sqlite3.h revision 289166
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 supposed 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** Provide the ability to override linkage features of the interface.
47*/
48#ifndef SQLITE_EXTERN
49# define SQLITE_EXTERN extern
50#endif
51#ifndef SQLITE_API
52# define SQLITE_API
53#endif
54#ifndef SQLITE_CDECL
55# define SQLITE_CDECL
56#endif
57#ifndef SQLITE_STDCALL
58# define SQLITE_STDCALL
59#endif
60
61/*
62** These no-op macros are used in front of interfaces to mark those
63** interfaces as either deprecated or experimental.  New applications
64** should not use deprecated interfaces - they are supported for backwards
65** compatibility only.  Application writers should be aware that
66** experimental interfaces are subject to change in point releases.
67**
68** These macros used to resolve to various kinds of compiler magic that
69** would generate warning messages when they were used.  But that
70** compiler magic ended up generating such a flurry of bug reports
71** that we have taken it all out and gone back to using simple
72** noop macros.
73*/
74#define SQLITE_DEPRECATED
75#define SQLITE_EXPERIMENTAL
76
77/*
78** Ensure these symbols were not defined by some previous header file.
79*/
80#ifdef SQLITE_VERSION
81# undef SQLITE_VERSION
82#endif
83#ifdef SQLITE_VERSION_NUMBER
84# undef SQLITE_VERSION_NUMBER
85#endif
86
87/*
88** CAPI3REF: Compile-Time Library Version Numbers
89**
90** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header
91** evaluates to a string literal that is the SQLite version in the
92** format "X.Y.Z" where X is the major version number (always 3 for
93** SQLite3) and Y is the minor version number and Z is the release number.)^
94** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer
95** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same
96** numbers used in [SQLITE_VERSION].)^
97** The SQLITE_VERSION_NUMBER for any given release of SQLite will also
98** be larger than the release from which it is derived.  Either Y will
99** be held constant and Z will be incremented or else Y will be incremented
100** and Z will be reset to zero.
101**
102** Since version 3.6.18, SQLite source code has been stored in the
103** <a href="http://www.fossil-scm.org/">Fossil configuration management
104** system</a>.  ^The SQLITE_SOURCE_ID macro evaluates to
105** a string which identifies a particular check-in of SQLite
106** within its configuration management system.  ^The SQLITE_SOURCE_ID
107** string contains the date and time of the check-in (UTC) and an SHA1
108** hash of the entire source tree.
109**
110** See also: [sqlite3_libversion()],
111** [sqlite3_libversion_number()], [sqlite3_sourceid()],
112** [sqlite_version()] and [sqlite_source_id()].
113*/
114#define SQLITE_VERSION        "3.8.11.1"
115#define SQLITE_VERSION_NUMBER 3008011
116#define SQLITE_SOURCE_ID      "2015-07-29 20:00:57 cf538e2783e468bbc25e7cb2a9ee64d3e0e80b2f"
117
118/*
119** CAPI3REF: Run-Time Library Version Numbers
120** KEYWORDS: sqlite3_version, sqlite3_sourceid
121**
122** These interfaces provide the same information as the [SQLITE_VERSION],
123** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros
124** but are associated with the library instead of the header file.  ^(Cautious
125** programmers might include assert() statements in their application to
126** verify that values returned by these interfaces match the macros in
127** the header, and thus insure that the application is
128** compiled with matching library and header files.
129**
130** <blockquote><pre>
131** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
132** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 );
133** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
134** </pre></blockquote>)^
135**
136** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION]
137** macro.  ^The sqlite3_libversion() function returns a pointer to the
138** to the sqlite3_version[] string constant.  The sqlite3_libversion()
139** function is provided for use in DLLs since DLL users usually do not have
140** direct access to string constants within the DLL.  ^The
141** sqlite3_libversion_number() function returns an integer equal to
142** [SQLITE_VERSION_NUMBER].  ^The sqlite3_sourceid() function returns
143** a pointer to a string constant whose value is the same as the
144** [SQLITE_SOURCE_ID] C preprocessor macro.
145**
146** See also: [sqlite_version()] and [sqlite_source_id()].
147*/
148SQLITE_API SQLITE_EXTERN const char sqlite3_version[];
149SQLITE_API const char *SQLITE_STDCALL sqlite3_libversion(void);
150SQLITE_API const char *SQLITE_STDCALL sqlite3_sourceid(void);
151SQLITE_API int SQLITE_STDCALL sqlite3_libversion_number(void);
152
153/*
154** CAPI3REF: Run-Time Library Compilation Options Diagnostics
155**
156** ^The sqlite3_compileoption_used() function returns 0 or 1
157** indicating whether the specified option was defined at
158** compile time.  ^The SQLITE_ prefix may be omitted from the
159** option name passed to sqlite3_compileoption_used().
160**
161** ^The sqlite3_compileoption_get() function allows iterating
162** over the list of options that were defined at compile time by
163** returning the N-th compile time option string.  ^If N is out of range,
164** sqlite3_compileoption_get() returns a NULL pointer.  ^The SQLITE_
165** prefix is omitted from any strings returned by
166** sqlite3_compileoption_get().
167**
168** ^Support for the diagnostic functions sqlite3_compileoption_used()
169** and sqlite3_compileoption_get() may be omitted by specifying the
170** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time.
171**
172** See also: SQL functions [sqlite_compileoption_used()] and
173** [sqlite_compileoption_get()] and the [compile_options pragma].
174*/
175#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
176SQLITE_API int SQLITE_STDCALL sqlite3_compileoption_used(const char *zOptName);
177SQLITE_API const char *SQLITE_STDCALL sqlite3_compileoption_get(int N);
178#endif
179
180/*
181** CAPI3REF: Test To See If The Library Is Threadsafe
182**
183** ^The sqlite3_threadsafe() function returns zero if and only if
184** SQLite was compiled with mutexing code omitted due to the
185** [SQLITE_THREADSAFE] compile-time option being set to 0.
186**
187** SQLite can be compiled with or without mutexes.  When
188** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
189** are enabled and SQLite is threadsafe.  When the
190** [SQLITE_THREADSAFE] macro is 0,
191** the mutexes are omitted.  Without the mutexes, it is not safe
192** to use SQLite concurrently from more than one thread.
193**
194** Enabling mutexes incurs a measurable performance penalty.
195** So if speed is of utmost importance, it makes sense to disable
196** the mutexes.  But for maximum safety, mutexes should be enabled.
197** ^The default behavior is for mutexes to be enabled.
198**
199** This interface can be used by an application to make sure that the
200** version of SQLite that it is linking against was compiled with
201** the desired setting of the [SQLITE_THREADSAFE] macro.
202**
203** This interface only reports on the compile-time mutex setting
204** of the [SQLITE_THREADSAFE] flag.  If SQLite is compiled with
205** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
206** can be fully or partially disabled using a call to [sqlite3_config()]
207** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD],
208** or [SQLITE_CONFIG_SERIALIZED].  ^(The return value of the
209** sqlite3_threadsafe() function shows only the compile-time setting of
210** thread safety, not any run-time changes to that setting made by
211** sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
212** is unchanged by calls to sqlite3_config().)^
213**
214** See the [threading mode] documentation for additional information.
215*/
216SQLITE_API int SQLITE_STDCALL sqlite3_threadsafe(void);
217
218/*
219** CAPI3REF: Database Connection Handle
220** KEYWORDS: {database connection} {database connections}
221**
222** Each open SQLite database is represented by a pointer to an instance of
223** the opaque structure named "sqlite3".  It is useful to think of an sqlite3
224** pointer as an object.  The [sqlite3_open()], [sqlite3_open16()], and
225** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
226** and [sqlite3_close_v2()] are its destructors.  There are many other
227** interfaces (such as
228** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
229** [sqlite3_busy_timeout()] to name but three) that are methods on an
230** sqlite3 object.
231*/
232typedef struct sqlite3 sqlite3;
233
234/*
235** CAPI3REF: 64-Bit Integer Types
236** KEYWORDS: sqlite_int64 sqlite_uint64
237**
238** Because there is no cross-platform way to specify 64-bit integer types
239** SQLite includes typedefs for 64-bit signed and unsigned integers.
240**
241** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
242** The sqlite_int64 and sqlite_uint64 types are supported for backwards
243** compatibility only.
244**
245** ^The sqlite3_int64 and sqlite_int64 types can store integer values
246** between -9223372036854775808 and +9223372036854775807 inclusive.  ^The
247** sqlite3_uint64 and sqlite_uint64 types can store integer values
248** between 0 and +18446744073709551615 inclusive.
249*/
250#ifdef SQLITE_INT64_TYPE
251  typedef SQLITE_INT64_TYPE sqlite_int64;
252  typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
253#elif defined(_MSC_VER) || defined(__BORLANDC__)
254  typedef __int64 sqlite_int64;
255  typedef unsigned __int64 sqlite_uint64;
256#else
257  typedef long long int sqlite_int64;
258  typedef unsigned long long int sqlite_uint64;
259#endif
260typedef sqlite_int64 sqlite3_int64;
261typedef sqlite_uint64 sqlite3_uint64;
262
263/*
264** If compiling for a processor that lacks floating point support,
265** substitute integer for floating-point.
266*/
267#ifdef SQLITE_OMIT_FLOATING_POINT
268# define double sqlite3_int64
269#endif
270
271/*
272** CAPI3REF: Closing A Database Connection
273** DESTRUCTOR: sqlite3
274**
275** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors
276** for the [sqlite3] object.
277** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if
278** the [sqlite3] object is successfully destroyed and all associated
279** resources are deallocated.
280**
281** ^If the database connection is associated with unfinalized prepared
282** statements or unfinished sqlite3_backup objects then sqlite3_close()
283** will leave the database connection open and return [SQLITE_BUSY].
284** ^If sqlite3_close_v2() is called with unfinalized prepared statements
285** and/or unfinished sqlite3_backups, then the database connection becomes
286** an unusable "zombie" which will automatically be deallocated when the
287** last prepared statement is finalized or the last sqlite3_backup is
288** finished.  The sqlite3_close_v2() interface is intended for use with
289** host languages that are garbage collected, and where the order in which
290** destructors are called is arbitrary.
291**
292** Applications should [sqlite3_finalize | finalize] all [prepared statements],
293** [sqlite3_blob_close | close] all [BLOB handles], and
294** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated
295** with the [sqlite3] object prior to attempting to close the object.  ^If
296** sqlite3_close_v2() is called on a [database connection] that still has
297** outstanding [prepared statements], [BLOB handles], and/or
298** [sqlite3_backup] objects then it returns [SQLITE_OK] and the deallocation
299** of resources is deferred until all [prepared statements], [BLOB handles],
300** and [sqlite3_backup] objects are also destroyed.
301**
302** ^If an [sqlite3] object is destroyed while a transaction is open,
303** the transaction is automatically rolled back.
304**
305** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)]
306** must be either a NULL
307** pointer or an [sqlite3] object pointer obtained
308** from [sqlite3_open()], [sqlite3_open16()], or
309** [sqlite3_open_v2()], and not previously closed.
310** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer
311** argument is a harmless no-op.
312*/
313SQLITE_API int SQLITE_STDCALL sqlite3_close(sqlite3*);
314SQLITE_API int SQLITE_STDCALL sqlite3_close_v2(sqlite3*);
315
316/*
317** The type for a callback function.
318** This is legacy and deprecated.  It is included for historical
319** compatibility and is not documented.
320*/
321typedef int (*sqlite3_callback)(void*,int,char**, char**);
322
323/*
324** CAPI3REF: One-Step Query Execution Interface
325** METHOD: sqlite3
326**
327** The sqlite3_exec() interface is a convenience wrapper around
328** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
329** that allows an application to run multiple statements of SQL
330** without having to use a lot of C code.
331**
332** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
333** semicolon-separate SQL statements passed into its 2nd argument,
334** in the context of the [database connection] passed in as its 1st
335** argument.  ^If the callback function of the 3rd argument to
336** sqlite3_exec() is not NULL, then it is invoked for each result row
337** coming out of the evaluated SQL statements.  ^The 4th argument to
338** sqlite3_exec() is relayed through to the 1st argument of each
339** callback invocation.  ^If the callback pointer to sqlite3_exec()
340** is NULL, then no callback is ever invoked and result rows are
341** ignored.
342**
343** ^If an error occurs while evaluating the SQL statements passed into
344** sqlite3_exec(), then execution of the current statement stops and
345** subsequent statements are skipped.  ^If the 5th parameter to sqlite3_exec()
346** is not NULL then any error message is written into memory obtained
347** from [sqlite3_malloc()] and passed back through the 5th parameter.
348** To avoid memory leaks, the application should invoke [sqlite3_free()]
349** on error message strings returned through the 5th parameter of
350** of sqlite3_exec() after the error message string is no longer needed.
351** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
352** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
353** NULL before returning.
354**
355** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
356** routine returns SQLITE_ABORT without invoking the callback again and
357** without running any subsequent SQL statements.
358**
359** ^The 2nd argument to the sqlite3_exec() callback function is the
360** number of columns in the result.  ^The 3rd argument to the sqlite3_exec()
361** callback is an array of pointers to strings obtained as if from
362** [sqlite3_column_text()], one for each column.  ^If an element of a
363** result row is NULL then the corresponding string pointer for the
364** sqlite3_exec() callback is a NULL pointer.  ^The 4th argument to the
365** sqlite3_exec() callback is an array of pointers to strings where each
366** entry represents the name of corresponding result column as obtained
367** from [sqlite3_column_name()].
368**
369** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
370** to an empty string, or a pointer that contains only whitespace and/or
371** SQL comments, then no SQL statements are evaluated and the database
372** is not changed.
373**
374** Restrictions:
375**
376** <ul>
377** <li> The application must insure that the 1st parameter to sqlite3_exec()
378**      is a valid and open [database connection].
379** <li> The application must not close the [database connection] specified by
380**      the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
381** <li> The application must not modify the SQL statement text passed into
382**      the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
383** </ul>
384*/
385SQLITE_API int SQLITE_STDCALL sqlite3_exec(
386  sqlite3*,                                  /* An open database */
387  const char *sql,                           /* SQL to be evaluated */
388  int (*callback)(void*,int,char**,char**),  /* Callback function */
389  void *,                                    /* 1st argument to callback */
390  char **errmsg                              /* Error msg written here */
391);
392
393/*
394** CAPI3REF: Result Codes
395** KEYWORDS: {result code definitions}
396**
397** Many SQLite functions return an integer result code from the set shown
398** here in order to indicate success or failure.
399**
400** New error codes may be added in future versions of SQLite.
401**
402** See also: [extended result code definitions]
403*/
404#define SQLITE_OK           0   /* Successful result */
405/* beginning-of-error-codes */
406#define SQLITE_ERROR        1   /* SQL error or missing database */
407#define SQLITE_INTERNAL     2   /* Internal logic error in SQLite */
408#define SQLITE_PERM         3   /* Access permission denied */
409#define SQLITE_ABORT        4   /* Callback routine requested an abort */
410#define SQLITE_BUSY         5   /* The database file is locked */
411#define SQLITE_LOCKED       6   /* A table in the database is locked */
412#define SQLITE_NOMEM        7   /* A malloc() failed */
413#define SQLITE_READONLY     8   /* Attempt to write a readonly database */
414#define SQLITE_INTERRUPT    9   /* Operation terminated by sqlite3_interrupt()*/
415#define SQLITE_IOERR       10   /* Some kind of disk I/O error occurred */
416#define SQLITE_CORRUPT     11   /* The database disk image is malformed */
417#define SQLITE_NOTFOUND    12   /* Unknown opcode in sqlite3_file_control() */
418#define SQLITE_FULL        13   /* Insertion failed because database is full */
419#define SQLITE_CANTOPEN    14   /* Unable to open the database file */
420#define SQLITE_PROTOCOL    15   /* Database lock protocol error */
421#define SQLITE_EMPTY       16   /* Database is empty */
422#define SQLITE_SCHEMA      17   /* The database schema changed */
423#define SQLITE_TOOBIG      18   /* String or BLOB exceeds size limit */
424#define SQLITE_CONSTRAINT  19   /* Abort due to constraint violation */
425#define SQLITE_MISMATCH    20   /* Data type mismatch */
426#define SQLITE_MISUSE      21   /* Library used incorrectly */
427#define SQLITE_NOLFS       22   /* Uses OS features not supported on host */
428#define SQLITE_AUTH        23   /* Authorization denied */
429#define SQLITE_FORMAT      24   /* Auxiliary database format error */
430#define SQLITE_RANGE       25   /* 2nd parameter to sqlite3_bind out of range */
431#define SQLITE_NOTADB      26   /* File opened that is not a database file */
432#define SQLITE_NOTICE      27   /* Notifications from sqlite3_log() */
433#define SQLITE_WARNING     28   /* Warnings from sqlite3_log() */
434#define SQLITE_ROW         100  /* sqlite3_step() has another row ready */
435#define SQLITE_DONE        101  /* sqlite3_step() has finished executing */
436/* end-of-error-codes */
437
438/*
439** CAPI3REF: Extended Result Codes
440** KEYWORDS: {extended result code definitions}
441**
442** In its default configuration, SQLite API routines return one of 30 integer
443** [result codes].  However, experience has shown that many of
444** these result codes are too coarse-grained.  They do not provide as
445** much information about problems as programmers might like.  In an effort to
446** address this, newer versions of SQLite (version 3.3.8 and later) include
447** support for additional result codes that provide more detailed information
448** about errors. These [extended result codes] are enabled or disabled
449** on a per database connection basis using the
450** [sqlite3_extended_result_codes()] API.  Or, the extended code for
451** the most recent error can be obtained using
452** [sqlite3_extended_errcode()].
453*/
454#define SQLITE_IOERR_READ              (SQLITE_IOERR | (1<<8))
455#define SQLITE_IOERR_SHORT_READ        (SQLITE_IOERR | (2<<8))
456#define SQLITE_IOERR_WRITE             (SQLITE_IOERR | (3<<8))
457#define SQLITE_IOERR_FSYNC             (SQLITE_IOERR | (4<<8))
458#define SQLITE_IOERR_DIR_FSYNC         (SQLITE_IOERR | (5<<8))
459#define SQLITE_IOERR_TRUNCATE          (SQLITE_IOERR | (6<<8))
460#define SQLITE_IOERR_FSTAT             (SQLITE_IOERR | (7<<8))
461#define SQLITE_IOERR_UNLOCK            (SQLITE_IOERR | (8<<8))
462#define SQLITE_IOERR_RDLOCK            (SQLITE_IOERR | (9<<8))
463#define SQLITE_IOERR_DELETE            (SQLITE_IOERR | (10<<8))
464#define SQLITE_IOERR_BLOCKED           (SQLITE_IOERR | (11<<8))
465#define SQLITE_IOERR_NOMEM             (SQLITE_IOERR | (12<<8))
466#define SQLITE_IOERR_ACCESS            (SQLITE_IOERR | (13<<8))
467#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
468#define SQLITE_IOERR_LOCK              (SQLITE_IOERR | (15<<8))
469#define SQLITE_IOERR_CLOSE             (SQLITE_IOERR | (16<<8))
470#define SQLITE_IOERR_DIR_CLOSE         (SQLITE_IOERR | (17<<8))
471#define SQLITE_IOERR_SHMOPEN           (SQLITE_IOERR | (18<<8))
472#define SQLITE_IOERR_SHMSIZE           (SQLITE_IOERR | (19<<8))
473#define SQLITE_IOERR_SHMLOCK           (SQLITE_IOERR | (20<<8))
474#define SQLITE_IOERR_SHMMAP            (SQLITE_IOERR | (21<<8))
475#define SQLITE_IOERR_SEEK              (SQLITE_IOERR | (22<<8))
476#define SQLITE_IOERR_DELETE_NOENT      (SQLITE_IOERR | (23<<8))
477#define SQLITE_IOERR_MMAP              (SQLITE_IOERR | (24<<8))
478#define SQLITE_IOERR_GETTEMPPATH       (SQLITE_IOERR | (25<<8))
479#define SQLITE_IOERR_CONVPATH          (SQLITE_IOERR | (26<<8))
480#define SQLITE_LOCKED_SHAREDCACHE      (SQLITE_LOCKED |  (1<<8))
481#define SQLITE_BUSY_RECOVERY           (SQLITE_BUSY   |  (1<<8))
482#define SQLITE_BUSY_SNAPSHOT           (SQLITE_BUSY   |  (2<<8))
483#define SQLITE_CANTOPEN_NOTEMPDIR      (SQLITE_CANTOPEN | (1<<8))
484#define SQLITE_CANTOPEN_ISDIR          (SQLITE_CANTOPEN | (2<<8))
485#define SQLITE_CANTOPEN_FULLPATH       (SQLITE_CANTOPEN | (3<<8))
486#define SQLITE_CANTOPEN_CONVPATH       (SQLITE_CANTOPEN | (4<<8))
487#define SQLITE_CORRUPT_VTAB            (SQLITE_CORRUPT | (1<<8))
488#define SQLITE_READONLY_RECOVERY       (SQLITE_READONLY | (1<<8))
489#define SQLITE_READONLY_CANTLOCK       (SQLITE_READONLY | (2<<8))
490#define SQLITE_READONLY_ROLLBACK       (SQLITE_READONLY | (3<<8))
491#define SQLITE_READONLY_DBMOVED        (SQLITE_READONLY | (4<<8))
492#define SQLITE_ABORT_ROLLBACK          (SQLITE_ABORT | (2<<8))
493#define SQLITE_CONSTRAINT_CHECK        (SQLITE_CONSTRAINT | (1<<8))
494#define SQLITE_CONSTRAINT_COMMITHOOK   (SQLITE_CONSTRAINT | (2<<8))
495#define SQLITE_CONSTRAINT_FOREIGNKEY   (SQLITE_CONSTRAINT | (3<<8))
496#define SQLITE_CONSTRAINT_FUNCTION     (SQLITE_CONSTRAINT | (4<<8))
497#define SQLITE_CONSTRAINT_NOTNULL      (SQLITE_CONSTRAINT | (5<<8))
498#define SQLITE_CONSTRAINT_PRIMARYKEY   (SQLITE_CONSTRAINT | (6<<8))
499#define SQLITE_CONSTRAINT_TRIGGER      (SQLITE_CONSTRAINT | (7<<8))
500#define SQLITE_CONSTRAINT_UNIQUE       (SQLITE_CONSTRAINT | (8<<8))
501#define SQLITE_CONSTRAINT_VTAB         (SQLITE_CONSTRAINT | (9<<8))
502#define SQLITE_CONSTRAINT_ROWID        (SQLITE_CONSTRAINT |(10<<8))
503#define SQLITE_NOTICE_RECOVER_WAL      (SQLITE_NOTICE | (1<<8))
504#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8))
505#define SQLITE_WARNING_AUTOINDEX       (SQLITE_WARNING | (1<<8))
506#define SQLITE_AUTH_USER               (SQLITE_AUTH | (1<<8))
507
508/*
509** CAPI3REF: Flags For File Open Operations
510**
511** These bit values are intended for use in the
512** 3rd parameter to the [sqlite3_open_v2()] interface and
513** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
514*/
515#define SQLITE_OPEN_READONLY         0x00000001  /* Ok for sqlite3_open_v2() */
516#define SQLITE_OPEN_READWRITE        0x00000002  /* Ok for sqlite3_open_v2() */
517#define SQLITE_OPEN_CREATE           0x00000004  /* Ok for sqlite3_open_v2() */
518#define SQLITE_OPEN_DELETEONCLOSE    0x00000008  /* VFS only */
519#define SQLITE_OPEN_EXCLUSIVE        0x00000010  /* VFS only */
520#define SQLITE_OPEN_AUTOPROXY        0x00000020  /* VFS only */
521#define SQLITE_OPEN_URI              0x00000040  /* Ok for sqlite3_open_v2() */
522#define SQLITE_OPEN_MEMORY           0x00000080  /* Ok for sqlite3_open_v2() */
523#define SQLITE_OPEN_MAIN_DB          0x00000100  /* VFS only */
524#define SQLITE_OPEN_TEMP_DB          0x00000200  /* VFS only */
525#define SQLITE_OPEN_TRANSIENT_DB     0x00000400  /* VFS only */
526#define SQLITE_OPEN_MAIN_JOURNAL     0x00000800  /* VFS only */
527#define SQLITE_OPEN_TEMP_JOURNAL     0x00001000  /* VFS only */
528#define SQLITE_OPEN_SUBJOURNAL       0x00002000  /* VFS only */
529#define SQLITE_OPEN_MASTER_JOURNAL   0x00004000  /* VFS only */
530#define SQLITE_OPEN_NOMUTEX          0x00008000  /* Ok for sqlite3_open_v2() */
531#define SQLITE_OPEN_FULLMUTEX        0x00010000  /* Ok for sqlite3_open_v2() */
532#define SQLITE_OPEN_SHAREDCACHE      0x00020000  /* Ok for sqlite3_open_v2() */
533#define SQLITE_OPEN_PRIVATECACHE     0x00040000  /* Ok for sqlite3_open_v2() */
534#define SQLITE_OPEN_WAL              0x00080000  /* VFS only */
535
536/* Reserved:                         0x00F00000 */
537
538/*
539** CAPI3REF: Device Characteristics
540**
541** The xDeviceCharacteristics method of the [sqlite3_io_methods]
542** object returns an integer which is a vector of these
543** bit values expressing I/O characteristics of the mass storage
544** device that holds the file that the [sqlite3_io_methods]
545** refers to.
546**
547** The SQLITE_IOCAP_ATOMIC property means that all writes of
548** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
549** mean that writes of blocks that are nnn bytes in size and
550** are aligned to an address which is an integer multiple of
551** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
552** that when data is appended to a file, the data is appended
553** first then the size of the file is extended, never the other
554** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
555** information is written to disk in the same order as calls
556** to xWrite().  The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
557** after reboot following a crash or power loss, the only bytes in a
558** file that were written at the application level might have changed
559** and that adjacent bytes, even bytes within the same sector are
560** guaranteed to be unchanged.  The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN
561** flag indicate that a file cannot be deleted when open.  The
562** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on
563** read-only media and cannot be changed even by processes with
564** elevated privileges.
565*/
566#define SQLITE_IOCAP_ATOMIC                 0x00000001
567#define SQLITE_IOCAP_ATOMIC512              0x00000002
568#define SQLITE_IOCAP_ATOMIC1K               0x00000004
569#define SQLITE_IOCAP_ATOMIC2K               0x00000008
570#define SQLITE_IOCAP_ATOMIC4K               0x00000010
571#define SQLITE_IOCAP_ATOMIC8K               0x00000020
572#define SQLITE_IOCAP_ATOMIC16K              0x00000040
573#define SQLITE_IOCAP_ATOMIC32K              0x00000080
574#define SQLITE_IOCAP_ATOMIC64K              0x00000100
575#define SQLITE_IOCAP_SAFE_APPEND            0x00000200
576#define SQLITE_IOCAP_SEQUENTIAL             0x00000400
577#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN  0x00000800
578#define SQLITE_IOCAP_POWERSAFE_OVERWRITE    0x00001000
579#define SQLITE_IOCAP_IMMUTABLE              0x00002000
580
581/*
582** CAPI3REF: File Locking Levels
583**
584** SQLite uses one of these integer values as the second
585** argument to calls it makes to the xLock() and xUnlock() methods
586** of an [sqlite3_io_methods] object.
587*/
588#define SQLITE_LOCK_NONE          0
589#define SQLITE_LOCK_SHARED        1
590#define SQLITE_LOCK_RESERVED      2
591#define SQLITE_LOCK_PENDING       3
592#define SQLITE_LOCK_EXCLUSIVE     4
593
594/*
595** CAPI3REF: Synchronization Type Flags
596**
597** When SQLite invokes the xSync() method of an
598** [sqlite3_io_methods] object it uses a combination of
599** these integer values as the second argument.
600**
601** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
602** sync operation only needs to flush data to mass storage.  Inode
603** information need not be flushed. If the lower four bits of the flag
604** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
605** If the lower four bits equal SQLITE_SYNC_FULL, that means
606** to use Mac OS X style fullsync instead of fsync().
607**
608** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
609** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
610** settings.  The [synchronous pragma] determines when calls to the
611** xSync VFS method occur and applies uniformly across all platforms.
612** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
613** energetic or rigorous or forceful the sync operations are and
614** only make a difference on Mac OSX for the default SQLite code.
615** (Third-party VFS implementations might also make the distinction
616** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
617** operating systems natively supported by SQLite, only Mac OSX
618** cares about the difference.)
619*/
620#define SQLITE_SYNC_NORMAL        0x00002
621#define SQLITE_SYNC_FULL          0x00003
622#define SQLITE_SYNC_DATAONLY      0x00010
623
624/*
625** CAPI3REF: OS Interface Open File Handle
626**
627** An [sqlite3_file] object represents an open file in the
628** [sqlite3_vfs | OS interface layer].  Individual OS interface
629** implementations will
630** want to subclass this object by appending additional fields
631** for their own use.  The pMethods entry is a pointer to an
632** [sqlite3_io_methods] object that defines methods for performing
633** I/O operations on the open file.
634*/
635typedef struct sqlite3_file sqlite3_file;
636struct sqlite3_file {
637  const struct sqlite3_io_methods *pMethods;  /* Methods for an open file */
638};
639
640/*
641** CAPI3REF: OS Interface File Virtual Methods Object
642**
643** Every file opened by the [sqlite3_vfs.xOpen] method populates an
644** [sqlite3_file] object (or, more commonly, a subclass of the
645** [sqlite3_file] object) with a pointer to an instance of this object.
646** This object defines the methods used to perform various operations
647** against the open file represented by the [sqlite3_file] object.
648**
649** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element
650** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
651** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed.  The
652** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
653** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
654** to NULL.
655**
656** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
657** [SQLITE_SYNC_FULL].  The first choice is the normal fsync().
658** The second choice is a Mac OS X style fullsync.  The [SQLITE_SYNC_DATAONLY]
659** flag may be ORed in to indicate that only the data of the file
660** and not its inode needs to be synced.
661**
662** The integer values to xLock() and xUnlock() are one of
663** <ul>
664** <li> [SQLITE_LOCK_NONE],
665** <li> [SQLITE_LOCK_SHARED],
666** <li> [SQLITE_LOCK_RESERVED],
667** <li> [SQLITE_LOCK_PENDING], or
668** <li> [SQLITE_LOCK_EXCLUSIVE].
669** </ul>
670** xLock() increases the lock. xUnlock() decreases the lock.
671** The xCheckReservedLock() method checks whether any database connection,
672** either in this process or in some other process, is holding a RESERVED,
673** PENDING, or EXCLUSIVE lock on the file.  It returns true
674** if such a lock exists and false otherwise.
675**
676** The xFileControl() method is a generic interface that allows custom
677** VFS implementations to directly control an open file using the
678** [sqlite3_file_control()] interface.  The second "op" argument is an
679** integer opcode.  The third argument is a generic pointer intended to
680** point to a structure that may contain arguments or space in which to
681** write return values.  Potential uses for xFileControl() might be
682** functions to enable blocking locks with timeouts, to change the
683** locking strategy (for example to use dot-file locks), to inquire
684** about the status of a lock, or to break stale locks.  The SQLite
685** core reserves all opcodes less than 100 for its own use.
686** A [file control opcodes | list of opcodes] less than 100 is available.
687** Applications that define a custom xFileControl method should use opcodes
688** greater than 100 to avoid conflicts.  VFS implementations should
689** return [SQLITE_NOTFOUND] for file control opcodes that they do not
690** recognize.
691**
692** The xSectorSize() method returns the sector size of the
693** device that underlies the file.  The sector size is the
694** minimum write that can be performed without disturbing
695** other bytes in the file.  The xDeviceCharacteristics()
696** method returns a bit vector describing behaviors of the
697** underlying device:
698**
699** <ul>
700** <li> [SQLITE_IOCAP_ATOMIC]
701** <li> [SQLITE_IOCAP_ATOMIC512]
702** <li> [SQLITE_IOCAP_ATOMIC1K]
703** <li> [SQLITE_IOCAP_ATOMIC2K]
704** <li> [SQLITE_IOCAP_ATOMIC4K]
705** <li> [SQLITE_IOCAP_ATOMIC8K]
706** <li> [SQLITE_IOCAP_ATOMIC16K]
707** <li> [SQLITE_IOCAP_ATOMIC32K]
708** <li> [SQLITE_IOCAP_ATOMIC64K]
709** <li> [SQLITE_IOCAP_SAFE_APPEND]
710** <li> [SQLITE_IOCAP_SEQUENTIAL]
711** </ul>
712**
713** The SQLITE_IOCAP_ATOMIC property means that all writes of
714** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
715** mean that writes of blocks that are nnn bytes in size and
716** are aligned to an address which is an integer multiple of
717** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
718** that when data is appended to a file, the data is appended
719** first then the size of the file is extended, never the other
720** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
721** information is written to disk in the same order as calls
722** to xWrite().
723**
724** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
725** in the unread portions of the buffer with zeros.  A VFS that
726** fails to zero-fill short reads might seem to work.  However,
727** failure to zero-fill short reads will eventually lead to
728** database corruption.
729*/
730typedef struct sqlite3_io_methods sqlite3_io_methods;
731struct sqlite3_io_methods {
732  int iVersion;
733  int (*xClose)(sqlite3_file*);
734  int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
735  int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
736  int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
737  int (*xSync)(sqlite3_file*, int flags);
738  int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
739  int (*xLock)(sqlite3_file*, int);
740  int (*xUnlock)(sqlite3_file*, int);
741  int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
742  int (*xFileControl)(sqlite3_file*, int op, void *pArg);
743  int (*xSectorSize)(sqlite3_file*);
744  int (*xDeviceCharacteristics)(sqlite3_file*);
745  /* Methods above are valid for version 1 */
746  int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
747  int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
748  void (*xShmBarrier)(sqlite3_file*);
749  int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
750  /* Methods above are valid for version 2 */
751  int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp);
752  int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p);
753  /* Methods above are valid for version 3 */
754  /* Additional methods may be added in future releases */
755};
756
757/*
758** CAPI3REF: Standard File Control Opcodes
759** KEYWORDS: {file control opcodes} {file control opcode}
760**
761** These integer constants are opcodes for the xFileControl method
762** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
763** interface.
764**
765** <ul>
766** <li>[[SQLITE_FCNTL_LOCKSTATE]]
767** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging.  This
768** opcode causes the xFileControl method to write the current state of
769** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
770** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
771** into an integer that the pArg argument points to. This capability
772** is used during testing and is only available when the SQLITE_TEST
773** compile-time option is used.
774**
775** <li>[[SQLITE_FCNTL_SIZE_HINT]]
776** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
777** layer a hint of how large the database file will grow to be during the
778** current transaction.  This hint is not guaranteed to be accurate but it
779** is often close.  The underlying VFS might choose to preallocate database
780** file space based on this hint in order to help writes to the database
781** file run faster.
782**
783** <li>[[SQLITE_FCNTL_CHUNK_SIZE]]
784** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
785** extends and truncates the database file in chunks of a size specified
786** by the user. The fourth argument to [sqlite3_file_control()] should
787** point to an integer (type int) containing the new chunk-size to use
788** for the nominated database. Allocating database file space in large
789** chunks (say 1MB at a time), may reduce file-system fragmentation and
790** improve performance on some systems.
791**
792** <li>[[SQLITE_FCNTL_FILE_POINTER]]
793** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
794** to the [sqlite3_file] object associated with a particular database
795** connection.  See the [sqlite3_file_control()] documentation for
796** additional information.
797**
798** <li>[[SQLITE_FCNTL_SYNC_OMITTED]]
799** No longer in use.
800**
801** <li>[[SQLITE_FCNTL_SYNC]]
802** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and
803** sent to the VFS immediately before the xSync method is invoked on a
804** database file descriptor. Or, if the xSync method is not invoked
805** because the user has configured SQLite with
806** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place
807** of the xSync method. In most cases, the pointer argument passed with
808** this file-control is NULL. However, if the database file is being synced
809** as part of a multi-database commit, the argument points to a nul-terminated
810** string containing the transactions master-journal file name. VFSes that
811** do not need this signal should silently ignore this opcode. Applications
812** should not call [sqlite3_file_control()] with this opcode as doing so may
813** disrupt the operation of the specialized VFSes that do require it.
814**
815** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]]
816** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite
817** and sent to the VFS after a transaction has been committed immediately
818** but before the database is unlocked. VFSes that do not need this signal
819** should silently ignore this opcode. Applications should not call
820** [sqlite3_file_control()] with this opcode as doing so may disrupt the
821** operation of the specialized VFSes that do require it.
822**
823** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]]
824** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
825** retry counts and intervals for certain disk I/O operations for the
826** windows [VFS] in order to provide robustness in the presence of
827** anti-virus programs.  By default, the windows VFS will retry file read,
828** file write, and file delete operations up to 10 times, with a delay
829** of 25 milliseconds before the first retry and with the delay increasing
830** by an additional 25 milliseconds with each subsequent retry.  This
831** opcode allows these two values (10 retries and 25 milliseconds of delay)
832** to be adjusted.  The values are changed for all database connections
833** within the same process.  The argument is a pointer to an array of two
834** integers where the first integer i the new retry count and the second
835** integer is the delay.  If either integer is negative, then the setting
836** is not changed but instead the prior value of that setting is written
837** into the array entry, allowing the current retry settings to be
838** interrogated.  The zDbName parameter is ignored.
839**
840** <li>[[SQLITE_FCNTL_PERSIST_WAL]]
841** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
842** persistent [WAL | Write Ahead Log] setting.  By default, the auxiliary
843** write ahead log and shared memory files used for transaction control
844** are automatically deleted when the latest connection to the database
845** closes.  Setting persistent WAL mode causes those files to persist after
846** close.  Persisting the files is useful when other processes that do not
847** have write permission on the directory containing the database file want
848** to read the database file, as the WAL and shared memory files must exist
849** in order for the database to be readable.  The fourth parameter to
850** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
851** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
852** WAL mode.  If the integer is -1, then it is overwritten with the current
853** WAL persistence setting.
854**
855** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]]
856** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
857** persistent "powersafe-overwrite" or "PSOW" setting.  The PSOW setting
858** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
859** xDeviceCharacteristics methods. The fourth parameter to
860** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
861** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
862** mode.  If the integer is -1, then it is overwritten with the current
863** zero-damage mode setting.
864**
865** <li>[[SQLITE_FCNTL_OVERWRITE]]
866** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
867** a write transaction to indicate that, unless it is rolled back for some
868** reason, the entire database file will be overwritten by the current
869** transaction. This is used by VACUUM operations.
870**
871** <li>[[SQLITE_FCNTL_VFSNAME]]
872** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
873** all [VFSes] in the VFS stack.  The names are of all VFS shims and the
874** final bottom-level VFS are written into memory obtained from
875** [sqlite3_malloc()] and the result is stored in the char* variable
876** that the fourth parameter of [sqlite3_file_control()] points to.
877** The caller is responsible for freeing the memory when done.  As with
878** all file-control actions, there is no guarantee that this will actually
879** do anything.  Callers should initialize the char* variable to a NULL
880** pointer in case this file-control is not implemented.  This file-control
881** is intended for diagnostic use only.
882**
883** <li>[[SQLITE_FCNTL_PRAGMA]]
884** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA]
885** file control is sent to the open [sqlite3_file] object corresponding
886** to the database file to which the pragma statement refers. ^The argument
887** to the [SQLITE_FCNTL_PRAGMA] file control is an array of
888** pointers to strings (char**) in which the second element of the array
889** is the name of the pragma and the third element is the argument to the
890** pragma or NULL if the pragma has no argument.  ^The handler for an
891** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element
892** of the char** argument point to a string obtained from [sqlite3_mprintf()]
893** or the equivalent and that string will become the result of the pragma or
894** the error message if the pragma fails. ^If the
895** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal
896** [PRAGMA] processing continues.  ^If the [SQLITE_FCNTL_PRAGMA]
897** file control returns [SQLITE_OK], then the parser assumes that the
898** VFS has handled the PRAGMA itself and the parser generates a no-op
899** prepared statement if result string is NULL, or that returns a copy
900** of the result string if the string is non-NULL.
901** ^If the [SQLITE_FCNTL_PRAGMA] file control returns
902** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means
903** that the VFS encountered an error while handling the [PRAGMA] and the
904** compilation of the PRAGMA fails with an error.  ^The [SQLITE_FCNTL_PRAGMA]
905** file control occurs at the beginning of pragma statement analysis and so
906** it is able to override built-in [PRAGMA] statements.
907**
908** <li>[[SQLITE_FCNTL_BUSYHANDLER]]
909** ^The [SQLITE_FCNTL_BUSYHANDLER]
910** file-control may be invoked by SQLite on the database file handle
911** shortly after it is opened in order to provide a custom VFS with access
912** to the connections busy-handler callback. The argument is of type (void **)
913** - an array of two (void *) values. The first (void *) actually points
914** to a function of type (int (*)(void *)). In order to invoke the connections
915** busy-handler, this function should be invoked with the second (void *) in
916** the array as the only argument. If it returns non-zero, then the operation
917** should be retried. If it returns zero, the custom VFS should abandon the
918** current operation.
919**
920** <li>[[SQLITE_FCNTL_TEMPFILENAME]]
921** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control
922** to have SQLite generate a
923** temporary filename using the same algorithm that is followed to generate
924** temporary filenames for TEMP tables and other internal uses.  The
925** argument should be a char** which will be filled with the filename
926** written into memory obtained from [sqlite3_malloc()].  The caller should
927** invoke [sqlite3_free()] on the result to avoid a memory leak.
928**
929** <li>[[SQLITE_FCNTL_MMAP_SIZE]]
930** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the
931** maximum number of bytes that will be used for memory-mapped I/O.
932** The argument is a pointer to a value of type sqlite3_int64 that
933** is an advisory maximum number of bytes in the file to memory map.  The
934** pointer is overwritten with the old value.  The limit is not changed if
935** the value originally pointed to is negative, and so the current limit
936** can be queried by passing in a pointer to a negative number.  This
937** file-control is used internally to implement [PRAGMA mmap_size].
938**
939** <li>[[SQLITE_FCNTL_TRACE]]
940** The [SQLITE_FCNTL_TRACE] file control provides advisory information
941** to the VFS about what the higher layers of the SQLite stack are doing.
942** This file control is used by some VFS activity tracing [shims].
943** The argument is a zero-terminated string.  Higher layers in the
944** SQLite stack may generate instances of this file control if
945** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled.
946**
947** <li>[[SQLITE_FCNTL_HAS_MOVED]]
948** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a
949** pointer to an integer and it writes a boolean into that integer depending
950** on whether or not the file has been renamed, moved, or deleted since it
951** was first opened.
952**
953** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]]
954** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging.  This
955** opcode causes the xFileControl method to swap the file handle with the one
956** pointed to by the pArg argument.  This capability is used during testing
957** and only needs to be supported when SQLITE_TEST is defined.
958**
959** <li>[[SQLITE_FCNTL_WAL_BLOCK]]
960** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might
961** be advantageous to block on the next WAL lock if the lock is not immediately
962** available.  The WAL subsystem issues this signal during rare
963** circumstances in order to fix a problem with priority inversion.
964** Applications should <em>not</em> use this file-control.
965**
966** <li>[[SQLITE_FCNTL_ZIPVFS]]
967** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other
968** VFS should return SQLITE_NOTFOUND for this opcode.
969**
970** <li>[[SQLITE_FCNTL_RBU]]
971** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by
972** the RBU extension only.  All other VFS should return SQLITE_NOTFOUND for
973** this opcode.
974** </ul>
975*/
976#define SQLITE_FCNTL_LOCKSTATE               1
977#define SQLITE_FCNTL_GET_LOCKPROXYFILE       2
978#define SQLITE_FCNTL_SET_LOCKPROXYFILE       3
979#define SQLITE_FCNTL_LAST_ERRNO              4
980#define SQLITE_FCNTL_SIZE_HINT               5
981#define SQLITE_FCNTL_CHUNK_SIZE              6
982#define SQLITE_FCNTL_FILE_POINTER            7
983#define SQLITE_FCNTL_SYNC_OMITTED            8
984#define SQLITE_FCNTL_WIN32_AV_RETRY          9
985#define SQLITE_FCNTL_PERSIST_WAL            10
986#define SQLITE_FCNTL_OVERWRITE              11
987#define SQLITE_FCNTL_VFSNAME                12
988#define SQLITE_FCNTL_POWERSAFE_OVERWRITE    13
989#define SQLITE_FCNTL_PRAGMA                 14
990#define SQLITE_FCNTL_BUSYHANDLER            15
991#define SQLITE_FCNTL_TEMPFILENAME           16
992#define SQLITE_FCNTL_MMAP_SIZE              18
993#define SQLITE_FCNTL_TRACE                  19
994#define SQLITE_FCNTL_HAS_MOVED              20
995#define SQLITE_FCNTL_SYNC                   21
996#define SQLITE_FCNTL_COMMIT_PHASETWO        22
997#define SQLITE_FCNTL_WIN32_SET_HANDLE       23
998#define SQLITE_FCNTL_WAL_BLOCK              24
999#define SQLITE_FCNTL_ZIPVFS                 25
1000#define SQLITE_FCNTL_RBU                    26
1001
1002/* deprecated names */
1003#define SQLITE_GET_LOCKPROXYFILE      SQLITE_FCNTL_GET_LOCKPROXYFILE
1004#define SQLITE_SET_LOCKPROXYFILE      SQLITE_FCNTL_SET_LOCKPROXYFILE
1005#define SQLITE_LAST_ERRNO             SQLITE_FCNTL_LAST_ERRNO
1006
1007
1008/*
1009** CAPI3REF: Mutex Handle
1010**
1011** The mutex module within SQLite defines [sqlite3_mutex] to be an
1012** abstract type for a mutex object.  The SQLite core never looks
1013** at the internal representation of an [sqlite3_mutex].  It only
1014** deals with pointers to the [sqlite3_mutex] object.
1015**
1016** Mutexes are created using [sqlite3_mutex_alloc()].
1017*/
1018typedef struct sqlite3_mutex sqlite3_mutex;
1019
1020/*
1021** CAPI3REF: OS Interface Object
1022**
1023** An instance of the sqlite3_vfs object defines the interface between
1024** the SQLite core and the underlying operating system.  The "vfs"
1025** in the name of the object stands for "virtual file system".  See
1026** the [VFS | VFS documentation] for further information.
1027**
1028** The value of the iVersion field is initially 1 but may be larger in
1029** future versions of SQLite.  Additional fields may be appended to this
1030** object when the iVersion value is increased.  Note that the structure
1031** of the sqlite3_vfs object changes in the transaction between
1032** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not
1033** modified.
1034**
1035** The szOsFile field is the size of the subclassed [sqlite3_file]
1036** structure used by this VFS.  mxPathname is the maximum length of
1037** a pathname in this VFS.
1038**
1039** Registered sqlite3_vfs objects are kept on a linked list formed by
1040** the pNext pointer.  The [sqlite3_vfs_register()]
1041** and [sqlite3_vfs_unregister()] interfaces manage this list
1042** in a thread-safe way.  The [sqlite3_vfs_find()] interface
1043** searches the list.  Neither the application code nor the VFS
1044** implementation should use the pNext pointer.
1045**
1046** The pNext field is the only field in the sqlite3_vfs
1047** structure that SQLite will ever modify.  SQLite will only access
1048** or modify this field while holding a particular static mutex.
1049** The application should never modify anything within the sqlite3_vfs
1050** object once the object has been registered.
1051**
1052** The zName field holds the name of the VFS module.  The name must
1053** be unique across all VFS modules.
1054**
1055** [[sqlite3_vfs.xOpen]]
1056** ^SQLite guarantees that the zFilename parameter to xOpen
1057** is either a NULL pointer or string obtained
1058** from xFullPathname() with an optional suffix added.
1059** ^If a suffix is added to the zFilename parameter, it will
1060** consist of a single "-" character followed by no more than
1061** 11 alphanumeric and/or "-" characters.
1062** ^SQLite further guarantees that
1063** the string will be valid and unchanged until xClose() is
1064** called. Because of the previous sentence,
1065** the [sqlite3_file] can safely store a pointer to the
1066** filename if it needs to remember the filename for some reason.
1067** If the zFilename parameter to xOpen is a NULL pointer then xOpen
1068** must invent its own temporary name for the file.  ^Whenever the
1069** xFilename parameter is NULL it will also be the case that the
1070** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
1071**
1072** The flags argument to xOpen() includes all bits set in
1073** the flags argument to [sqlite3_open_v2()].  Or if [sqlite3_open()]
1074** or [sqlite3_open16()] is used, then flags includes at least
1075** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE].
1076** If xOpen() opens a file read-only then it sets *pOutFlags to
1077** include [SQLITE_OPEN_READONLY].  Other bits in *pOutFlags may be set.
1078**
1079** ^(SQLite will also add one of the following flags to the xOpen()
1080** call, depending on the object being opened:
1081**
1082** <ul>
1083** <li>  [SQLITE_OPEN_MAIN_DB]
1084** <li>  [SQLITE_OPEN_MAIN_JOURNAL]
1085** <li>  [SQLITE_OPEN_TEMP_DB]
1086** <li>  [SQLITE_OPEN_TEMP_JOURNAL]
1087** <li>  [SQLITE_OPEN_TRANSIENT_DB]
1088** <li>  [SQLITE_OPEN_SUBJOURNAL]
1089** <li>  [SQLITE_OPEN_MASTER_JOURNAL]
1090** <li>  [SQLITE_OPEN_WAL]
1091** </ul>)^
1092**
1093** The file I/O implementation can use the object type flags to
1094** change the way it deals with files.  For example, an application
1095** that does not care about crash recovery or rollback might make
1096** the open of a journal file a no-op.  Writes to this journal would
1097** also be no-ops, and any attempt to read the journal would return
1098** SQLITE_IOERR.  Or the implementation might recognize that a database
1099** file will be doing page-aligned sector reads and writes in a random
1100** order and set up its I/O subsystem accordingly.
1101**
1102** SQLite might also add one of the following flags to the xOpen method:
1103**
1104** <ul>
1105** <li> [SQLITE_OPEN_DELETEONCLOSE]
1106** <li> [SQLITE_OPEN_EXCLUSIVE]
1107** </ul>
1108**
1109** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
1110** deleted when it is closed.  ^The [SQLITE_OPEN_DELETEONCLOSE]
1111** will be set for TEMP databases and their journals, transient
1112** databases, and subjournals.
1113**
1114** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
1115** with the [SQLITE_OPEN_CREATE] flag, which are both directly
1116** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
1117** API.  The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
1118** SQLITE_OPEN_CREATE, is used to indicate that file should always
1119** be created, and that it is an error if it already exists.
1120** It is <i>not</i> used to indicate the file should be opened
1121** for exclusive access.
1122**
1123** ^At least szOsFile bytes of memory are allocated by SQLite
1124** to hold the  [sqlite3_file] structure passed as the third
1125** argument to xOpen.  The xOpen method does not have to
1126** allocate the structure; it should just fill it in.  Note that
1127** the xOpen method must set the sqlite3_file.pMethods to either
1128** a valid [sqlite3_io_methods] object or to NULL.  xOpen must do
1129** this even if the open fails.  SQLite expects that the sqlite3_file.pMethods
1130** element will be valid after xOpen returns regardless of the success
1131** or failure of the xOpen call.
1132**
1133** [[sqlite3_vfs.xAccess]]
1134** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
1135** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
1136** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
1137** to test whether a file is at least readable.   The file can be a
1138** directory.
1139**
1140** ^SQLite will always allocate at least mxPathname+1 bytes for the
1141** output buffer xFullPathname.  The exact size of the output buffer
1142** is also passed as a parameter to both  methods. If the output buffer
1143** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
1144** handled as a fatal error by SQLite, vfs implementations should endeavor
1145** to prevent this by setting mxPathname to a sufficiently large value.
1146**
1147** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
1148** interfaces are not strictly a part of the filesystem, but they are
1149** included in the VFS structure for completeness.
1150** The xRandomness() function attempts to return nBytes bytes
1151** of good-quality randomness into zOut.  The return value is
1152** the actual number of bytes of randomness obtained.
1153** The xSleep() method causes the calling thread to sleep for at
1154** least the number of microseconds given.  ^The xCurrentTime()
1155** method returns a Julian Day Number for the current date and time as
1156** a floating point value.
1157** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
1158** Day Number multiplied by 86400000 (the number of milliseconds in
1159** a 24-hour day).
1160** ^SQLite will use the xCurrentTimeInt64() method to get the current
1161** date and time if that method is available (if iVersion is 2 or
1162** greater and the function pointer is not NULL) and will fall back
1163** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
1164**
1165** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
1166** are not used by the SQLite core.  These optional interfaces are provided
1167** by some VFSes to facilitate testing of the VFS code. By overriding
1168** system calls with functions under its control, a test program can
1169** simulate faults and error conditions that would otherwise be difficult
1170** or impossible to induce.  The set of system calls that can be overridden
1171** varies from one VFS to another, and from one version of the same VFS to the
1172** next.  Applications that use these interfaces must be prepared for any
1173** or all of these interfaces to be NULL or for their behavior to change
1174** from one release to the next.  Applications must not attempt to access
1175** any of these methods if the iVersion of the VFS is less than 3.
1176*/
1177typedef struct sqlite3_vfs sqlite3_vfs;
1178typedef void (*sqlite3_syscall_ptr)(void);
1179struct sqlite3_vfs {
1180  int iVersion;            /* Structure version number (currently 3) */
1181  int szOsFile;            /* Size of subclassed sqlite3_file */
1182  int mxPathname;          /* Maximum file pathname length */
1183  sqlite3_vfs *pNext;      /* Next registered VFS */
1184  const char *zName;       /* Name of this virtual file system */
1185  void *pAppData;          /* Pointer to application-specific data */
1186  int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
1187               int flags, int *pOutFlags);
1188  int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
1189  int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
1190  int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
1191  void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
1192  void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
1193  void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
1194  void (*xDlClose)(sqlite3_vfs*, void*);
1195  int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
1196  int (*xSleep)(sqlite3_vfs*, int microseconds);
1197  int (*xCurrentTime)(sqlite3_vfs*, double*);
1198  int (*xGetLastError)(sqlite3_vfs*, int, char *);
1199  /*
1200  ** The methods above are in version 1 of the sqlite_vfs object
1201  ** definition.  Those that follow are added in version 2 or later
1202  */
1203  int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
1204  /*
1205  ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
1206  ** Those below are for version 3 and greater.
1207  */
1208  int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
1209  sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
1210  const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
1211  /*
1212  ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
1213  ** New fields may be appended in figure versions.  The iVersion
1214  ** value will increment whenever this happens.
1215  */
1216};
1217
1218/*
1219** CAPI3REF: Flags for the xAccess VFS method
1220**
1221** These integer constants can be used as the third parameter to
1222** the xAccess method of an [sqlite3_vfs] object.  They determine
1223** what kind of permissions the xAccess method is looking for.
1224** With SQLITE_ACCESS_EXISTS, the xAccess method
1225** simply checks whether the file exists.
1226** With SQLITE_ACCESS_READWRITE, the xAccess method
1227** checks whether the named directory is both readable and writable
1228** (in other words, if files can be added, removed, and renamed within
1229** the directory).
1230** The SQLITE_ACCESS_READWRITE constant is currently used only by the
1231** [temp_store_directory pragma], though this could change in a future
1232** release of SQLite.
1233** With SQLITE_ACCESS_READ, the xAccess method
1234** checks whether the file is readable.  The SQLITE_ACCESS_READ constant is
1235** currently unused, though it might be used in a future release of
1236** SQLite.
1237*/
1238#define SQLITE_ACCESS_EXISTS    0
1239#define SQLITE_ACCESS_READWRITE 1   /* Used by PRAGMA temp_store_directory */
1240#define SQLITE_ACCESS_READ      2   /* Unused */
1241
1242/*
1243** CAPI3REF: Flags for the xShmLock VFS method
1244**
1245** These integer constants define the various locking operations
1246** allowed by the xShmLock method of [sqlite3_io_methods].  The
1247** following are the only legal combinations of flags to the
1248** xShmLock method:
1249**
1250** <ul>
1251** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
1252** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
1253** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
1254** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
1255** </ul>
1256**
1257** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
1258** was given on the corresponding lock.
1259**
1260** The xShmLock method can transition between unlocked and SHARED or
1261** between unlocked and EXCLUSIVE.  It cannot transition between SHARED
1262** and EXCLUSIVE.
1263*/
1264#define SQLITE_SHM_UNLOCK       1
1265#define SQLITE_SHM_LOCK         2
1266#define SQLITE_SHM_SHARED       4
1267#define SQLITE_SHM_EXCLUSIVE    8
1268
1269/*
1270** CAPI3REF: Maximum xShmLock index
1271**
1272** The xShmLock method on [sqlite3_io_methods] may use values
1273** between 0 and this upper bound as its "offset" argument.
1274** The SQLite core will never attempt to acquire or release a
1275** lock outside of this range
1276*/
1277#define SQLITE_SHM_NLOCK        8
1278
1279
1280/*
1281** CAPI3REF: Initialize The SQLite Library
1282**
1283** ^The sqlite3_initialize() routine initializes the
1284** SQLite library.  ^The sqlite3_shutdown() routine
1285** deallocates any resources that were allocated by sqlite3_initialize().
1286** These routines are designed to aid in process initialization and
1287** shutdown on embedded systems.  Workstation applications using
1288** SQLite normally do not need to invoke either of these routines.
1289**
1290** A call to sqlite3_initialize() is an "effective" call if it is
1291** the first time sqlite3_initialize() is invoked during the lifetime of
1292** the process, or if it is the first time sqlite3_initialize() is invoked
1293** following a call to sqlite3_shutdown().  ^(Only an effective call
1294** of sqlite3_initialize() does any initialization.  All other calls
1295** are harmless no-ops.)^
1296**
1297** A call to sqlite3_shutdown() is an "effective" call if it is the first
1298** call to sqlite3_shutdown() since the last sqlite3_initialize().  ^(Only
1299** an effective call to sqlite3_shutdown() does any deinitialization.
1300** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
1301**
1302** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
1303** is not.  The sqlite3_shutdown() interface must only be called from a
1304** single thread.  All open [database connections] must be closed and all
1305** other SQLite resources must be deallocated prior to invoking
1306** sqlite3_shutdown().
1307**
1308** Among other things, ^sqlite3_initialize() will invoke
1309** sqlite3_os_init().  Similarly, ^sqlite3_shutdown()
1310** will invoke sqlite3_os_end().
1311**
1312** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
1313** ^If for some reason, sqlite3_initialize() is unable to initialize
1314** the library (perhaps it is unable to allocate a needed resource such
1315** as a mutex) it returns an [error code] other than [SQLITE_OK].
1316**
1317** ^The sqlite3_initialize() routine is called internally by many other
1318** SQLite interfaces so that an application usually does not need to
1319** invoke sqlite3_initialize() directly.  For example, [sqlite3_open()]
1320** calls sqlite3_initialize() so the SQLite library will be automatically
1321** initialized when [sqlite3_open()] is called if it has not be initialized
1322** already.  ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
1323** compile-time option, then the automatic calls to sqlite3_initialize()
1324** are omitted and the application must call sqlite3_initialize() directly
1325** prior to using any other SQLite interface.  For maximum portability,
1326** it is recommended that applications always invoke sqlite3_initialize()
1327** directly prior to using any other SQLite interface.  Future releases
1328** of SQLite may require this.  In other words, the behavior exhibited
1329** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
1330** default behavior in some future release of SQLite.
1331**
1332** The sqlite3_os_init() routine does operating-system specific
1333** initialization of the SQLite library.  The sqlite3_os_end()
1334** routine undoes the effect of sqlite3_os_init().  Typical tasks
1335** performed by these routines include allocation or deallocation
1336** of static resources, initialization of global variables,
1337** setting up a default [sqlite3_vfs] module, or setting up
1338** a default configuration using [sqlite3_config()].
1339**
1340** The application should never invoke either sqlite3_os_init()
1341** or sqlite3_os_end() directly.  The application should only invoke
1342** sqlite3_initialize() and sqlite3_shutdown().  The sqlite3_os_init()
1343** interface is called automatically by sqlite3_initialize() and
1344** sqlite3_os_end() is called by sqlite3_shutdown().  Appropriate
1345** implementations for sqlite3_os_init() and sqlite3_os_end()
1346** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
1347** When [custom builds | built for other platforms]
1348** (using the [SQLITE_OS_OTHER=1] compile-time
1349** option) the application must supply a suitable implementation for
1350** sqlite3_os_init() and sqlite3_os_end().  An application-supplied
1351** implementation of sqlite3_os_init() or sqlite3_os_end()
1352** must return [SQLITE_OK] on success and some other [error code] upon
1353** failure.
1354*/
1355SQLITE_API int SQLITE_STDCALL sqlite3_initialize(void);
1356SQLITE_API int SQLITE_STDCALL sqlite3_shutdown(void);
1357SQLITE_API int SQLITE_STDCALL sqlite3_os_init(void);
1358SQLITE_API int SQLITE_STDCALL sqlite3_os_end(void);
1359
1360/*
1361** CAPI3REF: Configuring The SQLite Library
1362**
1363** The sqlite3_config() interface is used to make global configuration
1364** changes to SQLite in order to tune SQLite to the specific needs of
1365** the application.  The default configuration is recommended for most
1366** applications and so this routine is usually not necessary.  It is
1367** provided to support rare applications with unusual needs.
1368**
1369** The sqlite3_config() interface is not threadsafe.  The application
1370** must insure that no other SQLite interfaces are invoked by other
1371** threads while sqlite3_config() is running.  Furthermore, sqlite3_config()
1372** may only be invoked prior to library initialization using
1373** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
1374** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
1375** [sqlite3_shutdown()] then it will return SQLITE_MISUSE.
1376** Note, however, that ^sqlite3_config() can be called as part of the
1377** implementation of an application-defined [sqlite3_os_init()].
1378**
1379** The first argument to sqlite3_config() is an integer
1380** [configuration option] that determines
1381** what property of SQLite is to be configured.  Subsequent arguments
1382** vary depending on the [configuration option]
1383** in the first argument.
1384**
1385** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
1386** ^If the option is unknown or SQLite is unable to set the option
1387** then this routine returns a non-zero [error code].
1388*/
1389SQLITE_API int SQLITE_CDECL sqlite3_config(int, ...);
1390
1391/*
1392** CAPI3REF: Configure database connections
1393** METHOD: sqlite3
1394**
1395** The sqlite3_db_config() interface is used to make configuration
1396** changes to a [database connection].  The interface is similar to
1397** [sqlite3_config()] except that the changes apply to a single
1398** [database connection] (specified in the first argument).
1399**
1400** The second argument to sqlite3_db_config(D,V,...)  is the
1401** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code
1402** that indicates what aspect of the [database connection] is being configured.
1403** Subsequent arguments vary depending on the configuration verb.
1404**
1405** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
1406** the call is considered successful.
1407*/
1408SQLITE_API int SQLITE_CDECL sqlite3_db_config(sqlite3*, int op, ...);
1409
1410/*
1411** CAPI3REF: Memory Allocation Routines
1412**
1413** An instance of this object defines the interface between SQLite
1414** and low-level memory allocation routines.
1415**
1416** This object is used in only one place in the SQLite interface.
1417** A pointer to an instance of this object is the argument to
1418** [sqlite3_config()] when the configuration option is
1419** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].
1420** By creating an instance of this object
1421** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
1422** during configuration, an application can specify an alternative
1423** memory allocation subsystem for SQLite to use for all of its
1424** dynamic memory needs.
1425**
1426** Note that SQLite comes with several [built-in memory allocators]
1427** that are perfectly adequate for the overwhelming majority of applications
1428** and that this object is only useful to a tiny minority of applications
1429** with specialized memory allocation requirements.  This object is
1430** also used during testing of SQLite in order to specify an alternative
1431** memory allocator that simulates memory out-of-memory conditions in
1432** order to verify that SQLite recovers gracefully from such
1433** conditions.
1434**
1435** The xMalloc, xRealloc, and xFree methods must work like the
1436** malloc(), realloc() and free() functions from the standard C library.
1437** ^SQLite guarantees that the second argument to
1438** xRealloc is always a value returned by a prior call to xRoundup.
1439**
1440** xSize should return the allocated size of a memory allocation
1441** previously obtained from xMalloc or xRealloc.  The allocated size
1442** is always at least as big as the requested size but may be larger.
1443**
1444** The xRoundup method returns what would be the allocated size of
1445** a memory allocation given a particular requested size.  Most memory
1446** allocators round up memory allocations at least to the next multiple
1447** of 8.  Some allocators round up to a larger multiple or to a power of 2.
1448** Every memory allocation request coming in through [sqlite3_malloc()]
1449** or [sqlite3_realloc()] first calls xRoundup.  If xRoundup returns 0,
1450** that causes the corresponding memory allocation to fail.
1451**
1452** The xInit method initializes the memory allocator.  For example,
1453** it might allocate any require mutexes or initialize internal data
1454** structures.  The xShutdown method is invoked (indirectly) by
1455** [sqlite3_shutdown()] and should deallocate any resources acquired
1456** by xInit.  The pAppData pointer is used as the only parameter to
1457** xInit and xShutdown.
1458**
1459** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes
1460** the xInit method, so the xInit method need not be threadsafe.  The
1461** xShutdown method is only called from [sqlite3_shutdown()] so it does
1462** not need to be threadsafe either.  For all other methods, SQLite
1463** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
1464** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
1465** it is by default) and so the methods are automatically serialized.
1466** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
1467** methods must be threadsafe or else make their own arrangements for
1468** serialization.
1469**
1470** SQLite will never invoke xInit() more than once without an intervening
1471** call to xShutdown().
1472*/
1473typedef struct sqlite3_mem_methods sqlite3_mem_methods;
1474struct sqlite3_mem_methods {
1475  void *(*xMalloc)(int);         /* Memory allocation function */
1476  void (*xFree)(void*);          /* Free a prior allocation */
1477  void *(*xRealloc)(void*,int);  /* Resize an allocation */
1478  int (*xSize)(void*);           /* Return the size of an allocation */
1479  int (*xRoundup)(int);          /* Round up request size to allocation size */
1480  int (*xInit)(void*);           /* Initialize the memory allocator */
1481  void (*xShutdown)(void*);      /* Deinitialize the memory allocator */
1482  void *pAppData;                /* Argument to xInit() and xShutdown() */
1483};
1484
1485/*
1486** CAPI3REF: Configuration Options
1487** KEYWORDS: {configuration option}
1488**
1489** These constants are the available integer configuration options that
1490** can be passed as the first argument to the [sqlite3_config()] interface.
1491**
1492** New configuration options may be added in future releases of SQLite.
1493** Existing configuration options might be discontinued.  Applications
1494** should check the return code from [sqlite3_config()] to make sure that
1495** the call worked.  The [sqlite3_config()] interface will return a
1496** non-zero [error code] if a discontinued or unsupported configuration option
1497** is invoked.
1498**
1499** <dl>
1500** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
1501** <dd>There are no arguments to this option.  ^This option sets the
1502** [threading mode] to Single-thread.  In other words, it disables
1503** all mutexing and puts SQLite into a mode where it can only be used
1504** by a single thread.   ^If SQLite is compiled with
1505** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1506** it is not possible to change the [threading mode] from its default
1507** value of Single-thread and so [sqlite3_config()] will return
1508** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
1509** configuration option.</dd>
1510**
1511** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt>
1512** <dd>There are no arguments to this option.  ^This option sets the
1513** [threading mode] to Multi-thread.  In other words, it disables
1514** mutexing on [database connection] and [prepared statement] objects.
1515** The application is responsible for serializing access to
1516** [database connections] and [prepared statements].  But other mutexes
1517** are enabled so that SQLite will be safe to use in a multi-threaded
1518** environment as long as no two threads attempt to use the same
1519** [database connection] at the same time.  ^If SQLite is compiled with
1520** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1521** it is not possible to set the Multi-thread [threading mode] and
1522** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1523** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
1524**
1525** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt>
1526** <dd>There are no arguments to this option.  ^This option sets the
1527** [threading mode] to Serialized. In other words, this option enables
1528** all mutexes including the recursive
1529** mutexes on [database connection] and [prepared statement] objects.
1530** In this mode (which is the default when SQLite is compiled with
1531** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
1532** to [database connections] and [prepared statements] so that the
1533** application is free to use the same [database connection] or the
1534** same [prepared statement] in different threads at the same time.
1535** ^If SQLite is compiled with
1536** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1537** it is not possible to set the Serialized [threading mode] and
1538** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1539** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
1540**
1541** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt>
1542** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is
1543** a pointer to an instance of the [sqlite3_mem_methods] structure.
1544** The argument specifies
1545** alternative low-level memory allocation routines to be used in place of
1546** the memory allocation routines built into SQLite.)^ ^SQLite makes
1547** its own private copy of the content of the [sqlite3_mem_methods] structure
1548** before the [sqlite3_config()] call returns.</dd>
1549**
1550** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt>
1551** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which
1552** is a pointer to an instance of the [sqlite3_mem_methods] structure.
1553** The [sqlite3_mem_methods]
1554** structure is filled with the currently defined memory allocation routines.)^
1555** This option can be used to overload the default memory allocation
1556** routines with a wrapper that simulations memory allocation failure or
1557** tracks memory usage, for example. </dd>
1558**
1559** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt>
1560** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int,
1561** interpreted as a boolean, which enables or disables the collection of
1562** memory allocation statistics. ^(When memory allocation statistics are
1563** disabled, the following SQLite interfaces become non-operational:
1564**   <ul>
1565**   <li> [sqlite3_memory_used()]
1566**   <li> [sqlite3_memory_highwater()]
1567**   <li> [sqlite3_soft_heap_limit64()]
1568**   <li> [sqlite3_status64()]
1569**   </ul>)^
1570** ^Memory allocation statistics are enabled by default unless SQLite is
1571** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
1572** allocation statistics are disabled by default.
1573** </dd>
1574**
1575** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt>
1576** <dd> ^The SQLITE_CONFIG_SCRATCH option specifies a static memory buffer
1577** that SQLite can use for scratch memory.  ^(There are three arguments
1578** to SQLITE_CONFIG_SCRATCH:  A pointer an 8-byte
1579** aligned memory buffer from which the scratch allocations will be
1580** drawn, the size of each scratch allocation (sz),
1581** and the maximum number of scratch allocations (N).)^
1582** The first argument must be a pointer to an 8-byte aligned buffer
1583** of at least sz*N bytes of memory.
1584** ^SQLite will not use more than one scratch buffers per thread.
1585** ^SQLite will never request a scratch buffer that is more than 6
1586** times the database page size.
1587** ^If SQLite needs needs additional
1588** scratch memory beyond what is provided by this configuration option, then
1589** [sqlite3_malloc()] will be used to obtain the memory needed.<p>
1590** ^When the application provides any amount of scratch memory using
1591** SQLITE_CONFIG_SCRATCH, SQLite avoids unnecessary large
1592** [sqlite3_malloc|heap allocations].
1593** This can help [Robson proof|prevent memory allocation failures] due to heap
1594** fragmentation in low-memory embedded systems.
1595** </dd>
1596**
1597** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>
1598** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a static memory buffer
1599** that SQLite can use for the database page cache with the default page
1600** cache implementation.
1601** This configuration should not be used if an application-define page
1602** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2]
1603** configuration option.
1604** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to
1605** 8-byte aligned
1606** memory, the size of each page buffer (sz), and the number of pages (N).
1607** The sz argument should be the size of the largest database page
1608** (a power of two between 512 and 65536) plus some extra bytes for each
1609** page header.  ^The number of extra bytes needed by the page header
1610** can be determined using the [SQLITE_CONFIG_PCACHE_HDRSZ] option
1611** to [sqlite3_config()].
1612** ^It is harmless, apart from the wasted memory,
1613** for the sz parameter to be larger than necessary.  The first
1614** argument should pointer to an 8-byte aligned block of memory that
1615** is at least sz*N bytes of memory, otherwise subsequent behavior is
1616** undefined.
1617** ^SQLite will use the memory provided by the first argument to satisfy its
1618** memory needs for the first N pages that it adds to cache.  ^If additional
1619** page cache memory is needed beyond what is provided by this option, then
1620** SQLite goes to [sqlite3_malloc()] for the additional storage space.</dd>
1621**
1622** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt>
1623** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer
1624** that SQLite will use for all of its dynamic memory allocation needs
1625** beyond those provided for by [SQLITE_CONFIG_SCRATCH] and
1626** [SQLITE_CONFIG_PAGECACHE].
1627** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled
1628** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns
1629** [SQLITE_ERROR] if invoked otherwise.
1630** ^There are three arguments to SQLITE_CONFIG_HEAP:
1631** An 8-byte aligned pointer to the memory,
1632** the number of bytes in the memory buffer, and the minimum allocation size.
1633** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
1634** to using its default memory allocator (the system malloc() implementation),
1635** undoing any prior invocation of [SQLITE_CONFIG_MALLOC].  ^If the
1636** memory pointer is not NULL then the alternative memory
1637** allocator is engaged to handle all of SQLites memory allocation needs.
1638** The first pointer (the memory pointer) must be aligned to an 8-byte
1639** boundary or subsequent behavior of SQLite will be undefined.
1640** The minimum allocation size is capped at 2**12. Reasonable values
1641** for the minimum allocation size are 2**5 through 2**8.</dd>
1642**
1643** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt>
1644** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a
1645** pointer to an instance of the [sqlite3_mutex_methods] structure.
1646** The argument specifies alternative low-level mutex routines to be used
1647** in place the mutex routines built into SQLite.)^  ^SQLite makes a copy of
1648** the content of the [sqlite3_mutex_methods] structure before the call to
1649** [sqlite3_config()] returns. ^If SQLite is compiled with
1650** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1651** the entire mutexing subsystem is omitted from the build and hence calls to
1652** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
1653** return [SQLITE_ERROR].</dd>
1654**
1655** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt>
1656** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which
1657** is a pointer to an instance of the [sqlite3_mutex_methods] structure.  The
1658** [sqlite3_mutex_methods]
1659** structure is filled with the currently defined mutex routines.)^
1660** This option can be used to overload the default mutex allocation
1661** routines with a wrapper used to track mutex usage for performance
1662** profiling or testing, for example.   ^If SQLite is compiled with
1663** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1664** the entire mutexing subsystem is omitted from the build and hence calls to
1665** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
1666** return [SQLITE_ERROR].</dd>
1667**
1668** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt>
1669** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine
1670** the default size of lookaside memory on each [database connection].
1671** The first argument is the
1672** size of each lookaside buffer slot and the second is the number of
1673** slots allocated to each database connection.)^  ^(SQLITE_CONFIG_LOOKASIDE
1674** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
1675** option to [sqlite3_db_config()] can be used to change the lookaside
1676** configuration on individual connections.)^ </dd>
1677**
1678** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt>
1679** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is
1680** a pointer to an [sqlite3_pcache_methods2] object.  This object specifies
1681** the interface to a custom page cache implementation.)^
1682** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd>
1683**
1684** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt>
1685** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which
1686** is a pointer to an [sqlite3_pcache_methods2] object.  SQLite copies of
1687** the current page cache implementation into that object.)^ </dd>
1688**
1689** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>
1690** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite
1691** global [error log].
1692** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
1693** function with a call signature of void(*)(void*,int,const char*),
1694** and a pointer to void. ^If the function pointer is not NULL, it is
1695** invoked by [sqlite3_log()] to process each logging event.  ^If the
1696** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
1697** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
1698** passed through as the first parameter to the application-defined logger
1699** function whenever that function is invoked.  ^The second parameter to
1700** the logger function is a copy of the first parameter to the corresponding
1701** [sqlite3_log()] call and is intended to be a [result code] or an
1702** [extended result code].  ^The third parameter passed to the logger is
1703** log message after formatting via [sqlite3_snprintf()].
1704** The SQLite logging interface is not reentrant; the logger function
1705** supplied by the application must not invoke any SQLite interface.
1706** In a multi-threaded application, the application-defined logger
1707** function must be threadsafe. </dd>
1708**
1709** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI
1710** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int.
1711** If non-zero, then URI handling is globally enabled. If the parameter is zero,
1712** then URI handling is globally disabled.)^ ^If URI handling is globally
1713** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()],
1714** [sqlite3_open16()] or
1715** specified as part of [ATTACH] commands are interpreted as URIs, regardless
1716** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
1717** connection is opened. ^If it is globally disabled, filenames are
1718** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
1719** database connection is opened. ^(By default, URI handling is globally
1720** disabled. The default value may be changed by compiling with the
1721** [SQLITE_USE_URI] symbol defined.)^
1722**
1723** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN
1724** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer
1725** argument which is interpreted as a boolean in order to enable or disable
1726** the use of covering indices for full table scans in the query optimizer.
1727** ^The default setting is determined
1728** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on"
1729** if that compile-time option is omitted.
1730** The ability to disable the use of covering indices for full table scans
1731** is because some incorrectly coded legacy applications might malfunction
1732** when the optimization is enabled.  Providing the ability to
1733** disable the optimization allows the older, buggy application code to work
1734** without change even with newer versions of SQLite.
1735**
1736** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]]
1737** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE
1738** <dd> These options are obsolete and should not be used by new code.
1739** They are retained for backwards compatibility but are now no-ops.
1740** </dd>
1741**
1742** [[SQLITE_CONFIG_SQLLOG]]
1743** <dt>SQLITE_CONFIG_SQLLOG
1744** <dd>This option is only available if sqlite is compiled with the
1745** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should
1746** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int).
1747** The second should be of type (void*). The callback is invoked by the library
1748** in three separate circumstances, identified by the value passed as the
1749** fourth parameter. If the fourth parameter is 0, then the database connection
1750** passed as the second argument has just been opened. The third argument
1751** points to a buffer containing the name of the main database file. If the
1752** fourth parameter is 1, then the SQL statement that the third parameter
1753** points to has just been executed. Or, if the fourth parameter is 2, then
1754** the connection being passed as the second parameter is being closed. The
1755** third parameter is passed NULL In this case.  An example of using this
1756** configuration option can be seen in the "test_sqllog.c" source file in
1757** the canonical SQLite source tree.</dd>
1758**
1759** [[SQLITE_CONFIG_MMAP_SIZE]]
1760** <dt>SQLITE_CONFIG_MMAP_SIZE
1761** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values
1762** that are the default mmap size limit (the default setting for
1763** [PRAGMA mmap_size]) and the maximum allowed mmap size limit.
1764** ^The default setting can be overridden by each database connection using
1765** either the [PRAGMA mmap_size] command, or by using the
1766** [SQLITE_FCNTL_MMAP_SIZE] file control.  ^(The maximum allowed mmap size
1767** will be silently truncated if necessary so that it does not exceed the
1768** compile-time maximum mmap size set by the
1769** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^
1770** ^If either argument to this option is negative, then that argument is
1771** changed to its compile-time default.
1772**
1773** [[SQLITE_CONFIG_WIN32_HEAPSIZE]]
1774** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE
1775** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is
1776** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro
1777** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value
1778** that specifies the maximum size of the created heap.
1779**
1780** [[SQLITE_CONFIG_PCACHE_HDRSZ]]
1781** <dt>SQLITE_CONFIG_PCACHE_HDRSZ
1782** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which
1783** is a pointer to an integer and writes into that integer the number of extra
1784** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE].
1785** The amount of extra space required can change depending on the compiler,
1786** target platform, and SQLite version.
1787**
1788** [[SQLITE_CONFIG_PMASZ]]
1789** <dt>SQLITE_CONFIG_PMASZ
1790** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which
1791** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded
1792** sorter to that integer.  The default minimum PMA Size is set by the
1793** [SQLITE_SORTER_PMASZ] compile-time option.  New threads are launched
1794** to help with sort operations when multithreaded sorting
1795** is enabled (using the [PRAGMA threads] command) and the amount of content
1796** to be sorted exceeds the page size times the minimum of the
1797** [PRAGMA cache_size] setting and this value.
1798** </dl>
1799*/
1800#define SQLITE_CONFIG_SINGLETHREAD  1  /* nil */
1801#define SQLITE_CONFIG_MULTITHREAD   2  /* nil */
1802#define SQLITE_CONFIG_SERIALIZED    3  /* nil */
1803#define SQLITE_CONFIG_MALLOC        4  /* sqlite3_mem_methods* */
1804#define SQLITE_CONFIG_GETMALLOC     5  /* sqlite3_mem_methods* */
1805#define SQLITE_CONFIG_SCRATCH       6  /* void*, int sz, int N */
1806#define SQLITE_CONFIG_PAGECACHE     7  /* void*, int sz, int N */
1807#define SQLITE_CONFIG_HEAP          8  /* void*, int nByte, int min */
1808#define SQLITE_CONFIG_MEMSTATUS     9  /* boolean */
1809#define SQLITE_CONFIG_MUTEX        10  /* sqlite3_mutex_methods* */
1810#define SQLITE_CONFIG_GETMUTEX     11  /* sqlite3_mutex_methods* */
1811/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */
1812#define SQLITE_CONFIG_LOOKASIDE    13  /* int int */
1813#define SQLITE_CONFIG_PCACHE       14  /* no-op */
1814#define SQLITE_CONFIG_GETPCACHE    15  /* no-op */
1815#define SQLITE_CONFIG_LOG          16  /* xFunc, void* */
1816#define SQLITE_CONFIG_URI          17  /* int */
1817#define SQLITE_CONFIG_PCACHE2      18  /* sqlite3_pcache_methods2* */
1818#define SQLITE_CONFIG_GETPCACHE2   19  /* sqlite3_pcache_methods2* */
1819#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20  /* int */
1820#define SQLITE_CONFIG_SQLLOG       21  /* xSqllog, void* */
1821#define SQLITE_CONFIG_MMAP_SIZE    22  /* sqlite3_int64, sqlite3_int64 */
1822#define SQLITE_CONFIG_WIN32_HEAPSIZE      23  /* int nByte */
1823#define SQLITE_CONFIG_PCACHE_HDRSZ        24  /* int *psz */
1824#define SQLITE_CONFIG_PMASZ               25  /* unsigned int szPma */
1825
1826/*
1827** CAPI3REF: Database Connection Configuration Options
1828**
1829** These constants are the available integer configuration options that
1830** can be passed as the second argument to the [sqlite3_db_config()] interface.
1831**
1832** New configuration options may be added in future releases of SQLite.
1833** Existing configuration options might be discontinued.  Applications
1834** should check the return code from [sqlite3_db_config()] to make sure that
1835** the call worked.  ^The [sqlite3_db_config()] interface will return a
1836** non-zero [error code] if a discontinued or unsupported configuration option
1837** is invoked.
1838**
1839** <dl>
1840** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
1841** <dd> ^This option takes three additional arguments that determine the
1842** [lookaside memory allocator] configuration for the [database connection].
1843** ^The first argument (the third parameter to [sqlite3_db_config()] is a
1844** pointer to a memory buffer to use for lookaside memory.
1845** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
1846** may be NULL in which case SQLite will allocate the
1847** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
1848** size of each lookaside buffer slot.  ^The third argument is the number of
1849** slots.  The size of the buffer in the first argument must be greater than
1850** or equal to the product of the second and third arguments.  The buffer
1851** must be aligned to an 8-byte boundary.  ^If the second argument to
1852** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
1853** rounded down to the next smaller multiple of 8.  ^(The lookaside memory
1854** configuration for a database connection can only be changed when that
1855** connection is not currently using lookaside memory, or in other words
1856** when the "current value" returned by
1857** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero.
1858** Any attempt to change the lookaside memory configuration when lookaside
1859** memory is in use leaves the configuration unchanged and returns
1860** [SQLITE_BUSY].)^</dd>
1861**
1862** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
1863** <dd> ^This option is used to enable or disable the enforcement of
1864** [foreign key constraints].  There should be two additional arguments.
1865** The first argument is an integer which is 0 to disable FK enforcement,
1866** positive to enable FK enforcement or negative to leave FK enforcement
1867** unchanged.  The second parameter is a pointer to an integer into which
1868** is written 0 or 1 to indicate whether FK enforcement is off or on
1869** following this call.  The second parameter may be a NULL pointer, in
1870** which case the FK enforcement setting is not reported back. </dd>
1871**
1872** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
1873** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
1874** There should be two additional arguments.
1875** The first argument is an integer which is 0 to disable triggers,
1876** positive to enable triggers or negative to leave the setting unchanged.
1877** The second parameter is a pointer to an integer into which
1878** is written 0 or 1 to indicate whether triggers are disabled or enabled
1879** following this call.  The second parameter may be a NULL pointer, in
1880** which case the trigger setting is not reported back. </dd>
1881**
1882** </dl>
1883*/
1884#define SQLITE_DBCONFIG_LOOKASIDE       1001  /* void* int int */
1885#define SQLITE_DBCONFIG_ENABLE_FKEY     1002  /* int int* */
1886#define SQLITE_DBCONFIG_ENABLE_TRIGGER  1003  /* int int* */
1887
1888
1889/*
1890** CAPI3REF: Enable Or Disable Extended Result Codes
1891** METHOD: sqlite3
1892**
1893** ^The sqlite3_extended_result_codes() routine enables or disables the
1894** [extended result codes] feature of SQLite. ^The extended result
1895** codes are disabled by default for historical compatibility.
1896*/
1897SQLITE_API int SQLITE_STDCALL sqlite3_extended_result_codes(sqlite3*, int onoff);
1898
1899/*
1900** CAPI3REF: Last Insert Rowid
1901** METHOD: sqlite3
1902**
1903** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables)
1904** has a unique 64-bit signed
1905** integer key called the [ROWID | "rowid"]. ^The rowid is always available
1906** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
1907** names are not also used by explicitly declared columns. ^If
1908** the table has a column of type [INTEGER PRIMARY KEY] then that column
1909** is another alias for the rowid.
1910**
1911** ^The sqlite3_last_insert_rowid(D) interface returns the [rowid] of the
1912** most recent successful [INSERT] into a rowid table or [virtual table]
1913** on database connection D.
1914** ^Inserts into [WITHOUT ROWID] tables are not recorded.
1915** ^If no successful [INSERT]s into rowid tables
1916** have ever occurred on the database connection D,
1917** then sqlite3_last_insert_rowid(D) returns zero.
1918**
1919** ^(If an [INSERT] occurs within a trigger or within a [virtual table]
1920** method, then this routine will return the [rowid] of the inserted
1921** row as long as the trigger or virtual table method is running.
1922** But once the trigger or virtual table method ends, the value returned
1923** by this routine reverts to what it was before the trigger or virtual
1924** table method began.)^
1925**
1926** ^An [INSERT] that fails due to a constraint violation is not a
1927** successful [INSERT] and does not change the value returned by this
1928** routine.  ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
1929** and INSERT OR ABORT make no changes to the return value of this
1930** routine when their insertion fails.  ^(When INSERT OR REPLACE
1931** encounters a constraint violation, it does not fail.  The
1932** INSERT continues to completion after deleting rows that caused
1933** the constraint problem so INSERT OR REPLACE will always change
1934** the return value of this interface.)^
1935**
1936** ^For the purposes of this routine, an [INSERT] is considered to
1937** be successful even if it is subsequently rolled back.
1938**
1939** This function is accessible to SQL statements via the
1940** [last_insert_rowid() SQL function].
1941**
1942** If a separate thread performs a new [INSERT] on the same
1943** database connection while the [sqlite3_last_insert_rowid()]
1944** function is running and thus changes the last insert [rowid],
1945** then the value returned by [sqlite3_last_insert_rowid()] is
1946** unpredictable and might not equal either the old or the new
1947** last insert [rowid].
1948*/
1949SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_last_insert_rowid(sqlite3*);
1950
1951/*
1952** CAPI3REF: Count The Number Of Rows Modified
1953** METHOD: sqlite3
1954**
1955** ^This function returns the number of rows modified, inserted or
1956** deleted by the most recently completed INSERT, UPDATE or DELETE
1957** statement on the database connection specified by the only parameter.
1958** ^Executing any other type of SQL statement does not modify the value
1959** returned by this function.
1960**
1961** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are
1962** considered - auxiliary changes caused by [CREATE TRIGGER | triggers],
1963** [foreign key actions] or [REPLACE] constraint resolution are not counted.
1964**
1965** Changes to a view that are intercepted by
1966** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value
1967** returned by sqlite3_changes() immediately after an INSERT, UPDATE or
1968** DELETE statement run on a view is always zero. Only changes made to real
1969** tables are counted.
1970**
1971** Things are more complicated if the sqlite3_changes() function is
1972** executed while a trigger program is running. This may happen if the
1973** program uses the [changes() SQL function], or if some other callback
1974** function invokes sqlite3_changes() directly. Essentially:
1975**
1976** <ul>
1977**   <li> ^(Before entering a trigger program the value returned by
1978**        sqlite3_changes() function is saved. After the trigger program
1979**        has finished, the original value is restored.)^
1980**
1981**   <li> ^(Within a trigger program each INSERT, UPDATE and DELETE
1982**        statement sets the value returned by sqlite3_changes()
1983**        upon completion as normal. Of course, this value will not include
1984**        any changes performed by sub-triggers, as the sqlite3_changes()
1985**        value will be saved and restored after each sub-trigger has run.)^
1986** </ul>
1987**
1988** ^This means that if the changes() SQL function (or similar) is used
1989** by the first INSERT, UPDATE or DELETE statement within a trigger, it
1990** returns the value as set when the calling statement began executing.
1991** ^If it is used by the second or subsequent such statement within a trigger
1992** program, the value returned reflects the number of rows modified by the
1993** previous INSERT, UPDATE or DELETE statement within the same trigger.
1994**
1995** See also the [sqlite3_total_changes()] interface, the
1996** [count_changes pragma], and the [changes() SQL function].
1997**
1998** If a separate thread makes changes on the same database connection
1999** while [sqlite3_changes()] is running then the value returned
2000** is unpredictable and not meaningful.
2001*/
2002SQLITE_API int SQLITE_STDCALL sqlite3_changes(sqlite3*);
2003
2004/*
2005** CAPI3REF: Total Number Of Rows Modified
2006** METHOD: sqlite3
2007**
2008** ^This function returns the total number of rows inserted, modified or
2009** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed
2010** since the database connection was opened, including those executed as
2011** part of trigger programs. ^Executing any other type of SQL statement
2012** does not affect the value returned by sqlite3_total_changes().
2013**
2014** ^Changes made as part of [foreign key actions] are included in the
2015** count, but those made as part of REPLACE constraint resolution are
2016** not. ^Changes to a view that are intercepted by INSTEAD OF triggers
2017** are not counted.
2018**
2019** See also the [sqlite3_changes()] interface, the
2020** [count_changes pragma], and the [total_changes() SQL function].
2021**
2022** If a separate thread makes changes on the same database connection
2023** while [sqlite3_total_changes()] is running then the value
2024** returned is unpredictable and not meaningful.
2025*/
2026SQLITE_API int SQLITE_STDCALL sqlite3_total_changes(sqlite3*);
2027
2028/*
2029** CAPI3REF: Interrupt A Long-Running Query
2030** METHOD: sqlite3
2031**
2032** ^This function causes any pending database operation to abort and
2033** return at its earliest opportunity. This routine is typically
2034** called in response to a user action such as pressing "Cancel"
2035** or Ctrl-C where the user wants a long query operation to halt
2036** immediately.
2037**
2038** ^It is safe to call this routine from a thread different from the
2039** thread that is currently running the database operation.  But it
2040** is not safe to call this routine with a [database connection] that
2041** is closed or might close before sqlite3_interrupt() returns.
2042**
2043** ^If an SQL operation is very nearly finished at the time when
2044** sqlite3_interrupt() is called, then it might not have an opportunity
2045** to be interrupted and might continue to completion.
2046**
2047** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
2048** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
2049** that is inside an explicit transaction, then the entire transaction
2050** will be rolled back automatically.
2051**
2052** ^The sqlite3_interrupt(D) call is in effect until all currently running
2053** SQL statements on [database connection] D complete.  ^Any new SQL statements
2054** that are started after the sqlite3_interrupt() call and before the
2055** running statements reaches zero are interrupted as if they had been
2056** running prior to the sqlite3_interrupt() call.  ^New SQL statements
2057** that are started after the running statement count reaches zero are
2058** not effected by the sqlite3_interrupt().
2059** ^A call to sqlite3_interrupt(D) that occurs when there are no running
2060** SQL statements is a no-op and has no effect on SQL statements
2061** that are started after the sqlite3_interrupt() call returns.
2062**
2063** If the database connection closes while [sqlite3_interrupt()]
2064** is running then bad things will likely happen.
2065*/
2066SQLITE_API void SQLITE_STDCALL sqlite3_interrupt(sqlite3*);
2067
2068/*
2069** CAPI3REF: Determine If An SQL Statement Is Complete
2070**
2071** These routines are useful during command-line input to determine if the
2072** currently entered text seems to form a complete SQL statement or
2073** if additional input is needed before sending the text into
2074** SQLite for parsing.  ^These routines return 1 if the input string
2075** appears to be a complete SQL statement.  ^A statement is judged to be
2076** complete if it ends with a semicolon token and is not a prefix of a
2077** well-formed CREATE TRIGGER statement.  ^Semicolons that are embedded within
2078** string literals or quoted identifier names or comments are not
2079** independent tokens (they are part of the token in which they are
2080** embedded) and thus do not count as a statement terminator.  ^Whitespace
2081** and comments that follow the final semicolon are ignored.
2082**
2083** ^These routines return 0 if the statement is incomplete.  ^If a
2084** memory allocation fails, then SQLITE_NOMEM is returned.
2085**
2086** ^These routines do not parse the SQL statements thus
2087** will not detect syntactically incorrect SQL.
2088**
2089** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior
2090** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
2091** automatically by sqlite3_complete16().  If that initialization fails,
2092** then the return value from sqlite3_complete16() will be non-zero
2093** regardless of whether or not the input SQL is complete.)^
2094**
2095** The input to [sqlite3_complete()] must be a zero-terminated
2096** UTF-8 string.
2097**
2098** The input to [sqlite3_complete16()] must be a zero-terminated
2099** UTF-16 string in native byte order.
2100*/
2101SQLITE_API int SQLITE_STDCALL sqlite3_complete(const char *sql);
2102SQLITE_API int SQLITE_STDCALL sqlite3_complete16(const void *sql);
2103
2104/*
2105** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
2106** KEYWORDS: {busy-handler callback} {busy handler}
2107** METHOD: sqlite3
2108**
2109** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X
2110** that might be invoked with argument P whenever
2111** an attempt is made to access a database table associated with
2112** [database connection] D when another thread
2113** or process has the table locked.
2114** The sqlite3_busy_handler() interface is used to implement
2115** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout].
2116**
2117** ^If the busy callback is NULL, then [SQLITE_BUSY]
2118** is returned immediately upon encountering the lock.  ^If the busy callback
2119** is not NULL, then the callback might be invoked with two arguments.
2120**
2121** ^The first argument to the busy handler is a copy of the void* pointer which
2122** is the third argument to sqlite3_busy_handler().  ^The second argument to
2123** the busy handler callback is the number of times that the busy handler has
2124** been invoked previously for the same locking event.  ^If the
2125** busy callback returns 0, then no additional attempts are made to
2126** access the database and [SQLITE_BUSY] is returned
2127** to the application.
2128** ^If the callback returns non-zero, then another attempt
2129** is made to access the database and the cycle repeats.
2130**
2131** The presence of a busy handler does not guarantee that it will be invoked
2132** when there is lock contention. ^If SQLite determines that invoking the busy
2133** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
2134** to the application instead of invoking the
2135** busy handler.
2136** Consider a scenario where one process is holding a read lock that
2137** it is trying to promote to a reserved lock and
2138** a second process is holding a reserved lock that it is trying
2139** to promote to an exclusive lock.  The first process cannot proceed
2140** because it is blocked by the second and the second process cannot
2141** proceed because it is blocked by the first.  If both processes
2142** invoke the busy handlers, neither will make any progress.  Therefore,
2143** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
2144** will induce the first process to release its read lock and allow
2145** the second process to proceed.
2146**
2147** ^The default busy callback is NULL.
2148**
2149** ^(There can only be a single busy handler defined for each
2150** [database connection].  Setting a new busy handler clears any
2151** previously set handler.)^  ^Note that calling [sqlite3_busy_timeout()]
2152** or evaluating [PRAGMA busy_timeout=N] will change the
2153** busy handler and thus clear any previously set busy handler.
2154**
2155** The busy callback should not take any actions which modify the
2156** database connection that invoked the busy handler.  In other words,
2157** the busy handler is not reentrant.  Any such actions
2158** result in undefined behavior.
2159**
2160** A busy handler must not close the database connection
2161** or [prepared statement] that invoked the busy handler.
2162*/
2163SQLITE_API int SQLITE_STDCALL sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*);
2164
2165/*
2166** CAPI3REF: Set A Busy Timeout
2167** METHOD: sqlite3
2168**
2169** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
2170** for a specified amount of time when a table is locked.  ^The handler
2171** will sleep multiple times until at least "ms" milliseconds of sleeping
2172** have accumulated.  ^After at least "ms" milliseconds of sleeping,
2173** the handler returns 0 which causes [sqlite3_step()] to return
2174** [SQLITE_BUSY].
2175**
2176** ^Calling this routine with an argument less than or equal to zero
2177** turns off all busy handlers.
2178**
2179** ^(There can only be a single busy handler for a particular
2180** [database connection] at any given moment.  If another busy handler
2181** was defined  (using [sqlite3_busy_handler()]) prior to calling
2182** this routine, that other busy handler is cleared.)^
2183**
2184** See also:  [PRAGMA busy_timeout]
2185*/
2186SQLITE_API int SQLITE_STDCALL sqlite3_busy_timeout(sqlite3*, int ms);
2187
2188/*
2189** CAPI3REF: Convenience Routines For Running Queries
2190** METHOD: sqlite3
2191**
2192** This is a legacy interface that is preserved for backwards compatibility.
2193** Use of this interface is not recommended.
2194**
2195** Definition: A <b>result table</b> is memory data structure created by the
2196** [sqlite3_get_table()] interface.  A result table records the
2197** complete query results from one or more queries.
2198**
2199** The table conceptually has a number of rows and columns.  But
2200** these numbers are not part of the result table itself.  These
2201** numbers are obtained separately.  Let N be the number of rows
2202** and M be the number of columns.
2203**
2204** A result table is an array of pointers to zero-terminated UTF-8 strings.
2205** There are (N+1)*M elements in the array.  The first M pointers point
2206** to zero-terminated strings that  contain the names of the columns.
2207** The remaining entries all point to query results.  NULL values result
2208** in NULL pointers.  All other values are in their UTF-8 zero-terminated
2209** string representation as returned by [sqlite3_column_text()].
2210**
2211** A result table might consist of one or more memory allocations.
2212** It is not safe to pass a result table directly to [sqlite3_free()].
2213** A result table should be deallocated using [sqlite3_free_table()].
2214**
2215** ^(As an example of the result table format, suppose a query result
2216** is as follows:
2217**
2218** <blockquote><pre>
2219**        Name        | Age
2220**        -----------------------
2221**        Alice       | 43
2222**        Bob         | 28
2223**        Cindy       | 21
2224** </pre></blockquote>
2225**
2226** There are two column (M==2) and three rows (N==3).  Thus the
2227** result table has 8 entries.  Suppose the result table is stored
2228** in an array names azResult.  Then azResult holds this content:
2229**
2230** <blockquote><pre>
2231**        azResult&#91;0] = "Name";
2232**        azResult&#91;1] = "Age";
2233**        azResult&#91;2] = "Alice";
2234**        azResult&#91;3] = "43";
2235**        azResult&#91;4] = "Bob";
2236**        azResult&#91;5] = "28";
2237**        azResult&#91;6] = "Cindy";
2238**        azResult&#91;7] = "21";
2239** </pre></blockquote>)^
2240**
2241** ^The sqlite3_get_table() function evaluates one or more
2242** semicolon-separated SQL statements in the zero-terminated UTF-8
2243** string of its 2nd parameter and returns a result table to the
2244** pointer given in its 3rd parameter.
2245**
2246** After the application has finished with the result from sqlite3_get_table(),
2247** it must pass the result table pointer to sqlite3_free_table() in order to
2248** release the memory that was malloced.  Because of the way the
2249** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
2250** function must not try to call [sqlite3_free()] directly.  Only
2251** [sqlite3_free_table()] is able to release the memory properly and safely.
2252**
2253** The sqlite3_get_table() interface is implemented as a wrapper around
2254** [sqlite3_exec()].  The sqlite3_get_table() routine does not have access
2255** to any internal data structures of SQLite.  It uses only the public
2256** interface defined here.  As a consequence, errors that occur in the
2257** wrapper layer outside of the internal [sqlite3_exec()] call are not
2258** reflected in subsequent calls to [sqlite3_errcode()] or
2259** [sqlite3_errmsg()].
2260*/
2261SQLITE_API int SQLITE_STDCALL sqlite3_get_table(
2262  sqlite3 *db,          /* An open database */
2263  const char *zSql,     /* SQL to be evaluated */
2264  char ***pazResult,    /* Results of the query */
2265  int *pnRow,           /* Number of result rows written here */
2266  int *pnColumn,        /* Number of result columns written here */
2267  char **pzErrmsg       /* Error msg written here */
2268);
2269SQLITE_API void SQLITE_STDCALL sqlite3_free_table(char **result);
2270
2271/*
2272** CAPI3REF: Formatted String Printing Functions
2273**
2274** These routines are work-alikes of the "printf()" family of functions
2275** from the standard C library.
2276** These routines understand most of the common K&R formatting options,
2277** plus some additional non-standard formats, detailed below.
2278** Note that some of the more obscure formatting options from recent
2279** C-library standards are omitted from this implementation.
2280**
2281** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
2282** results into memory obtained from [sqlite3_malloc()].
2283** The strings returned by these two routines should be
2284** released by [sqlite3_free()].  ^Both routines return a
2285** NULL pointer if [sqlite3_malloc()] is unable to allocate enough
2286** memory to hold the resulting string.
2287**
2288** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
2289** the standard C library.  The result is written into the
2290** buffer supplied as the second parameter whose size is given by
2291** the first parameter. Note that the order of the
2292** first two parameters is reversed from snprintf().)^  This is an
2293** historical accident that cannot be fixed without breaking
2294** backwards compatibility.  ^(Note also that sqlite3_snprintf()
2295** returns a pointer to its buffer instead of the number of
2296** characters actually written into the buffer.)^  We admit that
2297** the number of characters written would be a more useful return
2298** value but we cannot change the implementation of sqlite3_snprintf()
2299** now without breaking compatibility.
2300**
2301** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
2302** guarantees that the buffer is always zero-terminated.  ^The first
2303** parameter "n" is the total size of the buffer, including space for
2304** the zero terminator.  So the longest string that can be completely
2305** written will be n-1 characters.
2306**
2307** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
2308**
2309** These routines all implement some additional formatting
2310** options that are useful for constructing SQL statements.
2311** All of the usual printf() formatting options apply.  In addition, there
2312** is are "%q", "%Q", "%w" and "%z" options.
2313**
2314** ^(The %q option works like %s in that it substitutes a nul-terminated
2315** string from the argument list.  But %q also doubles every '\'' character.
2316** %q is designed for use inside a string literal.)^  By doubling each '\''
2317** character it escapes that character and allows it to be inserted into
2318** the string.
2319**
2320** For example, assume the string variable zText contains text as follows:
2321**
2322** <blockquote><pre>
2323**  char *zText = "It's a happy day!";
2324** </pre></blockquote>
2325**
2326** One can use this text in an SQL statement as follows:
2327**
2328** <blockquote><pre>
2329**  char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText);
2330**  sqlite3_exec(db, zSQL, 0, 0, 0);
2331**  sqlite3_free(zSQL);
2332** </pre></blockquote>
2333**
2334** Because the %q format string is used, the '\'' character in zText
2335** is escaped and the SQL generated is as follows:
2336**
2337** <blockquote><pre>
2338**  INSERT INTO table1 VALUES('It''s a happy day!')
2339** </pre></blockquote>
2340**
2341** This is correct.  Had we used %s instead of %q, the generated SQL
2342** would have looked like this:
2343**
2344** <blockquote><pre>
2345**  INSERT INTO table1 VALUES('It's a happy day!');
2346** </pre></blockquote>
2347**
2348** This second example is an SQL syntax error.  As a general rule you should
2349** always use %q instead of %s when inserting text into a string literal.
2350**
2351** ^(The %Q option works like %q except it also adds single quotes around
2352** the outside of the total string.  Additionally, if the parameter in the
2353** argument list is a NULL pointer, %Q substitutes the text "NULL" (without
2354** single quotes).)^  So, for example, one could say:
2355**
2356** <blockquote><pre>
2357**  char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText);
2358**  sqlite3_exec(db, zSQL, 0, 0, 0);
2359**  sqlite3_free(zSQL);
2360** </pre></blockquote>
2361**
2362** The code above will render a correct SQL statement in the zSQL
2363** variable even if the zText variable is a NULL pointer.
2364**
2365** ^(The "%w" formatting option is like "%q" except that it expects to
2366** be contained within double-quotes instead of single quotes, and it
2367** escapes the double-quote character instead of the single-quote
2368** character.)^  The "%w" formatting option is intended for safely inserting
2369** table and column names into a constructed SQL statement.
2370**
2371** ^(The "%z" formatting option works like "%s" but with the
2372** addition that after the string has been read and copied into
2373** the result, [sqlite3_free()] is called on the input string.)^
2374*/
2375SQLITE_API char *SQLITE_CDECL sqlite3_mprintf(const char*,...);
2376SQLITE_API char *SQLITE_STDCALL sqlite3_vmprintf(const char*, va_list);
2377SQLITE_API char *SQLITE_CDECL sqlite3_snprintf(int,char*,const char*, ...);
2378SQLITE_API char *SQLITE_STDCALL sqlite3_vsnprintf(int,char*,const char*, va_list);
2379
2380/*
2381** CAPI3REF: Memory Allocation Subsystem
2382**
2383** The SQLite core uses these three routines for all of its own
2384** internal memory allocation needs. "Core" in the previous sentence
2385** does not include operating-system specific VFS implementation.  The
2386** Windows VFS uses native malloc() and free() for some operations.
2387**
2388** ^The sqlite3_malloc() routine returns a pointer to a block
2389** of memory at least N bytes in length, where N is the parameter.
2390** ^If sqlite3_malloc() is unable to obtain sufficient free
2391** memory, it returns a NULL pointer.  ^If the parameter N to
2392** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
2393** a NULL pointer.
2394**
2395** ^The sqlite3_malloc64(N) routine works just like
2396** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead
2397** of a signed 32-bit integer.
2398**
2399** ^Calling sqlite3_free() with a pointer previously returned
2400** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
2401** that it might be reused.  ^The sqlite3_free() routine is
2402** a no-op if is called with a NULL pointer.  Passing a NULL pointer
2403** to sqlite3_free() is harmless.  After being freed, memory
2404** should neither be read nor written.  Even reading previously freed
2405** memory might result in a segmentation fault or other severe error.
2406** Memory corruption, a segmentation fault, or other severe error
2407** might result if sqlite3_free() is called with a non-NULL pointer that
2408** was not obtained from sqlite3_malloc() or sqlite3_realloc().
2409**
2410** ^The sqlite3_realloc(X,N) interface attempts to resize a
2411** prior memory allocation X to be at least N bytes.
2412** ^If the X parameter to sqlite3_realloc(X,N)
2413** is a NULL pointer then its behavior is identical to calling
2414** sqlite3_malloc(N).
2415** ^If the N parameter to sqlite3_realloc(X,N) is zero or
2416** negative then the behavior is exactly the same as calling
2417** sqlite3_free(X).
2418** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation
2419** of at least N bytes in size or NULL if insufficient memory is available.
2420** ^If M is the size of the prior allocation, then min(N,M) bytes
2421** of the prior allocation are copied into the beginning of buffer returned
2422** by sqlite3_realloc(X,N) and the prior allocation is freed.
2423** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the
2424** prior allocation is not freed.
2425**
2426** ^The sqlite3_realloc64(X,N) interfaces works the same as
2427** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead
2428** of a 32-bit signed integer.
2429**
2430** ^If X is a memory allocation previously obtained from sqlite3_malloc(),
2431** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then
2432** sqlite3_msize(X) returns the size of that memory allocation in bytes.
2433** ^The value returned by sqlite3_msize(X) might be larger than the number
2434** of bytes requested when X was allocated.  ^If X is a NULL pointer then
2435** sqlite3_msize(X) returns zero.  If X points to something that is not
2436** the beginning of memory allocation, or if it points to a formerly
2437** valid memory allocation that has now been freed, then the behavior
2438** of sqlite3_msize(X) is undefined and possibly harmful.
2439**
2440** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(),
2441** sqlite3_malloc64(), and sqlite3_realloc64()
2442** is always aligned to at least an 8 byte boundary, or to a
2443** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
2444** option is used.
2445**
2446** In SQLite version 3.5.0 and 3.5.1, it was possible to define
2447** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in
2448** implementation of these routines to be omitted.  That capability
2449** is no longer provided.  Only built-in memory allocators can be used.
2450**
2451** Prior to SQLite version 3.7.10, the Windows OS interface layer called
2452** the system malloc() and free() directly when converting
2453** filenames between the UTF-8 encoding used by SQLite
2454** and whatever filename encoding is used by the particular Windows
2455** installation.  Memory allocation errors were detected, but
2456** they were reported back as [SQLITE_CANTOPEN] or
2457** [SQLITE_IOERR] rather than [SQLITE_NOMEM].
2458**
2459** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
2460** must be either NULL or else pointers obtained from a prior
2461** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
2462** not yet been released.
2463**
2464** The application must not read or write any part of
2465** a block of memory after it has been released using
2466** [sqlite3_free()] or [sqlite3_realloc()].
2467*/
2468SQLITE_API void *SQLITE_STDCALL sqlite3_malloc(int);
2469SQLITE_API void *SQLITE_STDCALL sqlite3_malloc64(sqlite3_uint64);
2470SQLITE_API void *SQLITE_STDCALL sqlite3_realloc(void*, int);
2471SQLITE_API void *SQLITE_STDCALL sqlite3_realloc64(void*, sqlite3_uint64);
2472SQLITE_API void SQLITE_STDCALL sqlite3_free(void*);
2473SQLITE_API sqlite3_uint64 SQLITE_STDCALL sqlite3_msize(void*);
2474
2475/*
2476** CAPI3REF: Memory Allocator Statistics
2477**
2478** SQLite provides these two interfaces for reporting on the status
2479** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
2480** routines, which form the built-in memory allocation subsystem.
2481**
2482** ^The [sqlite3_memory_used()] routine returns the number of bytes
2483** of memory currently outstanding (malloced but not freed).
2484** ^The [sqlite3_memory_highwater()] routine returns the maximum
2485** value of [sqlite3_memory_used()] since the high-water mark
2486** was last reset.  ^The values returned by [sqlite3_memory_used()] and
2487** [sqlite3_memory_highwater()] include any overhead
2488** added by SQLite in its implementation of [sqlite3_malloc()],
2489** but not overhead added by the any underlying system library
2490** routines that [sqlite3_malloc()] may call.
2491**
2492** ^The memory high-water mark is reset to the current value of
2493** [sqlite3_memory_used()] if and only if the parameter to
2494** [sqlite3_memory_highwater()] is true.  ^The value returned
2495** by [sqlite3_memory_highwater(1)] is the high-water mark
2496** prior to the reset.
2497*/
2498SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_memory_used(void);
2499SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_memory_highwater(int resetFlag);
2500
2501/*
2502** CAPI3REF: Pseudo-Random Number Generator
2503**
2504** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
2505** select random [ROWID | ROWIDs] when inserting new records into a table that
2506** already uses the largest possible [ROWID].  The PRNG is also used for
2507** the build-in random() and randomblob() SQL functions.  This interface allows
2508** applications to access the same PRNG for other purposes.
2509**
2510** ^A call to this routine stores N bytes of randomness into buffer P.
2511** ^The P parameter can be a NULL pointer.
2512**
2513** ^If this routine has not been previously called or if the previous
2514** call had N less than one or a NULL pointer for P, then the PRNG is
2515** seeded using randomness obtained from the xRandomness method of
2516** the default [sqlite3_vfs] object.
2517** ^If the previous call to this routine had an N of 1 or more and a
2518** non-NULL P then the pseudo-randomness is generated
2519** internally and without recourse to the [sqlite3_vfs] xRandomness
2520** method.
2521*/
2522SQLITE_API void SQLITE_STDCALL sqlite3_randomness(int N, void *P);
2523
2524/*
2525** CAPI3REF: Compile-Time Authorization Callbacks
2526** METHOD: sqlite3
2527**
2528** ^This routine registers an authorizer callback with a particular
2529** [database connection], supplied in the first argument.
2530** ^The authorizer callback is invoked as SQL statements are being compiled
2531** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
2532** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()].  ^At various
2533** points during the compilation process, as logic is being created
2534** to perform various actions, the authorizer callback is invoked to
2535** see if those actions are allowed.  ^The authorizer callback should
2536** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
2537** specific action but allow the SQL statement to continue to be
2538** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
2539** rejected with an error.  ^If the authorizer callback returns
2540** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
2541** then the [sqlite3_prepare_v2()] or equivalent call that triggered
2542** the authorizer will fail with an error message.
2543**
2544** When the callback returns [SQLITE_OK], that means the operation
2545** requested is ok.  ^When the callback returns [SQLITE_DENY], the
2546** [sqlite3_prepare_v2()] or equivalent call that triggered the
2547** authorizer will fail with an error message explaining that
2548** access is denied.
2549**
2550** ^The first parameter to the authorizer callback is a copy of the third
2551** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
2552** to the callback is an integer [SQLITE_COPY | action code] that specifies
2553** the particular action to be authorized. ^The third through sixth parameters
2554** to the callback are zero-terminated strings that contain additional
2555** details about the action to be authorized.
2556**
2557** ^If the action code is [SQLITE_READ]
2558** and the callback returns [SQLITE_IGNORE] then the
2559** [prepared statement] statement is constructed to substitute
2560** a NULL value in place of the table column that would have
2561** been read if [SQLITE_OK] had been returned.  The [SQLITE_IGNORE]
2562** return can be used to deny an untrusted user access to individual
2563** columns of a table.
2564** ^If the action code is [SQLITE_DELETE] and the callback returns
2565** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
2566** [truncate optimization] is disabled and all rows are deleted individually.
2567**
2568** An authorizer is used when [sqlite3_prepare | preparing]
2569** SQL statements from an untrusted source, to ensure that the SQL statements
2570** do not try to access data they are not allowed to see, or that they do not
2571** try to execute malicious statements that damage the database.  For
2572** example, an application may allow a user to enter arbitrary
2573** SQL queries for evaluation by a database.  But the application does
2574** not want the user to be able to make arbitrary changes to the
2575** database.  An authorizer could then be put in place while the
2576** user-entered SQL is being [sqlite3_prepare | prepared] that
2577** disallows everything except [SELECT] statements.
2578**
2579** Applications that need to process SQL from untrusted sources
2580** might also consider lowering resource limits using [sqlite3_limit()]
2581** and limiting database size using the [max_page_count] [PRAGMA]
2582** in addition to using an authorizer.
2583**
2584** ^(Only a single authorizer can be in place on a database connection
2585** at a time.  Each call to sqlite3_set_authorizer overrides the
2586** previous call.)^  ^Disable the authorizer by installing a NULL callback.
2587** The authorizer is disabled by default.
2588**
2589** The authorizer callback must not do anything that will modify
2590** the database connection that invoked the authorizer callback.
2591** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2592** database connections for the meaning of "modify" in this paragraph.
2593**
2594** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
2595** statement might be re-prepared during [sqlite3_step()] due to a
2596** schema change.  Hence, the application should ensure that the
2597** correct authorizer callback remains in place during the [sqlite3_step()].
2598**
2599** ^Note that the authorizer callback is invoked only during
2600** [sqlite3_prepare()] or its variants.  Authorization is not
2601** performed during statement evaluation in [sqlite3_step()], unless
2602** as stated in the previous paragraph, sqlite3_step() invokes
2603** sqlite3_prepare_v2() to reprepare a statement after a schema change.
2604*/
2605SQLITE_API int SQLITE_STDCALL sqlite3_set_authorizer(
2606  sqlite3*,
2607  int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
2608  void *pUserData
2609);
2610
2611/*
2612** CAPI3REF: Authorizer Return Codes
2613**
2614** The [sqlite3_set_authorizer | authorizer callback function] must
2615** return either [SQLITE_OK] or one of these two constants in order
2616** to signal SQLite whether or not the action is permitted.  See the
2617** [sqlite3_set_authorizer | authorizer documentation] for additional
2618** information.
2619**
2620** Note that SQLITE_IGNORE is also used as a [conflict resolution mode]
2621** returned from the [sqlite3_vtab_on_conflict()] interface.
2622*/
2623#define SQLITE_DENY   1   /* Abort the SQL statement with an error */
2624#define SQLITE_IGNORE 2   /* Don't allow access, but don't generate an error */
2625
2626/*
2627** CAPI3REF: Authorizer Action Codes
2628**
2629** The [sqlite3_set_authorizer()] interface registers a callback function
2630** that is invoked to authorize certain SQL statement actions.  The
2631** second parameter to the callback is an integer code that specifies
2632** what action is being authorized.  These are the integer action codes that
2633** the authorizer callback may be passed.
2634**
2635** These action code values signify what kind of operation is to be
2636** authorized.  The 3rd and 4th parameters to the authorization
2637** callback function will be parameters or NULL depending on which of these
2638** codes is used as the second parameter.  ^(The 5th parameter to the
2639** authorizer callback is the name of the database ("main", "temp",
2640** etc.) if applicable.)^  ^The 6th parameter to the authorizer callback
2641** is the name of the inner-most trigger or view that is responsible for
2642** the access attempt or NULL if this access attempt is directly from
2643** top-level SQL code.
2644*/
2645/******************************************* 3rd ************ 4th ***********/
2646#define SQLITE_CREATE_INDEX          1   /* Index Name      Table Name      */
2647#define SQLITE_CREATE_TABLE          2   /* Table Name      NULL            */
2648#define SQLITE_CREATE_TEMP_INDEX     3   /* Index Name      Table Name      */
2649#define SQLITE_CREATE_TEMP_TABLE     4   /* Table Name      NULL            */
2650#define SQLITE_CREATE_TEMP_TRIGGER   5   /* Trigger Name    Table Name      */
2651#define SQLITE_CREATE_TEMP_VIEW      6   /* View Name       NULL            */
2652#define SQLITE_CREATE_TRIGGER        7   /* Trigger Name    Table Name      */
2653#define SQLITE_CREATE_VIEW           8   /* View Name       NULL            */
2654#define SQLITE_DELETE                9   /* Table Name      NULL            */
2655#define SQLITE_DROP_INDEX           10   /* Index Name      Table Name      */
2656#define SQLITE_DROP_TABLE           11   /* Table Name      NULL            */
2657#define SQLITE_DROP_TEMP_INDEX      12   /* Index Name      Table Name      */
2658#define SQLITE_DROP_TEMP_TABLE      13   /* Table Name      NULL            */
2659#define SQLITE_DROP_TEMP_TRIGGER    14   /* Trigger Name    Table Name      */
2660#define SQLITE_DROP_TEMP_VIEW       15   /* View Name       NULL            */
2661#define SQLITE_DROP_TRIGGER         16   /* Trigger Name    Table Name      */
2662#define SQLITE_DROP_VIEW            17   /* View Name       NULL            */
2663#define SQLITE_INSERT               18   /* Table Name      NULL            */
2664#define SQLITE_PRAGMA               19   /* Pragma Name     1st arg or NULL */
2665#define SQLITE_READ                 20   /* Table Name      Column Name     */
2666#define SQLITE_SELECT               21   /* NULL            NULL            */
2667#define SQLITE_TRANSACTION          22   /* Operation       NULL            */
2668#define SQLITE_UPDATE               23   /* Table Name      Column Name     */
2669#define SQLITE_ATTACH               24   /* Filename        NULL            */
2670#define SQLITE_DETACH               25   /* Database Name   NULL            */
2671#define SQLITE_ALTER_TABLE          26   /* Database Name   Table Name      */
2672#define SQLITE_REINDEX              27   /* Index Name      NULL            */
2673#define SQLITE_ANALYZE              28   /* Table Name      NULL            */
2674#define SQLITE_CREATE_VTABLE        29   /* Table Name      Module Name     */
2675#define SQLITE_DROP_VTABLE          30   /* Table Name      Module Name     */
2676#define SQLITE_FUNCTION             31   /* NULL            Function Name   */
2677#define SQLITE_SAVEPOINT            32   /* Operation       Savepoint Name  */
2678#define SQLITE_COPY                  0   /* No longer used */
2679#define SQLITE_RECURSIVE            33   /* NULL            NULL            */
2680
2681/*
2682** CAPI3REF: Tracing And Profiling Functions
2683** METHOD: sqlite3
2684**
2685** These routines register callback functions that can be used for
2686** tracing and profiling the execution of SQL statements.
2687**
2688** ^The callback function registered by sqlite3_trace() is invoked at
2689** various times when an SQL statement is being run by [sqlite3_step()].
2690** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
2691** SQL statement text as the statement first begins executing.
2692** ^(Additional sqlite3_trace() callbacks might occur
2693** as each triggered subprogram is entered.  The callbacks for triggers
2694** contain a UTF-8 SQL comment that identifies the trigger.)^
2695**
2696** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit
2697** the length of [bound parameter] expansion in the output of sqlite3_trace().
2698**
2699** ^The callback function registered by sqlite3_profile() is invoked
2700** as each SQL statement finishes.  ^The profile callback contains
2701** the original statement text and an estimate of wall-clock time
2702** of how long that statement took to run.  ^The profile callback
2703** time is in units of nanoseconds, however the current implementation
2704** is only capable of millisecond resolution so the six least significant
2705** digits in the time are meaningless.  Future versions of SQLite
2706** might provide greater resolution on the profiler callback.  The
2707** sqlite3_profile() function is considered experimental and is
2708** subject to change in future versions of SQLite.
2709*/
2710SQLITE_API void *SQLITE_STDCALL sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*);
2711SQLITE_API SQLITE_EXPERIMENTAL void *SQLITE_STDCALL sqlite3_profile(sqlite3*,
2712   void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
2713
2714/*
2715** CAPI3REF: Query Progress Callbacks
2716** METHOD: sqlite3
2717**
2718** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
2719** function X to be invoked periodically during long running calls to
2720** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for
2721** database connection D.  An example use for this
2722** interface is to keep a GUI updated during a large query.
2723**
2724** ^The parameter P is passed through as the only parameter to the
2725** callback function X.  ^The parameter N is the approximate number of
2726** [virtual machine instructions] that are evaluated between successive
2727** invocations of the callback X.  ^If N is less than one then the progress
2728** handler is disabled.
2729**
2730** ^Only a single progress handler may be defined at one time per
2731** [database connection]; setting a new progress handler cancels the
2732** old one.  ^Setting parameter X to NULL disables the progress handler.
2733** ^The progress handler is also disabled by setting N to a value less
2734** than 1.
2735**
2736** ^If the progress callback returns non-zero, the operation is
2737** interrupted.  This feature can be used to implement a
2738** "Cancel" button on a GUI progress dialog box.
2739**
2740** The progress handler callback must not do anything that will modify
2741** the database connection that invoked the progress handler.
2742** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2743** database connections for the meaning of "modify" in this paragraph.
2744**
2745*/
2746SQLITE_API void SQLITE_STDCALL sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
2747
2748/*
2749** CAPI3REF: Opening A New Database Connection
2750** CONSTRUCTOR: sqlite3
2751**
2752** ^These routines open an SQLite database file as specified by the
2753** filename argument. ^The filename argument is interpreted as UTF-8 for
2754** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
2755** order for sqlite3_open16(). ^(A [database connection] handle is usually
2756** returned in *ppDb, even if an error occurs.  The only exception is that
2757** if SQLite is unable to allocate memory to hold the [sqlite3] object,
2758** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
2759** object.)^ ^(If the database is opened (and/or created) successfully, then
2760** [SQLITE_OK] is returned.  Otherwise an [error code] is returned.)^ ^The
2761** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
2762** an English language description of the error following a failure of any
2763** of the sqlite3_open() routines.
2764**
2765** ^The default encoding will be UTF-8 for databases created using
2766** sqlite3_open() or sqlite3_open_v2().  ^The default encoding for databases
2767** created using sqlite3_open16() will be UTF-16 in the native byte order.
2768**
2769** Whether or not an error occurs when it is opened, resources
2770** associated with the [database connection] handle should be released by
2771** passing it to [sqlite3_close()] when it is no longer required.
2772**
2773** The sqlite3_open_v2() interface works like sqlite3_open()
2774** except that it accepts two additional parameters for additional control
2775** over the new database connection.  ^(The flags parameter to
2776** sqlite3_open_v2() can take one of
2777** the following three values, optionally combined with the
2778** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE],
2779** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^
2780**
2781** <dl>
2782** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
2783** <dd>The database is opened in read-only mode.  If the database does not
2784** already exist, an error is returned.</dd>)^
2785**
2786** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
2787** <dd>The database is opened for reading and writing if possible, or reading
2788** only if the file is write protected by the operating system.  In either
2789** case the database must already exist, otherwise an error is returned.</dd>)^
2790**
2791** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
2792** <dd>The database is opened for reading and writing, and is created if
2793** it does not already exist. This is the behavior that is always used for
2794** sqlite3_open() and sqlite3_open16().</dd>)^
2795** </dl>
2796**
2797** If the 3rd parameter to sqlite3_open_v2() is not one of the
2798** combinations shown above optionally combined with other
2799** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits]
2800** then the behavior is undefined.
2801**
2802** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection
2803** opens in the multi-thread [threading mode] as long as the single-thread
2804** mode has not been set at compile-time or start-time.  ^If the
2805** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens
2806** in the serialized [threading mode] unless single-thread was
2807** previously selected at compile-time or start-time.
2808** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be
2809** eligible to use [shared cache mode], regardless of whether or not shared
2810** cache is enabled using [sqlite3_enable_shared_cache()].  ^The
2811** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not
2812** participate in [shared cache mode] even if it is enabled.
2813**
2814** ^The fourth parameter to sqlite3_open_v2() is the name of the
2815** [sqlite3_vfs] object that defines the operating system interface that
2816** the new database connection should use.  ^If the fourth parameter is
2817** a NULL pointer then the default [sqlite3_vfs] object is used.
2818**
2819** ^If the filename is ":memory:", then a private, temporary in-memory database
2820** is created for the connection.  ^This in-memory database will vanish when
2821** the database connection is closed.  Future versions of SQLite might
2822** make use of additional special filenames that begin with the ":" character.
2823** It is recommended that when a database filename actually does begin with
2824** a ":" character you should prefix the filename with a pathname such as
2825** "./" to avoid ambiguity.
2826**
2827** ^If the filename is an empty string, then a private, temporary
2828** on-disk database will be created.  ^This private database will be
2829** automatically deleted as soon as the database connection is closed.
2830**
2831** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
2832**
2833** ^If [URI filename] interpretation is enabled, and the filename argument
2834** begins with "file:", then the filename is interpreted as a URI. ^URI
2835** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
2836** set in the fourth argument to sqlite3_open_v2(), or if it has
2837** been enabled globally using the [SQLITE_CONFIG_URI] option with the
2838** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
2839** As of SQLite version 3.7.7, URI filename interpretation is turned off
2840** by default, but future releases of SQLite might enable URI filename
2841** interpretation by default.  See "[URI filenames]" for additional
2842** information.
2843**
2844** URI filenames are parsed according to RFC 3986. ^If the URI contains an
2845** authority, then it must be either an empty string or the string
2846** "localhost". ^If the authority is not an empty string or "localhost", an
2847** error is returned to the caller. ^The fragment component of a URI, if
2848** present, is ignored.
2849**
2850** ^SQLite uses the path component of the URI as the name of the disk file
2851** which contains the database. ^If the path begins with a '/' character,
2852** then it is interpreted as an absolute path. ^If the path does not begin
2853** with a '/' (meaning that the authority section is omitted from the URI)
2854** then the path is interpreted as a relative path.
2855** ^(On windows, the first component of an absolute path
2856** is a drive specification (e.g. "C:").)^
2857**
2858** [[core URI query parameters]]
2859** The query component of a URI may contain parameters that are interpreted
2860** either by SQLite itself, or by a [VFS | custom VFS implementation].
2861** SQLite and its built-in [VFSes] interpret the
2862** following query parameters:
2863**
2864** <ul>
2865**   <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
2866**     a VFS object that provides the operating system interface that should
2867**     be used to access the database file on disk. ^If this option is set to
2868**     an empty string the default VFS object is used. ^Specifying an unknown
2869**     VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
2870**     present, then the VFS specified by the option takes precedence over
2871**     the value passed as the fourth parameter to sqlite3_open_v2().
2872**
2873**   <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw",
2874**     "rwc", or "memory". Attempting to set it to any other value is
2875**     an error)^.
2876**     ^If "ro" is specified, then the database is opened for read-only
2877**     access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the
2878**     third argument to sqlite3_open_v2(). ^If the mode option is set to
2879**     "rw", then the database is opened for read-write (but not create)
2880**     access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had
2881**     been set. ^Value "rwc" is equivalent to setting both
2882**     SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE.  ^If the mode option is
2883**     set to "memory" then a pure [in-memory database] that never reads
2884**     or writes from disk is used. ^It is an error to specify a value for
2885**     the mode parameter that is less restrictive than that specified by
2886**     the flags passed in the third parameter to sqlite3_open_v2().
2887**
2888**   <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
2889**     "private". ^Setting it to "shared" is equivalent to setting the
2890**     SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
2891**     sqlite3_open_v2(). ^Setting the cache parameter to "private" is
2892**     equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
2893**     ^If sqlite3_open_v2() is used and the "cache" parameter is present in
2894**     a URI filename, its value overrides any behavior requested by setting
2895**     SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.
2896**
2897**  <li> <b>psow</b>: ^The psow parameter indicates whether or not the
2898**     [powersafe overwrite] property does or does not apply to the
2899**     storage media on which the database file resides.
2900**
2901**  <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter
2902**     which if set disables file locking in rollback journal modes.  This
2903**     is useful for accessing a database on a filesystem that does not
2904**     support locking.  Caution:  Database corruption might result if two
2905**     or more processes write to the same database and any one of those
2906**     processes uses nolock=1.
2907**
2908**  <li> <b>immutable</b>: ^The immutable parameter is a boolean query
2909**     parameter that indicates that the database file is stored on
2910**     read-only media.  ^When immutable is set, SQLite assumes that the
2911**     database file cannot be changed, even by a process with higher
2912**     privilege, and so the database is opened read-only and all locking
2913**     and change detection is disabled.  Caution: Setting the immutable
2914**     property on a database file that does in fact change can result
2915**     in incorrect query results and/or [SQLITE_CORRUPT] errors.
2916**     See also: [SQLITE_IOCAP_IMMUTABLE].
2917**
2918** </ul>
2919**
2920** ^Specifying an unknown parameter in the query component of a URI is not an
2921** error.  Future versions of SQLite might understand additional query
2922** parameters.  See "[query parameters with special meaning to SQLite]" for
2923** additional information.
2924**
2925** [[URI filename examples]] <h3>URI filename examples</h3>
2926**
2927** <table border="1" align=center cellpadding=5>
2928** <tr><th> URI filenames <th> Results
2929** <tr><td> file:data.db <td>
2930**          Open the file "data.db" in the current directory.
2931** <tr><td> file:/home/fred/data.db<br>
2932**          file:///home/fred/data.db <br>
2933**          file://localhost/home/fred/data.db <br> <td>
2934**          Open the database file "/home/fred/data.db".
2935** <tr><td> file://darkstar/home/fred/data.db <td>
2936**          An error. "darkstar" is not a recognized authority.
2937** <tr><td style="white-space:nowrap">
2938**          file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
2939**     <td> Windows only: Open the file "data.db" on fred's desktop on drive
2940**          C:. Note that the %20 escaping in this example is not strictly
2941**          necessary - space characters can be used literally
2942**          in URI filenames.
2943** <tr><td> file:data.db?mode=ro&cache=private <td>
2944**          Open file "data.db" in the current directory for read-only access.
2945**          Regardless of whether or not shared-cache mode is enabled by
2946**          default, use a private cache.
2947** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td>
2948**          Open file "/home/fred/data.db". Use the special VFS "unix-dotfile"
2949**          that uses dot-files in place of posix advisory locking.
2950** <tr><td> file:data.db?mode=readonly <td>
2951**          An error. "readonly" is not a valid option for the "mode" parameter.
2952** </table>
2953**
2954** ^URI hexadecimal escape sequences (%HH) are supported within the path and
2955** query components of a URI. A hexadecimal escape sequence consists of a
2956** percent sign - "%" - followed by exactly two hexadecimal digits
2957** specifying an octet value. ^Before the path or query components of a
2958** URI filename are interpreted, they are encoded using UTF-8 and all
2959** hexadecimal escape sequences replaced by a single byte containing the
2960** corresponding octet. If this process generates an invalid UTF-8 encoding,
2961** the results are undefined.
2962**
2963** <b>Note to Windows users:</b>  The encoding used for the filename argument
2964** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
2965** codepage is currently defined.  Filenames containing international
2966** characters must be converted to UTF-8 prior to passing them into
2967** sqlite3_open() or sqlite3_open_v2().
2968**
2969** <b>Note to Windows Runtime users:</b>  The temporary directory must be set
2970** prior to calling sqlite3_open() or sqlite3_open_v2().  Otherwise, various
2971** features that require the use of temporary files may fail.
2972**
2973** See also: [sqlite3_temp_directory]
2974*/
2975SQLITE_API int SQLITE_STDCALL sqlite3_open(
2976  const char *filename,   /* Database filename (UTF-8) */
2977  sqlite3 **ppDb          /* OUT: SQLite db handle */
2978);
2979SQLITE_API int SQLITE_STDCALL sqlite3_open16(
2980  const void *filename,   /* Database filename (UTF-16) */
2981  sqlite3 **ppDb          /* OUT: SQLite db handle */
2982);
2983SQLITE_API int SQLITE_STDCALL sqlite3_open_v2(
2984  const char *filename,   /* Database filename (UTF-8) */
2985  sqlite3 **ppDb,         /* OUT: SQLite db handle */
2986  int flags,              /* Flags */
2987  const char *zVfs        /* Name of VFS module to use */
2988);
2989
2990/*
2991** CAPI3REF: Obtain Values For URI Parameters
2992**
2993** These are utility routines, useful to VFS implementations, that check
2994** to see if a database file was a URI that contained a specific query
2995** parameter, and if so obtains the value of that query parameter.
2996**
2997** If F is the database filename pointer passed into the xOpen() method of
2998** a VFS implementation when the flags parameter to xOpen() has one or
2999** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and
3000** P is the name of the query parameter, then
3001** sqlite3_uri_parameter(F,P) returns the value of the P
3002** parameter if it exists or a NULL pointer if P does not appear as a
3003** query parameter on F.  If P is a query parameter of F
3004** has no explicit value, then sqlite3_uri_parameter(F,P) returns
3005** a pointer to an empty string.
3006**
3007** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
3008** parameter and returns true (1) or false (0) according to the value
3009** of P.  The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
3010** value of query parameter P is one of "yes", "true", or "on" in any
3011** case or if the value begins with a non-zero number.  The
3012** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
3013** query parameter P is one of "no", "false", or "off" in any case or
3014** if the value begins with a numeric zero.  If P is not a query
3015** parameter on F or if the value of P is does not match any of the
3016** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).
3017**
3018** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
3019** 64-bit signed integer and returns that integer, or D if P does not
3020** exist.  If the value of P is something other than an integer, then
3021** zero is returned.
3022**
3023** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
3024** sqlite3_uri_boolean(F,P,B) returns B.  If F is not a NULL pointer and
3025** is not a database file pathname pointer that SQLite passed into the xOpen
3026** VFS method, then the behavior of this routine is undefined and probably
3027** undesirable.
3028*/
3029SQLITE_API const char *SQLITE_STDCALL sqlite3_uri_parameter(const char *zFilename, const char *zParam);
3030SQLITE_API int SQLITE_STDCALL sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault);
3031SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_uri_int64(const char*, const char*, sqlite3_int64);
3032
3033
3034/*
3035** CAPI3REF: Error Codes And Messages
3036** METHOD: sqlite3
3037**
3038** ^If the most recent sqlite3_* API call associated with
3039** [database connection] D failed, then the sqlite3_errcode(D) interface
3040** returns the numeric [result code] or [extended result code] for that
3041** API call.
3042** If the most recent API call was successful,
3043** then the return value from sqlite3_errcode() is undefined.
3044** ^The sqlite3_extended_errcode()
3045** interface is the same except that it always returns the
3046** [extended result code] even when extended result codes are
3047** disabled.
3048**
3049** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
3050** text that describes the error, as either UTF-8 or UTF-16 respectively.
3051** ^(Memory to hold the error message string is managed internally.
3052** The application does not need to worry about freeing the result.
3053** However, the error string might be overwritten or deallocated by
3054** subsequent calls to other SQLite interface functions.)^
3055**
3056** ^The sqlite3_errstr() interface returns the English-language text
3057** that describes the [result code], as UTF-8.
3058** ^(Memory to hold the error message string is managed internally
3059** and must not be freed by the application)^.
3060**
3061** When the serialized [threading mode] is in use, it might be the
3062** case that a second error occurs on a separate thread in between
3063** the time of the first error and the call to these interfaces.
3064** When that happens, the second error will be reported since these
3065** interfaces always report the most recent result.  To avoid
3066** this, each thread can obtain exclusive use of the [database connection] D
3067** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
3068** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
3069** all calls to the interfaces listed here are completed.
3070**
3071** If an interface fails with SQLITE_MISUSE, that means the interface
3072** was invoked incorrectly by the application.  In that case, the
3073** error code and message may or may not be set.
3074*/
3075SQLITE_API int SQLITE_STDCALL sqlite3_errcode(sqlite3 *db);
3076SQLITE_API int SQLITE_STDCALL sqlite3_extended_errcode(sqlite3 *db);
3077SQLITE_API const char *SQLITE_STDCALL sqlite3_errmsg(sqlite3*);
3078SQLITE_API const void *SQLITE_STDCALL sqlite3_errmsg16(sqlite3*);
3079SQLITE_API const char *SQLITE_STDCALL sqlite3_errstr(int);
3080
3081/*
3082** CAPI3REF: Prepared Statement Object
3083** KEYWORDS: {prepared statement} {prepared statements}
3084**
3085** An instance of this object represents a single SQL statement that
3086** has been compiled into binary form and is ready to be evaluated.
3087**
3088** Think of each SQL statement as a separate computer program.  The
3089** original SQL text is source code.  A prepared statement object
3090** is the compiled object code.  All SQL must be converted into a
3091** prepared statement before it can be run.
3092**
3093** The life-cycle of a prepared statement object usually goes like this:
3094**
3095** <ol>
3096** <li> Create the prepared statement object using [sqlite3_prepare_v2()].
3097** <li> Bind values to [parameters] using the sqlite3_bind_*()
3098**      interfaces.
3099** <li> Run the SQL by calling [sqlite3_step()] one or more times.
3100** <li> Reset the prepared statement using [sqlite3_reset()] then go back
3101**      to step 2.  Do this zero or more times.
3102** <li> Destroy the object using [sqlite3_finalize()].
3103** </ol>
3104*/
3105typedef struct sqlite3_stmt sqlite3_stmt;
3106
3107/*
3108** CAPI3REF: Run-time Limits
3109** METHOD: sqlite3
3110**
3111** ^(This interface allows the size of various constructs to be limited
3112** on a connection by connection basis.  The first parameter is the
3113** [database connection] whose limit is to be set or queried.  The
3114** second parameter is one of the [limit categories] that define a
3115** class of constructs to be size limited.  The third parameter is the
3116** new limit for that construct.)^
3117**
3118** ^If the new limit is a negative number, the limit is unchanged.
3119** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
3120** [limits | hard upper bound]
3121** set at compile-time by a C preprocessor macro called
3122** [limits | SQLITE_MAX_<i>NAME</i>].
3123** (The "_LIMIT_" in the name is changed to "_MAX_".))^
3124** ^Attempts to increase a limit above its hard upper bound are
3125** silently truncated to the hard upper bound.
3126**
3127** ^Regardless of whether or not the limit was changed, the
3128** [sqlite3_limit()] interface returns the prior value of the limit.
3129** ^Hence, to find the current value of a limit without changing it,
3130** simply invoke this interface with the third parameter set to -1.
3131**
3132** Run-time limits are intended for use in applications that manage
3133** both their own internal database and also databases that are controlled
3134** by untrusted external sources.  An example application might be a
3135** web browser that has its own databases for storing history and
3136** separate databases controlled by JavaScript applications downloaded
3137** off the Internet.  The internal databases can be given the
3138** large, default limits.  Databases managed by external sources can
3139** be given much smaller limits designed to prevent a denial of service
3140** attack.  Developers might also want to use the [sqlite3_set_authorizer()]
3141** interface to further control untrusted SQL.  The size of the database
3142** created by an untrusted script can be contained using the
3143** [max_page_count] [PRAGMA].
3144**
3145** New run-time limit categories may be added in future releases.
3146*/
3147SQLITE_API int SQLITE_STDCALL sqlite3_limit(sqlite3*, int id, int newVal);
3148
3149/*
3150** CAPI3REF: Run-Time Limit Categories
3151** KEYWORDS: {limit category} {*limit categories}
3152**
3153** These constants define various performance limits
3154** that can be lowered at run-time using [sqlite3_limit()].
3155** The synopsis of the meanings of the various limits is shown below.
3156** Additional information is available at [limits | Limits in SQLite].
3157**
3158** <dl>
3159** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt>
3160** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
3161**
3162** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
3163** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
3164**
3165** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt>
3166** <dd>The maximum number of columns in a table definition or in the
3167** result set of a [SELECT] or the maximum number of columns in an index
3168** or in an ORDER BY or GROUP BY clause.</dd>)^
3169**
3170** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
3171** <dd>The maximum depth of the parse tree on any expression.</dd>)^
3172**
3173** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
3174** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
3175**
3176** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
3177** <dd>The maximum number of instructions in a virtual machine program
3178** used to implement an SQL statement.  This limit is not currently
3179** enforced, though that might be added in some future release of
3180** SQLite.</dd>)^
3181**
3182** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
3183** <dd>The maximum number of arguments on a function.</dd>)^
3184**
3185** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
3186** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
3187**
3188** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]]
3189** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
3190** <dd>The maximum length of the pattern argument to the [LIKE] or
3191** [GLOB] operators.</dd>)^
3192**
3193** [[SQLITE_LIMIT_VARIABLE_NUMBER]]
3194** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
3195** <dd>The maximum index number of any [parameter] in an SQL statement.)^
3196**
3197** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
3198** <dd>The maximum depth of recursion for triggers.</dd>)^
3199**
3200** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt>
3201** <dd>The maximum number of auxiliary worker threads that a single
3202** [prepared statement] may start.</dd>)^
3203** </dl>
3204*/
3205#define SQLITE_LIMIT_LENGTH                    0
3206#define SQLITE_LIMIT_SQL_LENGTH                1
3207#define SQLITE_LIMIT_COLUMN                    2
3208#define SQLITE_LIMIT_EXPR_DEPTH                3
3209#define SQLITE_LIMIT_COMPOUND_SELECT           4
3210#define SQLITE_LIMIT_VDBE_OP                   5
3211#define SQLITE_LIMIT_FUNCTION_ARG              6
3212#define SQLITE_LIMIT_ATTACHED                  7
3213#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH       8
3214#define SQLITE_LIMIT_VARIABLE_NUMBER           9
3215#define SQLITE_LIMIT_TRIGGER_DEPTH            10
3216#define SQLITE_LIMIT_WORKER_THREADS           11
3217
3218/*
3219** CAPI3REF: Compiling An SQL Statement
3220** KEYWORDS: {SQL statement compiler}
3221** METHOD: sqlite3
3222** CONSTRUCTOR: sqlite3_stmt
3223**
3224** To execute an SQL query, it must first be compiled into a byte-code
3225** program using one of these routines.
3226**
3227** The first argument, "db", is a [database connection] obtained from a
3228** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
3229** [sqlite3_open16()].  The database connection must not have been closed.
3230**
3231** The second argument, "zSql", is the statement to be compiled, encoded
3232** as either UTF-8 or UTF-16.  The sqlite3_prepare() and sqlite3_prepare_v2()
3233** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2()
3234** use UTF-16.
3235**
3236** ^If the nByte argument is negative, then zSql is read up to the
3237** first zero terminator. ^If nByte is positive, then it is the
3238** number of bytes read from zSql.  ^If nByte is zero, then no prepared
3239** statement is generated.
3240** If the caller knows that the supplied string is nul-terminated, then
3241** there is a small performance advantage to passing an nByte parameter that
3242** is the number of bytes in the input string <i>including</i>
3243** the nul-terminator.
3244**
3245** ^If pzTail is not NULL then *pzTail is made to point to the first byte
3246** past the end of the first SQL statement in zSql.  These routines only
3247** compile the first statement in zSql, so *pzTail is left pointing to
3248** what remains uncompiled.
3249**
3250** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
3251** executed using [sqlite3_step()].  ^If there is an error, *ppStmt is set
3252** to NULL.  ^If the input text contains no SQL (if the input is an empty
3253** string or a comment) then *ppStmt is set to NULL.
3254** The calling procedure is responsible for deleting the compiled
3255** SQL statement using [sqlite3_finalize()] after it has finished with it.
3256** ppStmt may not be NULL.
3257**
3258** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
3259** otherwise an [error code] is returned.
3260**
3261** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are
3262** recommended for all new programs. The two older interfaces are retained
3263** for backwards compatibility, but their use is discouraged.
3264** ^In the "v2" interfaces, the prepared statement
3265** that is returned (the [sqlite3_stmt] object) contains a copy of the
3266** original SQL text. This causes the [sqlite3_step()] interface to
3267** behave differently in three ways:
3268**
3269** <ol>
3270** <li>
3271** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
3272** always used to do, [sqlite3_step()] will automatically recompile the SQL
3273** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY]
3274** retries will occur before sqlite3_step() gives up and returns an error.
3275** </li>
3276**
3277** <li>
3278** ^When an error occurs, [sqlite3_step()] will return one of the detailed
3279** [error codes] or [extended error codes].  ^The legacy behavior was that
3280** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
3281** and the application would have to make a second call to [sqlite3_reset()]
3282** in order to find the underlying cause of the problem. With the "v2" prepare
3283** interfaces, the underlying reason for the error is returned immediately.
3284** </li>
3285**
3286** <li>
3287** ^If the specific value bound to [parameter | host parameter] in the
3288** WHERE clause might influence the choice of query plan for a statement,
3289** then the statement will be automatically recompiled, as if there had been
3290** a schema change, on the first  [sqlite3_step()] call following any change
3291** to the [sqlite3_bind_text | bindings] of that [parameter].
3292** ^The specific value of WHERE-clause [parameter] might influence the
3293** choice of query plan if the parameter is the left-hand side of a [LIKE]
3294** or [GLOB] operator or if the parameter is compared to an indexed column
3295** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled.
3296** </li>
3297** </ol>
3298*/
3299SQLITE_API int SQLITE_STDCALL sqlite3_prepare(
3300  sqlite3 *db,            /* Database handle */
3301  const char *zSql,       /* SQL statement, UTF-8 encoded */
3302  int nByte,              /* Maximum length of zSql in bytes. */
3303  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
3304  const char **pzTail     /* OUT: Pointer to unused portion of zSql */
3305);
3306SQLITE_API int SQLITE_STDCALL sqlite3_prepare_v2(
3307  sqlite3 *db,            /* Database handle */
3308  const char *zSql,       /* SQL statement, UTF-8 encoded */
3309  int nByte,              /* Maximum length of zSql in bytes. */
3310  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
3311  const char **pzTail     /* OUT: Pointer to unused portion of zSql */
3312);
3313SQLITE_API int SQLITE_STDCALL sqlite3_prepare16(
3314  sqlite3 *db,            /* Database handle */
3315  const void *zSql,       /* SQL statement, UTF-16 encoded */
3316  int nByte,              /* Maximum length of zSql in bytes. */
3317  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
3318  const void **pzTail     /* OUT: Pointer to unused portion of zSql */
3319);
3320SQLITE_API int SQLITE_STDCALL sqlite3_prepare16_v2(
3321  sqlite3 *db,            /* Database handle */
3322  const void *zSql,       /* SQL statement, UTF-16 encoded */
3323  int nByte,              /* Maximum length of zSql in bytes. */
3324  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
3325  const void **pzTail     /* OUT: Pointer to unused portion of zSql */
3326);
3327
3328/*
3329** CAPI3REF: Retrieving Statement SQL
3330** METHOD: sqlite3_stmt
3331**
3332** ^This interface can be used to retrieve a saved copy of the original
3333** SQL text used to create a [prepared statement] if that statement was
3334** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()].
3335*/
3336SQLITE_API const char *SQLITE_STDCALL sqlite3_sql(sqlite3_stmt *pStmt);
3337
3338/*
3339** CAPI3REF: Determine If An SQL Statement Writes The Database
3340** METHOD: sqlite3_stmt
3341**
3342** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
3343** and only if the [prepared statement] X makes no direct changes to
3344** the content of the database file.
3345**
3346** Note that [application-defined SQL functions] or
3347** [virtual tables] might change the database indirectly as a side effect.
3348** ^(For example, if an application defines a function "eval()" that
3349** calls [sqlite3_exec()], then the following SQL statement would
3350** change the database file through side-effects:
3351**
3352** <blockquote><pre>
3353**    SELECT eval('DELETE FROM t1') FROM t2;
3354** </pre></blockquote>
3355**
3356** But because the [SELECT] statement does not change the database file
3357** directly, sqlite3_stmt_readonly() would still return true.)^
3358**
3359** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
3360** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
3361** since the statements themselves do not actually modify the database but
3362** rather they control the timing of when other statements modify the
3363** database.  ^The [ATTACH] and [DETACH] statements also cause
3364** sqlite3_stmt_readonly() to return true since, while those statements
3365** change the configuration of a database connection, they do not make
3366** changes to the content of the database files on disk.
3367*/
3368SQLITE_API int SQLITE_STDCALL sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
3369
3370/*
3371** CAPI3REF: Determine If A Prepared Statement Has Been Reset
3372** METHOD: sqlite3_stmt
3373**
3374** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
3375** [prepared statement] S has been stepped at least once using
3376** [sqlite3_step(S)] but has not run to completion and/or has not
3377** been reset using [sqlite3_reset(S)].  ^The sqlite3_stmt_busy(S)
3378** interface returns false if S is a NULL pointer.  If S is not a
3379** NULL pointer and is not a pointer to a valid [prepared statement]
3380** object, then the behavior is undefined and probably undesirable.
3381**
3382** This interface can be used in combination [sqlite3_next_stmt()]
3383** to locate all prepared statements associated with a database
3384** connection that are in need of being reset.  This can be used,
3385** for example, in diagnostic routines to search for prepared
3386** statements that are holding a transaction open.
3387*/
3388SQLITE_API int SQLITE_STDCALL sqlite3_stmt_busy(sqlite3_stmt*);
3389
3390/*
3391** CAPI3REF: Dynamically Typed Value Object
3392** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
3393**
3394** SQLite uses the sqlite3_value object to represent all values
3395** that can be stored in a database table. SQLite uses dynamic typing
3396** for the values it stores.  ^Values stored in sqlite3_value objects
3397** can be integers, floating point values, strings, BLOBs, or NULL.
3398**
3399** An sqlite3_value object may be either "protected" or "unprotected".
3400** Some interfaces require a protected sqlite3_value.  Other interfaces
3401** will accept either a protected or an unprotected sqlite3_value.
3402** Every interface that accepts sqlite3_value arguments specifies
3403** whether or not it requires a protected sqlite3_value.  The
3404** [sqlite3_value_dup()] interface can be used to construct a new
3405** protected sqlite3_value from an unprotected sqlite3_value.
3406**
3407** The terms "protected" and "unprotected" refer to whether or not
3408** a mutex is held.  An internal mutex is held for a protected
3409** sqlite3_value object but no mutex is held for an unprotected
3410** sqlite3_value object.  If SQLite is compiled to be single-threaded
3411** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
3412** or if SQLite is run in one of reduced mutex modes
3413** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
3414** then there is no distinction between protected and unprotected
3415** sqlite3_value objects and they can be used interchangeably.  However,
3416** for maximum code portability it is recommended that applications
3417** still make the distinction between protected and unprotected
3418** sqlite3_value objects even when not strictly required.
3419**
3420** ^The sqlite3_value objects that are passed as parameters into the
3421** implementation of [application-defined SQL functions] are protected.
3422** ^The sqlite3_value object returned by
3423** [sqlite3_column_value()] is unprotected.
3424** Unprotected sqlite3_value objects may only be used with
3425** [sqlite3_result_value()] and [sqlite3_bind_value()].
3426** The [sqlite3_value_blob | sqlite3_value_type()] family of
3427** interfaces require protected sqlite3_value objects.
3428*/
3429typedef struct Mem sqlite3_value;
3430
3431/*
3432** CAPI3REF: SQL Function Context Object
3433**
3434** The context in which an SQL function executes is stored in an
3435** sqlite3_context object.  ^A pointer to an sqlite3_context object
3436** is always first parameter to [application-defined SQL functions].
3437** The application-defined SQL function implementation will pass this
3438** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
3439** [sqlite3_aggregate_context()], [sqlite3_user_data()],
3440** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
3441** and/or [sqlite3_set_auxdata()].
3442*/
3443typedef struct sqlite3_context sqlite3_context;
3444
3445/*
3446** CAPI3REF: Binding Values To Prepared Statements
3447** KEYWORDS: {host parameter} {host parameters} {host parameter name}
3448** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
3449** METHOD: sqlite3_stmt
3450**
3451** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
3452** literals may be replaced by a [parameter] that matches one of following
3453** templates:
3454**
3455** <ul>
3456** <li>  ?
3457** <li>  ?NNN
3458** <li>  :VVV
3459** <li>  @VVV
3460** <li>  $VVV
3461** </ul>
3462**
3463** In the templates above, NNN represents an integer literal,
3464** and VVV represents an alphanumeric identifier.)^  ^The values of these
3465** parameters (also called "host parameter names" or "SQL parameters")
3466** can be set using the sqlite3_bind_*() routines defined here.
3467**
3468** ^The first argument to the sqlite3_bind_*() routines is always
3469** a pointer to the [sqlite3_stmt] object returned from
3470** [sqlite3_prepare_v2()] or its variants.
3471**
3472** ^The second argument is the index of the SQL parameter to be set.
3473** ^The leftmost SQL parameter has an index of 1.  ^When the same named
3474** SQL parameter is used more than once, second and subsequent
3475** occurrences have the same index as the first occurrence.
3476** ^The index for named parameters can be looked up using the
3477** [sqlite3_bind_parameter_index()] API if desired.  ^The index
3478** for "?NNN" parameters is the value of NNN.
3479** ^The NNN value must be between 1 and the [sqlite3_limit()]
3480** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999).
3481**
3482** ^The third argument is the value to bind to the parameter.
3483** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16()
3484** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter
3485** is ignored and the end result is the same as sqlite3_bind_null().
3486**
3487** ^(In those routines that have a fourth argument, its value is the
3488** number of bytes in the parameter.  To be clear: the value is the
3489** number of <u>bytes</u> in the value, not the number of characters.)^
3490** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()
3491** is negative, then the length of the string is
3492** the number of bytes up to the first zero terminator.
3493** If the fourth parameter to sqlite3_bind_blob() is negative, then
3494** the behavior is undefined.
3495** If a non-negative fourth parameter is provided to sqlite3_bind_text()
3496** or sqlite3_bind_text16() or sqlite3_bind_text64() then
3497** that parameter must be the byte offset
3498** where the NUL terminator would occur assuming the string were NUL
3499** terminated.  If any NUL characters occur at byte offsets less than
3500** the value of the fourth parameter then the resulting string value will
3501** contain embedded NULs.  The result of expressions involving strings
3502** with embedded NULs is undefined.
3503**
3504** ^The fifth argument to the BLOB and string binding interfaces
3505** is a destructor used to dispose of the BLOB or
3506** string after SQLite has finished with it.  ^The destructor is called
3507** to dispose of the BLOB or string even if the call to bind API fails.
3508** ^If the fifth argument is
3509** the special value [SQLITE_STATIC], then SQLite assumes that the
3510** information is in static, unmanaged space and does not need to be freed.
3511** ^If the fifth argument has the value [SQLITE_TRANSIENT], then
3512** SQLite makes its own private copy of the data immediately, before
3513** the sqlite3_bind_*() routine returns.
3514**
3515** ^The sixth argument to sqlite3_bind_text64() must be one of
3516** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]
3517** to specify the encoding of the text in the third parameter.  If
3518** the sixth argument to sqlite3_bind_text64() is not one of the
3519** allowed values shown above, or if the text encoding is different
3520** from the encoding specified by the sixth parameter, then the behavior
3521** is undefined.
3522**
3523** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
3524** is filled with zeroes.  ^A zeroblob uses a fixed amount of memory
3525** (just an integer to hold its size) while it is being processed.
3526** Zeroblobs are intended to serve as placeholders for BLOBs whose
3527** content is later written using
3528** [sqlite3_blob_open | incremental BLOB I/O] routines.
3529** ^A negative value for the zeroblob results in a zero-length BLOB.
3530**
3531** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
3532** for the [prepared statement] or with a prepared statement for which
3533** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
3534** then the call will return [SQLITE_MISUSE].  If any sqlite3_bind_()
3535** routine is passed a [prepared statement] that has been finalized, the
3536** result is undefined and probably harmful.
3537**
3538** ^Bindings are not cleared by the [sqlite3_reset()] routine.
3539** ^Unbound parameters are interpreted as NULL.
3540**
3541** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
3542** [error code] if anything goes wrong.
3543** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB
3544** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or
3545** [SQLITE_MAX_LENGTH].
3546** ^[SQLITE_RANGE] is returned if the parameter
3547** index is out of range.  ^[SQLITE_NOMEM] is returned if malloc() fails.
3548**
3549** See also: [sqlite3_bind_parameter_count()],
3550** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
3551*/
3552SQLITE_API int SQLITE_STDCALL sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
3553SQLITE_API int SQLITE_STDCALL sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64,
3554                        void(*)(void*));
3555SQLITE_API int SQLITE_STDCALL sqlite3_bind_double(sqlite3_stmt*, int, double);
3556SQLITE_API int SQLITE_STDCALL sqlite3_bind_int(sqlite3_stmt*, int, int);
3557SQLITE_API int SQLITE_STDCALL sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
3558SQLITE_API int SQLITE_STDCALL sqlite3_bind_null(sqlite3_stmt*, int);
3559SQLITE_API int SQLITE_STDCALL sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*));
3560SQLITE_API int SQLITE_STDCALL sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
3561SQLITE_API int SQLITE_STDCALL sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64,
3562                         void(*)(void*), unsigned char encoding);
3563SQLITE_API int SQLITE_STDCALL sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
3564SQLITE_API int SQLITE_STDCALL sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
3565SQLITE_API int SQLITE_STDCALL sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64);
3566
3567/*
3568** CAPI3REF: Number Of SQL Parameters
3569** METHOD: sqlite3_stmt
3570**
3571** ^This routine can be used to find the number of [SQL parameters]
3572** in a [prepared statement].  SQL parameters are tokens of the
3573** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
3574** placeholders for values that are [sqlite3_bind_blob | bound]
3575** to the parameters at a later time.
3576**
3577** ^(This routine actually returns the index of the largest (rightmost)
3578** parameter. For all forms except ?NNN, this will correspond to the
3579** number of unique parameters.  If parameters of the ?NNN form are used,
3580** there may be gaps in the list.)^
3581**
3582** See also: [sqlite3_bind_blob|sqlite3_bind()],
3583** [sqlite3_bind_parameter_name()], and
3584** [sqlite3_bind_parameter_index()].
3585*/
3586SQLITE_API int SQLITE_STDCALL sqlite3_bind_parameter_count(sqlite3_stmt*);
3587
3588/*
3589** CAPI3REF: Name Of A Host Parameter
3590** METHOD: sqlite3_stmt
3591**
3592** ^The sqlite3_bind_parameter_name(P,N) interface returns
3593** the name of the N-th [SQL parameter] in the [prepared statement] P.
3594** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
3595** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
3596** respectively.
3597** In other words, the initial ":" or "$" or "@" or "?"
3598** is included as part of the name.)^
3599** ^Parameters of the form "?" without a following integer have no name
3600** and are referred to as "nameless" or "anonymous parameters".
3601**
3602** ^The first host parameter has an index of 1, not 0.
3603**
3604** ^If the value N is out of range or if the N-th parameter is
3605** nameless, then NULL is returned.  ^The returned string is
3606** always in UTF-8 encoding even if the named parameter was
3607** originally specified as UTF-16 in [sqlite3_prepare16()] or
3608** [sqlite3_prepare16_v2()].
3609**
3610** See also: [sqlite3_bind_blob|sqlite3_bind()],
3611** [sqlite3_bind_parameter_count()], and
3612** [sqlite3_bind_parameter_index()].
3613*/
3614SQLITE_API const char *SQLITE_STDCALL sqlite3_bind_parameter_name(sqlite3_stmt*, int);
3615
3616/*
3617** CAPI3REF: Index Of A Parameter With A Given Name
3618** METHOD: sqlite3_stmt
3619**
3620** ^Return the index of an SQL parameter given its name.  ^The
3621** index value returned is suitable for use as the second
3622** parameter to [sqlite3_bind_blob|sqlite3_bind()].  ^A zero
3623** is returned if no matching parameter is found.  ^The parameter
3624** name must be given in UTF-8 even if the original statement
3625** was prepared from UTF-16 text using [sqlite3_prepare16_v2()].
3626**
3627** See also: [sqlite3_bind_blob|sqlite3_bind()],
3628** [sqlite3_bind_parameter_count()], and
3629** [sqlite3_bind_parameter_index()].
3630*/
3631SQLITE_API int SQLITE_STDCALL sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
3632
3633/*
3634** CAPI3REF: Reset All Bindings On A Prepared Statement
3635** METHOD: sqlite3_stmt
3636**
3637** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
3638** the [sqlite3_bind_blob | bindings] on a [prepared statement].
3639** ^Use this routine to reset all host parameters to NULL.
3640*/
3641SQLITE_API int SQLITE_STDCALL sqlite3_clear_bindings(sqlite3_stmt*);
3642
3643/*
3644** CAPI3REF: Number Of Columns In A Result Set
3645** METHOD: sqlite3_stmt
3646**
3647** ^Return the number of columns in the result set returned by the
3648** [prepared statement]. ^This routine returns 0 if pStmt is an SQL
3649** statement that does not return data (for example an [UPDATE]).
3650**
3651** See also: [sqlite3_data_count()]
3652*/
3653SQLITE_API int SQLITE_STDCALL sqlite3_column_count(sqlite3_stmt *pStmt);
3654
3655/*
3656** CAPI3REF: Column Names In A Result Set
3657** METHOD: sqlite3_stmt
3658**
3659** ^These routines return the name assigned to a particular column
3660** in the result set of a [SELECT] statement.  ^The sqlite3_column_name()
3661** interface returns a pointer to a zero-terminated UTF-8 string
3662** and sqlite3_column_name16() returns a pointer to a zero-terminated
3663** UTF-16 string.  ^The first parameter is the [prepared statement]
3664** that implements the [SELECT] statement. ^The second parameter is the
3665** column number.  ^The leftmost column is number 0.
3666**
3667** ^The returned string pointer is valid until either the [prepared statement]
3668** is destroyed by [sqlite3_finalize()] or until the statement is automatically
3669** reprepared by the first call to [sqlite3_step()] for a particular run
3670** or until the next call to
3671** sqlite3_column_name() or sqlite3_column_name16() on the same column.
3672**
3673** ^If sqlite3_malloc() fails during the processing of either routine
3674** (for example during a conversion from UTF-8 to UTF-16) then a
3675** NULL pointer is returned.
3676**
3677** ^The name of a result column is the value of the "AS" clause for
3678** that column, if there is an AS clause.  If there is no AS clause
3679** then the name of the column is unspecified and may change from
3680** one release of SQLite to the next.
3681*/
3682SQLITE_API const char *SQLITE_STDCALL sqlite3_column_name(sqlite3_stmt*, int N);
3683SQLITE_API const void *SQLITE_STDCALL sqlite3_column_name16(sqlite3_stmt*, int N);
3684
3685/*
3686** CAPI3REF: Source Of Data In A Query Result
3687** METHOD: sqlite3_stmt
3688**
3689** ^These routines provide a means to determine the database, table, and
3690** table column that is the origin of a particular result column in
3691** [SELECT] statement.
3692** ^The name of the database or table or column can be returned as
3693** either a UTF-8 or UTF-16 string.  ^The _database_ routines return
3694** the database name, the _table_ routines return the table name, and
3695** the origin_ routines return the column name.
3696** ^The returned string is valid until the [prepared statement] is destroyed
3697** using [sqlite3_finalize()] or until the statement is automatically
3698** reprepared by the first call to [sqlite3_step()] for a particular run
3699** or until the same information is requested
3700** again in a different encoding.
3701**
3702** ^The names returned are the original un-aliased names of the
3703** database, table, and column.
3704**
3705** ^The first argument to these interfaces is a [prepared statement].
3706** ^These functions return information about the Nth result column returned by
3707** the statement, where N is the second function argument.
3708** ^The left-most column is column 0 for these routines.
3709**
3710** ^If the Nth column returned by the statement is an expression or
3711** subquery and is not a column value, then all of these functions return
3712** NULL.  ^These routine might also return NULL if a memory allocation error
3713** occurs.  ^Otherwise, they return the name of the attached database, table,
3714** or column that query result column was extracted from.
3715**
3716** ^As with all other SQLite APIs, those whose names end with "16" return
3717** UTF-16 encoded strings and the other functions return UTF-8.
3718**
3719** ^These APIs are only available if the library was compiled with the
3720** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
3721**
3722** If two or more threads call one or more of these routines against the same
3723** prepared statement and column at the same time then the results are
3724** undefined.
3725**
3726** If two or more threads call one or more
3727** [sqlite3_column_database_name | column metadata interfaces]
3728** for the same [prepared statement] and result column
3729** at the same time then the results are undefined.
3730*/
3731SQLITE_API const char *SQLITE_STDCALL sqlite3_column_database_name(sqlite3_stmt*,int);
3732SQLITE_API const void *SQLITE_STDCALL sqlite3_column_database_name16(sqlite3_stmt*,int);
3733SQLITE_API const char *SQLITE_STDCALL sqlite3_column_table_name(sqlite3_stmt*,int);
3734SQLITE_API const void *SQLITE_STDCALL sqlite3_column_table_name16(sqlite3_stmt*,int);
3735SQLITE_API const char *SQLITE_STDCALL sqlite3_column_origin_name(sqlite3_stmt*,int);
3736SQLITE_API const void *SQLITE_STDCALL sqlite3_column_origin_name16(sqlite3_stmt*,int);
3737
3738/*
3739** CAPI3REF: Declared Datatype Of A Query Result
3740** METHOD: sqlite3_stmt
3741**
3742** ^(The first parameter is a [prepared statement].
3743** If this statement is a [SELECT] statement and the Nth column of the
3744** returned result set of that [SELECT] is a table column (not an
3745** expression or subquery) then the declared type of the table
3746** column is returned.)^  ^If the Nth column of the result set is an
3747** expression or subquery, then a NULL pointer is returned.
3748** ^The returned string is always UTF-8 encoded.
3749**
3750** ^(For example, given the database schema:
3751**
3752** CREATE TABLE t1(c1 VARIANT);
3753**
3754** and the following statement to be compiled:
3755**
3756** SELECT c1 + 1, c1 FROM t1;
3757**
3758** this routine would return the string "VARIANT" for the second result
3759** column (i==1), and a NULL pointer for the first result column (i==0).)^
3760**
3761** ^SQLite uses dynamic run-time typing.  ^So just because a column
3762** is declared to contain a particular type does not mean that the
3763** data stored in that column is of the declared type.  SQLite is
3764** strongly typed, but the typing is dynamic not static.  ^Type
3765** is associated with individual values, not with the containers
3766** used to hold those values.
3767*/
3768SQLITE_API const char *SQLITE_STDCALL sqlite3_column_decltype(sqlite3_stmt*,int);
3769SQLITE_API const void *SQLITE_STDCALL sqlite3_column_decltype16(sqlite3_stmt*,int);
3770
3771/*
3772** CAPI3REF: Evaluate An SQL Statement
3773** METHOD: sqlite3_stmt
3774**
3775** After a [prepared statement] has been prepared using either
3776** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy
3777** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
3778** must be called one or more times to evaluate the statement.
3779**
3780** The details of the behavior of the sqlite3_step() interface depend
3781** on whether the statement was prepared using the newer "v2" interface
3782** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy
3783** interface [sqlite3_prepare()] and [sqlite3_prepare16()].  The use of the
3784** new "v2" interface is recommended for new applications but the legacy
3785** interface will continue to be supported.
3786**
3787** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
3788** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
3789** ^With the "v2" interface, any of the other [result codes] or
3790** [extended result codes] might be returned as well.
3791**
3792** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
3793** database locks it needs to do its job.  ^If the statement is a [COMMIT]
3794** or occurs outside of an explicit transaction, then you can retry the
3795** statement.  If the statement is not a [COMMIT] and occurs within an
3796** explicit transaction then you should rollback the transaction before
3797** continuing.
3798**
3799** ^[SQLITE_DONE] means that the statement has finished executing
3800** successfully.  sqlite3_step() should not be called again on this virtual
3801** machine without first calling [sqlite3_reset()] to reset the virtual
3802** machine back to its initial state.
3803**
3804** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
3805** is returned each time a new row of data is ready for processing by the
3806** caller. The values may be accessed using the [column access functions].
3807** sqlite3_step() is called again to retrieve the next row of data.
3808**
3809** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
3810** violation) has occurred.  sqlite3_step() should not be called again on
3811** the VM. More information may be found by calling [sqlite3_errmsg()].
3812** ^With the legacy interface, a more specific error code (for example,
3813** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
3814** can be obtained by calling [sqlite3_reset()] on the
3815** [prepared statement].  ^In the "v2" interface,
3816** the more specific error code is returned directly by sqlite3_step().
3817**
3818** [SQLITE_MISUSE] means that the this routine was called inappropriately.
3819** Perhaps it was called on a [prepared statement] that has
3820** already been [sqlite3_finalize | finalized] or on one that had
3821** previously returned [SQLITE_ERROR] or [SQLITE_DONE].  Or it could
3822** be the case that the same database connection is being used by two or
3823** more threads at the same moment in time.
3824**
3825** For all versions of SQLite up to and including 3.6.23.1, a call to
3826** [sqlite3_reset()] was required after sqlite3_step() returned anything
3827** other than [SQLITE_ROW] before any subsequent invocation of
3828** sqlite3_step().  Failure to reset the prepared statement using
3829** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
3830** sqlite3_step().  But after version 3.6.23.1, sqlite3_step() began
3831** calling [sqlite3_reset()] automatically in this circumstance rather
3832** than returning [SQLITE_MISUSE].  This is not considered a compatibility
3833** break because any application that ever receives an SQLITE_MISUSE error
3834** is broken by definition.  The [SQLITE_OMIT_AUTORESET] compile-time option
3835** can be used to restore the legacy behavior.
3836**
3837** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
3838** API always returns a generic error code, [SQLITE_ERROR], following any
3839** error other than [SQLITE_BUSY] and [SQLITE_MISUSE].  You must call
3840** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
3841** specific [error codes] that better describes the error.
3842** We admit that this is a goofy design.  The problem has been fixed
3843** with the "v2" interface.  If you prepare all of your SQL statements
3844** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead
3845** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
3846** then the more specific [error codes] are returned directly
3847** by sqlite3_step().  The use of the "v2" interface is recommended.
3848*/
3849SQLITE_API int SQLITE_STDCALL sqlite3_step(sqlite3_stmt*);
3850
3851/*
3852** CAPI3REF: Number of columns in a result set
3853** METHOD: sqlite3_stmt
3854**
3855** ^The sqlite3_data_count(P) interface returns the number of columns in the
3856** current row of the result set of [prepared statement] P.
3857** ^If prepared statement P does not have results ready to return
3858** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of
3859** interfaces) then sqlite3_data_count(P) returns 0.
3860** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
3861** ^The sqlite3_data_count(P) routine returns 0 if the previous call to
3862** [sqlite3_step](P) returned [SQLITE_DONE].  ^The sqlite3_data_count(P)
3863** will return non-zero if previous call to [sqlite3_step](P) returned
3864** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum]
3865** where it always returns zero since each step of that multi-step
3866** pragma returns 0 columns of data.
3867**
3868** See also: [sqlite3_column_count()]
3869*/
3870SQLITE_API int SQLITE_STDCALL sqlite3_data_count(sqlite3_stmt *pStmt);
3871
3872/*
3873** CAPI3REF: Fundamental Datatypes
3874** KEYWORDS: SQLITE_TEXT
3875**
3876** ^(Every value in SQLite has one of five fundamental datatypes:
3877**
3878** <ul>
3879** <li> 64-bit signed integer
3880** <li> 64-bit IEEE floating point number
3881** <li> string
3882** <li> BLOB
3883** <li> NULL
3884** </ul>)^
3885**
3886** These constants are codes for each of those types.
3887**
3888** Note that the SQLITE_TEXT constant was also used in SQLite version 2
3889** for a completely different meaning.  Software that links against both
3890** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
3891** SQLITE_TEXT.
3892*/
3893#define SQLITE_INTEGER  1
3894#define SQLITE_FLOAT    2
3895#define SQLITE_BLOB     4
3896#define SQLITE_NULL     5
3897#ifdef SQLITE_TEXT
3898# undef SQLITE_TEXT
3899#else
3900# define SQLITE_TEXT     3
3901#endif
3902#define SQLITE3_TEXT     3
3903
3904/*
3905** CAPI3REF: Result Values From A Query
3906** KEYWORDS: {column access functions}
3907** METHOD: sqlite3_stmt
3908**
3909** ^These routines return information about a single column of the current
3910** result row of a query.  ^In every case the first argument is a pointer
3911** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
3912** that was returned from [sqlite3_prepare_v2()] or one of its variants)
3913** and the second argument is the index of the column for which information
3914** should be returned. ^The leftmost column of the result set has the index 0.
3915** ^The number of columns in the result can be determined using
3916** [sqlite3_column_count()].
3917**
3918** If the SQL statement does not currently point to a valid row, or if the
3919** column index is out of range, the result is undefined.
3920** These routines may only be called when the most recent call to
3921** [sqlite3_step()] has returned [SQLITE_ROW] and neither
3922** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
3923** If any of these routines are called after [sqlite3_reset()] or
3924** [sqlite3_finalize()] or after [sqlite3_step()] has returned
3925** something other than [SQLITE_ROW], the results are undefined.
3926** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
3927** are called from a different thread while any of these routines
3928** are pending, then the results are undefined.
3929**
3930** ^The sqlite3_column_type() routine returns the
3931** [SQLITE_INTEGER | datatype code] for the initial data type
3932** of the result column.  ^The returned value is one of [SQLITE_INTEGER],
3933** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].  The value
3934** returned by sqlite3_column_type() is only meaningful if no type
3935** conversions have occurred as described below.  After a type conversion,
3936** the value returned by sqlite3_column_type() is undefined.  Future
3937** versions of SQLite may change the behavior of sqlite3_column_type()
3938** following a type conversion.
3939**
3940** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
3941** routine returns the number of bytes in that BLOB or string.
3942** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
3943** the string to UTF-8 and then returns the number of bytes.
3944** ^If the result is a numeric value then sqlite3_column_bytes() uses
3945** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
3946** the number of bytes in that string.
3947** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
3948**
3949** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
3950** routine returns the number of bytes in that BLOB or string.
3951** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
3952** the string to UTF-16 and then returns the number of bytes.
3953** ^If the result is a numeric value then sqlite3_column_bytes16() uses
3954** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
3955** the number of bytes in that string.
3956** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
3957**
3958** ^The values returned by [sqlite3_column_bytes()] and
3959** [sqlite3_column_bytes16()] do not include the zero terminators at the end
3960** of the string.  ^For clarity: the values returned by
3961** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
3962** bytes in the string, not the number of characters.
3963**
3964** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
3965** even empty strings, are always zero-terminated.  ^The return
3966** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
3967**
3968** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an
3969** [unprotected sqlite3_value] object.  In a multithreaded environment,
3970** an unprotected sqlite3_value object may only be used safely with
3971** [sqlite3_bind_value()] and [sqlite3_result_value()].
3972** If the [unprotected sqlite3_value] object returned by
3973** [sqlite3_column_value()] is used in any other way, including calls
3974** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
3975** or [sqlite3_value_bytes()], the behavior is not threadsafe.
3976**
3977** These routines attempt to convert the value where appropriate.  ^For
3978** example, if the internal representation is FLOAT and a text result
3979** is requested, [sqlite3_snprintf()] is used internally to perform the
3980** conversion automatically.  ^(The following table details the conversions
3981** that are applied:
3982**
3983** <blockquote>
3984** <table border="1">
3985** <tr><th> Internal<br>Type <th> Requested<br>Type <th>  Conversion
3986**
3987** <tr><td>  NULL    <td> INTEGER   <td> Result is 0
3988** <tr><td>  NULL    <td>  FLOAT    <td> Result is 0.0
3989** <tr><td>  NULL    <td>   TEXT    <td> Result is a NULL pointer
3990** <tr><td>  NULL    <td>   BLOB    <td> Result is a NULL pointer
3991** <tr><td> INTEGER  <td>  FLOAT    <td> Convert from integer to float
3992** <tr><td> INTEGER  <td>   TEXT    <td> ASCII rendering of the integer
3993** <tr><td> INTEGER  <td>   BLOB    <td> Same as INTEGER->TEXT
3994** <tr><td>  FLOAT   <td> INTEGER   <td> [CAST] to INTEGER
3995** <tr><td>  FLOAT   <td>   TEXT    <td> ASCII rendering of the float
3996** <tr><td>  FLOAT   <td>   BLOB    <td> [CAST] to BLOB
3997** <tr><td>  TEXT    <td> INTEGER   <td> [CAST] to INTEGER
3998** <tr><td>  TEXT    <td>  FLOAT    <td> [CAST] to REAL
3999** <tr><td>  TEXT    <td>   BLOB    <td> No change
4000** <tr><td>  BLOB    <td> INTEGER   <td> [CAST] to INTEGER
4001** <tr><td>  BLOB    <td>  FLOAT    <td> [CAST] to REAL
4002** <tr><td>  BLOB    <td>   TEXT    <td> Add a zero terminator if needed
4003** </table>
4004** </blockquote>)^
4005**
4006** Note that when type conversions occur, pointers returned by prior
4007** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
4008** sqlite3_column_text16() may be invalidated.
4009** Type conversions and pointer invalidations might occur
4010** in the following cases:
4011**
4012** <ul>
4013** <li> The initial content is a BLOB and sqlite3_column_text() or
4014**      sqlite3_column_text16() is called.  A zero-terminator might
4015**      need to be added to the string.</li>
4016** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
4017**      sqlite3_column_text16() is called.  The content must be converted
4018**      to UTF-16.</li>
4019** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
4020**      sqlite3_column_text() is called.  The content must be converted
4021**      to UTF-8.</li>
4022** </ul>
4023**
4024** ^Conversions between UTF-16be and UTF-16le are always done in place and do
4025** not invalidate a prior pointer, though of course the content of the buffer
4026** that the prior pointer references will have been modified.  Other kinds
4027** of conversion are done in place when it is possible, but sometimes they
4028** are not possible and in those cases prior pointers are invalidated.
4029**
4030** The safest policy is to invoke these routines
4031** in one of the following ways:
4032**
4033** <ul>
4034**  <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
4035**  <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
4036**  <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
4037** </ul>
4038**
4039** In other words, you should call sqlite3_column_text(),
4040** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
4041** into the desired format, then invoke sqlite3_column_bytes() or
4042** sqlite3_column_bytes16() to find the size of the result.  Do not mix calls
4043** to sqlite3_column_text() or sqlite3_column_blob() with calls to
4044** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
4045** with calls to sqlite3_column_bytes().
4046**
4047** ^The pointers returned are valid until a type conversion occurs as
4048** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
4049** [sqlite3_finalize()] is called.  ^The memory space used to hold strings
4050** and BLOBs is freed automatically.  Do <em>not</em> pass the pointers returned
4051** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
4052** [sqlite3_free()].
4053**
4054** ^(If a memory allocation error occurs during the evaluation of any
4055** of these routines, a default value is returned.  The default value
4056** is either the integer 0, the floating point number 0.0, or a NULL
4057** pointer.  Subsequent calls to [sqlite3_errcode()] will return
4058** [SQLITE_NOMEM].)^
4059*/
4060SQLITE_API const void *SQLITE_STDCALL sqlite3_column_blob(sqlite3_stmt*, int iCol);
4061SQLITE_API int SQLITE_STDCALL sqlite3_column_bytes(sqlite3_stmt*, int iCol);
4062SQLITE_API int SQLITE_STDCALL sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
4063SQLITE_API double SQLITE_STDCALL sqlite3_column_double(sqlite3_stmt*, int iCol);
4064SQLITE_API int SQLITE_STDCALL sqlite3_column_int(sqlite3_stmt*, int iCol);
4065SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_column_int64(sqlite3_stmt*, int iCol);
4066SQLITE_API const unsigned char *SQLITE_STDCALL sqlite3_column_text(sqlite3_stmt*, int iCol);
4067SQLITE_API const void *SQLITE_STDCALL sqlite3_column_text16(sqlite3_stmt*, int iCol);
4068SQLITE_API int SQLITE_STDCALL sqlite3_column_type(sqlite3_stmt*, int iCol);
4069SQLITE_API sqlite3_value *SQLITE_STDCALL sqlite3_column_value(sqlite3_stmt*, int iCol);
4070
4071/*
4072** CAPI3REF: Destroy A Prepared Statement Object
4073** DESTRUCTOR: sqlite3_stmt
4074**
4075** ^The sqlite3_finalize() function is called to delete a [prepared statement].
4076** ^If the most recent evaluation of the statement encountered no errors
4077** or if the statement is never been evaluated, then sqlite3_finalize() returns
4078** SQLITE_OK.  ^If the most recent evaluation of statement S failed, then
4079** sqlite3_finalize(S) returns the appropriate [error code] or
4080** [extended error code].
4081**
4082** ^The sqlite3_finalize(S) routine can be called at any point during
4083** the life cycle of [prepared statement] S:
4084** before statement S is ever evaluated, after
4085** one or more calls to [sqlite3_reset()], or after any call
4086** to [sqlite3_step()] regardless of whether or not the statement has
4087** completed execution.
4088**
4089** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
4090**
4091** The application must finalize every [prepared statement] in order to avoid
4092** resource leaks.  It is a grievous error for the application to try to use
4093** a prepared statement after it has been finalized.  Any use of a prepared
4094** statement after it has been finalized can result in undefined and
4095** undesirable behavior such as segfaults and heap corruption.
4096*/
4097SQLITE_API int SQLITE_STDCALL sqlite3_finalize(sqlite3_stmt *pStmt);
4098
4099/*
4100** CAPI3REF: Reset A Prepared Statement Object
4101** METHOD: sqlite3_stmt
4102**
4103** The sqlite3_reset() function is called to reset a [prepared statement]
4104** object back to its initial state, ready to be re-executed.
4105** ^Any SQL statement variables that had values bound to them using
4106** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
4107** Use [sqlite3_clear_bindings()] to reset the bindings.
4108**
4109** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
4110** back to the beginning of its program.
4111**
4112** ^If the most recent call to [sqlite3_step(S)] for the
4113** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
4114** or if [sqlite3_step(S)] has never before been called on S,
4115** then [sqlite3_reset(S)] returns [SQLITE_OK].
4116**
4117** ^If the most recent call to [sqlite3_step(S)] for the
4118** [prepared statement] S indicated an error, then
4119** [sqlite3_reset(S)] returns an appropriate [error code].
4120**
4121** ^The [sqlite3_reset(S)] interface does not change the values
4122** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
4123*/
4124SQLITE_API int SQLITE_STDCALL sqlite3_reset(sqlite3_stmt *pStmt);
4125
4126/*
4127** CAPI3REF: Create Or Redefine SQL Functions
4128** KEYWORDS: {function creation routines}
4129** KEYWORDS: {application-defined SQL function}
4130** KEYWORDS: {application-defined SQL functions}
4131** METHOD: sqlite3
4132**
4133** ^These functions (collectively known as "function creation routines")
4134** are used to add SQL functions or aggregates or to redefine the behavior
4135** of existing SQL functions or aggregates.  The only differences between
4136** these routines are the text encoding expected for
4137** the second parameter (the name of the function being created)
4138** and the presence or absence of a destructor callback for
4139** the application data pointer.
4140**
4141** ^The first parameter is the [database connection] to which the SQL
4142** function is to be added.  ^If an application uses more than one database
4143** connection then application-defined SQL functions must be added
4144** to each database connection separately.
4145**
4146** ^The second parameter is the name of the SQL function to be created or
4147** redefined.  ^The length of the name is limited to 255 bytes in a UTF-8
4148** representation, exclusive of the zero-terminator.  ^Note that the name
4149** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
4150** ^Any attempt to create a function with a longer name
4151** will result in [SQLITE_MISUSE] being returned.
4152**
4153** ^The third parameter (nArg)
4154** is the number of arguments that the SQL function or
4155** aggregate takes. ^If this parameter is -1, then the SQL function or
4156** aggregate may take any number of arguments between 0 and the limit
4157** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]).  If the third
4158** parameter is less than -1 or greater than 127 then the behavior is
4159** undefined.
4160**
4161** ^The fourth parameter, eTextRep, specifies what
4162** [SQLITE_UTF8 | text encoding] this SQL function prefers for
4163** its parameters.  The application should set this parameter to
4164** [SQLITE_UTF16LE] if the function implementation invokes
4165** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the
4166** implementation invokes [sqlite3_value_text16be()] on an input, or
4167** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8]
4168** otherwise.  ^The same SQL function may be registered multiple times using
4169** different preferred text encodings, with different implementations for
4170** each encoding.
4171** ^When multiple implementations of the same function are available, SQLite
4172** will pick the one that involves the least amount of data conversion.
4173**
4174** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC]
4175** to signal that the function will always return the same result given
4176** the same inputs within a single SQL statement.  Most SQL functions are
4177** deterministic.  The built-in [random()] SQL function is an example of a
4178** function that is not deterministic.  The SQLite query planner is able to
4179** perform additional optimizations on deterministic functions, so use
4180** of the [SQLITE_DETERMINISTIC] flag is recommended where possible.
4181**
4182** ^(The fifth parameter is an arbitrary pointer.  The implementation of the
4183** function can gain access to this pointer using [sqlite3_user_data()].)^
4184**
4185** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are
4186** pointers to C-language functions that implement the SQL function or
4187** aggregate. ^A scalar SQL function requires an implementation of the xFunc
4188** callback only; NULL pointers must be passed as the xStep and xFinal
4189** parameters. ^An aggregate SQL function requires an implementation of xStep
4190** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
4191** SQL function or aggregate, pass NULL pointers for all three function
4192** callbacks.
4193**
4194** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL,
4195** then it is destructor for the application data pointer.
4196** The destructor is invoked when the function is deleted, either by being
4197** overloaded or when the database connection closes.)^
4198** ^The destructor is also invoked if the call to
4199** sqlite3_create_function_v2() fails.
4200** ^When the destructor callback of the tenth parameter is invoked, it
4201** is passed a single argument which is a copy of the application data
4202** pointer which was the fifth parameter to sqlite3_create_function_v2().
4203**
4204** ^It is permitted to register multiple implementations of the same
4205** functions with the same name but with either differing numbers of
4206** arguments or differing preferred text encodings.  ^SQLite will use
4207** the implementation that most closely matches the way in which the
4208** SQL function is used.  ^A function implementation with a non-negative
4209** nArg parameter is a better match than a function implementation with
4210** a negative nArg.  ^A function where the preferred text encoding
4211** matches the database encoding is a better
4212** match than a function where the encoding is different.
4213** ^A function where the encoding difference is between UTF16le and UTF16be
4214** is a closer match than a function where the encoding difference is
4215** between UTF8 and UTF16.
4216**
4217** ^Built-in functions may be overloaded by new application-defined functions.
4218**
4219** ^An application-defined function is permitted to call other
4220** SQLite interfaces.  However, such calls must not
4221** close the database connection nor finalize or reset the prepared
4222** statement in which the function is running.
4223*/
4224SQLITE_API int SQLITE_STDCALL sqlite3_create_function(
4225  sqlite3 *db,
4226  const char *zFunctionName,
4227  int nArg,
4228  int eTextRep,
4229  void *pApp,
4230  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4231  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4232  void (*xFinal)(sqlite3_context*)
4233);
4234SQLITE_API int SQLITE_STDCALL sqlite3_create_function16(
4235  sqlite3 *db,
4236  const void *zFunctionName,
4237  int nArg,
4238  int eTextRep,
4239  void *pApp,
4240  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4241  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4242  void (*xFinal)(sqlite3_context*)
4243);
4244SQLITE_API int SQLITE_STDCALL sqlite3_create_function_v2(
4245  sqlite3 *db,
4246  const char *zFunctionName,
4247  int nArg,
4248  int eTextRep,
4249  void *pApp,
4250  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4251  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4252  void (*xFinal)(sqlite3_context*),
4253  void(*xDestroy)(void*)
4254);
4255
4256/*
4257** CAPI3REF: Text Encodings
4258**
4259** These constant define integer codes that represent the various
4260** text encodings supported by SQLite.
4261*/
4262#define SQLITE_UTF8           1    /* IMP: R-37514-35566 */
4263#define SQLITE_UTF16LE        2    /* IMP: R-03371-37637 */
4264#define SQLITE_UTF16BE        3    /* IMP: R-51971-34154 */
4265#define SQLITE_UTF16          4    /* Use native byte order */
4266#define SQLITE_ANY            5    /* Deprecated */
4267#define SQLITE_UTF16_ALIGNED  8    /* sqlite3_create_collation only */
4268
4269/*
4270** CAPI3REF: Function Flags
4271**
4272** These constants may be ORed together with the
4273** [SQLITE_UTF8 | preferred text encoding] as the fourth argument
4274** to [sqlite3_create_function()], [sqlite3_create_function16()], or
4275** [sqlite3_create_function_v2()].
4276*/
4277#define SQLITE_DETERMINISTIC    0x800
4278
4279/*
4280** CAPI3REF: Deprecated Functions
4281** DEPRECATED
4282**
4283** These functions are [deprecated].  In order to maintain
4284** backwards compatibility with older code, these functions continue
4285** to be supported.  However, new applications should avoid
4286** the use of these functions.  To encourage programmers to avoid
4287** these functions, we will not explain what they do.
4288*/
4289#ifndef SQLITE_OMIT_DEPRECATED
4290SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_aggregate_count(sqlite3_context*);
4291SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_expired(sqlite3_stmt*);
4292SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
4293SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_global_recover(void);
4294SQLITE_API SQLITE_DEPRECATED void SQLITE_STDCALL sqlite3_thread_cleanup(void);
4295SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),
4296                      void*,sqlite3_int64);
4297#endif
4298
4299/*
4300** CAPI3REF: Obtaining SQL Values
4301** METHOD: sqlite3_value
4302**
4303** The C-language implementation of SQL functions and aggregates uses
4304** this set of interface routines to access the parameter values on
4305** the function or aggregate.
4306**
4307** The xFunc (for scalar functions) or xStep (for aggregates) parameters
4308** to [sqlite3_create_function()] and [sqlite3_create_function16()]
4309** define callbacks that implement the SQL functions and aggregates.
4310** The 3rd parameter to these callbacks is an array of pointers to
4311** [protected sqlite3_value] objects.  There is one [sqlite3_value] object for
4312** each parameter to the SQL function.  These routines are used to
4313** extract values from the [sqlite3_value] objects.
4314**
4315** These routines work only with [protected sqlite3_value] objects.
4316** Any attempt to use these routines on an [unprotected sqlite3_value]
4317** object results in undefined behavior.
4318**
4319** ^These routines work just like the corresponding [column access functions]
4320** except that these routines take a single [protected sqlite3_value] object
4321** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
4322**
4323** ^The sqlite3_value_text16() interface extracts a UTF-16 string
4324** in the native byte-order of the host machine.  ^The
4325** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
4326** extract UTF-16 strings as big-endian and little-endian respectively.
4327**
4328** ^(The sqlite3_value_numeric_type() interface attempts to apply
4329** numeric affinity to the value.  This means that an attempt is
4330** made to convert the value to an integer or floating point.  If
4331** such a conversion is possible without loss of information (in other
4332** words, if the value is a string that looks like a number)
4333** then the conversion is performed.  Otherwise no conversion occurs.
4334** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
4335**
4336** Please pay particular attention to the fact that the pointer returned
4337** from [sqlite3_value_blob()], [sqlite3_value_text()], or
4338** [sqlite3_value_text16()] can be invalidated by a subsequent call to
4339** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
4340** or [sqlite3_value_text16()].
4341**
4342** These routines must be called from the same thread as
4343** the SQL function that supplied the [sqlite3_value*] parameters.
4344*/
4345SQLITE_API const void *SQLITE_STDCALL sqlite3_value_blob(sqlite3_value*);
4346SQLITE_API int SQLITE_STDCALL sqlite3_value_bytes(sqlite3_value*);
4347SQLITE_API int SQLITE_STDCALL sqlite3_value_bytes16(sqlite3_value*);
4348SQLITE_API double SQLITE_STDCALL sqlite3_value_double(sqlite3_value*);
4349SQLITE_API int SQLITE_STDCALL sqlite3_value_int(sqlite3_value*);
4350SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_value_int64(sqlite3_value*);
4351SQLITE_API const unsigned char *SQLITE_STDCALL sqlite3_value_text(sqlite3_value*);
4352SQLITE_API const void *SQLITE_STDCALL sqlite3_value_text16(sqlite3_value*);
4353SQLITE_API const void *SQLITE_STDCALL sqlite3_value_text16le(sqlite3_value*);
4354SQLITE_API const void *SQLITE_STDCALL sqlite3_value_text16be(sqlite3_value*);
4355SQLITE_API int SQLITE_STDCALL sqlite3_value_type(sqlite3_value*);
4356SQLITE_API int SQLITE_STDCALL sqlite3_value_numeric_type(sqlite3_value*);
4357
4358/*
4359** CAPI3REF: Copy And Free SQL Values
4360** METHOD: sqlite3_value
4361**
4362** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value]
4363** object D and returns a pointer to that copy.  ^The [sqlite3_value] returned
4364** is a [protected sqlite3_value] object even if the input is not.
4365** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a
4366** memory allocation fails.
4367**
4368** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object
4369** previously obtained from [sqlite3_value_dup()].  ^If V is a NULL pointer
4370** then sqlite3_value_free(V) is a harmless no-op.
4371*/
4372SQLITE_API SQLITE_EXPERIMENTAL sqlite3_value *SQLITE_STDCALL sqlite3_value_dup(const sqlite3_value*);
4373SQLITE_API SQLITE_EXPERIMENTAL void SQLITE_STDCALL sqlite3_value_free(sqlite3_value*);
4374
4375/*
4376** CAPI3REF: Obtain Aggregate Function Context
4377** METHOD: sqlite3_context
4378**
4379** Implementations of aggregate SQL functions use this
4380** routine to allocate memory for storing their state.
4381**
4382** ^The first time the sqlite3_aggregate_context(C,N) routine is called
4383** for a particular aggregate function, SQLite
4384** allocates N of memory, zeroes out that memory, and returns a pointer
4385** to the new memory. ^On second and subsequent calls to
4386** sqlite3_aggregate_context() for the same aggregate function instance,
4387** the same buffer is returned.  Sqlite3_aggregate_context() is normally
4388** called once for each invocation of the xStep callback and then one
4389** last time when the xFinal callback is invoked.  ^(When no rows match
4390** an aggregate query, the xStep() callback of the aggregate function
4391** implementation is never called and xFinal() is called exactly once.
4392** In those cases, sqlite3_aggregate_context() might be called for the
4393** first time from within xFinal().)^
4394**
4395** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer
4396** when first called if N is less than or equal to zero or if a memory
4397** allocate error occurs.
4398**
4399** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
4400** determined by the N parameter on first successful call.  Changing the
4401** value of N in subsequent call to sqlite3_aggregate_context() within
4402** the same aggregate function instance will not resize the memory
4403** allocation.)^  Within the xFinal callback, it is customary to set
4404** N=0 in calls to sqlite3_aggregate_context(C,N) so that no
4405** pointless memory allocations occur.
4406**
4407** ^SQLite automatically frees the memory allocated by
4408** sqlite3_aggregate_context() when the aggregate query concludes.
4409**
4410** The first parameter must be a copy of the
4411** [sqlite3_context | SQL function context] that is the first parameter
4412** to the xStep or xFinal callback routine that implements the aggregate
4413** function.
4414**
4415** This routine must be called from the same thread in which
4416** the aggregate SQL function is running.
4417*/
4418SQLITE_API void *SQLITE_STDCALL sqlite3_aggregate_context(sqlite3_context*, int nBytes);
4419
4420/*
4421** CAPI3REF: User Data For Functions
4422** METHOD: sqlite3_context
4423**
4424** ^The sqlite3_user_data() interface returns a copy of
4425** the pointer that was the pUserData parameter (the 5th parameter)
4426** of the [sqlite3_create_function()]
4427** and [sqlite3_create_function16()] routines that originally
4428** registered the application defined function.
4429**
4430** This routine must be called from the same thread in which
4431** the application-defined function is running.
4432*/
4433SQLITE_API void *SQLITE_STDCALL sqlite3_user_data(sqlite3_context*);
4434
4435/*
4436** CAPI3REF: Database Connection For Functions
4437** METHOD: sqlite3_context
4438**
4439** ^The sqlite3_context_db_handle() interface returns a copy of
4440** the pointer to the [database connection] (the 1st parameter)
4441** of the [sqlite3_create_function()]
4442** and [sqlite3_create_function16()] routines that originally
4443** registered the application defined function.
4444*/
4445SQLITE_API sqlite3 *SQLITE_STDCALL sqlite3_context_db_handle(sqlite3_context*);
4446
4447/*
4448** CAPI3REF: Function Auxiliary Data
4449** METHOD: sqlite3_context
4450**
4451** These functions may be used by (non-aggregate) SQL functions to
4452** associate metadata with argument values. If the same value is passed to
4453** multiple invocations of the same SQL function during query execution, under
4454** some circumstances the associated metadata may be preserved.  An example
4455** of where this might be useful is in a regular-expression matching
4456** function. The compiled version of the regular expression can be stored as
4457** metadata associated with the pattern string.
4458** Then as long as the pattern string remains the same,
4459** the compiled regular expression can be reused on multiple
4460** invocations of the same function.
4461**
4462** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata
4463** associated by the sqlite3_set_auxdata() function with the Nth argument
4464** value to the application-defined function. ^If there is no metadata
4465** associated with the function argument, this sqlite3_get_auxdata() interface
4466** returns a NULL pointer.
4467**
4468** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th
4469** argument of the application-defined function.  ^Subsequent
4470** calls to sqlite3_get_auxdata(C,N) return P from the most recent
4471** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or
4472** NULL if the metadata has been discarded.
4473** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL,
4474** SQLite will invoke the destructor function X with parameter P exactly
4475** once, when the metadata is discarded.
4476** SQLite is free to discard the metadata at any time, including: <ul>
4477** <li> when the corresponding function parameter changes, or
4478** <li> when [sqlite3_reset()] or [sqlite3_finalize()] is called for the
4479**      SQL statement, or
4480** <li> when sqlite3_set_auxdata() is invoked again on the same parameter, or
4481** <li> during the original sqlite3_set_auxdata() call when a memory
4482**      allocation error occurs. </ul>)^
4483**
4484** Note the last bullet in particular.  The destructor X in
4485** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the
4486** sqlite3_set_auxdata() interface even returns.  Hence sqlite3_set_auxdata()
4487** should be called near the end of the function implementation and the
4488** function implementation should not make any use of P after
4489** sqlite3_set_auxdata() has been called.
4490**
4491** ^(In practice, metadata is preserved between function calls for
4492** function parameters that are compile-time constants, including literal
4493** values and [parameters] and expressions composed from the same.)^
4494**
4495** These routines must be called from the same thread in which
4496** the SQL function is running.
4497*/
4498SQLITE_API void *SQLITE_STDCALL sqlite3_get_auxdata(sqlite3_context*, int N);
4499SQLITE_API void SQLITE_STDCALL sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
4500
4501
4502/*
4503** CAPI3REF: Constants Defining Special Destructor Behavior
4504**
4505** These are special values for the destructor that is passed in as the
4506** final argument to routines like [sqlite3_result_blob()].  ^If the destructor
4507** argument is SQLITE_STATIC, it means that the content pointer is constant
4508** and will never change.  It does not need to be destroyed.  ^The
4509** SQLITE_TRANSIENT value means that the content will likely change in
4510** the near future and that SQLite should make its own private copy of
4511** the content before returning.
4512**
4513** The typedef is necessary to work around problems in certain
4514** C++ compilers.
4515*/
4516typedef void (*sqlite3_destructor_type)(void*);
4517#define SQLITE_STATIC      ((sqlite3_destructor_type)0)
4518#define SQLITE_TRANSIENT   ((sqlite3_destructor_type)-1)
4519
4520/*
4521** CAPI3REF: Setting The Result Of An SQL Function
4522** METHOD: sqlite3_context
4523**
4524** These routines are used by the xFunc or xFinal callbacks that
4525** implement SQL functions and aggregates.  See
4526** [sqlite3_create_function()] and [sqlite3_create_function16()]
4527** for additional information.
4528**
4529** These functions work very much like the [parameter binding] family of
4530** functions used to bind values to host parameters in prepared statements.
4531** Refer to the [SQL parameter] documentation for additional information.
4532**
4533** ^The sqlite3_result_blob() interface sets the result from
4534** an application-defined function to be the BLOB whose content is pointed
4535** to by the second parameter and which is N bytes long where N is the
4536** third parameter.
4537**
4538** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N)
4539** interfaces set the result of the application-defined function to be
4540** a BLOB containing all zero bytes and N bytes in size.
4541**
4542** ^The sqlite3_result_double() interface sets the result from
4543** an application-defined function to be a floating point value specified
4544** by its 2nd argument.
4545**
4546** ^The sqlite3_result_error() and sqlite3_result_error16() functions
4547** cause the implemented SQL function to throw an exception.
4548** ^SQLite uses the string pointed to by the
4549** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
4550** as the text of an error message.  ^SQLite interprets the error
4551** message string from sqlite3_result_error() as UTF-8. ^SQLite
4552** interprets the string from sqlite3_result_error16() as UTF-16 in native
4553** byte order.  ^If the third parameter to sqlite3_result_error()
4554** or sqlite3_result_error16() is negative then SQLite takes as the error
4555** message all text up through the first zero character.
4556** ^If the third parameter to sqlite3_result_error() or
4557** sqlite3_result_error16() is non-negative then SQLite takes that many
4558** bytes (not characters) from the 2nd parameter as the error message.
4559** ^The sqlite3_result_error() and sqlite3_result_error16()
4560** routines make a private copy of the error message text before
4561** they return.  Hence, the calling function can deallocate or
4562** modify the text after they return without harm.
4563** ^The sqlite3_result_error_code() function changes the error code
4564** returned by SQLite as a result of an error in a function.  ^By default,
4565** the error code is SQLITE_ERROR.  ^A subsequent call to sqlite3_result_error()
4566** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
4567**
4568** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an
4569** error indicating that a string or BLOB is too long to represent.
4570**
4571** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an
4572** error indicating that a memory allocation failed.
4573**
4574** ^The sqlite3_result_int() interface sets the return value
4575** of the application-defined function to be the 32-bit signed integer
4576** value given in the 2nd argument.
4577** ^The sqlite3_result_int64() interface sets the return value
4578** of the application-defined function to be the 64-bit signed integer
4579** value given in the 2nd argument.
4580**
4581** ^The sqlite3_result_null() interface sets the return value
4582** of the application-defined function to be NULL.
4583**
4584** ^The sqlite3_result_text(), sqlite3_result_text16(),
4585** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
4586** set the return value of the application-defined function to be
4587** a text string which is represented as UTF-8, UTF-16 native byte order,
4588** UTF-16 little endian, or UTF-16 big endian, respectively.
4589** ^The sqlite3_result_text64() interface sets the return value of an
4590** application-defined function to be a text string in an encoding
4591** specified by the fifth (and last) parameter, which must be one
4592** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE].
4593** ^SQLite takes the text result from the application from
4594** the 2nd parameter of the sqlite3_result_text* interfaces.
4595** ^If the 3rd parameter to the sqlite3_result_text* interfaces
4596** is negative, then SQLite takes result text from the 2nd parameter
4597** through the first zero character.
4598** ^If the 3rd parameter to the sqlite3_result_text* interfaces
4599** is non-negative, then as many bytes (not characters) of the text
4600** pointed to by the 2nd parameter are taken as the application-defined
4601** function result.  If the 3rd parameter is non-negative, then it
4602** must be the byte offset into the string where the NUL terminator would
4603** appear if the string where NUL terminated.  If any NUL characters occur
4604** in the string at a byte offset that is less than the value of the 3rd
4605** parameter, then the resulting string will contain embedded NULs and the
4606** result of expressions operating on strings with embedded NULs is undefined.
4607** ^If the 4th parameter to the sqlite3_result_text* interfaces
4608** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
4609** function as the destructor on the text or BLOB result when it has
4610** finished using that result.
4611** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
4612** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
4613** assumes that the text or BLOB result is in constant space and does not
4614** copy the content of the parameter nor call a destructor on the content
4615** when it has finished using that result.
4616** ^If the 4th parameter to the sqlite3_result_text* interfaces
4617** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
4618** then SQLite makes a copy of the result into space obtained from
4619** from [sqlite3_malloc()] before it returns.
4620**
4621** ^The sqlite3_result_value() interface sets the result of
4622** the application-defined function to be a copy of the
4623** [unprotected sqlite3_value] object specified by the 2nd parameter.  ^The
4624** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
4625** so that the [sqlite3_value] specified in the parameter may change or
4626** be deallocated after sqlite3_result_value() returns without harm.
4627** ^A [protected sqlite3_value] object may always be used where an
4628** [unprotected sqlite3_value] object is required, so either
4629** kind of [sqlite3_value] object can be used with this interface.
4630**
4631** If these routines are called from within the different thread
4632** than the one containing the application-defined function that received
4633** the [sqlite3_context] pointer, the results are undefined.
4634*/
4635SQLITE_API void SQLITE_STDCALL sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
4636SQLITE_API void SQLITE_STDCALL sqlite3_result_blob64(sqlite3_context*,const void*,
4637                           sqlite3_uint64,void(*)(void*));
4638SQLITE_API void SQLITE_STDCALL sqlite3_result_double(sqlite3_context*, double);
4639SQLITE_API void SQLITE_STDCALL sqlite3_result_error(sqlite3_context*, const char*, int);
4640SQLITE_API void SQLITE_STDCALL sqlite3_result_error16(sqlite3_context*, const void*, int);
4641SQLITE_API void SQLITE_STDCALL sqlite3_result_error_toobig(sqlite3_context*);
4642SQLITE_API void SQLITE_STDCALL sqlite3_result_error_nomem(sqlite3_context*);
4643SQLITE_API void SQLITE_STDCALL sqlite3_result_error_code(sqlite3_context*, int);
4644SQLITE_API void SQLITE_STDCALL sqlite3_result_int(sqlite3_context*, int);
4645SQLITE_API void SQLITE_STDCALL sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
4646SQLITE_API void SQLITE_STDCALL sqlite3_result_null(sqlite3_context*);
4647SQLITE_API void SQLITE_STDCALL sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
4648SQLITE_API void SQLITE_STDCALL sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64,
4649                           void(*)(void*), unsigned char encoding);
4650SQLITE_API void SQLITE_STDCALL sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
4651SQLITE_API void SQLITE_STDCALL sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
4652SQLITE_API void SQLITE_STDCALL sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
4653SQLITE_API void SQLITE_STDCALL sqlite3_result_value(sqlite3_context*, sqlite3_value*);
4654SQLITE_API void SQLITE_STDCALL sqlite3_result_zeroblob(sqlite3_context*, int n);
4655SQLITE_API int SQLITE_STDCALL sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n);
4656
4657/*
4658** CAPI3REF: Define New Collating Sequences
4659** METHOD: sqlite3
4660**
4661** ^These functions add, remove, or modify a [collation] associated
4662** with the [database connection] specified as the first argument.
4663**
4664** ^The name of the collation is a UTF-8 string
4665** for sqlite3_create_collation() and sqlite3_create_collation_v2()
4666** and a UTF-16 string in native byte order for sqlite3_create_collation16().
4667** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
4668** considered to be the same name.
4669**
4670** ^(The third argument (eTextRep) must be one of the constants:
4671** <ul>
4672** <li> [SQLITE_UTF8],
4673** <li> [SQLITE_UTF16LE],
4674** <li> [SQLITE_UTF16BE],
4675** <li> [SQLITE_UTF16], or
4676** <li> [SQLITE_UTF16_ALIGNED].
4677** </ul>)^
4678** ^The eTextRep argument determines the encoding of strings passed
4679** to the collating function callback, xCallback.
4680** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
4681** force strings to be UTF16 with native byte order.
4682** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
4683** on an even byte address.
4684**
4685** ^The fourth argument, pArg, is an application data pointer that is passed
4686** through as the first argument to the collating function callback.
4687**
4688** ^The fifth argument, xCallback, is a pointer to the collating function.
4689** ^Multiple collating functions can be registered using the same name but
4690** with different eTextRep parameters and SQLite will use whichever
4691** function requires the least amount of data transformation.
4692** ^If the xCallback argument is NULL then the collating function is
4693** deleted.  ^When all collating functions having the same name are deleted,
4694** that collation is no longer usable.
4695**
4696** ^The collating function callback is invoked with a copy of the pArg
4697** application data pointer and with two strings in the encoding specified
4698** by the eTextRep argument.  The collating function must return an
4699** integer that is negative, zero, or positive
4700** if the first string is less than, equal to, or greater than the second,
4701** respectively.  A collating function must always return the same answer
4702** given the same inputs.  If two or more collating functions are registered
4703** to the same collation name (using different eTextRep values) then all
4704** must give an equivalent answer when invoked with equivalent strings.
4705** The collating function must obey the following properties for all
4706** strings A, B, and C:
4707**
4708** <ol>
4709** <li> If A==B then B==A.
4710** <li> If A==B and B==C then A==C.
4711** <li> If A&lt;B THEN B&gt;A.
4712** <li> If A&lt;B and B&lt;C then A&lt;C.
4713** </ol>
4714**
4715** If a collating function fails any of the above constraints and that
4716** collating function is  registered and used, then the behavior of SQLite
4717** is undefined.
4718**
4719** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
4720** with the addition that the xDestroy callback is invoked on pArg when
4721** the collating function is deleted.
4722** ^Collating functions are deleted when they are overridden by later
4723** calls to the collation creation functions or when the
4724** [database connection] is closed using [sqlite3_close()].
4725**
4726** ^The xDestroy callback is <u>not</u> called if the
4727** sqlite3_create_collation_v2() function fails.  Applications that invoke
4728** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
4729** check the return code and dispose of the application data pointer
4730** themselves rather than expecting SQLite to deal with it for them.
4731** This is different from every other SQLite interface.  The inconsistency
4732** is unfortunate but cannot be changed without breaking backwards
4733** compatibility.
4734**
4735** See also:  [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
4736*/
4737SQLITE_API int SQLITE_STDCALL sqlite3_create_collation(
4738  sqlite3*,
4739  const char *zName,
4740  int eTextRep,
4741  void *pArg,
4742  int(*xCompare)(void*,int,const void*,int,const void*)
4743);
4744SQLITE_API int SQLITE_STDCALL sqlite3_create_collation_v2(
4745  sqlite3*,
4746  const char *zName,
4747  int eTextRep,
4748  void *pArg,
4749  int(*xCompare)(void*,int,const void*,int,const void*),
4750  void(*xDestroy)(void*)
4751);
4752SQLITE_API int SQLITE_STDCALL sqlite3_create_collation16(
4753  sqlite3*,
4754  const void *zName,
4755  int eTextRep,
4756  void *pArg,
4757  int(*xCompare)(void*,int,const void*,int,const void*)
4758);
4759
4760/*
4761** CAPI3REF: Collation Needed Callbacks
4762** METHOD: sqlite3
4763**
4764** ^To avoid having to register all collation sequences before a database
4765** can be used, a single callback function may be registered with the
4766** [database connection] to be invoked whenever an undefined collation
4767** sequence is required.
4768**
4769** ^If the function is registered using the sqlite3_collation_needed() API,
4770** then it is passed the names of undefined collation sequences as strings
4771** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
4772** the names are passed as UTF-16 in machine native byte order.
4773** ^A call to either function replaces the existing collation-needed callback.
4774**
4775** ^(When the callback is invoked, the first argument passed is a copy
4776** of the second argument to sqlite3_collation_needed() or
4777** sqlite3_collation_needed16().  The second argument is the database
4778** connection.  The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
4779** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
4780** sequence function required.  The fourth parameter is the name of the
4781** required collation sequence.)^
4782**
4783** The callback function should register the desired collation using
4784** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
4785** [sqlite3_create_collation_v2()].
4786*/
4787SQLITE_API int SQLITE_STDCALL sqlite3_collation_needed(
4788  sqlite3*,
4789  void*,
4790  void(*)(void*,sqlite3*,int eTextRep,const char*)
4791);
4792SQLITE_API int SQLITE_STDCALL sqlite3_collation_needed16(
4793  sqlite3*,
4794  void*,
4795  void(*)(void*,sqlite3*,int eTextRep,const void*)
4796);
4797
4798#ifdef SQLITE_HAS_CODEC
4799/*
4800** Specify the key for an encrypted database.  This routine should be
4801** called right after sqlite3_open().
4802**
4803** The code to implement this API is not available in the public release
4804** of SQLite.
4805*/
4806SQLITE_API int SQLITE_STDCALL sqlite3_key(
4807  sqlite3 *db,                   /* Database to be rekeyed */
4808  const void *pKey, int nKey     /* The key */
4809);
4810SQLITE_API int SQLITE_STDCALL sqlite3_key_v2(
4811  sqlite3 *db,                   /* Database to be rekeyed */
4812  const char *zDbName,           /* Name of the database */
4813  const void *pKey, int nKey     /* The key */
4814);
4815
4816/*
4817** Change the key on an open database.  If the current database is not
4818** encrypted, this routine will encrypt it.  If pNew==0 or nNew==0, the
4819** database is decrypted.
4820**
4821** The code to implement this API is not available in the public release
4822** of SQLite.
4823*/
4824SQLITE_API int SQLITE_STDCALL sqlite3_rekey(
4825  sqlite3 *db,                   /* Database to be rekeyed */
4826  const void *pKey, int nKey     /* The new key */
4827);
4828SQLITE_API int SQLITE_STDCALL sqlite3_rekey_v2(
4829  sqlite3 *db,                   /* Database to be rekeyed */
4830  const char *zDbName,           /* Name of the database */
4831  const void *pKey, int nKey     /* The new key */
4832);
4833
4834/*
4835** Specify the activation key for a SEE database.  Unless
4836** activated, none of the SEE routines will work.
4837*/
4838SQLITE_API void SQLITE_STDCALL sqlite3_activate_see(
4839  const char *zPassPhrase        /* Activation phrase */
4840);
4841#endif
4842
4843#ifdef SQLITE_ENABLE_CEROD
4844/*
4845** Specify the activation key for a CEROD database.  Unless
4846** activated, none of the CEROD routines will work.
4847*/
4848SQLITE_API void SQLITE_STDCALL sqlite3_activate_cerod(
4849  const char *zPassPhrase        /* Activation phrase */
4850);
4851#endif
4852
4853/*
4854** CAPI3REF: Suspend Execution For A Short Time
4855**
4856** The sqlite3_sleep() function causes the current thread to suspend execution
4857** for at least a number of milliseconds specified in its parameter.
4858**
4859** If the operating system does not support sleep requests with
4860** millisecond time resolution, then the time will be rounded up to
4861** the nearest second. The number of milliseconds of sleep actually
4862** requested from the operating system is returned.
4863**
4864** ^SQLite implements this interface by calling the xSleep()
4865** method of the default [sqlite3_vfs] object.  If the xSleep() method
4866** of the default VFS is not implemented correctly, or not implemented at
4867** all, then the behavior of sqlite3_sleep() may deviate from the description
4868** in the previous paragraphs.
4869*/
4870SQLITE_API int SQLITE_STDCALL sqlite3_sleep(int);
4871
4872/*
4873** CAPI3REF: Name Of The Folder Holding Temporary Files
4874**
4875** ^(If this global variable is made to point to a string which is
4876** the name of a folder (a.k.a. directory), then all temporary files
4877** created by SQLite when using a built-in [sqlite3_vfs | VFS]
4878** will be placed in that directory.)^  ^If this variable
4879** is a NULL pointer, then SQLite performs a search for an appropriate
4880** temporary file directory.
4881**
4882** Applications are strongly discouraged from using this global variable.
4883** It is required to set a temporary folder on Windows Runtime (WinRT).
4884** But for all other platforms, it is highly recommended that applications
4885** neither read nor write this variable.  This global variable is a relic
4886** that exists for backwards compatibility of legacy applications and should
4887** be avoided in new projects.
4888**
4889** It is not safe to read or modify this variable in more than one
4890** thread at a time.  It is not safe to read or modify this variable
4891** if a [database connection] is being used at the same time in a separate
4892** thread.
4893** It is intended that this variable be set once
4894** as part of process initialization and before any SQLite interface
4895** routines have been called and that this variable remain unchanged
4896** thereafter.
4897**
4898** ^The [temp_store_directory pragma] may modify this variable and cause
4899** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
4900** the [temp_store_directory pragma] always assumes that any string
4901** that this variable points to is held in memory obtained from
4902** [sqlite3_malloc] and the pragma may attempt to free that memory
4903** using [sqlite3_free].
4904** Hence, if this variable is modified directly, either it should be
4905** made NULL or made to point to memory obtained from [sqlite3_malloc]
4906** or else the use of the [temp_store_directory pragma] should be avoided.
4907** Except when requested by the [temp_store_directory pragma], SQLite
4908** does not free the memory that sqlite3_temp_directory points to.  If
4909** the application wants that memory to be freed, it must do
4910** so itself, taking care to only do so after all [database connection]
4911** objects have been destroyed.
4912**
4913** <b>Note to Windows Runtime users:</b>  The temporary directory must be set
4914** prior to calling [sqlite3_open] or [sqlite3_open_v2].  Otherwise, various
4915** features that require the use of temporary files may fail.  Here is an
4916** example of how to do this using C++ with the Windows Runtime:
4917**
4918** <blockquote><pre>
4919** LPCWSTR zPath = Windows::Storage::ApplicationData::Current->
4920** &nbsp;     TemporaryFolder->Path->Data();
4921** char zPathBuf&#91;MAX_PATH + 1&#93;;
4922** memset(zPathBuf, 0, sizeof(zPathBuf));
4923** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),
4924** &nbsp;     NULL, NULL);
4925** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);
4926** </pre></blockquote>
4927*/
4928SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory;
4929
4930/*
4931** CAPI3REF: Name Of The Folder Holding Database Files
4932**
4933** ^(If this global variable is made to point to a string which is
4934** the name of a folder (a.k.a. directory), then all database files
4935** specified with a relative pathname and created or accessed by
4936** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed
4937** to be relative to that directory.)^ ^If this variable is a NULL
4938** pointer, then SQLite assumes that all database files specified
4939** with a relative pathname are relative to the current directory
4940** for the process.  Only the windows VFS makes use of this global
4941** variable; it is ignored by the unix VFS.
4942**
4943** Changing the value of this variable while a database connection is
4944** open can result in a corrupt database.
4945**
4946** It is not safe to read or modify this variable in more than one
4947** thread at a time.  It is not safe to read or modify this variable
4948** if a [database connection] is being used at the same time in a separate
4949** thread.
4950** It is intended that this variable be set once
4951** as part of process initialization and before any SQLite interface
4952** routines have been called and that this variable remain unchanged
4953** thereafter.
4954**
4955** ^The [data_store_directory pragma] may modify this variable and cause
4956** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
4957** the [data_store_directory pragma] always assumes that any string
4958** that this variable points to is held in memory obtained from
4959** [sqlite3_malloc] and the pragma may attempt to free that memory
4960** using [sqlite3_free].
4961** Hence, if this variable is modified directly, either it should be
4962** made NULL or made to point to memory obtained from [sqlite3_malloc]
4963** or else the use of the [data_store_directory pragma] should be avoided.
4964*/
4965SQLITE_API SQLITE_EXTERN char *sqlite3_data_directory;
4966
4967/*
4968** CAPI3REF: Test For Auto-Commit Mode
4969** KEYWORDS: {autocommit mode}
4970** METHOD: sqlite3
4971**
4972** ^The sqlite3_get_autocommit() interface returns non-zero or
4973** zero if the given database connection is or is not in autocommit mode,
4974** respectively.  ^Autocommit mode is on by default.
4975** ^Autocommit mode is disabled by a [BEGIN] statement.
4976** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
4977**
4978** If certain kinds of errors occur on a statement within a multi-statement
4979** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
4980** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
4981** transaction might be rolled back automatically.  The only way to
4982** find out whether SQLite automatically rolled back the transaction after
4983** an error is to use this function.
4984**
4985** If another thread changes the autocommit status of the database
4986** connection while this routine is running, then the return value
4987** is undefined.
4988*/
4989SQLITE_API int SQLITE_STDCALL sqlite3_get_autocommit(sqlite3*);
4990
4991/*
4992** CAPI3REF: Find The Database Handle Of A Prepared Statement
4993** METHOD: sqlite3_stmt
4994**
4995** ^The sqlite3_db_handle interface returns the [database connection] handle
4996** to which a [prepared statement] belongs.  ^The [database connection]
4997** returned by sqlite3_db_handle is the same [database connection]
4998** that was the first argument
4999** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
5000** create the statement in the first place.
5001*/
5002SQLITE_API sqlite3 *SQLITE_STDCALL sqlite3_db_handle(sqlite3_stmt*);
5003
5004/*
5005** CAPI3REF: Return The Filename For A Database Connection
5006** METHOD: sqlite3
5007**
5008** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename
5009** associated with database N of connection D.  ^The main database file
5010** has the name "main".  If there is no attached database N on the database
5011** connection D, or if database N is a temporary or in-memory database, then
5012** a NULL pointer is returned.
5013**
5014** ^The filename returned by this function is the output of the
5015** xFullPathname method of the [VFS].  ^In other words, the filename
5016** will be an absolute pathname, even if the filename used
5017** to open the database originally was a URI or relative pathname.
5018*/
5019SQLITE_API const char *SQLITE_STDCALL sqlite3_db_filename(sqlite3 *db, const char *zDbName);
5020
5021/*
5022** CAPI3REF: Determine if a database is read-only
5023** METHOD: sqlite3
5024**
5025** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N
5026** of connection D is read-only, 0 if it is read/write, or -1 if N is not
5027** the name of a database on connection D.
5028*/
5029SQLITE_API int SQLITE_STDCALL sqlite3_db_readonly(sqlite3 *db, const char *zDbName);
5030
5031/*
5032** CAPI3REF: Find the next prepared statement
5033** METHOD: sqlite3
5034**
5035** ^This interface returns a pointer to the next [prepared statement] after
5036** pStmt associated with the [database connection] pDb.  ^If pStmt is NULL
5037** then this interface returns a pointer to the first prepared statement
5038** associated with the database connection pDb.  ^If no prepared statement
5039** satisfies the conditions of this routine, it returns NULL.
5040**
5041** The [database connection] pointer D in a call to
5042** [sqlite3_next_stmt(D,S)] must refer to an open database
5043** connection and in particular must not be a NULL pointer.
5044*/
5045SQLITE_API sqlite3_stmt *SQLITE_STDCALL sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
5046
5047/*
5048** CAPI3REF: Commit And Rollback Notification Callbacks
5049** METHOD: sqlite3
5050**
5051** ^The sqlite3_commit_hook() interface registers a callback
5052** function to be invoked whenever a transaction is [COMMIT | committed].
5053** ^Any callback set by a previous call to sqlite3_commit_hook()
5054** for the same database connection is overridden.
5055** ^The sqlite3_rollback_hook() interface registers a callback
5056** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
5057** ^Any callback set by a previous call to sqlite3_rollback_hook()
5058** for the same database connection is overridden.
5059** ^The pArg argument is passed through to the callback.
5060** ^If the callback on a commit hook function returns non-zero,
5061** then the commit is converted into a rollback.
5062**
5063** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
5064** return the P argument from the previous call of the same function
5065** on the same [database connection] D, or NULL for
5066** the first call for each function on D.
5067**
5068** The commit and rollback hook callbacks are not reentrant.
5069** The callback implementation must not do anything that will modify
5070** the database connection that invoked the callback.  Any actions
5071** to modify the database connection must be deferred until after the
5072** completion of the [sqlite3_step()] call that triggered the commit
5073** or rollback hook in the first place.
5074** Note that running any other SQL statements, including SELECT statements,
5075** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
5076** the database connections for the meaning of "modify" in this paragraph.
5077**
5078** ^Registering a NULL function disables the callback.
5079**
5080** ^When the commit hook callback routine returns zero, the [COMMIT]
5081** operation is allowed to continue normally.  ^If the commit hook
5082** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
5083** ^The rollback hook is invoked on a rollback that results from a commit
5084** hook returning non-zero, just as it would be with any other rollback.
5085**
5086** ^For the purposes of this API, a transaction is said to have been
5087** rolled back if an explicit "ROLLBACK" statement is executed, or
5088** an error or constraint causes an implicit rollback to occur.
5089** ^The rollback callback is not invoked if a transaction is
5090** automatically rolled back because the database connection is closed.
5091**
5092** See also the [sqlite3_update_hook()] interface.
5093*/
5094SQLITE_API void *SQLITE_STDCALL sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
5095SQLITE_API void *SQLITE_STDCALL sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
5096
5097/*
5098** CAPI3REF: Data Change Notification Callbacks
5099** METHOD: sqlite3
5100**
5101** ^The sqlite3_update_hook() interface registers a callback function
5102** with the [database connection] identified by the first argument
5103** to be invoked whenever a row is updated, inserted or deleted in
5104** a rowid table.
5105** ^Any callback set by a previous call to this function
5106** for the same database connection is overridden.
5107**
5108** ^The second argument is a pointer to the function to invoke when a
5109** row is updated, inserted or deleted in a rowid table.
5110** ^The first argument to the callback is a copy of the third argument
5111** to sqlite3_update_hook().
5112** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
5113** or [SQLITE_UPDATE], depending on the operation that caused the callback
5114** to be invoked.
5115** ^The third and fourth arguments to the callback contain pointers to the
5116** database and table name containing the affected row.
5117** ^The final callback parameter is the [rowid] of the row.
5118** ^In the case of an update, this is the [rowid] after the update takes place.
5119**
5120** ^(The update hook is not invoked when internal system tables are
5121** modified (i.e. sqlite_master and sqlite_sequence).)^
5122** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified.
5123**
5124** ^In the current implementation, the update hook
5125** is not invoked when duplication rows are deleted because of an
5126** [ON CONFLICT | ON CONFLICT REPLACE] clause.  ^Nor is the update hook
5127** invoked when rows are deleted using the [truncate optimization].
5128** The exceptions defined in this paragraph might change in a future
5129** release of SQLite.
5130**
5131** The update hook implementation must not do anything that will modify
5132** the database connection that invoked the update hook.  Any actions
5133** to modify the database connection must be deferred until after the
5134** completion of the [sqlite3_step()] call that triggered the update hook.
5135** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
5136** database connections for the meaning of "modify" in this paragraph.
5137**
5138** ^The sqlite3_update_hook(D,C,P) function
5139** returns the P argument from the previous call
5140** on the same [database connection] D, or NULL for
5141** the first call on D.
5142**
5143** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()]
5144** interfaces.
5145*/
5146SQLITE_API void *SQLITE_STDCALL sqlite3_update_hook(
5147  sqlite3*,
5148  void(*)(void *,int ,char const *,char const *,sqlite3_int64),
5149  void*
5150);
5151
5152/*
5153** CAPI3REF: Enable Or Disable Shared Pager Cache
5154**
5155** ^(This routine enables or disables the sharing of the database cache
5156** and schema data structures between [database connection | connections]
5157** to the same database. Sharing is enabled if the argument is true
5158** and disabled if the argument is false.)^
5159**
5160** ^Cache sharing is enabled and disabled for an entire process.
5161** This is a change as of SQLite version 3.5.0. In prior versions of SQLite,
5162** sharing was enabled or disabled for each thread separately.
5163**
5164** ^(The cache sharing mode set by this interface effects all subsequent
5165** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
5166** Existing database connections continue use the sharing mode
5167** that was in effect at the time they were opened.)^
5168**
5169** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
5170** successfully.  An [error code] is returned otherwise.)^
5171**
5172** ^Shared cache is disabled by default. But this might change in
5173** future releases of SQLite.  Applications that care about shared
5174** cache setting should set it explicitly.
5175**
5176** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0
5177** and will always return SQLITE_MISUSE. On those systems,
5178** shared cache mode should be enabled per-database connection via
5179** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE].
5180**
5181** This interface is threadsafe on processors where writing a
5182** 32-bit integer is atomic.
5183**
5184** See Also:  [SQLite Shared-Cache Mode]
5185*/
5186SQLITE_API int SQLITE_STDCALL sqlite3_enable_shared_cache(int);
5187
5188/*
5189** CAPI3REF: Attempt To Free Heap Memory
5190**
5191** ^The sqlite3_release_memory() interface attempts to free N bytes
5192** of heap memory by deallocating non-essential memory allocations
5193** held by the database library.   Memory used to cache database
5194** pages to improve performance is an example of non-essential memory.
5195** ^sqlite3_release_memory() returns the number of bytes actually freed,
5196** which might be more or less than the amount requested.
5197** ^The sqlite3_release_memory() routine is a no-op returning zero
5198** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
5199**
5200** See also: [sqlite3_db_release_memory()]
5201*/
5202SQLITE_API int SQLITE_STDCALL sqlite3_release_memory(int);
5203
5204/*
5205** CAPI3REF: Free Memory Used By A Database Connection
5206** METHOD: sqlite3
5207**
5208** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap
5209** memory as possible from database connection D. Unlike the
5210** [sqlite3_release_memory()] interface, this interface is in effect even
5211** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
5212** omitted.
5213**
5214** See also: [sqlite3_release_memory()]
5215*/
5216SQLITE_API int SQLITE_STDCALL sqlite3_db_release_memory(sqlite3*);
5217
5218/*
5219** CAPI3REF: Impose A Limit On Heap Size
5220**
5221** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
5222** soft limit on the amount of heap memory that may be allocated by SQLite.
5223** ^SQLite strives to keep heap memory utilization below the soft heap
5224** limit by reducing the number of pages held in the page cache
5225** as heap memory usages approaches the limit.
5226** ^The soft heap limit is "soft" because even though SQLite strives to stay
5227** below the limit, it will exceed the limit rather than generate
5228** an [SQLITE_NOMEM] error.  In other words, the soft heap limit
5229** is advisory only.
5230**
5231** ^The return value from sqlite3_soft_heap_limit64() is the size of
5232** the soft heap limit prior to the call, or negative in the case of an
5233** error.  ^If the argument N is negative
5234** then no change is made to the soft heap limit.  Hence, the current
5235** size of the soft heap limit can be determined by invoking
5236** sqlite3_soft_heap_limit64() with a negative argument.
5237**
5238** ^If the argument N is zero then the soft heap limit is disabled.
5239**
5240** ^(The soft heap limit is not enforced in the current implementation
5241** if one or more of following conditions are true:
5242**
5243** <ul>
5244** <li> The soft heap limit is set to zero.
5245** <li> Memory accounting is disabled using a combination of the
5246**      [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
5247**      the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
5248** <li> An alternative page cache implementation is specified using
5249**      [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
5250** <li> The page cache allocates from its own memory pool supplied
5251**      by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
5252**      from the heap.
5253** </ul>)^
5254**
5255** Beginning with SQLite version 3.7.3, the soft heap limit is enforced
5256** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT]
5257** compile-time option is invoked.  With [SQLITE_ENABLE_MEMORY_MANAGEMENT],
5258** the soft heap limit is enforced on every memory allocation.  Without
5259** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced
5260** when memory is allocated by the page cache.  Testing suggests that because
5261** the page cache is the predominate memory user in SQLite, most
5262** applications will achieve adequate soft heap limit enforcement without
5263** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT].
5264**
5265** The circumstances under which SQLite will enforce the soft heap limit may
5266** changes in future releases of SQLite.
5267*/
5268SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_soft_heap_limit64(sqlite3_int64 N);
5269
5270/*
5271** CAPI3REF: Deprecated Soft Heap Limit Interface
5272** DEPRECATED
5273**
5274** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
5275** interface.  This routine is provided for historical compatibility
5276** only.  All new applications should use the
5277** [sqlite3_soft_heap_limit64()] interface rather than this one.
5278*/
5279SQLITE_API SQLITE_DEPRECATED void SQLITE_STDCALL sqlite3_soft_heap_limit(int N);
5280
5281
5282/*
5283** CAPI3REF: Extract Metadata About A Column Of A Table
5284** METHOD: sqlite3
5285**
5286** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns
5287** information about column C of table T in database D
5288** on [database connection] X.)^  ^The sqlite3_table_column_metadata()
5289** interface returns SQLITE_OK and fills in the non-NULL pointers in
5290** the final five arguments with appropriate values if the specified
5291** column exists.  ^The sqlite3_table_column_metadata() interface returns
5292** SQLITE_ERROR and if the specified column does not exist.
5293** ^If the column-name parameter to sqlite3_table_column_metadata() is a
5294** NULL pointer, then this routine simply checks for the existance of the
5295** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it
5296** does not.
5297**
5298** ^The column is identified by the second, third and fourth parameters to
5299** this function. ^(The second parameter is either the name of the database
5300** (i.e. "main", "temp", or an attached database) containing the specified
5301** table or NULL.)^ ^If it is NULL, then all attached databases are searched
5302** for the table using the same algorithm used by the database engine to
5303** resolve unqualified table references.
5304**
5305** ^The third and fourth parameters to this function are the table and column
5306** name of the desired column, respectively.
5307**
5308** ^Metadata is returned by writing to the memory locations passed as the 5th
5309** and subsequent parameters to this function. ^Any of these arguments may be
5310** NULL, in which case the corresponding element of metadata is omitted.
5311**
5312** ^(<blockquote>
5313** <table border="1">
5314** <tr><th> Parameter <th> Output<br>Type <th>  Description
5315**
5316** <tr><td> 5th <td> const char* <td> Data type
5317** <tr><td> 6th <td> const char* <td> Name of default collation sequence
5318** <tr><td> 7th <td> int         <td> True if column has a NOT NULL constraint
5319** <tr><td> 8th <td> int         <td> True if column is part of the PRIMARY KEY
5320** <tr><td> 9th <td> int         <td> True if column is [AUTOINCREMENT]
5321** </table>
5322** </blockquote>)^
5323**
5324** ^The memory pointed to by the character pointers returned for the
5325** declaration type and collation sequence is valid until the next
5326** call to any SQLite API function.
5327**
5328** ^If the specified table is actually a view, an [error code] is returned.
5329**
5330** ^If the specified column is "rowid", "oid" or "_rowid_" and the table
5331** is not a [WITHOUT ROWID] table and an
5332** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
5333** parameters are set for the explicitly declared column. ^(If there is no
5334** [INTEGER PRIMARY KEY] column, then the outputs
5335** for the [rowid] are set as follows:
5336**
5337** <pre>
5338**     data type: "INTEGER"
5339**     collation sequence: "BINARY"
5340**     not null: 0
5341**     primary key: 1
5342**     auto increment: 0
5343** </pre>)^
5344**
5345** ^This function causes all database schemas to be read from disk and
5346** parsed, if that has not already been done, and returns an error if
5347** any errors are encountered while loading the schema.
5348*/
5349SQLITE_API int SQLITE_STDCALL sqlite3_table_column_metadata(
5350  sqlite3 *db,                /* Connection handle */
5351  const char *zDbName,        /* Database name or NULL */
5352  const char *zTableName,     /* Table name */
5353  const char *zColumnName,    /* Column name */
5354  char const **pzDataType,    /* OUTPUT: Declared data type */
5355  char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
5356  int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
5357  int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
5358  int *pAutoinc               /* OUTPUT: True if column is auto-increment */
5359);
5360
5361/*
5362** CAPI3REF: Load An Extension
5363** METHOD: sqlite3
5364**
5365** ^This interface loads an SQLite extension library from the named file.
5366**
5367** ^The sqlite3_load_extension() interface attempts to load an
5368** [SQLite extension] library contained in the file zFile.  If
5369** the file cannot be loaded directly, attempts are made to load
5370** with various operating-system specific extensions added.
5371** So for example, if "samplelib" cannot be loaded, then names like
5372** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might
5373** be tried also.
5374**
5375** ^The entry point is zProc.
5376** ^(zProc may be 0, in which case SQLite will try to come up with an
5377** entry point name on its own.  It first tries "sqlite3_extension_init".
5378** If that does not work, it constructs a name "sqlite3_X_init" where the
5379** X is consists of the lower-case equivalent of all ASCII alphabetic
5380** characters in the filename from the last "/" to the first following
5381** "." and omitting any initial "lib".)^
5382** ^The sqlite3_load_extension() interface returns
5383** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
5384** ^If an error occurs and pzErrMsg is not 0, then the
5385** [sqlite3_load_extension()] interface shall attempt to
5386** fill *pzErrMsg with error message text stored in memory
5387** obtained from [sqlite3_malloc()]. The calling function
5388** should free this memory by calling [sqlite3_free()].
5389**
5390** ^Extension loading must be enabled using
5391** [sqlite3_enable_load_extension()] prior to calling this API,
5392** otherwise an error will be returned.
5393**
5394** See also the [load_extension() SQL function].
5395*/
5396SQLITE_API int SQLITE_STDCALL sqlite3_load_extension(
5397  sqlite3 *db,          /* Load the extension into this database connection */
5398  const char *zFile,    /* Name of the shared library containing extension */
5399  const char *zProc,    /* Entry point.  Derived from zFile if 0 */
5400  char **pzErrMsg       /* Put error message here if not 0 */
5401);
5402
5403/*
5404** CAPI3REF: Enable Or Disable Extension Loading
5405** METHOD: sqlite3
5406**
5407** ^So as not to open security holes in older applications that are
5408** unprepared to deal with [extension loading], and as a means of disabling
5409** [extension loading] while evaluating user-entered SQL, the following API
5410** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
5411**
5412** ^Extension loading is off by default.
5413** ^Call the sqlite3_enable_load_extension() routine with onoff==1
5414** to turn extension loading on and call it with onoff==0 to turn
5415** it back off again.
5416*/
5417SQLITE_API int SQLITE_STDCALL sqlite3_enable_load_extension(sqlite3 *db, int onoff);
5418
5419/*
5420** CAPI3REF: Automatically Load Statically Linked Extensions
5421**
5422** ^This interface causes the xEntryPoint() function to be invoked for
5423** each new [database connection] that is created.  The idea here is that
5424** xEntryPoint() is the entry point for a statically linked [SQLite extension]
5425** that is to be automatically loaded into all new database connections.
5426**
5427** ^(Even though the function prototype shows that xEntryPoint() takes
5428** no arguments and returns void, SQLite invokes xEntryPoint() with three
5429** arguments and expects and integer result as if the signature of the
5430** entry point where as follows:
5431**
5432** <blockquote><pre>
5433** &nbsp;  int xEntryPoint(
5434** &nbsp;    sqlite3 *db,
5435** &nbsp;    const char **pzErrMsg,
5436** &nbsp;    const struct sqlite3_api_routines *pThunk
5437** &nbsp;  );
5438** </pre></blockquote>)^
5439**
5440** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
5441** point to an appropriate error message (obtained from [sqlite3_mprintf()])
5442** and return an appropriate [error code].  ^SQLite ensures that *pzErrMsg
5443** is NULL before calling the xEntryPoint().  ^SQLite will invoke
5444** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns.  ^If any
5445** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
5446** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
5447**
5448** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
5449** on the list of automatic extensions is a harmless no-op. ^No entry point
5450** will be called more than once for each database connection that is opened.
5451**
5452** See also: [sqlite3_reset_auto_extension()]
5453** and [sqlite3_cancel_auto_extension()]
5454*/
5455SQLITE_API int SQLITE_STDCALL sqlite3_auto_extension(void (*xEntryPoint)(void));
5456
5457/*
5458** CAPI3REF: Cancel Automatic Extension Loading
5459**
5460** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the
5461** initialization routine X that was registered using a prior call to
5462** [sqlite3_auto_extension(X)].  ^The [sqlite3_cancel_auto_extension(X)]
5463** routine returns 1 if initialization routine X was successfully
5464** unregistered and it returns 0 if X was not on the list of initialization
5465** routines.
5466*/
5467SQLITE_API int SQLITE_STDCALL sqlite3_cancel_auto_extension(void (*xEntryPoint)(void));
5468
5469/*
5470** CAPI3REF: Reset Automatic Extension Loading
5471**
5472** ^This interface disables all automatic extensions previously
5473** registered using [sqlite3_auto_extension()].
5474*/
5475SQLITE_API void SQLITE_STDCALL sqlite3_reset_auto_extension(void);
5476
5477/*
5478** The interface to the virtual-table mechanism is currently considered
5479** to be experimental.  The interface might change in incompatible ways.
5480** If this is a problem for you, do not use the interface at this time.
5481**
5482** When the virtual-table mechanism stabilizes, we will declare the
5483** interface fixed, support it indefinitely, and remove this comment.
5484*/
5485
5486/*
5487** Structures used by the virtual table interface
5488*/
5489typedef struct sqlite3_vtab sqlite3_vtab;
5490typedef struct sqlite3_index_info sqlite3_index_info;
5491typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
5492typedef struct sqlite3_module sqlite3_module;
5493
5494/*
5495** CAPI3REF: Virtual Table Object
5496** KEYWORDS: sqlite3_module {virtual table module}
5497**
5498** This structure, sometimes called a "virtual table module",
5499** defines the implementation of a [virtual tables].
5500** This structure consists mostly of methods for the module.
5501**
5502** ^A virtual table module is created by filling in a persistent
5503** instance of this structure and passing a pointer to that instance
5504** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
5505** ^The registration remains valid until it is replaced by a different
5506** module or until the [database connection] closes.  The content
5507** of this structure must not change while it is registered with
5508** any database connection.
5509*/
5510struct sqlite3_module {
5511  int iVersion;
5512  int (*xCreate)(sqlite3*, void *pAux,
5513               int argc, const char *const*argv,
5514               sqlite3_vtab **ppVTab, char**);
5515  int (*xConnect)(sqlite3*, void *pAux,
5516               int argc, const char *const*argv,
5517               sqlite3_vtab **ppVTab, char**);
5518  int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
5519  int (*xDisconnect)(sqlite3_vtab *pVTab);
5520  int (*xDestroy)(sqlite3_vtab *pVTab);
5521  int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
5522  int (*xClose)(sqlite3_vtab_cursor*);
5523  int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
5524                int argc, sqlite3_value **argv);
5525  int (*xNext)(sqlite3_vtab_cursor*);
5526  int (*xEof)(sqlite3_vtab_cursor*);
5527  int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
5528  int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
5529  int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
5530  int (*xBegin)(sqlite3_vtab *pVTab);
5531  int (*xSync)(sqlite3_vtab *pVTab);
5532  int (*xCommit)(sqlite3_vtab *pVTab);
5533  int (*xRollback)(sqlite3_vtab *pVTab);
5534  int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
5535                       void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
5536                       void **ppArg);
5537  int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
5538  /* The methods above are in version 1 of the sqlite_module object. Those
5539  ** below are for version 2 and greater. */
5540  int (*xSavepoint)(sqlite3_vtab *pVTab, int);
5541  int (*xRelease)(sqlite3_vtab *pVTab, int);
5542  int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
5543};
5544
5545/*
5546** CAPI3REF: Virtual Table Indexing Information
5547** KEYWORDS: sqlite3_index_info
5548**
5549** The sqlite3_index_info structure and its substructures is used as part
5550** of the [virtual table] interface to
5551** pass information into and receive the reply from the [xBestIndex]
5552** method of a [virtual table module].  The fields under **Inputs** are the
5553** inputs to xBestIndex and are read-only.  xBestIndex inserts its
5554** results into the **Outputs** fields.
5555**
5556** ^(The aConstraint[] array records WHERE clause constraints of the form:
5557**
5558** <blockquote>column OP expr</blockquote>
5559**
5560** where OP is =, &lt;, &lt;=, &gt;, or &gt;=.)^  ^(The particular operator is
5561** stored in aConstraint[].op using one of the
5562** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
5563** ^(The index of the column is stored in
5564** aConstraint[].iColumn.)^  ^(aConstraint[].usable is TRUE if the
5565** expr on the right-hand side can be evaluated (and thus the constraint
5566** is usable) and false if it cannot.)^
5567**
5568** ^The optimizer automatically inverts terms of the form "expr OP column"
5569** and makes other simplifications to the WHERE clause in an attempt to
5570** get as many WHERE clause terms into the form shown above as possible.
5571** ^The aConstraint[] array only reports WHERE clause terms that are
5572** relevant to the particular virtual table being queried.
5573**
5574** ^Information about the ORDER BY clause is stored in aOrderBy[].
5575** ^Each term of aOrderBy records a column of the ORDER BY clause.
5576**
5577** The [xBestIndex] method must fill aConstraintUsage[] with information
5578** about what parameters to pass to xFilter.  ^If argvIndex>0 then
5579** the right-hand side of the corresponding aConstraint[] is evaluated
5580** and becomes the argvIndex-th entry in argv.  ^(If aConstraintUsage[].omit
5581** is true, then the constraint is assumed to be fully handled by the
5582** virtual table and is not checked again by SQLite.)^
5583**
5584** ^The idxNum and idxPtr values are recorded and passed into the
5585** [xFilter] method.
5586** ^[sqlite3_free()] is used to free idxPtr if and only if
5587** needToFreeIdxPtr is true.
5588**
5589** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
5590** the correct order to satisfy the ORDER BY clause so that no separate
5591** sorting step is required.
5592**
5593** ^The estimatedCost value is an estimate of the cost of a particular
5594** strategy. A cost of N indicates that the cost of the strategy is similar
5595** to a linear scan of an SQLite table with N rows. A cost of log(N)
5596** indicates that the expense of the operation is similar to that of a
5597** binary search on a unique indexed field of an SQLite table with N rows.
5598**
5599** ^The estimatedRows value is an estimate of the number of rows that
5600** will be returned by the strategy.
5601**
5602** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info
5603** structure for SQLite version 3.8.2. If a virtual table extension is
5604** used with an SQLite version earlier than 3.8.2, the results of attempting
5605** to read or write the estimatedRows field are undefined (but are likely
5606** to included crashing the application). The estimatedRows field should
5607** therefore only be used if [sqlite3_libversion_number()] returns a
5608** value greater than or equal to 3008002.
5609*/
5610struct sqlite3_index_info {
5611  /* Inputs */
5612  int nConstraint;           /* Number of entries in aConstraint */
5613  struct sqlite3_index_constraint {
5614     int iColumn;              /* Column on left-hand side of constraint */
5615     unsigned char op;         /* Constraint operator */
5616     unsigned char usable;     /* True if this constraint is usable */
5617     int iTermOffset;          /* Used internally - xBestIndex should ignore */
5618  } *aConstraint;            /* Table of WHERE clause constraints */
5619  int nOrderBy;              /* Number of terms in the ORDER BY clause */
5620  struct sqlite3_index_orderby {
5621     int iColumn;              /* Column number */
5622     unsigned char desc;       /* True for DESC.  False for ASC. */
5623  } *aOrderBy;               /* The ORDER BY clause */
5624  /* Outputs */
5625  struct sqlite3_index_constraint_usage {
5626    int argvIndex;           /* if >0, constraint is part of argv to xFilter */
5627    unsigned char omit;      /* Do not code a test for this constraint */
5628  } *aConstraintUsage;
5629  int idxNum;                /* Number used to identify the index */
5630  char *idxStr;              /* String, possibly obtained from sqlite3_malloc */
5631  int needToFreeIdxStr;      /* Free idxStr using sqlite3_free() if true */
5632  int orderByConsumed;       /* True if output is already ordered */
5633  double estimatedCost;           /* Estimated cost of using this index */
5634  /* Fields below are only available in SQLite 3.8.2 and later */
5635  sqlite3_int64 estimatedRows;    /* Estimated number of rows returned */
5636};
5637
5638/*
5639** CAPI3REF: Virtual Table Constraint Operator Codes
5640**
5641** These macros defined the allowed values for the
5642** [sqlite3_index_info].aConstraint[].op field.  Each value represents
5643** an operator that is part of a constraint term in the wHERE clause of
5644** a query that uses a [virtual table].
5645*/
5646#define SQLITE_INDEX_CONSTRAINT_EQ    2
5647#define SQLITE_INDEX_CONSTRAINT_GT    4
5648#define SQLITE_INDEX_CONSTRAINT_LE    8
5649#define SQLITE_INDEX_CONSTRAINT_LT    16
5650#define SQLITE_INDEX_CONSTRAINT_GE    32
5651#define SQLITE_INDEX_CONSTRAINT_MATCH 64
5652
5653/*
5654** CAPI3REF: Register A Virtual Table Implementation
5655** METHOD: sqlite3
5656**
5657** ^These routines are used to register a new [virtual table module] name.
5658** ^Module names must be registered before
5659** creating a new [virtual table] using the module and before using a
5660** preexisting [virtual table] for the module.
5661**
5662** ^The module name is registered on the [database connection] specified
5663** by the first parameter.  ^The name of the module is given by the
5664** second parameter.  ^The third parameter is a pointer to
5665** the implementation of the [virtual table module].   ^The fourth
5666** parameter is an arbitrary client data pointer that is passed through
5667** into the [xCreate] and [xConnect] methods of the virtual table module
5668** when a new virtual table is be being created or reinitialized.
5669**
5670** ^The sqlite3_create_module_v2() interface has a fifth parameter which
5671** is a pointer to a destructor for the pClientData.  ^SQLite will
5672** invoke the destructor function (if it is not NULL) when SQLite
5673** no longer needs the pClientData pointer.  ^The destructor will also
5674** be invoked if the call to sqlite3_create_module_v2() fails.
5675** ^The sqlite3_create_module()
5676** interface is equivalent to sqlite3_create_module_v2() with a NULL
5677** destructor.
5678*/
5679SQLITE_API int SQLITE_STDCALL sqlite3_create_module(
5680  sqlite3 *db,               /* SQLite connection to register module with */
5681  const char *zName,         /* Name of the module */
5682  const sqlite3_module *p,   /* Methods for the module */
5683  void *pClientData          /* Client data for xCreate/xConnect */
5684);
5685SQLITE_API int SQLITE_STDCALL sqlite3_create_module_v2(
5686  sqlite3 *db,               /* SQLite connection to register module with */
5687  const char *zName,         /* Name of the module */
5688  const sqlite3_module *p,   /* Methods for the module */
5689  void *pClientData,         /* Client data for xCreate/xConnect */
5690  void(*xDestroy)(void*)     /* Module destructor function */
5691);
5692
5693/*
5694** CAPI3REF: Virtual Table Instance Object
5695** KEYWORDS: sqlite3_vtab
5696**
5697** Every [virtual table module] implementation uses a subclass
5698** of this object to describe a particular instance
5699** of the [virtual table].  Each subclass will
5700** be tailored to the specific needs of the module implementation.
5701** The purpose of this superclass is to define certain fields that are
5702** common to all module implementations.
5703**
5704** ^Virtual tables methods can set an error message by assigning a
5705** string obtained from [sqlite3_mprintf()] to zErrMsg.  The method should
5706** take care that any prior string is freed by a call to [sqlite3_free()]
5707** prior to assigning a new string to zErrMsg.  ^After the error message
5708** is delivered up to the client application, the string will be automatically
5709** freed by sqlite3_free() and the zErrMsg field will be zeroed.
5710*/
5711struct sqlite3_vtab {
5712  const sqlite3_module *pModule;  /* The module for this virtual table */
5713  int nRef;                       /* Number of open cursors */
5714  char *zErrMsg;                  /* Error message from sqlite3_mprintf() */
5715  /* Virtual table implementations will typically add additional fields */
5716};
5717
5718/*
5719** CAPI3REF: Virtual Table Cursor Object
5720** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
5721**
5722** Every [virtual table module] implementation uses a subclass of the
5723** following structure to describe cursors that point into the
5724** [virtual table] and are used
5725** to loop through the virtual table.  Cursors are created using the
5726** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
5727** by the [sqlite3_module.xClose | xClose] method.  Cursors are used
5728** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
5729** of the module.  Each module implementation will define
5730** the content of a cursor structure to suit its own needs.
5731**
5732** This superclass exists in order to define fields of the cursor that
5733** are common to all implementations.
5734*/
5735struct sqlite3_vtab_cursor {
5736  sqlite3_vtab *pVtab;      /* Virtual table of this cursor */
5737  /* Virtual table implementations will typically add additional fields */
5738};
5739
5740/*
5741** CAPI3REF: Declare The Schema Of A Virtual Table
5742**
5743** ^The [xCreate] and [xConnect] methods of a
5744** [virtual table module] call this interface
5745** to declare the format (the names and datatypes of the columns) of
5746** the virtual tables they implement.
5747*/
5748SQLITE_API int SQLITE_STDCALL sqlite3_declare_vtab(sqlite3*, const char *zSQL);
5749
5750/*
5751** CAPI3REF: Overload A Function For A Virtual Table
5752** METHOD: sqlite3
5753**
5754** ^(Virtual tables can provide alternative implementations of functions
5755** using the [xFindFunction] method of the [virtual table module].
5756** But global versions of those functions
5757** must exist in order to be overloaded.)^
5758**
5759** ^(This API makes sure a global version of a function with a particular
5760** name and number of parameters exists.  If no such function exists
5761** before this API is called, a new function is created.)^  ^The implementation
5762** of the new function always causes an exception to be thrown.  So
5763** the new function is not good for anything by itself.  Its only
5764** purpose is to be a placeholder function that can be overloaded
5765** by a [virtual table].
5766*/
5767SQLITE_API int SQLITE_STDCALL sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
5768
5769/*
5770** The interface to the virtual-table mechanism defined above (back up
5771** to a comment remarkably similar to this one) is currently considered
5772** to be experimental.  The interface might change in incompatible ways.
5773** If this is a problem for you, do not use the interface at this time.
5774**
5775** When the virtual-table mechanism stabilizes, we will declare the
5776** interface fixed, support it indefinitely, and remove this comment.
5777*/
5778
5779/*
5780** CAPI3REF: A Handle To An Open BLOB
5781** KEYWORDS: {BLOB handle} {BLOB handles}
5782**
5783** An instance of this object represents an open BLOB on which
5784** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
5785** ^Objects of this type are created by [sqlite3_blob_open()]
5786** and destroyed by [sqlite3_blob_close()].
5787** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
5788** can be used to read or write small subsections of the BLOB.
5789** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
5790*/
5791typedef struct sqlite3_blob sqlite3_blob;
5792
5793/*
5794** CAPI3REF: Open A BLOB For Incremental I/O
5795** METHOD: sqlite3
5796** CONSTRUCTOR: sqlite3_blob
5797**
5798** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
5799** in row iRow, column zColumn, table zTable in database zDb;
5800** in other words, the same BLOB that would be selected by:
5801**
5802** <pre>
5803**     SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
5804** </pre>)^
5805**
5806** ^(Parameter zDb is not the filename that contains the database, but
5807** rather the symbolic name of the database. For attached databases, this is
5808** the name that appears after the AS keyword in the [ATTACH] statement.
5809** For the main database file, the database name is "main". For TEMP
5810** tables, the database name is "temp".)^
5811**
5812** ^If the flags parameter is non-zero, then the BLOB is opened for read
5813** and write access. ^If the flags parameter is zero, the BLOB is opened for
5814** read-only access.
5815**
5816** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored
5817** in *ppBlob. Otherwise an [error code] is returned and, unless the error
5818** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided
5819** the API is not misused, it is always safe to call [sqlite3_blob_close()]
5820** on *ppBlob after this function it returns.
5821**
5822** This function fails with SQLITE_ERROR if any of the following are true:
5823** <ul>
5824**   <li> ^(Database zDb does not exist)^,
5825**   <li> ^(Table zTable does not exist within database zDb)^,
5826**   <li> ^(Table zTable is a WITHOUT ROWID table)^,
5827**   <li> ^(Column zColumn does not exist)^,
5828**   <li> ^(Row iRow is not present in the table)^,
5829**   <li> ^(The specified column of row iRow contains a value that is not
5830**         a TEXT or BLOB value)^,
5831**   <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE
5832**         constraint and the blob is being opened for read/write access)^,
5833**   <li> ^([foreign key constraints | Foreign key constraints] are enabled,
5834**         column zColumn is part of a [child key] definition and the blob is
5835**         being opened for read/write access)^.
5836** </ul>
5837**
5838** ^Unless it returns SQLITE_MISUSE, this function sets the
5839** [database connection] error code and message accessible via
5840** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
5841**
5842**
5843** ^(If the row that a BLOB handle points to is modified by an
5844** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
5845** then the BLOB handle is marked as "expired".
5846** This is true if any column of the row is changed, even a column
5847** other than the one the BLOB handle is open on.)^
5848** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
5849** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
5850** ^(Changes written into a BLOB prior to the BLOB expiring are not
5851** rolled back by the expiration of the BLOB.  Such changes will eventually
5852** commit if the transaction continues to completion.)^
5853**
5854** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
5855** the opened blob.  ^The size of a blob may not be changed by this
5856** interface.  Use the [UPDATE] SQL command to change the size of a
5857** blob.
5858**
5859** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
5860** and the built-in [zeroblob] SQL function may be used to create a
5861** zero-filled blob to read or write using the incremental-blob interface.
5862**
5863** To avoid a resource leak, every open [BLOB handle] should eventually
5864** be released by a call to [sqlite3_blob_close()].
5865*/
5866SQLITE_API int SQLITE_STDCALL sqlite3_blob_open(
5867  sqlite3*,
5868  const char *zDb,
5869  const char *zTable,
5870  const char *zColumn,
5871  sqlite3_int64 iRow,
5872  int flags,
5873  sqlite3_blob **ppBlob
5874);
5875
5876/*
5877** CAPI3REF: Move a BLOB Handle to a New Row
5878** METHOD: sqlite3_blob
5879**
5880** ^This function is used to move an existing blob handle so that it points
5881** to a different row of the same database table. ^The new row is identified
5882** by the rowid value passed as the second argument. Only the row can be
5883** changed. ^The database, table and column on which the blob handle is open
5884** remain the same. Moving an existing blob handle to a new row can be
5885** faster than closing the existing handle and opening a new one.
5886**
5887** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
5888** it must exist and there must be either a blob or text value stored in
5889** the nominated column.)^ ^If the new row is not present in the table, or if
5890** it does not contain a blob or text value, or if another error occurs, an
5891** SQLite error code is returned and the blob handle is considered aborted.
5892** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
5893** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
5894** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
5895** always returns zero.
5896**
5897** ^This function sets the database handle error code and message.
5898*/
5899SQLITE_API int SQLITE_STDCALL sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
5900
5901/*
5902** CAPI3REF: Close A BLOB Handle
5903** DESTRUCTOR: sqlite3_blob
5904**
5905** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed
5906** unconditionally.  Even if this routine returns an error code, the
5907** handle is still closed.)^
5908**
5909** ^If the blob handle being closed was opened for read-write access, and if
5910** the database is in auto-commit mode and there are no other open read-write
5911** blob handles or active write statements, the current transaction is
5912** committed. ^If an error occurs while committing the transaction, an error
5913** code is returned and the transaction rolled back.
5914**
5915** Calling this function with an argument that is not a NULL pointer or an
5916** open blob handle results in undefined behaviour. ^Calling this routine
5917** with a null pointer (such as would be returned by a failed call to
5918** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function
5919** is passed a valid open blob handle, the values returned by the
5920** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning.
5921*/
5922SQLITE_API int SQLITE_STDCALL sqlite3_blob_close(sqlite3_blob *);
5923
5924/*
5925** CAPI3REF: Return The Size Of An Open BLOB
5926** METHOD: sqlite3_blob
5927**
5928** ^Returns the size in bytes of the BLOB accessible via the
5929** successfully opened [BLOB handle] in its only argument.  ^The
5930** incremental blob I/O routines can only read or overwriting existing
5931** blob content; they cannot change the size of a blob.
5932**
5933** This routine only works on a [BLOB handle] which has been created
5934** by a prior successful call to [sqlite3_blob_open()] and which has not
5935** been closed by [sqlite3_blob_close()].  Passing any other pointer in
5936** to this routine results in undefined and probably undesirable behavior.
5937*/
5938SQLITE_API int SQLITE_STDCALL sqlite3_blob_bytes(sqlite3_blob *);
5939
5940/*
5941** CAPI3REF: Read Data From A BLOB Incrementally
5942** METHOD: sqlite3_blob
5943**
5944** ^(This function is used to read data from an open [BLOB handle] into a
5945** caller-supplied buffer. N bytes of data are copied into buffer Z
5946** from the open BLOB, starting at offset iOffset.)^
5947**
5948** ^If offset iOffset is less than N bytes from the end of the BLOB,
5949** [SQLITE_ERROR] is returned and no data is read.  ^If N or iOffset is
5950** less than zero, [SQLITE_ERROR] is returned and no data is read.
5951** ^The size of the blob (and hence the maximum value of N+iOffset)
5952** can be determined using the [sqlite3_blob_bytes()] interface.
5953**
5954** ^An attempt to read from an expired [BLOB handle] fails with an
5955** error code of [SQLITE_ABORT].
5956**
5957** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
5958** Otherwise, an [error code] or an [extended error code] is returned.)^
5959**
5960** This routine only works on a [BLOB handle] which has been created
5961** by a prior successful call to [sqlite3_blob_open()] and which has not
5962** been closed by [sqlite3_blob_close()].  Passing any other pointer in
5963** to this routine results in undefined and probably undesirable behavior.
5964**
5965** See also: [sqlite3_blob_write()].
5966*/
5967SQLITE_API int SQLITE_STDCALL sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
5968
5969/*
5970** CAPI3REF: Write Data Into A BLOB Incrementally
5971** METHOD: sqlite3_blob
5972**
5973** ^(This function is used to write data into an open [BLOB handle] from a
5974** caller-supplied buffer. N bytes of data are copied from the buffer Z
5975** into the open BLOB, starting at offset iOffset.)^
5976**
5977** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
5978** Otherwise, an  [error code] or an [extended error code] is returned.)^
5979** ^Unless SQLITE_MISUSE is returned, this function sets the
5980** [database connection] error code and message accessible via
5981** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
5982**
5983** ^If the [BLOB handle] passed as the first argument was not opened for
5984** writing (the flags parameter to [sqlite3_blob_open()] was zero),
5985** this function returns [SQLITE_READONLY].
5986**
5987** This function may only modify the contents of the BLOB; it is
5988** not possible to increase the size of a BLOB using this API.
5989** ^If offset iOffset is less than N bytes from the end of the BLOB,
5990** [SQLITE_ERROR] is returned and no data is written. The size of the
5991** BLOB (and hence the maximum value of N+iOffset) can be determined
5992** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less
5993** than zero [SQLITE_ERROR] is returned and no data is written.
5994**
5995** ^An attempt to write to an expired [BLOB handle] fails with an
5996** error code of [SQLITE_ABORT].  ^Writes to the BLOB that occurred
5997** before the [BLOB handle] expired are not rolled back by the
5998** expiration of the handle, though of course those changes might
5999** have been overwritten by the statement that expired the BLOB handle
6000** or by other independent statements.
6001**
6002** This routine only works on a [BLOB handle] which has been created
6003** by a prior successful call to [sqlite3_blob_open()] and which has not
6004** been closed by [sqlite3_blob_close()].  Passing any other pointer in
6005** to this routine results in undefined and probably undesirable behavior.
6006**
6007** See also: [sqlite3_blob_read()].
6008*/
6009SQLITE_API int SQLITE_STDCALL sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
6010
6011/*
6012** CAPI3REF: Virtual File System Objects
6013**
6014** A virtual filesystem (VFS) is an [sqlite3_vfs] object
6015** that SQLite uses to interact
6016** with the underlying operating system.  Most SQLite builds come with a
6017** single default VFS that is appropriate for the host computer.
6018** New VFSes can be registered and existing VFSes can be unregistered.
6019** The following interfaces are provided.
6020**
6021** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
6022** ^Names are case sensitive.
6023** ^Names are zero-terminated UTF-8 strings.
6024** ^If there is no match, a NULL pointer is returned.
6025** ^If zVfsName is NULL then the default VFS is returned.
6026**
6027** ^New VFSes are registered with sqlite3_vfs_register().
6028** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
6029** ^The same VFS can be registered multiple times without injury.
6030** ^To make an existing VFS into the default VFS, register it again
6031** with the makeDflt flag set.  If two different VFSes with the
6032** same name are registered, the behavior is undefined.  If a
6033** VFS is registered with a name that is NULL or an empty string,
6034** then the behavior is undefined.
6035**
6036** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
6037** ^(If the default VFS is unregistered, another VFS is chosen as
6038** the default.  The choice for the new VFS is arbitrary.)^
6039*/
6040SQLITE_API sqlite3_vfs *SQLITE_STDCALL sqlite3_vfs_find(const char *zVfsName);
6041SQLITE_API int SQLITE_STDCALL sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
6042SQLITE_API int SQLITE_STDCALL sqlite3_vfs_unregister(sqlite3_vfs*);
6043
6044/*
6045** CAPI3REF: Mutexes
6046**
6047** The SQLite core uses these routines for thread
6048** synchronization. Though they are intended for internal
6049** use by SQLite, code that links against SQLite is
6050** permitted to use any of these routines.
6051**
6052** The SQLite source code contains multiple implementations
6053** of these mutex routines.  An appropriate implementation
6054** is selected automatically at compile-time.  The following
6055** implementations are available in the SQLite core:
6056**
6057** <ul>
6058** <li>   SQLITE_MUTEX_PTHREADS
6059** <li>   SQLITE_MUTEX_W32
6060** <li>   SQLITE_MUTEX_NOOP
6061** </ul>
6062**
6063** The SQLITE_MUTEX_NOOP implementation is a set of routines
6064** that does no real locking and is appropriate for use in
6065** a single-threaded application.  The SQLITE_MUTEX_PTHREADS and
6066** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
6067** and Windows.
6068**
6069** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
6070** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
6071** implementation is included with the library. In this case the
6072** application must supply a custom mutex implementation using the
6073** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
6074** before calling sqlite3_initialize() or any other public sqlite3_
6075** function that calls sqlite3_initialize().
6076**
6077** ^The sqlite3_mutex_alloc() routine allocates a new
6078** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc()
6079** routine returns NULL if it is unable to allocate the requested
6080** mutex.  The argument to sqlite3_mutex_alloc() must one of these
6081** integer constants:
6082**
6083** <ul>
6084** <li>  SQLITE_MUTEX_FAST
6085** <li>  SQLITE_MUTEX_RECURSIVE
6086** <li>  SQLITE_MUTEX_STATIC_MASTER
6087** <li>  SQLITE_MUTEX_STATIC_MEM
6088** <li>  SQLITE_MUTEX_STATIC_OPEN
6089** <li>  SQLITE_MUTEX_STATIC_PRNG
6090** <li>  SQLITE_MUTEX_STATIC_LRU
6091** <li>  SQLITE_MUTEX_STATIC_PMEM
6092** <li>  SQLITE_MUTEX_STATIC_APP1
6093** <li>  SQLITE_MUTEX_STATIC_APP2
6094** <li>  SQLITE_MUTEX_STATIC_APP3
6095** </ul>
6096**
6097** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
6098** cause sqlite3_mutex_alloc() to create
6099** a new mutex.  ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
6100** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
6101** The mutex implementation does not need to make a distinction
6102** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
6103** not want to.  SQLite will only request a recursive mutex in
6104** cases where it really needs one.  If a faster non-recursive mutex
6105** implementation is available on the host platform, the mutex subsystem
6106** might return such a mutex in response to SQLITE_MUTEX_FAST.
6107**
6108** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
6109** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
6110** a pointer to a static preexisting mutex.  ^Nine static mutexes are
6111** used by the current version of SQLite.  Future versions of SQLite
6112** may add additional static mutexes.  Static mutexes are for internal
6113** use by SQLite only.  Applications that use SQLite mutexes should
6114** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
6115** SQLITE_MUTEX_RECURSIVE.
6116**
6117** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
6118** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
6119** returns a different mutex on every call.  ^For the static
6120** mutex types, the same mutex is returned on every call that has
6121** the same type number.
6122**
6123** ^The sqlite3_mutex_free() routine deallocates a previously
6124** allocated dynamic mutex.  Attempting to deallocate a static
6125** mutex results in undefined behavior.
6126**
6127** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
6128** to enter a mutex.  ^If another thread is already within the mutex,
6129** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
6130** SQLITE_BUSY.  ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
6131** upon successful entry.  ^(Mutexes created using
6132** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
6133** In such cases, the
6134** mutex must be exited an equal number of times before another thread
6135** can enter.)^  If the same thread tries to enter any mutex other
6136** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined.
6137**
6138** ^(Some systems (for example, Windows 95) do not support the operation
6139** implemented by sqlite3_mutex_try().  On those systems, sqlite3_mutex_try()
6140** will always return SQLITE_BUSY. The SQLite core only ever uses
6141** sqlite3_mutex_try() as an optimization so this is acceptable
6142** behavior.)^
6143**
6144** ^The sqlite3_mutex_leave() routine exits a mutex that was
6145** previously entered by the same thread.   The behavior
6146** is undefined if the mutex is not currently entered by the
6147** calling thread or is not currently allocated.
6148**
6149** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
6150** sqlite3_mutex_leave() is a NULL pointer, then all three routines
6151** behave as no-ops.
6152**
6153** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
6154*/
6155SQLITE_API sqlite3_mutex *SQLITE_STDCALL sqlite3_mutex_alloc(int);
6156SQLITE_API void SQLITE_STDCALL sqlite3_mutex_free(sqlite3_mutex*);
6157SQLITE_API void SQLITE_STDCALL sqlite3_mutex_enter(sqlite3_mutex*);
6158SQLITE_API int SQLITE_STDCALL sqlite3_mutex_try(sqlite3_mutex*);
6159SQLITE_API void SQLITE_STDCALL sqlite3_mutex_leave(sqlite3_mutex*);
6160
6161/*
6162** CAPI3REF: Mutex Methods Object
6163**
6164** An instance of this structure defines the low-level routines
6165** used to allocate and use mutexes.
6166**
6167** Usually, the default mutex implementations provided by SQLite are
6168** sufficient, however the application has the option of substituting a custom
6169** implementation for specialized deployments or systems for which SQLite
6170** does not provide a suitable implementation. In this case, the application
6171** creates and populates an instance of this structure to pass
6172** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
6173** Additionally, an instance of this structure can be used as an
6174** output variable when querying the system for the current mutex
6175** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
6176**
6177** ^The xMutexInit method defined by this structure is invoked as
6178** part of system initialization by the sqlite3_initialize() function.
6179** ^The xMutexInit routine is called by SQLite exactly once for each
6180** effective call to [sqlite3_initialize()].
6181**
6182** ^The xMutexEnd method defined by this structure is invoked as
6183** part of system shutdown by the sqlite3_shutdown() function. The
6184** implementation of this method is expected to release all outstanding
6185** resources obtained by the mutex methods implementation, especially
6186** those obtained by the xMutexInit method.  ^The xMutexEnd()
6187** interface is invoked exactly once for each call to [sqlite3_shutdown()].
6188**
6189** ^(The remaining seven methods defined by this structure (xMutexAlloc,
6190** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
6191** xMutexNotheld) implement the following interfaces (respectively):
6192**
6193** <ul>
6194**   <li>  [sqlite3_mutex_alloc()] </li>
6195**   <li>  [sqlite3_mutex_free()] </li>
6196**   <li>  [sqlite3_mutex_enter()] </li>
6197**   <li>  [sqlite3_mutex_try()] </li>
6198**   <li>  [sqlite3_mutex_leave()] </li>
6199**   <li>  [sqlite3_mutex_held()] </li>
6200**   <li>  [sqlite3_mutex_notheld()] </li>
6201** </ul>)^
6202**
6203** The only difference is that the public sqlite3_XXX functions enumerated
6204** above silently ignore any invocations that pass a NULL pointer instead
6205** of a valid mutex handle. The implementations of the methods defined
6206** by this structure are not required to handle this case, the results
6207** of passing a NULL pointer instead of a valid mutex handle are undefined
6208** (i.e. it is acceptable to provide an implementation that segfaults if
6209** it is passed a NULL pointer).
6210**
6211** The xMutexInit() method must be threadsafe.  It must be harmless to
6212** invoke xMutexInit() multiple times within the same process and without
6213** intervening calls to xMutexEnd().  Second and subsequent calls to
6214** xMutexInit() must be no-ops.
6215**
6216** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
6217** and its associates).  Similarly, xMutexAlloc() must not use SQLite memory
6218** allocation for a static mutex.  ^However xMutexAlloc() may use SQLite
6219** memory allocation for a fast or recursive mutex.
6220**
6221** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
6222** called, but only if the prior call to xMutexInit returned SQLITE_OK.
6223** If xMutexInit fails in any way, it is expected to clean up after itself
6224** prior to returning.
6225*/
6226typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
6227struct sqlite3_mutex_methods {
6228  int (*xMutexInit)(void);
6229  int (*xMutexEnd)(void);
6230  sqlite3_mutex *(*xMutexAlloc)(int);
6231  void (*xMutexFree)(sqlite3_mutex *);
6232  void (*xMutexEnter)(sqlite3_mutex *);
6233  int (*xMutexTry)(sqlite3_mutex *);
6234  void (*xMutexLeave)(sqlite3_mutex *);
6235  int (*xMutexHeld)(sqlite3_mutex *);
6236  int (*xMutexNotheld)(sqlite3_mutex *);
6237};
6238
6239/*
6240** CAPI3REF: Mutex Verification Routines
6241**
6242** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
6243** are intended for use inside assert() statements.  The SQLite core
6244** never uses these routines except inside an assert() and applications
6245** are advised to follow the lead of the core.  The SQLite core only
6246** provides implementations for these routines when it is compiled
6247** with the SQLITE_DEBUG flag.  External mutex implementations
6248** are only required to provide these routines if SQLITE_DEBUG is
6249** defined and if NDEBUG is not defined.
6250**
6251** These routines should return true if the mutex in their argument
6252** is held or not held, respectively, by the calling thread.
6253**
6254** The implementation is not required to provide versions of these
6255** routines that actually work. If the implementation does not provide working
6256** versions of these routines, it should at least provide stubs that always
6257** return true so that one does not get spurious assertion failures.
6258**
6259** If the argument to sqlite3_mutex_held() is a NULL pointer then
6260** the routine should return 1.   This seems counter-intuitive since
6261** clearly the mutex cannot be held if it does not exist.  But
6262** the reason the mutex does not exist is because the build is not
6263** using mutexes.  And we do not want the assert() containing the
6264** call to sqlite3_mutex_held() to fail, so a non-zero return is
6265** the appropriate thing to do.  The sqlite3_mutex_notheld()
6266** interface should also return 1 when given a NULL pointer.
6267*/
6268#ifndef NDEBUG
6269SQLITE_API int SQLITE_STDCALL sqlite3_mutex_held(sqlite3_mutex*);
6270SQLITE_API int SQLITE_STDCALL sqlite3_mutex_notheld(sqlite3_mutex*);
6271#endif
6272
6273/*
6274** CAPI3REF: Mutex Types
6275**
6276** The [sqlite3_mutex_alloc()] interface takes a single argument
6277** which is one of these integer constants.
6278**
6279** The set of static mutexes may change from one SQLite release to the
6280** next.  Applications that override the built-in mutex logic must be
6281** prepared to accommodate additional static mutexes.
6282*/
6283#define SQLITE_MUTEX_FAST             0
6284#define SQLITE_MUTEX_RECURSIVE        1
6285#define SQLITE_MUTEX_STATIC_MASTER    2
6286#define SQLITE_MUTEX_STATIC_MEM       3  /* sqlite3_malloc() */
6287#define SQLITE_MUTEX_STATIC_MEM2      4  /* NOT USED */
6288#define SQLITE_MUTEX_STATIC_OPEN      4  /* sqlite3BtreeOpen() */
6289#define SQLITE_MUTEX_STATIC_PRNG      5  /* sqlite3_random() */
6290#define SQLITE_MUTEX_STATIC_LRU       6  /* lru page list */
6291#define SQLITE_MUTEX_STATIC_LRU2      7  /* NOT USED */
6292#define SQLITE_MUTEX_STATIC_PMEM      7  /* sqlite3PageMalloc() */
6293#define SQLITE_MUTEX_STATIC_APP1      8  /* For use by application */
6294#define SQLITE_MUTEX_STATIC_APP2      9  /* For use by application */
6295#define SQLITE_MUTEX_STATIC_APP3     10  /* For use by application */
6296#define SQLITE_MUTEX_STATIC_VFS1     11  /* For use by built-in VFS */
6297#define SQLITE_MUTEX_STATIC_VFS2     12  /* For use by extension VFS */
6298#define SQLITE_MUTEX_STATIC_VFS3     13  /* For use by application VFS */
6299
6300/*
6301** CAPI3REF: Retrieve the mutex for a database connection
6302** METHOD: sqlite3
6303**
6304** ^This interface returns a pointer the [sqlite3_mutex] object that
6305** serializes access to the [database connection] given in the argument
6306** when the [threading mode] is Serialized.
6307** ^If the [threading mode] is Single-thread or Multi-thread then this
6308** routine returns a NULL pointer.
6309*/
6310SQLITE_API sqlite3_mutex *SQLITE_STDCALL sqlite3_db_mutex(sqlite3*);
6311
6312/*
6313** CAPI3REF: Low-Level Control Of Database Files
6314** METHOD: sqlite3
6315**
6316** ^The [sqlite3_file_control()] interface makes a direct call to the
6317** xFileControl method for the [sqlite3_io_methods] object associated
6318** with a particular database identified by the second argument. ^The
6319** name of the database is "main" for the main database or "temp" for the
6320** TEMP database, or the name that appears after the AS keyword for
6321** databases that are added using the [ATTACH] SQL command.
6322** ^A NULL pointer can be used in place of "main" to refer to the
6323** main database file.
6324** ^The third and fourth parameters to this routine
6325** are passed directly through to the second and third parameters of
6326** the xFileControl method.  ^The return value of the xFileControl
6327** method becomes the return value of this routine.
6328**
6329** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes
6330** a pointer to the underlying [sqlite3_file] object to be written into
6331** the space pointed to by the 4th parameter.  ^The SQLITE_FCNTL_FILE_POINTER
6332** case is a short-circuit path which does not actually invoke the
6333** underlying sqlite3_io_methods.xFileControl method.
6334**
6335** ^If the second parameter (zDbName) does not match the name of any
6336** open database file, then SQLITE_ERROR is returned.  ^This error
6337** code is not remembered and will not be recalled by [sqlite3_errcode()]
6338** or [sqlite3_errmsg()].  The underlying xFileControl method might
6339** also return SQLITE_ERROR.  There is no way to distinguish between
6340** an incorrect zDbName and an SQLITE_ERROR return from the underlying
6341** xFileControl method.
6342**
6343** See also: [SQLITE_FCNTL_LOCKSTATE]
6344*/
6345SQLITE_API int SQLITE_STDCALL sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
6346
6347/*
6348** CAPI3REF: Testing Interface
6349**
6350** ^The sqlite3_test_control() interface is used to read out internal
6351** state of SQLite and to inject faults into SQLite for testing
6352** purposes.  ^The first parameter is an operation code that determines
6353** the number, meaning, and operation of all subsequent parameters.
6354**
6355** This interface is not for use by applications.  It exists solely
6356** for verifying the correct operation of the SQLite library.  Depending
6357** on how the SQLite library is compiled, this interface might not exist.
6358**
6359** The details of the operation codes, their meanings, the parameters
6360** they take, and what they do are all subject to change without notice.
6361** Unlike most of the SQLite API, this function is not guaranteed to
6362** operate consistently from one release to the next.
6363*/
6364SQLITE_API int SQLITE_CDECL sqlite3_test_control(int op, ...);
6365
6366/*
6367** CAPI3REF: Testing Interface Operation Codes
6368**
6369** These constants are the valid operation code parameters used
6370** as the first argument to [sqlite3_test_control()].
6371**
6372** These parameters and their meanings are subject to change
6373** without notice.  These values are for testing purposes only.
6374** Applications should not use any of these parameters or the
6375** [sqlite3_test_control()] interface.
6376*/
6377#define SQLITE_TESTCTRL_FIRST                    5
6378#define SQLITE_TESTCTRL_PRNG_SAVE                5
6379#define SQLITE_TESTCTRL_PRNG_RESTORE             6
6380#define SQLITE_TESTCTRL_PRNG_RESET               7
6381#define SQLITE_TESTCTRL_BITVEC_TEST              8
6382#define SQLITE_TESTCTRL_FAULT_INSTALL            9
6383#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS     10
6384#define SQLITE_TESTCTRL_PENDING_BYTE            11
6385#define SQLITE_TESTCTRL_ASSERT                  12
6386#define SQLITE_TESTCTRL_ALWAYS                  13
6387#define SQLITE_TESTCTRL_RESERVE                 14
6388#define SQLITE_TESTCTRL_OPTIMIZATIONS           15
6389#define SQLITE_TESTCTRL_ISKEYWORD               16
6390#define SQLITE_TESTCTRL_SCRATCHMALLOC           17
6391#define SQLITE_TESTCTRL_LOCALTIME_FAULT         18
6392#define SQLITE_TESTCTRL_EXPLAIN_STMT            19  /* NOT USED */
6393#define SQLITE_TESTCTRL_NEVER_CORRUPT           20
6394#define SQLITE_TESTCTRL_VDBE_COVERAGE           21
6395#define SQLITE_TESTCTRL_BYTEORDER               22
6396#define SQLITE_TESTCTRL_ISINIT                  23
6397#define SQLITE_TESTCTRL_SORTER_MMAP             24
6398#define SQLITE_TESTCTRL_IMPOSTER                25
6399#define SQLITE_TESTCTRL_LAST                    25
6400
6401/*
6402** CAPI3REF: SQLite Runtime Status
6403**
6404** ^These interfaces are used to retrieve runtime status information
6405** about the performance of SQLite, and optionally to reset various
6406** highwater marks.  ^The first argument is an integer code for
6407** the specific parameter to measure.  ^(Recognized integer codes
6408** are of the form [status parameters | SQLITE_STATUS_...].)^
6409** ^The current value of the parameter is returned into *pCurrent.
6410** ^The highest recorded value is returned in *pHighwater.  ^If the
6411** resetFlag is true, then the highest record value is reset after
6412** *pHighwater is written.  ^(Some parameters do not record the highest
6413** value.  For those parameters
6414** nothing is written into *pHighwater and the resetFlag is ignored.)^
6415** ^(Other parameters record only the highwater mark and not the current
6416** value.  For these latter parameters nothing is written into *pCurrent.)^
6417**
6418** ^The sqlite3_status() and sqlite3_status64() routines return
6419** SQLITE_OK on success and a non-zero [error code] on failure.
6420**
6421** If either the current value or the highwater mark is too large to
6422** be represented by a 32-bit integer, then the values returned by
6423** sqlite3_status() are undefined.
6424**
6425** See also: [sqlite3_db_status()]
6426*/
6427SQLITE_API int SQLITE_STDCALL sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
6428SQLITE_API int SQLITE_STDCALL sqlite3_status64(
6429  int op,
6430  sqlite3_int64 *pCurrent,
6431  sqlite3_int64 *pHighwater,
6432  int resetFlag
6433);
6434
6435
6436/*
6437** CAPI3REF: Status Parameters
6438** KEYWORDS: {status parameters}
6439**
6440** These integer constants designate various run-time status parameters
6441** that can be returned by [sqlite3_status()].
6442**
6443** <dl>
6444** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
6445** <dd>This parameter is the current amount of memory checked out
6446** using [sqlite3_malloc()], either directly or indirectly.  The
6447** figure includes calls made to [sqlite3_malloc()] by the application
6448** and internal memory usage by the SQLite library.  Scratch memory
6449** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache
6450** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
6451** this parameter.  The amount returned is the sum of the allocation
6452** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
6453**
6454** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
6455** <dd>This parameter records the largest memory allocation request
6456** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
6457** internal equivalents).  Only the value returned in the
6458** *pHighwater parameter to [sqlite3_status()] is of interest.
6459** The value written into the *pCurrent parameter is undefined.</dd>)^
6460**
6461** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
6462** <dd>This parameter records the number of separate memory allocations
6463** currently checked out.</dd>)^
6464**
6465** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
6466** <dd>This parameter returns the number of pages used out of the
6467** [pagecache memory allocator] that was configured using
6468** [SQLITE_CONFIG_PAGECACHE].  The
6469** value returned is in pages, not in bytes.</dd>)^
6470**
6471** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]]
6472** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
6473** <dd>This parameter returns the number of bytes of page cache
6474** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
6475** buffer and where forced to overflow to [sqlite3_malloc()].  The
6476** returned value includes allocations that overflowed because they
6477** where too large (they were larger than the "sz" parameter to
6478** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
6479** no space was left in the page cache.</dd>)^
6480**
6481** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
6482** <dd>This parameter records the largest memory allocation request
6483** handed to [pagecache memory allocator].  Only the value returned in the
6484** *pHighwater parameter to [sqlite3_status()] is of interest.
6485** The value written into the *pCurrent parameter is undefined.</dd>)^
6486**
6487** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt>
6488** <dd>This parameter returns the number of allocations used out of the
6489** [scratch memory allocator] configured using
6490** [SQLITE_CONFIG_SCRATCH].  The value returned is in allocations, not
6491** in bytes.  Since a single thread may only have one scratch allocation
6492** outstanding at time, this parameter also reports the number of threads
6493** using scratch memory at the same time.</dd>)^
6494**
6495** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
6496** <dd>This parameter returns the number of bytes of scratch memory
6497** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH]
6498** buffer and where forced to overflow to [sqlite3_malloc()].  The values
6499** returned include overflows because the requested allocation was too
6500** larger (that is, because the requested allocation was larger than the
6501** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer
6502** slots were available.
6503** </dd>)^
6504**
6505** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
6506** <dd>This parameter records the largest memory allocation request
6507** handed to [scratch memory allocator].  Only the value returned in the
6508** *pHighwater parameter to [sqlite3_status()] is of interest.
6509** The value written into the *pCurrent parameter is undefined.</dd>)^
6510**
6511** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
6512** <dd>This parameter records the deepest parser stack.  It is only
6513** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
6514** </dl>
6515**
6516** New status parameters may be added from time to time.
6517*/
6518#define SQLITE_STATUS_MEMORY_USED          0
6519#define SQLITE_STATUS_PAGECACHE_USED       1
6520#define SQLITE_STATUS_PAGECACHE_OVERFLOW   2
6521#define SQLITE_STATUS_SCRATCH_USED         3
6522#define SQLITE_STATUS_SCRATCH_OVERFLOW     4
6523#define SQLITE_STATUS_MALLOC_SIZE          5
6524#define SQLITE_STATUS_PARSER_STACK         6
6525#define SQLITE_STATUS_PAGECACHE_SIZE       7
6526#define SQLITE_STATUS_SCRATCH_SIZE         8
6527#define SQLITE_STATUS_MALLOC_COUNT         9
6528
6529/*
6530** CAPI3REF: Database Connection Status
6531** METHOD: sqlite3
6532**
6533** ^This interface is used to retrieve runtime status information
6534** about a single [database connection].  ^The first argument is the
6535** database connection object to be interrogated.  ^The second argument
6536** is an integer constant, taken from the set of
6537** [SQLITE_DBSTATUS options], that
6538** determines the parameter to interrogate.  The set of
6539** [SQLITE_DBSTATUS options] is likely
6540** to grow in future releases of SQLite.
6541**
6542** ^The current value of the requested parameter is written into *pCur
6543** and the highest instantaneous value is written into *pHiwtr.  ^If
6544** the resetFlg is true, then the highest instantaneous value is
6545** reset back down to the current value.
6546**
6547** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
6548** non-zero [error code] on failure.
6549**
6550** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
6551*/
6552SQLITE_API int SQLITE_STDCALL sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
6553
6554/*
6555** CAPI3REF: Status Parameters for database connections
6556** KEYWORDS: {SQLITE_DBSTATUS options}
6557**
6558** These constants are the available integer "verbs" that can be passed as
6559** the second argument to the [sqlite3_db_status()] interface.
6560**
6561** New verbs may be added in future releases of SQLite. Existing verbs
6562** might be discontinued. Applications should check the return code from
6563** [sqlite3_db_status()] to make sure that the call worked.
6564** The [sqlite3_db_status()] interface will return a non-zero error code
6565** if a discontinued or unsupported verb is invoked.
6566**
6567** <dl>
6568** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
6569** <dd>This parameter returns the number of lookaside memory slots currently
6570** checked out.</dd>)^
6571**
6572** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
6573** <dd>This parameter returns the number malloc attempts that were
6574** satisfied using lookaside memory. Only the high-water value is meaningful;
6575** the current value is always zero.)^
6576**
6577** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]]
6578** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
6579** <dd>This parameter returns the number malloc attempts that might have
6580** been satisfied using lookaside memory but failed due to the amount of
6581** memory requested being larger than the lookaside slot size.
6582** Only the high-water value is meaningful;
6583** the current value is always zero.)^
6584**
6585** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]]
6586** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
6587** <dd>This parameter returns the number malloc attempts that might have
6588** been satisfied using lookaside memory but failed due to all lookaside
6589** memory already being in use.
6590** Only the high-water value is meaningful;
6591** the current value is always zero.)^
6592**
6593** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
6594** <dd>This parameter returns the approximate number of bytes of heap
6595** memory used by all pager caches associated with the database connection.)^
6596** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
6597**
6598** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
6599** <dd>This parameter returns the approximate number of bytes of heap
6600** memory used to store the schema for all databases associated
6601** with the connection - main, temp, and any [ATTACH]-ed databases.)^
6602** ^The full amount of memory used by the schemas is reported, even if the
6603** schema memory is shared with other database connections due to
6604** [shared cache mode] being enabled.
6605** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
6606**
6607** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
6608** <dd>This parameter returns the approximate number of bytes of heap
6609** and lookaside memory used by all prepared statements associated with
6610** the database connection.)^
6611** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
6612** </dd>
6613**
6614** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt>
6615** <dd>This parameter returns the number of pager cache hits that have
6616** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT
6617** is always 0.
6618** </dd>
6619**
6620** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt>
6621** <dd>This parameter returns the number of pager cache misses that have
6622** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS
6623** is always 0.
6624** </dd>
6625**
6626** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt>
6627** <dd>This parameter returns the number of dirty cache entries that have
6628** been written to disk. Specifically, the number of pages written to the
6629** wal file in wal mode databases, or the number of pages written to the
6630** database file in rollback mode databases. Any pages written as part of
6631** transaction rollback or database recovery operations are not included.
6632** If an IO or other error occurs while writing a page to disk, the effect
6633** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The
6634** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0.
6635** </dd>
6636**
6637** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt>
6638** <dd>This parameter returns zero for the current value if and only if
6639** all foreign key constraints (deferred or immediate) have been
6640** resolved.)^  ^The highwater mark is always 0.
6641** </dd>
6642** </dl>
6643*/
6644#define SQLITE_DBSTATUS_LOOKASIDE_USED       0
6645#define SQLITE_DBSTATUS_CACHE_USED           1
6646#define SQLITE_DBSTATUS_SCHEMA_USED          2
6647#define SQLITE_DBSTATUS_STMT_USED            3
6648#define SQLITE_DBSTATUS_LOOKASIDE_HIT        4
6649#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE  5
6650#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL  6
6651#define SQLITE_DBSTATUS_CACHE_HIT            7
6652#define SQLITE_DBSTATUS_CACHE_MISS           8
6653#define SQLITE_DBSTATUS_CACHE_WRITE          9
6654#define SQLITE_DBSTATUS_DEFERRED_FKS        10
6655#define SQLITE_DBSTATUS_MAX                 10   /* Largest defined DBSTATUS */
6656
6657
6658/*
6659** CAPI3REF: Prepared Statement Status
6660** METHOD: sqlite3_stmt
6661**
6662** ^(Each prepared statement maintains various
6663** [SQLITE_STMTSTATUS counters] that measure the number
6664** of times it has performed specific operations.)^  These counters can
6665** be used to monitor the performance characteristics of the prepared
6666** statements.  For example, if the number of table steps greatly exceeds
6667** the number of table searches or result rows, that would tend to indicate
6668** that the prepared statement is using a full table scan rather than
6669** an index.
6670**
6671** ^(This interface is used to retrieve and reset counter values from
6672** a [prepared statement].  The first argument is the prepared statement
6673** object to be interrogated.  The second argument
6674** is an integer code for a specific [SQLITE_STMTSTATUS counter]
6675** to be interrogated.)^
6676** ^The current value of the requested counter is returned.
6677** ^If the resetFlg is true, then the counter is reset to zero after this
6678** interface call returns.
6679**
6680** See also: [sqlite3_status()] and [sqlite3_db_status()].
6681*/
6682SQLITE_API int SQLITE_STDCALL sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
6683
6684/*
6685** CAPI3REF: Status Parameters for prepared statements
6686** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters}
6687**
6688** These preprocessor macros define integer codes that name counter
6689** values associated with the [sqlite3_stmt_status()] interface.
6690** The meanings of the various counters are as follows:
6691**
6692** <dl>
6693** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
6694** <dd>^This is the number of times that SQLite has stepped forward in
6695** a table as part of a full table scan.  Large numbers for this counter
6696** may indicate opportunities for performance improvement through
6697** careful use of indices.</dd>
6698**
6699** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt>
6700** <dd>^This is the number of sort operations that have occurred.
6701** A non-zero value in this counter may indicate an opportunity to
6702** improvement performance through careful use of indices.</dd>
6703**
6704** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
6705** <dd>^This is the number of rows inserted into transient indices that
6706** were created automatically in order to help joins run faster.
6707** A non-zero value in this counter may indicate an opportunity to
6708** improvement performance by adding permanent indices that do not
6709** need to be reinitialized each time the statement is run.</dd>
6710**
6711** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt>
6712** <dd>^This is the number of virtual machine operations executed
6713** by the prepared statement if that number is less than or equal
6714** to 2147483647.  The number of virtual machine operations can be
6715** used as a proxy for the total work done by the prepared statement.
6716** If the number of virtual machine operations exceeds 2147483647
6717** then the value returned by this statement status code is undefined.
6718** </dd>
6719** </dl>
6720*/
6721#define SQLITE_STMTSTATUS_FULLSCAN_STEP     1
6722#define SQLITE_STMTSTATUS_SORT              2
6723#define SQLITE_STMTSTATUS_AUTOINDEX         3
6724#define SQLITE_STMTSTATUS_VM_STEP           4
6725
6726/*
6727** CAPI3REF: Custom Page Cache Object
6728**
6729** The sqlite3_pcache type is opaque.  It is implemented by
6730** the pluggable module.  The SQLite core has no knowledge of
6731** its size or internal structure and never deals with the
6732** sqlite3_pcache object except by holding and passing pointers
6733** to the object.
6734**
6735** See [sqlite3_pcache_methods2] for additional information.
6736*/
6737typedef struct sqlite3_pcache sqlite3_pcache;
6738
6739/*
6740** CAPI3REF: Custom Page Cache Object
6741**
6742** The sqlite3_pcache_page object represents a single page in the
6743** page cache.  The page cache will allocate instances of this
6744** object.  Various methods of the page cache use pointers to instances
6745** of this object as parameters or as their return value.
6746**
6747** See [sqlite3_pcache_methods2] for additional information.
6748*/
6749typedef struct sqlite3_pcache_page sqlite3_pcache_page;
6750struct sqlite3_pcache_page {
6751  void *pBuf;        /* The content of the page */
6752  void *pExtra;      /* Extra information associated with the page */
6753};
6754
6755/*
6756** CAPI3REF: Application Defined Page Cache.
6757** KEYWORDS: {page cache}
6758**
6759** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can
6760** register an alternative page cache implementation by passing in an
6761** instance of the sqlite3_pcache_methods2 structure.)^
6762** In many applications, most of the heap memory allocated by
6763** SQLite is used for the page cache.
6764** By implementing a
6765** custom page cache using this API, an application can better control
6766** the amount of memory consumed by SQLite, the way in which
6767** that memory is allocated and released, and the policies used to
6768** determine exactly which parts of a database file are cached and for
6769** how long.
6770**
6771** The alternative page cache mechanism is an
6772** extreme measure that is only needed by the most demanding applications.
6773** The built-in page cache is recommended for most uses.
6774**
6775** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an
6776** internal buffer by SQLite within the call to [sqlite3_config].  Hence
6777** the application may discard the parameter after the call to
6778** [sqlite3_config()] returns.)^
6779**
6780** [[the xInit() page cache method]]
6781** ^(The xInit() method is called once for each effective
6782** call to [sqlite3_initialize()])^
6783** (usually only once during the lifetime of the process). ^(The xInit()
6784** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^
6785** The intent of the xInit() method is to set up global data structures
6786** required by the custom page cache implementation.
6787** ^(If the xInit() method is NULL, then the
6788** built-in default page cache is used instead of the application defined
6789** page cache.)^
6790**
6791** [[the xShutdown() page cache method]]
6792** ^The xShutdown() method is called by [sqlite3_shutdown()].
6793** It can be used to clean up
6794** any outstanding resources before process shutdown, if required.
6795** ^The xShutdown() method may be NULL.
6796**
6797** ^SQLite automatically serializes calls to the xInit method,
6798** so the xInit method need not be threadsafe.  ^The
6799** xShutdown method is only called from [sqlite3_shutdown()] so it does
6800** not need to be threadsafe either.  All other methods must be threadsafe
6801** in multithreaded applications.
6802**
6803** ^SQLite will never invoke xInit() more than once without an intervening
6804** call to xShutdown().
6805**
6806** [[the xCreate() page cache methods]]
6807** ^SQLite invokes the xCreate() method to construct a new cache instance.
6808** SQLite will typically create one cache instance for each open database file,
6809** though this is not guaranteed. ^The
6810** first parameter, szPage, is the size in bytes of the pages that must
6811** be allocated by the cache.  ^szPage will always a power of two.  ^The
6812** second parameter szExtra is a number of bytes of extra storage
6813** associated with each page cache entry.  ^The szExtra parameter will
6814** a number less than 250.  SQLite will use the
6815** extra szExtra bytes on each page to store metadata about the underlying
6816** database page on disk.  The value passed into szExtra depends
6817** on the SQLite version, the target platform, and how SQLite was compiled.
6818** ^The third argument to xCreate(), bPurgeable, is true if the cache being
6819** created will be used to cache database pages of a file stored on disk, or
6820** false if it is used for an in-memory database. The cache implementation
6821** does not have to do anything special based with the value of bPurgeable;
6822** it is purely advisory.  ^On a cache where bPurgeable is false, SQLite will
6823** never invoke xUnpin() except to deliberately delete a page.
6824** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
6825** false will always have the "discard" flag set to true.
6826** ^Hence, a cache created with bPurgeable false will
6827** never contain any unpinned pages.
6828**
6829** [[the xCachesize() page cache method]]
6830** ^(The xCachesize() method may be called at any time by SQLite to set the
6831** suggested maximum cache-size (number of pages stored by) the cache
6832** instance passed as the first argument. This is the value configured using
6833** the SQLite "[PRAGMA cache_size]" command.)^  As with the bPurgeable
6834** parameter, the implementation is not required to do anything with this
6835** value; it is advisory only.
6836**
6837** [[the xPagecount() page cache methods]]
6838** The xPagecount() method must return the number of pages currently
6839** stored in the cache, both pinned and unpinned.
6840**
6841** [[the xFetch() page cache methods]]
6842** The xFetch() method locates a page in the cache and returns a pointer to
6843** an sqlite3_pcache_page object associated with that page, or a NULL pointer.
6844** The pBuf element of the returned sqlite3_pcache_page object will be a
6845** pointer to a buffer of szPage bytes used to store the content of a
6846** single database page.  The pExtra element of sqlite3_pcache_page will be
6847** a pointer to the szExtra bytes of extra storage that SQLite has requested
6848** for each entry in the page cache.
6849**
6850** The page to be fetched is determined by the key. ^The minimum key value
6851** is 1.  After it has been retrieved using xFetch, the page is considered
6852** to be "pinned".
6853**
6854** If the requested page is already in the page cache, then the page cache
6855** implementation must return a pointer to the page buffer with its content
6856** intact.  If the requested page is not already in the cache, then the
6857** cache implementation should use the value of the createFlag
6858** parameter to help it determined what action to take:
6859**
6860** <table border=1 width=85% align=center>
6861** <tr><th> createFlag <th> Behavior when page is not already in cache
6862** <tr><td> 0 <td> Do not allocate a new page.  Return NULL.
6863** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
6864**                 Otherwise return NULL.
6865** <tr><td> 2 <td> Make every effort to allocate a new page.  Only return
6866**                 NULL if allocating a new page is effectively impossible.
6867** </table>
6868**
6869** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1.  SQLite
6870** will only use a createFlag of 2 after a prior call with a createFlag of 1
6871** failed.)^  In between the to xFetch() calls, SQLite may
6872** attempt to unpin one or more cache pages by spilling the content of
6873** pinned pages to disk and synching the operating system disk cache.
6874**
6875** [[the xUnpin() page cache method]]
6876** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
6877** as its second argument.  If the third parameter, discard, is non-zero,
6878** then the page must be evicted from the cache.
6879** ^If the discard parameter is
6880** zero, then the page may be discarded or retained at the discretion of
6881** page cache implementation. ^The page cache implementation
6882** may choose to evict unpinned pages at any time.
6883**
6884** The cache must not perform any reference counting. A single
6885** call to xUnpin() unpins the page regardless of the number of prior calls
6886** to xFetch().
6887**
6888** [[the xRekey() page cache methods]]
6889** The xRekey() method is used to change the key value associated with the
6890** page passed as the second argument. If the cache
6891** previously contains an entry associated with newKey, it must be
6892** discarded. ^Any prior cache entry associated with newKey is guaranteed not
6893** to be pinned.
6894**
6895** When SQLite calls the xTruncate() method, the cache must discard all
6896** existing cache entries with page numbers (keys) greater than or equal
6897** to the value of the iLimit parameter passed to xTruncate(). If any
6898** of these pages are pinned, they are implicitly unpinned, meaning that
6899** they can be safely discarded.
6900**
6901** [[the xDestroy() page cache method]]
6902** ^The xDestroy() method is used to delete a cache allocated by xCreate().
6903** All resources associated with the specified cache should be freed. ^After
6904** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
6905** handle invalid, and will not use it with any other sqlite3_pcache_methods2
6906** functions.
6907**
6908** [[the xShrink() page cache method]]
6909** ^SQLite invokes the xShrink() method when it wants the page cache to
6910** free up as much of heap memory as possible.  The page cache implementation
6911** is not obligated to free any memory, but well-behaved implementations should
6912** do their best.
6913*/
6914typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
6915struct sqlite3_pcache_methods2 {
6916  int iVersion;
6917  void *pArg;
6918  int (*xInit)(void*);
6919  void (*xShutdown)(void*);
6920  sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
6921  void (*xCachesize)(sqlite3_pcache*, int nCachesize);
6922  int (*xPagecount)(sqlite3_pcache*);
6923  sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
6924  void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
6925  void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*,
6926      unsigned oldKey, unsigned newKey);
6927  void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
6928  void (*xDestroy)(sqlite3_pcache*);
6929  void (*xShrink)(sqlite3_pcache*);
6930};
6931
6932/*
6933** This is the obsolete pcache_methods object that has now been replaced
6934** by sqlite3_pcache_methods2.  This object is not used by SQLite.  It is
6935** retained in the header file for backwards compatibility only.
6936*/
6937typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
6938struct sqlite3_pcache_methods {
6939  void *pArg;
6940  int (*xInit)(void*);
6941  void (*xShutdown)(void*);
6942  sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
6943  void (*xCachesize)(sqlite3_pcache*, int nCachesize);
6944  int (*xPagecount)(sqlite3_pcache*);
6945  void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
6946  void (*xUnpin)(sqlite3_pcache*, void*, int discard);
6947  void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
6948  void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
6949  void (*xDestroy)(sqlite3_pcache*);
6950};
6951
6952
6953/*
6954** CAPI3REF: Online Backup Object
6955**
6956** The sqlite3_backup object records state information about an ongoing
6957** online backup operation.  ^The sqlite3_backup object is created by
6958** a call to [sqlite3_backup_init()] and is destroyed by a call to
6959** [sqlite3_backup_finish()].
6960**
6961** See Also: [Using the SQLite Online Backup API]
6962*/
6963typedef struct sqlite3_backup sqlite3_backup;
6964
6965/*
6966** CAPI3REF: Online Backup API.
6967**
6968** The backup API copies the content of one database into another.
6969** It is useful either for creating backups of databases or
6970** for copying in-memory databases to or from persistent files.
6971**
6972** See Also: [Using the SQLite Online Backup API]
6973**
6974** ^SQLite holds a write transaction open on the destination database file
6975** for the duration of the backup operation.
6976** ^The source database is read-locked only while it is being read;
6977** it is not locked continuously for the entire backup operation.
6978** ^Thus, the backup may be performed on a live source database without
6979** preventing other database connections from
6980** reading or writing to the source database while the backup is underway.
6981**
6982** ^(To perform a backup operation:
6983**   <ol>
6984**     <li><b>sqlite3_backup_init()</b> is called once to initialize the
6985**         backup,
6986**     <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
6987**         the data between the two databases, and finally
6988**     <li><b>sqlite3_backup_finish()</b> is called to release all resources
6989**         associated with the backup operation.
6990**   </ol>)^
6991** There should be exactly one call to sqlite3_backup_finish() for each
6992** successful call to sqlite3_backup_init().
6993**
6994** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
6995**
6996** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
6997** [database connection] associated with the destination database
6998** and the database name, respectively.
6999** ^The database name is "main" for the main database, "temp" for the
7000** temporary database, or the name specified after the AS keyword in
7001** an [ATTACH] statement for an attached database.
7002** ^The S and M arguments passed to
7003** sqlite3_backup_init(D,N,S,M) identify the [database connection]
7004** and database name of the source database, respectively.
7005** ^The source and destination [database connections] (parameters S and D)
7006** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
7007** an error.
7008**
7009** ^A call to sqlite3_backup_init() will fail, returning SQLITE_ERROR, if
7010** there is already a read or read-write transaction open on the
7011** destination database.
7012**
7013** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
7014** returned and an error code and error message are stored in the
7015** destination [database connection] D.
7016** ^The error code and message for the failed call to sqlite3_backup_init()
7017** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
7018** [sqlite3_errmsg16()] functions.
7019** ^A successful call to sqlite3_backup_init() returns a pointer to an
7020** [sqlite3_backup] object.
7021** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
7022** sqlite3_backup_finish() functions to perform the specified backup
7023** operation.
7024**
7025** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
7026**
7027** ^Function sqlite3_backup_step(B,N) will copy up to N pages between
7028** the source and destination databases specified by [sqlite3_backup] object B.
7029** ^If N is negative, all remaining source pages are copied.
7030** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
7031** are still more pages to be copied, then the function returns [SQLITE_OK].
7032** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
7033** from source to destination, then it returns [SQLITE_DONE].
7034** ^If an error occurs while running sqlite3_backup_step(B,N),
7035** then an [error code] is returned. ^As well as [SQLITE_OK] and
7036** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
7037** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
7038** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
7039**
7040** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
7041** <ol>
7042** <li> the destination database was opened read-only, or
7043** <li> the destination database is using write-ahead-log journaling
7044** and the destination and source page sizes differ, or
7045** <li> the destination database is an in-memory database and the
7046** destination and source page sizes differ.
7047** </ol>)^
7048**
7049** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
7050** the [sqlite3_busy_handler | busy-handler function]
7051** is invoked (if one is specified). ^If the
7052** busy-handler returns non-zero before the lock is available, then
7053** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
7054** sqlite3_backup_step() can be retried later. ^If the source
7055** [database connection]
7056** is being used to write to the source database when sqlite3_backup_step()
7057** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
7058** case the call to sqlite3_backup_step() can be retried later on. ^(If
7059** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
7060** [SQLITE_READONLY] is returned, then
7061** there is no point in retrying the call to sqlite3_backup_step(). These
7062** errors are considered fatal.)^  The application must accept
7063** that the backup operation has failed and pass the backup operation handle
7064** to the sqlite3_backup_finish() to release associated resources.
7065**
7066** ^The first call to sqlite3_backup_step() obtains an exclusive lock
7067** on the destination file. ^The exclusive lock is not released until either
7068** sqlite3_backup_finish() is called or the backup operation is complete
7069** and sqlite3_backup_step() returns [SQLITE_DONE].  ^Every call to
7070** sqlite3_backup_step() obtains a [shared lock] on the source database that
7071** lasts for the duration of the sqlite3_backup_step() call.
7072** ^Because the source database is not locked between calls to
7073** sqlite3_backup_step(), the source database may be modified mid-way
7074** through the backup process.  ^If the source database is modified by an
7075** external process or via a database connection other than the one being
7076** used by the backup operation, then the backup will be automatically
7077** restarted by the next call to sqlite3_backup_step(). ^If the source
7078** database is modified by the using the same database connection as is used
7079** by the backup operation, then the backup database is automatically
7080** updated at the same time.
7081**
7082** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
7083**
7084** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the
7085** application wishes to abandon the backup operation, the application
7086** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
7087** ^The sqlite3_backup_finish() interfaces releases all
7088** resources associated with the [sqlite3_backup] object.
7089** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
7090** active write-transaction on the destination database is rolled back.
7091** The [sqlite3_backup] object is invalid
7092** and may not be used following a call to sqlite3_backup_finish().
7093**
7094** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
7095** sqlite3_backup_step() errors occurred, regardless or whether or not
7096** sqlite3_backup_step() completed.
7097** ^If an out-of-memory condition or IO error occurred during any prior
7098** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
7099** sqlite3_backup_finish() returns the corresponding [error code].
7100**
7101** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
7102** is not a permanent error and does not affect the return value of
7103** sqlite3_backup_finish().
7104**
7105** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]]
7106** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
7107**
7108** ^The sqlite3_backup_remaining() routine returns the number of pages still
7109** to be backed up at the conclusion of the most recent sqlite3_backup_step().
7110** ^The sqlite3_backup_pagecount() routine returns the total number of pages
7111** in the source database at the conclusion of the most recent
7112** sqlite3_backup_step().
7113** ^(The values returned by these functions are only updated by
7114** sqlite3_backup_step(). If the source database is modified in a way that
7115** changes the size of the source database or the number of pages remaining,
7116** those changes are not reflected in the output of sqlite3_backup_pagecount()
7117** and sqlite3_backup_remaining() until after the next
7118** sqlite3_backup_step().)^
7119**
7120** <b>Concurrent Usage of Database Handles</b>
7121**
7122** ^The source [database connection] may be used by the application for other
7123** purposes while a backup operation is underway or being initialized.
7124** ^If SQLite is compiled and configured to support threadsafe database
7125** connections, then the source database connection may be used concurrently
7126** from within other threads.
7127**
7128** However, the application must guarantee that the destination
7129** [database connection] is not passed to any other API (by any thread) after
7130** sqlite3_backup_init() is called and before the corresponding call to
7131** sqlite3_backup_finish().  SQLite does not currently check to see
7132** if the application incorrectly accesses the destination [database connection]
7133** and so no error code is reported, but the operations may malfunction
7134** nevertheless.  Use of the destination database connection while a
7135** backup is in progress might also also cause a mutex deadlock.
7136**
7137** If running in [shared cache mode], the application must
7138** guarantee that the shared cache used by the destination database
7139** is not accessed while the backup is running. In practice this means
7140** that the application must guarantee that the disk file being
7141** backed up to is not accessed by any connection within the process,
7142** not just the specific connection that was passed to sqlite3_backup_init().
7143**
7144** The [sqlite3_backup] object itself is partially threadsafe. Multiple
7145** threads may safely make multiple concurrent calls to sqlite3_backup_step().
7146** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
7147** APIs are not strictly speaking threadsafe. If they are invoked at the
7148** same time as another thread is invoking sqlite3_backup_step() it is
7149** possible that they return invalid values.
7150*/
7151SQLITE_API sqlite3_backup *SQLITE_STDCALL sqlite3_backup_init(
7152  sqlite3 *pDest,                        /* Destination database handle */
7153  const char *zDestName,                 /* Destination database name */
7154  sqlite3 *pSource,                      /* Source database handle */
7155  const char *zSourceName                /* Source database name */
7156);
7157SQLITE_API int SQLITE_STDCALL sqlite3_backup_step(sqlite3_backup *p, int nPage);
7158SQLITE_API int SQLITE_STDCALL sqlite3_backup_finish(sqlite3_backup *p);
7159SQLITE_API int SQLITE_STDCALL sqlite3_backup_remaining(sqlite3_backup *p);
7160SQLITE_API int SQLITE_STDCALL sqlite3_backup_pagecount(sqlite3_backup *p);
7161
7162/*
7163** CAPI3REF: Unlock Notification
7164** METHOD: sqlite3
7165**
7166** ^When running in shared-cache mode, a database operation may fail with
7167** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
7168** individual tables within the shared-cache cannot be obtained. See
7169** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
7170** ^This API may be used to register a callback that SQLite will invoke
7171** when the connection currently holding the required lock relinquishes it.
7172** ^This API is only available if the library was compiled with the
7173** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
7174**
7175** See Also: [Using the SQLite Unlock Notification Feature].
7176**
7177** ^Shared-cache locks are released when a database connection concludes
7178** its current transaction, either by committing it or rolling it back.
7179**
7180** ^When a connection (known as the blocked connection) fails to obtain a
7181** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
7182** identity of the database connection (the blocking connection) that
7183** has locked the required resource is stored internally. ^After an
7184** application receives an SQLITE_LOCKED error, it may call the
7185** sqlite3_unlock_notify() method with the blocked connection handle as
7186** the first argument to register for a callback that will be invoked
7187** when the blocking connections current transaction is concluded. ^The
7188** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
7189** call that concludes the blocking connections transaction.
7190**
7191** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
7192** there is a chance that the blocking connection will have already
7193** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
7194** If this happens, then the specified callback is invoked immediately,
7195** from within the call to sqlite3_unlock_notify().)^
7196**
7197** ^If the blocked connection is attempting to obtain a write-lock on a
7198** shared-cache table, and more than one other connection currently holds
7199** a read-lock on the same table, then SQLite arbitrarily selects one of
7200** the other connections to use as the blocking connection.
7201**
7202** ^(There may be at most one unlock-notify callback registered by a
7203** blocked connection. If sqlite3_unlock_notify() is called when the
7204** blocked connection already has a registered unlock-notify callback,
7205** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
7206** called with a NULL pointer as its second argument, then any existing
7207** unlock-notify callback is canceled. ^The blocked connections
7208** unlock-notify callback may also be canceled by closing the blocked
7209** connection using [sqlite3_close()].
7210**
7211** The unlock-notify callback is not reentrant. If an application invokes
7212** any sqlite3_xxx API functions from within an unlock-notify callback, a
7213** crash or deadlock may be the result.
7214**
7215** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
7216** returns SQLITE_OK.
7217**
7218** <b>Callback Invocation Details</b>
7219**
7220** When an unlock-notify callback is registered, the application provides a
7221** single void* pointer that is passed to the callback when it is invoked.
7222** However, the signature of the callback function allows SQLite to pass
7223** it an array of void* context pointers. The first argument passed to
7224** an unlock-notify callback is a pointer to an array of void* pointers,
7225** and the second is the number of entries in the array.
7226**
7227** When a blocking connections transaction is concluded, there may be
7228** more than one blocked connection that has registered for an unlock-notify
7229** callback. ^If two or more such blocked connections have specified the
7230** same callback function, then instead of invoking the callback function
7231** multiple times, it is invoked once with the set of void* context pointers
7232** specified by the blocked connections bundled together into an array.
7233** This gives the application an opportunity to prioritize any actions
7234** related to the set of unblocked database connections.
7235**
7236** <b>Deadlock Detection</b>
7237**
7238** Assuming that after registering for an unlock-notify callback a
7239** database waits for the callback to be issued before taking any further
7240** action (a reasonable assumption), then using this API may cause the
7241** application to deadlock. For example, if connection X is waiting for
7242** connection Y's transaction to be concluded, and similarly connection
7243** Y is waiting on connection X's transaction, then neither connection
7244** will proceed and the system may remain deadlocked indefinitely.
7245**
7246** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
7247** detection. ^If a given call to sqlite3_unlock_notify() would put the
7248** system in a deadlocked state, then SQLITE_LOCKED is returned and no
7249** unlock-notify callback is registered. The system is said to be in
7250** a deadlocked state if connection A has registered for an unlock-notify
7251** callback on the conclusion of connection B's transaction, and connection
7252** B has itself registered for an unlock-notify callback when connection
7253** A's transaction is concluded. ^Indirect deadlock is also detected, so
7254** the system is also considered to be deadlocked if connection B has
7255** registered for an unlock-notify callback on the conclusion of connection
7256** C's transaction, where connection C is waiting on connection A. ^Any
7257** number of levels of indirection are allowed.
7258**
7259** <b>The "DROP TABLE" Exception</b>
7260**
7261** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost
7262** always appropriate to call sqlite3_unlock_notify(). There is however,
7263** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
7264** SQLite checks if there are any currently executing SELECT statements
7265** that belong to the same connection. If there are, SQLITE_LOCKED is
7266** returned. In this case there is no "blocking connection", so invoking
7267** sqlite3_unlock_notify() results in the unlock-notify callback being
7268** invoked immediately. If the application then re-attempts the "DROP TABLE"
7269** or "DROP INDEX" query, an infinite loop might be the result.
7270**
7271** One way around this problem is to check the extended error code returned
7272** by an sqlite3_step() call. ^(If there is a blocking connection, then the
7273** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
7274** the special "DROP TABLE/INDEX" case, the extended error code is just
7275** SQLITE_LOCKED.)^
7276*/
7277SQLITE_API int SQLITE_STDCALL sqlite3_unlock_notify(
7278  sqlite3 *pBlocked,                          /* Waiting connection */
7279  void (*xNotify)(void **apArg, int nArg),    /* Callback function to invoke */
7280  void *pNotifyArg                            /* Argument to pass to xNotify */
7281);
7282
7283
7284/*
7285** CAPI3REF: String Comparison
7286**
7287** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications
7288** and extensions to compare the contents of two buffers containing UTF-8
7289** strings in a case-independent fashion, using the same definition of "case
7290** independence" that SQLite uses internally when comparing identifiers.
7291*/
7292SQLITE_API int SQLITE_STDCALL sqlite3_stricmp(const char *, const char *);
7293SQLITE_API int SQLITE_STDCALL sqlite3_strnicmp(const char *, const char *, int);
7294
7295/*
7296** CAPI3REF: String Globbing
7297*
7298** ^The [sqlite3_strglob(P,X)] interface returns zero if string X matches
7299** the glob pattern P, and it returns non-zero if string X does not match
7300** the glob pattern P.  ^The definition of glob pattern matching used in
7301** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the
7302** SQL dialect used by SQLite.  ^The sqlite3_strglob(P,X) function is case
7303** sensitive.
7304**
7305** Note that this routine returns zero on a match and non-zero if the strings
7306** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
7307*/
7308SQLITE_API int SQLITE_STDCALL sqlite3_strglob(const char *zGlob, const char *zStr);
7309
7310/*
7311** CAPI3REF: Error Logging Interface
7312**
7313** ^The [sqlite3_log()] interface writes a message into the [error log]
7314** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
7315** ^If logging is enabled, the zFormat string and subsequent arguments are
7316** used with [sqlite3_snprintf()] to generate the final output string.
7317**
7318** The sqlite3_log() interface is intended for use by extensions such as
7319** virtual tables, collating functions, and SQL functions.  While there is
7320** nothing to prevent an application from calling sqlite3_log(), doing so
7321** is considered bad form.
7322**
7323** The zFormat string must not be NULL.
7324**
7325** To avoid deadlocks and other threading problems, the sqlite3_log() routine
7326** will not use dynamically allocated memory.  The log message is stored in
7327** a fixed-length buffer on the stack.  If the log message is longer than
7328** a few hundred characters, it will be truncated to the length of the
7329** buffer.
7330*/
7331SQLITE_API void SQLITE_CDECL sqlite3_log(int iErrCode, const char *zFormat, ...);
7332
7333/*
7334** CAPI3REF: Write-Ahead Log Commit Hook
7335** METHOD: sqlite3
7336**
7337** ^The [sqlite3_wal_hook()] function is used to register a callback that
7338** is invoked each time data is committed to a database in wal mode.
7339**
7340** ^(The callback is invoked by SQLite after the commit has taken place and
7341** the associated write-lock on the database released)^, so the implementation
7342** may read, write or [checkpoint] the database as required.
7343**
7344** ^The first parameter passed to the callback function when it is invoked
7345** is a copy of the third parameter passed to sqlite3_wal_hook() when
7346** registering the callback. ^The second is a copy of the database handle.
7347** ^The third parameter is the name of the database that was written to -
7348** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
7349** is the number of pages currently in the write-ahead log file,
7350** including those that were just committed.
7351**
7352** The callback function should normally return [SQLITE_OK].  ^If an error
7353** code is returned, that error will propagate back up through the
7354** SQLite code base to cause the statement that provoked the callback
7355** to report an error, though the commit will have still occurred. If the
7356** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
7357** that does not correspond to any valid SQLite error code, the results
7358** are undefined.
7359**
7360** A single database handle may have at most a single write-ahead log callback
7361** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
7362** previously registered write-ahead log callback. ^Note that the
7363** [sqlite3_wal_autocheckpoint()] interface and the
7364** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
7365** those overwrite any prior [sqlite3_wal_hook()] settings.
7366*/
7367SQLITE_API void *SQLITE_STDCALL sqlite3_wal_hook(
7368  sqlite3*,
7369  int(*)(void *,sqlite3*,const char*,int),
7370  void*
7371);
7372
7373/*
7374** CAPI3REF: Configure an auto-checkpoint
7375** METHOD: sqlite3
7376**
7377** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
7378** [sqlite3_wal_hook()] that causes any database on [database connection] D
7379** to automatically [checkpoint]
7380** after committing a transaction if there are N or
7381** more frames in the [write-ahead log] file.  ^Passing zero or
7382** a negative value as the nFrame parameter disables automatic
7383** checkpoints entirely.
7384**
7385** ^The callback registered by this function replaces any existing callback
7386** registered using [sqlite3_wal_hook()].  ^Likewise, registering a callback
7387** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
7388** configured by this function.
7389**
7390** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
7391** from SQL.
7392**
7393** ^Checkpoints initiated by this mechanism are
7394** [sqlite3_wal_checkpoint_v2|PASSIVE].
7395**
7396** ^Every new [database connection] defaults to having the auto-checkpoint
7397** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
7398** pages.  The use of this interface
7399** is only necessary if the default setting is found to be suboptimal
7400** for a particular application.
7401*/
7402SQLITE_API int SQLITE_STDCALL sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
7403
7404/*
7405** CAPI3REF: Checkpoint a database
7406** METHOD: sqlite3
7407**
7408** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to
7409** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^
7410**
7411** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the
7412** [write-ahead log] for database X on [database connection] D to be
7413** transferred into the database file and for the write-ahead log to
7414** be reset.  See the [checkpointing] documentation for addition
7415** information.
7416**
7417** This interface used to be the only way to cause a checkpoint to
7418** occur.  But then the newer and more powerful [sqlite3_wal_checkpoint_v2()]
7419** interface was added.  This interface is retained for backwards
7420** compatibility and as a convenience for applications that need to manually
7421** start a callback but which do not need the full power (and corresponding
7422** complication) of [sqlite3_wal_checkpoint_v2()].
7423*/
7424SQLITE_API int SQLITE_STDCALL sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
7425
7426/*
7427** CAPI3REF: Checkpoint a database
7428** METHOD: sqlite3
7429**
7430** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint
7431** operation on database X of [database connection] D in mode M.  Status
7432** information is written back into integers pointed to by L and C.)^
7433** ^(The M parameter must be a valid [checkpoint mode]:)^
7434**
7435** <dl>
7436** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
7437**   ^Checkpoint as many frames as possible without waiting for any database
7438**   readers or writers to finish, then sync the database file if all frames
7439**   in the log were checkpointed. ^The [busy-handler callback]
7440**   is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode.
7441**   ^On the other hand, passive mode might leave the checkpoint unfinished
7442**   if there are concurrent readers or writers.
7443**
7444** <dt>SQLITE_CHECKPOINT_FULL<dd>
7445**   ^This mode blocks (it invokes the
7446**   [sqlite3_busy_handler|busy-handler callback]) until there is no
7447**   database writer and all readers are reading from the most recent database
7448**   snapshot. ^It then checkpoints all frames in the log file and syncs the
7449**   database file. ^This mode blocks new database writers while it is pending,
7450**   but new database readers are allowed to continue unimpeded.
7451**
7452** <dt>SQLITE_CHECKPOINT_RESTART<dd>
7453**   ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition
7454**   that after checkpointing the log file it blocks (calls the
7455**   [busy-handler callback])
7456**   until all readers are reading from the database file only. ^This ensures
7457**   that the next writer will restart the log file from the beginning.
7458**   ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new
7459**   database writer attempts while it is pending, but does not impede readers.
7460**
7461** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd>
7462**   ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the
7463**   addition that it also truncates the log file to zero bytes just prior
7464**   to a successful return.
7465** </dl>
7466**
7467** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in
7468** the log file or to -1 if the checkpoint could not run because
7469** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not
7470** NULL,then *pnCkpt is set to the total number of checkpointed frames in the
7471** log file (including any that were already checkpointed before the function
7472** was called) or to -1 if the checkpoint could not run due to an error or
7473** because the database is not in WAL mode. ^Note that upon successful
7474** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been
7475** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero.
7476**
7477** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If
7478** any other process is running a checkpoint operation at the same time, the
7479** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a
7480** busy-handler configured, it will not be invoked in this case.
7481**
7482** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the
7483** exclusive "writer" lock on the database file. ^If the writer lock cannot be
7484** obtained immediately, and a busy-handler is configured, it is invoked and
7485** the writer lock retried until either the busy-handler returns 0 or the lock
7486** is successfully obtained. ^The busy-handler is also invoked while waiting for
7487** database readers as described above. ^If the busy-handler returns 0 before
7488** the writer lock is obtained or while waiting for database readers, the
7489** checkpoint operation proceeds from that point in the same way as
7490** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible
7491** without blocking any further. ^SQLITE_BUSY is returned in this case.
7492**
7493** ^If parameter zDb is NULL or points to a zero length string, then the
7494** specified operation is attempted on all WAL databases [attached] to
7495** [database connection] db.  In this case the
7496** values written to output parameters *pnLog and *pnCkpt are undefined. ^If
7497** an SQLITE_BUSY error is encountered when processing one or more of the
7498** attached WAL databases, the operation is still attempted on any remaining
7499** attached databases and SQLITE_BUSY is returned at the end. ^If any other
7500** error occurs while processing an attached database, processing is abandoned
7501** and the error code is returned to the caller immediately. ^If no error
7502** (SQLITE_BUSY or otherwise) is encountered while processing the attached
7503** databases, SQLITE_OK is returned.
7504**
7505** ^If database zDb is the name of an attached database that is not in WAL
7506** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If
7507** zDb is not NULL (or a zero length string) and is not the name of any
7508** attached database, SQLITE_ERROR is returned to the caller.
7509**
7510** ^Unless it returns SQLITE_MISUSE,
7511** the sqlite3_wal_checkpoint_v2() interface
7512** sets the error information that is queried by
7513** [sqlite3_errcode()] and [sqlite3_errmsg()].
7514**
7515** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface
7516** from SQL.
7517*/
7518SQLITE_API int SQLITE_STDCALL sqlite3_wal_checkpoint_v2(
7519  sqlite3 *db,                    /* Database handle */
7520  const char *zDb,                /* Name of attached database (or NULL) */
7521  int eMode,                      /* SQLITE_CHECKPOINT_* value */
7522  int *pnLog,                     /* OUT: Size of WAL log in frames */
7523  int *pnCkpt                     /* OUT: Total number of frames checkpointed */
7524);
7525
7526/*
7527** CAPI3REF: Checkpoint Mode Values
7528** KEYWORDS: {checkpoint mode}
7529**
7530** These constants define all valid values for the "checkpoint mode" passed
7531** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface.
7532** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the
7533** meaning of each of these checkpoint modes.
7534*/
7535#define SQLITE_CHECKPOINT_PASSIVE  0  /* Do as much as possible w/o blocking */
7536#define SQLITE_CHECKPOINT_FULL     1  /* Wait for writers, then checkpoint */
7537#define SQLITE_CHECKPOINT_RESTART  2  /* Like FULL but wait for for readers */
7538#define SQLITE_CHECKPOINT_TRUNCATE 3  /* Like RESTART but also truncate WAL */
7539
7540/*
7541** CAPI3REF: Virtual Table Interface Configuration
7542**
7543** This function may be called by either the [xConnect] or [xCreate] method
7544** of a [virtual table] implementation to configure
7545** various facets of the virtual table interface.
7546**
7547** If this interface is invoked outside the context of an xConnect or
7548** xCreate virtual table method then the behavior is undefined.
7549**
7550** At present, there is only one option that may be configured using
7551** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].)  Further options
7552** may be added in the future.
7553*/
7554SQLITE_API int SQLITE_CDECL sqlite3_vtab_config(sqlite3*, int op, ...);
7555
7556/*
7557** CAPI3REF: Virtual Table Configuration Options
7558**
7559** These macros define the various options to the
7560** [sqlite3_vtab_config()] interface that [virtual table] implementations
7561** can use to customize and optimize their behavior.
7562**
7563** <dl>
7564** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT
7565** <dd>Calls of the form
7566** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
7567** where X is an integer.  If X is zero, then the [virtual table] whose
7568** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not
7569** support constraints.  In this configuration (which is the default) if
7570** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire
7571** statement is rolled back as if [ON CONFLICT | OR ABORT] had been
7572** specified as part of the users SQL statement, regardless of the actual
7573** ON CONFLICT mode specified.
7574**
7575** If X is non-zero, then the virtual table implementation guarantees
7576** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before
7577** any modifications to internal or persistent data structures have been made.
7578** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite
7579** is able to roll back a statement or database transaction, and abandon
7580** or continue processing the current SQL statement as appropriate.
7581** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns
7582** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode
7583** had been ABORT.
7584**
7585** Virtual table implementations that are required to handle OR REPLACE
7586** must do so within the [xUpdate] method. If a call to the
7587** [sqlite3_vtab_on_conflict()] function indicates that the current ON
7588** CONFLICT policy is REPLACE, the virtual table implementation should
7589** silently replace the appropriate rows within the xUpdate callback and
7590** return SQLITE_OK. Or, if this is not possible, it may return
7591** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT
7592** constraint handling.
7593** </dl>
7594*/
7595#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1
7596
7597/*
7598** CAPI3REF: Determine The Virtual Table Conflict Policy
7599**
7600** This function may only be called from within a call to the [xUpdate] method
7601** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The
7602** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
7603** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
7604** of the SQL statement that triggered the call to the [xUpdate] method of the
7605** [virtual table].
7606*/
7607SQLITE_API int SQLITE_STDCALL sqlite3_vtab_on_conflict(sqlite3 *);
7608
7609/*
7610** CAPI3REF: Conflict resolution modes
7611** KEYWORDS: {conflict resolution mode}
7612**
7613** These constants are returned by [sqlite3_vtab_on_conflict()] to
7614** inform a [virtual table] implementation what the [ON CONFLICT] mode
7615** is for the SQL statement being evaluated.
7616**
7617** Note that the [SQLITE_IGNORE] constant is also used as a potential
7618** return value from the [sqlite3_set_authorizer()] callback and that
7619** [SQLITE_ABORT] is also a [result code].
7620*/
7621#define SQLITE_ROLLBACK 1
7622/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
7623#define SQLITE_FAIL     3
7624/* #define SQLITE_ABORT 4  // Also an error code */
7625#define SQLITE_REPLACE  5
7626
7627/*
7628** CAPI3REF: Prepared Statement Scan Status Opcodes
7629** KEYWORDS: {scanstatus options}
7630**
7631** The following constants can be used for the T parameter to the
7632** [sqlite3_stmt_scanstatus(S,X,T,V)] interface.  Each constant designates a
7633** different metric for sqlite3_stmt_scanstatus() to return.
7634**
7635** When the value returned to V is a string, space to hold that string is
7636** managed by the prepared statement S and will be automatically freed when
7637** S is finalized.
7638**
7639** <dl>
7640** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt>
7641** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be
7642** set to the total number of times that the X-th loop has run.</dd>
7643**
7644** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt>
7645** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set
7646** to the total number of rows examined by all iterations of the X-th loop.</dd>
7647**
7648** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt>
7649** <dd>^The "double" variable pointed to by the T parameter will be set to the
7650** query planner's estimate for the average number of rows output from each
7651** iteration of the X-th loop.  If the query planner's estimates was accurate,
7652** then this value will approximate the quotient NVISIT/NLOOP and the
7653** product of this value for all prior loops with the same SELECTID will
7654** be the NLOOP value for the current loop.
7655**
7656** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt>
7657** <dd>^The "const char *" variable pointed to by the T parameter will be set
7658** to a zero-terminated UTF-8 string containing the name of the index or table
7659** used for the X-th loop.
7660**
7661** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt>
7662** <dd>^The "const char *" variable pointed to by the T parameter will be set
7663** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN]
7664** description for the X-th loop.
7665**
7666** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt>
7667** <dd>^The "int" variable pointed to by the T parameter will be set to the
7668** "select-id" for the X-th loop.  The select-id identifies which query or
7669** subquery the loop is part of.  The main query has a select-id of zero.
7670** The select-id is the same value as is output in the first column
7671** of an [EXPLAIN QUERY PLAN] query.
7672** </dl>
7673*/
7674#define SQLITE_SCANSTAT_NLOOP    0
7675#define SQLITE_SCANSTAT_NVISIT   1
7676#define SQLITE_SCANSTAT_EST      2
7677#define SQLITE_SCANSTAT_NAME     3
7678#define SQLITE_SCANSTAT_EXPLAIN  4
7679#define SQLITE_SCANSTAT_SELECTID 5
7680
7681/*
7682** CAPI3REF: Prepared Statement Scan Status
7683** METHOD: sqlite3_stmt
7684**
7685** This interface returns information about the predicted and measured
7686** performance for pStmt.  Advanced applications can use this
7687** interface to compare the predicted and the measured performance and
7688** issue warnings and/or rerun [ANALYZE] if discrepancies are found.
7689**
7690** Since this interface is expected to be rarely used, it is only
7691** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS]
7692** compile-time option.
7693**
7694** The "iScanStatusOp" parameter determines which status information to return.
7695** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior
7696** of this interface is undefined.
7697** ^The requested measurement is written into a variable pointed to by
7698** the "pOut" parameter.
7699** Parameter "idx" identifies the specific loop to retrieve statistics for.
7700** Loops are numbered starting from zero. ^If idx is out of range - less than
7701** zero or greater than or equal to the total number of loops used to implement
7702** the statement - a non-zero value is returned and the variable that pOut
7703** points to is unchanged.
7704**
7705** ^Statistics might not be available for all loops in all statements. ^In cases
7706** where there exist loops with no available statistics, this function behaves
7707** as if the loop did not exist - it returns non-zero and leave the variable
7708** that pOut points to unchanged.
7709**
7710** See also: [sqlite3_stmt_scanstatus_reset()]
7711*/
7712SQLITE_API int SQLITE_STDCALL sqlite3_stmt_scanstatus(
7713  sqlite3_stmt *pStmt,      /* Prepared statement for which info desired */
7714  int idx,                  /* Index of loop to report on */
7715  int iScanStatusOp,        /* Information desired.  SQLITE_SCANSTAT_* */
7716  void *pOut                /* Result written here */
7717);
7718
7719/*
7720** CAPI3REF: Zero Scan-Status Counters
7721** METHOD: sqlite3_stmt
7722**
7723** ^Zero all [sqlite3_stmt_scanstatus()] related event counters.
7724**
7725** This API is only available if the library is built with pre-processor
7726** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined.
7727*/
7728SQLITE_API void SQLITE_STDCALL sqlite3_stmt_scanstatus_reset(sqlite3_stmt*);
7729
7730
7731/*
7732** Undo the hack that converts floating point types to integer for
7733** builds on processors without floating point support.
7734*/
7735#ifdef SQLITE_OMIT_FLOATING_POINT
7736# undef double
7737#endif
7738
7739#ifdef __cplusplus
7740}  /* End of the 'extern "C"' block */
7741#endif
7742#endif /* _SQLITE3_H_ */
7743
7744/*
7745** 2010 August 30
7746**
7747** The author disclaims copyright to this source code.  In place of
7748** a legal notice, here is a blessing:
7749**
7750**    May you do good and not evil.
7751**    May you find forgiveness for yourself and forgive others.
7752**    May you share freely, never taking more than you give.
7753**
7754*************************************************************************
7755*/
7756
7757#ifndef _SQLITE3RTREE_H_
7758#define _SQLITE3RTREE_H_
7759
7760
7761#ifdef __cplusplus
7762extern "C" {
7763#endif
7764
7765typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry;
7766typedef struct sqlite3_rtree_query_info sqlite3_rtree_query_info;
7767
7768/* The double-precision datatype used by RTree depends on the
7769** SQLITE_RTREE_INT_ONLY compile-time option.
7770*/
7771#ifdef SQLITE_RTREE_INT_ONLY
7772  typedef sqlite3_int64 sqlite3_rtree_dbl;
7773#else
7774  typedef double sqlite3_rtree_dbl;
7775#endif
7776
7777/*
7778** Register a geometry callback named zGeom that can be used as part of an
7779** R-Tree geometry query as follows:
7780**
7781**   SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...)
7782*/
7783SQLITE_API int SQLITE_STDCALL sqlite3_rtree_geometry_callback(
7784  sqlite3 *db,
7785  const char *zGeom,
7786  int (*xGeom)(sqlite3_rtree_geometry*, int, sqlite3_rtree_dbl*,int*),
7787  void *pContext
7788);
7789
7790
7791/*
7792** A pointer to a structure of the following type is passed as the first
7793** argument to callbacks registered using rtree_geometry_callback().
7794*/
7795struct sqlite3_rtree_geometry {
7796  void *pContext;                 /* Copy of pContext passed to s_r_g_c() */
7797  int nParam;                     /* Size of array aParam[] */
7798  sqlite3_rtree_dbl *aParam;      /* Parameters passed to SQL geom function */
7799  void *pUser;                    /* Callback implementation user data */
7800  void (*xDelUser)(void *);       /* Called by SQLite to clean up pUser */
7801};
7802
7803/*
7804** Register a 2nd-generation geometry callback named zScore that can be
7805** used as part of an R-Tree geometry query as follows:
7806**
7807**   SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zQueryFunc(... params ...)
7808*/
7809SQLITE_API int SQLITE_STDCALL sqlite3_rtree_query_callback(
7810  sqlite3 *db,
7811  const char *zQueryFunc,
7812  int (*xQueryFunc)(sqlite3_rtree_query_info*),
7813  void *pContext,
7814  void (*xDestructor)(void*)
7815);
7816
7817
7818/*
7819** A pointer to a structure of the following type is passed as the
7820** argument to scored geometry callback registered using
7821** sqlite3_rtree_query_callback().
7822**
7823** Note that the first 5 fields of this structure are identical to
7824** sqlite3_rtree_geometry.  This structure is a subclass of
7825** sqlite3_rtree_geometry.
7826*/
7827struct sqlite3_rtree_query_info {
7828  void *pContext;                   /* pContext from when function registered */
7829  int nParam;                       /* Number of function parameters */
7830  sqlite3_rtree_dbl *aParam;        /* value of function parameters */
7831  void *pUser;                      /* callback can use this, if desired */
7832  void (*xDelUser)(void*);          /* function to free pUser */
7833  sqlite3_rtree_dbl *aCoord;        /* Coordinates of node or entry to check */
7834  unsigned int *anQueue;            /* Number of pending entries in the queue */
7835  int nCoord;                       /* Number of coordinates */
7836  int iLevel;                       /* Level of current node or entry */
7837  int mxLevel;                      /* The largest iLevel value in the tree */
7838  sqlite3_int64 iRowid;             /* Rowid for current entry */
7839  sqlite3_rtree_dbl rParentScore;   /* Score of parent node */
7840  int eParentWithin;                /* Visibility of parent node */
7841  int eWithin;                      /* OUT: Visiblity */
7842  sqlite3_rtree_dbl rScore;         /* OUT: Write the score here */
7843  /* The following fields are only available in 3.8.11 and later */
7844  sqlite3_value **apSqlParam;       /* Original SQL values of parameters */
7845};
7846
7847/*
7848** Allowed values for sqlite3_rtree_query.eWithin and .eParentWithin.
7849*/
7850#define NOT_WITHIN       0   /* Object completely outside of query region */
7851#define PARTLY_WITHIN    1   /* Object partially overlaps query region */
7852#define FULLY_WITHIN     2   /* Object fully contained within query region */
7853
7854
7855#ifdef __cplusplus
7856}  /* end of the 'extern "C"' block */
7857#endif
7858
7859#endif  /* ifndef _SQLITE3RTREE_H_ */
7860
7861