1/* 2** 2001 September 15 3** 4** The author disclaims copyright to this source code. In place of 5** a legal notice, here is a blessing: 6** 7** May you do good and not evil. 8** May you find forgiveness for yourself and forgive others. 9** May you share freely, never taking more than you give. 10** 11************************************************************************* 12** This header file defines the interface that the SQLite library 13** presents to client programs. If a C-function, structure, datatype, 14** or constant definition does not appear in this file, then it is 15** not a published API of SQLite, is subject to change without 16** notice, and should not be referenced by programs that use SQLite. 17** 18** Some of the definitions that are in this file are marked as 19** "experimental". Experimental interfaces are normally new 20** features recently added to SQLite. We do not anticipate changes 21** to experimental interfaces but reserve the right to make minor changes 22** if experience from use "in the wild" suggest such changes are prudent. 23** 24** The official C-language API documentation for SQLite is derived 25** from comments in this file. This file is the authoritative source 26** on how SQLite interfaces are suppose to operate. 27** 28** The name of this file under configuration management is "sqlite.h.in". 29** The makefile makes some minor changes to this file (such as inserting 30** the version number) and changes its name to "sqlite3.h" as 31** part of the build process. 32*/ 33#ifndef _SQLITE3_H_ 34#define _SQLITE3_H_ 35#include <stdarg.h> /* Needed for the definition of va_list */ 36 37/* 38** Make sure we can call this stuff from C++. 39*/ 40#ifdef __cplusplus 41extern "C" { 42#endif 43 44 45/* 46** Add the ability to override 'extern' 47*/ 48#ifndef SQLITE_EXTERN 49# define SQLITE_EXTERN extern 50#endif 51 52/* 53** These no-op macros are used in front of interfaces to mark those 54** interfaces as either deprecated or experimental. New applications 55** should not use deprecated interfaces - they are support for backwards 56** compatibility only. Application writers should be aware that 57** experimental interfaces are subject to change in point releases. 58** 59** These macros used to resolve to various kinds of compiler magic that 60** would generate warning messages when they were used. But that 61** compiler magic ended up generating such a flurry of bug reports 62** that we have taken it all out and gone back to using simple 63** noop macros. 64*/ 65#define SQLITE_DEPRECATED 66#define SQLITE_EXPERIMENTAL 67 68/* 69** Ensure these symbols were not defined by some previous header file. 70*/ 71#ifdef SQLITE_VERSION 72# undef SQLITE_VERSION 73#endif 74#ifdef SQLITE_VERSION_NUMBER 75# undef SQLITE_VERSION_NUMBER 76#endif 77 78/* 79** CAPI3REF: Compile-Time Library Version Numbers 80** 81** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header 82** evaluates to a string literal that is the SQLite version in the 83** format "X.Y.Z" where X is the major version number (always 3 for 84** SQLite3) and Y is the minor version number and Z is the release number.)^ 85** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer 86** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same 87** numbers used in [SQLITE_VERSION].)^ 88** The SQLITE_VERSION_NUMBER for any given release of SQLite will also 89** be larger than the release from which it is derived. Either Y will 90** be held constant and Z will be incremented or else Y will be incremented 91** and Z will be reset to zero. 92** 93** Since version 3.6.18, SQLite source code has been stored in the 94** <a href="http://www.fossil-scm.org/">Fossil configuration management 95** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to 96** a string which identifies a particular check-in of SQLite 97** within its configuration management system. ^The SQLITE_SOURCE_ID 98** string contains the date and time of the check-in (UTC) and an SHA1 99** hash of the entire source tree. 100** 101** See also: [sqlite3_libversion()], 102** [sqlite3_libversion_number()], [sqlite3_sourceid()], 103** [sqlite_version()] and [sqlite_source_id()]. 104*/ 105#define SQLITE_VERSION "--VERS--" 106#define SQLITE_VERSION_NUMBER --VERSION-NUMBER-- 107#define SQLITE_SOURCE_ID "--SOURCE-ID--" 108 109/* 110** CAPI3REF: Run-Time Library Version Numbers 111** KEYWORDS: sqlite3_version, sqlite3_sourceid 112** 113** These interfaces provide the same information as the [SQLITE_VERSION], 114** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros 115** but are associated with the library instead of the header file. ^(Cautious 116** programmers might include assert() statements in their application to 117** verify that values returned by these interfaces match the macros in 118** the header, and thus insure that the application is 119** compiled with matching library and header files. 120** 121** <blockquote><pre> 122** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER ); 123** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 ); 124** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 ); 125** </pre></blockquote>)^ 126** 127** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION] 128** macro. ^The sqlite3_libversion() function returns a pointer to the 129** to the sqlite3_version[] string constant. The sqlite3_libversion() 130** function is provided for use in DLLs since DLL users usually do not have 131** direct access to string constants within the DLL. ^The 132** sqlite3_libversion_number() function returns an integer equal to 133** [SQLITE_VERSION_NUMBER]. ^The sqlite3_sourceid() function returns 134** a pointer to a string constant whose value is the same as the 135** [SQLITE_SOURCE_ID] C preprocessor macro. 136** 137** See also: [sqlite_version()] and [sqlite_source_id()]. 138*/ 139SQLITE_EXTERN const char sqlite3_version[]; 140const char *sqlite3_libversion(void); 141const char *sqlite3_sourceid(void); 142int sqlite3_libversion_number(void); 143 144/* 145** CAPI3REF: Run-Time Library Compilation Options Diagnostics 146** 147** ^The sqlite3_compileoption_used() function returns 0 or 1 148** indicating whether the specified option was defined at 149** compile time. ^The SQLITE_ prefix may be omitted from the 150** option name passed to sqlite3_compileoption_used(). 151** 152** ^The sqlite3_compileoption_get() function allows iterating 153** over the list of options that were defined at compile time by 154** returning the N-th compile time option string. ^If N is out of range, 155** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_ 156** prefix is omitted from any strings returned by 157** sqlite3_compileoption_get(). 158** 159** ^Support for the diagnostic functions sqlite3_compileoption_used() 160** and sqlite3_compileoption_get() may be omitted by specifying the 161** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time. 162** 163** See also: SQL functions [sqlite_compileoption_used()] and 164** [sqlite_compileoption_get()] and the [compile_options pragma]. 165*/ 166#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS 167int sqlite3_compileoption_used(const char *zOptName); 168const char *sqlite3_compileoption_get(int N); 169#endif 170 171/* 172** CAPI3REF: Test To See If The Library Is Threadsafe 173** 174** ^The sqlite3_threadsafe() function returns zero if and only if 175** SQLite was compiled mutexing code omitted due to the 176** [SQLITE_THREADSAFE] compile-time option being set to 0. 177** 178** SQLite can be compiled with or without mutexes. When 179** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes 180** are enabled and SQLite is threadsafe. When the 181** [SQLITE_THREADSAFE] macro is 0, 182** the mutexes are omitted. Without the mutexes, it is not safe 183** to use SQLite concurrently from more than one thread. 184** 185** Enabling mutexes incurs a measurable performance penalty. 186** So if speed is of utmost importance, it makes sense to disable 187** the mutexes. But for maximum safety, mutexes should be enabled. 188** ^The default behavior is for mutexes to be enabled. 189** 190** This interface can be used by an application to make sure that the 191** version of SQLite that it is linking against was compiled with 192** the desired setting of the [SQLITE_THREADSAFE] macro. 193** 194** This interface only reports on the compile-time mutex setting 195** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with 196** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but 197** can be fully or partially disabled using a call to [sqlite3_config()] 198** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], 199** or [SQLITE_CONFIG_MUTEX]. ^(The return value of the 200** sqlite3_threadsafe() function shows only the compile-time setting of 201** thread safety, not any run-time changes to that setting made by 202** sqlite3_config(). In other words, the return value from sqlite3_threadsafe() 203** is unchanged by calls to sqlite3_config().)^ 204** 205** See the [threading mode] documentation for additional information. 206*/ 207int sqlite3_threadsafe(void); 208 209/* 210** CAPI3REF: Database Connection Handle 211** KEYWORDS: {database connection} {database connections} 212** 213** Each open SQLite database is represented by a pointer to an instance of 214** the opaque structure named "sqlite3". It is useful to think of an sqlite3 215** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and 216** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] 217** is its destructor. There are many other interfaces (such as 218** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 219** [sqlite3_busy_timeout()] to name but three) that are methods on an 220** sqlite3 object. 221*/ 222typedef struct sqlite3 sqlite3; 223 224/* 225** CAPI3REF: 64-Bit Integer Types 226** KEYWORDS: sqlite_int64 sqlite_uint64 227** 228** Because there is no cross-platform way to specify 64-bit integer types 229** SQLite includes typedefs for 64-bit signed and unsigned integers. 230** 231** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 232** The sqlite_int64 and sqlite_uint64 types are supported for backwards 233** compatibility only. 234** 235** ^The sqlite3_int64 and sqlite_int64 types can store integer values 236** between -9223372036854775808 and +9223372036854775807 inclusive. ^The 237** sqlite3_uint64 and sqlite_uint64 types can store integer values 238** between 0 and +18446744073709551615 inclusive. 239*/ 240#ifdef SQLITE_INT64_TYPE 241 typedef SQLITE_INT64_TYPE sqlite_int64; 242 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 243#elif defined(_MSC_VER) || defined(__BORLANDC__) 244 typedef __int64 sqlite_int64; 245 typedef unsigned __int64 sqlite_uint64; 246#else 247 typedef long long int sqlite_int64; 248 typedef unsigned long long int sqlite_uint64; 249#endif 250typedef sqlite_int64 sqlite3_int64; 251typedef sqlite_uint64 sqlite3_uint64; 252 253/* 254** If compiling for a processor that lacks floating point support, 255** substitute integer for floating-point. 256*/ 257#ifdef SQLITE_OMIT_FLOATING_POINT 258# define double sqlite3_int64 259#endif 260 261/* 262** CAPI3REF: Closing A Database Connection 263** 264** ^The sqlite3_close() routine is the destructor for the [sqlite3] object. 265** ^Calls to sqlite3_close() return SQLITE_OK if the [sqlite3] object is 266** successfully destroyed and all associated resources are deallocated. 267** 268** Applications must [sqlite3_finalize | finalize] all [prepared statements] 269** and [sqlite3_blob_close | close] all [BLOB handles] associated with 270** the [sqlite3] object prior to attempting to close the object. ^If 271** sqlite3_close() is called on a [database connection] that still has 272** outstanding [prepared statements] or [BLOB handles], then it returns 273** SQLITE_BUSY. 274** 275** ^If [sqlite3_close()] is invoked while a transaction is open, 276** the transaction is automatically rolled back. 277** 278** The C parameter to [sqlite3_close(C)] must be either a NULL 279** pointer or an [sqlite3] object pointer obtained 280** from [sqlite3_open()], [sqlite3_open16()], or 281** [sqlite3_open_v2()], and not previously closed. 282** ^Calling sqlite3_close() with a NULL pointer argument is a 283** harmless no-op. 284*/ 285int sqlite3_close(sqlite3 *); 286 287/* 288** The type for a callback function. 289** This is legacy and deprecated. It is included for historical 290** compatibility and is not documented. 291*/ 292typedef int (*sqlite3_callback)(void*,int,char**, char**); 293 294/* 295** CAPI3REF: One-Step Query Execution Interface 296** 297** The sqlite3_exec() interface is a convenience wrapper around 298** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], 299** that allows an application to run multiple statements of SQL 300** without having to use a lot of C code. 301** 302** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, 303** semicolon-separate SQL statements passed into its 2nd argument, 304** in the context of the [database connection] passed in as its 1st 305** argument. ^If the callback function of the 3rd argument to 306** sqlite3_exec() is not NULL, then it is invoked for each result row 307** coming out of the evaluated SQL statements. ^The 4th argument to 308** to sqlite3_exec() is relayed through to the 1st argument of each 309** callback invocation. ^If the callback pointer to sqlite3_exec() 310** is NULL, then no callback is ever invoked and result rows are 311** ignored. 312** 313** ^If an error occurs while evaluating the SQL statements passed into 314** sqlite3_exec(), then execution of the current statement stops and 315** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() 316** is not NULL then any error message is written into memory obtained 317** from [sqlite3_malloc()] and passed back through the 5th parameter. 318** To avoid memory leaks, the application should invoke [sqlite3_free()] 319** on error message strings returned through the 5th parameter of 320** of sqlite3_exec() after the error message string is no longer needed. 321** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors 322** occur, then sqlite3_exec() sets the pointer in its 5th parameter to 323** NULL before returning. 324** 325** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() 326** routine returns SQLITE_ABORT without invoking the callback again and 327** without running any subsequent SQL statements. 328** 329** ^The 2nd argument to the sqlite3_exec() callback function is the 330** number of columns in the result. ^The 3rd argument to the sqlite3_exec() 331** callback is an array of pointers to strings obtained as if from 332** [sqlite3_column_text()], one for each column. ^If an element of a 333** result row is NULL then the corresponding string pointer for the 334** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the 335** sqlite3_exec() callback is an array of pointers to strings where each 336** entry represents the name of corresponding result column as obtained 337** from [sqlite3_column_name()]. 338** 339** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer 340** to an empty string, or a pointer that contains only whitespace and/or 341** SQL comments, then no SQL statements are evaluated and the database 342** is not changed. 343** 344** Restrictions: 345** 346** <ul> 347** <li> The application must insure that the 1st parameter to sqlite3_exec() 348** is a valid and open [database connection]. 349** <li> The application must not close [database connection] specified by 350** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running. 351** <li> The application must not modify the SQL statement text passed into 352** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running. 353** </ul> 354*/ 355int sqlite3_exec( 356 sqlite3*, /* An open database */ 357 const char *sql, /* SQL to be evaluated */ 358 int (*callback)(void*,int,char**,char**), /* Callback function */ 359 void *, /* 1st argument to callback */ 360 char **errmsg /* Error msg written here */ 361); 362 363/* 364** CAPI3REF: Result Codes 365** KEYWORDS: SQLITE_OK {error code} {error codes} 366** KEYWORDS: {result code} {result codes} 367** 368** Many SQLite functions return an integer result code from the set shown 369** here in order to indicates success or failure. 370** 371** New error codes may be added in future versions of SQLite. 372** 373** See also: [SQLITE_IOERR_READ | extended result codes] 374*/ 375#define SQLITE_OK 0 /* Successful result */ 376/* beginning-of-error-codes */ 377#define SQLITE_ERROR 1 /* SQL error or missing database */ 378#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 379#define SQLITE_PERM 3 /* Access permission denied */ 380#define SQLITE_ABORT 4 /* Callback routine requested an abort */ 381#define SQLITE_BUSY 5 /* The database file is locked */ 382#define SQLITE_LOCKED 6 /* A table in the database is locked */ 383#define SQLITE_NOMEM 7 /* A malloc() failed */ 384#define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 385#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 386#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 387#define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 388#define SQLITE_NOTFOUND 12 /* NOT USED. Table or record not found */ 389#define SQLITE_FULL 13 /* Insertion failed because database is full */ 390#define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 391#define SQLITE_PROTOCOL 15 /* Database lock protocol error */ 392#define SQLITE_EMPTY 16 /* Database is empty */ 393#define SQLITE_SCHEMA 17 /* The database schema changed */ 394#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 395#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 396#define SQLITE_MISMATCH 20 /* Data type mismatch */ 397#define SQLITE_MISUSE 21 /* Library used incorrectly */ 398#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 399#define SQLITE_AUTH 23 /* Authorization denied */ 400#define SQLITE_FORMAT 24 /* Auxiliary database format error */ 401#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 402#define SQLITE_NOTADB 26 /* File opened that is not a database file */ 403#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 404#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 405/* end-of-error-codes */ 406 407/* 408** CAPI3REF: Extended Result Codes 409** KEYWORDS: {extended error code} {extended error codes} 410** KEYWORDS: {extended result code} {extended result codes} 411** 412** In its default configuration, SQLite API routines return one of 26 integer 413** [SQLITE_OK | result codes]. However, experience has shown that many of 414** these result codes are too coarse-grained. They do not provide as 415** much information about problems as programmers might like. In an effort to 416** address this, newer versions of SQLite (version 3.3.8 and later) include 417** support for additional result codes that provide more detailed information 418** about errors. The extended result codes are enabled or disabled 419** on a per database connection basis using the 420** [sqlite3_extended_result_codes()] API. 421** 422** Some of the available extended result codes are listed here. 423** One may expect the number of extended result codes will be expand 424** over time. Software that uses extended result codes should expect 425** to see new result codes in future releases of SQLite. 426** 427** The SQLITE_OK result code will never be extended. It will always 428** be exactly zero. 429*/ 430#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 431#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 432#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 433#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 434#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 435#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 436#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 437#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 438#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 439#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 440#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 441#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 442#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 443#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 444#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 445#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 446#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 447#define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) 448#define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) 449#define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) 450#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) 451#define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) 452#define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) 453 454/* 455** CAPI3REF: Flags For File Open Operations 456** 457** These bit values are intended for use in the 458** 3rd parameter to the [sqlite3_open_v2()] interface and 459** in the 4th parameter to the xOpen method of the 460** [sqlite3_vfs] object. 461*/ 462#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 463#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 464#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 465#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 466#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 467#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 468#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 469#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 470#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 471#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 472#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 473#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 474#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 475#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 476#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 477#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 478#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 479#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ 480 481/* 482** CAPI3REF: Device Characteristics 483** 484** The xDeviceCharacteristics method of the [sqlite3_io_methods] 485** object returns an integer which is a vector of the these 486** bit values expressing I/O characteristics of the mass storage 487** device that holds the file that the [sqlite3_io_methods] 488** refers to. 489** 490** The SQLITE_IOCAP_ATOMIC property means that all writes of 491** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 492** mean that writes of blocks that are nnn bytes in size and 493** are aligned to an address which is an integer multiple of 494** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 495** that when data is appended to a file, the data is appended 496** first then the size of the file is extended, never the other 497** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 498** information is written to disk in the same order as calls 499** to xWrite(). 500*/ 501#define SQLITE_IOCAP_ATOMIC 0x00000001 502#define SQLITE_IOCAP_ATOMIC512 0x00000002 503#define SQLITE_IOCAP_ATOMIC1K 0x00000004 504#define SQLITE_IOCAP_ATOMIC2K 0x00000008 505#define SQLITE_IOCAP_ATOMIC4K 0x00000010 506#define SQLITE_IOCAP_ATOMIC8K 0x00000020 507#define SQLITE_IOCAP_ATOMIC16K 0x00000040 508#define SQLITE_IOCAP_ATOMIC32K 0x00000080 509#define SQLITE_IOCAP_ATOMIC64K 0x00000100 510#define SQLITE_IOCAP_SAFE_APPEND 0x00000200 511#define SQLITE_IOCAP_SEQUENTIAL 0x00000400 512#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 513 514/* 515** CAPI3REF: File Locking Levels 516** 517** SQLite uses one of these integer values as the second 518** argument to calls it makes to the xLock() and xUnlock() methods 519** of an [sqlite3_io_methods] object. 520*/ 521#define SQLITE_LOCK_NONE 0 522#define SQLITE_LOCK_SHARED 1 523#define SQLITE_LOCK_RESERVED 2 524#define SQLITE_LOCK_PENDING 3 525#define SQLITE_LOCK_EXCLUSIVE 4 526 527/* 528** CAPI3REF: Synchronization Type Flags 529** 530** When SQLite invokes the xSync() method of an 531** [sqlite3_io_methods] object it uses a combination of 532** these integer values as the second argument. 533** 534** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 535** sync operation only needs to flush data to mass storage. Inode 536** information need not be flushed. If the lower four bits of the flag 537** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 538** If the lower four bits equal SQLITE_SYNC_FULL, that means 539** to use Mac OS X style fullsync instead of fsync(). 540*/ 541#define SQLITE_SYNC_NORMAL 0x00002 542#define SQLITE_SYNC_FULL 0x00003 543#define SQLITE_SYNC_DATAONLY 0x00010 544 545/* 546** CAPI3REF: OS Interface Open File Handle 547** 548** An [sqlite3_file] object represents an open file in the 549** [sqlite3_vfs | OS interface layer]. Individual OS interface 550** implementations will 551** want to subclass this object by appending additional fields 552** for their own use. The pMethods entry is a pointer to an 553** [sqlite3_io_methods] object that defines methods for performing 554** I/O operations on the open file. 555*/ 556typedef struct sqlite3_file sqlite3_file; 557struct sqlite3_file { 558 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 559}; 560 561/* 562** CAPI3REF: OS Interface File Virtual Methods Object 563** 564** Every file opened by the [sqlite3_vfs] xOpen method populates an 565** [sqlite3_file] object (or, more commonly, a subclass of the 566** [sqlite3_file] object) with a pointer to an instance of this object. 567** This object defines the methods used to perform various operations 568** against the open file represented by the [sqlite3_file] object. 569** 570** If the xOpen method sets the sqlite3_file.pMethods element 571** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 572** may be invoked even if the xOpen reported that it failed. The 573** only way to prevent a call to xClose following a failed xOpen 574** is for the xOpen to set the sqlite3_file.pMethods element to NULL. 575** 576** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 577** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 578** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 579** flag may be ORed in to indicate that only the data of the file 580** and not its inode needs to be synced. 581** 582** The integer values to xLock() and xUnlock() are one of 583** <ul> 584** <li> [SQLITE_LOCK_NONE], 585** <li> [SQLITE_LOCK_SHARED], 586** <li> [SQLITE_LOCK_RESERVED], 587** <li> [SQLITE_LOCK_PENDING], or 588** <li> [SQLITE_LOCK_EXCLUSIVE]. 589** </ul> 590** xLock() increases the lock. xUnlock() decreases the lock. 591** The xCheckReservedLock() method checks whether any database connection, 592** either in this process or in some other process, is holding a RESERVED, 593** PENDING, or EXCLUSIVE lock on the file. It returns true 594** if such a lock exists and false otherwise. 595** 596** The xFileControl() method is a generic interface that allows custom 597** VFS implementations to directly control an open file using the 598** [sqlite3_file_control()] interface. The second "op" argument is an 599** integer opcode. The third argument is a generic pointer intended to 600** point to a structure that may contain arguments or space in which to 601** write return values. Potential uses for xFileControl() might be 602** functions to enable blocking locks with timeouts, to change the 603** locking strategy (for example to use dot-file locks), to inquire 604** about the status of a lock, or to break stale locks. The SQLite 605** core reserves all opcodes less than 100 for its own use. 606** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available. 607** Applications that define a custom xFileControl method should use opcodes 608** greater than 100 to avoid conflicts. 609** 610** The xSectorSize() method returns the sector size of the 611** device that underlies the file. The sector size is the 612** minimum write that can be performed without disturbing 613** other bytes in the file. The xDeviceCharacteristics() 614** method returns a bit vector describing behaviors of the 615** underlying device: 616** 617** <ul> 618** <li> [SQLITE_IOCAP_ATOMIC] 619** <li> [SQLITE_IOCAP_ATOMIC512] 620** <li> [SQLITE_IOCAP_ATOMIC1K] 621** <li> [SQLITE_IOCAP_ATOMIC2K] 622** <li> [SQLITE_IOCAP_ATOMIC4K] 623** <li> [SQLITE_IOCAP_ATOMIC8K] 624** <li> [SQLITE_IOCAP_ATOMIC16K] 625** <li> [SQLITE_IOCAP_ATOMIC32K] 626** <li> [SQLITE_IOCAP_ATOMIC64K] 627** <li> [SQLITE_IOCAP_SAFE_APPEND] 628** <li> [SQLITE_IOCAP_SEQUENTIAL] 629** </ul> 630** 631** The SQLITE_IOCAP_ATOMIC property means that all writes of 632** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 633** mean that writes of blocks that are nnn bytes in size and 634** are aligned to an address which is an integer multiple of 635** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 636** that when data is appended to a file, the data is appended 637** first then the size of the file is extended, never the other 638** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 639** information is written to disk in the same order as calls 640** to xWrite(). 641** 642** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 643** in the unread portions of the buffer with zeros. A VFS that 644** fails to zero-fill short reads might seem to work. However, 645** failure to zero-fill short reads will eventually lead to 646** database corruption. 647*/ 648typedef struct sqlite3_io_methods sqlite3_io_methods; 649struct sqlite3_io_methods { 650 int iVersion; 651 int (*xClose)(sqlite3_file*); 652 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 653 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 654 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 655 int (*xSync)(sqlite3_file*, int flags); 656 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 657 int (*xLock)(sqlite3_file*, int); 658 int (*xUnlock)(sqlite3_file*, int); 659 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 660 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 661 int (*xSectorSize)(sqlite3_file*); 662 int (*xDeviceCharacteristics)(sqlite3_file*); 663 /* Methods above are valid for version 1 */ 664 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 665 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 666 void (*xShmBarrier)(sqlite3_file*); 667 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); 668 /* Methods above are valid for version 2 */ 669 /* Additional methods may be added in future releases */ 670}; 671 672/* 673** CAPI3REF: Standard File Control Opcodes 674** 675** These integer constants are opcodes for the xFileControl method 676** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 677** interface. 678** 679** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 680** opcode causes the xFileControl method to write the current state of 681** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 682** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 683** into an integer that the pArg argument points to. This capability 684** is used during testing and only needs to be supported when SQLITE_TEST 685** is defined. 686** 687** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 688** layer a hint of how large the database file will grow to be during the 689** current transaction. This hint is not guaranteed to be accurate but it 690** is often close. The underlying VFS might choose to preallocate database 691** file space based on this hint in order to help writes to the database 692** file run faster. 693** 694** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 695** extends and truncates the database file in chunks of a size specified 696** by the user. The fourth argument to [sqlite3_file_control()] should 697** point to an integer (type int) containing the new chunk-size to use 698** for the nominated database. Allocating database file space in large 699** chunks (say 1MB at a time), may reduce file-system fragmentation and 700** improve performance on some systems. 701*/ 702#define SQLITE_FCNTL_LOCKSTATE 1 703#define SQLITE_GET_LOCKPROXYFILE 2 704#define SQLITE_SET_LOCKPROXYFILE 3 705#define SQLITE_LAST_ERRNO 4 706#define SQLITE_FCNTL_SIZE_HINT 5 707#define SQLITE_FCNTL_CHUNK_SIZE 6 708 709/* 710** CAPI3REF: Mutex Handle 711** 712** The mutex module within SQLite defines [sqlite3_mutex] to be an 713** abstract type for a mutex object. The SQLite core never looks 714** at the internal representation of an [sqlite3_mutex]. It only 715** deals with pointers to the [sqlite3_mutex] object. 716** 717** Mutexes are created using [sqlite3_mutex_alloc()]. 718*/ 719typedef struct sqlite3_mutex sqlite3_mutex; 720 721/* 722** CAPI3REF: OS Interface Object 723** 724** An instance of the sqlite3_vfs object defines the interface between 725** the SQLite core and the underlying operating system. The "vfs" 726** in the name of the object stands for "virtual file system". 727** 728** The value of the iVersion field is initially 1 but may be larger in 729** future versions of SQLite. Additional fields may be appended to this 730** object when the iVersion value is increased. Note that the structure 731** of the sqlite3_vfs object changes in the transaction between 732** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 733** modified. 734** 735** The szOsFile field is the size of the subclassed [sqlite3_file] 736** structure used by this VFS. mxPathname is the maximum length of 737** a pathname in this VFS. 738** 739** Registered sqlite3_vfs objects are kept on a linked list formed by 740** the pNext pointer. The [sqlite3_vfs_register()] 741** and [sqlite3_vfs_unregister()] interfaces manage this list 742** in a thread-safe way. The [sqlite3_vfs_find()] interface 743** searches the list. Neither the application code nor the VFS 744** implementation should use the pNext pointer. 745** 746** The pNext field is the only field in the sqlite3_vfs 747** structure that SQLite will ever modify. SQLite will only access 748** or modify this field while holding a particular static mutex. 749** The application should never modify anything within the sqlite3_vfs 750** object once the object has been registered. 751** 752** The zName field holds the name of the VFS module. The name must 753** be unique across all VFS modules. 754** 755** ^SQLite guarantees that the zFilename parameter to xOpen 756** is either a NULL pointer or string obtained 757** from xFullPathname() with an optional suffix added. 758** ^If a suffix is added to the zFilename parameter, it will 759** consist of a single "-" character followed by no more than 760** 10 alphanumeric and/or "-" characters. 761** ^SQLite further guarantees that 762** the string will be valid and unchanged until xClose() is 763** called. Because of the previous sentence, 764** the [sqlite3_file] can safely store a pointer to the 765** filename if it needs to remember the filename for some reason. 766** If the zFilename parameter to xOpen is a NULL pointer then xOpen 767** must invent its own temporary name for the file. ^Whenever the 768** xFilename parameter is NULL it will also be the case that the 769** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 770** 771** The flags argument to xOpen() includes all bits set in 772** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 773** or [sqlite3_open16()] is used, then flags includes at least 774** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 775** If xOpen() opens a file read-only then it sets *pOutFlags to 776** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 777** 778** ^(SQLite will also add one of the following flags to the xOpen() 779** call, depending on the object being opened: 780** 781** <ul> 782** <li> [SQLITE_OPEN_MAIN_DB] 783** <li> [SQLITE_OPEN_MAIN_JOURNAL] 784** <li> [SQLITE_OPEN_TEMP_DB] 785** <li> [SQLITE_OPEN_TEMP_JOURNAL] 786** <li> [SQLITE_OPEN_TRANSIENT_DB] 787** <li> [SQLITE_OPEN_SUBJOURNAL] 788** <li> [SQLITE_OPEN_MASTER_JOURNAL] 789** <li> [SQLITE_OPEN_WAL] 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 and their journals, transient 811** databases, and subjournals. 812** 813** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 814** with the [SQLITE_OPEN_CREATE] flag, which are both directly 815** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 816** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 817** SQLITE_OPEN_CREATE, is used to indicate that file should always 818** be created, and that it is an error if it already exists. 819** It is <i>not</i> used to indicate the file should be opened 820** for exclusive access. 821** 822** ^At least szOsFile bytes of memory are allocated by SQLite 823** to hold the [sqlite3_file] structure passed as the third 824** argument to xOpen. The xOpen method does not have to 825** allocate the structure; it should just fill it in. Note that 826** the xOpen method must set the sqlite3_file.pMethods to either 827** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 828** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 829** element will be valid after xOpen returns regardless of the success 830** or failure of the xOpen call. 831** 832** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 833** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 834** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 835** to test whether a file is at least readable. The file can be a 836** directory. 837** 838** ^SQLite will always allocate at least mxPathname+1 bytes for the 839** output buffer xFullPathname. The exact size of the output buffer 840** is also passed as a parameter to both methods. If the output buffer 841** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 842** handled as a fatal error by SQLite, vfs implementations should endeavor 843** to prevent this by setting mxPathname to a sufficiently large value. 844** 845** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 846** interfaces are not strictly a part of the filesystem, but they are 847** included in the VFS structure for completeness. 848** The xRandomness() function attempts to return nBytes bytes 849** of good-quality randomness into zOut. The return value is 850** the actual number of bytes of randomness obtained. 851** The xSleep() method causes the calling thread to sleep for at 852** least the number of microseconds given. ^The xCurrentTime() 853** method returns a Julian Day Number for the current date and time as 854** a floating point value. 855** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 856** Day Number multipled by 86400000 (the number of milliseconds in 857** a 24-hour day). 858** ^SQLite will use the xCurrentTimeInt64() method to get the current 859** date and time if that method is available (if iVersion is 2 or 860** greater and the function pointer is not NULL) and will fall back 861** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 862*/ 863typedef struct sqlite3_vfs sqlite3_vfs; 864struct sqlite3_vfs { 865 int iVersion; /* Structure version number (currently 2) */ 866 int szOsFile; /* Size of subclassed sqlite3_file */ 867 int mxPathname; /* Maximum file pathname length */ 868 sqlite3_vfs *pNext; /* Next registered VFS */ 869 const char *zName; /* Name of this virtual file system */ 870 void *pAppData; /* Pointer to application-specific data */ 871 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 872 int flags, int *pOutFlags); 873 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 874 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 875 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 876 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 877 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 878 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 879 void (*xDlClose)(sqlite3_vfs*, void*); 880 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 881 int (*xSleep)(sqlite3_vfs*, int microseconds); 882 int (*xCurrentTime)(sqlite3_vfs*, double*); 883 int (*xGetLastError)(sqlite3_vfs*, int, char *); 884 /* 885 ** The methods above are in version 1 of the sqlite_vfs object 886 ** definition. Those that follow are added in version 2 or later 887 */ 888 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 889 /* 890 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 891 ** New fields may be appended in figure versions. The iVersion 892 ** value will increment whenever this happens. 893 */ 894}; 895 896/* 897** CAPI3REF: Flags for the xAccess VFS method 898** 899** These integer constants can be used as the third parameter to 900** the xAccess method of an [sqlite3_vfs] object. They determine 901** what kind of permissions the xAccess method is looking for. 902** With SQLITE_ACCESS_EXISTS, the xAccess method 903** simply checks whether the file exists. 904** With SQLITE_ACCESS_READWRITE, the xAccess method 905** checks whether the named directory is both readable and writable 906** (in other words, if files can be added, removed, and renamed within 907** the directory). 908** The SQLITE_ACCESS_READWRITE constant is currently used only by the 909** [temp_store_directory pragma], though this could change in a future 910** release of SQLite. 911** With SQLITE_ACCESS_READ, the xAccess method 912** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 913** currently unused, though it might be used in a future release of 914** SQLite. 915*/ 916#define SQLITE_ACCESS_EXISTS 0 917#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 918#define SQLITE_ACCESS_READ 2 /* Unused */ 919 920/* 921** CAPI3REF: Flags for the xShmLock VFS method 922** 923** These integer constants define the various locking operations 924** allowed by the xShmLock method of [sqlite3_io_methods]. The 925** following are the only legal combinations of flags to the 926** xShmLock method: 927** 928** <ul> 929** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 930** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 931** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 932** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 933** </ul> 934** 935** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 936** was given no the corresponding lock. 937** 938** The xShmLock method can transition between unlocked and SHARED or 939** between unlocked and EXCLUSIVE. It cannot transition between SHARED 940** and EXCLUSIVE. 941*/ 942#define SQLITE_SHM_UNLOCK 1 943#define SQLITE_SHM_LOCK 2 944#define SQLITE_SHM_SHARED 4 945#define SQLITE_SHM_EXCLUSIVE 8 946 947/* 948** CAPI3REF: Maximum xShmLock index 949** 950** The xShmLock method on [sqlite3_io_methods] may use values 951** between 0 and this upper bound as its "offset" argument. 952** The SQLite core will never attempt to acquire or release a 953** lock outside of this range 954*/ 955#define SQLITE_SHM_NLOCK 8 956 957 958/* 959** CAPI3REF: Initialize The SQLite Library 960** 961** ^The sqlite3_initialize() routine initializes the 962** SQLite library. ^The sqlite3_shutdown() routine 963** deallocates any resources that were allocated by sqlite3_initialize(). 964** These routines are designed to aid in process initialization and 965** shutdown on embedded systems. Workstation applications using 966** SQLite normally do not need to invoke either of these routines. 967** 968** A call to sqlite3_initialize() is an "effective" call if it is 969** the first time sqlite3_initialize() is invoked during the lifetime of 970** the process, or if it is the first time sqlite3_initialize() is invoked 971** following a call to sqlite3_shutdown(). ^(Only an effective call 972** of sqlite3_initialize() does any initialization. All other calls 973** are harmless no-ops.)^ 974** 975** A call to sqlite3_shutdown() is an "effective" call if it is the first 976** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 977** an effective call to sqlite3_shutdown() does any deinitialization. 978** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 979** 980** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 981** is not. The sqlite3_shutdown() interface must only be called from a 982** single thread. All open [database connections] must be closed and all 983** other SQLite resources must be deallocated prior to invoking 984** sqlite3_shutdown(). 985** 986** Among other things, ^sqlite3_initialize() will invoke 987** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 988** will invoke sqlite3_os_end(). 989** 990** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 991** ^If for some reason, sqlite3_initialize() is unable to initialize 992** the library (perhaps it is unable to allocate a needed resource such 993** as a mutex) it returns an [error code] other than [SQLITE_OK]. 994** 995** ^The sqlite3_initialize() routine is called internally by many other 996** SQLite interfaces so that an application usually does not need to 997** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 998** calls sqlite3_initialize() so the SQLite library will be automatically 999** initialized when [sqlite3_open()] is called if it has not be initialized 1000** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1001** compile-time option, then the automatic calls to sqlite3_initialize() 1002** are omitted and the application must call sqlite3_initialize() directly 1003** prior to using any other SQLite interface. For maximum portability, 1004** it is recommended that applications always invoke sqlite3_initialize() 1005** directly prior to using any other SQLite interface. Future releases 1006** of SQLite may require this. In other words, the behavior exhibited 1007** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1008** default behavior in some future release of SQLite. 1009** 1010** The sqlite3_os_init() routine does operating-system specific 1011** initialization of the SQLite library. The sqlite3_os_end() 1012** routine undoes the effect of sqlite3_os_init(). Typical tasks 1013** performed by these routines include allocation or deallocation 1014** of static resources, initialization of global variables, 1015** setting up a default [sqlite3_vfs] module, or setting up 1016** a default configuration using [sqlite3_config()]. 1017** 1018** The application should never invoke either sqlite3_os_init() 1019** or sqlite3_os_end() directly. The application should only invoke 1020** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1021** interface is called automatically by sqlite3_initialize() and 1022** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1023** implementations for sqlite3_os_init() and sqlite3_os_end() 1024** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1025** When [custom builds | built for other platforms] 1026** (using the [SQLITE_OS_OTHER=1] compile-time 1027** option) the application must supply a suitable implementation for 1028** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1029** implementation of sqlite3_os_init() or sqlite3_os_end() 1030** must return [SQLITE_OK] on success and some other [error code] upon 1031** failure. 1032*/ 1033int sqlite3_initialize(void); 1034int sqlite3_shutdown(void); 1035int sqlite3_os_init(void); 1036int sqlite3_os_end(void); 1037 1038/* 1039** CAPI3REF: Configuring The SQLite Library 1040** 1041** The sqlite3_config() interface is used to make global configuration 1042** changes to SQLite in order to tune SQLite to the specific needs of 1043** the application. The default configuration is recommended for most 1044** applications and so this routine is usually not necessary. It is 1045** provided to support rare applications with unusual needs. 1046** 1047** The sqlite3_config() interface is not threadsafe. The application 1048** must insure that no other SQLite interfaces are invoked by other 1049** threads while sqlite3_config() is running. Furthermore, sqlite3_config() 1050** may only be invoked prior to library initialization using 1051** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1052** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1053** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1054** Note, however, that ^sqlite3_config() can be called as part of the 1055** implementation of an application-defined [sqlite3_os_init()]. 1056** 1057** The first argument to sqlite3_config() is an integer 1058** [SQLITE_CONFIG_SINGLETHREAD | configuration option] that determines 1059** what property of SQLite is to be configured. Subsequent arguments 1060** vary depending on the [SQLITE_CONFIG_SINGLETHREAD | configuration option] 1061** in the first argument. 1062** 1063** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1064** ^If the option is unknown or SQLite is unable to set the option 1065** then this routine returns a non-zero [error code]. 1066*/ 1067int sqlite3_config(int, ...); 1068 1069/* 1070** CAPI3REF: Configure database connections 1071** 1072** The sqlite3_db_config() interface is used to make configuration 1073** changes to a [database connection]. The interface is similar to 1074** [sqlite3_config()] except that the changes apply to a single 1075** [database connection] (specified in the first argument). The 1076** sqlite3_db_config() interface should only be used immediately after 1077** the database connection is created using [sqlite3_open()], 1078** [sqlite3_open16()], or [sqlite3_open_v2()]. 1079** 1080** The second argument to sqlite3_db_config(D,V,...) is the 1081** configuration verb - an integer code that indicates what 1082** aspect of the [database connection] is being configured. 1083** The only choice for this value is [SQLITE_DBCONFIG_LOOKASIDE]. 1084** New verbs are likely to be added in future releases of SQLite. 1085** Additional arguments depend on the verb. 1086** 1087** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1088** the call is considered successful. 1089*/ 1090int sqlite3_db_config(sqlite3*, int op, ...); 1091 1092/* 1093** CAPI3REF: Memory Allocation Routines 1094** 1095** An instance of this object defines the interface between SQLite 1096** and low-level memory allocation routines. 1097** 1098** This object is used in only one place in the SQLite interface. 1099** A pointer to an instance of this object is the argument to 1100** [sqlite3_config()] when the configuration option is 1101** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1102** By creating an instance of this object 1103** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1104** during configuration, an application can specify an alternative 1105** memory allocation subsystem for SQLite to use for all of its 1106** dynamic memory needs. 1107** 1108** Note that SQLite comes with several [built-in memory allocators] 1109** that are perfectly adequate for the overwhelming majority of applications 1110** and that this object is only useful to a tiny minority of applications 1111** with specialized memory allocation requirements. This object is 1112** also used during testing of SQLite in order to specify an alternative 1113** memory allocator that simulates memory out-of-memory conditions in 1114** order to verify that SQLite recovers gracefully from such 1115** conditions. 1116** 1117** The xMalloc and xFree methods must work like the 1118** malloc() and free() functions from the standard C library. 1119** The xRealloc method must work like realloc() from the standard C library 1120** with the exception that if the second argument to xRealloc is zero, 1121** xRealloc must be a no-op - it must not perform any allocation or 1122** deallocation. ^SQLite guarantees that the second argument to 1123** xRealloc is always a value returned by a prior call to xRoundup. 1124** And so in cases where xRoundup always returns a positive number, 1125** xRealloc can perform exactly as the standard library realloc() and 1126** still be in compliance with this specification. 1127** 1128** xSize should return the allocated size of a memory allocation 1129** previously obtained from xMalloc or xRealloc. The allocated size 1130** is always at least as big as the requested size but may be larger. 1131** 1132** The xRoundup method returns what would be the allocated size of 1133** a memory allocation given a particular requested size. Most memory 1134** allocators round up memory allocations at least to the next multiple 1135** of 8. Some allocators round up to a larger multiple or to a power of 2. 1136** Every memory allocation request coming in through [sqlite3_malloc()] 1137** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1138** that causes the corresponding memory allocation to fail. 1139** 1140** The xInit method initializes the memory allocator. (For example, 1141** it might allocate any require mutexes or initialize internal data 1142** structures. The xShutdown method is invoked (indirectly) by 1143** [sqlite3_shutdown()] and should deallocate any resources acquired 1144** by xInit. The pAppData pointer is used as the only parameter to 1145** xInit and xShutdown. 1146** 1147** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1148** the xInit method, so the xInit method need not be threadsafe. The 1149** xShutdown method is only called from [sqlite3_shutdown()] so it does 1150** not need to be threadsafe either. For all other methods, SQLite 1151** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1152** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1153** it is by default) and so the methods are automatically serialized. 1154** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1155** methods must be threadsafe or else make their own arrangements for 1156** serialization. 1157** 1158** SQLite will never invoke xInit() more than once without an intervening 1159** call to xShutdown(). 1160*/ 1161typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1162struct sqlite3_mem_methods { 1163 void *(*xMalloc)(int); /* Memory allocation function */ 1164 void (*xFree)(void*); /* Free a prior allocation */ 1165 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1166 int (*xSize)(void*); /* Return the size of an allocation */ 1167 int (*xRoundup)(int); /* Round up request size to allocation size */ 1168 int (*xInit)(void*); /* Initialize the memory allocator */ 1169 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1170 void *pAppData; /* Argument to xInit() and xShutdown() */ 1171}; 1172 1173/* 1174** CAPI3REF: Configuration Options 1175** 1176** These constants are the available integer configuration options that 1177** can be passed as the first argument to the [sqlite3_config()] interface. 1178** 1179** New configuration options may be added in future releases of SQLite. 1180** Existing configuration options might be discontinued. Applications 1181** should check the return code from [sqlite3_config()] to make sure that 1182** the call worked. The [sqlite3_config()] interface will return a 1183** non-zero [error code] if a discontinued or unsupported configuration option 1184** is invoked. 1185** 1186** <dl> 1187** <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1188** <dd>There are no arguments to this option. ^This option sets the 1189** [threading mode] to Single-thread. In other words, it disables 1190** all mutexing and puts SQLite into a mode where it can only be used 1191** by a single thread. ^If SQLite is compiled with 1192** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1193** it is not possible to change the [threading mode] from its default 1194** value of Single-thread and so [sqlite3_config()] will return 1195** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1196** configuration option.</dd> 1197** 1198** <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1199** <dd>There are no arguments to this option. ^This option sets the 1200** [threading mode] to Multi-thread. In other words, it disables 1201** mutexing on [database connection] and [prepared statement] objects. 1202** The application is responsible for serializing access to 1203** [database connections] and [prepared statements]. But other mutexes 1204** are enabled so that SQLite will be safe to use in a multi-threaded 1205** environment as long as no two threads attempt to use the same 1206** [database connection] at the same time. ^If SQLite is compiled with 1207** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1208** it is not possible to set the Multi-thread [threading mode] and 1209** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1210** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1211** 1212** <dt>SQLITE_CONFIG_SERIALIZED</dt> 1213** <dd>There are no arguments to this option. ^This option sets the 1214** [threading mode] to Serialized. In other words, this option enables 1215** all mutexes including the recursive 1216** mutexes on [database connection] and [prepared statement] objects. 1217** In this mode (which is the default when SQLite is compiled with 1218** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1219** to [database connections] and [prepared statements] so that the 1220** application is free to use the same [database connection] or the 1221** same [prepared statement] in different threads at the same time. 1222** ^If SQLite is compiled with 1223** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1224** it is not possible to set the Serialized [threading mode] and 1225** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1226** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1227** 1228** <dt>SQLITE_CONFIG_MALLOC</dt> 1229** <dd> ^(This option takes a single argument which is a pointer to an 1230** instance of the [sqlite3_mem_methods] structure. The argument specifies 1231** alternative low-level memory allocation routines to be used in place of 1232** the memory allocation routines built into SQLite.)^ ^SQLite makes 1233** its own private copy of the content of the [sqlite3_mem_methods] structure 1234** before the [sqlite3_config()] call returns.</dd> 1235** 1236** <dt>SQLITE_CONFIG_GETMALLOC</dt> 1237** <dd> ^(This option takes a single argument which is a pointer to an 1238** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods] 1239** structure is filled with the currently defined memory allocation routines.)^ 1240** This option can be used to overload the default memory allocation 1241** routines with a wrapper that simulations memory allocation failure or 1242** tracks memory usage, for example. </dd> 1243** 1244** <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1245** <dd> ^This option takes single argument of type int, interpreted as a 1246** boolean, which enables or disables the collection of memory allocation 1247** statistics. ^(When memory allocation statistics are disabled, the 1248** following SQLite interfaces become non-operational: 1249** <ul> 1250** <li> [sqlite3_memory_used()] 1251** <li> [sqlite3_memory_highwater()] 1252** <li> [sqlite3_soft_heap_limit64()] 1253** <li> [sqlite3_status()] 1254** </ul>)^ 1255** ^Memory allocation statistics are enabled by default unless SQLite is 1256** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1257** allocation statistics are disabled by default. 1258** </dd> 1259** 1260** <dt>SQLITE_CONFIG_SCRATCH</dt> 1261** <dd> ^This option specifies a static memory buffer that SQLite can use for 1262** scratch memory. There are three arguments: A pointer an 8-byte 1263** aligned memory buffer from which the scrach allocations will be 1264** drawn, the size of each scratch allocation (sz), 1265** and the maximum number of scratch allocations (N). The sz 1266** argument must be a multiple of 16. 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 two scratch buffers per thread. So 1270** N should be set to twice the expected maximum number of threads. 1271** ^SQLite will never require a scratch buffer that is more than 6 1272** times the database page size. ^If SQLite needs needs additional 1273** scratch memory beyond 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 pointer in the first argument must 1294** be aligned to an 8-byte boundary or subsequent behavior of SQLite 1295** will be undefined.</dd> 1296** 1297** <dt>SQLITE_CONFIG_HEAP</dt> 1298** <dd> ^This option specifies a static memory buffer that SQLite will use 1299** for all of its dynamic memory allocation needs beyond those provided 1300** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE]. 1301** There are three arguments: An 8-byte aligned pointer to the memory, 1302** the number of bytes in the memory buffer, and the minimum allocation size. 1303** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1304** to using its default memory allocator (the system malloc() implementation), 1305** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1306** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or 1307** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory 1308** allocator is engaged to handle all of SQLites memory allocation needs. 1309** The first pointer (the memory pointer) must be aligned to an 8-byte 1310** boundary or subsequent behavior of SQLite will be undefined.</dd> 1311** 1312** <dt>SQLITE_CONFIG_MUTEX</dt> 1313** <dd> ^(This option takes a single argument which is a pointer to an 1314** instance of the [sqlite3_mutex_methods] structure. The argument specifies 1315** alternative low-level mutex routines to be used in place 1316** the mutex routines built into SQLite.)^ ^SQLite makes a copy of the 1317** content of the [sqlite3_mutex_methods] structure before the call to 1318** [sqlite3_config()] returns. ^If SQLite is compiled with 1319** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1320** the entire mutexing subsystem is omitted from the build and hence calls to 1321** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1322** return [SQLITE_ERROR].</dd> 1323** 1324** <dt>SQLITE_CONFIG_GETMUTEX</dt> 1325** <dd> ^(This option takes a single argument which is a pointer to an 1326** instance of the [sqlite3_mutex_methods] structure. The 1327** [sqlite3_mutex_methods] 1328** structure is filled with the currently defined mutex routines.)^ 1329** This option can be used to overload the default mutex allocation 1330** routines with a wrapper used to track mutex usage for performance 1331** profiling or testing, for example. ^If SQLite is compiled with 1332** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1333** the entire mutexing subsystem is omitted from the build and hence calls to 1334** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1335** return [SQLITE_ERROR].</dd> 1336** 1337** <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1338** <dd> ^(This option takes two arguments that determine the default 1339** memory allocation for the lookaside memory allocator on each 1340** [database connection]. The first argument is the 1341** size of each lookaside buffer slot and the second is the number of 1342** slots allocated to each database connection.)^ ^(This option sets the 1343** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1344** verb to [sqlite3_db_config()] can be used to change the lookaside 1345** configuration on individual connections.)^ </dd> 1346** 1347** <dt>SQLITE_CONFIG_PCACHE</dt> 1348** <dd> ^(This option takes a single argument which is a pointer to 1349** an [sqlite3_pcache_methods] object. This object specifies the interface 1350** to a custom page cache implementation.)^ ^SQLite makes a copy of the 1351** object and uses it for page cache memory allocations.</dd> 1352** 1353** <dt>SQLITE_CONFIG_GETPCACHE</dt> 1354** <dd> ^(This option takes a single argument which is a pointer to an 1355** [sqlite3_pcache_methods] object. SQLite copies of the current 1356** page cache implementation into that object.)^ </dd> 1357** 1358** <dt>SQLITE_CONFIG_LOG</dt> 1359** <dd> ^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1360** function with a call signature of void(*)(void*,int,const char*), 1361** and a pointer to void. ^If the function pointer is not NULL, it is 1362** invoked by [sqlite3_log()] to process each logging event. ^If the 1363** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1364** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1365** passed through as the first parameter to the application-defined logger 1366** function whenever that function is invoked. ^The second parameter to 1367** the logger function is a copy of the first parameter to the corresponding 1368** [sqlite3_log()] call and is intended to be a [result code] or an 1369** [extended result code]. ^The third parameter passed to the logger is 1370** log message after formatting via [sqlite3_snprintf()]. 1371** The SQLite logging interface is not reentrant; the logger function 1372** supplied by the application must not invoke any SQLite interface. 1373** In a multi-threaded application, the application-defined logger 1374** function must be threadsafe. </dd> 1375** 1376** </dl> 1377*/ 1378#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1379#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1380#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1381#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1382#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1383#define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1384#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1385#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1386#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1387#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1388#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1389/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1390#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1391#define SQLITE_CONFIG_PCACHE 14 /* sqlite3_pcache_methods* */ 1392#define SQLITE_CONFIG_GETPCACHE 15 /* sqlite3_pcache_methods* */ 1393#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1394 1395/* 1396** CAPI3REF: Database Connection Configuration Options 1397** 1398** These constants are the available integer configuration options that 1399** can be passed as the second argument to the [sqlite3_db_config()] interface. 1400** 1401** New configuration options may be added in future releases of SQLite. 1402** Existing configuration options might be discontinued. Applications 1403** should check the return code from [sqlite3_db_config()] to make sure that 1404** the call worked. ^The [sqlite3_db_config()] interface will return a 1405** non-zero [error code] if a discontinued or unsupported configuration option 1406** is invoked. 1407** 1408** <dl> 1409** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1410** <dd> ^This option takes three additional arguments that determine the 1411** [lookaside memory allocator] configuration for the [database connection]. 1412** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1413** pointer to an memory buffer to use for lookaside memory. 1414** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1415** may be NULL in which case SQLite will allocate the 1416** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1417** size of each lookaside buffer slot. ^The third argument is the number of 1418** slots. The size of the buffer in the first argument must be greater than 1419** or equal to the product of the second and third arguments. The buffer 1420** must be aligned to an 8-byte boundary. ^If the second argument to 1421** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1422** rounded down to the next smaller multiple of 8. ^(The lookaside memory 1423** configuration for a database connection can only be changed when that 1424** connection is not currently using lookaside memory, or in other words 1425** when the "current value" returned by 1426** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 1427** Any attempt to change the lookaside memory configuration when lookaside 1428** memory is in use leaves the configuration unchanged and returns 1429** [SQLITE_BUSY].)^</dd> 1430** 1431** </dl> 1432*/ 1433#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 1434 1435 1436/* 1437** CAPI3REF: Enable Or Disable Extended Result Codes 1438** 1439** ^The sqlite3_extended_result_codes() routine enables or disables the 1440** [extended result codes] feature of SQLite. ^The extended result 1441** codes are disabled by default for historical compatibility. 1442*/ 1443int sqlite3_extended_result_codes(sqlite3*, int onoff); 1444 1445/* 1446** CAPI3REF: Last Insert Rowid 1447** 1448** ^Each entry in an SQLite table has a unique 64-bit signed 1449** integer key called the [ROWID | "rowid"]. ^The rowid is always available 1450** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 1451** names are not also used by explicitly declared columns. ^If 1452** the table has a column of type [INTEGER PRIMARY KEY] then that column 1453** is another alias for the rowid. 1454** 1455** ^This routine returns the [rowid] of the most recent 1456** successful [INSERT] into the database from the [database connection] 1457** in the first argument. ^If no successful [INSERT]s 1458** have ever occurred on that database connection, zero is returned. 1459** 1460** ^(If an [INSERT] occurs within a trigger, then the [rowid] of the inserted 1461** row is returned by this routine as long as the trigger is running. 1462** But once the trigger terminates, the value returned by this routine 1463** reverts to the last value inserted before the trigger fired.)^ 1464** 1465** ^An [INSERT] that fails due to a constraint violation is not a 1466** successful [INSERT] and does not change the value returned by this 1467** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 1468** and INSERT OR ABORT make no changes to the return value of this 1469** routine when their insertion fails. ^(When INSERT OR REPLACE 1470** encounters a constraint violation, it does not fail. The 1471** INSERT continues to completion after deleting rows that caused 1472** the constraint problem so INSERT OR REPLACE will always change 1473** the return value of this interface.)^ 1474** 1475** ^For the purposes of this routine, an [INSERT] is considered to 1476** be successful even if it is subsequently rolled back. 1477** 1478** This function is accessible to SQL statements via the 1479** [last_insert_rowid() SQL function]. 1480** 1481** If a separate thread performs a new [INSERT] on the same 1482** database connection while the [sqlite3_last_insert_rowid()] 1483** function is running and thus changes the last insert [rowid], 1484** then the value returned by [sqlite3_last_insert_rowid()] is 1485** unpredictable and might not equal either the old or the new 1486** last insert [rowid]. 1487*/ 1488sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 1489 1490/* 1491** CAPI3REF: Count The Number Of Rows Modified 1492** 1493** ^This function returns the number of database rows that were changed 1494** or inserted or deleted by the most recently completed SQL statement 1495** on the [database connection] specified by the first parameter. 1496** ^(Only changes that are directly specified by the [INSERT], [UPDATE], 1497** or [DELETE] statement are counted. Auxiliary changes caused by 1498** triggers or [foreign key actions] are not counted.)^ Use the 1499** [sqlite3_total_changes()] function to find the total number of changes 1500** including changes caused by triggers and foreign key actions. 1501** 1502** ^Changes to a view that are simulated by an [INSTEAD OF trigger] 1503** are not counted. Only real table changes are counted. 1504** 1505** ^(A "row change" is a change to a single row of a single table 1506** caused by an INSERT, DELETE, or UPDATE statement. Rows that 1507** are changed as side effects of [REPLACE] constraint resolution, 1508** rollback, ABORT processing, [DROP TABLE], or by any other 1509** mechanisms do not count as direct row changes.)^ 1510** 1511** A "trigger context" is a scope of execution that begins and 1512** ends with the script of a [CREATE TRIGGER | trigger]. 1513** Most SQL statements are 1514** evaluated outside of any trigger. This is the "top level" 1515** trigger context. If a trigger fires from the top level, a 1516** new trigger context is entered for the duration of that one 1517** trigger. Subtriggers create subcontexts for their duration. 1518** 1519** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does 1520** not create a new trigger context. 1521** 1522** ^This function returns the number of direct row changes in the 1523** most recent INSERT, UPDATE, or DELETE statement within the same 1524** trigger context. 1525** 1526** ^Thus, when called from the top level, this function returns the 1527** number of changes in the most recent INSERT, UPDATE, or DELETE 1528** that also occurred at the top level. ^(Within the body of a trigger, 1529** the sqlite3_changes() interface can be called to find the number of 1530** changes in the most recently completed INSERT, UPDATE, or DELETE 1531** statement within the body of the same trigger. 1532** However, the number returned does not include changes 1533** caused by subtriggers since those have their own context.)^ 1534** 1535** See also the [sqlite3_total_changes()] interface, the 1536** [count_changes pragma], and the [changes() SQL function]. 1537** 1538** If a separate thread makes changes on the same database connection 1539** while [sqlite3_changes()] is running then the value returned 1540** is unpredictable and not meaningful. 1541*/ 1542int sqlite3_changes(sqlite3*); 1543 1544/* 1545** CAPI3REF: Total Number Of Rows Modified 1546** 1547** ^This function returns the number of row changes caused by [INSERT], 1548** [UPDATE] or [DELETE] statements since the [database connection] was opened. 1549** ^(The count returned by sqlite3_total_changes() includes all changes 1550** from all [CREATE TRIGGER | trigger] contexts and changes made by 1551** [foreign key actions]. However, 1552** the count does not include changes used to implement [REPLACE] constraints, 1553** do rollbacks or ABORT processing, or [DROP TABLE] processing. The 1554** count does not include rows of views that fire an [INSTEAD OF trigger], 1555** though if the INSTEAD OF trigger makes changes of its own, those changes 1556** are counted.)^ 1557** ^The sqlite3_total_changes() function counts the changes as soon as 1558** the statement that makes them is completed (when the statement handle 1559** is passed to [sqlite3_reset()] or [sqlite3_finalize()]). 1560** 1561** See also the [sqlite3_changes()] interface, the 1562** [count_changes pragma], and the [total_changes() SQL function]. 1563** 1564** If a separate thread makes changes on the same database connection 1565** while [sqlite3_total_changes()] is running then the value 1566** returned is unpredictable and not meaningful. 1567*/ 1568int sqlite3_total_changes(sqlite3*); 1569 1570/* 1571** CAPI3REF: Interrupt A Long-Running Query 1572** 1573** ^This function causes any pending database operation to abort and 1574** return at its earliest opportunity. This routine is typically 1575** called in response to a user action such as pressing "Cancel" 1576** or Ctrl-C where the user wants a long query operation to halt 1577** immediately. 1578** 1579** ^It is safe to call this routine from a thread different from the 1580** thread that is currently running the database operation. But it 1581** is not safe to call this routine with a [database connection] that 1582** is closed or might close before sqlite3_interrupt() returns. 1583** 1584** ^If an SQL operation is very nearly finished at the time when 1585** sqlite3_interrupt() is called, then it might not have an opportunity 1586** to be interrupted and might continue to completion. 1587** 1588** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 1589** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 1590** that is inside an explicit transaction, then the entire transaction 1591** will be rolled back automatically. 1592** 1593** ^The sqlite3_interrupt(D) call is in effect until all currently running 1594** SQL statements on [database connection] D complete. ^Any new SQL statements 1595** that are started after the sqlite3_interrupt() call and before the 1596** running statements reaches zero are interrupted as if they had been 1597** running prior to the sqlite3_interrupt() call. ^New SQL statements 1598** that are started after the running statement count reaches zero are 1599** not effected by the sqlite3_interrupt(). 1600** ^A call to sqlite3_interrupt(D) that occurs when there are no running 1601** SQL statements is a no-op and has no effect on SQL statements 1602** that are started after the sqlite3_interrupt() call returns. 1603** 1604** If the database connection closes while [sqlite3_interrupt()] 1605** is running then bad things will likely happen. 1606*/ 1607void sqlite3_interrupt(sqlite3*); 1608 1609/* 1610** CAPI3REF: Determine If An SQL Statement Is Complete 1611** 1612** These routines are useful during command-line input to determine if the 1613** currently entered text seems to form a complete SQL statement or 1614** if additional input is needed before sending the text into 1615** SQLite for parsing. ^These routines return 1 if the input string 1616** appears to be a complete SQL statement. ^A statement is judged to be 1617** complete if it ends with a semicolon token and is not a prefix of a 1618** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 1619** string literals or quoted identifier names or comments are not 1620** independent tokens (they are part of the token in which they are 1621** embedded) and thus do not count as a statement terminator. ^Whitespace 1622** and comments that follow the final semicolon are ignored. 1623** 1624** ^These routines return 0 if the statement is incomplete. ^If a 1625** memory allocation fails, then SQLITE_NOMEM is returned. 1626** 1627** ^These routines do not parse the SQL statements thus 1628** will not detect syntactically incorrect SQL. 1629** 1630** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 1631** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 1632** automatically by sqlite3_complete16(). If that initialization fails, 1633** then the return value from sqlite3_complete16() will be non-zero 1634** regardless of whether or not the input SQL is complete.)^ 1635** 1636** The input to [sqlite3_complete()] must be a zero-terminated 1637** UTF-8 string. 1638** 1639** The input to [sqlite3_complete16()] must be a zero-terminated 1640** UTF-16 string in native byte order. 1641*/ 1642int sqlite3_complete(const char *sql); 1643int sqlite3_complete16(const void *sql); 1644 1645/* 1646** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 1647** 1648** ^This routine sets a callback function that might be invoked whenever 1649** an attempt is made to open a database table that another thread 1650** or process has locked. 1651** 1652** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] 1653** is returned immediately upon encountering the lock. ^If the busy callback 1654** is not NULL, then the callback might be invoked with two arguments. 1655** 1656** ^The first argument to the busy handler is a copy of the void* pointer which 1657** is the third argument to sqlite3_busy_handler(). ^The second argument to 1658** the busy handler callback is the number of times that the busy handler has 1659** been invoked for this locking event. ^If the 1660** busy callback returns 0, then no additional attempts are made to 1661** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned. 1662** ^If the callback returns non-zero, then another attempt 1663** is made to open the database for reading and the cycle repeats. 1664** 1665** The presence of a busy handler does not guarantee that it will be invoked 1666** when there is lock contention. ^If SQLite determines that invoking the busy 1667** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 1668** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler. 1669** Consider a scenario where one process is holding a read lock that 1670** it is trying to promote to a reserved lock and 1671** a second process is holding a reserved lock that it is trying 1672** to promote to an exclusive lock. The first process cannot proceed 1673** because it is blocked by the second and the second process cannot 1674** proceed because it is blocked by the first. If both processes 1675** invoke the busy handlers, neither will make any progress. Therefore, 1676** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 1677** will induce the first process to release its read lock and allow 1678** the second process to proceed. 1679** 1680** ^The default busy callback is NULL. 1681** 1682** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED] 1683** when SQLite is in the middle of a large transaction where all the 1684** changes will not fit into the in-memory cache. SQLite will 1685** already hold a RESERVED lock on the database file, but it needs 1686** to promote this lock to EXCLUSIVE so that it can spill cache 1687** pages into the database file without harm to concurrent 1688** readers. ^If it is unable to promote the lock, then the in-memory 1689** cache will be left in an inconsistent state and so the error 1690** code is promoted from the relatively benign [SQLITE_BUSY] to 1691** the more severe [SQLITE_IOERR_BLOCKED]. ^This error code promotion 1692** forces an automatic rollback of the changes. See the 1693** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError"> 1694** CorruptionFollowingBusyError</a> wiki page for a discussion of why 1695** this is important. 1696** 1697** ^(There can only be a single busy handler defined for each 1698** [database connection]. Setting a new busy handler clears any 1699** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 1700** will also set or clear the busy handler. 1701** 1702** The busy callback should not take any actions which modify the 1703** database connection that invoked the busy handler. Any such actions 1704** result in undefined behavior. 1705** 1706** A busy handler must not close the database connection 1707** or [prepared statement] that invoked the busy handler. 1708*/ 1709int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*); 1710 1711/* 1712** CAPI3REF: Set A Busy Timeout 1713** 1714** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 1715** for a specified amount of time when a table is locked. ^The handler 1716** will sleep multiple times until at least "ms" milliseconds of sleeping 1717** have accumulated. ^After at least "ms" milliseconds of sleeping, 1718** the handler returns 0 which causes [sqlite3_step()] to return 1719** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]. 1720** 1721** ^Calling this routine with an argument less than or equal to zero 1722** turns off all busy handlers. 1723** 1724** ^(There can only be a single busy handler for a particular 1725** [database connection] any any given moment. If another busy handler 1726** was defined (using [sqlite3_busy_handler()]) prior to calling 1727** this routine, that other busy handler is cleared.)^ 1728*/ 1729int sqlite3_busy_timeout(sqlite3*, int ms); 1730 1731/* 1732** CAPI3REF: Convenience Routines For Running Queries 1733** 1734** Definition: A <b>result table</b> is memory data structure created by the 1735** [sqlite3_get_table()] interface. A result table records the 1736** complete query results from one or more queries. 1737** 1738** The table conceptually has a number of rows and columns. But 1739** these numbers are not part of the result table itself. These 1740** numbers are obtained separately. Let N be the number of rows 1741** and M be the number of columns. 1742** 1743** A result table is an array of pointers to zero-terminated UTF-8 strings. 1744** There are (N+1)*M elements in the array. The first M pointers point 1745** to zero-terminated strings that contain the names of the columns. 1746** The remaining entries all point to query results. NULL values result 1747** in NULL pointers. All other values are in their UTF-8 zero-terminated 1748** string representation as returned by [sqlite3_column_text()]. 1749** 1750** A result table might consist of one or more memory allocations. 1751** It is not safe to pass a result table directly to [sqlite3_free()]. 1752** A result table should be deallocated using [sqlite3_free_table()]. 1753** 1754** As an example of the result table format, suppose a query result 1755** is as follows: 1756** 1757** <blockquote><pre> 1758** Name | Age 1759** ----------------------- 1760** Alice | 43 1761** Bob | 28 1762** Cindy | 21 1763** </pre></blockquote> 1764** 1765** There are two column (M==2) and three rows (N==3). Thus the 1766** result table has 8 entries. Suppose the result table is stored 1767** in an array names azResult. Then azResult holds this content: 1768** 1769** <blockquote><pre> 1770** azResult[0] = "Name"; 1771** azResult[1] = "Age"; 1772** azResult[2] = "Alice"; 1773** azResult[3] = "43"; 1774** azResult[4] = "Bob"; 1775** azResult[5] = "28"; 1776** azResult[6] = "Cindy"; 1777** azResult[7] = "21"; 1778** </pre></blockquote> 1779** 1780** ^The sqlite3_get_table() function evaluates one or more 1781** semicolon-separated SQL statements in the zero-terminated UTF-8 1782** string of its 2nd parameter and returns a result table to the 1783** pointer given in its 3rd parameter. 1784** 1785** After the application has finished with the result from sqlite3_get_table(), 1786** it should pass the result table pointer to sqlite3_free_table() in order to 1787** release the memory that was malloced. Because of the way the 1788** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 1789** function must not try to call [sqlite3_free()] directly. Only 1790** [sqlite3_free_table()] is able to release the memory properly and safely. 1791** 1792** ^(The sqlite3_get_table() interface is implemented as a wrapper around 1793** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 1794** to any internal data structures of SQLite. It uses only the public 1795** interface defined here. As a consequence, errors that occur in the 1796** wrapper layer outside of the internal [sqlite3_exec()] call are not 1797** reflected in subsequent calls to [sqlite3_errcode()] or 1798** [sqlite3_errmsg()].)^ 1799*/ 1800int sqlite3_get_table( 1801 sqlite3 *db, /* An open database */ 1802 const char *zSql, /* SQL to be evaluated */ 1803 char ***pazResult, /* Results of the query */ 1804 int *pnRow, /* Number of result rows written here */ 1805 int *pnColumn, /* Number of result columns written here */ 1806 char **pzErrmsg /* Error msg written here */ 1807); 1808void sqlite3_free_table(char **result); 1809 1810/* 1811** CAPI3REF: Formatted String Printing Functions 1812** 1813** These routines are work-alikes of the "printf()" family of functions 1814** from the standard C library. 1815** 1816** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 1817** results into memory obtained from [sqlite3_malloc()]. 1818** The strings returned by these two routines should be 1819** released by [sqlite3_free()]. ^Both routines return a 1820** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 1821** memory to hold the resulting string. 1822** 1823** ^(In sqlite3_snprintf() routine is similar to "snprintf()" from 1824** the standard C library. The result is written into the 1825** buffer supplied as the second parameter whose size is given by 1826** the first parameter. Note that the order of the 1827** first two parameters is reversed from snprintf().)^ This is an 1828** historical accident that cannot be fixed without breaking 1829** backwards compatibility. ^(Note also that sqlite3_snprintf() 1830** returns a pointer to its buffer instead of the number of 1831** characters actually written into the buffer.)^ We admit that 1832** the number of characters written would be a more useful return 1833** value but we cannot change the implementation of sqlite3_snprintf() 1834** now without breaking compatibility. 1835** 1836** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 1837** guarantees that the buffer is always zero-terminated. ^The first 1838** parameter "n" is the total size of the buffer, including space for 1839** the zero terminator. So the longest string that can be completely 1840** written will be n-1 characters. 1841** 1842** These routines all implement some additional formatting 1843** options that are useful for constructing SQL statements. 1844** All of the usual printf() formatting options apply. In addition, there 1845** is are "%q", "%Q", and "%z" options. 1846** 1847** ^(The %q option works like %s in that it substitutes a null-terminated 1848** string from the argument list. But %q also doubles every '\'' character. 1849** %q is designed for use inside a string literal.)^ By doubling each '\'' 1850** character it escapes that character and allows it to be inserted into 1851** the string. 1852** 1853** For example, assume the string variable zText contains text as follows: 1854** 1855** <blockquote><pre> 1856** char *zText = "It's a happy day!"; 1857** </pre></blockquote> 1858** 1859** One can use this text in an SQL statement as follows: 1860** 1861** <blockquote><pre> 1862** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 1863** sqlite3_exec(db, zSQL, 0, 0, 0); 1864** sqlite3_free(zSQL); 1865** </pre></blockquote> 1866** 1867** Because the %q format string is used, the '\'' character in zText 1868** is escaped and the SQL generated is as follows: 1869** 1870** <blockquote><pre> 1871** INSERT INTO table1 VALUES('It''s a happy day!') 1872** </pre></blockquote> 1873** 1874** This is correct. Had we used %s instead of %q, the generated SQL 1875** would have looked like this: 1876** 1877** <blockquote><pre> 1878** INSERT INTO table1 VALUES('It's a happy day!'); 1879** </pre></blockquote> 1880** 1881** This second example is an SQL syntax error. As a general rule you should 1882** always use %q instead of %s when inserting text into a string literal. 1883** 1884** ^(The %Q option works like %q except it also adds single quotes around 1885** the outside of the total string. Additionally, if the parameter in the 1886** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 1887** single quotes).)^ So, for example, one could say: 1888** 1889** <blockquote><pre> 1890** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 1891** sqlite3_exec(db, zSQL, 0, 0, 0); 1892** sqlite3_free(zSQL); 1893** </pre></blockquote> 1894** 1895** The code above will render a correct SQL statement in the zSQL 1896** variable even if the zText variable is a NULL pointer. 1897** 1898** ^(The "%z" formatting option works like "%s" but with the 1899** addition that after the string has been read and copied into 1900** the result, [sqlite3_free()] is called on the input string.)^ 1901*/ 1902char *sqlite3_mprintf(const char*,...); 1903char *sqlite3_vmprintf(const char*, va_list); 1904char *sqlite3_snprintf(int,char*,const char*, ...); 1905 1906/* 1907** CAPI3REF: Memory Allocation Subsystem 1908** 1909** The SQLite core uses these three routines for all of its own 1910** internal memory allocation needs. "Core" in the previous sentence 1911** does not include operating-system specific VFS implementation. The 1912** Windows VFS uses native malloc() and free() for some operations. 1913** 1914** ^The sqlite3_malloc() routine returns a pointer to a block 1915** of memory at least N bytes in length, where N is the parameter. 1916** ^If sqlite3_malloc() is unable to obtain sufficient free 1917** memory, it returns a NULL pointer. ^If the parameter N to 1918** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 1919** a NULL pointer. 1920** 1921** ^Calling sqlite3_free() with a pointer previously returned 1922** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 1923** that it might be reused. ^The sqlite3_free() routine is 1924** a no-op if is called with a NULL pointer. Passing a NULL pointer 1925** to sqlite3_free() is harmless. After being freed, memory 1926** should neither be read nor written. Even reading previously freed 1927** memory might result in a segmentation fault or other severe error. 1928** Memory corruption, a segmentation fault, or other severe error 1929** might result if sqlite3_free() is called with a non-NULL pointer that 1930** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 1931** 1932** ^(The sqlite3_realloc() interface attempts to resize a 1933** prior memory allocation to be at least N bytes, where N is the 1934** second parameter. The memory allocation to be resized is the first 1935** parameter.)^ ^ If the first parameter to sqlite3_realloc() 1936** is a NULL pointer then its behavior is identical to calling 1937** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc(). 1938** ^If the second parameter to sqlite3_realloc() is zero or 1939** negative then the behavior is exactly the same as calling 1940** sqlite3_free(P) where P is the first parameter to sqlite3_realloc(). 1941** ^sqlite3_realloc() returns a pointer to a memory allocation 1942** of at least N bytes in size or NULL if sufficient memory is unavailable. 1943** ^If M is the size of the prior allocation, then min(N,M) bytes 1944** of the prior allocation are copied into the beginning of buffer returned 1945** by sqlite3_realloc() and the prior allocation is freed. 1946** ^If sqlite3_realloc() returns NULL, then the prior allocation 1947** is not freed. 1948** 1949** ^The memory returned by sqlite3_malloc() and sqlite3_realloc() 1950** is always aligned to at least an 8 byte boundary, or to a 1951** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 1952** option is used. 1953** 1954** In SQLite version 3.5.0 and 3.5.1, it was possible to define 1955** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 1956** implementation of these routines to be omitted. That capability 1957** is no longer provided. Only built-in memory allocators can be used. 1958** 1959** The Windows OS interface layer calls 1960** the system malloc() and free() directly when converting 1961** filenames between the UTF-8 encoding used by SQLite 1962** and whatever filename encoding is used by the particular Windows 1963** installation. Memory allocation errors are detected, but 1964** they are reported back as [SQLITE_CANTOPEN] or 1965** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 1966** 1967** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 1968** must be either NULL or else pointers obtained from a prior 1969** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 1970** not yet been released. 1971** 1972** The application must not read or write any part of 1973** a block of memory after it has been released using 1974** [sqlite3_free()] or [sqlite3_realloc()]. 1975*/ 1976void *sqlite3_malloc(int); 1977void *sqlite3_realloc(void*, int); 1978void sqlite3_free(void*); 1979 1980/* 1981** CAPI3REF: Memory Allocator Statistics 1982** 1983** SQLite provides these two interfaces for reporting on the status 1984** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 1985** routines, which form the built-in memory allocation subsystem. 1986** 1987** ^The [sqlite3_memory_used()] routine returns the number of bytes 1988** of memory currently outstanding (malloced but not freed). 1989** ^The [sqlite3_memory_highwater()] routine returns the maximum 1990** value of [sqlite3_memory_used()] since the high-water mark 1991** was last reset. ^The values returned by [sqlite3_memory_used()] and 1992** [sqlite3_memory_highwater()] include any overhead 1993** added by SQLite in its implementation of [sqlite3_malloc()], 1994** but not overhead added by the any underlying system library 1995** routines that [sqlite3_malloc()] may call. 1996** 1997** ^The memory high-water mark is reset to the current value of 1998** [sqlite3_memory_used()] if and only if the parameter to 1999** [sqlite3_memory_highwater()] is true. ^The value returned 2000** by [sqlite3_memory_highwater(1)] is the high-water mark 2001** prior to the reset. 2002*/ 2003sqlite3_int64 sqlite3_memory_used(void); 2004sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2005 2006/* 2007** CAPI3REF: Pseudo-Random Number Generator 2008** 2009** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2010** select random [ROWID | ROWIDs] when inserting new records into a table that 2011** already uses the largest possible [ROWID]. The PRNG is also used for 2012** the build-in random() and randomblob() SQL functions. This interface allows 2013** applications to access the same PRNG for other purposes. 2014** 2015** ^A call to this routine stores N bytes of randomness into buffer P. 2016** 2017** ^The first time this routine is invoked (either internally or by 2018** the application) the PRNG is seeded using randomness obtained 2019** from the xRandomness method of the default [sqlite3_vfs] object. 2020** ^On all subsequent invocations, the pseudo-randomness is generated 2021** internally and without recourse to the [sqlite3_vfs] xRandomness 2022** method. 2023*/ 2024void sqlite3_randomness(int N, void *P); 2025 2026/* 2027** CAPI3REF: Compile-Time Authorization Callbacks 2028** 2029** ^This routine registers a authorizer callback with a particular 2030** [database connection], supplied in the first argument. 2031** ^The authorizer callback is invoked as SQL statements are being compiled 2032** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2033** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various 2034** points during the compilation process, as logic is being created 2035** to perform various actions, the authorizer callback is invoked to 2036** see if those actions are allowed. ^The authorizer callback should 2037** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2038** specific action but allow the SQL statement to continue to be 2039** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2040** rejected with an error. ^If the authorizer callback returns 2041** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2042** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2043** the authorizer will fail with an error message. 2044** 2045** When the callback returns [SQLITE_OK], that means the operation 2046** requested is ok. ^When the callback returns [SQLITE_DENY], the 2047** [sqlite3_prepare_v2()] or equivalent call that triggered the 2048** authorizer will fail with an error message explaining that 2049** access is denied. 2050** 2051** ^The first parameter to the authorizer callback is a copy of the third 2052** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2053** to the callback is an integer [SQLITE_COPY | action code] that specifies 2054** the particular action to be authorized. ^The third through sixth parameters 2055** to the callback are zero-terminated strings that contain additional 2056** details about the action to be authorized. 2057** 2058** ^If the action code is [SQLITE_READ] 2059** and the callback returns [SQLITE_IGNORE] then the 2060** [prepared statement] statement is constructed to substitute 2061** a NULL value in place of the table column that would have 2062** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2063** return can be used to deny an untrusted user access to individual 2064** columns of a table. 2065** ^If the action code is [SQLITE_DELETE] and the callback returns 2066** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2067** [truncate optimization] is disabled and all rows are deleted individually. 2068** 2069** An authorizer is used when [sqlite3_prepare | preparing] 2070** SQL statements from an untrusted source, to ensure that the SQL statements 2071** do not try to access data they are not allowed to see, or that they do not 2072** try to execute malicious statements that damage the database. For 2073** example, an application may allow a user to enter arbitrary 2074** SQL queries for evaluation by a database. But the application does 2075** not want the user to be able to make arbitrary changes to the 2076** database. An authorizer could then be put in place while the 2077** user-entered SQL is being [sqlite3_prepare | prepared] that 2078** disallows everything except [SELECT] statements. 2079** 2080** Applications that need to process SQL from untrusted sources 2081** might also consider lowering resource limits using [sqlite3_limit()] 2082** and limiting database size using the [max_page_count] [PRAGMA] 2083** in addition to using an authorizer. 2084** 2085** ^(Only a single authorizer can be in place on a database connection 2086** at a time. Each call to sqlite3_set_authorizer overrides the 2087** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2088** The authorizer is disabled by default. 2089** 2090** The authorizer callback must not do anything that will modify 2091** the database connection that invoked the authorizer callback. 2092** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2093** database connections for the meaning of "modify" in this paragraph. 2094** 2095** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2096** statement might be re-prepared during [sqlite3_step()] due to a 2097** schema change. Hence, the application should ensure that the 2098** correct authorizer callback remains in place during the [sqlite3_step()]. 2099** 2100** ^Note that the authorizer callback is invoked only during 2101** [sqlite3_prepare()] or its variants. Authorization is not 2102** performed during statement evaluation in [sqlite3_step()], unless 2103** as stated in the previous paragraph, sqlite3_step() invokes 2104** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2105*/ 2106int sqlite3_set_authorizer( 2107 sqlite3*, 2108 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2109 void *pUserData 2110); 2111 2112/* 2113** CAPI3REF: Authorizer Return Codes 2114** 2115** The [sqlite3_set_authorizer | authorizer callback function] must 2116** return either [SQLITE_OK] or one of these two constants in order 2117** to signal SQLite whether or not the action is permitted. See the 2118** [sqlite3_set_authorizer | authorizer documentation] for additional 2119** information. 2120*/ 2121#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2122#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2123 2124/* 2125** CAPI3REF: Authorizer Action Codes 2126** 2127** The [sqlite3_set_authorizer()] interface registers a callback function 2128** that is invoked to authorize certain SQL statement actions. The 2129** second parameter to the callback is an integer code that specifies 2130** what action is being authorized. These are the integer action codes that 2131** the authorizer callback may be passed. 2132** 2133** These action code values signify what kind of operation is to be 2134** authorized. The 3rd and 4th parameters to the authorization 2135** callback function will be parameters or NULL depending on which of these 2136** codes is used as the second parameter. ^(The 5th parameter to the 2137** authorizer callback is the name of the database ("main", "temp", 2138** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2139** is the name of the inner-most trigger or view that is responsible for 2140** the access attempt or NULL if this access attempt is directly from 2141** top-level SQL code. 2142*/ 2143/******************************************* 3rd ************ 4th ***********/ 2144#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2145#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2146#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2147#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2148#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2149#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2150#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2151#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2152#define SQLITE_DELETE 9 /* Table Name NULL */ 2153#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2154#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2155#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2156#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2157#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2158#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2159#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2160#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2161#define SQLITE_INSERT 18 /* Table Name NULL */ 2162#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2163#define SQLITE_READ 20 /* Table Name Column Name */ 2164#define SQLITE_SELECT 21 /* NULL NULL */ 2165#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2166#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2167#define SQLITE_ATTACH 24 /* Filename NULL */ 2168#define SQLITE_DETACH 25 /* Database Name NULL */ 2169#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2170#define SQLITE_REINDEX 27 /* Index Name NULL */ 2171#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2172#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2173#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2174#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2175#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2176#define SQLITE_COPY 0 /* No longer used */ 2177 2178/* 2179** CAPI3REF: Tracing And Profiling Functions 2180** 2181** These routines register callback functions that can be used for 2182** tracing and profiling the execution of SQL statements. 2183** 2184** ^The callback function registered by sqlite3_trace() is invoked at 2185** various times when an SQL statement is being run by [sqlite3_step()]. 2186** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2187** SQL statement text as the statement first begins executing. 2188** ^(Additional sqlite3_trace() callbacks might occur 2189** as each triggered subprogram is entered. The callbacks for triggers 2190** contain a UTF-8 SQL comment that identifies the trigger.)^ 2191** 2192** ^The callback function registered by sqlite3_profile() is invoked 2193** as each SQL statement finishes. ^The profile callback contains 2194** the original statement text and an estimate of wall-clock time 2195** of how long that statement took to run. ^The profile callback 2196** time is in units of nanoseconds, however the current implementation 2197** is only capable of millisecond resolution so the six least significant 2198** digits in the time are meaningless. Future versions of SQLite 2199** might provide greater resolution on the profiler callback. The 2200** sqlite3_profile() function is considered experimental and is 2201** subject to change in future versions of SQLite. 2202*/ 2203void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*); 2204SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*, 2205 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2206 2207/* 2208** CAPI3REF: Query Progress Callbacks 2209** 2210** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 2211** function X to be invoked periodically during long running calls to 2212** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 2213** database connection D. An example use for this 2214** interface is to keep a GUI updated during a large query. 2215** 2216** ^The parameter P is passed through as the only parameter to the 2217** callback function X. ^The parameter N is the number of 2218** [virtual machine instructions] that are evaluated between successive 2219** invocations of the callback X. 2220** 2221** ^Only a single progress handler may be defined at one time per 2222** [database connection]; setting a new progress handler cancels the 2223** old one. ^Setting parameter X to NULL disables the progress handler. 2224** ^The progress handler is also disabled by setting N to a value less 2225** than 1. 2226** 2227** ^If the progress callback returns non-zero, the operation is 2228** interrupted. This feature can be used to implement a 2229** "Cancel" button on a GUI progress dialog box. 2230** 2231** The progress handler callback must not do anything that will modify 2232** the database connection that invoked the progress handler. 2233** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2234** database connections for the meaning of "modify" in this paragraph. 2235** 2236*/ 2237void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 2238 2239/* 2240** CAPI3REF: Opening A New Database Connection 2241** 2242** ^These routines open an SQLite database file whose name is given by the 2243** filename argument. ^The filename argument is interpreted as UTF-8 for 2244** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 2245** order for sqlite3_open16(). ^(A [database connection] handle is usually 2246** returned in *ppDb, even if an error occurs. The only exception is that 2247** if SQLite is unable to allocate memory to hold the [sqlite3] object, 2248** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 2249** object.)^ ^(If the database is opened (and/or created) successfully, then 2250** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 2251** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 2252** an English language description of the error following a failure of any 2253** of the sqlite3_open() routines. 2254** 2255** ^The default encoding for the database will be UTF-8 if 2256** sqlite3_open() or sqlite3_open_v2() is called and 2257** UTF-16 in the native byte order if sqlite3_open16() is used. 2258** 2259** Whether or not an error occurs when it is opened, resources 2260** associated with the [database connection] handle should be released by 2261** passing it to [sqlite3_close()] when it is no longer required. 2262** 2263** The sqlite3_open_v2() interface works like sqlite3_open() 2264** except that it accepts two additional parameters for additional control 2265** over the new database connection. ^(The flags parameter to 2266** sqlite3_open_v2() can take one of 2267** the following three values, optionally combined with the 2268** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 2269** and/or [SQLITE_OPEN_PRIVATECACHE] flags:)^ 2270** 2271** <dl> 2272** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 2273** <dd>The database is opened in read-only mode. If the database does not 2274** already exist, an error is returned.</dd>)^ 2275** 2276** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 2277** <dd>The database is opened for reading and writing if possible, or reading 2278** only if the file is write protected by the operating system. In either 2279** case the database must already exist, otherwise an error is returned.</dd>)^ 2280** 2281** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 2282** <dd>The database is opened for reading and writing, and is creates it if 2283** it does not already exist. This is the behavior that is always used for 2284** sqlite3_open() and sqlite3_open16().</dd>)^ 2285** </dl> 2286** 2287** If the 3rd parameter to sqlite3_open_v2() is not one of the 2288** combinations shown above or one of the combinations shown above combined 2289** with the [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], 2290** [SQLITE_OPEN_SHAREDCACHE] and/or [SQLITE_OPEN_PRIVATECACHE] flags, 2291** then the behavior is undefined. 2292** 2293** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 2294** opens in the multi-thread [threading mode] as long as the single-thread 2295** mode has not been set at compile-time or start-time. ^If the 2296** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 2297** in the serialized [threading mode] unless single-thread was 2298** previously selected at compile-time or start-time. 2299** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 2300** eligible to use [shared cache mode], regardless of whether or not shared 2301** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 2302** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 2303** participate in [shared cache mode] even if it is enabled. 2304** 2305** ^If the filename is ":memory:", then a private, temporary in-memory database 2306** is created for the connection. ^This in-memory database will vanish when 2307** the database connection is closed. Future versions of SQLite might 2308** make use of additional special filenames that begin with the ":" character. 2309** It is recommended that when a database filename actually does begin with 2310** a ":" character you should prefix the filename with a pathname such as 2311** "./" to avoid ambiguity. 2312** 2313** ^If the filename is an empty string, then a private, temporary 2314** on-disk database will be created. ^This private database will be 2315** automatically deleted as soon as the database connection is closed. 2316** 2317** ^The fourth parameter to sqlite3_open_v2() is the name of the 2318** [sqlite3_vfs] object that defines the operating system interface that 2319** the new database connection should use. ^If the fourth parameter is 2320** a NULL pointer then the default [sqlite3_vfs] object is used. 2321** 2322** <b>Note to Windows users:</b> The encoding used for the filename argument 2323** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 2324** codepage is currently defined. Filenames containing international 2325** characters must be converted to UTF-8 prior to passing them into 2326** sqlite3_open() or sqlite3_open_v2(). 2327*/ 2328int sqlite3_open( 2329 const char *filename, /* Database filename (UTF-8) */ 2330 sqlite3 **ppDb /* OUT: SQLite db handle */ 2331); 2332int sqlite3_open16( 2333 const void *filename, /* Database filename (UTF-16) */ 2334 sqlite3 **ppDb /* OUT: SQLite db handle */ 2335); 2336int sqlite3_open_v2( 2337 const char *filename, /* Database filename (UTF-8) */ 2338 sqlite3 **ppDb, /* OUT: SQLite db handle */ 2339 int flags, /* Flags */ 2340 const char *zVfs /* Name of VFS module to use */ 2341); 2342 2343/* 2344** CAPI3REF: Error Codes And Messages 2345** 2346** ^The sqlite3_errcode() interface returns the numeric [result code] or 2347** [extended result code] for the most recent failed sqlite3_* API call 2348** associated with a [database connection]. If a prior API call failed 2349** but the most recent API call succeeded, the return value from 2350** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode() 2351** interface is the same except that it always returns the 2352** [extended result code] even when extended result codes are 2353** disabled. 2354** 2355** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 2356** text that describes the error, as either UTF-8 or UTF-16 respectively. 2357** ^(Memory to hold the error message string is managed internally. 2358** The application does not need to worry about freeing the result. 2359** However, the error string might be overwritten or deallocated by 2360** subsequent calls to other SQLite interface functions.)^ 2361** 2362** When the serialized [threading mode] is in use, it might be the 2363** case that a second error occurs on a separate thread in between 2364** the time of the first error and the call to these interfaces. 2365** When that happens, the second error will be reported since these 2366** interfaces always report the most recent result. To avoid 2367** this, each thread can obtain exclusive use of the [database connection] D 2368** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 2369** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 2370** all calls to the interfaces listed here are completed. 2371** 2372** If an interface fails with SQLITE_MISUSE, that means the interface 2373** was invoked incorrectly by the application. In that case, the 2374** error code and message may or may not be set. 2375*/ 2376int sqlite3_errcode(sqlite3 *db); 2377int sqlite3_extended_errcode(sqlite3 *db); 2378const char *sqlite3_errmsg(sqlite3*); 2379const void *sqlite3_errmsg16(sqlite3*); 2380 2381/* 2382** CAPI3REF: SQL Statement Object 2383** KEYWORDS: {prepared statement} {prepared statements} 2384** 2385** An instance of this object represents a single SQL statement. 2386** This object is variously known as a "prepared statement" or a 2387** "compiled SQL statement" or simply as a "statement". 2388** 2389** The life of a statement object goes something like this: 2390** 2391** <ol> 2392** <li> Create the object using [sqlite3_prepare_v2()] or a related 2393** function. 2394** <li> Bind values to [host parameters] using the sqlite3_bind_*() 2395** interfaces. 2396** <li> Run the SQL by calling [sqlite3_step()] one or more times. 2397** <li> Reset the statement using [sqlite3_reset()] then go back 2398** to step 2. Do this zero or more times. 2399** <li> Destroy the object using [sqlite3_finalize()]. 2400** </ol> 2401** 2402** Refer to documentation on individual methods above for additional 2403** information. 2404*/ 2405typedef struct sqlite3_stmt sqlite3_stmt; 2406 2407/* 2408** CAPI3REF: Run-time Limits 2409** 2410** ^(This interface allows the size of various constructs to be limited 2411** on a connection by connection basis. The first parameter is the 2412** [database connection] whose limit is to be set or queried. The 2413** second parameter is one of the [limit categories] that define a 2414** class of constructs to be size limited. The third parameter is the 2415** new limit for that construct.)^ 2416** 2417** ^If the new limit is a negative number, the limit is unchanged. 2418** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 2419** [limits | hard upper bound] 2420** set at compile-time by a C preprocessor macro called 2421** [limits | SQLITE_MAX_<i>NAME</i>]. 2422** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 2423** ^Attempts to increase a limit above its hard upper bound are 2424** silently truncated to the hard upper bound. 2425** 2426** ^Regardless of whether or not the limit was changed, the 2427** [sqlite3_limit()] interface returns the prior value of the limit. 2428** ^Hence, to find the current value of a limit without changing it, 2429** simply invoke this interface with the third parameter set to -1. 2430** 2431** Run-time limits are intended for use in applications that manage 2432** both their own internal database and also databases that are controlled 2433** by untrusted external sources. An example application might be a 2434** web browser that has its own databases for storing history and 2435** separate databases controlled by JavaScript applications downloaded 2436** off the Internet. The internal databases can be given the 2437** large, default limits. Databases managed by external sources can 2438** be given much smaller limits designed to prevent a denial of service 2439** attack. Developers might also want to use the [sqlite3_set_authorizer()] 2440** interface to further control untrusted SQL. The size of the database 2441** created by an untrusted script can be contained using the 2442** [max_page_count] [PRAGMA]. 2443** 2444** New run-time limit categories may be added in future releases. 2445*/ 2446int sqlite3_limit(sqlite3*, int id, int newVal); 2447 2448/* 2449** CAPI3REF: Run-Time Limit Categories 2450** KEYWORDS: {limit category} {*limit categories} 2451** 2452** These constants define various performance limits 2453** that can be lowered at run-time using [sqlite3_limit()]. 2454** The synopsis of the meanings of the various limits is shown below. 2455** Additional information is available at [limits | Limits in SQLite]. 2456** 2457** <dl> 2458** ^(<dt>SQLITE_LIMIT_LENGTH</dt> 2459** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 2460** 2461** ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 2462** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 2463** 2464** ^(<dt>SQLITE_LIMIT_COLUMN</dt> 2465** <dd>The maximum number of columns in a table definition or in the 2466** result set of a [SELECT] or the maximum number of columns in an index 2467** or in an ORDER BY or GROUP BY clause.</dd>)^ 2468** 2469** ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 2470** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 2471** 2472** ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 2473** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 2474** 2475** ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 2476** <dd>The maximum number of instructions in a virtual machine program 2477** used to implement an SQL statement. This limit is not currently 2478** enforced, though that might be added in some future release of 2479** SQLite.</dd>)^ 2480** 2481** ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 2482** <dd>The maximum number of arguments on a function.</dd>)^ 2483** 2484** ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 2485** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 2486** 2487** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 2488** <dd>The maximum length of the pattern argument to the [LIKE] or 2489** [GLOB] operators.</dd>)^ 2490** 2491** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 2492** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 2493** 2494** ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 2495** <dd>The maximum depth of recursion for triggers.</dd>)^ 2496** </dl> 2497*/ 2498#define SQLITE_LIMIT_LENGTH 0 2499#define SQLITE_LIMIT_SQL_LENGTH 1 2500#define SQLITE_LIMIT_COLUMN 2 2501#define SQLITE_LIMIT_EXPR_DEPTH 3 2502#define SQLITE_LIMIT_COMPOUND_SELECT 4 2503#define SQLITE_LIMIT_VDBE_OP 5 2504#define SQLITE_LIMIT_FUNCTION_ARG 6 2505#define SQLITE_LIMIT_ATTACHED 7 2506#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 2507#define SQLITE_LIMIT_VARIABLE_NUMBER 9 2508#define SQLITE_LIMIT_TRIGGER_DEPTH 10 2509 2510/* 2511** CAPI3REF: Compiling An SQL Statement 2512** KEYWORDS: {SQL statement compiler} 2513** 2514** To execute an SQL query, it must first be compiled into a byte-code 2515** program using one of these routines. 2516** 2517** The first argument, "db", is a [database connection] obtained from a 2518** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 2519** [sqlite3_open16()]. The database connection must not have been closed. 2520** 2521** The second argument, "zSql", is the statement to be compiled, encoded 2522** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() 2523** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() 2524** use UTF-16. 2525** 2526** ^If the nByte argument is less than zero, then zSql is read up to the 2527** first zero terminator. ^If nByte is non-negative, then it is the maximum 2528** number of bytes read from zSql. ^When nByte is non-negative, the 2529** zSql string ends at either the first '\000' or '\u0000' character or 2530** the nByte-th byte, whichever comes first. If the caller knows 2531** that the supplied string is nul-terminated, then there is a small 2532** performance advantage to be gained by passing an nByte parameter that 2533** is equal to the number of bytes in the input string <i>including</i> 2534** the nul-terminator bytes. 2535** 2536** ^If pzTail is not NULL then *pzTail is made to point to the first byte 2537** past the end of the first SQL statement in zSql. These routines only 2538** compile the first statement in zSql, so *pzTail is left pointing to 2539** what remains uncompiled. 2540** 2541** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 2542** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 2543** to NULL. ^If the input text contains no SQL (if the input is an empty 2544** string or a comment) then *ppStmt is set to NULL. 2545** The calling procedure is responsible for deleting the compiled 2546** SQL statement using [sqlite3_finalize()] after it has finished with it. 2547** ppStmt may not be NULL. 2548** 2549** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 2550** otherwise an [error code] is returned. 2551** 2552** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are 2553** recommended for all new programs. The two older interfaces are retained 2554** for backwards compatibility, but their use is discouraged. 2555** ^In the "v2" interfaces, the prepared statement 2556** that is returned (the [sqlite3_stmt] object) contains a copy of the 2557** original SQL text. This causes the [sqlite3_step()] interface to 2558** behave differently in three ways: 2559** 2560** <ol> 2561** <li> 2562** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 2563** always used to do, [sqlite3_step()] will automatically recompile the SQL 2564** statement and try to run it again. 2565** </li> 2566** 2567** <li> 2568** ^When an error occurs, [sqlite3_step()] will return one of the detailed 2569** [error codes] or [extended error codes]. ^The legacy behavior was that 2570** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 2571** and the application would have to make a second call to [sqlite3_reset()] 2572** in order to find the underlying cause of the problem. With the "v2" prepare 2573** interfaces, the underlying reason for the error is returned immediately. 2574** </li> 2575** 2576** <li> 2577** ^If the specific value bound to [parameter | host parameter] in the 2578** WHERE clause might influence the choice of query plan for a statement, 2579** then the statement will be automatically recompiled, as if there had been 2580** a schema change, on the first [sqlite3_step()] call following any change 2581** to the [sqlite3_bind_text | bindings] of that [parameter]. 2582** ^The specific value of WHERE-clause [parameter] might influence the 2583** choice of query plan if the parameter is the left-hand side of a [LIKE] 2584** or [GLOB] operator or if the parameter is compared to an indexed column 2585** and the [SQLITE_ENABLE_STAT2] compile-time option is enabled. 2586** the 2587** </li> 2588** </ol> 2589*/ 2590int sqlite3_prepare( 2591 sqlite3 *db, /* Database handle */ 2592 const char *zSql, /* SQL statement, UTF-8 encoded */ 2593 int nByte, /* Maximum length of zSql in bytes. */ 2594 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2595 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2596); 2597int sqlite3_prepare_v2( 2598 sqlite3 *db, /* Database handle */ 2599 const char *zSql, /* SQL statement, UTF-8 encoded */ 2600 int nByte, /* Maximum length of zSql in bytes. */ 2601 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2602 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2603); 2604int sqlite3_prepare16( 2605 sqlite3 *db, /* Database handle */ 2606 const void *zSql, /* SQL statement, UTF-16 encoded */ 2607 int nByte, /* Maximum length of zSql in bytes. */ 2608 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2609 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2610); 2611int sqlite3_prepare16_v2( 2612 sqlite3 *db, /* Database handle */ 2613 const void *zSql, /* SQL statement, UTF-16 encoded */ 2614 int nByte, /* Maximum length of zSql in bytes. */ 2615 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2616 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2617); 2618 2619/* 2620** CAPI3REF: Retrieving Statement SQL 2621** 2622** ^This interface can be used to retrieve a saved copy of the original 2623** SQL text used to create a [prepared statement] if that statement was 2624** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. 2625*/ 2626const char *sqlite3_sql(sqlite3_stmt *pStmt); 2627 2628/* 2629** CAPI3REF: Dynamically Typed Value Object 2630** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 2631** 2632** SQLite uses the sqlite3_value object to represent all values 2633** that can be stored in a database table. SQLite uses dynamic typing 2634** for the values it stores. ^Values stored in sqlite3_value objects 2635** can be integers, floating point values, strings, BLOBs, or NULL. 2636** 2637** An sqlite3_value object may be either "protected" or "unprotected". 2638** Some interfaces require a protected sqlite3_value. Other interfaces 2639** will accept either a protected or an unprotected sqlite3_value. 2640** Every interface that accepts sqlite3_value arguments specifies 2641** whether or not it requires a protected sqlite3_value. 2642** 2643** The terms "protected" and "unprotected" refer to whether or not 2644** a mutex is held. A internal mutex is held for a protected 2645** sqlite3_value object but no mutex is held for an unprotected 2646** sqlite3_value object. If SQLite is compiled to be single-threaded 2647** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 2648** or if SQLite is run in one of reduced mutex modes 2649** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 2650** then there is no distinction between protected and unprotected 2651** sqlite3_value objects and they can be used interchangeably. However, 2652** for maximum code portability it is recommended that applications 2653** still make the distinction between protected and unprotected 2654** sqlite3_value objects even when not strictly required. 2655** 2656** ^The sqlite3_value objects that are passed as parameters into the 2657** implementation of [application-defined SQL functions] are protected. 2658** ^The sqlite3_value object returned by 2659** [sqlite3_column_value()] is unprotected. 2660** Unprotected sqlite3_value objects may only be used with 2661** [sqlite3_result_value()] and [sqlite3_bind_value()]. 2662** The [sqlite3_value_blob | sqlite3_value_type()] family of 2663** interfaces require protected sqlite3_value objects. 2664*/ 2665typedef struct Mem sqlite3_value; 2666 2667/* 2668** CAPI3REF: SQL Function Context Object 2669** 2670** The context in which an SQL function executes is stored in an 2671** sqlite3_context object. ^A pointer to an sqlite3_context object 2672** is always first parameter to [application-defined SQL functions]. 2673** The application-defined SQL function implementation will pass this 2674** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 2675** [sqlite3_aggregate_context()], [sqlite3_user_data()], 2676** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 2677** and/or [sqlite3_set_auxdata()]. 2678*/ 2679typedef struct sqlite3_context sqlite3_context; 2680 2681/* 2682** CAPI3REF: Binding Values To Prepared Statements 2683** KEYWORDS: {host parameter} {host parameters} {host parameter name} 2684** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 2685** 2686** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 2687** literals may be replaced by a [parameter] that matches one of following 2688** templates: 2689** 2690** <ul> 2691** <li> ? 2692** <li> ?NNN 2693** <li> :VVV 2694** <li> @VVV 2695** <li> $VVV 2696** </ul> 2697** 2698** In the templates above, NNN represents an integer literal, 2699** and VVV represents an alphanumeric identifier.)^ ^The values of these 2700** parameters (also called "host parameter names" or "SQL parameters") 2701** can be set using the sqlite3_bind_*() routines defined here. 2702** 2703** ^The first argument to the sqlite3_bind_*() routines is always 2704** a pointer to the [sqlite3_stmt] object returned from 2705** [sqlite3_prepare_v2()] or its variants. 2706** 2707** ^The second argument is the index of the SQL parameter to be set. 2708** ^The leftmost SQL parameter has an index of 1. ^When the same named 2709** SQL parameter is used more than once, second and subsequent 2710** occurrences have the same index as the first occurrence. 2711** ^The index for named parameters can be looked up using the 2712** [sqlite3_bind_parameter_index()] API if desired. ^The index 2713** for "?NNN" parameters is the value of NNN. 2714** ^The NNN value must be between 1 and the [sqlite3_limit()] 2715** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 2716** 2717** ^The third argument is the value to bind to the parameter. 2718** 2719** ^(In those routines that have a fourth argument, its value is the 2720** number of bytes in the parameter. To be clear: the value is the 2721** number of <u>bytes</u> in the value, not the number of characters.)^ 2722** ^If the fourth parameter is negative, the length of the string is 2723** the number of bytes up to the first zero terminator. 2724** 2725** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and 2726** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or 2727** string after SQLite has finished with it. ^If the fifth argument is 2728** the special value [SQLITE_STATIC], then SQLite assumes that the 2729** information is in static, unmanaged space and does not need to be freed. 2730** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 2731** SQLite makes its own private copy of the data immediately, before 2732** the sqlite3_bind_*() routine returns. 2733** 2734** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 2735** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 2736** (just an integer to hold its size) while it is being processed. 2737** Zeroblobs are intended to serve as placeholders for BLOBs whose 2738** content is later written using 2739** [sqlite3_blob_open | incremental BLOB I/O] routines. 2740** ^A negative value for the zeroblob results in a zero-length BLOB. 2741** 2742** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 2743** for the [prepared statement] or with a prepared statement for which 2744** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 2745** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 2746** routine is passed a [prepared statement] that has been finalized, the 2747** result is undefined and probably harmful. 2748** 2749** ^Bindings are not cleared by the [sqlite3_reset()] routine. 2750** ^Unbound parameters are interpreted as NULL. 2751** 2752** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 2753** [error code] if anything goes wrong. 2754** ^[SQLITE_RANGE] is returned if the parameter 2755** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 2756** 2757** See also: [sqlite3_bind_parameter_count()], 2758** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 2759*/ 2760int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 2761int sqlite3_bind_double(sqlite3_stmt*, int, double); 2762int sqlite3_bind_int(sqlite3_stmt*, int, int); 2763int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 2764int sqlite3_bind_null(sqlite3_stmt*, int); 2765int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*)); 2766int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 2767int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 2768int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 2769 2770/* 2771** CAPI3REF: Number Of SQL Parameters 2772** 2773** ^This routine can be used to find the number of [SQL parameters] 2774** in a [prepared statement]. SQL parameters are tokens of the 2775** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 2776** placeholders for values that are [sqlite3_bind_blob | bound] 2777** to the parameters at a later time. 2778** 2779** ^(This routine actually returns the index of the largest (rightmost) 2780** parameter. For all forms except ?NNN, this will correspond to the 2781** number of unique parameters. If parameters of the ?NNN form are used, 2782** there may be gaps in the list.)^ 2783** 2784** See also: [sqlite3_bind_blob|sqlite3_bind()], 2785** [sqlite3_bind_parameter_name()], and 2786** [sqlite3_bind_parameter_index()]. 2787*/ 2788int sqlite3_bind_parameter_count(sqlite3_stmt*); 2789 2790/* 2791** CAPI3REF: Name Of A Host Parameter 2792** 2793** ^The sqlite3_bind_parameter_name(P,N) interface returns 2794** the name of the N-th [SQL parameter] in the [prepared statement] P. 2795** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 2796** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 2797** respectively. 2798** In other words, the initial ":" or "$" or "@" or "?" 2799** is included as part of the name.)^ 2800** ^Parameters of the form "?" without a following integer have no name 2801** and are referred to as "nameless" or "anonymous parameters". 2802** 2803** ^The first host parameter has an index of 1, not 0. 2804** 2805** ^If the value N is out of range or if the N-th parameter is 2806** nameless, then NULL is returned. ^The returned string is 2807** always in UTF-8 encoding even if the named parameter was 2808** originally specified as UTF-16 in [sqlite3_prepare16()] or 2809** [sqlite3_prepare16_v2()]. 2810** 2811** See also: [sqlite3_bind_blob|sqlite3_bind()], 2812** [sqlite3_bind_parameter_count()], and 2813** [sqlite3_bind_parameter_index()]. 2814*/ 2815const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 2816 2817/* 2818** CAPI3REF: Index Of A Parameter With A Given Name 2819** 2820** ^Return the index of an SQL parameter given its name. ^The 2821** index value returned is suitable for use as the second 2822** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 2823** is returned if no matching parameter is found. ^The parameter 2824** name must be given in UTF-8 even if the original statement 2825** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. 2826** 2827** See also: [sqlite3_bind_blob|sqlite3_bind()], 2828** [sqlite3_bind_parameter_count()], and 2829** [sqlite3_bind_parameter_index()]. 2830*/ 2831int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 2832 2833/* 2834** CAPI3REF: Reset All Bindings On A Prepared Statement 2835** 2836** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 2837** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 2838** ^Use this routine to reset all host parameters to NULL. 2839*/ 2840int sqlite3_clear_bindings(sqlite3_stmt*); 2841 2842/* 2843** CAPI3REF: Number Of Columns In A Result Set 2844** 2845** ^Return the number of columns in the result set returned by the 2846** [prepared statement]. ^This routine returns 0 if pStmt is an SQL 2847** statement that does not return data (for example an [UPDATE]). 2848** 2849** See also: [sqlite3_data_count()] 2850*/ 2851int sqlite3_column_count(sqlite3_stmt *pStmt); 2852 2853/* 2854** CAPI3REF: Column Names In A Result Set 2855** 2856** ^These routines return the name assigned to a particular column 2857** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 2858** interface returns a pointer to a zero-terminated UTF-8 string 2859** and sqlite3_column_name16() returns a pointer to a zero-terminated 2860** UTF-16 string. ^The first parameter is the [prepared statement] 2861** that implements the [SELECT] statement. ^The second parameter is the 2862** column number. ^The leftmost column is number 0. 2863** 2864** ^The returned string pointer is valid until either the [prepared statement] 2865** is destroyed by [sqlite3_finalize()] or until the next call to 2866** sqlite3_column_name() or sqlite3_column_name16() on the same column. 2867** 2868** ^If sqlite3_malloc() fails during the processing of either routine 2869** (for example during a conversion from UTF-8 to UTF-16) then a 2870** NULL pointer is returned. 2871** 2872** ^The name of a result column is the value of the "AS" clause for 2873** that column, if there is an AS clause. If there is no AS clause 2874** then the name of the column is unspecified and may change from 2875** one release of SQLite to the next. 2876*/ 2877const char *sqlite3_column_name(sqlite3_stmt*, int N); 2878const void *sqlite3_column_name16(sqlite3_stmt*, int N); 2879 2880/* 2881** CAPI3REF: Source Of Data In A Query Result 2882** 2883** ^These routines provide a means to determine the database, table, and 2884** table column that is the origin of a particular result column in 2885** [SELECT] statement. 2886** ^The name of the database or table or column can be returned as 2887** either a UTF-8 or UTF-16 string. ^The _database_ routines return 2888** the database name, the _table_ routines return the table name, and 2889** the origin_ routines return the column name. 2890** ^The returned string is valid until the [prepared statement] is destroyed 2891** using [sqlite3_finalize()] or until the same information is requested 2892** again in a different encoding. 2893** 2894** ^The names returned are the original un-aliased names of the 2895** database, table, and column. 2896** 2897** ^The first argument to these interfaces is a [prepared statement]. 2898** ^These functions return information about the Nth result column returned by 2899** the statement, where N is the second function argument. 2900** ^The left-most column is column 0 for these routines. 2901** 2902** ^If the Nth column returned by the statement is an expression or 2903** subquery and is not a column value, then all of these functions return 2904** NULL. ^These routine might also return NULL if a memory allocation error 2905** occurs. ^Otherwise, they return the name of the attached database, table, 2906** or column that query result column was extracted from. 2907** 2908** ^As with all other SQLite APIs, those whose names end with "16" return 2909** UTF-16 encoded strings and the other functions return UTF-8. 2910** 2911** ^These APIs are only available if the library was compiled with the 2912** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 2913** 2914** If two or more threads call one or more of these routines against the same 2915** prepared statement and column at the same time then the results are 2916** undefined. 2917** 2918** If two or more threads call one or more 2919** [sqlite3_column_database_name | column metadata interfaces] 2920** for the same [prepared statement] and result column 2921** at the same time then the results are undefined. 2922*/ 2923const char *sqlite3_column_database_name(sqlite3_stmt*,int); 2924const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 2925const char *sqlite3_column_table_name(sqlite3_stmt*,int); 2926const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 2927const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 2928const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 2929 2930/* 2931** CAPI3REF: Declared Datatype Of A Query Result 2932** 2933** ^(The first parameter is a [prepared statement]. 2934** If this statement is a [SELECT] statement and the Nth column of the 2935** returned result set of that [SELECT] is a table column (not an 2936** expression or subquery) then the declared type of the table 2937** column is returned.)^ ^If the Nth column of the result set is an 2938** expression or subquery, then a NULL pointer is returned. 2939** ^The returned string is always UTF-8 encoded. 2940** 2941** ^(For example, given the database schema: 2942** 2943** CREATE TABLE t1(c1 VARIANT); 2944** 2945** and the following statement to be compiled: 2946** 2947** SELECT c1 + 1, c1 FROM t1; 2948** 2949** this routine would return the string "VARIANT" for the second result 2950** column (i==1), and a NULL pointer for the first result column (i==0).)^ 2951** 2952** ^SQLite uses dynamic run-time typing. ^So just because a column 2953** is declared to contain a particular type does not mean that the 2954** data stored in that column is of the declared type. SQLite is 2955** strongly typed, but the typing is dynamic not static. ^Type 2956** is associated with individual values, not with the containers 2957** used to hold those values. 2958*/ 2959const char *sqlite3_column_decltype(sqlite3_stmt*,int); 2960const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 2961 2962/* 2963** CAPI3REF: Evaluate An SQL Statement 2964** 2965** After a [prepared statement] has been prepared using either 2966** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy 2967** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 2968** must be called one or more times to evaluate the statement. 2969** 2970** The details of the behavior of the sqlite3_step() interface depend 2971** on whether the statement was prepared using the newer "v2" interface 2972** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy 2973** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 2974** new "v2" interface is recommended for new applications but the legacy 2975** interface will continue to be supported. 2976** 2977** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 2978** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 2979** ^With the "v2" interface, any of the other [result codes] or 2980** [extended result codes] might be returned as well. 2981** 2982** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 2983** database locks it needs to do its job. ^If the statement is a [COMMIT] 2984** or occurs outside of an explicit transaction, then you can retry the 2985** statement. If the statement is not a [COMMIT] and occurs within a 2986** explicit transaction then you should rollback the transaction before 2987** continuing. 2988** 2989** ^[SQLITE_DONE] means that the statement has finished executing 2990** successfully. sqlite3_step() should not be called again on this virtual 2991** machine without first calling [sqlite3_reset()] to reset the virtual 2992** machine back to its initial state. 2993** 2994** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 2995** is returned each time a new row of data is ready for processing by the 2996** caller. The values may be accessed using the [column access functions]. 2997** sqlite3_step() is called again to retrieve the next row of data. 2998** 2999** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 3000** violation) has occurred. sqlite3_step() should not be called again on 3001** the VM. More information may be found by calling [sqlite3_errmsg()]. 3002** ^With the legacy interface, a more specific error code (for example, 3003** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 3004** can be obtained by calling [sqlite3_reset()] on the 3005** [prepared statement]. ^In the "v2" interface, 3006** the more specific error code is returned directly by sqlite3_step(). 3007** 3008** [SQLITE_MISUSE] means that the this routine was called inappropriately. 3009** Perhaps it was called on a [prepared statement] that has 3010** already been [sqlite3_finalize | finalized] or on one that had 3011** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 3012** be the case that the same database connection is being used by two or 3013** more threads at the same moment in time. 3014** 3015** For all versions of SQLite up to and including 3.6.23.1, it was required 3016** after sqlite3_step() returned anything other than [SQLITE_ROW] that 3017** [sqlite3_reset()] be called before any subsequent invocation of 3018** sqlite3_step(). Failure to invoke [sqlite3_reset()] in this way would 3019** result in an [SQLITE_MISUSE] return from sqlite3_step(). But after 3020** version 3.6.23.1, sqlite3_step() began calling [sqlite3_reset()] 3021** automatically in this circumstance rather than returning [SQLITE_MISUSE]. 3022** 3023** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 3024** API always returns a generic error code, [SQLITE_ERROR], following any 3025** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 3026** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 3027** specific [error codes] that better describes the error. 3028** We admit that this is a goofy design. The problem has been fixed 3029** with the "v2" interface. If you prepare all of your SQL statements 3030** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead 3031** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 3032** then the more specific [error codes] are returned directly 3033** by sqlite3_step(). The use of the "v2" interface is recommended. 3034*/ 3035int sqlite3_step(sqlite3_stmt*); 3036 3037/* 3038** CAPI3REF: Number of columns in a result set 3039** 3040** ^The sqlite3_data_count(P) interface returns the number of columns in the 3041** current row of the result set of [prepared statement] P. 3042** ^If prepared statement P does not have results ready to return 3043** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 3044** interfaces) then sqlite3_data_count(P) returns 0. 3045** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 3046** 3047** See also: [sqlite3_column_count()] 3048*/ 3049int sqlite3_data_count(sqlite3_stmt *pStmt); 3050 3051/* 3052** CAPI3REF: Fundamental Datatypes 3053** KEYWORDS: SQLITE_TEXT 3054** 3055** ^(Every value in SQLite has one of five fundamental datatypes: 3056** 3057** <ul> 3058** <li> 64-bit signed integer 3059** <li> 64-bit IEEE floating point number 3060** <li> string 3061** <li> BLOB 3062** <li> NULL 3063** </ul>)^ 3064** 3065** These constants are codes for each of those types. 3066** 3067** Note that the SQLITE_TEXT constant was also used in SQLite version 2 3068** for a completely different meaning. Software that links against both 3069** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 3070** SQLITE_TEXT. 3071*/ 3072#define SQLITE_INTEGER 1 3073#define SQLITE_FLOAT 2 3074#define SQLITE_BLOB 4 3075#define SQLITE_NULL 5 3076#ifdef SQLITE_TEXT 3077# undef SQLITE_TEXT 3078#else 3079# define SQLITE_TEXT 3 3080#endif 3081#define SQLITE3_TEXT 3 3082 3083/* 3084** CAPI3REF: Result Values From A Query 3085** KEYWORDS: {column access functions} 3086** 3087** These routines form the "result set" interface. 3088** 3089** ^These routines return information about a single column of the current 3090** result row of a query. ^In every case the first argument is a pointer 3091** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 3092** that was returned from [sqlite3_prepare_v2()] or one of its variants) 3093** and the second argument is the index of the column for which information 3094** should be returned. ^The leftmost column of the result set has the index 0. 3095** ^The number of columns in the result can be determined using 3096** [sqlite3_column_count()]. 3097** 3098** If the SQL statement does not currently point to a valid row, or if the 3099** column index is out of range, the result is undefined. 3100** These routines may only be called when the most recent call to 3101** [sqlite3_step()] has returned [SQLITE_ROW] and neither 3102** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 3103** If any of these routines are called after [sqlite3_reset()] or 3104** [sqlite3_finalize()] or after [sqlite3_step()] has returned 3105** something other than [SQLITE_ROW], the results are undefined. 3106** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 3107** are called from a different thread while any of these routines 3108** are pending, then the results are undefined. 3109** 3110** ^The sqlite3_column_type() routine returns the 3111** [SQLITE_INTEGER | datatype code] for the initial data type 3112** of the result column. ^The returned value is one of [SQLITE_INTEGER], 3113** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value 3114** returned by sqlite3_column_type() is only meaningful if no type 3115** conversions have occurred as described below. After a type conversion, 3116** the value returned by sqlite3_column_type() is undefined. Future 3117** versions of SQLite may change the behavior of sqlite3_column_type() 3118** following a type conversion. 3119** 3120** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 3121** routine returns the number of bytes in that BLOB or string. 3122** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 3123** the string to UTF-8 and then returns the number of bytes. 3124** ^If the result is a numeric value then sqlite3_column_bytes() uses 3125** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 3126** the number of bytes in that string. 3127** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 3128** 3129** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 3130** routine returns the number of bytes in that BLOB or string. 3131** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 3132** the string to UTF-16 and then returns the number of bytes. 3133** ^If the result is a numeric value then sqlite3_column_bytes16() uses 3134** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 3135** the number of bytes in that string. 3136** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 3137** 3138** ^The values returned by [sqlite3_column_bytes()] and 3139** [sqlite3_column_bytes16()] do not include the zero terminators at the end 3140** of the string. ^For clarity: the values returned by 3141** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 3142** bytes in the string, not the number of characters. 3143** 3144** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 3145** even empty strings, are always zero terminated. ^The return 3146** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 3147** 3148** ^The object returned by [sqlite3_column_value()] is an 3149** [unprotected sqlite3_value] object. An unprotected sqlite3_value object 3150** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()]. 3151** If the [unprotected sqlite3_value] object returned by 3152** [sqlite3_column_value()] is used in any other way, including calls 3153** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 3154** or [sqlite3_value_bytes()], then the behavior is undefined. 3155** 3156** These routines attempt to convert the value where appropriate. ^For 3157** example, if the internal representation is FLOAT and a text result 3158** is requested, [sqlite3_snprintf()] is used internally to perform the 3159** conversion automatically. ^(The following table details the conversions 3160** that are applied: 3161** 3162** <blockquote> 3163** <table border="1"> 3164** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 3165** 3166** <tr><td> NULL <td> INTEGER <td> Result is 0 3167** <tr><td> NULL <td> FLOAT <td> Result is 0.0 3168** <tr><td> NULL <td> TEXT <td> Result is NULL pointer 3169** <tr><td> NULL <td> BLOB <td> Result is NULL pointer 3170** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 3171** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 3172** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 3173** <tr><td> FLOAT <td> INTEGER <td> Convert from float to integer 3174** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 3175** <tr><td> FLOAT <td> BLOB <td> Same as FLOAT->TEXT 3176** <tr><td> TEXT <td> INTEGER <td> Use atoi() 3177** <tr><td> TEXT <td> FLOAT <td> Use atof() 3178** <tr><td> TEXT <td> BLOB <td> No change 3179** <tr><td> BLOB <td> INTEGER <td> Convert to TEXT then use atoi() 3180** <tr><td> BLOB <td> FLOAT <td> Convert to TEXT then use atof() 3181** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 3182** </table> 3183** </blockquote>)^ 3184** 3185** The table above makes reference to standard C library functions atoi() 3186** and atof(). SQLite does not really use these functions. It has its 3187** own equivalent internal routines. The atoi() and atof() names are 3188** used in the table for brevity and because they are familiar to most 3189** C programmers. 3190** 3191** Note that when type conversions occur, pointers returned by prior 3192** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 3193** sqlite3_column_text16() may be invalidated. 3194** Type conversions and pointer invalidations might occur 3195** in the following cases: 3196** 3197** <ul> 3198** <li> The initial content is a BLOB and sqlite3_column_text() or 3199** sqlite3_column_text16() is called. A zero-terminator might 3200** need to be added to the string.</li> 3201** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 3202** sqlite3_column_text16() is called. The content must be converted 3203** to UTF-16.</li> 3204** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 3205** sqlite3_column_text() is called. The content must be converted 3206** to UTF-8.</li> 3207** </ul> 3208** 3209** ^Conversions between UTF-16be and UTF-16le are always done in place and do 3210** not invalidate a prior pointer, though of course the content of the buffer 3211** that the prior pointer references will have been modified. Other kinds 3212** of conversion are done in place when it is possible, but sometimes they 3213** are not possible and in those cases prior pointers are invalidated. 3214** 3215** The safest and easiest to remember policy is to invoke these routines 3216** in one of the following ways: 3217** 3218** <ul> 3219** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 3220** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 3221** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 3222** </ul> 3223** 3224** In other words, you should call sqlite3_column_text(), 3225** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 3226** into the desired format, then invoke sqlite3_column_bytes() or 3227** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 3228** to sqlite3_column_text() or sqlite3_column_blob() with calls to 3229** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 3230** with calls to sqlite3_column_bytes(). 3231** 3232** ^The pointers returned are valid until a type conversion occurs as 3233** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 3234** [sqlite3_finalize()] is called. ^The memory space used to hold strings 3235** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned 3236** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 3237** [sqlite3_free()]. 3238** 3239** ^(If a memory allocation error occurs during the evaluation of any 3240** of these routines, a default value is returned. The default value 3241** is either the integer 0, the floating point number 0.0, or a NULL 3242** pointer. Subsequent calls to [sqlite3_errcode()] will return 3243** [SQLITE_NOMEM].)^ 3244*/ 3245const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 3246int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 3247int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 3248double sqlite3_column_double(sqlite3_stmt*, int iCol); 3249int sqlite3_column_int(sqlite3_stmt*, int iCol); 3250sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 3251const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 3252const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 3253int sqlite3_column_type(sqlite3_stmt*, int iCol); 3254sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 3255 3256/* 3257** CAPI3REF: Destroy A Prepared Statement Object 3258** 3259** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 3260** ^If the statement was executed successfully or not executed at all, then 3261** SQLITE_OK is returned. ^If execution of the statement failed then an 3262** [error code] or [extended error code] is returned. 3263** 3264** ^This routine can be called at any point during the execution of the 3265** [prepared statement]. ^If the virtual machine has not 3266** completed execution when this routine is called, that is like 3267** encountering an error or an [sqlite3_interrupt | interrupt]. 3268** ^Incomplete updates may be rolled back and transactions canceled, 3269** depending on the circumstances, and the 3270** [error code] returned will be [SQLITE_ABORT]. 3271*/ 3272int sqlite3_finalize(sqlite3_stmt *pStmt); 3273 3274/* 3275** CAPI3REF: Reset A Prepared Statement Object 3276** 3277** The sqlite3_reset() function is called to reset a [prepared statement] 3278** object back to its initial state, ready to be re-executed. 3279** ^Any SQL statement variables that had values bound to them using 3280** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 3281** Use [sqlite3_clear_bindings()] to reset the bindings. 3282** 3283** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 3284** back to the beginning of its program. 3285** 3286** ^If the most recent call to [sqlite3_step(S)] for the 3287** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 3288** or if [sqlite3_step(S)] has never before been called on S, 3289** then [sqlite3_reset(S)] returns [SQLITE_OK]. 3290** 3291** ^If the most recent call to [sqlite3_step(S)] for the 3292** [prepared statement] S indicated an error, then 3293** [sqlite3_reset(S)] returns an appropriate [error code]. 3294** 3295** ^The [sqlite3_reset(S)] interface does not change the values 3296** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 3297*/ 3298int sqlite3_reset(sqlite3_stmt *pStmt); 3299 3300/* 3301** CAPI3REF: Create Or Redefine SQL Functions 3302** KEYWORDS: {function creation routines} 3303** KEYWORDS: {application-defined SQL function} 3304** KEYWORDS: {application-defined SQL functions} 3305** 3306** ^These functions (collectively known as "function creation routines") 3307** are used to add SQL functions or aggregates or to redefine the behavior 3308** of existing SQL functions or aggregates. The only differences between 3309** these routines are the text encoding expected for 3310** the the second parameter (the name of the function being created) 3311** and the presence or absence of a destructor callback for 3312** the application data pointer. 3313** 3314** ^The first parameter is the [database connection] to which the SQL 3315** function is to be added. ^If an application uses more than one database 3316** connection then application-defined SQL functions must be added 3317** to each database connection separately. 3318** 3319** ^The second parameter is the name of the SQL function to be created or 3320** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 3321** representation, exclusive of the zero-terminator. ^Note that the name 3322** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 3323** ^Any attempt to create a function with a longer name 3324** will result in [SQLITE_MISUSE] being returned. 3325** 3326** ^The third parameter (nArg) 3327** is the number of arguments that the SQL function or 3328** aggregate takes. ^If this parameter is -1, then the SQL function or 3329** aggregate may take any number of arguments between 0 and the limit 3330** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 3331** parameter is less than -1 or greater than 127 then the behavior is 3332** undefined. 3333** 3334** ^The fourth parameter, eTextRep, specifies what 3335** [SQLITE_UTF8 | text encoding] this SQL function prefers for 3336** its parameters. Every SQL function implementation must be able to work 3337** with UTF-8, UTF-16le, or UTF-16be. But some implementations may be 3338** more efficient with one encoding than another. ^An application may 3339** invoke sqlite3_create_function() or sqlite3_create_function16() multiple 3340** times with the same function but with different values of eTextRep. 3341** ^When multiple implementations of the same function are available, SQLite 3342** will pick the one that involves the least amount of data conversion. 3343** If there is only a single implementation which does not care what text 3344** encoding is used, then the fourth argument should be [SQLITE_ANY]. 3345** 3346** ^(The fifth parameter is an arbitrary pointer. The implementation of the 3347** function can gain access to this pointer using [sqlite3_user_data()].)^ 3348** 3349** ^The seventh, eighth and ninth parameters, xFunc, xStep and xFinal, are 3350** pointers to C-language functions that implement the SQL function or 3351** aggregate. ^A scalar SQL function requires an implementation of the xFunc 3352** callback only; NULL pointers must be passed as the xStep and xFinal 3353** parameters. ^An aggregate SQL function requires an implementation of xStep 3354** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 3355** SQL function or aggregate, pass NULL poiners for all three function 3356** callbacks. 3357** 3358** ^If the tenth parameter to sqlite3_create_function_v2() is not NULL, 3359** then it is invoked when the function is deleted, either by being 3360** overloaded or when the database connection closes. 3361** ^When the destructure callback of the tenth parameter is invoked, it 3362** is passed a single argument which is a copy of the pointer which was 3363** the fifth parameter to sqlite3_create_function_v2(). 3364** 3365** ^It is permitted to register multiple implementations of the same 3366** functions with the same name but with either differing numbers of 3367** arguments or differing preferred text encodings. ^SQLite will use 3368** the implementation that most closely matches the way in which the 3369** SQL function is used. ^A function implementation with a non-negative 3370** nArg parameter is a better match than a function implementation with 3371** a negative nArg. ^A function where the preferred text encoding 3372** matches the database encoding is a better 3373** match than a function where the encoding is different. 3374** ^A function where the encoding difference is between UTF16le and UTF16be 3375** is a closer match than a function where the encoding difference is 3376** between UTF8 and UTF16. 3377** 3378** ^Built-in functions may be overloaded by new application-defined functions. 3379** 3380** ^An application-defined function is permitted to call other 3381** SQLite interfaces. However, such calls must not 3382** close the database connection nor finalize or reset the prepared 3383** statement in which the function is running. 3384*/ 3385int sqlite3_create_function( 3386 sqlite3 *db, 3387 const char *zFunctionName, 3388 int nArg, 3389 int eTextRep, 3390 void *pApp, 3391 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3392 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3393 void (*xFinal)(sqlite3_context*) 3394); 3395int sqlite3_create_function16( 3396 sqlite3 *db, 3397 const void *zFunctionName, 3398 int nArg, 3399 int eTextRep, 3400 void *pApp, 3401 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3402 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3403 void (*xFinal)(sqlite3_context*) 3404); 3405int sqlite3_create_function_v2( 3406 sqlite3 *db, 3407 const char *zFunctionName, 3408 int nArg, 3409 int eTextRep, 3410 void *pApp, 3411 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3412 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3413 void (*xFinal)(sqlite3_context*), 3414 void(*xDestroy)(void*) 3415); 3416 3417/* 3418** CAPI3REF: Text Encodings 3419** 3420** These constant define integer codes that represent the various 3421** text encodings supported by SQLite. 3422*/ 3423#define SQLITE_UTF8 1 3424#define SQLITE_UTF16LE 2 3425#define SQLITE_UTF16BE 3 3426#define SQLITE_UTF16 4 /* Use native byte order */ 3427#define SQLITE_ANY 5 /* sqlite3_create_function only */ 3428#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 3429 3430/* 3431** CAPI3REF: Deprecated Functions 3432** DEPRECATED 3433** 3434** These functions are [deprecated]. In order to maintain 3435** backwards compatibility with older code, these functions continue 3436** to be supported. However, new applications should avoid 3437** the use of these functions. To help encourage people to avoid 3438** using these functions, we are not going to tell you what they do. 3439*/ 3440#ifndef SQLITE_OMIT_DEPRECATED 3441SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 3442SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 3443SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 3444SQLITE_DEPRECATED int sqlite3_global_recover(void); 3445SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 3446SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64); 3447#endif 3448 3449/* 3450** CAPI3REF: Obtaining SQL Function Parameter Values 3451** 3452** The C-language implementation of SQL functions and aggregates uses 3453** this set of interface routines to access the parameter values on 3454** the function or aggregate. 3455** 3456** The xFunc (for scalar functions) or xStep (for aggregates) parameters 3457** to [sqlite3_create_function()] and [sqlite3_create_function16()] 3458** define callbacks that implement the SQL functions and aggregates. 3459** The 4th parameter to these callbacks is an array of pointers to 3460** [protected sqlite3_value] objects. There is one [sqlite3_value] object for 3461** each parameter to the SQL function. These routines are used to 3462** extract values from the [sqlite3_value] objects. 3463** 3464** These routines work only with [protected sqlite3_value] objects. 3465** Any attempt to use these routines on an [unprotected sqlite3_value] 3466** object results in undefined behavior. 3467** 3468** ^These routines work just like the corresponding [column access functions] 3469** except that these routines take a single [protected sqlite3_value] object 3470** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 3471** 3472** ^The sqlite3_value_text16() interface extracts a UTF-16 string 3473** in the native byte-order of the host machine. ^The 3474** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 3475** extract UTF-16 strings as big-endian and little-endian respectively. 3476** 3477** ^(The sqlite3_value_numeric_type() interface attempts to apply 3478** numeric affinity to the value. This means that an attempt is 3479** made to convert the value to an integer or floating point. If 3480** such a conversion is possible without loss of information (in other 3481** words, if the value is a string that looks like a number) 3482** then the conversion is performed. Otherwise no conversion occurs. 3483** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 3484** 3485** Please pay particular attention to the fact that the pointer returned 3486** from [sqlite3_value_blob()], [sqlite3_value_text()], or 3487** [sqlite3_value_text16()] can be invalidated by a subsequent call to 3488** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 3489** or [sqlite3_value_text16()]. 3490** 3491** These routines must be called from the same thread as 3492** the SQL function that supplied the [sqlite3_value*] parameters. 3493*/ 3494const void *sqlite3_value_blob(sqlite3_value*); 3495int sqlite3_value_bytes(sqlite3_value*); 3496int sqlite3_value_bytes16(sqlite3_value*); 3497double sqlite3_value_double(sqlite3_value*); 3498int sqlite3_value_int(sqlite3_value*); 3499sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 3500const unsigned char *sqlite3_value_text(sqlite3_value*); 3501const void *sqlite3_value_text16(sqlite3_value*); 3502const void *sqlite3_value_text16le(sqlite3_value*); 3503const void *sqlite3_value_text16be(sqlite3_value*); 3504int sqlite3_value_type(sqlite3_value*); 3505int sqlite3_value_numeric_type(sqlite3_value*); 3506 3507/* 3508** CAPI3REF: Obtain Aggregate Function Context 3509** 3510** Implementations of aggregate SQL functions use this 3511** routine to allocate memory for storing their state. 3512** 3513** ^The first time the sqlite3_aggregate_context(C,N) routine is called 3514** for a particular aggregate function, SQLite 3515** allocates N of memory, zeroes out that memory, and returns a pointer 3516** to the new memory. ^On second and subsequent calls to 3517** sqlite3_aggregate_context() for the same aggregate function instance, 3518** the same buffer is returned. Sqlite3_aggregate_context() is normally 3519** called once for each invocation of the xStep callback and then one 3520** last time when the xFinal callback is invoked. ^(When no rows match 3521** an aggregate query, the xStep() callback of the aggregate function 3522** implementation is never called and xFinal() is called exactly once. 3523** In those cases, sqlite3_aggregate_context() might be called for the 3524** first time from within xFinal().)^ 3525** 3526** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer if N is 3527** less than or equal to zero or if a memory allocate error occurs. 3528** 3529** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 3530** determined by the N parameter on first successful call. Changing the 3531** value of N in subsequent call to sqlite3_aggregate_context() within 3532** the same aggregate function instance will not resize the memory 3533** allocation.)^ 3534** 3535** ^SQLite automatically frees the memory allocated by 3536** sqlite3_aggregate_context() when the aggregate query concludes. 3537** 3538** The first parameter must be a copy of the 3539** [sqlite3_context | SQL function context] that is the first parameter 3540** to the xStep or xFinal callback routine that implements the aggregate 3541** function. 3542** 3543** This routine must be called from the same thread in which 3544** the aggregate SQL function is running. 3545*/ 3546void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 3547 3548/* 3549** CAPI3REF: User Data For Functions 3550** 3551** ^The sqlite3_user_data() interface returns a copy of 3552** the pointer that was the pUserData parameter (the 5th parameter) 3553** of the [sqlite3_create_function()] 3554** and [sqlite3_create_function16()] routines that originally 3555** registered the application defined function. 3556** 3557** This routine must be called from the same thread in which 3558** the application-defined function is running. 3559*/ 3560void *sqlite3_user_data(sqlite3_context*); 3561 3562/* 3563** CAPI3REF: Database Connection For Functions 3564** 3565** ^The sqlite3_context_db_handle() interface returns a copy of 3566** the pointer to the [database connection] (the 1st parameter) 3567** of the [sqlite3_create_function()] 3568** and [sqlite3_create_function16()] routines that originally 3569** registered the application defined function. 3570*/ 3571sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 3572 3573/* 3574** CAPI3REF: Function Auxiliary Data 3575** 3576** The following two functions may be used by scalar SQL functions to 3577** associate metadata with argument values. If the same value is passed to 3578** multiple invocations of the same SQL function during query execution, under 3579** some circumstances the associated metadata may be preserved. This may 3580** be used, for example, to add a regular-expression matching scalar 3581** function. The compiled version of the regular expression is stored as 3582** metadata associated with the SQL value passed as the regular expression 3583** pattern. The compiled regular expression can be reused on multiple 3584** invocations of the same function so that the original pattern string 3585** does not need to be recompiled on each invocation. 3586** 3587** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata 3588** associated by the sqlite3_set_auxdata() function with the Nth argument 3589** value to the application-defined function. ^If no metadata has been ever 3590** been set for the Nth argument of the function, or if the corresponding 3591** function parameter has changed since the meta-data was set, 3592** then sqlite3_get_auxdata() returns a NULL pointer. 3593** 3594** ^The sqlite3_set_auxdata() interface saves the metadata 3595** pointed to by its 3rd parameter as the metadata for the N-th 3596** argument of the application-defined function. Subsequent 3597** calls to sqlite3_get_auxdata() might return this data, if it has 3598** not been destroyed. 3599** ^If it is not NULL, SQLite will invoke the destructor 3600** function given by the 4th parameter to sqlite3_set_auxdata() on 3601** the metadata when the corresponding function parameter changes 3602** or when the SQL statement completes, whichever comes first. 3603** 3604** SQLite is free to call the destructor and drop metadata on any 3605** parameter of any function at any time. ^The only guarantee is that 3606** the destructor will be called before the metadata is dropped. 3607** 3608** ^(In practice, metadata is preserved between function calls for 3609** expressions that are constant at compile time. This includes literal 3610** values and [parameters].)^ 3611** 3612** These routines must be called from the same thread in which 3613** the SQL function is running. 3614*/ 3615void *sqlite3_get_auxdata(sqlite3_context*, int N); 3616void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 3617 3618 3619/* 3620** CAPI3REF: Constants Defining Special Destructor Behavior 3621** 3622** These are special values for the destructor that is passed in as the 3623** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 3624** argument is SQLITE_STATIC, it means that the content pointer is constant 3625** and will never change. It does not need to be destroyed. ^The 3626** SQLITE_TRANSIENT value means that the content will likely change in 3627** the near future and that SQLite should make its own private copy of 3628** the content before returning. 3629** 3630** The typedef is necessary to work around problems in certain 3631** C++ compilers. See ticket #2191. 3632*/ 3633typedef void (*sqlite3_destructor_type)(void*); 3634#define SQLITE_STATIC ((sqlite3_destructor_type)0) 3635#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 3636 3637/* 3638** CAPI3REF: Setting The Result Of An SQL Function 3639** 3640** These routines are used by the xFunc or xFinal callbacks that 3641** implement SQL functions and aggregates. See 3642** [sqlite3_create_function()] and [sqlite3_create_function16()] 3643** for additional information. 3644** 3645** These functions work very much like the [parameter binding] family of 3646** functions used to bind values to host parameters in prepared statements. 3647** Refer to the [SQL parameter] documentation for additional information. 3648** 3649** ^The sqlite3_result_blob() interface sets the result from 3650** an application-defined function to be the BLOB whose content is pointed 3651** to by the second parameter and which is N bytes long where N is the 3652** third parameter. 3653** 3654** ^The sqlite3_result_zeroblob() interfaces set the result of 3655** the application-defined function to be a BLOB containing all zero 3656** bytes and N bytes in size, where N is the value of the 2nd parameter. 3657** 3658** ^The sqlite3_result_double() interface sets the result from 3659** an application-defined function to be a floating point value specified 3660** by its 2nd argument. 3661** 3662** ^The sqlite3_result_error() and sqlite3_result_error16() functions 3663** cause the implemented SQL function to throw an exception. 3664** ^SQLite uses the string pointed to by the 3665** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 3666** as the text of an error message. ^SQLite interprets the error 3667** message string from sqlite3_result_error() as UTF-8. ^SQLite 3668** interprets the string from sqlite3_result_error16() as UTF-16 in native 3669** byte order. ^If the third parameter to sqlite3_result_error() 3670** or sqlite3_result_error16() is negative then SQLite takes as the error 3671** message all text up through the first zero character. 3672** ^If the third parameter to sqlite3_result_error() or 3673** sqlite3_result_error16() is non-negative then SQLite takes that many 3674** bytes (not characters) from the 2nd parameter as the error message. 3675** ^The sqlite3_result_error() and sqlite3_result_error16() 3676** routines make a private copy of the error message text before 3677** they return. Hence, the calling function can deallocate or 3678** modify the text after they return without harm. 3679** ^The sqlite3_result_error_code() function changes the error code 3680** returned by SQLite as a result of an error in a function. ^By default, 3681** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 3682** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 3683** 3684** ^The sqlite3_result_toobig() interface causes SQLite to throw an error 3685** indicating that a string or BLOB is too long to represent. 3686** 3687** ^The sqlite3_result_nomem() interface causes SQLite to throw an error 3688** indicating that a memory allocation failed. 3689** 3690** ^The sqlite3_result_int() interface sets the return value 3691** of the application-defined function to be the 32-bit signed integer 3692** value given in the 2nd argument. 3693** ^The sqlite3_result_int64() interface sets the return value 3694** of the application-defined function to be the 64-bit signed integer 3695** value given in the 2nd argument. 3696** 3697** ^The sqlite3_result_null() interface sets the return value 3698** of the application-defined function to be NULL. 3699** 3700** ^The sqlite3_result_text(), sqlite3_result_text16(), 3701** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 3702** set the return value of the application-defined function to be 3703** a text string which is represented as UTF-8, UTF-16 native byte order, 3704** UTF-16 little endian, or UTF-16 big endian, respectively. 3705** ^SQLite takes the text result from the application from 3706** the 2nd parameter of the sqlite3_result_text* interfaces. 3707** ^If the 3rd parameter to the sqlite3_result_text* interfaces 3708** is negative, then SQLite takes result text from the 2nd parameter 3709** through the first zero character. 3710** ^If the 3rd parameter to the sqlite3_result_text* interfaces 3711** is non-negative, then as many bytes (not characters) of the text 3712** pointed to by the 2nd parameter are taken as the application-defined 3713** function result. 3714** ^If the 4th parameter to the sqlite3_result_text* interfaces 3715** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 3716** function as the destructor on the text or BLOB result when it has 3717** finished using that result. 3718** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 3719** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 3720** assumes that the text or BLOB result is in constant space and does not 3721** copy the content of the parameter nor call a destructor on the content 3722** when it has finished using that result. 3723** ^If the 4th parameter to the sqlite3_result_text* interfaces 3724** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 3725** then SQLite makes a copy of the result into space obtained from 3726** from [sqlite3_malloc()] before it returns. 3727** 3728** ^The sqlite3_result_value() interface sets the result of 3729** the application-defined function to be a copy the 3730** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 3731** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 3732** so that the [sqlite3_value] specified in the parameter may change or 3733** be deallocated after sqlite3_result_value() returns without harm. 3734** ^A [protected sqlite3_value] object may always be used where an 3735** [unprotected sqlite3_value] object is required, so either 3736** kind of [sqlite3_value] object can be used with this interface. 3737** 3738** If these routines are called from within the different thread 3739** than the one containing the application-defined function that received 3740** the [sqlite3_context] pointer, the results are undefined. 3741*/ 3742void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 3743void sqlite3_result_double(sqlite3_context*, double); 3744void sqlite3_result_error(sqlite3_context*, const char*, int); 3745void sqlite3_result_error16(sqlite3_context*, const void*, int); 3746void sqlite3_result_error_toobig(sqlite3_context*); 3747void sqlite3_result_error_nomem(sqlite3_context*); 3748void sqlite3_result_error_code(sqlite3_context*, int); 3749void sqlite3_result_int(sqlite3_context*, int); 3750void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 3751void sqlite3_result_null(sqlite3_context*); 3752void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 3753void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 3754void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 3755void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 3756void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 3757void sqlite3_result_zeroblob(sqlite3_context*, int n); 3758 3759/* 3760** CAPI3REF: Define New Collating Sequences 3761** 3762** These functions are used to add new collation sequences to the 3763** [database connection] specified as the first argument. 3764** 3765** ^The name of the new collation sequence is specified as a UTF-8 string 3766** for sqlite3_create_collation() and sqlite3_create_collation_v2() 3767** and a UTF-16 string for sqlite3_create_collation16(). ^In all cases 3768** the name is passed as the second function argument. 3769** 3770** ^The third argument may be one of the constants [SQLITE_UTF8], 3771** [SQLITE_UTF16LE], or [SQLITE_UTF16BE], indicating that the user-supplied 3772** routine expects to be passed pointers to strings encoded using UTF-8, 3773** UTF-16 little-endian, or UTF-16 big-endian, respectively. ^The 3774** third argument might also be [SQLITE_UTF16] to indicate that the routine 3775** expects pointers to be UTF-16 strings in the native byte order, or the 3776** argument can be [SQLITE_UTF16_ALIGNED] if the 3777** the routine expects pointers to 16-bit word aligned strings 3778** of UTF-16 in the native byte order. 3779** 3780** A pointer to the user supplied routine must be passed as the fifth 3781** argument. ^If it is NULL, this is the same as deleting the collation 3782** sequence (so that SQLite cannot call it any more). 3783** ^Each time the application supplied function is invoked, it is passed 3784** as its first parameter a copy of the void* passed as the fourth argument 3785** to sqlite3_create_collation() or sqlite3_create_collation16(). 3786** 3787** ^The remaining arguments to the application-supplied routine are two strings, 3788** each represented by a (length, data) pair and encoded in the encoding 3789** that was passed as the third argument when the collation sequence was 3790** registered. The application defined collation routine should 3791** return negative, zero or positive if the first string is less than, 3792** equal to, or greater than the second string. i.e. (STRING1 - STRING2). 3793** 3794** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 3795** except that it takes an extra argument which is a destructor for 3796** the collation. ^The destructor is called when the collation is 3797** destroyed and is passed a copy of the fourth parameter void* pointer 3798** of the sqlite3_create_collation_v2(). 3799** ^Collations are destroyed when they are overridden by later calls to the 3800** collation creation functions or when the [database connection] is closed 3801** using [sqlite3_close()]. 3802** 3803** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 3804*/ 3805int sqlite3_create_collation( 3806 sqlite3*, 3807 const char *zName, 3808 int eTextRep, 3809 void*, 3810 int(*xCompare)(void*,int,const void*,int,const void*) 3811); 3812int sqlite3_create_collation_v2( 3813 sqlite3*, 3814 const char *zName, 3815 int eTextRep, 3816 void*, 3817 int(*xCompare)(void*,int,const void*,int,const void*), 3818 void(*xDestroy)(void*) 3819); 3820int sqlite3_create_collation16( 3821 sqlite3*, 3822 const void *zName, 3823 int eTextRep, 3824 void*, 3825 int(*xCompare)(void*,int,const void*,int,const void*) 3826); 3827 3828/* 3829** CAPI3REF: Collation Needed Callbacks 3830** 3831** ^To avoid having to register all collation sequences before a database 3832** can be used, a single callback function may be registered with the 3833** [database connection] to be invoked whenever an undefined collation 3834** sequence is required. 3835** 3836** ^If the function is registered using the sqlite3_collation_needed() API, 3837** then it is passed the names of undefined collation sequences as strings 3838** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 3839** the names are passed as UTF-16 in machine native byte order. 3840** ^A call to either function replaces the existing collation-needed callback. 3841** 3842** ^(When the callback is invoked, the first argument passed is a copy 3843** of the second argument to sqlite3_collation_needed() or 3844** sqlite3_collation_needed16(). The second argument is the database 3845** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 3846** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 3847** sequence function required. The fourth parameter is the name of the 3848** required collation sequence.)^ 3849** 3850** The callback function should register the desired collation using 3851** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 3852** [sqlite3_create_collation_v2()]. 3853*/ 3854int sqlite3_collation_needed( 3855 sqlite3*, 3856 void*, 3857 void(*)(void*,sqlite3*,int eTextRep,const char*) 3858); 3859int sqlite3_collation_needed16( 3860 sqlite3*, 3861 void*, 3862 void(*)(void*,sqlite3*,int eTextRep,const void*) 3863); 3864 3865#ifdef SQLITE_HAS_CODEC 3866/* 3867** Specify the key for an encrypted database. This routine should be 3868** called right after sqlite3_open(). 3869** 3870** The code to implement this API is not available in the public release 3871** of SQLite. 3872*/ 3873int sqlite3_key( 3874 sqlite3 *db, /* Database to be rekeyed */ 3875 const void *pKey, int nKey /* The key */ 3876); 3877 3878/* 3879** Change the key on an open database. If the current database is not 3880** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 3881** database is decrypted. 3882** 3883** The code to implement this API is not available in the public release 3884** of SQLite. 3885*/ 3886int sqlite3_rekey( 3887 sqlite3 *db, /* Database to be rekeyed */ 3888 const void *pKey, int nKey /* The new key */ 3889); 3890 3891/* 3892** Specify the activation key for a SEE database. Unless 3893** activated, none of the SEE routines will work. 3894*/ 3895void sqlite3_activate_see( 3896 const char *zPassPhrase /* Activation phrase */ 3897); 3898#endif 3899 3900#ifdef SQLITE_ENABLE_CEROD 3901/* 3902** Specify the activation key for a CEROD database. Unless 3903** activated, none of the CEROD routines will work. 3904*/ 3905void sqlite3_activate_cerod( 3906 const char *zPassPhrase /* Activation phrase */ 3907); 3908#endif 3909 3910/* 3911** CAPI3REF: Suspend Execution For A Short Time 3912** 3913** The sqlite3_sleep() function causes the current thread to suspend execution 3914** for at least a number of milliseconds specified in its parameter. 3915** 3916** If the operating system does not support sleep requests with 3917** millisecond time resolution, then the time will be rounded up to 3918** the nearest second. The number of milliseconds of sleep actually 3919** requested from the operating system is returned. 3920** 3921** ^SQLite implements this interface by calling the xSleep() 3922** method of the default [sqlite3_vfs] object. If the xSleep() method 3923** of the default VFS is not implemented correctly, or not implemented at 3924** all, then the behavior of sqlite3_sleep() may deviate from the description 3925** in the previous paragraphs. 3926*/ 3927int sqlite3_sleep(int); 3928 3929/* 3930** CAPI3REF: Name Of The Folder Holding Temporary Files 3931** 3932** ^(If this global variable is made to point to a string which is 3933** the name of a folder (a.k.a. directory), then all temporary files 3934** created by SQLite when using a built-in [sqlite3_vfs | VFS] 3935** will be placed in that directory.)^ ^If this variable 3936** is a NULL pointer, then SQLite performs a search for an appropriate 3937** temporary file directory. 3938** 3939** It is not safe to read or modify this variable in more than one 3940** thread at a time. It is not safe to read or modify this variable 3941** if a [database connection] is being used at the same time in a separate 3942** thread. 3943** It is intended that this variable be set once 3944** as part of process initialization and before any SQLite interface 3945** routines have been called and that this variable remain unchanged 3946** thereafter. 3947** 3948** ^The [temp_store_directory pragma] may modify this variable and cause 3949** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 3950** the [temp_store_directory pragma] always assumes that any string 3951** that this variable points to is held in memory obtained from 3952** [sqlite3_malloc] and the pragma may attempt to free that memory 3953** using [sqlite3_free]. 3954** Hence, if this variable is modified directly, either it should be 3955** made NULL or made to point to memory obtained from [sqlite3_malloc] 3956** or else the use of the [temp_store_directory pragma] should be avoided. 3957*/ 3958SQLITE_EXTERN char *sqlite3_temp_directory; 3959 3960/* 3961** CAPI3REF: Test For Auto-Commit Mode 3962** KEYWORDS: {autocommit mode} 3963** 3964** ^The sqlite3_get_autocommit() interface returns non-zero or 3965** zero if the given database connection is or is not in autocommit mode, 3966** respectively. ^Autocommit mode is on by default. 3967** ^Autocommit mode is disabled by a [BEGIN] statement. 3968** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 3969** 3970** If certain kinds of errors occur on a statement within a multi-statement 3971** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 3972** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 3973** transaction might be rolled back automatically. The only way to 3974** find out whether SQLite automatically rolled back the transaction after 3975** an error is to use this function. 3976** 3977** If another thread changes the autocommit status of the database 3978** connection while this routine is running, then the return value 3979** is undefined. 3980*/ 3981int sqlite3_get_autocommit(sqlite3*); 3982 3983/* 3984** CAPI3REF: Find The Database Handle Of A Prepared Statement 3985** 3986** ^The sqlite3_db_handle interface returns the [database connection] handle 3987** to which a [prepared statement] belongs. ^The [database connection] 3988** returned by sqlite3_db_handle is the same [database connection] 3989** that was the first argument 3990** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 3991** create the statement in the first place. 3992*/ 3993sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 3994 3995/* 3996** CAPI3REF: Find the next prepared statement 3997** 3998** ^This interface returns a pointer to the next [prepared statement] after 3999** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 4000** then this interface returns a pointer to the first prepared statement 4001** associated with the database connection pDb. ^If no prepared statement 4002** satisfies the conditions of this routine, it returns NULL. 4003** 4004** The [database connection] pointer D in a call to 4005** [sqlite3_next_stmt(D,S)] must refer to an open database 4006** connection and in particular must not be a NULL pointer. 4007*/ 4008sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 4009 4010/* 4011** CAPI3REF: Commit And Rollback Notification Callbacks 4012** 4013** ^The sqlite3_commit_hook() interface registers a callback 4014** function to be invoked whenever a transaction is [COMMIT | committed]. 4015** ^Any callback set by a previous call to sqlite3_commit_hook() 4016** for the same database connection is overridden. 4017** ^The sqlite3_rollback_hook() interface registers a callback 4018** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 4019** ^Any callback set by a previous call to sqlite3_rollback_hook() 4020** for the same database connection is overridden. 4021** ^The pArg argument is passed through to the callback. 4022** ^If the callback on a commit hook function returns non-zero, 4023** then the commit is converted into a rollback. 4024** 4025** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 4026** return the P argument from the previous call of the same function 4027** on the same [database connection] D, or NULL for 4028** the first call for each function on D. 4029** 4030** The callback implementation must not do anything that will modify 4031** the database connection that invoked the callback. Any actions 4032** to modify the database connection must be deferred until after the 4033** completion of the [sqlite3_step()] call that triggered the commit 4034** or rollback hook in the first place. 4035** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 4036** database connections for the meaning of "modify" in this paragraph. 4037** 4038** ^Registering a NULL function disables the callback. 4039** 4040** ^When the commit hook callback routine returns zero, the [COMMIT] 4041** operation is allowed to continue normally. ^If the commit hook 4042** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 4043** ^The rollback hook is invoked on a rollback that results from a commit 4044** hook returning non-zero, just as it would be with any other rollback. 4045** 4046** ^For the purposes of this API, a transaction is said to have been 4047** rolled back if an explicit "ROLLBACK" statement is executed, or 4048** an error or constraint causes an implicit rollback to occur. 4049** ^The rollback callback is not invoked if a transaction is 4050** automatically rolled back because the database connection is closed. 4051** 4052** See also the [sqlite3_update_hook()] interface. 4053*/ 4054void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 4055void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 4056 4057/* 4058** CAPI3REF: Data Change Notification Callbacks 4059** 4060** ^The sqlite3_update_hook() interface registers a callback function 4061** with the [database connection] identified by the first argument 4062** to be invoked whenever a row is updated, inserted or deleted. 4063** ^Any callback set by a previous call to this function 4064** for the same database connection is overridden. 4065** 4066** ^The second argument is a pointer to the function to invoke when a 4067** row is updated, inserted or deleted. 4068** ^The first argument to the callback is a copy of the third argument 4069** to sqlite3_update_hook(). 4070** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 4071** or [SQLITE_UPDATE], depending on the operation that caused the callback 4072** to be invoked. 4073** ^The third and fourth arguments to the callback contain pointers to the 4074** database and table name containing the affected row. 4075** ^The final callback parameter is the [rowid] of the row. 4076** ^In the case of an update, this is the [rowid] after the update takes place. 4077** 4078** ^(The update hook is not invoked when internal system tables are 4079** modified (i.e. sqlite_master and sqlite_sequence).)^ 4080** 4081** ^In the current implementation, the update hook 4082** is not invoked when duplication rows are deleted because of an 4083** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 4084** invoked when rows are deleted using the [truncate optimization]. 4085** The exceptions defined in this paragraph might change in a future 4086** release of SQLite. 4087** 4088** The update hook implementation must not do anything that will modify 4089** the database connection that invoked the update hook. Any actions 4090** to modify the database connection must be deferred until after the 4091** completion of the [sqlite3_step()] call that triggered the update hook. 4092** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 4093** database connections for the meaning of "modify" in this paragraph. 4094** 4095** ^The sqlite3_update_hook(D,C,P) function 4096** returns the P argument from the previous call 4097** on the same [database connection] D, or NULL for 4098** the first call on D. 4099** 4100** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()] 4101** interfaces. 4102*/ 4103void *sqlite3_update_hook( 4104 sqlite3*, 4105 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 4106 void* 4107); 4108 4109/* 4110** CAPI3REF: Enable Or Disable Shared Pager Cache 4111** KEYWORDS: {shared cache} 4112** 4113** ^(This routine enables or disables the sharing of the database cache 4114** and schema data structures between [database connection | connections] 4115** to the same database. Sharing is enabled if the argument is true 4116** and disabled if the argument is false.)^ 4117** 4118** ^Cache sharing is enabled and disabled for an entire process. 4119** This is a change as of SQLite version 3.5.0. In prior versions of SQLite, 4120** sharing was enabled or disabled for each thread separately. 4121** 4122** ^(The cache sharing mode set by this interface effects all subsequent 4123** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 4124** Existing database connections continue use the sharing mode 4125** that was in effect at the time they were opened.)^ 4126** 4127** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 4128** successfully. An [error code] is returned otherwise.)^ 4129** 4130** ^Shared cache is disabled by default. But this might change in 4131** future releases of SQLite. Applications that care about shared 4132** cache setting should set it explicitly. 4133** 4134** See Also: [SQLite Shared-Cache Mode] 4135*/ 4136int sqlite3_enable_shared_cache(int); 4137 4138/* 4139** CAPI3REF: Attempt To Free Heap Memory 4140** 4141** ^The sqlite3_release_memory() interface attempts to free N bytes 4142** of heap memory by deallocating non-essential memory allocations 4143** held by the database library. Memory used to cache database 4144** pages to improve performance is an example of non-essential memory. 4145** ^sqlite3_release_memory() returns the number of bytes actually freed, 4146** which might be more or less than the amount requested. 4147** ^The sqlite3_release_memory() routine is a no-op returning zero 4148** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 4149*/ 4150int sqlite3_release_memory(int); 4151 4152/* 4153** CAPI3REF: Impose A Limit On Heap Size 4154** 4155** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 4156** soft limit on the amount of heap memory that may be allocated by SQLite. 4157** ^SQLite strives to keep heap memory utilization below the soft heap 4158** limit by reducing the number of pages held in the page cache 4159** as heap memory usages approaches the limit. 4160** ^The soft heap limit is "soft" because even though SQLite strives to stay 4161** below the limit, it will exceed the limit rather than generate 4162** an [SQLITE_NOMEM] error. In other words, the soft heap limit 4163** is advisory only. 4164** 4165** ^The return value from sqlite3_soft_heap_limit64() is the size of 4166** the soft heap limit prior to the call. ^If the argument N is negative 4167** then no change is made to the soft heap limit. Hence, the current 4168** size of the soft heap limit can be determined by invoking 4169** sqlite3_soft_heap_limit64() with a negative argument. 4170** 4171** ^If the argument N is zero then the soft heap limit is disabled. 4172** 4173** ^(The soft heap limit is not enforced in the current implementation 4174** if one or more of following conditions are true: 4175** 4176** <ul> 4177** <li> The soft heap limit is set to zero. 4178** <li> Memory accounting is disabled using a combination of the 4179** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 4180** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 4181** <li> An alternative page cache implementation is specifed using 4182** [sqlite3_config]([SQLITE_CONFIG_PCACHE],...). 4183** <li> The page cache allocates from its own memory pool supplied 4184** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 4185** from the heap. 4186** </ul>)^ 4187** 4188** Beginning with SQLite version 3.7.3, the soft heap limit is enforced 4189** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 4190** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 4191** the soft heap limit is enforced on every memory allocation. Without 4192** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 4193** when memory is allocated by the page cache. Testing suggests that because 4194** the page cache is the predominate memory user in SQLite, most 4195** applications will achieve adequate soft heap limit enforcement without 4196** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 4197** 4198** The circumstances under which SQLite will enforce the soft heap limit may 4199** changes in future releases of SQLite. 4200*/ 4201sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 4202 4203/* 4204** CAPI3REF: Deprecated Soft Heap Limit Interface 4205** DEPRECATED 4206** 4207** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 4208** interface. This routine is provided for historical compatibility 4209** only. All new applications should use the 4210** [sqlite3_soft_heap_limit64()] interface rather than this one. 4211*/ 4212SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 4213 4214 4215/* 4216** CAPI3REF: Extract Metadata About A Column Of A Table 4217** 4218** ^This routine returns metadata about a specific column of a specific 4219** database table accessible using the [database connection] handle 4220** passed as the first function argument. 4221** 4222** ^The column is identified by the second, third and fourth parameters to 4223** this function. ^The second parameter is either the name of the database 4224** (i.e. "main", "temp", or an attached database) containing the specified 4225** table or NULL. ^If it is NULL, then all attached databases are searched 4226** for the table using the same algorithm used by the database engine to 4227** resolve unqualified table references. 4228** 4229** ^The third and fourth parameters to this function are the table and column 4230** name of the desired column, respectively. Neither of these parameters 4231** may be NULL. 4232** 4233** ^Metadata is returned by writing to the memory locations passed as the 5th 4234** and subsequent parameters to this function. ^Any of these arguments may be 4235** NULL, in which case the corresponding element of metadata is omitted. 4236** 4237** ^(<blockquote> 4238** <table border="1"> 4239** <tr><th> Parameter <th> Output<br>Type <th> Description 4240** 4241** <tr><td> 5th <td> const char* <td> Data type 4242** <tr><td> 6th <td> const char* <td> Name of default collation sequence 4243** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 4244** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 4245** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 4246** </table> 4247** </blockquote>)^ 4248** 4249** ^The memory pointed to by the character pointers returned for the 4250** declaration type and collation sequence is valid only until the next 4251** call to any SQLite API function. 4252** 4253** ^If the specified table is actually a view, an [error code] is returned. 4254** 4255** ^If the specified column is "rowid", "oid" or "_rowid_" and an 4256** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 4257** parameters are set for the explicitly declared column. ^(If there is no 4258** explicitly declared [INTEGER PRIMARY KEY] column, then the output 4259** parameters are set as follows: 4260** 4261** <pre> 4262** data type: "INTEGER" 4263** collation sequence: "BINARY" 4264** not null: 0 4265** primary key: 1 4266** auto increment: 0 4267** </pre>)^ 4268** 4269** ^(This function may load one or more schemas from database files. If an 4270** error occurs during this process, or if the requested table or column 4271** cannot be found, an [error code] is returned and an error message left 4272** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^ 4273** 4274** ^This API is only available if the library was compiled with the 4275** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined. 4276*/ 4277int sqlite3_table_column_metadata( 4278 sqlite3 *db, /* Connection handle */ 4279 const char *zDbName, /* Database name or NULL */ 4280 const char *zTableName, /* Table name */ 4281 const char *zColumnName, /* Column name */ 4282 char const **pzDataType, /* OUTPUT: Declared data type */ 4283 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 4284 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 4285 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 4286 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 4287); 4288 4289/* 4290** CAPI3REF: Load An Extension 4291** 4292** ^This interface loads an SQLite extension library from the named file. 4293** 4294** ^The sqlite3_load_extension() interface attempts to load an 4295** SQLite extension library contained in the file zFile. 4296** 4297** ^The entry point is zProc. 4298** ^zProc may be 0, in which case the name of the entry point 4299** defaults to "sqlite3_extension_init". 4300** ^The sqlite3_load_extension() interface returns 4301** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 4302** ^If an error occurs and pzErrMsg is not 0, then the 4303** [sqlite3_load_extension()] interface shall attempt to 4304** fill *pzErrMsg with error message text stored in memory 4305** obtained from [sqlite3_malloc()]. The calling function 4306** should free this memory by calling [sqlite3_free()]. 4307** 4308** ^Extension loading must be enabled using 4309** [sqlite3_enable_load_extension()] prior to calling this API, 4310** otherwise an error will be returned. 4311** 4312** See also the [load_extension() SQL function]. 4313*/ 4314int sqlite3_load_extension( 4315 sqlite3 *db, /* Load the extension into this database connection */ 4316 const char *zFile, /* Name of the shared library containing extension */ 4317 const char *zProc, /* Entry point. Derived from zFile if 0 */ 4318 char **pzErrMsg /* Put error message here if not 0 */ 4319); 4320 4321/* 4322** CAPI3REF: Enable Or Disable Extension Loading 4323** 4324** ^So as not to open security holes in older applications that are 4325** unprepared to deal with extension loading, and as a means of disabling 4326** extension loading while evaluating user-entered SQL, the following API 4327** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 4328** 4329** ^Extension loading is off by default. See ticket #1863. 4330** ^Call the sqlite3_enable_load_extension() routine with onoff==1 4331** to turn extension loading on and call it with onoff==0 to turn 4332** it back off again. 4333*/ 4334int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 4335 4336/* 4337** CAPI3REF: Automatically Load An Extensions 4338** 4339** ^This API can be invoked at program startup in order to register 4340** one or more statically linked extensions that will be available 4341** to all new [database connections]. 4342** 4343** ^(This routine stores a pointer to the extension entry point 4344** in an array that is obtained from [sqlite3_malloc()]. That memory 4345** is deallocated by [sqlite3_reset_auto_extension()].)^ 4346** 4347** ^This function registers an extension entry point that is 4348** automatically invoked whenever a new [database connection] 4349** is opened using [sqlite3_open()], [sqlite3_open16()], 4350** or [sqlite3_open_v2()]. 4351** ^Duplicate extensions are detected so calling this routine 4352** multiple times with the same extension is harmless. 4353** ^Automatic extensions apply across all threads. 4354*/ 4355int sqlite3_auto_extension(void (*xEntryPoint)(void)); 4356 4357/* 4358** CAPI3REF: Reset Automatic Extension Loading 4359** 4360** ^(This function disables all previously registered automatic 4361** extensions. It undoes the effect of all prior 4362** [sqlite3_auto_extension()] calls.)^ 4363** 4364** ^This function disables automatic extensions in all threads. 4365*/ 4366void sqlite3_reset_auto_extension(void); 4367 4368/* 4369** The interface to the virtual-table mechanism is currently considered 4370** to be experimental. The interface might change in incompatible ways. 4371** If this is a problem for you, do not use the interface at this time. 4372** 4373** When the virtual-table mechanism stabilizes, we will declare the 4374** interface fixed, support it indefinitely, and remove this comment. 4375*/ 4376 4377/* 4378** Structures used by the virtual table interface 4379*/ 4380typedef struct sqlite3_vtab sqlite3_vtab; 4381typedef struct sqlite3_index_info sqlite3_index_info; 4382typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 4383typedef struct sqlite3_module sqlite3_module; 4384 4385/* 4386** CAPI3REF: Virtual Table Object 4387** KEYWORDS: sqlite3_module {virtual table module} 4388** 4389** This structure, sometimes called a a "virtual table module", 4390** defines the implementation of a [virtual tables]. 4391** This structure consists mostly of methods for the module. 4392** 4393** ^A virtual table module is created by filling in a persistent 4394** instance of this structure and passing a pointer to that instance 4395** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 4396** ^The registration remains valid until it is replaced by a different 4397** module or until the [database connection] closes. The content 4398** of this structure must not change while it is registered with 4399** any database connection. 4400*/ 4401struct sqlite3_module { 4402 int iVersion; 4403 int (*xCreate)(sqlite3*, void *pAux, 4404 int argc, const char *const*argv, 4405 sqlite3_vtab **ppVTab, char**); 4406 int (*xConnect)(sqlite3*, void *pAux, 4407 int argc, const char *const*argv, 4408 sqlite3_vtab **ppVTab, char**); 4409 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 4410 int (*xDisconnect)(sqlite3_vtab *pVTab); 4411 int (*xDestroy)(sqlite3_vtab *pVTab); 4412 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 4413 int (*xClose)(sqlite3_vtab_cursor*); 4414 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 4415 int argc, sqlite3_value **argv); 4416 int (*xNext)(sqlite3_vtab_cursor*); 4417 int (*xEof)(sqlite3_vtab_cursor*); 4418 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 4419 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 4420 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 4421 int (*xBegin)(sqlite3_vtab *pVTab); 4422 int (*xSync)(sqlite3_vtab *pVTab); 4423 int (*xCommit)(sqlite3_vtab *pVTab); 4424 int (*xRollback)(sqlite3_vtab *pVTab); 4425 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 4426 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 4427 void **ppArg); 4428 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 4429}; 4430 4431/* 4432** CAPI3REF: Virtual Table Indexing Information 4433** KEYWORDS: sqlite3_index_info 4434** 4435** The sqlite3_index_info structure and its substructures is used as part 4436** of the [virtual table] interface to 4437** pass information into and receive the reply from the [xBestIndex] 4438** method of a [virtual table module]. The fields under **Inputs** are the 4439** inputs to xBestIndex and are read-only. xBestIndex inserts its 4440** results into the **Outputs** fields. 4441** 4442** ^(The aConstraint[] array records WHERE clause constraints of the form: 4443** 4444** <blockquote>column OP expr</blockquote> 4445** 4446** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 4447** stored in aConstraint[].op using one of the 4448** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 4449** ^(The index of the column is stored in 4450** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 4451** expr on the right-hand side can be evaluated (and thus the constraint 4452** is usable) and false if it cannot.)^ 4453** 4454** ^The optimizer automatically inverts terms of the form "expr OP column" 4455** and makes other simplifications to the WHERE clause in an attempt to 4456** get as many WHERE clause terms into the form shown above as possible. 4457** ^The aConstraint[] array only reports WHERE clause terms that are 4458** relevant to the particular virtual table being queried. 4459** 4460** ^Information about the ORDER BY clause is stored in aOrderBy[]. 4461** ^Each term of aOrderBy records a column of the ORDER BY clause. 4462** 4463** The [xBestIndex] method must fill aConstraintUsage[] with information 4464** about what parameters to pass to xFilter. ^If argvIndex>0 then 4465** the right-hand side of the corresponding aConstraint[] is evaluated 4466** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 4467** is true, then the constraint is assumed to be fully handled by the 4468** virtual table and is not checked again by SQLite.)^ 4469** 4470** ^The idxNum and idxPtr values are recorded and passed into the 4471** [xFilter] method. 4472** ^[sqlite3_free()] is used to free idxPtr if and only if 4473** needToFreeIdxPtr is true. 4474** 4475** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 4476** the correct order to satisfy the ORDER BY clause so that no separate 4477** sorting step is required. 4478** 4479** ^The estimatedCost value is an estimate of the cost of doing the 4480** particular lookup. A full scan of a table with N entries should have 4481** a cost of N. A binary search of a table of N entries should have a 4482** cost of approximately log(N). 4483*/ 4484struct sqlite3_index_info { 4485 /* Inputs */ 4486 int nConstraint; /* Number of entries in aConstraint */ 4487 struct sqlite3_index_constraint { 4488 int iColumn; /* Column on left-hand side of constraint */ 4489 unsigned char op; /* Constraint operator */ 4490 unsigned char usable; /* True if this constraint is usable */ 4491 int iTermOffset; /* Used internally - xBestIndex should ignore */ 4492 } *aConstraint; /* Table of WHERE clause constraints */ 4493 int nOrderBy; /* Number of terms in the ORDER BY clause */ 4494 struct sqlite3_index_orderby { 4495 int iColumn; /* Column number */ 4496 unsigned char desc; /* True for DESC. False for ASC. */ 4497 } *aOrderBy; /* The ORDER BY clause */ 4498 /* Outputs */ 4499 struct sqlite3_index_constraint_usage { 4500 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 4501 unsigned char omit; /* Do not code a test for this constraint */ 4502 } *aConstraintUsage; 4503 int idxNum; /* Number used to identify the index */ 4504 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 4505 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 4506 int orderByConsumed; /* True if output is already ordered */ 4507 double estimatedCost; /* Estimated cost of using this index */ 4508}; 4509 4510/* 4511** CAPI3REF: Virtual Table Constraint Operator Codes 4512** 4513** These macros defined the allowed values for the 4514** [sqlite3_index_info].aConstraint[].op field. Each value represents 4515** an operator that is part of a constraint term in the wHERE clause of 4516** a query that uses a [virtual table]. 4517*/ 4518#define SQLITE_INDEX_CONSTRAINT_EQ 2 4519#define SQLITE_INDEX_CONSTRAINT_GT 4 4520#define SQLITE_INDEX_CONSTRAINT_LE 8 4521#define SQLITE_INDEX_CONSTRAINT_LT 16 4522#define SQLITE_INDEX_CONSTRAINT_GE 32 4523#define SQLITE_INDEX_CONSTRAINT_MATCH 64 4524 4525/* 4526** CAPI3REF: Register A Virtual Table Implementation 4527** 4528** ^These routines are used to register a new [virtual table module] name. 4529** ^Module names must be registered before 4530** creating a new [virtual table] using the module and before using a 4531** preexisting [virtual table] for the module. 4532** 4533** ^The module name is registered on the [database connection] specified 4534** by the first parameter. ^The name of the module is given by the 4535** second parameter. ^The third parameter is a pointer to 4536** the implementation of the [virtual table module]. ^The fourth 4537** parameter is an arbitrary client data pointer that is passed through 4538** into the [xCreate] and [xConnect] methods of the virtual table module 4539** when a new virtual table is be being created or reinitialized. 4540** 4541** ^The sqlite3_create_module_v2() interface has a fifth parameter which 4542** is a pointer to a destructor for the pClientData. ^SQLite will 4543** invoke the destructor function (if it is not NULL) when SQLite 4544** no longer needs the pClientData pointer. ^The sqlite3_create_module() 4545** interface is equivalent to sqlite3_create_module_v2() with a NULL 4546** destructor. 4547*/ 4548int sqlite3_create_module( 4549 sqlite3 *db, /* SQLite connection to register module with */ 4550 const char *zName, /* Name of the module */ 4551 const sqlite3_module *p, /* Methods for the module */ 4552 void *pClientData /* Client data for xCreate/xConnect */ 4553); 4554int sqlite3_create_module_v2( 4555 sqlite3 *db, /* SQLite connection to register module with */ 4556 const char *zName, /* Name of the module */ 4557 const sqlite3_module *p, /* Methods for the module */ 4558 void *pClientData, /* Client data for xCreate/xConnect */ 4559 void(*xDestroy)(void*) /* Module destructor function */ 4560); 4561 4562/* 4563** CAPI3REF: Virtual Table Instance Object 4564** KEYWORDS: sqlite3_vtab 4565** 4566** Every [virtual table module] implementation uses a subclass 4567** of this object to describe a particular instance 4568** of the [virtual table]. Each subclass will 4569** be tailored to the specific needs of the module implementation. 4570** The purpose of this superclass is to define certain fields that are 4571** common to all module implementations. 4572** 4573** ^Virtual tables methods can set an error message by assigning a 4574** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 4575** take care that any prior string is freed by a call to [sqlite3_free()] 4576** prior to assigning a new string to zErrMsg. ^After the error message 4577** is delivered up to the client application, the string will be automatically 4578** freed by sqlite3_free() and the zErrMsg field will be zeroed. 4579*/ 4580struct sqlite3_vtab { 4581 const sqlite3_module *pModule; /* The module for this virtual table */ 4582 int nRef; /* NO LONGER USED */ 4583 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 4584 /* Virtual table implementations will typically add additional fields */ 4585}; 4586 4587/* 4588** CAPI3REF: Virtual Table Cursor Object 4589** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 4590** 4591** Every [virtual table module] implementation uses a subclass of the 4592** following structure to describe cursors that point into the 4593** [virtual table] and are used 4594** to loop through the virtual table. Cursors are created using the 4595** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 4596** by the [sqlite3_module.xClose | xClose] method. Cursors are used 4597** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 4598** of the module. Each module implementation will define 4599** the content of a cursor structure to suit its own needs. 4600** 4601** This superclass exists in order to define fields of the cursor that 4602** are common to all implementations. 4603*/ 4604struct sqlite3_vtab_cursor { 4605 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 4606 /* Virtual table implementations will typically add additional fields */ 4607}; 4608 4609/* 4610** CAPI3REF: Declare The Schema Of A Virtual Table 4611** 4612** ^The [xCreate] and [xConnect] methods of a 4613** [virtual table module] call this interface 4614** to declare the format (the names and datatypes of the columns) of 4615** the virtual tables they implement. 4616*/ 4617int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 4618 4619/* 4620** CAPI3REF: Overload A Function For A Virtual Table 4621** 4622** ^(Virtual tables can provide alternative implementations of functions 4623** using the [xFindFunction] method of the [virtual table module]. 4624** But global versions of those functions 4625** must exist in order to be overloaded.)^ 4626** 4627** ^(This API makes sure a global version of a function with a particular 4628** name and number of parameters exists. If no such function exists 4629** before this API is called, a new function is created.)^ ^The implementation 4630** of the new function always causes an exception to be thrown. So 4631** the new function is not good for anything by itself. Its only 4632** purpose is to be a placeholder function that can be overloaded 4633** by a [virtual table]. 4634*/ 4635int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 4636 4637/* 4638** The interface to the virtual-table mechanism defined above (back up 4639** to a comment remarkably similar to this one) is currently considered 4640** to be experimental. The interface might change in incompatible ways. 4641** If this is a problem for you, do not use the interface at this time. 4642** 4643** When the virtual-table mechanism stabilizes, we will declare the 4644** interface fixed, support it indefinitely, and remove this comment. 4645*/ 4646 4647/* 4648** CAPI3REF: A Handle To An Open BLOB 4649** KEYWORDS: {BLOB handle} {BLOB handles} 4650** 4651** An instance of this object represents an open BLOB on which 4652** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 4653** ^Objects of this type are created by [sqlite3_blob_open()] 4654** and destroyed by [sqlite3_blob_close()]. 4655** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 4656** can be used to read or write small subsections of the BLOB. 4657** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 4658*/ 4659typedef struct sqlite3_blob sqlite3_blob; 4660 4661/* 4662** CAPI3REF: Open A BLOB For Incremental I/O 4663** 4664** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 4665** in row iRow, column zColumn, table zTable in database zDb; 4666** in other words, the same BLOB that would be selected by: 4667** 4668** <pre> 4669** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 4670** </pre>)^ 4671** 4672** ^If the flags parameter is non-zero, then the BLOB is opened for read 4673** and write access. ^If it is zero, the BLOB is opened for read access. 4674** ^It is not possible to open a column that is part of an index or primary 4675** key for writing. ^If [foreign key constraints] are enabled, it is 4676** not possible to open a column that is part of a [child key] for writing. 4677** 4678** ^Note that the database name is not the filename that contains 4679** the database but rather the symbolic name of the database that 4680** appears after the AS keyword when the database is connected using [ATTACH]. 4681** ^For the main database file, the database name is "main". 4682** ^For TEMP tables, the database name is "temp". 4683** 4684** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written 4685** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set 4686** to be a null pointer.)^ 4687** ^This function sets the [database connection] error code and message 4688** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related 4689** functions. ^Note that the *ppBlob variable is always initialized in a 4690** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob 4691** regardless of the success or failure of this routine. 4692** 4693** ^(If the row that a BLOB handle points to is modified by an 4694** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 4695** then the BLOB handle is marked as "expired". 4696** This is true if any column of the row is changed, even a column 4697** other than the one the BLOB handle is open on.)^ 4698** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 4699** a expired BLOB handle fail with an return code of [SQLITE_ABORT]. 4700** ^(Changes written into a BLOB prior to the BLOB expiring are not 4701** rolled back by the expiration of the BLOB. Such changes will eventually 4702** commit if the transaction continues to completion.)^ 4703** 4704** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 4705** the opened blob. ^The size of a blob may not be changed by this 4706** interface. Use the [UPDATE] SQL command to change the size of a 4707** blob. 4708** 4709** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 4710** and the built-in [zeroblob] SQL function can be used, if desired, 4711** to create an empty, zero-filled blob in which to read or write using 4712** this interface. 4713** 4714** To avoid a resource leak, every open [BLOB handle] should eventually 4715** be released by a call to [sqlite3_blob_close()]. 4716*/ 4717int sqlite3_blob_open( 4718 sqlite3*, 4719 const char *zDb, 4720 const char *zTable, 4721 const char *zColumn, 4722 sqlite3_int64 iRow, 4723 int flags, 4724 sqlite3_blob **ppBlob 4725); 4726 4727/* 4728** CAPI3REF: Close A BLOB Handle 4729** 4730** ^Closes an open [BLOB handle]. 4731** 4732** ^Closing a BLOB shall cause the current transaction to commit 4733** if there are no other BLOBs, no pending prepared statements, and the 4734** database connection is in [autocommit mode]. 4735** ^If any writes were made to the BLOB, they might be held in cache 4736** until the close operation if they will fit. 4737** 4738** ^(Closing the BLOB often forces the changes 4739** out to disk and so if any I/O errors occur, they will likely occur 4740** at the time when the BLOB is closed. Any errors that occur during 4741** closing are reported as a non-zero return value.)^ 4742** 4743** ^(The BLOB is closed unconditionally. Even if this routine returns 4744** an error code, the BLOB is still closed.)^ 4745** 4746** ^Calling this routine with a null pointer (such as would be returned 4747** by a failed call to [sqlite3_blob_open()]) is a harmless no-op. 4748*/ 4749int sqlite3_blob_close(sqlite3_blob *); 4750 4751/* 4752** CAPI3REF: Return The Size Of An Open BLOB 4753** 4754** ^Returns the size in bytes of the BLOB accessible via the 4755** successfully opened [BLOB handle] in its only argument. ^The 4756** incremental blob I/O routines can only read or overwriting existing 4757** blob content; they cannot change the size of a blob. 4758** 4759** This routine only works on a [BLOB handle] which has been created 4760** by a prior successful call to [sqlite3_blob_open()] and which has not 4761** been closed by [sqlite3_blob_close()]. Passing any other pointer in 4762** to this routine results in undefined and probably undesirable behavior. 4763*/ 4764int sqlite3_blob_bytes(sqlite3_blob *); 4765 4766/* 4767** CAPI3REF: Read Data From A BLOB Incrementally 4768** 4769** ^(This function is used to read data from an open [BLOB handle] into a 4770** caller-supplied buffer. N bytes of data are copied into buffer Z 4771** from the open BLOB, starting at offset iOffset.)^ 4772** 4773** ^If offset iOffset is less than N bytes from the end of the BLOB, 4774** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 4775** less than zero, [SQLITE_ERROR] is returned and no data is read. 4776** ^The size of the blob (and hence the maximum value of N+iOffset) 4777** can be determined using the [sqlite3_blob_bytes()] interface. 4778** 4779** ^An attempt to read from an expired [BLOB handle] fails with an 4780** error code of [SQLITE_ABORT]. 4781** 4782** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 4783** Otherwise, an [error code] or an [extended error code] is returned.)^ 4784** 4785** This routine only works on a [BLOB handle] which has been created 4786** by a prior successful call to [sqlite3_blob_open()] and which has not 4787** been closed by [sqlite3_blob_close()]. Passing any other pointer in 4788** to this routine results in undefined and probably undesirable behavior. 4789** 4790** See also: [sqlite3_blob_write()]. 4791*/ 4792int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 4793 4794/* 4795** CAPI3REF: Write Data Into A BLOB Incrementally 4796** 4797** ^This function is used to write data into an open [BLOB handle] from a 4798** caller-supplied buffer. ^N bytes of data are copied from the buffer Z 4799** into the open BLOB, starting at offset iOffset. 4800** 4801** ^If the [BLOB handle] passed as the first argument was not opened for 4802** writing (the flags parameter to [sqlite3_blob_open()] was zero), 4803** this function returns [SQLITE_READONLY]. 4804** 4805** ^This function may only modify the contents of the BLOB; it is 4806** not possible to increase the size of a BLOB using this API. 4807** ^If offset iOffset is less than N bytes from the end of the BLOB, 4808** [SQLITE_ERROR] is returned and no data is written. ^If N is 4809** less than zero [SQLITE_ERROR] is returned and no data is written. 4810** The size of the BLOB (and hence the maximum value of N+iOffset) 4811** can be determined using the [sqlite3_blob_bytes()] interface. 4812** 4813** ^An attempt to write to an expired [BLOB handle] fails with an 4814** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 4815** before the [BLOB handle] expired are not rolled back by the 4816** expiration of the handle, though of course those changes might 4817** have been overwritten by the statement that expired the BLOB handle 4818** or by other independent statements. 4819** 4820** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 4821** Otherwise, an [error code] or an [extended error code] is returned.)^ 4822** 4823** This routine only works on a [BLOB handle] which has been created 4824** by a prior successful call to [sqlite3_blob_open()] and which has not 4825** been closed by [sqlite3_blob_close()]. Passing any other pointer in 4826** to this routine results in undefined and probably undesirable behavior. 4827** 4828** See also: [sqlite3_blob_read()]. 4829*/ 4830int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 4831 4832/* 4833** CAPI3REF: Virtual File System Objects 4834** 4835** A virtual filesystem (VFS) is an [sqlite3_vfs] object 4836** that SQLite uses to interact 4837** with the underlying operating system. Most SQLite builds come with a 4838** single default VFS that is appropriate for the host computer. 4839** New VFSes can be registered and existing VFSes can be unregistered. 4840** The following interfaces are provided. 4841** 4842** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 4843** ^Names are case sensitive. 4844** ^Names are zero-terminated UTF-8 strings. 4845** ^If there is no match, a NULL pointer is returned. 4846** ^If zVfsName is NULL then the default VFS is returned. 4847** 4848** ^New VFSes are registered with sqlite3_vfs_register(). 4849** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 4850** ^The same VFS can be registered multiple times without injury. 4851** ^To make an existing VFS into the default VFS, register it again 4852** with the makeDflt flag set. If two different VFSes with the 4853** same name are registered, the behavior is undefined. If a 4854** VFS is registered with a name that is NULL or an empty string, 4855** then the behavior is undefined. 4856** 4857** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 4858** ^(If the default VFS is unregistered, another VFS is chosen as 4859** the default. The choice for the new VFS is arbitrary.)^ 4860*/ 4861sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 4862int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 4863int sqlite3_vfs_unregister(sqlite3_vfs*); 4864 4865/* 4866** CAPI3REF: Mutexes 4867** 4868** The SQLite core uses these routines for thread 4869** synchronization. Though they are intended for internal 4870** use by SQLite, code that links against SQLite is 4871** permitted to use any of these routines. 4872** 4873** The SQLite source code contains multiple implementations 4874** of these mutex routines. An appropriate implementation 4875** is selected automatically at compile-time. ^(The following 4876** implementations are available in the SQLite core: 4877** 4878** <ul> 4879** <li> SQLITE_MUTEX_OS2 4880** <li> SQLITE_MUTEX_PTHREAD 4881** <li> SQLITE_MUTEX_W32 4882** <li> SQLITE_MUTEX_NOOP 4883** </ul>)^ 4884** 4885** ^The SQLITE_MUTEX_NOOP implementation is a set of routines 4886** that does no real locking and is appropriate for use in 4887** a single-threaded application. ^The SQLITE_MUTEX_OS2, 4888** SQLITE_MUTEX_PTHREAD, and SQLITE_MUTEX_W32 implementations 4889** are appropriate for use on OS/2, Unix, and Windows. 4890** 4891** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 4892** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 4893** implementation is included with the library. In this case the 4894** application must supply a custom mutex implementation using the 4895** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 4896** before calling sqlite3_initialize() or any other public sqlite3_ 4897** function that calls sqlite3_initialize().)^ 4898** 4899** ^The sqlite3_mutex_alloc() routine allocates a new 4900** mutex and returns a pointer to it. ^If it returns NULL 4901** that means that a mutex could not be allocated. ^SQLite 4902** will unwind its stack and return an error. ^(The argument 4903** to sqlite3_mutex_alloc() is one of these integer constants: 4904** 4905** <ul> 4906** <li> SQLITE_MUTEX_FAST 4907** <li> SQLITE_MUTEX_RECURSIVE 4908** <li> SQLITE_MUTEX_STATIC_MASTER 4909** <li> SQLITE_MUTEX_STATIC_MEM 4910** <li> SQLITE_MUTEX_STATIC_MEM2 4911** <li> SQLITE_MUTEX_STATIC_PRNG 4912** <li> SQLITE_MUTEX_STATIC_LRU 4913** <li> SQLITE_MUTEX_STATIC_LRU2 4914** </ul>)^ 4915** 4916** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 4917** cause sqlite3_mutex_alloc() to create 4918** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 4919** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 4920** The mutex implementation does not need to make a distinction 4921** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 4922** not want to. ^SQLite will only request a recursive mutex in 4923** cases where it really needs one. ^If a faster non-recursive mutex 4924** implementation is available on the host platform, the mutex subsystem 4925** might return such a mutex in response to SQLITE_MUTEX_FAST. 4926** 4927** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 4928** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 4929** a pointer to a static preexisting mutex. ^Six static mutexes are 4930** used by the current version of SQLite. Future versions of SQLite 4931** may add additional static mutexes. Static mutexes are for internal 4932** use by SQLite only. Applications that use SQLite mutexes should 4933** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 4934** SQLITE_MUTEX_RECURSIVE. 4935** 4936** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 4937** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 4938** returns a different mutex on every call. ^But for the static 4939** mutex types, the same mutex is returned on every call that has 4940** the same type number. 4941** 4942** ^The sqlite3_mutex_free() routine deallocates a previously 4943** allocated dynamic mutex. ^SQLite is careful to deallocate every 4944** dynamic mutex that it allocates. The dynamic mutexes must not be in 4945** use when they are deallocated. Attempting to deallocate a static 4946** mutex results in undefined behavior. ^SQLite never deallocates 4947** a static mutex. 4948** 4949** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 4950** to enter a mutex. ^If another thread is already within the mutex, 4951** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 4952** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 4953** upon successful entry. ^(Mutexes created using 4954** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 4955** In such cases the, 4956** mutex must be exited an equal number of times before another thread 4957** can enter.)^ ^(If the same thread tries to enter any other 4958** kind of mutex more than once, the behavior is undefined. 4959** SQLite will never exhibit 4960** such behavior in its own use of mutexes.)^ 4961** 4962** ^(Some systems (for example, Windows 95) do not support the operation 4963** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 4964** will always return SQLITE_BUSY. The SQLite core only ever uses 4965** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^ 4966** 4967** ^The sqlite3_mutex_leave() routine exits a mutex that was 4968** previously entered by the same thread. ^(The behavior 4969** is undefined if the mutex is not currently entered by the 4970** calling thread or is not currently allocated. SQLite will 4971** never do either.)^ 4972** 4973** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 4974** sqlite3_mutex_leave() is a NULL pointer, then all three routines 4975** behave as no-ops. 4976** 4977** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 4978*/ 4979sqlite3_mutex *sqlite3_mutex_alloc(int); 4980void sqlite3_mutex_free(sqlite3_mutex*); 4981void sqlite3_mutex_enter(sqlite3_mutex*); 4982int sqlite3_mutex_try(sqlite3_mutex*); 4983void sqlite3_mutex_leave(sqlite3_mutex*); 4984 4985/* 4986** CAPI3REF: Mutex Methods Object 4987** 4988** An instance of this structure defines the low-level routines 4989** used to allocate and use mutexes. 4990** 4991** Usually, the default mutex implementations provided by SQLite are 4992** sufficient, however the user has the option of substituting a custom 4993** implementation for specialized deployments or systems for which SQLite 4994** does not provide a suitable implementation. In this case, the user 4995** creates and populates an instance of this structure to pass 4996** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 4997** Additionally, an instance of this structure can be used as an 4998** output variable when querying the system for the current mutex 4999** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 5000** 5001** ^The xMutexInit method defined by this structure is invoked as 5002** part of system initialization by the sqlite3_initialize() function. 5003** ^The xMutexInit routine is called by SQLite exactly once for each 5004** effective call to [sqlite3_initialize()]. 5005** 5006** ^The xMutexEnd method defined by this structure is invoked as 5007** part of system shutdown by the sqlite3_shutdown() function. The 5008** implementation of this method is expected to release all outstanding 5009** resources obtained by the mutex methods implementation, especially 5010** those obtained by the xMutexInit method. ^The xMutexEnd() 5011** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 5012** 5013** ^(The remaining seven methods defined by this structure (xMutexAlloc, 5014** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 5015** xMutexNotheld) implement the following interfaces (respectively): 5016** 5017** <ul> 5018** <li> [sqlite3_mutex_alloc()] </li> 5019** <li> [sqlite3_mutex_free()] </li> 5020** <li> [sqlite3_mutex_enter()] </li> 5021** <li> [sqlite3_mutex_try()] </li> 5022** <li> [sqlite3_mutex_leave()] </li> 5023** <li> [sqlite3_mutex_held()] </li> 5024** <li> [sqlite3_mutex_notheld()] </li> 5025** </ul>)^ 5026** 5027** The only difference is that the public sqlite3_XXX functions enumerated 5028** above silently ignore any invocations that pass a NULL pointer instead 5029** of a valid mutex handle. The implementations of the methods defined 5030** by this structure are not required to handle this case, the results 5031** of passing a NULL pointer instead of a valid mutex handle are undefined 5032** (i.e. it is acceptable to provide an implementation that segfaults if 5033** it is passed a NULL pointer). 5034** 5035** The xMutexInit() method must be threadsafe. ^It must be harmless to 5036** invoke xMutexInit() multiple times within the same process and without 5037** intervening calls to xMutexEnd(). Second and subsequent calls to 5038** xMutexInit() must be no-ops. 5039** 5040** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 5041** and its associates). ^Similarly, xMutexAlloc() must not use SQLite memory 5042** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 5043** memory allocation for a fast or recursive mutex. 5044** 5045** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 5046** called, but only if the prior call to xMutexInit returned SQLITE_OK. 5047** If xMutexInit fails in any way, it is expected to clean up after itself 5048** prior to returning. 5049*/ 5050typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 5051struct sqlite3_mutex_methods { 5052 int (*xMutexInit)(void); 5053 int (*xMutexEnd)(void); 5054 sqlite3_mutex *(*xMutexAlloc)(int); 5055 void (*xMutexFree)(sqlite3_mutex *); 5056 void (*xMutexEnter)(sqlite3_mutex *); 5057 int (*xMutexTry)(sqlite3_mutex *); 5058 void (*xMutexLeave)(sqlite3_mutex *); 5059 int (*xMutexHeld)(sqlite3_mutex *); 5060 int (*xMutexNotheld)(sqlite3_mutex *); 5061}; 5062 5063/* 5064** CAPI3REF: Mutex Verification Routines 5065** 5066** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 5067** are intended for use inside assert() statements. ^The SQLite core 5068** never uses these routines except inside an assert() and applications 5069** are advised to follow the lead of the core. ^The SQLite core only 5070** provides implementations for these routines when it is compiled 5071** with the SQLITE_DEBUG flag. ^External mutex implementations 5072** are only required to provide these routines if SQLITE_DEBUG is 5073** defined and if NDEBUG is not defined. 5074** 5075** ^These routines should return true if the mutex in their argument 5076** is held or not held, respectively, by the calling thread. 5077** 5078** ^The implementation is not required to provided versions of these 5079** routines that actually work. If the implementation does not provide working 5080** versions of these routines, it should at least provide stubs that always 5081** return true so that one does not get spurious assertion failures. 5082** 5083** ^If the argument to sqlite3_mutex_held() is a NULL pointer then 5084** the routine should return 1. This seems counter-intuitive since 5085** clearly the mutex cannot be held if it does not exist. But the 5086** the reason the mutex does not exist is because the build is not 5087** using mutexes. And we do not want the assert() containing the 5088** call to sqlite3_mutex_held() to fail, so a non-zero return is 5089** the appropriate thing to do. ^The sqlite3_mutex_notheld() 5090** interface should also return 1 when given a NULL pointer. 5091*/ 5092#ifndef NDEBUG 5093int sqlite3_mutex_held(sqlite3_mutex*); 5094int sqlite3_mutex_notheld(sqlite3_mutex*); 5095#endif 5096 5097/* 5098** CAPI3REF: Mutex Types 5099** 5100** The [sqlite3_mutex_alloc()] interface takes a single argument 5101** which is one of these integer constants. 5102** 5103** The set of static mutexes may change from one SQLite release to the 5104** next. Applications that override the built-in mutex logic must be 5105** prepared to accommodate additional static mutexes. 5106*/ 5107#define SQLITE_MUTEX_FAST 0 5108#define SQLITE_MUTEX_RECURSIVE 1 5109#define SQLITE_MUTEX_STATIC_MASTER 2 5110#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 5111#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 5112#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 5113#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ 5114#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 5115#define SQLITE_MUTEX_STATIC_LRU2 7 /* lru page list */ 5116 5117/* 5118** CAPI3REF: Retrieve the mutex for a database connection 5119** 5120** ^This interface returns a pointer the [sqlite3_mutex] object that 5121** serializes access to the [database connection] given in the argument 5122** when the [threading mode] is Serialized. 5123** ^If the [threading mode] is Single-thread or Multi-thread then this 5124** routine returns a NULL pointer. 5125*/ 5126sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 5127 5128/* 5129** CAPI3REF: Low-Level Control Of Database Files 5130** 5131** ^The [sqlite3_file_control()] interface makes a direct call to the 5132** xFileControl method for the [sqlite3_io_methods] object associated 5133** with a particular database identified by the second argument. ^The 5134** name of the database "main" for the main database or "temp" for the 5135** TEMP database, or the name that appears after the AS keyword for 5136** databases that are added using the [ATTACH] SQL command. 5137** ^A NULL pointer can be used in place of "main" to refer to the 5138** main database file. 5139** ^The third and fourth parameters to this routine 5140** are passed directly through to the second and third parameters of 5141** the xFileControl method. ^The return value of the xFileControl 5142** method becomes the return value of this routine. 5143** 5144** ^If the second parameter (zDbName) does not match the name of any 5145** open database file, then SQLITE_ERROR is returned. ^This error 5146** code is not remembered and will not be recalled by [sqlite3_errcode()] 5147** or [sqlite3_errmsg()]. The underlying xFileControl method might 5148** also return SQLITE_ERROR. There is no way to distinguish between 5149** an incorrect zDbName and an SQLITE_ERROR return from the underlying 5150** xFileControl method. 5151** 5152** See also: [SQLITE_FCNTL_LOCKSTATE] 5153*/ 5154int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 5155 5156/* 5157** CAPI3REF: Testing Interface 5158** 5159** ^The sqlite3_test_control() interface is used to read out internal 5160** state of SQLite and to inject faults into SQLite for testing 5161** purposes. ^The first parameter is an operation code that determines 5162** the number, meaning, and operation of all subsequent parameters. 5163** 5164** This interface is not for use by applications. It exists solely 5165** for verifying the correct operation of the SQLite library. Depending 5166** on how the SQLite library is compiled, this interface might not exist. 5167** 5168** The details of the operation codes, their meanings, the parameters 5169** they take, and what they do are all subject to change without notice. 5170** Unlike most of the SQLite API, this function is not guaranteed to 5171** operate consistently from one release to the next. 5172*/ 5173int sqlite3_test_control(int op, ...); 5174 5175/* 5176** CAPI3REF: Testing Interface Operation Codes 5177** 5178** These constants are the valid operation code parameters used 5179** as the first argument to [sqlite3_test_control()]. 5180** 5181** These parameters and their meanings are subject to change 5182** without notice. These values are for testing purposes only. 5183** Applications should not use any of these parameters or the 5184** [sqlite3_test_control()] interface. 5185*/ 5186#define SQLITE_TESTCTRL_FIRST 5 5187#define SQLITE_TESTCTRL_PRNG_SAVE 5 5188#define SQLITE_TESTCTRL_PRNG_RESTORE 6 5189#define SQLITE_TESTCTRL_PRNG_RESET 7 5190#define SQLITE_TESTCTRL_BITVEC_TEST 8 5191#define SQLITE_TESTCTRL_FAULT_INSTALL 9 5192#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 5193#define SQLITE_TESTCTRL_PENDING_BYTE 11 5194#define SQLITE_TESTCTRL_ASSERT 12 5195#define SQLITE_TESTCTRL_ALWAYS 13 5196#define SQLITE_TESTCTRL_RESERVE 14 5197#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 5198#define SQLITE_TESTCTRL_ISKEYWORD 16 5199#define SQLITE_TESTCTRL_PGHDRSZ 17 5200#define SQLITE_TESTCTRL_SCRATCHMALLOC 18 5201#define SQLITE_TESTCTRL_LAST 18 5202 5203/* 5204** CAPI3REF: SQLite Runtime Status 5205** 5206** ^This interface is used to retrieve runtime status information 5207** about the performance of SQLite, and optionally to reset various 5208** highwater marks. ^The first argument is an integer code for 5209** the specific parameter to measure. ^(Recognized integer codes 5210** are of the form [SQLITE_STATUS_MEMORY_USED | SQLITE_STATUS_...].)^ 5211** ^The current value of the parameter is returned into *pCurrent. 5212** ^The highest recorded value is returned in *pHighwater. ^If the 5213** resetFlag is true, then the highest record value is reset after 5214** *pHighwater is written. ^(Some parameters do not record the highest 5215** value. For those parameters 5216** nothing is written into *pHighwater and the resetFlag is ignored.)^ 5217** ^(Other parameters record only the highwater mark and not the current 5218** value. For these latter parameters nothing is written into *pCurrent.)^ 5219** 5220** ^The sqlite3_status() routine returns SQLITE_OK on success and a 5221** non-zero [error code] on failure. 5222** 5223** This routine is threadsafe but is not atomic. This routine can be 5224** called while other threads are running the same or different SQLite 5225** interfaces. However the values returned in *pCurrent and 5226** *pHighwater reflect the status of SQLite at different points in time 5227** and it is possible that another thread might change the parameter 5228** in between the times when *pCurrent and *pHighwater are written. 5229** 5230** See also: [sqlite3_db_status()] 5231*/ 5232int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 5233 5234 5235/* 5236** CAPI3REF: Status Parameters 5237** 5238** These integer constants designate various run-time status parameters 5239** that can be returned by [sqlite3_status()]. 5240** 5241** <dl> 5242** ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 5243** <dd>This parameter is the current amount of memory checked out 5244** using [sqlite3_malloc()], either directly or indirectly. The 5245** figure includes calls made to [sqlite3_malloc()] by the application 5246** and internal memory usage by the SQLite library. Scratch memory 5247** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 5248** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 5249** this parameter. The amount returned is the sum of the allocation 5250** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 5251** 5252** ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 5253** <dd>This parameter records the largest memory allocation request 5254** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 5255** internal equivalents). Only the value returned in the 5256** *pHighwater parameter to [sqlite3_status()] is of interest. 5257** The value written into the *pCurrent parameter is undefined.</dd>)^ 5258** 5259** ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 5260** <dd>This parameter records the number of separate memory allocations.</dd>)^ 5261** 5262** ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 5263** <dd>This parameter returns the number of pages used out of the 5264** [pagecache memory allocator] that was configured using 5265** [SQLITE_CONFIG_PAGECACHE]. The 5266** value returned is in pages, not in bytes.</dd>)^ 5267** 5268** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 5269** <dd>This parameter returns the number of bytes of page cache 5270** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 5271** buffer and where forced to overflow to [sqlite3_malloc()]. The 5272** returned value includes allocations that overflowed because they 5273** where too large (they were larger than the "sz" parameter to 5274** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 5275** no space was left in the page cache.</dd>)^ 5276** 5277** ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 5278** <dd>This parameter records the largest memory allocation request 5279** handed to [pagecache memory allocator]. Only the value returned in the 5280** *pHighwater parameter to [sqlite3_status()] is of interest. 5281** The value written into the *pCurrent parameter is undefined.</dd>)^ 5282** 5283** ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt> 5284** <dd>This parameter returns the number of allocations used out of the 5285** [scratch memory allocator] configured using 5286** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 5287** in bytes. Since a single thread may only have one scratch allocation 5288** outstanding at time, this parameter also reports the number of threads 5289** using scratch memory at the same time.</dd>)^ 5290** 5291** ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 5292** <dd>This parameter returns the number of bytes of scratch memory 5293** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH] 5294** buffer and where forced to overflow to [sqlite3_malloc()]. The values 5295** returned include overflows because the requested allocation was too 5296** larger (that is, because the requested allocation was larger than the 5297** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 5298** slots were available. 5299** </dd>)^ 5300** 5301** ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 5302** <dd>This parameter records the largest memory allocation request 5303** handed to [scratch memory allocator]. Only the value returned in the 5304** *pHighwater parameter to [sqlite3_status()] is of interest. 5305** The value written into the *pCurrent parameter is undefined.</dd>)^ 5306** 5307** ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 5308** <dd>This parameter records the deepest parser stack. It is only 5309** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 5310** </dl> 5311** 5312** New status parameters may be added from time to time. 5313*/ 5314#define SQLITE_STATUS_MEMORY_USED 0 5315#define SQLITE_STATUS_PAGECACHE_USED 1 5316#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 5317#define SQLITE_STATUS_SCRATCH_USED 3 5318#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 5319#define SQLITE_STATUS_MALLOC_SIZE 5 5320#define SQLITE_STATUS_PARSER_STACK 6 5321#define SQLITE_STATUS_PAGECACHE_SIZE 7 5322#define SQLITE_STATUS_SCRATCH_SIZE 8 5323#define SQLITE_STATUS_MALLOC_COUNT 9 5324 5325/* 5326** CAPI3REF: Database Connection Status 5327** 5328** ^This interface is used to retrieve runtime status information 5329** about a single [database connection]. ^The first argument is the 5330** database connection object to be interrogated. ^The second argument 5331** is an integer constant, taken from the set of 5332** [SQLITE_DBSTATUS_LOOKASIDE_USED | SQLITE_DBSTATUS_*] macros, that 5333** determines the parameter to interrogate. The set of 5334** [SQLITE_DBSTATUS_LOOKASIDE_USED | SQLITE_DBSTATUS_*] macros is likely 5335** to grow in future releases of SQLite. 5336** 5337** ^The current value of the requested parameter is written into *pCur 5338** and the highest instantaneous value is written into *pHiwtr. ^If 5339** the resetFlg is true, then the highest instantaneous value is 5340** reset back down to the current value. 5341** 5342** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 5343** non-zero [error code] on failure. 5344** 5345** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 5346*/ 5347int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 5348 5349/* 5350** CAPI3REF: Status Parameters for database connections 5351** 5352** These constants are the available integer "verbs" that can be passed as 5353** the second argument to the [sqlite3_db_status()] interface. 5354** 5355** New verbs may be added in future releases of SQLite. Existing verbs 5356** might be discontinued. Applications should check the return code from 5357** [sqlite3_db_status()] to make sure that the call worked. 5358** The [sqlite3_db_status()] interface will return a non-zero error code 5359** if a discontinued or unsupported verb is invoked. 5360** 5361** <dl> 5362** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 5363** <dd>This parameter returns the number of lookaside memory slots currently 5364** checked out.</dd>)^ 5365** 5366** ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 5367** <dd>This parameter returns the approximate number of of bytes of heap 5368** memory used by all pager caches associated with the database connection.)^ 5369** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 5370** 5371** ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 5372** <dd>This parameter returns the approximate number of of bytes of heap 5373** memory used to store the schema for all databases associated 5374** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 5375** ^The full amount of memory used by the schemas is reported, even if the 5376** schema memory is shared with other database connections due to 5377** [shared cache mode] being enabled. 5378** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 5379** 5380** ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 5381** <dd>This parameter returns the approximate number of of bytes of heap 5382** and lookaside memory used by all prepared statements associated with 5383** the database connection.)^ 5384** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 5385** </dd> 5386** </dl> 5387*/ 5388#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 5389#define SQLITE_DBSTATUS_CACHE_USED 1 5390#define SQLITE_DBSTATUS_SCHEMA_USED 2 5391#define SQLITE_DBSTATUS_STMT_USED 3 5392#define SQLITE_DBSTATUS_MAX 3 /* Largest defined DBSTATUS */ 5393 5394 5395/* 5396** CAPI3REF: Prepared Statement Status 5397** 5398** ^(Each prepared statement maintains various 5399** [SQLITE_STMTSTATUS_SORT | counters] that measure the number 5400** of times it has performed specific operations.)^ These counters can 5401** be used to monitor the performance characteristics of the prepared 5402** statements. For example, if the number of table steps greatly exceeds 5403** the number of table searches or result rows, that would tend to indicate 5404** that the prepared statement is using a full table scan rather than 5405** an index. 5406** 5407** ^(This interface is used to retrieve and reset counter values from 5408** a [prepared statement]. The first argument is the prepared statement 5409** object to be interrogated. The second argument 5410** is an integer code for a specific [SQLITE_STMTSTATUS_SORT | counter] 5411** to be interrogated.)^ 5412** ^The current value of the requested counter is returned. 5413** ^If the resetFlg is true, then the counter is reset to zero after this 5414** interface call returns. 5415** 5416** See also: [sqlite3_status()] and [sqlite3_db_status()]. 5417*/ 5418int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 5419 5420/* 5421** CAPI3REF: Status Parameters for prepared statements 5422** 5423** These preprocessor macros define integer codes that name counter 5424** values associated with the [sqlite3_stmt_status()] interface. 5425** The meanings of the various counters are as follows: 5426** 5427** <dl> 5428** <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 5429** <dd>^This is the number of times that SQLite has stepped forward in 5430** a table as part of a full table scan. Large numbers for this counter 5431** may indicate opportunities for performance improvement through 5432** careful use of indices.</dd> 5433** 5434** <dt>SQLITE_STMTSTATUS_SORT</dt> 5435** <dd>^This is the number of sort operations that have occurred. 5436** A non-zero value in this counter may indicate an opportunity to 5437** improvement performance through careful use of indices.</dd> 5438** 5439** <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 5440** <dd>^This is the number of rows inserted into transient indices that 5441** were created automatically in order to help joins run faster. 5442** A non-zero value in this counter may indicate an opportunity to 5443** improvement performance by adding permanent indices that do not 5444** need to be reinitialized each time the statement is run.</dd> 5445** 5446** </dl> 5447*/ 5448#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 5449#define SQLITE_STMTSTATUS_SORT 2 5450#define SQLITE_STMTSTATUS_AUTOINDEX 3 5451 5452/* 5453** CAPI3REF: Custom Page Cache Object 5454** 5455** The sqlite3_pcache type is opaque. It is implemented by 5456** the pluggable module. The SQLite core has no knowledge of 5457** its size or internal structure and never deals with the 5458** sqlite3_pcache object except by holding and passing pointers 5459** to the object. 5460** 5461** See [sqlite3_pcache_methods] for additional information. 5462*/ 5463typedef struct sqlite3_pcache sqlite3_pcache; 5464 5465/* 5466** CAPI3REF: Application Defined Page Cache. 5467** KEYWORDS: {page cache} 5468** 5469** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE], ...) interface can 5470** register an alternative page cache implementation by passing in an 5471** instance of the sqlite3_pcache_methods structure.)^ 5472** In many applications, most of the heap memory allocated by 5473** SQLite is used for the page cache. 5474** By implementing a 5475** custom page cache using this API, an application can better control 5476** the amount of memory consumed by SQLite, the way in which 5477** that memory is allocated and released, and the policies used to 5478** determine exactly which parts of a database file are cached and for 5479** how long. 5480** 5481** The alternative page cache mechanism is an 5482** extreme measure that is only needed by the most demanding applications. 5483** The built-in page cache is recommended for most uses. 5484** 5485** ^(The contents of the sqlite3_pcache_methods structure are copied to an 5486** internal buffer by SQLite within the call to [sqlite3_config]. Hence 5487** the application may discard the parameter after the call to 5488** [sqlite3_config()] returns.)^ 5489** 5490** ^(The xInit() method is called once for each effective 5491** call to [sqlite3_initialize()])^ 5492** (usually only once during the lifetime of the process). ^(The xInit() 5493** method is passed a copy of the sqlite3_pcache_methods.pArg value.)^ 5494** The intent of the xInit() method is to set up global data structures 5495** required by the custom page cache implementation. 5496** ^(If the xInit() method is NULL, then the 5497** built-in default page cache is used instead of the application defined 5498** page cache.)^ 5499** 5500** ^The xShutdown() method is called by [sqlite3_shutdown()]. 5501** It can be used to clean up 5502** any outstanding resources before process shutdown, if required. 5503** ^The xShutdown() method may be NULL. 5504** 5505** ^SQLite automatically serializes calls to the xInit method, 5506** so the xInit method need not be threadsafe. ^The 5507** xShutdown method is only called from [sqlite3_shutdown()] so it does 5508** not need to be threadsafe either. All other methods must be threadsafe 5509** in multithreaded applications. 5510** 5511** ^SQLite will never invoke xInit() more than once without an intervening 5512** call to xShutdown(). 5513** 5514** ^SQLite invokes the xCreate() method to construct a new cache instance. 5515** SQLite will typically create one cache instance for each open database file, 5516** though this is not guaranteed. ^The 5517** first parameter, szPage, is the size in bytes of the pages that must 5518** be allocated by the cache. ^szPage will not be a power of two. ^szPage 5519** will the page size of the database file that is to be cached plus an 5520** increment (here called "R") of about 100 or 200. SQLite will use the 5521** extra R bytes on each page to store metadata about the underlying 5522** database page on disk. The value of R depends 5523** on the SQLite version, the target platform, and how SQLite was compiled. 5524** ^R is constant for a particular build of SQLite. ^The second argument to 5525** xCreate(), bPurgeable, is true if the cache being created will 5526** be used to cache database pages of a file stored on disk, or 5527** false if it is used for an in-memory database. The cache implementation 5528** does not have to do anything special based with the value of bPurgeable; 5529** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 5530** never invoke xUnpin() except to deliberately delete a page. 5531** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 5532** false will always have the "discard" flag set to true. 5533** ^Hence, a cache created with bPurgeable false will 5534** never contain any unpinned pages. 5535** 5536** ^(The xCachesize() method may be called at any time by SQLite to set the 5537** suggested maximum cache-size (number of pages stored by) the cache 5538** instance passed as the first argument. This is the value configured using 5539** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 5540** parameter, the implementation is not required to do anything with this 5541** value; it is advisory only. 5542** 5543** The xPagecount() method must return the number of pages currently 5544** stored in the cache, both pinned and unpinned. 5545** 5546** The xFetch() method locates a page in the cache and returns a pointer to 5547** the page, or a NULL pointer. 5548** A "page", in this context, means a buffer of szPage bytes aligned at an 5549** 8-byte boundary. The page to be fetched is determined by the key. ^The 5550** mimimum key value is 1. After it has been retrieved using xFetch, the page 5551** is considered to be "pinned". 5552** 5553** If the requested page is already in the page cache, then the page cache 5554** implementation must return a pointer to the page buffer with its content 5555** intact. If the requested page is not already in the cache, then the 5556** behavior of the cache implementation should use the value of the createFlag 5557** parameter to help it determined what action to take: 5558** 5559** <table border=1 width=85% align=center> 5560** <tr><th> createFlag <th> Behaviour when page is not already in cache 5561** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 5562** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 5563** Otherwise return NULL. 5564** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 5565** NULL if allocating a new page is effectively impossible. 5566** </table> 5567** 5568** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 5569** will only use a createFlag of 2 after a prior call with a createFlag of 1 5570** failed.)^ In between the to xFetch() calls, SQLite may 5571** attempt to unpin one or more cache pages by spilling the content of 5572** pinned pages to disk and synching the operating system disk cache. 5573** 5574** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 5575** as its second argument. If the third parameter, discard, is non-zero, 5576** then the page must be evicted from the cache. 5577** ^If the discard parameter is 5578** zero, then the page may be discarded or retained at the discretion of 5579** page cache implementation. ^The page cache implementation 5580** may choose to evict unpinned pages at any time. 5581** 5582** The cache must not perform any reference counting. A single 5583** call to xUnpin() unpins the page regardless of the number of prior calls 5584** to xFetch(). 5585** 5586** The xRekey() method is used to change the key value associated with the 5587** page passed as the second argument. If the cache 5588** previously contains an entry associated with newKey, it must be 5589** discarded. ^Any prior cache entry associated with newKey is guaranteed not 5590** to be pinned. 5591** 5592** When SQLite calls the xTruncate() method, the cache must discard all 5593** existing cache entries with page numbers (keys) greater than or equal 5594** to the value of the iLimit parameter passed to xTruncate(). If any 5595** of these pages are pinned, they are implicitly unpinned, meaning that 5596** they can be safely discarded. 5597** 5598** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 5599** All resources associated with the specified cache should be freed. ^After 5600** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 5601** handle invalid, and will not use it with any other sqlite3_pcache_methods 5602** functions. 5603*/ 5604typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 5605struct sqlite3_pcache_methods { 5606 void *pArg; 5607 int (*xInit)(void*); 5608 void (*xShutdown)(void*); 5609 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 5610 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 5611 int (*xPagecount)(sqlite3_pcache*); 5612 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 5613 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 5614 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 5615 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 5616 void (*xDestroy)(sqlite3_pcache*); 5617}; 5618 5619/* 5620** CAPI3REF: Online Backup Object 5621** 5622** The sqlite3_backup object records state information about an ongoing 5623** online backup operation. ^The sqlite3_backup object is created by 5624** a call to [sqlite3_backup_init()] and is destroyed by a call to 5625** [sqlite3_backup_finish()]. 5626** 5627** See Also: [Using the SQLite Online Backup API] 5628*/ 5629typedef struct sqlite3_backup sqlite3_backup; 5630 5631/* 5632** CAPI3REF: Online Backup API. 5633** 5634** The backup API copies the content of one database into another. 5635** It is useful either for creating backups of databases or 5636** for copying in-memory databases to or from persistent files. 5637** 5638** See Also: [Using the SQLite Online Backup API] 5639** 5640** ^Exclusive access is required to the destination database for the 5641** duration of the operation. ^However the source database is only 5642** read-locked while it is actually being read; it is not locked 5643** continuously for the entire backup operation. ^Thus, the backup may be 5644** performed on a live source database without preventing other users from 5645** reading or writing to the source database while the backup is underway. 5646** 5647** ^(To perform a backup operation: 5648** <ol> 5649** <li><b>sqlite3_backup_init()</b> is called once to initialize the 5650** backup, 5651** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 5652** the data between the two databases, and finally 5653** <li><b>sqlite3_backup_finish()</b> is called to release all resources 5654** associated with the backup operation. 5655** </ol>)^ 5656** There should be exactly one call to sqlite3_backup_finish() for each 5657** successful call to sqlite3_backup_init(). 5658** 5659** <b>sqlite3_backup_init()</b> 5660** 5661** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 5662** [database connection] associated with the destination database 5663** and the database name, respectively. 5664** ^The database name is "main" for the main database, "temp" for the 5665** temporary database, or the name specified after the AS keyword in 5666** an [ATTACH] statement for an attached database. 5667** ^The S and M arguments passed to 5668** sqlite3_backup_init(D,N,S,M) identify the [database connection] 5669** and database name of the source database, respectively. 5670** ^The source and destination [database connections] (parameters S and D) 5671** must be different or else sqlite3_backup_init(D,N,S,M) will file with 5672** an error. 5673** 5674** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 5675** returned and an error code and error message are store3d in the 5676** destination [database connection] D. 5677** ^The error code and message for the failed call to sqlite3_backup_init() 5678** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 5679** [sqlite3_errmsg16()] functions. 5680** ^A successful call to sqlite3_backup_init() returns a pointer to an 5681** [sqlite3_backup] object. 5682** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 5683** sqlite3_backup_finish() functions to perform the specified backup 5684** operation. 5685** 5686** <b>sqlite3_backup_step()</b> 5687** 5688** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 5689** the source and destination databases specified by [sqlite3_backup] object B. 5690** ^If N is negative, all remaining source pages are copied. 5691** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 5692** are still more pages to be copied, then the function resturns [SQLITE_OK]. 5693** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 5694** from source to destination, then it returns [SQLITE_DONE]. 5695** ^If an error occurs while running sqlite3_backup_step(B,N), 5696** then an [error code] is returned. ^As well as [SQLITE_OK] and 5697** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 5698** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 5699** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 5700** 5701** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 5702** <ol> 5703** <li> the destination database was opened read-only, or 5704** <li> the destination database is using write-ahead-log journaling 5705** and the destination and source page sizes differ, or 5706** <li> The destination database is an in-memory database and the 5707** destination and source page sizes differ. 5708** </ol>)^ 5709** 5710** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 5711** the [sqlite3_busy_handler | busy-handler function] 5712** is invoked (if one is specified). ^If the 5713** busy-handler returns non-zero before the lock is available, then 5714** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 5715** sqlite3_backup_step() can be retried later. ^If the source 5716** [database connection] 5717** is being used to write to the source database when sqlite3_backup_step() 5718** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 5719** case the call to sqlite3_backup_step() can be retried later on. ^(If 5720** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 5721** [SQLITE_READONLY] is returned, then 5722** there is no point in retrying the call to sqlite3_backup_step(). These 5723** errors are considered fatal.)^ The application must accept 5724** that the backup operation has failed and pass the backup operation handle 5725** to the sqlite3_backup_finish() to release associated resources. 5726** 5727** ^The first call to sqlite3_backup_step() obtains an exclusive lock 5728** on the destination file. ^The exclusive lock is not released until either 5729** sqlite3_backup_finish() is called or the backup operation is complete 5730** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 5731** sqlite3_backup_step() obtains a [shared lock] on the source database that 5732** lasts for the duration of the sqlite3_backup_step() call. 5733** ^Because the source database is not locked between calls to 5734** sqlite3_backup_step(), the source database may be modified mid-way 5735** through the backup process. ^If the source database is modified by an 5736** external process or via a database connection other than the one being 5737** used by the backup operation, then the backup will be automatically 5738** restarted by the next call to sqlite3_backup_step(). ^If the source 5739** database is modified by the using the same database connection as is used 5740** by the backup operation, then the backup database is automatically 5741** updated at the same time. 5742** 5743** <b>sqlite3_backup_finish()</b> 5744** 5745** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 5746** application wishes to abandon the backup operation, the application 5747** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 5748** ^The sqlite3_backup_finish() interfaces releases all 5749** resources associated with the [sqlite3_backup] object. 5750** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 5751** active write-transaction on the destination database is rolled back. 5752** The [sqlite3_backup] object is invalid 5753** and may not be used following a call to sqlite3_backup_finish(). 5754** 5755** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 5756** sqlite3_backup_step() errors occurred, regardless or whether or not 5757** sqlite3_backup_step() completed. 5758** ^If an out-of-memory condition or IO error occurred during any prior 5759** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 5760** sqlite3_backup_finish() returns the corresponding [error code]. 5761** 5762** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 5763** is not a permanent error and does not affect the return value of 5764** sqlite3_backup_finish(). 5765** 5766** <b>sqlite3_backup_remaining(), sqlite3_backup_pagecount()</b> 5767** 5768** ^Each call to sqlite3_backup_step() sets two values inside 5769** the [sqlite3_backup] object: the number of pages still to be backed 5770** up and the total number of pages in the source database file. 5771** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces 5772** retrieve these two values, respectively. 5773** 5774** ^The values returned by these functions are only updated by 5775** sqlite3_backup_step(). ^If the source database is modified during a backup 5776** operation, then the values are not updated to account for any extra 5777** pages that need to be updated or the size of the source database file 5778** changing. 5779** 5780** <b>Concurrent Usage of Database Handles</b> 5781** 5782** ^The source [database connection] may be used by the application for other 5783** purposes while a backup operation is underway or being initialized. 5784** ^If SQLite is compiled and configured to support threadsafe database 5785** connections, then the source database connection may be used concurrently 5786** from within other threads. 5787** 5788** However, the application must guarantee that the destination 5789** [database connection] is not passed to any other API (by any thread) after 5790** sqlite3_backup_init() is called and before the corresponding call to 5791** sqlite3_backup_finish(). SQLite does not currently check to see 5792** if the application incorrectly accesses the destination [database connection] 5793** and so no error code is reported, but the operations may malfunction 5794** nevertheless. Use of the destination database connection while a 5795** backup is in progress might also also cause a mutex deadlock. 5796** 5797** If running in [shared cache mode], the application must 5798** guarantee that the shared cache used by the destination database 5799** is not accessed while the backup is running. In practice this means 5800** that the application must guarantee that the disk file being 5801** backed up to is not accessed by any connection within the process, 5802** not just the specific connection that was passed to sqlite3_backup_init(). 5803** 5804** The [sqlite3_backup] object itself is partially threadsafe. Multiple 5805** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 5806** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 5807** APIs are not strictly speaking threadsafe. If they are invoked at the 5808** same time as another thread is invoking sqlite3_backup_step() it is 5809** possible that they return invalid values. 5810*/ 5811sqlite3_backup *sqlite3_backup_init( 5812 sqlite3 *pDest, /* Destination database handle */ 5813 const char *zDestName, /* Destination database name */ 5814 sqlite3 *pSource, /* Source database handle */ 5815 const char *zSourceName /* Source database name */ 5816); 5817int sqlite3_backup_step(sqlite3_backup *p, int nPage); 5818int sqlite3_backup_finish(sqlite3_backup *p); 5819int sqlite3_backup_remaining(sqlite3_backup *p); 5820int sqlite3_backup_pagecount(sqlite3_backup *p); 5821 5822/* 5823** CAPI3REF: Unlock Notification 5824** 5825** ^When running in shared-cache mode, a database operation may fail with 5826** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 5827** individual tables within the shared-cache cannot be obtained. See 5828** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 5829** ^This API may be used to register a callback that SQLite will invoke 5830** when the connection currently holding the required lock relinquishes it. 5831** ^This API is only available if the library was compiled with the 5832** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 5833** 5834** See Also: [Using the SQLite Unlock Notification Feature]. 5835** 5836** ^Shared-cache locks are released when a database connection concludes 5837** its current transaction, either by committing it or rolling it back. 5838** 5839** ^When a connection (known as the blocked connection) fails to obtain a 5840** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 5841** identity of the database connection (the blocking connection) that 5842** has locked the required resource is stored internally. ^After an 5843** application receives an SQLITE_LOCKED error, it may call the 5844** sqlite3_unlock_notify() method with the blocked connection handle as 5845** the first argument to register for a callback that will be invoked 5846** when the blocking connections current transaction is concluded. ^The 5847** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 5848** call that concludes the blocking connections transaction. 5849** 5850** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 5851** there is a chance that the blocking connection will have already 5852** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 5853** If this happens, then the specified callback is invoked immediately, 5854** from within the call to sqlite3_unlock_notify().)^ 5855** 5856** ^If the blocked connection is attempting to obtain a write-lock on a 5857** shared-cache table, and more than one other connection currently holds 5858** a read-lock on the same table, then SQLite arbitrarily selects one of 5859** the other connections to use as the blocking connection. 5860** 5861** ^(There may be at most one unlock-notify callback registered by a 5862** blocked connection. If sqlite3_unlock_notify() is called when the 5863** blocked connection already has a registered unlock-notify callback, 5864** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 5865** called with a NULL pointer as its second argument, then any existing 5866** unlock-notify callback is canceled. ^The blocked connections 5867** unlock-notify callback may also be canceled by closing the blocked 5868** connection using [sqlite3_close()]. 5869** 5870** The unlock-notify callback is not reentrant. If an application invokes 5871** any sqlite3_xxx API functions from within an unlock-notify callback, a 5872** crash or deadlock may be the result. 5873** 5874** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 5875** returns SQLITE_OK. 5876** 5877** <b>Callback Invocation Details</b> 5878** 5879** When an unlock-notify callback is registered, the application provides a 5880** single void* pointer that is passed to the callback when it is invoked. 5881** However, the signature of the callback function allows SQLite to pass 5882** it an array of void* context pointers. The first argument passed to 5883** an unlock-notify callback is a pointer to an array of void* pointers, 5884** and the second is the number of entries in the array. 5885** 5886** When a blocking connections transaction is concluded, there may be 5887** more than one blocked connection that has registered for an unlock-notify 5888** callback. ^If two or more such blocked connections have specified the 5889** same callback function, then instead of invoking the callback function 5890** multiple times, it is invoked once with the set of void* context pointers 5891** specified by the blocked connections bundled together into an array. 5892** This gives the application an opportunity to prioritize any actions 5893** related to the set of unblocked database connections. 5894** 5895** <b>Deadlock Detection</b> 5896** 5897** Assuming that after registering for an unlock-notify callback a 5898** database waits for the callback to be issued before taking any further 5899** action (a reasonable assumption), then using this API may cause the 5900** application to deadlock. For example, if connection X is waiting for 5901** connection Y's transaction to be concluded, and similarly connection 5902** Y is waiting on connection X's transaction, then neither connection 5903** will proceed and the system may remain deadlocked indefinitely. 5904** 5905** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 5906** detection. ^If a given call to sqlite3_unlock_notify() would put the 5907** system in a deadlocked state, then SQLITE_LOCKED is returned and no 5908** unlock-notify callback is registered. The system is said to be in 5909** a deadlocked state if connection A has registered for an unlock-notify 5910** callback on the conclusion of connection B's transaction, and connection 5911** B has itself registered for an unlock-notify callback when connection 5912** A's transaction is concluded. ^Indirect deadlock is also detected, so 5913** the system is also considered to be deadlocked if connection B has 5914** registered for an unlock-notify callback on the conclusion of connection 5915** C's transaction, where connection C is waiting on connection A. ^Any 5916** number of levels of indirection are allowed. 5917** 5918** <b>The "DROP TABLE" Exception</b> 5919** 5920** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 5921** always appropriate to call sqlite3_unlock_notify(). There is however, 5922** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 5923** SQLite checks if there are any currently executing SELECT statements 5924** that belong to the same connection. If there are, SQLITE_LOCKED is 5925** returned. In this case there is no "blocking connection", so invoking 5926** sqlite3_unlock_notify() results in the unlock-notify callback being 5927** invoked immediately. If the application then re-attempts the "DROP TABLE" 5928** or "DROP INDEX" query, an infinite loop might be the result. 5929** 5930** One way around this problem is to check the extended error code returned 5931** by an sqlite3_step() call. ^(If there is a blocking connection, then the 5932** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 5933** the special "DROP TABLE/INDEX" case, the extended error code is just 5934** SQLITE_LOCKED.)^ 5935*/ 5936int sqlite3_unlock_notify( 5937 sqlite3 *pBlocked, /* Waiting connection */ 5938 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 5939 void *pNotifyArg /* Argument to pass to xNotify */ 5940); 5941 5942 5943/* 5944** CAPI3REF: String Comparison 5945** 5946** ^The [sqlite3_strnicmp()] API allows applications and extensions to 5947** compare the contents of two buffers containing UTF-8 strings in a 5948** case-independent fashion, using the same definition of case independence 5949** that SQLite uses internally when comparing identifiers. 5950*/ 5951int sqlite3_strnicmp(const char *, const char *, int); 5952 5953/* 5954** CAPI3REF: Error Logging Interface 5955** 5956** ^The [sqlite3_log()] interface writes a message into the error log 5957** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 5958** ^If logging is enabled, the zFormat string and subsequent arguments are 5959** used with [sqlite3_snprintf()] to generate the final output string. 5960** 5961** The sqlite3_log() interface is intended for use by extensions such as 5962** virtual tables, collating functions, and SQL functions. While there is 5963** nothing to prevent an application from calling sqlite3_log(), doing so 5964** is considered bad form. 5965** 5966** The zFormat string must not be NULL. 5967** 5968** To avoid deadlocks and other threading problems, the sqlite3_log() routine 5969** will not use dynamically allocated memory. The log message is stored in 5970** a fixed-length buffer on the stack. If the log message is longer than 5971** a few hundred characters, it will be truncated to the length of the 5972** buffer. 5973*/ 5974void sqlite3_log(int iErrCode, const char *zFormat, ...); 5975 5976/* 5977** CAPI3REF: Write-Ahead Log Commit Hook 5978** 5979** ^The [sqlite3_wal_hook()] function is used to register a callback that 5980** will be invoked each time a database connection commits data to a 5981** [write-ahead log] (i.e. whenever a transaction is committed in 5982** [journal_mode | journal_mode=WAL mode]). 5983** 5984** ^The callback is invoked by SQLite after the commit has taken place and 5985** the associated write-lock on the database released, so the implementation 5986** may read, write or [checkpoint] the database as required. 5987** 5988** ^The first parameter passed to the callback function when it is invoked 5989** is a copy of the third parameter passed to sqlite3_wal_hook() when 5990** registering the callback. ^The second is a copy of the database handle. 5991** ^The third parameter is the name of the database that was written to - 5992** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 5993** is the number of pages currently in the write-ahead log file, 5994** including those that were just committed. 5995** 5996** The callback function should normally return [SQLITE_OK]. ^If an error 5997** code is returned, that error will propagate back up through the 5998** SQLite code base to cause the statement that provoked the callback 5999** to report an error, though the commit will have still occurred. If the 6000** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 6001** that does not correspond to any valid SQLite error code, the results 6002** are undefined. 6003** 6004** A single database handle may have at most a single write-ahead log callback 6005** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 6006** previously registered write-ahead log callback. ^Note that the 6007** [sqlite3_wal_autocheckpoint()] interface and the 6008** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 6009** those overwrite any prior [sqlite3_wal_hook()] settings. 6010*/ 6011void *sqlite3_wal_hook( 6012 sqlite3*, 6013 int(*)(void *,sqlite3*,const char*,int), 6014 void* 6015); 6016 6017/* 6018** CAPI3REF: Configure an auto-checkpoint 6019** 6020** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 6021** [sqlite3_wal_hook()] that causes any database on [database connection] D 6022** to automatically [checkpoint] 6023** after committing a transaction if there are N or 6024** more frames in the [write-ahead log] file. ^Passing zero or 6025** a negative value as the nFrame parameter disables automatic 6026** checkpoints entirely. 6027** 6028** ^The callback registered by this function replaces any existing callback 6029** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 6030** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 6031** configured by this function. 6032** 6033** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 6034** from SQL. 6035** 6036** ^Every new [database connection] defaults to having the auto-checkpoint 6037** enabled with a threshold of 1000 pages. The use of this interface 6038** is only necessary if the default setting is found to be suboptimal 6039** for a particular application. 6040*/ 6041int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 6042 6043/* 6044** CAPI3REF: Checkpoint a database 6045** 6046** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X 6047** on [database connection] D to be [checkpointed]. ^If X is NULL or an 6048** empty string, then a checkpoint is run on all databases of 6049** connection D. ^If the database connection D is not in 6050** [WAL | write-ahead log mode] then this interface is a harmless no-op. 6051** 6052** ^The [wal_checkpoint pragma] can be used to invoke this interface 6053** from SQL. ^The [sqlite3_wal_autocheckpoint()] interface and the 6054** [wal_autocheckpoint pragma] can be used to cause this interface to be 6055** run whenever the WAL reaches a certain size threshold. 6056*/ 6057int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 6058 6059/* 6060** Undo the hack that converts floating point types to integer for 6061** builds on processors without floating point support. 6062*/ 6063#ifdef SQLITE_OMIT_FLOATING_POINT 6064# undef double 6065#endif 6066 6067#ifdef __cplusplus 6068} /* End of the 'extern "C"' block */ 6069#endif 6070#endif 6071