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1/*
2** 2001 September 15
3**
4** The author disclaims copyright to this source code. In place of
5** a legal notice, here is a blessing:
6**
7** May you do good and not evil.
8** May you find forgiveness for yourself and forgive others.
9** May you share freely, never taking more than you give.
10**
11*************************************************************************
12** This header file defines the interface that the SQLite library
13** presents to client programs. If a C-function, structure, datatype,
14** or constant definition does not appear in this file, then it is
15** not a published API of SQLite, is subject to change without
16** notice, and should not be referenced by programs that use SQLite.
17**
18** Some of the definitions that are in this file are marked as
19** "experimental". Experimental interfaces are normally new
20** features recently added to SQLite. We do not anticipate changes
21** to experimental interfaces but reserve to make minor changes if
22** 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** @(#) $Id: sqlite.h.in,v 1.266 2007/10/03 20:15:28 drh Exp $
34*/
35#ifndef _SQLITE3_H_
36#define _SQLITE3_H_
37#include <stdarg.h> /* Needed for the definition of va_list */
38
39/*
40** Make sure we can call this stuff from C++.
41*/
42#ifdef __cplusplus
43extern "C" {
44#endif
45
46
47/*
48** Add the ability to override 'extern'
49*/
50#ifndef SQLITE_EXTERN
51# define SQLITE_EXTERN extern
52#endif
53
54/*
55** Make sure these symbols where not defined by some previous header
56** file.
57*/
58#ifdef SQLITE_VERSION
59# undef SQLITE_VERSION
60#endif
61#ifdef SQLITE_VERSION_NUMBER
62# undef SQLITE_VERSION_NUMBER
63#endif
64
65/*
66** CAPI3REF: Compile-Time Library Version Numbers
67**
68** The version of the SQLite library is contained in the sqlite3.h
69** header file in a #define named SQLITE_VERSION. The SQLITE_VERSION
70** macro resolves to a string constant.
71**
72** The format of the version string is "X.Y.Z", where
73** X is the major version number, Y is the minor version number and Z
74** is the release number. The X.Y.Z might be followed by "alpha" or "beta".
75** For example "3.1.1beta".
76**
77** The X value is always 3 in SQLite. The X value only changes when
78** backwards compatibility is broken and we intend to never break
79** backwards compatibility. The Y value only changes when
80** there are major feature enhancements that are forwards compatible
81** but not backwards compatible. The Z value is incremented with
82** each release but resets back to 0 when Y is incremented.
83**
84** The SQLITE_VERSION_NUMBER is an integer with the value
85** (X*1000000 + Y*1000 + Z). For example, for version "3.1.1beta",
86** SQLITE_VERSION_NUMBER is set to 3001001. To detect if they are using
87** version 3.1.1 or greater at compile time, programs may use the test
88** (SQLITE_VERSION_NUMBER>=3001001).
89**
90** See also: [sqlite3_libversion()] and [sqlite3_libversion_number()].
91*/
92#define SQLITE_VERSION "3.5.1"
93#define SQLITE_VERSION_NUMBER 3005001
94
95/*
96** CAPI3REF: Run-Time Library Version Numbers
97**
98** These routines return values equivalent to the header constants
99** [SQLITE_VERSION] and [SQLITE_VERSION_NUMBER]. The values returned
100** by this routines should only be different from the header values
101** if you compile your program using an sqlite3.h header from a
102** different version of SQLite that the version of the library you
103** link against.
104**
105** The sqlite3_version[] string constant contains the text of the
106** [SQLITE_VERSION] string. The sqlite3_libversion() function returns
107** a poiner to the sqlite3_version[] string constant. The function
108** is provided for DLL users who can only access functions and not
109** constants within the DLL.
110*/
111SQLITE_EXTERN const char sqlite3_version[];
112const char *sqlite3_libversion(void);
113int sqlite3_libversion_number(void);
114
115/*
116** CAPI3REF: Test To See If The Library Is Threadsafe
117**
118** This routine returns TRUE (nonzero) if SQLite was compiled with
119** all of its mutexes enabled and is thus threadsafe. It returns
120** zero if the particular build is for single-threaded operation
121** only.
122**
123** Really all this routine does is return true if SQLite was compiled
124** with the -DSQLITE_THREADSAFE=1 option and false if
125** compiled with -DSQLITE_THREADSAFE=0. If SQLite uses an
126** application-defined mutex subsystem, malloc subsystem, collating
127** sequence, VFS, SQL function, progress callback, commit hook,
128** extension, or other accessories and these add-ons are not
129** threadsafe, then clearly the combination will not be threadsafe
130** either. Hence, this routine never reports that the library
131** is guaranteed to be threadsafe, only when it is guaranteed not
132** to be.
133**
134** This is an experimental API and may go away or change in future
135** releases.
136*/
137int sqlite3_threadsafe(void);
138
139/*
140** CAPI3REF: Database Connection Handle
141**
142** Each open SQLite database is represented by pointer to an instance of the
143** opaque structure named "sqlite3". It is useful to think of an sqlite3
144** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and
145** [sqlite3_open_v2()] interfaces are its constructors
146** and [sqlite3_close()] is its destructor. There are many other interfaces
147** (such as [sqlite3_prepare_v2()], [sqlite3_create_function()], and
148** [sqlite3_busy_timeout()] to name but three) that are methods on this
149** object.
150*/
151typedef struct sqlite3 sqlite3;
152
153
154/*
155** CAPI3REF: 64-Bit Integer Types
156**
157** Some compilers do not support the "long long" datatype. So we have
158** to do compiler-specific typedefs for 64-bit signed and unsigned integers.
159**
160** Many SQLite interface functions require a 64-bit integer arguments.
161** Those interfaces are declared using this typedef.
162*/
163#ifdef SQLITE_INT64_TYPE
164 typedef SQLITE_INT64_TYPE sqlite_int64;
165 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
166#elif defined(_MSC_VER) || defined(__BORLANDC__)
167 typedef __int64 sqlite_int64;
168 typedef unsigned __int64 sqlite_uint64;
169#else
170 typedef long long int sqlite_int64;
171 typedef unsigned long long int sqlite_uint64;
172#endif
173typedef sqlite_int64 sqlite3_int64;
174typedef sqlite_uint64 sqlite3_uint64;
175
176/*
177** If compiling for a processor that lacks floating point support,
178** substitute integer for floating-point
179*/
180#ifdef SQLITE_OMIT_FLOATING_POINT
181# define double sqlite3_int64
182#endif
183
184/*
185** CAPI3REF: Closing A Database Connection
186**
187** Call this function with a pointer to a structure that was previously
188** returned from [sqlite3_open()], [sqlite3_open16()], or
189** [sqlite3_open_v2()] and the corresponding database will by
190** closed.
191**
192** All SQL statements prepared using [sqlite3_prepare_v2()] or
193** [sqlite3_prepare16_v2()] must be destroyed using [sqlite3_finalize()]
194** before this routine is called. Otherwise, SQLITE_BUSY is returned and the
195** database connection remains open.
196**
197** Passing this routine a database connection that has already been
198** closed results in undefined behavior. If other interfaces that
199** reference the same database connection are pending (either in the
200** same thread or in different threads) when this routine is called,
201** then the behavior is undefined and is almost certainly undesirable.
202*/
203int sqlite3_close(sqlite3 *);
204
205/*
206** The type for a callback function.
207** This is legacy and deprecated. It is included for historical
208** compatibility and is not documented.
209*/
210typedef int (*sqlite3_callback)(void*,int,char**, char**);
211
212/*
213** CAPI3REF: One-Step Query Execution Interface
214**
215** This interface is used to do a one-time evaluatation of zero
216** or more SQL statements. UTF-8 text of the SQL statements to
217** be evaluted is passed in as the second parameter. The statements
218** are prepared one by one using [sqlite3_prepare()], evaluated
219** using [sqlite3_step()], then destroyed using [sqlite3_finalize()].
220**
221** If one or more of the SQL statements are queries, then
222** the callback function specified by the 3rd parameter is
223** invoked once for each row of the query result. This callback
224** should normally return 0. If the callback returns a non-zero
225** value then the query is aborted, all subsequent SQL statements
226** are skipped and the sqlite3_exec() function returns the [SQLITE_ABORT].
227**
228** The 4th parameter to this interface is an arbitrary pointer that is
229** passed through to the callback function as its first parameter.
230**
231** The 2nd parameter to the callback function is the number of
232** columns in the query result. The 3rd parameter to the callback
233** is an array of strings holding the values for each column
234** as extracted using [sqlite3_column_text()].
235** The 4th parameter to the callback is an array of strings
236** obtained using [sqlite3_column_name()] and holding
237** the names of each column.
238**
239** The callback function may be NULL, even for queries. A NULL
240** callback is not an error. It just means that no callback
241** will be invoked.
242**
243** If an error occurs while parsing or evaluating the SQL (but
244** not while executing the callback) then an appropriate error
245** message is written into memory obtained from [sqlite3_malloc()] and
246** *errmsg is made to point to that message. The calling function
247** is responsible for freeing the memory using [sqlite3_free()].
248** If errmsg==NULL, then no error message is ever written.
249**
250** The return value is is SQLITE_OK if there are no errors and
251** some other [SQLITE_OK | return code] if there is an error.
252** The particular return value depends on the type of error.
253**
254*/
255int sqlite3_exec(
256 sqlite3*, /* An open database */
257 const char *sql, /* SQL to be evaluted */
258 int (*callback)(void*,int,char**,char**), /* Callback function */
259 void *, /* 1st argument to callback */
260 char **errmsg /* Error msg written here */
261);
262
263/*
264** CAPI3REF: Result Codes
265** KEYWORDS: SQLITE_OK
266**
267** Many SQLite functions return an integer result code from the set shown
268** above in order to indicates success or failure.
269**
270** The result codes above are the only ones returned by SQLite in its
271** default configuration. However, the [sqlite3_extended_result_codes()]
272** API can be used to set a database connectoin to return more detailed
273** result codes.
274**
275** See also: [SQLITE_IOERR_READ | extended result codes]
276**
277*/
278#define SQLITE_OK 0 /* Successful result */
279/* beginning-of-error-codes */
280#define SQLITE_ERROR 1 /* SQL error or missing database */
281#define SQLITE_INTERNAL 2 /* NOT USED. Internal logic error in SQLite */
282#define SQLITE_PERM 3 /* Access permission denied */
283#define SQLITE_ABORT 4 /* Callback routine requested an abort */
284#define SQLITE_BUSY 5 /* The database file is locked */
285#define SQLITE_LOCKED 6 /* A table in the database is locked */
286#define SQLITE_NOMEM 7 /* A malloc() failed */
287#define SQLITE_READONLY 8 /* Attempt to write a readonly database */
288#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/
289#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */
290#define SQLITE_CORRUPT 11 /* The database disk image is malformed */
291#define SQLITE_NOTFOUND 12 /* NOT USED. Table or record not found */
292#define SQLITE_FULL 13 /* Insertion failed because database is full */
293#define SQLITE_CANTOPEN 14 /* Unable to open the database file */
294#define SQLITE_PROTOCOL 15 /* NOT USED. Database lock protocol error */
295#define SQLITE_EMPTY 16 /* Database is empty */
296#define SQLITE_SCHEMA 17 /* The database schema changed */
297#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */
298#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */
299#define SQLITE_MISMATCH 20 /* Data type mismatch */
300#define SQLITE_MISUSE 21 /* Library used incorrectly */
301#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */
302#define SQLITE_AUTH 23 /* Authorization denied */
303#define SQLITE_FORMAT 24 /* Auxiliary database format error */
304#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */
305#define SQLITE_NOTADB 26 /* File opened that is not a database file */
306#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */
307#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */
308/* end-of-error-codes */
309
310/*
311** CAPI3REF: Extended Result Codes
312**
313** In its default configuration, SQLite API routines return one of 26 integer
314** result codes described at result-codes. However, experience has shown that
315** many of these result codes are too course-grained. They do not provide as
316** much information about problems as users might like. In an effort to
317** address this, newer versions of SQLite (version 3.3.8 and later) include
318** support for additional result codes that provide more detailed information
319** about errors. The extended result codes are enabled (or disabled) for
320** each database
321** connection using the [sqlite3_extended_result_codes()] API.
322**
323** Some of the available extended result codes are listed above.
324** We expect the number of extended result codes will be expand
325** over time. Software that uses extended result codes should expect
326** to see new result codes in future releases of SQLite.
327**
328** The symbolic name for an extended result code always contains a related
329** primary result code as a prefix. Primary result codes contain a single
330** "_" character. Extended result codes contain two or more "_" characters.
331** The numeric value of an extended result code can be converted to its
332** corresponding primary result code by masking off the lower 8 bytes.
333**
334** The SQLITE_OK result code will never be extended. It will always
335** be exactly zero.
336*/
337#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8))
338#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8))
339#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8))
340#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8))
341#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8))
342#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8))
343#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8))
344#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8))
345#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8))
346#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8))
347#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8))
348#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8))
349
350/*
351** CAPI3REF: Flags For File Open Operations
352**
353** Combination of the following bit values are used as the
354** third argument to the [sqlite3_open_v2()] interface and
355** as fourth argument to the xOpen method of the
356** [sqlite3_vfs] object.
357**
358*/
359#define SQLITE_OPEN_READONLY 0x00000001
360#define SQLITE_OPEN_READWRITE 0x00000002
361#define SQLITE_OPEN_CREATE 0x00000004
362#define SQLITE_OPEN_DELETEONCLOSE 0x00000008
363#define SQLITE_OPEN_EXCLUSIVE 0x00000010
364#define SQLITE_OPEN_MAIN_DB 0x00000100
365#define SQLITE_OPEN_TEMP_DB 0x00000200
366#define SQLITE_OPEN_TRANSIENT_DB 0x00000400
367#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800
368#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000
369#define SQLITE_OPEN_SUBJOURNAL 0x00002000
370#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000
371
372/*
373** CAPI3REF: Device Characteristics
374**
375** The xDeviceCapabilities method of the [sqlite3_io_methods]
376** object returns an integer which is a vector of the following
377** bit values expressing I/O characteristics of the mass storage
378** device that holds the file that the [sqlite3_io_methods]
379** refers to.
380**
381** The SQLITE_IOCAP_ATOMIC property means that all writes of
382** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
383** mean that writes of blocks that are nnn bytes in size and
384** are aligned to an address which is an integer multiple of
385** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
386** that when data is appended to a file, the data is appended
387** first then the size of the file is extended, never the other
388** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
389** information is written to disk in the same order as calls
390** to xWrite().
391*/
392#define SQLITE_IOCAP_ATOMIC 0x00000001
393#define SQLITE_IOCAP_ATOMIC512 0x00000002
394#define SQLITE_IOCAP_ATOMIC1K 0x00000004
395#define SQLITE_IOCAP_ATOMIC2K 0x00000008
396#define SQLITE_IOCAP_ATOMIC4K 0x00000010
397#define SQLITE_IOCAP_ATOMIC8K 0x00000020
398#define SQLITE_IOCAP_ATOMIC16K 0x00000040
399#define SQLITE_IOCAP_ATOMIC32K 0x00000080
400#define SQLITE_IOCAP_ATOMIC64K 0x00000100
401#define SQLITE_IOCAP_SAFE_APPEND 0x00000200
402#define SQLITE_IOCAP_SEQUENTIAL 0x00000400
403
404/*
405** CAPI3REF: File Locking Levels
406**
407** SQLite uses one of the following integer values as the second
408** argument to calls it makes to the xLock() and xUnlock() methods
409** of an [sqlite3_io_methods] object.
410*/
411#define SQLITE_LOCK_NONE 0
412#define SQLITE_LOCK_SHARED 1
413#define SQLITE_LOCK_RESERVED 2
414#define SQLITE_LOCK_PENDING 3
415#define SQLITE_LOCK_EXCLUSIVE 4
416
417/*
418** CAPI3REF: Synchronization Type Flags
419**
420** When SQLite invokes the xSync() method of an [sqlite3_io_methods]
421** object it uses a combination of the following integer values as
422** the second argument.
423**
424** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
425** sync operation only needs to flush data to mass storage. Inode
426** information need not be flushed. The SQLITE_SYNC_NORMAL means
427** to use normal fsync() semantics. The SQLITE_SYNC_FULL flag means
428** to use Mac OS-X style fullsync instead of fsync().
429*/
430#define SQLITE_SYNC_NORMAL 0x00002
431#define SQLITE_SYNC_FULL 0x00003
432#define SQLITE_SYNC_DATAONLY 0x00010
433
434
435/*
436** CAPI3REF: OS Interface Open File Handle
437**
438** An [sqlite3_file] object represents an open file in the OS
439** interface layer. Individual OS interface implementations will
440** want to subclass this object by appending additional fields
441** for their own use. The pMethods entry is a pointer to an
442** [sqlite3_io_methods] object that defines methods for performing
443** I/O operations on the open file.
444*/
445typedef struct sqlite3_file sqlite3_file;
446struct sqlite3_file {
447 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */
448};
449
450/*
451** CAPI3REF: OS Interface File Virtual Methods Object
452**
453** Every file opened by the [sqlite3_vfs] xOpen method contains a pointer to
454** an instance of the this object. This object defines the
455** methods used to perform various operations against the open file.
456**
457** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
458** [SQLITE_SYNC_FULL]. The first choice is the normal fsync().
459* The second choice is an
460** OS-X style fullsync. The SQLITE_SYNC_DATA flag may be ORed in to
461** indicate that only the data of the file and not its inode needs to be
462** synced.
463**
464** The integer values to xLock() and xUnlock() are one of
465** <ul>
466** <li> [SQLITE_LOCK_NONE],
467** <li> [SQLITE_LOCK_SHARED],
468** <li> [SQLITE_LOCK_RESERVED],
469** <li> [SQLITE_LOCK_PENDING], or
470** <li> [SQLITE_LOCK_EXCLUSIVE].
471** </ul>
472** xLock() increases the lock. xUnlock() decreases the lock.
473** The xCheckReservedLock() method looks
474** to see if any database connection, either in this
475** process or in some other process, is holding an RESERVED,
476** PENDING, or EXCLUSIVE lock on the file. It returns true
477** if such a lock exists and false if not.
478**
479** The xFileControl() method is a generic interface that allows custom
480** VFS implementations to directly control an open file using the
481** [sqlite3_file_control()] interface. The second "op" argument
482** is an integer opcode. The third
483** argument is a generic pointer which is intended to be a pointer
484** to a structure that may contain arguments or space in which to
485** write return values. Potential uses for xFileControl() might be
486** functions to enable blocking locks with timeouts, to change the
487** locking strategy (for example to use dot-file locks), to inquire
488** about the status of a lock, or to break stale locks. The SQLite
489** core reserves opcodes less than 100 for its own use.
490** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available.
491** Applications that define a custom xFileControl method should use opcodes
492** greater than 100 to avoid conflicts.
493**
494** The xSectorSize() method returns the sector size of the
495** device that underlies the file. The sector size is the
496** minimum write that can be performed without disturbing
497** other bytes in the file. The xDeviceCharacteristics()
498** method returns a bit vector describing behaviors of the
499** underlying device:
500**
501** <ul>
502** <li> [SQLITE_IOCAP_ATOMIC]
503** <li> [SQLITE_IOCAP_ATOMIC512]
504** <li> [SQLITE_IOCAP_ATOMIC1K]
505** <li> [SQLITE_IOCAP_ATOMIC2K]
506** <li> [SQLITE_IOCAP_ATOMIC4K]
507** <li> [SQLITE_IOCAP_ATOMIC8K]
508** <li> [SQLITE_IOCAP_ATOMIC16K]
509** <li> [SQLITE_IOCAP_ATOMIC32K]
510** <li> [SQLITE_IOCAP_ATOMIC64K]
511** <li> [SQLITE_IOCAP_SAFE_APPEND]
512** <li> [SQLITE_IOCAP_SEQUENTIAL]
513** </ul>
514**
515** The SQLITE_IOCAP_ATOMIC property means that all writes of
516** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
517** mean that writes of blocks that are nnn bytes in size and
518** are aligned to an address which is an integer multiple of
519** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
520** that when data is appended to a file, the data is appended
521** first then the size of the file is extended, never the other
522** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
523** information is written to disk in the same order as calls
524** to xWrite().
525*/
526typedef struct sqlite3_io_methods sqlite3_io_methods;
527struct sqlite3_io_methods {
528 int iVersion;
529 int (*xClose)(sqlite3_file*);
530 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
531 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
532 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
533 int (*xSync)(sqlite3_file*, int flags);
534 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
535 int (*xLock)(sqlite3_file*, int);
536 int (*xUnlock)(sqlite3_file*, int);
537 int (*xCheckReservedLock)(sqlite3_file*);
538 int (*xFileControl)(sqlite3_file*, int op, void *pArg);
539 int (*xSectorSize)(sqlite3_file*);
540 int (*xDeviceCharacteristics)(sqlite3_file*);
541 /* Additional methods may be added in future releases */
542};
543
544/*
545** CAPI3REF: Standard File Control Opcodes
546**
547** These integer constants are opcodes for the xFileControl method
548** of the [sqlite3_io_methods] object and to the [sqlite3_file_control()]
549** interface.
550**
551** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This
552** opcode cases the xFileControl method to write the current state of
553** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
554** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
555** into an integer that the pArg argument points to. This capability
556** is used during testing and only needs to be supported when SQLITE_TEST
557** is defined.
558*/
559#define SQLITE_FCNTL_LOCKSTATE 1
560
561/*
562** CAPI3REF: Mutex Handle
563**
564** The mutex module within SQLite defines [sqlite3_mutex] to be an
565** abstract type for a mutex object. The SQLite core never looks
566** at the internal representation of an [sqlite3_mutex]. It only
567** deals with pointers to the [sqlite3_mutex] object.
568**
569** Mutexes are created using [sqlite3_mutex_alloc()].
570*/
571typedef struct sqlite3_mutex sqlite3_mutex;
572
573/*
574** CAPI3REF: OS Interface Object
575**
576** An instance of this object defines the interface between the
577** SQLite core and the underlying operating system. The "vfs"
578** in the name of the object stands for "virtual file system".
579**
580** The iVersion field is initially 1 but may be larger for future
581** versions of SQLite. Additional fields may be appended to this
582** object when the iVersion value is increased.
583**
584** The szOsFile field is the size of the subclassed [sqlite3_file]
585** structure used by this VFS. mxPathname is the maximum length of
586** a pathname in this VFS.
587**
588** Registered vfs modules are kept on a linked list formed by
589** the pNext pointer. The [sqlite3_vfs_register()]
590** and [sqlite3_vfs_unregister()] interfaces manage this list
591** in a thread-safe way. The [sqlite3_vfs_find()] interface
592** searches the list.
593**
594** The pNext field is the only fields in the sqlite3_vfs
595** structure that SQLite will ever modify. SQLite will only access
596** or modify this field while holding a particular static mutex.
597** The application should never modify anything within the sqlite3_vfs
598** object once the object has been registered.
599**
600** The zName field holds the name of the VFS module. The name must
601** be unique across all VFS modules.
602**
603** SQLite will guarantee that the zFilename string passed to
604** xOpen() is a full pathname as generated by xFullPathname() and
605** that the string will be valid and unchanged until xClose() is
606** called. So the [sqlite3_file] can store a pointer to the
607** filename if it needs to remember the filename for some reason.
608**
609** The flags argument to xOpen() is a copy of the flags argument
610** to [sqlite3_open_v2()]. If [sqlite3_open()] or [sqlite3_open16()]
611** is used, then flags is [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE].
612** If xOpen() opens a file read-only then it sets *pOutFlags to
613** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be
614** set.
615**
616** SQLite will also add one of the following flags to the xOpen()
617** call, depending on the object being opened:
618**
619** <ul>
620** <li> [SQLITE_OPEN_MAIN_DB]
621** <li> [SQLITE_OPEN_MAIN_JOURNAL]
622** <li> [SQLITE_OPEN_TEMP_DB]
623** <li> [SQLITE_OPEN_TEMP_JOURNAL]
624** <li> [SQLITE_OPEN_TRANSIENT_DB]
625** <li> [SQLITE_OPEN_SUBJOURNAL]
626** <li> [SQLITE_OPEN_MASTER_JOURNAL]
627** </ul>
628**
629** The file I/O implementation can use the object type flags to
630** changes the way it deals with files. For example, an application
631** that does not care about crash recovery or rollback, might make
632** the open of a journal file a no-op. Writes to this journal are
633** also a no-op. Any attempt to read the journal return SQLITE_IOERR.
634** Or the implementation might recognize the a database file will
635** be doing page-aligned sector reads and writes in a random order
636** and set up its I/O subsystem accordingly.
637**
638** SQLite might also add one of the following flags to the xOpen
639** method:
640**
641** <ul>
642** <li> [SQLITE_OPEN_DELETEONCLOSE]
643** <li> [SQLITE_OPEN_EXCLUSIVE]
644** </ul>
645**
646** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
647** deleted when it is closed. This will always be set for TEMP
648** databases and journals and for subjournals. The
649** [SQLITE_OPEN_EXCLUSIVE] flag means the file should be opened
650** for exclusive access. This flag is set for all files except
651** for the main database file.
652**
653** Space to hold the [sqlite3_file] structure passed as the third
654** argument to xOpen is allocated by caller (the SQLite core).
655** szOsFile bytes are allocated for this object. The xOpen method
656** fills in the allocated space.
657**
658** The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
659** to test for the existance of a file,
660** or [SQLITE_ACCESS_READWRITE] to test to see
661** if a file is readable and writable, or [SQLITE_ACCESS_READ]
662** to test to see if a file is at least readable. The file can be a
663** directory.
664**
665** SQLite will always allocate at least mxPathname+1 byte for
666** the output buffers for xGetTempname and xFullPathname. The exact
667** size of the output buffer is also passed as a parameter to both
668** methods. If the output buffer is not large enough, SQLITE_CANTOPEN
669** should be returned. As this is handled as a fatal error by SQLite,
670** vfs implementations should endevour to prevent this by setting
671** mxPathname to a sufficiently large value.
672**
673** The xRandomness(), xSleep(), and xCurrentTime() interfaces
674** are not strictly a part of the filesystem, but they are
675** included in the VFS structure for completeness.
676** The xRandomness() function attempts to return nBytes bytes
677** of good-quality randomness into zOut. The return value is
678** the actual number of bytes of randomness obtained. The
679** xSleep() method cause the calling thread to sleep for at
680** least the number of microseconds given. The xCurrentTime()
681** method returns a Julian Day Number for the current date and
682** time.
683*/
684typedef struct sqlite3_vfs sqlite3_vfs;
685struct sqlite3_vfs {
686 int iVersion; /* Structure version number */
687 int szOsFile; /* Size of subclassed sqlite3_file */
688 int mxPathname; /* Maximum file pathname length */
689 sqlite3_vfs *pNext; /* Next registered VFS */
690 const char *zName; /* Name of this virtual file system */
691 void *pAppData; /* Pointer to application-specific data */
692 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
693 int flags, int *pOutFlags);
694 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
695 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags);
696 int (*xGetTempname)(sqlite3_vfs*, int nOut, char *zOut);
697 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
698 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
699 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
700 void *(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol);
701 void (*xDlClose)(sqlite3_vfs*, void*);
702 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
703 int (*xSleep)(sqlite3_vfs*, int microseconds);
704 int (*xCurrentTime)(sqlite3_vfs*, double*);
705 /* New fields may be appended in figure versions. The iVersion
706 ** value will increment whenever this happens. */
707};
708
709/*
710** CAPI3REF: Flags for the xAccess VFS method
711**
712** These integer constants can be used as the third parameter to
713** the xAccess method of an [sqlite3_vfs] object. They determine
714** the kind of what kind of permissions the xAccess method is
715** looking for. With SQLITE_ACCESS_EXISTS, the xAccess method
716** simply checks to see if the file exists. With SQLITE_ACCESS_READWRITE,
717** the xAccess method checks to see if the file is both readable
718** and writable. With SQLITE_ACCESS_READ the xAccess method
719** checks to see if the file is readable.
720*/
721#define SQLITE_ACCESS_EXISTS 0
722#define SQLITE_ACCESS_READWRITE 1
723#define SQLITE_ACCESS_READ 2
724
725/*
726** CAPI3REF: Enable Or Disable Extended Result Codes
727**
728** This routine enables or disables the
729** [SQLITE_IOERR_READ | extended result codes] feature.
730** By default, SQLite API routines return one of only 26 integer
731** [SQLITE_OK | result codes]. When extended result codes
732** are enabled by this routine, the repetoire of result codes can be
733** much larger and can (hopefully) provide more detailed information
734** about the cause of an error.
735**
736** The second argument is a boolean value that turns extended result
737** codes on and off. Extended result codes are off by default for
738** backwards compatibility with older versions of SQLite.
739*/
740int sqlite3_extended_result_codes(sqlite3*, int onoff);
741
742/*
743** CAPI3REF: Last Insert Rowid
744**
745** Each entry in an SQLite table has a unique 64-bit signed integer key
746** called the "rowid". The rowid is always available as an undeclared
747** column named ROWID, OID, or _ROWID_. If the table has a column of
748** type INTEGER PRIMARY KEY then that column is another an alias for the
749** rowid.
750**
751** This routine returns the rowid of the most recent INSERT into
752** the database from the database connection given in the first
753** argument. If no inserts have ever occurred on this database
754** connection, zero is returned.
755**
756** If an INSERT occurs within a trigger, then the rowid of the
757** inserted row is returned by this routine as long as the trigger
758** is running. But once the trigger terminates, the value returned
759** by this routine reverts to the last value inserted before the
760** trigger fired.
761**
762** If another thread does a new insert on the same database connection
763** while this routine is running and thus changes the last insert rowid,
764** then the return value of this routine is undefined.
765*/
766sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
767
768/*
769** CAPI3REF: Count The Number Of Rows Modified
770**
771** This function returns the number of database rows that were changed
772** (or inserted or deleted) by the most recent SQL statement. Only
773** changes that are directly specified by the INSERT, UPDATE, or
774** DELETE statement are counted. Auxiliary changes caused by
775** triggers are not counted. Use the [sqlite3_total_changes()] function
776** to find the total number of changes including changes caused by triggers.
777**
778** Within the body of a trigger, the sqlite3_changes() interface can be
779** called to find the number of
780** changes in the most recently completed INSERT, UPDATE, or DELETE
781** statement within the body of the trigger.
782**
783** All changes are counted, even if they were later undone by a
784** ROLLBACK or ABORT. Except, changes associated with creating and
785** dropping tables are not counted.
786**
787** If a callback invokes [sqlite3_exec()] or [sqlite3_step()] recursively,
788** then the changes in the inner, recursive call are counted together
789** with the changes in the outer call.
790**
791** SQLite implements the command "DELETE FROM table" without a WHERE clause
792** by dropping and recreating the table. (This is much faster than going
793** through and deleting individual elements from the table.) Because of
794** this optimization, the change count for "DELETE FROM table" will be
795** zero regardless of the number of elements that were originally in the
796** table. To get an accurate count of the number of rows deleted, use
797** "DELETE FROM table WHERE 1" instead.
798**
799** If another thread makes changes on the same database connection
800** while this routine is running then the return value of this routine
801** is undefined.
802*/
803int sqlite3_changes(sqlite3*);
804
805/*
806** CAPI3REF: Total Number Of Rows Modified
807***
808** This function returns the number of database rows that have been
809** modified by INSERT, UPDATE or DELETE statements since the database handle
810** was opened. This includes UPDATE, INSERT and DELETE statements executed
811** as part of trigger programs. All changes are counted as soon as the
812** statement that makes them is completed (when the statement handle is
813** passed to [sqlite3_reset()] or [sqlite3_finalize()]).
814**
815** See also the [sqlite3_change()] interface.
816**
817** SQLite implements the command "DELETE FROM table" without a WHERE clause
818** by dropping and recreating the table. (This is much faster than going
819** through and deleting individual elements form the table.) Because of
820** this optimization, the change count for "DELETE FROM table" will be
821** zero regardless of the number of elements that were originally in the
822** table. To get an accurate count of the number of rows deleted, use
823** "DELETE FROM table WHERE 1" instead.
824**
825** If another thread makes changes on the same database connection
826** while this routine is running then the return value of this routine
827** is undefined.
828*/
829int sqlite3_total_changes(sqlite3*);
830
831/*
832** CAPI3REF: Interrupt A Long-Running Query
833**
834** This function causes any pending database operation to abort and
835** return at its earliest opportunity. This routine is typically
836** called in response to a user action such as pressing "Cancel"
837** or Ctrl-C where the user wants a long query operation to halt
838** immediately.
839**
840** It is safe to call this routine from a thread different from the
841** thread that is currently running the database operation. But it
842** is not safe to call this routine with a database connection that
843** is closed or might close before sqlite3_interrupt() returns.
844**
845** The SQL operation that is interrupted will return [SQLITE_INTERRUPT].
846** If an interrupted operation was an update that is inside an
847** explicit transaction, then the entire transaction will be rolled
848** back automatically.
849*/
850void sqlite3_interrupt(sqlite3*);
851
852/*
853** CAPI3REF: Determine If An SQL Statement Is Complete
854**
855** These functions return true if the given input string comprises
856** one or more complete SQL statements. For the sqlite3_complete() call,
857** the parameter must be a nul-terminated UTF-8 string. For
858** sqlite3_complete16(), a nul-terminated machine byte order UTF-16 string
859** is required.
860**
861** These routines are useful for command-line input to determine if the
862** currently entered text forms one or more complete SQL statements or
863** if additional input is needed before sending the statements into
864** SQLite for parsing. The algorithm is simple. If the
865** last token other than spaces and comments is a semicolon, then return
866** true. Actually, the algorithm is a little more complicated than that
867** in order to deal with triggers, but the basic idea is the same: the
868** statement is not complete unless it ends in a semicolon.
869*/
870int sqlite3_complete(const char *sql);
871int sqlite3_complete16(const void *sql);
872
873/*
874** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
875**
876** This routine identifies a callback function that might be invoked
877** whenever an attempt is made to open a database table
878** that another thread or process has locked.
879** If the busy callback is NULL, then [SQLITE_BUSY]
880** (or sometimes [SQLITE_IOERR_BLOCKED])
881** is returned immediately upon encountering the lock.
882** If the busy callback is not NULL, then the
883** callback will be invoked with two arguments. The
884** first argument to the handler is a copy of the void* pointer which
885** is the third argument to this routine. The second argument to
886** the handler is the number of times that the busy handler has
887** been invoked for this locking event. If the
888** busy callback returns 0, then no additional attempts are made to
889** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned.
890** If the callback returns non-zero, then another attempt is made to open the
891** database for reading and the cycle repeats.
892**
893** The presence of a busy handler does not guarantee that
894** it will be invoked when there is lock contention.
895** If SQLite determines that invoking the busy handler could result in
896** a deadlock, it will return [SQLITE_BUSY] instead.
897** Consider a scenario where one process is holding a read lock that
898** it is trying to promote to a reserved lock and
899** a second process is holding a reserved lock that it is trying
900** to promote to an exclusive lock. The first process cannot proceed
901** because it is blocked by the second and the second process cannot
902** proceed because it is blocked by the first. If both processes
903** invoke the busy handlers, neither will make any progress. Therefore,
904** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
905** will induce the first process to release its read lock and allow
906** the second process to proceed.
907**
908** The default busy callback is NULL.
909**
910** The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED] when
911** SQLite is in the middle of a large transaction where all the
912** changes will not fit into the in-memory cache. SQLite will
913** already hold a RESERVED lock on the database file, but it needs
914** to promote this lock to EXCLUSIVE so that it can spill cache
915** pages into the database file without harm to concurrent
916** readers. If it is unable to promote the lock, then the in-memory
917** cache will be left in an inconsistent state and so the error
918** code is promoted from the relatively benign [SQLITE_BUSY] to
919** the more severe [SQLITE_IOERR_BLOCKED]. This error code promotion
920** forces an automatic rollback of the changes. See the
921** <a href="http://www.sqlite.org/cvstrac/wiki?p=CorruptionFollowingBusyError">
922** CorruptionFollowingBusyError</a> wiki page for a discussion of why
923** this is important.
924**
925** Sqlite is re-entrant, so the busy handler may start a new query.
926** (It is not clear why anyone would every want to do this, but it
927** is allowed, in theory.) But the busy handler may not close the
928** database. Closing the database from a busy handler will delete
929** data structures out from under the executing query and will
930** probably result in a segmentation fault or other runtime error.
931**
932** There can only be a single busy handler defined for each database
933** connection. Setting a new busy handler clears any previous one.
934** Note that calling [sqlite3_busy_timeout()] will also set or clear
935** the busy handler.
936**
937** When operating in [sqlite3_enable_shared_cache | shared cache mode],
938** only a single busy handler can be defined for each database file.
939** So if two database connections share a single cache, then changing
940** the busy handler on one connection will also change the busy
941** handler in the other connection. The busy handler is invoked
942** in the thread that was running when the SQLITE_BUSY was hit.
943*/
944int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*);
945
946/*
947** CAPI3REF: Set A Busy Timeout
948**
949** This routine sets a busy handler that sleeps for a while when a
950** table is locked. The handler will sleep multiple times until
951** at least "ms" milliseconds of sleeping have been done. After
952** "ms" milliseconds of sleeping, the handler returns 0 which
953** causes [sqlite3_step()] to return [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED].
954**
955** Calling this routine with an argument less than or equal to zero
956** turns off all busy handlers.
957**
958** There can only be a single busy handler for a particular database
959** connection. If another busy handler was defined
960** (using [sqlite3_busy_handler()]) prior to calling
961** this routine, that other busy handler is cleared.
962*/
963int sqlite3_busy_timeout(sqlite3*, int ms);
964
965/*
966** CAPI3REF: Convenience Routines For Running Queries
967**
968** This next routine is a convenience wrapper around [sqlite3_exec()].
969** Instead of invoking a user-supplied callback for each row of the
970** result, this routine remembers each row of the result in memory
971** obtained from [sqlite3_malloc()], then returns all of the result after the
972** query has finished.
973**
974** As an example, suppose the query result where this table:
975**
976** <blockquote><pre>
977** Name | Age
978** -----------------------
979** Alice | 43
980** Bob | 28
981** Cindy | 21
982** </pre></blockquote>
983**
984** If the 3rd argument were &azResult then after the function returns
985** azResult will contain the following data:
986**
987** <blockquote><pre>
988** azResult&#91;0] = "Name";
989** azResult&#91;1] = "Age";
990** azResult&#91;2] = "Alice";
991** azResult&#91;3] = "43";
992** azResult&#91;4] = "Bob";
993** azResult&#91;5] = "28";
994** azResult&#91;6] = "Cindy";
995** azResult&#91;7] = "21";
996** </pre></blockquote>
997**
998** Notice that there is an extra row of data containing the column
999** headers. But the *nrow return value is still 3. *ncolumn is
1000** set to 2. In general, the number of values inserted into azResult
1001** will be ((*nrow) + 1)*(*ncolumn).
1002**
1003** After the calling function has finished using the result, it should
1004** pass the result data pointer to sqlite3_free_table() in order to
1005** release the memory that was malloc-ed. Because of the way the
1006** [sqlite3_malloc()] happens, the calling function must not try to call
1007** [sqlite3_free()] directly. Only [sqlite3_free_table()] is able to release
1008** the memory properly and safely.
1009**
1010** The return value of this routine is the same as from [sqlite3_exec()].
1011*/
1012int sqlite3_get_table(
1013 sqlite3*, /* An open database */
1014 const char *sql, /* SQL to be executed */
1015 char ***resultp, /* Result written to a char *[] that this points to */
1016 int *nrow, /* Number of result rows written here */
1017 int *ncolumn, /* Number of result columns written here */
1018 char **errmsg /* Error msg written here */
1019);
1020void sqlite3_free_table(char **result);
1021
1022/*
1023** CAPI3REF: Formatted String Printing Functions
1024**
1025** These routines are workalikes of the "printf()" family of functions
1026** from the standard C library.
1027**
1028** The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
1029** results into memory obtained from [sqlite3_malloc()].
1030** The strings returned by these two routines should be
1031** released by [sqlite3_free()]. Both routines return a
1032** NULL pointer if [sqlite3_malloc()] is unable to allocate enough
1033** memory to hold the resulting string.
1034**
1035** In sqlite3_snprintf() routine is similar to "snprintf()" from
1036** the standard C library. The result is written into the
1037** buffer supplied as the second parameter whose size is given by
1038** the first parameter. Note that the order of the
1039** first two parameters is reversed from snprintf(). This is an
1040** historical accident that cannot be fixed without breaking
1041** backwards compatibility. Note also that sqlite3_snprintf()
1042** returns a pointer to its buffer instead of the number of
1043** characters actually written into the buffer. We admit that
1044** the number of characters written would be a more useful return
1045** value but we cannot change the implementation of sqlite3_snprintf()
1046** now without breaking compatibility.
1047**
1048** As long as the buffer size is greater than zero, sqlite3_snprintf()
1049** guarantees that the buffer is always zero-terminated. The first
1050** parameter "n" is the total size of the buffer, including space for
1051** the zero terminator. So the longest string that can be completely
1052** written will be n-1 characters.
1053**
1054** These routines all implement some additional formatting
1055** options that are useful for constructing SQL statements.
1056** All of the usual printf formatting options apply. In addition, there
1057** is are "%q", "%Q", and "%z" options.
1058**
1059** The %q option works like %s in that it substitutes a null-terminated
1060** string from the argument list. But %q also doubles every '\'' character.
1061** %q is designed for use inside a string literal. By doubling each '\''
1062** character it escapes that character and allows it to be inserted into
1063** the string.
1064**
1065** For example, so some string variable contains text as follows:
1066**
1067** <blockquote><pre>
1068** char *zText = "It's a happy day!";
1069** </pre></blockquote>
1070**
1071** One can use this text in an SQL statement as follows:
1072**
1073** <blockquote><pre>
1074** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText);
1075** sqlite3_exec(db, zSQL, 0, 0, 0);
1076** sqlite3_free(zSQL);
1077** </pre></blockquote>
1078**
1079** Because the %q format string is used, the '\'' character in zText
1080** is escaped and the SQL generated is as follows:
1081**
1082** <blockquote><pre>
1083** INSERT INTO table1 VALUES('It''s a happy day!')
1084** </pre></blockquote>
1085**
1086** This is correct. Had we used %s instead of %q, the generated SQL
1087** would have looked like this:
1088**
1089** <blockquote><pre>
1090** INSERT INTO table1 VALUES('It's a happy day!');
1091** </pre></blockquote>
1092**
1093** This second example is an SQL syntax error. As a general rule you
1094** should always use %q instead of %s when inserting text into a string
1095** literal.
1096**
1097** The %Q option works like %q except it also adds single quotes around
1098** the outside of the total string. Or if the parameter in the argument
1099** list is a NULL pointer, %Q substitutes the text "NULL" (without single
1100** quotes) in place of the %Q option. So, for example, one could say:
1101**
1102** <blockquote><pre>
1103** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText);
1104** sqlite3_exec(db, zSQL, 0, 0, 0);
1105** sqlite3_free(zSQL);
1106** </pre></blockquote>
1107**
1108** The code above will render a correct SQL statement in the zSQL
1109** variable even if the zText variable is a NULL pointer.
1110**
1111** The "%z" formatting option works exactly like "%s" with the
1112** addition that after the string has been read and copied into
1113** the result, [sqlite3_free()] is called on the input string.
1114*/
1115char *sqlite3_mprintf(const char*,...);
1116char *sqlite3_vmprintf(const char*, va_list);
1117char *sqlite3_snprintf(int,char*,const char*, ...);
1118
1119/*
1120** CAPI3REF: Memory Allocation Subsystem
1121**
1122** The SQLite core uses these three routines for all of its own
1123** internal memory allocation needs. (See the exception below.)
1124** The default implementation
1125** of the memory allocation subsystem uses the malloc(), realloc()
1126** and free() provided by the standard C library. However, if
1127** SQLite is compiled with the following C preprocessor macro
1128**
1129** <blockquote> SQLITE_OMIT_MEMORY_ALLOCATION </blockquote>
1130**
1131** then no implementation is provided for these routines by
1132** SQLite. The application that links against SQLite is
1133** expected to provide its own implementation. If the application
1134** does provide its own implementation for these routines, then
1135** it must also provide an implementations for
1136** [sqlite3_memory_alarm()], [sqlite3_memory_used()], and
1137** [sqlite3_memory_highwater()]. The alternative implementations
1138** for these last three routines need not actually work, but
1139** stub functions at least are needed to statisfy the linker.
1140** SQLite never calls [sqlite3_memory_highwater()] itself, but
1141** the symbol is included in a table as part of the
1142** [sqlite3_load_extension()] interface. The
1143** [sqlite3_memory_alarm()] and [sqlite3_memory_used()] interfaces
1144** are called by [sqlite3_soft_heap_limit()] and working implementations
1145** of both routines must be provided if [sqlite3_soft_heap_limit()]
1146** is to operate correctly.
1147**
1148** <b>Exception:</b> The windows OS interface layer calls
1149** the system malloc() and free() directly when converting
1150** filenames between the UTF-8 encoding used by SQLite
1151** and whatever filename encoding is used by the particular windows
1152** installation. Memory allocation errors are detected, but
1153** they are reported back as [SQLITE_CANTOPEN] or
1154** [SQLITE_IOERR] rather than [SQLITE_NOMEM].
1155*/
1156void *sqlite3_malloc(int);
1157void *sqlite3_realloc(void*, int);
1158void sqlite3_free(void*);
1159
1160/*
1161** CAPI3REF: Memory Allocator Statistics
1162**
1163** In addition to the basic three allocation routines
1164** [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()],
1165** the memory allocation subsystem included with the SQLite
1166** sources provides the interfaces shown below.
1167**
1168** The first of these two routines returns the amount of memory
1169** currently outstanding (malloced but not freed). The second
1170** returns the largest instantaneous amount of outstanding
1171** memory. The highwater mark is reset if the argument is
1172** true.
1173**
1174** The implementation of these routines in the SQLite core
1175** is omitted if the application is compiled with the
1176** SQLITE_OMIT_MEMORY_ALLOCATION macro defined. In that case,
1177** the application that links SQLite must provide its own
1178** alternative implementation. See the documentation on
1179** [sqlite3_malloc()] for additional information.
1180*/
1181sqlite3_int64 sqlite3_memory_used(void);
1182sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
1183
1184/*
1185** CAPI3REF: Memory Allocation Alarms
1186**
1187** The [sqlite3_memory_alarm] routine is used to register
1188** a callback on memory allocation events.
1189**
1190** This routine registers or clears a callbacks that fires when
1191** the amount of memory allocated exceeds iThreshold. Only
1192** a single callback can be registered at a time. Each call
1193** to [sqlite3_memory_alarm()] overwrites the previous callback.
1194** The callback is disabled by setting xCallback to a NULL
1195** pointer.
1196**
1197** The parameters to the callback are the pArg value, the
1198** amount of memory currently in use, and the size of the
1199** allocation that provoked the callback. The callback will
1200** presumably invoke [sqlite3_free()] to free up memory space.
1201** The callback may invoke [sqlite3_malloc()] or [sqlite3_realloc()]
1202** but if it does, no additional callbacks will be invoked by
1203** the recursive calls.
1204**
1205** The [sqlite3_soft_heap_limit()] interface works by registering
1206** a memory alarm at the soft heap limit and invoking
1207** [sqlite3_release_memory()] in the alarm callback. Application
1208** programs should not attempt to use the [sqlite3_memory_alarm()]
1209** interface because doing so will interfere with the
1210** [sqlite3_soft_heap_limit()] module. This interface is exposed
1211** only so that applications can provide their own
1212** alternative implementation when the SQLite core is
1213** compiled with SQLITE_OMIT_MEMORY_ALLOCATION.
1214*/
1215int sqlite3_memory_alarm(
1216 void(*xCallback)(void *pArg, sqlite3_int64 used, int N),
1217 void *pArg,
1218 sqlite3_int64 iThreshold
1219);
1220
1221
1222/*
1223** CAPI3REF: Compile-Time Authorization Callbacks
1224***
1225** This routine registers a authorizer callback with the SQLite library.
1226** The authorizer callback is invoked as SQL statements are being compiled
1227** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
1228** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. At various
1229** points during the compilation process, as logic is being created
1230** to perform various actions, the authorizer callback is invoked to
1231** see if those actions are allowed. The authorizer callback should
1232** return SQLITE_OK to allow the action, [SQLITE_IGNORE] to disallow the
1233** specific action but allow the SQL statement to continue to be
1234** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
1235** rejected with an error.
1236**
1237** Depending on the action, the [SQLITE_IGNORE] and [SQLITE_DENY] return
1238** codes might mean something different or they might mean the same
1239** thing. If the action is, for example, to perform a delete opertion,
1240** then [SQLITE_IGNORE] and [SQLITE_DENY] both cause the statement compilation
1241** to fail with an error. But if the action is to read a specific column
1242** from a specific table, then [SQLITE_DENY] will cause the entire
1243** statement to fail but [SQLITE_IGNORE] will cause a NULL value to be
1244** read instead of the actual column value.
1245**
1246** The first parameter to the authorizer callback is a copy of
1247** the third parameter to the sqlite3_set_authorizer() interface.
1248** The second parameter to the callback is an integer
1249** [SQLITE_COPY | action code] that specifies the particular action
1250** to be authorized. The available action codes are
1251** [SQLITE_COPY | documented separately]. The third through sixth
1252** parameters to the callback are strings that contain additional
1253** details about the action to be authorized.
1254**
1255** An authorizer is used when preparing SQL statements from an untrusted
1256** source, to ensure that the SQL statements do not try to access data
1257** that they are not allowed to see, or that they do not try to
1258** execute malicious statements that damage the database. For
1259** example, an application may allow a user to enter arbitrary
1260** SQL queries for evaluation by a database. But the application does
1261** not want the user to be able to make arbitrary changes to the
1262** database. An authorizer could then be put in place while the
1263** user-entered SQL is being prepared that disallows everything
1264** except SELECT statements.
1265**
1266** Only a single authorizer can be in place on a database connection
1267** at a time. Each call to sqlite3_set_authorizer overrides the
1268** previous call. A NULL authorizer means that no authorization
1269** callback is invoked. The default authorizer is NULL.
1270**
1271** Note that the authorizer callback is invoked only during
1272** [sqlite3_prepare()] or its variants. Authorization is not
1273** performed during statement evaluation in [sqlite3_step()].
1274*/
1275int sqlite3_set_authorizer(
1276 sqlite3*,
1277 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
1278 void *pUserData
1279);
1280
1281/*
1282** CAPI3REF: Authorizer Return Codes
1283**
1284** The [sqlite3_set_authorizer | authorizer callback function] must
1285** return either [SQLITE_OK] or one of these two constants in order
1286** to signal SQLite whether or not the action is permitted. See the
1287** [sqlite3_set_authorizer | authorizer documentation] for additional
1288** information.
1289*/
1290#define SQLITE_DENY 1 /* Abort the SQL statement with an error */
1291#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */
1292
1293/*
1294** CAPI3REF: Authorizer Action Codes
1295**
1296** The [sqlite3_set_authorizer()] interface registers a callback function
1297** that is invoked to authorizer certain SQL statement actions. The
1298** second parameter to the callback is an integer code that specifies
1299** what action is being authorized. These are the integer action codes that
1300** the authorizer callback may be passed.
1301**
1302** These action code values signify what kind of operation is to be
1303** authorized. The 3rd and 4th parameters to the authorization callback
1304** function will be parameters or NULL depending on which of these
1305** codes is used as the second parameter. The 5th parameter to the
1306** authorizer callback is the name of the database ("main", "temp",
1307** etc.) if applicable. The 6th parameter to the authorizer callback
1308** is the name of the inner-most trigger or view that is responsible for
1309** the access attempt or NULL if this access attempt is directly from
1310** top-level SQL code.
1311*/
1312/******************************************* 3rd ************ 4th ***********/
1313#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */
1314#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */
1315#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */
1316#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */
1317#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */
1318#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */
1319#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */
1320#define SQLITE_CREATE_VIEW 8 /* View Name NULL */
1321#define SQLITE_DELETE 9 /* Table Name NULL */
1322#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */
1323#define SQLITE_DROP_TABLE 11 /* Table Name NULL */
1324#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */
1325#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */
1326#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */
1327#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */
1328#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */
1329#define SQLITE_DROP_VIEW 17 /* View Name NULL */
1330#define SQLITE_INSERT 18 /* Table Name NULL */
1331#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */
1332#define SQLITE_READ 20 /* Table Name Column Name */
1333#define SQLITE_SELECT 21 /* NULL NULL */
1334#define SQLITE_TRANSACTION 22 /* NULL NULL */
1335#define SQLITE_UPDATE 23 /* Table Name Column Name */
1336#define SQLITE_ATTACH 24 /* Filename NULL */
1337#define SQLITE_DETACH 25 /* Database Name NULL */
1338#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */
1339#define SQLITE_REINDEX 27 /* Index Name NULL */
1340#define SQLITE_ANALYZE 28 /* Table Name NULL */
1341#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */
1342#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */
1343#define SQLITE_FUNCTION 31 /* Function Name NULL */
1344#define SQLITE_COPY 0 /* No longer used */
1345
1346/*
1347** CAPI3REF: Tracing And Profiling Functions
1348**
1349** These routines register callback functions that can be used for
1350** tracing and profiling the execution of SQL statements.
1351** The callback function registered by sqlite3_trace() is invoked
1352** at the first [sqlite3_step()] for the evaluation of an SQL statement.
1353** The callback function registered by sqlite3_profile() is invoked
1354** as each SQL statement finishes and includes
1355** information on how long that statement ran.
1356**
1357** The sqlite3_profile() API is currently considered experimental and
1358** is subject to change.
1359*/
1360void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*);
1361void *sqlite3_profile(sqlite3*,
1362 void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
1363
1364/*
1365** CAPI3REF: Query Progress Callbacks
1366**
1367** This routine configures a callback function - the progress callback - that
1368** is invoked periodically during long running calls to [sqlite3_exec()],
1369** [sqlite3_step()] and [sqlite3_get_table()]. An example use for this
1370** interface is to keep a GUI updated during a large query.
1371**
1372** The progress callback is invoked once for every N virtual machine opcodes,
1373** where N is the second argument to this function. The progress callback
1374** itself is identified by the third argument to this function. The fourth
1375** argument to this function is a void pointer passed to the progress callback
1376** function each time it is invoked.
1377**
1378** If a call to [sqlite3_exec()], [sqlite3_step()], or [sqlite3_get_table()]
1379** results in fewer than N opcodes being executed, then the progress
1380** callback is never invoked.
1381**
1382** Only a single progress callback function may be registered for each
1383** open database connection. Every call to sqlite3_progress_handler()
1384** overwrites the results of the previous call.
1385** To remove the progress callback altogether, pass NULL as the third
1386** argument to this function.
1387**
1388** If the progress callback returns a result other than 0, then the current
1389** query is immediately terminated and any database changes rolled back.
1390** The containing [sqlite3_exec()], [sqlite3_step()], or
1391** [sqlite3_get_table()] call returns SQLITE_INTERRUPT. This feature
1392** can be used, for example, to implement the "Cancel" button on a
1393** progress dialog box in a GUI.
1394*/
1395void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
1396
1397/*
1398** CAPI3REF: Opening A New Database Connection
1399**
1400** Open the sqlite database file "filename". The "filename" is UTF-8
1401** encoded for [sqlite3_open()] and [sqlite3_open_v2()] and UTF-16 encoded
1402** in the native byte order for [sqlite3_open16()].
1403** An [sqlite3*] handle is returned in *ppDb, even
1404** if an error occurs. If the database is opened (or created) successfully,
1405** then [SQLITE_OK] is returned. Otherwise an error code is returned. The
1406** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
1407** an English language description of the error.
1408**
1409** The default encoding for the database will be UTF-8 if
1410** [sqlite3_open()] or [sqlite3_open_v2()] is called and
1411** UTF-16 if [sqlite3_open16()] is used.
1412**
1413** Whether or not an error occurs when it is opened, resources associated
1414** with the [sqlite3*] handle should be released by passing it to
1415** [sqlite3_close()] when it is no longer required.
1416**
1417** The [sqlite3_open_v2()] interface works like [sqlite3_open()] except that
1418** provides two additional parameters for additional control over the
1419** new database connection. The flags parameter can be one of:
1420**
1421** <ol>
1422** <li> [SQLITE_OPEN_READONLY]
1423** <li> [SQLITE_OPEN_READWRITE]
1424** <li> [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]
1425** </ol>
1426**
1427** The first value opens the database read-only. If the database does
1428** not previously exist, an error is returned. The second option opens
1429** the database for reading and writing if possible, or reading only if
1430** if the file is write protected. In either case the database must already
1431** exist or an error is returned. The third option opens the database
1432** for reading and writing and creates it if it does not already exist.
1433** The third options is behavior that is always used for [sqlite3_open()]
1434** and [sqlite3_open16()].
1435**
1436** If the filename is ":memory:", then an private
1437** in-memory database is created for the connection. This in-memory
1438** database will vanish when the database connection is closed. Future
1439** version of SQLite might make use of additional special filenames
1440** that begin with the ":" character. It is recommended that
1441** when a database filename really does begin with
1442** ":" that you prefix the filename with a pathname like "./" to
1443** avoid ambiguity.
1444**
1445** If the filename is an empty string, then a private temporary
1446** on-disk database will be created. This private database will be
1447** automatically deleted as soon as the database connection is closed.
1448**
1449** The fourth parameter to sqlite3_open_v2() is the name of the
1450** [sqlite3_vfs] object that defines the operating system
1451** interface that the new database connection should use. If the
1452** fourth parameter is a NULL pointer then the default [sqlite3_vfs]
1453** object is used.
1454**
1455** <b>Note to windows users:</b> The encoding used for the filename argument
1456** of [sqlite3_open()] and [sqlite3_open_v2()] must be UTF-8, not whatever
1457** codepage is currently defined. Filenames containing international
1458** characters must be converted to UTF-8 prior to passing them into
1459** [sqlite3_open()] or [sqlite3_open_v2()].
1460*/
1461int sqlite3_open(
1462 const char *filename, /* Database filename (UTF-8) */
1463 sqlite3 **ppDb /* OUT: SQLite db handle */
1464);
1465int sqlite3_open16(
1466 const void *filename, /* Database filename (UTF-16) */
1467 sqlite3 **ppDb /* OUT: SQLite db handle */
1468);
1469int sqlite3_open_v2(
1470 const char *filename, /* Database filename (UTF-8) */
1471 sqlite3 **ppDb, /* OUT: SQLite db handle */
1472 int flags, /* Flags */
1473 const char *zVfs /* Name of VFS module to use */
1474);
1475
1476/*
1477** CAPI3REF: Error Codes And Messages
1478**
1479** The sqlite3_errcode() interface returns the numeric
1480** [SQLITE_OK | result code] or [SQLITE_IOERR_READ | extended result code]
1481** for the most recent failed sqlite3_* API call associated
1482** with [sqlite3] handle 'db'. If a prior API call failed but the
1483** most recent API call succeeded, the return value from sqlite3_errcode()
1484** is undefined.
1485**
1486** The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
1487** text that describes the error, as either UTF8 or UTF16 respectively.
1488** Memory to hold the error message string is managed internally. The
1489** string may be overwritten or deallocated by subsequent calls to SQLite
1490** interface functions.
1491**
1492** Calls to many sqlite3_* functions set the error code and string returned
1493** by [sqlite3_errcode()], [sqlite3_errmsg()], and [sqlite3_errmsg16()]
1494** (overwriting the previous values). Note that calls to [sqlite3_errcode()],
1495** [sqlite3_errmsg()], and [sqlite3_errmsg16()] themselves do not affect the
1496** results of future invocations. Calls to API routines that do not return
1497** an error code (example: [sqlite3_data_count()]) do not
1498** change the error code returned by this routine. Interfaces that are
1499** not associated with a specific database connection (examples:
1500** [sqlite3_mprintf()] or [sqlite3_enable_shared_cache()] do not change
1501** the return code.
1502**
1503** Assuming no other intervening sqlite3_* API calls are made, the error
1504** code returned by this function is associated with the same error as
1505** the strings returned by [sqlite3_errmsg()] and [sqlite3_errmsg16()].
1506*/
1507int sqlite3_errcode(sqlite3 *db);
1508const char *sqlite3_errmsg(sqlite3*);
1509const void *sqlite3_errmsg16(sqlite3*);
1510
1511/*
1512** CAPI3REF: SQL Statement Object
1513**
1514** Instance of this object represent single SQL statements. This
1515** is variously known as a "prepared statement" or a
1516** "compiled SQL statement" or simply as a "statement".
1517**
1518** The life of a statement object goes something like this:
1519**
1520** <ol>
1521** <li> Create the object using [sqlite3_prepare_v2()] or a related
1522** function.
1523** <li> Bind values to host parameters using
1524** [sqlite3_bind_blob | sqlite3_bind_* interfaces].
1525** <li> Run the SQL by calling [sqlite3_step()] one or more times.
1526** <li> Reset the statement using [sqlite3_reset()] then go back
1527** to step 2. Do this zero or more times.
1528** <li> Destroy the object using [sqlite3_finalize()].
1529** </ol>
1530**
1531** Refer to documentation on individual methods above for additional
1532** information.
1533*/
1534typedef struct sqlite3_stmt sqlite3_stmt;
1535
1536/*
1537** CAPI3REF: Compiling An SQL Statement
1538**
1539** To execute an SQL query, it must first be compiled into a byte-code
1540** program using one of these routines.
1541**
1542** The first argument "db" is an [sqlite3 | SQLite database handle]
1543** obtained from a prior call to [sqlite3_open()], [sqlite3_open_v2()]
1544** or [sqlite3_open16()].
1545** The second argument "zSql" is the statement to be compiled, encoded
1546** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2()
1547** interfaces uses UTF-8 and sqlite3_prepare16() and sqlite3_prepare16_v2()
1548** use UTF-16.
1549**
1550** If the nByte argument is less
1551** than zero, then zSql is read up to the first zero terminator. If
1552** nByte is non-negative, then it is the maximum number of
1553** bytes read from zSql. When nByte is non-negative, the
1554** zSql string ends at either the first '\000' character or
1555** until the nByte-th byte, whichever comes first.
1556**
1557** *pzTail is made to point to the first byte past the end of the first
1558** SQL statement in zSql. This routine only compiles the first statement
1559** in zSql, so *pzTail is left pointing to what remains uncompiled.
1560**
1561** *ppStmt is left pointing to a compiled
1562** [sqlite3_stmt | SQL statement structure] that can be
1563** executed using [sqlite3_step()]. Or if there is an error, *ppStmt may be
1564** set to NULL. If the input text contained no SQL (if the input is and
1565** empty string or a comment) then *ppStmt is set to NULL. The calling
1566** procedure is responsible for deleting the compiled SQL statement
1567** using [sqlite3_finalize()] after it has finished with it.
1568**
1569** On success, [SQLITE_OK] is returned. Otherwise an
1570** [SQLITE_ERROR | error code] is returned.
1571**
1572** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are
1573** recommended for all new programs. The two older interfaces are retained
1574** for backwards compatibility, but their use is discouraged.
1575** In the "v2" interfaces, the prepared statement
1576** that is returned (the [sqlite3_stmt] object) contains a copy of the
1577** original SQL text. This causes the [sqlite3_step()] interface to
1578** behave a differently in two ways:
1579**
1580** <ol>
1581** <li>
1582** If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
1583** always used to do, [sqlite3_step()] will automatically recompile the SQL
1584** statement and try to run it again. If the schema has changed in a way
1585** that makes the statement no longer valid, [sqlite3_step()] will still
1586** return [SQLITE_SCHEMA]. But unlike the legacy behavior, [SQLITE_SCHEMA] is
1587** now a fatal error. Calling [sqlite3_prepare_v2()] again will not make the
1588** error go away. Note: use [sqlite3_errmsg()] to find the text of the parsing
1589** error that results in an [SQLITE_SCHEMA] return.
1590** </li>
1591**
1592** <li>
1593** When an error occurs,
1594** [sqlite3_step()] will return one of the detailed
1595** [SQLITE_ERROR | result codes] or
1596** [SQLITE_IOERR_READ | extended result codes] such as directly.
1597** The legacy behavior was that [sqlite3_step()] would only return a generic
1598** [SQLITE_ERROR] result code and you would have to make a second call to
1599** [sqlite3_reset()] in order to find the underlying cause of the problem.
1600** With the "v2" prepare interfaces, the underlying reason for the error is
1601** returned immediately.
1602** </li>
1603** </ol>
1604*/
1605int sqlite3_prepare(
1606 sqlite3 *db, /* Database handle */
1607 const char *zSql, /* SQL statement, UTF-8 encoded */
1608 int nByte, /* Maximum length of zSql in bytes. */
1609 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
1610 const char **pzTail /* OUT: Pointer to unused portion of zSql */
1611);
1612int sqlite3_prepare_v2(
1613 sqlite3 *db, /* Database handle */
1614 const char *zSql, /* SQL statement, UTF-8 encoded */
1615 int nByte, /* Maximum length of zSql in bytes. */
1616 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
1617 const char **pzTail /* OUT: Pointer to unused portion of zSql */
1618);
1619int sqlite3_prepare16(
1620 sqlite3 *db, /* Database handle */
1621 const void *zSql, /* SQL statement, UTF-16 encoded */
1622 int nByte, /* Maximum length of zSql in bytes. */
1623 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
1624 const void **pzTail /* OUT: Pointer to unused portion of zSql */
1625);
1626int sqlite3_prepare16_v2(
1627 sqlite3 *db, /* Database handle */
1628 const void *zSql, /* SQL statement, UTF-16 encoded */
1629 int nByte, /* Maximum length of zSql in bytes. */
1630 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
1631 const void **pzTail /* OUT: Pointer to unused portion of zSql */
1632);
1633
1634/*
1635** CAPI3REF: Dynamically Typed Value Object
1636**
1637** SQLite uses dynamic typing for the values it stores. Values can
1638** be integers, floating point values, strings, BLOBs, or NULL. When
1639** passing around values internally, each value is represented as
1640** an instance of the sqlite3_value object.
1641*/
1642typedef struct Mem sqlite3_value;
1643
1644/*
1645** CAPI3REF: SQL Function Context Object
1646**
1647** The context in which an SQL function executes is stored in an
1648** sqlite3_context object. A pointer to such an object is the
1649** first parameter to user-defined SQL functions.
1650*/
1651typedef struct sqlite3_context sqlite3_context;
1652
1653/*
1654** CAPI3REF: Binding Values To Prepared Statements
1655**
1656** In the SQL strings input to [sqlite3_prepare_v2()] and its variants,
1657** one or more literals can be replace by a parameter in one of these
1658** forms:
1659**
1660** <ul>
1661** <li> ?
1662** <li> ?NNN
1663** <li> :AAA
1664** <li> @AAA
1665** <li> $VVV
1666** </ul>
1667**
1668** In the parameter forms shown above NNN is an integer literal,
1669** AAA is an alphanumeric identifier and VVV is a variable name according
1670** to the syntax rules of the TCL programming language.
1671** The values of these parameters (also called "host parameter names")
1672** can be set using the sqlite3_bind_*() routines defined here.
1673**
1674** The first argument to the sqlite3_bind_*() routines always is a pointer
1675** to the [sqlite3_stmt] object returned from [sqlite3_prepare_v2()] or
1676** its variants. The second
1677** argument is the index of the parameter to be set. The first parameter has
1678** an index of 1. When the same named parameter is used more than once, second
1679** and subsequent
1680** occurrences have the same index as the first occurrence. The index for
1681** named parameters can be looked up using the
1682** [sqlite3_bind_parameter_name()] API if desired. The index for "?NNN"
1683** parametes is the value of NNN.
1684** The NNN value must be between 1 and the compile-time
1685** parameter SQLITE_MAX_VARIABLE_NUMBER (default value: 999).
1686** See <a href="limits.html">limits.html</a> for additional information.
1687**
1688** The third argument is the value to bind to the parameter.
1689**
1690** In those
1691** routines that have a fourth argument, its value is the number of bytes
1692** in the parameter. To be clear: the value is the number of bytes in the
1693** string, not the number of characters. The number
1694** of bytes does not include the zero-terminator at the end of strings.
1695** If the fourth parameter is negative, the length of the string is
1696** number of bytes up to the first zero terminator.
1697**
1698** The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and
1699** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or
1700** text after SQLite has finished with it. If the fifth argument is the
1701** special value [SQLITE_STATIC], then the library assumes that the information
1702** is in static, unmanaged space and does not need to be freed. If the
1703** fifth argument has the value [SQLITE_TRANSIENT], then SQLite makes its
1704** own private copy of the data immediately, before the sqlite3_bind_*()
1705** routine returns.
1706**
1707** The sqlite3_bind_zeroblob() routine binds a BLOB of length n that
1708** is filled with zeros. A zeroblob uses a fixed amount of memory
1709** (just an integer to hold it size) while it is being processed.
1710** Zeroblobs are intended to serve as place-holders for BLOBs whose
1711** content is later written using
1712** [sqlite3_blob_open | increment BLOB I/O] routines. A negative
1713** value for the zeroblob results in a zero-length BLOB.
1714**
1715** The sqlite3_bind_*() routines must be called after
1716** [sqlite3_prepare_v2()] (and its variants) or [sqlite3_reset()] and
1717** before [sqlite3_step()].
1718** Bindings are not cleared by the [sqlite3_reset()] routine.
1719** Unbound parameters are interpreted as NULL.
1720**
1721** These routines return [SQLITE_OK] on success or an error code if
1722** anything goes wrong. [SQLITE_RANGE] is returned if the parameter
1723** index is out of range. [SQLITE_NOMEM] is returned if malloc fails.
1724** [SQLITE_MISUSE] is returned if these routines are called on a virtual
1725** machine that is the wrong state or which has already been finalized.
1726*/
1727int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
1728int sqlite3_bind_double(sqlite3_stmt*, int, double);
1729int sqlite3_bind_int(sqlite3_stmt*, int, int);
1730int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
1731int sqlite3_bind_null(sqlite3_stmt*, int);
1732int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*));
1733int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
1734int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
1735int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
1736
1737/*
1738** CAPI3REF: Number Of Host Parameters
1739**
1740** Return the largest host parameter index in the precompiled statement given
1741** as the argument. When the host parameters are of the forms like ":AAA"
1742** or "?", then they are assigned sequential increasing numbers beginning
1743** with one, so the value returned is the number of parameters. However
1744** if the same host parameter name is used multiple times, each occurrance
1745** is given the same number, so the value returned in that case is the number
1746** of unique host parameter names. If host parameters of the form "?NNN"
1747** are used (where NNN is an integer) then there might be gaps in the
1748** numbering and the value returned by this interface is the index of the
1749** host parameter with the largest index value.
1750**
1751** The prepared statement must not be [sqlite3_finalize | finalized]
1752** prior to this routine returnning. Otherwise the results are undefined
1753** and probably undesirable.
1754*/
1755int sqlite3_bind_parameter_count(sqlite3_stmt*);
1756
1757/*
1758** CAPI3REF: Name Of A Host Parameter
1759**
1760** This routine returns a pointer to the name of the n-th parameter in a
1761** [sqlite3_stmt | prepared statement].
1762** Host parameters of the form ":AAA" or "@AAA" or "$VVV" have a name
1763** which is the string ":AAA" or "@AAA" or "$VVV".
1764** In other words, the initial ":" or "$" or "@"
1765** is included as part of the name.
1766** Parameters of the form "?" or "?NNN" have no name.
1767**
1768** The first bound parameter has an index of 1, not 0.
1769**
1770** If the value n is out of range or if the n-th parameter is nameless,
1771** then NULL is returned. The returned string is always in the
1772** UTF-8 encoding even if the named parameter was originally specified
1773** as UTF-16 in [sqlite3_prepare16()] or [sqlite3_prepare16_v2()].
1774*/
1775const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
1776
1777/*
1778** CAPI3REF: Index Of A Parameter With A Given Name
1779**
1780** This routine returns the index of a host parameter with the given name.
1781** The name must match exactly. If no parameter with the given name is
1782** found, return 0. Parameter names must be UTF8.
1783*/
1784int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
1785
1786/*
1787** CAPI3REF: Reset All Bindings On A Prepared Statement
1788**
1789** Contrary to the intuition of many, [sqlite3_reset()] does not
1790** reset the [sqlite3_bind_blob | bindings] on a
1791** [sqlite3_stmt | prepared statement]. Use this routine to
1792** reset all host parameters to NULL.
1793*/
1794int sqlite3_clear_bindings(sqlite3_stmt*);
1795
1796/*
1797** CAPI3REF: Number Of Columns In A Result Set
1798**
1799** Return the number of columns in the result set returned by the
1800** [sqlite3_stmt | compiled SQL statement]. This routine returns 0
1801** if pStmt is an SQL statement that does not return data (for
1802** example an UPDATE).
1803*/
1804int sqlite3_column_count(sqlite3_stmt *pStmt);
1805
1806/*
1807** CAPI3REF: Column Names In A Result Set
1808**
1809** These routines return the name assigned to a particular column
1810** in the result set of a SELECT statement. The sqlite3_column_name()
1811** interface returns a pointer to a UTF8 string and sqlite3_column_name16()
1812** returns a pointer to a UTF16 string. The first parameter is the
1813** [sqlite3_stmt | prepared statement] that implements the SELECT statement.
1814** The second parameter is the column number. The left-most column is
1815** number 0.
1816**
1817** The returned string pointer is valid until either the
1818** [sqlite3_stmt | prepared statement] is destroyed by [sqlite3_finalize()]
1819** or until the next call sqlite3_column_name() or sqlite3_column_name16()
1820** on the same column.
1821**
1822** If sqlite3_malloc() fails during the processing of either routine
1823** (for example during a conversion from UTF-8 to UTF-16) then a
1824** NULL pointer is returned.
1825*/
1826const char *sqlite3_column_name(sqlite3_stmt*, int N);
1827const void *sqlite3_column_name16(sqlite3_stmt*, int N);
1828
1829/*
1830** CAPI3REF: Source Of Data In A Query Result
1831**
1832** These routines provide a means to determine what column of what
1833** table in which database a result of a SELECT statement comes from.
1834** The name of the database or table or column can be returned as
1835** either a UTF8 or UTF16 string. The _database_ routines return
1836** the database name, the _table_ routines return the table name, and
1837** the origin_ routines return the column name.
1838** The returned string is valid until
1839** the [sqlite3_stmt | prepared statement] is destroyed using
1840** [sqlite3_finalize()] or until the same information is requested
1841** again in a different encoding.
1842**
1843** The names returned are the original un-aliased names of the
1844** database, table, and column.
1845**
1846** The first argument to the following calls is a
1847** [sqlite3_stmt | compiled SQL statement].
1848** These functions return information about the Nth column returned by
1849** the statement, where N is the second function argument.
1850**
1851** If the Nth column returned by the statement is an expression
1852** or subquery and is not a column value, then all of these functions
1853** return NULL. Otherwise, they return the
1854** name of the attached database, table and column that query result
1855** column was extracted from.
1856**
1857** As with all other SQLite APIs, those postfixed with "16" return UTF-16
1858** encoded strings, the other functions return UTF-8.
1859**
1860** These APIs are only available if the library was compiled with the
1861** SQLITE_ENABLE_COLUMN_METADATA preprocessor symbol defined.
1862**
1863** If two or more threads call one or more of these routines against the same
1864** prepared statement and column at the same time then the results are
1865** undefined.
1866*/
1867const char *sqlite3_column_database_name(sqlite3_stmt*,int);
1868const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
1869const char *sqlite3_column_table_name(sqlite3_stmt*,int);
1870const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
1871const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
1872const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
1873
1874/*
1875** CAPI3REF: Declared Datatype Of A Query Result
1876**
1877** The first parameter is a [sqlite3_stmt | compiled SQL statement].
1878** If this statement is a SELECT statement and the Nth column of the
1879** returned result set of that SELECT is a table column (not an
1880** expression or subquery) then the declared type of the table
1881** column is returned. If the Nth column of the result set is an
1882** expression or subquery, then a NULL pointer is returned.
1883** The returned string is always UTF-8 encoded. For example, in
1884** the database schema:
1885**
1886** CREATE TABLE t1(c1 VARIANT);
1887**
1888** And the following statement compiled:
1889**
1890** SELECT c1 + 1, c1 FROM t1;
1891**
1892** Then this routine would return the string "VARIANT" for the second
1893** result column (i==1), and a NULL pointer for the first result column
1894** (i==0).
1895**
1896** SQLite uses dynamic run-time typing. So just because a column
1897** is declared to contain a particular type does not mean that the
1898** data stored in that column is of the declared type. SQLite is
1899** strongly typed, but the typing is dynamic not static. Type
1900** is associated with individual values, not with the containers
1901** used to hold those values.
1902*/
1903const char *sqlite3_column_decltype(sqlite3_stmt *, int i);
1904const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
1905
1906/*
1907** CAPI3REF: Evaluate An SQL Statement
1908**
1909** After an [sqlite3_stmt | SQL statement] has been prepared with a call
1910** to either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or to one of
1911** the legacy interfaces [sqlite3_prepare()] or [sqlite3_prepare16()],
1912** then this function must be called one or more times to evaluate the
1913** statement.
1914**
1915** The details of the behavior of this sqlite3_step() interface depend
1916** on whether the statement was prepared using the newer "v2" interface
1917** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy
1918** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the
1919** new "v2" interface is recommended for new applications but the legacy
1920** interface will continue to be supported.
1921**
1922** In the lagacy interface, the return value will be either [SQLITE_BUSY],
1923** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
1924** With the "v2" interface, any of the other [SQLITE_OK | result code]
1925** or [SQLITE_IOERR_READ | extended result code] might be returned as
1926** well.
1927**
1928** [SQLITE_BUSY] means that the database engine was unable to acquire the
1929** database locks it needs to do its job. If the statement is a COMMIT
1930** or occurs outside of an explicit transaction, then you can retry the
1931** statement. If the statement is not a COMMIT and occurs within a
1932** explicit transaction then you should rollback the transaction before
1933** continuing.
1934**
1935** [SQLITE_DONE] means that the statement has finished executing
1936** successfully. sqlite3_step() should not be called again on this virtual
1937** machine without first calling [sqlite3_reset()] to reset the virtual
1938** machine back to its initial state.
1939**
1940** If the SQL statement being executed returns any data, then
1941** [SQLITE_ROW] is returned each time a new row of data is ready
1942** for processing by the caller. The values may be accessed using
1943** the [sqlite3_column_int | column access functions].
1944** sqlite3_step() is called again to retrieve the next row of data.
1945**
1946** [SQLITE_ERROR] means that a run-time error (such as a constraint
1947** violation) has occurred. sqlite3_step() should not be called again on
1948** the VM. More information may be found by calling [sqlite3_errmsg()].
1949** With the legacy interface, a more specific error code (example:
1950** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
1951** can be obtained by calling [sqlite3_reset()] on the
1952** [sqlite3_stmt | prepared statement]. In the "v2" interface,
1953** the more specific error code is returned directly by sqlite3_step().
1954**
1955** [SQLITE_MISUSE] means that the this routine was called inappropriately.
1956** Perhaps it was called on a [sqlite3_stmt | prepared statement] that has
1957** already been [sqlite3_finalize | finalized] or on one that had
1958** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could
1959** be the case that the same database connection is being used by two or
1960** more threads at the same moment in time.
1961**
1962** <b>Goofy Interface Alert:</b>
1963** In the legacy interface,
1964** the sqlite3_step() API always returns a generic error code,
1965** [SQLITE_ERROR], following any error other than [SQLITE_BUSY]
1966** and [SQLITE_MISUSE]. You must call [sqlite3_reset()] or
1967** [sqlite3_finalize()] in order to find one of the specific
1968** [SQLITE_ERROR | result codes] that better describes the error.
1969** We admit that this is a goofy design. The problem has been fixed
1970** with the "v2" interface. If you prepare all of your SQL statements
1971** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead
1972** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()], then the
1973** more specific [SQLITE_ERROR | result codes] are returned directly
1974** by sqlite3_step(). The use of the "v2" interface is recommended.
1975*/
1976int sqlite3_step(sqlite3_stmt*);
1977
1978/*
1979** CAPI3REF:
1980**
1981** Return the number of values in the current row of the result set.
1982**
1983** After a call to [sqlite3_step()] that returns [SQLITE_ROW], this routine
1984** will return the same value as the [sqlite3_column_count()] function.
1985** After [sqlite3_step()] has returned an [SQLITE_DONE], [SQLITE_BUSY], or
1986** a [SQLITE_ERROR | error code], or before [sqlite3_step()] has been
1987** called on the [sqlite3_stmt | prepared statement] for the first time,
1988** this routine returns zero.
1989*/
1990int sqlite3_data_count(sqlite3_stmt *pStmt);
1991
1992/*
1993** CAPI3REF: Fundamental Datatypes
1994**
1995** Every value in SQLite has one of five fundamental datatypes:
1996**
1997** <ul>
1998** <li> 64-bit signed integer
1999** <li> 64-bit IEEE floating point number
2000** <li> string
2001** <li> BLOB
2002** <li> NULL
2003** </ul>
2004**
2005** These constants are codes for each of those types.
2006**
2007** Note that the SQLITE_TEXT constant was also used in SQLite version 2
2008** for a completely different meaning. Software that links against both
2009** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT not
2010** SQLITE_TEXT.
2011*/
2012#define SQLITE_INTEGER 1
2013#define SQLITE_FLOAT 2
2014#define SQLITE_BLOB 4
2015#define SQLITE_NULL 5
2016#ifdef SQLITE_TEXT
2017# undef SQLITE_TEXT
2018#else
2019# define SQLITE_TEXT 3
2020#endif
2021#define SQLITE3_TEXT 3
2022
2023/*
2024** CAPI3REF: Results Values From A Query
2025**
2026** These routines return information about
2027** a single column of the current result row of a query. In every
2028** case the first argument is a pointer to the
2029** [sqlite3_stmt | SQL statement] that is being
2030** evaluated (the [sqlite3_stmt*] that was returned from
2031** [sqlite3_prepare_v2()] or one of its variants) and
2032** the second argument is the index of the column for which information
2033** should be returned. The left-most column of the result set
2034** has an index of 0.
2035**
2036** If the SQL statement is not currently point to a valid row, or if the
2037** the column index is out of range, the result is undefined.
2038** These routines may only be called when the most recent call to
2039** [sqlite3_step()] has returned [SQLITE_ROW] and neither
2040** [sqlite3_reset()] nor [sqlite3_finalize()] has been call subsequently.
2041** If any of these routines are called after [sqlite3_reset()] or
2042** [sqlite3_finalize()] or after [sqlite3_step()] has returned
2043** something other than [SQLITE_ROW], the results are undefined.
2044** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
2045** are called from a different thread while any of these routines
2046** are pending, then the results are undefined.
2047**
2048** The sqlite3_column_type() routine returns
2049** [SQLITE_INTEGER | datatype code] for the initial data type
2050** of the result column. The returned value is one of [SQLITE_INTEGER],
2051** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value
2052** returned by sqlite3_column_type() is only meaningful if no type
2053** conversions have occurred as described below. After a type conversion,
2054** the value returned by sqlite3_column_type() is undefined. Future
2055** versions of SQLite may change the behavior of sqlite3_column_type()
2056** following a type conversion.
2057**
2058** If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
2059** routine returns the number of bytes in that BLOB or string.
2060** If the result is a UTF-16 string, then sqlite3_column_bytes() converts
2061** the string to UTF-8 and then returns the number of bytes.
2062** If the result is a numeric value then sqlite3_column_bytes() uses
2063** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
2064** the number of bytes in that string.
2065** The value returned does not include the zero terminator at the end
2066** of the string. For clarity: the value returned is the number of
2067** bytes in the string, not the number of characters.
2068**
2069** Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
2070** even zero-length strings, are always zero terminated. The return
2071** value from sqlite3_column_blob() for a zero-length blob is an arbitrary
2072** pointer, possibly even a NULL pointer.
2073**
2074** The sqlite3_column_bytes16() routine is similar to sqlite3_column_bytes()
2075** but leaves the result in UTF-16 instead of UTF-8.
2076** The zero terminator is not included in this count.
2077**
2078** These routines attempt to convert the value where appropriate. For
2079** example, if the internal representation is FLOAT and a text result
2080** is requested, [sqlite3_snprintf()] is used internally to do the conversion
2081** automatically. The following table details the conversions that
2082** are applied:
2083**
2084** <blockquote>
2085** <table border="1">
2086** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion
2087**
2088** <tr><td> NULL <td> INTEGER <td> Result is 0
2089** <tr><td> NULL <td> FLOAT <td> Result is 0.0
2090** <tr><td> NULL <td> TEXT <td> Result is NULL pointer
2091** <tr><td> NULL <td> BLOB <td> Result is NULL pointer
2092** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float
2093** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer
2094** <tr><td> INTEGER <td> BLOB <td> Same as for INTEGER->TEXT
2095** <tr><td> FLOAT <td> INTEGER <td> Convert from float to integer
2096** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float
2097** <tr><td> FLOAT <td> BLOB <td> Same as FLOAT->TEXT
2098** <tr><td> TEXT <td> INTEGER <td> Use atoi()
2099** <tr><td> TEXT <td> FLOAT <td> Use atof()
2100** <tr><td> TEXT <td> BLOB <td> No change
2101** <tr><td> BLOB <td> INTEGER <td> Convert to TEXT then use atoi()
2102** <tr><td> BLOB <td> FLOAT <td> Convert to TEXT then use atof()
2103** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed
2104** </table>
2105** </blockquote>
2106**
2107** The table above makes reference to standard C library functions atoi()
2108** and atof(). SQLite does not really use these functions. It has its
2109** on equavalent internal routines. The atoi() and atof() names are
2110** used in the table for brevity and because they are familiar to most
2111** C programmers.
2112**
2113** Note that when type conversions occur, pointers returned by prior
2114** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
2115** sqlite3_column_text16() may be invalidated.
2116** Type conversions and pointer invalidations might occur
2117** in the following cases:
2118**
2119** <ul>
2120** <li><p> The initial content is a BLOB and sqlite3_column_text()
2121** or sqlite3_column_text16() is called. A zero-terminator might
2122** need to be added to the string.</p></li>
2123**
2124** <li><p> The initial content is UTF-8 text and sqlite3_column_bytes16() or
2125** sqlite3_column_text16() is called. The content must be converted
2126** to UTF-16.</p></li>
2127**
2128** <li><p> The initial content is UTF-16 text and sqlite3_column_bytes() or
2129** sqlite3_column_text() is called. The content must be converted
2130** to UTF-8.</p></li>
2131** </ul>
2132**
2133** Conversions between UTF-16be and UTF-16le are always done in place and do
2134** not invalidate a prior pointer, though of course the content of the buffer
2135** that the prior pointer points to will have been modified. Other kinds
2136** of conversion are done in place when it is possible, but sometime it is
2137** not possible and in those cases prior pointers are invalidated.
2138**
2139** The safest and easiest to remember policy is to invoke these routines
2140** in one of the following ways:
2141**
2142** <ul>
2143** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
2144** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
2145** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
2146** </ul>
2147**
2148** In other words, you should call sqlite3_column_text(), sqlite3_column_blob(),
2149** or sqlite3_column_text16() first to force the result into the desired
2150** format, then invoke sqlite3_column_bytes() or sqlite3_column_bytes16() to
2151** find the size of the result. Do not mix call to sqlite3_column_text() or
2152** sqlite3_column_blob() with calls to sqlite3_column_bytes16(). And do not
2153** mix calls to sqlite3_column_text16() with calls to sqlite3_column_bytes().
2154**
2155** The pointers returned are valid until a type conversion occurs as
2156** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
2157** [sqlite3_finalize()] is called. The memory space used to hold strings
2158** and blobs is freed automatically. Do <b>not</b> pass the pointers returned
2159** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
2160** [sqlite3_free()].
2161**
2162** If a memory allocation error occurs during the evaluation of any
2163** of these routines, a default value is returned. The default value
2164** is either the integer 0, the floating point number 0.0, or a NULL
2165** pointer. Subsequent calls to [sqlite3_errcode()] will return
2166** [SQLITE_NOMEM].
2167*/
2168const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
2169int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
2170int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
2171double sqlite3_column_double(sqlite3_stmt*, int iCol);
2172int sqlite3_column_int(sqlite3_stmt*, int iCol);
2173sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
2174const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
2175const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
2176int sqlite3_column_type(sqlite3_stmt*, int iCol);
2177sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
2178
2179/*
2180** CAPI3REF: Destroy A Prepared Statement Object
2181**
2182** The sqlite3_finalize() function is called to delete a
2183** [sqlite3_stmt | compiled SQL statement]. If the statement was
2184** executed successfully, or not executed at all, then SQLITE_OK is returned.
2185** If execution of the statement failed then an
2186** [SQLITE_ERROR | error code] or [SQLITE_IOERR_READ | extended error code]
2187** is returned.
2188**
2189** This routine can be called at any point during the execution of the
2190** [sqlite3_stmt | virtual machine]. If the virtual machine has not
2191** completed execution when this routine is called, that is like
2192** encountering an error or an interrupt. (See [sqlite3_interrupt()].)
2193** Incomplete updates may be rolled back and transactions cancelled,
2194** depending on the circumstances, and the
2195** [SQLITE_ERROR | result code] returned will be [SQLITE_ABORT].
2196*/
2197int sqlite3_finalize(sqlite3_stmt *pStmt);
2198
2199/*
2200** CAPI3REF: Reset A Prepared Statement Object
2201**
2202** The sqlite3_reset() function is called to reset a
2203** [sqlite3_stmt | compiled SQL statement] object.
2204** back to it's initial state, ready to be re-executed.
2205** Any SQL statement variables that had values bound to them using
2206** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
2207** Use [sqlite3_clear_bindings()] to reset the bindings.
2208*/
2209int sqlite3_reset(sqlite3_stmt *pStmt);
2210
2211/*
2212** CAPI3REF: Create Or Redefine SQL Functions
2213**
2214** The following two functions are used to add SQL functions or aggregates
2215** or to redefine the behavior of existing SQL functions or aggregates. The
2216** difference only between the two is that the second parameter, the
2217** name of the (scalar) function or aggregate, is encoded in UTF-8 for
2218** sqlite3_create_function() and UTF-16 for sqlite3_create_function16().
2219**
2220** The first argument is the [sqlite3 | database handle] that holds the
2221** SQL function or aggregate is to be added or redefined. If a single
2222** program uses more than one database handle internally, then SQL
2223** functions or aggregates must be added individually to each database
2224** handle with which they will be used.
2225**
2226** The second parameter is the name of the SQL function to be created
2227** or redefined.
2228** The length of the name is limited to 255 bytes, exclusive of the
2229** zero-terminator. Note that the name length limit is in bytes, not
2230** characters. Any attempt to create a function with a longer name
2231** will result in an SQLITE_ERROR error.
2232**
2233** The third parameter is the number of arguments that the SQL function or
2234** aggregate takes. If this parameter is negative, then the SQL function or
2235** aggregate may take any number of arguments.
2236**
2237** The fourth parameter, eTextRep, specifies what
2238** [SQLITE_UTF8 | text encoding] this SQL function prefers for
2239** its parameters. Any SQL function implementation should be able to work
2240** work with UTF-8, UTF-16le, or UTF-16be. But some implementations may be
2241** more efficient with one encoding than another. It is allowed to
2242** invoke sqlite3_create_function() or sqlite3_create_function16() multiple
2243** times with the same function but with different values of eTextRep.
2244** When multiple implementations of the same function are available, SQLite
2245** will pick the one that involves the least amount of data conversion.
2246** If there is only a single implementation which does not care what
2247** text encoding is used, then the fourth argument should be
2248** [SQLITE_ANY].
2249**
2250** The fifth parameter is an arbitrary pointer. The implementation
2251** of the function can gain access to this pointer using
2252** [sqlite3_user_data()].
2253**
2254** The seventh, eighth and ninth parameters, xFunc, xStep and xFinal, are
2255** pointers to C-language functions that implement the SQL
2256** function or aggregate. A scalar SQL function requires an implementation of
2257** the xFunc callback only, NULL pointers should be passed as the xStep
2258** and xFinal parameters. An aggregate SQL function requires an implementation
2259** of xStep and xFinal and NULL should be passed for xFunc. To delete an
2260** existing SQL function or aggregate, pass NULL for all three function
2261** callback.
2262**
2263** It is permitted to register multiple implementations of the same
2264** functions with the same name but with either differing numbers of
2265** arguments or differing perferred text encodings. SQLite will use
2266** the implementation most closely matches the way in which the
2267** SQL function is used.
2268*/
2269int sqlite3_create_function(
2270 sqlite3 *,
2271 const char *zFunctionName,
2272 int nArg,
2273 int eTextRep,
2274 void*,
2275 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
2276 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
2277 void (*xFinal)(sqlite3_context*)
2278);
2279int sqlite3_create_function16(
2280 sqlite3*,
2281 const void *zFunctionName,
2282 int nArg,
2283 int eTextRep,
2284 void*,
2285 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
2286 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
2287 void (*xFinal)(sqlite3_context*)
2288);
2289
2290/*
2291** CAPI3REF: Text Encodings
2292**
2293** These constant define integer codes that represent the various
2294** text encodings supported by SQLite.
2295*/
2296#define SQLITE_UTF8 1
2297#define SQLITE_UTF16LE 2
2298#define SQLITE_UTF16BE 3
2299#define SQLITE_UTF16 4 /* Use native byte order */
2300#define SQLITE_ANY 5 /* sqlite3_create_function only */
2301#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */
2302
2303/*
2304** CAPI3REF: Obsolete Functions
2305**
2306** These functions are all now obsolete. In order to maintain
2307** backwards compatibility with older code, we continue to support
2308** these functions. However, new development projects should avoid
2309** the use of these functions. To help encourage people to avoid
2310** using these functions, we are not going to tell you want they do.
2311*/
2312int sqlite3_aggregate_count(sqlite3_context*);
2313int sqlite3_expired(sqlite3_stmt*);
2314int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
2315int sqlite3_global_recover(void);
2316void sqlite3_thread_cleanup(void);
2317
2318/*
2319** CAPI3REF: Obtaining SQL Function Parameter Values
2320**
2321** The C-language implementation of SQL functions and aggregates uses
2322** this set of interface routines to access the parameter values on
2323** the function or aggregate.
2324**
2325** The xFunc (for scalar functions) or xStep (for aggregates) parameters
2326** to [sqlite3_create_function()] and [sqlite3_create_function16()]
2327** define callbacks that implement the SQL functions and aggregates.
2328** The 4th parameter to these callbacks is an array of pointers to
2329** [sqlite3_value] objects. There is one [sqlite3_value] object for
2330** each parameter to the SQL function. These routines are used to
2331** extract values from the [sqlite3_value] objects.
2332**
2333** These routines work just like the corresponding
2334** [sqlite3_column_blob | sqlite3_column_* routines] except that
2335** these routines take a single [sqlite3_value*] pointer instead
2336** of an [sqlite3_stmt*] pointer and an integer column number.
2337**
2338** The sqlite3_value_text16() interface extracts a UTF16 string
2339** in the native byte-order of the host machine. The
2340** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
2341** extract UTF16 strings as big-endian and little-endian respectively.
2342**
2343** The sqlite3_value_numeric_type() interface attempts to apply
2344** numeric affinity to the value. This means that an attempt is
2345** made to convert the value to an integer or floating point. If
2346** such a conversion is possible without loss of information (in order
2347** words if the value is original a string that looks like a number)
2348** then it is done. Otherwise no conversion occurs. The
2349** [SQLITE_INTEGER | datatype] after conversion is returned.
2350**
2351** Please pay particular attention to the fact that the pointer that
2352** is returned from [sqlite3_value_blob()], [sqlite3_value_text()], or
2353** [sqlite3_value_text16()] can be invalidated by a subsequent call to
2354** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
2355** or [sqlite3_value_text16()].
2356**
2357** These routines must be called from the same thread as
2358** the SQL function that supplied the sqlite3_value* parameters.
2359** Or, if the sqlite3_value* argument comes from the [sqlite3_column_value()]
2360** interface, then these routines should be called from the same thread
2361** that ran [sqlite3_column_value()].
2362*/
2363const void *sqlite3_value_blob(sqlite3_value*);
2364int sqlite3_value_bytes(sqlite3_value*);
2365int sqlite3_value_bytes16(sqlite3_value*);
2366double sqlite3_value_double(sqlite3_value*);
2367int sqlite3_value_int(sqlite3_value*);
2368sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
2369const unsigned char *sqlite3_value_text(sqlite3_value*);
2370const void *sqlite3_value_text16(sqlite3_value*);
2371const void *sqlite3_value_text16le(sqlite3_value*);
2372const void *sqlite3_value_text16be(sqlite3_value*);
2373int sqlite3_value_type(sqlite3_value*);
2374int sqlite3_value_numeric_type(sqlite3_value*);
2375
2376/*
2377** CAPI3REF: Obtain Aggregate Function Context
2378**
2379** The implementation of aggregate SQL functions use this routine to allocate
2380** a structure for storing their state. The first time this routine
2381** is called for a particular aggregate, a new structure of size nBytes
2382** is allocated, zeroed, and returned. On subsequent calls (for the
2383** same aggregate instance) the same buffer is returned. The implementation
2384** of the aggregate can use the returned buffer to accumulate data.
2385**
2386** The buffer allocated is freed automatically by SQLite whan the aggregate
2387** query concludes.
2388**
2389** The first parameter should be a copy of the
2390** [sqlite3_context | SQL function context] that is the first
2391** parameter to the callback routine that implements the aggregate
2392** function.
2393**
2394** This routine must be called from the same thread in which
2395** the aggregate SQL function is running.
2396*/
2397void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
2398
2399/*
2400** CAPI3REF: User Data For Functions
2401**
2402** The pUserData parameter to the [sqlite3_create_function()]
2403** and [sqlite3_create_function16()] routines
2404** used to register user functions is available to
2405** the implementation of the function using this call.
2406**
2407** This routine must be called from the same thread in which
2408** the SQL function is running.
2409*/
2410void *sqlite3_user_data(sqlite3_context*);
2411
2412/*
2413** CAPI3REF: Function Auxiliary Data
2414**
2415** The following two functions may be used by scalar SQL functions to
2416** associate meta-data with argument values. If the same value is passed to
2417** multiple invocations of the same SQL function during query execution, under
2418** some circumstances the associated meta-data may be preserved. This may
2419** be used, for example, to add a regular-expression matching scalar
2420** function. The compiled version of the regular expression is stored as
2421** meta-data associated with the SQL value passed as the regular expression
2422** pattern. The compiled regular expression can be reused on multiple
2423** invocations of the same function so that the original pattern string
2424** does not need to be recompiled on each invocation.
2425**
2426** The sqlite3_get_auxdata() interface returns a pointer to the meta-data
2427** associated with the Nth argument value to the current SQL function
2428** call, where N is the second parameter. If no meta-data has been set for
2429** that value, then a NULL pointer is returned.
2430**
2431** The sqlite3_set_auxdata() is used to associate meta-data with an SQL
2432** function argument. The third parameter is a pointer to the meta-data
2433** to be associated with the Nth user function argument value. The fourth
2434** parameter specifies a destructor that will be called on the meta-
2435** data pointer to release it when it is no longer required. If the
2436** destructor is NULL, it is not invoked.
2437**
2438** In practice, meta-data is preserved between function calls for
2439** expressions that are constant at compile time. This includes literal
2440** values and SQL variables.
2441**
2442** These routines must be called from the same thread in which
2443** the SQL function is running.
2444*/
2445void *sqlite3_get_auxdata(sqlite3_context*, int);
2446void sqlite3_set_auxdata(sqlite3_context*, int, void*, void (*)(void*));
2447
2448
2449/*
2450** CAPI3REF: Constants Defining Special Destructor Behavior
2451**
2452** These are special value for the destructor that is passed in as the
2453** final argument to routines like [sqlite3_result_blob()]. If the destructor
2454** argument is SQLITE_STATIC, it means that the content pointer is constant
2455** and will never change. It does not need to be destroyed. The
2456** SQLITE_TRANSIENT value means that the content will likely change in
2457** the near future and that SQLite should make its own private copy of
2458** the content before returning.
2459**
2460** The typedef is necessary to work around problems in certain
2461** C++ compilers. See ticket #2191.
2462*/
2463typedef void (*sqlite3_destructor_type)(void*);
2464#define SQLITE_STATIC ((sqlite3_destructor_type)0)
2465#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1)
2466
2467/*
2468** CAPI3REF: Setting The Result Of An SQL Function
2469**
2470** These routines are used by the xFunc or xFinal callbacks that
2471** implement SQL functions and aggregates. See
2472** [sqlite3_create_function()] and [sqlite3_create_function16()]
2473** for additional information.
2474**
2475** These functions work very much like the
2476** [sqlite3_bind_blob | sqlite3_bind_*] family of functions used
2477** to bind values to host parameters in prepared statements.
2478** Refer to the
2479** [sqlite3_bind_blob | sqlite3_bind_* documentation] for
2480** additional information.
2481**
2482** The sqlite3_result_error() and sqlite3_result_error16() functions
2483** cause the implemented SQL function to throw an exception. The
2484** parameter to sqlite3_result_error() or sqlite3_result_error16()
2485** is the text of an error message.
2486**
2487** The sqlite3_result_toobig() cause the function implementation
2488** to throw and error indicating that a string or BLOB is to long
2489** to represent.
2490**
2491** These routines must be called from within the same thread as
2492** the SQL function associated with the [sqlite3_context] pointer.
2493*/
2494void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
2495void sqlite3_result_double(sqlite3_context*, double);
2496void sqlite3_result_error(sqlite3_context*, const char*, int);
2497void sqlite3_result_error16(sqlite3_context*, const void*, int);
2498void sqlite3_result_error_toobig(sqlite3_context*);
2499void sqlite3_result_error_nomem(sqlite3_context*);
2500void sqlite3_result_int(sqlite3_context*, int);
2501void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
2502void sqlite3_result_null(sqlite3_context*);
2503void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
2504void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
2505void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
2506void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
2507void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
2508void sqlite3_result_zeroblob(sqlite3_context*, int n);
2509
2510/*
2511** CAPI3REF: Define New Collating Sequences
2512**
2513** These functions are used to add new collation sequences to the
2514** [sqlite3*] handle specified as the first argument.
2515**
2516** The name of the new collation sequence is specified as a UTF-8 string
2517** for sqlite3_create_collation() and sqlite3_create_collation_v2()
2518** and a UTF-16 string for sqlite3_create_collation16(). In all cases
2519** the name is passed as the second function argument.
2520**
2521** The third argument must be one of the constants [SQLITE_UTF8],
2522** [SQLITE_UTF16LE] or [SQLITE_UTF16BE], indicating that the user-supplied
2523** routine expects to be passed pointers to strings encoded using UTF-8,
2524** UTF-16 little-endian or UTF-16 big-endian respectively.
2525**
2526** A pointer to the user supplied routine must be passed as the fifth
2527** argument. If it is NULL, this is the same as deleting the collation
2528** sequence (so that SQLite cannot call it anymore). Each time the user
2529** supplied function is invoked, it is passed a copy of the void* passed as
2530** the fourth argument to sqlite3_create_collation() or
2531** sqlite3_create_collation16() as its first parameter.
2532**
2533** The remaining arguments to the user-supplied routine are two strings,
2534** each represented by a [length, data] pair and encoded in the encoding
2535** that was passed as the third argument when the collation sequence was
2536** registered. The user routine should return negative, zero or positive if
2537** the first string is less than, equal to, or greater than the second
2538** string. i.e. (STRING1 - STRING2).
2539**
2540** The sqlite3_create_collation_v2() works like sqlite3_create_collation()
2541** excapt that it takes an extra argument which is a destructor for
2542** the collation. The destructor is called when the collation is
2543** destroyed and is passed a copy of the fourth parameter void* pointer
2544** of the sqlite3_create_collation_v2(). Collations are destroyed when
2545** they are overridden by later calls to the collation creation functions
2546** or when the [sqlite3*] database handle is closed using [sqlite3_close()].
2547**
2548** The sqlite3_create_collation_v2() interface is experimental and
2549** subject to change in future releases. The other collation creation
2550** functions are stable.
2551*/
2552int sqlite3_create_collation(
2553 sqlite3*,
2554 const char *zName,
2555 int eTextRep,
2556 void*,
2557 int(*xCompare)(void*,int,const void*,int,const void*)
2558);
2559int sqlite3_create_collation_v2(
2560 sqlite3*,
2561 const char *zName,
2562 int eTextRep,
2563 void*,
2564 int(*xCompare)(void*,int,const void*,int,const void*),
2565 void(*xDestroy)(void*)
2566);
2567int sqlite3_create_collation16(
2568 sqlite3*,
2569 const char *zName,
2570 int eTextRep,
2571 void*,
2572 int(*xCompare)(void*,int,const void*,int,const void*)
2573);
2574
2575/*
2576** CAPI3REF: Collation Needed Callbacks
2577**
2578** To avoid having to register all collation sequences before a database
2579** can be used, a single callback function may be registered with the
2580** database handle to be called whenever an undefined collation sequence is
2581** required.
2582**
2583** If the function is registered using the sqlite3_collation_needed() API,
2584** then it is passed the names of undefined collation sequences as strings
2585** encoded in UTF-8. If sqlite3_collation_needed16() is used, the names
2586** are passed as UTF-16 in machine native byte order. A call to either
2587** function replaces any existing callback.
2588**
2589** When the callback is invoked, the first argument passed is a copy
2590** of the second argument to sqlite3_collation_needed() or
2591** sqlite3_collation_needed16(). The second argument is the database
2592** handle. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], or
2593** [SQLITE_UTF16LE], indicating the most desirable form of the collation
2594** sequence function required. The fourth parameter is the name of the
2595** required collation sequence.
2596**
2597** The callback function should register the desired collation using
2598** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
2599** [sqlite3_create_collation_v2()].
2600*/
2601int sqlite3_collation_needed(
2602 sqlite3*,
2603 void*,
2604 void(*)(void*,sqlite3*,int eTextRep,const char*)
2605);
2606int sqlite3_collation_needed16(
2607 sqlite3*,
2608 void*,
2609 void(*)(void*,sqlite3*,int eTextRep,const void*)
2610);
2611
2612/*
2613** Specify the key for an encrypted database. This routine should be
2614** called right after sqlite3_open().
2615**
2616** The code to implement this API is not available in the public release
2617** of SQLite.
2618*/
2619int sqlite3_key(
2620 sqlite3 *db, /* Database to be rekeyed */
2621 const void *pKey, int nKey /* The key */
2622);
2623
2624/*
2625** Change the key on an open database. If the current database is not
2626** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the
2627** database is decrypted.
2628**
2629** The code to implement this API is not available in the public release
2630** of SQLite.
2631*/
2632int sqlite3_rekey(
2633 sqlite3 *db, /* Database to be rekeyed */
2634 const void *pKey, int nKey /* The new key */
2635);
2636
2637/*
2638** CAPI3REF: Suspend Execution For A Short Time
2639**
2640** This function causes the current thread to suspend execution
2641** a number of milliseconds specified in its parameter.
2642**
2643** If the operating system does not support sleep requests with
2644** millisecond time resolution, then the time will be rounded up to
2645** the nearest second. The number of milliseconds of sleep actually
2646** requested from the operating system is returned.
2647**
2648** SQLite implements this interface by calling the xSleep()
2649** method of the default [sqlite3_vfs] object.
2650*/
2651int sqlite3_sleep(int);
2652
2653/*
2654** CAPI3REF: Name Of The Folder Holding Temporary Files
2655**
2656** If this global variable is made to point to a string which is
2657** the name of a folder (a.ka. directory), then all temporary files
2658** created by SQLite will be placed in that directory. If this variable
2659** is NULL pointer, then SQLite does a search for an appropriate temporary
2660** file directory.
2661**
2662** It is not safe to modify this variable once a database connection
2663** has been opened. It is intended that this variable be set once
2664** as part of process initialization and before any SQLite interface
2665** routines have been call and remain unchanged thereafter.
2666*/
2667SQLITE_EXTERN char *sqlite3_temp_directory;
2668
2669/*
2670** CAPI3REF: Test To See If The Database Is In Auto-Commit Mode
2671**
2672** Test to see whether or not the database connection is in autocommit
2673** mode. Return TRUE if it is and FALSE if not. Autocommit mode is on
2674** by default. Autocommit is disabled by a BEGIN statement and reenabled
2675** by the next COMMIT or ROLLBACK.
2676**
2677** If certain kinds of errors occur on a statement within a multi-statement
2678** transactions (errors including [SQLITE_FULL], [SQLITE_IOERR],
2679** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
2680** transaction might be rolled back automatically. The only way to
2681** find out if SQLite automatically rolled back the transaction after
2682** an error is to use this function.
2683**
2684** If another thread changes the autocommit status of the database
2685** connection while this routine is running, then the return value
2686** is undefined.
2687*/
2688int sqlite3_get_autocommit(sqlite3*);
2689
2690/*
2691** CAPI3REF: Find The Database Handle Associated With A Prepared Statement
2692**
2693** Return the [sqlite3*] database handle to which a
2694** [sqlite3_stmt | prepared statement] belongs.
2695** This is the same database handle that was
2696** the first argument to the [sqlite3_prepare_v2()] or its variants
2697** that was used to create the statement in the first place.
2698*/
2699sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
2700
2701
2702/*
2703** CAPI3REF: Commit And Rollback Notification Callbacks
2704**
2705** These routines
2706** register callback functions to be invoked whenever a transaction
2707** is committed or rolled back. The pArg argument is passed through
2708** to the callback. If the callback on a commit hook function
2709** returns non-zero, then the commit is converted into a rollback.
2710**
2711** If another function was previously registered, its pArg value is returned.
2712** Otherwise NULL is returned.
2713**
2714** Registering a NULL function disables the callback.
2715**
2716** For the purposes of this API, a transaction is said to have been
2717** rolled back if an explicit "ROLLBACK" statement is executed, or
2718** an error or constraint causes an implicit rollback to occur. The
2719** callback is not invoked if a transaction is automatically rolled
2720** back because the database connection is closed.
2721**
2722** These are experimental interfaces and are subject to change.
2723*/
2724void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
2725void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
2726
2727/*
2728** CAPI3REF: Data Change Notification Callbacks
2729**
2730** Register a callback function with the database connection identified by the
2731** first argument to be invoked whenever a row is updated, inserted or deleted.
2732** Any callback set by a previous call to this function for the same
2733** database connection is overridden.
2734**
2735** The second argument is a pointer to the function to invoke when a
2736** row is updated, inserted or deleted. The first argument to the callback is
2737** a copy of the third argument to sqlite3_update_hook(). The second callback
2738** argument is one of SQLITE_INSERT, SQLITE_DELETE or SQLITE_UPDATE, depending
2739** on the operation that caused the callback to be invoked. The third and
2740** fourth arguments to the callback contain pointers to the database and
2741** table name containing the affected row. The final callback parameter is
2742** the rowid of the row. In the case of an update, this is the rowid after
2743** the update takes place.
2744**
2745** The update hook is not invoked when internal system tables are
2746** modified (i.e. sqlite_master and sqlite_sequence).
2747**
2748** If another function was previously registered, its pArg value is returned.
2749** Otherwise NULL is returned.
2750*/
2751void *sqlite3_update_hook(
2752 sqlite3*,
2753 void(*)(void *,int ,char const *,char const *,sqlite3_int64),
2754 void*
2755);
2756
2757/*
2758** CAPI3REF: Enable Or Disable Shared Pager Cache
2759**
2760** This routine enables or disables the sharing of the database cache
2761** and schema data structures between connections to the same database.
2762** Sharing is enabled if the argument is true and disabled if the argument
2763** is false.
2764**
2765** Beginning in SQLite version 3.5.0, cache sharing is enabled and disabled
2766** for an entire process. In prior versions of SQLite, sharing was
2767** enabled or disabled for each thread separately.
2768**
2769** The cache sharing mode set by this interface effects all subsequent
2770** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
2771** Existing database connections continue use the sharing mode that was
2772** in effect at the time they were opened.
2773**
2774** Virtual tables cannot be used with a shared cache. When shared
2775** cache is enabled, the [sqlite3_create_module()] API used to register
2776** virtual tables will always return an error.
2777**
2778** This routine returns [SQLITE_OK] if shared cache was
2779** enabled or disabled successfully. An [SQLITE_ERROR | error code]
2780** is returned otherwise.
2781**
2782** Shared cache is disabled by default. But this might change in
2783** future releases of SQLite. Applications that care about shared
2784** cache setting should set it explicitly.
2785*/
2786int sqlite3_enable_shared_cache(int);
2787
2788/*
2789** CAPI3REF: Attempt To Free Heap Memory
2790**
2791** Attempt to free N bytes of heap memory by deallocating non-essential
2792** memory allocations held by the database library (example: memory
2793** used to cache database pages to improve performance).
2794*/
2795int sqlite3_release_memory(int);
2796
2797/*
2798** CAPI3REF: Impose A Limit On Heap Size
2799**
2800** Place a "soft" limit on the amount of heap memory that may be allocated
2801** by SQLite. If an internal allocation is requested
2802** that would exceed the specified limit, [sqlite3_release_memory()] is
2803** invoked one or more times to free up some space before the allocation
2804** is made.
2805**
2806** The limit is called "soft", because if [sqlite3_release_memory()] cannot
2807** free sufficient memory to prevent the limit from being exceeded,
2808** the memory is allocated anyway and the current operation proceeds.
2809**
2810** A negative or zero value for N means that there is no soft heap limit and
2811** [sqlite3_release_memory()] will only be called when memory is exhausted.
2812** The default value for the soft heap limit is zero.
2813**
2814** SQLite makes a best effort to honor the soft heap limit. But if it
2815** is unable to reduce memory usage below the soft limit, execution will
2816** continue without error or notification. This is why the limit is
2817** called a "soft" limit. It is advisory only.
2818**
2819** The soft heap limit is implemented using the [sqlite3_memory_alarm()]
2820** interface. Only a single memory alarm is available in the default
2821** implementation. This means that if the application also uses the
2822** memory alarm interface it will interfere with the operation of the
2823** soft heap limit and undefined behavior will result.
2824**
2825** Prior to SQLite version 3.5.0, this routine only constrained the memory
2826** allocated by a single thread - the same thread in which this routine
2827** runs. Beginning with SQLite version 3.5.0, the soft heap limit is
2828** applied to all threads. The value specified for the soft heap limit
2829** is an upper bound on the total memory allocation for all threads. In
2830** version 3.5.0 there is no mechanism for limiting the heap usage for
2831** individual threads.
2832*/
2833void sqlite3_soft_heap_limit(int);
2834
2835/*
2836** CAPI3REF: Extract Metadata About A Column Of A Table
2837**
2838** This routine
2839** returns meta-data about a specific column of a specific database
2840** table accessible using the connection handle passed as the first function
2841** argument.
2842**
2843** The column is identified by the second, third and fourth parameters to
2844** this function. The second parameter is either the name of the database
2845** (i.e. "main", "temp" or an attached database) containing the specified
2846** table or NULL. If it is NULL, then all attached databases are searched
2847** for the table using the same algorithm as the database engine uses to
2848** resolve unqualified table references.
2849**
2850** The third and fourth parameters to this function are the table and column
2851** name of the desired column, respectively. Neither of these parameters
2852** may be NULL.
2853**
2854** Meta information is returned by writing to the memory locations passed as
2855** the 5th and subsequent parameters to this function. Any of these
2856** arguments may be NULL, in which case the corresponding element of meta
2857** information is ommitted.
2858**
2859** <pre>
2860** Parameter Output Type Description
2861** -----------------------------------
2862**
2863** 5th const char* Data type
2864** 6th const char* Name of the default collation sequence
2865** 7th int True if the column has a NOT NULL constraint
2866** 8th int True if the column is part of the PRIMARY KEY
2867** 9th int True if the column is AUTOINCREMENT
2868** </pre>
2869**
2870**
2871** The memory pointed to by the character pointers returned for the
2872** declaration type and collation sequence is valid only until the next
2873** call to any sqlite API function.
2874**
2875** If the specified table is actually a view, then an error is returned.
2876**
2877** If the specified column is "rowid", "oid" or "_rowid_" and an
2878** INTEGER PRIMARY KEY column has been explicitly declared, then the output
2879** parameters are set for the explicitly declared column. If there is no
2880** explicitly declared IPK column, then the output parameters are set as
2881** follows:
2882**
2883** <pre>
2884** data type: "INTEGER"
2885** collation sequence: "BINARY"
2886** not null: 0
2887** primary key: 1
2888** auto increment: 0
2889** </pre>
2890**
2891** This function may load one or more schemas from database files. If an
2892** error occurs during this process, or if the requested table or column
2893** cannot be found, an SQLITE error code is returned and an error message
2894** left in the database handle (to be retrieved using sqlite3_errmsg()).
2895**
2896** This API is only available if the library was compiled with the
2897** SQLITE_ENABLE_COLUMN_METADATA preprocessor symbol defined.
2898*/
2899int sqlite3_table_column_metadata(
2900 sqlite3 *db, /* Connection handle */
2901 const char *zDbName, /* Database name or NULL */
2902 const char *zTableName, /* Table name */
2903 const char *zColumnName, /* Column name */
2904 char const **pzDataType, /* OUTPUT: Declared data type */
2905 char const **pzCollSeq, /* OUTPUT: Collation sequence name */
2906 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */
2907 int *pPrimaryKey, /* OUTPUT: True if column part of PK */
2908 int *pAutoinc /* OUTPUT: True if column is auto-increment */
2909);
2910
2911/*
2912** CAPI3REF: Load An Extension
2913**
2914** Attempt to load an SQLite extension library contained in the file
2915** zFile. The entry point is zProc. zProc may be 0 in which case the
2916** name of the entry point defaults to "sqlite3_extension_init".
2917**
2918** Return [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
2919**
2920** If an error occurs and pzErrMsg is not 0, then fill *pzErrMsg with
2921** error message text. The calling function should free this memory
2922** by calling [sqlite3_free()].
2923**
2924** Extension loading must be enabled using [sqlite3_enable_load_extension()]
2925** prior to calling this API or an error will be returned.
2926*/
2927int sqlite3_load_extension(
2928 sqlite3 *db, /* Load the extension into this database connection */
2929 const char *zFile, /* Name of the shared library containing extension */
2930 const char *zProc, /* Entry point. Derived from zFile if 0 */
2931 char **pzErrMsg /* Put error message here if not 0 */
2932);
2933
2934/*
2935** CAPI3REF: Enable Or Disable Extension Loading
2936**
2937** So as not to open security holes in older applications that are
2938** unprepared to deal with extension loading, and as a means of disabling
2939** extension loading while evaluating user-entered SQL, the following
2940** API is provided to turn the [sqlite3_load_extension()] mechanism on and
2941** off. It is off by default. See ticket #1863.
2942**
2943** Call this routine with onoff==1 to turn extension loading on
2944** and call it with onoff==0 to turn it back off again.
2945*/
2946int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
2947
2948/*
2949** CAPI3REF: Make Arrangements To Automatically Load An Extension
2950**
2951** Register an extension entry point that is automatically invoked
2952** whenever a new database connection is opened using
2953** [sqlite3_open()], [sqlite3_open16()], or [sqlite3_open_v2()].
2954**
2955** This API can be invoked at program startup in order to register
2956** one or more statically linked extensions that will be available
2957** to all new database connections.
2958**
2959** Duplicate extensions are detected so calling this routine multiple
2960** times with the same extension is harmless.
2961**
2962** This routine stores a pointer to the extension in an array
2963** that is obtained from malloc(). If you run a memory leak
2964** checker on your program and it reports a leak because of this
2965** array, then invoke [sqlite3_automatic_extension_reset()] prior
2966** to shutdown to free the memory.
2967**
2968** Automatic extensions apply across all threads.
2969**
2970** This interface is experimental and is subject to change or
2971** removal in future releases of SQLite.
2972*/
2973int sqlite3_auto_extension(void *xEntryPoint);
2974
2975
2976/*
2977** CAPI3REF: Reset Automatic Extension Loading
2978**
2979** Disable all previously registered automatic extensions. This
2980** routine undoes the effect of all prior [sqlite3_automatic_extension()]
2981** calls.
2982**
2983** This call disabled automatic extensions in all threads.
2984**
2985** This interface is experimental and is subject to change or
2986** removal in future releases of SQLite.
2987*/
2988void sqlite3_reset_auto_extension(void);
2989
2990
2991/*
2992****** EXPERIMENTAL - subject to change without notice **************
2993**
2994** The interface to the virtual-table mechanism is currently considered
2995** to be experimental. The interface might change in incompatible ways.
2996** If this is a problem for you, do not use the interface at this time.
2997**
2998** When the virtual-table mechanism stablizes, we will declare the
2999** interface fixed, support it indefinitely, and remove this comment.
3000*/
3001
3002/*
3003** Structures used by the virtual table interface
3004*/
3005typedef struct sqlite3_vtab sqlite3_vtab;
3006typedef struct sqlite3_index_info sqlite3_index_info;
3007typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
3008typedef struct sqlite3_module sqlite3_module;
3009
3010/*
3011** A module is a class of virtual tables. Each module is defined
3012** by an instance of the following structure. This structure consists
3013** mostly of methods for the module.
3014*/
3015struct sqlite3_module {
3016 int iVersion;
3017 int (*xCreate)(sqlite3*, void *pAux,
3018 int argc, const char *const*argv,
3019 sqlite3_vtab **ppVTab, char**);
3020 int (*xConnect)(sqlite3*, void *pAux,
3021 int argc, const char *const*argv,
3022 sqlite3_vtab **ppVTab, char**);
3023 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
3024 int (*xDisconnect)(sqlite3_vtab *pVTab);
3025 int (*xDestroy)(sqlite3_vtab *pVTab);
3026 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
3027 int (*xClose)(sqlite3_vtab_cursor*);
3028 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
3029 int argc, sqlite3_value **argv);
3030 int (*xNext)(sqlite3_vtab_cursor*);
3031 int (*xEof)(sqlite3_vtab_cursor*);
3032 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
3033 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
3034 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
3035 int (*xBegin)(sqlite3_vtab *pVTab);
3036 int (*xSync)(sqlite3_vtab *pVTab);
3037 int (*xCommit)(sqlite3_vtab *pVTab);
3038 int (*xRollback)(sqlite3_vtab *pVTab);
3039 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
3040 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
3041 void **ppArg);
3042
3043 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
3044};
3045
3046/*
3047** The sqlite3_index_info structure and its substructures is used to
3048** pass information into and receive the reply from the xBestIndex
3049** method of an sqlite3_module. The fields under **Inputs** are the
3050** inputs to xBestIndex and are read-only. xBestIndex inserts its
3051** results into the **Outputs** fields.
3052**
3053** The aConstraint[] array records WHERE clause constraints of the
3054** form:
3055**
3056** column OP expr
3057**
3058** Where OP is =, <, <=, >, or >=. The particular operator is stored
3059** in aConstraint[].op. The index of the column is stored in
3060** aConstraint[].iColumn. aConstraint[].usable is TRUE if the
3061** expr on the right-hand side can be evaluated (and thus the constraint
3062** is usable) and false if it cannot.
3063**
3064** The optimizer automatically inverts terms of the form "expr OP column"
3065** and makes other simplifications to the WHERE clause in an attempt to
3066** get as many WHERE clause terms into the form shown above as possible.
3067** The aConstraint[] array only reports WHERE clause terms in the correct
3068** form that refer to the particular virtual table being queried.
3069**
3070** Information about the ORDER BY clause is stored in aOrderBy[].
3071** Each term of aOrderBy records a column of the ORDER BY clause.
3072**
3073** The xBestIndex method must fill aConstraintUsage[] with information
3074** about what parameters to pass to xFilter. If argvIndex>0 then
3075** the right-hand side of the corresponding aConstraint[] is evaluated
3076** and becomes the argvIndex-th entry in argv. If aConstraintUsage[].omit
3077** is true, then the constraint is assumed to be fully handled by the
3078** virtual table and is not checked again by SQLite.
3079**
3080** The idxNum and idxPtr values are recorded and passed into xFilter.
3081** sqlite3_free() is used to free idxPtr if needToFreeIdxPtr is true.
3082**
3083** The orderByConsumed means that output from xFilter will occur in
3084** the correct order to satisfy the ORDER BY clause so that no separate
3085** sorting step is required.
3086**
3087** The estimatedCost value is an estimate of the cost of doing the
3088** particular lookup. A full scan of a table with N entries should have
3089** a cost of N. A binary search of a table of N entries should have a
3090** cost of approximately log(N).
3091*/
3092struct sqlite3_index_info {
3093 /* Inputs */
3094 int nConstraint; /* Number of entries in aConstraint */
3095 struct sqlite3_index_constraint {
3096 int iColumn; /* Column on left-hand side of constraint */
3097 unsigned char op; /* Constraint operator */
3098 unsigned char usable; /* True if this constraint is usable */
3099 int iTermOffset; /* Used internally - xBestIndex should ignore */
3100 } *aConstraint; /* Table of WHERE clause constraints */
3101 int nOrderBy; /* Number of terms in the ORDER BY clause */
3102 struct sqlite3_index_orderby {
3103 int iColumn; /* Column number */
3104 unsigned char desc; /* True for DESC. False for ASC. */
3105 } *aOrderBy; /* The ORDER BY clause */
3106
3107 /* Outputs */
3108 struct sqlite3_index_constraint_usage {
3109 int argvIndex; /* if >0, constraint is part of argv to xFilter */
3110 unsigned char omit; /* Do not code a test for this constraint */
3111 } *aConstraintUsage;
3112 int idxNum; /* Number used to identify the index */
3113 char *idxStr; /* String, possibly obtained from sqlite3_malloc */
3114 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */
3115 int orderByConsumed; /* True if output is already ordered */
3116 double estimatedCost; /* Estimated cost of using this index */
3117};
3118#define SQLITE_INDEX_CONSTRAINT_EQ 2
3119#define SQLITE_INDEX_CONSTRAINT_GT 4
3120#define SQLITE_INDEX_CONSTRAINT_LE 8
3121#define SQLITE_INDEX_CONSTRAINT_LT 16
3122#define SQLITE_INDEX_CONSTRAINT_GE 32
3123#define SQLITE_INDEX_CONSTRAINT_MATCH 64
3124
3125/*
3126** This routine is used to register a new module name with an SQLite
3127** connection. Module names must be registered before creating new
3128** virtual tables on the module, or before using preexisting virtual
3129** tables of the module.
3130*/
3131int sqlite3_create_module(
3132 sqlite3 *db, /* SQLite connection to register module with */
3133 const char *zName, /* Name of the module */
3134 const sqlite3_module *, /* Methods for the module */
3135 void * /* Client data for xCreate/xConnect */
3136);
3137
3138/*
3139** This routine is identical to the sqlite3_create_module() method above,
3140** except that it allows a destructor function to be specified. It is
3141** even more experimental than the rest of the virtual tables API.
3142*/
3143int sqlite3_create_module_v2(
3144 sqlite3 *db, /* SQLite connection to register module with */
3145 const char *zName, /* Name of the module */
3146 const sqlite3_module *, /* Methods for the module */
3147 void *, /* Client data for xCreate/xConnect */
3148 void(*xDestroy)(void*) /* Module destructor function */
3149);
3150
3151/*
3152** Every module implementation uses a subclass of the following structure
3153** to describe a particular instance of the module. Each subclass will
3154** be tailored to the specific needs of the module implementation. The
3155** purpose of this superclass is to define certain fields that are common
3156** to all module implementations.
3157**
3158** Virtual tables methods can set an error message by assigning a
3159** string obtained from sqlite3_mprintf() to zErrMsg. The method should
3160** take care that any prior string is freed by a call to sqlite3_free()
3161** prior to assigning a new string to zErrMsg. After the error message
3162** is delivered up to the client application, the string will be automatically
3163** freed by sqlite3_free() and the zErrMsg field will be zeroed. Note
3164** that sqlite3_mprintf() and sqlite3_free() are used on the zErrMsg field
3165** since virtual tables are commonly implemented in loadable extensions which
3166** do not have access to sqlite3MPrintf() or sqlite3Free().
3167*/
3168struct sqlite3_vtab {
3169 const sqlite3_module *pModule; /* The module for this virtual table */
3170 int nRef; /* Used internally */
3171 char *zErrMsg; /* Error message from sqlite3_mprintf() */
3172 /* Virtual table implementations will typically add additional fields */
3173};
3174
3175/* Every module implementation uses a subclass of the following structure
3176** to describe cursors that point into the virtual table and are used
3177** to loop through the virtual table. Cursors are created using the
3178** xOpen method of the module. Each module implementation will define
3179** the content of a cursor structure to suit its own needs.
3180**
3181** This superclass exists in order to define fields of the cursor that
3182** are common to all implementations.
3183*/
3184struct sqlite3_vtab_cursor {
3185 sqlite3_vtab *pVtab; /* Virtual table of this cursor */
3186 /* Virtual table implementations will typically add additional fields */
3187};
3188
3189/*
3190** The xCreate and xConnect methods of a module use the following API
3191** to declare the format (the names and datatypes of the columns) of
3192** the virtual tables they implement.
3193*/
3194int sqlite3_declare_vtab(sqlite3*, const char *zCreateTable);
3195
3196/*
3197** Virtual tables can provide alternative implementations of functions
3198** using the xFindFunction method. But global versions of those functions
3199** must exist in order to be overloaded.
3200**
3201** This API makes sure a global version of a function with a particular
3202** name and number of parameters exists. If no such function exists
3203** before this API is called, a new function is created. The implementation
3204** of the new function always causes an exception to be thrown. So
3205** the new function is not good for anything by itself. Its only
3206** purpose is to be a place-holder function that can be overloaded
3207** by virtual tables.
3208**
3209** This API should be considered part of the virtual table interface,
3210** which is experimental and subject to change.
3211*/
3212int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
3213
3214/*
3215** The interface to the virtual-table mechanism defined above (back up
3216** to a comment remarkably similar to this one) is currently considered
3217** to be experimental. The interface might change in incompatible ways.
3218** If this is a problem for you, do not use the interface at this time.
3219**
3220** When the virtual-table mechanism stabilizes, we will declare the
3221** interface fixed, support it indefinitely, and remove this comment.
3222**
3223****** EXPERIMENTAL - subject to change without notice **************
3224*/
3225
3226/*
3227** CAPI3REF: A Handle To An Open BLOB
3228**
3229** An instance of the following opaque structure is used to
3230** represent an blob-handle. A blob-handle is created by
3231** [sqlite3_blob_open()] and destroyed by [sqlite3_blob_close()].
3232** The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
3233** can be used to read or write small subsections of the blob.
3234** The [sqlite3_blob_bytes()] interface returns the size of the
3235** blob in bytes.
3236*/
3237typedef struct sqlite3_blob sqlite3_blob;
3238
3239/*
3240** CAPI3REF: Open A BLOB For Incremental I/O
3241**
3242** Open a handle to the blob located in row iRow,, column zColumn,
3243** table zTable in database zDb. i.e. the same blob that would
3244** be selected by:
3245**
3246** <pre>
3247** SELECT zColumn FROM zDb.zTable WHERE rowid = iRow;
3248** </pre>
3249**
3250** If the flags parameter is non-zero, the blob is opened for
3251** read and write access. If it is zero, the blob is opened for read
3252** access.
3253**
3254** On success, [SQLITE_OK] is returned and the new
3255** [sqlite3_blob | blob handle] is written to *ppBlob.
3256** Otherwise an error code is returned and
3257** any value written to *ppBlob should not be used by the caller.
3258** This function sets the database-handle error code and message
3259** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()].
3260*/
3261int sqlite3_blob_open(
3262 sqlite3*,
3263 const char *zDb,
3264 const char *zTable,
3265 const char *zColumn,
3266 sqlite3_int64 iRow,
3267 int flags,
3268 sqlite3_blob **ppBlob
3269);
3270
3271/*
3272** CAPI3REF: Close A BLOB Handle
3273**
3274** Close an open [sqlite3_blob | blob handle].
3275*/
3276int sqlite3_blob_close(sqlite3_blob *);
3277
3278/*
3279** CAPI3REF: Return The Size Of An Open BLOB
3280**
3281** Return the size in bytes of the blob accessible via the open
3282** [sqlite3_blob | blob-handle] passed as an argument.
3283*/
3284int sqlite3_blob_bytes(sqlite3_blob *);
3285
3286/*
3287** CAPI3REF: Read Data From A BLOB Incrementally
3288**
3289** This function is used to read data from an open
3290** [sqlite3_blob | blob-handle] into a caller supplied buffer.
3291** n bytes of data are copied into buffer
3292** z from the open blob, starting at offset iOffset.
3293**
3294** On success, SQLITE_OK is returned. Otherwise, an
3295** [SQLITE_ERROR | SQLite error code] or an
3296** [SQLITE_IOERR_READ | extended error code] is returned.
3297*/
3298int sqlite3_blob_read(sqlite3_blob *, void *z, int n, int iOffset);
3299
3300/*
3301** CAPI3REF: Write Data Into A BLOB Incrementally
3302**
3303** This function is used to write data into an open
3304** [sqlite3_blob | blob-handle] from a user supplied buffer.
3305** n bytes of data are copied from the buffer
3306** pointed to by z into the open blob, starting at offset iOffset.
3307**
3308** If the [sqlite3_blob | blob-handle] passed as the first argument
3309** was not opened for writing (the flags parameter to [sqlite3_blob_open()]
3310*** was zero), this function returns [SQLITE_READONLY].
3311**
3312** This function may only modify the contents of the blob, it is
3313** not possible to increase the size of a blob using this API. If
3314** offset iOffset is less than n bytes from the end of the blob,
3315** [SQLITE_ERROR] is returned and no data is written.
3316**
3317** On success, SQLITE_OK is returned. Otherwise, an
3318** [SQLITE_ERROR | SQLite error code] or an
3319** [SQLITE_IOERR_READ | extended error code] is returned.
3320*/
3321int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
3322
3323/*
3324** CAPI3REF: Virtual File System Objects
3325**
3326** A virtual filesystem (VFS) is an [sqlite3_vfs] object
3327** that SQLite uses to interact
3328** with the underlying operating system. Most builds come with a
3329** single default VFS that is appropriate for the host computer.
3330** New VFSes can be registered and existing VFSes can be unregistered.
3331** The following interfaces are provided.
3332**
3333** The sqlite3_vfs_find() interface returns a pointer to a VFS given its
3334** name. Names are case sensitive. If there is no match, a NULL
3335** pointer is returned. If zVfsName is NULL then the default
3336** VFS is returned.
3337**
3338** New VFSes are registered with sqlite3_vfs_register(). Each
3339** new VFS becomes the default VFS if the makeDflt flag is set.
3340** The same VFS can be registered multiple times without injury.
3341** To make an existing VFS into the default VFS, register it again
3342** with the makeDflt flag set. If two different VFSes with the
3343** same name are registered, the behavior is undefined. If a
3344** VFS is registered with a name that is NULL or an empty string,
3345** then the behavior is undefined.
3346**
3347** Unregister a VFS with the sqlite3_vfs_unregister() interface.
3348** If the default VFS is unregistered, another VFS is chosen as
3349** the default. The choice for the new VFS is arbitrary.
3350*/
3351sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
3352int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
3353int sqlite3_vfs_unregister(sqlite3_vfs*);
3354
3355/*
3356** CAPI3REF: Mutexes
3357**
3358** The SQLite core uses these routines for thread
3359** synchronization. Though they are intended for internal
3360** use by SQLite, code that links against SQLite is
3361** permitted to use any of these routines.
3362**
3363** The SQLite source code contains multiple implementations
3364** of these mutex routines. An appropriate implementation
3365** is selected automatically at compile-time. The following
3366** implementations are available in the SQLite core:
3367**
3368** <ul>
3369** <li> SQLITE_MUTEX_OS2
3370** <li> SQLITE_MUTEX_PTHREAD
3371** <li> SQLITE_MUTEX_W32
3372** <li> SQLITE_MUTEX_NOOP
3373** </ul>
3374**
3375** The SQLITE_MUTEX_NOOP implementation is a set of routines
3376** that does no real locking and is appropriate for use in
3377** a single-threaded application. The SQLITE_MUTEX_OS2,
3378** SQLITE_MUTEX_PTHREAD, and SQLITE_MUTEX_W32 implementations
3379** are appropriate for use on os/2, unix, and windows.
3380**
3381** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
3382** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
3383** implementation is included with the library. The
3384** mutex interface routines defined here become external
3385** references in the SQLite library for which implementations
3386** must be provided by the application. This facility allows an
3387** application that links against SQLite to provide its own mutex
3388** implementation without having to modify the SQLite core.
3389**
3390** The sqlite3_mutex_alloc() routine allocates a new
3391** mutex and returns a pointer to it. If it returns NULL
3392** that means that a mutex could not be allocated. SQLite
3393** will unwind its stack and return an error. The argument
3394** to sqlite3_mutex_alloc() is one of these integer constants:
3395**
3396** <ul>
3397** <li> SQLITE_MUTEX_FAST
3398** <li> SQLITE_MUTEX_RECURSIVE
3399** <li> SQLITE_MUTEX_STATIC_MASTER
3400** <li> SQLITE_MUTEX_STATIC_MEM
3401** <li> SQLITE_MUTEX_STATIC_MEM2
3402** <li> SQLITE_MUTEX_STATIC_PRNG
3403** <li> SQLITE_MUTEX_STATIC_LRU
3404** </ul>
3405**
3406** The first two constants cause sqlite3_mutex_alloc() to create
3407** a new mutex. The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
3408** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
3409** The mutex implementation does not need to make a distinction
3410** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
3411** not want to. But SQLite will only request a recursive mutex in
3412** cases where it really needs one. If a faster non-recursive mutex
3413** implementation is available on the host platform, the mutex subsystem
3414** might return such a mutex in response to SQLITE_MUTEX_FAST.
3415**
3416** The other allowed parameters to sqlite3_mutex_alloc() each return
3417** a pointer to a static preexisting mutex. Four static mutexes are
3418** used by the current version of SQLite. Future versions of SQLite
3419** may add additional static mutexes. Static mutexes are for internal
3420** use by SQLite only. Applications that use SQLite mutexes should
3421** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
3422** SQLITE_MUTEX_RECURSIVE.
3423**
3424** Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
3425** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
3426** returns a different mutex on every call. But for the static
3427** mutex types, the same mutex is returned on every call that has
3428** the same type number.
3429**
3430** The sqlite3_mutex_free() routine deallocates a previously
3431** allocated dynamic mutex. SQLite is careful to deallocate every
3432** dynamic mutex that it allocates. The dynamic mutexes must not be in
3433** use when they are deallocated. Attempting to deallocate a static
3434** mutex results in undefined behavior. SQLite never deallocates
3435** a static mutex.
3436**
3437** The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
3438** to enter a mutex. If another thread is already within the mutex,
3439** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
3440** SQLITE_BUSY. The sqlite3_mutex_try() interface returns SQLITE_OK
3441** upon successful entry. Mutexes created using SQLITE_MUTEX_RECURSIVE can
3442** be entered multiple times by the same thread. In such cases the,
3443** mutex must be exited an equal number of times before another thread
3444** can enter. If the same thread tries to enter any other kind of mutex
3445** more than once, the behavior is undefined. SQLite will never exhibit
3446** such behavior in its own use of mutexes.
3447**
3448** Some systems (ex: windows95) do not the operation implemented by
3449** sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() will
3450** always return SQLITE_BUSY. The SQLite core only ever uses
3451** sqlite3_mutex_try() as an optimization so this is acceptable behavior.
3452**
3453** The sqlite3_mutex_leave() routine exits a mutex that was
3454** previously entered by the same thread. The behavior
3455** is undefined if the mutex is not currently entered by the
3456** calling thread or is not currently allocated. SQLite will
3457** never do either.
3458**
3459** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
3460*/
3461sqlite3_mutex *sqlite3_mutex_alloc(int);
3462void sqlite3_mutex_free(sqlite3_mutex*);
3463void sqlite3_mutex_enter(sqlite3_mutex*);
3464int sqlite3_mutex_try(sqlite3_mutex*);
3465void sqlite3_mutex_leave(sqlite3_mutex*);
3466
3467/*
3468** CAPI3REF: Mutex Verifcation Routines
3469**
3470** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
3471** are intended for use inside assert() statements. The SQLite core
3472** never uses these routines except inside an assert() and applications
3473** are advised to follow the lead of the core. The core only
3474** provides implementations for these routines when it is compiled
3475** with the SQLITE_DEBUG flag. External mutex implementations
3476** are only required to provide these routines if SQLITE_DEBUG is
3477** defined and if NDEBUG is not defined.
3478**
3479** These routines should return true if the mutex in their argument
3480** is held or not held, respectively, by the calling thread.
3481**
3482** The implementation is not required to provided versions of these
3483** routines that actually work.
3484** If the implementation does not provide working
3485** versions of these routines, it should at least provide stubs
3486** that always return true so that one does not get spurious
3487** assertion failures.
3488**
3489** If the argument to sqlite3_mutex_held() is a NULL pointer then
3490** the routine should return 1. This seems counter-intuitive since
3491** clearly the mutex cannot be held if it does not exist. But the
3492** the reason the mutex does not exist is because the build is not
3493** using mutexes. And we do not want the assert() containing the
3494** call to sqlite3_mutex_held() to fail, so a non-zero return is
3495** the appropriate thing to do. The sqlite3_mutex_notheld()
3496** interface should also return 1 when given a NULL pointer.
3497*/
3498int sqlite3_mutex_held(sqlite3_mutex*);
3499int sqlite3_mutex_notheld(sqlite3_mutex*);
3500
3501/*
3502** CAPI3REF: Mutex Types
3503**
3504** The [sqlite3_mutex_alloc()] interface takes a single argument
3505** which is one of these integer constants.
3506*/
3507#define SQLITE_MUTEX_FAST 0
3508#define SQLITE_MUTEX_RECURSIVE 1
3509#define SQLITE_MUTEX_STATIC_MASTER 2
3510#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */
3511#define SQLITE_MUTEX_STATIC_MEM2 4 /* sqlite3_release_memory() */
3512#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */
3513#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */
3514
3515/*
3516** CAPI3REF: Low-Level Control Of Database Files
3517**
3518** The [sqlite3_file_control()] interface makes a direct call to the
3519** xFileControl method for the [sqlite3_io_methods] object associated
3520** with a particular database identified by the second argument. The
3521** name of the database is the name assigned to the database by the
3522** <a href="lang_attach.html">ATTACH</a> SQL command that opened the
3523** database. To control the main database file, use the name "main"
3524** or a NULL pointer. The third and fourth parameters to this routine
3525** are passed directly through to the second and third parameters of
3526** the xFileControl method. The return value of the xFileControl
3527** method becomes the return value of this routine.
3528**
3529** If the second parameter (zDbName) does not match the name of any
3530** open database file, then SQLITE_ERROR is returned. This error
3531** code is not remembered and will not be recalled by [sqlite3_errcode()]
3532** or [sqlite3_errmsg()]. The underlying xFileControl method might
3533** also return SQLITE_ERROR. There is no way to distinguish between
3534** an incorrect zDbName and an SQLITE_ERROR return from the underlying
3535** xFileControl method.
3536**
3537** See also: [SQLITE_FCNTL_LOCKSTATE]
3538*/
3539int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
3540
3541/*
3542** Undo the hack that converts floating point types to integer for
3543** builds on processors without floating point support.
3544*/
3545#ifdef SQLITE_OMIT_FLOATING_POINT
3546# undef double
3547#endif
3548
3549#ifdef __cplusplus
3550} /* End of the 'extern "C"' block */
3551#endif
3552#endif