sqlite3.h revision 282328
1/*
2** 2001 September 15
3**
4** The author disclaims copyright to this source code.  In place of
5** a legal notice, here is a blessing:
6**
7**    May you do good and not evil.
8**    May you find forgiveness for yourself and forgive others.
9**    May you share freely, never taking more than you give.
10**
11*************************************************************************
12** This header file defines the interface that the SQLite library
13** presents to client programs.  If a C-function, structure, datatype,
14** or constant definition does not appear in this file, then it is
15** not a published API of SQLite, is subject to change without
16** notice, and should not be referenced by programs that use SQLite.
17**
18** Some of the definitions that are in this file are marked as
19** "experimental".  Experimental interfaces are normally new
20** features recently added to SQLite.  We do not anticipate changes
21** to experimental interfaces but reserve the right to make minor changes
22** if experience from use "in the wild" suggest such changes are prudent.
23**
24** The official C-language API documentation for SQLite is derived
25** from comments in this file.  This file is the authoritative source
26** on how SQLite interfaces are suppose to operate.
27**
28** The name of this file under configuration management is "sqlite.h.in".
29** The makefile makes some minor changes to this file (such as inserting
30** the version number) and changes its name to "sqlite3.h" as
31** part of the build process.
32*/
33#ifndef _SQLITE3_H_
34#define _SQLITE3_H_
35#include <stdarg.h>     /* Needed for the definition of va_list */
36
37/*
38** Make sure we can call this stuff from C++.
39*/
40#ifdef __cplusplus
41extern "C" {
42#endif
43
44
45/*
46** 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        "3.8.9"
115#define SQLITE_VERSION_NUMBER 3008009
116#define SQLITE_SOURCE_ID      "2015-04-08 12:16:33 8a8ffc862e96f57aa698f93de10dee28e69f6e09"
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**
274** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors
275** for the [sqlite3] object.
276** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if
277** the [sqlite3] object is successfully destroyed and all associated
278** resources are deallocated.
279**
280** ^If the database connection is associated with unfinalized prepared
281** statements or unfinished sqlite3_backup objects then sqlite3_close()
282** will leave the database connection open and return [SQLITE_BUSY].
283** ^If sqlite3_close_v2() is called with unfinalized prepared statements
284** and/or unfinished sqlite3_backups, then the database connection becomes
285** an unusable "zombie" which will automatically be deallocated when the
286** last prepared statement is finalized or the last sqlite3_backup is
287** finished.  The sqlite3_close_v2() interface is intended for use with
288** host languages that are garbage collected, and where the order in which
289** destructors are called is arbitrary.
290**
291** Applications should [sqlite3_finalize | finalize] all [prepared statements],
292** [sqlite3_blob_close | close] all [BLOB handles], and
293** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated
294** with the [sqlite3] object prior to attempting to close the object.  ^If
295** sqlite3_close_v2() is called on a [database connection] that still has
296** outstanding [prepared statements], [BLOB handles], and/or
297** [sqlite3_backup] objects then it returns [SQLITE_OK] and the deallocation
298** of resources is deferred until all [prepared statements], [BLOB handles],
299** and [sqlite3_backup] objects are also destroyed.
300**
301** ^If an [sqlite3] object is destroyed while a transaction is open,
302** the transaction is automatically rolled back.
303**
304** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)]
305** must be either a NULL
306** pointer or an [sqlite3] object pointer obtained
307** from [sqlite3_open()], [sqlite3_open16()], or
308** [sqlite3_open_v2()], and not previously closed.
309** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer
310** argument is a harmless no-op.
311*/
312SQLITE_API int SQLITE_STDCALL sqlite3_close(sqlite3*);
313SQLITE_API int SQLITE_STDCALL sqlite3_close_v2(sqlite3*);
314
315/*
316** The type for a callback function.
317** This is legacy and deprecated.  It is included for historical
318** compatibility and is not documented.
319*/
320typedef int (*sqlite3_callback)(void*,int,char**, char**);
321
322/*
323** CAPI3REF: One-Step Query Execution Interface
324**
325** The sqlite3_exec() interface is a convenience wrapper around
326** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
327** that allows an application to run multiple statements of SQL
328** without having to use a lot of C code.
329**
330** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
331** semicolon-separate SQL statements passed into its 2nd argument,
332** in the context of the [database connection] passed in as its 1st
333** argument.  ^If the callback function of the 3rd argument to
334** sqlite3_exec() is not NULL, then it is invoked for each result row
335** coming out of the evaluated SQL statements.  ^The 4th argument to
336** sqlite3_exec() is relayed through to the 1st argument of each
337** callback invocation.  ^If the callback pointer to sqlite3_exec()
338** is NULL, then no callback is ever invoked and result rows are
339** ignored.
340**
341** ^If an error occurs while evaluating the SQL statements passed into
342** sqlite3_exec(), then execution of the current statement stops and
343** subsequent statements are skipped.  ^If the 5th parameter to sqlite3_exec()
344** is not NULL then any error message is written into memory obtained
345** from [sqlite3_malloc()] and passed back through the 5th parameter.
346** To avoid memory leaks, the application should invoke [sqlite3_free()]
347** on error message strings returned through the 5th parameter of
348** of sqlite3_exec() after the error message string is no longer needed.
349** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
350** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
351** NULL before returning.
352**
353** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
354** routine returns SQLITE_ABORT without invoking the callback again and
355** without running any subsequent SQL statements.
356**
357** ^The 2nd argument to the sqlite3_exec() callback function is the
358** number of columns in the result.  ^The 3rd argument to the sqlite3_exec()
359** callback is an array of pointers to strings obtained as if from
360** [sqlite3_column_text()], one for each column.  ^If an element of a
361** result row is NULL then the corresponding string pointer for the
362** sqlite3_exec() callback is a NULL pointer.  ^The 4th argument to the
363** sqlite3_exec() callback is an array of pointers to strings where each
364** entry represents the name of corresponding result column as obtained
365** from [sqlite3_column_name()].
366**
367** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
368** to an empty string, or a pointer that contains only whitespace and/or
369** SQL comments, then no SQL statements are evaluated and the database
370** is not changed.
371**
372** Restrictions:
373**
374** <ul>
375** <li> The application must insure that the 1st parameter to sqlite3_exec()
376**      is a valid and open [database connection].
377** <li> The application must not close the [database connection] specified by
378**      the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
379** <li> The application must not modify the SQL statement text passed into
380**      the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
381** </ul>
382*/
383SQLITE_API int SQLITE_STDCALL sqlite3_exec(
384  sqlite3*,                                  /* An open database */
385  const char *sql,                           /* SQL to be evaluated */
386  int (*callback)(void*,int,char**,char**),  /* Callback function */
387  void *,                                    /* 1st argument to callback */
388  char **errmsg                              /* Error msg written here */
389);
390
391/*
392** CAPI3REF: Result Codes
393** KEYWORDS: {result code definitions}
394**
395** Many SQLite functions return an integer result code from the set shown
396** here in order to indicate success or failure.
397**
398** New error codes may be added in future versions of SQLite.
399**
400** See also: [extended result code definitions]
401*/
402#define SQLITE_OK           0   /* Successful result */
403/* beginning-of-error-codes */
404#define SQLITE_ERROR        1   /* SQL error or missing database */
405#define SQLITE_INTERNAL     2   /* Internal logic error in SQLite */
406#define SQLITE_PERM         3   /* Access permission denied */
407#define SQLITE_ABORT        4   /* Callback routine requested an abort */
408#define SQLITE_BUSY         5   /* The database file is locked */
409#define SQLITE_LOCKED       6   /* A table in the database is locked */
410#define SQLITE_NOMEM        7   /* A malloc() failed */
411#define SQLITE_READONLY     8   /* Attempt to write a readonly database */
412#define SQLITE_INTERRUPT    9   /* Operation terminated by sqlite3_interrupt()*/
413#define SQLITE_IOERR       10   /* Some kind of disk I/O error occurred */
414#define SQLITE_CORRUPT     11   /* The database disk image is malformed */
415#define SQLITE_NOTFOUND    12   /* Unknown opcode in sqlite3_file_control() */
416#define SQLITE_FULL        13   /* Insertion failed because database is full */
417#define SQLITE_CANTOPEN    14   /* Unable to open the database file */
418#define SQLITE_PROTOCOL    15   /* Database lock protocol error */
419#define SQLITE_EMPTY       16   /* Database is empty */
420#define SQLITE_SCHEMA      17   /* The database schema changed */
421#define SQLITE_TOOBIG      18   /* String or BLOB exceeds size limit */
422#define SQLITE_CONSTRAINT  19   /* Abort due to constraint violation */
423#define SQLITE_MISMATCH    20   /* Data type mismatch */
424#define SQLITE_MISUSE      21   /* Library used incorrectly */
425#define SQLITE_NOLFS       22   /* Uses OS features not supported on host */
426#define SQLITE_AUTH        23   /* Authorization denied */
427#define SQLITE_FORMAT      24   /* Auxiliary database format error */
428#define SQLITE_RANGE       25   /* 2nd parameter to sqlite3_bind out of range */
429#define SQLITE_NOTADB      26   /* File opened that is not a database file */
430#define SQLITE_NOTICE      27   /* Notifications from sqlite3_log() */
431#define SQLITE_WARNING     28   /* Warnings from sqlite3_log() */
432#define SQLITE_ROW         100  /* sqlite3_step() has another row ready */
433#define SQLITE_DONE        101  /* sqlite3_step() has finished executing */
434/* end-of-error-codes */
435
436/*
437** CAPI3REF: Extended Result Codes
438** KEYWORDS: {extended result code definitions}
439**
440** In its default configuration, SQLite API routines return one of 30 integer
441** [result codes].  However, experience has shown that many of
442** these result codes are too coarse-grained.  They do not provide as
443** much information about problems as programmers might like.  In an effort to
444** address this, newer versions of SQLite (version 3.3.8 and later) include
445** support for additional result codes that provide more detailed information
446** about errors. These [extended result codes] are enabled or disabled
447** on a per database connection basis using the
448** [sqlite3_extended_result_codes()] API.  Or, the extended code for
449** the most recent error can be obtained using
450** [sqlite3_extended_errcode()].
451*/
452#define SQLITE_IOERR_READ              (SQLITE_IOERR | (1<<8))
453#define SQLITE_IOERR_SHORT_READ        (SQLITE_IOERR | (2<<8))
454#define SQLITE_IOERR_WRITE             (SQLITE_IOERR | (3<<8))
455#define SQLITE_IOERR_FSYNC             (SQLITE_IOERR | (4<<8))
456#define SQLITE_IOERR_DIR_FSYNC         (SQLITE_IOERR | (5<<8))
457#define SQLITE_IOERR_TRUNCATE          (SQLITE_IOERR | (6<<8))
458#define SQLITE_IOERR_FSTAT             (SQLITE_IOERR | (7<<8))
459#define SQLITE_IOERR_UNLOCK            (SQLITE_IOERR | (8<<8))
460#define SQLITE_IOERR_RDLOCK            (SQLITE_IOERR | (9<<8))
461#define SQLITE_IOERR_DELETE            (SQLITE_IOERR | (10<<8))
462#define SQLITE_IOERR_BLOCKED           (SQLITE_IOERR | (11<<8))
463#define SQLITE_IOERR_NOMEM             (SQLITE_IOERR | (12<<8))
464#define SQLITE_IOERR_ACCESS            (SQLITE_IOERR | (13<<8))
465#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
466#define SQLITE_IOERR_LOCK              (SQLITE_IOERR | (15<<8))
467#define SQLITE_IOERR_CLOSE             (SQLITE_IOERR | (16<<8))
468#define SQLITE_IOERR_DIR_CLOSE         (SQLITE_IOERR | (17<<8))
469#define SQLITE_IOERR_SHMOPEN           (SQLITE_IOERR | (18<<8))
470#define SQLITE_IOERR_SHMSIZE           (SQLITE_IOERR | (19<<8))
471#define SQLITE_IOERR_SHMLOCK           (SQLITE_IOERR | (20<<8))
472#define SQLITE_IOERR_SHMMAP            (SQLITE_IOERR | (21<<8))
473#define SQLITE_IOERR_SEEK              (SQLITE_IOERR | (22<<8))
474#define SQLITE_IOERR_DELETE_NOENT      (SQLITE_IOERR | (23<<8))
475#define SQLITE_IOERR_MMAP              (SQLITE_IOERR | (24<<8))
476#define SQLITE_IOERR_GETTEMPPATH       (SQLITE_IOERR | (25<<8))
477#define SQLITE_IOERR_CONVPATH          (SQLITE_IOERR | (26<<8))
478#define SQLITE_LOCKED_SHAREDCACHE      (SQLITE_LOCKED |  (1<<8))
479#define SQLITE_BUSY_RECOVERY           (SQLITE_BUSY   |  (1<<8))
480#define SQLITE_BUSY_SNAPSHOT           (SQLITE_BUSY   |  (2<<8))
481#define SQLITE_CANTOPEN_NOTEMPDIR      (SQLITE_CANTOPEN | (1<<8))
482#define SQLITE_CANTOPEN_ISDIR          (SQLITE_CANTOPEN | (2<<8))
483#define SQLITE_CANTOPEN_FULLPATH       (SQLITE_CANTOPEN | (3<<8))
484#define SQLITE_CANTOPEN_CONVPATH       (SQLITE_CANTOPEN | (4<<8))
485#define SQLITE_CORRUPT_VTAB            (SQLITE_CORRUPT | (1<<8))
486#define SQLITE_READONLY_RECOVERY       (SQLITE_READONLY | (1<<8))
487#define SQLITE_READONLY_CANTLOCK       (SQLITE_READONLY | (2<<8))
488#define SQLITE_READONLY_ROLLBACK       (SQLITE_READONLY | (3<<8))
489#define SQLITE_READONLY_DBMOVED        (SQLITE_READONLY | (4<<8))
490#define SQLITE_ABORT_ROLLBACK          (SQLITE_ABORT | (2<<8))
491#define SQLITE_CONSTRAINT_CHECK        (SQLITE_CONSTRAINT | (1<<8))
492#define SQLITE_CONSTRAINT_COMMITHOOK   (SQLITE_CONSTRAINT | (2<<8))
493#define SQLITE_CONSTRAINT_FOREIGNKEY   (SQLITE_CONSTRAINT | (3<<8))
494#define SQLITE_CONSTRAINT_FUNCTION     (SQLITE_CONSTRAINT | (4<<8))
495#define SQLITE_CONSTRAINT_NOTNULL      (SQLITE_CONSTRAINT | (5<<8))
496#define SQLITE_CONSTRAINT_PRIMARYKEY   (SQLITE_CONSTRAINT | (6<<8))
497#define SQLITE_CONSTRAINT_TRIGGER      (SQLITE_CONSTRAINT | (7<<8))
498#define SQLITE_CONSTRAINT_UNIQUE       (SQLITE_CONSTRAINT | (8<<8))
499#define SQLITE_CONSTRAINT_VTAB         (SQLITE_CONSTRAINT | (9<<8))
500#define SQLITE_CONSTRAINT_ROWID        (SQLITE_CONSTRAINT |(10<<8))
501#define SQLITE_NOTICE_RECOVER_WAL      (SQLITE_NOTICE | (1<<8))
502#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8))
503#define SQLITE_WARNING_AUTOINDEX       (SQLITE_WARNING | (1<<8))
504#define SQLITE_AUTH_USER               (SQLITE_AUTH | (1<<8))
505
506/*
507** CAPI3REF: Flags For File Open Operations
508**
509** These bit values are intended for use in the
510** 3rd parameter to the [sqlite3_open_v2()] interface and
511** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
512*/
513#define SQLITE_OPEN_READONLY         0x00000001  /* Ok for sqlite3_open_v2() */
514#define SQLITE_OPEN_READWRITE        0x00000002  /* Ok for sqlite3_open_v2() */
515#define SQLITE_OPEN_CREATE           0x00000004  /* Ok for sqlite3_open_v2() */
516#define SQLITE_OPEN_DELETEONCLOSE    0x00000008  /* VFS only */
517#define SQLITE_OPEN_EXCLUSIVE        0x00000010  /* VFS only */
518#define SQLITE_OPEN_AUTOPROXY        0x00000020  /* VFS only */
519#define SQLITE_OPEN_URI              0x00000040  /* Ok for sqlite3_open_v2() */
520#define SQLITE_OPEN_MEMORY           0x00000080  /* Ok for sqlite3_open_v2() */
521#define SQLITE_OPEN_MAIN_DB          0x00000100  /* VFS only */
522#define SQLITE_OPEN_TEMP_DB          0x00000200  /* VFS only */
523#define SQLITE_OPEN_TRANSIENT_DB     0x00000400  /* VFS only */
524#define SQLITE_OPEN_MAIN_JOURNAL     0x00000800  /* VFS only */
525#define SQLITE_OPEN_TEMP_JOURNAL     0x00001000  /* VFS only */
526#define SQLITE_OPEN_SUBJOURNAL       0x00002000  /* VFS only */
527#define SQLITE_OPEN_MASTER_JOURNAL   0x00004000  /* VFS only */
528#define SQLITE_OPEN_NOMUTEX          0x00008000  /* Ok for sqlite3_open_v2() */
529#define SQLITE_OPEN_FULLMUTEX        0x00010000  /* Ok for sqlite3_open_v2() */
530#define SQLITE_OPEN_SHAREDCACHE      0x00020000  /* Ok for sqlite3_open_v2() */
531#define SQLITE_OPEN_PRIVATECACHE     0x00040000  /* Ok for sqlite3_open_v2() */
532#define SQLITE_OPEN_WAL              0x00080000  /* VFS only */
533
534/* Reserved:                         0x00F00000 */
535
536/*
537** CAPI3REF: Device Characteristics
538**
539** The xDeviceCharacteristics method of the [sqlite3_io_methods]
540** object returns an integer which is a vector of these
541** bit values expressing I/O characteristics of the mass storage
542** device that holds the file that the [sqlite3_io_methods]
543** refers to.
544**
545** The SQLITE_IOCAP_ATOMIC property means that all writes of
546** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
547** mean that writes of blocks that are nnn bytes in size and
548** are aligned to an address which is an integer multiple of
549** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
550** that when data is appended to a file, the data is appended
551** first then the size of the file is extended, never the other
552** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
553** information is written to disk in the same order as calls
554** to xWrite().  The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
555** after reboot following a crash or power loss, the only bytes in a
556** file that were written at the application level might have changed
557** and that adjacent bytes, even bytes within the same sector are
558** guaranteed to be unchanged.  The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN
559** flag indicate that a file cannot be deleted when open.  The
560** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on
561** read-only media and cannot be changed even by processes with
562** elevated privileges.
563*/
564#define SQLITE_IOCAP_ATOMIC                 0x00000001
565#define SQLITE_IOCAP_ATOMIC512              0x00000002
566#define SQLITE_IOCAP_ATOMIC1K               0x00000004
567#define SQLITE_IOCAP_ATOMIC2K               0x00000008
568#define SQLITE_IOCAP_ATOMIC4K               0x00000010
569#define SQLITE_IOCAP_ATOMIC8K               0x00000020
570#define SQLITE_IOCAP_ATOMIC16K              0x00000040
571#define SQLITE_IOCAP_ATOMIC32K              0x00000080
572#define SQLITE_IOCAP_ATOMIC64K              0x00000100
573#define SQLITE_IOCAP_SAFE_APPEND            0x00000200
574#define SQLITE_IOCAP_SEQUENTIAL             0x00000400
575#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN  0x00000800
576#define SQLITE_IOCAP_POWERSAFE_OVERWRITE    0x00001000
577#define SQLITE_IOCAP_IMMUTABLE              0x00002000
578
579/*
580** CAPI3REF: File Locking Levels
581**
582** SQLite uses one of these integer values as the second
583** argument to calls it makes to the xLock() and xUnlock() methods
584** of an [sqlite3_io_methods] object.
585*/
586#define SQLITE_LOCK_NONE          0
587#define SQLITE_LOCK_SHARED        1
588#define SQLITE_LOCK_RESERVED      2
589#define SQLITE_LOCK_PENDING       3
590#define SQLITE_LOCK_EXCLUSIVE     4
591
592/*
593** CAPI3REF: Synchronization Type Flags
594**
595** When SQLite invokes the xSync() method of an
596** [sqlite3_io_methods] object it uses a combination of
597** these integer values as the second argument.
598**
599** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
600** sync operation only needs to flush data to mass storage.  Inode
601** information need not be flushed. If the lower four bits of the flag
602** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
603** If the lower four bits equal SQLITE_SYNC_FULL, that means
604** to use Mac OS X style fullsync instead of fsync().
605**
606** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
607** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
608** settings.  The [synchronous pragma] determines when calls to the
609** xSync VFS method occur and applies uniformly across all platforms.
610** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
611** energetic or rigorous or forceful the sync operations are and
612** only make a difference on Mac OSX for the default SQLite code.
613** (Third-party VFS implementations might also make the distinction
614** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
615** operating systems natively supported by SQLite, only Mac OSX
616** cares about the difference.)
617*/
618#define SQLITE_SYNC_NORMAL        0x00002
619#define SQLITE_SYNC_FULL          0x00003
620#define SQLITE_SYNC_DATAONLY      0x00010
621
622/*
623** CAPI3REF: OS Interface Open File Handle
624**
625** An [sqlite3_file] object represents an open file in the
626** [sqlite3_vfs | OS interface layer].  Individual OS interface
627** implementations will
628** want to subclass this object by appending additional fields
629** for their own use.  The pMethods entry is a pointer to an
630** [sqlite3_io_methods] object that defines methods for performing
631** I/O operations on the open file.
632*/
633typedef struct sqlite3_file sqlite3_file;
634struct sqlite3_file {
635  const struct sqlite3_io_methods *pMethods;  /* Methods for an open file */
636};
637
638/*
639** CAPI3REF: OS Interface File Virtual Methods Object
640**
641** Every file opened by the [sqlite3_vfs.xOpen] method populates an
642** [sqlite3_file] object (or, more commonly, a subclass of the
643** [sqlite3_file] object) with a pointer to an instance of this object.
644** This object defines the methods used to perform various operations
645** against the open file represented by the [sqlite3_file] object.
646**
647** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element
648** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
649** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed.  The
650** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
651** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
652** to NULL.
653**
654** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
655** [SQLITE_SYNC_FULL].  The first choice is the normal fsync().
656** The second choice is a Mac OS X style fullsync.  The [SQLITE_SYNC_DATAONLY]
657** flag may be ORed in to indicate that only the data of the file
658** and not its inode needs to be synced.
659**
660** The integer values to xLock() and xUnlock() are one of
661** <ul>
662** <li> [SQLITE_LOCK_NONE],
663** <li> [SQLITE_LOCK_SHARED],
664** <li> [SQLITE_LOCK_RESERVED],
665** <li> [SQLITE_LOCK_PENDING], or
666** <li> [SQLITE_LOCK_EXCLUSIVE].
667** </ul>
668** xLock() increases the lock. xUnlock() decreases the lock.
669** The xCheckReservedLock() method checks whether any database connection,
670** either in this process or in some other process, is holding a RESERVED,
671** PENDING, or EXCLUSIVE lock on the file.  It returns true
672** if such a lock exists and false otherwise.
673**
674** The xFileControl() method is a generic interface that allows custom
675** VFS implementations to directly control an open file using the
676** [sqlite3_file_control()] interface.  The second "op" argument is an
677** integer opcode.  The third argument is a generic pointer intended to
678** point to a structure that may contain arguments or space in which to
679** write return values.  Potential uses for xFileControl() might be
680** functions to enable blocking locks with timeouts, to change the
681** locking strategy (for example to use dot-file locks), to inquire
682** about the status of a lock, or to break stale locks.  The SQLite
683** core reserves all opcodes less than 100 for its own use.
684** A [file control opcodes | list of opcodes] less than 100 is available.
685** Applications that define a custom xFileControl method should use opcodes
686** greater than 100 to avoid conflicts.  VFS implementations should
687** return [SQLITE_NOTFOUND] for file control opcodes that they do not
688** recognize.
689**
690** The xSectorSize() method returns the sector size of the
691** device that underlies the file.  The sector size is the
692** minimum write that can be performed without disturbing
693** other bytes in the file.  The xDeviceCharacteristics()
694** method returns a bit vector describing behaviors of the
695** underlying device:
696**
697** <ul>
698** <li> [SQLITE_IOCAP_ATOMIC]
699** <li> [SQLITE_IOCAP_ATOMIC512]
700** <li> [SQLITE_IOCAP_ATOMIC1K]
701** <li> [SQLITE_IOCAP_ATOMIC2K]
702** <li> [SQLITE_IOCAP_ATOMIC4K]
703** <li> [SQLITE_IOCAP_ATOMIC8K]
704** <li> [SQLITE_IOCAP_ATOMIC16K]
705** <li> [SQLITE_IOCAP_ATOMIC32K]
706** <li> [SQLITE_IOCAP_ATOMIC64K]
707** <li> [SQLITE_IOCAP_SAFE_APPEND]
708** <li> [SQLITE_IOCAP_SEQUENTIAL]
709** </ul>
710**
711** The SQLITE_IOCAP_ATOMIC property means that all writes of
712** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
713** mean that writes of blocks that are nnn bytes in size and
714** are aligned to an address which is an integer multiple of
715** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
716** that when data is appended to a file, the data is appended
717** first then the size of the file is extended, never the other
718** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
719** information is written to disk in the same order as calls
720** to xWrite().
721**
722** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
723** in the unread portions of the buffer with zeros.  A VFS that
724** fails to zero-fill short reads might seem to work.  However,
725** failure to zero-fill short reads will eventually lead to
726** database corruption.
727*/
728typedef struct sqlite3_io_methods sqlite3_io_methods;
729struct sqlite3_io_methods {
730  int iVersion;
731  int (*xClose)(sqlite3_file*);
732  int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
733  int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
734  int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
735  int (*xSync)(sqlite3_file*, int flags);
736  int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
737  int (*xLock)(sqlite3_file*, int);
738  int (*xUnlock)(sqlite3_file*, int);
739  int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
740  int (*xFileControl)(sqlite3_file*, int op, void *pArg);
741  int (*xSectorSize)(sqlite3_file*);
742  int (*xDeviceCharacteristics)(sqlite3_file*);
743  /* Methods above are valid for version 1 */
744  int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
745  int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
746  void (*xShmBarrier)(sqlite3_file*);
747  int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
748  /* Methods above are valid for version 2 */
749  int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp);
750  int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p);
751  /* Methods above are valid for version 3 */
752  /* Additional methods may be added in future releases */
753};
754
755/*
756** CAPI3REF: Standard File Control Opcodes
757** KEYWORDS: {file control opcodes} {file control opcode}
758**
759** These integer constants are opcodes for the xFileControl method
760** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
761** interface.
762**
763** <ul>
764** <li>[[SQLITE_FCNTL_LOCKSTATE]]
765** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging.  This
766** opcode causes the xFileControl method to write the current state of
767** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
768** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
769** into an integer that the pArg argument points to. This capability
770** is used during testing and is only available when the SQLITE_TEST
771** compile-time option is used.
772**
773** <li>[[SQLITE_FCNTL_SIZE_HINT]]
774** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
775** layer a hint of how large the database file will grow to be during the
776** current transaction.  This hint is not guaranteed to be accurate but it
777** is often close.  The underlying VFS might choose to preallocate database
778** file space based on this hint in order to help writes to the database
779** file run faster.
780**
781** <li>[[SQLITE_FCNTL_CHUNK_SIZE]]
782** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
783** extends and truncates the database file in chunks of a size specified
784** by the user. The fourth argument to [sqlite3_file_control()] should
785** point to an integer (type int) containing the new chunk-size to use
786** for the nominated database. Allocating database file space in large
787** chunks (say 1MB at a time), may reduce file-system fragmentation and
788** improve performance on some systems.
789**
790** <li>[[SQLITE_FCNTL_FILE_POINTER]]
791** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
792** to the [sqlite3_file] object associated with a particular database
793** connection.  See the [sqlite3_file_control()] documentation for
794** additional information.
795**
796** <li>[[SQLITE_FCNTL_SYNC_OMITTED]]
797** No longer in use.
798**
799** <li>[[SQLITE_FCNTL_SYNC]]
800** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and
801** sent to the VFS immediately before the xSync method is invoked on a
802** database file descriptor. Or, if the xSync method is not invoked
803** because the user has configured SQLite with
804** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place
805** of the xSync method. In most cases, the pointer argument passed with
806** this file-control is NULL. However, if the database file is being synced
807** as part of a multi-database commit, the argument points to a nul-terminated
808** string containing the transactions master-journal file name. VFSes that
809** do not need this signal should silently ignore this opcode. Applications
810** should not call [sqlite3_file_control()] with this opcode as doing so may
811** disrupt the operation of the specialized VFSes that do require it.
812**
813** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]]
814** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite
815** and sent to the VFS after a transaction has been committed immediately
816** but before the database is unlocked. VFSes that do not need this signal
817** should silently ignore this opcode. Applications should not call
818** [sqlite3_file_control()] with this opcode as doing so may disrupt the
819** operation of the specialized VFSes that do require it.
820**
821** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]]
822** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
823** retry counts and intervals for certain disk I/O operations for the
824** windows [VFS] in order to provide robustness in the presence of
825** anti-virus programs.  By default, the windows VFS will retry file read,
826** file write, and file delete operations up to 10 times, with a delay
827** of 25 milliseconds before the first retry and with the delay increasing
828** by an additional 25 milliseconds with each subsequent retry.  This
829** opcode allows these two values (10 retries and 25 milliseconds of delay)
830** to be adjusted.  The values are changed for all database connections
831** within the same process.  The argument is a pointer to an array of two
832** integers where the first integer i the new retry count and the second
833** integer is the delay.  If either integer is negative, then the setting
834** is not changed but instead the prior value of that setting is written
835** into the array entry, allowing the current retry settings to be
836** interrogated.  The zDbName parameter is ignored.
837**
838** <li>[[SQLITE_FCNTL_PERSIST_WAL]]
839** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
840** persistent [WAL | Write Ahead Log] setting.  By default, the auxiliary
841** write ahead log and shared memory files used for transaction control
842** are automatically deleted when the latest connection to the database
843** closes.  Setting persistent WAL mode causes those files to persist after
844** close.  Persisting the files is useful when other processes that do not
845** have write permission on the directory containing the database file want
846** to read the database file, as the WAL and shared memory files must exist
847** in order for the database to be readable.  The fourth parameter to
848** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
849** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
850** WAL mode.  If the integer is -1, then it is overwritten with the current
851** WAL persistence setting.
852**
853** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]]
854** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
855** persistent "powersafe-overwrite" or "PSOW" setting.  The PSOW setting
856** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
857** xDeviceCharacteristics methods. The fourth parameter to
858** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
859** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
860** mode.  If the integer is -1, then it is overwritten with the current
861** zero-damage mode setting.
862**
863** <li>[[SQLITE_FCNTL_OVERWRITE]]
864** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
865** a write transaction to indicate that, unless it is rolled back for some
866** reason, the entire database file will be overwritten by the current
867** transaction. This is used by VACUUM operations.
868**
869** <li>[[SQLITE_FCNTL_VFSNAME]]
870** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
871** all [VFSes] in the VFS stack.  The names are of all VFS shims and the
872** final bottom-level VFS are written into memory obtained from
873** [sqlite3_malloc()] and the result is stored in the char* variable
874** that the fourth parameter of [sqlite3_file_control()] points to.
875** The caller is responsible for freeing the memory when done.  As with
876** all file-control actions, there is no guarantee that this will actually
877** do anything.  Callers should initialize the char* variable to a NULL
878** pointer in case this file-control is not implemented.  This file-control
879** is intended for diagnostic use only.
880**
881** <li>[[SQLITE_FCNTL_PRAGMA]]
882** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA]
883** file control is sent to the open [sqlite3_file] object corresponding
884** to the database file to which the pragma statement refers. ^The argument
885** to the [SQLITE_FCNTL_PRAGMA] file control is an array of
886** pointers to strings (char**) in which the second element of the array
887** is the name of the pragma and the third element is the argument to the
888** pragma or NULL if the pragma has no argument.  ^The handler for an
889** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element
890** of the char** argument point to a string obtained from [sqlite3_mprintf()]
891** or the equivalent and that string will become the result of the pragma or
892** the error message if the pragma fails. ^If the
893** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal
894** [PRAGMA] processing continues.  ^If the [SQLITE_FCNTL_PRAGMA]
895** file control returns [SQLITE_OK], then the parser assumes that the
896** VFS has handled the PRAGMA itself and the parser generates a no-op
897** prepared statement if result string is NULL, or that returns a copy
898** of the result string if the string is non-NULL.
899** ^If the [SQLITE_FCNTL_PRAGMA] file control returns
900** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means
901** that the VFS encountered an error while handling the [PRAGMA] and the
902** compilation of the PRAGMA fails with an error.  ^The [SQLITE_FCNTL_PRAGMA]
903** file control occurs at the beginning of pragma statement analysis and so
904** it is able to override built-in [PRAGMA] statements.
905**
906** <li>[[SQLITE_FCNTL_BUSYHANDLER]]
907** ^The [SQLITE_FCNTL_BUSYHANDLER]
908** file-control may be invoked by SQLite on the database file handle
909** shortly after it is opened in order to provide a custom VFS with access
910** to the connections busy-handler callback. The argument is of type (void **)
911** - an array of two (void *) values. The first (void *) actually points
912** to a function of type (int (*)(void *)). In order to invoke the connections
913** busy-handler, this function should be invoked with the second (void *) in
914** the array as the only argument. If it returns non-zero, then the operation
915** should be retried. If it returns zero, the custom VFS should abandon the
916** current operation.
917**
918** <li>[[SQLITE_FCNTL_TEMPFILENAME]]
919** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control
920** to have SQLite generate a
921** temporary filename using the same algorithm that is followed to generate
922** temporary filenames for TEMP tables and other internal uses.  The
923** argument should be a char** which will be filled with the filename
924** written into memory obtained from [sqlite3_malloc()].  The caller should
925** invoke [sqlite3_free()] on the result to avoid a memory leak.
926**
927** <li>[[SQLITE_FCNTL_MMAP_SIZE]]
928** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the
929** maximum number of bytes that will be used for memory-mapped I/O.
930** The argument is a pointer to a value of type sqlite3_int64 that
931** is an advisory maximum number of bytes in the file to memory map.  The
932** pointer is overwritten with the old value.  The limit is not changed if
933** the value originally pointed to is negative, and so the current limit
934** can be queried by passing in a pointer to a negative number.  This
935** file-control is used internally to implement [PRAGMA mmap_size].
936**
937** <li>[[SQLITE_FCNTL_TRACE]]
938** The [SQLITE_FCNTL_TRACE] file control provides advisory information
939** to the VFS about what the higher layers of the SQLite stack are doing.
940** This file control is used by some VFS activity tracing [shims].
941** The argument is a zero-terminated string.  Higher layers in the
942** SQLite stack may generate instances of this file control if
943** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled.
944**
945** <li>[[SQLITE_FCNTL_HAS_MOVED]]
946** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a
947** pointer to an integer and it writes a boolean into that integer depending
948** on whether or not the file has been renamed, moved, or deleted since it
949** was first opened.
950**
951** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]]
952** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging.  This
953** opcode causes the xFileControl method to swap the file handle with the one
954** pointed to by the pArg argument.  This capability is used during testing
955** and only needs to be supported when SQLITE_TEST is defined.
956**
957** <li>[[SQLITE_FCNTL_WAL_BLOCK]]
958** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might
959** be advantageous to block on the next WAL lock if the lock is not immediately
960** available.  The WAL subsystem issues this signal during rare
961** circumstances in order to fix a problem with priority inversion.
962** Applications should <em>not</em> use this file-control.
963**
964** </ul>
965*/
966#define SQLITE_FCNTL_LOCKSTATE               1
967#define SQLITE_FCNTL_GET_LOCKPROXYFILE       2
968#define SQLITE_FCNTL_SET_LOCKPROXYFILE       3
969#define SQLITE_FCNTL_LAST_ERRNO              4
970#define SQLITE_FCNTL_SIZE_HINT               5
971#define SQLITE_FCNTL_CHUNK_SIZE              6
972#define SQLITE_FCNTL_FILE_POINTER            7
973#define SQLITE_FCNTL_SYNC_OMITTED            8
974#define SQLITE_FCNTL_WIN32_AV_RETRY          9
975#define SQLITE_FCNTL_PERSIST_WAL            10
976#define SQLITE_FCNTL_OVERWRITE              11
977#define SQLITE_FCNTL_VFSNAME                12
978#define SQLITE_FCNTL_POWERSAFE_OVERWRITE    13
979#define SQLITE_FCNTL_PRAGMA                 14
980#define SQLITE_FCNTL_BUSYHANDLER            15
981#define SQLITE_FCNTL_TEMPFILENAME           16
982#define SQLITE_FCNTL_MMAP_SIZE              18
983#define SQLITE_FCNTL_TRACE                  19
984#define SQLITE_FCNTL_HAS_MOVED              20
985#define SQLITE_FCNTL_SYNC                   21
986#define SQLITE_FCNTL_COMMIT_PHASETWO        22
987#define SQLITE_FCNTL_WIN32_SET_HANDLE       23
988#define SQLITE_FCNTL_WAL_BLOCK              24
989
990/* deprecated names */
991#define SQLITE_GET_LOCKPROXYFILE      SQLITE_FCNTL_GET_LOCKPROXYFILE
992#define SQLITE_SET_LOCKPROXYFILE      SQLITE_FCNTL_SET_LOCKPROXYFILE
993#define SQLITE_LAST_ERRNO             SQLITE_FCNTL_LAST_ERRNO
994
995
996/*
997** CAPI3REF: Mutex Handle
998**
999** The mutex module within SQLite defines [sqlite3_mutex] to be an
1000** abstract type for a mutex object.  The SQLite core never looks
1001** at the internal representation of an [sqlite3_mutex].  It only
1002** deals with pointers to the [sqlite3_mutex] object.
1003**
1004** Mutexes are created using [sqlite3_mutex_alloc()].
1005*/
1006typedef struct sqlite3_mutex sqlite3_mutex;
1007
1008/*
1009** CAPI3REF: OS Interface Object
1010**
1011** An instance of the sqlite3_vfs object defines the interface between
1012** the SQLite core and the underlying operating system.  The "vfs"
1013** in the name of the object stands for "virtual file system".  See
1014** the [VFS | VFS documentation] for further information.
1015**
1016** The value of the iVersion field is initially 1 but may be larger in
1017** future versions of SQLite.  Additional fields may be appended to this
1018** object when the iVersion value is increased.  Note that the structure
1019** of the sqlite3_vfs object changes in the transaction between
1020** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not
1021** modified.
1022**
1023** The szOsFile field is the size of the subclassed [sqlite3_file]
1024** structure used by this VFS.  mxPathname is the maximum length of
1025** a pathname in this VFS.
1026**
1027** Registered sqlite3_vfs objects are kept on a linked list formed by
1028** the pNext pointer.  The [sqlite3_vfs_register()]
1029** and [sqlite3_vfs_unregister()] interfaces manage this list
1030** in a thread-safe way.  The [sqlite3_vfs_find()] interface
1031** searches the list.  Neither the application code nor the VFS
1032** implementation should use the pNext pointer.
1033**
1034** The pNext field is the only field in the sqlite3_vfs
1035** structure that SQLite will ever modify.  SQLite will only access
1036** or modify this field while holding a particular static mutex.
1037** The application should never modify anything within the sqlite3_vfs
1038** object once the object has been registered.
1039**
1040** The zName field holds the name of the VFS module.  The name must
1041** be unique across all VFS modules.
1042**
1043** [[sqlite3_vfs.xOpen]]
1044** ^SQLite guarantees that the zFilename parameter to xOpen
1045** is either a NULL pointer or string obtained
1046** from xFullPathname() with an optional suffix added.
1047** ^If a suffix is added to the zFilename parameter, it will
1048** consist of a single "-" character followed by no more than
1049** 11 alphanumeric and/or "-" characters.
1050** ^SQLite further guarantees that
1051** the string will be valid and unchanged until xClose() is
1052** called. Because of the previous sentence,
1053** the [sqlite3_file] can safely store a pointer to the
1054** filename if it needs to remember the filename for some reason.
1055** If the zFilename parameter to xOpen is a NULL pointer then xOpen
1056** must invent its own temporary name for the file.  ^Whenever the
1057** xFilename parameter is NULL it will also be the case that the
1058** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
1059**
1060** The flags argument to xOpen() includes all bits set in
1061** the flags argument to [sqlite3_open_v2()].  Or if [sqlite3_open()]
1062** or [sqlite3_open16()] is used, then flags includes at least
1063** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE].
1064** If xOpen() opens a file read-only then it sets *pOutFlags to
1065** include [SQLITE_OPEN_READONLY].  Other bits in *pOutFlags may be set.
1066**
1067** ^(SQLite will also add one of the following flags to the xOpen()
1068** call, depending on the object being opened:
1069**
1070** <ul>
1071** <li>  [SQLITE_OPEN_MAIN_DB]
1072** <li>  [SQLITE_OPEN_MAIN_JOURNAL]
1073** <li>  [SQLITE_OPEN_TEMP_DB]
1074** <li>  [SQLITE_OPEN_TEMP_JOURNAL]
1075** <li>  [SQLITE_OPEN_TRANSIENT_DB]
1076** <li>  [SQLITE_OPEN_SUBJOURNAL]
1077** <li>  [SQLITE_OPEN_MASTER_JOURNAL]
1078** <li>  [SQLITE_OPEN_WAL]
1079** </ul>)^
1080**
1081** The file I/O implementation can use the object type flags to
1082** change the way it deals with files.  For example, an application
1083** that does not care about crash recovery or rollback might make
1084** the open of a journal file a no-op.  Writes to this journal would
1085** also be no-ops, and any attempt to read the journal would return
1086** SQLITE_IOERR.  Or the implementation might recognize that a database
1087** file will be doing page-aligned sector reads and writes in a random
1088** order and set up its I/O subsystem accordingly.
1089**
1090** SQLite might also add one of the following flags to the xOpen method:
1091**
1092** <ul>
1093** <li> [SQLITE_OPEN_DELETEONCLOSE]
1094** <li> [SQLITE_OPEN_EXCLUSIVE]
1095** </ul>
1096**
1097** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
1098** deleted when it is closed.  ^The [SQLITE_OPEN_DELETEONCLOSE]
1099** will be set for TEMP databases and their journals, transient
1100** databases, and subjournals.
1101**
1102** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
1103** with the [SQLITE_OPEN_CREATE] flag, which are both directly
1104** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
1105** API.  The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
1106** SQLITE_OPEN_CREATE, is used to indicate that file should always
1107** be created, and that it is an error if it already exists.
1108** It is <i>not</i> used to indicate the file should be opened
1109** for exclusive access.
1110**
1111** ^At least szOsFile bytes of memory are allocated by SQLite
1112** to hold the  [sqlite3_file] structure passed as the third
1113** argument to xOpen.  The xOpen method does not have to
1114** allocate the structure; it should just fill it in.  Note that
1115** the xOpen method must set the sqlite3_file.pMethods to either
1116** a valid [sqlite3_io_methods] object or to NULL.  xOpen must do
1117** this even if the open fails.  SQLite expects that the sqlite3_file.pMethods
1118** element will be valid after xOpen returns regardless of the success
1119** or failure of the xOpen call.
1120**
1121** [[sqlite3_vfs.xAccess]]
1122** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
1123** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
1124** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
1125** to test whether a file is at least readable.   The file can be a
1126** directory.
1127**
1128** ^SQLite will always allocate at least mxPathname+1 bytes for the
1129** output buffer xFullPathname.  The exact size of the output buffer
1130** is also passed as a parameter to both  methods. If the output buffer
1131** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
1132** handled as a fatal error by SQLite, vfs implementations should endeavor
1133** to prevent this by setting mxPathname to a sufficiently large value.
1134**
1135** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
1136** interfaces are not strictly a part of the filesystem, but they are
1137** included in the VFS structure for completeness.
1138** The xRandomness() function attempts to return nBytes bytes
1139** of good-quality randomness into zOut.  The return value is
1140** the actual number of bytes of randomness obtained.
1141** The xSleep() method causes the calling thread to sleep for at
1142** least the number of microseconds given.  ^The xCurrentTime()
1143** method returns a Julian Day Number for the current date and time as
1144** a floating point value.
1145** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
1146** Day Number multiplied by 86400000 (the number of milliseconds in
1147** a 24-hour day).
1148** ^SQLite will use the xCurrentTimeInt64() method to get the current
1149** date and time if that method is available (if iVersion is 2 or
1150** greater and the function pointer is not NULL) and will fall back
1151** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
1152**
1153** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
1154** are not used by the SQLite core.  These optional interfaces are provided
1155** by some VFSes to facilitate testing of the VFS code. By overriding
1156** system calls with functions under its control, a test program can
1157** simulate faults and error conditions that would otherwise be difficult
1158** or impossible to induce.  The set of system calls that can be overridden
1159** varies from one VFS to another, and from one version of the same VFS to the
1160** next.  Applications that use these interfaces must be prepared for any
1161** or all of these interfaces to be NULL or for their behavior to change
1162** from one release to the next.  Applications must not attempt to access
1163** any of these methods if the iVersion of the VFS is less than 3.
1164*/
1165typedef struct sqlite3_vfs sqlite3_vfs;
1166typedef void (*sqlite3_syscall_ptr)(void);
1167struct sqlite3_vfs {
1168  int iVersion;            /* Structure version number (currently 3) */
1169  int szOsFile;            /* Size of subclassed sqlite3_file */
1170  int mxPathname;          /* Maximum file pathname length */
1171  sqlite3_vfs *pNext;      /* Next registered VFS */
1172  const char *zName;       /* Name of this virtual file system */
1173  void *pAppData;          /* Pointer to application-specific data */
1174  int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
1175               int flags, int *pOutFlags);
1176  int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
1177  int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
1178  int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
1179  void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
1180  void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
1181  void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
1182  void (*xDlClose)(sqlite3_vfs*, void*);
1183  int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
1184  int (*xSleep)(sqlite3_vfs*, int microseconds);
1185  int (*xCurrentTime)(sqlite3_vfs*, double*);
1186  int (*xGetLastError)(sqlite3_vfs*, int, char *);
1187  /*
1188  ** The methods above are in version 1 of the sqlite_vfs object
1189  ** definition.  Those that follow are added in version 2 or later
1190  */
1191  int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
1192  /*
1193  ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
1194  ** Those below are for version 3 and greater.
1195  */
1196  int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
1197  sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
1198  const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
1199  /*
1200  ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
1201  ** New fields may be appended in figure versions.  The iVersion
1202  ** value will increment whenever this happens.
1203  */
1204};
1205
1206/*
1207** CAPI3REF: Flags for the xAccess VFS method
1208**
1209** These integer constants can be used as the third parameter to
1210** the xAccess method of an [sqlite3_vfs] object.  They determine
1211** what kind of permissions the xAccess method is looking for.
1212** With SQLITE_ACCESS_EXISTS, the xAccess method
1213** simply checks whether the file exists.
1214** With SQLITE_ACCESS_READWRITE, the xAccess method
1215** checks whether the named directory is both readable and writable
1216** (in other words, if files can be added, removed, and renamed within
1217** the directory).
1218** The SQLITE_ACCESS_READWRITE constant is currently used only by the
1219** [temp_store_directory pragma], though this could change in a future
1220** release of SQLite.
1221** With SQLITE_ACCESS_READ, the xAccess method
1222** checks whether the file is readable.  The SQLITE_ACCESS_READ constant is
1223** currently unused, though it might be used in a future release of
1224** SQLite.
1225*/
1226#define SQLITE_ACCESS_EXISTS    0
1227#define SQLITE_ACCESS_READWRITE 1   /* Used by PRAGMA temp_store_directory */
1228#define SQLITE_ACCESS_READ      2   /* Unused */
1229
1230/*
1231** CAPI3REF: Flags for the xShmLock VFS method
1232**
1233** These integer constants define the various locking operations
1234** allowed by the xShmLock method of [sqlite3_io_methods].  The
1235** following are the only legal combinations of flags to the
1236** xShmLock method:
1237**
1238** <ul>
1239** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
1240** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
1241** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
1242** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
1243** </ul>
1244**
1245** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
1246** was given on the corresponding lock.
1247**
1248** The xShmLock method can transition between unlocked and SHARED or
1249** between unlocked and EXCLUSIVE.  It cannot transition between SHARED
1250** and EXCLUSIVE.
1251*/
1252#define SQLITE_SHM_UNLOCK       1
1253#define SQLITE_SHM_LOCK         2
1254#define SQLITE_SHM_SHARED       4
1255#define SQLITE_SHM_EXCLUSIVE    8
1256
1257/*
1258** CAPI3REF: Maximum xShmLock index
1259**
1260** The xShmLock method on [sqlite3_io_methods] may use values
1261** between 0 and this upper bound as its "offset" argument.
1262** The SQLite core will never attempt to acquire or release a
1263** lock outside of this range
1264*/
1265#define SQLITE_SHM_NLOCK        8
1266
1267
1268/*
1269** CAPI3REF: Initialize The SQLite Library
1270**
1271** ^The sqlite3_initialize() routine initializes the
1272** SQLite library.  ^The sqlite3_shutdown() routine
1273** deallocates any resources that were allocated by sqlite3_initialize().
1274** These routines are designed to aid in process initialization and
1275** shutdown on embedded systems.  Workstation applications using
1276** SQLite normally do not need to invoke either of these routines.
1277**
1278** A call to sqlite3_initialize() is an "effective" call if it is
1279** the first time sqlite3_initialize() is invoked during the lifetime of
1280** the process, or if it is the first time sqlite3_initialize() is invoked
1281** following a call to sqlite3_shutdown().  ^(Only an effective call
1282** of sqlite3_initialize() does any initialization.  All other calls
1283** are harmless no-ops.)^
1284**
1285** A call to sqlite3_shutdown() is an "effective" call if it is the first
1286** call to sqlite3_shutdown() since the last sqlite3_initialize().  ^(Only
1287** an effective call to sqlite3_shutdown() does any deinitialization.
1288** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
1289**
1290** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
1291** is not.  The sqlite3_shutdown() interface must only be called from a
1292** single thread.  All open [database connections] must be closed and all
1293** other SQLite resources must be deallocated prior to invoking
1294** sqlite3_shutdown().
1295**
1296** Among other things, ^sqlite3_initialize() will invoke
1297** sqlite3_os_init().  Similarly, ^sqlite3_shutdown()
1298** will invoke sqlite3_os_end().
1299**
1300** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
1301** ^If for some reason, sqlite3_initialize() is unable to initialize
1302** the library (perhaps it is unable to allocate a needed resource such
1303** as a mutex) it returns an [error code] other than [SQLITE_OK].
1304**
1305** ^The sqlite3_initialize() routine is called internally by many other
1306** SQLite interfaces so that an application usually does not need to
1307** invoke sqlite3_initialize() directly.  For example, [sqlite3_open()]
1308** calls sqlite3_initialize() so the SQLite library will be automatically
1309** initialized when [sqlite3_open()] is called if it has not be initialized
1310** already.  ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
1311** compile-time option, then the automatic calls to sqlite3_initialize()
1312** are omitted and the application must call sqlite3_initialize() directly
1313** prior to using any other SQLite interface.  For maximum portability,
1314** it is recommended that applications always invoke sqlite3_initialize()
1315** directly prior to using any other SQLite interface.  Future releases
1316** of SQLite may require this.  In other words, the behavior exhibited
1317** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
1318** default behavior in some future release of SQLite.
1319**
1320** The sqlite3_os_init() routine does operating-system specific
1321** initialization of the SQLite library.  The sqlite3_os_end()
1322** routine undoes the effect of sqlite3_os_init().  Typical tasks
1323** performed by these routines include allocation or deallocation
1324** of static resources, initialization of global variables,
1325** setting up a default [sqlite3_vfs] module, or setting up
1326** a default configuration using [sqlite3_config()].
1327**
1328** The application should never invoke either sqlite3_os_init()
1329** or sqlite3_os_end() directly.  The application should only invoke
1330** sqlite3_initialize() and sqlite3_shutdown().  The sqlite3_os_init()
1331** interface is called automatically by sqlite3_initialize() and
1332** sqlite3_os_end() is called by sqlite3_shutdown().  Appropriate
1333** implementations for sqlite3_os_init() and sqlite3_os_end()
1334** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
1335** When [custom builds | built for other platforms]
1336** (using the [SQLITE_OS_OTHER=1] compile-time
1337** option) the application must supply a suitable implementation for
1338** sqlite3_os_init() and sqlite3_os_end().  An application-supplied
1339** implementation of sqlite3_os_init() or sqlite3_os_end()
1340** must return [SQLITE_OK] on success and some other [error code] upon
1341** failure.
1342*/
1343SQLITE_API int SQLITE_STDCALL sqlite3_initialize(void);
1344SQLITE_API int SQLITE_STDCALL sqlite3_shutdown(void);
1345SQLITE_API int SQLITE_STDCALL sqlite3_os_init(void);
1346SQLITE_API int SQLITE_STDCALL sqlite3_os_end(void);
1347
1348/*
1349** CAPI3REF: Configuring The SQLite Library
1350**
1351** The sqlite3_config() interface is used to make global configuration
1352** changes to SQLite in order to tune SQLite to the specific needs of
1353** the application.  The default configuration is recommended for most
1354** applications and so this routine is usually not necessary.  It is
1355** provided to support rare applications with unusual needs.
1356**
1357** The sqlite3_config() interface is not threadsafe.  The application
1358** must insure that no other SQLite interfaces are invoked by other
1359** threads while sqlite3_config() is running.  Furthermore, sqlite3_config()
1360** may only be invoked prior to library initialization using
1361** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
1362** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
1363** [sqlite3_shutdown()] then it will return SQLITE_MISUSE.
1364** Note, however, that ^sqlite3_config() can be called as part of the
1365** implementation of an application-defined [sqlite3_os_init()].
1366**
1367** The first argument to sqlite3_config() is an integer
1368** [configuration option] that determines
1369** what property of SQLite is to be configured.  Subsequent arguments
1370** vary depending on the [configuration option]
1371** in the first argument.
1372**
1373** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
1374** ^If the option is unknown or SQLite is unable to set the option
1375** then this routine returns a non-zero [error code].
1376*/
1377SQLITE_API int SQLITE_CDECL sqlite3_config(int, ...);
1378
1379/*
1380** CAPI3REF: Configure database connections
1381**
1382** The sqlite3_db_config() interface is used to make configuration
1383** changes to a [database connection].  The interface is similar to
1384** [sqlite3_config()] except that the changes apply to a single
1385** [database connection] (specified in the first argument).
1386**
1387** The second argument to sqlite3_db_config(D,V,...)  is the
1388** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code
1389** that indicates what aspect of the [database connection] is being configured.
1390** Subsequent arguments vary depending on the configuration verb.
1391**
1392** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
1393** the call is considered successful.
1394*/
1395SQLITE_API int SQLITE_CDECL sqlite3_db_config(sqlite3*, int op, ...);
1396
1397/*
1398** CAPI3REF: Memory Allocation Routines
1399**
1400** An instance of this object defines the interface between SQLite
1401** and low-level memory allocation routines.
1402**
1403** This object is used in only one place in the SQLite interface.
1404** A pointer to an instance of this object is the argument to
1405** [sqlite3_config()] when the configuration option is
1406** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].
1407** By creating an instance of this object
1408** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
1409** during configuration, an application can specify an alternative
1410** memory allocation subsystem for SQLite to use for all of its
1411** dynamic memory needs.
1412**
1413** Note that SQLite comes with several [built-in memory allocators]
1414** that are perfectly adequate for the overwhelming majority of applications
1415** and that this object is only useful to a tiny minority of applications
1416** with specialized memory allocation requirements.  This object is
1417** also used during testing of SQLite in order to specify an alternative
1418** memory allocator that simulates memory out-of-memory conditions in
1419** order to verify that SQLite recovers gracefully from such
1420** conditions.
1421**
1422** The xMalloc, xRealloc, and xFree methods must work like the
1423** malloc(), realloc() and free() functions from the standard C library.
1424** ^SQLite guarantees that the second argument to
1425** xRealloc is always a value returned by a prior call to xRoundup.
1426**
1427** xSize should return the allocated size of a memory allocation
1428** previously obtained from xMalloc or xRealloc.  The allocated size
1429** is always at least as big as the requested size but may be larger.
1430**
1431** The xRoundup method returns what would be the allocated size of
1432** a memory allocation given a particular requested size.  Most memory
1433** allocators round up memory allocations at least to the next multiple
1434** of 8.  Some allocators round up to a larger multiple or to a power of 2.
1435** Every memory allocation request coming in through [sqlite3_malloc()]
1436** or [sqlite3_realloc()] first calls xRoundup.  If xRoundup returns 0,
1437** that causes the corresponding memory allocation to fail.
1438**
1439** The xInit method initializes the memory allocator.  For example,
1440** it might allocate any require mutexes or initialize internal data
1441** structures.  The xShutdown method is invoked (indirectly) by
1442** [sqlite3_shutdown()] and should deallocate any resources acquired
1443** by xInit.  The pAppData pointer is used as the only parameter to
1444** xInit and xShutdown.
1445**
1446** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes
1447** the xInit method, so the xInit method need not be threadsafe.  The
1448** xShutdown method is only called from [sqlite3_shutdown()] so it does
1449** not need to be threadsafe either.  For all other methods, SQLite
1450** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
1451** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
1452** it is by default) and so the methods are automatically serialized.
1453** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
1454** methods must be threadsafe or else make their own arrangements for
1455** serialization.
1456**
1457** SQLite will never invoke xInit() more than once without an intervening
1458** call to xShutdown().
1459*/
1460typedef struct sqlite3_mem_methods sqlite3_mem_methods;
1461struct sqlite3_mem_methods {
1462  void *(*xMalloc)(int);         /* Memory allocation function */
1463  void (*xFree)(void*);          /* Free a prior allocation */
1464  void *(*xRealloc)(void*,int);  /* Resize an allocation */
1465  int (*xSize)(void*);           /* Return the size of an allocation */
1466  int (*xRoundup)(int);          /* Round up request size to allocation size */
1467  int (*xInit)(void*);           /* Initialize the memory allocator */
1468  void (*xShutdown)(void*);      /* Deinitialize the memory allocator */
1469  void *pAppData;                /* Argument to xInit() and xShutdown() */
1470};
1471
1472/*
1473** CAPI3REF: Configuration Options
1474** KEYWORDS: {configuration option}
1475**
1476** These constants are the available integer configuration options that
1477** can be passed as the first argument to the [sqlite3_config()] interface.
1478**
1479** New configuration options may be added in future releases of SQLite.
1480** Existing configuration options might be discontinued.  Applications
1481** should check the return code from [sqlite3_config()] to make sure that
1482** the call worked.  The [sqlite3_config()] interface will return a
1483** non-zero [error code] if a discontinued or unsupported configuration option
1484** is invoked.
1485**
1486** <dl>
1487** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
1488** <dd>There are no arguments to this option.  ^This option sets the
1489** [threading mode] to Single-thread.  In other words, it disables
1490** all mutexing and puts SQLite into a mode where it can only be used
1491** by a single thread.   ^If SQLite is compiled with
1492** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1493** it is not possible to change the [threading mode] from its default
1494** value of Single-thread and so [sqlite3_config()] will return
1495** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
1496** configuration option.</dd>
1497**
1498** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt>
1499** <dd>There are no arguments to this option.  ^This option sets the
1500** [threading mode] to Multi-thread.  In other words, it disables
1501** mutexing on [database connection] and [prepared statement] objects.
1502** The application is responsible for serializing access to
1503** [database connections] and [prepared statements].  But other mutexes
1504** are enabled so that SQLite will be safe to use in a multi-threaded
1505** environment as long as no two threads attempt to use the same
1506** [database connection] at the same time.  ^If SQLite is compiled with
1507** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1508** it is not possible to set the Multi-thread [threading mode] and
1509** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1510** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
1511**
1512** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt>
1513** <dd>There are no arguments to this option.  ^This option sets the
1514** [threading mode] to Serialized. In other words, this option enables
1515** all mutexes including the recursive
1516** mutexes on [database connection] and [prepared statement] objects.
1517** In this mode (which is the default when SQLite is compiled with
1518** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
1519** to [database connections] and [prepared statements] so that the
1520** application is free to use the same [database connection] or the
1521** same [prepared statement] in different threads at the same time.
1522** ^If SQLite is compiled with
1523** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1524** it is not possible to set the Serialized [threading mode] and
1525** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1526** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
1527**
1528** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt>
1529** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is
1530** a pointer to an instance of the [sqlite3_mem_methods] structure.
1531** The argument specifies
1532** alternative low-level memory allocation routines to be used in place of
1533** the memory allocation routines built into SQLite.)^ ^SQLite makes
1534** its own private copy of the content of the [sqlite3_mem_methods] structure
1535** before the [sqlite3_config()] call returns.</dd>
1536**
1537** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt>
1538** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which
1539** is a pointer to an instance of the [sqlite3_mem_methods] structure.
1540** The [sqlite3_mem_methods]
1541** structure is filled with the currently defined memory allocation routines.)^
1542** This option can be used to overload the default memory allocation
1543** routines with a wrapper that simulations memory allocation failure or
1544** tracks memory usage, for example. </dd>
1545**
1546** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt>
1547** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int,
1548** interpreted as a boolean, which enables or disables the collection of
1549** memory allocation statistics. ^(When memory allocation statistics are
1550** disabled, the following SQLite interfaces become non-operational:
1551**   <ul>
1552**   <li> [sqlite3_memory_used()]
1553**   <li> [sqlite3_memory_highwater()]
1554**   <li> [sqlite3_soft_heap_limit64()]
1555**   <li> [sqlite3_status64()]
1556**   </ul>)^
1557** ^Memory allocation statistics are enabled by default unless SQLite is
1558** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
1559** allocation statistics are disabled by default.
1560** </dd>
1561**
1562** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt>
1563** <dd> ^The SQLITE_CONFIG_SCRATCH option specifies a static memory buffer
1564** that SQLite can use for scratch memory.  ^(There are three arguments
1565** to SQLITE_CONFIG_SCRATCH:  A pointer an 8-byte
1566** aligned memory buffer from which the scratch allocations will be
1567** drawn, the size of each scratch allocation (sz),
1568** and the maximum number of scratch allocations (N).)^
1569** The first argument must be a pointer to an 8-byte aligned buffer
1570** of at least sz*N bytes of memory.
1571** ^SQLite will not use more than one scratch buffers per thread.
1572** ^SQLite will never request a scratch buffer that is more than 6
1573** times the database page size.
1574** ^If SQLite needs needs additional
1575** scratch memory beyond what is provided by this configuration option, then
1576** [sqlite3_malloc()] will be used to obtain the memory needed.<p>
1577** ^When the application provides any amount of scratch memory using
1578** SQLITE_CONFIG_SCRATCH, SQLite avoids unnecessary large
1579** [sqlite3_malloc|heap allocations].
1580** This can help [Robson proof|prevent memory allocation failures] due to heap
1581** fragmentation in low-memory embedded systems.
1582** </dd>
1583**
1584** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>
1585** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a static memory buffer
1586** that SQLite can use for the database page cache with the default page
1587** cache implementation.
1588** This configuration should not be used if an application-define page
1589** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2]
1590** configuration option.
1591** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to
1592** 8-byte aligned
1593** memory, the size of each page buffer (sz), and the number of pages (N).
1594** The sz argument should be the size of the largest database page
1595** (a power of two between 512 and 65536) plus some extra bytes for each
1596** page header.  ^The number of extra bytes needed by the page header
1597** can be determined using the [SQLITE_CONFIG_PCACHE_HDRSZ] option
1598** to [sqlite3_config()].
1599** ^It is harmless, apart from the wasted memory,
1600** for the sz parameter to be larger than necessary.  The first
1601** argument should pointer to an 8-byte aligned block of memory that
1602** is at least sz*N bytes of memory, otherwise subsequent behavior is
1603** undefined.
1604** ^SQLite will use the memory provided by the first argument to satisfy its
1605** memory needs for the first N pages that it adds to cache.  ^If additional
1606** page cache memory is needed beyond what is provided by this option, then
1607** SQLite goes to [sqlite3_malloc()] for the additional storage space.</dd>
1608**
1609** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt>
1610** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer
1611** that SQLite will use for all of its dynamic memory allocation needs
1612** beyond those provided for by [SQLITE_CONFIG_SCRATCH] and
1613** [SQLITE_CONFIG_PAGECACHE].
1614** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled
1615** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns
1616** [SQLITE_ERROR] if invoked otherwise.
1617** ^There are three arguments to SQLITE_CONFIG_HEAP:
1618** An 8-byte aligned pointer to the memory,
1619** the number of bytes in the memory buffer, and the minimum allocation size.
1620** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
1621** to using its default memory allocator (the system malloc() implementation),
1622** undoing any prior invocation of [SQLITE_CONFIG_MALLOC].  ^If the
1623** memory pointer is not NULL then the alternative memory
1624** allocator is engaged to handle all of SQLites memory allocation needs.
1625** The first pointer (the memory pointer) must be aligned to an 8-byte
1626** boundary or subsequent behavior of SQLite will be undefined.
1627** The minimum allocation size is capped at 2**12. Reasonable values
1628** for the minimum allocation size are 2**5 through 2**8.</dd>
1629**
1630** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt>
1631** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a
1632** pointer to an instance of the [sqlite3_mutex_methods] structure.
1633** The argument specifies alternative low-level mutex routines to be used
1634** in place the mutex routines built into SQLite.)^  ^SQLite makes a copy of
1635** the content of the [sqlite3_mutex_methods] structure before the call to
1636** [sqlite3_config()] returns. ^If SQLite is compiled with
1637** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1638** the entire mutexing subsystem is omitted from the build and hence calls to
1639** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
1640** return [SQLITE_ERROR].</dd>
1641**
1642** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt>
1643** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which
1644** is a pointer to an instance of the [sqlite3_mutex_methods] structure.  The
1645** [sqlite3_mutex_methods]
1646** structure is filled with the currently defined mutex routines.)^
1647** This option can be used to overload the default mutex allocation
1648** routines with a wrapper used to track mutex usage for performance
1649** profiling or testing, for example.   ^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_GETMUTEX configuration option will
1653** return [SQLITE_ERROR].</dd>
1654**
1655** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt>
1656** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine
1657** the default size of lookaside memory on each [database connection].
1658** The first argument is the
1659** size of each lookaside buffer slot and the second is the number of
1660** slots allocated to each database connection.)^  ^(SQLITE_CONFIG_LOOKASIDE
1661** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
1662** option to [sqlite3_db_config()] can be used to change the lookaside
1663** configuration on individual connections.)^ </dd>
1664**
1665** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt>
1666** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is
1667** a pointer to an [sqlite3_pcache_methods2] object.  This object specifies
1668** the interface to a custom page cache implementation.)^
1669** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd>
1670**
1671** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt>
1672** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which
1673** is a pointer to an [sqlite3_pcache_methods2] object.  SQLite copies of
1674** the current page cache implementation into that object.)^ </dd>
1675**
1676** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>
1677** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite
1678** global [error log].
1679** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
1680** function with a call signature of void(*)(void*,int,const char*),
1681** and a pointer to void. ^If the function pointer is not NULL, it is
1682** invoked by [sqlite3_log()] to process each logging event.  ^If the
1683** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
1684** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
1685** passed through as the first parameter to the application-defined logger
1686** function whenever that function is invoked.  ^The second parameter to
1687** the logger function is a copy of the first parameter to the corresponding
1688** [sqlite3_log()] call and is intended to be a [result code] or an
1689** [extended result code].  ^The third parameter passed to the logger is
1690** log message after formatting via [sqlite3_snprintf()].
1691** The SQLite logging interface is not reentrant; the logger function
1692** supplied by the application must not invoke any SQLite interface.
1693** In a multi-threaded application, the application-defined logger
1694** function must be threadsafe. </dd>
1695**
1696** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI
1697** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int.
1698** If non-zero, then URI handling is globally enabled. If the parameter is zero,
1699** then URI handling is globally disabled.)^ ^If URI handling is globally
1700** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()],
1701** [sqlite3_open16()] or
1702** specified as part of [ATTACH] commands are interpreted as URIs, regardless
1703** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
1704** connection is opened. ^If it is globally disabled, filenames are
1705** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
1706** database connection is opened. ^(By default, URI handling is globally
1707** disabled. The default value may be changed by compiling with the
1708** [SQLITE_USE_URI] symbol defined.)^
1709**
1710** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN
1711** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer
1712** argument which is interpreted as a boolean in order to enable or disable
1713** the use of covering indices for full table scans in the query optimizer.
1714** ^The default setting is determined
1715** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on"
1716** if that compile-time option is omitted.
1717** The ability to disable the use of covering indices for full table scans
1718** is because some incorrectly coded legacy applications might malfunction
1719** when the optimization is enabled.  Providing the ability to
1720** disable the optimization allows the older, buggy application code to work
1721** without change even with newer versions of SQLite.
1722**
1723** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]]
1724** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE
1725** <dd> These options are obsolete and should not be used by new code.
1726** They are retained for backwards compatibility but are now no-ops.
1727** </dd>
1728**
1729** [[SQLITE_CONFIG_SQLLOG]]
1730** <dt>SQLITE_CONFIG_SQLLOG
1731** <dd>This option is only available if sqlite is compiled with the
1732** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should
1733** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int).
1734** The second should be of type (void*). The callback is invoked by the library
1735** in three separate circumstances, identified by the value passed as the
1736** fourth parameter. If the fourth parameter is 0, then the database connection
1737** passed as the second argument has just been opened. The third argument
1738** points to a buffer containing the name of the main database file. If the
1739** fourth parameter is 1, then the SQL statement that the third parameter
1740** points to has just been executed. Or, if the fourth parameter is 2, then
1741** the connection being passed as the second parameter is being closed. The
1742** third parameter is passed NULL In this case.  An example of using this
1743** configuration option can be seen in the "test_sqllog.c" source file in
1744** the canonical SQLite source tree.</dd>
1745**
1746** [[SQLITE_CONFIG_MMAP_SIZE]]
1747** <dt>SQLITE_CONFIG_MMAP_SIZE
1748** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values
1749** that are the default mmap size limit (the default setting for
1750** [PRAGMA mmap_size]) and the maximum allowed mmap size limit.
1751** ^The default setting can be overridden by each database connection using
1752** either the [PRAGMA mmap_size] command, or by using the
1753** [SQLITE_FCNTL_MMAP_SIZE] file control.  ^(The maximum allowed mmap size
1754** will be silently truncated if necessary so that it does not exceed the
1755** compile-time maximum mmap size set by the
1756** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^
1757** ^If either argument to this option is negative, then that argument is
1758** changed to its compile-time default.
1759**
1760** [[SQLITE_CONFIG_WIN32_HEAPSIZE]]
1761** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE
1762** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is
1763** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro
1764** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value
1765** that specifies the maximum size of the created heap.
1766**
1767** [[SQLITE_CONFIG_PCACHE_HDRSZ]]
1768** <dt>SQLITE_CONFIG_PCACHE_HDRSZ
1769** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which
1770** is a pointer to an integer and writes into that integer the number of extra
1771** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE].
1772** The amount of extra space required can change depending on the compiler,
1773** target platform, and SQLite version.
1774**
1775** [[SQLITE_CONFIG_PMASZ]]
1776** <dt>SQLITE_CONFIG_PMASZ
1777** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which
1778** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded
1779** sorter to that integer.  The default minimum PMA Size is set by the
1780** [SQLITE_SORTER_PMASZ] compile-time option.  New threads are launched
1781** to help with sort operations when multithreaded sorting
1782** is enabled (using the [PRAGMA threads] command) and the amount of content
1783** to be sorted exceeds the page size times the minimum of the
1784** [PRAGMA cache_size] setting and this value.
1785** </dl>
1786*/
1787#define SQLITE_CONFIG_SINGLETHREAD  1  /* nil */
1788#define SQLITE_CONFIG_MULTITHREAD   2  /* nil */
1789#define SQLITE_CONFIG_SERIALIZED    3  /* nil */
1790#define SQLITE_CONFIG_MALLOC        4  /* sqlite3_mem_methods* */
1791#define SQLITE_CONFIG_GETMALLOC     5  /* sqlite3_mem_methods* */
1792#define SQLITE_CONFIG_SCRATCH       6  /* void*, int sz, int N */
1793#define SQLITE_CONFIG_PAGECACHE     7  /* void*, int sz, int N */
1794#define SQLITE_CONFIG_HEAP          8  /* void*, int nByte, int min */
1795#define SQLITE_CONFIG_MEMSTATUS     9  /* boolean */
1796#define SQLITE_CONFIG_MUTEX        10  /* sqlite3_mutex_methods* */
1797#define SQLITE_CONFIG_GETMUTEX     11  /* sqlite3_mutex_methods* */
1798/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */
1799#define SQLITE_CONFIG_LOOKASIDE    13  /* int int */
1800#define SQLITE_CONFIG_PCACHE       14  /* no-op */
1801#define SQLITE_CONFIG_GETPCACHE    15  /* no-op */
1802#define SQLITE_CONFIG_LOG          16  /* xFunc, void* */
1803#define SQLITE_CONFIG_URI          17  /* int */
1804#define SQLITE_CONFIG_PCACHE2      18  /* sqlite3_pcache_methods2* */
1805#define SQLITE_CONFIG_GETPCACHE2   19  /* sqlite3_pcache_methods2* */
1806#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20  /* int */
1807#define SQLITE_CONFIG_SQLLOG       21  /* xSqllog, void* */
1808#define SQLITE_CONFIG_MMAP_SIZE    22  /* sqlite3_int64, sqlite3_int64 */
1809#define SQLITE_CONFIG_WIN32_HEAPSIZE      23  /* int nByte */
1810#define SQLITE_CONFIG_PCACHE_HDRSZ        24  /* int *psz */
1811#define SQLITE_CONFIG_PMASZ               25  /* unsigned int szPma */
1812
1813/*
1814** CAPI3REF: Database Connection Configuration Options
1815**
1816** These constants are the available integer configuration options that
1817** can be passed as the second argument to the [sqlite3_db_config()] interface.
1818**
1819** New configuration options may be added in future releases of SQLite.
1820** Existing configuration options might be discontinued.  Applications
1821** should check the return code from [sqlite3_db_config()] to make sure that
1822** the call worked.  ^The [sqlite3_db_config()] interface will return a
1823** non-zero [error code] if a discontinued or unsupported configuration option
1824** is invoked.
1825**
1826** <dl>
1827** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
1828** <dd> ^This option takes three additional arguments that determine the
1829** [lookaside memory allocator] configuration for the [database connection].
1830** ^The first argument (the third parameter to [sqlite3_db_config()] is a
1831** pointer to a memory buffer to use for lookaside memory.
1832** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
1833** may be NULL in which case SQLite will allocate the
1834** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
1835** size of each lookaside buffer slot.  ^The third argument is the number of
1836** slots.  The size of the buffer in the first argument must be greater than
1837** or equal to the product of the second and third arguments.  The buffer
1838** must be aligned to an 8-byte boundary.  ^If the second argument to
1839** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
1840** rounded down to the next smaller multiple of 8.  ^(The lookaside memory
1841** configuration for a database connection can only be changed when that
1842** connection is not currently using lookaside memory, or in other words
1843** when the "current value" returned by
1844** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero.
1845** Any attempt to change the lookaside memory configuration when lookaside
1846** memory is in use leaves the configuration unchanged and returns
1847** [SQLITE_BUSY].)^</dd>
1848**
1849** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
1850** <dd> ^This option is used to enable or disable the enforcement of
1851** [foreign key constraints].  There should be two additional arguments.
1852** The first argument is an integer which is 0 to disable FK enforcement,
1853** positive to enable FK enforcement or negative to leave FK enforcement
1854** unchanged.  The second parameter is a pointer to an integer into which
1855** is written 0 or 1 to indicate whether FK enforcement is off or on
1856** following this call.  The second parameter may be a NULL pointer, in
1857** which case the FK enforcement setting is not reported back. </dd>
1858**
1859** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
1860** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
1861** There should be two additional arguments.
1862** The first argument is an integer which is 0 to disable triggers,
1863** positive to enable triggers or negative to leave the setting unchanged.
1864** The second parameter is a pointer to an integer into which
1865** is written 0 or 1 to indicate whether triggers are disabled or enabled
1866** following this call.  The second parameter may be a NULL pointer, in
1867** which case the trigger setting is not reported back. </dd>
1868**
1869** </dl>
1870*/
1871#define SQLITE_DBCONFIG_LOOKASIDE       1001  /* void* int int */
1872#define SQLITE_DBCONFIG_ENABLE_FKEY     1002  /* int int* */
1873#define SQLITE_DBCONFIG_ENABLE_TRIGGER  1003  /* int int* */
1874
1875
1876/*
1877** CAPI3REF: Enable Or Disable Extended Result Codes
1878**
1879** ^The sqlite3_extended_result_codes() routine enables or disables the
1880** [extended result codes] feature of SQLite. ^The extended result
1881** codes are disabled by default for historical compatibility.
1882*/
1883SQLITE_API int SQLITE_STDCALL sqlite3_extended_result_codes(sqlite3*, int onoff);
1884
1885/*
1886** CAPI3REF: Last Insert Rowid
1887**
1888** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables)
1889** has a unique 64-bit signed
1890** integer key called the [ROWID | "rowid"]. ^The rowid is always available
1891** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
1892** names are not also used by explicitly declared columns. ^If
1893** the table has a column of type [INTEGER PRIMARY KEY] then that column
1894** is another alias for the rowid.
1895**
1896** ^The sqlite3_last_insert_rowid(D) interface returns the [rowid] of the
1897** most recent successful [INSERT] into a rowid table or [virtual table]
1898** on database connection D.
1899** ^Inserts into [WITHOUT ROWID] tables are not recorded.
1900** ^If no successful [INSERT]s into rowid tables
1901** have ever occurred on the database connection D,
1902** then sqlite3_last_insert_rowid(D) returns zero.
1903**
1904** ^(If an [INSERT] occurs within a trigger or within a [virtual table]
1905** method, then this routine will return the [rowid] of the inserted
1906** row as long as the trigger or virtual table method is running.
1907** But once the trigger or virtual table method ends, the value returned
1908** by this routine reverts to what it was before the trigger or virtual
1909** table method began.)^
1910**
1911** ^An [INSERT] that fails due to a constraint violation is not a
1912** successful [INSERT] and does not change the value returned by this
1913** routine.  ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
1914** and INSERT OR ABORT make no changes to the return value of this
1915** routine when their insertion fails.  ^(When INSERT OR REPLACE
1916** encounters a constraint violation, it does not fail.  The
1917** INSERT continues to completion after deleting rows that caused
1918** the constraint problem so INSERT OR REPLACE will always change
1919** the return value of this interface.)^
1920**
1921** ^For the purposes of this routine, an [INSERT] is considered to
1922** be successful even if it is subsequently rolled back.
1923**
1924** This function is accessible to SQL statements via the
1925** [last_insert_rowid() SQL function].
1926**
1927** If a separate thread performs a new [INSERT] on the same
1928** database connection while the [sqlite3_last_insert_rowid()]
1929** function is running and thus changes the last insert [rowid],
1930** then the value returned by [sqlite3_last_insert_rowid()] is
1931** unpredictable and might not equal either the old or the new
1932** last insert [rowid].
1933*/
1934SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_last_insert_rowid(sqlite3*);
1935
1936/*
1937** CAPI3REF: Count The Number Of Rows Modified
1938**
1939** ^This function returns the number of rows modified, inserted or
1940** deleted by the most recently completed INSERT, UPDATE or DELETE
1941** statement on the database connection specified by the only parameter.
1942** ^Executing any other type of SQL statement does not modify the value
1943** returned by this function.
1944**
1945** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are
1946** considered - auxiliary changes caused by [CREATE TRIGGER | triggers],
1947** [foreign key actions] or [REPLACE] constraint resolution are not counted.
1948**
1949** Changes to a view that are intercepted by
1950** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value
1951** returned by sqlite3_changes() immediately after an INSERT, UPDATE or
1952** DELETE statement run on a view is always zero. Only changes made to real
1953** tables are counted.
1954**
1955** Things are more complicated if the sqlite3_changes() function is
1956** executed while a trigger program is running. This may happen if the
1957** program uses the [changes() SQL function], or if some other callback
1958** function invokes sqlite3_changes() directly. Essentially:
1959**
1960** <ul>
1961**   <li> ^(Before entering a trigger program the value returned by
1962**        sqlite3_changes() function is saved. After the trigger program
1963**        has finished, the original value is restored.)^
1964**
1965**   <li> ^(Within a trigger program each INSERT, UPDATE and DELETE
1966**        statement sets the value returned by sqlite3_changes()
1967**        upon completion as normal. Of course, this value will not include
1968**        any changes performed by sub-triggers, as the sqlite3_changes()
1969**        value will be saved and restored after each sub-trigger has run.)^
1970** </ul>
1971**
1972** ^This means that if the changes() SQL function (or similar) is used
1973** by the first INSERT, UPDATE or DELETE statement within a trigger, it
1974** returns the value as set when the calling statement began executing.
1975** ^If it is used by the second or subsequent such statement within a trigger
1976** program, the value returned reflects the number of rows modified by the
1977** previous INSERT, UPDATE or DELETE statement within the same trigger.
1978**
1979** See also the [sqlite3_total_changes()] interface, the
1980** [count_changes pragma], and the [changes() SQL function].
1981**
1982** If a separate thread makes changes on the same database connection
1983** while [sqlite3_changes()] is running then the value returned
1984** is unpredictable and not meaningful.
1985*/
1986SQLITE_API int SQLITE_STDCALL sqlite3_changes(sqlite3*);
1987
1988/*
1989** CAPI3REF: Total Number Of Rows Modified
1990**
1991** ^This function returns the total number of rows inserted, modified or
1992** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed
1993** since the database connection was opened, including those executed as
1994** part of trigger programs. ^Executing any other type of SQL statement
1995** does not affect the value returned by sqlite3_total_changes().
1996**
1997** ^Changes made as part of [foreign key actions] are included in the
1998** count, but those made as part of REPLACE constraint resolution are
1999** not. ^Changes to a view that are intercepted by INSTEAD OF triggers
2000** are not counted.
2001**
2002** See also the [sqlite3_changes()] interface, the
2003** [count_changes pragma], and the [total_changes() SQL function].
2004**
2005** If a separate thread makes changes on the same database connection
2006** while [sqlite3_total_changes()] is running then the value
2007** returned is unpredictable and not meaningful.
2008*/
2009SQLITE_API int SQLITE_STDCALL sqlite3_total_changes(sqlite3*);
2010
2011/*
2012** CAPI3REF: Interrupt A Long-Running Query
2013**
2014** ^This function causes any pending database operation to abort and
2015** return at its earliest opportunity. This routine is typically
2016** called in response to a user action such as pressing "Cancel"
2017** or Ctrl-C where the user wants a long query operation to halt
2018** immediately.
2019**
2020** ^It is safe to call this routine from a thread different from the
2021** thread that is currently running the database operation.  But it
2022** is not safe to call this routine with a [database connection] that
2023** is closed or might close before sqlite3_interrupt() returns.
2024**
2025** ^If an SQL operation is very nearly finished at the time when
2026** sqlite3_interrupt() is called, then it might not have an opportunity
2027** to be interrupted and might continue to completion.
2028**
2029** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
2030** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
2031** that is inside an explicit transaction, then the entire transaction
2032** will be rolled back automatically.
2033**
2034** ^The sqlite3_interrupt(D) call is in effect until all currently running
2035** SQL statements on [database connection] D complete.  ^Any new SQL statements
2036** that are started after the sqlite3_interrupt() call and before the
2037** running statements reaches zero are interrupted as if they had been
2038** running prior to the sqlite3_interrupt() call.  ^New SQL statements
2039** that are started after the running statement count reaches zero are
2040** not effected by the sqlite3_interrupt().
2041** ^A call to sqlite3_interrupt(D) that occurs when there are no running
2042** SQL statements is a no-op and has no effect on SQL statements
2043** that are started after the sqlite3_interrupt() call returns.
2044**
2045** If the database connection closes while [sqlite3_interrupt()]
2046** is running then bad things will likely happen.
2047*/
2048SQLITE_API void SQLITE_STDCALL sqlite3_interrupt(sqlite3*);
2049
2050/*
2051** CAPI3REF: Determine If An SQL Statement Is Complete
2052**
2053** These routines are useful during command-line input to determine if the
2054** currently entered text seems to form a complete SQL statement or
2055** if additional input is needed before sending the text into
2056** SQLite for parsing.  ^These routines return 1 if the input string
2057** appears to be a complete SQL statement.  ^A statement is judged to be
2058** complete if it ends with a semicolon token and is not a prefix of a
2059** well-formed CREATE TRIGGER statement.  ^Semicolons that are embedded within
2060** string literals or quoted identifier names or comments are not
2061** independent tokens (they are part of the token in which they are
2062** embedded) and thus do not count as a statement terminator.  ^Whitespace
2063** and comments that follow the final semicolon are ignored.
2064**
2065** ^These routines return 0 if the statement is incomplete.  ^If a
2066** memory allocation fails, then SQLITE_NOMEM is returned.
2067**
2068** ^These routines do not parse the SQL statements thus
2069** will not detect syntactically incorrect SQL.
2070**
2071** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior
2072** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
2073** automatically by sqlite3_complete16().  If that initialization fails,
2074** then the return value from sqlite3_complete16() will be non-zero
2075** regardless of whether or not the input SQL is complete.)^
2076**
2077** The input to [sqlite3_complete()] must be a zero-terminated
2078** UTF-8 string.
2079**
2080** The input to [sqlite3_complete16()] must be a zero-terminated
2081** UTF-16 string in native byte order.
2082*/
2083SQLITE_API int SQLITE_STDCALL sqlite3_complete(const char *sql);
2084SQLITE_API int SQLITE_STDCALL sqlite3_complete16(const void *sql);
2085
2086/*
2087** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
2088** KEYWORDS: {busy-handler callback} {busy handler}
2089**
2090** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X
2091** that might be invoked with argument P whenever
2092** an attempt is made to access a database table associated with
2093** [database connection] D when another thread
2094** or process has the table locked.
2095** The sqlite3_busy_handler() interface is used to implement
2096** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout].
2097**
2098** ^If the busy callback is NULL, then [SQLITE_BUSY]
2099** is returned immediately upon encountering the lock.  ^If the busy callback
2100** is not NULL, then the callback might be invoked with two arguments.
2101**
2102** ^The first argument to the busy handler is a copy of the void* pointer which
2103** is the third argument to sqlite3_busy_handler().  ^The second argument to
2104** the busy handler callback is the number of times that the busy handler has
2105** been invoked previously for the same locking event.  ^If the
2106** busy callback returns 0, then no additional attempts are made to
2107** access the database and [SQLITE_BUSY] is returned
2108** to the application.
2109** ^If the callback returns non-zero, then another attempt
2110** is made to access the database and the cycle repeats.
2111**
2112** The presence of a busy handler does not guarantee that it will be invoked
2113** when there is lock contention. ^If SQLite determines that invoking the busy
2114** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
2115** to the application instead of invoking the
2116** busy handler.
2117** Consider a scenario where one process is holding a read lock that
2118** it is trying to promote to a reserved lock and
2119** a second process is holding a reserved lock that it is trying
2120** to promote to an exclusive lock.  The first process cannot proceed
2121** because it is blocked by the second and the second process cannot
2122** proceed because it is blocked by the first.  If both processes
2123** invoke the busy handlers, neither will make any progress.  Therefore,
2124** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
2125** will induce the first process to release its read lock and allow
2126** the second process to proceed.
2127**
2128** ^The default busy callback is NULL.
2129**
2130** ^(There can only be a single busy handler defined for each
2131** [database connection].  Setting a new busy handler clears any
2132** previously set handler.)^  ^Note that calling [sqlite3_busy_timeout()]
2133** or evaluating [PRAGMA busy_timeout=N] will change the
2134** busy handler and thus clear any previously set busy handler.
2135**
2136** The busy callback should not take any actions which modify the
2137** database connection that invoked the busy handler.  In other words,
2138** the busy handler is not reentrant.  Any such actions
2139** result in undefined behavior.
2140**
2141** A busy handler must not close the database connection
2142** or [prepared statement] that invoked the busy handler.
2143*/
2144SQLITE_API int SQLITE_STDCALL sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*);
2145
2146/*
2147** CAPI3REF: Set A Busy Timeout
2148**
2149** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
2150** for a specified amount of time when a table is locked.  ^The handler
2151** will sleep multiple times until at least "ms" milliseconds of sleeping
2152** have accumulated.  ^After at least "ms" milliseconds of sleeping,
2153** the handler returns 0 which causes [sqlite3_step()] to return
2154** [SQLITE_BUSY].
2155**
2156** ^Calling this routine with an argument less than or equal to zero
2157** turns off all busy handlers.
2158**
2159** ^(There can only be a single busy handler for a particular
2160** [database connection] at any given moment.  If another busy handler
2161** was defined  (using [sqlite3_busy_handler()]) prior to calling
2162** this routine, that other busy handler is cleared.)^
2163**
2164** See also:  [PRAGMA busy_timeout]
2165*/
2166SQLITE_API int SQLITE_STDCALL sqlite3_busy_timeout(sqlite3*, int ms);
2167
2168/*
2169** CAPI3REF: Convenience Routines For Running Queries
2170**
2171** This is a legacy interface that is preserved for backwards compatibility.
2172** Use of this interface is not recommended.
2173**
2174** Definition: A <b>result table</b> is memory data structure created by the
2175** [sqlite3_get_table()] interface.  A result table records the
2176** complete query results from one or more queries.
2177**
2178** The table conceptually has a number of rows and columns.  But
2179** these numbers are not part of the result table itself.  These
2180** numbers are obtained separately.  Let N be the number of rows
2181** and M be the number of columns.
2182**
2183** A result table is an array of pointers to zero-terminated UTF-8 strings.
2184** There are (N+1)*M elements in the array.  The first M pointers point
2185** to zero-terminated strings that  contain the names of the columns.
2186** The remaining entries all point to query results.  NULL values result
2187** in NULL pointers.  All other values are in their UTF-8 zero-terminated
2188** string representation as returned by [sqlite3_column_text()].
2189**
2190** A result table might consist of one or more memory allocations.
2191** It is not safe to pass a result table directly to [sqlite3_free()].
2192** A result table should be deallocated using [sqlite3_free_table()].
2193**
2194** ^(As an example of the result table format, suppose a query result
2195** is as follows:
2196**
2197** <blockquote><pre>
2198**        Name        | Age
2199**        -----------------------
2200**        Alice       | 43
2201**        Bob         | 28
2202**        Cindy       | 21
2203** </pre></blockquote>
2204**
2205** There are two column (M==2) and three rows (N==3).  Thus the
2206** result table has 8 entries.  Suppose the result table is stored
2207** in an array names azResult.  Then azResult holds this content:
2208**
2209** <blockquote><pre>
2210**        azResult&#91;0] = "Name";
2211**        azResult&#91;1] = "Age";
2212**        azResult&#91;2] = "Alice";
2213**        azResult&#91;3] = "43";
2214**        azResult&#91;4] = "Bob";
2215**        azResult&#91;5] = "28";
2216**        azResult&#91;6] = "Cindy";
2217**        azResult&#91;7] = "21";
2218** </pre></blockquote>)^
2219**
2220** ^The sqlite3_get_table() function evaluates one or more
2221** semicolon-separated SQL statements in the zero-terminated UTF-8
2222** string of its 2nd parameter and returns a result table to the
2223** pointer given in its 3rd parameter.
2224**
2225** After the application has finished with the result from sqlite3_get_table(),
2226** it must pass the result table pointer to sqlite3_free_table() in order to
2227** release the memory that was malloced.  Because of the way the
2228** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
2229** function must not try to call [sqlite3_free()] directly.  Only
2230** [sqlite3_free_table()] is able to release the memory properly and safely.
2231**
2232** The sqlite3_get_table() interface is implemented as a wrapper around
2233** [sqlite3_exec()].  The sqlite3_get_table() routine does not have access
2234** to any internal data structures of SQLite.  It uses only the public
2235** interface defined here.  As a consequence, errors that occur in the
2236** wrapper layer outside of the internal [sqlite3_exec()] call are not
2237** reflected in subsequent calls to [sqlite3_errcode()] or
2238** [sqlite3_errmsg()].
2239*/
2240SQLITE_API int SQLITE_STDCALL sqlite3_get_table(
2241  sqlite3 *db,          /* An open database */
2242  const char *zSql,     /* SQL to be evaluated */
2243  char ***pazResult,    /* Results of the query */
2244  int *pnRow,           /* Number of result rows written here */
2245  int *pnColumn,        /* Number of result columns written here */
2246  char **pzErrmsg       /* Error msg written here */
2247);
2248SQLITE_API void SQLITE_STDCALL sqlite3_free_table(char **result);
2249
2250/*
2251** CAPI3REF: Formatted String Printing Functions
2252**
2253** These routines are work-alikes of the "printf()" family of functions
2254** from the standard C library.
2255** These routines understand most of the common K&R formatting options,
2256** plus some additional non-standard formats, detailed below.
2257** Note that some of the more obscure formatting options from recent
2258** C-library standards are omitted from this implementation.
2259**
2260** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
2261** results into memory obtained from [sqlite3_malloc()].
2262** The strings returned by these two routines should be
2263** released by [sqlite3_free()].  ^Both routines return a
2264** NULL pointer if [sqlite3_malloc()] is unable to allocate enough
2265** memory to hold the resulting string.
2266**
2267** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
2268** the standard C library.  The result is written into the
2269** buffer supplied as the second parameter whose size is given by
2270** the first parameter. Note that the order of the
2271** first two parameters is reversed from snprintf().)^  This is an
2272** historical accident that cannot be fixed without breaking
2273** backwards compatibility.  ^(Note also that sqlite3_snprintf()
2274** returns a pointer to its buffer instead of the number of
2275** characters actually written into the buffer.)^  We admit that
2276** the number of characters written would be a more useful return
2277** value but we cannot change the implementation of sqlite3_snprintf()
2278** now without breaking compatibility.
2279**
2280** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
2281** guarantees that the buffer is always zero-terminated.  ^The first
2282** parameter "n" is the total size of the buffer, including space for
2283** the zero terminator.  So the longest string that can be completely
2284** written will be n-1 characters.
2285**
2286** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
2287**
2288** These routines all implement some additional formatting
2289** options that are useful for constructing SQL statements.
2290** All of the usual printf() formatting options apply.  In addition, there
2291** is are "%q", "%Q", "%w" and "%z" options.
2292**
2293** ^(The %q option works like %s in that it substitutes a nul-terminated
2294** string from the argument list.  But %q also doubles every '\'' character.
2295** %q is designed for use inside a string literal.)^  By doubling each '\''
2296** character it escapes that character and allows it to be inserted into
2297** the string.
2298**
2299** For example, assume the string variable zText contains text as follows:
2300**
2301** <blockquote><pre>
2302**  char *zText = "It's a happy day!";
2303** </pre></blockquote>
2304**
2305** One can use this text in an SQL statement as follows:
2306**
2307** <blockquote><pre>
2308**  char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText);
2309**  sqlite3_exec(db, zSQL, 0, 0, 0);
2310**  sqlite3_free(zSQL);
2311** </pre></blockquote>
2312**
2313** Because the %q format string is used, the '\'' character in zText
2314** is escaped and the SQL generated is as follows:
2315**
2316** <blockquote><pre>
2317**  INSERT INTO table1 VALUES('It''s a happy day!')
2318** </pre></blockquote>
2319**
2320** This is correct.  Had we used %s instead of %q, the generated SQL
2321** would have looked like this:
2322**
2323** <blockquote><pre>
2324**  INSERT INTO table1 VALUES('It's a happy day!');
2325** </pre></blockquote>
2326**
2327** This second example is an SQL syntax error.  As a general rule you should
2328** always use %q instead of %s when inserting text into a string literal.
2329**
2330** ^(The %Q option works like %q except it also adds single quotes around
2331** the outside of the total string.  Additionally, if the parameter in the
2332** argument list is a NULL pointer, %Q substitutes the text "NULL" (without
2333** single quotes).)^  So, for example, one could say:
2334**
2335** <blockquote><pre>
2336**  char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText);
2337**  sqlite3_exec(db, zSQL, 0, 0, 0);
2338**  sqlite3_free(zSQL);
2339** </pre></blockquote>
2340**
2341** The code above will render a correct SQL statement in the zSQL
2342** variable even if the zText variable is a NULL pointer.
2343**
2344** ^(The "%w" formatting option is like "%q" except that it expects to
2345** be contained within double-quotes instead of single quotes, and it
2346** escapes the double-quote character instead of the single-quote
2347** character.)^  The "%w" formatting option is intended for safely inserting
2348** table and column names into a constructed SQL statement.
2349**
2350** ^(The "%z" formatting option works like "%s" but with the
2351** addition that after the string has been read and copied into
2352** the result, [sqlite3_free()] is called on the input string.)^
2353*/
2354SQLITE_API char *SQLITE_CDECL sqlite3_mprintf(const char*,...);
2355SQLITE_API char *SQLITE_STDCALL sqlite3_vmprintf(const char*, va_list);
2356SQLITE_API char *SQLITE_CDECL sqlite3_snprintf(int,char*,const char*, ...);
2357SQLITE_API char *SQLITE_STDCALL sqlite3_vsnprintf(int,char*,const char*, va_list);
2358
2359/*
2360** CAPI3REF: Memory Allocation Subsystem
2361**
2362** The SQLite core uses these three routines for all of its own
2363** internal memory allocation needs. "Core" in the previous sentence
2364** does not include operating-system specific VFS implementation.  The
2365** Windows VFS uses native malloc() and free() for some operations.
2366**
2367** ^The sqlite3_malloc() routine returns a pointer to a block
2368** of memory at least N bytes in length, where N is the parameter.
2369** ^If sqlite3_malloc() is unable to obtain sufficient free
2370** memory, it returns a NULL pointer.  ^If the parameter N to
2371** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
2372** a NULL pointer.
2373**
2374** ^The sqlite3_malloc64(N) routine works just like
2375** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead
2376** of a signed 32-bit integer.
2377**
2378** ^Calling sqlite3_free() with a pointer previously returned
2379** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
2380** that it might be reused.  ^The sqlite3_free() routine is
2381** a no-op if is called with a NULL pointer.  Passing a NULL pointer
2382** to sqlite3_free() is harmless.  After being freed, memory
2383** should neither be read nor written.  Even reading previously freed
2384** memory might result in a segmentation fault or other severe error.
2385** Memory corruption, a segmentation fault, or other severe error
2386** might result if sqlite3_free() is called with a non-NULL pointer that
2387** was not obtained from sqlite3_malloc() or sqlite3_realloc().
2388**
2389** ^The sqlite3_realloc(X,N) interface attempts to resize a
2390** prior memory allocation X to be at least N bytes.
2391** ^If the X parameter to sqlite3_realloc(X,N)
2392** is a NULL pointer then its behavior is identical to calling
2393** sqlite3_malloc(N).
2394** ^If the N parameter to sqlite3_realloc(X,N) is zero or
2395** negative then the behavior is exactly the same as calling
2396** sqlite3_free(X).
2397** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation
2398** of at least N bytes in size or NULL if insufficient memory is available.
2399** ^If M is the size of the prior allocation, then min(N,M) bytes
2400** of the prior allocation are copied into the beginning of buffer returned
2401** by sqlite3_realloc(X,N) and the prior allocation is freed.
2402** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the
2403** prior allocation is not freed.
2404**
2405** ^The sqlite3_realloc64(X,N) interfaces works the same as
2406** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead
2407** of a 32-bit signed integer.
2408**
2409** ^If X is a memory allocation previously obtained from sqlite3_malloc(),
2410** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then
2411** sqlite3_msize(X) returns the size of that memory allocation in bytes.
2412** ^The value returned by sqlite3_msize(X) might be larger than the number
2413** of bytes requested when X was allocated.  ^If X is a NULL pointer then
2414** sqlite3_msize(X) returns zero.  If X points to something that is not
2415** the beginning of memory allocation, or if it points to a formerly
2416** valid memory allocation that has now been freed, then the behavior
2417** of sqlite3_msize(X) is undefined and possibly harmful.
2418**
2419** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(),
2420** sqlite3_malloc64(), and sqlite3_realloc64()
2421** is always aligned to at least an 8 byte boundary, or to a
2422** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
2423** option is used.
2424**
2425** In SQLite version 3.5.0 and 3.5.1, it was possible to define
2426** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in
2427** implementation of these routines to be omitted.  That capability
2428** is no longer provided.  Only built-in memory allocators can be used.
2429**
2430** Prior to SQLite version 3.7.10, the Windows OS interface layer called
2431** the system malloc() and free() directly when converting
2432** filenames between the UTF-8 encoding used by SQLite
2433** and whatever filename encoding is used by the particular Windows
2434** installation.  Memory allocation errors were detected, but
2435** they were reported back as [SQLITE_CANTOPEN] or
2436** [SQLITE_IOERR] rather than [SQLITE_NOMEM].
2437**
2438** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
2439** must be either NULL or else pointers obtained from a prior
2440** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
2441** not yet been released.
2442**
2443** The application must not read or write any part of
2444** a block of memory after it has been released using
2445** [sqlite3_free()] or [sqlite3_realloc()].
2446*/
2447SQLITE_API void *SQLITE_STDCALL sqlite3_malloc(int);
2448SQLITE_API void *SQLITE_STDCALL sqlite3_malloc64(sqlite3_uint64);
2449SQLITE_API void *SQLITE_STDCALL sqlite3_realloc(void*, int);
2450SQLITE_API void *SQLITE_STDCALL sqlite3_realloc64(void*, sqlite3_uint64);
2451SQLITE_API void SQLITE_STDCALL sqlite3_free(void*);
2452SQLITE_API sqlite3_uint64 SQLITE_STDCALL sqlite3_msize(void*);
2453
2454/*
2455** CAPI3REF: Memory Allocator Statistics
2456**
2457** SQLite provides these two interfaces for reporting on the status
2458** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
2459** routines, which form the built-in memory allocation subsystem.
2460**
2461** ^The [sqlite3_memory_used()] routine returns the number of bytes
2462** of memory currently outstanding (malloced but not freed).
2463** ^The [sqlite3_memory_highwater()] routine returns the maximum
2464** value of [sqlite3_memory_used()] since the high-water mark
2465** was last reset.  ^The values returned by [sqlite3_memory_used()] and
2466** [sqlite3_memory_highwater()] include any overhead
2467** added by SQLite in its implementation of [sqlite3_malloc()],
2468** but not overhead added by the any underlying system library
2469** routines that [sqlite3_malloc()] may call.
2470**
2471** ^The memory high-water mark is reset to the current value of
2472** [sqlite3_memory_used()] if and only if the parameter to
2473** [sqlite3_memory_highwater()] is true.  ^The value returned
2474** by [sqlite3_memory_highwater(1)] is the high-water mark
2475** prior to the reset.
2476*/
2477SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_memory_used(void);
2478SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_memory_highwater(int resetFlag);
2479
2480/*
2481** CAPI3REF: Pseudo-Random Number Generator
2482**
2483** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
2484** select random [ROWID | ROWIDs] when inserting new records into a table that
2485** already uses the largest possible [ROWID].  The PRNG is also used for
2486** the build-in random() and randomblob() SQL functions.  This interface allows
2487** applications to access the same PRNG for other purposes.
2488**
2489** ^A call to this routine stores N bytes of randomness into buffer P.
2490** ^The P parameter can be a NULL pointer.
2491**
2492** ^If this routine has not been previously called or if the previous
2493** call had N less than one or a NULL pointer for P, then the PRNG is
2494** seeded using randomness obtained from the xRandomness method of
2495** the default [sqlite3_vfs] object.
2496** ^If the previous call to this routine had an N of 1 or more and a
2497** non-NULL P then the pseudo-randomness is generated
2498** internally and without recourse to the [sqlite3_vfs] xRandomness
2499** method.
2500*/
2501SQLITE_API void SQLITE_STDCALL sqlite3_randomness(int N, void *P);
2502
2503/*
2504** CAPI3REF: Compile-Time Authorization Callbacks
2505**
2506** ^This routine registers an authorizer callback with a particular
2507** [database connection], supplied in the first argument.
2508** ^The authorizer callback is invoked as SQL statements are being compiled
2509** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
2510** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()].  ^At various
2511** points during the compilation process, as logic is being created
2512** to perform various actions, the authorizer callback is invoked to
2513** see if those actions are allowed.  ^The authorizer callback should
2514** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
2515** specific action but allow the SQL statement to continue to be
2516** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
2517** rejected with an error.  ^If the authorizer callback returns
2518** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
2519** then the [sqlite3_prepare_v2()] or equivalent call that triggered
2520** the authorizer will fail with an error message.
2521**
2522** When the callback returns [SQLITE_OK], that means the operation
2523** requested is ok.  ^When the callback returns [SQLITE_DENY], the
2524** [sqlite3_prepare_v2()] or equivalent call that triggered the
2525** authorizer will fail with an error message explaining that
2526** access is denied.
2527**
2528** ^The first parameter to the authorizer callback is a copy of the third
2529** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
2530** to the callback is an integer [SQLITE_COPY | action code] that specifies
2531** the particular action to be authorized. ^The third through sixth parameters
2532** to the callback are zero-terminated strings that contain additional
2533** details about the action to be authorized.
2534**
2535** ^If the action code is [SQLITE_READ]
2536** and the callback returns [SQLITE_IGNORE] then the
2537** [prepared statement] statement is constructed to substitute
2538** a NULL value in place of the table column that would have
2539** been read if [SQLITE_OK] had been returned.  The [SQLITE_IGNORE]
2540** return can be used to deny an untrusted user access to individual
2541** columns of a table.
2542** ^If the action code is [SQLITE_DELETE] and the callback returns
2543** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
2544** [truncate optimization] is disabled and all rows are deleted individually.
2545**
2546** An authorizer is used when [sqlite3_prepare | preparing]
2547** SQL statements from an untrusted source, to ensure that the SQL statements
2548** do not try to access data they are not allowed to see, or that they do not
2549** try to execute malicious statements that damage the database.  For
2550** example, an application may allow a user to enter arbitrary
2551** SQL queries for evaluation by a database.  But the application does
2552** not want the user to be able to make arbitrary changes to the
2553** database.  An authorizer could then be put in place while the
2554** user-entered SQL is being [sqlite3_prepare | prepared] that
2555** disallows everything except [SELECT] statements.
2556**
2557** Applications that need to process SQL from untrusted sources
2558** might also consider lowering resource limits using [sqlite3_limit()]
2559** and limiting database size using the [max_page_count] [PRAGMA]
2560** in addition to using an authorizer.
2561**
2562** ^(Only a single authorizer can be in place on a database connection
2563** at a time.  Each call to sqlite3_set_authorizer overrides the
2564** previous call.)^  ^Disable the authorizer by installing a NULL callback.
2565** The authorizer is disabled by default.
2566**
2567** The authorizer callback must not do anything that will modify
2568** the database connection that invoked the authorizer callback.
2569** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2570** database connections for the meaning of "modify" in this paragraph.
2571**
2572** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
2573** statement might be re-prepared during [sqlite3_step()] due to a
2574** schema change.  Hence, the application should ensure that the
2575** correct authorizer callback remains in place during the [sqlite3_step()].
2576**
2577** ^Note that the authorizer callback is invoked only during
2578** [sqlite3_prepare()] or its variants.  Authorization is not
2579** performed during statement evaluation in [sqlite3_step()], unless
2580** as stated in the previous paragraph, sqlite3_step() invokes
2581** sqlite3_prepare_v2() to reprepare a statement after a schema change.
2582*/
2583SQLITE_API int SQLITE_STDCALL sqlite3_set_authorizer(
2584  sqlite3*,
2585  int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
2586  void *pUserData
2587);
2588
2589/*
2590** CAPI3REF: Authorizer Return Codes
2591**
2592** The [sqlite3_set_authorizer | authorizer callback function] must
2593** return either [SQLITE_OK] or one of these two constants in order
2594** to signal SQLite whether or not the action is permitted.  See the
2595** [sqlite3_set_authorizer | authorizer documentation] for additional
2596** information.
2597**
2598** Note that SQLITE_IGNORE is also used as a [conflict resolution mode]
2599** returned from the [sqlite3_vtab_on_conflict()] interface.
2600*/
2601#define SQLITE_DENY   1   /* Abort the SQL statement with an error */
2602#define SQLITE_IGNORE 2   /* Don't allow access, but don't generate an error */
2603
2604/*
2605** CAPI3REF: Authorizer Action Codes
2606**
2607** The [sqlite3_set_authorizer()] interface registers a callback function
2608** that is invoked to authorize certain SQL statement actions.  The
2609** second parameter to the callback is an integer code that specifies
2610** what action is being authorized.  These are the integer action codes that
2611** the authorizer callback may be passed.
2612**
2613** These action code values signify what kind of operation is to be
2614** authorized.  The 3rd and 4th parameters to the authorization
2615** callback function will be parameters or NULL depending on which of these
2616** codes is used as the second parameter.  ^(The 5th parameter to the
2617** authorizer callback is the name of the database ("main", "temp",
2618** etc.) if applicable.)^  ^The 6th parameter to the authorizer callback
2619** is the name of the inner-most trigger or view that is responsible for
2620** the access attempt or NULL if this access attempt is directly from
2621** top-level SQL code.
2622*/
2623/******************************************* 3rd ************ 4th ***********/
2624#define SQLITE_CREATE_INDEX          1   /* Index Name      Table Name      */
2625#define SQLITE_CREATE_TABLE          2   /* Table Name      NULL            */
2626#define SQLITE_CREATE_TEMP_INDEX     3   /* Index Name      Table Name      */
2627#define SQLITE_CREATE_TEMP_TABLE     4   /* Table Name      NULL            */
2628#define SQLITE_CREATE_TEMP_TRIGGER   5   /* Trigger Name    Table Name      */
2629#define SQLITE_CREATE_TEMP_VIEW      6   /* View Name       NULL            */
2630#define SQLITE_CREATE_TRIGGER        7   /* Trigger Name    Table Name      */
2631#define SQLITE_CREATE_VIEW           8   /* View Name       NULL            */
2632#define SQLITE_DELETE                9   /* Table Name      NULL            */
2633#define SQLITE_DROP_INDEX           10   /* Index Name      Table Name      */
2634#define SQLITE_DROP_TABLE           11   /* Table Name      NULL            */
2635#define SQLITE_DROP_TEMP_INDEX      12   /* Index Name      Table Name      */
2636#define SQLITE_DROP_TEMP_TABLE      13   /* Table Name      NULL            */
2637#define SQLITE_DROP_TEMP_TRIGGER    14   /* Trigger Name    Table Name      */
2638#define SQLITE_DROP_TEMP_VIEW       15   /* View Name       NULL            */
2639#define SQLITE_DROP_TRIGGER         16   /* Trigger Name    Table Name      */
2640#define SQLITE_DROP_VIEW            17   /* View Name       NULL            */
2641#define SQLITE_INSERT               18   /* Table Name      NULL            */
2642#define SQLITE_PRAGMA               19   /* Pragma Name     1st arg or NULL */
2643#define SQLITE_READ                 20   /* Table Name      Column Name     */
2644#define SQLITE_SELECT               21   /* NULL            NULL            */
2645#define SQLITE_TRANSACTION          22   /* Operation       NULL            */
2646#define SQLITE_UPDATE               23   /* Table Name      Column Name     */
2647#define SQLITE_ATTACH               24   /* Filename        NULL            */
2648#define SQLITE_DETACH               25   /* Database Name   NULL            */
2649#define SQLITE_ALTER_TABLE          26   /* Database Name   Table Name      */
2650#define SQLITE_REINDEX              27   /* Index Name      NULL            */
2651#define SQLITE_ANALYZE              28   /* Table Name      NULL            */
2652#define SQLITE_CREATE_VTABLE        29   /* Table Name      Module Name     */
2653#define SQLITE_DROP_VTABLE          30   /* Table Name      Module Name     */
2654#define SQLITE_FUNCTION             31   /* NULL            Function Name   */
2655#define SQLITE_SAVEPOINT            32   /* Operation       Savepoint Name  */
2656#define SQLITE_COPY                  0   /* No longer used */
2657#define SQLITE_RECURSIVE            33   /* NULL            NULL            */
2658
2659/*
2660** CAPI3REF: Tracing And Profiling Functions
2661**
2662** These routines register callback functions that can be used for
2663** tracing and profiling the execution of SQL statements.
2664**
2665** ^The callback function registered by sqlite3_trace() is invoked at
2666** various times when an SQL statement is being run by [sqlite3_step()].
2667** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
2668** SQL statement text as the statement first begins executing.
2669** ^(Additional sqlite3_trace() callbacks might occur
2670** as each triggered subprogram is entered.  The callbacks for triggers
2671** contain a UTF-8 SQL comment that identifies the trigger.)^
2672**
2673** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit
2674** the length of [bound parameter] expansion in the output of sqlite3_trace().
2675**
2676** ^The callback function registered by sqlite3_profile() is invoked
2677** as each SQL statement finishes.  ^The profile callback contains
2678** the original statement text and an estimate of wall-clock time
2679** of how long that statement took to run.  ^The profile callback
2680** time is in units of nanoseconds, however the current implementation
2681** is only capable of millisecond resolution so the six least significant
2682** digits in the time are meaningless.  Future versions of SQLite
2683** might provide greater resolution on the profiler callback.  The
2684** sqlite3_profile() function is considered experimental and is
2685** subject to change in future versions of SQLite.
2686*/
2687SQLITE_API void *SQLITE_STDCALL sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*);
2688SQLITE_API SQLITE_EXPERIMENTAL void *SQLITE_STDCALL sqlite3_profile(sqlite3*,
2689   void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
2690
2691/*
2692** CAPI3REF: Query Progress Callbacks
2693**
2694** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
2695** function X to be invoked periodically during long running calls to
2696** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for
2697** database connection D.  An example use for this
2698** interface is to keep a GUI updated during a large query.
2699**
2700** ^The parameter P is passed through as the only parameter to the
2701** callback function X.  ^The parameter N is the approximate number of
2702** [virtual machine instructions] that are evaluated between successive
2703** invocations of the callback X.  ^If N is less than one then the progress
2704** handler is disabled.
2705**
2706** ^Only a single progress handler may be defined at one time per
2707** [database connection]; setting a new progress handler cancels the
2708** old one.  ^Setting parameter X to NULL disables the progress handler.
2709** ^The progress handler is also disabled by setting N to a value less
2710** than 1.
2711**
2712** ^If the progress callback returns non-zero, the operation is
2713** interrupted.  This feature can be used to implement a
2714** "Cancel" button on a GUI progress dialog box.
2715**
2716** The progress handler callback must not do anything that will modify
2717** the database connection that invoked the progress handler.
2718** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2719** database connections for the meaning of "modify" in this paragraph.
2720**
2721*/
2722SQLITE_API void SQLITE_STDCALL sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
2723
2724/*
2725** CAPI3REF: Opening A New Database Connection
2726**
2727** ^These routines open an SQLite database file as specified by the
2728** filename argument. ^The filename argument is interpreted as UTF-8 for
2729** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
2730** order for sqlite3_open16(). ^(A [database connection] handle is usually
2731** returned in *ppDb, even if an error occurs.  The only exception is that
2732** if SQLite is unable to allocate memory to hold the [sqlite3] object,
2733** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
2734** object.)^ ^(If the database is opened (and/or created) successfully, then
2735** [SQLITE_OK] is returned.  Otherwise an [error code] is returned.)^ ^The
2736** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
2737** an English language description of the error following a failure of any
2738** of the sqlite3_open() routines.
2739**
2740** ^The default encoding will be UTF-8 for databases created using
2741** sqlite3_open() or sqlite3_open_v2().  ^The default encoding for databases
2742** created using sqlite3_open16() will be UTF-16 in the native byte order.
2743**
2744** Whether or not an error occurs when it is opened, resources
2745** associated with the [database connection] handle should be released by
2746** passing it to [sqlite3_close()] when it is no longer required.
2747**
2748** The sqlite3_open_v2() interface works like sqlite3_open()
2749** except that it accepts two additional parameters for additional control
2750** over the new database connection.  ^(The flags parameter to
2751** sqlite3_open_v2() can take one of
2752** the following three values, optionally combined with the
2753** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE],
2754** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^
2755**
2756** <dl>
2757** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
2758** <dd>The database is opened in read-only mode.  If the database does not
2759** already exist, an error is returned.</dd>)^
2760**
2761** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
2762** <dd>The database is opened for reading and writing if possible, or reading
2763** only if the file is write protected by the operating system.  In either
2764** case the database must already exist, otherwise an error is returned.</dd>)^
2765**
2766** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
2767** <dd>The database is opened for reading and writing, and is created if
2768** it does not already exist. This is the behavior that is always used for
2769** sqlite3_open() and sqlite3_open16().</dd>)^
2770** </dl>
2771**
2772** If the 3rd parameter to sqlite3_open_v2() is not one of the
2773** combinations shown above optionally combined with other
2774** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits]
2775** then the behavior is undefined.
2776**
2777** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection
2778** opens in the multi-thread [threading mode] as long as the single-thread
2779** mode has not been set at compile-time or start-time.  ^If the
2780** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens
2781** in the serialized [threading mode] unless single-thread was
2782** previously selected at compile-time or start-time.
2783** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be
2784** eligible to use [shared cache mode], regardless of whether or not shared
2785** cache is enabled using [sqlite3_enable_shared_cache()].  ^The
2786** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not
2787** participate in [shared cache mode] even if it is enabled.
2788**
2789** ^The fourth parameter to sqlite3_open_v2() is the name of the
2790** [sqlite3_vfs] object that defines the operating system interface that
2791** the new database connection should use.  ^If the fourth parameter is
2792** a NULL pointer then the default [sqlite3_vfs] object is used.
2793**
2794** ^If the filename is ":memory:", then a private, temporary in-memory database
2795** is created for the connection.  ^This in-memory database will vanish when
2796** the database connection is closed.  Future versions of SQLite might
2797** make use of additional special filenames that begin with the ":" character.
2798** It is recommended that when a database filename actually does begin with
2799** a ":" character you should prefix the filename with a pathname such as
2800** "./" to avoid ambiguity.
2801**
2802** ^If the filename is an empty string, then a private, temporary
2803** on-disk database will be created.  ^This private database will be
2804** automatically deleted as soon as the database connection is closed.
2805**
2806** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
2807**
2808** ^If [URI filename] interpretation is enabled, and the filename argument
2809** begins with "file:", then the filename is interpreted as a URI. ^URI
2810** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
2811** set in the fourth argument to sqlite3_open_v2(), or if it has
2812** been enabled globally using the [SQLITE_CONFIG_URI] option with the
2813** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
2814** As of SQLite version 3.7.7, URI filename interpretation is turned off
2815** by default, but future releases of SQLite might enable URI filename
2816** interpretation by default.  See "[URI filenames]" for additional
2817** information.
2818**
2819** URI filenames are parsed according to RFC 3986. ^If the URI contains an
2820** authority, then it must be either an empty string or the string
2821** "localhost". ^If the authority is not an empty string or "localhost", an
2822** error is returned to the caller. ^The fragment component of a URI, if
2823** present, is ignored.
2824**
2825** ^SQLite uses the path component of the URI as the name of the disk file
2826** which contains the database. ^If the path begins with a '/' character,
2827** then it is interpreted as an absolute path. ^If the path does not begin
2828** with a '/' (meaning that the authority section is omitted from the URI)
2829** then the path is interpreted as a relative path.
2830** ^(On windows, the first component of an absolute path
2831** is a drive specification (e.g. "C:").)^
2832**
2833** [[core URI query parameters]]
2834** The query component of a URI may contain parameters that are interpreted
2835** either by SQLite itself, or by a [VFS | custom VFS implementation].
2836** SQLite and its built-in [VFSes] interpret the
2837** following query parameters:
2838**
2839** <ul>
2840**   <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
2841**     a VFS object that provides the operating system interface that should
2842**     be used to access the database file on disk. ^If this option is set to
2843**     an empty string the default VFS object is used. ^Specifying an unknown
2844**     VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
2845**     present, then the VFS specified by the option takes precedence over
2846**     the value passed as the fourth parameter to sqlite3_open_v2().
2847**
2848**   <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw",
2849**     "rwc", or "memory". Attempting to set it to any other value is
2850**     an error)^.
2851**     ^If "ro" is specified, then the database is opened for read-only
2852**     access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the
2853**     third argument to sqlite3_open_v2(). ^If the mode option is set to
2854**     "rw", then the database is opened for read-write (but not create)
2855**     access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had
2856**     been set. ^Value "rwc" is equivalent to setting both
2857**     SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE.  ^If the mode option is
2858**     set to "memory" then a pure [in-memory database] that never reads
2859**     or writes from disk is used. ^It is an error to specify a value for
2860**     the mode parameter that is less restrictive than that specified by
2861**     the flags passed in the third parameter to sqlite3_open_v2().
2862**
2863**   <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
2864**     "private". ^Setting it to "shared" is equivalent to setting the
2865**     SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
2866**     sqlite3_open_v2(). ^Setting the cache parameter to "private" is
2867**     equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
2868**     ^If sqlite3_open_v2() is used and the "cache" parameter is present in
2869**     a URI filename, its value overrides any behavior requested by setting
2870**     SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.
2871**
2872**  <li> <b>psow</b>: ^The psow parameter indicates whether or not the
2873**     [powersafe overwrite] property does or does not apply to the
2874**     storage media on which the database file resides.
2875**
2876**  <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter
2877**     which if set disables file locking in rollback journal modes.  This
2878**     is useful for accessing a database on a filesystem that does not
2879**     support locking.  Caution:  Database corruption might result if two
2880**     or more processes write to the same database and any one of those
2881**     processes uses nolock=1.
2882**
2883**  <li> <b>immutable</b>: ^The immutable parameter is a boolean query
2884**     parameter that indicates that the database file is stored on
2885**     read-only media.  ^When immutable is set, SQLite assumes that the
2886**     database file cannot be changed, even by a process with higher
2887**     privilege, and so the database is opened read-only and all locking
2888**     and change detection is disabled.  Caution: Setting the immutable
2889**     property on a database file that does in fact change can result
2890**     in incorrect query results and/or [SQLITE_CORRUPT] errors.
2891**     See also: [SQLITE_IOCAP_IMMUTABLE].
2892**
2893** </ul>
2894**
2895** ^Specifying an unknown parameter in the query component of a URI is not an
2896** error.  Future versions of SQLite might understand additional query
2897** parameters.  See "[query parameters with special meaning to SQLite]" for
2898** additional information.
2899**
2900** [[URI filename examples]] <h3>URI filename examples</h3>
2901**
2902** <table border="1" align=center cellpadding=5>
2903** <tr><th> URI filenames <th> Results
2904** <tr><td> file:data.db <td>
2905**          Open the file "data.db" in the current directory.
2906** <tr><td> file:/home/fred/data.db<br>
2907**          file:///home/fred/data.db <br>
2908**          file://localhost/home/fred/data.db <br> <td>
2909**          Open the database file "/home/fred/data.db".
2910** <tr><td> file://darkstar/home/fred/data.db <td>
2911**          An error. "darkstar" is not a recognized authority.
2912** <tr><td style="white-space:nowrap">
2913**          file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
2914**     <td> Windows only: Open the file "data.db" on fred's desktop on drive
2915**          C:. Note that the %20 escaping in this example is not strictly
2916**          necessary - space characters can be used literally
2917**          in URI filenames.
2918** <tr><td> file:data.db?mode=ro&cache=private <td>
2919**          Open file "data.db" in the current directory for read-only access.
2920**          Regardless of whether or not shared-cache mode is enabled by
2921**          default, use a private cache.
2922** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td>
2923**          Open file "/home/fred/data.db". Use the special VFS "unix-dotfile"
2924**          that uses dot-files in place of posix advisory locking.
2925** <tr><td> file:data.db?mode=readonly <td>
2926**          An error. "readonly" is not a valid option for the "mode" parameter.
2927** </table>
2928**
2929** ^URI hexadecimal escape sequences (%HH) are supported within the path and
2930** query components of a URI. A hexadecimal escape sequence consists of a
2931** percent sign - "%" - followed by exactly two hexadecimal digits
2932** specifying an octet value. ^Before the path or query components of a
2933** URI filename are interpreted, they are encoded using UTF-8 and all
2934** hexadecimal escape sequences replaced by a single byte containing the
2935** corresponding octet. If this process generates an invalid UTF-8 encoding,
2936** the results are undefined.
2937**
2938** <b>Note to Windows users:</b>  The encoding used for the filename argument
2939** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
2940** codepage is currently defined.  Filenames containing international
2941** characters must be converted to UTF-8 prior to passing them into
2942** sqlite3_open() or sqlite3_open_v2().
2943**
2944** <b>Note to Windows Runtime users:</b>  The temporary directory must be set
2945** prior to calling sqlite3_open() or sqlite3_open_v2().  Otherwise, various
2946** features that require the use of temporary files may fail.
2947**
2948** See also: [sqlite3_temp_directory]
2949*/
2950SQLITE_API int SQLITE_STDCALL sqlite3_open(
2951  const char *filename,   /* Database filename (UTF-8) */
2952  sqlite3 **ppDb          /* OUT: SQLite db handle */
2953);
2954SQLITE_API int SQLITE_STDCALL sqlite3_open16(
2955  const void *filename,   /* Database filename (UTF-16) */
2956  sqlite3 **ppDb          /* OUT: SQLite db handle */
2957);
2958SQLITE_API int SQLITE_STDCALL sqlite3_open_v2(
2959  const char *filename,   /* Database filename (UTF-8) */
2960  sqlite3 **ppDb,         /* OUT: SQLite db handle */
2961  int flags,              /* Flags */
2962  const char *zVfs        /* Name of VFS module to use */
2963);
2964
2965/*
2966** CAPI3REF: Obtain Values For URI Parameters
2967**
2968** These are utility routines, useful to VFS implementations, that check
2969** to see if a database file was a URI that contained a specific query
2970** parameter, and if so obtains the value of that query parameter.
2971**
2972** If F is the database filename pointer passed into the xOpen() method of
2973** a VFS implementation when the flags parameter to xOpen() has one or
2974** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and
2975** P is the name of the query parameter, then
2976** sqlite3_uri_parameter(F,P) returns the value of the P
2977** parameter if it exists or a NULL pointer if P does not appear as a
2978** query parameter on F.  If P is a query parameter of F
2979** has no explicit value, then sqlite3_uri_parameter(F,P) returns
2980** a pointer to an empty string.
2981**
2982** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
2983** parameter and returns true (1) or false (0) according to the value
2984** of P.  The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
2985** value of query parameter P is one of "yes", "true", or "on" in any
2986** case or if the value begins with a non-zero number.  The
2987** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
2988** query parameter P is one of "no", "false", or "off" in any case or
2989** if the value begins with a numeric zero.  If P is not a query
2990** parameter on F or if the value of P is does not match any of the
2991** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).
2992**
2993** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
2994** 64-bit signed integer and returns that integer, or D if P does not
2995** exist.  If the value of P is something other than an integer, then
2996** zero is returned.
2997**
2998** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
2999** sqlite3_uri_boolean(F,P,B) returns B.  If F is not a NULL pointer and
3000** is not a database file pathname pointer that SQLite passed into the xOpen
3001** VFS method, then the behavior of this routine is undefined and probably
3002** undesirable.
3003*/
3004SQLITE_API const char *SQLITE_STDCALL sqlite3_uri_parameter(const char *zFilename, const char *zParam);
3005SQLITE_API int SQLITE_STDCALL sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault);
3006SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_uri_int64(const char*, const char*, sqlite3_int64);
3007
3008
3009/*
3010** CAPI3REF: Error Codes And Messages
3011**
3012** ^If the most recent sqlite3_* API call associated with
3013** [database connection] D failed, then the sqlite3_errcode(D) interface
3014** returns the numeric [result code] or [extended result code] for that
3015** API call.
3016** If the most recent API call was successful,
3017** then the return value from sqlite3_errcode() is undefined.
3018** ^The sqlite3_extended_errcode()
3019** interface is the same except that it always returns the
3020** [extended result code] even when extended result codes are
3021** disabled.
3022**
3023** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
3024** text that describes the error, as either UTF-8 or UTF-16 respectively.
3025** ^(Memory to hold the error message string is managed internally.
3026** The application does not need to worry about freeing the result.
3027** However, the error string might be overwritten or deallocated by
3028** subsequent calls to other SQLite interface functions.)^
3029**
3030** ^The sqlite3_errstr() interface returns the English-language text
3031** that describes the [result code], as UTF-8.
3032** ^(Memory to hold the error message string is managed internally
3033** and must not be freed by the application)^.
3034**
3035** When the serialized [threading mode] is in use, it might be the
3036** case that a second error occurs on a separate thread in between
3037** the time of the first error and the call to these interfaces.
3038** When that happens, the second error will be reported since these
3039** interfaces always report the most recent result.  To avoid
3040** this, each thread can obtain exclusive use of the [database connection] D
3041** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
3042** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
3043** all calls to the interfaces listed here are completed.
3044**
3045** If an interface fails with SQLITE_MISUSE, that means the interface
3046** was invoked incorrectly by the application.  In that case, the
3047** error code and message may or may not be set.
3048*/
3049SQLITE_API int SQLITE_STDCALL sqlite3_errcode(sqlite3 *db);
3050SQLITE_API int SQLITE_STDCALL sqlite3_extended_errcode(sqlite3 *db);
3051SQLITE_API const char *SQLITE_STDCALL sqlite3_errmsg(sqlite3*);
3052SQLITE_API const void *SQLITE_STDCALL sqlite3_errmsg16(sqlite3*);
3053SQLITE_API const char *SQLITE_STDCALL sqlite3_errstr(int);
3054
3055/*
3056** CAPI3REF: SQL Statement Object
3057** KEYWORDS: {prepared statement} {prepared statements}
3058**
3059** An instance of this object represents a single SQL statement.
3060** This object is variously known as a "prepared statement" or a
3061** "compiled SQL statement" or simply as a "statement".
3062**
3063** The life of a statement object goes something like this:
3064**
3065** <ol>
3066** <li> Create the object using [sqlite3_prepare_v2()] or a related
3067**      function.
3068** <li> Bind values to [host parameters] using the sqlite3_bind_*()
3069**      interfaces.
3070** <li> Run the SQL by calling [sqlite3_step()] one or more times.
3071** <li> Reset the statement using [sqlite3_reset()] then go back
3072**      to step 2.  Do this zero or more times.
3073** <li> Destroy the object using [sqlite3_finalize()].
3074** </ol>
3075**
3076** Refer to documentation on individual methods above for additional
3077** information.
3078*/
3079typedef struct sqlite3_stmt sqlite3_stmt;
3080
3081/*
3082** CAPI3REF: Run-time Limits
3083**
3084** ^(This interface allows the size of various constructs to be limited
3085** on a connection by connection basis.  The first parameter is the
3086** [database connection] whose limit is to be set or queried.  The
3087** second parameter is one of the [limit categories] that define a
3088** class of constructs to be size limited.  The third parameter is the
3089** new limit for that construct.)^
3090**
3091** ^If the new limit is a negative number, the limit is unchanged.
3092** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
3093** [limits | hard upper bound]
3094** set at compile-time by a C preprocessor macro called
3095** [limits | SQLITE_MAX_<i>NAME</i>].
3096** (The "_LIMIT_" in the name is changed to "_MAX_".))^
3097** ^Attempts to increase a limit above its hard upper bound are
3098** silently truncated to the hard upper bound.
3099**
3100** ^Regardless of whether or not the limit was changed, the
3101** [sqlite3_limit()] interface returns the prior value of the limit.
3102** ^Hence, to find the current value of a limit without changing it,
3103** simply invoke this interface with the third parameter set to -1.
3104**
3105** Run-time limits are intended for use in applications that manage
3106** both their own internal database and also databases that are controlled
3107** by untrusted external sources.  An example application might be a
3108** web browser that has its own databases for storing history and
3109** separate databases controlled by JavaScript applications downloaded
3110** off the Internet.  The internal databases can be given the
3111** large, default limits.  Databases managed by external sources can
3112** be given much smaller limits designed to prevent a denial of service
3113** attack.  Developers might also want to use the [sqlite3_set_authorizer()]
3114** interface to further control untrusted SQL.  The size of the database
3115** created by an untrusted script can be contained using the
3116** [max_page_count] [PRAGMA].
3117**
3118** New run-time limit categories may be added in future releases.
3119*/
3120SQLITE_API int SQLITE_STDCALL sqlite3_limit(sqlite3*, int id, int newVal);
3121
3122/*
3123** CAPI3REF: Run-Time Limit Categories
3124** KEYWORDS: {limit category} {*limit categories}
3125**
3126** These constants define various performance limits
3127** that can be lowered at run-time using [sqlite3_limit()].
3128** The synopsis of the meanings of the various limits is shown below.
3129** Additional information is available at [limits | Limits in SQLite].
3130**
3131** <dl>
3132** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt>
3133** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
3134**
3135** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
3136** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
3137**
3138** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt>
3139** <dd>The maximum number of columns in a table definition or in the
3140** result set of a [SELECT] or the maximum number of columns in an index
3141** or in an ORDER BY or GROUP BY clause.</dd>)^
3142**
3143** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
3144** <dd>The maximum depth of the parse tree on any expression.</dd>)^
3145**
3146** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
3147** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
3148**
3149** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
3150** <dd>The maximum number of instructions in a virtual machine program
3151** used to implement an SQL statement.  This limit is not currently
3152** enforced, though that might be added in some future release of
3153** SQLite.</dd>)^
3154**
3155** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
3156** <dd>The maximum number of arguments on a function.</dd>)^
3157**
3158** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
3159** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
3160**
3161** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]]
3162** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
3163** <dd>The maximum length of the pattern argument to the [LIKE] or
3164** [GLOB] operators.</dd>)^
3165**
3166** [[SQLITE_LIMIT_VARIABLE_NUMBER]]
3167** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
3168** <dd>The maximum index number of any [parameter] in an SQL statement.)^
3169**
3170** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
3171** <dd>The maximum depth of recursion for triggers.</dd>)^
3172**
3173** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt>
3174** <dd>The maximum number of auxiliary worker threads that a single
3175** [prepared statement] may start.</dd>)^
3176** </dl>
3177*/
3178#define SQLITE_LIMIT_LENGTH                    0
3179#define SQLITE_LIMIT_SQL_LENGTH                1
3180#define SQLITE_LIMIT_COLUMN                    2
3181#define SQLITE_LIMIT_EXPR_DEPTH                3
3182#define SQLITE_LIMIT_COMPOUND_SELECT           4
3183#define SQLITE_LIMIT_VDBE_OP                   5
3184#define SQLITE_LIMIT_FUNCTION_ARG              6
3185#define SQLITE_LIMIT_ATTACHED                  7
3186#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH       8
3187#define SQLITE_LIMIT_VARIABLE_NUMBER           9
3188#define SQLITE_LIMIT_TRIGGER_DEPTH            10
3189#define SQLITE_LIMIT_WORKER_THREADS           11
3190
3191/*
3192** CAPI3REF: Compiling An SQL Statement
3193** KEYWORDS: {SQL statement compiler}
3194**
3195** To execute an SQL query, it must first be compiled into a byte-code
3196** program using one of these routines.
3197**
3198** The first argument, "db", is a [database connection] obtained from a
3199** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
3200** [sqlite3_open16()].  The database connection must not have been closed.
3201**
3202** The second argument, "zSql", is the statement to be compiled, encoded
3203** as either UTF-8 or UTF-16.  The sqlite3_prepare() and sqlite3_prepare_v2()
3204** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2()
3205** use UTF-16.
3206**
3207** ^If the nByte argument is negative, then zSql is read up to the
3208** first zero terminator. ^If nByte is positive, then it is the
3209** number of bytes read from zSql.  ^If nByte is zero, then no prepared
3210** statement is generated.
3211** If the caller knows that the supplied string is nul-terminated, then
3212** there is a small performance advantage to passing an nByte parameter that
3213** is the number of bytes in the input string <i>including</i>
3214** the nul-terminator.
3215**
3216** ^If pzTail is not NULL then *pzTail is made to point to the first byte
3217** past the end of the first SQL statement in zSql.  These routines only
3218** compile the first statement in zSql, so *pzTail is left pointing to
3219** what remains uncompiled.
3220**
3221** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
3222** executed using [sqlite3_step()].  ^If there is an error, *ppStmt is set
3223** to NULL.  ^If the input text contains no SQL (if the input is an empty
3224** string or a comment) then *ppStmt is set to NULL.
3225** The calling procedure is responsible for deleting the compiled
3226** SQL statement using [sqlite3_finalize()] after it has finished with it.
3227** ppStmt may not be NULL.
3228**
3229** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
3230** otherwise an [error code] is returned.
3231**
3232** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are
3233** recommended for all new programs. The two older interfaces are retained
3234** for backwards compatibility, but their use is discouraged.
3235** ^In the "v2" interfaces, the prepared statement
3236** that is returned (the [sqlite3_stmt] object) contains a copy of the
3237** original SQL text. This causes the [sqlite3_step()] interface to
3238** behave differently in three ways:
3239**
3240** <ol>
3241** <li>
3242** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
3243** always used to do, [sqlite3_step()] will automatically recompile the SQL
3244** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY]
3245** retries will occur before sqlite3_step() gives up and returns an error.
3246** </li>
3247**
3248** <li>
3249** ^When an error occurs, [sqlite3_step()] will return one of the detailed
3250** [error codes] or [extended error codes].  ^The legacy behavior was that
3251** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
3252** and the application would have to make a second call to [sqlite3_reset()]
3253** in order to find the underlying cause of the problem. With the "v2" prepare
3254** interfaces, the underlying reason for the error is returned immediately.
3255** </li>
3256**
3257** <li>
3258** ^If the specific value bound to [parameter | host parameter] in the
3259** WHERE clause might influence the choice of query plan for a statement,
3260** then the statement will be automatically recompiled, as if there had been
3261** a schema change, on the first  [sqlite3_step()] call following any change
3262** to the [sqlite3_bind_text | bindings] of that [parameter].
3263** ^The specific value of WHERE-clause [parameter] might influence the
3264** choice of query plan if the parameter is the left-hand side of a [LIKE]
3265** or [GLOB] operator or if the parameter is compared to an indexed column
3266** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled.
3267** </li>
3268** </ol>
3269*/
3270SQLITE_API int SQLITE_STDCALL sqlite3_prepare(
3271  sqlite3 *db,            /* Database handle */
3272  const char *zSql,       /* SQL statement, UTF-8 encoded */
3273  int nByte,              /* Maximum length of zSql in bytes. */
3274  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
3275  const char **pzTail     /* OUT: Pointer to unused portion of zSql */
3276);
3277SQLITE_API int SQLITE_STDCALL sqlite3_prepare_v2(
3278  sqlite3 *db,            /* Database handle */
3279  const char *zSql,       /* SQL statement, UTF-8 encoded */
3280  int nByte,              /* Maximum length of zSql in bytes. */
3281  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
3282  const char **pzTail     /* OUT: Pointer to unused portion of zSql */
3283);
3284SQLITE_API int SQLITE_STDCALL sqlite3_prepare16(
3285  sqlite3 *db,            /* Database handle */
3286  const void *zSql,       /* SQL statement, UTF-16 encoded */
3287  int nByte,              /* Maximum length of zSql in bytes. */
3288  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
3289  const void **pzTail     /* OUT: Pointer to unused portion of zSql */
3290);
3291SQLITE_API int SQLITE_STDCALL sqlite3_prepare16_v2(
3292  sqlite3 *db,            /* Database handle */
3293  const void *zSql,       /* SQL statement, UTF-16 encoded */
3294  int nByte,              /* Maximum length of zSql in bytes. */
3295  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
3296  const void **pzTail     /* OUT: Pointer to unused portion of zSql */
3297);
3298
3299/*
3300** CAPI3REF: Retrieving Statement SQL
3301**
3302** ^This interface can be used to retrieve a saved copy of the original
3303** SQL text used to create a [prepared statement] if that statement was
3304** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()].
3305*/
3306SQLITE_API const char *SQLITE_STDCALL sqlite3_sql(sqlite3_stmt *pStmt);
3307
3308/*
3309** CAPI3REF: Determine If An SQL Statement Writes The Database
3310**
3311** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
3312** and only if the [prepared statement] X makes no direct changes to
3313** the content of the database file.
3314**
3315** Note that [application-defined SQL functions] or
3316** [virtual tables] might change the database indirectly as a side effect.
3317** ^(For example, if an application defines a function "eval()" that
3318** calls [sqlite3_exec()], then the following SQL statement would
3319** change the database file through side-effects:
3320**
3321** <blockquote><pre>
3322**    SELECT eval('DELETE FROM t1') FROM t2;
3323** </pre></blockquote>
3324**
3325** But because the [SELECT] statement does not change the database file
3326** directly, sqlite3_stmt_readonly() would still return true.)^
3327**
3328** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
3329** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
3330** since the statements themselves do not actually modify the database but
3331** rather they control the timing of when other statements modify the
3332** database.  ^The [ATTACH] and [DETACH] statements also cause
3333** sqlite3_stmt_readonly() to return true since, while those statements
3334** change the configuration of a database connection, they do not make
3335** changes to the content of the database files on disk.
3336*/
3337SQLITE_API int SQLITE_STDCALL sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
3338
3339/*
3340** CAPI3REF: Determine If A Prepared Statement Has Been Reset
3341**
3342** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
3343** [prepared statement] S has been stepped at least once using
3344** [sqlite3_step(S)] but has not run to completion and/or has not
3345** been reset using [sqlite3_reset(S)].  ^The sqlite3_stmt_busy(S)
3346** interface returns false if S is a NULL pointer.  If S is not a
3347** NULL pointer and is not a pointer to a valid [prepared statement]
3348** object, then the behavior is undefined and probably undesirable.
3349**
3350** This interface can be used in combination [sqlite3_next_stmt()]
3351** to locate all prepared statements associated with a database
3352** connection that are in need of being reset.  This can be used,
3353** for example, in diagnostic routines to search for prepared
3354** statements that are holding a transaction open.
3355*/
3356SQLITE_API int SQLITE_STDCALL sqlite3_stmt_busy(sqlite3_stmt*);
3357
3358/*
3359** CAPI3REF: Dynamically Typed Value Object
3360** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
3361**
3362** SQLite uses the sqlite3_value object to represent all values
3363** that can be stored in a database table. SQLite uses dynamic typing
3364** for the values it stores.  ^Values stored in sqlite3_value objects
3365** can be integers, floating point values, strings, BLOBs, or NULL.
3366**
3367** An sqlite3_value object may be either "protected" or "unprotected".
3368** Some interfaces require a protected sqlite3_value.  Other interfaces
3369** will accept either a protected or an unprotected sqlite3_value.
3370** Every interface that accepts sqlite3_value arguments specifies
3371** whether or not it requires a protected sqlite3_value.
3372**
3373** The terms "protected" and "unprotected" refer to whether or not
3374** a mutex is held.  An internal mutex is held for a protected
3375** sqlite3_value object but no mutex is held for an unprotected
3376** sqlite3_value object.  If SQLite is compiled to be single-threaded
3377** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
3378** or if SQLite is run in one of reduced mutex modes
3379** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
3380** then there is no distinction between protected and unprotected
3381** sqlite3_value objects and they can be used interchangeably.  However,
3382** for maximum code portability it is recommended that applications
3383** still make the distinction between protected and unprotected
3384** sqlite3_value objects even when not strictly required.
3385**
3386** ^The sqlite3_value objects that are passed as parameters into the
3387** implementation of [application-defined SQL functions] are protected.
3388** ^The sqlite3_value object returned by
3389** [sqlite3_column_value()] is unprotected.
3390** Unprotected sqlite3_value objects may only be used with
3391** [sqlite3_result_value()] and [sqlite3_bind_value()].
3392** The [sqlite3_value_blob | sqlite3_value_type()] family of
3393** interfaces require protected sqlite3_value objects.
3394*/
3395typedef struct Mem sqlite3_value;
3396
3397/*
3398** CAPI3REF: SQL Function Context Object
3399**
3400** The context in which an SQL function executes is stored in an
3401** sqlite3_context object.  ^A pointer to an sqlite3_context object
3402** is always first parameter to [application-defined SQL functions].
3403** The application-defined SQL function implementation will pass this
3404** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
3405** [sqlite3_aggregate_context()], [sqlite3_user_data()],
3406** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
3407** and/or [sqlite3_set_auxdata()].
3408*/
3409typedef struct sqlite3_context sqlite3_context;
3410
3411/*
3412** CAPI3REF: Binding Values To Prepared Statements
3413** KEYWORDS: {host parameter} {host parameters} {host parameter name}
3414** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
3415**
3416** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
3417** literals may be replaced by a [parameter] that matches one of following
3418** templates:
3419**
3420** <ul>
3421** <li>  ?
3422** <li>  ?NNN
3423** <li>  :VVV
3424** <li>  @VVV
3425** <li>  $VVV
3426** </ul>
3427**
3428** In the templates above, NNN represents an integer literal,
3429** and VVV represents an alphanumeric identifier.)^  ^The values of these
3430** parameters (also called "host parameter names" or "SQL parameters")
3431** can be set using the sqlite3_bind_*() routines defined here.
3432**
3433** ^The first argument to the sqlite3_bind_*() routines is always
3434** a pointer to the [sqlite3_stmt] object returned from
3435** [sqlite3_prepare_v2()] or its variants.
3436**
3437** ^The second argument is the index of the SQL parameter to be set.
3438** ^The leftmost SQL parameter has an index of 1.  ^When the same named
3439** SQL parameter is used more than once, second and subsequent
3440** occurrences have the same index as the first occurrence.
3441** ^The index for named parameters can be looked up using the
3442** [sqlite3_bind_parameter_index()] API if desired.  ^The index
3443** for "?NNN" parameters is the value of NNN.
3444** ^The NNN value must be between 1 and the [sqlite3_limit()]
3445** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999).
3446**
3447** ^The third argument is the value to bind to the parameter.
3448** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16()
3449** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter
3450** is ignored and the end result is the same as sqlite3_bind_null().
3451**
3452** ^(In those routines that have a fourth argument, its value is the
3453** number of bytes in the parameter.  To be clear: the value is the
3454** number of <u>bytes</u> in the value, not the number of characters.)^
3455** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()
3456** is negative, then the length of the string is
3457** the number of bytes up to the first zero terminator.
3458** If the fourth parameter to sqlite3_bind_blob() is negative, then
3459** the behavior is undefined.
3460** If a non-negative fourth parameter is provided to sqlite3_bind_text()
3461** or sqlite3_bind_text16() or sqlite3_bind_text64() then
3462** that parameter must be the byte offset
3463** where the NUL terminator would occur assuming the string were NUL
3464** terminated.  If any NUL characters occur at byte offsets less than
3465** the value of the fourth parameter then the resulting string value will
3466** contain embedded NULs.  The result of expressions involving strings
3467** with embedded NULs is undefined.
3468**
3469** ^The fifth argument to the BLOB and string binding interfaces
3470** is a destructor used to dispose of the BLOB or
3471** string after SQLite has finished with it.  ^The destructor is called
3472** to dispose of the BLOB or string even if the call to bind API fails.
3473** ^If the fifth argument is
3474** the special value [SQLITE_STATIC], then SQLite assumes that the
3475** information is in static, unmanaged space and does not need to be freed.
3476** ^If the fifth argument has the value [SQLITE_TRANSIENT], then
3477** SQLite makes its own private copy of the data immediately, before
3478** the sqlite3_bind_*() routine returns.
3479**
3480** ^The sixth argument to sqlite3_bind_text64() must be one of
3481** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]
3482** to specify the encoding of the text in the third parameter.  If
3483** the sixth argument to sqlite3_bind_text64() is not one of the
3484** allowed values shown above, or if the text encoding is different
3485** from the encoding specified by the sixth parameter, then the behavior
3486** is undefined.
3487**
3488** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
3489** is filled with zeroes.  ^A zeroblob uses a fixed amount of memory
3490** (just an integer to hold its size) while it is being processed.
3491** Zeroblobs are intended to serve as placeholders for BLOBs whose
3492** content is later written using
3493** [sqlite3_blob_open | incremental BLOB I/O] routines.
3494** ^A negative value for the zeroblob results in a zero-length BLOB.
3495**
3496** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
3497** for the [prepared statement] or with a prepared statement for which
3498** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
3499** then the call will return [SQLITE_MISUSE].  If any sqlite3_bind_()
3500** routine is passed a [prepared statement] that has been finalized, the
3501** result is undefined and probably harmful.
3502**
3503** ^Bindings are not cleared by the [sqlite3_reset()] routine.
3504** ^Unbound parameters are interpreted as NULL.
3505**
3506** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
3507** [error code] if anything goes wrong.
3508** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB
3509** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or
3510** [SQLITE_MAX_LENGTH].
3511** ^[SQLITE_RANGE] is returned if the parameter
3512** index is out of range.  ^[SQLITE_NOMEM] is returned if malloc() fails.
3513**
3514** See also: [sqlite3_bind_parameter_count()],
3515** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
3516*/
3517SQLITE_API int SQLITE_STDCALL sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
3518SQLITE_API int SQLITE_STDCALL sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64,
3519                        void(*)(void*));
3520SQLITE_API int SQLITE_STDCALL sqlite3_bind_double(sqlite3_stmt*, int, double);
3521SQLITE_API int SQLITE_STDCALL sqlite3_bind_int(sqlite3_stmt*, int, int);
3522SQLITE_API int SQLITE_STDCALL sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
3523SQLITE_API int SQLITE_STDCALL sqlite3_bind_null(sqlite3_stmt*, int);
3524SQLITE_API int SQLITE_STDCALL sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*));
3525SQLITE_API int SQLITE_STDCALL sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
3526SQLITE_API int SQLITE_STDCALL sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64,
3527                         void(*)(void*), unsigned char encoding);
3528SQLITE_API int SQLITE_STDCALL sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
3529SQLITE_API int SQLITE_STDCALL sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
3530
3531/*
3532** CAPI3REF: Number Of SQL Parameters
3533**
3534** ^This routine can be used to find the number of [SQL parameters]
3535** in a [prepared statement].  SQL parameters are tokens of the
3536** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
3537** placeholders for values that are [sqlite3_bind_blob | bound]
3538** to the parameters at a later time.
3539**
3540** ^(This routine actually returns the index of the largest (rightmost)
3541** parameter. For all forms except ?NNN, this will correspond to the
3542** number of unique parameters.  If parameters of the ?NNN form are used,
3543** there may be gaps in the list.)^
3544**
3545** See also: [sqlite3_bind_blob|sqlite3_bind()],
3546** [sqlite3_bind_parameter_name()], and
3547** [sqlite3_bind_parameter_index()].
3548*/
3549SQLITE_API int SQLITE_STDCALL sqlite3_bind_parameter_count(sqlite3_stmt*);
3550
3551/*
3552** CAPI3REF: Name Of A Host Parameter
3553**
3554** ^The sqlite3_bind_parameter_name(P,N) interface returns
3555** the name of the N-th [SQL parameter] in the [prepared statement] P.
3556** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
3557** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
3558** respectively.
3559** In other words, the initial ":" or "$" or "@" or "?"
3560** is included as part of the name.)^
3561** ^Parameters of the form "?" without a following integer have no name
3562** and are referred to as "nameless" or "anonymous parameters".
3563**
3564** ^The first host parameter has an index of 1, not 0.
3565**
3566** ^If the value N is out of range or if the N-th parameter is
3567** nameless, then NULL is returned.  ^The returned string is
3568** always in UTF-8 encoding even if the named parameter was
3569** originally specified as UTF-16 in [sqlite3_prepare16()] or
3570** [sqlite3_prepare16_v2()].
3571**
3572** See also: [sqlite3_bind_blob|sqlite3_bind()],
3573** [sqlite3_bind_parameter_count()], and
3574** [sqlite3_bind_parameter_index()].
3575*/
3576SQLITE_API const char *SQLITE_STDCALL sqlite3_bind_parameter_name(sqlite3_stmt*, int);
3577
3578/*
3579** CAPI3REF: Index Of A Parameter With A Given Name
3580**
3581** ^Return the index of an SQL parameter given its name.  ^The
3582** index value returned is suitable for use as the second
3583** parameter to [sqlite3_bind_blob|sqlite3_bind()].  ^A zero
3584** is returned if no matching parameter is found.  ^The parameter
3585** name must be given in UTF-8 even if the original statement
3586** was prepared from UTF-16 text using [sqlite3_prepare16_v2()].
3587**
3588** See also: [sqlite3_bind_blob|sqlite3_bind()],
3589** [sqlite3_bind_parameter_count()], and
3590** [sqlite3_bind_parameter_index()].
3591*/
3592SQLITE_API int SQLITE_STDCALL sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
3593
3594/*
3595** CAPI3REF: Reset All Bindings On A Prepared Statement
3596**
3597** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
3598** the [sqlite3_bind_blob | bindings] on a [prepared statement].
3599** ^Use this routine to reset all host parameters to NULL.
3600*/
3601SQLITE_API int SQLITE_STDCALL sqlite3_clear_bindings(sqlite3_stmt*);
3602
3603/*
3604** CAPI3REF: Number Of Columns In A Result Set
3605**
3606** ^Return the number of columns in the result set returned by the
3607** [prepared statement]. ^This routine returns 0 if pStmt is an SQL
3608** statement that does not return data (for example an [UPDATE]).
3609**
3610** See also: [sqlite3_data_count()]
3611*/
3612SQLITE_API int SQLITE_STDCALL sqlite3_column_count(sqlite3_stmt *pStmt);
3613
3614/*
3615** CAPI3REF: Column Names In A Result Set
3616**
3617** ^These routines return the name assigned to a particular column
3618** in the result set of a [SELECT] statement.  ^The sqlite3_column_name()
3619** interface returns a pointer to a zero-terminated UTF-8 string
3620** and sqlite3_column_name16() returns a pointer to a zero-terminated
3621** UTF-16 string.  ^The first parameter is the [prepared statement]
3622** that implements the [SELECT] statement. ^The second parameter is the
3623** column number.  ^The leftmost column is number 0.
3624**
3625** ^The returned string pointer is valid until either the [prepared statement]
3626** is destroyed by [sqlite3_finalize()] or until the statement is automatically
3627** reprepared by the first call to [sqlite3_step()] for a particular run
3628** or until the next call to
3629** sqlite3_column_name() or sqlite3_column_name16() on the same column.
3630**
3631** ^If sqlite3_malloc() fails during the processing of either routine
3632** (for example during a conversion from UTF-8 to UTF-16) then a
3633** NULL pointer is returned.
3634**
3635** ^The name of a result column is the value of the "AS" clause for
3636** that column, if there is an AS clause.  If there is no AS clause
3637** then the name of the column is unspecified and may change from
3638** one release of SQLite to the next.
3639*/
3640SQLITE_API const char *SQLITE_STDCALL sqlite3_column_name(sqlite3_stmt*, int N);
3641SQLITE_API const void *SQLITE_STDCALL sqlite3_column_name16(sqlite3_stmt*, int N);
3642
3643/*
3644** CAPI3REF: Source Of Data In A Query Result
3645**
3646** ^These routines provide a means to determine the database, table, and
3647** table column that is the origin of a particular result column in
3648** [SELECT] statement.
3649** ^The name of the database or table or column can be returned as
3650** either a UTF-8 or UTF-16 string.  ^The _database_ routines return
3651** the database name, the _table_ routines return the table name, and
3652** the origin_ routines return the column name.
3653** ^The returned string is valid until the [prepared statement] is destroyed
3654** using [sqlite3_finalize()] or until the statement is automatically
3655** reprepared by the first call to [sqlite3_step()] for a particular run
3656** or until the same information is requested
3657** again in a different encoding.
3658**
3659** ^The names returned are the original un-aliased names of the
3660** database, table, and column.
3661**
3662** ^The first argument to these interfaces is a [prepared statement].
3663** ^These functions return information about the Nth result column returned by
3664** the statement, where N is the second function argument.
3665** ^The left-most column is column 0 for these routines.
3666**
3667** ^If the Nth column returned by the statement is an expression or
3668** subquery and is not a column value, then all of these functions return
3669** NULL.  ^These routine might also return NULL if a memory allocation error
3670** occurs.  ^Otherwise, they return the name of the attached database, table,
3671** or column that query result column was extracted from.
3672**
3673** ^As with all other SQLite APIs, those whose names end with "16" return
3674** UTF-16 encoded strings and the other functions return UTF-8.
3675**
3676** ^These APIs are only available if the library was compiled with the
3677** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
3678**
3679** If two or more threads call one or more of these routines against the same
3680** prepared statement and column at the same time then the results are
3681** undefined.
3682**
3683** If two or more threads call one or more
3684** [sqlite3_column_database_name | column metadata interfaces]
3685** for the same [prepared statement] and result column
3686** at the same time then the results are undefined.
3687*/
3688SQLITE_API const char *SQLITE_STDCALL sqlite3_column_database_name(sqlite3_stmt*,int);
3689SQLITE_API const void *SQLITE_STDCALL sqlite3_column_database_name16(sqlite3_stmt*,int);
3690SQLITE_API const char *SQLITE_STDCALL sqlite3_column_table_name(sqlite3_stmt*,int);
3691SQLITE_API const void *SQLITE_STDCALL sqlite3_column_table_name16(sqlite3_stmt*,int);
3692SQLITE_API const char *SQLITE_STDCALL sqlite3_column_origin_name(sqlite3_stmt*,int);
3693SQLITE_API const void *SQLITE_STDCALL sqlite3_column_origin_name16(sqlite3_stmt*,int);
3694
3695/*
3696** CAPI3REF: Declared Datatype Of A Query Result
3697**
3698** ^(The first parameter is a [prepared statement].
3699** If this statement is a [SELECT] statement and the Nth column of the
3700** returned result set of that [SELECT] is a table column (not an
3701** expression or subquery) then the declared type of the table
3702** column is returned.)^  ^If the Nth column of the result set is an
3703** expression or subquery, then a NULL pointer is returned.
3704** ^The returned string is always UTF-8 encoded.
3705**
3706** ^(For example, given the database schema:
3707**
3708** CREATE TABLE t1(c1 VARIANT);
3709**
3710** and the following statement to be compiled:
3711**
3712** SELECT c1 + 1, c1 FROM t1;
3713**
3714** this routine would return the string "VARIANT" for the second result
3715** column (i==1), and a NULL pointer for the first result column (i==0).)^
3716**
3717** ^SQLite uses dynamic run-time typing.  ^So just because a column
3718** is declared to contain a particular type does not mean that the
3719** data stored in that column is of the declared type.  SQLite is
3720** strongly typed, but the typing is dynamic not static.  ^Type
3721** is associated with individual values, not with the containers
3722** used to hold those values.
3723*/
3724SQLITE_API const char *SQLITE_STDCALL sqlite3_column_decltype(sqlite3_stmt*,int);
3725SQLITE_API const void *SQLITE_STDCALL sqlite3_column_decltype16(sqlite3_stmt*,int);
3726
3727/*
3728** CAPI3REF: Evaluate An SQL Statement
3729**
3730** After a [prepared statement] has been prepared using either
3731** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy
3732** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
3733** must be called one or more times to evaluate the statement.
3734**
3735** The details of the behavior of the sqlite3_step() interface depend
3736** on whether the statement was prepared using the newer "v2" interface
3737** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy
3738** interface [sqlite3_prepare()] and [sqlite3_prepare16()].  The use of the
3739** new "v2" interface is recommended for new applications but the legacy
3740** interface will continue to be supported.
3741**
3742** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
3743** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
3744** ^With the "v2" interface, any of the other [result codes] or
3745** [extended result codes] might be returned as well.
3746**
3747** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
3748** database locks it needs to do its job.  ^If the statement is a [COMMIT]
3749** or occurs outside of an explicit transaction, then you can retry the
3750** statement.  If the statement is not a [COMMIT] and occurs within an
3751** explicit transaction then you should rollback the transaction before
3752** continuing.
3753**
3754** ^[SQLITE_DONE] means that the statement has finished executing
3755** successfully.  sqlite3_step() should not be called again on this virtual
3756** machine without first calling [sqlite3_reset()] to reset the virtual
3757** machine back to its initial state.
3758**
3759** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
3760** is returned each time a new row of data is ready for processing by the
3761** caller. The values may be accessed using the [column access functions].
3762** sqlite3_step() is called again to retrieve the next row of data.
3763**
3764** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
3765** violation) has occurred.  sqlite3_step() should not be called again on
3766** the VM. More information may be found by calling [sqlite3_errmsg()].
3767** ^With the legacy interface, a more specific error code (for example,
3768** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
3769** can be obtained by calling [sqlite3_reset()] on the
3770** [prepared statement].  ^In the "v2" interface,
3771** the more specific error code is returned directly by sqlite3_step().
3772**
3773** [SQLITE_MISUSE] means that the this routine was called inappropriately.
3774** Perhaps it was called on a [prepared statement] that has
3775** already been [sqlite3_finalize | finalized] or on one that had
3776** previously returned [SQLITE_ERROR] or [SQLITE_DONE].  Or it could
3777** be the case that the same database connection is being used by two or
3778** more threads at the same moment in time.
3779**
3780** For all versions of SQLite up to and including 3.6.23.1, a call to
3781** [sqlite3_reset()] was required after sqlite3_step() returned anything
3782** other than [SQLITE_ROW] before any subsequent invocation of
3783** sqlite3_step().  Failure to reset the prepared statement using
3784** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
3785** sqlite3_step().  But after version 3.6.23.1, sqlite3_step() began
3786** calling [sqlite3_reset()] automatically in this circumstance rather
3787** than returning [SQLITE_MISUSE].  This is not considered a compatibility
3788** break because any application that ever receives an SQLITE_MISUSE error
3789** is broken by definition.  The [SQLITE_OMIT_AUTORESET] compile-time option
3790** can be used to restore the legacy behavior.
3791**
3792** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
3793** API always returns a generic error code, [SQLITE_ERROR], following any
3794** error other than [SQLITE_BUSY] and [SQLITE_MISUSE].  You must call
3795** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
3796** specific [error codes] that better describes the error.
3797** We admit that this is a goofy design.  The problem has been fixed
3798** with the "v2" interface.  If you prepare all of your SQL statements
3799** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead
3800** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
3801** then the more specific [error codes] are returned directly
3802** by sqlite3_step().  The use of the "v2" interface is recommended.
3803*/
3804SQLITE_API int SQLITE_STDCALL sqlite3_step(sqlite3_stmt*);
3805
3806/*
3807** CAPI3REF: Number of columns in a result set
3808**
3809** ^The sqlite3_data_count(P) interface returns the number of columns in the
3810** current row of the result set of [prepared statement] P.
3811** ^If prepared statement P does not have results ready to return
3812** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of
3813** interfaces) then sqlite3_data_count(P) returns 0.
3814** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
3815** ^The sqlite3_data_count(P) routine returns 0 if the previous call to
3816** [sqlite3_step](P) returned [SQLITE_DONE].  ^The sqlite3_data_count(P)
3817** will return non-zero if previous call to [sqlite3_step](P) returned
3818** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum]
3819** where it always returns zero since each step of that multi-step
3820** pragma returns 0 columns of data.
3821**
3822** See also: [sqlite3_column_count()]
3823*/
3824SQLITE_API int SQLITE_STDCALL sqlite3_data_count(sqlite3_stmt *pStmt);
3825
3826/*
3827** CAPI3REF: Fundamental Datatypes
3828** KEYWORDS: SQLITE_TEXT
3829**
3830** ^(Every value in SQLite has one of five fundamental datatypes:
3831**
3832** <ul>
3833** <li> 64-bit signed integer
3834** <li> 64-bit IEEE floating point number
3835** <li> string
3836** <li> BLOB
3837** <li> NULL
3838** </ul>)^
3839**
3840** These constants are codes for each of those types.
3841**
3842** Note that the SQLITE_TEXT constant was also used in SQLite version 2
3843** for a completely different meaning.  Software that links against both
3844** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
3845** SQLITE_TEXT.
3846*/
3847#define SQLITE_INTEGER  1
3848#define SQLITE_FLOAT    2
3849#define SQLITE_BLOB     4
3850#define SQLITE_NULL     5
3851#ifdef SQLITE_TEXT
3852# undef SQLITE_TEXT
3853#else
3854# define SQLITE_TEXT     3
3855#endif
3856#define SQLITE3_TEXT     3
3857
3858/*
3859** CAPI3REF: Result Values From A Query
3860** KEYWORDS: {column access functions}
3861**
3862** These routines form the "result set" interface.
3863**
3864** ^These routines return information about a single column of the current
3865** result row of a query.  ^In every case the first argument is a pointer
3866** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
3867** that was returned from [sqlite3_prepare_v2()] or one of its variants)
3868** and the second argument is the index of the column for which information
3869** should be returned. ^The leftmost column of the result set has the index 0.
3870** ^The number of columns in the result can be determined using
3871** [sqlite3_column_count()].
3872**
3873** If the SQL statement does not currently point to a valid row, or if the
3874** column index is out of range, the result is undefined.
3875** These routines may only be called when the most recent call to
3876** [sqlite3_step()] has returned [SQLITE_ROW] and neither
3877** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
3878** If any of these routines are called after [sqlite3_reset()] or
3879** [sqlite3_finalize()] or after [sqlite3_step()] has returned
3880** something other than [SQLITE_ROW], the results are undefined.
3881** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
3882** are called from a different thread while any of these routines
3883** are pending, then the results are undefined.
3884**
3885** ^The sqlite3_column_type() routine returns the
3886** [SQLITE_INTEGER | datatype code] for the initial data type
3887** of the result column.  ^The returned value is one of [SQLITE_INTEGER],
3888** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].  The value
3889** returned by sqlite3_column_type() is only meaningful if no type
3890** conversions have occurred as described below.  After a type conversion,
3891** the value returned by sqlite3_column_type() is undefined.  Future
3892** versions of SQLite may change the behavior of sqlite3_column_type()
3893** following a type conversion.
3894**
3895** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
3896** routine returns the number of bytes in that BLOB or string.
3897** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
3898** the string to UTF-8 and then returns the number of bytes.
3899** ^If the result is a numeric value then sqlite3_column_bytes() uses
3900** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
3901** the number of bytes in that string.
3902** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
3903**
3904** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
3905** routine returns the number of bytes in that BLOB or string.
3906** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
3907** the string to UTF-16 and then returns the number of bytes.
3908** ^If the result is a numeric value then sqlite3_column_bytes16() uses
3909** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
3910** the number of bytes in that string.
3911** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
3912**
3913** ^The values returned by [sqlite3_column_bytes()] and
3914** [sqlite3_column_bytes16()] do not include the zero terminators at the end
3915** of the string.  ^For clarity: the values returned by
3916** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
3917** bytes in the string, not the number of characters.
3918**
3919** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
3920** even empty strings, are always zero-terminated.  ^The return
3921** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
3922**
3923** ^The object returned by [sqlite3_column_value()] is an
3924** [unprotected sqlite3_value] object.  An unprotected sqlite3_value object
3925** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()].
3926** If the [unprotected sqlite3_value] object returned by
3927** [sqlite3_column_value()] is used in any other way, including calls
3928** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
3929** or [sqlite3_value_bytes()], then the behavior is undefined.
3930**
3931** These routines attempt to convert the value where appropriate.  ^For
3932** example, if the internal representation is FLOAT and a text result
3933** is requested, [sqlite3_snprintf()] is used internally to perform the
3934** conversion automatically.  ^(The following table details the conversions
3935** that are applied:
3936**
3937** <blockquote>
3938** <table border="1">
3939** <tr><th> Internal<br>Type <th> Requested<br>Type <th>  Conversion
3940**
3941** <tr><td>  NULL    <td> INTEGER   <td> Result is 0
3942** <tr><td>  NULL    <td>  FLOAT    <td> Result is 0.0
3943** <tr><td>  NULL    <td>   TEXT    <td> Result is a NULL pointer
3944** <tr><td>  NULL    <td>   BLOB    <td> Result is a NULL pointer
3945** <tr><td> INTEGER  <td>  FLOAT    <td> Convert from integer to float
3946** <tr><td> INTEGER  <td>   TEXT    <td> ASCII rendering of the integer
3947** <tr><td> INTEGER  <td>   BLOB    <td> Same as INTEGER->TEXT
3948** <tr><td>  FLOAT   <td> INTEGER   <td> [CAST] to INTEGER
3949** <tr><td>  FLOAT   <td>   TEXT    <td> ASCII rendering of the float
3950** <tr><td>  FLOAT   <td>   BLOB    <td> [CAST] to BLOB
3951** <tr><td>  TEXT    <td> INTEGER   <td> [CAST] to INTEGER
3952** <tr><td>  TEXT    <td>  FLOAT    <td> [CAST] to REAL
3953** <tr><td>  TEXT    <td>   BLOB    <td> No change
3954** <tr><td>  BLOB    <td> INTEGER   <td> [CAST] to INTEGER
3955** <tr><td>  BLOB    <td>  FLOAT    <td> [CAST] to REAL
3956** <tr><td>  BLOB    <td>   TEXT    <td> Add a zero terminator if needed
3957** </table>
3958** </blockquote>)^
3959**
3960** The table above makes reference to standard C library functions atoi()
3961** and atof().  SQLite does not really use these functions.  It has its
3962** own equivalent internal routines.  The atoi() and atof() names are
3963** used in the table for brevity and because they are familiar to most
3964** C programmers.
3965**
3966** Note that when type conversions occur, pointers returned by prior
3967** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
3968** sqlite3_column_text16() may be invalidated.
3969** Type conversions and pointer invalidations might occur
3970** in the following cases:
3971**
3972** <ul>
3973** <li> The initial content is a BLOB and sqlite3_column_text() or
3974**      sqlite3_column_text16() is called.  A zero-terminator might
3975**      need to be added to the string.</li>
3976** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
3977**      sqlite3_column_text16() is called.  The content must be converted
3978**      to UTF-16.</li>
3979** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
3980**      sqlite3_column_text() is called.  The content must be converted
3981**      to UTF-8.</li>
3982** </ul>
3983**
3984** ^Conversions between UTF-16be and UTF-16le are always done in place and do
3985** not invalidate a prior pointer, though of course the content of the buffer
3986** that the prior pointer references will have been modified.  Other kinds
3987** of conversion are done in place when it is possible, but sometimes they
3988** are not possible and in those cases prior pointers are invalidated.
3989**
3990** The safest and easiest to remember policy is to invoke these routines
3991** in one of the following ways:
3992**
3993** <ul>
3994**  <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
3995**  <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
3996**  <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
3997** </ul>
3998**
3999** In other words, you should call sqlite3_column_text(),
4000** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
4001** into the desired format, then invoke sqlite3_column_bytes() or
4002** sqlite3_column_bytes16() to find the size of the result.  Do not mix calls
4003** to sqlite3_column_text() or sqlite3_column_blob() with calls to
4004** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
4005** with calls to sqlite3_column_bytes().
4006**
4007** ^The pointers returned are valid until a type conversion occurs as
4008** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
4009** [sqlite3_finalize()] is called.  ^The memory space used to hold strings
4010** and BLOBs is freed automatically.  Do <b>not</b> pass the pointers returned
4011** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
4012** [sqlite3_free()].
4013**
4014** ^(If a memory allocation error occurs during the evaluation of any
4015** of these routines, a default value is returned.  The default value
4016** is either the integer 0, the floating point number 0.0, or a NULL
4017** pointer.  Subsequent calls to [sqlite3_errcode()] will return
4018** [SQLITE_NOMEM].)^
4019*/
4020SQLITE_API const void *SQLITE_STDCALL sqlite3_column_blob(sqlite3_stmt*, int iCol);
4021SQLITE_API int SQLITE_STDCALL sqlite3_column_bytes(sqlite3_stmt*, int iCol);
4022SQLITE_API int SQLITE_STDCALL sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
4023SQLITE_API double SQLITE_STDCALL sqlite3_column_double(sqlite3_stmt*, int iCol);
4024SQLITE_API int SQLITE_STDCALL sqlite3_column_int(sqlite3_stmt*, int iCol);
4025SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_column_int64(sqlite3_stmt*, int iCol);
4026SQLITE_API const unsigned char *SQLITE_STDCALL sqlite3_column_text(sqlite3_stmt*, int iCol);
4027SQLITE_API const void *SQLITE_STDCALL sqlite3_column_text16(sqlite3_stmt*, int iCol);
4028SQLITE_API int SQLITE_STDCALL sqlite3_column_type(sqlite3_stmt*, int iCol);
4029SQLITE_API sqlite3_value *SQLITE_STDCALL sqlite3_column_value(sqlite3_stmt*, int iCol);
4030
4031/*
4032** CAPI3REF: Destroy A Prepared Statement Object
4033**
4034** ^The sqlite3_finalize() function is called to delete a [prepared statement].
4035** ^If the most recent evaluation of the statement encountered no errors
4036** or if the statement is never been evaluated, then sqlite3_finalize() returns
4037** SQLITE_OK.  ^If the most recent evaluation of statement S failed, then
4038** sqlite3_finalize(S) returns the appropriate [error code] or
4039** [extended error code].
4040**
4041** ^The sqlite3_finalize(S) routine can be called at any point during
4042** the life cycle of [prepared statement] S:
4043** before statement S is ever evaluated, after
4044** one or more calls to [sqlite3_reset()], or after any call
4045** to [sqlite3_step()] regardless of whether or not the statement has
4046** completed execution.
4047**
4048** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
4049**
4050** The application must finalize every [prepared statement] in order to avoid
4051** resource leaks.  It is a grievous error for the application to try to use
4052** a prepared statement after it has been finalized.  Any use of a prepared
4053** statement after it has been finalized can result in undefined and
4054** undesirable behavior such as segfaults and heap corruption.
4055*/
4056SQLITE_API int SQLITE_STDCALL sqlite3_finalize(sqlite3_stmt *pStmt);
4057
4058/*
4059** CAPI3REF: Reset A Prepared Statement Object
4060**
4061** The sqlite3_reset() function is called to reset a [prepared statement]
4062** object back to its initial state, ready to be re-executed.
4063** ^Any SQL statement variables that had values bound to them using
4064** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
4065** Use [sqlite3_clear_bindings()] to reset the bindings.
4066**
4067** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
4068** back to the beginning of its program.
4069**
4070** ^If the most recent call to [sqlite3_step(S)] for the
4071** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
4072** or if [sqlite3_step(S)] has never before been called on S,
4073** then [sqlite3_reset(S)] returns [SQLITE_OK].
4074**
4075** ^If the most recent call to [sqlite3_step(S)] for the
4076** [prepared statement] S indicated an error, then
4077** [sqlite3_reset(S)] returns an appropriate [error code].
4078**
4079** ^The [sqlite3_reset(S)] interface does not change the values
4080** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
4081*/
4082SQLITE_API int SQLITE_STDCALL sqlite3_reset(sqlite3_stmt *pStmt);
4083
4084/*
4085** CAPI3REF: Create Or Redefine SQL Functions
4086** KEYWORDS: {function creation routines}
4087** KEYWORDS: {application-defined SQL function}
4088** KEYWORDS: {application-defined SQL functions}
4089**
4090** ^These functions (collectively known as "function creation routines")
4091** are used to add SQL functions or aggregates or to redefine the behavior
4092** of existing SQL functions or aggregates.  The only differences between
4093** these routines are the text encoding expected for
4094** the second parameter (the name of the function being created)
4095** and the presence or absence of a destructor callback for
4096** the application data pointer.
4097**
4098** ^The first parameter is the [database connection] to which the SQL
4099** function is to be added.  ^If an application uses more than one database
4100** connection then application-defined SQL functions must be added
4101** to each database connection separately.
4102**
4103** ^The second parameter is the name of the SQL function to be created or
4104** redefined.  ^The length of the name is limited to 255 bytes in a UTF-8
4105** representation, exclusive of the zero-terminator.  ^Note that the name
4106** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
4107** ^Any attempt to create a function with a longer name
4108** will result in [SQLITE_MISUSE] being returned.
4109**
4110** ^The third parameter (nArg)
4111** is the number of arguments that the SQL function or
4112** aggregate takes. ^If this parameter is -1, then the SQL function or
4113** aggregate may take any number of arguments between 0 and the limit
4114** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]).  If the third
4115** parameter is less than -1 or greater than 127 then the behavior is
4116** undefined.
4117**
4118** ^The fourth parameter, eTextRep, specifies what
4119** [SQLITE_UTF8 | text encoding] this SQL function prefers for
4120** its parameters.  The application should set this parameter to
4121** [SQLITE_UTF16LE] if the function implementation invokes
4122** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the
4123** implementation invokes [sqlite3_value_text16be()] on an input, or
4124** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8]
4125** otherwise.  ^The same SQL function may be registered multiple times using
4126** different preferred text encodings, with different implementations for
4127** each encoding.
4128** ^When multiple implementations of the same function are available, SQLite
4129** will pick the one that involves the least amount of data conversion.
4130**
4131** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC]
4132** to signal that the function will always return the same result given
4133** the same inputs within a single SQL statement.  Most SQL functions are
4134** deterministic.  The built-in [random()] SQL function is an example of a
4135** function that is not deterministic.  The SQLite query planner is able to
4136** perform additional optimizations on deterministic functions, so use
4137** of the [SQLITE_DETERMINISTIC] flag is recommended where possible.
4138**
4139** ^(The fifth parameter is an arbitrary pointer.  The implementation of the
4140** function can gain access to this pointer using [sqlite3_user_data()].)^
4141**
4142** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are
4143** pointers to C-language functions that implement the SQL function or
4144** aggregate. ^A scalar SQL function requires an implementation of the xFunc
4145** callback only; NULL pointers must be passed as the xStep and xFinal
4146** parameters. ^An aggregate SQL function requires an implementation of xStep
4147** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
4148** SQL function or aggregate, pass NULL pointers for all three function
4149** callbacks.
4150**
4151** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL,
4152** then it is destructor for the application data pointer.
4153** The destructor is invoked when the function is deleted, either by being
4154** overloaded or when the database connection closes.)^
4155** ^The destructor is also invoked if the call to
4156** sqlite3_create_function_v2() fails.
4157** ^When the destructor callback of the tenth parameter is invoked, it
4158** is passed a single argument which is a copy of the application data
4159** pointer which was the fifth parameter to sqlite3_create_function_v2().
4160**
4161** ^It is permitted to register multiple implementations of the same
4162** functions with the same name but with either differing numbers of
4163** arguments or differing preferred text encodings.  ^SQLite will use
4164** the implementation that most closely matches the way in which the
4165** SQL function is used.  ^A function implementation with a non-negative
4166** nArg parameter is a better match than a function implementation with
4167** a negative nArg.  ^A function where the preferred text encoding
4168** matches the database encoding is a better
4169** match than a function where the encoding is different.
4170** ^A function where the encoding difference is between UTF16le and UTF16be
4171** is a closer match than a function where the encoding difference is
4172** between UTF8 and UTF16.
4173**
4174** ^Built-in functions may be overloaded by new application-defined functions.
4175**
4176** ^An application-defined function is permitted to call other
4177** SQLite interfaces.  However, such calls must not
4178** close the database connection nor finalize or reset the prepared
4179** statement in which the function is running.
4180*/
4181SQLITE_API int SQLITE_STDCALL sqlite3_create_function(
4182  sqlite3 *db,
4183  const char *zFunctionName,
4184  int nArg,
4185  int eTextRep,
4186  void *pApp,
4187  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4188  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4189  void (*xFinal)(sqlite3_context*)
4190);
4191SQLITE_API int SQLITE_STDCALL sqlite3_create_function16(
4192  sqlite3 *db,
4193  const void *zFunctionName,
4194  int nArg,
4195  int eTextRep,
4196  void *pApp,
4197  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4198  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4199  void (*xFinal)(sqlite3_context*)
4200);
4201SQLITE_API int SQLITE_STDCALL sqlite3_create_function_v2(
4202  sqlite3 *db,
4203  const char *zFunctionName,
4204  int nArg,
4205  int eTextRep,
4206  void *pApp,
4207  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4208  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4209  void (*xFinal)(sqlite3_context*),
4210  void(*xDestroy)(void*)
4211);
4212
4213/*
4214** CAPI3REF: Text Encodings
4215**
4216** These constant define integer codes that represent the various
4217** text encodings supported by SQLite.
4218*/
4219#define SQLITE_UTF8           1    /* IMP: R-37514-35566 */
4220#define SQLITE_UTF16LE        2    /* IMP: R-03371-37637 */
4221#define SQLITE_UTF16BE        3    /* IMP: R-51971-34154 */
4222#define SQLITE_UTF16          4    /* Use native byte order */
4223#define SQLITE_ANY            5    /* Deprecated */
4224#define SQLITE_UTF16_ALIGNED  8    /* sqlite3_create_collation only */
4225
4226/*
4227** CAPI3REF: Function Flags
4228**
4229** These constants may be ORed together with the
4230** [SQLITE_UTF8 | preferred text encoding] as the fourth argument
4231** to [sqlite3_create_function()], [sqlite3_create_function16()], or
4232** [sqlite3_create_function_v2()].
4233*/
4234#define SQLITE_DETERMINISTIC    0x800
4235
4236/*
4237** CAPI3REF: Deprecated Functions
4238** DEPRECATED
4239**
4240** These functions are [deprecated].  In order to maintain
4241** backwards compatibility with older code, these functions continue
4242** to be supported.  However, new applications should avoid
4243** the use of these functions.  To encourage programmers to avoid
4244** these functions, we will not explain what they do.
4245*/
4246#ifndef SQLITE_OMIT_DEPRECATED
4247SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_aggregate_count(sqlite3_context*);
4248SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_expired(sqlite3_stmt*);
4249SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
4250SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_global_recover(void);
4251SQLITE_API SQLITE_DEPRECATED void SQLITE_STDCALL sqlite3_thread_cleanup(void);
4252SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),
4253                      void*,sqlite3_int64);
4254#endif
4255
4256/*
4257** CAPI3REF: Obtaining SQL Function Parameter Values
4258**
4259** The C-language implementation of SQL functions and aggregates uses
4260** this set of interface routines to access the parameter values on
4261** the function or aggregate.
4262**
4263** The xFunc (for scalar functions) or xStep (for aggregates) parameters
4264** to [sqlite3_create_function()] and [sqlite3_create_function16()]
4265** define callbacks that implement the SQL functions and aggregates.
4266** The 3rd parameter to these callbacks is an array of pointers to
4267** [protected sqlite3_value] objects.  There is one [sqlite3_value] object for
4268** each parameter to the SQL function.  These routines are used to
4269** extract values from the [sqlite3_value] objects.
4270**
4271** These routines work only with [protected sqlite3_value] objects.
4272** Any attempt to use these routines on an [unprotected sqlite3_value]
4273** object results in undefined behavior.
4274**
4275** ^These routines work just like the corresponding [column access functions]
4276** except that these routines take a single [protected sqlite3_value] object
4277** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
4278**
4279** ^The sqlite3_value_text16() interface extracts a UTF-16 string
4280** in the native byte-order of the host machine.  ^The
4281** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
4282** extract UTF-16 strings as big-endian and little-endian respectively.
4283**
4284** ^(The sqlite3_value_numeric_type() interface attempts to apply
4285** numeric affinity to the value.  This means that an attempt is
4286** made to convert the value to an integer or floating point.  If
4287** such a conversion is possible without loss of information (in other
4288** words, if the value is a string that looks like a number)
4289** then the conversion is performed.  Otherwise no conversion occurs.
4290** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
4291**
4292** Please pay particular attention to the fact that the pointer returned
4293** from [sqlite3_value_blob()], [sqlite3_value_text()], or
4294** [sqlite3_value_text16()] can be invalidated by a subsequent call to
4295** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
4296** or [sqlite3_value_text16()].
4297**
4298** These routines must be called from the same thread as
4299** the SQL function that supplied the [sqlite3_value*] parameters.
4300*/
4301SQLITE_API const void *SQLITE_STDCALL sqlite3_value_blob(sqlite3_value*);
4302SQLITE_API int SQLITE_STDCALL sqlite3_value_bytes(sqlite3_value*);
4303SQLITE_API int SQLITE_STDCALL sqlite3_value_bytes16(sqlite3_value*);
4304SQLITE_API double SQLITE_STDCALL sqlite3_value_double(sqlite3_value*);
4305SQLITE_API int SQLITE_STDCALL sqlite3_value_int(sqlite3_value*);
4306SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_value_int64(sqlite3_value*);
4307SQLITE_API const unsigned char *SQLITE_STDCALL sqlite3_value_text(sqlite3_value*);
4308SQLITE_API const void *SQLITE_STDCALL sqlite3_value_text16(sqlite3_value*);
4309SQLITE_API const void *SQLITE_STDCALL sqlite3_value_text16le(sqlite3_value*);
4310SQLITE_API const void *SQLITE_STDCALL sqlite3_value_text16be(sqlite3_value*);
4311SQLITE_API int SQLITE_STDCALL sqlite3_value_type(sqlite3_value*);
4312SQLITE_API int SQLITE_STDCALL sqlite3_value_numeric_type(sqlite3_value*);
4313
4314/*
4315** CAPI3REF: Obtain Aggregate Function Context
4316**
4317** Implementations of aggregate SQL functions use this
4318** routine to allocate memory for storing their state.
4319**
4320** ^The first time the sqlite3_aggregate_context(C,N) routine is called
4321** for a particular aggregate function, SQLite
4322** allocates N of memory, zeroes out that memory, and returns a pointer
4323** to the new memory. ^On second and subsequent calls to
4324** sqlite3_aggregate_context() for the same aggregate function instance,
4325** the same buffer is returned.  Sqlite3_aggregate_context() is normally
4326** called once for each invocation of the xStep callback and then one
4327** last time when the xFinal callback is invoked.  ^(When no rows match
4328** an aggregate query, the xStep() callback of the aggregate function
4329** implementation is never called and xFinal() is called exactly once.
4330** In those cases, sqlite3_aggregate_context() might be called for the
4331** first time from within xFinal().)^
4332**
4333** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer
4334** when first called if N is less than or equal to zero or if a memory
4335** allocate error occurs.
4336**
4337** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
4338** determined by the N parameter on first successful call.  Changing the
4339** value of N in subsequent call to sqlite3_aggregate_context() within
4340** the same aggregate function instance will not resize the memory
4341** allocation.)^  Within the xFinal callback, it is customary to set
4342** N=0 in calls to sqlite3_aggregate_context(C,N) so that no
4343** pointless memory allocations occur.
4344**
4345** ^SQLite automatically frees the memory allocated by
4346** sqlite3_aggregate_context() when the aggregate query concludes.
4347**
4348** The first parameter must be a copy of the
4349** [sqlite3_context | SQL function context] that is the first parameter
4350** to the xStep or xFinal callback routine that implements the aggregate
4351** function.
4352**
4353** This routine must be called from the same thread in which
4354** the aggregate SQL function is running.
4355*/
4356SQLITE_API void *SQLITE_STDCALL sqlite3_aggregate_context(sqlite3_context*, int nBytes);
4357
4358/*
4359** CAPI3REF: User Data For Functions
4360**
4361** ^The sqlite3_user_data() interface returns a copy of
4362** the pointer that was the pUserData parameter (the 5th parameter)
4363** of the [sqlite3_create_function()]
4364** and [sqlite3_create_function16()] routines that originally
4365** registered the application defined function.
4366**
4367** This routine must be called from the same thread in which
4368** the application-defined function is running.
4369*/
4370SQLITE_API void *SQLITE_STDCALL sqlite3_user_data(sqlite3_context*);
4371
4372/*
4373** CAPI3REF: Database Connection For Functions
4374**
4375** ^The sqlite3_context_db_handle() interface returns a copy of
4376** the pointer to the [database connection] (the 1st parameter)
4377** of the [sqlite3_create_function()]
4378** and [sqlite3_create_function16()] routines that originally
4379** registered the application defined function.
4380*/
4381SQLITE_API sqlite3 *SQLITE_STDCALL sqlite3_context_db_handle(sqlite3_context*);
4382
4383/*
4384** CAPI3REF: Function Auxiliary Data
4385**
4386** These functions may be used by (non-aggregate) SQL functions to
4387** associate metadata with argument values. If the same value is passed to
4388** multiple invocations of the same SQL function during query execution, under
4389** some circumstances the associated metadata may be preserved.  An example
4390** of where this might be useful is in a regular-expression matching
4391** function. The compiled version of the regular expression can be stored as
4392** metadata associated with the pattern string.
4393** Then as long as the pattern string remains the same,
4394** the compiled regular expression can be reused on multiple
4395** invocations of the same function.
4396**
4397** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata
4398** associated by the sqlite3_set_auxdata() function with the Nth argument
4399** value to the application-defined function. ^If there is no metadata
4400** associated with the function argument, this sqlite3_get_auxdata() interface
4401** returns a NULL pointer.
4402**
4403** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th
4404** argument of the application-defined function.  ^Subsequent
4405** calls to sqlite3_get_auxdata(C,N) return P from the most recent
4406** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or
4407** NULL if the metadata has been discarded.
4408** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL,
4409** SQLite will invoke the destructor function X with parameter P exactly
4410** once, when the metadata is discarded.
4411** SQLite is free to discard the metadata at any time, including: <ul>
4412** <li> when the corresponding function parameter changes, or
4413** <li> when [sqlite3_reset()] or [sqlite3_finalize()] is called for the
4414**      SQL statement, or
4415** <li> when sqlite3_set_auxdata() is invoked again on the same parameter, or
4416** <li> during the original sqlite3_set_auxdata() call when a memory
4417**      allocation error occurs. </ul>)^
4418**
4419** Note the last bullet in particular.  The destructor X in
4420** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the
4421** sqlite3_set_auxdata() interface even returns.  Hence sqlite3_set_auxdata()
4422** should be called near the end of the function implementation and the
4423** function implementation should not make any use of P after
4424** sqlite3_set_auxdata() has been called.
4425**
4426** ^(In practice, metadata is preserved between function calls for
4427** function parameters that are compile-time constants, including literal
4428** values and [parameters] and expressions composed from the same.)^
4429**
4430** These routines must be called from the same thread in which
4431** the SQL function is running.
4432*/
4433SQLITE_API void *SQLITE_STDCALL sqlite3_get_auxdata(sqlite3_context*, int N);
4434SQLITE_API void SQLITE_STDCALL sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
4435
4436
4437/*
4438** CAPI3REF: Constants Defining Special Destructor Behavior
4439**
4440** These are special values for the destructor that is passed in as the
4441** final argument to routines like [sqlite3_result_blob()].  ^If the destructor
4442** argument is SQLITE_STATIC, it means that the content pointer is constant
4443** and will never change.  It does not need to be destroyed.  ^The
4444** SQLITE_TRANSIENT value means that the content will likely change in
4445** the near future and that SQLite should make its own private copy of
4446** the content before returning.
4447**
4448** The typedef is necessary to work around problems in certain
4449** C++ compilers.
4450*/
4451typedef void (*sqlite3_destructor_type)(void*);
4452#define SQLITE_STATIC      ((sqlite3_destructor_type)0)
4453#define SQLITE_TRANSIENT   ((sqlite3_destructor_type)-1)
4454
4455/*
4456** CAPI3REF: Setting The Result Of An SQL Function
4457**
4458** These routines are used by the xFunc or xFinal callbacks that
4459** implement SQL functions and aggregates.  See
4460** [sqlite3_create_function()] and [sqlite3_create_function16()]
4461** for additional information.
4462**
4463** These functions work very much like the [parameter binding] family of
4464** functions used to bind values to host parameters in prepared statements.
4465** Refer to the [SQL parameter] documentation for additional information.
4466**
4467** ^The sqlite3_result_blob() interface sets the result from
4468** an application-defined function to be the BLOB whose content is pointed
4469** to by the second parameter and which is N bytes long where N is the
4470** third parameter.
4471**
4472** ^The sqlite3_result_zeroblob() interfaces set the result of
4473** the application-defined function to be a BLOB containing all zero
4474** bytes and N bytes in size, where N is the value of the 2nd parameter.
4475**
4476** ^The sqlite3_result_double() interface sets the result from
4477** an application-defined function to be a floating point value specified
4478** by its 2nd argument.
4479**
4480** ^The sqlite3_result_error() and sqlite3_result_error16() functions
4481** cause the implemented SQL function to throw an exception.
4482** ^SQLite uses the string pointed to by the
4483** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
4484** as the text of an error message.  ^SQLite interprets the error
4485** message string from sqlite3_result_error() as UTF-8. ^SQLite
4486** interprets the string from sqlite3_result_error16() as UTF-16 in native
4487** byte order.  ^If the third parameter to sqlite3_result_error()
4488** or sqlite3_result_error16() is negative then SQLite takes as the error
4489** message all text up through the first zero character.
4490** ^If the third parameter to sqlite3_result_error() or
4491** sqlite3_result_error16() is non-negative then SQLite takes that many
4492** bytes (not characters) from the 2nd parameter as the error message.
4493** ^The sqlite3_result_error() and sqlite3_result_error16()
4494** routines make a private copy of the error message text before
4495** they return.  Hence, the calling function can deallocate or
4496** modify the text after they return without harm.
4497** ^The sqlite3_result_error_code() function changes the error code
4498** returned by SQLite as a result of an error in a function.  ^By default,
4499** the error code is SQLITE_ERROR.  ^A subsequent call to sqlite3_result_error()
4500** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
4501**
4502** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an
4503** error indicating that a string or BLOB is too long to represent.
4504**
4505** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an
4506** error indicating that a memory allocation failed.
4507**
4508** ^The sqlite3_result_int() interface sets the return value
4509** of the application-defined function to be the 32-bit signed integer
4510** value given in the 2nd argument.
4511** ^The sqlite3_result_int64() interface sets the return value
4512** of the application-defined function to be the 64-bit signed integer
4513** value given in the 2nd argument.
4514**
4515** ^The sqlite3_result_null() interface sets the return value
4516** of the application-defined function to be NULL.
4517**
4518** ^The sqlite3_result_text(), sqlite3_result_text16(),
4519** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
4520** set the return value of the application-defined function to be
4521** a text string which is represented as UTF-8, UTF-16 native byte order,
4522** UTF-16 little endian, or UTF-16 big endian, respectively.
4523** ^The sqlite3_result_text64() interface sets the return value of an
4524** application-defined function to be a text string in an encoding
4525** specified by the fifth (and last) parameter, which must be one
4526** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE].
4527** ^SQLite takes the text result from the application from
4528** the 2nd parameter of the sqlite3_result_text* interfaces.
4529** ^If the 3rd parameter to the sqlite3_result_text* interfaces
4530** is negative, then SQLite takes result text from the 2nd parameter
4531** through the first zero character.
4532** ^If the 3rd parameter to the sqlite3_result_text* interfaces
4533** is non-negative, then as many bytes (not characters) of the text
4534** pointed to by the 2nd parameter are taken as the application-defined
4535** function result.  If the 3rd parameter is non-negative, then it
4536** must be the byte offset into the string where the NUL terminator would
4537** appear if the string where NUL terminated.  If any NUL characters occur
4538** in the string at a byte offset that is less than the value of the 3rd
4539** parameter, then the resulting string will contain embedded NULs and the
4540** result of expressions operating on strings with embedded NULs is undefined.
4541** ^If the 4th parameter to the sqlite3_result_text* interfaces
4542** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
4543** function as the destructor on the text or BLOB result when it has
4544** finished using that result.
4545** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
4546** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
4547** assumes that the text or BLOB result is in constant space and does not
4548** copy the content of the parameter nor call a destructor on the content
4549** when it has finished using that result.
4550** ^If the 4th parameter to the sqlite3_result_text* interfaces
4551** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
4552** then SQLite makes a copy of the result into space obtained from
4553** from [sqlite3_malloc()] before it returns.
4554**
4555** ^The sqlite3_result_value() interface sets the result of
4556** the application-defined function to be a copy the
4557** [unprotected sqlite3_value] object specified by the 2nd parameter.  ^The
4558** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
4559** so that the [sqlite3_value] specified in the parameter may change or
4560** be deallocated after sqlite3_result_value() returns without harm.
4561** ^A [protected sqlite3_value] object may always be used where an
4562** [unprotected sqlite3_value] object is required, so either
4563** kind of [sqlite3_value] object can be used with this interface.
4564**
4565** If these routines are called from within the different thread
4566** than the one containing the application-defined function that received
4567** the [sqlite3_context] pointer, the results are undefined.
4568*/
4569SQLITE_API void SQLITE_STDCALL sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
4570SQLITE_API void SQLITE_STDCALL sqlite3_result_blob64(sqlite3_context*,const void*,
4571                           sqlite3_uint64,void(*)(void*));
4572SQLITE_API void SQLITE_STDCALL sqlite3_result_double(sqlite3_context*, double);
4573SQLITE_API void SQLITE_STDCALL sqlite3_result_error(sqlite3_context*, const char*, int);
4574SQLITE_API void SQLITE_STDCALL sqlite3_result_error16(sqlite3_context*, const void*, int);
4575SQLITE_API void SQLITE_STDCALL sqlite3_result_error_toobig(sqlite3_context*);
4576SQLITE_API void SQLITE_STDCALL sqlite3_result_error_nomem(sqlite3_context*);
4577SQLITE_API void SQLITE_STDCALL sqlite3_result_error_code(sqlite3_context*, int);
4578SQLITE_API void SQLITE_STDCALL sqlite3_result_int(sqlite3_context*, int);
4579SQLITE_API void SQLITE_STDCALL sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
4580SQLITE_API void SQLITE_STDCALL sqlite3_result_null(sqlite3_context*);
4581SQLITE_API void SQLITE_STDCALL sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
4582SQLITE_API void SQLITE_STDCALL sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64,
4583                           void(*)(void*), unsigned char encoding);
4584SQLITE_API void SQLITE_STDCALL sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
4585SQLITE_API void SQLITE_STDCALL sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
4586SQLITE_API void SQLITE_STDCALL sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
4587SQLITE_API void SQLITE_STDCALL sqlite3_result_value(sqlite3_context*, sqlite3_value*);
4588SQLITE_API void SQLITE_STDCALL sqlite3_result_zeroblob(sqlite3_context*, int n);
4589
4590/*
4591** CAPI3REF: Define New Collating Sequences
4592**
4593** ^These functions add, remove, or modify a [collation] associated
4594** with the [database connection] specified as the first argument.
4595**
4596** ^The name of the collation is a UTF-8 string
4597** for sqlite3_create_collation() and sqlite3_create_collation_v2()
4598** and a UTF-16 string in native byte order for sqlite3_create_collation16().
4599** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
4600** considered to be the same name.
4601**
4602** ^(The third argument (eTextRep) must be one of the constants:
4603** <ul>
4604** <li> [SQLITE_UTF8],
4605** <li> [SQLITE_UTF16LE],
4606** <li> [SQLITE_UTF16BE],
4607** <li> [SQLITE_UTF16], or
4608** <li> [SQLITE_UTF16_ALIGNED].
4609** </ul>)^
4610** ^The eTextRep argument determines the encoding of strings passed
4611** to the collating function callback, xCallback.
4612** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
4613** force strings to be UTF16 with native byte order.
4614** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
4615** on an even byte address.
4616**
4617** ^The fourth argument, pArg, is an application data pointer that is passed
4618** through as the first argument to the collating function callback.
4619**
4620** ^The fifth argument, xCallback, is a pointer to the collating function.
4621** ^Multiple collating functions can be registered using the same name but
4622** with different eTextRep parameters and SQLite will use whichever
4623** function requires the least amount of data transformation.
4624** ^If the xCallback argument is NULL then the collating function is
4625** deleted.  ^When all collating functions having the same name are deleted,
4626** that collation is no longer usable.
4627**
4628** ^The collating function callback is invoked with a copy of the pArg
4629** application data pointer and with two strings in the encoding specified
4630** by the eTextRep argument.  The collating function must return an
4631** integer that is negative, zero, or positive
4632** if the first string is less than, equal to, or greater than the second,
4633** respectively.  A collating function must always return the same answer
4634** given the same inputs.  If two or more collating functions are registered
4635** to the same collation name (using different eTextRep values) then all
4636** must give an equivalent answer when invoked with equivalent strings.
4637** The collating function must obey the following properties for all
4638** strings A, B, and C:
4639**
4640** <ol>
4641** <li> If A==B then B==A.
4642** <li> If A==B and B==C then A==C.
4643** <li> If A&lt;B THEN B&gt;A.
4644** <li> If A&lt;B and B&lt;C then A&lt;C.
4645** </ol>
4646**
4647** If a collating function fails any of the above constraints and that
4648** collating function is  registered and used, then the behavior of SQLite
4649** is undefined.
4650**
4651** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
4652** with the addition that the xDestroy callback is invoked on pArg when
4653** the collating function is deleted.
4654** ^Collating functions are deleted when they are overridden by later
4655** calls to the collation creation functions or when the
4656** [database connection] is closed using [sqlite3_close()].
4657**
4658** ^The xDestroy callback is <u>not</u> called if the
4659** sqlite3_create_collation_v2() function fails.  Applications that invoke
4660** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
4661** check the return code and dispose of the application data pointer
4662** themselves rather than expecting SQLite to deal with it for them.
4663** This is different from every other SQLite interface.  The inconsistency
4664** is unfortunate but cannot be changed without breaking backwards
4665** compatibility.
4666**
4667** See also:  [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
4668*/
4669SQLITE_API int SQLITE_STDCALL sqlite3_create_collation(
4670  sqlite3*,
4671  const char *zName,
4672  int eTextRep,
4673  void *pArg,
4674  int(*xCompare)(void*,int,const void*,int,const void*)
4675);
4676SQLITE_API int SQLITE_STDCALL sqlite3_create_collation_v2(
4677  sqlite3*,
4678  const char *zName,
4679  int eTextRep,
4680  void *pArg,
4681  int(*xCompare)(void*,int,const void*,int,const void*),
4682  void(*xDestroy)(void*)
4683);
4684SQLITE_API int SQLITE_STDCALL sqlite3_create_collation16(
4685  sqlite3*,
4686  const void *zName,
4687  int eTextRep,
4688  void *pArg,
4689  int(*xCompare)(void*,int,const void*,int,const void*)
4690);
4691
4692/*
4693** CAPI3REF: Collation Needed Callbacks
4694**
4695** ^To avoid having to register all collation sequences before a database
4696** can be used, a single callback function may be registered with the
4697** [database connection] to be invoked whenever an undefined collation
4698** sequence is required.
4699**
4700** ^If the function is registered using the sqlite3_collation_needed() API,
4701** then it is passed the names of undefined collation sequences as strings
4702** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
4703** the names are passed as UTF-16 in machine native byte order.
4704** ^A call to either function replaces the existing collation-needed callback.
4705**
4706** ^(When the callback is invoked, the first argument passed is a copy
4707** of the second argument to sqlite3_collation_needed() or
4708** sqlite3_collation_needed16().  The second argument is the database
4709** connection.  The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
4710** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
4711** sequence function required.  The fourth parameter is the name of the
4712** required collation sequence.)^
4713**
4714** The callback function should register the desired collation using
4715** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
4716** [sqlite3_create_collation_v2()].
4717*/
4718SQLITE_API int SQLITE_STDCALL sqlite3_collation_needed(
4719  sqlite3*,
4720  void*,
4721  void(*)(void*,sqlite3*,int eTextRep,const char*)
4722);
4723SQLITE_API int SQLITE_STDCALL sqlite3_collation_needed16(
4724  sqlite3*,
4725  void*,
4726  void(*)(void*,sqlite3*,int eTextRep,const void*)
4727);
4728
4729#ifdef SQLITE_HAS_CODEC
4730/*
4731** Specify the key for an encrypted database.  This routine should be
4732** called right after sqlite3_open().
4733**
4734** The code to implement this API is not available in the public release
4735** of SQLite.
4736*/
4737SQLITE_API int SQLITE_STDCALL sqlite3_key(
4738  sqlite3 *db,                   /* Database to be rekeyed */
4739  const void *pKey, int nKey     /* The key */
4740);
4741SQLITE_API int SQLITE_STDCALL sqlite3_key_v2(
4742  sqlite3 *db,                   /* Database to be rekeyed */
4743  const char *zDbName,           /* Name of the database */
4744  const void *pKey, int nKey     /* The key */
4745);
4746
4747/*
4748** Change the key on an open database.  If the current database is not
4749** encrypted, this routine will encrypt it.  If pNew==0 or nNew==0, the
4750** database is decrypted.
4751**
4752** The code to implement this API is not available in the public release
4753** of SQLite.
4754*/
4755SQLITE_API int SQLITE_STDCALL sqlite3_rekey(
4756  sqlite3 *db,                   /* Database to be rekeyed */
4757  const void *pKey, int nKey     /* The new key */
4758);
4759SQLITE_API int SQLITE_STDCALL sqlite3_rekey_v2(
4760  sqlite3 *db,                   /* Database to be rekeyed */
4761  const char *zDbName,           /* Name of the database */
4762  const void *pKey, int nKey     /* The new key */
4763);
4764
4765/*
4766** Specify the activation key for a SEE database.  Unless
4767** activated, none of the SEE routines will work.
4768*/
4769SQLITE_API void SQLITE_STDCALL sqlite3_activate_see(
4770  const char *zPassPhrase        /* Activation phrase */
4771);
4772#endif
4773
4774#ifdef SQLITE_ENABLE_CEROD
4775/*
4776** Specify the activation key for a CEROD database.  Unless
4777** activated, none of the CEROD routines will work.
4778*/
4779SQLITE_API void SQLITE_STDCALL sqlite3_activate_cerod(
4780  const char *zPassPhrase        /* Activation phrase */
4781);
4782#endif
4783
4784/*
4785** CAPI3REF: Suspend Execution For A Short Time
4786**
4787** The sqlite3_sleep() function causes the current thread to suspend execution
4788** for at least a number of milliseconds specified in its parameter.
4789**
4790** If the operating system does not support sleep requests with
4791** millisecond time resolution, then the time will be rounded up to
4792** the nearest second. The number of milliseconds of sleep actually
4793** requested from the operating system is returned.
4794**
4795** ^SQLite implements this interface by calling the xSleep()
4796** method of the default [sqlite3_vfs] object.  If the xSleep() method
4797** of the default VFS is not implemented correctly, or not implemented at
4798** all, then the behavior of sqlite3_sleep() may deviate from the description
4799** in the previous paragraphs.
4800*/
4801SQLITE_API int SQLITE_STDCALL sqlite3_sleep(int);
4802
4803/*
4804** CAPI3REF: Name Of The Folder Holding Temporary Files
4805**
4806** ^(If this global variable is made to point to a string which is
4807** the name of a folder (a.k.a. directory), then all temporary files
4808** created by SQLite when using a built-in [sqlite3_vfs | VFS]
4809** will be placed in that directory.)^  ^If this variable
4810** is a NULL pointer, then SQLite performs a search for an appropriate
4811** temporary file directory.
4812**
4813** Applications are strongly discouraged from using this global variable.
4814** It is required to set a temporary folder on Windows Runtime (WinRT).
4815** But for all other platforms, it is highly recommended that applications
4816** neither read nor write this variable.  This global variable is a relic
4817** that exists for backwards compatibility of legacy applications and should
4818** be avoided in new projects.
4819**
4820** It is not safe to read or modify this variable in more than one
4821** thread at a time.  It is not safe to read or modify this variable
4822** if a [database connection] is being used at the same time in a separate
4823** thread.
4824** It is intended that this variable be set once
4825** as part of process initialization and before any SQLite interface
4826** routines have been called and that this variable remain unchanged
4827** thereafter.
4828**
4829** ^The [temp_store_directory pragma] may modify this variable and cause
4830** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
4831** the [temp_store_directory pragma] always assumes that any string
4832** that this variable points to is held in memory obtained from
4833** [sqlite3_malloc] and the pragma may attempt to free that memory
4834** using [sqlite3_free].
4835** Hence, if this variable is modified directly, either it should be
4836** made NULL or made to point to memory obtained from [sqlite3_malloc]
4837** or else the use of the [temp_store_directory pragma] should be avoided.
4838** Except when requested by the [temp_store_directory pragma], SQLite
4839** does not free the memory that sqlite3_temp_directory points to.  If
4840** the application wants that memory to be freed, it must do
4841** so itself, taking care to only do so after all [database connection]
4842** objects have been destroyed.
4843**
4844** <b>Note to Windows Runtime users:</b>  The temporary directory must be set
4845** prior to calling [sqlite3_open] or [sqlite3_open_v2].  Otherwise, various
4846** features that require the use of temporary files may fail.  Here is an
4847** example of how to do this using C++ with the Windows Runtime:
4848**
4849** <blockquote><pre>
4850** LPCWSTR zPath = Windows::Storage::ApplicationData::Current->
4851** &nbsp;     TemporaryFolder->Path->Data();
4852** char zPathBuf&#91;MAX_PATH + 1&#93;;
4853** memset(zPathBuf, 0, sizeof(zPathBuf));
4854** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),
4855** &nbsp;     NULL, NULL);
4856** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);
4857** </pre></blockquote>
4858*/
4859SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory;
4860
4861/*
4862** CAPI3REF: Name Of The Folder Holding Database Files
4863**
4864** ^(If this global variable is made to point to a string which is
4865** the name of a folder (a.k.a. directory), then all database files
4866** specified with a relative pathname and created or accessed by
4867** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed
4868** to be relative to that directory.)^ ^If this variable is a NULL
4869** pointer, then SQLite assumes that all database files specified
4870** with a relative pathname are relative to the current directory
4871** for the process.  Only the windows VFS makes use of this global
4872** variable; it is ignored by the unix VFS.
4873**
4874** Changing the value of this variable while a database connection is
4875** open can result in a corrupt database.
4876**
4877** It is not safe to read or modify this variable in more than one
4878** thread at a time.  It is not safe to read or modify this variable
4879** if a [database connection] is being used at the same time in a separate
4880** thread.
4881** It is intended that this variable be set once
4882** as part of process initialization and before any SQLite interface
4883** routines have been called and that this variable remain unchanged
4884** thereafter.
4885**
4886** ^The [data_store_directory pragma] may modify this variable and cause
4887** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
4888** the [data_store_directory pragma] always assumes that any string
4889** that this variable points to is held in memory obtained from
4890** [sqlite3_malloc] and the pragma may attempt to free that memory
4891** using [sqlite3_free].
4892** Hence, if this variable is modified directly, either it should be
4893** made NULL or made to point to memory obtained from [sqlite3_malloc]
4894** or else the use of the [data_store_directory pragma] should be avoided.
4895*/
4896SQLITE_API SQLITE_EXTERN char *sqlite3_data_directory;
4897
4898/*
4899** CAPI3REF: Test For Auto-Commit Mode
4900** KEYWORDS: {autocommit mode}
4901**
4902** ^The sqlite3_get_autocommit() interface returns non-zero or
4903** zero if the given database connection is or is not in autocommit mode,
4904** respectively.  ^Autocommit mode is on by default.
4905** ^Autocommit mode is disabled by a [BEGIN] statement.
4906** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
4907**
4908** If certain kinds of errors occur on a statement within a multi-statement
4909** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
4910** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
4911** transaction might be rolled back automatically.  The only way to
4912** find out whether SQLite automatically rolled back the transaction after
4913** an error is to use this function.
4914**
4915** If another thread changes the autocommit status of the database
4916** connection while this routine is running, then the return value
4917** is undefined.
4918*/
4919SQLITE_API int SQLITE_STDCALL sqlite3_get_autocommit(sqlite3*);
4920
4921/*
4922** CAPI3REF: Find The Database Handle Of A Prepared Statement
4923**
4924** ^The sqlite3_db_handle interface returns the [database connection] handle
4925** to which a [prepared statement] belongs.  ^The [database connection]
4926** returned by sqlite3_db_handle is the same [database connection]
4927** that was the first argument
4928** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
4929** create the statement in the first place.
4930*/
4931SQLITE_API sqlite3 *SQLITE_STDCALL sqlite3_db_handle(sqlite3_stmt*);
4932
4933/*
4934** CAPI3REF: Return The Filename For A Database Connection
4935**
4936** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename
4937** associated with database N of connection D.  ^The main database file
4938** has the name "main".  If there is no attached database N on the database
4939** connection D, or if database N is a temporary or in-memory database, then
4940** a NULL pointer is returned.
4941**
4942** ^The filename returned by this function is the output of the
4943** xFullPathname method of the [VFS].  ^In other words, the filename
4944** will be an absolute pathname, even if the filename used
4945** to open the database originally was a URI or relative pathname.
4946*/
4947SQLITE_API const char *SQLITE_STDCALL sqlite3_db_filename(sqlite3 *db, const char *zDbName);
4948
4949/*
4950** CAPI3REF: Determine if a database is read-only
4951**
4952** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N
4953** of connection D is read-only, 0 if it is read/write, or -1 if N is not
4954** the name of a database on connection D.
4955*/
4956SQLITE_API int SQLITE_STDCALL sqlite3_db_readonly(sqlite3 *db, const char *zDbName);
4957
4958/*
4959** CAPI3REF: Find the next prepared statement
4960**
4961** ^This interface returns a pointer to the next [prepared statement] after
4962** pStmt associated with the [database connection] pDb.  ^If pStmt is NULL
4963** then this interface returns a pointer to the first prepared statement
4964** associated with the database connection pDb.  ^If no prepared statement
4965** satisfies the conditions of this routine, it returns NULL.
4966**
4967** The [database connection] pointer D in a call to
4968** [sqlite3_next_stmt(D,S)] must refer to an open database
4969** connection and in particular must not be a NULL pointer.
4970*/
4971SQLITE_API sqlite3_stmt *SQLITE_STDCALL sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
4972
4973/*
4974** CAPI3REF: Commit And Rollback Notification Callbacks
4975**
4976** ^The sqlite3_commit_hook() interface registers a callback
4977** function to be invoked whenever a transaction is [COMMIT | committed].
4978** ^Any callback set by a previous call to sqlite3_commit_hook()
4979** for the same database connection is overridden.
4980** ^The sqlite3_rollback_hook() interface registers a callback
4981** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
4982** ^Any callback set by a previous call to sqlite3_rollback_hook()
4983** for the same database connection is overridden.
4984** ^The pArg argument is passed through to the callback.
4985** ^If the callback on a commit hook function returns non-zero,
4986** then the commit is converted into a rollback.
4987**
4988** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
4989** return the P argument from the previous call of the same function
4990** on the same [database connection] D, or NULL for
4991** the first call for each function on D.
4992**
4993** The commit and rollback hook callbacks are not reentrant.
4994** The callback implementation must not do anything that will modify
4995** the database connection that invoked the callback.  Any actions
4996** to modify the database connection must be deferred until after the
4997** completion of the [sqlite3_step()] call that triggered the commit
4998** or rollback hook in the first place.
4999** Note that running any other SQL statements, including SELECT statements,
5000** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
5001** the database connections for the meaning of "modify" in this paragraph.
5002**
5003** ^Registering a NULL function disables the callback.
5004**
5005** ^When the commit hook callback routine returns zero, the [COMMIT]
5006** operation is allowed to continue normally.  ^If the commit hook
5007** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
5008** ^The rollback hook is invoked on a rollback that results from a commit
5009** hook returning non-zero, just as it would be with any other rollback.
5010**
5011** ^For the purposes of this API, a transaction is said to have been
5012** rolled back if an explicit "ROLLBACK" statement is executed, or
5013** an error or constraint causes an implicit rollback to occur.
5014** ^The rollback callback is not invoked if a transaction is
5015** automatically rolled back because the database connection is closed.
5016**
5017** See also the [sqlite3_update_hook()] interface.
5018*/
5019SQLITE_API void *SQLITE_STDCALL sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
5020SQLITE_API void *SQLITE_STDCALL sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
5021
5022/*
5023** CAPI3REF: Data Change Notification Callbacks
5024**
5025** ^The sqlite3_update_hook() interface registers a callback function
5026** with the [database connection] identified by the first argument
5027** to be invoked whenever a row is updated, inserted or deleted in
5028** a rowid table.
5029** ^Any callback set by a previous call to this function
5030** for the same database connection is overridden.
5031**
5032** ^The second argument is a pointer to the function to invoke when a
5033** row is updated, inserted or deleted in a rowid table.
5034** ^The first argument to the callback is a copy of the third argument
5035** to sqlite3_update_hook().
5036** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
5037** or [SQLITE_UPDATE], depending on the operation that caused the callback
5038** to be invoked.
5039** ^The third and fourth arguments to the callback contain pointers to the
5040** database and table name containing the affected row.
5041** ^The final callback parameter is the [rowid] of the row.
5042** ^In the case of an update, this is the [rowid] after the update takes place.
5043**
5044** ^(The update hook is not invoked when internal system tables are
5045** modified (i.e. sqlite_master and sqlite_sequence).)^
5046** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified.
5047**
5048** ^In the current implementation, the update hook
5049** is not invoked when duplication rows are deleted because of an
5050** [ON CONFLICT | ON CONFLICT REPLACE] clause.  ^Nor is the update hook
5051** invoked when rows are deleted using the [truncate optimization].
5052** The exceptions defined in this paragraph might change in a future
5053** release of SQLite.
5054**
5055** The update hook implementation must not do anything that will modify
5056** the database connection that invoked the update hook.  Any actions
5057** to modify the database connection must be deferred until after the
5058** completion of the [sqlite3_step()] call that triggered the update hook.
5059** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
5060** database connections for the meaning of "modify" in this paragraph.
5061**
5062** ^The sqlite3_update_hook(D,C,P) function
5063** returns the P argument from the previous call
5064** on the same [database connection] D, or NULL for
5065** the first call on D.
5066**
5067** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()]
5068** interfaces.
5069*/
5070SQLITE_API void *SQLITE_STDCALL sqlite3_update_hook(
5071  sqlite3*,
5072  void(*)(void *,int ,char const *,char const *,sqlite3_int64),
5073  void*
5074);
5075
5076/*
5077** CAPI3REF: Enable Or Disable Shared Pager Cache
5078**
5079** ^(This routine enables or disables the sharing of the database cache
5080** and schema data structures between [database connection | connections]
5081** to the same database. Sharing is enabled if the argument is true
5082** and disabled if the argument is false.)^
5083**
5084** ^Cache sharing is enabled and disabled for an entire process.
5085** This is a change as of SQLite version 3.5.0. In prior versions of SQLite,
5086** sharing was enabled or disabled for each thread separately.
5087**
5088** ^(The cache sharing mode set by this interface effects all subsequent
5089** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
5090** Existing database connections continue use the sharing mode
5091** that was in effect at the time they were opened.)^
5092**
5093** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
5094** successfully.  An [error code] is returned otherwise.)^
5095**
5096** ^Shared cache is disabled by default. But this might change in
5097** future releases of SQLite.  Applications that care about shared
5098** cache setting should set it explicitly.
5099**
5100** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0
5101** and will always return SQLITE_MISUSE. On those systems,
5102** shared cache mode should be enabled per-database connection via
5103** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE].
5104**
5105** This interface is threadsafe on processors where writing a
5106** 32-bit integer is atomic.
5107**
5108** See Also:  [SQLite Shared-Cache Mode]
5109*/
5110SQLITE_API int SQLITE_STDCALL sqlite3_enable_shared_cache(int);
5111
5112/*
5113** CAPI3REF: Attempt To Free Heap Memory
5114**
5115** ^The sqlite3_release_memory() interface attempts to free N bytes
5116** of heap memory by deallocating non-essential memory allocations
5117** held by the database library.   Memory used to cache database
5118** pages to improve performance is an example of non-essential memory.
5119** ^sqlite3_release_memory() returns the number of bytes actually freed,
5120** which might be more or less than the amount requested.
5121** ^The sqlite3_release_memory() routine is a no-op returning zero
5122** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
5123**
5124** See also: [sqlite3_db_release_memory()]
5125*/
5126SQLITE_API int SQLITE_STDCALL sqlite3_release_memory(int);
5127
5128/*
5129** CAPI3REF: Free Memory Used By A Database Connection
5130**
5131** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap
5132** memory as possible from database connection D. Unlike the
5133** [sqlite3_release_memory()] interface, this interface is in effect even
5134** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
5135** omitted.
5136**
5137** See also: [sqlite3_release_memory()]
5138*/
5139SQLITE_API int SQLITE_STDCALL sqlite3_db_release_memory(sqlite3*);
5140
5141/*
5142** CAPI3REF: Impose A Limit On Heap Size
5143**
5144** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
5145** soft limit on the amount of heap memory that may be allocated by SQLite.
5146** ^SQLite strives to keep heap memory utilization below the soft heap
5147** limit by reducing the number of pages held in the page cache
5148** as heap memory usages approaches the limit.
5149** ^The soft heap limit is "soft" because even though SQLite strives to stay
5150** below the limit, it will exceed the limit rather than generate
5151** an [SQLITE_NOMEM] error.  In other words, the soft heap limit
5152** is advisory only.
5153**
5154** ^The return value from sqlite3_soft_heap_limit64() is the size of
5155** the soft heap limit prior to the call, or negative in the case of an
5156** error.  ^If the argument N is negative
5157** then no change is made to the soft heap limit.  Hence, the current
5158** size of the soft heap limit can be determined by invoking
5159** sqlite3_soft_heap_limit64() with a negative argument.
5160**
5161** ^If the argument N is zero then the soft heap limit is disabled.
5162**
5163** ^(The soft heap limit is not enforced in the current implementation
5164** if one or more of following conditions are true:
5165**
5166** <ul>
5167** <li> The soft heap limit is set to zero.
5168** <li> Memory accounting is disabled using a combination of the
5169**      [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
5170**      the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
5171** <li> An alternative page cache implementation is specified using
5172**      [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
5173** <li> The page cache allocates from its own memory pool supplied
5174**      by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
5175**      from the heap.
5176** </ul>)^
5177**
5178** Beginning with SQLite version 3.7.3, the soft heap limit is enforced
5179** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT]
5180** compile-time option is invoked.  With [SQLITE_ENABLE_MEMORY_MANAGEMENT],
5181** the soft heap limit is enforced on every memory allocation.  Without
5182** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced
5183** when memory is allocated by the page cache.  Testing suggests that because
5184** the page cache is the predominate memory user in SQLite, most
5185** applications will achieve adequate soft heap limit enforcement without
5186** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT].
5187**
5188** The circumstances under which SQLite will enforce the soft heap limit may
5189** changes in future releases of SQLite.
5190*/
5191SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_soft_heap_limit64(sqlite3_int64 N);
5192
5193/*
5194** CAPI3REF: Deprecated Soft Heap Limit Interface
5195** DEPRECATED
5196**
5197** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
5198** interface.  This routine is provided for historical compatibility
5199** only.  All new applications should use the
5200** [sqlite3_soft_heap_limit64()] interface rather than this one.
5201*/
5202SQLITE_API SQLITE_DEPRECATED void SQLITE_STDCALL sqlite3_soft_heap_limit(int N);
5203
5204
5205/*
5206** CAPI3REF: Extract Metadata About A Column Of A Table
5207**
5208** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns
5209** information about column C of table T in database D
5210** on [database connection] X.)^  ^The sqlite3_table_column_metadata()
5211** interface returns SQLITE_OK and fills in the non-NULL pointers in
5212** the final five arguments with appropriate values if the specified
5213** column exists.  ^The sqlite3_table_column_metadata() interface returns
5214** SQLITE_ERROR and if the specified column does not exist.
5215** ^If the column-name parameter to sqlite3_table_column_metadata() is a
5216** NULL pointer, then this routine simply checks for the existance of the
5217** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it
5218** does not.
5219**
5220** ^The column is identified by the second, third and fourth parameters to
5221** this function. ^(The second parameter is either the name of the database
5222** (i.e. "main", "temp", or an attached database) containing the specified
5223** table or NULL.)^ ^If it is NULL, then all attached databases are searched
5224** for the table using the same algorithm used by the database engine to
5225** resolve unqualified table references.
5226**
5227** ^The third and fourth parameters to this function are the table and column
5228** name of the desired column, respectively.
5229**
5230** ^Metadata is returned by writing to the memory locations passed as the 5th
5231** and subsequent parameters to this function. ^Any of these arguments may be
5232** NULL, in which case the corresponding element of metadata is omitted.
5233**
5234** ^(<blockquote>
5235** <table border="1">
5236** <tr><th> Parameter <th> Output<br>Type <th>  Description
5237**
5238** <tr><td> 5th <td> const char* <td> Data type
5239** <tr><td> 6th <td> const char* <td> Name of default collation sequence
5240** <tr><td> 7th <td> int         <td> True if column has a NOT NULL constraint
5241** <tr><td> 8th <td> int         <td> True if column is part of the PRIMARY KEY
5242** <tr><td> 9th <td> int         <td> True if column is [AUTOINCREMENT]
5243** </table>
5244** </blockquote>)^
5245**
5246** ^The memory pointed to by the character pointers returned for the
5247** declaration type and collation sequence is valid until the next
5248** call to any SQLite API function.
5249**
5250** ^If the specified table is actually a view, an [error code] is returned.
5251**
5252** ^If the specified column is "rowid", "oid" or "_rowid_" and the table
5253** is not a [WITHOUT ROWID] table and an
5254** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
5255** parameters are set for the explicitly declared column. ^(If there is no
5256** [INTEGER PRIMARY KEY] column, then the outputs
5257** for the [rowid] are set as follows:
5258**
5259** <pre>
5260**     data type: "INTEGER"
5261**     collation sequence: "BINARY"
5262**     not null: 0
5263**     primary key: 1
5264**     auto increment: 0
5265** </pre>)^
5266**
5267** ^This function causes all database schemas to be read from disk and
5268** parsed, if that has not already been done, and returns an error if
5269** any errors are encountered while loading the schema.
5270*/
5271SQLITE_API int SQLITE_STDCALL sqlite3_table_column_metadata(
5272  sqlite3 *db,                /* Connection handle */
5273  const char *zDbName,        /* Database name or NULL */
5274  const char *zTableName,     /* Table name */
5275  const char *zColumnName,    /* Column name */
5276  char const **pzDataType,    /* OUTPUT: Declared data type */
5277  char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
5278  int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
5279  int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
5280  int *pAutoinc               /* OUTPUT: True if column is auto-increment */
5281);
5282
5283/*
5284** CAPI3REF: Load An Extension
5285**
5286** ^This interface loads an SQLite extension library from the named file.
5287**
5288** ^The sqlite3_load_extension() interface attempts to load an
5289** [SQLite extension] library contained in the file zFile.  If
5290** the file cannot be loaded directly, attempts are made to load
5291** with various operating-system specific extensions added.
5292** So for example, if "samplelib" cannot be loaded, then names like
5293** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might
5294** be tried also.
5295**
5296** ^The entry point is zProc.
5297** ^(zProc may be 0, in which case SQLite will try to come up with an
5298** entry point name on its own.  It first tries "sqlite3_extension_init".
5299** If that does not work, it constructs a name "sqlite3_X_init" where the
5300** X is consists of the lower-case equivalent of all ASCII alphabetic
5301** characters in the filename from the last "/" to the first following
5302** "." and omitting any initial "lib".)^
5303** ^The sqlite3_load_extension() interface returns
5304** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
5305** ^If an error occurs and pzErrMsg is not 0, then the
5306** [sqlite3_load_extension()] interface shall attempt to
5307** fill *pzErrMsg with error message text stored in memory
5308** obtained from [sqlite3_malloc()]. The calling function
5309** should free this memory by calling [sqlite3_free()].
5310**
5311** ^Extension loading must be enabled using
5312** [sqlite3_enable_load_extension()] prior to calling this API,
5313** otherwise an error will be returned.
5314**
5315** See also the [load_extension() SQL function].
5316*/
5317SQLITE_API int SQLITE_STDCALL sqlite3_load_extension(
5318  sqlite3 *db,          /* Load the extension into this database connection */
5319  const char *zFile,    /* Name of the shared library containing extension */
5320  const char *zProc,    /* Entry point.  Derived from zFile if 0 */
5321  char **pzErrMsg       /* Put error message here if not 0 */
5322);
5323
5324/*
5325** CAPI3REF: Enable Or Disable Extension Loading
5326**
5327** ^So as not to open security holes in older applications that are
5328** unprepared to deal with [extension loading], and as a means of disabling
5329** [extension loading] while evaluating user-entered SQL, the following API
5330** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
5331**
5332** ^Extension loading is off by default.
5333** ^Call the sqlite3_enable_load_extension() routine with onoff==1
5334** to turn extension loading on and call it with onoff==0 to turn
5335** it back off again.
5336*/
5337SQLITE_API int SQLITE_STDCALL sqlite3_enable_load_extension(sqlite3 *db, int onoff);
5338
5339/*
5340** CAPI3REF: Automatically Load Statically Linked Extensions
5341**
5342** ^This interface causes the xEntryPoint() function to be invoked for
5343** each new [database connection] that is created.  The idea here is that
5344** xEntryPoint() is the entry point for a statically linked [SQLite extension]
5345** that is to be automatically loaded into all new database connections.
5346**
5347** ^(Even though the function prototype shows that xEntryPoint() takes
5348** no arguments and returns void, SQLite invokes xEntryPoint() with three
5349** arguments and expects and integer result as if the signature of the
5350** entry point where as follows:
5351**
5352** <blockquote><pre>
5353** &nbsp;  int xEntryPoint(
5354** &nbsp;    sqlite3 *db,
5355** &nbsp;    const char **pzErrMsg,
5356** &nbsp;    const struct sqlite3_api_routines *pThunk
5357** &nbsp;  );
5358** </pre></blockquote>)^
5359**
5360** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
5361** point to an appropriate error message (obtained from [sqlite3_mprintf()])
5362** and return an appropriate [error code].  ^SQLite ensures that *pzErrMsg
5363** is NULL before calling the xEntryPoint().  ^SQLite will invoke
5364** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns.  ^If any
5365** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
5366** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
5367**
5368** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
5369** on the list of automatic extensions is a harmless no-op. ^No entry point
5370** will be called more than once for each database connection that is opened.
5371**
5372** See also: [sqlite3_reset_auto_extension()]
5373** and [sqlite3_cancel_auto_extension()]
5374*/
5375SQLITE_API int SQLITE_STDCALL sqlite3_auto_extension(void (*xEntryPoint)(void));
5376
5377/*
5378** CAPI3REF: Cancel Automatic Extension Loading
5379**
5380** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the
5381** initialization routine X that was registered using a prior call to
5382** [sqlite3_auto_extension(X)].  ^The [sqlite3_cancel_auto_extension(X)]
5383** routine returns 1 if initialization routine X was successfully
5384** unregistered and it returns 0 if X was not on the list of initialization
5385** routines.
5386*/
5387SQLITE_API int SQLITE_STDCALL sqlite3_cancel_auto_extension(void (*xEntryPoint)(void));
5388
5389/*
5390** CAPI3REF: Reset Automatic Extension Loading
5391**
5392** ^This interface disables all automatic extensions previously
5393** registered using [sqlite3_auto_extension()].
5394*/
5395SQLITE_API void SQLITE_STDCALL sqlite3_reset_auto_extension(void);
5396
5397/*
5398** The interface to the virtual-table mechanism is currently considered
5399** to be experimental.  The interface might change in incompatible ways.
5400** If this is a problem for you, do not use the interface at this time.
5401**
5402** When the virtual-table mechanism stabilizes, we will declare the
5403** interface fixed, support it indefinitely, and remove this comment.
5404*/
5405
5406/*
5407** Structures used by the virtual table interface
5408*/
5409typedef struct sqlite3_vtab sqlite3_vtab;
5410typedef struct sqlite3_index_info sqlite3_index_info;
5411typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
5412typedef struct sqlite3_module sqlite3_module;
5413
5414/*
5415** CAPI3REF: Virtual Table Object
5416** KEYWORDS: sqlite3_module {virtual table module}
5417**
5418** This structure, sometimes called a "virtual table module",
5419** defines the implementation of a [virtual tables].
5420** This structure consists mostly of methods for the module.
5421**
5422** ^A virtual table module is created by filling in a persistent
5423** instance of this structure and passing a pointer to that instance
5424** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
5425** ^The registration remains valid until it is replaced by a different
5426** module or until the [database connection] closes.  The content
5427** of this structure must not change while it is registered with
5428** any database connection.
5429*/
5430struct sqlite3_module {
5431  int iVersion;
5432  int (*xCreate)(sqlite3*, void *pAux,
5433               int argc, const char *const*argv,
5434               sqlite3_vtab **ppVTab, char**);
5435  int (*xConnect)(sqlite3*, void *pAux,
5436               int argc, const char *const*argv,
5437               sqlite3_vtab **ppVTab, char**);
5438  int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
5439  int (*xDisconnect)(sqlite3_vtab *pVTab);
5440  int (*xDestroy)(sqlite3_vtab *pVTab);
5441  int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
5442  int (*xClose)(sqlite3_vtab_cursor*);
5443  int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
5444                int argc, sqlite3_value **argv);
5445  int (*xNext)(sqlite3_vtab_cursor*);
5446  int (*xEof)(sqlite3_vtab_cursor*);
5447  int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
5448  int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
5449  int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
5450  int (*xBegin)(sqlite3_vtab *pVTab);
5451  int (*xSync)(sqlite3_vtab *pVTab);
5452  int (*xCommit)(sqlite3_vtab *pVTab);
5453  int (*xRollback)(sqlite3_vtab *pVTab);
5454  int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
5455                       void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
5456                       void **ppArg);
5457  int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
5458  /* The methods above are in version 1 of the sqlite_module object. Those
5459  ** below are for version 2 and greater. */
5460  int (*xSavepoint)(sqlite3_vtab *pVTab, int);
5461  int (*xRelease)(sqlite3_vtab *pVTab, int);
5462  int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
5463};
5464
5465/*
5466** CAPI3REF: Virtual Table Indexing Information
5467** KEYWORDS: sqlite3_index_info
5468**
5469** The sqlite3_index_info structure and its substructures is used as part
5470** of the [virtual table] interface to
5471** pass information into and receive the reply from the [xBestIndex]
5472** method of a [virtual table module].  The fields under **Inputs** are the
5473** inputs to xBestIndex and are read-only.  xBestIndex inserts its
5474** results into the **Outputs** fields.
5475**
5476** ^(The aConstraint[] array records WHERE clause constraints of the form:
5477**
5478** <blockquote>column OP expr</blockquote>
5479**
5480** where OP is =, &lt;, &lt;=, &gt;, or &gt;=.)^  ^(The particular operator is
5481** stored in aConstraint[].op using one of the
5482** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
5483** ^(The index of the column is stored in
5484** aConstraint[].iColumn.)^  ^(aConstraint[].usable is TRUE if the
5485** expr on the right-hand side can be evaluated (and thus the constraint
5486** is usable) and false if it cannot.)^
5487**
5488** ^The optimizer automatically inverts terms of the form "expr OP column"
5489** and makes other simplifications to the WHERE clause in an attempt to
5490** get as many WHERE clause terms into the form shown above as possible.
5491** ^The aConstraint[] array only reports WHERE clause terms that are
5492** relevant to the particular virtual table being queried.
5493**
5494** ^Information about the ORDER BY clause is stored in aOrderBy[].
5495** ^Each term of aOrderBy records a column of the ORDER BY clause.
5496**
5497** The [xBestIndex] method must fill aConstraintUsage[] with information
5498** about what parameters to pass to xFilter.  ^If argvIndex>0 then
5499** the right-hand side of the corresponding aConstraint[] is evaluated
5500** and becomes the argvIndex-th entry in argv.  ^(If aConstraintUsage[].omit
5501** is true, then the constraint is assumed to be fully handled by the
5502** virtual table and is not checked again by SQLite.)^
5503**
5504** ^The idxNum and idxPtr values are recorded and passed into the
5505** [xFilter] method.
5506** ^[sqlite3_free()] is used to free idxPtr if and only if
5507** needToFreeIdxPtr is true.
5508**
5509** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
5510** the correct order to satisfy the ORDER BY clause so that no separate
5511** sorting step is required.
5512**
5513** ^The estimatedCost value is an estimate of the cost of a particular
5514** strategy. A cost of N indicates that the cost of the strategy is similar
5515** to a linear scan of an SQLite table with N rows. A cost of log(N)
5516** indicates that the expense of the operation is similar to that of a
5517** binary search on a unique indexed field of an SQLite table with N rows.
5518**
5519** ^The estimatedRows value is an estimate of the number of rows that
5520** will be returned by the strategy.
5521**
5522** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info
5523** structure for SQLite version 3.8.2. If a virtual table extension is
5524** used with an SQLite version earlier than 3.8.2, the results of attempting
5525** to read or write the estimatedRows field are undefined (but are likely
5526** to included crashing the application). The estimatedRows field should
5527** therefore only be used if [sqlite3_libversion_number()] returns a
5528** value greater than or equal to 3008002.
5529*/
5530struct sqlite3_index_info {
5531  /* Inputs */
5532  int nConstraint;           /* Number of entries in aConstraint */
5533  struct sqlite3_index_constraint {
5534     int iColumn;              /* Column on left-hand side of constraint */
5535     unsigned char op;         /* Constraint operator */
5536     unsigned char usable;     /* True if this constraint is usable */
5537     int iTermOffset;          /* Used internally - xBestIndex should ignore */
5538  } *aConstraint;            /* Table of WHERE clause constraints */
5539  int nOrderBy;              /* Number of terms in the ORDER BY clause */
5540  struct sqlite3_index_orderby {
5541     int iColumn;              /* Column number */
5542     unsigned char desc;       /* True for DESC.  False for ASC. */
5543  } *aOrderBy;               /* The ORDER BY clause */
5544  /* Outputs */
5545  struct sqlite3_index_constraint_usage {
5546    int argvIndex;           /* if >0, constraint is part of argv to xFilter */
5547    unsigned char omit;      /* Do not code a test for this constraint */
5548  } *aConstraintUsage;
5549  int idxNum;                /* Number used to identify the index */
5550  char *idxStr;              /* String, possibly obtained from sqlite3_malloc */
5551  int needToFreeIdxStr;      /* Free idxStr using sqlite3_free() if true */
5552  int orderByConsumed;       /* True if output is already ordered */
5553  double estimatedCost;           /* Estimated cost of using this index */
5554  /* Fields below are only available in SQLite 3.8.2 and later */
5555  sqlite3_int64 estimatedRows;    /* Estimated number of rows returned */
5556};
5557
5558/*
5559** CAPI3REF: Virtual Table Constraint Operator Codes
5560**
5561** These macros defined the allowed values for the
5562** [sqlite3_index_info].aConstraint[].op field.  Each value represents
5563** an operator that is part of a constraint term in the wHERE clause of
5564** a query that uses a [virtual table].
5565*/
5566#define SQLITE_INDEX_CONSTRAINT_EQ    2
5567#define SQLITE_INDEX_CONSTRAINT_GT    4
5568#define SQLITE_INDEX_CONSTRAINT_LE    8
5569#define SQLITE_INDEX_CONSTRAINT_LT    16
5570#define SQLITE_INDEX_CONSTRAINT_GE    32
5571#define SQLITE_INDEX_CONSTRAINT_MATCH 64
5572
5573/*
5574** CAPI3REF: Register A Virtual Table Implementation
5575**
5576** ^These routines are used to register a new [virtual table module] name.
5577** ^Module names must be registered before
5578** creating a new [virtual table] using the module and before using a
5579** preexisting [virtual table] for the module.
5580**
5581** ^The module name is registered on the [database connection] specified
5582** by the first parameter.  ^The name of the module is given by the
5583** second parameter.  ^The third parameter is a pointer to
5584** the implementation of the [virtual table module].   ^The fourth
5585** parameter is an arbitrary client data pointer that is passed through
5586** into the [xCreate] and [xConnect] methods of the virtual table module
5587** when a new virtual table is be being created or reinitialized.
5588**
5589** ^The sqlite3_create_module_v2() interface has a fifth parameter which
5590** is a pointer to a destructor for the pClientData.  ^SQLite will
5591** invoke the destructor function (if it is not NULL) when SQLite
5592** no longer needs the pClientData pointer.  ^The destructor will also
5593** be invoked if the call to sqlite3_create_module_v2() fails.
5594** ^The sqlite3_create_module()
5595** interface is equivalent to sqlite3_create_module_v2() with a NULL
5596** destructor.
5597*/
5598SQLITE_API int SQLITE_STDCALL sqlite3_create_module(
5599  sqlite3 *db,               /* SQLite connection to register module with */
5600  const char *zName,         /* Name of the module */
5601  const sqlite3_module *p,   /* Methods for the module */
5602  void *pClientData          /* Client data for xCreate/xConnect */
5603);
5604SQLITE_API int SQLITE_STDCALL sqlite3_create_module_v2(
5605  sqlite3 *db,               /* SQLite connection to register module with */
5606  const char *zName,         /* Name of the module */
5607  const sqlite3_module *p,   /* Methods for the module */
5608  void *pClientData,         /* Client data for xCreate/xConnect */
5609  void(*xDestroy)(void*)     /* Module destructor function */
5610);
5611
5612/*
5613** CAPI3REF: Virtual Table Instance Object
5614** KEYWORDS: sqlite3_vtab
5615**
5616** Every [virtual table module] implementation uses a subclass
5617** of this object to describe a particular instance
5618** of the [virtual table].  Each subclass will
5619** be tailored to the specific needs of the module implementation.
5620** The purpose of this superclass is to define certain fields that are
5621** common to all module implementations.
5622**
5623** ^Virtual tables methods can set an error message by assigning a
5624** string obtained from [sqlite3_mprintf()] to zErrMsg.  The method should
5625** take care that any prior string is freed by a call to [sqlite3_free()]
5626** prior to assigning a new string to zErrMsg.  ^After the error message
5627** is delivered up to the client application, the string will be automatically
5628** freed by sqlite3_free() and the zErrMsg field will be zeroed.
5629*/
5630struct sqlite3_vtab {
5631  const sqlite3_module *pModule;  /* The module for this virtual table */
5632  int nRef;                       /* Number of open cursors */
5633  char *zErrMsg;                  /* Error message from sqlite3_mprintf() */
5634  /* Virtual table implementations will typically add additional fields */
5635};
5636
5637/*
5638** CAPI3REF: Virtual Table Cursor Object
5639** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
5640**
5641** Every [virtual table module] implementation uses a subclass of the
5642** following structure to describe cursors that point into the
5643** [virtual table] and are used
5644** to loop through the virtual table.  Cursors are created using the
5645** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
5646** by the [sqlite3_module.xClose | xClose] method.  Cursors are used
5647** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
5648** of the module.  Each module implementation will define
5649** the content of a cursor structure to suit its own needs.
5650**
5651** This superclass exists in order to define fields of the cursor that
5652** are common to all implementations.
5653*/
5654struct sqlite3_vtab_cursor {
5655  sqlite3_vtab *pVtab;      /* Virtual table of this cursor */
5656  /* Virtual table implementations will typically add additional fields */
5657};
5658
5659/*
5660** CAPI3REF: Declare The Schema Of A Virtual Table
5661**
5662** ^The [xCreate] and [xConnect] methods of a
5663** [virtual table module] call this interface
5664** to declare the format (the names and datatypes of the columns) of
5665** the virtual tables they implement.
5666*/
5667SQLITE_API int SQLITE_STDCALL sqlite3_declare_vtab(sqlite3*, const char *zSQL);
5668
5669/*
5670** CAPI3REF: Overload A Function For A Virtual Table
5671**
5672** ^(Virtual tables can provide alternative implementations of functions
5673** using the [xFindFunction] method of the [virtual table module].
5674** But global versions of those functions
5675** must exist in order to be overloaded.)^
5676**
5677** ^(This API makes sure a global version of a function with a particular
5678** name and number of parameters exists.  If no such function exists
5679** before this API is called, a new function is created.)^  ^The implementation
5680** of the new function always causes an exception to be thrown.  So
5681** the new function is not good for anything by itself.  Its only
5682** purpose is to be a placeholder function that can be overloaded
5683** by a [virtual table].
5684*/
5685SQLITE_API int SQLITE_STDCALL sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
5686
5687/*
5688** The interface to the virtual-table mechanism defined above (back up
5689** to a comment remarkably similar to this one) is currently considered
5690** to be experimental.  The interface might change in incompatible ways.
5691** If this is a problem for you, do not use the interface at this time.
5692**
5693** When the virtual-table mechanism stabilizes, we will declare the
5694** interface fixed, support it indefinitely, and remove this comment.
5695*/
5696
5697/*
5698** CAPI3REF: A Handle To An Open BLOB
5699** KEYWORDS: {BLOB handle} {BLOB handles}
5700**
5701** An instance of this object represents an open BLOB on which
5702** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
5703** ^Objects of this type are created by [sqlite3_blob_open()]
5704** and destroyed by [sqlite3_blob_close()].
5705** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
5706** can be used to read or write small subsections of the BLOB.
5707** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
5708*/
5709typedef struct sqlite3_blob sqlite3_blob;
5710
5711/*
5712** CAPI3REF: Open A BLOB For Incremental I/O
5713**
5714** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
5715** in row iRow, column zColumn, table zTable in database zDb;
5716** in other words, the same BLOB that would be selected by:
5717**
5718** <pre>
5719**     SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
5720** </pre>)^
5721**
5722** ^(Parameter zDb is not the filename that contains the database, but
5723** rather the symbolic name of the database. For attached databases, this is
5724** the name that appears after the AS keyword in the [ATTACH] statement.
5725** For the main database file, the database name is "main". For TEMP
5726** tables, the database name is "temp".)^
5727**
5728** ^If the flags parameter is non-zero, then the BLOB is opened for read
5729** and write access. ^If the flags parameter is zero, the BLOB is opened for
5730** read-only access.
5731**
5732** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored
5733** in *ppBlob. Otherwise an [error code] is returned and, unless the error
5734** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided
5735** the API is not misused, it is always safe to call [sqlite3_blob_close()]
5736** on *ppBlob after this function it returns.
5737**
5738** This function fails with SQLITE_ERROR if any of the following are true:
5739** <ul>
5740**   <li> ^(Database zDb does not exist)^,
5741**   <li> ^(Table zTable does not exist within database zDb)^,
5742**   <li> ^(Table zTable is a WITHOUT ROWID table)^,
5743**   <li> ^(Column zColumn does not exist)^,
5744**   <li> ^(Row iRow is not present in the table)^,
5745**   <li> ^(The specified column of row iRow contains a value that is not
5746**         a TEXT or BLOB value)^,
5747**   <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE
5748**         constraint and the blob is being opened for read/write access)^,
5749**   <li> ^([foreign key constraints | Foreign key constraints] are enabled,
5750**         column zColumn is part of a [child key] definition and the blob is
5751**         being opened for read/write access)^.
5752** </ul>
5753**
5754** ^Unless it returns SQLITE_MISUSE, this function sets the
5755** [database connection] error code and message accessible via
5756** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
5757**
5758**
5759** ^(If the row that a BLOB handle points to is modified by an
5760** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
5761** then the BLOB handle is marked as "expired".
5762** This is true if any column of the row is changed, even a column
5763** other than the one the BLOB handle is open on.)^
5764** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
5765** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
5766** ^(Changes written into a BLOB prior to the BLOB expiring are not
5767** rolled back by the expiration of the BLOB.  Such changes will eventually
5768** commit if the transaction continues to completion.)^
5769**
5770** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
5771** the opened blob.  ^The size of a blob may not be changed by this
5772** interface.  Use the [UPDATE] SQL command to change the size of a
5773** blob.
5774**
5775** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
5776** and the built-in [zeroblob] SQL function may be used to create a
5777** zero-filled blob to read or write using the incremental-blob interface.
5778**
5779** To avoid a resource leak, every open [BLOB handle] should eventually
5780** be released by a call to [sqlite3_blob_close()].
5781*/
5782SQLITE_API int SQLITE_STDCALL sqlite3_blob_open(
5783  sqlite3*,
5784  const char *zDb,
5785  const char *zTable,
5786  const char *zColumn,
5787  sqlite3_int64 iRow,
5788  int flags,
5789  sqlite3_blob **ppBlob
5790);
5791
5792/*
5793** CAPI3REF: Move a BLOB Handle to a New Row
5794**
5795** ^This function is used to move an existing blob handle so that it points
5796** to a different row of the same database table. ^The new row is identified
5797** by the rowid value passed as the second argument. Only the row can be
5798** changed. ^The database, table and column on which the blob handle is open
5799** remain the same. Moving an existing blob handle to a new row can be
5800** faster than closing the existing handle and opening a new one.
5801**
5802** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
5803** it must exist and there must be either a blob or text value stored in
5804** the nominated column.)^ ^If the new row is not present in the table, or if
5805** it does not contain a blob or text value, or if another error occurs, an
5806** SQLite error code is returned and the blob handle is considered aborted.
5807** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
5808** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
5809** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
5810** always returns zero.
5811**
5812** ^This function sets the database handle error code and message.
5813*/
5814SQLITE_API SQLITE_EXPERIMENTAL int SQLITE_STDCALL sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
5815
5816/*
5817** CAPI3REF: Close A BLOB Handle
5818**
5819** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed
5820** unconditionally.  Even if this routine returns an error code, the
5821** handle is still closed.)^
5822**
5823** ^If the blob handle being closed was opened for read-write access, and if
5824** the database is in auto-commit mode and there are no other open read-write
5825** blob handles or active write statements, the current transaction is
5826** committed. ^If an error occurs while committing the transaction, an error
5827** code is returned and the transaction rolled back.
5828**
5829** Calling this function with an argument that is not a NULL pointer or an
5830** open blob handle results in undefined behaviour. ^Calling this routine
5831** with a null pointer (such as would be returned by a failed call to
5832** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function
5833** is passed a valid open blob handle, the values returned by the
5834** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning.
5835*/
5836SQLITE_API int SQLITE_STDCALL sqlite3_blob_close(sqlite3_blob *);
5837
5838/*
5839** CAPI3REF: Return The Size Of An Open BLOB
5840**
5841** ^Returns the size in bytes of the BLOB accessible via the
5842** successfully opened [BLOB handle] in its only argument.  ^The
5843** incremental blob I/O routines can only read or overwriting existing
5844** blob content; they cannot change the size of a blob.
5845**
5846** This routine only works on a [BLOB handle] which has been created
5847** by a prior successful call to [sqlite3_blob_open()] and which has not
5848** been closed by [sqlite3_blob_close()].  Passing any other pointer in
5849** to this routine results in undefined and probably undesirable behavior.
5850*/
5851SQLITE_API int SQLITE_STDCALL sqlite3_blob_bytes(sqlite3_blob *);
5852
5853/*
5854** CAPI3REF: Read Data From A BLOB Incrementally
5855**
5856** ^(This function is used to read data from an open [BLOB handle] into a
5857** caller-supplied buffer. N bytes of data are copied into buffer Z
5858** from the open BLOB, starting at offset iOffset.)^
5859**
5860** ^If offset iOffset is less than N bytes from the end of the BLOB,
5861** [SQLITE_ERROR] is returned and no data is read.  ^If N or iOffset is
5862** less than zero, [SQLITE_ERROR] is returned and no data is read.
5863** ^The size of the blob (and hence the maximum value of N+iOffset)
5864** can be determined using the [sqlite3_blob_bytes()] interface.
5865**
5866** ^An attempt to read from an expired [BLOB handle] fails with an
5867** error code of [SQLITE_ABORT].
5868**
5869** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
5870** Otherwise, an [error code] or an [extended error code] is returned.)^
5871**
5872** This routine only works on a [BLOB handle] which has been created
5873** by a prior successful call to [sqlite3_blob_open()] and which has not
5874** been closed by [sqlite3_blob_close()].  Passing any other pointer in
5875** to this routine results in undefined and probably undesirable behavior.
5876**
5877** See also: [sqlite3_blob_write()].
5878*/
5879SQLITE_API int SQLITE_STDCALL sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
5880
5881/*
5882** CAPI3REF: Write Data Into A BLOB Incrementally
5883**
5884** ^(This function is used to write data into an open [BLOB handle] from a
5885** caller-supplied buffer. N bytes of data are copied from the buffer Z
5886** into the open BLOB, starting at offset iOffset.)^
5887**
5888** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
5889** Otherwise, an  [error code] or an [extended error code] is returned.)^
5890** ^Unless SQLITE_MISUSE is returned, this function sets the
5891** [database connection] error code and message accessible via
5892** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
5893**
5894** ^If the [BLOB handle] passed as the first argument was not opened for
5895** writing (the flags parameter to [sqlite3_blob_open()] was zero),
5896** this function returns [SQLITE_READONLY].
5897**
5898** This function may only modify the contents of the BLOB; it is
5899** not possible to increase the size of a BLOB using this API.
5900** ^If offset iOffset is less than N bytes from the end of the BLOB,
5901** [SQLITE_ERROR] is returned and no data is written. The size of the
5902** BLOB (and hence the maximum value of N+iOffset) can be determined
5903** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less
5904** than zero [SQLITE_ERROR] is returned and no data is written.
5905**
5906** ^An attempt to write to an expired [BLOB handle] fails with an
5907** error code of [SQLITE_ABORT].  ^Writes to the BLOB that occurred
5908** before the [BLOB handle] expired are not rolled back by the
5909** expiration of the handle, though of course those changes might
5910** have been overwritten by the statement that expired the BLOB handle
5911** or by other independent statements.
5912**
5913** This routine only works on a [BLOB handle] which has been created
5914** by a prior successful call to [sqlite3_blob_open()] and which has not
5915** been closed by [sqlite3_blob_close()].  Passing any other pointer in
5916** to this routine results in undefined and probably undesirable behavior.
5917**
5918** See also: [sqlite3_blob_read()].
5919*/
5920SQLITE_API int SQLITE_STDCALL sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
5921
5922/*
5923** CAPI3REF: Virtual File System Objects
5924**
5925** A virtual filesystem (VFS) is an [sqlite3_vfs] object
5926** that SQLite uses to interact
5927** with the underlying operating system.  Most SQLite builds come with a
5928** single default VFS that is appropriate for the host computer.
5929** New VFSes can be registered and existing VFSes can be unregistered.
5930** The following interfaces are provided.
5931**
5932** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
5933** ^Names are case sensitive.
5934** ^Names are zero-terminated UTF-8 strings.
5935** ^If there is no match, a NULL pointer is returned.
5936** ^If zVfsName is NULL then the default VFS is returned.
5937**
5938** ^New VFSes are registered with sqlite3_vfs_register().
5939** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
5940** ^The same VFS can be registered multiple times without injury.
5941** ^To make an existing VFS into the default VFS, register it again
5942** with the makeDflt flag set.  If two different VFSes with the
5943** same name are registered, the behavior is undefined.  If a
5944** VFS is registered with a name that is NULL or an empty string,
5945** then the behavior is undefined.
5946**
5947** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
5948** ^(If the default VFS is unregistered, another VFS is chosen as
5949** the default.  The choice for the new VFS is arbitrary.)^
5950*/
5951SQLITE_API sqlite3_vfs *SQLITE_STDCALL sqlite3_vfs_find(const char *zVfsName);
5952SQLITE_API int SQLITE_STDCALL sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
5953SQLITE_API int SQLITE_STDCALL sqlite3_vfs_unregister(sqlite3_vfs*);
5954
5955/*
5956** CAPI3REF: Mutexes
5957**
5958** The SQLite core uses these routines for thread
5959** synchronization. Though they are intended for internal
5960** use by SQLite, code that links against SQLite is
5961** permitted to use any of these routines.
5962**
5963** The SQLite source code contains multiple implementations
5964** of these mutex routines.  An appropriate implementation
5965** is selected automatically at compile-time.  The following
5966** implementations are available in the SQLite core:
5967**
5968** <ul>
5969** <li>   SQLITE_MUTEX_PTHREADS
5970** <li>   SQLITE_MUTEX_W32
5971** <li>   SQLITE_MUTEX_NOOP
5972** </ul>
5973**
5974** The SQLITE_MUTEX_NOOP implementation is a set of routines
5975** that does no real locking and is appropriate for use in
5976** a single-threaded application.  The SQLITE_MUTEX_PTHREADS and
5977** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
5978** and Windows.
5979**
5980** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
5981** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
5982** implementation is included with the library. In this case the
5983** application must supply a custom mutex implementation using the
5984** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
5985** before calling sqlite3_initialize() or any other public sqlite3_
5986** function that calls sqlite3_initialize().
5987**
5988** ^The sqlite3_mutex_alloc() routine allocates a new
5989** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc()
5990** routine returns NULL if it is unable to allocate the requested
5991** mutex.  The argument to sqlite3_mutex_alloc() must one of these
5992** integer constants:
5993**
5994** <ul>
5995** <li>  SQLITE_MUTEX_FAST
5996** <li>  SQLITE_MUTEX_RECURSIVE
5997** <li>  SQLITE_MUTEX_STATIC_MASTER
5998** <li>  SQLITE_MUTEX_STATIC_MEM
5999** <li>  SQLITE_MUTEX_STATIC_OPEN
6000** <li>  SQLITE_MUTEX_STATIC_PRNG
6001** <li>  SQLITE_MUTEX_STATIC_LRU
6002** <li>  SQLITE_MUTEX_STATIC_PMEM
6003** <li>  SQLITE_MUTEX_STATIC_APP1
6004** <li>  SQLITE_MUTEX_STATIC_APP2
6005** <li>  SQLITE_MUTEX_STATIC_APP3
6006** </ul>
6007**
6008** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
6009** cause sqlite3_mutex_alloc() to create
6010** a new mutex.  ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
6011** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
6012** The mutex implementation does not need to make a distinction
6013** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
6014** not want to.  SQLite will only request a recursive mutex in
6015** cases where it really needs one.  If a faster non-recursive mutex
6016** implementation is available on the host platform, the mutex subsystem
6017** might return such a mutex in response to SQLITE_MUTEX_FAST.
6018**
6019** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
6020** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
6021** a pointer to a static preexisting mutex.  ^Nine static mutexes are
6022** used by the current version of SQLite.  Future versions of SQLite
6023** may add additional static mutexes.  Static mutexes are for internal
6024** use by SQLite only.  Applications that use SQLite mutexes should
6025** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
6026** SQLITE_MUTEX_RECURSIVE.
6027**
6028** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
6029** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
6030** returns a different mutex on every call.  ^For the static
6031** mutex types, the same mutex is returned on every call that has
6032** the same type number.
6033**
6034** ^The sqlite3_mutex_free() routine deallocates a previously
6035** allocated dynamic mutex.  Attempting to deallocate a static
6036** mutex results in undefined behavior.
6037**
6038** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
6039** to enter a mutex.  ^If another thread is already within the mutex,
6040** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
6041** SQLITE_BUSY.  ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
6042** upon successful entry.  ^(Mutexes created using
6043** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
6044** In such cases, the
6045** mutex must be exited an equal number of times before another thread
6046** can enter.)^  If the same thread tries to enter any mutex other
6047** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined.
6048**
6049** ^(Some systems (for example, Windows 95) do not support the operation
6050** implemented by sqlite3_mutex_try().  On those systems, sqlite3_mutex_try()
6051** will always return SQLITE_BUSY. The SQLite core only ever uses
6052** sqlite3_mutex_try() as an optimization so this is acceptable
6053** behavior.)^
6054**
6055** ^The sqlite3_mutex_leave() routine exits a mutex that was
6056** previously entered by the same thread.   The behavior
6057** is undefined if the mutex is not currently entered by the
6058** calling thread or is not currently allocated.
6059**
6060** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
6061** sqlite3_mutex_leave() is a NULL pointer, then all three routines
6062** behave as no-ops.
6063**
6064** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
6065*/
6066SQLITE_API sqlite3_mutex *SQLITE_STDCALL sqlite3_mutex_alloc(int);
6067SQLITE_API void SQLITE_STDCALL sqlite3_mutex_free(sqlite3_mutex*);
6068SQLITE_API void SQLITE_STDCALL sqlite3_mutex_enter(sqlite3_mutex*);
6069SQLITE_API int SQLITE_STDCALL sqlite3_mutex_try(sqlite3_mutex*);
6070SQLITE_API void SQLITE_STDCALL sqlite3_mutex_leave(sqlite3_mutex*);
6071
6072/*
6073** CAPI3REF: Mutex Methods Object
6074**
6075** An instance of this structure defines the low-level routines
6076** used to allocate and use mutexes.
6077**
6078** Usually, the default mutex implementations provided by SQLite are
6079** sufficient, however the application has the option of substituting a custom
6080** implementation for specialized deployments or systems for which SQLite
6081** does not provide a suitable implementation. In this case, the application
6082** creates and populates an instance of this structure to pass
6083** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
6084** Additionally, an instance of this structure can be used as an
6085** output variable when querying the system for the current mutex
6086** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
6087**
6088** ^The xMutexInit method defined by this structure is invoked as
6089** part of system initialization by the sqlite3_initialize() function.
6090** ^The xMutexInit routine is called by SQLite exactly once for each
6091** effective call to [sqlite3_initialize()].
6092**
6093** ^The xMutexEnd method defined by this structure is invoked as
6094** part of system shutdown by the sqlite3_shutdown() function. The
6095** implementation of this method is expected to release all outstanding
6096** resources obtained by the mutex methods implementation, especially
6097** those obtained by the xMutexInit method.  ^The xMutexEnd()
6098** interface is invoked exactly once for each call to [sqlite3_shutdown()].
6099**
6100** ^(The remaining seven methods defined by this structure (xMutexAlloc,
6101** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
6102** xMutexNotheld) implement the following interfaces (respectively):
6103**
6104** <ul>
6105**   <li>  [sqlite3_mutex_alloc()] </li>
6106**   <li>  [sqlite3_mutex_free()] </li>
6107**   <li>  [sqlite3_mutex_enter()] </li>
6108**   <li>  [sqlite3_mutex_try()] </li>
6109**   <li>  [sqlite3_mutex_leave()] </li>
6110**   <li>  [sqlite3_mutex_held()] </li>
6111**   <li>  [sqlite3_mutex_notheld()] </li>
6112** </ul>)^
6113**
6114** The only difference is that the public sqlite3_XXX functions enumerated
6115** above silently ignore any invocations that pass a NULL pointer instead
6116** of a valid mutex handle. The implementations of the methods defined
6117** by this structure are not required to handle this case, the results
6118** of passing a NULL pointer instead of a valid mutex handle are undefined
6119** (i.e. it is acceptable to provide an implementation that segfaults if
6120** it is passed a NULL pointer).
6121**
6122** The xMutexInit() method must be threadsafe.  It must be harmless to
6123** invoke xMutexInit() multiple times within the same process and without
6124** intervening calls to xMutexEnd().  Second and subsequent calls to
6125** xMutexInit() must be no-ops.
6126**
6127** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
6128** and its associates).  Similarly, xMutexAlloc() must not use SQLite memory
6129** allocation for a static mutex.  ^However xMutexAlloc() may use SQLite
6130** memory allocation for a fast or recursive mutex.
6131**
6132** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
6133** called, but only if the prior call to xMutexInit returned SQLITE_OK.
6134** If xMutexInit fails in any way, it is expected to clean up after itself
6135** prior to returning.
6136*/
6137typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
6138struct sqlite3_mutex_methods {
6139  int (*xMutexInit)(void);
6140  int (*xMutexEnd)(void);
6141  sqlite3_mutex *(*xMutexAlloc)(int);
6142  void (*xMutexFree)(sqlite3_mutex *);
6143  void (*xMutexEnter)(sqlite3_mutex *);
6144  int (*xMutexTry)(sqlite3_mutex *);
6145  void (*xMutexLeave)(sqlite3_mutex *);
6146  int (*xMutexHeld)(sqlite3_mutex *);
6147  int (*xMutexNotheld)(sqlite3_mutex *);
6148};
6149
6150/*
6151** CAPI3REF: Mutex Verification Routines
6152**
6153** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
6154** are intended for use inside assert() statements.  The SQLite core
6155** never uses these routines except inside an assert() and applications
6156** are advised to follow the lead of the core.  The SQLite core only
6157** provides implementations for these routines when it is compiled
6158** with the SQLITE_DEBUG flag.  External mutex implementations
6159** are only required to provide these routines if SQLITE_DEBUG is
6160** defined and if NDEBUG is not defined.
6161**
6162** These routines should return true if the mutex in their argument
6163** is held or not held, respectively, by the calling thread.
6164**
6165** The implementation is not required to provide versions of these
6166** routines that actually work. If the implementation does not provide working
6167** versions of these routines, it should at least provide stubs that always
6168** return true so that one does not get spurious assertion failures.
6169**
6170** If the argument to sqlite3_mutex_held() is a NULL pointer then
6171** the routine should return 1.   This seems counter-intuitive since
6172** clearly the mutex cannot be held if it does not exist.  But
6173** the reason the mutex does not exist is because the build is not
6174** using mutexes.  And we do not want the assert() containing the
6175** call to sqlite3_mutex_held() to fail, so a non-zero return is
6176** the appropriate thing to do.  The sqlite3_mutex_notheld()
6177** interface should also return 1 when given a NULL pointer.
6178*/
6179#ifndef NDEBUG
6180SQLITE_API int SQLITE_STDCALL sqlite3_mutex_held(sqlite3_mutex*);
6181SQLITE_API int SQLITE_STDCALL sqlite3_mutex_notheld(sqlite3_mutex*);
6182#endif
6183
6184/*
6185** CAPI3REF: Mutex Types
6186**
6187** The [sqlite3_mutex_alloc()] interface takes a single argument
6188** which is one of these integer constants.
6189**
6190** The set of static mutexes may change from one SQLite release to the
6191** next.  Applications that override the built-in mutex logic must be
6192** prepared to accommodate additional static mutexes.
6193*/
6194#define SQLITE_MUTEX_FAST             0
6195#define SQLITE_MUTEX_RECURSIVE        1
6196#define SQLITE_MUTEX_STATIC_MASTER    2
6197#define SQLITE_MUTEX_STATIC_MEM       3  /* sqlite3_malloc() */
6198#define SQLITE_MUTEX_STATIC_MEM2      4  /* NOT USED */
6199#define SQLITE_MUTEX_STATIC_OPEN      4  /* sqlite3BtreeOpen() */
6200#define SQLITE_MUTEX_STATIC_PRNG      5  /* sqlite3_random() */
6201#define SQLITE_MUTEX_STATIC_LRU       6  /* lru page list */
6202#define SQLITE_MUTEX_STATIC_LRU2      7  /* NOT USED */
6203#define SQLITE_MUTEX_STATIC_PMEM      7  /* sqlite3PageMalloc() */
6204#define SQLITE_MUTEX_STATIC_APP1      8  /* For use by application */
6205#define SQLITE_MUTEX_STATIC_APP2      9  /* For use by application */
6206#define SQLITE_MUTEX_STATIC_APP3     10  /* For use by application */
6207
6208/*
6209** CAPI3REF: Retrieve the mutex for a database connection
6210**
6211** ^This interface returns a pointer the [sqlite3_mutex] object that
6212** serializes access to the [database connection] given in the argument
6213** when the [threading mode] is Serialized.
6214** ^If the [threading mode] is Single-thread or Multi-thread then this
6215** routine returns a NULL pointer.
6216*/
6217SQLITE_API sqlite3_mutex *SQLITE_STDCALL sqlite3_db_mutex(sqlite3*);
6218
6219/*
6220** CAPI3REF: Low-Level Control Of Database Files
6221**
6222** ^The [sqlite3_file_control()] interface makes a direct call to the
6223** xFileControl method for the [sqlite3_io_methods] object associated
6224** with a particular database identified by the second argument. ^The
6225** name of the database is "main" for the main database or "temp" for the
6226** TEMP database, or the name that appears after the AS keyword for
6227** databases that are added using the [ATTACH] SQL command.
6228** ^A NULL pointer can be used in place of "main" to refer to the
6229** main database file.
6230** ^The third and fourth parameters to this routine
6231** are passed directly through to the second and third parameters of
6232** the xFileControl method.  ^The return value of the xFileControl
6233** method becomes the return value of this routine.
6234**
6235** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes
6236** a pointer to the underlying [sqlite3_file] object to be written into
6237** the space pointed to by the 4th parameter.  ^The SQLITE_FCNTL_FILE_POINTER
6238** case is a short-circuit path which does not actually invoke the
6239** underlying sqlite3_io_methods.xFileControl method.
6240**
6241** ^If the second parameter (zDbName) does not match the name of any
6242** open database file, then SQLITE_ERROR is returned.  ^This error
6243** code is not remembered and will not be recalled by [sqlite3_errcode()]
6244** or [sqlite3_errmsg()].  The underlying xFileControl method might
6245** also return SQLITE_ERROR.  There is no way to distinguish between
6246** an incorrect zDbName and an SQLITE_ERROR return from the underlying
6247** xFileControl method.
6248**
6249** See also: [SQLITE_FCNTL_LOCKSTATE]
6250*/
6251SQLITE_API int SQLITE_STDCALL sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
6252
6253/*
6254** CAPI3REF: Testing Interface
6255**
6256** ^The sqlite3_test_control() interface is used to read out internal
6257** state of SQLite and to inject faults into SQLite for testing
6258** purposes.  ^The first parameter is an operation code that determines
6259** the number, meaning, and operation of all subsequent parameters.
6260**
6261** This interface is not for use by applications.  It exists solely
6262** for verifying the correct operation of the SQLite library.  Depending
6263** on how the SQLite library is compiled, this interface might not exist.
6264**
6265** The details of the operation codes, their meanings, the parameters
6266** they take, and what they do are all subject to change without notice.
6267** Unlike most of the SQLite API, this function is not guaranteed to
6268** operate consistently from one release to the next.
6269*/
6270SQLITE_API int SQLITE_CDECL sqlite3_test_control(int op, ...);
6271
6272/*
6273** CAPI3REF: Testing Interface Operation Codes
6274**
6275** These constants are the valid operation code parameters used
6276** as the first argument to [sqlite3_test_control()].
6277**
6278** These parameters and their meanings are subject to change
6279** without notice.  These values are for testing purposes only.
6280** Applications should not use any of these parameters or the
6281** [sqlite3_test_control()] interface.
6282*/
6283#define SQLITE_TESTCTRL_FIRST                    5
6284#define SQLITE_TESTCTRL_PRNG_SAVE                5
6285#define SQLITE_TESTCTRL_PRNG_RESTORE             6
6286#define SQLITE_TESTCTRL_PRNG_RESET               7
6287#define SQLITE_TESTCTRL_BITVEC_TEST              8
6288#define SQLITE_TESTCTRL_FAULT_INSTALL            9
6289#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS     10
6290#define SQLITE_TESTCTRL_PENDING_BYTE            11
6291#define SQLITE_TESTCTRL_ASSERT                  12
6292#define SQLITE_TESTCTRL_ALWAYS                  13
6293#define SQLITE_TESTCTRL_RESERVE                 14
6294#define SQLITE_TESTCTRL_OPTIMIZATIONS           15
6295#define SQLITE_TESTCTRL_ISKEYWORD               16
6296#define SQLITE_TESTCTRL_SCRATCHMALLOC           17
6297#define SQLITE_TESTCTRL_LOCALTIME_FAULT         18
6298#define SQLITE_TESTCTRL_EXPLAIN_STMT            19  /* NOT USED */
6299#define SQLITE_TESTCTRL_NEVER_CORRUPT           20
6300#define SQLITE_TESTCTRL_VDBE_COVERAGE           21
6301#define SQLITE_TESTCTRL_BYTEORDER               22
6302#define SQLITE_TESTCTRL_ISINIT                  23
6303#define SQLITE_TESTCTRL_SORTER_MMAP             24
6304#define SQLITE_TESTCTRL_IMPOSTER                25
6305#define SQLITE_TESTCTRL_LAST                    25
6306
6307/*
6308** CAPI3REF: SQLite Runtime Status
6309**
6310** ^These interfaces are used to retrieve runtime status information
6311** about the performance of SQLite, and optionally to reset various
6312** highwater marks.  ^The first argument is an integer code for
6313** the specific parameter to measure.  ^(Recognized integer codes
6314** are of the form [status parameters | SQLITE_STATUS_...].)^
6315** ^The current value of the parameter is returned into *pCurrent.
6316** ^The highest recorded value is returned in *pHighwater.  ^If the
6317** resetFlag is true, then the highest record value is reset after
6318** *pHighwater is written.  ^(Some parameters do not record the highest
6319** value.  For those parameters
6320** nothing is written into *pHighwater and the resetFlag is ignored.)^
6321** ^(Other parameters record only the highwater mark and not the current
6322** value.  For these latter parameters nothing is written into *pCurrent.)^
6323**
6324** ^The sqlite3_status() and sqlite3_status64() routines return
6325** SQLITE_OK on success and a non-zero [error code] on failure.
6326**
6327** If either the current value or the highwater mark is too large to
6328** be represented by a 32-bit integer, then the values returned by
6329** sqlite3_status() are undefined.
6330**
6331** See also: [sqlite3_db_status()]
6332*/
6333SQLITE_API int SQLITE_STDCALL sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
6334SQLITE_API int SQLITE_STDCALL sqlite3_status64(
6335  int op,
6336  sqlite3_int64 *pCurrent,
6337  sqlite3_int64 *pHighwater,
6338  int resetFlag
6339);
6340
6341
6342/*
6343** CAPI3REF: Status Parameters
6344** KEYWORDS: {status parameters}
6345**
6346** These integer constants designate various run-time status parameters
6347** that can be returned by [sqlite3_status()].
6348**
6349** <dl>
6350** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
6351** <dd>This parameter is the current amount of memory checked out
6352** using [sqlite3_malloc()], either directly or indirectly.  The
6353** figure includes calls made to [sqlite3_malloc()] by the application
6354** and internal memory usage by the SQLite library.  Scratch memory
6355** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache
6356** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
6357** this parameter.  The amount returned is the sum of the allocation
6358** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
6359**
6360** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
6361** <dd>This parameter records the largest memory allocation request
6362** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
6363** internal equivalents).  Only the value returned in the
6364** *pHighwater parameter to [sqlite3_status()] is of interest.
6365** The value written into the *pCurrent parameter is undefined.</dd>)^
6366**
6367** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
6368** <dd>This parameter records the number of separate memory allocations
6369** currently checked out.</dd>)^
6370**
6371** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
6372** <dd>This parameter returns the number of pages used out of the
6373** [pagecache memory allocator] that was configured using
6374** [SQLITE_CONFIG_PAGECACHE].  The
6375** value returned is in pages, not in bytes.</dd>)^
6376**
6377** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]]
6378** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
6379** <dd>This parameter returns the number of bytes of page cache
6380** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
6381** buffer and where forced to overflow to [sqlite3_malloc()].  The
6382** returned value includes allocations that overflowed because they
6383** where too large (they were larger than the "sz" parameter to
6384** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
6385** no space was left in the page cache.</dd>)^
6386**
6387** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
6388** <dd>This parameter records the largest memory allocation request
6389** handed to [pagecache memory allocator].  Only the value returned in the
6390** *pHighwater parameter to [sqlite3_status()] is of interest.
6391** The value written into the *pCurrent parameter is undefined.</dd>)^
6392**
6393** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt>
6394** <dd>This parameter returns the number of allocations used out of the
6395** [scratch memory allocator] configured using
6396** [SQLITE_CONFIG_SCRATCH].  The value returned is in allocations, not
6397** in bytes.  Since a single thread may only have one scratch allocation
6398** outstanding at time, this parameter also reports the number of threads
6399** using scratch memory at the same time.</dd>)^
6400**
6401** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
6402** <dd>This parameter returns the number of bytes of scratch memory
6403** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH]
6404** buffer and where forced to overflow to [sqlite3_malloc()].  The values
6405** returned include overflows because the requested allocation was too
6406** larger (that is, because the requested allocation was larger than the
6407** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer
6408** slots were available.
6409** </dd>)^
6410**
6411** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
6412** <dd>This parameter records the largest memory allocation request
6413** handed to [scratch memory allocator].  Only the value returned in the
6414** *pHighwater parameter to [sqlite3_status()] is of interest.
6415** The value written into the *pCurrent parameter is undefined.</dd>)^
6416**
6417** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
6418** <dd>This parameter records the deepest parser stack.  It is only
6419** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
6420** </dl>
6421**
6422** New status parameters may be added from time to time.
6423*/
6424#define SQLITE_STATUS_MEMORY_USED          0
6425#define SQLITE_STATUS_PAGECACHE_USED       1
6426#define SQLITE_STATUS_PAGECACHE_OVERFLOW   2
6427#define SQLITE_STATUS_SCRATCH_USED         3
6428#define SQLITE_STATUS_SCRATCH_OVERFLOW     4
6429#define SQLITE_STATUS_MALLOC_SIZE          5
6430#define SQLITE_STATUS_PARSER_STACK         6
6431#define SQLITE_STATUS_PAGECACHE_SIZE       7
6432#define SQLITE_STATUS_SCRATCH_SIZE         8
6433#define SQLITE_STATUS_MALLOC_COUNT         9
6434
6435/*
6436** CAPI3REF: Database Connection Status
6437**
6438** ^This interface is used to retrieve runtime status information
6439** about a single [database connection].  ^The first argument is the
6440** database connection object to be interrogated.  ^The second argument
6441** is an integer constant, taken from the set of
6442** [SQLITE_DBSTATUS options], that
6443** determines the parameter to interrogate.  The set of
6444** [SQLITE_DBSTATUS options] is likely
6445** to grow in future releases of SQLite.
6446**
6447** ^The current value of the requested parameter is written into *pCur
6448** and the highest instantaneous value is written into *pHiwtr.  ^If
6449** the resetFlg is true, then the highest instantaneous value is
6450** reset back down to the current value.
6451**
6452** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
6453** non-zero [error code] on failure.
6454**
6455** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
6456*/
6457SQLITE_API int SQLITE_STDCALL sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
6458
6459/*
6460** CAPI3REF: Status Parameters for database connections
6461** KEYWORDS: {SQLITE_DBSTATUS options}
6462**
6463** These constants are the available integer "verbs" that can be passed as
6464** the second argument to the [sqlite3_db_status()] interface.
6465**
6466** New verbs may be added in future releases of SQLite. Existing verbs
6467** might be discontinued. Applications should check the return code from
6468** [sqlite3_db_status()] to make sure that the call worked.
6469** The [sqlite3_db_status()] interface will return a non-zero error code
6470** if a discontinued or unsupported verb is invoked.
6471**
6472** <dl>
6473** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
6474** <dd>This parameter returns the number of lookaside memory slots currently
6475** checked out.</dd>)^
6476**
6477** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
6478** <dd>This parameter returns the number malloc attempts that were
6479** satisfied using lookaside memory. Only the high-water value is meaningful;
6480** the current value is always zero.)^
6481**
6482** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]]
6483** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
6484** <dd>This parameter returns the number malloc attempts that might have
6485** been satisfied using lookaside memory but failed due to the amount of
6486** memory requested being larger than the lookaside slot size.
6487** Only the high-water value is meaningful;
6488** the current value is always zero.)^
6489**
6490** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]]
6491** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
6492** <dd>This parameter returns the number malloc attempts that might have
6493** been satisfied using lookaside memory but failed due to all lookaside
6494** memory already being in use.
6495** Only the high-water value is meaningful;
6496** the current value is always zero.)^
6497**
6498** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
6499** <dd>This parameter returns the approximate number of bytes of heap
6500** memory used by all pager caches associated with the database connection.)^
6501** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
6502**
6503** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
6504** <dd>This parameter returns the approximate number of bytes of heap
6505** memory used to store the schema for all databases associated
6506** with the connection - main, temp, and any [ATTACH]-ed databases.)^
6507** ^The full amount of memory used by the schemas is reported, even if the
6508** schema memory is shared with other database connections due to
6509** [shared cache mode] being enabled.
6510** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
6511**
6512** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
6513** <dd>This parameter returns the approximate number of bytes of heap
6514** and lookaside memory used by all prepared statements associated with
6515** the database connection.)^
6516** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
6517** </dd>
6518**
6519** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt>
6520** <dd>This parameter returns the number of pager cache hits that have
6521** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT
6522** is always 0.
6523** </dd>
6524**
6525** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt>
6526** <dd>This parameter returns the number of pager cache misses that have
6527** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS
6528** is always 0.
6529** </dd>
6530**
6531** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt>
6532** <dd>This parameter returns the number of dirty cache entries that have
6533** been written to disk. Specifically, the number of pages written to the
6534** wal file in wal mode databases, or the number of pages written to the
6535** database file in rollback mode databases. Any pages written as part of
6536** transaction rollback or database recovery operations are not included.
6537** If an IO or other error occurs while writing a page to disk, the effect
6538** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The
6539** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0.
6540** </dd>
6541**
6542** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt>
6543** <dd>This parameter returns zero for the current value if and only if
6544** all foreign key constraints (deferred or immediate) have been
6545** resolved.)^  ^The highwater mark is always 0.
6546** </dd>
6547** </dl>
6548*/
6549#define SQLITE_DBSTATUS_LOOKASIDE_USED       0
6550#define SQLITE_DBSTATUS_CACHE_USED           1
6551#define SQLITE_DBSTATUS_SCHEMA_USED          2
6552#define SQLITE_DBSTATUS_STMT_USED            3
6553#define SQLITE_DBSTATUS_LOOKASIDE_HIT        4
6554#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE  5
6555#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL  6
6556#define SQLITE_DBSTATUS_CACHE_HIT            7
6557#define SQLITE_DBSTATUS_CACHE_MISS           8
6558#define SQLITE_DBSTATUS_CACHE_WRITE          9
6559#define SQLITE_DBSTATUS_DEFERRED_FKS        10
6560#define SQLITE_DBSTATUS_MAX                 10   /* Largest defined DBSTATUS */
6561
6562
6563/*
6564** CAPI3REF: Prepared Statement Status
6565**
6566** ^(Each prepared statement maintains various
6567** [SQLITE_STMTSTATUS counters] that measure the number
6568** of times it has performed specific operations.)^  These counters can
6569** be used to monitor the performance characteristics of the prepared
6570** statements.  For example, if the number of table steps greatly exceeds
6571** the number of table searches or result rows, that would tend to indicate
6572** that the prepared statement is using a full table scan rather than
6573** an index.
6574**
6575** ^(This interface is used to retrieve and reset counter values from
6576** a [prepared statement].  The first argument is the prepared statement
6577** object to be interrogated.  The second argument
6578** is an integer code for a specific [SQLITE_STMTSTATUS counter]
6579** to be interrogated.)^
6580** ^The current value of the requested counter is returned.
6581** ^If the resetFlg is true, then the counter is reset to zero after this
6582** interface call returns.
6583**
6584** See also: [sqlite3_status()] and [sqlite3_db_status()].
6585*/
6586SQLITE_API int SQLITE_STDCALL sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
6587
6588/*
6589** CAPI3REF: Status Parameters for prepared statements
6590** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters}
6591**
6592** These preprocessor macros define integer codes that name counter
6593** values associated with the [sqlite3_stmt_status()] interface.
6594** The meanings of the various counters are as follows:
6595**
6596** <dl>
6597** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
6598** <dd>^This is the number of times that SQLite has stepped forward in
6599** a table as part of a full table scan.  Large numbers for this counter
6600** may indicate opportunities for performance improvement through
6601** careful use of indices.</dd>
6602**
6603** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt>
6604** <dd>^This is the number of sort operations that have occurred.
6605** A non-zero value in this counter may indicate an opportunity to
6606** improvement performance through careful use of indices.</dd>
6607**
6608** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
6609** <dd>^This is the number of rows inserted into transient indices that
6610** were created automatically in order to help joins run faster.
6611** A non-zero value in this counter may indicate an opportunity to
6612** improvement performance by adding permanent indices that do not
6613** need to be reinitialized each time the statement is run.</dd>
6614**
6615** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt>
6616** <dd>^This is the number of virtual machine operations executed
6617** by the prepared statement if that number is less than or equal
6618** to 2147483647.  The number of virtual machine operations can be
6619** used as a proxy for the total work done by the prepared statement.
6620** If the number of virtual machine operations exceeds 2147483647
6621** then the value returned by this statement status code is undefined.
6622** </dd>
6623** </dl>
6624*/
6625#define SQLITE_STMTSTATUS_FULLSCAN_STEP     1
6626#define SQLITE_STMTSTATUS_SORT              2
6627#define SQLITE_STMTSTATUS_AUTOINDEX         3
6628#define SQLITE_STMTSTATUS_VM_STEP           4
6629
6630/*
6631** CAPI3REF: Custom Page Cache Object
6632**
6633** The sqlite3_pcache type is opaque.  It is implemented by
6634** the pluggable module.  The SQLite core has no knowledge of
6635** its size or internal structure and never deals with the
6636** sqlite3_pcache object except by holding and passing pointers
6637** to the object.
6638**
6639** See [sqlite3_pcache_methods2] for additional information.
6640*/
6641typedef struct sqlite3_pcache sqlite3_pcache;
6642
6643/*
6644** CAPI3REF: Custom Page Cache Object
6645**
6646** The sqlite3_pcache_page object represents a single page in the
6647** page cache.  The page cache will allocate instances of this
6648** object.  Various methods of the page cache use pointers to instances
6649** of this object as parameters or as their return value.
6650**
6651** See [sqlite3_pcache_methods2] for additional information.
6652*/
6653typedef struct sqlite3_pcache_page sqlite3_pcache_page;
6654struct sqlite3_pcache_page {
6655  void *pBuf;        /* The content of the page */
6656  void *pExtra;      /* Extra information associated with the page */
6657};
6658
6659/*
6660** CAPI3REF: Application Defined Page Cache.
6661** KEYWORDS: {page cache}
6662**
6663** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can
6664** register an alternative page cache implementation by passing in an
6665** instance of the sqlite3_pcache_methods2 structure.)^
6666** In many applications, most of the heap memory allocated by
6667** SQLite is used for the page cache.
6668** By implementing a
6669** custom page cache using this API, an application can better control
6670** the amount of memory consumed by SQLite, the way in which
6671** that memory is allocated and released, and the policies used to
6672** determine exactly which parts of a database file are cached and for
6673** how long.
6674**
6675** The alternative page cache mechanism is an
6676** extreme measure that is only needed by the most demanding applications.
6677** The built-in page cache is recommended for most uses.
6678**
6679** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an
6680** internal buffer by SQLite within the call to [sqlite3_config].  Hence
6681** the application may discard the parameter after the call to
6682** [sqlite3_config()] returns.)^
6683**
6684** [[the xInit() page cache method]]
6685** ^(The xInit() method is called once for each effective
6686** call to [sqlite3_initialize()])^
6687** (usually only once during the lifetime of the process). ^(The xInit()
6688** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^
6689** The intent of the xInit() method is to set up global data structures
6690** required by the custom page cache implementation.
6691** ^(If the xInit() method is NULL, then the
6692** built-in default page cache is used instead of the application defined
6693** page cache.)^
6694**
6695** [[the xShutdown() page cache method]]
6696** ^The xShutdown() method is called by [sqlite3_shutdown()].
6697** It can be used to clean up
6698** any outstanding resources before process shutdown, if required.
6699** ^The xShutdown() method may be NULL.
6700**
6701** ^SQLite automatically serializes calls to the xInit method,
6702** so the xInit method need not be threadsafe.  ^The
6703** xShutdown method is only called from [sqlite3_shutdown()] so it does
6704** not need to be threadsafe either.  All other methods must be threadsafe
6705** in multithreaded applications.
6706**
6707** ^SQLite will never invoke xInit() more than once without an intervening
6708** call to xShutdown().
6709**
6710** [[the xCreate() page cache methods]]
6711** ^SQLite invokes the xCreate() method to construct a new cache instance.
6712** SQLite will typically create one cache instance for each open database file,
6713** though this is not guaranteed. ^The
6714** first parameter, szPage, is the size in bytes of the pages that must
6715** be allocated by the cache.  ^szPage will always a power of two.  ^The
6716** second parameter szExtra is a number of bytes of extra storage
6717** associated with each page cache entry.  ^The szExtra parameter will
6718** a number less than 250.  SQLite will use the
6719** extra szExtra bytes on each page to store metadata about the underlying
6720** database page on disk.  The value passed into szExtra depends
6721** on the SQLite version, the target platform, and how SQLite was compiled.
6722** ^The third argument to xCreate(), bPurgeable, is true if the cache being
6723** created will be used to cache database pages of a file stored on disk, or
6724** false if it is used for an in-memory database. The cache implementation
6725** does not have to do anything special based with the value of bPurgeable;
6726** it is purely advisory.  ^On a cache where bPurgeable is false, SQLite will
6727** never invoke xUnpin() except to deliberately delete a page.
6728** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
6729** false will always have the "discard" flag set to true.
6730** ^Hence, a cache created with bPurgeable false will
6731** never contain any unpinned pages.
6732**
6733** [[the xCachesize() page cache method]]
6734** ^(The xCachesize() method may be called at any time by SQLite to set the
6735** suggested maximum cache-size (number of pages stored by) the cache
6736** instance passed as the first argument. This is the value configured using
6737** the SQLite "[PRAGMA cache_size]" command.)^  As with the bPurgeable
6738** parameter, the implementation is not required to do anything with this
6739** value; it is advisory only.
6740**
6741** [[the xPagecount() page cache methods]]
6742** The xPagecount() method must return the number of pages currently
6743** stored in the cache, both pinned and unpinned.
6744**
6745** [[the xFetch() page cache methods]]
6746** The xFetch() method locates a page in the cache and returns a pointer to
6747** an sqlite3_pcache_page object associated with that page, or a NULL pointer.
6748** The pBuf element of the returned sqlite3_pcache_page object will be a
6749** pointer to a buffer of szPage bytes used to store the content of a
6750** single database page.  The pExtra element of sqlite3_pcache_page will be
6751** a pointer to the szExtra bytes of extra storage that SQLite has requested
6752** for each entry in the page cache.
6753**
6754** The page to be fetched is determined by the key. ^The minimum key value
6755** is 1.  After it has been retrieved using xFetch, the page is considered
6756** to be "pinned".
6757**
6758** If the requested page is already in the page cache, then the page cache
6759** implementation must return a pointer to the page buffer with its content
6760** intact.  If the requested page is not already in the cache, then the
6761** cache implementation should use the value of the createFlag
6762** parameter to help it determined what action to take:
6763**
6764** <table border=1 width=85% align=center>
6765** <tr><th> createFlag <th> Behavior when page is not already in cache
6766** <tr><td> 0 <td> Do not allocate a new page.  Return NULL.
6767** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
6768**                 Otherwise return NULL.
6769** <tr><td> 2 <td> Make every effort to allocate a new page.  Only return
6770**                 NULL if allocating a new page is effectively impossible.
6771** </table>
6772**
6773** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1.  SQLite
6774** will only use a createFlag of 2 after a prior call with a createFlag of 1
6775** failed.)^  In between the to xFetch() calls, SQLite may
6776** attempt to unpin one or more cache pages by spilling the content of
6777** pinned pages to disk and synching the operating system disk cache.
6778**
6779** [[the xUnpin() page cache method]]
6780** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
6781** as its second argument.  If the third parameter, discard, is non-zero,
6782** then the page must be evicted from the cache.
6783** ^If the discard parameter is
6784** zero, then the page may be discarded or retained at the discretion of
6785** page cache implementation. ^The page cache implementation
6786** may choose to evict unpinned pages at any time.
6787**
6788** The cache must not perform any reference counting. A single
6789** call to xUnpin() unpins the page regardless of the number of prior calls
6790** to xFetch().
6791**
6792** [[the xRekey() page cache methods]]
6793** The xRekey() method is used to change the key value associated with the
6794** page passed as the second argument. If the cache
6795** previously contains an entry associated with newKey, it must be
6796** discarded. ^Any prior cache entry associated with newKey is guaranteed not
6797** to be pinned.
6798**
6799** When SQLite calls the xTruncate() method, the cache must discard all
6800** existing cache entries with page numbers (keys) greater than or equal
6801** to the value of the iLimit parameter passed to xTruncate(). If any
6802** of these pages are pinned, they are implicitly unpinned, meaning that
6803** they can be safely discarded.
6804**
6805** [[the xDestroy() page cache method]]
6806** ^The xDestroy() method is used to delete a cache allocated by xCreate().
6807** All resources associated with the specified cache should be freed. ^After
6808** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
6809** handle invalid, and will not use it with any other sqlite3_pcache_methods2
6810** functions.
6811**
6812** [[the xShrink() page cache method]]
6813** ^SQLite invokes the xShrink() method when it wants the page cache to
6814** free up as much of heap memory as possible.  The page cache implementation
6815** is not obligated to free any memory, but well-behaved implementations should
6816** do their best.
6817*/
6818typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
6819struct sqlite3_pcache_methods2 {
6820  int iVersion;
6821  void *pArg;
6822  int (*xInit)(void*);
6823  void (*xShutdown)(void*);
6824  sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
6825  void (*xCachesize)(sqlite3_pcache*, int nCachesize);
6826  int (*xPagecount)(sqlite3_pcache*);
6827  sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
6828  void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
6829  void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*,
6830      unsigned oldKey, unsigned newKey);
6831  void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
6832  void (*xDestroy)(sqlite3_pcache*);
6833  void (*xShrink)(sqlite3_pcache*);
6834};
6835
6836/*
6837** This is the obsolete pcache_methods object that has now been replaced
6838** by sqlite3_pcache_methods2.  This object is not used by SQLite.  It is
6839** retained in the header file for backwards compatibility only.
6840*/
6841typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
6842struct sqlite3_pcache_methods {
6843  void *pArg;
6844  int (*xInit)(void*);
6845  void (*xShutdown)(void*);
6846  sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
6847  void (*xCachesize)(sqlite3_pcache*, int nCachesize);
6848  int (*xPagecount)(sqlite3_pcache*);
6849  void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
6850  void (*xUnpin)(sqlite3_pcache*, void*, int discard);
6851  void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
6852  void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
6853  void (*xDestroy)(sqlite3_pcache*);
6854};
6855
6856
6857/*
6858** CAPI3REF: Online Backup Object
6859**
6860** The sqlite3_backup object records state information about an ongoing
6861** online backup operation.  ^The sqlite3_backup object is created by
6862** a call to [sqlite3_backup_init()] and is destroyed by a call to
6863** [sqlite3_backup_finish()].
6864**
6865** See Also: [Using the SQLite Online Backup API]
6866*/
6867typedef struct sqlite3_backup sqlite3_backup;
6868
6869/*
6870** CAPI3REF: Online Backup API.
6871**
6872** The backup API copies the content of one database into another.
6873** It is useful either for creating backups of databases or
6874** for copying in-memory databases to or from persistent files.
6875**
6876** See Also: [Using the SQLite Online Backup API]
6877**
6878** ^SQLite holds a write transaction open on the destination database file
6879** for the duration of the backup operation.
6880** ^The source database is read-locked only while it is being read;
6881** it is not locked continuously for the entire backup operation.
6882** ^Thus, the backup may be performed on a live source database without
6883** preventing other database connections from
6884** reading or writing to the source database while the backup is underway.
6885**
6886** ^(To perform a backup operation:
6887**   <ol>
6888**     <li><b>sqlite3_backup_init()</b> is called once to initialize the
6889**         backup,
6890**     <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
6891**         the data between the two databases, and finally
6892**     <li><b>sqlite3_backup_finish()</b> is called to release all resources
6893**         associated with the backup operation.
6894**   </ol>)^
6895** There should be exactly one call to sqlite3_backup_finish() for each
6896** successful call to sqlite3_backup_init().
6897**
6898** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
6899**
6900** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
6901** [database connection] associated with the destination database
6902** and the database name, respectively.
6903** ^The database name is "main" for the main database, "temp" for the
6904** temporary database, or the name specified after the AS keyword in
6905** an [ATTACH] statement for an attached database.
6906** ^The S and M arguments passed to
6907** sqlite3_backup_init(D,N,S,M) identify the [database connection]
6908** and database name of the source database, respectively.
6909** ^The source and destination [database connections] (parameters S and D)
6910** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
6911** an error.
6912**
6913** ^A call to sqlite3_backup_init() will fail, returning SQLITE_ERROR, if
6914** there is already a read or read-write transaction open on the
6915** destination database.
6916**
6917** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
6918** returned and an error code and error message are stored in the
6919** destination [database connection] D.
6920** ^The error code and message for the failed call to sqlite3_backup_init()
6921** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
6922** [sqlite3_errmsg16()] functions.
6923** ^A successful call to sqlite3_backup_init() returns a pointer to an
6924** [sqlite3_backup] object.
6925** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
6926** sqlite3_backup_finish() functions to perform the specified backup
6927** operation.
6928**
6929** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
6930**
6931** ^Function sqlite3_backup_step(B,N) will copy up to N pages between
6932** the source and destination databases specified by [sqlite3_backup] object B.
6933** ^If N is negative, all remaining source pages are copied.
6934** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
6935** are still more pages to be copied, then the function returns [SQLITE_OK].
6936** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
6937** from source to destination, then it returns [SQLITE_DONE].
6938** ^If an error occurs while running sqlite3_backup_step(B,N),
6939** then an [error code] is returned. ^As well as [SQLITE_OK] and
6940** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
6941** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
6942** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
6943**
6944** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
6945** <ol>
6946** <li> the destination database was opened read-only, or
6947** <li> the destination database is using write-ahead-log journaling
6948** and the destination and source page sizes differ, or
6949** <li> the destination database is an in-memory database and the
6950** destination and source page sizes differ.
6951** </ol>)^
6952**
6953** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
6954** the [sqlite3_busy_handler | busy-handler function]
6955** is invoked (if one is specified). ^If the
6956** busy-handler returns non-zero before the lock is available, then
6957** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
6958** sqlite3_backup_step() can be retried later. ^If the source
6959** [database connection]
6960** is being used to write to the source database when sqlite3_backup_step()
6961** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
6962** case the call to sqlite3_backup_step() can be retried later on. ^(If
6963** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
6964** [SQLITE_READONLY] is returned, then
6965** there is no point in retrying the call to sqlite3_backup_step(). These
6966** errors are considered fatal.)^  The application must accept
6967** that the backup operation has failed and pass the backup operation handle
6968** to the sqlite3_backup_finish() to release associated resources.
6969**
6970** ^The first call to sqlite3_backup_step() obtains an exclusive lock
6971** on the destination file. ^The exclusive lock is not released until either
6972** sqlite3_backup_finish() is called or the backup operation is complete
6973** and sqlite3_backup_step() returns [SQLITE_DONE].  ^Every call to
6974** sqlite3_backup_step() obtains a [shared lock] on the source database that
6975** lasts for the duration of the sqlite3_backup_step() call.
6976** ^Because the source database is not locked between calls to
6977** sqlite3_backup_step(), the source database may be modified mid-way
6978** through the backup process.  ^If the source database is modified by an
6979** external process or via a database connection other than the one being
6980** used by the backup operation, then the backup will be automatically
6981** restarted by the next call to sqlite3_backup_step(). ^If the source
6982** database is modified by the using the same database connection as is used
6983** by the backup operation, then the backup database is automatically
6984** updated at the same time.
6985**
6986** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
6987**
6988** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the
6989** application wishes to abandon the backup operation, the application
6990** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
6991** ^The sqlite3_backup_finish() interfaces releases all
6992** resources associated with the [sqlite3_backup] object.
6993** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
6994** active write-transaction on the destination database is rolled back.
6995** The [sqlite3_backup] object is invalid
6996** and may not be used following a call to sqlite3_backup_finish().
6997**
6998** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
6999** sqlite3_backup_step() errors occurred, regardless or whether or not
7000** sqlite3_backup_step() completed.
7001** ^If an out-of-memory condition or IO error occurred during any prior
7002** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
7003** sqlite3_backup_finish() returns the corresponding [error code].
7004**
7005** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
7006** is not a permanent error and does not affect the return value of
7007** sqlite3_backup_finish().
7008**
7009** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]]
7010** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
7011**
7012** ^The sqlite3_backup_remaining() routine returns the number of pages still
7013** to be backed up at the conclusion of the most recent sqlite3_backup_step().
7014** ^The sqlite3_backup_pagecount() routine returns the total number of pages
7015** in the source database at the conclusion of the most recent
7016** sqlite3_backup_step().
7017** ^(The values returned by these functions are only updated by
7018** sqlite3_backup_step(). If the source database is modified in a way that
7019** changes the size of the source database or the number of pages remaining,
7020** those changes are not reflected in the output of sqlite3_backup_pagecount()
7021** and sqlite3_backup_remaining() until after the next
7022** sqlite3_backup_step().)^
7023**
7024** <b>Concurrent Usage of Database Handles</b>
7025**
7026** ^The source [database connection] may be used by the application for other
7027** purposes while a backup operation is underway or being initialized.
7028** ^If SQLite is compiled and configured to support threadsafe database
7029** connections, then the source database connection may be used concurrently
7030** from within other threads.
7031**
7032** However, the application must guarantee that the destination
7033** [database connection] is not passed to any other API (by any thread) after
7034** sqlite3_backup_init() is called and before the corresponding call to
7035** sqlite3_backup_finish().  SQLite does not currently check to see
7036** if the application incorrectly accesses the destination [database connection]
7037** and so no error code is reported, but the operations may malfunction
7038** nevertheless.  Use of the destination database connection while a
7039** backup is in progress might also also cause a mutex deadlock.
7040**
7041** If running in [shared cache mode], the application must
7042** guarantee that the shared cache used by the destination database
7043** is not accessed while the backup is running. In practice this means
7044** that the application must guarantee that the disk file being
7045** backed up to is not accessed by any connection within the process,
7046** not just the specific connection that was passed to sqlite3_backup_init().
7047**
7048** The [sqlite3_backup] object itself is partially threadsafe. Multiple
7049** threads may safely make multiple concurrent calls to sqlite3_backup_step().
7050** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
7051** APIs are not strictly speaking threadsafe. If they are invoked at the
7052** same time as another thread is invoking sqlite3_backup_step() it is
7053** possible that they return invalid values.
7054*/
7055SQLITE_API sqlite3_backup *SQLITE_STDCALL sqlite3_backup_init(
7056  sqlite3 *pDest,                        /* Destination database handle */
7057  const char *zDestName,                 /* Destination database name */
7058  sqlite3 *pSource,                      /* Source database handle */
7059  const char *zSourceName                /* Source database name */
7060);
7061SQLITE_API int SQLITE_STDCALL sqlite3_backup_step(sqlite3_backup *p, int nPage);
7062SQLITE_API int SQLITE_STDCALL sqlite3_backup_finish(sqlite3_backup *p);
7063SQLITE_API int SQLITE_STDCALL sqlite3_backup_remaining(sqlite3_backup *p);
7064SQLITE_API int SQLITE_STDCALL sqlite3_backup_pagecount(sqlite3_backup *p);
7065
7066/*
7067** CAPI3REF: Unlock Notification
7068**
7069** ^When running in shared-cache mode, a database operation may fail with
7070** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
7071** individual tables within the shared-cache cannot be obtained. See
7072** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
7073** ^This API may be used to register a callback that SQLite will invoke
7074** when the connection currently holding the required lock relinquishes it.
7075** ^This API is only available if the library was compiled with the
7076** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
7077**
7078** See Also: [Using the SQLite Unlock Notification Feature].
7079**
7080** ^Shared-cache locks are released when a database connection concludes
7081** its current transaction, either by committing it or rolling it back.
7082**
7083** ^When a connection (known as the blocked connection) fails to obtain a
7084** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
7085** identity of the database connection (the blocking connection) that
7086** has locked the required resource is stored internally. ^After an
7087** application receives an SQLITE_LOCKED error, it may call the
7088** sqlite3_unlock_notify() method with the blocked connection handle as
7089** the first argument to register for a callback that will be invoked
7090** when the blocking connections current transaction is concluded. ^The
7091** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
7092** call that concludes the blocking connections transaction.
7093**
7094** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
7095** there is a chance that the blocking connection will have already
7096** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
7097** If this happens, then the specified callback is invoked immediately,
7098** from within the call to sqlite3_unlock_notify().)^
7099**
7100** ^If the blocked connection is attempting to obtain a write-lock on a
7101** shared-cache table, and more than one other connection currently holds
7102** a read-lock on the same table, then SQLite arbitrarily selects one of
7103** the other connections to use as the blocking connection.
7104**
7105** ^(There may be at most one unlock-notify callback registered by a
7106** blocked connection. If sqlite3_unlock_notify() is called when the
7107** blocked connection already has a registered unlock-notify callback,
7108** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
7109** called with a NULL pointer as its second argument, then any existing
7110** unlock-notify callback is canceled. ^The blocked connections
7111** unlock-notify callback may also be canceled by closing the blocked
7112** connection using [sqlite3_close()].
7113**
7114** The unlock-notify callback is not reentrant. If an application invokes
7115** any sqlite3_xxx API functions from within an unlock-notify callback, a
7116** crash or deadlock may be the result.
7117**
7118** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
7119** returns SQLITE_OK.
7120**
7121** <b>Callback Invocation Details</b>
7122**
7123** When an unlock-notify callback is registered, the application provides a
7124** single void* pointer that is passed to the callback when it is invoked.
7125** However, the signature of the callback function allows SQLite to pass
7126** it an array of void* context pointers. The first argument passed to
7127** an unlock-notify callback is a pointer to an array of void* pointers,
7128** and the second is the number of entries in the array.
7129**
7130** When a blocking connections transaction is concluded, there may be
7131** more than one blocked connection that has registered for an unlock-notify
7132** callback. ^If two or more such blocked connections have specified the
7133** same callback function, then instead of invoking the callback function
7134** multiple times, it is invoked once with the set of void* context pointers
7135** specified by the blocked connections bundled together into an array.
7136** This gives the application an opportunity to prioritize any actions
7137** related to the set of unblocked database connections.
7138**
7139** <b>Deadlock Detection</b>
7140**
7141** Assuming that after registering for an unlock-notify callback a
7142** database waits for the callback to be issued before taking any further
7143** action (a reasonable assumption), then using this API may cause the
7144** application to deadlock. For example, if connection X is waiting for
7145** connection Y's transaction to be concluded, and similarly connection
7146** Y is waiting on connection X's transaction, then neither connection
7147** will proceed and the system may remain deadlocked indefinitely.
7148**
7149** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
7150** detection. ^If a given call to sqlite3_unlock_notify() would put the
7151** system in a deadlocked state, then SQLITE_LOCKED is returned and no
7152** unlock-notify callback is registered. The system is said to be in
7153** a deadlocked state if connection A has registered for an unlock-notify
7154** callback on the conclusion of connection B's transaction, and connection
7155** B has itself registered for an unlock-notify callback when connection
7156** A's transaction is concluded. ^Indirect deadlock is also detected, so
7157** the system is also considered to be deadlocked if connection B has
7158** registered for an unlock-notify callback on the conclusion of connection
7159** C's transaction, where connection C is waiting on connection A. ^Any
7160** number of levels of indirection are allowed.
7161**
7162** <b>The "DROP TABLE" Exception</b>
7163**
7164** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost
7165** always appropriate to call sqlite3_unlock_notify(). There is however,
7166** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
7167** SQLite checks if there are any currently executing SELECT statements
7168** that belong to the same connection. If there are, SQLITE_LOCKED is
7169** returned. In this case there is no "blocking connection", so invoking
7170** sqlite3_unlock_notify() results in the unlock-notify callback being
7171** invoked immediately. If the application then re-attempts the "DROP TABLE"
7172** or "DROP INDEX" query, an infinite loop might be the result.
7173**
7174** One way around this problem is to check the extended error code returned
7175** by an sqlite3_step() call. ^(If there is a blocking connection, then the
7176** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
7177** the special "DROP TABLE/INDEX" case, the extended error code is just
7178** SQLITE_LOCKED.)^
7179*/
7180SQLITE_API int SQLITE_STDCALL sqlite3_unlock_notify(
7181  sqlite3 *pBlocked,                          /* Waiting connection */
7182  void (*xNotify)(void **apArg, int nArg),    /* Callback function to invoke */
7183  void *pNotifyArg                            /* Argument to pass to xNotify */
7184);
7185
7186
7187/*
7188** CAPI3REF: String Comparison
7189**
7190** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications
7191** and extensions to compare the contents of two buffers containing UTF-8
7192** strings in a case-independent fashion, using the same definition of "case
7193** independence" that SQLite uses internally when comparing identifiers.
7194*/
7195SQLITE_API int SQLITE_STDCALL sqlite3_stricmp(const char *, const char *);
7196SQLITE_API int SQLITE_STDCALL sqlite3_strnicmp(const char *, const char *, int);
7197
7198/*
7199** CAPI3REF: String Globbing
7200*
7201** ^The [sqlite3_strglob(P,X)] interface returns zero if string X matches
7202** the glob pattern P, and it returns non-zero if string X does not match
7203** the glob pattern P.  ^The definition of glob pattern matching used in
7204** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the
7205** SQL dialect used by SQLite.  ^The sqlite3_strglob(P,X) function is case
7206** sensitive.
7207**
7208** Note that this routine returns zero on a match and non-zero if the strings
7209** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
7210*/
7211SQLITE_API int SQLITE_STDCALL sqlite3_strglob(const char *zGlob, const char *zStr);
7212
7213/*
7214** CAPI3REF: Error Logging Interface
7215**
7216** ^The [sqlite3_log()] interface writes a message into the [error log]
7217** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
7218** ^If logging is enabled, the zFormat string and subsequent arguments are
7219** used with [sqlite3_snprintf()] to generate the final output string.
7220**
7221** The sqlite3_log() interface is intended for use by extensions such as
7222** virtual tables, collating functions, and SQL functions.  While there is
7223** nothing to prevent an application from calling sqlite3_log(), doing so
7224** is considered bad form.
7225**
7226** The zFormat string must not be NULL.
7227**
7228** To avoid deadlocks and other threading problems, the sqlite3_log() routine
7229** will not use dynamically allocated memory.  The log message is stored in
7230** a fixed-length buffer on the stack.  If the log message is longer than
7231** a few hundred characters, it will be truncated to the length of the
7232** buffer.
7233*/
7234SQLITE_API void SQLITE_CDECL sqlite3_log(int iErrCode, const char *zFormat, ...);
7235
7236/*
7237** CAPI3REF: Write-Ahead Log Commit Hook
7238**
7239** ^The [sqlite3_wal_hook()] function is used to register a callback that
7240** is invoked each time data is committed to a database in wal mode.
7241**
7242** ^(The callback is invoked by SQLite after the commit has taken place and
7243** the associated write-lock on the database released)^, so the implementation
7244** may read, write or [checkpoint] the database as required.
7245**
7246** ^The first parameter passed to the callback function when it is invoked
7247** is a copy of the third parameter passed to sqlite3_wal_hook() when
7248** registering the callback. ^The second is a copy of the database handle.
7249** ^The third parameter is the name of the database that was written to -
7250** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
7251** is the number of pages currently in the write-ahead log file,
7252** including those that were just committed.
7253**
7254** The callback function should normally return [SQLITE_OK].  ^If an error
7255** code is returned, that error will propagate back up through the
7256** SQLite code base to cause the statement that provoked the callback
7257** to report an error, though the commit will have still occurred. If the
7258** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
7259** that does not correspond to any valid SQLite error code, the results
7260** are undefined.
7261**
7262** A single database handle may have at most a single write-ahead log callback
7263** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
7264** previously registered write-ahead log callback. ^Note that the
7265** [sqlite3_wal_autocheckpoint()] interface and the
7266** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
7267** those overwrite any prior [sqlite3_wal_hook()] settings.
7268*/
7269SQLITE_API void *SQLITE_STDCALL sqlite3_wal_hook(
7270  sqlite3*,
7271  int(*)(void *,sqlite3*,const char*,int),
7272  void*
7273);
7274
7275/*
7276** CAPI3REF: Configure an auto-checkpoint
7277**
7278** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
7279** [sqlite3_wal_hook()] that causes any database on [database connection] D
7280** to automatically [checkpoint]
7281** after committing a transaction if there are N or
7282** more frames in the [write-ahead log] file.  ^Passing zero or
7283** a negative value as the nFrame parameter disables automatic
7284** checkpoints entirely.
7285**
7286** ^The callback registered by this function replaces any existing callback
7287** registered using [sqlite3_wal_hook()].  ^Likewise, registering a callback
7288** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
7289** configured by this function.
7290**
7291** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
7292** from SQL.
7293**
7294** ^Checkpoints initiated by this mechanism are
7295** [sqlite3_wal_checkpoint_v2|PASSIVE].
7296**
7297** ^Every new [database connection] defaults to having the auto-checkpoint
7298** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
7299** pages.  The use of this interface
7300** is only necessary if the default setting is found to be suboptimal
7301** for a particular application.
7302*/
7303SQLITE_API int SQLITE_STDCALL sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
7304
7305/*
7306** CAPI3REF: Checkpoint a database
7307**
7308** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to
7309** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^
7310**
7311** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the
7312** [write-ahead log] for database X on [database connection] D to be
7313** transferred into the database file and for the write-ahead log to
7314** be reset.  See the [checkpointing] documentation for addition
7315** information.
7316**
7317** This interface used to be the only way to cause a checkpoint to
7318** occur.  But then the newer and more powerful [sqlite3_wal_checkpoint_v2()]
7319** interface was added.  This interface is retained for backwards
7320** compatibility and as a convenience for applications that need to manually
7321** start a callback but which do not need the full power (and corresponding
7322** complication) of [sqlite3_wal_checkpoint_v2()].
7323*/
7324SQLITE_API int SQLITE_STDCALL sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
7325
7326/*
7327** CAPI3REF: Checkpoint a database
7328**
7329** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint
7330** operation on database X of [database connection] D in mode M.  Status
7331** information is written back into integers pointed to by L and C.)^
7332** ^(The M parameter must be a valid [checkpoint mode]:)^
7333**
7334** <dl>
7335** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
7336**   ^Checkpoint as many frames as possible without waiting for any database
7337**   readers or writers to finish, then sync the database file if all frames
7338**   in the log were checkpointed. ^The [busy-handler callback]
7339**   is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode.
7340**   ^On the other hand, passive mode might leave the checkpoint unfinished
7341**   if there are concurrent readers or writers.
7342**
7343** <dt>SQLITE_CHECKPOINT_FULL<dd>
7344**   ^This mode blocks (it invokes the
7345**   [sqlite3_busy_handler|busy-handler callback]) until there is no
7346**   database writer and all readers are reading from the most recent database
7347**   snapshot. ^It then checkpoints all frames in the log file and syncs the
7348**   database file. ^This mode blocks new database writers while it is pending,
7349**   but new database readers are allowed to continue unimpeded.
7350**
7351** <dt>SQLITE_CHECKPOINT_RESTART<dd>
7352**   ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition
7353**   that after checkpointing the log file it blocks (calls the
7354**   [busy-handler callback])
7355**   until all readers are reading from the database file only. ^This ensures
7356**   that the next writer will restart the log file from the beginning.
7357**   ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new
7358**   database writer attempts while it is pending, but does not impede readers.
7359**
7360** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd>
7361**   ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the
7362**   addition that it also truncates the log file to zero bytes just prior
7363**   to a successful return.
7364** </dl>
7365**
7366** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in
7367** the log file or to -1 if the checkpoint could not run because
7368** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not
7369** NULL,then *pnCkpt is set to the total number of checkpointed frames in the
7370** log file (including any that were already checkpointed before the function
7371** was called) or to -1 if the checkpoint could not run due to an error or
7372** because the database is not in WAL mode. ^Note that upon successful
7373** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been
7374** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero.
7375**
7376** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If
7377** any other process is running a checkpoint operation at the same time, the
7378** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a
7379** busy-handler configured, it will not be invoked in this case.
7380**
7381** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the
7382** exclusive "writer" lock on the database file. ^If the writer lock cannot be
7383** obtained immediately, and a busy-handler is configured, it is invoked and
7384** the writer lock retried until either the busy-handler returns 0 or the lock
7385** is successfully obtained. ^The busy-handler is also invoked while waiting for
7386** database readers as described above. ^If the busy-handler returns 0 before
7387** the writer lock is obtained or while waiting for database readers, the
7388** checkpoint operation proceeds from that point in the same way as
7389** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible
7390** without blocking any further. ^SQLITE_BUSY is returned in this case.
7391**
7392** ^If parameter zDb is NULL or points to a zero length string, then the
7393** specified operation is attempted on all WAL databases [attached] to
7394** [database connection] db.  In this case the
7395** values written to output parameters *pnLog and *pnCkpt are undefined. ^If
7396** an SQLITE_BUSY error is encountered when processing one or more of the
7397** attached WAL databases, the operation is still attempted on any remaining
7398** attached databases and SQLITE_BUSY is returned at the end. ^If any other
7399** error occurs while processing an attached database, processing is abandoned
7400** and the error code is returned to the caller immediately. ^If no error
7401** (SQLITE_BUSY or otherwise) is encountered while processing the attached
7402** databases, SQLITE_OK is returned.
7403**
7404** ^If database zDb is the name of an attached database that is not in WAL
7405** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If
7406** zDb is not NULL (or a zero length string) and is not the name of any
7407** attached database, SQLITE_ERROR is returned to the caller.
7408**
7409** ^Unless it returns SQLITE_MISUSE,
7410** the sqlite3_wal_checkpoint_v2() interface
7411** sets the error information that is queried by
7412** [sqlite3_errcode()] and [sqlite3_errmsg()].
7413**
7414** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface
7415** from SQL.
7416*/
7417SQLITE_API int SQLITE_STDCALL sqlite3_wal_checkpoint_v2(
7418  sqlite3 *db,                    /* Database handle */
7419  const char *zDb,                /* Name of attached database (or NULL) */
7420  int eMode,                      /* SQLITE_CHECKPOINT_* value */
7421  int *pnLog,                     /* OUT: Size of WAL log in frames */
7422  int *pnCkpt                     /* OUT: Total number of frames checkpointed */
7423);
7424
7425/*
7426** CAPI3REF: Checkpoint Mode Values
7427** KEYWORDS: {checkpoint mode}
7428**
7429** These constants define all valid values for the "checkpoint mode" passed
7430** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface.
7431** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the
7432** meaning of each of these checkpoint modes.
7433*/
7434#define SQLITE_CHECKPOINT_PASSIVE  0  /* Do as much as possible w/o blocking */
7435#define SQLITE_CHECKPOINT_FULL     1  /* Wait for writers, then checkpoint */
7436#define SQLITE_CHECKPOINT_RESTART  2  /* Like FULL but wait for for readers */
7437#define SQLITE_CHECKPOINT_TRUNCATE 3  /* Like RESTART but also truncate WAL */
7438
7439/*
7440** CAPI3REF: Virtual Table Interface Configuration
7441**
7442** This function may be called by either the [xConnect] or [xCreate] method
7443** of a [virtual table] implementation to configure
7444** various facets of the virtual table interface.
7445**
7446** If this interface is invoked outside the context of an xConnect or
7447** xCreate virtual table method then the behavior is undefined.
7448**
7449** At present, there is only one option that may be configured using
7450** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].)  Further options
7451** may be added in the future.
7452*/
7453SQLITE_API int SQLITE_CDECL sqlite3_vtab_config(sqlite3*, int op, ...);
7454
7455/*
7456** CAPI3REF: Virtual Table Configuration Options
7457**
7458** These macros define the various options to the
7459** [sqlite3_vtab_config()] interface that [virtual table] implementations
7460** can use to customize and optimize their behavior.
7461**
7462** <dl>
7463** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT
7464** <dd>Calls of the form
7465** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
7466** where X is an integer.  If X is zero, then the [virtual table] whose
7467** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not
7468** support constraints.  In this configuration (which is the default) if
7469** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire
7470** statement is rolled back as if [ON CONFLICT | OR ABORT] had been
7471** specified as part of the users SQL statement, regardless of the actual
7472** ON CONFLICT mode specified.
7473**
7474** If X is non-zero, then the virtual table implementation guarantees
7475** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before
7476** any modifications to internal or persistent data structures have been made.
7477** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite
7478** is able to roll back a statement or database transaction, and abandon
7479** or continue processing the current SQL statement as appropriate.
7480** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns
7481** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode
7482** had been ABORT.
7483**
7484** Virtual table implementations that are required to handle OR REPLACE
7485** must do so within the [xUpdate] method. If a call to the
7486** [sqlite3_vtab_on_conflict()] function indicates that the current ON
7487** CONFLICT policy is REPLACE, the virtual table implementation should
7488** silently replace the appropriate rows within the xUpdate callback and
7489** return SQLITE_OK. Or, if this is not possible, it may return
7490** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT
7491** constraint handling.
7492** </dl>
7493*/
7494#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1
7495
7496/*
7497** CAPI3REF: Determine The Virtual Table Conflict Policy
7498**
7499** This function may only be called from within a call to the [xUpdate] method
7500** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The
7501** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
7502** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
7503** of the SQL statement that triggered the call to the [xUpdate] method of the
7504** [virtual table].
7505*/
7506SQLITE_API int SQLITE_STDCALL sqlite3_vtab_on_conflict(sqlite3 *);
7507
7508/*
7509** CAPI3REF: Conflict resolution modes
7510** KEYWORDS: {conflict resolution mode}
7511**
7512** These constants are returned by [sqlite3_vtab_on_conflict()] to
7513** inform a [virtual table] implementation what the [ON CONFLICT] mode
7514** is for the SQL statement being evaluated.
7515**
7516** Note that the [SQLITE_IGNORE] constant is also used as a potential
7517** return value from the [sqlite3_set_authorizer()] callback and that
7518** [SQLITE_ABORT] is also a [result code].
7519*/
7520#define SQLITE_ROLLBACK 1
7521/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
7522#define SQLITE_FAIL     3
7523/* #define SQLITE_ABORT 4  // Also an error code */
7524#define SQLITE_REPLACE  5
7525
7526/*
7527** CAPI3REF: Prepared Statement Scan Status Opcodes
7528** KEYWORDS: {scanstatus options}
7529**
7530** The following constants can be used for the T parameter to the
7531** [sqlite3_stmt_scanstatus(S,X,T,V)] interface.  Each constant designates a
7532** different metric for sqlite3_stmt_scanstatus() to return.
7533**
7534** When the value returned to V is a string, space to hold that string is
7535** managed by the prepared statement S and will be automatically freed when
7536** S is finalized.
7537**
7538** <dl>
7539** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt>
7540** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be
7541** set to the total number of times that the X-th loop has run.</dd>
7542**
7543** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt>
7544** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set
7545** to the total number of rows examined by all iterations of the X-th loop.</dd>
7546**
7547** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt>
7548** <dd>^The "double" variable pointed to by the T parameter will be set to the
7549** query planner's estimate for the average number of rows output from each
7550** iteration of the X-th loop.  If the query planner's estimates was accurate,
7551** then this value will approximate the quotient NVISIT/NLOOP and the
7552** product of this value for all prior loops with the same SELECTID will
7553** be the NLOOP value for the current loop.
7554**
7555** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt>
7556** <dd>^The "const char *" variable pointed to by the T parameter will be set
7557** to a zero-terminated UTF-8 string containing the name of the index or table
7558** used for the X-th loop.
7559**
7560** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt>
7561** <dd>^The "const char *" variable pointed to by the T parameter will be set
7562** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN]
7563** description for the X-th loop.
7564**
7565** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt>
7566** <dd>^The "int" variable pointed to by the T parameter will be set to the
7567** "select-id" for the X-th loop.  The select-id identifies which query or
7568** subquery the loop is part of.  The main query has a select-id of zero.
7569** The select-id is the same value as is output in the first column
7570** of an [EXPLAIN QUERY PLAN] query.
7571** </dl>
7572*/
7573#define SQLITE_SCANSTAT_NLOOP    0
7574#define SQLITE_SCANSTAT_NVISIT   1
7575#define SQLITE_SCANSTAT_EST      2
7576#define SQLITE_SCANSTAT_NAME     3
7577#define SQLITE_SCANSTAT_EXPLAIN  4
7578#define SQLITE_SCANSTAT_SELECTID 5
7579
7580/*
7581** CAPI3REF: Prepared Statement Scan Status
7582**
7583** This interface returns information about the predicted and measured
7584** performance for pStmt.  Advanced applications can use this
7585** interface to compare the predicted and the measured performance and
7586** issue warnings and/or rerun [ANALYZE] if discrepancies are found.
7587**
7588** Since this interface is expected to be rarely used, it is only
7589** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS]
7590** compile-time option.
7591**
7592** The "iScanStatusOp" parameter determines which status information to return.
7593** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior
7594** of this interface is undefined.
7595** ^The requested measurement is written into a variable pointed to by
7596** the "pOut" parameter.
7597** Parameter "idx" identifies the specific loop to retrieve statistics for.
7598** Loops are numbered starting from zero. ^If idx is out of range - less than
7599** zero or greater than or equal to the total number of loops used to implement
7600** the statement - a non-zero value is returned and the variable that pOut
7601** points to is unchanged.
7602**
7603** ^Statistics might not be available for all loops in all statements. ^In cases
7604** where there exist loops with no available statistics, this function behaves
7605** as if the loop did not exist - it returns non-zero and leave the variable
7606** that pOut points to unchanged.
7607**
7608** See also: [sqlite3_stmt_scanstatus_reset()]
7609*/
7610SQLITE_API SQLITE_EXPERIMENTAL int SQLITE_STDCALL sqlite3_stmt_scanstatus(
7611  sqlite3_stmt *pStmt,      /* Prepared statement for which info desired */
7612  int idx,                  /* Index of loop to report on */
7613  int iScanStatusOp,        /* Information desired.  SQLITE_SCANSTAT_* */
7614  void *pOut                /* Result written here */
7615);
7616
7617/*
7618** CAPI3REF: Zero Scan-Status Counters
7619**
7620** ^Zero all [sqlite3_stmt_scanstatus()] related event counters.
7621**
7622** This API is only available if the library is built with pre-processor
7623** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined.
7624*/
7625SQLITE_API SQLITE_EXPERIMENTAL void SQLITE_STDCALL sqlite3_stmt_scanstatus_reset(sqlite3_stmt*);
7626
7627
7628/*
7629** Undo the hack that converts floating point types to integer for
7630** builds on processors without floating point support.
7631*/
7632#ifdef SQLITE_OMIT_FLOATING_POINT
7633# undef double
7634#endif
7635
7636#ifdef __cplusplus
7637}  /* End of the 'extern "C"' block */
7638#endif
7639#endif /* _SQLITE3_H_ */
7640
7641/*
7642** 2010 August 30
7643**
7644** The author disclaims copyright to this source code.  In place of
7645** a legal notice, here is a blessing:
7646**
7647**    May you do good and not evil.
7648**    May you find forgiveness for yourself and forgive others.
7649**    May you share freely, never taking more than you give.
7650**
7651*************************************************************************
7652*/
7653
7654#ifndef _SQLITE3RTREE_H_
7655#define _SQLITE3RTREE_H_
7656
7657
7658#ifdef __cplusplus
7659extern "C" {
7660#endif
7661
7662typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry;
7663typedef struct sqlite3_rtree_query_info sqlite3_rtree_query_info;
7664
7665/* The double-precision datatype used by RTree depends on the
7666** SQLITE_RTREE_INT_ONLY compile-time option.
7667*/
7668#ifdef SQLITE_RTREE_INT_ONLY
7669  typedef sqlite3_int64 sqlite3_rtree_dbl;
7670#else
7671  typedef double sqlite3_rtree_dbl;
7672#endif
7673
7674/*
7675** Register a geometry callback named zGeom that can be used as part of an
7676** R-Tree geometry query as follows:
7677**
7678**   SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...)
7679*/
7680SQLITE_API int SQLITE_STDCALL sqlite3_rtree_geometry_callback(
7681  sqlite3 *db,
7682  const char *zGeom,
7683  int (*xGeom)(sqlite3_rtree_geometry*, int, sqlite3_rtree_dbl*,int*),
7684  void *pContext
7685);
7686
7687
7688/*
7689** A pointer to a structure of the following type is passed as the first
7690** argument to callbacks registered using rtree_geometry_callback().
7691*/
7692struct sqlite3_rtree_geometry {
7693  void *pContext;                 /* Copy of pContext passed to s_r_g_c() */
7694  int nParam;                     /* Size of array aParam[] */
7695  sqlite3_rtree_dbl *aParam;      /* Parameters passed to SQL geom function */
7696  void *pUser;                    /* Callback implementation user data */
7697  void (*xDelUser)(void *);       /* Called by SQLite to clean up pUser */
7698};
7699
7700/*
7701** Register a 2nd-generation geometry callback named zScore that can be
7702** used as part of an R-Tree geometry query as follows:
7703**
7704**   SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zQueryFunc(... params ...)
7705*/
7706SQLITE_API int SQLITE_STDCALL sqlite3_rtree_query_callback(
7707  sqlite3 *db,
7708  const char *zQueryFunc,
7709  int (*xQueryFunc)(sqlite3_rtree_query_info*),
7710  void *pContext,
7711  void (*xDestructor)(void*)
7712);
7713
7714
7715/*
7716** A pointer to a structure of the following type is passed as the
7717** argument to scored geometry callback registered using
7718** sqlite3_rtree_query_callback().
7719**
7720** Note that the first 5 fields of this structure are identical to
7721** sqlite3_rtree_geometry.  This structure is a subclass of
7722** sqlite3_rtree_geometry.
7723*/
7724struct sqlite3_rtree_query_info {
7725  void *pContext;                   /* pContext from when function registered */
7726  int nParam;                       /* Number of function parameters */
7727  sqlite3_rtree_dbl *aParam;        /* value of function parameters */
7728  void *pUser;                      /* callback can use this, if desired */
7729  void (*xDelUser)(void*);          /* function to free pUser */
7730  sqlite3_rtree_dbl *aCoord;        /* Coordinates of node or entry to check */
7731  unsigned int *anQueue;            /* Number of pending entries in the queue */
7732  int nCoord;                       /* Number of coordinates */
7733  int iLevel;                       /* Level of current node or entry */
7734  int mxLevel;                      /* The largest iLevel value in the tree */
7735  sqlite3_int64 iRowid;             /* Rowid for current entry */
7736  sqlite3_rtree_dbl rParentScore;   /* Score of parent node */
7737  int eParentWithin;                /* Visibility of parent node */
7738  int eWithin;                      /* OUT: Visiblity */
7739  sqlite3_rtree_dbl rScore;         /* OUT: Write the score here */
7740};
7741
7742/*
7743** Allowed values for sqlite3_rtree_query.eWithin and .eParentWithin.
7744*/
7745#define NOT_WITHIN       0   /* Object completely outside of query region */
7746#define PARTLY_WITHIN    1   /* Object partially overlaps query region */
7747#define FULLY_WITHIN     2   /* Object fully contained within query region */
7748
7749
7750#ifdef __cplusplus
7751}  /* end of the 'extern "C"' block */
7752#endif
7753
7754#endif  /* ifndef _SQLITE3RTREE_H_ */
7755
7756