1/* 2** 2001 September 15 3** 4** The author disclaims copyright to this source code. In place of 5** a legal notice, here is a blessing: 6** 7** May you do good and not evil. 8** May you find forgiveness for yourself and forgive others. 9** May you share freely, never taking more than you give. 10** 11************************************************************************* 12** This header file defines the interface that the SQLite library 13** presents to client programs. If a C-function, structure, datatype, 14** or constant definition does not appear in this file, then it is 15** not a published API of SQLite, is subject to change without 16** notice, and should not be referenced by programs that use SQLite. 17** 18** Some of the definitions that are in this file are marked as 19** "experimental". Experimental interfaces are normally new 20** features recently added to SQLite. We do not anticipate changes 21** to experimental interfaces but reserve the right to make minor changes 22** if experience from use "in the wild" suggest such changes are prudent. 23** 24** The official C-language API documentation for SQLite is derived 25** from comments in this file. This file is the authoritative source 26** on how SQLite interfaces are suppose to operate. 27** 28** The name of this file under configuration management is "sqlite.h.in". 29** The makefile makes some minor changes to this file (such as inserting 30** the version number) and changes its name to "sqlite3.h" as 31** part of the build process. 32*/ 33#ifndef _SQLITE3_H_ 34#define _SQLITE3_H_ 35#include <stdarg.h> /* Needed for the definition of va_list */ 36 37/* 38** Make sure we can call this stuff from C++. 39*/ 40#ifdef __cplusplus 41extern "C" { 42#endif 43 44 45/* 46** Add the ability to override 'extern' 47*/ 48#ifndef SQLITE_EXTERN 49# define SQLITE_EXTERN extern 50#endif 51 52#ifndef SQLITE_API 53# define SQLITE_API 54#endif 55 56 57/* 58** These no-op macros are used in front of interfaces to mark those 59** interfaces as either deprecated or experimental. New applications 60** should not use deprecated interfaces - they are support for backwards 61** compatibility only. Application writers should be aware that 62** experimental interfaces are subject to change in point releases. 63** 64** These macros used to resolve to various kinds of compiler magic that 65** would generate warning messages when they were used. But that 66** compiler magic ended up generating such a flurry of bug reports 67** that we have taken it all out and gone back to using simple 68** noop macros. 69*/ 70#define SQLITE_DEPRECATED 71#define SQLITE_EXPERIMENTAL 72 73/* 74** Ensure these symbols were not defined by some previous header file. 75*/ 76#ifdef SQLITE_VERSION 77# undef SQLITE_VERSION 78#endif 79#ifdef SQLITE_VERSION_NUMBER 80# undef SQLITE_VERSION_NUMBER 81#endif 82 83/* 84** CAPI3REF: Compile-Time Library Version Numbers 85** 86** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header 87** evaluates to a string literal that is the SQLite version in the 88** format "X.Y.Z" where X is the major version number (always 3 for 89** SQLite3) and Y is the minor version number and Z is the release number.)^ 90** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer 91** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same 92** numbers used in [SQLITE_VERSION].)^ 93** The SQLITE_VERSION_NUMBER for any given release of SQLite will also 94** be larger than the release from which it is derived. Either Y will 95** be held constant and Z will be incremented or else Y will be incremented 96** and Z will be reset to zero. 97** 98** Since version 3.6.18, SQLite source code has been stored in the 99** <a href="http://www.fossil-scm.org/">Fossil configuration management 100** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to 101** a string which identifies a particular check-in of SQLite 102** within its configuration management system. ^The SQLITE_SOURCE_ID 103** string contains the date and time of the check-in (UTC) and an SHA1 104** hash of the entire source tree. 105** 106** See also: [sqlite3_libversion()], 107** [sqlite3_libversion_number()], [sqlite3_sourceid()], 108** [sqlite_version()] and [sqlite_source_id()]. 109*/ 110#define SQLITE_VERSION "3.7.2" 111#define SQLITE_VERSION_NUMBER 3007002 112#define SQLITE_SOURCE_ID "2010-08-23 18:52:01 42537b60566f288167f1b5864a5435986838e3a3" 113 114/* 115** CAPI3REF: Run-Time Library Version Numbers 116** KEYWORDS: sqlite3_version, sqlite3_sourceid 117** 118** These interfaces provide the same information as the [SQLITE_VERSION], 119** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros 120** but are associated with the library instead of the header file. ^(Cautious 121** programmers might include assert() statements in their application to 122** verify that values returned by these interfaces match the macros in 123** the header, and thus insure that the application is 124** compiled with matching library and header files. 125** 126** <blockquote><pre> 127** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER ); 128** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 ); 129** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 ); 130** </pre></blockquote>)^ 131** 132** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION] 133** macro. ^The sqlite3_libversion() function returns a pointer to the 134** to the sqlite3_version[] string constant. The sqlite3_libversion() 135** function is provided for use in DLLs since DLL users usually do not have 136** direct access to string constants within the DLL. ^The 137** sqlite3_libversion_number() function returns an integer equal to 138** [SQLITE_VERSION_NUMBER]. ^The sqlite3_sourceid() function returns 139** a pointer to a string constant whose value is the same as the 140** [SQLITE_SOURCE_ID] C preprocessor macro. 141** 142** See also: [sqlite_version()] and [sqlite_source_id()]. 143*/ 144SQLITE_API SQLITE_EXTERN const char sqlite3_version[]; 145SQLITE_API const char *sqlite3_libversion(void); 146SQLITE_API const char *sqlite3_sourceid(void); 147SQLITE_API int sqlite3_libversion_number(void); 148 149/* 150** CAPI3REF: Run-Time Library Compilation Options Diagnostics 151** 152** ^The sqlite3_compileoption_used() function returns 0 or 1 153** indicating whether the specified option was defined at 154** compile time. ^The SQLITE_ prefix may be omitted from the 155** option name passed to sqlite3_compileoption_used(). 156** 157** ^The sqlite3_compileoption_get() function allows iterating 158** over the list of options that were defined at compile time by 159** returning the N-th compile time option string. ^If N is out of range, 160** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_ 161** prefix is omitted from any strings returned by 162** sqlite3_compileoption_get(). 163** 164** ^Support for the diagnostic functions sqlite3_compileoption_used() 165** and sqlite3_compileoption_get() may be omitted by specifying the 166** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time. 167** 168** See also: SQL functions [sqlite_compileoption_used()] and 169** [sqlite_compileoption_get()] and the [compile_options pragma]. 170*/ 171#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS 172SQLITE_API int sqlite3_compileoption_used(const char *zOptName); 173SQLITE_API const char *sqlite3_compileoption_get(int N); 174#endif 175 176/* 177** CAPI3REF: Test To See If The Library Is Threadsafe 178** 179** ^The sqlite3_threadsafe() function returns zero if and only if 180** SQLite was compiled mutexing code omitted due to the 181** [SQLITE_THREADSAFE] compile-time option being set to 0. 182** 183** SQLite can be compiled with or without mutexes. When 184** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes 185** are enabled and SQLite is threadsafe. When the 186** [SQLITE_THREADSAFE] macro is 0, 187** the mutexes are omitted. Without the mutexes, it is not safe 188** to use SQLite concurrently from more than one thread. 189** 190** Enabling mutexes incurs a measurable performance penalty. 191** So if speed is of utmost importance, it makes sense to disable 192** the mutexes. But for maximum safety, mutexes should be enabled. 193** ^The default behavior is for mutexes to be enabled. 194** 195** This interface can be used by an application to make sure that the 196** version of SQLite that it is linking against was compiled with 197** the desired setting of the [SQLITE_THREADSAFE] macro. 198** 199** This interface only reports on the compile-time mutex setting 200** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with 201** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but 202** can be fully or partially disabled using a call to [sqlite3_config()] 203** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], 204** or [SQLITE_CONFIG_MUTEX]. ^(The return value of the 205** sqlite3_threadsafe() function shows only the compile-time setting of 206** thread safety, not any run-time changes to that setting made by 207** sqlite3_config(). In other words, the return value from sqlite3_threadsafe() 208** is unchanged by calls to sqlite3_config().)^ 209** 210** See the [threading mode] documentation for additional information. 211*/ 212SQLITE_API int sqlite3_threadsafe(void); 213 214/* 215** CAPI3REF: Database Connection Handle 216** KEYWORDS: {database connection} {database connections} 217** 218** Each open SQLite database is represented by a pointer to an instance of 219** the opaque structure named "sqlite3". It is useful to think of an sqlite3 220** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and 221** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] 222** is its destructor. There are many other interfaces (such as 223** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 224** [sqlite3_busy_timeout()] to name but three) that are methods on an 225** sqlite3 object. 226*/ 227typedef struct sqlite3 sqlite3; 228 229/* 230** CAPI3REF: 64-Bit Integer Types 231** KEYWORDS: sqlite_int64 sqlite_uint64 232** 233** Because there is no cross-platform way to specify 64-bit integer types 234** SQLite includes typedefs for 64-bit signed and unsigned integers. 235** 236** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 237** The sqlite_int64 and sqlite_uint64 types are supported for backwards 238** compatibility only. 239** 240** ^The sqlite3_int64 and sqlite_int64 types can store integer values 241** between -9223372036854775808 and +9223372036854775807 inclusive. ^The 242** sqlite3_uint64 and sqlite_uint64 types can store integer values 243** between 0 and +18446744073709551615 inclusive. 244*/ 245#ifdef SQLITE_INT64_TYPE 246 typedef SQLITE_INT64_TYPE sqlite_int64; 247 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 248#elif defined(_MSC_VER) || defined(__BORLANDC__) 249 typedef __int64 sqlite_int64; 250 typedef unsigned __int64 sqlite_uint64; 251#else 252 typedef long long int sqlite_int64; 253 typedef unsigned long long int sqlite_uint64; 254#endif 255typedef sqlite_int64 sqlite3_int64; 256typedef sqlite_uint64 sqlite3_uint64; 257 258/* 259** If compiling for a processor that lacks floating point support, 260** substitute integer for floating-point. 261*/ 262#ifdef SQLITE_OMIT_FLOATING_POINT 263# define double sqlite3_int64 264#endif 265 266/* 267** CAPI3REF: Closing A Database Connection 268** 269** ^The sqlite3_close() routine is the destructor for the [sqlite3] object. 270** ^Calls to sqlite3_close() return SQLITE_OK if the [sqlite3] object is 271** successfully destroyed and all associated resources are deallocated. 272** 273** Applications must [sqlite3_finalize | finalize] all [prepared statements] 274** and [sqlite3_blob_close | close] all [BLOB handles] associated with 275** the [sqlite3] object prior to attempting to close the object. ^If 276** sqlite3_close() is called on a [database connection] that still has 277** outstanding [prepared statements] or [BLOB handles], then it returns 278** SQLITE_BUSY. 279** 280** ^If [sqlite3_close()] is invoked while a transaction is open, 281** the transaction is automatically rolled back. 282** 283** The C parameter to [sqlite3_close(C)] must be either a NULL 284** pointer or an [sqlite3] object pointer obtained 285** from [sqlite3_open()], [sqlite3_open16()], or 286** [sqlite3_open_v2()], and not previously closed. 287** ^Calling sqlite3_close() with a NULL pointer argument is a 288** harmless no-op. 289*/ 290SQLITE_API int sqlite3_close(sqlite3 *); 291 292/* 293** The type for a callback function. 294** This is legacy and deprecated. It is included for historical 295** compatibility and is not documented. 296*/ 297typedef int (*sqlite3_callback)(void*,int,char**, char**); 298 299/* 300** CAPI3REF: One-Step Query Execution Interface 301** 302** The sqlite3_exec() interface is a convenience wrapper around 303** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], 304** that allows an application to run multiple statements of SQL 305** without having to use a lot of C code. 306** 307** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, 308** semicolon-separate SQL statements passed into its 2nd argument, 309** in the context of the [database connection] passed in as its 1st 310** argument. ^If the callback function of the 3rd argument to 311** sqlite3_exec() is not NULL, then it is invoked for each result row 312** coming out of the evaluated SQL statements. ^The 4th argument to 313** to sqlite3_exec() is relayed through to the 1st argument of each 314** callback invocation. ^If the callback pointer to sqlite3_exec() 315** is NULL, then no callback is ever invoked and result rows are 316** ignored. 317** 318** ^If an error occurs while evaluating the SQL statements passed into 319** sqlite3_exec(), then execution of the current statement stops and 320** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() 321** is not NULL then any error message is written into memory obtained 322** from [sqlite3_malloc()] and passed back through the 5th parameter. 323** To avoid memory leaks, the application should invoke [sqlite3_free()] 324** on error message strings returned through the 5th parameter of 325** of sqlite3_exec() after the error message string is no longer needed. 326** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors 327** occur, then sqlite3_exec() sets the pointer in its 5th parameter to 328** NULL before returning. 329** 330** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() 331** routine returns SQLITE_ABORT without invoking the callback again and 332** without running any subsequent SQL statements. 333** 334** ^The 2nd argument to the sqlite3_exec() callback function is the 335** number of columns in the result. ^The 3rd argument to the sqlite3_exec() 336** callback is an array of pointers to strings obtained as if from 337** [sqlite3_column_text()], one for each column. ^If an element of a 338** result row is NULL then the corresponding string pointer for the 339** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the 340** sqlite3_exec() callback is an array of pointers to strings where each 341** entry represents the name of corresponding result column as obtained 342** from [sqlite3_column_name()]. 343** 344** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer 345** to an empty string, or a pointer that contains only whitespace and/or 346** SQL comments, then no SQL statements are evaluated and the database 347** is not changed. 348** 349** Restrictions: 350** 351** <ul> 352** <li> The application must insure that the 1st parameter to sqlite3_exec() 353** is a valid and open [database connection]. 354** <li> The application must not close [database connection] specified by 355** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running. 356** <li> The application must not modify the SQL statement text passed into 357** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running. 358** </ul> 359*/ 360SQLITE_API int sqlite3_exec( 361 sqlite3*, /* An open database */ 362 const char *sql, /* SQL to be evaluated */ 363 int (*callback)(void*,int,char**,char**), /* Callback function */ 364 void *, /* 1st argument to callback */ 365 char **errmsg /* Error msg written here */ 366); 367 368/* 369** CAPI3REF: Result Codes 370** KEYWORDS: SQLITE_OK {error code} {error codes} 371** KEYWORDS: {result code} {result codes} 372** 373** Many SQLite functions return an integer result code from the set shown 374** here in order to indicates success or failure. 375** 376** New error codes may be added in future versions of SQLite. 377** 378** See also: [SQLITE_IOERR_READ | extended result codes] 379*/ 380#define SQLITE_OK 0 /* Successful result */ 381/* beginning-of-error-codes */ 382#define SQLITE_ERROR 1 /* SQL error or missing database */ 383#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 384#define SQLITE_PERM 3 /* Access permission denied */ 385#define SQLITE_ABORT 4 /* Callback routine requested an abort */ 386#define SQLITE_BUSY 5 /* The database file is locked */ 387#define SQLITE_LOCKED 6 /* A table in the database is locked */ 388#define SQLITE_NOMEM 7 /* A malloc() failed */ 389#define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 390#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 391#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 392#define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 393#define SQLITE_NOTFOUND 12 /* NOT USED. Table or record not found */ 394#define SQLITE_FULL 13 /* Insertion failed because database is full */ 395#define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 396#define SQLITE_PROTOCOL 15 /* Database lock protocol error */ 397#define SQLITE_EMPTY 16 /* Database is empty */ 398#define SQLITE_SCHEMA 17 /* The database schema changed */ 399#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 400#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 401#define SQLITE_MISMATCH 20 /* Data type mismatch */ 402#define SQLITE_MISUSE 21 /* Library used incorrectly */ 403#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 404#define SQLITE_AUTH 23 /* Authorization denied */ 405#define SQLITE_FORMAT 24 /* Auxiliary database format error */ 406#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 407#define SQLITE_NOTADB 26 /* File opened that is not a database file */ 408#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 409#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 410/* end-of-error-codes */ 411 412/* 413** CAPI3REF: Extended Result Codes 414** KEYWORDS: {extended error code} {extended error codes} 415** KEYWORDS: {extended result code} {extended result codes} 416** 417** In its default configuration, SQLite API routines return one of 26 integer 418** [SQLITE_OK | result codes]. However, experience has shown that many of 419** these result codes are too coarse-grained. They do not provide as 420** much information about problems as programmers might like. In an effort to 421** address this, newer versions of SQLite (version 3.3.8 and later) include 422** support for additional result codes that provide more detailed information 423** about errors. The extended result codes are enabled or disabled 424** on a per database connection basis using the 425** [sqlite3_extended_result_codes()] API. 426** 427** Some of the available extended result codes are listed here. 428** One may expect the number of extended result codes will be expand 429** over time. Software that uses extended result codes should expect 430** to see new result codes in future releases of SQLite. 431** 432** The SQLITE_OK result code will never be extended. It will always 433** be exactly zero. 434*/ 435#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 436#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 437#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 438#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 439#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 440#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 441#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 442#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 443#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 444#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 445#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 446#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 447#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 448#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 449#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 450#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 451#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 452#define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) 453#define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) 454#define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) 455#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) 456#define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) 457#define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) 458 459/* 460** CAPI3REF: Flags For File Open Operations 461** 462** These bit values are intended for use in the 463** 3rd parameter to the [sqlite3_open_v2()] interface and 464** in the 4th parameter to the xOpen method of the 465** [sqlite3_vfs] object. 466*/ 467#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 468#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 469#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 470#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 471#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 472#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 473#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 474#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 475#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 476#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 477#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 478#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 479#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 480#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 481#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 482#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 483#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 484#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ 485 486/* 487** CAPI3REF: Device Characteristics 488** 489** The xDeviceCharacteristics method of the [sqlite3_io_methods] 490** object returns an integer which is a vector of the these 491** bit values expressing I/O characteristics of the mass storage 492** device that holds the file that the [sqlite3_io_methods] 493** refers to. 494** 495** The SQLITE_IOCAP_ATOMIC property means that all writes of 496** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 497** mean that writes of blocks that are nnn bytes in size and 498** are aligned to an address which is an integer multiple of 499** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 500** that when data is appended to a file, the data is appended 501** first then the size of the file is extended, never the other 502** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 503** information is written to disk in the same order as calls 504** to xWrite(). 505*/ 506#define SQLITE_IOCAP_ATOMIC 0x00000001 507#define SQLITE_IOCAP_ATOMIC512 0x00000002 508#define SQLITE_IOCAP_ATOMIC1K 0x00000004 509#define SQLITE_IOCAP_ATOMIC2K 0x00000008 510#define SQLITE_IOCAP_ATOMIC4K 0x00000010 511#define SQLITE_IOCAP_ATOMIC8K 0x00000020 512#define SQLITE_IOCAP_ATOMIC16K 0x00000040 513#define SQLITE_IOCAP_ATOMIC32K 0x00000080 514#define SQLITE_IOCAP_ATOMIC64K 0x00000100 515#define SQLITE_IOCAP_SAFE_APPEND 0x00000200 516#define SQLITE_IOCAP_SEQUENTIAL 0x00000400 517#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 518 519/* 520** CAPI3REF: File Locking Levels 521** 522** SQLite uses one of these integer values as the second 523** argument to calls it makes to the xLock() and xUnlock() methods 524** of an [sqlite3_io_methods] object. 525*/ 526#define SQLITE_LOCK_NONE 0 527#define SQLITE_LOCK_SHARED 1 528#define SQLITE_LOCK_RESERVED 2 529#define SQLITE_LOCK_PENDING 3 530#define SQLITE_LOCK_EXCLUSIVE 4 531 532/* 533** CAPI3REF: Synchronization Type Flags 534** 535** When SQLite invokes the xSync() method of an 536** [sqlite3_io_methods] object it uses a combination of 537** these integer values as the second argument. 538** 539** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 540** sync operation only needs to flush data to mass storage. Inode 541** information need not be flushed. If the lower four bits of the flag 542** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 543** If the lower four bits equal SQLITE_SYNC_FULL, that means 544** to use Mac OS X style fullsync instead of fsync(). 545*/ 546#define SQLITE_SYNC_NORMAL 0x00002 547#define SQLITE_SYNC_FULL 0x00003 548#define SQLITE_SYNC_DATAONLY 0x00010 549 550/* 551** CAPI3REF: OS Interface Open File Handle 552** 553** An [sqlite3_file] object represents an open file in the 554** [sqlite3_vfs | OS interface layer]. Individual OS interface 555** implementations will 556** want to subclass this object by appending additional fields 557** for their own use. The pMethods entry is a pointer to an 558** [sqlite3_io_methods] object that defines methods for performing 559** I/O operations on the open file. 560*/ 561typedef struct sqlite3_file sqlite3_file; 562struct sqlite3_file { 563 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 564}; 565 566/* 567** CAPI3REF: OS Interface File Virtual Methods Object 568** 569** Every file opened by the [sqlite3_vfs] xOpen method populates an 570** [sqlite3_file] object (or, more commonly, a subclass of the 571** [sqlite3_file] object) with a pointer to an instance of this object. 572** This object defines the methods used to perform various operations 573** against the open file represented by the [sqlite3_file] object. 574** 575** If the xOpen method sets the sqlite3_file.pMethods element 576** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 577** may be invoked even if the xOpen reported that it failed. The 578** only way to prevent a call to xClose following a failed xOpen 579** is for the xOpen to set the sqlite3_file.pMethods element to NULL. 580** 581** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 582** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 583** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 584** flag may be ORed in to indicate that only the data of the file 585** and not its inode needs to be synced. 586** 587** The integer values to xLock() and xUnlock() are one of 588** <ul> 589** <li> [SQLITE_LOCK_NONE], 590** <li> [SQLITE_LOCK_SHARED], 591** <li> [SQLITE_LOCK_RESERVED], 592** <li> [SQLITE_LOCK_PENDING], or 593** <li> [SQLITE_LOCK_EXCLUSIVE]. 594** </ul> 595** xLock() increases the lock. xUnlock() decreases the lock. 596** The xCheckReservedLock() method checks whether any database connection, 597** either in this process or in some other process, is holding a RESERVED, 598** PENDING, or EXCLUSIVE lock on the file. It returns true 599** if such a lock exists and false otherwise. 600** 601** The xFileControl() method is a generic interface that allows custom 602** VFS implementations to directly control an open file using the 603** [sqlite3_file_control()] interface. The second "op" argument is an 604** integer opcode. The third argument is a generic pointer intended to 605** point to a structure that may contain arguments or space in which to 606** write return values. Potential uses for xFileControl() might be 607** functions to enable blocking locks with timeouts, to change the 608** locking strategy (for example to use dot-file locks), to inquire 609** about the status of a lock, or to break stale locks. The SQLite 610** core reserves all opcodes less than 100 for its own use. 611** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available. 612** Applications that define a custom xFileControl method should use opcodes 613** greater than 100 to avoid conflicts. 614** 615** The xSectorSize() method returns the sector size of the 616** device that underlies the file. The sector size is the 617** minimum write that can be performed without disturbing 618** other bytes in the file. The xDeviceCharacteristics() 619** method returns a bit vector describing behaviors of the 620** underlying device: 621** 622** <ul> 623** <li> [SQLITE_IOCAP_ATOMIC] 624** <li> [SQLITE_IOCAP_ATOMIC512] 625** <li> [SQLITE_IOCAP_ATOMIC1K] 626** <li> [SQLITE_IOCAP_ATOMIC2K] 627** <li> [SQLITE_IOCAP_ATOMIC4K] 628** <li> [SQLITE_IOCAP_ATOMIC8K] 629** <li> [SQLITE_IOCAP_ATOMIC16K] 630** <li> [SQLITE_IOCAP_ATOMIC32K] 631** <li> [SQLITE_IOCAP_ATOMIC64K] 632** <li> [SQLITE_IOCAP_SAFE_APPEND] 633** <li> [SQLITE_IOCAP_SEQUENTIAL] 634** </ul> 635** 636** The SQLITE_IOCAP_ATOMIC property means that all writes of 637** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 638** mean that writes of blocks that are nnn bytes in size and 639** are aligned to an address which is an integer multiple of 640** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 641** that when data is appended to a file, the data is appended 642** first then the size of the file is extended, never the other 643** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 644** information is written to disk in the same order as calls 645** to xWrite(). 646** 647** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 648** in the unread portions of the buffer with zeros. A VFS that 649** fails to zero-fill short reads might seem to work. However, 650** failure to zero-fill short reads will eventually lead to 651** database corruption. 652*/ 653typedef struct sqlite3_io_methods sqlite3_io_methods; 654struct sqlite3_io_methods { 655 int iVersion; 656 int (*xClose)(sqlite3_file*); 657 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 658 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 659 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 660 int (*xSync)(sqlite3_file*, int flags); 661 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 662 int (*xLock)(sqlite3_file*, int); 663 int (*xUnlock)(sqlite3_file*, int); 664 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 665 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 666 int (*xSectorSize)(sqlite3_file*); 667 int (*xDeviceCharacteristics)(sqlite3_file*); 668 /* Methods above are valid for version 1 */ 669 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 670 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 671 void (*xShmBarrier)(sqlite3_file*); 672 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); 673 /* Methods above are valid for version 2 */ 674 /* Additional methods may be added in future releases */ 675}; 676 677/* 678** CAPI3REF: Standard File Control Opcodes 679** 680** These integer constants are opcodes for the xFileControl method 681** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 682** interface. 683** 684** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 685** opcode causes the xFileControl method to write the current state of 686** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 687** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 688** into an integer that the pArg argument points to. This capability 689** is used during testing and only needs to be supported when SQLITE_TEST 690** is defined. 691** 692** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 693** layer a hint of how large the database file will grow to be during the 694** current transaction. This hint is not guaranteed to be accurate but it 695** is often close. The underlying VFS might choose to preallocate database 696** file space based on this hint in order to help writes to the database 697** file run faster. 698** 699** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 700** extends and truncates the database file in chunks of a size specified 701** by the user. The fourth argument to [sqlite3_file_control()] should 702** point to an integer (type int) containing the new chunk-size to use 703** for the nominated database. Allocating database file space in large 704** chunks (say 1MB at a time), may reduce file-system fragmentation and 705** improve performance on some systems. 706*/ 707#define SQLITE_FCNTL_LOCKSTATE 1 708#define SQLITE_GET_LOCKPROXYFILE 2 709#define SQLITE_SET_LOCKPROXYFILE 3 710#define SQLITE_LAST_ERRNO 4 711#define SQLITE_FCNTL_SIZE_HINT 5 712#define SQLITE_FCNTL_CHUNK_SIZE 6 713 714/* 715** CAPI3REF: Mutex Handle 716** 717** The mutex module within SQLite defines [sqlite3_mutex] to be an 718** abstract type for a mutex object. The SQLite core never looks 719** at the internal representation of an [sqlite3_mutex]. It only 720** deals with pointers to the [sqlite3_mutex] object. 721** 722** Mutexes are created using [sqlite3_mutex_alloc()]. 723*/ 724typedef struct sqlite3_mutex sqlite3_mutex; 725 726/* 727** CAPI3REF: OS Interface Object 728** 729** An instance of the sqlite3_vfs object defines the interface between 730** the SQLite core and the underlying operating system. The "vfs" 731** in the name of the object stands for "virtual file system". 732** 733** The value of the iVersion field is initially 1 but may be larger in 734** future versions of SQLite. Additional fields may be appended to this 735** object when the iVersion value is increased. Note that the structure 736** of the sqlite3_vfs object changes in the transaction between 737** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 738** modified. 739** 740** The szOsFile field is the size of the subclassed [sqlite3_file] 741** structure used by this VFS. mxPathname is the maximum length of 742** a pathname in this VFS. 743** 744** Registered sqlite3_vfs objects are kept on a linked list formed by 745** the pNext pointer. The [sqlite3_vfs_register()] 746** and [sqlite3_vfs_unregister()] interfaces manage this list 747** in a thread-safe way. The [sqlite3_vfs_find()] interface 748** searches the list. Neither the application code nor the VFS 749** implementation should use the pNext pointer. 750** 751** The pNext field is the only field in the sqlite3_vfs 752** structure that SQLite will ever modify. SQLite will only access 753** or modify this field while holding a particular static mutex. 754** The application should never modify anything within the sqlite3_vfs 755** object once the object has been registered. 756** 757** The zName field holds the name of the VFS module. The name must 758** be unique across all VFS modules. 759** 760** SQLite will guarantee that the zFilename parameter to xOpen 761** is either a NULL pointer or string obtained 762** from xFullPathname(). SQLite further guarantees that 763** the string will be valid and unchanged until xClose() is 764** called. Because of the previous sentence, 765** the [sqlite3_file] can safely store a pointer to the 766** filename if it needs to remember the filename for some reason. 767** If the zFilename parameter is xOpen is a NULL pointer then xOpen 768** must invent its own temporary name for the file. Whenever the 769** xFilename parameter is NULL it will also be the case that the 770** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 771** 772** The flags argument to xOpen() includes all bits set in 773** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 774** or [sqlite3_open16()] is used, then flags includes at least 775** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 776** If xOpen() opens a file read-only then it sets *pOutFlags to 777** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 778** 779** SQLite will also add one of the following flags to the xOpen() 780** call, depending on the object being opened: 781** 782** <ul> 783** <li> [SQLITE_OPEN_MAIN_DB] 784** <li> [SQLITE_OPEN_MAIN_JOURNAL] 785** <li> [SQLITE_OPEN_TEMP_DB] 786** <li> [SQLITE_OPEN_TEMP_JOURNAL] 787** <li> [SQLITE_OPEN_TRANSIENT_DB] 788** <li> [SQLITE_OPEN_SUBJOURNAL] 789** <li> [SQLITE_OPEN_MASTER_JOURNAL] 790** </ul> 791** 792** The file I/O implementation can use the object type flags to 793** change the way it deals with files. For example, an application 794** that does not care about crash recovery or rollback might make 795** the open of a journal file a no-op. Writes to this journal would 796** also be no-ops, and any attempt to read the journal would return 797** SQLITE_IOERR. Or the implementation might recognize that a database 798** file will be doing page-aligned sector reads and writes in a random 799** order and set up its I/O subsystem accordingly. 800** 801** SQLite might also add one of the following flags to the xOpen method: 802** 803** <ul> 804** <li> [SQLITE_OPEN_DELETEONCLOSE] 805** <li> [SQLITE_OPEN_EXCLUSIVE] 806** </ul> 807** 808** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 809** deleted when it is closed. The [SQLITE_OPEN_DELETEONCLOSE] 810** will be set for TEMP databases, journals and for subjournals. 811** 812** The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 813** with the [SQLITE_OPEN_CREATE] flag, which are both directly 814** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 815** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 816** SQLITE_OPEN_CREATE, is used to indicate that file should always 817** be created, and that it is an error if it already exists. 818** It is <i>not</i> used to indicate the file should be opened 819** for exclusive access. 820** 821** At least szOsFile bytes of memory are allocated by SQLite 822** to hold the [sqlite3_file] structure passed as the third 823** argument to xOpen. The xOpen method does not have to 824** allocate the structure; it should just fill it in. Note that 825** the xOpen method must set the sqlite3_file.pMethods to either 826** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 827** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 828** element will be valid after xOpen returns regardless of the success 829** or failure of the xOpen call. 830** 831** The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 832** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 833** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 834** to test whether a file is at least readable. The file can be a 835** directory. 836** 837** SQLite will always allocate at least mxPathname+1 bytes for the 838** output buffer xFullPathname. The exact size of the output buffer 839** is also passed as a parameter to both methods. If the output buffer 840** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 841** handled as a fatal error by SQLite, vfs implementations should endeavor 842** to prevent this by setting mxPathname to a sufficiently large value. 843** 844** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 845** interfaces are not strictly a part of the filesystem, but they are 846** included in the VFS structure for completeness. 847** The xRandomness() function attempts to return nBytes bytes 848** of good-quality randomness into zOut. The return value is 849** the actual number of bytes of randomness obtained. 850** The xSleep() method causes the calling thread to sleep for at 851** least the number of microseconds given. The xCurrentTime() 852** method returns a Julian Day Number for the current date and time as 853** a floating point value. 854** The xCurrentTimeInt64() method returns, as an integer, the Julian 855** Day Number multipled by 86400000 (the number of milliseconds in 856** a 24-hour day). 857** ^SQLite will use the xCurrentTimeInt64() method to get the current 858** date and time if that method is available (if iVersion is 2 or 859** greater and the function pointer is not NULL) and will fall back 860** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 861*/ 862typedef struct sqlite3_vfs sqlite3_vfs; 863struct sqlite3_vfs { 864 int iVersion; /* Structure version number (currently 2) */ 865 int szOsFile; /* Size of subclassed sqlite3_file */ 866 int mxPathname; /* Maximum file pathname length */ 867 sqlite3_vfs *pNext; /* Next registered VFS */ 868 const char *zName; /* Name of this virtual file system */ 869 void *pAppData; /* Pointer to application-specific data */ 870 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 871 int flags, int *pOutFlags); 872 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 873 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 874 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 875 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 876 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 877 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 878 void (*xDlClose)(sqlite3_vfs*, void*); 879 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 880 int (*xSleep)(sqlite3_vfs*, int microseconds); 881 int (*xCurrentTime)(sqlite3_vfs*, double*); 882 int (*xGetLastError)(sqlite3_vfs*, int, char *); 883 /* 884 ** The methods above are in version 1 of the sqlite_vfs object 885 ** definition. Those that follow are added in version 2 or later 886 */ 887 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 888 /* 889 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 890 ** New fields may be appended in figure versions. The iVersion 891 ** value will increment whenever this happens. 892 */ 893}; 894 895/* 896** CAPI3REF: Flags for the xAccess VFS method 897** 898** These integer constants can be used as the third parameter to 899** the xAccess method of an [sqlite3_vfs] object. They determine 900** what kind of permissions the xAccess method is looking for. 901** With SQLITE_ACCESS_EXISTS, the xAccess method 902** simply checks whether the file exists. 903** With SQLITE_ACCESS_READWRITE, the xAccess method 904** checks whether the named directory is both readable and writable 905** (in other words, if files can be added, removed, and renamed within 906** the directory). 907** The SQLITE_ACCESS_READWRITE constant is currently used only by the 908** [temp_store_directory pragma], though this could change in a future 909** release of SQLite. 910** With SQLITE_ACCESS_READ, the xAccess method 911** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 912** currently unused, though it might be used in a future release of 913** SQLite. 914*/ 915#define SQLITE_ACCESS_EXISTS 0 916#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 917#define SQLITE_ACCESS_READ 2 /* Unused */ 918 919/* 920** CAPI3REF: Flags for the xShmLock VFS method 921** 922** These integer constants define the various locking operations 923** allowed by the xShmLock method of [sqlite3_io_methods]. The 924** following are the only legal combinations of flags to the 925** xShmLock method: 926** 927** <ul> 928** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 929** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 930** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 931** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 932** </ul> 933** 934** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 935** was given no the corresponding lock. 936** 937** The xShmLock method can transition between unlocked and SHARED or 938** between unlocked and EXCLUSIVE. It cannot transition between SHARED 939** and EXCLUSIVE. 940*/ 941#define SQLITE_SHM_UNLOCK 1 942#define SQLITE_SHM_LOCK 2 943#define SQLITE_SHM_SHARED 4 944#define SQLITE_SHM_EXCLUSIVE 8 945 946/* 947** CAPI3REF: Maximum xShmLock index 948** 949** The xShmLock method on [sqlite3_io_methods] may use values 950** between 0 and this upper bound as its "offset" argument. 951** The SQLite core will never attempt to acquire or release a 952** lock outside of this range 953*/ 954#define SQLITE_SHM_NLOCK 8 955 956 957/* 958** CAPI3REF: Initialize The SQLite Library 959** 960** ^The sqlite3_initialize() routine initializes the 961** SQLite library. ^The sqlite3_shutdown() routine 962** deallocates any resources that were allocated by sqlite3_initialize(). 963** These routines are designed to aid in process initialization and 964** shutdown on embedded systems. Workstation applications using 965** SQLite normally do not need to invoke either of these routines. 966** 967** A call to sqlite3_initialize() is an "effective" call if it is 968** the first time sqlite3_initialize() is invoked during the lifetime of 969** the process, or if it is the first time sqlite3_initialize() is invoked 970** following a call to sqlite3_shutdown(). ^(Only an effective call 971** of sqlite3_initialize() does any initialization. All other calls 972** are harmless no-ops.)^ 973** 974** A call to sqlite3_shutdown() is an "effective" call if it is the first 975** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 976** an effective call to sqlite3_shutdown() does any deinitialization. 977** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 978** 979** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 980** is not. The sqlite3_shutdown() interface must only be called from a 981** single thread. All open [database connections] must be closed and all 982** other SQLite resources must be deallocated prior to invoking 983** sqlite3_shutdown(). 984** 985** Among other things, ^sqlite3_initialize() will invoke 986** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 987** will invoke sqlite3_os_end(). 988** 989** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 990** ^If for some reason, sqlite3_initialize() is unable to initialize 991** the library (perhaps it is unable to allocate a needed resource such 992** as a mutex) it returns an [error code] other than [SQLITE_OK]. 993** 994** ^The sqlite3_initialize() routine is called internally by many other 995** SQLite interfaces so that an application usually does not need to 996** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 997** calls sqlite3_initialize() so the SQLite library will be automatically 998** initialized when [sqlite3_open()] is called if it has not be initialized 999** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1000** compile-time option, then the automatic calls to sqlite3_initialize() 1001** are omitted and the application must call sqlite3_initialize() directly 1002** prior to using any other SQLite interface. For maximum portability, 1003** it is recommended that applications always invoke sqlite3_initialize() 1004** directly prior to using any other SQLite interface. Future releases 1005** of SQLite may require this. In other words, the behavior exhibited 1006** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1007** default behavior in some future release of SQLite. 1008** 1009** The sqlite3_os_init() routine does operating-system specific 1010** initialization of the SQLite library. The sqlite3_os_end() 1011** routine undoes the effect of sqlite3_os_init(). Typical tasks 1012** performed by these routines include allocation or deallocation 1013** of static resources, initialization of global variables, 1014** setting up a default [sqlite3_vfs] module, or setting up 1015** a default configuration using [sqlite3_config()]. 1016** 1017** The application should never invoke either sqlite3_os_init() 1018** or sqlite3_os_end() directly. The application should only invoke 1019** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1020** interface is called automatically by sqlite3_initialize() and 1021** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1022** implementations for sqlite3_os_init() and sqlite3_os_end() 1023** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1024** When [custom builds | built for other platforms] 1025** (using the [SQLITE_OS_OTHER=1] compile-time 1026** option) the application must supply a suitable implementation for 1027** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1028** implementation of sqlite3_os_init() or sqlite3_os_end() 1029** must return [SQLITE_OK] on success and some other [error code] upon 1030** failure. 1031*/ 1032SQLITE_API int sqlite3_initialize(void); 1033SQLITE_API int sqlite3_shutdown(void); 1034SQLITE_API int sqlite3_os_init(void); 1035SQLITE_API int sqlite3_os_end(void); 1036 1037/* 1038** CAPI3REF: Configuring The SQLite Library 1039** 1040** The sqlite3_config() interface is used to make global configuration 1041** changes to SQLite in order to tune SQLite to the specific needs of 1042** the application. The default configuration is recommended for most 1043** applications and so this routine is usually not necessary. It is 1044** provided to support rare applications with unusual needs. 1045** 1046** The sqlite3_config() interface is not threadsafe. The application 1047** must insure that no other SQLite interfaces are invoked by other 1048** threads while sqlite3_config() is running. Furthermore, sqlite3_config() 1049** may only be invoked prior to library initialization using 1050** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1051** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1052** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1053** Note, however, that ^sqlite3_config() can be called as part of the 1054** implementation of an application-defined [sqlite3_os_init()]. 1055** 1056** The first argument to sqlite3_config() is an integer 1057** [SQLITE_CONFIG_SINGLETHREAD | configuration option] that determines 1058** what property of SQLite is to be configured. Subsequent arguments 1059** vary depending on the [SQLITE_CONFIG_SINGLETHREAD | configuration option] 1060** in the first argument. 1061** 1062** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1063** ^If the option is unknown or SQLite is unable to set the option 1064** then this routine returns a non-zero [error code]. 1065*/ 1066SQLITE_API int sqlite3_config(int, ...); 1067 1068/* 1069** CAPI3REF: Configure database connections 1070** 1071** The sqlite3_db_config() interface is used to make configuration 1072** changes to a [database connection]. The interface is similar to 1073** [sqlite3_config()] except that the changes apply to a single 1074** [database connection] (specified in the first argument). The 1075** sqlite3_db_config() interface should only be used immediately after 1076** the database connection is created using [sqlite3_open()], 1077** [sqlite3_open16()], or [sqlite3_open_v2()]. 1078** 1079** The second argument to sqlite3_db_config(D,V,...) is the 1080** configuration verb - an integer code that indicates what 1081** aspect of the [database connection] is being configured. 1082** The only choice for this value is [SQLITE_DBCONFIG_LOOKASIDE]. 1083** New verbs are likely to be added in future releases of SQLite. 1084** Additional arguments depend on the verb. 1085** 1086** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1087** the call is considered successful. 1088*/ 1089SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...); 1090 1091/* 1092** CAPI3REF: Memory Allocation Routines 1093** 1094** An instance of this object defines the interface between SQLite 1095** and low-level memory allocation routines. 1096** 1097** This object is used in only one place in the SQLite interface. 1098** A pointer to an instance of this object is the argument to 1099** [sqlite3_config()] when the configuration option is 1100** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1101** By creating an instance of this object 1102** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1103** during configuration, an application can specify an alternative 1104** memory allocation subsystem for SQLite to use for all of its 1105** dynamic memory needs. 1106** 1107** Note that SQLite comes with several [built-in memory allocators] 1108** that are perfectly adequate for the overwhelming majority of applications 1109** and that this object is only useful to a tiny minority of applications 1110** with specialized memory allocation requirements. This object is 1111** also used during testing of SQLite in order to specify an alternative 1112** memory allocator that simulates memory out-of-memory conditions in 1113** order to verify that SQLite recovers gracefully from such 1114** conditions. 1115** 1116** The xMalloc and xFree methods must work like the 1117** malloc() and free() functions from the standard C library. 1118** The xRealloc method must work like realloc() from the standard C library 1119** with the exception that if the second argument to xRealloc is zero, 1120** xRealloc must be a no-op - it must not perform any allocation or 1121** deallocation. ^SQLite guarantees that the second argument to 1122** xRealloc is always a value returned by a prior call to xRoundup. 1123** And so in cases where xRoundup always returns a positive number, 1124** xRealloc can perform exactly as the standard library realloc() and 1125** still be in compliance with this specification. 1126** 1127** xSize should return the allocated size of a memory allocation 1128** previously obtained from xMalloc or xRealloc. The allocated size 1129** is always at least as big as the requested size but may be larger. 1130** 1131** The xRoundup method returns what would be the allocated size of 1132** a memory allocation given a particular requested size. Most memory 1133** allocators round up memory allocations at least to the next multiple 1134** of 8. Some allocators round up to a larger multiple or to a power of 2. 1135** Every memory allocation request coming in through [sqlite3_malloc()] 1136** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1137** that causes the corresponding memory allocation to fail. 1138** 1139** The xInit method initializes the memory allocator. (For example, 1140** it might allocate any require mutexes or initialize internal data 1141** structures. The xShutdown method is invoked (indirectly) by 1142** [sqlite3_shutdown()] and should deallocate any resources acquired 1143** by xInit. The pAppData pointer is used as the only parameter to 1144** xInit and xShutdown. 1145** 1146** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1147** the xInit method, so the xInit method need not be threadsafe. The 1148** xShutdown method is only called from [sqlite3_shutdown()] so it does 1149** not need to be threadsafe either. For all other methods, SQLite 1150** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1151** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1152** it is by default) and so the methods are automatically serialized. 1153** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1154** methods must be threadsafe or else make their own arrangements for 1155** serialization. 1156** 1157** SQLite will never invoke xInit() more than once without an intervening 1158** call to xShutdown(). 1159*/ 1160typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1161struct sqlite3_mem_methods { 1162 void *(*xMalloc)(int); /* Memory allocation function */ 1163 void (*xFree)(void*); /* Free a prior allocation */ 1164 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1165 int (*xSize)(void*); /* Return the size of an allocation */ 1166 int (*xRoundup)(int); /* Round up request size to allocation size */ 1167 int (*xInit)(void*); /* Initialize the memory allocator */ 1168 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1169 void *pAppData; /* Argument to xInit() and xShutdown() */ 1170}; 1171 1172/* 1173** CAPI3REF: Configuration Options 1174** 1175** These constants are the available integer configuration options that 1176** can be passed as the first argument to the [sqlite3_config()] interface. 1177** 1178** New configuration options may be added in future releases of SQLite. 1179** Existing configuration options might be discontinued. Applications 1180** should check the return code from [sqlite3_config()] to make sure that 1181** the call worked. The [sqlite3_config()] interface will return a 1182** non-zero [error code] if a discontinued or unsupported configuration option 1183** is invoked. 1184** 1185** <dl> 1186** <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1187** <dd>There are no arguments to this option. ^This option sets the 1188** [threading mode] to Single-thread. In other words, it disables 1189** all mutexing and puts SQLite into a mode where it can only be used 1190** by a single thread. ^If SQLite is compiled with 1191** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1192** it is not possible to change the [threading mode] from its default 1193** value of Single-thread and so [sqlite3_config()] will return 1194** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1195** configuration option.</dd> 1196** 1197** <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1198** <dd>There are no arguments to this option. ^This option sets the 1199** [threading mode] to Multi-thread. In other words, it disables 1200** mutexing on [database connection] and [prepared statement] objects. 1201** The application is responsible for serializing access to 1202** [database connections] and [prepared statements]. But other mutexes 1203** are enabled so that SQLite will be safe to use in a multi-threaded 1204** environment as long as no two threads attempt to use the same 1205** [database connection] at the same time. ^If SQLite is compiled with 1206** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1207** it is not possible to set the Multi-thread [threading mode] and 1208** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1209** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1210** 1211** <dt>SQLITE_CONFIG_SERIALIZED</dt> 1212** <dd>There are no arguments to this option. ^This option sets the 1213** [threading mode] to Serialized. In other words, this option enables 1214** all mutexes including the recursive 1215** mutexes on [database connection] and [prepared statement] objects. 1216** In this mode (which is the default when SQLite is compiled with 1217** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1218** to [database connections] and [prepared statements] so that the 1219** application is free to use the same [database connection] or the 1220** same [prepared statement] in different threads at the same time. 1221** ^If SQLite is compiled with 1222** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1223** it is not possible to set the Serialized [threading mode] and 1224** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1225** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1226** 1227** <dt>SQLITE_CONFIG_MALLOC</dt> 1228** <dd> ^(This option takes a single argument which is a pointer to an 1229** instance of the [sqlite3_mem_methods] structure. The argument specifies 1230** alternative low-level memory allocation routines to be used in place of 1231** the memory allocation routines built into SQLite.)^ ^SQLite makes 1232** its own private copy of the content of the [sqlite3_mem_methods] structure 1233** before the [sqlite3_config()] call returns.</dd> 1234** 1235** <dt>SQLITE_CONFIG_GETMALLOC</dt> 1236** <dd> ^(This option takes a single argument which is a pointer to an 1237** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods] 1238** structure is filled with the currently defined memory allocation routines.)^ 1239** This option can be used to overload the default memory allocation 1240** routines with a wrapper that simulations memory allocation failure or 1241** tracks memory usage, for example. </dd> 1242** 1243** <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1244** <dd> ^This option takes single argument of type int, interpreted as a 1245** boolean, which enables or disables the collection of memory allocation 1246** statistics. ^(When memory allocation statistics are disabled, the 1247** following SQLite interfaces become non-operational: 1248** <ul> 1249** <li> [sqlite3_memory_used()] 1250** <li> [sqlite3_memory_highwater()] 1251** <li> [sqlite3_soft_heap_limit()] 1252** <li> [sqlite3_status()] 1253** </ul>)^ 1254** ^Memory allocation statistics are enabled by default unless SQLite is 1255** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1256** allocation statistics are disabled by default. 1257** </dd> 1258** 1259** <dt>SQLITE_CONFIG_SCRATCH</dt> 1260** <dd> ^This option specifies a static memory buffer that SQLite can use for 1261** scratch memory. There are three arguments: A pointer an 8-byte 1262** aligned memory buffer from which the scrach allocations will be 1263** drawn, the size of each scratch allocation (sz), 1264** and the maximum number of scratch allocations (N). The sz 1265** argument must be a multiple of 16. The sz parameter should be a few bytes 1266** larger than the actual scratch space required due to internal overhead. 1267** The first argument must be a pointer to an 8-byte aligned buffer 1268** of at least sz*N bytes of memory. 1269** ^SQLite will use no more than one scratch buffer per thread. So 1270** N should be set to the expected maximum number of threads. ^SQLite will 1271** never require a scratch buffer that is more than 6 times the database 1272** page size. ^If SQLite needs needs additional scratch memory beyond 1273** what is provided by this configuration option, then 1274** [sqlite3_malloc()] will be used to obtain the memory needed.</dd> 1275** 1276** <dt>SQLITE_CONFIG_PAGECACHE</dt> 1277** <dd> ^This option specifies a static memory buffer that SQLite can use for 1278** the database page cache with the default page cache implemenation. 1279** This configuration should not be used if an application-define page 1280** cache implementation is loaded using the SQLITE_CONFIG_PCACHE option. 1281** There are three arguments to this option: A pointer to 8-byte aligned 1282** memory, the size of each page buffer (sz), and the number of pages (N). 1283** The sz argument should be the size of the largest database page 1284** (a power of two between 512 and 32768) plus a little extra for each 1285** page header. ^The page header size is 20 to 40 bytes depending on 1286** the host architecture. ^It is harmless, apart from the wasted memory, 1287** to make sz a little too large. The first 1288** argument should point to an allocation of at least sz*N bytes of memory. 1289** ^SQLite will use the memory provided by the first argument to satisfy its 1290** memory needs for the first N pages that it adds to cache. ^If additional 1291** page cache memory is needed beyond what is provided by this option, then 1292** SQLite goes to [sqlite3_malloc()] for the additional storage space. 1293** ^The implementation might use one or more of the N buffers to hold 1294** memory accounting information. The pointer in the first argument must 1295** be aligned to an 8-byte boundary or subsequent behavior of SQLite 1296** will be undefined.</dd> 1297** 1298** <dt>SQLITE_CONFIG_HEAP</dt> 1299** <dd> ^This option specifies a static memory buffer that SQLite will use 1300** for all of its dynamic memory allocation needs beyond those provided 1301** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE]. 1302** There are three arguments: An 8-byte aligned pointer to the memory, 1303** the number of bytes in the memory buffer, and the minimum allocation size. 1304** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1305** to using its default memory allocator (the system malloc() implementation), 1306** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1307** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or 1308** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory 1309** allocator is engaged to handle all of SQLites memory allocation needs. 1310** The first pointer (the memory pointer) must be aligned to an 8-byte 1311** boundary or subsequent behavior of SQLite will be undefined.</dd> 1312** 1313** <dt>SQLITE_CONFIG_MUTEX</dt> 1314** <dd> ^(This option takes a single argument which is a pointer to an 1315** instance of the [sqlite3_mutex_methods] structure. The argument specifies 1316** alternative low-level mutex routines to be used in place 1317** the mutex routines built into SQLite.)^ ^SQLite makes a copy of the 1318** content of the [sqlite3_mutex_methods] structure before the call to 1319** [sqlite3_config()] returns. ^If SQLite is compiled with 1320** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1321** the entire mutexing subsystem is omitted from the build and hence calls to 1322** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1323** return [SQLITE_ERROR].</dd> 1324** 1325** <dt>SQLITE_CONFIG_GETMUTEX</dt> 1326** <dd> ^(This option takes a single argument which is a pointer to an 1327** instance of the [sqlite3_mutex_methods] structure. The 1328** [sqlite3_mutex_methods] 1329** structure is filled with the currently defined mutex routines.)^ 1330** This option can be used to overload the default mutex allocation 1331** routines with a wrapper used to track mutex usage for performance 1332** profiling or testing, for example. ^If SQLite is compiled with 1333** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1334** the entire mutexing subsystem is omitted from the build and hence calls to 1335** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1336** return [SQLITE_ERROR].</dd> 1337** 1338** <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1339** <dd> ^(This option takes two arguments that determine the default 1340** memory allocation for the lookaside memory allocator on each 1341** [database connection]. The first argument is the 1342** size of each lookaside buffer slot and the second is the number of 1343** slots allocated to each database connection.)^ ^(This option sets the 1344** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1345** verb to [sqlite3_db_config()] can be used to change the lookaside 1346** configuration on individual connections.)^ </dd> 1347** 1348** <dt>SQLITE_CONFIG_PCACHE</dt> 1349** <dd> ^(This option takes a single argument which is a pointer to 1350** an [sqlite3_pcache_methods] object. This object specifies the interface 1351** to a custom page cache implementation.)^ ^SQLite makes a copy of the 1352** object and uses it for page cache memory allocations.</dd> 1353** 1354** <dt>SQLITE_CONFIG_GETPCACHE</dt> 1355** <dd> ^(This option takes a single argument which is a pointer to an 1356** [sqlite3_pcache_methods] object. SQLite copies of the current 1357** page cache implementation into that object.)^ </dd> 1358** 1359** <dt>SQLITE_CONFIG_LOG</dt> 1360** <dd> ^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1361** function with a call signature of void(*)(void*,int,const char*), 1362** and a pointer to void. ^If the function pointer is not NULL, it is 1363** invoked by [sqlite3_log()] to process each logging event. ^If the 1364** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1365** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1366** passed through as the first parameter to the application-defined logger 1367** function whenever that function is invoked. ^The second parameter to 1368** the logger function is a copy of the first parameter to the corresponding 1369** [sqlite3_log()] call and is intended to be a [result code] or an 1370** [extended result code]. ^The third parameter passed to the logger is 1371** log message after formatting via [sqlite3_snprintf()]. 1372** The SQLite logging interface is not reentrant; the logger function 1373** supplied by the application must not invoke any SQLite interface. 1374** In a multi-threaded application, the application-defined logger 1375** function must be threadsafe. </dd> 1376** 1377** </dl> 1378*/ 1379#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1380#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1381#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1382#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1383#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1384#define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1385#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1386#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1387#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1388#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1389#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1390/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1391#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1392#define SQLITE_CONFIG_PCACHE 14 /* sqlite3_pcache_methods* */ 1393#define SQLITE_CONFIG_GETPCACHE 15 /* sqlite3_pcache_methods* */ 1394#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1395 1396/* 1397** CAPI3REF: Database Connection Configuration Options 1398** 1399** These constants are the available integer configuration options that 1400** can be passed as the second argument to the [sqlite3_db_config()] interface. 1401** 1402** New configuration options may be added in future releases of SQLite. 1403** Existing configuration options might be discontinued. Applications 1404** should check the return code from [sqlite3_db_config()] to make sure that 1405** the call worked. ^The [sqlite3_db_config()] interface will return a 1406** non-zero [error code] if a discontinued or unsupported configuration option 1407** is invoked. 1408** 1409** <dl> 1410** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1411** <dd> ^This option takes three additional arguments that determine the 1412** [lookaside memory allocator] configuration for the [database connection]. 1413** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1414** pointer to an memory buffer to use for lookaside memory. 1415** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1416** may be NULL in which case SQLite will allocate the 1417** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1418** size of each lookaside buffer slot. ^The third argument is the number of 1419** slots. The size of the buffer in the first argument must be greater than 1420** or equal to the product of the second and third arguments. The buffer 1421** must be aligned to an 8-byte boundary. ^If the second argument to 1422** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1423** rounded down to the next smaller 1424** multiple of 8. See also: [SQLITE_CONFIG_LOOKASIDE]</dd> 1425** 1426** </dl> 1427*/ 1428#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 1429 1430 1431/* 1432** CAPI3REF: Enable Or Disable Extended Result Codes 1433** 1434** ^The sqlite3_extended_result_codes() routine enables or disables the 1435** [extended result codes] feature of SQLite. ^The extended result 1436** codes are disabled by default for historical compatibility. 1437*/ 1438SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff); 1439 1440/* 1441** CAPI3REF: Last Insert Rowid 1442** 1443** ^Each entry in an SQLite table has a unique 64-bit signed 1444** integer key called the [ROWID | "rowid"]. ^The rowid is always available 1445** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 1446** names are not also used by explicitly declared columns. ^If 1447** the table has a column of type [INTEGER PRIMARY KEY] then that column 1448** is another alias for the rowid. 1449** 1450** ^This routine returns the [rowid] of the most recent 1451** successful [INSERT] into the database from the [database connection] 1452** in the first argument. ^If no successful [INSERT]s 1453** have ever occurred on that database connection, zero is returned. 1454** 1455** ^(If an [INSERT] occurs within a trigger, then the [rowid] of the inserted 1456** row is returned by this routine as long as the trigger is running. 1457** But once the trigger terminates, the value returned by this routine 1458** reverts to the last value inserted before the trigger fired.)^ 1459** 1460** ^An [INSERT] that fails due to a constraint violation is not a 1461** successful [INSERT] and does not change the value returned by this 1462** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 1463** and INSERT OR ABORT make no changes to the return value of this 1464** routine when their insertion fails. ^(When INSERT OR REPLACE 1465** encounters a constraint violation, it does not fail. The 1466** INSERT continues to completion after deleting rows that caused 1467** the constraint problem so INSERT OR REPLACE will always change 1468** the return value of this interface.)^ 1469** 1470** ^For the purposes of this routine, an [INSERT] is considered to 1471** be successful even if it is subsequently rolled back. 1472** 1473** This function is accessible to SQL statements via the 1474** [last_insert_rowid() SQL function]. 1475** 1476** If a separate thread performs a new [INSERT] on the same 1477** database connection while the [sqlite3_last_insert_rowid()] 1478** function is running and thus changes the last insert [rowid], 1479** then the value returned by [sqlite3_last_insert_rowid()] is 1480** unpredictable and might not equal either the old or the new 1481** last insert [rowid]. 1482*/ 1483SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 1484 1485/* 1486** CAPI3REF: Count The Number Of Rows Modified 1487** 1488** ^This function returns the number of database rows that were changed 1489** or inserted or deleted by the most recently completed SQL statement 1490** on the [database connection] specified by the first parameter. 1491** ^(Only changes that are directly specified by the [INSERT], [UPDATE], 1492** or [DELETE] statement are counted. Auxiliary changes caused by 1493** triggers or [foreign key actions] are not counted.)^ Use the 1494** [sqlite3_total_changes()] function to find the total number of changes 1495** including changes caused by triggers and foreign key actions. 1496** 1497** ^Changes to a view that are simulated by an [INSTEAD OF trigger] 1498** are not counted. Only real table changes are counted. 1499** 1500** ^(A "row change" is a change to a single row of a single table 1501** caused by an INSERT, DELETE, or UPDATE statement. Rows that 1502** are changed as side effects of [REPLACE] constraint resolution, 1503** rollback, ABORT processing, [DROP TABLE], or by any other 1504** mechanisms do not count as direct row changes.)^ 1505** 1506** A "trigger context" is a scope of execution that begins and 1507** ends with the script of a [CREATE TRIGGER | trigger]. 1508** Most SQL statements are 1509** evaluated outside of any trigger. This is the "top level" 1510** trigger context. If a trigger fires from the top level, a 1511** new trigger context is entered for the duration of that one 1512** trigger. Subtriggers create subcontexts for their duration. 1513** 1514** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does 1515** not create a new trigger context. 1516** 1517** ^This function returns the number of direct row changes in the 1518** most recent INSERT, UPDATE, or DELETE statement within the same 1519** trigger context. 1520** 1521** ^Thus, when called from the top level, this function returns the 1522** number of changes in the most recent INSERT, UPDATE, or DELETE 1523** that also occurred at the top level. ^(Within the body of a trigger, 1524** the sqlite3_changes() interface can be called to find the number of 1525** changes in the most recently completed INSERT, UPDATE, or DELETE 1526** statement within the body of the same trigger. 1527** However, the number returned does not include changes 1528** caused by subtriggers since those have their own context.)^ 1529** 1530** See also the [sqlite3_total_changes()] interface, the 1531** [count_changes pragma], and the [changes() SQL function]. 1532** 1533** If a separate thread makes changes on the same database connection 1534** while [sqlite3_changes()] is running then the value returned 1535** is unpredictable and not meaningful. 1536*/ 1537SQLITE_API int sqlite3_changes(sqlite3*); 1538 1539/* 1540** CAPI3REF: Total Number Of Rows Modified 1541** 1542** ^This function returns the number of row changes caused by [INSERT], 1543** [UPDATE] or [DELETE] statements since the [database connection] was opened. 1544** ^(The count returned by sqlite3_total_changes() includes all changes 1545** from all [CREATE TRIGGER | trigger] contexts and changes made by 1546** [foreign key actions]. However, 1547** the count does not include changes used to implement [REPLACE] constraints, 1548** do rollbacks or ABORT processing, or [DROP TABLE] processing. The 1549** count does not include rows of views that fire an [INSTEAD OF trigger], 1550** though if the INSTEAD OF trigger makes changes of its own, those changes 1551** are counted.)^ 1552** ^The sqlite3_total_changes() function counts the changes as soon as 1553** the statement that makes them is completed (when the statement handle 1554** is passed to [sqlite3_reset()] or [sqlite3_finalize()]). 1555** 1556** See also the [sqlite3_changes()] interface, the 1557** [count_changes pragma], and the [total_changes() SQL function]. 1558** 1559** If a separate thread makes changes on the same database connection 1560** while [sqlite3_total_changes()] is running then the value 1561** returned is unpredictable and not meaningful. 1562*/ 1563SQLITE_API int sqlite3_total_changes(sqlite3*); 1564 1565/* 1566** CAPI3REF: Interrupt A Long-Running Query 1567** 1568** ^This function causes any pending database operation to abort and 1569** return at its earliest opportunity. This routine is typically 1570** called in response to a user action such as pressing "Cancel" 1571** or Ctrl-C where the user wants a long query operation to halt 1572** immediately. 1573** 1574** ^It is safe to call this routine from a thread different from the 1575** thread that is currently running the database operation. But it 1576** is not safe to call this routine with a [database connection] that 1577** is closed or might close before sqlite3_interrupt() returns. 1578** 1579** ^If an SQL operation is very nearly finished at the time when 1580** sqlite3_interrupt() is called, then it might not have an opportunity 1581** to be interrupted and might continue to completion. 1582** 1583** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 1584** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 1585** that is inside an explicit transaction, then the entire transaction 1586** will be rolled back automatically. 1587** 1588** ^The sqlite3_interrupt(D) call is in effect until all currently running 1589** SQL statements on [database connection] D complete. ^Any new SQL statements 1590** that are started after the sqlite3_interrupt() call and before the 1591** running statements reaches zero are interrupted as if they had been 1592** running prior to the sqlite3_interrupt() call. ^New SQL statements 1593** that are started after the running statement count reaches zero are 1594** not effected by the sqlite3_interrupt(). 1595** ^A call to sqlite3_interrupt(D) that occurs when there are no running 1596** SQL statements is a no-op and has no effect on SQL statements 1597** that are started after the sqlite3_interrupt() call returns. 1598** 1599** If the database connection closes while [sqlite3_interrupt()] 1600** is running then bad things will likely happen. 1601*/ 1602SQLITE_API void sqlite3_interrupt(sqlite3*); 1603 1604/* 1605** CAPI3REF: Determine If An SQL Statement Is Complete 1606** 1607** These routines are useful during command-line input to determine if the 1608** currently entered text seems to form a complete SQL statement or 1609** if additional input is needed before sending the text into 1610** SQLite for parsing. ^These routines return 1 if the input string 1611** appears to be a complete SQL statement. ^A statement is judged to be 1612** complete if it ends with a semicolon token and is not a prefix of a 1613** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 1614** string literals or quoted identifier names or comments are not 1615** independent tokens (they are part of the token in which they are 1616** embedded) and thus do not count as a statement terminator. ^Whitespace 1617** and comments that follow the final semicolon are ignored. 1618** 1619** ^These routines return 0 if the statement is incomplete. ^If a 1620** memory allocation fails, then SQLITE_NOMEM is returned. 1621** 1622** ^These routines do not parse the SQL statements thus 1623** will not detect syntactically incorrect SQL. 1624** 1625** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 1626** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 1627** automatically by sqlite3_complete16(). If that initialization fails, 1628** then the return value from sqlite3_complete16() will be non-zero 1629** regardless of whether or not the input SQL is complete.)^ 1630** 1631** The input to [sqlite3_complete()] must be a zero-terminated 1632** UTF-8 string. 1633** 1634** The input to [sqlite3_complete16()] must be a zero-terminated 1635** UTF-16 string in native byte order. 1636*/ 1637SQLITE_API int sqlite3_complete(const char *sql); 1638SQLITE_API int sqlite3_complete16(const void *sql); 1639 1640/* 1641** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 1642** 1643** ^This routine sets a callback function that might be invoked whenever 1644** an attempt is made to open a database table that another thread 1645** or process has locked. 1646** 1647** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] 1648** is returned immediately upon encountering the lock. ^If the busy callback 1649** is not NULL, then the callback might be invoked with two arguments. 1650** 1651** ^The first argument to the busy handler is a copy of the void* pointer which 1652** is the third argument to sqlite3_busy_handler(). ^The second argument to 1653** the busy handler callback is the number of times that the busy handler has 1654** been invoked for this locking event. ^If the 1655** busy callback returns 0, then no additional attempts are made to 1656** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned. 1657** ^If the callback returns non-zero, then another attempt 1658** is made to open the database for reading and the cycle repeats. 1659** 1660** The presence of a busy handler does not guarantee that it will be invoked 1661** when there is lock contention. ^If SQLite determines that invoking the busy 1662** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 1663** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler. 1664** Consider a scenario where one process is holding a read lock that 1665** it is trying to promote to a reserved lock and 1666** a second process is holding a reserved lock that it is trying 1667** to promote to an exclusive lock. The first process cannot proceed 1668** because it is blocked by the second and the second process cannot 1669** proceed because it is blocked by the first. If both processes 1670** invoke the busy handlers, neither will make any progress. Therefore, 1671** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 1672** will induce the first process to release its read lock and allow 1673** the second process to proceed. 1674** 1675** ^The default busy callback is NULL. 1676** 1677** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED] 1678** when SQLite is in the middle of a large transaction where all the 1679** changes will not fit into the in-memory cache. SQLite will 1680** already hold a RESERVED lock on the database file, but it needs 1681** to promote this lock to EXCLUSIVE so that it can spill cache 1682** pages into the database file without harm to concurrent 1683** readers. ^If it is unable to promote the lock, then the in-memory 1684** cache will be left in an inconsistent state and so the error 1685** code is promoted from the relatively benign [SQLITE_BUSY] to 1686** the more severe [SQLITE_IOERR_BLOCKED]. ^This error code promotion 1687** forces an automatic rollback of the changes. See the 1688** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError"> 1689** CorruptionFollowingBusyError</a> wiki page for a discussion of why 1690** this is important. 1691** 1692** ^(There can only be a single busy handler defined for each 1693** [database connection]. Setting a new busy handler clears any 1694** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 1695** will also set or clear the busy handler. 1696** 1697** The busy callback should not take any actions which modify the 1698** database connection that invoked the busy handler. Any such actions 1699** result in undefined behavior. 1700** 1701** A busy handler must not close the database connection 1702** or [prepared statement] that invoked the busy handler. 1703*/ 1704SQLITE_API int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*); 1705 1706/* 1707** CAPI3REF: Set A Busy Timeout 1708** 1709** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 1710** for a specified amount of time when a table is locked. ^The handler 1711** will sleep multiple times until at least "ms" milliseconds of sleeping 1712** have accumulated. ^After at least "ms" milliseconds of sleeping, 1713** the handler returns 0 which causes [sqlite3_step()] to return 1714** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]. 1715** 1716** ^Calling this routine with an argument less than or equal to zero 1717** turns off all busy handlers. 1718** 1719** ^(There can only be a single busy handler for a particular 1720** [database connection] any any given moment. If another busy handler 1721** was defined (using [sqlite3_busy_handler()]) prior to calling 1722** this routine, that other busy handler is cleared.)^ 1723*/ 1724SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms); 1725 1726/* 1727** CAPI3REF: Convenience Routines For Running Queries 1728** 1729** Definition: A <b>result table</b> is memory data structure created by the 1730** [sqlite3_get_table()] interface. A result table records the 1731** complete query results from one or more queries. 1732** 1733** The table conceptually has a number of rows and columns. But 1734** these numbers are not part of the result table itself. These 1735** numbers are obtained separately. Let N be the number of rows 1736** and M be the number of columns. 1737** 1738** A result table is an array of pointers to zero-terminated UTF-8 strings. 1739** There are (N+1)*M elements in the array. The first M pointers point 1740** to zero-terminated strings that contain the names of the columns. 1741** The remaining entries all point to query results. NULL values result 1742** in NULL pointers. All other values are in their UTF-8 zero-terminated 1743** string representation as returned by [sqlite3_column_text()]. 1744** 1745** A result table might consist of one or more memory allocations. 1746** It is not safe to pass a result table directly to [sqlite3_free()]. 1747** A result table should be deallocated using [sqlite3_free_table()]. 1748** 1749** As an example of the result table format, suppose a query result 1750** is as follows: 1751** 1752** <blockquote><pre> 1753** Name | Age 1754** ----------------------- 1755** Alice | 43 1756** Bob | 28 1757** Cindy | 21 1758** </pre></blockquote> 1759** 1760** There are two column (M==2) and three rows (N==3). Thus the 1761** result table has 8 entries. Suppose the result table is stored 1762** in an array names azResult. Then azResult holds this content: 1763** 1764** <blockquote><pre> 1765** azResult[0] = "Name"; 1766** azResult[1] = "Age"; 1767** azResult[2] = "Alice"; 1768** azResult[3] = "43"; 1769** azResult[4] = "Bob"; 1770** azResult[5] = "28"; 1771** azResult[6] = "Cindy"; 1772** azResult[7] = "21"; 1773** </pre></blockquote> 1774** 1775** ^The sqlite3_get_table() function evaluates one or more 1776** semicolon-separated SQL statements in the zero-terminated UTF-8 1777** string of its 2nd parameter and returns a result table to the 1778** pointer given in its 3rd parameter. 1779** 1780** After the application has finished with the result from sqlite3_get_table(), 1781** it should pass the result table pointer to sqlite3_free_table() in order to 1782** release the memory that was malloced. Because of the way the 1783** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 1784** function must not try to call [sqlite3_free()] directly. Only 1785** [sqlite3_free_table()] is able to release the memory properly and safely. 1786** 1787** ^(The sqlite3_get_table() interface is implemented as a wrapper around 1788** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 1789** to any internal data structures of SQLite. It uses only the public 1790** interface defined here. As a consequence, errors that occur in the 1791** wrapper layer outside of the internal [sqlite3_exec()] call are not 1792** reflected in subsequent calls to [sqlite3_errcode()] or 1793** [sqlite3_errmsg()].)^ 1794*/ 1795SQLITE_API int sqlite3_get_table( 1796 sqlite3 *db, /* An open database */ 1797 const char *zSql, /* SQL to be evaluated */ 1798 char ***pazResult, /* Results of the query */ 1799 int *pnRow, /* Number of result rows written here */ 1800 int *pnColumn, /* Number of result columns written here */ 1801 char **pzErrmsg /* Error msg written here */ 1802); 1803SQLITE_API void sqlite3_free_table(char **result); 1804 1805/* 1806** CAPI3REF: Formatted String Printing Functions 1807** 1808** These routines are work-alikes of the "printf()" family of functions 1809** from the standard C library. 1810** 1811** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 1812** results into memory obtained from [sqlite3_malloc()]. 1813** The strings returned by these two routines should be 1814** released by [sqlite3_free()]. ^Both routines return a 1815** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 1816** memory to hold the resulting string. 1817** 1818** ^(In sqlite3_snprintf() routine is similar to "snprintf()" from 1819** the standard C library. The result is written into the 1820** buffer supplied as the second parameter whose size is given by 1821** the first parameter. Note that the order of the 1822** first two parameters is reversed from snprintf().)^ This is an 1823** historical accident that cannot be fixed without breaking 1824** backwards compatibility. ^(Note also that sqlite3_snprintf() 1825** returns a pointer to its buffer instead of the number of 1826** characters actually written into the buffer.)^ We admit that 1827** the number of characters written would be a more useful return 1828** value but we cannot change the implementation of sqlite3_snprintf() 1829** now without breaking compatibility. 1830** 1831** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 1832** guarantees that the buffer is always zero-terminated. ^The first 1833** parameter "n" is the total size of the buffer, including space for 1834** the zero terminator. So the longest string that can be completely 1835** written will be n-1 characters. 1836** 1837** These routines all implement some additional formatting 1838** options that are useful for constructing SQL statements. 1839** All of the usual printf() formatting options apply. In addition, there 1840** is are "%q", "%Q", and "%z" options. 1841** 1842** ^(The %q option works like %s in that it substitutes a null-terminated 1843** string from the argument list. But %q also doubles every '\'' character. 1844** %q is designed for use inside a string literal.)^ By doubling each '\'' 1845** character it escapes that character and allows it to be inserted into 1846** the string. 1847** 1848** For example, assume the string variable zText contains text as follows: 1849** 1850** <blockquote><pre> 1851** char *zText = "It's a happy day!"; 1852** </pre></blockquote> 1853** 1854** One can use this text in an SQL statement as follows: 1855** 1856** <blockquote><pre> 1857** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 1858** sqlite3_exec(db, zSQL, 0, 0, 0); 1859** sqlite3_free(zSQL); 1860** </pre></blockquote> 1861** 1862** Because the %q format string is used, the '\'' character in zText 1863** is escaped and the SQL generated is as follows: 1864** 1865** <blockquote><pre> 1866** INSERT INTO table1 VALUES('It''s a happy day!') 1867** </pre></blockquote> 1868** 1869** This is correct. Had we used %s instead of %q, the generated SQL 1870** would have looked like this: 1871** 1872** <blockquote><pre> 1873** INSERT INTO table1 VALUES('It's a happy day!'); 1874** </pre></blockquote> 1875** 1876** This second example is an SQL syntax error. As a general rule you should 1877** always use %q instead of %s when inserting text into a string literal. 1878** 1879** ^(The %Q option works like %q except it also adds single quotes around 1880** the outside of the total string. Additionally, if the parameter in the 1881** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 1882** single quotes).)^ So, for example, one could say: 1883** 1884** <blockquote><pre> 1885** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 1886** sqlite3_exec(db, zSQL, 0, 0, 0); 1887** sqlite3_free(zSQL); 1888** </pre></blockquote> 1889** 1890** The code above will render a correct SQL statement in the zSQL 1891** variable even if the zText variable is a NULL pointer. 1892** 1893** ^(The "%z" formatting option works like "%s" but with the 1894** addition that after the string has been read and copied into 1895** the result, [sqlite3_free()] is called on the input string.)^ 1896*/ 1897SQLITE_API char *sqlite3_mprintf(const char*,...); 1898SQLITE_API char *sqlite3_vmprintf(const char*, va_list); 1899SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...); 1900 1901/* 1902** CAPI3REF: Memory Allocation Subsystem 1903** 1904** The SQLite core uses these three routines for all of its own 1905** internal memory allocation needs. "Core" in the previous sentence 1906** does not include operating-system specific VFS implementation. The 1907** Windows VFS uses native malloc() and free() for some operations. 1908** 1909** ^The sqlite3_malloc() routine returns a pointer to a block 1910** of memory at least N bytes in length, where N is the parameter. 1911** ^If sqlite3_malloc() is unable to obtain sufficient free 1912** memory, it returns a NULL pointer. ^If the parameter N to 1913** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 1914** a NULL pointer. 1915** 1916** ^Calling sqlite3_free() with a pointer previously returned 1917** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 1918** that it might be reused. ^The sqlite3_free() routine is 1919** a no-op if is called with a NULL pointer. Passing a NULL pointer 1920** to sqlite3_free() is harmless. After being freed, memory 1921** should neither be read nor written. Even reading previously freed 1922** memory might result in a segmentation fault or other severe error. 1923** Memory corruption, a segmentation fault, or other severe error 1924** might result if sqlite3_free() is called with a non-NULL pointer that 1925** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 1926** 1927** ^(The sqlite3_realloc() interface attempts to resize a 1928** prior memory allocation to be at least N bytes, where N is the 1929** second parameter. The memory allocation to be resized is the first 1930** parameter.)^ ^ If the first parameter to sqlite3_realloc() 1931** is a NULL pointer then its behavior is identical to calling 1932** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc(). 1933** ^If the second parameter to sqlite3_realloc() is zero or 1934** negative then the behavior is exactly the same as calling 1935** sqlite3_free(P) where P is the first parameter to sqlite3_realloc(). 1936** ^sqlite3_realloc() returns a pointer to a memory allocation 1937** of at least N bytes in size or NULL if sufficient memory is unavailable. 1938** ^If M is the size of the prior allocation, then min(N,M) bytes 1939** of the prior allocation are copied into the beginning of buffer returned 1940** by sqlite3_realloc() and the prior allocation is freed. 1941** ^If sqlite3_realloc() returns NULL, then the prior allocation 1942** is not freed. 1943** 1944** ^The memory returned by sqlite3_malloc() and sqlite3_realloc() 1945** is always aligned to at least an 8 byte boundary. 1946** 1947** In SQLite version 3.5.0 and 3.5.1, it was possible to define 1948** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 1949** implementation of these routines to be omitted. That capability 1950** is no longer provided. Only built-in memory allocators can be used. 1951** 1952** The Windows OS interface layer calls 1953** the system malloc() and free() directly when converting 1954** filenames between the UTF-8 encoding used by SQLite 1955** and whatever filename encoding is used by the particular Windows 1956** installation. Memory allocation errors are detected, but 1957** they are reported back as [SQLITE_CANTOPEN] or 1958** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 1959** 1960** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 1961** must be either NULL or else pointers obtained from a prior 1962** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 1963** not yet been released. 1964** 1965** The application must not read or write any part of 1966** a block of memory after it has been released using 1967** [sqlite3_free()] or [sqlite3_realloc()]. 1968*/ 1969SQLITE_API void *sqlite3_malloc(int); 1970SQLITE_API void *sqlite3_realloc(void*, int); 1971SQLITE_API void sqlite3_free(void*); 1972 1973/* 1974** CAPI3REF: Memory Allocator Statistics 1975** 1976** SQLite provides these two interfaces for reporting on the status 1977** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 1978** routines, which form the built-in memory allocation subsystem. 1979** 1980** ^The [sqlite3_memory_used()] routine returns the number of bytes 1981** of memory currently outstanding (malloced but not freed). 1982** ^The [sqlite3_memory_highwater()] routine returns the maximum 1983** value of [sqlite3_memory_used()] since the high-water mark 1984** was last reset. ^The values returned by [sqlite3_memory_used()] and 1985** [sqlite3_memory_highwater()] include any overhead 1986** added by SQLite in its implementation of [sqlite3_malloc()], 1987** but not overhead added by the any underlying system library 1988** routines that [sqlite3_malloc()] may call. 1989** 1990** ^The memory high-water mark is reset to the current value of 1991** [sqlite3_memory_used()] if and only if the parameter to 1992** [sqlite3_memory_highwater()] is true. ^The value returned 1993** by [sqlite3_memory_highwater(1)] is the high-water mark 1994** prior to the reset. 1995*/ 1996SQLITE_API sqlite3_int64 sqlite3_memory_used(void); 1997SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 1998 1999/* 2000** CAPI3REF: Pseudo-Random Number Generator 2001** 2002** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2003** select random [ROWID | ROWIDs] when inserting new records into a table that 2004** already uses the largest possible [ROWID]. The PRNG is also used for 2005** the build-in random() and randomblob() SQL functions. This interface allows 2006** applications to access the same PRNG for other purposes. 2007** 2008** ^A call to this routine stores N bytes of randomness into buffer P. 2009** 2010** ^The first time this routine is invoked (either internally or by 2011** the application) the PRNG is seeded using randomness obtained 2012** from the xRandomness method of the default [sqlite3_vfs] object. 2013** ^On all subsequent invocations, the pseudo-randomness is generated 2014** internally and without recourse to the [sqlite3_vfs] xRandomness 2015** method. 2016*/ 2017SQLITE_API void sqlite3_randomness(int N, void *P); 2018 2019/* 2020** CAPI3REF: Compile-Time Authorization Callbacks 2021** 2022** ^This routine registers a authorizer callback with a particular 2023** [database connection], supplied in the first argument. 2024** ^The authorizer callback is invoked as SQL statements are being compiled 2025** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2026** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various 2027** points during the compilation process, as logic is being created 2028** to perform various actions, the authorizer callback is invoked to 2029** see if those actions are allowed. ^The authorizer callback should 2030** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2031** specific action but allow the SQL statement to continue to be 2032** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2033** rejected with an error. ^If the authorizer callback returns 2034** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2035** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2036** the authorizer will fail with an error message. 2037** 2038** When the callback returns [SQLITE_OK], that means the operation 2039** requested is ok. ^When the callback returns [SQLITE_DENY], the 2040** [sqlite3_prepare_v2()] or equivalent call that triggered the 2041** authorizer will fail with an error message explaining that 2042** access is denied. 2043** 2044** ^The first parameter to the authorizer callback is a copy of the third 2045** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2046** to the callback is an integer [SQLITE_COPY | action code] that specifies 2047** the particular action to be authorized. ^The third through sixth parameters 2048** to the callback are zero-terminated strings that contain additional 2049** details about the action to be authorized. 2050** 2051** ^If the action code is [SQLITE_READ] 2052** and the callback returns [SQLITE_IGNORE] then the 2053** [prepared statement] statement is constructed to substitute 2054** a NULL value in place of the table column that would have 2055** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2056** return can be used to deny an untrusted user access to individual 2057** columns of a table. 2058** ^If the action code is [SQLITE_DELETE] and the callback returns 2059** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2060** [truncate optimization] is disabled and all rows are deleted individually. 2061** 2062** An authorizer is used when [sqlite3_prepare | preparing] 2063** SQL statements from an untrusted source, to ensure that the SQL statements 2064** do not try to access data they are not allowed to see, or that they do not 2065** try to execute malicious statements that damage the database. For 2066** example, an application may allow a user to enter arbitrary 2067** SQL queries for evaluation by a database. But the application does 2068** not want the user to be able to make arbitrary changes to the 2069** database. An authorizer could then be put in place while the 2070** user-entered SQL is being [sqlite3_prepare | prepared] that 2071** disallows everything except [SELECT] statements. 2072** 2073** Applications that need to process SQL from untrusted sources 2074** might also consider lowering resource limits using [sqlite3_limit()] 2075** and limiting database size using the [max_page_count] [PRAGMA] 2076** in addition to using an authorizer. 2077** 2078** ^(Only a single authorizer can be in place on a database connection 2079** at a time. Each call to sqlite3_set_authorizer overrides the 2080** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2081** The authorizer is disabled by default. 2082** 2083** The authorizer callback must not do anything that will modify 2084** the database connection that invoked the authorizer callback. 2085** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2086** database connections for the meaning of "modify" in this paragraph. 2087** 2088** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2089** statement might be re-prepared during [sqlite3_step()] due to a 2090** schema change. Hence, the application should ensure that the 2091** correct authorizer callback remains in place during the [sqlite3_step()]. 2092** 2093** ^Note that the authorizer callback is invoked only during 2094** [sqlite3_prepare()] or its variants. Authorization is not 2095** performed during statement evaluation in [sqlite3_step()], unless 2096** as stated in the previous paragraph, sqlite3_step() invokes 2097** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2098*/ 2099SQLITE_API int sqlite3_set_authorizer( 2100 sqlite3*, 2101 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2102 void *pUserData 2103); 2104 2105/* 2106** CAPI3REF: Authorizer Return Codes 2107** 2108** The [sqlite3_set_authorizer | authorizer callback function] must 2109** return either [SQLITE_OK] or one of these two constants in order 2110** to signal SQLite whether or not the action is permitted. See the 2111** [sqlite3_set_authorizer | authorizer documentation] for additional 2112** information. 2113*/ 2114#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2115#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2116 2117/* 2118** CAPI3REF: Authorizer Action Codes 2119** 2120** The [sqlite3_set_authorizer()] interface registers a callback function 2121** that is invoked to authorize certain SQL statement actions. The 2122** second parameter to the callback is an integer code that specifies 2123** what action is being authorized. These are the integer action codes that 2124** the authorizer callback may be passed. 2125** 2126** These action code values signify what kind of operation is to be 2127** authorized. The 3rd and 4th parameters to the authorization 2128** callback function will be parameters or NULL depending on which of these 2129** codes is used as the second parameter. ^(The 5th parameter to the 2130** authorizer callback is the name of the database ("main", "temp", 2131** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2132** is the name of the inner-most trigger or view that is responsible for 2133** the access attempt or NULL if this access attempt is directly from 2134** top-level SQL code. 2135*/ 2136/******************************************* 3rd ************ 4th ***********/ 2137#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2138#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2139#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2140#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2141#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2142#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2143#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2144#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2145#define SQLITE_DELETE 9 /* Table Name NULL */ 2146#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2147#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2148#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2149#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2150#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2151#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2152#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2153#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2154#define SQLITE_INSERT 18 /* Table Name NULL */ 2155#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2156#define SQLITE_READ 20 /* Table Name Column Name */ 2157#define SQLITE_SELECT 21 /* NULL NULL */ 2158#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2159#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2160#define SQLITE_ATTACH 24 /* Filename NULL */ 2161#define SQLITE_DETACH 25 /* Database Name NULL */ 2162#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2163#define SQLITE_REINDEX 27 /* Index Name NULL */ 2164#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2165#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2166#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2167#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2168#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2169#define SQLITE_COPY 0 /* No longer used */ 2170 2171/* 2172** CAPI3REF: Tracing And Profiling Functions 2173** 2174** These routines register callback functions that can be used for 2175** tracing and profiling the execution of SQL statements. 2176** 2177** ^The callback function registered by sqlite3_trace() is invoked at 2178** various times when an SQL statement is being run by [sqlite3_step()]. 2179** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2180** SQL statement text as the statement first begins executing. 2181** ^(Additional sqlite3_trace() callbacks might occur 2182** as each triggered subprogram is entered. The callbacks for triggers 2183** contain a UTF-8 SQL comment that identifies the trigger.)^ 2184** 2185** ^The callback function registered by sqlite3_profile() is invoked 2186** as each SQL statement finishes. ^The profile callback contains 2187** the original statement text and an estimate of wall-clock time 2188** of how long that statement took to run. ^The profile callback 2189** time is in units of nanoseconds, however the current implementation 2190** is only capable of millisecond resolution so the six least significant 2191** digits in the time are meaningless. Future versions of SQLite 2192** might provide greater resolution on the profiler callback. The 2193** sqlite3_profile() function is considered experimental and is 2194** subject to change in future versions of SQLite. 2195*/ 2196SQLITE_API void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*); 2197SQLITE_API SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*, 2198 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2199 2200/* 2201** CAPI3REF: Query Progress Callbacks 2202** 2203** ^This routine configures a callback function - the 2204** progress callback - that is invoked periodically during long 2205** running calls to [sqlite3_exec()], [sqlite3_step()] and 2206** [sqlite3_get_table()]. An example use for this 2207** interface is to keep a GUI updated during a large query. 2208** 2209** ^If the progress callback returns non-zero, the operation is 2210** interrupted. This feature can be used to implement a 2211** "Cancel" button on a GUI progress dialog box. 2212** 2213** The progress handler must not do anything that will modify 2214** the database connection that invoked the progress handler. 2215** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2216** database connections for the meaning of "modify" in this paragraph. 2217** 2218*/ 2219SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 2220 2221/* 2222** CAPI3REF: Opening A New Database Connection 2223** 2224** ^These routines open an SQLite database file whose name is given by the 2225** filename argument. ^The filename argument is interpreted as UTF-8 for 2226** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 2227** order for sqlite3_open16(). ^(A [database connection] handle is usually 2228** returned in *ppDb, even if an error occurs. The only exception is that 2229** if SQLite is unable to allocate memory to hold the [sqlite3] object, 2230** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 2231** object.)^ ^(If the database is opened (and/or created) successfully, then 2232** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 2233** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 2234** an English language description of the error following a failure of any 2235** of the sqlite3_open() routines. 2236** 2237** ^The default encoding for the database will be UTF-8 if 2238** sqlite3_open() or sqlite3_open_v2() is called and 2239** UTF-16 in the native byte order if sqlite3_open16() is used. 2240** 2241** Whether or not an error occurs when it is opened, resources 2242** associated with the [database connection] handle should be released by 2243** passing it to [sqlite3_close()] when it is no longer required. 2244** 2245** The sqlite3_open_v2() interface works like sqlite3_open() 2246** except that it accepts two additional parameters for additional control 2247** over the new database connection. ^(The flags parameter to 2248** sqlite3_open_v2() can take one of 2249** the following three values, optionally combined with the 2250** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 2251** and/or [SQLITE_OPEN_PRIVATECACHE] flags:)^ 2252** 2253** <dl> 2254** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 2255** <dd>The database is opened in read-only mode. If the database does not 2256** already exist, an error is returned.</dd>)^ 2257** 2258** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 2259** <dd>The database is opened for reading and writing if possible, or reading 2260** only if the file is write protected by the operating system. In either 2261** case the database must already exist, otherwise an error is returned.</dd>)^ 2262** 2263** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 2264** <dd>The database is opened for reading and writing, and is creates it if 2265** it does not already exist. This is the behavior that is always used for 2266** sqlite3_open() and sqlite3_open16().</dd>)^ 2267** </dl> 2268** 2269** If the 3rd parameter to sqlite3_open_v2() is not one of the 2270** combinations shown above or one of the combinations shown above combined 2271** with the [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], 2272** [SQLITE_OPEN_SHAREDCACHE] and/or [SQLITE_OPEN_SHAREDCACHE] flags, 2273** then the behavior is undefined. 2274** 2275** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 2276** opens in the multi-thread [threading mode] as long as the single-thread 2277** mode has not been set at compile-time or start-time. ^If the 2278** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 2279** in the serialized [threading mode] unless single-thread was 2280** previously selected at compile-time or start-time. 2281** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 2282** eligible to use [shared cache mode], regardless of whether or not shared 2283** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 2284** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 2285** participate in [shared cache mode] even if it is enabled. 2286** 2287** ^If the filename is ":memory:", then a private, temporary in-memory database 2288** is created for the connection. ^This in-memory database will vanish when 2289** the database connection is closed. Future versions of SQLite might 2290** make use of additional special filenames that begin with the ":" character. 2291** It is recommended that when a database filename actually does begin with 2292** a ":" character you should prefix the filename with a pathname such as 2293** "./" to avoid ambiguity. 2294** 2295** ^If the filename is an empty string, then a private, temporary 2296** on-disk database will be created. ^This private database will be 2297** automatically deleted as soon as the database connection is closed. 2298** 2299** ^The fourth parameter to sqlite3_open_v2() is the name of the 2300** [sqlite3_vfs] object that defines the operating system interface that 2301** the new database connection should use. ^If the fourth parameter is 2302** a NULL pointer then the default [sqlite3_vfs] object is used. 2303** 2304** <b>Note to Windows users:</b> The encoding used for the filename argument 2305** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 2306** codepage is currently defined. Filenames containing international 2307** characters must be converted to UTF-8 prior to passing them into 2308** sqlite3_open() or sqlite3_open_v2(). 2309*/ 2310SQLITE_API int sqlite3_open( 2311 const char *filename, /* Database filename (UTF-8) */ 2312 sqlite3 **ppDb /* OUT: SQLite db handle */ 2313); 2314SQLITE_API int sqlite3_open16( 2315 const void *filename, /* Database filename (UTF-16) */ 2316 sqlite3 **ppDb /* OUT: SQLite db handle */ 2317); 2318SQLITE_API int sqlite3_open_v2( 2319 const char *filename, /* Database filename (UTF-8) */ 2320 sqlite3 **ppDb, /* OUT: SQLite db handle */ 2321 int flags, /* Flags */ 2322 const char *zVfs /* Name of VFS module to use */ 2323); 2324 2325/* 2326** CAPI3REF: Error Codes And Messages 2327** 2328** ^The sqlite3_errcode() interface returns the numeric [result code] or 2329** [extended result code] for the most recent failed sqlite3_* API call 2330** associated with a [database connection]. If a prior API call failed 2331** but the most recent API call succeeded, the return value from 2332** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode() 2333** interface is the same except that it always returns the 2334** [extended result code] even when extended result codes are 2335** disabled. 2336** 2337** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 2338** text that describes the error, as either UTF-8 or UTF-16 respectively. 2339** ^(Memory to hold the error message string is managed internally. 2340** The application does not need to worry about freeing the result. 2341** However, the error string might be overwritten or deallocated by 2342** subsequent calls to other SQLite interface functions.)^ 2343** 2344** When the serialized [threading mode] is in use, it might be the 2345** case that a second error occurs on a separate thread in between 2346** the time of the first error and the call to these interfaces. 2347** When that happens, the second error will be reported since these 2348** interfaces always report the most recent result. To avoid 2349** this, each thread can obtain exclusive use of the [database connection] D 2350** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 2351** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 2352** all calls to the interfaces listed here are completed. 2353** 2354** If an interface fails with SQLITE_MISUSE, that means the interface 2355** was invoked incorrectly by the application. In that case, the 2356** error code and message may or may not be set. 2357*/ 2358SQLITE_API int sqlite3_errcode(sqlite3 *db); 2359SQLITE_API int sqlite3_extended_errcode(sqlite3 *db); 2360SQLITE_API const char *sqlite3_errmsg(sqlite3*); 2361SQLITE_API const void *sqlite3_errmsg16(sqlite3*); 2362 2363/* 2364** CAPI3REF: SQL Statement Object 2365** KEYWORDS: {prepared statement} {prepared statements} 2366** 2367** An instance of this object represents a single SQL statement. 2368** This object is variously known as a "prepared statement" or a 2369** "compiled SQL statement" or simply as a "statement". 2370** 2371** The life of a statement object goes something like this: 2372** 2373** <ol> 2374** <li> Create the object using [sqlite3_prepare_v2()] or a related 2375** function. 2376** <li> Bind values to [host parameters] using the sqlite3_bind_*() 2377** interfaces. 2378** <li> Run the SQL by calling [sqlite3_step()] one or more times. 2379** <li> Reset the statement using [sqlite3_reset()] then go back 2380** to step 2. Do this zero or more times. 2381** <li> Destroy the object using [sqlite3_finalize()]. 2382** </ol> 2383** 2384** Refer to documentation on individual methods above for additional 2385** information. 2386*/ 2387typedef struct sqlite3_stmt sqlite3_stmt; 2388 2389/* 2390** CAPI3REF: Run-time Limits 2391** 2392** ^(This interface allows the size of various constructs to be limited 2393** on a connection by connection basis. The first parameter is the 2394** [database connection] whose limit is to be set or queried. The 2395** second parameter is one of the [limit categories] that define a 2396** class of constructs to be size limited. The third parameter is the 2397** new limit for that construct. The function returns the old limit.)^ 2398** 2399** ^If the new limit is a negative number, the limit is unchanged. 2400** ^(For the limit category of SQLITE_LIMIT_XYZ there is a 2401** [limits | hard upper bound] 2402** set by a compile-time C preprocessor macro named 2403** [limits | SQLITE_MAX_XYZ]. 2404** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 2405** ^Attempts to increase a limit above its hard upper bound are 2406** silently truncated to the hard upper bound. 2407** 2408** Run-time limits are intended for use in applications that manage 2409** both their own internal database and also databases that are controlled 2410** by untrusted external sources. An example application might be a 2411** web browser that has its own databases for storing history and 2412** separate databases controlled by JavaScript applications downloaded 2413** off the Internet. The internal databases can be given the 2414** large, default limits. Databases managed by external sources can 2415** be given much smaller limits designed to prevent a denial of service 2416** attack. Developers might also want to use the [sqlite3_set_authorizer()] 2417** interface to further control untrusted SQL. The size of the database 2418** created by an untrusted script can be contained using the 2419** [max_page_count] [PRAGMA]. 2420** 2421** New run-time limit categories may be added in future releases. 2422*/ 2423SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal); 2424 2425/* 2426** CAPI3REF: Run-Time Limit Categories 2427** KEYWORDS: {limit category} {*limit categories} 2428** 2429** These constants define various performance limits 2430** that can be lowered at run-time using [sqlite3_limit()]. 2431** The synopsis of the meanings of the various limits is shown below. 2432** Additional information is available at [limits | Limits in SQLite]. 2433** 2434** <dl> 2435** ^(<dt>SQLITE_LIMIT_LENGTH</dt> 2436** <dd>The maximum size of any string or BLOB or table row.<dd>)^ 2437** 2438** ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 2439** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 2440** 2441** ^(<dt>SQLITE_LIMIT_COLUMN</dt> 2442** <dd>The maximum number of columns in a table definition or in the 2443** result set of a [SELECT] or the maximum number of columns in an index 2444** or in an ORDER BY or GROUP BY clause.</dd>)^ 2445** 2446** ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 2447** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 2448** 2449** ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 2450** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 2451** 2452** ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 2453** <dd>The maximum number of instructions in a virtual machine program 2454** used to implement an SQL statement.</dd>)^ 2455** 2456** ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 2457** <dd>The maximum number of arguments on a function.</dd>)^ 2458** 2459** ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 2460** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 2461** 2462** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 2463** <dd>The maximum length of the pattern argument to the [LIKE] or 2464** [GLOB] operators.</dd>)^ 2465** 2466** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 2467** <dd>The maximum number of variables in an SQL statement that can 2468** be bound.</dd>)^ 2469** 2470** ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 2471** <dd>The maximum depth of recursion for triggers.</dd>)^ 2472** </dl> 2473*/ 2474#define SQLITE_LIMIT_LENGTH 0 2475#define SQLITE_LIMIT_SQL_LENGTH 1 2476#define SQLITE_LIMIT_COLUMN 2 2477#define SQLITE_LIMIT_EXPR_DEPTH 3 2478#define SQLITE_LIMIT_COMPOUND_SELECT 4 2479#define SQLITE_LIMIT_VDBE_OP 5 2480#define SQLITE_LIMIT_FUNCTION_ARG 6 2481#define SQLITE_LIMIT_ATTACHED 7 2482#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 2483#define SQLITE_LIMIT_VARIABLE_NUMBER 9 2484#define SQLITE_LIMIT_TRIGGER_DEPTH 10 2485 2486/* 2487** CAPI3REF: Compiling An SQL Statement 2488** KEYWORDS: {SQL statement compiler} 2489** 2490** To execute an SQL query, it must first be compiled into a byte-code 2491** program using one of these routines. 2492** 2493** The first argument, "db", is a [database connection] obtained from a 2494** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 2495** [sqlite3_open16()]. The database connection must not have been closed. 2496** 2497** The second argument, "zSql", is the statement to be compiled, encoded 2498** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() 2499** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() 2500** use UTF-16. 2501** 2502** ^If the nByte argument is less than zero, then zSql is read up to the 2503** first zero terminator. ^If nByte is non-negative, then it is the maximum 2504** number of bytes read from zSql. ^When nByte is non-negative, the 2505** zSql string ends at either the first '\000' or '\u0000' character or 2506** the nByte-th byte, whichever comes first. If the caller knows 2507** that the supplied string is nul-terminated, then there is a small 2508** performance advantage to be gained by passing an nByte parameter that 2509** is equal to the number of bytes in the input string <i>including</i> 2510** the nul-terminator bytes. 2511** 2512** ^If pzTail is not NULL then *pzTail is made to point to the first byte 2513** past the end of the first SQL statement in zSql. These routines only 2514** compile the first statement in zSql, so *pzTail is left pointing to 2515** what remains uncompiled. 2516** 2517** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 2518** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 2519** to NULL. ^If the input text contains no SQL (if the input is an empty 2520** string or a comment) then *ppStmt is set to NULL. 2521** The calling procedure is responsible for deleting the compiled 2522** SQL statement using [sqlite3_finalize()] after it has finished with it. 2523** ppStmt may not be NULL. 2524** 2525** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 2526** otherwise an [error code] is returned. 2527** 2528** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are 2529** recommended for all new programs. The two older interfaces are retained 2530** for backwards compatibility, but their use is discouraged. 2531** ^In the "v2" interfaces, the prepared statement 2532** that is returned (the [sqlite3_stmt] object) contains a copy of the 2533** original SQL text. This causes the [sqlite3_step()] interface to 2534** behave differently in three ways: 2535** 2536** <ol> 2537** <li> 2538** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 2539** always used to do, [sqlite3_step()] will automatically recompile the SQL 2540** statement and try to run it again. ^If the schema has changed in 2541** a way that makes the statement no longer valid, [sqlite3_step()] will still 2542** return [SQLITE_SCHEMA]. But unlike the legacy behavior, [SQLITE_SCHEMA] is 2543** now a fatal error. Calling [sqlite3_prepare_v2()] again will not make the 2544** error go away. Note: use [sqlite3_errmsg()] to find the text 2545** of the parsing error that results in an [SQLITE_SCHEMA] return. 2546** </li> 2547** 2548** <li> 2549** ^When an error occurs, [sqlite3_step()] will return one of the detailed 2550** [error codes] or [extended error codes]. ^The legacy behavior was that 2551** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 2552** and the application would have to make a second call to [sqlite3_reset()] 2553** in order to find the underlying cause of the problem. With the "v2" prepare 2554** interfaces, the underlying reason for the error is returned immediately. 2555** </li> 2556** 2557** <li> 2558** ^If the value of a [parameter | host parameter] in the WHERE clause might 2559** change the query plan for a statement, then the statement may be 2560** automatically recompiled (as if there had been a schema change) on the first 2561** [sqlite3_step()] call following any change to the 2562** [sqlite3_bind_text | bindings] of the [parameter]. 2563** </li> 2564** </ol> 2565*/ 2566SQLITE_API int sqlite3_prepare( 2567 sqlite3 *db, /* Database handle */ 2568 const char *zSql, /* SQL statement, UTF-8 encoded */ 2569 int nByte, /* Maximum length of zSql in bytes. */ 2570 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2571 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2572); 2573SQLITE_API int sqlite3_prepare_v2( 2574 sqlite3 *db, /* Database handle */ 2575 const char *zSql, /* SQL statement, UTF-8 encoded */ 2576 int nByte, /* Maximum length of zSql in bytes. */ 2577 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2578 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2579); 2580SQLITE_API int sqlite3_prepare16( 2581 sqlite3 *db, /* Database handle */ 2582 const void *zSql, /* SQL statement, UTF-16 encoded */ 2583 int nByte, /* Maximum length of zSql in bytes. */ 2584 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2585 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2586); 2587SQLITE_API int sqlite3_prepare16_v2( 2588 sqlite3 *db, /* Database handle */ 2589 const void *zSql, /* SQL statement, UTF-16 encoded */ 2590 int nByte, /* Maximum length of zSql in bytes. */ 2591 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2592 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2593); 2594 2595/* 2596** CAPI3REF: Retrieving Statement SQL 2597** 2598** ^This interface can be used to retrieve a saved copy of the original 2599** SQL text used to create a [prepared statement] if that statement was 2600** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. 2601*/ 2602SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt); 2603 2604/* 2605** CAPI3REF: Dynamically Typed Value Object 2606** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 2607** 2608** SQLite uses the sqlite3_value object to represent all values 2609** that can be stored in a database table. SQLite uses dynamic typing 2610** for the values it stores. ^Values stored in sqlite3_value objects 2611** can be integers, floating point values, strings, BLOBs, or NULL. 2612** 2613** An sqlite3_value object may be either "protected" or "unprotected". 2614** Some interfaces require a protected sqlite3_value. Other interfaces 2615** will accept either a protected or an unprotected sqlite3_value. 2616** Every interface that accepts sqlite3_value arguments specifies 2617** whether or not it requires a protected sqlite3_value. 2618** 2619** The terms "protected" and "unprotected" refer to whether or not 2620** a mutex is held. A internal mutex is held for a protected 2621** sqlite3_value object but no mutex is held for an unprotected 2622** sqlite3_value object. If SQLite is compiled to be single-threaded 2623** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 2624** or if SQLite is run in one of reduced mutex modes 2625** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 2626** then there is no distinction between protected and unprotected 2627** sqlite3_value objects and they can be used interchangeably. However, 2628** for maximum code portability it is recommended that applications 2629** still make the distinction between between protected and unprotected 2630** sqlite3_value objects even when not strictly required. 2631** 2632** ^The sqlite3_value objects that are passed as parameters into the 2633** implementation of [application-defined SQL functions] are protected. 2634** ^The sqlite3_value object returned by 2635** [sqlite3_column_value()] is unprotected. 2636** Unprotected sqlite3_value objects may only be used with 2637** [sqlite3_result_value()] and [sqlite3_bind_value()]. 2638** The [sqlite3_value_blob | sqlite3_value_type()] family of 2639** interfaces require protected sqlite3_value objects. 2640*/ 2641typedef struct Mem sqlite3_value; 2642 2643/* 2644** CAPI3REF: SQL Function Context Object 2645** 2646** The context in which an SQL function executes is stored in an 2647** sqlite3_context object. ^A pointer to an sqlite3_context object 2648** is always first parameter to [application-defined SQL functions]. 2649** The application-defined SQL function implementation will pass this 2650** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 2651** [sqlite3_aggregate_context()], [sqlite3_user_data()], 2652** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 2653** and/or [sqlite3_set_auxdata()]. 2654*/ 2655typedef struct sqlite3_context sqlite3_context; 2656 2657/* 2658** CAPI3REF: Binding Values To Prepared Statements 2659** KEYWORDS: {host parameter} {host parameters} {host parameter name} 2660** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 2661** 2662** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 2663** literals may be replaced by a [parameter] that matches one of following 2664** templates: 2665** 2666** <ul> 2667** <li> ? 2668** <li> ?NNN 2669** <li> :VVV 2670** <li> @VVV 2671** <li> $VVV 2672** </ul> 2673** 2674** In the templates above, NNN represents an integer literal, 2675** and VVV represents an alphanumeric identifier.)^ ^The values of these 2676** parameters (also called "host parameter names" or "SQL parameters") 2677** can be set using the sqlite3_bind_*() routines defined here. 2678** 2679** ^The first argument to the sqlite3_bind_*() routines is always 2680** a pointer to the [sqlite3_stmt] object returned from 2681** [sqlite3_prepare_v2()] or its variants. 2682** 2683** ^The second argument is the index of the SQL parameter to be set. 2684** ^The leftmost SQL parameter has an index of 1. ^When the same named 2685** SQL parameter is used more than once, second and subsequent 2686** occurrences have the same index as the first occurrence. 2687** ^The index for named parameters can be looked up using the 2688** [sqlite3_bind_parameter_index()] API if desired. ^The index 2689** for "?NNN" parameters is the value of NNN. 2690** ^The NNN value must be between 1 and the [sqlite3_limit()] 2691** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 2692** 2693** ^The third argument is the value to bind to the parameter. 2694** 2695** ^(In those routines that have a fourth argument, its value is the 2696** number of bytes in the parameter. To be clear: the value is the 2697** number of <u>bytes</u> in the value, not the number of characters.)^ 2698** ^If the fourth parameter is negative, the length of the string is 2699** the number of bytes up to the first zero terminator. 2700** 2701** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and 2702** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or 2703** string after SQLite has finished with it. ^If the fifth argument is 2704** the special value [SQLITE_STATIC], then SQLite assumes that the 2705** information is in static, unmanaged space and does not need to be freed. 2706** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 2707** SQLite makes its own private copy of the data immediately, before 2708** the sqlite3_bind_*() routine returns. 2709** 2710** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 2711** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 2712** (just an integer to hold its size) while it is being processed. 2713** Zeroblobs are intended to serve as placeholders for BLOBs whose 2714** content is later written using 2715** [sqlite3_blob_open | incremental BLOB I/O] routines. 2716** ^A negative value for the zeroblob results in a zero-length BLOB. 2717** 2718** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 2719** for the [prepared statement] or with a prepared statement for which 2720** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 2721** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 2722** routine is passed a [prepared statement] that has been finalized, the 2723** result is undefined and probably harmful. 2724** 2725** ^Bindings are not cleared by the [sqlite3_reset()] routine. 2726** ^Unbound parameters are interpreted as NULL. 2727** 2728** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 2729** [error code] if anything goes wrong. 2730** ^[SQLITE_RANGE] is returned if the parameter 2731** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 2732** 2733** See also: [sqlite3_bind_parameter_count()], 2734** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 2735*/ 2736SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 2737SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double); 2738SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int); 2739SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 2740SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int); 2741SQLITE_API int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*)); 2742SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 2743SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 2744SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 2745 2746/* 2747** CAPI3REF: Number Of SQL Parameters 2748** 2749** ^This routine can be used to find the number of [SQL parameters] 2750** in a [prepared statement]. SQL parameters are tokens of the 2751** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 2752** placeholders for values that are [sqlite3_bind_blob | bound] 2753** to the parameters at a later time. 2754** 2755** ^(This routine actually returns the index of the largest (rightmost) 2756** parameter. For all forms except ?NNN, this will correspond to the 2757** number of unique parameters. If parameters of the ?NNN form are used, 2758** there may be gaps in the list.)^ 2759** 2760** See also: [sqlite3_bind_blob|sqlite3_bind()], 2761** [sqlite3_bind_parameter_name()], and 2762** [sqlite3_bind_parameter_index()]. 2763*/ 2764SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*); 2765 2766/* 2767** CAPI3REF: Name Of A Host Parameter 2768** 2769** ^The sqlite3_bind_parameter_name(P,N) interface returns 2770** the name of the N-th [SQL parameter] in the [prepared statement] P. 2771** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 2772** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 2773** respectively. 2774** In other words, the initial ":" or "$" or "@" or "?" 2775** is included as part of the name.)^ 2776** ^Parameters of the form "?" without a following integer have no name 2777** and are referred to as "nameless" or "anonymous parameters". 2778** 2779** ^The first host parameter has an index of 1, not 0. 2780** 2781** ^If the value N is out of range or if the N-th parameter is 2782** nameless, then NULL is returned. ^The returned string is 2783** always in UTF-8 encoding even if the named parameter was 2784** originally specified as UTF-16 in [sqlite3_prepare16()] or 2785** [sqlite3_prepare16_v2()]. 2786** 2787** See also: [sqlite3_bind_blob|sqlite3_bind()], 2788** [sqlite3_bind_parameter_count()], and 2789** [sqlite3_bind_parameter_index()]. 2790*/ 2791SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 2792 2793/* 2794** CAPI3REF: Index Of A Parameter With A Given Name 2795** 2796** ^Return the index of an SQL parameter given its name. ^The 2797** index value returned is suitable for use as the second 2798** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 2799** is returned if no matching parameter is found. ^The parameter 2800** name must be given in UTF-8 even if the original statement 2801** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. 2802** 2803** See also: [sqlite3_bind_blob|sqlite3_bind()], 2804** [sqlite3_bind_parameter_count()], and 2805** [sqlite3_bind_parameter_index()]. 2806*/ 2807SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 2808 2809/* 2810** CAPI3REF: Reset All Bindings On A Prepared Statement 2811** 2812** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 2813** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 2814** ^Use this routine to reset all host parameters to NULL. 2815*/ 2816SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*); 2817 2818/* 2819** CAPI3REF: Number Of Columns In A Result Set 2820** 2821** ^Return the number of columns in the result set returned by the 2822** [prepared statement]. ^This routine returns 0 if pStmt is an SQL 2823** statement that does not return data (for example an [UPDATE]). 2824*/ 2825SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt); 2826 2827/* 2828** CAPI3REF: Column Names In A Result Set 2829** 2830** ^These routines return the name assigned to a particular column 2831** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 2832** interface returns a pointer to a zero-terminated UTF-8 string 2833** and sqlite3_column_name16() returns a pointer to a zero-terminated 2834** UTF-16 string. ^The first parameter is the [prepared statement] 2835** that implements the [SELECT] statement. ^The second parameter is the 2836** column number. ^The leftmost column is number 0. 2837** 2838** ^The returned string pointer is valid until either the [prepared statement] 2839** is destroyed by [sqlite3_finalize()] or until the next call to 2840** sqlite3_column_name() or sqlite3_column_name16() on the same column. 2841** 2842** ^If sqlite3_malloc() fails during the processing of either routine 2843** (for example during a conversion from UTF-8 to UTF-16) then a 2844** NULL pointer is returned. 2845** 2846** ^The name of a result column is the value of the "AS" clause for 2847** that column, if there is an AS clause. If there is no AS clause 2848** then the name of the column is unspecified and may change from 2849** one release of SQLite to the next. 2850*/ 2851SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N); 2852SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N); 2853 2854/* 2855** CAPI3REF: Source Of Data In A Query Result 2856** 2857** ^These routines provide a means to determine the database, table, and 2858** table column that is the origin of a particular result column in 2859** [SELECT] statement. 2860** ^The name of the database or table or column can be returned as 2861** either a UTF-8 or UTF-16 string. ^The _database_ routines return 2862** the database name, the _table_ routines return the table name, and 2863** the origin_ routines return the column name. 2864** ^The returned string is valid until the [prepared statement] is destroyed 2865** using [sqlite3_finalize()] or until the same information is requested 2866** again in a different encoding. 2867** 2868** ^The names returned are the original un-aliased names of the 2869** database, table, and column. 2870** 2871** ^The first argument to these interfaces is a [prepared statement]. 2872** ^These functions return information about the Nth result column returned by 2873** the statement, where N is the second function argument. 2874** ^The left-most column is column 0 for these routines. 2875** 2876** ^If the Nth column returned by the statement is an expression or 2877** subquery and is not a column value, then all of these functions return 2878** NULL. ^These routine might also return NULL if a memory allocation error 2879** occurs. ^Otherwise, they return the name of the attached database, table, 2880** or column that query result column was extracted from. 2881** 2882** ^As with all other SQLite APIs, those whose names end with "16" return 2883** UTF-16 encoded strings and the other functions return UTF-8. 2884** 2885** ^These APIs are only available if the library was compiled with the 2886** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 2887** 2888** If two or more threads call one or more of these routines against the same 2889** prepared statement and column at the same time then the results are 2890** undefined. 2891** 2892** If two or more threads call one or more 2893** [sqlite3_column_database_name | column metadata interfaces] 2894** for the same [prepared statement] and result column 2895** at the same time then the results are undefined. 2896*/ 2897SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int); 2898SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 2899SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int); 2900SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 2901SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 2902SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 2903 2904/* 2905** CAPI3REF: Declared Datatype Of A Query Result 2906** 2907** ^(The first parameter is a [prepared statement]. 2908** If this statement is a [SELECT] statement and the Nth column of the 2909** returned result set of that [SELECT] is a table column (not an 2910** expression or subquery) then the declared type of the table 2911** column is returned.)^ ^If the Nth column of the result set is an 2912** expression or subquery, then a NULL pointer is returned. 2913** ^The returned string is always UTF-8 encoded. 2914** 2915** ^(For example, given the database schema: 2916** 2917** CREATE TABLE t1(c1 VARIANT); 2918** 2919** and the following statement to be compiled: 2920** 2921** SELECT c1 + 1, c1 FROM t1; 2922** 2923** this routine would return the string "VARIANT" for the second result 2924** column (i==1), and a NULL pointer for the first result column (i==0).)^ 2925** 2926** ^SQLite uses dynamic run-time typing. ^So just because a column 2927** is declared to contain a particular type does not mean that the 2928** data stored in that column is of the declared type. SQLite is 2929** strongly typed, but the typing is dynamic not static. ^Type 2930** is associated with individual values, not with the containers 2931** used to hold those values. 2932*/ 2933SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int); 2934SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 2935 2936/* 2937** CAPI3REF: Evaluate An SQL Statement 2938** 2939** After a [prepared statement] has been prepared using either 2940** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy 2941** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 2942** must be called one or more times to evaluate the statement. 2943** 2944** The details of the behavior of the sqlite3_step() interface depend 2945** on whether the statement was prepared using the newer "v2" interface 2946** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy 2947** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 2948** new "v2" interface is recommended for new applications but the legacy 2949** interface will continue to be supported. 2950** 2951** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 2952** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 2953** ^With the "v2" interface, any of the other [result codes] or 2954** [extended result codes] might be returned as well. 2955** 2956** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 2957** database locks it needs to do its job. ^If the statement is a [COMMIT] 2958** or occurs outside of an explicit transaction, then you can retry the 2959** statement. If the statement is not a [COMMIT] and occurs within a 2960** explicit transaction then you should rollback the transaction before 2961** continuing. 2962** 2963** ^[SQLITE_DONE] means that the statement has finished executing 2964** successfully. sqlite3_step() should not be called again on this virtual 2965** machine without first calling [sqlite3_reset()] to reset the virtual 2966** machine back to its initial state. 2967** 2968** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 2969** is returned each time a new row of data is ready for processing by the 2970** caller. The values may be accessed using the [column access functions]. 2971** sqlite3_step() is called again to retrieve the next row of data. 2972** 2973** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 2974** violation) has occurred. sqlite3_step() should not be called again on 2975** the VM. More information may be found by calling [sqlite3_errmsg()]. 2976** ^With the legacy interface, a more specific error code (for example, 2977** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 2978** can be obtained by calling [sqlite3_reset()] on the 2979** [prepared statement]. ^In the "v2" interface, 2980** the more specific error code is returned directly by sqlite3_step(). 2981** 2982** [SQLITE_MISUSE] means that the this routine was called inappropriately. 2983** Perhaps it was called on a [prepared statement] that has 2984** already been [sqlite3_finalize | finalized] or on one that had 2985** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 2986** be the case that the same database connection is being used by two or 2987** more threads at the same moment in time. 2988** 2989** For all versions of SQLite up to and including 3.6.23.1, it was required 2990** after sqlite3_step() returned anything other than [SQLITE_ROW] that 2991** [sqlite3_reset()] be called before any subsequent invocation of 2992** sqlite3_step(). Failure to invoke [sqlite3_reset()] in this way would 2993** result in an [SQLITE_MISUSE] return from sqlite3_step(). But after 2994** version 3.6.23.1, sqlite3_step() began calling [sqlite3_reset()] 2995** automatically in this circumstance rather than returning [SQLITE_MISUSE]. 2996** 2997** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 2998** API always returns a generic error code, [SQLITE_ERROR], following any 2999** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 3000** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 3001** specific [error codes] that better describes the error. 3002** We admit that this is a goofy design. The problem has been fixed 3003** with the "v2" interface. If you prepare all of your SQL statements 3004** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead 3005** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 3006** then the more specific [error codes] are returned directly 3007** by sqlite3_step(). The use of the "v2" interface is recommended. 3008*/ 3009SQLITE_API int sqlite3_step(sqlite3_stmt*); 3010 3011/* 3012** CAPI3REF: Number of columns in a result set 3013** 3014** ^The sqlite3_data_count(P) the number of columns in the 3015** of the result set of [prepared statement] P. 3016*/ 3017SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt); 3018 3019/* 3020** CAPI3REF: Fundamental Datatypes 3021** KEYWORDS: SQLITE_TEXT 3022** 3023** ^(Every value in SQLite has one of five fundamental datatypes: 3024** 3025** <ul> 3026** <li> 64-bit signed integer 3027** <li> 64-bit IEEE floating point number 3028** <li> string 3029** <li> BLOB 3030** <li> NULL 3031** </ul>)^ 3032** 3033** These constants are codes for each of those types. 3034** 3035** Note that the SQLITE_TEXT constant was also used in SQLite version 2 3036** for a completely different meaning. Software that links against both 3037** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 3038** SQLITE_TEXT. 3039*/ 3040#define SQLITE_INTEGER 1 3041#define SQLITE_FLOAT 2 3042#define SQLITE_BLOB 4 3043#define SQLITE_NULL 5 3044#ifdef SQLITE_TEXT 3045# undef SQLITE_TEXT 3046#else 3047# define SQLITE_TEXT 3 3048#endif 3049#define SQLITE3_TEXT 3 3050 3051/* 3052** CAPI3REF: Result Values From A Query 3053** KEYWORDS: {column access functions} 3054** 3055** These routines form the "result set" interface. 3056** 3057** ^These routines return information about a single column of the current 3058** result row of a query. ^In every case the first argument is a pointer 3059** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 3060** that was returned from [sqlite3_prepare_v2()] or one of its variants) 3061** and the second argument is the index of the column for which information 3062** should be returned. ^The leftmost column of the result set has the index 0. 3063** ^The number of columns in the result can be determined using 3064** [sqlite3_column_count()]. 3065** 3066** If the SQL statement does not currently point to a valid row, or if the 3067** column index is out of range, the result is undefined. 3068** These routines may only be called when the most recent call to 3069** [sqlite3_step()] has returned [SQLITE_ROW] and neither 3070** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 3071** If any of these routines are called after [sqlite3_reset()] or 3072** [sqlite3_finalize()] or after [sqlite3_step()] has returned 3073** something other than [SQLITE_ROW], the results are undefined. 3074** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 3075** are called from a different thread while any of these routines 3076** are pending, then the results are undefined. 3077** 3078** ^The sqlite3_column_type() routine returns the 3079** [SQLITE_INTEGER | datatype code] for the initial data type 3080** of the result column. ^The returned value is one of [SQLITE_INTEGER], 3081** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value 3082** returned by sqlite3_column_type() is only meaningful if no type 3083** conversions have occurred as described below. After a type conversion, 3084** the value returned by sqlite3_column_type() is undefined. Future 3085** versions of SQLite may change the behavior of sqlite3_column_type() 3086** following a type conversion. 3087** 3088** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 3089** routine returns the number of bytes in that BLOB or string. 3090** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 3091** the string to UTF-8 and then returns the number of bytes. 3092** ^If the result is a numeric value then sqlite3_column_bytes() uses 3093** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 3094** the number of bytes in that string. 3095** ^The value returned does not include the zero terminator at the end 3096** of the string. ^For clarity: the value returned is the number of 3097** bytes in the string, not the number of characters. 3098** 3099** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 3100** even empty strings, are always zero terminated. ^The return 3101** value from sqlite3_column_blob() for a zero-length BLOB is an arbitrary 3102** pointer, possibly even a NULL pointer. 3103** 3104** ^The sqlite3_column_bytes16() routine is similar to sqlite3_column_bytes() 3105** but leaves the result in UTF-16 in native byte order instead of UTF-8. 3106** ^The zero terminator is not included in this count. 3107** 3108** ^The object returned by [sqlite3_column_value()] is an 3109** [unprotected sqlite3_value] object. An unprotected sqlite3_value object 3110** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()]. 3111** If the [unprotected sqlite3_value] object returned by 3112** [sqlite3_column_value()] is used in any other way, including calls 3113** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 3114** or [sqlite3_value_bytes()], then the behavior is undefined. 3115** 3116** These routines attempt to convert the value where appropriate. ^For 3117** example, if the internal representation is FLOAT and a text result 3118** is requested, [sqlite3_snprintf()] is used internally to perform the 3119** conversion automatically. ^(The following table details the conversions 3120** that are applied: 3121** 3122** <blockquote> 3123** <table border="1"> 3124** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 3125** 3126** <tr><td> NULL <td> INTEGER <td> Result is 0 3127** <tr><td> NULL <td> FLOAT <td> Result is 0.0 3128** <tr><td> NULL <td> TEXT <td> Result is NULL pointer 3129** <tr><td> NULL <td> BLOB <td> Result is NULL pointer 3130** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 3131** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 3132** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 3133** <tr><td> FLOAT <td> INTEGER <td> Convert from float to integer 3134** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 3135** <tr><td> FLOAT <td> BLOB <td> Same as FLOAT->TEXT 3136** <tr><td> TEXT <td> INTEGER <td> Use atoi() 3137** <tr><td> TEXT <td> FLOAT <td> Use atof() 3138** <tr><td> TEXT <td> BLOB <td> No change 3139** <tr><td> BLOB <td> INTEGER <td> Convert to TEXT then use atoi() 3140** <tr><td> BLOB <td> FLOAT <td> Convert to TEXT then use atof() 3141** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 3142** </table> 3143** </blockquote>)^ 3144** 3145** The table above makes reference to standard C library functions atoi() 3146** and atof(). SQLite does not really use these functions. It has its 3147** own equivalent internal routines. The atoi() and atof() names are 3148** used in the table for brevity and because they are familiar to most 3149** C programmers. 3150** 3151** ^Note that when type conversions occur, pointers returned by prior 3152** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 3153** sqlite3_column_text16() may be invalidated. 3154** ^(Type conversions and pointer invalidations might occur 3155** in the following cases: 3156** 3157** <ul> 3158** <li> The initial content is a BLOB and sqlite3_column_text() or 3159** sqlite3_column_text16() is called. A zero-terminator might 3160** need to be added to the string.</li> 3161** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 3162** sqlite3_column_text16() is called. The content must be converted 3163** to UTF-16.</li> 3164** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 3165** sqlite3_column_text() is called. The content must be converted 3166** to UTF-8.</li> 3167** </ul>)^ 3168** 3169** ^Conversions between UTF-16be and UTF-16le are always done in place and do 3170** not invalidate a prior pointer, though of course the content of the buffer 3171** that the prior pointer points to will have been modified. Other kinds 3172** of conversion are done in place when it is possible, but sometimes they 3173** are not possible and in those cases prior pointers are invalidated. 3174** 3175** ^(The safest and easiest to remember policy is to invoke these routines 3176** in one of the following ways: 3177** 3178** <ul> 3179** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 3180** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 3181** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 3182** </ul>)^ 3183** 3184** In other words, you should call sqlite3_column_text(), 3185** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 3186** into the desired format, then invoke sqlite3_column_bytes() or 3187** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 3188** to sqlite3_column_text() or sqlite3_column_blob() with calls to 3189** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 3190** with calls to sqlite3_column_bytes(). 3191** 3192** ^The pointers returned are valid until a type conversion occurs as 3193** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 3194** [sqlite3_finalize()] is called. ^The memory space used to hold strings 3195** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned 3196** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 3197** [sqlite3_free()]. 3198** 3199** ^(If a memory allocation error occurs during the evaluation of any 3200** of these routines, a default value is returned. The default value 3201** is either the integer 0, the floating point number 0.0, or a NULL 3202** pointer. Subsequent calls to [sqlite3_errcode()] will return 3203** [SQLITE_NOMEM].)^ 3204*/ 3205SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 3206SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 3207SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 3208SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol); 3209SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol); 3210SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 3211SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 3212SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 3213SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol); 3214SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 3215 3216/* 3217** CAPI3REF: Destroy A Prepared Statement Object 3218** 3219** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 3220** ^If the statement was executed successfully or not executed at all, then 3221** SQLITE_OK is returned. ^If execution of the statement failed then an 3222** [error code] or [extended error code] is returned. 3223** 3224** ^This routine can be called at any point during the execution of the 3225** [prepared statement]. ^If the virtual machine has not 3226** completed execution when this routine is called, that is like 3227** encountering an error or an [sqlite3_interrupt | interrupt]. 3228** ^Incomplete updates may be rolled back and transactions canceled, 3229** depending on the circumstances, and the 3230** [error code] returned will be [SQLITE_ABORT]. 3231*/ 3232SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt); 3233 3234/* 3235** CAPI3REF: Reset A Prepared Statement Object 3236** 3237** The sqlite3_reset() function is called to reset a [prepared statement] 3238** object back to its initial state, ready to be re-executed. 3239** ^Any SQL statement variables that had values bound to them using 3240** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 3241** Use [sqlite3_clear_bindings()] to reset the bindings. 3242** 3243** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 3244** back to the beginning of its program. 3245** 3246** ^If the most recent call to [sqlite3_step(S)] for the 3247** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 3248** or if [sqlite3_step(S)] has never before been called on S, 3249** then [sqlite3_reset(S)] returns [SQLITE_OK]. 3250** 3251** ^If the most recent call to [sqlite3_step(S)] for the 3252** [prepared statement] S indicated an error, then 3253** [sqlite3_reset(S)] returns an appropriate [error code]. 3254** 3255** ^The [sqlite3_reset(S)] interface does not change the values 3256** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 3257*/ 3258SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt); 3259 3260/* 3261** CAPI3REF: Create Or Redefine SQL Functions 3262** KEYWORDS: {function creation routines} 3263** KEYWORDS: {application-defined SQL function} 3264** KEYWORDS: {application-defined SQL functions} 3265** 3266** ^These two functions (collectively known as "function creation routines") 3267** are used to add SQL functions or aggregates or to redefine the behavior 3268** of existing SQL functions or aggregates. The only difference between the 3269** two is that the second parameter, the name of the (scalar) function or 3270** aggregate, is encoded in UTF-8 for sqlite3_create_function() and UTF-16 3271** for sqlite3_create_function16(). 3272** 3273** ^The first parameter is the [database connection] to which the SQL 3274** function is to be added. ^If an application uses more than one database 3275** connection then application-defined SQL functions must be added 3276** to each database connection separately. 3277** 3278** The second parameter is the name of the SQL function to be created or 3279** redefined. ^The length of the name is limited to 255 bytes, exclusive of 3280** the zero-terminator. Note that the name length limit is in bytes, not 3281** characters. ^Any attempt to create a function with a longer name 3282** will result in [SQLITE_ERROR] being returned. 3283** 3284** ^The third parameter (nArg) 3285** is the number of arguments that the SQL function or 3286** aggregate takes. ^If this parameter is -1, then the SQL function or 3287** aggregate may take any number of arguments between 0 and the limit 3288** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 3289** parameter is less than -1 or greater than 127 then the behavior is 3290** undefined. 3291** 3292** The fourth parameter, eTextRep, specifies what 3293** [SQLITE_UTF8 | text encoding] this SQL function prefers for 3294** its parameters. Any SQL function implementation should be able to work 3295** work with UTF-8, UTF-16le, or UTF-16be. But some implementations may be 3296** more efficient with one encoding than another. ^An application may 3297** invoke sqlite3_create_function() or sqlite3_create_function16() multiple 3298** times with the same function but with different values of eTextRep. 3299** ^When multiple implementations of the same function are available, SQLite 3300** will pick the one that involves the least amount of data conversion. 3301** If there is only a single implementation which does not care what text 3302** encoding is used, then the fourth argument should be [SQLITE_ANY]. 3303** 3304** ^(The fifth parameter is an arbitrary pointer. The implementation of the 3305** function can gain access to this pointer using [sqlite3_user_data()].)^ 3306** 3307** The seventh, eighth and ninth parameters, xFunc, xStep and xFinal, are 3308** pointers to C-language functions that implement the SQL function or 3309** aggregate. ^A scalar SQL function requires an implementation of the xFunc 3310** callback only; NULL pointers should be passed as the xStep and xFinal 3311** parameters. ^An aggregate SQL function requires an implementation of xStep 3312** and xFinal and NULL should be passed for xFunc. ^To delete an existing 3313** SQL function or aggregate, pass NULL for all three function callbacks. 3314** 3315** ^It is permitted to register multiple implementations of the same 3316** functions with the same name but with either differing numbers of 3317** arguments or differing preferred text encodings. ^SQLite will use 3318** the implementation that most closely matches the way in which the 3319** SQL function is used. ^A function implementation with a non-negative 3320** nArg parameter is a better match than a function implementation with 3321** a negative nArg. ^A function where the preferred text encoding 3322** matches the database encoding is a better 3323** match than a function where the encoding is different. 3324** ^A function where the encoding difference is between UTF16le and UTF16be 3325** is a closer match than a function where the encoding difference is 3326** between UTF8 and UTF16. 3327** 3328** ^Built-in functions may be overloaded by new application-defined functions. 3329** ^The first application-defined function with a given name overrides all 3330** built-in functions in the same [database connection] with the same name. 3331** ^Subsequent application-defined functions of the same name only override 3332** prior application-defined functions that are an exact match for the 3333** number of parameters and preferred encoding. 3334** 3335** ^An application-defined function is permitted to call other 3336** SQLite interfaces. However, such calls must not 3337** close the database connection nor finalize or reset the prepared 3338** statement in which the function is running. 3339*/ 3340SQLITE_API int sqlite3_create_function( 3341 sqlite3 *db, 3342 const char *zFunctionName, 3343 int nArg, 3344 int eTextRep, 3345 void *pApp, 3346 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3347 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3348 void (*xFinal)(sqlite3_context*) 3349); 3350SQLITE_API int sqlite3_create_function16( 3351 sqlite3 *db, 3352 const void *zFunctionName, 3353 int nArg, 3354 int eTextRep, 3355 void *pApp, 3356 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3357 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3358 void (*xFinal)(sqlite3_context*) 3359); 3360 3361/* 3362** CAPI3REF: Text Encodings 3363** 3364** These constant define integer codes that represent the various 3365** text encodings supported by SQLite. 3366*/ 3367#define SQLITE_UTF8 1 3368#define SQLITE_UTF16LE 2 3369#define SQLITE_UTF16BE 3 3370#define SQLITE_UTF16 4 /* Use native byte order */ 3371#define SQLITE_ANY 5 /* sqlite3_create_function only */ 3372#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 3373 3374/* 3375** CAPI3REF: Deprecated Functions 3376** DEPRECATED 3377** 3378** These functions are [deprecated]. In order to maintain 3379** backwards compatibility with older code, these functions continue 3380** to be supported. However, new applications should avoid 3381** the use of these functions. To help encourage people to avoid 3382** using these functions, we are not going to tell you what they do. 3383*/ 3384#ifndef SQLITE_OMIT_DEPRECATED 3385SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 3386SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 3387SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 3388SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void); 3389SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 3390SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64); 3391#endif 3392 3393/* 3394** CAPI3REF: Obtaining SQL Function Parameter Values 3395** 3396** The C-language implementation of SQL functions and aggregates uses 3397** this set of interface routines to access the parameter values on 3398** the function or aggregate. 3399** 3400** The xFunc (for scalar functions) or xStep (for aggregates) parameters 3401** to [sqlite3_create_function()] and [sqlite3_create_function16()] 3402** define callbacks that implement the SQL functions and aggregates. 3403** The 4th parameter to these callbacks is an array of pointers to 3404** [protected sqlite3_value] objects. There is one [sqlite3_value] object for 3405** each parameter to the SQL function. These routines are used to 3406** extract values from the [sqlite3_value] objects. 3407** 3408** These routines work only with [protected sqlite3_value] objects. 3409** Any attempt to use these routines on an [unprotected sqlite3_value] 3410** object results in undefined behavior. 3411** 3412** ^These routines work just like the corresponding [column access functions] 3413** except that these routines take a single [protected sqlite3_value] object 3414** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 3415** 3416** ^The sqlite3_value_text16() interface extracts a UTF-16 string 3417** in the native byte-order of the host machine. ^The 3418** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 3419** extract UTF-16 strings as big-endian and little-endian respectively. 3420** 3421** ^(The sqlite3_value_numeric_type() interface attempts to apply 3422** numeric affinity to the value. This means that an attempt is 3423** made to convert the value to an integer or floating point. If 3424** such a conversion is possible without loss of information (in other 3425** words, if the value is a string that looks like a number) 3426** then the conversion is performed. Otherwise no conversion occurs. 3427** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 3428** 3429** Please pay particular attention to the fact that the pointer returned 3430** from [sqlite3_value_blob()], [sqlite3_value_text()], or 3431** [sqlite3_value_text16()] can be invalidated by a subsequent call to 3432** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 3433** or [sqlite3_value_text16()]. 3434** 3435** These routines must be called from the same thread as 3436** the SQL function that supplied the [sqlite3_value*] parameters. 3437*/ 3438SQLITE_API const void *sqlite3_value_blob(sqlite3_value*); 3439SQLITE_API int sqlite3_value_bytes(sqlite3_value*); 3440SQLITE_API int sqlite3_value_bytes16(sqlite3_value*); 3441SQLITE_API double sqlite3_value_double(sqlite3_value*); 3442SQLITE_API int sqlite3_value_int(sqlite3_value*); 3443SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 3444SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*); 3445SQLITE_API const void *sqlite3_value_text16(sqlite3_value*); 3446SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*); 3447SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*); 3448SQLITE_API int sqlite3_value_type(sqlite3_value*); 3449SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*); 3450 3451/* 3452** CAPI3REF: Obtain Aggregate Function Context 3453** 3454** Implementations of aggregate SQL functions use this 3455** routine to allocate memory for storing their state. 3456** 3457** ^The first time the sqlite3_aggregate_context(C,N) routine is called 3458** for a particular aggregate function, SQLite 3459** allocates N of memory, zeroes out that memory, and returns a pointer 3460** to the new memory. ^On second and subsequent calls to 3461** sqlite3_aggregate_context() for the same aggregate function instance, 3462** the same buffer is returned. Sqlite3_aggregate_context() is normally 3463** called once for each invocation of the xStep callback and then one 3464** last time when the xFinal callback is invoked. ^(When no rows match 3465** an aggregate query, the xStep() callback of the aggregate function 3466** implementation is never called and xFinal() is called exactly once. 3467** In those cases, sqlite3_aggregate_context() might be called for the 3468** first time from within xFinal().)^ 3469** 3470** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer if N is 3471** less than or equal to zero or if a memory allocate error occurs. 3472** 3473** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 3474** determined by the N parameter on first successful call. Changing the 3475** value of N in subsequent call to sqlite3_aggregate_context() within 3476** the same aggregate function instance will not resize the memory 3477** allocation.)^ 3478** 3479** ^SQLite automatically frees the memory allocated by 3480** sqlite3_aggregate_context() when the aggregate query concludes. 3481** 3482** The first parameter must be a copy of the 3483** [sqlite3_context | SQL function context] that is the first parameter 3484** to the xStep or xFinal callback routine that implements the aggregate 3485** function. 3486** 3487** This routine must be called from the same thread in which 3488** the aggregate SQL function is running. 3489*/ 3490SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 3491 3492/* 3493** CAPI3REF: User Data For Functions 3494** 3495** ^The sqlite3_user_data() interface returns a copy of 3496** the pointer that was the pUserData parameter (the 5th parameter) 3497** of the [sqlite3_create_function()] 3498** and [sqlite3_create_function16()] routines that originally 3499** registered the application defined function. 3500** 3501** This routine must be called from the same thread in which 3502** the application-defined function is running. 3503*/ 3504SQLITE_API void *sqlite3_user_data(sqlite3_context*); 3505 3506/* 3507** CAPI3REF: Database Connection For Functions 3508** 3509** ^The sqlite3_context_db_handle() interface returns a copy of 3510** the pointer to the [database connection] (the 1st parameter) 3511** of the [sqlite3_create_function()] 3512** and [sqlite3_create_function16()] routines that originally 3513** registered the application defined function. 3514*/ 3515SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 3516 3517/* 3518** CAPI3REF: Function Auxiliary Data 3519** 3520** The following two functions may be used by scalar SQL functions to 3521** associate metadata with argument values. If the same value is passed to 3522** multiple invocations of the same SQL function during query execution, under 3523** some circumstances the associated metadata may be preserved. This may 3524** be used, for example, to add a regular-expression matching scalar 3525** function. The compiled version of the regular expression is stored as 3526** metadata associated with the SQL value passed as the regular expression 3527** pattern. The compiled regular expression can be reused on multiple 3528** invocations of the same function so that the original pattern string 3529** does not need to be recompiled on each invocation. 3530** 3531** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata 3532** associated by the sqlite3_set_auxdata() function with the Nth argument 3533** value to the application-defined function. ^If no metadata has been ever 3534** been set for the Nth argument of the function, or if the corresponding 3535** function parameter has changed since the meta-data was set, 3536** then sqlite3_get_auxdata() returns a NULL pointer. 3537** 3538** ^The sqlite3_set_auxdata() interface saves the metadata 3539** pointed to by its 3rd parameter as the metadata for the N-th 3540** argument of the application-defined function. Subsequent 3541** calls to sqlite3_get_auxdata() might return this data, if it has 3542** not been destroyed. 3543** ^If it is not NULL, SQLite will invoke the destructor 3544** function given by the 4th parameter to sqlite3_set_auxdata() on 3545** the metadata when the corresponding function parameter changes 3546** or when the SQL statement completes, whichever comes first. 3547** 3548** SQLite is free to call the destructor and drop metadata on any 3549** parameter of any function at any time. ^The only guarantee is that 3550** the destructor will be called before the metadata is dropped. 3551** 3552** ^(In practice, metadata is preserved between function calls for 3553** expressions that are constant at compile time. This includes literal 3554** values and [parameters].)^ 3555** 3556** These routines must be called from the same thread in which 3557** the SQL function is running. 3558*/ 3559SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N); 3560SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 3561 3562 3563/* 3564** CAPI3REF: Constants Defining Special Destructor Behavior 3565** 3566** These are special values for the destructor that is passed in as the 3567** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 3568** argument is SQLITE_STATIC, it means that the content pointer is constant 3569** and will never change. It does not need to be destroyed. ^The 3570** SQLITE_TRANSIENT value means that the content will likely change in 3571** the near future and that SQLite should make its own private copy of 3572** the content before returning. 3573** 3574** The typedef is necessary to work around problems in certain 3575** C++ compilers. See ticket #2191. 3576*/ 3577typedef void (*sqlite3_destructor_type)(void*); 3578#define SQLITE_STATIC ((sqlite3_destructor_type)0) 3579#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 3580 3581/* 3582** CAPI3REF: Setting The Result Of An SQL Function 3583** 3584** These routines are used by the xFunc or xFinal callbacks that 3585** implement SQL functions and aggregates. See 3586** [sqlite3_create_function()] and [sqlite3_create_function16()] 3587** for additional information. 3588** 3589** These functions work very much like the [parameter binding] family of 3590** functions used to bind values to host parameters in prepared statements. 3591** Refer to the [SQL parameter] documentation for additional information. 3592** 3593** ^The sqlite3_result_blob() interface sets the result from 3594** an application-defined function to be the BLOB whose content is pointed 3595** to by the second parameter and which is N bytes long where N is the 3596** third parameter. 3597** 3598** ^The sqlite3_result_zeroblob() interfaces set the result of 3599** the application-defined function to be a BLOB containing all zero 3600** bytes and N bytes in size, where N is the value of the 2nd parameter. 3601** 3602** ^The sqlite3_result_double() interface sets the result from 3603** an application-defined function to be a floating point value specified 3604** by its 2nd argument. 3605** 3606** ^The sqlite3_result_error() and sqlite3_result_error16() functions 3607** cause the implemented SQL function to throw an exception. 3608** ^SQLite uses the string pointed to by the 3609** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 3610** as the text of an error message. ^SQLite interprets the error 3611** message string from sqlite3_result_error() as UTF-8. ^SQLite 3612** interprets the string from sqlite3_result_error16() as UTF-16 in native 3613** byte order. ^If the third parameter to sqlite3_result_error() 3614** or sqlite3_result_error16() is negative then SQLite takes as the error 3615** message all text up through the first zero character. 3616** ^If the third parameter to sqlite3_result_error() or 3617** sqlite3_result_error16() is non-negative then SQLite takes that many 3618** bytes (not characters) from the 2nd parameter as the error message. 3619** ^The sqlite3_result_error() and sqlite3_result_error16() 3620** routines make a private copy of the error message text before 3621** they return. Hence, the calling function can deallocate or 3622** modify the text after they return without harm. 3623** ^The sqlite3_result_error_code() function changes the error code 3624** returned by SQLite as a result of an error in a function. ^By default, 3625** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 3626** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 3627** 3628** ^The sqlite3_result_toobig() interface causes SQLite to throw an error 3629** indicating that a string or BLOB is too long to represent. 3630** 3631** ^The sqlite3_result_nomem() interface causes SQLite to throw an error 3632** indicating that a memory allocation failed. 3633** 3634** ^The sqlite3_result_int() interface sets the return value 3635** of the application-defined function to be the 32-bit signed integer 3636** value given in the 2nd argument. 3637** ^The sqlite3_result_int64() interface sets the return value 3638** of the application-defined function to be the 64-bit signed integer 3639** value given in the 2nd argument. 3640** 3641** ^The sqlite3_result_null() interface sets the return value 3642** of the application-defined function to be NULL. 3643** 3644** ^The sqlite3_result_text(), sqlite3_result_text16(), 3645** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 3646** set the return value of the application-defined function to be 3647** a text string which is represented as UTF-8, UTF-16 native byte order, 3648** UTF-16 little endian, or UTF-16 big endian, respectively. 3649** ^SQLite takes the text result from the application from 3650** the 2nd parameter of the sqlite3_result_text* interfaces. 3651** ^If the 3rd parameter to the sqlite3_result_text* interfaces 3652** is negative, then SQLite takes result text from the 2nd parameter 3653** through the first zero character. 3654** ^If the 3rd parameter to the sqlite3_result_text* interfaces 3655** is non-negative, then as many bytes (not characters) of the text 3656** pointed to by the 2nd parameter are taken as the application-defined 3657** function result. 3658** ^If the 4th parameter to the sqlite3_result_text* interfaces 3659** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 3660** function as the destructor on the text or BLOB result when it has 3661** finished using that result. 3662** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 3663** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 3664** assumes that the text or BLOB result is in constant space and does not 3665** copy the content of the parameter nor call a destructor on the content 3666** when it has finished using that result. 3667** ^If the 4th parameter to the sqlite3_result_text* interfaces 3668** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 3669** then SQLite makes a copy of the result into space obtained from 3670** from [sqlite3_malloc()] before it returns. 3671** 3672** ^The sqlite3_result_value() interface sets the result of 3673** the application-defined function to be a copy the 3674** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 3675** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 3676** so that the [sqlite3_value] specified in the parameter may change or 3677** be deallocated after sqlite3_result_value() returns without harm. 3678** ^A [protected sqlite3_value] object may always be used where an 3679** [unprotected sqlite3_value] object is required, so either 3680** kind of [sqlite3_value] object can be used with this interface. 3681** 3682** If these routines are called from within the different thread 3683** than the one containing the application-defined function that received 3684** the [sqlite3_context] pointer, the results are undefined. 3685*/ 3686SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 3687SQLITE_API void sqlite3_result_double(sqlite3_context*, double); 3688SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int); 3689SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int); 3690SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*); 3691SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*); 3692SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int); 3693SQLITE_API void sqlite3_result_int(sqlite3_context*, int); 3694SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 3695SQLITE_API void sqlite3_result_null(sqlite3_context*); 3696SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 3697SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 3698SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 3699SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 3700SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 3701SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n); 3702 3703/* 3704** CAPI3REF: Define New Collating Sequences 3705** 3706** These functions are used to add new collation sequences to the 3707** [database connection] specified as the first argument. 3708** 3709** ^The name of the new collation sequence is specified as a UTF-8 string 3710** for sqlite3_create_collation() and sqlite3_create_collation_v2() 3711** and a UTF-16 string for sqlite3_create_collation16(). ^In all cases 3712** the name is passed as the second function argument. 3713** 3714** ^The third argument may be one of the constants [SQLITE_UTF8], 3715** [SQLITE_UTF16LE], or [SQLITE_UTF16BE], indicating that the user-supplied 3716** routine expects to be passed pointers to strings encoded using UTF-8, 3717** UTF-16 little-endian, or UTF-16 big-endian, respectively. ^The 3718** third argument might also be [SQLITE_UTF16] to indicate that the routine 3719** expects pointers to be UTF-16 strings in the native byte order, or the 3720** argument can be [SQLITE_UTF16_ALIGNED] if the 3721** the routine expects pointers to 16-bit word aligned strings 3722** of UTF-16 in the native byte order. 3723** 3724** A pointer to the user supplied routine must be passed as the fifth 3725** argument. ^If it is NULL, this is the same as deleting the collation 3726** sequence (so that SQLite cannot call it any more). 3727** ^Each time the application supplied function is invoked, it is passed 3728** as its first parameter a copy of the void* passed as the fourth argument 3729** to sqlite3_create_collation() or sqlite3_create_collation16(). 3730** 3731** ^The remaining arguments to the application-supplied routine are two strings, 3732** each represented by a (length, data) pair and encoded in the encoding 3733** that was passed as the third argument when the collation sequence was 3734** registered. The application defined collation routine should 3735** return negative, zero or positive if the first string is less than, 3736** equal to, or greater than the second string. i.e. (STRING1 - STRING2). 3737** 3738** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 3739** except that it takes an extra argument which is a destructor for 3740** the collation. ^The destructor is called when the collation is 3741** destroyed and is passed a copy of the fourth parameter void* pointer 3742** of the sqlite3_create_collation_v2(). 3743** ^Collations are destroyed when they are overridden by later calls to the 3744** collation creation functions or when the [database connection] is closed 3745** using [sqlite3_close()]. 3746** 3747** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 3748*/ 3749SQLITE_API int sqlite3_create_collation( 3750 sqlite3*, 3751 const char *zName, 3752 int eTextRep, 3753 void*, 3754 int(*xCompare)(void*,int,const void*,int,const void*) 3755); 3756SQLITE_API int sqlite3_create_collation_v2( 3757 sqlite3*, 3758 const char *zName, 3759 int eTextRep, 3760 void*, 3761 int(*xCompare)(void*,int,const void*,int,const void*), 3762 void(*xDestroy)(void*) 3763); 3764SQLITE_API int sqlite3_create_collation16( 3765 sqlite3*, 3766 const void *zName, 3767 int eTextRep, 3768 void*, 3769 int(*xCompare)(void*,int,const void*,int,const void*) 3770); 3771 3772/* 3773** CAPI3REF: Collation Needed Callbacks 3774** 3775** ^To avoid having to register all collation sequences before a database 3776** can be used, a single callback function may be registered with the 3777** [database connection] to be invoked whenever an undefined collation 3778** sequence is required. 3779** 3780** ^If the function is registered using the sqlite3_collation_needed() API, 3781** then it is passed the names of undefined collation sequences as strings 3782** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 3783** the names are passed as UTF-16 in machine native byte order. 3784** ^A call to either function replaces the existing collation-needed callback. 3785** 3786** ^(When the callback is invoked, the first argument passed is a copy 3787** of the second argument to sqlite3_collation_needed() or 3788** sqlite3_collation_needed16(). The second argument is the database 3789** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 3790** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 3791** sequence function required. The fourth parameter is the name of the 3792** required collation sequence.)^ 3793** 3794** The callback function should register the desired collation using 3795** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 3796** [sqlite3_create_collation_v2()]. 3797*/ 3798SQLITE_API int sqlite3_collation_needed( 3799 sqlite3*, 3800 void*, 3801 void(*)(void*,sqlite3*,int eTextRep,const char*) 3802); 3803SQLITE_API int sqlite3_collation_needed16( 3804 sqlite3*, 3805 void*, 3806 void(*)(void*,sqlite3*,int eTextRep,const void*) 3807); 3808 3809#ifdef SQLITE_HAS_CODEC 3810/* 3811** Specify the key for an encrypted database. This routine should be 3812** called right after sqlite3_open(). 3813** 3814** The code to implement this API is not available in the public release 3815** of SQLite. 3816*/ 3817SQLITE_API int sqlite3_key( 3818 sqlite3 *db, /* Database to be rekeyed */ 3819 const void *pKey, int nKey /* The key */ 3820); 3821 3822/* 3823** Change the key on an open database. If the current database is not 3824** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 3825** database is decrypted. 3826** 3827** The code to implement this API is not available in the public release 3828** of SQLite. 3829*/ 3830SQLITE_API int sqlite3_rekey( 3831 sqlite3 *db, /* Database to be rekeyed */ 3832 const void *pKey, int nKey /* The new key */ 3833); 3834 3835/* 3836** Specify the activation key for a SEE database. Unless 3837** activated, none of the SEE routines will work. 3838*/ 3839SQLITE_API void sqlite3_activate_see( 3840 const char *zPassPhrase /* Activation phrase */ 3841); 3842#endif 3843 3844#ifdef SQLITE_ENABLE_CEROD 3845/* 3846** Specify the activation key for a CEROD database. Unless 3847** activated, none of the CEROD routines will work. 3848*/ 3849SQLITE_API void sqlite3_activate_cerod( 3850 const char *zPassPhrase /* Activation phrase */ 3851); 3852#endif 3853 3854/* 3855** CAPI3REF: Suspend Execution For A Short Time 3856** 3857** ^The sqlite3_sleep() function causes the current thread to suspend execution 3858** for at least a number of milliseconds specified in its parameter. 3859** 3860** ^If the operating system does not support sleep requests with 3861** millisecond time resolution, then the time will be rounded up to 3862** the nearest second. ^The number of milliseconds of sleep actually 3863** requested from the operating system is returned. 3864** 3865** ^SQLite implements this interface by calling the xSleep() 3866** method of the default [sqlite3_vfs] object. 3867*/ 3868SQLITE_API int sqlite3_sleep(int); 3869 3870/* 3871** CAPI3REF: Name Of The Folder Holding Temporary Files 3872** 3873** ^(If this global variable is made to point to a string which is 3874** the name of a folder (a.k.a. directory), then all temporary files 3875** created by SQLite when using a built-in [sqlite3_vfs | VFS] 3876** will be placed in that directory.)^ ^If this variable 3877** is a NULL pointer, then SQLite performs a search for an appropriate 3878** temporary file directory. 3879** 3880** It is not safe to read or modify this variable in more than one 3881** thread at a time. It is not safe to read or modify this variable 3882** if a [database connection] is being used at the same time in a separate 3883** thread. 3884** It is intended that this variable be set once 3885** as part of process initialization and before any SQLite interface 3886** routines have been called and that this variable remain unchanged 3887** thereafter. 3888** 3889** ^The [temp_store_directory pragma] may modify this variable and cause 3890** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 3891** the [temp_store_directory pragma] always assumes that any string 3892** that this variable points to is held in memory obtained from 3893** [sqlite3_malloc] and the pragma may attempt to free that memory 3894** using [sqlite3_free]. 3895** Hence, if this variable is modified directly, either it should be 3896** made NULL or made to point to memory obtained from [sqlite3_malloc] 3897** or else the use of the [temp_store_directory pragma] should be avoided. 3898*/ 3899SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory; 3900 3901/* 3902** CAPI3REF: Test For Auto-Commit Mode 3903** KEYWORDS: {autocommit mode} 3904** 3905** ^The sqlite3_get_autocommit() interface returns non-zero or 3906** zero if the given database connection is or is not in autocommit mode, 3907** respectively. ^Autocommit mode is on by default. 3908** ^Autocommit mode is disabled by a [BEGIN] statement. 3909** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 3910** 3911** If certain kinds of errors occur on a statement within a multi-statement 3912** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 3913** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 3914** transaction might be rolled back automatically. The only way to 3915** find out whether SQLite automatically rolled back the transaction after 3916** an error is to use this function. 3917** 3918** If another thread changes the autocommit status of the database 3919** connection while this routine is running, then the return value 3920** is undefined. 3921*/ 3922SQLITE_API int sqlite3_get_autocommit(sqlite3*); 3923 3924/* 3925** CAPI3REF: Find The Database Handle Of A Prepared Statement 3926** 3927** ^The sqlite3_db_handle interface returns the [database connection] handle 3928** to which a [prepared statement] belongs. ^The [database connection] 3929** returned by sqlite3_db_handle is the same [database connection] 3930** that was the first argument 3931** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 3932** create the statement in the first place. 3933*/ 3934SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 3935 3936/* 3937** CAPI3REF: Find the next prepared statement 3938** 3939** ^This interface returns a pointer to the next [prepared statement] after 3940** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 3941** then this interface returns a pointer to the first prepared statement 3942** associated with the database connection pDb. ^If no prepared statement 3943** satisfies the conditions of this routine, it returns NULL. 3944** 3945** The [database connection] pointer D in a call to 3946** [sqlite3_next_stmt(D,S)] must refer to an open database 3947** connection and in particular must not be a NULL pointer. 3948*/ 3949SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 3950 3951/* 3952** CAPI3REF: Commit And Rollback Notification Callbacks 3953** 3954** ^The sqlite3_commit_hook() interface registers a callback 3955** function to be invoked whenever a transaction is [COMMIT | committed]. 3956** ^Any callback set by a previous call to sqlite3_commit_hook() 3957** for the same database connection is overridden. 3958** ^The sqlite3_rollback_hook() interface registers a callback 3959** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 3960** ^Any callback set by a previous call to sqlite3_rollback_hook() 3961** for the same database connection is overridden. 3962** ^The pArg argument is passed through to the callback. 3963** ^If the callback on a commit hook function returns non-zero, 3964** then the commit is converted into a rollback. 3965** 3966** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 3967** return the P argument from the previous call of the same function 3968** on the same [database connection] D, or NULL for 3969** the first call for each function on D. 3970** 3971** The callback implementation must not do anything that will modify 3972** the database connection that invoked the callback. Any actions 3973** to modify the database connection must be deferred until after the 3974** completion of the [sqlite3_step()] call that triggered the commit 3975** or rollback hook in the first place. 3976** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3977** database connections for the meaning of "modify" in this paragraph. 3978** 3979** ^Registering a NULL function disables the callback. 3980** 3981** ^When the commit hook callback routine returns zero, the [COMMIT] 3982** operation is allowed to continue normally. ^If the commit hook 3983** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 3984** ^The rollback hook is invoked on a rollback that results from a commit 3985** hook returning non-zero, just as it would be with any other rollback. 3986** 3987** ^For the purposes of this API, a transaction is said to have been 3988** rolled back if an explicit "ROLLBACK" statement is executed, or 3989** an error or constraint causes an implicit rollback to occur. 3990** ^The rollback callback is not invoked if a transaction is 3991** automatically rolled back because the database connection is closed. 3992** 3993** See also the [sqlite3_update_hook()] interface. 3994*/ 3995SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 3996SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 3997 3998/* 3999** CAPI3REF: Data Change Notification Callbacks 4000** 4001** ^The sqlite3_update_hook() interface registers a callback function 4002** with the [database connection] identified by the first argument 4003** to be invoked whenever a row is updated, inserted or deleted. 4004** ^Any callback set by a previous call to this function 4005** for the same database connection is overridden. 4006** 4007** ^The second argument is a pointer to the function to invoke when a 4008** row is updated, inserted or deleted. 4009** ^The first argument to the callback is a copy of the third argument 4010** to sqlite3_update_hook(). 4011** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 4012** or [SQLITE_UPDATE], depending on the operation that caused the callback 4013** to be invoked. 4014** ^The third and fourth arguments to the callback contain pointers to the 4015** database and table name containing the affected row. 4016** ^The final callback parameter is the [rowid] of the row. 4017** ^In the case of an update, this is the [rowid] after the update takes place. 4018** 4019** ^(The update hook is not invoked when internal system tables are 4020** modified (i.e. sqlite_master and sqlite_sequence).)^ 4021** 4022** ^In the current implementation, the update hook 4023** is not invoked when duplication rows are deleted because of an 4024** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 4025** invoked when rows are deleted using the [truncate optimization]. 4026** The exceptions defined in this paragraph might change in a future 4027** release of SQLite. 4028** 4029** The update hook implementation must not do anything that will modify 4030** the database connection that invoked the update hook. Any actions 4031** to modify the database connection must be deferred until after the 4032** completion of the [sqlite3_step()] call that triggered the update hook. 4033** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 4034** database connections for the meaning of "modify" in this paragraph. 4035** 4036** ^The sqlite3_update_hook(D,C,P) function 4037** returns the P argument from the previous call 4038** on the same [database connection] D, or NULL for 4039** the first call on D. 4040** 4041** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()] 4042** interfaces. 4043*/ 4044SQLITE_API void *sqlite3_update_hook( 4045 sqlite3*, 4046 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 4047 void* 4048); 4049 4050/* 4051** CAPI3REF: Enable Or Disable Shared Pager Cache 4052** KEYWORDS: {shared cache} 4053** 4054** ^(This routine enables or disables the sharing of the database cache 4055** and schema data structures between [database connection | connections] 4056** to the same database. Sharing is enabled if the argument is true 4057** and disabled if the argument is false.)^ 4058** 4059** ^Cache sharing is enabled and disabled for an entire process. 4060** This is a change as of SQLite version 3.5.0. In prior versions of SQLite, 4061** sharing was enabled or disabled for each thread separately. 4062** 4063** ^(The cache sharing mode set by this interface effects all subsequent 4064** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 4065** Existing database connections continue use the sharing mode 4066** that was in effect at the time they were opened.)^ 4067** 4068** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 4069** successfully. An [error code] is returned otherwise.)^ 4070** 4071** ^Shared cache is disabled by default. But this might change in 4072** future releases of SQLite. Applications that care about shared 4073** cache setting should set it explicitly. 4074** 4075** See Also: [SQLite Shared-Cache Mode] 4076*/ 4077SQLITE_API int sqlite3_enable_shared_cache(int); 4078 4079/* 4080** CAPI3REF: Attempt To Free Heap Memory 4081** 4082** ^The sqlite3_release_memory() interface attempts to free N bytes 4083** of heap memory by deallocating non-essential memory allocations 4084** held by the database library. Memory used to cache database 4085** pages to improve performance is an example of non-essential memory. 4086** ^sqlite3_release_memory() returns the number of bytes actually freed, 4087** which might be more or less than the amount requested. 4088*/ 4089SQLITE_API int sqlite3_release_memory(int); 4090 4091/* 4092** CAPI3REF: Impose A Limit On Heap Size 4093** 4094** ^The sqlite3_soft_heap_limit() interface places a "soft" limit 4095** on the amount of heap memory that may be allocated by SQLite. 4096** ^If an internal allocation is requested that would exceed the 4097** soft heap limit, [sqlite3_release_memory()] is invoked one or 4098** more times to free up some space before the allocation is performed. 4099** 4100** ^The limit is called "soft" because if [sqlite3_release_memory()] 4101** cannot free sufficient memory to prevent the limit from being exceeded, 4102** the memory is allocated anyway and the current operation proceeds. 4103** 4104** ^A negative or zero value for N means that there is no soft heap limit and 4105** [sqlite3_release_memory()] will only be called when memory is exhausted. 4106** ^The default value for the soft heap limit is zero. 4107** 4108** ^(SQLite makes a best effort to honor the soft heap limit. 4109** But if the soft heap limit cannot be honored, execution will 4110** continue without error or notification.)^ This is why the limit is 4111** called a "soft" limit. It is advisory only. 4112** 4113** Prior to SQLite version 3.5.0, this routine only constrained the memory 4114** allocated by a single thread - the same thread in which this routine 4115** runs. Beginning with SQLite version 3.5.0, the soft heap limit is 4116** applied to all threads. The value specified for the soft heap limit 4117** is an upper bound on the total memory allocation for all threads. In 4118** version 3.5.0 there is no mechanism for limiting the heap usage for 4119** individual threads. 4120*/ 4121SQLITE_API void sqlite3_soft_heap_limit(int); 4122 4123/* 4124** CAPI3REF: Extract Metadata About A Column Of A Table 4125** 4126** ^This routine returns metadata about a specific column of a specific 4127** database table accessible using the [database connection] handle 4128** passed as the first function argument. 4129** 4130** ^The column is identified by the second, third and fourth parameters to 4131** this function. ^The second parameter is either the name of the database 4132** (i.e. "main", "temp", or an attached database) containing the specified 4133** table or NULL. ^If it is NULL, then all attached databases are searched 4134** for the table using the same algorithm used by the database engine to 4135** resolve unqualified table references. 4136** 4137** ^The third and fourth parameters to this function are the table and column 4138** name of the desired column, respectively. Neither of these parameters 4139** may be NULL. 4140** 4141** ^Metadata is returned by writing to the memory locations passed as the 5th 4142** and subsequent parameters to this function. ^Any of these arguments may be 4143** NULL, in which case the corresponding element of metadata is omitted. 4144** 4145** ^(<blockquote> 4146** <table border="1"> 4147** <tr><th> Parameter <th> Output<br>Type <th> Description 4148** 4149** <tr><td> 5th <td> const char* <td> Data type 4150** <tr><td> 6th <td> const char* <td> Name of default collation sequence 4151** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 4152** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 4153** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 4154** </table> 4155** </blockquote>)^ 4156** 4157** ^The memory pointed to by the character pointers returned for the 4158** declaration type and collation sequence is valid only until the next 4159** call to any SQLite API function. 4160** 4161** ^If the specified table is actually a view, an [error code] is returned. 4162** 4163** ^If the specified column is "rowid", "oid" or "_rowid_" and an 4164** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 4165** parameters are set for the explicitly declared column. ^(If there is no 4166** explicitly declared [INTEGER PRIMARY KEY] column, then the output 4167** parameters are set as follows: 4168** 4169** <pre> 4170** data type: "INTEGER" 4171** collation sequence: "BINARY" 4172** not null: 0 4173** primary key: 1 4174** auto increment: 0 4175** </pre>)^ 4176** 4177** ^(This function may load one or more schemas from database files. If an 4178** error occurs during this process, or if the requested table or column 4179** cannot be found, an [error code] is returned and an error message left 4180** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^ 4181** 4182** ^This API is only available if the library was compiled with the 4183** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined. 4184*/ 4185SQLITE_API int sqlite3_table_column_metadata( 4186 sqlite3 *db, /* Connection handle */ 4187 const char *zDbName, /* Database name or NULL */ 4188 const char *zTableName, /* Table name */ 4189 const char *zColumnName, /* Column name */ 4190 char const **pzDataType, /* OUTPUT: Declared data type */ 4191 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 4192 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 4193 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 4194 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 4195); 4196 4197/* 4198** CAPI3REF: Load An Extension 4199** 4200** ^This interface loads an SQLite extension library from the named file. 4201** 4202** ^The sqlite3_load_extension() interface attempts to load an 4203** SQLite extension library contained in the file zFile. 4204** 4205** ^The entry point is zProc. 4206** ^zProc may be 0, in which case the name of the entry point 4207** defaults to "sqlite3_extension_init". 4208** ^The sqlite3_load_extension() interface returns 4209** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 4210** ^If an error occurs and pzErrMsg is not 0, then the 4211** [sqlite3_load_extension()] interface shall attempt to 4212** fill *pzErrMsg with error message text stored in memory 4213** obtained from [sqlite3_malloc()]. The calling function 4214** should free this memory by calling [sqlite3_free()]. 4215** 4216** ^Extension loading must be enabled using 4217** [sqlite3_enable_load_extension()] prior to calling this API, 4218** otherwise an error will be returned. 4219** 4220** See also the [load_extension() SQL function]. 4221*/ 4222SQLITE_API int sqlite3_load_extension( 4223 sqlite3 *db, /* Load the extension into this database connection */ 4224 const char *zFile, /* Name of the shared library containing extension */ 4225 const char *zProc, /* Entry point. Derived from zFile if 0 */ 4226 char **pzErrMsg /* Put error message here if not 0 */ 4227); 4228 4229/* 4230** CAPI3REF: Enable Or Disable Extension Loading 4231** 4232** ^So as not to open security holes in older applications that are 4233** unprepared to deal with extension loading, and as a means of disabling 4234** extension loading while evaluating user-entered SQL, the following API 4235** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 4236** 4237** ^Extension loading is off by default. See ticket #1863. 4238** ^Call the sqlite3_enable_load_extension() routine with onoff==1 4239** to turn extension loading on and call it with onoff==0 to turn 4240** it back off again. 4241*/ 4242SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 4243 4244/* 4245** CAPI3REF: Automatically Load An Extensions 4246** 4247** ^This API can be invoked at program startup in order to register 4248** one or more statically linked extensions that will be available 4249** to all new [database connections]. 4250** 4251** ^(This routine stores a pointer to the extension entry point 4252** in an array that is obtained from [sqlite3_malloc()]. That memory 4253** is deallocated by [sqlite3_reset_auto_extension()].)^ 4254** 4255** ^This function registers an extension entry point that is 4256** automatically invoked whenever a new [database connection] 4257** is opened using [sqlite3_open()], [sqlite3_open16()], 4258** or [sqlite3_open_v2()]. 4259** ^Duplicate extensions are detected so calling this routine 4260** multiple times with the same extension is harmless. 4261** ^Automatic extensions apply across all threads. 4262*/ 4263SQLITE_API int sqlite3_auto_extension(void (*xEntryPoint)(void)); 4264 4265/* 4266** CAPI3REF: Reset Automatic Extension Loading 4267** 4268** ^(This function disables all previously registered automatic 4269** extensions. It undoes the effect of all prior 4270** [sqlite3_auto_extension()] calls.)^ 4271** 4272** ^This function disables automatic extensions in all threads. 4273*/ 4274SQLITE_API void sqlite3_reset_auto_extension(void); 4275 4276/* 4277** The interface to the virtual-table mechanism is currently considered 4278** to be experimental. The interface might change in incompatible ways. 4279** If this is a problem for you, do not use the interface at this time. 4280** 4281** When the virtual-table mechanism stabilizes, we will declare the 4282** interface fixed, support it indefinitely, and remove this comment. 4283*/ 4284 4285/* 4286** Structures used by the virtual table interface 4287*/ 4288typedef struct sqlite3_vtab sqlite3_vtab; 4289typedef struct sqlite3_index_info sqlite3_index_info; 4290typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 4291typedef struct sqlite3_module sqlite3_module; 4292 4293/* 4294** CAPI3REF: Virtual Table Object 4295** KEYWORDS: sqlite3_module {virtual table module} 4296** 4297** This structure, sometimes called a a "virtual table module", 4298** defines the implementation of a [virtual tables]. 4299** This structure consists mostly of methods for the module. 4300** 4301** ^A virtual table module is created by filling in a persistent 4302** instance of this structure and passing a pointer to that instance 4303** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 4304** ^The registration remains valid until it is replaced by a different 4305** module or until the [database connection] closes. The content 4306** of this structure must not change while it is registered with 4307** any database connection. 4308*/ 4309struct sqlite3_module { 4310 int iVersion; 4311 int (*xCreate)(sqlite3*, void *pAux, 4312 int argc, const char *const*argv, 4313 sqlite3_vtab **ppVTab, char**); 4314 int (*xConnect)(sqlite3*, void *pAux, 4315 int argc, const char *const*argv, 4316 sqlite3_vtab **ppVTab, char**); 4317 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 4318 int (*xDisconnect)(sqlite3_vtab *pVTab); 4319 int (*xDestroy)(sqlite3_vtab *pVTab); 4320 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 4321 int (*xClose)(sqlite3_vtab_cursor*); 4322 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 4323 int argc, sqlite3_value **argv); 4324 int (*xNext)(sqlite3_vtab_cursor*); 4325 int (*xEof)(sqlite3_vtab_cursor*); 4326 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 4327 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 4328 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 4329 int (*xBegin)(sqlite3_vtab *pVTab); 4330 int (*xSync)(sqlite3_vtab *pVTab); 4331 int (*xCommit)(sqlite3_vtab *pVTab); 4332 int (*xRollback)(sqlite3_vtab *pVTab); 4333 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 4334 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 4335 void **ppArg); 4336 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 4337}; 4338 4339/* 4340** CAPI3REF: Virtual Table Indexing Information 4341** KEYWORDS: sqlite3_index_info 4342** 4343** The sqlite3_index_info structure and its substructures is used as part 4344** of the [virtual table] interface to 4345** pass information into and receive the reply from the [xBestIndex] 4346** method of a [virtual table module]. The fields under **Inputs** are the 4347** inputs to xBestIndex and are read-only. xBestIndex inserts its 4348** results into the **Outputs** fields. 4349** 4350** ^(The aConstraint[] array records WHERE clause constraints of the form: 4351** 4352** <blockquote>column OP expr</blockquote> 4353** 4354** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 4355** stored in aConstraint[].op using one of the 4356** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 4357** ^(The index of the column is stored in 4358** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 4359** expr on the right-hand side can be evaluated (and thus the constraint 4360** is usable) and false if it cannot.)^ 4361** 4362** ^The optimizer automatically inverts terms of the form "expr OP column" 4363** and makes other simplifications to the WHERE clause in an attempt to 4364** get as many WHERE clause terms into the form shown above as possible. 4365** ^The aConstraint[] array only reports WHERE clause terms that are 4366** relevant to the particular virtual table being queried. 4367** 4368** ^Information about the ORDER BY clause is stored in aOrderBy[]. 4369** ^Each term of aOrderBy records a column of the ORDER BY clause. 4370** 4371** The [xBestIndex] method must fill aConstraintUsage[] with information 4372** about what parameters to pass to xFilter. ^If argvIndex>0 then 4373** the right-hand side of the corresponding aConstraint[] is evaluated 4374** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 4375** is true, then the constraint is assumed to be fully handled by the 4376** virtual table and is not checked again by SQLite.)^ 4377** 4378** ^The idxNum and idxPtr values are recorded and passed into the 4379** [xFilter] method. 4380** ^[sqlite3_free()] is used to free idxPtr if and only if 4381** needToFreeIdxPtr is true. 4382** 4383** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 4384** the correct order to satisfy the ORDER BY clause so that no separate 4385** sorting step is required. 4386** 4387** ^The estimatedCost value is an estimate of the cost of doing the 4388** particular lookup. A full scan of a table with N entries should have 4389** a cost of N. A binary search of a table of N entries should have a 4390** cost of approximately log(N). 4391*/ 4392struct sqlite3_index_info { 4393 /* Inputs */ 4394 int nConstraint; /* Number of entries in aConstraint */ 4395 struct sqlite3_index_constraint { 4396 int iColumn; /* Column on left-hand side of constraint */ 4397 unsigned char op; /* Constraint operator */ 4398 unsigned char usable; /* True if this constraint is usable */ 4399 int iTermOffset; /* Used internally - xBestIndex should ignore */ 4400 } *aConstraint; /* Table of WHERE clause constraints */ 4401 int nOrderBy; /* Number of terms in the ORDER BY clause */ 4402 struct sqlite3_index_orderby { 4403 int iColumn; /* Column number */ 4404 unsigned char desc; /* True for DESC. False for ASC. */ 4405 } *aOrderBy; /* The ORDER BY clause */ 4406 /* Outputs */ 4407 struct sqlite3_index_constraint_usage { 4408 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 4409 unsigned char omit; /* Do not code a test for this constraint */ 4410 } *aConstraintUsage; 4411 int idxNum; /* Number used to identify the index */ 4412 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 4413 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 4414 int orderByConsumed; /* True if output is already ordered */ 4415 double estimatedCost; /* Estimated cost of using this index */ 4416}; 4417 4418/* 4419** CAPI3REF: Virtual Table Constraint Operator Codes 4420** 4421** These macros defined the allowed values for the 4422** [sqlite3_index_info].aConstraint[].op field. Each value represents 4423** an operator that is part of a constraint term in the wHERE clause of 4424** a query that uses a [virtual table]. 4425*/ 4426#define SQLITE_INDEX_CONSTRAINT_EQ 2 4427#define SQLITE_INDEX_CONSTRAINT_GT 4 4428#define SQLITE_INDEX_CONSTRAINT_LE 8 4429#define SQLITE_INDEX_CONSTRAINT_LT 16 4430#define SQLITE_INDEX_CONSTRAINT_GE 32 4431#define SQLITE_INDEX_CONSTRAINT_MATCH 64 4432 4433/* 4434** CAPI3REF: Register A Virtual Table Implementation 4435** 4436** ^These routines are used to register a new [virtual table module] name. 4437** ^Module names must be registered before 4438** creating a new [virtual table] using the module and before using a 4439** preexisting [virtual table] for the module. 4440** 4441** ^The module name is registered on the [database connection] specified 4442** by the first parameter. ^The name of the module is given by the 4443** second parameter. ^The third parameter is a pointer to 4444** the implementation of the [virtual table module]. ^The fourth 4445** parameter is an arbitrary client data pointer that is passed through 4446** into the [xCreate] and [xConnect] methods of the virtual table module 4447** when a new virtual table is be being created or reinitialized. 4448** 4449** ^The sqlite3_create_module_v2() interface has a fifth parameter which 4450** is a pointer to a destructor for the pClientData. ^SQLite will 4451** invoke the destructor function (if it is not NULL) when SQLite 4452** no longer needs the pClientData pointer. ^The sqlite3_create_module() 4453** interface is equivalent to sqlite3_create_module_v2() with a NULL 4454** destructor. 4455*/ 4456SQLITE_API int sqlite3_create_module( 4457 sqlite3 *db, /* SQLite connection to register module with */ 4458 const char *zName, /* Name of the module */ 4459 const sqlite3_module *p, /* Methods for the module */ 4460 void *pClientData /* Client data for xCreate/xConnect */ 4461); 4462SQLITE_API int sqlite3_create_module_v2( 4463 sqlite3 *db, /* SQLite connection to register module with */ 4464 const char *zName, /* Name of the module */ 4465 const sqlite3_module *p, /* Methods for the module */ 4466 void *pClientData, /* Client data for xCreate/xConnect */ 4467 void(*xDestroy)(void*) /* Module destructor function */ 4468); 4469 4470/* 4471** CAPI3REF: Virtual Table Instance Object 4472** KEYWORDS: sqlite3_vtab 4473** 4474** Every [virtual table module] implementation uses a subclass 4475** of this object to describe a particular instance 4476** of the [virtual table]. Each subclass will 4477** be tailored to the specific needs of the module implementation. 4478** The purpose of this superclass is to define certain fields that are 4479** common to all module implementations. 4480** 4481** ^Virtual tables methods can set an error message by assigning a 4482** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 4483** take care that any prior string is freed by a call to [sqlite3_free()] 4484** prior to assigning a new string to zErrMsg. ^After the error message 4485** is delivered up to the client application, the string will be automatically 4486** freed by sqlite3_free() and the zErrMsg field will be zeroed. 4487*/ 4488struct sqlite3_vtab { 4489 const sqlite3_module *pModule; /* The module for this virtual table */ 4490 int nRef; /* NO LONGER USED */ 4491 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 4492 /* Virtual table implementations will typically add additional fields */ 4493}; 4494 4495/* 4496** CAPI3REF: Virtual Table Cursor Object 4497** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 4498** 4499** Every [virtual table module] implementation uses a subclass of the 4500** following structure to describe cursors that point into the 4501** [virtual table] and are used 4502** to loop through the virtual table. Cursors are created using the 4503** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 4504** by the [sqlite3_module.xClose | xClose] method. Cursors are used 4505** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 4506** of the module. Each module implementation will define 4507** the content of a cursor structure to suit its own needs. 4508** 4509** This superclass exists in order to define fields of the cursor that 4510** are common to all implementations. 4511*/ 4512struct sqlite3_vtab_cursor { 4513 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 4514 /* Virtual table implementations will typically add additional fields */ 4515}; 4516 4517/* 4518** CAPI3REF: Declare The Schema Of A Virtual Table 4519** 4520** ^The [xCreate] and [xConnect] methods of a 4521** [virtual table module] call this interface 4522** to declare the format (the names and datatypes of the columns) of 4523** the virtual tables they implement. 4524*/ 4525SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 4526 4527/* 4528** CAPI3REF: Overload A Function For A Virtual Table 4529** 4530** ^(Virtual tables can provide alternative implementations of functions 4531** using the [xFindFunction] method of the [virtual table module]. 4532** But global versions of those functions 4533** must exist in order to be overloaded.)^ 4534** 4535** ^(This API makes sure a global version of a function with a particular 4536** name and number of parameters exists. If no such function exists 4537** before this API is called, a new function is created.)^ ^The implementation 4538** of the new function always causes an exception to be thrown. So 4539** the new function is not good for anything by itself. Its only 4540** purpose is to be a placeholder function that can be overloaded 4541** by a [virtual table]. 4542*/ 4543SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 4544 4545/* 4546** The interface to the virtual-table mechanism defined above (back up 4547** to a comment remarkably similar to this one) is currently considered 4548** to be experimental. The interface might change in incompatible ways. 4549** If this is a problem for you, do not use the interface at this time. 4550** 4551** When the virtual-table mechanism stabilizes, we will declare the 4552** interface fixed, support it indefinitely, and remove this comment. 4553*/ 4554 4555/* 4556** CAPI3REF: A Handle To An Open BLOB 4557** KEYWORDS: {BLOB handle} {BLOB handles} 4558** 4559** An instance of this object represents an open BLOB on which 4560** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 4561** ^Objects of this type are created by [sqlite3_blob_open()] 4562** and destroyed by [sqlite3_blob_close()]. 4563** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 4564** can be used to read or write small subsections of the BLOB. 4565** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 4566*/ 4567typedef struct sqlite3_blob sqlite3_blob; 4568 4569/* 4570** CAPI3REF: Open A BLOB For Incremental I/O 4571** 4572** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 4573** in row iRow, column zColumn, table zTable in database zDb; 4574** in other words, the same BLOB that would be selected by: 4575** 4576** <pre> 4577** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 4578** </pre>)^ 4579** 4580** ^If the flags parameter is non-zero, then the BLOB is opened for read 4581** and write access. ^If it is zero, the BLOB is opened for read access. 4582** ^It is not possible to open a column that is part of an index or primary 4583** key for writing. ^If [foreign key constraints] are enabled, it is 4584** not possible to open a column that is part of a [child key] for writing. 4585** 4586** ^Note that the database name is not the filename that contains 4587** the database but rather the symbolic name of the database that 4588** appears after the AS keyword when the database is connected using [ATTACH]. 4589** ^For the main database file, the database name is "main". 4590** ^For TEMP tables, the database name is "temp". 4591** 4592** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written 4593** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set 4594** to be a null pointer.)^ 4595** ^This function sets the [database connection] error code and message 4596** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related 4597** functions. ^Note that the *ppBlob variable is always initialized in a 4598** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob 4599** regardless of the success or failure of this routine. 4600** 4601** ^(If the row that a BLOB handle points to is modified by an 4602** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 4603** then the BLOB handle is marked as "expired". 4604** This is true if any column of the row is changed, even a column 4605** other than the one the BLOB handle is open on.)^ 4606** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 4607** a expired BLOB handle fail with an return code of [SQLITE_ABORT]. 4608** ^(Changes written into a BLOB prior to the BLOB expiring are not 4609** rolled back by the expiration of the BLOB. Such changes will eventually 4610** commit if the transaction continues to completion.)^ 4611** 4612** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 4613** the opened blob. ^The size of a blob may not be changed by this 4614** interface. Use the [UPDATE] SQL command to change the size of a 4615** blob. 4616** 4617** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 4618** and the built-in [zeroblob] SQL function can be used, if desired, 4619** to create an empty, zero-filled blob in which to read or write using 4620** this interface. 4621** 4622** To avoid a resource leak, every open [BLOB handle] should eventually 4623** be released by a call to [sqlite3_blob_close()]. 4624*/ 4625SQLITE_API int sqlite3_blob_open( 4626 sqlite3*, 4627 const char *zDb, 4628 const char *zTable, 4629 const char *zColumn, 4630 sqlite3_int64 iRow, 4631 int flags, 4632 sqlite3_blob **ppBlob 4633); 4634 4635/* 4636** CAPI3REF: Close A BLOB Handle 4637** 4638** ^Closes an open [BLOB handle]. 4639** 4640** ^Closing a BLOB shall cause the current transaction to commit 4641** if there are no other BLOBs, no pending prepared statements, and the 4642** database connection is in [autocommit mode]. 4643** ^If any writes were made to the BLOB, they might be held in cache 4644** until the close operation if they will fit. 4645** 4646** ^(Closing the BLOB often forces the changes 4647** out to disk and so if any I/O errors occur, they will likely occur 4648** at the time when the BLOB is closed. Any errors that occur during 4649** closing are reported as a non-zero return value.)^ 4650** 4651** ^(The BLOB is closed unconditionally. Even if this routine returns 4652** an error code, the BLOB is still closed.)^ 4653** 4654** ^Calling this routine with a null pointer (such as would be returned 4655** by a failed call to [sqlite3_blob_open()]) is a harmless no-op. 4656*/ 4657SQLITE_API int sqlite3_blob_close(sqlite3_blob *); 4658 4659/* 4660** CAPI3REF: Return The Size Of An Open BLOB 4661** 4662** ^Returns the size in bytes of the BLOB accessible via the 4663** successfully opened [BLOB handle] in its only argument. ^The 4664** incremental blob I/O routines can only read or overwriting existing 4665** blob content; they cannot change the size of a blob. 4666** 4667** This routine only works on a [BLOB handle] which has been created 4668** by a prior successful call to [sqlite3_blob_open()] and which has not 4669** been closed by [sqlite3_blob_close()]. Passing any other pointer in 4670** to this routine results in undefined and probably undesirable behavior. 4671*/ 4672SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *); 4673 4674/* 4675** CAPI3REF: Read Data From A BLOB Incrementally 4676** 4677** ^(This function is used to read data from an open [BLOB handle] into a 4678** caller-supplied buffer. N bytes of data are copied into buffer Z 4679** from the open BLOB, starting at offset iOffset.)^ 4680** 4681** ^If offset iOffset is less than N bytes from the end of the BLOB, 4682** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 4683** less than zero, [SQLITE_ERROR] is returned and no data is read. 4684** ^The size of the blob (and hence the maximum value of N+iOffset) 4685** can be determined using the [sqlite3_blob_bytes()] interface. 4686** 4687** ^An attempt to read from an expired [BLOB handle] fails with an 4688** error code of [SQLITE_ABORT]. 4689** 4690** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 4691** Otherwise, an [error code] or an [extended error code] is returned.)^ 4692** 4693** This routine only works on a [BLOB handle] which has been created 4694** by a prior successful call to [sqlite3_blob_open()] and which has not 4695** been closed by [sqlite3_blob_close()]. Passing any other pointer in 4696** to this routine results in undefined and probably undesirable behavior. 4697** 4698** See also: [sqlite3_blob_write()]. 4699*/ 4700SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 4701 4702/* 4703** CAPI3REF: Write Data Into A BLOB Incrementally 4704** 4705** ^This function is used to write data into an open [BLOB handle] from a 4706** caller-supplied buffer. ^N bytes of data are copied from the buffer Z 4707** into the open BLOB, starting at offset iOffset. 4708** 4709** ^If the [BLOB handle] passed as the first argument was not opened for 4710** writing (the flags parameter to [sqlite3_blob_open()] was zero), 4711** this function returns [SQLITE_READONLY]. 4712** 4713** ^This function may only modify the contents of the BLOB; it is 4714** not possible to increase the size of a BLOB using this API. 4715** ^If offset iOffset is less than N bytes from the end of the BLOB, 4716** [SQLITE_ERROR] is returned and no data is written. ^If N is 4717** less than zero [SQLITE_ERROR] is returned and no data is written. 4718** The size of the BLOB (and hence the maximum value of N+iOffset) 4719** can be determined using the [sqlite3_blob_bytes()] interface. 4720** 4721** ^An attempt to write to an expired [BLOB handle] fails with an 4722** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 4723** before the [BLOB handle] expired are not rolled back by the 4724** expiration of the handle, though of course those changes might 4725** have been overwritten by the statement that expired the BLOB handle 4726** or by other independent statements. 4727** 4728** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 4729** Otherwise, an [error code] or an [extended error code] is returned.)^ 4730** 4731** This routine only works on a [BLOB handle] which has been created 4732** by a prior successful call to [sqlite3_blob_open()] and which has not 4733** been closed by [sqlite3_blob_close()]. Passing any other pointer in 4734** to this routine results in undefined and probably undesirable behavior. 4735** 4736** See also: [sqlite3_blob_read()]. 4737*/ 4738SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 4739 4740/* 4741** CAPI3REF: Virtual File System Objects 4742** 4743** A virtual filesystem (VFS) is an [sqlite3_vfs] object 4744** that SQLite uses to interact 4745** with the underlying operating system. Most SQLite builds come with a 4746** single default VFS that is appropriate for the host computer. 4747** New VFSes can be registered and existing VFSes can be unregistered. 4748** The following interfaces are provided. 4749** 4750** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 4751** ^Names are case sensitive. 4752** ^Names are zero-terminated UTF-8 strings. 4753** ^If there is no match, a NULL pointer is returned. 4754** ^If zVfsName is NULL then the default VFS is returned. 4755** 4756** ^New VFSes are registered with sqlite3_vfs_register(). 4757** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 4758** ^The same VFS can be registered multiple times without injury. 4759** ^To make an existing VFS into the default VFS, register it again 4760** with the makeDflt flag set. If two different VFSes with the 4761** same name are registered, the behavior is undefined. If a 4762** VFS is registered with a name that is NULL or an empty string, 4763** then the behavior is undefined. 4764** 4765** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 4766** ^(If the default VFS is unregistered, another VFS is chosen as 4767** the default. The choice for the new VFS is arbitrary.)^ 4768*/ 4769SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 4770SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 4771SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*); 4772 4773/* 4774** CAPI3REF: Mutexes 4775** 4776** The SQLite core uses these routines for thread 4777** synchronization. Though they are intended for internal 4778** use by SQLite, code that links against SQLite is 4779** permitted to use any of these routines. 4780** 4781** The SQLite source code contains multiple implementations 4782** of these mutex routines. An appropriate implementation 4783** is selected automatically at compile-time. ^(The following 4784** implementations are available in the SQLite core: 4785** 4786** <ul> 4787** <li> SQLITE_MUTEX_OS2 4788** <li> SQLITE_MUTEX_PTHREAD 4789** <li> SQLITE_MUTEX_W32 4790** <li> SQLITE_MUTEX_NOOP 4791** </ul>)^ 4792** 4793** ^The SQLITE_MUTEX_NOOP implementation is a set of routines 4794** that does no real locking and is appropriate for use in 4795** a single-threaded application. ^The SQLITE_MUTEX_OS2, 4796** SQLITE_MUTEX_PTHREAD, and SQLITE_MUTEX_W32 implementations 4797** are appropriate for use on OS/2, Unix, and Windows. 4798** 4799** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 4800** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 4801** implementation is included with the library. In this case the 4802** application must supply a custom mutex implementation using the 4803** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 4804** before calling sqlite3_initialize() or any other public sqlite3_ 4805** function that calls sqlite3_initialize().)^ 4806** 4807** ^The sqlite3_mutex_alloc() routine allocates a new 4808** mutex and returns a pointer to it. ^If it returns NULL 4809** that means that a mutex could not be allocated. ^SQLite 4810** will unwind its stack and return an error. ^(The argument 4811** to sqlite3_mutex_alloc() is one of these integer constants: 4812** 4813** <ul> 4814** <li> SQLITE_MUTEX_FAST 4815** <li> SQLITE_MUTEX_RECURSIVE 4816** <li> SQLITE_MUTEX_STATIC_MASTER 4817** <li> SQLITE_MUTEX_STATIC_MEM 4818** <li> SQLITE_MUTEX_STATIC_MEM2 4819** <li> SQLITE_MUTEX_STATIC_PRNG 4820** <li> SQLITE_MUTEX_STATIC_LRU 4821** <li> SQLITE_MUTEX_STATIC_LRU2 4822** </ul>)^ 4823** 4824** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 4825** cause sqlite3_mutex_alloc() to create 4826** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 4827** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 4828** The mutex implementation does not need to make a distinction 4829** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 4830** not want to. ^SQLite will only request a recursive mutex in 4831** cases where it really needs one. ^If a faster non-recursive mutex 4832** implementation is available on the host platform, the mutex subsystem 4833** might return such a mutex in response to SQLITE_MUTEX_FAST. 4834** 4835** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 4836** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 4837** a pointer to a static preexisting mutex. ^Six static mutexes are 4838** used by the current version of SQLite. Future versions of SQLite 4839** may add additional static mutexes. Static mutexes are for internal 4840** use by SQLite only. Applications that use SQLite mutexes should 4841** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 4842** SQLITE_MUTEX_RECURSIVE. 4843** 4844** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 4845** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 4846** returns a different mutex on every call. ^But for the static 4847** mutex types, the same mutex is returned on every call that has 4848** the same type number. 4849** 4850** ^The sqlite3_mutex_free() routine deallocates a previously 4851** allocated dynamic mutex. ^SQLite is careful to deallocate every 4852** dynamic mutex that it allocates. The dynamic mutexes must not be in 4853** use when they are deallocated. Attempting to deallocate a static 4854** mutex results in undefined behavior. ^SQLite never deallocates 4855** a static mutex. 4856** 4857** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 4858** to enter a mutex. ^If another thread is already within the mutex, 4859** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 4860** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 4861** upon successful entry. ^(Mutexes created using 4862** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 4863** In such cases the, 4864** mutex must be exited an equal number of times before another thread 4865** can enter.)^ ^(If the same thread tries to enter any other 4866** kind of mutex more than once, the behavior is undefined. 4867** SQLite will never exhibit 4868** such behavior in its own use of mutexes.)^ 4869** 4870** ^(Some systems (for example, Windows 95) do not support the operation 4871** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 4872** will always return SQLITE_BUSY. The SQLite core only ever uses 4873** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^ 4874** 4875** ^The sqlite3_mutex_leave() routine exits a mutex that was 4876** previously entered by the same thread. ^(The behavior 4877** is undefined if the mutex is not currently entered by the 4878** calling thread or is not currently allocated. SQLite will 4879** never do either.)^ 4880** 4881** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 4882** sqlite3_mutex_leave() is a NULL pointer, then all three routines 4883** behave as no-ops. 4884** 4885** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 4886*/ 4887SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int); 4888SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*); 4889SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*); 4890SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*); 4891SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*); 4892 4893/* 4894** CAPI3REF: Mutex Methods Object 4895** 4896** An instance of this structure defines the low-level routines 4897** used to allocate and use mutexes. 4898** 4899** Usually, the default mutex implementations provided by SQLite are 4900** sufficient, however the user has the option of substituting a custom 4901** implementation for specialized deployments or systems for which SQLite 4902** does not provide a suitable implementation. In this case, the user 4903** creates and populates an instance of this structure to pass 4904** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 4905** Additionally, an instance of this structure can be used as an 4906** output variable when querying the system for the current mutex 4907** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 4908** 4909** ^The xMutexInit method defined by this structure is invoked as 4910** part of system initialization by the sqlite3_initialize() function. 4911** ^The xMutexInit routine is calle by SQLite exactly once for each 4912** effective call to [sqlite3_initialize()]. 4913** 4914** ^The xMutexEnd method defined by this structure is invoked as 4915** part of system shutdown by the sqlite3_shutdown() function. The 4916** implementation of this method is expected to release all outstanding 4917** resources obtained by the mutex methods implementation, especially 4918** those obtained by the xMutexInit method. ^The xMutexEnd() 4919** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 4920** 4921** ^(The remaining seven methods defined by this structure (xMutexAlloc, 4922** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 4923** xMutexNotheld) implement the following interfaces (respectively): 4924** 4925** <ul> 4926** <li> [sqlite3_mutex_alloc()] </li> 4927** <li> [sqlite3_mutex_free()] </li> 4928** <li> [sqlite3_mutex_enter()] </li> 4929** <li> [sqlite3_mutex_try()] </li> 4930** <li> [sqlite3_mutex_leave()] </li> 4931** <li> [sqlite3_mutex_held()] </li> 4932** <li> [sqlite3_mutex_notheld()] </li> 4933** </ul>)^ 4934** 4935** The only difference is that the public sqlite3_XXX functions enumerated 4936** above silently ignore any invocations that pass a NULL pointer instead 4937** of a valid mutex handle. The implementations of the methods defined 4938** by this structure are not required to handle this case, the results 4939** of passing a NULL pointer instead of a valid mutex handle are undefined 4940** (i.e. it is acceptable to provide an implementation that segfaults if 4941** it is passed a NULL pointer). 4942** 4943** The xMutexInit() method must be threadsafe. ^It must be harmless to 4944** invoke xMutexInit() multiple times within the same process and without 4945** intervening calls to xMutexEnd(). Second and subsequent calls to 4946** xMutexInit() must be no-ops. 4947** 4948** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 4949** and its associates). ^Similarly, xMutexAlloc() must not use SQLite memory 4950** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 4951** memory allocation for a fast or recursive mutex. 4952** 4953** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 4954** called, but only if the prior call to xMutexInit returned SQLITE_OK. 4955** If xMutexInit fails in any way, it is expected to clean up after itself 4956** prior to returning. 4957*/ 4958typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 4959struct sqlite3_mutex_methods { 4960 int (*xMutexInit)(void); 4961 int (*xMutexEnd)(void); 4962 sqlite3_mutex *(*xMutexAlloc)(int); 4963 void (*xMutexFree)(sqlite3_mutex *); 4964 void (*xMutexEnter)(sqlite3_mutex *); 4965 int (*xMutexTry)(sqlite3_mutex *); 4966 void (*xMutexLeave)(sqlite3_mutex *); 4967 int (*xMutexHeld)(sqlite3_mutex *); 4968 int (*xMutexNotheld)(sqlite3_mutex *); 4969}; 4970 4971/* 4972** CAPI3REF: Mutex Verification Routines 4973** 4974** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 4975** are intended for use inside assert() statements. ^The SQLite core 4976** never uses these routines except inside an assert() and applications 4977** are advised to follow the lead of the core. ^The SQLite core only 4978** provides implementations for these routines when it is compiled 4979** with the SQLITE_DEBUG flag. ^External mutex implementations 4980** are only required to provide these routines if SQLITE_DEBUG is 4981** defined and if NDEBUG is not defined. 4982** 4983** ^These routines should return true if the mutex in their argument 4984** is held or not held, respectively, by the calling thread. 4985** 4986** ^The implementation is not required to provided versions of these 4987** routines that actually work. If the implementation does not provide working 4988** versions of these routines, it should at least provide stubs that always 4989** return true so that one does not get spurious assertion failures. 4990** 4991** ^If the argument to sqlite3_mutex_held() is a NULL pointer then 4992** the routine should return 1. This seems counter-intuitive since 4993** clearly the mutex cannot be held if it does not exist. But the 4994** the reason the mutex does not exist is because the build is not 4995** using mutexes. And we do not want the assert() containing the 4996** call to sqlite3_mutex_held() to fail, so a non-zero return is 4997** the appropriate thing to do. ^The sqlite3_mutex_notheld() 4998** interface should also return 1 when given a NULL pointer. 4999*/ 5000#ifndef NDEBUG 5001SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*); 5002SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*); 5003#endif 5004 5005/* 5006** CAPI3REF: Mutex Types 5007** 5008** The [sqlite3_mutex_alloc()] interface takes a single argument 5009** which is one of these integer constants. 5010** 5011** The set of static mutexes may change from one SQLite release to the 5012** next. Applications that override the built-in mutex logic must be 5013** prepared to accommodate additional static mutexes. 5014*/ 5015#define SQLITE_MUTEX_FAST 0 5016#define SQLITE_MUTEX_RECURSIVE 1 5017#define SQLITE_MUTEX_STATIC_MASTER 2 5018#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 5019#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 5020#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 5021#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ 5022#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 5023#define SQLITE_MUTEX_STATIC_LRU2 7 /* lru page list */ 5024 5025/* 5026** CAPI3REF: Retrieve the mutex for a database connection 5027** 5028** ^This interface returns a pointer the [sqlite3_mutex] object that 5029** serializes access to the [database connection] given in the argument 5030** when the [threading mode] is Serialized. 5031** ^If the [threading mode] is Single-thread or Multi-thread then this 5032** routine returns a NULL pointer. 5033*/ 5034SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 5035 5036/* 5037** CAPI3REF: Low-Level Control Of Database Files 5038** 5039** ^The [sqlite3_file_control()] interface makes a direct call to the 5040** xFileControl method for the [sqlite3_io_methods] object associated 5041** with a particular database identified by the second argument. ^The 5042** name of the database "main" for the main database or "temp" for the 5043** TEMP database, or the name that appears after the AS keyword for 5044** databases that are added using the [ATTACH] SQL command. 5045** ^A NULL pointer can be used in place of "main" to refer to the 5046** main database file. 5047** ^The third and fourth parameters to this routine 5048** are passed directly through to the second and third parameters of 5049** the xFileControl method. ^The return value of the xFileControl 5050** method becomes the return value of this routine. 5051** 5052** ^If the second parameter (zDbName) does not match the name of any 5053** open database file, then SQLITE_ERROR is returned. ^This error 5054** code is not remembered and will not be recalled by [sqlite3_errcode()] 5055** or [sqlite3_errmsg()]. The underlying xFileControl method might 5056** also return SQLITE_ERROR. There is no way to distinguish between 5057** an incorrect zDbName and an SQLITE_ERROR return from the underlying 5058** xFileControl method. 5059** 5060** See also: [SQLITE_FCNTL_LOCKSTATE] 5061*/ 5062SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 5063 5064/* 5065** CAPI3REF: Testing Interface 5066** 5067** ^The sqlite3_test_control() interface is used to read out internal 5068** state of SQLite and to inject faults into SQLite for testing 5069** purposes. ^The first parameter is an operation code that determines 5070** the number, meaning, and operation of all subsequent parameters. 5071** 5072** This interface is not for use by applications. It exists solely 5073** for verifying the correct operation of the SQLite library. Depending 5074** on how the SQLite library is compiled, this interface might not exist. 5075** 5076** The details of the operation codes, their meanings, the parameters 5077** they take, and what they do are all subject to change without notice. 5078** Unlike most of the SQLite API, this function is not guaranteed to 5079** operate consistently from one release to the next. 5080*/ 5081SQLITE_API int sqlite3_test_control(int op, ...); 5082 5083/* 5084** CAPI3REF: Testing Interface Operation Codes 5085** 5086** These constants are the valid operation code parameters used 5087** as the first argument to [sqlite3_test_control()]. 5088** 5089** These parameters and their meanings are subject to change 5090** without notice. These values are for testing purposes only. 5091** Applications should not use any of these parameters or the 5092** [sqlite3_test_control()] interface. 5093*/ 5094#define SQLITE_TESTCTRL_FIRST 5 5095#define SQLITE_TESTCTRL_PRNG_SAVE 5 5096#define SQLITE_TESTCTRL_PRNG_RESTORE 6 5097#define SQLITE_TESTCTRL_PRNG_RESET 7 5098#define SQLITE_TESTCTRL_BITVEC_TEST 8 5099#define SQLITE_TESTCTRL_FAULT_INSTALL 9 5100#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 5101#define SQLITE_TESTCTRL_PENDING_BYTE 11 5102#define SQLITE_TESTCTRL_ASSERT 12 5103#define SQLITE_TESTCTRL_ALWAYS 13 5104#define SQLITE_TESTCTRL_RESERVE 14 5105#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 5106#define SQLITE_TESTCTRL_ISKEYWORD 16 5107#define SQLITE_TESTCTRL_PGHDRSZ 17 5108#define SQLITE_TESTCTRL_LAST 17 5109 5110/* 5111** CAPI3REF: SQLite Runtime Status 5112** 5113** ^This interface is used to retrieve runtime status information 5114** about the performance of SQLite, and optionally to reset various 5115** highwater marks. ^The first argument is an integer code for 5116** the specific parameter to measure. ^(Recognized integer codes 5117** are of the form [SQLITE_STATUS_MEMORY_USED | SQLITE_STATUS_...].)^ 5118** ^The current value of the parameter is returned into *pCurrent. 5119** ^The highest recorded value is returned in *pHighwater. ^If the 5120** resetFlag is true, then the highest record value is reset after 5121** *pHighwater is written. ^(Some parameters do not record the highest 5122** value. For those parameters 5123** nothing is written into *pHighwater and the resetFlag is ignored.)^ 5124** ^(Other parameters record only the highwater mark and not the current 5125** value. For these latter parameters nothing is written into *pCurrent.)^ 5126** 5127** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 5128** non-zero [error code] on failure. 5129** 5130** This routine is threadsafe but is not atomic. This routine can be 5131** called while other threads are running the same or different SQLite 5132** interfaces. However the values returned in *pCurrent and 5133** *pHighwater reflect the status of SQLite at different points in time 5134** and it is possible that another thread might change the parameter 5135** in between the times when *pCurrent and *pHighwater are written. 5136** 5137** See also: [sqlite3_db_status()] 5138*/ 5139SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 5140 5141 5142/* 5143** CAPI3REF: Status Parameters 5144** 5145** These integer constants designate various run-time status parameters 5146** that can be returned by [sqlite3_status()]. 5147** 5148** <dl> 5149** ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 5150** <dd>This parameter is the current amount of memory checked out 5151** using [sqlite3_malloc()], either directly or indirectly. The 5152** figure includes calls made to [sqlite3_malloc()] by the application 5153** and internal memory usage by the SQLite library. Scratch memory 5154** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 5155** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 5156** this parameter. The amount returned is the sum of the allocation 5157** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 5158** 5159** ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 5160** <dd>This parameter records the largest memory allocation request 5161** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 5162** internal equivalents). Only the value returned in the 5163** *pHighwater parameter to [sqlite3_status()] is of interest. 5164** The value written into the *pCurrent parameter is undefined.</dd>)^ 5165** 5166** ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 5167** <dd>This parameter records the number of separate memory allocations.</dd>)^ 5168** 5169** ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 5170** <dd>This parameter returns the number of pages used out of the 5171** [pagecache memory allocator] that was configured using 5172** [SQLITE_CONFIG_PAGECACHE]. The 5173** value returned is in pages, not in bytes.</dd>)^ 5174** 5175** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 5176** <dd>This parameter returns the number of bytes of page cache 5177** allocation which could not be statisfied by the [SQLITE_CONFIG_PAGECACHE] 5178** buffer and where forced to overflow to [sqlite3_malloc()]. The 5179** returned value includes allocations that overflowed because they 5180** where too large (they were larger than the "sz" parameter to 5181** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 5182** no space was left in the page cache.</dd>)^ 5183** 5184** ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 5185** <dd>This parameter records the largest memory allocation request 5186** handed to [pagecache memory allocator]. Only the value returned in the 5187** *pHighwater parameter to [sqlite3_status()] is of interest. 5188** The value written into the *pCurrent parameter is undefined.</dd>)^ 5189** 5190** ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt> 5191** <dd>This parameter returns the number of allocations used out of the 5192** [scratch memory allocator] configured using 5193** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 5194** in bytes. Since a single thread may only have one scratch allocation 5195** outstanding at time, this parameter also reports the number of threads 5196** using scratch memory at the same time.</dd>)^ 5197** 5198** ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 5199** <dd>This parameter returns the number of bytes of scratch memory 5200** allocation which could not be statisfied by the [SQLITE_CONFIG_SCRATCH] 5201** buffer and where forced to overflow to [sqlite3_malloc()]. The values 5202** returned include overflows because the requested allocation was too 5203** larger (that is, because the requested allocation was larger than the 5204** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 5205** slots were available. 5206** </dd>)^ 5207** 5208** ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 5209** <dd>This parameter records the largest memory allocation request 5210** handed to [scratch memory allocator]. Only the value returned in the 5211** *pHighwater parameter to [sqlite3_status()] is of interest. 5212** The value written into the *pCurrent parameter is undefined.</dd>)^ 5213** 5214** ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 5215** <dd>This parameter records the deepest parser stack. It is only 5216** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 5217** </dl> 5218** 5219** New status parameters may be added from time to time. 5220*/ 5221#define SQLITE_STATUS_MEMORY_USED 0 5222#define SQLITE_STATUS_PAGECACHE_USED 1 5223#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 5224#define SQLITE_STATUS_SCRATCH_USED 3 5225#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 5226#define SQLITE_STATUS_MALLOC_SIZE 5 5227#define SQLITE_STATUS_PARSER_STACK 6 5228#define SQLITE_STATUS_PAGECACHE_SIZE 7 5229#define SQLITE_STATUS_SCRATCH_SIZE 8 5230#define SQLITE_STATUS_MALLOC_COUNT 9 5231 5232/* 5233** CAPI3REF: Database Connection Status 5234** 5235** ^This interface is used to retrieve runtime status information 5236** about a single [database connection]. ^The first argument is the 5237** database connection object to be interrogated. ^The second argument 5238** is an integer constant, taken from the set of 5239** [SQLITE_DBSTATUS_LOOKASIDE_USED | SQLITE_DBSTATUS_*] macros, that 5240** determines the parameter to interrogate. The set of 5241** [SQLITE_DBSTATUS_LOOKASIDE_USED | SQLITE_DBSTATUS_*] macros is likely 5242** to grow in future releases of SQLite. 5243** 5244** ^The current value of the requested parameter is written into *pCur 5245** and the highest instantaneous value is written into *pHiwtr. ^If 5246** the resetFlg is true, then the highest instantaneous value is 5247** reset back down to the current value. 5248** 5249** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 5250*/ 5251SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 5252 5253/* 5254** CAPI3REF: Status Parameters for database connections 5255** 5256** These constants are the available integer "verbs" that can be passed as 5257** the second argument to the [sqlite3_db_status()] interface. 5258** 5259** New verbs may be added in future releases of SQLite. Existing verbs 5260** might be discontinued. Applications should check the return code from 5261** [sqlite3_db_status()] to make sure that the call worked. 5262** The [sqlite3_db_status()] interface will return a non-zero error code 5263** if a discontinued or unsupported verb is invoked. 5264** 5265** <dl> 5266** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 5267** <dd>This parameter returns the number of lookaside memory slots currently 5268** checked out.</dd>)^ 5269** 5270** ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 5271** <dd>This parameter returns the approximate number of of bytes of heap 5272** memory used by all pager caches associated with the database connection.)^ 5273** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 5274** 5275** ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 5276** <dd>This parameter returns the approximate number of of bytes of heap 5277** memory used to store the schema for all databases associated 5278** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 5279** ^The full amount of memory used by the schemas is reported, even if the 5280** schema memory is shared with other database connections due to 5281** [shared cache mode] being enabled. 5282** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 5283** 5284** ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 5285** <dd>This parameter returns the approximate number of of bytes of heap 5286** and lookaside memory used by all prepared statements associated with 5287** the database connection.)^ 5288** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 5289** </dd> 5290** </dl> 5291*/ 5292#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 5293#define SQLITE_DBSTATUS_CACHE_USED 1 5294#define SQLITE_DBSTATUS_SCHEMA_USED 2 5295#define SQLITE_DBSTATUS_STMT_USED 3 5296#define SQLITE_DBSTATUS_MAX 3 /* Largest defined DBSTATUS */ 5297 5298 5299/* 5300** CAPI3REF: Prepared Statement Status 5301** 5302** ^(Each prepared statement maintains various 5303** [SQLITE_STMTSTATUS_SORT | counters] that measure the number 5304** of times it has performed specific operations.)^ These counters can 5305** be used to monitor the performance characteristics of the prepared 5306** statements. For example, if the number of table steps greatly exceeds 5307** the number of table searches or result rows, that would tend to indicate 5308** that the prepared statement is using a full table scan rather than 5309** an index. 5310** 5311** ^(This interface is used to retrieve and reset counter values from 5312** a [prepared statement]. The first argument is the prepared statement 5313** object to be interrogated. The second argument 5314** is an integer code for a specific [SQLITE_STMTSTATUS_SORT | counter] 5315** to be interrogated.)^ 5316** ^The current value of the requested counter is returned. 5317** ^If the resetFlg is true, then the counter is reset to zero after this 5318** interface call returns. 5319** 5320** See also: [sqlite3_status()] and [sqlite3_db_status()]. 5321*/ 5322SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 5323 5324/* 5325** CAPI3REF: Status Parameters for prepared statements 5326** 5327** These preprocessor macros define integer codes that name counter 5328** values associated with the [sqlite3_stmt_status()] interface. 5329** The meanings of the various counters are as follows: 5330** 5331** <dl> 5332** <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 5333** <dd>^This is the number of times that SQLite has stepped forward in 5334** a table as part of a full table scan. Large numbers for this counter 5335** may indicate opportunities for performance improvement through 5336** careful use of indices.</dd> 5337** 5338** <dt>SQLITE_STMTSTATUS_SORT</dt> 5339** <dd>^This is the number of sort operations that have occurred. 5340** A non-zero value in this counter may indicate an opportunity to 5341** improvement performance through careful use of indices.</dd> 5342** 5343** <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 5344** <dd>^This is the number of rows inserted into transient indices that 5345** were created automatically in order to help joins run faster. 5346** A non-zero value in this counter may indicate an opportunity to 5347** improvement performance by adding permanent indices that do not 5348** need to be reinitialized each time the statement is run.</dd> 5349** 5350** </dl> 5351*/ 5352#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 5353#define SQLITE_STMTSTATUS_SORT 2 5354#define SQLITE_STMTSTATUS_AUTOINDEX 3 5355 5356/* 5357** CAPI3REF: Custom Page Cache Object 5358** 5359** The sqlite3_pcache type is opaque. It is implemented by 5360** the pluggable module. The SQLite core has no knowledge of 5361** its size or internal structure and never deals with the 5362** sqlite3_pcache object except by holding and passing pointers 5363** to the object. 5364** 5365** See [sqlite3_pcache_methods] for additional information. 5366*/ 5367typedef struct sqlite3_pcache sqlite3_pcache; 5368 5369/* 5370** CAPI3REF: Application Defined Page Cache. 5371** KEYWORDS: {page cache} 5372** 5373** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE], ...) interface can 5374** register an alternative page cache implementation by passing in an 5375** instance of the sqlite3_pcache_methods structure.)^ The majority of the 5376** heap memory used by SQLite is used by the page cache to cache data read 5377** from, or ready to be written to, the database file. By implementing a 5378** custom page cache using this API, an application can control more 5379** precisely the amount of memory consumed by SQLite, the way in which 5380** that memory is allocated and released, and the policies used to 5381** determine exactly which parts of a database file are cached and for 5382** how long. 5383** 5384** ^(The contents of the sqlite3_pcache_methods structure are copied to an 5385** internal buffer by SQLite within the call to [sqlite3_config]. Hence 5386** the application may discard the parameter after the call to 5387** [sqlite3_config()] returns.)^ 5388** 5389** ^The xInit() method is called once for each call to [sqlite3_initialize()] 5390** (usually only once during the lifetime of the process). ^(The xInit() 5391** method is passed a copy of the sqlite3_pcache_methods.pArg value.)^ 5392** ^The xInit() method can set up up global structures and/or any mutexes 5393** required by the custom page cache implementation. 5394** 5395** ^The xShutdown() method is called from within [sqlite3_shutdown()], 5396** if the application invokes this API. It can be used to clean up 5397** any outstanding resources before process shutdown, if required. 5398** 5399** ^SQLite holds a [SQLITE_MUTEX_RECURSIVE] mutex when it invokes 5400** the xInit method, so the xInit method need not be threadsafe. ^The 5401** xShutdown method is only called from [sqlite3_shutdown()] so it does 5402** not need to be threadsafe either. All other methods must be threadsafe 5403** in multithreaded applications. 5404** 5405** ^SQLite will never invoke xInit() more than once without an intervening 5406** call to xShutdown(). 5407** 5408** ^The xCreate() method is used to construct a new cache instance. SQLite 5409** will typically create one cache instance for each open database file, 5410** though this is not guaranteed. ^The 5411** first parameter, szPage, is the size in bytes of the pages that must 5412** be allocated by the cache. ^szPage will not be a power of two. ^szPage 5413** will the page size of the database file that is to be cached plus an 5414** increment (here called "R") of about 100 or 200. ^SQLite will use the 5415** extra R bytes on each page to store metadata about the underlying 5416** database page on disk. The value of R depends 5417** on the SQLite version, the target platform, and how SQLite was compiled. 5418** ^R is constant for a particular build of SQLite. ^The second argument to 5419** xCreate(), bPurgeable, is true if the cache being created will 5420** be used to cache database pages of a file stored on disk, or 5421** false if it is used for an in-memory database. ^The cache implementation 5422** does not have to do anything special based with the value of bPurgeable; 5423** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 5424** never invoke xUnpin() except to deliberately delete a page. 5425** ^In other words, a cache created with bPurgeable set to false will 5426** never contain any unpinned pages. 5427** 5428** ^(The xCachesize() method may be called at any time by SQLite to set the 5429** suggested maximum cache-size (number of pages stored by) the cache 5430** instance passed as the first argument. This is the value configured using 5431** the SQLite "[PRAGMA cache_size]" command.)^ ^As with the bPurgeable 5432** parameter, the implementation is not required to do anything with this 5433** value; it is advisory only. 5434** 5435** ^The xPagecount() method should return the number of pages currently 5436** stored in the cache. 5437** 5438** ^The xFetch() method is used to fetch a page and return a pointer to it. 5439** ^A 'page', in this context, is a buffer of szPage bytes aligned at an 5440** 8-byte boundary. ^The page to be fetched is determined by the key. ^The 5441** mimimum key value is 1. After it has been retrieved using xFetch, the page 5442** is considered to be "pinned". 5443** 5444** ^If the requested page is already in the page cache, then the page cache 5445** implementation must return a pointer to the page buffer with its content 5446** intact. ^(If the requested page is not already in the cache, then the 5447** behavior of the cache implementation is determined by the value of the 5448** createFlag parameter passed to xFetch, according to the following table: 5449** 5450** <table border=1 width=85% align=center> 5451** <tr><th> createFlag <th> Behaviour when page is not already in cache 5452** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 5453** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 5454** Otherwise return NULL. 5455** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 5456** NULL if allocating a new page is effectively impossible. 5457** </table>)^ 5458** 5459** SQLite will normally invoke xFetch() with a createFlag of 0 or 1. If 5460** a call to xFetch() with createFlag==1 returns NULL, then SQLite will 5461** attempt to unpin one or more cache pages by spilling the content of 5462** pinned pages to disk and synching the operating system disk cache. After 5463** attempting to unpin pages, the xFetch() method will be invoked again with 5464** a createFlag of 2. 5465** 5466** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 5467** as its second argument. ^(If the third parameter, discard, is non-zero, 5468** then the page should be evicted from the cache. In this case SQLite 5469** assumes that the next time the page is retrieved from the cache using 5470** the xFetch() method, it will be zeroed.)^ ^If the discard parameter is 5471** zero, then the page is considered to be unpinned. ^The cache implementation 5472** may choose to evict unpinned pages at any time. 5473** 5474** ^(The cache is not required to perform any reference counting. A single 5475** call to xUnpin() unpins the page regardless of the number of prior calls 5476** to xFetch().)^ 5477** 5478** ^The xRekey() method is used to change the key value associated with the 5479** page passed as the second argument from oldKey to newKey. ^If the cache 5480** previously contains an entry associated with newKey, it should be 5481** discarded. ^Any prior cache entry associated with newKey is guaranteed not 5482** to be pinned. 5483** 5484** ^When SQLite calls the xTruncate() method, the cache must discard all 5485** existing cache entries with page numbers (keys) greater than or equal 5486** to the value of the iLimit parameter passed to xTruncate(). ^If any 5487** of these pages are pinned, they are implicitly unpinned, meaning that 5488** they can be safely discarded. 5489** 5490** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 5491** All resources associated with the specified cache should be freed. ^After 5492** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 5493** handle invalid, and will not use it with any other sqlite3_pcache_methods 5494** functions. 5495*/ 5496typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 5497struct sqlite3_pcache_methods { 5498 void *pArg; 5499 int (*xInit)(void*); 5500 void (*xShutdown)(void*); 5501 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 5502 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 5503 int (*xPagecount)(sqlite3_pcache*); 5504 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 5505 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 5506 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 5507 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 5508 void (*xDestroy)(sqlite3_pcache*); 5509}; 5510 5511/* 5512** CAPI3REF: Online Backup Object 5513** 5514** The sqlite3_backup object records state information about an ongoing 5515** online backup operation. ^The sqlite3_backup object is created by 5516** a call to [sqlite3_backup_init()] and is destroyed by a call to 5517** [sqlite3_backup_finish()]. 5518** 5519** See Also: [Using the SQLite Online Backup API] 5520*/ 5521typedef struct sqlite3_backup sqlite3_backup; 5522 5523/* 5524** CAPI3REF: Online Backup API. 5525** 5526** The backup API copies the content of one database into another. 5527** It is useful either for creating backups of databases or 5528** for copying in-memory databases to or from persistent files. 5529** 5530** See Also: [Using the SQLite Online Backup API] 5531** 5532** ^Exclusive access is required to the destination database for the 5533** duration of the operation. ^However the source database is only 5534** read-locked while it is actually being read; it is not locked 5535** continuously for the entire backup operation. ^Thus, the backup may be 5536** performed on a live source database without preventing other users from 5537** reading or writing to the source database while the backup is underway. 5538** 5539** ^(To perform a backup operation: 5540** <ol> 5541** <li><b>sqlite3_backup_init()</b> is called once to initialize the 5542** backup, 5543** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 5544** the data between the two databases, and finally 5545** <li><b>sqlite3_backup_finish()</b> is called to release all resources 5546** associated with the backup operation. 5547** </ol>)^ 5548** There should be exactly one call to sqlite3_backup_finish() for each 5549** successful call to sqlite3_backup_init(). 5550** 5551** <b>sqlite3_backup_init()</b> 5552** 5553** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 5554** [database connection] associated with the destination database 5555** and the database name, respectively. 5556** ^The database name is "main" for the main database, "temp" for the 5557** temporary database, or the name specified after the AS keyword in 5558** an [ATTACH] statement for an attached database. 5559** ^The S and M arguments passed to 5560** sqlite3_backup_init(D,N,S,M) identify the [database connection] 5561** and database name of the source database, respectively. 5562** ^The source and destination [database connections] (parameters S and D) 5563** must be different or else sqlite3_backup_init(D,N,S,M) will file with 5564** an error. 5565** 5566** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 5567** returned and an error code and error message are store3d in the 5568** destination [database connection] D. 5569** ^The error code and message for the failed call to sqlite3_backup_init() 5570** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 5571** [sqlite3_errmsg16()] functions. 5572** ^A successful call to sqlite3_backup_init() returns a pointer to an 5573** [sqlite3_backup] object. 5574** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 5575** sqlite3_backup_finish() functions to perform the specified backup 5576** operation. 5577** 5578** <b>sqlite3_backup_step()</b> 5579** 5580** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 5581** the source and destination databases specified by [sqlite3_backup] object B. 5582** ^If N is negative, all remaining source pages are copied. 5583** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 5584** are still more pages to be copied, then the function resturns [SQLITE_OK]. 5585** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 5586** from source to destination, then it returns [SQLITE_DONE]. 5587** ^If an error occurs while running sqlite3_backup_step(B,N), 5588** then an [error code] is returned. ^As well as [SQLITE_OK] and 5589** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 5590** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 5591** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 5592** 5593** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 5594** <ol> 5595** <li> the destination database was opened read-only, or 5596** <li> the destination database is using write-ahead-log journaling 5597** and the destination and source page sizes differ, or 5598** <li> The destination database is an in-memory database and the 5599** destination and source page sizes differ. 5600** </ol>)^ 5601** 5602** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 5603** the [sqlite3_busy_handler | busy-handler function] 5604** is invoked (if one is specified). ^If the 5605** busy-handler returns non-zero before the lock is available, then 5606** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 5607** sqlite3_backup_step() can be retried later. ^If the source 5608** [database connection] 5609** is being used to write to the source database when sqlite3_backup_step() 5610** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 5611** case the call to sqlite3_backup_step() can be retried later on. ^(If 5612** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 5613** [SQLITE_READONLY] is returned, then 5614** there is no point in retrying the call to sqlite3_backup_step(). These 5615** errors are considered fatal.)^ The application must accept 5616** that the backup operation has failed and pass the backup operation handle 5617** to the sqlite3_backup_finish() to release associated resources. 5618** 5619** ^The first call to sqlite3_backup_step() obtains an exclusive lock 5620** on the destination file. ^The exclusive lock is not released until either 5621** sqlite3_backup_finish() is called or the backup operation is complete 5622** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 5623** sqlite3_backup_step() obtains a [shared lock] on the source database that 5624** lasts for the duration of the sqlite3_backup_step() call. 5625** ^Because the source database is not locked between calls to 5626** sqlite3_backup_step(), the source database may be modified mid-way 5627** through the backup process. ^If the source database is modified by an 5628** external process or via a database connection other than the one being 5629** used by the backup operation, then the backup will be automatically 5630** restarted by the next call to sqlite3_backup_step(). ^If the source 5631** database is modified by the using the same database connection as is used 5632** by the backup operation, then the backup database is automatically 5633** updated at the same time. 5634** 5635** <b>sqlite3_backup_finish()</b> 5636** 5637** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 5638** application wishes to abandon the backup operation, the application 5639** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 5640** ^The sqlite3_backup_finish() interfaces releases all 5641** resources associated with the [sqlite3_backup] object. 5642** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 5643** active write-transaction on the destination database is rolled back. 5644** The [sqlite3_backup] object is invalid 5645** and may not be used following a call to sqlite3_backup_finish(). 5646** 5647** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 5648** sqlite3_backup_step() errors occurred, regardless or whether or not 5649** sqlite3_backup_step() completed. 5650** ^If an out-of-memory condition or IO error occurred during any prior 5651** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 5652** sqlite3_backup_finish() returns the corresponding [error code]. 5653** 5654** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 5655** is not a permanent error and does not affect the return value of 5656** sqlite3_backup_finish(). 5657** 5658** <b>sqlite3_backup_remaining(), sqlite3_backup_pagecount()</b> 5659** 5660** ^Each call to sqlite3_backup_step() sets two values inside 5661** the [sqlite3_backup] object: the number of pages still to be backed 5662** up and the total number of pages in the source database file. 5663** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces 5664** retrieve these two values, respectively. 5665** 5666** ^The values returned by these functions are only updated by 5667** sqlite3_backup_step(). ^If the source database is modified during a backup 5668** operation, then the values are not updated to account for any extra 5669** pages that need to be updated or the size of the source database file 5670** changing. 5671** 5672** <b>Concurrent Usage of Database Handles</b> 5673** 5674** ^The source [database connection] may be used by the application for other 5675** purposes while a backup operation is underway or being initialized. 5676** ^If SQLite is compiled and configured to support threadsafe database 5677** connections, then the source database connection may be used concurrently 5678** from within other threads. 5679** 5680** However, the application must guarantee that the destination 5681** [database connection] is not passed to any other API (by any thread) after 5682** sqlite3_backup_init() is called and before the corresponding call to 5683** sqlite3_backup_finish(). SQLite does not currently check to see 5684** if the application incorrectly accesses the destination [database connection] 5685** and so no error code is reported, but the operations may malfunction 5686** nevertheless. Use of the destination database connection while a 5687** backup is in progress might also also cause a mutex deadlock. 5688** 5689** If running in [shared cache mode], the application must 5690** guarantee that the shared cache used by the destination database 5691** is not accessed while the backup is running. In practice this means 5692** that the application must guarantee that the disk file being 5693** backed up to is not accessed by any connection within the process, 5694** not just the specific connection that was passed to sqlite3_backup_init(). 5695** 5696** The [sqlite3_backup] object itself is partially threadsafe. Multiple 5697** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 5698** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 5699** APIs are not strictly speaking threadsafe. If they are invoked at the 5700** same time as another thread is invoking sqlite3_backup_step() it is 5701** possible that they return invalid values. 5702*/ 5703SQLITE_API sqlite3_backup *sqlite3_backup_init( 5704 sqlite3 *pDest, /* Destination database handle */ 5705 const char *zDestName, /* Destination database name */ 5706 sqlite3 *pSource, /* Source database handle */ 5707 const char *zSourceName /* Source database name */ 5708); 5709SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage); 5710SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p); 5711SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p); 5712SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p); 5713 5714/* 5715** CAPI3REF: Unlock Notification 5716** 5717** ^When running in shared-cache mode, a database operation may fail with 5718** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 5719** individual tables within the shared-cache cannot be obtained. See 5720** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 5721** ^This API may be used to register a callback that SQLite will invoke 5722** when the connection currently holding the required lock relinquishes it. 5723** ^This API is only available if the library was compiled with the 5724** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 5725** 5726** See Also: [Using the SQLite Unlock Notification Feature]. 5727** 5728** ^Shared-cache locks are released when a database connection concludes 5729** its current transaction, either by committing it or rolling it back. 5730** 5731** ^When a connection (known as the blocked connection) fails to obtain a 5732** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 5733** identity of the database connection (the blocking connection) that 5734** has locked the required resource is stored internally. ^After an 5735** application receives an SQLITE_LOCKED error, it may call the 5736** sqlite3_unlock_notify() method with the blocked connection handle as 5737** the first argument to register for a callback that will be invoked 5738** when the blocking connections current transaction is concluded. ^The 5739** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 5740** call that concludes the blocking connections transaction. 5741** 5742** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 5743** there is a chance that the blocking connection will have already 5744** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 5745** If this happens, then the specified callback is invoked immediately, 5746** from within the call to sqlite3_unlock_notify().)^ 5747** 5748** ^If the blocked connection is attempting to obtain a write-lock on a 5749** shared-cache table, and more than one other connection currently holds 5750** a read-lock on the same table, then SQLite arbitrarily selects one of 5751** the other connections to use as the blocking connection. 5752** 5753** ^(There may be at most one unlock-notify callback registered by a 5754** blocked connection. If sqlite3_unlock_notify() is called when the 5755** blocked connection already has a registered unlock-notify callback, 5756** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 5757** called with a NULL pointer as its second argument, then any existing 5758** unlock-notify callback is canceled. ^The blocked connections 5759** unlock-notify callback may also be canceled by closing the blocked 5760** connection using [sqlite3_close()]. 5761** 5762** The unlock-notify callback is not reentrant. If an application invokes 5763** any sqlite3_xxx API functions from within an unlock-notify callback, a 5764** crash or deadlock may be the result. 5765** 5766** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 5767** returns SQLITE_OK. 5768** 5769** <b>Callback Invocation Details</b> 5770** 5771** When an unlock-notify callback is registered, the application provides a 5772** single void* pointer that is passed to the callback when it is invoked. 5773** However, the signature of the callback function allows SQLite to pass 5774** it an array of void* context pointers. The first argument passed to 5775** an unlock-notify callback is a pointer to an array of void* pointers, 5776** and the second is the number of entries in the array. 5777** 5778** When a blocking connections transaction is concluded, there may be 5779** more than one blocked connection that has registered for an unlock-notify 5780** callback. ^If two or more such blocked connections have specified the 5781** same callback function, then instead of invoking the callback function 5782** multiple times, it is invoked once with the set of void* context pointers 5783** specified by the blocked connections bundled together into an array. 5784** This gives the application an opportunity to prioritize any actions 5785** related to the set of unblocked database connections. 5786** 5787** <b>Deadlock Detection</b> 5788** 5789** Assuming that after registering for an unlock-notify callback a 5790** database waits for the callback to be issued before taking any further 5791** action (a reasonable assumption), then using this API may cause the 5792** application to deadlock. For example, if connection X is waiting for 5793** connection Y's transaction to be concluded, and similarly connection 5794** Y is waiting on connection X's transaction, then neither connection 5795** will proceed and the system may remain deadlocked indefinitely. 5796** 5797** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 5798** detection. ^If a given call to sqlite3_unlock_notify() would put the 5799** system in a deadlocked state, then SQLITE_LOCKED is returned and no 5800** unlock-notify callback is registered. The system is said to be in 5801** a deadlocked state if connection A has registered for an unlock-notify 5802** callback on the conclusion of connection B's transaction, and connection 5803** B has itself registered for an unlock-notify callback when connection 5804** A's transaction is concluded. ^Indirect deadlock is also detected, so 5805** the system is also considered to be deadlocked if connection B has 5806** registered for an unlock-notify callback on the conclusion of connection 5807** C's transaction, where connection C is waiting on connection A. ^Any 5808** number of levels of indirection are allowed. 5809** 5810** <b>The "DROP TABLE" Exception</b> 5811** 5812** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 5813** always appropriate to call sqlite3_unlock_notify(). There is however, 5814** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 5815** SQLite checks if there are any currently executing SELECT statements 5816** that belong to the same connection. If there are, SQLITE_LOCKED is 5817** returned. In this case there is no "blocking connection", so invoking 5818** sqlite3_unlock_notify() results in the unlock-notify callback being 5819** invoked immediately. If the application then re-attempts the "DROP TABLE" 5820** or "DROP INDEX" query, an infinite loop might be the result. 5821** 5822** One way around this problem is to check the extended error code returned 5823** by an sqlite3_step() call. ^(If there is a blocking connection, then the 5824** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 5825** the special "DROP TABLE/INDEX" case, the extended error code is just 5826** SQLITE_LOCKED.)^ 5827*/ 5828SQLITE_API int sqlite3_unlock_notify( 5829 sqlite3 *pBlocked, /* Waiting connection */ 5830 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 5831 void *pNotifyArg /* Argument to pass to xNotify */ 5832); 5833 5834 5835/* 5836** CAPI3REF: String Comparison 5837** 5838** ^The [sqlite3_strnicmp()] API allows applications and extensions to 5839** compare the contents of two buffers containing UTF-8 strings in a 5840** case-independent fashion, using the same definition of case independence 5841** that SQLite uses internally when comparing identifiers. 5842*/ 5843SQLITE_API int sqlite3_strnicmp(const char *, const char *, int); 5844 5845/* 5846** CAPI3REF: Error Logging Interface 5847** 5848** ^The [sqlite3_log()] interface writes a message into the error log 5849** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 5850** ^If logging is enabled, the zFormat string and subsequent arguments are 5851** used with [sqlite3_snprintf()] to generate the final output string. 5852** 5853** The sqlite3_log() interface is intended for use by extensions such as 5854** virtual tables, collating functions, and SQL functions. While there is 5855** nothing to prevent an application from calling sqlite3_log(), doing so 5856** is considered bad form. 5857** 5858** The zFormat string must not be NULL. 5859** 5860** To avoid deadlocks and other threading problems, the sqlite3_log() routine 5861** will not use dynamically allocated memory. The log message is stored in 5862** a fixed-length buffer on the stack. If the log message is longer than 5863** a few hundred characters, it will be truncated to the length of the 5864** buffer. 5865*/ 5866SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...); 5867 5868/* 5869** CAPI3REF: Write-Ahead Log Commit Hook 5870** 5871** ^The [sqlite3_wal_hook()] function is used to register a callback that 5872** will be invoked each time a database connection commits data to a 5873** [write-ahead log] (i.e. whenever a transaction is committed in 5874** [journal_mode | journal_mode=WAL mode]). 5875** 5876** ^The callback is invoked by SQLite after the commit has taken place and 5877** the associated write-lock on the database released, so the implementation 5878** may read, write or [checkpoint] the database as required. 5879** 5880** ^The first parameter passed to the callback function when it is invoked 5881** is a copy of the third parameter passed to sqlite3_wal_hook() when 5882** registering the callback. ^The second is a copy of the database handle. 5883** ^The third parameter is the name of the database that was written to - 5884** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 5885** is the number of pages currently in the write-ahead log file, 5886** including those that were just committed. 5887** 5888** The callback function should normally return [SQLITE_OK]. ^If an error 5889** code is returned, that error will propagate back up through the 5890** SQLite code base to cause the statement that provoked the callback 5891** to report an error, though the commit will have still occurred. If the 5892** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 5893** that does not correspond to any valid SQLite error code, the results 5894** are undefined. 5895** 5896** A single database handle may have at most a single write-ahead log callback 5897** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 5898** previously registered write-ahead log callback. ^Note that the 5899** [sqlite3_wal_autocheckpoint()] interface and the 5900** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 5901** those overwrite any prior [sqlite3_wal_hook()] settings. 5902*/ 5903SQLITE_API void *sqlite3_wal_hook( 5904 sqlite3*, 5905 int(*)(void *,sqlite3*,const char*,int), 5906 void* 5907); 5908 5909/* 5910** CAPI3REF: Configure an auto-checkpoint 5911** 5912** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 5913** [sqlite3_wal_hook()] that causes any database on [database connection] D 5914** to automatically [checkpoint] 5915** after committing a transaction if there are N or 5916** more frames in the [write-ahead log] file. ^Passing zero or 5917** a negative value as the nFrame parameter disables automatic 5918** checkpoints entirely. 5919** 5920** ^The callback registered by this function replaces any existing callback 5921** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 5922** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 5923** configured by this function. 5924** 5925** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 5926** from SQL. 5927** 5928** ^Every new [database connection] defaults to having the auto-checkpoint 5929** enabled with a threshold of 1000 pages. The use of this interface 5930** is only necessary if the default setting is found to be suboptimal 5931** for a particular application. 5932*/ 5933SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 5934 5935/* 5936** CAPI3REF: Checkpoint a database 5937** 5938** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X 5939** on [database connection] D to be [checkpointed]. ^If X is NULL or an 5940** empty string, then a checkpoint is run on all databases of 5941** connection D. ^If the database connection D is not in 5942** [WAL | write-ahead log mode] then this interface is a harmless no-op. 5943** 5944** ^The [wal_checkpoint pragma] can be used to invoke this interface 5945** from SQL. ^The [sqlite3_wal_autocheckpoint()] interface and the 5946** [wal_autocheckpoint pragma] can be used to cause this interface to be 5947** run whenever the WAL reaches a certain size threshold. 5948*/ 5949SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 5950 5951/* 5952** Undo the hack that converts floating point types to integer for 5953** builds on processors without floating point support. 5954*/ 5955#ifdef SQLITE_OMIT_FLOATING_POINT 5956# undef double 5957#endif 5958 5959#ifdef __cplusplus 5960} /* End of the 'extern "C"' block */ 5961#endif 5962#endif 5963 5964