1/*
2** 2001 September 15
3**
4** The author disclaims copyright to this source code.  In place of
5** a legal notice, here is a blessing:
6**
7**    May you do good and not evil.
8**    May you find forgiveness for yourself and forgive others.
9**    May you share freely, never taking more than you give.
10**
11*************************************************************************
12** This header file defines the interface that the SQLite library
13** presents to client programs.  If a C-function, structure, datatype,
14** or constant definition does not appear in this file, then it is
15** not a published API of SQLite, is subject to change without
16** notice, and should not be referenced by programs that use SQLite.
17**
18** Some of the definitions that are in this file are marked as
19** "experimental".  Experimental interfaces are normally new
20** features recently added to SQLite.  We do not anticipate changes
21** to experimental interfaces but reserve the right to make minor changes
22** if experience from use "in the wild" suggest such changes are prudent.
23**
24** The official C-language API documentation for SQLite is derived
25** from comments in this file.  This file is the authoritative source
26** on how SQLite interfaces are suppose to operate.
27**
28** The name of this file under configuration management is "sqlite.h.in".
29** The makefile makes some minor changes to this file (such as inserting
30** the version number) and changes its name to "sqlite3.h" as
31** part of the build process.
32*/
33#ifndef _SQLITE3_H_
34#define _SQLITE3_H_
35#include <stdarg.h>     /* Needed for the definition of va_list */
36
37/*
38** Make sure we can call this stuff from C++.
39*/
40#ifdef __cplusplus
41extern "C" {
42#endif
43
44
45/*
46** Add the ability to override 'extern'
47*/
48#ifndef SQLITE_EXTERN
49# define SQLITE_EXTERN extern
50#endif
51
52/*
53** These no-op macros are used in front of interfaces to mark those
54** interfaces as either deprecated or experimental.  New applications
55** should not use deprecated interfaces - they are support for backwards
56** compatibility only.  Application writers should be aware that
57** experimental interfaces are subject to change in point releases.
58**
59** These macros used to resolve to various kinds of compiler magic that
60** would generate warning messages when they were used.  But that
61** compiler magic ended up generating such a flurry of bug reports
62** that we have taken it all out and gone back to using simple
63** noop macros.
64*/
65#define SQLITE_DEPRECATED
66#define SQLITE_EXPERIMENTAL
67
68/*
69** Ensure these symbols were not defined by some previous header file.
70*/
71#ifdef SQLITE_VERSION
72# undef SQLITE_VERSION
73#endif
74#ifdef SQLITE_VERSION_NUMBER
75# undef SQLITE_VERSION_NUMBER
76#endif
77
78/*
79** CAPI3REF: Compile-Time Library Version Numbers
80**
81** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header
82** evaluates to a string literal that is the SQLite version in the
83** format "X.Y.Z" where X is the major version number (always 3 for
84** SQLite3) and Y is the minor version number and Z is the release number.)^
85** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer
86** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same
87** numbers used in [SQLITE_VERSION].)^
88** The SQLITE_VERSION_NUMBER for any given release of SQLite will also
89** be larger than the release from which it is derived.  Either Y will
90** be held constant and Z will be incremented or else Y will be incremented
91** and Z will be reset to zero.
92**
93** Since version 3.6.18, SQLite source code has been stored in the
94** <a href="http://www.fossil-scm.org/">Fossil configuration management
95** system</a>.  ^The SQLITE_SOURCE_ID macro evaluates to
96** a string which identifies a particular check-in of SQLite
97** within its configuration management system.  ^The SQLITE_SOURCE_ID
98** string contains the date and time of the check-in (UTC) and an SHA1
99** hash of the entire source tree.
100**
101** See also: [sqlite3_libversion()],
102** [sqlite3_libversion_number()], [sqlite3_sourceid()],
103** [sqlite_version()] and [sqlite_source_id()].
104*/
105#define SQLITE_VERSION        "--VERS--"
106#define SQLITE_VERSION_NUMBER --VERSION-NUMBER--
107#define SQLITE_SOURCE_ID      "--SOURCE-ID--"
108
109/*
110** CAPI3REF: Run-Time Library Version Numbers
111** KEYWORDS: sqlite3_version, sqlite3_sourceid
112**
113** These interfaces provide the same information as the [SQLITE_VERSION],
114** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros
115** but are associated with the library instead of the header file.  ^(Cautious
116** programmers might include assert() statements in their application to
117** verify that values returned by these interfaces match the macros in
118** the header, and thus insure that the application is
119** compiled with matching library and header files.
120**
121** <blockquote><pre>
122** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
123** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 );
124** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
125** </pre></blockquote>)^
126**
127** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION]
128** macro.  ^The sqlite3_libversion() function returns a pointer to the
129** to the sqlite3_version[] string constant.  The sqlite3_libversion()
130** function is provided for use in DLLs since DLL users usually do not have
131** direct access to string constants within the DLL.  ^The
132** sqlite3_libversion_number() function returns an integer equal to
133** [SQLITE_VERSION_NUMBER].  ^The sqlite3_sourceid() function returns
134** a pointer to a string constant whose value is the same as the
135** [SQLITE_SOURCE_ID] C preprocessor macro.
136**
137** See also: [sqlite_version()] and [sqlite_source_id()].
138*/
139SQLITE_EXTERN const char sqlite3_version[];
140const char *sqlite3_libversion(void);
141const char *sqlite3_sourceid(void);
142int sqlite3_libversion_number(void);
143
144/*
145** CAPI3REF: Run-Time Library Compilation Options Diagnostics
146**
147** ^The sqlite3_compileoption_used() function returns 0 or 1
148** indicating whether the specified option was defined at
149** compile time.  ^The SQLITE_ prefix may be omitted from the
150** option name passed to sqlite3_compileoption_used().
151**
152** ^The sqlite3_compileoption_get() function allows iterating
153** over the list of options that were defined at compile time by
154** returning the N-th compile time option string.  ^If N is out of range,
155** sqlite3_compileoption_get() returns a NULL pointer.  ^The SQLITE_
156** prefix is omitted from any strings returned by
157** sqlite3_compileoption_get().
158**
159** ^Support for the diagnostic functions sqlite3_compileoption_used()
160** and sqlite3_compileoption_get() may be omitted by specifying the
161** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time.
162**
163** See also: SQL functions [sqlite_compileoption_used()] and
164** [sqlite_compileoption_get()] and the [compile_options pragma].
165*/
166#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
167int sqlite3_compileoption_used(const char *zOptName);
168const char *sqlite3_compileoption_get(int N);
169#endif
170
171/*
172** CAPI3REF: Test To See If The Library Is Threadsafe
173**
174** ^The sqlite3_threadsafe() function returns zero if and only if
175** SQLite was compiled mutexing code omitted due to the
176** [SQLITE_THREADSAFE] compile-time option being set to 0.
177**
178** SQLite can be compiled with or without mutexes.  When
179** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
180** are enabled and SQLite is threadsafe.  When the
181** [SQLITE_THREADSAFE] macro is 0,
182** the mutexes are omitted.  Without the mutexes, it is not safe
183** to use SQLite concurrently from more than one thread.
184**
185** Enabling mutexes incurs a measurable performance penalty.
186** So if speed is of utmost importance, it makes sense to disable
187** the mutexes.  But for maximum safety, mutexes should be enabled.
188** ^The default behavior is for mutexes to be enabled.
189**
190** This interface can be used by an application to make sure that the
191** version of SQLite that it is linking against was compiled with
192** the desired setting of the [SQLITE_THREADSAFE] macro.
193**
194** This interface only reports on the compile-time mutex setting
195** of the [SQLITE_THREADSAFE] flag.  If SQLite is compiled with
196** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
197** can be fully or partially disabled using a call to [sqlite3_config()]
198** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD],
199** or [SQLITE_CONFIG_MUTEX].  ^(The return value of the
200** sqlite3_threadsafe() function shows only the compile-time setting of
201** thread safety, not any run-time changes to that setting made by
202** sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
203** is unchanged by calls to sqlite3_config().)^
204**
205** See the [threading mode] documentation for additional information.
206*/
207int sqlite3_threadsafe(void);
208
209/*
210** CAPI3REF: Database Connection Handle
211** KEYWORDS: {database connection} {database connections}
212**
213** Each open SQLite database is represented by a pointer to an instance of
214** the opaque structure named "sqlite3".  It is useful to think of an sqlite3
215** pointer as an object.  The [sqlite3_open()], [sqlite3_open16()], and
216** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
217** is its destructor.  There are many other interfaces (such as
218** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
219** [sqlite3_busy_timeout()] to name but three) that are methods on an
220** sqlite3 object.
221*/
222typedef struct sqlite3 sqlite3;
223
224/*
225** CAPI3REF: 64-Bit Integer Types
226** KEYWORDS: sqlite_int64 sqlite_uint64
227**
228** Because there is no cross-platform way to specify 64-bit integer types
229** SQLite includes typedefs for 64-bit signed and unsigned integers.
230**
231** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
232** The sqlite_int64 and sqlite_uint64 types are supported for backwards
233** compatibility only.
234**
235** ^The sqlite3_int64 and sqlite_int64 types can store integer values
236** between -9223372036854775808 and +9223372036854775807 inclusive.  ^The
237** sqlite3_uint64 and sqlite_uint64 types can store integer values
238** between 0 and +18446744073709551615 inclusive.
239*/
240#ifdef SQLITE_INT64_TYPE
241  typedef SQLITE_INT64_TYPE sqlite_int64;
242  typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
243#elif defined(_MSC_VER) || defined(__BORLANDC__)
244  typedef __int64 sqlite_int64;
245  typedef unsigned __int64 sqlite_uint64;
246#else
247  typedef long long int sqlite_int64;
248  typedef unsigned long long int sqlite_uint64;
249#endif
250typedef sqlite_int64 sqlite3_int64;
251typedef sqlite_uint64 sqlite3_uint64;
252
253/*
254** If compiling for a processor that lacks floating point support,
255** substitute integer for floating-point.
256*/
257#ifdef SQLITE_OMIT_FLOATING_POINT
258# define double sqlite3_int64
259#endif
260
261/*
262** CAPI3REF: Closing A Database Connection
263**
264** ^The sqlite3_close() routine is the destructor for the [sqlite3] object.
265** ^Calls to sqlite3_close() return SQLITE_OK if the [sqlite3] object is
266** successfully destroyed and all associated resources are deallocated.
267**
268** Applications must [sqlite3_finalize | finalize] all [prepared statements]
269** and [sqlite3_blob_close | close] all [BLOB handles] associated with
270** the [sqlite3] object prior to attempting to close the object.  ^If
271** sqlite3_close() is called on a [database connection] that still has
272** outstanding [prepared statements] or [BLOB handles], then it returns
273** SQLITE_BUSY.
274**
275** ^If [sqlite3_close()] is invoked while a transaction is open,
276** the transaction is automatically rolled back.
277**
278** The C parameter to [sqlite3_close(C)] must be either a NULL
279** pointer or an [sqlite3] object pointer obtained
280** from [sqlite3_open()], [sqlite3_open16()], or
281** [sqlite3_open_v2()], and not previously closed.
282** ^Calling sqlite3_close() with a NULL pointer argument is a
283** harmless no-op.
284*/
285int sqlite3_close(sqlite3 *);
286
287/*
288** The type for a callback function.
289** This is legacy and deprecated.  It is included for historical
290** compatibility and is not documented.
291*/
292typedef int (*sqlite3_callback)(void*,int,char**, char**);
293
294/*
295** CAPI3REF: One-Step Query Execution Interface
296**
297** The sqlite3_exec() interface is a convenience wrapper around
298** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
299** that allows an application to run multiple statements of SQL
300** without having to use a lot of C code.
301**
302** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
303** semicolon-separate SQL statements passed into its 2nd argument,
304** in the context of the [database connection] passed in as its 1st
305** argument.  ^If the callback function of the 3rd argument to
306** sqlite3_exec() is not NULL, then it is invoked for each result row
307** coming out of the evaluated SQL statements.  ^The 4th argument to
308** to sqlite3_exec() is relayed through to the 1st argument of each
309** callback invocation.  ^If the callback pointer to sqlite3_exec()
310** is NULL, then no callback is ever invoked and result rows are
311** ignored.
312**
313** ^If an error occurs while evaluating the SQL statements passed into
314** sqlite3_exec(), then execution of the current statement stops and
315** subsequent statements are skipped.  ^If the 5th parameter to sqlite3_exec()
316** is not NULL then any error message is written into memory obtained
317** from [sqlite3_malloc()] and passed back through the 5th parameter.
318** To avoid memory leaks, the application should invoke [sqlite3_free()]
319** on error message strings returned through the 5th parameter of
320** of sqlite3_exec() after the error message string is no longer needed.
321** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
322** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
323** NULL before returning.
324**
325** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
326** routine returns SQLITE_ABORT without invoking the callback again and
327** without running any subsequent SQL statements.
328**
329** ^The 2nd argument to the sqlite3_exec() callback function is the
330** number of columns in the result.  ^The 3rd argument to the sqlite3_exec()
331** callback is an array of pointers to strings obtained as if from
332** [sqlite3_column_text()], one for each column.  ^If an element of a
333** result row is NULL then the corresponding string pointer for the
334** sqlite3_exec() callback is a NULL pointer.  ^The 4th argument to the
335** sqlite3_exec() callback is an array of pointers to strings where each
336** entry represents the name of corresponding result column as obtained
337** from [sqlite3_column_name()].
338**
339** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
340** to an empty string, or a pointer that contains only whitespace and/or
341** SQL comments, then no SQL statements are evaluated and the database
342** is not changed.
343**
344** Restrictions:
345**
346** <ul>
347** <li> The application must insure that the 1st parameter to sqlite3_exec()
348**      is a valid and open [database connection].
349** <li> The application must not close [database connection] specified by
350**      the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
351** <li> The application must not modify the SQL statement text passed into
352**      the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
353** </ul>
354*/
355int sqlite3_exec(
356  sqlite3*,                                  /* An open database */
357  const char *sql,                           /* SQL to be evaluated */
358  int (*callback)(void*,int,char**,char**),  /* Callback function */
359  void *,                                    /* 1st argument to callback */
360  char **errmsg                              /* Error msg written here */
361);
362
363/*
364** CAPI3REF: Result Codes
365** KEYWORDS: SQLITE_OK {error code} {error codes}
366** KEYWORDS: {result code} {result codes}
367**
368** Many SQLite functions return an integer result code from the set shown
369** here in order to indicates success or failure.
370**
371** New error codes may be added in future versions of SQLite.
372**
373** See also: [SQLITE_IOERR_READ | extended result codes]
374*/
375#define SQLITE_OK           0   /* Successful result */
376/* beginning-of-error-codes */
377#define SQLITE_ERROR        1   /* SQL error or missing database */
378#define SQLITE_INTERNAL     2   /* Internal logic error in SQLite */
379#define SQLITE_PERM         3   /* Access permission denied */
380#define SQLITE_ABORT        4   /* Callback routine requested an abort */
381#define SQLITE_BUSY         5   /* The database file is locked */
382#define SQLITE_LOCKED       6   /* A table in the database is locked */
383#define SQLITE_NOMEM        7   /* A malloc() failed */
384#define SQLITE_READONLY     8   /* Attempt to write a readonly database */
385#define SQLITE_INTERRUPT    9   /* Operation terminated by sqlite3_interrupt()*/
386#define SQLITE_IOERR       10   /* Some kind of disk I/O error occurred */
387#define SQLITE_CORRUPT     11   /* The database disk image is malformed */
388#define SQLITE_NOTFOUND    12   /* Unknown opcode in sqlite3_file_control() */
389#define SQLITE_FULL        13   /* Insertion failed because database is full */
390#define SQLITE_CANTOPEN    14   /* Unable to open the database file */
391#define SQLITE_PROTOCOL    15   /* Database lock protocol error */
392#define SQLITE_EMPTY       16   /* Database is empty */
393#define SQLITE_SCHEMA      17   /* The database schema changed */
394#define SQLITE_TOOBIG      18   /* String or BLOB exceeds size limit */
395#define SQLITE_CONSTRAINT  19   /* Abort due to constraint violation */
396#define SQLITE_MISMATCH    20   /* Data type mismatch */
397#define SQLITE_MISUSE      21   /* Library used incorrectly */
398#define SQLITE_NOLFS       22   /* Uses OS features not supported on host */
399#define SQLITE_AUTH        23   /* Authorization denied */
400#define SQLITE_FORMAT      24   /* Auxiliary database format error */
401#define SQLITE_RANGE       25   /* 2nd parameter to sqlite3_bind out of range */
402#define SQLITE_NOTADB      26   /* File opened that is not a database file */
403#define SQLITE_ROW         100  /* sqlite3_step() has another row ready */
404#define SQLITE_DONE        101  /* sqlite3_step() has finished executing */
405/* end-of-error-codes */
406
407/*
408** CAPI3REF: Extended Result Codes
409** KEYWORDS: {extended error code} {extended error codes}
410** KEYWORDS: {extended result code} {extended result codes}
411**
412** In its default configuration, SQLite API routines return one of 26 integer
413** [SQLITE_OK | result codes].  However, experience has shown that many of
414** these result codes are too coarse-grained.  They do not provide as
415** much information about problems as programmers might like.  In an effort to
416** address this, newer versions of SQLite (version 3.3.8 and later) include
417** support for additional result codes that provide more detailed information
418** about errors. The extended result codes are enabled or disabled
419** on a per database connection basis using the
420** [sqlite3_extended_result_codes()] API.
421**
422** Some of the available extended result codes are listed here.
423** One may expect the number of extended result codes will be expand
424** over time.  Software that uses extended result codes should expect
425** to see new result codes in future releases of SQLite.
426**
427** The SQLITE_OK result code will never be extended.  It will always
428** be exactly zero.
429*/
430#define SQLITE_IOERR_READ              (SQLITE_IOERR | (1<<8))
431#define SQLITE_IOERR_SHORT_READ        (SQLITE_IOERR | (2<<8))
432#define SQLITE_IOERR_WRITE             (SQLITE_IOERR | (3<<8))
433#define SQLITE_IOERR_FSYNC             (SQLITE_IOERR | (4<<8))
434#define SQLITE_IOERR_DIR_FSYNC         (SQLITE_IOERR | (5<<8))
435#define SQLITE_IOERR_TRUNCATE          (SQLITE_IOERR | (6<<8))
436#define SQLITE_IOERR_FSTAT             (SQLITE_IOERR | (7<<8))
437#define SQLITE_IOERR_UNLOCK            (SQLITE_IOERR | (8<<8))
438#define SQLITE_IOERR_RDLOCK            (SQLITE_IOERR | (9<<8))
439#define SQLITE_IOERR_DELETE            (SQLITE_IOERR | (10<<8))
440#define SQLITE_IOERR_BLOCKED           (SQLITE_IOERR | (11<<8))
441#define SQLITE_IOERR_NOMEM             (SQLITE_IOERR | (12<<8))
442#define SQLITE_IOERR_ACCESS            (SQLITE_IOERR | (13<<8))
443#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
444#define SQLITE_IOERR_LOCK              (SQLITE_IOERR | (15<<8))
445#define SQLITE_IOERR_CLOSE             (SQLITE_IOERR | (16<<8))
446#define SQLITE_IOERR_DIR_CLOSE         (SQLITE_IOERR | (17<<8))
447#define SQLITE_IOERR_SHMOPEN           (SQLITE_IOERR | (18<<8))
448#define SQLITE_IOERR_SHMSIZE           (SQLITE_IOERR | (19<<8))
449#define SQLITE_IOERR_SHMLOCK           (SQLITE_IOERR | (20<<8))
450#define SQLITE_LOCKED_SHAREDCACHE      (SQLITE_LOCKED |  (1<<8))
451#define SQLITE_BUSY_RECOVERY           (SQLITE_BUSY   |  (1<<8))
452#define SQLITE_CANTOPEN_NOTEMPDIR      (SQLITE_CANTOPEN | (1<<8))
453
454/*
455** CAPI3REF: Flags For File Open Operations
456**
457** These bit values are intended for use in the
458** 3rd parameter to the [sqlite3_open_v2()] interface and
459** in the 4th parameter to the xOpen method of the
460** [sqlite3_vfs] object.
461*/
462#define SQLITE_OPEN_READONLY         0x00000001  /* Ok for sqlite3_open_v2() */
463#define SQLITE_OPEN_READWRITE        0x00000002  /* Ok for sqlite3_open_v2() */
464#define SQLITE_OPEN_CREATE           0x00000004  /* Ok for sqlite3_open_v2() */
465#define SQLITE_OPEN_DELETEONCLOSE    0x00000008  /* VFS only */
466#define SQLITE_OPEN_EXCLUSIVE        0x00000010  /* VFS only */
467#define SQLITE_OPEN_AUTOPROXY        0x00000020  /* VFS only */
468#define SQLITE_OPEN_MAIN_DB          0x00000100  /* VFS only */
469#define SQLITE_OPEN_TEMP_DB          0x00000200  /* VFS only */
470#define SQLITE_OPEN_TRANSIENT_DB     0x00000400  /* VFS only */
471#define SQLITE_OPEN_MAIN_JOURNAL     0x00000800  /* VFS only */
472#define SQLITE_OPEN_TEMP_JOURNAL     0x00001000  /* VFS only */
473#define SQLITE_OPEN_SUBJOURNAL       0x00002000  /* VFS only */
474#define SQLITE_OPEN_MASTER_JOURNAL   0x00004000  /* VFS only */
475#define SQLITE_OPEN_NOMUTEX          0x00008000  /* Ok for sqlite3_open_v2() */
476#define SQLITE_OPEN_FULLMUTEX        0x00010000  /* Ok for sqlite3_open_v2() */
477#define SQLITE_OPEN_SHAREDCACHE      0x00020000  /* Ok for sqlite3_open_v2() */
478#define SQLITE_OPEN_PRIVATECACHE     0x00040000  /* Ok for sqlite3_open_v2() */
479#define SQLITE_OPEN_WAL              0x00080000  /* VFS only */
480
481/* Reserved:                         0x00F00000 */
482
483/*
484** CAPI3REF: Device Characteristics
485**
486** The xDeviceCharacteristics method of the [sqlite3_io_methods]
487** object returns an integer which is a vector of the these
488** bit values expressing I/O characteristics of the mass storage
489** device that holds the file that the [sqlite3_io_methods]
490** refers to.
491**
492** The SQLITE_IOCAP_ATOMIC property means that all writes of
493** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
494** mean that writes of blocks that are nnn bytes in size and
495** are aligned to an address which is an integer multiple of
496** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
497** that when data is appended to a file, the data is appended
498** first then the size of the file is extended, never the other
499** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
500** information is written to disk in the same order as calls
501** to xWrite().
502*/
503#define SQLITE_IOCAP_ATOMIC                 0x00000001
504#define SQLITE_IOCAP_ATOMIC512              0x00000002
505#define SQLITE_IOCAP_ATOMIC1K               0x00000004
506#define SQLITE_IOCAP_ATOMIC2K               0x00000008
507#define SQLITE_IOCAP_ATOMIC4K               0x00000010
508#define SQLITE_IOCAP_ATOMIC8K               0x00000020
509#define SQLITE_IOCAP_ATOMIC16K              0x00000040
510#define SQLITE_IOCAP_ATOMIC32K              0x00000080
511#define SQLITE_IOCAP_ATOMIC64K              0x00000100
512#define SQLITE_IOCAP_SAFE_APPEND            0x00000200
513#define SQLITE_IOCAP_SEQUENTIAL             0x00000400
514#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN  0x00000800
515
516/*
517** CAPI3REF: File Locking Levels
518**
519** SQLite uses one of these integer values as the second
520** argument to calls it makes to the xLock() and xUnlock() methods
521** of an [sqlite3_io_methods] object.
522*/
523#define SQLITE_LOCK_NONE          0
524#define SQLITE_LOCK_SHARED        1
525#define SQLITE_LOCK_RESERVED      2
526#define SQLITE_LOCK_PENDING       3
527#define SQLITE_LOCK_EXCLUSIVE     4
528
529/*
530** CAPI3REF: Synchronization Type Flags
531**
532** When SQLite invokes the xSync() method of an
533** [sqlite3_io_methods] object it uses a combination of
534** these integer values as the second argument.
535**
536** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
537** sync operation only needs to flush data to mass storage.  Inode
538** information need not be flushed. If the lower four bits of the flag
539** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
540** If the lower four bits equal SQLITE_SYNC_FULL, that means
541** to use Mac OS X style fullsync instead of fsync().
542**
543** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
544** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
545** settings.  The [synchronous pragma] determines when calls to the
546** xSync VFS method occur and applies uniformly across all platforms.
547** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
548** energetic or rigorous or forceful the sync operations are and
549** only make a difference on Mac OSX for the default SQLite code.
550** (Third-party VFS implementations might also make the distinction
551** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
552** operating systems natively supported by SQLite, only Mac OSX
553** cares about the difference.)
554*/
555#define SQLITE_SYNC_NORMAL        0x00002
556#define SQLITE_SYNC_FULL          0x00003
557#define SQLITE_SYNC_DATAONLY      0x00010
558
559/*
560** CAPI3REF: OS Interface Open File Handle
561**
562** An [sqlite3_file] object represents an open file in the
563** [sqlite3_vfs | OS interface layer].  Individual OS interface
564** implementations will
565** want to subclass this object by appending additional fields
566** for their own use.  The pMethods entry is a pointer to an
567** [sqlite3_io_methods] object that defines methods for performing
568** I/O operations on the open file.
569*/
570typedef struct sqlite3_file sqlite3_file;
571struct sqlite3_file {
572  const struct sqlite3_io_methods *pMethods;  /* Methods for an open file */
573};
574
575/*
576** CAPI3REF: OS Interface File Virtual Methods Object
577**
578** Every file opened by the [sqlite3_vfs] xOpen method populates an
579** [sqlite3_file] object (or, more commonly, a subclass of the
580** [sqlite3_file] object) with a pointer to an instance of this object.
581** This object defines the methods used to perform various operations
582** against the open file represented by the [sqlite3_file] object.
583**
584** If the xOpen method sets the sqlite3_file.pMethods element
585** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
586** may be invoked even if the xOpen reported that it failed.  The
587** only way to prevent a call to xClose following a failed xOpen
588** is for the xOpen to set the sqlite3_file.pMethods element to NULL.
589**
590** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
591** [SQLITE_SYNC_FULL].  The first choice is the normal fsync().
592** The second choice is a Mac OS X style fullsync.  The [SQLITE_SYNC_DATAONLY]
593** flag may be ORed in to indicate that only the data of the file
594** and not its inode needs to be synced.
595**
596** The integer values to xLock() and xUnlock() are one of
597** <ul>
598** <li> [SQLITE_LOCK_NONE],
599** <li> [SQLITE_LOCK_SHARED],
600** <li> [SQLITE_LOCK_RESERVED],
601** <li> [SQLITE_LOCK_PENDING], or
602** <li> [SQLITE_LOCK_EXCLUSIVE].
603** </ul>
604** xLock() increases the lock. xUnlock() decreases the lock.
605** The xCheckReservedLock() method checks whether any database connection,
606** either in this process or in some other process, is holding a RESERVED,
607** PENDING, or EXCLUSIVE lock on the file.  It returns true
608** if such a lock exists and false otherwise.
609**
610** The xFileControl() method is a generic interface that allows custom
611** VFS implementations to directly control an open file using the
612** [sqlite3_file_control()] interface.  The second "op" argument is an
613** integer opcode.  The third argument is a generic pointer intended to
614** point to a structure that may contain arguments or space in which to
615** write return values.  Potential uses for xFileControl() might be
616** functions to enable blocking locks with timeouts, to change the
617** locking strategy (for example to use dot-file locks), to inquire
618** about the status of a lock, or to break stale locks.  The SQLite
619** core reserves all opcodes less than 100 for its own use.
620** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available.
621** Applications that define a custom xFileControl method should use opcodes
622** greater than 100 to avoid conflicts.  VFS implementations should
623** return [SQLITE_NOTFOUND] for file control opcodes that they do not
624** recognize.
625**
626** The xSectorSize() method returns the sector size of the
627** device that underlies the file.  The sector size is the
628** minimum write that can be performed without disturbing
629** other bytes in the file.  The xDeviceCharacteristics()
630** method returns a bit vector describing behaviors of the
631** underlying device:
632**
633** <ul>
634** <li> [SQLITE_IOCAP_ATOMIC]
635** <li> [SQLITE_IOCAP_ATOMIC512]
636** <li> [SQLITE_IOCAP_ATOMIC1K]
637** <li> [SQLITE_IOCAP_ATOMIC2K]
638** <li> [SQLITE_IOCAP_ATOMIC4K]
639** <li> [SQLITE_IOCAP_ATOMIC8K]
640** <li> [SQLITE_IOCAP_ATOMIC16K]
641** <li> [SQLITE_IOCAP_ATOMIC32K]
642** <li> [SQLITE_IOCAP_ATOMIC64K]
643** <li> [SQLITE_IOCAP_SAFE_APPEND]
644** <li> [SQLITE_IOCAP_SEQUENTIAL]
645** </ul>
646**
647** The SQLITE_IOCAP_ATOMIC property means that all writes of
648** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
649** mean that writes of blocks that are nnn bytes in size and
650** are aligned to an address which is an integer multiple of
651** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
652** that when data is appended to a file, the data is appended
653** first then the size of the file is extended, never the other
654** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
655** information is written to disk in the same order as calls
656** to xWrite().
657**
658** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
659** in the unread portions of the buffer with zeros.  A VFS that
660** fails to zero-fill short reads might seem to work.  However,
661** failure to zero-fill short reads will eventually lead to
662** database corruption.
663*/
664typedef struct sqlite3_io_methods sqlite3_io_methods;
665struct sqlite3_io_methods {
666  int iVersion;
667  int (*xClose)(sqlite3_file*);
668  int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
669  int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
670  int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
671  int (*xSync)(sqlite3_file*, int flags);
672  int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
673  int (*xLock)(sqlite3_file*, int);
674  int (*xUnlock)(sqlite3_file*, int);
675  int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
676  int (*xFileControl)(sqlite3_file*, int op, void *pArg);
677  int (*xSectorSize)(sqlite3_file*);
678  int (*xDeviceCharacteristics)(sqlite3_file*);
679  /* Methods above are valid for version 1 */
680  int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
681  int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
682  void (*xShmBarrier)(sqlite3_file*);
683  int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
684  /* Methods above are valid for version 2 */
685  /* Additional methods may be added in future releases */
686};
687
688/*
689** CAPI3REF: Standard File Control Opcodes
690**
691** These integer constants are opcodes for the xFileControl method
692** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
693** interface.
694**
695** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging.  This
696** opcode causes the xFileControl method to write the current state of
697** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
698** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
699** into an integer that the pArg argument points to. This capability
700** is used during testing and only needs to be supported when SQLITE_TEST
701** is defined.
702**
703** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
704** layer a hint of how large the database file will grow to be during the
705** current transaction.  This hint is not guaranteed to be accurate but it
706** is often close.  The underlying VFS might choose to preallocate database
707** file space based on this hint in order to help writes to the database
708** file run faster.
709**
710** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
711** extends and truncates the database file in chunks of a size specified
712** by the user. The fourth argument to [sqlite3_file_control()] should
713** point to an integer (type int) containing the new chunk-size to use
714** for the nominated database. Allocating database file space in large
715** chunks (say 1MB at a time), may reduce file-system fragmentation and
716** improve performance on some systems.
717**
718** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
719** to the [sqlite3_file] object associated with a particular database
720** connection.  See the [sqlite3_file_control()] documentation for
721** additional information.
722**
723** ^(The [SQLITE_FCNTL_SYNC_OMITTED] opcode is generated internally by
724** SQLite and sent to all VFSes in place of a call to the xSync method
725** when the database connection has [PRAGMA synchronous] set to OFF.)^
726** Some specialized VFSes need this signal in order to operate correctly
727** when [PRAGMA synchronous | PRAGMA synchronous=OFF] is set, but most
728** VFSes do not need this signal and should silently ignore this opcode.
729** Applications should not call [sqlite3_file_control()] with this
730** opcode as doing so may disrupt the operation of the specialized VFSes
731** that do require it.
732*/
733#define SQLITE_FCNTL_LOCKSTATE        1
734#define SQLITE_GET_LOCKPROXYFILE      2
735#define SQLITE_SET_LOCKPROXYFILE      3
736#define SQLITE_LAST_ERRNO             4
737#define SQLITE_FCNTL_SIZE_HINT        5
738#define SQLITE_FCNTL_CHUNK_SIZE       6
739#define SQLITE_FCNTL_FILE_POINTER     7
740#define SQLITE_FCNTL_SYNC_OMITTED     8
741
742
743/*
744** CAPI3REF: Mutex Handle
745**
746** The mutex module within SQLite defines [sqlite3_mutex] to be an
747** abstract type for a mutex object.  The SQLite core never looks
748** at the internal representation of an [sqlite3_mutex].  It only
749** deals with pointers to the [sqlite3_mutex] object.
750**
751** Mutexes are created using [sqlite3_mutex_alloc()].
752*/
753typedef struct sqlite3_mutex sqlite3_mutex;
754
755/*
756** CAPI3REF: OS Interface Object
757**
758** An instance of the sqlite3_vfs object defines the interface between
759** the SQLite core and the underlying operating system.  The "vfs"
760** in the name of the object stands for "virtual file system".
761**
762** The value of the iVersion field is initially 1 but may be larger in
763** future versions of SQLite.  Additional fields may be appended to this
764** object when the iVersion value is increased.  Note that the structure
765** of the sqlite3_vfs object changes in the transaction between
766** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not
767** modified.
768**
769** The szOsFile field is the size of the subclassed [sqlite3_file]
770** structure used by this VFS.  mxPathname is the maximum length of
771** a pathname in this VFS.
772**
773** Registered sqlite3_vfs objects are kept on a linked list formed by
774** the pNext pointer.  The [sqlite3_vfs_register()]
775** and [sqlite3_vfs_unregister()] interfaces manage this list
776** in a thread-safe way.  The [sqlite3_vfs_find()] interface
777** searches the list.  Neither the application code nor the VFS
778** implementation should use the pNext pointer.
779**
780** The pNext field is the only field in the sqlite3_vfs
781** structure that SQLite will ever modify.  SQLite will only access
782** or modify this field while holding a particular static mutex.
783** The application should never modify anything within the sqlite3_vfs
784** object once the object has been registered.
785**
786** The zName field holds the name of the VFS module.  The name must
787** be unique across all VFS modules.
788**
789** ^SQLite guarantees that the zFilename parameter to xOpen
790** is either a NULL pointer or string obtained
791** from xFullPathname() with an optional suffix added.
792** ^If a suffix is added to the zFilename parameter, it will
793** consist of a single "-" character followed by no more than
794** 10 alphanumeric and/or "-" characters.
795** ^SQLite further guarantees that
796** the string will be valid and unchanged until xClose() is
797** called. Because of the previous sentence,
798** the [sqlite3_file] can safely store a pointer to the
799** filename if it needs to remember the filename for some reason.
800** If the zFilename parameter to xOpen is a NULL pointer then xOpen
801** must invent its own temporary name for the file.  ^Whenever the
802** xFilename parameter is NULL it will also be the case that the
803** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
804**
805** The flags argument to xOpen() includes all bits set in
806** the flags argument to [sqlite3_open_v2()].  Or if [sqlite3_open()]
807** or [sqlite3_open16()] is used, then flags includes at least
808** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE].
809** If xOpen() opens a file read-only then it sets *pOutFlags to
810** include [SQLITE_OPEN_READONLY].  Other bits in *pOutFlags may be set.
811**
812** ^(SQLite will also add one of the following flags to the xOpen()
813** call, depending on the object being opened:
814**
815** <ul>
816** <li>  [SQLITE_OPEN_MAIN_DB]
817** <li>  [SQLITE_OPEN_MAIN_JOURNAL]
818** <li>  [SQLITE_OPEN_TEMP_DB]
819** <li>  [SQLITE_OPEN_TEMP_JOURNAL]
820** <li>  [SQLITE_OPEN_TRANSIENT_DB]
821** <li>  [SQLITE_OPEN_SUBJOURNAL]
822** <li>  [SQLITE_OPEN_MASTER_JOURNAL]
823** <li>  [SQLITE_OPEN_WAL]
824** </ul>)^
825**
826** The file I/O implementation can use the object type flags to
827** change the way it deals with files.  For example, an application
828** that does not care about crash recovery or rollback might make
829** the open of a journal file a no-op.  Writes to this journal would
830** also be no-ops, and any attempt to read the journal would return
831** SQLITE_IOERR.  Or the implementation might recognize that a database
832** file will be doing page-aligned sector reads and writes in a random
833** order and set up its I/O subsystem accordingly.
834**
835** SQLite might also add one of the following flags to the xOpen method:
836**
837** <ul>
838** <li> [SQLITE_OPEN_DELETEONCLOSE]
839** <li> [SQLITE_OPEN_EXCLUSIVE]
840** </ul>
841**
842** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
843** deleted when it is closed.  ^The [SQLITE_OPEN_DELETEONCLOSE]
844** will be set for TEMP databases and their journals, transient
845** databases, and subjournals.
846**
847** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
848** with the [SQLITE_OPEN_CREATE] flag, which are both directly
849** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
850** API.  The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
851** SQLITE_OPEN_CREATE, is used to indicate that file should always
852** be created, and that it is an error if it already exists.
853** It is <i>not</i> used to indicate the file should be opened
854** for exclusive access.
855**
856** ^At least szOsFile bytes of memory are allocated by SQLite
857** to hold the  [sqlite3_file] structure passed as the third
858** argument to xOpen.  The xOpen method does not have to
859** allocate the structure; it should just fill it in.  Note that
860** the xOpen method must set the sqlite3_file.pMethods to either
861** a valid [sqlite3_io_methods] object or to NULL.  xOpen must do
862** this even if the open fails.  SQLite expects that the sqlite3_file.pMethods
863** element will be valid after xOpen returns regardless of the success
864** or failure of the xOpen call.
865**
866** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
867** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
868** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
869** to test whether a file is at least readable.   The file can be a
870** directory.
871**
872** ^SQLite will always allocate at least mxPathname+1 bytes for the
873** output buffer xFullPathname.  The exact size of the output buffer
874** is also passed as a parameter to both  methods. If the output buffer
875** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
876** handled as a fatal error by SQLite, vfs implementations should endeavor
877** to prevent this by setting mxPathname to a sufficiently large value.
878**
879** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
880** interfaces are not strictly a part of the filesystem, but they are
881** included in the VFS structure for completeness.
882** The xRandomness() function attempts to return nBytes bytes
883** of good-quality randomness into zOut.  The return value is
884** the actual number of bytes of randomness obtained.
885** The xSleep() method causes the calling thread to sleep for at
886** least the number of microseconds given.  ^The xCurrentTime()
887** method returns a Julian Day Number for the current date and time as
888** a floating point value.
889** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
890** Day Number multipled by 86400000 (the number of milliseconds in
891** a 24-hour day).
892** ^SQLite will use the xCurrentTimeInt64() method to get the current
893** date and time if that method is available (if iVersion is 2 or
894** greater and the function pointer is not NULL) and will fall back
895** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
896**
897** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
898** are not used by the SQLite core.  These optional interfaces are provided
899** by some VFSes to facilitate testing of the VFS code. By overriding
900** system calls with functions under its control, a test program can
901** simulate faults and error conditions that would otherwise be difficult
902** or impossible to induce.  The set of system calls that can be overridden
903** varies from one VFS to another, and from one version of the same VFS to the
904** next.  Applications that use these interfaces must be prepared for any
905** or all of these interfaces to be NULL or for their behavior to change
906** from one release to the next.  Applications must not attempt to access
907** any of these methods if the iVersion of the VFS is less than 3.
908*/
909typedef struct sqlite3_vfs sqlite3_vfs;
910typedef void (*sqlite3_syscall_ptr)(void);
911struct sqlite3_vfs {
912  int iVersion;            /* Structure version number (currently 3) */
913  int szOsFile;            /* Size of subclassed sqlite3_file */
914  int mxPathname;          /* Maximum file pathname length */
915  sqlite3_vfs *pNext;      /* Next registered VFS */
916  const char *zName;       /* Name of this virtual file system */
917  void *pAppData;          /* Pointer to application-specific data */
918  int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
919               int flags, int *pOutFlags);
920  int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
921  int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
922  int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
923  void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
924  void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
925  void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
926  void (*xDlClose)(sqlite3_vfs*, void*);
927  int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
928  int (*xSleep)(sqlite3_vfs*, int microseconds);
929  int (*xCurrentTime)(sqlite3_vfs*, double*);
930  int (*xGetLastError)(sqlite3_vfs*, int, char *);
931  /*
932  ** The methods above are in version 1 of the sqlite_vfs object
933  ** definition.  Those that follow are added in version 2 or later
934  */
935  int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
936  /*
937  ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
938  ** Those below are for version 3 and greater.
939  */
940  int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
941  sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
942  const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
943  /*
944  ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
945  ** New fields may be appended in figure versions.  The iVersion
946  ** value will increment whenever this happens.
947  */
948};
949
950/*
951** CAPI3REF: Flags for the xAccess VFS method
952**
953** These integer constants can be used as the third parameter to
954** the xAccess method of an [sqlite3_vfs] object.  They determine
955** what kind of permissions the xAccess method is looking for.
956** With SQLITE_ACCESS_EXISTS, the xAccess method
957** simply checks whether the file exists.
958** With SQLITE_ACCESS_READWRITE, the xAccess method
959** checks whether the named directory is both readable and writable
960** (in other words, if files can be added, removed, and renamed within
961** the directory).
962** The SQLITE_ACCESS_READWRITE constant is currently used only by the
963** [temp_store_directory pragma], though this could change in a future
964** release of SQLite.
965** With SQLITE_ACCESS_READ, the xAccess method
966** checks whether the file is readable.  The SQLITE_ACCESS_READ constant is
967** currently unused, though it might be used in a future release of
968** SQLite.
969*/
970#define SQLITE_ACCESS_EXISTS    0
971#define SQLITE_ACCESS_READWRITE 1   /* Used by PRAGMA temp_store_directory */
972#define SQLITE_ACCESS_READ      2   /* Unused */
973
974/*
975** CAPI3REF: Flags for the xShmLock VFS method
976**
977** These integer constants define the various locking operations
978** allowed by the xShmLock method of [sqlite3_io_methods].  The
979** following are the only legal combinations of flags to the
980** xShmLock method:
981**
982** <ul>
983** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
984** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
985** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
986** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
987** </ul>
988**
989** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
990** was given no the corresponding lock.
991**
992** The xShmLock method can transition between unlocked and SHARED or
993** between unlocked and EXCLUSIVE.  It cannot transition between SHARED
994** and EXCLUSIVE.
995*/
996#define SQLITE_SHM_UNLOCK       1
997#define SQLITE_SHM_LOCK         2
998#define SQLITE_SHM_SHARED       4
999#define SQLITE_SHM_EXCLUSIVE    8
1000
1001/*
1002** CAPI3REF: Maximum xShmLock index
1003**
1004** The xShmLock method on [sqlite3_io_methods] may use values
1005** between 0 and this upper bound as its "offset" argument.
1006** The SQLite core will never attempt to acquire or release a
1007** lock outside of this range
1008*/
1009#define SQLITE_SHM_NLOCK        8
1010
1011
1012/*
1013** CAPI3REF: Initialize The SQLite Library
1014**
1015** ^The sqlite3_initialize() routine initializes the
1016** SQLite library.  ^The sqlite3_shutdown() routine
1017** deallocates any resources that were allocated by sqlite3_initialize().
1018** These routines are designed to aid in process initialization and
1019** shutdown on embedded systems.  Workstation applications using
1020** SQLite normally do not need to invoke either of these routines.
1021**
1022** A call to sqlite3_initialize() is an "effective" call if it is
1023** the first time sqlite3_initialize() is invoked during the lifetime of
1024** the process, or if it is the first time sqlite3_initialize() is invoked
1025** following a call to sqlite3_shutdown().  ^(Only an effective call
1026** of sqlite3_initialize() does any initialization.  All other calls
1027** are harmless no-ops.)^
1028**
1029** A call to sqlite3_shutdown() is an "effective" call if it is the first
1030** call to sqlite3_shutdown() since the last sqlite3_initialize().  ^(Only
1031** an effective call to sqlite3_shutdown() does any deinitialization.
1032** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
1033**
1034** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
1035** is not.  The sqlite3_shutdown() interface must only be called from a
1036** single thread.  All open [database connections] must be closed and all
1037** other SQLite resources must be deallocated prior to invoking
1038** sqlite3_shutdown().
1039**
1040** Among other things, ^sqlite3_initialize() will invoke
1041** sqlite3_os_init().  Similarly, ^sqlite3_shutdown()
1042** will invoke sqlite3_os_end().
1043**
1044** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
1045** ^If for some reason, sqlite3_initialize() is unable to initialize
1046** the library (perhaps it is unable to allocate a needed resource such
1047** as a mutex) it returns an [error code] other than [SQLITE_OK].
1048**
1049** ^The sqlite3_initialize() routine is called internally by many other
1050** SQLite interfaces so that an application usually does not need to
1051** invoke sqlite3_initialize() directly.  For example, [sqlite3_open()]
1052** calls sqlite3_initialize() so the SQLite library will be automatically
1053** initialized when [sqlite3_open()] is called if it has not be initialized
1054** already.  ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
1055** compile-time option, then the automatic calls to sqlite3_initialize()
1056** are omitted and the application must call sqlite3_initialize() directly
1057** prior to using any other SQLite interface.  For maximum portability,
1058** it is recommended that applications always invoke sqlite3_initialize()
1059** directly prior to using any other SQLite interface.  Future releases
1060** of SQLite may require this.  In other words, the behavior exhibited
1061** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
1062** default behavior in some future release of SQLite.
1063**
1064** The sqlite3_os_init() routine does operating-system specific
1065** initialization of the SQLite library.  The sqlite3_os_end()
1066** routine undoes the effect of sqlite3_os_init().  Typical tasks
1067** performed by these routines include allocation or deallocation
1068** of static resources, initialization of global variables,
1069** setting up a default [sqlite3_vfs] module, or setting up
1070** a default configuration using [sqlite3_config()].
1071**
1072** The application should never invoke either sqlite3_os_init()
1073** or sqlite3_os_end() directly.  The application should only invoke
1074** sqlite3_initialize() and sqlite3_shutdown().  The sqlite3_os_init()
1075** interface is called automatically by sqlite3_initialize() and
1076** sqlite3_os_end() is called by sqlite3_shutdown().  Appropriate
1077** implementations for sqlite3_os_init() and sqlite3_os_end()
1078** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
1079** When [custom builds | built for other platforms]
1080** (using the [SQLITE_OS_OTHER=1] compile-time
1081** option) the application must supply a suitable implementation for
1082** sqlite3_os_init() and sqlite3_os_end().  An application-supplied
1083** implementation of sqlite3_os_init() or sqlite3_os_end()
1084** must return [SQLITE_OK] on success and some other [error code] upon
1085** failure.
1086*/
1087int sqlite3_initialize(void);
1088int sqlite3_shutdown(void);
1089int sqlite3_os_init(void);
1090int sqlite3_os_end(void);
1091
1092/*
1093** CAPI3REF: Configuring The SQLite Library
1094**
1095** The sqlite3_config() interface is used to make global configuration
1096** changes to SQLite in order to tune SQLite to the specific needs of
1097** the application.  The default configuration is recommended for most
1098** applications and so this routine is usually not necessary.  It is
1099** provided to support rare applications with unusual needs.
1100**
1101** The sqlite3_config() interface is not threadsafe.  The application
1102** must insure that no other SQLite interfaces are invoked by other
1103** threads while sqlite3_config() is running.  Furthermore, sqlite3_config()
1104** may only be invoked prior to library initialization using
1105** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
1106** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
1107** [sqlite3_shutdown()] then it will return SQLITE_MISUSE.
1108** Note, however, that ^sqlite3_config() can be called as part of the
1109** implementation of an application-defined [sqlite3_os_init()].
1110**
1111** The first argument to sqlite3_config() is an integer
1112** [SQLITE_CONFIG_SINGLETHREAD | configuration option] that determines
1113** what property of SQLite is to be configured.  Subsequent arguments
1114** vary depending on the [SQLITE_CONFIG_SINGLETHREAD | configuration option]
1115** in the first argument.
1116**
1117** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
1118** ^If the option is unknown or SQLite is unable to set the option
1119** then this routine returns a non-zero [error code].
1120*/
1121int sqlite3_config(int, ...);
1122
1123/*
1124** CAPI3REF: Configure database connections
1125**
1126** The sqlite3_db_config() interface is used to make configuration
1127** changes to a [database connection].  The interface is similar to
1128** [sqlite3_config()] except that the changes apply to a single
1129** [database connection] (specified in the first argument).
1130**
1131** The second argument to sqlite3_db_config(D,V,...)  is the
1132** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code
1133** that indicates what aspect of the [database connection] is being configured.
1134** Subsequent arguments vary depending on the configuration verb.
1135**
1136** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
1137** the call is considered successful.
1138*/
1139int sqlite3_db_config(sqlite3*, int op, ...);
1140
1141/*
1142** CAPI3REF: Memory Allocation Routines
1143**
1144** An instance of this object defines the interface between SQLite
1145** and low-level memory allocation routines.
1146**
1147** This object is used in only one place in the SQLite interface.
1148** A pointer to an instance of this object is the argument to
1149** [sqlite3_config()] when the configuration option is
1150** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].
1151** By creating an instance of this object
1152** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
1153** during configuration, an application can specify an alternative
1154** memory allocation subsystem for SQLite to use for all of its
1155** dynamic memory needs.
1156**
1157** Note that SQLite comes with several [built-in memory allocators]
1158** that are perfectly adequate for the overwhelming majority of applications
1159** and that this object is only useful to a tiny minority of applications
1160** with specialized memory allocation requirements.  This object is
1161** also used during testing of SQLite in order to specify an alternative
1162** memory allocator that simulates memory out-of-memory conditions in
1163** order to verify that SQLite recovers gracefully from such
1164** conditions.
1165**
1166** The xMalloc and xFree methods must work like the
1167** malloc() and free() functions from the standard C library.
1168** The xRealloc method must work like realloc() from the standard C library
1169** with the exception that if the second argument to xRealloc is zero,
1170** xRealloc must be a no-op - it must not perform any allocation or
1171** deallocation.  ^SQLite guarantees that the second argument to
1172** xRealloc is always a value returned by a prior call to xRoundup.
1173** And so in cases where xRoundup always returns a positive number,
1174** xRealloc can perform exactly as the standard library realloc() and
1175** still be in compliance with this specification.
1176**
1177** xSize should return the allocated size of a memory allocation
1178** previously obtained from xMalloc or xRealloc.  The allocated size
1179** is always at least as big as the requested size but may be larger.
1180**
1181** The xRoundup method returns what would be the allocated size of
1182** a memory allocation given a particular requested size.  Most memory
1183** allocators round up memory allocations at least to the next multiple
1184** of 8.  Some allocators round up to a larger multiple or to a power of 2.
1185** Every memory allocation request coming in through [sqlite3_malloc()]
1186** or [sqlite3_realloc()] first calls xRoundup.  If xRoundup returns 0,
1187** that causes the corresponding memory allocation to fail.
1188**
1189** The xInit method initializes the memory allocator.  (For example,
1190** it might allocate any require mutexes or initialize internal data
1191** structures.  The xShutdown method is invoked (indirectly) by
1192** [sqlite3_shutdown()] and should deallocate any resources acquired
1193** by xInit.  The pAppData pointer is used as the only parameter to
1194** xInit and xShutdown.
1195**
1196** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes
1197** the xInit method, so the xInit method need not be threadsafe.  The
1198** xShutdown method is only called from [sqlite3_shutdown()] so it does
1199** not need to be threadsafe either.  For all other methods, SQLite
1200** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
1201** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
1202** it is by default) and so the methods are automatically serialized.
1203** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
1204** methods must be threadsafe or else make their own arrangements for
1205** serialization.
1206**
1207** SQLite will never invoke xInit() more than once without an intervening
1208** call to xShutdown().
1209*/
1210typedef struct sqlite3_mem_methods sqlite3_mem_methods;
1211struct sqlite3_mem_methods {
1212  void *(*xMalloc)(int);         /* Memory allocation function */
1213  void (*xFree)(void*);          /* Free a prior allocation */
1214  void *(*xRealloc)(void*,int);  /* Resize an allocation */
1215  int (*xSize)(void*);           /* Return the size of an allocation */
1216  int (*xRoundup)(int);          /* Round up request size to allocation size */
1217  int (*xInit)(void*);           /* Initialize the memory allocator */
1218  void (*xShutdown)(void*);      /* Deinitialize the memory allocator */
1219  void *pAppData;                /* Argument to xInit() and xShutdown() */
1220};
1221
1222/*
1223** CAPI3REF: Configuration Options
1224**
1225** These constants are the available integer configuration options that
1226** can be passed as the first argument to the [sqlite3_config()] interface.
1227**
1228** New configuration options may be added in future releases of SQLite.
1229** Existing configuration options might be discontinued.  Applications
1230** should check the return code from [sqlite3_config()] to make sure that
1231** the call worked.  The [sqlite3_config()] interface will return a
1232** non-zero [error code] if a discontinued or unsupported configuration option
1233** is invoked.
1234**
1235** <dl>
1236** <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
1237** <dd>There are no arguments to this option.  ^This option sets the
1238** [threading mode] to Single-thread.  In other words, it disables
1239** all mutexing and puts SQLite into a mode where it can only be used
1240** by a single thread.   ^If SQLite is compiled with
1241** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1242** it is not possible to change the [threading mode] from its default
1243** value of Single-thread and so [sqlite3_config()] will return
1244** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
1245** configuration option.</dd>
1246**
1247** <dt>SQLITE_CONFIG_MULTITHREAD</dt>
1248** <dd>There are no arguments to this option.  ^This option sets the
1249** [threading mode] to Multi-thread.  In other words, it disables
1250** mutexing on [database connection] and [prepared statement] objects.
1251** The application is responsible for serializing access to
1252** [database connections] and [prepared statements].  But other mutexes
1253** are enabled so that SQLite will be safe to use in a multi-threaded
1254** environment as long as no two threads attempt to use the same
1255** [database connection] at the same time.  ^If SQLite is compiled with
1256** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1257** it is not possible to set the Multi-thread [threading mode] and
1258** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1259** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
1260**
1261** <dt>SQLITE_CONFIG_SERIALIZED</dt>
1262** <dd>There are no arguments to this option.  ^This option sets the
1263** [threading mode] to Serialized. In other words, this option enables
1264** all mutexes including the recursive
1265** mutexes on [database connection] and [prepared statement] objects.
1266** In this mode (which is the default when SQLite is compiled with
1267** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
1268** to [database connections] and [prepared statements] so that the
1269** application is free to use the same [database connection] or the
1270** same [prepared statement] in different threads at the same time.
1271** ^If SQLite is compiled with
1272** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1273** it is not possible to set the Serialized [threading mode] and
1274** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1275** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
1276**
1277** <dt>SQLITE_CONFIG_MALLOC</dt>
1278** <dd> ^(This option takes a single argument which is a pointer to an
1279** instance of the [sqlite3_mem_methods] structure.  The argument specifies
1280** alternative low-level memory allocation routines to be used in place of
1281** the memory allocation routines built into SQLite.)^ ^SQLite makes
1282** its own private copy of the content of the [sqlite3_mem_methods] structure
1283** before the [sqlite3_config()] call returns.</dd>
1284**
1285** <dt>SQLITE_CONFIG_GETMALLOC</dt>
1286** <dd> ^(This option takes a single argument which is a pointer to an
1287** instance of the [sqlite3_mem_methods] structure.  The [sqlite3_mem_methods]
1288** structure is filled with the currently defined memory allocation routines.)^
1289** This option can be used to overload the default memory allocation
1290** routines with a wrapper that simulations memory allocation failure or
1291** tracks memory usage, for example. </dd>
1292**
1293** <dt>SQLITE_CONFIG_MEMSTATUS</dt>
1294** <dd> ^This option takes single argument of type int, interpreted as a
1295** boolean, which enables or disables the collection of memory allocation
1296** statistics. ^(When memory allocation statistics are disabled, the
1297** following SQLite interfaces become non-operational:
1298**   <ul>
1299**   <li> [sqlite3_memory_used()]
1300**   <li> [sqlite3_memory_highwater()]
1301**   <li> [sqlite3_soft_heap_limit64()]
1302**   <li> [sqlite3_status()]
1303**   </ul>)^
1304** ^Memory allocation statistics are enabled by default unless SQLite is
1305** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
1306** allocation statistics are disabled by default.
1307** </dd>
1308**
1309** <dt>SQLITE_CONFIG_SCRATCH</dt>
1310** <dd> ^This option specifies a static memory buffer that SQLite can use for
1311** scratch memory.  There are three arguments:  A pointer an 8-byte
1312** aligned memory buffer from which the scratch allocations will be
1313** drawn, the size of each scratch allocation (sz),
1314** and the maximum number of scratch allocations (N).  The sz
1315** argument must be a multiple of 16.
1316** The first argument must be a pointer to an 8-byte aligned buffer
1317** of at least sz*N bytes of memory.
1318** ^SQLite will use no more than two scratch buffers per thread.  So
1319** N should be set to twice the expected maximum number of threads.
1320** ^SQLite will never require a scratch buffer that is more than 6
1321** times the database page size. ^If SQLite needs needs additional
1322** scratch memory beyond what is provided by this configuration option, then
1323** [sqlite3_malloc()] will be used to obtain the memory needed.</dd>
1324**
1325** <dt>SQLITE_CONFIG_PAGECACHE</dt>
1326** <dd> ^This option specifies a static memory buffer that SQLite can use for
1327** the database page cache with the default page cache implemenation.
1328** This configuration should not be used if an application-define page
1329** cache implementation is loaded using the SQLITE_CONFIG_PCACHE option.
1330** There are three arguments to this option: A pointer to 8-byte aligned
1331** memory, the size of each page buffer (sz), and the number of pages (N).
1332** The sz argument should be the size of the largest database page
1333** (a power of two between 512 and 32768) plus a little extra for each
1334** page header.  ^The page header size is 20 to 40 bytes depending on
1335** the host architecture.  ^It is harmless, apart from the wasted memory,
1336** to make sz a little too large.  The first
1337** argument should point to an allocation of at least sz*N bytes of memory.
1338** ^SQLite will use the memory provided by the first argument to satisfy its
1339** memory needs for the first N pages that it adds to cache.  ^If additional
1340** page cache memory is needed beyond what is provided by this option, then
1341** SQLite goes to [sqlite3_malloc()] for the additional storage space.
1342** The pointer in the first argument must
1343** be aligned to an 8-byte boundary or subsequent behavior of SQLite
1344** will be undefined.</dd>
1345**
1346** <dt>SQLITE_CONFIG_HEAP</dt>
1347** <dd> ^This option specifies a static memory buffer that SQLite will use
1348** for all of its dynamic memory allocation needs beyond those provided
1349** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE].
1350** There are three arguments: An 8-byte aligned pointer to the memory,
1351** the number of bytes in the memory buffer, and the minimum allocation size.
1352** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
1353** to using its default memory allocator (the system malloc() implementation),
1354** undoing any prior invocation of [SQLITE_CONFIG_MALLOC].  ^If the
1355** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or
1356** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory
1357** allocator is engaged to handle all of SQLites memory allocation needs.
1358** The first pointer (the memory pointer) must be aligned to an 8-byte
1359** boundary or subsequent behavior of SQLite will be undefined.
1360** The minimum allocation size is capped at 2^12. Reasonable values
1361** for the minimum allocation size are 2^5 through 2^8.</dd>
1362**
1363** <dt>SQLITE_CONFIG_MUTEX</dt>
1364** <dd> ^(This option takes a single argument which is a pointer to an
1365** instance of the [sqlite3_mutex_methods] structure.  The argument specifies
1366** alternative low-level mutex routines to be used in place
1367** the mutex routines built into SQLite.)^  ^SQLite makes a copy of the
1368** content of the [sqlite3_mutex_methods] structure before the call to
1369** [sqlite3_config()] returns. ^If SQLite is compiled with
1370** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1371** the entire mutexing subsystem is omitted from the build and hence calls to
1372** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
1373** return [SQLITE_ERROR].</dd>
1374**
1375** <dt>SQLITE_CONFIG_GETMUTEX</dt>
1376** <dd> ^(This option takes a single argument which is a pointer to an
1377** instance of the [sqlite3_mutex_methods] structure.  The
1378** [sqlite3_mutex_methods]
1379** structure is filled with the currently defined mutex routines.)^
1380** This option can be used to overload the default mutex allocation
1381** routines with a wrapper used to track mutex usage for performance
1382** profiling or testing, for example.   ^If SQLite is compiled with
1383** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1384** the entire mutexing subsystem is omitted from the build and hence calls to
1385** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
1386** return [SQLITE_ERROR].</dd>
1387**
1388** <dt>SQLITE_CONFIG_LOOKASIDE</dt>
1389** <dd> ^(This option takes two arguments that determine the default
1390** memory allocation for the lookaside memory allocator on each
1391** [database connection].  The first argument is the
1392** size of each lookaside buffer slot and the second is the number of
1393** slots allocated to each database connection.)^  ^(This option sets the
1394** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
1395** verb to [sqlite3_db_config()] can be used to change the lookaside
1396** configuration on individual connections.)^ </dd>
1397**
1398** <dt>SQLITE_CONFIG_PCACHE</dt>
1399** <dd> ^(This option takes a single argument which is a pointer to
1400** an [sqlite3_pcache_methods] object.  This object specifies the interface
1401** to a custom page cache implementation.)^  ^SQLite makes a copy of the
1402** object and uses it for page cache memory allocations.</dd>
1403**
1404** <dt>SQLITE_CONFIG_GETPCACHE</dt>
1405** <dd> ^(This option takes a single argument which is a pointer to an
1406** [sqlite3_pcache_methods] object.  SQLite copies of the current
1407** page cache implementation into that object.)^ </dd>
1408**
1409** <dt>SQLITE_CONFIG_LOG</dt>
1410** <dd> ^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
1411** function with a call signature of void(*)(void*,int,const char*),
1412** and a pointer to void. ^If the function pointer is not NULL, it is
1413** invoked by [sqlite3_log()] to process each logging event.  ^If the
1414** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
1415** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
1416** passed through as the first parameter to the application-defined logger
1417** function whenever that function is invoked.  ^The second parameter to
1418** the logger function is a copy of the first parameter to the corresponding
1419** [sqlite3_log()] call and is intended to be a [result code] or an
1420** [extended result code].  ^The third parameter passed to the logger is
1421** log message after formatting via [sqlite3_snprintf()].
1422** The SQLite logging interface is not reentrant; the logger function
1423** supplied by the application must not invoke any SQLite interface.
1424** In a multi-threaded application, the application-defined logger
1425** function must be threadsafe. </dd>
1426**
1427** </dl>
1428*/
1429#define SQLITE_CONFIG_SINGLETHREAD  1  /* nil */
1430#define SQLITE_CONFIG_MULTITHREAD   2  /* nil */
1431#define SQLITE_CONFIG_SERIALIZED    3  /* nil */
1432#define SQLITE_CONFIG_MALLOC        4  /* sqlite3_mem_methods* */
1433#define SQLITE_CONFIG_GETMALLOC     5  /* sqlite3_mem_methods* */
1434#define SQLITE_CONFIG_SCRATCH       6  /* void*, int sz, int N */
1435#define SQLITE_CONFIG_PAGECACHE     7  /* void*, int sz, int N */
1436#define SQLITE_CONFIG_HEAP          8  /* void*, int nByte, int min */
1437#define SQLITE_CONFIG_MEMSTATUS     9  /* boolean */
1438#define SQLITE_CONFIG_MUTEX        10  /* sqlite3_mutex_methods* */
1439#define SQLITE_CONFIG_GETMUTEX     11  /* sqlite3_mutex_methods* */
1440/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */
1441#define SQLITE_CONFIG_LOOKASIDE    13  /* int int */
1442#define SQLITE_CONFIG_PCACHE       14  /* sqlite3_pcache_methods* */
1443#define SQLITE_CONFIG_GETPCACHE    15  /* sqlite3_pcache_methods* */
1444#define SQLITE_CONFIG_LOG          16  /* xFunc, void* */
1445
1446/*
1447** CAPI3REF: Database Connection Configuration Options
1448**
1449** These constants are the available integer configuration options that
1450** can be passed as the second argument to the [sqlite3_db_config()] interface.
1451**
1452** New configuration options may be added in future releases of SQLite.
1453** Existing configuration options might be discontinued.  Applications
1454** should check the return code from [sqlite3_db_config()] to make sure that
1455** the call worked.  ^The [sqlite3_db_config()] interface will return a
1456** non-zero [error code] if a discontinued or unsupported configuration option
1457** is invoked.
1458**
1459** <dl>
1460** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
1461** <dd> ^This option takes three additional arguments that determine the
1462** [lookaside memory allocator] configuration for the [database connection].
1463** ^The first argument (the third parameter to [sqlite3_db_config()] is a
1464** pointer to a memory buffer to use for lookaside memory.
1465** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
1466** may be NULL in which case SQLite will allocate the
1467** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
1468** size of each lookaside buffer slot.  ^The third argument is the number of
1469** slots.  The size of the buffer in the first argument must be greater than
1470** or equal to the product of the second and third arguments.  The buffer
1471** must be aligned to an 8-byte boundary.  ^If the second argument to
1472** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
1473** rounded down to the next smaller multiple of 8.  ^(The lookaside memory
1474** configuration for a database connection can only be changed when that
1475** connection is not currently using lookaside memory, or in other words
1476** when the "current value" returned by
1477** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero.
1478** Any attempt to change the lookaside memory configuration when lookaside
1479** memory is in use leaves the configuration unchanged and returns
1480** [SQLITE_BUSY].)^</dd>
1481**
1482** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
1483** <dd> ^This option is used to enable or disable the enforcement of
1484** [foreign key constraints].  There should be two additional arguments.
1485** The first argument is an integer which is 0 to disable FK enforcement,
1486** positive to enable FK enforcement or negative to leave FK enforcement
1487** unchanged.  The second parameter is a pointer to an integer into which
1488** is written 0 or 1 to indicate whether FK enforcement is off or on
1489** following this call.  The second parameter may be a NULL pointer, in
1490** which case the FK enforcement setting is not reported back. </dd>
1491**
1492** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
1493** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
1494** There should be two additional arguments.
1495** The first argument is an integer which is 0 to disable triggers,
1496** positive to enable triggers or negative to leave the setting unchanged.
1497** The second parameter is a pointer to an integer into which
1498** is written 0 or 1 to indicate whether triggers are disabled or enabled
1499** following this call.  The second parameter may be a NULL pointer, in
1500** which case the trigger setting is not reported back. </dd>
1501**
1502** </dl>
1503*/
1504#define SQLITE_DBCONFIG_LOOKASIDE       1001  /* void* int int */
1505#define SQLITE_DBCONFIG_ENABLE_FKEY     1002  /* int int* */
1506#define SQLITE_DBCONFIG_ENABLE_TRIGGER  1003  /* int int* */
1507
1508
1509/*
1510** CAPI3REF: Enable Or Disable Extended Result Codes
1511**
1512** ^The sqlite3_extended_result_codes() routine enables or disables the
1513** [extended result codes] feature of SQLite. ^The extended result
1514** codes are disabled by default for historical compatibility.
1515*/
1516int sqlite3_extended_result_codes(sqlite3*, int onoff);
1517
1518/*
1519** CAPI3REF: Last Insert Rowid
1520**
1521** ^Each entry in an SQLite table has a unique 64-bit signed
1522** integer key called the [ROWID | "rowid"]. ^The rowid is always available
1523** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
1524** names are not also used by explicitly declared columns. ^If
1525** the table has a column of type [INTEGER PRIMARY KEY] then that column
1526** is another alias for the rowid.
1527**
1528** ^This routine returns the [rowid] of the most recent
1529** successful [INSERT] into the database from the [database connection]
1530** in the first argument.  ^If no successful [INSERT]s
1531** have ever occurred on that database connection, zero is returned.
1532**
1533** ^(If an [INSERT] occurs within a trigger, then the [rowid] of the inserted
1534** row is returned by this routine as long as the trigger is running.
1535** But once the trigger terminates, the value returned by this routine
1536** reverts to the last value inserted before the trigger fired.)^
1537**
1538** ^An [INSERT] that fails due to a constraint violation is not a
1539** successful [INSERT] and does not change the value returned by this
1540** routine.  ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
1541** and INSERT OR ABORT make no changes to the return value of this
1542** routine when their insertion fails.  ^(When INSERT OR REPLACE
1543** encounters a constraint violation, it does not fail.  The
1544** INSERT continues to completion after deleting rows that caused
1545** the constraint problem so INSERT OR REPLACE will always change
1546** the return value of this interface.)^
1547**
1548** ^For the purposes of this routine, an [INSERT] is considered to
1549** be successful even if it is subsequently rolled back.
1550**
1551** This function is accessible to SQL statements via the
1552** [last_insert_rowid() SQL function].
1553**
1554** If a separate thread performs a new [INSERT] on the same
1555** database connection while the [sqlite3_last_insert_rowid()]
1556** function is running and thus changes the last insert [rowid],
1557** then the value returned by [sqlite3_last_insert_rowid()] is
1558** unpredictable and might not equal either the old or the new
1559** last insert [rowid].
1560*/
1561sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
1562
1563/*
1564** CAPI3REF: Count The Number Of Rows Modified
1565**
1566** ^This function returns the number of database rows that were changed
1567** or inserted or deleted by the most recently completed SQL statement
1568** on the [database connection] specified by the first parameter.
1569** ^(Only changes that are directly specified by the [INSERT], [UPDATE],
1570** or [DELETE] statement are counted.  Auxiliary changes caused by
1571** triggers or [foreign key actions] are not counted.)^ Use the
1572** [sqlite3_total_changes()] function to find the total number of changes
1573** including changes caused by triggers and foreign key actions.
1574**
1575** ^Changes to a view that are simulated by an [INSTEAD OF trigger]
1576** are not counted.  Only real table changes are counted.
1577**
1578** ^(A "row change" is a change to a single row of a single table
1579** caused by an INSERT, DELETE, or UPDATE statement.  Rows that
1580** are changed as side effects of [REPLACE] constraint resolution,
1581** rollback, ABORT processing, [DROP TABLE], or by any other
1582** mechanisms do not count as direct row changes.)^
1583**
1584** A "trigger context" is a scope of execution that begins and
1585** ends with the script of a [CREATE TRIGGER | trigger].
1586** Most SQL statements are
1587** evaluated outside of any trigger.  This is the "top level"
1588** trigger context.  If a trigger fires from the top level, a
1589** new trigger context is entered for the duration of that one
1590** trigger.  Subtriggers create subcontexts for their duration.
1591**
1592** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does
1593** not create a new trigger context.
1594**
1595** ^This function returns the number of direct row changes in the
1596** most recent INSERT, UPDATE, or DELETE statement within the same
1597** trigger context.
1598**
1599** ^Thus, when called from the top level, this function returns the
1600** number of changes in the most recent INSERT, UPDATE, or DELETE
1601** that also occurred at the top level.  ^(Within the body of a trigger,
1602** the sqlite3_changes() interface can be called to find the number of
1603** changes in the most recently completed INSERT, UPDATE, or DELETE
1604** statement within the body of the same trigger.
1605** However, the number returned does not include changes
1606** caused by subtriggers since those have their own context.)^
1607**
1608** See also the [sqlite3_total_changes()] interface, the
1609** [count_changes pragma], and the [changes() SQL function].
1610**
1611** If a separate thread makes changes on the same database connection
1612** while [sqlite3_changes()] is running then the value returned
1613** is unpredictable and not meaningful.
1614*/
1615int sqlite3_changes(sqlite3*);
1616
1617/*
1618** CAPI3REF: Total Number Of Rows Modified
1619**
1620** ^This function returns the number of row changes caused by [INSERT],
1621** [UPDATE] or [DELETE] statements since the [database connection] was opened.
1622** ^(The count returned by sqlite3_total_changes() includes all changes
1623** from all [CREATE TRIGGER | trigger] contexts and changes made by
1624** [foreign key actions]. However,
1625** the count does not include changes used to implement [REPLACE] constraints,
1626** do rollbacks or ABORT processing, or [DROP TABLE] processing.  The
1627** count does not include rows of views that fire an [INSTEAD OF trigger],
1628** though if the INSTEAD OF trigger makes changes of its own, those changes
1629** are counted.)^
1630** ^The sqlite3_total_changes() function counts the changes as soon as
1631** the statement that makes them is completed (when the statement handle
1632** is passed to [sqlite3_reset()] or [sqlite3_finalize()]).
1633**
1634** See also the [sqlite3_changes()] interface, the
1635** [count_changes pragma], and the [total_changes() SQL function].
1636**
1637** If a separate thread makes changes on the same database connection
1638** while [sqlite3_total_changes()] is running then the value
1639** returned is unpredictable and not meaningful.
1640*/
1641int sqlite3_total_changes(sqlite3*);
1642
1643/*
1644** CAPI3REF: Interrupt A Long-Running Query
1645**
1646** ^This function causes any pending database operation to abort and
1647** return at its earliest opportunity. This routine is typically
1648** called in response to a user action such as pressing "Cancel"
1649** or Ctrl-C where the user wants a long query operation to halt
1650** immediately.
1651**
1652** ^It is safe to call this routine from a thread different from the
1653** thread that is currently running the database operation.  But it
1654** is not safe to call this routine with a [database connection] that
1655** is closed or might close before sqlite3_interrupt() returns.
1656**
1657** ^If an SQL operation is very nearly finished at the time when
1658** sqlite3_interrupt() is called, then it might not have an opportunity
1659** to be interrupted and might continue to completion.
1660**
1661** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
1662** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
1663** that is inside an explicit transaction, then the entire transaction
1664** will be rolled back automatically.
1665**
1666** ^The sqlite3_interrupt(D) call is in effect until all currently running
1667** SQL statements on [database connection] D complete.  ^Any new SQL statements
1668** that are started after the sqlite3_interrupt() call and before the
1669** running statements reaches zero are interrupted as if they had been
1670** running prior to the sqlite3_interrupt() call.  ^New SQL statements
1671** that are started after the running statement count reaches zero are
1672** not effected by the sqlite3_interrupt().
1673** ^A call to sqlite3_interrupt(D) that occurs when there are no running
1674** SQL statements is a no-op and has no effect on SQL statements
1675** that are started after the sqlite3_interrupt() call returns.
1676**
1677** If the database connection closes while [sqlite3_interrupt()]
1678** is running then bad things will likely happen.
1679*/
1680void sqlite3_interrupt(sqlite3*);
1681
1682/*
1683** CAPI3REF: Determine If An SQL Statement Is Complete
1684**
1685** These routines are useful during command-line input to determine if the
1686** currently entered text seems to form a complete SQL statement or
1687** if additional input is needed before sending the text into
1688** SQLite for parsing.  ^These routines return 1 if the input string
1689** appears to be a complete SQL statement.  ^A statement is judged to be
1690** complete if it ends with a semicolon token and is not a prefix of a
1691** well-formed CREATE TRIGGER statement.  ^Semicolons that are embedded within
1692** string literals or quoted identifier names or comments are not
1693** independent tokens (they are part of the token in which they are
1694** embedded) and thus do not count as a statement terminator.  ^Whitespace
1695** and comments that follow the final semicolon are ignored.
1696**
1697** ^These routines return 0 if the statement is incomplete.  ^If a
1698** memory allocation fails, then SQLITE_NOMEM is returned.
1699**
1700** ^These routines do not parse the SQL statements thus
1701** will not detect syntactically incorrect SQL.
1702**
1703** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior
1704** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
1705** automatically by sqlite3_complete16().  If that initialization fails,
1706** then the return value from sqlite3_complete16() will be non-zero
1707** regardless of whether or not the input SQL is complete.)^
1708**
1709** The input to [sqlite3_complete()] must be a zero-terminated
1710** UTF-8 string.
1711**
1712** The input to [sqlite3_complete16()] must be a zero-terminated
1713** UTF-16 string in native byte order.
1714*/
1715int sqlite3_complete(const char *sql);
1716int sqlite3_complete16(const void *sql);
1717
1718/*
1719** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
1720**
1721** ^This routine sets a callback function that might be invoked whenever
1722** an attempt is made to open a database table that another thread
1723** or process has locked.
1724**
1725** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]
1726** is returned immediately upon encountering the lock.  ^If the busy callback
1727** is not NULL, then the callback might be invoked with two arguments.
1728**
1729** ^The first argument to the busy handler is a copy of the void* pointer which
1730** is the third argument to sqlite3_busy_handler().  ^The second argument to
1731** the busy handler callback is the number of times that the busy handler has
1732** been invoked for this locking event.  ^If the
1733** busy callback returns 0, then no additional attempts are made to
1734** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned.
1735** ^If the callback returns non-zero, then another attempt
1736** is made to open the database for reading and the cycle repeats.
1737**
1738** The presence of a busy handler does not guarantee that it will be invoked
1739** when there is lock contention. ^If SQLite determines that invoking the busy
1740** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
1741** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler.
1742** Consider a scenario where one process is holding a read lock that
1743** it is trying to promote to a reserved lock and
1744** a second process is holding a reserved lock that it is trying
1745** to promote to an exclusive lock.  The first process cannot proceed
1746** because it is blocked by the second and the second process cannot
1747** proceed because it is blocked by the first.  If both processes
1748** invoke the busy handlers, neither will make any progress.  Therefore,
1749** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
1750** will induce the first process to release its read lock and allow
1751** the second process to proceed.
1752**
1753** ^The default busy callback is NULL.
1754**
1755** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED]
1756** when SQLite is in the middle of a large transaction where all the
1757** changes will not fit into the in-memory cache.  SQLite will
1758** already hold a RESERVED lock on the database file, but it needs
1759** to promote this lock to EXCLUSIVE so that it can spill cache
1760** pages into the database file without harm to concurrent
1761** readers.  ^If it is unable to promote the lock, then the in-memory
1762** cache will be left in an inconsistent state and so the error
1763** code is promoted from the relatively benign [SQLITE_BUSY] to
1764** the more severe [SQLITE_IOERR_BLOCKED].  ^This error code promotion
1765** forces an automatic rollback of the changes.  See the
1766** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError">
1767** CorruptionFollowingBusyError</a> wiki page for a discussion of why
1768** this is important.
1769**
1770** ^(There can only be a single busy handler defined for each
1771** [database connection].  Setting a new busy handler clears any
1772** previously set handler.)^  ^Note that calling [sqlite3_busy_timeout()]
1773** will also set or clear the busy handler.
1774**
1775** The busy callback should not take any actions which modify the
1776** database connection that invoked the busy handler.  Any such actions
1777** result in undefined behavior.
1778**
1779** A busy handler must not close the database connection
1780** or [prepared statement] that invoked the busy handler.
1781*/
1782int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*);
1783
1784/*
1785** CAPI3REF: Set A Busy Timeout
1786**
1787** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
1788** for a specified amount of time when a table is locked.  ^The handler
1789** will sleep multiple times until at least "ms" milliseconds of sleeping
1790** have accumulated.  ^After at least "ms" milliseconds of sleeping,
1791** the handler returns 0 which causes [sqlite3_step()] to return
1792** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED].
1793**
1794** ^Calling this routine with an argument less than or equal to zero
1795** turns off all busy handlers.
1796**
1797** ^(There can only be a single busy handler for a particular
1798** [database connection] any any given moment.  If another busy handler
1799** was defined  (using [sqlite3_busy_handler()]) prior to calling
1800** this routine, that other busy handler is cleared.)^
1801*/
1802int sqlite3_busy_timeout(sqlite3*, int ms);
1803
1804/*
1805** CAPI3REF: Convenience Routines For Running Queries
1806**
1807** This is a legacy interface that is preserved for backwards compatibility.
1808** Use of this interface is not recommended.
1809**
1810** Definition: A <b>result table</b> is memory data structure created by the
1811** [sqlite3_get_table()] interface.  A result table records the
1812** complete query results from one or more queries.
1813**
1814** The table conceptually has a number of rows and columns.  But
1815** these numbers are not part of the result table itself.  These
1816** numbers are obtained separately.  Let N be the number of rows
1817** and M be the number of columns.
1818**
1819** A result table is an array of pointers to zero-terminated UTF-8 strings.
1820** There are (N+1)*M elements in the array.  The first M pointers point
1821** to zero-terminated strings that  contain the names of the columns.
1822** The remaining entries all point to query results.  NULL values result
1823** in NULL pointers.  All other values are in their UTF-8 zero-terminated
1824** string representation as returned by [sqlite3_column_text()].
1825**
1826** A result table might consist of one or more memory allocations.
1827** It is not safe to pass a result table directly to [sqlite3_free()].
1828** A result table should be deallocated using [sqlite3_free_table()].
1829**
1830** ^(As an example of the result table format, suppose a query result
1831** is as follows:
1832**
1833** <blockquote><pre>
1834**        Name        | Age
1835**        -----------------------
1836**        Alice       | 43
1837**        Bob         | 28
1838**        Cindy       | 21
1839** </pre></blockquote>
1840**
1841** There are two column (M==2) and three rows (N==3).  Thus the
1842** result table has 8 entries.  Suppose the result table is stored
1843** in an array names azResult.  Then azResult holds this content:
1844**
1845** <blockquote><pre>
1846**        azResult&#91;0] = "Name";
1847**        azResult&#91;1] = "Age";
1848**        azResult&#91;2] = "Alice";
1849**        azResult&#91;3] = "43";
1850**        azResult&#91;4] = "Bob";
1851**        azResult&#91;5] = "28";
1852**        azResult&#91;6] = "Cindy";
1853**        azResult&#91;7] = "21";
1854** </pre></blockquote>)^
1855**
1856** ^The sqlite3_get_table() function evaluates one or more
1857** semicolon-separated SQL statements in the zero-terminated UTF-8
1858** string of its 2nd parameter and returns a result table to the
1859** pointer given in its 3rd parameter.
1860**
1861** After the application has finished with the result from sqlite3_get_table(),
1862** it must pass the result table pointer to sqlite3_free_table() in order to
1863** release the memory that was malloced.  Because of the way the
1864** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
1865** function must not try to call [sqlite3_free()] directly.  Only
1866** [sqlite3_free_table()] is able to release the memory properly and safely.
1867**
1868** The sqlite3_get_table() interface is implemented as a wrapper around
1869** [sqlite3_exec()].  The sqlite3_get_table() routine does not have access
1870** to any internal data structures of SQLite.  It uses only the public
1871** interface defined here.  As a consequence, errors that occur in the
1872** wrapper layer outside of the internal [sqlite3_exec()] call are not
1873** reflected in subsequent calls to [sqlite3_errcode()] or
1874** [sqlite3_errmsg()].
1875*/
1876int sqlite3_get_table(
1877  sqlite3 *db,          /* An open database */
1878  const char *zSql,     /* SQL to be evaluated */
1879  char ***pazResult,    /* Results of the query */
1880  int *pnRow,           /* Number of result rows written here */
1881  int *pnColumn,        /* Number of result columns written here */
1882  char **pzErrmsg       /* Error msg written here */
1883);
1884void sqlite3_free_table(char **result);
1885
1886/*
1887** CAPI3REF: Formatted String Printing Functions
1888**
1889** These routines are work-alikes of the "printf()" family of functions
1890** from the standard C library.
1891**
1892** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
1893** results into memory obtained from [sqlite3_malloc()].
1894** The strings returned by these two routines should be
1895** released by [sqlite3_free()].  ^Both routines return a
1896** NULL pointer if [sqlite3_malloc()] is unable to allocate enough
1897** memory to hold the resulting string.
1898**
1899** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
1900** the standard C library.  The result is written into the
1901** buffer supplied as the second parameter whose size is given by
1902** the first parameter. Note that the order of the
1903** first two parameters is reversed from snprintf().)^  This is an
1904** historical accident that cannot be fixed without breaking
1905** backwards compatibility.  ^(Note also that sqlite3_snprintf()
1906** returns a pointer to its buffer instead of the number of
1907** characters actually written into the buffer.)^  We admit that
1908** the number of characters written would be a more useful return
1909** value but we cannot change the implementation of sqlite3_snprintf()
1910** now without breaking compatibility.
1911**
1912** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
1913** guarantees that the buffer is always zero-terminated.  ^The first
1914** parameter "n" is the total size of the buffer, including space for
1915** the zero terminator.  So the longest string that can be completely
1916** written will be n-1 characters.
1917**
1918** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
1919**
1920** These routines all implement some additional formatting
1921** options that are useful for constructing SQL statements.
1922** All of the usual printf() formatting options apply.  In addition, there
1923** is are "%q", "%Q", and "%z" options.
1924**
1925** ^(The %q option works like %s in that it substitutes a null-terminated
1926** string from the argument list.  But %q also doubles every '\'' character.
1927** %q is designed for use inside a string literal.)^  By doubling each '\''
1928** character it escapes that character and allows it to be inserted into
1929** the string.
1930**
1931** For example, assume the string variable zText contains text as follows:
1932**
1933** <blockquote><pre>
1934**  char *zText = "It's a happy day!";
1935** </pre></blockquote>
1936**
1937** One can use this text in an SQL statement as follows:
1938**
1939** <blockquote><pre>
1940**  char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText);
1941**  sqlite3_exec(db, zSQL, 0, 0, 0);
1942**  sqlite3_free(zSQL);
1943** </pre></blockquote>
1944**
1945** Because the %q format string is used, the '\'' character in zText
1946** is escaped and the SQL generated is as follows:
1947**
1948** <blockquote><pre>
1949**  INSERT INTO table1 VALUES('It''s a happy day!')
1950** </pre></blockquote>
1951**
1952** This is correct.  Had we used %s instead of %q, the generated SQL
1953** would have looked like this:
1954**
1955** <blockquote><pre>
1956**  INSERT INTO table1 VALUES('It's a happy day!');
1957** </pre></blockquote>
1958**
1959** This second example is an SQL syntax error.  As a general rule you should
1960** always use %q instead of %s when inserting text into a string literal.
1961**
1962** ^(The %Q option works like %q except it also adds single quotes around
1963** the outside of the total string.  Additionally, if the parameter in the
1964** argument list is a NULL pointer, %Q substitutes the text "NULL" (without
1965** single quotes).)^  So, for example, one could say:
1966**
1967** <blockquote><pre>
1968**  char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText);
1969**  sqlite3_exec(db, zSQL, 0, 0, 0);
1970**  sqlite3_free(zSQL);
1971** </pre></blockquote>
1972**
1973** The code above will render a correct SQL statement in the zSQL
1974** variable even if the zText variable is a NULL pointer.
1975**
1976** ^(The "%z" formatting option works like "%s" but with the
1977** addition that after the string has been read and copied into
1978** the result, [sqlite3_free()] is called on the input string.)^
1979*/
1980char *sqlite3_mprintf(const char*,...);
1981char *sqlite3_vmprintf(const char*, va_list);
1982char *sqlite3_snprintf(int,char*,const char*, ...);
1983char *sqlite3_vsnprintf(int,char*,const char*, va_list);
1984
1985/*
1986** CAPI3REF: Memory Allocation Subsystem
1987**
1988** The SQLite core uses these three routines for all of its own
1989** internal memory allocation needs. "Core" in the previous sentence
1990** does not include operating-system specific VFS implementation.  The
1991** Windows VFS uses native malloc() and free() for some operations.
1992**
1993** ^The sqlite3_malloc() routine returns a pointer to a block
1994** of memory at least N bytes in length, where N is the parameter.
1995** ^If sqlite3_malloc() is unable to obtain sufficient free
1996** memory, it returns a NULL pointer.  ^If the parameter N to
1997** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
1998** a NULL pointer.
1999**
2000** ^Calling sqlite3_free() with a pointer previously returned
2001** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
2002** that it might be reused.  ^The sqlite3_free() routine is
2003** a no-op if is called with a NULL pointer.  Passing a NULL pointer
2004** to sqlite3_free() is harmless.  After being freed, memory
2005** should neither be read nor written.  Even reading previously freed
2006** memory might result in a segmentation fault or other severe error.
2007** Memory corruption, a segmentation fault, or other severe error
2008** might result if sqlite3_free() is called with a non-NULL pointer that
2009** was not obtained from sqlite3_malloc() or sqlite3_realloc().
2010**
2011** ^(The sqlite3_realloc() interface attempts to resize a
2012** prior memory allocation to be at least N bytes, where N is the
2013** second parameter.  The memory allocation to be resized is the first
2014** parameter.)^ ^ If the first parameter to sqlite3_realloc()
2015** is a NULL pointer then its behavior is identical to calling
2016** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc().
2017** ^If the second parameter to sqlite3_realloc() is zero or
2018** negative then the behavior is exactly the same as calling
2019** sqlite3_free(P) where P is the first parameter to sqlite3_realloc().
2020** ^sqlite3_realloc() returns a pointer to a memory allocation
2021** of at least N bytes in size or NULL if sufficient memory is unavailable.
2022** ^If M is the size of the prior allocation, then min(N,M) bytes
2023** of the prior allocation are copied into the beginning of buffer returned
2024** by sqlite3_realloc() and the prior allocation is freed.
2025** ^If sqlite3_realloc() returns NULL, then the prior allocation
2026** is not freed.
2027**
2028** ^The memory returned by sqlite3_malloc() and sqlite3_realloc()
2029** is always aligned to at least an 8 byte boundary, or to a
2030** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
2031** option is used.
2032**
2033** In SQLite version 3.5.0 and 3.5.1, it was possible to define
2034** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in
2035** implementation of these routines to be omitted.  That capability
2036** is no longer provided.  Only built-in memory allocators can be used.
2037**
2038** The Windows OS interface layer calls
2039** the system malloc() and free() directly when converting
2040** filenames between the UTF-8 encoding used by SQLite
2041** and whatever filename encoding is used by the particular Windows
2042** installation.  Memory allocation errors are detected, but
2043** they are reported back as [SQLITE_CANTOPEN] or
2044** [SQLITE_IOERR] rather than [SQLITE_NOMEM].
2045**
2046** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
2047** must be either NULL or else pointers obtained from a prior
2048** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
2049** not yet been released.
2050**
2051** The application must not read or write any part of
2052** a block of memory after it has been released using
2053** [sqlite3_free()] or [sqlite3_realloc()].
2054*/
2055void *sqlite3_malloc(int);
2056void *sqlite3_realloc(void*, int);
2057void sqlite3_free(void*);
2058
2059/*
2060** CAPI3REF: Memory Allocator Statistics
2061**
2062** SQLite provides these two interfaces for reporting on the status
2063** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
2064** routines, which form the built-in memory allocation subsystem.
2065**
2066** ^The [sqlite3_memory_used()] routine returns the number of bytes
2067** of memory currently outstanding (malloced but not freed).
2068** ^The [sqlite3_memory_highwater()] routine returns the maximum
2069** value of [sqlite3_memory_used()] since the high-water mark
2070** was last reset.  ^The values returned by [sqlite3_memory_used()] and
2071** [sqlite3_memory_highwater()] include any overhead
2072** added by SQLite in its implementation of [sqlite3_malloc()],
2073** but not overhead added by the any underlying system library
2074** routines that [sqlite3_malloc()] may call.
2075**
2076** ^The memory high-water mark is reset to the current value of
2077** [sqlite3_memory_used()] if and only if the parameter to
2078** [sqlite3_memory_highwater()] is true.  ^The value returned
2079** by [sqlite3_memory_highwater(1)] is the high-water mark
2080** prior to the reset.
2081*/
2082sqlite3_int64 sqlite3_memory_used(void);
2083sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
2084
2085/*
2086** CAPI3REF: Pseudo-Random Number Generator
2087**
2088** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
2089** select random [ROWID | ROWIDs] when inserting new records into a table that
2090** already uses the largest possible [ROWID].  The PRNG is also used for
2091** the build-in random() and randomblob() SQL functions.  This interface allows
2092** applications to access the same PRNG for other purposes.
2093**
2094** ^A call to this routine stores N bytes of randomness into buffer P.
2095**
2096** ^The first time this routine is invoked (either internally or by
2097** the application) the PRNG is seeded using randomness obtained
2098** from the xRandomness method of the default [sqlite3_vfs] object.
2099** ^On all subsequent invocations, the pseudo-randomness is generated
2100** internally and without recourse to the [sqlite3_vfs] xRandomness
2101** method.
2102*/
2103void sqlite3_randomness(int N, void *P);
2104
2105/*
2106** CAPI3REF: Compile-Time Authorization Callbacks
2107**
2108** ^This routine registers an authorizer callback with a particular
2109** [database connection], supplied in the first argument.
2110** ^The authorizer callback is invoked as SQL statements are being compiled
2111** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
2112** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()].  ^At various
2113** points during the compilation process, as logic is being created
2114** to perform various actions, the authorizer callback is invoked to
2115** see if those actions are allowed.  ^The authorizer callback should
2116** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
2117** specific action but allow the SQL statement to continue to be
2118** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
2119** rejected with an error.  ^If the authorizer callback returns
2120** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
2121** then the [sqlite3_prepare_v2()] or equivalent call that triggered
2122** the authorizer will fail with an error message.
2123**
2124** When the callback returns [SQLITE_OK], that means the operation
2125** requested is ok.  ^When the callback returns [SQLITE_DENY], the
2126** [sqlite3_prepare_v2()] or equivalent call that triggered the
2127** authorizer will fail with an error message explaining that
2128** access is denied.
2129**
2130** ^The first parameter to the authorizer callback is a copy of the third
2131** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
2132** to the callback is an integer [SQLITE_COPY | action code] that specifies
2133** the particular action to be authorized. ^The third through sixth parameters
2134** to the callback are zero-terminated strings that contain additional
2135** details about the action to be authorized.
2136**
2137** ^If the action code is [SQLITE_READ]
2138** and the callback returns [SQLITE_IGNORE] then the
2139** [prepared statement] statement is constructed to substitute
2140** a NULL value in place of the table column that would have
2141** been read if [SQLITE_OK] had been returned.  The [SQLITE_IGNORE]
2142** return can be used to deny an untrusted user access to individual
2143** columns of a table.
2144** ^If the action code is [SQLITE_DELETE] and the callback returns
2145** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
2146** [truncate optimization] is disabled and all rows are deleted individually.
2147**
2148** An authorizer is used when [sqlite3_prepare | preparing]
2149** SQL statements from an untrusted source, to ensure that the SQL statements
2150** do not try to access data they are not allowed to see, or that they do not
2151** try to execute malicious statements that damage the database.  For
2152** example, an application may allow a user to enter arbitrary
2153** SQL queries for evaluation by a database.  But the application does
2154** not want the user to be able to make arbitrary changes to the
2155** database.  An authorizer could then be put in place while the
2156** user-entered SQL is being [sqlite3_prepare | prepared] that
2157** disallows everything except [SELECT] statements.
2158**
2159** Applications that need to process SQL from untrusted sources
2160** might also consider lowering resource limits using [sqlite3_limit()]
2161** and limiting database size using the [max_page_count] [PRAGMA]
2162** in addition to using an authorizer.
2163**
2164** ^(Only a single authorizer can be in place on a database connection
2165** at a time.  Each call to sqlite3_set_authorizer overrides the
2166** previous call.)^  ^Disable the authorizer by installing a NULL callback.
2167** The authorizer is disabled by default.
2168**
2169** The authorizer callback must not do anything that will modify
2170** the database connection that invoked the authorizer callback.
2171** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2172** database connections for the meaning of "modify" in this paragraph.
2173**
2174** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
2175** statement might be re-prepared during [sqlite3_step()] due to a
2176** schema change.  Hence, the application should ensure that the
2177** correct authorizer callback remains in place during the [sqlite3_step()].
2178**
2179** ^Note that the authorizer callback is invoked only during
2180** [sqlite3_prepare()] or its variants.  Authorization is not
2181** performed during statement evaluation in [sqlite3_step()], unless
2182** as stated in the previous paragraph, sqlite3_step() invokes
2183** sqlite3_prepare_v2() to reprepare a statement after a schema change.
2184*/
2185int sqlite3_set_authorizer(
2186  sqlite3*,
2187  int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
2188  void *pUserData
2189);
2190
2191/*
2192** CAPI3REF: Authorizer Return Codes
2193**
2194** The [sqlite3_set_authorizer | authorizer callback function] must
2195** return either [SQLITE_OK] or one of these two constants in order
2196** to signal SQLite whether or not the action is permitted.  See the
2197** [sqlite3_set_authorizer | authorizer documentation] for additional
2198** information.
2199*/
2200#define SQLITE_DENY   1   /* Abort the SQL statement with an error */
2201#define SQLITE_IGNORE 2   /* Don't allow access, but don't generate an error */
2202
2203/*
2204** CAPI3REF: Authorizer Action Codes
2205**
2206** The [sqlite3_set_authorizer()] interface registers a callback function
2207** that is invoked to authorize certain SQL statement actions.  The
2208** second parameter to the callback is an integer code that specifies
2209** what action is being authorized.  These are the integer action codes that
2210** the authorizer callback may be passed.
2211**
2212** These action code values signify what kind of operation is to be
2213** authorized.  The 3rd and 4th parameters to the authorization
2214** callback function will be parameters or NULL depending on which of these
2215** codes is used as the second parameter.  ^(The 5th parameter to the
2216** authorizer callback is the name of the database ("main", "temp",
2217** etc.) if applicable.)^  ^The 6th parameter to the authorizer callback
2218** is the name of the inner-most trigger or view that is responsible for
2219** the access attempt or NULL if this access attempt is directly from
2220** top-level SQL code.
2221*/
2222/******************************************* 3rd ************ 4th ***********/
2223#define SQLITE_CREATE_INDEX          1   /* Index Name      Table Name      */
2224#define SQLITE_CREATE_TABLE          2   /* Table Name      NULL            */
2225#define SQLITE_CREATE_TEMP_INDEX     3   /* Index Name      Table Name      */
2226#define SQLITE_CREATE_TEMP_TABLE     4   /* Table Name      NULL            */
2227#define SQLITE_CREATE_TEMP_TRIGGER   5   /* Trigger Name    Table Name      */
2228#define SQLITE_CREATE_TEMP_VIEW      6   /* View Name       NULL            */
2229#define SQLITE_CREATE_TRIGGER        7   /* Trigger Name    Table Name      */
2230#define SQLITE_CREATE_VIEW           8   /* View Name       NULL            */
2231#define SQLITE_DELETE                9   /* Table Name      NULL            */
2232#define SQLITE_DROP_INDEX           10   /* Index Name      Table Name      */
2233#define SQLITE_DROP_TABLE           11   /* Table Name      NULL            */
2234#define SQLITE_DROP_TEMP_INDEX      12   /* Index Name      Table Name      */
2235#define SQLITE_DROP_TEMP_TABLE      13   /* Table Name      NULL            */
2236#define SQLITE_DROP_TEMP_TRIGGER    14   /* Trigger Name    Table Name      */
2237#define SQLITE_DROP_TEMP_VIEW       15   /* View Name       NULL            */
2238#define SQLITE_DROP_TRIGGER         16   /* Trigger Name    Table Name      */
2239#define SQLITE_DROP_VIEW            17   /* View Name       NULL            */
2240#define SQLITE_INSERT               18   /* Table Name      NULL            */
2241#define SQLITE_PRAGMA               19   /* Pragma Name     1st arg or NULL */
2242#define SQLITE_READ                 20   /* Table Name      Column Name     */
2243#define SQLITE_SELECT               21   /* NULL            NULL            */
2244#define SQLITE_TRANSACTION          22   /* Operation       NULL            */
2245#define SQLITE_UPDATE               23   /* Table Name      Column Name     */
2246#define SQLITE_ATTACH               24   /* Filename        NULL            */
2247#define SQLITE_DETACH               25   /* Database Name   NULL            */
2248#define SQLITE_ALTER_TABLE          26   /* Database Name   Table Name      */
2249#define SQLITE_REINDEX              27   /* Index Name      NULL            */
2250#define SQLITE_ANALYZE              28   /* Table Name      NULL            */
2251#define SQLITE_CREATE_VTABLE        29   /* Table Name      Module Name     */
2252#define SQLITE_DROP_VTABLE          30   /* Table Name      Module Name     */
2253#define SQLITE_FUNCTION             31   /* NULL            Function Name   */
2254#define SQLITE_SAVEPOINT            32   /* Operation       Savepoint Name  */
2255#define SQLITE_COPY                  0   /* No longer used */
2256
2257/*
2258** CAPI3REF: Tracing And Profiling Functions
2259**
2260** These routines register callback functions that can be used for
2261** tracing and profiling the execution of SQL statements.
2262**
2263** ^The callback function registered by sqlite3_trace() is invoked at
2264** various times when an SQL statement is being run by [sqlite3_step()].
2265** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
2266** SQL statement text as the statement first begins executing.
2267** ^(Additional sqlite3_trace() callbacks might occur
2268** as each triggered subprogram is entered.  The callbacks for triggers
2269** contain a UTF-8 SQL comment that identifies the trigger.)^
2270**
2271** ^The callback function registered by sqlite3_profile() is invoked
2272** as each SQL statement finishes.  ^The profile callback contains
2273** the original statement text and an estimate of wall-clock time
2274** of how long that statement took to run.  ^The profile callback
2275** time is in units of nanoseconds, however the current implementation
2276** is only capable of millisecond resolution so the six least significant
2277** digits in the time are meaningless.  Future versions of SQLite
2278** might provide greater resolution on the profiler callback.  The
2279** sqlite3_profile() function is considered experimental and is
2280** subject to change in future versions of SQLite.
2281*/
2282void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*);
2283SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*,
2284   void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
2285
2286/*
2287** CAPI3REF: Query Progress Callbacks
2288**
2289** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
2290** function X to be invoked periodically during long running calls to
2291** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for
2292** database connection D.  An example use for this
2293** interface is to keep a GUI updated during a large query.
2294**
2295** ^The parameter P is passed through as the only parameter to the
2296** callback function X.  ^The parameter N is the number of
2297** [virtual machine instructions] that are evaluated between successive
2298** invocations of the callback X.
2299**
2300** ^Only a single progress handler may be defined at one time per
2301** [database connection]; setting a new progress handler cancels the
2302** old one.  ^Setting parameter X to NULL disables the progress handler.
2303** ^The progress handler is also disabled by setting N to a value less
2304** than 1.
2305**
2306** ^If the progress callback returns non-zero, the operation is
2307** interrupted.  This feature can be used to implement a
2308** "Cancel" button on a GUI progress dialog box.
2309**
2310** The progress handler callback must not do anything that will modify
2311** the database connection that invoked the progress handler.
2312** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2313** database connections for the meaning of "modify" in this paragraph.
2314**
2315*/
2316void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
2317
2318/*
2319** CAPI3REF: Opening A New Database Connection
2320**
2321** ^These routines open an SQLite database file whose name is given by the
2322** filename argument. ^The filename argument is interpreted as UTF-8 for
2323** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
2324** order for sqlite3_open16(). ^(A [database connection] handle is usually
2325** returned in *ppDb, even if an error occurs.  The only exception is that
2326** if SQLite is unable to allocate memory to hold the [sqlite3] object,
2327** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
2328** object.)^ ^(If the database is opened (and/or created) successfully, then
2329** [SQLITE_OK] is returned.  Otherwise an [error code] is returned.)^ ^The
2330** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
2331** an English language description of the error following a failure of any
2332** of the sqlite3_open() routines.
2333**
2334** ^The default encoding for the database will be UTF-8 if
2335** sqlite3_open() or sqlite3_open_v2() is called and
2336** UTF-16 in the native byte order if sqlite3_open16() is used.
2337**
2338** Whether or not an error occurs when it is opened, resources
2339** associated with the [database connection] handle should be released by
2340** passing it to [sqlite3_close()] when it is no longer required.
2341**
2342** The sqlite3_open_v2() interface works like sqlite3_open()
2343** except that it accepts two additional parameters for additional control
2344** over the new database connection.  ^(The flags parameter to
2345** sqlite3_open_v2() can take one of
2346** the following three values, optionally combined with the
2347** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE],
2348** and/or [SQLITE_OPEN_PRIVATECACHE] flags:)^
2349**
2350** <dl>
2351** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
2352** <dd>The database is opened in read-only mode.  If the database does not
2353** already exist, an error is returned.</dd>)^
2354**
2355** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
2356** <dd>The database is opened for reading and writing if possible, or reading
2357** only if the file is write protected by the operating system.  In either
2358** case the database must already exist, otherwise an error is returned.</dd>)^
2359**
2360** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
2361** <dd>The database is opened for reading and writing, and is created if
2362** it does not already exist. This is the behavior that is always used for
2363** sqlite3_open() and sqlite3_open16().</dd>)^
2364** </dl>
2365**
2366** If the 3rd parameter to sqlite3_open_v2() is not one of the
2367** combinations shown above or one of the combinations shown above combined
2368** with the [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX],
2369** [SQLITE_OPEN_SHAREDCACHE] and/or [SQLITE_OPEN_PRIVATECACHE] flags,
2370** then the behavior is undefined.
2371**
2372** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection
2373** opens in the multi-thread [threading mode] as long as the single-thread
2374** mode has not been set at compile-time or start-time.  ^If the
2375** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens
2376** in the serialized [threading mode] unless single-thread was
2377** previously selected at compile-time or start-time.
2378** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be
2379** eligible to use [shared cache mode], regardless of whether or not shared
2380** cache is enabled using [sqlite3_enable_shared_cache()].  ^The
2381** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not
2382** participate in [shared cache mode] even if it is enabled.
2383**
2384** ^If the filename is ":memory:", then a private, temporary in-memory database
2385** is created for the connection.  ^This in-memory database will vanish when
2386** the database connection is closed.  Future versions of SQLite might
2387** make use of additional special filenames that begin with the ":" character.
2388** It is recommended that when a database filename actually does begin with
2389** a ":" character you should prefix the filename with a pathname such as
2390** "./" to avoid ambiguity.
2391**
2392** ^If the filename is an empty string, then a private, temporary
2393** on-disk database will be created.  ^This private database will be
2394** automatically deleted as soon as the database connection is closed.
2395**
2396** ^The fourth parameter to sqlite3_open_v2() is the name of the
2397** [sqlite3_vfs] object that defines the operating system interface that
2398** the new database connection should use.  ^If the fourth parameter is
2399** a NULL pointer then the default [sqlite3_vfs] object is used.
2400**
2401** <b>Note to Windows users:</b>  The encoding used for the filename argument
2402** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
2403** codepage is currently defined.  Filenames containing international
2404** characters must be converted to UTF-8 prior to passing them into
2405** sqlite3_open() or sqlite3_open_v2().
2406*/
2407int sqlite3_open(
2408  const char *filename,   /* Database filename (UTF-8) */
2409  sqlite3 **ppDb          /* OUT: SQLite db handle */
2410);
2411int sqlite3_open16(
2412  const void *filename,   /* Database filename (UTF-16) */
2413  sqlite3 **ppDb          /* OUT: SQLite db handle */
2414);
2415int sqlite3_open_v2(
2416  const char *filename,   /* Database filename (UTF-8) */
2417  sqlite3 **ppDb,         /* OUT: SQLite db handle */
2418  int flags,              /* Flags */
2419  const char *zVfs        /* Name of VFS module to use */
2420);
2421
2422/*
2423** CAPI3REF: Error Codes And Messages
2424**
2425** ^The sqlite3_errcode() interface returns the numeric [result code] or
2426** [extended result code] for the most recent failed sqlite3_* API call
2427** associated with a [database connection]. If a prior API call failed
2428** but the most recent API call succeeded, the return value from
2429** sqlite3_errcode() is undefined.  ^The sqlite3_extended_errcode()
2430** interface is the same except that it always returns the
2431** [extended result code] even when extended result codes are
2432** disabled.
2433**
2434** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
2435** text that describes the error, as either UTF-8 or UTF-16 respectively.
2436** ^(Memory to hold the error message string is managed internally.
2437** The application does not need to worry about freeing the result.
2438** However, the error string might be overwritten or deallocated by
2439** subsequent calls to other SQLite interface functions.)^
2440**
2441** When the serialized [threading mode] is in use, it might be the
2442** case that a second error occurs on a separate thread in between
2443** the time of the first error and the call to these interfaces.
2444** When that happens, the second error will be reported since these
2445** interfaces always report the most recent result.  To avoid
2446** this, each thread can obtain exclusive use of the [database connection] D
2447** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
2448** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
2449** all calls to the interfaces listed here are completed.
2450**
2451** If an interface fails with SQLITE_MISUSE, that means the interface
2452** was invoked incorrectly by the application.  In that case, the
2453** error code and message may or may not be set.
2454*/
2455int sqlite3_errcode(sqlite3 *db);
2456int sqlite3_extended_errcode(sqlite3 *db);
2457const char *sqlite3_errmsg(sqlite3*);
2458const void *sqlite3_errmsg16(sqlite3*);
2459
2460/*
2461** CAPI3REF: SQL Statement Object
2462** KEYWORDS: {prepared statement} {prepared statements}
2463**
2464** An instance of this object represents a single SQL statement.
2465** This object is variously known as a "prepared statement" or a
2466** "compiled SQL statement" or simply as a "statement".
2467**
2468** The life of a statement object goes something like this:
2469**
2470** <ol>
2471** <li> Create the object using [sqlite3_prepare_v2()] or a related
2472**      function.
2473** <li> Bind values to [host parameters] using the sqlite3_bind_*()
2474**      interfaces.
2475** <li> Run the SQL by calling [sqlite3_step()] one or more times.
2476** <li> Reset the statement using [sqlite3_reset()] then go back
2477**      to step 2.  Do this zero or more times.
2478** <li> Destroy the object using [sqlite3_finalize()].
2479** </ol>
2480**
2481** Refer to documentation on individual methods above for additional
2482** information.
2483*/
2484typedef struct sqlite3_stmt sqlite3_stmt;
2485
2486/*
2487** CAPI3REF: Run-time Limits
2488**
2489** ^(This interface allows the size of various constructs to be limited
2490** on a connection by connection basis.  The first parameter is the
2491** [database connection] whose limit is to be set or queried.  The
2492** second parameter is one of the [limit categories] that define a
2493** class of constructs to be size limited.  The third parameter is the
2494** new limit for that construct.)^
2495**
2496** ^If the new limit is a negative number, the limit is unchanged.
2497** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
2498** [limits | hard upper bound]
2499** set at compile-time by a C preprocessor macro called
2500** [limits | SQLITE_MAX_<i>NAME</i>].
2501** (The "_LIMIT_" in the name is changed to "_MAX_".))^
2502** ^Attempts to increase a limit above its hard upper bound are
2503** silently truncated to the hard upper bound.
2504**
2505** ^Regardless of whether or not the limit was changed, the
2506** [sqlite3_limit()] interface returns the prior value of the limit.
2507** ^Hence, to find the current value of a limit without changing it,
2508** simply invoke this interface with the third parameter set to -1.
2509**
2510** Run-time limits are intended for use in applications that manage
2511** both their own internal database and also databases that are controlled
2512** by untrusted external sources.  An example application might be a
2513** web browser that has its own databases for storing history and
2514** separate databases controlled by JavaScript applications downloaded
2515** off the Internet.  The internal databases can be given the
2516** large, default limits.  Databases managed by external sources can
2517** be given much smaller limits designed to prevent a denial of service
2518** attack.  Developers might also want to use the [sqlite3_set_authorizer()]
2519** interface to further control untrusted SQL.  The size of the database
2520** created by an untrusted script can be contained using the
2521** [max_page_count] [PRAGMA].
2522**
2523** New run-time limit categories may be added in future releases.
2524*/
2525int sqlite3_limit(sqlite3*, int id, int newVal);
2526
2527/*
2528** CAPI3REF: Run-Time Limit Categories
2529** KEYWORDS: {limit category} {*limit categories}
2530**
2531** These constants define various performance limits
2532** that can be lowered at run-time using [sqlite3_limit()].
2533** The synopsis of the meanings of the various limits is shown below.
2534** Additional information is available at [limits | Limits in SQLite].
2535**
2536** <dl>
2537** ^(<dt>SQLITE_LIMIT_LENGTH</dt>
2538** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
2539**
2540** ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
2541** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
2542**
2543** ^(<dt>SQLITE_LIMIT_COLUMN</dt>
2544** <dd>The maximum number of columns in a table definition or in the
2545** result set of a [SELECT] or the maximum number of columns in an index
2546** or in an ORDER BY or GROUP BY clause.</dd>)^
2547**
2548** ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
2549** <dd>The maximum depth of the parse tree on any expression.</dd>)^
2550**
2551** ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
2552** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
2553**
2554** ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
2555** <dd>The maximum number of instructions in a virtual machine program
2556** used to implement an SQL statement.  This limit is not currently
2557** enforced, though that might be added in some future release of
2558** SQLite.</dd>)^
2559**
2560** ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
2561** <dd>The maximum number of arguments on a function.</dd>)^
2562**
2563** ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
2564** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
2565**
2566** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
2567** <dd>The maximum length of the pattern argument to the [LIKE] or
2568** [GLOB] operators.</dd>)^
2569**
2570** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
2571** <dd>The maximum index number of any [parameter] in an SQL statement.)^
2572**
2573** ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
2574** <dd>The maximum depth of recursion for triggers.</dd>)^
2575** </dl>
2576*/
2577#define SQLITE_LIMIT_LENGTH                    0
2578#define SQLITE_LIMIT_SQL_LENGTH                1
2579#define SQLITE_LIMIT_COLUMN                    2
2580#define SQLITE_LIMIT_EXPR_DEPTH                3
2581#define SQLITE_LIMIT_COMPOUND_SELECT           4
2582#define SQLITE_LIMIT_VDBE_OP                   5
2583#define SQLITE_LIMIT_FUNCTION_ARG              6
2584#define SQLITE_LIMIT_ATTACHED                  7
2585#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH       8
2586#define SQLITE_LIMIT_VARIABLE_NUMBER           9
2587#define SQLITE_LIMIT_TRIGGER_DEPTH            10
2588
2589/*
2590** CAPI3REF: Compiling An SQL Statement
2591** KEYWORDS: {SQL statement compiler}
2592**
2593** To execute an SQL query, it must first be compiled into a byte-code
2594** program using one of these routines.
2595**
2596** The first argument, "db", is a [database connection] obtained from a
2597** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
2598** [sqlite3_open16()].  The database connection must not have been closed.
2599**
2600** The second argument, "zSql", is the statement to be compiled, encoded
2601** as either UTF-8 or UTF-16.  The sqlite3_prepare() and sqlite3_prepare_v2()
2602** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2()
2603** use UTF-16.
2604**
2605** ^If the nByte argument is less than zero, then zSql is read up to the
2606** first zero terminator. ^If nByte is non-negative, then it is the maximum
2607** number of  bytes read from zSql.  ^When nByte is non-negative, the
2608** zSql string ends at either the first '\000' or '\u0000' character or
2609** the nByte-th byte, whichever comes first. If the caller knows
2610** that the supplied string is nul-terminated, then there is a small
2611** performance advantage to be gained by passing an nByte parameter that
2612** is equal to the number of bytes in the input string <i>including</i>
2613** the nul-terminator bytes.
2614**
2615** ^If pzTail is not NULL then *pzTail is made to point to the first byte
2616** past the end of the first SQL statement in zSql.  These routines only
2617** compile the first statement in zSql, so *pzTail is left pointing to
2618** what remains uncompiled.
2619**
2620** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
2621** executed using [sqlite3_step()].  ^If there is an error, *ppStmt is set
2622** to NULL.  ^If the input text contains no SQL (if the input is an empty
2623** string or a comment) then *ppStmt is set to NULL.
2624** The calling procedure is responsible for deleting the compiled
2625** SQL statement using [sqlite3_finalize()] after it has finished with it.
2626** ppStmt may not be NULL.
2627**
2628** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
2629** otherwise an [error code] is returned.
2630**
2631** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are
2632** recommended for all new programs. The two older interfaces are retained
2633** for backwards compatibility, but their use is discouraged.
2634** ^In the "v2" interfaces, the prepared statement
2635** that is returned (the [sqlite3_stmt] object) contains a copy of the
2636** original SQL text. This causes the [sqlite3_step()] interface to
2637** behave differently in three ways:
2638**
2639** <ol>
2640** <li>
2641** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
2642** always used to do, [sqlite3_step()] will automatically recompile the SQL
2643** statement and try to run it again.
2644** </li>
2645**
2646** <li>
2647** ^When an error occurs, [sqlite3_step()] will return one of the detailed
2648** [error codes] or [extended error codes].  ^The legacy behavior was that
2649** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
2650** and the application would have to make a second call to [sqlite3_reset()]
2651** in order to find the underlying cause of the problem. With the "v2" prepare
2652** interfaces, the underlying reason for the error is returned immediately.
2653** </li>
2654**
2655** <li>
2656** ^If the specific value bound to [parameter | host parameter] in the
2657** WHERE clause might influence the choice of query plan for a statement,
2658** then the statement will be automatically recompiled, as if there had been
2659** a schema change, on the first  [sqlite3_step()] call following any change
2660** to the [sqlite3_bind_text | bindings] of that [parameter].
2661** ^The specific value of WHERE-clause [parameter] might influence the
2662** choice of query plan if the parameter is the left-hand side of a [LIKE]
2663** or [GLOB] operator or if the parameter is compared to an indexed column
2664** and the [SQLITE_ENABLE_STAT2] compile-time option is enabled.
2665** the
2666** </li>
2667** </ol>
2668*/
2669int sqlite3_prepare(
2670  sqlite3 *db,            /* Database handle */
2671  const char *zSql,       /* SQL statement, UTF-8 encoded */
2672  int nByte,              /* Maximum length of zSql in bytes. */
2673  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
2674  const char **pzTail     /* OUT: Pointer to unused portion of zSql */
2675);
2676int sqlite3_prepare_v2(
2677  sqlite3 *db,            /* Database handle */
2678  const char *zSql,       /* SQL statement, UTF-8 encoded */
2679  int nByte,              /* Maximum length of zSql in bytes. */
2680  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
2681  const char **pzTail     /* OUT: Pointer to unused portion of zSql */
2682);
2683int sqlite3_prepare16(
2684  sqlite3 *db,            /* Database handle */
2685  const void *zSql,       /* SQL statement, UTF-16 encoded */
2686  int nByte,              /* Maximum length of zSql in bytes. */
2687  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
2688  const void **pzTail     /* OUT: Pointer to unused portion of zSql */
2689);
2690int sqlite3_prepare16_v2(
2691  sqlite3 *db,            /* Database handle */
2692  const void *zSql,       /* SQL statement, UTF-16 encoded */
2693  int nByte,              /* Maximum length of zSql in bytes. */
2694  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
2695  const void **pzTail     /* OUT: Pointer to unused portion of zSql */
2696);
2697
2698/*
2699** CAPI3REF: Retrieving Statement SQL
2700**
2701** ^This interface can be used to retrieve a saved copy of the original
2702** SQL text used to create a [prepared statement] if that statement was
2703** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()].
2704*/
2705const char *sqlite3_sql(sqlite3_stmt *pStmt);
2706
2707/*
2708** CAPI3REF: Determine If An SQL Statement Writes The Database
2709**
2710** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
2711** and only if the [prepared statement] X makes no direct changes to
2712** the content of the database file.
2713**
2714** Note that [application-defined SQL functions] or
2715** [virtual tables] might change the database indirectly as a side effect.
2716** ^(For example, if an application defines a function "eval()" that
2717** calls [sqlite3_exec()], then the following SQL statement would
2718** change the database file through side-effects:
2719**
2720** <blockquote><pre>
2721**    SELECT eval('DELETE FROM t1') FROM t2;
2722** </pre></blockquote>
2723**
2724** But because the [SELECT] statement does not change the database file
2725** directly, sqlite3_stmt_readonly() would still return true.)^
2726**
2727** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
2728** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
2729** since the statements themselves do not actually modify the database but
2730** rather they control the timing of when other statements modify the
2731** database.  ^The [ATTACH] and [DETACH] statements also cause
2732** sqlite3_stmt_readonly() to return true since, while those statements
2733** change the configuration of a database connection, they do not make
2734** changes to the content of the database files on disk.
2735*/
2736int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
2737
2738/*
2739** CAPI3REF: Dynamically Typed Value Object
2740** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
2741**
2742** SQLite uses the sqlite3_value object to represent all values
2743** that can be stored in a database table. SQLite uses dynamic typing
2744** for the values it stores.  ^Values stored in sqlite3_value objects
2745** can be integers, floating point values, strings, BLOBs, or NULL.
2746**
2747** An sqlite3_value object may be either "protected" or "unprotected".
2748** Some interfaces require a protected sqlite3_value.  Other interfaces
2749** will accept either a protected or an unprotected sqlite3_value.
2750** Every interface that accepts sqlite3_value arguments specifies
2751** whether or not it requires a protected sqlite3_value.
2752**
2753** The terms "protected" and "unprotected" refer to whether or not
2754** a mutex is held.  An internal mutex is held for a protected
2755** sqlite3_value object but no mutex is held for an unprotected
2756** sqlite3_value object.  If SQLite is compiled to be single-threaded
2757** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
2758** or if SQLite is run in one of reduced mutex modes
2759** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
2760** then there is no distinction between protected and unprotected
2761** sqlite3_value objects and they can be used interchangeably.  However,
2762** for maximum code portability it is recommended that applications
2763** still make the distinction between protected and unprotected
2764** sqlite3_value objects even when not strictly required.
2765**
2766** ^The sqlite3_value objects that are passed as parameters into the
2767** implementation of [application-defined SQL functions] are protected.
2768** ^The sqlite3_value object returned by
2769** [sqlite3_column_value()] is unprotected.
2770** Unprotected sqlite3_value objects may only be used with
2771** [sqlite3_result_value()] and [sqlite3_bind_value()].
2772** The [sqlite3_value_blob | sqlite3_value_type()] family of
2773** interfaces require protected sqlite3_value objects.
2774*/
2775typedef struct Mem sqlite3_value;
2776
2777/*
2778** CAPI3REF: SQL Function Context Object
2779**
2780** The context in which an SQL function executes is stored in an
2781** sqlite3_context object.  ^A pointer to an sqlite3_context object
2782** is always first parameter to [application-defined SQL functions].
2783** The application-defined SQL function implementation will pass this
2784** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
2785** [sqlite3_aggregate_context()], [sqlite3_user_data()],
2786** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
2787** and/or [sqlite3_set_auxdata()].
2788*/
2789typedef struct sqlite3_context sqlite3_context;
2790
2791/*
2792** CAPI3REF: Binding Values To Prepared Statements
2793** KEYWORDS: {host parameter} {host parameters} {host parameter name}
2794** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
2795**
2796** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
2797** literals may be replaced by a [parameter] that matches one of following
2798** templates:
2799**
2800** <ul>
2801** <li>  ?
2802** <li>  ?NNN
2803** <li>  :VVV
2804** <li>  @VVV
2805** <li>  $VVV
2806** </ul>
2807**
2808** In the templates above, NNN represents an integer literal,
2809** and VVV represents an alphanumeric identifier.)^  ^The values of these
2810** parameters (also called "host parameter names" or "SQL parameters")
2811** can be set using the sqlite3_bind_*() routines defined here.
2812**
2813** ^The first argument to the sqlite3_bind_*() routines is always
2814** a pointer to the [sqlite3_stmt] object returned from
2815** [sqlite3_prepare_v2()] or its variants.
2816**
2817** ^The second argument is the index of the SQL parameter to be set.
2818** ^The leftmost SQL parameter has an index of 1.  ^When the same named
2819** SQL parameter is used more than once, second and subsequent
2820** occurrences have the same index as the first occurrence.
2821** ^The index for named parameters can be looked up using the
2822** [sqlite3_bind_parameter_index()] API if desired.  ^The index
2823** for "?NNN" parameters is the value of NNN.
2824** ^The NNN value must be between 1 and the [sqlite3_limit()]
2825** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999).
2826**
2827** ^The third argument is the value to bind to the parameter.
2828**
2829** ^(In those routines that have a fourth argument, its value is the
2830** number of bytes in the parameter.  To be clear: the value is the
2831** number of <u>bytes</u> in the value, not the number of characters.)^
2832** ^If the fourth parameter is negative, the length of the string is
2833** the number of bytes up to the first zero terminator.
2834**
2835** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and
2836** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or
2837** string after SQLite has finished with it.  ^The destructor is called
2838** to dispose of the BLOB or string even if the call to sqlite3_bind_blob(),
2839** sqlite3_bind_text(), or sqlite3_bind_text16() fails.
2840** ^If the fifth argument is
2841** the special value [SQLITE_STATIC], then SQLite assumes that the
2842** information is in static, unmanaged space and does not need to be freed.
2843** ^If the fifth argument has the value [SQLITE_TRANSIENT], then
2844** SQLite makes its own private copy of the data immediately, before
2845** the sqlite3_bind_*() routine returns.
2846**
2847** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
2848** is filled with zeroes.  ^A zeroblob uses a fixed amount of memory
2849** (just an integer to hold its size) while it is being processed.
2850** Zeroblobs are intended to serve as placeholders for BLOBs whose
2851** content is later written using
2852** [sqlite3_blob_open | incremental BLOB I/O] routines.
2853** ^A negative value for the zeroblob results in a zero-length BLOB.
2854**
2855** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
2856** for the [prepared statement] or with a prepared statement for which
2857** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
2858** then the call will return [SQLITE_MISUSE].  If any sqlite3_bind_()
2859** routine is passed a [prepared statement] that has been finalized, the
2860** result is undefined and probably harmful.
2861**
2862** ^Bindings are not cleared by the [sqlite3_reset()] routine.
2863** ^Unbound parameters are interpreted as NULL.
2864**
2865** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
2866** [error code] if anything goes wrong.
2867** ^[SQLITE_RANGE] is returned if the parameter
2868** index is out of range.  ^[SQLITE_NOMEM] is returned if malloc() fails.
2869**
2870** See also: [sqlite3_bind_parameter_count()],
2871** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
2872*/
2873int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
2874int sqlite3_bind_double(sqlite3_stmt*, int, double);
2875int sqlite3_bind_int(sqlite3_stmt*, int, int);
2876int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
2877int sqlite3_bind_null(sqlite3_stmt*, int);
2878int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*));
2879int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
2880int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
2881int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
2882
2883/*
2884** CAPI3REF: Number Of SQL Parameters
2885**
2886** ^This routine can be used to find the number of [SQL parameters]
2887** in a [prepared statement].  SQL parameters are tokens of the
2888** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
2889** placeholders for values that are [sqlite3_bind_blob | bound]
2890** to the parameters at a later time.
2891**
2892** ^(This routine actually returns the index of the largest (rightmost)
2893** parameter. For all forms except ?NNN, this will correspond to the
2894** number of unique parameters.  If parameters of the ?NNN form are used,
2895** there may be gaps in the list.)^
2896**
2897** See also: [sqlite3_bind_blob|sqlite3_bind()],
2898** [sqlite3_bind_parameter_name()], and
2899** [sqlite3_bind_parameter_index()].
2900*/
2901int sqlite3_bind_parameter_count(sqlite3_stmt*);
2902
2903/*
2904** CAPI3REF: Name Of A Host Parameter
2905**
2906** ^The sqlite3_bind_parameter_name(P,N) interface returns
2907** the name of the N-th [SQL parameter] in the [prepared statement] P.
2908** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
2909** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
2910** respectively.
2911** In other words, the initial ":" or "$" or "@" or "?"
2912** is included as part of the name.)^
2913** ^Parameters of the form "?" without a following integer have no name
2914** and are referred to as "nameless" or "anonymous parameters".
2915**
2916** ^The first host parameter has an index of 1, not 0.
2917**
2918** ^If the value N is out of range or if the N-th parameter is
2919** nameless, then NULL is returned.  ^The returned string is
2920** always in UTF-8 encoding even if the named parameter was
2921** originally specified as UTF-16 in [sqlite3_prepare16()] or
2922** [sqlite3_prepare16_v2()].
2923**
2924** See also: [sqlite3_bind_blob|sqlite3_bind()],
2925** [sqlite3_bind_parameter_count()], and
2926** [sqlite3_bind_parameter_index()].
2927*/
2928const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
2929
2930/*
2931** CAPI3REF: Index Of A Parameter With A Given Name
2932**
2933** ^Return the index of an SQL parameter given its name.  ^The
2934** index value returned is suitable for use as the second
2935** parameter to [sqlite3_bind_blob|sqlite3_bind()].  ^A zero
2936** is returned if no matching parameter is found.  ^The parameter
2937** name must be given in UTF-8 even if the original statement
2938** was prepared from UTF-16 text using [sqlite3_prepare16_v2()].
2939**
2940** See also: [sqlite3_bind_blob|sqlite3_bind()],
2941** [sqlite3_bind_parameter_count()], and
2942** [sqlite3_bind_parameter_index()].
2943*/
2944int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
2945
2946/*
2947** CAPI3REF: Reset All Bindings On A Prepared Statement
2948**
2949** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
2950** the [sqlite3_bind_blob | bindings] on a [prepared statement].
2951** ^Use this routine to reset all host parameters to NULL.
2952*/
2953int sqlite3_clear_bindings(sqlite3_stmt*);
2954
2955/*
2956** CAPI3REF: Number Of Columns In A Result Set
2957**
2958** ^Return the number of columns in the result set returned by the
2959** [prepared statement]. ^This routine returns 0 if pStmt is an SQL
2960** statement that does not return data (for example an [UPDATE]).
2961**
2962** See also: [sqlite3_data_count()]
2963*/
2964int sqlite3_column_count(sqlite3_stmt *pStmt);
2965
2966/*
2967** CAPI3REF: Column Names In A Result Set
2968**
2969** ^These routines return the name assigned to a particular column
2970** in the result set of a [SELECT] statement.  ^The sqlite3_column_name()
2971** interface returns a pointer to a zero-terminated UTF-8 string
2972** and sqlite3_column_name16() returns a pointer to a zero-terminated
2973** UTF-16 string.  ^The first parameter is the [prepared statement]
2974** that implements the [SELECT] statement. ^The second parameter is the
2975** column number.  ^The leftmost column is number 0.
2976**
2977** ^The returned string pointer is valid until either the [prepared statement]
2978** is destroyed by [sqlite3_finalize()] or until the statement is automatically
2979** reprepared by the first call to [sqlite3_step()] for a particular run
2980** or until the next call to
2981** sqlite3_column_name() or sqlite3_column_name16() on the same column.
2982**
2983** ^If sqlite3_malloc() fails during the processing of either routine
2984** (for example during a conversion from UTF-8 to UTF-16) then a
2985** NULL pointer is returned.
2986**
2987** ^The name of a result column is the value of the "AS" clause for
2988** that column, if there is an AS clause.  If there is no AS clause
2989** then the name of the column is unspecified and may change from
2990** one release of SQLite to the next.
2991*/
2992const char *sqlite3_column_name(sqlite3_stmt*, int N);
2993const void *sqlite3_column_name16(sqlite3_stmt*, int N);
2994
2995/*
2996** CAPI3REF: Source Of Data In A Query Result
2997**
2998** ^These routines provide a means to determine the database, table, and
2999** table column that is the origin of a particular result column in
3000** [SELECT] statement.
3001** ^The name of the database or table or column can be returned as
3002** either a UTF-8 or UTF-16 string.  ^The _database_ routines return
3003** the database name, the _table_ routines return the table name, and
3004** the origin_ routines return the column name.
3005** ^The returned string is valid until the [prepared statement] is destroyed
3006** using [sqlite3_finalize()] or until the statement is automatically
3007** reprepared by the first call to [sqlite3_step()] for a particular run
3008** or until the same information is requested
3009** again in a different encoding.
3010**
3011** ^The names returned are the original un-aliased names of the
3012** database, table, and column.
3013**
3014** ^The first argument to these interfaces is a [prepared statement].
3015** ^These functions return information about the Nth result column returned by
3016** the statement, where N is the second function argument.
3017** ^The left-most column is column 0 for these routines.
3018**
3019** ^If the Nth column returned by the statement is an expression or
3020** subquery and is not a column value, then all of these functions return
3021** NULL.  ^These routine might also return NULL if a memory allocation error
3022** occurs.  ^Otherwise, they return the name of the attached database, table,
3023** or column that query result column was extracted from.
3024**
3025** ^As with all other SQLite APIs, those whose names end with "16" return
3026** UTF-16 encoded strings and the other functions return UTF-8.
3027**
3028** ^These APIs are only available if the library was compiled with the
3029** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
3030**
3031** If two or more threads call one or more of these routines against the same
3032** prepared statement and column at the same time then the results are
3033** undefined.
3034**
3035** If two or more threads call one or more
3036** [sqlite3_column_database_name | column metadata interfaces]
3037** for the same [prepared statement] and result column
3038** at the same time then the results are undefined.
3039*/
3040const char *sqlite3_column_database_name(sqlite3_stmt*,int);
3041const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
3042const char *sqlite3_column_table_name(sqlite3_stmt*,int);
3043const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
3044const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
3045const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
3046
3047/*
3048** CAPI3REF: Declared Datatype Of A Query Result
3049**
3050** ^(The first parameter is a [prepared statement].
3051** If this statement is a [SELECT] statement and the Nth column of the
3052** returned result set of that [SELECT] is a table column (not an
3053** expression or subquery) then the declared type of the table
3054** column is returned.)^  ^If the Nth column of the result set is an
3055** expression or subquery, then a NULL pointer is returned.
3056** ^The returned string is always UTF-8 encoded.
3057**
3058** ^(For example, given the database schema:
3059**
3060** CREATE TABLE t1(c1 VARIANT);
3061**
3062** and the following statement to be compiled:
3063**
3064** SELECT c1 + 1, c1 FROM t1;
3065**
3066** this routine would return the string "VARIANT" for the second result
3067** column (i==1), and a NULL pointer for the first result column (i==0).)^
3068**
3069** ^SQLite uses dynamic run-time typing.  ^So just because a column
3070** is declared to contain a particular type does not mean that the
3071** data stored in that column is of the declared type.  SQLite is
3072** strongly typed, but the typing is dynamic not static.  ^Type
3073** is associated with individual values, not with the containers
3074** used to hold those values.
3075*/
3076const char *sqlite3_column_decltype(sqlite3_stmt*,int);
3077const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
3078
3079/*
3080** CAPI3REF: Evaluate An SQL Statement
3081**
3082** After a [prepared statement] has been prepared using either
3083** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy
3084** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
3085** must be called one or more times to evaluate the statement.
3086**
3087** The details of the behavior of the sqlite3_step() interface depend
3088** on whether the statement was prepared using the newer "v2" interface
3089** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy
3090** interface [sqlite3_prepare()] and [sqlite3_prepare16()].  The use of the
3091** new "v2" interface is recommended for new applications but the legacy
3092** interface will continue to be supported.
3093**
3094** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
3095** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
3096** ^With the "v2" interface, any of the other [result codes] or
3097** [extended result codes] might be returned as well.
3098**
3099** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
3100** database locks it needs to do its job.  ^If the statement is a [COMMIT]
3101** or occurs outside of an explicit transaction, then you can retry the
3102** statement.  If the statement is not a [COMMIT] and occurs within a
3103** explicit transaction then you should rollback the transaction before
3104** continuing.
3105**
3106** ^[SQLITE_DONE] means that the statement has finished executing
3107** successfully.  sqlite3_step() should not be called again on this virtual
3108** machine without first calling [sqlite3_reset()] to reset the virtual
3109** machine back to its initial state.
3110**
3111** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
3112** is returned each time a new row of data is ready for processing by the
3113** caller. The values may be accessed using the [column access functions].
3114** sqlite3_step() is called again to retrieve the next row of data.
3115**
3116** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
3117** violation) has occurred.  sqlite3_step() should not be called again on
3118** the VM. More information may be found by calling [sqlite3_errmsg()].
3119** ^With the legacy interface, a more specific error code (for example,
3120** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
3121** can be obtained by calling [sqlite3_reset()] on the
3122** [prepared statement].  ^In the "v2" interface,
3123** the more specific error code is returned directly by sqlite3_step().
3124**
3125** [SQLITE_MISUSE] means that the this routine was called inappropriately.
3126** Perhaps it was called on a [prepared statement] that has
3127** already been [sqlite3_finalize | finalized] or on one that had
3128** previously returned [SQLITE_ERROR] or [SQLITE_DONE].  Or it could
3129** be the case that the same database connection is being used by two or
3130** more threads at the same moment in time.
3131**
3132** For all versions of SQLite up to and including 3.6.23.1, a call to
3133** [sqlite3_reset()] was required after sqlite3_step() returned anything
3134** other than [SQLITE_ROW] before any subsequent invocation of
3135** sqlite3_step().  Failure to reset the prepared statement using
3136** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
3137** sqlite3_step().  But after version 3.6.23.1, sqlite3_step() began
3138** calling [sqlite3_reset()] automatically in this circumstance rather
3139** than returning [SQLITE_MISUSE].  This is not considered a compatibility
3140** break because any application that ever receives an SQLITE_MISUSE error
3141** is broken by definition.  The [SQLITE_OMIT_AUTORESET] compile-time option
3142** can be used to restore the legacy behavior.
3143**
3144** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
3145** API always returns a generic error code, [SQLITE_ERROR], following any
3146** error other than [SQLITE_BUSY] and [SQLITE_MISUSE].  You must call
3147** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
3148** specific [error codes] that better describes the error.
3149** We admit that this is a goofy design.  The problem has been fixed
3150** with the "v2" interface.  If you prepare all of your SQL statements
3151** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead
3152** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
3153** then the more specific [error codes] are returned directly
3154** by sqlite3_step().  The use of the "v2" interface is recommended.
3155*/
3156int sqlite3_step(sqlite3_stmt*);
3157
3158/*
3159** CAPI3REF: Number of columns in a result set
3160**
3161** ^The sqlite3_data_count(P) interface returns the number of columns in the
3162** current row of the result set of [prepared statement] P.
3163** ^If prepared statement P does not have results ready to return
3164** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of
3165** interfaces) then sqlite3_data_count(P) returns 0.
3166** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
3167**
3168** See also: [sqlite3_column_count()]
3169*/
3170int sqlite3_data_count(sqlite3_stmt *pStmt);
3171
3172/*
3173** CAPI3REF: Fundamental Datatypes
3174** KEYWORDS: SQLITE_TEXT
3175**
3176** ^(Every value in SQLite has one of five fundamental datatypes:
3177**
3178** <ul>
3179** <li> 64-bit signed integer
3180** <li> 64-bit IEEE floating point number
3181** <li> string
3182** <li> BLOB
3183** <li> NULL
3184** </ul>)^
3185**
3186** These constants are codes for each of those types.
3187**
3188** Note that the SQLITE_TEXT constant was also used in SQLite version 2
3189** for a completely different meaning.  Software that links against both
3190** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
3191** SQLITE_TEXT.
3192*/
3193#define SQLITE_INTEGER  1
3194#define SQLITE_FLOAT    2
3195#define SQLITE_BLOB     4
3196#define SQLITE_NULL     5
3197#ifdef SQLITE_TEXT
3198# undef SQLITE_TEXT
3199#else
3200# define SQLITE_TEXT     3
3201#endif
3202#define SQLITE3_TEXT     3
3203
3204/*
3205** CAPI3REF: Result Values From A Query
3206** KEYWORDS: {column access functions}
3207**
3208** These routines form the "result set" interface.
3209**
3210** ^These routines return information about a single column of the current
3211** result row of a query.  ^In every case the first argument is a pointer
3212** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
3213** that was returned from [sqlite3_prepare_v2()] or one of its variants)
3214** and the second argument is the index of the column for which information
3215** should be returned. ^The leftmost column of the result set has the index 0.
3216** ^The number of columns in the result can be determined using
3217** [sqlite3_column_count()].
3218**
3219** If the SQL statement does not currently point to a valid row, or if the
3220** column index is out of range, the result is undefined.
3221** These routines may only be called when the most recent call to
3222** [sqlite3_step()] has returned [SQLITE_ROW] and neither
3223** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
3224** If any of these routines are called after [sqlite3_reset()] or
3225** [sqlite3_finalize()] or after [sqlite3_step()] has returned
3226** something other than [SQLITE_ROW], the results are undefined.
3227** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
3228** are called from a different thread while any of these routines
3229** are pending, then the results are undefined.
3230**
3231** ^The sqlite3_column_type() routine returns the
3232** [SQLITE_INTEGER | datatype code] for the initial data type
3233** of the result column.  ^The returned value is one of [SQLITE_INTEGER],
3234** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].  The value
3235** returned by sqlite3_column_type() is only meaningful if no type
3236** conversions have occurred as described below.  After a type conversion,
3237** the value returned by sqlite3_column_type() is undefined.  Future
3238** versions of SQLite may change the behavior of sqlite3_column_type()
3239** following a type conversion.
3240**
3241** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
3242** routine returns the number of bytes in that BLOB or string.
3243** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
3244** the string to UTF-8 and then returns the number of bytes.
3245** ^If the result is a numeric value then sqlite3_column_bytes() uses
3246** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
3247** the number of bytes in that string.
3248** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
3249**
3250** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
3251** routine returns the number of bytes in that BLOB or string.
3252** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
3253** the string to UTF-16 and then returns the number of bytes.
3254** ^If the result is a numeric value then sqlite3_column_bytes16() uses
3255** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
3256** the number of bytes in that string.
3257** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
3258**
3259** ^The values returned by [sqlite3_column_bytes()] and
3260** [sqlite3_column_bytes16()] do not include the zero terminators at the end
3261** of the string.  ^For clarity: the values returned by
3262** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
3263** bytes in the string, not the number of characters.
3264**
3265** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
3266** even empty strings, are always zero terminated.  ^The return
3267** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
3268**
3269** ^The object returned by [sqlite3_column_value()] is an
3270** [unprotected sqlite3_value] object.  An unprotected sqlite3_value object
3271** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()].
3272** If the [unprotected sqlite3_value] object returned by
3273** [sqlite3_column_value()] is used in any other way, including calls
3274** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
3275** or [sqlite3_value_bytes()], then the behavior is undefined.
3276**
3277** These routines attempt to convert the value where appropriate.  ^For
3278** example, if the internal representation is FLOAT and a text result
3279** is requested, [sqlite3_snprintf()] is used internally to perform the
3280** conversion automatically.  ^(The following table details the conversions
3281** that are applied:
3282**
3283** <blockquote>
3284** <table border="1">
3285** <tr><th> Internal<br>Type <th> Requested<br>Type <th>  Conversion
3286**
3287** <tr><td>  NULL    <td> INTEGER   <td> Result is 0
3288** <tr><td>  NULL    <td>  FLOAT    <td> Result is 0.0
3289** <tr><td>  NULL    <td>   TEXT    <td> Result is NULL pointer
3290** <tr><td>  NULL    <td>   BLOB    <td> Result is NULL pointer
3291** <tr><td> INTEGER  <td>  FLOAT    <td> Convert from integer to float
3292** <tr><td> INTEGER  <td>   TEXT    <td> ASCII rendering of the integer
3293** <tr><td> INTEGER  <td>   BLOB    <td> Same as INTEGER->TEXT
3294** <tr><td>  FLOAT   <td> INTEGER   <td> Convert from float to integer
3295** <tr><td>  FLOAT   <td>   TEXT    <td> ASCII rendering of the float
3296** <tr><td>  FLOAT   <td>   BLOB    <td> Same as FLOAT->TEXT
3297** <tr><td>  TEXT    <td> INTEGER   <td> Use atoi()
3298** <tr><td>  TEXT    <td>  FLOAT    <td> Use atof()
3299** <tr><td>  TEXT    <td>   BLOB    <td> No change
3300** <tr><td>  BLOB    <td> INTEGER   <td> Convert to TEXT then use atoi()
3301** <tr><td>  BLOB    <td>  FLOAT    <td> Convert to TEXT then use atof()
3302** <tr><td>  BLOB    <td>   TEXT    <td> Add a zero terminator if needed
3303** </table>
3304** </blockquote>)^
3305**
3306** The table above makes reference to standard C library functions atoi()
3307** and atof().  SQLite does not really use these functions.  It has its
3308** own equivalent internal routines.  The atoi() and atof() names are
3309** used in the table for brevity and because they are familiar to most
3310** C programmers.
3311**
3312** Note that when type conversions occur, pointers returned by prior
3313** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
3314** sqlite3_column_text16() may be invalidated.
3315** Type conversions and pointer invalidations might occur
3316** in the following cases:
3317**
3318** <ul>
3319** <li> The initial content is a BLOB and sqlite3_column_text() or
3320**      sqlite3_column_text16() is called.  A zero-terminator might
3321**      need to be added to the string.</li>
3322** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
3323**      sqlite3_column_text16() is called.  The content must be converted
3324**      to UTF-16.</li>
3325** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
3326**      sqlite3_column_text() is called.  The content must be converted
3327**      to UTF-8.</li>
3328** </ul>
3329**
3330** ^Conversions between UTF-16be and UTF-16le are always done in place and do
3331** not invalidate a prior pointer, though of course the content of the buffer
3332** that the prior pointer references will have been modified.  Other kinds
3333** of conversion are done in place when it is possible, but sometimes they
3334** are not possible and in those cases prior pointers are invalidated.
3335**
3336** The safest and easiest to remember policy is to invoke these routines
3337** in one of the following ways:
3338**
3339** <ul>
3340**  <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
3341**  <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
3342**  <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
3343** </ul>
3344**
3345** In other words, you should call sqlite3_column_text(),
3346** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
3347** into the desired format, then invoke sqlite3_column_bytes() or
3348** sqlite3_column_bytes16() to find the size of the result.  Do not mix calls
3349** to sqlite3_column_text() or sqlite3_column_blob() with calls to
3350** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
3351** with calls to sqlite3_column_bytes().
3352**
3353** ^The pointers returned are valid until a type conversion occurs as
3354** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
3355** [sqlite3_finalize()] is called.  ^The memory space used to hold strings
3356** and BLOBs is freed automatically.  Do <b>not</b> pass the pointers returned
3357** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
3358** [sqlite3_free()].
3359**
3360** ^(If a memory allocation error occurs during the evaluation of any
3361** of these routines, a default value is returned.  The default value
3362** is either the integer 0, the floating point number 0.0, or a NULL
3363** pointer.  Subsequent calls to [sqlite3_errcode()] will return
3364** [SQLITE_NOMEM].)^
3365*/
3366const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
3367int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
3368int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
3369double sqlite3_column_double(sqlite3_stmt*, int iCol);
3370int sqlite3_column_int(sqlite3_stmt*, int iCol);
3371sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
3372const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
3373const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
3374int sqlite3_column_type(sqlite3_stmt*, int iCol);
3375sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
3376
3377/*
3378** CAPI3REF: Destroy A Prepared Statement Object
3379**
3380** ^The sqlite3_finalize() function is called to delete a [prepared statement].
3381** ^If the most recent evaluation of the statement encountered no errors or
3382** or if the statement is never been evaluated, then sqlite3_finalize() returns
3383** SQLITE_OK.  ^If the most recent evaluation of statement S failed, then
3384** sqlite3_finalize(S) returns the appropriate [error code] or
3385** [extended error code].
3386**
3387** ^The sqlite3_finalize(S) routine can be called at any point during
3388** the life cycle of [prepared statement] S:
3389** before statement S is ever evaluated, after
3390** one or more calls to [sqlite3_reset()], or after any call
3391** to [sqlite3_step()] regardless of whether or not the statement has
3392** completed execution.
3393**
3394** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
3395**
3396** The application must finalize every [prepared statement] in order to avoid
3397** resource leaks.  It is a grievous error for the application to try to use
3398** a prepared statement after it has been finalized.  Any use of a prepared
3399** statement after it has been finalized can result in undefined and
3400** undesirable behavior such as segfaults and heap corruption.
3401*/
3402int sqlite3_finalize(sqlite3_stmt *pStmt);
3403
3404/*
3405** CAPI3REF: Reset A Prepared Statement Object
3406**
3407** The sqlite3_reset() function is called to reset a [prepared statement]
3408** object back to its initial state, ready to be re-executed.
3409** ^Any SQL statement variables that had values bound to them using
3410** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
3411** Use [sqlite3_clear_bindings()] to reset the bindings.
3412**
3413** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
3414** back to the beginning of its program.
3415**
3416** ^If the most recent call to [sqlite3_step(S)] for the
3417** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
3418** or if [sqlite3_step(S)] has never before been called on S,
3419** then [sqlite3_reset(S)] returns [SQLITE_OK].
3420**
3421** ^If the most recent call to [sqlite3_step(S)] for the
3422** [prepared statement] S indicated an error, then
3423** [sqlite3_reset(S)] returns an appropriate [error code].
3424**
3425** ^The [sqlite3_reset(S)] interface does not change the values
3426** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
3427*/
3428int sqlite3_reset(sqlite3_stmt *pStmt);
3429
3430/*
3431** CAPI3REF: Create Or Redefine SQL Functions
3432** KEYWORDS: {function creation routines}
3433** KEYWORDS: {application-defined SQL function}
3434** KEYWORDS: {application-defined SQL functions}
3435**
3436** ^These functions (collectively known as "function creation routines")
3437** are used to add SQL functions or aggregates or to redefine the behavior
3438** of existing SQL functions or aggregates.  The only differences between
3439** these routines are the text encoding expected for
3440** the second parameter (the name of the function being created)
3441** and the presence or absence of a destructor callback for
3442** the application data pointer.
3443**
3444** ^The first parameter is the [database connection] to which the SQL
3445** function is to be added.  ^If an application uses more than one database
3446** connection then application-defined SQL functions must be added
3447** to each database connection separately.
3448**
3449** ^The second parameter is the name of the SQL function to be created or
3450** redefined.  ^The length of the name is limited to 255 bytes in a UTF-8
3451** representation, exclusive of the zero-terminator.  ^Note that the name
3452** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
3453** ^Any attempt to create a function with a longer name
3454** will result in [SQLITE_MISUSE] being returned.
3455**
3456** ^The third parameter (nArg)
3457** is the number of arguments that the SQL function or
3458** aggregate takes. ^If this parameter is -1, then the SQL function or
3459** aggregate may take any number of arguments between 0 and the limit
3460** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]).  If the third
3461** parameter is less than -1 or greater than 127 then the behavior is
3462** undefined.
3463**
3464** ^The fourth parameter, eTextRep, specifies what
3465** [SQLITE_UTF8 | text encoding] this SQL function prefers for
3466** its parameters.  Every SQL function implementation must be able to work
3467** with UTF-8, UTF-16le, or UTF-16be.  But some implementations may be
3468** more efficient with one encoding than another.  ^An application may
3469** invoke sqlite3_create_function() or sqlite3_create_function16() multiple
3470** times with the same function but with different values of eTextRep.
3471** ^When multiple implementations of the same function are available, SQLite
3472** will pick the one that involves the least amount of data conversion.
3473** If there is only a single implementation which does not care what text
3474** encoding is used, then the fourth argument should be [SQLITE_ANY].
3475**
3476** ^(The fifth parameter is an arbitrary pointer.  The implementation of the
3477** function can gain access to this pointer using [sqlite3_user_data()].)^
3478**
3479** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are
3480** pointers to C-language functions that implement the SQL function or
3481** aggregate. ^A scalar SQL function requires an implementation of the xFunc
3482** callback only; NULL pointers must be passed as the xStep and xFinal
3483** parameters. ^An aggregate SQL function requires an implementation of xStep
3484** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
3485** SQL function or aggregate, pass NULL pointers for all three function
3486** callbacks.
3487**
3488** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL,
3489** then it is destructor for the application data pointer.
3490** The destructor is invoked when the function is deleted, either by being
3491** overloaded or when the database connection closes.)^
3492** ^The destructor is also invoked if the call to
3493** sqlite3_create_function_v2() fails.
3494** ^When the destructor callback of the tenth parameter is invoked, it
3495** is passed a single argument which is a copy of the application data
3496** pointer which was the fifth parameter to sqlite3_create_function_v2().
3497**
3498** ^It is permitted to register multiple implementations of the same
3499** functions with the same name but with either differing numbers of
3500** arguments or differing preferred text encodings.  ^SQLite will use
3501** the implementation that most closely matches the way in which the
3502** SQL function is used.  ^A function implementation with a non-negative
3503** nArg parameter is a better match than a function implementation with
3504** a negative nArg.  ^A function where the preferred text encoding
3505** matches the database encoding is a better
3506** match than a function where the encoding is different.
3507** ^A function where the encoding difference is between UTF16le and UTF16be
3508** is a closer match than a function where the encoding difference is
3509** between UTF8 and UTF16.
3510**
3511** ^Built-in functions may be overloaded by new application-defined functions.
3512**
3513** ^An application-defined function is permitted to call other
3514** SQLite interfaces.  However, such calls must not
3515** close the database connection nor finalize or reset the prepared
3516** statement in which the function is running.
3517*/
3518int sqlite3_create_function(
3519  sqlite3 *db,
3520  const char *zFunctionName,
3521  int nArg,
3522  int eTextRep,
3523  void *pApp,
3524  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
3525  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
3526  void (*xFinal)(sqlite3_context*)
3527);
3528int sqlite3_create_function16(
3529  sqlite3 *db,
3530  const void *zFunctionName,
3531  int nArg,
3532  int eTextRep,
3533  void *pApp,
3534  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
3535  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
3536  void (*xFinal)(sqlite3_context*)
3537);
3538int sqlite3_create_function_v2(
3539  sqlite3 *db,
3540  const char *zFunctionName,
3541  int nArg,
3542  int eTextRep,
3543  void *pApp,
3544  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
3545  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
3546  void (*xFinal)(sqlite3_context*),
3547  void(*xDestroy)(void*)
3548);
3549
3550/*
3551** CAPI3REF: Text Encodings
3552**
3553** These constant define integer codes that represent the various
3554** text encodings supported by SQLite.
3555*/
3556#define SQLITE_UTF8           1
3557#define SQLITE_UTF16LE        2
3558#define SQLITE_UTF16BE        3
3559#define SQLITE_UTF16          4    /* Use native byte order */
3560#define SQLITE_ANY            5    /* sqlite3_create_function only */
3561#define SQLITE_UTF16_ALIGNED  8    /* sqlite3_create_collation only */
3562
3563/*
3564** CAPI3REF: Deprecated Functions
3565** DEPRECATED
3566**
3567** These functions are [deprecated].  In order to maintain
3568** backwards compatibility with older code, these functions continue
3569** to be supported.  However, new applications should avoid
3570** the use of these functions.  To help encourage people to avoid
3571** using these functions, we are not going to tell you what they do.
3572*/
3573#ifndef SQLITE_OMIT_DEPRECATED
3574SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
3575SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
3576SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
3577SQLITE_DEPRECATED int sqlite3_global_recover(void);
3578SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
3579SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64);
3580#endif
3581
3582/*
3583** CAPI3REF: Obtaining SQL Function Parameter Values
3584**
3585** The C-language implementation of SQL functions and aggregates uses
3586** this set of interface routines to access the parameter values on
3587** the function or aggregate.
3588**
3589** The xFunc (for scalar functions) or xStep (for aggregates) parameters
3590** to [sqlite3_create_function()] and [sqlite3_create_function16()]
3591** define callbacks that implement the SQL functions and aggregates.
3592** The 3rd parameter to these callbacks is an array of pointers to
3593** [protected sqlite3_value] objects.  There is one [sqlite3_value] object for
3594** each parameter to the SQL function.  These routines are used to
3595** extract values from the [sqlite3_value] objects.
3596**
3597** These routines work only with [protected sqlite3_value] objects.
3598** Any attempt to use these routines on an [unprotected sqlite3_value]
3599** object results in undefined behavior.
3600**
3601** ^These routines work just like the corresponding [column access functions]
3602** except that  these routines take a single [protected sqlite3_value] object
3603** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
3604**
3605** ^The sqlite3_value_text16() interface extracts a UTF-16 string
3606** in the native byte-order of the host machine.  ^The
3607** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
3608** extract UTF-16 strings as big-endian and little-endian respectively.
3609**
3610** ^(The sqlite3_value_numeric_type() interface attempts to apply
3611** numeric affinity to the value.  This means that an attempt is
3612** made to convert the value to an integer or floating point.  If
3613** such a conversion is possible without loss of information (in other
3614** words, if the value is a string that looks like a number)
3615** then the conversion is performed.  Otherwise no conversion occurs.
3616** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
3617**
3618** Please pay particular attention to the fact that the pointer returned
3619** from [sqlite3_value_blob()], [sqlite3_value_text()], or
3620** [sqlite3_value_text16()] can be invalidated by a subsequent call to
3621** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
3622** or [sqlite3_value_text16()].
3623**
3624** These routines must be called from the same thread as
3625** the SQL function that supplied the [sqlite3_value*] parameters.
3626*/
3627const void *sqlite3_value_blob(sqlite3_value*);
3628int sqlite3_value_bytes(sqlite3_value*);
3629int sqlite3_value_bytes16(sqlite3_value*);
3630double sqlite3_value_double(sqlite3_value*);
3631int sqlite3_value_int(sqlite3_value*);
3632sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
3633const unsigned char *sqlite3_value_text(sqlite3_value*);
3634const void *sqlite3_value_text16(sqlite3_value*);
3635const void *sqlite3_value_text16le(sqlite3_value*);
3636const void *sqlite3_value_text16be(sqlite3_value*);
3637int sqlite3_value_type(sqlite3_value*);
3638int sqlite3_value_numeric_type(sqlite3_value*);
3639
3640/*
3641** CAPI3REF: Obtain Aggregate Function Context
3642**
3643** Implementations of aggregate SQL functions use this
3644** routine to allocate memory for storing their state.
3645**
3646** ^The first time the sqlite3_aggregate_context(C,N) routine is called
3647** for a particular aggregate function, SQLite
3648** allocates N of memory, zeroes out that memory, and returns a pointer
3649** to the new memory. ^On second and subsequent calls to
3650** sqlite3_aggregate_context() for the same aggregate function instance,
3651** the same buffer is returned.  Sqlite3_aggregate_context() is normally
3652** called once for each invocation of the xStep callback and then one
3653** last time when the xFinal callback is invoked.  ^(When no rows match
3654** an aggregate query, the xStep() callback of the aggregate function
3655** implementation is never called and xFinal() is called exactly once.
3656** In those cases, sqlite3_aggregate_context() might be called for the
3657** first time from within xFinal().)^
3658**
3659** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer if N is
3660** less than or equal to zero or if a memory allocate error occurs.
3661**
3662** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
3663** determined by the N parameter on first successful call.  Changing the
3664** value of N in subsequent call to sqlite3_aggregate_context() within
3665** the same aggregate function instance will not resize the memory
3666** allocation.)^
3667**
3668** ^SQLite automatically frees the memory allocated by
3669** sqlite3_aggregate_context() when the aggregate query concludes.
3670**
3671** The first parameter must be a copy of the
3672** [sqlite3_context | SQL function context] that is the first parameter
3673** to the xStep or xFinal callback routine that implements the aggregate
3674** function.
3675**
3676** This routine must be called from the same thread in which
3677** the aggregate SQL function is running.
3678*/
3679void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
3680
3681/*
3682** CAPI3REF: User Data For Functions
3683**
3684** ^The sqlite3_user_data() interface returns a copy of
3685** the pointer that was the pUserData parameter (the 5th parameter)
3686** of the [sqlite3_create_function()]
3687** and [sqlite3_create_function16()] routines that originally
3688** registered the application defined function.
3689**
3690** This routine must be called from the same thread in which
3691** the application-defined function is running.
3692*/
3693void *sqlite3_user_data(sqlite3_context*);
3694
3695/*
3696** CAPI3REF: Database Connection For Functions
3697**
3698** ^The sqlite3_context_db_handle() interface returns a copy of
3699** the pointer to the [database connection] (the 1st parameter)
3700** of the [sqlite3_create_function()]
3701** and [sqlite3_create_function16()] routines that originally
3702** registered the application defined function.
3703*/
3704sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
3705
3706/*
3707** CAPI3REF: Function Auxiliary Data
3708**
3709** The following two functions may be used by scalar SQL functions to
3710** associate metadata with argument values. If the same value is passed to
3711** multiple invocations of the same SQL function during query execution, under
3712** some circumstances the associated metadata may be preserved. This may
3713** be used, for example, to add a regular-expression matching scalar
3714** function. The compiled version of the regular expression is stored as
3715** metadata associated with the SQL value passed as the regular expression
3716** pattern.  The compiled regular expression can be reused on multiple
3717** invocations of the same function so that the original pattern string
3718** does not need to be recompiled on each invocation.
3719**
3720** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata
3721** associated by the sqlite3_set_auxdata() function with the Nth argument
3722** value to the application-defined function. ^If no metadata has been ever
3723** been set for the Nth argument of the function, or if the corresponding
3724** function parameter has changed since the meta-data was set,
3725** then sqlite3_get_auxdata() returns a NULL pointer.
3726**
3727** ^The sqlite3_set_auxdata() interface saves the metadata
3728** pointed to by its 3rd parameter as the metadata for the N-th
3729** argument of the application-defined function.  Subsequent
3730** calls to sqlite3_get_auxdata() might return this data, if it has
3731** not been destroyed.
3732** ^If it is not NULL, SQLite will invoke the destructor
3733** function given by the 4th parameter to sqlite3_set_auxdata() on
3734** the metadata when the corresponding function parameter changes
3735** or when the SQL statement completes, whichever comes first.
3736**
3737** SQLite is free to call the destructor and drop metadata on any
3738** parameter of any function at any time.  ^The only guarantee is that
3739** the destructor will be called before the metadata is dropped.
3740**
3741** ^(In practice, metadata is preserved between function calls for
3742** expressions that are constant at compile time. This includes literal
3743** values and [parameters].)^
3744**
3745** These routines must be called from the same thread in which
3746** the SQL function is running.
3747*/
3748void *sqlite3_get_auxdata(sqlite3_context*, int N);
3749void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
3750
3751
3752/*
3753** CAPI3REF: Constants Defining Special Destructor Behavior
3754**
3755** These are special values for the destructor that is passed in as the
3756** final argument to routines like [sqlite3_result_blob()].  ^If the destructor
3757** argument is SQLITE_STATIC, it means that the content pointer is constant
3758** and will never change.  It does not need to be destroyed.  ^The
3759** SQLITE_TRANSIENT value means that the content will likely change in
3760** the near future and that SQLite should make its own private copy of
3761** the content before returning.
3762**
3763** The typedef is necessary to work around problems in certain
3764** C++ compilers.  See ticket #2191.
3765*/
3766typedef void (*sqlite3_destructor_type)(void*);
3767#define SQLITE_STATIC      ((sqlite3_destructor_type)0)
3768#define SQLITE_TRANSIENT   ((sqlite3_destructor_type)-1)
3769
3770/*
3771** CAPI3REF: Setting The Result Of An SQL Function
3772**
3773** These routines are used by the xFunc or xFinal callbacks that
3774** implement SQL functions and aggregates.  See
3775** [sqlite3_create_function()] and [sqlite3_create_function16()]
3776** for additional information.
3777**
3778** These functions work very much like the [parameter binding] family of
3779** functions used to bind values to host parameters in prepared statements.
3780** Refer to the [SQL parameter] documentation for additional information.
3781**
3782** ^The sqlite3_result_blob() interface sets the result from
3783** an application-defined function to be the BLOB whose content is pointed
3784** to by the second parameter and which is N bytes long where N is the
3785** third parameter.
3786**
3787** ^The sqlite3_result_zeroblob() interfaces set the result of
3788** the application-defined function to be a BLOB containing all zero
3789** bytes and N bytes in size, where N is the value of the 2nd parameter.
3790**
3791** ^The sqlite3_result_double() interface sets the result from
3792** an application-defined function to be a floating point value specified
3793** by its 2nd argument.
3794**
3795** ^The sqlite3_result_error() and sqlite3_result_error16() functions
3796** cause the implemented SQL function to throw an exception.
3797** ^SQLite uses the string pointed to by the
3798** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
3799** as the text of an error message.  ^SQLite interprets the error
3800** message string from sqlite3_result_error() as UTF-8. ^SQLite
3801** interprets the string from sqlite3_result_error16() as UTF-16 in native
3802** byte order.  ^If the third parameter to sqlite3_result_error()
3803** or sqlite3_result_error16() is negative then SQLite takes as the error
3804** message all text up through the first zero character.
3805** ^If the third parameter to sqlite3_result_error() or
3806** sqlite3_result_error16() is non-negative then SQLite takes that many
3807** bytes (not characters) from the 2nd parameter as the error message.
3808** ^The sqlite3_result_error() and sqlite3_result_error16()
3809** routines make a private copy of the error message text before
3810** they return.  Hence, the calling function can deallocate or
3811** modify the text after they return without harm.
3812** ^The sqlite3_result_error_code() function changes the error code
3813** returned by SQLite as a result of an error in a function.  ^By default,
3814** the error code is SQLITE_ERROR.  ^A subsequent call to sqlite3_result_error()
3815** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
3816**
3817** ^The sqlite3_result_toobig() interface causes SQLite to throw an error
3818** indicating that a string or BLOB is too long to represent.
3819**
3820** ^The sqlite3_result_nomem() interface causes SQLite to throw an error
3821** indicating that a memory allocation failed.
3822**
3823** ^The sqlite3_result_int() interface sets the return value
3824** of the application-defined function to be the 32-bit signed integer
3825** value given in the 2nd argument.
3826** ^The sqlite3_result_int64() interface sets the return value
3827** of the application-defined function to be the 64-bit signed integer
3828** value given in the 2nd argument.
3829**
3830** ^The sqlite3_result_null() interface sets the return value
3831** of the application-defined function to be NULL.
3832**
3833** ^The sqlite3_result_text(), sqlite3_result_text16(),
3834** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
3835** set the return value of the application-defined function to be
3836** a text string which is represented as UTF-8, UTF-16 native byte order,
3837** UTF-16 little endian, or UTF-16 big endian, respectively.
3838** ^SQLite takes the text result from the application from
3839** the 2nd parameter of the sqlite3_result_text* interfaces.
3840** ^If the 3rd parameter to the sqlite3_result_text* interfaces
3841** is negative, then SQLite takes result text from the 2nd parameter
3842** through the first zero character.
3843** ^If the 3rd parameter to the sqlite3_result_text* interfaces
3844** is non-negative, then as many bytes (not characters) of the text
3845** pointed to by the 2nd parameter are taken as the application-defined
3846** function result.
3847** ^If the 4th parameter to the sqlite3_result_text* interfaces
3848** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
3849** function as the destructor on the text or BLOB result when it has
3850** finished using that result.
3851** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
3852** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
3853** assumes that the text or BLOB result is in constant space and does not
3854** copy the content of the parameter nor call a destructor on the content
3855** when it has finished using that result.
3856** ^If the 4th parameter to the sqlite3_result_text* interfaces
3857** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
3858** then SQLite makes a copy of the result into space obtained from
3859** from [sqlite3_malloc()] before it returns.
3860**
3861** ^The sqlite3_result_value() interface sets the result of
3862** the application-defined function to be a copy the
3863** [unprotected sqlite3_value] object specified by the 2nd parameter.  ^The
3864** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
3865** so that the [sqlite3_value] specified in the parameter may change or
3866** be deallocated after sqlite3_result_value() returns without harm.
3867** ^A [protected sqlite3_value] object may always be used where an
3868** [unprotected sqlite3_value] object is required, so either
3869** kind of [sqlite3_value] object can be used with this interface.
3870**
3871** If these routines are called from within the different thread
3872** than the one containing the application-defined function that received
3873** the [sqlite3_context] pointer, the results are undefined.
3874*/
3875void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
3876void sqlite3_result_double(sqlite3_context*, double);
3877void sqlite3_result_error(sqlite3_context*, const char*, int);
3878void sqlite3_result_error16(sqlite3_context*, const void*, int);
3879void sqlite3_result_error_toobig(sqlite3_context*);
3880void sqlite3_result_error_nomem(sqlite3_context*);
3881void sqlite3_result_error_code(sqlite3_context*, int);
3882void sqlite3_result_int(sqlite3_context*, int);
3883void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
3884void sqlite3_result_null(sqlite3_context*);
3885void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
3886void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
3887void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
3888void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
3889void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
3890void sqlite3_result_zeroblob(sqlite3_context*, int n);
3891
3892/*
3893** CAPI3REF: Define New Collating Sequences
3894**
3895** ^These functions add, remove, or modify a [collation] associated
3896** with the [database connection] specified as the first argument.
3897**
3898** ^The name of the collation is a UTF-8 string
3899** for sqlite3_create_collation() and sqlite3_create_collation_v2()
3900** and a UTF-16 string in native byte order for sqlite3_create_collation16().
3901** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
3902** considered to be the same name.
3903**
3904** ^(The third argument (eTextRep) must be one of the constants:
3905** <ul>
3906** <li> [SQLITE_UTF8],
3907** <li> [SQLITE_UTF16LE],
3908** <li> [SQLITE_UTF16BE],
3909** <li> [SQLITE_UTF16], or
3910** <li> [SQLITE_UTF16_ALIGNED].
3911** </ul>)^
3912** ^The eTextRep argument determines the encoding of strings passed
3913** to the collating function callback, xCallback.
3914** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
3915** force strings to be UTF16 with native byte order.
3916** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
3917** on an even byte address.
3918**
3919** ^The fourth argument, pArg, is an application data pointer that is passed
3920** through as the first argument to the collating function callback.
3921**
3922** ^The fifth argument, xCallback, is a pointer to the collating function.
3923** ^Multiple collating functions can be registered using the same name but
3924** with different eTextRep parameters and SQLite will use whichever
3925** function requires the least amount of data transformation.
3926** ^If the xCallback argument is NULL then the collating function is
3927** deleted.  ^When all collating functions having the same name are deleted,
3928** that collation is no longer usable.
3929**
3930** ^The collating function callback is invoked with a copy of the pArg
3931** application data pointer and with two strings in the encoding specified
3932** by the eTextRep argument.  The collating function must return an
3933** integer that is negative, zero, or positive
3934** if the first string is less than, equal to, or greater than the second,
3935** respectively.  A collating function must always return the same answer
3936** given the same inputs.  If two or more collating functions are registered
3937** to the same collation name (using different eTextRep values) then all
3938** must give an equivalent answer when invoked with equivalent strings.
3939** The collating function must obey the following properties for all
3940** strings A, B, and C:
3941**
3942** <ol>
3943** <li> If A==B then B==A.
3944** <li> If A==B and B==C then A==C.
3945** <li> If A&lt;B THEN B&gt;A.
3946** <li> If A&lt;B and B&lt;C then A&lt;C.
3947** </ol>
3948**
3949** If a collating function fails any of the above constraints and that
3950** collating function is  registered and used, then the behavior of SQLite
3951** is undefined.
3952**
3953** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
3954** with the addition that the xDestroy callback is invoked on pArg when
3955** the collating function is deleted.
3956** ^Collating functions are deleted when they are overridden by later
3957** calls to the collation creation functions or when the
3958** [database connection] is closed using [sqlite3_close()].
3959**
3960** ^The xDestroy callback is <u>not</u> called if the
3961** sqlite3_create_collation_v2() function fails.  Applications that invoke
3962** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
3963** check the return code and dispose of the application data pointer
3964** themselves rather than expecting SQLite to deal with it for them.
3965** This is different from every other SQLite interface.  The inconsistency
3966** is unfortunate but cannot be changed without breaking backwards
3967** compatibility.
3968**
3969** See also:  [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
3970*/
3971int sqlite3_create_collation(
3972  sqlite3*,
3973  const char *zName,
3974  int eTextRep,
3975  void *pArg,
3976  int(*xCompare)(void*,int,const void*,int,const void*)
3977);
3978int sqlite3_create_collation_v2(
3979  sqlite3*,
3980  const char *zName,
3981  int eTextRep,
3982  void *pArg,
3983  int(*xCompare)(void*,int,const void*,int,const void*),
3984  void(*xDestroy)(void*)
3985);
3986int sqlite3_create_collation16(
3987  sqlite3*,
3988  const void *zName,
3989  int eTextRep,
3990  void *pArg,
3991  int(*xCompare)(void*,int,const void*,int,const void*)
3992);
3993
3994/*
3995** CAPI3REF: Collation Needed Callbacks
3996**
3997** ^To avoid having to register all collation sequences before a database
3998** can be used, a single callback function may be registered with the
3999** [database connection] to be invoked whenever an undefined collation
4000** sequence is required.
4001**
4002** ^If the function is registered using the sqlite3_collation_needed() API,
4003** then it is passed the names of undefined collation sequences as strings
4004** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
4005** the names are passed as UTF-16 in machine native byte order.
4006** ^A call to either function replaces the existing collation-needed callback.
4007**
4008** ^(When the callback is invoked, the first argument passed is a copy
4009** of the second argument to sqlite3_collation_needed() or
4010** sqlite3_collation_needed16().  The second argument is the database
4011** connection.  The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
4012** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
4013** sequence function required.  The fourth parameter is the name of the
4014** required collation sequence.)^
4015**
4016** The callback function should register the desired collation using
4017** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
4018** [sqlite3_create_collation_v2()].
4019*/
4020int sqlite3_collation_needed(
4021  sqlite3*,
4022  void*,
4023  void(*)(void*,sqlite3*,int eTextRep,const char*)
4024);
4025int sqlite3_collation_needed16(
4026  sqlite3*,
4027  void*,
4028  void(*)(void*,sqlite3*,int eTextRep,const void*)
4029);
4030
4031#ifdef SQLITE_HAS_CODEC
4032/*
4033** Specify the key for an encrypted database.  This routine should be
4034** called right after sqlite3_open().
4035**
4036** The code to implement this API is not available in the public release
4037** of SQLite.
4038*/
4039int sqlite3_key(
4040  sqlite3 *db,                   /* Database to be rekeyed */
4041  const void *pKey, int nKey     /* The key */
4042);
4043
4044/*
4045** Change the key on an open database.  If the current database is not
4046** encrypted, this routine will encrypt it.  If pNew==0 or nNew==0, the
4047** database is decrypted.
4048**
4049** The code to implement this API is not available in the public release
4050** of SQLite.
4051*/
4052int sqlite3_rekey(
4053  sqlite3 *db,                   /* Database to be rekeyed */
4054  const void *pKey, int nKey     /* The new key */
4055);
4056
4057/*
4058** Specify the activation key for a SEE database.  Unless
4059** activated, none of the SEE routines will work.
4060*/
4061void sqlite3_activate_see(
4062  const char *zPassPhrase        /* Activation phrase */
4063);
4064#endif
4065
4066#ifdef SQLITE_ENABLE_CEROD
4067/*
4068** Specify the activation key for a CEROD database.  Unless
4069** activated, none of the CEROD routines will work.
4070*/
4071void sqlite3_activate_cerod(
4072  const char *zPassPhrase        /* Activation phrase */
4073);
4074#endif
4075
4076/*
4077** CAPI3REF: Suspend Execution For A Short Time
4078**
4079** The sqlite3_sleep() function causes the current thread to suspend execution
4080** for at least a number of milliseconds specified in its parameter.
4081**
4082** If the operating system does not support sleep requests with
4083** millisecond time resolution, then the time will be rounded up to
4084** the nearest second. The number of milliseconds of sleep actually
4085** requested from the operating system is returned.
4086**
4087** ^SQLite implements this interface by calling the xSleep()
4088** method of the default [sqlite3_vfs] object.  If the xSleep() method
4089** of the default VFS is not implemented correctly, or not implemented at
4090** all, then the behavior of sqlite3_sleep() may deviate from the description
4091** in the previous paragraphs.
4092*/
4093int sqlite3_sleep(int);
4094
4095/*
4096** CAPI3REF: Name Of The Folder Holding Temporary Files
4097**
4098** ^(If this global variable is made to point to a string which is
4099** the name of a folder (a.k.a. directory), then all temporary files
4100** created by SQLite when using a built-in [sqlite3_vfs | VFS]
4101** will be placed in that directory.)^  ^If this variable
4102** is a NULL pointer, then SQLite performs a search for an appropriate
4103** temporary file directory.
4104**
4105** It is not safe to read or modify this variable in more than one
4106** thread at a time.  It is not safe to read or modify this variable
4107** if a [database connection] is being used at the same time in a separate
4108** thread.
4109** It is intended that this variable be set once
4110** as part of process initialization and before any SQLite interface
4111** routines have been called and that this variable remain unchanged
4112** thereafter.
4113**
4114** ^The [temp_store_directory pragma] may modify this variable and cause
4115** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
4116** the [temp_store_directory pragma] always assumes that any string
4117** that this variable points to is held in memory obtained from
4118** [sqlite3_malloc] and the pragma may attempt to free that memory
4119** using [sqlite3_free].
4120** Hence, if this variable is modified directly, either it should be
4121** made NULL or made to point to memory obtained from [sqlite3_malloc]
4122** or else the use of the [temp_store_directory pragma] should be avoided.
4123*/
4124SQLITE_EXTERN char *sqlite3_temp_directory;
4125
4126/*
4127** CAPI3REF: Test For Auto-Commit Mode
4128** KEYWORDS: {autocommit mode}
4129**
4130** ^The sqlite3_get_autocommit() interface returns non-zero or
4131** zero if the given database connection is or is not in autocommit mode,
4132** respectively.  ^Autocommit mode is on by default.
4133** ^Autocommit mode is disabled by a [BEGIN] statement.
4134** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
4135**
4136** If certain kinds of errors occur on a statement within a multi-statement
4137** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
4138** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
4139** transaction might be rolled back automatically.  The only way to
4140** find out whether SQLite automatically rolled back the transaction after
4141** an error is to use this function.
4142**
4143** If another thread changes the autocommit status of the database
4144** connection while this routine is running, then the return value
4145** is undefined.
4146*/
4147int sqlite3_get_autocommit(sqlite3*);
4148
4149/*
4150** CAPI3REF: Find The Database Handle Of A Prepared Statement
4151**
4152** ^The sqlite3_db_handle interface returns the [database connection] handle
4153** to which a [prepared statement] belongs.  ^The [database connection]
4154** returned by sqlite3_db_handle is the same [database connection]
4155** that was the first argument
4156** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
4157** create the statement in the first place.
4158*/
4159sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
4160
4161/*
4162** CAPI3REF: Find the next prepared statement
4163**
4164** ^This interface returns a pointer to the next [prepared statement] after
4165** pStmt associated with the [database connection] pDb.  ^If pStmt is NULL
4166** then this interface returns a pointer to the first prepared statement
4167** associated with the database connection pDb.  ^If no prepared statement
4168** satisfies the conditions of this routine, it returns NULL.
4169**
4170** The [database connection] pointer D in a call to
4171** [sqlite3_next_stmt(D,S)] must refer to an open database
4172** connection and in particular must not be a NULL pointer.
4173*/
4174sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
4175
4176/*
4177** CAPI3REF: Commit And Rollback Notification Callbacks
4178**
4179** ^The sqlite3_commit_hook() interface registers a callback
4180** function to be invoked whenever a transaction is [COMMIT | committed].
4181** ^Any callback set by a previous call to sqlite3_commit_hook()
4182** for the same database connection is overridden.
4183** ^The sqlite3_rollback_hook() interface registers a callback
4184** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
4185** ^Any callback set by a previous call to sqlite3_rollback_hook()
4186** for the same database connection is overridden.
4187** ^The pArg argument is passed through to the callback.
4188** ^If the callback on a commit hook function returns non-zero,
4189** then the commit is converted into a rollback.
4190**
4191** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
4192** return the P argument from the previous call of the same function
4193** on the same [database connection] D, or NULL for
4194** the first call for each function on D.
4195**
4196** The callback implementation must not do anything that will modify
4197** the database connection that invoked the callback.  Any actions
4198** to modify the database connection must be deferred until after the
4199** completion of the [sqlite3_step()] call that triggered the commit
4200** or rollback hook in the first place.
4201** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
4202** database connections for the meaning of "modify" in this paragraph.
4203**
4204** ^Registering a NULL function disables the callback.
4205**
4206** ^When the commit hook callback routine returns zero, the [COMMIT]
4207** operation is allowed to continue normally.  ^If the commit hook
4208** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
4209** ^The rollback hook is invoked on a rollback that results from a commit
4210** hook returning non-zero, just as it would be with any other rollback.
4211**
4212** ^For the purposes of this API, a transaction is said to have been
4213** rolled back if an explicit "ROLLBACK" statement is executed, or
4214** an error or constraint causes an implicit rollback to occur.
4215** ^The rollback callback is not invoked if a transaction is
4216** automatically rolled back because the database connection is closed.
4217**
4218** See also the [sqlite3_update_hook()] interface.
4219*/
4220void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
4221void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
4222
4223/*
4224** CAPI3REF: Data Change Notification Callbacks
4225**
4226** ^The sqlite3_update_hook() interface registers a callback function
4227** with the [database connection] identified by the first argument
4228** to be invoked whenever a row is updated, inserted or deleted.
4229** ^Any callback set by a previous call to this function
4230** for the same database connection is overridden.
4231**
4232** ^The second argument is a pointer to the function to invoke when a
4233** row is updated, inserted or deleted.
4234** ^The first argument to the callback is a copy of the third argument
4235** to sqlite3_update_hook().
4236** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
4237** or [SQLITE_UPDATE], depending on the operation that caused the callback
4238** to be invoked.
4239** ^The third and fourth arguments to the callback contain pointers to the
4240** database and table name containing the affected row.
4241** ^The final callback parameter is the [rowid] of the row.
4242** ^In the case of an update, this is the [rowid] after the update takes place.
4243**
4244** ^(The update hook is not invoked when internal system tables are
4245** modified (i.e. sqlite_master and sqlite_sequence).)^
4246**
4247** ^In the current implementation, the update hook
4248** is not invoked when duplication rows are deleted because of an
4249** [ON CONFLICT | ON CONFLICT REPLACE] clause.  ^Nor is the update hook
4250** invoked when rows are deleted using the [truncate optimization].
4251** The exceptions defined in this paragraph might change in a future
4252** release of SQLite.
4253**
4254** The update hook implementation must not do anything that will modify
4255** the database connection that invoked the update hook.  Any actions
4256** to modify the database connection must be deferred until after the
4257** completion of the [sqlite3_step()] call that triggered the update hook.
4258** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
4259** database connections for the meaning of "modify" in this paragraph.
4260**
4261** ^The sqlite3_update_hook(D,C,P) function
4262** returns the P argument from the previous call
4263** on the same [database connection] D, or NULL for
4264** the first call on D.
4265**
4266** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()]
4267** interfaces.
4268*/
4269void *sqlite3_update_hook(
4270  sqlite3*,
4271  void(*)(void *,int ,char const *,char const *,sqlite3_int64),
4272  void*
4273);
4274
4275/*
4276** CAPI3REF: Enable Or Disable Shared Pager Cache
4277** KEYWORDS: {shared cache}
4278**
4279** ^(This routine enables or disables the sharing of the database cache
4280** and schema data structures between [database connection | connections]
4281** to the same database. Sharing is enabled if the argument is true
4282** and disabled if the argument is false.)^
4283**
4284** ^Cache sharing is enabled and disabled for an entire process.
4285** This is a change as of SQLite version 3.5.0. In prior versions of SQLite,
4286** sharing was enabled or disabled for each thread separately.
4287**
4288** ^(The cache sharing mode set by this interface effects all subsequent
4289** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
4290** Existing database connections continue use the sharing mode
4291** that was in effect at the time they were opened.)^
4292**
4293** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
4294** successfully.  An [error code] is returned otherwise.)^
4295**
4296** ^Shared cache is disabled by default. But this might change in
4297** future releases of SQLite.  Applications that care about shared
4298** cache setting should set it explicitly.
4299**
4300** See Also:  [SQLite Shared-Cache Mode]
4301*/
4302int sqlite3_enable_shared_cache(int);
4303
4304/*
4305** CAPI3REF: Attempt To Free Heap Memory
4306**
4307** ^The sqlite3_release_memory() interface attempts to free N bytes
4308** of heap memory by deallocating non-essential memory allocations
4309** held by the database library.   Memory used to cache database
4310** pages to improve performance is an example of non-essential memory.
4311** ^sqlite3_release_memory() returns the number of bytes actually freed,
4312** which might be more or less than the amount requested.
4313** ^The sqlite3_release_memory() routine is a no-op returning zero
4314** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
4315*/
4316int sqlite3_release_memory(int);
4317
4318/*
4319** CAPI3REF: Impose A Limit On Heap Size
4320**
4321** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
4322** soft limit on the amount of heap memory that may be allocated by SQLite.
4323** ^SQLite strives to keep heap memory utilization below the soft heap
4324** limit by reducing the number of pages held in the page cache
4325** as heap memory usages approaches the limit.
4326** ^The soft heap limit is "soft" because even though SQLite strives to stay
4327** below the limit, it will exceed the limit rather than generate
4328** an [SQLITE_NOMEM] error.  In other words, the soft heap limit
4329** is advisory only.
4330**
4331** ^The return value from sqlite3_soft_heap_limit64() is the size of
4332** the soft heap limit prior to the call.  ^If the argument N is negative
4333** then no change is made to the soft heap limit.  Hence, the current
4334** size of the soft heap limit can be determined by invoking
4335** sqlite3_soft_heap_limit64() with a negative argument.
4336**
4337** ^If the argument N is zero then the soft heap limit is disabled.
4338**
4339** ^(The soft heap limit is not enforced in the current implementation
4340** if one or more of following conditions are true:
4341**
4342** <ul>
4343** <li> The soft heap limit is set to zero.
4344** <li> Memory accounting is disabled using a combination of the
4345**      [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
4346**      the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
4347** <li> An alternative page cache implementation is specified using
4348**      [sqlite3_config]([SQLITE_CONFIG_PCACHE],...).
4349** <li> The page cache allocates from its own memory pool supplied
4350**      by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
4351**      from the heap.
4352** </ul>)^
4353**
4354** Beginning with SQLite version 3.7.3, the soft heap limit is enforced
4355** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT]
4356** compile-time option is invoked.  With [SQLITE_ENABLE_MEMORY_MANAGEMENT],
4357** the soft heap limit is enforced on every memory allocation.  Without
4358** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced
4359** when memory is allocated by the page cache.  Testing suggests that because
4360** the page cache is the predominate memory user in SQLite, most
4361** applications will achieve adequate soft heap limit enforcement without
4362** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT].
4363**
4364** The circumstances under which SQLite will enforce the soft heap limit may
4365** changes in future releases of SQLite.
4366*/
4367sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);
4368
4369/*
4370** CAPI3REF: Deprecated Soft Heap Limit Interface
4371** DEPRECATED
4372**
4373** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
4374** interface.  This routine is provided for historical compatibility
4375** only.  All new applications should use the
4376** [sqlite3_soft_heap_limit64()] interface rather than this one.
4377*/
4378SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N);
4379
4380
4381/*
4382** CAPI3REF: Extract Metadata About A Column Of A Table
4383**
4384** ^This routine returns metadata about a specific column of a specific
4385** database table accessible using the [database connection] handle
4386** passed as the first function argument.
4387**
4388** ^The column is identified by the second, third and fourth parameters to
4389** this function. ^The second parameter is either the name of the database
4390** (i.e. "main", "temp", or an attached database) containing the specified
4391** table or NULL. ^If it is NULL, then all attached databases are searched
4392** for the table using the same algorithm used by the database engine to
4393** resolve unqualified table references.
4394**
4395** ^The third and fourth parameters to this function are the table and column
4396** name of the desired column, respectively. Neither of these parameters
4397** may be NULL.
4398**
4399** ^Metadata is returned by writing to the memory locations passed as the 5th
4400** and subsequent parameters to this function. ^Any of these arguments may be
4401** NULL, in which case the corresponding element of metadata is omitted.
4402**
4403** ^(<blockquote>
4404** <table border="1">
4405** <tr><th> Parameter <th> Output<br>Type <th>  Description
4406**
4407** <tr><td> 5th <td> const char* <td> Data type
4408** <tr><td> 6th <td> const char* <td> Name of default collation sequence
4409** <tr><td> 7th <td> int         <td> True if column has a NOT NULL constraint
4410** <tr><td> 8th <td> int         <td> True if column is part of the PRIMARY KEY
4411** <tr><td> 9th <td> int         <td> True if column is [AUTOINCREMENT]
4412** </table>
4413** </blockquote>)^
4414**
4415** ^The memory pointed to by the character pointers returned for the
4416** declaration type and collation sequence is valid only until the next
4417** call to any SQLite API function.
4418**
4419** ^If the specified table is actually a view, an [error code] is returned.
4420**
4421** ^If the specified column is "rowid", "oid" or "_rowid_" and an
4422** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
4423** parameters are set for the explicitly declared column. ^(If there is no
4424** explicitly declared [INTEGER PRIMARY KEY] column, then the output
4425** parameters are set as follows:
4426**
4427** <pre>
4428**     data type: "INTEGER"
4429**     collation sequence: "BINARY"
4430**     not null: 0
4431**     primary key: 1
4432**     auto increment: 0
4433** </pre>)^
4434**
4435** ^(This function may load one or more schemas from database files. If an
4436** error occurs during this process, or if the requested table or column
4437** cannot be found, an [error code] is returned and an error message left
4438** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^
4439**
4440** ^This API is only available if the library was compiled with the
4441** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined.
4442*/
4443int sqlite3_table_column_metadata(
4444  sqlite3 *db,                /* Connection handle */
4445  const char *zDbName,        /* Database name or NULL */
4446  const char *zTableName,     /* Table name */
4447  const char *zColumnName,    /* Column name */
4448  char const **pzDataType,    /* OUTPUT: Declared data type */
4449  char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
4450  int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
4451  int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
4452  int *pAutoinc               /* OUTPUT: True if column is auto-increment */
4453);
4454
4455/*
4456** CAPI3REF: Load An Extension
4457**
4458** ^This interface loads an SQLite extension library from the named file.
4459**
4460** ^The sqlite3_load_extension() interface attempts to load an
4461** SQLite extension library contained in the file zFile.
4462**
4463** ^The entry point is zProc.
4464** ^zProc may be 0, in which case the name of the entry point
4465** defaults to "sqlite3_extension_init".
4466** ^The sqlite3_load_extension() interface returns
4467** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
4468** ^If an error occurs and pzErrMsg is not 0, then the
4469** [sqlite3_load_extension()] interface shall attempt to
4470** fill *pzErrMsg with error message text stored in memory
4471** obtained from [sqlite3_malloc()]. The calling function
4472** should free this memory by calling [sqlite3_free()].
4473**
4474** ^Extension loading must be enabled using
4475** [sqlite3_enable_load_extension()] prior to calling this API,
4476** otherwise an error will be returned.
4477**
4478** See also the [load_extension() SQL function].
4479*/
4480int sqlite3_load_extension(
4481  sqlite3 *db,          /* Load the extension into this database connection */
4482  const char *zFile,    /* Name of the shared library containing extension */
4483  const char *zProc,    /* Entry point.  Derived from zFile if 0 */
4484  char **pzErrMsg       /* Put error message here if not 0 */
4485);
4486
4487/*
4488** CAPI3REF: Enable Or Disable Extension Loading
4489**
4490** ^So as not to open security holes in older applications that are
4491** unprepared to deal with extension loading, and as a means of disabling
4492** extension loading while evaluating user-entered SQL, the following API
4493** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
4494**
4495** ^Extension loading is off by default. See ticket #1863.
4496** ^Call the sqlite3_enable_load_extension() routine with onoff==1
4497** to turn extension loading on and call it with onoff==0 to turn
4498** it back off again.
4499*/
4500int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
4501
4502/*
4503** CAPI3REF: Automatically Load Statically Linked Extensions
4504**
4505** ^This interface causes the xEntryPoint() function to be invoked for
4506** each new [database connection] that is created.  The idea here is that
4507** xEntryPoint() is the entry point for a statically linked SQLite extension
4508** that is to be automatically loaded into all new database connections.
4509**
4510** ^(Even though the function prototype shows that xEntryPoint() takes
4511** no arguments and returns void, SQLite invokes xEntryPoint() with three
4512** arguments and expects and integer result as if the signature of the
4513** entry point where as follows:
4514**
4515** <blockquote><pre>
4516** &nbsp;  int xEntryPoint(
4517** &nbsp;    sqlite3 *db,
4518** &nbsp;    const char **pzErrMsg,
4519** &nbsp;    const struct sqlite3_api_routines *pThunk
4520** &nbsp;  );
4521** </pre></blockquote>)^
4522**
4523** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
4524** point to an appropriate error message (obtained from [sqlite3_mprintf()])
4525** and return an appropriate [error code].  ^SQLite ensures that *pzErrMsg
4526** is NULL before calling the xEntryPoint().  ^SQLite will invoke
4527** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns.  ^If any
4528** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
4529** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
4530**
4531** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
4532** on the list of automatic extensions is a harmless no-op. ^No entry point
4533** will be called more than once for each database connection that is opened.
4534**
4535** See also: [sqlite3_reset_auto_extension()].
4536*/
4537int sqlite3_auto_extension(void (*xEntryPoint)(void));
4538
4539/*
4540** CAPI3REF: Reset Automatic Extension Loading
4541**
4542** ^This interface disables all automatic extensions previously
4543** registered using [sqlite3_auto_extension()].
4544*/
4545void sqlite3_reset_auto_extension(void);
4546
4547/*
4548** The interface to the virtual-table mechanism is currently considered
4549** to be experimental.  The interface might change in incompatible ways.
4550** If this is a problem for you, do not use the interface at this time.
4551**
4552** When the virtual-table mechanism stabilizes, we will declare the
4553** interface fixed, support it indefinitely, and remove this comment.
4554*/
4555
4556/*
4557** Structures used by the virtual table interface
4558*/
4559typedef struct sqlite3_vtab sqlite3_vtab;
4560typedef struct sqlite3_index_info sqlite3_index_info;
4561typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
4562typedef struct sqlite3_module sqlite3_module;
4563
4564/*
4565** CAPI3REF: Virtual Table Object
4566** KEYWORDS: sqlite3_module {virtual table module}
4567**
4568** This structure, sometimes called a "virtual table module",
4569** defines the implementation of a [virtual tables].
4570** This structure consists mostly of methods for the module.
4571**
4572** ^A virtual table module is created by filling in a persistent
4573** instance of this structure and passing a pointer to that instance
4574** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
4575** ^The registration remains valid until it is replaced by a different
4576** module or until the [database connection] closes.  The content
4577** of this structure must not change while it is registered with
4578** any database connection.
4579*/
4580struct sqlite3_module {
4581  int iVersion;
4582  int (*xCreate)(sqlite3*, void *pAux,
4583               int argc, const char *const*argv,
4584               sqlite3_vtab **ppVTab, char**);
4585  int (*xConnect)(sqlite3*, void *pAux,
4586               int argc, const char *const*argv,
4587               sqlite3_vtab **ppVTab, char**);
4588  int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
4589  int (*xDisconnect)(sqlite3_vtab *pVTab);
4590  int (*xDestroy)(sqlite3_vtab *pVTab);
4591  int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
4592  int (*xClose)(sqlite3_vtab_cursor*);
4593  int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
4594                int argc, sqlite3_value **argv);
4595  int (*xNext)(sqlite3_vtab_cursor*);
4596  int (*xEof)(sqlite3_vtab_cursor*);
4597  int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
4598  int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
4599  int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
4600  int (*xBegin)(sqlite3_vtab *pVTab);
4601  int (*xSync)(sqlite3_vtab *pVTab);
4602  int (*xCommit)(sqlite3_vtab *pVTab);
4603  int (*xRollback)(sqlite3_vtab *pVTab);
4604  int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
4605                       void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
4606                       void **ppArg);
4607  int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
4608};
4609
4610/*
4611** CAPI3REF: Virtual Table Indexing Information
4612** KEYWORDS: sqlite3_index_info
4613**
4614** The sqlite3_index_info structure and its substructures is used as part
4615** of the [virtual table] interface to
4616** pass information into and receive the reply from the [xBestIndex]
4617** method of a [virtual table module].  The fields under **Inputs** are the
4618** inputs to xBestIndex and are read-only.  xBestIndex inserts its
4619** results into the **Outputs** fields.
4620**
4621** ^(The aConstraint[] array records WHERE clause constraints of the form:
4622**
4623** <blockquote>column OP expr</blockquote>
4624**
4625** where OP is =, &lt;, &lt;=, &gt;, or &gt;=.)^  ^(The particular operator is
4626** stored in aConstraint[].op using one of the
4627** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
4628** ^(The index of the column is stored in
4629** aConstraint[].iColumn.)^  ^(aConstraint[].usable is TRUE if the
4630** expr on the right-hand side can be evaluated (and thus the constraint
4631** is usable) and false if it cannot.)^
4632**
4633** ^The optimizer automatically inverts terms of the form "expr OP column"
4634** and makes other simplifications to the WHERE clause in an attempt to
4635** get as many WHERE clause terms into the form shown above as possible.
4636** ^The aConstraint[] array only reports WHERE clause terms that are
4637** relevant to the particular virtual table being queried.
4638**
4639** ^Information about the ORDER BY clause is stored in aOrderBy[].
4640** ^Each term of aOrderBy records a column of the ORDER BY clause.
4641**
4642** The [xBestIndex] method must fill aConstraintUsage[] with information
4643** about what parameters to pass to xFilter.  ^If argvIndex>0 then
4644** the right-hand side of the corresponding aConstraint[] is evaluated
4645** and becomes the argvIndex-th entry in argv.  ^(If aConstraintUsage[].omit
4646** is true, then the constraint is assumed to be fully handled by the
4647** virtual table and is not checked again by SQLite.)^
4648**
4649** ^The idxNum and idxPtr values are recorded and passed into the
4650** [xFilter] method.
4651** ^[sqlite3_free()] is used to free idxPtr if and only if
4652** needToFreeIdxPtr is true.
4653**
4654** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
4655** the correct order to satisfy the ORDER BY clause so that no separate
4656** sorting step is required.
4657**
4658** ^The estimatedCost value is an estimate of the cost of doing the
4659** particular lookup.  A full scan of a table with N entries should have
4660** a cost of N.  A binary search of a table of N entries should have a
4661** cost of approximately log(N).
4662*/
4663struct sqlite3_index_info {
4664  /* Inputs */
4665  int nConstraint;           /* Number of entries in aConstraint */
4666  struct sqlite3_index_constraint {
4667     int iColumn;              /* Column on left-hand side of constraint */
4668     unsigned char op;         /* Constraint operator */
4669     unsigned char usable;     /* True if this constraint is usable */
4670     int iTermOffset;          /* Used internally - xBestIndex should ignore */
4671  } *aConstraint;            /* Table of WHERE clause constraints */
4672  int nOrderBy;              /* Number of terms in the ORDER BY clause */
4673  struct sqlite3_index_orderby {
4674     int iColumn;              /* Column number */
4675     unsigned char desc;       /* True for DESC.  False for ASC. */
4676  } *aOrderBy;               /* The ORDER BY clause */
4677  /* Outputs */
4678  struct sqlite3_index_constraint_usage {
4679    int argvIndex;           /* if >0, constraint is part of argv to xFilter */
4680    unsigned char omit;      /* Do not code a test for this constraint */
4681  } *aConstraintUsage;
4682  int idxNum;                /* Number used to identify the index */
4683  char *idxStr;              /* String, possibly obtained from sqlite3_malloc */
4684  int needToFreeIdxStr;      /* Free idxStr using sqlite3_free() if true */
4685  int orderByConsumed;       /* True if output is already ordered */
4686  double estimatedCost;      /* Estimated cost of using this index */
4687};
4688
4689/* Begin preload-cache.patch for Chromium */
4690/*
4691** Preload the databases into the pager cache, up to the maximum size of the
4692** pager cache.
4693**
4694** For a database to be loaded successfully, the pager must be active. That is,
4695** there must be an open statement on that database. See sqlite3pager_loadall
4696**
4697** There might be many databases attached to the given connection. We iterate
4698** them all and try to load them. If none are loadable successfully, we return
4699** an error. Otherwise, we return OK.
4700*/
4701int sqlite3_preload(sqlite3 *db);
4702/* End preload-cache.patch for Chromium */
4703
4704/*
4705** CAPI3REF: Virtual Table Constraint Operator Codes
4706**
4707** These macros defined the allowed values for the
4708** [sqlite3_index_info].aConstraint[].op field.  Each value represents
4709** an operator that is part of a constraint term in the wHERE clause of
4710** a query that uses a [virtual table].
4711*/
4712#define SQLITE_INDEX_CONSTRAINT_EQ    2
4713#define SQLITE_INDEX_CONSTRAINT_GT    4
4714#define SQLITE_INDEX_CONSTRAINT_LE    8
4715#define SQLITE_INDEX_CONSTRAINT_LT    16
4716#define SQLITE_INDEX_CONSTRAINT_GE    32
4717#define SQLITE_INDEX_CONSTRAINT_MATCH 64
4718
4719/*
4720** CAPI3REF: Register A Virtual Table Implementation
4721**
4722** ^These routines are used to register a new [virtual table module] name.
4723** ^Module names must be registered before
4724** creating a new [virtual table] using the module and before using a
4725** preexisting [virtual table] for the module.
4726**
4727** ^The module name is registered on the [database connection] specified
4728** by the first parameter.  ^The name of the module is given by the
4729** second parameter.  ^The third parameter is a pointer to
4730** the implementation of the [virtual table module].   ^The fourth
4731** parameter is an arbitrary client data pointer that is passed through
4732** into the [xCreate] and [xConnect] methods of the virtual table module
4733** when a new virtual table is be being created or reinitialized.
4734**
4735** ^The sqlite3_create_module_v2() interface has a fifth parameter which
4736** is a pointer to a destructor for the pClientData.  ^SQLite will
4737** invoke the destructor function (if it is not NULL) when SQLite
4738** no longer needs the pClientData pointer.  ^The destructor will also
4739** be invoked if the call to sqlite3_create_module_v2() fails.
4740** ^The sqlite3_create_module()
4741** interface is equivalent to sqlite3_create_module_v2() with a NULL
4742** destructor.
4743*/
4744int sqlite3_create_module(
4745  sqlite3 *db,               /* SQLite connection to register module with */
4746  const char *zName,         /* Name of the module */
4747  const sqlite3_module *p,   /* Methods for the module */
4748  void *pClientData          /* Client data for xCreate/xConnect */
4749);
4750int sqlite3_create_module_v2(
4751  sqlite3 *db,               /* SQLite connection to register module with */
4752  const char *zName,         /* Name of the module */
4753  const sqlite3_module *p,   /* Methods for the module */
4754  void *pClientData,         /* Client data for xCreate/xConnect */
4755  void(*xDestroy)(void*)     /* Module destructor function */
4756);
4757
4758/*
4759** CAPI3REF: Virtual Table Instance Object
4760** KEYWORDS: sqlite3_vtab
4761**
4762** Every [virtual table module] implementation uses a subclass
4763** of this object to describe a particular instance
4764** of the [virtual table].  Each subclass will
4765** be tailored to the specific needs of the module implementation.
4766** The purpose of this superclass is to define certain fields that are
4767** common to all module implementations.
4768**
4769** ^Virtual tables methods can set an error message by assigning a
4770** string obtained from [sqlite3_mprintf()] to zErrMsg.  The method should
4771** take care that any prior string is freed by a call to [sqlite3_free()]
4772** prior to assigning a new string to zErrMsg.  ^After the error message
4773** is delivered up to the client application, the string will be automatically
4774** freed by sqlite3_free() and the zErrMsg field will be zeroed.
4775*/
4776struct sqlite3_vtab {
4777  const sqlite3_module *pModule;  /* The module for this virtual table */
4778  int nRef;                       /* NO LONGER USED */
4779  char *zErrMsg;                  /* Error message from sqlite3_mprintf() */
4780  /* Virtual table implementations will typically add additional fields */
4781};
4782
4783/*
4784** CAPI3REF: Virtual Table Cursor Object
4785** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
4786**
4787** Every [virtual table module] implementation uses a subclass of the
4788** following structure to describe cursors that point into the
4789** [virtual table] and are used
4790** to loop through the virtual table.  Cursors are created using the
4791** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
4792** by the [sqlite3_module.xClose | xClose] method.  Cursors are used
4793** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
4794** of the module.  Each module implementation will define
4795** the content of a cursor structure to suit its own needs.
4796**
4797** This superclass exists in order to define fields of the cursor that
4798** are common to all implementations.
4799*/
4800struct sqlite3_vtab_cursor {
4801  sqlite3_vtab *pVtab;      /* Virtual table of this cursor */
4802  /* Virtual table implementations will typically add additional fields */
4803};
4804
4805/*
4806** CAPI3REF: Declare The Schema Of A Virtual Table
4807**
4808** ^The [xCreate] and [xConnect] methods of a
4809** [virtual table module] call this interface
4810** to declare the format (the names and datatypes of the columns) of
4811** the virtual tables they implement.
4812*/
4813int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
4814
4815/*
4816** CAPI3REF: Overload A Function For A Virtual Table
4817**
4818** ^(Virtual tables can provide alternative implementations of functions
4819** using the [xFindFunction] method of the [virtual table module].
4820** But global versions of those functions
4821** must exist in order to be overloaded.)^
4822**
4823** ^(This API makes sure a global version of a function with a particular
4824** name and number of parameters exists.  If no such function exists
4825** before this API is called, a new function is created.)^  ^The implementation
4826** of the new function always causes an exception to be thrown.  So
4827** the new function is not good for anything by itself.  Its only
4828** purpose is to be a placeholder function that can be overloaded
4829** by a [virtual table].
4830*/
4831int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
4832
4833/*
4834** The interface to the virtual-table mechanism defined above (back up
4835** to a comment remarkably similar to this one) is currently considered
4836** to be experimental.  The interface might change in incompatible ways.
4837** If this is a problem for you, do not use the interface at this time.
4838**
4839** When the virtual-table mechanism stabilizes, we will declare the
4840** interface fixed, support it indefinitely, and remove this comment.
4841*/
4842
4843/*
4844** CAPI3REF: A Handle To An Open BLOB
4845** KEYWORDS: {BLOB handle} {BLOB handles}
4846**
4847** An instance of this object represents an open BLOB on which
4848** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
4849** ^Objects of this type are created by [sqlite3_blob_open()]
4850** and destroyed by [sqlite3_blob_close()].
4851** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
4852** can be used to read or write small subsections of the BLOB.
4853** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
4854*/
4855typedef struct sqlite3_blob sqlite3_blob;
4856
4857/*
4858** CAPI3REF: Open A BLOB For Incremental I/O
4859**
4860** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
4861** in row iRow, column zColumn, table zTable in database zDb;
4862** in other words, the same BLOB that would be selected by:
4863**
4864** <pre>
4865**     SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
4866** </pre>)^
4867**
4868** ^If the flags parameter is non-zero, then the BLOB is opened for read
4869** and write access. ^If it is zero, the BLOB is opened for read access.
4870** ^It is not possible to open a column that is part of an index or primary
4871** key for writing. ^If [foreign key constraints] are enabled, it is
4872** not possible to open a column that is part of a [child key] for writing.
4873**
4874** ^Note that the database name is not the filename that contains
4875** the database but rather the symbolic name of the database that
4876** appears after the AS keyword when the database is connected using [ATTACH].
4877** ^For the main database file, the database name is "main".
4878** ^For TEMP tables, the database name is "temp".
4879**
4880** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written
4881** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set
4882** to be a null pointer.)^
4883** ^This function sets the [database connection] error code and message
4884** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related
4885** functions. ^Note that the *ppBlob variable is always initialized in a
4886** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob
4887** regardless of the success or failure of this routine.
4888**
4889** ^(If the row that a BLOB handle points to is modified by an
4890** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
4891** then the BLOB handle is marked as "expired".
4892** This is true if any column of the row is changed, even a column
4893** other than the one the BLOB handle is open on.)^
4894** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
4895** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
4896** ^(Changes written into a BLOB prior to the BLOB expiring are not
4897** rolled back by the expiration of the BLOB.  Such changes will eventually
4898** commit if the transaction continues to completion.)^
4899**
4900** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
4901** the opened blob.  ^The size of a blob may not be changed by this
4902** interface.  Use the [UPDATE] SQL command to change the size of a
4903** blob.
4904**
4905** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
4906** and the built-in [zeroblob] SQL function can be used, if desired,
4907** to create an empty, zero-filled blob in which to read or write using
4908** this interface.
4909**
4910** To avoid a resource leak, every open [BLOB handle] should eventually
4911** be released by a call to [sqlite3_blob_close()].
4912*/
4913int sqlite3_blob_open(
4914  sqlite3*,
4915  const char *zDb,
4916  const char *zTable,
4917  const char *zColumn,
4918  sqlite3_int64 iRow,
4919  int flags,
4920  sqlite3_blob **ppBlob
4921);
4922
4923/*
4924** CAPI3REF: Move a BLOB Handle to a New Row
4925**
4926** ^This function is used to move an existing blob handle so that it points
4927** to a different row of the same database table. ^The new row is identified
4928** by the rowid value passed as the second argument. Only the row can be
4929** changed. ^The database, table and column on which the blob handle is open
4930** remain the same. Moving an existing blob handle to a new row can be
4931** faster than closing the existing handle and opening a new one.
4932**
4933** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
4934** it must exist and there must be either a blob or text value stored in
4935** the nominated column.)^ ^If the new row is not present in the table, or if
4936** it does not contain a blob or text value, or if another error occurs, an
4937** SQLite error code is returned and the blob handle is considered aborted.
4938** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
4939** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
4940** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
4941** always returns zero.
4942**
4943** ^This function sets the database handle error code and message.
4944*/
4945SQLITE_EXPERIMENTAL int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
4946
4947/*
4948** CAPI3REF: Close A BLOB Handle
4949**
4950** ^Closes an open [BLOB handle].
4951**
4952** ^Closing a BLOB shall cause the current transaction to commit
4953** if there are no other BLOBs, no pending prepared statements, and the
4954** database connection is in [autocommit mode].
4955** ^If any writes were made to the BLOB, they might be held in cache
4956** until the close operation if they will fit.
4957**
4958** ^(Closing the BLOB often forces the changes
4959** out to disk and so if any I/O errors occur, they will likely occur
4960** at the time when the BLOB is closed.  Any errors that occur during
4961** closing are reported as a non-zero return value.)^
4962**
4963** ^(The BLOB is closed unconditionally.  Even if this routine returns
4964** an error code, the BLOB is still closed.)^
4965**
4966** ^Calling this routine with a null pointer (such as would be returned
4967** by a failed call to [sqlite3_blob_open()]) is a harmless no-op.
4968*/
4969int sqlite3_blob_close(sqlite3_blob *);
4970
4971/*
4972** CAPI3REF: Return The Size Of An Open BLOB
4973**
4974** ^Returns the size in bytes of the BLOB accessible via the
4975** successfully opened [BLOB handle] in its only argument.  ^The
4976** incremental blob I/O routines can only read or overwriting existing
4977** blob content; they cannot change the size of a blob.
4978**
4979** This routine only works on a [BLOB handle] which has been created
4980** by a prior successful call to [sqlite3_blob_open()] and which has not
4981** been closed by [sqlite3_blob_close()].  Passing any other pointer in
4982** to this routine results in undefined and probably undesirable behavior.
4983*/
4984int sqlite3_blob_bytes(sqlite3_blob *);
4985
4986/*
4987** CAPI3REF: Read Data From A BLOB Incrementally
4988**
4989** ^(This function is used to read data from an open [BLOB handle] into a
4990** caller-supplied buffer. N bytes of data are copied into buffer Z
4991** from the open BLOB, starting at offset iOffset.)^
4992**
4993** ^If offset iOffset is less than N bytes from the end of the BLOB,
4994** [SQLITE_ERROR] is returned and no data is read.  ^If N or iOffset is
4995** less than zero, [SQLITE_ERROR] is returned and no data is read.
4996** ^The size of the blob (and hence the maximum value of N+iOffset)
4997** can be determined using the [sqlite3_blob_bytes()] interface.
4998**
4999** ^An attempt to read from an expired [BLOB handle] fails with an
5000** error code of [SQLITE_ABORT].
5001**
5002** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
5003** Otherwise, an [error code] or an [extended error code] is returned.)^
5004**
5005** This routine only works on a [BLOB handle] which has been created
5006** by a prior successful call to [sqlite3_blob_open()] and which has not
5007** been closed by [sqlite3_blob_close()].  Passing any other pointer in
5008** to this routine results in undefined and probably undesirable behavior.
5009**
5010** See also: [sqlite3_blob_write()].
5011*/
5012int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
5013
5014/*
5015** CAPI3REF: Write Data Into A BLOB Incrementally
5016**
5017** ^This function is used to write data into an open [BLOB handle] from a
5018** caller-supplied buffer. ^N bytes of data are copied from the buffer Z
5019** into the open BLOB, starting at offset iOffset.
5020**
5021** ^If the [BLOB handle] passed as the first argument was not opened for
5022** writing (the flags parameter to [sqlite3_blob_open()] was zero),
5023** this function returns [SQLITE_READONLY].
5024**
5025** ^This function may only modify the contents of the BLOB; it is
5026** not possible to increase the size of a BLOB using this API.
5027** ^If offset iOffset is less than N bytes from the end of the BLOB,
5028** [SQLITE_ERROR] is returned and no data is written.  ^If N is
5029** less than zero [SQLITE_ERROR] is returned and no data is written.
5030** The size of the BLOB (and hence the maximum value of N+iOffset)
5031** can be determined using the [sqlite3_blob_bytes()] interface.
5032**
5033** ^An attempt to write to an expired [BLOB handle] fails with an
5034** error code of [SQLITE_ABORT].  ^Writes to the BLOB that occurred
5035** before the [BLOB handle] expired are not rolled back by the
5036** expiration of the handle, though of course those changes might
5037** have been overwritten by the statement that expired the BLOB handle
5038** or by other independent statements.
5039**
5040** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
5041** Otherwise, an  [error code] or an [extended error code] is returned.)^
5042**
5043** This routine only works on a [BLOB handle] which has been created
5044** by a prior successful call to [sqlite3_blob_open()] and which has not
5045** been closed by [sqlite3_blob_close()].  Passing any other pointer in
5046** to this routine results in undefined and probably undesirable behavior.
5047**
5048** See also: [sqlite3_blob_read()].
5049*/
5050int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
5051
5052/*
5053** CAPI3REF: Virtual File System Objects
5054**
5055** A virtual filesystem (VFS) is an [sqlite3_vfs] object
5056** that SQLite uses to interact
5057** with the underlying operating system.  Most SQLite builds come with a
5058** single default VFS that is appropriate for the host computer.
5059** New VFSes can be registered and existing VFSes can be unregistered.
5060** The following interfaces are provided.
5061**
5062** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
5063** ^Names are case sensitive.
5064** ^Names are zero-terminated UTF-8 strings.
5065** ^If there is no match, a NULL pointer is returned.
5066** ^If zVfsName is NULL then the default VFS is returned.
5067**
5068** ^New VFSes are registered with sqlite3_vfs_register().
5069** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
5070** ^The same VFS can be registered multiple times without injury.
5071** ^To make an existing VFS into the default VFS, register it again
5072** with the makeDflt flag set.  If two different VFSes with the
5073** same name are registered, the behavior is undefined.  If a
5074** VFS is registered with a name that is NULL or an empty string,
5075** then the behavior is undefined.
5076**
5077** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
5078** ^(If the default VFS is unregistered, another VFS is chosen as
5079** the default.  The choice for the new VFS is arbitrary.)^
5080*/
5081sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
5082int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
5083int sqlite3_vfs_unregister(sqlite3_vfs*);
5084
5085/*
5086** CAPI3REF: Mutexes
5087**
5088** The SQLite core uses these routines for thread
5089** synchronization. Though they are intended for internal
5090** use by SQLite, code that links against SQLite is
5091** permitted to use any of these routines.
5092**
5093** The SQLite source code contains multiple implementations
5094** of these mutex routines.  An appropriate implementation
5095** is selected automatically at compile-time.  ^(The following
5096** implementations are available in the SQLite core:
5097**
5098** <ul>
5099** <li>   SQLITE_MUTEX_OS2
5100** <li>   SQLITE_MUTEX_PTHREAD
5101** <li>   SQLITE_MUTEX_W32
5102** <li>   SQLITE_MUTEX_NOOP
5103** </ul>)^
5104**
5105** ^The SQLITE_MUTEX_NOOP implementation is a set of routines
5106** that does no real locking and is appropriate for use in
5107** a single-threaded application.  ^The SQLITE_MUTEX_OS2,
5108** SQLITE_MUTEX_PTHREAD, and SQLITE_MUTEX_W32 implementations
5109** are appropriate for use on OS/2, Unix, and Windows.
5110**
5111** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
5112** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
5113** implementation is included with the library. In this case the
5114** application must supply a custom mutex implementation using the
5115** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
5116** before calling sqlite3_initialize() or any other public sqlite3_
5117** function that calls sqlite3_initialize().)^
5118**
5119** ^The sqlite3_mutex_alloc() routine allocates a new
5120** mutex and returns a pointer to it. ^If it returns NULL
5121** that means that a mutex could not be allocated.  ^SQLite
5122** will unwind its stack and return an error.  ^(The argument
5123** to sqlite3_mutex_alloc() is one of these integer constants:
5124**
5125** <ul>
5126** <li>  SQLITE_MUTEX_FAST
5127** <li>  SQLITE_MUTEX_RECURSIVE
5128** <li>  SQLITE_MUTEX_STATIC_MASTER
5129** <li>  SQLITE_MUTEX_STATIC_MEM
5130** <li>  SQLITE_MUTEX_STATIC_MEM2
5131** <li>  SQLITE_MUTEX_STATIC_PRNG
5132** <li>  SQLITE_MUTEX_STATIC_LRU
5133** <li>  SQLITE_MUTEX_STATIC_LRU2
5134** </ul>)^
5135**
5136** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
5137** cause sqlite3_mutex_alloc() to create
5138** a new mutex.  ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
5139** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
5140** The mutex implementation does not need to make a distinction
5141** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
5142** not want to.  ^SQLite will only request a recursive mutex in
5143** cases where it really needs one.  ^If a faster non-recursive mutex
5144** implementation is available on the host platform, the mutex subsystem
5145** might return such a mutex in response to SQLITE_MUTEX_FAST.
5146**
5147** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
5148** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
5149** a pointer to a static preexisting mutex.  ^Six static mutexes are
5150** used by the current version of SQLite.  Future versions of SQLite
5151** may add additional static mutexes.  Static mutexes are for internal
5152** use by SQLite only.  Applications that use SQLite mutexes should
5153** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
5154** SQLITE_MUTEX_RECURSIVE.
5155**
5156** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
5157** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
5158** returns a different mutex on every call.  ^But for the static
5159** mutex types, the same mutex is returned on every call that has
5160** the same type number.
5161**
5162** ^The sqlite3_mutex_free() routine deallocates a previously
5163** allocated dynamic mutex.  ^SQLite is careful to deallocate every
5164** dynamic mutex that it allocates.  The dynamic mutexes must not be in
5165** use when they are deallocated.  Attempting to deallocate a static
5166** mutex results in undefined behavior.  ^SQLite never deallocates
5167** a static mutex.
5168**
5169** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
5170** to enter a mutex.  ^If another thread is already within the mutex,
5171** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
5172** SQLITE_BUSY.  ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
5173** upon successful entry.  ^(Mutexes created using
5174** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
5175** In such cases the,
5176** mutex must be exited an equal number of times before another thread
5177** can enter.)^  ^(If the same thread tries to enter any other
5178** kind of mutex more than once, the behavior is undefined.
5179** SQLite will never exhibit
5180** such behavior in its own use of mutexes.)^
5181**
5182** ^(Some systems (for example, Windows 95) do not support the operation
5183** implemented by sqlite3_mutex_try().  On those systems, sqlite3_mutex_try()
5184** will always return SQLITE_BUSY.  The SQLite core only ever uses
5185** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^
5186**
5187** ^The sqlite3_mutex_leave() routine exits a mutex that was
5188** previously entered by the same thread.   ^(The behavior
5189** is undefined if the mutex is not currently entered by the
5190** calling thread or is not currently allocated.  SQLite will
5191** never do either.)^
5192**
5193** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
5194** sqlite3_mutex_leave() is a NULL pointer, then all three routines
5195** behave as no-ops.
5196**
5197** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
5198*/
5199sqlite3_mutex *sqlite3_mutex_alloc(int);
5200void sqlite3_mutex_free(sqlite3_mutex*);
5201void sqlite3_mutex_enter(sqlite3_mutex*);
5202int sqlite3_mutex_try(sqlite3_mutex*);
5203void sqlite3_mutex_leave(sqlite3_mutex*);
5204
5205/*
5206** CAPI3REF: Mutex Methods Object
5207**
5208** An instance of this structure defines the low-level routines
5209** used to allocate and use mutexes.
5210**
5211** Usually, the default mutex implementations provided by SQLite are
5212** sufficient, however the user has the option of substituting a custom
5213** implementation for specialized deployments or systems for which SQLite
5214** does not provide a suitable implementation. In this case, the user
5215** creates and populates an instance of this structure to pass
5216** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
5217** Additionally, an instance of this structure can be used as an
5218** output variable when querying the system for the current mutex
5219** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
5220**
5221** ^The xMutexInit method defined by this structure is invoked as
5222** part of system initialization by the sqlite3_initialize() function.
5223** ^The xMutexInit routine is called by SQLite exactly once for each
5224** effective call to [sqlite3_initialize()].
5225**
5226** ^The xMutexEnd method defined by this structure is invoked as
5227** part of system shutdown by the sqlite3_shutdown() function. The
5228** implementation of this method is expected to release all outstanding
5229** resources obtained by the mutex methods implementation, especially
5230** those obtained by the xMutexInit method.  ^The xMutexEnd()
5231** interface is invoked exactly once for each call to [sqlite3_shutdown()].
5232**
5233** ^(The remaining seven methods defined by this structure (xMutexAlloc,
5234** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
5235** xMutexNotheld) implement the following interfaces (respectively):
5236**
5237** <ul>
5238**   <li>  [sqlite3_mutex_alloc()] </li>
5239**   <li>  [sqlite3_mutex_free()] </li>
5240**   <li>  [sqlite3_mutex_enter()] </li>
5241**   <li>  [sqlite3_mutex_try()] </li>
5242**   <li>  [sqlite3_mutex_leave()] </li>
5243**   <li>  [sqlite3_mutex_held()] </li>
5244**   <li>  [sqlite3_mutex_notheld()] </li>
5245** </ul>)^
5246**
5247** The only difference is that the public sqlite3_XXX functions enumerated
5248** above silently ignore any invocations that pass a NULL pointer instead
5249** of a valid mutex handle. The implementations of the methods defined
5250** by this structure are not required to handle this case, the results
5251** of passing a NULL pointer instead of a valid mutex handle are undefined
5252** (i.e. it is acceptable to provide an implementation that segfaults if
5253** it is passed a NULL pointer).
5254**
5255** The xMutexInit() method must be threadsafe.  ^It must be harmless to
5256** invoke xMutexInit() multiple times within the same process and without
5257** intervening calls to xMutexEnd().  Second and subsequent calls to
5258** xMutexInit() must be no-ops.
5259**
5260** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
5261** and its associates).  ^Similarly, xMutexAlloc() must not use SQLite memory
5262** allocation for a static mutex.  ^However xMutexAlloc() may use SQLite
5263** memory allocation for a fast or recursive mutex.
5264**
5265** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
5266** called, but only if the prior call to xMutexInit returned SQLITE_OK.
5267** If xMutexInit fails in any way, it is expected to clean up after itself
5268** prior to returning.
5269*/
5270typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
5271struct sqlite3_mutex_methods {
5272  int (*xMutexInit)(void);
5273  int (*xMutexEnd)(void);
5274  sqlite3_mutex *(*xMutexAlloc)(int);
5275  void (*xMutexFree)(sqlite3_mutex *);
5276  void (*xMutexEnter)(sqlite3_mutex *);
5277  int (*xMutexTry)(sqlite3_mutex *);
5278  void (*xMutexLeave)(sqlite3_mutex *);
5279  int (*xMutexHeld)(sqlite3_mutex *);
5280  int (*xMutexNotheld)(sqlite3_mutex *);
5281};
5282
5283/*
5284** CAPI3REF: Mutex Verification Routines
5285**
5286** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
5287** are intended for use inside assert() statements.  ^The SQLite core
5288** never uses these routines except inside an assert() and applications
5289** are advised to follow the lead of the core.  ^The SQLite core only
5290** provides implementations for these routines when it is compiled
5291** with the SQLITE_DEBUG flag.  ^External mutex implementations
5292** are only required to provide these routines if SQLITE_DEBUG is
5293** defined and if NDEBUG is not defined.
5294**
5295** ^These routines should return true if the mutex in their argument
5296** is held or not held, respectively, by the calling thread.
5297**
5298** ^The implementation is not required to provided versions of these
5299** routines that actually work. If the implementation does not provide working
5300** versions of these routines, it should at least provide stubs that always
5301** return true so that one does not get spurious assertion failures.
5302**
5303** ^If the argument to sqlite3_mutex_held() is a NULL pointer then
5304** the routine should return 1.   This seems counter-intuitive since
5305** clearly the mutex cannot be held if it does not exist.  But the
5306** the reason the mutex does not exist is because the build is not
5307** using mutexes.  And we do not want the assert() containing the
5308** call to sqlite3_mutex_held() to fail, so a non-zero return is
5309** the appropriate thing to do.  ^The sqlite3_mutex_notheld()
5310** interface should also return 1 when given a NULL pointer.
5311*/
5312#ifndef NDEBUG
5313int sqlite3_mutex_held(sqlite3_mutex*);
5314int sqlite3_mutex_notheld(sqlite3_mutex*);
5315#endif
5316
5317/*
5318** CAPI3REF: Mutex Types
5319**
5320** The [sqlite3_mutex_alloc()] interface takes a single argument
5321** which is one of these integer constants.
5322**
5323** The set of static mutexes may change from one SQLite release to the
5324** next.  Applications that override the built-in mutex logic must be
5325** prepared to accommodate additional static mutexes.
5326*/
5327#define SQLITE_MUTEX_FAST             0
5328#define SQLITE_MUTEX_RECURSIVE        1
5329#define SQLITE_MUTEX_STATIC_MASTER    2
5330#define SQLITE_MUTEX_STATIC_MEM       3  /* sqlite3_malloc() */
5331#define SQLITE_MUTEX_STATIC_MEM2      4  /* NOT USED */
5332#define SQLITE_MUTEX_STATIC_OPEN      4  /* sqlite3BtreeOpen() */
5333#define SQLITE_MUTEX_STATIC_PRNG      5  /* sqlite3_random() */
5334#define SQLITE_MUTEX_STATIC_LRU       6  /* lru page list */
5335#define SQLITE_MUTEX_STATIC_LRU2      7  /* NOT USED */
5336#define SQLITE_MUTEX_STATIC_PMEM      7  /* sqlite3PageMalloc() */
5337
5338/*
5339** CAPI3REF: Retrieve the mutex for a database connection
5340**
5341** ^This interface returns a pointer the [sqlite3_mutex] object that
5342** serializes access to the [database connection] given in the argument
5343** when the [threading mode] is Serialized.
5344** ^If the [threading mode] is Single-thread or Multi-thread then this
5345** routine returns a NULL pointer.
5346*/
5347sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
5348
5349/*
5350** CAPI3REF: Low-Level Control Of Database Files
5351**
5352** ^The [sqlite3_file_control()] interface makes a direct call to the
5353** xFileControl method for the [sqlite3_io_methods] object associated
5354** with a particular database identified by the second argument. ^The
5355** name of the database is "main" for the main database or "temp" for the
5356** TEMP database, or the name that appears after the AS keyword for
5357** databases that are added using the [ATTACH] SQL command.
5358** ^A NULL pointer can be used in place of "main" to refer to the
5359** main database file.
5360** ^The third and fourth parameters to this routine
5361** are passed directly through to the second and third parameters of
5362** the xFileControl method.  ^The return value of the xFileControl
5363** method becomes the return value of this routine.
5364**
5365** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes
5366** a pointer to the underlying [sqlite3_file] object to be written into
5367** the space pointed to by the 4th parameter.  ^The SQLITE_FCNTL_FILE_POINTER
5368** case is a short-circuit path which does not actually invoke the
5369** underlying sqlite3_io_methods.xFileControl method.
5370**
5371** ^If the second parameter (zDbName) does not match the name of any
5372** open database file, then SQLITE_ERROR is returned.  ^This error
5373** code is not remembered and will not be recalled by [sqlite3_errcode()]
5374** or [sqlite3_errmsg()].  The underlying xFileControl method might
5375** also return SQLITE_ERROR.  There is no way to distinguish between
5376** an incorrect zDbName and an SQLITE_ERROR return from the underlying
5377** xFileControl method.
5378**
5379** See also: [SQLITE_FCNTL_LOCKSTATE]
5380*/
5381int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
5382
5383/*
5384** CAPI3REF: Testing Interface
5385**
5386** ^The sqlite3_test_control() interface is used to read out internal
5387** state of SQLite and to inject faults into SQLite for testing
5388** purposes.  ^The first parameter is an operation code that determines
5389** the number, meaning, and operation of all subsequent parameters.
5390**
5391** This interface is not for use by applications.  It exists solely
5392** for verifying the correct operation of the SQLite library.  Depending
5393** on how the SQLite library is compiled, this interface might not exist.
5394**
5395** The details of the operation codes, their meanings, the parameters
5396** they take, and what they do are all subject to change without notice.
5397** Unlike most of the SQLite API, this function is not guaranteed to
5398** operate consistently from one release to the next.
5399*/
5400int sqlite3_test_control(int op, ...);
5401
5402/*
5403** CAPI3REF: Testing Interface Operation Codes
5404**
5405** These constants are the valid operation code parameters used
5406** as the first argument to [sqlite3_test_control()].
5407**
5408** These parameters and their meanings are subject to change
5409** without notice.  These values are for testing purposes only.
5410** Applications should not use any of these parameters or the
5411** [sqlite3_test_control()] interface.
5412*/
5413#define SQLITE_TESTCTRL_FIRST                    5
5414#define SQLITE_TESTCTRL_PRNG_SAVE                5
5415#define SQLITE_TESTCTRL_PRNG_RESTORE             6
5416#define SQLITE_TESTCTRL_PRNG_RESET               7
5417#define SQLITE_TESTCTRL_BITVEC_TEST              8
5418#define SQLITE_TESTCTRL_FAULT_INSTALL            9
5419#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS     10
5420#define SQLITE_TESTCTRL_PENDING_BYTE            11
5421#define SQLITE_TESTCTRL_ASSERT                  12
5422#define SQLITE_TESTCTRL_ALWAYS                  13
5423#define SQLITE_TESTCTRL_RESERVE                 14
5424#define SQLITE_TESTCTRL_OPTIMIZATIONS           15
5425#define SQLITE_TESTCTRL_ISKEYWORD               16
5426#define SQLITE_TESTCTRL_PGHDRSZ                 17
5427#define SQLITE_TESTCTRL_SCRATCHMALLOC           18
5428#define SQLITE_TESTCTRL_LAST                    18
5429
5430/*
5431** CAPI3REF: SQLite Runtime Status
5432**
5433** ^This interface is used to retrieve runtime status information
5434** about the performance of SQLite, and optionally to reset various
5435** highwater marks.  ^The first argument is an integer code for
5436** the specific parameter to measure.  ^(Recognized integer codes
5437** are of the form [SQLITE_STATUS_MEMORY_USED | SQLITE_STATUS_...].)^
5438** ^The current value of the parameter is returned into *pCurrent.
5439** ^The highest recorded value is returned in *pHighwater.  ^If the
5440** resetFlag is true, then the highest record value is reset after
5441** *pHighwater is written.  ^(Some parameters do not record the highest
5442** value.  For those parameters
5443** nothing is written into *pHighwater and the resetFlag is ignored.)^
5444** ^(Other parameters record only the highwater mark and not the current
5445** value.  For these latter parameters nothing is written into *pCurrent.)^
5446**
5447** ^The sqlite3_status() routine returns SQLITE_OK on success and a
5448** non-zero [error code] on failure.
5449**
5450** This routine is threadsafe but is not atomic.  This routine can be
5451** called while other threads are running the same or different SQLite
5452** interfaces.  However the values returned in *pCurrent and
5453** *pHighwater reflect the status of SQLite at different points in time
5454** and it is possible that another thread might change the parameter
5455** in between the times when *pCurrent and *pHighwater are written.
5456**
5457** See also: [sqlite3_db_status()]
5458*/
5459int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
5460
5461
5462/*
5463** CAPI3REF: Status Parameters
5464**
5465** These integer constants designate various run-time status parameters
5466** that can be returned by [sqlite3_status()].
5467**
5468** <dl>
5469** ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
5470** <dd>This parameter is the current amount of memory checked out
5471** using [sqlite3_malloc()], either directly or indirectly.  The
5472** figure includes calls made to [sqlite3_malloc()] by the application
5473** and internal memory usage by the SQLite library.  Scratch memory
5474** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache
5475** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
5476** this parameter.  The amount returned is the sum of the allocation
5477** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
5478**
5479** ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
5480** <dd>This parameter records the largest memory allocation request
5481** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
5482** internal equivalents).  Only the value returned in the
5483** *pHighwater parameter to [sqlite3_status()] is of interest.
5484** The value written into the *pCurrent parameter is undefined.</dd>)^
5485**
5486** ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
5487** <dd>This parameter records the number of separate memory allocations
5488** currently checked out.</dd>)^
5489**
5490** ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
5491** <dd>This parameter returns the number of pages used out of the
5492** [pagecache memory allocator] that was configured using
5493** [SQLITE_CONFIG_PAGECACHE].  The
5494** value returned is in pages, not in bytes.</dd>)^
5495**
5496** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
5497** <dd>This parameter returns the number of bytes of page cache
5498** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
5499** buffer and where forced to overflow to [sqlite3_malloc()].  The
5500** returned value includes allocations that overflowed because they
5501** where too large (they were larger than the "sz" parameter to
5502** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
5503** no space was left in the page cache.</dd>)^
5504**
5505** ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
5506** <dd>This parameter records the largest memory allocation request
5507** handed to [pagecache memory allocator].  Only the value returned in the
5508** *pHighwater parameter to [sqlite3_status()] is of interest.
5509** The value written into the *pCurrent parameter is undefined.</dd>)^
5510**
5511** ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt>
5512** <dd>This parameter returns the number of allocations used out of the
5513** [scratch memory allocator] configured using
5514** [SQLITE_CONFIG_SCRATCH].  The value returned is in allocations, not
5515** in bytes.  Since a single thread may only have one scratch allocation
5516** outstanding at time, this parameter also reports the number of threads
5517** using scratch memory at the same time.</dd>)^
5518**
5519** ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
5520** <dd>This parameter returns the number of bytes of scratch memory
5521** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH]
5522** buffer and where forced to overflow to [sqlite3_malloc()].  The values
5523** returned include overflows because the requested allocation was too
5524** larger (that is, because the requested allocation was larger than the
5525** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer
5526** slots were available.
5527** </dd>)^
5528**
5529** ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
5530** <dd>This parameter records the largest memory allocation request
5531** handed to [scratch memory allocator].  Only the value returned in the
5532** *pHighwater parameter to [sqlite3_status()] is of interest.
5533** The value written into the *pCurrent parameter is undefined.</dd>)^
5534**
5535** ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
5536** <dd>This parameter records the deepest parser stack.  It is only
5537** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
5538** </dl>
5539**
5540** New status parameters may be added from time to time.
5541*/
5542#define SQLITE_STATUS_MEMORY_USED          0
5543#define SQLITE_STATUS_PAGECACHE_USED       1
5544#define SQLITE_STATUS_PAGECACHE_OVERFLOW   2
5545#define SQLITE_STATUS_SCRATCH_USED         3
5546#define SQLITE_STATUS_SCRATCH_OVERFLOW     4
5547#define SQLITE_STATUS_MALLOC_SIZE          5
5548#define SQLITE_STATUS_PARSER_STACK         6
5549#define SQLITE_STATUS_PAGECACHE_SIZE       7
5550#define SQLITE_STATUS_SCRATCH_SIZE         8
5551#define SQLITE_STATUS_MALLOC_COUNT         9
5552
5553/*
5554** CAPI3REF: Database Connection Status
5555**
5556** ^This interface is used to retrieve runtime status information
5557** about a single [database connection].  ^The first argument is the
5558** database connection object to be interrogated.  ^The second argument
5559** is an integer constant, taken from the set of
5560** [SQLITE_DBSTATUS_LOOKASIDE_USED | SQLITE_DBSTATUS_*] macros, that
5561** determines the parameter to interrogate.  The set of
5562** [SQLITE_DBSTATUS_LOOKASIDE_USED | SQLITE_DBSTATUS_*] macros is likely
5563** to grow in future releases of SQLite.
5564**
5565** ^The current value of the requested parameter is written into *pCur
5566** and the highest instantaneous value is written into *pHiwtr.  ^If
5567** the resetFlg is true, then the highest instantaneous value is
5568** reset back down to the current value.
5569**
5570** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
5571** non-zero [error code] on failure.
5572**
5573** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
5574*/
5575int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
5576
5577/*
5578** CAPI3REF: Status Parameters for database connections
5579**
5580** These constants are the available integer "verbs" that can be passed as
5581** the second argument to the [sqlite3_db_status()] interface.
5582**
5583** New verbs may be added in future releases of SQLite. Existing verbs
5584** might be discontinued. Applications should check the return code from
5585** [sqlite3_db_status()] to make sure that the call worked.
5586** The [sqlite3_db_status()] interface will return a non-zero error code
5587** if a discontinued or unsupported verb is invoked.
5588**
5589** <dl>
5590** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
5591** <dd>This parameter returns the number of lookaside memory slots currently
5592** checked out.</dd>)^
5593**
5594** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
5595** <dd>This parameter returns the number malloc attempts that were
5596** satisfied using lookaside memory. Only the high-water value is meaningful;
5597** the current value is always zero.)^
5598**
5599** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
5600** <dd>This parameter returns the number malloc attempts that might have
5601** been satisfied using lookaside memory but failed due to the amount of
5602** memory requested being larger than the lookaside slot size.
5603** Only the high-water value is meaningful;
5604** the current value is always zero.)^
5605**
5606** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
5607** <dd>This parameter returns the number malloc attempts that might have
5608** been satisfied using lookaside memory but failed due to all lookaside
5609** memory already being in use.
5610** Only the high-water value is meaningful;
5611** the current value is always zero.)^
5612**
5613** ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
5614** <dd>This parameter returns the approximate number of of bytes of heap
5615** memory used by all pager caches associated with the database connection.)^
5616** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
5617**
5618** ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
5619** <dd>This parameter returns the approximate number of of bytes of heap
5620** memory used to store the schema for all databases associated
5621** with the connection - main, temp, and any [ATTACH]-ed databases.)^
5622** ^The full amount of memory used by the schemas is reported, even if the
5623** schema memory is shared with other database connections due to
5624** [shared cache mode] being enabled.
5625** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
5626**
5627** ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
5628** <dd>This parameter returns the approximate number of of bytes of heap
5629** and lookaside memory used by all prepared statements associated with
5630** the database connection.)^
5631** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
5632** </dd>
5633** </dl>
5634*/
5635#define SQLITE_DBSTATUS_LOOKASIDE_USED       0
5636#define SQLITE_DBSTATUS_CACHE_USED           1
5637#define SQLITE_DBSTATUS_SCHEMA_USED          2
5638#define SQLITE_DBSTATUS_STMT_USED            3
5639#define SQLITE_DBSTATUS_LOOKASIDE_HIT        4
5640#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE  5
5641#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL  6
5642#define SQLITE_DBSTATUS_MAX                  6   /* Largest defined DBSTATUS */
5643
5644
5645/*
5646** CAPI3REF: Prepared Statement Status
5647**
5648** ^(Each prepared statement maintains various
5649** [SQLITE_STMTSTATUS_SORT | counters] that measure the number
5650** of times it has performed specific operations.)^  These counters can
5651** be used to monitor the performance characteristics of the prepared
5652** statements.  For example, if the number of table steps greatly exceeds
5653** the number of table searches or result rows, that would tend to indicate
5654** that the prepared statement is using a full table scan rather than
5655** an index.
5656**
5657** ^(This interface is used to retrieve and reset counter values from
5658** a [prepared statement].  The first argument is the prepared statement
5659** object to be interrogated.  The second argument
5660** is an integer code for a specific [SQLITE_STMTSTATUS_SORT | counter]
5661** to be interrogated.)^
5662** ^The current value of the requested counter is returned.
5663** ^If the resetFlg is true, then the counter is reset to zero after this
5664** interface call returns.
5665**
5666** See also: [sqlite3_status()] and [sqlite3_db_status()].
5667*/
5668int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
5669
5670/*
5671** CAPI3REF: Status Parameters for prepared statements
5672**
5673** These preprocessor macros define integer codes that name counter
5674** values associated with the [sqlite3_stmt_status()] interface.
5675** The meanings of the various counters are as follows:
5676**
5677** <dl>
5678** <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
5679** <dd>^This is the number of times that SQLite has stepped forward in
5680** a table as part of a full table scan.  Large numbers for this counter
5681** may indicate opportunities for performance improvement through
5682** careful use of indices.</dd>
5683**
5684** <dt>SQLITE_STMTSTATUS_SORT</dt>
5685** <dd>^This is the number of sort operations that have occurred.
5686** A non-zero value in this counter may indicate an opportunity to
5687** improvement performance through careful use of indices.</dd>
5688**
5689** <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
5690** <dd>^This is the number of rows inserted into transient indices that
5691** were created automatically in order to help joins run faster.
5692** A non-zero value in this counter may indicate an opportunity to
5693** improvement performance by adding permanent indices that do not
5694** need to be reinitialized each time the statement is run.</dd>
5695**
5696** </dl>
5697*/
5698#define SQLITE_STMTSTATUS_FULLSCAN_STEP     1
5699#define SQLITE_STMTSTATUS_SORT              2
5700#define SQLITE_STMTSTATUS_AUTOINDEX         3
5701
5702/*
5703** CAPI3REF: Custom Page Cache Object
5704**
5705** The sqlite3_pcache type is opaque.  It is implemented by
5706** the pluggable module.  The SQLite core has no knowledge of
5707** its size or internal structure and never deals with the
5708** sqlite3_pcache object except by holding and passing pointers
5709** to the object.
5710**
5711** See [sqlite3_pcache_methods] for additional information.
5712*/
5713typedef struct sqlite3_pcache sqlite3_pcache;
5714
5715/*
5716** CAPI3REF: Application Defined Page Cache.
5717** KEYWORDS: {page cache}
5718**
5719** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE], ...) interface can
5720** register an alternative page cache implementation by passing in an
5721** instance of the sqlite3_pcache_methods structure.)^
5722** In many applications, most of the heap memory allocated by
5723** SQLite is used for the page cache.
5724** By implementing a
5725** custom page cache using this API, an application can better control
5726** the amount of memory consumed by SQLite, the way in which
5727** that memory is allocated and released, and the policies used to
5728** determine exactly which parts of a database file are cached and for
5729** how long.
5730**
5731** The alternative page cache mechanism is an
5732** extreme measure that is only needed by the most demanding applications.
5733** The built-in page cache is recommended for most uses.
5734**
5735** ^(The contents of the sqlite3_pcache_methods structure are copied to an
5736** internal buffer by SQLite within the call to [sqlite3_config].  Hence
5737** the application may discard the parameter after the call to
5738** [sqlite3_config()] returns.)^
5739**
5740** ^(The xInit() method is called once for each effective
5741** call to [sqlite3_initialize()])^
5742** (usually only once during the lifetime of the process). ^(The xInit()
5743** method is passed a copy of the sqlite3_pcache_methods.pArg value.)^
5744** The intent of the xInit() method is to set up global data structures
5745** required by the custom page cache implementation.
5746** ^(If the xInit() method is NULL, then the
5747** built-in default page cache is used instead of the application defined
5748** page cache.)^
5749**
5750** ^The xShutdown() method is called by [sqlite3_shutdown()].
5751** It can be used to clean up
5752** any outstanding resources before process shutdown, if required.
5753** ^The xShutdown() method may be NULL.
5754**
5755** ^SQLite automatically serializes calls to the xInit method,
5756** so the xInit method need not be threadsafe.  ^The
5757** xShutdown method is only called from [sqlite3_shutdown()] so it does
5758** not need to be threadsafe either.  All other methods must be threadsafe
5759** in multithreaded applications.
5760**
5761** ^SQLite will never invoke xInit() more than once without an intervening
5762** call to xShutdown().
5763**
5764** ^SQLite invokes the xCreate() method to construct a new cache instance.
5765** SQLite will typically create one cache instance for each open database file,
5766** though this is not guaranteed. ^The
5767** first parameter, szPage, is the size in bytes of the pages that must
5768** be allocated by the cache.  ^szPage will not be a power of two.  ^szPage
5769** will the page size of the database file that is to be cached plus an
5770** increment (here called "R") of less than 250.  SQLite will use the
5771** extra R bytes on each page to store metadata about the underlying
5772** database page on disk.  The value of R depends
5773** on the SQLite version, the target platform, and how SQLite was compiled.
5774** ^(R is constant for a particular build of SQLite. Except, there are two
5775** distinct values of R when SQLite is compiled with the proprietary
5776** ZIPVFS extension.)^  ^The second argument to
5777** xCreate(), bPurgeable, is true if the cache being created will
5778** be used to cache database pages of a file stored on disk, or
5779** false if it is used for an in-memory database. The cache implementation
5780** does not have to do anything special based with the value of bPurgeable;
5781** it is purely advisory.  ^On a cache where bPurgeable is false, SQLite will
5782** never invoke xUnpin() except to deliberately delete a page.
5783** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
5784** false will always have the "discard" flag set to true.
5785** ^Hence, a cache created with bPurgeable false will
5786** never contain any unpinned pages.
5787**
5788** ^(The xCachesize() method may be called at any time by SQLite to set the
5789** suggested maximum cache-size (number of pages stored by) the cache
5790** instance passed as the first argument. This is the value configured using
5791** the SQLite "[PRAGMA cache_size]" command.)^  As with the bPurgeable
5792** parameter, the implementation is not required to do anything with this
5793** value; it is advisory only.
5794**
5795** The xPagecount() method must return the number of pages currently
5796** stored in the cache, both pinned and unpinned.
5797**
5798** The xFetch() method locates a page in the cache and returns a pointer to
5799** the page, or a NULL pointer.
5800** A "page", in this context, means a buffer of szPage bytes aligned at an
5801** 8-byte boundary. The page to be fetched is determined by the key. ^The
5802** mimimum key value is 1.  After it has been retrieved using xFetch, the page
5803** is considered to be "pinned".
5804**
5805** If the requested page is already in the page cache, then the page cache
5806** implementation must return a pointer to the page buffer with its content
5807** intact.  If the requested page is not already in the cache, then the
5808** cache implementation should use the value of the createFlag
5809** parameter to help it determined what action to take:
5810**
5811** <table border=1 width=85% align=center>
5812** <tr><th> createFlag <th> Behaviour when page is not already in cache
5813** <tr><td> 0 <td> Do not allocate a new page.  Return NULL.
5814** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
5815**                 Otherwise return NULL.
5816** <tr><td> 2 <td> Make every effort to allocate a new page.  Only return
5817**                 NULL if allocating a new page is effectively impossible.
5818** </table>
5819**
5820** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1.  SQLite
5821** will only use a createFlag of 2 after a prior call with a createFlag of 1
5822** failed.)^  In between the to xFetch() calls, SQLite may
5823** attempt to unpin one or more cache pages by spilling the content of
5824** pinned pages to disk and synching the operating system disk cache.
5825**
5826** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
5827** as its second argument.  If the third parameter, discard, is non-zero,
5828** then the page must be evicted from the cache.
5829** ^If the discard parameter is
5830** zero, then the page may be discarded or retained at the discretion of
5831** page cache implementation. ^The page cache implementation
5832** may choose to evict unpinned pages at any time.
5833**
5834** The cache must not perform any reference counting. A single
5835** call to xUnpin() unpins the page regardless of the number of prior calls
5836** to xFetch().
5837**
5838** The xRekey() method is used to change the key value associated with the
5839** page passed as the second argument. If the cache
5840** previously contains an entry associated with newKey, it must be
5841** discarded. ^Any prior cache entry associated with newKey is guaranteed not
5842** to be pinned.
5843**
5844** When SQLite calls the xTruncate() method, the cache must discard all
5845** existing cache entries with page numbers (keys) greater than or equal
5846** to the value of the iLimit parameter passed to xTruncate(). If any
5847** of these pages are pinned, they are implicitly unpinned, meaning that
5848** they can be safely discarded.
5849**
5850** ^The xDestroy() method is used to delete a cache allocated by xCreate().
5851** All resources associated with the specified cache should be freed. ^After
5852** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
5853** handle invalid, and will not use it with any other sqlite3_pcache_methods
5854** functions.
5855*/
5856typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
5857struct sqlite3_pcache_methods {
5858  void *pArg;
5859  int (*xInit)(void*);
5860  void (*xShutdown)(void*);
5861  sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
5862  void (*xCachesize)(sqlite3_pcache*, int nCachesize);
5863  int (*xPagecount)(sqlite3_pcache*);
5864  void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
5865  void (*xUnpin)(sqlite3_pcache*, void*, int discard);
5866  void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
5867  void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
5868  void (*xDestroy)(sqlite3_pcache*);
5869};
5870
5871/*
5872** CAPI3REF: Online Backup Object
5873**
5874** The sqlite3_backup object records state information about an ongoing
5875** online backup operation.  ^The sqlite3_backup object is created by
5876** a call to [sqlite3_backup_init()] and is destroyed by a call to
5877** [sqlite3_backup_finish()].
5878**
5879** See Also: [Using the SQLite Online Backup API]
5880*/
5881typedef struct sqlite3_backup sqlite3_backup;
5882
5883/*
5884** CAPI3REF: Online Backup API.
5885**
5886** The backup API copies the content of one database into another.
5887** It is useful either for creating backups of databases or
5888** for copying in-memory databases to or from persistent files.
5889**
5890** See Also: [Using the SQLite Online Backup API]
5891**
5892** ^SQLite holds a write transaction open on the destination database file
5893** for the duration of the backup operation.
5894** ^The source database is read-locked only while it is being read;
5895** it is not locked continuously for the entire backup operation.
5896** ^Thus, the backup may be performed on a live source database without
5897** preventing other database connections from
5898** reading or writing to the source database while the backup is underway.
5899**
5900** ^(To perform a backup operation:
5901**   <ol>
5902**     <li><b>sqlite3_backup_init()</b> is called once to initialize the
5903**         backup,
5904**     <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
5905**         the data between the two databases, and finally
5906**     <li><b>sqlite3_backup_finish()</b> is called to release all resources
5907**         associated with the backup operation.
5908**   </ol>)^
5909** There should be exactly one call to sqlite3_backup_finish() for each
5910** successful call to sqlite3_backup_init().
5911**
5912** <b>sqlite3_backup_init()</b>
5913**
5914** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
5915** [database connection] associated with the destination database
5916** and the database name, respectively.
5917** ^The database name is "main" for the main database, "temp" for the
5918** temporary database, or the name specified after the AS keyword in
5919** an [ATTACH] statement for an attached database.
5920** ^The S and M arguments passed to
5921** sqlite3_backup_init(D,N,S,M) identify the [database connection]
5922** and database name of the source database, respectively.
5923** ^The source and destination [database connections] (parameters S and D)
5924** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
5925** an error.
5926**
5927** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
5928** returned and an error code and error message are stored in the
5929** destination [database connection] D.
5930** ^The error code and message for the failed call to sqlite3_backup_init()
5931** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
5932** [sqlite3_errmsg16()] functions.
5933** ^A successful call to sqlite3_backup_init() returns a pointer to an
5934** [sqlite3_backup] object.
5935** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
5936** sqlite3_backup_finish() functions to perform the specified backup
5937** operation.
5938**
5939** <b>sqlite3_backup_step()</b>
5940**
5941** ^Function sqlite3_backup_step(B,N) will copy up to N pages between
5942** the source and destination databases specified by [sqlite3_backup] object B.
5943** ^If N is negative, all remaining source pages are copied.
5944** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
5945** are still more pages to be copied, then the function returns [SQLITE_OK].
5946** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
5947** from source to destination, then it returns [SQLITE_DONE].
5948** ^If an error occurs while running sqlite3_backup_step(B,N),
5949** then an [error code] is returned. ^As well as [SQLITE_OK] and
5950** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
5951** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
5952** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
5953**
5954** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
5955** <ol>
5956** <li> the destination database was opened read-only, or
5957** <li> the destination database is using write-ahead-log journaling
5958** and the destination and source page sizes differ, or
5959** <li> the destination database is an in-memory database and the
5960** destination and source page sizes differ.
5961** </ol>)^
5962**
5963** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
5964** the [sqlite3_busy_handler | busy-handler function]
5965** is invoked (if one is specified). ^If the
5966** busy-handler returns non-zero before the lock is available, then
5967** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
5968** sqlite3_backup_step() can be retried later. ^If the source
5969** [database connection]
5970** is being used to write to the source database when sqlite3_backup_step()
5971** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
5972** case the call to sqlite3_backup_step() can be retried later on. ^(If
5973** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
5974** [SQLITE_READONLY] is returned, then
5975** there is no point in retrying the call to sqlite3_backup_step(). These
5976** errors are considered fatal.)^  The application must accept
5977** that the backup operation has failed and pass the backup operation handle
5978** to the sqlite3_backup_finish() to release associated resources.
5979**
5980** ^The first call to sqlite3_backup_step() obtains an exclusive lock
5981** on the destination file. ^The exclusive lock is not released until either
5982** sqlite3_backup_finish() is called or the backup operation is complete
5983** and sqlite3_backup_step() returns [SQLITE_DONE].  ^Every call to
5984** sqlite3_backup_step() obtains a [shared lock] on the source database that
5985** lasts for the duration of the sqlite3_backup_step() call.
5986** ^Because the source database is not locked between calls to
5987** sqlite3_backup_step(), the source database may be modified mid-way
5988** through the backup process.  ^If the source database is modified by an
5989** external process or via a database connection other than the one being
5990** used by the backup operation, then the backup will be automatically
5991** restarted by the next call to sqlite3_backup_step(). ^If the source
5992** database is modified by the using the same database connection as is used
5993** by the backup operation, then the backup database is automatically
5994** updated at the same time.
5995**
5996** <b>sqlite3_backup_finish()</b>
5997**
5998** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the
5999** application wishes to abandon the backup operation, the application
6000** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
6001** ^The sqlite3_backup_finish() interfaces releases all
6002** resources associated with the [sqlite3_backup] object.
6003** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
6004** active write-transaction on the destination database is rolled back.
6005** The [sqlite3_backup] object is invalid
6006** and may not be used following a call to sqlite3_backup_finish().
6007**
6008** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
6009** sqlite3_backup_step() errors occurred, regardless or whether or not
6010** sqlite3_backup_step() completed.
6011** ^If an out-of-memory condition or IO error occurred during any prior
6012** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
6013** sqlite3_backup_finish() returns the corresponding [error code].
6014**
6015** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
6016** is not a permanent error and does not affect the return value of
6017** sqlite3_backup_finish().
6018**
6019** <b>sqlite3_backup_remaining(), sqlite3_backup_pagecount()</b>
6020**
6021** ^Each call to sqlite3_backup_step() sets two values inside
6022** the [sqlite3_backup] object: the number of pages still to be backed
6023** up and the total number of pages in the source database file.
6024** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces
6025** retrieve these two values, respectively.
6026**
6027** ^The values returned by these functions are only updated by
6028** sqlite3_backup_step(). ^If the source database is modified during a backup
6029** operation, then the values are not updated to account for any extra
6030** pages that need to be updated or the size of the source database file
6031** changing.
6032**
6033** <b>Concurrent Usage of Database Handles</b>
6034**
6035** ^The source [database connection] may be used by the application for other
6036** purposes while a backup operation is underway or being initialized.
6037** ^If SQLite is compiled and configured to support threadsafe database
6038** connections, then the source database connection may be used concurrently
6039** from within other threads.
6040**
6041** However, the application must guarantee that the destination
6042** [database connection] is not passed to any other API (by any thread) after
6043** sqlite3_backup_init() is called and before the corresponding call to
6044** sqlite3_backup_finish().  SQLite does not currently check to see
6045** if the application incorrectly accesses the destination [database connection]
6046** and so no error code is reported, but the operations may malfunction
6047** nevertheless.  Use of the destination database connection while a
6048** backup is in progress might also also cause a mutex deadlock.
6049**
6050** If running in [shared cache mode], the application must
6051** guarantee that the shared cache used by the destination database
6052** is not accessed while the backup is running. In practice this means
6053** that the application must guarantee that the disk file being
6054** backed up to is not accessed by any connection within the process,
6055** not just the specific connection that was passed to sqlite3_backup_init().
6056**
6057** The [sqlite3_backup] object itself is partially threadsafe. Multiple
6058** threads may safely make multiple concurrent calls to sqlite3_backup_step().
6059** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
6060** APIs are not strictly speaking threadsafe. If they are invoked at the
6061** same time as another thread is invoking sqlite3_backup_step() it is
6062** possible that they return invalid values.
6063*/
6064sqlite3_backup *sqlite3_backup_init(
6065  sqlite3 *pDest,                        /* Destination database handle */
6066  const char *zDestName,                 /* Destination database name */
6067  sqlite3 *pSource,                      /* Source database handle */
6068  const char *zSourceName                /* Source database name */
6069);
6070int sqlite3_backup_step(sqlite3_backup *p, int nPage);
6071int sqlite3_backup_finish(sqlite3_backup *p);
6072int sqlite3_backup_remaining(sqlite3_backup *p);
6073int sqlite3_backup_pagecount(sqlite3_backup *p);
6074
6075/*
6076** CAPI3REF: Unlock Notification
6077**
6078** ^When running in shared-cache mode, a database operation may fail with
6079** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
6080** individual tables within the shared-cache cannot be obtained. See
6081** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
6082** ^This API may be used to register a callback that SQLite will invoke
6083** when the connection currently holding the required lock relinquishes it.
6084** ^This API is only available if the library was compiled with the
6085** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
6086**
6087** See Also: [Using the SQLite Unlock Notification Feature].
6088**
6089** ^Shared-cache locks are released when a database connection concludes
6090** its current transaction, either by committing it or rolling it back.
6091**
6092** ^When a connection (known as the blocked connection) fails to obtain a
6093** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
6094** identity of the database connection (the blocking connection) that
6095** has locked the required resource is stored internally. ^After an
6096** application receives an SQLITE_LOCKED error, it may call the
6097** sqlite3_unlock_notify() method with the blocked connection handle as
6098** the first argument to register for a callback that will be invoked
6099** when the blocking connections current transaction is concluded. ^The
6100** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
6101** call that concludes the blocking connections transaction.
6102**
6103** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
6104** there is a chance that the blocking connection will have already
6105** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
6106** If this happens, then the specified callback is invoked immediately,
6107** from within the call to sqlite3_unlock_notify().)^
6108**
6109** ^If the blocked connection is attempting to obtain a write-lock on a
6110** shared-cache table, and more than one other connection currently holds
6111** a read-lock on the same table, then SQLite arbitrarily selects one of
6112** the other connections to use as the blocking connection.
6113**
6114** ^(There may be at most one unlock-notify callback registered by a
6115** blocked connection. If sqlite3_unlock_notify() is called when the
6116** blocked connection already has a registered unlock-notify callback,
6117** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
6118** called with a NULL pointer as its second argument, then any existing
6119** unlock-notify callback is canceled. ^The blocked connections
6120** unlock-notify callback may also be canceled by closing the blocked
6121** connection using [sqlite3_close()].
6122**
6123** The unlock-notify callback is not reentrant. If an application invokes
6124** any sqlite3_xxx API functions from within an unlock-notify callback, a
6125** crash or deadlock may be the result.
6126**
6127** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
6128** returns SQLITE_OK.
6129**
6130** <b>Callback Invocation Details</b>
6131**
6132** When an unlock-notify callback is registered, the application provides a
6133** single void* pointer that is passed to the callback when it is invoked.
6134** However, the signature of the callback function allows SQLite to pass
6135** it an array of void* context pointers. The first argument passed to
6136** an unlock-notify callback is a pointer to an array of void* pointers,
6137** and the second is the number of entries in the array.
6138**
6139** When a blocking connections transaction is concluded, there may be
6140** more than one blocked connection that has registered for an unlock-notify
6141** callback. ^If two or more such blocked connections have specified the
6142** same callback function, then instead of invoking the callback function
6143** multiple times, it is invoked once with the set of void* context pointers
6144** specified by the blocked connections bundled together into an array.
6145** This gives the application an opportunity to prioritize any actions
6146** related to the set of unblocked database connections.
6147**
6148** <b>Deadlock Detection</b>
6149**
6150** Assuming that after registering for an unlock-notify callback a
6151** database waits for the callback to be issued before taking any further
6152** action (a reasonable assumption), then using this API may cause the
6153** application to deadlock. For example, if connection X is waiting for
6154** connection Y's transaction to be concluded, and similarly connection
6155** Y is waiting on connection X's transaction, then neither connection
6156** will proceed and the system may remain deadlocked indefinitely.
6157**
6158** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
6159** detection. ^If a given call to sqlite3_unlock_notify() would put the
6160** system in a deadlocked state, then SQLITE_LOCKED is returned and no
6161** unlock-notify callback is registered. The system is said to be in
6162** a deadlocked state if connection A has registered for an unlock-notify
6163** callback on the conclusion of connection B's transaction, and connection
6164** B has itself registered for an unlock-notify callback when connection
6165** A's transaction is concluded. ^Indirect deadlock is also detected, so
6166** the system is also considered to be deadlocked if connection B has
6167** registered for an unlock-notify callback on the conclusion of connection
6168** C's transaction, where connection C is waiting on connection A. ^Any
6169** number of levels of indirection are allowed.
6170**
6171** <b>The "DROP TABLE" Exception</b>
6172**
6173** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost
6174** always appropriate to call sqlite3_unlock_notify(). There is however,
6175** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
6176** SQLite checks if there are any currently executing SELECT statements
6177** that belong to the same connection. If there are, SQLITE_LOCKED is
6178** returned. In this case there is no "blocking connection", so invoking
6179** sqlite3_unlock_notify() results in the unlock-notify callback being
6180** invoked immediately. If the application then re-attempts the "DROP TABLE"
6181** or "DROP INDEX" query, an infinite loop might be the result.
6182**
6183** One way around this problem is to check the extended error code returned
6184** by an sqlite3_step() call. ^(If there is a blocking connection, then the
6185** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
6186** the special "DROP TABLE/INDEX" case, the extended error code is just
6187** SQLITE_LOCKED.)^
6188*/
6189int sqlite3_unlock_notify(
6190  sqlite3 *pBlocked,                          /* Waiting connection */
6191  void (*xNotify)(void **apArg, int nArg),    /* Callback function to invoke */
6192  void *pNotifyArg                            /* Argument to pass to xNotify */
6193);
6194
6195
6196/*
6197** CAPI3REF: String Comparison
6198**
6199** ^The [sqlite3_strnicmp()] API allows applications and extensions to
6200** compare the contents of two buffers containing UTF-8 strings in a
6201** case-independent fashion, using the same definition of case independence
6202** that SQLite uses internally when comparing identifiers.
6203*/
6204int sqlite3_strnicmp(const char *, const char *, int);
6205
6206/*
6207** CAPI3REF: Error Logging Interface
6208**
6209** ^The [sqlite3_log()] interface writes a message into the error log
6210** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
6211** ^If logging is enabled, the zFormat string and subsequent arguments are
6212** used with [sqlite3_snprintf()] to generate the final output string.
6213**
6214** The sqlite3_log() interface is intended for use by extensions such as
6215** virtual tables, collating functions, and SQL functions.  While there is
6216** nothing to prevent an application from calling sqlite3_log(), doing so
6217** is considered bad form.
6218**
6219** The zFormat string must not be NULL.
6220**
6221** To avoid deadlocks and other threading problems, the sqlite3_log() routine
6222** will not use dynamically allocated memory.  The log message is stored in
6223** a fixed-length buffer on the stack.  If the log message is longer than
6224** a few hundred characters, it will be truncated to the length of the
6225** buffer.
6226*/
6227void sqlite3_log(int iErrCode, const char *zFormat, ...);
6228
6229/*
6230** CAPI3REF: Write-Ahead Log Commit Hook
6231**
6232** ^The [sqlite3_wal_hook()] function is used to register a callback that
6233** will be invoked each time a database connection commits data to a
6234** [write-ahead log] (i.e. whenever a transaction is committed in
6235** [journal_mode | journal_mode=WAL mode]).
6236**
6237** ^The callback is invoked by SQLite after the commit has taken place and
6238** the associated write-lock on the database released, so the implementation
6239** may read, write or [checkpoint] the database as required.
6240**
6241** ^The first parameter passed to the callback function when it is invoked
6242** is a copy of the third parameter passed to sqlite3_wal_hook() when
6243** registering the callback. ^The second is a copy of the database handle.
6244** ^The third parameter is the name of the database that was written to -
6245** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
6246** is the number of pages currently in the write-ahead log file,
6247** including those that were just committed.
6248**
6249** The callback function should normally return [SQLITE_OK].  ^If an error
6250** code is returned, that error will propagate back up through the
6251** SQLite code base to cause the statement that provoked the callback
6252** to report an error, though the commit will have still occurred. If the
6253** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
6254** that does not correspond to any valid SQLite error code, the results
6255** are undefined.
6256**
6257** A single database handle may have at most a single write-ahead log callback
6258** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
6259** previously registered write-ahead log callback. ^Note that the
6260** [sqlite3_wal_autocheckpoint()] interface and the
6261** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
6262** those overwrite any prior [sqlite3_wal_hook()] settings.
6263*/
6264void *sqlite3_wal_hook(
6265  sqlite3*,
6266  int(*)(void *,sqlite3*,const char*,int),
6267  void*
6268);
6269
6270/*
6271** CAPI3REF: Configure an auto-checkpoint
6272**
6273** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
6274** [sqlite3_wal_hook()] that causes any database on [database connection] D
6275** to automatically [checkpoint]
6276** after committing a transaction if there are N or
6277** more frames in the [write-ahead log] file.  ^Passing zero or
6278** a negative value as the nFrame parameter disables automatic
6279** checkpoints entirely.
6280**
6281** ^The callback registered by this function replaces any existing callback
6282** registered using [sqlite3_wal_hook()].  ^Likewise, registering a callback
6283** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
6284** configured by this function.
6285**
6286** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
6287** from SQL.
6288**
6289** ^Every new [database connection] defaults to having the auto-checkpoint
6290** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
6291** pages.  The use of this interface
6292** is only necessary if the default setting is found to be suboptimal
6293** for a particular application.
6294*/
6295int sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
6296
6297/*
6298** CAPI3REF: Checkpoint a database
6299**
6300** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X
6301** on [database connection] D to be [checkpointed].  ^If X is NULL or an
6302** empty string, then a checkpoint is run on all databases of
6303** connection D.  ^If the database connection D is not in
6304** [WAL | write-ahead log mode] then this interface is a harmless no-op.
6305**
6306** ^The [wal_checkpoint pragma] can be used to invoke this interface
6307** from SQL.  ^The [sqlite3_wal_autocheckpoint()] interface and the
6308** [wal_autocheckpoint pragma] can be used to cause this interface to be
6309** run whenever the WAL reaches a certain size threshold.
6310**
6311** See also: [sqlite3_wal_checkpoint_v2()]
6312*/
6313int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
6314
6315/*
6316** CAPI3REF: Checkpoint a database
6317**
6318** Run a checkpoint operation on WAL database zDb attached to database
6319** handle db. The specific operation is determined by the value of the
6320** eMode parameter:
6321**
6322** <dl>
6323** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
6324**   Checkpoint as many frames as possible without waiting for any database
6325**   readers or writers to finish. Sync the db file if all frames in the log
6326**   are checkpointed. This mode is the same as calling
6327**   sqlite3_wal_checkpoint(). The busy-handler callback is never invoked.
6328**
6329** <dt>SQLITE_CHECKPOINT_FULL<dd>
6330**   This mode blocks (calls the busy-handler callback) until there is no
6331**   database writer and all readers are reading from the most recent database
6332**   snapshot. It then checkpoints all frames in the log file and syncs the
6333**   database file. This call blocks database writers while it is running,
6334**   but not database readers.
6335**
6336** <dt>SQLITE_CHECKPOINT_RESTART<dd>
6337**   This mode works the same way as SQLITE_CHECKPOINT_FULL, except after
6338**   checkpointing the log file it blocks (calls the busy-handler callback)
6339**   until all readers are reading from the database file only. This ensures
6340**   that the next client to write to the database file restarts the log file
6341**   from the beginning. This call blocks database writers while it is running,
6342**   but not database readers.
6343** </dl>
6344**
6345** If pnLog is not NULL, then *pnLog is set to the total number of frames in
6346** the log file before returning. If pnCkpt is not NULL, then *pnCkpt is set to
6347** the total number of checkpointed frames (including any that were already
6348** checkpointed when this function is called). *pnLog and *pnCkpt may be
6349** populated even if sqlite3_wal_checkpoint_v2() returns other than SQLITE_OK.
6350** If no values are available because of an error, they are both set to -1
6351** before returning to communicate this to the caller.
6352**
6353** All calls obtain an exclusive "checkpoint" lock on the database file. If
6354** any other process is running a checkpoint operation at the same time, the
6355** lock cannot be obtained and SQLITE_BUSY is returned. Even if there is a
6356** busy-handler configured, it will not be invoked in this case.
6357**
6358** The SQLITE_CHECKPOINT_FULL and RESTART modes also obtain the exclusive
6359** "writer" lock on the database file. If the writer lock cannot be obtained
6360** immediately, and a busy-handler is configured, it is invoked and the writer
6361** lock retried until either the busy-handler returns 0 or the lock is
6362** successfully obtained. The busy-handler is also invoked while waiting for
6363** database readers as described above. If the busy-handler returns 0 before
6364** the writer lock is obtained or while waiting for database readers, the
6365** checkpoint operation proceeds from that point in the same way as
6366** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible
6367** without blocking any further. SQLITE_BUSY is returned in this case.
6368**
6369** If parameter zDb is NULL or points to a zero length string, then the
6370** specified operation is attempted on all WAL databases. In this case the
6371** values written to output parameters *pnLog and *pnCkpt are undefined. If
6372** an SQLITE_BUSY error is encountered when processing one or more of the
6373** attached WAL databases, the operation is still attempted on any remaining
6374** attached databases and SQLITE_BUSY is returned to the caller. If any other
6375** error occurs while processing an attached database, processing is abandoned
6376** and the error code returned to the caller immediately. If no error
6377** (SQLITE_BUSY or otherwise) is encountered while processing the attached
6378** databases, SQLITE_OK is returned.
6379**
6380** If database zDb is the name of an attached database that is not in WAL
6381** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. If
6382** zDb is not NULL (or a zero length string) and is not the name of any
6383** attached database, SQLITE_ERROR is returned to the caller.
6384*/
6385int sqlite3_wal_checkpoint_v2(
6386  sqlite3 *db,                    /* Database handle */
6387  const char *zDb,                /* Name of attached database (or NULL) */
6388  int eMode,                      /* SQLITE_CHECKPOINT_* value */
6389  int *pnLog,                     /* OUT: Size of WAL log in frames */
6390  int *pnCkpt                     /* OUT: Total number of frames checkpointed */
6391);
6392
6393/*
6394** CAPI3REF: Checkpoint operation parameters
6395**
6396** These constants can be used as the 3rd parameter to
6397** [sqlite3_wal_checkpoint_v2()].  See the [sqlite3_wal_checkpoint_v2()]
6398** documentation for additional information about the meaning and use of
6399** each of these values.
6400*/
6401#define SQLITE_CHECKPOINT_PASSIVE 0
6402#define SQLITE_CHECKPOINT_FULL    1
6403#define SQLITE_CHECKPOINT_RESTART 2
6404
6405
6406/* Begin recover.patch for Chromium */
6407/*
6408** Call to initialize the recover virtual-table modules (see recover.c).
6409**
6410** This could be loaded by default in main.c, but that would make the
6411** virtual table available to Web SQL.  Breaking it out allows only
6412** selected users to enable it (currently sql/recovery.cc).
6413*/
6414int recoverVtableInit(sqlite3 *db);
6415/* End recover.patch for Chromium */
6416
6417/*
6418** Undo the hack that converts floating point types to integer for
6419** builds on processors without floating point support.
6420*/
6421#ifdef SQLITE_OMIT_FLOATING_POINT
6422# undef double
6423#endif
6424
6425#ifdef __cplusplus
6426}  /* End of the 'extern "C"' block */
6427#endif
6428#endif
6429