currently considered
5063: ** to be experimental. The interface might change in incompatible ways.
5064: ** If this is a problem for you, do not use the interface at this time.
5065: **
5066: ** When the virtual-table mechanism stabilizes, we will declare the
5067: ** interface fixed, support it indefinitely, and remove this comment.
5068: */
5069:
5070: /*
5071: ** Structures used by the virtual table interface
5072: */
5073: typedef struct sqlite3_vtab sqlite3_vtab;
5074: typedef struct sqlite3_index_info sqlite3_index_info;
5075: typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
5076: typedef struct sqlite3_module sqlite3_module;
5077:
5078: /*
5079: ** CAPI3REF: Virtual Table Object
5080: ** KEYWORDS: sqlite3_module {virtual table module}
5081: **
5082: ** This structure, sometimes called a "virtual table module",
5083: ** defines the implementation of a [virtual tables].
5084: ** This structure consists mostly of methods for the module.
5085: **
5086: ** ^A virtual table module is created by filling in a persistent
5087: ** instance of this structure and passing a pointer to that instance
5088: ** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
5089: ** ^The registration remains valid until it is replaced by a different
5090: ** module or until the [database connection] closes. The content
5091: ** of this structure must not change while it is registered with
5092: ** any database connection.
5093: */
5094: struct sqlite3_module {
5095: int iVersion;
5096: int (*xCreate)(sqlite3*, void *pAux,
5097: int argc, const char *const*argv,
5098: sqlite3_vtab **ppVTab, char**);
5099: int (*xConnect)(sqlite3*, void *pAux,
5100: int argc, const char *const*argv,
5101: sqlite3_vtab **ppVTab, char**);
5102: int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
5103: int (*xDisconnect)(sqlite3_vtab *pVTab);
5104: int (*xDestroy)(sqlite3_vtab *pVTab);
5105: int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
5106: int (*xClose)(sqlite3_vtab_cursor*);
5107: int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
5108: int argc, sqlite3_value **argv);
5109: int (*xNext)(sqlite3_vtab_cursor*);
5110: int (*xEof)(sqlite3_vtab_cursor*);
5111: int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
5112: int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
5113: int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
5114: int (*xBegin)(sqlite3_vtab *pVTab);
5115: int (*xSync)(sqlite3_vtab *pVTab);
5116: int (*xCommit)(sqlite3_vtab *pVTab);
5117: int (*xRollback)(sqlite3_vtab *pVTab);
5118: int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
5119: void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
5120: void **ppArg);
5121: int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
5122: /* The methods above are in version 1 of the sqlite_module object. Those
5123: ** below are for version 2 and greater. */
5124: int (*xSavepoint)(sqlite3_vtab *pVTab, int);
5125: int (*xRelease)(sqlite3_vtab *pVTab, int);
5126: int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
5127: };
5128:
5129: /*
5130: ** CAPI3REF: Virtual Table Indexing Information
5131: ** KEYWORDS: sqlite3_index_info
5132: **
5133: ** The sqlite3_index_info structure and its substructures is used as part
5134: ** of the [virtual table] interface to
5135: ** pass information into and receive the reply from the [xBestIndex]
5136: ** method of a [virtual table module]. The fields under **Inputs** are the
5137: ** inputs to xBestIndex and are read-only. xBestIndex inserts its
5138: ** results into the **Outputs** fields.
5139: **
5140: ** ^(The aConstraint[] array records WHERE clause constraints of the form:
5141: **
5142: ** <blockquote>column OP expr</blockquote>
5143: **
5144: ** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is
5145: ** stored in aConstraint[].op using one of the
5146: ** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
5147: ** ^(The index of the column is stored in
5148: ** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the
5149: ** expr on the right-hand side can be evaluated (and thus the constraint
5150: ** is usable) and false if it cannot.)^
5151: **
5152: ** ^The optimizer automatically inverts terms of the form "expr OP column"
5153: ** and makes other simplifications to the WHERE clause in an attempt to
5154: ** get as many WHERE clause terms into the form shown above as possible.
5155: ** ^The aConstraint[] array only reports WHERE clause terms that are
5156: ** relevant to the particular virtual table being queried.
5157: **
5158: ** ^Information about the ORDER BY clause is stored in aOrderBy[].
5159: ** ^Each term of aOrderBy records a column of the ORDER BY clause.
5160: **
5161: ** The [xBestIndex] method must fill aConstraintUsage[] with information
5162: ** about what parameters to pass to xFilter. ^If argvIndex>0 then
5163: ** the right-hand side of the corresponding aConstraint[] is evaluated
5164: ** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit
5165: ** is true, then the constraint is assumed to be fully handled by the
5166: ** virtual table and is not checked again by SQLite.)^
5167: **
5168: ** ^The idxNum and idxPtr values are recorded and passed into the
5169: ** [xFilter] method.
5170: ** ^[sqlite3_free()] is used to free idxPtr if and only if
5171: ** needToFreeIdxPtr is true.
5172: **
5173: ** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
5174: ** the correct order to satisfy the ORDER BY clause so that no separate
5175: ** sorting step is required.
5176: **
5177: ** ^The estimatedCost value is an estimate of the cost of doing the
5178: ** particular lookup. A full scan of a table with N entries should have
5179: ** a cost of N. A binary search of a table of N entries should have a
5180: ** cost of approximately log(N).
5181: */
5182: struct sqlite3_index_info {
5183: /* Inputs */
5184: int nConstraint; /* Number of entries in aConstraint */
5185: struct sqlite3_index_constraint {
5186: int iColumn; /* Column on left-hand side of constraint */
5187: unsigned char op; /* Constraint operator */
5188: unsigned char usable; /* True if this constraint is usable */
5189: int iTermOffset; /* Used internally - xBestIndex should ignore */
5190: } *aConstraint; /* Table of WHERE clause constraints */
5191: int nOrderBy; /* Number of terms in the ORDER BY clause */
5192: struct sqlite3_index_orderby {
5193: int iColumn; /* Column number */
5194: unsigned char desc; /* True for DESC. False for ASC. */
5195: } *aOrderBy; /* The ORDER BY clause */
5196: /* Outputs */
5197: struct sqlite3_index_constraint_usage {
5198: int argvIndex; /* if >0, constraint is part of argv to xFilter */
5199: unsigned char omit; /* Do not code a test for this constraint */
5200: } *aConstraintUsage;
5201: int idxNum; /* Number used to identify the index */
5202: char *idxStr; /* String, possibly obtained from sqlite3_malloc */
5203: int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */
5204: int orderByConsumed; /* True if output is already ordered */
5205: double estimatedCost; /* Estimated cost of using this index */
5206: };
5207:
5208: /*
5209: ** CAPI3REF: Virtual Table Constraint Operator Codes
5210: **
5211: ** These macros defined the allowed values for the
5212: ** [sqlite3_index_info].aConstraint[].op field. Each value represents
5213: ** an operator that is part of a constraint term in the wHERE clause of
5214: ** a query that uses a [virtual table].
5215: */
5216: #define SQLITE_INDEX_CONSTRAINT_EQ 2
5217: #define SQLITE_INDEX_CONSTRAINT_GT 4
5218: #define SQLITE_INDEX_CONSTRAINT_LE 8
5219: #define SQLITE_INDEX_CONSTRAINT_LT 16
5220: #define SQLITE_INDEX_CONSTRAINT_GE 32
5221: #define SQLITE_INDEX_CONSTRAINT_MATCH 64
5222:
5223: /*
5224: ** CAPI3REF: Register A Virtual Table Implementation
5225: **
5226: ** ^These routines are used to register a new [virtual table module] name.
5227: ** ^Module names must be registered before
5228: ** creating a new [virtual table] using the module and before using a
5229: ** preexisting [virtual table] for the module.
5230: **
5231: ** ^The module name is registered on the [database connection] specified
5232: ** by the first parameter. ^The name of the module is given by the
5233: ** second parameter. ^The third parameter is a pointer to
5234: ** the implementation of the [virtual table module]. ^The fourth
5235: ** parameter is an arbitrary client data pointer that is passed through
5236: ** into the [xCreate] and [xConnect] methods of the virtual table module
5237: ** when a new virtual table is be being created or reinitialized.
5238: **
5239: ** ^The sqlite3_create_module_v2() interface has a fifth parameter which
5240: ** is a pointer to a destructor for the pClientData. ^SQLite will
5241: ** invoke the destructor function (if it is not NULL) when SQLite
5242: ** no longer needs the pClientData pointer. ^The destructor will also
5243: ** be invoked if the call to sqlite3_create_module_v2() fails.
5244: ** ^The sqlite3_create_module()
5245: ** interface is equivalent to sqlite3_create_module_v2() with a NULL
5246: ** destructor.
5247: */
5248: SQLITE_API int sqlite3_create_module(
5249: sqlite3 *db, /* SQLite connection to register module with */
5250: const char *zName, /* Name of the module */
5251: const sqlite3_module *p, /* Methods for the module */
5252: void *pClientData /* Client data for xCreate/xConnect */
5253: );
5254: SQLITE_API int sqlite3_create_module_v2(
5255: sqlite3 *db, /* SQLite connection to register module with */
5256: const char *zName, /* Name of the module */
5257: const sqlite3_module *p, /* Methods for the module */
5258: void *pClientData, /* Client data for xCreate/xConnect */
5259: void(*xDestroy)(void*) /* Module destructor function */
5260: );
5261:
5262: /*
5263: ** CAPI3REF: Virtual Table Instance Object
5264: ** KEYWORDS: sqlite3_vtab
5265: **
5266: ** Every [virtual table module] implementation uses a subclass
5267: ** of this object to describe a particular instance
5268: ** of the [virtual table]. Each subclass will
5269: ** be tailored to the specific needs of the module implementation.
5270: ** The purpose of this superclass is to define certain fields that are
5271: ** common to all module implementations.
5272: **
5273: ** ^Virtual tables methods can set an error message by assigning a
5274: ** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should
5275: ** take care that any prior string is freed by a call to [sqlite3_free()]
5276: ** prior to assigning a new string to zErrMsg. ^After the error message
5277: ** is delivered up to the client application, the string will be automatically
5278: ** freed by sqlite3_free() and the zErrMsg field will be zeroed.
5279: */
5280: struct sqlite3_vtab {
5281: const sqlite3_module *pModule; /* The module for this virtual table */
5282: int nRef; /* NO LONGER USED */
5283: char *zErrMsg; /* Error message from sqlite3_mprintf() */
5284: /* Virtual table implementations will typically add additional fields */
5285: };
5286:
5287: /*
5288: ** CAPI3REF: Virtual Table Cursor Object
5289: ** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
5290: **
5291: ** Every [virtual table module] implementation uses a subclass of the
5292: ** following structure to describe cursors that point into the
5293: ** [virtual table] and are used
5294: ** to loop through the virtual table. Cursors are created using the
5295: ** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
5296: ** by the [sqlite3_module.xClose | xClose] method. Cursors are used
5297: ** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
5298: ** of the module. Each module implementation will define
5299: ** the content of a cursor structure to suit its own needs.
5300: **
5301: ** This superclass exists in order to define fields of the cursor that
5302: ** are common to all implementations.
5303: */
5304: struct sqlite3_vtab_cursor {
5305: sqlite3_vtab *pVtab; /* Virtual table of this cursor */
5306: /* Virtual table implementations will typically add additional fields */
5307: };
5308:
5309: /*
5310: ** CAPI3REF: Declare The Schema Of A Virtual Table
5311: **
5312: ** ^The [xCreate] and [xConnect] methods of a
5313: ** [virtual table module] call this interface
5314: ** to declare the format (the names and datatypes of the columns) of
5315: ** the virtual tables they implement.
5316: */
5317: SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
5318:
5319: /*
5320: ** CAPI3REF: Overload A Function For A Virtual Table
5321: **
5322: ** ^(Virtual tables can provide alternative implementations of functions
5323: ** using the [xFindFunction] method of the [virtual table module].
5324: ** But global versions of those functions
5325: ** must exist in order to be overloaded.)^
5326: **
5327: ** ^(This API makes sure a global version of a function with a particular
5328: ** name and number of parameters exists. If no such function exists
5329: ** before this API is called, a new function is created.)^ ^The implementation
5330: ** of the new function always causes an exception to be thrown. So
5331: ** the new function is not good for anything by itself. Its only
5332: ** purpose is to be a placeholder function that can be overloaded
5333: ** by a [virtual table].
5334: */
5335: SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
5336:
5337: /*
5338: ** The interface to the virtual-table mechanism defined above (back up
5339: ** to a comment remarkably similar to this one) is currently considered
5340: ** to be experimental. The interface might change in incompatible ways.
5341: ** If this is a problem for you, do not use the interface at this time.
5342: **
5343: ** When the virtual-table mechanism stabilizes, we will declare the
5344: ** interface fixed, support it indefinitely, and remove this comment.
5345: */
5346:
5347: /*
5348: ** CAPI3REF: A Handle To An Open BLOB
5349: ** KEYWORDS: {BLOB handle} {BLOB handles}
5350: **
5351: ** An instance of this object represents an open BLOB on which
5352: ** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
5353: ** ^Objects of this type are created by [sqlite3_blob_open()]
5354: ** and destroyed by [sqlite3_blob_close()].
5355: ** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
5356: ** can be used to read or write small subsections of the BLOB.
5357: ** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
5358: */
5359: typedef struct sqlite3_blob sqlite3_blob;
5360:
5361: /*
5362: ** CAPI3REF: Open A BLOB For Incremental I/O
5363: **
5364: ** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
5365: ** in row iRow, column zColumn, table zTable in database zDb;
5366: ** in other words, the same BLOB that would be selected by:
5367: **
5368: ** <pre>
5369: ** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
5370: ** </pre>)^
5371: **
5372: ** ^If the flags parameter is non-zero, then the BLOB is opened for read
5373: ** and write access. ^If it is zero, the BLOB is opened for read access.
5374: ** ^It is not possible to open a column that is part of an index or primary
5375: ** key for writing. ^If [foreign key constraints] are enabled, it is
5376: ** not possible to open a column that is part of a [child key] for writing.
5377: **
5378: ** ^Note that the database name is not the filename that contains
5379: ** the database but rather the symbolic name of the database that
5380: ** appears after the AS keyword when the database is connected using [ATTACH].
5381: ** ^For the main database file, the database name is "main".
5382: ** ^For TEMP tables, the database name is "temp".
5383: **
5384: ** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written
5385: ** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set
5386: ** to be a null pointer.)^
5387: ** ^This function sets the [database connection] error code and message
5388: ** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related
5389: ** functions. ^Note that the *ppBlob variable is always initialized in a
5390: ** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob
5391: ** regardless of the success or failure of this routine.
5392: **
5393: ** ^(If the row that a BLOB handle points to is modified by an
5394: ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
5395: ** then the BLOB handle is marked as "expired".
5396: ** This is true if any column of the row is changed, even a column
5397: ** other than the one the BLOB handle is open on.)^
5398: ** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
5399: ** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
5400: ** ^(Changes written into a BLOB prior to the BLOB expiring are not
5401: ** rolled back by the expiration of the BLOB. Such changes will eventually
5402: ** commit if the transaction continues to completion.)^
5403: **
5404: ** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
5405: ** the opened blob. ^The size of a blob may not be changed by this
5406: ** interface. Use the [UPDATE] SQL command to change the size of a
5407: ** blob.
5408: **
5409: ** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
5410: ** and the built-in [zeroblob] SQL function can be used, if desired,
5411: ** to create an empty, zero-filled blob in which to read or write using
5412: ** this interface.
5413: **
5414: ** To avoid a resource leak, every open [BLOB handle] should eventually
5415: ** be released by a call to [sqlite3_blob_close()].
5416: */
5417: SQLITE_API int sqlite3_blob_open(
5418: sqlite3*,
5419: const char *zDb,
5420: const char *zTable,
5421: const char *zColumn,
5422: sqlite3_int64 iRow,
5423: int flags,
5424: sqlite3_blob **ppBlob
5425: );
5426:
5427: /*
5428: ** CAPI3REF: Move a BLOB Handle to a New Row
5429: **
5430: ** ^This function is used to move an existing blob handle so that it points
5431: ** to a different row of the same database table. ^The new row is identified
5432: ** by the rowid value passed as the second argument. Only the row can be
5433: ** changed. ^The database, table and column on which the blob handle is open
5434: ** remain the same. Moving an existing blob handle to a new row can be
5435: ** faster than closing the existing handle and opening a new one.
5436: **
5437: ** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
5438: ** it must exist and there must be either a blob or text value stored in
5439: ** the nominated column.)^ ^If the new row is not present in the table, or if
5440: ** it does not contain a blob or text value, or if another error occurs, an
5441: ** SQLite error code is returned and the blob handle is considered aborted.
5442: ** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
5443: ** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
5444: ** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
5445: ** always returns zero.
5446: **
5447: ** ^This function sets the database handle error code and message.
5448: */
5449: SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
5450:
5451: /*
5452: ** CAPI3REF: Close A BLOB Handle
5453: **
5454: ** ^Closes an open [BLOB handle].
5455: **
5456: ** ^Closing a BLOB shall cause the current transaction to commit
5457: ** if there are no other BLOBs, no pending prepared statements, and the
5458: ** database connection is in [autocommit mode].
5459: ** ^If any writes were made to the BLOB, they might be held in cache
5460: ** until the close operation if they will fit.
5461: **
5462: ** ^(Closing the BLOB often forces the changes
5463: ** out to disk and so if any I/O errors occur, they will likely occur
5464: ** at the time when the BLOB is closed. Any errors that occur during
5465: ** closing are reported as a non-zero return value.)^
5466: **
5467: ** ^(The BLOB is closed unconditionally. Even if this routine returns
5468: ** an error code, the BLOB is still closed.)^
5469: **
5470: ** ^Calling this routine with a null pointer (such as would be returned
5471: ** by a failed call to [sqlite3_blob_open()]) is a harmless no-op.
5472: */
5473: SQLITE_API int sqlite3_blob_close(sqlite3_blob *);
5474:
5475: /*
5476: ** CAPI3REF: Return The Size Of An Open BLOB
5477: **
5478: ** ^Returns the size in bytes of the BLOB accessible via the
5479: ** successfully opened [BLOB handle] in its only argument. ^The
5480: ** incremental blob I/O routines can only read or overwriting existing
5481: ** blob content; they cannot change the size of a blob.
5482: **
5483: ** This routine only works on a [BLOB handle] which has been created
5484: ** by a prior successful call to [sqlite3_blob_open()] and which has not
5485: ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
5486: ** to this routine results in undefined and probably undesirable behavior.
5487: */
5488: SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *);
5489:
5490: /*
5491: ** CAPI3REF: Read Data From A BLOB Incrementally
5492: **
5493: ** ^(This function is used to read data from an open [BLOB handle] into a
5494: ** caller-supplied buffer. N bytes of data are copied into buffer Z
5495: ** from the open BLOB, starting at offset iOffset.)^
5496: **
5497: ** ^If offset iOffset is less than N bytes from the end of the BLOB,
5498: ** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is
5499: ** less than zero, [SQLITE_ERROR] is returned and no data is read.
5500: ** ^The size of the blob (and hence the maximum value of N+iOffset)
5501: ** can be determined using the [sqlite3_blob_bytes()] interface.
5502: **
5503: ** ^An attempt to read from an expired [BLOB handle] fails with an
5504: ** error code of [SQLITE_ABORT].
5505: **
5506: ** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
5507: ** Otherwise, an [error code] or an [extended error code] is returned.)^
5508: **
5509: ** This routine only works on a [BLOB handle] which has been created
5510: ** by a prior successful call to [sqlite3_blob_open()] and which has not
5511: ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
5512: ** to this routine results in undefined and probably undesirable behavior.
5513: **
5514: ** See also: [sqlite3_blob_write()].
5515: */
5516: SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
5517:
5518: /*
5519: ** CAPI3REF: Write Data Into A BLOB Incrementally
5520: **
5521: ** ^This function is used to write data into an open [BLOB handle] from a
5522: ** caller-supplied buffer. ^N bytes of data are copied from the buffer Z
5523: ** into the open BLOB, starting at offset iOffset.
5524: **
5525: ** ^If the [BLOB handle] passed as the first argument was not opened for
5526: ** writing (the flags parameter to [sqlite3_blob_open()] was zero),
5527: ** this function returns [SQLITE_READONLY].
5528: **
5529: ** ^This function may only modify the contents of the BLOB; it is
5530: ** not possible to increase the size of a BLOB using this API.
5531: ** ^If offset iOffset is less than N bytes from the end of the BLOB,
5532: ** [SQLITE_ERROR] is returned and no data is written. ^If N is
5533: ** less than zero [SQLITE_ERROR] is returned and no data is written.
5534: ** The size of the BLOB (and hence the maximum value of N+iOffset)
5535: ** can be determined using the [sqlite3_blob_bytes()] interface.
5536: **
5537: ** ^An attempt to write to an expired [BLOB handle] fails with an
5538: ** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred
5539: ** before the [BLOB handle] expired are not rolled back by the
5540: ** expiration of the handle, though of course those changes might
5541: ** have been overwritten by the statement that expired the BLOB handle
5542: ** or by other independent statements.
5543: **
5544: ** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
5545: ** Otherwise, an [error code] or an [extended error code] is returned.)^
5546: **
5547: ** This routine only works on a [BLOB handle] which has been created
5548: ** by a prior successful call to [sqlite3_blob_open()] and which has not
5549: ** been closed by [sqlite3_blob_close()]. Passing any other pointer in
5550: ** to this routine results in undefined and probably undesirable behavior.
5551: **
5552: ** See also: [sqlite3_blob_read()].
5553: */
5554: SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
5555:
5556: /*
5557: ** CAPI3REF: Virtual File System Objects
5558: **
5559: ** A virtual filesystem (VFS) is an [sqlite3_vfs] object
5560: ** that SQLite uses to interact
5561: ** with the underlying operating system. Most SQLite builds come with a
5562: ** single default VFS that is appropriate for the host computer.
5563: ** New VFSes can be registered and existing VFSes can be unregistered.
5564: ** The following interfaces are provided.
5565: **
5566: ** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
5567: ** ^Names are case sensitive.
5568: ** ^Names are zero-terminated UTF-8 strings.
5569: ** ^If there is no match, a NULL pointer is returned.
5570: ** ^If zVfsName is NULL then the default VFS is returned.
5571: **
5572: ** ^New VFSes are registered with sqlite3_vfs_register().
5573: ** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
5574: ** ^The same VFS can be registered multiple times without injury.
5575: ** ^To make an existing VFS into the default VFS, register it again
5576: ** with the makeDflt flag set. If two different VFSes with the
5577: ** same name are registered, the behavior is undefined. If a
5578: ** VFS is registered with a name that is NULL or an empty string,
5579: ** then the behavior is undefined.
5580: **
5581: ** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
5582: ** ^(If the default VFS is unregistered, another VFS is chosen as
5583: ** the default. The choice for the new VFS is arbitrary.)^
5584: */
5585: SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
5586: SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
5587: SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*);
5588:
5589: /*
5590: ** CAPI3REF: Mutexes
5591: **
5592: ** The SQLite core uses these routines for thread
5593: ** synchronization. Though they are intended for internal
5594: ** use by SQLite, code that links against SQLite is
5595: ** permitted to use any of these routines.
5596: **
5597: ** The SQLite source code contains multiple implementations
5598: ** of these mutex routines. An appropriate implementation
5599: ** is selected automatically at compile-time. ^(The following
5600: ** implementations are available in the SQLite core:
5601: **
5602: ** <ul>
5603: ** <li> SQLITE_MUTEX_PTHREADS
5604: ** <li> SQLITE_MUTEX_W32
5605: ** <li> SQLITE_MUTEX_NOOP
5606: ** </ul>)^
5607: **
5608: ** ^The SQLITE_MUTEX_NOOP implementation is a set of routines
5609: ** that does no real locking and is appropriate for use in
1.3 ! misho 5610: ** a single-threaded application. ^The SQLITE_MUTEX_PTHREADS and
! 5611: ** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
! 5612: ** and Windows.
1.2 misho 5613: **
5614: ** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
5615: ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
5616: ** implementation is included with the library. In this case the
5617: ** application must supply a custom mutex implementation using the
5618: ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
5619: ** before calling sqlite3_initialize() or any other public sqlite3_
5620: ** function that calls sqlite3_initialize().)^
5621: **
5622: ** ^The sqlite3_mutex_alloc() routine allocates a new
5623: ** mutex and returns a pointer to it. ^If it returns NULL
5624: ** that means that a mutex could not be allocated. ^SQLite
5625: ** will unwind its stack and return an error. ^(The argument
5626: ** to sqlite3_mutex_alloc() is one of these integer constants:
5627: **
5628: ** <ul>
5629: ** <li> SQLITE_MUTEX_FAST
5630: ** <li> SQLITE_MUTEX_RECURSIVE
5631: ** <li> SQLITE_MUTEX_STATIC_MASTER
5632: ** <li> SQLITE_MUTEX_STATIC_MEM
5633: ** <li> SQLITE_MUTEX_STATIC_MEM2
5634: ** <li> SQLITE_MUTEX_STATIC_PRNG
5635: ** <li> SQLITE_MUTEX_STATIC_LRU
5636: ** <li> SQLITE_MUTEX_STATIC_LRU2
5637: ** </ul>)^
5638: **
5639: ** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
5640: ** cause sqlite3_mutex_alloc() to create
5641: ** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
5642: ** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
5643: ** The mutex implementation does not need to make a distinction
5644: ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
5645: ** not want to. ^SQLite will only request a recursive mutex in
5646: ** cases where it really needs one. ^If a faster non-recursive mutex
5647: ** implementation is available on the host platform, the mutex subsystem
5648: ** might return such a mutex in response to SQLITE_MUTEX_FAST.
5649: **
5650: ** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
5651: ** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
5652: ** a pointer to a static preexisting mutex. ^Six static mutexes are
5653: ** used by the current version of SQLite. Future versions of SQLite
5654: ** may add additional static mutexes. Static mutexes are for internal
5655: ** use by SQLite only. Applications that use SQLite mutexes should
5656: ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
5657: ** SQLITE_MUTEX_RECURSIVE.
5658: **
5659: ** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
5660: ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
5661: ** returns a different mutex on every call. ^But for the static
5662: ** mutex types, the same mutex is returned on every call that has
5663: ** the same type number.
5664: **
5665: ** ^The sqlite3_mutex_free() routine deallocates a previously
5666: ** allocated dynamic mutex. ^SQLite is careful to deallocate every
5667: ** dynamic mutex that it allocates. The dynamic mutexes must not be in
5668: ** use when they are deallocated. Attempting to deallocate a static
5669: ** mutex results in undefined behavior. ^SQLite never deallocates
5670: ** a static mutex.
5671: **
5672: ** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
5673: ** to enter a mutex. ^If another thread is already within the mutex,
5674: ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
5675: ** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
5676: ** upon successful entry. ^(Mutexes created using
5677: ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
5678: ** In such cases the,
5679: ** mutex must be exited an equal number of times before another thread
5680: ** can enter.)^ ^(If the same thread tries to enter any other
5681: ** kind of mutex more than once, the behavior is undefined.
5682: ** SQLite will never exhibit
5683: ** such behavior in its own use of mutexes.)^
5684: **
5685: ** ^(Some systems (for example, Windows 95) do not support the operation
5686: ** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try()
5687: ** will always return SQLITE_BUSY. The SQLite core only ever uses
5688: ** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^
5689: **
5690: ** ^The sqlite3_mutex_leave() routine exits a mutex that was
5691: ** previously entered by the same thread. ^(The behavior
5692: ** is undefined if the mutex is not currently entered by the
5693: ** calling thread or is not currently allocated. SQLite will
5694: ** never do either.)^
5695: **
5696: ** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
5697: ** sqlite3_mutex_leave() is a NULL pointer, then all three routines
5698: ** behave as no-ops.
5699: **
5700: ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
5701: */
5702: SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int);
5703: SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*);
5704: SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*);
5705: SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*);
5706: SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*);
5707:
5708: /*
5709: ** CAPI3REF: Mutex Methods Object
5710: **
5711: ** An instance of this structure defines the low-level routines
5712: ** used to allocate and use mutexes.
5713: **
5714: ** Usually, the default mutex implementations provided by SQLite are
5715: ** sufficient, however the user has the option of substituting a custom
5716: ** implementation for specialized deployments or systems for which SQLite
5717: ** does not provide a suitable implementation. In this case, the user
5718: ** creates and populates an instance of this structure to pass
5719: ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
5720: ** Additionally, an instance of this structure can be used as an
5721: ** output variable when querying the system for the current mutex
5722: ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
5723: **
5724: ** ^The xMutexInit method defined by this structure is invoked as
5725: ** part of system initialization by the sqlite3_initialize() function.
5726: ** ^The xMutexInit routine is called by SQLite exactly once for each
5727: ** effective call to [sqlite3_initialize()].
5728: **
5729: ** ^The xMutexEnd method defined by this structure is invoked as
5730: ** part of system shutdown by the sqlite3_shutdown() function. The
5731: ** implementation of this method is expected to release all outstanding
5732: ** resources obtained by the mutex methods implementation, especially
5733: ** those obtained by the xMutexInit method. ^The xMutexEnd()
5734: ** interface is invoked exactly once for each call to [sqlite3_shutdown()].
5735: **
5736: ** ^(The remaining seven methods defined by this structure (xMutexAlloc,
5737: ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
5738: ** xMutexNotheld) implement the following interfaces (respectively):
5739: **
5740: ** <ul>
5741: ** <li> [sqlite3_mutex_alloc()] </li>
5742: ** <li> [sqlite3_mutex_free()] </li>
5743: ** <li> [sqlite3_mutex_enter()] </li>
5744: ** <li> [sqlite3_mutex_try()] </li>
5745: ** <li> [sqlite3_mutex_leave()] </li>
5746: ** <li> [sqlite3_mutex_held()] </li>
5747: ** <li> [sqlite3_mutex_notheld()] </li>
5748: ** </ul>)^
5749: **
5750: ** The only difference is that the public sqlite3_XXX functions enumerated
5751: ** above silently ignore any invocations that pass a NULL pointer instead
5752: ** of a valid mutex handle. The implementations of the methods defined
5753: ** by this structure are not required to handle this case, the results
5754: ** of passing a NULL pointer instead of a valid mutex handle are undefined
5755: ** (i.e. it is acceptable to provide an implementation that segfaults if
5756: ** it is passed a NULL pointer).
5757: **
5758: ** The xMutexInit() method must be threadsafe. ^It must be harmless to
5759: ** invoke xMutexInit() multiple times within the same process and without
5760: ** intervening calls to xMutexEnd(). Second and subsequent calls to
5761: ** xMutexInit() must be no-ops.
5762: **
5763: ** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
5764: ** and its associates). ^Similarly, xMutexAlloc() must not use SQLite memory
5765: ** allocation for a static mutex. ^However xMutexAlloc() may use SQLite
5766: ** memory allocation for a fast or recursive mutex.
5767: **
5768: ** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
5769: ** called, but only if the prior call to xMutexInit returned SQLITE_OK.
5770: ** If xMutexInit fails in any way, it is expected to clean up after itself
5771: ** prior to returning.
5772: */
5773: typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
5774: struct sqlite3_mutex_methods {
5775: int (*xMutexInit)(void);
5776: int (*xMutexEnd)(void);
5777: sqlite3_mutex *(*xMutexAlloc)(int);
5778: void (*xMutexFree)(sqlite3_mutex *);
5779: void (*xMutexEnter)(sqlite3_mutex *);
5780: int (*xMutexTry)(sqlite3_mutex *);
5781: void (*xMutexLeave)(sqlite3_mutex *);
5782: int (*xMutexHeld)(sqlite3_mutex *);
5783: int (*xMutexNotheld)(sqlite3_mutex *);
5784: };
5785:
5786: /*
5787: ** CAPI3REF: Mutex Verification Routines
5788: **
5789: ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
5790: ** are intended for use inside assert() statements. ^The SQLite core
5791: ** never uses these routines except inside an assert() and applications
5792: ** are advised to follow the lead of the core. ^The SQLite core only
5793: ** provides implementations for these routines when it is compiled
5794: ** with the SQLITE_DEBUG flag. ^External mutex implementations
5795: ** are only required to provide these routines if SQLITE_DEBUG is
5796: ** defined and if NDEBUG is not defined.
5797: **
5798: ** ^These routines should return true if the mutex in their argument
5799: ** is held or not held, respectively, by the calling thread.
5800: **
5801: ** ^The implementation is not required to provide versions of these
5802: ** routines that actually work. If the implementation does not provide working
5803: ** versions of these routines, it should at least provide stubs that always
5804: ** return true so that one does not get spurious assertion failures.
5805: **
5806: ** ^If the argument to sqlite3_mutex_held() is a NULL pointer then
5807: ** the routine should return 1. This seems counter-intuitive since
5808: ** clearly the mutex cannot be held if it does not exist. But
5809: ** the reason the mutex does not exist is because the build is not
5810: ** using mutexes. And we do not want the assert() containing the
5811: ** call to sqlite3_mutex_held() to fail, so a non-zero return is
5812: ** the appropriate thing to do. ^The sqlite3_mutex_notheld()
5813: ** interface should also return 1 when given a NULL pointer.
5814: */
5815: #ifndef NDEBUG
5816: SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*);
5817: SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*);
5818: #endif
5819:
5820: /*
5821: ** CAPI3REF: Mutex Types
5822: **
5823: ** The [sqlite3_mutex_alloc()] interface takes a single argument
5824: ** which is one of these integer constants.
5825: **
5826: ** The set of static mutexes may change from one SQLite release to the
5827: ** next. Applications that override the built-in mutex logic must be
5828: ** prepared to accommodate additional static mutexes.
5829: */
5830: #define SQLITE_MUTEX_FAST 0
5831: #define SQLITE_MUTEX_RECURSIVE 1
5832: #define SQLITE_MUTEX_STATIC_MASTER 2
5833: #define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */
5834: #define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */
5835: #define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */
5836: #define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */
5837: #define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */
5838: #define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */
5839: #define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */
5840:
5841: /*
5842: ** CAPI3REF: Retrieve the mutex for a database connection
5843: **
5844: ** ^This interface returns a pointer the [sqlite3_mutex] object that
5845: ** serializes access to the [database connection] given in the argument
5846: ** when the [threading mode] is Serialized.
5847: ** ^If the [threading mode] is Single-thread or Multi-thread then this
5848: ** routine returns a NULL pointer.
5849: */
5850: SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
5851:
5852: /*
5853: ** CAPI3REF: Low-Level Control Of Database Files
5854: **
5855: ** ^The [sqlite3_file_control()] interface makes a direct call to the
5856: ** xFileControl method for the [sqlite3_io_methods] object associated
5857: ** with a particular database identified by the second argument. ^The
5858: ** name of the database is "main" for the main database or "temp" for the
5859: ** TEMP database, or the name that appears after the AS keyword for
5860: ** databases that are added using the [ATTACH] SQL command.
5861: ** ^A NULL pointer can be used in place of "main" to refer to the
5862: ** main database file.
5863: ** ^The third and fourth parameters to this routine
5864: ** are passed directly through to the second and third parameters of
5865: ** the xFileControl method. ^The return value of the xFileControl
5866: ** method becomes the return value of this routine.
5867: **
5868: ** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes
5869: ** a pointer to the underlying [sqlite3_file] object to be written into
5870: ** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER
5871: ** case is a short-circuit path which does not actually invoke the
5872: ** underlying sqlite3_io_methods.xFileControl method.
5873: **
5874: ** ^If the second parameter (zDbName) does not match the name of any
5875: ** open database file, then SQLITE_ERROR is returned. ^This error
5876: ** code is not remembered and will not be recalled by [sqlite3_errcode()]
5877: ** or [sqlite3_errmsg()]. The underlying xFileControl method might
5878: ** also return SQLITE_ERROR. There is no way to distinguish between
5879: ** an incorrect zDbName and an SQLITE_ERROR return from the underlying
5880: ** xFileControl method.
5881: **
5882: ** See also: [SQLITE_FCNTL_LOCKSTATE]
5883: */
5884: SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
5885:
5886: /*
5887: ** CAPI3REF: Testing Interface
5888: **
5889: ** ^The sqlite3_test_control() interface is used to read out internal
5890: ** state of SQLite and to inject faults into SQLite for testing
5891: ** purposes. ^The first parameter is an operation code that determines
5892: ** the number, meaning, and operation of all subsequent parameters.
5893: **
5894: ** This interface is not for use by applications. It exists solely
5895: ** for verifying the correct operation of the SQLite library. Depending
5896: ** on how the SQLite library is compiled, this interface might not exist.
5897: **
5898: ** The details of the operation codes, their meanings, the parameters
5899: ** they take, and what they do are all subject to change without notice.
5900: ** Unlike most of the SQLite API, this function is not guaranteed to
5901: ** operate consistently from one release to the next.
5902: */
5903: SQLITE_API int sqlite3_test_control(int op, ...);
5904:
5905: /*
5906: ** CAPI3REF: Testing Interface Operation Codes
5907: **
5908: ** These constants are the valid operation code parameters used
5909: ** as the first argument to [sqlite3_test_control()].
5910: **
5911: ** These parameters and their meanings are subject to change
5912: ** without notice. These values are for testing purposes only.
5913: ** Applications should not use any of these parameters or the
5914: ** [sqlite3_test_control()] interface.
5915: */
5916: #define SQLITE_TESTCTRL_FIRST 5
5917: #define SQLITE_TESTCTRL_PRNG_SAVE 5
5918: #define SQLITE_TESTCTRL_PRNG_RESTORE 6
5919: #define SQLITE_TESTCTRL_PRNG_RESET 7
5920: #define SQLITE_TESTCTRL_BITVEC_TEST 8
5921: #define SQLITE_TESTCTRL_FAULT_INSTALL 9
5922: #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10
5923: #define SQLITE_TESTCTRL_PENDING_BYTE 11
5924: #define SQLITE_TESTCTRL_ASSERT 12
5925: #define SQLITE_TESTCTRL_ALWAYS 13
5926: #define SQLITE_TESTCTRL_RESERVE 14
5927: #define SQLITE_TESTCTRL_OPTIMIZATIONS 15
5928: #define SQLITE_TESTCTRL_ISKEYWORD 16
5929: #define SQLITE_TESTCTRL_SCRATCHMALLOC 17
5930: #define SQLITE_TESTCTRL_LOCALTIME_FAULT 18
5931: #define SQLITE_TESTCTRL_EXPLAIN_STMT 19
5932: #define SQLITE_TESTCTRL_LAST 19
5933:
5934: /*
5935: ** CAPI3REF: SQLite Runtime Status
5936: **
5937: ** ^This interface is used to retrieve runtime status information
5938: ** about the performance of SQLite, and optionally to reset various
5939: ** highwater marks. ^The first argument is an integer code for
5940: ** the specific parameter to measure. ^(Recognized integer codes
5941: ** are of the form [status parameters | SQLITE_STATUS_...].)^
5942: ** ^The current value of the parameter is returned into *pCurrent.
5943: ** ^The highest recorded value is returned in *pHighwater. ^If the
5944: ** resetFlag is true, then the highest record value is reset after
5945: ** *pHighwater is written. ^(Some parameters do not record the highest
5946: ** value. For those parameters
5947: ** nothing is written into *pHighwater and the resetFlag is ignored.)^
5948: ** ^(Other parameters record only the highwater mark and not the current
5949: ** value. For these latter parameters nothing is written into *pCurrent.)^
5950: **
5951: ** ^The sqlite3_status() routine returns SQLITE_OK on success and a
5952: ** non-zero [error code] on failure.
5953: **
5954: ** This routine is threadsafe but is not atomic. This routine can be
5955: ** called while other threads are running the same or different SQLite
5956: ** interfaces. However the values returned in *pCurrent and
5957: ** *pHighwater reflect the status of SQLite at different points in time
5958: ** and it is possible that another thread might change the parameter
5959: ** in between the times when *pCurrent and *pHighwater are written.
5960: **
5961: ** See also: [sqlite3_db_status()]
5962: */
5963: SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
5964:
5965:
5966: /*
5967: ** CAPI3REF: Status Parameters
5968: ** KEYWORDS: {status parameters}
5969: **
5970: ** These integer constants designate various run-time status parameters
5971: ** that can be returned by [sqlite3_status()].
5972: **
5973: ** <dl>
5974: ** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
5975: ** <dd>This parameter is the current amount of memory checked out
5976: ** using [sqlite3_malloc()], either directly or indirectly. The
5977: ** figure includes calls made to [sqlite3_malloc()] by the application
5978: ** and internal memory usage by the SQLite library. Scratch memory
5979: ** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache
5980: ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
5981: ** this parameter. The amount returned is the sum of the allocation
5982: ** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
5983: **
5984: ** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
5985: ** <dd>This parameter records the largest memory allocation request
5986: ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
5987: ** internal equivalents). Only the value returned in the
5988: ** *pHighwater parameter to [sqlite3_status()] is of interest.
5989: ** The value written into the *pCurrent parameter is undefined.</dd>)^
5990: **
5991: ** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
5992: ** <dd>This parameter records the number of separate memory allocations
5993: ** currently checked out.</dd>)^
5994: **
5995: ** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
5996: ** <dd>This parameter returns the number of pages used out of the
5997: ** [pagecache memory allocator] that was configured using
5998: ** [SQLITE_CONFIG_PAGECACHE]. The
5999: ** value returned is in pages, not in bytes.</dd>)^
6000: **
6001: ** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]]
6002: ** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
6003: ** <dd>This parameter returns the number of bytes of page cache
6004: ** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
6005: ** buffer and where forced to overflow to [sqlite3_malloc()]. The
6006: ** returned value includes allocations that overflowed because they
6007: ** where too large (they were larger than the "sz" parameter to
6008: ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
6009: ** no space was left in the page cache.</dd>)^
6010: **
6011: ** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
6012: ** <dd>This parameter records the largest memory allocation request
6013: ** handed to [pagecache memory allocator]. Only the value returned in the
6014: ** *pHighwater parameter to [sqlite3_status()] is of interest.
6015: ** The value written into the *pCurrent parameter is undefined.</dd>)^
6016: **
6017: ** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt>
6018: ** <dd>This parameter returns the number of allocations used out of the
6019: ** [scratch memory allocator] configured using
6020: ** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not
6021: ** in bytes. Since a single thread may only have one scratch allocation
6022: ** outstanding at time, this parameter also reports the number of threads
6023: ** using scratch memory at the same time.</dd>)^
6024: **
6025: ** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
6026: ** <dd>This parameter returns the number of bytes of scratch memory
6027: ** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH]
6028: ** buffer and where forced to overflow to [sqlite3_malloc()]. The values
6029: ** returned include overflows because the requested allocation was too
6030: ** larger (that is, because the requested allocation was larger than the
6031: ** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer
6032: ** slots were available.
6033: ** </dd>)^
6034: **
6035: ** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
6036: ** <dd>This parameter records the largest memory allocation request
6037: ** handed to [scratch memory allocator]. Only the value returned in the
6038: ** *pHighwater parameter to [sqlite3_status()] is of interest.
6039: ** The value written into the *pCurrent parameter is undefined.</dd>)^
6040: **
6041: ** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
6042: ** <dd>This parameter records the deepest parser stack. It is only
6043: ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
6044: ** </dl>
6045: **
6046: ** New status parameters may be added from time to time.
6047: */
6048: #define SQLITE_STATUS_MEMORY_USED 0
6049: #define SQLITE_STATUS_PAGECACHE_USED 1
6050: #define SQLITE_STATUS_PAGECACHE_OVERFLOW 2
6051: #define SQLITE_STATUS_SCRATCH_USED 3
6052: #define SQLITE_STATUS_SCRATCH_OVERFLOW 4
6053: #define SQLITE_STATUS_MALLOC_SIZE 5
6054: #define SQLITE_STATUS_PARSER_STACK 6
6055: #define SQLITE_STATUS_PAGECACHE_SIZE 7
6056: #define SQLITE_STATUS_SCRATCH_SIZE 8
6057: #define SQLITE_STATUS_MALLOC_COUNT 9
6058:
6059: /*
6060: ** CAPI3REF: Database Connection Status
6061: **
6062: ** ^This interface is used to retrieve runtime status information
6063: ** about a single [database connection]. ^The first argument is the
6064: ** database connection object to be interrogated. ^The second argument
6065: ** is an integer constant, taken from the set of
6066: ** [SQLITE_DBSTATUS options], that
6067: ** determines the parameter to interrogate. The set of
6068: ** [SQLITE_DBSTATUS options] is likely
6069: ** to grow in future releases of SQLite.
6070: **
6071: ** ^The current value of the requested parameter is written into *pCur
6072: ** and the highest instantaneous value is written into *pHiwtr. ^If
6073: ** the resetFlg is true, then the highest instantaneous value is
6074: ** reset back down to the current value.
6075: **
6076: ** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
6077: ** non-zero [error code] on failure.
6078: **
6079: ** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
6080: */
6081: SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
6082:
6083: /*
6084: ** CAPI3REF: Status Parameters for database connections
6085: ** KEYWORDS: {SQLITE_DBSTATUS options}
6086: **
6087: ** These constants are the available integer "verbs" that can be passed as
6088: ** the second argument to the [sqlite3_db_status()] interface.
6089: **
6090: ** New verbs may be added in future releases of SQLite. Existing verbs
6091: ** might be discontinued. Applications should check the return code from
6092: ** [sqlite3_db_status()] to make sure that the call worked.
6093: ** The [sqlite3_db_status()] interface will return a non-zero error code
6094: ** if a discontinued or unsupported verb is invoked.
6095: **
6096: ** <dl>
6097: ** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
6098: ** <dd>This parameter returns the number of lookaside memory slots currently
6099: ** checked out.</dd>)^
6100: **
6101: ** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
6102: ** <dd>This parameter returns the number malloc attempts that were
6103: ** satisfied using lookaside memory. Only the high-water value is meaningful;
6104: ** the current value is always zero.)^
6105: **
6106: ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]]
6107: ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
6108: ** <dd>This parameter returns the number malloc attempts that might have
6109: ** been satisfied using lookaside memory but failed due to the amount of
6110: ** memory requested being larger than the lookaside slot size.
6111: ** Only the high-water value is meaningful;
6112: ** the current value is always zero.)^
6113: **
6114: ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]]
6115: ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
6116: ** <dd>This parameter returns the number malloc attempts that might have
6117: ** been satisfied using lookaside memory but failed due to all lookaside
6118: ** memory already being in use.
6119: ** Only the high-water value is meaningful;
6120: ** the current value is always zero.)^
6121: **
6122: ** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
6123: ** <dd>This parameter returns the approximate number of of bytes of heap
6124: ** memory used by all pager caches associated with the database connection.)^
6125: ** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
6126: **
6127: ** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
6128: ** <dd>This parameter returns the approximate number of of bytes of heap
6129: ** memory used to store the schema for all databases associated
6130: ** with the connection - main, temp, and any [ATTACH]-ed databases.)^
6131: ** ^The full amount of memory used by the schemas is reported, even if the
6132: ** schema memory is shared with other database connections due to
6133: ** [shared cache mode] being enabled.
6134: ** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
6135: **
6136: ** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
6137: ** <dd>This parameter returns the approximate number of of bytes of heap
6138: ** and lookaside memory used by all prepared statements associated with
6139: ** the database connection.)^
6140: ** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
6141: ** </dd>
6142: **
6143: ** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt>
6144: ** <dd>This parameter returns the number of pager cache hits that have
6145: ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT
6146: ** is always 0.
6147: ** </dd>
6148: **
6149: ** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt>
6150: ** <dd>This parameter returns the number of pager cache misses that have
6151: ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS
6152: ** is always 0.
6153: ** </dd>
1.3 ! misho 6154: **
! 6155: ** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt>
! 6156: ** <dd>This parameter returns the number of dirty cache entries that have
! 6157: ** been written to disk. Specifically, the number of pages written to the
! 6158: ** wal file in wal mode databases, or the number of pages written to the
! 6159: ** database file in rollback mode databases. Any pages written as part of
! 6160: ** transaction rollback or database recovery operations are not included.
! 6161: ** If an IO or other error occurs while writing a page to disk, the effect
! 6162: ** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The
! 6163: ** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0.
! 6164: ** </dd>
1.2 misho 6165: ** </dl>
6166: */
6167: #define SQLITE_DBSTATUS_LOOKASIDE_USED 0
6168: #define SQLITE_DBSTATUS_CACHE_USED 1
6169: #define SQLITE_DBSTATUS_SCHEMA_USED 2
6170: #define SQLITE_DBSTATUS_STMT_USED 3
6171: #define SQLITE_DBSTATUS_LOOKASIDE_HIT 4
6172: #define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5
6173: #define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6
6174: #define SQLITE_DBSTATUS_CACHE_HIT 7
6175: #define SQLITE_DBSTATUS_CACHE_MISS 8
1.3 ! misho 6176: #define SQLITE_DBSTATUS_CACHE_WRITE 9
! 6177: #define SQLITE_DBSTATUS_MAX 9 /* Largest defined DBSTATUS */
1.2 misho 6178:
6179:
6180: /*
6181: ** CAPI3REF: Prepared Statement Status
6182: **
6183: ** ^(Each prepared statement maintains various
6184: ** [SQLITE_STMTSTATUS counters] that measure the number
6185: ** of times it has performed specific operations.)^ These counters can
6186: ** be used to monitor the performance characteristics of the prepared
6187: ** statements. For example, if the number of table steps greatly exceeds
6188: ** the number of table searches or result rows, that would tend to indicate
6189: ** that the prepared statement is using a full table scan rather than
6190: ** an index.
6191: **
6192: ** ^(This interface is used to retrieve and reset counter values from
6193: ** a [prepared statement]. The first argument is the prepared statement
6194: ** object to be interrogated. The second argument
6195: ** is an integer code for a specific [SQLITE_STMTSTATUS counter]
6196: ** to be interrogated.)^
6197: ** ^The current value of the requested counter is returned.
6198: ** ^If the resetFlg is true, then the counter is reset to zero after this
6199: ** interface call returns.
6200: **
6201: ** See also: [sqlite3_status()] and [sqlite3_db_status()].
6202: */
6203: SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
6204:
6205: /*
6206: ** CAPI3REF: Status Parameters for prepared statements
6207: ** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters}
6208: **
6209: ** These preprocessor macros define integer codes that name counter
6210: ** values associated with the [sqlite3_stmt_status()] interface.
6211: ** The meanings of the various counters are as follows:
6212: **
6213: ** <dl>
6214: ** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
6215: ** <dd>^This is the number of times that SQLite has stepped forward in
6216: ** a table as part of a full table scan. Large numbers for this counter
6217: ** may indicate opportunities for performance improvement through
6218: ** careful use of indices.</dd>
6219: **
6220: ** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt>
6221: ** <dd>^This is the number of sort operations that have occurred.
6222: ** A non-zero value in this counter may indicate an opportunity to
6223: ** improvement performance through careful use of indices.</dd>
6224: **
6225: ** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
6226: ** <dd>^This is the number of rows inserted into transient indices that
6227: ** were created automatically in order to help joins run faster.
6228: ** A non-zero value in this counter may indicate an opportunity to
6229: ** improvement performance by adding permanent indices that do not
6230: ** need to be reinitialized each time the statement is run.</dd>
6231: ** </dl>
6232: */
6233: #define SQLITE_STMTSTATUS_FULLSCAN_STEP 1
6234: #define SQLITE_STMTSTATUS_SORT 2
6235: #define SQLITE_STMTSTATUS_AUTOINDEX 3
6236:
6237: /*
6238: ** CAPI3REF: Custom Page Cache Object
6239: **
6240: ** The sqlite3_pcache type is opaque. It is implemented by
6241: ** the pluggable module. The SQLite core has no knowledge of
6242: ** its size or internal structure and never deals with the
6243: ** sqlite3_pcache object except by holding and passing pointers
6244: ** to the object.
6245: **
6246: ** See [sqlite3_pcache_methods2] for additional information.
6247: */
6248: typedef struct sqlite3_pcache sqlite3_pcache;
6249:
6250: /*
6251: ** CAPI3REF: Custom Page Cache Object
6252: **
6253: ** The sqlite3_pcache_page object represents a single page in the
6254: ** page cache. The page cache will allocate instances of this
6255: ** object. Various methods of the page cache use pointers to instances
6256: ** of this object as parameters or as their return value.
6257: **
6258: ** See [sqlite3_pcache_methods2] for additional information.
6259: */
6260: typedef struct sqlite3_pcache_page sqlite3_pcache_page;
6261: struct sqlite3_pcache_page {
6262: void *pBuf; /* The content of the page */
6263: void *pExtra; /* Extra information associated with the page */
6264: };
6265:
6266: /*
6267: ** CAPI3REF: Application Defined Page Cache.
6268: ** KEYWORDS: {page cache}
6269: **
6270: ** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can
6271: ** register an alternative page cache implementation by passing in an
6272: ** instance of the sqlite3_pcache_methods2 structure.)^
6273: ** In many applications, most of the heap memory allocated by
6274: ** SQLite is used for the page cache.
6275: ** By implementing a
6276: ** custom page cache using this API, an application can better control
6277: ** the amount of memory consumed by SQLite, the way in which
6278: ** that memory is allocated and released, and the policies used to
6279: ** determine exactly which parts of a database file are cached and for
6280: ** how long.
6281: **
6282: ** The alternative page cache mechanism is an
6283: ** extreme measure that is only needed by the most demanding applications.
6284: ** The built-in page cache is recommended for most uses.
6285: **
6286: ** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an
6287: ** internal buffer by SQLite within the call to [sqlite3_config]. Hence
6288: ** the application may discard the parameter after the call to
6289: ** [sqlite3_config()] returns.)^
6290: **
6291: ** [[the xInit() page cache method]]
6292: ** ^(The xInit() method is called once for each effective
6293: ** call to [sqlite3_initialize()])^
6294: ** (usually only once during the lifetime of the process). ^(The xInit()
6295: ** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^
6296: ** The intent of the xInit() method is to set up global data structures
6297: ** required by the custom page cache implementation.
6298: ** ^(If the xInit() method is NULL, then the
6299: ** built-in default page cache is used instead of the application defined
6300: ** page cache.)^
6301: **
6302: ** [[the xShutdown() page cache method]]
6303: ** ^The xShutdown() method is called by [sqlite3_shutdown()].
6304: ** It can be used to clean up
6305: ** any outstanding resources before process shutdown, if required.
6306: ** ^The xShutdown() method may be NULL.
6307: **
6308: ** ^SQLite automatically serializes calls to the xInit method,
6309: ** so the xInit method need not be threadsafe. ^The
6310: ** xShutdown method is only called from [sqlite3_shutdown()] so it does
6311: ** not need to be threadsafe either. All other methods must be threadsafe
6312: ** in multithreaded applications.
6313: **
6314: ** ^SQLite will never invoke xInit() more than once without an intervening
6315: ** call to xShutdown().
6316: **
6317: ** [[the xCreate() page cache methods]]
6318: ** ^SQLite invokes the xCreate() method to construct a new cache instance.
6319: ** SQLite will typically create one cache instance for each open database file,
6320: ** though this is not guaranteed. ^The
6321: ** first parameter, szPage, is the size in bytes of the pages that must
6322: ** be allocated by the cache. ^szPage will always a power of two. ^The
6323: ** second parameter szExtra is a number of bytes of extra storage
6324: ** associated with each page cache entry. ^The szExtra parameter will
6325: ** a number less than 250. SQLite will use the
6326: ** extra szExtra bytes on each page to store metadata about the underlying
6327: ** database page on disk. The value passed into szExtra depends
6328: ** on the SQLite version, the target platform, and how SQLite was compiled.
6329: ** ^The third argument to xCreate(), bPurgeable, is true if the cache being
6330: ** created will be used to cache database pages of a file stored on disk, or
6331: ** false if it is used for an in-memory database. The cache implementation
6332: ** does not have to do anything special based with the value of bPurgeable;
6333: ** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will
6334: ** never invoke xUnpin() except to deliberately delete a page.
6335: ** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
6336: ** false will always have the "discard" flag set to true.
6337: ** ^Hence, a cache created with bPurgeable false will
6338: ** never contain any unpinned pages.
6339: **
6340: ** [[the xCachesize() page cache method]]
6341: ** ^(The xCachesize() method may be called at any time by SQLite to set the
6342: ** suggested maximum cache-size (number of pages stored by) the cache
6343: ** instance passed as the first argument. This is the value configured using
6344: ** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable
6345: ** parameter, the implementation is not required to do anything with this
6346: ** value; it is advisory only.
6347: **
6348: ** [[the xPagecount() page cache methods]]
6349: ** The xPagecount() method must return the number of pages currently
6350: ** stored in the cache, both pinned and unpinned.
6351: **
6352: ** [[the xFetch() page cache methods]]
6353: ** The xFetch() method locates a page in the cache and returns a pointer to
6354: ** an sqlite3_pcache_page object associated with that page, or a NULL pointer.
6355: ** The pBuf element of the returned sqlite3_pcache_page object will be a
6356: ** pointer to a buffer of szPage bytes used to store the content of a
6357: ** single database page. The pExtra element of sqlite3_pcache_page will be
6358: ** a pointer to the szExtra bytes of extra storage that SQLite has requested
6359: ** for each entry in the page cache.
6360: **
6361: ** The page to be fetched is determined by the key. ^The minimum key value
6362: ** is 1. After it has been retrieved using xFetch, the page is considered
6363: ** to be "pinned".
6364: **
6365: ** If the requested page is already in the page cache, then the page cache
6366: ** implementation must return a pointer to the page buffer with its content
6367: ** intact. If the requested page is not already in the cache, then the
6368: ** cache implementation should use the value of the createFlag
6369: ** parameter to help it determined what action to take:
6370: **
6371: ** <table border=1 width=85% align=center>
6372: ** <tr><th> createFlag <th> Behaviour when page is not already in cache
6373: ** <tr><td> 0 <td> Do not allocate a new page. Return NULL.
6374: ** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
6375: ** Otherwise return NULL.
6376: ** <tr><td> 2 <td> Make every effort to allocate a new page. Only return
6377: ** NULL if allocating a new page is effectively impossible.
6378: ** </table>
6379: **
6380: ** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite
6381: ** will only use a createFlag of 2 after a prior call with a createFlag of 1
6382: ** failed.)^ In between the to xFetch() calls, SQLite may
6383: ** attempt to unpin one or more cache pages by spilling the content of
6384: ** pinned pages to disk and synching the operating system disk cache.
6385: **
6386: ** [[the xUnpin() page cache method]]
6387: ** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
6388: ** as its second argument. If the third parameter, discard, is non-zero,
6389: ** then the page must be evicted from the cache.
6390: ** ^If the discard parameter is
6391: ** zero, then the page may be discarded or retained at the discretion of
6392: ** page cache implementation. ^The page cache implementation
6393: ** may choose to evict unpinned pages at any time.
6394: **
6395: ** The cache must not perform any reference counting. A single
6396: ** call to xUnpin() unpins the page regardless of the number of prior calls
6397: ** to xFetch().
6398: **
6399: ** [[the xRekey() page cache methods]]
6400: ** The xRekey() method is used to change the key value associated with the
6401: ** page passed as the second argument. If the cache
6402: ** previously contains an entry associated with newKey, it must be
6403: ** discarded. ^Any prior cache entry associated with newKey is guaranteed not
6404: ** to be pinned.
6405: **
6406: ** When SQLite calls the xTruncate() method, the cache must discard all
6407: ** existing cache entries with page numbers (keys) greater than or equal
6408: ** to the value of the iLimit parameter passed to xTruncate(). If any
6409: ** of these pages are pinned, they are implicitly unpinned, meaning that
6410: ** they can be safely discarded.
6411: **
6412: ** [[the xDestroy() page cache method]]
6413: ** ^The xDestroy() method is used to delete a cache allocated by xCreate().
6414: ** All resources associated with the specified cache should be freed. ^After
6415: ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
6416: ** handle invalid, and will not use it with any other sqlite3_pcache_methods2
6417: ** functions.
6418: **
6419: ** [[the xShrink() page cache method]]
6420: ** ^SQLite invokes the xShrink() method when it wants the page cache to
6421: ** free up as much of heap memory as possible. The page cache implementation
6422: ** is not obligated to free any memory, but well-behaved implementations should
6423: ** do their best.
6424: */
6425: typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
6426: struct sqlite3_pcache_methods2 {
6427: int iVersion;
6428: void *pArg;
6429: int (*xInit)(void*);
6430: void (*xShutdown)(void*);
6431: sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
6432: void (*xCachesize)(sqlite3_pcache*, int nCachesize);
6433: int (*xPagecount)(sqlite3_pcache*);
6434: sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
6435: void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
6436: void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*,
6437: unsigned oldKey, unsigned newKey);
6438: void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
6439: void (*xDestroy)(sqlite3_pcache*);
6440: void (*xShrink)(sqlite3_pcache*);
6441: };
6442:
6443: /*
6444: ** This is the obsolete pcache_methods object that has now been replaced
6445: ** by sqlite3_pcache_methods2. This object is not used by SQLite. It is
6446: ** retained in the header file for backwards compatibility only.
6447: */
6448: typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
6449: struct sqlite3_pcache_methods {
6450: void *pArg;
6451: int (*xInit)(void*);
6452: void (*xShutdown)(void*);
6453: sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
6454: void (*xCachesize)(sqlite3_pcache*, int nCachesize);
6455: int (*xPagecount)(sqlite3_pcache*);
6456: void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
6457: void (*xUnpin)(sqlite3_pcache*, void*, int discard);
6458: void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
6459: void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
6460: void (*xDestroy)(sqlite3_pcache*);
6461: };
6462:
6463:
6464: /*
6465: ** CAPI3REF: Online Backup Object
6466: **
6467: ** The sqlite3_backup object records state information about an ongoing
6468: ** online backup operation. ^The sqlite3_backup object is created by
6469: ** a call to [sqlite3_backup_init()] and is destroyed by a call to
6470: ** [sqlite3_backup_finish()].
6471: **
6472: ** See Also: [Using the SQLite Online Backup API]
6473: */
6474: typedef struct sqlite3_backup sqlite3_backup;
6475:
6476: /*
6477: ** CAPI3REF: Online Backup API.
6478: **
6479: ** The backup API copies the content of one database into another.
6480: ** It is useful either for creating backups of databases or
6481: ** for copying in-memory databases to or from persistent files.
6482: **
6483: ** See Also: [Using the SQLite Online Backup API]
6484: **
6485: ** ^SQLite holds a write transaction open on the destination database file
6486: ** for the duration of the backup operation.
6487: ** ^The source database is read-locked only while it is being read;
6488: ** it is not locked continuously for the entire backup operation.
6489: ** ^Thus, the backup may be performed on a live source database without
6490: ** preventing other database connections from
6491: ** reading or writing to the source database while the backup is underway.
6492: **
6493: ** ^(To perform a backup operation:
6494: ** <ol>
6495: ** <li><b>sqlite3_backup_init()</b> is called once to initialize the
6496: ** backup,
6497: ** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
6498: ** the data between the two databases, and finally
6499: ** <li><b>sqlite3_backup_finish()</b> is called to release all resources
6500: ** associated with the backup operation.
6501: ** </ol>)^
6502: ** There should be exactly one call to sqlite3_backup_finish() for each
6503: ** successful call to sqlite3_backup_init().
6504: **
6505: ** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
6506: **
6507: ** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
6508: ** [database connection] associated with the destination database
6509: ** and the database name, respectively.
6510: ** ^The database name is "main" for the main database, "temp" for the
6511: ** temporary database, or the name specified after the AS keyword in
6512: ** an [ATTACH] statement for an attached database.
6513: ** ^The S and M arguments passed to
6514: ** sqlite3_backup_init(D,N,S,M) identify the [database connection]
6515: ** and database name of the source database, respectively.
6516: ** ^The source and destination [database connections] (parameters S and D)
6517: ** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
6518: ** an error.
6519: **
6520: ** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
6521: ** returned and an error code and error message are stored in the
6522: ** destination [database connection] D.
6523: ** ^The error code and message for the failed call to sqlite3_backup_init()
6524: ** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
6525: ** [sqlite3_errmsg16()] functions.
6526: ** ^A successful call to sqlite3_backup_init() returns a pointer to an
6527: ** [sqlite3_backup] object.
6528: ** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
6529: ** sqlite3_backup_finish() functions to perform the specified backup
6530: ** operation.
6531: **
6532: ** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
6533: **
6534: ** ^Function sqlite3_backup_step(B,N) will copy up to N pages between
6535: ** the source and destination databases specified by [sqlite3_backup] object B.
6536: ** ^If N is negative, all remaining source pages are copied.
6537: ** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
6538: ** are still more pages to be copied, then the function returns [SQLITE_OK].
6539: ** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
6540: ** from source to destination, then it returns [SQLITE_DONE].
6541: ** ^If an error occurs while running sqlite3_backup_step(B,N),
6542: ** then an [error code] is returned. ^As well as [SQLITE_OK] and
6543: ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
6544: ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
6545: ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
6546: **
6547: ** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
6548: ** <ol>
6549: ** <li> the destination database was opened read-only, or
6550: ** <li> the destination database is using write-ahead-log journaling
6551: ** and the destination and source page sizes differ, or
6552: ** <li> the destination database is an in-memory database and the
6553: ** destination and source page sizes differ.
6554: ** </ol>)^
6555: **
6556: ** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
6557: ** the [sqlite3_busy_handler | busy-handler function]
6558: ** is invoked (if one is specified). ^If the
6559: ** busy-handler returns non-zero before the lock is available, then
6560: ** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
6561: ** sqlite3_backup_step() can be retried later. ^If the source
6562: ** [database connection]
6563: ** is being used to write to the source database when sqlite3_backup_step()
6564: ** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
6565: ** case the call to sqlite3_backup_step() can be retried later on. ^(If
6566: ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
6567: ** [SQLITE_READONLY] is returned, then
6568: ** there is no point in retrying the call to sqlite3_backup_step(). These
6569: ** errors are considered fatal.)^ The application must accept
6570: ** that the backup operation has failed and pass the backup operation handle
6571: ** to the sqlite3_backup_finish() to release associated resources.
6572: **
6573: ** ^The first call to sqlite3_backup_step() obtains an exclusive lock
6574: ** on the destination file. ^The exclusive lock is not released until either
6575: ** sqlite3_backup_finish() is called or the backup operation is complete
6576: ** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to
6577: ** sqlite3_backup_step() obtains a [shared lock] on the source database that
6578: ** lasts for the duration of the sqlite3_backup_step() call.
6579: ** ^Because the source database is not locked between calls to
6580: ** sqlite3_backup_step(), the source database may be modified mid-way
6581: ** through the backup process. ^If the source database is modified by an
6582: ** external process or via a database connection other than the one being
6583: ** used by the backup operation, then the backup will be automatically
6584: ** restarted by the next call to sqlite3_backup_step(). ^If the source
6585: ** database is modified by the using the same database connection as is used
6586: ** by the backup operation, then the backup database is automatically
6587: ** updated at the same time.
6588: **
6589: ** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
6590: **
6591: ** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the
6592: ** application wishes to abandon the backup operation, the application
6593: ** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
6594: ** ^The sqlite3_backup_finish() interfaces releases all
6595: ** resources associated with the [sqlite3_backup] object.
6596: ** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
6597: ** active write-transaction on the destination database is rolled back.
6598: ** The [sqlite3_backup] object is invalid
6599: ** and may not be used following a call to sqlite3_backup_finish().
6600: **
6601: ** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
6602: ** sqlite3_backup_step() errors occurred, regardless or whether or not
6603: ** sqlite3_backup_step() completed.
6604: ** ^If an out-of-memory condition or IO error occurred during any prior
6605: ** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
6606: ** sqlite3_backup_finish() returns the corresponding [error code].
6607: **
6608: ** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
6609: ** is not a permanent error and does not affect the return value of
6610: ** sqlite3_backup_finish().
6611: **
6612: ** [[sqlite3_backup__remaining()]] [[sqlite3_backup_pagecount()]]
6613: ** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
6614: **
6615: ** ^Each call to sqlite3_backup_step() sets two values inside
6616: ** the [sqlite3_backup] object: the number of pages still to be backed
6617: ** up and the total number of pages in the source database file.
6618: ** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces
6619: ** retrieve these two values, respectively.
6620: **
6621: ** ^The values returned by these functions are only updated by
6622: ** sqlite3_backup_step(). ^If the source database is modified during a backup
6623: ** operation, then the values are not updated to account for any extra
6624: ** pages that need to be updated or the size of the source database file
6625: ** changing.
6626: **
6627: ** <b>Concurrent Usage of Database Handles</b>
6628: **
6629: ** ^The source [database connection] may be used by the application for other
6630: ** purposes while a backup operation is underway or being initialized.
6631: ** ^If SQLite is compiled and configured to support threadsafe database
6632: ** connections, then the source database connection may be used concurrently
6633: ** from within other threads.
6634: **
6635: ** However, the application must guarantee that the destination
6636: ** [database connection] is not passed to any other API (by any thread) after
6637: ** sqlite3_backup_init() is called and before the corresponding call to
6638: ** sqlite3_backup_finish(). SQLite does not currently check to see
6639: ** if the application incorrectly accesses the destination [database connection]
6640: ** and so no error code is reported, but the operations may malfunction
6641: ** nevertheless. Use of the destination database connection while a
6642: ** backup is in progress might also also cause a mutex deadlock.
6643: **
6644: ** If running in [shared cache mode], the application must
6645: ** guarantee that the shared cache used by the destination database
6646: ** is not accessed while the backup is running. In practice this means
6647: ** that the application must guarantee that the disk file being
6648: ** backed up to is not accessed by any connection within the process,
6649: ** not just the specific connection that was passed to sqlite3_backup_init().
6650: **
6651: ** The [sqlite3_backup] object itself is partially threadsafe. Multiple
6652: ** threads may safely make multiple concurrent calls to sqlite3_backup_step().
6653: ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
6654: ** APIs are not strictly speaking threadsafe. If they are invoked at the
6655: ** same time as another thread is invoking sqlite3_backup_step() it is
6656: ** possible that they return invalid values.
6657: */
6658: SQLITE_API sqlite3_backup *sqlite3_backup_init(
6659: sqlite3 *pDest, /* Destination database handle */
6660: const char *zDestName, /* Destination database name */
6661: sqlite3 *pSource, /* Source database handle */
6662: const char *zSourceName /* Source database name */
6663: );
6664: SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage);
6665: SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p);
6666: SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p);
6667: SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p);
6668:
6669: /*
6670: ** CAPI3REF: Unlock Notification
6671: **
6672: ** ^When running in shared-cache mode, a database operation may fail with
6673: ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
6674: ** individual tables within the shared-cache cannot be obtained. See
6675: ** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
6676: ** ^This API may be used to register a callback that SQLite will invoke
6677: ** when the connection currently holding the required lock relinquishes it.
6678: ** ^This API is only available if the library was compiled with the
6679: ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
6680: **
6681: ** See Also: [Using the SQLite Unlock Notification Feature].
6682: **
6683: ** ^Shared-cache locks are released when a database connection concludes
6684: ** its current transaction, either by committing it or rolling it back.
6685: **
6686: ** ^When a connection (known as the blocked connection) fails to obtain a
6687: ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
6688: ** identity of the database connection (the blocking connection) that
6689: ** has locked the required resource is stored internally. ^After an
6690: ** application receives an SQLITE_LOCKED error, it may call the
6691: ** sqlite3_unlock_notify() method with the blocked connection handle as
6692: ** the first argument to register for a callback that will be invoked
6693: ** when the blocking connections current transaction is concluded. ^The
6694: ** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
6695: ** call that concludes the blocking connections transaction.
6696: **
6697: ** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
6698: ** there is a chance that the blocking connection will have already
6699: ** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
6700: ** If this happens, then the specified callback is invoked immediately,
6701: ** from within the call to sqlite3_unlock_notify().)^
6702: **
6703: ** ^If the blocked connection is attempting to obtain a write-lock on a
6704: ** shared-cache table, and more than one other connection currently holds
6705: ** a read-lock on the same table, then SQLite arbitrarily selects one of
6706: ** the other connections to use as the blocking connection.
6707: **
6708: ** ^(There may be at most one unlock-notify callback registered by a
6709: ** blocked connection. If sqlite3_unlock_notify() is called when the
6710: ** blocked connection already has a registered unlock-notify callback,
6711: ** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
6712: ** called with a NULL pointer as its second argument, then any existing
6713: ** unlock-notify callback is canceled. ^The blocked connections
6714: ** unlock-notify callback may also be canceled by closing the blocked
6715: ** connection using [sqlite3_close()].
6716: **
6717: ** The unlock-notify callback is not reentrant. If an application invokes
6718: ** any sqlite3_xxx API functions from within an unlock-notify callback, a
6719: ** crash or deadlock may be the result.
6720: **
6721: ** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
6722: ** returns SQLITE_OK.
6723: **
6724: ** <b>Callback Invocation Details</b>
6725: **
6726: ** When an unlock-notify callback is registered, the application provides a
6727: ** single void* pointer that is passed to the callback when it is invoked.
6728: ** However, the signature of the callback function allows SQLite to pass
6729: ** it an array of void* context pointers. The first argument passed to
6730: ** an unlock-notify callback is a pointer to an array of void* pointers,
6731: ** and the second is the number of entries in the array.
6732: **
6733: ** When a blocking connections transaction is concluded, there may be
6734: ** more than one blocked connection that has registered for an unlock-notify
6735: ** callback. ^If two or more such blocked connections have specified the
6736: ** same callback function, then instead of invoking the callback function
6737: ** multiple times, it is invoked once with the set of void* context pointers
6738: ** specified by the blocked connections bundled together into an array.
6739: ** This gives the application an opportunity to prioritize any actions
6740: ** related to the set of unblocked database connections.
6741: **
6742: ** <b>Deadlock Detection</b>
6743: **
6744: ** Assuming that after registering for an unlock-notify callback a
6745: ** database waits for the callback to be issued before taking any further
6746: ** action (a reasonable assumption), then using this API may cause the
6747: ** application to deadlock. For example, if connection X is waiting for
6748: ** connection Y's transaction to be concluded, and similarly connection
6749: ** Y is waiting on connection X's transaction, then neither connection
6750: ** will proceed and the system may remain deadlocked indefinitely.
6751: **
6752: ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
6753: ** detection. ^If a given call to sqlite3_unlock_notify() would put the
6754: ** system in a deadlocked state, then SQLITE_LOCKED is returned and no
6755: ** unlock-notify callback is registered. The system is said to be in
6756: ** a deadlocked state if connection A has registered for an unlock-notify
6757: ** callback on the conclusion of connection B's transaction, and connection
6758: ** B has itself registered for an unlock-notify callback when connection
6759: ** A's transaction is concluded. ^Indirect deadlock is also detected, so
6760: ** the system is also considered to be deadlocked if connection B has
6761: ** registered for an unlock-notify callback on the conclusion of connection
6762: ** C's transaction, where connection C is waiting on connection A. ^Any
6763: ** number of levels of indirection are allowed.
6764: **
6765: ** <b>The "DROP TABLE" Exception</b>
6766: **
6767: ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost
6768: ** always appropriate to call sqlite3_unlock_notify(). There is however,
6769: ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
6770: ** SQLite checks if there are any currently executing SELECT statements
6771: ** that belong to the same connection. If there are, SQLITE_LOCKED is
6772: ** returned. In this case there is no "blocking connection", so invoking
6773: ** sqlite3_unlock_notify() results in the unlock-notify callback being
6774: ** invoked immediately. If the application then re-attempts the "DROP TABLE"
6775: ** or "DROP INDEX" query, an infinite loop might be the result.
6776: **
6777: ** One way around this problem is to check the extended error code returned
6778: ** by an sqlite3_step() call. ^(If there is a blocking connection, then the
6779: ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
6780: ** the special "DROP TABLE/INDEX" case, the extended error code is just
6781: ** SQLITE_LOCKED.)^
6782: */
6783: SQLITE_API int sqlite3_unlock_notify(
6784: sqlite3 *pBlocked, /* Waiting connection */
6785: void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */
6786: void *pNotifyArg /* Argument to pass to xNotify */
6787: );
6788:
6789:
6790: /*
6791: ** CAPI3REF: String Comparison
6792: **
1.3 ! misho 6793: ** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications
! 6794: ** and extensions to compare the contents of two buffers containing UTF-8
! 6795: ** strings in a case-independent fashion, using the same definition of "case
! 6796: ** independence" that SQLite uses internally when comparing identifiers.
1.2 misho 6797: */
1.3 ! misho 6798: SQLITE_API int sqlite3_stricmp(const char *, const char *);
1.2 misho 6799: SQLITE_API int sqlite3_strnicmp(const char *, const char *, int);
6800:
6801: /*
6802: ** CAPI3REF: Error Logging Interface
6803: **
6804: ** ^The [sqlite3_log()] interface writes a message into the error log
6805: ** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
6806: ** ^If logging is enabled, the zFormat string and subsequent arguments are
6807: ** used with [sqlite3_snprintf()] to generate the final output string.
6808: **
6809: ** The sqlite3_log() interface is intended for use by extensions such as
6810: ** virtual tables, collating functions, and SQL functions. While there is
6811: ** nothing to prevent an application from calling sqlite3_log(), doing so
6812: ** is considered bad form.
6813: **
6814: ** The zFormat string must not be NULL.
6815: **
6816: ** To avoid deadlocks and other threading problems, the sqlite3_log() routine
6817: ** will not use dynamically allocated memory. The log message is stored in
6818: ** a fixed-length buffer on the stack. If the log message is longer than
6819: ** a few hundred characters, it will be truncated to the length of the
6820: ** buffer.
6821: */
6822: SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...);
6823:
6824: /*
6825: ** CAPI3REF: Write-Ahead Log Commit Hook
6826: **
6827: ** ^The [sqlite3_wal_hook()] function is used to register a callback that
6828: ** will be invoked each time a database connection commits data to a
6829: ** [write-ahead log] (i.e. whenever a transaction is committed in
6830: ** [journal_mode | journal_mode=WAL mode]).
6831: **
6832: ** ^The callback is invoked by SQLite after the commit has taken place and
6833: ** the associated write-lock on the database released, so the implementation
6834: ** may read, write or [checkpoint] the database as required.
6835: **
6836: ** ^The first parameter passed to the callback function when it is invoked
6837: ** is a copy of the third parameter passed to sqlite3_wal_hook() when
6838: ** registering the callback. ^The second is a copy of the database handle.
6839: ** ^The third parameter is the name of the database that was written to -
6840: ** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
6841: ** is the number of pages currently in the write-ahead log file,
6842: ** including those that were just committed.
6843: **
6844: ** The callback function should normally return [SQLITE_OK]. ^If an error
6845: ** code is returned, that error will propagate back up through the
6846: ** SQLite code base to cause the statement that provoked the callback
6847: ** to report an error, though the commit will have still occurred. If the
6848: ** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
6849: ** that does not correspond to any valid SQLite error code, the results
6850: ** are undefined.
6851: **
6852: ** A single database handle may have at most a single write-ahead log callback
6853: ** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
6854: ** previously registered write-ahead log callback. ^Note that the
6855: ** [sqlite3_wal_autocheckpoint()] interface and the
6856: ** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
6857: ** those overwrite any prior [sqlite3_wal_hook()] settings.
6858: */
6859: SQLITE_API void *sqlite3_wal_hook(
6860: sqlite3*,
6861: int(*)(void *,sqlite3*,const char*,int),
6862: void*
6863: );
6864:
6865: /*
6866: ** CAPI3REF: Configure an auto-checkpoint
6867: **
6868: ** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
6869: ** [sqlite3_wal_hook()] that causes any database on [database connection] D
6870: ** to automatically [checkpoint]
6871: ** after committing a transaction if there are N or
6872: ** more frames in the [write-ahead log] file. ^Passing zero or
6873: ** a negative value as the nFrame parameter disables automatic
6874: ** checkpoints entirely.
6875: **
6876: ** ^The callback registered by this function replaces any existing callback
6877: ** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback
6878: ** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
6879: ** configured by this function.
6880: **
6881: ** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
6882: ** from SQL.
6883: **
6884: ** ^Every new [database connection] defaults to having the auto-checkpoint
6885: ** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
6886: ** pages. The use of this interface
6887: ** is only necessary if the default setting is found to be suboptimal
6888: ** for a particular application.
6889: */
6890: SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
6891:
6892: /*
6893: ** CAPI3REF: Checkpoint a database
6894: **
6895: ** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X
6896: ** on [database connection] D to be [checkpointed]. ^If X is NULL or an
6897: ** empty string, then a checkpoint is run on all databases of
6898: ** connection D. ^If the database connection D is not in
6899: ** [WAL | write-ahead log mode] then this interface is a harmless no-op.
6900: **
6901: ** ^The [wal_checkpoint pragma] can be used to invoke this interface
6902: ** from SQL. ^The [sqlite3_wal_autocheckpoint()] interface and the
6903: ** [wal_autocheckpoint pragma] can be used to cause this interface to be
6904: ** run whenever the WAL reaches a certain size threshold.
6905: **
6906: ** See also: [sqlite3_wal_checkpoint_v2()]
6907: */
6908: SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
6909:
6910: /*
6911: ** CAPI3REF: Checkpoint a database
6912: **
6913: ** Run a checkpoint operation on WAL database zDb attached to database
6914: ** handle db. The specific operation is determined by the value of the
6915: ** eMode parameter:
6916: **
6917: ** <dl>
6918: ** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
6919: ** Checkpoint as many frames as possible without waiting for any database
6920: ** readers or writers to finish. Sync the db file if all frames in the log
6921: ** are checkpointed. This mode is the same as calling
6922: ** sqlite3_wal_checkpoint(). The busy-handler callback is never invoked.
6923: **
6924: ** <dt>SQLITE_CHECKPOINT_FULL<dd>
6925: ** This mode blocks (calls the busy-handler callback) until there is no
6926: ** database writer and all readers are reading from the most recent database
6927: ** snapshot. It then checkpoints all frames in the log file and syncs the
6928: ** database file. This call blocks database writers while it is running,
6929: ** but not database readers.
6930: **
6931: ** <dt>SQLITE_CHECKPOINT_RESTART<dd>
6932: ** This mode works the same way as SQLITE_CHECKPOINT_FULL, except after
6933: ** checkpointing the log file it blocks (calls the busy-handler callback)
6934: ** until all readers are reading from the database file only. This ensures
6935: ** that the next client to write to the database file restarts the log file
6936: ** from the beginning. This call blocks database writers while it is running,
6937: ** but not database readers.
6938: ** </dl>
6939: **
6940: ** If pnLog is not NULL, then *pnLog is set to the total number of frames in
6941: ** the log file before returning. If pnCkpt is not NULL, then *pnCkpt is set to
6942: ** the total number of checkpointed frames (including any that were already
6943: ** checkpointed when this function is called). *pnLog and *pnCkpt may be
6944: ** populated even if sqlite3_wal_checkpoint_v2() returns other than SQLITE_OK.
6945: ** If no values are available because of an error, they are both set to -1
6946: ** before returning to communicate this to the caller.
6947: **
6948: ** All calls obtain an exclusive "checkpoint" lock on the database file. If
6949: ** any other process is running a checkpoint operation at the same time, the
6950: ** lock cannot be obtained and SQLITE_BUSY is returned. Even if there is a
6951: ** busy-handler configured, it will not be invoked in this case.
6952: **
6953: ** The SQLITE_CHECKPOINT_FULL and RESTART modes also obtain the exclusive
6954: ** "writer" lock on the database file. If the writer lock cannot be obtained
6955: ** immediately, and a busy-handler is configured, it is invoked and the writer
6956: ** lock retried until either the busy-handler returns 0 or the lock is
6957: ** successfully obtained. The busy-handler is also invoked while waiting for
6958: ** database readers as described above. If the busy-handler returns 0 before
6959: ** the writer lock is obtained or while waiting for database readers, the
6960: ** checkpoint operation proceeds from that point in the same way as
6961: ** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible
6962: ** without blocking any further. SQLITE_BUSY is returned in this case.
6963: **
6964: ** If parameter zDb is NULL or points to a zero length string, then the
6965: ** specified operation is attempted on all WAL databases. In this case the
6966: ** values written to output parameters *pnLog and *pnCkpt are undefined. If
6967: ** an SQLITE_BUSY error is encountered when processing one or more of the
6968: ** attached WAL databases, the operation is still attempted on any remaining
6969: ** attached databases and SQLITE_BUSY is returned to the caller. If any other
6970: ** error occurs while processing an attached database, processing is abandoned
6971: ** and the error code returned to the caller immediately. If no error
6972: ** (SQLITE_BUSY or otherwise) is encountered while processing the attached
6973: ** databases, SQLITE_OK is returned.
6974: **
6975: ** If database zDb is the name of an attached database that is not in WAL
6976: ** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. If
6977: ** zDb is not NULL (or a zero length string) and is not the name of any
6978: ** attached database, SQLITE_ERROR is returned to the caller.
6979: */
6980: SQLITE_API int sqlite3_wal_checkpoint_v2(
6981: sqlite3 *db, /* Database handle */
6982: const char *zDb, /* Name of attached database (or NULL) */
6983: int eMode, /* SQLITE_CHECKPOINT_* value */
6984: int *pnLog, /* OUT: Size of WAL log in frames */
6985: int *pnCkpt /* OUT: Total number of frames checkpointed */
6986: );
6987:
6988: /*
6989: ** CAPI3REF: Checkpoint operation parameters
6990: **
6991: ** These constants can be used as the 3rd parameter to
6992: ** [sqlite3_wal_checkpoint_v2()]. See the [sqlite3_wal_checkpoint_v2()]
6993: ** documentation for additional information about the meaning and use of
6994: ** each of these values.
6995: */
6996: #define SQLITE_CHECKPOINT_PASSIVE 0
6997: #define SQLITE_CHECKPOINT_FULL 1
6998: #define SQLITE_CHECKPOINT_RESTART 2
6999:
7000: /*
7001: ** CAPI3REF: Virtual Table Interface Configuration
7002: **
7003: ** This function may be called by either the [xConnect] or [xCreate] method
7004: ** of a [virtual table] implementation to configure
7005: ** various facets of the virtual table interface.
7006: **
7007: ** If this interface is invoked outside the context of an xConnect or
7008: ** xCreate virtual table method then the behavior is undefined.
7009: **
7010: ** At present, there is only one option that may be configured using
7011: ** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options
7012: ** may be added in the future.
7013: */
7014: SQLITE_API int sqlite3_vtab_config(sqlite3*, int op, ...);
7015:
7016: /*
7017: ** CAPI3REF: Virtual Table Configuration Options
7018: **
7019: ** These macros define the various options to the
7020: ** [sqlite3_vtab_config()] interface that [virtual table] implementations
7021: ** can use to customize and optimize their behavior.
7022: **
7023: ** <dl>
7024: ** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT
7025: ** <dd>Calls of the form
7026: ** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
7027: ** where X is an integer. If X is zero, then the [virtual table] whose
7028: ** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not
7029: ** support constraints. In this configuration (which is the default) if
7030: ** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire
7031: ** statement is rolled back as if [ON CONFLICT | OR ABORT] had been
7032: ** specified as part of the users SQL statement, regardless of the actual
7033: ** ON CONFLICT mode specified.
7034: **
7035: ** If X is non-zero, then the virtual table implementation guarantees
7036: ** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before
7037: ** any modifications to internal or persistent data structures have been made.
7038: ** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite
7039: ** is able to roll back a statement or database transaction, and abandon
7040: ** or continue processing the current SQL statement as appropriate.
7041: ** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns
7042: ** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode
7043: ** had been ABORT.
7044: **
7045: ** Virtual table implementations that are required to handle OR REPLACE
7046: ** must do so within the [xUpdate] method. If a call to the
7047: ** [sqlite3_vtab_on_conflict()] function indicates that the current ON
7048: ** CONFLICT policy is REPLACE, the virtual table implementation should
7049: ** silently replace the appropriate rows within the xUpdate callback and
7050: ** return SQLITE_OK. Or, if this is not possible, it may return
7051: ** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT
7052: ** constraint handling.
7053: ** </dl>
7054: */
7055: #define SQLITE_VTAB_CONSTRAINT_SUPPORT 1
7056:
7057: /*
7058: ** CAPI3REF: Determine The Virtual Table Conflict Policy
7059: **
7060: ** This function may only be called from within a call to the [xUpdate] method
7061: ** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The
7062: ** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
7063: ** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
7064: ** of the SQL statement that triggered the call to the [xUpdate] method of the
7065: ** [virtual table].
7066: */
7067: SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *);
7068:
7069: /*
7070: ** CAPI3REF: Conflict resolution modes
7071: **
7072: ** These constants are returned by [sqlite3_vtab_on_conflict()] to
7073: ** inform a [virtual table] implementation what the [ON CONFLICT] mode
7074: ** is for the SQL statement being evaluated.
7075: **
7076: ** Note that the [SQLITE_IGNORE] constant is also used as a potential
7077: ** return value from the [sqlite3_set_authorizer()] callback and that
7078: ** [SQLITE_ABORT] is also a [result code].
7079: */
7080: #define SQLITE_ROLLBACK 1
7081: /* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
7082: #define SQLITE_FAIL 3
7083: /* #define SQLITE_ABORT 4 // Also an error code */
7084: #define SQLITE_REPLACE 5
7085:
7086:
7087:
7088: /*
7089: ** Undo the hack that converts floating point types to integer for
7090: ** builds on processors without floating point support.
7091: */
7092: #ifdef SQLITE_OMIT_FLOATING_POINT
7093: # undef double
7094: #endif
7095:
7096: #ifdef __cplusplus
7097: } /* End of the 'extern "C"' block */
7098: #endif
7099: #endif
7100:
7101: /*
7102: ** 2010 August 30
7103: **
7104: ** The author disclaims copyright to this source code. In place of
7105: ** a legal notice, here is a blessing:
7106: **
7107: ** May you do good and not evil.
7108: ** May you find forgiveness for yourself and forgive others.
7109: ** May you share freely, never taking more than you give.
7110: **
7111: *************************************************************************
7112: */
7113:
7114: #ifndef _SQLITE3RTREE_H_
7115: #define _SQLITE3RTREE_H_
7116:
7117:
7118: #ifdef __cplusplus
7119: extern "C" {
7120: #endif
7121:
7122: typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry;
7123:
7124: /*
7125: ** Register a geometry callback named zGeom that can be used as part of an
7126: ** R-Tree geometry query as follows:
7127: **
7128: ** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...)
7129: */
7130: SQLITE_API int sqlite3_rtree_geometry_callback(
7131: sqlite3 *db,
7132: const char *zGeom,
1.3 ! misho 7133: #ifdef SQLITE_RTREE_INT_ONLY
! 7134: int (*xGeom)(sqlite3_rtree_geometry*, int n, sqlite3_int64 *a, int *pRes),
! 7135: #else
! 7136: int (*xGeom)(sqlite3_rtree_geometry*, int n, double *a, int *pRes),
! 7137: #endif
1.2 misho 7138: void *pContext
7139: );
7140:
7141:
7142: /*
7143: ** A pointer to a structure of the following type is passed as the first
7144: ** argument to callbacks registered using rtree_geometry_callback().
7145: */
7146: struct sqlite3_rtree_geometry {
7147: void *pContext; /* Copy of pContext passed to s_r_g_c() */
7148: int nParam; /* Size of array aParam[] */
7149: double *aParam; /* Parameters passed to SQL geom function */
7150: void *pUser; /* Callback implementation user data */
7151: void (*xDelUser)(void *); /* Called by SQLite to clean up pUser */
7152: };
7153:
7154:
7155: #ifdef __cplusplus
7156: } /* end of the 'extern "C"' block */
7157: #endif
7158:
7159: #endif /* ifndef _SQLITE3RTREE_H_ */
7160:
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